[tor/release-0.4.1] Merge branch 'bug30649_040' into bug30649_maint_041

5 Sep 2019

diff --git a/.gitignore b/.gitignore
index a40cda02d..0865f981b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -168,6 +168,8 @@ uptime-*.json
 /src/lib/libtor-crypt-ops-testing.a
 /src/lib/libtor-ctime.a
 /src/lib/libtor-ctime-testing.a
+/src/lib/libtor-dispatch.a
+/src/lib/libtor-dispatch-testing.a
 /src/lib/libtor-encoding.a
 /src/lib/libtor-encoding-testing.a
 /src/lib/libtor-evloop.a
@@ -200,6 +202,8 @@ uptime-*.json
 /src/lib/libtor-osinfo-testing.a
 /src/lib/libtor-process.a
 /src/lib/libtor-process-testing.a
+/src/lib/libtor-pubsub.a
+/src/lib/libtor-pubsub-testing.a
 /src/lib/libtor-sandbox.a
 /src/lib/libtor-sandbox-testing.a
 /src/lib/libtor-string.a
diff --git a/.travis.yml b/.travis.yml
index 7d8877c2a..bbba0e204 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -42,15 +42,18 @@ matrix:
   ## include creates builds with gcc, linux
   include:
     ## We include a single coverage build with the best options for coverage
-    - env: COVERAGE_OPTIONS="--enable-coverage" HARDENING_OPTIONS=""
+    - env: COVERAGE_OPTIONS="--enable-coverage" HARDENING_OPTIONS="" TOR_TEST_RNG_SEED="636f766572616765"
     ## We only want to check these build option combinations once
     ## (they shouldn't vary by compiler or OS)
     ## We run rust and coverage with hardening off, which seems like enough
     # - env: HARDENING_OPTIONS=""
     ## We check asciidoc with distcheck, to make sure we remove doc products
-    - env: DISTCHECK="yes" ASCIIDOC_OPTIONS=""
+    - env: DISTCHECK="yes" ASCIIDOC_OPTIONS="" SKIP_MAKE_CHECK="yes"
+    # We also try running a hardened clang build with chutney on Linux.
+    - env: CHUTNEY="yes" SKIP_MAKE_CHECK="yes" CHUTNEY_ALLOW_FAILURES="2"
+      compiler: clang
     # We clone our stem repo and run `make test-stem`
-    - env: TEST_STEM="yes"
+    - env: TEST_STEM="yes" SKIP_MAKE_CHECK="yes"
     ## Check rust online with distcheck, to make sure we remove rust products
     - env: DISTCHECK="yes" RUST_OPTIONS="--enable-rust --enable-cargo-online-mode"
     ## Check disable module dirauth with and without rust
@@ -72,7 +75,7 @@ matrix:
   ## https://docs.travis-ci.com/user/customizing-the-build#matching-jobs-with-all...
   allow_failures:
     ## test-stem sometimes hangs on Travis
-    - env: TEST_STEM="yes"
+    - env: TEST_STEM="yes" SKIP_MAKE_CHECK="yes"
 
   exclude:
     ## gcc on OSX is less useful, because the default compiler is clang.
@@ -88,7 +91,7 @@ matrix:
     - compiler: gcc
       os: linux
       ## TOR_RUST_DEPENDENCIES is spelt RUST_DEPENDENCIES in 0.3.2
-      env: RUST_OPTIONS="--enable-rust" TOR_RUST_DEPENDENCIES=true HARDENING_OPTIONS=""
+      env: RUST_OPTIONS="--enable-rust" TOR_RUST_DEPENDENCIES=true
 
 ## (Linux only) Use the latest Linux image (Ubuntu Trusty)
 dist: trusty
@@ -175,6 +178,9 @@ install:
   - if [[ "$RUST_OPTIONS" != "" ]]; then source $HOME/.cargo/env; fi
   ## If we're testing rust builds in offline-mode, then set up our vendored dependencies
   - if [[ "$TOR_RUST_DEPENDENCIES" == "true" ]]; then export TOR_RUST_DEPENDENCIES=$PWD/src/ext/rust/crates; fi
+  ## If we're running chutney, install it.
+  - if [[ "$CHUTNEY" != "" ]]; then git clone --depth 1 https://github.com/torproject/chutney.git ; export CHUTNEY_PATH="$(pwd)/chutney"; fi
+  ## If we're running stem, install it.
   - if [[ "$TEST_STEM" != "" ]]; then git clone --depth 1 https://github.com/torproject/stem.git ; export STEM_SOURCE_DIR=`pwd`/stem; fi
   ##
   ## Finally, list installed package versions
@@ -189,7 +195,9 @@ install:
   - if [[ "$RUST_OPTIONS" != "" ]]; then cargo --version; fi
   ## Get python version
   - python --version
-  ## run stem tests if they are enabled.
+  ## If we're running chutney, show the chutney commit
+  - if [[ "$CHUTNEY" != "" ]]; then pushd "$CHUTNEY_PATH"; git log -1 ; popd ; fi
+  ## If we're running stem, show the stem version and commit
   - if [[ "$TEST_STEM" != "" ]]; then pushd stem; python -c "from stem import stem; print(stem.__version__);"; git log -1; popd; fi
 
 script:
@@ -200,10 +208,12 @@ script:
   - echo "Configure flags are $CONFIGURE_FLAGS"
   - ./configure $CONFIGURE_FLAGS
   ## We run `make check` because that's what https://jenkins.torproject.org does.
-  - if [[ "$DISTCHECK" == "" && "$TEST_STEM" == "" ]]; then make check; fi
-  ## Diagnostic for bug 29437: kill stem if it hangs for 15 minutes
-  - if [[ "$TEST_STEM" != "" ]]; then make src/app/tor; timelimit -p -t 540 -s USR1 -T 30 -S ABRT python3 "$STEM_SOURCE_DIR"/run_tests.py --tor src/app/tor --integ --log notice --target RUN_ALL; fi
-  - if [[ "$DISTCHECK" != "" && "$TEST_STEM" == "" ]]; then make distcheck DISTCHECK_CONFIGURE_FLAGS="$CONFIGURE_FLAGS"; fi
+  - if [[ "$SKIP_MAKE_CHECK" == "" ]]; then make check; fi
+  - if [[ "$DISTCHECK" != "" ]]; then make distcheck DISTCHECK_CONFIGURE_FLAGS="$CONFIGURE_FLAGS"; fi
+  - if [[ "$CHUTNEY" != "" ]]; then make test-network-all; fi
+  ## Diagnostic for bug 29437: kill stem if it hangs for 9.5 minutes
+  ## Travis will kill the job after 10 minutes with no output
+  - if [[ "$TEST_STEM" != "" ]]; then make src/app/tor; timelimit -p -t 540 -s USR1 -T 30 -S ABRT python3 "$STEM_SOURCE_DIR"/run_tests.py --tor src/app/tor --integ --test control.controller --test control.base_controller --test process --log TRACE --log-file stem.log; fi
   ## If this build was one that produced coverage, upload it.
   - if [[ "$COVERAGE_OPTIONS" != "" ]]; then coveralls -b . --exclude src/test --exclude src/trunnel --gcov-options '\-p' || echo "Coverage failed"; fi
 
@@ -212,11 +222,13 @@ after_failure:
   ## But the log is too long for travis' rendered view, so tail it.
   - tail -1000 config.log || echo "tail failed"
   ## `make check` will leave a log file with more details of test failures.
-  - if [[ "$DISTCHECK" == "" ]]; then cat test-suite.log || echo "cat failed"; fi
+  - if [[ "$SKIP_MAKE_CHECK" == "" ]]; then cat test-suite.log || echo "cat failed"; fi
   ## `make distcheck` puts it somewhere different.
   - if [[ "$DISTCHECK" != "" ]]; then make show-distdir-testlog || echo "make failed"; fi
   - if [[ "$DISTCHECK" != "" ]]; then make show-distdir-core || echo "make failed"; fi
-  - if [[ "$TEST_STEM" != "" ]]; then cat "$STEM_SOURCE_DIR"/test/data/tor_log || echo "cat failed"; fi
+  - if [[ "$CHUTNEY" != "" ]]; then ls test_network_log || echo "ls failed"; cat test_network_log/* || echo "cat failed"; fi
+  - if [[ "$TEST_STEM" != "" ]]; then tail -1000 "$STEM_SOURCE_DIR"/test/data/tor_log || echo "tail failed"; fi
+  - if [[ "$TEST_STEM" != "" ]]; then grep -v "SocketClosed" stem.log | tail -1000 || echo "grep | tail failed"; fi
 
 before_cache:
   ## Delete all gcov files.
diff --git a/ChangeLog b/ChangeLog
index e6bcc806e..d44ce316c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,1086 @@
+Changes in version 0.4.1.2-alpha - 2019-06-06
+  Tor 0.4.1.2-alpha resolves numerous bugs--some of them from the
+  previous alpha, and some much older. It also contains minor testing
+  improvements, and an improvement to the security of our authenticated
+  SENDME implementation.
+
+  o Major bugfixes (bridges):
+    - Consider our directory information to have changed when our list
+      of bridges changes. Previously, Tor would not re-compute the
+      status of its directory information when bridges changed, and
+      therefore would not realize that it was no longer able to build
+      circuits. Fixes part of bug 29875.
+    - Do not count previously configured working bridges towards our
+      total of working bridges. Previously, when Tor's list of bridges
+      changed, it would think that the old bridges were still usable,
+      and delay fetching router descriptors for the new ones. Fixes part
+      of bug 29875; bugfix on 0.3.0.1-alpha.
+
+  o Major bugfixes (flow control, SENDME):
+    - Decrement the stream-level package window after packaging a cell.
+      Previously, it was done inside a log_debug() call, meaning that if
+      debug logs were not enabled, the decrement would never happen, and
+      thus the window would be out of sync with the other end point.
+      Fixes bug 30628; bugfix on 0.4.1.1-alpha.
+
+  o Major bugfixes (onion service reachability):
+    - Properly clean up the introduction point map and associated state
+      when circuits change purpose from onion service circuits to
+      pathbias, measurement, or other circuit types. This may fix some
+      instances of introduction point failure. Fixes bug 29034; bugfix
+      on 0.3.2.1-alpha.
+
+  o Minor features (authenticated SENDME):
+    - Ensure that there is enough randomness on every circuit to prevent
+      an attacker from successfully predicting the hashes they will need
+      to include in authenticated SENDME cells. At a random interval, if
+      we have not sent randomness already, we now leave some extra space
+      at the end of a cell that we can fill with random bytes. Closes
+      ticket 26846.
+
+  o Minor features (continuous integration):
+    - When running coverage builds on Travis, we now set
+      TOR_TEST_RNG_SEED, to avoid RNG-based coverage differences. Part
+      of ticket 28878.
+
+  o Minor features (maintenance):
+    - Add a new "make autostyle" target that developers can use to apply
+      all automatic Tor style and consistency conversions to the
+      codebase. Closes ticket 30539.
+
+  o Minor features (testing):
+    - The circuitpadding tests now use a reproducible RNG implementation,
+      so that if a test fails, we can learn why. Part of ticket 28878.
+    - Tor's tests now support an environment variable, TOR_TEST_RNG_SEED,
+      to set the RNG seed for tests that use a reproducible RNG. Part of
+      ticket 28878.
+    - When running tests in coverage mode, take additional care to make
+      our coverage deterministic, so that we can accurately track
+      changes in code coverage. Closes ticket 30519.
+
+  o Minor bugfixes (configuration, proxies):
+    - Fix a bug that prevented us from supporting SOCKS5 proxies that
+      want authentication along with configured (but unused!)
+      ClientTransportPlugins. Fixes bug 29670; bugfix on 0.2.6.1-alpha.
+
+  o Minor bugfixes (controller):
+    - POSTDESCRIPTOR requests should work again. Previously, they were
+      broken if a "purpose=" flag was specified. Fixes bug 30580; bugfix
+      on 0.4.1.1-alpha.
+    - Repair the HSFETCH command so that it works again. Previously, it
+      expected a body when it shouldn't have. Fixes bug 30646; bugfix
+      on 0.4.1.1-alpha.
+
+  o Minor bugfixes (developer tooling):
+    - Fix pre-push hook to allow fixup and squash commits when pushing
+      to non-upstream git remote. Fixes bug 30286; bugfix
+      on 0.4.0.1-alpha.
+
+  o Minor bugfixes (directory authority):
+    - Move the "bandwidth-file-headers" line in directory authority
+      votes so that it conforms to dir-spec.txt. Fixes bug 30316; bugfix
+      on 0.3.5.1-alpha.
+
+  o Minor bugfixes (NetBSD):
+    - Fix usage of minherit() on NetBSD and other platforms that define
+      MAP_INHERIT_{ZERO,NONE} instead of INHERIT_{ZERO,NONE}. Fixes bug
+      30614; bugfix on 0.4.0.2-alpha. Patch from Taylor Campbell.
+
+  o Minor bugfixes (out-of-memory handler):
+    - When purging the DNS cache because of an out-of-memory condition,
+      try purging just the older entries at first. Previously, we would
+      always purge the whole thing. Fixes bug 29617; bugfix
+      on 0.3.5.1-alpha.
+
+  o Minor bugfixes (portability):
+    - Avoid crashing in our tor_vasprintf() implementation on systems
+      that define neither vasprintf() nor _vscprintf(). (This bug has
+      been here long enough that we question whether people are running
+      Tor on such systems, but we're applying the fix out of caution.)
+      Fixes bug 30561; bugfix on 0.2.8.2-alpha. Found and fixed by
+      Tobias Stoeckmann.
+
+  o Minor bugfixes (shutdown, libevent, memory safety):
+    - Avoid use-after-free bugs when shutting down, by making sure that
+      we shut down libevent only after shutting down all of its users.
+      We believe these are harmless in practice, since they only occur
+      on the shutdown path, and do not involve any attacker-controlled
+      data. Fixes bug 30629; bugfix on 0.4.1.1-alpha.
+
+  o Minor bugfixes (static analysis):
+    - Fix several spurious Coverity warnings about the unit tests, to
+      lower our chances of missing real warnings in the future. Fixes
+      bug 30150; bugfix on 0.3.5.1-alpha and various other Tor versions.
+
+  o Testing:
+    - Specify torrc paths (with empty files) when launching tor in
+      integration tests; refrain from reading user and system torrcs.
+      Resolves issue 29702.
+
+
+Changes in version 0.4.1.1-alpha - 2019-05-22
+  This is the first alpha in the 0.4.1.x series. It introduces
+  lightweight circuit padding to make some onion-service circuits harder
+  to distinguish, includes a new "authenticated SENDME" feature to make
+  certain denial-of-service attacks more difficult, and improves
+  performance in several areas.
+
+  o Major features (circuit padding):
+    - Onion service clients now add padding cells at the start of their
+      INTRODUCE and RENDEZVOUS circuits, to make those circuits' traffic
+      look more like general purpose Exit traffic. The overhead for this
+      is 2 extra cells in each direction for RENDEZVOUS circuits, and 1
+      extra upstream cell and 10 downstream cells for INTRODUCE
+      circuits. This feature is only enabled when also supported by the
+      circuit's middle node. (Clients may specify fixed middle nodes
+      with the MiddleNodes option, and may force-disable this feature
+      with the CircuitPadding torrc.) Closes ticket 28634.
+
+  o Major features (code organization):
+    - Tor now includes a generic publish-subscribe message-passing
+      subsystem that we can use to organize intermodule dependencies. We
+      hope to use this to reduce dependencies between modules that don't
+      need to be related, and to generally simplify our codebase. Closes
+      ticket 28226.
+
+  o Major features (controller protocol):
+    - Controller commands are now parsed using a generalized parsing
+      subsystem. Previously, each controller command was responsible for
+      parsing its own input, which led to strange inconsistencies.
+      Closes ticket 30091.
+
+  o Major features (flow control):
+    - Implement authenticated SENDMEs as detailed in proposal 289. A
+      SENDME cell now includes the digest of the traffic that it
+      acknowledges, so that once an end point receives the SENDME, it
+      can confirm the other side's knowledge of the previous cells that
+      were sent, and prevent certain types of denial-of-service attacks.
+      This behavior is controlled by two new consensus parameters: see
+      the proposal for more details. Fixes ticket 26288.
+
+  o Major features (performance):
+    - Our node selection algorithm now excludes nodes in linear time.
+      Previously, the algorithm was quadratic, which could slow down
+      heavily used onion services. Closes ticket 30307.
+
+  o Major features (performance, RNG):
+    - Tor now constructs a fast secure pseudorandom number generator for
+      each thread, to use when performance is critical. This PRNG is
+      based on AES-CTR, using a buffering construction similar to
+      libottery and the (newer) OpenBSD arc4random() code. It
+      outperforms OpenSSL 1.1.1a's CSPRNG by roughly a factor of 100 for
+      small outputs. Although we believe it to be cryptographically
+      strong, we are only using it when necessary for performance.
+      Implements tickets 29023 and 29536.
+
+  o Major bugfixes (onion service v3):
+    - Fix an unreachable bug in which an introduction point could try to
+      send an INTRODUCE_ACK with a status code that Trunnel would refuse
+      to encode, leading the relay to assert(). We've consolidated the
+      ABI values into Trunnel now. Fixes bug 30454; bugfix
+      on 0.3.0.1-alpha.
+    - Clients can now handle unknown status codes from INTRODUCE_ACK
+      cells. (The NACK behavior will stay the same.) This will allow us
+      to extend status codes in the future without breaking the normal
+      client behavior. Fixes another part of bug 30454; bugfix
+      on 0.3.0.1-alpha.
+
+  o Minor features (circuit padding):
+    - We now use a fast PRNG when scheduling circuit padding. Part of
+      ticket 28636.
+    - Allow the padding machine designer to pick the edges of their
+      histogram instead of trying to compute them automatically using an
+      exponential formula. Resolves some undefined behavior in the case
+      of small histograms and allows greater flexibility on machine
+      design. Closes ticket 29298; bugfix on 0.4.0.1-alpha.
+    - Allow circuit padding machines to hold a circuit open until they
+      are done padding it. Closes ticket 28780.
+
+  o Minor features (compile-time modules):
+    - Add a "--list-modules" command to print a list of which compile-
+      time modules are enabled. Closes ticket 30452.
+
+  o Minor features (continuous integration):
+    - Remove sudo configuration lines from .travis.yml as they are no
+      longer needed with current Travis build environment. Resolves
+      issue 30213.
+    - In Travis, show stem's tor log after failure. Closes ticket 30234.
+
+  o Minor features (controller):
+    - Add onion service version 3 support to the HSFETCH command.
+      Previously, only version 2 onion services were supported. Closes
+      ticket 25417. Patch by Neel Chauhan.
+
+  o Minor features (debugging):
+    - Introduce tor_assertf() and tor_assertf_nonfatal() to enable
+      logging of additional information during assert failure. Now we
+      can use format strings to include information for trouble
+      shooting. Resolves ticket 29662.
+
+  o Minor features (defense in depth):
+    - In smartlist_remove_keeporder(), set unused pointers to NULL, in
+      case a bug causes them to be used later. Closes ticket 30176.
+      Patch from Tobias Stoeckmann.
+    - Tor now uses a cryptographically strong PRNG even for decisions
+      that we do not believe are security-sensitive. Previously, for
+      performance reasons, we had used a trivially predictable linear
+      congruential generator algorithm for certain load-balancing and
+      statistical sampling decisions. Now we use our fast RNG in those
+      cases. Closes ticket 29542.
+
+  o Minor features (developer tools):
+    - Tor's "practracker" test script now checks for files and functions
+      that seem too long and complicated. Existing overlong functions
+      and files are accepted for now, but should eventually be
+      refactored. Closes ticket 29221.
+    - Add some scripts used for git maintenance to scripts/git. Closes
+      ticket 29391.
+    - Call practracker from pre-push and pre-commit git hooks to let
+      developers know if they made any code style violations. Closes
+      ticket 30051.
+    - Add a script to check that each header has a well-formed and
+      unique guard macro. Closes ticket 29756.
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the May 13 2019 Maxmind GeoLite2
+      Country database. Closes ticket 30522.
+
+  o Minor features (HTTP tunnel):
+    - Return an informative web page when the HTTPTunnelPort is used as
+      an HTTP proxy. Closes ticket 27821, patch by "eighthave".
+
+  o Minor features (IPv6, v3 onion services):
+    - Make v3 onion services put IPv6 addresses in service descriptors.
+      Before this change, service descriptors only contained IPv4
+      addresses. Implements 26992.
+
+  o Minor features (modularity):
+    - The "--disable-module-dirauth" compile-time option now disables
+      even more dirauth-only code. Closes ticket 30345.
+
+  o Minor features (performance):
+    - Use OpenSSL's implementations of SHA3 when available (in OpenSSL
+      1.1.1 and later), since they tend to be faster than tiny-keccak.
+      Closes ticket 28837.
+
+  o Minor features (testing):
+    - Tor's unit test code now contains helper functions to replace the
+      PRNG with a deterministic or reproducible version for testing.
+      Previously, various tests implemented this in various ways.
+      Implements ticket 29732.
+    - We now have a script, cov-test-determinism.sh, to identify places
+      where our unit test coverage has become nondeterministic. Closes
+      ticket 29436.
+    - Check that representative subsets of values of `int` and `unsigned
+      int` can be represented by `void *`. Resolves issue 29537.
+
+  o Minor bugfixes (bridge authority):
+    - Bridge authorities now set bridges as running or non-running when
+      about to dump their status to a file. Previously, they set bridges
+      as running in response to a GETINFO command, but those shouldn't
+      modify data structures. Fixes bug 24490; bugfix on 0.2.0.13-alpha.
+      Patch by Neel Chauhan.
+
+  o Minor bugfixes (channel padding statistics):
+    - Channel padding write totals and padding-enabled totals are now
+      counted properly in relay extrainfo descriptors. Fixes bug 29231;
+      bugfix on 0.3.1.1-alpha.
+
+  o Minor bugfixes (circuit padding):
+    - Add a "CircuitPadding" torrc option to disable circuit padding.
+      Fixes bug 28693; bugfix on 0.4.0.1-alpha.
+    - Allow circuit padding machines to specify that they do not
+      contribute much overhead, and provide consensus flags and torrc
+      options to force clients to only use these low overhead machines.
+      Fixes bug 29203; bugfix on 0.4.0.1-alpha.
+    - Provide a consensus parameter to fully disable circuit padding, to
+      be used in emergency network overload situations. Fixes bug 30173;
+      bugfix on 0.4.0.1-alpha.
+    - The circuit padding subsystem will no longer schedule padding if
+      dormant mode is enabled. Fixes bug 28636; bugfix on 0.4.0.1-alpha.
+    - Inspect a circuit-level cell queue before sending padding, to
+      avoid sending padding while too much data is already queued. Fixes
+      bug 29204; bugfix on 0.4.0.1-alpha.
+    - Avoid calling monotime_absolute_usec() in circuit padding machines
+      that do not use token removal or circuit RTT estimation. Fixes bug
+      29085; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (compilation, unusual configurations):
+    - Avoid failures when building with the ALL_BUGS_ARE_FATAL option
+      due to missing declarations of abort(), and prevent other such
+      failures in the future. Fixes bug 30189; bugfix on 0.3.4.1-alpha.
+
+  o Minor bugfixes (controller protocol):
+    - Teach the controller parser to distinguish an object preceded by
+      an argument list from one without. Previously, it couldn't
+      distinguish an argument list from the first line of a multiline
+      object. Fixes bug 29984; bugfix on 0.2.3.8-alpha.
+
+  o Minor bugfixes (directory authority, ipv6):
+    - Directory authorities with IPv6 support now always mark themselves
+      as reachable via IPv6. Fixes bug 24338; bugfix on 0.4.0.2-alpha.
+      Patch by Neel Chauhan.
+
+  o Minor bugfixes (documentation):
+    - Improve the documentation for using MapAddress with ".exit". Fixes
+      bug 30109; bugfix on 0.1.0.1-rc.
+    - Improve the monotonic time module and function documentation to
+      explain what "monotonic" actually means, and document some results
+      that have surprised people. Fixes bug 29640; bugfix
+      on 0.2.9.1-alpha.
+    - Use proper formatting when providing an example on quoting options
+      that contain whitespace. Fixes bug 29635; bugfix on 0.2.3.18-rc.
+
+  o Minor bugfixes (logging):
+    - Do not log a warning when running with an OpenSSL version other
+      than the one Tor was compiled with, if the two versions should be
+      compatible. Previously, we would warn whenever the version was
+      different. Fixes bug 30190; bugfix on 0.2.4.2-alpha.
+    - Warn operators when the MyFamily option is set but ContactInfo is
+      missing, as the latter should be set too. Fixes bug 25110; bugfix
+      on 0.3.3.1-alpha.
+
+  o Minor bugfixes (memory leak):
+    - Avoid a minor memory leak that could occur on relays when failing
+      to create a "keys" directory. Fixes bug 30148; bugfix
+      on 0.3.3.1-alpha.
+
+  o Minor bugfixes (onion services):
+    - Avoid a GCC 9.1.1 warning (and possible crash depending on libc
+      implemenation) when failing to load an onion service client
+      authorization file. Fixes bug 30475; bugfix on 0.3.5.1-alpha.
+    - When refusing to launch a controller's HSFETCH request because of
+      rate-limiting, respond to the controller with a new response,
+      "QUERY_RATE_LIMITED". Previously, we would log QUERY_NO_HSDIR for
+      this case. Fixes bug 28269; bugfix on 0.3.1.1-alpha. Patch by
+      Neel Chauhan.
+    - When relaunching a circuit to a rendezvous service, mark the
+      circuit as needing high-uptime routers as appropriate. Fixes bug
+      17357; bugfix on 0.4.0.2-alpha. Patch by Neel Chauhan.
+    - Stop ignoring IPv6 link specifiers sent to v3 onion services.
+      (IPv6 support for v3 onion services is still incomplete: see
+      ticket 23493 for details.) Fixes bug 23588; bugfix on
+      0.3.2.1-alpha. Patch by Neel Chauhan.
+
+  o Minor bugfixes (onion services, performance):
+    - When building circuits to onion services, call tor_addr_parse()
+      less often. Previously, we called tor_addr_parse() in
+      circuit_is_acceptable() even if its output wasn't used. This
+      change should improve performance when building circuits. Fixes
+      bug 22210; bugfix on 0.2.8.12. Patch by Neel Chauhan.
+
+  o Minor bugfixes (performance):
+    - When checking whether a node is a bridge, use a fast check to make
+      sure that its identity is set. Previously, we used a constant-time
+      check, which is not necessary in this case. Fixes bug 30308;
+      bugfix on 0.3.5.1-alpha.
+
+  o Minor bugfixes (pluggable transports):
+    - Tor now sets TOR_PT_EXIT_ON_STDIN_CLOSE=1 for client transports as
+      well as servers. Fixes bug 25614; bugfix on 0.2.7.1-alpha.
+
+  o Minor bugfixes (probability distributions):
+    - Refactor and improve parts of the probability distribution code
+      that made Coverity complain. Fixes bug 29805; bugfix
+      on 0.4.0.1-alpha.
+
+  o Minor bugfixes (python):
+    - Stop assuming that /usr/bin/python3 exists. For scripts that work
+      with python2, use /usr/bin/python. Otherwise, use /usr/bin/env
+      python3. Fixes bug 29913; bugfix on 0.2.5.3-alpha.
+
+  o Minor bugfixes (relay):
+    - When running as a relay, if IPv6Exit is set to 1 while ExitRelay
+      is auto, act as if ExitRelay is 1. Previously, we would ignore
+      IPv6Exit if ExitRelay was 0 or auto. Fixes bug 29613; bugfix on
+      0.3.5.1-alpha. Patch by Neel Chauhan.
+
+  o Minor bugfixes (stats):
+    - When ExtraInfoStatistics is 0, stop including bandwidth usage
+      statistics, GeoIPFile hashes, ServerTransportPlugin lines, and
+      bridge statistics by country in extra-info documents. Fixes bug
+      29018; bugfix on 0.2.4.1-alpha.
+
+  o Minor bugfixes (testing):
+    - Call setrlimit() to disable core dumps in test_bt_cl.c. Previously
+      we used `ulimit -c` in test_bt.sh, which violates POSIX shell
+      compatibility. Fixes bug 29061; bugfix on 0.3.5.1-alpha.
+    - Fix some incorrect code in the v3 onion service unit tests. Fixes
+      bug 29243; bugfix on 0.3.2.1-alpha.
+    - In the "routerkeys/*" tests, check the return values of mkdir()
+      for possible failures. Fixes bug 29939; bugfix on 0.2.7.2-alpha.
+      Found by Coverity as CID 1444254.
+    - Split test_utils_general() into several smaller test functions.
+      This makes it easier to perform resource deallocation on assert
+      failure, and fixes Coverity warnings CID 1444117 and CID 1444118.
+      Fixes bug 29823; bugfix on 0.2.9.1-alpha.
+
+  o Minor bugfixes (tor-resolve):
+    - Fix a memory leak in tor-resolve that could happen if Tor gave it
+      a malformed SOCKS response. (Memory leaks in tor-resolve don't
+      actually matter, but it's good to fix them anyway.) Fixes bug
+      30151; bugfix on 0.4.0.1-alpha.
+
+  o Code simplification and refactoring:
+    - Abstract out the low-level formatting of replies on the control
+      port. Implements ticket 30007.
+    - Add several assertions in an attempt to fix some Coverity
+      warnings. Closes ticket 30149.
+    - Introduce a connection_dir_buf_add() helper function that checks
+      for compress_state of dir_connection_t and automatically writes a
+      string to directory connection with or without compression.
+      Resolves issue 28816.
+    - Make the base32_decode() API return the number of bytes written,
+      for consistency with base64_decode(). Closes ticket 28913.
+    - Move most relay-only periodic events out of mainloop.c into the
+      relay subsystem. Closes ticket 30414.
+    - Refactor and encapsulate parts of the codebase that manipulate
+      crypt_path_t objects. Resolves issue 30236.
+    - Refactor several places in our code that Coverity incorrectly
+      believed might have memory leaks. Closes ticket 30147.
+    - Remove redundant return values in crypto_format, and the
+      associated return value checks elsewhere in the code. Make the
+      implementations in crypto_format consistent, and remove redundant
+      code. Resolves ticket 29660.
+    - Rename tor_mem_is_zero() to fast_mem_is_zero(), to emphasize that
+      it is not a constant-time function. Closes ticket 30309.
+    - Replace hs_desc_link_specifier_t with link_specifier_t, and remove
+      all hs_desc_link_specifier_t-specific code. Fixes bug 22781;
+      bugfix on 0.3.2.1-alpha.
+    - Simplify v3 onion service link specifier handling code. Fixes bug
+      23576; bugfix on 0.3.2.1-alpha.
+    - Split crypto_digest.c into NSS code, OpenSSL code, and shared
+      code. Resolves ticket 29108.
+    - Split control.c into several submodules, in preparation for
+      distributing its current responsibilities throughout the codebase.
+      Closes ticket 29894.
+    - Start to move responsibility for knowing about periodic events to
+      the appropriate subsystems, so that the mainloop doesn't need to
+      know all the periodic events in the rest of the codebase.
+      Implements tickets 30293 and 30294.
+
+  o Documentation:
+    - Document how to find git commits and tags for bug fixes in
+      CodingStandards.md. Update some file documentation. Closes
+      ticket 30261.
+
+  o Removed features:
+    - Remove the linux-tor-prio.sh script from contrib/operator-tools
+      directory. Resolves issue 29434.
+    - Remove the obsolete OpenSUSE initscript. Resolves issue 30076.
+    - Remove the obsolete script at contrib/dist/tor.sh.in. Resolves
+      issue 30075.
+
+  o Code simplification and refactoring (shell scripts):
+    - Clean up many of our shell scripts to fix shellcheck warnings.
+      These include autogen.sh (ticket 26069), test_keygen.sh (ticket
+      29062), test_switch_id.sh (ticket 29065), test_rebind.sh (ticket
+      29063), src/test/fuzz/minimize.sh (ticket 30079), test_rust.sh
+      (ticket 29064), torify (ticket 29070), asciidoc-helper.sh (29926),
+      fuzz_multi.sh (30077), fuzz_static_testcases.sh (ticket 29059),
+      nagios-check-tor-authority-cert (ticket 29071),
+      src/test/fuzz/fixup_filenames.sh (ticket 30078), test-network.sh
+      (ticket 29060), test_key_expiration.sh (ticket 30002),
+      zero_length_keys.sh (ticket 29068), and test_workqueue_*.sh
+      (ticket 29067).
+
+  o Testing (chutney):
+    - In "make test-network-all", test IPv6-only v3 single onion
+      services, using the chutney network single-onion-v23-ipv6-md.
+      Closes ticket 27251.
+
+
+Changes in version 0.4.0.5 - 2019-05-02
+  This is the first stable release in the 0.4.0.x series. It contains
+  improvements for power management and bootstrap reporting, as well as
+  preliminary backend support for circuit padding to prevent some kinds
+  of traffic analysis. It also continues our work in refactoring Tor for
+  long-term maintainability.
+
+  Per our support policy, we will support the 0.4.0.x series for nine
+  months, or until three months after the release of a stable 0.4.1.x:
+  whichever is longer. If you need longer-term support, please stick
+  with 0.3.5.x, which will we plan to support until Feb 2022.
+
+  Below are the changes since 0.4.0.4-rc. For a complete list of changes
+  since 0.3.5.7, see the ReleaseNotes file.
+
+  o Minor features (continuous integration):
+    - In Travis, tell timelimit to use stem's backtrace signals, and
+      launch python directly from timelimit, so python receives the
+      signals from timelimit, rather than make. Closes ticket 30117.
+
+  o Minor features (diagnostic):
+    - Add more diagnostic log messages in an attempt to solve the issue
+      of NUL bytes appearing in a microdescriptor cache. Related to
+      ticket 28223.
+
+  o Minor features (testing):
+    - Use the approx_time() function when setting the "Expires" header
+      in directory replies, to make them more testable. Needed for
+      ticket 30001.
+
+  o Minor bugfixes (rust):
+    - Abort on panic in all build profiles, instead of potentially
+      unwinding into C code. Fixes bug 27199; bugfix on 0.3.3.1-alpha.
+
+  o Minor bugfixes (shellcheck):
+    - Look for scripts in their correct locations during "make
+      shellcheck". Previously we had looked in the wrong place during
+      out-of-tree builds. Fixes bug 30263; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (testing):
+    - Check the time in the "Expires" header using approx_time(). Fixes
+      bug 30001; bugfix on 0.4.0.4-rc.
+
+  o Minor bugfixes (UI):
+    - Lower log level of unlink() errors during bootstrap. Fixes bug
+      29930; bugfix on 0.4.0.1-alpha.
+
+
+Changes in version 0.4.0.4-rc - 2019-04-11
+  Tor 0.4.0.4-rc is the first release candidate in its series; it fixes
+  several bugs from earlier versions, including some that had affected
+  stability, and one that prevented relays from working with NSS.
+
+  o Major bugfixes (NSS, relay):
+    - When running with NSS, disable TLS 1.2 ciphersuites that use
+      SHA384 for their PRF. Due to an NSS bug, the TLS key exporters for
+      these ciphersuites don't work -- which caused relays to fail to
+      handshake with one another when these ciphersuites were enabled.
+      Fixes bug 29241; bugfix on 0.3.5.1-alpha.
+
+  o Minor features (bandwidth authority):
+    - Make bandwidth authorities ignore relays that are reported in the
+      bandwidth file with the flag "vote=0". This change allows us to
+      report unmeasured relays for diagnostic reasons without including
+      their bandwidth in the bandwidth authorities' vote. Closes
+      ticket 29806.
+    - When a directory authority is using a bandwidth file to obtain the
+      bandwidth values that will be included in the next vote, serve
+      this bandwidth file at /tor/status-vote/next/bandwidth. Closes
+      ticket 21377.
+
+  o Minor features (circuit padding):
+    - Stop warning about undefined behavior in the probability
+      distribution tests. Float division by zero may technically be
+      undefined behavior in C, but it's well defined in IEEE 754.
+      Partial backport of 29298. Closes ticket 29527; bugfix
+      on 0.4.0.1-alpha.
+
+  o Minor features (continuous integration):
+    - On Travis Rust builds, cleanup Rust registry and refrain from
+      caching the "target/" directory to speed up builds. Resolves
+      issue 29962.
+
+  o Minor features (dormant mode):
+    - Add a DormantCanceledByStartup option to tell Tor that it should
+      treat a startup event as cancelling any previous dormant state.
+      Integrators should use this option with caution: it should only be
+      used if Tor is being started because of something that the user
+      did, and not if Tor is being automatically started in the
+      background. Closes ticket 29357.
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the April 2 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29992.
+
+  o Minor features (NSS, diagnostic):
+    - Try to log an error from NSS (if there is any) and a more useful
+      description of our situation if we are using NSS and a call to
+      SSL_ExportKeyingMaterial() fails. Diagnostic for ticket 29241.
+
+  o Minor bugfixes (security):
+    - Fix a potential double free bug when reading huge bandwidth files.
+      The issue is not exploitable in the current Tor network because
+      the vulnerable code is only reached when directory authorities
+      read bandwidth files, but bandwidth files come from a trusted
+      source (usually the authorities themselves). Furthermore, the
+      issue is only exploitable in rare (non-POSIX) 32-bit architectures,
+      which are not used by any of the current authorities. Fixes bug
+      30040; bugfix on 0.3.5.1-alpha. Bug found and fixed by
+      Tobias Stoeckmann.
+    - Verify in more places that we are not about to create a buffer
+      with more than INT_MAX bytes, to avoid possible OOB access in the
+      event of bugs. Fixes bug 30041; bugfix on 0.2.0.16. Found and
+      fixed by Tobias Stoeckmann.
+
+  o Minor bugfix (continuous integration):
+    - Reset coverage state on disk after Travis CI has finished. This
+      should prevent future coverage merge errors from causing the test
+      suite for the "process" subsystem to fail. The process subsystem
+      was introduced in 0.4.0.1-alpha. Fixes bug 29036; bugfix
+      on 0.2.9.15.
+    - Terminate test-stem if it takes more than 9.5 minutes to run.
+      (Travis terminates the job after 10 minutes of no output.)
+      Diagnostic for 29437. Fixes bug 30011; bugfix on 0.3.5.4-alpha.
+
+  o Minor bugfixes (bootstrap reporting):
+    - During bootstrap reporting, correctly distinguish pluggable
+      transports from plain proxies. Fixes bug 28925; bugfix
+      on 0.4.0.1-alpha.
+
+  o Minor bugfixes (C correctness):
+    - Fix an unlikely memory leak in consensus_diff_apply(). Fixes bug
+      29824; bugfix on 0.3.1.1-alpha. This is Coverity warning
+      CID 1444119.
+
+  o Minor bugfixes (circuitpadding testing):
+    - Minor tweaks to avoid rare test failures related to timers and
+      monotonic time. Fixes bug 29500; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (directory authorities):
+    - Actually include the bandwidth-file-digest line in directory
+      authority votes. Fixes bug 29959; bugfix on 0.4.0.2-alpha.
+
+  o Minor bugfixes (logging):
+    - On Windows, when errors cause us to reload a consensus from disk,
+      tell the user that we are retrying at log level "notice".
+      Previously we only logged this information at "info", which was
+      confusing because the errors themselves were logged at "warning".
+      Improves previous fix for 28614. Fixes bug 30004; bugfix
+      on 0.4.0.2-alpha.
+
+  o Minor bugfixes (pluggable transports):
+    - Restore old behavior when it comes to discovering the path of a
+      given Pluggable Transport executable file. A change in
+      0.4.0.1-alpha had broken this behavior on paths containing a
+      space. Fixes bug 29874; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (testing):
+    - Backport the 0.3.4 src/test/test-network.sh to 0.2.9. We need a
+      recent test-network.sh to use new chutney features in CI. Fixes
+      bug 29703; bugfix on 0.2.9.1-alpha.
+    - Fix a test failure on Windows caused by an unexpected "BUG"
+      warning in our tests for tor_gmtime_r(-1). Fixes bug 29922; bugfix
+      on 0.2.9.3-alpha.
+
+  o Minor bugfixes (TLS protocol):
+    - When classifying a client's selection of TLS ciphers, if the
+      client ciphers are not yet available, do not cache the result.
+      Previously, we had cached the unavailability of the cipher list
+      and never looked again, which in turn led us to assume that the
+      client only supported the ancient V1 link protocol. This, in turn,
+      was causing Stem integration tests to stall in some cases. Fixes
+      bug 30021; bugfix on 0.2.4.8-alpha.
+
+  o Code simplification and refactoring:
+    - Introduce a connection_dir_buf_add() helper function that detects
+      whether compression is in use, and adds a string accordingly.
+      Resolves issue 28816.
+    - Refactor handle_get_next_bandwidth() to use
+      connection_dir_buf_add(). Implements ticket 29897.
+
+  o Documentation:
+    - Clarify that Tor performs stream isolation among *Port listeners
+      by default. Resolves issue 29121.
+
+
+Changes in version 0.4.0.3-alpha - 2019-03-22
+  Tor 0.4.0.3-alpha is the third in its series; it fixes several small
+  bugs from earlier versions.
+
+  o Minor features (address selection):
+    - Treat the subnet 100.64.0.0/10 as public for some purposes;
+      private for others. This subnet is the RFC 6598 (Carrier Grade
+      NAT) IP range, and is deployed by many ISPs as an alternative to
+      RFC 1918 that does not break existing internal networks. Tor now
+      blocks SOCKS and control ports on these addresses and warns users
+      if client ports or ExtORPorts are listening on a RFC 6598 address.
+      Closes ticket 28525. Patch by Neel Chauhan.
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the March 4 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29666.
+
+  o Minor bugfixes (circuitpadding):
+    - Inspect the circuit-level cell queue before sending padding, to
+      avoid sending padding when too much data is queued. Fixes bug
+      29204; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (logging):
+    - Correct a misleading error message when IPv4Only or IPv6Only is
+      used but the resolved address can not be interpreted as an address
+      of the specified IP version. Fixes bug 13221; bugfix on
+      0.2.3.9-alpha. Patch from Kris Katterjohn.
+    - Log the correct port number for listening sockets when "auto" is
+      used to let Tor pick the port number. Previously, port 0 was
+      logged instead of the actual port number. Fixes bug 29144; bugfix
+      on 0.3.5.1-alpha. Patch from Kris Katterjohn.
+    - Stop logging a BUG() warning when Tor is waiting for exit
+      descriptors. Fixes bug 28656; bugfix on 0.3.5.1-alpha.
+
+  o Minor bugfixes (memory management):
+    - Refactor the shared random state's memory management so that it
+      actually takes ownership of the shared random value pointers.
+      Fixes bug 29706; bugfix on 0.2.9.1-alpha.
+
+  o Minor bugfixes (memory management, testing):
+    - Stop leaking parts of the shared random state in the shared-random
+      unit tests. Fixes bug 29599; bugfix on 0.2.9.1-alpha.
+
+  o Minor bugfixes (pluggable transports):
+    - Fix an assertion failure crash bug when a pluggable transport is
+      terminated during the bootstrap phase. Fixes bug 29562; bugfix
+      on 0.4.0.1-alpha.
+
+  o Minor bugfixes (Rust, protover):
+    - Add a missing "Padding" value to the Rust implementation of
+      protover. Fixes bug 29631; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (single onion services):
+    - Allow connections to single onion services to remain idle without
+      being disconnected. Previously, relays acting as rendezvous points
+      for single onion services were mistakenly closing idle rendezvous
+      circuits after 60 seconds, thinking that they were unused
+      directory-fetching circuits that had served their purpose. Fixes
+      bug 29665; bugfix on 0.2.1.26.
+
+  o Minor bugfixes (stats):
+    - When ExtraInfoStatistics is 0, stop including PaddingStatistics in
+      relay and bridge extra-info documents. Fixes bug 29017; bugfix
+      on 0.3.1.1-alpha.
+
+  o Minor bugfixes (testing):
+    - Downgrade some LOG_ERR messages in the address/* tests to
+      warnings. The LOG_ERR messages were occurring when we had no
+      configured network. We were failing the unit tests, because we
+      backported 28668 to 0.3.5.8, but did not backport 29530. Fixes bug
+      29530; bugfix on 0.3.5.8.
+    - Fix our gcov wrapper script to look for object files at the
+      correct locations. Fixes bug 29435; bugfix on 0.3.5.1-alpha.
+    - Decrease the false positive rate of stochastic probability
+      distribution tests. Fixes bug 29693; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (Windows, CI):
+    - Skip the Appveyor 32-bit Windows Server 2016 job, and 64-bit
+      Windows Server 2012 R2 job. The remaining 2 jobs still provide
+      coverage of 64/32-bit, and Windows Server 2016/2012 R2. Also set
+      fast_finish, so failed jobs terminate the build immediately. Fixes
+      bug 29601; bugfix on 0.3.5.4-alpha.
+
+
+Changes in version 0.3.5.8 - 2019-02-21
+  Tor 0.3.5.8 backports several fixes from later releases, including fixes
+  for an annoying SOCKS-parsing bug that affected users in earlier 0.3.5.x
+  releases.
+
+  It also includes a fix for a medium-severity security bug affecting Tor
+  0.3.2.1-alpha and later. All Tor instances running an affected release
+  should upgrade to 0.3.3.12, 0.3.4.11, 0.3.5.8, or 0.4.0.2-alpha.
+
+  o Major bugfixes (cell scheduler, KIST, security):
+    - Make KIST consider the outbuf length when computing what it can
+      put in the outbuf. Previously, KIST acted as though the outbuf
+      were empty, which could lead to the outbuf becoming too full. It
+      is possible that an attacker could exploit this bug to cause a Tor
+      client or relay to run out of memory and crash. Fixes bug 29168;
+      bugfix on 0.3.2.1-alpha. This issue is also being tracked as
+      TROVE-2019-001 and CVE-2019-8955.
+
+  o Major bugfixes (networking, backport from 0.4.0.2-alpha):
+    - Gracefully handle empty username/password fields in SOCKS5
+      username/password auth message and allow SOCKS5 handshake to
+      continue. Previously, we had rejected these handshakes, breaking
+      certain applications. Fixes bug 29175; bugfix on 0.3.5.1-alpha.
+
+  o Minor features (compilation, backport from 0.4.0.2-alpha):
+    - Compile correctly when OpenSSL is built with engine support
+      disabled, or with deprecated APIs disabled. Closes ticket 29026.
+      Patches from "Mangix".
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the February 5 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29478.
+
+  o Minor features (testing, backport from 0.4.0.2-alpha):
+    - Treat all unexpected ERR and BUG messages as test failures. Closes
+      ticket 28668.
+
+  o Minor bugfixes (onion service v3, client, backport from 0.4.0.1-alpha):
+    - Stop logging a "BUG()" warning and stacktrace when we find a SOCKS
+      connection waiting for a descriptor that we actually have in the
+      cache. It turns out that this can actually happen, though it is
+      rare. Now, tor will recover and retry the descriptor. Fixes bug
+      28669; bugfix on 0.3.2.4-alpha.
+
+  o Minor bugfixes (IPv6, backport from 0.4.0.1-alpha):
+    - Fix tor_ersatz_socketpair on IPv6-only systems. Previously, the
+      IPv6 socket was bound using an address family of AF_INET instead
+      of AF_INET6. Fixes bug 28995; bugfix on 0.3.5.1-alpha. Patch from
+      Kris Katterjohn.
+
+  o Minor bugfixes (build, compatibility, rust, backport from 0.4.0.2-alpha):
+    - Update Cargo.lock file to match the version made by the latest
+      version of Rust, so that "make distcheck" will pass again. Fixes
+      bug 29244; bugfix on 0.3.3.4-alpha.
+
+  o Minor bugfixes (client, clock skew, backport from 0.4.0.1-alpha):
+    - Select guards even if the consensus has expired, as long as the
+      consensus is still reasonably live. Fixes bug 24661; bugfix
+      on 0.3.0.1-alpha.
+
+  o Minor bugfixes (compilation, backport from 0.4.0.1-alpha):
+    - Compile correctly on OpenBSD; previously, we were missing some
+      headers required in order to detect it properly. Fixes bug 28938;
+      bugfix on 0.3.5.1-alpha. Patch from Kris Katterjohn.
+
+  o Minor bugfixes (documentation, backport from 0.4.0.2-alpha):
+    - Describe the contents of the v3 onion service client authorization
+      files correctly: They hold public keys, not private keys. Fixes
+      bug 28979; bugfix on 0.3.5.1-alpha. Spotted by "Felixix".
+
+  o Minor bugfixes (logging, backport from 0.4.0.1-alpha):
+    - Rework rep_hist_log_link_protocol_counts() to iterate through all
+      link protocol versions when logging incoming/outgoing connection
+      counts. Tor no longer skips version 5, and we won't have to
+      remember to update this function when new link protocol version is
+      developed. Fixes bug 28920; bugfix on 0.2.6.10.
+
+  o Minor bugfixes (logging, backport from 0.4.0.2-alpha):
+    - Log more information at "warning" level when unable to read a
+      private key; log more information at "info" level when unable to
+      read a public key. We had warnings here before, but they were lost
+      during our NSS work. Fixes bug 29042; bugfix on 0.3.5.1-alpha.
+
+  o Minor bugfixes (misc, backport from 0.4.0.2-alpha):
+    - The amount of total available physical memory is now determined
+      using the sysctl identifier HW_PHYSMEM (rather than HW_USERMEM)
+      when it is defined and a 64-bit variant is not available. Fixes
+      bug 28981; bugfix on 0.2.5.4-alpha. Patch from Kris Katterjohn.
+
+  o Minor bugfixes (onion services, backport from 0.4.0.2-alpha):
+    - Avoid crashing if ClientOnionAuthDir (incorrectly) contains more
+      than one private key for a hidden service. Fixes bug 29040; bugfix
+      on 0.3.5.1-alpha.
+    - In hs_cache_store_as_client() log an HSDesc we failed to parse at
+      "debug" level. Tor used to log it as a warning, which caused very
+      long log lines to appear for some users. Fixes bug 29135; bugfix
+      on 0.3.2.1-alpha.
+    - Stop logging "Tried to establish rendezvous on non-OR circuit..."
+      as a warning. Instead, log it as a protocol warning, because there
+      is nothing that relay operators can do to fix it. Fixes bug 29029;
+      bugfix on 0.2.5.7-rc.
+
+  o Minor bugfixes (tests, directory clients, backport from 0.4.0.1-alpha):
+    - Mark outdated dirservers when Tor only has a reasonably live
+      consensus. Fixes bug 28569; bugfix on 0.3.2.5-alpha.
+
+  o Minor bugfixes (tests, backport from 0.4.0.2-alpha):
+    - Detect and suppress "bug" warnings from the util/time test on
+      Windows. Fixes bug 29161; bugfix on 0.2.9.3-alpha.
+    - Do not log an error-level message if we fail to find an IPv6
+      network interface from the unit tests. Fixes bug 29160; bugfix
+      on 0.2.7.3-rc.
+
+  o Minor bugfixes (usability, backport from 0.4.0.1-alpha):
+    - Stop saying "Your Guard ..." in pathbias_measure_{use,close}_rate().
+      Some users took this phrasing to mean that the mentioned guard was
+      under their control or responsibility, which it is not. Fixes bug
+      28895; bugfix on Tor 0.3.0.1-alpha.
+
+
+Changes in version 0.3.4.11 - 2019-02-21
+  Tor 0.3.4.11 is the third stable release in its series.  It includes
+  a fix for a medium-severity security bug affecting Tor 0.3.2.1-alpha and
+  later. All Tor instances running an affected release should upgrade to
+  0.3.3.12, 0.3.4.11, 0.3.5.8, or 0.4.0.2-alpha.
+
+  o Major bugfixes (cell scheduler, KIST, security):
+    - Make KIST consider the outbuf length when computing what it can
+      put in the outbuf. Previously, KIST acted as though the outbuf
+      were empty, which could lead to the outbuf becoming too full. It
+      is possible that an attacker could exploit this bug to cause a Tor
+      client or relay to run out of memory and crash. Fixes bug 29168;
+      bugfix on 0.3.2.1-alpha. This issue is also being tracked as
+      TROVE-2019-001 and CVE-2019-8955.
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the February 5 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29478.
+
+  o Minor bugfixes (build, compatibility, rust, backport from 0.4.0.2-alpha):
+    - Update Cargo.lock file to match the version made by the latest
+      version of Rust, so that "make distcheck" will pass again. Fixes
+      bug 29244; bugfix on 0.3.3.4-alpha.
+
+  o Minor bugfixes (onion services, backport from 0.4.0.2-alpha):
+    - Stop logging "Tried to establish rendezvous on non-OR circuit..."
+      as a warning. Instead, log it as a protocol warning, because there
+      is nothing that relay operators can do to fix it. Fixes bug 29029;
+      bugfix on 0.2.5.7-rc.
+
+
+Changes in version 0.3.3.12 - 2019-02-21
+  Tor 0.3.3.12 fixes a medium-severity security bug affecting Tor
+  0.3.2.1-alpha and later. All Tor instances running an affected release
+  should upgrade to 0.3.3.12, 0.3.4.11, 0.3.5.8, or 0.4.0.2-alpha.
+
+  This release marks the end of support for the Tor 0.3.3.x series. We
+  recommend that users switch to either the Tor 0.3.4 series (supported
+  until at least 10 June 2019), or the Tor 0.3.5 series, which will
+  receive long-term support until at least 1 Feb 2022.
+
+  o Major bugfixes (cell scheduler, KIST, security):
+    - Make KIST consider the outbuf length when computing what it can
+      put in the outbuf. Previously, KIST acted as though the outbuf
+      were empty, which could lead to the outbuf becoming too full. It
+      is possible that an attacker could exploit this bug to cause a Tor
+      client or relay to run out of memory and crash. Fixes bug 29168;
+      bugfix on 0.3.2.1-alpha. This issue is also being tracked as
+      TROVE-2019-001 and CVE-2019-8955.
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the February 5 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29478.
+
+  o Minor bugfixes (build, compatibility, rust, backport from 0.4.0.2-alpha):
+    - Update Cargo.lock file to match the version made by the latest
+      version of Rust, so that "make distcheck" will pass again. Fixes
+      bug 29244; bugfix on 0.3.3.4-alpha.
+
+  o Minor bugfixes (onion services, backport from 0.4.0.2-alpha):
+    - Stop logging "Tried to establish rendezvous on non-OR circuit..."
+      as a warning. Instead, log it as a protocol warning, because there
+      is nothing that relay operators can do to fix it. Fixes bug 29029;
+      bugfix on 0.2.5.7-rc.
+
+
+Changes in version 0.4.0.2-alpha - 2019-02-21
+  Tor 0.4.0.2-alpha is the second alpha in its series; it fixes several
+  bugs from earlier versions, including several that had broken
+  backward compatibility.
+
+  It also includes a fix for a medium-severity security bug affecting Tor
+  0.3.2.1-alpha and later. All Tor instances running an affected release
+  should upgrade to 0.3.3.12, 0.3.4.11, 0.3.5.8, or 0.4.0.2-alpha.
+
+  o Major bugfixes (cell scheduler, KIST, security):
+    - Make KIST consider the outbuf length when computing what it can
+      put in the outbuf. Previously, KIST acted as though the outbuf
+      were empty, which could lead to the outbuf becoming too full. It
+      is possible that an attacker could exploit this bug to cause a Tor
+      client or relay to run out of memory and crash. Fixes bug 29168;
+      bugfix on 0.3.2.1-alpha. This issue is also being tracked as
+      TROVE-2019-001 and CVE-2019-8955.
+
+  o Major bugfixes (networking):
+    - Gracefully handle empty username/password fields in SOCKS5
+      username/password auth messsage and allow SOCKS5 handshake to
+      continue. Previously, we had rejected these handshakes, breaking
+      certain applications. Fixes bug 29175; bugfix on 0.3.5.1-alpha.
+
+  o Major bugfixes (windows, startup):
+    - When reading a consensus file from disk, detect whether it was
+      written in text mode, and re-read it in text mode if so. Always
+      write consensus files in binary mode so that we can map them into
+      memory later. Previously, we had written in text mode, which
+      confused us when we tried to map the file on windows. Fixes bug
+      28614; bugfix on 0.4.0.1-alpha.
+
+  o Minor features (compilation):
+    - Compile correctly when OpenSSL is built with engine support
+      disabled, or with deprecated APIs disabled. Closes ticket 29026.
+      Patches from "Mangix".
+
+  o Minor features (developer tooling):
+    - Check that bugfix versions in changes files look like Tor versions
+      from the versions spec. Warn when bugfixes claim to be on a future
+      release. Closes ticket 27761.
+    - Provide a git pre-commit hook that disallows committing if we have
+      any failures in our code and changelog formatting checks. It is
+      now available in scripts/maint/pre-commit.git-hook. Implements
+      feature 28976.
+
+  o Minor features (directory authority):
+    - When a directory authority is using a bandwidth file to obtain
+      bandwidth values, include the digest of that file in the vote.
+      Closes ticket 26698.
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the February 5 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29478.
+
+  o Minor features (testing):
+    - Treat all unexpected ERR and BUG messages as test failures. Closes
+      ticket 28668.
+
+  o Minor bugfixes (build, compatibility, rust):
+    - Update Cargo.lock file to match the version made by the latest
+      version of Rust, so that "make distcheck" will pass again. Fixes
+      bug 29244; bugfix on 0.3.3.4-alpha.
+
+  o Minor bugfixes (compilation):
+    - Fix compilation warnings in test_circuitpadding.c. Fixes bug
+      29169; bugfix on 0.4.0.1-alpha.
+    - Silence a compiler warning in test-memwipe.c on OpenBSD. Fixes bug
+      29145; bugfix on 0.2.9.3-alpha. Patch from Kris Katterjohn.
+
+  o Minor bugfixes (documentation):
+    - Describe the contents of the v3 onion service client authorization
+      files correctly: They hold public keys, not private keys. Fixes
+      bug 28979; bugfix on 0.3.5.1-alpha. Spotted by "Felixix".
+
+  o Minor bugfixes (linux seccomp sandbox):
+    - Fix startup crash when experimental sandbox support is enabled.
+      Fixes bug 29150; bugfix on 0.4.0.1-alpha. Patch by Peter Gerber.
+
+  o Minor bugfixes (logging):
+    - Avoid logging that we are relaxing a circuit timeout when that
+      timeout is fixed. Fixes bug 28698; bugfix on 0.2.4.7-alpha.
+    - Log more information at "warning" level when unable to read a
+      private key; log more information at "info" level when unable to
+      read a public key. We had warnings here before, but they were lost
+      during our NSS work. Fixes bug 29042; bugfix on 0.3.5.1-alpha.
+
+  o Minor bugfixes (misc):
+    - The amount of total available physical memory is now determined
+      using the sysctl identifier HW_PHYSMEM (rather than HW_USERMEM)
+      when it is defined and a 64-bit variant is not available. Fixes
+      bug 28981; bugfix on 0.2.5.4-alpha. Patch from Kris Katterjohn.
+
+  o Minor bugfixes (onion services):
+    - Avoid crashing if ClientOnionAuthDir (incorrectly) contains more
+      than one private key for a hidden service. Fixes bug 29040; bugfix
+      on 0.3.5.1-alpha.
+    - In hs_cache_store_as_client() log an HSDesc we failed to parse at
+      "debug" level. Tor used to log it as a warning, which caused very
+      long log lines to appear for some users. Fixes bug 29135; bugfix
+      on 0.3.2.1-alpha.
+    - Stop logging "Tried to establish rendezvous on non-OR circuit..."
+      as a warning. Instead, log it as a protocol warning, because there
+      is nothing that relay operators can do to fix it. Fixes bug 29029;
+      bugfix on 0.2.5.7-rc.
+
+  o Minor bugfixes (scheduler):
+    - When re-adding channels to the pending list, check the correct
+      channel's sched_heap_idx. This issue has had no effect in mainline
+      Tor, but could have led to bugs down the road in improved versions
+      of our circuit scheduling code. Fixes bug 29508; bugfix
+      on 0.3.2.10.
+
+  o Minor bugfixes (tests):
+    - Fix intermittent failures on an adaptive padding test. Fixes one
+      case of bug 29122; bugfix on 0.4.0.1-alpha.
+    - Disable an unstable circuit-padding test that was failing
+      intermittently because of an ill-defined small histogram. Such
+      histograms will be allowed again after 29298 is implemented. Fixes
+      a second case of bug 29122; bugfix on 0.4.0.1-alpha.
+    - Detect and suppress "bug" warnings from the util/time test on
+      Windows. Fixes bug 29161; bugfix on 0.2.9.3-alpha.
+    - Do not log an error-level message if we fail to find an IPv6
+      network interface from the unit tests. Fixes bug 29160; bugfix
+      on 0.2.7.3-rc.
+
+  o Documentation:
+    - In the manpage entry describing MapAddress torrc setting, use
+      example IP addresses from ranges specified for use in documentation
+      by RFC 5737. Resolves issue 28623.
+
+  o Removed features:
+    - Remove the old check-tor script. Resolves issue 29072.
+
+
 Changes in version 0.4.0.1-alpha - 2019-01-18
   Tor 0.4.0.1-alpha is the first release in the new 0.4.0.x series. It
   introduces improved features for power and bandwidth conservation,
diff --git a/Makefile.am b/Makefile.am
index 8bf2aaf91..10bd4b45c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -41,6 +41,8 @@ TOR_UTIL_LIBS = \
         src/lib/libtor-geoip.a \
 	src/lib/libtor-process.a \
         src/lib/libtor-buf.a \
+	src/lib/libtor-pubsub.a \
+	src/lib/libtor-dispatch.a \
 	src/lib/libtor-time.a \
 	src/lib/libtor-fs.a \
 	src/lib/libtor-encoding.a \
@@ -72,6 +74,8 @@ TOR_UTIL_TESTING_LIBS = \
         src/lib/libtor-geoip-testing.a \
 	src/lib/libtor-process-testing.a \
         src/lib/libtor-buf-testing.a \
+	src/lib/libtor-pubsub-testing.a \
+	src/lib/libtor-dispatch-testing.a \
 	src/lib/libtor-time-testing.a \
 	src/lib/libtor-fs-testing.a \
 	src/lib/libtor-encoding-testing.a \
@@ -161,7 +165,12 @@ EXTRA_DIST+= \
 	README						\
 	ReleaseNotes					\
 	scripts/maint/checkIncludes.py                  \
-	scripts/maint/checkSpace.pl
+	scripts/maint/checkSpace.pl 			\
+	scripts/maint/practracker/exceptions.txt	\
+	scripts/maint/practracker/metrics.py		\
+	scripts/maint/practracker/practracker.py	\
+	scripts/maint/practracker/problem.py		\
+	scripts/maint/practracker/util.py
 
 ## This tells etags how to find mockable function definitions.
 AM_ETAGSFLAGS=--regex='{c}/MOCK_IMPL([^,]+,\W*\([a-zA-Z0-9_]+\)\W*,/\1/s'
@@ -328,11 +337,8 @@ coverage-html-full: all
 	lcov --remove "$(HTML_COVER_DIR)/lcov.tmp" --rc lcov_branch_coverage=1 'test/*' 'ext/tinytest*' '/usr/*' --output-file "$(HTML_COVER_DIR)/lcov.info"
 	genhtml --branch-coverage -o "$(HTML_COVER_DIR)" "$(HTML_COVER_DIR)/lcov.info"
 
-# Avoid strlcpy.c, strlcat.c, aes.c, OpenBSD_malloc_Linux.c, sha256.c,
-# tinytest*.[ch]
-check-spaces:
-if USE_PERL
-	$(PERL) $(top_srcdir)/scripts/maint/checkSpace.pl -C \
+# For scripts: avoid src/ext and src/trunnel.
+OWNED_TOR_C_FILES=\
 		$(top_srcdir)/src/lib/*/*.[ch] \
 		$(top_srcdir)/src/core/*/*.[ch] \
 		$(top_srcdir)/src/feature/*/*.[ch] \
@@ -340,6 +346,11 @@ if USE_PERL
 		$(top_srcdir)/src/test/*.[ch] \
 		$(top_srcdir)/src/test/*/*.[ch] \
 		$(top_srcdir)/src/tools/*.[ch]
+
+check-spaces:
+if USE_PERL
+	$(PERL) $(top_srcdir)/scripts/maint/checkSpace.pl -C \
+		$(OWNED_TOR_C_FILES)
 endif
 
 check-includes:
@@ -347,6 +358,14 @@ if USEPYTHON
 	$(PYTHON) $(top_srcdir)/scripts/maint/checkIncludes.py
 endif
 
+check-best-practices:
+if USEPYTHON
+	$(PYTHON) $(top_srcdir)/scripts/maint/practracker/practracker.py $(top_srcdir)
+endif
+
+practracker-regen:
+	$(PYTHON) $(top_srcdir)/scripts/maint/practracker/practracker.py --regen $(top_srcdir)
+
 check-docs: all
 	$(PERL) $(top_builddir)/scripts/maint/checkOptionDocs.pl
 
@@ -442,6 +461,25 @@ version:
 	   (cd "$(top_srcdir)" && git rev-parse --short=16 HEAD); \
 	fi
 
+.PHONY: autostyle-ifdefs
+autostyle-ifdefs:
+	$(PYTHON) scripts/maint/annotate_ifdef_directives $(OWNED_TOR_C_FILES)
+
+.PHONY: autostyle-ifdefs
+autostyle-operators:
+	$(PERL) scripts/coccinelle/test-operator-cleanup $(OWNED_TOR_C_FILES)
+
+.PHONY: rectify-includes
+rectify-includes:
+	$(PYTHON) scripts/maint/rectify_include_paths.py
+
+.PHONY: update-copyright
+update-copyright:
+	$(PERL) scripts/maint/updateCopyright.pl $(OWNED_TOR_C_FILES)
+
+.PHONY: autostyle
+autostyle: update-versions rustfmt autostyle-ifdefs rectify-includes
+
 mostlyclean-local:
 	rm -f $(top_builddir)/src/*/*.gc{da,no} $(top_builddir)/src/*/*/*.gc{da,no}
 	rm -rf $(HTML_COVER_DIR)
diff --git a/ReleaseNotes b/ReleaseNotes
index 6c9aa3c29..788804236 100644
--- a/ReleaseNotes
+++ b/ReleaseNotes
@@ -2,6 +2,791 @@ This document summarizes new features and bugfixes in each stable
 release of Tor. If you want to see more detailed descriptions of the
 changes in each development snapshot, see the ChangeLog file.
 
+Changes in version 0.4.0.5 - 2019-05-02
+  This is the first stable release in the 0.4.0.x series. It contains
+  improvements for power management and bootstrap reporting, as well as
+  preliminary backend support for circuit padding to prevent some kinds
+  of traffic analysis. It also continues our work in refactoring Tor for
+  long-term maintainability.
+
+  Per our support policy, we will support the 0.4.0.x series for nine
+  months, or until three months after the release of a stable 0.4.1.x:
+  whichever is longer. If you need longer-term support, please stick
+  with 0.3.5.x, which will we plan to support until Feb 2022.
+
+  Below are the changes since 0.3.5.7. For a complete list of changes
+  since 0.4.0.4-rc, see the ChangeLog file.
+
+  o Major features (battery management, client, dormant mode):
+    - When Tor is running as a client, and it is unused for a long time,
+      it can now enter a "dormant" state. When Tor is dormant, it avoids
+      network and CPU activity until it is reawoken either by a user
+      request or by a controller command. For more information, see the
+      configuration options starting with "Dormant". Implements tickets
+      2149 and 28335.
+    - The client's memory of whether it is "dormant", and how long it
+      has spent idle, persists across invocations. Implements
+      ticket 28624.
+    - There is a DormantOnFirstStartup option that integrators can use
+      if they expect that in many cases, Tor will be installed but
+      not used.
+
+  o Major features (bootstrap reporting):
+    - When reporting bootstrap progress, report the first connection
+      uniformly, regardless of whether it's a connection for building
+      application circuits. This allows finer-grained reporting of early
+      progress than previously possible, with the improvements of ticket
+      27169. Closes tickets 27167 and 27103. Addresses ticket 27308.
+    - When reporting bootstrap progress, treat connecting to a proxy or
+      pluggable transport as separate from having successfully used that
+      proxy or pluggable transport to connect to a relay. Closes tickets
+      27100 and 28884.
+
+  o Major features (circuit padding):
+    - Implement preliminary support for the circuit padding portion of
+      Proposal 254. The implementation supports Adaptive Padding (aka
+      WTF-PAD) state machines for use between experimental clients and
+      relays. Support is also provided for APE-style state machines that
+      use probability distributions instead of histograms to specify
+      inter-packet delay. At the moment, Tor does not provide any
+      padding state machines that are used in normal operation: for now,
+      this feature exists solely for experimentation. Closes
+      ticket 28142.
+
+  o Major features (refactoring):
+    - Tor now uses an explicit list of its own subsystems when
+      initializing and shutting down. Previously, these systems were
+      managed implicitly in various places throughout the codebase.
+      (There may still be some subsystems using the old system.) Closes
+      ticket 28330.
+
+  o Major bugfixes (cell scheduler, KIST, security):
+    - Make KIST consider the outbuf length when computing what it can
+      put in the outbuf. Previously, KIST acted as though the outbuf
+      were empty, which could lead to the outbuf becoming too full. It
+      is possible that an attacker could exploit this bug to cause a Tor
+      client or relay to run out of memory and crash. Fixes bug 29168;
+      bugfix on 0.3.2.1-alpha. This issue is also being tracked as
+      TROVE-2019-001 and CVE-2019-8955.
+
+  o Major bugfixes (networking):
+    - Gracefully handle empty username/password fields in SOCKS5
+      username/password auth message and allow SOCKS5 handshake to
+      continue. Previously, we had rejected these handshakes, breaking
+      certain applications. Fixes bug 29175; bugfix on 0.3.5.1-alpha.
+
+  o Major bugfixes (NSS, relay):
+    - When running with NSS, disable TLS 1.2 ciphersuites that use
+      SHA384 for their PRF. Due to an NSS bug, the TLS key exporters for
+      these ciphersuites don't work -- which caused relays to fail to
+      handshake with one another when these ciphersuites were enabled.
+      Fixes bug 29241; bugfix on 0.3.5.1-alpha.
+
+  o Major bugfixes (windows, startup):
+    - When reading a consensus file from disk, detect whether it was
+      written in text mode, and re-read it in text mode if so. Always
+      write consensus files in binary mode so that we can map them into
+      memory later. Previously, we had written in text mode, which
+      confused us when we tried to map the file on windows. Fixes bug
+      28614; bugfix on 0.4.0.1-alpha.
+
+  o Minor features (address selection):
+    - Treat the subnet 100.64.0.0/10 as public for some purposes;
+      private for others. This subnet is the RFC 6598 (Carrier Grade
+      NAT) IP range, and is deployed by many ISPs as an alternative to
+      RFC 1918 that does not break existing internal networks. Tor now
+      blocks SOCKS and control ports on these addresses and warns users
+      if client ports or ExtORPorts are listening on a RFC 6598 address.
+      Closes ticket 28525. Patch by Neel Chauhan.
+
+  o Minor features (bandwidth authority):
+    - Make bandwidth authorities ignore relays that are reported in the
+      bandwidth file with the flag "vote=0". This change allows us to
+      report unmeasured relays for diagnostic reasons without including
+      their bandwidth in the bandwidth authorities' vote. Closes
+      ticket 29806.
+    - When a directory authority is using a bandwidth file to obtain the
+      bandwidth values that will be included in the next vote, serve
+      this bandwidth file at /tor/status-vote/next/bandwidth. Closes
+      ticket 21377.
+
+  o Minor features (bootstrap reporting):
+    - When reporting bootstrap progress, stop distinguishing between
+      situations where only internal paths are available and situations
+      where external paths are available. Previously, Tor would often
+      erroneously report that it had only internal paths. Closes
+      ticket 27402.
+
+  o Minor features (compilation):
+    - Compile correctly when OpenSSL is built with engine support
+      disabled, or with deprecated APIs disabled. Closes ticket 29026.
+      Patches from "Mangix".
+
+  o Minor features (continuous integration):
+    - On Travis Rust builds, cleanup Rust registry and refrain from
+      caching the "target/" directory to speed up builds. Resolves
+      issue 29962.
+    - Log Python version during each Travis CI job. Resolves
+      issue 28551.
+    - In Travis, tell timelimit to use stem's backtrace signals, and
+      launch python directly from timelimit, so python receives the
+      signals from timelimit, rather than make. Closes ticket 30117.
+
+  o Minor features (controller):
+    - Add a DROPOWNERSHIP command to undo the effects of TAKEOWNERSHIP.
+      Implements ticket 28843.
+
+  o Minor features (developer tooling):
+    - Check that bugfix versions in changes files look like Tor versions
+      from the versions spec. Warn when bugfixes claim to be on a future
+      release. Closes ticket 27761.
+    - Provide a git pre-commit hook that disallows committing if we have
+      any failures in our code and changelog formatting checks. It is
+      now available in scripts/maint/pre-commit.git-hook. Implements
+      feature 28976.
+    - Provide a git hook script to prevent "fixup!" and "squash!"
+      commits from ending up in the master branch, as scripts/main/pre-
+      push.git-hook. Closes ticket 27993.
+
+  o Minor features (diagnostic):
+    - Add more diagnostic log messages in an attempt to solve the issue
+      of NUL bytes appearing in a microdescriptor cache. Related to
+      ticket 28223.
+
+  o Minor features (directory authority):
+    - When a directory authority is using a bandwidth file to obtain
+      bandwidth values, include the digest of that file in the vote.
+      Closes ticket 26698.
+    - Directory authorities support a new consensus algorithm, under
+      which the family lines in microdescriptors are encoded in a
+      canonical form. This change makes family lines more compressible
+      in transit, and on the client. Closes ticket 28266; implements
+      proposal 298.
+
+  o Minor features (directory authority, relay):
+    - Authorities now vote on a "StaleDesc" flag to indicate that a
+      relay's descriptor is so old that the relay should upload again
+      soon. Relays treat this flag as a signal to upload a new
+      descriptor. This flag will eventually let us remove the
+      'published' date from routerstatus entries, and make our consensus
+      diffs much smaller. Closes ticket 26770; implements proposal 293.
+
+  o Minor features (dormant mode):
+    - Add a DormantCanceledByStartup option to tell Tor that it should
+      treat a startup event as cancelling any previous dormant state.
+      Integrators should use this option with caution: it should only be
+      used if Tor is being started because of something that the user
+      did, and not if Tor is being automatically started in the
+      background. Closes ticket 29357.
+
+  o Minor features (fallback directory mirrors):
+    - Update the fallback whitelist based on operator opt-ins and opt-
+      outs. Closes ticket 24805, patch by Phoul.
+
+  o Minor features (FreeBSD):
+    - On FreeBSD-based systems, warn relay operators if the
+      "net.inet.ip.random_id" sysctl (IP ID randomization) is disabled.
+      Closes ticket 28518.
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the April 2 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29992.
+
+  o Minor features (HTTP standards compliance):
+    - Stop sending the header "Content-type: application/octet-stream"
+      along with transparently compressed documents: this confused
+      browsers. Closes ticket 28100.
+
+  o Minor features (IPv6):
+    - We add an option ClientAutoIPv6ORPort, to make clients randomly
+      prefer a node's IPv4 or IPv6 ORPort. The random preference is set
+      every time a node is loaded from a new consensus or bridge config.
+      We expect that this option will enable clients to bootstrap more
+      quickly without having to determine whether they support IPv4,
+      IPv6, or both. Closes ticket 27490. Patch by Neel Chauhan.
+    - When using addrs_in_same_network_family(), avoid choosing circuit
+      paths that pass through the same IPv6 subnet more than once.
+      Previously, we only checked IPv4 subnets. Closes ticket 24393.
+      Patch by Neel Chauhan.
+
+  o Minor features (log messages):
+    - Improve log message in v3 onion services that could print out
+      negative revision counters. Closes ticket 27707. Patch
+      by "ffmancera".
+
+  o Minor features (memory usage):
+    - Save memory by storing microdescriptor family lists with a more
+      compact representation. Closes ticket 27359.
+    - Tor clients now use mmap() to read consensus files from disk, so
+      that they no longer need keep the full text of a consensus in
+      memory when parsing it or applying a diff. Closes ticket 27244.
+
+  o Minor features (NSS, diagnostic):
+    - Try to log an error from NSS (if there is any) and a more useful
+      description of our situation if we are using NSS and a call to
+      SSL_ExportKeyingMaterial() fails. Diagnostic for ticket 29241.
+
+  o Minor features (parsing):
+    - Directory authorities now validate that router descriptors and
+      ExtraInfo documents are in a valid subset of UTF-8, and reject
+      them if they are not. Closes ticket 27367.
+
+  o Minor features (performance):
+    - Cache the results of summarize_protocol_flags(), so that we don't
+      have to parse the same protocol-versions string over and over.
+      This should save us a huge number of malloc calls on startup, and
+      may reduce memory fragmentation with some allocators. Closes
+      ticket 27225.
+    - Remove a needless memset() call from get_token_arguments, thereby
+      speeding up the tokenization of directory objects by about 20%.
+      Closes ticket 28852.
+    - Replace parse_short_policy() with a faster implementation, to
+      improve microdescriptor parsing time. Closes ticket 28853.
+    - Speed up directory parsing a little by avoiding use of the non-
+      inlined strcmp_len() function. Closes ticket 28856.
+    - Speed up microdescriptor parsing by about 30%, to help improve
+      startup time. Closes ticket 28839.
+
+  o Minor features (pluggable transports):
+    - Add support for emitting STATUS updates to Tor's control port from
+      a pluggable transport process. Closes ticket 28846.
+    - Add support for logging to Tor's logging subsystem from a
+      pluggable transport process. Closes ticket 28180.
+
+  o Minor features (process management):
+    - Add a new process API for handling child processes. This new API
+      allows Tor to have bi-directional communication with child
+      processes on both Unix and Windows. Closes ticket 28179.
+    - Use the subsystem manager to initialize and shut down the process
+      module. Closes ticket 28847.
+
+  o Minor features (relay):
+    - When listing relay families, list them in canonical form including
+      the relay's own identity, and try to give a more useful set of
+      warnings. Part of ticket 28266 and proposal 298.
+
+  o Minor features (required protocols):
+    - Before exiting because of a missing required protocol, Tor will
+      now check the publication time of the consensus, and not exit
+      unless the consensus is newer than the Tor program's own release
+      date. Previously, Tor would not check the consensus publication
+      time, and so might exit because of a missing protocol that might
+      no longer be required in a current consensus. Implements proposal
+      297; closes ticket 27735.
+
+  o Minor features (testing):
+    - Treat all unexpected ERR and BUG messages as test failures. Closes
+      ticket 28668.
+    - Allow a HeartbeatPeriod of less than 30 minutes in testing Tor
+      networks. Closes ticket 28840. Patch by Rob Jansen.
+    - Use the approx_time() function when setting the "Expires" header
+      in directory replies, to make them more testable. Needed for
+      ticket 30001.
+
+  o Minor bugfixes (security):
+    - Fix a potential double free bug when reading huge bandwidth files.
+      The issue is not exploitable in the current Tor network because
+      the vulnerable code is only reached when directory authorities
+      read bandwidth files, but bandwidth files come from a trusted
+      source (usually the authorities themselves). Furthermore, the
+      issue is only exploitable in rare (non-POSIX) 32-bit architectures,
+      which are not used by any of the current authorities. Fixes bug
+      30040; bugfix on 0.3.5.1-alpha. Bug found and fixed by
+      Tobias Stoeckmann.
+    - Verify in more places that we are not about to create a buffer
+      with more than INT_MAX bytes, to avoid possible OOB access in the
+      event of bugs. Fixes bug 30041; bugfix on 0.2.0.16. Found and
+      fixed by Tobias Stoeckmann.
+
+  o Minor bugfix (continuous integration):
+    - Reset coverage state on disk after Travis CI has finished. This
+      should prevent future coverage merge errors from causing the test
+      suite for the "process" subsystem to fail. The process subsystem
+      was introduced in 0.4.0.1-alpha. Fixes bug 29036; bugfix
+      on 0.2.9.15.
+    - Terminate test-stem if it takes more than 9.5 minutes to run.
+      (Travis terminates the job after 10 minutes of no output.)
+      Diagnostic for 29437. Fixes bug 30011; bugfix on 0.3.5.4-alpha.
+
+  o Minor bugfixes (build, compatibility, rust):
+    - Update Cargo.lock file to match the version made by the latest
+      version of Rust, so that "make distcheck" will pass again. Fixes
+      bug 29244; bugfix on 0.3.3.4-alpha.
+
+  o Minor bugfixes (C correctness):
+    - Fix an unlikely memory leak in consensus_diff_apply(). Fixes bug
+      29824; bugfix on 0.3.1.1-alpha. This is Coverity warning
+      CID 1444119.
+
+  o Minor bugfixes (client, clock skew):
+    - Bootstrap successfully even when Tor's clock is behind the clocks
+      on the authorities. Fixes bug 28591; bugfix on 0.2.0.9-alpha.
+    - Select guards even if the consensus has expired, as long as the
+      consensus is still reasonably live. Fixes bug 24661; bugfix
+      on 0.3.0.1-alpha.
+
+  o Minor bugfixes (compilation):
+    - Fix compilation warnings in test_circuitpadding.c. Fixes bug
+      29169; bugfix on 0.4.0.1-alpha.
+    - Silence a compiler warning in test-memwipe.c on OpenBSD. Fixes bug
+      29145; bugfix on 0.2.9.3-alpha. Patch from Kris Katterjohn.
+    - Compile correctly on OpenBSD; previously, we were missing some
+      headers required in order to detect it properly. Fixes bug 28938;
+      bugfix on 0.3.5.1-alpha. Patch from Kris Katterjohn.
+
+  o Minor bugfixes (directory clients):
+    - Mark outdated dirservers when Tor only has a reasonably live
+      consensus. Fixes bug 28569; bugfix on 0.3.2.5-alpha.
+
+  o Minor bugfixes (directory mirrors):
+    - Even when a directory mirror's clock is behind the clocks on the
+      authorities, we now allow the mirror to serve "future"
+      consensuses. Fixes bug 28654; bugfix on 0.3.0.1-alpha.
+
+  o Minor bugfixes (DNS):
+    - Gracefully handle an empty or absent resolve.conf file by falling
+      back to using "localhost" as a DNS server (and hoping it works).
+      Previously, we would just stop running as an exit. Fixes bug
+      21900; bugfix on 0.2.1.10-alpha.
+
+  o Minor bugfixes (documentation):
+    - Describe the contents of the v3 onion service client authorization
+      files correctly: They hold public keys, not private keys. Fixes
+      bug 28979; bugfix on 0.3.5.1-alpha. Spotted by "Felixix".
+
+  o Minor bugfixes (guards):
+    - In count_acceptable_nodes(), the minimum number is now one bridge
+      or guard node, and two non-guard nodes for a circuit. Previously,
+      we had added up the sum of all nodes with a descriptor, but that
+      could cause us to build failing circuits when we had either too
+      many bridges or not enough guard nodes. Fixes bug 25885; bugfix on
+      0.3.6.1-alpha. Patch by Neel Chauhan.
+
+  o Minor bugfixes (IPv6):
+    - Fix tor_ersatz_socketpair on IPv6-only systems. Previously, the
+      IPv6 socket was bound using an address family of AF_INET instead
+      of AF_INET6. Fixes bug 28995; bugfix on 0.3.5.1-alpha. Patch from
+      Kris Katterjohn.
+
+  o Minor bugfixes (linux seccomp sandbox):
+    - Fix startup crash when experimental sandbox support is enabled.
+      Fixes bug 29150; bugfix on 0.4.0.1-alpha. Patch by Peter Gerber.
+
+  o Minor bugfixes (logging):
+    - Correct a misleading error message when IPv4Only or IPv6Only is
+      used but the resolved address can not be interpreted as an address
+      of the specified IP version. Fixes bug 13221; bugfix on
+      0.2.3.9-alpha. Patch from Kris Katterjohn.
+    - Log the correct port number for listening sockets when "auto" is
+      used to let Tor pick the port number. Previously, port 0 was
+      logged instead of the actual port number. Fixes bug 29144; bugfix
+      on 0.3.5.1-alpha. Patch from Kris Katterjohn.
+    - Stop logging a BUG() warning when Tor is waiting for exit
+      descriptors. Fixes bug 28656; bugfix on 0.3.5.1-alpha.
+    - Avoid logging that we are relaxing a circuit timeout when that
+      timeout is fixed. Fixes bug 28698; bugfix on 0.2.4.7-alpha.
+    - Log more information at "warning" level when unable to read a
+      private key; log more information at "info" level when unable to
+      read a public key. We had warnings here before, but they were lost
+      during our NSS work. Fixes bug 29042; bugfix on 0.3.5.1-alpha.
+    - Rework rep_hist_log_link_protocol_counts() to iterate through all
+      link protocol versions when logging incoming/outgoing connection
+      counts. Tor no longer skips version 5, and we won't have to
+      remember to update this function when new link protocol version is
+      developed. Fixes bug 28920; bugfix on 0.2.6.10.
+
+  o Minor bugfixes (memory management):
+    - Refactor the shared random state's memory management so that it
+      actually takes ownership of the shared random value pointers.
+      Fixes bug 29706; bugfix on 0.2.9.1-alpha.
+    - Stop leaking parts of the shared random state in the shared-random
+      unit tests. Fixes bug 29599; bugfix on 0.2.9.1-alpha.
+
+  o Minor bugfixes (misc):
+    - The amount of total available physical memory is now determined
+      using the sysctl identifier HW_PHYSMEM (rather than HW_USERMEM)
+      when it is defined and a 64-bit variant is not available. Fixes
+      bug 28981; bugfix on 0.2.5.4-alpha. Patch from Kris Katterjohn.
+
+  o Minor bugfixes (networking):
+    - Introduce additional checks into tor_addr_parse() to reject
+      certain incorrect inputs that previously were not detected. Fixes
+      bug 23082; bugfix on 0.2.0.10-alpha.
+
+  o Minor bugfixes (onion service v3, client):
+    - Stop logging a "BUG()" warning and stacktrace when we find a SOCKS
+      connection waiting for a descriptor that we actually have in the
+      cache. It turns out that this can actually happen, though it is
+      rare. Now, tor will recover and retry the descriptor. Fixes bug
+      28669; bugfix on 0.3.2.4-alpha.
+
+  o Minor bugfixes (onion services):
+    - Avoid crashing if ClientOnionAuthDir (incorrectly) contains more
+      than one private key for a hidden service. Fixes bug 29040; bugfix
+      on 0.3.5.1-alpha.
+    - In hs_cache_store_as_client() log an HSDesc we failed to parse at
+      "debug" level. Tor used to log it as a warning, which caused very
+      long log lines to appear for some users. Fixes bug 29135; bugfix
+      on 0.3.2.1-alpha.
+    - Stop logging "Tried to establish rendezvous on non-OR circuit..."
+      as a warning. Instead, log it as a protocol warning, because there
+      is nothing that relay operators can do to fix it. Fixes bug 29029;
+      bugfix on 0.2.5.7-rc.
+
+  o Minor bugfixes (periodic events):
+    - Refrain from calling routerlist_remove_old_routers() from
+      check_descriptor_callback(). Instead, create a new hourly periodic
+      event. Fixes bug 27929; bugfix on 0.2.8.1-alpha.
+
+  o Minor bugfixes (pluggable transports):
+    - Make sure that data is continously read from standard output and
+      standard error pipes of a pluggable transport child-process, to
+      avoid deadlocking when a pipe's buffer is full. Fixes bug 26360;
+      bugfix on 0.2.3.6-alpha.
+
+  o Minor bugfixes (rust):
+    - Abort on panic in all build profiles, instead of potentially
+      unwinding into C code. Fixes bug 27199; bugfix on 0.3.3.1-alpha.
+
+  o Minor bugfixes (scheduler):
+    - When re-adding channels to the pending list, check the correct
+      channel's sched_heap_idx. This issue has had no effect in mainline
+      Tor, but could have led to bugs down the road in improved versions
+      of our circuit scheduling code. Fixes bug 29508; bugfix
+      on 0.3.2.10.
+
+  o Minor bugfixes (shellcheck):
+    - Look for scripts in their correct locations during "make
+      shellcheck". Previously we had looked in the wrong place during
+      out-of-tree builds. Fixes bug 30263; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (single onion services):
+    - Allow connections to single onion services to remain idle without
+      being disconnected. Previously, relays acting as rendezvous points
+      for single onion services were mistakenly closing idle rendezvous
+      circuits after 60 seconds, thinking that they were unused
+      directory-fetching circuits that had served their purpose. Fixes
+      bug 29665; bugfix on 0.2.1.26.
+
+  o Minor bugfixes (stats):
+    - When ExtraInfoStatistics is 0, stop including PaddingStatistics in
+      relay and bridge extra-info documents. Fixes bug 29017; bugfix
+      on 0.3.1.1-alpha.
+
+  o Minor bugfixes (testing):
+    - Backport the 0.3.4 src/test/test-network.sh to 0.2.9. We need a
+      recent test-network.sh to use new chutney features in CI. Fixes
+      bug 29703; bugfix on 0.2.9.1-alpha.
+    - Fix a test failure on Windows caused by an unexpected "BUG"
+      warning in our tests for tor_gmtime_r(-1). Fixes bug 29922; bugfix
+      on 0.2.9.3-alpha.
+    - Downgrade some LOG_ERR messages in the address/* tests to
+      warnings. The LOG_ERR messages were occurring when we had no
+      configured network. We were failing the unit tests, because we
+      backported 28668 to 0.3.5.8, but did not backport 29530. Fixes bug
+      29530; bugfix on 0.3.5.8.
+    - Fix our gcov wrapper script to look for object files at the
+      correct locations. Fixes bug 29435; bugfix on 0.3.5.1-alpha.
+    - Decrease the false positive rate of stochastic probability
+      distribution tests. Fixes bug 29693; bugfix on 0.4.0.1-alpha.
+    - Fix intermittent failures on an adaptive padding test. Fixes one
+      case of bug 29122; bugfix on 0.4.0.1-alpha.
+    - Disable an unstable circuit-padding test that was failing
+      intermittently because of an ill-defined small histogram. Such
+      histograms will be allowed again after 29298 is implemented. Fixes
+      a second case of bug 29122; bugfix on 0.4.0.1-alpha.
+    - Detect and suppress "bug" warnings from the util/time test on
+      Windows. Fixes bug 29161; bugfix on 0.2.9.3-alpha.
+    - Do not log an error-level message if we fail to find an IPv6
+      network interface from the unit tests. Fixes bug 29160; bugfix
+      on 0.2.7.3-rc.
+    - Instead of relying on hs_free_all() to clean up all onion service
+      objects in test_build_descriptors(), we now deallocate them one by
+      one. This lets Coverity know that we are not leaking memory there
+      and fixes CID 1442277. Fixes bug 28989; bugfix on 0.3.5.1-alpha.
+    - Check the time in the "Expires" header using approx_time(). Fixes
+      bug 30001; bugfix on 0.4.0.4-rc.
+
+  o Minor bugfixes (TLS protocol):
+    - When classifying a client's selection of TLS ciphers, if the
+      client ciphers are not yet available, do not cache the result.
+      Previously, we had cached the unavailability of the cipher list
+      and never looked again, which in turn led us to assume that the
+      client only supported the ancient V1 link protocol. This, in turn,
+      was causing Stem integration tests to stall in some cases. Fixes
+      bug 30021; bugfix on 0.2.4.8-alpha.
+
+  o Minor bugfixes (UI):
+    - Lower log level of unlink() errors during bootstrap. Fixes bug
+      29930; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (usability):
+    - Stop saying "Your Guard ..." in pathbias_measure_{use,close}_rate().
+      Some users took this phrasing to mean that the mentioned guard was
+      under their control or responsibility, which it is not. Fixes bug
+      28895; bugfix on Tor 0.3.0.1-alpha.
+
+  o Minor bugfixes (Windows, CI):
+    - Skip the Appveyor 32-bit Windows Server 2016 job, and 64-bit
+      Windows Server 2012 R2 job. The remaining 2 jobs still provide
+      coverage of 64/32-bit, and Windows Server 2016/2012 R2. Also set
+      fast_finish, so failed jobs terminate the build immediately. Fixes
+      bug 29601; bugfix on 0.3.5.4-alpha.
+
+  o Code simplification and refactoring:
+    - Introduce a connection_dir_buf_add() helper function that detects
+      whether compression is in use, and adds a string accordingly.
+      Resolves issue 28816.
+    - Refactor handle_get_next_bandwidth() to use
+      connection_dir_buf_add(). Implements ticket 29897.
+    - Reimplement NETINFO cell parsing and generation to rely on
+      trunnel-generated wire format handling code. Closes ticket 27325.
+    - Remove unnecessary unsafe code from the Rust macro "cstr!". Closes
+      ticket 28077.
+    - Rework SOCKS wire format handling to rely on trunnel-generated
+      parsing/generation code. Resolves ticket 27620.
+    - Split out bootstrap progress reporting from control.c into a
+      separate file. Part of ticket 27402.
+    - The .may_include files that we use to describe our directory-by-
+      directory dependency structure now describe a noncircular
+      dependency graph over the directories that they cover. Our
+      checkIncludes.py tool now enforces this noncircularity. Closes
+      ticket 28362.
+
+  o Documentation:
+    - Clarify that Tor performs stream isolation among *Port listeners
+      by default. Resolves issue 29121.
+    - In the manpage entry describing MapAddress torrc setting, use
+      example IP addresses from ranges specified for use in documentation
+      by RFC 5737. Resolves issue 28623.
+    - Mention that you cannot add a new onion service if Tor is already
+      running with Sandbox enabled. Closes ticket 28560.
+    - Improve ControlPort documentation. Mention that it accepts
+      address:port pairs, and can be used multiple times. Closes
+      ticket 28805.
+    - Document the exact output of "tor --version". Closes ticket 28889.
+
+  o Removed features:
+    - Remove the old check-tor script. Resolves issue 29072.
+    - Stop responding to the 'GETINFO status/version/num-concurring' and
+      'GETINFO status/version/num-versioning' control port commands, as
+      those were deprecated back in 0.2.0.30. Also stop listing them in
+      output of 'GETINFO info/names'. Resolves ticket 28757.
+    - The scripts used to generate and maintain the list of fallback
+      directories have been extracted into a new "fallback-scripts"
+      repository. Closes ticket 27914.
+
+  o Testing:
+    - Run shellcheck for scripts in the in scripts/ directory. Closes
+      ticket 28058.
+    - Add unit tests for tokenize_string() and get_next_token()
+      functions. Resolves ticket 27625.
+
+  o Code simplification and refactoring (onion service v3):
+    - Consolidate the authorized client descriptor cookie computation
+      code from client and service into one function. Closes
+      ticket 27549.
+
+  o Code simplification and refactoring (shell scripts):
+    - Cleanup scan-build.sh to silence shellcheck warnings. Closes
+      ticket 28007.
+    - Fix issues that shellcheck found in chutney-git-bisect.sh.
+      Resolves ticket 28006.
+    - Fix issues that shellcheck found in updateRustDependencies.sh.
+      Resolves ticket 28012.
+    - Fix shellcheck warnings in cov-diff script. Resolves issue 28009.
+    - Fix shellcheck warnings in run_calltool.sh. Resolves ticket 28011.
+    - Fix shellcheck warnings in run_trunnel.sh. Resolves issue 28010.
+    - Fix shellcheck warnings in scripts/test/coverage. Resolves
+      issue 28008.
+
+
+Changes in version 0.3.5.8 - 2019-02-21
+  Tor 0.3.5.8 backports several fixes from later releases, including fixes
+  for an annoying SOCKS-parsing bug that affected users in earlier 0.3.5.x
+  releases.
+
+  It also includes a fix for a medium-severity security bug affecting Tor
+  0.3.2.1-alpha and later. All Tor instances running an affected release
+  should upgrade to 0.3.3.12, 0.3.4.11, 0.3.5.8, or 0.4.0.2-alpha.
+
+  o Major bugfixes (cell scheduler, KIST, security):
+    - Make KIST consider the outbuf length when computing what it can
+      put in the outbuf. Previously, KIST acted as though the outbuf
+      were empty, which could lead to the outbuf becoming too full. It
+      is possible that an attacker could exploit this bug to cause a Tor
+      client or relay to run out of memory and crash. Fixes bug 29168;
+      bugfix on 0.3.2.1-alpha. This issue is also being tracked as
+      TROVE-2019-001 and CVE-2019-8955.
+
+  o Major bugfixes (networking, backport from 0.4.0.2-alpha):
+    - Gracefully handle empty username/password fields in SOCKS5
+      username/password auth messsage and allow SOCKS5 handshake to
+      continue. Previously, we had rejected these handshakes, breaking
+      certain applications. Fixes bug 29175; bugfix on 0.3.5.1-alpha.
+
+  o Minor features (compilation, backport from 0.4.0.2-alpha):
+    - Compile correctly when OpenSSL is built with engine support
+      disabled, or with deprecated APIs disabled. Closes ticket 29026.
+      Patches from "Mangix".
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the February 5 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29478.
+
+  o Minor features (testing, backport from 0.4.0.2-alpha):
+    - Treat all unexpected ERR and BUG messages as test failures. Closes
+      ticket 28668.
+
+  o Minor bugfixes (onion service v3, client, backport from 0.4.0.1-alpha):
+    - Stop logging a "BUG()" warning and stacktrace when we find a SOCKS
+      connection waiting for a descriptor that we actually have in the
+      cache. It turns out that this can actually happen, though it is
+      rare. Now, tor will recover and retry the descriptor. Fixes bug
+      28669; bugfix on 0.3.2.4-alpha.
+
+  o Minor bugfixes (IPv6, backport from 0.4.0.1-alpha):
+    - Fix tor_ersatz_socketpair on IPv6-only systems. Previously, the
+      IPv6 socket was bound using an address family of AF_INET instead
+      of AF_INET6. Fixes bug 28995; bugfix on 0.3.5.1-alpha. Patch from
+      Kris Katterjohn.
+
+  o Minor bugfixes (build, compatibility, rust, backport from 0.4.0.2-alpha):
+    - Update Cargo.lock file to match the version made by the latest
+      version of Rust, so that "make distcheck" will pass again. Fixes
+      bug 29244; bugfix on 0.3.3.4-alpha.
+
+  o Minor bugfixes (client, clock skew, backport from 0.4.0.1-alpha):
+    - Select guards even if the consensus has expired, as long as the
+      consensus is still reasonably live. Fixes bug 24661; bugfix
+      on 0.3.0.1-alpha.
+
+  o Minor bugfixes (compilation, backport from 0.4.0.1-alpha):
+    - Compile correctly on OpenBSD; previously, we were missing some
+      headers required in order to detect it properly. Fixes bug 28938;
+      bugfix on 0.3.5.1-alpha. Patch from Kris Katterjohn.
+
+  o Minor bugfixes (documentation, backport from 0.4.0.2-alpha):
+    - Describe the contents of the v3 onion service client authorization
+      files correctly: They hold public keys, not private keys. Fixes
+      bug 28979; bugfix on 0.3.5.1-alpha. Spotted by "Felixix".
+
+  o Minor bugfixes (logging, backport from 0.4.0.1-alpha):
+    - Rework rep_hist_log_link_protocol_counts() to iterate through all
+      link protocol versions when logging incoming/outgoing connection
+      counts. Tor no longer skips version 5, and we won't have to
+      remember to update this function when new link protocol version is
+      developed. Fixes bug 28920; bugfix on 0.2.6.10.
+
+  o Minor bugfixes (logging, backport from 0.4.0.2-alpha):
+    - Log more information at "warning" level when unable to read a
+      private key; log more information at "info" level when unable to
+      read a public key. We had warnings here before, but they were lost
+      during our NSS work. Fixes bug 29042; bugfix on 0.3.5.1-alpha.
+
+  o Minor bugfixes (misc, backport from 0.4.0.2-alpha):
+    - The amount of total available physical memory is now determined
+      using the sysctl identifier HW_PHYSMEM (rather than HW_USERMEM)
+      when it is defined and a 64-bit variant is not available. Fixes
+      bug 28981; bugfix on 0.2.5.4-alpha. Patch from Kris Katterjohn.
+
+  o Minor bugfixes (onion services, backport from 0.4.0.2-alpha):
+    - Avoid crashing if ClientOnionAuthDir (incorrectly) contains more
+      than one private key for a hidden service. Fixes bug 29040; bugfix
+      on 0.3.5.1-alpha.
+    - In hs_cache_store_as_client() log an HSDesc we failed to parse at
+      "debug" level. Tor used to log it as a warning, which caused very
+      long log lines to appear for some users. Fixes bug 29135; bugfix
+      on 0.3.2.1-alpha.
+    - Stop logging "Tried to establish rendezvous on non-OR circuit..."
+      as a warning. Instead, log it as a protocol warning, because there
+      is nothing that relay operators can do to fix it. Fixes bug 29029;
+      bugfix on 0.2.5.7-rc.
+
+  o Minor bugfixes (tests, directory clients, backport from 0.4.0.1-alpha):
+    - Mark outdated dirservers when Tor only has a reasonably live
+      consensus. Fixes bug 28569; bugfix on 0.3.2.5-alpha.
+
+  o Minor bugfixes (tests, backport from 0.4.0.2-alpha):
+    - Detect and suppress "bug" warnings from the util/time test on
+      Windows. Fixes bug 29161; bugfix on 0.2.9.3-alpha.
+    - Do not log an error-level message if we fail to find an IPv6
+      network interface from the unit tests. Fixes bug 29160; bugfix
+      on 0.2.7.3-rc.
+
+  o Minor bugfixes (usability, backport from 0.4.0.1-alpha):
+    - Stop saying "Your Guard ..." in pathbias_measure_{use,close}_rate().
+      Some users took this phrasing to mean that the mentioned guard was
+      under their control or responsibility, which it is not. Fixes bug
+      28895; bugfix on Tor 0.3.0.1-alpha.
+
+
+Changes in version 0.3.4.11 - 2019-02-21
+  Tor 0.3.4.11 is the third stable release in its series.  It includes
+  a fix for a medium-severity security bug affecting Tor 0.3.2.1-alpha and
+  later. All Tor instances running an affected release should upgrade to
+  0.3.3.12, 0.3.4.11, 0.3.5.8, or 0.4.0.2-alpha.
+
+  o Major bugfixes (cell scheduler, KIST, security):
+    - Make KIST consider the outbuf length when computing what it can
+      put in the outbuf. Previously, KIST acted as though the outbuf
+      were empty, which could lead to the outbuf becoming too full. It
+      is possible that an attacker could exploit this bug to cause a Tor
+      client or relay to run out of memory and crash. Fixes bug 29168;
+      bugfix on 0.3.2.1-alpha. This issue is also being tracked as
+      TROVE-2019-001 and CVE-2019-8955.
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the February 5 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29478.
+
+  o Minor bugfixes (build, compatibility, rust, backport from 0.4.0.2-alpha):
+    - Update Cargo.lock file to match the version made by the latest
+      version of Rust, so that "make distcheck" will pass again. Fixes
+      bug 29244; bugfix on 0.3.3.4-alpha.
+
+  o Minor bugfixes (onion services, backport from 0.4.0.2-alpha):
+    - Stop logging "Tried to establish rendezvous on non-OR circuit..."
+      as a warning. Instead, log it as a protocol warning, because there
+      is nothing that relay operators can do to fix it. Fixes bug 29029;
+      bugfix on 0.2.5.7-rc.
+
+
+Changes in version 0.3.3.12 - 2019-02-21
+  Tor 0.3.3.12 fixes a medium-severity security bug affecting Tor
+  0.3.2.1-alpha and later. All Tor instances running an affected release
+  should upgrade to 0.3.3.12, 0.3.4.11, 0.3.5.8, or 0.4.0.2-alpha.
+
+  This release marks the end of support for the Tor 0.3.3.x series. We
+  recommend that users switch to either the Tor 0.3.4 series (supported
+  until at least 10 June 2019), or the Tor 0.3.5 series, which will
+  receive long-term support until at least 1 Feb 2022.
+
+  o Major bugfixes (cell scheduler, KIST, security):
+    - Make KIST consider the outbuf length when computing what it can
+      put in the outbuf. Previously, KIST acted as though the outbuf
+      were empty, which could lead to the outbuf becoming too full. It
+      is possible that an attacker could exploit this bug to cause a Tor
+      client or relay to run out of memory and crash. Fixes bug 29168;
+      bugfix on 0.3.2.1-alpha. This issue is also being tracked as
+      TROVE-2019-001 and CVE-2019-8955.
+
+  o Minor features (geoip):
+    - Update geoip and geoip6 to the February 5 2019 Maxmind GeoLite2
+      Country database. Closes ticket 29478.
+
+  o Minor bugfixes (build, compatibility, rust, backport from 0.4.0.2-alpha):
+    - Update Cargo.lock file to match the version made by the latest
+      version of Rust, so that "make distcheck" will pass again. Fixes
+      bug 29244; bugfix on 0.3.3.4-alpha.
+
+  o Minor bugfixes (onion services, backport from 0.4.0.2-alpha):
+    - Stop logging "Tried to establish rendezvous on non-OR circuit..."
+      as a warning. Instead, log it as a protocol warning, because there
+      is nothing that relay operators can do to fix it. Fixes bug 29029;
+      bugfix on 0.2.5.7-rc.
+
+
 Changes in version 0.3.3.11 - 2019-01-07
   Tor 0.3.3.11 backports numerous fixes from later versions of Tor.
   numerous fixes, including an important fix for anyone using OpenSSL
diff --git a/autogen.sh b/autogen.sh
index 276dd4047..63ef6d49e 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -1,9 +1,9 @@
 #!/bin/sh
 
-if [ -x "`which autoreconf 2>/dev/null`" ] ; then
+if command -v autoreconf; then
   opt="-i -f -W all,error"
 
-  for i in $@; do
+  for i in "$@"; do
     case "$i" in
       -v)
         opt="${opt} -v"
@@ -11,6 +11,7 @@ if [ -x "`which autoreconf 2>/dev/null`" ] ; then
     esac
   done
 
+  # shellcheck disable=SC2086
   exec autoreconf $opt
 fi
 
diff --git a/changes/29241_diagnostic b/changes/29241_diagnostic
deleted file mode 100644
index 1e3865495..000000000
--- a/changes/29241_diagnostic
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (NSS, diagnostic):
-    - Try to log an error from NSS (if there is any) and a more useful
-      description of our situation if we are using NSS and a call to
-      SSL_ExportKeyingMaterial() fails.  Diagnostic for ticket 29241.
diff --git a/changes/bug13221 b/changes/bug13221
deleted file mode 100644
index 13935a192..000000000
--- a/changes/bug13221
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfixes (logging):
-    - Correct a misleading error message when IPv4Only or IPv6Only
-      is used but the resolved address can not be interpreted as an
-      address of the specified IP version.  Fixes bug 13221; bugfix
-      on 0.2.3.9-alpha.  Patch from Kris Katterjohn.
diff --git a/changes/bug22619 b/changes/bug22619
new file mode 100644
index 000000000..9c71996f5
--- /dev/null
+++ b/changes/bug22619
@@ -0,0 +1,3 @@
+  o Minor bugfixes (circuit isolation):
+    - Fix a logic error that prevented the SessionGroup sub-option from
+      being accepted. Fixes bug 22619; bugfix on 0.2.7.2-alpha.
diff --git a/changes/bug23507 b/changes/bug23507
new file mode 100644
index 000000000..de18273fd
--- /dev/null
+++ b/changes/bug23507
@@ -0,0 +1,5 @@
+  o Minor bugfixes (v3 single onion services):
+    - Make v3 single onion services fall back to a 3-hop intro, when there
+      all intro points are unreachable via a 1-hop path. Previously, v3
+      single onion services failed when all intro nodes were unreachable
+      via a 1-hop path. Fixes bug 23507; bugfix on 0.3.2.1-alpha.
diff --git a/changes/bug23818_v2 b/changes/bug23818_v2
new file mode 100644
index 000000000..0219a20f4
--- /dev/null
+++ b/changes/bug23818_v2
@@ -0,0 +1,6 @@
+  o Minor bugfixes (v2 single onion services):
+    - Always retry v2 single onion service intro and rend circuits with a
+      3-hop path. Previously, v2 single onion services used a 3-hop path
+      when rend circuits were retried after a remote or delayed failure,
+      but a 1-hop path for immediate retries. Fixes bug 23818;
+      bugfix on 0.2.9.3-alpha.
diff --git a/changes/bug23818_v3 b/changes/bug23818_v3
new file mode 100644
index 000000000..c430144d8
--- /dev/null
+++ b/changes/bug23818_v3
@@ -0,0 +1,6 @@
+  o Minor bugfixes (v3 single onion services):
+    - Always retry v3 single onion service intro and rend circuits with a
+      3-hop path. Previously, v3 single onion services used a 3-hop path
+      when rend circuits were retried after a remote or delayed failure,
+      but a 1-hop path for immediate retries. Fixes bug 23818;
+      bugfix on 0.3.2.1-alpha.
diff --git a/changes/bug27199 b/changes/bug27199
deleted file mode 100644
index f9d2a422f..000000000
--- a/changes/bug27199
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (rust):
-    - Abort on panic in all build profiles, instead of potentially unwinding
-      into C code. Fixes bug 27199; bugfix on 0.3.3.1-alpha.
diff --git a/changes/bug28525 b/changes/bug28525
deleted file mode 100644
index 988ffb219..000000000
--- a/changes/bug28525
+++ /dev/null
@@ -1,7 +0,0 @@
-  o Minor features (address selection):
-    - Make Tor aware of the RFC 6598 (Carrier Grade NAT) IP range, which is the
-      subnet 100.64.0.0/10. This is deployed by many ISPs as an alternative to
-      RFC 1918 that does not break existing internal networks. This patch fixes
-      security issues caused by RFC 6518 by blocking control ports on these
-      addresses and warns users if client ports or ExtORPorts are listening on
-      a RFC 6598 address. Closes ticket 28525. Patch by Neel Chauhan.
diff --git a/changes/bug28614_better_logging b/changes/bug28614_better_logging
deleted file mode 100644
index 26d19c3c1..000000000
--- a/changes/bug28614_better_logging
+++ /dev/null
@@ -1,6 +0,0 @@
-  o Minor bugfixes (logging):
-    - On Windows, when errors cause us to reload a consensus from disk, tell
-      the user that we are retrying at log level "notice". Previously we only
-      logged this information at "info", which was confusing because the
-      errors themselves were logged at "warning". Improves previous fix for
-      28614.  Fixes bug 30004; bugfix on 0.4.0.2-alpha.
diff --git a/changes/bug28656 b/changes/bug28656
deleted file mode 100644
index d3a13d196..000000000
--- a/changes/bug28656
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (logging):
-    - Stop logging a BUG() warning when tor is waiting for exit descriptors.
-      Fixes bug 28656; bugfix on 0.3.5.1-alpha.
diff --git a/changes/bug28698 b/changes/bug28698
deleted file mode 100644
index 716aa0c55..000000000
--- a/changes/bug28698
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfix (logging):
-    - Avoid logging about relaxing circuits when their time is fixed.
-      Fixes bug 28698; bugfix on 0.2.4.7-alpha
diff --git a/changes/bug28925 b/changes/bug28925
deleted file mode 100644
index a86744388..000000000
--- a/changes/bug28925
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (bootstrap reporting):
-    - During bootstrap reporting, correctly distinguish pluggable
-      transports from plain proxies. Fixes bug 28925; bugfix on
-      0.4.0.1-alpha.
diff --git a/changes/bug28979 b/changes/bug28979
deleted file mode 100644
index 0625fd5d2..000000000
--- a/changes/bug28979
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (documentation):
-    - Describe the contents of the v3 onion service client authorization
-      files correctly: They hold public keys, not private keys. Fixes bug
-      28979; bugfix on 0.3.5.1-alpha. Spotted by "Felixix".
diff --git a/changes/bug28981 b/changes/bug28981
deleted file mode 100644
index c0ea92ab3..000000000
--- a/changes/bug28981
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfixes (misc):
-    - The amount of total available physical memory is now determined
-      using the sysctl identifier HW_PHYSMEM (rather than HW_USERMEM)
-      when it is defined and a 64-bit variant is not available.  Fixes
-      bug 28981; bugfix on 0.2.5.4-alpha.  Patch from Kris Katterjohn.
diff --git a/changes/bug29017 b/changes/bug29017
deleted file mode 100644
index 5c4a53c43..000000000
--- a/changes/bug29017
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (stats):
-    - When ExtraInfoStatistics is 0, stop including PaddingStatistics in
-      relay and bridge extra-info documents. Fixes bug 29017;
-      bugfix on 0.3.1.1-alpha.
diff --git a/changes/bug29029 b/changes/bug29029
deleted file mode 100644
index e100a8c2e..000000000
--- a/changes/bug29029
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfixes (logging, onion services):
-    - Stop logging "Tried to establish rendezvous on non-OR circuit..." as
-      a warning. Instead, log it as a protocol warning, because there is
-      nothing that relay operators can do to fix it. Fixes bug 29029;
-      bugfix on 0.2.5.7-rc.
diff --git a/changes/bug29034 b/changes/bug29034
new file mode 100644
index 000000000..e7aa9af00
--- /dev/null
+++ b/changes/bug29034
@@ -0,0 +1,5 @@
+  o Major bugfixes (Onion service reachability):
+    - Properly clean up the introduction point map when circuits change purpose
+      from onion service circuits to pathbias, measurement, or other circuit types.
+      This should fix some service-side instances of introduction point failure.
+      Fixes bug 29034; bugfix on 0.3.2.1-alpha.
diff --git a/changes/bug29036 b/changes/bug29036
deleted file mode 100644
index 8b96c5c8f..000000000
--- a/changes/bug29036
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfix (continuous integration):
-    - Reset coverage state on disk after Travis CI has finished. This is being
-      done to prevent future gcda file merge errors which causes the test suite
-      for the process subsystem to fail. The process subsystem was introduced
-      in 0.4.0.1-alpha. Fixes bug 29036; bugfix on 0.2.9.15.
diff --git a/changes/bug29040 b/changes/bug29040
deleted file mode 100644
index 0662aaa8a..000000000
--- a/changes/bug29040
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (onion services):
-    - Avoid crashing if ClientOnionAuthDir (incorrectly) contains
-      more than one private key for a hidden service. Fixes bug 29040;
-      bugfix on 0.3.5.1-alpha.
diff --git a/changes/bug29042 b/changes/bug29042
deleted file mode 100644
index 8d76939ce..000000000
--- a/changes/bug29042
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfixes (logging):
-    - Log more information at "warning" level when unable to read a private
-      key; log more information ad "info" level when unable to read a public
-      key. We had warnings here before, but they were lost during our
-      NSS work. Fixes bug 29042; bugfix on 0.3.5.1-alpha.
diff --git a/changes/bug29122 b/changes/bug29122
deleted file mode 100644
index 020052ff8..000000000
--- a/changes/bug29122
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (unit tests):
-    - Fix intermittent failures on an adaptive padding unittest. Fixes bug
-      29122; bugfix on 0.4.0.1-alpha
diff --git a/changes/bug29135 b/changes/bug29135
deleted file mode 100644
index fd7b1ae80..000000000
--- a/changes/bug29135
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfixes (onion services, logging):
-    - In hs_cache_store_as_client() log an HSDesc we failed to parse at Debug
-      loglevel. Tor used to log it at Warning loglevel, which caused
-      very long log lines to appear for some users. Fixes bug 29135; bugfix on
-      0.3.2.1-alpha.
diff --git a/changes/bug29144 b/changes/bug29144
deleted file mode 100644
index 5801224f1..000000000
--- a/changes/bug29144
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfixes (logging):
-    - Log the correct port number for listening sockets when "auto" is
-      used to let Tor pick the port number.  Previously, port 0 was
-      logged instead of the actual port number.  Fixes bug 29144;
-      bugfix on 0.3.5.1-alpha.  Patch from Kris Katterjohn.
diff --git a/changes/bug29145 b/changes/bug29145
deleted file mode 100644
index 40d3da4b9..000000000
--- a/changes/bug29145
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (compilation, testing):
-    - Silence a compiler warning in test-memwipe.c on OpenBSD.  Fixes
-      bug 29145; bugfix on 0.2.9.3-alpha.  Patch from Kris Katterjohn.
diff --git a/changes/bug29150 b/changes/bug29150
deleted file mode 100644
index 7696b9037..000000000
--- a/changes/bug29150
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (linux seccomp sandbox):
-    - Fix startup crash when experimental sandbox support is enabled.
-      Fixes bug 29150; bugfix on 0.4.0.1-alpha. Patch by Peter Gerber.
diff --git a/changes/bug29161 b/changes/bug29161
deleted file mode 100644
index 39a638acf..000000000
--- a/changes/bug29161
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (tests):
-    - Detect and suppress "bug" warnings from the util/time test on Windows.
-      Fixes bug 29161; bugfix on 0.2.9.3-alpha.
diff --git a/changes/bug29169 b/changes/bug29169
deleted file mode 100644
index 41d4b76ef..000000000
--- a/changes/bug29169
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (compilation):
-    - Fix compilation warnings in test_circuitpadding.c.  Fixes bug 29169;
-      bugfix on 0.4.0.1-alpha.
diff --git a/changes/bug29175_035 b/changes/bug29175_035
deleted file mode 100644
index 134c1d952..000000000
--- a/changes/bug29175_035
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Major bugfixes (networking):
-    - Gracefully handle empty username/password fields in SOCKS5
-      username/password auth messsage and allow SOCKS5 handshake to
-      continue. Fixes bug 29175; bugfix on 0.3.5.1-alpha.
diff --git a/changes/bug29204 b/changes/bug29204
deleted file mode 100644
index ec2cf67b2..000000000
--- a/changes/bug29204
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (circuitpadding):
-    - Inspect circuit-level cell queue before sending padding, to avoid
-      sending padding while too much data is queued. Fixes bug 29204;
-      bugfix on 0.4.0.1-alpha.
diff --git a/changes/bug29241 b/changes/bug29241
deleted file mode 100644
index 7f25e154d..000000000
--- a/changes/bug29241
+++ /dev/null
@@ -1,6 +0,0 @@
-  o Major bugfixes (NSS, relay):
-    - When running with NSS, disable TLS 1.2 ciphersuites that use SHA384
-      for their PRF. Due to an NSS bug, the TLS key exporters for these
-      ciphersuites don't work -- which caused relays to fail to handshake
-      with one another when these ciphersuites were enabled.
-      Fixes bug 29241; bugfix on 0.3.5.1-alpha.
diff --git a/changes/bug29244 b/changes/bug29244
deleted file mode 100644
index 6206a9546..000000000
--- a/changes/bug29244
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (build, compatibility):
-    - Update Cargo.lock file to match the version made by the latest
-      version of Rust, so that "make distcheck" will pass again.
-      Fixes bug 29244; bugfix on 0.3.3.4-alpha.
diff --git a/changes/bug29298 b/changes/bug29298
deleted file mode 100644
index df12db77d..000000000
--- a/changes/bug29298
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfixes (testing, circuit padding):
-    - Disabled unstable circuit padding unittest that was causing intermittent
-      test failures because of ill-defined small histogram. Such histograms
-      will be allowed again after 29298 is implemented. Fixes second case of
-      bug 29122; bugfix on 0.4.0.1-alpha.
\ No newline at end of file
diff --git a/changes/bug29500 b/changes/bug29500
deleted file mode 100644
index 16550935b..000000000
--- a/changes/bug29500
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (circuitpadding testing):
-    - Minor tweaks to avoid very rare test failures related to timers and
-      monotime. Fixes bug 29500; bugfix on 0.4.0.1-alpha
diff --git a/changes/bug29508 b/changes/bug29508
deleted file mode 100644
index ee728bbbc..000000000
--- a/changes/bug29508
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (scheduler):
-    - When readding channels to the pending list, check the correct channel's
-      sched_heap_idx. Fixes bug 29508; bugfix on 0.3.2.10
diff --git a/changes/bug29527 b/changes/bug29527
deleted file mode 100644
index 6f36a9e1a..000000000
--- a/changes/bug29527
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor features (circuit padding):
-    - Stop warning about undefined behavior in the probability distribution
-      tests. Float division by zero may technically be undefined behaviour in
-      C, but it's well-defined in IEEE 754. Partial backport of 29298.
-      Closes ticket 29527; bugfix on 0.4.0.1-alpha.
diff --git a/changes/bug29530_035 b/changes/bug29530_035
deleted file mode 100644
index 6dfcd51e7..000000000
--- a/changes/bug29530_035
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfixes (testing):
-    - Downgrade some LOG_ERR messages in the address/* tests to warnings.
-      The LOG_ERR messages were occurring when we had no configured network.
-      We were failing the unit tests, because we backported 28668 to 0.3.5.8,
-      but did not backport 29530. Fixes bug 29530; bugfix on 0.3.5.8.
diff --git a/changes/bug29562 b/changes/bug29562
deleted file mode 100644
index 0621cd09a..000000000
--- a/changes/bug29562
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (pluggable transports):
-    - Fix an assertion failure crash bug when a pluggable transport process is
-      terminated during the bootstrap phase. Fixes bug 29562; bugfix on
-      0.4.0.1-alpha.
diff --git a/changes/bug29599 b/changes/bug29599
deleted file mode 100644
index 14e2f5d07..000000000
--- a/changes/bug29599
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (memory management, testing):
-    - Stop leaking parts of the shared random state in the shared-random unit
-      tests. Fixes bug 29599; bugfix on 0.2.9.1-alpha.
diff --git a/changes/bug29601 b/changes/bug29601
deleted file mode 100644
index c4ba5fbc8..000000000
--- a/changes/bug29601
+++ /dev/null
@@ -1,6 +0,0 @@
-  o Minor bugfixes (Windows, CI):
-    - Skip the Appveyor 32-bit Windows Server 2016 job, and 64-bit Windows
-      Server 2012 R2 job. The remaining 2 jobs still provide coverage of
-      64/32-bit, and Windows Server 2016/2012 R2. Also set fast_finish, so
-      failed jobs terminate the build immediately.
-      Fixes bug 29601; bugfix on 0.3.5.4-alpha.
diff --git a/changes/bug29665 b/changes/bug29665
deleted file mode 100644
index d89046faf..000000000
--- a/changes/bug29665
+++ /dev/null
@@ -1,7 +0,0 @@
-  o Minor bugfixes (single onion services):
-    - Allow connections to single onion services to remain idle without
-      being disconnected. Relays acting as rendezvous points for
-      single onion services were mistakenly closing idle established
-      rendezvous circuits after 60 seconds, thinking that they are unused
-      directory-fetching circuits that had served their purpose. Fixes
-      bug 29665; bugfix on 0.2.1.26.
diff --git a/changes/bug29693 b/changes/bug29693
deleted file mode 100644
index 33ce051c4..000000000
--- a/changes/bug29693
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (unit tests):
-    - Decrease the false positive rate of stochastic probability distribution
-      tests. Fixes bug 29693; bugfix on 0.4.0.1-alpha.
\ No newline at end of file
diff --git a/changes/bug29703 b/changes/bug29703
deleted file mode 100644
index 0e17ee45e..000000000
--- a/changes/bug29703
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (testing):
-    - Backport the 0.3.4 src/test/test-network.sh to 0.2.9.
-      We need a recent test-network.sh to use new chutney features in CI.
-      Fixes bug 29703; bugfix on 0.2.9.1-alpha.
diff --git a/changes/bug29706_minimal b/changes/bug29706_minimal
deleted file mode 100644
index 9d4a43326..000000000
--- a/changes/bug29706_minimal
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (memory management, testing):
-    - Stop leaking parts of the shared random state in the shared-random unit
-      tests. The previous fix in 29599 was incomplete.
-      Fixes bug 29706; bugfix on 0.2.9.1-alpha.
diff --git a/changes/bug29706_refactor b/changes/bug29706_refactor
deleted file mode 100644
index ba1d0c7ed..000000000
--- a/changes/bug29706_refactor
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (memory management):
-    - Refactor the shared random state's memory management so that it actually
-      takes ownership of the shared random value pointers.
-      Fixes bug 29706; bugfix on 0.2.9.1-alpha.
diff --git a/changes/bug29874 b/changes/bug29874
deleted file mode 100644
index 8534753b5..000000000
--- a/changes/bug29874
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (pluggable transports):
-    - Restore old behaviour when it comes to discovering the path of a given
-      Pluggable Transport exe-file. Fixes bug 29874; bugfix on 0.4.0.1-alpha.
-
diff --git a/changes/bug29922 b/changes/bug29922
deleted file mode 100644
index dacb95109..000000000
--- a/changes/bug29922
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (testing, windows):
-    - Fix a test failure caused by an unexpected bug warning in
-      our test for tor_gmtime_r(-1). Fixes bug 29922;
-      bugfix on 0.2.9.3-alpha.
diff --git a/changes/bug29930 b/changes/bug29930
deleted file mode 100644
index a99b11430..000000000
--- a/changes/bug29930
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (UI):
-    - Lower log level of unlink() errors during bootstrap. Fixes bug 29930;
-      bugfix on 0.4.0.1-alpha.
-
diff --git a/changes/bug29959-040 b/changes/bug29959-040
deleted file mode 100644
index 3740e0169..000000000
--- a/changes/bug29959-040
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (directory authorities):
-    - Actually include the bandwidth-file-digest line in directory authority
-      votes. Fixes bug 29959; bugfix on 0.4.0.2-alpha.
diff --git a/changes/bug30001 b/changes/bug30001
deleted file mode 100644
index 52e58872e..000000000
--- a/changes/bug30001
+++ /dev/null
@@ -1,7 +0,0 @@
-  o Minor features (testing):
-    - Use the approx_time() function when setting the "Expires" header
-      in directory replies, to make them more testable. Needed for
-      ticket 30001.
-  o Minor bug fixes (testing):
-    - Check the time in the "Expires" header with approx_time().
-      Fixes bug 30001; bugfix on 0.4.0.4-rc.
diff --git a/changes/bug30011 b/changes/bug30011
deleted file mode 100644
index 4c9069e29..000000000
--- a/changes/bug30011
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (CI):
-    - Terminate test-stem if it takes more than 9.5 minutes to run.
-      (Travis terminates the job after 10 minutes of no output.)
-      Diagnostic for 29437. Fixes bug 30011; bugfix on 0.3.5.4-alpha.
diff --git a/changes/bug30021 b/changes/bug30021
deleted file mode 100644
index 2a887f3cf..000000000
--- a/changes/bug30021
+++ /dev/null
@@ -1,8 +0,0 @@
-  o Minor bugfixes (TLS protocol, integration tests):
-    - When classifying a client's selection of TLS ciphers, if the client
-      ciphers are not yet available, do not cache the result. Previously,
-      we had cached the unavailability of the cipher list and never looked
-      again, which in turn led us to assume that the client only supported
-      the ancient V1 link protocol.  This, in turn, was causing Stem
-      integration tests to stall in some cases.
-      Fixes bug 30021; bugfix on 0.2.4.8-alpha.
diff --git a/changes/bug30040 b/changes/bug30040
deleted file mode 100644
index 7d80528a1..000000000
--- a/changes/bug30040
+++ /dev/null
@@ -1,9 +0,0 @@
-  o Minor bugfixes (security):
-    - Fix a potential double free bug when reading huge bandwidth files. The
-      issue is not exploitable in the current Tor network because the
-      vulnerable code is only reached when directory authorities read bandwidth
-      files, but bandwidth files come from a trusted source (usually the
-      authorities themselves). Furthermore, the issue is only exploitable in
-      rare (non-POSIX) 32-bit architectures which are not used by any of the
-      current authorities. Fixes bug 30040; bugfix on 0.3.5.1-alpha. Bug found
-      and fixed by Tobias Stoeckmann.
diff --git a/changes/bug30041 b/changes/bug30041
deleted file mode 100644
index 801c8f67a..000000000
--- a/changes/bug30041
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Minor bugfixes (hardening):
-    - Verify in more places that we are not about to create a buffer
-      with more than INT_MAX bytes, to avoid possible OOB access in the event
-      of bugs.  Fixes bug 30041; bugfix on 0.2.0.16.  Found and fixed by
-      Tobias Stoeckmann.
diff --git a/changes/bug30189 b/changes/bug30189
deleted file mode 100644
index f8c932a5f..000000000
--- a/changes/bug30189
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (compilation, unusual configuration):
-    - Avoid failures when building with ALL_BUGS_ARE_FAILED due to
-      missing declarations of abort(), and prevent other such failures
-      in the future. Fixes bug 30189; bugfix on 0.3.4.1-alpha.
diff --git a/changes/bug30263 b/changes/bug30263
deleted file mode 100644
index ba81c1b8a..000000000
--- a/changes/bug30263
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (shellcheck):
-    - Stop looking for scripts in the build directory during
-      "make shellcheck". Fixes bug 30263; bugfix on 0.4.0.1-alpha.
diff --git a/changes/bug30316 b/changes/bug30316
deleted file mode 100644
index 3e396318a..000000000
--- a/changes/bug30316
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (directory authority):
-    - Move the "bandwidth-file-headers" line in directory authority votes
-      so that it conforms to dir-spec.txt. Fixes bug 30316; bugfix on
-      0.3.5.1-alpha.
diff --git a/changes/bug30452 b/changes/bug30452
deleted file mode 100644
index 2bb401d87..000000000
--- a/changes/bug30452
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor features (compile-time modules):
-    - Add a --list-modules command to print a list of which compile-time
-      modules are enabled. Closes ticket 30452.
diff --git a/changes/bug30475 b/changes/bug30475
deleted file mode 100644
index 839597b88..000000000
--- a/changes/bug30475
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes ():
-    - Avoid a GCC 9.1.1 warning (and possible crash depending on libc
-      implemenation) when failing to load a hidden service client authorization
-      file.  Fixes bug 30475; bugfix on 0.3.5.1-alpha.
diff --git a/changes/bug30781 b/changes/bug30781
new file mode 100644
index 000000000..7c7adf470
--- /dev/null
+++ b/changes/bug30781
@@ -0,0 +1,4 @@
+  o Minor bugfixes (directory authorities):
+    - Stop crashing after parsing an unknown descriptor purpose annotation.
+      We think this bug can only be triggered by modifying a local file.
+      Fixes bug 30781; bugfix on 0.2.0.8-alpha.
diff --git a/changes/bug30894 b/changes/bug30894
new file mode 100644
index 000000000..64c14c4e6
--- /dev/null
+++ b/changes/bug30894
@@ -0,0 +1,4 @@
+  o Minor bugfixes (memory leaks):
+    - Fix a trivial memory leak when parsing an invalid value
+      from a download schedule in the configuration. Fixes bug
+      30894; bugfix on 0.3.4.1-alpha.
diff --git a/changes/bug30942 b/changes/bug30942
new file mode 100644
index 000000000..bd6b2ff58
--- /dev/null
+++ b/changes/bug30942
@@ -0,0 +1,4 @@
+  o Minor bugfixes (circuit padding):
+    - Ignore non-padding cells on padding circuits. This addresses various
+      warning messages from subsystems that were not expecting padding
+      circuits. Fixes bug 30942; bugfix on 0.4.1.1-alpha.
\ No newline at end of file
diff --git a/changes/bug30956 b/changes/bug30956
new file mode 100644
index 000000000..8f52a81de
--- /dev/null
+++ b/changes/bug30956
@@ -0,0 +1,4 @@
+  o Minor bugfixes (pluggable transports):
+    - Always publish bridge pluggable transport information in the extra info
+      descriptor, even if ExtraInfoStatistics is 0. This information is
+      needed by BridgeDB. Fixes bug 30956; bugfix on 0.4.1.1-alpha.
diff --git a/changes/bug31003 b/changes/bug31003
new file mode 100644
index 000000000..6c7516338
--- /dev/null
+++ b/changes/bug31003
@@ -0,0 +1,4 @@
+  o Minor bugfixes (crash on exit):
+    - Avoid a set of possible code paths that could use try to use freed memory
+      in routerlist_free() while Tor was exiting.  Fixes bug 31003; bugfix on
+      0.1.2.2-alpha.
diff --git a/changes/bug31024 b/changes/bug31024
new file mode 100644
index 000000000..888fb2a26
--- /dev/null
+++ b/changes/bug31024
@@ -0,0 +1,4 @@
+  o Minor bugfixes (circuitpadding):
+    - Add two NULL checks in unreachable places to silence Coverity (CID 144729
+      and 1447291) and better future proof ourselves. Fixes bug 31024; bugfix
+      on 0.4.1.1-alpha.
\ No newline at end of file
diff --git a/changes/bug31027 b/changes/bug31027
new file mode 100644
index 000000000..dd3ce20b6
--- /dev/null
+++ b/changes/bug31027
@@ -0,0 +1,3 @@
+  o Code simplification and refactoring:
+    - Remove some dead code from circpad_machine_remove_token() to fix some
+      Coverity warnings (CID 1447298). Fixes bug 31027; bugfix on 0.4.1.1-alpha.
\ No newline at end of file
diff --git a/changes/bug31080_041 b/changes/bug31080_041
new file mode 100644
index 000000000..1fe9ec508
--- /dev/null
+++ b/changes/bug31080_041
@@ -0,0 +1,4 @@
+  o Minor bugfixes (logging):
+    - Fix a conflict between the flag used for messaging-domain
+      log messages, and the LD_NO_MOCK testing flag. Fixes bug 31080;
+      bugfix on 0.4.1.1-alpha.
diff --git a/changes/bug31343 b/changes/bug31343
new file mode 100644
index 000000000..17a8057ea
--- /dev/null
+++ b/changes/bug31343
@@ -0,0 +1,9 @@
+  o Minor bugfixes (compilation):
+    - Avoid using labs() on time_t, which can cause compilation warnings
+      on 64-bit Windows builds.  Fixes bug 31343; bugfix on 0.2.4.4-alpha.
+
+  o Minor bugfixes (clock skew detection):
+    - Don't believe clock skew results from NETINFO cells that appear to
+      arrive before the VERSIONS cells they are responding to were sent.
+      Previously, we would accept them up to 3 minutes "in the past".
+      Fixes bug 31343; bugfix on 0.2.4.4-alpha.
diff --git a/changes/bug31356_and_logs b/changes/bug31356_and_logs
new file mode 100644
index 000000000..fb5307cb6
--- /dev/null
+++ b/changes/bug31356_and_logs
@@ -0,0 +1,11 @@
+  o Minor bugfixes (circuit padding negotiation):
+    - Bump circuit padding protover to explicitly signify that the hs setup
+      machine support is finalized in 0.4.1.x-stable. This also means that
+      0.4.1.x-alpha clients will not negotiate padding with 0.4.1.x-stable
+      relays, and 0.4.1.x-stable clients will not negotiate padding with
+      0.4.1.x-alpha relays (or 0.4.0.x relays). Fixes bug 31356;
+      bugfix on 0.4.1.1-alpha.
+  o Minor features (circuit padding logging):
+    - Demote noisy client-side warn log to a protocol warning. Add additional
+      log messages and circuit id fields to help with fixing bug 30992 and any
+      other future issues.
diff --git a/changes/bug31463 b/changes/bug31463
new file mode 100644
index 000000000..d85c0887c
--- /dev/null
+++ b/changes/bug31463
@@ -0,0 +1,3 @@
+  o Minor bugfixes (rust):
+    - Correctly exclude a redundant rust build job in Travis. Fixes bug 31463;
+      bugfix on 0.3.5.4-alpha.
diff --git a/changes/chutney_ci b/changes/chutney_ci
new file mode 100644
index 000000000..b17d58732
--- /dev/null
+++ b/changes/chutney_ci
@@ -0,0 +1,3 @@
+  o Minor features (continuous integration):
+    - Our Travis configuration now uses Chutney to run some network
+      integration tests automatically. Closes ticket 29280.
diff --git a/changes/cid1444119 b/changes/cid1444119
deleted file mode 100644
index bb6854e66..000000000
--- a/changes/cid1444119
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (C correctness):
-    - Fix an unlikely memory leak in consensus_diff_apply(). Fixes bug 29824;
-      bugfix on 0.3.1.1-alpha. This is Coverity warning CID 1444119.
diff --git a/changes/diagnostic_28223_redux b/changes/diagnostic_28223_redux
deleted file mode 100644
index 0d7499832..000000000
--- a/changes/diagnostic_28223_redux
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (diagnostic):
-    - Add more diagnostic log messages in an attempt to solve
-      the issue of NUL bytes appearing in a microdescriptor cache.
-      Related to ticket 28223.
diff --git a/changes/doc28623 b/changes/doc28623
deleted file mode 100644
index 3c3313abd..000000000
--- a/changes/doc28623
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Documentation:
-    - In manpage entry describing MapAddress torrc setting, use example
-      IP addresses from ranges specified by RFC 5737. Resolves issue 28623.
diff --git a/changes/doc29121 b/changes/doc29121
deleted file mode 100644
index dd31cc9c7..000000000
--- a/changes/doc29121
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Documentation:
-    - Clarify that Tor performs stream isolation between *Port listeners by
-      default. Resolves issue 29121.
diff --git a/changes/doc30630 b/changes/doc30630
new file mode 100644
index 000000000..0fbd8d4dd
--- /dev/null
+++ b/changes/doc30630
@@ -0,0 +1,3 @@
+  o Documentation:
+    - Mention URLs for Travis/Appveyor/Jenkins in ReleasingTor.md. Closes
+      ticket 30630.
diff --git a/changes/feature28976 b/changes/feature28976
deleted file mode 100644
index c7ebc207f..000000000
--- a/changes/feature28976
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (developer tooling):
-    - Provide a git pre-commit hook that disallows commiting if we have any
-      failures in our code and changelog formatting checks. It is now available
-      in scripts/maint/pre-commit.git-hook. Implements feature 28976.
diff --git a/changes/geoip-2019-02-05 b/changes/geoip-2019-02-05
deleted file mode 100644
index 78ee6d424..000000000
--- a/changes/geoip-2019-02-05
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (geoip):
-    - Update geoip and geoip6 to the February 5 2019 Maxmind GeoLite2
-      Country database. Closes ticket 29478.
-
diff --git a/changes/geoip-2019-03-04 b/changes/geoip-2019-03-04
deleted file mode 100644
index c8ce5dad5..000000000
--- a/changes/geoip-2019-03-04
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (geoip):
-    - Update geoip and geoip6 to the March 4 2019 Maxmind GeoLite2
-      Country database. Closes ticket 29666.
-
diff --git a/changes/geoip-2019-04-02 b/changes/geoip-2019-04-02
deleted file mode 100644
index 7302d939f..000000000
--- a/changes/geoip-2019-04-02
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (geoip):
-    - Update geoip and geoip6 to the April 2 2019 Maxmind GeoLite2
-      Country database. Closes ticket 29992.
-
diff --git a/changes/geoip-2019-05-13 b/changes/geoip-2019-05-13
deleted file mode 100644
index 0a2fa1897..000000000
--- a/changes/geoip-2019-05-13
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (geoip):
-    - Update geoip and geoip6 to the May 13 2019 Maxmind GeoLite2
-      Country database. Closes ticket 30522.
-
diff --git a/changes/ticket21377 b/changes/ticket21377
deleted file mode 100644
index 2bf5149a0..000000000
--- a/changes/ticket21377
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (dircache):
-    - When a directory authority is using a bandwidth file to obtain the
-      bandwidth values that will be included in the next vote, serve this
-      bandwidth file at /tor/status-vote/next/bandwidth. Closes ticket 21377.
\ No newline at end of file
diff --git a/changes/ticket26698 b/changes/ticket26698
deleted file mode 100644
index 6b029a1b7..000000000
--- a/changes/ticket26698
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (directory authority):
-    - When a directory authority is using a bandwidth file to obtain the
-      bandwidth values, include the digest of the file in the vote.
-      Closes ticket 26698.
diff --git a/changes/ticket27761 b/changes/ticket27761
deleted file mode 100644
index 35106ee9c..000000000
--- a/changes/ticket27761
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (changelogs):
-    - Check that bugfix versions in changes files look like Tor versions
-      from the versions spec. Warn when bugfixes claim to be on a future
-      release. Closes ticket 27761.
diff --git a/changes/ticket28614 b/changes/ticket28614
deleted file mode 100644
index 3c9331372..000000000
--- a/changes/ticket28614
+++ /dev/null
@@ -1,8 +0,0 @@
-  o Major bugfixes (windows, startup):
-    - When writing a consensus file to disk, always write in
-      "binary" mode so that we can safely map it into memory later.
-      Fixes part of bug 28614; bugfix on 0.4.0.1-alpha.
-    - When reading a consensus file from disk, detect whether it
-      was written in text mode, and re-read it in text mode if so.
-      Fixes part of bug 28614; bugfix on 0.4.0.1-alpha.
-
diff --git a/changes/ticket28668 b/changes/ticket28668
deleted file mode 100644
index 6386e0051..000000000
--- a/changes/ticket28668
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor features (testing):
-    - Treat all unexpected ERR and BUG messages as test failures.
-      Closes ticket 28668.
diff --git a/changes/ticket28816 b/changes/ticket28816
deleted file mode 100644
index 02878ccfd..000000000
--- a/changes/ticket28816
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Code simplification and refactoring:
-    - Introduce a connection_dir_buf_add() helper function that checks for
-      compress_state of dir_connection_t and automatically writes a string to
-      directory connection with or without compression. Resolves issue 28816.
diff --git a/changes/ticket29026 b/changes/ticket29026
deleted file mode 100644
index 1db873dfc..000000000
--- a/changes/ticket29026
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor features (compilation):
-    - Compile correctly when OpenSSL is built with engine support
-      disabled, or with deprecated APIs disabled. Closes ticket
-      29026. Patches from "Mangix".
diff --git a/changes/ticket29072 b/changes/ticket29072
deleted file mode 100644
index 3526330f3..000000000
--- a/changes/ticket29072
+++ /dev/null
@@ -1,2 +0,0 @@
-  o Removed features:
-    - Remove check-tor script from repository. Resolves issue 29072.
diff --git a/changes/ticket29160 b/changes/ticket29160
deleted file mode 100644
index 8e1118306..000000000
--- a/changes/ticket29160
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (tests):
-    - Do not log an error-level message if we fail to find an IPv6
-      network interface from the unit tests. Fixes bug 29160; bugfix on
-      0.2.7.3-rc.
diff --git a/changes/ticket29168 b/changes/ticket29168
deleted file mode 100644
index 65c5232f6..000000000
--- a/changes/ticket29168
+++ /dev/null
@@ -1,5 +0,0 @@
-  o Major bugfixes (cell scheduler, KIST):
-    - Make KIST to always take into account the outbuf length when computing
-      what we can actually put in the outbuf. This could lead to the outbuf
-      being filled up and thus a possible memory DoS vector. TROVE-2019-001.
-      Fixes bug 29168; bugfix on 0.3.2.1-alpha.
diff --git a/changes/ticket29357 b/changes/ticket29357
deleted file mode 100644
index 3aab930cd..000000000
--- a/changes/ticket29357
+++ /dev/null
@@ -1,7 +0,0 @@
-  o Minor features (dormant mode):
-    - Add a DormantCanceledByStartup option to tell Tor that it should
-      treat a startup event as cancelling any previous dormant state.
-      Integrators should use this option with caution: it should
-      only be used if Tor is being started because of something that the
-      user did, and not if Tor is being automatically started in the
-      background. Closes ticket 29357.
diff --git a/changes/ticket29435 b/changes/ticket29435
deleted file mode 100644
index d48ae98e4..000000000
--- a/changes/ticket29435
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor bugfixes (testing):
-    - Fix our gcov wrapper script to look for object files at the
-      correct locations. Fixes bug 29435; bugfix on 0.3.5.1-alpha.
diff --git a/changes/ticket29631 b/changes/ticket29631
deleted file mode 100644
index 9fc194ba9..000000000
--- a/changes/ticket29631
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Minor bugfixes (Rust, protover):
-    - The Rust implementation of protover was missing the "Padding" value in
-      the translate function from C to Rust. Fixes bug 29631; bugfix on
-      0.4.0.1-alpha.
diff --git a/changes/ticket29702 b/changes/ticket29702
deleted file mode 100644
index e1cc1f867..000000000
--- a/changes/ticket29702
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Testing:
-    - Specify torrc paths (with empty files) when launching tor in
-      integration tests; refrain from reading user and system torrcs.
-      Resolves issue 29702.
diff --git a/changes/ticket29806 b/changes/ticket29806
deleted file mode 100644
index 6afefd4c0..000000000
--- a/changes/ticket29806
+++ /dev/null
@@ -1,7 +0,0 @@
-  o Minor features (bandwidth authority):
-    - Make bandwidth authorities to ignore relays that are reported in the
-      bandwidth file with the key-value "vote=0".
-      This change allows to report the relays that were not measured due
-      some failure and diagnose the reasons without the bandwidth being included in the
-      bandwidth authorities vote.
-      Closes ticket 29806.
diff --git a/changes/ticket29897 b/changes/ticket29897
deleted file mode 100644
index 232a79fbc..000000000
--- a/changes/ticket29897
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Code simplification and refactoring:
-    - Refactor handle_get_next_bandwidth() to use connection_dir_buf_add().
-      Implements ticket 29897.
diff --git a/changes/ticket29962 b/changes/ticket29962
deleted file mode 100644
index e36cc0cf9..000000000
--- a/changes/ticket29962
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor features (continuous integration):
-    - On Travis Rust builds, cleanup Rust registry and refrain from caching
-      target/ directory to speed up builds. Resolves issue 29962.
diff --git a/changes/ticket30117 b/changes/ticket30117
deleted file mode 100644
index 5b6e6dabf..000000000
--- a/changes/ticket30117
+++ /dev/null
@@ -1,4 +0,0 @@
-  o Testing (continuous integration):
-    - In Travis, tell timelimit to use stem's backtrace signals. And launch
-      python directly from timelimit, so python receives the signals from
-      timelimit, rather than make. Closes ticket 30117.
diff --git a/changes/ticket30213 b/changes/ticket30213
deleted file mode 100644
index acb761480..000000000
--- a/changes/ticket30213
+++ /dev/null
@@ -1,3 +0,0 @@
-  o Minor features (continuous integration):
-    - Remove sudo configuration lines from .travis.yml as they are no longer
-      needed with current Travis build environment. Resolves issue 30213.
diff --git a/changes/ticket30234 b/changes/ticket30234
deleted file mode 100644
index 5a0076bad..000000000
--- a/changes/ticket30234
+++ /dev/null
@@ -1,2 +0,0 @@
-  o Testing (continuous integration):
-    - In Travis, show stem's tor log after failure. Closes ticket 30234.
diff --git a/changes/ticket30454 b/changes/ticket30454
deleted file mode 100644
index 77c45d0fe..000000000
--- a/changes/ticket30454
+++ /dev/null
@@ -1,10 +0,0 @@
-  o Major bugfixes (hidden service v3):
-    - An intro point could try to send an INTRODUCE_ACK with a status code
-      that it wasn't able to encode leading to a hard assert() of the relay.
-      Fortunately, that specific code path can not be reached thus this issue
-      can't be triggered. We've consolidated the ABI values into trunnel now.
-      Fixes bug 30454; bugfix on 0.3.0.1-alpha.
-    - HSv3 client will now be able to properly handle unknown status code from
-      a INTRODUCE_ACK cell (nack) even if they do not know it. The NACK
-      behavior will stay the same. This will allow us to extend status code if
-      we want in the future without breaking the normal client behavior.
diff --git a/changes/ticket30591 b/changes/ticket30591
new file mode 100644
index 000000000..f97c02400
--- /dev/null
+++ b/changes/ticket30591
@@ -0,0 +1,3 @@
+  o Testing (continuous integration):
+    - In Travis, make stem log a controller trace to the console. And tail
+      stem's tor log after failure. Closes ticket 30591.
diff --git a/changes/ticket30686 b/changes/ticket30686
new file mode 100644
index 000000000..36473c1a0
--- /dev/null
+++ b/changes/ticket30686
@@ -0,0 +1,5 @@
+  o Minor features (logging):
+    - Give a more useful assertion failure message if we think we have
+      minherit() but we fail to make a region non-inheritable. Give a
+      compile-time warning if our support for minherit() is
+      incomplete. Closes ticket 30686.
diff --git a/changes/ticket30694 b/changes/ticket30694
new file mode 100644
index 000000000..70dbf6481
--- /dev/null
+++ b/changes/ticket30694
@@ -0,0 +1,3 @@
+  o Testing (continuous integration):
+    - In Travis, only run the stem tests that use a tor binary.
+      Closes ticket 30694.
diff --git a/changes/ticket30871 b/changes/ticket30871
new file mode 100644
index 000000000..81c076bb0
--- /dev/null
+++ b/changes/ticket30871
@@ -0,0 +1,6 @@
+  o Major bugfixes (circuit build, guard):
+    - When considering upgrading circuits from "waiting for guard" to "open",
+      always ignore the ones that are mark for close. Else, we can end up in
+      the situation where a subsystem is notified of that circuit opening but
+      still marked for close leading to undesirable behavior. Fixes bug 30871;
+      bugfix on 0.3.0.1-alpha.
diff --git a/changes/ticket31001 b/changes/ticket31001
new file mode 100644
index 000000000..2ce1cbdf3
--- /dev/null
+++ b/changes/ticket31001
@@ -0,0 +1,6 @@
+  o Minor bugfixes (compatibility, standards compliance):
+    - Fix a bug that would invoke undefined behavior on certain operating
+      systems when trying to asprintf() a string exactly INT_MAX bytes
+      long. We don't believe this is exploitable, but it's better
+      to fix it anyway. Fixes bug 31001; bugfix on 0.2.2.11-alpha.
+      Found and fixed by Tobias Stoeckmann.
diff --git a/changes/ticket31311 b/changes/ticket31311
new file mode 100644
index 000000000..88dfb8573
--- /dev/null
+++ b/changes/ticket31311
@@ -0,0 +1,3 @@
+  o Minor bugfixes (distribution):
+    - Do not ship any temporary files found in the scripts/maint/practracker
+      directory. Fixes bug 31311; bugfix on 0.4.1.1-alpha.
diff --git a/changes/ticket31374 b/changes/ticket31374
new file mode 100644
index 000000000..e8eef9cd4
--- /dev/null
+++ b/changes/ticket31374
@@ -0,0 +1,4 @@
+  o Minor bugfixes (compilation warning):
+    - Fix a compilation warning on Windows about casting a function
+      pointer for GetTickCount64(). Fixes bug 31374; bugfix on
+      0.2.9.1-alpha.
diff --git a/changes/ticket31406 b/changes/ticket31406
new file mode 100644
index 000000000..0ebe6f6c4
--- /dev/null
+++ b/changes/ticket31406
@@ -0,0 +1,3 @@
+  o Minor features (directory authority):
+    - A new IP address the directory authority "dizum" has been changed. Closes
+      ticket 31406;
diff --git a/configure.ac b/configure.ac
index 4b69b3c89..2295a9131 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4,7 +4,7 @@ dnl Copyright (c) 2007-2019, The Tor Project, Inc.
 dnl See LICENSE for licensing information
 
 AC_PREREQ([2.63])
-AC_INIT([tor],[0.4.0.5-dev])
+AC_INIT([tor],[0.4.1.5-dev])
 AC_CONFIG_SRCDIR([src/app/main/tor_main.c])
 AC_CONFIG_MACRO_DIR([m4])
 
@@ -14,7 +14,7 @@ AC_CONFIG_MACRO_DIR([m4])
 # version number changes.  Tor uses it to make sure that it
 # only shuts down for missing "required protocols" when those protocols
 # are listed as required by a consensus after this date.
-AC_DEFINE(APPROX_RELEASE_DATE, ["2019-05-02"], # for 0.4.0.5-dev
+AC_DEFINE(APPROX_RELEASE_DATE, ["2019-08-20"], # for 0.4.1.5-dev
           [Approximate date when this software was released. (Updated when the version changes.)])
 
 # "foreign" means we don't follow GNU package layout standards
@@ -949,21 +949,24 @@ AC_CHECK_MEMBERS([struct ssl_method_st.get_cipher_by_char], , ,
 [#include <openssl/ssl.h>
 ])
 
+dnl OpenSSL functions which we might not have.  In theory, we could just
+dnl check the openssl version number, but in practice that gets pretty
+dnl confusing with LibreSSL, OpenSSL, and various distributions' patches
+dnl to them.
 AC_CHECK_FUNCS([ \
 		ERR_load_KDF_strings \
+		EVP_PBE_scrypt \
+		EVP_sha3_256 \
+		SSL_CIPHER_find \
+		SSL_CTX_set1_groups_list \
+		SSL_CTX_set_security_level \
 		SSL_SESSION_get_master_key \
+		SSL_get_client_ciphers \
+		SSL_get_client_random \
 		SSL_get_server_random \
-                SSL_get_client_ciphers \
-                SSL_get_client_random \
-                SSL_CTX_set1_groups_list \
-		SSL_CIPHER_find \
-                SSL_CTX_set_security_level \
-		TLS_method
+		TLS_method \
 	       ])
 
-dnl Check if OpenSSL has scrypt implementation.
-AC_CHECK_FUNCS([ EVP_PBE_scrypt ])
-
 dnl Check if OpenSSL structures are opaque
 AC_CHECK_MEMBERS([SSL.state], , ,
 [#include <openssl/ssl.h>
@@ -975,6 +978,15 @@ AC_CHECK_SIZEOF(SHA_CTX, , [AC_INCLUDES_DEFAULT()
 
 fi # enable_nss
 
+dnl We will someday make KECCAK_TINY optional, but for now we still need
+dnl it for SHAKE, since OpenSSL's SHAKE can't be squeezed more than
+dnl once.  See comment in the definition of crypto_xof_t.
+
+dnl AM_CONDITIONAL(BUILD_KECCAK_TINY,
+dnl   test "x$ac_cv_func_EVP_sha3_256" != "xyes")
+
+AM_CONDITIONAL(BUILD_KECCAK_TINY, true)
+
 dnl ======================================================================
 dnl Can we use KIST?
 
@@ -1593,6 +1605,7 @@ AC_CHECK_MEMBERS([struct timeval.tv_sec], , ,
 AC_CHECK_SIZEOF(char)
 AC_CHECK_SIZEOF(short)
 AC_CHECK_SIZEOF(int)
+AC_CHECK_SIZEOF(unsigned int)
 AC_CHECK_SIZEOF(long)
 AC_CHECK_SIZEOF(long long)
 AC_CHECK_SIZEOF(__int64)
@@ -2444,9 +2457,7 @@ AC_CONFIG_FILES([
 	Doxyfile
 	Makefile
 	config.rust
-	contrib/dist/suse/tor.sh
 	contrib/operator-tools/tor.logrotate
-	contrib/dist/tor.sh
 	contrib/dist/torctl
 	contrib/dist/tor.service
 	src/config/torrc.sample
diff --git a/contrib/README b/contrib/README
index 3a94bb501..735fcf4c9 100644
--- a/contrib/README
+++ b/contrib/README
@@ -34,8 +34,6 @@ tools.  Everybody likes to write init scripts differently, it seems.
 
 tor.service is a sample service file for use with systemd.
 
-The suse/ subdirectory contains files used by the suse distribution.
-
 operator-tools/ -- Tools for Tor relay operators
 ------------------------------------------------
 
diff --git a/contrib/client-tools/torify b/contrib/client-tools/torify
index 54acfed65..ac4c9b5c7 100755
--- a/contrib/client-tools/torify
+++ b/contrib/client-tools/torify
@@ -53,7 +53,7 @@ pathfind() {
 
 if pathfind torsocks; then
     exec torsocks "$@"
-    echo "$0: Failed to exec torsocks $@" >&2
+    echo "$0: Failed to exec torsocks $*" >&2
     exit 1
 else
     echo "$0: torsocks not found in your PATH.  Perhaps it isn't installed?  (tsocks is no longer supported, for security reasons.)" >&2
diff --git a/contrib/dirauth-tools/nagios-check-tor-authority-cert b/contrib/dirauth-tools/nagios-check-tor-authority-cert
index 46dc7284b..75ff479a5 100755
--- a/contrib/dirauth-tools/nagios-check-tor-authority-cert
+++ b/contrib/dirauth-tools/nagios-check-tor-authority-cert
@@ -49,12 +49,12 @@ DIRSERVERS="$DIRSERVERS 80.190.246.100:80"      # gabelmoo
 DIRSERVERS="$DIRSERVERS 194.109.206.212:80"     # dizum
 DIRSERVERS="$DIRSERVERS 213.73.91.31:80"        # dannenberg
 
-TMPFILE="`tempfile`"
+TMPFILE=$(mktemp)
 trap 'rm -f "$TMPFILE"' 0
 
 for dirserver in $DIRSERVERS; do
-	wget -q -O "$TMPFILE" "http://$dirserver/tor/keys/fp/$identity"
-	if [ "$?" = 0 ]; then
+	if wget -q -O "$TMPFILE" "http://$dirserver/tor/keys/fp/$identity"
+        then
 		break
 	else
 		cat /dev/null > "$TMPFILE"
@@ -74,10 +74,10 @@ now=$(date +%s)
 if [ "$now" -ge "$expiryunix" ]; then
 	echo "CRITICAL: Certificate expired $expirydate (authority $identity)."
 	exit 2
-elif [ "$(( $now + 7*24*60*60 ))" -ge "$expiryunix" ]; then
+elif [ "$(( now + 7*24*60*60 ))" -ge "$expiryunix" ]; then
 	echo "CRITICAL: Certificate expires $expirydate (authority $identity)."
 	exit 2
-elif [ "$(( $now + 30*24*60*60 ))" -ge "$expiryunix" ]; then
+elif [ "$(( now + 30*24*60*60 ))" -ge "$expiryunix" ]; then
 	echo "WARNING: Certificate expires $expirydate (authority $identity)."
 	exit 1
 else
diff --git a/contrib/dist/suse/tor.sh.in b/contrib/dist/suse/tor.sh.in
deleted file mode 100644
index b7e9005eb..000000000
--- a/contrib/dist/suse/tor.sh.in
+++ /dev/null
@@ -1,118 +0,0 @@
-#!/bin/sh
-#
-# Copyright (c) 2006-2007 Andrew Lewman
-#
-# tor    The Onion Router
-#
-# Startup/shutdown script for tor. This is a wrapper around torctl;
-# torctl does the actual work in a relatively system-independent, or at least
-# distribution-independent, way, and this script deals with fitting the
-# whole thing into the conventions of the particular system at hand.
-#
-# These next couple of lines "declare" tor for the "chkconfig" program,
-# originally from SGI, used on Red Hat/Fedora and probably elsewhere.
-#
-# chkconfig: 2345 90 10
-# description: Onion Router - A low-latency anonymous proxy
-#
-
-### BEGIN INIT INFO
-# Provides: tor
-# Required-Start: $remote_fs $network
-# Required-Stop: $remote_fs $network
-# Default-Start: 3 5
-# Default-Stop: 0 1 2 6
-# Short-Description: Start the tor daemon
-# Description:  Start the tor daemon:  the anon-proxy server
-### END INIT INFO
-
-. /etc/rc.status
-
-# Shell functions sourced from /etc/rc.status:
-#      rc_check         check and set local and overall rc status
-#      rc_status        check and set local and overall rc status
-#      rc_status -v     ditto but be verbose in local rc status
-#      rc_status -v -r  ditto and clear the local rc status
-#      rc_failed        set local and overall rc status to failed
-#      rc_reset         clear local rc status (overall remains)
-#      rc_exit          exit appropriate to overall rc status
-
-# First reset status of this service
-rc_reset
-
-# Increase open file descriptors a reasonable amount
-ulimit -n 8192
-
-TORCTL=@BINDIR@/torctl
-
-# torctl will use these environment variables
-TORUSER=@TORUSER@
-export TORUSER
-TORGROUP=@TORGROUP@
-export TORGROUP
-
-TOR_DAEMON_PID_DIR="@LOCALSTATEDIR@/run/tor"
-
-if [ -x /bin/su ] ; then
-    SUPROG=/bin/su
-elif [ -x /sbin/su ] ; then
-    SUPROG=/sbin/su
-elif [ -x /usr/bin/su ] ; then
-    SUPROG=/usr/bin/su
-elif [ -x /usr/sbin/su ] ; then
-    SUPROG=/usr/sbin/su
-else
-    SUPROG=/bin/su
-fi
-
-case "$1" in
-
-    start)
-    echo "Starting tor daemon"
-
-    if [ ! -d $TOR_DAEMON_PID_DIR ] ; then
-        mkdir -p $TOR_DAEMON_PID_DIR
-        chown $TORUSER:$TORGROUP $TOR_DAEMON_PID_DIR
-    fi
-
-    ## Start daemon with startproc(8). If this fails
-    ## the echo return value is set appropriate.
-
-    startproc -f $TORCTL start
-    # Remember status and be verbose
-    rc_status -v
-    ;;
-
-    stop)
-    echo "Stopping tor daemon" 
-    startproc -f $TORCTL stop
-    # Remember status and be verbose
-    rc_status -v
-    ;;
-
-    restart)
-    echo "Restarting tor daemon" 
-    startproc -f $TORCTL restart
-    # Remember status and be verbose
-    rc_status -v
-    ;;
-
-    reload)
-    echo "Reloading tor daemon" 
-    startproc -f $TORCTL reload
-    # Remember status and be verbose
-    rc_status -v
-    ;;
-
-    status)
-    startproc -f $TORCTL status
-    # Remember status and be verbose
-    rc_status -v
-    ;;
-
-    *)
-    echo "Usage: $0 (start|stop|restart|reload|status)"
-    RETVAL=1
-esac
-
-rc_exit
diff --git a/contrib/dist/tor.sh.in b/contrib/dist/tor.sh.in
deleted file mode 100644
index 92f890681..000000000
--- a/contrib/dist/tor.sh.in
+++ /dev/null
@@ -1,123 +0,0 @@
-#!/bin/sh
-#
-# tor    The Onion Router
-#
-# Startup/shutdown script for tor. This is a wrapper around torctl;
-# torctl does the actual work in a relatively system-independent, or at least
-# distribution-independent, way, and this script deals with fitting the
-# whole thing into the conventions of the particular system at hand.
-# This particular script is written for Red Hat/Fedora Linux, and may
-# also work on Mandrake, but not SuSE.
-#
-# These next couple of lines "declare" tor for the "chkconfig" program,
-# originally from SGI, used on Red Hat/Fedora and probably elsewhere.
-#
-# chkconfig: 2345 90 10
-# description: Onion Router - A low-latency anonymous proxy
-#
-
-PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
-DAEMON=/usr/sbin/tor
-NAME=tor
-DESC="tor daemon"
-TORPIDDIR=/var/run/tor
-TORPID=$TORPIDDIR/tor.pid
-WAITFORDAEMON=60
-ARGS=""
-
-# Library functions
-if [ -f /etc/rc.d/init.d/functions ]; then
-   . /etc/rc.d/init.d/functions
-elif [ -f /etc/init.d/functions ]; then
-   . /etc/init.d/functions
-fi
-
-TORCTL=@BINDIR@/torctl
-
-# torctl will use these environment variables
-TORUSER=@TORUSER@
-export TORUSER
-
-if [ -x /bin/su ] ; then
-    SUPROG=/bin/su
-elif [ -x /sbin/su ] ; then
-    SUPROG=/sbin/su
-elif [ -x /usr/bin/su ] ; then
-    SUPROG=/usr/bin/su
-elif [ -x /usr/sbin/su ] ; then
-    SUPROG=/usr/sbin/su
-else
-    SUPROG=/bin/su
-fi
-
-# Raise ulimit based on number of file descriptors available (thanks, Debian)
-
-if [ -r /proc/sys/fs/file-max ]; then
-	system_max=`cat /proc/sys/fs/file-max`
-	if [ "$system_max" -gt "80000" ] ; then
-		MAX_FILEDESCRIPTORS=32768
-	elif [ "$system_max" -gt "40000" ] ; then
-		MAX_FILEDESCRIPTORS=16384
-	elif [ "$system_max" -gt "10000" ] ; then
-		MAX_FILEDESCRIPTORS=8192
-	else
-		MAX_FILEDESCRIPTORS=1024
-		cat << EOF
-
-Warning: Your system has very few filedescriptors available in total.
-
-Maybe you should try raising that by adding 'fs.file-max=100000' to your
-/etc/sysctl.conf file.  Feel free to pick any number that you deem appropriate.
-Then run 'sysctl -p'.  See /proc/sys/fs/file-max for the current value, and
-file-nr in the same directory for how many of those are used at the moment.
-
-EOF
-	fi
-else
-	MAX_FILEDESCRIPTORS=8192
-fi
-
-NICE=""
-
-case "$1" in
-
-    start)
-	if [ -n "$MAX_FILEDESCRIPTORS" ]; then
-		echo -n "Raising maximum number of filedescriptors (ulimit -n) to $MAX_FILEDESCRIPTORS"
-		if ulimit -n "$MAX_FILEDESCRIPTORS" ; then
-			echo "."
-		else
-			echo ": FAILED."
-		fi
-	fi
-
-    action $"Starting tor:" $TORCTL start
-    RETVAL=$?
-    ;;
-
-    stop)
-    action $"Stopping tor:" $TORCTL stop
-    RETVAL=$?
-    ;;
-
-    restart)
-    action $"Restarting tor:" $TORCTL restart
-    RETVAL=$?
-    ;;
-
-    reload)
-    action $"Reloading tor:" $TORCTL reload
-    RETVAL=$?
-    ;;
-
-    status)
-    $TORCTL status
-    RETVAL=$?
-    ;;
-
-    *)
-    echo "Usage: $0 (start|stop|restart|reload|status)"
-    RETVAL=1
-esac
-
-exit $RETVAL
diff --git a/contrib/include.am b/contrib/include.am
index a23e82d6d..8dd859330 100644
--- a/contrib/include.am
+++ b/contrib/include.am
@@ -3,11 +3,8 @@ EXTRA_DIST+= \
 	contrib/README					\
 	contrib/client-tools/torify			\
 	contrib/dist/rc.subr				\
-	contrib/dist/suse/tor.sh.in			\
-	contrib/dist/tor.sh				\
 	contrib/dist/torctl				\
 	contrib/dist/tor.service.in			\
-	contrib/operator-tools/linux-tor-prio.sh	\
 	contrib/operator-tools/tor-exit-notice.html	\
 	contrib/or-tools/exitlist			\
 	contrib/win32build/tor-mingw.nsi.in		\
diff --git a/contrib/operator-tools/linux-tor-prio.sh b/contrib/operator-tools/linux-tor-prio.sh
deleted file mode 100644
index 30ea5fc65..000000000
--- a/contrib/operator-tools/linux-tor-prio.sh
+++ /dev/null
@@ -1,192 +0,0 @@
-#!/bin/bash
-# Written by Marco Bonetti & Mike Perry
-# Based on instructions from Dan Singletary's ADSL BW Management HOWTO:
-# http://www.faqs.org/docs/Linux-HOWTO/ADSL-Bandwidth-Management-HOWTO.html
-# This script is Public Domain.
-
-############################### README #################################
-
-# This script provides prioritization of Tor traffic below other
-# traffic on a Linux server. It has two modes of operation: UID based 
-# and IP based. 
-
-# UID BASED PRIORITIZATION
-#
-# The UID based method requires that Tor be launched from 
-# a specific user ID. The "User" Tor config setting is
-# insufficient, as it sets the UID after the socket is created.
-# Here is a C wrapper you can use to execute Tor and drop privs before 
-# it creates any sockets. 
-#
-# Compile with:
-# gcc -DUID=`id -u tor` -DGID=`id -g tor` tor_wrap.c -o tor_wrap
-#
-# #include <unistd.h>
-# int main(int argc, char **argv) {
-# if(initgroups("tor", GID) == -1) { perror("initgroups"); return 1; }
-# if(setresgid(GID, GID, GID) == -1) { perror("setresgid"); return 1; }
-# if(setresuid(UID, UID, UID) == -1) { perror("setresuid"); return 1; }
-# execl("/bin/tor", "/bin/tor", "-f", "/etc/tor/torrc", NULL);
-# perror("execl"); return 1;
-# }
-
-# IP BASED PRIORITIZATION
-#
-# The IP setting requires that a separate IP address be dedicated to Tor. 
-# Your Torrc should be set to bind to this IP for "OutboundBindAddress", 
-# "ListenAddress", and "Address".
-
-# GENERAL USAGE
-#
-# You should also tune the individual connection rate parameters below
-# to your individual connection. In particular, you should leave *some* 
-# minimum amount of bandwidth for Tor, so that Tor users are not 
-# completely choked out when you use your server's bandwidth. 30% is 
-# probably a reasonable choice. More is better of course.
-#
-# To start the shaping, run it as: 
-#   ./linux-tor-prio.sh 
-#
-# To get status information (useful to verify packets are getting marked
-# and prioritized), run:
-#   ./linux-tor-prio.sh status
-#
-# And to stop prioritization:
-#   ./linux-tor-prio.sh stop
-#
-########################################################################
-
-# BEGIN USER TUNABLE PARAMETERS
-
-DEV=eth0
-
-# NOTE! You must START Tor under this UID. Using the Tor User
-# config setting is NOT sufficient. See above.
-TOR_UID=$(id -u tor)
-
-# If the UID mechanism doesn't work for you, you can set this parameter
-# instead. If set, it will take precedence over the UID setting. Note that
-# you need multiple IPs with one specifically devoted to Tor for this to
-# work.
-#TOR_IP="42.42.42.42"
-
-# Average ping to most places on the net, milliseconds
-RTT_LATENCY=40
-
-# RATE_UP must be less than your connection's upload capacity in
-# kbits/sec. If it is larger, then the bottleneck will be at your
-# router's queue, which you do not control. This will cause congestion
-# and a revert to normal TCP fairness no matter what the queing
-# priority is.
-RATE_UP=5000
-
-# RATE_UP_TOR is the minimum speed your Tor connections will have in
-# kbits/sec.  They will have at least this much bandwidth for upload.
-# In general, you probably shouldn't set this too low, or else Tor
-# users who use your node will be completely choked out whenever your
-# machine does any other network activity. That is not very fun.
-RATE_UP_TOR=1500
-
-# RATE_UP_TOR_CEIL is the maximum rate allowed for all Tor traffic in
-# kbits/sec.
-RATE_UP_TOR_CEIL=5000
-
-CHAIN=OUTPUT
-#CHAIN=PREROUTING
-#CHAIN=POSTROUTING
-
-MTU=1500
-AVG_PKT=900 # should be more like 600 for non-exit nodes
-
-# END USER TUNABLE PARAMETERS
-
-
-
-# The queue size should be no larger than your bandwidth-delay
-# product. This is RT latency*bandwidth/MTU/2
-
-BDP=$(expr $RTT_LATENCY \* $RATE_UP / $AVG_PKT)
-
-# Further research indicates that the BDP calculations should use
-# RTT/sqrt(n) where n is the expected number of active connections..
-
-BDP=$(expr $BDP / 4)
-
-if [ "$1" = "status" ]
-then
-	echo "[qdisc]"
-	tc -s qdisc show dev $DEV
-	tc -s qdisc show dev imq0
-	echo "[class]"
-	tc -s class show dev $DEV
-	tc -s class show dev imq0
-	echo "[filter]"
-	tc -s filter show dev $DEV
-	tc -s filter show dev imq0
-	echo "[iptables]"
-	iptables -t mangle -L TORSHAPER-OUT -v -x 2> /dev/null
-	exit
-fi
-
-
-# Reset everything to a known state (cleared)
-tc qdisc del dev $DEV root 2> /dev/null > /dev/null
-tc qdisc del dev imq0 root 2> /dev/null > /dev/null
-iptables -t mangle -D POSTROUTING -o $DEV -j TORSHAPER-OUT 2> /dev/null > /dev/null
-iptables -t mangle -D PREROUTING -o $DEV -j TORSHAPER-OUT 2> /dev/null > /dev/null
-iptables -t mangle -D OUTPUT -o $DEV -j TORSHAPER-OUT 2> /dev/null > /dev/null
-iptables -t mangle -F TORSHAPER-OUT 2> /dev/null > /dev/null
-iptables -t mangle -X TORSHAPER-OUT 2> /dev/null > /dev/null
-ip link set imq0 down 2> /dev/null > /dev/null
-rmmod imq 2> /dev/null > /dev/null
-
-if [ "$1" = "stop" ]
-then
-	echo "Shaping removed on $DEV."
-	exit
-fi
-
-# Outbound Shaping (limits total bandwidth to RATE_UP)
-
-ip link set dev $DEV qlen $BDP
-
-# Add HTB root qdisc, default is high prio
-tc qdisc add dev $DEV root handle 1: htb default 20
-
-# Add main rate limit class
-tc class add dev $DEV parent 1: classid 1:1 htb rate ${RATE_UP}kbit
-
-# Create the two classes, giving Tor at least RATE_UP_TOR kbit and capping
-# total upstream at RATE_UP so the queue is under our control.
-tc class add dev $DEV parent 1:1 classid 1:20 htb rate $(expr $RATE_UP - $RATE_UP_TOR)kbit ceil ${RATE_UP}kbit prio 0
-tc class add dev $DEV parent 1:1 classid 1:21 htb rate $[$RATE_UP_TOR]kbit ceil ${RATE_UP_TOR_CEIL}kbit prio 10
-
-# Start up pfifo
-tc qdisc add dev $DEV parent 1:20 handle 20: pfifo limit $BDP
-tc qdisc add dev $DEV parent 1:21 handle 21: pfifo limit $BDP
-
-# filter traffic into classes by fwmark
-tc filter add dev $DEV parent 1:0 prio 0 protocol ip handle 20 fw flowid 1:20
-tc filter add dev $DEV parent 1:0 prio 0 protocol ip handle 21 fw flowid 1:21
-
-# add TORSHAPER-OUT chain to the mangle table in iptables
-iptables -t mangle -N TORSHAPER-OUT
-iptables -t mangle -I $CHAIN -o $DEV -j TORSHAPER-OUT
-
-
-# Set firewall marks
-# Low priority to Tor
-if [ ""$TOR_IP == "" ]
-then
-	echo "Using UID-based QoS. UID $TOR_UID marked as low priority."
-	iptables -t mangle -A TORSHAPER-OUT -m owner --uid-owner $TOR_UID -j MARK --set-mark 21
-else
-	echo "Using IP-based QoS. $TOR_IP marked as low priority."
-	iptables -t mangle -A TORSHAPER-OUT -s $TOR_IP -j MARK --set-mark 21
-fi
-
-# High prio for everything else
-iptables -t mangle -A TORSHAPER-OUT -m mark --mark 0 -j MARK --set-mark 20
-
-echo "Outbound shaping added to $DEV.  Rate for Tor upload at least: ${RATE_UP_TOR}Kbyte/sec."
-
diff --git a/contrib/win32build/tor-mingw.nsi.in b/contrib/win32build/tor-mingw.nsi.in
index 7b3cf2116..25c911d93 100644
--- a/contrib/win32build/tor-mingw.nsi.in
+++ b/contrib/win32build/tor-mingw.nsi.in
@@ -8,7 +8,7 @@
 !include "LogicLib.nsh"
 !include "FileFunc.nsh"
 !insertmacro GetParameters
-!define VERSION "0.4.0.5-dev"
+!define VERSION "0.4.1.5-dev"
 !define INSTALLER "tor-${VERSION}-win32.exe"
 !define WEBSITE "https://www.torproject.org/"
 !define LICENSE "LICENSE"
diff --git a/doc/HACKING/CodingStandards.md b/doc/HACKING/CodingStandards.md
index 4f229348e..74db2a39a 100644
--- a/doc/HACKING/CodingStandards.md
+++ b/doc/HACKING/CodingStandards.md
@@ -110,12 +110,41 @@ it's a bugfix, mention what bug it fixes and when the bug was
 introduced.  To find out which Git tag the change was introduced in,
 you can use `git describe --contains <sha1 of commit>`.
 
-If at all possible, try to create this file in the same commit where you are
-making the change.  Please give it a distinctive name that no other branch will
-use for the lifetime of your change. To verify the format of the changes file,
-you can use `make check-changes`.  This is run automatically as part of
-`make check` -- if it fails, we must fix it before we release.  These
-checks are implemented in `scripts/maint/lintChanges.py`.
+If you don't know the commit, you can search the git diffs (-S) for the first
+instance of the feature (--reverse).
+
+For example, for #30224, we wanted to know when the bridge-distribution-request
+feature was introduced into Tor:
+    $ git log -S bridge-distribution-request --reverse
+    commit ebab521525
+    Author: Roger Dingledine <arma@torproject.org>
+    Date:   Sun Nov 13 02:39:16 2016 -0500
+
+        Add new BridgeDistribution config option
+
+    $ git describe --contains ebab521525
+    tor-0.3.2.3-alpha~15^2~4
+
+If you need to know all the Tor versions that contain a commit, use:
+    $ git tag --contains 9f2efd02a1 | sort -V
+    tor-0.2.5.16
+    tor-0.2.8.17
+    tor-0.2.9.14
+    tor-0.2.9.15
+    ...
+    tor-0.3.0.13
+    tor-0.3.1.9
+    tor-0.3.1.10
+    ...
+
+If at all possible, try to create the changes file in the same commit where
+you are making the change.  Please give it a distinctive name that no other
+branch will use for the lifetime of your change. We usually use "ticketNNNNN"
+or "bugNNNNN", where NNNNN is the ticket number. To verify the format of the
+changes file, you can use `make check-changes`.  This is run automatically as
+part of `make check` -- if it fails, we must fix it as soon as possible, so
+that our CI passes.  These checks are implemented in
+`scripts/maint/lintChanges.py`.
 
 Changes file style guide:
   * Changes files begin with "  o Header (subheading):".  The header
diff --git a/doc/HACKING/CodingStandardsRust.md b/doc/HACKING/CodingStandardsRust.md
index fc562816d..b570e10dc 100644
--- a/doc/HACKING/CodingStandardsRust.md
+++ b/doc/HACKING/CodingStandardsRust.md
@@ -256,7 +256,7 @@ Here are some additional bits of advice and rules:
    or 2) should fail (i.e. in a unittest).
 
    You SHOULD NOT use `unwrap()` anywhere in which it is possible to handle the
-   potential error with either `expect()` or the eel operator, `?`.
+   potential error with the eel operator, `?` or another non panicking way.
    For example, consider a function which parses a string into an integer:
 
         fn parse_port_number(config_string: &str) -> u16 {
@@ -264,12 +264,12 @@ Here are some additional bits of advice and rules:
         }
 
    There are numerous ways this can fail, and the `unwrap()` will cause the
-   whole program to byte the dust!  Instead, either you SHOULD use `expect()`
+   whole program to byte the dust!  Instead, either you SHOULD use `ok()`
    (or another equivalent function which will return an `Option` or a `Result`)
    and change the return type to be compatible:
 
         fn parse_port_number(config_string: &str) -> Option<u16> {
-            u16::from_str_radix(config_string, 10).expect("Couldn't parse port into a u16")
+            u16::from_str_radix(config_string, 10).ok()
         }
 
    or you SHOULD use `or()` (or another similar method):
diff --git a/doc/HACKING/HelpfulTools.md b/doc/HACKING/HelpfulTools.md
index d49923852..cba57e875 100644
--- a/doc/HACKING/HelpfulTools.md
+++ b/doc/HACKING/HelpfulTools.md
@@ -371,3 +371,18 @@ source code. Here's how to use it:
 
   6. See the Doxygen manual for more information; this summary just
      scratches the surface.
+
+Style and best-pratices checking
+--------------------------------
+
+We use scripts to check for various problems in the formatting and style
+of our source code.  The "check-spaces" test detects a bunch of violations
+of our coding style on the local level.  The "check-best-practices" test
+looks for violations of some of our complexity guidelines.
+
+You can tell the tool about exceptions to the complexity guidelines via its
+exceptions file (scripts/maint/practracker/exceptions.txt).  But before you
+do this, consider whether you shouldn't fix the underlying problem.  Maybe
+that file really _is_ too big.  Maybe that function really _is_ doing too
+much.  (On the other hand, for stable release series, it is sometimes better
+to leave things unrefactored.)
diff --git a/doc/HACKING/ReleasingTor.md b/doc/HACKING/ReleasingTor.md
index 7334b1b34..a97ca08ce 100644
--- a/doc/HACKING/ReleasingTor.md
+++ b/doc/HACKING/ReleasingTor.md
@@ -20,8 +20,11 @@ new Tor release:
 
 === I. Make sure it works
 
-1. Make sure that CI passes: have a look at Travis, Appveyor, and
-   Jenkins.  Make sure you're looking at the right branches.
+1. Make sure that CI passes: have a look at Travis
+   (https://travis-ci.org/torproject/tor/branches), Appveyor
+   (https://ci.appveyor.com/project/torproject/tor/history), and
+   Jenkins (https://jenkins.torproject.org/view/tor/).
+   Make sure you're looking at the right branches.
 
    If there are any unexplained failures, try to fix them or figure them
    out.
@@ -40,10 +43,14 @@ new Tor release:
     * clang scan-build.  (See the script in ./scripts/test/scan_build.sh)
 
     * make test-network and make test-network-all (with
-      --enable-expensive-hardening)
+      --enable-fragile-hardening)
 
     * Running Tor yourself and making sure that it actually works for you.
 
+    * Running Tor under valgrind.  (Our 'fragile hardening' doesn't cover
+      libevent and openssl, so using valgrind will sometimes find extra
+      memory leaks.)
+
 
 === II. Write a changelog
 
@@ -176,7 +183,8 @@ new Tor release:
    `/srv/dist-master.torproject.org/htdocs/` on dist-master. Run
    "static-update-component dist.torproject.org" on dist-master.
 
-   In the webwml.git repository, `include/versions.wmi` and `Makefile`
+   In the webwml.git repository, `include/versions.wmi` and `Makefile`.
+   In the project/web/tpo.git repository, update `databags/versions.ini`
    to note the new version.  Push these changes to master.
 
    (NOTE: Due to #17805, there can only be one stable version listed at
@@ -243,3 +251,5 @@ new Tor release:
    master branch.
 
 3. Keep an eye on the blog post, to moderate comments and answer questions.
+
+
diff --git a/doc/asciidoc-helper.sh b/doc/asciidoc-helper.sh
index a3ef53f88..765850a12 100755
--- a/doc/asciidoc-helper.sh
+++ b/doc/asciidoc-helper.sh
@@ -19,7 +19,7 @@ if [ "$1" = "html" ]; then
     base=${output%%.html.in}
 
     if [ "$2" != none ]; then
-      TZ=UTC "$2" -d manpage -o $output $input;
+      TZ=UTC "$2" -d manpage -o "$output" "$input";
     else
       echo "==================================";
       echo;
@@ -44,8 +44,8 @@ elif [ "$1" = "man" ]; then
       echo "==================================";
       exit 1;
     fi
-    if "$2" -f manpage $input; then
-      mv $base.1 $output;
+    if "$2" -f manpage "$input"; then
+      mv "$base.1" "$output";
     else
       cat<<EOF
 ==================================
diff --git a/doc/tor.1.txt b/doc/tor.1.txt
index a02b1372c..95d56c6db 100644
--- a/doc/tor.1.txt
+++ b/doc/tor.1.txt
@@ -151,8 +151,8 @@ instance, you can tell Tor to start listening for SOCKS connections on port
 9999 by passing --SocksPort 9999 or SocksPort 9999 to it on the command line,
 or by putting "SocksPort 9999" in the configuration file.  You will need to
 quote options with spaces in them: if you want Tor to log all debugging
-messages to debug.log, you will probably need to say --Log 'debug file
-debug.log'.
+messages to debug.log, you will probably need to say **--Log** `"debug file
+debug.log"`.
 
 Options on the command line override those in configuration files. See the
 next section for more information.
@@ -683,7 +683,7 @@ GENERAL OPTIONS
     The currently recognized domains are: general, crypto, net, config, fs,
     protocol, mm, http, app, control, circ, rend, bug, dir, dirserv, or, edge,
     acct, hist, handshake, heartbeat, channel, sched, guard, consdiff, dos,
-    process, pt, and btrack.
+    process, pt, btrack, and mesg.
     Domain names are case-insensitive. +
  +
     For example, "`Log [handshake]debug [~net,~mm]info notice stdout`" sends
@@ -959,6 +959,20 @@ The following options are useful only for clients (that is, if
     this option. This option should be offered via the UI to mobile users
     for use where bandwidth may be expensive. (Default: 0)
 
+[[CircuitPadding]] **CircuitPadding** **0**|**1**::
+    If set to 0, Tor will not pad client circuits with additional cover
+    traffic. Only clients may set this option. This option should be offered
+    via the UI to mobile users for use where bandwidth may be expensive. If
+    set to 1, padding will be negotiated as per the consensus and relay
+    support (unlike ConnectionPadding, CircuitPadding cannot be force-enabled).
+    (Default: 1)
+
+[[ReducedCircuitPadding]] **ReducedCircuitPadding** **0**|**1**::
+    If set to 1, Tor will only use circuit padding algorithms that have low
+    overhead. Only clients may set this option. This option should be offered
+    via the UI to mobile users for use where bandwidth may be expensive.
+    (Default: 0)
+
 [[ExcludeNodes]] **ExcludeNodes** __node__,__node__,__...__::
     A list of identity fingerprints, country codes, and address
     patterns of nodes to avoid when building a circuit. Country codes are
@@ -1060,8 +1074,8 @@ The following options are useful only for clients (that is, if
 [[StrictNodes]] **StrictNodes** **0**|**1**::
     If StrictNodes is set to 1, Tor will treat solely the ExcludeNodes option
     as a requirement to follow for all the circuits you generate, even if
-    doing so will break functionality for you (StrictNodes applies to neither
-    ExcludeExitNodes nor to ExitNodes, nor to MiddleNodes).  If StrictNodes
+    doing so will break functionality for you (StrictNodes does not apply to
+    ExcludeExitNodes, ExitNodes, MiddleNodes, or MapAddress).  If StrictNodes
     is set to 0, Tor will still try to avoid nodes in the ExcludeNodes list,
     but it will err on the side of avoiding unexpected errors.
     Specifically, StrictNodes 0 tells Tor that it is okay to use an excluded
@@ -1157,7 +1171,9 @@ The following options are useful only for clients (that is, if
     "MapAddress \*.example.com \*.example.com.torserver.exit". (Note the
     leading "*." in each part of the directive.) You can also redirect all
     subdomains of a domain to a single address. For example, "MapAddress
-    *.example.com www.example.com". +
+    *.example.com www.example.com". If the specified exit is not available,
+    or the exit can not connect to the site, Tor will fail any connections
+    to the mapped address.+
  +
     NOTES:
 
@@ -1185,6 +1201,15 @@ The following options are useful only for clients (that is, if
     4. Using a wildcard to match only part of a string (as in *ample.com) is
     also invalid.
 
+    5. Tor maps hostnames and IP addresses separately. If you MapAddress
+       a DNS name, but use an IP address to connect, then Tor will ignore the
+       DNS name mapping.
+
+    6. MapAddress does not apply to redirects in the application protocol.
+       For example, HTTP redirects and alt-svc headers will ignore mappings
+       for the original address. You can use a wildcard mapping to handle
+       redirects within the same site.
+
 [[NewCircuitPeriod]] **NewCircuitPeriod** __NUM__::
     Every NUM seconds consider whether to build a new circuit. (Default: 30
     seconds)
@@ -1939,13 +1964,14 @@ is non-zero):
     exit according to the ExitPolicy option, the ReducedExitPolicy option,
     or the default ExitPolicy (if no other exit policy option is specified). +
  +
-    If ExitRelay is set to 0, no traffic is allowed to
-    exit, and the ExitPolicy and ReducedExitPolicy options are ignored. +
+    If ExitRelay is set to 0, no traffic is allowed to exit, and the
+    ExitPolicy, ReducedExitPolicy, and IPv6Exit options are ignored. +
  +
-    If ExitRelay is set to "auto", then Tor checks the ExitPolicy and
-    ReducedExitPolicy options. If either is set, Tor behaves as if ExitRelay
-    were set to 1. If neither exit policy option is set, Tor behaves as if
-    ExitRelay were set to 0. (Default: auto)
+    If ExitRelay is set to "auto", then Tor checks the ExitPolicy,
+    ReducedExitPolicy, and IPv6Exit options. If at least one of these options
+    is set, Tor behaves as if ExitRelay were set to 1. If none of these exit
+    policy options are set, Tor behaves as if ExitRelay were set to 0.
+    (Default: auto)
 
 [[ExitPolicy]] **ExitPolicy** __policy__,__policy__,__...__::
     Set an exit policy for this server. Each policy is of the form
@@ -2140,8 +2166,9 @@ is non-zero):
     (Default: 0)
 
 [[IPv6Exit]] **IPv6Exit** **0**|**1**::
-    If set, and we are an exit node, allow clients to use us for IPv6
-    traffic. (Default: 0)
+    If set, and we are an exit node, allow clients to use us for IPv6 traffic.
+    When this option is set and ExitRelay is auto, we act as if ExitRelay
+    is 1. (Default: 0)
 
 [[MaxOnionQueueDelay]] **MaxOnionQueueDelay** __NUM__ [**msec**|**second**]::
     If we have more onionskins queued for processing than we can process in
@@ -2341,7 +2368,8 @@ is non-zero):
     When this option is enabled and BridgeRelay is also enabled, and we have
     GeoIP data, Tor keeps a per-country count of how many client
     addresses have contacted it so that it can help the bridge authority guess
-    which countries have blocked access to it. (Default: 1)
+    which countries have blocked access to it. If ExtraInfoStatistics is
+    enabled, it will be published as part of extra-info document. (Default: 1)
 
 [[ServerDNSRandomizeCase]] **ServerDNSRandomizeCase** **0**|**1**::
     When this option is set, Tor sets the case of each character randomly in
@@ -2423,6 +2451,10 @@ is non-zero):
 [[ExtraInfoStatistics]] **ExtraInfoStatistics** **0**|**1**::
     When this option is enabled, Tor includes previously gathered statistics in
     its extra-info documents that it uploads to the directory authorities.
+    Disabling this option also removes bandwidth usage statistics, and
+    GeoIPFile and GeoIPv6File hashes from the extra-info file. Bridge
+    ServerTransportPlugin lines are always includes in the extra-info file,
+    because they are required by BridgeDB.
     (Default: 1)
 
 [[ExtendAllowPrivateAddresses]] **ExtendAllowPrivateAddresses** **0**|**1**::
diff --git a/scripts/coccinelle/ctrl-reply-cleanup.cocci b/scripts/coccinelle/ctrl-reply-cleanup.cocci
new file mode 100644
index 000000000..f085cd468
--- /dev/null
+++ b/scripts/coccinelle/ctrl-reply-cleanup.cocci
@@ -0,0 +1,43 @@
+// Script to clean up after ctrl-reply.cocci -- run as a separate step
+// because cleanup_write2 (even when disabled) somehow prevents the
+// match rule in ctrl-reply.cocci from matching.
+
+// If it doesn't have to be a printf, turn it into a write
+
+@ cleanup_write @
+expression E;
+constant code, s;
+@@
+-control_printf_endreply(E, code, s)
++control_write_endreply(E, code, s)
+
+// Use send_control_done() instead of explicitly writing it out
+@ cleanup_send_done @
+type T;
+identifier f != send_control_done;
+expression E;
+@@
+ T f(...) {
+<...
+-control_write_endreply(E, 250, "OK")
++send_control_done(E)
+ ...>
+ }
+
+// Clean up more printfs that could be writes
+//
+// For some reason, including this rule, even disabled, causes the
+// match rule in ctrl-reply.cocci to fail to match some code that has
+// %s in its format strings
+
+@ cleanup_write2 @
+expression E1, E2;
+constant code;
+@@
+(
+-control_printf_endreply(E1, code, "%s", E2)
++control_write_endreply(E1, code, E2)
+|
+-control_printf_midreply(E1, code, "%s", E2)
++control_write_midreply(E1, code, E2)
+)
diff --git a/scripts/coccinelle/ctrl-reply.cocci b/scripts/coccinelle/ctrl-reply.cocci
new file mode 100644
index 000000000..d6e9aeedd
--- /dev/null
+++ b/scripts/coccinelle/ctrl-reply.cocci
@@ -0,0 +1,87 @@
+// Script to edit control_*.c for refactored control reply output functions
+
+@ initialize:python @
+@@
+import re
+from coccilib.report import *
+
+# reply strings "NNN-foo", "NNN+foo", "NNN foo", etc.
+r = re.compile(r'^"(\d+)([ +-])(.*)\\r\\n"$')
+
+# Generate name of function to call based on which separator character
+# comes between the numeric code and the text
+def idname(sep, base):
+    if sep == '+':
+        return base + "datareply"
+    elif sep == '-':
+        return base + "midreply"
+    else:
+        return base + "endreply"
+
+# Generate the actual replacements used by the rules
+def gen(s, base, p):
+    pos = p[0]
+    print_report(pos, "%s %s" % (base, s))
+    m = r.match(s)
+    if m is None:
+        # String not correct format, so fail match
+        cocci.include_match(False)
+        print_report(pos, "BAD STRING %s" % s)
+        return
+
+    code, sep, s1 = m.groups()
+
+    if r'\r\n' in s1:
+        # Extra CRLF in string, so fail match
+        cocci.include_match(False)
+        print_report(pos, "extra CRLF in string %s" % s)
+        return
+
+    coccinelle.code = code
+    # Need a string that is a single C token, because Coccinelle only allows
+    # "identifiers" to be output from Python scripts?
+    coccinelle.body = '"%s"' % s1
+    coccinelle.id = idname(sep, base)
+    return
+
+@ match @
+identifier f;
+position p;
+expression E;
+constant s;
+@@
+(
+ connection_printf_to_buf@f@p(E, s, ...)
+|
+ connection_write_str_to_buf@f@p(s, E)
+)
+
+@ script:python sc1 @
+s << match.s;
+p << match.p;
+f << match.f;
+id;
+body;
+code;
+@@
+if f == 'connection_printf_to_buf':
+    gen(s, 'control_printf_', p)
+elif f == 'connection_write_str_to_buf':
+    gen(s, 'control_write_', p)
+else:
+    raise(ValueError("%s: %s" % (f, s)))
+
+@ replace @
+constant match.s;
+expression match.E;
+identifier match.f;
+identifier sc1.body, sc1.id, sc1.code;
+@@
+(
+-connection_write_str_to_buf@f(s, E)
++id(E, code, body)
+|
+-connection_printf_to_buf@f(E, s
++id(E, code, body
+ , ...)
+)
diff --git a/scripts/coccinelle/tor-coccinelle.h b/scripts/coccinelle/tor-coccinelle.h
new file mode 100644
index 000000000..8f625dcee
--- /dev/null
+++ b/scripts/coccinelle/tor-coccinelle.h
@@ -0,0 +1,3 @@
+#define MOCK_IMPL(a, b, c) a b c
+#define CHECK_PRINTF(a, b)
+#define STATIC static
diff --git a/scripts/git/git-merge-forward.sh b/scripts/git/git-merge-forward.sh
new file mode 100755
index 000000000..67af7e98b
--- /dev/null
+++ b/scripts/git/git-merge-forward.sh
@@ -0,0 +1,236 @@
+#!/bin/bash
+
+##############################
+# Configuration (change me!) #
+##############################
+
+# The general setup that is suggested here is:
+#
+#   GIT_PATH = /home/<user>/git/
+#     ... where the git repository directories resides.
+#   TOR_MASTER_NAME = "tor"
+#     ... which means that tor.git was cloned in /home/<user>/git/tor
+#   TOR_WKT_NAME = "tor-wkt"
+#     ... which means that the tor worktrees are in /home/<user>/git/tor-wkt
+
+# Where are all those git repositories?
+GIT_PATH="FULL_PATH_TO_GIT_REPOSITORY_DIRECTORY"
+# The tor master git repository directory from which all the worktree have
+# been created.
+TOR_MASTER_NAME="tor"
+# The worktrees location (directory).
+TOR_WKT_NAME="tor-wkt"
+
+#########################
+# End of configuration. #
+#########################
+
+# Configuration of the branches that needs merging. The values are in order:
+#   (1) Branch name that we merge onto.
+#   (2) Branch name to merge from. In other words, this is merge into (1)
+#   (3) Full path of the git worktree.
+#
+# As an example:
+#   $ cd <PATH/TO/WORKTREE> (3)
+#   $ git checkout maint-0.3.5 (1)
+#   $ git pull
+#   $ git merge maint-0.3.4 (2)
+#
+# First set of arrays are the maint-* branch and then the release-* branch.
+# New arrays need to be in the WORKTREE= array else they aren't considered.
+MAINT_034=( "maint-0.3.4" "maint-0.2.9" "$GIT_PATH/$TOR_WKT_NAME/maint-0.3.4" )
+MAINT_035=( "maint-0.3.5" "maint-0.3.4" "$GIT_PATH/$TOR_WKT_NAME/maint-0.3.5" )
+MAINT_040=( "maint-0.4.0" "maint-0.3.5" "$GIT_PATH/$TOR_WKT_NAME/maint-0.4.0" )
+MAINT_MASTER=( "master" "maint-0.4.0" "$GIT_PATH/$TOR_MASTER_NAME" )
+
+RELEASE_029=( "release-0.2.9" "maint-0.2.9" "$GIT_PATH/$TOR_WKT_NAME/release-0.2.9" )
+RELEASE_034=( "release-0.3.4" "maint-0.3.4" "$GIT_PATH/$TOR_WKT_NAME/release-0.3.4" )
+RELEASE_035=( "release-0.3.5" "maint-0.3.5" "$GIT_PATH/$TOR_WKT_NAME/release-0.3.5" )
+RELEASE_040=( "release-0.4.0" "maint-0.4.0" "$GIT_PATH/$TOR_WKT_NAME/release-0.4.0" )
+
+# The master branch path has to be the main repository thus contains the
+# origin that will be used to fetch the updates. All the worktrees are created
+# from that repository.
+ORIGIN_PATH="$GIT_PATH/$TOR_MASTER_NAME"
+
+# SC2034 -- shellcheck thinks that these are unused.  We know better.
+ACTUALLY_THESE_ARE_USED=<<EOF
+${MAINT_034[0]}
+${MAINT_035[0]}
+${MAINT_040[0]}
+${MAINT_MASTER[0]}
+${RELEASE_029[0]}
+${RELEASE_034[0]}
+${RELEASE_035[0]}
+${RELEASE_040[0]}
+EOF
+
+##########################
+# Git Worktree to manage #
+##########################
+
+# List of all worktrees to work on. All defined above. Ordering is important.
+# Always the maint-* branch BEFORE then the release-*.
+WORKTREE=(
+  RELEASE_029[@]
+
+  MAINT_034[@]
+  RELEASE_034[@]
+
+  MAINT_035[@]
+  RELEASE_035[@]
+
+  MAINT_040[@]
+  RELEASE_040[@]
+
+  MAINT_MASTER[@]
+)
+COUNT=${#WORKTREE[@]}
+
+# Controlled by the -n option. The dry run option will just output the command
+# that would have been executed for each worktree.
+DRY_RUN=0
+
+# Control characters
+CNRM=$'\x1b[0;0m'   # Clear color
+
+# Bright color
+BGRN=$'\x1b[1;32m'
+BBLU=$'\x1b[1;34m'
+BRED=$'\x1b[1;31m'
+BYEL=$'\x1b[1;33m'
+IWTH=$'\x1b[3;37m'
+
+# Strings for the pretty print.
+MARKER="${BBLU}[${BGRN}+${BBLU}]${CNRM}"
+SUCCESS="${BGRN}success${CNRM}"
+FAILED="${BRED}failed${CNRM}"
+
+####################
+# Helper functions #
+####################
+
+# Validate the given returned value (error code), print success or failed. The
+# second argument is the error output in case of failure, it is printed out.
+# On failure, this function exits.
+function validate_ret
+{
+  if [ "$1" -eq 0 ]; then
+    printf "%s\\n" "$SUCCESS"
+  else
+    printf "%s\\n" "$FAILED"
+    printf "    %s" "$2"
+    exit 1
+  fi
+}
+
+# Switch to the given branch name.
+function switch_branch
+{
+  local cmd="git checkout $1"
+  printf "  %s Switching branch to %s..." "$MARKER" "$1"
+  if [ $DRY_RUN -eq 0 ]; then
+    msg=$( eval "$cmd" 2>&1 )
+    validate_ret $? "$msg"
+  else
+    printf "\\n      %s\\n" "${IWTH}$cmd${CNRM}"
+  fi
+}
+
+# Pull the given branch name.
+function pull_branch
+{
+  local cmd="git pull"
+  printf "  %s Pulling branch %s..." "$MARKER" "$1"
+  if [ $DRY_RUN -eq 0 ]; then
+    msg=$( eval "$cmd" 2>&1 )
+    validate_ret $? "$msg"
+  else
+    printf "\\n      %s\\n" "${IWTH}$cmd${CNRM}"
+  fi
+}
+
+# Merge the given branch name ($2) into the current branch ($1).
+function merge_branch
+{
+  local cmd="git merge --no-edit $1"
+  printf "  %s Merging branch %s into %s..." "$MARKER" "$1" "$2"
+  if [ $DRY_RUN -eq 0 ]; then
+    msg=$( eval "$cmd" 2>&1 )
+    validate_ret $? "$msg"
+  else
+    printf "\\n      %s\\n" "${IWTH}$cmd${CNRM}"
+  fi
+}
+
+# Pull the given branch name.
+function merge_branch_origin
+{
+  local cmd="git merge --ff-only origin/$1"
+  printf "  %s Merging branch origin/%s..." "$MARKER" "$1"
+  if [ $DRY_RUN -eq 0 ]; then
+    msg=$( eval "$cmd" 2>&1 )
+    validate_ret $? "$msg"
+  else
+    printf "\\n      %s\\n" "${IWTH}$cmd${CNRM}"
+  fi
+}
+
+# Go into the worktree repository.
+function goto_repo
+{
+  if [ ! -d "$1" ]; then
+    echo "  $1: Not found. Stopping."
+    exit 1
+  fi
+  cd "$1" || exit
+}
+
+# Fetch the origin. No arguments.
+function fetch_origin
+{
+  local cmd="git fetch origin"
+  printf "  %s Fetching origin..." "$MARKER"
+  if [ $DRY_RUN -eq 0 ]; then
+    msg=$( eval "$cmd" 2>&1 )
+    validate_ret $? "$msg"
+  else
+    printf "\\n      %s\\n" "${IWTH}$cmd${CNRM}"
+  fi
+}
+
+###############
+# Entry point #
+###############
+
+while getopts "n" opt; do
+  case "$opt" in
+    n) DRY_RUN=1
+       echo "    *** DRY DRUN MODE ***"
+       ;;
+    *)
+       ;;
+  esac
+done
+
+# First, fetch the origin.
+goto_repo "$ORIGIN_PATH"
+fetch_origin
+
+# Go over all configured worktree.
+for ((i=0; i<COUNT; i++)); do
+  current=${!WORKTREE[$i]:0:1}
+  previous=${!WORKTREE[$i]:1:1}
+  repo_path=${!WORKTREE[$i]:2:1}
+
+  printf "%s Handling branch \\n" "$MARKER" "${BYEL}$current${CNRM}"
+
+  # Go into the worktree to start merging.
+  goto_repo "$repo_path"
+  # Checkout the current branch
+  switch_branch "$current"
+  # Update the current branch with an origin merge to get the latest.
+  merge_branch_origin "$current"
+  # Merge the previous branch. Ex: merge maint-0.2.5 into maint-0.2.9.
+  merge_branch "$previous" "$current"
+done
diff --git a/scripts/git/git-pull-all.sh b/scripts/git/git-pull-all.sh
new file mode 100755
index 000000000..5d1d58e4b
--- /dev/null
+++ b/scripts/git/git-pull-all.sh
@@ -0,0 +1,224 @@
+#!/bin/bash
+
+##################################
+# User configuration (change me) #
+##################################
+
+# The general setup that is suggested here is:
+#
+#   GIT_PATH = /home/<user>/git/
+#     ... where the git repository directories resides.
+#   TOR_MASTER_NAME = "tor"
+#     ... which means that tor.git was cloned in /home/<user>/git/tor
+#   TOR_WKT_NAME = "tor-wkt"
+#     ... which means that the tor worktrees are in /home/<user>/git/tor-wkt
+
+# Where are all those git repositories?
+GIT_PATH="FULL_PATH_TO_GIT_REPOSITORY_DIRECTORY"
+# The tor master git repository directory from which all the worktree have
+# been created.
+TOR_MASTER_NAME="tor"
+# The worktrees location (directory).
+TOR_WKT_NAME="tor-wkt"
+
+#########################
+# End of configuration. #
+#########################
+
+# Configuration of the branches that needs merging. The values are in order:
+#   (1) Branch name to pull (update).
+#   (2) Full path of the git worktree.
+#
+# As an example:
+#   $ cd <PATH/TO/WORKTREE> (3)
+#   $ git checkout maint-0.3.5 (1)
+#   $ git pull
+#
+# First set of arrays are the maint-* branch and then the release-* branch.
+# New arrays need to be in the WORKTREE= array else they aren't considered.
+MAINT_029=( "maint-0.2.9" "$GIT_PATH/$TOR_WKT_NAME/maint-0.2.9" )
+MAINT_034=( "maint-0.3.4" "$GIT_PATH/$TOR_WKT_NAME/maint-0.3.4" )
+MAINT_035=( "maint-0.3.5" "$GIT_PATH/$TOR_WKT_NAME/maint-0.3.5" )
+MAINT_040=( "maint-0.4.0" "$GIT_PATH/$TOR_WKT_NAME/maint-0.4.0" )
+MAINT_MASTER=( "master" "$GIT_PATH/$TOR_MASTER_NAME" )
+
+RELEASE_029=( "release-0.2.9" "$GIT_PATH/$TOR_WKT_NAME/release-0.2.9" )
+RELEASE_034=( "release-0.3.4" "$GIT_PATH/$TOR_WKT_NAME/release-0.3.4" )
+RELEASE_035=( "release-0.3.5" "$GIT_PATH/$TOR_WKT_NAME/release-0.3.5" )
+RELEASE_040=( "release-0.4.0" "$GIT_PATH/$TOR_WKT_NAME/release-0.4.0" )
+
+# The master branch path has to be the main repository thus contains the
+# origin that will be used to fetch the updates. All the worktrees are created
+# from that repository.
+ORIGIN_PATH="$GIT_PATH/$TOR_MASTER_NAME"
+
+# SC2034 -- shellcheck thinks that these are unused.  We know better.
+ACTUALLY_THESE_ARE_USED=<<EOF
+${MAINT_029[0]}
+${MAINT_034[0]}
+${MAINT_035[0]}
+${MAINT_040[0]}
+${MAINT_MASTER[0]}
+${RELEASE_029[0]}
+${RELEASE_034[0]}
+${RELEASE_035[0]}
+${RELEASE_040[0]}
+EOF
+
+##########################
+# Git Worktree to manage #
+##########################
+
+# List of all worktrees to work on. All defined above. Ordering is important.
+# Always the maint-* branch first then the release-*.
+WORKTREE=(
+  MAINT_029[@]
+  RELEASE_029[@]
+
+  MAINT_034[@]
+  RELEASE_034[@]
+
+  MAINT_035[@]
+  RELEASE_035[@]
+
+  MAINT_040[@]
+  RELEASE_040[@]
+
+  MAINT_MASTER[@]
+)
+COUNT=${#WORKTREE[@]}
+
+# Controlled by the -n option. The dry run option will just output the command
+# that would have been executed for each worktree.
+DRY_RUN=0
+
+# Control characters
+CNRM=$'\x1b[0;0m'   # Clear color
+
+# Bright color
+BGRN=$'\x1b[1;32m'
+BBLU=$'\x1b[1;34m'
+BRED=$'\x1b[1;31m'
+BYEL=$'\x1b[1;33m'
+IWTH=$'\x1b[3;37m'
+
+# Strings for the pretty print.
+MARKER="${BBLU}[${BGRN}+${BBLU}]${CNRM}"
+SUCCESS="${BGRN}ok${CNRM}"
+FAILED="${BRED}failed${CNRM}"
+
+####################
+# Helper functions #
+####################
+
+# Validate the given returned value (error code), print success or failed. The
+# second argument is the error output in case of failure, it is printed out.
+# On failure, this function exits.
+function validate_ret
+{
+  if [ "$1" -eq 0 ]; then
+    printf "%s\\n" "$SUCCESS"
+  else
+    printf "%s\\n" "$FAILED"
+    printf "    %s" "$2"
+    exit 1
+  fi
+}
+
+# Switch to the given branch name.
+function switch_branch
+{
+  local cmd="git checkout $1"
+  printf "  %s Switching branch to %s..." "$MARKER" "$1"
+  if [ $DRY_RUN -eq 0 ]; then
+    msg=$( eval "$cmd" 2>&1 )
+    validate_ret $? "$msg"
+  else
+    printf "\\n      %s\\n" "${IWTH}$cmd${CNRM}"
+  fi
+}
+
+# Pull the given branch name.
+function merge_branch
+{
+  local cmd="git merge --ff-only origin/$1"
+  printf "  %s Merging branch origin/%s..." "$MARKER" "$1"
+  if [ $DRY_RUN -eq 0 ]; then
+    msg=$( eval "$cmd" 2>&1 )
+    validate_ret $? "$msg"
+  else
+    printf "\\n      %s\\n" "${IWTH}$cmd${CNRM}"
+  fi
+}
+
+# Go into the worktree repository.
+function goto_repo
+{
+  if [ ! -d "$1" ]; then
+    echo "  $1: Not found. Stopping."
+    exit 1
+  fi
+  cd "$1" || exit
+}
+
+# Fetch the origin. No arguments.
+function fetch_origin
+{
+  local cmd="git fetch origin"
+  printf "  %s Fetching origin..." "$MARKER"
+  if [ $DRY_RUN -eq 0 ]; then
+    msg=$( eval "$cmd" 2>&1 )
+    validate_ret $? "$msg"
+  else
+    printf "\\n      %s\\n" "${IWTH}$cmd${CNRM}"
+  fi
+}
+
+# Fetch tor-github pull requests. No arguments.
+function fetch_tor_github
+{
+  local cmd="git fetch tor-github"
+  printf "  %s Fetching tor-github..." "$MARKER"
+  if [ $DRY_RUN -eq 0 ]; then
+    msg=$( eval "$cmd" 2>&1 )
+    validate_ret $? "$msg"
+  else
+    printf "\\n      %s\\n" "${IWTH}$cmd${CNRM}"
+  fi
+}
+
+###############
+# Entry point #
+###############
+
+while getopts "n" opt; do
+  case "$opt" in
+    n) DRY_RUN=1
+       echo "    *** DRY DRUN MODE ***"
+       ;;
+    *)
+       ;;
+  esac
+done
+
+# First, fetch tor-github.
+goto_repo "$ORIGIN_PATH"
+fetch_tor_github
+
+# Then, fetch the origin.
+fetch_origin
+
+# Go over all configured worktree.
+for ((i=0; i<COUNT; i++)); do
+  current=${!WORKTREE[$i]:0:1}
+  repo_path=${!WORKTREE[$i]:1:1}
+
+  printf "%s Handling branch %s\\n" "$MARKER" "${BYEL}$current${CNRM}"
+
+  # Go into the worktree to start merging.
+  goto_repo "$repo_path"
+  # Checkout the current branch
+  switch_branch "$current"
+  # Update the current branch by merging the origin to get the latest.
+  merge_branch "$current"
+done
diff --git a/scripts/git/git-push-all.sh b/scripts/git/git-push-all.sh
new file mode 100755
index 000000000..0ce951d4b
--- /dev/null
+++ b/scripts/git/git-push-all.sh
@@ -0,0 +1,11 @@
+#!/bin/bash
+
+# The remote upstream branch on which git.torproject.org/tor.git points to.
+UPSTREAM_BRANCH="upstream"
+
+git push $UPSTREAM_BRANCH \
+   master \
+   {release,maint}-0.4.0 \
+   {release,maint}-0.3.5 \
+   {release,maint}-0.3.4 \
+   {release,maint}-0.2.9
diff --git a/scripts/git/post-merge.git-hook b/scripts/git/post-merge.git-hook
new file mode 100755
index 000000000..176b7c9bb
--- /dev/null
+++ b/scripts/git/post-merge.git-hook
@@ -0,0 +1,45 @@
+#!/bin/sh
+
+# This is post-merge git hook script to check for changes in:
+# * git hook scripts
+# * helper scripts for using git efficiently.
+# If any changes are detected, a diff of them is printed.
+#
+# To install this script, copy it to .git/hooks/post-merge in local copy of
+# tor git repo and make sure it has permission to execute.
+
+git_toplevel=$(git rev-parse --show-toplevel)
+
+check_for_diffs() {
+        installed="$git_toplevel/.git/hooks/$1"
+        latest="$git_toplevel/scripts/git/$1.git-hook"
+
+        if [ -e "$installed" ]
+        then
+               if ! cmp "$installed" "$latest" >/dev/null 2>&1
+               then
+                        echo "ATTENTION: $1 hook has changed:"
+                        echo "==============================="
+                        diff -u "$installed" "$latest"
+               fi
+        fi
+}
+
+check_for_script_update() {
+        fullpath="$1"
+
+        if ! git diff ORIG_HEAD HEAD --exit-code -- "$fullpath" >/dev/null
+        then
+                echo "ATTENTION: $1 has changed:"
+                git --no-pager diff ORIG_HEAD HEAD -- "$fullpath"
+        fi
+}
+
+check_for_diffs "pre-push"
+check_for_diffs "pre-commit"
+check_for_diffs "post-merge"
+
+for file in "$git_toplevel"/scripts/git/* ; do
+        check_for_script_update "$file"
+done
+
diff --git a/scripts/git/pre-commit.git-hook b/scripts/git/pre-commit.git-hook
new file mode 100755
index 000000000..b285776c0
--- /dev/null
+++ b/scripts/git/pre-commit.git-hook
@@ -0,0 +1,45 @@
+#!/bin/bash
+#
+# To install this script, copy it to .git/hooks/pre-commit in local copy of
+# tor git repo and make sure it has permission to execute.
+#
+# This is pre-commit git hook script that prevents commiting your changeset if
+# it fails our code formatting or changelog entry formatting checkers.
+
+workdir=$(git rev-parse --show-toplevel)
+
+cd "$workdir" || exit 1
+
+set -e
+
+if [ -n "$(ls ./changes/)" ]; then
+    python scripts/maint/lintChanges.py ./changes/*
+fi
+
+if [ -d src/lib ]; then
+    # This is the layout in 0.3.5
+    perl scripts/maint/checkSpace.pl -C \
+         src/lib/*/*.[ch] \
+         src/core/*/*.[ch] \
+         src/feature/*/*.[ch] \
+         src/app/*/*.[ch] \
+         src/test/*.[ch] \
+         src/test/*/*.[ch] \
+         src/tools/*.[ch]
+elif [ -d src/common ]; then
+    # This was the layout before 0.3.5
+    perl scripts/maint/checkSpace.pl -C \
+         src/common/*/*.[ch] \
+         src/or/*/*.[ch] \
+         src/test/*.[ch] \
+         src/test/*/*.[ch] \
+         src/tools/*.[ch]
+fi
+
+if test -e scripts/maint/checkIncludes.py; then
+    python scripts/maint/checkIncludes.py
+fi
+
+if [ -e scripts/maint/practracker/practracker.py ]; then
+  python3 ./scripts/maint/practracker/practracker.py "$workdir"
+fi
diff --git a/scripts/git/pre-push.git-hook b/scripts/git/pre-push.git-hook
new file mode 100755
index 000000000..c9e72a4d4
--- /dev/null
+++ b/scripts/git/pre-push.git-hook
@@ -0,0 +1,108 @@
+#!/bin/bash
+
+# git pre-push hook script to:
+# 1) prevent "fixup!" and "squash!" commit from ending up in master, release-*
+#    or maint-*
+# 2) Disallow pushing branches other than master, release-*
+#    and maint-* to origin (e.g. gitweb.torproject.org).
+#
+# To install this script, copy it into .git/hooks/pre-push path in your
+# local copy of git repository. Make sure it has permission to execute.
+# Furthermore, make sure that TOR_UPSTREAM_REMOTE_NAME environment
+# variable is set to local name of git remote that corresponds to upstream
+# repository on e.g. git.torproject.org.
+#
+# The following sample script was used as starting point:
+# https://github.com/git/git/blob/master/templates/hooks--pre-push.sample
+
+echo "Running pre-push hook"
+
+z40=0000000000000000000000000000000000000000
+
+upstream_name=${TOR_UPSTREAM_REMOTE_NAME:-"upstream"}
+
+workdir=$(git rev-parse --show-toplevel)
+if [ -x "$workdir/.git/hooks/pre-commit" ]; then
+  if ! "$workdir"/.git/hooks/pre-commit; then
+    exit 1
+  fi
+fi
+
+if [ -e scripts/maint/practracker/practracker.py ]; then
+  if ! python3 ./scripts/maint/practracker/practracker.py "$workdir"; then
+    exit 1
+  fi
+fi
+
+remote="$1"
+remote_loc="$2"
+
+remote_name=$(git remote --verbose | grep "$2" | awk '{print $1}' | head -n 1)
+
+if [[ "$remote_name" != "$upstream_name" ]]; then
+  echo "Not pushing to upstream - refraining from further checks"
+  exit 0
+fi
+
+ref_is_upstream_branch() {
+        if [ "$1" == "refs/heads/master" ] ||
+                [[ "$1" == refs/heads/release-* ]] ||
+                [[ "$1" == refs/heads/maint-* ]]
+        then
+                return 1
+        fi
+}
+
+# shellcheck disable=SC2034
+while read -r local_ref local_sha remote_ref remote_sha
+do
+	if [ "$local_sha" = $z40 ]
+	then
+		# Handle delete
+		:
+	else
+		if [ "$remote_sha" = $z40 ]
+		then
+			# New branch, examine all commits
+			range="$local_sha"
+		else
+			# Update to existing branch, examine new commits
+			range="$remote_sha..$local_sha"
+		fi
+
+                if (ref_is_upstream_branch "$local_ref" == 0 ||
+                        ref_is_upstream_branch "$remote_ref"  == 0) &&
+                        [ "$local_ref" != "$remote_ref" ]
+                then
+                        if [ "$remote" == "origin" ]
+                        then
+                                echo >&2 "Not pushing: $local_ref to $remote_ref"
+			        echo >&2 "If you really want to push this, use --no-verify."
+                                exit 1
+                        else
+                                continue
+                        fi
+                fi
+
+                # Check for fixup! commit
+                commit=$(git rev-list -n 1 --grep '^fixup!' "$range")
+		if [ -n "$commit" ]
+		then
+			echo >&2 "Found fixup! commit in $local_ref, not pushing"
+			echo >&2 "If you really want to push this, use --no-verify."
+			exit 1
+		fi
+
+                # Check for squash! commit
+                commit=$(git rev-list -n 1 --grep '^squash!' "$range")
+		if [ -n "$commit" ]
+		then
+			echo >&2 "Found squash! commit in $local_ref, not pushing"
+			echo >&2 "If you really want to push this, use --no-verify."
+			exit 1
+		fi
+	fi
+done
+
+exit 0
+
diff --git a/scripts/maint/add_c_file.py b/scripts/maint/add_c_file.py
new file mode 100755
index 000000000..499415974
--- /dev/null
+++ b/scripts/maint/add_c_file.py
@@ -0,0 +1,251 @@
+#!/usr/bin/env python3
+
+"""
+   Add a C file with matching header to the Tor codebase.  Creates
+   both files from templates, and adds them to the right include.am file.
+
+   Example usage:
+
+   % add_c_file.py ./src/feature/dirauth/ocelot.c
+"""
+
+import os
+import re
+import time
+
+def topdir_file(name):
+    """Strip opening "src" from a filename"""
+    if name.startswith("src/"):
+        name = name[4:]
+    return name
+
+def guard_macro(name):
+    """Return the guard macro that should be used for the header file 'name'.
+    """
+    td = topdir_file(name).replace(".", "_").replace("/", "_").upper()
+    return "TOR_{}".format(td)
+
+def makeext(name, new_extension):
+    """Replace the extension for the file called 'name' with 'new_extension'.
+    """
+    base = os.path.splitext(name)[0]
+    return base + "." + new_extension
+
+def instantiate_template(template, output_fname):
+    """
+    Fill in a template with string using the fields that should be used
+    for 'output_fname'.
+    """
+    names = {
+        # The relative location of the header file.
+        'header_path' : makeext(topdir_file(output_fname), "h"),
+        # The relative location of the C file file.
+        'c_file_path' : makeext(topdir_file(output_fname), "c"),
+        # The truncated name of the file.
+        'short_name' : os.path.basename(output_fname),
+        # The current year, for the copyright notice
+        'this_year' : time.localtime().tm_year,
+        # An appropriate guard macro, for the header.
+        'guard_macro' : guard_macro(output_fname),
+    }
+
+    return template.format(**names)
+
+HEADER_TEMPLATE = """\
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-{this_year}, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file {short_name}
+ * @brief Header for {c_file_path}
+ **/
+
+#ifndef {guard_macro}
+#define {guard_macro}
+
+#endif /* !defined({guard_macro}) */
+"""
+
+C_FILE_TEMPLATE = """\
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-{this_year}, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file {short_name}
+ * @brief DOCDOC
+ **/
+
+#include "orconfig.h"
+#include "{header_path}"
+"""
+
+class AutomakeChunk:
+    """
+    Represents part of an automake file.  If it is decorated with
+    an ADD_C_FILE comment, it has a "kind" based on what to add to it.
+    Otherwise, it only has a bunch of lines in it.
+    """
+    pat = re.compile(r'# ADD_C_FILE: INSERT (\S*) HERE', re.I)
+
+    def __init__(self):
+        self.lines = []
+        self.kind = ""
+
+    def addLine(self, line):
+        """
+        Insert a line into this chunk while parsing the automake file.
+        """
+        m = self.pat.match(line)
+        if m:
+            if self.lines:
+                raise ValueError("control line not preceded by a blank line")
+            self.kind = m.group(1)
+
+        self.lines.append(line)
+        if line.strip() == "":
+            return True
+
+        return False
+
+    def insertMember(self, member):
+        """
+        Add a new member to this chunk.  Try to insert it in alphabetical
+        order with matching indentation, but don't freak out too much if the
+        source isn't consistent.
+
+        Assumes that this chunk is of the form:
+           FOOBAR = \
+              X     \
+              Y     \
+              Z
+        """
+        self.prespace = "\t"
+        self.postspace = "\t\t"
+        for lineno, line in enumerate(self.lines):
+            m = re.match(r'(\s+)(\S+)(\s+)\\', line)
+            if not m:
+                continue
+            prespace, fname, postspace = m.groups()
+            if fname > member:
+                self.insert_before(lineno, member, prespace, postspace)
+                return
+        self.insert_at_end(member)
+
+    def insert_before(self, lineno, member, prespace, postspace):
+        self.lines.insert(lineno,
+                          "{}{}{}\\\n".format(prespace, member, postspace))
+
+    def insert_at_end(self, member, prespace, postspace):
+        lastline = self.lines[-1]
+        self.lines[-1] += '{}\\\n'.format(postspace)
+        self.lines.append("{}{}\n".format(prespace, member))
+
+    def dump(self, f):
+        """Write all the lines in this chunk to the file 'f'."""
+        for line in self.lines:
+            f.write(line)
+            if not line.endswith("\n"):
+                f.write("\n")
+
+class ParsedAutomake:
+    """A sort-of-parsed automake file, with identified chunks into which
+       headers and c files can be inserted.
+    """
+    def __init__(self):
+        self.chunks = []
+        self.by_type = {}
+
+    def addChunk(self, chunk):
+        """Add a newly parsed AutomakeChunk to this file."""
+        self.chunks.append(chunk)
+        self.by_type[chunk.kind.lower()] = chunk
+
+    def add_file(self, fname, kind):
+        """Insert a file of kind 'kind' to the appropriate section of this
+           file. Return True if we added it.
+        """
+        if kind.lower() in self.by_type:
+            self.by_type[kind.lower()].insertMember(fname)
+            return True
+        else:
+            return False
+
+    def dump(self, f):
+        """Write this file into a file 'f'."""
+        for chunk in self.chunks:
+            chunk.dump(f)
+
+def get_include_am_location(fname):
+    """Find the right include.am file for introducing a new file.  Return None
+       if we can't guess one.
+
+       Note that this function is imperfect because our include.am layout is
+       not (yet) consistent.
+    """
+    td = topdir_file(fname)
+    m = re.match(r'^lib/([a-z0-9_]*)/', td)
+    if m:
+        return "src/lib/{}/include.am".format(m.group(1))
+
+    if re.match(r'^(core|feature|app)/', td):
+        return "src/core/include.am"
+
+    if re.match(r'^test/', td):
+        return "src/test/include.am"
+
+    return None
+
+def run(fn):
+    """
+    Create a new C file and H file corresponding to the filename "fn", and
+    add them to include.am.
+    """
+
+    cf = makeext(fn, "c")
+    hf = makeext(fn, "h")
+
+    if os.path.exists(cf):
+        print("{} already exists".format(cf))
+        return 1
+    if os.path.exists(hf):
+        print("{} already exists".format(hf))
+        return 1
+
+    with open(cf, 'w') as f:
+        f.write(instantiate_template(C_FILE_TEMPLATE, cf))
+
+    with open(hf, 'w') as f:
+        f.write(instantiate_template(HEADER_TEMPLATE, hf))
+
+    iam = get_include_am_location(cf)
+    if iam is None or not os.path.exists(iam):
+        print("Made files successfully but couldn't identify include.am for {}"
+              .format(cf))
+        return 1
+
+    amfile = ParsedAutomake()
+    cur_chunk = AutomakeChunk()
+    with open(iam) as f:
+        for line in f:
+            if cur_chunk.addLine(line):
+                amfile.addChunk(cur_chunk)
+                cur_chunk = AutomakeChunk()
+        amfile.addChunk(cur_chunk)
+
+    amfile.add_file(cf, "sources")
+    amfile.add_file(hf, "headers")
+
+    with open(iam+".tmp", 'w') as f:
+        amfile.dump(f)
+
+    os.rename(iam+".tmp", iam)
+
+if __name__ == '__main__':
+    import sys
+    sys.exit(run(sys.argv[1]))
diff --git a/scripts/maint/checkIncludes.py b/scripts/maint/checkIncludes.py
index 3afd9bbeb..ec9350b9b 100755
--- a/scripts/maint/checkIncludes.py
+++ b/scripts/maint/checkIncludes.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/python
 # Copyright 2018 The Tor Project, Inc.  See LICENSE file for licensing info.
 
 """This script looks through all the directories for files matching *.c or
diff --git a/scripts/maint/checkSpace.pl b/scripts/maint/checkSpace.pl
index 633b47e31..433ae6280 100755
--- a/scripts/maint/checkSpace.pl
+++ b/scripts/maint/checkSpace.pl
@@ -18,6 +18,8 @@ if ($ARGV[0] =~ /^-/) {
 
 our %basenames = ();
 
+our %guardnames = ();
+
 for my $fn (@ARGV) {
     open(F, "$fn");
     my $lastnil = 0;
@@ -31,6 +33,10 @@ for my $fn (@ARGV) {
     } else {
         $basenames{$basename} = $fn;
     }
+    my $isheader = ($fn =~ /\.h/);
+    my $seenguard = 0;
+    my $guardname = "<none>";
+
     while (<F>) {
         ## Warn about windows-style newlines.
         #    (We insist on lines that end with a single LF character, not
@@ -112,6 +118,23 @@ for my $fn (@ARGV) {
                     next;
                 }
             }
+
+            if ($isheader) {
+                if ($seenguard == 0) {
+                    if (/ifndef\s+(\S+)/) {
+                        ++$seenguard;
+                        $guardname = $1;
+                    }
+                } elsif ($seenguard == 1) {
+                    if (/^\#define (\S+)/) {
+                        ++$seenguard;
+                        if ($1 ne $guardname) {
+                            msg "GUARD:$fn:$.: Header guard macro mismatch.\n";
+                        }
+                    }
+                }
+            }
+
             if (m!/\*.*?\*/!) {
                 s!\s*/\*.*?\*/!!;
             } elsif (m!/\*!) {
@@ -201,6 +224,15 @@ for my $fn (@ARGV) {
             }
         }
     }
+    if ($isheader && $C) {
+        if ($seenguard < 2) {
+            msg "$fn:No #ifndef/#define header guard pair found.\n";
+        } elsif ($guardnames{$guardname}) {
+            msg "$fn:Guard macro $guardname also used in $guardnames{$guardname}\n";
+        } else {
+            $guardnames{$guardname} = $fn;
+        }
+    }
     close(F);
 }
 
diff --git a/scripts/maint/practracker/exceptions.txt b/scripts/maint/practracker/exceptions.txt
new file mode 100644
index 000000000..726dc9c3e
--- /dev/null
+++ b/scripts/maint/practracker/exceptions.txt
@@ -0,0 +1,289 @@
+# Welcome to the exceptions file for Tor's best-practices tracker!
+#
+# Each line of this file represents a single violation of Tor's best
+# practices -- typically, a violation that we had before practracker.py
+# first existed.
+#
+# There are three kinds of problems that we recognize right now:
+#   function-size -- a function of more than 100 lines.
+#   file-size -- a file of more than 3000 lines.
+#   include-count -- a file with more than 50 #includes.
+#
+# Each line below represents a single exception that practracker should
+# _ignore_. Each line has four parts:
+#  1. The word "problem".
+#  2. The kind of problem.
+#  3. The location of the problem: either a filename, or a
+#     filename:functionname pair.
+#  4. The magnitude of the problem to ignore.
+#
+# So for example, consider this line:
+#    problem file-size /src/core/or/connection_or.c 3200
+#
+# It tells practracker to allow the mentioned file to be up to 3200 lines
+# long, even though ordinarily it would warn about any file with more than
+# 3000 lines.
+#
+# You can either edit this file by hand, or regenerate it completely by
+# running `make practracker-regen`.
+#
+# Remember: It is better to fix the problem than to add a new exception!
+
+problem file-size /src/app/config/config.c 8518
+problem include-count /src/app/config/config.c 87
+problem function-size /src/app/config/config.c:options_act_reversible() 296
+problem function-size /src/app/config/config.c:options_act() 589
+problem function-size /src/app/config/config.c:resolve_my_address() 192
+problem function-size /src/app/config/config.c:options_validate() 1217
+problem function-size /src/app/config/config.c:options_init_from_torrc() 207
+problem function-size /src/app/config/config.c:options_init_from_string() 173
+problem function-size /src/app/config/config.c:options_init_logs() 146
+problem function-size /src/app/config/config.c:parse_bridge_line() 104
+problem function-size /src/app/config/config.c:parse_transport_line() 191
+problem function-size /src/app/config/config.c:parse_dir_authority_line() 151
+problem function-size /src/app/config/config.c:parse_dir_fallback_line() 102
+problem function-size /src/app/config/config.c:parse_port_config() 452
+problem function-size /src/app/config/config.c:parse_ports() 170
+problem function-size /src/app/config/config.c:getinfo_helper_config() 116
+problem function-size /src/app/config/confparse.c:config_assign_value() 205
+problem function-size /src/app/config/confparse.c:config_get_assigned_option() 129
+problem include-count /src/app/main/main.c 67
+problem function-size /src/app/main/main.c:dumpstats() 102
+problem function-size /src/app/main/main.c:tor_init() 137
+problem function-size /src/app/main/main.c:sandbox_init_filter() 291
+problem function-size /src/app/main/main.c:run_tor_main_loop() 105
+problem function-size /src/app/main/ntmain.c:nt_service_install() 125
+problem file-size /src/core/mainloop/connection.c 5569
+problem include-count /src/core/mainloop/connection.c 62
+problem function-size /src/core/mainloop/connection.c:connection_free_minimal() 185
+problem function-size /src/core/mainloop/connection.c:connection_listener_new() 328
+problem function-size /src/core/mainloop/connection.c:connection_handle_listener_read() 161
+problem function-size /src/core/mainloop/connection.c:connection_connect_sockaddr() 103
+problem function-size /src/core/mainloop/connection.c:connection_proxy_connect() 148
+problem function-size /src/core/mainloop/connection.c:connection_read_proxy_handshake() 153
+problem function-size /src/core/mainloop/connection.c:retry_listener_ports() 116
+problem function-size /src/core/mainloop/connection.c:connection_handle_read_impl() 111
+problem function-size /src/core/mainloop/connection.c:connection_buf_read_from_socket() 181
+problem function-size /src/core/mainloop/connection.c:connection_handle_write_impl() 241
+problem function-size /src/core/mainloop/connection.c:assert_connection_ok() 143
+problem include-count /src/core/mainloop/mainloop.c 63
+problem function-size /src/core/mainloop/mainloop.c:conn_close_if_marked() 108
+problem function-size /src/core/mainloop/mainloop.c:run_connection_housekeeping() 123
+problem file-size /src/core/or/channel.c 3487
+problem function-size /src/core/or/channeltls.c:channel_tls_handle_var_cell() 160
+problem function-size /src/core/or/channeltls.c:channel_tls_process_versions_cell() 170
+problem function-size /src/core/or/channeltls.c:channel_tls_process_netinfo_cell() 214
+problem function-size /src/core/or/channeltls.c:channel_tls_process_certs_cell() 246
+problem function-size /src/core/or/channeltls.c:channel_tls_process_authenticate_cell() 202
+problem include-count /src/core/or/circuitbuild.c 54
+problem function-size /src/core/or/circuitbuild.c:get_unique_circ_id_by_chan() 128
+problem function-size /src/core/or/circuitbuild.c:circuit_extend() 147
+problem function-size /src/core/or/circuitbuild.c:choose_good_exit_server_general() 206
+problem include-count /src/core/or/circuitlist.c 55
+problem function-size /src/core/or/circuitlist.c:HT_PROTOTYPE() 128
+problem function-size /src/core/or/circuitlist.c:circuit_free_() 143
+problem function-size /src/core/or/circuitlist.c:circuit_find_to_cannibalize() 102
+problem function-size /src/core/or/circuitlist.c:circuit_about_to_free() 120
+problem function-size /src/core/or/circuitlist.c:circuits_handle_oom() 117
+problem function-size /src/core/or/circuitmux.c:circuitmux_set_policy() 110
+problem function-size /src/core/or/circuitmux.c:circuitmux_attach_circuit() 114
+problem file-size /src/core/or/circuitpadding.c 3040
+problem function-size /src/core/or/circuitpadding.c:circpad_machine_schedule_padding() 107
+problem function-size /src/core/or/circuitpadding.c:circpad_machine_schedule_padding() 113 
+problem function-size /src/core/or/circuitpadding_machines.c:circpad_machine_relay_hide_intro_circuits() 104
+problem function-size /src/core/or/circuitpadding_machines.c:circpad_machine_client_hide_rend_circuits() 112
+problem function-size /src/core/or/circuitstats.c:circuit_build_times_parse_state() 124
+problem file-size /src/core/or/circuituse.c 3162
+problem function-size /src/core/or/circuituse.c:circuit_is_acceptable() 132
+problem function-size /src/core/or/circuituse.c:circuit_expire_building() 394
+problem function-size /src/core/or/circuituse.c:circuit_log_ancient_one_hop_circuits() 126
+problem function-size /src/core/or/circuituse.c:circuit_build_failed() 149
+problem function-size /src/core/or/circuituse.c:circuit_launch_by_extend_info() 110
+problem function-size /src/core/or/circuituse.c:circuit_get_open_circ_or_launch() 354
+problem function-size /src/core/or/circuituse.c:connection_ap_handshake_attach_circuit() 244
+problem function-size /src/core/or/command.c:command_process_create_cell() 156
+problem function-size /src/core/or/command.c:command_process_relay_cell() 132
+problem file-size /src/core/or/connection_edge.c 4595
+problem include-count /src/core/or/connection_edge.c 65
+problem function-size /src/core/or/connection_edge.c:connection_ap_expire_beginning() 117
+problem function-size /src/core/or/connection_edge.c:connection_ap_handshake_rewrite() 192
+problem function-size /src/core/or/connection_edge.c:connection_ap_handle_onion() 188
+problem function-size /src/core/or/connection_edge.c:connection_ap_handshake_rewrite_and_attach() 423
+problem function-size /src/core/or/connection_edge.c:connection_ap_handshake_send_begin() 111
+problem function-size /src/core/or/connection_edge.c:connection_ap_handshake_socks_resolved() 106
+problem function-size /src/core/or/connection_edge.c:connection_exit_begin_conn() 184
+problem function-size /src/core/or/connection_edge.c:connection_exit_connect() 102
+problem file-size /src/core/or/connection_or.c 3124
+problem include-count /src/core/or/connection_or.c 51
+problem function-size /src/core/or/connection_or.c:connection_or_group_set_badness_() 105
+problem function-size /src/core/or/connection_or.c:connection_or_client_learned_peer_id() 144
+problem function-size /src/core/or/connection_or.c:connection_or_compute_authenticate_cell_body() 235
+problem file-size /src/core/or/policies.c 3249
+problem function-size /src/core/or/policies.c:policy_summarize() 107
+problem function-size /src/core/or/protover.c:protover_all_supported() 117
+problem file-size /src/core/or/relay.c 3244
+problem function-size /src/core/or/relay.c:circuit_receive_relay_cell() 127
+problem function-size /src/core/or/relay.c:relay_send_command_from_edge_() 112
+problem function-size /src/core/or/relay.c:connection_ap_process_end_not_open() 194
+problem function-size /src/core/or/relay.c:connection_edge_process_relay_cell_not_open() 139
+problem function-size /src/core/or/relay.c:connection_edge_process_relay_cell() 430
+problem function-size /src/core/or/relay.c:connection_edge_package_raw_inbuf() 129
+problem function-size /src/core/or/relay.c:circuit_resume_edge_reading_helper() 148
+problem function-size /src/core/or/scheduler_kist.c:kist_scheduler_run() 171
+problem function-size /src/core/or/scheduler_vanilla.c:vanilla_scheduler_run() 109
+problem function-size /src/core/or/versions.c:tor_version_parse() 104
+problem function-size /src/core/proto/proto_socks.c:parse_socks_client() 112
+problem function-size /src/feature/client/addressmap.c:addressmap_rewrite() 112
+problem function-size /src/feature/client/bridges.c:rewrite_node_address_for_bridge() 126
+problem function-size /src/feature/client/circpathbias.c:pathbias_measure_close_rate() 108
+problem function-size /src/feature/client/dnsserv.c:evdns_server_callback() 153
+problem file-size /src/feature/client/entrynodes.c 3824
+problem function-size /src/feature/client/entrynodes.c:entry_guards_upgrade_waiting_circuits() 157
+problem function-size /src/feature/client/entrynodes.c:entry_guard_parse_from_state() 246
+problem function-size /src/feature/client/transports.c:handle_proxy_line() 108
+problem function-size /src/feature/client/transports.c:parse_method_line_helper() 112
+problem function-size /src/feature/client/transports.c:create_managed_proxy_environment() 109
+problem function-size /src/feature/control/control.c:connection_control_process_inbuf() 136
+problem function-size /src/feature/control/control_auth.c:handle_control_authchallenge() 103
+problem function-size /src/feature/control/control_auth.c:handle_control_authenticate() 187
+problem function-size /src/feature/control/control_cmd.c:handle_control_extendcircuit() 151
+problem function-size /src/feature/control/control_cmd.c:handle_control_add_onion() 269
+problem function-size /src/feature/control/control_cmd.c:add_onion_helper_keyarg() 125
+problem function-size /src/feature/control/control_events.c:control_event_stream_status() 119
+problem include-count /src/feature/control/control_getinfo.c 54
+problem function-size /src/feature/control/control_getinfo.c:getinfo_helper_misc() 109
+problem function-size /src/feature/control/control_getinfo.c:getinfo_helper_dir() 304
+problem function-size /src/feature/control/control_getinfo.c:getinfo_helper_events() 236
+problem function-size /src/feature/dirauth/bwauth.c:dirserv_read_measured_bandwidths() 124
+problem file-size /src/feature/dirauth/dirvote.c 4726
+problem include-count /src/feature/dirauth/dirvote.c 53
+problem function-size /src/feature/dirauth/dirvote.c:format_networkstatus_vote() 249
+problem function-size /src/feature/dirauth/dirvote.c:networkstatus_compute_bw_weights_v10() 235
+problem function-size /src/feature/dirauth/dirvote.c:networkstatus_compute_consensus() 962
+problem function-size /src/feature/dirauth/dirvote.c:networkstatus_add_detached_signatures() 123
+problem function-size /src/feature/dirauth/dirvote.c:dirvote_add_vote() 162
+problem function-size /src/feature/dirauth/dirvote.c:dirvote_compute_consensuses() 164
+problem function-size /src/feature/dirauth/dirvote.c:dirserv_generate_networkstatus_vote_obj() 293
+problem function-size /src/feature/dirauth/dsigs_parse.c:networkstatus_parse_detached_signatures() 196
+problem function-size /src/feature/dirauth/guardfraction.c:dirserv_read_guardfraction_file_from_str() 110
+problem function-size /src/feature/dirauth/process_descs.c:dirserv_add_descriptor() 125
+problem function-size /src/feature/dirauth/shared_random.c:should_keep_commit() 110
+problem function-size /src/feature/dirauth/voteflags.c:dirserv_compute_performance_thresholds() 172
+problem function-size /src/feature/dircache/consdiffmgr.c:consdiffmgr_cleanup() 115
+problem function-size /src/feature/dircache/consdiffmgr.c:consdiffmgr_rescan_flavor_() 111
+problem function-size /src/feature/dircache/consdiffmgr.c:consensus_diff_worker_threadfn() 132
+problem function-size /src/feature/dircache/dircache.c:handle_get_current_consensus() 166
+problem function-size /src/feature/dircache/dircache.c:directory_handle_command_post() 120
+problem file-size /src/feature/dirclient/dirclient.c 3215
+problem include-count /src/feature/dirclient/dirclient.c 51
+problem function-size /src/feature/dirclient/dirclient.c:directory_get_from_dirserver() 131
+problem function-size /src/feature/dirclient/dirclient.c:directory_initiate_request() 201
+problem function-size /src/feature/dirclient/dirclient.c:directory_send_command() 241
+problem function-size /src/feature/dirclient/dirclient.c:dir_client_decompress_response_body() 114
+problem function-size /src/feature/dirclient/dirclient.c:connection_dir_client_reached_eof() 189
+problem function-size /src/feature/dirclient/dirclient.c:handle_response_fetch_consensus() 105
+problem function-size /src/feature/dircommon/consdiff.c:gen_ed_diff() 204
+problem function-size /src/feature/dircommon/consdiff.c:apply_ed_diff() 159
+problem function-size /src/feature/dirparse/authcert_parse.c:authority_cert_parse_from_string() 182
+problem function-size /src/feature/dirparse/microdesc_parse.c:microdescs_parse_from_string() 169
+problem function-size /src/feature/dirparse/ns_parse.c:routerstatus_parse_entry_from_string() 286
+problem function-size /src/feature/dirparse/ns_parse.c:networkstatus_verify_bw_weights() 389
+problem function-size /src/feature/dirparse/ns_parse.c:networkstatus_parse_vote_from_string() 638
+problem function-size /src/feature/dirparse/parsecommon.c:tokenize_string() 103
+problem function-size /src/feature/dirparse/parsecommon.c:get_next_token() 159
+problem function-size /src/feature/dirparse/routerparse.c:router_parse_entry_from_string() 557
+problem function-size /src/feature/dirparse/routerparse.c:extrainfo_parse_entry_from_string() 210
+problem function-size /src/feature/hibernate/hibernate.c:accounting_parse_options() 109
+problem function-size /src/feature/hs/hs_cell.c:hs_cell_build_establish_intro() 115
+problem function-size /src/feature/hs/hs_cell.c:hs_cell_parse_introduce2() 154
+problem function-size /src/feature/hs/hs_client.c:send_introduce1() 104
+problem function-size /src/feature/hs/hs_client.c:hs_config_client_authorization() 108
+problem function-size /src/feature/hs/hs_common.c:hs_get_responsible_hsdirs() 104
+problem function-size /src/feature/hs/hs_config.c:config_generic_service() 140
+problem function-size /src/feature/hs/hs_descriptor.c:desc_encode_v3() 104
+problem function-size /src/feature/hs/hs_descriptor.c:decrypt_desc_layer() 110
+problem function-size /src/feature/hs/hs_descriptor.c:decode_introduction_point() 122
+problem function-size /src/feature/hs/hs_descriptor.c:desc_decode_superencrypted_v3() 109
+problem function-size /src/feature/hs/hs_descriptor.c:desc_decode_encrypted_v3() 109
+problem file-size /src/feature/hs/hs_service.c 4109
+problem function-size /src/feature/keymgt/loadkey.c:ed_key_init_from_file() 333
+problem function-size /src/feature/nodelist/authcert.c:trusted_dirs_load_certs_from_string() 124
+problem function-size /src/feature/nodelist/authcert.c:authority_certs_fetch_missing() 296
+problem function-size /src/feature/nodelist/fmt_routerstatus.c:routerstatus_format_entry() 166
+problem function-size /src/feature/nodelist/microdesc.c:microdesc_cache_rebuild() 134
+problem include-count /src/feature/nodelist/networkstatus.c 62
+problem function-size /src/feature/nodelist/networkstatus.c:networkstatus_check_consensus_signature() 176
+problem function-size /src/feature/nodelist/networkstatus.c:networkstatus_set_current_consensus() 293
+problem function-size /src/feature/nodelist/node_select.c:router_pick_directory_server_impl() 123
+problem function-size /src/feature/nodelist/node_select.c:compute_weighted_bandwidths() 206
+problem function-size /src/feature/nodelist/node_select.c:router_pick_trusteddirserver_impl() 114
+problem function-size /src/feature/nodelist/nodelist.c:compute_frac_paths_available() 193
+problem file-size /src/feature/nodelist/routerlist.c 3238
+problem function-size /src/feature/nodelist/routerlist.c:router_rebuild_store() 148
+problem function-size /src/feature/nodelist/routerlist.c:router_add_to_routerlist() 169
+problem function-size /src/feature/nodelist/routerlist.c:routerlist_remove_old_routers() 121
+problem function-size /src/feature/nodelist/routerlist.c:update_consensus_router_descriptor_downloads() 136
+problem function-size /src/feature/nodelist/routerlist.c:update_extrainfo_downloads() 103
+problem function-size /src/feature/relay/dns.c:dns_resolve_impl() 134
+problem function-size /src/feature/relay/dns.c:configure_nameservers() 161
+problem function-size /src/feature/relay/dns.c:evdns_callback() 109
+problem file-size /src/feature/relay/router.c 3407
+problem include-count /src/feature/relay/router.c 56
+problem function-size /src/feature/relay/router.c:init_keys() 252
+problem function-size /src/feature/relay/router.c:get_my_declared_family() 114
+problem function-size /src/feature/relay/router.c:router_build_fresh_unsigned_routerinfo() 136
+problem function-size /src/feature/relay/router.c:router_dump_router_to_string() 371
+problem function-size /src/feature/relay/router.c:extrainfo_dump_to_string() 206
+problem function-size /src/feature/relay/routerkeys.c:load_ed_keys() 294
+problem function-size /src/feature/rend/rendcache.c:rend_cache_store_v2_desc_as_client() 193
+problem function-size /src/feature/rend/rendclient.c:rend_client_send_introduction() 220
+problem function-size /src/feature/rend/rendcommon.c:rend_encode_v2_descriptors() 225
+problem function-size /src/feature/rend/rendmid.c:rend_mid_establish_intro_legacy() 104
+problem function-size /src/feature/rend/rendparse.c:rend_parse_v2_service_descriptor() 187
+problem function-size /src/feature/rend/rendparse.c:rend_decrypt_introduction_points() 104
+problem function-size /src/feature/rend/rendparse.c:rend_parse_introduction_points() 131
+problem file-size /src/feature/rend/rendservice.c 4511
+problem function-size /src/feature/rend/rendservice.c:rend_service_prune_list_impl_() 107
+problem function-size /src/feature/rend/rendservice.c:rend_config_service() 164
+problem function-size /src/feature/rend/rendservice.c:rend_service_load_auth_keys() 178
+problem function-size /src/feature/rend/rendservice.c:rend_service_receive_introduction() 332
+problem function-size /src/feature/rend/rendservice.c:rend_service_parse_intro_for_v3() 115
+problem function-size /src/feature/rend/rendservice.c:rend_service_decrypt_intro() 115
+problem function-size /src/feature/rend/rendservice.c:rend_service_intro_has_opened() 126
+problem function-size /src/feature/rend/rendservice.c:rend_service_rendezvous_has_opened() 117
+problem function-size /src/feature/rend/rendservice.c:directory_post_to_hs_dir() 108
+problem function-size /src/feature/rend/rendservice.c:upload_service_descriptor() 111
+problem function-size /src/feature/rend/rendservice.c:rend_consider_services_intro_points() 170
+problem function-size /src/feature/stats/rephist.c:rep_hist_load_mtbf_data() 185
+problem function-size /src/feature/stats/rephist.c:rep_hist_format_exit_stats() 148
+problem function-size /src/lib/compress/compress.c:tor_compress_impl() 133
+problem function-size /src/lib/compress/compress_zstd.c:tor_zstd_compress_process() 126
+problem function-size /src/lib/container/smartlist.c:smartlist_bsearch_idx() 109
+problem function-size /src/lib/crypt_ops/crypto_rand.c:crypto_strongest_rand_syscall() 102
+problem function-size /src/lib/encoding/binascii.c:base64_encode() 107
+problem function-size /src/lib/encoding/confline.c:parse_config_line_from_str_verbose() 119
+problem function-size /src/lib/encoding/cstring.c:unescape_string() 108
+problem function-size /src/lib/fs/dir.c:check_private_dir() 231
+problem function-size /src/lib/log/log.c:parse_log_severity_config() 101
+problem function-size /src/lib/math/prob_distr.c:sample_uniform_interval() 145
+problem function-size /src/lib/net/address.c:tor_addr_parse_mask_ports() 198
+problem function-size /src/lib/net/address.c:tor_addr_compare_masked() 111
+problem function-size /src/lib/net/inaddr.c:tor_inet_pton() 107
+problem function-size /src/lib/net/resolve.c:tor_addr_lookup() 110
+problem function-size /src/lib/net/socketpair.c:tor_ersatz_socketpair() 102
+problem function-size /src/lib/osinfo/uname.c:get_uname() 116
+problem function-size /src/lib/process/process_unix.c:process_unix_exec() 220
+problem function-size /src/lib/process/process_win32.c:process_win32_exec() 133
+problem function-size /src/lib/process/process_win32.c:process_win32_create_pipe() 112
+problem function-size /src/lib/process/restrict.c:set_max_file_descriptors() 102
+problem function-size /src/lib/process/setuid.c:switch_id() 156
+problem function-size /src/lib/sandbox/sandbox.c:prot_strings() 104
+problem function-size /src/lib/string/scanf.c:tor_vsscanf() 112
+problem function-size /src/lib/tls/tortls_nss.c:tor_tls_context_new() 153
+problem function-size /src/lib/tls/tortls_openssl.c:tor_tls_context_new() 171
+problem function-size /src/lib/tls/x509_nss.c:tor_tls_create_certificate_internal() 126
+problem function-size /src/tools/tor-gencert.c:parse_commandline() 111
+problem function-size /src/tools/tor-resolve.c:build_socks5_resolve_request() 104
+problem function-size /src/tools/tor-resolve.c:do_resolve() 174
+problem function-size /src/tools/tor-resolve.c:main() 112
+
diff --git a/scripts/maint/practracker/metrics.py b/scripts/maint/practracker/metrics.py
new file mode 100644
index 000000000..5fa305a86
--- /dev/null
+++ b/scripts/maint/practracker/metrics.py
@@ -0,0 +1,50 @@
+#!/usr/bin/python
+
+# Implementation of various source code metrics.
+# These are currently ad-hoc string operations and regexps.
+# We might want to use a proper static analysis library in the future, if we want to get more advanced metrics.
+
+import re
+
+def get_file_len(f):
+    """Get file length of file"""
+    for i, l in enumerate(f):
+        pass
+    return i + 1
+
+def get_include_count(f):
+    """Get number of #include statements in the file"""
+    include_count = 0
+    for line in f:
+        if re.match(r' *# *include', line):
+            include_count += 1
+    return include_count
+
+def get_function_lines(f):
+    """
+    Return iterator which iterates over functions and returns (function name, function lines)
+    """
+
+    # Skip lines that look like they are defining functions with these
+    # names: they aren't real function definitions.
+    REGEXP_CONFUSE_TERMS = {"MOCK_IMPL", "ENABLE_GCC_WARNINGS", "ENABLE_GCC_WARNING", "DUMMY_TYPECHECK_INSTANCE",
+                            "DISABLE_GCC_WARNING", "DISABLE_GCC_WARNINGS"}
+
+    in_function = False
+    for lineno, line in enumerate(f):
+        if not in_function:
+            # find the start of a function
+            m = re.match(r'^([a-zA-Z_][a-zA-Z_0-9]*),?\(', line)
+            if m:
+                func_name = m.group(1)
+                if func_name in REGEXP_CONFUSE_TERMS:
+                    continue
+                func_start = lineno
+                in_function = True
+
+        else:
+            # Find the end of a function
+            if line.startswith("}"):
+                n_lines = lineno - func_start
+                in_function = False
+                yield (func_name, n_lines)
diff --git a/scripts/maint/practracker/practracker.py b/scripts/maint/practracker/practracker.py
new file mode 100755
index 000000000..febb14639
--- /dev/null
+++ b/scripts/maint/practracker/practracker.py
@@ -0,0 +1,216 @@
+#!/usr/bin/python
+
+"""
+Best-practices tracker for Tor source code.
+
+Go through the various .c files and collect metrics about them. If the metrics
+violate some of our best practices and they are not found in the optional
+exceptions file, then log a problem about them.
+
+We currently do metrics about file size, function size and number of includes.
+
+practracker.py should be run with its second argument pointing to the Tor
+top-level source directory like this:
+  $ python3 ./scripts/maint/practracker/practracker.py .
+
+To regenerate the exceptions file so that it allows all current
+problems in the Tor source, use the --regen flag:
+  $ python3 --regen ./scripts/maint/practracker/practracker.py .
+"""
+
+from __future__ import print_function
+
+import os, sys
+
+import metrics
+import util
+import problem
+
+# The filename of the exceptions file (it should be placed in the practracker directory)
+EXCEPTIONS_FNAME = "./exceptions.txt"
+
+# Recommended file size
+MAX_FILE_SIZE = 3000 # lines
+# Recommended function size
+MAX_FUNCTION_SIZE = 100 # lines
+# Recommended number of #includes
+MAX_INCLUDE_COUNT = 50
+
+#######################################################
+
+# ProblemVault singleton
+ProblemVault = None
+
+# The Tor source code topdir
+TOR_TOPDIR = None
+
+#######################################################
+
+if sys.version_info[0] <= 2:
+    def open_file(fname):
+        return open(fname, 'r')
+else:
+    def open_file(fname):
+        return open(fname, 'r', encoding='utf-8')
+
+def consider_file_size(fname, f):
+    """Consider file size issues for 'f' and return True if a new issue was found"""
+    file_size = metrics.get_file_len(f)
+    if file_size > MAX_FILE_SIZE:
+        p = problem.FileSizeProblem(fname, file_size)
+        return ProblemVault.register_problem(p)
+    return False
+
+def consider_includes(fname, f):
+    """Consider #include issues for 'f' and return True if a new issue was found"""
+    include_count = metrics.get_include_count(f)
+
+    if include_count > MAX_INCLUDE_COUNT:
+        p = problem.IncludeCountProblem(fname, include_count)
+        return ProblemVault.register_problem(p)
+    return False
+
+def consider_function_size(fname, f):
+    """Consider the function sizes for 'f' and return True if a new issue was found"""
+    found_new_issues = False
+
+    for name, lines in metrics.get_function_lines(f):
+        # Don't worry about functions within our limits
+        if lines <= MAX_FUNCTION_SIZE:
+            continue
+
+        # That's a big function! Issue a problem!
+        canonical_function_name = "%s:%s()" % (fname, name)
+        p = problem.FunctionSizeProblem(canonical_function_name, lines)
+        found_new_issues |= ProblemVault.register_problem(p)
+
+    return found_new_issues
+
+#######################################################
+
+def consider_all_metrics(files_list):
+    """Consider metrics for all files, and return True if new issues were found"""
+    found_new_issues = False
+    for fname in files_list:
+        with open_file(fname) as f:
+            found_new_issues |= consider_metrics_for_file(fname, f)
+    return found_new_issues
+
+def consider_metrics_for_file(fname, f):
+    """
+    Consider the various metrics for file with filename 'fname' and file descriptor 'f'.
+    Return True if we found new issues.
+    """
+    # Strip the useless part of the path
+    if fname.startswith(TOR_TOPDIR):
+        fname = fname[len(TOR_TOPDIR):]
+
+    found_new_issues = False
+
+    # Get file length
+    found_new_issues |= consider_file_size(fname, f)
+
+    # Consider number of #includes
+    f.seek(0)
+    found_new_issues |= consider_includes(fname, f)
+
+    # Get function length
+    f.seek(0)
+    found_new_issues |= consider_function_size(fname, f)
+
+    return found_new_issues
+
+HEADER="""\
+# Welcome to the exceptions file for Tor's best-practices tracker!
+#
+# Each line of this file represents a single violation of Tor's best
+# practices -- typically, a violation that we had before practracker.py
+# first existed.
+#
+# There are three kinds of problems that we recognize right now:
+#   function-size -- a function of more than {MAX_FUNCTION_SIZE} lines.
+#   file-size -- a file of more than {MAX_FILE_SIZE} lines.
+#   include-count -- a file with more than {MAX_INCLUDE_COUNT} #includes.
+#
+# Each line below represents a single exception that practracker should
+# _ignore_. Each line has four parts:
+#  1. The word "problem".
+#  2. The kind of problem.
+#  3. The location of the problem: either a filename, or a
+#     filename:functionname pair.
+#  4. The magnitude of the problem to ignore.
+#
+# So for example, consider this line:
+#    problem file-size /src/core/or/connection_or.c 3200
+#
+# It tells practracker to allow the mentioned file to be up to 3200 lines
+# long, even though ordinarily it would warn about any file with more than
+# {MAX_FILE_SIZE} lines.
+#
+# You can either edit this file by hand, or regenerate it completely by
+# running `make practracker-regen`.
+#
+# Remember: It is better to fix the problem than to add a new exception!
+
+""".format(**globals())
+
+def main(argv):
+    import argparse
+
+    progname = argv[0]
+    parser = argparse.ArgumentParser(prog=progname)
+    parser.add_argument("--regen", action="store_true",
+                        help="Regenerate the exceptions file")
+    parser.add_argument("--exceptions",
+                        help="Override the location for the exceptions file")
+    parser.add_argument("topdir", default=".", nargs="?",
+                        help="Top-level directory for the tor source")
+    args = parser.parse_args(argv[1:])
+
+    global TOR_TOPDIR
+    TOR_TOPDIR = args.topdir
+    if args.exceptions:
+        exceptions_file = args.exceptions
+    else:
+        exceptions_file = os.path.join(TOR_TOPDIR, "scripts/maint/practracker", EXCEPTIONS_FNAME)
+
+    # 1) Get all the .c files we care about
+    files_list = util.get_tor_c_files(TOR_TOPDIR)
+
+    # 2) Initialize problem vault and load an optional exceptions file so that
+    # we don't warn about the past
+    global ProblemVault
+
+    if args.regen:
+        tmpname = exceptions_file + ".tmp"
+        tmpfile = open(tmpname, "w")
+        sys.stdout = tmpfile
+        sys.stdout.write(HEADER)
+        ProblemVault = problem.ProblemVault()
+    else:
+        ProblemVault = problem.ProblemVault(exceptions_file)
+
+    # 3) Go through all the files and report problems if they are not exceptions
+    found_new_issues = consider_all_metrics(files_list)
+
+    if args.regen:
+        tmpfile.close()
+        os.rename(tmpname, exceptions_file)
+        sys.exit(0)
+
+    # If new issues were found, try to give out some advice to the developer on how to resolve it.
+    if found_new_issues and not args.regen:
+        new_issues_str = """\
+FAILURE: practracker found new problems in the code: see warnings above.
+
+Please fix the problems if you can, and update the exceptions file
+({}) if you can't.
+
+See doc/HACKING/HelpfulTools.md for more information on using practracker.\
+""".format(exceptions_file)
+        print(new_issues_str)
+
+    sys.exit(found_new_issues)
+
+if __name__ == '__main__':
+    main(sys.argv)
diff --git a/scripts/maint/practracker/practracker_tests.py b/scripts/maint/practracker/practracker_tests.py
new file mode 100755
index 000000000..cdbab2908
--- /dev/null
+++ b/scripts/maint/practracker/practracker_tests.py
@@ -0,0 +1,50 @@
+"""Some simple tests for practracker metrics"""
+
+import unittest
+
+import StringIO
+
+import metrics
+
+function_file = """static void
+fun(directory_request_t *req, const char *resource)
+{
+  time_t if_modified_since = 0;
+  uint8_t or_diff_from[DIGEST256_LEN];
+}
+
+static void
+fun(directory_request_t *req,
+      const char *resource)
+{
+  time_t if_modified_since = 0;
+  uint8_t or_diff_from[DIGEST256_LEN];
+}
+
+MOCK_IMPL(void,
+fun,(
+       uint8_t dir_purpose,
+       uint8_t router_purpose,
+       const char *resource,
+       int pds_flags,
+       download_want_authority_t want_authority))
+{
+  const routerstatus_t *rs = NULL;
+  const or_options_t *options = get_options();
+}
+"""
+
+class TestFunctionLength(unittest.TestCase):
+    def test_function_length(self):
+        funcs = StringIO.StringIO(function_file)
+        # All functions should have length 2
+        for name, lines in metrics.function_lines(funcs):
+            self.assertEqual(name, "fun")
+
+        funcs.seek(0)
+
+        for name, lines in metrics.function_lines(funcs):
+            self.assertEqual(lines, 2)
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/scripts/maint/practracker/problem.py b/scripts/maint/practracker/problem.py
new file mode 100644
index 000000000..c82c5db57
--- /dev/null
+++ b/scripts/maint/practracker/problem.py
@@ -0,0 +1,158 @@
+"""
+In this file we define a ProblemVault class where we store all the
+exceptions and all the problems we find with the code.
+
+The ProblemVault is capable of registering problems and also figuring out if a
+problem is worse than a registered exception so that it only warns when things
+get worse.
+"""
+
+from __future__ import print_function
+
+import os.path
+import re
+import sys
+
+class ProblemVault(object):
+    """
+    Singleton where we store the various new problems we
+    found in the code, and also the old problems we read from the exception
+    file.
+    """
+    def __init__(self, exception_fname=None):
+        # Exception dictionary: { problem.key() : Problem object }
+        self.exceptions = {}
+
+        if exception_fname == None:
+            return
+
+        try:
+            with open(exception_fname, 'r') as exception_f:
+                self.register_exceptions(exception_f)
+        except IOError:
+            print("No exception file provided", file=sys.stderr)
+
+    def register_exceptions(self, exception_file):
+        # Register exceptions
+        for lineno, line in enumerate(exception_file, 1):
+            try:
+                problem = get_old_problem_from_exception_str(line)
+            except ValueError as v:
+                print("Exception file line {} not recognized: {}"
+                      .format(lineno,v),
+                      file=sys.stderr)
+                continue
+
+            if problem is None:
+                continue
+
+            # Fail if we see dup exceptions. There is really no reason to have dup exceptions.
+            if problem.key() in self.exceptions:
+                print("Duplicate exceptions lines found in exception file:\n\t{}\n\t{}\nAborting...".format(problem, self.exceptions[problem.key()]),
+                      file=sys.stderr)
+                sys.exit(1)
+
+            self.exceptions[problem.key()] = problem
+            #print "Registering exception: %s" % problem
+
+    def register_problem(self, problem):
+        """
+        Register this problem to the problem value. Return True if it was a new
+        problem or it worsens an already existing problem.
+        """
+        # This is a new problem, print it
+        if problem.key() not in self.exceptions:
+            print(problem)
+            return True
+
+        # If it's an old problem, we don't warn if the situation got better
+        # (e.g. we went from 4k LoC to 3k LoC), but we do warn if the
+        # situation worsened (e.g. we went from 60 includes to 80).
+        if problem.is_worse_than(self.exceptions[problem.key()]):
+            print(problem)
+            return True
+
+        return False
+
+class Problem(object):
+    """
+    A generic problem in our source code. See the subclasses below for the
+    specific problems we are trying to tackle.
+    """
+    def __init__(self, problem_type, problem_location, metric_value):
+        self.problem_location = problem_location
+        self.metric_value = int(metric_value)
+        self.problem_type = problem_type
+
+    def is_worse_than(self, other_problem):
+        """Return True if this is a worse problem than other_problem"""
+        if self.metric_value > other_problem.metric_value:
+            return True
+        return False
+
+    def key(self):
+        """Generate a unique key that describes this problem that can be used as a dictionary key"""
+        # Problem location is a filesystem path, so we need to normalize this
+        # across platforms otherwise same paths are not gonna match.
+        canonical_location = os.path.normcase(self.problem_location)
+        return "%s:%s" % (canonical_location, self.problem_type)
+
+    def __str__(self):
+        return "problem %s %s %s" % (self.problem_type, self.problem_location, self.metric_value)
+
+class FileSizeProblem(Problem):
+    """
+    Denotes a problem with the size of a .c file.
+
+    The 'problem_location' is the filesystem path of the .c file, and the
+    'metric_value' is the number of lines in the .c file.
+    """
+    def __init__(self, problem_location, metric_value):
+        super(FileSizeProblem, self).__init__("file-size", problem_location, metric_value)
+
+class IncludeCountProblem(Problem):
+    """
+    Denotes a problem with the number of #includes in a .c file.
+
+    The 'problem_location' is the filesystem path of the .c file, and the
+    'metric_value' is the number of #includes in the .c file.
+    """
+    def __init__(self, problem_location, metric_value):
+        super(IncludeCountProblem, self).__init__("include-count", problem_location, metric_value)
+
+class FunctionSizeProblem(Problem):
+    """
+    Denotes a problem with a size of a function in a .c file.
+
+    The 'problem_location' is "<path>:<function>()" where <path> is the
+    filesystem path of the .c file and <function> is the name of the offending
+    function.
+
+    The 'metric_value' is the size of the offending function in lines.
+    """
+    def __init__(self, problem_location, metric_value):
+        super(FunctionSizeProblem, self).__init__("function-size", problem_location, metric_value)
+
+comment_re = re.compile(r'#.*$')
+
+def get_old_problem_from_exception_str(exception_str):
+    orig_str = exception_str
+    exception_str = comment_re.sub("", exception_str)
+    fields = exception_str.split()
+    if len(fields) == 0:
+        # empty line or comment
+        return None
+    elif len(fields) == 4:
+        # valid line
+        _, problem_type, problem_location, metric_value = fields
+    else:
+        raise ValueError("Misformatted line {!r}".format(orig_str))
+
+    if problem_type == "file-size":
+        return FileSizeProblem(problem_location, metric_value)
+    elif problem_type == "include-count":
+        return IncludeCountProblem(problem_location, metric_value)
+    elif problem_type == "function-size":
+        return FunctionSizeProblem(problem_location, metric_value)
+    else:
+        raise ValueError("Unknown exception type {!r}".format(orig_str))
diff --git a/scripts/maint/practracker/util.py b/scripts/maint/practracker/util.py
new file mode 100644
index 000000000..b0ca73b99
--- /dev/null
+++ b/scripts/maint/practracker/util.py
@@ -0,0 +1,28 @@
+import os
+
+# We don't want to run metrics for unittests, automatically-generated C files,
+# external libraries or git leftovers.
+EXCLUDE_SOURCE_DIRS = {"/src/test/", "/src/trunnel/", "/src/ext/", "/.git/"}
+
+def get_tor_c_files(tor_topdir):
+    """
+    Return a list with the .c filenames we want to get metrics of.
+    """
+    files_list = []
+
+    for root, directories, filenames in os.walk(tor_topdir):
+        directories.sort()
+        filenames.sort()
+        for filename in filenames:
+            # We only care about .c files
+            if not filename.endswith(".c"):
+                continue
+
+            # Exclude the excluded paths
+            full_path = os.path.join(root,filename)
+            if any(os.path.normcase(exclude_dir) in full_path for exclude_dir in EXCLUDE_SOURCE_DIRS):
+                continue
+
+            files_list.append(full_path)
+
+    return files_list
diff --git a/scripts/maint/pre-commit.git-hook b/scripts/maint/pre-commit.git-hook
deleted file mode 100755
index b4c4ce206..000000000
--- a/scripts/maint/pre-commit.git-hook
+++ /dev/null
@@ -1,26 +0,0 @@
-#!/bin/bash
-#
-# To install this script, copy it to .git/hooks/pre-commit in local copy of
-# tor git repo and make sure it has permission to execute.
-#
-# This is pre-commit git hook script that prevents commiting your changeset if
-# it fails our code formatting or changelog entry formatting checkers.
-
-workdir=$(git rev-parse --show-toplevel)
-
-cd "$workdir" || exit 1
-
-python scripts/maint/lintChanges.py ./changes/*
-
-perl scripts/maint/checkSpace.pl -C \
-src/lib/*/*.[ch] \
-src/core/*/*.[ch] \
-src/feature/*/*.[ch] \
-src/app/*/*.[ch] \
-src/test/*.[ch] \
-src/test/*/*.[ch] \
-src/tools/*.[ch]
-
-if test -e scripts/maint/checkIncludes.py; then
-    python scripts/maint/checkIncludes.py
-fi
diff --git a/scripts/maint/pre-push.git-hook b/scripts/maint/pre-push.git-hook
deleted file mode 100755
index 26296023f..000000000
--- a/scripts/maint/pre-push.git-hook
+++ /dev/null
@@ -1,61 +0,0 @@
-#!/bin/bash
-
-# To install this script, copy it into .git/hooks/pre-push path in your
-# local copy of git repository. Make sure it has permission to execute.
-#
-# This is git pre-push hook script to prevent "fixup!" and "squash!" commits
-# from ending up in upstream branches (master, release-* or maint-*).
-#
-# The following sample script was used as starting point:
-# https://github.com/git/git/blob/master/templates/hooks--pre-push.sample
-
-z40=0000000000000000000000000000000000000000
-
-CUR_BRANCH=$(git rev-parse --abbrev-ref HEAD)
-if [ "$CUR_BRANCH" != "master" ] && [[ $CUR_BRANCH != release-* ]] &&
-        [[ $CUR_BRANCH != maint-* ]]
-then
-        exit 0
-fi
-
-echo "Running pre-push hook"
-
-# shellcheck disable=SC2034
-while read -r local_ref local_sha remote_ref remote_sha
-do
-	if [ "$local_sha" = $z40 ]
-	then
-		# Handle delete
-		:
-	else
-		if [ "$remote_sha" = $z40 ]
-		then
-			# New branch, examine all commits
-			range="$local_sha"
-		else
-			# Update to existing branch, examine new commits
-			range="$remote_sha..$local_sha"
-		fi
-
-                # Check for fixup! commit
-                commit=$(git rev-list -n 1 --grep '^fixup!' "$range")
-		if [ -n "$commit" ]
-		then
-			echo >&2 "Found fixup! commit in $local_ref, not pushing"
-			echo >&2 "If you really want to push this, use --no-verify."
-			exit 1
-		fi
-
-                # Check for squash! commit
-                commit=$(git rev-list -n 1 --grep '^squash!' "$range")
-		if [ -n "$commit" ]
-		then
-			echo >&2 "Found squash! commit in $local_ref, not pushing"
-			echo >&2 "If you really want to push this, use --no-verify."
-			exit 1
-		fi
-	fi
-done
-
-exit 0
-
diff --git a/scripts/maint/rectify_include_paths.py b/scripts/maint/rectify_include_paths.py
index 401fadae6..1140e8cd2 100755
--- a/scripts/maint/rectify_include_paths.py
+++ b/scripts/maint/rectify_include_paths.py
@@ -1,8 +1,12 @@
-#!/usr/bin/python3
+#!/usr/bin/python
 
 import os
 import os.path
 import re
+import sys
+
+def warn(msg):
+    sys.stderr.write("WARNING: %s\n"%msg)
 
 # Find all the include files, map them to their real names.
 
@@ -11,6 +15,8 @@ def exclude(paths, dirnames):
         if p in dirnames:
             dirnames.remove(p)
 
+DUPLICATE = object()
+
 def get_include_map():
     includes = { }
 
@@ -19,7 +25,10 @@ def get_include_map():
 
         for fname in fnames:
             if fname.endswith(".h"):
-                assert fname not in includes
+                if fname in includes:
+                    warn("Multiple headers named %s"%fname)
+                    includes[fname] = DUPLICATE
+                    continue
                 include = os.path.join(dirpath, fname)
                 assert include.startswith("src/")
                 includes[fname] = include[4:]
@@ -37,7 +46,7 @@ def fix_includes(inp, out, mapping):
         if m:
             include,hdr,rest = m.groups()
             basehdr = get_base_header_name(hdr)
-            if basehdr in mapping:
+            if basehdr in mapping and mapping[basehdr] is not DUPLICATE:
                 out.write('{}{}{}\n'.format(include,mapping[basehdr],rest))
                 continue
 
diff --git a/scripts/maint/updateCopyright.pl b/scripts/maint/updateCopyright.pl
index 36894b1ba..6800032f8 100755
--- a/scripts/maint/updateCopyright.pl
+++ b/scripts/maint/updateCopyright.pl
@@ -1,7 +1,9 @@
 #!/usr/bin/perl -i -w -p
 
-$NEWYEAR=2019;
+@now = gmtime();
 
-s/Copyright(.*) (201[^9]), The Tor Project/Copyright$1 $2-${NEWYEAR}, The Tor Project/;
+$NEWYEAR=$now[5]+1900;
+
+s/Copyright([^-]*) (20[^-]*), The Tor Project/Copyright$1 $2-${NEWYEAR}, The Tor Project/;
 
 s/Copyright(.*)-(20..), The Tor Project/Copyright$1-${NEWYEAR}, The Tor Project/;
diff --git a/scripts/test/cov-diff b/scripts/test/cov-diff
index f3ca85688..875180096 100755
--- a/scripts/test/cov-diff
+++ b/scripts/test/cov-diff
@@ -16,6 +16,5 @@ for B in "$DIRB"/*; do
   fi
   perl -pe 's/^\s*\!*\d+(\*?):/        1$1:/; s/^([^:]+:)[\d\s]+:/$1/; s/^ *-:(Runs|Programs):.*//;' "$B" > "$B.tmp"
   diff -u "$A.tmp" "$B.tmp" |perl -pe 's/^((?:\+\+\+|---)(?:.*tmp))\s+.*/$1/;'
-  rm "$A.tmp" "$B.tmp"
+  rm -f "$A.tmp" "$B.tmp"
 done
-
diff --git a/scripts/test/cov-test-determinism.sh b/scripts/test/cov-test-determinism.sh
new file mode 100755
index 000000000..3458f9696
--- /dev/null
+++ b/scripts/test/cov-test-determinism.sh
@@ -0,0 +1,51 @@
+#!/bin/sh
+
+# To use this script, build Tor with coverage enabled, and then say:
+#  ./scripts/test/cov-test-determinism.sh run
+#
+# Let it run for a long time so it can run the tests over and over.  It
+# will put their coverage outputs in coverage-raw/coverage-*/.
+#
+# Then say:
+#  ./scripts/test/cov-test-determinism.sh check
+#
+# It will diff the other coverage outputs to the first one, and put their
+# diffs in coverage-raw/diff-coverage-*.
+
+run=0
+check=0
+
+if test "$1" = run; then
+    run=1
+elif test "$1" = check; then
+    check=1
+else
+    echo "First use 'run' with this script, then use 'check'."
+    exit 1
+fi
+
+if test "$run" = 1; then
+    # same seed as in travis.yml
+    TOR_TEST_RNG_SEED="636f766572616765"
+    export TOR_TEST_RNG_SEED
+    while true; do
+        make reset-gcov
+        CD=coverage-raw/coverage-$(date +%s)
+        make -j5 check
+        mkdir -p "$CD"
+        ./scripts/test/coverage "$CD"
+    done
+fi
+
+if test "$check" = 1; then
+    cd coverage-raw || exit 1
+
+    FIRST="$(find . -name "coverage-*" -type d | head -1)"
+    rm -f A
+    ln -sf "$FIRST" A
+    for dir in coverage-*; do
+        rm -f B
+        ln -sf "$dir" B
+        ../scripts/test/cov-diff A B > "diff-$dir"
+    done
+fi
diff --git a/src/app/config/auth_dirs.inc b/src/app/config/auth_dirs.inc
index 08a919b05..278f08bfc 100644
--- a/src/app/config/auth_dirs.inc
+++ b/src/app/config/auth_dirs.inc
@@ -7,7 +7,7 @@
   "86.59.21.38:80 847B 1F85 0344 D787 6491 A548 92F9 0493 4E4E B85D",
 "dizum orport=443 "
   "v3ident=E8A9C45EDE6D711294FADF8E7951F4DE6CA56B58 "
-  "194.109.206.212:80 7EA6 EAD6 FD83 083C 538F 4403 8BBF A077 587D D755",
+  "45.66.33.45:80 7EA6 EAD6 FD83 083C 538F 4403 8BBF A077 587D D755",
 "Serge orport=9001 bridge "
   "66.111.2.131:9030 BA44 A889 E64B 93FA A2B1 14E0 2C2A 279A 8555 C533",
 "gabelmoo orport=443 "
diff --git a/src/app/config/config.c b/src/app/config/config.c
index 0d5cc3395..a06187174 100644
--- a/src/app/config/config.c
+++ b/src/app/config/config.c
@@ -86,6 +86,8 @@
 #include "feature/client/entrynodes.h"
 #include "feature/client/transports.h"
 #include "feature/control/control.h"
+#include "feature/control/control_auth.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/bwauth.h"
 #include "feature/dirauth/guardfraction.h"
 #include "feature/dircache/consdiffmgr.h"
@@ -154,6 +156,7 @@
 #include "lib/evloop/procmon.h"
 
 #include "feature/dirauth/dirvote.h"
+#include "feature/dirauth/dirauth_periodic.h"
 #include "feature/dirauth/recommend_pkg.h"
 #include "feature/dirauth/authmode.h"
 
@@ -594,6 +597,8 @@ static config_var_t option_vars_[] = {
   V(ReducedConnectionPadding,    BOOL,     "0"),
   V(ConnectionPadding,           AUTOBOOL, "auto"),
   V(RefuseUnknownExits,          AUTOBOOL, "auto"),
+  V(CircuitPadding,              BOOL,     "1"),
+  V(ReducedCircuitPadding,       BOOL,     "0"),
   V(RejectPlaintextPorts,        CSV,      ""),
   V(RelayBandwidthBurst,         MEMUNIT,  "0"),
   V(RelayBandwidthRate,          MEMUNIT,  "0"),
@@ -2382,7 +2387,8 @@ options_act(const or_options_t *old_options)
     if (!bool_eq(directory_fetches_dir_info_early(options),
                  directory_fetches_dir_info_early(old_options)) ||
         !bool_eq(directory_fetches_dir_info_later(options),
-                 directory_fetches_dir_info_later(old_options))) {
+                 directory_fetches_dir_info_later(old_options)) ||
+        !config_lines_eq(old_options->Bridges, options->Bridges)) {
       /* Make sure update_router_have_minimum_dir_info() gets called. */
       router_dir_info_changed();
       /* We might need to download a new consensus status later or sooner than
@@ -3545,7 +3551,7 @@ options_validate(or_options_t *old_options, or_options_t *options,
     tor_free(t);
     t = format_recommended_version_list(options->RecommendedServerVersions, 1);
     tor_free(t);
-#endif
+#endif /* defined(HAVE_MODULE_DIRAUTH) */
 
     if (options->UseEntryGuards) {
       log_info(LD_CONFIG, "Authoritative directory servers can't set "
@@ -3561,6 +3567,7 @@ options_validate(or_options_t *old_options, or_options_t *options,
           options->V3AuthoritativeDir))
       REJECT("AuthoritativeDir is set, but none of "
              "(Bridge/V3)AuthoritativeDir is set.");
+#ifdef HAVE_MODULE_DIRAUTH
     /* If we have a v3bandwidthsfile and it's broken, complain on startup */
     if (options->V3BandwidthsFile && !old_options) {
       dirserv_read_measured_bandwidths(options->V3BandwidthsFile, NULL, NULL,
@@ -3570,6 +3577,7 @@ options_validate(or_options_t *old_options, or_options_t *options,
     if (options->GuardfractionFile && !old_options) {
       dirserv_read_guardfraction_file(options->GuardfractionFile, NULL);
     }
+#endif /* defined(HAVE_MODULE_DIRAUTH) */
   }
 
   if (options->AuthoritativeDir && !options->DirPort_set)
@@ -3747,6 +3755,14 @@ options_validate(or_options_t *old_options, or_options_t *options,
     REJECT("Relays cannot set ReducedConnectionPadding. ");
   }
 
+  if (server_mode(options) && options->CircuitPadding == 0) {
+    REJECT("Relays cannot set CircuitPadding to 0. ");
+  }
+
+  if (server_mode(options) && options->ReducedCircuitPadding == 1) {
+    REJECT("Relays cannot set ReducedCircuitPadding. ");
+  }
+
   if (options->BridgeDistribution) {
     if (!options->BridgeRelay) {
       REJECT("You set BridgeDistribution, but you didn't set BridgeRelay!");
@@ -4197,6 +4213,10 @@ options_validate(or_options_t *old_options, or_options_t *options,
              "You should also make sure you aren't listing this bridge's "
              "fingerprint in any other MyFamily.");
   }
+  if (options->MyFamily_lines && !options->ContactInfo) {
+    log_warn(LD_CONFIG, "MyFamily is set but ContactInfo is not configured. "
+             "ContactInfo should always be set when MyFamily option is too.");
+  }
   if (normalize_nickname_list(&options->MyFamily,
                               options->MyFamily_lines, "MyFamily", msg))
     return -1;
@@ -4585,7 +4605,7 @@ compute_real_max_mem_in_queues(const uint64_t val, int log_guess)
 #else
 /* On a 32-bit platform, we can't have 8GB of ram. */
 #define RAM_IS_VERY_LARGE(x) (0)
-#endif
+#endif /* SIZEOF_SIZE_T > 4 */
 
       if (RAM_IS_VERY_LARGE(ram)) {
         /* If we have 8 GB, or more, RAM available, we set the MaxMemInQueues
@@ -5757,7 +5777,7 @@ options_init_logs(const or_options_t *old_options, or_options_t *options,
 #else
         log_warn(LD_CONFIG, "Android logging is not supported"
                             " on this system. Sorry.");
-#endif // HAVE_ANDROID_LOG_H.
+#endif /* defined(HAVE_ANDROID_LOG_H) */
         goto cleanup;
       }
     }
@@ -7071,7 +7091,7 @@ parse_port_config(smartlist_t *out,
         if (!strcasecmpstart(elt, "SessionGroup=")) {
           int group = (int)tor_parse_long(elt+strlen("SessionGroup="),
                                           10, 0, INT_MAX, &ok, NULL);
-          if (!ok || !allow_no_stream_options) {
+          if (!ok || allow_no_stream_options) {
             log_warn(LD_CONFIG, "Invalid %sPort option '%s'",
                      portname, escaped(elt));
             goto err;
diff --git a/src/app/config/confparse.c b/src/app/config/confparse.c
index 8681f648d..729e7a447 100644
--- a/src/app/config/confparse.c
+++ b/src/app/config/confparse.c
@@ -225,6 +225,7 @@ config_assign_value(const config_format_t *fmt, void *options,
       tor_asprintf(msg,
           "Interval '%s %s' is malformed or out of bounds.",
           c->key, c->value);
+      tor_free(tmp);
       return -1;
     }
     *(int *)lvalue = i;
diff --git a/src/app/config/or_options_st.h b/src/app/config/or_options_st.h
index bd707fd19..2ee2d1567 100644
--- a/src/app/config/or_options_st.h
+++ b/src/app/config/or_options_st.h
@@ -248,6 +248,17 @@ struct or_options_t {
    * pad to the server regardless of server support. */
   int ConnectionPadding;
 
+  /** Boolean: if true, then circuit padding will be negotiated by client
+   * and server, subject to consenus limits (default). If 0, it will be fully
+   * disabled. */
+  int CircuitPadding;
+
+  /** Boolean: if true, then this client will only use circuit padding
+   * algorithms that are known to use a low amount of overhead. If false,
+   * we will use all available circuit padding algorithms.
+   */
+  int ReducedCircuitPadding;
+
   /** To what authority types do we publish our descriptor? Choices are
    * "v1", "v2", "v3", "bridge", or "". */
   struct smartlist_t *PublishServerDescriptor;
@@ -1099,4 +1110,4 @@ struct or_options_t {
   int DormantCanceledByStartup;
 };
 
-#endif
+#endif /* !defined(TOR_OR_OPTIONS_ST_H) */
diff --git a/src/app/config/or_state_st.h b/src/app/config/or_state_st.h
index cdb9b3828..f45c6196c 100644
--- a/src/app/config/or_state_st.h
+++ b/src/app/config/or_state_st.h
@@ -96,4 +96,4 @@ struct or_state_t {
   int Dormant;
 };
 
-#endif
+#endif /* !defined(TOR_OR_STATE_ST_H) */
diff --git a/src/app/config/statefile.c b/src/app/config/statefile.c
index 9681f6f8b..fdfd68b24 100644
--- a/src/app/config/statefile.c
+++ b/src/app/config/statefile.c
@@ -36,7 +36,7 @@
 #include "core/mainloop/mainloop.h"
 #include "core/mainloop/netstatus.h"
 #include "core/mainloop/connection.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/client/entrynodes.h"
 #include "feature/hibernate/hibernate.h"
 #include "feature/stats/rephist.h"
diff --git a/src/app/config/statefile.h b/src/app/config/statefile.h
index 195007845..515c90a52 100644
--- a/src/app/config/statefile.h
+++ b/src/app/config/statefile.h
@@ -31,6 +31,6 @@ STATIC struct config_line_t *get_transport_in_state_by_name(
 STATIC void or_state_free_(or_state_t *state);
 #define or_state_free(st) FREE_AND_NULL(or_state_t, or_state_free_, (st))
 STATIC or_state_t *or_state_new(void);
-#endif
+#endif /* defined(STATEFILE_PRIVATE) */
 
 #endif /* !defined(TOR_STATEFILE_H) */
diff --git a/src/app/main/main.c b/src/app/main/main.c
index 4b60763f7..6e325f0b1 100644
--- a/src/app/main/main.c
+++ b/src/app/main/main.c
@@ -15,66 +15,51 @@
 #include "app/config/statefile.h"
 #include "app/main/main.h"
 #include "app/main/ntmain.h"
+#include "app/main/shutdown.h"
 #include "app/main/subsysmgr.h"
 #include "core/mainloop/connection.h"
 #include "core/mainloop/cpuworker.h"
 #include "core/mainloop/mainloop.h"
+#include "core/mainloop/mainloop_pubsub.h"
 #include "core/mainloop/netstatus.h"
 #include "core/or/channel.h"
 #include "core/or/channelpadding.h"
 #include "core/or/circuitpadding.h"
-#include "core/or/channeltls.h"
 #include "core/or/circuitlist.h"
-#include "core/or/circuitmux_ewma.h"
 #include "core/or/command.h"
-#include "core/or/connection_edge.h"
 #include "core/or/connection_or.h"
-#include "core/or/dos.h"
-#include "core/or/policies.h"
-#include "core/or/protover.h"
 #include "core/or/relay.h"
-#include "core/or/scheduler.h"
 #include "core/or/status.h"
-#include "core/or/versions.h"
 #include "feature/api/tor_api.h"
 #include "feature/api/tor_api_internal.h"
 #include "feature/client/addressmap.h"
-#include "feature/client/bridges.h"
-#include "feature/client/entrynodes.h"
-#include "feature/client/transports.h"
 #include "feature/control/control.h"
-#include "feature/dirauth/bwauth.h"
+#include "feature/control/control_auth.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/keypin.h"
 #include "feature/dirauth/process_descs.h"
 #include "feature/dircache/consdiffmgr.h"
-#include "feature/dircache/dirserv.h"
 #include "feature/dirparse/routerparse.h"
 #include "feature/hibernate/hibernate.h"
-#include "feature/hs/hs_cache.h"
 #include "feature/nodelist/authcert.h"
-#include "feature/nodelist/microdesc.h"
 #include "feature/nodelist/networkstatus.h"
-#include "feature/nodelist/nodelist.h"
 #include "feature/nodelist/routerlist.h"
 #include "feature/relay/dns.h"
 #include "feature/relay/ext_orport.h"
-#include "feature/relay/onion_queue.h"
 #include "feature/relay/routerkeys.h"
 #include "feature/relay/routermode.h"
 #include "feature/rend/rendcache.h"
-#include "feature/rend/rendclient.h"
 #include "feature/rend/rendservice.h"
-#include "feature/stats/geoip_stats.h"
 #include "feature/stats/predict_ports.h"
 #include "feature/stats/rephist.h"
 #include "lib/compress/compress.h"
 #include "lib/buf/buffers.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/crypt_ops/crypto_s2k.h"
-#include "lib/geoip/geoip.h"
 #include "lib/net/resolve.h"
 
 #include "lib/process/waitpid.h"
+#include "lib/pubsub/pubsub_build.h"
 
 #include "lib/meminfo/meminfo.h"
 #include "lib/osinfo/uname.h"
@@ -90,7 +75,6 @@
 
 #include <event2/event.h>
 
-#include "feature/dirauth/dirvote.h"
 #include "feature/dirauth/authmode.h"
 #include "feature/dirauth/shared_random.h"
 
@@ -111,8 +95,6 @@
 #include <systemd/sd-daemon.h>
 #endif /* defined(HAVE_SYSTEMD) */
 
-void evdns_shutdown(int);
-
 #ifdef HAVE_RUST
 // helper function defined in Rust to output a log message indicating if tor is
 // running with Rust enabled. See src/rust/tor_util
@@ -670,7 +652,7 @@ tor_init(int argc, char *argv[])
     log_err(LD_BUG, "Unable to initialize OpenSSL. Exiting.");
     return -1;
   }
-  stream_choice_seed_weak_rng();
+
   if (tor_init_libevent_rng() < 0) {
     log_warn(LD_NET, "Problem initializing libevent RNG.");
   }
@@ -743,86 +725,6 @@ release_lockfile(void)
   }
 }
 
-/** Free all memory that we might have allocated somewhere.
- * If <b>postfork</b>, we are a worker process and we want to free
- * only the parts of memory that we won't touch. If !<b>postfork</b>,
- * Tor is shutting down and we should free everything.
- *
- * Helps us find the real leaks with sanitizers and the like. Also valgrind
- * should then report 0 reachable in its leak report (in an ideal world --
- * in practice libevent, SSL, libc etc never quite free everything). */
-void
-tor_free_all(int postfork)
-{
-  if (!postfork) {
-    evdns_shutdown(1);
-  }
-  geoip_free_all();
-  geoip_stats_free_all();
-  dirvote_free_all();
-  routerlist_free_all();
-  networkstatus_free_all();
-  addressmap_free_all();
-  dirserv_free_fingerprint_list();
-  dirserv_free_all();
-  dirserv_clear_measured_bw_cache();
-  rend_cache_free_all();
-  rend_service_authorization_free_all();
-  rep_hist_free_all();
-  dns_free_all();
-  clear_pending_onions();
-  circuit_free_all();
-  circpad_machines_free();
-  entry_guards_free_all();
-  pt_free_all();
-  channel_tls_free_all();
-  channel_free_all();
-  connection_free_all();
-  connection_edge_free_all();
-  scheduler_free_all();
-  nodelist_free_all();
-  microdesc_free_all();
-  routerparse_free_all();
-  ext_orport_free_all();
-  control_free_all();
-  protover_free_all();
-  bridges_free_all();
-  consdiffmgr_free_all();
-  hs_free_all();
-  dos_free_all();
-  circuitmux_ewma_free_all();
-  accounting_free_all();
-  protover_summary_cache_free_all();
-
-  if (!postfork) {
-    config_free_all();
-    or_state_free_all();
-    router_free_all();
-    routerkeys_free_all();
-    policies_free_all();
-  }
-  if (!postfork) {
-#ifndef _WIN32
-    tor_getpwnam(NULL);
-#endif
-  }
-  /* stuff in main.c */
-
-  tor_mainloop_free_all();
-
-  if (!postfork) {
-    release_lockfile();
-  }
-  tor_libevent_free_all();
-
-  subsystems_shutdown();
-
-  /* Stuff in util.c and address.c*/
-  if (!postfork) {
-    esc_router_info(NULL);
-  }
-}
-
 /**
  * Remove the specified file, and log a warning if the operation fails for
  * any reason other than the file not existing. Ignores NULL filenames.
@@ -836,50 +738,6 @@ tor_remove_file(const char *filename)
   }
 }
 
-/** Do whatever cleanup is necessary before shutting Tor down. */
-void
-tor_cleanup(void)
-{
-  const or_options_t *options = get_options();
-  if (options->command == CMD_RUN_TOR) {
-    time_t now = time(NULL);
-    /* Remove our pid file. We don't care if there was an error when we
-     * unlink, nothing we could do about it anyways. */
-    tor_remove_file(options->PidFile);
-    /* Remove control port file */
-    tor_remove_file(options->ControlPortWriteToFile);
-    /* Remove cookie authentication file */
-    {
-      char *cookie_fname = get_controller_cookie_file_name();
-      tor_remove_file(cookie_fname);
-      tor_free(cookie_fname);
-    }
-    /* Remove Extended ORPort cookie authentication file */
-    {
-      char *cookie_fname = get_ext_or_auth_cookie_file_name();
-      tor_remove_file(cookie_fname);
-      tor_free(cookie_fname);
-    }
-    if (accounting_is_enabled(options))
-      accounting_record_bandwidth_usage(now, get_or_state());
-    or_state_mark_dirty(get_or_state(), 0); /* force an immediate save. */
-    or_state_save(now);
-    if (authdir_mode(options)) {
-      sr_save_and_cleanup();
-    }
-    if (authdir_mode_tests_reachability(options))
-      rep_hist_record_mtbf_data(now, 0);
-    keypin_close_journal();
-  }
-
-  timers_shutdown();
-
-  tor_free_all(0); /* We could move tor_free_all back into the ifdef below
-                      later, if it makes shutdown unacceptably slow.  But for
-                      now, leave it here: it's helped us catch bugs in the
-                      past. */
-}
-
 /** Read/create keys as needed, and echo our fingerprint to stdout. */
 static int
 do_list_fingerprint(void)
@@ -1377,6 +1235,30 @@ run_tor_main_loop(void)
   return do_main_loop();
 }
 
+/** Install the publish/subscribe relationships for all the subsystems. */
+static void
+pubsub_install(void)
+{
+    pubsub_builder_t *builder = pubsub_builder_new();
+    int r = subsystems_add_pubsub(builder);
+    tor_assert(r == 0);
+    r = tor_mainloop_connect_pubsub(builder); // consumes builder
+    tor_assert(r == 0);
+}
+
+/** Connect the mainloop to its publish/subscribe message delivery events if
+ * appropriate, and configure the global channels appropriately. */
+static void
+pubsub_connect(void)
+{
+  if (get_options()->command == CMD_RUN_TOR) {
+    tor_mainloop_connect_pubsub_events();
+    /* XXXX For each pubsub channel, its delivery strategy should be set at
+     * this XXXX point, using tor_mainloop_set_delivery_strategy().
+     */
+  }
+}
+
 /* Main entry point for the Tor process.  Called from tor_main(), and by
  * anybody embedding Tor. */
 int
@@ -1408,6 +1290,9 @@ tor_run_main(const tor_main_configuration_t *tor_cfg)
      }
   }
 #endif /* defined(NT_SERVICE) */
+
+  pubsub_install();
+
   {
     int init_rv = tor_init(argc, argv);
     if (init_rv) {
@@ -1417,6 +1302,8 @@ tor_run_main(const tor_main_configuration_t *tor_cfg)
     }
   }
 
+  pubsub_connect();
+
   if (get_options()->Sandbox && get_options()->command == CMD_RUN_TOR) {
     sandbox_cfg_t* cfg = sandbox_init_filter();
 
diff --git a/src/app/main/main.h b/src/app/main/main.h
index bbbbf984f..9dfaf4b8e 100644
--- a/src/app/main/main.h
+++ b/src/app/main/main.h
@@ -21,9 +21,6 @@ void release_lockfile(void);
 
 void tor_remove_file(const char *filename);
 
-void tor_cleanup(void);
-void tor_free_all(int postfork);
-
 int tor_init(int argc, char **argv);
 
 int run_tor_main_loop(void);
diff --git a/src/app/main/ntmain.c b/src/app/main/ntmain.c
index 05d203b0b..f00b71270 100644
--- a/src/app/main/ntmain.c
+++ b/src/app/main/ntmain.c
@@ -24,6 +24,7 @@
 #include "app/config/config.h"
 #include "app/main/main.h"
 #include "app/main/ntmain.h"
+#include "app/main/shutdown.h"
 #include "core/mainloop/mainloop.h"
 #include "lib/evloop/compat_libevent.h"
 #include "lib/fs/winlib.h"
diff --git a/src/app/main/shutdown.c b/src/app/main/shutdown.c
new file mode 100644
index 000000000..cc0091a9a
--- /dev/null
+++ b/src/app/main/shutdown.c
@@ -0,0 +1,169 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file shutdown.c
+ * @brief Code to free global resources used by Tor.
+ *
+ * In the future, this should all be handled by the subsystem manager. */
+
+#include "core/or/or.h"
+
+#include "app/config/config.h"
+#include "app/config/statefile.h"
+#include "app/main/main.h"
+#include "app/main/shutdown.h"
+#include "app/main/subsysmgr.h"
+#include "core/mainloop/connection.h"
+#include "core/mainloop/mainloop_pubsub.h"
+#include "core/or/channeltls.h"
+#include "core/or/circuitlist.h"
+#include "core/or/circuitmux_ewma.h"
+#include "core/or/circuitpadding.h"
+#include "core/or/connection_edge.h"
+#include "core/or/dos.h"
+#include "core/or/scheduler.h"
+#include "feature/client/addressmap.h"
+#include "feature/client/bridges.h"
+#include "feature/client/entrynodes.h"
+#include "feature/client/transports.h"
+#include "feature/control/control.h"
+#include "feature/control/control_auth.h"
+#include "feature/dirauth/authmode.h"
+#include "feature/dirauth/shared_random.h"
+#include "feature/dircache/consdiffmgr.h"
+#include "feature/dircache/dirserv.h"
+#include "feature/dirparse/routerparse.h"
+#include "feature/hibernate/hibernate.h"
+#include "feature/hs/hs_common.h"
+#include "feature/nodelist/microdesc.h"
+#include "feature/nodelist/networkstatus.h"
+#include "feature/nodelist/nodelist.h"
+#include "feature/nodelist/routerlist.h"
+#include "feature/nodelist/routerlist.h"
+#include "feature/relay/ext_orport.h"
+#include "feature/rend/rendcache.h"
+#include "feature/rend/rendclient.h"
+#include "feature/stats/geoip_stats.h"
+#include "feature/stats/rephist.h"
+#include "lib/evloop/compat_libevent.h"
+#include "lib/geoip/geoip.h"
+
+void evdns_shutdown(int);
+
+/** Do whatever cleanup is necessary before shutting Tor down. */
+void
+tor_cleanup(void)
+{
+  const or_options_t *options = get_options();
+  if (options->command == CMD_RUN_TOR) {
+    time_t now = time(NULL);
+    /* Remove our pid file. We don't care if there was an error when we
+     * unlink, nothing we could do about it anyways. */
+    tor_remove_file(options->PidFile);
+    /* Remove control port file */
+    tor_remove_file(options->ControlPortWriteToFile);
+    /* Remove cookie authentication file */
+    {
+      char *cookie_fname = get_controller_cookie_file_name();
+      tor_remove_file(cookie_fname);
+      tor_free(cookie_fname);
+    }
+    /* Remove Extended ORPort cookie authentication file */
+    {
+      char *cookie_fname = get_ext_or_auth_cookie_file_name();
+      tor_remove_file(cookie_fname);
+      tor_free(cookie_fname);
+    }
+    if (accounting_is_enabled(options))
+      accounting_record_bandwidth_usage(now, get_or_state());
+    or_state_mark_dirty(get_or_state(), 0); /* force an immediate save. */
+    or_state_save(now);
+    if (authdir_mode(options)) {
+      sr_save_and_cleanup();
+    }
+    if (authdir_mode_tests_reachability(options))
+      rep_hist_record_mtbf_data(now, 0);
+  }
+
+  timers_shutdown();
+
+  tor_free_all(0); /* We could move tor_free_all back into the ifdef below
+                      later, if it makes shutdown unacceptably slow.  But for
+                      now, leave it here: it's helped us catch bugs in the
+                      past. */
+}
+
+/** Free all memory that we might have allocated somewhere.
+ * If <b>postfork</b>, we are a worker process and we want to free
+ * only the parts of memory that we won't touch. If !<b>postfork</b>,
+ * Tor is shutting down and we should free everything.
+ *
+ * Helps us find the real leaks with sanitizers and the like. Also valgrind
+ * should then report 0 reachable in its leak report (in an ideal world --
+ * in practice libevent, SSL, libc etc never quite free everything). */
+void
+tor_free_all(int postfork)
+{
+  if (!postfork) {
+    evdns_shutdown(1);
+  }
+  geoip_free_all();
+  geoip_stats_free_all();
+  routerlist_free_all();
+  networkstatus_free_all();
+  addressmap_free_all();
+  dirserv_free_all();
+  rend_cache_free_all();
+  rend_service_authorization_free_all();
+  rep_hist_free_all();
+  circuit_free_all();
+  circpad_machines_free();
+  entry_guards_free_all();
+  pt_free_all();
+  channel_tls_free_all();
+  channel_free_all();
+  connection_free_all();
+  connection_edge_free_all();
+  scheduler_free_all();
+  nodelist_free_all();
+  microdesc_free_all();
+  routerparse_free_all();
+  control_free_all();
+  bridges_free_all();
+  consdiffmgr_free_all();
+  hs_free_all();
+  dos_free_all();
+  circuitmux_ewma_free_all();
+  accounting_free_all();
+  circpad_free_all();
+
+  if (!postfork) {
+    config_free_all();
+    or_state_free_all();
+  }
+  if (!postfork) {
+#ifndef _WIN32
+    tor_getpwnam(NULL);
+#endif
+  }
+  /* stuff in main.c */
+
+  tor_mainloop_disconnect_pubsub();
+
+  if (!postfork) {
+    release_lockfile();
+  }
+
+  subsystems_shutdown();
+
+  tor_libevent_free_all();
+
+  /* Stuff in util.c and address.c*/
+  if (!postfork) {
+    esc_router_info(NULL);
+  }
+}
diff --git a/src/app/main/shutdown.h b/src/app/main/shutdown.h
new file mode 100644
index 000000000..1bca96a0a
--- /dev/null
+++ b/src/app/main/shutdown.h
@@ -0,0 +1,18 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file shutdown.h
+ * \brief Header file for shutdown.c.
+ **/
+
+#ifndef TOR_SHUTDOWN_H
+#define TOR_SHUTDOWN_H
+
+void tor_cleanup(void);
+void tor_free_all(int postfork);
+
+#endif /* !defined(TOR_SHUTDOWN_H) */
diff --git a/src/app/main/subsysmgr.c b/src/app/main/subsysmgr.c
index e0ca3ce4d..5aa4fd76c 100644
--- a/src/app/main/subsysmgr.c
+++ b/src/app/main/subsysmgr.c
@@ -5,9 +5,14 @@
 
 #include "orconfig.h"
 #include "app/main/subsysmgr.h"
-#include "lib/err/torerr.h"
 
+#include "lib/dispatch/dispatch_naming.h"
+#include "lib/dispatch/msgtypes.h"
+#include "lib/err/torerr.h"
 #include "lib/log/log.h"
+#include "lib/malloc/malloc.h"
+#include "lib/pubsub/pubsub_build.h"
+#include "lib/pubsub/pubsub_connect.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -106,6 +111,51 @@ subsystems_init_upto(int target_level)
 }
 
 /**
+ * Add publish/subscribe relationships to <b>builder</b> for all
+ * initialized subsystems of level no more than <b>target_level</b>.
+ **/
+int
+subsystems_add_pubsub_upto(pubsub_builder_t *builder,
+                           int target_level)
+{
+  for (unsigned i = 0; i < n_tor_subsystems; ++i) {
+    const subsys_fns_t *sys = tor_subsystems[i];
+    if (!sys->supported)
+      continue;
+    if (sys->level > target_level)
+      break;
+    if (! sys_initialized[i])
+      continue;
+    int r = 0;
+    if (sys->add_pubsub) {
+      subsys_id_t sysid = get_subsys_id(sys->name);
+      raw_assert(sysid != ERROR_ID);
+      pubsub_connector_t *connector;
+      connector = pubsub_connector_for_subsystem(builder, sysid);
+      r = sys->add_pubsub(connector);
+      pubsub_connector_free(connector);
+    }
+    if (r < 0) {
+      fprintf(stderr, "BUG: subsystem %s (at %u) could not connect to "
+              "publish/subscribe system.", sys->name, sys->level);
+      raw_assert_unreached_msg("A subsystem couldn't be connected.");
+    }
+  }
+
+  return 0;
+}
+
+/**
+ * Add publish/subscribe relationships to <b>builder</b> for all
+ * initialized subsystems.
+ **/
+int
+subsystems_add_pubsub(pubsub_builder_t *builder)
+{
+  return subsystems_add_pubsub_upto(builder, MAX_SUBSYS_LEVEL);
+}
+
+/**
  * Shut down all the subsystems.
  **/
 void
diff --git a/src/app/main/subsysmgr.h b/src/app/main/subsysmgr.h
index a5e62f71d..d4426614e 100644
--- a/src/app/main/subsysmgr.h
+++ b/src/app/main/subsysmgr.h
@@ -14,6 +14,11 @@ extern const unsigned n_tor_subsystems;
 int subsystems_init(void);
 int subsystems_init_upto(int level);
 
+struct pubsub_builder_t;
+int subsystems_add_pubsub_upto(struct pubsub_builder_t *builder,
+                               int target_level);
+int subsystems_add_pubsub(struct pubsub_builder_t *builder);
+
 void subsystems_shutdown(void);
 void subsystems_shutdown_downto(int level);
 
@@ -21,4 +26,4 @@ void subsystems_prefork(void);
 void subsystems_postfork(void);
 void subsystems_thread_cleanup(void);
 
-#endif
+#endif /* !defined(TOR_SUBSYSMGR_T) */
diff --git a/src/app/main/subsystem_list.c b/src/app/main/subsystem_list.c
index 383417618..f59579623 100644
--- a/src/app/main/subsystem_list.c
+++ b/src/app/main/subsystem_list.c
@@ -8,20 +8,25 @@
 #include "lib/cc/compat_compiler.h"
 #include "lib/cc/torint.h"
 
+#include "core/mainloop/mainloop_sys.h"
 #include "core/or/ocirc_event_sys.h"
+#include "core/or/or_sys.h"
 #include "core/or/orconn_event_sys.h"
 #include "feature/control/btrack_sys.h"
+#include "feature/relay/relay_sys.h"
 #include "lib/compress/compress_sys.h"
 #include "lib/crypt_ops/crypto_sys.h"
 #include "lib/err/torerr_sys.h"
 #include "lib/log/log_sys.h"
 #include "lib/net/network_sys.h"
+#include "lib/process/process_sys.h"
 #include "lib/process/winprocess_sys.h"
 #include "lib/thread/thread_sys.h"
 #include "lib/time/time_sys.h"
 #include "lib/tls/tortls_sys.h"
 #include "lib/wallclock/wallclock_sys.h"
-#include "lib/process/process_sys.h"
+
+#include "feature/dirauth/dirauth_sys.h"
 
 #include <stddef.h>
 
@@ -44,6 +49,15 @@ const subsys_fns_t *tor_subsystems[] = {
   &sys_orconn_event, /* -33 */
   &sys_ocirc_event, /* -32 */
   &sys_btrack, /* -30 */
+
+  &sys_mainloop, /* 5 */
+  &sys_or, /* 20 */
+
+  &sys_relay, /* 50 */
+
+#ifdef HAVE_MODULE_DIRAUTH
+  &sys_dirauth, /* 70 */
+#endif
 };
 
 const unsigned n_tor_subsystems = ARRAY_LENGTH(tor_subsystems);
diff --git a/src/config/mmdb-convert.py b/src/config/mmdb-convert.py
index 706a8b03c..b861e9433 100644
--- a/src/config/mmdb-convert.py
+++ b/src/config/mmdb-convert.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/python
 
 #   This software has been dedicated to the public domain under the CC0
 #   public domain dedication.
diff --git a/src/config/torrc.sample.in b/src/config/torrc.sample.in
index c2ae707e9..9d514e6bd 100644
--- a/src/config/torrc.sample.in
+++ b/src/config/torrc.sample.in
@@ -174,13 +174,11 @@
 
 ## Uncomment this if you want your relay to be an exit, with the default
 ## exit policy (or whatever exit policy you set below).
-## (If ReducedExitPolicy or ExitPolicy are set, relays are exits.
-## If neither exit policy option is set, relays are non-exits.)
+## (If ReducedExitPolicy, ExitPolicy, or IPv6Exit are set, relays are exits.
+## If none of these options are set, relays are non-exits.)
 #ExitRelay 1
 
 ## Uncomment this if you want your relay to allow IPv6 exit traffic.
-## You must also set ExitRelay, ReducedExitPolicy, or ExitPolicy to make your
-## relay into an exit.
 ## (Relays do not allow any exit traffic by default.)
 #IPv6Exit 1
 
diff --git a/src/core/crypto/hs_ntor.c b/src/core/crypto/hs_ntor.c
index c34073690..add8a2b8f 100644
--- a/src/core/crypto/hs_ntor.c
+++ b/src/core/crypto/hs_ntor.c
@@ -176,7 +176,6 @@ get_introduce1_key_material(const uint8_t *secret_input,
   uint8_t keystream[CIPHER256_KEY_LEN + DIGEST256_LEN];
   uint8_t info_blob[INFO_BLOB_LEN];
   uint8_t kdf_input[KDF_INPUT_LEN];
-  crypto_xof_t *xof;
   uint8_t *ptr;
 
   /* Let's build info */
@@ -193,10 +192,8 @@ get_introduce1_key_material(const uint8_t *secret_input,
   tor_assert(ptr == kdf_input + sizeof(kdf_input));
 
   /* Now we need to run kdf_input over SHAKE-256 */
-  xof = crypto_xof_new();
-  crypto_xof_add_bytes(xof, kdf_input, sizeof(kdf_input));
-  crypto_xof_squeeze_bytes(xof, keystream, sizeof(keystream)) ;
-  crypto_xof_free(xof);
+  crypto_xof(keystream, sizeof(keystream),
+             kdf_input, sizeof(kdf_input));
 
   { /* Get the keys */
     memcpy(&hs_ntor_intro_cell_keys_out->enc_key, keystream,CIPHER256_KEY_LEN);
@@ -594,7 +591,6 @@ hs_ntor_circuit_key_expansion(const uint8_t *ntor_key_seed, size_t seed_len,
 {
   uint8_t *ptr;
   uint8_t kdf_input[NTOR_KEY_EXPANSION_KDF_INPUT_LEN];
-  crypto_xof_t *xof;
 
   /* Sanity checks on lengths to make sure we are good */
   if (BUG(seed_len != DIGEST256_LEN)) {
@@ -611,10 +607,8 @@ hs_ntor_circuit_key_expansion(const uint8_t *ntor_key_seed, size_t seed_len,
   tor_assert(ptr == kdf_input + sizeof(kdf_input));
 
   /* Generate the keys */
-  xof = crypto_xof_new();
-  crypto_xof_add_bytes(xof, kdf_input, sizeof(kdf_input));
-  crypto_xof_squeeze_bytes(xof, keys_out, HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN);
-  crypto_xof_free(xof);
+  crypto_xof(keys_out, HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN,
+             kdf_input, sizeof(kdf_input));
 
   return 0;
 }
diff --git a/src/core/crypto/onion_crypto.h b/src/core/crypto/onion_crypto.h
index 1cddde361..7abdd6538 100644
--- a/src/core/crypto/onion_crypto.h
+++ b/src/core/crypto/onion_crypto.h
@@ -44,4 +44,4 @@ void server_onion_keys_free_(server_onion_keys_t *keys);
 #define server_onion_keys_free(keys) \
   FREE_AND_NULL(server_onion_keys_t, server_onion_keys_free_, (keys))
 
-#endif
+#endif /* !defined(TOR_ONION_CRYPTO_H) */
diff --git a/src/core/crypto/relay_crypto.c b/src/core/crypto/relay_crypto.c
index 0b83b2d0a..8a285131a 100644
--- a/src/core/crypto/relay_crypto.c
+++ b/src/core/crypto/relay_crypto.c
@@ -6,12 +6,14 @@
 
 #include "core/or/or.h"
 #include "core/or/circuitlist.h"
+#include "core/or/crypt_path.h"
 #include "app/config/config.h"
 #include "lib/crypt_ops/crypto_cipher.h"
 #include "lib/crypt_ops/crypto_util.h"
 #include "core/crypto/hs_ntor.h" // for HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN
 #include "core/or/relay.h"
 #include "core/crypto/relay_crypto.h"
+#include "core/or/sendme.h"
 
 #include "core/or/cell_st.h"
 #include "core/or/or_circuit_st.h"
@@ -20,7 +22,7 @@
 /** Update digest from the payload of cell. Assign integrity part to
  * cell.
  */
-static void
+void
 relay_set_digest(crypto_digest_t *digest, cell_t *cell)
 {
   char integrity[4];
@@ -84,12 +86,39 @@ relay_digest_matches(crypto_digest_t *digest, cell_t *cell)
  *
  * Note that we use the same operation for encrypting and for decrypting.
  */
-static void
+void
 relay_crypt_one_payload(crypto_cipher_t *cipher, uint8_t *in)
 {
   crypto_cipher_crypt_inplace(cipher, (char*) in, CELL_PAYLOAD_SIZE);
 }
 
+/** Return the sendme_digest within the <b>crypto</b> object. */
+uint8_t *
+relay_crypto_get_sendme_digest(relay_crypto_t *crypto)
+{
+  tor_assert(crypto);
+  return crypto->sendme_digest;
+}
+
+/** Record the cell digest, indicated by is_foward_digest or not, as the
+ * SENDME cell digest. */
+void
+relay_crypto_record_sendme_digest(relay_crypto_t *crypto,
+                                  bool is_foward_digest)
+{
+  struct crypto_digest_t *digest;
+
+  tor_assert(crypto);
+
+  digest = crypto->b_digest;
+  if (is_foward_digest) {
+    digest = crypto->f_digest;
+  }
+
+  crypto_digest_get_digest(digest, (char *) crypto->sendme_digest,
+                           sizeof(crypto->sendme_digest));
+}
+
 /** Do the appropriate en/decryptions for <b>cell</b> arriving on
  * <b>circ</b> in direction <b>cell_direction</b>.
  *
@@ -134,12 +163,12 @@ relay_decrypt_cell(circuit_t *circ, cell_t *cell,
         tor_assert(thishop);
 
         /* decrypt one layer */
-        relay_crypt_one_payload(thishop->crypto.b_crypto, cell->payload);
+        cpath_crypt_cell(thishop, cell->payload, true);
 
         relay_header_unpack(&rh, cell->payload);
         if (rh.recognized == 0) {
           /* it's possibly recognized. have to check digest to be sure. */
-          if (relay_digest_matches(thishop->crypto.b_digest, cell)) {
+          if (relay_digest_matches(cpath_get_incoming_digest(thishop), cell)) {
             *recognized = 1;
             *layer_hint = thishop;
             return 0;
@@ -187,14 +216,17 @@ relay_encrypt_cell_outbound(cell_t *cell,
                             crypt_path_t *layer_hint)
 {
   crypt_path_t *thishop; /* counter for repeated crypts */
-  relay_set_digest(layer_hint->crypto.f_digest, cell);
+  cpath_set_cell_forward_digest(layer_hint, cell);
+
+  /* Record cell digest as the SENDME digest if need be. */
+  sendme_record_sending_cell_digest(TO_CIRCUIT(circ), layer_hint);
 
   thishop = layer_hint;
   /* moving from farthest to nearest hop */
   do {
     tor_assert(thishop);
     log_debug(LD_OR,"encrypting a layer of the relay cell.");
-    relay_crypt_one_payload(thishop->crypto.f_crypto, cell->payload);
+    cpath_crypt_cell(thishop, cell->payload, false);
 
     thishop = thishop->prev;
   } while (thishop != circ->cpath->prev);
@@ -212,6 +244,10 @@ relay_encrypt_cell_inbound(cell_t *cell,
                            or_circuit_t *or_circ)
 {
   relay_set_digest(or_circ->crypto.b_digest, cell);
+
+  /* Record cell digest as the SENDME digest if need be. */
+  sendme_record_sending_cell_digest(TO_CIRCUIT(or_circ), NULL);
+
   /* encrypt one layer */
   relay_crypt_one_payload(or_circ->crypto.b_crypto, cell->payload);
 }
diff --git a/src/core/crypto/relay_crypto.h b/src/core/crypto/relay_crypto.h
index 45a21d14a..9478f8d35 100644
--- a/src/core/crypto/relay_crypto.h
+++ b/src/core/crypto/relay_crypto.h
@@ -27,5 +27,16 @@ void relay_crypto_clear(relay_crypto_t *crypto);
 
 void relay_crypto_assert_ok(const relay_crypto_t *crypto);
 
+uint8_t *relay_crypto_get_sendme_digest(relay_crypto_t *crypto);
+
+void relay_crypto_record_sendme_digest(relay_crypto_t *crypto,
+                                       bool is_foward_digest);
+
+void
+relay_crypt_one_payload(crypto_cipher_t *cipher, uint8_t *in);
+
+void
+relay_set_digest(crypto_digest_t *digest, cell_t *cell);
+
 #endif /* !defined(TOR_RELAY_CRYPTO_H) */
 
diff --git a/src/core/include.am b/src/core/include.am
index ae47c75e0..1a4b9fb8a 100644
--- a/src/core/include.am
+++ b/src/core/include.am
@@ -6,11 +6,13 @@ noinst_LIBRARIES += \
 	src/core/libtor-app-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 LIBTOR_APP_A_SOURCES = 				\
 	src/app/config/config.c			\
 	src/app/config/confparse.c		\
 	src/app/config/statefile.c		\
 	src/app/main/main.c			\
+	src/app/main/shutdown.c			\
 	src/app/main/subsystem_list.c		\
 	src/app/main/subsysmgr.c		\
 	src/core/crypto/hs_ntor.c		\
@@ -22,6 +24,8 @@ LIBTOR_APP_A_SOURCES = 				\
 	src/core/mainloop/connection.c		\
 	src/core/mainloop/cpuworker.c		\
 	src/core/mainloop/mainloop.c		\
+	src/core/mainloop/mainloop_pubsub.c	\
+	src/core/mainloop/mainloop_sys.c	\
 	src/core/mainloop/netstatus.c		\
 	src/core/mainloop/periodic.c		\
 	src/core/or/address_set.c		\
@@ -33,14 +37,18 @@ LIBTOR_APP_A_SOURCES = 				\
 	src/core/or/circuitmux.c		\
 	src/core/or/circuitmux_ewma.c		\
 	src/core/or/circuitpadding.c		\
+	src/core/or/circuitpadding_machines.c	\
 	src/core/or/circuitstats.c		\
 	src/core/or/circuituse.c		\
+	src/core/or/crypt_path.c		\
 	src/core/or/command.c			\
 	src/core/or/connection_edge.c		\
 	src/core/or/connection_or.c		\
 	src/core/or/dos.c			\
 	src/core/or/onion.c			\
 	src/core/or/ocirc_event.c		\
+	src/core/or/or_periodic.c		\
+	src/core/or/or_sys.c			\
 	src/core/or/orconn_event.c		\
 	src/core/or/policies.c			\
 	src/core/or/protover.c			\
@@ -50,6 +58,7 @@ LIBTOR_APP_A_SOURCES = 				\
 	src/core/or/scheduler.c			\
 	src/core/or/scheduler_kist.c		\
 	src/core/or/scheduler_vanilla.c		\
+	src/core/or/sendme.c			\
 	src/core/or/status.c			\
 	src/core/or/versions.c			\
 	src/core/proto/proto_cell.c		\
@@ -70,10 +79,15 @@ LIBTOR_APP_A_SOURCES = 				\
 	src/feature/control/btrack_orconn_cevent.c	\
 	src/feature/control/btrack_orconn_maps.c	\
 	src/feature/control/control.c		\
+	src/feature/control/control_auth.c	\
 	src/feature/control/control_bootstrap.c	\
+	src/feature/control/control_cmd.c	\
+	src/feature/control/control_events.c	\
+	src/feature/control/control_fmt.c	\
+	src/feature/control/control_getinfo.c	\
+	src/feature/control/control_proto.c	\
 	src/feature/control/fmt_serverstatus.c  \
 	src/feature/control/getinfo_geoip.c	\
-	src/feature/dirauth/keypin.c		\
 	src/feature/dircache/conscache.c	\
 	src/feature/dircache/consdiffmgr.c	\
 	src/feature/dircache/dircache.c		\
@@ -110,7 +124,6 @@ LIBTOR_APP_A_SOURCES = 				\
 	src/feature/hs_common/replaycache.c	\
 	src/feature/hs_common/shared_random_client.c	\
 	src/feature/keymgt/loadkey.c		\
-	src/feature/dirauth/keypin.c		\
 	src/feature/nodelist/authcert.c		\
 	src/feature/nodelist/describe.c		\
 	src/feature/nodelist/dirlist.c		\
@@ -128,6 +141,8 @@ LIBTOR_APP_A_SOURCES = 				\
 	src/feature/relay/dns.c			\
 	src/feature/relay/ext_orport.c		\
 	src/feature/relay/onion_queue.c		\
+	src/feature/relay/relay_periodic.c	\
+	src/feature/relay/relay_sys.c		\
 	src/feature/relay/router.c		\
 	src/feature/relay/routerkeys.c		\
 	src/feature/relay/routermode.c		\
@@ -142,17 +157,6 @@ LIBTOR_APP_A_SOURCES = 				\
 	src/feature/stats/rephist.c		\
 	src/feature/stats/predict_ports.c
 
-# These should eventually move into module_dirauth_sources, but for now
-# the separation is only in the code location.
-LIBTOR_APP_A_SOURCES += 			\
-	src/feature/dirauth/bwauth.c		\
-	src/feature/dirauth/dsigs_parse.c	\
-	src/feature/dirauth/guardfraction.c	\
-	src/feature/dirauth/reachability.c	\
-	src/feature/dirauth/recommend_pkg.c	\
-	src/feature/dirauth/process_descs.c	\
-	src/feature/dirauth/voteflags.c
-
 if BUILD_NT_SERVICES
 LIBTOR_APP_A_SOURCES += src/app/main/ntmain.c
 endif
@@ -168,10 +172,21 @@ LIBTOR_APP_TESTING_A_SOURCES = $(LIBTOR_APP_A_SOURCES)
 # The Directory Authority module.
 MODULE_DIRAUTH_SOURCES = 					\
 	src/feature/dirauth/authmode.c				\
+	src/feature/dirauth/bridgeauth.c			\
+	src/feature/dirauth/bwauth.c				\
+	src/feature/dirauth/dirauth_periodic.c			\
+	src/feature/dirauth/dirauth_sys.c			\
 	src/feature/dirauth/dircollate.c			\
 	src/feature/dirauth/dirvote.c				\
+	src/feature/dirauth/dsigs_parse.c			\
+	src/feature/dirauth/guardfraction.c			\
+	src/feature/dirauth/keypin.c				\
+	src/feature/dirauth/process_descs.c			\
+	src/feature/dirauth/reachability.c			\
+	src/feature/dirauth/recommend_pkg.c			\
 	src/feature/dirauth/shared_random.c			\
-	src/feature/dirauth/shared_random_state.c
+	src/feature/dirauth/shared_random_state.c		\
+	src/feature/dirauth/voteflags.c
 
 if BUILD_MODULE_DIRAUTH
 LIBTOR_APP_A_SOURCES += $(MODULE_DIRAUTH_SOURCES)
@@ -195,6 +210,7 @@ AM_CPPFLAGS += -DSHARE_DATADIR="\"$(datadir)\""		\
 src_core_libtor_app_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_core_libtor_app_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/app/config/config.h				\
 	src/app/config/confparse.h			\
@@ -203,6 +219,7 @@ noinst_HEADERS +=					\
 	src/app/config/statefile.h			\
 	src/app/main/main.h				\
 	src/app/main/ntmain.h				\
+	src/app/main/shutdown.h 			\
 	src/app/main/subsysmgr.h			\
 	src/core/crypto/hs_ntor.h			\
 	src/core/crypto/onion_crypto.h	        	\
@@ -213,6 +230,8 @@ noinst_HEADERS +=					\
 	src/core/mainloop/connection.h			\
 	src/core/mainloop/cpuworker.h			\
 	src/core/mainloop/mainloop.h			\
+	src/core/mainloop/mainloop_pubsub.h		\
+	src/core/mainloop/mainloop_sys.h		\
 	src/core/mainloop/netstatus.h			\
 	src/core/mainloop/periodic.h			\
 	src/core/or/addr_policy_st.h			\
@@ -229,24 +248,28 @@ noinst_HEADERS +=					\
 	src/core/or/circuitmux_ewma.h			\
 	src/core/or/circuitstats.h			\
 	src/core/or/circuitpadding.h			\
+	src/core/or/circuitpadding_machines.h		\
 	src/core/or/circuituse.h			\
 	src/core/or/command.h				\
 	src/core/or/connection_edge.h			\
 	src/core/or/connection_or.h			\
 	src/core/or/connection_st.h			\
+	src/core/or/crypt_path.h			\
 	src/core/or/cpath_build_state_st.h		\
 	src/core/or/crypt_path_reference_st.h		\
 	src/core/or/crypt_path_st.h			\
 	src/core/or/destroy_cell_queue_st.h		\
 	src/core/or/dos.h				\
 	src/core/or/edge_connection_st.h		\
-	src/core/or/half_edge_st.h		\
+	src/core/or/half_edge_st.h			\
 	src/core/or/entry_connection_st.h		\
 	src/core/or/entry_port_cfg_st.h			\
 	src/core/or/extend_info_st.h			\
 	src/core/or/listener_connection_st.h		\
 	src/core/or/onion.h				\
 	src/core/or/or.h				\
+	src/core/or/or_periodic.h			\
+	src/core/or/or_sys.h				\
 	src/core/or/orconn_event.h			\
 	src/core/or/orconn_event_sys.h			\
 	src/core/or/or_circuit_st.h			\
@@ -263,6 +286,7 @@ noinst_HEADERS +=					\
 	src/core/or/relay.h				\
 	src/core/or/relay_crypto_st.h			\
 	src/core/or/scheduler.h				\
+	src/core/or/sendme.h				\
 	src/core/or/server_port_cfg_st.h		\
 	src/core/or/socks_request_st.h			\
 	src/core/or/status.h				\
@@ -287,11 +311,21 @@ noinst_HEADERS +=					\
 	src/feature/control/btrack_orconn_maps.h	\
 	src/feature/control/btrack_sys.h		\
 	src/feature/control/control.h			\
+	src/feature/control/control_auth.h		\
+	src/feature/control/control_cmd.h		\
+	src/feature/control/control_cmd_args_st.h	\
 	src/feature/control/control_connection_st.h	\
+	src/feature/control/control_events.h		\
+	src/feature/control/control_fmt.h		\
+	src/feature/control/control_getinfo.h		\
+	src/feature/control/control_proto.h		\
 	src/feature/control/fmt_serverstatus.h		\
 	src/feature/control/getinfo_geoip.h		\
 	src/feature/dirauth/authmode.h			\
+        src/feature/dirauth/bridgeauth.h		\
 	src/feature/dirauth/bwauth.h			\
+	src/feature/dirauth/dirauth_periodic.h		\
+	src/feature/dirauth/dirauth_sys.h		\
 	src/feature/dirauth/dircollate.h		\
 	src/feature/dirauth/dirvote.h			\
 	src/feature/dirauth/dsigs_parse.h		\
@@ -363,8 +397,8 @@ noinst_HEADERS +=					\
 	src/feature/nodelist/networkstatus_voter_info_st.h	\
 	src/feature/nodelist/nickname.h			\
 	src/feature/nodelist/node_st.h			\
-	src/feature/nodelist/nodefamily.h	        \
-	src/feature/nodelist/nodefamily_st.h    	\
+	src/feature/nodelist/nodefamily.h		\
+	src/feature/nodelist/nodefamily_st.h		\
 	src/feature/nodelist/nodelist.h			\
 	src/feature/nodelist/node_select.h		\
 	src/feature/nodelist/routerinfo.h		\
@@ -381,6 +415,8 @@ noinst_HEADERS +=					\
 	src/feature/relay/dns_structs.h			\
 	src/feature/relay/ext_orport.h			\
 	src/feature/relay/onion_queue.h			\
+	src/feature/relay/relay_periodic.h		\
+	src/feature/relay/relay_sys.h			\
 	src/feature/relay/router.h			\
 	src/feature/relay/routerkeys.h			\
 	src/feature/relay/routermode.h			\
diff --git a/src/core/mainloop/connection.c b/src/core/mainloop/connection.c
index df0bb39db..127f08683 100644
--- a/src/core/mainloop/connection.c
+++ b/src/core/mainloop/connection.c
@@ -82,12 +82,14 @@
 #include "core/or/policies.h"
 #include "core/or/reasons.h"
 #include "core/or/relay.h"
+#include "core/or/crypt_path.h"
 #include "core/proto/proto_http.h"
 #include "core/proto/proto_socks.h"
 #include "feature/client/dnsserv.h"
 #include "feature/client/entrynodes.h"
 #include "feature/client/transports.h"
 #include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/authmode.h"
 #include "feature/dircache/dirserv.h"
 #include "feature/dircommon/directory.h"
@@ -182,7 +184,7 @@ static const char *connection_proxy_state_to_string(int state);
 static int connection_read_https_proxy_response(connection_t *conn);
 static void connection_send_socks5_connect(connection_t *conn);
 static const char *proxy_type_to_string(int proxy_type);
-static int get_proxy_type(void);
+static int conn_get_proxy_type(const connection_t *conn);
 const tor_addr_t *conn_get_outbound_address(sa_family_t family,
                   const or_options_t *options, unsigned int conn_type);
 static void reenable_blocked_connection_init(const or_options_t *options);
@@ -696,6 +698,7 @@ connection_free_minimal(connection_t *conn)
     control_connection_t *control_conn = TO_CONTROL_CONN(conn);
     tor_free(control_conn->safecookie_client_hash);
     tor_free(control_conn->incoming_cmd);
+    tor_free(control_conn->current_cmd);
     if (control_conn->ephemeral_onion_services) {
       SMARTLIST_FOREACH(control_conn->ephemeral_onion_services, char *, cp, {
         memwipe(cp, 0, strlen(cp));
@@ -1473,7 +1476,7 @@ connection_listener_new(const struct sockaddr *listensockaddr,
         goto err;
       }
     }
-#endif /* __APPLE__ */
+#endif /* !defined(__APPLE__) */
 #endif /* defined(HAVE_SYS_UN_H) */
   } else {
     log_err(LD_BUG, "Got unexpected address family %d.",
@@ -1652,7 +1655,7 @@ check_sockaddr(const struct sockaddr *sa, int len, int level)
              len,(int)sizeof(struct sockaddr_in6));
       ok = 0;
     }
-    if (tor_mem_is_zero((void*)sin6->sin6_addr.s6_addr, 16) ||
+    if (fast_mem_is_zero((void*)sin6->sin6_addr.s6_addr, 16) ||
         sin6->sin6_port == 0) {
       log_fn(level, LD_NET,
              "Address for new connection has address/port equal to zero.");
@@ -2282,18 +2285,27 @@ connection_proxy_state_to_string(int state)
   return states[state];
 }
 
-/** Returns the global proxy type used by tor. Use this function for
- *  logging or high-level purposes, don't use it to fill the
+/** Returns the proxy type used by tor for a single connection, for
+ *  logging or high-level purposes. Don't use it to fill the
  *  <b>proxy_type</b> field of or_connection_t; use the actual proxy
  *  protocol instead.*/
 static int
-get_proxy_type(void)
+conn_get_proxy_type(const connection_t *conn)
 {
   const or_options_t *options = get_options();
 
-  if (options->ClientTransportPlugin)
-    return PROXY_PLUGGABLE;
-  else if (options->HTTPSProxy)
+  if (options->ClientTransportPlugin) {
+    /* If we have plugins configured *and* this addr/port is a known bridge
+     * with a transport, then we should be PROXY_PLUGGABLE. */
+    const transport_t *transport = NULL;
+    int r;
+    r = get_transport_by_bridge_addrport(&conn->addr, conn->port, &transport);
+    if (r == 0 && transport)
+      return PROXY_PLUGGABLE;
+  }
+
+  /* In all other cases, we're using a global proxy. */
+  if (options->HTTPSProxy)
     return PROXY_CONNECT;
   else if (options->Socks4Proxy)
     return PROXY_SOCKS4;
@@ -2380,7 +2392,7 @@ connection_proxy_connect(connection_t *conn, int type)
            arguments to transmit. If we do, compress all arguments to
            a single string in 'socks_args_string': */
 
-        if (get_proxy_type() == PROXY_PLUGGABLE) {
+        if (conn_get_proxy_type(conn) == PROXY_PLUGGABLE) {
           socks_args_string =
             pt_get_socks_args_for_proxy_addrport(&conn->addr, conn->port);
           if (socks_args_string)
@@ -2440,7 +2452,7 @@ connection_proxy_connect(connection_t *conn, int type)
          Socks5ProxyUsername or if we want to pass arguments to our
          pluggable transport proxy: */
       if ((options->Socks5ProxyUsername) ||
-          (get_proxy_type() == PROXY_PLUGGABLE &&
+          (conn_get_proxy_type(conn) == PROXY_PLUGGABLE &&
            (get_socks_args_by_bridge_addrport(&conn->addr, conn->port)))) {
       /* number of auth methods */
         buf[1] = 2;
@@ -2633,16 +2645,16 @@ connection_read_proxy_handshake(connection_t *conn)
         const char *user, *pass;
         char *socks_args_string = NULL;
 
-        if (get_proxy_type() == PROXY_PLUGGABLE) {
+        if (conn_get_proxy_type(conn) == PROXY_PLUGGABLE) {
           socks_args_string =
             pt_get_socks_args_for_proxy_addrport(&conn->addr, conn->port);
           if (!socks_args_string) {
-            log_warn(LD_NET, "Could not create SOCKS args string.");
+            log_warn(LD_NET, "Could not create SOCKS args string for PT.");
             ret = -1;
             break;
           }
 
-          log_debug(LD_NET, "SOCKS5 arguments: %s", socks_args_string);
+          log_debug(LD_NET, "PT SOCKS5 arguments: %s", socks_args_string);
           tor_assert(strlen(socks_args_string) > 0);
           tor_assert(strlen(socks_args_string) <= MAX_SOCKS5_AUTH_SIZE_TOTAL);
 
@@ -2844,7 +2856,7 @@ retry_listener_ports(smartlist_t *old_conns,
           SMARTLIST_DEL_CURRENT(old_conns, conn);
           break;
         }
-#endif
+#endif /* defined(ENABLE_LISTENER_REBIND) */
       }
     } SMARTLIST_FOREACH_END(wanted);
 
@@ -2946,7 +2958,7 @@ retry_all_listeners(smartlist_t *new_conns, int close_all_noncontrol)
                conn_type_to_string(old_conn->type), old_conn->address,
                old_conn->port, new_conn->address, new_conn->port);
   } SMARTLIST_FOREACH_END(r);
-#endif
+#endif /* defined(ENABLE_LISTENER_REBIND) */
 
   /* Any members that were still in 'listeners' don't correspond to
    * any configured port.  Kill 'em. */
@@ -3945,9 +3957,9 @@ update_send_buffer_size(tor_socket_t sock)
       &isb, sizeof(isb), &bytesReturned, NULL, NULL)) {
     setsockopt(sock, SOL_SOCKET, SO_SNDBUF, (const char*)&isb, sizeof(isb));
   }
-#else
+#else /* !(defined(_WIN32)) */
   (void) sock;
-#endif
+#endif /* defined(_WIN32) */
 }
 
 /** Try to flush more bytes onto <b>conn</b>-\>s.
@@ -5328,7 +5340,7 @@ assert_connection_ok(connection_t *conn, time_t now)
         tor_assert(entry_conn->socks_request->has_finished);
         if (!conn->marked_for_close) {
           tor_assert(ENTRY_TO_EDGE_CONN(entry_conn)->cpath_layer);
-          assert_cpath_layer_ok(ENTRY_TO_EDGE_CONN(entry_conn)->cpath_layer);
+          cpath_assert_layer_ok(ENTRY_TO_EDGE_CONN(entry_conn)->cpath_layer);
         }
       }
     }
diff --git a/src/core/mainloop/cpuworker.c b/src/core/mainloop/cpuworker.c
index e704d5564..436fcd28c 100644
--- a/src/core/mainloop/cpuworker.c
+++ b/src/core/mainloop/cpuworker.c
@@ -34,7 +34,6 @@
 #include "core/crypto/onion_crypto.h"
 
 #include "core/or/or_circuit_st.h"
-#include "lib/intmath/weakrng.h"
 
 static void queue_pending_tasks(void);
 
@@ -74,8 +73,6 @@ worker_state_free_void(void *arg)
 static replyqueue_t *replyqueue = NULL;
 static threadpool_t *threadpool = NULL;
 
-static tor_weak_rng_t request_sample_rng = TOR_WEAK_RNG_INIT;
-
 static int total_pending_tasks = 0;
 static int max_pending_tasks = 128;
 
@@ -109,7 +106,6 @@ cpu_init(void)
 
   /* Total voodoo. Can we make this more sensible? */
   max_pending_tasks = get_num_cpus(get_options()) * 64;
-  crypto_seed_weak_rng(&request_sample_rng);
 }
 
 /** Magic numbers to make sure our cpuworker_requests don't grow any
@@ -235,9 +231,10 @@ should_time_request(uint16_t onionskin_type)
    * sample */
   if (onionskins_n_processed[onionskin_type] < 4096)
     return 1;
+
   /** Otherwise, measure with P=1/128.  We avoid doing this for every
    * handshake, since the measurement itself can take a little time. */
-  return tor_weak_random_one_in_n(&request_sample_rng, 128);
+  return crypto_fast_rng_one_in_n(get_thread_fast_rng(), 128);
 }
 
 /** Return an estimate of how many microseconds we will need for a single
diff --git a/src/core/mainloop/mainloop.c b/src/core/mainloop/mainloop.c
index 18e87fa87..c051b1156 100644
--- a/src/core/mainloop/mainloop.c
+++ b/src/core/mainloop/mainloop.c
@@ -73,8 +73,8 @@
 #include "feature/client/entrynodes.h"
 #include "feature/client/transports.h"
 #include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/authmode.h"
-#include "feature/dirauth/reachability.h"
 #include "feature/dircache/consdiffmgr.h"
 #include "feature/dircache/dirserv.h"
 #include "feature/dircommon/directory.h"
@@ -105,9 +105,6 @@
 
 #include <event2/event.h>
 
-#include "feature/dirauth/dirvote.h"
-#include "feature/dirauth/authmode.h"
-
 #include "core/or/cell_st.h"
 #include "core/or/entry_connection_st.h"
 #include "feature/nodelist/networkstatus_st.h"
@@ -757,7 +754,7 @@ tor_shutdown_event_loop_for_restart_cb(
   tor_event_free(tor_shutdown_event_loop_for_restart_event);
   tor_shutdown_event_loop_and_exit(0);
 }
-#endif
+#endif /* defined(ENABLE_RESTART_DEBUGGING) */
 
 /**
  * After finishing the current callback (if any), shut down the main loop,
@@ -1345,36 +1342,20 @@ static int periodic_events_initialized = 0;
 #define CALLBACK(name) \
   static int name ## _callback(time_t, const or_options_t *)
 CALLBACK(add_entropy);
-CALLBACK(check_authority_cert);
-CALLBACK(check_canonical_channels);
-CALLBACK(check_descriptor);
-CALLBACK(check_dns_honesty);
-CALLBACK(check_ed_keys);
 CALLBACK(check_expired_networkstatus);
-CALLBACK(check_for_reachability_bw);
-CALLBACK(check_onion_keys_expiry_time);
 CALLBACK(clean_caches);
 CALLBACK(clean_consdiffmgr);
-CALLBACK(dirvote);
-CALLBACK(downrate_stability);
-CALLBACK(expire_old_ciruits_serverside);
 CALLBACK(fetch_networkstatus);
 CALLBACK(heartbeat);
 CALLBACK(hs_service);
 CALLBACK(launch_descriptor_fetches);
-CALLBACK(launch_reachability_tests);
 CALLBACK(prune_old_routers);
-CALLBACK(reachability_warnings);
 CALLBACK(record_bridge_stats);
 CALLBACK(rend_cache_failure_clean);
 CALLBACK(reset_padding_counts);
-CALLBACK(retry_dns);
 CALLBACK(retry_listeners);
-CALLBACK(rotate_onion_key);
 CALLBACK(rotate_x509_certificate);
-CALLBACK(save_stability);
 CALLBACK(save_state);
-CALLBACK(write_bridge_ns);
 CALLBACK(write_stats_file);
 CALLBACK(control_per_second_events);
 CALLBACK(second_elapsed);
@@ -1386,7 +1367,7 @@ CALLBACK(second_elapsed);
   PERIODIC_EVENT(name, PERIODIC_EVENT_ROLE_ ## r, f)
 #define FL(name) (PERIODIC_EVENT_FLAG_ ## name)
 
-STATIC periodic_event_item_t periodic_events[] = {
+STATIC periodic_event_item_t mainloop_periodic_events[] = {
 
   /* Everyone needs to run these. They need to have very long timeouts for
    * that to be safe. */
@@ -1417,29 +1398,6 @@ STATIC periodic_event_item_t periodic_events[] = {
   CALLBACK(write_stats_file, NET_PARTICIPANT, FL(RUN_ON_DISABLE)),
   CALLBACK(prune_old_routers, NET_PARTICIPANT, FL(RUN_ON_DISABLE)),
 
-  /* Routers (bridge and relay) only. */
-  CALLBACK(check_descriptor, ROUTER, FL(NEED_NET)),
-  CALLBACK(check_ed_keys, ROUTER, 0),
-  CALLBACK(check_for_reachability_bw, ROUTER, FL(NEED_NET)),
-  CALLBACK(check_onion_keys_expiry_time, ROUTER, 0),
-  CALLBACK(expire_old_ciruits_serverside, ROUTER, FL(NEED_NET)),
-  CALLBACK(reachability_warnings, ROUTER, FL(NEED_NET)),
-  CALLBACK(retry_dns, ROUTER, 0),
-  CALLBACK(rotate_onion_key, ROUTER, 0),
-
-  /* Authorities (bridge and directory) only. */
-  CALLBACK(downrate_stability, AUTHORITIES, 0),
-  CALLBACK(launch_reachability_tests, AUTHORITIES, FL(NEED_NET)),
-  CALLBACK(save_stability, AUTHORITIES, 0),
-
-  /* Directory authority only. */
-  CALLBACK(check_authority_cert, DIRAUTH, 0),
-  CALLBACK(dirvote, DIRAUTH, FL(NEED_NET)),
-
-  /* Relay only. */
-  CALLBACK(check_canonical_channels, RELAY, FL(NEED_NET)),
-  CALLBACK(check_dns_honesty, RELAY, FL(NEED_NET)),
-
   /* Hidden Service service only. */
   CALLBACK(hs_service, HS_SERVICE, FL(NEED_NET)), // XXXX break this down more
 
@@ -1450,9 +1408,6 @@ STATIC periodic_event_item_t periodic_events[] = {
   /* XXXX this could be restricted to CLIENT+NET_PARTICIPANT */
   CALLBACK(rend_cache_failure_clean, NET_PARTICIPANT, FL(RUN_ON_DISABLE)),
 
-  /* Bridge Authority only. */
-  CALLBACK(write_bridge_ns, BRIDGEAUTH, 0),
-
   /* Directory server only. */
   CALLBACK(clean_consdiffmgr, DIRSERVER, 0),
 
@@ -1468,8 +1423,6 @@ STATIC periodic_event_item_t periodic_events[] = {
  * implement particular callbacks.  We keep them separate here so that we
  * can access them by name.  We also keep them inside periodic_events[]
  * so that we can implement "reset all timers" in a reasonable way. */
-static periodic_event_item_t *check_descriptor_event=NULL;
-static periodic_event_item_t *dirvote_event=NULL;
 static periodic_event_item_t *fetch_networkstatus_event=NULL;
 static periodic_event_item_t *launch_descriptor_fetches_event=NULL;
 static periodic_event_item_t *check_dns_honesty_event=NULL;
@@ -1484,24 +1437,7 @@ static periodic_event_item_t *prune_old_routers_event=NULL;
 void
 reset_all_main_loop_timers(void)
 {
-  int i;
-  for (i = 0; periodic_events[i].name; ++i) {
-    periodic_event_reschedule(&periodic_events[i]);
-  }
-}
-
-/** Return the member of periodic_events[] whose name is <b>name</b>.
- * Return NULL if no such event is found.
- */
-static periodic_event_item_t *
-find_periodic_event(const char *name)
-{
-  int i;
-  for (i = 0; periodic_events[i].name; ++i) {
-    if (strcmp(name, periodic_events[i].name) == 0)
-      return &periodic_events[i];
-  }
-  return NULL;
+  periodic_events_reset_all();
 }
 
 /** Return a bitmask of the roles this tor instance is configured for using
@@ -1564,9 +1500,9 @@ initialize_periodic_events_cb(evutil_socket_t fd, short events, void *data)
   rescan_periodic_events(get_options());
 }
 
-/** Set up all the members of periodic_events[], and configure them all to be
- * launched from a callback. */
-STATIC void
+/** Set up all the members of mainloop_periodic_events[], and configure them
+ * all to be launched from a callback. */
+void
 initialize_periodic_events(void)
 {
   if (periodic_events_initialized)
@@ -1574,37 +1510,31 @@ initialize_periodic_events(void)
 
   periodic_events_initialized = 1;
 
-  /* Set up all periodic events. We'll launch them by roles. */
-  int i;
-  for (i = 0; periodic_events[i].name; ++i) {
-    periodic_event_setup(&periodic_events[i]);
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_events_register(&mainloop_periodic_events[i]);
   }
 
+  /* Set up all periodic events. We'll launch them by roles. */
+
 #define NAMED_CALLBACK(name) \
-  STMT_BEGIN name ## _event = find_periodic_event( #name ); STMT_END
+  STMT_BEGIN name ## _event = periodic_events_find( #name ); STMT_END
 
-  NAMED_CALLBACK(check_descriptor);
   NAMED_CALLBACK(prune_old_routers);
-  NAMED_CALLBACK(dirvote);
   NAMED_CALLBACK(fetch_networkstatus);
   NAMED_CALLBACK(launch_descriptor_fetches);
   NAMED_CALLBACK(check_dns_honesty);
   NAMED_CALLBACK(save_state);
-
-  struct timeval one_second = { 1, 0 };
-  initialize_periodic_events_event = tor_evtimer_new(
-                  tor_libevent_get_base(),
-                  initialize_periodic_events_cb, NULL);
-  event_add(initialize_periodic_events_event, &one_second);
 }
 
 STATIC void
 teardown_periodic_events(void)
 {
-  int i;
-  for (i = 0; periodic_events[i].name; ++i) {
-    periodic_event_destroy(&periodic_events[i]);
-  }
+  periodic_events_disconnect_all();
+  fetch_networkstatus_event = NULL;
+  launch_descriptor_fetches_event = NULL;
+  check_dns_honesty_event = NULL;
+  save_state_event = NULL;
+  prune_old_routers_event = NULL;
   periodic_events_initialized = 0;
 }
 
@@ -1639,40 +1569,7 @@ rescan_periodic_events(const or_options_t *options)
 {
   tor_assert(options);
 
-  /* Avoid scanning the event list if we haven't initialized it yet. This is
-   * particularly useful for unit tests in order to avoid initializing main
-   * loop events everytime. */
-  if (!periodic_events_initialized) {
-    return;
-  }
-
-  int roles = get_my_roles(options);
-
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
-
-    int enable = !!(item->roles & roles);
-
-    /* Handle the event flags. */
-    if (net_is_disabled() &&
-        (item->flags & PERIODIC_EVENT_FLAG_NEED_NET)) {
-      enable = 0;
-    }
-
-    /* Enable the event if needed. It is safe to enable an event that was
-     * already enabled. Same goes for disabling it. */
-    if (enable) {
-      log_debug(LD_GENERAL, "Launching periodic event %s", item->name);
-      periodic_event_enable(item);
-    } else {
-      log_debug(LD_GENERAL, "Disabling periodic event %s", item->name);
-      if (item->flags & PERIODIC_EVENT_FLAG_RUN_ON_DISABLE) {
-        periodic_event_schedule_and_disable(item);
-      } else {
-        periodic_event_disable(item);
-      }
-    }
-  }
+  periodic_events_rescan_by_roles(get_my_roles(options), net_is_disabled());
 }
 
 /* We just got new options globally set, see if we need to enabled or disable
@@ -1680,26 +1577,7 @@ rescan_periodic_events(const or_options_t *options)
 void
 periodic_events_on_new_options(const or_options_t *options)
 {
-  /* Only if we've already initialized the events, rescan the list which will
-   * enable or disable events depending on our roles. This will be called at
-   * bootup and we don't want this function to initialize the events because
-   * they aren't set up at this stage. */
-  if (periodic_events_initialized) {
-    rescan_periodic_events(options);
-  }
-}
-
-/**
- * Update our schedule so that we'll check whether we need to update our
- * descriptor immediately, rather than after up to CHECK_DESCRIPTOR_INTERVAL
- * seconds.
- */
-void
-reschedule_descriptor_update_check(void)
-{
-  if (check_descriptor_event) {
-    periodic_event_reschedule(check_descriptor_event);
-  }
+  rescan_periodic_events(options);
 }
 
 /**
@@ -1769,29 +1647,6 @@ mainloop_schedule_shutdown(int delay_sec)
   mainloop_event_schedule(scheduled_shutdown_ev, &delay_tv);
 }
 
-#define LONGEST_TIMER_PERIOD (30 * 86400)
-/** Helper: Return the number of seconds between <b>now</b> and <b>next</b>,
- * clipped to the range [1 second, LONGEST_TIMER_PERIOD]. */
-static inline int
-safe_timer_diff(time_t now, time_t next)
-{
-  if (next > now) {
-    /* There were no computers at signed TIME_MIN (1902 on 32-bit systems),
-     * and nothing that could run Tor. It's a bug if 'next' is around then.
-     * On 64-bit systems with signed TIME_MIN, TIME_MIN is before the Big
-     * Bang. We cannot extrapolate past a singularity, but there was probably
-     * nothing that could run Tor then, either.
-     **/
-    tor_assert(next > TIME_MIN + LONGEST_TIMER_PERIOD);
-
-    if (next - LONGEST_TIMER_PERIOD > now)
-      return LONGEST_TIMER_PERIOD;
-    return (int)(next - now);
-  } else {
-    return 1;
-  }
-}
-
 /** Perform regular maintenance tasks.  This function gets run once per
  * second.
  */
@@ -1867,77 +1722,6 @@ second_elapsed_callback(time_t now, const or_options_t *options)
   return 1;
 }
 
-/* Periodic callback: rotate the onion keys after the period defined by the
- * "onion-key-rotation-days" consensus parameter, shut down and restart all
- * cpuworkers, and update our descriptor if necessary.
- */
-static int
-rotate_onion_key_callback(time_t now, const or_options_t *options)
-{
-  if (server_mode(options)) {
-    int onion_key_lifetime = get_onion_key_lifetime();
-    time_t rotation_time = get_onion_key_set_at()+onion_key_lifetime;
-    if (rotation_time > now) {
-      return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
-    }
-
-    log_info(LD_GENERAL,"Rotating onion key.");
-    rotate_onion_key();
-    cpuworkers_rotate_keyinfo();
-    if (router_rebuild_descriptor(1)<0) {
-      log_info(LD_CONFIG, "Couldn't rebuild router descriptor");
-    }
-    if (advertised_server_mode() && !net_is_disabled())
-      router_upload_dir_desc_to_dirservers(0);
-    return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
-  }
-  return PERIODIC_EVENT_NO_UPDATE;
-}
-
-/* Period callback: Check if our old onion keys are still valid after the
- * period of time defined by the consensus parameter
- * "onion-key-grace-period-days", otherwise expire them by setting them to
- * NULL.
- */
-static int
-check_onion_keys_expiry_time_callback(time_t now, const or_options_t *options)
-{
-  if (server_mode(options)) {
-    int onion_key_grace_period = get_onion_key_grace_period();
-    time_t expiry_time = get_onion_key_set_at()+onion_key_grace_period;
-    if (expiry_time > now) {
-      return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
-    }
-
-    log_info(LD_GENERAL, "Expiring old onion keys.");
-    expire_old_onion_keys();
-    cpuworkers_rotate_keyinfo();
-    return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
-  }
-
-  return PERIODIC_EVENT_NO_UPDATE;
-}
-
-/* Periodic callback: Every 30 seconds, check whether it's time to make new
- * Ed25519 subkeys.
- */
-static int
-check_ed_keys_callback(time_t now, const or_options_t *options)
-{
-  if (server_mode(options)) {
-    if (should_make_new_ed_keys(options, now)) {
-      int new_signing_key = load_ed_keys(options, now);
-      if (new_signing_key < 0 ||
-          generate_ed_link_cert(options, now, new_signing_key > 0)) {
-        log_err(LD_OR, "Unable to update Ed25519 keys!  Exiting.");
-        tor_shutdown_event_loop_and_exit(1);
-      }
-    }
-    return 30;
-  }
-  return PERIODIC_EVENT_NO_UPDATE;
-}
-
 /**
  * Periodic callback: Every {LAZY,GREEDY}_DESCRIPTOR_RETRY_INTERVAL,
  * see about fetching descriptors, microdescriptors, and extrainfo
@@ -2061,102 +1845,6 @@ check_network_participation_callback(time_t now, const or_options_t *options)
 }
 
 /**
- * Periodic callback: if we're an authority, make sure we test
- * the routers on the network for reachability.
- */
-static int
-launch_reachability_tests_callback(time_t now, const or_options_t *options)
-{
-  if (authdir_mode_tests_reachability(options) &&
-      !net_is_disabled()) {
-    /* try to determine reachability of the other Tor relays */
-    dirserv_test_reachability(now);
-  }
-  return REACHABILITY_TEST_INTERVAL;
-}
-
-/**
- * Periodic callback: if we're an authority, discount the stability
- * information (and other rephist information) that's older.
- */
-static int
-downrate_stability_callback(time_t now, const or_options_t *options)
-{
-  (void)options;
-  /* 1d. Periodically, we discount older stability information so that new
-   * stability info counts more, and save the stability information to disk as
-   * appropriate. */
-  time_t next = rep_hist_downrate_old_runs(now);
-  return safe_timer_diff(now, next);
-}
-
-/**
- * Periodic callback: if we're an authority, record our measured stability
- * information from rephist in an mtbf file.
- */
-static int
-save_stability_callback(time_t now, const or_options_t *options)
-{
-  if (authdir_mode_tests_reachability(options)) {
-    if (rep_hist_record_mtbf_data(now, 1)<0) {
-      log_warn(LD_GENERAL, "Couldn't store mtbf data.");
-    }
-  }
-#define SAVE_STABILITY_INTERVAL (30*60)
-  return SAVE_STABILITY_INTERVAL;
-}
-
-/**
- * Periodic callback: if we're an authority, check on our authority
- * certificate (the one that authenticates our authority signing key).
- */
-static int
-check_authority_cert_callback(time_t now, const or_options_t *options)
-{
-  (void)now;
-  (void)options;
-  /* 1e. Periodically, if we're a v3 authority, we check whether our cert is
-   * close to expiring and warn the admin if it is. */
-  v3_authority_check_key_expiry();
-#define CHECK_V3_CERTIFICATE_INTERVAL (5*60)
-  return CHECK_V3_CERTIFICATE_INTERVAL;
-}
-
-/**
- * Scheduled callback: Run directory-authority voting functionality.
- *
- * The schedule is a bit complicated here, so dirvote_act() manages the
- * schedule itself.
- **/
-static int
-dirvote_callback(time_t now, const or_options_t *options)
-{
-  if (!authdir_mode_v3(options)) {
-    tor_assert_nonfatal_unreached();
-    return 3600;
-  }
-
-  time_t next = dirvote_act(options, now);
-  if (BUG(next == TIME_MAX)) {
-    /* This shouldn't be returned unless we called dirvote_act() without
-     * being an authority.  If it happens, maybe our configuration will
-     * fix itself in an hour or so? */
-    return 3600;
-  }
-  return safe_timer_diff(now, next);
-}
-
-/** Reschedule the directory-authority voting event.  Run this whenever the
- * schedule has changed. */
-void
-reschedule_dirvote(const or_options_t *options)
-{
-  if (periodic_events_initialized && authdir_mode_v3(options)) {
-    periodic_event_reschedule(dirvote_event);
-  }
-}
-
-/**
  * Periodic callback: If our consensus is too old, recalculate whether
  * we can actually use it.
  */
@@ -2254,17 +1942,6 @@ write_stats_file_callback(time_t now, const or_options_t *options)
   return safe_timer_diff(now, next_time_to_write_stats_files);
 }
 
-#define CHANNEL_CHECK_INTERVAL (60*60)
-static int
-check_canonical_channels_callback(time_t now, const or_options_t *options)
-{
-  (void)now;
-  if (public_server_mode(options))
-    channel_check_for_duplicates();
-
-  return CHANNEL_CHECK_INTERVAL;
-}
-
 static int
 reset_padding_counts_callback(time_t now, const or_options_t *options)
 {
@@ -2339,19 +2016,6 @@ rend_cache_failure_clean_callback(time_t now, const or_options_t *options)
 }
 
 /**
- * Periodic callback: If we're a server and initializing dns failed, retry.
- */
-static int
-retry_dns_callback(time_t now, const or_options_t *options)
-{
-  (void)now;
-#define RETRY_DNS_INTERVAL (10*60)
-  if (server_mode(options) && has_dns_init_failed())
-    dns_init();
-  return RETRY_DNS_INTERVAL;
-}
-
-/**
  * Periodic callback: prune routerlist of old information about Tor network.
  */
 static int
@@ -2372,71 +2036,6 @@ prune_old_routers_callback(time_t now, const or_options_t *options)
   return ROUTERLIST_PRUNING_INTERVAL;
 }
 
-/** Periodic callback: consider rebuilding or and re-uploading our descriptor
- * (if we've passed our internal checks). */
-static int
-check_descriptor_callback(time_t now, const or_options_t *options)
-{
-/** How often do we check whether part of our router info has changed in a
- * way that would require an upload? That includes checking whether our IP
- * address has changed. */
-#define CHECK_DESCRIPTOR_INTERVAL (60)
-
-  (void)options;
-
-  /* 2b. Once per minute, regenerate and upload the descriptor if the old
-   * one is inaccurate. */
-  if (!net_is_disabled()) {
-    check_descriptor_bandwidth_changed(now);
-    check_descriptor_ipaddress_changed(now);
-    mark_my_descriptor_dirty_if_too_old(now);
-    consider_publishable_server(0);
-  }
-
-  return CHECK_DESCRIPTOR_INTERVAL;
-}
-
-/**
- * Periodic callback: check whether we're reachable (as a relay), and
- * whether our bandwidth has changed enough that we need to
- * publish a new descriptor.
- */
-static int
-check_for_reachability_bw_callback(time_t now, const or_options_t *options)
-{
-  /* XXXX This whole thing was stuck in the middle of what is now
-   * XXXX check_descriptor_callback.  I'm not sure it's right. */
-
-  static int dirport_reachability_count = 0;
-  /* also, check religiously for reachability, if it's within the first
-   * 20 minutes of our uptime. */
-  if (server_mode(options) &&
-      (have_completed_a_circuit() || !any_predicted_circuits(now)) &&
-      !net_is_disabled()) {
-    if (get_uptime() < TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT) {
-      router_do_reachability_checks(1, dirport_reachability_count==0);
-      if (++dirport_reachability_count > 5)
-        dirport_reachability_count = 0;
-      return 1;
-    } else {
-      /* If we haven't checked for 12 hours and our bandwidth estimate is
-       * low, do another bandwidth test. This is especially important for
-       * bridges, since they might go long periods without much use. */
-      const routerinfo_t *me = router_get_my_routerinfo();
-      static int first_time = 1;
-      if (!first_time && me &&
-          me->bandwidthcapacity < me->bandwidthrate &&
-          me->bandwidthcapacity < 51200) {
-        reset_bandwidth_test();
-      }
-      first_time = 0;
-#define BANDWIDTH_RECHECK_INTERVAL (12*60*60)
-      return BANDWIDTH_RECHECK_INTERVAL;
-    }
-  }
-  return CHECK_DESCRIPTOR_INTERVAL;
-}
-
 /**
  * Periodic event: once a minute, (or every second if TestingTorNetwork, or
  * during client bootstrap), check whether we want to download any
@@ -2479,109 +2078,6 @@ retry_listeners_callback(time_t now, const or_options_t *options)
   return PERIODIC_EVENT_NO_UPDATE;
 }
 
-/**
- * Periodic callback: as a server, see if we have any old unused circuits
- * that should be expired */
-static int
-expire_old_ciruits_serverside_callback(time_t now, const or_options_t *options)
-{
-  (void)options;
-  /* every 11 seconds, so not usually the same second as other such events */
-  circuit_expire_old_circuits_serverside(now);
-  return 11;
-}
-
-/**
- * Callback: Send warnings if Tor doesn't find its ports reachable.
- */
-static int
-reachability_warnings_callback(time_t now, const or_options_t *options)
-{
-  (void) now;
-
-  if (get_uptime() < TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT) {
-    return (int)(TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT - get_uptime());
-  }
-
-  if (server_mode(options) &&
-      !net_is_disabled() &&
-      have_completed_a_circuit()) {
-    /* every 20 minutes, check and complain if necessary */
-    const routerinfo_t *me = router_get_my_routerinfo();
-    if (me && !check_whether_orport_reachable(options)) {
-      char *address = tor_dup_ip(me->addr);
-      log_warn(LD_CONFIG,"Your server (%s:%d) has not managed to confirm that "
-               "its ORPort is reachable. Relays do not publish descriptors "
-               "until their ORPort and DirPort are reachable. Please check "
-               "your firewalls, ports, address, /etc/hosts file, etc.",
-               address, me->or_port);
-      control_event_server_status(LOG_WARN,
-                                  "REACHABILITY_FAILED ORADDRESS=%s:%d",
-                                  address, me->or_port);
-      tor_free(address);
-    }
-
-    if (me && !check_whether_dirport_reachable(options)) {
-      char *address = tor_dup_ip(me->addr);
-      log_warn(LD_CONFIG,
-               "Your server (%s:%d) has not managed to confirm that its "
-               "DirPort is reachable. Relays do not publish descriptors "
-               "until their ORPort and DirPort are reachable. Please check "
-               "your firewalls, ports, address, /etc/hosts file, etc.",
-               address, me->dir_port);
-      control_event_server_status(LOG_WARN,
-                                  "REACHABILITY_FAILED DIRADDRESS=%s:%d",
-                                  address, me->dir_port);
-      tor_free(address);
-    }
-  }
-
-  return TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT;
-}
-
-static int dns_honesty_first_time = 1;
-
-/**
- * Periodic event: if we're an exit, see if our DNS server is telling us
- * obvious lies.
- */
-static int
-check_dns_honesty_callback(time_t now, const or_options_t *options)
-{
-  (void)now;
-  /* 9. and if we're an exit node, check whether our DNS is telling stories
-   * to us. */
-  if (net_is_disabled() ||
-      ! public_server_mode(options) ||
-      router_my_exit_policy_is_reject_star())
-    return PERIODIC_EVENT_NO_UPDATE;
-
-  if (dns_honesty_first_time) {
-    /* Don't launch right when we start */
-    dns_honesty_first_time = 0;
-    return crypto_rand_int_range(60, 180);
-  }
-
-  dns_launch_correctness_checks();
-  return 12*3600 + crypto_rand_int(12*3600);
-}
-
-/**
- * Periodic callback: if we're the bridge authority, write a networkstatus
- * file to disk.
- */
-static int
-write_bridge_ns_callback(time_t now, const or_options_t *options)
-{
-  /* 10. write bridge networkstatus file to disk */
-  if (options->BridgeAuthoritativeDir) {
-    networkstatus_dump_bridge_status_to_file(now);
-#define BRIDGE_STATUSFILE_INTERVAL (30*60)
-     return BRIDGE_STATUSFILE_INTERVAL;
-  }
-  return PERIODIC_EVENT_NO_UPDATE;
-}
-
 static int heartbeat_callback_first_time = 1;
 
 /**
@@ -2797,8 +2293,7 @@ dns_servers_relaunch_checks(void)
 {
   if (server_mode(get_options())) {
     dns_reset_correctness_checks();
-    if (periodic_events_initialized) {
-      tor_assert(check_dns_honesty_event);
+    if (check_dns_honesty_event) {
       periodic_event_reschedule(check_dns_honesty_event);
     }
   }
@@ -2808,8 +2303,6 @@ dns_servers_relaunch_checks(void)
 void
 initialize_mainloop_events(void)
 {
-  initialize_periodic_events();
-
   if (!schedule_active_linked_connections_event) {
     schedule_active_linked_connections_event =
       mainloop_event_postloop_new(schedule_active_linked_connections_cb, NULL);
@@ -2827,9 +2320,17 @@ do_main_loop(void)
   /* initialize the periodic events first, so that code that depends on the
    * events being present does not assert.
    */
-  initialize_periodic_events();
+  tor_assert(periodic_events_initialized);
   initialize_mainloop_events();
 
+  periodic_events_connect_all();
+
+  struct timeval one_second = { 1, 0 };
+  initialize_periodic_events_event = tor_evtimer_new(
+                  tor_libevent_get_base(),
+                  initialize_periodic_events_cb, NULL);
+  event_add(initialize_periodic_events_event, &one_second);
+
 #ifdef HAVE_SYSTEMD_209
   uint64_t watchdog_delay;
   /* set up systemd watchdog notification. */
@@ -2874,7 +2375,7 @@ do_main_loop(void)
       event_add(tor_shutdown_event_loop_for_restart_event, &restart_after);
     }
   }
-#endif
+#endif /* defined(ENABLE_RESTART_DEBUGGING) */
 
   return run_main_loop_until_done();
 }
@@ -3042,7 +2543,6 @@ tor_mainloop_free_all(void)
   can_complete_circuits = 0;
   quiet_level = 0;
   should_init_bridge_stats = 1;
-  dns_honesty_first_time = 1;
   heartbeat_callback_first_time = 1;
   current_second = 0;
   memset(¤t_second_last_changed, 0,
diff --git a/src/core/mainloop/mainloop.h b/src/core/mainloop/mainloop.h
index 6ed93fa90..caef736c1 100644
--- a/src/core/mainloop/mainloop.h
+++ b/src/core/mainloop/mainloop.h
@@ -59,10 +59,8 @@ void directory_info_has_arrived(time_t now, int from_cache, int suppress_logs);
 void ip_address_changed(int at_interface);
 void dns_servers_relaunch_checks(void);
 void reset_all_main_loop_timers(void);
-void reschedule_descriptor_update_check(void);
 void reschedule_directory_downloads(void);
 void reschedule_or_state_save(void);
-void reschedule_dirvote(const or_options_t *options);
 void mainloop_schedule_postloop_cleanup(void);
 void rescan_periodic_events(const or_options_t *options);
 MOCK_DECL(void, schedule_rescan_periodic_events,(void));
@@ -90,6 +88,7 @@ void mainloop_schedule_shutdown(int delay_sec);
 
 void tor_init_connection_lists(void);
 void initialize_mainloop_events(void);
+void initialize_periodic_events(void);
 void tor_mainloop_free_all(void);
 
 struct token_bucket_rw_t;
@@ -102,7 +101,6 @@ extern struct token_bucket_rw_t global_relayed_bucket;
 #ifdef MAINLOOP_PRIVATE
 STATIC int run_main_loop_until_done(void);
 STATIC void close_closeable_connections(void);
-STATIC void initialize_periodic_events(void);
 STATIC void teardown_periodic_events(void);
 STATIC int get_my_roles(const or_options_t *);
 STATIC int check_network_participation_callback(time_t now,
@@ -113,8 +111,8 @@ extern smartlist_t *connection_array;
 
 /* We need the periodic_event_item_t definition. */
 #include "core/mainloop/periodic.h"
-extern periodic_event_item_t periodic_events[];
-#endif
-#endif /* defined(MAIN_PRIVATE) */
+extern periodic_event_item_t mainloop_periodic_events[];
+#endif /* defined(TOR_UNIT_TESTS) */
+#endif /* defined(MAINLOOP_PRIVATE) */
 
-#endif
+#endif /* !defined(TOR_MAINLOOP_H) */
diff --git a/src/core/mainloop/mainloop_pubsub.c b/src/core/mainloop/mainloop_pubsub.c
new file mode 100644
index 000000000..53275d811
--- /dev/null
+++ b/src/core/mainloop/mainloop_pubsub.c
@@ -0,0 +1,170 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "orconfig.h"
+
+#include "core/or/or.h"
+#include "core/mainloop/mainloop.h"
+#include "core/mainloop/mainloop_pubsub.h"
+
+#include "lib/container/smartlist.h"
+#include "lib/dispatch/dispatch.h"
+#include "lib/dispatch/dispatch_naming.h"
+#include "lib/evloop/compat_libevent.h"
+#include "lib/pubsub/pubsub.h"
+#include "lib/pubsub/pubsub_build.h"
+
+/**
+ * Dispatcher to use for delivering messages.
+ **/
+static dispatch_t *the_dispatcher = NULL;
+static pubsub_items_t *the_pubsub_items = NULL;
+/**
+ * A list of mainloop_event_t, indexed by channel ID, to flush the messages
+ * on a channel.
+ **/
+static smartlist_t *alert_events = NULL;
+
+/**
+ * Mainloop event callback: flush all the messages in a channel.
+ *
+ * The channel is encoded as a pointer, and passed via arg.
+ **/
+static void
+flush_channel_event(mainloop_event_t *ev, void *arg)
+{
+  (void)ev;
+  if (!the_dispatcher)
+    return;
+
+  channel_id_t chan = (channel_id_t)(uintptr_t)(arg);
+  dispatch_flush(the_dispatcher, chan, INT_MAX);
+}
+
+/**
+ * Construct our global pubsub object from <b>builder</b>. Return 0 on
+ * success, -1 on failure. */
+int
+tor_mainloop_connect_pubsub(struct pubsub_builder_t *builder)
+{
+  int rv = -1;
+  tor_mainloop_disconnect_pubsub();
+
+  the_dispatcher = pubsub_builder_finalize(builder, &the_pubsub_items);
+  if (! the_dispatcher)
+    goto err;
+
+  rv = 0;
+  goto done;
+ err:
+  tor_mainloop_disconnect_pubsub();
+ done:
+  return rv;
+}
+
+/**
+ * Install libevent events for all of the pubsub channels.
+ *
+ * Invoke this after tor_mainloop_connect_pubsub, and after libevent has been
+ * initialized.
+ */
+void
+tor_mainloop_connect_pubsub_events(void)
+{
+  tor_assert(the_dispatcher);
+  tor_assert(! alert_events);
+
+  const size_t num_channels = get_num_channel_ids();
+  alert_events = smartlist_new();
+  for (size_t i = 0; i < num_channels; ++i) {
+    smartlist_add(alert_events,
+                  mainloop_event_postloop_new(flush_channel_event,
+                                              (void*)(uintptr_t)(i)));
+  }
+}
+
+/**
+ * Dispatch alertfn callback: do nothing. Implements DELIV_NEVER.
+ **/
+static void
+alertfn_never(dispatch_t *d, channel_id_t chan, void *arg)
+{
+  (void)d;
+  (void)chan;
+  (void)arg;
+}
+
+/**
+ * Dispatch alertfn callback: activate a mainloop event. Implements
+ * DELIV_PROMPT.
+ **/
+static void
+alertfn_prompt(dispatch_t *d, channel_id_t chan, void *arg)
+{
+  (void)d;
+  (void)chan;
+  mainloop_event_t *event = arg;
+  mainloop_event_activate(event);
+}
+
+/**
+ * Dispatch alertfn callback: flush all messages right now. Implements
+ * DELIV_IMMEDIATE.
+ **/
+static void
+alertfn_immediate(dispatch_t *d, channel_id_t chan, void *arg)
+{
+  (void) arg;
+  dispatch_flush(d, chan, INT_MAX);
+}
+
+/**
+ * Set the strategy to be used for delivering messages on the named channel.
+ *
+ * This function needs to be called once globally for each channel, to
+ * set up how messages are delivered.
+ **/
+int
+tor_mainloop_set_delivery_strategy(const char *msg_channel_name,
+                                   deliv_strategy_t strategy)
+{
+  channel_id_t chan = get_channel_id(msg_channel_name);
+  if (BUG(chan == ERROR_ID) ||
+      BUG(chan >= smartlist_len(alert_events)))
+    return -1;
+
+  switch (strategy) {
+    case DELIV_NEVER:
+      dispatch_set_alert_fn(the_dispatcher, chan, alertfn_never, NULL);
+      break;
+    case DELIV_PROMPT:
+      dispatch_set_alert_fn(the_dispatcher, chan, alertfn_prompt,
+                            smartlist_get(alert_events, chan));
+      break;
+    case DELIV_IMMEDIATE:
+      dispatch_set_alert_fn(the_dispatcher, chan, alertfn_immediate, NULL);
+      break;
+  }
+  return 0;
+}
+
+/**
+ * Remove all pubsub dispatchers and events from the mainloop.
+ **/
+void
+tor_mainloop_disconnect_pubsub(void)
+{
+  if (the_pubsub_items) {
+    pubsub_items_clear_bindings(the_pubsub_items);
+    pubsub_items_free(the_pubsub_items);
+  }
+  if (alert_events) {
+    SMARTLIST_FOREACH(alert_events, mainloop_event_t *, ev,
+                      mainloop_event_free(ev));
+    smartlist_free(alert_events);
+  }
+  dispatch_free(the_dispatcher);
+}
diff --git a/src/core/mainloop/mainloop_pubsub.h b/src/core/mainloop/mainloop_pubsub.h
new file mode 100644
index 000000000..365a3dd56
--- /dev/null
+++ b/src/core/mainloop/mainloop_pubsub.h
@@ -0,0 +1,24 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_MAINLOOP_PUBSUB_H
+#define TOR_MAINLOOP_PUBSUB_H
+
+struct pubsub_builder_t;
+
+typedef enum {
+   DELIV_NEVER=0,
+   DELIV_PROMPT,
+   DELIV_IMMEDIATE,
+} deliv_strategy_t;
+
+int tor_mainloop_connect_pubsub(struct pubsub_builder_t *builder);
+void tor_mainloop_connect_pubsub_events(void);
+int tor_mainloop_set_delivery_strategy(const char *msg_channel_name,
+                                        deliv_strategy_t strategy);
+void tor_mainloop_disconnect_pubsub(void);
+
+#endif /* !defined(TOR_MAINLOOP_PUBSUB_H) */
diff --git a/src/core/mainloop/mainloop_sys.c b/src/core/mainloop/mainloop_sys.c
new file mode 100644
index 000000000..fbd5a4032
--- /dev/null
+++ b/src/core/mainloop/mainloop_sys.c
@@ -0,0 +1,32 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "core/or/or.h"
+#include "core/mainloop/mainloop_sys.h"
+#include "core/mainloop/mainloop.h"
+
+#include "lib/subsys/subsys.h"
+
+static int
+subsys_mainloop_initialize(void)
+{
+  initialize_periodic_events();
+  return 0;
+}
+
+static void
+subsys_mainloop_shutdown(void)
+{
+  tor_mainloop_free_all();
+}
+
+const struct subsys_fns_t sys_mainloop = {
+  .name = "mainloop",
+  .supported = true,
+  .level = 5,
+  .initialize = subsys_mainloop_initialize,
+  .shutdown = subsys_mainloop_shutdown,
+};
diff --git a/src/core/mainloop/mainloop_sys.h b/src/core/mainloop/mainloop_sys.h
new file mode 100644
index 000000000..fa74fe5d4
--- /dev/null
+++ b/src/core/mainloop/mainloop_sys.h
@@ -0,0 +1,12 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef MAINLOOP_SYS_H
+#define MAINLOOP_SYS_H
+
+extern const struct subsys_fns_t sys_mainloop;
+
+#endif /* !defined(MAINLOOP_SYS_H) */
diff --git a/src/core/mainloop/netstatus.h b/src/core/mainloop/netstatus.h
index aba631e2f..e8469ff55 100644
--- a/src/core/mainloop/netstatus.h
+++ b/src/core/mainloop/netstatus.h
@@ -21,4 +21,4 @@ void netstatus_flush_to_state(or_state_t *state, time_t now);
 void netstatus_load_from_state(const or_state_t *state, time_t now);
 void netstatus_note_clock_jumped(time_t seconds_diff);
 
-#endif
+#endif /* !defined(TOR_NETSTATUS_H) */
diff --git a/src/core/mainloop/periodic.c b/src/core/mainloop/periodic.c
index c0363b15e..dbc4553a7 100644
--- a/src/core/mainloop/periodic.c
+++ b/src/core/mainloop/periodic.c
@@ -6,9 +6,22 @@
  *
  * \brief Generic backend for handling periodic events.
  *
- * The events in this module are used by main.c to track items that need
+ * The events in this module are used to track items that need
  * to fire once every N seconds, possibly picking a new interval each time
- * that they fire.  See periodic_events[] in main.c for examples.
+ * that they fire.  See periodic_events[] in mainloop.c for examples.
+ *
+ * This module manages a global list of periodic_event_item_t objects,
+ * each corresponding to a single event.  To register an event, pass it to
+ * periodic_events_register() when initializing your subsystem.
+ *
+ * Registering an event makes the periodic event subsystem know about it, but
+ * doesn't cause the event to get created immediately.  Before the event can
+ * be started, periodic_event_connect_all() must be called by mainloop.c to
+ * connect all the events to Libevent.
+ *
+ * We expect that periodic_event_item_t objects will be statically allocated;
+ * we set them up and tear them down here, but we don't take ownership of
+ * them.
  */
 
 #include "core/or/or.h"
@@ -24,6 +37,12 @@
  */
 static const int MAX_INTERVAL = 10 * 365 * 86400;
 
+/**
+ * Global list of periodic events that have been registered with
+ * <b>periodic_event_register</a>.
+ **/
+static smartlist_t *the_periodic_events = NULL;
+
 /** Set the event <b>event</b> to run in <b>next_interval</b> seconds from
  * now. */
 static void
@@ -87,15 +106,16 @@ periodic_event_dispatch(mainloop_event_t *ev, void *data)
 void
 periodic_event_reschedule(periodic_event_item_t *event)
 {
-  /* Don't reschedule a disabled event. */
-  if (periodic_event_is_enabled(event)) {
+  /* Don't reschedule a disabled or uninitialized event. */
+  if (event->ev && periodic_event_is_enabled(event)) {
     periodic_event_set_interval(event, 1);
   }
 }
 
-/** Initializes the libevent backend for a periodic event. */
+/** Connects a periodic event to the Libevent backend.  Does not launch the
+ * event immediately. */
 void
-periodic_event_setup(periodic_event_item_t *event)
+periodic_event_connect(periodic_event_item_t *event)
 {
   if (event->ev) { /* Already setup? This is a bug */
     log_err(LD_BUG, "Initial dispatch should only be done once.");
@@ -113,7 +133,7 @@ void
 periodic_event_launch(periodic_event_item_t *event)
 {
   if (! event->ev) { /* Not setup? This is a bug */
-    log_err(LD_BUG, "periodic_event_launch without periodic_event_setup");
+    log_err(LD_BUG, "periodic_event_launch without periodic_event_connect");
     tor_assert(0);
   }
   /* Event already enabled? This is a bug */
@@ -127,9 +147,9 @@ periodic_event_launch(periodic_event_item_t *event)
   periodic_event_dispatch(event->ev, event);
 }
 
-/** Release all storage associated with <b>event</b> */
-void
-periodic_event_destroy(periodic_event_item_t *event)
+/** Disconnect and unregister the periodic event in <b>event</b> */
+static void
+periodic_event_disconnect(periodic_event_item_t *event)
 {
   if (!event)
     return;
@@ -184,3 +204,161 @@ periodic_event_schedule_and_disable(periodic_event_item_t *event)
 
   mainloop_event_activate(event->ev);
 }
+
+/**
+ * Add <b>item</b> to the list of periodic events.
+ *
+ * Note that <b>item</b> should be statically allocated: we do not
+ * take ownership of it.
+ **/
+void
+periodic_events_register(periodic_event_item_t *item)
+{
+  if (!the_periodic_events)
+    the_periodic_events = smartlist_new();
+
+  if (BUG(smartlist_contains(the_periodic_events, item)))
+    return;
+
+  smartlist_add(the_periodic_events, item);
+}
+
+/**
+ * Make all registered periodic events connect to the libevent backend.
+ */
+void
+periodic_events_connect_all(void)
+{
+  if (! the_periodic_events)
+    return;
+
+  SMARTLIST_FOREACH_BEGIN(the_periodic_events, periodic_event_item_t *, item) {
+    if (item->ev)
+      continue;
+    periodic_event_connect(item);
+  } SMARTLIST_FOREACH_END(item);
+}
+
+/**
+ * Reset all the registered periodic events so we'll do all our actions again
+ * as if we just started up.
+ *
+ * Useful if our clock just moved back a long time from the future,
+ * so we don't wait until that future arrives again before acting.
+ */
+void
+periodic_events_reset_all(void)
+{
+  if (! the_periodic_events)
+    return;
+
+  SMARTLIST_FOREACH_BEGIN(the_periodic_events, periodic_event_item_t *, item) {
+    if (!item->ev)
+      continue;
+
+    periodic_event_reschedule(item);
+  } SMARTLIST_FOREACH_END(item);
+}
+
+/**
+ * Return the registered periodic event whose name is <b>name</b>.
+ * Return NULL if no such event is found.
+ */
+periodic_event_item_t *
+periodic_events_find(const char *name)
+{
+  if (! the_periodic_events)
+    return NULL;
+
+  SMARTLIST_FOREACH_BEGIN(the_periodic_events, periodic_event_item_t *, item) {
+    if (strcmp(name, item->name) == 0)
+      return item;
+  } SMARTLIST_FOREACH_END(item);
+  return NULL;
+}
+
+/**
+ * Start or stop registered periodic events, depending on our current set of
+ * roles.
+ *
+ * Invoked when our list of roles, or the net_disabled flag has changed.
+ **/
+void
+periodic_events_rescan_by_roles(int roles, bool net_disabled)
+{
+  if (! the_periodic_events)
+    return;
+
+  SMARTLIST_FOREACH_BEGIN(the_periodic_events, periodic_event_item_t *, item) {
+    if (!item->ev)
+      continue;
+
+    int enable = !!(item->roles & roles);
+
+    /* Handle the event flags. */
+    if (net_disabled &&
+        (item->flags & PERIODIC_EVENT_FLAG_NEED_NET)) {
+      enable = 0;
+    }
+
+    /* Enable the event if needed. It is safe to enable an event that was
+     * already enabled. Same goes for disabling it. */
+    if (enable) {
+      log_debug(LD_GENERAL, "Launching periodic event %s", item->name);
+      periodic_event_enable(item);
+    } else {
+      log_debug(LD_GENERAL, "Disabling periodic event %s", item->name);
+      if (item->flags & PERIODIC_EVENT_FLAG_RUN_ON_DISABLE) {
+        periodic_event_schedule_and_disable(item);
+      } else {
+        periodic_event_disable(item);
+      }
+    }
+  } SMARTLIST_FOREACH_END(item);
+}
+
+/**
+ * Invoked at shutdown: disconnect and unregister all periodic events.
+ *
+ * Does not free the periodic_event_item_t object themselves, because we do
+ * not own them.
+ */
+void
+periodic_events_disconnect_all(void)
+{
+  if (! the_periodic_events)
+    return;
+
+  SMARTLIST_FOREACH_BEGIN(the_periodic_events, periodic_event_item_t *, item) {
+    periodic_event_disconnect(item);
+  } SMARTLIST_FOREACH_END(item);
+
+  smartlist_free(the_periodic_events);
+}
+
+#define LONGEST_TIMER_PERIOD (30 * 86400)
+/** Helper: Return the number of seconds between <b>now</b> and <b>next</b>,
+ * clipped to the range [1 second, LONGEST_TIMER_PERIOD].
+ *
+ * We use this to answer the question, "how many seconds is it from now until
+ * next" in periodic timer callbacks.  Don't use it for other purposes
+ **/
+int
+safe_timer_diff(time_t now, time_t next)
+{
+  if (next > now) {
+    /* There were no computers at signed TIME_MIN (1902 on 32-bit systems),
+     * and nothing that could run Tor. It's a bug if 'next' is around then.
+     * On 64-bit systems with signed TIME_MIN, TIME_MIN is before the Big
+     * Bang. We cannot extrapolate past a singularity, but there was probably
+     * nothing that could run Tor then, either.
+     **/
+    tor_assert(next > TIME_MIN + LONGEST_TIMER_PERIOD);
+
+    if (next - LONGEST_TIMER_PERIOD > now)
+      return LONGEST_TIMER_PERIOD;
+    return (int)(next - now);
+  } else {
+    return 1;
+  }
+}
diff --git a/src/core/mainloop/periodic.h b/src/core/mainloop/periodic.h
index 344fc9ad2..a9aa46196 100644
--- a/src/core/mainloop/periodic.h
+++ b/src/core/mainloop/periodic.h
@@ -83,11 +83,20 @@ periodic_event_is_enabled(const periodic_event_item_t *item)
 }
 
 void periodic_event_launch(periodic_event_item_t *event);
-void periodic_event_setup(periodic_event_item_t *event);
-void periodic_event_destroy(periodic_event_item_t *event);
+void periodic_event_connect(periodic_event_item_t *event);
+//void periodic_event_disconnect(periodic_event_item_t *event);
 void periodic_event_reschedule(periodic_event_item_t *event);
 void periodic_event_enable(periodic_event_item_t *event);
 void periodic_event_disable(periodic_event_item_t *event);
 void periodic_event_schedule_and_disable(periodic_event_item_t *event);
 
+void periodic_events_register(periodic_event_item_t *item);
+void periodic_events_connect_all(void);
+void periodic_events_reset_all(void);
+periodic_event_item_t *periodic_events_find(const char *name);
+void periodic_events_rescan_by_roles(int roles, bool net_disabled);
+void periodic_events_disconnect_all(void);
+
+int safe_timer_diff(time_t now, time_t next);
+
 #endif /* !defined(TOR_PERIODIC_H) */
diff --git a/src/core/or/addr_policy_st.h b/src/core/or/addr_policy_st.h
index a75f1a731..11442d29b 100644
--- a/src/core/or/addr_policy_st.h
+++ b/src/core/or/addr_policy_st.h
@@ -43,4 +43,4 @@ struct addr_policy_t {
   uint16_t prt_max; /**< Highest port number to accept/reject. */
 };
 
-#endif
+#endif /* !defined(TOR_ADDR_POLICY_ST_H) */
diff --git a/src/core/or/address_set.h b/src/core/or/address_set.h
index 7a9e71628..95608a9a5 100644
--- a/src/core/or/address_set.h
+++ b/src/core/or/address_set.h
@@ -28,4 +28,4 @@ void address_set_add_ipv4h(address_set_t *set, uint32_t addr);
 int address_set_probably_contains(const address_set_t *set,
                                   const struct tor_addr_t *addr);
 
-#endif
+#endif /* !defined(TOR_ADDRESS_SET_H) */
diff --git a/src/core/or/cell_queue_st.h b/src/core/or/cell_queue_st.h
index 130b95a01..7ba339b96 100644
--- a/src/core/or/cell_queue_st.h
+++ b/src/core/or/cell_queue_st.h
@@ -26,4 +26,4 @@ struct cell_queue_t {
   int n; /**< The number of cells in the queue. */
 };
 
-#endif
+#endif /* !defined(PACKED_CELL_ST_H) */
diff --git a/src/core/or/cell_st.h b/src/core/or/cell_st.h
index 7ab7eceb5..c4eec4f4b 100644
--- a/src/core/or/cell_st.h
+++ b/src/core/or/cell_st.h
@@ -16,5 +16,5 @@ struct cell_t {
   uint8_t payload[CELL_PAYLOAD_SIZE]; /**< Cell body. */
 };
 
-#endif
+#endif /* !defined(CELL_ST_H) */
 
diff --git a/src/core/or/channel.c b/src/core/or/channel.c
index fd7bf6278..0e190809b 100644
--- a/src/core/or/channel.c
+++ b/src/core/or/channel.c
@@ -1418,6 +1418,7 @@ write_packed_cell(channel_t *chan, packed_cell_t *cell)
 {
   int ret = -1;
   size_t cell_bytes;
+  uint8_t command = packed_cell_get_command(cell, chan->wide_circ_ids);
 
   tor_assert(chan);
   tor_assert(cell);
@@ -1452,6 +1453,16 @@ write_packed_cell(channel_t *chan, packed_cell_t *cell)
   /* Successfully sent the cell. */
   ret = 0;
 
+  /* Update padding statistics for the packed codepath.. */
+  rep_hist_padding_count_write(PADDING_TYPE_TOTAL);
+  if (command == CELL_PADDING)
+    rep_hist_padding_count_write(PADDING_TYPE_CELL);
+  if (chan->padding_enabled) {
+    rep_hist_padding_count_write(PADDING_TYPE_ENABLED_TOTAL);
+    if (command == CELL_PADDING)
+      rep_hist_padding_count_write(PADDING_TYPE_ENABLED_CELL);
+  }
+
  done:
   return ret;
 }
diff --git a/src/core/or/channeltls.c b/src/core/or/channeltls.c
index f552b2077..2a6edc951 100644
--- a/src/core/or/channeltls.c
+++ b/src/core/or/channeltls.c
@@ -1094,13 +1094,13 @@ channel_tls_handle_cell(cell_t *cell, or_connection_t *conn)
   entry_guards_note_internet_connectivity(get_guard_selection_info());
   rep_hist_padding_count_read(PADDING_TYPE_TOTAL);
 
-  if (TLS_CHAN_TO_BASE(chan)->currently_padding)
+  if (TLS_CHAN_TO_BASE(chan)->padding_enabled)
     rep_hist_padding_count_read(PADDING_TYPE_ENABLED_TOTAL);
 
   switch (cell->command) {
     case CELL_PADDING:
       rep_hist_padding_count_read(PADDING_TYPE_CELL);
-      if (TLS_CHAN_TO_BASE(chan)->currently_padding)
+      if (TLS_CHAN_TO_BASE(chan)->padding_enabled)
         rep_hist_padding_count_read(PADDING_TYPE_ENABLED_CELL);
       ++stats_n_padding_cells_processed;
       /* do nothing */
@@ -1664,7 +1664,19 @@ tor_addr_from_netinfo_addr(tor_addr_t *tor_addr,
 }
 
 /**
- * Process a 'netinfo' cell.
+ * Helper: compute the absolute value of a time_t.
+ *
+ * (we need this because labs() doesn't always work for time_t, since
+ * long can be shorter than time_t.)
+ */
+static inline time_t
+time_abs(time_t val)
+{
+  return (val < 0) ? -val : val;
+}
+
+/**
+ * Process a 'netinfo' cell
  *
  * This function is called to handle an incoming NETINFO cell; read and act
  * on its contents, and set the connection state to "open".
@@ -1679,7 +1691,7 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan)
   time_t now = time(NULL);
   const routerinfo_t *me = router_get_my_routerinfo();
 
-  long apparent_skew = 0;
+  time_t apparent_skew = 0;
   tor_addr_t my_apparent_addr = TOR_ADDR_NULL;
   int started_here = 0;
   const char *identity_digest = NULL;
@@ -1722,7 +1734,7 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan)
         tor_assert(tor_digest_is_zero(
                   (const char*)(chan->conn->handshake_state->
                       authenticated_rsa_peer_id)));
-        tor_assert(tor_mem_is_zero(
+        tor_assert(fast_mem_is_zero(
                   (const char*)(chan->conn->handshake_state->
                                 authenticated_ed25519_peer_id.pubkey), 32));
         /* If the client never authenticated, it's a tor client or bridge
@@ -1765,7 +1777,7 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan)
   my_addr_type = netinfo_addr_get_addr_type(my_addr);
   my_addr_len = netinfo_addr_get_len(my_addr);
 
-  if (labs(now - chan->conn->handshake_state->sent_versions_at) < 180) {
+  if ((now - chan->conn->handshake_state->sent_versions_at) < 180) {
     apparent_skew = now - timestamp;
   }
   /* We used to check:
@@ -1842,7 +1854,7 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan)
   /* Act on apparent skew. */
   /** Warn when we get a netinfo skew with at least this value. */
 #define NETINFO_NOTICE_SKEW 3600
-  if (labs(apparent_skew) > NETINFO_NOTICE_SKEW &&
+  if (time_abs(apparent_skew) > NETINFO_NOTICE_SKEW &&
       (started_here ||
        connection_or_digest_is_known_relay(chan->conn->identity_digest))) {
     int trusted = router_digest_is_trusted_dir(chan->conn->identity_digest);
diff --git a/src/core/or/circuit_st.h b/src/core/or/circuit_st.h
index af343f082..eae3c908d 100644
--- a/src/core/or/circuit_st.h
+++ b/src/core/or/circuit_st.h
@@ -13,7 +13,7 @@
 
 struct hs_token_t;
 struct circpad_machine_spec_t;
-struct circpad_machine_state_t;
+struct circpad_machine_runtime_t;
 
 /** Number of padding state machines on a circuit. */
 #define CIRCPAD_MAX_MACHINES (2)
@@ -66,12 +66,6 @@ struct circuit_t {
    */
   circid_t n_circ_id;
 
-  /**
-   * Circuit mux associated with n_chan to which this circuit is attached;
-   * NULL if we have no n_chan.
-   */
-  circuitmux_t *n_mux;
-
   /** Queue of cells waiting to be transmitted on n_chan */
   cell_queue_t n_chan_cells;
 
@@ -98,6 +92,10 @@ struct circuit_t {
   /** True iff this circuit has received a DESTROY cell in either direction */
   unsigned int received_destroy : 1;
 
+  /** True iff we have sent a sufficiently random data cell since last
+   * we reset send_randomness_after_n_cells. */
+  unsigned int have_sent_sufficiently_random_cell : 1;
+
   uint8_t state; /**< Current status of this circuit. */
   uint8_t purpose; /**< Why are we creating this circuit? */
 
@@ -110,6 +108,32 @@ struct circuit_t {
    * circuit-level sendme cells to indicate that we're willing to accept
    * more. */
   int deliver_window;
+  /**
+   * How many cells do we have until we need to send one that contains
+   * sufficient randomness?  Used to ensure that authenticated SENDME cells
+   * will reflect some unpredictable information.
+   **/
+  uint16_t send_randomness_after_n_cells;
+
+  /** FIFO containing the digest of the cells that are just before a SENDME is
+   * sent by the client. It is done at the last cell before our package_window
+   * goes down to 0 which is when we expect a SENDME.
+   *
+   * Our current circuit package window is capped to 1000
+   * (CIRCWINDOW_START_MAX) which is also the start value. The increment is
+   * set to 100 (CIRCWINDOW_INCREMENT) which means we don't allow more than
+   * 1000/100 = 10 outstanding SENDME cells worth of data. Meaning that this
+   * list can not contain more than 10 digests of DIGEST_LEN bytes (20).
+   *
+   * At position i in the list, the digest corresponds to the
+   * (CIRCWINDOW_INCREMENT * i)-nth cell received since we expect a SENDME to
+   * be received containing that cell digest.
+   *
+   * For example, position 2 (starting at 0) means that we've received 300
+   * cells so the 300th cell digest is kept at index 2.
+   *
+   * At maximum, this list contains 200 bytes plus the smartlist overhead. */
+  smartlist_t *sendme_last_digests;
 
   /** Temporary field used during circuits_handle_oom. */
   uint32_t age_tmp;
@@ -193,8 +217,8 @@ struct circuit_t {
    *  and we can have up to CIRCPAD_MAX_MACHINES such machines. */
   const struct circpad_machine_spec_t *padding_machine[CIRCPAD_MAX_MACHINES];
 
-  /** Adaptive Padding machine info for above machines. This is the
-   *  per-circuit mutable information, such as the current state and
+  /** Adaptive Padding machine runtime info for above machines. This is
+   *  the per-circuit mutable information, such as the current state and
    *  histogram token counts. Some of it is optional (aka NULL).
    *  If a machine is being shut down, these indexes can be NULL
    *  without the corresponding padding_machine being NULL, while we
@@ -202,7 +226,7 @@ struct circuit_t {
    *
    *  Each element of this array corresponds to a different padding machine,
    *  and we can have up to CIRCPAD_MAX_MACHINES such machines. */
-  struct circpad_machine_state_t *padding_info[CIRCPAD_MAX_MACHINES];
+  struct circpad_machine_runtime_t *padding_info[CIRCPAD_MAX_MACHINES];
 };
 
-#endif
+#endif /* !defined(CIRCUIT_ST_H) */
diff --git a/src/core/or/circuitbuild.c b/src/core/or/circuitbuild.c
index 3ec1e01f1..3a4e72942 100644
--- a/src/core/or/circuitbuild.c
+++ b/src/core/or/circuitbuild.c
@@ -51,11 +51,12 @@
 #include "core/or/ocirc_event.h"
 #include "core/or/policies.h"
 #include "core/or/relay.h"
+#include "core/or/crypt_path.h"
 #include "feature/client/bridges.h"
 #include "feature/client/circpathbias.h"
 #include "feature/client/entrynodes.h"
 #include "feature/client/transports.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dircommon/directory.h"
 #include "feature/nodelist/describe.h"
 #include "feature/nodelist/microdesc.h"
@@ -90,8 +91,6 @@ static channel_t * channel_connect_for_circuit(const tor_addr_t *addr,
 static int circuit_deliver_create_cell(circuit_t *circ,
                                        const create_cell_t *create_cell,
                                        int relayed);
-static crypt_path_t *onion_next_hop_in_cpath(crypt_path_t *cpath);
-STATIC int onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice);
 static int circuit_send_first_onion_skin(origin_circuit_t *circ);
 static int circuit_build_no_more_hops(origin_circuit_t *circ);
 static int circuit_send_intermediate_onion_skin(origin_circuit_t *circ,
@@ -547,7 +546,7 @@ circuit_handle_first_hop(origin_circuit_t *circ)
   int should_launch = 0;
   const or_options_t *options = get_options();
 
-  firsthop = onion_next_hop_in_cpath(circ->cpath);
+  firsthop = cpath_get_next_non_open_hop(circ->cpath);
   tor_assert(firsthop);
   tor_assert(firsthop->extend_info);
 
@@ -948,7 +947,7 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
   tor_assert(circ->cpath->state == CPATH_STATE_OPEN);
   tor_assert(circ->base_.state == CIRCUIT_STATE_BUILDING);
 
-  crypt_path_t *hop = onion_next_hop_in_cpath(circ->cpath);
+  crypt_path_t *hop = cpath_get_next_non_open_hop(circ->cpath);
   circuit_build_times_handle_completed_hop(circ);
 
   circpad_machine_event_circ_added_hop(circ);
@@ -1360,34 +1359,6 @@ circuit_extend(cell_t *cell, circuit_t *circ)
   return 0;
 }
 
-/** Initialize cpath-\>{f|b}_{crypto|digest} from the key material in key_data.
- *
- * If <b>is_hs_v3</b> is set, this cpath will be used for next gen hidden
- * service circuits and <b>key_data</b> must be at least
- * HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN bytes in length.
- *
- * If <b>is_hs_v3</b> is not set, key_data must contain CPATH_KEY_MATERIAL_LEN
- * bytes, which are used as follows:
- *   - 20 to initialize f_digest
- *   - 20 to initialize b_digest
- *   - 16 to key f_crypto
- *   - 16 to key b_crypto
- *
- * (If 'reverse' is true, then f_XX and b_XX are swapped.)
- *
- * Return 0 if init was successful, else -1 if it failed.
- */
-int
-circuit_init_cpath_crypto(crypt_path_t *cpath,
-                          const char *key_data, size_t key_data_len,
-                          int reverse, int is_hs_v3)
-{
-
-  tor_assert(cpath);
-  return relay_crypto_init(&cpath->crypto, key_data, key_data_len, reverse,
-                           is_hs_v3);
-}
-
 /** A "created" cell <b>reply</b> came back to us on circuit <b>circ</b>.
  * (The body of <b>reply</b> varies depending on what sort of handshake
  * this is.)
@@ -1413,7 +1384,7 @@ circuit_finish_handshake(origin_circuit_t *circ,
   if (circ->cpath->state == CPATH_STATE_AWAITING_KEYS) {
     hop = circ->cpath;
   } else {
-    hop = onion_next_hop_in_cpath(circ->cpath);
+    hop = cpath_get_next_non_open_hop(circ->cpath);
     if (!hop) { /* got an extended when we're all done? */
       log_warn(LD_PROTOCOL,"got extended when circ already built? Closing.");
       return - END_CIRC_REASON_TORPROTOCOL;
@@ -1437,7 +1408,7 @@ circuit_finish_handshake(origin_circuit_t *circ,
 
   onion_handshake_state_release(&hop->handshake_state);
 
-  if (circuit_init_cpath_crypto(hop, keys, sizeof(keys), 0, 0)<0) {
+  if (cpath_init_circuit_crypto(hop, keys, sizeof(keys), 0, 0)<0) {
     return -END_CIRC_REASON_TORPROTOCOL;
   }
 
@@ -1489,7 +1460,7 @@ circuit_truncated(origin_circuit_t *circ, int reason)
     }
 
     layer->next = victim->next;
-    circuit_free_cpath_node(victim);
+    cpath_free(victim);
   }
 
   log_info(LD_CIRC, "finished");
@@ -1683,7 +1654,8 @@ route_len_for_purpose(uint8_t purpose, extend_info_t *exit_ei)
  * to handle the desired path length, return -1.
  */
 STATIC int
-new_route_len(uint8_t purpose, extend_info_t *exit_ei, smartlist_t *nodes)
+new_route_len(uint8_t purpose, extend_info_t *exit_ei,
+              const smartlist_t *nodes)
 {
   int routelen;
 
@@ -2307,7 +2279,7 @@ circuit_append_new_exit(origin_circuit_t *circ, extend_info_t *exit_ei)
   state->chosen_exit = extend_info_dup(exit_ei);
 
   ++circ->build_state->desired_path_len;
-  onion_append_hop(&circ->cpath, exit_ei);
+  cpath_append_hop(&circ->cpath, exit_ei);
   return 0;
 }
 
@@ -2345,7 +2317,7 @@ circuit_extend_to_new_exit(origin_circuit_t *circ, extend_info_t *exit_ei)
  * particular router. See bug #25885.)
  */
 MOCK_IMPL(STATIC int,
-count_acceptable_nodes, (smartlist_t *nodes, int direct))
+count_acceptable_nodes, (const smartlist_t *nodes, int direct))
 {
   int num=0;
 
@@ -2372,47 +2344,6 @@ count_acceptable_nodes, (smartlist_t *nodes, int direct))
   return num;
 }
 
-/** Add <b>new_hop</b> to the end of the doubly-linked-list <b>head_ptr</b>.
- * This function is used to extend cpath by another hop.
- */
-void
-onion_append_to_cpath(crypt_path_t **head_ptr, crypt_path_t *new_hop)
-{
-  if (*head_ptr) {
-    new_hop->next = (*head_ptr);
-    new_hop->prev = (*head_ptr)->prev;
-    (*head_ptr)->prev->next = new_hop;
-    (*head_ptr)->prev = new_hop;
-  } else {
-    *head_ptr = new_hop;
-    new_hop->prev = new_hop->next = new_hop;
-  }
-}
-
-#ifdef TOR_UNIT_TESTS
-
-/** Unittest helper function: Count number of hops in cpath linked list. */
-unsigned int
-cpath_get_n_hops(crypt_path_t **head_ptr)
-{
-  unsigned int n_hops = 0;
-  crypt_path_t *tmp;
-
-  if (!*head_ptr) {
-    return 0;
-  }
-
-  tmp = *head_ptr;
-  do {
-    n_hops++;
-    tmp = tmp->next;
-  } while (tmp != *head_ptr);
-
-  return n_hops;
-}
-
-#endif /* defined(TOR_UNIT_TESTS) */
-
 /**
  * Build the exclude list for vanguard circuits.
  *
@@ -2687,20 +2618,6 @@ choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state,
   return choice;
 }
 
-/** Return the first non-open hop in cpath, or return NULL if all
- * hops are open. */
-static crypt_path_t *
-onion_next_hop_in_cpath(crypt_path_t *cpath)
-{
-  crypt_path_t *hop = cpath;
-  do {
-    if (hop->state != CPATH_STATE_OPEN)
-      return hop;
-    hop = hop->next;
-  } while (hop != cpath);
-  return NULL;
-}
-
 /** Choose a suitable next hop for the circuit <b>circ</b>.
  * Append the hop info to circ->cpath.
  *
@@ -2757,33 +2674,11 @@ onion_extend_cpath(origin_circuit_t *circ)
             extend_info_describe(info),
             cur_len+1, build_state_get_exit_nickname(state));
 
-  onion_append_hop(&circ->cpath, info);
+  cpath_append_hop(&circ->cpath, info);
   extend_info_free(info);
   return 0;
 }
 
-/** Create a new hop, annotate it with information about its
- * corresponding router <b>choice</b>, and append it to the
- * end of the cpath <b>head_ptr</b>. */
-STATIC int
-onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice)
-{
-  crypt_path_t *hop = tor_malloc_zero(sizeof(crypt_path_t));
-
-  /* link hop into the cpath, at the end. */
-  onion_append_to_cpath(head_ptr, hop);
-
-  hop->magic = CRYPT_PATH_MAGIC;
-  hop->state = CPATH_STATE_CLOSED;
-
-  hop->extend_info = extend_info_dup(choice);
-
-  hop->package_window = circuit_initial_package_window();
-  hop->deliver_window = CIRCWINDOW_START;
-
-  return 0;
-}
-
 /** Allocate a new extend_info object based on the various arguments. */
 extend_info_t *
 extend_info_new(const char *nickname,
@@ -2988,7 +2883,7 @@ extend_info_supports_ntor(const extend_info_t* ei)
 {
   tor_assert(ei);
   /* Valid ntor keys have at least one non-zero byte */
-  return !tor_mem_is_zero(
+  return !fast_mem_is_zero(
                           (const char*)ei->curve25519_onion_key.public_key,
                           CURVE25519_PUBKEY_LEN);
 }
diff --git a/src/core/or/circuitbuild.h b/src/core/or/circuitbuild.h
index b19bc4123..ad7d032cd 100644
--- a/src/core/or/circuitbuild.h
+++ b/src/core/or/circuitbuild.h
@@ -34,9 +34,6 @@ int circuit_timeout_want_to_count_circ(const origin_circuit_t *circ);
 int circuit_send_next_onion_skin(origin_circuit_t *circ);
 void circuit_note_clock_jumped(int64_t seconds_elapsed, bool was_idle);
 int circuit_extend(cell_t *cell, circuit_t *circ);
-int circuit_init_cpath_crypto(crypt_path_t *cpath,
-                              const char *key_data, size_t key_data_len,
-                              int reverse, int is_hs_v3);
 struct created_cell_t;
 int circuit_finish_handshake(origin_circuit_t *circ,
                              const struct created_cell_t *created_cell);
@@ -51,7 +48,6 @@ MOCK_DECL(int, circuit_all_predicted_ports_handled, (time_t now,
 
 int circuit_append_new_exit(origin_circuit_t *circ, extend_info_t *info);
 int circuit_extend_to_new_exit(origin_circuit_t *circ, extend_info_t *info);
-void onion_append_to_cpath(crypt_path_t **head_ptr, crypt_path_t *new_hop);
 extend_info_t *extend_info_new(const char *nickname,
                                const char *rsa_id_digest,
                                const struct ed25519_public_key_t *ed_id,
@@ -83,8 +79,8 @@ void circuit_upgrade_circuits_from_guard_wait(void);
 #ifdef CIRCUITBUILD_PRIVATE
 STATIC circid_t get_unique_circ_id_by_chan(channel_t *chan);
 STATIC int new_route_len(uint8_t purpose, extend_info_t *exit_ei,
-                         smartlist_t *nodes);
-MOCK_DECL(STATIC int, count_acceptable_nodes, (smartlist_t *nodes,
+                         const smartlist_t *nodes);
+MOCK_DECL(STATIC int, count_acceptable_nodes, (const smartlist_t *nodes,
                                                int direct));
 
 STATIC int onion_extend_cpath(origin_circuit_t *circ);
@@ -93,11 +89,6 @@ STATIC int
 onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit_ei,
                       int is_hs_v3_rp_circuit);
 
-#if defined(TOR_UNIT_TESTS)
-unsigned int cpath_get_n_hops(crypt_path_t **head_ptr);
-
-#endif /* defined(TOR_UNIT_TESTS) */
-
 #endif /* defined(CIRCUITBUILD_PRIVATE) */
 
 #endif /* !defined(TOR_CIRCUITBUILD_H) */
diff --git a/src/core/or/circuitlist.c b/src/core/or/circuitlist.c
index 6b5f30e41..ebbe7f082 100644
--- a/src/core/or/circuitlist.c
+++ b/src/core/or/circuitlist.c
@@ -63,11 +63,12 @@
 #include "core/or/circuituse.h"
 #include "core/or/circuitstats.h"
 #include "core/or/circuitpadding.h"
+#include "core/or/crypt_path.h"
 #include "core/mainloop/connection.h"
 #include "app/config/config.h"
 #include "core/or/connection_edge.h"
 #include "core/or/connection_or.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/crypt_ops/crypto_util.h"
 #include "lib/crypt_ops/crypto_dh.h"
@@ -132,7 +133,6 @@ static smartlist_t *circuits_pending_other_guards = NULL;
  * circuit_mark_for_close and which are waiting for circuit_about_to_free. */
 static smartlist_t *circuits_pending_close = NULL;
 
-static void circuit_free_cpath_node(crypt_path_t *victim);
 static void cpath_ref_decref(crypt_path_reference_t *cpath_ref);
 static void circuit_about_to_free_atexit(circuit_t *circ);
 static void circuit_about_to_free(circuit_t *circ);
@@ -823,6 +823,8 @@ circuit_purpose_to_controller_string(uint8_t purpose)
       return "PATH_BIAS_TESTING";
     case CIRCUIT_PURPOSE_HS_VANGUARDS:
       return "HS_VANGUARDS";
+    case CIRCUIT_PURPOSE_C_CIRCUIT_PADDING:
+      return "CIRCUIT_PADDING";
 
     default:
       tor_snprintf(buf, sizeof(buf), "UNKNOWN_%d", (int)purpose);
@@ -852,6 +854,7 @@ circuit_purpose_to_controller_hs_state_string(uint8_t purpose)
     case CIRCUIT_PURPOSE_CONTROLLER:
     case CIRCUIT_PURPOSE_PATH_BIAS_TESTING:
     case CIRCUIT_PURPOSE_HS_VANGUARDS:
+    case CIRCUIT_PURPOSE_C_CIRCUIT_PADDING:
       return NULL;
 
     case CIRCUIT_PURPOSE_INTRO_POINT:
@@ -952,6 +955,9 @@ circuit_purpose_to_string(uint8_t purpose)
     case CIRCUIT_PURPOSE_HS_VANGUARDS:
       return "Hidden service: Pre-built vanguard circuit";
 
+    case CIRCUIT_PURPOSE_C_CIRCUIT_PADDING:
+      return "Circuit kept open for padding";
+
     default:
       tor_snprintf(buf, sizeof(buf), "UNKNOWN_%d", (int)purpose);
       return buf;
@@ -987,6 +993,7 @@ init_circuit_base(circuit_t *circ)
 
   circ->package_window = circuit_initial_package_window();
   circ->deliver_window = CIRCWINDOW_START;
+  circuit_reset_sendme_randomness(circ);
   cell_queue_init(&circ->n_chan_cells);
 
   smartlist_add(circuit_get_global_list(), circ);
@@ -1148,7 +1155,7 @@ circuit_free_(circuit_t *circ)
 
     if (ocirc->build_state) {
         extend_info_free(ocirc->build_state->chosen_exit);
-        circuit_free_cpath_node(ocirc->build_state->pending_final_cpath);
+        cpath_free(ocirc->build_state->pending_final_cpath);
         cpath_ref_decref(ocirc->build_state->service_pending_final_cpath_ref);
     }
     tor_free(ocirc->build_state);
@@ -1227,6 +1234,12 @@ circuit_free_(circuit_t *circ)
    * "active" checks will be violated. */
   cell_queue_clear(&circ->n_chan_cells);
 
+  /* Cleanup possible SENDME state. */
+  if (circ->sendme_last_digests) {
+    SMARTLIST_FOREACH(circ->sendme_last_digests, uint8_t *, d, tor_free(d));
+    smartlist_free(circ->sendme_last_digests);
+  }
+
   log_info(LD_CIRC, "Circuit %u (id: %" PRIu32 ") has been freed.",
            n_circ_id,
            CIRCUIT_IS_ORIGIN(circ) ?
@@ -1266,10 +1279,10 @@ circuit_clear_cpath(origin_circuit_t *circ)
   while (cpath->next && cpath->next != head) {
     victim = cpath;
     cpath = victim->next;
-    circuit_free_cpath_node(victim);
+    cpath_free(victim);
   }
 
-  circuit_free_cpath_node(cpath);
+  cpath_free(cpath);
 
   circ->cpath = NULL;
 }
@@ -1326,29 +1339,13 @@ circuit_free_all(void)
   HT_CLEAR(chan_circid_map, &chan_circid_map);
 }
 
-/** Deallocate space associated with the cpath node <b>victim</b>. */
-static void
-circuit_free_cpath_node(crypt_path_t *victim)
-{
-  if (!victim)
-    return;
-
-  relay_crypto_clear(&victim->crypto);
-  onion_handshake_state_release(&victim->handshake_state);
-  crypto_dh_free(victim->rend_dh_handshake_state);
-  extend_info_free(victim->extend_info);
-
-  memwipe(victim, 0xBB, sizeof(crypt_path_t)); /* poison memory */
-  tor_free(victim);
-}
-
 /** Release a crypt_path_reference_t*, which may be NULL. */
 static void
 cpath_ref_decref(crypt_path_reference_t *cpath_ref)
 {
   if (cpath_ref != NULL) {
     if (--(cpath_ref->refcount) == 0) {
-      circuit_free_cpath_node(cpath_ref->cpath);
+      cpath_free(cpath_ref->cpath);
       tor_free(cpath_ref);
     }
   }
@@ -2199,6 +2196,11 @@ circuit_mark_for_close_, (circuit_t *circ, int reason, int line,
   tor_assert(line);
   tor_assert(file);
 
+  /* Check whether the circuitpadding subsystem wants to block this close */
+  if (circpad_marked_circuit_for_padding(circ, reason)) {
+    return;
+  }
+
   if (circ->marked_for_close) {
     log_warn(LD_BUG,
         "Duplicate call to circuit_mark_for_close at %s:%d"
@@ -2433,13 +2435,9 @@ marked_circuit_free_cells(circuit_t *circ)
     return;
   }
   cell_queue_clear(&circ->n_chan_cells);
-  if (circ->n_mux)
-    circuitmux_clear_num_cells(circ->n_mux, circ);
   if (! CIRCUIT_IS_ORIGIN(circ)) {
     or_circuit_t *orcirc = TO_OR_CIRCUIT(circ);
     cell_queue_clear(&orcirc->p_chan_cells);
-    if (orcirc->p_mux)
-      circuitmux_clear_num_cells(orcirc->p_mux, circ);
   }
 }
 
@@ -2783,59 +2781,6 @@ circuits_handle_oom(size_t current_allocation)
              n_dirconns_killed);
 }
 
-/** Verify that cpath layer <b>cp</b> has all of its invariants
- * correct. Trigger an assert if anything is invalid.
- */
-void
-assert_cpath_layer_ok(const crypt_path_t *cp)
-{
-//  tor_assert(cp->addr); /* these are zero for rendezvous extra-hops */
-//  tor_assert(cp->port);
-  tor_assert(cp);
-  tor_assert(cp->magic == CRYPT_PATH_MAGIC);
-  switch (cp->state)
-    {
-    case CPATH_STATE_OPEN:
-      relay_crypto_assert_ok(&cp->crypto);
-      /* fall through */
-    case CPATH_STATE_CLOSED:
-      /*XXXX Assert that there's no handshake_state either. */
-      tor_assert(!cp->rend_dh_handshake_state);
-      break;
-    case CPATH_STATE_AWAITING_KEYS:
-      /* tor_assert(cp->dh_handshake_state); */
-      break;
-    default:
-      log_fn(LOG_ERR, LD_BUG, "Unexpected state %d", cp->state);
-      tor_assert(0);
-    }
-  tor_assert(cp->package_window >= 0);
-  tor_assert(cp->deliver_window >= 0);
-}
-
-/** Verify that cpath <b>cp</b> has all of its invariants
- * correct. Trigger an assert if anything is invalid.
- */
-static void
-assert_cpath_ok(const crypt_path_t *cp)
-{
-  const crypt_path_t *start = cp;
-
-  do {
-    assert_cpath_layer_ok(cp);
-    /* layers must be in sequence of: "open* awaiting? closed*" */
-    if (cp != start) {
-      if (cp->state == CPATH_STATE_AWAITING_KEYS) {
-        tor_assert(cp->prev->state == CPATH_STATE_OPEN);
-      } else if (cp->state == CPATH_STATE_OPEN) {
-        tor_assert(cp->prev->state == CPATH_STATE_OPEN);
-      }
-    }
-    cp = cp->next;
-    tor_assert(cp);
-  } while (cp != start);
-}
-
 /** Verify that circuit <b>c</b> has all of its invariants
  * correct. Trigger an assert if anything is invalid.
  */
@@ -2897,7 +2842,7 @@ assert_circuit_ok,(const circuit_t *c))
                !smartlist_contains(circuits_pending_chans, c));
   }
   if (origin_circ && origin_circ->cpath) {
-    assert_cpath_ok(origin_circ->cpath);
+    cpath_assert_ok(origin_circ->cpath);
   }
   if (c->purpose == CIRCUIT_PURPOSE_REND_ESTABLISHED) {
     tor_assert(or_circ);
diff --git a/src/core/or/circuitlist.h b/src/core/or/circuitlist.h
index f34f4ed6b..80c1f7ac4 100644
--- a/src/core/or/circuitlist.h
+++ b/src/core/or/circuitlist.h
@@ -92,31 +92,33 @@
 #define CIRCUIT_PURPOSE_C_HS_MAX_ 13
 /** This circuit is used for build time measurement only */
 #define CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT 14
-#define CIRCUIT_PURPOSE_C_MAX_ 14
+/** This circuit is being held open by circuit padding */
+#define CIRCUIT_PURPOSE_C_CIRCUIT_PADDING 15
+#define CIRCUIT_PURPOSE_C_MAX_ 15
 
-#define CIRCUIT_PURPOSE_S_HS_MIN_ 15
+#define CIRCUIT_PURPOSE_S_HS_MIN_ 16
 /** Hidden-service-side circuit purpose: at the service, waiting for
  * introductions. */
-#define CIRCUIT_PURPOSE_S_ESTABLISH_INTRO 15
+#define CIRCUIT_PURPOSE_S_ESTABLISH_INTRO 16
 /** Hidden-service-side circuit purpose: at the service, successfully
  * established intro. */
-#define CIRCUIT_PURPOSE_S_INTRO 16
+#define CIRCUIT_PURPOSE_S_INTRO 17
 /** Hidden-service-side circuit purpose: at the service, connecting to rend
  * point. */
-#define CIRCUIT_PURPOSE_S_CONNECT_REND 17
+#define CIRCUIT_PURPOSE_S_CONNECT_REND 18
 /** Hidden-service-side circuit purpose: at the service, rendezvous
  * established. */
-#define CIRCUIT_PURPOSE_S_REND_JOINED 18
+#define CIRCUIT_PURPOSE_S_REND_JOINED 19
 /** This circuit is used for uploading hsdirs */
-#define CIRCUIT_PURPOSE_S_HSDIR_POST 19
-#define CIRCUIT_PURPOSE_S_HS_MAX_ 19
+#define CIRCUIT_PURPOSE_S_HSDIR_POST 20
+#define CIRCUIT_PURPOSE_S_HS_MAX_ 20
 
 /** A testing circuit; not meant to be used for actual traffic. */
-#define CIRCUIT_PURPOSE_TESTING 20
+#define CIRCUIT_PURPOSE_TESTING 21
 /** A controller made this circuit and Tor should not use it. */
-#define CIRCUIT_PURPOSE_CONTROLLER 21
+#define CIRCUIT_PURPOSE_CONTROLLER 22
 /** This circuit is used for path bias probing only */
-#define CIRCUIT_PURPOSE_PATH_BIAS_TESTING 22
+#define CIRCUIT_PURPOSE_PATH_BIAS_TESTING 23
 
 /** This circuit is used for vanguards/restricted paths.
  *
@@ -124,9 +126,9 @@
  *  on-demand. When an HS operation needs to take place (e.g. connect to an
  *  intro point), these circuits are then cannibalized and repurposed to the
  *  actual needed HS purpose. */
-#define CIRCUIT_PURPOSE_HS_VANGUARDS 23
+#define CIRCUIT_PURPOSE_HS_VANGUARDS 24
 
-#define CIRCUIT_PURPOSE_MAX_ 23
+#define CIRCUIT_PURPOSE_MAX_ 24
 /** A catch-all for unrecognized purposes. Currently we don't expect
  * to make or see any circuits with this purpose. */
 #define CIRCUIT_PURPOSE_UNKNOWN 255
@@ -216,7 +218,7 @@ void circuit_mark_all_dirty_circs_as_unusable(void);
 void circuit_synchronize_written_or_bandwidth(const circuit_t *c,
                                               circuit_channel_direction_t dir);
 MOCK_DECL(void, circuit_mark_for_close_, (circuit_t *circ, int reason,
-                                          int line, const char *file));
+                                          int line, const char *cfile));
 int circuit_get_cpath_len(origin_circuit_t *circ);
 int circuit_get_cpath_opened_len(const origin_circuit_t *);
 void circuit_clear_cpath(origin_circuit_t *circ);
@@ -228,7 +230,6 @@ int circuit_count_pending_on_channel(channel_t *chan);
 #define circuit_mark_for_close(c, reason)                               \
   circuit_mark_for_close_((c), (reason), __LINE__, SHORT_FILE__)
 
-void assert_cpath_layer_ok(const crypt_path_t *cp);
 MOCK_DECL(void, assert_circuit_ok,(const circuit_t *c));
 void circuit_free_all(void);
 void circuits_handle_oom(size_t current_allocation);
diff --git a/src/core/or/circuitmux.c b/src/core/or/circuitmux.c
index 88f9ac792..b2628bec3 100644
--- a/src/core/or/circuitmux.c
+++ b/src/core/or/circuitmux.c
@@ -294,9 +294,6 @@ circuitmux_detach_all_circuits(circuitmux_t *cmux, smartlist_t *detached_out)
               circuitmux_make_circuit_inactive(cmux, circ);
             }
 
-            /* Clear n_mux */
-            circ->n_mux = NULL;
-
             if (detached_out)
               smartlist_add(detached_out, circ);
           } else if (circ->magic == OR_CIRCUIT_MAGIC) {
@@ -309,12 +306,6 @@ circuitmux_detach_all_circuits(circuitmux_t *cmux, smartlist_t *detached_out)
               circuitmux_make_circuit_inactive(cmux, circ);
             }
 
-            /*
-             * It has a sensible p_chan and direction == CELL_DIRECTION_IN,
-             * so clear p_mux.
-             */
-            TO_OR_CIRCUIT(circ)->p_mux = NULL;
-
             if (detached_out)
               smartlist_add(detached_out, circ);
           } else {
@@ -836,18 +827,14 @@ circuitmux_attach_circuit,(circuitmux_t *cmux, circuit_t *circ,
      */
     log_info(LD_CIRC,
              "Circuit %u on channel %"PRIu64 " was already attached to "
-             "cmux %p (trying to attach to %p)",
+             "(trying to attach to %p)",
              (unsigned)circ_id, (channel_id),
-             ((direction == CELL_DIRECTION_OUT) ?
-                circ->n_mux : TO_OR_CIRCUIT(circ)->p_mux),
              cmux);
 
     /*
      * The mux pointer on this circuit and the direction in result should
      * match; otherwise assert.
      */
-    if (direction == CELL_DIRECTION_OUT) tor_assert(circ->n_mux == cmux);
-    else tor_assert(TO_OR_CIRCUIT(circ)->p_mux == cmux);
     tor_assert(hashent->muxinfo.direction == direction);
 
     /*
@@ -872,13 +859,6 @@ circuitmux_attach_circuit,(circuitmux_t *cmux, circuit_t *circ,
              "Attaching circuit %u on channel %"PRIu64 " to cmux %p",
               (unsigned)circ_id, (channel_id), cmux);
 
-    /*
-     * Assert that the circuit doesn't already have a mux for this
-     * direction.
-     */
-    if (direction == CELL_DIRECTION_OUT) tor_assert(circ->n_mux == NULL);
-    else tor_assert(TO_OR_CIRCUIT(circ)->p_mux == NULL);
-
     /* Insert it in the map */
     hashent = tor_malloc_zero(sizeof(*hashent));
     hashent->chan_id = channel_id;
@@ -902,10 +882,6 @@ circuitmux_attach_circuit,(circuitmux_t *cmux, circuit_t *circ,
     HT_INSERT(chanid_circid_muxinfo_map, cmux->chanid_circid_map,
               hashent);
 
-    /* Set the circuit's mux for this direction */
-    if (direction == CELL_DIRECTION_OUT) circ->n_mux = cmux;
-    else TO_OR_CIRCUIT(circ)->p_mux = cmux;
-
     /* Update counters */
     ++(cmux->n_circuits);
     if (cell_count > 0) {
@@ -993,9 +969,6 @@ circuitmux_detach_circuit,(circuitmux_t *cmux, circuit_t *circ))
 
     /* Consistency check: the direction must match the direction searched */
     tor_assert(last_searched_direction == hashent->muxinfo.direction);
-    /* Clear the circuit's mux for this direction */
-    if (last_searched_direction == CELL_DIRECTION_OUT) circ->n_mux = NULL;
-    else TO_OR_CIRCUIT(circ)->p_mux = NULL;
 
     /* Now remove it from the map */
     HT_REMOVE(chanid_circid_muxinfo_map, cmux->chanid_circid_map, hashent);
diff --git a/src/core/or/circuitpadding.c b/src/core/or/circuitpadding.c
index aa38b0ffc..a62cdcf9e 100644
--- a/src/core/or/circuitpadding.c
+++ b/src/core/or/circuitpadding.c
@@ -23,7 +23,7 @@
  * As specified by prop#254, clients can negotiate padding with relays by using
  * PADDING_NEGOTIATE cells. After successful padding negotiation, padding
  * machines are assigned to the circuit in their mutable form as a
- * circpad_machine_state_t.
+ * circpad_machine_runtime_t.
  *
  * Each state of a padding state machine can be either:
  * - A histogram that specifies inter-arrival padding delays.
@@ -37,6 +37,13 @@
  * When a padding machine reaches the END state, it gets wiped from the circuit
  * so that other padding machines can take over if needed (see
  * circpad_machine_spec_transitioned_to_end()).
+ *
+ ****************************
+ * General notes:
+ *
+ * All used machines should be heap allocated and placed into
+ * origin_padding_machines/relay_padding_machines so that they get correctly
+ * cleaned up by the circpad_free_all() function.
  **/
 
 #define CIRCUITPADDING_PRIVATE
@@ -46,8 +53,10 @@
 #include "lib/math/prob_distr.h"
 #include "core/or/or.h"
 #include "core/or/circuitpadding.h"
+#include "core/or/circuitpadding_machines.h"
 #include "core/or/circuitlist.h"
 #include "core/or/circuituse.h"
+#include "core/mainloop/netstatus.h"
 #include "core/or/relay.h"
 #include "feature/stats/rephist.h"
 #include "feature/nodelist/networkstatus.h"
@@ -71,15 +80,18 @@
 
 #include "app/config/config.h"
 
-static inline circpad_purpose_mask_t circpad_circ_purpose_to_mask(uint8_t
-                                          circ_purpose);
 static inline circpad_circuit_state_t circpad_circuit_state(
                                         origin_circuit_t *circ);
 static void circpad_setup_machine_on_circ(circuit_t *on_circ,
                                         const circpad_machine_spec_t *machine);
 static double circpad_distribution_sample(circpad_distribution_t dist);
 
+static inline void circpad_machine_update_state_length_for_nonpadding(
+        circpad_machine_runtime_t *mi);
+
 /** Cached consensus params */
+static uint8_t circpad_padding_disabled;
+static uint8_t circpad_padding_reduced;
 static uint8_t circpad_global_max_padding_percent;
 static uint16_t circpad_global_allowed_cells;
 static uint16_t circpad_max_circ_queued_cells;
@@ -120,40 +132,17 @@ STATIC smartlist_t *relay_padding_machines = NULL;
 #define FOR_EACH_ACTIVE_CIRCUIT_MACHINE_END } STMT_END ;
 
 /**
- * Return a human-readable description for a circuit padding state.
- */
-static const char *
-circpad_state_to_string(circpad_statenum_t state)
-{
-  const char *descr;
-
-  switch (state) {
-  case CIRCPAD_STATE_START:
-    descr = "START";
-    break;
-  case CIRCPAD_STATE_BURST:
-    descr = "BURST";
-    break;
-  case CIRCPAD_STATE_GAP:
-    descr = "GAP";
-    break;
-  case CIRCPAD_STATE_END:
-    descr = "END";
-    break;
-  default:
-    descr = "CUSTOM"; // XXX: Just return # in static char buf?
-  }
-
-  return descr;
-}
-
-/**
  * Free the machineinfo at an index
  */
 static void
 circpad_circuit_machineinfo_free_idx(circuit_t *circ, int idx)
 {
   if (circ->padding_info[idx]) {
+    log_fn(LOG_INFO,LD_CIRC, "Freeing padding info idx %d on circuit %u (%d)",
+           idx, CIRCUIT_IS_ORIGIN(circ) ?
+             TO_ORIGIN_CIRCUIT(circ)->global_identifier : 0,
+           circ->purpose);
+
     tor_free(circ->padding_info[idx]->histogram);
     timer_free(circ->padding_info[idx]->padding_timer);
     tor_free(circ->padding_info[idx]);
@@ -161,6 +150,118 @@ circpad_circuit_machineinfo_free_idx(circuit_t *circ, int idx)
 }
 
 /**
+ * Return true if circpad has decided to hold the circuit open for additional
+ * padding. This function is used to take and retain ownership of certain
+ * types of circuits that have padding machines on them, that have been passed
+ * to circuit_mark_for_close().
+ *
+ * circuit_mark_for_close() calls this function to ask circpad if any padding
+ * machines want to keep the circuit open longer to pad.
+ *
+ * Any non-measurement circuit that was closed for a normal, non-error reason
+ * code may be held open for up to CIRCPAD_DELAY_INFINITE microseconds between
+ * network-driven cell events.
+ *
+ * After CIRCPAD_DELAY_INFINITE microseconds of silence on a circuit, this
+ * function will no longer hold it open (it will return 0 regardless of
+ * what the machines ask for, and thus circuit_expire_old_circuits_clientside()
+ * will close the circuit after roughly 1.25hr of idle time, maximum,
+ * regardless of the padding machine state.
+ */
+int
+circpad_marked_circuit_for_padding(circuit_t *circ, int reason)
+{
+  /* If the circuit purpose is measurement or path bias, don't
+   * hold it open */
+  if (circ->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING ||
+      circ->purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) {
+    return 0;
+  }
+
+  /* If the circuit is closed for any reason other than these three valid,
+   * client-side close reasons, do not try to keep it open. It is probably
+   * damaged or unusable. Note this is OK with vanguards because
+   * controller-closed circuits have REASON=REQUESTED, so vanguards-closed
+   * circuits will not be held open (we want them to close ASAP). */
+  if (!(reason == END_CIRC_REASON_NONE ||
+        reason == END_CIRC_REASON_FINISHED ||
+        reason == END_CIRC_REASON_IP_NOW_REDUNDANT)) {
+    return 0;
+  }
+
+  FOR_EACH_ACTIVE_CIRCUIT_MACHINE_BEGIN(i, circ) {
+    circpad_machine_runtime_t *mi = circ->padding_info[i];
+    if (!mi) {
+      continue; // No padding runtime info; check next machine
+    }
+
+    const circpad_state_t *state = circpad_machine_current_state(mi);
+
+    /* If we're in END state (NULL here), then check next machine */
+    if (!state) {
+      continue; // check next machine
+    }
+
+    /* If the machine does not want to control the circuit close itself, then
+     * check the next machine */
+    if (!circ->padding_machine[i]->manage_circ_lifetime) {
+      continue; // check next machine
+    }
+
+    /* If the machine has reached the END state, we can close. Check next
+     * machine. */
+    if (mi->current_state == CIRCPAD_STATE_END) {
+      continue; // check next machine
+    }
+
+    log_info(LD_CIRC, "Circuit %d is not marked for close because of a "
+             "pending padding machine in index %d.",
+             CIRCUIT_IS_ORIGIN(circ) ?
+             TO_ORIGIN_CIRCUIT(circ)->global_identifier : 0, i);
+
+    /* If the machine has had no network events at all within the
+     * last circpad_delay_t timespan, it's in some deadlock state.
+     * Tell circuit_mark_for_close() that we don't own it anymore.
+     * This will allow circuit_expire_old_circuits_clientside() to
+     * close it.
+     */
+    if (circ->padding_info[i]->last_cell_time_sec +
+        (time_t)CIRCPAD_DELAY_MAX_SECS < approx_time()) {
+      log_notice(LD_BUG, "Circuit %d was not marked for close because of a "
+               "pending padding machine in index %d for over an hour. "
+               "Circuit is a %s",
+               CIRCUIT_IS_ORIGIN(circ) ?
+               TO_ORIGIN_CIRCUIT(circ)->global_identifier : 0,
+               i, circuit_purpose_to_string(circ->purpose));
+
+      return 0; // abort timer reached; mark the circuit for close now
+    }
+
+    /* If we weren't marked dirty yet, let's pretend we're dirty now.
+     * ("Dirty" means that a circuit has been used for application traffic
+     * by Tor.. Dirty circuits have different expiry times, and are not
+     * considered in counts of built circuits, etc. By claiming that we're
+     * dirty, the rest of Tor will make decisions as if we were actually
+     * used by application data.
+     *
+     * This is most important for circuit_expire_old_circuits_clientside(),
+     * where we want that function to expire us after the padding machine
+     * has shut down, but using the MaxCircuitDirtiness timer instead of
+     * the idle circuit timer (again, we want this because we're not
+     * supposed to look idle to Guard nodes that can see our lifespan). */
+    if (!circ->timestamp_dirty)
+      circ->timestamp_dirty = approx_time();
+
+    /* Take ownership of the circuit */
+    circuit_change_purpose(circ, CIRCUIT_PURPOSE_C_CIRCUIT_PADDING);
+
+    return 1;
+  } FOR_EACH_ACTIVE_CIRCUIT_MACHINE_END;
+
+  return 0; // No machine wanted to keep the circuit open; mark for close
+}
+
+/**
  * Free all the machineinfos in <b>circ</b> that match <b>machine_num</b>.
  *
  * Returns true if any machineinfos with that number were freed.
@@ -195,13 +296,14 @@ circpad_circuit_free_all_machineinfos(circuit_t *circ)
 /**
  * Allocate a new mutable machineinfo structure.
  */
-STATIC circpad_machine_state_t *
+STATIC circpad_machine_runtime_t *
 circpad_circuit_machineinfo_new(circuit_t *on_circ, int machine_index)
 {
-  circpad_machine_state_t *mi =
-    tor_malloc_zero(sizeof(circpad_machine_state_t));
+  circpad_machine_runtime_t *mi =
+    tor_malloc_zero(sizeof(circpad_machine_runtime_t));
   mi->machine_index = machine_index;
   mi->on_circ = on_circ;
+  mi->last_cell_time_sec = approx_time();
 
   return mi;
 }
@@ -214,7 +316,7 @@ circpad_circuit_machineinfo_new(circuit_t *on_circ, int machine_index)
  * invalid state.
  */
 STATIC const circpad_state_t *
-circpad_machine_current_state(const circpad_machine_state_t *mi)
+circpad_machine_current_state(const circpad_machine_runtime_t *mi)
 {
   const circpad_machine_spec_t *machine = CIRCPAD_GET_MACHINE(mi);
 
@@ -232,25 +334,20 @@ circpad_machine_current_state(const circpad_machine_state_t *mi)
 }
 
 /**
- * Calculate the lower bound of a histogram bin. The upper bound
- * is obtained by calling this function with bin+1, and subtracting 1.
+ * Get the lower bound of a histogram bin.
  *
- * The 0th bin has a special value -- it only represents start_usec.
- * This is so we can specify a probability on 0-delay values.
+ * You can obtain the upper bound using histogram_get_bin_upper_bound().
  *
- * After bin 0, bins are exponentially spaced, so that each subsequent
- * bin is twice as large as the previous. This is done so that higher
- * time resolution is given to lower time values.
- *
- * The infinity bin is a the last bin in the array (histogram_len-1).
- * It has a usec value of CIRCPAD_DELAY_INFINITE (UINT32_MAX).
+ * This function can also be called with 'bin' set to a value equal or greater
+ * than histogram_len in which case the infinity bin is chosen and
+ * CIRCPAD_DELAY_INFINITE is returned.
  */
 STATIC circpad_delay_t
-circpad_histogram_bin_to_usec(const circpad_machine_state_t *mi,
+circpad_histogram_bin_to_usec(const circpad_machine_runtime_t *mi,
                               circpad_hist_index_t bin)
 {
   const circpad_state_t *state = circpad_machine_current_state(mi);
-  circpad_delay_t start_usec;
+  circpad_delay_t rtt_add_usec = 0;
 
   /* Our state should have been checked to be non-null by the caller
    * (circpad_machine_remove_token()) */
@@ -258,37 +355,38 @@ circpad_histogram_bin_to_usec(const circpad_machine_state_t *mi,
     return CIRCPAD_DELAY_INFINITE;
   }
 
-  if (state->use_rtt_estimate)
-    start_usec = mi->rtt_estimate_usec+state->start_usec;
-  else
-    start_usec = state->start_usec;
-
-  if (bin >= CIRCPAD_INFINITY_BIN(state))
+  /* The infinity bin has an upper bound of infinity, so make sure we return
+   * that if they ask for it. */
+  if (bin > CIRCPAD_INFINITY_BIN(state)) {
     return CIRCPAD_DELAY_INFINITE;
+  }
 
-  if (bin == 0)
-    return start_usec;
+  /* If we are using an RTT estimate, consider it as well. */
+  if (state->use_rtt_estimate) {
+    rtt_add_usec = mi->rtt_estimate_usec;
+  }
 
-  if (bin == 1)
-    return start_usec+1;
+  return state->histogram_edges[bin] + rtt_add_usec;
+}
 
-  /* The bin widths double every index, so that we can have more resolution
-   * for lower time values in the histogram. */
-  const circpad_time_t bin_width_exponent =
-        1 << (CIRCPAD_INFINITY_BIN(state) - bin);
-  return (circpad_delay_t)MIN(start_usec +
-                              state->range_usec/bin_width_exponent,
-                              CIRCPAD_DELAY_INFINITE);
+/**
+ * Like circpad_histogram_bin_to_usec() but return the upper bound of bin.
+ * (The upper bound is included in the bin.)
+ */
+STATIC circpad_delay_t
+histogram_get_bin_upper_bound(const circpad_machine_runtime_t *mi,
+                              circpad_hist_index_t bin)
+{
+  return circpad_histogram_bin_to_usec(mi, bin+1) - 1;
 }
 
 /** Return the midpoint of the histogram bin <b>bin_index</b>. */
 static circpad_delay_t
-circpad_get_histogram_bin_midpoint(const circpad_machine_state_t *mi,
+circpad_get_histogram_bin_midpoint(const circpad_machine_runtime_t *mi,
                            int bin_index)
 {
   circpad_delay_t left_bound = circpad_histogram_bin_to_usec(mi, bin_index);
-  circpad_delay_t right_bound =
-    circpad_histogram_bin_to_usec(mi, bin_index+1)-1;
+  circpad_delay_t right_bound = histogram_get_bin_upper_bound(mi, bin_index);
 
   return left_bound + (right_bound - left_bound)/2;
 }
@@ -297,19 +395,17 @@ circpad_get_histogram_bin_midpoint(const circpad_machine_state_t *mi,
  * Return the bin that contains the usec argument.
  * "Contains" is defined as us in [lower, upper).
  *
- * This function will never return the infinity bin (histogram_len-1),
- * in order to simplify the rest of the code.
- *
- * This means that technically the last bin (histogram_len-2)
- * has range [start_usec+range_usec, CIRCPAD_DELAY_INFINITE].
+ * This function will never return the infinity bin (histogram_len-1), in order
+ * to simplify the rest of the code, so if a usec is provided that falls above
+ * the highest non-infinity bin, that bin index will be returned.
  */
 STATIC circpad_hist_index_t
-circpad_histogram_usec_to_bin(const circpad_machine_state_t *mi,
+circpad_histogram_usec_to_bin(const circpad_machine_runtime_t *mi,
                               circpad_delay_t usec)
 {
   const circpad_state_t *state = circpad_machine_current_state(mi);
-  circpad_delay_t start_usec;
-  int32_t bin; /* Larger than return type to properly clamp overflow */
+  circpad_delay_t rtt_add_usec = 0;
+  circpad_hist_index_t bin;
 
   /* Our state should have been checked to be non-null by the caller
    * (circpad_machine_remove_token()) */
@@ -317,34 +413,61 @@ circpad_histogram_usec_to_bin(const circpad_machine_state_t *mi,
     return 0;
   }
 
-  if (state->use_rtt_estimate)
-    start_usec = mi->rtt_estimate_usec+state->start_usec;
-  else
-    start_usec = state->start_usec;
+  /* If we are using an RTT estimate, consider it as well. */
+  if (state->use_rtt_estimate) {
+    rtt_add_usec = mi->rtt_estimate_usec;
+  }
 
-  /* The first bin (#0) has zero width and starts (and ends) at start_usec. */
-  if (usec <= start_usec)
-    return 0;
+  /* Walk through the bins and check the upper bound of each bin, if 'usec' is
+   * less-or-equal to that, return that bin. If rtt_estimate is enabled then
+   * add that to the upper bound of each bin.
+   *
+   * We don't want to return the infinity bin here, so don't go there. */
+  for (bin = 0 ; bin < CIRCPAD_INFINITY_BIN(state) ; bin++) {
+    if (usec <= histogram_get_bin_upper_bound(mi, bin) + rtt_add_usec) {
+      return bin;
+    }
+  }
 
-  if (usec == start_usec+1)
-    return 1;
+  /* We don't want to return the infinity bin here, so if we still didn't find
+   * the right bin, return the highest non-infinity bin */
+  return CIRCPAD_INFINITY_BIN(state)-1;
+}
 
-  const circpad_time_t histogram_range_usec = state->range_usec;
-  /* We need to find the bin corresponding to our position in the range.
-   * Since bins are exponentially spaced in powers of two, we need to
-   * take the log2 of our position in histogram_range_usec. However,
-   * since tor_log2() returns the floor(log2(u64)), we have to adjust
-   * it to behave like ceil(log2(u64)). This is verified in our tests
-   * to properly invert the operation done in
-   * circpad_histogram_bin_to_usec(). */
-  bin = CIRCPAD_INFINITY_BIN(state) -
-    tor_log2(2*histogram_range_usec/(usec-start_usec+1));
+/**
+ * Return true if the machine supports token removal.
+ *
+ * Token removal is equivalent to having a mutable histogram in the
+ * circpad_machine_runtime_t mutable info. So while we're at it,
+ * let's assert that everything is consistent between the mutable
+ * runtime and the readonly machine spec.
+ */
+static inline int
+circpad_is_token_removal_supported(circpad_machine_runtime_t *mi)
+{
+  /* No runtime histogram == no token removal */
+  if (mi->histogram == NULL) {
+    /* Machines that don't want token removal are trying to avoid
+     * potentially expensive mallocs, extra memory accesses, and/or
+     * potentially expensive monotime calls. Let's minimize checks
+     * and keep this path fast. */
+    tor_assert_nonfatal(mi->histogram_len == 0);
+    return 0;
+  } else {
+    /* Machines that do want token removal are less sensitive to performance.
+     * Let's spend some time to check that our state is consistent and sane */
+    const circpad_state_t *state = circpad_machine_current_state(mi);
+    if (BUG(!state)) {
+      return 1;
+    }
+    tor_assert_nonfatal(state->token_removal != CIRCPAD_TOKEN_REMOVAL_NONE);
+    tor_assert_nonfatal(state->histogram_len == mi->histogram_len);
+    tor_assert_nonfatal(mi->histogram_len != 0);
+    return 1;
+  }
 
-  /* Clamp the return value to account for timevals before the start
-   * of bin 0, or after the last bin. Don't return the infinity bin
-   * index. */
-  bin = MIN(MAX(bin, 1), CIRCPAD_INFINITY_BIN(state)-1);
-  return bin;
+  tor_assert_nonfatal_unreached();
+  return 0;
 }
 
 /**
@@ -353,12 +476,15 @@ circpad_histogram_usec_to_bin(const circpad_machine_state_t *mi,
  * Called after a state transition, or if the bins are empty.
  */
 STATIC void
-circpad_machine_setup_tokens(circpad_machine_state_t *mi)
+circpad_machine_setup_tokens(circpad_machine_runtime_t *mi)
 {
   const circpad_state_t *state = circpad_machine_current_state(mi);
 
   /* If this state doesn't exist, or doesn't have token removal,
-   * free any previous state's histogram, and bail */
+   * free any previous state's runtime histogram, and bail.
+   *
+   * If we don't have a token removal strategy, we also don't need a runtime
+   * histogram and we rely on the immutable one in machine_spec_t. */
   if (!state || state->token_removal == CIRCPAD_TOKEN_REMOVAL_NONE) {
     if (mi->histogram) {
       tor_free(mi->histogram);
@@ -385,7 +511,7 @@ circpad_machine_setup_tokens(circpad_machine_state_t *mi)
  * Choose a length for this state (in cells), if specified.
  */
 static void
-circpad_choose_state_length(circpad_machine_state_t *mi)
+circpad_choose_state_length(circpad_machine_runtime_t *mi)
 {
   const circpad_state_t *state = circpad_machine_current_state(mi);
   double length;
@@ -398,28 +524,40 @@ circpad_choose_state_length(circpad_machine_state_t *mi)
   length = circpad_distribution_sample(state->length_dist);
   length = MAX(0, length);
   length += state->start_length;
-  length = MIN(length, state->max_length);
+
+  if (state->max_length) {
+    length = MIN(length, state->max_length);
+  }
 
   mi->state_length = clamp_double_to_int64(length);
+
+  log_info(LD_CIRC, "State length sampled to %"PRIu64" for circuit %u",
+      mi->state_length, CIRCUIT_IS_ORIGIN(mi->on_circ) ?
+             TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier : 0);
 }
 
 /**
  * Sample a value from our iat_dist, and clamp it safely
  * to circpad_delay_t.
+ *
+ * Before returning, add <b>delay_shift</b> (can be zero) to the sampled value.
  */
 static circpad_delay_t
 circpad_distribution_sample_iat_delay(const circpad_state_t *state,
-                                      circpad_delay_t start_usec)
+                                      circpad_delay_t delay_shift)
 {
   double val = circpad_distribution_sample(state->iat_dist);
   /* These comparisons are safe, because the output is in the range
    * [0, 2**32), and double has a precision of 53 bits. */
+  /* We want a positive sample value */
   val = MAX(0, val);
-  val = MIN(val, state->range_usec);
+  /* Respect the maximum sample setting */
+  val = MIN(val, state->dist_max_sample_usec);
 
-  /* This addition is exact: val is at most 2**32-1, start_usec
-   * is at most 2**32-1, and doubles have a precision of 53 bits. */
-  val += start_usec;
+  /* Now apply the shift:
+   * This addition is exact: val is at most 2**32-1, delay_shift is at most
+   * 2**32-1, and doubles have a precision of 53 bits. */
+  val += delay_shift;
 
   /* Clamp the distribution at infinite delay val */
   return (circpad_delay_t)MIN(tor_llround(val), CIRCPAD_DELAY_INFINITE);
@@ -433,13 +571,12 @@ circpad_distribution_sample_iat_delay(const circpad_state_t *state,
  * that bin's [start,end) time range.
  */
 STATIC circpad_delay_t
-circpad_machine_sample_delay(circpad_machine_state_t *mi)
+circpad_machine_sample_delay(circpad_machine_runtime_t *mi)
 {
   const circpad_state_t *state = circpad_machine_current_state(mi);
   const circpad_hist_token_t *histogram = NULL;
   circpad_hist_index_t curr_bin = 0;
   circpad_delay_t bin_start, bin_end;
-  circpad_delay_t start_usec;
   /* These three must all be larger than circpad_hist_token_t, because
    * we sum several circpad_hist_token_t values across the histogram */
   uint64_t curr_weight = 0;
@@ -448,21 +585,13 @@ circpad_machine_sample_delay(circpad_machine_state_t *mi)
 
   tor_assert(state);
 
-  if (state->use_rtt_estimate)
-    start_usec = mi->rtt_estimate_usec+state->start_usec;
-  else
-    start_usec = state->start_usec;
-
   if (state->iat_dist.type != CIRCPAD_DIST_NONE) {
     /* Sample from a fixed IAT distribution and return */
-    return circpad_distribution_sample_iat_delay(state, start_usec);
-  } else if (state->token_removal != CIRCPAD_TOKEN_REMOVAL_NONE) {
-    /* We have a mutable histogram. Do basic sanity check and apply: */
-    if (BUG(!mi->histogram) ||
-        BUG(mi->histogram_len != state->histogram_len)) {
-      return CIRCPAD_DELAY_INFINITE;
-    }
-
+    circpad_delay_t iat_delay_shift = state->use_rtt_estimate ?
+      mi->rtt_estimate_usec + state->dist_added_shift_usec :
+      state->dist_added_shift_usec;
+    return circpad_distribution_sample_iat_delay(state, iat_delay_shift);
+  } else if (circpad_is_token_removal_supported(mi)) {
     histogram = mi->histogram;
     for (circpad_hist_index_t b = 0; b < state->histogram_len; b++)
       histogram_total_tokens += histogram[b];
@@ -472,7 +601,13 @@ circpad_machine_sample_delay(circpad_machine_state_t *mi)
     histogram_total_tokens = state->histogram_total_tokens;
   }
 
-  bin_choice = crypto_rand_uint64(histogram_total_tokens);
+  /* If we are out of tokens, don't schedule padding. */
+  if (!histogram_total_tokens) {
+    return CIRCPAD_DELAY_INFINITE;
+  }
+
+  bin_choice = crypto_fast_rng_get_uint64(get_thread_fast_rng(),
+                                          histogram_total_tokens);
 
   /* Skip all the initial zero bins */
   while (!histogram[curr_bin]) {
@@ -520,16 +655,13 @@ circpad_machine_sample_delay(circpad_machine_state_t *mi)
    * function below samples from [bin_start, bin_end) */
   bin_end = circpad_histogram_bin_to_usec(mi, curr_bin+1);
 
-  /* Truncate the high bin in case it's the infinity bin:
-   * Don't actually schedule an "infinite"-1 delay */
-  bin_end = MIN(bin_end, start_usec+state->range_usec);
-
-  // Sample uniformly between histogram[i] to histogram[i+1]-1,
-  // but no need to sample if they are the same timeval (aka bin 0 or bin 1).
-  if (bin_end <= bin_start+1)
+  /* Bin edges are monotonically increasing so this is a bug. Handle it. */
+  if (BUG(bin_start >= bin_end)) {
     return bin_start;
-  else
-    return (circpad_delay_t)crypto_rand_uint64_range(bin_start, bin_end);
+  }
+
+  return (circpad_delay_t)crypto_fast_rng_uint64_range(get_thread_fast_rng(),
+                                                       bin_start, bin_end);
 }
 
 /**
@@ -626,7 +758,7 @@ circpad_distribution_sample(circpad_distribution_t dist)
  * greater than the target, and that has tokens remaining.
  */
 static circpad_hist_index_t
-circpad_machine_first_higher_index(const circpad_machine_state_t *mi,
+circpad_machine_first_higher_index(const circpad_machine_runtime_t *mi,
                                    circpad_delay_t target_bin_usec)
 {
   circpad_hist_index_t bin = circpad_histogram_usec_to_bin(mi,
@@ -635,7 +767,7 @@ circpad_machine_first_higher_index(const circpad_machine_state_t *mi,
   /* Don't remove from the infinity bin */
   for (; bin < CIRCPAD_INFINITY_BIN(mi); bin++) {
     if (mi->histogram[bin] &&
-        circpad_histogram_bin_to_usec(mi, bin+1) > target_bin_usec) {
+        histogram_get_bin_upper_bound(mi, bin) >= target_bin_usec) {
       return bin;
     }
   }
@@ -648,7 +780,7 @@ circpad_machine_first_higher_index(const circpad_machine_state_t *mi,
  * <b>target_bin_usec</b>, and that still has tokens remaining.
  */
 static circpad_hist_index_t
-circpad_machine_first_lower_index(const circpad_machine_state_t *mi,
+circpad_machine_first_lower_index(const circpad_machine_runtime_t *mi,
                                   circpad_delay_t target_bin_usec)
 {
   circpad_hist_index_t bin = circpad_histogram_usec_to_bin(mi,
@@ -669,7 +801,7 @@ circpad_machine_first_lower_index(const circpad_machine_state_t *mi,
  * greater than the target.
  */
 STATIC void
-circpad_machine_remove_higher_token(circpad_machine_state_t *mi,
+circpad_machine_remove_higher_token(circpad_machine_runtime_t *mi,
                                     circpad_delay_t target_bin_usec)
 {
   /* We need to remove the token from the first bin
@@ -690,7 +822,7 @@ circpad_machine_remove_higher_token(circpad_machine_state_t *mi,
  * lower than the target.
  */
 STATIC void
-circpad_machine_remove_lower_token(circpad_machine_state_t *mi,
+circpad_machine_remove_lower_token(circpad_machine_runtime_t *mi,
                                    circpad_delay_t target_bin_usec)
 {
   circpad_hist_index_t bin = circpad_machine_first_lower_index(mi,
@@ -719,7 +851,7 @@ circpad_machine_remove_lower_token(circpad_machine_state_t *mi,
  * If it is false, use bin index distance only.
  */
 STATIC void
-circpad_machine_remove_closest_token(circpad_machine_state_t *mi,
+circpad_machine_remove_closest_token(circpad_machine_runtime_t *mi,
                                      circpad_delay_t target_bin_usec,
                                      bool use_usec)
 {
@@ -776,7 +908,7 @@ circpad_machine_remove_closest_token(circpad_machine_state_t *mi,
       bin_to_remove = lower;
     }
     mi->histogram[bin_to_remove]--;
-    log_debug(LD_GENERAL, "Removing token from bin %d", bin_to_remove);
+    log_debug(LD_CIRC, "Removing token from bin %d", bin_to_remove);
     return;
   } else {
     if (current - lower > higher - current) {
@@ -801,7 +933,7 @@ circpad_machine_remove_closest_token(circpad_machine_state_t *mi,
  * If it is empty, do nothing.
  */
 static void
-circpad_machine_remove_exact(circpad_machine_state_t *mi,
+circpad_machine_remove_exact(circpad_machine_runtime_t *mi,
                              circpad_delay_t target_bin_usec)
 {
   circpad_hist_index_t bin = circpad_histogram_usec_to_bin(mi,
@@ -818,7 +950,7 @@ circpad_machine_remove_exact(circpad_machine_state_t *mi,
  * otherwise returns 0.
  */
 static circpad_decision_t
-check_machine_token_supply(circpad_machine_state_t *mi)
+check_machine_token_supply(circpad_machine_runtime_t *mi)
 {
   uint32_t histogram_total_tokens = 0;
 
@@ -829,7 +961,7 @@ check_machine_token_supply(circpad_machine_state_t *mi)
    *
    * We also do not count infinity bin in histogram totals.
    */
-  if (mi->histogram_len && mi->histogram) {
+  if (circpad_is_token_removal_supported(mi)) {
     for (circpad_hist_index_t b = 0; b < CIRCPAD_INFINITY_BIN(mi); b++)
       histogram_total_tokens += mi->histogram[b];
 
@@ -848,22 +980,55 @@ check_machine_token_supply(circpad_machine_state_t *mi)
 }
 
 /**
- * Remove a token from the bin corresponding to the delta since
- * last packet. If that bin is empty, choose a token based on
- * the specified removal strategy in the state machine.
+ * Count that a padding packet was sent.
  *
- * This function also updates and checks rate limit and state
- * limit counters.
- *
- * Returns 1 if we transition states, 0 otherwise.
+ * This updates our state length count, our machine rate limit counts,
+ * and if token removal is used, decrements the histogram.
  */
-STATIC circpad_decision_t
-circpad_machine_remove_token(circpad_machine_state_t *mi)
+static inline void
+circpad_machine_count_padding_sent(circpad_machine_runtime_t *mi)
 {
-  const circpad_state_t *state = NULL;
-  circpad_time_t current_time;
-  circpad_delay_t target_bin_usec;
+  /* If we have a valid state length bound, consider it */
+  if (mi->state_length != CIRCPAD_STATE_LENGTH_INFINITE &&
+      !BUG(mi->state_length <= 0)) {
+    mi->state_length--;
+  }
+
+  /*
+   * Update non-padding counts for rate limiting: We scale at UINT16_MAX
+   * because we only use this for a percentile limit of 2 sig figs, and
+   * space is scare in the machineinfo struct.
+   */
+  mi->padding_sent++;
+  if (mi->padding_sent == UINT16_MAX) {
+    mi->padding_sent /= 2;
+    mi->nonpadding_sent /= 2;
+  }
+
+  circpad_global_padding_sent++;
+
+  /* If we have a mutable histogram, reduce the token count from
+   * the chosen padding bin (this assumes we always send padding
+   * when we intended to). */
+  if (circpad_is_token_removal_supported(mi)) {
+    /* Check array bounds and token count before removing */
+    if (!BUG(mi->chosen_bin >= mi->histogram_len) &&
+        !BUG(mi->histogram[mi->chosen_bin] == 0)) {
+      mi->histogram[mi->chosen_bin]--;
+    }
+  }
+}
 
+/**
+ * Count a nonpadding packet as being sent.
+ *
+ * This function updates our overhead accounting variables, as well
+ * as decrements the state limit packet counter, if the latter was
+ * flagged as applying to non-padding as well.
+ */
+static inline void
+circpad_machine_count_nonpadding_sent(circpad_machine_runtime_t *mi)
+{
   /* Update non-padding counts for rate limiting: We scale at UINT16_MAX
    * because we only use this for a percentile limit of 2 sig figs, and
    * space is scare in the machineinfo struct. */
@@ -873,12 +1038,70 @@ circpad_machine_remove_token(circpad_machine_state_t *mi)
     mi->nonpadding_sent /= 2;
   }
 
+  /* Update any state packet length limits that apply */
+  circpad_machine_update_state_length_for_nonpadding(mi);
+
+  /* Remove a token from the histogram, if applicable */
+  circpad_machine_remove_token(mi);
+}
+
+/**
+ * Decrement the state length counter for a non-padding packet.
+ *
+ * Only updates the state length if we're using that feature, we
+ * have a state, and the machine wants to count non-padding packets
+ * towards the state length.
+ */
+static inline void
+circpad_machine_update_state_length_for_nonpadding(
+        circpad_machine_runtime_t *mi)
+{
+  const circpad_state_t *state = NULL;
+
+  if (mi->state_length == CIRCPAD_STATE_LENGTH_INFINITE)
+    return;
+
+  state = circpad_machine_current_state(mi);
+
+  /* If we are not in a padding state (like start or end), we're done */
+  if (!state)
+    return;
+
+  /* If we're enforcing a state length on non-padding packets,
+   * decrement it */
+  if (state->length_includes_nonpadding &&
+      mi->state_length > 0) {
+    mi->state_length--;
+  }
+}
+
+/**
+ * When a non-padding packet arrives, remove a token from the bin
+ * corresponding to the delta since last sent packet. If that bin
+ * is empty, choose a token based on the specified removal strategy
+ * in the state machine.
+ */
+STATIC void
+circpad_machine_remove_token(circpad_machine_runtime_t *mi)
+{
+  const circpad_state_t *state = NULL;
+  circpad_time_t current_time;
+  circpad_delay_t target_bin_usec;
+
   /* Dont remove any tokens if there was no padding scheduled */
   if (!mi->padding_scheduled_at_usec) {
-    return CIRCPAD_STATE_UNCHANGED;
+    return;
   }
 
   state = circpad_machine_current_state(mi);
+
+  /* If we are not in a padding state (like start or end), we're done */
+  if (!state)
+    return;
+  /* Don't remove any tokens if we're not doing token removal */
+  if (state->token_removal == CIRCPAD_TOKEN_REMOVAL_NONE)
+    return;
+
   current_time = monotime_absolute_usec();
 
   /* If we have scheduled padding some time in the future, we want to see what
@@ -895,22 +1118,8 @@ circpad_machine_remove_token(circpad_machine_state_t *mi)
     timer_disable(mi->padding_timer);
   }
 
-  /* If we are not in a padding state (like start or end), we're done */
-  if (!state)
-    return CIRCPAD_STATE_UNCHANGED;
-
-  /* If we're enforcing a state length on non-padding packets,
-   * decrement it */
-  if (mi->state_length != CIRCPAD_STATE_LENGTH_INFINITE &&
-      state->length_includes_nonpadding &&
-      mi->state_length > 0) {
-    mi->state_length--;
-  }
-
   /* Perform the specified token removal strategy */
   switch (state->token_removal) {
-    case CIRCPAD_TOKEN_REMOVAL_NONE:
-      break;
     case CIRCPAD_TOKEN_REMOVAL_CLOSEST_USEC:
       circpad_machine_remove_closest_token(mi, target_bin_usec, 1);
       break;
@@ -926,10 +1135,13 @@ circpad_machine_remove_token(circpad_machine_state_t *mi)
     case CIRCPAD_TOKEN_REMOVAL_EXACT:
       circpad_machine_remove_exact(mi, target_bin_usec);
       break;
+    case CIRCPAD_TOKEN_REMOVAL_NONE:
+    default:
+      tor_assert_nonfatal_unreached();
+      log_warn(LD_BUG, "Circpad: Unknown token removal strategy %d",
+               state->token_removal);
+      break;
   }
-
-  /* Check our token and state length limits */
-  return check_machine_token_supply(mi);
 }
 
 /**
@@ -985,63 +1197,41 @@ circpad_send_command_to_hop,(origin_circuit_t *circ, uint8_t hopnum,
  * CIRCPAD_STATE_CHANGED. Otherwise return CIRCPAD_STATE_UNCHANGED.
  */
 circpad_decision_t
-circpad_send_padding_cell_for_callback(circpad_machine_state_t *mi)
+circpad_send_padding_cell_for_callback(circpad_machine_runtime_t *mi)
 {
   circuit_t *circ = mi->on_circ;
   int machine_idx = mi->machine_index;
   mi->padding_scheduled_at_usec = 0;
   circpad_statenum_t state = mi->current_state;
 
-  // Make sure circuit didn't close on us
+  /* Make sure circuit didn't close on us */
   if (mi->on_circ->marked_for_close) {
     log_fn(LOG_INFO,LD_CIRC,
-           "Padding callback on a circuit marked for close. Ignoring.");
+           "Padding callback on circuit marked for close (%u). Ignoring.",
+         CIRCUIT_IS_ORIGIN(mi->on_circ) ?
+         TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier : 0);
     return CIRCPAD_STATE_CHANGED;
   }
 
-  /* If it's a histogram, reduce the token count */
-  if (mi->histogram && mi->histogram_len) {
-    /* Basic sanity check on the histogram before removing anything */
-    if (BUG(mi->chosen_bin >= mi->histogram_len) ||
-        BUG(mi->histogram[mi->chosen_bin] == 0)) {
-      return CIRCPAD_STATE_CHANGED;
-    }
-
-    mi->histogram[mi->chosen_bin]--;
-  }
-
-  /* If we have a valid state length bound, consider it */
-  if (mi->state_length != CIRCPAD_STATE_LENGTH_INFINITE &&
-      !BUG(mi->state_length <= 0)) {
-    mi->state_length--;
-  }
-
-  /*
-   * Update non-padding counts for rate limiting: We scale at UINT16_MAX
-   * because we only use this for a percentile limit of 2 sig figs, and
-   * space is scare in the machineinfo struct.
-   */
-  mi->padding_sent++;
-  if (mi->padding_sent == UINT16_MAX) {
-    mi->padding_sent /= 2;
-    mi->nonpadding_sent /= 2;
-  }
-  circpad_global_padding_sent++;
+  circpad_machine_count_padding_sent(mi);
 
   if (CIRCUIT_IS_ORIGIN(mi->on_circ)) {
     circpad_send_command_to_hop(TO_ORIGIN_CIRCUIT(mi->on_circ),
                                 CIRCPAD_GET_MACHINE(mi)->target_hopnum,
                                 RELAY_COMMAND_DROP, NULL, 0);
-    log_fn(LOG_INFO,LD_CIRC, "Callback: Sending padding to origin circuit %u.",
-           TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier);
+    log_info(LD_CIRC, "Callback: Sending padding to origin circuit %u"
+             " (%d) [length: %"PRIu64"]",
+             TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier,
+             mi->on_circ->purpose, mi->state_length);
   } else {
     // If we're a non-origin circ, we can just send from here as if we're the
     // edge.
     if (TO_OR_CIRCUIT(circ)->p_chan_cells.n <= circpad_max_circ_queued_cells) {
-      log_fn(LOG_INFO,LD_CIRC,
-             "Callback: Sending padding to non-origin circuit.");
+      log_info(LD_CIRC, "Callback: Sending padding to circuit (%d)"
+               " [length: %"PRIu64"]", mi->on_circ->purpose, mi->state_length);
       relay_send_command_from_edge(0, mi->on_circ, RELAY_COMMAND_DROP, NULL,
                                    0, NULL);
+      rep_hist_padding_count_write(PADDING_TYPE_DROP);
     } else {
       static ratelim_t cell_lim = RATELIM_INIT(600);
       log_fn_ratelim(&cell_lim,LOG_NOTICE,LD_CIRC,
@@ -1050,7 +1240,6 @@ circpad_send_padding_cell_for_callback(circpad_machine_state_t *mi)
     }
   }
 
-  rep_hist_padding_count_write(PADDING_TYPE_DROP);
   /* This is a padding cell sent from the client or from the middle node,
    * (because it's invoked from circuitpadding.c) */
   circpad_cell_event_padding_sent(circ);
@@ -1071,7 +1260,7 @@ circpad_send_padding_cell_for_callback(circpad_machine_state_t *mi)
 /**
  * Tor-timer compatible callback that tells us to send a padding cell.
  *
- * Timers are associated with circpad_machine_state_t's. When the machineinfo
+ * Timers are associated with circpad_machine_runtime_t's. When the machineinfo
  * is freed on a circuit, the timers are cancelled. Since the lifetime
  * of machineinfo is always longer than the timers, handles are not
  * needed.
@@ -1080,7 +1269,7 @@ static void
 circpad_send_padding_callback(tor_timer_t *timer, void *args,
                               const struct monotime_t *time)
 {
-  circpad_machine_state_t *mi = ((circpad_machine_state_t*)args);
+  circpad_machine_runtime_t *mi = ((circpad_machine_runtime_t*)args);
   (void)timer; (void)time;
 
   if (mi && mi->on_circ) {
@@ -1103,6 +1292,14 @@ circpad_send_padding_callback(tor_timer_t *timer, void *args,
 void
 circpad_new_consensus_params(const networkstatus_t *ns)
 {
+  circpad_padding_disabled =
+      networkstatus_get_param(ns, "circpad_padding_disabled",
+         0, 0, 1);
+
+  circpad_padding_reduced =
+      networkstatus_get_param(ns, "circpad_padding_reduced",
+         0, 0, 1);
+
   circpad_global_allowed_cells =
       networkstatus_get_param(ns, "circpad_global_allowed_cells",
          0, 0, UINT16_MAX-1);
@@ -1117,6 +1314,24 @@ circpad_new_consensus_params(const networkstatus_t *ns)
 }
 
 /**
+ * Return true if padding is allowed by torrc and consensus.
+ */
+static bool
+circpad_is_padding_allowed(void)
+{
+  /* If padding has been disabled in the consensus, don't send any more
+   * padding. Technically the machine should be shut down when the next
+   * machine condition check happens, but machine checks only happen on
+   * certain circuit events, and if padding is disabled due to some
+   * network overload or DoS condition, we really want to stop ASAP. */
+  if (circpad_padding_disabled || !get_options()->CircuitPadding) {
+    return 0;
+  }
+
+  return 1;
+}
+
+/**
  * Check this machine against its padding limits, as well as global
  * consensus limits.
  *
@@ -1130,14 +1345,14 @@ circpad_new_consensus_params(const networkstatus_t *ns)
  * Returns 1 if limits are set and we've hit them. Otherwise returns 0.
  */
 STATIC bool
-circpad_machine_reached_padding_limit(circpad_machine_state_t *mi)
+circpad_machine_reached_padding_limit(circpad_machine_runtime_t *mi)
 {
   const circpad_machine_spec_t *machine = CIRCPAD_GET_MACHINE(mi);
 
   /* If machine_padding_pct is non-zero, and we've sent more
    * than the allowed count of padding cells, then check our
    * percent limits for this machine. */
-   if (machine->max_padding_percent &&
+  if (machine->max_padding_percent &&
       mi->padding_sent >= machine->allowed_padding_count) {
     uint32_t total_cells = mi->padding_sent + mi->nonpadding_sent;
 
@@ -1178,16 +1393,36 @@ circpad_machine_reached_padding_limit(circpad_machine_state_t *mi)
  * 0 otherwise.
  */
 MOCK_IMPL(circpad_decision_t,
-circpad_machine_schedule_padding,(circpad_machine_state_t *mi))
+circpad_machine_schedule_padding,(circpad_machine_runtime_t *mi))
 {
   circpad_delay_t in_usec = 0;
   struct timeval timeout;
   tor_assert(mi);
 
+  /* Don't schedule padding if it is disabled */
+  if (!circpad_is_padding_allowed()) {
+    static ratelim_t padding_lim = RATELIM_INIT(600);
+    log_fn_ratelim(&padding_lim,LOG_INFO,LD_CIRC,
+         "Padding has been disabled, but machine still on circuit %"PRIu64
+         ", %d",
+         mi->on_circ->n_chan ? mi->on_circ->n_chan->global_identifier : 0,
+         mi->on_circ->n_circ_id);
+
+    return CIRCPAD_STATE_UNCHANGED;
+  }
+
+  /* Don't schedule padding if we are currently in dormant mode. */
+  if (!is_participating_on_network()) {
+    log_info(LD_CIRC, "Not scheduling padding because we are dormant.");
+    return CIRCPAD_STATE_UNCHANGED;
+  }
+
   // Don't pad in end (but  also don't cancel any previously
   // scheduled padding either).
   if (mi->current_state == CIRCPAD_STATE_END) {
-    log_fn(LOG_INFO, LD_CIRC, "Padding end state");
+    log_fn(LOG_INFO, LD_CIRC, "Padding end state on circuit %u",
+         CIRCUIT_IS_ORIGIN(mi->on_circ) ?
+           TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier : 0);
     return CIRCPAD_STATE_UNCHANGED;
   }
 
@@ -1198,7 +1433,8 @@ circpad_machine_schedule_padding,(circpad_machine_state_t *mi))
            "Padding machine has reached padding limit on circuit %u",
              TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier);
     } else {
-      log_fn(LOG_INFO, LD_CIRC,
+      static ratelim_t padding_lim = RATELIM_INIT(600);
+      log_fn_ratelim(&padding_lim,LOG_INFO,LD_CIRC,
            "Padding machine has reached padding limit on circuit %"PRIu64
            ", %d",
            mi->on_circ->n_chan ? mi->on_circ->n_chan->global_identifier : 0,
@@ -1215,8 +1451,20 @@ circpad_machine_schedule_padding,(circpad_machine_state_t *mi))
 
   /* in_usec = in microseconds */
   in_usec = circpad_machine_sample_delay(mi);
-  mi->padding_scheduled_at_usec = monotime_absolute_usec();
-  log_fn(LOG_INFO,LD_CIRC,"\tPadding in %u usec", in_usec);
+  /* If we're using token removal, we need to know when the padding
+   * was scheduled at, so we can remove the appropriate token if
+   * a non-padding cell is sent before the padding timer expires.
+   *
+   * However, since monotime is unpredictably expensive, let's avoid
+   * using it for machines that don't need token removal. */
+  if (circpad_is_token_removal_supported(mi)) {
+    mi->padding_scheduled_at_usec = monotime_absolute_usec();
+  } else {
+    mi->padding_scheduled_at_usec = 1;
+  }
+  log_fn(LOG_INFO,LD_CIRC,"\tPadding in %u usec on circuit %u", in_usec,
+       CIRCUIT_IS_ORIGIN(mi->on_circ) ?
+           TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier : 0);
 
   // Don't schedule if we have infinite delay.
   if (in_usec == CIRCPAD_DELAY_INFINITE) {
@@ -1240,7 +1488,9 @@ circpad_machine_schedule_padding,(circpad_machine_state_t *mi))
   timeout.tv_sec = in_usec/TOR_USEC_PER_SEC;
   timeout.tv_usec = (in_usec%TOR_USEC_PER_SEC);
 
-  log_fn(LOG_INFO, LD_CIRC, "\tPadding in %u sec, %u usec",
+  log_fn(LOG_INFO, LD_CIRC, "\tPadding circuit %u in %u sec, %u usec",
+     CIRCUIT_IS_ORIGIN(mi->on_circ) ?
+           TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier : 0,
           (unsigned)timeout.tv_sec, (unsigned)timeout.tv_usec);
 
   if (mi->padding_timer) {
@@ -1268,9 +1518,15 @@ circpad_machine_schedule_padding,(circpad_machine_state_t *mi))
  * not access it.
  */
 static void
-circpad_machine_spec_transitioned_to_end(circpad_machine_state_t *mi)
+circpad_machine_spec_transitioned_to_end(circpad_machine_runtime_t *mi)
 {
   const circpad_machine_spec_t *machine = CIRCPAD_GET_MACHINE(mi);
+  circuit_t *on_circ = mi->on_circ;
+
+  log_fn(LOG_INFO,LD_CIRC, "Padding machine in end state on circuit %u (%d)",
+         CIRCUIT_IS_ORIGIN(on_circ) ?
+         TO_ORIGIN_CIRCUIT(on_circ)->global_identifier : 0,
+         on_circ->purpose);
 
   /*
    * We allow machines to shut down and delete themselves as opposed
@@ -1286,7 +1542,6 @@ circpad_machine_spec_transitioned_to_end(circpad_machine_state_t *mi)
    * here does.
    */
   if (machine->should_negotiate_end) {
-    circuit_t *on_circ = mi->on_circ;
     if (machine->is_origin_side) {
       /* We free the machine info here so that we can be replaced
        * by a different machine. But we must leave the padding_machine
@@ -1318,7 +1573,7 @@ circpad_machine_spec_transitioned_to_end(circpad_machine_state_t *mi)
  * Returns 1 if we transition states, 0 otherwise.
  */
 MOCK_IMPL(circpad_decision_t,
-circpad_machine_spec_transition,(circpad_machine_state_t *mi,
+circpad_machine_spec_transition,(circpad_machine_runtime_t *mi,
                             circpad_event_t event))
 {
   const circpad_state_t *state =
@@ -1352,9 +1607,10 @@ circpad_machine_spec_transition,(circpad_machine_state_t *mi,
      * a transition to itself. All non-specified events are ignored.
      */
     log_fn(LOG_INFO, LD_CIRC,
-           "Circpad machine %d transitioning from %s to %s",
-            mi->machine_index, circpad_state_to_string(mi->current_state),
-            circpad_state_to_string(s));
+           "Circuit %u circpad machine %d transitioning from %u to %u",
+             CIRCUIT_IS_ORIGIN(mi->on_circ) ?
+             TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier : 0,
+           mi->machine_index, mi->current_state, s);
 
     /* If this is not the same state, switch and init tokens,
      * otherwise just reschedule padding. */
@@ -1399,7 +1655,7 @@ circpad_machine_spec_transition,(circpad_machine_state_t *mi,
  */
 static void
 circpad_estimate_circ_rtt_on_received(circuit_t *circ,
-                                      circpad_machine_state_t *mi)
+                                      circpad_machine_runtime_t *mi)
 {
   /* Origin circuits don't estimate RTT. They could do it easily enough,
    * but they have no reason to use it in any delay calculations. */
@@ -1428,10 +1684,29 @@ circpad_estimate_circ_rtt_on_received(circuit_t *circ,
            ", %d) after two back to back packets. Current RTT: %d",
            circ->n_chan ?  circ->n_chan->global_identifier : 0,
            circ->n_circ_id, mi->rtt_estimate_usec);
-       mi->stop_rtt_update = 1;
+      mi->stop_rtt_update = 1;
+
+      if (!mi->rtt_estimate_usec) {
+        static ratelim_t rtt_lim = RATELIM_INIT(600);
+        log_fn_ratelim(&rtt_lim,LOG_NOTICE,LD_BUG,
+          "Circuit got two cells back to back before estimating RTT.");
+      }
     }
   } else {
-    mi->last_received_time_usec = monotime_absolute_usec();
+    const circpad_state_t *state = circpad_machine_current_state(mi);
+    if (BUG(!state)) {
+      return;
+    }
+
+    /* Since monotime is unpredictably expensive, only update this field
+     * if rtt estimates are needed. Otherwise, stop the rtt update. */
+    if (state->use_rtt_estimate) {
+      mi->last_received_time_usec = monotime_absolute_usec();
+    } else {
+      /* Let's fast-path future decisions not to update rtt if the
+       * feature is not in use. */
+      mi->stop_rtt_update = 1;
+    }
   }
 }
 
@@ -1446,7 +1721,7 @@ circpad_estimate_circ_rtt_on_received(circuit_t *circ,
  */
 static void
 circpad_estimate_circ_rtt_on_send(circuit_t *circ,
-                                  circpad_machine_state_t *mi)
+                                  circpad_machine_runtime_t *mi)
 {
   /* Origin circuits don't estimate RTT. They could do it easily enough,
    * but they have no reason to use it in any delay calculations. */
@@ -1488,12 +1763,12 @@ circpad_estimate_circ_rtt_on_send(circuit_t *circ,
      * to back. Stop estimating RTT in this case. Note that we only
      * stop RTT update if the circuit is opened, to allow for RTT estimates
      * of var cells during circ setup. */
-    mi->stop_rtt_update = 1;
-
-    if (!mi->rtt_estimate_usec) {
-      log_fn(LOG_NOTICE, LD_CIRC,
-             "Got two cells back to back on a circuit before estimating RTT.");
+    if (!mi->rtt_estimate_usec && !mi->stop_rtt_update) {
+      static ratelim_t rtt_lim = RATELIM_INIT(600);
+      log_fn_ratelim(&rtt_lim,LOG_NOTICE,LD_BUG,
+        "Circuit sent two cells back to back before estimating RTT.");
     }
+    mi->stop_rtt_update = 1;
   }
 }
 
@@ -1513,12 +1788,17 @@ circpad_cell_event_nonpadding_sent(circuit_t *on_circ)
 
   /* If there are no machines then this loop should not iterate */
   FOR_EACH_ACTIVE_CIRCUIT_MACHINE_BEGIN(i, on_circ) {
-    /* First, update any RTT estimate */
+    /* First, update any timestamps */
+    on_circ->padding_info[i]->last_cell_time_sec = approx_time();
     circpad_estimate_circ_rtt_on_send(on_circ, on_circ->padding_info[i]);
 
-    /* Remove a token: this is the idea of adaptive padding, since we have an
-     * ideal distribution that we want our distribution to look like. */
-    if (!circpad_machine_remove_token(on_circ->padding_info[i])) {
+    /* Then, do accounting */
+    circpad_machine_count_nonpadding_sent(on_circ->padding_info[i]);
+
+    /* Check to see if we've run out of tokens for this state already,
+     * and if not, check for other state transitions */
+    if (check_machine_token_supply(on_circ->padding_info[i])
+        == CIRCPAD_STATE_UNCHANGED) {
       /* If removing a token did not cause a transition, check if
        * non-padding sent event should */
       circpad_machine_spec_transition(on_circ->padding_info[i],
@@ -1539,7 +1819,8 @@ void
 circpad_cell_event_nonpadding_received(circuit_t *on_circ)
 {
   FOR_EACH_ACTIVE_CIRCUIT_MACHINE_BEGIN(i, on_circ) {
-    /* First, update any RTT estimate */
+    /* First, update any timestamps */
+    on_circ->padding_info[i]->last_cell_time_sec = approx_time();
     circpad_estimate_circ_rtt_on_received(on_circ, on_circ->padding_info[i]);
 
     circpad_machine_spec_transition(on_circ->padding_info[i],
@@ -1559,8 +1840,17 @@ void
 circpad_cell_event_padding_sent(circuit_t *on_circ)
 {
   FOR_EACH_ACTIVE_CIRCUIT_MACHINE_BEGIN(i, on_circ) {
-    circpad_machine_spec_transition(on_circ->padding_info[i],
+    /* Check to see if we've run out of tokens for this state already,
+     * and if not, check for other state transitions */
+    if (check_machine_token_supply(on_circ->padding_info[i])
+        == CIRCPAD_STATE_UNCHANGED) {
+      /* If removing a token did not cause a transition, check if
+       * non-padding sent event should */
+
+      on_circ->padding_info[i]->last_cell_time_sec = approx_time();
+      circpad_machine_spec_transition(on_circ->padding_info[i],
                              CIRCPAD_EVENT_PADDING_SENT);
+    }
   } FOR_EACH_ACTIVE_CIRCUIT_MACHINE_END;
 }
 
@@ -1577,6 +1867,7 @@ circpad_cell_event_padding_received(circuit_t *on_circ)
 {
   /* identical to padding sent */
   FOR_EACH_ACTIVE_CIRCUIT_MACHINE_BEGIN(i, on_circ) {
+    on_circ->padding_info[i]->last_cell_time_sec = approx_time();
     circpad_machine_spec_transition(on_circ->padding_info[i],
                               CIRCPAD_EVENT_PADDING_RECV);
   } FOR_EACH_ACTIVE_CIRCUIT_MACHINE_END;
@@ -1592,7 +1883,7 @@ circpad_cell_event_padding_received(circuit_t *on_circ)
  * Return 1 if we decide to transition, 0 otherwise.
  */
 circpad_decision_t
-circpad_internal_event_infinity(circpad_machine_state_t *mi)
+circpad_internal_event_infinity(circpad_machine_runtime_t *mi)
 {
   return circpad_machine_spec_transition(mi, CIRCPAD_EVENT_INFINITY);
 }
@@ -1606,7 +1897,7 @@ circpad_internal_event_infinity(circpad_machine_state_t *mi)
  * Return 1 if we decide to transition, 0 otherwise.
  */
 circpad_decision_t
-circpad_internal_event_bins_empty(circpad_machine_state_t *mi)
+circpad_internal_event_bins_empty(circpad_machine_runtime_t *mi)
 {
   if (circpad_machine_spec_transition(mi, CIRCPAD_EVENT_BINS_EMPTY)
       == CIRCPAD_STATE_CHANGED) {
@@ -1625,7 +1916,7 @@ circpad_internal_event_bins_empty(circpad_machine_state_t *mi)
  * Return 1 if we decide to transition, 0 otherwise.
  */
 circpad_decision_t
-circpad_internal_event_state_length_up(circpad_machine_state_t *mi)
+circpad_internal_event_state_length_up(circpad_machine_runtime_t *mi)
 {
   return circpad_machine_spec_transition(mi, CIRCPAD_EVENT_LENGTH_COUNT);
 }
@@ -1637,6 +1928,19 @@ static inline bool
 circpad_machine_conditions_met(origin_circuit_t *circ,
                                const circpad_machine_spec_t *machine)
 {
+  /* If padding is disabled, no machines should match/apply. This has
+   * the effect of shutting down all machines, and not adding any more. */
+  if (circpad_padding_disabled || !get_options()->CircuitPadding)
+    return 0;
+
+  /* If the consensus or our torrc has selected reduced connection padding,
+   * then only allow this machine if it is flagged as acceptable under
+   * reduced padding conditions */
+  if (circpad_padding_reduced || get_options()->ReducedCircuitPadding) {
+    if (!machine->conditions.reduced_padding_ok)
+      return 0;
+  }
+
   if (!(circpad_circ_purpose_to_mask(TO_CIRCUIT(circ)->purpose)
       & machine->conditions.purpose_mask))
     return 0;
@@ -1700,7 +2004,6 @@ circpad_circuit_state(origin_circuit_t *circ)
  * Convert a normal circuit purpose into a bitmask that we can
  * use for determining matching circuits.
  */
-static inline
 circpad_purpose_mask_t
 circpad_circ_purpose_to_mask(uint8_t circ_purpose)
 {
@@ -1743,7 +2046,8 @@ circpad_shutdown_old_machines(origin_circuit_t *on_circ)
 }
 
 /**
- * Negotiate new machines that would apply to this circuit.
+ * Negotiate new machines that would apply to this circuit, given the machines
+ * inside <b>machines_sl</b>.
  *
  * This function checks to see if we have any free machine indexes,
  * and for each free machine index, it initializes the most recently
@@ -1751,14 +2055,15 @@ circpad_shutdown_old_machines(origin_circuit_t *on_circ)
  * index and circuit conditions, and negotiates it with the appropriate
  * middle relay.
  */
-static void
-circpad_add_matching_machines(origin_circuit_t *on_circ)
+STATIC void
+circpad_add_matching_machines(origin_circuit_t *on_circ,
+                              smartlist_t *machines_sl)
 {
   circuit_t *circ = TO_CIRCUIT(on_circ);
 
 #ifdef TOR_UNIT_TESTS
   /* Tests don't have to init our padding machines */
-  if (!origin_padding_machines)
+  if (!machines_sl)
     return;
 #endif
 
@@ -1775,7 +2080,7 @@ circpad_add_matching_machines(origin_circuit_t *on_circ)
     /* We have a free machine index. Check the origin padding
      * machines in reverse order, so that more recently added
      * machines take priority over older ones. */
-    SMARTLIST_FOREACH_REVERSE_BEGIN(origin_padding_machines,
+    SMARTLIST_FOREACH_REVERSE_BEGIN(machines_sl,
                                     circpad_machine_spec_t *,
                                     machine) {
       /* Machine definitions have a specific target machine index.
@@ -1803,6 +2108,10 @@ circpad_add_matching_machines(origin_circuit_t *on_circ)
         if (circpad_negotiate_padding(on_circ, machine->machine_num,
                                   machine->target_hopnum,
                                   CIRCPAD_COMMAND_START) < 0) {
+          log_info(LD_CIRC,
+                   "Padding not negotiated. Cleaning machine from circuit %u",
+             CIRCUIT_IS_ORIGIN(circ) ?
+             TO_ORIGIN_CIRCUIT(circ)->global_identifier : 0);
           circpad_circuit_machineinfo_free_idx(circ, i);
           circ->padding_machine[i] = NULL;
           on_circ->padding_negotiation_failed = 1;
@@ -1826,7 +2135,7 @@ circpad_machine_event_circ_added_hop(origin_circuit_t *on_circ)
 {
   /* Since our padding conditions do not specify a max_hops,
    * all we can do is add machines here */
-  circpad_add_matching_machines(on_circ);
+  circpad_add_matching_machines(on_circ, origin_padding_machines);
 }
 
 /**
@@ -1839,7 +2148,7 @@ void
 circpad_machine_event_circ_built(origin_circuit_t *circ)
 {
   circpad_shutdown_old_machines(circ);
-  circpad_add_matching_machines(circ);
+  circpad_add_matching_machines(circ, origin_padding_machines);
 }
 
 /**
@@ -1852,7 +2161,7 @@ void
 circpad_machine_event_circ_purpose_changed(origin_circuit_t *circ)
 {
   circpad_shutdown_old_machines(circ);
-  circpad_add_matching_machines(circ);
+  circpad_add_matching_machines(circ, origin_padding_machines);
 }
 
 /**
@@ -1866,7 +2175,7 @@ void
 circpad_machine_event_circ_has_no_relay_early(origin_circuit_t *circ)
 {
   circpad_shutdown_old_machines(circ);
-  circpad_add_matching_machines(circ);
+  circpad_add_matching_machines(circ, origin_padding_machines);
 }
 
 /**
@@ -1881,7 +2190,7 @@ void
 circpad_machine_event_circ_has_streams(origin_circuit_t *circ)
 {
   circpad_shutdown_old_machines(circ);
-  circpad_add_matching_machines(circ);
+  circpad_add_matching_machines(circ, origin_padding_machines);
 }
 
 /**
@@ -1896,7 +2205,7 @@ void
 circpad_machine_event_circ_has_no_streams(origin_circuit_t *circ)
 {
   circpad_shutdown_old_machines(circ);
-  circpad_add_matching_machines(circ);
+  circpad_add_matching_machines(circ, origin_padding_machines);
 }
 
 /**
@@ -1977,13 +2286,6 @@ circpad_deliver_recognized_relay_cell_events(circuit_t *circ,
                                              uint8_t relay_command,
                                              crypt_path_t *layer_hint)
 {
-  /* Padding negotiate cells are ignored by the state machines
-   * for simplicity. */
-  if (relay_command == RELAY_COMMAND_PADDING_NEGOTIATE ||
-      relay_command == RELAY_COMMAND_PADDING_NEGOTIATED) {
-    return;
-  }
-
   if (relay_command == RELAY_COMMAND_DROP) {
     rep_hist_padding_count_read(PADDING_TYPE_DROP);
 
@@ -2020,16 +2322,12 @@ void
 circpad_deliver_sent_relay_cell_events(circuit_t *circ,
                                        uint8_t relay_command)
 {
-  /* Padding negotiate cells are ignored by the state machines
-   * for simplicity. */
-  if (relay_command == RELAY_COMMAND_PADDING_NEGOTIATE ||
-      relay_command == RELAY_COMMAND_PADDING_NEGOTIATED) {
-    return;
-  }
-
   /* RELAY_COMMAND_DROP is the multi-hop (aka circuit-level) padding cell in
    * tor. (CELL_PADDING is a channel-level padding cell, which is not relayed
-   * or processed here) */
+   * or processed here).
+   *
+   * We do generate events for PADDING_NEGOTIATE and PADDING_NEGOTIATED cells.
+   */
   if (relay_command == RELAY_COMMAND_DROP) {
     /* Optimization: The event for RELAY_COMMAND_DROP is sent directly
      * from circpad_send_padding_cell_for_callback(). This is to avoid
@@ -2087,25 +2385,112 @@ circpad_setup_machine_on_circ(circuit_t *on_circ,
                       == NULL);
   tor_assert_nonfatal(on_circ->padding_info[machine->machine_index] == NULL);
 
+  /* Log message */
+  if (CIRCUIT_IS_ORIGIN(on_circ)) {
+    log_info(LD_CIRC, "Registering machine %s to origin circ %u (%d)",
+             machine->name,
+             TO_ORIGIN_CIRCUIT(on_circ)->global_identifier, on_circ->purpose);
+  } else {
+    log_info(LD_CIRC, "Registering machine %s to non-origin circ (%d)",
+             machine->name, on_circ->purpose);
+  }
+
   on_circ->padding_info[machine->machine_index] =
       circpad_circuit_machineinfo_new(on_circ, machine->machine_index);
   on_circ->padding_machine[machine->machine_index] = machine;
 }
 
-/* These padding machines are only used for tests pending #28634. */
+/** Validate a single state of a padding machine */
+static bool
+padding_machine_state_is_valid(const circpad_state_t *state)
+{
+  int b;
+  uint32_t tokens_count = 0;
+  circpad_delay_t prev_bin_edge = 0;
+
+  /* We only validate histograms */
+  if (!state->histogram_len) {
+    return true;
+  }
+
+  /* We need at least two bins in a histogram */
+  if (state->histogram_len < 2) {
+    log_warn(LD_CIRC, "You can't have a histogram with less than 2 bins");
+    return false;
+  }
+
+  /* For each machine state, if it's a histogram, make sure all the
+   * histogram edges are well defined (i.e. are strictly monotonic). */
+  for (b = 0 ; b < state->histogram_len ; b++) {
+    /* Check that histogram edges are strictly increasing. Ignore the first
+     * edge since it can be zero. */
+    if (prev_bin_edge >= state->histogram_edges[b] && b > 0) {
+      log_warn(LD_CIRC, "Histogram edges are not increasing [%u/%u]",
+               prev_bin_edge, state->histogram_edges[b]);
+      return false;
+    }
+
+    prev_bin_edge = state->histogram_edges[b];
+
+    /* Also count the number of tokens as we go through the histogram states */
+    tokens_count += state->histogram[b];
+  }
+  /* Verify that the total number of tokens is correct */
+  if (tokens_count != state->histogram_total_tokens) {
+    log_warn(LD_CIRC, "Histogram token count is wrong [%u/%u]",
+             tokens_count, state->histogram_total_tokens);
+    return false;
+  }
+
+  return true;
+}
+
+/** Basic validation of padding machine */
+static bool
+padding_machine_is_valid(const circpad_machine_spec_t *machine)
+{
+  int i;
+
+  /* Validate the histograms of the padding machine */
+  for (i = 0 ; i < machine->num_states ; i++) {
+    if (!padding_machine_state_is_valid(&machine->states[i])) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+/* Validate and register <b>machine</b> into <b>machine_list</b>. If
+ * <b>machine_list</b> is NULL, then just validate. */
+void
+circpad_register_padding_machine(circpad_machine_spec_t *machine,
+                                 smartlist_t *machine_list)
+{
+  if (!padding_machine_is_valid(machine)) {
+    log_warn(LD_CIRC, "Machine #%u is invalid. Ignoring.",
+             machine->machine_num);
+    return;
+  }
+
+  if (machine_list) {
+    smartlist_add(machine_list, machine);
+  }
+}
+
 #ifdef TOR_UNIT_TESTS
+/* These padding machines are only used for tests pending #28634. */
 static void
 circpad_circ_client_machine_init(void)
 {
   circpad_machine_spec_t *circ_client_machine
       = tor_malloc_zero(sizeof(circpad_machine_spec_t));
 
-  // XXX: Better conditions for merge.. Or disable this machine in
-  // merge?
   circ_client_machine->conditions.min_hops = 2;
   circ_client_machine->conditions.state_mask =
       CIRCPAD_CIRC_BUILDING|CIRCPAD_CIRC_OPENED|CIRCPAD_CIRC_HAS_RELAY_EARLY;
   circ_client_machine->conditions.purpose_mask = CIRCPAD_PURPOSE_ALL;
+  circ_client_machine->conditions.reduced_padding_ok = 1;
 
   circ_client_machine->target_hopnum = 2;
   circ_client_machine->is_origin_side = 1;
@@ -2133,19 +2518,21 @@ circpad_circ_client_machine_init(void)
   circ_client_machine->states[CIRCPAD_STATE_BURST].token_removal =
       CIRCPAD_TOKEN_REMOVAL_CLOSEST;
 
-  // FIXME: Tune this histogram
   circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_len = 2;
-  circ_client_machine->states[CIRCPAD_STATE_BURST].start_usec = 500;
-  circ_client_machine->states[CIRCPAD_STATE_BURST].range_usec = 1000000;
+  circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_edges[0]= 500;
+  circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_edges[1]= 1000000;
+
   /* We have 5 tokens in the histogram, which means that all circuits will look
    * like they have 7 hops (since we start this machine after the second hop,
    * and tokens are decremented for any valid hops, and fake extends are
    * used after that -- 2+5==7). */
   circ_client_machine->states[CIRCPAD_STATE_BURST].histogram[0] = 5;
+
   circ_client_machine->states[CIRCPAD_STATE_BURST].histogram_total_tokens = 5;
 
   circ_client_machine->machine_num = smartlist_len(origin_padding_machines);
-  smartlist_add(origin_padding_machines, circ_client_machine);
+  circpad_register_padding_machine(circ_client_machine,
+                                   origin_padding_machines);
 }
 
 static void
@@ -2192,8 +2579,9 @@ circpad_circ_responder_machine_init(void)
   circ_responder_machine->states[CIRCPAD_STATE_BURST].use_rtt_estimate = 1;
   /* The histogram is 2 bins: an empty one, and infinity */
   circ_responder_machine->states[CIRCPAD_STATE_BURST].histogram_len = 2;
-  circ_responder_machine->states[CIRCPAD_STATE_BURST].start_usec = 5000;
-  circ_responder_machine->states[CIRCPAD_STATE_BURST].range_usec = 1000000;
+  circ_responder_machine->states[CIRCPAD_STATE_BURST].histogram_edges[0]= 500;
+  circ_responder_machine->states[CIRCPAD_STATE_BURST].histogram_edges[1] =
+    1000000;
   /* During burst state we wait forever for padding to arrive.
 
      We are waiting for a padding cell from the client to come in, so that we
@@ -2224,8 +2612,14 @@ circpad_circ_responder_machine_init(void)
      before you send a padding response */
   circ_responder_machine->states[CIRCPAD_STATE_GAP].use_rtt_estimate = 1;
   circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_len = 6;
-  circ_responder_machine->states[CIRCPAD_STATE_GAP].start_usec = 5000;
-  circ_responder_machine->states[CIRCPAD_STATE_GAP].range_usec = 1000000;
+  /* Specify histogram bins */
+  circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[0]= 500;
+  circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[1]= 1000;
+  circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[2]= 2000;
+  circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[3]= 4000;
+  circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[4]= 8000;
+  circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_edges[5]= 16000;
+  /* Specify histogram tokens */
   circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[0] = 0;
   circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[1] = 1;
   circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[2] = 2;
@@ -2233,13 +2627,15 @@ circpad_circ_responder_machine_init(void)
   circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram[4] = 1;
   /* Total number of tokens */
   circ_responder_machine->states[CIRCPAD_STATE_GAP].histogram_total_tokens = 6;
+
   circ_responder_machine->states[CIRCPAD_STATE_GAP].token_removal =
       CIRCPAD_TOKEN_REMOVAL_CLOSEST_USEC;
 
   circ_responder_machine->machine_num = smartlist_len(relay_padding_machines);
-  smartlist_add(relay_padding_machines, circ_responder_machine);
+  circpad_register_padding_machine(circ_responder_machine,
+                                   relay_padding_machines);
 }
-#endif
+#endif /* defined(TOR_UNIT_TESTS) */
 
 /**
  * Initialize all of our padding machines.
@@ -2256,6 +2652,14 @@ circpad_machines_init(void)
   origin_padding_machines = smartlist_new();
   relay_padding_machines = smartlist_new();
 
+  /* Register machines for hiding client-side intro circuits */
+  circpad_machine_client_hide_intro_circuits(origin_padding_machines);
+  circpad_machine_relay_hide_intro_circuits(relay_padding_machines);
+
+  /* Register machines for hiding client-side rendezvous circuits */
+  circpad_machine_client_hide_rend_circuits(origin_padding_machines);
+  circpad_machine_relay_hide_rend_circuits(relay_padding_machines);
+
   // TODO: Parse machines from consensus and torrc
 #ifdef TOR_UNIT_TESTS
   circpad_circ_client_machine_init();
@@ -2292,8 +2696,9 @@ circpad_node_supports_padding(const node_t *node)
 {
   if (node->rs) {
     log_fn(LOG_INFO, LD_CIRC, "Checking padding: %s",
-           node->rs->pv.supports_padding ? "supported" : "unsupported");
-    return node->rs->pv.supports_padding;
+           node->rs->pv.supports_hs_setup_padding ?
+              "supported" : "unsupported");
+    return node->rs->pv.supports_hs_setup_padding;
   }
 
   log_fn(LOG_INFO, LD_CIRC, "Empty routerstatus in padding check");
@@ -2306,8 +2711,8 @@ circpad_node_supports_padding(const node_t *node)
  * Returns node_t from the consensus for that hop, if it is opened.
  * Otherwise returns NULL.
  */
-static const node_t *
-circuit_get_nth_node(origin_circuit_t *circ, int hop)
+MOCK_IMPL(STATIC const node_t *,
+circuit_get_nth_node,(origin_circuit_t *circ, int hop))
 {
   crypt_path_t *iter = circuit_get_cpath_hop(circ, hop);
 
@@ -2370,8 +2775,9 @@ circpad_negotiate_padding(origin_circuit_t *circ,
         &type)) < 0)
     return -1;
 
-  log_fn(LOG_INFO,LD_CIRC, "Negotiating padding on circuit %u",
-         circ->global_identifier);
+  log_fn(LOG_INFO,LD_CIRC,
+         "Negotiating padding on circuit %u (%d), command %d",
+         circ->global_identifier, TO_CIRCUIT(circ)->purpose, command);
 
   return circpad_send_command_to_hop(circ, target_hopnum,
                                      RELAY_COMMAND_PADDING_NEGOTIATE,
@@ -2434,7 +2840,8 @@ circpad_handle_padding_negotiate(circuit_t *circ, cell_t *cell)
 
   if (CIRCUIT_IS_ORIGIN(circ)) {
     log_fn(LOG_PROTOCOL_WARN, LD_CIRC,
-           "Padding negotiate cell unsupported at origin.");
+           "Padding negotiate cell unsupported at origin (circuit %u)",
+           TO_ORIGIN_CIRCUIT(circ)->global_identifier);
     return -1;
   }
 
@@ -2461,6 +2868,7 @@ circpad_handle_padding_negotiate(circuit_t *circ, cell_t *cell)
                             const circpad_machine_spec_t *, m) {
       if (m->machine_num == negotiate->machine_type) {
         circpad_setup_machine_on_circ(circ, m);
+        circpad_cell_event_nonpadding_received(circ);
         goto done;
       }
     } SMARTLIST_FOREACH_END(m);
@@ -2500,20 +2908,24 @@ circpad_handle_padding_negotiated(circuit_t *circ, cell_t *cell,
 
   /* Verify this came from the expected hop */
   if (!circpad_padding_is_from_expected_hop(circ, layer_hint)) {
-    log_fn(LOG_WARN, LD_CIRC,
-           "Padding negotiated cell from wrong hop!");
+    log_fn(LOG_PROTOCOL_WARN, LD_CIRC,
+           "Padding negotiated cell from wrong hop on circuit %u",
+             TO_ORIGIN_CIRCUIT(circ)->global_identifier);
     return -1;
   }
 
   if (circpad_negotiated_parse(&negotiated, cell->payload+RELAY_HEADER_SIZE,
                                CELL_PAYLOAD_SIZE-RELAY_HEADER_SIZE) < 0) {
     log_fn(LOG_PROTOCOL_WARN, LD_CIRC,
-          "Received malformed PADDING_NEGOTIATED cell; "
-          "dropping.");
+          "Received malformed PADDING_NEGOTIATED cell on circuit %u; "
+          "dropping.", TO_ORIGIN_CIRCUIT(circ)->global_identifier);
     return -1;
   }
 
   if (negotiated->command == CIRCPAD_COMMAND_STOP) {
+    log_info(LD_CIRC,
+             "Received STOP command on PADDING_NEGOTIATED for circuit %u",
+             TO_ORIGIN_CIRCUIT(circ)->global_identifier);
     /* There may not be a padding_info here if we shut down the
      * machine in circpad_shutdown_old_machines(). Or, if
      * circpad_add_matching_matchines() added a new machine,
@@ -2527,13 +2939,45 @@ circpad_handle_padding_negotiated(circuit_t *circ, cell_t *cell,
     free_circ_machineinfos_with_machine_num(circ, negotiated->machine_type);
     TO_ORIGIN_CIRCUIT(circ)->padding_negotiation_failed = 1;
     log_fn(LOG_PROTOCOL_WARN, LD_CIRC,
-           "Middle node did not accept our padding request.");
+           "Middle node did not accept our padding request on circuit %u (%d)",
+           TO_ORIGIN_CIRCUIT(circ)->global_identifier,
+           circ->purpose);
   }
 
   circpad_negotiated_free(negotiated);
   return 0;
 }
 
+/** Free memory allocated by this machine spec. */
+STATIC void
+machine_spec_free_(circpad_machine_spec_t *m)
+{
+  if (!m) return;
+
+  tor_free(m->states);
+  tor_free(m);
+}
+
+/** Free all memory allocated by the circuitpadding subsystem. */
+void
+circpad_free_all(void)
+{
+  if (origin_padding_machines) {
+    SMARTLIST_FOREACH_BEGIN(origin_padding_machines,
+                            circpad_machine_spec_t *, m) {
+      machine_spec_free(m);
+    } SMARTLIST_FOREACH_END(m);
+    smartlist_free(origin_padding_machines);
+  }
+  if (relay_padding_machines) {
+    SMARTLIST_FOREACH_BEGIN(relay_padding_machines,
+                            circpad_machine_spec_t *, m) {
+      machine_spec_free(m);
+    } SMARTLIST_FOREACH_END(m);
+    smartlist_free(relay_padding_machines);
+  }
+}
+
 /* Serialization */
 // TODO: Should we use keyword=value here? Are there helpers for that?
 #if 0
@@ -2586,4 +3030,4 @@ circpad_string_to_machine(const char *str)
   return NULL;
 }
 
-#endif
+#endif /* 0 */
diff --git a/src/core/or/circuitpadding.h b/src/core/or/circuitpadding.h
index 92fd4fc2d..3cf40e11d 100644
--- a/src/core/or/circuitpadding.h
+++ b/src/core/or/circuitpadding.h
@@ -10,7 +10,7 @@
 #ifndef TOR_CIRCUITPADDING_H
 #define TOR_CIRCUITPADDING_H
 
-#include "src/trunnel/circpad_negotiation.h"
+#include "trunnel/circpad_negotiation.h"
 #include "lib/evloop/timers.h"
 
 struct circuit_t;
@@ -73,6 +73,7 @@ typedef uint64_t circpad_time_t;
 
 /** The type for timer delays, in microseconds */
 typedef uint32_t circpad_delay_t;
+#define CIRCPAD_DELAY_UNITS_PER_SECOND  (1000*1000)
 
 /**
  * An infinite padding cell delay means don't schedule any padding --
@@ -86,9 +87,16 @@ typedef uint32_t circpad_delay_t;
 #define CIRCPAD_DELAY_INFINITE  (UINT32_MAX)
 
 /**
+ * This is the maximum delay that the circuit padding system can have, in
+ * seconds.
+ */
+#define CIRCPAD_DELAY_MAX_SECS   \
+    ((CIRCPAD_DELAY_INFINITE/CIRCPAD_DELAY_UNITS_PER_SECOND)+1)
+
+/**
  * Macro to clarify when we're checking the infinity bin.
  *
- * Works with either circpad_state_t or circpad_machine_state_t
+ * Works with either circpad_state_t or circpad_machine_runtime_t
  */
 #define CIRCPAD_INFINITY_BIN(mi)  ((mi)->histogram_len-1)
 
@@ -152,6 +160,17 @@ typedef struct circpad_machine_conditions_t {
   /** Only apply the machine *if* vanguards are enabled */
   unsigned requires_vanguards : 1;
 
+  /**
+   * This machine is ok to use if reduced padding is set in consensus
+   * or torrc. This machine will still be applied even if reduced padding
+   * is not set; this flag only acts to exclude machines that don't have
+   * it set when reduced padding is requested. Therefore, reduced padding
+   * machines should appear at the lowest priority in the padding machine
+   * lists (aka first in the list), so that non-reduced padding machines
+   * for the same purpose are given a chance to apply when reduced padding
+   * is not requested. */
+  unsigned reduced_padding_ok : 1;
+
   /** Only apply the machine *if* the circuit's state matches any of
    *  the bits set in this bitmask. */
   circpad_circuit_state_t state_mask;
@@ -198,14 +217,23 @@ typedef enum {
  * These can be used instead of histograms for the inter-packet
  * timing distribution, or to specify a distribution on the number
  * of cells that can be sent while in a specific state of the state
- * machine. */
+ * machine.
+ *
+ * Each distribution takes up to two parameters which are described below. */
 typedef enum {
+  /* No probability distribution is used */
   CIRCPAD_DIST_NONE = 0,
+  /* Uniform distribution: param1 is lower bound and param2 is upper bound */
   CIRCPAD_DIST_UNIFORM = 1,
+  /* Logistic distribution: param1 is Mu, param2 is sigma. */
   CIRCPAD_DIST_LOGISTIC = 2,
+  /* Log-logistic distribution: param1 is Alpha, param2 is 1.0/Beta */
   CIRCPAD_DIST_LOG_LOGISTIC = 3,
+  /* Geometric distribution: param1 is 'p' (success probability) */
   CIRCPAD_DIST_GEOMETRIC = 4,
+  /* Weibull distribution: param1 is k, param2 is Lambda */
   CIRCPAD_DIST_WEIBULL = 5,
+  /* Generalized Pareto distribution: param1 is sigma, param2 is xi */
   CIRCPAD_DIST_PARETO = 6
 } circpad_distribution_type_t;
 
@@ -228,19 +256,24 @@ typedef uint16_t circpad_statenum_t;
 #define  CIRCPAD_STATENUM_MAX   (UINT16_MAX)
 
 /** A histogram is used to sample padding delays given a machine state.  This
- *  constant defines the maximum histogram width (i.e. the max number of bins)
+ *  constant defines the maximum histogram width (i.e. the max number of bins).
  *
- *  Each histogram bin is twice as large as the previous. Two exceptions: The
- *  first bin has zero width (which means that minimum delay is applied to the
- *  next padding cell), and the last bin (infinity bin) has infinite width
- *  (which means that the next padding cell will be delayed infinitely). */
-#define CIRCPAD_MAX_HISTOGRAM_LEN (sizeof(circpad_delay_t)*8 + 1)
+ * The current limit is arbitrary and could be raised if there is a need,
+ * however too many bins will be hard to serialize in the future.
+ *
+ * Memory concerns are not so great here since the corresponding histogram and
+ * histogram_edges arrays are global and not per-circuit.
+ *
+ * If we ever upgrade this to a value that can't be represented by 8-bits we
+ * also need to upgrade circpad_hist_index_t.
+ */
+#define CIRCPAD_MAX_HISTOGRAM_LEN (100)
 
 /**
  * A state of a padding state machine. The information here are immutable and
  * represent the initial form of the state; it does not get updated as things
  * happen. The mutable information that gets updated in runtime are carried in
- * a circpad_machine_state_t.
+ * a circpad_machine_runtime_t.
  *
  * This struct describes the histograms and parameters of a single
  * state in the adaptive padding machine. Instances of this struct
@@ -248,38 +281,60 @@ typedef uint16_t circpad_statenum_t;
  * or the consensus.
  */
 typedef struct circpad_state_t {
-  /** If a histogram is used for this state, this specifies the number of bins
-   *  of this histogram. Histograms must have at least 2 bins.
+  /**
+   * If a histogram is used for this state, this specifies the number of bins
+   * of this histogram. Histograms must have at least 2 bins.
+   *
+   * In particular, the following histogram:
+   *
+   * Tokens
+   *         +
+   *      10 |    +----+
+   *       9 |    |    |           +---------+
+   *       8 |    |    |           |         |
+   *       7 |    |    |     +-----+         |
+   *       6 +----+ Bin+-----+     |         +---------------+
+   *       5 |    | #1 |     |     |         |               |
+   *         | Bin|    | Bin | Bin |  Bin #4 |    Bin #5     |
+   *         | #0 |    | #2  | #3  |         | (infinity bin)|
+   *         |    |    |     |     |         |               |
+   *         |    |    |     |     |         |               |
+   *       0 +----+----+-----+-----+---------+---------------+
+   *         0   100  200   350   500      1000              ∞  microseconds
    *
-   *  If a delay probability distribution is used for this state, this is set
-   *  to 0. */
+   * would be specified the following way:
+   *    histogram_len = 6;
+   *    histogram[] =        {   6,  10,   6,  7,    9,     6 }
+   *    histogram_edges[] =  { 0, 100, 200, 350, 500, 1000 }
+   *
+   * The final bin is called the "infinity bin" and if it's chosen we don't
+   * schedule any padding. The infinity bin is strange because its lower edge
+   * is the max value of possible non-infinite delay allowed by this histogram,
+   * and its upper edge is CIRCPAD_DELAY_INFINITE. You can tell if the infinity
+   * bin is chosen by inspecting its bin index or inspecting its upper edge.
+   *
+   * If a delay probability distribution is used for this state, this is set
+   * to 0. */
   circpad_hist_index_t histogram_len;
   /** The histogram itself: an array of uint16s of tokens, whose
-   *  widths are exponentially spaced, in microseconds */
+   *  widths are exponentially spaced, in microseconds.
+   *
+   *  This array must have histogram_len elements that are strictly
+   *  monotonically increasing. */
   circpad_hist_token_t histogram[CIRCPAD_MAX_HISTOGRAM_LEN];
+  /* The histogram bin edges in usec.
+   *
+   * Each element of this array specifies the left edge of the corresponding
+   * bin. The rightmost edge is always infinity and is not specified in this
+   * array.
+   *
+   * This array must have histogram_len elements. */
+  circpad_delay_t histogram_edges[CIRCPAD_MAX_HISTOGRAM_LEN+1];
   /** Total number of tokens in this histogram. This is a constant and is *not*
    *  decremented every time we spend a token. It's used for initializing and
    *  refilling the histogram. */
   uint32_t histogram_total_tokens;
 
-  /** Minimum padding delay of this state in microseconds.
-   *
-   *  If histograms are used, this is the left (and right) bound of the first
-   *  bin (since it has zero width).
-   *
-   *  If a delay probability distribution is used, this represents the minimum
-   *  delay we can sample from the distribution.
-   */
-  circpad_delay_t start_usec;
-
-  /** If histograms are used, this is the width of the whole histogram in
-   *  microseconds, and it's used to calculate individual bin width.
-   *
-   *  If a delay probability distribution is used, this is used as the max
-   *  delay we can sample from the distribution.
-   */
-  circpad_delay_t range_usec;
-
   /**
    * Represents a delay probability distribution (aka IAT distribution). It's a
    * parametrized way of encoding inter-packet delay information in
@@ -292,6 +347,16 @@ typedef struct circpad_state_t {
    * results of sampling from this distribution (range_sec is used as a max).
    */
   circpad_distribution_t iat_dist;
+  /*  If a delay probability distribution is used, this is used as the max
+   *  value we can sample from the distribution. However, RTT measurements and
+   *  dist_added_shift gets applied on top of this value to derive the final
+   *  padding delay. */
+  circpad_delay_t dist_max_sample_usec;
+  /*  If a delay probability distribution is used and this is set, we will add
+   *  this value on top of the value sampled from the IAT distribution to
+   *  derive the final padding delay (We also add the RTT measurement if it's
+   *  enabled.). */
+  circpad_delay_t dist_added_shift_usec;
 
   /**
    * The length dist is a parameterized way of encoding how long this
@@ -430,7 +495,7 @@ typedef struct circpad_state_t {
  *
  * XXX: Play with layout to minimize space on x64 Linux (most common relay).
  */
-typedef struct circpad_machine_state_t {
+typedef struct circpad_machine_runtime_t {
   /** The callback pointer for the padding callbacks.
    *
    *  These timers stick around the machineinfo until the machineinfo's circuit
@@ -468,6 +533,14 @@ typedef struct circpad_machine_state_t {
   uint16_t nonpadding_sent;
 
   /**
+   * Timestamp of the most recent cell event (sent, received, padding,
+   * non-padding), in seconds from approx_time().
+   *
+   * Used as an emergency break to stop holding padding circuits open.
+   */
+  time_t last_cell_time_sec;
+
+  /**
    * EWMA estimate of the RTT of the circuit from this hop
    * to the exit end, in microseconds. */
   circpad_delay_t rtt_estimate_usec;
@@ -514,7 +587,7 @@ typedef struct circpad_machine_state_t {
    * CIRCPAD_MAX_MACHINES define). */
   unsigned machine_index : 1;
 
-} circpad_machine_state_t;
+} circpad_machine_runtime_t;
 
 /** Helper macro to get an actual state machine from a machineinfo */
 #define CIRCPAD_GET_MACHINE(machineinfo) \
@@ -530,6 +603,9 @@ typedef uint8_t circpad_machine_num_t;
 
 /** Global state machine structure from the consensus */
 typedef struct circpad_machine_spec_t {
+  /* Just a user-friendly machine name for logs */
+  const char *name;
+
   /** Global machine number */
   circpad_machine_num_t machine_num;
 
@@ -548,6 +624,19 @@ typedef struct circpad_machine_spec_t {
    *  1-indexed (ie: hop #1 is guard, #2 middle, #3 exit). */
   unsigned target_hopnum : 3;
 
+  /** If this flag is enabled, don't close circuits that use this machine even
+   *  if another part of Tor wants to close this circuit.
+   *
+   *  If this flag is set, the circuitpadding subsystem will close circuits the
+   *  moment the machine transitions to the END state, and only if the circuit
+   *  has already been asked to be closed by another part of Tor.
+   *
+   *  Circuits that should have been closed but were kept open by a padding
+   *  machine are re-purposed to CIRCUIT_PURPOSE_C_CIRCUIT_PADDING, hence
+   *  machines should take that purpose into account if they are filtering
+   *  circuits by purpose. */
+  unsigned manage_circ_lifetime : 1;
+
   /** This machine only kills fascists if the following conditions are met. */
   circpad_machine_conditions_t conditions;
 
@@ -573,6 +662,8 @@ typedef struct circpad_machine_spec_t {
 
 void circpad_new_consensus_params(const networkstatus_t *ns);
 
+int circpad_marked_circuit_for_padding(circuit_t *circ, int reason);
+
 /**
  * The following are event call-in points that are of interest to
  * the state machines. They are called during cell processing. */
@@ -592,11 +683,11 @@ void circpad_cell_event_padding_received(struct circuit_t *on_circ);
 
 /** Internal events are events the machines send to themselves */
 circpad_decision_t
-circpad_internal_event_infinity(circpad_machine_state_t *mi);
+circpad_internal_event_infinity(circpad_machine_runtime_t *mi);
 circpad_decision_t
-circpad_internal_event_bins_empty(circpad_machine_state_t *);
+circpad_internal_event_bins_empty(circpad_machine_runtime_t *);
 circpad_decision_t circpad_internal_event_state_length_up(
-                                  circpad_machine_state_t *);
+                                  circpad_machine_runtime_t *);
 
 /** Machine creation events are events that cause us to set up or
  *  tear down padding state machines. */
@@ -610,6 +701,8 @@ circpad_machine_event_circ_has_no_relay_early(struct origin_circuit_t *circ);
 
 void circpad_machines_init(void);
 void circpad_machines_free(void);
+void circpad_register_padding_machine(circpad_machine_spec_t *machine,
+                                      smartlist_t *machine_list);
 
 void circpad_machine_states_init(circpad_machine_spec_t *machine,
                                  circpad_statenum_t num_states);
@@ -638,59 +731,78 @@ bool circpad_padding_negotiated(struct circuit_t *circ,
                            uint8_t command,
                            uint8_t response);
 
+circpad_purpose_mask_t circpad_circ_purpose_to_mask(uint8_t circ_purpose);
+
 MOCK_DECL(circpad_decision_t,
-circpad_machine_schedule_padding,(circpad_machine_state_t *));
+circpad_machine_schedule_padding,(circpad_machine_runtime_t *));
 
 MOCK_DECL(circpad_decision_t,
-circpad_machine_spec_transition, (circpad_machine_state_t *mi,
+circpad_machine_spec_transition, (circpad_machine_runtime_t *mi,
                              circpad_event_t event));
 
 circpad_decision_t circpad_send_padding_cell_for_callback(
-                                 circpad_machine_state_t *mi);
+                                 circpad_machine_runtime_t *mi);
+
+void circpad_free_all(void);
 
 #ifdef CIRCUITPADDING_PRIVATE
+STATIC void  machine_spec_free_(circpad_machine_spec_t *m);
+#define machine_spec_free(chan) \
+  FREE_AND_NULL(circpad_machine_spec_t,machine_spec_free_, (m))
+
 STATIC circpad_delay_t
-circpad_machine_sample_delay(circpad_machine_state_t *mi);
+circpad_machine_sample_delay(circpad_machine_runtime_t *mi);
 
 STATIC bool
-circpad_machine_reached_padding_limit(circpad_machine_state_t *mi);
-
-STATIC
-circpad_decision_t circpad_machine_remove_token(circpad_machine_state_t *mi);
+circpad_machine_reached_padding_limit(circpad_machine_runtime_t *mi);
 
 STATIC circpad_delay_t
-circpad_histogram_bin_to_usec(const circpad_machine_state_t *mi,
+circpad_histogram_bin_to_usec(const circpad_machine_runtime_t *mi,
                               circpad_hist_index_t bin);
 
 STATIC const circpad_state_t *
-circpad_machine_current_state(const circpad_machine_state_t *mi);
+circpad_machine_current_state(const circpad_machine_runtime_t *mi);
+
+STATIC void circpad_machine_remove_token(circpad_machine_runtime_t *mi);
 
 STATIC circpad_hist_index_t circpad_histogram_usec_to_bin(
-                                       const circpad_machine_state_t *mi,
+                                       const circpad_machine_runtime_t *mi,
                                        circpad_delay_t us);
 
-STATIC circpad_machine_state_t *circpad_circuit_machineinfo_new(
+STATIC circpad_machine_runtime_t *circpad_circuit_machineinfo_new(
                                                struct circuit_t *on_circ,
                                                int machine_index);
-STATIC void circpad_machine_remove_higher_token(circpad_machine_state_t *mi,
+STATIC void circpad_machine_remove_higher_token(circpad_machine_runtime_t *mi,
                                          circpad_delay_t target_bin_us);
-STATIC void circpad_machine_remove_lower_token(circpad_machine_state_t *mi,
+STATIC void circpad_machine_remove_lower_token(circpad_machine_runtime_t *mi,
                                          circpad_delay_t target_bin_us);
-STATIC void circpad_machine_remove_closest_token(circpad_machine_state_t *mi,
+STATIC void circpad_machine_remove_closest_token(circpad_machine_runtime_t *mi,
                                          circpad_delay_t target_bin_us,
                                          bool use_usec);
-STATIC void circpad_machine_setup_tokens(circpad_machine_state_t *mi);
+STATIC void circpad_machine_setup_tokens(circpad_machine_runtime_t *mi);
 
 MOCK_DECL(STATIC signed_error_t,
 circpad_send_command_to_hop,(struct origin_circuit_t *circ, uint8_t hopnum,
                              uint8_t relay_command, const uint8_t *payload,
                              ssize_t payload_len));
 
+MOCK_DECL(STATIC const node_t *,
+circuit_get_nth_node,(origin_circuit_t *circ, int hop));
+
+STATIC circpad_delay_t
+histogram_get_bin_upper_bound(const circpad_machine_runtime_t *mi,
+                              circpad_hist_index_t bin);
+
+STATIC void
+circpad_add_matching_machines(origin_circuit_t *on_circ,
+                              smartlist_t *machines_sl);
+
 #ifdef TOR_UNIT_TESTS
 extern smartlist_t *origin_padding_machines;
 extern smartlist_t *relay_padding_machines;
-#endif
 
 #endif
 
-#endif
+#endif /* defined(CIRCUITPADDING_PRIVATE) */
+
+#endif /* !defined(TOR_CIRCUITPADDING_H) */
diff --git a/src/core/or/circuitpadding_machines.c b/src/core/or/circuitpadding_machines.c
new file mode 100644
index 000000000..75d2614ac
--- /dev/null
+++ b/src/core/or/circuitpadding_machines.c
@@ -0,0 +1,458 @@
+/* Copyright (c) 2019 The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file circuitpadding_machines.c
+ * \brief Circuit padding state machines
+ *
+ * \detail
+ *
+ * Introduce circuit padding machines that will be used by Tor circuits, as
+ * specified by proposal 302 "Hiding onion service clients using padding".
+ *
+ * Right now this file introduces two machines that aim to hide the client-side
+ * of onion service circuits against naive classifiers like the ones from the
+ * "Circuit Fingerprinting Attacks: Passive Deanonymization of Tor Hidden
+ * Services" paper from USENIX. By naive classifiers we mean classifiers that
+ * use basic features like "circuit construction circuits" and "incoming and
+ * outgoing cell counts" and "duration of activity".
+ *
+ * In particular, these machines aim to be lightweight and protect against
+ * these basic classifiers. They don't aim to protect against more advanced
+ * attacks that use deep learning or even correlate various circuit
+ * construction events together. Machines that fool such advanced classifiers
+ * are also possible, but they can't be so lightweight and might require more
+ * WTF-PAD features. So for now we opt for the following two machines:
+ *
+ * Client-side introduction circuit hiding machine:
+ *
+ *    This machine hides client-side introduction circuits by making their
+ *    circuit consruction sequence look like normal general circuits that
+ *    download directory information. Furthermore, the circuits are kept open
+ *    until all the padding has been sent, since intro circuits are usually
+ *    very short lived and this act as a distinguisher. For more info see
+ *    circpad_machine_client_hide_intro_circuits() and the sec.
+ *
+ * Client-side rendezvous circuit hiding machine:
+ *
+ *    This machine hides client-side rendezvous circuits by making their
+ *    circuit construction sequence look like normal general circuits. For more
+ *    details see circpad_machine_client_hide_rend_circuits() and the spec.
+ *
+ * TODO: These are simple machines that carefully manipulate the cells of the
+ *   initial circuit setup procedure to make them look like general
+ *   circuits. In the future, more states can be baked into their state machine
+ *   to do more advanced obfuscation.
+ **/
+
+#define CIRCUITPADDING_MACHINES_PRIVATE
+
+#include "core/or/or.h"
+#include "feature/nodelist/networkstatus.h"
+
+#include "lib/crypt_ops/crypto_rand.h"
+
+#include "core/or/circuitlist.h"
+
+#include "core/or/circuitpadding_machines.h"
+#include "core/or/circuitpadding.h"
+
+/** Create a client-side padding machine that aims to hide IP circuits. In
+ *  particular, it keeps intro circuits alive until a bunch of fake traffic has
+ *  been pushed through.
+ */
+void
+circpad_machine_client_hide_intro_circuits(smartlist_t *machines_sl)
+{
+  circpad_machine_spec_t *client_machine
+      = tor_malloc_zero(sizeof(circpad_machine_spec_t));
+
+  client_machine->name = "client_ip_circ";
+
+  client_machine->conditions.state_mask = CIRCPAD_CIRC_OPENED;
+  client_machine->target_hopnum = 2;
+
+  /* This is a client machine */
+  client_machine->is_origin_side = 1;
+
+  /* We only want to pad introduction circuits, and we want to start padding
+   * only after the INTRODUCE1 cell has been sent, so set the purposes
+   * appropriately.
+   *
+   * In particular we want introduction circuits to blend as much as possible
+   * with general circuits. Most general circuits have the following initial
+   * relay cell sequence (outgoing cells marked in [brackets]):
+   *
+   * [EXTEND2] -> EXTENDED2 -> [EXTEND2] -> EXTENDED2 -> [BEGIN] -> CONNECTED
+   *   -> [DATA] -> [DATA] -> DATA -> DATA...(inbound data cells continue)
+   *
+   * Whereas normal introduction circuits usually look like:
+   *
+   * [EXTEND2] -> EXTENDED2 -> [EXTEND2] -> EXTENDED2 -> [EXTEND2] -> EXTENDED2
+   *   -> [INTRO1] -> INTRODUCE_ACK
+   *
+   * This means that up to the sixth cell (first line of each sequence above),
+   * both general and intro circuits have identical cell sequences. After that
+   * we want to mimic the second line sequence of
+   *   -> [DATA] -> [DATA] -> DATA -> DATA...(inbound data cells continue)
+   *
+   * We achieve this by starting padding INTRODUCE1 has been sent. With padding
+   * negotiation cells, in the common case of the second line looks like:
+   *   -> [INTRO1] -> [PADDING_NEGOTIATE] -> PADDING_NEGOTIATED -> INTRO_ACK
+   *
+   * Then, the middle node will send between INTRO_MACHINE_MINIMUM_PADDING and
+   * INTRO_MACHINE_MAXIMUM_PADDING cells, to match the "...(inbound data cells
+   * continue)" portion of the trace (aka the rest of an HTTPS response body).
+   */
+  client_machine->conditions.purpose_mask =
+    circpad_circ_purpose_to_mask(CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT)|
+    circpad_circ_purpose_to_mask(CIRCUIT_PURPOSE_C_INTRODUCE_ACKED)|
+    circpad_circ_purpose_to_mask(CIRCUIT_PURPOSE_C_CIRCUIT_PADDING);
+
+  /* Keep the circuit alive even after the introduction has been finished,
+   * otherwise the short-term lifetime of the circuit will blow our cover */
+  client_machine->manage_circ_lifetime = 1;
+
+  /* Set padding machine limits to help guard against excessive padding */
+  client_machine->allowed_padding_count = INTRO_MACHINE_MAXIMUM_PADDING;
+  client_machine->max_padding_percent = 1;
+
+  /* Two states: START, OBFUSCATE_CIRC_SETUP (and END) */
+  circpad_machine_states_init(client_machine, 2);
+
+  /* For the origin-side machine, we transition to OBFUSCATE_CIRC_SETUP after
+   * sending PADDING_NEGOTIATE, and we stay there (without sending any padding)
+   * until we receive a STOP from the other side. */
+  client_machine->states[CIRCPAD_STATE_START].
+    next_state[CIRCPAD_EVENT_NONPADDING_SENT] =
+    CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP;
+
+  /* origin-side machine has no event reactions while in
+   * CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP, so no more state transitions here. */
+
+  /* The client side should never send padding, so it does not need
+   * to specify token removal, or a histogram definition or state lengths.
+   * That is all controlled by the middle node. */
+
+  /* Register the machine */
+  client_machine->machine_num = smartlist_len(machines_sl);
+  circpad_register_padding_machine(client_machine, machines_sl);
+
+  log_info(LD_CIRC,
+           "Registered client intro point hiding padding machine (%u)",
+           client_machine->machine_num);
+}
+
+/** Create a relay-side padding machine that aims to hide IP circuits. See
+ *  comments on the function above for more details on the workings of the
+ *  machine. */
+void
+circpad_machine_relay_hide_intro_circuits(smartlist_t *machines_sl)
+{
+  circpad_machine_spec_t *relay_machine
+      = tor_malloc_zero(sizeof(circpad_machine_spec_t));
+
+  relay_machine->name = "relay_ip_circ";
+
+  relay_machine->conditions.state_mask = CIRCPAD_CIRC_OPENED;
+  relay_machine->target_hopnum = 2;
+
+  /* This is a relay-side machine */
+  relay_machine->is_origin_side = 0;
+
+  /* We want to negotiate END from this side after all our padding is done, so
+   * that the origin-side machine goes into END state, and eventually closes
+   * the circuit. */
+  relay_machine->should_negotiate_end = 1;
+
+  /* Set padding machine limits to help guard against excessive padding */
+  relay_machine->allowed_padding_count = INTRO_MACHINE_MAXIMUM_PADDING;
+  relay_machine->max_padding_percent = 1;
+
+  /* Two states: START, OBFUSCATE_CIRC_SETUP (and END) */
+  circpad_machine_states_init(relay_machine, 2);
+
+  /* For the relay-side machine, we want to transition
+   * START -> OBFUSCATE_CIRC_SETUP upon first non-padding
+   * cell sent (PADDING_NEGOTIATED in this case).  */
+  relay_machine->states[CIRCPAD_STATE_START].
+    next_state[CIRCPAD_EVENT_NONPADDING_SENT] =
+    CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP;
+
+  /* For the relay-side, we want to transition from OBFUSCATE_CIRC_SETUP to END
+   * state when the length finishes. */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+      next_state[CIRCPAD_EVENT_LENGTH_COUNT] = CIRCPAD_STATE_END;
+
+  /* Now let's define the OBF -> OBF transitions that maintain our padding
+   * flow:
+   *
+   * For the relay-side machine, we want to keep on sending padding bytes even
+   * when nothing else happens on this circuit. */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    next_state[CIRCPAD_EVENT_PADDING_SENT] =
+    CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP;
+  /* For the relay-side machine, we need this transition so that we re-enter
+     the state, after PADDING_NEGOTIATED is sent. Otherwise, the remove token
+     function will disable the timer, and nothing will restart it since there
+     is no other motion on an intro circuit. */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    next_state[CIRCPAD_EVENT_NONPADDING_SENT] =
+    CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP;
+
+  /* Token removal strategy for OBFUSCATE_CIRC_SETUP state: Don't
+   * remove any tokens.
+   *
+   * We rely on the state length sampling and not token removal, to avoid
+   * the mallocs required to copy the histograms for token removal,
+   * and to avoid monotime calls needed to determine histogram
+   * bins for token removal. */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    token_removal = CIRCPAD_TOKEN_REMOVAL_NONE;
+
+  /* Figure out the length of the OBFUSCATE_CIRC_SETUP state so that it's
+   * randomized. The relay side will send between INTRO_MACHINE_MINIMUM_PADDING
+   * and INTRO_MACHINE_MAXIMUM_PADDING padding cells towards the client. */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    length_dist.type = CIRCPAD_DIST_UNIFORM;
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    length_dist.param1 = INTRO_MACHINE_MINIMUM_PADDING;
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    length_dist.param2 = INTRO_MACHINE_MAXIMUM_PADDING;
+
+  /* Configure histogram */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+     histogram_len = 2;
+
+  /* For the relay-side machine we want to batch padding instantly to pretend
+   * its an incoming directory download. So set the histogram edges tight:
+   * (1, 10ms, infinity). */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_edges[0] = 1000;
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_edges[1] = 10000;
+
+  /* We put all our tokens in bin 0, which means we want 100% probability
+   * for choosing a inter-packet delay of between 1000 and 10000 microseconds
+   * (1 to 10ms). Since we only have 1 bin, it doesn't matter how many tokens
+   * there are, 1000 out of 1000 is 100% */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram[0] = 1000;
+
+  /* just one bin, so setup the total tokens */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_total_tokens =
+      relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].histogram[0];
+
+  /* Register the machine */
+  relay_machine->machine_num = smartlist_len(machines_sl);
+  circpad_register_padding_machine(relay_machine, machines_sl);
+
+  log_info(LD_CIRC,
+           "Registered relay intro circuit hiding padding machine (%u)",
+           relay_machine->machine_num);
+}
+
+/************************** Rendezvous-circuit machine ***********************/
+
+/** Create a client-side padding machine that aims to hide rendezvous
+ *  circuits.*/
+void
+circpad_machine_client_hide_rend_circuits(smartlist_t *machines_sl)
+{
+  circpad_machine_spec_t *client_machine
+      = tor_malloc_zero(sizeof(circpad_machine_spec_t));
+
+  client_machine->name = "client_rp_circ";
+
+  /* Only pad after the circuit has been built and pad to the middle */
+  client_machine->conditions.state_mask = CIRCPAD_CIRC_OPENED;
+  client_machine->target_hopnum = 2;
+
+  /* This is a client machine */
+  client_machine->is_origin_side = 1;
+
+  /* We only want to pad rendezvous circuits, and we want to start padding only
+   * after the rendezvous circuit has been established.
+   *
+   * Following a similar argument as for intro circuits, we are aiming for
+   * padded rendezvous circuits to blend in with the initial cell sequence of
+   * general circuits which usually look like this:
+   *
+   * [EXTEND2] -> EXTENDED2 -> [EXTEND2] -> EXTENDED2 -> [BEGIN] -> CONNECTED
+   *    -> [DATA] -> [DATA] -> DATA -> DATA...(incoming cells continue)
+   *
+   * Whereas normal rendezvous circuits usually look like:
+   *
+   * [EXTEND2] -> EXTENDED2 -> [EXTEND2] -> EXTENDED2 -> [EST_REND] -> REND_EST
+   *    -> REND2 -> [BEGIN]
+   *
+   * This means that up to the sixth cell (in the first line), both general and
+   * rend circuits have identical cell sequences.
+   *
+   * After that we want to mimic a [DATA] -> [DATA] -> DATA -> DATA sequence.
+   *
+   * With padding negotiation right after the REND_ESTABLISHED, the sequence
+   * becomes:
+   *
+   * [EXTEND2] -> EXTENDED2 -> [EXTEND2] -> EXTENDED2 -> [EST_REND] -> REND_EST
+   *    -> [PADDING_NEGOTIATE] -> [DROP] -> PADDING_NEGOTIATED -> DROP...
+   *
+   * After which normal application DATA cells continue on the circuit.
+   *
+   * Hence this way we make rendezvous circuits look like general circuits up
+   * till the end of the circuit setup. */
+  client_machine->conditions.purpose_mask =
+    circpad_circ_purpose_to_mask(CIRCUIT_PURPOSE_C_REND_JOINED)|
+    circpad_circ_purpose_to_mask(CIRCUIT_PURPOSE_C_REND_READY)|
+    circpad_circ_purpose_to_mask(CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED);
+
+  /* Set padding machine limits to help guard against excessive padding */
+  client_machine->allowed_padding_count = 1;
+  client_machine->max_padding_percent = 1;
+
+  /* Two states: START, OBFUSCATE_CIRC_SETUP (and END) */
+  circpad_machine_states_init(client_machine, 2);
+
+  /* START -> OBFUSCATE_CIRC_SETUP transition upon sending the first
+   * non-padding cell (which is PADDING_NEGOTIATE) */
+  client_machine->states[CIRCPAD_STATE_START].
+    next_state[CIRCPAD_EVENT_NONPADDING_SENT] =
+    CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP;
+
+  /* OBFUSCATE_CIRC_SETUP -> END transition when we send our first
+   * padding packet and/or hit the state length (the state length is 1). */
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+      next_state[CIRCPAD_EVENT_PADDING_RECV] = CIRCPAD_STATE_END;
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+      next_state[CIRCPAD_EVENT_LENGTH_COUNT] = CIRCPAD_STATE_END;
+
+  /* Don't use a token removal strategy since we don't want to use monotime
+   * functions and we want to avoid mallocing histogram copies. We want
+   * this machine to be light. */
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    token_removal = CIRCPAD_TOKEN_REMOVAL_NONE;
+
+  /* Instead, to control the volume of padding (we just want to send a single
+   * padding cell) we will use a static state length. We just want one token,
+   * since we want to make the following pattern:
+   * [PADDING_NEGOTIATE] -> [DROP] -> PADDING_NEGOTIATED -> DROP */
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    length_dist.type = CIRCPAD_DIST_UNIFORM;
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    length_dist.param1 = 1;
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    length_dist.param2 = 2; // rand(1,2) is always 1
+
+  /* Histogram is: (0 msecs, 1 msec, infinity). We want this to be fast so
+   * that we send our outgoing [DROP] before the PADDING_NEGOTIATED comes
+   * back from the relay side. */
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_len = 2;
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_edges[0] = 0;
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_edges[1] = 1000;
+
+  /* We want a 100% probability of choosing an inter-packet delay of
+   * between 0 and 1ms. Since we don't use token removal,
+   * the number of tokens does not matter. (And also, state_length
+   * governs how many packets we send). */
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram[0] = 1;
+  client_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_total_tokens = 1;
+
+  /* Register the machine */
+  client_machine->machine_num = smartlist_len(machines_sl);
+  circpad_register_padding_machine(client_machine, machines_sl);
+
+  log_info(LD_CIRC,
+           "Registered client rendezvous circuit hiding padding machine (%u)",
+           client_machine->machine_num);
+}
+
+/** Create a relay-side padding machine that aims to hide IP circuits.
+ *
+ *  This is meant to follow the client-side machine.
+ */
+void
+circpad_machine_relay_hide_rend_circuits(smartlist_t *machines_sl)
+{
+  circpad_machine_spec_t *relay_machine
+    = tor_malloc_zero(sizeof(circpad_machine_spec_t));
+
+  relay_machine->name = "relay_rp_circ";
+
+  /* Only pad after the circuit has been built and pad to the middle */
+  relay_machine->conditions.min_hops = 2;
+  relay_machine->conditions.state_mask = CIRCPAD_CIRC_OPENED;
+  relay_machine->target_hopnum = 2;
+
+  /* This is a relay-side machine */
+  relay_machine->is_origin_side = 0;
+
+  /* Set padding machine limits to help guard against excessive padding */
+  relay_machine->allowed_padding_count = 1;
+  relay_machine->max_padding_percent = 1;
+
+  /* Two states: START, OBFUSCATE_CIRC_SETUP (and END) */
+  circpad_machine_states_init(relay_machine, 2);
+
+  /* START -> OBFUSCATE_CIRC_SETUP transition upon sending the first
+   * non-padding cell (which is PADDING_NEGOTIATED) */
+  relay_machine->states[CIRCPAD_STATE_START].
+    next_state[CIRCPAD_EVENT_NONPADDING_SENT] =
+    CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP;
+
+  /* OBFUSCATE_CIRC_SETUP -> END transition when we send our first
+   * padding packet and/or hit the state length (the state length is 1). */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+      next_state[CIRCPAD_EVENT_PADDING_RECV] = CIRCPAD_STATE_END;
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+      next_state[CIRCPAD_EVENT_LENGTH_COUNT] = CIRCPAD_STATE_END;
+
+  /* Don't use a token removal strategy since we don't want to use monotime
+   * functions and we want to avoid mallocing histogram copies. We want
+   * this machine to be light. */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    token_removal = CIRCPAD_TOKEN_REMOVAL_NONE;
+
+  /* Instead, to control the volume of padding (we just want to send a single
+   * padding cell) we will use a static state length. We just want one token,
+   * since we want to make the following pattern:
+   * [PADDING_NEGOTIATE] -> [DROP] -> PADDING_NEGOTIATED -> DROP */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    length_dist.type = CIRCPAD_DIST_UNIFORM;
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    length_dist.param1 = 1;
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    length_dist.param2 = 2; // rand(1,2) is always 1
+
+  /* Histogram is: (0 msecs, 1 msec, infinity). We want this to be fast so
+   * that the outgoing DROP cell is sent immediately after the
+   * PADDING_NEGOTIATED. */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_len = 2;
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_edges[0] = 0;
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_edges[1] = 1000;
+
+  /* We want a 100% probability of choosing an inter-packet delay of
+   * between 0 and 1ms. Since we don't use token removal,
+   * the number of tokens does not matter. (And also, state_length
+   * governs how many packets we send). */
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram[0] = 1;
+  relay_machine->states[CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP].
+    histogram_total_tokens = 1;
+
+  /* Register the machine */
+  relay_machine->machine_num = smartlist_len(machines_sl);
+  circpad_register_padding_machine(relay_machine, machines_sl);
+
+  log_info(LD_CIRC,
+           "Registered relay rendezvous circuit hiding padding machine (%u)",
+           relay_machine->machine_num);
+}
diff --git a/src/core/or/circuitpadding_machines.h b/src/core/or/circuitpadding_machines.h
new file mode 100644
index 000000000..3c9798d42
--- /dev/null
+++ b/src/core/or/circuitpadding_machines.h
@@ -0,0 +1,35 @@
+/* Copyright (c) 2018 The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file circuitpadding_machines.h
+ * \brief Header file for circuitpadding_machines.c.
+ **/
+
+#ifndef TOR_CIRCUITPADDING_MACHINES_H
+#define TOR_CIRCUITPADDING_MACHINES_H
+
+void circpad_machine_relay_hide_intro_circuits(smartlist_t *machines_sl);
+void circpad_machine_client_hide_intro_circuits(smartlist_t *machines_sl);
+void circpad_machine_relay_hide_rend_circuits(smartlist_t *machines_sl);
+void circpad_machine_client_hide_rend_circuits(smartlist_t *machines_sl);
+
+#ifdef CIRCUITPADDING_MACHINES_PRIVATE
+
+/** State of the padding machines that actually sends padding */
+#define CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP CIRCPAD_STATE_BURST
+
+/** Constants defining the amount of padding that a machine will send to hide
+ *  HS circuits. The actual value is sampled uniformly random between the
+ *  min/max values.
+ */
+
+/** Minimum number of relay-side padding cells to be sent by this machine */
+#define INTRO_MACHINE_MINIMUM_PADDING 7
+/** Maximum number of relay-side padding cells to be sent by this machine.
+ *  The actual value will be sampled between the min and max.*/
+#define INTRO_MACHINE_MAXIMUM_PADDING 10
+
+#endif /* defined(CIRCUITPADDING_MACHINES_PRIVATE) */
+
+#endif /* !defined(TOR_CIRCUITPADDING_MACHINES_H) */
diff --git a/src/core/or/circuitstats.c b/src/core/or/circuitstats.c
index c6ea2fff9..03eea1d77 100644
--- a/src/core/or/circuitstats.c
+++ b/src/core/or/circuitstats.c
@@ -30,7 +30,7 @@
 #include "core/or/circuitstats.h"
 #include "app/config/config.h"
 #include "app/config/confparse.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "core/mainloop/mainloop.h"
 #include "feature/nodelist/networkstatus.h"
@@ -44,6 +44,7 @@
 #include "lib/time/tvdiff.h"
 #include "lib/encoding/confline.h"
 #include "feature/dirauth/authmode.h"
+#include "feature/relay/relay_periodic.h"
 
 #include "core/or/crypt_path_st.h"
 #include "core/or/origin_circuit_st.h"
@@ -1420,6 +1421,7 @@ void
 circuit_build_times_network_is_live(circuit_build_times_t *cbt)
 {
   time_t now = approx_time();
+  // XXXX this should use pubsub
   if (cbt->liveness.nonlive_timeouts > 0) {
     time_t time_since_live = now - cbt->liveness.network_last_live;
     log_notice(LD_CIRC,
diff --git a/src/core/or/circuituse.c b/src/core/or/circuituse.c
index fd782c0cd..18b419e99 100644
--- a/src/core/or/circuituse.c
+++ b/src/core/or/circuituse.c
@@ -42,7 +42,7 @@
 #include "feature/client/bridges.h"
 #include "feature/client/circpathbias.h"
 #include "feature/client/entrynodes.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dircommon/directory.h"
 #include "feature/hs/hs_circuit.h"
 #include "feature/hs/hs_client.h"
@@ -70,7 +70,7 @@
 #include "core/or/origin_circuit_st.h"
 #include "core/or/socks_request_st.h"
 
-static void circuit_expire_old_circuits_clientside(void);
+STATIC void circuit_expire_old_circuits_clientside(void);
 static void circuit_increment_failure_count(void);
 
 /** Check whether the hidden service destination of the stream at
@@ -178,7 +178,6 @@ circuit_is_acceptable(const origin_circuit_t *origin_circ,
       purpose == CIRCUIT_PURPOSE_S_HSDIR_POST ||
       purpose == CIRCUIT_PURPOSE_C_HSDIR_GET) {
     tor_addr_t addr;
-    const int family = tor_addr_parse(&addr, conn->socks_request->address);
     if (!exitnode && !build_state->onehop_tunnel) {
       log_debug(LD_CIRC,"Not considering circuit with unknown router.");
       return 0; /* this circuit is screwed and doesn't know it yet,
@@ -199,6 +198,8 @@ circuit_is_acceptable(const origin_circuit_t *origin_circ,
           return 0; /* this is a circuit to somewhere else */
         if (tor_digest_is_zero(digest)) {
           /* we don't know the digest; have to compare addr:port */
+          const int family = tor_addr_parse(&addr,
+                                            conn->socks_request->address);
           if (family < 0 ||
               !tor_addr_eq(&build_state->chosen_exit->addr, &addr) ||
               build_state->chosen_exit->port != conn->socks_request->port)
@@ -211,12 +212,14 @@ circuit_is_acceptable(const origin_circuit_t *origin_circ,
         return 0;
       }
     }
-    if (origin_circ->prepend_policy && family != -1) {
-      int r = compare_tor_addr_to_addr_policy(&addr,
-                                              conn->socks_request->port,
-                                              origin_circ->prepend_policy);
-      if (r == ADDR_POLICY_REJECTED)
-        return 0;
+    if (origin_circ->prepend_policy) {
+      if (tor_addr_parse(&addr, conn->socks_request->address) != -1) {
+        int r = compare_tor_addr_to_addr_policy(&addr,
+                                                conn->socks_request->port,
+                                                origin_circ->prepend_policy);
+        if (r == ADDR_POLICY_REJECTED)
+          return 0;
+      }
     }
     if (exitnode && !connection_ap_can_use_exit(conn, exitnode)) {
       /* can't exit from this router */
@@ -1471,7 +1474,7 @@ circuit_detach_stream(circuit_t *circ, edge_connection_t *conn)
 /** Find each circuit that has been unused for too long, or dirty
  * for too long and has no streams on it: mark it for close.
  */
-static void
+STATIC void
 circuit_expire_old_circuits_clientside(void)
 {
   struct timeval cutoff, now;
@@ -1511,6 +1514,7 @@ circuit_expire_old_circuits_clientside(void)
                 circ->purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT ||
                 circ->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO ||
                 circ->purpose == CIRCUIT_PURPOSE_TESTING ||
+                circ->purpose == CIRCUIT_PURPOSE_C_CIRCUIT_PADDING ||
                 (circ->purpose >= CIRCUIT_PURPOSE_C_INTRODUCING &&
                 circ->purpose <= CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) ||
                 circ->purpose == CIRCUIT_PURPOSE_S_CONNECT_REND) {
@@ -3078,6 +3082,12 @@ circuit_change_purpose(circuit_t *circ, uint8_t new_purpose)
               circ->purpose,
               circuit_purpose_to_string(new_purpose),
               new_purpose);
+
+    /* Take specific actions if we are repurposing a hidden service circuit. */
+    if (circuit_purpose_is_hidden_service(circ->purpose) &&
+        !circuit_purpose_is_hidden_service(new_purpose)) {
+      hs_circ_cleanup(circ);
+    }
   }
 
   old_purpose = circ->purpose;
@@ -3121,7 +3131,9 @@ circuit_sent_valid_data(origin_circuit_t *circ, uint16_t relay_body_len)
 {
   if (!circ) return;
 
-  tor_assert_nonfatal(relay_body_len <= RELAY_PAYLOAD_SIZE);
+  tor_assertf_nonfatal(relay_body_len <= RELAY_PAYLOAD_SIZE,
+                       "Wrong relay_body_len: %d (should be at most %d)",
+                       relay_body_len, RELAY_PAYLOAD_SIZE);
 
   circ->n_delivered_written_circ_bw =
       tor_add_u32_nowrap(circ->n_delivered_written_circ_bw, relay_body_len);
diff --git a/src/core/or/command.c b/src/core/or/command.c
index 5fb6640c2..77e5447ce 100644
--- a/src/core/or/command.c
+++ b/src/core/or/command.c
@@ -49,7 +49,7 @@
 #include "core/or/dos.h"
 #include "core/or/onion.h"
 #include "core/or/relay.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/hibernate/hibernate.h"
 #include "feature/nodelist/describe.h"
 #include "feature/nodelist/nodelist.h"
diff --git a/src/core/or/connection_edge.c b/src/core/or/connection_edge.c
index cc240bdc9..c08d2a9ff 100644
--- a/src/core/or/connection_edge.c
+++ b/src/core/or/connection_edge.c
@@ -73,12 +73,13 @@
 #include "core/or/policies.h"
 #include "core/or/reasons.h"
 #include "core/or/relay.h"
+#include "core/or/sendme.h"
 #include "core/proto/proto_http.h"
 #include "core/proto/proto_socks.h"
 #include "feature/client/addressmap.h"
 #include "feature/client/circpathbias.h"
 #include "feature/client/dnsserv.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dircache/dirserv.h"
 #include "feature/dircommon/directory.h"
 #include "feature/hibernate/hibernate.h"
@@ -767,7 +768,7 @@ connection_edge_flushed_some(edge_connection_t *conn)
 
       /* falls through. */
     case EXIT_CONN_STATE_OPEN:
-      connection_edge_consider_sending_sendme(conn);
+      sendme_connection_edge_consider_sending(conn);
       break;
   }
   return 0;
@@ -791,7 +792,7 @@ connection_edge_finished_flushing(edge_connection_t *conn)
   switch (conn->base_.state) {
     case AP_CONN_STATE_OPEN:
     case EXIT_CONN_STATE_OPEN:
-      connection_edge_consider_sending_sendme(conn);
+      sendme_connection_edge_consider_sending(conn);
       return 0;
     case AP_CONN_STATE_SOCKS_WAIT:
     case AP_CONN_STATE_NATD_WAIT:
@@ -2810,6 +2811,31 @@ connection_ap_process_natd(entry_connection_t *conn)
   return connection_ap_rewrite_and_attach_if_allowed(conn, NULL, NULL);
 }
 
+static const char HTTP_CONNECT_IS_NOT_AN_HTTP_PROXY_MSG[] =
+  "HTTP/1.0 405 Method Not Allowed\r\n"
+  "Content-Type: text/html; charset=iso-8859-1\r\n\r\n"
+  "<html>\n"
+  "<head>\n"
+  "<title>This is an HTTP CONNECT tunnel, not a full HTTP Proxy</title>\n"
+  "</head>\n"
+  "<body>\n"
+  "<h1>This is an HTTP CONNECT tunnel, not an HTTP proxy.</h1>\n"
+  "<p>\n"
+  "It appears you have configured your web browser to use this Tor port as\n"
+  "an HTTP proxy.\n"
+  "</p><p>\n"
+  "This is not correct: This port is configured as a CONNECT tunnel, not\n"
+  "an HTTP proxy. Please configure your client accordingly.  You can also\n"
+  "use HTTPS; then the client should automatically use HTTP CONNECT."
+  "</p>\n"
+  "<p>\n"
+  "See <a href=\"https://www.torproject.org/documentation.html\">"
+  "https://www.torproject.org/documentation.html</a> for more "
+  "information.\n"
+  "</p>\n"
+  "</body>\n"
+  "</html>\n";
+
 /** Called on an HTTP CONNECT entry connection when some bytes have arrived,
  * but we have not yet received a full HTTP CONNECT request.  Try to parse an
  * HTTP CONNECT request from the connection's inbuf.  On success, set up the
@@ -2850,7 +2876,7 @@ connection_ap_process_http_connect(entry_connection_t *conn)
   tor_assert(command);
   tor_assert(addrport);
   if (strcasecmp(command, "connect")) {
-    errmsg = "HTTP/1.0 405 Method Not Allowed\r\n\r\n";
+    errmsg = HTTP_CONNECT_IS_NOT_AN_HTTP_PROXY_MSG;
     goto err;
   }
 
@@ -4539,6 +4565,25 @@ circuit_clear_isolation(origin_circuit_t *circ)
   circ->socks_username_len = circ->socks_password_len = 0;
 }
 
+/** Send an END and mark for close the given edge connection conn using the
+ * given reason that has to be a stream reason.
+ *
+ * Note: We don't unattached the AP connection (if applicable) because we
+ * don't want to flush the remaining data. This function aims at ending
+ * everything quickly regardless of the connection state.
+ *
+ * This function can't fail and does nothing if conn is NULL. */
+void
+connection_edge_end_close(edge_connection_t *conn, uint8_t reason)
+{
+  if (!conn) {
+    return;
+  }
+
+  connection_edge_end(conn, reason);
+  connection_mark_for_close(TO_CONN(conn));
+}
+
 /** Free all storage held in module-scoped variables for connection_edge.c */
 void
 connection_edge_free_all(void)
diff --git a/src/core/or/connection_edge.h b/src/core/or/connection_edge.h
index 68d8b19a1..e82b6bd76 100644
--- a/src/core/or/connection_edge.h
+++ b/src/core/or/connection_edge.h
@@ -80,6 +80,7 @@ int connection_edge_process_inbuf(edge_connection_t *conn,
 int connection_edge_destroy(circid_t circ_id, edge_connection_t *conn);
 int connection_edge_end(edge_connection_t *conn, uint8_t reason);
 int connection_edge_end_errno(edge_connection_t *conn);
+void connection_edge_end_close(edge_connection_t *conn, uint8_t reason);
 int connection_edge_flushed_some(edge_connection_t *conn);
 int connection_edge_finished_flushing(edge_connection_t *conn);
 int connection_edge_finished_connecting(edge_connection_t *conn);
diff --git a/src/core/or/connection_or.c b/src/core/or/connection_or.c
index debf482cb..830e09fd5 100644
--- a/src/core/or/connection_or.c
+++ b/src/core/or/connection_or.c
@@ -39,7 +39,7 @@
 #include "app/config/config.h"
 #include "core/mainloop/connection.h"
 #include "core/or/connection_or.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/crypt_ops/crypto_util.h"
 #include "feature/dirauth/reachability.h"
@@ -2308,6 +2308,8 @@ connection_or_write_cell_to_buf(const cell_t *cell, or_connection_t *conn)
 
   cell_pack(&networkcell, cell, conn->wide_circ_ids);
 
+  /* We need to count padding cells from this non-packed code path
+   * since they are sent via chan->write_cell() (which is not packed) */
   rep_hist_padding_count_write(PADDING_TYPE_TOTAL);
   if (cell->command == CELL_PADDING)
     rep_hist_padding_count_write(PADDING_TYPE_CELL);
@@ -2318,7 +2320,7 @@ connection_or_write_cell_to_buf(const cell_t *cell, or_connection_t *conn)
   if (conn->chan) {
     channel_timestamp_active(TLS_CHAN_TO_BASE(conn->chan));
 
-    if (TLS_CHAN_TO_BASE(conn->chan)->currently_padding) {
+    if (TLS_CHAN_TO_BASE(conn->chan)->padding_enabled) {
       rep_hist_padding_count_write(PADDING_TYPE_ENABLED_TOTAL);
       if (cell->command == CELL_PADDING)
         rep_hist_padding_count_write(PADDING_TYPE_ENABLED_CELL);
@@ -2348,6 +2350,7 @@ connection_or_write_var_cell_to_buf,(const var_cell_t *cell,
   if (conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3)
     or_handshake_state_record_var_cell(conn, conn->handshake_state, cell, 0);
 
+  rep_hist_padding_count_write(PADDING_TYPE_TOTAL);
   /* Touch the channel's active timestamp if there is one */
   if (conn->chan)
     channel_timestamp_active(TLS_CHAN_TO_BASE(conn->chan));
diff --git a/src/core/or/connection_st.h b/src/core/or/connection_st.h
index d1430eda1..1c42a56d6 100644
--- a/src/core/or/connection_st.h
+++ b/src/core/or/connection_st.h
@@ -146,4 +146,4 @@ struct connection_t {
  * directory connection. */
 #define DIR_CONN_IS_SERVER(conn) ((conn)->purpose == DIR_PURPOSE_SERVER)
 
-#endif
+#endif /* !defined(CONNECTION_ST_H) */
diff --git a/src/core/or/cpath_build_state_st.h b/src/core/or/cpath_build_state_st.h
index dbe596d85..4572a1043 100644
--- a/src/core/or/cpath_build_state_st.h
+++ b/src/core/or/cpath_build_state_st.h
@@ -34,5 +34,5 @@ struct cpath_build_state_t {
   time_t expiry_time;
 };
 
-#endif
+#endif /* !defined(CIRCUIT_BUILD_STATE_ST_ST_H) */
 
diff --git a/src/core/or/crypt_path.c b/src/core/or/crypt_path.c
new file mode 100644
index 000000000..6d5245510
--- /dev/null
+++ b/src/core/or/crypt_path.c
@@ -0,0 +1,262 @@
+/*
+ * Copyright (c) 2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file crypt_path.c
+ *
+ * \brief Functions dealing with layered circuit encryption. This file aims to
+ *   provide an API around the crypt_path_t structure which holds crypto
+ *   information about a specific hop of a circuit.
+ *
+ * TODO: We should eventually move all functions dealing and manipulating
+ *   crypt_path_t to this file, so that eventually we encapsulate more and more
+ *   of crypt_path_t. Here are some more functions that can be moved here with
+ *   some more effort:
+ *
+ *   - circuit_list_path_impl()
+ *   - Functions dealing with cpaths in HSv2 create_rend_cpath() and
+ *     create_rend_cpath_legacy()
+ *   - The cpath related parts of rend_service_receive_introduction() and
+ *     rend_client_send_introduction().
+ **/
+
+#define CRYPT_PATH_PRIVATE
+
+#include "core/or/or.h"
+#include "core/or/crypt_path.h"
+
+#include "core/crypto/relay_crypto.h"
+#include "core/crypto/onion_crypto.h"
+#include "core/or/circuitbuild.h"
+#include "core/or/circuitlist.h"
+
+#include "lib/crypt_ops/crypto_dh.h"
+#include "lib/crypt_ops/crypto_util.h"
+
+#include "core/or/crypt_path_st.h"
+#include "core/or/cell_st.h"
+
+/** Add <b>new_hop</b> to the end of the doubly-linked-list <b>head_ptr</b>.
+ * This function is used to extend cpath by another hop.
+ */
+void
+cpath_extend_linked_list(crypt_path_t **head_ptr, crypt_path_t *new_hop)
+{
+  if (*head_ptr) {
+    new_hop->next = (*head_ptr);
+    new_hop->prev = (*head_ptr)->prev;
+    (*head_ptr)->prev->next = new_hop;
+    (*head_ptr)->prev = new_hop;
+  } else {
+    *head_ptr = new_hop;
+    new_hop->prev = new_hop->next = new_hop;
+  }
+}
+
+/** Create a new hop, annotate it with information about its
+ * corresponding router <b>choice</b>, and append it to the
+ * end of the cpath <b>head_ptr</b>. */
+int
+cpath_append_hop(crypt_path_t **head_ptr, extend_info_t *choice)
+{
+  crypt_path_t *hop = tor_malloc_zero(sizeof(crypt_path_t));
+
+  /* link hop into the cpath, at the end. */
+  cpath_extend_linked_list(head_ptr, hop);
+
+  hop->magic = CRYPT_PATH_MAGIC;
+  hop->state = CPATH_STATE_CLOSED;
+
+  hop->extend_info = extend_info_dup(choice);
+
+  hop->package_window = circuit_initial_package_window();
+  hop->deliver_window = CIRCWINDOW_START;
+
+  return 0;
+}
+
+/** Verify that cpath <b>cp</b> has all of its invariants
+ * correct. Trigger an assert if anything is invalid.
+ */
+void
+cpath_assert_ok(const crypt_path_t *cp)
+{
+  const crypt_path_t *start = cp;
+
+  do {
+    cpath_assert_layer_ok(cp);
+    /* layers must be in sequence of: "open* awaiting? closed*" */
+    if (cp != start) {
+      if (cp->state == CPATH_STATE_AWAITING_KEYS) {
+        tor_assert(cp->prev->state == CPATH_STATE_OPEN);
+      } else if (cp->state == CPATH_STATE_OPEN) {
+        tor_assert(cp->prev->state == CPATH_STATE_OPEN);
+      }
+    }
+    cp = cp->next;
+    tor_assert(cp);
+  } while (cp != start);
+}
+
+/** Verify that cpath layer <b>cp</b> has all of its invariants
+ * correct. Trigger an assert if anything is invalid.
+ */
+void
+cpath_assert_layer_ok(const crypt_path_t *cp)
+{
+//  tor_assert(cp->addr); /* these are zero for rendezvous extra-hops */
+//  tor_assert(cp->port);
+  tor_assert(cp);
+  tor_assert(cp->magic == CRYPT_PATH_MAGIC);
+  switch (cp->state)
+    {
+    case CPATH_STATE_OPEN:
+      relay_crypto_assert_ok(&cp->pvt_crypto);
+      /* fall through */
+    case CPATH_STATE_CLOSED:
+      /*XXXX Assert that there's no handshake_state either. */
+      tor_assert(!cp->rend_dh_handshake_state);
+      break;
+    case CPATH_STATE_AWAITING_KEYS:
+      /* tor_assert(cp->dh_handshake_state); */
+      break;
+    default:
+      log_fn(LOG_ERR, LD_BUG, "Unexpected state %d", cp->state);
+      tor_assert(0);
+    }
+  tor_assert(cp->package_window >= 0);
+  tor_assert(cp->deliver_window >= 0);
+}
+
+/** Initialize cpath-\>{f|b}_{crypto|digest} from the key material in key_data.
+ *
+ * If <b>is_hs_v3</b> is set, this cpath will be used for next gen hidden
+ * service circuits and <b>key_data</b> must be at least
+ * HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN bytes in length.
+ *
+ * If <b>is_hs_v3</b> is not set, key_data must contain CPATH_KEY_MATERIAL_LEN
+ * bytes, which are used as follows:
+ *   - 20 to initialize f_digest
+ *   - 20 to initialize b_digest
+ *   - 16 to key f_crypto
+ *   - 16 to key b_crypto
+ *
+ * (If 'reverse' is true, then f_XX and b_XX are swapped.)
+ *
+ * Return 0 if init was successful, else -1 if it failed.
+ */
+int
+cpath_init_circuit_crypto(crypt_path_t *cpath,
+                          const char *key_data, size_t key_data_len,
+                          int reverse, int is_hs_v3)
+{
+
+  tor_assert(cpath);
+  return relay_crypto_init(&cpath->pvt_crypto, key_data, key_data_len,
+                           reverse, is_hs_v3);
+}
+
+/** Deallocate space associated with the cpath node <b>victim</b>. */
+void
+cpath_free(crypt_path_t *victim)
+{
+  if (!victim)
+    return;
+
+  relay_crypto_clear(&victim->pvt_crypto);
+  onion_handshake_state_release(&victim->handshake_state);
+  crypto_dh_free(victim->rend_dh_handshake_state);
+  extend_info_free(victim->extend_info);
+
+  memwipe(victim, 0xBB, sizeof(crypt_path_t)); /* poison memory */
+  tor_free(victim);
+}
+
+/********************** cpath crypto API *******************************/
+
+/** Encrypt or decrypt <b>payload</b> using the crypto of <b>cpath</b>. Actual
+ *  operation decided by <b>is_decrypt</b>.  */
+void
+cpath_crypt_cell(const crypt_path_t *cpath, uint8_t *payload, bool is_decrypt)
+{
+  if (is_decrypt) {
+    relay_crypt_one_payload(cpath->pvt_crypto.b_crypto, payload);
+  } else {
+    relay_crypt_one_payload(cpath->pvt_crypto.f_crypto, payload);
+  }
+}
+
+/** Getter for the incoming digest of <b>cpath</b>. */
+struct crypto_digest_t *
+cpath_get_incoming_digest(const crypt_path_t *cpath)
+{
+  return cpath->pvt_crypto.b_digest;
+}
+
+/** Set the right integrity digest on the outgoing <b>cell</b> based on the
+ *  cell payload and update the forward digest of <b>cpath</b>. */
+void
+cpath_set_cell_forward_digest(crypt_path_t *cpath, cell_t *cell)
+{
+  relay_set_digest(cpath->pvt_crypto.f_digest, cell);
+}
+
+/************ cpath sendme API ***************************/
+
+/** Return the sendme_digest of this <b>cpath</b>. */
+uint8_t *
+cpath_get_sendme_digest(crypt_path_t *cpath)
+{
+  return relay_crypto_get_sendme_digest(&cpath->pvt_crypto);
+}
+
+/** Record the cell digest, indicated by is_foward_digest or not, as the
+ * SENDME cell digest. */
+void
+cpath_sendme_record_cell_digest(crypt_path_t *cpath, bool is_foward_digest)
+{
+  tor_assert(cpath);
+  relay_crypto_record_sendme_digest(&cpath->pvt_crypto, is_foward_digest);
+}
+
+/************ other cpath functions ***************************/
+
+/** Return the first non-open hop in cpath, or return NULL if all
+ * hops are open. */
+crypt_path_t *
+cpath_get_next_non_open_hop(crypt_path_t *cpath)
+{
+  crypt_path_t *hop = cpath;
+  do {
+    if (hop->state != CPATH_STATE_OPEN)
+      return hop;
+    hop = hop->next;
+  } while (hop != cpath);
+  return NULL;
+}
+
+#ifdef TOR_UNIT_TESTS
+
+/** Unittest helper function: Count number of hops in cpath linked list. */
+unsigned int
+cpath_get_n_hops(crypt_path_t **head_ptr)
+{
+  unsigned int n_hops = 0;
+  crypt_path_t *tmp;
+
+  if (!*head_ptr) {
+    return 0;
+  }
+
+  tmp = *head_ptr;
+  do {
+    n_hops++;
+    tmp = tmp->next;
+  } while (tmp != *head_ptr);
+
+  return n_hops;
+}
+
+#endif /* defined(TOR_UNIT_TESTS) */
+
diff --git a/src/core/or/crypt_path.h b/src/core/or/crypt_path.h
new file mode 100644
index 000000000..7a95fec2b
--- /dev/null
+++ b/src/core/or/crypt_path.h
@@ -0,0 +1,46 @@
+/**
+ * \file crypt_path.h
+ * \brief Header file for crypt_path.c.
+ **/
+
+#ifndef CRYPT_PATH_H
+#define CRYPT_PATH_H
+
+void cpath_assert_layer_ok(const crypt_path_t *cp);
+
+void cpath_assert_ok(const crypt_path_t *cp);
+
+int cpath_append_hop(crypt_path_t **head_ptr, extend_info_t *choice);
+
+int cpath_init_circuit_crypto(crypt_path_t *cpath,
+                              const char *key_data, size_t key_data_len,
+                              int reverse, int is_hs_v3);
+
+void
+cpath_free(crypt_path_t *victim);
+
+void cpath_extend_linked_list(crypt_path_t **head_ptr, crypt_path_t *new_hop);
+
+void
+cpath_crypt_cell(const crypt_path_t *cpath, uint8_t *payload, bool is_decrypt);
+
+struct crypto_digest_t *
+cpath_get_incoming_digest(const crypt_path_t *cpath);
+
+void cpath_sendme_record_cell_digest(crypt_path_t *cpath,
+                                     bool is_foward_digest);
+
+void
+cpath_set_cell_forward_digest(crypt_path_t *cpath, cell_t *cell);
+
+crypt_path_t *cpath_get_next_non_open_hop(crypt_path_t *cpath);
+
+void cpath_sendme_circuit_record_inbound_cell(crypt_path_t *cpath);
+
+uint8_t *cpath_get_sendme_digest(crypt_path_t *cpath);
+
+#if defined(TOR_UNIT_TESTS)
+unsigned int cpath_get_n_hops(crypt_path_t **head_ptr);
+#endif /* defined(TOR_UNIT_TESTS) */
+
+#endif /* !defined(CRYPT_PATH_H) */
diff --git a/src/core/or/crypt_path_reference_st.h b/src/core/or/crypt_path_reference_st.h
index 3d79f26c1..1827022b4 100644
--- a/src/core/or/crypt_path_reference_st.h
+++ b/src/core/or/crypt_path_reference_st.h
@@ -19,5 +19,5 @@ struct crypt_path_reference_t {
   crypt_path_t *cpath;
 };
 
-#endif
+#endif /* !defined(CRYPT_PATH_REFERENCE_ST_H) */
 
diff --git a/src/core/or/crypt_path_st.h b/src/core/or/crypt_path_st.h
index 429480f8a..249ac6aaa 100644
--- a/src/core/or/crypt_path_st.h
+++ b/src/core/or/crypt_path_st.h
@@ -24,15 +24,24 @@ struct onion_handshake_state_t {
   } u;
 };
 
+/** Macro to encapsulate private members of a struct.
+ *
+ *  Renames 'x' to 'x_crypt_path_private_field'.
+ */
+#define CRYPT_PATH_PRIV_FIELD(x) x ## _crypt_path_private_field
+
+#ifdef CRYPT_PATH_PRIVATE
+
+/* Helper macro to access private members of a struct. */
+#define pvt_crypto CRYPT_PATH_PRIV_FIELD(crypto)
+
+#endif /* defined(CRYPT_PATH_PRIVATE) */
+
 /** Holds accounting information for a single step in the layered encryption
  * performed by a circuit.  Used only at the client edge of a circuit. */
 struct crypt_path_t {
   uint32_t magic;
 
-  /** Cryptographic state used for encrypting and authenticating relay
-   * cells to and from this hop. */
-  relay_crypto_t crypto;
-
   /** Current state of the handshake as performed with the OR at this
    * step. */
   onion_handshake_state_t handshake_state;
@@ -65,6 +74,12 @@ struct crypt_path_t {
                        * at this step? */
   int deliver_window; /**< How many cells are we willing to deliver originating
                        * at this step? */
+
+  /*********************** Private members ****************************/
+
+  /** Private member: Cryptographic state used for encrypting and
+   * authenticating relay cells to and from this hop. */
+  relay_crypto_t CRYPT_PATH_PRIV_FIELD(crypto);
 };
 
-#endif
+#endif /* !defined(CRYPT_PATH_ST_H) */
diff --git a/src/core/or/destroy_cell_queue_st.h b/src/core/or/destroy_cell_queue_st.h
index 56630670b..e917afc70 100644
--- a/src/core/or/destroy_cell_queue_st.h
+++ b/src/core/or/destroy_cell_queue_st.h
@@ -23,5 +23,5 @@ struct destroy_cell_queue_t {
   int n; /**< The number of cells in the queue. */
 };
 
-#endif
+#endif /* !defined(DESTROY_CELL_QUEUE_ST_H) */
 
diff --git a/src/core/or/dos.h b/src/core/or/dos.h
index 95448d053..b5154a7cd 100644
--- a/src/core/or/dos.h
+++ b/src/core/or/dos.h
@@ -134,7 +134,7 @@ MOCK_DECL(STATIC unsigned int, get_param_cc_enabled,
 MOCK_DECL(STATIC unsigned int, get_param_conn_enabled,
           (const networkstatus_t *ns));
 
-#endif /* TOR_DOS_PRIVATE */
+#endif /* defined(DOS_PRIVATE) */
 
-#endif /* TOR_DOS_H */
+#endif /* !defined(TOR_DOS_H) */
 
diff --git a/src/core/or/edge_connection_st.h b/src/core/or/edge_connection_st.h
index 1665b8589..8922a3a9c 100644
--- a/src/core/or/edge_connection_st.h
+++ b/src/core/or/edge_connection_st.h
@@ -73,5 +73,5 @@ struct edge_connection_t {
   uint64_t dirreq_id;
 };
 
-#endif
+#endif /* !defined(EDGE_CONNECTION_ST_H) */
 
diff --git a/src/core/or/entry_connection_st.h b/src/core/or/entry_connection_st.h
index 45621fadb..e65c545d1 100644
--- a/src/core/or/entry_connection_st.h
+++ b/src/core/or/entry_connection_st.h
@@ -96,5 +96,5 @@ struct entry_connection_t {
 /** Cast a entry_connection_t subtype pointer to a edge_connection_t **/
 #define ENTRY_TO_EDGE_CONN(c) (&(((c))->edge_))
 
-#endif
+#endif /* !defined(ENTRY_CONNECTION_ST_H) */
 
diff --git a/src/core/or/entry_port_cfg_st.h b/src/core/or/entry_port_cfg_st.h
index 87dfb331e..b84838d44 100644
--- a/src/core/or/entry_port_cfg_st.h
+++ b/src/core/or/entry_port_cfg_st.h
@@ -50,5 +50,5 @@ struct entry_port_cfg_t {
 
 };
 
-#endif
+#endif /* !defined(ENTRY_PORT_CFG_ST_H) */
 
diff --git a/src/core/or/extend_info_st.h b/src/core/or/extend_info_st.h
index bc7a77b1b..7704ff16b 100644
--- a/src/core/or/extend_info_st.h
+++ b/src/core/or/extend_info_st.h
@@ -27,4 +27,4 @@ struct extend_info_t {
   curve25519_public_key_t curve25519_onion_key;
 };
 
-#endif
+#endif /* !defined(EXTEND_INFO_ST_H) */
diff --git a/src/core/or/half_edge_st.h b/src/core/or/half_edge_st.h
index d4617be10..1fe47ad3f 100644
--- a/src/core/or/half_edge_st.h
+++ b/src/core/or/half_edge_st.h
@@ -30,5 +30,5 @@ typedef struct half_edge_t {
   int connected_pending : 1;
 } half_edge_t;
 
-#endif
+#endif /* !defined(HALF_EDGE_ST_H) */
 
diff --git a/src/core/or/listener_connection_st.h b/src/core/or/listener_connection_st.h
index 8989a39dc..1250d9c9b 100644
--- a/src/core/or/listener_connection_st.h
+++ b/src/core/or/listener_connection_st.h
@@ -21,5 +21,5 @@ struct listener_connection_t {
 
 };
 
-#endif
+#endif /* !defined(LISTENER_CONNECTION_ST_H) */
 
diff --git a/src/core/or/ocirc_event.h b/src/core/or/ocirc_event.h
index 0b125c289..59ec9e27c 100644
--- a/src/core/or/ocirc_event.h
+++ b/src/core/or/ocirc_event.h
@@ -86,4 +86,4 @@ void ocirc_event_subscribe(ocirc_event_rcvr_t fn);
 void ocirc_event_publish(const ocirc_event_msg_t *msg);
 #endif
 
-#endif  /* defined(TOR_OCIRC_EVENT_STATE_H) */
+#endif /* !defined(TOR_OCIRC_EVENT_H) */
diff --git a/src/core/or/ocirc_event_sys.h b/src/core/or/ocirc_event_sys.h
index 9d4bfe533..61180496d 100644
--- a/src/core/or/ocirc_event_sys.h
+++ b/src/core/or/ocirc_event_sys.h
@@ -10,4 +10,4 @@
 
 extern const struct subsys_fns_t sys_ocirc_event;
 
-#endif  /* defined(TOR_OCIRC_EVENT_H) */
+#endif /* !defined(TOR_OCIRC_EVENT_SYS_H) */
diff --git a/src/core/or/or.h b/src/core/or/or.h
index db6d08958..ab258629a 100644
--- a/src/core/or/or.h
+++ b/src/core/or/or.h
@@ -841,8 +841,8 @@ typedef struct protover_summary_flags_t {
   unsigned int supports_v3_rendezvous_point: 1;
 
   /** True iff this router has a protocol list that allows clients to
-   * negotiate link-level padding. Requires Padding>=1. */
-  unsigned int supports_padding : 1;
+   * negotiate hs circuit setup padding. Requires Padding>=2. */
+  unsigned int supports_hs_setup_padding : 1;
 } protover_summary_flags_t;
 
 typedef struct routerinfo_t routerinfo_t;
diff --git a/src/core/or/or_circuit_st.h b/src/core/or/or_circuit_st.h
index 6b6feb9d8..678966822 100644
--- a/src/core/or/or_circuit_st.h
+++ b/src/core/or/or_circuit_st.h
@@ -33,11 +33,6 @@ struct or_circuit_t {
   cell_queue_t p_chan_cells;
   /** The channel that is previous in this circuit. */
   channel_t *p_chan;
-  /**
-   * Circuit mux associated with p_chan to which this circuit is attached;
-   * NULL if we have no p_chan.
-   */
-  circuitmux_t *p_mux;
   /** Linked list of Exit streams associated with this circuit. */
   edge_connection_t *n_streams;
   /** Linked list of Exit streams associated with this circuit that are
@@ -76,5 +71,5 @@ struct or_circuit_t {
   uint64_t total_cell_waiting_time;
 };
 
-#endif
+#endif /* !defined(OR_CIRCUIT_ST_H) */
 
diff --git a/src/core/or/or_connection_st.h b/src/core/or/or_connection_st.h
index a5ce844bf..051fcd00d 100644
--- a/src/core/or/or_connection_st.h
+++ b/src/core/or/or_connection_st.h
@@ -91,4 +91,4 @@ struct or_connection_t {
   uint64_t bytes_xmitted, bytes_xmitted_by_tls;
 };
 
-#endif
+#endif /* !defined(OR_CONNECTION_ST_H) */
diff --git a/src/core/or/or_handshake_certs_st.h b/src/core/or/or_handshake_certs_st.h
index a93b7104a..9deb6d6d5 100644
--- a/src/core/or/or_handshake_certs_st.h
+++ b/src/core/or/or_handshake_certs_st.h
@@ -37,4 +37,4 @@ struct or_handshake_certs_t {
   size_t ed_rsa_crosscert_len;
 };
 
-#endif
+#endif /* !defined(OR_HANDSHAKE_CERTS_ST) */
diff --git a/src/core/or/or_handshake_state_st.h b/src/core/or/or_handshake_state_st.h
index 09a8a3417..472ce8a30 100644
--- a/src/core/or/or_handshake_state_st.h
+++ b/src/core/or/or_handshake_state_st.h
@@ -74,5 +74,5 @@ struct or_handshake_state_t {
   or_handshake_certs_t *certs;
 };
 
-#endif
+#endif /* !defined(OR_HANDSHAKE_STATE_ST) */
 
diff --git a/src/core/or/or_periodic.c b/src/core/or/or_periodic.c
new file mode 100644
index 000000000..fe28c9919
--- /dev/null
+++ b/src/core/or/or_periodic.c
@@ -0,0 +1,65 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file or_periodic.c
+ * @brief Periodic callbacks for the onion routing subsystem
+ **/
+
+#include "orconfig.h"
+#include "core/or/or.h"
+
+#include "core/mainloop/periodic.h"
+
+#include "core/or/channel.h"
+#include "core/or/circuituse.h"
+#include "core/or/or_periodic.h"
+
+#include "feature/relay/routermode.h"
+
+#define DECLARE_EVENT(name, roles, flags)         \
+  static periodic_event_item_t name ## _event =   \
+    PERIODIC_EVENT(name,                          \
+                   PERIODIC_EVENT_ROLE_##roles,   \
+                   flags)
+
+#define FL(name) (PERIODIC_EVENT_FLAG_ ## name)
+
+#define CHANNEL_CHECK_INTERVAL (60*60)
+static int
+check_canonical_channels_callback(time_t now, const or_options_t *options)
+{
+  (void)now;
+  if (public_server_mode(options))
+    channel_check_for_duplicates();
+
+  return CHANNEL_CHECK_INTERVAL;
+}
+
+DECLARE_EVENT(check_canonical_channels, RELAY, FL(NEED_NET));
+
+/**
+ * Periodic callback: as a server, see if we have any old unused circuits
+ * that should be expired */
+static int
+expire_old_circuits_serverside_callback(time_t now,
+                                        const or_options_t *options)
+{
+  (void)options;
+  /* every 11 seconds, so not usually the same second as other such events */
+  circuit_expire_old_circuits_serverside(now);
+  return 11;
+}
+
+DECLARE_EVENT(expire_old_circuits_serverside, ROUTER, FL(NEED_NET));
+
+void
+or_register_periodic_events(void)
+{
+  // These are router-only events, but they're owned by the OR subsystem. */
+  periodic_events_register(&check_canonical_channels_event);
+  periodic_events_register(&expire_old_circuits_serverside_event);
+}
diff --git a/src/core/or/or_periodic.h b/src/core/or/or_periodic.h
new file mode 100644
index 000000000..c2f47cf5e
--- /dev/null
+++ b/src/core/or/or_periodic.h
@@ -0,0 +1,17 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file or_periodic.h
+ * @brief Header for core/or/or_periodic.c
+ **/
+
+#ifndef TOR_CORE_OR_OR_PERIODIC_H
+#define TOR_CORE_OR_OR_PERIODIC_H
+
+void or_register_periodic_events(void);
+
+#endif /* !defined(TOR_CORE_OR_OR_PERIODIC_H) */
diff --git a/src/core/or/or_sys.c b/src/core/or/or_sys.c
new file mode 100644
index 000000000..6f8c81a4d
--- /dev/null
+++ b/src/core/or/or_sys.c
@@ -0,0 +1,43 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file or_sys.c
+ * @brief Subsystem definitions for OR module.
+ **/
+
+#include "orconfig.h"
+#include "core/or/or.h"
+#include "core/or/or_periodic.h"
+#include "core/or/or_sys.h"
+#include "core/or/policies.h"
+#include "core/or/protover.h"
+#include "core/or/versions.h"
+
+#include "lib/subsys/subsys.h"
+
+static int
+subsys_or_initialize(void)
+{
+  or_register_periodic_events();
+  return 0;
+}
+
+static void
+subsys_or_shutdown(void)
+{
+  protover_free_all();
+  protover_summary_cache_free_all();
+  policies_free_all();
+}
+
+const struct subsys_fns_t sys_or = {
+  .name = "or",
+  .supported = true,
+  .level = 20,
+  .initialize = subsys_or_initialize,
+  .shutdown = subsys_or_shutdown,
+};
diff --git a/src/core/or/or_sys.h b/src/core/or/or_sys.h
new file mode 100644
index 000000000..c37ef0185
--- /dev/null
+++ b/src/core/or/or_sys.h
@@ -0,0 +1,17 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file or_sys.h
+ * @brief Header for core/or/or_sys.c
+ **/
+
+#ifndef TOR_CORE_OR_OR_SYS_H
+#define TOR_CORE_OR_OR_SYS_H
+
+extern const struct subsys_fns_t sys_or;
+
+#endif /* !defined(TOR_CORE_OR_OR_SYS_H) */
diff --git a/src/core/or/orconn_event.h b/src/core/or/orconn_event.h
index 80289d53e..d6635793d 100644
--- a/src/core/or/orconn_event.h
+++ b/src/core/or/orconn_event.h
@@ -117,4 +117,4 @@ void orconn_event_subscribe(orconn_event_rcvr_t);
 void orconn_event_publish(const orconn_event_msg_t *);
 #endif
 
-#endif  /* defined(TOR_ORCONN_EVENT_H) */
+#endif /* !defined(TOR_ORCONN_EVENT_H) */
diff --git a/src/core/or/orconn_event_sys.h b/src/core/or/orconn_event_sys.h
index bfb0a3ac4..9703b2e3d 100644
--- a/src/core/or/orconn_event_sys.h
+++ b/src/core/or/orconn_event_sys.h
@@ -9,4 +9,4 @@
 
 extern const struct subsys_fns_t sys_orconn_event;
 
-#endif  /* defined(TOR_ORCONN_SYS_H) */
+#endif /* !defined(TOR_ORCONN_EVENT_SYS_H) */
diff --git a/src/core/or/origin_circuit_st.h b/src/core/or/origin_circuit_st.h
index daa5f41da..01bbc84ae 100644
--- a/src/core/or/origin_circuit_st.h
+++ b/src/core/or/origin_circuit_st.h
@@ -295,4 +295,4 @@ struct origin_circuit_t {
 
 };
 
-#endif
+#endif /* !defined(ORIGIN_CIRCUIT_ST_H) */
diff --git a/src/core/or/policies.c b/src/core/or/policies.c
index a6d66d36d..83d9a53fc 100644
--- a/src/core/or/policies.c
+++ b/src/core/or/policies.c
@@ -31,6 +31,7 @@
 #include "ht.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/encoding/confline.h"
+#include "trunnel/ed25519_cert.h"
 
 #include "core/or/addr_policy_st.h"
 #include "feature/dirclient/dir_server_st.h"
@@ -1015,6 +1016,83 @@ fascist_firewall_choose_address_rs(const routerstatus_t *rs,
   }
 }
 
+/** Like fascist_firewall_choose_address_base(), but takes in a smartlist
+ * <b>lspecs</b> consisting of one or more link specifiers. We assume
+ * fw_connection is FIREWALL_OR_CONNECTION as link specifiers cannot
+ * contain DirPorts.
+ */
+void
+fascist_firewall_choose_address_ls(const smartlist_t *lspecs,
+                                   int pref_only, tor_addr_port_t* ap)
+{
+  int have_v4 = 0, have_v6 = 0;
+  uint16_t port_v4 = 0, port_v6 = 0;
+  tor_addr_t addr_v4, addr_v6;
+
+  tor_assert(ap);
+
+  if (lspecs == NULL) {
+    log_warn(LD_BUG, "Unknown or missing link specifiers");
+    return;
+  }
+  if (smartlist_len(lspecs) == 0) {
+    log_warn(LD_PROTOCOL, "Link specifiers are empty");
+    return;
+  }
+
+  tor_addr_make_null(&ap->addr, AF_UNSPEC);
+  ap->port = 0;
+
+  tor_addr_make_null(&addr_v4, AF_INET);
+  tor_addr_make_null(&addr_v6, AF_INET6);
+
+  SMARTLIST_FOREACH_BEGIN(lspecs, const link_specifier_t *, ls) {
+    switch (link_specifier_get_ls_type(ls)) {
+    case LS_IPV4:
+      /* Skip if we already seen a v4. */
+      if (have_v4) continue;
+      tor_addr_from_ipv4h(&addr_v4,
+                          link_specifier_get_un_ipv4_addr(ls));
+      port_v4 = link_specifier_get_un_ipv4_port(ls);
+      have_v4 = 1;
+      break;
+    case LS_IPV6:
+      /* Skip if we already seen a v6, or deliberately skip it if we're not a
+       * direct connection. */
+      if (have_v6) continue;
+      tor_addr_from_ipv6_bytes(&addr_v6,
+          (const char *) link_specifier_getconstarray_un_ipv6_addr(ls));
+      port_v6 = link_specifier_get_un_ipv6_port(ls);
+      have_v6 = 1;
+      break;
+    default:
+      /* Ignore unknown. */
+      break;
+    }
+  } SMARTLIST_FOREACH_END(ls);
+
+  /* If we don't have IPv4 or IPv6 in link specifiers, log a bug and return. */
+  if (!have_v4 && !have_v6) {
+    if (!have_v6) {
+      log_warn(LD_PROTOCOL, "None of our link specifiers have IPv4 or IPv6");
+    } else {
+      log_warn(LD_PROTOCOL, "None of our link specifiers have IPv4");
+    }
+    return;
+  }
+
+  /* Here, don't check for DirPorts as link specifiers are only used for
+   * ORPorts. */
+  const or_options_t *options = get_options();
+  int pref_ipv6 = fascist_firewall_prefer_ipv6_orport(options);
+  /* Assume that the DirPorts are zero as link specifiers only use ORPorts. */
+  fascist_firewall_choose_address_base(&addr_v4, port_v4, 0,
+                                       &addr_v6, port_v6, 0,
+                                       FIREWALL_OR_CONNECTION,
+                                       pref_only, pref_ipv6,
+                                       ap);
+}
+
 /** Like fascist_firewall_choose_address_base(), but takes <b>node</b>, and
  * looks up the node's IPv6 preference rather than taking an argument
  * for pref_ipv6. */
@@ -1164,6 +1242,15 @@ authdir_policy_badexit_address(uint32_t addr, uint16_t port)
 #define REJECT(arg) \
   STMT_BEGIN *msg = tor_strdup(arg); goto err; STMT_END
 
+/** Check <b>or_options</b> to determine whether or not we are using the
+ * default options for exit policy. Return true if so, false otherwise. */
+static int
+policy_using_default_exit_options(const or_options_t *or_options)
+{
+  return (or_options->ExitPolicy == NULL && or_options->ExitRelay == -1 &&
+          or_options->ReducedExitPolicy == 0 && or_options->IPv6Exit == 0);
+}
+
 /** Config helper: If there's any problem with the policy configuration
  * options in <b>options</b>, return -1 and set <b>msg</b> to a newly
  * allocated description of the error. Else return 0. */
@@ -1182,9 +1269,8 @@ validate_addr_policies(const or_options_t *options, char **msg)
 
   static int warned_about_nonexit = 0;
 
-  if (public_server_mode(options) &&
-      !warned_about_nonexit && options->ExitPolicy == NULL &&
-      options->ExitRelay == -1 && options->ReducedExitPolicy == 0) {
+  if (public_server_mode(options) && !warned_about_nonexit &&
+      policy_using_default_exit_options(options)) {
     warned_about_nonexit = 1;
     log_notice(LD_CONFIG, "By default, Tor does not run as an exit relay. "
                "If you want to be an exit relay, "
@@ -2141,9 +2227,9 @@ policies_parse_exit_policy_from_options(const or_options_t *or_options,
   int rv = 0;
 
   /* Short-circuit for non-exit relays, or for relays where we didn't specify
-   * ExitPolicy or ReducedExitPolicy and ExitRelay is auto. */
-  if (or_options->ExitRelay == 0 || (or_options->ExitPolicy == NULL &&
-      or_options->ExitRelay == -1 && or_options->ReducedExitPolicy == 0)) {
+   * ExitPolicy or ReducedExitPolicy or IPv6Exit and ExitRelay is auto. */
+  if (or_options->ExitRelay == 0 ||
+      policy_using_default_exit_options(or_options)) {
     append_exit_policy_string(result, "reject *4:*");
     append_exit_policy_string(result, "reject *6:*");
     return 0;
diff --git a/src/core/or/policies.h b/src/core/or/policies.h
index 324c1c2dd..3c46363c0 100644
--- a/src/core/or/policies.h
+++ b/src/core/or/policies.h
@@ -92,6 +92,8 @@ int fascist_firewall_allows_dir_server(const dir_server_t *ds,
 void fascist_firewall_choose_address_rs(const routerstatus_t *rs,
                                         firewall_connection_t fw_connection,
                                         int pref_only, tor_addr_port_t* ap);
+void fascist_firewall_choose_address_ls(const smartlist_t *lspecs,
+                                        int pref_only, tor_addr_port_t* ap);
 void fascist_firewall_choose_address_node(const node_t *node,
                                           firewall_connection_t fw_connection,
                                           int pref_only, tor_addr_port_t* ap);
diff --git a/src/core/or/port_cfg_st.h b/src/core/or/port_cfg_st.h
index b67091ce3..e9e82bb1d 100644
--- a/src/core/or/port_cfg_st.h
+++ b/src/core/or/port_cfg_st.h
@@ -31,5 +31,5 @@ struct port_cfg_t {
   char unix_addr[FLEXIBLE_ARRAY_MEMBER];
 };
 
-#endif
+#endif /* !defined(PORT_CFG_ST_H) */
 
diff --git a/src/core/or/protover.c b/src/core/or/protover.c
index 53709ad00..ccd33fabf 100644
--- a/src/core/or/protover.c
+++ b/src/core/or/protover.c
@@ -53,7 +53,8 @@ static const struct {
   { PRT_DESC, "Desc" },
   { PRT_MICRODESC, "Microdesc"},
   { PRT_PADDING, "Padding"},
-  { PRT_CONS, "Cons" }
+  { PRT_CONS, "Cons" },
+  { PRT_FLOWCTRL, "FlowCtrl"},
 };
 
 #define N_PROTOCOL_NAMES ARRAY_LENGTH(PROTOCOL_NAMES)
@@ -401,7 +402,8 @@ protover_get_supported_protocols(void)
 #endif
     "Microdesc=1-2 "
     "Relay=1-2 "
-    "Padding=1";
+    "Padding=2 "
+    "FlowCtrl=1";
 }
 
 /** The protocols from protover_get_supported_protocols(), as parsed into a
@@ -820,6 +822,8 @@ protover_all_supported(const char *s, char **missing_out)
        * ones and, if so, add them to unsupported->ranges. */
       if (versions->low != 0 && versions->high != 0) {
         smartlist_add(unsupported->ranges, versions);
+      } else {
+        tor_free(versions);
       }
       /* Finally, if we had something unsupported, add it to the list of
        * missing_some things and mark that there was something missing. */
@@ -828,7 +832,6 @@ protover_all_supported(const char *s, char **missing_out)
         all_supported = 0;
       } else {
         proto_entry_free(unsupported);
-        tor_free(versions);
       }
     } SMARTLIST_FOREACH_END(range);
 
diff --git a/src/core/or/protover.h b/src/core/or/protover.h
index 567b94a16..af45a31ae 100644
--- a/src/core/or/protover.h
+++ b/src/core/or/protover.h
@@ -28,6 +28,8 @@ struct smartlist_t;
 #define PROTOVER_HS_INTRO_V3 4
 /** The protover version number that signifies HSv3 rendezvous point support */
 #define PROTOVER_HS_RENDEZVOUS_POINT_V3 2
+/** The protover that signals support for HS circuit setup padding machines */
+#define PROTOVER_HS_SETUP_PADDING 2
 
 /** List of recognized subprotocols. */
 /// C_RUST_COUPLED: src/rust/protover/ffi.rs `translate_to_rust`
@@ -44,6 +46,7 @@ typedef enum protocol_type_t {
   PRT_MICRODESC = 8,
   PRT_CONS      = 9,
   PRT_PADDING   = 10,
+  PRT_FLOWCTRL  = 11,
 } protocol_type_t;
 
 bool protover_contains_long_protocol_names(const char *s);
diff --git a/src/core/or/relay.c b/src/core/or/relay.c
index 706a6e05c..9e691a02b 100644
--- a/src/core/or/relay.c
+++ b/src/core/or/relay.c
@@ -61,7 +61,7 @@
 #include "core/mainloop/connection.h"
 #include "core/or/connection_edge.h"
 #include "core/or/connection_or.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/crypt_ops/crypto_util.h"
 #include "feature/dircommon/directory.h"
@@ -93,15 +93,12 @@
 #include "core/or/origin_circuit_st.h"
 #include "feature/nodelist/routerinfo_st.h"
 #include "core/or/socks_request_st.h"
-
-#include "lib/intmath/weakrng.h"
+#include "core/or/sendme.h"
 
 static edge_connection_t *relay_lookup_conn(circuit_t *circ, cell_t *cell,
                                             cell_direction_t cell_direction,
                                             crypt_path_t *layer_hint);
 
-static void circuit_consider_sending_sendme(circuit_t *circ,
-                                            crypt_path_t *layer_hint);
 static void circuit_resume_edge_reading(circuit_t *circ,
                                         crypt_path_t *layer_hint);
 static int circuit_resume_edge_reading_helper(edge_connection_t *conn,
@@ -134,9 +131,6 @@ uint64_t stats_n_relay_cells_delivered = 0;
  * reached (see append_cell_to_circuit_queue()) */
 uint64_t stats_n_circ_max_cell_reached = 0;
 
-/** Used to tell which stream to read from first on a circuit. */
-static tor_weak_rng_t stream_choice_rng = TOR_WEAK_RNG_INIT;
-
 /**
  * Update channel usage state based on the type of relay cell and
  * circuit properties.
@@ -253,6 +247,10 @@ circuit_receive_relay_cell(cell_t *cell, circuit_t *circ,
   if (recognized) {
     edge_connection_t *conn = NULL;
 
+    /* Recognized cell, the cell digest has been updated, we'll record it for
+     * the SENDME if need be. */
+    sendme_record_received_cell_digest(circ, layer_hint);
+
     if (circ->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING) {
       if (pathbias_check_probe_response(circ, cell) == -1) {
         pathbias_count_valid_cells(circ, cell);
@@ -535,6 +533,64 @@ relay_command_to_string(uint8_t command)
   }
 }
 
+/** When padding a cell with randomness, leave this many zeros after the
+ * payload. */
+#define CELL_PADDING_GAP 4
+
+/** Return the offset where the padding should start. The <b>data_len</b> is
+ * the relay payload length expected to be put in the cell. It can not be
+ * bigger than RELAY_PAYLOAD_SIZE else this function assert().
+ *
+ * Value will always be smaller than CELL_PAYLOAD_SIZE because this offset is
+ * for the entire cell length not just the data payload length. Zero is
+ * returned if there is no room for padding.
+ *
+ * This function always skips the first 4 bytes after the payload because
+ * having some unused zero bytes has saved us a lot of times in the past. */
+
+STATIC size_t
+get_pad_cell_offset(size_t data_len)
+{
+  /* This is never supposed to happen but in case it does, stop right away
+   * because if tor is tricked somehow into not adding random bytes to the
+   * payload with this function returning 0 for a bad data_len, the entire
+   * authenticated SENDME design can be bypassed leading to bad denial of
+   * service attacks. */
+  tor_assert(data_len <= RELAY_PAYLOAD_SIZE);
+
+  /* If the offset is larger than the cell payload size, we return an offset
+   * of zero indicating that no padding needs to be added. */
+  size_t offset = RELAY_HEADER_SIZE + data_len + CELL_PADDING_GAP;
+  if (offset >= CELL_PAYLOAD_SIZE) {
+    return 0;
+  }
+  return offset;
+}
+
+/* Add random bytes to the unused portion of the payload, to foil attacks
+ * where the other side can predict all of the bytes in the payload and thus
+ * compute the authenticated SENDME cells without seeing the traffic. See
+ * proposal 289. */
+static void
+pad_cell_payload(uint8_t *cell_payload, size_t data_len)
+{
+  size_t pad_offset, pad_len;
+
+  tor_assert(cell_payload);
+
+  pad_offset = get_pad_cell_offset(data_len);
+  if (pad_offset == 0) {
+    /* We can't add padding so we are done. */
+    return;
+  }
+
+  /* Remember here that the cell_payload is the length of the header and
+   * payload size so we offset it using the full length of the cell. */
+  pad_len = CELL_PAYLOAD_SIZE - pad_offset;
+  crypto_fast_rng_getbytes(get_thread_fast_rng(),
+                           cell_payload + pad_offset, pad_len);
+}
+
 /** Make a relay cell out of <b>relay_command</b> and <b>payload</b>, and send
  * it onto the open circuit <b>circ</b>. <b>stream_id</b> is the ID on
  * <b>circ</b> for the stream that's sending the relay cell, or 0 if it's a
@@ -578,6 +634,9 @@ relay_send_command_from_edge_,(streamid_t stream_id, circuit_t *circ,
   if (payload_len)
     memcpy(cell.payload+RELAY_HEADER_SIZE, payload, payload_len);
 
+  /* Add random padding to the cell if we can. */
+  pad_cell_payload(cell.payload, payload_len);
+
   log_debug(LD_OR,"delivering %d cell %s.", relay_command,
             cell_direction == CELL_DIRECTION_OUT ? "forward" : "backward");
 
@@ -645,6 +704,14 @@ relay_send_command_from_edge_,(streamid_t stream_id, circuit_t *circ,
     circuit_mark_for_close(circ, END_CIRC_REASON_INTERNAL);
     return -1;
   }
+
+  /* If applicable, note the cell digest for the SENDME version 1 purpose if
+   * we need to. This call needs to be after the circuit_package_relay_cell()
+   * because the cell digest is set within that function. */
+  if (relay_command == RELAY_COMMAND_DATA) {
+    sendme_record_cell_digest_on_circ(circ, cpath_layer);
+  }
+
   return 0;
 }
 
@@ -1434,6 +1501,81 @@ connection_edge_process_relay_cell_not_open(
 //  return -1;
 }
 
+/** Process a SENDME cell that arrived on <b>circ</b>. If it is a stream level
+ * cell, it is destined for the given <b>conn</b>. If it is a circuit level
+ * cell, it is destined for the <b>layer_hint</b>. The <b>domain</b> is the
+ * logging domain that should be used.
+ *
+ * Return 0 if everything went well or a negative value representing a circuit
+ * end reason on error for which the caller is responsible for closing it. */
+static int
+process_sendme_cell(const relay_header_t *rh, const cell_t *cell,
+                    circuit_t *circ, edge_connection_t *conn,
+                    crypt_path_t *layer_hint, int domain)
+{
+  int ret;
+
+  tor_assert(rh);
+
+  if (!rh->stream_id) {
+    /* Circuit level SENDME cell. */
+    ret = sendme_process_circuit_level(layer_hint, circ,
+                                       cell->payload + RELAY_HEADER_SIZE,
+                                       rh->length);
+    if (ret < 0) {
+      return ret;
+    }
+    /* Resume reading on any streams now that we've processed a valid
+     * SENDME cell that updated our package window. */
+    circuit_resume_edge_reading(circ, layer_hint);
+    /* We are done, the rest of the code is for the stream level. */
+    return 0;
+  }
+
+  /* No connection, might be half edge state. We are done if so. */
+  if (!conn) {
+    if (CIRCUIT_IS_ORIGIN(circ)) {
+      origin_circuit_t *ocirc = TO_ORIGIN_CIRCUIT(circ);
+      if (connection_half_edge_is_valid_sendme(ocirc->half_streams,
+                                               rh->stream_id)) {
+        circuit_read_valid_data(ocirc, rh->length);
+        log_info(domain, "Sendme cell on circ %u valid on half-closed "
+                         "stream id %d",
+                 ocirc->global_identifier, rh->stream_id);
+      }
+    }
+
+    log_info(domain, "SENDME cell dropped, unknown stream (streamid %d).",
+             rh->stream_id);
+    return 0;
+  }
+
+  /* Stream level SENDME cell. */
+  ret = sendme_process_stream_level(conn, circ, rh->length);
+  if (ret < 0) {
+    /* Means we need to close the circuit with reason ret. */
+    return ret;
+  }
+
+  /* We've now processed properly a SENDME cell, all windows have been
+   * properly updated, we'll read on the edge connection to see if we can
+   * get data out towards the end point (Exit or client) since we are now
+   * allowed to deliver more cells. */
+
+  if (circuit_queue_streams_are_blocked(circ)) {
+    /* Still waiting for queue to flush; don't touch conn */
+    return 0;
+  }
+  connection_start_reading(TO_CONN(conn));
+  /* handle whatever might still be on the inbuf */
+  if (connection_edge_package_raw_inbuf(conn, 1, NULL) < 0) {
+    /* (We already sent an end cell if possible) */
+    connection_mark_for_close(TO_CONN(conn));
+    return 0;
+  }
+  return 0;
+}
+
 /** An incoming relay cell has arrived on circuit <b>circ</b>. If
  * <b>conn</b> is NULL this is a control cell, else <b>cell</b> is
  * destined for <b>conn</b>.
@@ -1487,7 +1629,7 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
     }
   }
 
-  /* Tell circpad that we've recieved a recognized cell */
+  /* Tell circpad that we've received a recognized cell */
   circpad_deliver_recognized_relay_cell_events(circ, rh.command, layer_hint);
 
   /* either conn is NULL, in which case we've got a control cell, or else
@@ -1521,6 +1663,17 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
       if (circpad_handle_padding_negotiated(circ, cell, layer_hint) == 0)
         circuit_read_valid_data(TO_ORIGIN_CIRCUIT(circ), rh.length);
       return 0;
+  }
+
+  /* If this is a padding circuit we don't need to parse any other commands
+   * than the padding ones. Just drop them to the floor. */
+  if (circ->purpose == CIRCUIT_PURPOSE_C_CIRCUIT_PADDING) {
+    log_info(domain, "Ignored cell (%d) that arrived in padding circuit.",
+             rh.command);
+    return 0;
+  }
+
+  switch (rh.command) {
     case RELAY_COMMAND_BEGIN:
     case RELAY_COMMAND_BEGIN_DIR:
       if (layer_hint &&
@@ -1554,22 +1707,19 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
       return connection_exit_begin_conn(cell, circ);
     case RELAY_COMMAND_DATA:
       ++stats_n_data_cells_received;
-      if (( layer_hint && --layer_hint->deliver_window < 0) ||
-          (!layer_hint && --circ->deliver_window < 0)) {
+
+      /* Update our circuit-level deliver window that we received a DATA cell.
+       * If the deliver window goes below 0, we end the circuit and stream due
+       * to a protocol failure. */
+      if (sendme_circuit_data_received(circ, layer_hint) < 0) {
         log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
                "(relay data) circ deliver_window below 0. Killing.");
-        if (conn) {
-          /* XXXX Do we actually need to do this?  Will killing the circuit
-           * not send an END and mark the stream for close as appropriate? */
-          connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL);
-          connection_mark_for_close(TO_CONN(conn));
-        }
+        connection_edge_end_close(conn, END_STREAM_REASON_TORPROTOCOL);
         return -END_CIRC_REASON_TORPROTOCOL;
       }
-      log_debug(domain,"circ deliver_window now %d.", layer_hint ?
-                layer_hint->deliver_window : circ->deliver_window);
 
-      circuit_consider_sending_sendme(circ, layer_hint);
+      /* Consider sending a circuit-level SENDME cell. */
+      sendme_circuit_consider_sending(circ, layer_hint);
 
       if (rh.stream_id == 0) {
         log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Relay data cell with zero "
@@ -1592,9 +1742,14 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
         return 0;
       }
 
-      if (--conn->deliver_window < 0) { /* is it below 0 after decrement? */
+      /* Update our stream-level deliver window that we just received a DATA
+       * cell. Going below 0 means we have a protocol level error so the
+       * stream and circuit are closed. */
+
+      if (sendme_stream_data_received(conn) < 0) {
         log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
                "(relay data) conn deliver_window below 0. Killing.");
+        connection_edge_end_close(conn, END_STREAM_REASON_TORPROTOCOL);
         return -END_CIRC_REASON_TORPROTOCOL;
       }
       /* Total all valid application bytes delivered */
@@ -1620,7 +1775,7 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
         /* Only send a SENDME if we're not getting optimistic data; otherwise
          * a SENDME could arrive before the CONNECTED.
          */
-        connection_edge_consider_sending_sendme(conn);
+        sendme_connection_edge_consider_sending(conn);
       }
 
       return 0;
@@ -1813,99 +1968,7 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
                (unsigned)circ->n_circ_id, rh.stream_id);
       return 0;
     case RELAY_COMMAND_SENDME:
-      if (!rh.stream_id) {
-        if (layer_hint) {
-          if (layer_hint->package_window + CIRCWINDOW_INCREMENT >
-                CIRCWINDOW_START_MAX) {
-            static struct ratelim_t exit_warn_ratelim = RATELIM_INIT(600);
-            log_fn_ratelim(&exit_warn_ratelim, LOG_WARN, LD_PROTOCOL,
-                   "Unexpected sendme cell from exit relay. "
-                   "Closing circ.");
-            return -END_CIRC_REASON_TORPROTOCOL;
-          }
-          layer_hint->package_window += CIRCWINDOW_INCREMENT;
-          log_debug(LD_APP,"circ-level sendme at origin, packagewindow %d.",
-                    layer_hint->package_window);
-          circuit_resume_edge_reading(circ, layer_hint);
-
-          /* We count circuit-level sendme's as valid delivered data because
-           * they are rate limited.
-           */
-          if (CIRCUIT_IS_ORIGIN(circ)) {
-            circuit_read_valid_data(TO_ORIGIN_CIRCUIT(circ),
-                                    rh.length);
-          }
-
-        } else {
-          if (circ->package_window + CIRCWINDOW_INCREMENT >
-                CIRCWINDOW_START_MAX) {
-            static struct ratelim_t client_warn_ratelim = RATELIM_INIT(600);
-            log_fn_ratelim(&client_warn_ratelim,LOG_PROTOCOL_WARN, LD_PROTOCOL,
-                   "Unexpected sendme cell from client. "
-                   "Closing circ (window %d).",
-                   circ->package_window);
-            return -END_CIRC_REASON_TORPROTOCOL;
-          }
-          circ->package_window += CIRCWINDOW_INCREMENT;
-          log_debug(LD_APP,
-                    "circ-level sendme at non-origin, packagewindow %d.",
-                    circ->package_window);
-          circuit_resume_edge_reading(circ, layer_hint);
-        }
-        return 0;
-      }
-      if (!conn) {
-        if (CIRCUIT_IS_ORIGIN(circ)) {
-          origin_circuit_t *ocirc = TO_ORIGIN_CIRCUIT(circ);
-          if (connection_half_edge_is_valid_sendme(ocirc->half_streams,
-                                                   rh.stream_id)) {
-            circuit_read_valid_data(ocirc, rh.length);
-            log_info(domain,
-                    "sendme cell on circ %u valid on half-closed "
-                    "stream id %d", ocirc->global_identifier, rh.stream_id);
-          }
-        }
-
-        log_info(domain,"sendme cell dropped, unknown stream (streamid %d).",
-                 rh.stream_id);
-        return 0;
-      }
-
-      /* Don't allow the other endpoint to request more than our maximum
-       * (i.e. initial) stream SENDME window worth of data. Well-behaved
-       * stock clients will not request more than this max (as per the check
-       * in the while loop of connection_edge_consider_sending_sendme()).
-       */
-      if (conn->package_window + STREAMWINDOW_INCREMENT >
-          STREAMWINDOW_START_MAX) {
-        static struct ratelim_t stream_warn_ratelim = RATELIM_INIT(600);
-        log_fn_ratelim(&stream_warn_ratelim, LOG_PROTOCOL_WARN, LD_PROTOCOL,
-               "Unexpected stream sendme cell. Closing circ (window %d).",
-               conn->package_window);
-        return -END_CIRC_REASON_TORPROTOCOL;
-      }
-
-      /* At this point, the stream sendme is valid */
-      if (CIRCUIT_IS_ORIGIN(circ)) {
-        circuit_read_valid_data(TO_ORIGIN_CIRCUIT(circ),
-                                rh.length);
-      }
-
-      conn->package_window += STREAMWINDOW_INCREMENT;
-      log_debug(domain,"stream-level sendme, packagewindow now %d.",
-                conn->package_window);
-      if (circuit_queue_streams_are_blocked(circ)) {
-        /* Still waiting for queue to flush; don't touch conn */
-        return 0;
-      }
-      connection_start_reading(TO_CONN(conn));
-      /* handle whatever might still be on the inbuf */
-      if (connection_edge_package_raw_inbuf(conn, 1, NULL) < 0) {
-        /* (We already sent an end cell if possible) */
-        connection_mark_for_close(TO_CONN(conn));
-        return 0;
-      }
-      return 0;
+      return process_sendme_cell(&rh, cell, circ, conn, layer_hint, domain);
     case RELAY_COMMAND_RESOLVE:
       if (layer_hint) {
         log_fn(LOG_PROTOCOL_WARN, LD_APP,
@@ -1979,6 +2042,84 @@ uint64_t stats_n_data_cells_received = 0;
  * ever received were completely full of data. */
 uint64_t stats_n_data_bytes_received = 0;
 
+/**
+ * Called when initializing a circuit, or when we have reached the end of the
+ * window in which we need to send some randomness so that incoming sendme
+ * cells will be unpredictable.  Resets the flags and picks a new window.
+ */
+void
+circuit_reset_sendme_randomness(circuit_t *circ)
+{
+  circ->have_sent_sufficiently_random_cell = 0;
+  circ->send_randomness_after_n_cells = CIRCWINDOW_INCREMENT / 2 +
+    crypto_fast_rng_get_uint(get_thread_fast_rng(), CIRCWINDOW_INCREMENT / 2);
+}
+
+/**
+ * Any relay data payload containing fewer than this many real bytes is
+ * considered to have enough randomness to.
+ **/
+#define RELAY_PAYLOAD_LENGTH_FOR_RANDOM_SENDMES \
+  (RELAY_PAYLOAD_SIZE - CELL_PADDING_GAP - 16)
+
+/**
+ * Helper. Return the number of bytes that should be put into a cell from a
+ * given edge connection on which <b>n_available</b> bytes are available.
+ */
+STATIC size_t
+connection_edge_get_inbuf_bytes_to_package(size_t n_available,
+                                           int package_partial,
+                                           circuit_t *on_circuit)
+{
+  if (!n_available)
+    return 0;
+
+  /* Do we need to force this payload to have space for randomness? */
+  const bool force_random_bytes =
+    (on_circuit->send_randomness_after_n_cells == 0) &&
+    (! on_circuit->have_sent_sufficiently_random_cell);
+
+  /* At most how much would we like to send in this cell? */
+  size_t target_length;
+  if (force_random_bytes) {
+    target_length = RELAY_PAYLOAD_LENGTH_FOR_RANDOM_SENDMES;
+  } else {
+    target_length = RELAY_PAYLOAD_SIZE;
+  }
+
+  /* Decide how many bytes we will actually put into this cell. */
+  size_t package_length;
+  if (n_available >= target_length) { /* A full payload is available. */
+    package_length = target_length;
+  } else { /* not a full payload available */
+    if (package_partial)
+      package_length = n_available; /* just take whatever's available now */
+    else
+      return 0; /* nothing to do until we have a full payload */
+  }
+
+  /* If we reach this point, we will be definitely sending the cell. */
+  tor_assert_nonfatal(package_length > 0);
+
+  if (package_length <= RELAY_PAYLOAD_LENGTH_FOR_RANDOM_SENDMES) {
+    /* This cell will have enough randomness in the padding to make a future
+     * sendme cell unpredictable. */
+    on_circuit->have_sent_sufficiently_random_cell = 1;
+  }
+
+  if (on_circuit->send_randomness_after_n_cells == 0) {
+    /* Either this cell, or some previous cell, had enough padding to
+     * ensure sendme unpredictability. */
+    tor_assert_nonfatal(on_circuit->have_sent_sufficiently_random_cell);
+    /* Pick a new interval in which we need to send randomness. */
+    circuit_reset_sendme_randomness(on_circuit);
+  }
+
+  --on_circuit->send_randomness_after_n_cells;
+
+  return package_length;
+}
+
 /** If <b>conn</b> has an entire relay payload of bytes on its inbuf (or
  * <b>package_partial</b> is true), and the appropriate package windows aren't
  * empty, grab a cell and send it down the circuit.
@@ -2051,17 +2192,14 @@ connection_edge_package_raw_inbuf(edge_connection_t *conn, int package_partial,
     bytes_to_process = connection_get_inbuf_len(TO_CONN(conn));
   }
 
-  if (!bytes_to_process)
+  length = connection_edge_get_inbuf_bytes_to_package(bytes_to_process,
+                                                      package_partial, circ);
+  if (!length)
     return 0;
 
-  if (!package_partial && bytes_to_process < RELAY_PAYLOAD_SIZE)
-    return 0;
+  /* If we reach this point, we will definitely be packaging bytes into
+   * a cell. */
 
-  if (bytes_to_process > RELAY_PAYLOAD_SIZE) {
-    length = RELAY_PAYLOAD_SIZE;
-  } else {
-    length = bytes_to_process;
-  }
   stats_n_data_bytes_packaged += length;
   stats_n_data_cells_packaged += 1;
 
@@ -2096,15 +2234,17 @@ connection_edge_package_raw_inbuf(edge_connection_t *conn, int package_partial,
     return 0;
   }
 
-  if (!cpath_layer) { /* non-rendezvous exit */
-    tor_assert(circ->package_window > 0);
-    circ->package_window--;
-  } else { /* we're an AP, or an exit on a rendezvous circ */
-    tor_assert(cpath_layer->package_window > 0);
-    cpath_layer->package_window--;
+  /* Handle the circuit-level SENDME package window. */
+  if (sendme_note_circuit_data_packaged(circ, cpath_layer) < 0) {
+    /* Package window has gone under 0. Protocol issue. */
+    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+           "Circuit package window is below 0. Closing circuit.");
+    conn->end_reason = END_STREAM_REASON_TORPROTOCOL;
+    return -1;
   }
 
-  if (--conn->package_window <= 0) { /* is it 0 after decrement? */
+  /* Handle the stream-level SENDME package window. */
+  if (sendme_note_stream_data_packaged(conn) < 0) {
     connection_stop_reading(TO_CONN(conn));
     log_debug(domain,"conn->package_window reached 0.");
     circuit_consider_stop_edge_reading(circ, cpath_layer);
@@ -2122,42 +2262,6 @@ connection_edge_package_raw_inbuf(edge_connection_t *conn, int package_partial,
   goto repeat_connection_edge_package_raw_inbuf;
 }
 
-/** Called when we've just received a relay data cell, when
- * we've just finished flushing all bytes to stream <b>conn</b>,
- * or when we've flushed *some* bytes to the stream <b>conn</b>.
- *
- * If conn->outbuf is not too full, and our deliver window is
- * low, send back a suitable number of stream-level sendme cells.
- */
-void
-connection_edge_consider_sending_sendme(edge_connection_t *conn)
-{
-  circuit_t *circ;
-
-  if (connection_outbuf_too_full(TO_CONN(conn)))
-    return;
-
-  circ = circuit_get_by_edge_conn(conn);
-  if (!circ) {
-    /* this can legitimately happen if the destroy has already
-     * arrived and torn down the circuit */
-    log_info(LD_APP,"No circuit associated with conn. Skipping.");
-    return;
-  }
-
-  while (conn->deliver_window <= STREAMWINDOW_START - STREAMWINDOW_INCREMENT) {
-    log_debug(conn->base_.type == CONN_TYPE_AP ?LD_APP:LD_EXIT,
-              "Outbuf %d, Queuing stream sendme.",
-              (int)conn->base_.outbuf_flushlen);
-    conn->deliver_window += STREAMWINDOW_INCREMENT;
-    if (connection_edge_send_command(conn, RELAY_COMMAND_SENDME,
-                                     NULL, 0) < 0) {
-      log_warn(LD_APP,"connection_edge_send_command failed. Skipping.");
-      return; /* the circuit's closed, don't continue */
-    }
-  }
-}
-
 /** The circuit <b>circ</b> has received a circuit-level sendme
  * (on hop <b>layer_hint</b>, if we're the OP). Go through all the
  * attached streams and let them resume reading and packaging, if
@@ -2180,12 +2284,6 @@ circuit_resume_edge_reading(circuit_t *circ, crypt_path_t *layer_hint)
                                        circ, layer_hint);
 }
 
-void
-stream_choice_seed_weak_rng(void)
-{
-  crypto_seed_weak_rng(&stream_choice_rng);
-}
-
 /** A helper function for circuit_resume_edge_reading() above.
  * The arguments are the same, except that <b>conn</b> is the head
  * of a linked list of edge streams that should each be considered.
@@ -2237,7 +2335,8 @@ circuit_resume_edge_reading_helper(edge_connection_t *first_conn,
     int num_streams = 0;
     for (conn = first_conn; conn; conn = conn->next_stream) {
       num_streams++;
-      if (tor_weak_random_one_in_n(&stream_choice_rng, num_streams)) {
+
+      if (crypto_fast_rng_one_in_n(get_thread_fast_rng(), num_streams)) {
         chosen_stream = conn;
       }
       /* Invariant: chosen_stream has been chosen uniformly at random from
@@ -2379,33 +2478,6 @@ circuit_consider_stop_edge_reading(circuit_t *circ, crypt_path_t *layer_hint)
   return 0;
 }
 
-/** Check if the deliver_window for circuit <b>circ</b> (at hop
- * <b>layer_hint</b> if it's defined) is low enough that we should
- * send a circuit-level sendme back down the circuit. If so, send
- * enough sendmes that the window would be overfull if we sent any
- * more.
- */
-static void
-circuit_consider_sending_sendme(circuit_t *circ, crypt_path_t *layer_hint)
-{
-//  log_fn(LOG_INFO,"Considering: layer_hint is %s",
-//         layer_hint ? "defined" : "null");
-  while ((layer_hint ? layer_hint->deliver_window : circ->deliver_window) <=
-          CIRCWINDOW_START - CIRCWINDOW_INCREMENT) {
-    log_debug(LD_CIRC,"Queuing circuit sendme.");
-    if (layer_hint)
-      layer_hint->deliver_window += CIRCWINDOW_INCREMENT;
-    else
-      circ->deliver_window += CIRCWINDOW_INCREMENT;
-    if (relay_send_command_from_edge(0, circ, RELAY_COMMAND_SENDME,
-                                     NULL, 0, layer_hint) < 0) {
-      log_warn(LD_CIRC,
-               "relay_send_command_from_edge failed. Circuit's closed.");
-      return; /* the circuit's closed, don't continue */
-    }
-  }
-}
-
 /** The total number of cells we have allocated. */
 static size_t total_cells_allocated = 0;
 
@@ -2780,7 +2852,7 @@ set_streams_blocked_on_circ(circuit_t *circ, channel_t *chan,
 }
 
 /** Extract the command from a packed cell. */
-static uint8_t
+uint8_t
 packed_cell_get_command(const packed_cell_t *cell, int wide_circ_ids)
 {
   if (wide_circ_ids) {
diff --git a/src/core/or/relay.h b/src/core/or/relay.h
index 044f6be15..79036f97b 100644
--- a/src/core/or/relay.h
+++ b/src/core/or/relay.h
@@ -42,6 +42,7 @@ int connection_edge_package_raw_inbuf(edge_connection_t *conn,
                                       int package_partial,
                                       int *max_cells);
 void connection_edge_consider_sending_sendme(edge_connection_t *conn);
+void circuit_reset_sendme_randomness(circuit_t *circ);
 
 extern uint64_t stats_n_data_cells_packaged;
 extern uint64_t stats_n_data_bytes_packaged;
@@ -94,9 +95,8 @@ const uint8_t *decode_address_from_payload(tor_addr_t *addr_out,
                                         int payload_len);
 void circuit_clear_cell_queue(circuit_t *circ, channel_t *chan);
 
-void stream_choice_seed_weak_rng(void);
-
 circid_t packed_cell_get_circid(const packed_cell_t *cell, int wide_circ_ids);
+uint8_t packed_cell_get_command(const packed_cell_t *cell, int wide_circ_ids);
 
 #ifdef RELAY_PRIVATE
 STATIC int connected_cell_parse(const relay_header_t *rh, const cell_t *cell,
@@ -122,8 +122,11 @@ STATIC int cell_queues_check_size(void);
 STATIC int connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
                                    edge_connection_t *conn,
                                    crypt_path_t *layer_hint);
+STATIC size_t get_pad_cell_offset(size_t payload_len);
+STATIC size_t connection_edge_get_inbuf_bytes_to_package(size_t n_available,
+                                                      int package_partial,
+                                                      circuit_t *on_circuit);
 
 #endif /* defined(RELAY_PRIVATE) */
 
 #endif /* !defined(TOR_RELAY_H) */
-
diff --git a/src/core/or/relay_crypto_st.h b/src/core/or/relay_crypto_st.h
index dafce257c..83bbd329a 100644
--- a/src/core/or/relay_crypto_st.h
+++ b/src/core/or/relay_crypto_st.h
@@ -25,7 +25,9 @@ struct relay_crypto_t {
   /** Digest state for cells heading away from the OR at this step. */
   struct crypto_digest_t *b_digest;
 
+  /** Digest used for the next SENDME cell if any. */
+  uint8_t sendme_digest[DIGEST_LEN];
 };
 #undef crypto_cipher_t
 
-#endif
+#endif /* !defined(RELAY_CRYPTO_ST_H) */
diff --git a/src/core/or/sendme.c b/src/core/or/sendme.c
new file mode 100644
index 000000000..47ac95f3c
--- /dev/null
+++ b/src/core/or/sendme.c
@@ -0,0 +1,710 @@
+/* Copyright (c) 2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file sendme.c
+ * \brief Code that is related to SENDME cells both in terms of
+ *        creating/parsing cells and handling the content.
+ */
+
+#define SENDME_PRIVATE
+
+#include "core/or/or.h"
+
+#include "app/config/config.h"
+#include "core/crypto/relay_crypto.h"
+#include "core/mainloop/connection.h"
+#include "core/or/cell_st.h"
+#include "core/or/crypt_path.h"
+#include "core/or/circuitlist.h"
+#include "core/or/circuituse.h"
+#include "core/or/or_circuit_st.h"
+#include "core/or/relay.h"
+#include "core/or/sendme.h"
+#include "feature/nodelist/networkstatus.h"
+#include "lib/ctime/di_ops.h"
+#include "trunnel/sendme.h"
+
+/* Return the minimum version given by the consensus (if any) that should be
+ * used when emitting a SENDME cell. */
+STATIC int
+get_emit_min_version(void)
+{
+  return networkstatus_get_param(NULL, "sendme_emit_min_version",
+                                 SENDME_EMIT_MIN_VERSION_DEFAULT,
+                                 SENDME_EMIT_MIN_VERSION_MIN,
+                                 SENDME_EMIT_MIN_VERSION_MAX);
+}
+
+/* Return the minimum version given by the consensus (if any) that should be
+ * accepted when receiving a SENDME cell. */
+STATIC int
+get_accept_min_version(void)
+{
+  return networkstatus_get_param(NULL, "sendme_accept_min_version",
+                                 SENDME_ACCEPT_MIN_VERSION_DEFAULT,
+                                 SENDME_ACCEPT_MIN_VERSION_MIN,
+                                 SENDME_ACCEPT_MIN_VERSION_MAX);
+}
+
+/* Pop the first cell digset on the given circuit from the SENDME last digests
+ * list. NULL is returned if the list is uninitialized or empty.
+ *
+ * The caller gets ownership of the returned digest thus is responsible for
+ * freeing the memory. */
+static uint8_t *
+pop_first_cell_digest(const circuit_t *circ)
+{
+  uint8_t *circ_digest;
+
+  tor_assert(circ);
+
+  if (circ->sendme_last_digests == NULL ||
+      smartlist_len(circ->sendme_last_digests) == 0) {
+    return NULL;
+  }
+
+  /* More cell digest than the SENDME window is never suppose to happen. The
+   * cell should have been rejected before reaching this point due to its
+   * package_window down to 0 leading to a circuit close. Scream loudly but
+   * still pop the element so we don't memory leak. */
+  tor_assert_nonfatal(smartlist_len(circ->sendme_last_digests) <=
+                      CIRCWINDOW_START_MAX / CIRCWINDOW_INCREMENT);
+
+  circ_digest = smartlist_get(circ->sendme_last_digests, 0);
+  smartlist_del_keeporder(circ->sendme_last_digests, 0);
+  return circ_digest;
+}
+
+/* Return true iff the given cell digest matches the first digest in the
+ * circuit sendme list. */
+static bool
+v1_digest_matches(const uint8_t *circ_digest, const uint8_t *cell_digest)
+{
+  tor_assert(circ_digest);
+  tor_assert(cell_digest);
+
+  /* Compare the digest with the one in the SENDME. This cell is invalid
+   * without a perfect match. */
+  if (tor_memneq(circ_digest, cell_digest, TRUNNEL_SENDME_V1_DIGEST_LEN)) {
+    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+           "SENDME v1 cell digest do not match.");
+    return false;
+  }
+
+  /* Digests matches! */
+  return true;
+}
+
+/* Return true iff the given decoded SENDME version 1 cell is valid and
+ * matches the expected digest on the circuit.
+ *
+ * Validation is done by comparing the digest in the cell from the previous
+ * cell we saw which tells us that the other side has in fact seen that cell.
+ * See proposal 289 for more details. */
+static bool
+cell_v1_is_valid(const sendme_cell_t *cell, const uint8_t *circ_digest)
+{
+  tor_assert(cell);
+  tor_assert(circ_digest);
+
+  const uint8_t *cell_digest = sendme_cell_getconstarray_data_v1_digest(cell);
+  return v1_digest_matches(circ_digest, cell_digest);
+}
+
+/* Return true iff the given cell version can be handled or if the minimum
+ * accepted version from the consensus is known to us. */
+STATIC bool
+cell_version_can_be_handled(uint8_t cell_version)
+{
+  int accept_version = get_accept_min_version();
+
+  /* We will first check if the consensus minimum accepted version can be
+   * handled by us and if not, regardless of the cell version we got, we can't
+   * continue. */
+  if (accept_version > SENDME_MAX_SUPPORTED_VERSION) {
+    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+           "Unable to accept SENDME version %u (from consensus). "
+           "We only support <= %u. Probably your tor is too old?",
+           accept_version, SENDME_MAX_SUPPORTED_VERSION);
+    goto invalid;
+  }
+
+  /* Then, is this version below the accepted version from the consensus? If
+   * yes, we must not handle it. */
+  if (cell_version < accept_version) {
+    log_info(LD_PROTOCOL, "Unacceptable SENDME version %u. Only "
+                          "accepting %u (from consensus). Closing circuit.",
+             cell_version, accept_version);
+    goto invalid;
+  }
+
+  /* Is this cell version supported by us? */
+  if (cell_version > SENDME_MAX_SUPPORTED_VERSION) {
+    log_info(LD_PROTOCOL, "SENDME cell version %u is not supported by us. "
+                          "We only support <= %u",
+             cell_version, SENDME_MAX_SUPPORTED_VERSION);
+    goto invalid;
+  }
+
+  return true;
+ invalid:
+  return false;
+}
+
+/* Return true iff the encoded SENDME cell in cell_payload of length
+ * cell_payload_len is valid. For each version:
+ *
+ *  0: No validation
+ *  1: Authenticated with last cell digest.
+ *
+ * This is the main critical function to make sure we can continue to
+ * send/recv cells on a circuit. If the SENDME is invalid, the circuit should
+ * be marked for close by the caller. */
+STATIC bool
+sendme_is_valid(const circuit_t *circ, const uint8_t *cell_payload,
+                size_t cell_payload_len)
+{
+  uint8_t cell_version;
+  uint8_t *circ_digest = NULL;
+  sendme_cell_t *cell = NULL;
+
+  tor_assert(circ);
+  tor_assert(cell_payload);
+
+  /* An empty payload means version 0 so skip trunnel parsing. We won't be
+   * able to parse a 0 length buffer into a valid SENDME cell. */
+  if (cell_payload_len == 0) {
+    cell_version = 0;
+  } else {
+    /* First we'll decode the cell so we can get the version. */
+    if (sendme_cell_parse(&cell, cell_payload, cell_payload_len) < 0) {
+      log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+             "Unparseable SENDME cell received. Closing circuit.");
+      goto invalid;
+    }
+    cell_version = sendme_cell_get_version(cell);
+  }
+
+  /* Validate that we can handle this cell version. */
+  if (!cell_version_can_be_handled(cell_version)) {
+    goto invalid;
+  }
+
+  /* Pop the first element that was added (FIFO). We do that regardless of the
+   * version so we don't accumulate on the circuit if v0 is used by the other
+   * end point. */
+  circ_digest = pop_first_cell_digest(circ);
+  if (circ_digest == NULL) {
+    /* We shouldn't have received a SENDME if we have no digests. Log at
+     * protocol warning because it can be tricked by sending many SENDMEs
+     * without prior data cell. */
+    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+           "We received a SENDME but we have no cell digests to match. "
+           "Closing circuit.");
+    goto invalid;
+  }
+
+  /* Validate depending on the version now. */
+  switch (cell_version) {
+  case 0x01:
+    if (!cell_v1_is_valid(cell, circ_digest)) {
+      goto invalid;
+    }
+    break;
+  case 0x00:
+    /* Version 0, there is no work to be done on the payload so it is
+     * necessarily valid if we pass the version validation. */
+    break;
+  default:
+    log_warn(LD_PROTOCOL, "Unknown SENDME cell version %d received.",
+             cell_version);
+    tor_assert_nonfatal_unreached();
+    break;
+  }
+
+  /* Valid cell. */
+  sendme_cell_free(cell);
+  tor_free(circ_digest);
+  return true;
+ invalid:
+  sendme_cell_free(cell);
+  tor_free(circ_digest);
+  return false;
+}
+
+/* Build and encode a version 1 SENDME cell into payload, which must be at
+ * least of RELAY_PAYLOAD_SIZE bytes, using the digest for the cell data.
+ *
+ * Return the size in bytes of the encoded cell in payload. A negative value
+ * is returned on encoding failure. */
+STATIC ssize_t
+build_cell_payload_v1(const uint8_t *cell_digest, uint8_t *payload)
+{
+  ssize_t len = -1;
+  sendme_cell_t *cell = NULL;
+
+  tor_assert(cell_digest);
+  tor_assert(payload);
+
+  cell = sendme_cell_new();
+
+  /* Building a payload for version 1. */
+  sendme_cell_set_version(cell, 0x01);
+  /* Set the data length field for v1. */
+  sendme_cell_set_data_len(cell, TRUNNEL_SENDME_V1_DIGEST_LEN);
+
+  /* Copy the digest into the data payload. */
+  memcpy(sendme_cell_getarray_data_v1_digest(cell), cell_digest,
+         sendme_cell_get_data_len(cell));
+
+  /* Finally, encode the cell into the payload. */
+  len = sendme_cell_encode(payload, RELAY_PAYLOAD_SIZE, cell);
+
+  sendme_cell_free(cell);
+  return len;
+}
+
+/* Send a circuit-level SENDME on the given circuit using the layer_hint if
+ * not NULL. The digest is only used for version 1.
+ *
+ * Return 0 on success else a negative value and the circuit will be closed
+ * because we failed to send the cell on it. */
+static int
+send_circuit_level_sendme(circuit_t *circ, crypt_path_t *layer_hint,
+                          const uint8_t *cell_digest)
+{
+  uint8_t emit_version;
+  uint8_t payload[RELAY_PAYLOAD_SIZE];
+  ssize_t payload_len;
+
+  tor_assert(circ);
+  tor_assert(cell_digest);
+
+  emit_version = get_emit_min_version();
+  switch (emit_version) {
+  case 0x01:
+    payload_len = build_cell_payload_v1(cell_digest, payload);
+    if (BUG(payload_len < 0)) {
+      /* Unable to encode the cell, abort. We can recover from this by closing
+       * the circuit but in theory it should never happen. */
+      return -1;
+    }
+    log_debug(LD_PROTOCOL, "Emitting SENDME version 1 cell.");
+    break;
+  case 0x00:
+    /* Fallthrough because default is to use v0. */
+  default:
+    /* Unknown version, fallback to version 0 meaning no payload. */
+    payload_len = 0;
+    log_debug(LD_PROTOCOL, "Emitting SENDME version 0 cell. "
+                           "Consensus emit version is %d", emit_version);
+    break;
+  }
+
+  if (relay_send_command_from_edge(0, circ, RELAY_COMMAND_SENDME,
+                                   (char *) payload, payload_len,
+                                   layer_hint) < 0) {
+    log_warn(LD_CIRC,
+             "SENDME relay_send_command_from_edge failed. Circuit's closed.");
+    return -1; /* the circuit's closed, don't continue */
+  }
+  return 0;
+}
+
+/* Record the cell digest only if the next cell is expected to be a SENDME. */
+static void
+record_cell_digest_on_circ(circuit_t *circ, const uint8_t *sendme_digest)
+{
+  tor_assert(circ);
+  tor_assert(sendme_digest);
+
+  /* Add the digest to the last seen list in the circuit. */
+  if (circ->sendme_last_digests == NULL) {
+    circ->sendme_last_digests = smartlist_new();
+  }
+  smartlist_add(circ->sendme_last_digests,
+                tor_memdup(sendme_digest, DIGEST_LEN));
+}
+
+/*
+ * Public API
+ */
+
+/** Return true iff the next cell for the given cell window is expected to be
+ * a SENDME.
+ *
+ * We are able to know that because the package or deliver window value minus
+ * one cell (the possible SENDME cell) should be a multiple of the increment
+ * window value. */
+static bool
+circuit_sendme_cell_is_next(int window)
+{
+  /* At the start of the window, no SENDME will be expected. */
+  if (window == CIRCWINDOW_START) {
+    return false;
+  }
+
+  /* Are we at the limit of the increment and if not, we don't expect next
+   * cell is a SENDME.
+   *
+   * We test against the window minus 1 because when we are looking if the
+   * next cell is a SENDME, the window (either package or deliver) hasn't been
+   * decremented just yet so when this is called, we are currently processing
+   * the "window - 1" cell.
+   *
+   * This function is used when recording a cell digest and this is done quite
+   * low in the stack when decrypting or encrypting a cell. The window is only
+   * updated once the cell is actually put in the outbuf. */
+  if (((window - 1) % CIRCWINDOW_INCREMENT) != 0) {
+    return false;
+  }
+
+  /* Next cell is expected to be a SENDME. */
+  return true;
+}
+
+/** Called when we've just received a relay data cell, when we've just
+ * finished flushing all bytes to stream <b>conn</b>, or when we've flushed
+ * *some* bytes to the stream <b>conn</b>.
+ *
+ * If conn->outbuf is not too full, and our deliver window is low, send back a
+ * suitable number of stream-level sendme cells.
+ */
+void
+sendme_connection_edge_consider_sending(edge_connection_t *conn)
+{
+  tor_assert(conn);
+
+  int log_domain = TO_CONN(conn)->type == CONN_TYPE_AP ? LD_APP : LD_EXIT;
+
+  /* Don't send it if we still have data to deliver. */
+  if (connection_outbuf_too_full(TO_CONN(conn))) {
+    goto end;
+  }
+
+  if (circuit_get_by_edge_conn(conn) == NULL) {
+    /* This can legitimately happen if the destroy has already arrived and
+     * torn down the circuit. */
+    log_info(log_domain, "No circuit associated with edge connection. "
+                         "Skipping sending SENDME.");
+    goto end;
+  }
+
+  while (conn->deliver_window <=
+         (STREAMWINDOW_START - STREAMWINDOW_INCREMENT)) {
+    log_debug(log_domain, "Outbuf %" TOR_PRIuSZ ", queuing stream SENDME.",
+              TO_CONN(conn)->outbuf_flushlen);
+    conn->deliver_window += STREAMWINDOW_INCREMENT;
+    if (connection_edge_send_command(conn, RELAY_COMMAND_SENDME,
+                                     NULL, 0) < 0) {
+      log_warn(LD_BUG, "connection_edge_send_command failed while sending "
+                       "a SENDME. Circuit probably closed, skipping.");
+      goto end; /* The circuit's closed, don't continue */
+    }
+  }
+
+ end:
+  return;
+}
+
+/** Check if the deliver_window for circuit <b>circ</b> (at hop
+ * <b>layer_hint</b> if it's defined) is low enough that we should
+ * send a circuit-level sendme back down the circuit. If so, send
+ * enough sendmes that the window would be overfull if we sent any
+ * more.
+ */
+void
+sendme_circuit_consider_sending(circuit_t *circ, crypt_path_t *layer_hint)
+{
+  bool sent_one_sendme = false;
+  const uint8_t *digest;
+
+  while ((layer_hint ? layer_hint->deliver_window : circ->deliver_window) <=
+          CIRCWINDOW_START - CIRCWINDOW_INCREMENT) {
+    log_debug(LD_CIRC,"Queuing circuit sendme.");
+    if (layer_hint) {
+      layer_hint->deliver_window += CIRCWINDOW_INCREMENT;
+      digest = cpath_get_sendme_digest(layer_hint);
+    } else {
+      circ->deliver_window += CIRCWINDOW_INCREMENT;
+      digest = relay_crypto_get_sendme_digest(&TO_OR_CIRCUIT(circ)->crypto);
+    }
+    if (send_circuit_level_sendme(circ, layer_hint, digest) < 0) {
+      return; /* The circuit's closed, don't continue */
+    }
+    /* Current implementation is not suppose to send multiple SENDME at once
+     * because this means we would use the same relay crypto digest for each
+     * SENDME leading to a mismatch on the other side and the circuit to
+     * collapse. Scream loudly if it ever happens so we can address it. */
+    tor_assert_nonfatal(!sent_one_sendme);
+    sent_one_sendme = true;
+  }
+}
+
+/* Process a circuit-level SENDME cell that we just received. The layer_hint,
+ * if not NULL, is the Exit hop of the connection which means that we are a
+ * client. In that case, circ must be an origin circuit. The cell_body_len is
+ * the length of the SENDME cell payload (excluding the header). The
+ * cell_payload is the payload.
+ *
+ * Return 0 on success (the SENDME is valid and the package window has
+ * been updated properly).
+ *
+ * On error, a negative value is returned, which indicates that the
+ * circuit must be closed using the value as the reason for it. */
+int
+sendme_process_circuit_level(crypt_path_t *layer_hint,
+                             circuit_t *circ, const uint8_t *cell_payload,
+                             uint16_t cell_payload_len)
+{
+  tor_assert(circ);
+  tor_assert(cell_payload);
+
+  /* Validate the SENDME cell. Depending on the version, different validation
+   * can be done. An invalid SENDME requires us to close the circuit. */
+  if (!sendme_is_valid(circ, cell_payload, cell_payload_len)) {
+    return -END_CIRC_REASON_TORPROTOCOL;
+  }
+
+  /* If we are the origin of the circuit, we are the Client so we use the
+   * layer hint (the Exit hop) for the package window tracking. */
+  if (CIRCUIT_IS_ORIGIN(circ)) {
+    /* If we are the origin of the circuit, it is impossible to not have a
+     * cpath. Just in case, bug on it and close the circuit. */
+    if (BUG(layer_hint == NULL)) {
+      return -END_CIRC_REASON_TORPROTOCOL;
+    }
+    if ((layer_hint->package_window + CIRCWINDOW_INCREMENT) >
+        CIRCWINDOW_START_MAX) {
+      static struct ratelim_t exit_warn_ratelim = RATELIM_INIT(600);
+      log_fn_ratelim(&exit_warn_ratelim, LOG_WARN, LD_PROTOCOL,
+                     "Unexpected sendme cell from exit relay. "
+                     "Closing circ.");
+      return -END_CIRC_REASON_TORPROTOCOL;
+    }
+    layer_hint->package_window += CIRCWINDOW_INCREMENT;
+    log_debug(LD_APP, "circ-level sendme at origin, packagewindow %d.",
+              layer_hint->package_window);
+
+    /* We count circuit-level sendme's as valid delivered data because they
+     * are rate limited. */
+    circuit_read_valid_data(TO_ORIGIN_CIRCUIT(circ), cell_payload_len);
+  } else {
+    /* We aren't the origin of this circuit so we are the Exit and thus we
+     * track the package window with the circuit object. */
+    if ((circ->package_window + CIRCWINDOW_INCREMENT) >
+        CIRCWINDOW_START_MAX) {
+      static struct ratelim_t client_warn_ratelim = RATELIM_INIT(600);
+      log_fn_ratelim(&client_warn_ratelim, LOG_PROTOCOL_WARN, LD_PROTOCOL,
+                     "Unexpected sendme cell from client. "
+                     "Closing circ (window %d).", circ->package_window);
+      return -END_CIRC_REASON_TORPROTOCOL;
+    }
+    circ->package_window += CIRCWINDOW_INCREMENT;
+    log_debug(LD_EXIT, "circ-level sendme at non-origin, packagewindow %d.",
+              circ->package_window);
+  }
+
+  return 0;
+}
+
+/* Process a stream-level SENDME cell that we just received. The conn is the
+ * edge connection (stream) that the circuit circ is associated with. The
+ * cell_body_len is the length of the payload (excluding the header).
+ *
+ * Return 0 on success (the SENDME is valid and the package window has
+ * been updated properly).
+ *
+ * On error, a negative value is returned, which indicates that the
+ * circuit must be closed using the value as the reason for it. */
+int
+sendme_process_stream_level(edge_connection_t *conn, circuit_t *circ,
+                            uint16_t cell_body_len)
+{
+  tor_assert(conn);
+  tor_assert(circ);
+
+  /* Don't allow the other endpoint to request more than our maximum (i.e.
+   * initial) stream SENDME window worth of data. Well-behaved stock clients
+   * will not request more than this max (as per the check in the while loop
+   * of sendme_connection_edge_consider_sending()). */
+  if ((conn->package_window + STREAMWINDOW_INCREMENT) >
+      STREAMWINDOW_START_MAX) {
+    static struct ratelim_t stream_warn_ratelim = RATELIM_INIT(600);
+    log_fn_ratelim(&stream_warn_ratelim, LOG_PROTOCOL_WARN, LD_PROTOCOL,
+                   "Unexpected stream sendme cell. Closing circ (window %d).",
+                   conn->package_window);
+    return -END_CIRC_REASON_TORPROTOCOL;
+  }
+  /* At this point, the stream sendme is valid */
+  conn->package_window += STREAMWINDOW_INCREMENT;
+
+  /* We count circuit-level sendme's as valid delivered data because they are
+   * rate limited. */
+  if (CIRCUIT_IS_ORIGIN(circ)) {
+    circuit_read_valid_data(TO_ORIGIN_CIRCUIT(circ), cell_body_len);
+  }
+
+  log_debug(CIRCUIT_IS_ORIGIN(circ) ? LD_APP : LD_EXIT,
+            "stream-level sendme, package_window now %d.",
+            conn->package_window);
+  return 0;
+}
+
+/* Called when a relay DATA cell is received on the given circuit. If
+ * layer_hint is NULL, this means we are the Exit end point else we are the
+ * Client. Update the deliver window and return its new value. */
+int
+sendme_circuit_data_received(circuit_t *circ, crypt_path_t *layer_hint)
+{
+  int deliver_window, domain;
+
+  if (CIRCUIT_IS_ORIGIN(circ)) {
+    tor_assert(layer_hint);
+    --layer_hint->deliver_window;
+    deliver_window = layer_hint->deliver_window;
+    domain = LD_APP;
+  } else {
+    tor_assert(!layer_hint);
+    --circ->deliver_window;
+    deliver_window = circ->deliver_window;
+    domain = LD_EXIT;
+  }
+
+  log_debug(domain, "Circuit deliver_window now %d.", deliver_window);
+  return deliver_window;
+}
+
+/* Called when a relay DATA cell is received for the given edge connection
+ * conn. Update the deliver window and return its new value. */
+int
+sendme_stream_data_received(edge_connection_t *conn)
+{
+  tor_assert(conn);
+  return --conn->deliver_window;
+}
+
+/* Called when a relay DATA cell is packaged on the given circuit. If
+ * layer_hint is NULL, this means we are the Exit end point else we are the
+ * Client. Update the package window and return its new value. */
+int
+sendme_note_circuit_data_packaged(circuit_t *circ, crypt_path_t *layer_hint)
+{
+  int package_window, domain;
+
+  tor_assert(circ);
+
+  if (CIRCUIT_IS_ORIGIN(circ)) {
+    /* Client side. */
+    tor_assert(layer_hint);
+    --layer_hint->package_window;
+    package_window = layer_hint->package_window;
+    domain = LD_APP;
+  } else {
+    /* Exit side. */
+    tor_assert(!layer_hint);
+    --circ->package_window;
+    package_window = circ->package_window;
+    domain = LD_EXIT;
+  }
+
+  log_debug(domain, "Circuit package_window now %d.", package_window);
+  return package_window;
+}
+
+/* Called when a relay DATA cell is packaged for the given edge connection
+ * conn. Update the package window and return its new value. */
+int
+sendme_note_stream_data_packaged(edge_connection_t *conn)
+{
+  tor_assert(conn);
+
+  --conn->package_window;
+  log_debug(LD_APP, "Stream package_window now %d.", conn->package_window);
+  return conn->package_window;
+}
+
+/* Record the cell digest into the circuit sendme digest list depending on
+ * which edge we are. The digest is recorded only if we expect the next cell
+ * that we will receive is a SENDME so we can match the digest. */
+void
+sendme_record_cell_digest_on_circ(circuit_t *circ, crypt_path_t *cpath)
+{
+  int package_window;
+  uint8_t *sendme_digest;
+
+  tor_assert(circ);
+
+  package_window = circ->package_window;
+  if (cpath) {
+    package_window = cpath->package_window;
+  }
+
+  /* Is this the last cell before a SENDME? The idea is that if the
+   * package_window reaches a multiple of the increment, after this cell, we
+   * should expect a SENDME. */
+  if (!circuit_sendme_cell_is_next(package_window)) {
+    return;
+  }
+
+  /* Getting the digest is expensive so we only do it once we are certain to
+   * record it on the circuit. */
+  if (cpath) {
+    sendme_digest = cpath_get_sendme_digest(cpath);
+  } else {
+    sendme_digest =
+      relay_crypto_get_sendme_digest(&TO_OR_CIRCUIT(circ)->crypto);
+  }
+
+  record_cell_digest_on_circ(circ, sendme_digest);
+}
+
+/* Called once we decrypted a cell and recognized it. Record the cell digest
+ * as the next sendme digest only if the next cell we'll send on the circuit
+ * is expected to be a SENDME. */
+void
+sendme_record_received_cell_digest(circuit_t *circ, crypt_path_t *cpath)
+{
+  tor_assert(circ);
+
+  /* Only record if the next cell is expected to be a SENDME. */
+  if (!circuit_sendme_cell_is_next(cpath ? cpath->deliver_window :
+                                           circ->deliver_window)) {
+    return;
+  }
+
+  if (cpath) {
+    /* Record incoming digest. */
+    cpath_sendme_record_cell_digest(cpath, false);
+  } else {
+    /* Record foward digest. */
+    relay_crypto_record_sendme_digest(&TO_OR_CIRCUIT(circ)->crypto, true);
+  }
+}
+
+/* Called once we encrypted a cell. Record the cell digest as the next sendme
+ * digest only if the next cell we expect to receive is a SENDME so we can
+ * match the digests. */
+void
+sendme_record_sending_cell_digest(circuit_t *circ, crypt_path_t *cpath)
+{
+  tor_assert(circ);
+
+  /* Only record if the next cell is expected to be a SENDME. */
+  if (!circuit_sendme_cell_is_next(cpath ? cpath->package_window :
+                                           circ->package_window)) {
+    goto end;
+  }
+
+  if (cpath) {
+    /* Record the forward digest. */
+    cpath_sendme_record_cell_digest(cpath, true);
+  } else {
+    /* Record the incoming digest. */
+    relay_crypto_record_sendme_digest(&TO_OR_CIRCUIT(circ)->crypto, false);
+  }
+
+ end:
+  return;
+}
diff --git a/src/core/or/sendme.h b/src/core/or/sendme.h
new file mode 100644
index 000000000..20477103f
--- /dev/null
+++ b/src/core/or/sendme.h
@@ -0,0 +1,80 @@
+/* Copyright (c) 2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file sendme.h
+ * \brief Header file for sendme.c.
+ **/
+
+#ifndef TOR_SENDME_H
+#define TOR_SENDME_H
+
+#include "core/or/edge_connection_st.h"
+#include "core/or/crypt_path_st.h"
+#include "core/or/circuit_st.h"
+
+/* Sending SENDME cell. */
+void sendme_connection_edge_consider_sending(edge_connection_t *edge_conn);
+void sendme_circuit_consider_sending(circuit_t *circ,
+                                     crypt_path_t *layer_hint);
+
+/* Processing SENDME cell. */
+int sendme_process_circuit_level(crypt_path_t *layer_hint,
+                                 circuit_t *circ, const uint8_t *cell_payload,
+                                 uint16_t cell_payload_len);
+int sendme_process_stream_level(edge_connection_t *conn, circuit_t *circ,
+                                uint16_t cell_body_len);
+
+/* Update deliver window functions. */
+int sendme_stream_data_received(edge_connection_t *conn);
+int sendme_circuit_data_received(circuit_t *circ, crypt_path_t *layer_hint);
+
+/* Update package window functions. */
+int sendme_note_circuit_data_packaged(circuit_t *circ,
+                                      crypt_path_t *layer_hint);
+int sendme_note_stream_data_packaged(edge_connection_t *conn);
+
+/* Record cell digest on circuit. */
+void sendme_record_cell_digest_on_circ(circuit_t *circ, crypt_path_t *cpath);
+/* Record cell digest as the SENDME digest. */
+void sendme_record_received_cell_digest(circuit_t *circ, crypt_path_t *cpath);
+void sendme_record_sending_cell_digest(circuit_t *circ, crypt_path_t *cpath);
+
+/* Private section starts. */
+#ifdef SENDME_PRIVATE
+
+/* The maximum supported version. Above that value, the cell can't be
+ * recognized as a valid SENDME. */
+#define SENDME_MAX_SUPPORTED_VERSION 1
+
+/* The cell version constants for when emitting a cell. */
+#define SENDME_EMIT_MIN_VERSION_DEFAULT 0
+#define SENDME_EMIT_MIN_VERSION_MIN 0
+#define SENDME_EMIT_MIN_VERSION_MAX UINT8_MAX
+
+/* The cell version constants for when accepting a cell. */
+#define SENDME_ACCEPT_MIN_VERSION_DEFAULT 0
+#define SENDME_ACCEPT_MIN_VERSION_MIN 0
+#define SENDME_ACCEPT_MIN_VERSION_MAX UINT8_MAX
+
+/*
+ * Unit tests declaractions.
+ */
+#ifdef TOR_UNIT_TESTS
+
+STATIC int get_emit_min_version(void);
+STATIC int get_accept_min_version(void);
+
+STATIC bool cell_version_can_be_handled(uint8_t cell_version);
+
+STATIC ssize_t build_cell_payload_v1(const uint8_t *cell_digest,
+                                     uint8_t *payload);
+STATIC bool sendme_is_valid(const circuit_t *circ,
+                            const uint8_t *cell_payload,
+                            size_t cell_payload_len);
+
+#endif /* defined(TOR_UNIT_TESTS) */
+
+#endif /* defined(SENDME_PRIVATE) */
+
+#endif /* !defined(TOR_SENDME_H) */
diff --git a/src/core/or/server_port_cfg_st.h b/src/core/or/server_port_cfg_st.h
index bd026af7e..0738735c6 100644
--- a/src/core/or/server_port_cfg_st.h
+++ b/src/core/or/server_port_cfg_st.h
@@ -16,5 +16,5 @@ struct server_port_cfg_t {
   unsigned int bind_ipv6_only : 1;
 };
 
-#endif
+#endif /* !defined(SERVER_PORT_CFG_ST_H) */
 
diff --git a/src/core/or/socks_request_st.h b/src/core/or/socks_request_st.h
index 5922870c6..9fb941ff7 100644
--- a/src/core/or/socks_request_st.h
+++ b/src/core/or/socks_request_st.h
@@ -74,4 +74,4 @@ struct socks_request_t {
   uint8_t socks5_atyp; /* SOCKS5 address type */
 };
 
-#endif
+#endif /* !defined(SOCKS_REQUEST_ST_H) */
diff --git a/src/core/or/tor_version_st.h b/src/core/or/tor_version_st.h
index 716429bd3..c5bdcaf07 100644
--- a/src/core/or/tor_version_st.h
+++ b/src/core/or/tor_version_st.h
@@ -28,5 +28,5 @@ struct tor_version_t {
   char git_tag[DIGEST_LEN];
 };
 
-#endif
+#endif /* !defined(TOR_VERSION_ST_H) */
 
diff --git a/src/core/or/var_cell_st.h b/src/core/or/var_cell_st.h
index 4287c83f6..607c0d6c8 100644
--- a/src/core/or/var_cell_st.h
+++ b/src/core/or/var_cell_st.h
@@ -19,5 +19,5 @@ struct var_cell_t {
   uint8_t payload[FLEXIBLE_ARRAY_MEMBER];
 };
 
-#endif
+#endif /* !defined(VAR_CELL_ST_H) */
 
diff --git a/src/core/or/versions.c b/src/core/or/versions.c
index 2a572d470..06417bb4e 100644
--- a/src/core/or/versions.c
+++ b/src/core/or/versions.c
@@ -448,8 +448,9 @@ memoize_protover_summary(protover_summary_flags_t *out,
   out->supports_v3_rendezvous_point =
     protocol_list_supports_protocol(protocols, PRT_HSREND,
                                     PROTOVER_HS_RENDEZVOUS_POINT_V3);
-    out->supports_padding =
-      protocol_list_supports_protocol(protocols, PRT_PADDING, 1);
+  out->supports_hs_setup_padding =
+    protocol_list_supports_protocol(protocols, PRT_PADDING,
+              PROTOVER_HS_SETUP_PADDING);
 
   protover_summary_flags_t *new_cached = tor_memdup(out, sizeof(*out));
   cached = strmap_set(protover_summary_map, protocols, new_cached);
diff --git a/src/core/proto/proto_socks.c b/src/core/proto/proto_socks.c
index ac0c9e911..b657a7b75 100644
--- a/src/core/proto/proto_socks.c
+++ b/src/core/proto/proto_socks.c
@@ -8,7 +8,7 @@
 #include "feature/client/addressmap.h"
 #include "lib/buf/buffers.h"
 #include "core/mainloop/connection.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "app/config/config.h"
 #include "lib/crypt_ops/crypto_util.h"
 #include "feature/relay/ext_orport.h"
diff --git a/src/ext/include.am b/src/ext/include.am
index 6bdce2d79..317e25d78 100644
--- a/src/ext/include.am
+++ b/src/ext/include.am
@@ -143,6 +143,7 @@ noinst_HEADERS += $(ED25519_DONNA_HDRS)
 LIBED25519_DONNA=src/ext/ed25519/donna/libed25519_donna.a
 noinst_LIBRARIES += $(LIBED25519_DONNA)
 
+if BUILD_KECCAK_TINY
 src_ext_keccak_tiny_libkeccak_tiny_a_CFLAGS=\
   @CFLAGS_CONSTTIME@
 
@@ -156,6 +157,7 @@ noinst_HEADERS += $(LIBKECCAK_TINY_HDRS)
 
 LIBKECCAK_TINY=src/ext/keccak-tiny/libkeccak-tiny.a
 noinst_LIBRARIES += $(LIBKECCAK_TINY)
+endif
 
 EXTRA_DIST += \
 	src/ext/timeouts/bench/bench-add.lua 		\
diff --git a/src/ext/timeouts/.may_include b/src/ext/timeouts/.may_include
index 42f44befd..92c711655 100644
--- a/src/ext/timeouts/.may_include
+++ b/src/ext/timeouts/.may_include
@@ -1,6 +1,5 @@
 orconfig.h
 
 ext/tor_queue.h
-timeout-bitops.c
-timeout-debug.h
-timeout.h
+ext/timeouts/*.h
+ext/timeouts/timeout-bitops.c
diff --git a/src/ext/timeouts/test-timeout.c b/src/ext/timeouts/test-timeout.c
index 807712937..52d2e31e0 100644
--- a/src/ext/timeouts/test-timeout.c
+++ b/src/ext/timeouts/test-timeout.c
@@ -4,7 +4,7 @@
 #include <assert.h>
 #include <limits.h>
 
-#include "timeout.h"
+#include "ext/timeouts/timeout.h"
 
 #define THE_END_OF_TIME ((timeout_t)-1)
 
diff --git a/src/ext/timeouts/timeout.c b/src/ext/timeouts/timeout.c
index 07d06772c..79fcc168e 100644
--- a/src/ext/timeouts/timeout.c
+++ b/src/ext/timeouts/timeout.c
@@ -40,14 +40,14 @@
 
 #include "ext/tor_queue.h" /* TAILQ(3) */
 
-#include "timeout.h"
+#include "ext/timeouts/timeout.h"
 
 #ifndef TIMEOUT_DEBUG
 #define TIMEOUT_DEBUG 0
 #endif
 
 #if TIMEOUT_DEBUG - 0
-#include "timeout-debug.h"
+#include "ext/timeouts/timeout-debug.h"
 #endif
 
 #ifdef TIMEOUT_DISABLE_RELATIVE_ACCESS
@@ -141,7 +141,7 @@
 #define WHEEL_MASK (WHEEL_LEN - 1)
 #define TIMEOUT_MAX ((TIMEOUT_C(1) << (WHEEL_BIT * WHEEL_NUM)) - 1)
 
-#include "timeout-bitops.c"
+#include "ext/timeouts/timeout-bitops.c"
 
 #if WHEEL_BIT == 6
 #define ctz(n) ctz64(n)
diff --git a/src/ext/tinytest.c b/src/ext/tinytest.c
index 16f11e463..239fdd0a3 100644
--- a/src/ext/tinytest.c
+++ b/src/ext/tinytest.c
@@ -492,6 +492,12 @@ tinytest_set_test_skipped_(void)
 		cur_test_outcome = SKIP;
 }
 
+int
+tinytest_cur_test_has_failed(void)
+{
+	return (cur_test_outcome == FAIL);
+}
+
 char *
 tinytest_format_hex_(const void *val_, unsigned long len)
 {
diff --git a/src/ext/tinytest.h b/src/ext/tinytest.h
index ed07b26bc..05c2fda05 100644
--- a/src/ext/tinytest.h
+++ b/src/ext/tinytest.h
@@ -72,6 +72,9 @@ struct testlist_alias_t {
 };
 #define END_OF_ALIASES { NULL, NULL }
 
+/** Return true iff the current test has failed. */
+int tinytest_cur_test_has_failed(void);
+
 /** Implementation: called from a test to indicate failure, before logging. */
 void tinytest_set_test_failed_(void);
 /** Implementation: called from a test to indicate that we're skipping. */
diff --git a/src/feature/api/tor_api.c b/src/feature/api/tor_api.c
index 697397d46..fd9d24135 100644
--- a/src/feature/api/tor_api.c
+++ b/src/feature/api/tor_api.c
@@ -40,10 +40,10 @@
 #define raw_socketpair tor_ersatz_socketpair
 #define raw_closesocket closesocket
 #define snprintf _snprintf
-#else
+#else /* !(defined(_WIN32)) */
 #define raw_socketpair socketpair
 #define raw_closesocket close
-#endif
+#endif /* defined(_WIN32) */
 
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
diff --git a/src/feature/api/tor_api.h b/src/feature/api/tor_api.h
index 2bf130c37..cb84853a5 100644
--- a/src/feature/api/tor_api.h
+++ b/src/feature/api/tor_api.h
@@ -55,7 +55,7 @@ typedef SOCKET tor_control_socket_t;
 #else
 typedef int tor_control_socket_t;
 #define INVALID_TOR_CONTROL_SOCKET (-1)
-#endif
+#endif /* defined(_WIN32) */
 
 /** DOCDOC */
 tor_control_socket_t tor_main_configuration_setup_control_socket(
diff --git a/src/feature/client/addressmap.c b/src/feature/client/addressmap.c
index bbe786a6a..c5a27ce8c 100644
--- a/src/feature/client/addressmap.c
+++ b/src/feature/client/addressmap.c
@@ -22,7 +22,7 @@
 #include "core/or/circuituse.h"
 #include "app/config/config.h"
 #include "core/or/connection_edge.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/relay/dns.h"
 #include "feature/nodelist/nodelist.h"
 #include "feature/nodelist/routerset.h"
diff --git a/src/feature/client/bridges.c b/src/feature/client/bridges.c
index 05f89ad36..f51787660 100644
--- a/src/feature/client/bridges.c
+++ b/src/feature/client/bridges.c
@@ -348,7 +348,7 @@ int
 node_is_a_configured_bridge(const node_t *node)
 {
   /* First, let's try searching for a bridge with matching identity. */
-  if (BUG(tor_digest_is_zero(node->identity)))
+  if (BUG(fast_mem_is_zero(node->identity, DIGEST_LEN)))
     return 0;
 
   if (find_bridge_by_digest(node->identity) != NULL)
diff --git a/src/feature/client/circpathbias.c b/src/feature/client/circpathbias.c
index 1743ab5a8..3544dbb85 100644
--- a/src/feature/client/circpathbias.c
+++ b/src/feature/client/circpathbias.c
@@ -176,6 +176,7 @@ pathbias_get_scale_threshold(const or_options_t *options)
 static double
 pathbias_get_scale_ratio(const or_options_t *options)
 {
+  (void) options;
   /*
    * The scale factor is the denominator for our scaling
    * of circuit counts for our path bias window.
@@ -185,7 +186,8 @@ pathbias_get_scale_ratio(const or_options_t *options)
    */
   int denominator = networkstatus_get_param(NULL, "pb_scalefactor",
                               2, 2, INT32_MAX);
-  (void) options;
+  tor_assert(denominator > 0);
+
   /**
    * The mult factor is the numerator for our scaling
    * of circuit counts for our path bias window. It
@@ -369,8 +371,9 @@ pathbias_should_count(origin_circuit_t *circ)
         !circ->build_state->onehop_tunnel) {
       if ((rate_msg = rate_limit_log(&count_limit, approx_time()))) {
         log_info(LD_BUG,
-               "One-hop circuit has length %d. Path state is %s. "
+               "One-hop circuit %d has length %d. Path state is %s. "
                "Circuit is a %s currently %s.%s",
+               circ->global_identifier,
                circ->build_state->desired_path_len,
                pathbias_state_to_string(circ->path_state),
                circuit_purpose_to_string(circ->base_.purpose),
@@ -398,12 +401,13 @@ pathbias_should_count(origin_circuit_t *circ)
   /* Check to see if the shouldcount result has changed due to a
    * unexpected purpose change that would affect our results */
   if (circ->pathbias_shouldcount == PATHBIAS_SHOULDCOUNT_IGNORED) {
-      log_info(LD_BUG,
-              "Circuit %d is now being counted despite being ignored "
-              "in the past. Purpose is %s, path state is %s",
-              circ->global_identifier,
-              circuit_purpose_to_string(circ->base_.purpose),
-              pathbias_state_to_string(circ->path_state));
+    log_info(LD_CIRC,
+            "Circuit %d is not being counted by pathbias because it was "
+            "ignored in the past. Purpose is %s, path state is %s",
+            circ->global_identifier,
+            circuit_purpose_to_string(circ->base_.purpose),
+            pathbias_state_to_string(circ->path_state));
+    return 0;
   }
   circ->pathbias_shouldcount = PATHBIAS_SHOULDCOUNT_COUNTED;
 
@@ -434,8 +438,9 @@ pathbias_count_build_attempt(origin_circuit_t *circ)
       if ((rate_msg = rate_limit_log(&circ_attempt_notice_limit,
                                      approx_time()))) {
         log_info(LD_BUG,
-                "Opened circuit is in strange path state %s. "
+                "Opened circuit %d is in strange path state %s. "
                 "Circuit is a %s currently %s.%s",
+                circ->global_identifier,
                 pathbias_state_to_string(circ->path_state),
                 circuit_purpose_to_string(circ->base_.purpose),
                 circuit_state_to_string(circ->base_.state),
@@ -468,8 +473,9 @@ pathbias_count_build_attempt(origin_circuit_t *circ)
           if ((rate_msg = rate_limit_log(&circ_attempt_notice_limit,
                   approx_time()))) {
             log_info(LD_BUG,
-                   "Unopened circuit has strange path state %s. "
+                   "Unopened circuit %d has strange path state %s. "
                    "Circuit is a %s currently %s.%s",
+                   circ->global_identifier,
                    pathbias_state_to_string(circ->path_state),
                    circuit_purpose_to_string(circ->base_.purpose),
                    circuit_state_to_string(circ->base_.state),
@@ -538,8 +544,9 @@ pathbias_count_build_success(origin_circuit_t *circ)
         if ((rate_msg = rate_limit_log(&success_notice_limit,
                 approx_time()))) {
           log_info(LD_BUG,
-              "Succeeded circuit is in strange path state %s. "
+              "Succeeded circuit %d is in strange path state %s. "
               "Circuit is a %s currently %s.%s",
+              circ->global_identifier,
               pathbias_state_to_string(circ->path_state),
               circuit_purpose_to_string(circ->base_.purpose),
               circuit_state_to_string(circ->base_.state),
@@ -574,8 +581,9 @@ pathbias_count_build_success(origin_circuit_t *circ)
       if ((rate_msg = rate_limit_log(&success_notice_limit,
               approx_time()))) {
         log_info(LD_BUG,
-            "Opened circuit is in strange path state %s. "
+            "Opened circuit %d is in strange path state %s. "
             "Circuit is a %s currently %s.%s",
+            circ->global_identifier,
             pathbias_state_to_string(circ->path_state),
             circuit_purpose_to_string(circ->base_.purpose),
             circuit_state_to_string(circ->base_.state),
@@ -601,8 +609,9 @@ pathbias_count_use_attempt(origin_circuit_t *circ)
 
   if (circ->path_state < PATH_STATE_BUILD_SUCCEEDED) {
     log_notice(LD_BUG,
-        "Used circuit is in strange path state %s. "
+        "Used circuit %d is in strange path state %s. "
         "Circuit is a %s currently %s.",
+        circ->global_identifier,
         pathbias_state_to_string(circ->path_state),
         circuit_purpose_to_string(circ->base_.purpose),
         circuit_state_to_string(circ->base_.state));
diff --git a/src/feature/client/dnsserv.c b/src/feature/client/dnsserv.c
index 44e0caaaf..7fb3fff6c 100644
--- a/src/feature/client/dnsserv.c
+++ b/src/feature/client/dnsserv.c
@@ -26,7 +26,7 @@
 #include "app/config/config.h"
 #include "core/mainloop/connection.h"
 #include "core/or/connection_edge.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "core/mainloop/mainloop.h"
 #include "core/mainloop/netstatus.h"
 #include "core/or/policies.h"
diff --git a/src/feature/client/entrynodes.c b/src/feature/client/entrynodes.c
index e543289ce..54a9238d8 100644
--- a/src/feature/client/entrynodes.c
+++ b/src/feature/client/entrynodes.c
@@ -128,7 +128,7 @@
 #include "feature/client/circpathbias.h"
 #include "feature/client/entrynodes.h"
 #include "feature/client/transports.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dircommon/directory.h"
 #include "feature/nodelist/describe.h"
 #include "feature/nodelist/microdesc.h"
@@ -2611,6 +2611,10 @@ entry_guards_upgrade_waiting_circuits(guard_selection_t *gs,
     entry_guard_t *guard = entry_guard_handle_get(state->guard);
     if (!guard || guard->in_selection != gs)
       continue;
+    if (TO_CIRCUIT(circ)->marked_for_close) {
+      /* Don't consider any marked for close circuits. */
+      continue;
+    }
 
     smartlist_add(all_circuits, circ);
   } SMARTLIST_FOREACH_END(circ);
@@ -3300,6 +3304,9 @@ num_bridges_usable,(int use_maybe_reachable))
   }
 
   SMARTLIST_FOREACH_BEGIN(gs->sampled_entry_guards, entry_guard_t *, guard) {
+    /* Not a bridge, or not one we are configured to be able to use. */
+    if (! guard->is_filtered_guard)
+      continue;
     /* Definitely not usable */
     if (guard->is_reachable == GUARD_REACHABLE_NO)
       continue;
diff --git a/src/feature/client/transports.c b/src/feature/client/transports.c
index e7ff3bf34..97bfc8ae3 100644
--- a/src/feature/client/transports.c
+++ b/src/feature/client/transports.c
@@ -100,7 +100,7 @@
 #include "app/config/statefile.h"
 #include "core/or/connection_or.h"
 #include "feature/relay/ext_orport.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "lib/encoding/confline.h"
 #include "lib/encoding/kvline.h"
 
@@ -1424,11 +1424,6 @@ create_managed_proxy_environment(const managed_proxy_t *mp)
     } else {
       smartlist_add_asprintf(envs, "TOR_PT_EXTENDED_SERVER_PORT=");
     }
-
-    /* All new versions of tor will keep stdin open, so PTs can use it
-     * as a reliable termination detection mechanism.
-     */
-    smartlist_add_asprintf(envs, "TOR_PT_EXIT_ON_STDIN_CLOSE=1");
   } else {
     /* If ClientTransportPlugin has a HTTPS/SOCKS proxy configured, set the
      * TOR_PT_PROXY line.
@@ -1439,6 +1434,11 @@ create_managed_proxy_environment(const managed_proxy_t *mp)
     }
   }
 
+  /* All new versions of tor will keep stdin open, so PTs can use it
+   * as a reliable termination detection mechanism.
+   */
+  smartlist_add_asprintf(envs, "TOR_PT_EXIT_ON_STDIN_CLOSE=1");
+
   SMARTLIST_FOREACH_BEGIN(envs, const char *, env_var) {
     set_environment_variable_in_smartlist(merged_env_vars, env_var,
                                           tor_free_, 1);
diff --git a/src/feature/control/btrack_circuit.h b/src/feature/control/btrack_circuit.h
index c40822f1f..9e06fefb0 100644
--- a/src/feature/control/btrack_circuit.h
+++ b/src/feature/control/btrack_circuit.h
@@ -12,4 +12,4 @@
 int btrack_circ_init(void);
 void btrack_circ_fini(void);
 
-#endif  /* defined(TOR_BTRACK_CIRCUIT_H) */
+#endif /* !defined(TOR_BTRACK_CIRCUIT_H) */
diff --git a/src/feature/control/btrack_orconn.h b/src/feature/control/btrack_orconn.h
index 6ab4892a7..f8f5c1096 100644
--- a/src/feature/control/btrack_orconn.h
+++ b/src/feature/control/btrack_orconn.h
@@ -30,9 +30,9 @@ typedef struct bt_orconn_t {
   bool is_onehop;           /**< Is this for a one-hop circuit? */
 } bt_orconn_t;
 
-#endif  /* defined(BTRACK_ORCONN_PRIVATE) */
+#endif /* defined(BTRACK_ORCONN_PRIVATE) */
 
 int btrack_orconn_init(void);
 void btrack_orconn_fini(void);
 
-#endif  /* defined(TOR_BTRACK_ORCONN_H) */
+#endif /* !defined(TOR_BTRACK_ORCONN_H) */
diff --git a/src/feature/control/btrack_orconn_cevent.c b/src/feature/control/btrack_orconn_cevent.c
index ee142f287..535aa8f61 100644
--- a/src/feature/control/btrack_orconn_cevent.c
+++ b/src/feature/control/btrack_orconn_cevent.c
@@ -20,7 +20,7 @@
 #include "core/or/orconn_event.h"
 #include "feature/control/btrack_orconn.h"
 #include "feature/control/btrack_orconn_cevent.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 
 /**
  * Have we completed our first OR connection?
diff --git a/src/feature/control/btrack_orconn_cevent.h b/src/feature/control/btrack_orconn_cevent.h
index f9d24633a..afec55581 100644
--- a/src/feature/control/btrack_orconn_cevent.h
+++ b/src/feature/control/btrack_orconn_cevent.h
@@ -7,6 +7,7 @@
  **/
 
 #ifndef TOR_BTRACK_ORCONN_CEVENT_H
+#define TOR_BTRACK_ORCONN_CEVENT_H
 
 #include "feature/control/btrack_orconn.h"
 
@@ -14,4 +15,4 @@ void bto_cevent_anyconn(const bt_orconn_t *);
 void bto_cevent_apconn(const bt_orconn_t *);
 void bto_cevent_reset(void);
 
-#endif  /* defined(TOR_BTRACK_ORCONN_CEVENT_H) */
+#endif /* !defined(TOR_BTRACK_ORCONN_CEVENT_H) */
diff --git a/src/feature/control/btrack_orconn_maps.h b/src/feature/control/btrack_orconn_maps.h
index 3ead40984..c2043fa15 100644
--- a/src/feature/control/btrack_orconn_maps.h
+++ b/src/feature/control/btrack_orconn_maps.h
@@ -7,6 +7,7 @@
  **/
 
 #ifndef TOR_BTRACK_ORCONN_MAPS_H
+#define TOR_BTRACK_ORCONN_MAPS_H
 
 void bto_delete(uint64_t);
 bt_orconn_t *bto_find_or_new(uint64_t, uint64_t);
@@ -14,4 +15,4 @@ bt_orconn_t *bto_find_or_new(uint64_t, uint64_t);
 void bto_init_maps(void);
 void bto_clear_maps(void);
 
-#endif  /* defined(TOR_BTRACK_ORCONN_MAPS_H) */
+#endif /* !defined(TOR_BTRACK_ORCONN_MAPS_H) */
diff --git a/src/feature/control/btrack_sys.h b/src/feature/control/btrack_sys.h
index fad35b41d..3f831d064 100644
--- a/src/feature/control/btrack_sys.h
+++ b/src/feature/control/btrack_sys.h
@@ -11,4 +11,4 @@
 
 extern const struct subsys_fns_t sys_btrack;
 
-#endif  /* defined(TOR_BTRACK_SYS_H) */
+#endif /* !defined(TOR_BTRACK_SYS_H) */
diff --git a/src/feature/control/control.c b/src/feature/control/control.c
index 6f8cd8f0a..436bf423c 100644
--- a/src/feature/control/control.c
+++ b/src/feature/control/control.c
@@ -1,4 +1,3 @@
-
 /* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
  * Copyright (c) 2007-2019, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
@@ -33,86 +32,27 @@
  * stack.
  **/
 
+#define CONTROL_MODULE_PRIVATE
 #define CONTROL_PRIVATE
-#define OCIRC_EVENT_PRIVATE
 
 #include "core/or/or.h"
 #include "app/config/config.h"
-#include "app/config/confparse.h"
 #include "app/main/main.h"
 #include "core/mainloop/connection.h"
 #include "core/mainloop/mainloop.h"
-#include "core/or/channel.h"
-#include "core/or/channeltls.h"
-#include "core/or/circuitbuild.h"
-#include "core/or/circuitlist.h"
-#include "core/or/circuitstats.h"
-#include "core/or/circuituse.h"
-#include "core/or/command.h"
-#include "core/or/connection_edge.h"
 #include "core/or/connection_or.h"
-#include "core/or/ocirc_event.h"
-#include "core/or/policies.h"
-#include "core/or/reasons.h"
-#include "core/or/versions.h"
 #include "core/proto/proto_control0.h"
 #include "core/proto/proto_http.h"
-#include "feature/client/addressmap.h"
-#include "feature/client/bridges.h"
-#include "feature/client/dnsserv.h"
-#include "feature/client/entrynodes.h"
 #include "feature/control/control.h"
-#include "feature/control/fmt_serverstatus.h"
-#include "feature/control/getinfo_geoip.h"
-#include "feature/dircache/dirserv.h"
-#include "feature/dirclient/dirclient.h"
-#include "feature/dirclient/dlstatus.h"
-#include "feature/dircommon/directory.h"
-#include "feature/hibernate/hibernate.h"
-#include "feature/hs/hs_cache.h"
-#include "feature/hs/hs_common.h"
-#include "feature/hs/hs_control.h"
-#include "feature/hs_common/shared_random_client.h"
-#include "feature/nodelist/authcert.h"
-#include "feature/nodelist/dirlist.h"
-#include "feature/nodelist/microdesc.h"
-#include "feature/nodelist/networkstatus.h"
-#include "feature/nodelist/nodelist.h"
-#include "feature/nodelist/routerinfo.h"
-#include "feature/nodelist/routerlist.h"
-#include "feature/relay/router.h"
-#include "feature/relay/routermode.h"
-#include "feature/relay/selftest.h"
-#include "feature/rend/rendclient.h"
+#include "feature/control/control_auth.h"
+#include "feature/control/control_cmd.h"
+#include "feature/control/control_events.h"
+#include "feature/control/control_proto.h"
 #include "feature/rend/rendcommon.h"
-#include "feature/rend/rendparse.h"
 #include "feature/rend/rendservice.h"
-#include "feature/stats/geoip_stats.h"
-#include "feature/stats/predict_ports.h"
-#include "lib/buf/buffers.h"
-#include "lib/crypt_ops/crypto_rand.h"
-#include "lib/crypt_ops/crypto_util.h"
-#include "lib/encoding/confline.h"
-#include "lib/evloop/compat_libevent.h"
-#include "lib/version/torversion.h"
+#include "lib/evloop/procmon.h"
 
-#include "feature/dircache/cached_dir_st.h"
 #include "feature/control/control_connection_st.h"
-#include "core/or/cpath_build_state_st.h"
-#include "core/or/entry_connection_st.h"
-#include "feature/nodelist/extrainfo_st.h"
-#include "feature/nodelist/networkstatus_st.h"
-#include "feature/nodelist/node_st.h"
-#include "core/or/or_connection_st.h"
-#include "core/or/or_circuit_st.h"
-#include "core/or/origin_circuit_st.h"
-#include "feature/nodelist/microdesc_st.h"
-#include "feature/rend/rend_authorized_client_st.h"
-#include "feature/rend/rend_encoded_v2_service_descriptor_st.h"
-#include "feature/rend/rend_service_descriptor_st.h"
-#include "feature/nodelist/routerinfo_st.h"
-#include "feature/nodelist/routerlist_st.h"
-#include "core/or/socks_request_st.h"
 
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
@@ -121,145 +61,6 @@
 #include <sys/stat.h>
 #endif
 
-#ifndef _WIN32
-#include <pwd.h>
-#include <sys/resource.h>
-#endif
-
-#include "lib/crypt_ops/crypto_s2k.h"
-#include "lib/evloop/procmon.h"
-#include "lib/evloop/compat_libevent.h"
-
-/** Yield true iff <b>s</b> is the state of a control_connection_t that has
- * finished authentication and is accepting commands. */
-#define STATE_IS_OPEN(s) ((s) == CONTROL_CONN_STATE_OPEN)
-
-/** Bitfield: The bit 1<<e is set if <b>any</b> open control
- * connection is interested in events of type <b>e</b>.  We use this
- * so that we can decide to skip generating event messages that nobody
- * has interest in without having to walk over the global connection
- * list to find out.
- **/
-typedef uint64_t event_mask_t;
-
-/** An event mask of all the events that any controller is interested in
- * receiving. */
-static event_mask_t global_event_mask = 0;
-
-/** True iff we have disabled log messages from being sent to the controller */
-static int disable_log_messages = 0;
-
-/** Macro: true if any control connection is interested in events of type
- * <b>e</b>. */
-#define EVENT_IS_INTERESTING(e) \
-  (!! (global_event_mask & EVENT_MASK_(e)))
-
-/** Macro: true if any event from the bitfield 'e' is interesting. */
-#define ANY_EVENT_IS_INTERESTING(e) \
-  (!! (global_event_mask & (e)))
-
-/** If we're using cookie-type authentication, how long should our cookies be?
- */
-#define AUTHENTICATION_COOKIE_LEN 32
-
-/** If true, we've set authentication_cookie to a secret code and
- * stored it to disk. */
-static int authentication_cookie_is_set = 0;
-/** If authentication_cookie_is_set, a secret cookie that we've stored to disk
- * and which we're using to authenticate controllers.  (If the controller can
- * read it off disk, it has permission to connect.) */
-static uint8_t *authentication_cookie = NULL;
-
-#define SAFECOOKIE_SERVER_TO_CONTROLLER_CONSTANT \
-  "Tor safe cookie authentication server-to-controller hash"
-#define SAFECOOKIE_CONTROLLER_TO_SERVER_CONSTANT \
-  "Tor safe cookie authentication controller-to-server hash"
-#define SAFECOOKIE_SERVER_NONCE_LEN DIGEST256_LEN
-
-/** The list of onion services that have been added via ADD_ONION that do not
- * belong to any particular control connection.
- */
-static smartlist_t *detached_onion_services = NULL;
-
-static void connection_printf_to_buf(control_connection_t *conn,
-                                     const char *format, ...)
-  CHECK_PRINTF(2,3);
-static void send_control_event_impl(uint16_t event,
-                                    const char *format, va_list ap)
-  CHECK_PRINTF(2,0);
-static int control_event_status(int type, int severity, const char *format,
-                                va_list args)
-  CHECK_PRINTF(3,0);
-
-static void send_control_done(control_connection_t *conn);
-static void send_control_event(uint16_t event,
-                               const char *format, ...)
-  CHECK_PRINTF(2,3);
-static int handle_control_setconf(control_connection_t *conn, uint32_t len,
-                                  char *body);
-static int handle_control_resetconf(control_connection_t *conn, uint32_t len,
-                                    char *body);
-static int handle_control_getconf(control_connection_t *conn, uint32_t len,
-                                  const char *body);
-static int handle_control_loadconf(control_connection_t *conn, uint32_t len,
-                                  const char *body);
-static int handle_control_setevents(control_connection_t *conn, uint32_t len,
-                                    const char *body);
-static int handle_control_authenticate(control_connection_t *conn,
-                                       uint32_t len,
-                                       const char *body);
-static int handle_control_signal(control_connection_t *conn, uint32_t len,
-                                 const char *body);
-static int handle_control_mapaddress(control_connection_t *conn, uint32_t len,
-                                     const char *body);
-static char *list_getinfo_options(void);
-static int handle_control_getinfo(control_connection_t *conn, uint32_t len,
-                                  const char *body);
-static int handle_control_extendcircuit(control_connection_t *conn,
-                                        uint32_t len,
-                                        const char *body);
-static int handle_control_setcircuitpurpose(control_connection_t *conn,
-                                            uint32_t len, const char *body);
-static int handle_control_attachstream(control_connection_t *conn,
-                                       uint32_t len,
-                                        const char *body);
-static int handle_control_postdescriptor(control_connection_t *conn,
-                                         uint32_t len,
-                                         const char *body);
-static int handle_control_redirectstream(control_connection_t *conn,
-                                         uint32_t len,
-                                         const char *body);
-static int handle_control_closestream(control_connection_t *conn, uint32_t len,
-                                      const char *body);
-static int handle_control_closecircuit(control_connection_t *conn,
-                                       uint32_t len,
-                                       const char *body);
-static int handle_control_resolve(control_connection_t *conn, uint32_t len,
-                                  const char *body);
-static int handle_control_usefeature(control_connection_t *conn,
-                                     uint32_t len,
-                                     const char *body);
-static int handle_control_hsfetch(control_connection_t *conn, uint32_t len,
-                                  const char *body);
-static int handle_control_hspost(control_connection_t *conn, uint32_t len,
-                                 const char *body);
-static int handle_control_add_onion(control_connection_t *conn, uint32_t len,
-                                    const char *body);
-static int handle_control_del_onion(control_connection_t *conn, uint32_t len,
-                                    const char *body);
-static int write_stream_target_to_buf(entry_connection_t *conn, char *buf,
-                                      size_t len);
-static void orconn_target_get_name(char *buf, size_t len,
-                                   or_connection_t *conn);
-
-static int get_cached_network_liveness(void);
-static void set_cached_network_liveness(int liveness);
-
-static void flush_queued_events_cb(mainloop_event_t *event, void *arg);
-
-static char * download_status_to_string(const download_status_t *dl);
-static void control_get_bytes_rw_last_sec(uint64_t *r, uint64_t *w);
-
 /** Convert a connection_t* to an control_connection_t*; assert if the cast is
  * invalid. */
 control_connection_t *
@@ -269,410 +70,6 @@ TO_CONTROL_CONN(connection_t *c)
   return DOWNCAST(control_connection_t, c);
 }
 
-/** Given a control event code for a message event, return the corresponding
- * log severity. */
-static inline int
-event_to_log_severity(int event)
-{
-  switch (event) {
-    case EVENT_DEBUG_MSG: return LOG_DEBUG;
-    case EVENT_INFO_MSG: return LOG_INFO;
-    case EVENT_NOTICE_MSG: return LOG_NOTICE;
-    case EVENT_WARN_MSG: return LOG_WARN;
-    case EVENT_ERR_MSG: return LOG_ERR;
-    default: return -1;
-  }
-}
-
-/** Given a log severity, return the corresponding control event code. */
-static inline int
-log_severity_to_event(int severity)
-{
-  switch (severity) {
-    case LOG_DEBUG: return EVENT_DEBUG_MSG;
-    case LOG_INFO: return EVENT_INFO_MSG;
-    case LOG_NOTICE: return EVENT_NOTICE_MSG;
-    case LOG_WARN: return EVENT_WARN_MSG;
-    case LOG_ERR: return EVENT_ERR_MSG;
-    default: return -1;
-  }
-}
-
-/** Helper: clear bandwidth counters of all origin circuits. */
-static void
-clear_circ_bw_fields(void)
-{
-  origin_circuit_t *ocirc;
-  SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
-    if (!CIRCUIT_IS_ORIGIN(circ))
-      continue;
-    ocirc = TO_ORIGIN_CIRCUIT(circ);
-    ocirc->n_written_circ_bw = ocirc->n_read_circ_bw = 0;
-    ocirc->n_overhead_written_circ_bw = ocirc->n_overhead_read_circ_bw = 0;
-    ocirc->n_delivered_written_circ_bw = ocirc->n_delivered_read_circ_bw = 0;
-  }
-  SMARTLIST_FOREACH_END(circ);
-}
-
-/** Set <b>global_event_mask*</b> to the bitwise OR of each live control
- * connection's event_mask field. */
-void
-control_update_global_event_mask(void)
-{
-  smartlist_t *conns = get_connection_array();
-  event_mask_t old_mask, new_mask;
-  old_mask = global_event_mask;
-  int any_old_per_sec_events = control_any_per_second_event_enabled();
-
-  global_event_mask = 0;
-  SMARTLIST_FOREACH(conns, connection_t *, _conn,
-  {
-    if (_conn->type == CONN_TYPE_CONTROL &&
-        STATE_IS_OPEN(_conn->state)) {
-      control_connection_t *conn = TO_CONTROL_CONN(_conn);
-      global_event_mask |= conn->event_mask;
-    }
-  });
-
-  new_mask = global_event_mask;
-
-  /* Handle the aftermath.  Set up the log callback to tell us only what
-   * we want to hear...*/
-  control_adjust_event_log_severity();
-
-  /* Macro: true if ev was false before and is true now. */
-#define NEWLY_ENABLED(ev) \
-  (! (old_mask & (ev)) && (new_mask & (ev)))
-
-  /* ...then, if we've started logging stream or circ bw, clear the
-   * appropriate fields. */
-  if (NEWLY_ENABLED(EVENT_STREAM_BANDWIDTH_USED)) {
-    SMARTLIST_FOREACH(conns, connection_t *, conn,
-    {
-      if (conn->type == CONN_TYPE_AP) {
-        edge_connection_t *edge_conn = TO_EDGE_CONN(conn);
-        edge_conn->n_written = edge_conn->n_read = 0;
-      }
-    });
-  }
-  if (NEWLY_ENABLED(EVENT_CIRC_BANDWIDTH_USED)) {
-    clear_circ_bw_fields();
-  }
-  if (NEWLY_ENABLED(EVENT_BANDWIDTH_USED)) {
-    uint64_t r, w;
-    control_get_bytes_rw_last_sec(&r, &w);
-  }
-  if (any_old_per_sec_events != control_any_per_second_event_enabled()) {
-    rescan_periodic_events(get_options());
-  }
-
-#undef NEWLY_ENABLED
-}
-
-/** Adjust the log severities that result in control_event_logmsg being called
- * to match the severity of log messages that any controllers are interested
- * in. */
-void
-control_adjust_event_log_severity(void)
-{
-  int i;
-  int min_log_event=EVENT_ERR_MSG, max_log_event=EVENT_DEBUG_MSG;
-
-  for (i = EVENT_DEBUG_MSG; i <= EVENT_ERR_MSG; ++i) {
-    if (EVENT_IS_INTERESTING(i)) {
-      min_log_event = i;
-      break;
-    }
-  }
-  for (i = EVENT_ERR_MSG; i >= EVENT_DEBUG_MSG; --i) {
-    if (EVENT_IS_INTERESTING(i)) {
-      max_log_event = i;
-      break;
-    }
-  }
-  if (EVENT_IS_INTERESTING(EVENT_STATUS_GENERAL)) {
-    if (min_log_event > EVENT_NOTICE_MSG)
-      min_log_event = EVENT_NOTICE_MSG;
-    if (max_log_event < EVENT_ERR_MSG)
-      max_log_event = EVENT_ERR_MSG;
-  }
-  if (min_log_event <= max_log_event)
-    change_callback_log_severity(event_to_log_severity(min_log_event),
-                                 event_to_log_severity(max_log_event),
-                                 control_event_logmsg);
-  else
-    change_callback_log_severity(LOG_ERR, LOG_ERR,
-                                 control_event_logmsg);
-}
-
-/** Return true iff the event with code <b>c</b> is being sent to any current
- * control connection.  This is useful if the amount of work needed to prepare
- * to call the appropriate control_event_...() function is high.
- */
-int
-control_event_is_interesting(int event)
-{
-  return EVENT_IS_INTERESTING(event);
-}
-
-/** Return true if any event that needs to fire once a second is enabled. */
-int
-control_any_per_second_event_enabled(void)
-{
-  return ANY_EVENT_IS_INTERESTING(
-      EVENT_MASK_(EVENT_BANDWIDTH_USED) |
-      EVENT_MASK_(EVENT_CELL_STATS) |
-      EVENT_MASK_(EVENT_CIRC_BANDWIDTH_USED) |
-      EVENT_MASK_(EVENT_CONN_BW) |
-      EVENT_MASK_(EVENT_STREAM_BANDWIDTH_USED)
-  );
-}
-
-/* The value of 'get_bytes_read()' the previous time that
- * control_get_bytes_rw_last_sec() as called. */
-static uint64_t stats_prev_n_read = 0;
-/* The value of 'get_bytes_written()' the previous time that
- * control_get_bytes_rw_last_sec() as called. */
-static uint64_t stats_prev_n_written = 0;
-
-/**
- * Set <b>n_read</b> and <b>n_written</b> to the total number of bytes read
- * and written by Tor since the last call to this function.
- *
- * Call this only from the main thread.
- */
-static void
-control_get_bytes_rw_last_sec(uint64_t *n_read,
-                              uint64_t *n_written)
-{
-  const uint64_t stats_n_bytes_read = get_bytes_read();
-  const uint64_t stats_n_bytes_written = get_bytes_written();
-
-  *n_read = stats_n_bytes_read - stats_prev_n_read;
-  *n_written = stats_n_bytes_written - stats_prev_n_written;
-  stats_prev_n_read = stats_n_bytes_read;
-  stats_prev_n_written = stats_n_bytes_written;
-}
-
-/**
- * Run all the controller events (if any) that are scheduled to trigger once
- * per second.
- */
-void
-control_per_second_events(void)
-{
-  if (!control_any_per_second_event_enabled())
-    return;
-
-  uint64_t bytes_read, bytes_written;
-  control_get_bytes_rw_last_sec(&bytes_read, &bytes_written);
-  control_event_bandwidth_used((uint32_t)bytes_read,(uint32_t)bytes_written);
-
-  control_event_stream_bandwidth_used();
-  control_event_conn_bandwidth_used();
-  control_event_circ_bandwidth_used();
-  control_event_circuit_cell_stats();
-}
-
-/** Append a NUL-terminated string <b>s</b> to the end of
- * <b>conn</b>-\>outbuf.
- */
-static inline void
-connection_write_str_to_buf(const char *s, control_connection_t *conn)
-{
-  size_t len = strlen(s);
-  connection_buf_add(s, len, TO_CONN(conn));
-}
-
-/** Given a <b>len</b>-character string in <b>data</b>, made of lines
- * terminated by CRLF, allocate a new string in *<b>out</b>, and copy the
- * contents of <b>data</b> into *<b>out</b>, adding a period before any period
- * that appears at the start of a line, and adding a period-CRLF line at
- * the end. Replace all LF characters sequences with CRLF.  Return the number
- * of bytes in *<b>out</b>.
- */
-STATIC size_t
-write_escaped_data(const char *data, size_t len, char **out)
-{
-  tor_assert(len < SIZE_MAX - 9);
-  size_t sz_out = len+8+1;
-  char *outp;
-  const char *start = data, *end;
-  size_t i;
-  int start_of_line;
-  for (i=0; i < len; ++i) {
-    if (data[i] == '\n') {
-      sz_out += 2; /* Maybe add a CR; maybe add a dot. */
-      if (sz_out >= SIZE_T_CEILING) {
-        log_warn(LD_BUG, "Input to write_escaped_data was too long");
-        *out = tor_strdup(".\r\n");
-        return 3;
-      }
-    }
-  }
-  *out = outp = tor_malloc(sz_out);
-  end = data+len;
-  start_of_line = 1;
-  while (data < end) {
-    if (*data == '\n') {
-      if (data > start && data[-1] != '\r')
-        *outp++ = '\r';
-      start_of_line = 1;
-    } else if (*data == '.') {
-      if (start_of_line) {
-        start_of_line = 0;
-        *outp++ = '.';
-      }
-    } else {
-      start_of_line = 0;
-    }
-    *outp++ = *data++;
-  }
-  if (outp < *out+2 || fast_memcmp(outp-2, "\r\n", 2)) {
-    *outp++ = '\r';
-    *outp++ = '\n';
-  }
-  *outp++ = '.';
-  *outp++ = '\r';
-  *outp++ = '\n';
-  *outp = '\0'; /* NUL-terminate just in case. */
-  tor_assert(outp >= *out);
-  tor_assert((size_t)(outp - *out) <= sz_out);
-  return outp - *out;
-}
-
-/** Given a <b>len</b>-character string in <b>data</b>, made of lines
- * terminated by CRLF, allocate a new string in *<b>out</b>, and copy
- * the contents of <b>data</b> into *<b>out</b>, removing any period
- * that appears at the start of a line, and replacing all CRLF sequences
- * with LF.   Return the number of
- * bytes in *<b>out</b>. */
-STATIC size_t
-read_escaped_data(const char *data, size_t len, char **out)
-{
-  char *outp;
-  const char *next;
-  const char *end;
-
-  *out = outp = tor_malloc(len+1);
-
-  end = data+len;
-
-  while (data < end) {
-    /* we're at the start of a line. */
-    if (*data == '.')
-      ++data;
-    next = memchr(data, '\n', end-data);
-    if (next) {
-      size_t n_to_copy = next-data;
-      /* Don't copy a CR that precedes this LF. */
-      if (n_to_copy && *(next-1) == '\r')
-        --n_to_copy;
-      memcpy(outp, data, n_to_copy);
-      outp += n_to_copy;
-      data = next+1; /* This will point at the start of the next line,
-                      * or the end of the string, or a period. */
-    } else {
-      memcpy(outp, data, end-data);
-      outp += (end-data);
-      *outp = '\0';
-      return outp - *out;
-    }
-    *outp++ = '\n';
-  }
-
-  *outp = '\0';
-  return outp - *out;
-}
-
-/** If the first <b>in_len_max</b> characters in <b>start</b> contain a
- * double-quoted string with escaped characters, return the length of that
- * string (as encoded, including quotes).  Otherwise return -1. */
-static inline int
-get_escaped_string_length(const char *start, size_t in_len_max,
-                          int *chars_out)
-{
-  const char *cp, *end;
-  int chars = 0;
-
-  if (*start != '\"')
-    return -1;
-
-  cp = start+1;
-  end = start+in_len_max;
-
-  /* Calculate length. */
-  while (1) {
-    if (cp >= end) {
-      return -1; /* Too long. */
-    } else if (*cp == '\\') {
-      if (++cp == end)
-        return -1; /* Can't escape EOS. */
-      ++cp;
-      ++chars;
-    } else if (*cp == '\"') {
-      break;
-    } else {
-      ++cp;
-      ++chars;
-    }
-  }
-  if (chars_out)
-    *chars_out = chars;
-  return (int)(cp - start+1);
-}
-
-/** As decode_escaped_string, but does not decode the string: copies the
- * entire thing, including quotation marks. */
-static const char *
-extract_escaped_string(const char *start, size_t in_len_max,
-                       char **out, size_t *out_len)
-{
-  int length = get_escaped_string_length(start, in_len_max, NULL);
-  if (length<0)
-    return NULL;
-  *out_len = length;
-  *out = tor_strndup(start, *out_len);
-  return start+length;
-}
-
-/** Given a pointer to a string starting at <b>start</b> containing
- * <b>in_len_max</b> characters, decode a string beginning with one double
- * quote, containing any number of non-quote characters or characters escaped
- * with a backslash, and ending with a final double quote.  Place the resulting
- * string (unquoted, unescaped) into a newly allocated string in *<b>out</b>;
- * store its length in <b>out_len</b>.  On success, return a pointer to the
- * character immediately following the escaped string.  On failure, return
- * NULL. */
-static const char *
-decode_escaped_string(const char *start, size_t in_len_max,
-                   char **out, size_t *out_len)
-{
-  const char *cp, *end;
-  char *outp;
-  int len, n_chars = 0;
-
-  len = get_escaped_string_length(start, in_len_max, &n_chars);
-  if (len<0)
-    return NULL;
-
-  end = start+len-1; /* Index of last quote. */
-  tor_assert(*end == '\"');
-  outp = *out = tor_malloc(len+1);
-  *out_len = n_chars;
-
-  cp = start+1;
-  while (cp < end) {
-    if (*cp == '\\')
-      ++cp;
-    *outp++ = *cp++;
-  }
-  *outp = '\0';
-  tor_assert((outp - *out) == (int)*out_len);
-
-  return end+1;
-}
-
 /** Create and add a new controller connection on <b>sock</b>.  If
  * <b>CC_LOCAL_FD_IS_OWNER</b> is set in <b>flags</b>, this Tor process should
  * exit when the connection closes.  If <b>CC_LOCAL_FD_IS_AUTHENTICATED</b>
@@ -716,29 +113,6 @@ control_connection_add_local_fd(tor_socket_t sock, unsigned flags)
   return 0;
 }
 
-/** Acts like sprintf, but writes its formatted string to the end of
- * <b>conn</b>-\>outbuf. */
-static void
-connection_printf_to_buf(control_connection_t *conn, const char *format, ...)
-{
-  va_list ap;
-  char *buf = NULL;
-  int len;
-
-  va_start(ap,format);
-  len = tor_vasprintf(&buf, format, ap);
-  va_end(ap);
-
-  if (len < 0) {
-    log_err(LD_BUG, "Unable to format string for controller.");
-    tor_assert(0);
-  }
-
-  connection_buf_add(buf, (size_t)len, TO_CONN(conn));
-
-  tor_free(buf);
-}
-
 /** Write all of the open control ports to ControlPortWriteToFile */
 void
 control_ports_write_to_file(void)
@@ -783,6178 +157,345 @@ control_ports_write_to_file(void)
   smartlist_free(lines);
 }
 
-/** Send a "DONE" message down the control connection <b>conn</b>. */
-static void
-send_control_done(control_connection_t *conn)
+const struct signal_name_t signal_table[] = {
+  { SIGHUP, "RELOAD" },
+  { SIGHUP, "HUP" },
+  { SIGINT, "SHUTDOWN" },
+  { SIGUSR1, "DUMP" },
+  { SIGUSR1, "USR1" },
+  { SIGUSR2, "DEBUG" },
+  { SIGUSR2, "USR2" },
+  { SIGTERM, "HALT" },
+  { SIGTERM, "TERM" },
+  { SIGTERM, "INT" },
+  { SIGNEWNYM, "NEWNYM" },
+  { SIGCLEARDNSCACHE, "CLEARDNSCACHE"},
+  { SIGHEARTBEAT, "HEARTBEAT"},
+  { SIGACTIVE, "ACTIVE" },
+  { SIGDORMANT, "DORMANT" },
+  { 0, NULL },
+};
+
+/** Called when <b>conn</b> has no more bytes left on its outbuf. */
+int
+connection_control_finished_flushing(control_connection_t *conn)
 {
-  connection_write_str_to_buf("250 OK\r\n", conn);
+  tor_assert(conn);
+  return 0;
 }
 
-/** Represents an event that's queued to be sent to one or more
- * controllers. */
-typedef struct queued_event_s {
-  uint16_t event;
-  char *msg;
-} queued_event_t;
-
-/** Pointer to int. If this is greater than 0, we don't allow new events to be
- * queued. */
-static tor_threadlocal_t block_event_queue_flag;
-
-/** Holds a smartlist of queued_event_t objects that may need to be sent
- * to one or more controllers */
-static smartlist_t *queued_control_events = NULL;
+/** Called when <b>conn</b> has gotten its socket closed. */
+int
+connection_control_reached_eof(control_connection_t *conn)
+{
+  tor_assert(conn);
 
-/** True if the flush_queued_events_event is pending. */
-static int flush_queued_event_pending = 0;
+  log_info(LD_CONTROL,"Control connection reached EOF. Closing.");
+  connection_mark_for_close(TO_CONN(conn));
+  return 0;
+}
 
-/** Lock to protect the above fields. */
-static tor_mutex_t *queued_control_events_lock = NULL;
+/** Shut down this Tor instance in the same way that SIGINT would, but
+ * with a log message appropriate for the loss of an owning controller. */
+static void
+lost_owning_controller(const char *owner_type, const char *loss_manner)
+{
+  log_notice(LD_CONTROL, "Owning controller %s has %s -- exiting now.",
+             owner_type, loss_manner);
 
-/** An event that should fire in order to flush the contents of
- * queued_control_events. */
-static mainloop_event_t *flush_queued_events_event = NULL;
+  activate_signal(SIGTERM);
+}
 
+/** Called when <b>conn</b> is being freed. */
 void
-control_initialize_event_queue(void)
+connection_control_closed(control_connection_t *conn)
 {
-  if (queued_control_events == NULL) {
-    queued_control_events = smartlist_new();
-  }
+  tor_assert(conn);
 
-  if (flush_queued_events_event == NULL) {
-    struct event_base *b = tor_libevent_get_base();
-    if (b) {
-      flush_queued_events_event =
-        mainloop_event_new(flush_queued_events_cb, NULL);
-      tor_assert(flush_queued_events_event);
-    }
+  conn->event_mask = 0;
+  control_update_global_event_mask();
+
+  /* Close all ephemeral Onion Services if any.
+   * The list and it's contents are scrubbed/freed in connection_free_.
+   */
+  if (conn->ephemeral_onion_services) {
+    SMARTLIST_FOREACH_BEGIN(conn->ephemeral_onion_services, char *, cp) {
+      if (rend_valid_v2_service_id(cp)) {
+        rend_service_del_ephemeral(cp);
+      } else if (hs_address_is_valid(cp)) {
+        hs_service_del_ephemeral(cp);
+      } else {
+        /* An invalid .onion in our list should NEVER happen */
+        tor_fragile_assert();
+      }
+    } SMARTLIST_FOREACH_END(cp);
   }
 
-  if (queued_control_events_lock == NULL) {
-    queued_control_events_lock = tor_mutex_new();
-    tor_threadlocal_init(&block_event_queue_flag);
+  if (conn->is_owning_control_connection) {
+    lost_owning_controller("connection", "closed");
   }
 }
 
-static int *
-get_block_event_queue(void)
+/** Return true iff <b>cmd</b> is allowable (or at least forgivable) at this
+ * stage of the protocol. */
+static int
+is_valid_initial_command(control_connection_t *conn, const char *cmd)
 {
-  int *val = tor_threadlocal_get(&block_event_queue_flag);
-  if (PREDICT_UNLIKELY(val == NULL)) {
-    val = tor_malloc_zero(sizeof(int));
-    tor_threadlocal_set(&block_event_queue_flag, val);
-  }
-  return val;
+  if (conn->base_.state == CONTROL_CONN_STATE_OPEN)
+    return 1;
+  if (!strcasecmp(cmd, "PROTOCOLINFO"))
+    return (!conn->have_sent_protocolinfo &&
+            conn->safecookie_client_hash == NULL);
+  if (!strcasecmp(cmd, "AUTHCHALLENGE"))
+    return (conn->safecookie_client_hash == NULL);
+  if (!strcasecmp(cmd, "AUTHENTICATE") ||
+      !strcasecmp(cmd, "QUIT"))
+    return 1;
+  return 0;
 }
 
-/** Helper: inserts an event on the list of events queued to be sent to
- * one or more controllers, and schedules the events to be flushed if needed.
- *
- * This function takes ownership of <b>msg</b>, and may free it.
- *
- * We queue these events rather than send them immediately in order to break
- * the dependency in our callgraph from code that generates events for the
- * controller, and the network layer at large.  Otherwise, nearly every
- * interesting part of Tor would potentially call every other interesting part
- * of Tor.
+/** Do not accept any control command of more than 1MB in length.  Anything
+ * that needs to be anywhere near this long probably means that one of our
+ * interfaces is broken. */
+#define MAX_COMMAND_LINE_LENGTH (1024*1024)
+
+/** Wrapper around peek_buf_has_control0 command: presents the same
+ * interface as that underlying functions, but takes a connection_t intead of
+ * a buf_t.
  */
-MOCK_IMPL(STATIC void,
-queue_control_event_string,(uint16_t event, char *msg))
+static int
+peek_connection_has_control0_command(connection_t *conn)
 {
-  /* This is redundant with checks done elsewhere, but it's a last-ditch
-   * attempt to avoid queueing something we shouldn't have to queue. */
-  if (PREDICT_UNLIKELY( ! EVENT_IS_INTERESTING(event) )) {
-    tor_free(msg);
-    return;
-  }
+  return peek_buf_has_control0_command(conn->inbuf);
+}
 
-  int *block_event_queue = get_block_event_queue();
-  if (*block_event_queue) {
-    tor_free(msg);
-    return;
-  }
-
-  queued_event_t *ev = tor_malloc(sizeof(*ev));
-  ev->event = event;
-  ev->msg = msg;
-
-  /* No queueing an event while queueing an event */
-  ++*block_event_queue;
-
-  tor_mutex_acquire(queued_control_events_lock);
-  tor_assert(queued_control_events);
-  smartlist_add(queued_control_events, ev);
-
-  int activate_event = 0;
-  if (! flush_queued_event_pending && in_main_thread()) {
-    activate_event = 1;
-    flush_queued_event_pending = 1;
-  }
-
-  tor_mutex_release(queued_control_events_lock);
-
-  --*block_event_queue;
-
-  /* We just put an event on the queue; mark the queue to be
-   * flushed.  We only do this from the main thread for now; otherwise,
-   * we'd need to incur locking overhead in Libevent or use a socket.
-   */
-  if (activate_event) {
-    tor_assert(flush_queued_events_event);
-    mainloop_event_activate(flush_queued_events_event);
-  }
-}
-
-#define queued_event_free(ev) \
-  FREE_AND_NULL(queued_event_t, queued_event_free_, (ev))
-
-/** Release all storage held by <b>ev</b>. */
-static void
-queued_event_free_(queued_event_t *ev)
-{
-  if (ev == NULL)
-    return;
-
-  tor_free(ev->msg);
-  tor_free(ev);
-}
-
-/** Send every queued event to every controller that's interested in it,
- * and remove the events from the queue.  If <b>force</b> is true,
- * then make all controllers send their data out immediately, since we
- * may be about to shut down. */
-static void
-queued_events_flush_all(int force)
-{
-  /* Make sure that we get all the pending log events, if there are any. */
-  flush_pending_log_callbacks();
-
-  if (PREDICT_UNLIKELY(queued_control_events == NULL)) {
-    return;
-  }
-  smartlist_t *all_conns = get_connection_array();
-  smartlist_t *controllers = smartlist_new();
-  smartlist_t *queued_events;
-
-  int *block_event_queue = get_block_event_queue();
-  ++*block_event_queue;
-
-  tor_mutex_acquire(queued_control_events_lock);
-  /* No queueing an event while flushing events. */
-  flush_queued_event_pending = 0;
-  queued_events = queued_control_events;
-  queued_control_events = smartlist_new();
-  tor_mutex_release(queued_control_events_lock);
-
-  /* Gather all the controllers that will care... */
-  SMARTLIST_FOREACH_BEGIN(all_conns, connection_t *, conn) {
-    if (conn->type == CONN_TYPE_CONTROL &&
-        !conn->marked_for_close &&
-        conn->state == CONTROL_CONN_STATE_OPEN) {
-      control_connection_t *control_conn = TO_CONTROL_CONN(conn);
-
-      smartlist_add(controllers, control_conn);
-    }
-  } SMARTLIST_FOREACH_END(conn);
-
-  SMARTLIST_FOREACH_BEGIN(queued_events, queued_event_t *, ev) {
-    const event_mask_t bit = ((event_mask_t)1) << ev->event;
-    const size_t msg_len = strlen(ev->msg);
-    SMARTLIST_FOREACH_BEGIN(controllers, control_connection_t *,
-                            control_conn) {
-      if (control_conn->event_mask & bit) {
-        connection_buf_add(ev->msg, msg_len, TO_CONN(control_conn));
-      }
-    } SMARTLIST_FOREACH_END(control_conn);
-
-    queued_event_free(ev);
-  } SMARTLIST_FOREACH_END(ev);
-
-  if (force) {
-    SMARTLIST_FOREACH_BEGIN(controllers, control_connection_t *,
-                            control_conn) {
-      connection_flush(TO_CONN(control_conn));
-    } SMARTLIST_FOREACH_END(control_conn);
-  }
-
-  smartlist_free(queued_events);
-  smartlist_free(controllers);
-
-  --*block_event_queue;
-}
-
-/** Libevent callback: Flushes pending events to controllers that are
- * interested in them. */
-static void
-flush_queued_events_cb(mainloop_event_t *event, void *arg)
-{
-  (void) event;
-  (void) arg;
-  queued_events_flush_all(0);
-}
-
-/** Send an event to all v1 controllers that are listening for code
- * <b>event</b>.  The event's body is given by <b>msg</b>.
- *
- * The EXTENDED_FORMAT and NONEXTENDED_FORMAT flags behave similarly with
- * respect to the EXTENDED_EVENTS feature. */
-MOCK_IMPL(STATIC void,
-send_control_event_string,(uint16_t event,
-                           const char *msg))
-{
-  tor_assert(event >= EVENT_MIN_ && event <= EVENT_MAX_);
-  queue_control_event_string(event, tor_strdup(msg));
-}
-
-/** Helper for send_control_event and control_event_status:
- * Send an event to all v1 controllers that are listening for code
- * <b>event</b>.  The event's body is created by the printf-style format in
- * <b>format</b>, and other arguments as provided. */
-static void
-send_control_event_impl(uint16_t event,
-                        const char *format, va_list ap)
-{
-  char *buf = NULL;
-  int len;
-
-  len = tor_vasprintf(&buf, format, ap);
-  if (len < 0) {
-    log_warn(LD_BUG, "Unable to format event for controller.");
-    return;
-  }
-
-  queue_control_event_string(event, buf);
-}
-
-/** Send an event to all v1 controllers that are listening for code
- * <b>event</b>.  The event's body is created by the printf-style format in
- * <b>format</b>, and other arguments as provided. */
-static void
-send_control_event(uint16_t event,
-                   const char *format, ...)
-{
-  va_list ap;
-  va_start(ap, format);
-  send_control_event_impl(event, format, ap);
-  va_end(ap);
-}
-
-/** Given a text circuit <b>id</b>, return the corresponding circuit. */
-static origin_circuit_t *
-get_circ(const char *id)
-{
-  uint32_t n_id;
-  int ok;
-  n_id = (uint32_t) tor_parse_ulong(id, 10, 0, UINT32_MAX, &ok, NULL);
-  if (!ok)
-    return NULL;
-  return circuit_get_by_global_id(n_id);
-}
-
-/** Given a text stream <b>id</b>, return the corresponding AP connection. */
-static entry_connection_t *
-get_stream(const char *id)
-{
-  uint64_t n_id;
-  int ok;
-  connection_t *conn;
-  n_id = tor_parse_uint64(id, 10, 0, UINT64_MAX, &ok, NULL);
-  if (!ok)
-    return NULL;
-  conn = connection_get_by_global_id(n_id);
-  if (!conn || conn->type != CONN_TYPE_AP || conn->marked_for_close)
-    return NULL;
-  return TO_ENTRY_CONN(conn);
-}
-
-/** Helper for setconf and resetconf. Acts like setconf, except
- * it passes <b>use_defaults</b> on to options_trial_assign().  Modifies the
- * contents of body.
- */
-static int
-control_setconf_helper(control_connection_t *conn, uint32_t len, char *body,
-                       int use_defaults)
-{
-  setopt_err_t opt_err;
-  config_line_t *lines=NULL;
-  char *start = body;
-  char *errstring = NULL;
-  const unsigned flags =
-    CAL_CLEAR_FIRST | (use_defaults ? CAL_USE_DEFAULTS : 0);
-
-  char *config;
-  smartlist_t *entries = smartlist_new();
-
-  /* We have a string, "body", of the format '(key(=val|="val")?)' entries
-   * separated by space.  break it into a list of configuration entries. */
-  while (*body) {
-    char *eq = body;
-    char *key;
-    char *entry;
-    while (!TOR_ISSPACE(*eq) && *eq != '=')
-      ++eq;
-    key = tor_strndup(body, eq-body);
-    body = eq+1;
-    if (*eq == '=') {
-      char *val=NULL;
-      size_t val_len=0;
-      if (*body != '\"') {
-        char *val_start = body;
-        while (!TOR_ISSPACE(*body))
-          body++;
-        val = tor_strndup(val_start, body-val_start);
-        val_len = strlen(val);
-      } else {
-        body = (char*)extract_escaped_string(body, (len - (body-start)),
-                                             &val, &val_len);
-        if (!body) {
-          connection_write_str_to_buf("551 Couldn't parse string\r\n", conn);
-          SMARTLIST_FOREACH(entries, char *, cp, tor_free(cp));
-          smartlist_free(entries);
-          tor_free(key);
-          return 0;
-        }
-      }
-      tor_asprintf(&entry, "%s %s", key, val);
-      tor_free(key);
-      tor_free(val);
-    } else {
-      entry = key;
-    }
-    smartlist_add(entries, entry);
-    while (TOR_ISSPACE(*body))
-      ++body;
-  }
-
-  smartlist_add_strdup(entries, "");
-  config = smartlist_join_strings(entries, "\n", 0, NULL);
-  SMARTLIST_FOREACH(entries, char *, cp, tor_free(cp));
-  smartlist_free(entries);
-
-  if (config_get_lines(config, &lines, 0) < 0) {
-    log_warn(LD_CONTROL,"Controller gave us config lines we can't parse.");
-    connection_write_str_to_buf("551 Couldn't parse configuration\r\n",
-                                conn);
-    tor_free(config);
-    return 0;
-  }
-  tor_free(config);
-
-  opt_err = options_trial_assign(lines, flags, &errstring);
-  {
-    const char *msg;
-    switch (opt_err) {
-      case SETOPT_ERR_MISC:
-        msg = "552 Unrecognized option";
-        break;
-      case SETOPT_ERR_PARSE:
-        msg = "513 Unacceptable option value";
-        break;
-      case SETOPT_ERR_TRANSITION:
-        msg = "553 Transition not allowed";
-        break;
-      case SETOPT_ERR_SETTING:
-      default:
-        msg = "553 Unable to set option";
-        break;
-      case SETOPT_OK:
-        config_free_lines(lines);
-        send_control_done(conn);
-        return 0;
-    }
-    log_warn(LD_CONTROL,
-             "Controller gave us config lines that didn't validate: %s",
-             errstring);
-    connection_printf_to_buf(conn, "%s: %s\r\n", msg, errstring);
-    config_free_lines(lines);
-    tor_free(errstring);
-    return 0;
-  }
-}
-
-/** Called when we receive a SETCONF message: parse the body and try
- * to update our configuration.  Reply with a DONE or ERROR message.
- * Modifies the contents of body.*/
-static int
-handle_control_setconf(control_connection_t *conn, uint32_t len, char *body)
-{
-  return control_setconf_helper(conn, len, body, 0);
-}
-
-/** Called when we receive a RESETCONF message: parse the body and try
- * to update our configuration.  Reply with a DONE or ERROR message.
- * Modifies the contents of body. */
-static int
-handle_control_resetconf(control_connection_t *conn, uint32_t len, char *body)
-{
-  return control_setconf_helper(conn, len, body, 1);
-}
-
-/** Called when we receive a GETCONF message.  Parse the request, and
- * reply with a CONFVALUE or an ERROR message */
-static int
-handle_control_getconf(control_connection_t *conn, uint32_t body_len,
-                       const char *body)
-{
-  smartlist_t *questions = smartlist_new();
-  smartlist_t *answers = smartlist_new();
-  smartlist_t *unrecognized = smartlist_new();
-  char *msg = NULL;
-  size_t msg_len;
-  const or_options_t *options = get_options();
-  int i, len;
-
-  (void) body_len; /* body is NUL-terminated; so we can ignore len. */
-  smartlist_split_string(questions, body, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-  SMARTLIST_FOREACH_BEGIN(questions, const char *, q) {
-    if (!option_is_recognized(q)) {
-      smartlist_add(unrecognized, (char*) q);
-    } else {
-      config_line_t *answer = option_get_assignment(options,q);
-      if (!answer) {
-        const char *name = option_get_canonical_name(q);
-        smartlist_add_asprintf(answers, "250-%s\r\n", name);
-      }
-
-      while (answer) {
-        config_line_t *next;
-        smartlist_add_asprintf(answers, "250-%s=%s\r\n",
-                     answer->key, answer->value);
-
-        next = answer->next;
-        tor_free(answer->key);
-        tor_free(answer->value);
-        tor_free(answer);
-        answer = next;
-      }
-    }
-  } SMARTLIST_FOREACH_END(q);
-
-  if ((len = smartlist_len(unrecognized))) {
-    for (i=0; i < len-1; ++i)
-      connection_printf_to_buf(conn,
-                               "552-Unrecognized configuration key \"%s\"\r\n",
-                               (char*)smartlist_get(unrecognized, i));
-    connection_printf_to_buf(conn,
-                             "552 Unrecognized configuration key \"%s\"\r\n",
-                             (char*)smartlist_get(unrecognized, len-1));
-  } else if ((len = smartlist_len(answers))) {
-    char *tmp = smartlist_get(answers, len-1);
-    tor_assert(strlen(tmp)>4);
-    tmp[3] = ' ';
-    msg = smartlist_join_strings(answers, "", 0, &msg_len);
-    connection_buf_add(msg, msg_len, TO_CONN(conn));
-  } else {
-    connection_write_str_to_buf("250 OK\r\n", conn);
-  }
-
-  SMARTLIST_FOREACH(answers, char *, cp, tor_free(cp));
-  smartlist_free(answers);
-  SMARTLIST_FOREACH(questions, char *, cp, tor_free(cp));
-  smartlist_free(questions);
-  smartlist_free(unrecognized);
-
-  tor_free(msg);
-
-  return 0;
-}
-
-/** Called when we get a +LOADCONF message. */
-static int
-handle_control_loadconf(control_connection_t *conn, uint32_t len,
-                         const char *body)
-{
-  setopt_err_t retval;
-  char *errstring = NULL;
-  const char *msg = NULL;
-  (void) len;
-
-  retval = options_init_from_string(NULL, body, CMD_RUN_TOR, NULL, &errstring);
-
-  if (retval != SETOPT_OK)
-    log_warn(LD_CONTROL,
-             "Controller gave us config file that didn't validate: %s",
-             errstring);
-
-  switch (retval) {
-  case SETOPT_ERR_PARSE:
-    msg = "552 Invalid config file";
-    break;
-  case SETOPT_ERR_TRANSITION:
-    msg = "553 Transition not allowed";
-    break;
-  case SETOPT_ERR_SETTING:
-    msg = "553 Unable to set option";
-    break;
-  case SETOPT_ERR_MISC:
-  default:
-    msg = "550 Unable to load config";
-    break;
-  case SETOPT_OK:
-    break;
-  }
-  if (msg) {
-    if (errstring)
-      connection_printf_to_buf(conn, "%s: %s\r\n", msg, errstring);
-    else
-      connection_printf_to_buf(conn, "%s\r\n", msg);
-  } else {
-    send_control_done(conn);
-  }
-  tor_free(errstring);
-  return 0;
-}
-
-/** Helper structure: maps event values to their names. */
-struct control_event_t {
-  uint16_t event_code;
-  const char *event_name;
-};
-/** Table mapping event values to their names.  Used to implement SETEVENTS
- * and GETINFO events/names, and to keep they in sync. */
-static const struct control_event_t control_event_table[] = {
-  { EVENT_CIRCUIT_STATUS, "CIRC" },
-  { EVENT_CIRCUIT_STATUS_MINOR, "CIRC_MINOR" },
-  { EVENT_STREAM_STATUS, "STREAM" },
-  { EVENT_OR_CONN_STATUS, "ORCONN" },
-  { EVENT_BANDWIDTH_USED, "BW" },
-  { EVENT_DEBUG_MSG, "DEBUG" },
-  { EVENT_INFO_MSG, "INFO" },
-  { EVENT_NOTICE_MSG, "NOTICE" },
-  { EVENT_WARN_MSG, "WARN" },
-  { EVENT_ERR_MSG, "ERR" },
-  { EVENT_NEW_DESC, "NEWDESC" },
-  { EVENT_ADDRMAP, "ADDRMAP" },
-  { EVENT_DESCCHANGED, "DESCCHANGED" },
-  { EVENT_NS, "NS" },
-  { EVENT_STATUS_GENERAL, "STATUS_GENERAL" },
-  { EVENT_STATUS_CLIENT, "STATUS_CLIENT" },
-  { EVENT_STATUS_SERVER, "STATUS_SERVER" },
-  { EVENT_GUARD, "GUARD" },
-  { EVENT_STREAM_BANDWIDTH_USED, "STREAM_BW" },
-  { EVENT_CLIENTS_SEEN, "CLIENTS_SEEN" },
-  { EVENT_NEWCONSENSUS, "NEWCONSENSUS" },
-  { EVENT_BUILDTIMEOUT_SET, "BUILDTIMEOUT_SET" },
-  { EVENT_GOT_SIGNAL, "SIGNAL" },
-  { EVENT_CONF_CHANGED, "CONF_CHANGED"},
-  { EVENT_CONN_BW, "CONN_BW" },
-  { EVENT_CELL_STATS, "CELL_STATS" },
-  { EVENT_CIRC_BANDWIDTH_USED, "CIRC_BW" },
-  { EVENT_TRANSPORT_LAUNCHED, "TRANSPORT_LAUNCHED" },
-  { EVENT_HS_DESC, "HS_DESC" },
-  { EVENT_HS_DESC_CONTENT, "HS_DESC_CONTENT" },
-  { EVENT_NETWORK_LIVENESS, "NETWORK_LIVENESS" },
-  { 0, NULL },
-};
-
-/** Called when we get a SETEVENTS message: update conn->event_mask,
- * and reply with DONE or ERROR. */
-static int
-handle_control_setevents(control_connection_t *conn, uint32_t len,
-                         const char *body)
-{
-  int event_code;
-  event_mask_t event_mask = 0;
-  smartlist_t *events = smartlist_new();
-
-  (void) len;
-
-  smartlist_split_string(events, body, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-  SMARTLIST_FOREACH_BEGIN(events, const char *, ev)
-    {
-      if (!strcasecmp(ev, "EXTENDED") ||
-          !strcasecmp(ev, "AUTHDIR_NEWDESCS")) {
-        log_warn(LD_CONTROL, "The \"%s\" SETEVENTS argument is no longer "
-                 "supported.", ev);
-        continue;
-      } else {
-        int i;
-        event_code = -1;
-
-        for (i = 0; control_event_table[i].event_name != NULL; ++i) {
-          if (!strcasecmp(ev, control_event_table[i].event_name)) {
-            event_code = control_event_table[i].event_code;
-            break;
-          }
-        }
-
-        if (event_code == -1) {
-          connection_printf_to_buf(conn, "552 Unrecognized event \"%s\"\r\n",
-                                   ev);
-          SMARTLIST_FOREACH(events, char *, e, tor_free(e));
-          smartlist_free(events);
-          return 0;
-        }
-      }
-      event_mask |= (((event_mask_t)1) << event_code);
-    }
-  SMARTLIST_FOREACH_END(ev);
-  SMARTLIST_FOREACH(events, char *, e, tor_free(e));
-  smartlist_free(events);
-
-  conn->event_mask = event_mask;
-
-  control_update_global_event_mask();
-  send_control_done(conn);
-  return 0;
-}
-
-/** Decode the hashed, base64'd passwords stored in <b>passwords</b>.
- * Return a smartlist of acceptable passwords (unterminated strings of
- * length S2K_RFC2440_SPECIFIER_LEN+DIGEST_LEN) on success, or NULL on
- * failure.
- */
-smartlist_t *
-decode_hashed_passwords(config_line_t *passwords)
-{
-  char decoded[64];
-  config_line_t *cl;
-  smartlist_t *sl = smartlist_new();
-
-  tor_assert(passwords);
-
-  for (cl = passwords; cl; cl = cl->next) {
-    const char *hashed = cl->value;
-
-    if (!strcmpstart(hashed, "16:")) {
-      if (base16_decode(decoded, sizeof(decoded), hashed+3, strlen(hashed+3))
-                        != S2K_RFC2440_SPECIFIER_LEN + DIGEST_LEN
-          || strlen(hashed+3) != (S2K_RFC2440_SPECIFIER_LEN+DIGEST_LEN)*2) {
-        goto err;
-      }
-    } else {
-        if (base64_decode(decoded, sizeof(decoded), hashed, strlen(hashed))
-            != S2K_RFC2440_SPECIFIER_LEN+DIGEST_LEN) {
-          goto err;
-        }
-    }
-    smartlist_add(sl,
-                  tor_memdup(decoded, S2K_RFC2440_SPECIFIER_LEN+DIGEST_LEN));
-  }
-
-  return sl;
-
- err:
-  SMARTLIST_FOREACH(sl, char*, cp, tor_free(cp));
-  smartlist_free(sl);
-  return NULL;
-}
-
-/** Called when we get an AUTHENTICATE message.  Check whether the
- * authentication is valid, and if so, update the connection's state to
- * OPEN.  Reply with DONE or ERROR.
- */
-static int
-handle_control_authenticate(control_connection_t *conn, uint32_t len,
-                            const char *body)
-{
-  int used_quoted_string = 0;
-  const or_options_t *options = get_options();
-  const char *errstr = "Unknown error";
-  char *password;
-  size_t password_len;
-  const char *cp;
-  int i;
-  int bad_cookie=0, bad_password=0;
-  smartlist_t *sl = NULL;
-
-  if (!len) {
-    password = tor_strdup("");
-    password_len = 0;
-  } else if (TOR_ISXDIGIT(body[0])) {
-    cp = body;
-    while (TOR_ISXDIGIT(*cp))
-      ++cp;
-    i = (int)(cp - body);
-    tor_assert(i>0);
-    password_len = i/2;
-    password = tor_malloc(password_len + 1);
-    if (base16_decode(password, password_len+1, body, i)
-                      != (int) password_len) {
-      connection_write_str_to_buf(
-            "551 Invalid hexadecimal encoding.  Maybe you tried a plain text "
-            "password?  If so, the standard requires that you put it in "
-            "double quotes.\r\n", conn);
-      connection_mark_for_close(TO_CONN(conn));
-      tor_free(password);
-      return 0;
-    }
-  } else {
-    if (!decode_escaped_string(body, len, &password, &password_len)) {
-      connection_write_str_to_buf("551 Invalid quoted string.  You need "
-            "to put the password in double quotes.\r\n", conn);
-      connection_mark_for_close(TO_CONN(conn));
-      return 0;
-    }
-    used_quoted_string = 1;
-  }
-
-  if (conn->safecookie_client_hash != NULL) {
-    /* The controller has chosen safe cookie authentication; the only
-     * acceptable authentication value is the controller-to-server
-     * response. */
-
-    tor_assert(authentication_cookie_is_set);
-
-    if (password_len != DIGEST256_LEN) {
-      log_warn(LD_CONTROL,
-               "Got safe cookie authentication response with wrong length "
-               "(%d)", (int)password_len);
-      errstr = "Wrong length for safe cookie response.";
-      goto err;
-    }
-
-    if (tor_memneq(conn->safecookie_client_hash, password, DIGEST256_LEN)) {
-      log_warn(LD_CONTROL,
-               "Got incorrect safe cookie authentication response");
-      errstr = "Safe cookie response did not match expected value.";
-      goto err;
-    }
-
-    tor_free(conn->safecookie_client_hash);
-    goto ok;
-  }
-
-  if (!options->CookieAuthentication && !options->HashedControlPassword &&
-      !options->HashedControlSessionPassword) {
-    /* if Tor doesn't demand any stronger authentication, then
-     * the controller can get in with anything. */
-    goto ok;
-  }
-
-  if (options->CookieAuthentication) {
-    int also_password = options->HashedControlPassword != NULL ||
-      options->HashedControlSessionPassword != NULL;
-    if (password_len != AUTHENTICATION_COOKIE_LEN) {
-      if (!also_password) {
-        log_warn(LD_CONTROL, "Got authentication cookie with wrong length "
-                 "(%d)", (int)password_len);
-        errstr = "Wrong length on authentication cookie.";
-        goto err;
-      }
-      bad_cookie = 1;
-    } else if (tor_memneq(authentication_cookie, password, password_len)) {
-      if (!also_password) {
-        log_warn(LD_CONTROL, "Got mismatched authentication cookie");
-        errstr = "Authentication cookie did not match expected value.";
-        goto err;
-      }
-      bad_cookie = 1;
-    } else {
-      goto ok;
-    }
-  }
-
-  if (options->HashedControlPassword ||
-      options->HashedControlSessionPassword) {
-    int bad = 0;
-    smartlist_t *sl_tmp;
-    char received[DIGEST_LEN];
-    int also_cookie = options->CookieAuthentication;
-    sl = smartlist_new();
-    if (options->HashedControlPassword) {
-      sl_tmp = decode_hashed_passwords(options->HashedControlPassword);
-      if (!sl_tmp)
-        bad = 1;
-      else {
-        smartlist_add_all(sl, sl_tmp);
-        smartlist_free(sl_tmp);
-      }
-    }
-    if (options->HashedControlSessionPassword) {
-      sl_tmp = decode_hashed_passwords(options->HashedControlSessionPassword);
-      if (!sl_tmp)
-        bad = 1;
-      else {
-        smartlist_add_all(sl, sl_tmp);
-        smartlist_free(sl_tmp);
-      }
-    }
-    if (bad) {
-      if (!also_cookie) {
-        log_warn(LD_BUG,
-                 "Couldn't decode HashedControlPassword: invalid base16");
-        errstr="Couldn't decode HashedControlPassword value in configuration.";
-        goto err;
-      }
-      bad_password = 1;
-      SMARTLIST_FOREACH(sl, char *, str, tor_free(str));
-      smartlist_free(sl);
-      sl = NULL;
-    } else {
-      SMARTLIST_FOREACH(sl, char *, expected,
-      {
-        secret_to_key_rfc2440(received,DIGEST_LEN,
-                              password,password_len,expected);
-        if (tor_memeq(expected + S2K_RFC2440_SPECIFIER_LEN,
-                      received, DIGEST_LEN))
-          goto ok;
-      });
-      SMARTLIST_FOREACH(sl, char *, str, tor_free(str));
-      smartlist_free(sl);
-      sl = NULL;
-
-      if (used_quoted_string)
-        errstr = "Password did not match HashedControlPassword value from "
-          "configuration";
-      else
-        errstr = "Password did not match HashedControlPassword value from "
-          "configuration. Maybe you tried a plain text password? "
-          "If so, the standard requires that you put it in double quotes.";
-      bad_password = 1;
-      if (!also_cookie)
-        goto err;
-    }
-  }
-
-  /** We only get here if both kinds of authentication failed. */
-  tor_assert(bad_password && bad_cookie);
-  log_warn(LD_CONTROL, "Bad password or authentication cookie on controller.");
-  errstr = "Password did not match HashedControlPassword *or* authentication "
-    "cookie.";
-
- err:
-  tor_free(password);
-  connection_printf_to_buf(conn, "515 Authentication failed: %s\r\n", errstr);
-  connection_mark_for_close(TO_CONN(conn));
-  if (sl) { /* clean up */
-    SMARTLIST_FOREACH(sl, char *, str, tor_free(str));
-    smartlist_free(sl);
-  }
-  return 0;
- ok:
-  log_info(LD_CONTROL, "Authenticated control connection ("TOR_SOCKET_T_FORMAT
-           ")", conn->base_.s);
-  send_control_done(conn);
-  conn->base_.state = CONTROL_CONN_STATE_OPEN;
-  tor_free(password);
-  if (sl) { /* clean up */
-    SMARTLIST_FOREACH(sl, char *, str, tor_free(str));
-    smartlist_free(sl);
-  }
-  return 0;
-}
-
-/** Called when we get a SAVECONF command. Try to flush the current options to
- * disk, and report success or failure. */
-static int
-handle_control_saveconf(control_connection_t *conn, uint32_t len,
-                        const char *body)
-{
-  (void) len;
-
-  int force = !strcmpstart(body, "FORCE");
-  const or_options_t *options = get_options();
-  if ((!force && options->IncludeUsed) || options_save_current() < 0) {
-    connection_write_str_to_buf(
-      "551 Unable to write configuration to disk.\r\n", conn);
-  } else {
-    send_control_done(conn);
-  }
-  return 0;
-}
-
-struct signal_t {
-  int sig;
-  const char *signal_name;
-};
-
-static const struct signal_t signal_table[] = {
-  { SIGHUP, "RELOAD" },
-  { SIGHUP, "HUP" },
-  { SIGINT, "SHUTDOWN" },
-  { SIGUSR1, "DUMP" },
-  { SIGUSR1, "USR1" },
-  { SIGUSR2, "DEBUG" },
-  { SIGUSR2, "USR2" },
-  { SIGTERM, "HALT" },
-  { SIGTERM, "TERM" },
-  { SIGTERM, "INT" },
-  { SIGNEWNYM, "NEWNYM" },
-  { SIGCLEARDNSCACHE, "CLEARDNSCACHE"},
-  { SIGHEARTBEAT, "HEARTBEAT"},
-  { SIGACTIVE, "ACTIVE" },
-  { SIGDORMANT, "DORMANT" },
-  { 0, NULL },
-};
-
-/** Called when we get a SIGNAL command. React to the provided signal, and
- * report success or failure. (If the signal results in a shutdown, success
- * may not be reported.) */
-static int
-handle_control_signal(control_connection_t *conn, uint32_t len,
-                      const char *body)
-{
-  int sig = -1;
-  int i;
-  int n = 0;
-  char *s;
-
-  (void) len;
-
-  while (body[n] && ! TOR_ISSPACE(body[n]))
-    ++n;
-  s = tor_strndup(body, n);
-
-  for (i = 0; signal_table[i].signal_name != NULL; ++i) {
-    if (!strcasecmp(s, signal_table[i].signal_name)) {
-      sig = signal_table[i].sig;
-      break;
-    }
-  }
-
-  if (sig < 0)
-    connection_printf_to_buf(conn, "552 Unrecognized signal code \"%s\"\r\n",
-                             s);
-  tor_free(s);
-  if (sig < 0)
-    return 0;
-
-  send_control_done(conn);
-  /* Flush the "done" first if the signal might make us shut down. */
-  if (sig == SIGTERM || sig == SIGINT)
-    connection_flush(TO_CONN(conn));
-
-  activate_signal(sig);
-
-  return 0;
-}
-
-/** Called when we get a TAKEOWNERSHIP command.  Mark this connection
- * as an owning connection, so that we will exit if the connection
- * closes. */
-static int
-handle_control_takeownership(control_connection_t *conn, uint32_t len,
-                             const char *body)
-{
-  (void)len;
-  (void)body;
-
-  conn->is_owning_control_connection = 1;
-
-  log_info(LD_CONTROL, "Control connection %d has taken ownership of this "
-           "Tor instance.",
-           (int)(conn->base_.s));
-
-  send_control_done(conn);
-  return 0;
-}
-
-/** Called when we get a DROPOWNERSHIP command.  Mark this connection
- * as a non-owning connection, so that we will not exit if the connection
- * closes. */
-static int
-handle_control_dropownership(control_connection_t *conn, uint32_t len,
-                             const char *body)
-{
-  (void)len;
-  (void)body;
-
-  conn->is_owning_control_connection = 0;
-
-  log_info(LD_CONTROL, "Control connection %d has dropped ownership of this "
-           "Tor instance.",
-           (int)(conn->base_.s));
-
-  send_control_done(conn);
-  return 0;
-}
-
-/** Return true iff <b>addr</b> is unusable as a mapaddress target because of
- * containing funny characters. */
-static int
-address_is_invalid_mapaddress_target(const char *addr)
-{
-  if (!strcmpstart(addr, "*."))
-    return address_is_invalid_destination(addr+2, 1);
-  else
-    return address_is_invalid_destination(addr, 1);
-}
-
-/** Called when we get a MAPADDRESS command; try to bind all listed addresses,
- * and report success or failure. */
-static int
-handle_control_mapaddress(control_connection_t *conn, uint32_t len,
-                          const char *body)
-{
-  smartlist_t *elts;
-  smartlist_t *lines;
-  smartlist_t *reply;
-  char *r;
-  size_t sz;
-  (void) len; /* body is NUL-terminated, so it's safe to ignore the length. */
-
-  lines = smartlist_new();
-  elts = smartlist_new();
-  reply = smartlist_new();
-  smartlist_split_string(lines, body, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-  SMARTLIST_FOREACH_BEGIN(lines, char *, line) {
-    tor_strlower(line);
-    smartlist_split_string(elts, line, "=", 0, 2);
-    if (smartlist_len(elts) == 2) {
-      const char *from = smartlist_get(elts,0);
-      const char *to = smartlist_get(elts,1);
-      if (address_is_invalid_mapaddress_target(to)) {
-        smartlist_add_asprintf(reply,
-                     "512-syntax error: invalid address '%s'", to);
-        log_warn(LD_CONTROL,
-                 "Skipping invalid argument '%s' in MapAddress msg", to);
-      } else if (!strcmp(from, ".") || !strcmp(from, "0.0.0.0") ||
-                 !strcmp(from, "::")) {
-        const char type =
-          !strcmp(from,".") ? RESOLVED_TYPE_HOSTNAME :
-          (!strcmp(from, "0.0.0.0") ? RESOLVED_TYPE_IPV4 : RESOLVED_TYPE_IPV6);
-        const char *address = addressmap_register_virtual_address(
-                                                     type, tor_strdup(to));
-        if (!address) {
-          smartlist_add_asprintf(reply,
-                       "451-resource exhausted: skipping '%s'", line);
-          log_warn(LD_CONTROL,
-                   "Unable to allocate address for '%s' in MapAddress msg",
-                   safe_str_client(line));
-        } else {
-          smartlist_add_asprintf(reply, "250-%s=%s", address, to);
-        }
-      } else {
-        const char *msg;
-        if (addressmap_register_auto(from, to, 1,
-                                     ADDRMAPSRC_CONTROLLER, &msg) < 0) {
-          smartlist_add_asprintf(reply,
-                                 "512-syntax error: invalid address mapping "
-                                 " '%s': %s", line, msg);
-          log_warn(LD_CONTROL,
-                   "Skipping invalid argument '%s' in MapAddress msg: %s",
-                   line, msg);
-        } else {
-          smartlist_add_asprintf(reply, "250-%s", line);
-        }
-      }
-    } else {
-      smartlist_add_asprintf(reply, "512-syntax error: mapping '%s' is "
-                   "not of expected form 'foo=bar'.", line);
-      log_info(LD_CONTROL, "Skipping MapAddress '%s': wrong "
-                           "number of items.",
-                           safe_str_client(line));
-    }
-    SMARTLIST_FOREACH(elts, char *, cp, tor_free(cp));
-    smartlist_clear(elts);
-  } SMARTLIST_FOREACH_END(line);
-  SMARTLIST_FOREACH(lines, char *, cp, tor_free(cp));
-  smartlist_free(lines);
-  smartlist_free(elts);
-
-  if (smartlist_len(reply)) {
-    ((char*)smartlist_get(reply,smartlist_len(reply)-1))[3] = ' ';
-    r = smartlist_join_strings(reply, "\r\n", 1, &sz);
-    connection_buf_add(r, sz, TO_CONN(conn));
-    tor_free(r);
-  } else {
-    const char *response =
-      "512 syntax error: not enough arguments to mapaddress.\r\n";
-    connection_buf_add(response, strlen(response), TO_CONN(conn));
-  }
-
-  SMARTLIST_FOREACH(reply, char *, cp, tor_free(cp));
-  smartlist_free(reply);
-  return 0;
-}
-
-/** Implementation helper for GETINFO: knows the answers for various
- * trivial-to-implement questions. */
-static int
-getinfo_helper_misc(control_connection_t *conn, const char *question,
-                    char **answer, const char **errmsg)
-{
-  (void) conn;
-  if (!strcmp(question, "version")) {
-    *answer = tor_strdup(get_version());
-  } else if (!strcmp(question, "bw-event-cache")) {
-    *answer = get_bw_samples();
-  } else if (!strcmp(question, "config-file")) {
-    const char *a = get_torrc_fname(0);
-    if (a)
-      *answer = tor_strdup(a);
-  } else if (!strcmp(question, "config-defaults-file")) {
-    const char *a = get_torrc_fname(1);
-    if (a)
-      *answer = tor_strdup(a);
-  } else if (!strcmp(question, "config-text")) {
-    *answer = options_dump(get_options(), OPTIONS_DUMP_MINIMAL);
-  } else if (!strcmp(question, "config-can-saveconf")) {
-    *answer = tor_strdup(get_options()->IncludeUsed ? "0" : "1");
-  } else if (!strcmp(question, "info/names")) {
-    *answer = list_getinfo_options();
-  } else if (!strcmp(question, "dormant")) {
-    int dormant = rep_hist_circbuilding_dormant(time(NULL));
-    *answer = tor_strdup(dormant ? "1" : "0");
-  } else if (!strcmp(question, "events/names")) {
-    int i;
-    smartlist_t *event_names = smartlist_new();
-
-    for (i = 0; control_event_table[i].event_name != NULL; ++i) {
-      smartlist_add(event_names, (char *)control_event_table[i].event_name);
-    }
-
-    *answer = smartlist_join_strings(event_names, " ", 0, NULL);
-
-    smartlist_free(event_names);
-  } else if (!strcmp(question, "signal/names")) {
-    smartlist_t *signal_names = smartlist_new();
-    int j;
-    for (j = 0; signal_table[j].signal_name != NULL; ++j) {
-      smartlist_add(signal_names, (char*)signal_table[j].signal_name);
-    }
-
-    *answer = smartlist_join_strings(signal_names, " ", 0, NULL);
-
-    smartlist_free(signal_names);
-  } else if (!strcmp(question, "features/names")) {
-    *answer = tor_strdup("VERBOSE_NAMES EXTENDED_EVENTS");
-  } else if (!strcmp(question, "address")) {
-    uint32_t addr;
-    if (router_pick_published_address(get_options(), &addr, 0) < 0) {
-      *errmsg = "Address unknown";
-      return -1;
-    }
-    *answer = tor_dup_ip(addr);
-  } else if (!strcmp(question, "traffic/read")) {
-    tor_asprintf(answer, "%"PRIu64, (get_bytes_read()));
-  } else if (!strcmp(question, "traffic/written")) {
-    tor_asprintf(answer, "%"PRIu64, (get_bytes_written()));
-  } else if (!strcmp(question, "uptime")) {
-    long uptime_secs = get_uptime();
-    tor_asprintf(answer, "%ld", uptime_secs);
-  } else if (!strcmp(question, "process/pid")) {
-    int myPid = -1;
-
-#ifdef _WIN32
-      myPid = _getpid();
-#else
-      myPid = getpid();
-#endif
-
-    tor_asprintf(answer, "%d", myPid);
-  } else if (!strcmp(question, "process/uid")) {
-#ifdef _WIN32
-      *answer = tor_strdup("-1");
-#else
-      int myUid = geteuid();
-      tor_asprintf(answer, "%d", myUid);
-#endif /* defined(_WIN32) */
-  } else if (!strcmp(question, "process/user")) {
-#ifdef _WIN32
-      *answer = tor_strdup("");
-#else
-      int myUid = geteuid();
-      const struct passwd *myPwEntry = tor_getpwuid(myUid);
-
-      if (myPwEntry) {
-        *answer = tor_strdup(myPwEntry->pw_name);
-      } else {
-        *answer = tor_strdup("");
-      }
-#endif /* defined(_WIN32) */
-  } else if (!strcmp(question, "process/descriptor-limit")) {
-    int max_fds = get_max_sockets();
-    tor_asprintf(answer, "%d", max_fds);
-  } else if (!strcmp(question, "limits/max-mem-in-queues")) {
-    tor_asprintf(answer, "%"PRIu64,
-                 (get_options()->MaxMemInQueues));
-  } else if (!strcmp(question, "fingerprint")) {
-    crypto_pk_t *server_key;
-    if (!server_mode(get_options())) {
-      *errmsg = "Not running in server mode";
-      return -1;
-    }
-    server_key = get_server_identity_key();
-    *answer = tor_malloc(HEX_DIGEST_LEN+1);
-    crypto_pk_get_fingerprint(server_key, *answer, 0);
-  }
-  return 0;
-}
-
-/** Awful hack: return a newly allocated string based on a routerinfo and
- * (possibly) an extrainfo, sticking the read-history and write-history from
- * <b>ei</b> into the resulting string.  The thing you get back won't
- * necessarily have a valid signature.
- *
- * New code should never use this; it's for backward compatibility.
- *
- * NOTE: <b>ri_body</b> is as returned by signed_descriptor_get_body: it might
- * not be NUL-terminated. */
-static char *
-munge_extrainfo_into_routerinfo(const char *ri_body,
-                                const signed_descriptor_t *ri,
-                                const signed_descriptor_t *ei)
-{
-  char *out = NULL, *outp;
-  int i;
-  const char *router_sig;
-  const char *ei_body = signed_descriptor_get_body(ei);
-  size_t ri_len = ri->signed_descriptor_len;
-  size_t ei_len = ei->signed_descriptor_len;
-  if (!ei_body)
-    goto bail;
-
-  outp = out = tor_malloc(ri_len+ei_len+1);
-  if (!(router_sig = tor_memstr(ri_body, ri_len, "\nrouter-signature")))
-    goto bail;
-  ++router_sig;
-  memcpy(out, ri_body, router_sig-ri_body);
-  outp += router_sig-ri_body;
-
-  for (i=0; i < 2; ++i) {
-    const char *kwd = i ? "\nwrite-history " : "\nread-history ";
-    const char *cp, *eol;
-    if (!(cp = tor_memstr(ei_body, ei_len, kwd)))
-      continue;
-    ++cp;
-    if (!(eol = memchr(cp, '\n', ei_len - (cp-ei_body))))
-      continue;
-    memcpy(outp, cp, eol-cp+1);
-    outp += eol-cp+1;
-  }
-  memcpy(outp, router_sig, ri_len - (router_sig-ri_body));
-  *outp++ = '\0';
-  tor_assert(outp-out < (int)(ri_len+ei_len+1));
-
-  return out;
- bail:
-  tor_free(out);
-  return tor_strndup(ri_body, ri->signed_descriptor_len);
-}
-
-/** Implementation helper for GETINFO: answers requests for information about
- * which ports are bound. */
-static int
-getinfo_helper_listeners(control_connection_t *control_conn,
-                         const char *question,
-                         char **answer, const char **errmsg)
-{
-  int type;
-  smartlist_t *res;
-
-  (void)control_conn;
-  (void)errmsg;
-
-  if (!strcmp(question, "net/listeners/or"))
-    type = CONN_TYPE_OR_LISTENER;
-  else if (!strcmp(question, "net/listeners/extor"))
-    type = CONN_TYPE_EXT_OR_LISTENER;
-  else if (!strcmp(question, "net/listeners/dir"))
-    type = CONN_TYPE_DIR_LISTENER;
-  else if (!strcmp(question, "net/listeners/socks"))
-    type = CONN_TYPE_AP_LISTENER;
-  else if (!strcmp(question, "net/listeners/trans"))
-    type = CONN_TYPE_AP_TRANS_LISTENER;
-  else if (!strcmp(question, "net/listeners/natd"))
-    type = CONN_TYPE_AP_NATD_LISTENER;
-  else if (!strcmp(question, "net/listeners/httptunnel"))
-    type = CONN_TYPE_AP_HTTP_CONNECT_LISTENER;
-  else if (!strcmp(question, "net/listeners/dns"))
-    type = CONN_TYPE_AP_DNS_LISTENER;
-  else if (!strcmp(question, "net/listeners/control"))
-    type = CONN_TYPE_CONTROL_LISTENER;
-  else
-    return 0; /* unknown key */
-
-  res = smartlist_new();
-  SMARTLIST_FOREACH_BEGIN(get_connection_array(), connection_t *, conn) {
-    struct sockaddr_storage ss;
-    socklen_t ss_len = sizeof(ss);
-
-    if (conn->type != type || conn->marked_for_close || !SOCKET_OK(conn->s))
-      continue;
-
-    if (getsockname(conn->s, (struct sockaddr *)&ss, &ss_len) < 0) {
-      smartlist_add_asprintf(res, "%s:%d", conn->address, (int)conn->port);
-    } else {
-      char *tmp = tor_sockaddr_to_str((struct sockaddr *)&ss);
-      smartlist_add(res, esc_for_log(tmp));
-      tor_free(tmp);
-    }
-
-  } SMARTLIST_FOREACH_END(conn);
-
-  *answer = smartlist_join_strings(res, " ", 0, NULL);
-
-  SMARTLIST_FOREACH(res, char *, cp, tor_free(cp));
-  smartlist_free(res);
-  return 0;
-}
-
-/** Implementation helper for GETINFO: answers requests for information about
- * the current time in both local and UTC forms. */
-STATIC int
-getinfo_helper_current_time(control_connection_t *control_conn,
-                         const char *question,
-                         char **answer, const char **errmsg)
-{
-  (void)control_conn;
-  (void)errmsg;
-
-  struct timeval now;
-  tor_gettimeofday(&now);
-  char timebuf[ISO_TIME_LEN+1];
-
-  if (!strcmp(question, "current-time/local"))
-    format_local_iso_time_nospace(timebuf, (time_t)now.tv_sec);
-  else if (!strcmp(question, "current-time/utc"))
-    format_iso_time_nospace(timebuf, (time_t)now.tv_sec);
-  else
-    return 0;
-
-  *answer = tor_strdup(timebuf);
-  return 0;
-}
-
-/** Implementation helper for GETINFO: knows the answers for questions about
- * directory information. */
-STATIC int
-getinfo_helper_dir(control_connection_t *control_conn,
-                   const char *question, char **answer,
-                   const char **errmsg)
-{
-  (void) control_conn;
-  if (!strcmpstart(question, "desc/id/")) {
-    const routerinfo_t *ri = NULL;
-    const node_t *node = node_get_by_hex_id(question+strlen("desc/id/"), 0);
-    if (node)
-      ri = node->ri;
-    if (ri) {
-      const char *body = signed_descriptor_get_body(&ri->cache_info);
-      if (body)
-        *answer = tor_strndup(body, ri->cache_info.signed_descriptor_len);
-    } else if (! we_fetch_router_descriptors(get_options())) {
-      /* Descriptors won't be available, provide proper error */
-      *errmsg = "We fetch microdescriptors, not router "
-                "descriptors. You'll need to use md/id/* "
-                "instead of desc/id/*.";
-      return 0;
-    }
-  } else if (!strcmpstart(question, "desc/name/")) {
-    const routerinfo_t *ri = NULL;
-    /* XXX Setting 'warn_if_unnamed' here is a bit silly -- the
-     * warning goes to the user, not to the controller. */
-    const node_t *node =
-      node_get_by_nickname(question+strlen("desc/name/"), 0);
-    if (node)
-      ri = node->ri;
-    if (ri) {
-      const char *body = signed_descriptor_get_body(&ri->cache_info);
-      if (body)
-        *answer = tor_strndup(body, ri->cache_info.signed_descriptor_len);
-    } else if (! we_fetch_router_descriptors(get_options())) {
-      /* Descriptors won't be available, provide proper error */
-      *errmsg = "We fetch microdescriptors, not router "
-                "descriptors. You'll need to use md/name/* "
-                "instead of desc/name/*.";
-      return 0;
-    }
-  } else if (!strcmp(question, "desc/download-enabled")) {
-    int r = we_fetch_router_descriptors(get_options());
-    tor_asprintf(answer, "%d", !!r);
-  } else if (!strcmp(question, "desc/all-recent")) {
-    routerlist_t *routerlist = router_get_routerlist();
-    smartlist_t *sl = smartlist_new();
-    if (routerlist && routerlist->routers) {
-      SMARTLIST_FOREACH(routerlist->routers, const routerinfo_t *, ri,
-      {
-        const char *body = signed_descriptor_get_body(&ri->cache_info);
-        if (body)
-          smartlist_add(sl,
-                  tor_strndup(body, ri->cache_info.signed_descriptor_len));
-      });
-    }
-    *answer = smartlist_join_strings(sl, "", 0, NULL);
-    SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
-    smartlist_free(sl);
-  } else if (!strcmp(question, "desc/all-recent-extrainfo-hack")) {
-    /* XXXX Remove this once Torstat asks for extrainfos. */
-    routerlist_t *routerlist = router_get_routerlist();
-    smartlist_t *sl = smartlist_new();
-    if (routerlist && routerlist->routers) {
-      SMARTLIST_FOREACH_BEGIN(routerlist->routers, const routerinfo_t *, ri) {
-        const char *body = signed_descriptor_get_body(&ri->cache_info);
-        signed_descriptor_t *ei = extrainfo_get_by_descriptor_digest(
-                                     ri->cache_info.extra_info_digest);
-        if (ei && body) {
-          smartlist_add(sl, munge_extrainfo_into_routerinfo(body,
-                                                        &ri->cache_info, ei));
-        } else if (body) {
-          smartlist_add(sl,
-                  tor_strndup(body, ri->cache_info.signed_descriptor_len));
-        }
-      } SMARTLIST_FOREACH_END(ri);
-    }
-    *answer = smartlist_join_strings(sl, "", 0, NULL);
-    SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
-    smartlist_free(sl);
-  } else if (!strcmpstart(question, "hs/client/desc/id/")) {
-    hostname_type_t addr_type;
-
-    question += strlen("hs/client/desc/id/");
-    if (rend_valid_v2_service_id(question)) {
-      addr_type = ONION_V2_HOSTNAME;
-    } else if (hs_address_is_valid(question)) {
-      addr_type = ONION_V3_HOSTNAME;
-    } else {
-      *errmsg = "Invalid address";
-      return -1;
-    }
-
-    if (addr_type == ONION_V2_HOSTNAME) {
-      rend_cache_entry_t *e = NULL;
-      if (!rend_cache_lookup_entry(question, -1, &e)) {
-        /* Descriptor found in cache */
-        *answer = tor_strdup(e->desc);
-      } else {
-        *errmsg = "Not found in cache";
-        return -1;
-      }
-    } else {
-      ed25519_public_key_t service_pk;
-      const char *desc;
-
-      /* The check before this if/else makes sure of this. */
-      tor_assert(addr_type == ONION_V3_HOSTNAME);
-
-      if (hs_parse_address(question, &service_pk, NULL, NULL) < 0) {
-        *errmsg = "Invalid v3 address";
-        return -1;
-      }
-
-      desc = hs_cache_lookup_encoded_as_client(&service_pk);
-      if (desc) {
-        *answer = tor_strdup(desc);
-      } else {
-        *errmsg = "Not found in cache";
-        return -1;
-      }
-    }
-  } else if (!strcmpstart(question, "hs/service/desc/id/")) {
-    hostname_type_t addr_type;
-
-    question += strlen("hs/service/desc/id/");
-    if (rend_valid_v2_service_id(question)) {
-      addr_type = ONION_V2_HOSTNAME;
-    } else if (hs_address_is_valid(question)) {
-      addr_type = ONION_V3_HOSTNAME;
-    } else {
-      *errmsg = "Invalid address";
-      return -1;
-    }
-    rend_cache_entry_t *e = NULL;
-
-    if (addr_type == ONION_V2_HOSTNAME) {
-      if (!rend_cache_lookup_v2_desc_as_service(question, &e)) {
-        /* Descriptor found in cache */
-        *answer = tor_strdup(e->desc);
-      } else {
-        *errmsg = "Not found in cache";
-        return -1;
-      }
-    } else {
-      ed25519_public_key_t service_pk;
-      char *desc;
-
-      /* The check before this if/else makes sure of this. */
-      tor_assert(addr_type == ONION_V3_HOSTNAME);
-
-      if (hs_parse_address(question, &service_pk, NULL, NULL) < 0) {
-        *errmsg = "Invalid v3 address";
-        return -1;
-      }
-
-      desc = hs_service_lookup_current_desc(&service_pk);
-      if (desc) {
-        /* Newly allocated string, we have ownership. */
-        *answer = desc;
-      } else {
-        *errmsg = "Not found in cache";
-        return -1;
-      }
-    }
-  } else if (!strcmp(question, "md/all")) {
-    const smartlist_t *nodes = nodelist_get_list();
-    tor_assert(nodes);
-
-    if (smartlist_len(nodes) == 0) {
-      *answer = tor_strdup("");
-      return 0;
-    }
-
-    smartlist_t *microdescs = smartlist_new();
-
-    SMARTLIST_FOREACH_BEGIN(nodes, node_t *, n) {
-      if (n->md && n->md->body) {
-        char *copy = tor_strndup(n->md->body, n->md->bodylen);
-        smartlist_add(microdescs, copy);
-      }
-    } SMARTLIST_FOREACH_END(n);
-
-    *answer = smartlist_join_strings(microdescs, "", 0, NULL);
-    SMARTLIST_FOREACH(microdescs, char *, md, tor_free(md));
-    smartlist_free(microdescs);
-  } else if (!strcmpstart(question, "md/id/")) {
-    const node_t *node = node_get_by_hex_id(question+strlen("md/id/"), 0);
-    const microdesc_t *md = NULL;
-    if (node) md = node->md;
-    if (md && md->body) {
-      *answer = tor_strndup(md->body, md->bodylen);
-    }
-  } else if (!strcmpstart(question, "md/name/")) {
-    /* XXX Setting 'warn_if_unnamed' here is a bit silly -- the
-     * warning goes to the user, not to the controller. */
-    const node_t *node = node_get_by_nickname(question+strlen("md/name/"), 0);
-    /* XXXX duplicated code */
-    const microdesc_t *md = NULL;
-    if (node) md = node->md;
-    if (md && md->body) {
-      *answer = tor_strndup(md->body, md->bodylen);
-    }
-  } else if (!strcmp(question, "md/download-enabled")) {
-    int r = we_fetch_microdescriptors(get_options());
-    tor_asprintf(answer, "%d", !!r);
-  } else if (!strcmpstart(question, "desc-annotations/id/")) {
-    const routerinfo_t *ri = NULL;
-    const node_t *node =
-      node_get_by_hex_id(question+strlen("desc-annotations/id/"), 0);
-    if (node)
-      ri = node->ri;
-    if (ri) {
-      const char *annotations =
-        signed_descriptor_get_annotations(&ri->cache_info);
-      if (annotations)
-        *answer = tor_strndup(annotations,
-                              ri->cache_info.annotations_len);
-    }
-  } else if (!strcmpstart(question, "dir/server/")) {
-    size_t answer_len = 0;
-    char *url = NULL;
-    smartlist_t *descs = smartlist_new();
-    const char *msg;
-    int res;
-    char *cp;
-    tor_asprintf(&url, "/tor/%s", question+4);
-    res = dirserv_get_routerdescs(descs, url, &msg);
-    if (res) {
-      log_warn(LD_CONTROL, "getinfo '%s': %s", question, msg);
-      smartlist_free(descs);
-      tor_free(url);
-      *errmsg = msg;
-      return -1;
-    }
-    SMARTLIST_FOREACH(descs, signed_descriptor_t *, sd,
-                      answer_len += sd->signed_descriptor_len);
-    cp = *answer = tor_malloc(answer_len+1);
-    SMARTLIST_FOREACH(descs, signed_descriptor_t *, sd,
-                      {
-                        memcpy(cp, signed_descriptor_get_body(sd),
-                               sd->signed_descriptor_len);
-                        cp += sd->signed_descriptor_len;
-                      });
-    *cp = '\0';
-    tor_free(url);
-    smartlist_free(descs);
-  } else if (!strcmpstart(question, "dir/status/")) {
-    *answer = tor_strdup("");
-  } else if (!strcmp(question, "dir/status-vote/current/consensus")) { /* v3 */
-    if (we_want_to_fetch_flavor(get_options(), FLAV_NS)) {
-      const cached_dir_t *consensus = dirserv_get_consensus("ns");
-      if (consensus)
-        *answer = tor_strdup(consensus->dir);
-    }
-    if (!*answer) { /* try loading it from disk */
-      tor_mmap_t *mapped = networkstatus_map_cached_consensus("ns");
-      if (mapped) {
-        *answer = tor_memdup_nulterm(mapped->data, mapped->size);
-        tor_munmap_file(mapped);
-      }
-      if (!*answer) { /* generate an error */
-        *errmsg = "Could not open cached consensus. "
-          "Make sure FetchUselessDescriptors is set to 1.";
-        return -1;
-      }
-    }
-  } else if (!strcmp(question, "network-status")) { /* v1 */
-    static int network_status_warned = 0;
-    if (!network_status_warned) {
-      log_warn(LD_CONTROL, "GETINFO network-status is deprecated; it will "
-               "go away in a future version of Tor.");
-      network_status_warned = 1;
-    }
-    routerlist_t *routerlist = router_get_routerlist();
-    if (!routerlist || !routerlist->routers ||
-        list_server_status_v1(routerlist->routers, answer, 1) < 0) {
-      return -1;
-    }
-  } else if (!strcmpstart(question, "extra-info/digest/")) {
-    question += strlen("extra-info/digest/");
-    if (strlen(question) == HEX_DIGEST_LEN) {
-      char d[DIGEST_LEN];
-      signed_descriptor_t *sd = NULL;
-      if (base16_decode(d, sizeof(d), question, strlen(question))
-                        == sizeof(d)) {
-        /* XXXX this test should move into extrainfo_get_by_descriptor_digest,
-         * but I don't want to risk affecting other parts of the code,
-         * especially since the rules for using our own extrainfo (including
-         * when it might be freed) are different from those for using one
-         * we have downloaded. */
-        if (router_extrainfo_digest_is_me(d))
-          sd = &(router_get_my_extrainfo()->cache_info);
-        else
-          sd = extrainfo_get_by_descriptor_digest(d);
-      }
-      if (sd) {
-        const char *body = signed_descriptor_get_body(sd);
-        if (body)
-          *answer = tor_strndup(body, sd->signed_descriptor_len);
-      }
-    }
-  }
-
-  return 0;
-}
-
-/** Given a smartlist of 20-byte digests, return a newly allocated string
- * containing each of those digests in order, formatted in HEX, and terminated
- * with a newline. */
-static char *
-digest_list_to_string(const smartlist_t *sl)
-{
-  int len;
-  char *result, *s;
-
-  /* Allow for newlines, and a \0 at the end */
-  len = smartlist_len(sl) * (HEX_DIGEST_LEN + 1) + 1;
-  result = tor_malloc_zero(len);
-
-  s = result;
-  SMARTLIST_FOREACH_BEGIN(sl, const char *, digest) {
-    base16_encode(s, HEX_DIGEST_LEN + 1, digest, DIGEST_LEN);
-    s[HEX_DIGEST_LEN] = '\n';
-    s += HEX_DIGEST_LEN + 1;
-  } SMARTLIST_FOREACH_END(digest);
-  *s = '\0';
-
-  return result;
-}
-
-/** Turn a download_status_t into a human-readable description in a newly
- * allocated string.  The format is specified in control-spec.txt, under
- * the documentation for "GETINFO download/..." .  */
-static char *
-download_status_to_string(const download_status_t *dl)
-{
-  char *rv = NULL;
-  char tbuf[ISO_TIME_LEN+1];
-  const char *schedule_str, *want_authority_str;
-  const char *increment_on_str, *backoff_str;
-
-  if (dl) {
-    /* Get some substrings of the eventual output ready */
-    format_iso_time(tbuf, download_status_get_next_attempt_at(dl));
-
-    switch (dl->schedule) {
-      case DL_SCHED_GENERIC:
-        schedule_str = "DL_SCHED_GENERIC";
-        break;
-      case DL_SCHED_CONSENSUS:
-        schedule_str = "DL_SCHED_CONSENSUS";
-        break;
-      case DL_SCHED_BRIDGE:
-        schedule_str = "DL_SCHED_BRIDGE";
-        break;
-      default:
-        schedule_str = "unknown";
-        break;
-    }
-
-    switch (dl->want_authority) {
-      case DL_WANT_ANY_DIRSERVER:
-        want_authority_str = "DL_WANT_ANY_DIRSERVER";
-        break;
-      case DL_WANT_AUTHORITY:
-        want_authority_str = "DL_WANT_AUTHORITY";
-        break;
-      default:
-        want_authority_str = "unknown";
-        break;
-    }
-
-    switch (dl->increment_on) {
-      case DL_SCHED_INCREMENT_FAILURE:
-        increment_on_str = "DL_SCHED_INCREMENT_FAILURE";
-        break;
-      case DL_SCHED_INCREMENT_ATTEMPT:
-        increment_on_str = "DL_SCHED_INCREMENT_ATTEMPT";
-        break;
-      default:
-        increment_on_str = "unknown";
-        break;
-    }
-
-    backoff_str = "DL_SCHED_RANDOM_EXPONENTIAL";
-
-    /* Now assemble them */
-    tor_asprintf(&rv,
-                 "next-attempt-at %s\n"
-                 "n-download-failures %u\n"
-                 "n-download-attempts %u\n"
-                 "schedule %s\n"
-                 "want-authority %s\n"
-                 "increment-on %s\n"
-                 "backoff %s\n"
-                 "last-backoff-position %u\n"
-                 "last-delay-used %d\n",
-                 tbuf,
-                 dl->n_download_failures,
-                 dl->n_download_attempts,
-                 schedule_str,
-                 want_authority_str,
-                 increment_on_str,
-                 backoff_str,
-                 dl->last_backoff_position,
-                 dl->last_delay_used);
-  }
-
-  return rv;
-}
-
-/** Handle the consensus download cases for getinfo_helper_downloads() */
-STATIC void
-getinfo_helper_downloads_networkstatus(const char *flavor,
-                                       download_status_t **dl_to_emit,
-                                       const char **errmsg)
-{
-  /*
-   * We get the one for the current bootstrapped status by default, or
-   * take an extra /bootstrap or /running suffix
-   */
-  if (strcmp(flavor, "ns") == 0) {
-    *dl_to_emit = networkstatus_get_dl_status_by_flavor(FLAV_NS);
-  } else if (strcmp(flavor, "ns/bootstrap") == 0) {
-    *dl_to_emit = networkstatus_get_dl_status_by_flavor_bootstrap(FLAV_NS);
-  } else if (strcmp(flavor, "ns/running") == 0 ) {
-    *dl_to_emit = networkstatus_get_dl_status_by_flavor_running(FLAV_NS);
-  } else if (strcmp(flavor, "microdesc") == 0) {
-    *dl_to_emit = networkstatus_get_dl_status_by_flavor(FLAV_MICRODESC);
-  } else if (strcmp(flavor, "microdesc/bootstrap") == 0) {
-    *dl_to_emit =
-      networkstatus_get_dl_status_by_flavor_bootstrap(FLAV_MICRODESC);
-  } else if (strcmp(flavor, "microdesc/running") == 0) {
-    *dl_to_emit =
-      networkstatus_get_dl_status_by_flavor_running(FLAV_MICRODESC);
-  } else {
-    *errmsg = "Unknown flavor";
-  }
-}
-
-/** Handle the cert download cases for getinfo_helper_downloads() */
-STATIC void
-getinfo_helper_downloads_cert(const char *fp_sk_req,
-                              download_status_t **dl_to_emit,
-                              smartlist_t **digest_list,
-                              const char **errmsg)
-{
-  const char *sk_req;
-  char id_digest[DIGEST_LEN];
-  char sk_digest[DIGEST_LEN];
-
-  /*
-   * We have to handle four cases; fp_sk_req is the request with
-   * a prefix of "downloads/cert/" snipped off.
-   *
-   * Case 1: fp_sk_req = "fps"
-   *  - We should emit a digest_list with a list of all the identity
-   *    fingerprints that can be queried for certificate download status;
-   *    get it by calling list_authority_ids_with_downloads().
-   *
-   * Case 2: fp_sk_req = "fp/<fp>" for some fingerprint fp
-   *  - We want the default certificate for this identity fingerprint's
-   *    download status; this is the download we get from URLs starting
-   *    in /fp/ on the directory server.  We can get it with
-   *    id_only_download_status_for_authority_id().
-   *
-   * Case 3: fp_sk_req = "fp/<fp>/sks" for some fingerprint fp
-   *  - We want a list of all signing key digests for this identity
-   *    fingerprint which can be queried for certificate download status.
-   *    Get it with list_sk_digests_for_authority_id().
-   *
-   * Case 4: fp_sk_req = "fp/<fp>/<sk>" for some fingerprint fp and
-   *         signing key digest sk
-   *   - We want the download status for the certificate for this specific
-   *     signing key and fingerprint.  These correspond to the ones we get
-   *     from URLs starting in /fp-sk/ on the directory server.  Get it with
-   *     list_sk_digests_for_authority_id().
-   */
-
-  if (strcmp(fp_sk_req, "fps") == 0) {
-    *digest_list = list_authority_ids_with_downloads();
-    if (!(*digest_list)) {
-      *errmsg = "Failed to get list of authority identity digests (!)";
-    }
-  } else if (!strcmpstart(fp_sk_req, "fp/")) {
-    fp_sk_req += strlen("fp/");
-    /* Okay, look for another / to tell the fp from fp-sk cases */
-    sk_req = strchr(fp_sk_req, '/');
-    if (sk_req) {
-      /* okay, split it here and try to parse <fp> */
-      if (base16_decode(id_digest, DIGEST_LEN,
-                        fp_sk_req, sk_req - fp_sk_req) == DIGEST_LEN) {
-        /* Skip past the '/' */
-        ++sk_req;
-        if (strcmp(sk_req, "sks") == 0) {
-          /* We're asking for the list of signing key fingerprints */
-          *digest_list = list_sk_digests_for_authority_id(id_digest);
-          if (!(*digest_list)) {
-            *errmsg = "Failed to get list of signing key digests for this "
-                      "authority identity digest";
-          }
-        } else {
-          /* We've got a signing key digest */
-          if (base16_decode(sk_digest, DIGEST_LEN,
-                            sk_req, strlen(sk_req)) == DIGEST_LEN) {
-            *dl_to_emit =
-              download_status_for_authority_id_and_sk(id_digest, sk_digest);
-            if (!(*dl_to_emit)) {
-              *errmsg = "Failed to get download status for this identity/"
-                        "signing key digest pair";
-            }
-          } else {
-            *errmsg = "That didn't look like a signing key digest";
-          }
-        }
-      } else {
-        *errmsg = "That didn't look like an identity digest";
-      }
-    } else {
-      /* We're either in downloads/certs/fp/<fp>, or we can't parse <fp> */
-      if (strlen(fp_sk_req) == HEX_DIGEST_LEN) {
-        if (base16_decode(id_digest, DIGEST_LEN,
-                          fp_sk_req, strlen(fp_sk_req)) == DIGEST_LEN) {
-          *dl_to_emit = id_only_download_status_for_authority_id(id_digest);
-          if (!(*dl_to_emit)) {
-            *errmsg = "Failed to get download status for this authority "
-                      "identity digest";
-          }
-        } else {
-          *errmsg = "That didn't look like a digest";
-        }
-      } else {
-        *errmsg = "That didn't look like a digest";
-      }
-    }
-  } else {
-    *errmsg = "Unknown certificate download status query";
-  }
-}
-
-/** Handle the routerdesc download cases for getinfo_helper_downloads() */
-STATIC void
-getinfo_helper_downloads_desc(const char *desc_req,
-                              download_status_t **dl_to_emit,
-                              smartlist_t **digest_list,
-                              const char **errmsg)
-{
-  char desc_digest[DIGEST_LEN];
-  /*
-   * Two cases to handle here:
-   *
-   * Case 1: desc_req = "descs"
-   *   - Emit a list of all router descriptor digests, which we get by
-   *     calling router_get_descriptor_digests(); this can return NULL
-   *     if we have no current ns-flavor consensus.
-   *
-   * Case 2: desc_req = <fp>
-   *   - Check on the specified fingerprint and emit its download_status_t
-   *     using router_get_dl_status_by_descriptor_digest().
-   */
-
-  if (strcmp(desc_req, "descs") == 0) {
-    *digest_list = router_get_descriptor_digests();
-    if (!(*digest_list)) {
-      *errmsg = "We don't seem to have a networkstatus-flavored consensus";
-    }
-    /*
-     * Microdescs don't use the download_status_t mechanism, so we don't
-     * answer queries about their downloads here; see microdesc.c.
-     */
-  } else if (strlen(desc_req) == HEX_DIGEST_LEN) {
-    if (base16_decode(desc_digest, DIGEST_LEN,
-                      desc_req, strlen(desc_req)) == DIGEST_LEN) {
-      /* Okay we got a digest-shaped thing; try asking for it */
-      *dl_to_emit = router_get_dl_status_by_descriptor_digest(desc_digest);
-      if (!(*dl_to_emit)) {
-        *errmsg = "No such descriptor digest found";
-      }
-    } else {
-      *errmsg = "That didn't look like a digest";
-    }
-  } else {
-    *errmsg = "Unknown router descriptor download status query";
-  }
-}
-
-/** Handle the bridge download cases for getinfo_helper_downloads() */
-STATIC void
-getinfo_helper_downloads_bridge(const char *bridge_req,
-                                download_status_t **dl_to_emit,
-                                smartlist_t **digest_list,
-                                const char **errmsg)
-{
-  char bridge_digest[DIGEST_LEN];
-  /*
-   * Two cases to handle here:
-   *
-   * Case 1: bridge_req = "bridges"
-   *   - Emit a list of all bridge identity digests, which we get by
-   *     calling list_bridge_identities(); this can return NULL if we are
-   *     not using bridges.
-   *
-   * Case 2: bridge_req = <fp>
-   *   - Check on the specified fingerprint and emit its download_status_t
-   *     using get_bridge_dl_status_by_id().
-   */
-
-  if (strcmp(bridge_req, "bridges") == 0) {
-    *digest_list = list_bridge_identities();
-    if (!(*digest_list)) {
-      *errmsg = "We don't seem to be using bridges";
-    }
-  } else if (strlen(bridge_req) == HEX_DIGEST_LEN) {
-    if (base16_decode(bridge_digest, DIGEST_LEN,
-                      bridge_req, strlen(bridge_req)) == DIGEST_LEN) {
-      /* Okay we got a digest-shaped thing; try asking for it */
-      *dl_to_emit = get_bridge_dl_status_by_id(bridge_digest);
-      if (!(*dl_to_emit)) {
-        *errmsg = "No such bridge identity digest found";
-      }
-    } else {
-      *errmsg = "That didn't look like a digest";
-    }
-  } else {
-    *errmsg = "Unknown bridge descriptor download status query";
-  }
-}
-
-/** Implementation helper for GETINFO: knows the answers for questions about
- * download status information. */
-STATIC int
-getinfo_helper_downloads(control_connection_t *control_conn,
-                   const char *question, char **answer,
-                   const char **errmsg)
-{
-  download_status_t *dl_to_emit = NULL;
-  smartlist_t *digest_list = NULL;
-
-  /* Assert args are sane */
-  tor_assert(control_conn != NULL);
-  tor_assert(question != NULL);
-  tor_assert(answer != NULL);
-  tor_assert(errmsg != NULL);
-
-  /* We check for this later to see if we should supply a default */
-  *errmsg = NULL;
-
-  /* Are we after networkstatus downloads? */
-  if (!strcmpstart(question, "downloads/networkstatus/")) {
-    getinfo_helper_downloads_networkstatus(
-        question + strlen("downloads/networkstatus/"),
-        &dl_to_emit, errmsg);
-  /* Certificates? */
-  } else if (!strcmpstart(question, "downloads/cert/")) {
-    getinfo_helper_downloads_cert(
-        question + strlen("downloads/cert/"),
-        &dl_to_emit, &digest_list, errmsg);
-  /* Router descriptors? */
-  } else if (!strcmpstart(question, "downloads/desc/")) {
-    getinfo_helper_downloads_desc(
-        question + strlen("downloads/desc/"),
-        &dl_to_emit, &digest_list, errmsg);
-  /* Bridge descriptors? */
-  } else if (!strcmpstart(question, "downloads/bridge/")) {
-    getinfo_helper_downloads_bridge(
-        question + strlen("downloads/bridge/"),
-        &dl_to_emit, &digest_list, errmsg);
-  } else {
-    *errmsg = "Unknown download status query";
-  }
-
-  if (dl_to_emit) {
-    *answer = download_status_to_string(dl_to_emit);
-
-    return 0;
-  } else if (digest_list) {
-    *answer = digest_list_to_string(digest_list);
-    SMARTLIST_FOREACH(digest_list, void *, s, tor_free(s));
-    smartlist_free(digest_list);
-
-    return 0;
-  } else {
-    if (!(*errmsg)) {
-      *errmsg = "Unknown error";
-    }
-
-    return -1;
-  }
-}
-
-/** Allocate and return a description of <b>circ</b>'s current status,
- * including its path (if any). */
-static char *
-circuit_describe_status_for_controller(origin_circuit_t *circ)
-{
-  char *rv;
-  smartlist_t *descparts = smartlist_new();
-
-  {
-    char *vpath = circuit_list_path_for_controller(circ);
-    if (*vpath) {
-      smartlist_add(descparts, vpath);
-    } else {
-      tor_free(vpath); /* empty path; don't put an extra space in the result */
-    }
-  }
-
-  {
-    cpath_build_state_t *build_state = circ->build_state;
-    smartlist_t *flaglist = smartlist_new();
-    char *flaglist_joined;
-
-    if (build_state->onehop_tunnel)
-      smartlist_add(flaglist, (void *)"ONEHOP_TUNNEL");
-    if (build_state->is_internal)
-      smartlist_add(flaglist, (void *)"IS_INTERNAL");
-    if (build_state->need_capacity)
-      smartlist_add(flaglist, (void *)"NEED_CAPACITY");
-    if (build_state->need_uptime)
-      smartlist_add(flaglist, (void *)"NEED_UPTIME");
-
-    /* Only emit a BUILD_FLAGS argument if it will have a non-empty value. */
-    if (smartlist_len(flaglist)) {
-      flaglist_joined = smartlist_join_strings(flaglist, ",", 0, NULL);
-
-      smartlist_add_asprintf(descparts, "BUILD_FLAGS=%s", flaglist_joined);
-
-      tor_free(flaglist_joined);
-    }
-
-    smartlist_free(flaglist);
-  }
-
-  smartlist_add_asprintf(descparts, "PURPOSE=%s",
-                    circuit_purpose_to_controller_string(circ->base_.purpose));
-
-  {
-    const char *hs_state =
-      circuit_purpose_to_controller_hs_state_string(circ->base_.purpose);
-
-    if (hs_state != NULL) {
-      smartlist_add_asprintf(descparts, "HS_STATE=%s", hs_state);
-    }
-  }
-
-  if (circ->rend_data != NULL || circ->hs_ident != NULL) {
-    char addr[HS_SERVICE_ADDR_LEN_BASE32 + 1];
-    const char *onion_address;
-    if (circ->rend_data) {
-      onion_address = rend_data_get_address(circ->rend_data);
-    } else {
-      hs_build_address(&circ->hs_ident->identity_pk, HS_VERSION_THREE, addr);
-      onion_address = addr;
-    }
-    smartlist_add_asprintf(descparts, "REND_QUERY=%s", onion_address);
-  }
-
-  {
-    char tbuf[ISO_TIME_USEC_LEN+1];
-    format_iso_time_nospace_usec(tbuf, &circ->base_.timestamp_created);
-
-    smartlist_add_asprintf(descparts, "TIME_CREATED=%s", tbuf);
-  }
-
-  // Show username and/or password if available.
-  if (circ->socks_username_len > 0) {
-    char* socks_username_escaped = esc_for_log_len(circ->socks_username,
-                                     (size_t) circ->socks_username_len);
-    smartlist_add_asprintf(descparts, "SOCKS_USERNAME=%s",
-                           socks_username_escaped);
-    tor_free(socks_username_escaped);
-  }
-  if (circ->socks_password_len > 0) {
-    char* socks_password_escaped = esc_for_log_len(circ->socks_password,
-                                     (size_t) circ->socks_password_len);
-    smartlist_add_asprintf(descparts, "SOCKS_PASSWORD=%s",
-                           socks_password_escaped);
-    tor_free(socks_password_escaped);
-  }
-
-  rv = smartlist_join_strings(descparts, " ", 0, NULL);
-
-  SMARTLIST_FOREACH(descparts, char *, cp, tor_free(cp));
-  smartlist_free(descparts);
-
-  return rv;
-}
-
-/** Implementation helper for GETINFO: knows how to generate summaries of the
- * current states of things we send events about. */
-static int
-getinfo_helper_events(control_connection_t *control_conn,
-                      const char *question, char **answer,
-                      const char **errmsg)
-{
-  const or_options_t *options = get_options();
-  (void) control_conn;
-  if (!strcmp(question, "circuit-status")) {
-    smartlist_t *status = smartlist_new();
-    SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ_) {
-      origin_circuit_t *circ;
-      char *circdesc;
-      const char *state;
-      if (! CIRCUIT_IS_ORIGIN(circ_) || circ_->marked_for_close)
-        continue;
-      circ = TO_ORIGIN_CIRCUIT(circ_);
-
-      if (circ->base_.state == CIRCUIT_STATE_OPEN)
-        state = "BUILT";
-      else if (circ->base_.state == CIRCUIT_STATE_GUARD_WAIT)
-        state = "GUARD_WAIT";
-      else if (circ->cpath)
-        state = "EXTENDED";
-      else
-        state = "LAUNCHED";
-
-      circdesc = circuit_describe_status_for_controller(circ);
-
-      smartlist_add_asprintf(status, "%lu %s%s%s",
-                   (unsigned long)circ->global_identifier,
-                   state, *circdesc ? " " : "", circdesc);
-      tor_free(circdesc);
-    }
-    SMARTLIST_FOREACH_END(circ_);
-    *answer = smartlist_join_strings(status, "\r\n", 0, NULL);
-    SMARTLIST_FOREACH(status, char *, cp, tor_free(cp));
-    smartlist_free(status);
-  } else if (!strcmp(question, "stream-status")) {
-    smartlist_t *conns = get_connection_array();
-    smartlist_t *status = smartlist_new();
-    char buf[256];
-    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
-      const char *state;
-      entry_connection_t *conn;
-      circuit_t *circ;
-      origin_circuit_t *origin_circ = NULL;
-      if (base_conn->type != CONN_TYPE_AP ||
-          base_conn->marked_for_close ||
-          base_conn->state == AP_CONN_STATE_SOCKS_WAIT ||
-          base_conn->state == AP_CONN_STATE_NATD_WAIT)
-        continue;
-      conn = TO_ENTRY_CONN(base_conn);
-      switch (base_conn->state)
-        {
-        case AP_CONN_STATE_CONTROLLER_WAIT:
-        case AP_CONN_STATE_CIRCUIT_WAIT:
-          if (conn->socks_request &&
-              SOCKS_COMMAND_IS_RESOLVE(conn->socks_request->command))
-            state = "NEWRESOLVE";
-          else
-            state = "NEW";
-          break;
-        case AP_CONN_STATE_RENDDESC_WAIT:
-        case AP_CONN_STATE_CONNECT_WAIT:
-          state = "SENTCONNECT"; break;
-        case AP_CONN_STATE_RESOLVE_WAIT:
-          state = "SENTRESOLVE"; break;
-        case AP_CONN_STATE_OPEN:
-          state = "SUCCEEDED"; break;
-        default:
-          log_warn(LD_BUG, "Asked for stream in unknown state %d",
-                   base_conn->state);
-          continue;
-        }
-      circ = circuit_get_by_edge_conn(ENTRY_TO_EDGE_CONN(conn));
-      if (circ && CIRCUIT_IS_ORIGIN(circ))
-        origin_circ = TO_ORIGIN_CIRCUIT(circ);
-      write_stream_target_to_buf(conn, buf, sizeof(buf));
-      smartlist_add_asprintf(status, "%lu %s %lu %s",
-                   (unsigned long) base_conn->global_identifier,state,
-                   origin_circ?
-                         (unsigned long)origin_circ->global_identifier : 0ul,
-                   buf);
-    } SMARTLIST_FOREACH_END(base_conn);
-    *answer = smartlist_join_strings(status, "\r\n", 0, NULL);
-    SMARTLIST_FOREACH(status, char *, cp, tor_free(cp));
-    smartlist_free(status);
-  } else if (!strcmp(question, "orconn-status")) {
-    smartlist_t *conns = get_connection_array();
-    smartlist_t *status = smartlist_new();
-    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
-      const char *state;
-      char name[128];
-      or_connection_t *conn;
-      if (base_conn->type != CONN_TYPE_OR || base_conn->marked_for_close)
-        continue;
-      conn = TO_OR_CONN(base_conn);
-      if (conn->base_.state == OR_CONN_STATE_OPEN)
-        state = "CONNECTED";
-      else if (conn->nickname)
-        state = "LAUNCHED";
-      else
-        state = "NEW";
-      orconn_target_get_name(name, sizeof(name), conn);
-      smartlist_add_asprintf(status, "%s %s", name, state);
-    } SMARTLIST_FOREACH_END(base_conn);
-    *answer = smartlist_join_strings(status, "\r\n", 0, NULL);
-    SMARTLIST_FOREACH(status, char *, cp, tor_free(cp));
-    smartlist_free(status);
-  } else if (!strcmpstart(question, "address-mappings/")) {
-    time_t min_e, max_e;
-    smartlist_t *mappings;
-    question += strlen("address-mappings/");
-    if (!strcmp(question, "all")) {
-      min_e = 0; max_e = TIME_MAX;
-    } else if (!strcmp(question, "cache")) {
-      min_e = 2; max_e = TIME_MAX;
-    } else if (!strcmp(question, "config")) {
-      min_e = 0; max_e = 0;
-    } else if (!strcmp(question, "control")) {
-      min_e = 1; max_e = 1;
-    } else {
-      return 0;
-    }
-    mappings = smartlist_new();
-    addressmap_get_mappings(mappings, min_e, max_e, 1);
-    *answer = smartlist_join_strings(mappings, "\r\n", 0, NULL);
-    SMARTLIST_FOREACH(mappings, char *, cp, tor_free(cp));
-    smartlist_free(mappings);
-  } else if (!strcmpstart(question, "status/")) {
-    /* Note that status/ is not a catch-all for events; there's only supposed
-     * to be a status GETINFO if there's a corresponding STATUS event. */
-    if (!strcmp(question, "status/circuit-established")) {
-      *answer = tor_strdup(have_completed_a_circuit() ? "1" : "0");
-    } else if (!strcmp(question, "status/enough-dir-info")) {
-      *answer = tor_strdup(router_have_minimum_dir_info() ? "1" : "0");
-    } else if (!strcmp(question, "status/good-server-descriptor") ||
-               !strcmp(question, "status/accepted-server-descriptor")) {
-      /* They're equivalent for now, until we can figure out how to make
-       * good-server-descriptor be what we want. See comment in
-       * control-spec.txt. */
-      *answer = tor_strdup(directories_have_accepted_server_descriptor()
-                           ? "1" : "0");
-    } else if (!strcmp(question, "status/reachability-succeeded/or")) {
-      *answer = tor_strdup(check_whether_orport_reachable(options) ?
-                            "1" : "0");
-    } else if (!strcmp(question, "status/reachability-succeeded/dir")) {
-      *answer = tor_strdup(check_whether_dirport_reachable(options) ?
-                            "1" : "0");
-    } else if (!strcmp(question, "status/reachability-succeeded")) {
-      tor_asprintf(answer, "OR=%d DIR=%d",
-                   check_whether_orport_reachable(options) ? 1 : 0,
-                   check_whether_dirport_reachable(options) ? 1 : 0);
-    } else if (!strcmp(question, "status/bootstrap-phase")) {
-      *answer = control_event_boot_last_msg();
-    } else if (!strcmpstart(question, "status/version/")) {
-      int is_server = server_mode(options);
-      networkstatus_t *c = networkstatus_get_latest_consensus();
-      version_status_t status;
-      const char *recommended;
-      if (c) {
-        recommended = is_server ? c->server_versions : c->client_versions;
-        status = tor_version_is_obsolete(VERSION, recommended);
-      } else {
-        recommended = "?";
-        status = VS_UNKNOWN;
-      }
-
-      if (!strcmp(question, "status/version/recommended")) {
-        *answer = tor_strdup(recommended);
-        return 0;
-      }
-      if (!strcmp(question, "status/version/current")) {
-        switch (status)
-          {
-          case VS_RECOMMENDED: *answer = tor_strdup("recommended"); break;
-          case VS_OLD: *answer = tor_strdup("obsolete"); break;
-          case VS_NEW: *answer = tor_strdup("new"); break;
-          case VS_NEW_IN_SERIES: *answer = tor_strdup("new in series"); break;
-          case VS_UNRECOMMENDED: *answer = tor_strdup("unrecommended"); break;
-          case VS_EMPTY: *answer = tor_strdup("none recommended"); break;
-          case VS_UNKNOWN: *answer = tor_strdup("unknown"); break;
-          default: tor_fragile_assert();
-          }
-      }
-    } else if (!strcmp(question, "status/clients-seen")) {
-      char *bridge_stats = geoip_get_bridge_stats_controller(time(NULL));
-      if (!bridge_stats) {
-        *errmsg = "No bridge-client stats available";
-        return -1;
-      }
-      *answer = bridge_stats;
-    } else if (!strcmp(question, "status/fresh-relay-descs")) {
-      if (!server_mode(options)) {
-        *errmsg = "Only relays have descriptors";
-        return -1;
-      }
-      routerinfo_t *r;
-      extrainfo_t *e;
-      if (router_build_fresh_descriptor(&r, &e) < 0) {
-        *errmsg = "Error generating descriptor";
-        return -1;
-      }
-      size_t size = r->cache_info.signed_descriptor_len + 1;
-      if (e) {
-        size += e->cache_info.signed_descriptor_len + 1;
-      }
-      tor_assert(r->cache_info.signed_descriptor_len);
-      char *descs = tor_malloc(size);
-      char *cp = descs;
-      memcpy(cp, signed_descriptor_get_body(&r->cache_info),
-             r->cache_info.signed_descriptor_len);
-      cp += r->cache_info.signed_descriptor_len - 1;
-      if (e) {
-        if (cp[0] == '\0') {
-          cp[0] = '\n';
-        } else if (cp[0] != '\n') {
-          cp[1] = '\n';
-          cp++;
-        }
-        memcpy(cp, signed_descriptor_get_body(&e->cache_info),
-               e->cache_info.signed_descriptor_len);
-        cp += e->cache_info.signed_descriptor_len - 1;
-      }
-      if (cp[0] == '\n') {
-        cp[0] = '\0';
-      } else if (cp[0] != '\0') {
-        cp[1] = '\0';
-      }
-      *answer = descs;
-      routerinfo_free(r);
-      extrainfo_free(e);
-    } else {
-      return 0;
-    }
-  }
-  return 0;
-}
-
-/** Implementation helper for GETINFO: knows how to enumerate hidden services
- * created via the control port. */
-STATIC int
-getinfo_helper_onions(control_connection_t *control_conn,
-                      const char *question, char **answer,
-                      const char **errmsg)
-{
-  smartlist_t *onion_list = NULL;
-  (void) errmsg;  /* no errors from this method */
-
-  if (control_conn && !strcmp(question, "onions/current")) {
-    onion_list = control_conn->ephemeral_onion_services;
-  } else if (!strcmp(question, "onions/detached")) {
-    onion_list = detached_onion_services;
-  } else {
-    return 0;
-  }
-  if (!onion_list || smartlist_len(onion_list) == 0) {
-    if (answer) {
-      *answer = tor_strdup("");
-    }
-  } else {
-    if (answer) {
-      *answer = smartlist_join_strings(onion_list, "\r\n", 0, NULL);
-    }
-  }
-
-  return 0;
-}
-
-/** Implementation helper for GETINFO: answers queries about network
- * liveness. */
-static int
-getinfo_helper_liveness(control_connection_t *control_conn,
-                      const char *question, char **answer,
-                      const char **errmsg)
-{
-  (void)control_conn;
-  (void)errmsg;
-  if (strcmp(question, "network-liveness") == 0) {
-    if (get_cached_network_liveness()) {
-      *answer = tor_strdup("up");
-    } else {
-      *answer = tor_strdup("down");
-    }
-  }
-
-  return 0;
-}
-
-/** Implementation helper for GETINFO: answers queries about shared random
- * value. */
-static int
-getinfo_helper_sr(control_connection_t *control_conn,
-                  const char *question, char **answer,
-                  const char **errmsg)
-{
-  (void) control_conn;
-  (void) errmsg;
-
-  if (!strcmp(question, "sr/current")) {
-    *answer = sr_get_current_for_control();
-  } else if (!strcmp(question, "sr/previous")) {
-    *answer = sr_get_previous_for_control();
-  }
-  /* Else statement here is unrecognized key so do nothing. */
-
-  return 0;
-}
-
-/** Callback function for GETINFO: on a given control connection, try to
- * answer the question <b>q</b> and store the newly-allocated answer in
- * *<b>a</b>. If an internal error occurs, return -1 and optionally set
- * *<b>error_out</b> to point to an error message to be delivered to the
- * controller. On success, _or if the key is not recognized_, return 0. Do not
- * set <b>a</b> if the key is not recognized but you may set <b>error_out</b>
- * to improve the error message.
- */
-typedef int (*getinfo_helper_t)(control_connection_t *,
-                                const char *q, char **a,
-                                const char **error_out);
-
-/** A single item for the GETINFO question-to-answer-function table. */
-typedef struct getinfo_item_t {
-  const char *varname; /**< The value (or prefix) of the question. */
-  getinfo_helper_t fn; /**< The function that knows the answer: NULL if
-                        * this entry is documentation-only. */
-  const char *desc; /**< Description of the variable. */
-  int is_prefix; /** Must varname match exactly, or must it be a prefix? */
-} getinfo_item_t;
-
-#define ITEM(name, fn, desc) { name, getinfo_helper_##fn, desc, 0 }
-#define PREFIX(name, fn, desc) { name, getinfo_helper_##fn, desc, 1 }
-#define DOC(name, desc) { name, NULL, desc, 0 }
-
-/** Table mapping questions accepted by GETINFO to the functions that know how
- * to answer them. */
-static const getinfo_item_t getinfo_items[] = {
-  ITEM("version", misc, "The current version of Tor."),
-  ITEM("bw-event-cache", misc, "Cached BW events for a short interval."),
-  ITEM("config-file", misc, "Current location of the \"torrc\" file."),
-  ITEM("config-defaults-file", misc, "Current location of the defaults file."),
-  ITEM("config-text", misc,
-       "Return the string that would be written by a saveconf command."),
-  ITEM("config-can-saveconf", misc,
-       "Is it possible to save the configuration to the \"torrc\" file?"),
-  ITEM("accounting/bytes", accounting,
-       "Number of bytes read/written so far in the accounting interval."),
-  ITEM("accounting/bytes-left", accounting,
-      "Number of bytes left to write/read so far in the accounting interval."),
-  ITEM("accounting/enabled", accounting, "Is accounting currently enabled?"),
-  ITEM("accounting/hibernating", accounting, "Are we hibernating or awake?"),
-  ITEM("accounting/interval-start", accounting,
-       "Time when the accounting period starts."),
-  ITEM("accounting/interval-end", accounting,
-       "Time when the accounting period ends."),
-  ITEM("accounting/interval-wake", accounting,
-       "Time to wake up in this accounting period."),
-  ITEM("helper-nodes", entry_guards, NULL), /* deprecated */
-  ITEM("entry-guards", entry_guards,
-       "Which nodes are we using as entry guards?"),
-  ITEM("fingerprint", misc, NULL),
-  PREFIX("config/", config, "Current configuration values."),
-  DOC("config/names",
-      "List of configuration options, types, and documentation."),
-  DOC("config/defaults",
-      "List of default values for configuration options. "
-      "See also config/names"),
-  PREFIX("current-time/", current_time, "Current time."),
-  DOC("current-time/local", "Current time on the local system."),
-  DOC("current-time/utc", "Current UTC time."),
-  PREFIX("downloads/networkstatus/", downloads,
-         "Download statuses for networkstatus objects"),
-  DOC("downloads/networkstatus/ns",
-      "Download status for current-mode networkstatus download"),
-  DOC("downloads/networkstatus/ns/bootstrap",
-      "Download status for bootstrap-time networkstatus download"),
-  DOC("downloads/networkstatus/ns/running",
-      "Download status for run-time networkstatus download"),
-  DOC("downloads/networkstatus/microdesc",
-      "Download status for current-mode microdesc download"),
-  DOC("downloads/networkstatus/microdesc/bootstrap",
-      "Download status for bootstrap-time microdesc download"),
-  DOC("downloads/networkstatus/microdesc/running",
-      "Download status for run-time microdesc download"),
-  PREFIX("downloads/cert/", downloads,
-         "Download statuses for certificates, by id fingerprint and "
-         "signing key"),
-  DOC("downloads/cert/fps",
-      "List of authority fingerprints for which any download statuses "
-      "exist"),
-  DOC("downloads/cert/fp/<fp>",
-      "Download status for <fp> with the default signing key; corresponds "
-      "to /fp/ URLs on directory server."),
-  DOC("downloads/cert/fp/<fp>/sks",
-      "List of signing keys for which specific download statuses are "
-      "available for this id fingerprint"),
-  DOC("downloads/cert/fp/<fp>/<sk>",
-      "Download status for <fp> with signing key <sk>; corresponds "
-      "to /fp-sk/ URLs on directory server."),
-  PREFIX("downloads/desc/", downloads,
-         "Download statuses for router descriptors, by descriptor digest"),
-  DOC("downloads/desc/descs",
-      "Return a list of known router descriptor digests"),
-  DOC("downloads/desc/<desc>",
-      "Return a download status for a given descriptor digest"),
-  PREFIX("downloads/bridge/", downloads,
-         "Download statuses for bridge descriptors, by bridge identity "
-         "digest"),
-  DOC("downloads/bridge/bridges",
-      "Return a list of configured bridge identity digests with download "
-      "statuses"),
-  DOC("downloads/bridge/<desc>",
-      "Return a download status for a given bridge identity digest"),
-  ITEM("info/names", misc,
-       "List of GETINFO options, types, and documentation."),
-  ITEM("events/names", misc,
-       "Events that the controller can ask for with SETEVENTS."),
-  ITEM("signal/names", misc, "Signal names recognized by the SIGNAL command"),
-  ITEM("features/names", misc, "What arguments can USEFEATURE take?"),
-  PREFIX("desc/id/", dir, "Router descriptors by ID."),
-  PREFIX("desc/name/", dir, "Router descriptors by nickname."),
-  ITEM("desc/all-recent", dir,
-       "All non-expired, non-superseded router descriptors."),
-  ITEM("desc/download-enabled", dir,
-       "Do we try to download router descriptors?"),
-  ITEM("desc/all-recent-extrainfo-hack", dir, NULL), /* Hack. */
-  ITEM("md/all", dir, "All known microdescriptors."),
-  PREFIX("md/id/", dir, "Microdescriptors by ID"),
-  PREFIX("md/name/", dir, "Microdescriptors by name"),
-  ITEM("md/download-enabled", dir,
-       "Do we try to download microdescriptors?"),
-  PREFIX("extra-info/digest/", dir, "Extra-info documents by digest."),
-  PREFIX("hs/client/desc/id", dir,
-         "Hidden Service descriptor in client's cache by onion."),
-  PREFIX("hs/service/desc/id/", dir,
-         "Hidden Service descriptor in services's cache by onion."),
-  PREFIX("net/listeners/", listeners, "Bound addresses by type"),
-  ITEM("ns/all", networkstatus,
-       "Brief summary of router status (v2 directory format)"),
-  PREFIX("ns/id/", networkstatus,
-         "Brief summary of router status by ID (v2 directory format)."),
-  PREFIX("ns/name/", networkstatus,
-         "Brief summary of router status by nickname (v2 directory format)."),
-  PREFIX("ns/purpose/", networkstatus,
-         "Brief summary of router status by purpose (v2 directory format)."),
-  PREFIX("consensus/", networkstatus,
-         "Information about and from the ns consensus."),
-  ITEM("network-status", dir,
-       "Brief summary of router status (v1 directory format)"),
-  ITEM("network-liveness", liveness,
-       "Current opinion on whether the network is live"),
-  ITEM("circuit-status", events, "List of current circuits originating here."),
-  ITEM("stream-status", events,"List of current streams."),
-  ITEM("orconn-status", events, "A list of current OR connections."),
-  ITEM("dormant", misc,
-       "Is Tor dormant (not building circuits because it's idle)?"),
-  PREFIX("address-mappings/", events, NULL),
-  DOC("address-mappings/all", "Current address mappings."),
-  DOC("address-mappings/cache", "Current cached DNS replies."),
-  DOC("address-mappings/config",
-      "Current address mappings from configuration."),
-  DOC("address-mappings/control", "Current address mappings from controller."),
-  PREFIX("status/", events, NULL),
-  DOC("status/circuit-established",
-      "Whether we think client functionality is working."),
-  DOC("status/enough-dir-info",
-      "Whether we have enough up-to-date directory information to build "
-      "circuits."),
-  DOC("status/bootstrap-phase",
-      "The last bootstrap phase status event that Tor sent."),
-  DOC("status/clients-seen",
-      "Breakdown of client countries seen by a bridge."),
-  DOC("status/fresh-relay-descs",
-      "A fresh relay/ei descriptor pair for Tor's current state. Not stored."),
-  DOC("status/version/recommended", "List of currently recommended versions."),
-  DOC("status/version/current", "Status of the current version."),
-  ITEM("address", misc, "IP address of this Tor host, if we can guess it."),
-  ITEM("traffic/read", misc,"Bytes read since the process was started."),
-  ITEM("traffic/written", misc,
-       "Bytes written since the process was started."),
-  ITEM("uptime", misc, "Uptime of the Tor daemon in seconds."),
-  ITEM("process/pid", misc, "Process id belonging to the main tor process."),
-  ITEM("process/uid", misc, "User id running the tor process."),
-  ITEM("process/user", misc,
-       "Username under which the tor process is running."),
-  ITEM("process/descriptor-limit", misc, "File descriptor limit."),
-  ITEM("limits/max-mem-in-queues", misc, "Actual limit on memory in queues"),
-  PREFIX("desc-annotations/id/", dir, "Router annotations by hexdigest."),
-  PREFIX("dir/server/", dir,"Router descriptors as retrieved from a DirPort."),
-  PREFIX("dir/status/", dir,
-         "v2 networkstatus docs as retrieved from a DirPort."),
-  ITEM("dir/status-vote/current/consensus", dir,
-       "v3 Networkstatus consensus as retrieved from a DirPort."),
-  ITEM("exit-policy/default", policies,
-       "The default value appended to the configured exit policy."),
-  ITEM("exit-policy/reject-private/default", policies,
-       "The default rules appended to the configured exit policy by"
-       " ExitPolicyRejectPrivate."),
-  ITEM("exit-policy/reject-private/relay", policies,
-       "The relay-specific rules appended to the configured exit policy by"
-       " ExitPolicyRejectPrivate and/or ExitPolicyRejectLocalInterfaces."),
-  ITEM("exit-policy/full", policies, "The entire exit policy of onion router"),
-  ITEM("exit-policy/ipv4", policies, "IPv4 parts of exit policy"),
-  ITEM("exit-policy/ipv6", policies, "IPv6 parts of exit policy"),
-  PREFIX("ip-to-country/", geoip, "Perform a GEOIP lookup"),
-  ITEM("onions/current", onions,
-       "Onion services owned by the current control connection."),
-  ITEM("onions/detached", onions,
-       "Onion services detached from the control connection."),
-  ITEM("sr/current", sr, "Get current shared random value."),
-  ITEM("sr/previous", sr, "Get previous shared random value."),
-  { NULL, NULL, NULL, 0 }
-};
-
-/** Allocate and return a list of recognized GETINFO options. */
-static char *
-list_getinfo_options(void)
-{
-  int i;
-  smartlist_t *lines = smartlist_new();
-  char *ans;
-  for (i = 0; getinfo_items[i].varname; ++i) {
-    if (!getinfo_items[i].desc)
-      continue;
-
-    smartlist_add_asprintf(lines, "%s%s -- %s\n",
-                 getinfo_items[i].varname,
-                 getinfo_items[i].is_prefix ? "*" : "",
-                 getinfo_items[i].desc);
-  }
-  smartlist_sort_strings(lines);
-
-  ans = smartlist_join_strings(lines, "", 0, NULL);
-  SMARTLIST_FOREACH(lines, char *, cp, tor_free(cp));
-  smartlist_free(lines);
-
-  return ans;
-}
-
-/** Lookup the 'getinfo' entry <b>question</b>, and return
- * the answer in <b>*answer</b> (or NULL if key not recognized).
- * Return 0 if success or unrecognized, or -1 if recognized but
- * internal error. */
-static int
-handle_getinfo_helper(control_connection_t *control_conn,
-                      const char *question, char **answer,
-                      const char **err_out)
-{
-  int i;
-  *answer = NULL; /* unrecognized key by default */
-
-  for (i = 0; getinfo_items[i].varname; ++i) {
-    int match;
-    if (getinfo_items[i].is_prefix)
-      match = !strcmpstart(question, getinfo_items[i].varname);
-    else
-      match = !strcmp(question, getinfo_items[i].varname);
-    if (match) {
-      tor_assert(getinfo_items[i].fn);
-      return getinfo_items[i].fn(control_conn, question, answer, err_out);
-    }
-  }
-
-  return 0; /* unrecognized */
-}
-
-/** Called when we receive a GETINFO command.  Try to fetch all requested
- * information, and reply with information or error message. */
-static int
-handle_control_getinfo(control_connection_t *conn, uint32_t len,
-                       const char *body)
-{
-  smartlist_t *questions = smartlist_new();
-  smartlist_t *answers = smartlist_new();
-  smartlist_t *unrecognized = smartlist_new();
-  char *ans = NULL;
-  int i;
-  (void) len; /* body is NUL-terminated, so it's safe to ignore the length. */
-
-  smartlist_split_string(questions, body, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-  SMARTLIST_FOREACH_BEGIN(questions, const char *, q) {
-    const char *errmsg = NULL;
-
-    if (handle_getinfo_helper(conn, q, &ans, &errmsg) < 0) {
-      if (!errmsg)
-        errmsg = "Internal error";
-      connection_printf_to_buf(conn, "551 %s\r\n", errmsg);
-      goto done;
-    }
-    if (!ans) {
-      if (errmsg) /* use provided error message */
-        smartlist_add_strdup(unrecognized, errmsg);
-      else /* use default error message */
-        smartlist_add_asprintf(unrecognized, "Unrecognized key \"%s\"", q);
-    } else {
-      smartlist_add_strdup(answers, q);
-      smartlist_add(answers, ans);
-    }
-  } SMARTLIST_FOREACH_END(q);
-
-  if (smartlist_len(unrecognized)) {
-    /* control-spec section 2.3, mid-reply '-' or end of reply ' ' */
-    for (i=0; i < smartlist_len(unrecognized)-1; ++i)
-      connection_printf_to_buf(conn,
-                               "552-%s\r\n",
-                               (char *)smartlist_get(unrecognized, i));
-
-    connection_printf_to_buf(conn,
-                             "552 %s\r\n",
-                             (char *)smartlist_get(unrecognized, i));
-    goto done;
-  }
-
-  for (i = 0; i < smartlist_len(answers); i += 2) {
-    char *k = smartlist_get(answers, i);
-    char *v = smartlist_get(answers, i+1);
-    if (!strchr(v, '\n') && !strchr(v, '\r')) {
-      connection_printf_to_buf(conn, "250-%s=", k);
-      connection_write_str_to_buf(v, conn);
-      connection_write_str_to_buf("\r\n", conn);
-    } else {
-      char *esc = NULL;
-      size_t esc_len;
-      esc_len = write_escaped_data(v, strlen(v), &esc);
-      connection_printf_to_buf(conn, "250+%s=\r\n", k);
-      connection_buf_add(esc, esc_len, TO_CONN(conn));
-      tor_free(esc);
-    }
-  }
-  connection_write_str_to_buf("250 OK\r\n", conn);
-
- done:
-  SMARTLIST_FOREACH(answers, char *, cp, tor_free(cp));
-  smartlist_free(answers);
-  SMARTLIST_FOREACH(questions, char *, cp, tor_free(cp));
-  smartlist_free(questions);
-  SMARTLIST_FOREACH(unrecognized, char *, cp, tor_free(cp));
-  smartlist_free(unrecognized);
-
-  return 0;
-}
-
-/** Given a string, convert it to a circuit purpose. */
-static uint8_t
-circuit_purpose_from_string(const char *string)
-{
-  if (!strcasecmpstart(string, "purpose="))
-    string += strlen("purpose=");
-
-  if (!strcasecmp(string, "general"))
-    return CIRCUIT_PURPOSE_C_GENERAL;
-  else if (!strcasecmp(string, "controller"))
-    return CIRCUIT_PURPOSE_CONTROLLER;
-  else
-    return CIRCUIT_PURPOSE_UNKNOWN;
-}
-
-/** Return a newly allocated smartlist containing the arguments to the command
- * waiting in <b>body</b>. If there are fewer than <b>min_args</b> arguments,
- * or if <b>max_args</b> is nonnegative and there are more than
- * <b>max_args</b> arguments, send a 512 error to the controller, using
- * <b>command</b> as the command name in the error message. */
-static smartlist_t *
-getargs_helper(const char *command, control_connection_t *conn,
-               const char *body, int min_args, int max_args)
-{
-  smartlist_t *args = smartlist_new();
-  smartlist_split_string(args, body, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-  if (smartlist_len(args) < min_args) {
-    connection_printf_to_buf(conn, "512 Missing argument to %s\r\n",command);
-    goto err;
-  } else if (max_args >= 0 && smartlist_len(args) > max_args) {
-    connection_printf_to_buf(conn, "512 Too many arguments to %s\r\n",command);
-    goto err;
-  }
-  return args;
- err:
-  SMARTLIST_FOREACH(args, char *, s, tor_free(s));
-  smartlist_free(args);
-  return NULL;
-}
-
-/** Helper.  Return the first element of <b>sl</b> at index <b>start_at</b> or
- * higher that starts with <b>prefix</b>, case-insensitive.  Return NULL if no
- * such element exists. */
-static const char *
-find_element_starting_with(smartlist_t *sl, int start_at, const char *prefix)
-{
-  int i;
-  for (i = start_at; i < smartlist_len(sl); ++i) {
-    const char *elt = smartlist_get(sl, i);
-    if (!strcasecmpstart(elt, prefix))
-      return elt;
-  }
-  return NULL;
-}
-
-/** Helper.  Return true iff s is an argument that we should treat as a
- * key-value pair. */
-static int
-is_keyval_pair(const char *s)
-{
-  /* An argument is a key-value pair if it has an =, and it isn't of the form
-   * $fingeprint=name */
-  return strchr(s, '=') && s[0] != '$';
-}
-
-/** Called when we get an EXTENDCIRCUIT message.  Try to extend the listed
- * circuit, and report success or failure. */
-static int
-handle_control_extendcircuit(control_connection_t *conn, uint32_t len,
-                             const char *body)
-{
-  smartlist_t *router_nicknames=NULL, *nodes=NULL;
-  origin_circuit_t *circ = NULL;
-  int zero_circ;
-  uint8_t intended_purpose = CIRCUIT_PURPOSE_C_GENERAL;
-  smartlist_t *args;
-  (void) len;
-
-  router_nicknames = smartlist_new();
-
-  args = getargs_helper("EXTENDCIRCUIT", conn, body, 1, -1);
-  if (!args)
-    goto done;
-
-  zero_circ = !strcmp("0", (char*)smartlist_get(args,0));
-
-  if (zero_circ) {
-    const char *purp = find_element_starting_with(args, 1, "PURPOSE=");
-
-    if (purp) {
-      intended_purpose = circuit_purpose_from_string(purp);
-      if (intended_purpose == CIRCUIT_PURPOSE_UNKNOWN) {
-        connection_printf_to_buf(conn, "552 Unknown purpose \"%s\"\r\n", purp);
-        SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-        smartlist_free(args);
-        goto done;
-      }
-    }
-
-    if ((smartlist_len(args) == 1) ||
-        (smartlist_len(args) >= 2 && is_keyval_pair(smartlist_get(args, 1)))) {
-      // "EXTENDCIRCUIT 0" || EXTENDCIRCUIT 0 foo=bar"
-      circ = circuit_launch(intended_purpose, CIRCLAUNCH_NEED_CAPACITY);
-      if (!circ) {
-        connection_write_str_to_buf("551 Couldn't start circuit\r\n", conn);
-      } else {
-        connection_printf_to_buf(conn, "250 EXTENDED %lu\r\n",
-                  (unsigned long)circ->global_identifier);
-      }
-      SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-      smartlist_free(args);
-      goto done;
-    }
-    // "EXTENDCIRCUIT 0 router1,router2" ||
-    // "EXTENDCIRCUIT 0 router1,router2 PURPOSE=foo"
-  }
-
-  if (!zero_circ && !(circ = get_circ(smartlist_get(args,0)))) {
-    connection_printf_to_buf(conn, "552 Unknown circuit \"%s\"\r\n",
-                             (char*)smartlist_get(args, 0));
-    SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-    smartlist_free(args);
-    goto done;
-  }
-
-  if (smartlist_len(args) < 2) {
-    connection_printf_to_buf(conn,
-                             "512 syntax error: not enough arguments.\r\n");
-    SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-    smartlist_free(args);
-    goto done;
-  }
-
-  smartlist_split_string(router_nicknames, smartlist_get(args,1), ",", 0, 0);
-
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-
-  nodes = smartlist_new();
-  int first_node = zero_circ;
-  SMARTLIST_FOREACH_BEGIN(router_nicknames, const char *, n) {
-    const node_t *node = node_get_by_nickname(n, 0);
-    if (!node) {
-      connection_printf_to_buf(conn, "552 No such router \"%s\"\r\n", n);
-      goto done;
-    }
-    if (!node_has_preferred_descriptor(node, first_node)) {
-      connection_printf_to_buf(conn, "552 No descriptor for \"%s\"\r\n", n);
-      goto done;
-    }
-    smartlist_add(nodes, (void*)node);
-    first_node = 0;
-  } SMARTLIST_FOREACH_END(n);
-  if (!smartlist_len(nodes)) {
-    connection_write_str_to_buf("512 No router names provided\r\n", conn);
-    goto done;
-  }
-
-  if (zero_circ) {
-    /* start a new circuit */
-    circ = origin_circuit_init(intended_purpose, 0);
-  }
-
-  /* now circ refers to something that is ready to be extended */
-  first_node = zero_circ;
-  SMARTLIST_FOREACH(nodes, const node_t *, node,
-  {
-    extend_info_t *info = extend_info_from_node(node, first_node);
-    if (!info) {
-      tor_assert_nonfatal(first_node);
-      log_warn(LD_CONTROL,
-               "controller tried to connect to a node that lacks a suitable "
-               "descriptor, or which doesn't have any "
-               "addresses that are allowed by the firewall configuration; "
-               "circuit marked for closing.");
-      circuit_mark_for_close(TO_CIRCUIT(circ), -END_CIRC_REASON_CONNECTFAILED);
-      connection_write_str_to_buf("551 Couldn't start circuit\r\n", conn);
-      goto done;
-    }
-    circuit_append_new_exit(circ, info);
-    if (circ->build_state->desired_path_len > 1) {
-      circ->build_state->onehop_tunnel = 0;
-    }
-    extend_info_free(info);
-    first_node = 0;
-  });
-
-  /* now that we've populated the cpath, start extending */
-  if (zero_circ) {
-    int err_reason = 0;
-    if ((err_reason = circuit_handle_first_hop(circ)) < 0) {
-      circuit_mark_for_close(TO_CIRCUIT(circ), -err_reason);
-      connection_write_str_to_buf("551 Couldn't start circuit\r\n", conn);
-      goto done;
-    }
-  } else {
-    if (circ->base_.state == CIRCUIT_STATE_OPEN ||
-        circ->base_.state == CIRCUIT_STATE_GUARD_WAIT) {
-      int err_reason = 0;
-      circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_BUILDING);
-      if ((err_reason = circuit_send_next_onion_skin(circ)) < 0) {
-        log_info(LD_CONTROL,
-                 "send_next_onion_skin failed; circuit marked for closing.");
-        circuit_mark_for_close(TO_CIRCUIT(circ), -err_reason);
-        connection_write_str_to_buf("551 Couldn't send onion skin\r\n", conn);
-        goto done;
-      }
-    }
-  }
-
-  connection_printf_to_buf(conn, "250 EXTENDED %lu\r\n",
-                             (unsigned long)circ->global_identifier);
-  if (zero_circ) /* send a 'launched' event, for completeness */
-    circuit_event_status(circ, CIRC_EVENT_LAUNCHED, 0);
- done:
-  SMARTLIST_FOREACH(router_nicknames, char *, n, tor_free(n));
-  smartlist_free(router_nicknames);
-  smartlist_free(nodes);
-  return 0;
-}
-
-/** Called when we get a SETCIRCUITPURPOSE message. If we can find the
- * circuit and it's a valid purpose, change it. */
-static int
-handle_control_setcircuitpurpose(control_connection_t *conn,
-                                 uint32_t len, const char *body)
-{
-  origin_circuit_t *circ = NULL;
-  uint8_t new_purpose;
-  smartlist_t *args;
-  (void) len; /* body is NUL-terminated, so it's safe to ignore the length. */
-
-  args = getargs_helper("SETCIRCUITPURPOSE", conn, body, 2, -1);
-  if (!args)
-    goto done;
-
-  if (!(circ = get_circ(smartlist_get(args,0)))) {
-    connection_printf_to_buf(conn, "552 Unknown circuit \"%s\"\r\n",
-                             (char*)smartlist_get(args, 0));
-    goto done;
-  }
-
-  {
-    const char *purp = find_element_starting_with(args,1,"PURPOSE=");
-    if (!purp) {
-      connection_write_str_to_buf("552 No purpose given\r\n", conn);
-      goto done;
-    }
-    new_purpose = circuit_purpose_from_string(purp);
-    if (new_purpose == CIRCUIT_PURPOSE_UNKNOWN) {
-      connection_printf_to_buf(conn, "552 Unknown purpose \"%s\"\r\n", purp);
-      goto done;
-    }
-  }
-
-  circuit_change_purpose(TO_CIRCUIT(circ), new_purpose);
-  connection_write_str_to_buf("250 OK\r\n", conn);
-
- done:
-  if (args) {
-    SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-    smartlist_free(args);
-  }
-  return 0;
-}
-
-/** Called when we get an ATTACHSTREAM message.  Try to attach the requested
- * stream, and report success or failure. */
-static int
-handle_control_attachstream(control_connection_t *conn, uint32_t len,
-                            const char *body)
-{
-  entry_connection_t *ap_conn = NULL;
-  origin_circuit_t *circ = NULL;
-  int zero_circ;
-  smartlist_t *args;
-  crypt_path_t *cpath=NULL;
-  int hop=0, hop_line_ok=1;
-  (void) len;
-
-  args = getargs_helper("ATTACHSTREAM", conn, body, 2, -1);
-  if (!args)
-    return 0;
-
-  zero_circ = !strcmp("0", (char*)smartlist_get(args,1));
-
-  if (!(ap_conn = get_stream(smartlist_get(args, 0)))) {
-    connection_printf_to_buf(conn, "552 Unknown stream \"%s\"\r\n",
-                             (char*)smartlist_get(args, 0));
-  } else if (!zero_circ && !(circ = get_circ(smartlist_get(args, 1)))) {
-    connection_printf_to_buf(conn, "552 Unknown circuit \"%s\"\r\n",
-                             (char*)smartlist_get(args, 1));
-  } else if (circ) {
-    const char *hopstring = find_element_starting_with(args,2,"HOP=");
-    if (hopstring) {
-      hopstring += strlen("HOP=");
-      hop = (int) tor_parse_ulong(hopstring, 10, 0, INT_MAX,
-                                  &hop_line_ok, NULL);
-      if (!hop_line_ok) { /* broken hop line */
-        connection_printf_to_buf(conn, "552 Bad value hop=%s\r\n", hopstring);
-      }
-    }
-  }
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-  if (!ap_conn || (!zero_circ && !circ) || !hop_line_ok)
-    return 0;
-
-  if (ENTRY_TO_CONN(ap_conn)->state != AP_CONN_STATE_CONTROLLER_WAIT &&
-      ENTRY_TO_CONN(ap_conn)->state != AP_CONN_STATE_CONNECT_WAIT &&
-      ENTRY_TO_CONN(ap_conn)->state != AP_CONN_STATE_RESOLVE_WAIT) {
-    connection_write_str_to_buf(
-                    "555 Connection is not managed by controller.\r\n",
-                    conn);
-    return 0;
-  }
-
-  /* Do we need to detach it first? */
-  if (ENTRY_TO_CONN(ap_conn)->state != AP_CONN_STATE_CONTROLLER_WAIT) {
-    edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(ap_conn);
-    circuit_t *tmpcirc = circuit_get_by_edge_conn(edge_conn);
-    connection_edge_end(edge_conn, END_STREAM_REASON_TIMEOUT);
-    /* Un-mark it as ending, since we're going to reuse it. */
-    edge_conn->edge_has_sent_end = 0;
-    edge_conn->end_reason = 0;
-    if (tmpcirc)
-      circuit_detach_stream(tmpcirc, edge_conn);
-    CONNECTION_AP_EXPECT_NONPENDING(ap_conn);
-    TO_CONN(edge_conn)->state = AP_CONN_STATE_CONTROLLER_WAIT;
-  }
-
-  if (circ && (circ->base_.state != CIRCUIT_STATE_OPEN)) {
-    connection_write_str_to_buf(
-                    "551 Can't attach stream to non-open origin circuit\r\n",
-                    conn);
-    return 0;
-  }
-  /* Is this a single hop circuit? */
-  if (circ && (circuit_get_cpath_len(circ)<2 || hop==1)) {
-    connection_write_str_to_buf(
-               "551 Can't attach stream to this one-hop circuit.\r\n", conn);
-    return 0;
-  }
-
-  if (circ && hop>0) {
-    /* find this hop in the circuit, and set cpath */
-    cpath = circuit_get_cpath_hop(circ, hop);
-    if (!cpath) {
-      connection_printf_to_buf(conn,
-                               "551 Circuit doesn't have %d hops.\r\n", hop);
-      return 0;
-    }
-  }
-  if (connection_ap_handshake_rewrite_and_attach(ap_conn, circ, cpath) < 0) {
-    connection_write_str_to_buf("551 Unable to attach stream\r\n", conn);
-    return 0;
-  }
-  send_control_done(conn);
-  return 0;
-}
-
-/** Called when we get a POSTDESCRIPTOR message.  Try to learn the provided
- * descriptor, and report success or failure. */
-static int
-handle_control_postdescriptor(control_connection_t *conn, uint32_t len,
-                              const char *body)
-{
-  char *desc;
-  const char *msg=NULL;
-  uint8_t purpose = ROUTER_PURPOSE_GENERAL;
-  int cache = 0; /* eventually, we may switch this to 1 */
-
-  const char *cp = memchr(body, '\n', len);
-
-  if (cp == NULL) {
-    connection_printf_to_buf(conn, "251 Empty body\r\n");
-    return 0;
-  }
-  ++cp;
-
-  char *cmdline = tor_memdup_nulterm(body, cp-body);
-  smartlist_t *args = smartlist_new();
-  smartlist_split_string(args, cmdline, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-  SMARTLIST_FOREACH_BEGIN(args, char *, option) {
-    if (!strcasecmpstart(option, "purpose=")) {
-      option += strlen("purpose=");
-      purpose = router_purpose_from_string(option);
-      if (purpose == ROUTER_PURPOSE_UNKNOWN) {
-        connection_printf_to_buf(conn, "552 Unknown purpose \"%s\"\r\n",
-                                 option);
-        goto done;
-      }
-    } else if (!strcasecmpstart(option, "cache=")) {
-      option += strlen("cache=");
-      if (!strcasecmp(option, "no"))
-        cache = 0;
-      else if (!strcasecmp(option, "yes"))
-        cache = 1;
-      else {
-        connection_printf_to_buf(conn, "552 Unknown cache request \"%s\"\r\n",
-                                 option);
-        goto done;
-      }
-    } else { /* unrecognized argument? */
-      connection_printf_to_buf(conn,
-        "512 Unexpected argument \"%s\" to postdescriptor\r\n", option);
-      goto done;
-    }
-  } SMARTLIST_FOREACH_END(option);
-
-  read_escaped_data(cp, len-(cp-body), &desc);
-
-  switch (router_load_single_router(desc, purpose, cache, &msg)) {
-  case -1:
-    if (!msg) msg = "Could not parse descriptor";
-    connection_printf_to_buf(conn, "554 %s\r\n", msg);
-    break;
-  case 0:
-    if (!msg) msg = "Descriptor not added";
-    connection_printf_to_buf(conn, "251 %s\r\n",msg);
-    break;
-  case 1:
-    send_control_done(conn);
-    break;
-  }
-
-  tor_free(desc);
- done:
-  SMARTLIST_FOREACH(args, char *, arg, tor_free(arg));
-  smartlist_free(args);
-  tor_free(cmdline);
-  return 0;
-}
-
-/** Called when we receive a REDIRECTSTERAM command.  Try to change the target
- * address of the named AP stream, and report success or failure. */
-static int
-handle_control_redirectstream(control_connection_t *conn, uint32_t len,
-                              const char *body)
-{
-  entry_connection_t *ap_conn = NULL;
-  char *new_addr = NULL;
-  uint16_t new_port = 0;
-  smartlist_t *args;
-  (void) len;
-
-  args = getargs_helper("REDIRECTSTREAM", conn, body, 2, -1);
-  if (!args)
-    return 0;
-
-  if (!(ap_conn = get_stream(smartlist_get(args, 0)))
-           || !ap_conn->socks_request) {
-    connection_printf_to_buf(conn, "552 Unknown stream \"%s\"\r\n",
-                             (char*)smartlist_get(args, 0));
-  } else {
-    int ok = 1;
-    if (smartlist_len(args) > 2) { /* they included a port too */
-      new_port = (uint16_t) tor_parse_ulong(smartlist_get(args, 2),
-                                            10, 1, 65535, &ok, NULL);
-    }
-    if (!ok) {
-      connection_printf_to_buf(conn, "512 Cannot parse port \"%s\"\r\n",
-                               (char*)smartlist_get(args, 2));
-    } else {
-      new_addr = tor_strdup(smartlist_get(args, 1));
-    }
-  }
-
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-  if (!new_addr)
-    return 0;
-
-  strlcpy(ap_conn->socks_request->address, new_addr,
-          sizeof(ap_conn->socks_request->address));
-  if (new_port)
-    ap_conn->socks_request->port = new_port;
-  tor_free(new_addr);
-  send_control_done(conn);
-  return 0;
-}
-
-/** Called when we get a CLOSESTREAM command; try to close the named stream
- * and report success or failure. */
-static int
-handle_control_closestream(control_connection_t *conn, uint32_t len,
-                           const char *body)
-{
-  entry_connection_t *ap_conn=NULL;
-  uint8_t reason=0;
-  smartlist_t *args;
-  int ok;
-  (void) len;
-
-  args = getargs_helper("CLOSESTREAM", conn, body, 2, -1);
-  if (!args)
-    return 0;
-
-  else if (!(ap_conn = get_stream(smartlist_get(args, 0))))
-    connection_printf_to_buf(conn, "552 Unknown stream \"%s\"\r\n",
-                             (char*)smartlist_get(args, 0));
-  else {
-    reason = (uint8_t) tor_parse_ulong(smartlist_get(args,1), 10, 0, 255,
-                                       &ok, NULL);
-    if (!ok) {
-      connection_printf_to_buf(conn, "552 Unrecognized reason \"%s\"\r\n",
-                               (char*)smartlist_get(args, 1));
-      ap_conn = NULL;
-    }
-  }
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-  if (!ap_conn)
-    return 0;
-
-  connection_mark_unattached_ap(ap_conn, reason);
-  send_control_done(conn);
-  return 0;
-}
-
-/** Called when we get a CLOSECIRCUIT command; try to close the named circuit
- * and report success or failure. */
-static int
-handle_control_closecircuit(control_connection_t *conn, uint32_t len,
-                            const char *body)
-{
-  origin_circuit_t *circ = NULL;
-  int safe = 0;
-  smartlist_t *args;
-  (void) len;
-
-  args = getargs_helper("CLOSECIRCUIT", conn, body, 1, -1);
-  if (!args)
-    return 0;
-
-  if (!(circ=get_circ(smartlist_get(args, 0))))
-    connection_printf_to_buf(conn, "552 Unknown circuit \"%s\"\r\n",
-                             (char*)smartlist_get(args, 0));
-  else {
-    int i;
-    for (i=1; i < smartlist_len(args); ++i) {
-      if (!strcasecmp(smartlist_get(args, i), "IfUnused"))
-        safe = 1;
-      else
-        log_info(LD_CONTROL, "Skipping unknown option %s",
-                 (char*)smartlist_get(args,i));
-    }
-  }
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-  if (!circ)
-    return 0;
-
-  if (!safe || !circ->p_streams) {
-    circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_REQUESTED);
-  }
-
-  send_control_done(conn);
-  return 0;
-}
-
-/** Called when we get a RESOLVE command: start trying to resolve
- * the listed addresses. */
-static int
-handle_control_resolve(control_connection_t *conn, uint32_t len,
-                       const char *body)
-{
-  smartlist_t *args, *failed;
-  int is_reverse = 0;
-  (void) len; /* body is nul-terminated; it's safe to ignore the length */
-
-  if (!(conn->event_mask & (((event_mask_t)1)<<EVENT_ADDRMAP))) {
-    log_warn(LD_CONTROL, "Controller asked us to resolve an address, but "
-             "isn't listening for ADDRMAP events.  It probably won't see "
-             "the answer.");
-  }
-  args = smartlist_new();
-  smartlist_split_string(args, body, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-  {
-    const char *modearg = find_element_starting_with(args, 0, "mode=");
-    if (modearg && !strcasecmp(modearg, "mode=reverse"))
-      is_reverse = 1;
-  }
-  failed = smartlist_new();
-  SMARTLIST_FOREACH(args, const char *, arg, {
-      if (!is_keyval_pair(arg)) {
-          if (dnsserv_launch_request(arg, is_reverse, conn)<0)
-            smartlist_add(failed, (char*)arg);
-      }
-  });
-
-  send_control_done(conn);
-  SMARTLIST_FOREACH(failed, const char *, arg, {
-      control_event_address_mapped(arg, arg, time(NULL),
-                                   "internal", 0);
-  });
-
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-  smartlist_free(failed);
-  return 0;
-}
-
-/** Called when we get a PROTOCOLINFO command: send back a reply. */
-static int
-handle_control_protocolinfo(control_connection_t *conn, uint32_t len,
-                            const char *body)
-{
-  const char *bad_arg = NULL;
-  smartlist_t *args;
-  (void)len;
-
-  conn->have_sent_protocolinfo = 1;
-  args = smartlist_new();
-  smartlist_split_string(args, body, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-  SMARTLIST_FOREACH(args, const char *, arg, {
-      int ok;
-      tor_parse_long(arg, 10, 0, LONG_MAX, &ok, NULL);
-      if (!ok) {
-        bad_arg = arg;
-        break;
-      }
-    });
-  if (bad_arg) {
-    connection_printf_to_buf(conn, "513 No such version %s\r\n",
-                             escaped(bad_arg));
-    /* Don't tolerate bad arguments when not authenticated. */
-    if (!STATE_IS_OPEN(TO_CONN(conn)->state))
-      connection_mark_for_close(TO_CONN(conn));
-    goto done;
-  } else {
-    const or_options_t *options = get_options();
-    int cookies = options->CookieAuthentication;
-    char *cfile = get_controller_cookie_file_name();
-    char *abs_cfile;
-    char *esc_cfile;
-    char *methods;
-    abs_cfile = make_path_absolute(cfile);
-    esc_cfile = esc_for_log(abs_cfile);
-    {
-      int passwd = (options->HashedControlPassword != NULL ||
-                    options->HashedControlSessionPassword != NULL);
-      smartlist_t *mlist = smartlist_new();
-      if (cookies) {
-        smartlist_add(mlist, (char*)"COOKIE");
-        smartlist_add(mlist, (char*)"SAFECOOKIE");
-      }
-      if (passwd)
-        smartlist_add(mlist, (char*)"HASHEDPASSWORD");
-      if (!cookies && !passwd)
-        smartlist_add(mlist, (char*)"NULL");
-      methods = smartlist_join_strings(mlist, ",", 0, NULL);
-      smartlist_free(mlist);
-    }
-
-    connection_printf_to_buf(conn,
-                             "250-PROTOCOLINFO 1\r\n"
-                             "250-AUTH METHODS=%s%s%s\r\n"
-                             "250-VERSION Tor=%s\r\n"
-                             "250 OK\r\n",
-                             methods,
-                             cookies?" COOKIEFILE=":"",
-                             cookies?esc_cfile:"",
-                             escaped(VERSION));
-    tor_free(methods);
-    tor_free(cfile);
-    tor_free(abs_cfile);
-    tor_free(esc_cfile);
-  }
- done:
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-  return 0;
-}
-
-/** Called when we get an AUTHCHALLENGE command. */
-static int
-handle_control_authchallenge(control_connection_t *conn, uint32_t len,
-                             const char *body)
-{
-  const char *cp = body;
-  char *client_nonce;
-  size_t client_nonce_len;
-  char server_hash[DIGEST256_LEN];
-  char server_hash_encoded[HEX_DIGEST256_LEN+1];
-  char server_nonce[SAFECOOKIE_SERVER_NONCE_LEN];
-  char server_nonce_encoded[(2*SAFECOOKIE_SERVER_NONCE_LEN) + 1];
-
-  cp += strspn(cp, " \t\n\r");
-  if (!strcasecmpstart(cp, "SAFECOOKIE")) {
-    cp += strlen("SAFECOOKIE");
-  } else {
-    connection_write_str_to_buf("513 AUTHCHALLENGE only supports SAFECOOKIE "
-                                "authentication\r\n", conn);
-    connection_mark_for_close(TO_CONN(conn));
-    return -1;
-  }
-
-  if (!authentication_cookie_is_set) {
-    connection_write_str_to_buf("515 Cookie authentication is disabled\r\n",
-                                conn);
-    connection_mark_for_close(TO_CONN(conn));
-    return -1;
-  }
-
-  cp += strspn(cp, " \t\n\r");
-  if (*cp == '"') {
-    const char *newcp =
-      decode_escaped_string(cp, len - (cp - body),
-                            &client_nonce, &client_nonce_len);
-    if (newcp == NULL) {
-      connection_write_str_to_buf("513 Invalid quoted client nonce\r\n",
-                                  conn);
-      connection_mark_for_close(TO_CONN(conn));
-      return -1;
-    }
-    cp = newcp;
-  } else {
-    size_t client_nonce_encoded_len = strspn(cp, "0123456789ABCDEFabcdef");
-
-    client_nonce_len = client_nonce_encoded_len / 2;
-    client_nonce = tor_malloc_zero(client_nonce_len);
-
-    if (base16_decode(client_nonce, client_nonce_len,
-                      cp, client_nonce_encoded_len)
-                      != (int) client_nonce_len) {
-      connection_write_str_to_buf("513 Invalid base16 client nonce\r\n",
-                                  conn);
-      connection_mark_for_close(TO_CONN(conn));
-      tor_free(client_nonce);
-      return -1;
-    }
-
-    cp += client_nonce_encoded_len;
-  }
-
-  cp += strspn(cp, " \t\n\r");
-  if (*cp != '\0' ||
-      cp != body + len) {
-    connection_write_str_to_buf("513 Junk at end of AUTHCHALLENGE command\r\n",
-                                conn);
-    connection_mark_for_close(TO_CONN(conn));
-    tor_free(client_nonce);
-    return -1;
-  }
-  crypto_rand(server_nonce, SAFECOOKIE_SERVER_NONCE_LEN);
-
-  /* Now compute and send the server-to-controller response, and the
-   * server's nonce. */
-  tor_assert(authentication_cookie != NULL);
-
-  {
-    size_t tmp_len = (AUTHENTICATION_COOKIE_LEN +
-                      client_nonce_len +
-                      SAFECOOKIE_SERVER_NONCE_LEN);
-    char *tmp = tor_malloc_zero(tmp_len);
-    char *client_hash = tor_malloc_zero(DIGEST256_LEN);
-    memcpy(tmp, authentication_cookie, AUTHENTICATION_COOKIE_LEN);
-    memcpy(tmp + AUTHENTICATION_COOKIE_LEN, client_nonce, client_nonce_len);
-    memcpy(tmp + AUTHENTICATION_COOKIE_LEN + client_nonce_len,
-           server_nonce, SAFECOOKIE_SERVER_NONCE_LEN);
-
-    crypto_hmac_sha256(server_hash,
-                       SAFECOOKIE_SERVER_TO_CONTROLLER_CONSTANT,
-                       strlen(SAFECOOKIE_SERVER_TO_CONTROLLER_CONSTANT),
-                       tmp,
-                       tmp_len);
-
-    crypto_hmac_sha256(client_hash,
-                       SAFECOOKIE_CONTROLLER_TO_SERVER_CONSTANT,
-                       strlen(SAFECOOKIE_CONTROLLER_TO_SERVER_CONSTANT),
-                       tmp,
-                       tmp_len);
-
-    conn->safecookie_client_hash = client_hash;
-
-    tor_free(tmp);
-  }
-
-  base16_encode(server_hash_encoded, sizeof(server_hash_encoded),
-                server_hash, sizeof(server_hash));
-  base16_encode(server_nonce_encoded, sizeof(server_nonce_encoded),
-                server_nonce, sizeof(server_nonce));
-
-  connection_printf_to_buf(conn,
-                           "250 AUTHCHALLENGE SERVERHASH=%s "
-                           "SERVERNONCE=%s\r\n",
-                           server_hash_encoded,
-                           server_nonce_encoded);
-
-  tor_free(client_nonce);
-  return 0;
-}
-
-/** Called when we get a USEFEATURE command: parse the feature list, and
- * set up the control_connection's options properly. */
-static int
-handle_control_usefeature(control_connection_t *conn,
-                          uint32_t len,
-                          const char *body)
-{
-  smartlist_t *args;
-  int bad = 0;
-  (void) len; /* body is nul-terminated; it's safe to ignore the length */
-  args = smartlist_new();
-  smartlist_split_string(args, body, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-  SMARTLIST_FOREACH_BEGIN(args, const char *, arg) {
-      if (!strcasecmp(arg, "VERBOSE_NAMES"))
-        ;
-      else if (!strcasecmp(arg, "EXTENDED_EVENTS"))
-        ;
-      else {
-        connection_printf_to_buf(conn, "552 Unrecognized feature \"%s\"\r\n",
-                                 arg);
-        bad = 1;
-        break;
-      }
-  } SMARTLIST_FOREACH_END(arg);
-
-  if (!bad) {
-    send_control_done(conn);
-  }
-
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-  return 0;
-}
-
-/** Implementation for the DROPGUARDS command. */
-static int
-handle_control_dropguards(control_connection_t *conn,
-                          uint32_t len,
-                          const char *body)
-{
-  smartlist_t *args;
-  (void) len; /* body is nul-terminated; it's safe to ignore the length */
-  args = smartlist_new();
-  smartlist_split_string(args, body, " ",
-                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-
-  static int have_warned = 0;
-  if (! have_warned) {
-    log_warn(LD_CONTROL, "DROPGUARDS is dangerous; make sure you understand "
-             "the risks before using it. It may be removed in a future "
-             "version of Tor.");
-    have_warned = 1;
-  }
-
-  if (smartlist_len(args)) {
-    connection_printf_to_buf(conn, "512 Too many arguments to DROPGUARDS\r\n");
-  } else {
-    remove_all_entry_guards();
-    send_control_done(conn);
-  }
-
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-  return 0;
-}
-
-/** Implementation for the HSFETCH command. */
-static int
-handle_control_hsfetch(control_connection_t *conn, uint32_t len,
-                       const char *body)
-{
-  int i;
-  char digest[DIGEST_LEN], *hsaddress = NULL, *arg1 = NULL, *desc_id = NULL;
-  smartlist_t *args = NULL, *hsdirs = NULL;
-  (void) len; /* body is nul-terminated; it's safe to ignore the length */
-  static const char *hsfetch_command = "HSFETCH";
-  static const char *v2_str = "v2-";
-  const size_t v2_str_len = strlen(v2_str);
-  rend_data_t *rend_query = NULL;
-
-  /* Make sure we have at least one argument, the HSAddress. */
-  args = getargs_helper(hsfetch_command, conn, body, 1, -1);
-  if (!args) {
-    goto exit;
-  }
-
-  /* Extract the first argument (either HSAddress or DescID). */
-  arg1 = smartlist_get(args, 0);
-  /* Test if it's an HS address without the .onion part. */
-  if (rend_valid_v2_service_id(arg1)) {
-    hsaddress = arg1;
-  } else if (strcmpstart(arg1, v2_str) == 0 &&
-             rend_valid_descriptor_id(arg1 + v2_str_len) &&
-             base32_decode(digest, sizeof(digest), arg1 + v2_str_len,
-                           REND_DESC_ID_V2_LEN_BASE32) == 0) {
-    /* We have a well formed version 2 descriptor ID. Keep the decoded value
-     * of the id. */
-    desc_id = digest;
-  } else {
-    connection_printf_to_buf(conn, "513 Invalid argument \"%s\"\r\n",
-                             arg1);
-    goto done;
-  }
-
-  static const char *opt_server = "SERVER=";
-
-  /* Skip first argument because it's the HSAddress or DescID. */
-  for (i = 1; i < smartlist_len(args); ++i) {
-    const char *arg = smartlist_get(args, i);
-    const node_t *node;
-
-    if (!strcasecmpstart(arg, opt_server)) {
-      const char *server;
-
-      server = arg + strlen(opt_server);
-      node = node_get_by_hex_id(server, 0);
-      if (!node) {
-        connection_printf_to_buf(conn, "552 Server \"%s\" not found\r\n",
-                                 server);
-        goto done;
-      }
-      if (!hsdirs) {
-        /* Stores routerstatus_t object for each specified server. */
-        hsdirs = smartlist_new();
-      }
-      /* Valid server, add it to our local list. */
-      smartlist_add(hsdirs, node->rs);
-    } else {
-      connection_printf_to_buf(conn, "513 Unexpected argument \"%s\"\r\n",
-                               arg);
-      goto done;
-    }
-  }
-
-  rend_query = rend_data_client_create(hsaddress, desc_id, NULL,
-                                       REND_NO_AUTH);
-  if (rend_query == NULL) {
-    connection_printf_to_buf(conn, "551 Error creating the HS query\r\n");
-    goto done;
-  }
-
-  /* Using a descriptor ID, we force the user to provide at least one
-   * hsdir server using the SERVER= option. */
-  if (desc_id && (!hsdirs || !smartlist_len(hsdirs))) {
-      connection_printf_to_buf(conn, "512 %s option is required\r\n",
-                               opt_server);
-      goto done;
-  }
-
-  /* We are about to trigger HSDir fetch so send the OK now because after
-   * that 650 event(s) are possible so better to have the 250 OK before them
-   * to avoid out of order replies. */
-  send_control_done(conn);
-
-  /* Trigger the fetch using the built rend query and possibly a list of HS
-   * directory to use. This function ignores the client cache thus this will
-   * always send a fetch command. */
-  rend_client_fetch_v2_desc(rend_query, hsdirs);
-
- done:
-  SMARTLIST_FOREACH(args, char *, cp, tor_free(cp));
-  smartlist_free(args);
-  /* Contains data pointer that we don't own thus no cleanup. */
-  smartlist_free(hsdirs);
-  rend_data_free(rend_query);
- exit:
-  return 0;
-}
-
-/** Implementation for the HSPOST command. */
-static int
-handle_control_hspost(control_connection_t *conn,
-                      uint32_t len,
-                      const char *body)
-{
-  static const char *opt_server = "SERVER=";
-  static const char *opt_hsaddress = "HSADDRESS=";
-  smartlist_t *hs_dirs = NULL;
-  const char *encoded_desc = body;
-  size_t encoded_desc_len = len;
-  const char *onion_address = NULL;
-
-  char *cp = memchr(body, '\n', len);
-  if (cp == NULL) {
-    connection_printf_to_buf(conn, "251 Empty body\r\n");
-    return 0;
-  }
-  char *argline = tor_strndup(body, cp-body);
-
-  smartlist_t *args = smartlist_new();
-
-  /* If any SERVER= or HSADDRESS= options were specified, try to parse
-   * the options line. */
-  if (!strcasecmpstart(argline, opt_server) ||
-      !strcasecmpstart(argline, opt_hsaddress)) {
-    /* encoded_desc begins after a newline character */
-    cp = cp + 1;
-    encoded_desc = cp;
-    encoded_desc_len = len-(cp-body);
-
-    smartlist_split_string(args, argline, " ",
-                           SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
-    SMARTLIST_FOREACH_BEGIN(args, const char *, arg) {
-      if (!strcasecmpstart(arg, opt_server)) {
-        const char *server = arg + strlen(opt_server);
-        const node_t *node = node_get_by_hex_id(server, 0);
-
-        if (!node || !node->rs) {
-          connection_printf_to_buf(conn, "552 Server \"%s\" not found\r\n",
-                                   server);
-          goto done;
-        }
-        /* Valid server, add it to our local list. */
-        if (!hs_dirs)
-          hs_dirs = smartlist_new();
-        smartlist_add(hs_dirs, node->rs);
-      } else if (!strcasecmpstart(arg, opt_hsaddress)) {
-        const char *address = arg + strlen(opt_hsaddress);
-        if (!hs_address_is_valid(address)) {
-          connection_printf_to_buf(conn, "512 Malformed onion address\r\n");
-          goto done;
-        }
-        onion_address = address;
-      } else {
-        connection_printf_to_buf(conn, "512 Unexpected argument \"%s\"\r\n",
-                                 arg);
-        goto done;
-      }
-    } SMARTLIST_FOREACH_END(arg);
-  }
-
-  /* Handle the v3 case. */
-  if (onion_address) {
-    char *desc_str = NULL;
-    read_escaped_data(encoded_desc, encoded_desc_len, &desc_str);
-    if (hs_control_hspost_command(desc_str, onion_address, hs_dirs) < 0) {
-      connection_printf_to_buf(conn, "554 Invalid descriptor\r\n");
-    } else {
-      send_control_done(conn);
-    }
-    tor_free(desc_str);
-    goto done;
-  }
-
-  /* From this point on, it is only v2. */
-
-  /* Read the dot encoded descriptor, and parse it. */
-  rend_encoded_v2_service_descriptor_t *desc =
-      tor_malloc_zero(sizeof(rend_encoded_v2_service_descriptor_t));
-  read_escaped_data(encoded_desc, encoded_desc_len, &desc->desc_str);
-
-  rend_service_descriptor_t *parsed = NULL;
-  char *intro_content = NULL;
-  size_t intro_size;
-  size_t encoded_size;
-  const char *next_desc;
-  if (!rend_parse_v2_service_descriptor(&parsed, desc->desc_id, &intro_content,
-                                        &intro_size, &encoded_size,
-                                        &next_desc, desc->desc_str, 1)) {
-    /* Post the descriptor. */
-    char serviceid[REND_SERVICE_ID_LEN_BASE32+1];
-    if (!rend_get_service_id(parsed->pk, serviceid)) {
-      smartlist_t *descs = smartlist_new();
-      smartlist_add(descs, desc);
-
-      /* We are about to trigger HS descriptor upload so send the OK now
-       * because after that 650 event(s) are possible so better to have the
-       * 250 OK before them to avoid out of order replies. */
-      send_control_done(conn);
-
-      /* Trigger the descriptor upload */
-      directory_post_to_hs_dir(parsed, descs, hs_dirs, serviceid, 0);
-      smartlist_free(descs);
-    }
-
-    rend_service_descriptor_free(parsed);
-  } else {
-    connection_printf_to_buf(conn, "554 Invalid descriptor\r\n");
-  }
-
-  tor_free(intro_content);
-  rend_encoded_v2_service_descriptor_free(desc);
- done:
-  tor_free(argline);
-  smartlist_free(hs_dirs); /* Contents belong to the rend service code. */
-  SMARTLIST_FOREACH(args, char *, arg, tor_free(arg));
-  smartlist_free(args);
-  return 0;
-}
-
-/* Helper function for ADD_ONION that adds an ephemeral service depending on
- * the given hs_version.
- *
- * The secret key in pk depends on the hs_version. The ownership of the key
- * used in pk is given to the HS subsystem so the caller must stop accessing
- * it after.
- *
- * The port_cfgs is a list of service port. Ownership transferred to service.
- * The max_streams refers to the MaxStreams= key.
- * The max_streams_close_circuit refers to the MaxStreamsCloseCircuit key.
- * The auth_type is the authentication type of the clients in auth_clients.
- * The ownership of that list is transferred to the service.
- *
- * On success (RSAE_OKAY), the address_out points to a newly allocated string
- * containing the onion address without the .onion part. On error, address_out
- * is untouched. */
-static hs_service_add_ephemeral_status_t
-add_onion_helper_add_service(int hs_version,
-                             add_onion_secret_key_t *pk,
-                             smartlist_t *port_cfgs, int max_streams,
-                             int max_streams_close_circuit, int auth_type,
-                             smartlist_t *auth_clients, char **address_out)
-{
-  hs_service_add_ephemeral_status_t ret;
-
-  tor_assert(pk);
-  tor_assert(port_cfgs);
-  tor_assert(address_out);
-
-  switch (hs_version) {
-  case HS_VERSION_TWO:
-    ret = rend_service_add_ephemeral(pk->v2, port_cfgs, max_streams,
-                                     max_streams_close_circuit, auth_type,
-                                     auth_clients, address_out);
-    break;
-  case HS_VERSION_THREE:
-    ret = hs_service_add_ephemeral(pk->v3, port_cfgs, max_streams,
-                                   max_streams_close_circuit, address_out);
-    break;
-  default:
-    tor_assert_unreached();
-  }
-
-  return ret;
-}
-
-/** Called when we get a ADD_ONION command; parse the body, and set up
- * the new ephemeral Onion Service. */
-static int
-handle_control_add_onion(control_connection_t *conn,
-                         uint32_t len,
-                         const char *body)
-{
-  smartlist_t *args;
-  int arg_len;
-  (void) len; /* body is nul-terminated; it's safe to ignore the length */
-  args = getargs_helper("ADD_ONION", conn, body, 2, -1);
-  if (!args)
-    return 0;
-  arg_len = smartlist_len(args);
-
-  /* Parse all of the arguments that do not involve handling cryptographic
-   * material first, since there's no reason to touch that at all if any of
-   * the other arguments are malformed.
-   */
-  smartlist_t *port_cfgs = smartlist_new();
-  smartlist_t *auth_clients = NULL;
-  smartlist_t *auth_created_clients = NULL;
-  int discard_pk = 0;
-  int detach = 0;
-  int max_streams = 0;
-  int max_streams_close_circuit = 0;
-  rend_auth_type_t auth_type = REND_NO_AUTH;
-  /* Default to adding an anonymous hidden service if no flag is given */
-  int non_anonymous = 0;
-  for (int i = 1; i < arg_len; i++) {
-    static const char *port_prefix = "Port=";
-    static const char *flags_prefix = "Flags=";
-    static const char *max_s_prefix = "MaxStreams=";
-    static const char *auth_prefix = "ClientAuth=";
-
-    const char *arg = smartlist_get(args, (int)i);
-    if (!strcasecmpstart(arg, port_prefix)) {
-      /* "Port=VIRTPORT[,TARGET]". */
-      const char *port_str = arg + strlen(port_prefix);
-
-      rend_service_port_config_t *cfg =
-          rend_service_parse_port_config(port_str, ",", NULL);
-      if (!cfg) {
-        connection_printf_to_buf(conn, "512 Invalid VIRTPORT/TARGET\r\n");
-        goto out;
-      }
-      smartlist_add(port_cfgs, cfg);
-    } else if (!strcasecmpstart(arg, max_s_prefix)) {
-      /* "MaxStreams=[0..65535]". */
-      const char *max_s_str = arg + strlen(max_s_prefix);
-      int ok = 0;
-      max_streams = (int)tor_parse_long(max_s_str, 10, 0, 65535, &ok, NULL);
-      if (!ok) {
-        connection_printf_to_buf(conn, "512 Invalid MaxStreams\r\n");
-        goto out;
-      }
-    } else if (!strcasecmpstart(arg, flags_prefix)) {
-      /* "Flags=Flag[,Flag]", where Flag can be:
-       *   * 'DiscardPK' - If tor generates the keypair, do not include it in
-       *                   the response.
-       *   * 'Detach' - Do not tie this onion service to any particular control
-       *                connection.
-       *   * 'MaxStreamsCloseCircuit' - Close the circuit if MaxStreams is
-       *                                exceeded.
-       *   * 'BasicAuth' - Client authorization using the 'basic' method.
-       *   * 'NonAnonymous' - Add a non-anonymous Single Onion Service. If this
-       *                      flag is present, tor must be in non-anonymous
-       *                      hidden service mode. If this flag is absent,
-       *                      tor must be in anonymous hidden service mode.
-       */
-      static const char *discard_flag = "DiscardPK";
-      static const char *detach_flag = "Detach";
-      static const char *max_s_close_flag = "MaxStreamsCloseCircuit";
-      static const char *basicauth_flag = "BasicAuth";
-      static const char *non_anonymous_flag = "NonAnonymous";
-
-      smartlist_t *flags = smartlist_new();
-      int bad = 0;
-
-      smartlist_split_string(flags, arg + strlen(flags_prefix), ",",
-                             SPLIT_IGNORE_BLANK, 0);
-      if (smartlist_len(flags) < 1) {
-        connection_printf_to_buf(conn, "512 Invalid 'Flags' argument\r\n");
-        bad = 1;
-      }
-      SMARTLIST_FOREACH_BEGIN(flags, const char *, flag)
-      {
-        if (!strcasecmp(flag, discard_flag)) {
-          discard_pk = 1;
-        } else if (!strcasecmp(flag, detach_flag)) {
-          detach = 1;
-        } else if (!strcasecmp(flag, max_s_close_flag)) {
-          max_streams_close_circuit = 1;
-        } else if (!strcasecmp(flag, basicauth_flag)) {
-          auth_type = REND_BASIC_AUTH;
-        } else if (!strcasecmp(flag, non_anonymous_flag)) {
-          non_anonymous = 1;
-        } else {
-          connection_printf_to_buf(conn,
-                                   "512 Invalid 'Flags' argument: %s\r\n",
-                                   escaped(flag));
-          bad = 1;
-          break;
-        }
-      } SMARTLIST_FOREACH_END(flag);
-      SMARTLIST_FOREACH(flags, char *, cp, tor_free(cp));
-      smartlist_free(flags);
-      if (bad)
-        goto out;
-    } else if (!strcasecmpstart(arg, auth_prefix)) {
-      char *err_msg = NULL;
-      int created = 0;
-      rend_authorized_client_t *client =
-        add_onion_helper_clientauth(arg + strlen(auth_prefix),
-                                    &created, &err_msg);
-      if (!client) {
-        if (err_msg) {
-          connection_write_str_to_buf(err_msg, conn);
-          tor_free(err_msg);
-        }
-        goto out;
-      }
-
-      if (auth_clients != NULL) {
-        int bad = 0;
-        SMARTLIST_FOREACH_BEGIN(auth_clients, rend_authorized_client_t *, ac) {
-          if (strcmp(ac->client_name, client->client_name) == 0) {
-            bad = 1;
-            break;
-          }
-        } SMARTLIST_FOREACH_END(ac);
-        if (bad) {
-          connection_printf_to_buf(conn,
-                                   "512 Duplicate name in ClientAuth\r\n");
-          rend_authorized_client_free(client);
-          goto out;
-        }
-      } else {
-        auth_clients = smartlist_new();
-        auth_created_clients = smartlist_new();
-      }
-      smartlist_add(auth_clients, client);
-      if (created) {
-        smartlist_add(auth_created_clients, client);
-      }
-    } else {
-      connection_printf_to_buf(conn, "513 Invalid argument\r\n");
-      goto out;
-    }
-  }
-  if (smartlist_len(port_cfgs) == 0) {
-    connection_printf_to_buf(conn, "512 Missing 'Port' argument\r\n");
-    goto out;
-  } else if (auth_type == REND_NO_AUTH && auth_clients != NULL) {
-    connection_printf_to_buf(conn, "512 No auth type specified\r\n");
-    goto out;
-  } else if (auth_type != REND_NO_AUTH && auth_clients == NULL) {
-    connection_printf_to_buf(conn, "512 No auth clients specified\r\n");
-    goto out;
-  } else if ((auth_type == REND_BASIC_AUTH &&
-              smartlist_len(auth_clients) > 512) ||
-             (auth_type == REND_STEALTH_AUTH &&
-              smartlist_len(auth_clients) > 16)) {
-    connection_printf_to_buf(conn, "512 Too many auth clients\r\n");
-    goto out;
-  } else if (non_anonymous != rend_service_non_anonymous_mode_enabled(
-                                                              get_options())) {
-    /* If we failed, and the non-anonymous flag is set, Tor must be in
-     * anonymous hidden service mode.
-     * The error message changes based on the current Tor config:
-     * 512 Tor is in anonymous hidden service mode
-     * 512 Tor is in non-anonymous hidden service mode
-     * (I've deliberately written them out in full here to aid searchability.)
-     */
-    connection_printf_to_buf(conn, "512 Tor is in %sanonymous hidden service "
-                             "mode\r\n",
-                             non_anonymous ? "" : "non-");
-    goto out;
-  }
-
-  /* Parse the "keytype:keyblob" argument. */
-  int hs_version = 0;
-  add_onion_secret_key_t pk = { NULL };
-  const char *key_new_alg = NULL;
-  char *key_new_blob = NULL;
-  char *err_msg = NULL;
-
-  if (add_onion_helper_keyarg(smartlist_get(args, 0), discard_pk,
-                              &key_new_alg, &key_new_blob, &pk, &hs_version,
-                              &err_msg) < 0) {
-    if (err_msg) {
-      connection_write_str_to_buf(err_msg, conn);
-      tor_free(err_msg);
-    }
-    goto out;
-  }
-  tor_assert(!err_msg);
-
-  /* Hidden service version 3 don't have client authentication support so if
-   * ClientAuth was given, send back an error. */
-  if (hs_version == HS_VERSION_THREE && auth_clients) {
-    connection_printf_to_buf(conn, "513 ClientAuth not supported\r\n");
-    goto out;
-  }
-
-  /* Create the HS, using private key pk, client authentication auth_type,
-   * the list of auth_clients, and port config port_cfg.
-   * rend_service_add_ephemeral() will take ownership of pk and port_cfg,
-   * regardless of success/failure.
-   */
-  char *service_id = NULL;
-  int ret = add_onion_helper_add_service(hs_version, &pk, port_cfgs,
-                                         max_streams,
-                                         max_streams_close_circuit, auth_type,
-                                         auth_clients, &service_id);
-  port_cfgs = NULL; /* port_cfgs is now owned by the rendservice code. */
-  auth_clients = NULL; /* so is auth_clients */
-  switch (ret) {
-  case RSAE_OKAY:
-  {
-    if (detach) {
-      if (!detached_onion_services)
-        detached_onion_services = smartlist_new();
-      smartlist_add(detached_onion_services, service_id);
-    } else {
-      if (!conn->ephemeral_onion_services)
-        conn->ephemeral_onion_services = smartlist_new();
-      smartlist_add(conn->ephemeral_onion_services, service_id);
-    }
-
-    tor_assert(service_id);
-    connection_printf_to_buf(conn, "250-ServiceID=%s\r\n", service_id);
-    if (key_new_alg) {
-      tor_assert(key_new_blob);
-      connection_printf_to_buf(conn, "250-PrivateKey=%s:%s\r\n",
-                               key_new_alg, key_new_blob);
-    }
-    if (auth_created_clients) {
-      SMARTLIST_FOREACH(auth_created_clients, rend_authorized_client_t *, ac, {
-        char *encoded = rend_auth_encode_cookie(ac->descriptor_cookie,
-                                                auth_type);
-        tor_assert(encoded);
-        connection_printf_to_buf(conn, "250-ClientAuth=%s:%s\r\n",
-                                 ac->client_name, encoded);
-        memwipe(encoded, 0, strlen(encoded));
-        tor_free(encoded);
-      });
-    }
-
-    connection_printf_to_buf(conn, "250 OK\r\n");
-    break;
-  }
-  case RSAE_BADPRIVKEY:
-    connection_printf_to_buf(conn, "551 Failed to generate onion address\r\n");
-    break;
-  case RSAE_ADDREXISTS:
-    connection_printf_to_buf(conn, "550 Onion address collision\r\n");
-    break;
-  case RSAE_BADVIRTPORT:
-    connection_printf_to_buf(conn, "512 Invalid VIRTPORT/TARGET\r\n");
-    break;
-  case RSAE_BADAUTH:
-    connection_printf_to_buf(conn, "512 Invalid client authorization\r\n");
-    break;
-  case RSAE_INTERNAL: /* FALLSTHROUGH */
-  default:
-    connection_printf_to_buf(conn, "551 Failed to add Onion Service\r\n");
-  }
-  if (key_new_blob) {
-    memwipe(key_new_blob, 0, strlen(key_new_blob));
-    tor_free(key_new_blob);
-  }
-
- out:
-  if (port_cfgs) {
-    SMARTLIST_FOREACH(port_cfgs, rend_service_port_config_t*, p,
-                      rend_service_port_config_free(p));
-    smartlist_free(port_cfgs);
-  }
-
-  if (auth_clients) {
-    SMARTLIST_FOREACH(auth_clients, rend_authorized_client_t *, ac,
-                      rend_authorized_client_free(ac));
-    smartlist_free(auth_clients);
-  }
-  if (auth_created_clients) {
-    // Do not free entries; they are the same as auth_clients
-    smartlist_free(auth_created_clients);
-  }
-
-  SMARTLIST_FOREACH(args, char *, cp, {
-    memwipe(cp, 0, strlen(cp));
-    tor_free(cp);
-  });
-  smartlist_free(args);
-  return 0;
-}
-
-/** Helper function to handle parsing the KeyType:KeyBlob argument to the
- * ADD_ONION command. Return a new crypto_pk_t and if a new key was generated
- * and the private key not discarded, the algorithm and serialized private key,
- * or NULL and an optional control protocol error message on failure.  The
- * caller is responsible for freeing the returned key_new_blob and err_msg.
- *
- * Note: The error messages returned are deliberately vague to avoid echoing
- * key material.
- */
-STATIC int
-add_onion_helper_keyarg(const char *arg, int discard_pk,
-                        const char **key_new_alg_out, char **key_new_blob_out,
-                        add_onion_secret_key_t *decoded_key, int *hs_version,
-                        char **err_msg_out)
-{
-  smartlist_t *key_args = smartlist_new();
-  crypto_pk_t *pk = NULL;
-  const char *key_new_alg = NULL;
-  char *key_new_blob = NULL;
-  char *err_msg = NULL;
-  int ret = -1;
-
-  smartlist_split_string(key_args, arg, ":", SPLIT_IGNORE_BLANK, 0);
-  if (smartlist_len(key_args) != 2) {
-    err_msg = tor_strdup("512 Invalid key type/blob\r\n");
-    goto err;
-  }
-
-  /* The format is "KeyType:KeyBlob". */
-  static const char *key_type_new = "NEW";
-  static const char *key_type_best = "BEST";
-  static const char *key_type_rsa1024 = "RSA1024";
-  static const char *key_type_ed25519_v3 = "ED25519-V3";
-
-  const char *key_type = smartlist_get(key_args, 0);
-  const char *key_blob = smartlist_get(key_args, 1);
-
-  if (!strcasecmp(key_type_rsa1024, key_type)) {
-    /* "RSA:<Base64 Blob>" - Loading a pre-existing RSA1024 key. */
-    pk = crypto_pk_base64_decode_private(key_blob, strlen(key_blob));
-    if (!pk) {
-      err_msg = tor_strdup("512 Failed to decode RSA key\r\n");
-      goto err;
-    }
-    if (crypto_pk_num_bits(pk) != PK_BYTES*8) {
-      crypto_pk_free(pk);
-      err_msg = tor_strdup("512 Invalid RSA key size\r\n");
-      goto err;
-    }
-    decoded_key->v2 = pk;
-    *hs_version = HS_VERSION_TWO;
-  } else if (!strcasecmp(key_type_ed25519_v3, key_type)) {
-    /* "ED25519-V3:<Base64 Blob>" - Loading a pre-existing ed25519 key. */
-    ed25519_secret_key_t *sk = tor_malloc_zero(sizeof(*sk));
-    if (base64_decode((char *) sk->seckey, sizeof(sk->seckey), key_blob,
-                      strlen(key_blob)) != sizeof(sk->seckey)) {
-      tor_free(sk);
-      err_msg = tor_strdup("512 Failed to decode ED25519-V3 key\r\n");
-      goto err;
-    }
-    decoded_key->v3 = sk;
-    *hs_version = HS_VERSION_THREE;
-  } else if (!strcasecmp(key_type_new, key_type)) {
-    /* "NEW:<Algorithm>" - Generating a new key, blob as algorithm. */
-    if (!strcasecmp(key_type_rsa1024, key_blob) ||
-        !strcasecmp(key_type_best, key_blob)) {
-      /* "RSA1024", RSA 1024 bit, also currently "BEST" by default. */
-      pk = crypto_pk_new();
-      if (crypto_pk_generate_key(pk)) {
-        tor_asprintf(&err_msg, "551 Failed to generate %s key\r\n",
-                     key_type_rsa1024);
-        goto err;
-      }
-      if (!discard_pk) {
-        if (crypto_pk_base64_encode_private(pk, &key_new_blob)) {
-          crypto_pk_free(pk);
-          tor_asprintf(&err_msg, "551 Failed to encode %s key\r\n",
-                       key_type_rsa1024);
-          goto err;
-        }
-        key_new_alg = key_type_rsa1024;
-      }
-      decoded_key->v2 = pk;
-      *hs_version = HS_VERSION_TWO;
-    } else if (!strcasecmp(key_type_ed25519_v3, key_blob)) {
-      ed25519_secret_key_t *sk = tor_malloc_zero(sizeof(*sk));
-      if (ed25519_secret_key_generate(sk, 1) < 0) {
-        tor_free(sk);
-        tor_asprintf(&err_msg, "551 Failed to generate %s key\r\n",
-                     key_type_ed25519_v3);
-        goto err;
-      }
-      if (!discard_pk) {
-        ssize_t len = base64_encode_size(sizeof(sk->seckey), 0) + 1;
-        key_new_blob = tor_malloc_zero(len);
-        if (base64_encode(key_new_blob, len, (const char *) sk->seckey,
-                          sizeof(sk->seckey), 0) != (len - 1)) {
-          tor_free(sk);
-          tor_free(key_new_blob);
-          tor_asprintf(&err_msg, "551 Failed to encode %s key\r\n",
-                       key_type_ed25519_v3);
-          goto err;
-        }
-        key_new_alg = key_type_ed25519_v3;
-      }
-      decoded_key->v3 = sk;
-      *hs_version = HS_VERSION_THREE;
-    } else {
-      err_msg = tor_strdup("513 Invalid key type\r\n");
-      goto err;
-    }
-  } else {
-    err_msg = tor_strdup("513 Invalid key type\r\n");
-    goto err;
-  }
-
-  /* Succeeded in loading or generating a private key. */
-  ret = 0;
-
- err:
-  SMARTLIST_FOREACH(key_args, char *, cp, {
-    memwipe(cp, 0, strlen(cp));
-    tor_free(cp);
-  });
-  smartlist_free(key_args);
-
-  if (err_msg_out) {
-    *err_msg_out = err_msg;
-  } else {
-    tor_free(err_msg);
-  }
-  *key_new_alg_out = key_new_alg;
-  *key_new_blob_out = key_new_blob;
-
-  return ret;
-}
-
-/** Helper function to handle parsing a ClientAuth argument to the
- * ADD_ONION command.  Return a new rend_authorized_client_t, or NULL
- * and an optional control protocol error message on failure.  The
- * caller is responsible for freeing the returned auth_client and err_msg.
- *
- * If 'created' is specified, it will be set to 1 when a new cookie has
- * been generated.
- */
-STATIC rend_authorized_client_t *
-add_onion_helper_clientauth(const char *arg, int *created, char **err_msg)
-{
-  int ok = 0;
-
-  tor_assert(arg);
-  tor_assert(created);
-  tor_assert(err_msg);
-  *err_msg = NULL;
-
-  smartlist_t *auth_args = smartlist_new();
-  rend_authorized_client_t *client =
-    tor_malloc_zero(sizeof(rend_authorized_client_t));
-  smartlist_split_string(auth_args, arg, ":", 0, 0);
-  if (smartlist_len(auth_args) < 1 || smartlist_len(auth_args) > 2) {
-    *err_msg = tor_strdup("512 Invalid ClientAuth syntax\r\n");
-    goto err;
-  }
-  client->client_name = tor_strdup(smartlist_get(auth_args, 0));
-  if (smartlist_len(auth_args) == 2) {
-    char *decode_err_msg = NULL;
-    if (rend_auth_decode_cookie(smartlist_get(auth_args, 1),
-                                client->descriptor_cookie,
-                                NULL, &decode_err_msg) < 0) {
-      tor_assert(decode_err_msg);
-      tor_asprintf(err_msg, "512 %s\r\n", decode_err_msg);
-      tor_free(decode_err_msg);
-      goto err;
-    }
-    *created = 0;
-  } else {
-    crypto_rand((char *) client->descriptor_cookie, REND_DESC_COOKIE_LEN);
-    *created = 1;
-  }
-
-  if (!rend_valid_client_name(client->client_name)) {
-    *err_msg = tor_strdup("512 Invalid name in ClientAuth\r\n");
-    goto err;
-  }
-
-  ok = 1;
- err:
-  SMARTLIST_FOREACH(auth_args, char *, item, tor_free(item));
-  smartlist_free(auth_args);
-  if (!ok) {
-    rend_authorized_client_free(client);
-    client = NULL;
-  }
-  return client;
-}
-
-/** Called when we get a DEL_ONION command; parse the body, and remove
- * the existing ephemeral Onion Service. */
-static int
-handle_control_del_onion(control_connection_t *conn,
-                          uint32_t len,
-                          const char *body)
-{
-  int hs_version = 0;
-  smartlist_t *args;
-  (void) len; /* body is nul-terminated; it's safe to ignore the length */
-  args = getargs_helper("DEL_ONION", conn, body, 1, 1);
-  if (!args)
-    return 0;
-
-  const char *service_id = smartlist_get(args, 0);
-  if (rend_valid_v2_service_id(service_id)) {
-    hs_version = HS_VERSION_TWO;
-  } else if (hs_address_is_valid(service_id)) {
-    hs_version = HS_VERSION_THREE;
-  } else {
-    connection_printf_to_buf(conn, "512 Malformed Onion Service id\r\n");
-    goto out;
-  }
-
-  /* Determine if the onion service belongs to this particular control
-   * connection, or if it is in the global list of detached services.  If it
-   * is in neither, either the service ID is invalid in some way, or it
-   * explicitly belongs to a different control connection, and an error
-   * should be returned.
-   */
-  smartlist_t *services[2] = {
-    conn->ephemeral_onion_services,
-    detached_onion_services
-  };
-  smartlist_t *onion_services = NULL;
-  int idx = -1;
-  for (size_t i = 0; i < ARRAY_LENGTH(services); i++) {
-    idx = smartlist_string_pos(services[i], service_id);
-    if (idx != -1) {
-      onion_services = services[i];
-      break;
-    }
-  }
-  if (onion_services == NULL) {
-    connection_printf_to_buf(conn, "552 Unknown Onion Service id\r\n");
-  } else {
-    int ret = -1;
-    switch (hs_version) {
-    case HS_VERSION_TWO:
-      ret = rend_service_del_ephemeral(service_id);
-      break;
-    case HS_VERSION_THREE:
-      ret = hs_service_del_ephemeral(service_id);
-      break;
-    default:
-      /* The ret value will be -1 thus hitting the warning below. This should
-       * never happen because of the check at the start of the function. */
-      break;
-    }
-    if (ret < 0) {
-      /* This should *NEVER* fail, since the service is on either the
-       * per-control connection list, or the global one.
-       */
-      log_warn(LD_BUG, "Failed to remove Onion Service %s.",
-               escaped(service_id));
-      tor_fragile_assert();
-    }
-
-    /* Remove/scrub the service_id from the appropriate list. */
-    char *cp = smartlist_get(onion_services, idx);
-    smartlist_del(onion_services, idx);
-    memwipe(cp, 0, strlen(cp));
-    tor_free(cp);
-
-    send_control_done(conn);
-  }
-
- out:
-  SMARTLIST_FOREACH(args, char *, cp, {
-    memwipe(cp, 0, strlen(cp));
-    tor_free(cp);
-  });
-  smartlist_free(args);
-  return 0;
-}
-
-/** Called when <b>conn</b> has no more bytes left on its outbuf. */
-int
-connection_control_finished_flushing(control_connection_t *conn)
-{
-  tor_assert(conn);
-  return 0;
-}
-
-/** Called when <b>conn</b> has gotten its socket closed. */
-int
-connection_control_reached_eof(control_connection_t *conn)
-{
-  tor_assert(conn);
-
-  log_info(LD_CONTROL,"Control connection reached EOF. Closing.");
-  connection_mark_for_close(TO_CONN(conn));
-  return 0;
-}
-
-/** Shut down this Tor instance in the same way that SIGINT would, but
- * with a log message appropriate for the loss of an owning controller. */
-static void
-lost_owning_controller(const char *owner_type, const char *loss_manner)
-{
-  log_notice(LD_CONTROL, "Owning controller %s has %s -- exiting now.",
-             owner_type, loss_manner);
-
-  activate_signal(SIGTERM);
-}
-
-/** Called when <b>conn</b> is being freed. */
-void
-connection_control_closed(control_connection_t *conn)
-{
-  tor_assert(conn);
-
-  conn->event_mask = 0;
-  control_update_global_event_mask();
-
-  /* Close all ephemeral Onion Services if any.
-   * The list and it's contents are scrubbed/freed in connection_free_.
-   */
-  if (conn->ephemeral_onion_services) {
-    SMARTLIST_FOREACH_BEGIN(conn->ephemeral_onion_services, char *, cp) {
-      if (rend_valid_v2_service_id(cp)) {
-        rend_service_del_ephemeral(cp);
-      } else if (hs_address_is_valid(cp)) {
-        hs_service_del_ephemeral(cp);
-      } else {
-        /* An invalid .onion in our list should NEVER happen */
-        tor_fragile_assert();
-      }
-    } SMARTLIST_FOREACH_END(cp);
-  }
-
-  if (conn->is_owning_control_connection) {
-    lost_owning_controller("connection", "closed");
-  }
-}
-
-/** Return true iff <b>cmd</b> is allowable (or at least forgivable) at this
- * stage of the protocol. */
-static int
-is_valid_initial_command(control_connection_t *conn, const char *cmd)
-{
-  if (conn->base_.state == CONTROL_CONN_STATE_OPEN)
-    return 1;
-  if (!strcasecmp(cmd, "PROTOCOLINFO"))
-    return (!conn->have_sent_protocolinfo &&
-            conn->safecookie_client_hash == NULL);
-  if (!strcasecmp(cmd, "AUTHCHALLENGE"))
-    return (conn->safecookie_client_hash == NULL);
-  if (!strcasecmp(cmd, "AUTHENTICATE") ||
-      !strcasecmp(cmd, "QUIT"))
-    return 1;
-  return 0;
-}
-
-/** Do not accept any control command of more than 1MB in length.  Anything
- * that needs to be anywhere near this long probably means that one of our
- * interfaces is broken. */
-#define MAX_COMMAND_LINE_LENGTH (1024*1024)
-
-/** Wrapper around peek_buf_has_control0 command: presents the same
- * interface as that underlying functions, but takes a connection_t intead of
- * a buf_t.
- */
-static int
-peek_connection_has_control0_command(connection_t *conn)
-{
-  return peek_buf_has_control0_command(conn->inbuf);
-}
-
-static int
-peek_connection_has_http_command(connection_t *conn)
-{
-  return peek_buf_has_http_command(conn->inbuf);
-}
-
-static const char CONTROLPORT_IS_NOT_AN_HTTP_PROXY_MSG[] =
-  "HTTP/1.0 501 Tor ControlPort is not an HTTP proxy"
-  "\r\nContent-Type: text/html; charset=iso-8859-1\r\n\r\n"
-  "<html>\n"
-  "<head>\n"
-  "<title>Tor's ControlPort is not an HTTP proxy</title>\n"
-  "</head>\n"
-  "<body>\n"
-  "<h1>Tor's ControlPort is not an HTTP proxy</h1>\n"
-  "<p>\n"
-  "It appears you have configured your web browser to use Tor's control port"
-  " as an HTTP proxy.\n"
-  "This is not correct: Tor's default SOCKS proxy port is 9050.\n"
-  "Please configure your client accordingly.\n"
-  "</p>\n"
-  "<p>\n"
-  "See <a href=\"https://www.torproject.org/documentation.html\">"
-  "https://www.torproject.org/documentation.html</a> for more "
-  "information.\n"
-  "<!-- Plus this comment, to make the body response more than 512 bytes, so "
-  "     IE will be willing to display it. Comment comment comment comment "
-  "     comment comment comment comment comment comment comment comment.-->\n"
-  "</p>\n"
-  "</body>\n"
-  "</html>\n";
-
-/** Called when data has arrived on a v1 control connection: Try to fetch
- * commands from conn->inbuf, and execute them.
- */
-int
-connection_control_process_inbuf(control_connection_t *conn)
-{
-  size_t data_len;
-  uint32_t cmd_data_len;
-  int cmd_len;
-  char *args;
-
-  tor_assert(conn);
-  tor_assert(conn->base_.state == CONTROL_CONN_STATE_OPEN ||
-             conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH);
-
-  if (!conn->incoming_cmd) {
-    conn->incoming_cmd = tor_malloc(1024);
-    conn->incoming_cmd_len = 1024;
-    conn->incoming_cmd_cur_len = 0;
-  }
-
-  if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH &&
-      peek_connection_has_control0_command(TO_CONN(conn))) {
-    /* Detect v0 commands and send a "no more v0" message. */
-    size_t body_len;
-    char buf[128];
-    set_uint16(buf+2, htons(0x0000)); /* type == error */
-    set_uint16(buf+4, htons(0x0001)); /* code == internal error */
-    strlcpy(buf+6, "The v0 control protocol is not supported by Tor 0.1.2.17 "
-            "and later; upgrade your controller.",
-            sizeof(buf)-6);
-    body_len = 2+strlen(buf+6)+2; /* code, msg, nul. */
-    set_uint16(buf+0, htons(body_len));
-    connection_buf_add(buf, 4+body_len, TO_CONN(conn));
-
-    connection_mark_and_flush(TO_CONN(conn));
-    return 0;
-  }
-
-  /* If the user has the HTTP proxy port and the control port confused. */
-  if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH &&
-      peek_connection_has_http_command(TO_CONN(conn))) {
-    connection_write_str_to_buf(CONTROLPORT_IS_NOT_AN_HTTP_PROXY_MSG, conn);
-    log_notice(LD_CONTROL, "Received HTTP request on ControlPort");
-    connection_mark_and_flush(TO_CONN(conn));
-    return 0;
-  }
-
- again:
-  while (1) {
-    size_t last_idx;
-    int r;
-    /* First, fetch a line. */
-    do {
-      data_len = conn->incoming_cmd_len - conn->incoming_cmd_cur_len;
-      r = connection_buf_get_line(TO_CONN(conn),
-                              conn->incoming_cmd+conn->incoming_cmd_cur_len,
-                              &data_len);
-      if (r == 0)
-        /* Line not all here yet. Wait. */
-        return 0;
-      else if (r == -1) {
-        if (data_len + conn->incoming_cmd_cur_len > MAX_COMMAND_LINE_LENGTH) {
-          connection_write_str_to_buf("500 Line too long.\r\n", conn);
-          connection_stop_reading(TO_CONN(conn));
-          connection_mark_and_flush(TO_CONN(conn));
-        }
-        while (conn->incoming_cmd_len < data_len+conn->incoming_cmd_cur_len)
-          conn->incoming_cmd_len *= 2;
-        conn->incoming_cmd = tor_realloc(conn->incoming_cmd,
-                                         conn->incoming_cmd_len);
-      }
-    } while (r != 1);
-
-    tor_assert(data_len);
-
-    last_idx = conn->incoming_cmd_cur_len;
-    conn->incoming_cmd_cur_len += (int)data_len;
-
-    /* We have appended a line to incoming_cmd.  Is the command done? */
-    if (last_idx == 0 && *conn->incoming_cmd != '+')
-      /* One line command, didn't start with '+'. */
-      break;
-    /* XXXX this code duplication is kind of dumb. */
-    if (last_idx+3 == conn->incoming_cmd_cur_len &&
-        tor_memeq(conn->incoming_cmd + last_idx, ".\r\n", 3)) {
-      /* Just appended ".\r\n"; we're done. Remove it. */
-      conn->incoming_cmd[last_idx] = '\0';
-      conn->incoming_cmd_cur_len -= 3;
-      break;
-    } else if (last_idx+2 == conn->incoming_cmd_cur_len &&
-               tor_memeq(conn->incoming_cmd + last_idx, ".\n", 2)) {
-      /* Just appended ".\n"; we're done. Remove it. */
-      conn->incoming_cmd[last_idx] = '\0';
-      conn->incoming_cmd_cur_len -= 2;
-      break;
-    }
-    /* Otherwise, read another line. */
-  }
-  data_len = conn->incoming_cmd_cur_len;
-  /* Okay, we now have a command sitting on conn->incoming_cmd. See if we
-   * recognize it.
-   */
-  cmd_len = 0;
-  while ((size_t)cmd_len < data_len
-         && !TOR_ISSPACE(conn->incoming_cmd[cmd_len]))
-    ++cmd_len;
-
-  conn->incoming_cmd[cmd_len]='\0';
-  args = conn->incoming_cmd+cmd_len+1;
-  tor_assert(data_len>(size_t)cmd_len);
-  data_len -= (cmd_len+1); /* skip the command and NUL we added after it */
-  while (TOR_ISSPACE(*args)) {
-    ++args;
-    --data_len;
-  }
-
-  /* If the connection is already closing, ignore further commands */
-  if (TO_CONN(conn)->marked_for_close) {
-    return 0;
-  }
-
-  /* Otherwise, Quit is always valid. */
-  if (!strcasecmp(conn->incoming_cmd, "QUIT")) {
-    connection_write_str_to_buf("250 closing connection\r\n", conn);
-    connection_mark_and_flush(TO_CONN(conn));
-    return 0;
-  }
-
-  if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH &&
-      !is_valid_initial_command(conn, conn->incoming_cmd)) {
-    connection_write_str_to_buf("514 Authentication required.\r\n", conn);
-    connection_mark_for_close(TO_CONN(conn));
-    return 0;
-  }
-
-  if (data_len >= UINT32_MAX) {
-    connection_write_str_to_buf("500 A 4GB command? Nice try.\r\n", conn);
-    connection_mark_for_close(TO_CONN(conn));
-    return 0;
-  }
-
-  /* XXXX Why is this not implemented as a table like the GETINFO
-   * items are?  Even handling the plus signs at the beginnings of
-   * commands wouldn't be very hard with proper macros. */
-  cmd_data_len = (uint32_t)data_len;
-  if (!strcasecmp(conn->incoming_cmd, "SETCONF")) {
-    if (handle_control_setconf(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "RESETCONF")) {
-    if (handle_control_resetconf(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "GETCONF")) {
-    if (handle_control_getconf(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "+LOADCONF")) {
-    if (handle_control_loadconf(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "SETEVENTS")) {
-    if (handle_control_setevents(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "AUTHENTICATE")) {
-    if (handle_control_authenticate(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "SAVECONF")) {
-    if (handle_control_saveconf(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "SIGNAL")) {
-    if (handle_control_signal(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "TAKEOWNERSHIP")) {
-    if (handle_control_takeownership(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "DROPOWNERSHIP")) {
-    if (handle_control_dropownership(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "MAPADDRESS")) {
-    if (handle_control_mapaddress(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "GETINFO")) {
-    if (handle_control_getinfo(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "EXTENDCIRCUIT")) {
-    if (handle_control_extendcircuit(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "SETCIRCUITPURPOSE")) {
-    if (handle_control_setcircuitpurpose(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "SETROUTERPURPOSE")) {
-    connection_write_str_to_buf("511 SETROUTERPURPOSE is obsolete.\r\n", conn);
-  } else if (!strcasecmp(conn->incoming_cmd, "ATTACHSTREAM")) {
-    if (handle_control_attachstream(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "+POSTDESCRIPTOR")) {
-    if (handle_control_postdescriptor(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "REDIRECTSTREAM")) {
-    if (handle_control_redirectstream(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "CLOSESTREAM")) {
-    if (handle_control_closestream(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "CLOSECIRCUIT")) {
-    if (handle_control_closecircuit(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "USEFEATURE")) {
-    if (handle_control_usefeature(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "RESOLVE")) {
-    if (handle_control_resolve(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "PROTOCOLINFO")) {
-    if (handle_control_protocolinfo(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "AUTHCHALLENGE")) {
-    if (handle_control_authchallenge(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "DROPGUARDS")) {
-    if (handle_control_dropguards(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "HSFETCH")) {
-    if (handle_control_hsfetch(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "+HSPOST")) {
-    if (handle_control_hspost(conn, cmd_data_len, args))
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "ADD_ONION")) {
-    int ret = handle_control_add_onion(conn, cmd_data_len, args);
-    memwipe(args, 0, cmd_data_len); /* Scrub the private key. */
-    if (ret)
-      return -1;
-  } else if (!strcasecmp(conn->incoming_cmd, "DEL_ONION")) {
-    int ret = handle_control_del_onion(conn, cmd_data_len, args);
-    memwipe(args, 0, cmd_data_len); /* Scrub the service id/pk. */
-    if (ret)
-      return -1;
-  } else {
-    connection_printf_to_buf(conn, "510 Unrecognized command \"%s\"\r\n",
-                             conn->incoming_cmd);
-  }
-
-  conn->incoming_cmd_cur_len = 0;
-  goto again;
-}
-
-/** Something major has happened to circuit <b>circ</b>: tell any
- * interested control connections. */
-int
-control_event_circuit_status(origin_circuit_t *circ, circuit_status_event_t tp,
-                             int reason_code)
-{
-  const char *status;
-  char reasons[64] = "";
-
-  if (!EVENT_IS_INTERESTING(EVENT_CIRCUIT_STATUS))
-    return 0;
-  tor_assert(circ);
-
-  switch (tp)
-    {
-    case CIRC_EVENT_LAUNCHED: status = "LAUNCHED"; break;
-    case CIRC_EVENT_BUILT: status = "BUILT"; break;
-    case CIRC_EVENT_EXTENDED: status = "EXTENDED"; break;
-    case CIRC_EVENT_FAILED: status = "FAILED"; break;
-    case CIRC_EVENT_CLOSED: status = "CLOSED"; break;
-    default:
-      log_warn(LD_BUG, "Unrecognized status code %d", (int)tp);
-      tor_fragile_assert();
-      return 0;
-    }
-
-  if (tp == CIRC_EVENT_FAILED || tp == CIRC_EVENT_CLOSED) {
-    const char *reason_str = circuit_end_reason_to_control_string(reason_code);
-    char unk_reason_buf[16];
-    if (!reason_str) {
-      tor_snprintf(unk_reason_buf, 16, "UNKNOWN_%d", reason_code);
-      reason_str = unk_reason_buf;
-    }
-    if (reason_code > 0 && reason_code & END_CIRC_REASON_FLAG_REMOTE) {
-      tor_snprintf(reasons, sizeof(reasons),
-                   " REASON=DESTROYED REMOTE_REASON=%s", reason_str);
-    } else {
-      tor_snprintf(reasons, sizeof(reasons),
-                   " REASON=%s", reason_str);
-    }
-  }
-
-  {
-    char *circdesc = circuit_describe_status_for_controller(circ);
-    const char *sp = strlen(circdesc) ? " " : "";
-    send_control_event(EVENT_CIRCUIT_STATUS,
-                                "650 CIRC %lu %s%s%s%s\r\n",
-                                (unsigned long)circ->global_identifier,
-                                status, sp,
-                                circdesc,
-                                reasons);
-    tor_free(circdesc);
-  }
-
-  return 0;
-}
-
-/** Something minor has happened to circuit <b>circ</b>: tell any
- * interested control connections. */
-static int
-control_event_circuit_status_minor(origin_circuit_t *circ,
-                                   circuit_status_minor_event_t e,
-                                   int purpose, const struct timeval *tv)
-{
-  const char *event_desc;
-  char event_tail[160] = "";
-  if (!EVENT_IS_INTERESTING(EVENT_CIRCUIT_STATUS_MINOR))
-    return 0;
-  tor_assert(circ);
-
-  switch (e)
-    {
-    case CIRC_MINOR_EVENT_PURPOSE_CHANGED:
-      event_desc = "PURPOSE_CHANGED";
-
-      {
-        /* event_tail can currently be up to 68 chars long */
-        const char *hs_state_str =
-          circuit_purpose_to_controller_hs_state_string(purpose);
-        tor_snprintf(event_tail, sizeof(event_tail),
-                     " OLD_PURPOSE=%s%s%s",
-                     circuit_purpose_to_controller_string(purpose),
-                     (hs_state_str != NULL) ? " OLD_HS_STATE=" : "",
-                     (hs_state_str != NULL) ? hs_state_str : "");
-      }
-
-      break;
-    case CIRC_MINOR_EVENT_CANNIBALIZED:
-      event_desc = "CANNIBALIZED";
-
-      {
-        /* event_tail can currently be up to 130 chars long */
-        const char *hs_state_str =
-          circuit_purpose_to_controller_hs_state_string(purpose);
-        const struct timeval *old_timestamp_began = tv;
-        char tbuf[ISO_TIME_USEC_LEN+1];
-        format_iso_time_nospace_usec(tbuf, old_timestamp_began);
-
-        tor_snprintf(event_tail, sizeof(event_tail),
-                     " OLD_PURPOSE=%s%s%s OLD_TIME_CREATED=%s",
-                     circuit_purpose_to_controller_string(purpose),
-                     (hs_state_str != NULL) ? " OLD_HS_STATE=" : "",
-                     (hs_state_str != NULL) ? hs_state_str : "",
-                     tbuf);
-      }
-
-      break;
-    default:
-      log_warn(LD_BUG, "Unrecognized status code %d", (int)e);
-      tor_fragile_assert();
-      return 0;
-    }
-
-  {
-    char *circdesc = circuit_describe_status_for_controller(circ);
-    const char *sp = strlen(circdesc) ? " " : "";
-    send_control_event(EVENT_CIRCUIT_STATUS_MINOR,
-                       "650 CIRC_MINOR %lu %s%s%s%s\r\n",
-                       (unsigned long)circ->global_identifier,
-                       event_desc, sp,
-                       circdesc,
-                       event_tail);
-    tor_free(circdesc);
-  }
-
-  return 0;
-}
-
-/**
- * <b>circ</b> has changed its purpose from <b>old_purpose</b>: tell any
- * interested controllers.
- */
-int
-control_event_circuit_purpose_changed(origin_circuit_t *circ,
-                                      int old_purpose)
-{
-  return control_event_circuit_status_minor(circ,
-                                            CIRC_MINOR_EVENT_PURPOSE_CHANGED,
-                                            old_purpose,
-                                            NULL);
-}
-
-/**
- * <b>circ</b> has changed its purpose from <b>old_purpose</b>, and its
- * created-time from <b>old_tv_created</b>: tell any interested controllers.
- */
-int
-control_event_circuit_cannibalized(origin_circuit_t *circ,
-                                   int old_purpose,
-                                   const struct timeval *old_tv_created)
-{
-  return control_event_circuit_status_minor(circ,
-                                            CIRC_MINOR_EVENT_CANNIBALIZED,
-                                            old_purpose,
-                                            old_tv_created);
-}
-
-/** Given an AP connection <b>conn</b> and a <b>len</b>-character buffer
- * <b>buf</b>, determine the address:port combination requested on
- * <b>conn</b>, and write it to <b>buf</b>.  Return 0 on success, -1 on
- * failure. */
-static int
-write_stream_target_to_buf(entry_connection_t *conn, char *buf, size_t len)
-{
-  char buf2[256];
-  if (conn->chosen_exit_name)
-    if (tor_snprintf(buf2, sizeof(buf2), ".%s.exit", conn->chosen_exit_name)<0)
-      return -1;
-  if (!conn->socks_request)
-    return -1;
-  if (tor_snprintf(buf, len, "%s%s%s:%d",
-               conn->socks_request->address,
-               conn->chosen_exit_name ? buf2 : "",
-               !conn->chosen_exit_name && connection_edge_is_rendezvous_stream(
-                                     ENTRY_TO_EDGE_CONN(conn)) ? ".onion" : "",
-               conn->socks_request->port)<0)
-    return -1;
-  return 0;
-}
-
-/** Something has happened to the stream associated with AP connection
- * <b>conn</b>: tell any interested control connections. */
-int
-control_event_stream_status(entry_connection_t *conn, stream_status_event_t tp,
-                            int reason_code)
-{
-  char reason_buf[64];
-  char addrport_buf[64];
-  const char *status;
-  circuit_t *circ;
-  origin_circuit_t *origin_circ = NULL;
-  char buf[256];
-  const char *purpose = "";
-  tor_assert(conn->socks_request);
-
-  if (!EVENT_IS_INTERESTING(EVENT_STREAM_STATUS))
-    return 0;
-
-  if (tp == STREAM_EVENT_CLOSED &&
-      (reason_code & END_STREAM_REASON_FLAG_ALREADY_SENT_CLOSED))
-    return 0;
-
-  write_stream_target_to_buf(conn, buf, sizeof(buf));
-
-  reason_buf[0] = '\0';
-  switch (tp)
-    {
-    case STREAM_EVENT_SENT_CONNECT: status = "SENTCONNECT"; break;
-    case STREAM_EVENT_SENT_RESOLVE: status = "SENTRESOLVE"; break;
-    case STREAM_EVENT_SUCCEEDED: status = "SUCCEEDED"; break;
-    case STREAM_EVENT_FAILED: status = "FAILED"; break;
-    case STREAM_EVENT_CLOSED: status = "CLOSED"; break;
-    case STREAM_EVENT_NEW: status = "NEW"; break;
-    case STREAM_EVENT_NEW_RESOLVE: status = "NEWRESOLVE"; break;
-    case STREAM_EVENT_FAILED_RETRIABLE: status = "DETACHED"; break;
-    case STREAM_EVENT_REMAP: status = "REMAP"; break;
-    default:
-      log_warn(LD_BUG, "Unrecognized status code %d", (int)tp);
-      return 0;
-    }
-  if (reason_code && (tp == STREAM_EVENT_FAILED ||
-                      tp == STREAM_EVENT_CLOSED ||
-                      tp == STREAM_EVENT_FAILED_RETRIABLE)) {
-    const char *reason_str = stream_end_reason_to_control_string(reason_code);
-    char *r = NULL;
-    if (!reason_str) {
-      tor_asprintf(&r, " UNKNOWN_%d", reason_code);
-      reason_str = r;
-    }
-    if (reason_code & END_STREAM_REASON_FLAG_REMOTE)
-      tor_snprintf(reason_buf, sizeof(reason_buf),
-                   " REASON=END REMOTE_REASON=%s", reason_str);
-    else
-      tor_snprintf(reason_buf, sizeof(reason_buf),
-                   " REASON=%s", reason_str);
-    tor_free(r);
-  } else if (reason_code && tp == STREAM_EVENT_REMAP) {
-    switch (reason_code) {
-    case REMAP_STREAM_SOURCE_CACHE:
-      strlcpy(reason_buf, " SOURCE=CACHE", sizeof(reason_buf));
-      break;
-    case REMAP_STREAM_SOURCE_EXIT:
-      strlcpy(reason_buf, " SOURCE=EXIT", sizeof(reason_buf));
-      break;
-    default:
-      tor_snprintf(reason_buf, sizeof(reason_buf), " REASON=UNKNOWN_%d",
-                   reason_code);
-      /* XXX do we want SOURCE=UNKNOWN_%d above instead? -RD */
-      break;
-    }
-  }
-
-  if (tp == STREAM_EVENT_NEW || tp == STREAM_EVENT_NEW_RESOLVE) {
-    /*
-     * When the control conn is an AF_UNIX socket and we have no address,
-     * it gets set to "(Tor_internal)"; see dnsserv_launch_request() in
-     * dnsserv.c.
-     */
-    if (strcmp(ENTRY_TO_CONN(conn)->address, "(Tor_internal)") != 0) {
-      tor_snprintf(addrport_buf,sizeof(addrport_buf), " SOURCE_ADDR=%s:%d",
-                   ENTRY_TO_CONN(conn)->address, ENTRY_TO_CONN(conn)->port);
-    } else {
-      /*
-       * else leave it blank so control on AF_UNIX doesn't need to make
-       * something up.
-       */
-      addrport_buf[0] = '\0';
-    }
-  } else {
-    addrport_buf[0] = '\0';
-  }
-
-  if (tp == STREAM_EVENT_NEW_RESOLVE) {
-    purpose = " PURPOSE=DNS_REQUEST";
-  } else if (tp == STREAM_EVENT_NEW) {
-    if (conn->use_begindir) {
-      connection_t *linked = ENTRY_TO_CONN(conn)->linked_conn;
-      int linked_dir_purpose = -1;
-      if (linked && linked->type == CONN_TYPE_DIR)
-        linked_dir_purpose = linked->purpose;
-      if (DIR_PURPOSE_IS_UPLOAD(linked_dir_purpose))
-        purpose = " PURPOSE=DIR_UPLOAD";
-      else
-        purpose = " PURPOSE=DIR_FETCH";
-    } else
-      purpose = " PURPOSE=USER";
-  }
-
-  circ = circuit_get_by_edge_conn(ENTRY_TO_EDGE_CONN(conn));
-  if (circ && CIRCUIT_IS_ORIGIN(circ))
-    origin_circ = TO_ORIGIN_CIRCUIT(circ);
-  send_control_event(EVENT_STREAM_STATUS,
-                        "650 STREAM %"PRIu64" %s %lu %s%s%s%s\r\n",
-                     (ENTRY_TO_CONN(conn)->global_identifier),
-                     status,
-                        origin_circ?
-                           (unsigned long)origin_circ->global_identifier : 0ul,
-                        buf, reason_buf, addrport_buf, purpose);
-
-  /* XXX need to specify its intended exit, etc? */
-
-  return 0;
-}
-
-/** Figure out the best name for the target router of an OR connection
- * <b>conn</b>, and write it into the <b>len</b>-character buffer
- * <b>name</b>. */
-static void
-orconn_target_get_name(char *name, size_t len, or_connection_t *conn)
-{
-  const node_t *node = node_get_by_id(conn->identity_digest);
-  if (node) {
-    tor_assert(len > MAX_VERBOSE_NICKNAME_LEN);
-    node_get_verbose_nickname(node, name);
-  } else if (! tor_digest_is_zero(conn->identity_digest)) {
-    name[0] = '$';
-    base16_encode(name+1, len-1, conn->identity_digest,
-                  DIGEST_LEN);
-  } else {
-    tor_snprintf(name, len, "%s:%d",
-                 conn->base_.address, conn->base_.port);
-  }
-}
-
-/** Called when the status of an OR connection <b>conn</b> changes: tell any
- * interested control connections. <b>tp</b> is the new status for the
- * connection.  If <b>conn</b> has just closed or failed, then <b>reason</b>
- * may be the reason why.
- */
-int
-control_event_or_conn_status(or_connection_t *conn, or_conn_status_event_t tp,
-                             int reason)
-{
-  int ncircs = 0;
-  const char *status;
-  char name[128];
-  char ncircs_buf[32] = {0}; /* > 8 + log10(2^32)=10 + 2 */
-
-  if (!EVENT_IS_INTERESTING(EVENT_OR_CONN_STATUS))
-    return 0;
-
-  switch (tp)
-    {
-    case OR_CONN_EVENT_LAUNCHED: status = "LAUNCHED"; break;
-    case OR_CONN_EVENT_CONNECTED: status = "CONNECTED"; break;
-    case OR_CONN_EVENT_FAILED: status = "FAILED"; break;
-    case OR_CONN_EVENT_CLOSED: status = "CLOSED"; break;
-    case OR_CONN_EVENT_NEW: status = "NEW"; break;
-    default:
-      log_warn(LD_BUG, "Unrecognized status code %d", (int)tp);
-      return 0;
-    }
-  if (conn->chan) {
-    ncircs = circuit_count_pending_on_channel(TLS_CHAN_TO_BASE(conn->chan));
-  } else {
-    ncircs = 0;
-  }
-  ncircs += connection_or_get_num_circuits(conn);
-  if (ncircs && (tp == OR_CONN_EVENT_FAILED || tp == OR_CONN_EVENT_CLOSED)) {
-    tor_snprintf(ncircs_buf, sizeof(ncircs_buf), " NCIRCS=%d", ncircs);
-  }
-
-  orconn_target_get_name(name, sizeof(name), conn);
-  send_control_event(EVENT_OR_CONN_STATUS,
-                              "650 ORCONN %s %s%s%s%s ID=%"PRIu64"\r\n",
-                              name, status,
-                              reason ? " REASON=" : "",
-                              orconn_end_reason_to_control_string(reason),
-                              ncircs_buf,
-                              (conn->base_.global_identifier));
-
-  return 0;
-}
-
-/**
- * Print out STREAM_BW event for a single conn
- */
-int
-control_event_stream_bandwidth(edge_connection_t *edge_conn)
-{
-  struct timeval now;
-  char tbuf[ISO_TIME_USEC_LEN+1];
-  if (EVENT_IS_INTERESTING(EVENT_STREAM_BANDWIDTH_USED)) {
-    if (!edge_conn->n_read && !edge_conn->n_written)
-      return 0;
-
-    tor_gettimeofday(&now);
-    format_iso_time_nospace_usec(tbuf, &now);
-    send_control_event(EVENT_STREAM_BANDWIDTH_USED,
-                       "650 STREAM_BW %"PRIu64" %lu %lu %s\r\n",
-                       (edge_conn->base_.global_identifier),
-                       (unsigned long)edge_conn->n_read,
-                       (unsigned long)edge_conn->n_written,
-                       tbuf);
-
-    edge_conn->n_written = edge_conn->n_read = 0;
-  }
-
-  return 0;
-}
-
-/** A second or more has elapsed: tell any interested control
- * connections how much bandwidth streams have used. */
-int
-control_event_stream_bandwidth_used(void)
-{
-  if (EVENT_IS_INTERESTING(EVENT_STREAM_BANDWIDTH_USED)) {
-    smartlist_t *conns = get_connection_array();
-    edge_connection_t *edge_conn;
-    struct timeval now;
-    char tbuf[ISO_TIME_USEC_LEN+1];
-
-    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn)
-    {
-        if (conn->type != CONN_TYPE_AP)
-          continue;
-        edge_conn = TO_EDGE_CONN(conn);
-        if (!edge_conn->n_read && !edge_conn->n_written)
-          continue;
-
-        tor_gettimeofday(&now);
-        format_iso_time_nospace_usec(tbuf, &now);
-        send_control_event(EVENT_STREAM_BANDWIDTH_USED,
-                           "650 STREAM_BW %"PRIu64" %lu %lu %s\r\n",
-                           (edge_conn->base_.global_identifier),
-                           (unsigned long)edge_conn->n_read,
-                           (unsigned long)edge_conn->n_written,
-                           tbuf);
-
-        edge_conn->n_written = edge_conn->n_read = 0;
-    }
-    SMARTLIST_FOREACH_END(conn);
-  }
-
-  return 0;
-}
-
-/** A second or more has elapsed: tell any interested control connections
- * how much bandwidth origin circuits have used. */
-int
-control_event_circ_bandwidth_used(void)
-{
-  if (!EVENT_IS_INTERESTING(EVENT_CIRC_BANDWIDTH_USED))
-    return 0;
-
-  SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
-    if (!CIRCUIT_IS_ORIGIN(circ))
-      continue;
-
-    control_event_circ_bandwidth_used_for_circ(TO_ORIGIN_CIRCUIT(circ));
-  }
-  SMARTLIST_FOREACH_END(circ);
-
-  return 0;
-}
-
-/**
- * Emit a CIRC_BW event line for a specific circuit.
- *
- * This function sets the values it emits to 0, and does not emit
- * an event if there is no new data to report since the last call.
- *
- * Therefore, it may be called at any frequency.
- */
-int
-control_event_circ_bandwidth_used_for_circ(origin_circuit_t *ocirc)
-{
-  struct timeval now;
-  char tbuf[ISO_TIME_USEC_LEN+1];
-
-  tor_assert(ocirc);
-
-  if (!EVENT_IS_INTERESTING(EVENT_CIRC_BANDWIDTH_USED))
-    return 0;
-
-  /* n_read_circ_bw and n_written_circ_bw are always updated
-   * when there is any new cell on a circuit, and set to 0 after
-   * the event, below.
-   *
-   * Therefore, checking them is sufficient to determine if there
-   * is new data to report. */
-  if (!ocirc->n_read_circ_bw && !ocirc->n_written_circ_bw)
-    return 0;
-
-  tor_gettimeofday(&now);
-  format_iso_time_nospace_usec(tbuf, &now);
-  send_control_event(EVENT_CIRC_BANDWIDTH_USED,
-                     "650 CIRC_BW ID=%d READ=%lu WRITTEN=%lu TIME=%s "
-                     "DELIVERED_READ=%lu OVERHEAD_READ=%lu "
-                     "DELIVERED_WRITTEN=%lu OVERHEAD_WRITTEN=%lu\r\n",
-                     ocirc->global_identifier,
-                     (unsigned long)ocirc->n_read_circ_bw,
-                     (unsigned long)ocirc->n_written_circ_bw,
-                     tbuf,
-                     (unsigned long)ocirc->n_delivered_read_circ_bw,
-                     (unsigned long)ocirc->n_overhead_read_circ_bw,
-                     (unsigned long)ocirc->n_delivered_written_circ_bw,
-                     (unsigned long)ocirc->n_overhead_written_circ_bw);
-  ocirc->n_written_circ_bw = ocirc->n_read_circ_bw = 0;
-  ocirc->n_overhead_written_circ_bw = ocirc->n_overhead_read_circ_bw = 0;
-  ocirc->n_delivered_written_circ_bw = ocirc->n_delivered_read_circ_bw = 0;
-
-  return 0;
-}
-
-/** Print out CONN_BW event for a single OR/DIR/EXIT <b>conn</b> and reset
-  * bandwidth counters. */
-int
-control_event_conn_bandwidth(connection_t *conn)
-{
-  const char *conn_type_str;
-  if (!get_options()->TestingEnableConnBwEvent ||
-      !EVENT_IS_INTERESTING(EVENT_CONN_BW))
-    return 0;
-  if (!conn->n_read_conn_bw && !conn->n_written_conn_bw)
-    return 0;
-  switch (conn->type) {
-    case CONN_TYPE_OR:
-      conn_type_str = "OR";
-      break;
-    case CONN_TYPE_DIR:
-      conn_type_str = "DIR";
-      break;
-    case CONN_TYPE_EXIT:
-      conn_type_str = "EXIT";
-      break;
-    default:
-      return 0;
-  }
-  send_control_event(EVENT_CONN_BW,
-                     "650 CONN_BW ID=%"PRIu64" TYPE=%s "
-                     "READ=%lu WRITTEN=%lu\r\n",
-                     (conn->global_identifier),
-                     conn_type_str,
-                     (unsigned long)conn->n_read_conn_bw,
-                     (unsigned long)conn->n_written_conn_bw);
-  conn->n_written_conn_bw = conn->n_read_conn_bw = 0;
-  return 0;
-}
-
-/** A second or more has elapsed: tell any interested control
- * connections how much bandwidth connections have used. */
-int
-control_event_conn_bandwidth_used(void)
-{
-  if (get_options()->TestingEnableConnBwEvent &&
-      EVENT_IS_INTERESTING(EVENT_CONN_BW)) {
-    SMARTLIST_FOREACH(get_connection_array(), connection_t *, conn,
-                      control_event_conn_bandwidth(conn));
-  }
-  return 0;
-}
-
-/** Helper: iterate over cell statistics of <b>circ</b> and sum up added
- * cells, removed cells, and waiting times by cell command and direction.
- * Store results in <b>cell_stats</b>.  Free cell statistics of the
- * circuit afterwards. */
-void
-sum_up_cell_stats_by_command(circuit_t *circ, cell_stats_t *cell_stats)
-{
-  memset(cell_stats, 0, sizeof(cell_stats_t));
-  SMARTLIST_FOREACH_BEGIN(circ->testing_cell_stats,
-                          const testing_cell_stats_entry_t *, ent) {
-    tor_assert(ent->command <= CELL_COMMAND_MAX_);
-    if (!ent->removed && !ent->exitward) {
-      cell_stats->added_cells_appward[ent->command] += 1;
-    } else if (!ent->removed && ent->exitward) {
-      cell_stats->added_cells_exitward[ent->command] += 1;
-    } else if (!ent->exitward) {
-      cell_stats->removed_cells_appward[ent->command] += 1;
-      cell_stats->total_time_appward[ent->command] += ent->waiting_time * 10;
-    } else {
-      cell_stats->removed_cells_exitward[ent->command] += 1;
-      cell_stats->total_time_exitward[ent->command] += ent->waiting_time * 10;
-    }
-  } SMARTLIST_FOREACH_END(ent);
-  circuit_clear_testing_cell_stats(circ);
-}
-
-/** Helper: append a cell statistics string to <code>event_parts</code>,
- * prefixed with <code>key</code>=.  Statistics consist of comma-separated
- * key:value pairs with lower-case command strings as keys and cell
- * numbers or total waiting times as values.  A key:value pair is included
- * if the entry in <code>include_if_non_zero</code> is not zero, but with
- * the (possibly zero) entry from <code>number_to_include</code>.  Both
- * arrays are expected to have a length of CELL_COMMAND_MAX_ + 1.  If no
- * entry in <code>include_if_non_zero</code> is positive, no string will
- * be added to <code>event_parts</code>. */
-void
-append_cell_stats_by_command(smartlist_t *event_parts, const char *key,
-                             const uint64_t *include_if_non_zero,
-                             const uint64_t *number_to_include)
-{
-  smartlist_t *key_value_strings = smartlist_new();
-  int i;
-  for (i = 0; i <= CELL_COMMAND_MAX_; i++) {
-    if (include_if_non_zero[i] > 0) {
-      smartlist_add_asprintf(key_value_strings, "%s:%"PRIu64,
-                             cell_command_to_string(i),
-                             (number_to_include[i]));
-    }
-  }
-  if (smartlist_len(key_value_strings) > 0) {
-    char *joined = smartlist_join_strings(key_value_strings, ",", 0, NULL);
-    smartlist_add_asprintf(event_parts, "%s=%s", key, joined);
-    SMARTLIST_FOREACH(key_value_strings, char *, cp, tor_free(cp));
-    tor_free(joined);
-  }
-  smartlist_free(key_value_strings);
-}
-
-/** Helper: format <b>cell_stats</b> for <b>circ</b> for inclusion in a
- * CELL_STATS event and write result string to <b>event_string</b>. */
-void
-format_cell_stats(char **event_string, circuit_t *circ,
-                  cell_stats_t *cell_stats)
-{
-  smartlist_t *event_parts = smartlist_new();
-  if (CIRCUIT_IS_ORIGIN(circ)) {
-    origin_circuit_t *ocirc = TO_ORIGIN_CIRCUIT(circ);
-    smartlist_add_asprintf(event_parts, "ID=%lu",
-                 (unsigned long)ocirc->global_identifier);
-  } else if (TO_OR_CIRCUIT(circ)->p_chan) {
-    or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
-    smartlist_add_asprintf(event_parts, "InboundQueue=%lu",
-                 (unsigned long)or_circ->p_circ_id);
-    smartlist_add_asprintf(event_parts, "InboundConn=%"PRIu64,
-                 (or_circ->p_chan->global_identifier));
-    append_cell_stats_by_command(event_parts, "InboundAdded",
-                                 cell_stats->added_cells_appward,
-                                 cell_stats->added_cells_appward);
-    append_cell_stats_by_command(event_parts, "InboundRemoved",
-                                 cell_stats->removed_cells_appward,
-                                 cell_stats->removed_cells_appward);
-    append_cell_stats_by_command(event_parts, "InboundTime",
-                                 cell_stats->removed_cells_appward,
-                                 cell_stats->total_time_appward);
-  }
-  if (circ->n_chan) {
-    smartlist_add_asprintf(event_parts, "OutboundQueue=%lu",
-                     (unsigned long)circ->n_circ_id);
-    smartlist_add_asprintf(event_parts, "OutboundConn=%"PRIu64,
-                 (circ->n_chan->global_identifier));
-    append_cell_stats_by_command(event_parts, "OutboundAdded",
-                                 cell_stats->added_cells_exitward,
-                                 cell_stats->added_cells_exitward);
-    append_cell_stats_by_command(event_parts, "OutboundRemoved",
-                                 cell_stats->removed_cells_exitward,
-                                 cell_stats->removed_cells_exitward);
-    append_cell_stats_by_command(event_parts, "OutboundTime",
-                                 cell_stats->removed_cells_exitward,
-                                 cell_stats->total_time_exitward);
-  }
-  *event_string = smartlist_join_strings(event_parts, " ", 0, NULL);
-  SMARTLIST_FOREACH(event_parts, char *, cp, tor_free(cp));
-  smartlist_free(event_parts);
-}
-
-/** A second or more has elapsed: tell any interested control connection
- * how many cells have been processed for a given circuit. */
-int
-control_event_circuit_cell_stats(void)
-{
-  cell_stats_t *cell_stats;
-  char *event_string;
-  if (!get_options()->TestingEnableCellStatsEvent ||
-      !EVENT_IS_INTERESTING(EVENT_CELL_STATS))
-    return 0;
-  cell_stats = tor_malloc(sizeof(cell_stats_t));
-  SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
-    if (!circ->testing_cell_stats)
-      continue;
-    sum_up_cell_stats_by_command(circ, cell_stats);
-    format_cell_stats(&event_string, circ, cell_stats);
-    send_control_event(EVENT_CELL_STATS,
-                       "650 CELL_STATS %s\r\n", event_string);
-    tor_free(event_string);
-  }
-  SMARTLIST_FOREACH_END(circ);
-  tor_free(cell_stats);
-  return 0;
-}
-
-/* about 5 minutes worth. */
-#define N_BW_EVENTS_TO_CACHE 300
-/* Index into cached_bw_events to next write. */
-static int next_measurement_idx = 0;
-/* number of entries set in n_measurements */
-static int n_measurements = 0;
-static struct cached_bw_event_s {
-  uint32_t n_read;
-  uint32_t n_written;
-} cached_bw_events[N_BW_EVENTS_TO_CACHE];
-
-/** A second or more has elapsed: tell any interested control
- * connections how much bandwidth we used. */
-int
-control_event_bandwidth_used(uint32_t n_read, uint32_t n_written)
-{
-  cached_bw_events[next_measurement_idx].n_read = n_read;
-  cached_bw_events[next_measurement_idx].n_written = n_written;
-  if (++next_measurement_idx == N_BW_EVENTS_TO_CACHE)
-    next_measurement_idx = 0;
-  if (n_measurements < N_BW_EVENTS_TO_CACHE)
-    ++n_measurements;
-
-  if (EVENT_IS_INTERESTING(EVENT_BANDWIDTH_USED)) {
-    send_control_event(EVENT_BANDWIDTH_USED,
-                       "650 BW %lu %lu\r\n",
-                       (unsigned long)n_read,
-                       (unsigned long)n_written);
-  }
-
-  return 0;
-}
-
-STATIC char *
-get_bw_samples(void)
-{
-  int i;
-  int idx = (next_measurement_idx + N_BW_EVENTS_TO_CACHE - n_measurements)
-    % N_BW_EVENTS_TO_CACHE;
-  tor_assert(0 <= idx && idx < N_BW_EVENTS_TO_CACHE);
-
-  smartlist_t *elements = smartlist_new();
-
-  for (i = 0; i < n_measurements; ++i) {
-    tor_assert(0 <= idx && idx < N_BW_EVENTS_TO_CACHE);
-    const struct cached_bw_event_s *bwe = &cached_bw_events[idx];
-
-    smartlist_add_asprintf(elements, "%u,%u",
-                           (unsigned)bwe->n_read,
-                           (unsigned)bwe->n_written);
-
-    idx = (idx + 1) % N_BW_EVENTS_TO_CACHE;
-  }
-
-  char *result = smartlist_join_strings(elements, " ", 0, NULL);
-
-  SMARTLIST_FOREACH(elements, char *, cp, tor_free(cp));
-  smartlist_free(elements);
-
-  return result;
-}
-
-/** Called when we are sending a log message to the controllers: suspend
- * sending further log messages to the controllers until we're done.  Used by
- * CONN_LOG_PROTECT. */
-void
-disable_control_logging(void)
-{
-  ++disable_log_messages;
-}
-
-/** We're done sending a log message to the controllers: re-enable controller
- * logging.  Used by CONN_LOG_PROTECT. */
-void
-enable_control_logging(void)
-{
-  if (--disable_log_messages < 0)
-    tor_assert(0);
-}
-
-/** We got a log message: tell any interested control connections. */
-void
-control_event_logmsg(int severity, uint32_t domain, const char *msg)
-{
-  int event;
-
-  /* Don't even think of trying to add stuff to a buffer from a cpuworker
-   * thread. (See #25987 for plan to fix.) */
-  if (! in_main_thread())
-    return;
-
-  if (disable_log_messages)
-    return;
-
-  if (domain == LD_BUG && EVENT_IS_INTERESTING(EVENT_STATUS_GENERAL) &&
-      severity <= LOG_NOTICE) {
-    char *esc = esc_for_log(msg);
-    ++disable_log_messages;
-    control_event_general_status(severity, "BUG REASON=%s", esc);
-    --disable_log_messages;
-    tor_free(esc);
-  }
-
-  event = log_severity_to_event(severity);
-  if (event >= 0 && EVENT_IS_INTERESTING(event)) {
-    char *b = NULL;
-    const char *s;
-    if (strchr(msg, '\n')) {
-      char *cp;
-      b = tor_strdup(msg);
-      for (cp = b; *cp; ++cp)
-        if (*cp == '\r' || *cp == '\n')
-          *cp = ' ';
-    }
-    switch (severity) {
-      case LOG_DEBUG: s = "DEBUG"; break;
-      case LOG_INFO: s = "INFO"; break;
-      case LOG_NOTICE: s = "NOTICE"; break;
-      case LOG_WARN: s = "WARN"; break;
-      case LOG_ERR: s = "ERR"; break;
-      default: s = "UnknownLogSeverity"; break;
-    }
-    ++disable_log_messages;
-    send_control_event(event,  "650 %s %s\r\n", s, b?b:msg);
-    if (severity == LOG_ERR) {
-      /* Force a flush, since we may be about to die horribly */
-      queued_events_flush_all(1);
-    }
-    --disable_log_messages;
-    tor_free(b);
-  }
-}
+static int
+peek_connection_has_http_command(connection_t *conn)
+{
+  return peek_buf_has_http_command(conn->inbuf);
+}
 
 /**
- * Logging callback: called when there is a queued pending log callback.
- */
-void
-control_event_logmsg_pending(void)
-{
-  if (! in_main_thread()) {
-    /* We can't handle this case yet, since we're using a
-     * mainloop_event_t to invoke queued_events_flush_all.  We ought to
-     * use a different mechanism instead: see #25987.
-     **/
-    return;
-  }
-  tor_assert(flush_queued_events_event);
-  mainloop_event_activate(flush_queued_events_event);
-}
-
-/** Called whenever we receive new router descriptors: tell any
- * interested control connections.  <b>routers</b> is a list of
- * routerinfo_t's.
- */
-int
-control_event_descriptors_changed(smartlist_t *routers)
-{
-  char *msg;
-
-  if (!EVENT_IS_INTERESTING(EVENT_NEW_DESC))
-    return 0;
-
-  {
-    smartlist_t *names = smartlist_new();
-    char *ids;
-    SMARTLIST_FOREACH(routers, routerinfo_t *, ri, {
-        char *b = tor_malloc(MAX_VERBOSE_NICKNAME_LEN+1);
-        router_get_verbose_nickname(b, ri);
-        smartlist_add(names, b);
-      });
-    ids = smartlist_join_strings(names, " ", 0, NULL);
-    tor_asprintf(&msg, "650 NEWDESC %s\r\n", ids);
-    send_control_event_string(EVENT_NEW_DESC,  msg);
-    tor_free(ids);
-    tor_free(msg);
-    SMARTLIST_FOREACH(names, char *, cp, tor_free(cp));
-    smartlist_free(names);
-  }
-  return 0;
-}
-
-/** Called when an address mapping on <b>from</b> from changes to <b>to</b>.
- * <b>expires</b> values less than 3 are special; see connection_edge.c.  If
- * <b>error</b> is non-NULL, it is an error code describing the failure
- * mode of the mapping.
- */
-int
-control_event_address_mapped(const char *from, const char *to, time_t expires,
-                             const char *error, const int cached)
-{
-  if (!EVENT_IS_INTERESTING(EVENT_ADDRMAP))
-    return 0;
-
-  if (expires < 3 || expires == TIME_MAX)
-    send_control_event(EVENT_ADDRMAP,
-                                "650 ADDRMAP %s %s NEVER %s%s"
-                                "CACHED=\"%s\"\r\n",
-                                  from, to, error?error:"", error?" ":"",
-                                cached?"YES":"NO");
-  else {
-    char buf[ISO_TIME_LEN+1];
-    char buf2[ISO_TIME_LEN+1];
-    format_local_iso_time(buf,expires);
-    format_iso_time(buf2,expires);
-    send_control_event(EVENT_ADDRMAP,
-                                "650 ADDRMAP %s %s \"%s\""
-                                " %s%sEXPIRES=\"%s\" CACHED=\"%s\"\r\n",
-                                from, to, buf,
-                                error?error:"", error?" ":"",
-                                buf2, cached?"YES":"NO");
-  }
-
-  return 0;
-}
-
-/** Cached liveness for network liveness events and GETINFO
- */
-
-static int network_is_live = 0;
-
-static int
-get_cached_network_liveness(void)
-{
-  return network_is_live;
-}
-
-static void
-set_cached_network_liveness(int liveness)
-{
-  network_is_live = liveness;
-}
+ * Helper: take a nul-terminated command of given length, and find where the
+ * command starts and the arguments begin.  Separate them, allocate a new
+ * string in <b>current_cmd_out</b> for the command, and return a pointer
+ * to the arguments.
+ **/
+STATIC char *
+control_split_incoming_command(char *incoming_cmd,
+                               size_t *data_len,
+                               char **current_cmd_out)
+{
+  const bool is_multiline = *data_len && incoming_cmd[0] == '+';
+  size_t cmd_len = 0;
+  while (cmd_len < *data_len
+         && !TOR_ISSPACE(incoming_cmd[cmd_len]))
+    ++cmd_len;
 
-/** The network liveness has changed; this is called from circuitstats.c
- * whenever we receive a cell, or when timeout expires and we assume the
- * network is down. */
-int
-control_event_network_liveness_update(int liveness)
-{
-  if (liveness > 0) {
-    if (get_cached_network_liveness() <= 0) {
-      /* Update cached liveness */
-      set_cached_network_liveness(1);
-      log_debug(LD_CONTROL, "Sending NETWORK_LIVENESS UP");
-      send_control_event_string(EVENT_NETWORK_LIVENESS,
-                                "650 NETWORK_LIVENESS UP\r\n");
+  *current_cmd_out = tor_memdup_nulterm(incoming_cmd, cmd_len);
+  char *args = incoming_cmd+cmd_len;
+  tor_assert(*data_len>=cmd_len);
+  *data_len -= cmd_len;
+  if (is_multiline) {
+    // Only match horizontal space: any line after the first is data,
+    // not arguments.
+    while ((*args == '\t' || *args == ' ') && *data_len) {
+      ++args;
+      --*data_len;
     }
-    /* else was already live, no-op */
   } else {
-    if (get_cached_network_liveness() > 0) {
-      /* Update cached liveness */
-      set_cached_network_liveness(0);
-      log_debug(LD_CONTROL, "Sending NETWORK_LIVENESS DOWN");
-      send_control_event_string(EVENT_NETWORK_LIVENESS,
-                                "650 NETWORK_LIVENESS DOWN\r\n");
+    while (TOR_ISSPACE(*args) && *data_len) {
+      ++args;
+      --*data_len;
     }
-    /* else was already dead, no-op */
   }
 
-  return 0;
-}
-
-/** Helper function for NS-style events. Constructs and sends an event
- * of type <b>event</b> with string <b>event_string</b> out of the set of
- * networkstatuses <b>statuses</b>. Currently it is used for NS events
- * and NEWCONSENSUS events. */
-static int
-control_event_networkstatus_changed_helper(smartlist_t *statuses,
-                                           uint16_t event,
-                                           const char *event_string)
-{
-  smartlist_t *strs;
-  char *s, *esc = NULL;
-  if (!EVENT_IS_INTERESTING(event) || !smartlist_len(statuses))
-    return 0;
-
-  strs = smartlist_new();
-  smartlist_add_strdup(strs, "650+");
-  smartlist_add_strdup(strs, event_string);
-  smartlist_add_strdup(strs, "\r\n");
-  SMARTLIST_FOREACH(statuses, const routerstatus_t *, rs,
-    {
-      s = networkstatus_getinfo_helper_single(rs);
-      if (!s) continue;
-      smartlist_add(strs, s);
-    });
-
-  s = smartlist_join_strings(strs, "", 0, NULL);
-  write_escaped_data(s, strlen(s), &esc);
-  SMARTLIST_FOREACH(strs, char *, cp, tor_free(cp));
-  smartlist_free(strs);
-  tor_free(s);
-  send_control_event_string(event,  esc);
-  send_control_event_string(event,
-                            "650 OK\r\n");
-
-  tor_free(esc);
-  return 0;
-}
-
-/** Called when the routerstatus_ts <b>statuses</b> have changed: sends
- * an NS event to any controller that cares. */
-int
-control_event_networkstatus_changed(smartlist_t *statuses)
-{
-  return control_event_networkstatus_changed_helper(statuses, EVENT_NS, "NS");
+  return args;
 }
 
-/** Called when we get a new consensus networkstatus. Sends a NEWCONSENSUS
- * event consisting of an NS-style line for each relay in the consensus. */
-int
-control_event_newconsensus(const networkstatus_t *consensus)
-{
-  if (!control_event_is_interesting(EVENT_NEWCONSENSUS))
-    return 0;
-  return control_event_networkstatus_changed_helper(
-           consensus->routerstatus_list, EVENT_NEWCONSENSUS, "NEWCONSENSUS");
-}
+static const char CONTROLPORT_IS_NOT_AN_HTTP_PROXY_MSG[] =
+  "HTTP/1.0 501 Tor ControlPort is not an HTTP proxy"
+  "\r\nContent-Type: text/html; charset=iso-8859-1\r\n\r\n"
+  "<html>\n"
+  "<head>\n"
+  "<title>Tor's ControlPort is not an HTTP proxy</title>\n"
+  "</head>\n"
+  "<body>\n"
+  "<h1>Tor's ControlPort is not an HTTP proxy</h1>\n"
+  "<p>\n"
+  "It appears you have configured your web browser to use Tor's control port"
+  " as an HTTP proxy.\n"
+  "This is not correct: Tor's default SOCKS proxy port is 9050.\n"
+  "Please configure your client accordingly.\n"
+  "</p>\n"
+  "<p>\n"
+  "See <a href=\"https://www.torproject.org/documentation.html\">"
+  "https://www.torproject.org/documentation.html</a> for more "
+  "information.\n"
+  "<!-- Plus this comment, to make the body response more than 512 bytes, so "
+  "     IE will be willing to display it. Comment comment comment comment "
+  "     comment comment comment comment comment comment comment comment.-->\n"
+  "</p>\n"
+  "</body>\n"
+  "</html>\n";
 
-/** Called when we compute a new circuitbuildtimeout */
+/** Called when data has arrived on a v1 control connection: Try to fetch
+ * commands from conn->inbuf, and execute them.
+ */
 int
-control_event_buildtimeout_set(buildtimeout_set_event_t type,
-                               const char *args)
+connection_control_process_inbuf(control_connection_t *conn)
 {
-  const char *type_string = NULL;
+  size_t data_len;
+  uint32_t cmd_data_len;
+  char *args;
 
-  if (!control_event_is_interesting(EVENT_BUILDTIMEOUT_SET))
-    return 0;
+  tor_assert(conn);
+  tor_assert(conn->base_.state == CONTROL_CONN_STATE_OPEN ||
+             conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH);
 
-  switch (type) {
-    case BUILDTIMEOUT_SET_EVENT_COMPUTED:
-      type_string = "COMPUTED";
-      break;
-    case BUILDTIMEOUT_SET_EVENT_RESET:
-      type_string = "RESET";
-      break;
-    case BUILDTIMEOUT_SET_EVENT_SUSPENDED:
-      type_string = "SUSPENDED";
-      break;
-    case BUILDTIMEOUT_SET_EVENT_DISCARD:
-      type_string = "DISCARD";
-      break;
-    case BUILDTIMEOUT_SET_EVENT_RESUME:
-      type_string = "RESUME";
-      break;
-    default:
-      type_string = "UNKNOWN";
-      break;
+  if (!conn->incoming_cmd) {
+    conn->incoming_cmd = tor_malloc(1024);
+    conn->incoming_cmd_len = 1024;
+    conn->incoming_cmd_cur_len = 0;
   }
 
-  send_control_event(EVENT_BUILDTIMEOUT_SET,
-                     "650 BUILDTIMEOUT_SET %s %s\r\n",
-                     type_string, args);
-
-  return 0;
-}
-
-/** Called when a signal has been processed from signal_callback */
-int
-control_event_signal(uintptr_t signal_num)
-{
-  const char *signal_string = NULL;
+  if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH &&
+      peek_connection_has_control0_command(TO_CONN(conn))) {
+    /* Detect v0 commands and send a "no more v0" message. */
+    size_t body_len;
+    char buf[128];
+    set_uint16(buf+2, htons(0x0000)); /* type == error */
+    set_uint16(buf+4, htons(0x0001)); /* code == internal error */
+    strlcpy(buf+6, "The v0 control protocol is not supported by Tor 0.1.2.17 "
+            "and later; upgrade your controller.",
+            sizeof(buf)-6);
+    body_len = 2+strlen(buf+6)+2; /* code, msg, nul. */
+    set_uint16(buf+0, htons(body_len));
+    connection_buf_add(buf, 4+body_len, TO_CONN(conn));
 
-  if (!control_event_is_interesting(EVENT_GOT_SIGNAL))
+    connection_mark_and_flush(TO_CONN(conn));
     return 0;
-
-  switch (signal_num) {
-    case SIGHUP:
-      signal_string = "RELOAD";
-      break;
-    case SIGUSR1:
-      signal_string = "DUMP";
-      break;
-    case SIGUSR2:
-      signal_string = "DEBUG";
-      break;
-    case SIGNEWNYM:
-      signal_string = "NEWNYM";
-      break;
-    case SIGCLEARDNSCACHE:
-      signal_string = "CLEARDNSCACHE";
-      break;
-    case SIGHEARTBEAT:
-      signal_string = "HEARTBEAT";
-      break;
-    default:
-      log_warn(LD_BUG, "Unrecognized signal %lu in control_event_signal",
-               (unsigned long)signal_num);
-      return -1;
   }
 
-  send_control_event(EVENT_GOT_SIGNAL,  "650 SIGNAL %s\r\n",
-                     signal_string);
-  return 0;
-}
-
-/** Called when a single local_routerstatus_t has changed: Sends an NS event
- * to any controller that cares. */
-int
-control_event_networkstatus_changed_single(const routerstatus_t *rs)
-{
-  smartlist_t *statuses;
-  int r;
-
-  if (!EVENT_IS_INTERESTING(EVENT_NS))
+  /* If the user has the HTTP proxy port and the control port confused. */
+  if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH &&
+      peek_connection_has_http_command(TO_CONN(conn))) {
+    connection_write_str_to_buf(CONTROLPORT_IS_NOT_AN_HTTP_PROXY_MSG, conn);
+    log_notice(LD_CONTROL, "Received HTTP request on ControlPort");
+    connection_mark_and_flush(TO_CONN(conn));
     return 0;
+  }
 
-  statuses = smartlist_new();
-  smartlist_add(statuses, (void*)rs);
-  r = control_event_networkstatus_changed(statuses);
-  smartlist_free(statuses);
-  return r;
-}
+ again:
+  while (1) {
+    size_t last_idx;
+    int r;
+    /* First, fetch a line. */
+    do {
+      data_len = conn->incoming_cmd_len - conn->incoming_cmd_cur_len;
+      r = connection_buf_get_line(TO_CONN(conn),
+                              conn->incoming_cmd+conn->incoming_cmd_cur_len,
+                              &data_len);
+      if (r == 0)
+        /* Line not all here yet. Wait. */
+        return 0;
+      else if (r == -1) {
+        if (data_len + conn->incoming_cmd_cur_len > MAX_COMMAND_LINE_LENGTH) {
+          control_write_endreply(conn, 500, "Line too long.");
+          connection_stop_reading(TO_CONN(conn));
+          connection_mark_and_flush(TO_CONN(conn));
+        }
+        while (conn->incoming_cmd_len < data_len+conn->incoming_cmd_cur_len)
+          conn->incoming_cmd_len *= 2;
+        conn->incoming_cmd = tor_realloc(conn->incoming_cmd,
+                                         conn->incoming_cmd_len);
+      }
+    } while (r != 1);
 
-/** Our own router descriptor has changed; tell any controllers that care.
- */
-int
-control_event_my_descriptor_changed(void)
-{
-  send_control_event(EVENT_DESCCHANGED,  "650 DESCCHANGED\r\n");
-  return 0;
-}
+    tor_assert(data_len);
 
-/** Helper: sends a status event where <b>type</b> is one of
- * EVENT_STATUS_{GENERAL,CLIENT,SERVER}, where <b>severity</b> is one of
- * LOG_{NOTICE,WARN,ERR}, and where <b>format</b> is a printf-style format
- * string corresponding to <b>args</b>. */
-static int
-control_event_status(int type, int severity, const char *format, va_list args)
-{
-  char *user_buf = NULL;
-  char format_buf[160];
-  const char *status, *sev;
+    last_idx = conn->incoming_cmd_cur_len;
+    conn->incoming_cmd_cur_len += (int)data_len;
 
-  switch (type) {
-    case EVENT_STATUS_GENERAL:
-      status = "STATUS_GENERAL";
-      break;
-    case EVENT_STATUS_CLIENT:
-      status = "STATUS_CLIENT";
-      break;
-    case EVENT_STATUS_SERVER:
-      status = "STATUS_SERVER";
-      break;
-    default:
-      log_warn(LD_BUG, "Unrecognized status type %d", type);
-      return -1;
-  }
-  switch (severity) {
-    case LOG_NOTICE:
-      sev = "NOTICE";
+    /* We have appended a line to incoming_cmd.  Is the command done? */
+    if (last_idx == 0 && *conn->incoming_cmd != '+')
+      /* One line command, didn't start with '+'. */
       break;
-    case LOG_WARN:
-      sev = "WARN";
+    /* XXXX this code duplication is kind of dumb. */
+    if (last_idx+3 == conn->incoming_cmd_cur_len &&
+        tor_memeq(conn->incoming_cmd + last_idx, ".\r\n", 3)) {
+      /* Just appended ".\r\n"; we're done. Remove it. */
+      conn->incoming_cmd[last_idx] = '\0';
+      conn->incoming_cmd_cur_len -= 3;
       break;
-    case LOG_ERR:
-      sev = "ERR";
+    } else if (last_idx+2 == conn->incoming_cmd_cur_len &&
+               tor_memeq(conn->incoming_cmd + last_idx, ".\n", 2)) {
+      /* Just appended ".\n"; we're done. Remove it. */
+      conn->incoming_cmd[last_idx] = '\0';
+      conn->incoming_cmd_cur_len -= 2;
       break;
-    default:
-      log_warn(LD_BUG, "Unrecognized status severity %d", severity);
-      return -1;
-  }
-  if (tor_snprintf(format_buf, sizeof(format_buf), "650 %s %s",
-                   status, sev)<0) {
-    log_warn(LD_BUG, "Format string too long.");
-    return -1;
-  }
-  tor_vasprintf(&user_buf, format, args);
-
-  send_control_event(type,  "%s %s\r\n", format_buf, user_buf);
-  tor_free(user_buf);
-  return 0;
-}
-
-#define CONTROL_EVENT_STATUS_BODY(event, sev)                   \
-  int r;                                                        \
-  do {                                                          \
-    va_list ap;                                                 \
-    if (!EVENT_IS_INTERESTING(event))                           \
-      return 0;                                                 \
-                                                                \
-    va_start(ap, format);                                       \
-    r = control_event_status((event), (sev), format, ap);       \
-    va_end(ap);                                                 \
-  } while (0)
-
-/** Format and send an EVENT_STATUS_GENERAL event whose main text is obtained
- * by formatting the arguments using the printf-style <b>format</b>. */
-int
-control_event_general_status(int severity, const char *format, ...)
-{
-  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_GENERAL, severity);
-  return r;
-}
-
-/** Format and send an EVENT_STATUS_GENERAL LOG_ERR event, and flush it to the
- * controller(s) immediately. */
-int
-control_event_general_error(const char *format, ...)
-{
-  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_GENERAL, LOG_ERR);
-  /* Force a flush, since we may be about to die horribly */
-  queued_events_flush_all(1);
-  return r;
-}
-
-/** Format and send an EVENT_STATUS_CLIENT event whose main text is obtained
- * by formatting the arguments using the printf-style <b>format</b>. */
-int
-control_event_client_status(int severity, const char *format, ...)
-{
-  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_CLIENT, severity);
-  return r;
-}
-
-/** Format and send an EVENT_STATUS_CLIENT LOG_ERR event, and flush it to the
- * controller(s) immediately. */
-int
-control_event_client_error(const char *format, ...)
-{
-  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_CLIENT, LOG_ERR);
-  /* Force a flush, since we may be about to die horribly */
-  queued_events_flush_all(1);
-  return r;
-}
-
-/** Format and send an EVENT_STATUS_SERVER event whose main text is obtained
- * by formatting the arguments using the printf-style <b>format</b>. */
-int
-control_event_server_status(int severity, const char *format, ...)
-{
-  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_SERVER, severity);
-  return r;
-}
+    }
+    /* Otherwise, read another line. */
+  }
+  data_len = conn->incoming_cmd_cur_len;
 
-/** Format and send an EVENT_STATUS_SERVER LOG_ERR event, and flush it to the
- * controller(s) immediately. */
-int
-control_event_server_error(const char *format, ...)
-{
-  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_SERVER, LOG_ERR);
-  /* Force a flush, since we may be about to die horribly */
-  queued_events_flush_all(1);
-  return r;
-}
+  /* Okay, we now have a command sitting on conn->incoming_cmd. See if we
+   * recognize it.
+   */
+  tor_free(conn->current_cmd);
+  args = control_split_incoming_command(conn->incoming_cmd, &data_len,
+                                        &conn->current_cmd);
+  if (BUG(!conn->current_cmd))
+    return -1;
 
-/** Called when the status of an entry guard with the given <b>nickname</b>
- * and identity <b>digest</b> has changed to <b>status</b>: tells any
- * controllers that care. */
-int
-control_event_guard(const char *nickname, const char *digest,
-                    const char *status)
-{
-  char hbuf[HEX_DIGEST_LEN+1];
-  base16_encode(hbuf, sizeof(hbuf), digest, DIGEST_LEN);
-  if (!EVENT_IS_INTERESTING(EVENT_GUARD))
+  /* If the connection is already closing, ignore further commands */
+  if (TO_CONN(conn)->marked_for_close) {
     return 0;
-
-  {
-    char buf[MAX_VERBOSE_NICKNAME_LEN+1];
-    const node_t *node = node_get_by_id(digest);
-    if (node) {
-      node_get_verbose_nickname(node, buf);
-    } else {
-      tor_snprintf(buf, sizeof(buf), "$%s~%s", hbuf, nickname);
-    }
-    send_control_event(EVENT_GUARD,
-                       "650 GUARD ENTRY %s %s\r\n", buf, status);
   }
-  return 0;
-}
 
-/** Called when a configuration option changes. This is generally triggered
- * by SETCONF requests and RELOAD/SIGHUP signals. The <b>elements</b> is
- * a smartlist_t containing (key, value, ...) pairs in sequence.
- * <b>value</b> can be NULL. */
-int
-control_event_conf_changed(const smartlist_t *elements)
-{
-  int i;
-  char *result;
-  smartlist_t *lines;
-  if (!EVENT_IS_INTERESTING(EVENT_CONF_CHANGED) ||
-      smartlist_len(elements) == 0) {
+  /* Otherwise, Quit is always valid. */
+  if (!strcasecmp(conn->current_cmd, "QUIT")) {
+    control_write_endreply(conn, 250, "closing connection");
+    connection_mark_and_flush(TO_CONN(conn));
     return 0;
   }
-  lines = smartlist_new();
-  for (i = 0; i < smartlist_len(elements); i += 2) {
-    char *k = smartlist_get(elements, i);
-    char *v = smartlist_get(elements, i+1);
-    if (v == NULL) {
-      smartlist_add_asprintf(lines, "650-%s", k);
-    } else {
-      smartlist_add_asprintf(lines, "650-%s=%s", k, v);
-    }
+
+  if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH &&
+      !is_valid_initial_command(conn, conn->current_cmd)) {
+    control_write_endreply(conn, 514, "Authentication required.");
+    connection_mark_for_close(TO_CONN(conn));
+    return 0;
   }
-  result = smartlist_join_strings(lines, "\r\n", 0, NULL);
-  send_control_event(EVENT_CONF_CHANGED,
-    "650-CONF_CHANGED\r\n%s\r\n650 OK\r\n", result);
-  tor_free(result);
-  SMARTLIST_FOREACH(lines, char *, cp, tor_free(cp));
-  smartlist_free(lines);
-  return 0;
-}
 
-/** Helper: Return a newly allocated string containing a path to the
- * file where we store our authentication cookie. */
-char *
-get_controller_cookie_file_name(void)
-{
-  const or_options_t *options = get_options();
-  if (options->CookieAuthFile && strlen(options->CookieAuthFile)) {
-    return tor_strdup(options->CookieAuthFile);
-  } else {
-    return get_datadir_fname("control_auth_cookie");
+  if (data_len >= UINT32_MAX) {
+    control_write_endreply(conn, 500, "A 4GB command? Nice try.");
+    connection_mark_for_close(TO_CONN(conn));
+    return 0;
   }
+
+  cmd_data_len = (uint32_t)data_len;
+  if (handle_control_command(conn, cmd_data_len, args) < 0)
+    return -1;
+
+  conn->incoming_cmd_cur_len = 0;
+  goto again;
 }
 
-/* Initialize the cookie-based authentication system of the
- * ControlPort. If <b>enabled</b> is 0, then disable the cookie
- * authentication system.  */
+/** Cached liveness for network liveness events and GETINFO
+ */
+
+static int network_is_live = 0;
+
 int
-init_control_cookie_authentication(int enabled)
+get_cached_network_liveness(void)
 {
-  char *fname = NULL;
-  int retval;
-
-  if (!enabled) {
-    authentication_cookie_is_set = 0;
-    return 0;
-  }
+  return network_is_live;
+}
 
-  fname = get_controller_cookie_file_name();
-  retval = init_cookie_authentication(fname, "", /* no header */
-                                      AUTHENTICATION_COOKIE_LEN,
-                                   get_options()->CookieAuthFileGroupReadable,
-                                      &authentication_cookie,
-                                      &authentication_cookie_is_set);
-  tor_free(fname);
-  return retval;
+void
+set_cached_network_liveness(int liveness)
+{
+  network_is_live = liveness;
 }
 
 /** A copy of the process specifier of Tor's owning controller, or
@@ -7025,553 +566,12 @@ monitor_owning_controller_process(const char *process_spec)
   }
 }
 
-/** We just generated a new summary of which countries we've seen clients
- * from recently. Send a copy to the controller in case it wants to
- * display it for the user. */
-void
-control_event_clients_seen(const char *controller_str)
-{
-  send_control_event(EVENT_CLIENTS_SEEN,
-    "650 CLIENTS_SEEN %s\r\n", controller_str);
-}
-
-/** A new pluggable transport called <b>transport_name</b> was
- *  launched on <b>addr</b>:<b>port</b>. <b>mode</b> is either
- *  "server" or "client" depending on the mode of the pluggable
- *  transport.
- *  "650" SP "TRANSPORT_LAUNCHED" SP Mode SP Name SP Address SP Port
- */
-void
-control_event_transport_launched(const char *mode, const char *transport_name,
-                                 tor_addr_t *addr, uint16_t port)
-{
-  send_control_event(EVENT_TRANSPORT_LAUNCHED,
-                     "650 TRANSPORT_LAUNCHED %s %s %s %u\r\n",
-                     mode, transport_name, fmt_addr(addr), port);
-}
-
-/** A pluggable transport called <b>pt_name</b> has emitted a log message
- * found in <b>message</b> at <b>severity</b> log level. */
-void
-control_event_pt_log(const char *log)
-{
-  send_control_event(EVENT_PT_LOG,
-                     "650 PT_LOG %s\r\n",
-                     log);
-}
-
-/** A pluggable transport has emitted a STATUS message found in
- * <b>status</b>. */
-void
-control_event_pt_status(const char *status)
-{
-  send_control_event(EVENT_PT_STATUS,
-                     "650 PT_STATUS %s\r\n",
-                     status);
-}
-
-/** Convert rendezvous auth type to string for HS_DESC control events
- */
-const char *
-rend_auth_type_to_string(rend_auth_type_t auth_type)
-{
-  const char *str;
-
-  switch (auth_type) {
-    case REND_NO_AUTH:
-      str = "NO_AUTH";
-      break;
-    case REND_BASIC_AUTH:
-      str = "BASIC_AUTH";
-      break;
-    case REND_STEALTH_AUTH:
-      str = "STEALTH_AUTH";
-      break;
-    default:
-      str = "UNKNOWN";
-  }
-
-  return str;
-}
-
-/** Return a longname the node whose identity is <b>id_digest</b>. If
- * node_get_by_id() returns NULL, base 16 encoding of <b>id_digest</b> is
- * returned instead.
- *
- * This function is not thread-safe.  Each call to this function invalidates
- * previous values returned by this function.
- */
-MOCK_IMPL(const char *,
-node_describe_longname_by_id,(const char *id_digest))
-{
-  static char longname[MAX_VERBOSE_NICKNAME_LEN+1];
-  node_get_verbose_nickname_by_id(id_digest, longname);
-  return longname;
-}
-
-/** Return either the onion address if the given pointer is a non empty
- * string else the unknown string. */
-static const char *
-rend_hsaddress_str_or_unknown(const char *onion_address)
-{
-  static const char *str_unknown = "UNKNOWN";
-  const char *str_ret = str_unknown;
-
-  /* No valid pointer, unknown it is. */
-  if (!onion_address) {
-    goto end;
-  }
-  /* Empty onion address thus we don't know, unknown it is. */
-  if (onion_address[0] == '\0') {
-    goto end;
-  }
-  /* All checks are good so return the given onion address. */
-  str_ret = onion_address;
-
- end:
-  return str_ret;
-}
-
-/** send HS_DESC requested event.
- *
- * <b>rend_query</b> is used to fetch requested onion address and auth type.
- * <b>hs_dir</b> is the description of contacting hs directory.
- * <b>desc_id_base32</b> is the ID of requested hs descriptor.
- * <b>hsdir_index</b> is the HSDir fetch index value for v3, an hex string.
- */
-void
-control_event_hs_descriptor_requested(const char *onion_address,
-                                      rend_auth_type_t auth_type,
-                                      const char *id_digest,
-                                      const char *desc_id,
-                                      const char *hsdir_index)
-{
-  char *hsdir_index_field = NULL;
-
-  if (BUG(!id_digest || !desc_id)) {
-    return;
-  }
-
-  if (hsdir_index) {
-    tor_asprintf(&hsdir_index_field, " HSDIR_INDEX=%s", hsdir_index);
-  }
-
-  send_control_event(EVENT_HS_DESC,
-                     "650 HS_DESC REQUESTED %s %s %s %s%s\r\n",
-                     rend_hsaddress_str_or_unknown(onion_address),
-                     rend_auth_type_to_string(auth_type),
-                     node_describe_longname_by_id(id_digest),
-                     desc_id,
-                     hsdir_index_field ? hsdir_index_field : "");
-  tor_free(hsdir_index_field);
-}
-
-/** For an HS descriptor query <b>rend_data</b>, using the
- * <b>onion_address</b> and HSDir fingerprint <b>hsdir_fp</b>, find out
- * which descriptor ID in the query is the right one.
- *
- * Return a pointer of the binary descriptor ID found in the query's object
- * or NULL if not found. */
-static const char *
-get_desc_id_from_query(const rend_data_t *rend_data, const char *hsdir_fp)
-{
-  int replica;
-  const char *desc_id = NULL;
-  const rend_data_v2_t *rend_data_v2 = TO_REND_DATA_V2(rend_data);
-
-  /* Possible if the fetch was done using a descriptor ID. This means that
-   * the HSFETCH command was used. */
-  if (!tor_digest_is_zero(rend_data_v2->desc_id_fetch)) {
-    desc_id = rend_data_v2->desc_id_fetch;
-    goto end;
-  }
-
-  /* Without a directory fingerprint at this stage, we can't do much. */
-  if (hsdir_fp == NULL) {
-     goto end;
-  }
-
-  /* OK, we have an onion address so now let's find which descriptor ID
-   * is the one associated with the HSDir fingerprint. */
-  for (replica = 0; replica < REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS;
-       replica++) {
-    const char *digest = rend_data_get_desc_id(rend_data, replica, NULL);
-
-    SMARTLIST_FOREACH_BEGIN(rend_data->hsdirs_fp, char *, fingerprint) {
-      if (tor_memcmp(fingerprint, hsdir_fp, DIGEST_LEN) == 0) {
-        /* Found it! This descriptor ID is the right one. */
-        desc_id = digest;
-        goto end;
-      }
-    } SMARTLIST_FOREACH_END(fingerprint);
-  }
-
- end:
-  return desc_id;
-}
-
-/** send HS_DESC CREATED event when a local service generates a descriptor.
- *
- * <b>onion_address</b> is service address.
- * <b>desc_id</b> is the descriptor ID.
- * <b>replica</b> is the the descriptor replica number. If it is negative, it
- * is ignored.
- */
-void
-control_event_hs_descriptor_created(const char *onion_address,
-                                    const char *desc_id,
-                                    int replica)
-{
-  char *replica_field = NULL;
-
-  if (BUG(!onion_address || !desc_id)) {
-    return;
-  }
-
-  if (replica >= 0) {
-    tor_asprintf(&replica_field, " REPLICA=%d", replica);
-  }
-
-  send_control_event(EVENT_HS_DESC,
-                     "650 HS_DESC CREATED %s UNKNOWN UNKNOWN %s%s\r\n",
-                     onion_address, desc_id,
-                     replica_field ? replica_field : "");
-  tor_free(replica_field);
-}
-
-/** send HS_DESC upload event.
- *
- * <b>onion_address</b> is service address.
- * <b>hs_dir</b> is the description of contacting hs directory.
- * <b>desc_id</b> is the ID of requested hs descriptor.
- */
-void
-control_event_hs_descriptor_upload(const char *onion_address,
-                                   const char *id_digest,
-                                   const char *desc_id,
-                                   const char *hsdir_index)
-{
-  char *hsdir_index_field = NULL;
-
-  if (BUG(!onion_address || !id_digest || !desc_id)) {
-    return;
-  }
-
-  if (hsdir_index) {
-    tor_asprintf(&hsdir_index_field, " HSDIR_INDEX=%s", hsdir_index);
-  }
-
-  send_control_event(EVENT_HS_DESC,
-                     "650 HS_DESC UPLOAD %s UNKNOWN %s %s%s\r\n",
-                     onion_address,
-                     node_describe_longname_by_id(id_digest),
-                     desc_id,
-                     hsdir_index_field ? hsdir_index_field : "");
-  tor_free(hsdir_index_field);
-}
-
-/** send HS_DESC event after got response from hs directory.
- *
- * NOTE: this is an internal function used by following functions:
- * control_event_hsv2_descriptor_received
- * control_event_hsv2_descriptor_failed
- * control_event_hsv3_descriptor_failed
- *
- * So do not call this function directly.
- */
-static void
-event_hs_descriptor_receive_end(const char *action,
-                                const char *onion_address,
-                                const char *desc_id,
-                                rend_auth_type_t auth_type,
-                                const char *hsdir_id_digest,
-                                const char *reason)
-{
-  char *reason_field = NULL;
-
-  if (BUG(!action || !onion_address)) {
-    return;
-  }
-
-  if (reason) {
-    tor_asprintf(&reason_field, " REASON=%s", reason);
-  }
-
-  send_control_event(EVENT_HS_DESC,
-                     "650 HS_DESC %s %s %s %s%s%s\r\n",
-                     action,
-                     rend_hsaddress_str_or_unknown(onion_address),
-                     rend_auth_type_to_string(auth_type),
-                     hsdir_id_digest ?
-                        node_describe_longname_by_id(hsdir_id_digest) :
-                        "UNKNOWN",
-                     desc_id ? desc_id : "",
-                     reason_field ? reason_field : "");
-
-  tor_free(reason_field);
-}
-
-/** send HS_DESC event after got response from hs directory.
- *
- * NOTE: this is an internal function used by following functions:
- * control_event_hs_descriptor_uploaded
- * control_event_hs_descriptor_upload_failed
- *
- * So do not call this function directly.
- */
-void
-control_event_hs_descriptor_upload_end(const char *action,
-                                       const char *onion_address,
-                                       const char *id_digest,
-                                       const char *reason)
-{
-  char *reason_field = NULL;
-
-  if (BUG(!action || !id_digest)) {
-    return;
-  }
-
-  if (reason) {
-    tor_asprintf(&reason_field, " REASON=%s", reason);
-  }
-
-  send_control_event(EVENT_HS_DESC,
-                     "650 HS_DESC %s %s UNKNOWN %s%s\r\n",
-                     action,
-                     rend_hsaddress_str_or_unknown(onion_address),
-                     node_describe_longname_by_id(id_digest),
-                     reason_field ? reason_field : "");
-
-  tor_free(reason_field);
-}
-
-/** send HS_DESC RECEIVED event
- *
- * called when we successfully received a hidden service descriptor.
- */
-void
-control_event_hsv2_descriptor_received(const char *onion_address,
-                                       const rend_data_t *rend_data,
-                                       const char *hsdir_id_digest)
-{
-  char *desc_id_field = NULL;
-  const char *desc_id;
-
-  if (BUG(!rend_data || !hsdir_id_digest || !onion_address)) {
-    return;
-  }
-
-  desc_id = get_desc_id_from_query(rend_data, hsdir_id_digest);
-  if (desc_id != NULL) {
-    char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
-    /* Set the descriptor ID digest to base32 so we can send it. */
-    base32_encode(desc_id_base32, sizeof(desc_id_base32), desc_id,
-                  DIGEST_LEN);
-    /* Extra whitespace is needed before the value. */
-    tor_asprintf(&desc_id_field, " %s", desc_id_base32);
-  }
-
-  event_hs_descriptor_receive_end("RECEIVED", onion_address, desc_id_field,
-                                  TO_REND_DATA_V2(rend_data)->auth_type,
-                                  hsdir_id_digest, NULL);
-  tor_free(desc_id_field);
-}
-
-/* Send HS_DESC RECEIVED event
- *
- * Called when we successfully received a hidden service descriptor. */
-void
-control_event_hsv3_descriptor_received(const char *onion_address,
-                                       const char *desc_id,
-                                       const char *hsdir_id_digest)
-{
-  char *desc_id_field = NULL;
-
-  if (BUG(!onion_address || !desc_id || !hsdir_id_digest)) {
-    return;
-  }
-
-  /* Because DescriptorID is an optional positional value, we need to add a
-   * whitespace before in order to not be next to the HsDir value. */
-  tor_asprintf(&desc_id_field, " %s", desc_id);
-
-  event_hs_descriptor_receive_end("RECEIVED", onion_address, desc_id_field,
-                                  REND_NO_AUTH, hsdir_id_digest, NULL);
-  tor_free(desc_id_field);
-}
-
-/** send HS_DESC UPLOADED event
- *
- * called when we successfully uploaded a hidden service descriptor.
- */
-void
-control_event_hs_descriptor_uploaded(const char *id_digest,
-                                     const char *onion_address)
-{
-  if (BUG(!id_digest)) {
-    return;
-  }
-
-  control_event_hs_descriptor_upload_end("UPLOADED", onion_address,
-                                         id_digest, NULL);
-}
-
-/** Send HS_DESC event to inform controller that query <b>rend_data</b>
- * failed to retrieve hidden service descriptor from directory identified by
- * <b>id_digest</b>. If NULL, "UNKNOWN" is used. If <b>reason</b> is not NULL,
- * add it to REASON= field.
- */
-void
-control_event_hsv2_descriptor_failed(const rend_data_t *rend_data,
-                                     const char *hsdir_id_digest,
-                                     const char *reason)
-{
-  char *desc_id_field = NULL;
-  const char *desc_id;
-
-  if (BUG(!rend_data)) {
-    return;
-  }
-
-  desc_id = get_desc_id_from_query(rend_data, hsdir_id_digest);
-  if (desc_id != NULL) {
-    char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
-    /* Set the descriptor ID digest to base32 so we can send it. */
-    base32_encode(desc_id_base32, sizeof(desc_id_base32), desc_id,
-                  DIGEST_LEN);
-    /* Extra whitespace is needed before the value. */
-    tor_asprintf(&desc_id_field, " %s", desc_id_base32);
-  }
-
-  event_hs_descriptor_receive_end("FAILED", rend_data_get_address(rend_data),
-                                  desc_id_field,
-                                  TO_REND_DATA_V2(rend_data)->auth_type,
-                                  hsdir_id_digest, reason);
-  tor_free(desc_id_field);
-}
-
-/** Send HS_DESC event to inform controller that the query to
- * <b>onion_address</b> failed to retrieve hidden service descriptor
- * <b>desc_id</b> from directory identified by <b>hsdir_id_digest</b>. If
- * NULL, "UNKNOWN" is used.  If <b>reason</b> is not NULL, add it to REASON=
- * field. */
-void
-control_event_hsv3_descriptor_failed(const char *onion_address,
-                                     const char *desc_id,
-                                     const char *hsdir_id_digest,
-                                     const char *reason)
-{
-  char *desc_id_field = NULL;
-
-  if (BUG(!onion_address || !desc_id || !reason)) {
-    return;
-  }
-
-  /* Because DescriptorID is an optional positional value, we need to add a
-   * whitespace before in order to not be next to the HsDir value. */
-  tor_asprintf(&desc_id_field, " %s", desc_id);
-
-  event_hs_descriptor_receive_end("FAILED", onion_address, desc_id_field,
-                                  REND_NO_AUTH, hsdir_id_digest, reason);
-  tor_free(desc_id_field);
-}
-
-/** Send HS_DESC_CONTENT event after completion of a successful fetch
- * from hs directory. If <b>hsdir_id_digest</b> is NULL, it is replaced
- * by "UNKNOWN". If <b>content</b> is NULL, it is replaced by an empty
- * string. The  <b>onion_address</b> or <b>desc_id</b> set to NULL will
- * not trigger the control event. */
-void
-control_event_hs_descriptor_content(const char *onion_address,
-                                    const char *desc_id,
-                                    const char *hsdir_id_digest,
-                                    const char *content)
-{
-  static const char *event_name = "HS_DESC_CONTENT";
-  char *esc_content = NULL;
-
-  if (!onion_address || !desc_id) {
-    log_warn(LD_BUG, "Called with onion_address==%p, desc_id==%p, ",
-             onion_address, desc_id);
-    return;
-  }
-
-  if (content == NULL) {
-    /* Point it to empty content so it can still be escaped. */
-    content = "";
-  }
-  write_escaped_data(content, strlen(content), &esc_content);
-
-  send_control_event(EVENT_HS_DESC_CONTENT,
-                     "650+%s %s %s %s\r\n%s650 OK\r\n",
-                     event_name,
-                     rend_hsaddress_str_or_unknown(onion_address),
-                     desc_id,
-                     hsdir_id_digest ?
-                        node_describe_longname_by_id(hsdir_id_digest) :
-                        "UNKNOWN",
-                     esc_content);
-  tor_free(esc_content);
-}
-
-/** Send HS_DESC event to inform controller upload of hidden service
- * descriptor identified by <b>id_digest</b> failed. If <b>reason</b>
- * is not NULL, add it to REASON= field.
- */
-void
-control_event_hs_descriptor_upload_failed(const char *id_digest,
-                                          const char *onion_address,
-                                          const char *reason)
-{
-  if (BUG(!id_digest)) {
-    return;
-  }
-  control_event_hs_descriptor_upload_end("FAILED", onion_address,
-                                         id_digest, reason);
-}
-
 /** Free any leftover allocated memory of the control.c subsystem. */
 void
 control_free_all(void)
 {
-  smartlist_t *queued_events = NULL;
-
-  stats_prev_n_read = stats_prev_n_written = 0;
-
-  if (authentication_cookie) /* Free the auth cookie */
-    tor_free(authentication_cookie);
-  if (detached_onion_services) { /* Free the detached onion services */
-    SMARTLIST_FOREACH(detached_onion_services, char *, cp, tor_free(cp));
-    smartlist_free(detached_onion_services);
-  }
-
-  if (queued_control_events_lock) {
-    tor_mutex_acquire(queued_control_events_lock);
-    flush_queued_event_pending = 0;
-    queued_events = queued_control_events;
-    queued_control_events = NULL;
-    tor_mutex_release(queued_control_events_lock);
-  }
-  if (queued_events) {
-    SMARTLIST_FOREACH(queued_events, queued_event_t *, ev,
-                      queued_event_free(ev));
-    smartlist_free(queued_events);
-  }
-  if (flush_queued_events_event) {
-    mainloop_event_free(flush_queued_events_event);
-    flush_queued_events_event = NULL;
-  }
+  control_auth_free_all();
+  control_events_free_all();
+  control_cmd_free_all();
   control_event_bootstrap_reset();
-  authentication_cookie_is_set = 0;
-  global_event_mask = 0;
-  disable_log_messages = 0;
-}
-
-#ifdef TOR_UNIT_TESTS
-/* For testing: change the value of global_event_mask */
-void
-control_testing_set_global_event_mask(uint64_t mask)
-{
-  global_event_mask = mask;
 }
-#endif /* defined(TOR_UNIT_TESTS) */
diff --git a/src/feature/control/control.h b/src/feature/control/control.h
index b2ab4c199..8d3595d2e 100644
--- a/src/feature/control/control.h
+++ b/src/feature/control/control.h
@@ -12,84 +12,6 @@
 #ifndef TOR_CONTROL_H
 #define TOR_CONTROL_H
 
-#include "core/or/ocirc_event.h"
-
-/** Used to indicate the type of a CIRC_MINOR event passed to the controller.
- * The various types are defined in control-spec.txt . */
-typedef enum circuit_status_minor_event_t {
-  CIRC_MINOR_EVENT_PURPOSE_CHANGED,
-  CIRC_MINOR_EVENT_CANNIBALIZED,
-} circuit_status_minor_event_t;
-
-#include "core/or/orconn_event.h"
-
-/** Used to indicate the type of a stream event passed to the controller.
- * The various types are defined in control-spec.txt */
-typedef enum stream_status_event_t {
-  STREAM_EVENT_SENT_CONNECT = 0,
-  STREAM_EVENT_SENT_RESOLVE = 1,
-  STREAM_EVENT_SUCCEEDED    = 2,
-  STREAM_EVENT_FAILED       = 3,
-  STREAM_EVENT_CLOSED       = 4,
-  STREAM_EVENT_NEW          = 5,
-  STREAM_EVENT_NEW_RESOLVE  = 6,
-  STREAM_EVENT_FAILED_RETRIABLE = 7,
-  STREAM_EVENT_REMAP        = 8
-} stream_status_event_t;
-
-/** Used to indicate the type of a buildtime event */
-typedef enum buildtimeout_set_event_t {
-  BUILDTIMEOUT_SET_EVENT_COMPUTED  = 0,
-  BUILDTIMEOUT_SET_EVENT_RESET     = 1,
-  BUILDTIMEOUT_SET_EVENT_SUSPENDED = 2,
-  BUILDTIMEOUT_SET_EVENT_DISCARD = 3,
-  BUILDTIMEOUT_SET_EVENT_RESUME = 4
-} buildtimeout_set_event_t;
-
-/** Enum describing various stages of bootstrapping, for use with controller
- * bootstrap status events. The values range from 0 to 100. */
-typedef enum {
-  BOOTSTRAP_STATUS_UNDEF=-1,
-  BOOTSTRAP_STATUS_STARTING=0,
-
-  /* Initial connection to any relay */
-
-  BOOTSTRAP_STATUS_CONN_PT=1,
-  BOOTSTRAP_STATUS_CONN_DONE_PT=2,
-  BOOTSTRAP_STATUS_CONN_PROXY=3,
-  BOOTSTRAP_STATUS_CONN_DONE_PROXY=4,
-  BOOTSTRAP_STATUS_CONN=5,
-  BOOTSTRAP_STATUS_CONN_DONE=10,
-  BOOTSTRAP_STATUS_HANDSHAKE=14,
-  BOOTSTRAP_STATUS_HANDSHAKE_DONE=15,
-
-  /* Loading directory info */
-
-  BOOTSTRAP_STATUS_ONEHOP_CREATE=20,
-  BOOTSTRAP_STATUS_REQUESTING_STATUS=25,
-  BOOTSTRAP_STATUS_LOADING_STATUS=30,
-  BOOTSTRAP_STATUS_LOADING_KEYS=40,
-  BOOTSTRAP_STATUS_REQUESTING_DESCRIPTORS=45,
-  BOOTSTRAP_STATUS_LOADING_DESCRIPTORS=50,
-  BOOTSTRAP_STATUS_ENOUGH_DIRINFO=75,
-
-  /* Connecting to a relay for AP circuits */
-
-  BOOTSTRAP_STATUS_AP_CONN_PT=76,
-  BOOTSTRAP_STATUS_AP_CONN_DONE_PT=77,
-  BOOTSTRAP_STATUS_AP_CONN_PROXY=78,
-  BOOTSTRAP_STATUS_AP_CONN_DONE_PROXY=79,
-  BOOTSTRAP_STATUS_AP_CONN=80,
-  BOOTSTRAP_STATUS_AP_CONN_DONE=85,
-  BOOTSTRAP_STATUS_AP_HANDSHAKE=89,
-  BOOTSTRAP_STATUS_AP_HANDSHAKE_DONE=90,
-
-  /* Creating AP circuits */
-
-  BOOTSTRAP_STATUS_CIRCUIT_CREATE=95,
-  BOOTSTRAP_STATUS_DONE=100
-} bootstrap_status_t;
-
 control_connection_t *TO_CONTROL_CONN(connection_t *);
 
 #define CONTROL_CONN_STATE_MIN_ 1
@@ -100,18 +22,6 @@ control_connection_t *TO_CONTROL_CONN(connection_t *);
 #define CONTROL_CONN_STATE_NEEDAUTH 2
 #define CONTROL_CONN_STATE_MAX_ 2
 
-/** Reason for remapping an AP connection's address: we have a cached
- * answer. */
-#define REMAP_STREAM_SOURCE_CACHE 1
-/** Reason for remapping an AP connection's address: the exit node told us an
- * answer. */
-#define REMAP_STREAM_SOURCE_EXIT 2
-
-void control_initialize_event_queue(void);
-
-void control_update_global_event_mask(void);
-void control_adjust_event_log_severity(void);
-
 void control_ports_write_to_file(void);
 
 /** Log information about the connection <b>conn</b>, protecting it as with
@@ -132,300 +42,28 @@ void connection_control_closed(control_connection_t *conn);
 
 int connection_control_process_inbuf(control_connection_t *conn);
 
-#define EVENT_NS 0x000F
-int control_event_is_interesting(int event);
-
-void control_per_second_events(void);
-int control_any_per_second_event_enabled(void);
-
-int control_event_circuit_status(origin_circuit_t *circ,
-                                 circuit_status_event_t e, int reason);
-int control_event_circuit_purpose_changed(origin_circuit_t *circ,
-                                          int old_purpose);
-int control_event_circuit_cannibalized(origin_circuit_t *circ,
-                                       int old_purpose,
-                                       const struct timeval *old_tv_created);
-int control_event_stream_status(entry_connection_t *conn,
-                                stream_status_event_t e,
-                                int reason);
-int control_event_or_conn_status(or_connection_t *conn,
-                                 or_conn_status_event_t e, int reason);
-int control_event_bandwidth_used(uint32_t n_read, uint32_t n_written);
-int control_event_stream_bandwidth(edge_connection_t *edge_conn);
-int control_event_stream_bandwidth_used(void);
-int control_event_circ_bandwidth_used(void);
-int control_event_circ_bandwidth_used_for_circ(origin_circuit_t *ocirc);
-int control_event_conn_bandwidth(connection_t *conn);
-int control_event_conn_bandwidth_used(void);
-int control_event_circuit_cell_stats(void);
-void control_event_logmsg(int severity, uint32_t domain, const char *msg);
-void control_event_logmsg_pending(void);
-int control_event_descriptors_changed(smartlist_t *routers);
-int control_event_address_mapped(const char *from, const char *to,
-                                 time_t expires, const char *error,
-                                 const int cached);
-int control_event_my_descriptor_changed(void);
-int control_event_network_liveness_update(int liveness);
-int control_event_networkstatus_changed(smartlist_t *statuses);
-
-int control_event_newconsensus(const networkstatus_t *consensus);
-int control_event_networkstatus_changed_single(const routerstatus_t *rs);
-int control_event_general_status(int severity, const char *format, ...)
-  CHECK_PRINTF(2,3);
-int control_event_client_status(int severity, const char *format, ...)
-  CHECK_PRINTF(2,3);
-int control_event_server_status(int severity, const char *format, ...)
-  CHECK_PRINTF(2,3);
-
-int control_event_general_error(const char *format, ...)
-  CHECK_PRINTF(1,2);
-int control_event_client_error(const char *format, ...)
-  CHECK_PRINTF(1,2);
-int control_event_server_error(const char *format, ...)
-  CHECK_PRINTF(1,2);
-
-int control_event_guard(const char *nickname, const char *digest,
-                        const char *status);
-int control_event_conf_changed(const smartlist_t *elements);
-int control_event_buildtimeout_set(buildtimeout_set_event_t type,
-                                   const char *args);
-int control_event_signal(uintptr_t signal);
-
-int init_control_cookie_authentication(int enabled);
-char *get_controller_cookie_file_name(void);
-struct config_line_t;
-smartlist_t *decode_hashed_passwords(struct config_line_t *passwords);
 void disable_control_logging(void);
 void enable_control_logging(void);
 
 void monitor_owning_controller_process(const char *process_spec);
 
-void control_event_bootstrap(bootstrap_status_t status, int progress);
-MOCK_DECL(void, control_event_bootstrap_prob_or,(const char *warn,
-                                                 int reason,
-                                                 or_connection_t *or_conn));
-void control_event_boot_dir(bootstrap_status_t status, int progress);
-void control_event_boot_first_orconn(void);
-void control_event_bootstrap_problem(const char *warn, const char *reason,
-                                     const connection_t *conn, int dowarn);
-char *control_event_boot_last_msg(void);
-void control_event_bootstrap_reset(void);
-
-void control_event_clients_seen(const char *controller_str);
-void control_event_transport_launched(const char *mode,
-                                      const char *transport_name,
-                                      tor_addr_t *addr, uint16_t port);
-void control_event_pt_log(const char *log);
-void control_event_pt_status(const char *status);
 const char *rend_auth_type_to_string(rend_auth_type_t auth_type);
-MOCK_DECL(const char *, node_describe_longname_by_id,(const char *id_digest));
-void control_event_hs_descriptor_requested(const char *onion_address,
-                                           rend_auth_type_t auth_type,
-                                           const char *id_digest,
-                                           const char *desc_id,
-                                           const char *hsdir_index);
-void control_event_hs_descriptor_created(const char *onion_address,
-                                         const char *desc_id,
-                                         int replica);
-void control_event_hs_descriptor_upload(const char *onion_address,
-                                        const char *desc_id,
-                                        const char *hs_dir,
-                                        const char *hsdir_index);
-void control_event_hs_descriptor_upload_end(const char *action,
-                                            const char *onion_address,
-                                            const char *hs_dir,
-                                            const char *reason);
-void control_event_hs_descriptor_uploaded(const char *hs_dir,
-                                          const char *onion_address);
-/* Hidden service v2 HS_DESC specific. */
-void control_event_hsv2_descriptor_failed(const rend_data_t *rend_data,
-                                          const char *id_digest,
-                                          const char *reason);
-void control_event_hsv2_descriptor_received(const char *onion_address,
-                                            const rend_data_t *rend_data,
-                                            const char *id_digest);
-/* Hidden service v3 HS_DESC specific. */
-void control_event_hsv3_descriptor_failed(const char *onion_address,
-                                          const char *desc_id,
-                                          const char *hsdir_id_digest,
-                                          const char *reason);
-void control_event_hsv3_descriptor_received(const char *onion_address,
-                                            const char *desc_id,
-                                            const char *hsdir_id_digest);
-void control_event_hs_descriptor_upload_failed(const char *hs_dir,
-                                               const char *onion_address,
-                                               const char *reason);
-void control_event_hs_descriptor_content(const char *onion_address,
-                                         const char *desc_id,
-                                         const char *hsdir_fp,
-                                         const char *content);
 void control_free_all(void);
 
-#ifdef CONTROL_PRIVATE
-#include "lib/crypt_ops/crypto_ed25519.h"
-
-/* Recognized asynchronous event types.  It's okay to expand this list
- * because it is used both as a list of v0 event types, and as indices
- * into the bitfield to determine which controllers want which events.
- */
-/* This bitfield has no event zero    0x0000 */
-#define EVENT_MIN_                    0x0001
-#define EVENT_CIRCUIT_STATUS          0x0001
-#define EVENT_STREAM_STATUS           0x0002
-#define EVENT_OR_CONN_STATUS          0x0003
-#define EVENT_BANDWIDTH_USED          0x0004
-#define EVENT_CIRCUIT_STATUS_MINOR    0x0005
-#define EVENT_NEW_DESC                0x0006
-#define EVENT_DEBUG_MSG               0x0007
-#define EVENT_INFO_MSG                0x0008
-#define EVENT_NOTICE_MSG              0x0009
-#define EVENT_WARN_MSG                0x000A
-#define EVENT_ERR_MSG                 0x000B
-#define EVENT_ADDRMAP                 0x000C
-/* There was an AUTHDIR_NEWDESCS event, but it no longer exists.  We
-   can reclaim 0x000D. */
-#define EVENT_DESCCHANGED             0x000E
-/* Exposed above */
-// #define EVENT_NS                   0x000F
-#define EVENT_STATUS_CLIENT           0x0010
-#define EVENT_STATUS_SERVER           0x0011
-#define EVENT_STATUS_GENERAL          0x0012
-#define EVENT_GUARD                   0x0013
-#define EVENT_STREAM_BANDWIDTH_USED   0x0014
-#define EVENT_CLIENTS_SEEN            0x0015
-#define EVENT_NEWCONSENSUS            0x0016
-#define EVENT_BUILDTIMEOUT_SET        0x0017
-#define EVENT_GOT_SIGNAL              0x0018
-#define EVENT_CONF_CHANGED            0x0019
-#define EVENT_CONN_BW                 0x001A
-#define EVENT_CELL_STATS              0x001B
-/* UNUSED :                           0x001C */
-#define EVENT_CIRC_BANDWIDTH_USED     0x001D
-#define EVENT_TRANSPORT_LAUNCHED      0x0020
-#define EVENT_HS_DESC                 0x0021
-#define EVENT_HS_DESC_CONTENT         0x0022
-#define EVENT_NETWORK_LIVENESS        0x0023
-#define EVENT_PT_LOG                  0x0024
-#define EVENT_PT_STATUS               0x0025
-#define EVENT_MAX_                    0x0025
-
-/* sizeof(control_connection_t.event_mask) in bits, currently a uint64_t */
-#define EVENT_CAPACITY_               0x0040
-
-/* If EVENT_MAX_ ever hits 0x0040, we need to make the mask into a
- * different structure, as it can only handle a maximum left shift of 1<<63. */
+#ifdef CONTROL_MODULE_PRIVATE
+struct signal_name_t {
+  int sig;
+  const char *signal_name;
+};
+extern const struct signal_name_t signal_table[];
+int get_cached_network_liveness(void);
+void set_cached_network_liveness(int liveness);
+#endif /* defined(CONTROL_MODULE_PRIVATE) */
 
-#if EVENT_MAX_ >= EVENT_CAPACITY_
-#error control_connection_t.event_mask has an event greater than its capacity
+#ifdef CONTROL_PRIVATE
+STATIC char *control_split_incoming_command(char *incoming_cmd,
+                                            size_t *data_len,
+                                            char **current_cmd_out);
 #endif
 
-#define EVENT_MASK_(e)               (((uint64_t)1)<<(e))
-
-#define EVENT_MASK_NONE_             ((uint64_t)0x0)
-
-#define EVENT_MASK_ABOVE_MIN_        ((~((uint64_t)0x0)) << EVENT_MIN_)
-#define EVENT_MASK_BELOW_MAX_        ((~((uint64_t)0x0)) \
-                                      >> (EVENT_CAPACITY_ - EVENT_MAX_ \
-                                          - EVENT_MIN_))
-
-#define EVENT_MASK_ALL_              (EVENT_MASK_ABOVE_MIN_ \
-                                      & EVENT_MASK_BELOW_MAX_)
-
-/* Used only by control.c and test.c */
-STATIC size_t write_escaped_data(const char *data, size_t len, char **out);
-STATIC size_t read_escaped_data(const char *data, size_t len, char **out);
-
-#ifdef TOR_UNIT_TESTS
-MOCK_DECL(STATIC void,
-          send_control_event_string,(uint16_t event, const char *msg));
-
-MOCK_DECL(STATIC void,
-          queue_control_event_string,(uint16_t event, char *msg));
-
-void control_testing_set_global_event_mask(uint64_t mask);
-#endif /* defined(TOR_UNIT_TESTS) */
-
-/** Helper structure: temporarily stores cell statistics for a circuit. */
-typedef struct cell_stats_t {
-  /** Number of cells added in app-ward direction by command. */
-  uint64_t added_cells_appward[CELL_COMMAND_MAX_ + 1];
-  /** Number of cells added in exit-ward direction by command. */
-  uint64_t added_cells_exitward[CELL_COMMAND_MAX_ + 1];
-  /** Number of cells removed in app-ward direction by command. */
-  uint64_t removed_cells_appward[CELL_COMMAND_MAX_ + 1];
-  /** Number of cells removed in exit-ward direction by command. */
-  uint64_t removed_cells_exitward[CELL_COMMAND_MAX_ + 1];
-  /** Total waiting time of cells in app-ward direction by command. */
-  uint64_t total_time_appward[CELL_COMMAND_MAX_ + 1];
-  /** Total waiting time of cells in exit-ward direction by command. */
-  uint64_t total_time_exitward[CELL_COMMAND_MAX_ + 1];
-} cell_stats_t;
-void sum_up_cell_stats_by_command(circuit_t *circ,
-                                  cell_stats_t *cell_stats);
-void append_cell_stats_by_command(smartlist_t *event_parts,
-                                  const char *key,
-                                  const uint64_t *include_if_non_zero,
-                                  const uint64_t *number_to_include);
-void format_cell_stats(char **event_string, circuit_t *circ,
-                       cell_stats_t *cell_stats);
-STATIC char *get_bw_samples(void);
-
-/* ADD_ONION secret key to create an ephemeral service. The command supports
- * multiple versions so this union stores the key and passes it to the HS
- * subsystem depending on the requested version. */
-typedef union add_onion_secret_key_t {
-  /* Hidden service v2 secret key. */
-  crypto_pk_t *v2;
-  /* Hidden service v3 secret key. */
-  ed25519_secret_key_t *v3;
-} add_onion_secret_key_t;
-
-STATIC int add_onion_helper_keyarg(const char *arg, int discard_pk,
-                                   const char **key_new_alg_out,
-                                   char **key_new_blob_out,
-                                   add_onion_secret_key_t *decoded_key,
-                                   int *hs_version, char **err_msg_out);
-
-STATIC rend_authorized_client_t *
-add_onion_helper_clientauth(const char *arg, int *created, char **err_msg_out);
-
-STATIC int getinfo_helper_onions(
-    control_connection_t *control_conn,
-    const char *question,
-    char **answer,
-    const char **errmsg);
-STATIC void getinfo_helper_downloads_networkstatus(
-    const char *flavor,
-    download_status_t **dl_to_emit,
-    const char **errmsg);
-STATIC void getinfo_helper_downloads_cert(
-    const char *fp_sk_req,
-    download_status_t **dl_to_emit,
-    smartlist_t **digest_list,
-    const char **errmsg);
-STATIC void getinfo_helper_downloads_desc(
-    const char *desc_req,
-    download_status_t **dl_to_emit,
-    smartlist_t **digest_list,
-    const char **errmsg);
-STATIC void getinfo_helper_downloads_bridge(
-    const char *bridge_req,
-    download_status_t **dl_to_emit,
-    smartlist_t **digest_list,
-    const char **errmsg);
-STATIC int getinfo_helper_downloads(
-    control_connection_t *control_conn,
-    const char *question, char **answer,
-    const char **errmsg);
-STATIC int getinfo_helper_dir(
-    control_connection_t *control_conn,
-    const char *question, char **answer,
-    const char **errmsg);
-STATIC int getinfo_helper_current_time(
-    control_connection_t *control_conn,
-    const char *question, char **answer,
-    const char **errmsg);
-
-#endif /* defined(CONTROL_PRIVATE) */
-
 #endif /* !defined(TOR_CONTROL_H) */
diff --git a/src/feature/control/control_auth.c b/src/feature/control/control_auth.c
new file mode 100644
index 000000000..49d4d415c
--- /dev/null
+++ b/src/feature/control/control_auth.c
@@ -0,0 +1,445 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_auth.c
+ * \brief Authentication for Tor's control-socket interface.
+ **/
+
+#include "core/or/or.h"
+#include "app/config/config.h"
+#include "core/mainloop/connection.h"
+#include "feature/control/control.h"
+#include "feature/control/control_cmd.h"
+#include "feature/control/control_auth.h"
+#include "feature/control/control_cmd_args_st.h"
+#include "feature/control/control_connection_st.h"
+#include "feature/control/control_proto.h"
+#include "lib/crypt_ops/crypto_rand.h"
+#include "lib/crypt_ops/crypto_util.h"
+#include "lib/encoding/confline.h"
+#include "lib/encoding/kvline.h"
+#include "lib/encoding/qstring.h"
+
+#include "lib/crypt_ops/crypto_s2k.h"
+
+/** If we're using cookie-type authentication, how long should our cookies be?
+ */
+#define AUTHENTICATION_COOKIE_LEN 32
+
+/** If true, we've set authentication_cookie to a secret code and
+ * stored it to disk. */
+static int authentication_cookie_is_set = 0;
+/** If authentication_cookie_is_set, a secret cookie that we've stored to disk
+ * and which we're using to authenticate controllers.  (If the controller can
+ * read it off disk, it has permission to connect.) */
+static uint8_t *authentication_cookie = NULL;
+
+#define SAFECOOKIE_SERVER_TO_CONTROLLER_CONSTANT \
+  "Tor safe cookie authentication server-to-controller hash"
+#define SAFECOOKIE_CONTROLLER_TO_SERVER_CONSTANT \
+  "Tor safe cookie authentication controller-to-server hash"
+#define SAFECOOKIE_SERVER_NONCE_LEN DIGEST256_LEN
+
+/** Helper: Return a newly allocated string containing a path to the
+ * file where we store our authentication cookie. */
+char *
+get_controller_cookie_file_name(void)
+{
+  const or_options_t *options = get_options();
+  if (options->CookieAuthFile && strlen(options->CookieAuthFile)) {
+    return tor_strdup(options->CookieAuthFile);
+  } else {
+    return get_datadir_fname("control_auth_cookie");
+  }
+}
+
+/* Initialize the cookie-based authentication system of the
+ * ControlPort. If <b>enabled</b> is 0, then disable the cookie
+ * authentication system.  */
+int
+init_control_cookie_authentication(int enabled)
+{
+  char *fname = NULL;
+  int retval;
+
+  if (!enabled) {
+    authentication_cookie_is_set = 0;
+    return 0;
+  }
+
+  fname = get_controller_cookie_file_name();
+  retval = init_cookie_authentication(fname, "", /* no header */
+                                      AUTHENTICATION_COOKIE_LEN,
+                                   get_options()->CookieAuthFileGroupReadable,
+                                      &authentication_cookie,
+                                      &authentication_cookie_is_set);
+  tor_free(fname);
+  return retval;
+}
+
+/** Decode the hashed, base64'd passwords stored in <b>passwords</b>.
+ * Return a smartlist of acceptable passwords (unterminated strings of
+ * length S2K_RFC2440_SPECIFIER_LEN+DIGEST_LEN) on success, or NULL on
+ * failure.
+ */
+smartlist_t *
+decode_hashed_passwords(config_line_t *passwords)
+{
+  char decoded[64];
+  config_line_t *cl;
+  smartlist_t *sl = smartlist_new();
+
+  tor_assert(passwords);
+
+  for (cl = passwords; cl; cl = cl->next) {
+    const char *hashed = cl->value;
+
+    if (!strcmpstart(hashed, "16:")) {
+      if (base16_decode(decoded, sizeof(decoded), hashed+3, strlen(hashed+3))
+                        != S2K_RFC2440_SPECIFIER_LEN + DIGEST_LEN
+          || strlen(hashed+3) != (S2K_RFC2440_SPECIFIER_LEN+DIGEST_LEN)*2) {
+        goto err;
+      }
+    } else {
+        if (base64_decode(decoded, sizeof(decoded), hashed, strlen(hashed))
+            != S2K_RFC2440_SPECIFIER_LEN+DIGEST_LEN) {
+          goto err;
+        }
+    }
+    smartlist_add(sl,
+                  tor_memdup(decoded, S2K_RFC2440_SPECIFIER_LEN+DIGEST_LEN));
+  }
+
+  return sl;
+
+ err:
+  SMARTLIST_FOREACH(sl, char*, cp, tor_free(cp));
+  smartlist_free(sl);
+  return NULL;
+}
+
+const control_cmd_syntax_t authchallenge_syntax = {
+   .min_args = 1,
+   .max_args = 1,
+   .accept_keywords=true,
+   .kvline_flags=KV_OMIT_KEYS|KV_QUOTED_QSTRING,
+   .store_raw_body=true
+};
+
+/** Called when we get an AUTHCHALLENGE command. */
+int
+handle_control_authchallenge(control_connection_t *conn,
+                             const control_cmd_args_t *args)
+{
+  char *client_nonce;
+  size_t client_nonce_len;
+  char server_hash[DIGEST256_LEN];
+  char server_hash_encoded[HEX_DIGEST256_LEN+1];
+  char server_nonce[SAFECOOKIE_SERVER_NONCE_LEN];
+  char server_nonce_encoded[(2*SAFECOOKIE_SERVER_NONCE_LEN) + 1];
+
+  if (strcasecmp(smartlist_get(args->args, 0), "SAFECOOKIE")) {
+    control_write_endreply(conn, 513,
+                           "AUTHCHALLENGE only supports SAFECOOKIE "
+                           "authentication");
+    goto fail;
+  }
+  if (!authentication_cookie_is_set) {
+    control_write_endreply(conn, 515, "Cookie authentication is disabled");
+    goto fail;
+  }
+  if (args->kwargs == NULL || args->kwargs->next != NULL) {
+    /*    connection_write_str_to_buf("512 AUTHCHALLENGE requires exactly "
+                                "2 arguments.\r\n", conn);
+    */
+    control_printf_endreply(conn, 512,
+                            "AUTHCHALLENGE dislikes argument list %s",
+                            escaped(args->raw_body));
+    goto fail;
+  }
+  if (strcmp(args->kwargs->key, "")) {
+    control_write_endreply(conn, 512,
+                           "AUTHCHALLENGE does not accept keyword "
+                           "arguments.");
+    goto fail;
+  }
+
+  bool contains_quote = strchr(args->raw_body, '\"');
+  if (contains_quote) {
+    /* The nonce was quoted */
+    client_nonce = tor_strdup(args->kwargs->value);
+    client_nonce_len = strlen(client_nonce);
+  } else {
+    /* The nonce was should be in hex. */
+    const char *hex_nonce = args->kwargs->value;
+    client_nonce_len = strlen(hex_nonce) / 2;
+    client_nonce = tor_malloc(client_nonce_len);
+    if (base16_decode(client_nonce, client_nonce_len, hex_nonce,
+                      strlen(hex_nonce)) != (int)client_nonce_len) {
+      control_write_endreply(conn, 513, "Invalid base16 client nonce");
+      tor_free(client_nonce);
+      goto fail;
+    }
+  }
+
+  crypto_rand(server_nonce, SAFECOOKIE_SERVER_NONCE_LEN);
+
+  /* Now compute and send the server-to-controller response, and the
+   * server's nonce. */
+  tor_assert(authentication_cookie != NULL);
+
+  {
+    size_t tmp_len = (AUTHENTICATION_COOKIE_LEN +
+                      client_nonce_len +
+                      SAFECOOKIE_SERVER_NONCE_LEN);
+    char *tmp = tor_malloc_zero(tmp_len);
+    char *client_hash = tor_malloc_zero(DIGEST256_LEN);
+    memcpy(tmp, authentication_cookie, AUTHENTICATION_COOKIE_LEN);
+    memcpy(tmp + AUTHENTICATION_COOKIE_LEN, client_nonce, client_nonce_len);
+    memcpy(tmp + AUTHENTICATION_COOKIE_LEN + client_nonce_len,
+           server_nonce, SAFECOOKIE_SERVER_NONCE_LEN);
+
+    crypto_hmac_sha256(server_hash,
+                       SAFECOOKIE_SERVER_TO_CONTROLLER_CONSTANT,
+                       strlen(SAFECOOKIE_SERVER_TO_CONTROLLER_CONSTANT),
+                       tmp,
+                       tmp_len);
+
+    crypto_hmac_sha256(client_hash,
+                       SAFECOOKIE_CONTROLLER_TO_SERVER_CONSTANT,
+                       strlen(SAFECOOKIE_CONTROLLER_TO_SERVER_CONSTANT),
+                       tmp,
+                       tmp_len);
+
+    conn->safecookie_client_hash = client_hash;
+
+    tor_free(tmp);
+  }
+
+  base16_encode(server_hash_encoded, sizeof(server_hash_encoded),
+                server_hash, sizeof(server_hash));
+  base16_encode(server_nonce_encoded, sizeof(server_nonce_encoded),
+                server_nonce, sizeof(server_nonce));
+
+  control_printf_endreply(conn, 250,
+                          "AUTHCHALLENGE SERVERHASH=%s SERVERNONCE=%s",
+                          server_hash_encoded,
+                          server_nonce_encoded);
+
+  tor_free(client_nonce);
+  return 0;
+ fail:
+  connection_mark_for_close(TO_CONN(conn));
+  return -1;
+}
+
+const control_cmd_syntax_t authenticate_syntax = {
+   .max_args = 0,
+   .accept_keywords=true,
+   .kvline_flags=KV_OMIT_KEYS|KV_QUOTED_QSTRING,
+   .store_raw_body=true
+};
+
+/** Called when we get an AUTHENTICATE message.  Check whether the
+ * authentication is valid, and if so, update the connection's state to
+ * OPEN.  Reply with DONE or ERROR.
+ */
+int
+handle_control_authenticate(control_connection_t *conn,
+                            const control_cmd_args_t *args)
+{
+  bool used_quoted_string = false;
+  const or_options_t *options = get_options();
+  const char *errstr = "Unknown error";
+  char *password;
+  size_t password_len;
+  int bad_cookie=0, bad_password=0;
+  smartlist_t *sl = NULL;
+
+  if (args->kwargs == NULL) {
+    password = tor_strdup("");
+    password_len = 0;
+  } else if (args->kwargs->next) {
+    control_write_endreply(conn, 512, "Too many arguments to AUTHENTICATE.");
+    connection_mark_for_close(TO_CONN(conn));
+    return 0;
+  } else if (strcmp(args->kwargs->key, "")) {
+    control_write_endreply(conn, 512,
+                           "AUTHENTICATE does not accept keyword arguments.");
+    connection_mark_for_close(TO_CONN(conn));
+    return 0;
+  } else if (strchr(args->raw_body, '\"')) {
+    used_quoted_string = true;
+    password = tor_strdup(args->kwargs->value);
+    password_len = strlen(password);
+  } else {
+    const char *hex_passwd = args->kwargs->value;
+    password_len = strlen(hex_passwd) / 2;
+    password = tor_malloc(password_len+1);
+    if (base16_decode(password, password_len+1, hex_passwd, strlen(hex_passwd))
+                      != (int) password_len) {
+      control_write_endreply(conn, 551,
+            "Invalid hexadecimal encoding.  Maybe you tried a plain text "
+            "password?  If so, the standard requires that you put it in "
+            "double quotes.");
+      connection_mark_for_close(TO_CONN(conn));
+      tor_free(password);
+      return 0;
+    }
+  }
+
+  if (conn->safecookie_client_hash != NULL) {
+    /* The controller has chosen safe cookie authentication; the only
+     * acceptable authentication value is the controller-to-server
+     * response. */
+
+    tor_assert(authentication_cookie_is_set);
+
+    if (password_len != DIGEST256_LEN) {
+      log_warn(LD_CONTROL,
+               "Got safe cookie authentication response with wrong length "
+               "(%d)", (int)password_len);
+      errstr = "Wrong length for safe cookie response.";
+      goto err;
+    }
+
+    if (tor_memneq(conn->safecookie_client_hash, password, DIGEST256_LEN)) {
+      log_warn(LD_CONTROL,
+               "Got incorrect safe cookie authentication response");
+      errstr = "Safe cookie response did not match expected value.";
+      goto err;
+    }
+
+    tor_free(conn->safecookie_client_hash);
+    goto ok;
+  }
+
+  if (!options->CookieAuthentication && !options->HashedControlPassword &&
+      !options->HashedControlSessionPassword) {
+    /* if Tor doesn't demand any stronger authentication, then
+     * the controller can get in with anything. */
+    goto ok;
+  }
+
+  if (options->CookieAuthentication) {
+    int also_password = options->HashedControlPassword != NULL ||
+      options->HashedControlSessionPassword != NULL;
+    if (password_len != AUTHENTICATION_COOKIE_LEN) {
+      if (!also_password) {
+        log_warn(LD_CONTROL, "Got authentication cookie with wrong length "
+                 "(%d)", (int)password_len);
+        errstr = "Wrong length on authentication cookie.";
+        goto err;
+      }
+      bad_cookie = 1;
+    } else if (tor_memneq(authentication_cookie, password, password_len)) {
+      if (!also_password) {
+        log_warn(LD_CONTROL, "Got mismatched authentication cookie");
+        errstr = "Authentication cookie did not match expected value.";
+        goto err;
+      }
+      bad_cookie = 1;
+    } else {
+      goto ok;
+    }
+  }
+
+  if (options->HashedControlPassword ||
+      options->HashedControlSessionPassword) {
+    int bad = 0;
+    smartlist_t *sl_tmp;
+    char received[DIGEST_LEN];
+    int also_cookie = options->CookieAuthentication;
+    sl = smartlist_new();
+    if (options->HashedControlPassword) {
+      sl_tmp = decode_hashed_passwords(options->HashedControlPassword);
+      if (!sl_tmp)
+        bad = 1;
+      else {
+        smartlist_add_all(sl, sl_tmp);
+        smartlist_free(sl_tmp);
+      }
+    }
+    if (options->HashedControlSessionPassword) {
+      sl_tmp = decode_hashed_passwords(options->HashedControlSessionPassword);
+      if (!sl_tmp)
+        bad = 1;
+      else {
+        smartlist_add_all(sl, sl_tmp);
+        smartlist_free(sl_tmp);
+      }
+    }
+    if (bad) {
+      if (!also_cookie) {
+        log_warn(LD_BUG,
+                 "Couldn't decode HashedControlPassword: invalid base16");
+        errstr="Couldn't decode HashedControlPassword value in configuration.";
+        goto err;
+      }
+      bad_password = 1;
+      SMARTLIST_FOREACH(sl, char *, str, tor_free(str));
+      smartlist_free(sl);
+      sl = NULL;
+    } else {
+      SMARTLIST_FOREACH(sl, char *, expected,
+      {
+        secret_to_key_rfc2440(received,DIGEST_LEN,
+                              password,password_len,expected);
+        if (tor_memeq(expected + S2K_RFC2440_SPECIFIER_LEN,
+                      received, DIGEST_LEN))
+          goto ok;
+      });
+      SMARTLIST_FOREACH(sl, char *, str, tor_free(str));
+      smartlist_free(sl);
+      sl = NULL;
+
+      if (used_quoted_string)
+        errstr = "Password did not match HashedControlPassword value from "
+          "configuration";
+      else
+        errstr = "Password did not match HashedControlPassword value from "
+          "configuration. Maybe you tried a plain text password? "
+          "If so, the standard requires that you put it in double quotes.";
+      bad_password = 1;
+      if (!also_cookie)
+        goto err;
+    }
+  }
+
+  /** We only get here if both kinds of authentication failed. */
+  tor_assert(bad_password && bad_cookie);
+  log_warn(LD_CONTROL, "Bad password or authentication cookie on controller.");
+  errstr = "Password did not match HashedControlPassword *or* authentication "
+    "cookie.";
+
+ err:
+  tor_free(password);
+  control_printf_endreply(conn, 515, "Authentication failed: %s", errstr);
+  connection_mark_for_close(TO_CONN(conn));
+  if (sl) { /* clean up */
+    SMARTLIST_FOREACH(sl, char *, str, tor_free(str));
+    smartlist_free(sl);
+  }
+  return 0;
+ ok:
+  log_info(LD_CONTROL, "Authenticated control connection ("TOR_SOCKET_T_FORMAT
+           ")", conn->base_.s);
+  send_control_done(conn);
+  conn->base_.state = CONTROL_CONN_STATE_OPEN;
+  tor_free(password);
+  if (sl) { /* clean up */
+    SMARTLIST_FOREACH(sl, char *, str, tor_free(str));
+    smartlist_free(sl);
+  }
+  return 0;
+}
+
+void
+control_auth_free_all(void)
+{
+  if (authentication_cookie) /* Free the auth cookie */
+    tor_free(authentication_cookie);
+  authentication_cookie_is_set = 0;
+}
diff --git a/src/feature/control/control_auth.h b/src/feature/control/control_auth.h
new file mode 100644
index 000000000..246e18ccb
--- /dev/null
+++ b/src/feature/control/control_auth.h
@@ -0,0 +1,32 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_auth.h
+ * \brief Header file for control_auth.c.
+ **/
+
+#ifndef TOR_CONTROL_AUTH_H
+#define TOR_CONTROL_AUTH_H
+
+struct control_cmd_args_t;
+struct control_cmd_syntax_t;
+
+int init_control_cookie_authentication(int enabled);
+char *get_controller_cookie_file_name(void);
+struct config_line_t;
+smartlist_t *decode_hashed_passwords(struct config_line_t *passwords);
+
+int handle_control_authchallenge(control_connection_t *conn,
+                                 const struct control_cmd_args_t *args);
+int handle_control_authenticate(control_connection_t *conn,
+                                const struct control_cmd_args_t *args);
+void control_auth_free_all(void);
+
+extern const struct control_cmd_syntax_t authchallenge_syntax;
+extern const struct control_cmd_syntax_t authenticate_syntax;
+
+#endif /* !defined(TOR_CONTROL_AUTH_H) */
diff --git a/src/feature/control/control_bootstrap.c b/src/feature/control/control_bootstrap.c
index 8153d7595..098e24682 100644
--- a/src/feature/control/control_bootstrap.c
+++ b/src/feature/control/control_bootstrap.c
@@ -14,7 +14,7 @@
 #include "core/or/connection_st.h"
 #include "core/or/or_connection_st.h"
 #include "core/or/reasons.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/hibernate/hibernate.h"
 #include "lib/malloc/malloc.h"
 
diff --git a/src/feature/control/control_cmd.c b/src/feature/control/control_cmd.c
new file mode 100644
index 000000000..abb579bd4
--- /dev/null
+++ b/src/feature/control/control_cmd.c
@@ -0,0 +1,2408 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_cmd.c
+ * \brief Implement various commands for Tor's control-socket interface.
+ **/
+
+#define CONTROL_MODULE_PRIVATE
+#define CONTROL_CMD_PRIVATE
+#define CONTROL_EVENTS_PRIVATE
+
+#include "core/or/or.h"
+#include "app/config/config.h"
+#include "app/config/confparse.h"
+#include "app/main/main.h"
+#include "core/mainloop/connection.h"
+#include "core/or/circuitbuild.h"
+#include "core/or/circuitlist.h"
+#include "core/or/circuituse.h"
+#include "core/or/connection_edge.h"
+#include "feature/client/addressmap.h"
+#include "feature/client/dnsserv.h"
+#include "feature/client/entrynodes.h"
+#include "feature/control/control.h"
+#include "feature/control/control_auth.h"
+#include "feature/control/control_cmd.h"
+#include "feature/control/control_events.h"
+#include "feature/control/control_getinfo.h"
+#include "feature/control/control_proto.h"
+#include "feature/hs/hs_control.h"
+#include "feature/nodelist/nodelist.h"
+#include "feature/nodelist/routerinfo.h"
+#include "feature/nodelist/routerlist.h"
+#include "feature/rend/rendclient.h"
+#include "feature/rend/rendcommon.h"
+#include "feature/rend/rendparse.h"
+#include "feature/rend/rendservice.h"
+#include "lib/crypt_ops/crypto_rand.h"
+#include "lib/crypt_ops/crypto_util.h"
+#include "lib/encoding/confline.h"
+#include "lib/encoding/kvline.h"
+
+#include "core/or/cpath_build_state_st.h"
+#include "core/or/entry_connection_st.h"
+#include "core/or/origin_circuit_st.h"
+#include "core/or/socks_request_st.h"
+#include "feature/control/control_cmd_args_st.h"
+#include "feature/control/control_connection_st.h"
+#include "feature/nodelist/node_st.h"
+#include "feature/nodelist/routerinfo_st.h"
+#include "feature/rend/rend_authorized_client_st.h"
+#include "feature/rend/rend_encoded_v2_service_descriptor_st.h"
+#include "feature/rend/rend_service_descriptor_st.h"
+
+static int control_setconf_helper(control_connection_t *conn,
+                                  const control_cmd_args_t *args,
+                                  int use_defaults);
+
+/** Yield true iff <b>s</b> is the state of a control_connection_t that has
+ * finished authentication and is accepting commands. */
+#define STATE_IS_OPEN(s) ((s) == CONTROL_CONN_STATE_OPEN)
+
+/**
+ * Release all storage held in <b>args</b>
+ **/
+void
+control_cmd_args_free_(control_cmd_args_t *args)
+{
+  if (! args)
+    return;
+
+  if (args->args) {
+    SMARTLIST_FOREACH(args->args, char *, c, tor_free(c));
+    smartlist_free(args->args);
+  }
+  config_free_lines(args->kwargs);
+  tor_free(args->cmddata);
+
+  tor_free(args);
+}
+
+/** Erase all memory held in <b>args</b>. */
+void
+control_cmd_args_wipe(control_cmd_args_t *args)
+{
+  if (!args)
+    return;
+
+  if (args->args) {
+    SMARTLIST_FOREACH(args->args, char *, c, memwipe(c, 0, strlen(c)));
+  }
+  for (config_line_t *line = args->kwargs; line; line = line->next) {
+    memwipe(line->key, 0, strlen(line->key));
+    memwipe(line->value, 0, strlen(line->value));
+  }
+  if (args->cmddata)
+    memwipe(args->cmddata, 0, args->cmddata_len);
+}
+
+/**
+ * Return true iff any element of the NULL-terminated <b>array</b> matches
+ * <b>kwd</b>. Case-insensitive.
+ **/
+static bool
+string_array_contains_keyword(const char **array, const char *kwd)
+{
+  for (unsigned i = 0; array[i]; ++i) {
+    if (! strcasecmp(array[i], kwd))
+      return true;
+  }
+  return false;
+}
+
+/** Helper for argument parsing: check whether the keyword arguments just
+ * parsed in <b>result</b> were well-formed according to <b>syntax</b>.
+ *
+ * On success, return 0.  On failure, return -1 and set *<b>error_out</b>
+ * to a newly allocated error string.
+ **/
+static int
+kvline_check_keyword_args(const control_cmd_args_t *result,
+                          const control_cmd_syntax_t *syntax,
+                          char **error_out)
+{
+  if (result->kwargs == NULL) {
+    tor_asprintf(error_out, "Cannot parse keyword argument(s)");
+    return -1;
+  }
+
+  if (! syntax->allowed_keywords) {
+    /* All keywords are permitted. */
+    return 0;
+  }
+
+  /* Check for unpermitted arguments */
+  const config_line_t *line;
+  for (line = result->kwargs; line; line = line->next) {
+    if (! string_array_contains_keyword(syntax->allowed_keywords,
+                                        line->key)) {
+      tor_asprintf(error_out, "Unrecognized keyword argument %s",
+                   escaped(line->key));
+      return -1;
+    }
+  }
+
+  return 0;
+}
+
+/**
+ * Helper: parse the arguments to a command according to <b>syntax</b>.  On
+ * success, set *<b>error_out</b> to NULL and return a newly allocated
+ * control_cmd_args_t.  On failure, set *<b>error_out</b> to newly allocated
+ * error string, and return NULL.
+ **/
+STATIC control_cmd_args_t *
+control_cmd_parse_args(const char *command,
+                       const control_cmd_syntax_t *syntax,
+                       size_t body_len,
+                       const char *body,
+                       char **error_out)
+{
+  *error_out = NULL;
+  control_cmd_args_t *result = tor_malloc_zero(sizeof(control_cmd_args_t));
+  const char *cmdline;
+  char *cmdline_alloc = NULL;
+  tor_assert(syntax->max_args < INT_MAX || syntax->max_args == UINT_MAX);
+
+  result->command = command;
+
+  if (syntax->store_raw_body) {
+    tor_assert(body[body_len] == 0);
+    result->raw_body = body;
+  }
+
+  const char *eol = memchr(body, '\n', body_len);
+  if (syntax->want_cmddata) {
+    if (! eol || (eol+1) == body+body_len) {
+      *error_out = tor_strdup("Empty body");
+      goto err;
+    }
+    cmdline_alloc = tor_memdup_nulterm(body, eol-body);
+    cmdline = cmdline_alloc;
+    ++eol;
+    result->cmddata_len = read_escaped_data(eol, (body+body_len)-eol,
+                                           &result->cmddata);
+  } else {
+    if (eol && (eol+1) != body+body_len) {
+      *error_out = tor_strdup("Unexpected body");
+      goto err;
+    }
+    cmdline = body;
+  }
+
+  result->args = smartlist_new();
+  smartlist_split_string(result->args, cmdline, " ",
+                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK,
+                         (int)(syntax->max_args+1));
+  size_t n_args = smartlist_len(result->args);
+  if (n_args < syntax->min_args) {
+    tor_asprintf(error_out, "Need at least %u argument(s)",
+                 syntax->min_args);
+    goto err;
+  } else if (n_args > syntax->max_args && ! syntax->accept_keywords) {
+    tor_asprintf(error_out, "Cannot accept more than %u argument(s)",
+                 syntax->max_args);
+    goto err;
+  }
+
+  if (n_args > syntax->max_args) {
+    /* We have extra arguments after the positional arguments, and we didn't
+       treat them as an error, so they must count as keyword arguments: Either
+       K=V pairs, or flags, or both. */
+    tor_assert(n_args == syntax->max_args + 1);
+    tor_assert(syntax->accept_keywords);
+    char *remainder = smartlist_pop_last(result->args);
+    result->kwargs = kvline_parse(remainder, syntax->kvline_flags);
+    tor_free(remainder);
+    if (kvline_check_keyword_args(result, syntax, error_out) < 0) {
+      goto err;
+    }
+  }
+
+  tor_assert_nonfatal(*error_out == NULL);
+  goto done;
+ err:
+  tor_assert_nonfatal(*error_out != NULL);
+  control_cmd_args_free(result);
+ done:
+  tor_free(cmdline_alloc);
+  return result;
+}
+
+/**
+ * Return true iff <b>lines</b> contains <b>flags</b> as a no-value
+ * (keyword-only) entry.
+ **/
+static bool
+config_lines_contain_flag(const config_line_t *lines, const char *flag)
+{
+  const config_line_t *line = config_line_find_case(lines, flag);
+  return line && !strcmp(line->value, "");
+}
+
+static const control_cmd_syntax_t setconf_syntax = {
+  .max_args=0,
+  .accept_keywords=true,
+  .kvline_flags=KV_OMIT_VALS|KV_QUOTED,
+};
+
+/** Called when we receive a SETCONF message: parse the body and try
+ * to update our configuration.  Reply with a DONE or ERROR message.
+ * Modifies the contents of body.*/
+static int
+handle_control_setconf(control_connection_t *conn,
+                       const control_cmd_args_t *args)
+{
+  return control_setconf_helper(conn, args, 0);
+}
+
+static const control_cmd_syntax_t resetconf_syntax = {
+  .max_args=0,
+  .accept_keywords=true,
+  .kvline_flags=KV_OMIT_VALS|KV_QUOTED,
+};
+
+/** Called when we receive a RESETCONF message: parse the body and try
+ * to update our configuration.  Reply with a DONE or ERROR message.
+ * Modifies the contents of body. */
+static int
+handle_control_resetconf(control_connection_t *conn,
+                         const control_cmd_args_t *args)
+{
+  return control_setconf_helper(conn, args, 1);
+}
+
+static const control_cmd_syntax_t getconf_syntax = {
+  .max_args=UINT_MAX
+};
+
+/** Called when we receive a GETCONF message.  Parse the request, and
+ * reply with a CONFVALUE or an ERROR message */
+static int
+handle_control_getconf(control_connection_t *conn,
+                       const control_cmd_args_t *args)
+{
+  const smartlist_t *questions = args->args;
+  smartlist_t *answers = smartlist_new();
+  smartlist_t *unrecognized = smartlist_new();
+  char *msg = NULL;
+  size_t msg_len;
+  const or_options_t *options = get_options();
+  int i, len;
+
+  SMARTLIST_FOREACH_BEGIN(questions, const char *, q) {
+    if (!option_is_recognized(q)) {
+      smartlist_add(unrecognized, (char*) q);
+    } else {
+      config_line_t *answer = option_get_assignment(options,q);
+      if (!answer) {
+        const char *name = option_get_canonical_name(q);
+        smartlist_add_asprintf(answers, "250-%s\r\n", name);
+      }
+
+      while (answer) {
+        config_line_t *next;
+        smartlist_add_asprintf(answers, "250-%s=%s\r\n",
+                     answer->key, answer->value);
+
+        next = answer->next;
+        tor_free(answer->key);
+        tor_free(answer->value);
+        tor_free(answer);
+        answer = next;
+      }
+    }
+  } SMARTLIST_FOREACH_END(q);
+
+  if ((len = smartlist_len(unrecognized))) {
+    for (i=0; i < len-1; ++i)
+      control_printf_midreply(conn, 552,
+                              "Unrecognized configuration key \"%s\"",
+                              (char*)smartlist_get(unrecognized, i));
+    control_printf_endreply(conn, 552,
+                            "Unrecognized configuration key \"%s\"",
+                            (char*)smartlist_get(unrecognized, len-1));
+  } else if ((len = smartlist_len(answers))) {
+    char *tmp = smartlist_get(answers, len-1);
+    tor_assert(strlen(tmp)>4);
+    tmp[3] = ' ';
+    msg = smartlist_join_strings(answers, "", 0, &msg_len);
+    connection_buf_add(msg, msg_len, TO_CONN(conn));
+  } else {
+    send_control_done(conn);
+  }
+
+  SMARTLIST_FOREACH(answers, char *, cp, tor_free(cp));
+  smartlist_free(answers);
+  smartlist_free(unrecognized);
+
+  tor_free(msg);
+
+  return 0;
+}
+
+static const control_cmd_syntax_t loadconf_syntax = {
+  .want_cmddata = true
+};
+
+/** Called when we get a +LOADCONF message. */
+static int
+handle_control_loadconf(control_connection_t *conn,
+                        const control_cmd_args_t *args)
+{
+  setopt_err_t retval;
+  char *errstring = NULL;
+
+  retval = options_init_from_string(NULL, args->cmddata,
+                                    CMD_RUN_TOR, NULL, &errstring);
+
+  if (retval != SETOPT_OK)
+    log_warn(LD_CONTROL,
+             "Controller gave us config file that didn't validate: %s",
+             errstring);
+
+#define SEND_ERRMSG(code, msg)                          \
+  control_printf_endreply(conn, code, msg "%s%s",       \
+                          errstring ? ": " : "",        \
+                          errstring ? errstring : "")
+  switch (retval) {
+  case SETOPT_ERR_PARSE:
+    SEND_ERRMSG(552, "Invalid config file");
+    break;
+  case SETOPT_ERR_TRANSITION:
+    SEND_ERRMSG(553, "Transition not allowed");
+    break;
+  case SETOPT_ERR_SETTING:
+    SEND_ERRMSG(553, "Unable to set option");
+    break;
+  case SETOPT_ERR_MISC:
+  default:
+    SEND_ERRMSG(550, "Unable to load config");
+    break;
+  case SETOPT_OK:
+    send_control_done(conn);
+    break;
+  }
+#undef SEND_ERRMSG
+  tor_free(errstring);
+  return 0;
+}
+
+static const control_cmd_syntax_t setevents_syntax = {
+  .max_args = UINT_MAX
+};
+
+/** Called when we get a SETEVENTS message: update conn->event_mask,
+ * and reply with DONE or ERROR. */
+static int
+handle_control_setevents(control_connection_t *conn,
+                         const control_cmd_args_t *args)
+{
+  int event_code;
+  event_mask_t event_mask = 0;
+  const smartlist_t *events = args->args;
+
+  SMARTLIST_FOREACH_BEGIN(events, const char *, ev)
+    {
+      if (!strcasecmp(ev, "EXTENDED") ||
+          !strcasecmp(ev, "AUTHDIR_NEWDESCS")) {
+        log_warn(LD_CONTROL, "The \"%s\" SETEVENTS argument is no longer "
+                 "supported.", ev);
+        continue;
+      } else {
+        int i;
+        event_code = -1;
+
+        for (i = 0; control_event_table[i].event_name != NULL; ++i) {
+          if (!strcasecmp(ev, control_event_table[i].event_name)) {
+            event_code = control_event_table[i].event_code;
+            break;
+          }
+        }
+
+        if (event_code == -1) {
+          control_printf_endreply(conn, 552, "Unrecognized event \"%s\"", ev);
+          return 0;
+        }
+      }
+      event_mask |= (((event_mask_t)1) << event_code);
+    }
+  SMARTLIST_FOREACH_END(ev);
+
+  conn->event_mask = event_mask;
+
+  control_update_global_event_mask();
+  send_control_done(conn);
+  return 0;
+}
+
+static const control_cmd_syntax_t saveconf_syntax = {
+  .max_args = 0,
+  .accept_keywords = true,
+  .kvline_flags=KV_OMIT_VALS,
+};
+
+/** Called when we get a SAVECONF command. Try to flush the current options to
+ * disk, and report success or failure. */
+static int
+handle_control_saveconf(control_connection_t *conn,
+                        const control_cmd_args_t *args)
+{
+  bool force = config_lines_contain_flag(args->kwargs, "FORCE");
+  const or_options_t *options = get_options();
+  if ((!force && options->IncludeUsed) || options_save_current() < 0) {
+    control_write_endreply(conn, 551,
+                           "Unable to write configuration to disk.");
+  } else {
+    send_control_done(conn);
+  }
+  return 0;
+}
+
+static const control_cmd_syntax_t signal_syntax = {
+  .min_args = 1,
+  .max_args = 1,
+};
+
+/** Called when we get a SIGNAL command. React to the provided signal, and
+ * report success or failure. (If the signal results in a shutdown, success
+ * may not be reported.) */
+static int
+handle_control_signal(control_connection_t *conn,
+                      const control_cmd_args_t *args)
+{
+  int sig = -1;
+  int i;
+
+  tor_assert(smartlist_len(args->args) == 1);
+  const char *s = smartlist_get(args->args, 0);
+
+  for (i = 0; signal_table[i].signal_name != NULL; ++i) {
+    if (!strcasecmp(s, signal_table[i].signal_name)) {
+      sig = signal_table[i].sig;
+      break;
+    }
+  }
+
+  if (sig < 0)
+    control_printf_endreply(conn, 552, "Unrecognized signal code \"%s\"", s);
+  if (sig < 0)
+    return 0;
+
+  send_control_done(conn);
+  /* Flush the "done" first if the signal might make us shut down. */
+  if (sig == SIGTERM || sig == SIGINT)
+    connection_flush(TO_CONN(conn));
+
+  activate_signal(sig);
+
+  return 0;
+}
+
+static const control_cmd_syntax_t takeownership_syntax = {
+  .max_args = UINT_MAX, // This should probably become zero. XXXXX
+};
+
+/** Called when we get a TAKEOWNERSHIP command.  Mark this connection
+ * as an owning connection, so that we will exit if the connection
+ * closes. */
+static int
+handle_control_takeownership(control_connection_t *conn,
+                             const control_cmd_args_t *args)
+{
+  (void)args;
+
+  conn->is_owning_control_connection = 1;
+
+  log_info(LD_CONTROL, "Control connection %d has taken ownership of this "
+           "Tor instance.",
+           (int)(conn->base_.s));
+
+  send_control_done(conn);
+  return 0;
+}
+
+static const control_cmd_syntax_t dropownership_syntax = {
+  .max_args = UINT_MAX, // This should probably become zero. XXXXX
+};
+
+/** Called when we get a DROPOWNERSHIP command.  Mark this connection
+ * as a non-owning connection, so that we will not exit if the connection
+ * closes. */
+static int
+handle_control_dropownership(control_connection_t *conn,
+                             const control_cmd_args_t *args)
+{
+  (void)args;
+
+  conn->is_owning_control_connection = 0;
+
+  log_info(LD_CONTROL, "Control connection %d has dropped ownership of this "
+           "Tor instance.",
+           (int)(conn->base_.s));
+
+  send_control_done(conn);
+  return 0;
+}
+
+/** Given a text circuit <b>id</b>, return the corresponding circuit. */
+static origin_circuit_t *
+get_circ(const char *id)
+{
+  uint32_t n_id;
+  int ok;
+  n_id = (uint32_t) tor_parse_ulong(id, 10, 0, UINT32_MAX, &ok, NULL);
+  if (!ok)
+    return NULL;
+  return circuit_get_by_global_id(n_id);
+}
+
+/** Given a text stream <b>id</b>, return the corresponding AP connection. */
+static entry_connection_t *
+get_stream(const char *id)
+{
+  uint64_t n_id;
+  int ok;
+  connection_t *conn;
+  n_id = tor_parse_uint64(id, 10, 0, UINT64_MAX, &ok, NULL);
+  if (!ok)
+    return NULL;
+  conn = connection_get_by_global_id(n_id);
+  if (!conn || conn->type != CONN_TYPE_AP || conn->marked_for_close)
+    return NULL;
+  return TO_ENTRY_CONN(conn);
+}
+
+/** Helper for setconf and resetconf. Acts like setconf, except
+ * it passes <b>use_defaults</b> on to options_trial_assign().  Modifies the
+ * contents of body.
+ */
+static int
+control_setconf_helper(control_connection_t *conn,
+                       const control_cmd_args_t *args,
+                       int use_defaults)
+{
+  setopt_err_t opt_err;
+  char *errstring = NULL;
+  const unsigned flags =
+    CAL_CLEAR_FIRST | (use_defaults ? CAL_USE_DEFAULTS : 0);
+
+  // We need a copy here, since confparse.c wants to canonicalize cases.
+  config_line_t *lines = config_lines_dup(args->kwargs);
+
+  opt_err = options_trial_assign(lines, flags, &errstring);
+  {
+#define SEND_ERRMSG(code, msg)                                  \
+    control_printf_endreply(conn, code, msg ": %s", errstring);
+
+    switch (opt_err) {
+      case SETOPT_ERR_MISC:
+        SEND_ERRMSG(552, "Unrecognized option");
+        break;
+      case SETOPT_ERR_PARSE:
+        SEND_ERRMSG(513, "Unacceptable option value");
+        break;
+      case SETOPT_ERR_TRANSITION:
+        SEND_ERRMSG(553, "Transition not allowed");
+        break;
+      case SETOPT_ERR_SETTING:
+      default:
+        SEND_ERRMSG(553, "Unable to set option");
+        break;
+      case SETOPT_OK:
+        config_free_lines(lines);
+        send_control_done(conn);
+        return 0;
+    }
+#undef SEND_ERRMSG
+    log_warn(LD_CONTROL,
+             "Controller gave us config lines that didn't validate: %s",
+             errstring);
+    config_free_lines(lines);
+    tor_free(errstring);
+    return 0;
+  }
+}
+
+/** Return true iff <b>addr</b> is unusable as a mapaddress target because of
+ * containing funny characters. */
+static int
+address_is_invalid_mapaddress_target(const char *addr)
+{
+  if (!strcmpstart(addr, "*."))
+    return address_is_invalid_destination(addr+2, 1);
+  else
+    return address_is_invalid_destination(addr, 1);
+}
+
+static const control_cmd_syntax_t mapaddress_syntax = {
+  .max_args=1,
+  .accept_keywords=true,
+};
+
+/** Called when we get a MAPADDRESS command; try to bind all listed addresses,
+ * and report success or failure. */
+static int
+handle_control_mapaddress(control_connection_t *conn,
+                          const control_cmd_args_t *args)
+{
+  smartlist_t *reply;
+  char *r;
+  size_t sz;
+
+  reply = smartlist_new();
+  const config_line_t *line;
+  for (line = args->kwargs; line; line = line->next) {
+    const char *from = line->key;
+    const char *to = line->value;
+    {
+      if (address_is_invalid_mapaddress_target(to)) {
+        smartlist_add_asprintf(reply,
+                     "512-syntax error: invalid address '%s'", to);
+        log_warn(LD_CONTROL,
+                 "Skipping invalid argument '%s' in MapAddress msg", to);
+      } else if (!strcmp(from, ".") || !strcmp(from, "0.0.0.0") ||
+                 !strcmp(from, "::")) {
+        const char type =
+          !strcmp(from,".") ? RESOLVED_TYPE_HOSTNAME :
+          (!strcmp(from, "0.0.0.0") ? RESOLVED_TYPE_IPV4 : RESOLVED_TYPE_IPV6);
+        const char *address = addressmap_register_virtual_address(
+                                                     type, tor_strdup(to));
+        if (!address) {
+          smartlist_add_asprintf(reply,
+                   "451-resource exhausted: skipping '%s=%s'", from,to);
+          log_warn(LD_CONTROL,
+                   "Unable to allocate address for '%s' in MapAddress msg",
+                   safe_str_client(to));
+        } else {
+          smartlist_add_asprintf(reply, "250-%s=%s", address, to);
+        }
+      } else {
+        const char *msg;
+        if (addressmap_register_auto(from, to, 1,
+                                     ADDRMAPSRC_CONTROLLER, &msg) < 0) {
+          smartlist_add_asprintf(reply,
+                                 "512-syntax error: invalid address mapping "
+                                 " '%s=%s': %s", from, to, msg);
+          log_warn(LD_CONTROL,
+                   "Skipping invalid argument '%s=%s' in MapAddress msg: %s",
+                   from, to, msg);
+        } else {
+          smartlist_add_asprintf(reply, "250-%s=%s", from, to);
+        }
+      }
+    }
+  }
+
+  if (smartlist_len(reply)) {
+    ((char*)smartlist_get(reply,smartlist_len(reply)-1))[3] = ' ';
+    r = smartlist_join_strings(reply, "\r\n", 1, &sz);
+    connection_buf_add(r, sz, TO_CONN(conn));
+    tor_free(r);
+  } else {
+    const char *response =
+      "512 syntax error: not enough arguments to mapaddress.\r\n";
+    connection_buf_add(response, strlen(response), TO_CONN(conn));
+  }
+
+  SMARTLIST_FOREACH(reply, char *, cp, tor_free(cp));
+  smartlist_free(reply);
+  return 0;
+}
+
+/** Given a string, convert it to a circuit purpose. */
+static uint8_t
+circuit_purpose_from_string(const char *string)
+{
+  if (!strcasecmpstart(string, "purpose="))
+    string += strlen("purpose=");
+
+  if (!strcasecmp(string, "general"))
+    return CIRCUIT_PURPOSE_C_GENERAL;
+  else if (!strcasecmp(string, "controller"))
+    return CIRCUIT_PURPOSE_CONTROLLER;
+  else
+    return CIRCUIT_PURPOSE_UNKNOWN;
+}
+
+static const control_cmd_syntax_t extendcircuit_syntax = {
+  .min_args=1,
+  .max_args=1, // see note in function
+  .accept_keywords=true,
+  .kvline_flags=KV_OMIT_VALS
+};
+
+/** Called when we get an EXTENDCIRCUIT message.  Try to extend the listed
+ * circuit, and report success or failure. */
+static int
+handle_control_extendcircuit(control_connection_t *conn,
+                             const control_cmd_args_t *args)
+{
+  smartlist_t *router_nicknames=smartlist_new(), *nodes=NULL;
+  origin_circuit_t *circ = NULL;
+  uint8_t intended_purpose = CIRCUIT_PURPOSE_C_GENERAL;
+  const config_line_t *kwargs = args->kwargs;
+  const char *circ_id = smartlist_get(args->args, 0);
+  const char *path_str = NULL;
+  char *path_str_alloc = NULL;
+
+  /* The syntax for this command is unfortunate. The second argument is
+     optional, and is a comma-separated list long-format fingerprints, which
+     can (historically!) contain an equals sign.
+
+     Here we check the second argument to see if it's a path, and if so we
+     remove it from the kwargs list and put it in path_str.
+  */
+  if (kwargs) {
+    const config_line_t *arg1 = kwargs;
+    if (!strcmp(arg1->value, "")) {
+      path_str = arg1->key;
+      kwargs = kwargs->next;
+    } else if (arg1->key[0] == '$') {
+      tor_asprintf(&path_str_alloc, "%s=%s", arg1->key, arg1->value);
+      path_str = path_str_alloc;
+      kwargs = kwargs->next;
+    }
+  }
+
+  const config_line_t *purpose_line = config_line_find_case(kwargs, "PURPOSE");
+  bool zero_circ = !strcmp("0", circ_id);
+
+  if (purpose_line) {
+    intended_purpose = circuit_purpose_from_string(purpose_line->value);
+    if (intended_purpose == CIRCUIT_PURPOSE_UNKNOWN) {
+      control_printf_endreply(conn, 552, "Unknown purpose \"%s\"",
+                              purpose_line->value);
+      goto done;
+    }
+  }
+
+  if (zero_circ) {
+    if (!path_str) {
+      // "EXTENDCIRCUIT 0" with no path.
+      circ = circuit_launch(intended_purpose, CIRCLAUNCH_NEED_CAPACITY);
+      if (!circ) {
+        control_write_endreply(conn, 551, "Couldn't start circuit");
+      } else {
+        control_printf_endreply(conn, 250, "EXTENDED %lu",
+                                (unsigned long)circ->global_identifier);
+      }
+      goto done;
+    }
+  }
+
+  if (!zero_circ && !(circ = get_circ(circ_id))) {
+    control_printf_endreply(conn, 552, "Unknown circuit \"%s\"", circ_id);
+    goto done;
+  }
+
+  if (!path_str) {
+    control_write_endreply(conn, 512, "syntax error: path required.");
+    goto done;
+  }
+
+  smartlist_split_string(router_nicknames, path_str, ",", 0, 0);
+
+  nodes = smartlist_new();
+  bool first_node = zero_circ;
+  SMARTLIST_FOREACH_BEGIN(router_nicknames, const char *, n) {
+    const node_t *node = node_get_by_nickname(n, 0);
+    if (!node) {
+      control_printf_endreply(conn, 552, "No such router \"%s\"", n);
+      goto done;
+    }
+    if (!node_has_preferred_descriptor(node, first_node)) {
+      control_printf_endreply(conn, 552, "No descriptor for \"%s\"", n);
+      goto done;
+    }
+    smartlist_add(nodes, (void*)node);
+    first_node = false;
+  } SMARTLIST_FOREACH_END(n);
+
+  if (!smartlist_len(nodes)) {
+    control_write_endreply(conn, 512, "No router names provided");
+    goto done;
+  }
+
+  if (zero_circ) {
+    /* start a new circuit */
+    circ = origin_circuit_init(intended_purpose, 0);
+  }
+
+  /* now circ refers to something that is ready to be extended */
+  first_node = zero_circ;
+  SMARTLIST_FOREACH(nodes, const node_t *, node,
+  {
+    extend_info_t *info = extend_info_from_node(node, first_node);
+    if (!info) {
+      tor_assert_nonfatal(first_node);
+      log_warn(LD_CONTROL,
+               "controller tried to connect to a node that lacks a suitable "
+               "descriptor, or which doesn't have any "
+               "addresses that are allowed by the firewall configuration; "
+               "circuit marked for closing.");
+      circuit_mark_for_close(TO_CIRCUIT(circ), -END_CIRC_REASON_CONNECTFAILED);
+      connection_write_str_to_buf("551 Couldn't start circuit\r\n", conn);
+      goto done;
+    }
+    circuit_append_new_exit(circ, info);
+    if (circ->build_state->desired_path_len > 1) {
+      circ->build_state->onehop_tunnel = 0;
+    }
+    extend_info_free(info);
+    first_node = 0;
+  });
+
+  /* now that we've populated the cpath, start extending */
+  if (zero_circ) {
+    int err_reason = 0;
+    if ((err_reason = circuit_handle_first_hop(circ)) < 0) {
+      circuit_mark_for_close(TO_CIRCUIT(circ), -err_reason);
+      control_write_endreply(conn, 551, "Couldn't start circuit");
+      goto done;
+    }
+  } else {
+    if (circ->base_.state == CIRCUIT_STATE_OPEN ||
+        circ->base_.state == CIRCUIT_STATE_GUARD_WAIT) {
+      int err_reason = 0;
+      circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_BUILDING);
+      if ((err_reason = circuit_send_next_onion_skin(circ)) < 0) {
+        log_info(LD_CONTROL,
+                 "send_next_onion_skin failed; circuit marked for closing.");
+        circuit_mark_for_close(TO_CIRCUIT(circ), -err_reason);
+        control_write_endreply(conn, 551, "Couldn't send onion skin");
+        goto done;
+      }
+    }
+  }
+
+  control_printf_endreply(conn, 250, "EXTENDED %lu",
+                          (unsigned long)circ->global_identifier);
+  if (zero_circ) /* send a 'launched' event, for completeness */
+    circuit_event_status(circ, CIRC_EVENT_LAUNCHED, 0);
+ done:
+  SMARTLIST_FOREACH(router_nicknames, char *, n, tor_free(n));
+  smartlist_free(router_nicknames);
+  smartlist_free(nodes);
+  tor_free(path_str_alloc);
+  return 0;
+}
+
+static const control_cmd_syntax_t setcircuitpurpose_syntax = {
+  .max_args=1,
+  .accept_keywords=true,
+};
+
+/** Called when we get a SETCIRCUITPURPOSE message. If we can find the
+ * circuit and it's a valid purpose, change it. */
+static int
+handle_control_setcircuitpurpose(control_connection_t *conn,
+                                 const control_cmd_args_t *args)
+{
+  origin_circuit_t *circ = NULL;
+  uint8_t new_purpose;
+  const char *circ_id = smartlist_get(args->args,0);
+
+  if (!(circ = get_circ(circ_id))) {
+    control_printf_endreply(conn, 552, "Unknown circuit \"%s\"", circ_id);
+    goto done;
+  }
+
+  {
+    const config_line_t *purp = config_line_find_case(args->kwargs, "PURPOSE");
+    if (!purp) {
+      control_write_endreply(conn, 552, "No purpose given");
+      goto done;
+    }
+    new_purpose = circuit_purpose_from_string(purp->value);
+    if (new_purpose == CIRCUIT_PURPOSE_UNKNOWN) {
+      control_printf_endreply(conn, 552, "Unknown purpose \"%s\"",
+                              purp->value);
+      goto done;
+    }
+  }
+
+  circuit_change_purpose(TO_CIRCUIT(circ), new_purpose);
+  send_control_done(conn);
+
+ done:
+  return 0;
+}
+
+static const char *attachstream_keywords[] = {
+  "HOP", NULL
+};
+static const control_cmd_syntax_t attachstream_syntax = {
+  .min_args=2, .max_args=2,
+  .accept_keywords=true,
+  .allowed_keywords=attachstream_keywords
+};
+
+/** Called when we get an ATTACHSTREAM message.  Try to attach the requested
+ * stream, and report success or failure. */
+static int
+handle_control_attachstream(control_connection_t *conn,
+                            const control_cmd_args_t *args)
+{
+  entry_connection_t *ap_conn = NULL;
+  origin_circuit_t *circ = NULL;
+  crypt_path_t *cpath=NULL;
+  int hop=0, hop_line_ok=1;
+  const char *stream_id = smartlist_get(args->args, 0);
+  const char *circ_id = smartlist_get(args->args, 1);
+  int zero_circ = !strcmp(circ_id, "0");
+  const config_line_t *hoparg = config_line_find_case(args->kwargs, "HOP");
+
+  if (!(ap_conn = get_stream(stream_id))) {
+    control_printf_endreply(conn, 552, "Unknown stream \"%s\"", stream_id);
+    return 0;
+  } else if (!zero_circ && !(circ = get_circ(circ_id))) {
+    control_printf_endreply(conn, 552, "Unknown circuit \"%s\"", circ_id);
+    return 0;
+  } else if (circ) {
+    if (hoparg) {
+      hop = (int) tor_parse_ulong(hoparg->value, 10, 0, INT_MAX,
+                                  &hop_line_ok, NULL);
+      if (!hop_line_ok) { /* broken hop line */
+        control_printf_endreply(conn, 552, "Bad value hop=%s",
+                                hoparg->value);
+        return 0;
+      }
+    }
+  }
+
+  if (ENTRY_TO_CONN(ap_conn)->state != AP_CONN_STATE_CONTROLLER_WAIT &&
+      ENTRY_TO_CONN(ap_conn)->state != AP_CONN_STATE_CONNECT_WAIT &&
+      ENTRY_TO_CONN(ap_conn)->state != AP_CONN_STATE_RESOLVE_WAIT) {
+    control_write_endreply(conn, 555,
+                           "Connection is not managed by controller.");
+    return 0;
+  }
+
+  /* Do we need to detach it first? */
+  if (ENTRY_TO_CONN(ap_conn)->state != AP_CONN_STATE_CONTROLLER_WAIT) {
+    edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(ap_conn);
+    circuit_t *tmpcirc = circuit_get_by_edge_conn(edge_conn);
+    connection_edge_end(edge_conn, END_STREAM_REASON_TIMEOUT);
+    /* Un-mark it as ending, since we're going to reuse it. */
+    edge_conn->edge_has_sent_end = 0;
+    edge_conn->end_reason = 0;
+    if (tmpcirc)
+      circuit_detach_stream(tmpcirc, edge_conn);
+    CONNECTION_AP_EXPECT_NONPENDING(ap_conn);
+    TO_CONN(edge_conn)->state = AP_CONN_STATE_CONTROLLER_WAIT;
+  }
+
+  if (circ && (circ->base_.state != CIRCUIT_STATE_OPEN)) {
+    control_write_endreply(conn, 551,
+                           "Can't attach stream to non-open origin circuit");
+    return 0;
+  }
+  /* Is this a single hop circuit? */
+  if (circ && (circuit_get_cpath_len(circ)<2 || hop==1)) {
+    control_write_endreply(conn, 551,
+                           "Can't attach stream to this one-hop circuit.");
+    return 0;
+  }
+
+  if (circ && hop>0) {
+    /* find this hop in the circuit, and set cpath */
+    cpath = circuit_get_cpath_hop(circ, hop);
+    if (!cpath) {
+      control_printf_endreply(conn, 551, "Circuit doesn't have %d hops.", hop);
+      return 0;
+    }
+  }
+  if (connection_ap_handshake_rewrite_and_attach(ap_conn, circ, cpath) < 0) {
+    control_write_endreply(conn, 551, "Unable to attach stream");
+    return 0;
+  }
+  send_control_done(conn);
+  return 0;
+}
+
+static const char *postdescriptor_keywords[] = {
+  "cache", "purpose", NULL,
+};
+
+static const control_cmd_syntax_t postdescriptor_syntax = {
+  .max_args = 0,
+  .accept_keywords = true,
+  .allowed_keywords = postdescriptor_keywords,
+  .want_cmddata = true,
+};
+
+/** Called when we get a POSTDESCRIPTOR message.  Try to learn the provided
+ * descriptor, and report success or failure. */
+static int
+handle_control_postdescriptor(control_connection_t *conn,
+                              const control_cmd_args_t *args)
+{
+  const char *msg=NULL;
+  uint8_t purpose = ROUTER_PURPOSE_GENERAL;
+  int cache = 0; /* eventually, we may switch this to 1 */
+  const config_line_t *line;
+
+  line = config_line_find_case(args->kwargs, "purpose");
+  if (line) {
+    purpose = router_purpose_from_string(line->value);
+    if (purpose == ROUTER_PURPOSE_UNKNOWN) {
+      control_printf_endreply(conn, 552, "Unknown purpose \"%s\"",
+                              line->value);
+      goto done;
+    }
+  }
+  line = config_line_find_case(args->kwargs, "cache");
+  if (line) {
+    if (!strcasecmp(line->value, "no"))
+      cache = 0;
+    else if (!strcasecmp(line->value, "yes"))
+      cache = 1;
+    else {
+      control_printf_endreply(conn, 552, "Unknown cache request \"%s\"",
+                              line->value);
+      goto done;
+    }
+  }
+
+  switch (router_load_single_router(args->cmddata, purpose, cache, &msg)) {
+  case -1:
+    if (!msg) msg = "Could not parse descriptor";
+    control_write_endreply(conn, 554, msg);
+    break;
+  case 0:
+    if (!msg) msg = "Descriptor not added";
+    control_write_endreply(conn, 251, msg);
+    break;
+  case 1:
+    send_control_done(conn);
+    break;
+  }
+
+ done:
+  return 0;
+}
+
+static const control_cmd_syntax_t redirectstream_syntax = {
+  .min_args = 2,
+  .max_args = UINT_MAX, // XXX should be 3.
+};
+
+/** Called when we receive a REDIRECTSTERAM command.  Try to change the target
+ * address of the named AP stream, and report success or failure. */
+static int
+handle_control_redirectstream(control_connection_t *conn,
+                              const control_cmd_args_t *cmd_args)
+{
+  entry_connection_t *ap_conn = NULL;
+  char *new_addr = NULL;
+  uint16_t new_port = 0;
+  const smartlist_t *args = cmd_args->args;
+
+  if (!(ap_conn = get_stream(smartlist_get(args, 0)))
+           || !ap_conn->socks_request) {
+    control_printf_endreply(conn, 552, "Unknown stream \"%s\"",
+                            (char*)smartlist_get(args, 0));
+  } else {
+    int ok = 1;
+    if (smartlist_len(args) > 2) { /* they included a port too */
+      new_port = (uint16_t) tor_parse_ulong(smartlist_get(args, 2),
+                                            10, 1, 65535, &ok, NULL);
+    }
+    if (!ok) {
+      control_printf_endreply(conn, 512, "Cannot parse port \"%s\"",
+                              (char*)smartlist_get(args, 2));
+    } else {
+      new_addr = tor_strdup(smartlist_get(args, 1));
+    }
+  }
+
+  if (!new_addr)
+    return 0;
+
+  strlcpy(ap_conn->socks_request->address, new_addr,
+          sizeof(ap_conn->socks_request->address));
+  if (new_port)
+    ap_conn->socks_request->port = new_port;
+  tor_free(new_addr);
+  send_control_done(conn);
+  return 0;
+}
+
+static const control_cmd_syntax_t closestream_syntax = {
+  .min_args = 2,
+  .max_args = UINT_MAX, /* XXXX This is the original behavior, but
+                         * maybe we should change the spec. */
+};
+
+/** Called when we get a CLOSESTREAM command; try to close the named stream
+ * and report success or failure. */
+static int
+handle_control_closestream(control_connection_t *conn,
+                           const control_cmd_args_t *cmd_args)
+{
+  entry_connection_t *ap_conn=NULL;
+  uint8_t reason=0;
+  int ok;
+  const smartlist_t *args = cmd_args->args;
+
+  tor_assert(smartlist_len(args) >= 2);
+
+  if (!(ap_conn = get_stream(smartlist_get(args, 0))))
+    control_printf_endreply(conn, 552, "Unknown stream \"%s\"",
+                            (char*)smartlist_get(args, 0));
+  else {
+    reason = (uint8_t) tor_parse_ulong(smartlist_get(args,1), 10, 0, 255,
+                                       &ok, NULL);
+    if (!ok) {
+      control_printf_endreply(conn, 552, "Unrecognized reason \"%s\"",
+                              (char*)smartlist_get(args, 1));
+      ap_conn = NULL;
+    }
+  }
+  if (!ap_conn)
+    return 0;
+
+  connection_mark_unattached_ap(ap_conn, reason);
+  send_control_done(conn);
+  return 0;
+}
+
+static const control_cmd_syntax_t closecircuit_syntax = {
+  .min_args=1, .max_args=1,
+  .accept_keywords=true,
+  .kvline_flags=KV_OMIT_VALS,
+  // XXXX we might want to exclude unrecognized flags, but for now we
+  // XXXX just ignore them for backward compatibility.
+};
+
+/** Called when we get a CLOSECIRCUIT command; try to close the named circuit
+ * and report success or failure. */
+static int
+handle_control_closecircuit(control_connection_t *conn,
+                            const control_cmd_args_t *args)
+{
+  const char *circ_id = smartlist_get(args->args, 0);
+  origin_circuit_t *circ = NULL;
+
+  if (!(circ=get_circ(circ_id))) {
+    control_printf_endreply(conn, 552, "Unknown circuit \"%s\"", circ_id);
+    return 0;
+  }
+
+  bool safe =  config_lines_contain_flag(args->kwargs, "IfUnused");
+
+  if (!safe || !circ->p_streams) {
+    circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_REQUESTED);
+  }
+
+  send_control_done(conn);
+  return 0;
+}
+
+static const control_cmd_syntax_t resolve_syntax = {
+  .max_args=0,
+  .accept_keywords=true,
+  .kvline_flags=KV_OMIT_VALS,
+};
+
+/** Called when we get a RESOLVE command: start trying to resolve
+ * the listed addresses. */
+static int
+handle_control_resolve(control_connection_t *conn,
+                       const control_cmd_args_t *args)
+{
+  smartlist_t *failed;
+  int is_reverse = 0;
+
+  if (!(conn->event_mask & (((event_mask_t)1)<<EVENT_ADDRMAP))) {
+    log_warn(LD_CONTROL, "Controller asked us to resolve an address, but "
+             "isn't listening for ADDRMAP events.  It probably won't see "
+             "the answer.");
+  }
+
+  {
+    const config_line_t *modearg = config_line_find_case(args->kwargs, "mode");
+    if (modearg && !strcasecmp(modearg->value, "reverse"))
+      is_reverse = 1;
+  }
+  failed = smartlist_new();
+  for (const config_line_t *line = args->kwargs; line; line = line->next) {
+    if (!strlen(line->value)) {
+      const char *addr = line->key;
+      if (dnsserv_launch_request(addr, is_reverse, conn)<0)
+        smartlist_add(failed, (char*)addr);
+    } else {
+      // XXXX arguably we should reject unrecognized keyword arguments,
+      // XXXX but the old implementation didn't do that.
+    }
+  }
+
+  send_control_done(conn);
+  SMARTLIST_FOREACH(failed, const char *, arg, {
+      control_event_address_mapped(arg, arg, time(NULL),
+                                   "internal", 0);
+  });
+
+  smartlist_free(failed);
+  return 0;
+}
+
+static const control_cmd_syntax_t protocolinfo_syntax = {
+  .max_args = UINT_MAX
+};
+
+/** Called when we get a PROTOCOLINFO command: send back a reply. */
+static int
+handle_control_protocolinfo(control_connection_t *conn,
+                            const control_cmd_args_t *cmd_args)
+{
+  const char *bad_arg = NULL;
+  const smartlist_t *args = cmd_args->args;
+
+  conn->have_sent_protocolinfo = 1;
+
+  SMARTLIST_FOREACH(args, const char *, arg, {
+      int ok;
+      tor_parse_long(arg, 10, 0, LONG_MAX, &ok, NULL);
+      if (!ok) {
+        bad_arg = arg;
+        break;
+      }
+    });
+  if (bad_arg) {
+    control_printf_endreply(conn, 513, "No such version %s",
+                            escaped(bad_arg));
+    /* Don't tolerate bad arguments when not authenticated. */
+    if (!STATE_IS_OPEN(TO_CONN(conn)->state))
+      connection_mark_for_close(TO_CONN(conn));
+    goto done;
+  } else {
+    const or_options_t *options = get_options();
+    int cookies = options->CookieAuthentication;
+    char *cfile = get_controller_cookie_file_name();
+    char *abs_cfile;
+    char *esc_cfile;
+    char *methods;
+    abs_cfile = make_path_absolute(cfile);
+    esc_cfile = esc_for_log(abs_cfile);
+    {
+      int passwd = (options->HashedControlPassword != NULL ||
+                    options->HashedControlSessionPassword != NULL);
+      smartlist_t *mlist = smartlist_new();
+      if (cookies) {
+        smartlist_add(mlist, (char*)"COOKIE");
+        smartlist_add(mlist, (char*)"SAFECOOKIE");
+      }
+      if (passwd)
+        smartlist_add(mlist, (char*)"HASHEDPASSWORD");
+      if (!cookies && !passwd)
+        smartlist_add(mlist, (char*)"NULL");
+      methods = smartlist_join_strings(mlist, ",", 0, NULL);
+      smartlist_free(mlist);
+    }
+
+    control_write_midreply(conn, 250, "PROTOCOLINFO 1");
+    control_printf_midreply(conn, 250, "AUTH METHODS=%s%s%s", methods,
+                            cookies?" COOKIEFILE=":"",
+                            cookies?esc_cfile:"");
+    control_printf_midreply(conn, 250, "VERSION Tor=%s", escaped(VERSION));
+    send_control_done(conn);
+
+    tor_free(methods);
+    tor_free(cfile);
+    tor_free(abs_cfile);
+    tor_free(esc_cfile);
+  }
+ done:
+  return 0;
+}
+
+static const control_cmd_syntax_t usefeature_syntax = {
+  .max_args = UINT_MAX
+};
+
+/** Called when we get a USEFEATURE command: parse the feature list, and
+ * set up the control_connection's options properly. */
+static int
+handle_control_usefeature(control_connection_t *conn,
+                          const control_cmd_args_t *cmd_args)
+{
+  const smartlist_t *args = cmd_args->args;
+  int bad = 0;
+  SMARTLIST_FOREACH_BEGIN(args, const char *, arg) {
+      if (!strcasecmp(arg, "VERBOSE_NAMES"))
+        ;
+      else if (!strcasecmp(arg, "EXTENDED_EVENTS"))
+        ;
+      else {
+        control_printf_endreply(conn, 552, "Unrecognized feature \"%s\"",
+                                arg);
+        bad = 1;
+        break;
+      }
+  } SMARTLIST_FOREACH_END(arg);
+
+  if (!bad) {
+    send_control_done(conn);
+  }
+
+  return 0;
+}
+
+static const control_cmd_syntax_t dropguards_syntax = {
+  .max_args = 0,
+};
+
+/** Implementation for the DROPGUARDS command. */
+static int
+handle_control_dropguards(control_connection_t *conn,
+                          const control_cmd_args_t *args)
+{
+  (void) args; /* We don't take arguments. */
+
+  static int have_warned = 0;
+  if (! have_warned) {
+    log_warn(LD_CONTROL, "DROPGUARDS is dangerous; make sure you understand "
+             "the risks before using it. It may be removed in a future "
+             "version of Tor.");
+    have_warned = 1;
+  }
+
+  remove_all_entry_guards();
+  send_control_done(conn);
+
+  return 0;
+}
+
+static const char *hsfetch_keywords[] = {
+  "SERVER", NULL,
+};
+static const control_cmd_syntax_t hsfetch_syntax = {
+  .min_args = 1, .max_args = 1,
+  .accept_keywords = true,
+  .allowed_keywords = hsfetch_keywords,
+};
+
+/** Implementation for the HSFETCH command. */
+static int
+handle_control_hsfetch(control_connection_t *conn,
+                       const control_cmd_args_t *args)
+
+{
+  char digest[DIGEST_LEN], *desc_id = NULL;
+  smartlist_t *hsdirs = NULL;
+  static const char *v2_str = "v2-";
+  const size_t v2_str_len = strlen(v2_str);
+  rend_data_t *rend_query = NULL;
+  ed25519_public_key_t v3_pk;
+  uint32_t version;
+  const char *hsaddress = NULL;
+
+  /* Extract the first argument (either HSAddress or DescID). */
+  const char *arg1 = smartlist_get(args->args, 0);
+  /* Test if it's an HS address without the .onion part. */
+  if (rend_valid_v2_service_id(arg1)) {
+    hsaddress = arg1;
+    version = HS_VERSION_TWO;
+  } else if (strcmpstart(arg1, v2_str) == 0 &&
+             rend_valid_descriptor_id(arg1 + v2_str_len) &&
+             base32_decode(digest, sizeof(digest), arg1 + v2_str_len,
+                           REND_DESC_ID_V2_LEN_BASE32) ==
+                REND_DESC_ID_V2_LEN_BASE32) {
+    /* We have a well formed version 2 descriptor ID. Keep the decoded value
+     * of the id. */
+    desc_id = digest;
+    version = HS_VERSION_TWO;
+  } else if (hs_address_is_valid(arg1)) {
+    hsaddress = arg1;
+    version = HS_VERSION_THREE;
+    hs_parse_address(hsaddress, &v3_pk, NULL, NULL);
+  } else {
+    control_printf_endreply(conn, 513, "Invalid argument \"%s\"", arg1);
+    goto done;
+  }
+
+  for (const config_line_t *line = args->kwargs; line; line = line->next) {
+    if (!strcasecmp(line->key, "SERVER")) {
+      const char *server = line->value;
+
+      const node_t *node = node_get_by_hex_id(server, 0);
+      if (!node) {
+        control_printf_endreply(conn, 552, "Server \"%s\" not found", server);
+        goto done;
+      }
+      if (!hsdirs) {
+        /* Stores routerstatus_t cmddata for each specified server. */
+        hsdirs = smartlist_new();
+      }
+      /* Valid server, add it to our local list. */
+      smartlist_add(hsdirs, node->rs);
+    } else {
+      tor_assert_nonfatal_unreached();
+    }
+  }
+
+  if (version == HS_VERSION_TWO) {
+    rend_query = rend_data_client_create(hsaddress, desc_id, NULL,
+                                         REND_NO_AUTH);
+    if (rend_query == NULL) {
+      control_write_endreply(conn, 551, "Error creating the HS query");
+      goto done;
+    }
+  }
+
+  /* Using a descriptor ID, we force the user to provide at least one
+   * hsdir server using the SERVER= option. */
+  if (desc_id && (!hsdirs || !smartlist_len(hsdirs))) {
+    control_write_endreply(conn, 512, "SERVER option is required");
+    goto done;
+  }
+
+  /* We are about to trigger HSDir fetch so send the OK now because after
+   * that 650 event(s) are possible so better to have the 250 OK before them
+   * to avoid out of order replies. */
+  send_control_done(conn);
+
+  /* Trigger the fetch using the built rend query and possibly a list of HS
+   * directory to use. This function ignores the client cache thus this will
+   * always send a fetch command. */
+  if (version == HS_VERSION_TWO) {
+    rend_client_fetch_v2_desc(rend_query, hsdirs);
+  } else if (version == HS_VERSION_THREE) {
+    hs_control_hsfetch_command(&v3_pk, hsdirs);
+  }
+
+ done:
+  /* Contains data pointer that we don't own thus no cleanup. */
+  smartlist_free(hsdirs);
+  rend_data_free(rend_query);
+  return 0;
+}
+
+static const char *hspost_keywords[] = {
+  "SERVER", "HSADDRESS", NULL
+};
+static const control_cmd_syntax_t hspost_syntax = {
+  .min_args = 0, .max_args = 0,
+  .accept_keywords = true,
+  .want_cmddata = true,
+  .allowed_keywords = hspost_keywords
+};
+
+/** Implementation for the HSPOST command. */
+static int
+handle_control_hspost(control_connection_t *conn,
+                      const control_cmd_args_t *args)
+{
+  smartlist_t *hs_dirs = NULL;
+  const char *encoded_desc = args->cmddata;
+  size_t encoded_desc_len = args->cmddata_len;
+  const char *onion_address = NULL;
+  const config_line_t *line;
+
+  for (line = args->kwargs; line; line = line->next) {
+    if (!strcasecmpstart(line->key, "SERVER")) {
+      const char *server = line->value;
+      const node_t *node = node_get_by_hex_id(server, 0);
+
+      if (!node || !node->rs) {
+        control_printf_endreply(conn, 552, "Server \"%s\" not found",
+                                server);
+        goto done;
+      }
+      /* Valid server, add it to our local list. */
+      if (!hs_dirs)
+        hs_dirs = smartlist_new();
+      smartlist_add(hs_dirs, node->rs);
+    } else if (!strcasecmpstart(line->key, "HSADDRESS")) {
+      const char *address = line->value;
+      if (!hs_address_is_valid(address)) {
+        control_write_endreply(conn, 512, "Malformed onion address");
+        goto done;
+      }
+      onion_address = address;
+    } else {
+      tor_assert_nonfatal_unreached();
+    }
+  }
+
+  /* Handle the v3 case. */
+  if (onion_address) {
+    if (hs_control_hspost_command(encoded_desc, onion_address, hs_dirs) < 0) {
+      control_write_endreply(conn, 554, "Invalid descriptor");
+    } else {
+      send_control_done(conn);
+    }
+    goto done;
+  }
+
+  /* From this point on, it is only v2. */
+
+  /*  parse it. */
+  rend_encoded_v2_service_descriptor_t *desc =
+      tor_malloc_zero(sizeof(rend_encoded_v2_service_descriptor_t));
+  desc->desc_str = tor_memdup_nulterm(encoded_desc, encoded_desc_len);
+
+  rend_service_descriptor_t *parsed = NULL;
+  char *intro_content = NULL;
+  size_t intro_size;
+  size_t encoded_size;
+  const char *next_desc;
+  if (!rend_parse_v2_service_descriptor(&parsed, desc->desc_id, &intro_content,
+                                        &intro_size, &encoded_size,
+                                        &next_desc, desc->desc_str, 1)) {
+    /* Post the descriptor. */
+    char serviceid[REND_SERVICE_ID_LEN_BASE32+1];
+    if (!rend_get_service_id(parsed->pk, serviceid)) {
+      smartlist_t *descs = smartlist_new();
+      smartlist_add(descs, desc);
+
+      /* We are about to trigger HS descriptor upload so send the OK now
+       * because after that 650 event(s) are possible so better to have the
+       * 250 OK before them to avoid out of order replies. */
+      send_control_done(conn);
+
+      /* Trigger the descriptor upload */
+      directory_post_to_hs_dir(parsed, descs, hs_dirs, serviceid, 0);
+      smartlist_free(descs);
+    }
+
+    rend_service_descriptor_free(parsed);
+  } else {
+    control_write_endreply(conn, 554, "Invalid descriptor");
+  }
+
+  tor_free(intro_content);
+  rend_encoded_v2_service_descriptor_free(desc);
+ done:
+  smartlist_free(hs_dirs); /* Contents belong to the rend service code. */
+  return 0;
+}
+
+/* Helper function for ADD_ONION that adds an ephemeral service depending on
+ * the given hs_version.
+ *
+ * The secret key in pk depends on the hs_version. The ownership of the key
+ * used in pk is given to the HS subsystem so the caller must stop accessing
+ * it after.
+ *
+ * The port_cfgs is a list of service port. Ownership transferred to service.
+ * The max_streams refers to the MaxStreams= key.
+ * The max_streams_close_circuit refers to the MaxStreamsCloseCircuit key.
+ * The auth_type is the authentication type of the clients in auth_clients.
+ * The ownership of that list is transferred to the service.
+ *
+ * On success (RSAE_OKAY), the address_out points to a newly allocated string
+ * containing the onion address without the .onion part. On error, address_out
+ * is untouched. */
+static hs_service_add_ephemeral_status_t
+add_onion_helper_add_service(int hs_version,
+                             add_onion_secret_key_t *pk,
+                             smartlist_t *port_cfgs, int max_streams,
+                             int max_streams_close_circuit, int auth_type,
+                             smartlist_t *auth_clients, char **address_out)
+{
+  hs_service_add_ephemeral_status_t ret;
+
+  tor_assert(pk);
+  tor_assert(port_cfgs);
+  tor_assert(address_out);
+
+  switch (hs_version) {
+  case HS_VERSION_TWO:
+    ret = rend_service_add_ephemeral(pk->v2, port_cfgs, max_streams,
+                                     max_streams_close_circuit, auth_type,
+                                     auth_clients, address_out);
+    break;
+  case HS_VERSION_THREE:
+    ret = hs_service_add_ephemeral(pk->v3, port_cfgs, max_streams,
+                                   max_streams_close_circuit, address_out);
+    break;
+  default:
+    tor_assert_unreached();
+  }
+
+  return ret;
+}
+
+/** The list of onion services that have been added via ADD_ONION that do not
+ * belong to any particular control connection.
+ */
+static smartlist_t *detached_onion_services = NULL;
+
+/**
+ * Return a list of detached onion services, or NULL if none exist.
+ **/
+smartlist_t *
+get_detached_onion_services(void)
+{
+  return detached_onion_services;
+}
+
+static const char *add_onion_keywords[] = {
+   "Port", "Flags", "MaxStreams", "ClientAuth", NULL
+};
+static const control_cmd_syntax_t add_onion_syntax = {
+  .min_args = 1, .max_args = 1,
+  .accept_keywords = true,
+  .allowed_keywords = add_onion_keywords
+};
+
+/** Called when we get a ADD_ONION command; parse the body, and set up
+ * the new ephemeral Onion Service. */
+static int
+handle_control_add_onion(control_connection_t *conn,
+                         const control_cmd_args_t *args)
+{
+  /* Parse all of the arguments that do not involve handling cryptographic
+   * material first, since there's no reason to touch that at all if any of
+   * the other arguments are malformed.
+   */
+  smartlist_t *port_cfgs = smartlist_new();
+  smartlist_t *auth_clients = NULL;
+  smartlist_t *auth_created_clients = NULL;
+  int discard_pk = 0;
+  int detach = 0;
+  int max_streams = 0;
+  int max_streams_close_circuit = 0;
+  rend_auth_type_t auth_type = REND_NO_AUTH;
+  int non_anonymous = 0;
+  const config_line_t *arg;
+
+  for (arg = args->kwargs; arg; arg = arg->next) {
+    if (!strcasecmp(arg->key, "Port")) {
+      /* "Port=VIRTPORT[,TARGET]". */
+      rend_service_port_config_t *cfg =
+          rend_service_parse_port_config(arg->value, ",", NULL);
+      if (!cfg) {
+        control_write_endreply(conn, 512, "Invalid VIRTPORT/TARGET");
+        goto out;
+      }
+      smartlist_add(port_cfgs, cfg);
+    } else if (!strcasecmp(arg->key, "MaxStreams")) {
+      /* "MaxStreams=[0..65535]". */
+      int ok = 0;
+      max_streams = (int)tor_parse_long(arg->value, 10, 0, 65535, &ok, NULL);
+      if (!ok) {
+        control_write_endreply(conn, 512, "Invalid MaxStreams");
+        goto out;
+      }
+    } else if (!strcasecmp(arg->key, "Flags")) {
+      /* "Flags=Flag[,Flag]", where Flag can be:
+       *   * 'DiscardPK' - If tor generates the keypair, do not include it in
+       *                   the response.
+       *   * 'Detach' - Do not tie this onion service to any particular control
+       *                connection.
+       *   * 'MaxStreamsCloseCircuit' - Close the circuit if MaxStreams is
+       *                                exceeded.
+       *   * 'BasicAuth' - Client authorization using the 'basic' method.
+       *   * 'NonAnonymous' - Add a non-anonymous Single Onion Service. If this
+       *                      flag is present, tor must be in non-anonymous
+       *                      hidden service mode. If this flag is absent,
+       *                      tor must be in anonymous hidden service mode.
+       */
+      static const char *discard_flag = "DiscardPK";
+      static const char *detach_flag = "Detach";
+      static const char *max_s_close_flag = "MaxStreamsCloseCircuit";
+      static const char *basicauth_flag = "BasicAuth";
+      static const char *non_anonymous_flag = "NonAnonymous";
+
+      smartlist_t *flags = smartlist_new();
+      int bad = 0;
+
+      smartlist_split_string(flags, arg->value, ",", SPLIT_IGNORE_BLANK, 0);
+      if (smartlist_len(flags) < 1) {
+        control_write_endreply(conn, 512, "Invalid 'Flags' argument");
+        bad = 1;
+      }
+      SMARTLIST_FOREACH_BEGIN(flags, const char *, flag)
+      {
+        if (!strcasecmp(flag, discard_flag)) {
+          discard_pk = 1;
+        } else if (!strcasecmp(flag, detach_flag)) {
+          detach = 1;
+        } else if (!strcasecmp(flag, max_s_close_flag)) {
+          max_streams_close_circuit = 1;
+        } else if (!strcasecmp(flag, basicauth_flag)) {
+          auth_type = REND_BASIC_AUTH;
+        } else if (!strcasecmp(flag, non_anonymous_flag)) {
+          non_anonymous = 1;
+        } else {
+          control_printf_endreply(conn, 512, "Invalid 'Flags' argument: %s",
+                                  escaped(flag));
+          bad = 1;
+          break;
+        }
+      } SMARTLIST_FOREACH_END(flag);
+      SMARTLIST_FOREACH(flags, char *, cp, tor_free(cp));
+      smartlist_free(flags);
+      if (bad)
+        goto out;
+
+    } else if (!strcasecmp(arg->key, "ClientAuth")) {
+      char *err_msg = NULL;
+      int created = 0;
+      rend_authorized_client_t *client =
+        add_onion_helper_clientauth(arg->value,
+                                    &created, &err_msg);
+      if (!client) {
+        if (err_msg) {
+          connection_write_str_to_buf(err_msg, conn);
+          tor_free(err_msg);
+        }
+        goto out;
+      }
+
+      if (auth_clients != NULL) {
+        int bad = 0;
+        SMARTLIST_FOREACH_BEGIN(auth_clients, rend_authorized_client_t *, ac) {
+          if (strcmp(ac->client_name, client->client_name) == 0) {
+            bad = 1;
+            break;
+          }
+        } SMARTLIST_FOREACH_END(ac);
+        if (bad) {
+          control_write_endreply(conn, 512, "Duplicate name in ClientAuth");
+          rend_authorized_client_free(client);
+          goto out;
+        }
+      } else {
+        auth_clients = smartlist_new();
+        auth_created_clients = smartlist_new();
+      }
+      smartlist_add(auth_clients, client);
+      if (created) {
+        smartlist_add(auth_created_clients, client);
+      }
+    } else {
+      tor_assert_nonfatal_unreached();
+      goto out;
+    }
+  }
+  if (smartlist_len(port_cfgs) == 0) {
+    control_write_endreply(conn, 512, "Missing 'Port' argument");
+    goto out;
+  } else if (auth_type == REND_NO_AUTH && auth_clients != NULL) {
+    control_write_endreply(conn, 512, "No auth type specified");
+    goto out;
+  } else if (auth_type != REND_NO_AUTH && auth_clients == NULL) {
+    control_write_endreply(conn, 512, "No auth clients specified");
+    goto out;
+  } else if ((auth_type == REND_BASIC_AUTH &&
+              smartlist_len(auth_clients) > 512) ||
+             (auth_type == REND_STEALTH_AUTH &&
+              smartlist_len(auth_clients) > 16)) {
+    control_write_endreply(conn, 512, "Too many auth clients");
+    goto out;
+  } else if (non_anonymous != rend_service_non_anonymous_mode_enabled(
+                                                              get_options())) {
+    /* If we failed, and the non-anonymous flag is set, Tor must be in
+     * anonymous hidden service mode.
+     * The error message changes based on the current Tor config:
+     * 512 Tor is in anonymous hidden service mode
+     * 512 Tor is in non-anonymous hidden service mode
+     * (I've deliberately written them out in full here to aid searchability.)
+     */
+    control_printf_endreply(conn, 512,
+                            "Tor is in %sanonymous hidden service " "mode",
+                            non_anonymous ? "" : "non-");
+    goto out;
+  }
+
+  /* Parse the "keytype:keyblob" argument. */
+  int hs_version = 0;
+  add_onion_secret_key_t pk = { NULL };
+  const char *key_new_alg = NULL;
+  char *key_new_blob = NULL;
+  char *err_msg = NULL;
+
+  const char *onionkey = smartlist_get(args->args, 0);
+  if (add_onion_helper_keyarg(onionkey, discard_pk,
+                              &key_new_alg, &key_new_blob, &pk, &hs_version,
+                              &err_msg) < 0) {
+    if (err_msg) {
+      connection_write_str_to_buf(err_msg, conn);
+      tor_free(err_msg);
+    }
+    goto out;
+  }
+  tor_assert(!err_msg);
+
+  /* Hidden service version 3 don't have client authentication support so if
+   * ClientAuth was given, send back an error. */
+  if (hs_version == HS_VERSION_THREE && auth_clients) {
+    control_write_endreply(conn, 513, "ClientAuth not supported");
+    goto out;
+  }
+
+  /* Create the HS, using private key pk, client authentication auth_type,
+   * the list of auth_clients, and port config port_cfg.
+   * rend_service_add_ephemeral() will take ownership of pk and port_cfg,
+   * regardless of success/failure.
+   */
+  char *service_id = NULL;
+  int ret = add_onion_helper_add_service(hs_version, &pk, port_cfgs,
+                                         max_streams,
+                                         max_streams_close_circuit, auth_type,
+                                         auth_clients, &service_id);
+  port_cfgs = NULL; /* port_cfgs is now owned by the rendservice code. */
+  auth_clients = NULL; /* so is auth_clients */
+  switch (ret) {
+  case RSAE_OKAY:
+  {
+    if (detach) {
+      if (!detached_onion_services)
+        detached_onion_services = smartlist_new();
+      smartlist_add(detached_onion_services, service_id);
+    } else {
+      if (!conn->ephemeral_onion_services)
+        conn->ephemeral_onion_services = smartlist_new();
+      smartlist_add(conn->ephemeral_onion_services, service_id);
+    }
+
+    tor_assert(service_id);
+    control_printf_midreply(conn, 250, "ServiceID=%s", service_id);
+    if (key_new_alg) {
+      tor_assert(key_new_blob);
+      control_printf_midreply(conn, 250, "PrivateKey=%s:%s",
+                              key_new_alg, key_new_blob);
+    }
+    if (auth_created_clients) {
+      SMARTLIST_FOREACH(auth_created_clients, rend_authorized_client_t *, ac, {
+        char *encoded = rend_auth_encode_cookie(ac->descriptor_cookie,
+                                                auth_type);
+        tor_assert(encoded);
+        connection_printf_to_buf(conn, "250-ClientAuth=%s:%s\r\n",
+                                 ac->client_name, encoded);
+        memwipe(encoded, 0, strlen(encoded));
+        tor_free(encoded);
+      });
+    }
+
+    send_control_done(conn);
+    break;
+  }
+  case RSAE_BADPRIVKEY:
+    control_write_endreply(conn, 551, "Failed to generate onion address");
+    break;
+  case RSAE_ADDREXISTS:
+    control_write_endreply(conn, 550, "Onion address collision");
+    break;
+  case RSAE_BADVIRTPORT:
+    control_write_endreply(conn, 512, "Invalid VIRTPORT/TARGET");
+    break;
+  case RSAE_BADAUTH:
+    control_write_endreply(conn, 512, "Invalid client authorization");
+    break;
+  case RSAE_INTERNAL: /* FALLSTHROUGH */
+  default:
+    control_write_endreply(conn, 551, "Failed to add Onion Service");
+  }
+  if (key_new_blob) {
+    memwipe(key_new_blob, 0, strlen(key_new_blob));
+    tor_free(key_new_blob);
+  }
+
+ out:
+  if (port_cfgs) {
+    SMARTLIST_FOREACH(port_cfgs, rend_service_port_config_t*, p,
+                      rend_service_port_config_free(p));
+    smartlist_free(port_cfgs);
+  }
+
+  if (auth_clients) {
+    SMARTLIST_FOREACH(auth_clients, rend_authorized_client_t *, ac,
+                      rend_authorized_client_free(ac));
+    smartlist_free(auth_clients);
+  }
+  if (auth_created_clients) {
+    // Do not free entries; they are the same as auth_clients
+    smartlist_free(auth_created_clients);
+  }
+  return 0;
+}
+
+/** Helper function to handle parsing the KeyType:KeyBlob argument to the
+ * ADD_ONION command. Return a new crypto_pk_t and if a new key was generated
+ * and the private key not discarded, the algorithm and serialized private key,
+ * or NULL and an optional control protocol error message on failure.  The
+ * caller is responsible for freeing the returned key_new_blob and err_msg.
+ *
+ * Note: The error messages returned are deliberately vague to avoid echoing
+ * key material.
+ */
+STATIC int
+add_onion_helper_keyarg(const char *arg, int discard_pk,
+                        const char **key_new_alg_out, char **key_new_blob_out,
+                        add_onion_secret_key_t *decoded_key, int *hs_version,
+                        char **err_msg_out)
+{
+  smartlist_t *key_args = smartlist_new();
+  crypto_pk_t *pk = NULL;
+  const char *key_new_alg = NULL;
+  char *key_new_blob = NULL;
+  char *err_msg = NULL;
+  int ret = -1;
+
+  smartlist_split_string(key_args, arg, ":", SPLIT_IGNORE_BLANK, 0);
+  if (smartlist_len(key_args) != 2) {
+    err_msg = tor_strdup("512 Invalid key type/blob\r\n");
+    goto err;
+  }
+
+  /* The format is "KeyType:KeyBlob". */
+  static const char *key_type_new = "NEW";
+  static const char *key_type_best = "BEST";
+  static const char *key_type_rsa1024 = "RSA1024";
+  static const char *key_type_ed25519_v3 = "ED25519-V3";
+
+  const char *key_type = smartlist_get(key_args, 0);
+  const char *key_blob = smartlist_get(key_args, 1);
+
+  if (!strcasecmp(key_type_rsa1024, key_type)) {
+    /* "RSA:<Base64 Blob>" - Loading a pre-existing RSA1024 key. */
+    pk = crypto_pk_base64_decode_private(key_blob, strlen(key_blob));
+    if (!pk) {
+      err_msg = tor_strdup("512 Failed to decode RSA key\r\n");
+      goto err;
+    }
+    if (crypto_pk_num_bits(pk) != PK_BYTES*8) {
+      crypto_pk_free(pk);
+      err_msg = tor_strdup("512 Invalid RSA key size\r\n");
+      goto err;
+    }
+    decoded_key->v2 = pk;
+    *hs_version = HS_VERSION_TWO;
+  } else if (!strcasecmp(key_type_ed25519_v3, key_type)) {
+    /* "ED25519-V3:<Base64 Blob>" - Loading a pre-existing ed25519 key. */
+    ed25519_secret_key_t *sk = tor_malloc_zero(sizeof(*sk));
+    if (base64_decode((char *) sk->seckey, sizeof(sk->seckey), key_blob,
+                      strlen(key_blob)) != sizeof(sk->seckey)) {
+      tor_free(sk);
+      err_msg = tor_strdup("512 Failed to decode ED25519-V3 key\r\n");
+      goto err;
+    }
+    decoded_key->v3 = sk;
+    *hs_version = HS_VERSION_THREE;
+  } else if (!strcasecmp(key_type_new, key_type)) {
+    /* "NEW:<Algorithm>" - Generating a new key, blob as algorithm. */
+    if (!strcasecmp(key_type_rsa1024, key_blob) ||
+        !strcasecmp(key_type_best, key_blob)) {
+      /* "RSA1024", RSA 1024 bit, also currently "BEST" by default. */
+      pk = crypto_pk_new();
+      if (crypto_pk_generate_key(pk)) {
+        tor_asprintf(&err_msg, "551 Failed to generate %s key\r\n",
+                     key_type_rsa1024);
+        goto err;
+      }
+      if (!discard_pk) {
+        if (crypto_pk_base64_encode_private(pk, &key_new_blob)) {
+          crypto_pk_free(pk);
+          tor_asprintf(&err_msg, "551 Failed to encode %s key\r\n",
+                       key_type_rsa1024);
+          goto err;
+        }
+        key_new_alg = key_type_rsa1024;
+      }
+      decoded_key->v2 = pk;
+      *hs_version = HS_VERSION_TWO;
+    } else if (!strcasecmp(key_type_ed25519_v3, key_blob)) {
+      ed25519_secret_key_t *sk = tor_malloc_zero(sizeof(*sk));
+      if (ed25519_secret_key_generate(sk, 1) < 0) {
+        tor_free(sk);
+        tor_asprintf(&err_msg, "551 Failed to generate %s key\r\n",
+                     key_type_ed25519_v3);
+        goto err;
+      }
+      if (!discard_pk) {
+        ssize_t len = base64_encode_size(sizeof(sk->seckey), 0) + 1;
+        key_new_blob = tor_malloc_zero(len);
+        if (base64_encode(key_new_blob, len, (const char *) sk->seckey,
+                          sizeof(sk->seckey), 0) != (len - 1)) {
+          tor_free(sk);
+          tor_free(key_new_blob);
+          tor_asprintf(&err_msg, "551 Failed to encode %s key\r\n",
+                       key_type_ed25519_v3);
+          goto err;
+        }
+        key_new_alg = key_type_ed25519_v3;
+      }
+      decoded_key->v3 = sk;
+      *hs_version = HS_VERSION_THREE;
+    } else {
+      err_msg = tor_strdup("513 Invalid key type\r\n");
+      goto err;
+    }
+  } else {
+    err_msg = tor_strdup("513 Invalid key type\r\n");
+    goto err;
+  }
+
+  /* Succeeded in loading or generating a private key. */
+  ret = 0;
+
+ err:
+  SMARTLIST_FOREACH(key_args, char *, cp, {
+    memwipe(cp, 0, strlen(cp));
+    tor_free(cp);
+  });
+  smartlist_free(key_args);
+
+  if (err_msg_out) {
+    *err_msg_out = err_msg;
+  } else {
+    tor_free(err_msg);
+  }
+  *key_new_alg_out = key_new_alg;
+  *key_new_blob_out = key_new_blob;
+
+  return ret;
+}
+
+/** Helper function to handle parsing a ClientAuth argument to the
+ * ADD_ONION command.  Return a new rend_authorized_client_t, or NULL
+ * and an optional control protocol error message on failure.  The
+ * caller is responsible for freeing the returned auth_client and err_msg.
+ *
+ * If 'created' is specified, it will be set to 1 when a new cookie has
+ * been generated.
+ */
+STATIC rend_authorized_client_t *
+add_onion_helper_clientauth(const char *arg, int *created, char **err_msg)
+{
+  int ok = 0;
+
+  tor_assert(arg);
+  tor_assert(created);
+  tor_assert(err_msg);
+  *err_msg = NULL;
+
+  smartlist_t *auth_args = smartlist_new();
+  rend_authorized_client_t *client =
+    tor_malloc_zero(sizeof(rend_authorized_client_t));
+  smartlist_split_string(auth_args, arg, ":", 0, 0);
+  if (smartlist_len(auth_args) < 1 || smartlist_len(auth_args) > 2) {
+    *err_msg = tor_strdup("512 Invalid ClientAuth syntax\r\n");
+    goto err;
+  }
+  client->client_name = tor_strdup(smartlist_get(auth_args, 0));
+  if (smartlist_len(auth_args) == 2) {
+    char *decode_err_msg = NULL;
+    if (rend_auth_decode_cookie(smartlist_get(auth_args, 1),
+                                client->descriptor_cookie,
+                                NULL, &decode_err_msg) < 0) {
+      tor_assert(decode_err_msg);
+      tor_asprintf(err_msg, "512 %s\r\n", decode_err_msg);
+      tor_free(decode_err_msg);
+      goto err;
+    }
+    *created = 0;
+  } else {
+    crypto_rand((char *) client->descriptor_cookie, REND_DESC_COOKIE_LEN);
+    *created = 1;
+  }
+
+  if (!rend_valid_client_name(client->client_name)) {
+    *err_msg = tor_strdup("512 Invalid name in ClientAuth\r\n");
+    goto err;
+  }
+
+  ok = 1;
+ err:
+  SMARTLIST_FOREACH(auth_args, char *, item, tor_free(item));
+  smartlist_free(auth_args);
+  if (!ok) {
+    rend_authorized_client_free(client);
+    client = NULL;
+  }
+  return client;
+}
+
+static const control_cmd_syntax_t del_onion_syntax = {
+  .min_args = 1, .max_args = 1,
+};
+
+/** Called when we get a DEL_ONION command; parse the body, and remove
+ * the existing ephemeral Onion Service. */
+static int
+handle_control_del_onion(control_connection_t *conn,
+                         const control_cmd_args_t *cmd_args)
+{
+  int hs_version = 0;
+  smartlist_t *args = cmd_args->args;
+  tor_assert(smartlist_len(args) == 1);
+
+  const char *service_id = smartlist_get(args, 0);
+  if (rend_valid_v2_service_id(service_id)) {
+    hs_version = HS_VERSION_TWO;
+  } else if (hs_address_is_valid(service_id)) {
+    hs_version = HS_VERSION_THREE;
+  } else {
+    control_write_endreply(conn, 512, "Malformed Onion Service id");
+    goto out;
+  }
+
+  /* Determine if the onion service belongs to this particular control
+   * connection, or if it is in the global list of detached services.  If it
+   * is in neither, either the service ID is invalid in some way, or it
+   * explicitly belongs to a different control connection, and an error
+   * should be returned.
+   */
+  smartlist_t *services[2] = {
+    conn->ephemeral_onion_services,
+    detached_onion_services
+  };
+  smartlist_t *onion_services = NULL;
+  int idx = -1;
+  for (size_t i = 0; i < ARRAY_LENGTH(services); i++) {
+    idx = smartlist_string_pos(services[i], service_id);
+    if (idx != -1) {
+      onion_services = services[i];
+      break;
+    }
+  }
+  if (onion_services == NULL) {
+    control_write_endreply(conn, 552, "Unknown Onion Service id");
+  } else {
+    int ret = -1;
+    switch (hs_version) {
+    case HS_VERSION_TWO:
+      ret = rend_service_del_ephemeral(service_id);
+      break;
+    case HS_VERSION_THREE:
+      ret = hs_service_del_ephemeral(service_id);
+      break;
+    default:
+      /* The ret value will be -1 thus hitting the warning below. This should
+       * never happen because of the check at the start of the function. */
+      break;
+    }
+    if (ret < 0) {
+      /* This should *NEVER* fail, since the service is on either the
+       * per-control connection list, or the global one.
+       */
+      log_warn(LD_BUG, "Failed to remove Onion Service %s.",
+               escaped(service_id));
+      tor_fragile_assert();
+    }
+
+    /* Remove/scrub the service_id from the appropriate list. */
+    char *cp = smartlist_get(onion_services, idx);
+    smartlist_del(onion_services, idx);
+    memwipe(cp, 0, strlen(cp));
+    tor_free(cp);
+
+    send_control_done(conn);
+  }
+
+ out:
+  return 0;
+}
+
+static const control_cmd_syntax_t obsolete_syntax = {
+  .max_args = UINT_MAX
+};
+
+/**
+ * Called when we get an obsolete command: tell the controller that it is
+ * obsolete.
+ */
+static int
+handle_control_obsolete(control_connection_t *conn,
+                        const control_cmd_args_t *args)
+{
+  (void)args;
+  char *command = tor_strdup(conn->current_cmd);
+  tor_strupper(command);
+  control_printf_endreply(conn, 511, "%s is obsolete.", command);
+  tor_free(command);
+  return 0;
+}
+
+/**
+ * Function pointer to a handler function for a controller command.
+ **/
+typedef int (*handler_fn_t) (control_connection_t *conn,
+                             const control_cmd_args_t *args);
+
+/**
+ * Definition for a controller command.
+ */
+typedef struct control_cmd_def_t {
+  /**
+   * The name of the command. If the command is multiline, the name must
+   * begin with "+".  This is not case-sensitive. */
+  const char *name;
+  /**
+   * A function to execute the command.
+   */
+  handler_fn_t handler;
+  /**
+   * Zero or more CMD_FL_* flags, or'd together.
+   */
+  unsigned flags;
+  /**
+   * For parsed command: a syntax description.
+   */
+  const control_cmd_syntax_t *syntax;
+} control_cmd_def_t;
+
+/**
+ * Indicates that the command's arguments are sensitive, and should be
+ * memwiped after use.
+ */
+#define CMD_FL_WIPE (1u<<0)
+
+/** Macro: declare a command with a one-line argument, a given set of flags,
+ * and a syntax definition.
+ **/
+#define ONE_LINE(name, flags)                                   \
+  {                                                             \
+    #name,                                                      \
+      handle_control_ ##name,                                   \
+      flags,                                                    \
+      &name##_syntax,                                           \
+   }
+
+/**
+ * Macro: declare a command with a multi-line argument and a given set of
+ * flags.
+ **/
+#define MULTLINE(name, flags)                                   \
+  { "+"#name,                                                   \
+      handle_control_ ##name,                                   \
+      flags,                                                    \
+      &name##_syntax                                            \
+  }
+
+/**
+ * Macro: declare an obsolete command. (Obsolete commands give a different
+ * error than non-existent ones.)
+ **/
+#define OBSOLETE(name)                          \
+  { #name,                                      \
+      handle_control_obsolete,                  \
+      0,                                        \
+      &obsolete_syntax,                         \
+  }
+
+/**
+ * An array defining all the recognized controller commands.
+ **/
+static const control_cmd_def_t CONTROL_COMMANDS[] =
+{
+  ONE_LINE(setconf, 0),
+  ONE_LINE(resetconf, 0),
+  ONE_LINE(getconf, 0),
+  MULTLINE(loadconf, 0),
+  ONE_LINE(setevents, 0),
+  ONE_LINE(authenticate, CMD_FL_WIPE),
+  ONE_LINE(saveconf, 0),
+  ONE_LINE(signal, 0),
+  ONE_LINE(takeownership, 0),
+  ONE_LINE(dropownership, 0),
+  ONE_LINE(mapaddress, 0),
+  ONE_LINE(getinfo, 0),
+  ONE_LINE(extendcircuit, 0),
+  ONE_LINE(setcircuitpurpose, 0),
+  OBSOLETE(setrouterpurpose),
+  ONE_LINE(attachstream, 0),
+  MULTLINE(postdescriptor, 0),
+  ONE_LINE(redirectstream, 0),
+  ONE_LINE(closestream, 0),
+  ONE_LINE(closecircuit, 0),
+  ONE_LINE(usefeature, 0),
+  ONE_LINE(resolve, 0),
+  ONE_LINE(protocolinfo, 0),
+  ONE_LINE(authchallenge, CMD_FL_WIPE),
+  ONE_LINE(dropguards, 0),
+  ONE_LINE(hsfetch, 0),
+  MULTLINE(hspost, 0),
+  ONE_LINE(add_onion, CMD_FL_WIPE),
+  ONE_LINE(del_onion, CMD_FL_WIPE),
+};
+
+/**
+ * The number of entries in CONTROL_COMMANDS.
+ **/
+static const size_t N_CONTROL_COMMANDS = ARRAY_LENGTH(CONTROL_COMMANDS);
+
+/**
+ * Run a single control command, as defined by a control_cmd_def_t,
+ * with a given set of arguments.
+ */
+static int
+handle_single_control_command(const control_cmd_def_t *def,
+                              control_connection_t *conn,
+                              uint32_t cmd_data_len,
+                              char *args)
+{
+  int rv = 0;
+
+  control_cmd_args_t *parsed_args;
+  char *err=NULL;
+  tor_assert(def->syntax);
+  parsed_args = control_cmd_parse_args(conn->current_cmd,
+                                       def->syntax,
+                                       cmd_data_len, args,
+                                       &err);
+  if (!parsed_args) {
+    control_printf_endreply(conn, 512, "Bad arguments to %s: %s",
+                            conn->current_cmd, err?err:"");
+    tor_free(err);
+  } else {
+    if (BUG(err))
+      tor_free(err);
+    if (def->handler(conn, parsed_args))
+      rv = 0;
+
+    if (def->flags & CMD_FL_WIPE)
+      control_cmd_args_wipe(parsed_args);
+
+    control_cmd_args_free(parsed_args);
+  }
+
+  if (def->flags & CMD_FL_WIPE)
+    memwipe(args, 0, cmd_data_len);
+
+  return rv;
+}
+
+/**
+ * Run a given controller command, as selected by the current_cmd field of
+ * <b>conn</b>.
+ */
+int
+handle_control_command(control_connection_t *conn,
+                       uint32_t cmd_data_len,
+                       char *args)
+{
+  tor_assert(conn);
+  tor_assert(args);
+  tor_assert(args[cmd_data_len] == '\0');
+
+  for (unsigned i = 0; i < N_CONTROL_COMMANDS; ++i) {
+    const control_cmd_def_t *def = &CONTROL_COMMANDS[i];
+    if (!strcasecmp(conn->current_cmd, def->name)) {
+      return handle_single_control_command(def, conn, cmd_data_len, args);
+    }
+  }
+
+  control_printf_endreply(conn, 510, "Unrecognized command \"%s\"",
+                          conn->current_cmd);
+
+  return 0;
+}
+
+void
+control_cmd_free_all(void)
+{
+  if (detached_onion_services) { /* Free the detached onion services */
+    SMARTLIST_FOREACH(detached_onion_services, char *, cp, tor_free(cp));
+    smartlist_free(detached_onion_services);
+  }
+}
diff --git a/src/feature/control/control_cmd.h b/src/feature/control/control_cmd.h
new file mode 100644
index 000000000..5c3d1a1ce
--- /dev/null
+++ b/src/feature/control/control_cmd.h
@@ -0,0 +1,112 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_cmd.h
+ * \brief Header file for control_cmd.c.
+ **/
+
+#ifndef TOR_CONTROL_CMD_H
+#define TOR_CONTROL_CMD_H
+
+#include "lib/malloc/malloc.h"
+
+int handle_control_command(control_connection_t *conn,
+                           uint32_t cmd_data_len,
+                           char *args);
+void control_cmd_free_all(void);
+
+typedef struct control_cmd_args_t control_cmd_args_t;
+void control_cmd_args_free_(control_cmd_args_t *args);
+void control_cmd_args_wipe(control_cmd_args_t *args);
+
+#define control_cmd_args_free(v) \
+  FREE_AND_NULL(control_cmd_args_t, control_cmd_args_free_, (v))
+
+/**
+ * Definition for the syntax of a controller command, as parsed by
+ * control_cmd_parse_args.
+ *
+ * WORK IN PROGRESS: This structure is going to get more complex as this
+ * branch goes on.
+ **/
+typedef struct control_cmd_syntax_t {
+  /**
+   * Lowest number of positional arguments that this command accepts.
+   * 0 for "it's okay not to have positional arguments."
+   **/
+  unsigned int min_args;
+  /**
+   * Highest number of positional arguments that this command accepts.
+   * UINT_MAX for no limit.
+   **/
+  unsigned int max_args;
+  /**
+   * If true, we should parse options after the positional arguments
+   * as a set of unordered flags and key=value arguments.
+   *
+   * Requires that max_args is not UINT_MAX.
+   **/
+  bool accept_keywords;
+  /**
+   * If accept_keywords is true, then only the keywords listed in this
+   * (NULL-terminated) array are valid keywords for this command.
+   **/
+  const char **allowed_keywords;
+  /**
+   * If accept_keywords is true, this option is passed to kvline_parse() as
+   * its flags.
+   **/
+  unsigned kvline_flags;
+  /**
+   * True iff this command wants to be followed by a multiline object.
+   **/
+  bool want_cmddata;
+  /**
+   * True iff this command needs access to the raw body of the input.
+   *
+   * This should not be needed for pure commands; it is purely a legacy
+   * option.
+   **/
+  bool store_raw_body;
+} control_cmd_syntax_t;
+
+#ifdef CONTROL_CMD_PRIVATE
+#include "lib/crypt_ops/crypto_ed25519.h"
+
+/* ADD_ONION secret key to create an ephemeral service. The command supports
+ * multiple versions so this union stores the key and passes it to the HS
+ * subsystem depending on the requested version. */
+typedef union add_onion_secret_key_t {
+  /* Hidden service v2 secret key. */
+  crypto_pk_t *v2;
+  /* Hidden service v3 secret key. */
+  ed25519_secret_key_t *v3;
+} add_onion_secret_key_t;
+
+STATIC int add_onion_helper_keyarg(const char *arg, int discard_pk,
+                                   const char **key_new_alg_out,
+                                   char **key_new_blob_out,
+                                   add_onion_secret_key_t *decoded_key,
+                                   int *hs_version, char **err_msg_out);
+
+STATIC rend_authorized_client_t *add_onion_helper_clientauth(const char *arg,
+                                   int *created, char **err_msg_out);
+
+STATIC control_cmd_args_t *control_cmd_parse_args(
+                                   const char *command,
+                                   const control_cmd_syntax_t *syntax,
+                                   size_t body_len,
+                                   const char *body,
+                                   char **error_out);
+
+#endif /* defined(CONTROL_CMD_PRIVATE) */
+
+#ifdef CONTROL_MODULE_PRIVATE
+smartlist_t * get_detached_onion_services(void);
+#endif /* defined(CONTROL_MODULE_PRIVATE) */
+
+#endif /* !defined(TOR_CONTROL_CMD_H) */
diff --git a/src/feature/control/control_cmd_args_st.h b/src/feature/control/control_cmd_args_st.h
new file mode 100644
index 000000000..8d7a4f55b
--- /dev/null
+++ b/src/feature/control/control_cmd_args_st.h
@@ -0,0 +1,52 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_cmd_args_st.h
+ * \brief Definition for control_cmd_args_t
+ **/
+
+#ifndef TOR_CONTROL_CMD_ST_H
+#define TOR_CONTROL_CMD_ST_H
+
+struct smartlist_t;
+struct config_line_t;
+
+/**
+ * Parsed arguments for a control command.
+ *
+ * WORK IN PROGRESS: This structure is going to get more complex as this
+ * branch goes on.
+ **/
+struct control_cmd_args_t {
+  /**
+   * The command itself, as provided by the controller.  Not owned by this
+   * structure.
+   **/
+  const char *command;
+  /**
+   * Positional arguments to the command.
+   **/
+  struct smartlist_t *args;
+  /**
+   * Keyword arguments to the command.
+   **/
+  struct config_line_t *kwargs;
+  /**
+   * Number of bytes in <b>cmddata</b>; 0 if <b>cmddata</b> is not set.
+   **/
+  size_t cmddata_len;
+  /**
+   * A multiline object passed with this command.
+   **/
+  char *cmddata;
+  /**
+   * If set, a nul-terminated string containing the raw unparsed arguments.
+   **/
+  const char *raw_body;
+};
+
+#endif /* !defined(TOR_CONTROL_CMD_ST_H) */
diff --git a/src/feature/control/control_connection_st.h b/src/feature/control/control_connection_st.h
index 177a91625..c9164f03b 100644
--- a/src/feature/control/control_connection_st.h
+++ b/src/feature/control/control_connection_st.h
@@ -40,7 +40,8 @@ struct control_connection_t {
   /** A control command that we're reading from the inbuf, but which has not
    * yet arrived completely. */
   char *incoming_cmd;
+  /** The control command that we are currently processing. */
+  char *current_cmd;
 };
 
-#endif
-
+#endif /* !defined(CONTROL_CONNECTION_ST_H) */
diff --git a/src/feature/control/control_events.c b/src/feature/control/control_events.c
new file mode 100644
index 000000000..9e0966ca5
--- /dev/null
+++ b/src/feature/control/control_events.c
@@ -0,0 +1,2318 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_events.c
+ * \brief Implement the event-reporting part of the controller API.
+ **/
+
+#define CONTROL_MODULE_PRIVATE
+#define CONTROL_EVENTS_PRIVATE
+#define OCIRC_EVENT_PRIVATE
+
+#include "core/or/or.h"
+#include "app/config/config.h"
+#include "core/mainloop/connection.h"
+#include "core/mainloop/mainloop.h"
+#include "core/or/channeltls.h"
+#include "core/or/circuitlist.h"
+#include "core/or/command.h"
+#include "core/or/connection_edge.h"
+#include "core/or/connection_or.h"
+#include "core/or/reasons.h"
+#include "feature/control/control.h"
+#include "feature/control/control_events.h"
+#include "feature/control/control_fmt.h"
+#include "feature/control/control_proto.h"
+#include "feature/dircommon/directory.h"
+#include "feature/nodelist/networkstatus.h"
+#include "feature/nodelist/nodelist.h"
+#include "feature/nodelist/routerinfo.h"
+
+#include "feature/control/control_connection_st.h"
+#include "core/or/entry_connection_st.h"
+#include "feature/nodelist/networkstatus_st.h"
+#include "core/or/or_connection_st.h"
+#include "core/or/or_circuit_st.h"
+#include "core/or/origin_circuit_st.h"
+
+#include "lib/evloop/compat_libevent.h"
+
+static void flush_queued_events_cb(mainloop_event_t *event, void *arg);
+static void control_get_bytes_rw_last_sec(uint64_t *r, uint64_t *w);
+
+/** Yield true iff <b>s</b> is the state of a control_connection_t that has
+ * finished authentication and is accepting commands. */
+#define STATE_IS_OPEN(s) ((s) == CONTROL_CONN_STATE_OPEN)
+
+/** An event mask of all the events that any controller is interested in
+ * receiving. */
+static event_mask_t global_event_mask = 0;
+
+/** True iff we have disabled log messages from being sent to the controller */
+static int disable_log_messages = 0;
+
+/** Macro: true if any control connection is interested in events of type
+ * <b>e</b>. */
+#define EVENT_IS_INTERESTING(e) \
+  (!! (global_event_mask & EVENT_MASK_(e)))
+
+/** Macro: true if any event from the bitfield 'e' is interesting. */
+#define ANY_EVENT_IS_INTERESTING(e) \
+  (!! (global_event_mask & (e)))
+
+static void send_control_event_impl(uint16_t event,
+                                    const char *format, va_list ap)
+  CHECK_PRINTF(2,0);
+static int control_event_status(int type, int severity, const char *format,
+                                va_list args)
+  CHECK_PRINTF(3,0);
+
+static void send_control_event(uint16_t event,
+                               const char *format, ...)
+  CHECK_PRINTF(2,3);
+
+/** Table mapping event values to their names.  Used to implement SETEVENTS
+ * and GETINFO events/names, and to keep they in sync. */
+const struct control_event_t control_event_table[] = {
+  { EVENT_CIRCUIT_STATUS, "CIRC" },
+  { EVENT_CIRCUIT_STATUS_MINOR, "CIRC_MINOR" },
+  { EVENT_STREAM_STATUS, "STREAM" },
+  { EVENT_OR_CONN_STATUS, "ORCONN" },
+  { EVENT_BANDWIDTH_USED, "BW" },
+  { EVENT_DEBUG_MSG, "DEBUG" },
+  { EVENT_INFO_MSG, "INFO" },
+  { EVENT_NOTICE_MSG, "NOTICE" },
+  { EVENT_WARN_MSG, "WARN" },
+  { EVENT_ERR_MSG, "ERR" },
+  { EVENT_NEW_DESC, "NEWDESC" },
+  { EVENT_ADDRMAP, "ADDRMAP" },
+  { EVENT_DESCCHANGED, "DESCCHANGED" },
+  { EVENT_NS, "NS" },
+  { EVENT_STATUS_GENERAL, "STATUS_GENERAL" },
+  { EVENT_STATUS_CLIENT, "STATUS_CLIENT" },
+  { EVENT_STATUS_SERVER, "STATUS_SERVER" },
+  { EVENT_GUARD, "GUARD" },
+  { EVENT_STREAM_BANDWIDTH_USED, "STREAM_BW" },
+  { EVENT_CLIENTS_SEEN, "CLIENTS_SEEN" },
+  { EVENT_NEWCONSENSUS, "NEWCONSENSUS" },
+  { EVENT_BUILDTIMEOUT_SET, "BUILDTIMEOUT_SET" },
+  { EVENT_GOT_SIGNAL, "SIGNAL" },
+  { EVENT_CONF_CHANGED, "CONF_CHANGED"},
+  { EVENT_CONN_BW, "CONN_BW" },
+  { EVENT_CELL_STATS, "CELL_STATS" },
+  { EVENT_CIRC_BANDWIDTH_USED, "CIRC_BW" },
+  { EVENT_TRANSPORT_LAUNCHED, "TRANSPORT_LAUNCHED" },
+  { EVENT_HS_DESC, "HS_DESC" },
+  { EVENT_HS_DESC_CONTENT, "HS_DESC_CONTENT" },
+  { EVENT_NETWORK_LIVENESS, "NETWORK_LIVENESS" },
+  { 0, NULL },
+};
+
+/** Given a log severity, return the corresponding control event code. */
+static inline int
+log_severity_to_event(int severity)
+{
+  switch (severity) {
+    case LOG_DEBUG: return EVENT_DEBUG_MSG;
+    case LOG_INFO: return EVENT_INFO_MSG;
+    case LOG_NOTICE: return EVENT_NOTICE_MSG;
+    case LOG_WARN: return EVENT_WARN_MSG;
+    case LOG_ERR: return EVENT_ERR_MSG;
+    default: return -1;
+  }
+}
+
+/** Helper: clear bandwidth counters of all origin circuits. */
+static void
+clear_circ_bw_fields(void)
+{
+  origin_circuit_t *ocirc;
+  SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
+    if (!CIRCUIT_IS_ORIGIN(circ))
+      continue;
+    ocirc = TO_ORIGIN_CIRCUIT(circ);
+    ocirc->n_written_circ_bw = ocirc->n_read_circ_bw = 0;
+    ocirc->n_overhead_written_circ_bw = ocirc->n_overhead_read_circ_bw = 0;
+    ocirc->n_delivered_written_circ_bw = ocirc->n_delivered_read_circ_bw = 0;
+  }
+  SMARTLIST_FOREACH_END(circ);
+}
+
+/** Set <b>global_event_mask*</b> to the bitwise OR of each live control
+ * connection's event_mask field. */
+void
+control_update_global_event_mask(void)
+{
+  smartlist_t *conns = get_connection_array();
+  event_mask_t old_mask, new_mask;
+  old_mask = global_event_mask;
+  int any_old_per_sec_events = control_any_per_second_event_enabled();
+
+  global_event_mask = 0;
+  SMARTLIST_FOREACH(conns, connection_t *, _conn,
+  {
+    if (_conn->type == CONN_TYPE_CONTROL &&
+        STATE_IS_OPEN(_conn->state)) {
+      control_connection_t *conn = TO_CONTROL_CONN(_conn);
+      global_event_mask |= conn->event_mask;
+    }
+  });
+
+  new_mask = global_event_mask;
+
+  /* Handle the aftermath.  Set up the log callback to tell us only what
+   * we want to hear...*/
+  control_adjust_event_log_severity();
+
+  /* Macro: true if ev was false before and is true now. */
+#define NEWLY_ENABLED(ev) \
+  (! (old_mask & (ev)) && (new_mask & (ev)))
+
+  /* ...then, if we've started logging stream or circ bw, clear the
+   * appropriate fields. */
+  if (NEWLY_ENABLED(EVENT_STREAM_BANDWIDTH_USED)) {
+    SMARTLIST_FOREACH(conns, connection_t *, conn,
+    {
+      if (conn->type == CONN_TYPE_AP) {
+        edge_connection_t *edge_conn = TO_EDGE_CONN(conn);
+        edge_conn->n_written = edge_conn->n_read = 0;
+      }
+    });
+  }
+  if (NEWLY_ENABLED(EVENT_CIRC_BANDWIDTH_USED)) {
+    clear_circ_bw_fields();
+  }
+  if (NEWLY_ENABLED(EVENT_BANDWIDTH_USED)) {
+    uint64_t r, w;
+    control_get_bytes_rw_last_sec(&r, &w);
+  }
+  if (any_old_per_sec_events != control_any_per_second_event_enabled()) {
+    rescan_periodic_events(get_options());
+  }
+
+#undef NEWLY_ENABLED
+}
+
+/** Given a control event code for a message event, return the corresponding
+ * log severity. */
+static inline int
+event_to_log_severity(int event)
+{
+  switch (event) {
+    case EVENT_DEBUG_MSG: return LOG_DEBUG;
+    case EVENT_INFO_MSG: return LOG_INFO;
+    case EVENT_NOTICE_MSG: return LOG_NOTICE;
+    case EVENT_WARN_MSG: return LOG_WARN;
+    case EVENT_ERR_MSG: return LOG_ERR;
+    default: return -1;
+  }
+}
+
+/** Adjust the log severities that result in control_event_logmsg being called
+ * to match the severity of log messages that any controllers are interested
+ * in. */
+void
+control_adjust_event_log_severity(void)
+{
+  int i;
+  int min_log_event=EVENT_ERR_MSG, max_log_event=EVENT_DEBUG_MSG;
+
+  for (i = EVENT_DEBUG_MSG; i <= EVENT_ERR_MSG; ++i) {
+    if (EVENT_IS_INTERESTING(i)) {
+      min_log_event = i;
+      break;
+    }
+  }
+  for (i = EVENT_ERR_MSG; i >= EVENT_DEBUG_MSG; --i) {
+    if (EVENT_IS_INTERESTING(i)) {
+      max_log_event = i;
+      break;
+    }
+  }
+  if (EVENT_IS_INTERESTING(EVENT_STATUS_GENERAL)) {
+    if (min_log_event > EVENT_NOTICE_MSG)
+      min_log_event = EVENT_NOTICE_MSG;
+    if (max_log_event < EVENT_ERR_MSG)
+      max_log_event = EVENT_ERR_MSG;
+  }
+  if (min_log_event <= max_log_event)
+    change_callback_log_severity(event_to_log_severity(min_log_event),
+                                 event_to_log_severity(max_log_event),
+                                 control_event_logmsg);
+  else
+    change_callback_log_severity(LOG_ERR, LOG_ERR,
+                                 control_event_logmsg);
+}
+
+/** Return true iff the event with code <b>c</b> is being sent to any current
+ * control connection.  This is useful if the amount of work needed to prepare
+ * to call the appropriate control_event_...() function is high.
+ */
+int
+control_event_is_interesting(int event)
+{
+  return EVENT_IS_INTERESTING(event);
+}
+
+/** Return true if any event that needs to fire once a second is enabled. */
+int
+control_any_per_second_event_enabled(void)
+{
+  return ANY_EVENT_IS_INTERESTING(
+      EVENT_MASK_(EVENT_BANDWIDTH_USED) |
+      EVENT_MASK_(EVENT_CELL_STATS) |
+      EVENT_MASK_(EVENT_CIRC_BANDWIDTH_USED) |
+      EVENT_MASK_(EVENT_CONN_BW) |
+      EVENT_MASK_(EVENT_STREAM_BANDWIDTH_USED)
+  );
+}
+
+/* The value of 'get_bytes_read()' the previous time that
+ * control_get_bytes_rw_last_sec() as called. */
+static uint64_t stats_prev_n_read = 0;
+/* The value of 'get_bytes_written()' the previous time that
+ * control_get_bytes_rw_last_sec() as called. */
+static uint64_t stats_prev_n_written = 0;
+
+/**
+ * Set <b>n_read</b> and <b>n_written</b> to the total number of bytes read
+ * and written by Tor since the last call to this function.
+ *
+ * Call this only from the main thread.
+ */
+static void
+control_get_bytes_rw_last_sec(uint64_t *n_read,
+                              uint64_t *n_written)
+{
+  const uint64_t stats_n_bytes_read = get_bytes_read();
+  const uint64_t stats_n_bytes_written = get_bytes_written();
+
+  *n_read = stats_n_bytes_read - stats_prev_n_read;
+  *n_written = stats_n_bytes_written - stats_prev_n_written;
+  stats_prev_n_read = stats_n_bytes_read;
+  stats_prev_n_written = stats_n_bytes_written;
+}
+
+/**
+ * Run all the controller events (if any) that are scheduled to trigger once
+ * per second.
+ */
+void
+control_per_second_events(void)
+{
+  if (!control_any_per_second_event_enabled())
+    return;
+
+  uint64_t bytes_read, bytes_written;
+  control_get_bytes_rw_last_sec(&bytes_read, &bytes_written);
+  control_event_bandwidth_used((uint32_t)bytes_read,(uint32_t)bytes_written);
+
+  control_event_stream_bandwidth_used();
+  control_event_conn_bandwidth_used();
+  control_event_circ_bandwidth_used();
+  control_event_circuit_cell_stats();
+}
+
+/** Represents an event that's queued to be sent to one or more
+ * controllers. */
+typedef struct queued_event_s {
+  uint16_t event;
+  char *msg;
+} queued_event_t;
+
+/** Pointer to int. If this is greater than 0, we don't allow new events to be
+ * queued. */
+static tor_threadlocal_t block_event_queue_flag;
+
+/** Holds a smartlist of queued_event_t objects that may need to be sent
+ * to one or more controllers */
+static smartlist_t *queued_control_events = NULL;
+
+/** True if the flush_queued_events_event is pending. */
+static int flush_queued_event_pending = 0;
+
+/** Lock to protect the above fields. */
+static tor_mutex_t *queued_control_events_lock = NULL;
+
+/** An event that should fire in order to flush the contents of
+ * queued_control_events. */
+static mainloop_event_t *flush_queued_events_event = NULL;
+
+void
+control_initialize_event_queue(void)
+{
+  if (queued_control_events == NULL) {
+    queued_control_events = smartlist_new();
+  }
+
+  if (flush_queued_events_event == NULL) {
+    struct event_base *b = tor_libevent_get_base();
+    if (b) {
+      flush_queued_events_event =
+        mainloop_event_new(flush_queued_events_cb, NULL);
+      tor_assert(flush_queued_events_event);
+    }
+  }
+
+  if (queued_control_events_lock == NULL) {
+    queued_control_events_lock = tor_mutex_new();
+    tor_threadlocal_init(&block_event_queue_flag);
+  }
+}
+
+static int *
+get_block_event_queue(void)
+{
+  int *val = tor_threadlocal_get(&block_event_queue_flag);
+  if (PREDICT_UNLIKELY(val == NULL)) {
+    val = tor_malloc_zero(sizeof(int));
+    tor_threadlocal_set(&block_event_queue_flag, val);
+  }
+  return val;
+}
+
+/** Helper: inserts an event on the list of events queued to be sent to
+ * one or more controllers, and schedules the events to be flushed if needed.
+ *
+ * This function takes ownership of <b>msg</b>, and may free it.
+ *
+ * We queue these events rather than send them immediately in order to break
+ * the dependency in our callgraph from code that generates events for the
+ * controller, and the network layer at large.  Otherwise, nearly every
+ * interesting part of Tor would potentially call every other interesting part
+ * of Tor.
+ */
+MOCK_IMPL(STATIC void,
+queue_control_event_string,(uint16_t event, char *msg))
+{
+  /* This is redundant with checks done elsewhere, but it's a last-ditch
+   * attempt to avoid queueing something we shouldn't have to queue. */
+  if (PREDICT_UNLIKELY( ! EVENT_IS_INTERESTING(event) )) {
+    tor_free(msg);
+    return;
+  }
+
+  int *block_event_queue = get_block_event_queue();
+  if (*block_event_queue) {
+    tor_free(msg);
+    return;
+  }
+
+  queued_event_t *ev = tor_malloc(sizeof(*ev));
+  ev->event = event;
+  ev->msg = msg;
+
+  /* No queueing an event while queueing an event */
+  ++*block_event_queue;
+
+  tor_mutex_acquire(queued_control_events_lock);
+  tor_assert(queued_control_events);
+  smartlist_add(queued_control_events, ev);
+
+  int activate_event = 0;
+  if (! flush_queued_event_pending && in_main_thread()) {
+    activate_event = 1;
+    flush_queued_event_pending = 1;
+  }
+
+  tor_mutex_release(queued_control_events_lock);
+
+  --*block_event_queue;
+
+  /* We just put an event on the queue; mark the queue to be
+   * flushed.  We only do this from the main thread for now; otherwise,
+   * we'd need to incur locking overhead in Libevent or use a socket.
+   */
+  if (activate_event) {
+    tor_assert(flush_queued_events_event);
+    mainloop_event_activate(flush_queued_events_event);
+  }
+}
+
+#define queued_event_free(ev) \
+  FREE_AND_NULL(queued_event_t, queued_event_free_, (ev))
+
+/** Release all storage held by <b>ev</b>. */
+static void
+queued_event_free_(queued_event_t *ev)
+{
+  if (ev == NULL)
+    return;
+
+  tor_free(ev->msg);
+  tor_free(ev);
+}
+
+/** Send every queued event to every controller that's interested in it,
+ * and remove the events from the queue.  If <b>force</b> is true,
+ * then make all controllers send their data out immediately, since we
+ * may be about to shut down. */
+static void
+queued_events_flush_all(int force)
+{
+  /* Make sure that we get all the pending log events, if there are any. */
+  flush_pending_log_callbacks();
+
+  if (PREDICT_UNLIKELY(queued_control_events == NULL)) {
+    return;
+  }
+  smartlist_t *all_conns = get_connection_array();
+  smartlist_t *controllers = smartlist_new();
+  smartlist_t *queued_events;
+
+  int *block_event_queue = get_block_event_queue();
+  ++*block_event_queue;
+
+  tor_mutex_acquire(queued_control_events_lock);
+  /* No queueing an event while flushing events. */
+  flush_queued_event_pending = 0;
+  queued_events = queued_control_events;
+  queued_control_events = smartlist_new();
+  tor_mutex_release(queued_control_events_lock);
+
+  /* Gather all the controllers that will care... */
+  SMARTLIST_FOREACH_BEGIN(all_conns, connection_t *, conn) {
+    if (conn->type == CONN_TYPE_CONTROL &&
+        !conn->marked_for_close &&
+        conn->state == CONTROL_CONN_STATE_OPEN) {
+      control_connection_t *control_conn = TO_CONTROL_CONN(conn);
+
+      smartlist_add(controllers, control_conn);
+    }
+  } SMARTLIST_FOREACH_END(conn);
+
+  SMARTLIST_FOREACH_BEGIN(queued_events, queued_event_t *, ev) {
+    const event_mask_t bit = ((event_mask_t)1) << ev->event;
+    const size_t msg_len = strlen(ev->msg);
+    SMARTLIST_FOREACH_BEGIN(controllers, control_connection_t *,
+                            control_conn) {
+      if (control_conn->event_mask & bit) {
+        connection_buf_add(ev->msg, msg_len, TO_CONN(control_conn));
+      }
+    } SMARTLIST_FOREACH_END(control_conn);
+
+    queued_event_free(ev);
+  } SMARTLIST_FOREACH_END(ev);
+
+  if (force) {
+    SMARTLIST_FOREACH_BEGIN(controllers, control_connection_t *,
+                            control_conn) {
+      connection_flush(TO_CONN(control_conn));
+    } SMARTLIST_FOREACH_END(control_conn);
+  }
+
+  smartlist_free(queued_events);
+  smartlist_free(controllers);
+
+  --*block_event_queue;
+}
+
+/** Libevent callback: Flushes pending events to controllers that are
+ * interested in them. */
+static void
+flush_queued_events_cb(mainloop_event_t *event, void *arg)
+{
+  (void) event;
+  (void) arg;
+  queued_events_flush_all(0);
+}
+
+/** Send an event to all v1 controllers that are listening for code
+ * <b>event</b>.  The event's body is given by <b>msg</b>.
+ *
+ * The EXTENDED_FORMAT and NONEXTENDED_FORMAT flags behave similarly with
+ * respect to the EXTENDED_EVENTS feature. */
+MOCK_IMPL(STATIC void,
+send_control_event_string,(uint16_t event,
+                           const char *msg))
+{
+  tor_assert(event >= EVENT_MIN_ && event <= EVENT_MAX_);
+  queue_control_event_string(event, tor_strdup(msg));
+}
+
+/** Helper for send_control_event and control_event_status:
+ * Send an event to all v1 controllers that are listening for code
+ * <b>event</b>.  The event's body is created by the printf-style format in
+ * <b>format</b>, and other arguments as provided. */
+static void
+send_control_event_impl(uint16_t event,
+                        const char *format, va_list ap)
+{
+  char *buf = NULL;
+  int len;
+
+  len = tor_vasprintf(&buf, format, ap);
+  if (len < 0) {
+    log_warn(LD_BUG, "Unable to format event for controller.");
+    return;
+  }
+
+  queue_control_event_string(event, buf);
+}
+
+/** Send an event to all v1 controllers that are listening for code
+ * <b>event</b>.  The event's body is created by the printf-style format in
+ * <b>format</b>, and other arguments as provided. */
+static void
+send_control_event(uint16_t event,
+                   const char *format, ...)
+{
+  va_list ap;
+  va_start(ap, format);
+  send_control_event_impl(event, format, ap);
+  va_end(ap);
+}
+
+/** Something major has happened to circuit <b>circ</b>: tell any
+ * interested control connections. */
+int
+control_event_circuit_status(origin_circuit_t *circ, circuit_status_event_t tp,
+                             int reason_code)
+{
+  const char *status;
+  char reasons[64] = "";
+
+  if (!EVENT_IS_INTERESTING(EVENT_CIRCUIT_STATUS))
+    return 0;
+  tor_assert(circ);
+
+  switch (tp)
+    {
+    case CIRC_EVENT_LAUNCHED: status = "LAUNCHED"; break;
+    case CIRC_EVENT_BUILT: status = "BUILT"; break;
+    case CIRC_EVENT_EXTENDED: status = "EXTENDED"; break;
+    case CIRC_EVENT_FAILED: status = "FAILED"; break;
+    case CIRC_EVENT_CLOSED: status = "CLOSED"; break;
+    default:
+      log_warn(LD_BUG, "Unrecognized status code %d", (int)tp);
+      tor_fragile_assert();
+      return 0;
+    }
+
+  if (tp == CIRC_EVENT_FAILED || tp == CIRC_EVENT_CLOSED) {
+    const char *reason_str = circuit_end_reason_to_control_string(reason_code);
+    char unk_reason_buf[16];
+    if (!reason_str) {
+      tor_snprintf(unk_reason_buf, 16, "UNKNOWN_%d", reason_code);
+      reason_str = unk_reason_buf;
+    }
+    if (reason_code > 0 && reason_code & END_CIRC_REASON_FLAG_REMOTE) {
+      tor_snprintf(reasons, sizeof(reasons),
+                   " REASON=DESTROYED REMOTE_REASON=%s", reason_str);
+    } else {
+      tor_snprintf(reasons, sizeof(reasons),
+                   " REASON=%s", reason_str);
+    }
+  }
+
+  {
+    char *circdesc = circuit_describe_status_for_controller(circ);
+    const char *sp = strlen(circdesc) ? " " : "";
+    send_control_event(EVENT_CIRCUIT_STATUS,
+                                "650 CIRC %lu %s%s%s%s\r\n",
+                                (unsigned long)circ->global_identifier,
+                                status, sp,
+                                circdesc,
+                                reasons);
+    tor_free(circdesc);
+  }
+
+  return 0;
+}
+
+/** Something minor has happened to circuit <b>circ</b>: tell any
+ * interested control connections. */
+static int
+control_event_circuit_status_minor(origin_circuit_t *circ,
+                                   circuit_status_minor_event_t e,
+                                   int purpose, const struct timeval *tv)
+{
+  const char *event_desc;
+  char event_tail[160] = "";
+  if (!EVENT_IS_INTERESTING(EVENT_CIRCUIT_STATUS_MINOR))
+    return 0;
+  tor_assert(circ);
+
+  switch (e)
+    {
+    case CIRC_MINOR_EVENT_PURPOSE_CHANGED:
+      event_desc = "PURPOSE_CHANGED";
+
+      {
+        /* event_tail can currently be up to 68 chars long */
+        const char *hs_state_str =
+          circuit_purpose_to_controller_hs_state_string(purpose);
+        tor_snprintf(event_tail, sizeof(event_tail),
+                     " OLD_PURPOSE=%s%s%s",
+                     circuit_purpose_to_controller_string(purpose),
+                     (hs_state_str != NULL) ? " OLD_HS_STATE=" : "",
+                     (hs_state_str != NULL) ? hs_state_str : "");
+      }
+
+      break;
+    case CIRC_MINOR_EVENT_CANNIBALIZED:
+      event_desc = "CANNIBALIZED";
+
+      {
+        /* event_tail can currently be up to 130 chars long */
+        const char *hs_state_str =
+          circuit_purpose_to_controller_hs_state_string(purpose);
+        const struct timeval *old_timestamp_began = tv;
+        char tbuf[ISO_TIME_USEC_LEN+1];
+        format_iso_time_nospace_usec(tbuf, old_timestamp_began);
+
+        tor_snprintf(event_tail, sizeof(event_tail),
+                     " OLD_PURPOSE=%s%s%s OLD_TIME_CREATED=%s",
+                     circuit_purpose_to_controller_string(purpose),
+                     (hs_state_str != NULL) ? " OLD_HS_STATE=" : "",
+                     (hs_state_str != NULL) ? hs_state_str : "",
+                     tbuf);
+      }
+
+      break;
+    default:
+      log_warn(LD_BUG, "Unrecognized status code %d", (int)e);
+      tor_fragile_assert();
+      return 0;
+    }
+
+  {
+    char *circdesc = circuit_describe_status_for_controller(circ);
+    const char *sp = strlen(circdesc) ? " " : "";
+    send_control_event(EVENT_CIRCUIT_STATUS_MINOR,
+                       "650 CIRC_MINOR %lu %s%s%s%s\r\n",
+                       (unsigned long)circ->global_identifier,
+                       event_desc, sp,
+                       circdesc,
+                       event_tail);
+    tor_free(circdesc);
+  }
+
+  return 0;
+}
+
+/**
+ * <b>circ</b> has changed its purpose from <b>old_purpose</b>: tell any
+ * interested controllers.
+ */
+int
+control_event_circuit_purpose_changed(origin_circuit_t *circ,
+                                      int old_purpose)
+{
+  return control_event_circuit_status_minor(circ,
+                                            CIRC_MINOR_EVENT_PURPOSE_CHANGED,
+                                            old_purpose,
+                                            NULL);
+}
+
+/**
+ * <b>circ</b> has changed its purpose from <b>old_purpose</b>, and its
+ * created-time from <b>old_tv_created</b>: tell any interested controllers.
+ */
+int
+control_event_circuit_cannibalized(origin_circuit_t *circ,
+                                   int old_purpose,
+                                   const struct timeval *old_tv_created)
+{
+  return control_event_circuit_status_minor(circ,
+                                            CIRC_MINOR_EVENT_CANNIBALIZED,
+                                            old_purpose,
+                                            old_tv_created);
+}
+
+/** Something has happened to the stream associated with AP connection
+ * <b>conn</b>: tell any interested control connections. */
+int
+control_event_stream_status(entry_connection_t *conn, stream_status_event_t tp,
+                            int reason_code)
+{
+  char reason_buf[64];
+  char addrport_buf[64];
+  const char *status;
+  circuit_t *circ;
+  origin_circuit_t *origin_circ = NULL;
+  char buf[256];
+  const char *purpose = "";
+  tor_assert(conn->socks_request);
+
+  if (!EVENT_IS_INTERESTING(EVENT_STREAM_STATUS))
+    return 0;
+
+  if (tp == STREAM_EVENT_CLOSED &&
+      (reason_code & END_STREAM_REASON_FLAG_ALREADY_SENT_CLOSED))
+    return 0;
+
+  write_stream_target_to_buf(conn, buf, sizeof(buf));
+
+  reason_buf[0] = '\0';
+  switch (tp)
+    {
+    case STREAM_EVENT_SENT_CONNECT: status = "SENTCONNECT"; break;
+    case STREAM_EVENT_SENT_RESOLVE: status = "SENTRESOLVE"; break;
+    case STREAM_EVENT_SUCCEEDED: status = "SUCCEEDED"; break;
+    case STREAM_EVENT_FAILED: status = "FAILED"; break;
+    case STREAM_EVENT_CLOSED: status = "CLOSED"; break;
+    case STREAM_EVENT_NEW: status = "NEW"; break;
+    case STREAM_EVENT_NEW_RESOLVE: status = "NEWRESOLVE"; break;
+    case STREAM_EVENT_FAILED_RETRIABLE: status = "DETACHED"; break;
+    case STREAM_EVENT_REMAP: status = "REMAP"; break;
+    default:
+      log_warn(LD_BUG, "Unrecognized status code %d", (int)tp);
+      return 0;
+    }
+  if (reason_code && (tp == STREAM_EVENT_FAILED ||
+                      tp == STREAM_EVENT_CLOSED ||
+                      tp == STREAM_EVENT_FAILED_RETRIABLE)) {
+    const char *reason_str = stream_end_reason_to_control_string(reason_code);
+    char *r = NULL;
+    if (!reason_str) {
+      tor_asprintf(&r, " UNKNOWN_%d", reason_code);
+      reason_str = r;
+    }
+    if (reason_code & END_STREAM_REASON_FLAG_REMOTE)
+      tor_snprintf(reason_buf, sizeof(reason_buf),
+                   " REASON=END REMOTE_REASON=%s", reason_str);
+    else
+      tor_snprintf(reason_buf, sizeof(reason_buf),
+                   " REASON=%s", reason_str);
+    tor_free(r);
+  } else if (reason_code && tp == STREAM_EVENT_REMAP) {
+    switch (reason_code) {
+    case REMAP_STREAM_SOURCE_CACHE:
+      strlcpy(reason_buf, " SOURCE=CACHE", sizeof(reason_buf));
+      break;
+    case REMAP_STREAM_SOURCE_EXIT:
+      strlcpy(reason_buf, " SOURCE=EXIT", sizeof(reason_buf));
+      break;
+    default:
+      tor_snprintf(reason_buf, sizeof(reason_buf), " REASON=UNKNOWN_%d",
+                   reason_code);
+      /* XXX do we want SOURCE=UNKNOWN_%d above instead? -RD */
+      break;
+    }
+  }
+
+  if (tp == STREAM_EVENT_NEW || tp == STREAM_EVENT_NEW_RESOLVE) {
+    /*
+     * When the control conn is an AF_UNIX socket and we have no address,
+     * it gets set to "(Tor_internal)"; see dnsserv_launch_request() in
+     * dnsserv.c.
+     */
+    if (strcmp(ENTRY_TO_CONN(conn)->address, "(Tor_internal)") != 0) {
+      tor_snprintf(addrport_buf,sizeof(addrport_buf), " SOURCE_ADDR=%s:%d",
+                   ENTRY_TO_CONN(conn)->address, ENTRY_TO_CONN(conn)->port);
+    } else {
+      /*
+       * else leave it blank so control on AF_UNIX doesn't need to make
+       * something up.
+       */
+      addrport_buf[0] = '\0';
+    }
+  } else {
+    addrport_buf[0] = '\0';
+  }
+
+  if (tp == STREAM_EVENT_NEW_RESOLVE) {
+    purpose = " PURPOSE=DNS_REQUEST";
+  } else if (tp == STREAM_EVENT_NEW) {
+    if (conn->use_begindir) {
+      connection_t *linked = ENTRY_TO_CONN(conn)->linked_conn;
+      int linked_dir_purpose = -1;
+      if (linked && linked->type == CONN_TYPE_DIR)
+        linked_dir_purpose = linked->purpose;
+      if (DIR_PURPOSE_IS_UPLOAD(linked_dir_purpose))
+        purpose = " PURPOSE=DIR_UPLOAD";
+      else
+        purpose = " PURPOSE=DIR_FETCH";
+    } else
+      purpose = " PURPOSE=USER";
+  }
+
+  circ = circuit_get_by_edge_conn(ENTRY_TO_EDGE_CONN(conn));
+  if (circ && CIRCUIT_IS_ORIGIN(circ))
+    origin_circ = TO_ORIGIN_CIRCUIT(circ);
+  send_control_event(EVENT_STREAM_STATUS,
+                        "650 STREAM %"PRIu64" %s %lu %s%s%s%s\r\n",
+                     (ENTRY_TO_CONN(conn)->global_identifier),
+                     status,
+                        origin_circ?
+                           (unsigned long)origin_circ->global_identifier : 0ul,
+                        buf, reason_buf, addrport_buf, purpose);
+
+  /* XXX need to specify its intended exit, etc? */
+
+  return 0;
+}
+
+/** Called when the status of an OR connection <b>conn</b> changes: tell any
+ * interested control connections. <b>tp</b> is the new status for the
+ * connection.  If <b>conn</b> has just closed or failed, then <b>reason</b>
+ * may be the reason why.
+ */
+int
+control_event_or_conn_status(or_connection_t *conn, or_conn_status_event_t tp,
+                             int reason)
+{
+  int ncircs = 0;
+  const char *status;
+  char name[128];
+  char ncircs_buf[32] = {0}; /* > 8 + log10(2^32)=10 + 2 */
+
+  if (!EVENT_IS_INTERESTING(EVENT_OR_CONN_STATUS))
+    return 0;
+
+  switch (tp)
+    {
+    case OR_CONN_EVENT_LAUNCHED: status = "LAUNCHED"; break;
+    case OR_CONN_EVENT_CONNECTED: status = "CONNECTED"; break;
+    case OR_CONN_EVENT_FAILED: status = "FAILED"; break;
+    case OR_CONN_EVENT_CLOSED: status = "CLOSED"; break;
+    case OR_CONN_EVENT_NEW: status = "NEW"; break;
+    default:
+      log_warn(LD_BUG, "Unrecognized status code %d", (int)tp);
+      return 0;
+    }
+  if (conn->chan) {
+    ncircs = circuit_count_pending_on_channel(TLS_CHAN_TO_BASE(conn->chan));
+  } else {
+    ncircs = 0;
+  }
+  ncircs += connection_or_get_num_circuits(conn);
+  if (ncircs && (tp == OR_CONN_EVENT_FAILED || tp == OR_CONN_EVENT_CLOSED)) {
+    tor_snprintf(ncircs_buf, sizeof(ncircs_buf), " NCIRCS=%d", ncircs);
+  }
+
+  orconn_target_get_name(name, sizeof(name), conn);
+  send_control_event(EVENT_OR_CONN_STATUS,
+                              "650 ORCONN %s %s%s%s%s ID=%"PRIu64"\r\n",
+                              name, status,
+                              reason ? " REASON=" : "",
+                              orconn_end_reason_to_control_string(reason),
+                              ncircs_buf,
+                              (conn->base_.global_identifier));
+
+  return 0;
+}
+
+/**
+ * Print out STREAM_BW event for a single conn
+ */
+int
+control_event_stream_bandwidth(edge_connection_t *edge_conn)
+{
+  struct timeval now;
+  char tbuf[ISO_TIME_USEC_LEN+1];
+  if (EVENT_IS_INTERESTING(EVENT_STREAM_BANDWIDTH_USED)) {
+    if (!edge_conn->n_read && !edge_conn->n_written)
+      return 0;
+
+    tor_gettimeofday(&now);
+    format_iso_time_nospace_usec(tbuf, &now);
+    send_control_event(EVENT_STREAM_BANDWIDTH_USED,
+                       "650 STREAM_BW %"PRIu64" %lu %lu %s\r\n",
+                       (edge_conn->base_.global_identifier),
+                       (unsigned long)edge_conn->n_read,
+                       (unsigned long)edge_conn->n_written,
+                       tbuf);
+
+    edge_conn->n_written = edge_conn->n_read = 0;
+  }
+
+  return 0;
+}
+
+/** A second or more has elapsed: tell any interested control
+ * connections how much bandwidth streams have used. */
+int
+control_event_stream_bandwidth_used(void)
+{
+  if (EVENT_IS_INTERESTING(EVENT_STREAM_BANDWIDTH_USED)) {
+    smartlist_t *conns = get_connection_array();
+    edge_connection_t *edge_conn;
+    struct timeval now;
+    char tbuf[ISO_TIME_USEC_LEN+1];
+
+    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn)
+    {
+        if (conn->type != CONN_TYPE_AP)
+          continue;
+        edge_conn = TO_EDGE_CONN(conn);
+        if (!edge_conn->n_read && !edge_conn->n_written)
+          continue;
+
+        tor_gettimeofday(&now);
+        format_iso_time_nospace_usec(tbuf, &now);
+        send_control_event(EVENT_STREAM_BANDWIDTH_USED,
+                           "650 STREAM_BW %"PRIu64" %lu %lu %s\r\n",
+                           (edge_conn->base_.global_identifier),
+                           (unsigned long)edge_conn->n_read,
+                           (unsigned long)edge_conn->n_written,
+                           tbuf);
+
+        edge_conn->n_written = edge_conn->n_read = 0;
+    }
+    SMARTLIST_FOREACH_END(conn);
+  }
+
+  return 0;
+}
+
+/** A second or more has elapsed: tell any interested control connections
+ * how much bandwidth origin circuits have used. */
+int
+control_event_circ_bandwidth_used(void)
+{
+  if (!EVENT_IS_INTERESTING(EVENT_CIRC_BANDWIDTH_USED))
+    return 0;
+
+  SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
+    if (!CIRCUIT_IS_ORIGIN(circ))
+      continue;
+
+    control_event_circ_bandwidth_used_for_circ(TO_ORIGIN_CIRCUIT(circ));
+  }
+  SMARTLIST_FOREACH_END(circ);
+
+  return 0;
+}
+
+/**
+ * Emit a CIRC_BW event line for a specific circuit.
+ *
+ * This function sets the values it emits to 0, and does not emit
+ * an event if there is no new data to report since the last call.
+ *
+ * Therefore, it may be called at any frequency.
+ */
+int
+control_event_circ_bandwidth_used_for_circ(origin_circuit_t *ocirc)
+{
+  struct timeval now;
+  char tbuf[ISO_TIME_USEC_LEN+1];
+
+  tor_assert(ocirc);
+
+  if (!EVENT_IS_INTERESTING(EVENT_CIRC_BANDWIDTH_USED))
+    return 0;
+
+  /* n_read_circ_bw and n_written_circ_bw are always updated
+   * when there is any new cell on a circuit, and set to 0 after
+   * the event, below.
+   *
+   * Therefore, checking them is sufficient to determine if there
+   * is new data to report. */
+  if (!ocirc->n_read_circ_bw && !ocirc->n_written_circ_bw)
+    return 0;
+
+  tor_gettimeofday(&now);
+  format_iso_time_nospace_usec(tbuf, &now);
+  send_control_event(EVENT_CIRC_BANDWIDTH_USED,
+                     "650 CIRC_BW ID=%d READ=%lu WRITTEN=%lu TIME=%s "
+                     "DELIVERED_READ=%lu OVERHEAD_READ=%lu "
+                     "DELIVERED_WRITTEN=%lu OVERHEAD_WRITTEN=%lu\r\n",
+                     ocirc->global_identifier,
+                     (unsigned long)ocirc->n_read_circ_bw,
+                     (unsigned long)ocirc->n_written_circ_bw,
+                     tbuf,
+                     (unsigned long)ocirc->n_delivered_read_circ_bw,
+                     (unsigned long)ocirc->n_overhead_read_circ_bw,
+                     (unsigned long)ocirc->n_delivered_written_circ_bw,
+                     (unsigned long)ocirc->n_overhead_written_circ_bw);
+  ocirc->n_written_circ_bw = ocirc->n_read_circ_bw = 0;
+  ocirc->n_overhead_written_circ_bw = ocirc->n_overhead_read_circ_bw = 0;
+  ocirc->n_delivered_written_circ_bw = ocirc->n_delivered_read_circ_bw = 0;
+
+  return 0;
+}
+
+/** Print out CONN_BW event for a single OR/DIR/EXIT <b>conn</b> and reset
+  * bandwidth counters. */
+int
+control_event_conn_bandwidth(connection_t *conn)
+{
+  const char *conn_type_str;
+  if (!get_options()->TestingEnableConnBwEvent ||
+      !EVENT_IS_INTERESTING(EVENT_CONN_BW))
+    return 0;
+  if (!conn->n_read_conn_bw && !conn->n_written_conn_bw)
+    return 0;
+  switch (conn->type) {
+    case CONN_TYPE_OR:
+      conn_type_str = "OR";
+      break;
+    case CONN_TYPE_DIR:
+      conn_type_str = "DIR";
+      break;
+    case CONN_TYPE_EXIT:
+      conn_type_str = "EXIT";
+      break;
+    default:
+      return 0;
+  }
+  send_control_event(EVENT_CONN_BW,
+                     "650 CONN_BW ID=%"PRIu64" TYPE=%s "
+                     "READ=%lu WRITTEN=%lu\r\n",
+                     (conn->global_identifier),
+                     conn_type_str,
+                     (unsigned long)conn->n_read_conn_bw,
+                     (unsigned long)conn->n_written_conn_bw);
+  conn->n_written_conn_bw = conn->n_read_conn_bw = 0;
+  return 0;
+}
+
+/** A second or more has elapsed: tell any interested control
+ * connections how much bandwidth connections have used. */
+int
+control_event_conn_bandwidth_used(void)
+{
+  if (get_options()->TestingEnableConnBwEvent &&
+      EVENT_IS_INTERESTING(EVENT_CONN_BW)) {
+    SMARTLIST_FOREACH(get_connection_array(), connection_t *, conn,
+                      control_event_conn_bandwidth(conn));
+  }
+  return 0;
+}
+
+/** Helper: iterate over cell statistics of <b>circ</b> and sum up added
+ * cells, removed cells, and waiting times by cell command and direction.
+ * Store results in <b>cell_stats</b>.  Free cell statistics of the
+ * circuit afterwards. */
+void
+sum_up_cell_stats_by_command(circuit_t *circ, cell_stats_t *cell_stats)
+{
+  memset(cell_stats, 0, sizeof(cell_stats_t));
+  SMARTLIST_FOREACH_BEGIN(circ->testing_cell_stats,
+                          const testing_cell_stats_entry_t *, ent) {
+    tor_assert(ent->command <= CELL_COMMAND_MAX_);
+    if (!ent->removed && !ent->exitward) {
+      cell_stats->added_cells_appward[ent->command] += 1;
+    } else if (!ent->removed && ent->exitward) {
+      cell_stats->added_cells_exitward[ent->command] += 1;
+    } else if (!ent->exitward) {
+      cell_stats->removed_cells_appward[ent->command] += 1;
+      cell_stats->total_time_appward[ent->command] += ent->waiting_time * 10;
+    } else {
+      cell_stats->removed_cells_exitward[ent->command] += 1;
+      cell_stats->total_time_exitward[ent->command] += ent->waiting_time * 10;
+    }
+  } SMARTLIST_FOREACH_END(ent);
+  circuit_clear_testing_cell_stats(circ);
+}
+
+/** Helper: append a cell statistics string to <code>event_parts</code>,
+ * prefixed with <code>key</code>=.  Statistics consist of comma-separated
+ * key:value pairs with lower-case command strings as keys and cell
+ * numbers or total waiting times as values.  A key:value pair is included
+ * if the entry in <code>include_if_non_zero</code> is not zero, but with
+ * the (possibly zero) entry from <code>number_to_include</code>.  Both
+ * arrays are expected to have a length of CELL_COMMAND_MAX_ + 1.  If no
+ * entry in <code>include_if_non_zero</code> is positive, no string will
+ * be added to <code>event_parts</code>. */
+void
+append_cell_stats_by_command(smartlist_t *event_parts, const char *key,
+                             const uint64_t *include_if_non_zero,
+                             const uint64_t *number_to_include)
+{
+  smartlist_t *key_value_strings = smartlist_new();
+  int i;
+  for (i = 0; i <= CELL_COMMAND_MAX_; i++) {
+    if (include_if_non_zero[i] > 0) {
+      smartlist_add_asprintf(key_value_strings, "%s:%"PRIu64,
+                             cell_command_to_string(i),
+                             (number_to_include[i]));
+    }
+  }
+  if (smartlist_len(key_value_strings) > 0) {
+    char *joined = smartlist_join_strings(key_value_strings, ",", 0, NULL);
+    smartlist_add_asprintf(event_parts, "%s=%s", key, joined);
+    SMARTLIST_FOREACH(key_value_strings, char *, cp, tor_free(cp));
+    tor_free(joined);
+  }
+  smartlist_free(key_value_strings);
+}
+
+/** Helper: format <b>cell_stats</b> for <b>circ</b> for inclusion in a
+ * CELL_STATS event and write result string to <b>event_string</b>. */
+void
+format_cell_stats(char **event_string, circuit_t *circ,
+                  cell_stats_t *cell_stats)
+{
+  smartlist_t *event_parts = smartlist_new();
+  if (CIRCUIT_IS_ORIGIN(circ)) {
+    origin_circuit_t *ocirc = TO_ORIGIN_CIRCUIT(circ);
+    smartlist_add_asprintf(event_parts, "ID=%lu",
+                 (unsigned long)ocirc->global_identifier);
+  } else if (TO_OR_CIRCUIT(circ)->p_chan) {
+    or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
+    smartlist_add_asprintf(event_parts, "InboundQueue=%lu",
+                 (unsigned long)or_circ->p_circ_id);
+    smartlist_add_asprintf(event_parts, "InboundConn=%"PRIu64,
+                 (or_circ->p_chan->global_identifier));
+    append_cell_stats_by_command(event_parts, "InboundAdded",
+                                 cell_stats->added_cells_appward,
+                                 cell_stats->added_cells_appward);
+    append_cell_stats_by_command(event_parts, "InboundRemoved",
+                                 cell_stats->removed_cells_appward,
+                                 cell_stats->removed_cells_appward);
+    append_cell_stats_by_command(event_parts, "InboundTime",
+                                 cell_stats->removed_cells_appward,
+                                 cell_stats->total_time_appward);
+  }
+  if (circ->n_chan) {
+    smartlist_add_asprintf(event_parts, "OutboundQueue=%lu",
+                     (unsigned long)circ->n_circ_id);
+    smartlist_add_asprintf(event_parts, "OutboundConn=%"PRIu64,
+                 (circ->n_chan->global_identifier));
+    append_cell_stats_by_command(event_parts, "OutboundAdded",
+                                 cell_stats->added_cells_exitward,
+                                 cell_stats->added_cells_exitward);
+    append_cell_stats_by_command(event_parts, "OutboundRemoved",
+                                 cell_stats->removed_cells_exitward,
+                                 cell_stats->removed_cells_exitward);
+    append_cell_stats_by_command(event_parts, "OutboundTime",
+                                 cell_stats->removed_cells_exitward,
+                                 cell_stats->total_time_exitward);
+  }
+  *event_string = smartlist_join_strings(event_parts, " ", 0, NULL);
+  SMARTLIST_FOREACH(event_parts, char *, cp, tor_free(cp));
+  smartlist_free(event_parts);
+}
+
+/** A second or more has elapsed: tell any interested control connection
+ * how many cells have been processed for a given circuit. */
+int
+control_event_circuit_cell_stats(void)
+{
+  cell_stats_t *cell_stats;
+  char *event_string;
+  if (!get_options()->TestingEnableCellStatsEvent ||
+      !EVENT_IS_INTERESTING(EVENT_CELL_STATS))
+    return 0;
+  cell_stats = tor_malloc(sizeof(cell_stats_t));
+  SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
+    if (!circ->testing_cell_stats)
+      continue;
+    sum_up_cell_stats_by_command(circ, cell_stats);
+    format_cell_stats(&event_string, circ, cell_stats);
+    send_control_event(EVENT_CELL_STATS,
+                       "650 CELL_STATS %s\r\n", event_string);
+    tor_free(event_string);
+  }
+  SMARTLIST_FOREACH_END(circ);
+  tor_free(cell_stats);
+  return 0;
+}
+
+/* about 5 minutes worth. */
+#define N_BW_EVENTS_TO_CACHE 300
+/* Index into cached_bw_events to next write. */
+static int next_measurement_idx = 0;
+/* number of entries set in n_measurements */
+static int n_measurements = 0;
+static struct cached_bw_event_s {
+  uint32_t n_read;
+  uint32_t n_written;
+} cached_bw_events[N_BW_EVENTS_TO_CACHE];
+
+/** A second or more has elapsed: tell any interested control
+ * connections how much bandwidth we used. */
+int
+control_event_bandwidth_used(uint32_t n_read, uint32_t n_written)
+{
+  cached_bw_events[next_measurement_idx].n_read = n_read;
+  cached_bw_events[next_measurement_idx].n_written = n_written;
+  if (++next_measurement_idx == N_BW_EVENTS_TO_CACHE)
+    next_measurement_idx = 0;
+  if (n_measurements < N_BW_EVENTS_TO_CACHE)
+    ++n_measurements;
+
+  if (EVENT_IS_INTERESTING(EVENT_BANDWIDTH_USED)) {
+    send_control_event(EVENT_BANDWIDTH_USED,
+                       "650 BW %lu %lu\r\n",
+                       (unsigned long)n_read,
+                       (unsigned long)n_written);
+  }
+
+  return 0;
+}
+
+char *
+get_bw_samples(void)
+{
+  int i;
+  int idx = (next_measurement_idx + N_BW_EVENTS_TO_CACHE - n_measurements)
+    % N_BW_EVENTS_TO_CACHE;
+  tor_assert(0 <= idx && idx < N_BW_EVENTS_TO_CACHE);
+
+  smartlist_t *elements = smartlist_new();
+
+  for (i = 0; i < n_measurements; ++i) {
+    tor_assert(0 <= idx && idx < N_BW_EVENTS_TO_CACHE);
+    const struct cached_bw_event_s *bwe = &cached_bw_events[idx];
+
+    smartlist_add_asprintf(elements, "%u,%u",
+                           (unsigned)bwe->n_read,
+                           (unsigned)bwe->n_written);
+
+    idx = (idx + 1) % N_BW_EVENTS_TO_CACHE;
+  }
+
+  char *result = smartlist_join_strings(elements, " ", 0, NULL);
+
+  SMARTLIST_FOREACH(elements, char *, cp, tor_free(cp));
+  smartlist_free(elements);
+
+  return result;
+}
+
+/** Called when we are sending a log message to the controllers: suspend
+ * sending further log messages to the controllers until we're done.  Used by
+ * CONN_LOG_PROTECT. */
+void
+disable_control_logging(void)
+{
+  ++disable_log_messages;
+}
+
+/** We're done sending a log message to the controllers: re-enable controller
+ * logging.  Used by CONN_LOG_PROTECT. */
+void
+enable_control_logging(void)
+{
+  if (--disable_log_messages < 0)
+    tor_assert(0);
+}
+
+/** We got a log message: tell any interested control connections. */
+void
+control_event_logmsg(int severity, log_domain_mask_t domain, const char *msg)
+{
+  int event;
+
+  /* Don't even think of trying to add stuff to a buffer from a cpuworker
+   * thread. (See #25987 for plan to fix.) */
+  if (! in_main_thread())
+    return;
+
+  if (disable_log_messages)
+    return;
+
+  if (domain == LD_BUG && EVENT_IS_INTERESTING(EVENT_STATUS_GENERAL) &&
+      severity <= LOG_NOTICE) {
+    char *esc = esc_for_log(msg);
+    ++disable_log_messages;
+    control_event_general_status(severity, "BUG REASON=%s", esc);
+    --disable_log_messages;
+    tor_free(esc);
+  }
+
+  event = log_severity_to_event(severity);
+  if (event >= 0 && EVENT_IS_INTERESTING(event)) {
+    char *b = NULL;
+    const char *s;
+    if (strchr(msg, '\n')) {
+      char *cp;
+      b = tor_strdup(msg);
+      for (cp = b; *cp; ++cp)
+        if (*cp == '\r' || *cp == '\n')
+          *cp = ' ';
+    }
+    switch (severity) {
+      case LOG_DEBUG: s = "DEBUG"; break;
+      case LOG_INFO: s = "INFO"; break;
+      case LOG_NOTICE: s = "NOTICE"; break;
+      case LOG_WARN: s = "WARN"; break;
+      case LOG_ERR: s = "ERR"; break;
+      default: s = "UnknownLogSeverity"; break;
+    }
+    ++disable_log_messages;
+    send_control_event(event,  "650 %s %s\r\n", s, b?b:msg);
+    if (severity == LOG_ERR) {
+      /* Force a flush, since we may be about to die horribly */
+      queued_events_flush_all(1);
+    }
+    --disable_log_messages;
+    tor_free(b);
+  }
+}
+
+/**
+ * Logging callback: called when there is a queued pending log callback.
+ */
+void
+control_event_logmsg_pending(void)
+{
+  if (! in_main_thread()) {
+    /* We can't handle this case yet, since we're using a
+     * mainloop_event_t to invoke queued_events_flush_all.  We ought to
+     * use a different mechanism instead: see #25987.
+     **/
+    return;
+  }
+  tor_assert(flush_queued_events_event);
+  mainloop_event_activate(flush_queued_events_event);
+}
+
+/** Called whenever we receive new router descriptors: tell any
+ * interested control connections.  <b>routers</b> is a list of
+ * routerinfo_t's.
+ */
+int
+control_event_descriptors_changed(smartlist_t *routers)
+{
+  char *msg;
+
+  if (!EVENT_IS_INTERESTING(EVENT_NEW_DESC))
+    return 0;
+
+  {
+    smartlist_t *names = smartlist_new();
+    char *ids;
+    SMARTLIST_FOREACH(routers, routerinfo_t *, ri, {
+        char *b = tor_malloc(MAX_VERBOSE_NICKNAME_LEN+1);
+        router_get_verbose_nickname(b, ri);
+        smartlist_add(names, b);
+      });
+    ids = smartlist_join_strings(names, " ", 0, NULL);
+    tor_asprintf(&msg, "650 NEWDESC %s\r\n", ids);
+    send_control_event_string(EVENT_NEW_DESC,  msg);
+    tor_free(ids);
+    tor_free(msg);
+    SMARTLIST_FOREACH(names, char *, cp, tor_free(cp));
+    smartlist_free(names);
+  }
+  return 0;
+}
+
+/** Called when an address mapping on <b>from</b> from changes to <b>to</b>.
+ * <b>expires</b> values less than 3 are special; see connection_edge.c.  If
+ * <b>error</b> is non-NULL, it is an error code describing the failure
+ * mode of the mapping.
+ */
+int
+control_event_address_mapped(const char *from, const char *to, time_t expires,
+                             const char *error, const int cached)
+{
+  if (!EVENT_IS_INTERESTING(EVENT_ADDRMAP))
+    return 0;
+
+  if (expires < 3 || expires == TIME_MAX)
+    send_control_event(EVENT_ADDRMAP,
+                                "650 ADDRMAP %s %s NEVER %s%s"
+                                "CACHED=\"%s\"\r\n",
+                                  from, to, error?error:"", error?" ":"",
+                                cached?"YES":"NO");
+  else {
+    char buf[ISO_TIME_LEN+1];
+    char buf2[ISO_TIME_LEN+1];
+    format_local_iso_time(buf,expires);
+    format_iso_time(buf2,expires);
+    send_control_event(EVENT_ADDRMAP,
+                                "650 ADDRMAP %s %s \"%s\""
+                                " %s%sEXPIRES=\"%s\" CACHED=\"%s\"\r\n",
+                                from, to, buf,
+                                error?error:"", error?" ":"",
+                                buf2, cached?"YES":"NO");
+  }
+
+  return 0;
+}
+/** The network liveness has changed; this is called from circuitstats.c
+ * whenever we receive a cell, or when timeout expires and we assume the
+ * network is down. */
+int
+control_event_network_liveness_update(int liveness)
+{
+  if (liveness > 0) {
+    if (get_cached_network_liveness() <= 0) {
+      /* Update cached liveness */
+      set_cached_network_liveness(1);
+      log_debug(LD_CONTROL, "Sending NETWORK_LIVENESS UP");
+      send_control_event_string(EVENT_NETWORK_LIVENESS,
+                                "650 NETWORK_LIVENESS UP\r\n");
+    }
+    /* else was already live, no-op */
+  } else {
+    if (get_cached_network_liveness() > 0) {
+      /* Update cached liveness */
+      set_cached_network_liveness(0);
+      log_debug(LD_CONTROL, "Sending NETWORK_LIVENESS DOWN");
+      send_control_event_string(EVENT_NETWORK_LIVENESS,
+                                "650 NETWORK_LIVENESS DOWN\r\n");
+    }
+    /* else was already dead, no-op */
+  }
+
+  return 0;
+}
+
+/** Helper function for NS-style events. Constructs and sends an event
+ * of type <b>event</b> with string <b>event_string</b> out of the set of
+ * networkstatuses <b>statuses</b>. Currently it is used for NS events
+ * and NEWCONSENSUS events. */
+static int
+control_event_networkstatus_changed_helper(smartlist_t *statuses,
+                                           uint16_t event,
+                                           const char *event_string)
+{
+  smartlist_t *strs;
+  char *s, *esc = NULL;
+  if (!EVENT_IS_INTERESTING(event) || !smartlist_len(statuses))
+    return 0;
+
+  strs = smartlist_new();
+  smartlist_add_strdup(strs, "650+");
+  smartlist_add_strdup(strs, event_string);
+  smartlist_add_strdup(strs, "\r\n");
+  SMARTLIST_FOREACH(statuses, const routerstatus_t *, rs,
+    {
+      s = networkstatus_getinfo_helper_single(rs);
+      if (!s) continue;
+      smartlist_add(strs, s);
+    });
+
+  s = smartlist_join_strings(strs, "", 0, NULL);
+  write_escaped_data(s, strlen(s), &esc);
+  SMARTLIST_FOREACH(strs, char *, cp, tor_free(cp));
+  smartlist_free(strs);
+  tor_free(s);
+  send_control_event_string(event,  esc);
+  send_control_event_string(event,
+                            "650 OK\r\n");
+
+  tor_free(esc);
+  return 0;
+}
+
+/** Called when the routerstatus_ts <b>statuses</b> have changed: sends
+ * an NS event to any controller that cares. */
+int
+control_event_networkstatus_changed(smartlist_t *statuses)
+{
+  return control_event_networkstatus_changed_helper(statuses, EVENT_NS, "NS");
+}
+
+/** Called when we get a new consensus networkstatus. Sends a NEWCONSENSUS
+ * event consisting of an NS-style line for each relay in the consensus. */
+int
+control_event_newconsensus(const networkstatus_t *consensus)
+{
+  if (!control_event_is_interesting(EVENT_NEWCONSENSUS))
+    return 0;
+  return control_event_networkstatus_changed_helper(
+           consensus->routerstatus_list, EVENT_NEWCONSENSUS, "NEWCONSENSUS");
+}
+
+/** Called when we compute a new circuitbuildtimeout */
+int
+control_event_buildtimeout_set(buildtimeout_set_event_t type,
+                               const char *args)
+{
+  const char *type_string = NULL;
+
+  if (!control_event_is_interesting(EVENT_BUILDTIMEOUT_SET))
+    return 0;
+
+  switch (type) {
+    case BUILDTIMEOUT_SET_EVENT_COMPUTED:
+      type_string = "COMPUTED";
+      break;
+    case BUILDTIMEOUT_SET_EVENT_RESET:
+      type_string = "RESET";
+      break;
+    case BUILDTIMEOUT_SET_EVENT_SUSPENDED:
+      type_string = "SUSPENDED";
+      break;
+    case BUILDTIMEOUT_SET_EVENT_DISCARD:
+      type_string = "DISCARD";
+      break;
+    case BUILDTIMEOUT_SET_EVENT_RESUME:
+      type_string = "RESUME";
+      break;
+    default:
+      type_string = "UNKNOWN";
+      break;
+  }
+
+  send_control_event(EVENT_BUILDTIMEOUT_SET,
+                     "650 BUILDTIMEOUT_SET %s %s\r\n",
+                     type_string, args);
+
+  return 0;
+}
+
+/** Called when a signal has been processed from signal_callback */
+int
+control_event_signal(uintptr_t signal_num)
+{
+  const char *signal_string = NULL;
+
+  if (!control_event_is_interesting(EVENT_GOT_SIGNAL))
+    return 0;
+
+  switch (signal_num) {
+    case SIGHUP:
+      signal_string = "RELOAD";
+      break;
+    case SIGUSR1:
+      signal_string = "DUMP";
+      break;
+    case SIGUSR2:
+      signal_string = "DEBUG";
+      break;
+    case SIGNEWNYM:
+      signal_string = "NEWNYM";
+      break;
+    case SIGCLEARDNSCACHE:
+      signal_string = "CLEARDNSCACHE";
+      break;
+    case SIGHEARTBEAT:
+      signal_string = "HEARTBEAT";
+      break;
+    default:
+      log_warn(LD_BUG, "Unrecognized signal %lu in control_event_signal",
+               (unsigned long)signal_num);
+      return -1;
+  }
+
+  send_control_event(EVENT_GOT_SIGNAL,  "650 SIGNAL %s\r\n",
+                     signal_string);
+  return 0;
+}
+
+/** Called when a single local_routerstatus_t has changed: Sends an NS event
+ * to any controller that cares. */
+int
+control_event_networkstatus_changed_single(const routerstatus_t *rs)
+{
+  smartlist_t *statuses;
+  int r;
+
+  if (!EVENT_IS_INTERESTING(EVENT_NS))
+    return 0;
+
+  statuses = smartlist_new();
+  smartlist_add(statuses, (void*)rs);
+  r = control_event_networkstatus_changed(statuses);
+  smartlist_free(statuses);
+  return r;
+}
+
+/** Our own router descriptor has changed; tell any controllers that care.
+ */
+int
+control_event_my_descriptor_changed(void)
+{
+  send_control_event(EVENT_DESCCHANGED,  "650 DESCCHANGED\r\n");
+  return 0;
+}
+
+/** Helper: sends a status event where <b>type</b> is one of
+ * EVENT_STATUS_{GENERAL,CLIENT,SERVER}, where <b>severity</b> is one of
+ * LOG_{NOTICE,WARN,ERR}, and where <b>format</b> is a printf-style format
+ * string corresponding to <b>args</b>. */
+static int
+control_event_status(int type, int severity, const char *format, va_list args)
+{
+  char *user_buf = NULL;
+  char format_buf[160];
+  const char *status, *sev;
+
+  switch (type) {
+    case EVENT_STATUS_GENERAL:
+      status = "STATUS_GENERAL";
+      break;
+    case EVENT_STATUS_CLIENT:
+      status = "STATUS_CLIENT";
+      break;
+    case EVENT_STATUS_SERVER:
+      status = "STATUS_SERVER";
+      break;
+    default:
+      log_warn(LD_BUG, "Unrecognized status type %d", type);
+      return -1;
+  }
+  switch (severity) {
+    case LOG_NOTICE:
+      sev = "NOTICE";
+      break;
+    case LOG_WARN:
+      sev = "WARN";
+      break;
+    case LOG_ERR:
+      sev = "ERR";
+      break;
+    default:
+      log_warn(LD_BUG, "Unrecognized status severity %d", severity);
+      return -1;
+  }
+  if (tor_snprintf(format_buf, sizeof(format_buf), "650 %s %s",
+                   status, sev)<0) {
+    log_warn(LD_BUG, "Format string too long.");
+    return -1;
+  }
+  tor_vasprintf(&user_buf, format, args);
+
+  send_control_event(type,  "%s %s\r\n", format_buf, user_buf);
+  tor_free(user_buf);
+  return 0;
+}
+
+#define CONTROL_EVENT_STATUS_BODY(event, sev)                   \
+  int r;                                                        \
+  do {                                                          \
+    va_list ap;                                                 \
+    if (!EVENT_IS_INTERESTING(event))                           \
+      return 0;                                                 \
+                                                                \
+    va_start(ap, format);                                       \
+    r = control_event_status((event), (sev), format, ap);       \
+    va_end(ap);                                                 \
+  } while (0)
+
+/** Format and send an EVENT_STATUS_GENERAL event whose main text is obtained
+ * by formatting the arguments using the printf-style <b>format</b>. */
+int
+control_event_general_status(int severity, const char *format, ...)
+{
+  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_GENERAL, severity);
+  return r;
+}
+
+/** Format and send an EVENT_STATUS_GENERAL LOG_ERR event, and flush it to the
+ * controller(s) immediately. */
+int
+control_event_general_error(const char *format, ...)
+{
+  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_GENERAL, LOG_ERR);
+  /* Force a flush, since we may be about to die horribly */
+  queued_events_flush_all(1);
+  return r;
+}
+
+/** Format and send an EVENT_STATUS_CLIENT event whose main text is obtained
+ * by formatting the arguments using the printf-style <b>format</b>. */
+int
+control_event_client_status(int severity, const char *format, ...)
+{
+  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_CLIENT, severity);
+  return r;
+}
+
+/** Format and send an EVENT_STATUS_CLIENT LOG_ERR event, and flush it to the
+ * controller(s) immediately. */
+int
+control_event_client_error(const char *format, ...)
+{
+  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_CLIENT, LOG_ERR);
+  /* Force a flush, since we may be about to die horribly */
+  queued_events_flush_all(1);
+  return r;
+}
+
+/** Format and send an EVENT_STATUS_SERVER event whose main text is obtained
+ * by formatting the arguments using the printf-style <b>format</b>. */
+int
+control_event_server_status(int severity, const char *format, ...)
+{
+  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_SERVER, severity);
+  return r;
+}
+
+/** Format and send an EVENT_STATUS_SERVER LOG_ERR event, and flush it to the
+ * controller(s) immediately. */
+int
+control_event_server_error(const char *format, ...)
+{
+  CONTROL_EVENT_STATUS_BODY(EVENT_STATUS_SERVER, LOG_ERR);
+  /* Force a flush, since we may be about to die horribly */
+  queued_events_flush_all(1);
+  return r;
+}
+
+/** Called when the status of an entry guard with the given <b>nickname</b>
+ * and identity <b>digest</b> has changed to <b>status</b>: tells any
+ * controllers that care. */
+int
+control_event_guard(const char *nickname, const char *digest,
+                    const char *status)
+{
+  char hbuf[HEX_DIGEST_LEN+1];
+  base16_encode(hbuf, sizeof(hbuf), digest, DIGEST_LEN);
+  if (!EVENT_IS_INTERESTING(EVENT_GUARD))
+    return 0;
+
+  {
+    char buf[MAX_VERBOSE_NICKNAME_LEN+1];
+    const node_t *node = node_get_by_id(digest);
+    if (node) {
+      node_get_verbose_nickname(node, buf);
+    } else {
+      tor_snprintf(buf, sizeof(buf), "$%s~%s", hbuf, nickname);
+    }
+    send_control_event(EVENT_GUARD,
+                       "650 GUARD ENTRY %s %s\r\n", buf, status);
+  }
+  return 0;
+}
+
+/** Called when a configuration option changes. This is generally triggered
+ * by SETCONF requests and RELOAD/SIGHUP signals. The <b>elements</b> is
+ * a smartlist_t containing (key, value, ...) pairs in sequence.
+ * <b>value</b> can be NULL. */
+int
+control_event_conf_changed(const smartlist_t *elements)
+{
+  int i;
+  char *result;
+  smartlist_t *lines;
+  if (!EVENT_IS_INTERESTING(EVENT_CONF_CHANGED) ||
+      smartlist_len(elements) == 0) {
+    return 0;
+  }
+  lines = smartlist_new();
+  for (i = 0; i < smartlist_len(elements); i += 2) {
+    char *k = smartlist_get(elements, i);
+    char *v = smartlist_get(elements, i+1);
+    if (v == NULL) {
+      smartlist_add_asprintf(lines, "650-%s", k);
+    } else {
+      smartlist_add_asprintf(lines, "650-%s=%s", k, v);
+    }
+  }
+  result = smartlist_join_strings(lines, "\r\n", 0, NULL);
+  send_control_event(EVENT_CONF_CHANGED,
+    "650-CONF_CHANGED\r\n%s\r\n650 OK\r\n", result);
+  tor_free(result);
+  SMARTLIST_FOREACH(lines, char *, cp, tor_free(cp));
+  smartlist_free(lines);
+  return 0;
+}
+
+/** We just generated a new summary of which countries we've seen clients
+ * from recently. Send a copy to the controller in case it wants to
+ * display it for the user. */
+void
+control_event_clients_seen(const char *controller_str)
+{
+  send_control_event(EVENT_CLIENTS_SEEN,
+    "650 CLIENTS_SEEN %s\r\n", controller_str);
+}
+
+/** A new pluggable transport called <b>transport_name</b> was
+ *  launched on <b>addr</b>:<b>port</b>. <b>mode</b> is either
+ *  "server" or "client" depending on the mode of the pluggable
+ *  transport.
+ *  "650" SP "TRANSPORT_LAUNCHED" SP Mode SP Name SP Address SP Port
+ */
+void
+control_event_transport_launched(const char *mode, const char *transport_name,
+                                 tor_addr_t *addr, uint16_t port)
+{
+  send_control_event(EVENT_TRANSPORT_LAUNCHED,
+                     "650 TRANSPORT_LAUNCHED %s %s %s %u\r\n",
+                     mode, transport_name, fmt_addr(addr), port);
+}
+
+/** A pluggable transport called <b>pt_name</b> has emitted a log message
+ * found in <b>message</b> at <b>severity</b> log level. */
+void
+control_event_pt_log(const char *log)
+{
+  send_control_event(EVENT_PT_LOG,
+                     "650 PT_LOG %s\r\n",
+                     log);
+}
+
+/** A pluggable transport has emitted a STATUS message found in
+ * <b>status</b>. */
+void
+control_event_pt_status(const char *status)
+{
+  send_control_event(EVENT_PT_STATUS,
+                     "650 PT_STATUS %s\r\n",
+                     status);
+}
+
+/** Convert rendezvous auth type to string for HS_DESC control events
+ */
+const char *
+rend_auth_type_to_string(rend_auth_type_t auth_type)
+{
+  const char *str;
+
+  switch (auth_type) {
+    case REND_NO_AUTH:
+      str = "NO_AUTH";
+      break;
+    case REND_BASIC_AUTH:
+      str = "BASIC_AUTH";
+      break;
+    case REND_STEALTH_AUTH:
+      str = "STEALTH_AUTH";
+      break;
+    default:
+      str = "UNKNOWN";
+  }
+
+  return str;
+}
+
+/** Return either the onion address if the given pointer is a non empty
+ * string else the unknown string. */
+static const char *
+rend_hsaddress_str_or_unknown(const char *onion_address)
+{
+  static const char *str_unknown = "UNKNOWN";
+  const char *str_ret = str_unknown;
+
+  /* No valid pointer, unknown it is. */
+  if (!onion_address) {
+    goto end;
+  }
+  /* Empty onion address thus we don't know, unknown it is. */
+  if (onion_address[0] == '\0') {
+    goto end;
+  }
+  /* All checks are good so return the given onion address. */
+  str_ret = onion_address;
+
+ end:
+  return str_ret;
+}
+
+/** send HS_DESC requested event.
+ *
+ * <b>rend_query</b> is used to fetch requested onion address and auth type.
+ * <b>hs_dir</b> is the description of contacting hs directory.
+ * <b>desc_id_base32</b> is the ID of requested hs descriptor.
+ * <b>hsdir_index</b> is the HSDir fetch index value for v3, an hex string.
+ */
+void
+control_event_hs_descriptor_requested(const char *onion_address,
+                                      rend_auth_type_t auth_type,
+                                      const char *id_digest,
+                                      const char *desc_id,
+                                      const char *hsdir_index)
+{
+  char *hsdir_index_field = NULL;
+
+  if (BUG(!id_digest || !desc_id)) {
+    return;
+  }
+
+  if (hsdir_index) {
+    tor_asprintf(&hsdir_index_field, " HSDIR_INDEX=%s", hsdir_index);
+  }
+
+  send_control_event(EVENT_HS_DESC,
+                     "650 HS_DESC REQUESTED %s %s %s %s%s\r\n",
+                     rend_hsaddress_str_or_unknown(onion_address),
+                     rend_auth_type_to_string(auth_type),
+                     node_describe_longname_by_id(id_digest),
+                     desc_id,
+                     hsdir_index_field ? hsdir_index_field : "");
+  tor_free(hsdir_index_field);
+}
+
+/** send HS_DESC CREATED event when a local service generates a descriptor.
+ *
+ * <b>onion_address</b> is service address.
+ * <b>desc_id</b> is the descriptor ID.
+ * <b>replica</b> is the the descriptor replica number. If it is negative, it
+ * is ignored.
+ */
+void
+control_event_hs_descriptor_created(const char *onion_address,
+                                    const char *desc_id,
+                                    int replica)
+{
+  char *replica_field = NULL;
+
+  if (BUG(!onion_address || !desc_id)) {
+    return;
+  }
+
+  if (replica >= 0) {
+    tor_asprintf(&replica_field, " REPLICA=%d", replica);
+  }
+
+  send_control_event(EVENT_HS_DESC,
+                     "650 HS_DESC CREATED %s UNKNOWN UNKNOWN %s%s\r\n",
+                     onion_address, desc_id,
+                     replica_field ? replica_field : "");
+  tor_free(replica_field);
+}
+
+/** send HS_DESC upload event.
+ *
+ * <b>onion_address</b> is service address.
+ * <b>hs_dir</b> is the description of contacting hs directory.
+ * <b>desc_id</b> is the ID of requested hs descriptor.
+ */
+void
+control_event_hs_descriptor_upload(const char *onion_address,
+                                   const char *id_digest,
+                                   const char *desc_id,
+                                   const char *hsdir_index)
+{
+  char *hsdir_index_field = NULL;
+
+  if (BUG(!onion_address || !id_digest || !desc_id)) {
+    return;
+  }
+
+  if (hsdir_index) {
+    tor_asprintf(&hsdir_index_field, " HSDIR_INDEX=%s", hsdir_index);
+  }
+
+  send_control_event(EVENT_HS_DESC,
+                     "650 HS_DESC UPLOAD %s UNKNOWN %s %s%s\r\n",
+                     onion_address,
+                     node_describe_longname_by_id(id_digest),
+                     desc_id,
+                     hsdir_index_field ? hsdir_index_field : "");
+  tor_free(hsdir_index_field);
+}
+
+/** send HS_DESC event after got response from hs directory.
+ *
+ * NOTE: this is an internal function used by following functions:
+ * control_event_hsv2_descriptor_received
+ * control_event_hsv2_descriptor_failed
+ * control_event_hsv3_descriptor_failed
+ *
+ * So do not call this function directly.
+ */
+static void
+event_hs_descriptor_receive_end(const char *action,
+                                const char *onion_address,
+                                const char *desc_id,
+                                rend_auth_type_t auth_type,
+                                const char *hsdir_id_digest,
+                                const char *reason)
+{
+  char *reason_field = NULL;
+
+  if (BUG(!action || !onion_address)) {
+    return;
+  }
+
+  if (reason) {
+    tor_asprintf(&reason_field, " REASON=%s", reason);
+  }
+
+  send_control_event(EVENT_HS_DESC,
+                     "650 HS_DESC %s %s %s %s%s%s\r\n",
+                     action,
+                     rend_hsaddress_str_or_unknown(onion_address),
+                     rend_auth_type_to_string(auth_type),
+                     hsdir_id_digest ?
+                        node_describe_longname_by_id(hsdir_id_digest) :
+                        "UNKNOWN",
+                     desc_id ? desc_id : "",
+                     reason_field ? reason_field : "");
+
+  tor_free(reason_field);
+}
+
+/** send HS_DESC event after got response from hs directory.
+ *
+ * NOTE: this is an internal function used by following functions:
+ * control_event_hs_descriptor_uploaded
+ * control_event_hs_descriptor_upload_failed
+ *
+ * So do not call this function directly.
+ */
+void
+control_event_hs_descriptor_upload_end(const char *action,
+                                       const char *onion_address,
+                                       const char *id_digest,
+                                       const char *reason)
+{
+  char *reason_field = NULL;
+
+  if (BUG(!action || !id_digest)) {
+    return;
+  }
+
+  if (reason) {
+    tor_asprintf(&reason_field, " REASON=%s", reason);
+  }
+
+  send_control_event(EVENT_HS_DESC,
+                     "650 HS_DESC %s %s UNKNOWN %s%s\r\n",
+                     action,
+                     rend_hsaddress_str_or_unknown(onion_address),
+                     node_describe_longname_by_id(id_digest),
+                     reason_field ? reason_field : "");
+
+  tor_free(reason_field);
+}
+
+/** For an HS descriptor query <b>rend_data</b>, using the
+ * <b>onion_address</b> and HSDir fingerprint <b>hsdir_fp</b>, find out
+ * which descriptor ID in the query is the right one.
+ *
+ * Return a pointer of the binary descriptor ID found in the query's object
+ * or NULL if not found. */
+static const char *
+get_desc_id_from_query(const rend_data_t *rend_data, const char *hsdir_fp)
+{
+  int replica;
+  const char *desc_id = NULL;
+  const rend_data_v2_t *rend_data_v2 = TO_REND_DATA_V2(rend_data);
+
+  /* Possible if the fetch was done using a descriptor ID. This means that
+   * the HSFETCH command was used. */
+  if (!tor_digest_is_zero(rend_data_v2->desc_id_fetch)) {
+    desc_id = rend_data_v2->desc_id_fetch;
+    goto end;
+  }
+
+  /* Without a directory fingerprint at this stage, we can't do much. */
+  if (hsdir_fp == NULL) {
+     goto end;
+  }
+
+  /* OK, we have an onion address so now let's find which descriptor ID
+   * is the one associated with the HSDir fingerprint. */
+  for (replica = 0; replica < REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS;
+       replica++) {
+    const char *digest = rend_data_get_desc_id(rend_data, replica, NULL);
+
+    SMARTLIST_FOREACH_BEGIN(rend_data->hsdirs_fp, char *, fingerprint) {
+      if (tor_memcmp(fingerprint, hsdir_fp, DIGEST_LEN) == 0) {
+        /* Found it! This descriptor ID is the right one. */
+        desc_id = digest;
+        goto end;
+      }
+    } SMARTLIST_FOREACH_END(fingerprint);
+  }
+
+ end:
+  return desc_id;
+}
+
+/** send HS_DESC RECEIVED event
+ *
+ * called when we successfully received a hidden service descriptor.
+ */
+void
+control_event_hsv2_descriptor_received(const char *onion_address,
+                                       const rend_data_t *rend_data,
+                                       const char *hsdir_id_digest)
+{
+  char *desc_id_field = NULL;
+  const char *desc_id;
+
+  if (BUG(!rend_data || !hsdir_id_digest || !onion_address)) {
+    return;
+  }
+
+  desc_id = get_desc_id_from_query(rend_data, hsdir_id_digest);
+  if (desc_id != NULL) {
+    char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
+    /* Set the descriptor ID digest to base32 so we can send it. */
+    base32_encode(desc_id_base32, sizeof(desc_id_base32), desc_id,
+                  DIGEST_LEN);
+    /* Extra whitespace is needed before the value. */
+    tor_asprintf(&desc_id_field, " %s", desc_id_base32);
+  }
+
+  event_hs_descriptor_receive_end("RECEIVED", onion_address, desc_id_field,
+                                  TO_REND_DATA_V2(rend_data)->auth_type,
+                                  hsdir_id_digest, NULL);
+  tor_free(desc_id_field);
+}
+
+/* Send HS_DESC RECEIVED event
+ *
+ * Called when we successfully received a hidden service descriptor. */
+void
+control_event_hsv3_descriptor_received(const char *onion_address,
+                                       const char *desc_id,
+                                       const char *hsdir_id_digest)
+{
+  char *desc_id_field = NULL;
+
+  if (BUG(!onion_address || !desc_id || !hsdir_id_digest)) {
+    return;
+  }
+
+  /* Because DescriptorID is an optional positional value, we need to add a
+   * whitespace before in order to not be next to the HsDir value. */
+  tor_asprintf(&desc_id_field, " %s", desc_id);
+
+  event_hs_descriptor_receive_end("RECEIVED", onion_address, desc_id_field,
+                                  REND_NO_AUTH, hsdir_id_digest, NULL);
+  tor_free(desc_id_field);
+}
+
+/** send HS_DESC UPLOADED event
+ *
+ * called when we successfully uploaded a hidden service descriptor.
+ */
+void
+control_event_hs_descriptor_uploaded(const char *id_digest,
+                                     const char *onion_address)
+{
+  if (BUG(!id_digest)) {
+    return;
+  }
+
+  control_event_hs_descriptor_upload_end("UPLOADED", onion_address,
+                                         id_digest, NULL);
+}
+
+/** Send HS_DESC event to inform controller that query <b>rend_data</b>
+ * failed to retrieve hidden service descriptor from directory identified by
+ * <b>id_digest</b>. If NULL, "UNKNOWN" is used. If <b>reason</b> is not NULL,
+ * add it to REASON= field.
+ */
+void
+control_event_hsv2_descriptor_failed(const rend_data_t *rend_data,
+                                     const char *hsdir_id_digest,
+                                     const char *reason)
+{
+  char *desc_id_field = NULL;
+  const char *desc_id;
+
+  if (BUG(!rend_data)) {
+    return;
+  }
+
+  desc_id = get_desc_id_from_query(rend_data, hsdir_id_digest);
+  if (desc_id != NULL) {
+    char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
+    /* Set the descriptor ID digest to base32 so we can send it. */
+    base32_encode(desc_id_base32, sizeof(desc_id_base32), desc_id,
+                  DIGEST_LEN);
+    /* Extra whitespace is needed before the value. */
+    tor_asprintf(&desc_id_field, " %s", desc_id_base32);
+  }
+
+  event_hs_descriptor_receive_end("FAILED", rend_data_get_address(rend_data),
+                                  desc_id_field,
+                                  TO_REND_DATA_V2(rend_data)->auth_type,
+                                  hsdir_id_digest, reason);
+  tor_free(desc_id_field);
+}
+
+/** Send HS_DESC event to inform controller that the query to
+ * <b>onion_address</b> failed to retrieve hidden service descriptor
+ * <b>desc_id</b> from directory identified by <b>hsdir_id_digest</b>. If
+ * NULL, "UNKNOWN" is used.  If <b>reason</b> is not NULL, add it to REASON=
+ * field. */
+void
+control_event_hsv3_descriptor_failed(const char *onion_address,
+                                     const char *desc_id,
+                                     const char *hsdir_id_digest,
+                                     const char *reason)
+{
+  char *desc_id_field = NULL;
+
+  if (BUG(!onion_address || !desc_id || !reason)) {
+    return;
+  }
+
+  /* Because DescriptorID is an optional positional value, we need to add a
+   * whitespace before in order to not be next to the HsDir value. */
+  tor_asprintf(&desc_id_field, " %s", desc_id);
+
+  event_hs_descriptor_receive_end("FAILED", onion_address, desc_id_field,
+                                  REND_NO_AUTH, hsdir_id_digest, reason);
+  tor_free(desc_id_field);
+}
+
+/** Send HS_DESC_CONTENT event after completion of a successful fetch
+ * from hs directory. If <b>hsdir_id_digest</b> is NULL, it is replaced
+ * by "UNKNOWN". If <b>content</b> is NULL, it is replaced by an empty
+ * string. The  <b>onion_address</b> or <b>desc_id</b> set to NULL will
+ * not trigger the control event. */
+void
+control_event_hs_descriptor_content(const char *onion_address,
+                                    const char *desc_id,
+                                    const char *hsdir_id_digest,
+                                    const char *content)
+{
+  static const char *event_name = "HS_DESC_CONTENT";
+  char *esc_content = NULL;
+
+  if (!onion_address || !desc_id) {
+    log_warn(LD_BUG, "Called with onion_address==%p, desc_id==%p, ",
+             onion_address, desc_id);
+    return;
+  }
+
+  if (content == NULL) {
+    /* Point it to empty content so it can still be escaped. */
+    content = "";
+  }
+  write_escaped_data(content, strlen(content), &esc_content);
+
+  send_control_event(EVENT_HS_DESC_CONTENT,
+                     "650+%s %s %s %s\r\n%s650 OK\r\n",
+                     event_name,
+                     rend_hsaddress_str_or_unknown(onion_address),
+                     desc_id,
+                     hsdir_id_digest ?
+                        node_describe_longname_by_id(hsdir_id_digest) :
+                        "UNKNOWN",
+                     esc_content);
+  tor_free(esc_content);
+}
+
+/** Send HS_DESC event to inform controller upload of hidden service
+ * descriptor identified by <b>id_digest</b> failed. If <b>reason</b>
+ * is not NULL, add it to REASON= field.
+ */
+void
+control_event_hs_descriptor_upload_failed(const char *id_digest,
+                                          const char *onion_address,
+                                          const char *reason)
+{
+  if (BUG(!id_digest)) {
+    return;
+  }
+  control_event_hs_descriptor_upload_end("FAILED", onion_address,
+                                         id_digest, reason);
+}
+
+void
+control_events_free_all(void)
+{
+  smartlist_t *queued_events = NULL;
+
+  stats_prev_n_read = stats_prev_n_written = 0;
+
+  if (queued_control_events_lock) {
+    tor_mutex_acquire(queued_control_events_lock);
+    flush_queued_event_pending = 0;
+    queued_events = queued_control_events;
+    queued_control_events = NULL;
+    tor_mutex_release(queued_control_events_lock);
+  }
+  if (queued_events) {
+    SMARTLIST_FOREACH(queued_events, queued_event_t *, ev,
+                      queued_event_free(ev));
+    smartlist_free(queued_events);
+  }
+  if (flush_queued_events_event) {
+    mainloop_event_free(flush_queued_events_event);
+    flush_queued_events_event = NULL;
+  }
+  global_event_mask = 0;
+  disable_log_messages = 0;
+}
+
+#ifdef TOR_UNIT_TESTS
+/* For testing: change the value of global_event_mask */
+void
+control_testing_set_global_event_mask(uint64_t mask)
+{
+  global_event_mask = mask;
+}
+#endif /* defined(TOR_UNIT_TESTS) */
diff --git a/src/feature/control/control_events.h b/src/feature/control/control_events.h
new file mode 100644
index 000000000..34986fdb8
--- /dev/null
+++ b/src/feature/control/control_events.h
@@ -0,0 +1,352 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_events.h
+ * \brief Header file for control_events.c.
+ **/
+
+#ifndef TOR_CONTROL_EVENTS_H
+#define TOR_CONTROL_EVENTS_H
+
+#include "core/or/ocirc_event.h"
+
+/** Used to indicate the type of a CIRC_MINOR event passed to the controller.
+ * The various types are defined in control-spec.txt . */
+typedef enum circuit_status_minor_event_t {
+  CIRC_MINOR_EVENT_PURPOSE_CHANGED,
+  CIRC_MINOR_EVENT_CANNIBALIZED,
+} circuit_status_minor_event_t;
+
+#include "core/or/orconn_event.h"
+
+/** Used to indicate the type of a stream event passed to the controller.
+ * The various types are defined in control-spec.txt */
+typedef enum stream_status_event_t {
+  STREAM_EVENT_SENT_CONNECT = 0,
+  STREAM_EVENT_SENT_RESOLVE = 1,
+  STREAM_EVENT_SUCCEEDED    = 2,
+  STREAM_EVENT_FAILED       = 3,
+  STREAM_EVENT_CLOSED       = 4,
+  STREAM_EVENT_NEW          = 5,
+  STREAM_EVENT_NEW_RESOLVE  = 6,
+  STREAM_EVENT_FAILED_RETRIABLE = 7,
+  STREAM_EVENT_REMAP        = 8
+} stream_status_event_t;
+
+/** Used to indicate the type of a buildtime event */
+typedef enum buildtimeout_set_event_t {
+  BUILDTIMEOUT_SET_EVENT_COMPUTED  = 0,
+  BUILDTIMEOUT_SET_EVENT_RESET     = 1,
+  BUILDTIMEOUT_SET_EVENT_SUSPENDED = 2,
+  BUILDTIMEOUT_SET_EVENT_DISCARD = 3,
+  BUILDTIMEOUT_SET_EVENT_RESUME = 4
+} buildtimeout_set_event_t;
+
+/** Enum describing various stages of bootstrapping, for use with controller
+ * bootstrap status events. The values range from 0 to 100. */
+typedef enum {
+  BOOTSTRAP_STATUS_UNDEF=-1,
+  BOOTSTRAP_STATUS_STARTING=0,
+
+  /* Initial connection to any relay */
+
+  BOOTSTRAP_STATUS_CONN_PT=1,
+  BOOTSTRAP_STATUS_CONN_DONE_PT=2,
+  BOOTSTRAP_STATUS_CONN_PROXY=3,
+  BOOTSTRAP_STATUS_CONN_DONE_PROXY=4,
+  BOOTSTRAP_STATUS_CONN=5,
+  BOOTSTRAP_STATUS_CONN_DONE=10,
+  BOOTSTRAP_STATUS_HANDSHAKE=14,
+  BOOTSTRAP_STATUS_HANDSHAKE_DONE=15,
+
+  /* Loading directory info */
+
+  BOOTSTRAP_STATUS_ONEHOP_CREATE=20,
+  BOOTSTRAP_STATUS_REQUESTING_STATUS=25,
+  BOOTSTRAP_STATUS_LOADING_STATUS=30,
+  BOOTSTRAP_STATUS_LOADING_KEYS=40,
+  BOOTSTRAP_STATUS_REQUESTING_DESCRIPTORS=45,
+  BOOTSTRAP_STATUS_LOADING_DESCRIPTORS=50,
+  BOOTSTRAP_STATUS_ENOUGH_DIRINFO=75,
+
+  /* Connecting to a relay for AP circuits */
+
+  BOOTSTRAP_STATUS_AP_CONN_PT=76,
+  BOOTSTRAP_STATUS_AP_CONN_DONE_PT=77,
+  BOOTSTRAP_STATUS_AP_CONN_PROXY=78,
+  BOOTSTRAP_STATUS_AP_CONN_DONE_PROXY=79,
+  BOOTSTRAP_STATUS_AP_CONN=80,
+  BOOTSTRAP_STATUS_AP_CONN_DONE=85,
+  BOOTSTRAP_STATUS_AP_HANDSHAKE=89,
+  BOOTSTRAP_STATUS_AP_HANDSHAKE_DONE=90,
+
+  /* Creating AP circuits */
+
+  BOOTSTRAP_STATUS_CIRCUIT_CREATE=95,
+  BOOTSTRAP_STATUS_DONE=100
+} bootstrap_status_t;
+
+/** Reason for remapping an AP connection's address: we have a cached
+ * answer. */
+#define REMAP_STREAM_SOURCE_CACHE 1
+/** Reason for remapping an AP connection's address: the exit node told us an
+ * answer. */
+#define REMAP_STREAM_SOURCE_EXIT 2
+
+void control_initialize_event_queue(void);
+
+void control_update_global_event_mask(void);
+void control_adjust_event_log_severity(void);
+
+#define EVENT_NS 0x000F
+int control_event_is_interesting(int event);
+
+void control_per_second_events(void);
+int control_any_per_second_event_enabled(void);
+
+int control_event_circuit_status(origin_circuit_t *circ,
+                                 circuit_status_event_t e, int reason);
+int control_event_circuit_purpose_changed(origin_circuit_t *circ,
+                                          int old_purpose);
+int control_event_circuit_cannibalized(origin_circuit_t *circ,
+                                       int old_purpose,
+                                       const struct timeval *old_tv_created);
+int control_event_stream_status(entry_connection_t *conn,
+                                stream_status_event_t e,
+                                int reason);
+int control_event_or_conn_status(or_connection_t *conn,
+                                 or_conn_status_event_t e, int reason);
+int control_event_bandwidth_used(uint32_t n_read, uint32_t n_written);
+int control_event_stream_bandwidth(edge_connection_t *edge_conn);
+int control_event_stream_bandwidth_used(void);
+int control_event_circ_bandwidth_used(void);
+int control_event_circ_bandwidth_used_for_circ(origin_circuit_t *ocirc);
+int control_event_conn_bandwidth(connection_t *conn);
+int control_event_conn_bandwidth_used(void);
+int control_event_circuit_cell_stats(void);
+void control_event_logmsg(int severity, log_domain_mask_t domain,
+                          const char *msg);
+void control_event_logmsg_pending(void);
+int control_event_descriptors_changed(smartlist_t *routers);
+int control_event_address_mapped(const char *from, const char *to,
+                                 time_t expires, const char *error,
+                                 const int cached);
+int control_event_my_descriptor_changed(void);
+int control_event_network_liveness_update(int liveness);
+int control_event_networkstatus_changed(smartlist_t *statuses);
+
+int control_event_newconsensus(const networkstatus_t *consensus);
+int control_event_networkstatus_changed_single(const routerstatus_t *rs);
+int control_event_general_status(int severity, const char *format, ...)
+  CHECK_PRINTF(2,3);
+int control_event_client_status(int severity, const char *format, ...)
+  CHECK_PRINTF(2,3);
+int control_event_server_status(int severity, const char *format, ...)
+  CHECK_PRINTF(2,3);
+
+int control_event_general_error(const char *format, ...)
+  CHECK_PRINTF(1,2);
+int control_event_client_error(const char *format, ...)
+  CHECK_PRINTF(1,2);
+int control_event_server_error(const char *format, ...)
+  CHECK_PRINTF(1,2);
+
+int control_event_guard(const char *nickname, const char *digest,
+                        const char *status);
+int control_event_conf_changed(const smartlist_t *elements);
+int control_event_buildtimeout_set(buildtimeout_set_event_t type,
+                                   const char *args);
+int control_event_signal(uintptr_t signal);
+
+void control_event_bootstrap(bootstrap_status_t status, int progress);
+MOCK_DECL(void, control_event_bootstrap_prob_or,(const char *warn,
+                                                 int reason,
+                                                 or_connection_t *or_conn));
+void control_event_boot_dir(bootstrap_status_t status, int progress);
+void control_event_boot_first_orconn(void);
+void control_event_bootstrap_problem(const char *warn, const char *reason,
+                                     const connection_t *conn, int dowarn);
+char *control_event_boot_last_msg(void);
+void control_event_bootstrap_reset(void);
+
+void control_event_clients_seen(const char *controller_str);
+void control_event_transport_launched(const char *mode,
+                                      const char *transport_name,
+                                      tor_addr_t *addr, uint16_t port);
+void control_event_pt_log(const char *log);
+void control_event_pt_status(const char *status);
+
+void control_event_hs_descriptor_requested(const char *onion_address,
+                                           rend_auth_type_t auth_type,
+                                           const char *id_digest,
+                                           const char *desc_id,
+                                           const char *hsdir_index);
+void control_event_hs_descriptor_created(const char *onion_address,
+                                         const char *desc_id,
+                                         int replica);
+void control_event_hs_descriptor_upload(const char *onion_address,
+                                        const char *desc_id,
+                                        const char *hs_dir,
+                                        const char *hsdir_index);
+void control_event_hs_descriptor_upload_end(const char *action,
+                                            const char *onion_address,
+                                            const char *hs_dir,
+                                            const char *reason);
+void control_event_hs_descriptor_uploaded(const char *hs_dir,
+                                          const char *onion_address);
+/* Hidden service v2 HS_DESC specific. */
+void control_event_hsv2_descriptor_failed(const rend_data_t *rend_data,
+                                          const char *id_digest,
+                                          const char *reason);
+void control_event_hsv2_descriptor_received(const char *onion_address,
+                                            const rend_data_t *rend_data,
+                                            const char *id_digest);
+/* Hidden service v3 HS_DESC specific. */
+void control_event_hsv3_descriptor_failed(const char *onion_address,
+                                          const char *desc_id,
+                                          const char *hsdir_id_digest,
+                                          const char *reason);
+void control_event_hsv3_descriptor_received(const char *onion_address,
+                                            const char *desc_id,
+                                            const char *hsdir_id_digest);
+void control_event_hs_descriptor_upload_failed(const char *hs_dir,
+                                               const char *onion_address,
+                                               const char *reason);
+void control_event_hs_descriptor_content(const char *onion_address,
+                                         const char *desc_id,
+                                         const char *hsdir_fp,
+                                         const char *content);
+
+void control_events_free_all(void);
+
+#ifdef CONTROL_MODULE_PRIVATE
+char *get_bw_samples(void);
+#endif /* defined(CONTROL_MODULE_PRIVATE) */
+
+#ifdef CONTROL_EVENTS_PRIVATE
+/** Bitfield: The bit 1<<e is set if <b>any</b> open control
+ * connection is interested in events of type <b>e</b>.  We use this
+ * so that we can decide to skip generating event messages that nobody
+ * has interest in without having to walk over the global connection
+ * list to find out.
+ **/
+typedef uint64_t event_mask_t;
+
+/* Recognized asynchronous event types.  It's okay to expand this list
+ * because it is used both as a list of v0 event types, and as indices
+ * into the bitfield to determine which controllers want which events.
+ */
+/* This bitfield has no event zero    0x0000 */
+#define EVENT_MIN_                    0x0001
+#define EVENT_CIRCUIT_STATUS          0x0001
+#define EVENT_STREAM_STATUS           0x0002
+#define EVENT_OR_CONN_STATUS          0x0003
+#define EVENT_BANDWIDTH_USED          0x0004
+#define EVENT_CIRCUIT_STATUS_MINOR    0x0005
+#define EVENT_NEW_DESC                0x0006
+#define EVENT_DEBUG_MSG               0x0007
+#define EVENT_INFO_MSG                0x0008
+#define EVENT_NOTICE_MSG              0x0009
+#define EVENT_WARN_MSG                0x000A
+#define EVENT_ERR_MSG                 0x000B
+#define EVENT_ADDRMAP                 0x000C
+/* There was an AUTHDIR_NEWDESCS event, but it no longer exists.  We
+   can reclaim 0x000D. */
+#define EVENT_DESCCHANGED             0x000E
+/* Exposed above */
+// #define EVENT_NS                   0x000F
+#define EVENT_STATUS_CLIENT           0x0010
+#define EVENT_STATUS_SERVER           0x0011
+#define EVENT_STATUS_GENERAL          0x0012
+#define EVENT_GUARD                   0x0013
+#define EVENT_STREAM_BANDWIDTH_USED   0x0014
+#define EVENT_CLIENTS_SEEN            0x0015
+#define EVENT_NEWCONSENSUS            0x0016
+#define EVENT_BUILDTIMEOUT_SET        0x0017
+#define EVENT_GOT_SIGNAL              0x0018
+#define EVENT_CONF_CHANGED            0x0019
+#define EVENT_CONN_BW                 0x001A
+#define EVENT_CELL_STATS              0x001B
+/* UNUSED :                           0x001C */
+#define EVENT_CIRC_BANDWIDTH_USED     0x001D
+#define EVENT_TRANSPORT_LAUNCHED      0x0020
+#define EVENT_HS_DESC                 0x0021
+#define EVENT_HS_DESC_CONTENT         0x0022
+#define EVENT_NETWORK_LIVENESS        0x0023
+#define EVENT_PT_LOG                  0x0024
+#define EVENT_PT_STATUS               0x0025
+#define EVENT_MAX_                    0x0025
+
+/* sizeof(control_connection_t.event_mask) in bits, currently a uint64_t */
+#define EVENT_CAPACITY_               0x0040
+
+/* If EVENT_MAX_ ever hits 0x0040, we need to make the mask into a
+ * different structure, as it can only handle a maximum left shift of 1<<63. */
+
+#if EVENT_MAX_ >= EVENT_CAPACITY_
+#error control_connection_t.event_mask has an event greater than its capacity
+#endif
+
+#define EVENT_MASK_(e)               (((uint64_t)1)<<(e))
+
+#define EVENT_MASK_NONE_             ((uint64_t)0x0)
+
+#define EVENT_MASK_ABOVE_MIN_        ((~((uint64_t)0x0)) << EVENT_MIN_)
+#define EVENT_MASK_BELOW_MAX_        ((~((uint64_t)0x0)) \
+                                      >> (EVENT_CAPACITY_ - EVENT_MAX_ \
+                                          - EVENT_MIN_))
+
+#define EVENT_MASK_ALL_              (EVENT_MASK_ABOVE_MIN_ \
+                                      & EVENT_MASK_BELOW_MAX_)
+
+/** Helper structure: temporarily stores cell statistics for a circuit. */
+typedef struct cell_stats_t {
+  /** Number of cells added in app-ward direction by command. */
+  uint64_t added_cells_appward[CELL_COMMAND_MAX_ + 1];
+  /** Number of cells added in exit-ward direction by command. */
+  uint64_t added_cells_exitward[CELL_COMMAND_MAX_ + 1];
+  /** Number of cells removed in app-ward direction by command. */
+  uint64_t removed_cells_appward[CELL_COMMAND_MAX_ + 1];
+  /** Number of cells removed in exit-ward direction by command. */
+  uint64_t removed_cells_exitward[CELL_COMMAND_MAX_ + 1];
+  /** Total waiting time of cells in app-ward direction by command. */
+  uint64_t total_time_appward[CELL_COMMAND_MAX_ + 1];
+  /** Total waiting time of cells in exit-ward direction by command. */
+  uint64_t total_time_exitward[CELL_COMMAND_MAX_ + 1];
+} cell_stats_t;
+
+void sum_up_cell_stats_by_command(circuit_t *circ,
+                                  cell_stats_t *cell_stats);
+void append_cell_stats_by_command(smartlist_t *event_parts,
+                                  const char *key,
+                                  const uint64_t *include_if_non_zero,
+                                  const uint64_t *number_to_include);
+void format_cell_stats(char **event_string, circuit_t *circ,
+                       cell_stats_t *cell_stats);
+
+/** Helper structure: maps event values to their names. */
+struct control_event_t {
+  uint16_t event_code;
+  const char *event_name;
+};
+
+extern const struct control_event_t control_event_table[];
+
+#ifdef TOR_UNIT_TESTS
+MOCK_DECL(STATIC void,
+          send_control_event_string,(uint16_t event, const char *msg));
+
+MOCK_DECL(STATIC void,
+          queue_control_event_string,(uint16_t event, char *msg));
+
+void control_testing_set_global_event_mask(uint64_t mask);
+
+#endif /* defined(TOR_UNIT_TESTS) */
+
+#endif /* defined(CONTROL_EVENTS_PRIVATE) */
+
+#endif /* !defined(TOR_CONTROL_EVENTS_H) */
diff --git a/src/feature/control/control_fmt.c b/src/feature/control/control_fmt.c
new file mode 100644
index 000000000..e0e77eb2d
--- /dev/null
+++ b/src/feature/control/control_fmt.c
@@ -0,0 +1,181 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_fmt.c
+ * \brief Formatting functions for controller data.
+ */
+
+#include "core/or/or.h"
+
+#include "core/mainloop/connection.h"
+#include "core/or/circuitbuild.h"
+#include "core/or/circuitlist.h"
+#include "core/or/connection_edge.h"
+#include "feature/control/control_fmt.h"
+#include "feature/control/control_proto.h"
+#include "feature/nodelist/nodelist.h"
+
+#include "core/or/cpath_build_state_st.h"
+#include "core/or/entry_connection_st.h"
+#include "core/or/or_connection_st.h"
+#include "core/or/origin_circuit_st.h"
+#include "core/or/socks_request_st.h"
+#include "feature/control/control_connection_st.h"
+
+/** Given an AP connection <b>conn</b> and a <b>len</b>-character buffer
+ * <b>buf</b>, determine the address:port combination requested on
+ * <b>conn</b>, and write it to <b>buf</b>.  Return 0 on success, -1 on
+ * failure. */
+int
+write_stream_target_to_buf(entry_connection_t *conn, char *buf, size_t len)
+{
+  char buf2[256];
+  if (conn->chosen_exit_name)
+    if (tor_snprintf(buf2, sizeof(buf2), ".%s.exit", conn->chosen_exit_name)<0)
+      return -1;
+  if (!conn->socks_request)
+    return -1;
+  if (tor_snprintf(buf, len, "%s%s%s:%d",
+               conn->socks_request->address,
+               conn->chosen_exit_name ? buf2 : "",
+               !conn->chosen_exit_name && connection_edge_is_rendezvous_stream(
+                                     ENTRY_TO_EDGE_CONN(conn)) ? ".onion" : "",
+               conn->socks_request->port)<0)
+    return -1;
+  return 0;
+}
+
+/** Figure out the best name for the target router of an OR connection
+ * <b>conn</b>, and write it into the <b>len</b>-character buffer
+ * <b>name</b>. */
+void
+orconn_target_get_name(char *name, size_t len, or_connection_t *conn)
+{
+  const node_t *node = node_get_by_id(conn->identity_digest);
+  if (node) {
+    tor_assert(len > MAX_VERBOSE_NICKNAME_LEN);
+    node_get_verbose_nickname(node, name);
+  } else if (! tor_digest_is_zero(conn->identity_digest)) {
+    name[0] = '$';
+    base16_encode(name+1, len-1, conn->identity_digest,
+                  DIGEST_LEN);
+  } else {
+    tor_snprintf(name, len, "%s:%d",
+                 conn->base_.address, conn->base_.port);
+  }
+}
+
+/** Allocate and return a description of <b>circ</b>'s current status,
+ * including its path (if any). */
+char *
+circuit_describe_status_for_controller(origin_circuit_t *circ)
+{
+  char *rv;
+  smartlist_t *descparts = smartlist_new();
+
+  {
+    char *vpath = circuit_list_path_for_controller(circ);
+    if (*vpath) {
+      smartlist_add(descparts, vpath);
+    } else {
+      tor_free(vpath); /* empty path; don't put an extra space in the result */
+    }
+  }
+
+  {
+    cpath_build_state_t *build_state = circ->build_state;
+    smartlist_t *flaglist = smartlist_new();
+    char *flaglist_joined;
+
+    if (build_state->onehop_tunnel)
+      smartlist_add(flaglist, (void *)"ONEHOP_TUNNEL");
+    if (build_state->is_internal)
+      smartlist_add(flaglist, (void *)"IS_INTERNAL");
+    if (build_state->need_capacity)
+      smartlist_add(flaglist, (void *)"NEED_CAPACITY");
+    if (build_state->need_uptime)
+      smartlist_add(flaglist, (void *)"NEED_UPTIME");
+
+    /* Only emit a BUILD_FLAGS argument if it will have a non-empty value. */
+    if (smartlist_len(flaglist)) {
+      flaglist_joined = smartlist_join_strings(flaglist, ",", 0, NULL);
+
+      smartlist_add_asprintf(descparts, "BUILD_FLAGS=%s", flaglist_joined);
+
+      tor_free(flaglist_joined);
+    }
+
+    smartlist_free(flaglist);
+  }
+
+  smartlist_add_asprintf(descparts, "PURPOSE=%s",
+                    circuit_purpose_to_controller_string(circ->base_.purpose));
+
+  {
+    const char *hs_state =
+      circuit_purpose_to_controller_hs_state_string(circ->base_.purpose);
+
+    if (hs_state != NULL) {
+      smartlist_add_asprintf(descparts, "HS_STATE=%s", hs_state);
+    }
+  }
+
+  if (circ->rend_data != NULL || circ->hs_ident != NULL) {
+    char addr[HS_SERVICE_ADDR_LEN_BASE32 + 1];
+    const char *onion_address;
+    if (circ->rend_data) {
+      onion_address = rend_data_get_address(circ->rend_data);
+    } else {
+      hs_build_address(&circ->hs_ident->identity_pk, HS_VERSION_THREE, addr);
+      onion_address = addr;
+    }
+    smartlist_add_asprintf(descparts, "REND_QUERY=%s", onion_address);
+  }
+
+  {
+    char tbuf[ISO_TIME_USEC_LEN+1];
+    format_iso_time_nospace_usec(tbuf, &circ->base_.timestamp_created);
+
+    smartlist_add_asprintf(descparts, "TIME_CREATED=%s", tbuf);
+  }
+
+  // Show username and/or password if available.
+  if (circ->socks_username_len > 0) {
+    char* socks_username_escaped = esc_for_log_len(circ->socks_username,
+                                     (size_t) circ->socks_username_len);
+    smartlist_add_asprintf(descparts, "SOCKS_USERNAME=%s",
+                           socks_username_escaped);
+    tor_free(socks_username_escaped);
+  }
+  if (circ->socks_password_len > 0) {
+    char* socks_password_escaped = esc_for_log_len(circ->socks_password,
+                                     (size_t) circ->socks_password_len);
+    smartlist_add_asprintf(descparts, "SOCKS_PASSWORD=%s",
+                           socks_password_escaped);
+    tor_free(socks_password_escaped);
+  }
+
+  rv = smartlist_join_strings(descparts, " ", 0, NULL);
+
+  SMARTLIST_FOREACH(descparts, char *, cp, tor_free(cp));
+  smartlist_free(descparts);
+
+  return rv;
+}
+
+/** Return a longname the node whose identity is <b>id_digest</b>. If
+ * node_get_by_id() returns NULL, base 16 encoding of <b>id_digest</b> is
+ * returned instead.
+ *
+ * This function is not thread-safe.  Each call to this function invalidates
+ * previous values returned by this function.
+ */
+MOCK_IMPL(const char *,
+node_describe_longname_by_id,(const char *id_digest))
+{
+  static char longname[MAX_VERBOSE_NICKNAME_LEN+1];
+  node_get_verbose_nickname_by_id(id_digest, longname);
+  return longname;
+}
diff --git a/src/feature/control/control_fmt.h b/src/feature/control/control_fmt.h
new file mode 100644
index 000000000..6446e3707
--- /dev/null
+++ b/src/feature/control/control_fmt.h
@@ -0,0 +1,23 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_fmt.h
+ * \brief Header file for control_fmt.c.
+ **/
+
+#ifndef TOR_CONTROL_FMT_H
+#define TOR_CONTROL_FMT_H
+
+int write_stream_target_to_buf(entry_connection_t *conn, char *buf,
+                               size_t len);
+void orconn_target_get_name(char *buf, size_t len,
+                            or_connection_t *conn);
+char *circuit_describe_status_for_controller(origin_circuit_t *circ);
+
+MOCK_DECL(const char *, node_describe_longname_by_id,(const char *id_digest));
+
+#endif /* !defined(TOR_CONTROL_FMT_H) */
diff --git a/src/feature/control/control_getinfo.c b/src/feature/control/control_getinfo.c
new file mode 100644
index 000000000..3e31bb9e8
--- /dev/null
+++ b/src/feature/control/control_getinfo.c
@@ -0,0 +1,1654 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_getinfo.c
+ * \brief Implementation for miscellaneous controller getinfo commands.
+ */
+
+#define CONTROL_EVENTS_PRIVATE
+#define CONTROL_MODULE_PRIVATE
+#define CONTROL_GETINFO_PRIVATE
+
+#include "core/or/or.h"
+#include "app/config/config.h"
+#include "core/mainloop/connection.h"
+#include "core/mainloop/mainloop.h"
+#include "core/or/circuitlist.h"
+#include "core/or/connection_edge.h"
+#include "core/or/connection_or.h"
+#include "core/or/policies.h"
+#include "core/or/versions.h"
+#include "feature/client/addressmap.h"
+#include "feature/client/bridges.h"
+#include "feature/client/entrynodes.h"
+#include "feature/control/control.h"
+#include "feature/control/control_cmd.h"
+#include "feature/control/control_events.h"
+#include "feature/control/control_fmt.h"
+#include "feature/control/control_getinfo.h"
+#include "feature/control/control_proto.h"
+#include "feature/control/fmt_serverstatus.h"
+#include "feature/control/getinfo_geoip.h"
+#include "feature/dircache/dirserv.h"
+#include "feature/dirclient/dirclient.h"
+#include "feature/dirclient/dlstatus.h"
+#include "feature/hibernate/hibernate.h"
+#include "feature/hs/hs_cache.h"
+#include "feature/hs_common/shared_random_client.h"
+#include "feature/nodelist/authcert.h"
+#include "feature/nodelist/microdesc.h"
+#include "feature/nodelist/networkstatus.h"
+#include "feature/nodelist/nodelist.h"
+#include "feature/nodelist/routerinfo.h"
+#include "feature/nodelist/routerlist.h"
+#include "feature/relay/router.h"
+#include "feature/relay/routermode.h"
+#include "feature/relay/selftest.h"
+#include "feature/rend/rendcache.h"
+#include "feature/stats/geoip_stats.h"
+#include "feature/stats/predict_ports.h"
+#include "lib/version/torversion.h"
+
+#include "core/or/entry_connection_st.h"
+#include "core/or/or_connection_st.h"
+#include "core/or/origin_circuit_st.h"
+#include "core/or/socks_request_st.h"
+#include "feature/control/control_connection_st.h"
+#include "feature/control/control_cmd_args_st.h"
+#include "feature/dircache/cached_dir_st.h"
+#include "feature/nodelist/extrainfo_st.h"
+#include "feature/nodelist/microdesc_st.h"
+#include "feature/nodelist/networkstatus_st.h"
+#include "feature/nodelist/node_st.h"
+#include "feature/nodelist/routerinfo_st.h"
+#include "feature/nodelist/routerlist_st.h"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#ifndef _WIN32
+#include <pwd.h>
+#endif
+
+static char *list_getinfo_options(void);
+static char *download_status_to_string(const download_status_t *dl);
+
+/** Implementation helper for GETINFO: knows the answers for various
+ * trivial-to-implement questions. */
+static int
+getinfo_helper_misc(control_connection_t *conn, const char *question,
+                    char **answer, const char **errmsg)
+{
+  (void) conn;
+  if (!strcmp(question, "version")) {
+    *answer = tor_strdup(get_version());
+  } else if (!strcmp(question, "bw-event-cache")) {
+    *answer = get_bw_samples();
+  } else if (!strcmp(question, "config-file")) {
+    const char *a = get_torrc_fname(0);
+    if (a)
+      *answer = tor_strdup(a);
+  } else if (!strcmp(question, "config-defaults-file")) {
+    const char *a = get_torrc_fname(1);
+    if (a)
+      *answer = tor_strdup(a);
+  } else if (!strcmp(question, "config-text")) {
+    *answer = options_dump(get_options(), OPTIONS_DUMP_MINIMAL);
+  } else if (!strcmp(question, "config-can-saveconf")) {
+    *answer = tor_strdup(get_options()->IncludeUsed ? "0" : "1");
+  } else if (!strcmp(question, "info/names")) {
+    *answer = list_getinfo_options();
+  } else if (!strcmp(question, "dormant")) {
+    int dormant = rep_hist_circbuilding_dormant(time(NULL));
+    *answer = tor_strdup(dormant ? "1" : "0");
+  } else if (!strcmp(question, "events/names")) {
+    int i;
+    smartlist_t *event_names = smartlist_new();
+
+    for (i = 0; control_event_table[i].event_name != NULL; ++i) {
+      smartlist_add(event_names, (char *)control_event_table[i].event_name);
+    }
+
+    *answer = smartlist_join_strings(event_names, " ", 0, NULL);
+
+    smartlist_free(event_names);
+  } else if (!strcmp(question, "signal/names")) {
+    smartlist_t *signal_names = smartlist_new();
+    int j;
+    for (j = 0; signal_table[j].signal_name != NULL; ++j) {
+      smartlist_add(signal_names, (char*)signal_table[j].signal_name);
+    }
+
+    *answer = smartlist_join_strings(signal_names, " ", 0, NULL);
+
+    smartlist_free(signal_names);
+  } else if (!strcmp(question, "features/names")) {
+    *answer = tor_strdup("VERBOSE_NAMES EXTENDED_EVENTS");
+  } else if (!strcmp(question, "address")) {
+    uint32_t addr;
+    if (router_pick_published_address(get_options(), &addr, 0) < 0) {
+      *errmsg = "Address unknown";
+      return -1;
+    }
+    *answer = tor_dup_ip(addr);
+  } else if (!strcmp(question, "traffic/read")) {
+    tor_asprintf(answer, "%"PRIu64, (get_bytes_read()));
+  } else if (!strcmp(question, "traffic/written")) {
+    tor_asprintf(answer, "%"PRIu64, (get_bytes_written()));
+  } else if (!strcmp(question, "uptime")) {
+    long uptime_secs = get_uptime();
+    tor_asprintf(answer, "%ld", uptime_secs);
+  } else if (!strcmp(question, "process/pid")) {
+    int myPid = -1;
+
+#ifdef _WIN32
+      myPid = _getpid();
+#else
+      myPid = getpid();
+#endif
+
+    tor_asprintf(answer, "%d", myPid);
+  } else if (!strcmp(question, "process/uid")) {
+#ifdef _WIN32
+      *answer = tor_strdup("-1");
+#else
+      int myUid = geteuid();
+      tor_asprintf(answer, "%d", myUid);
+#endif /* defined(_WIN32) */
+  } else if (!strcmp(question, "process/user")) {
+#ifdef _WIN32
+      *answer = tor_strdup("");
+#else
+      int myUid = geteuid();
+      const struct passwd *myPwEntry = tor_getpwuid(myUid);
+
+      if (myPwEntry) {
+        *answer = tor_strdup(myPwEntry->pw_name);
+      } else {
+        *answer = tor_strdup("");
+      }
+#endif /* defined(_WIN32) */
+  } else if (!strcmp(question, "process/descriptor-limit")) {
+    int max_fds = get_max_sockets();
+    tor_asprintf(answer, "%d", max_fds);
+  } else if (!strcmp(question, "limits/max-mem-in-queues")) {
+    tor_asprintf(answer, "%"PRIu64,
+                 (get_options()->MaxMemInQueues));
+  } else if (!strcmp(question, "fingerprint")) {
+    crypto_pk_t *server_key;
+    if (!server_mode(get_options())) {
+      *errmsg = "Not running in server mode";
+      return -1;
+    }
+    server_key = get_server_identity_key();
+    *answer = tor_malloc(HEX_DIGEST_LEN+1);
+    crypto_pk_get_fingerprint(server_key, *answer, 0);
+  }
+  return 0;
+}
+
+/** Awful hack: return a newly allocated string based on a routerinfo and
+ * (possibly) an extrainfo, sticking the read-history and write-history from
+ * <b>ei</b> into the resulting string.  The thing you get back won't
+ * necessarily have a valid signature.
+ *
+ * New code should never use this; it's for backward compatibility.
+ *
+ * NOTE: <b>ri_body</b> is as returned by signed_descriptor_get_body: it might
+ * not be NUL-terminated. */
+static char *
+munge_extrainfo_into_routerinfo(const char *ri_body,
+                                const signed_descriptor_t *ri,
+                                const signed_descriptor_t *ei)
+{
+  char *out = NULL, *outp;
+  int i;
+  const char *router_sig;
+  const char *ei_body = signed_descriptor_get_body(ei);
+  size_t ri_len = ri->signed_descriptor_len;
+  size_t ei_len = ei->signed_descriptor_len;
+  if (!ei_body)
+    goto bail;
+
+  outp = out = tor_malloc(ri_len+ei_len+1);
+  if (!(router_sig = tor_memstr(ri_body, ri_len, "\nrouter-signature")))
+    goto bail;
+  ++router_sig;
+  memcpy(out, ri_body, router_sig-ri_body);
+  outp += router_sig-ri_body;
+
+  for (i=0; i < 2; ++i) {
+    const char *kwd = i ? "\nwrite-history " : "\nread-history ";
+    const char *cp, *eol;
+    if (!(cp = tor_memstr(ei_body, ei_len, kwd)))
+      continue;
+    ++cp;
+    if (!(eol = memchr(cp, '\n', ei_len - (cp-ei_body))))
+      continue;
+    memcpy(outp, cp, eol-cp+1);
+    outp += eol-cp+1;
+  }
+  memcpy(outp, router_sig, ri_len - (router_sig-ri_body));
+  *outp++ = '\0';
+  tor_assert(outp-out < (int)(ri_len+ei_len+1));
+
+  return out;
+ bail:
+  tor_free(out);
+  return tor_strndup(ri_body, ri->signed_descriptor_len);
+}
+
+/** Implementation helper for GETINFO: answers requests for information about
+ * which ports are bound. */
+static int
+getinfo_helper_listeners(control_connection_t *control_conn,
+                         const char *question,
+                         char **answer, const char **errmsg)
+{
+  int type;
+  smartlist_t *res;
+
+  (void)control_conn;
+  (void)errmsg;
+
+  if (!strcmp(question, "net/listeners/or"))
+    type = CONN_TYPE_OR_LISTENER;
+  else if (!strcmp(question, "net/listeners/extor"))
+    type = CONN_TYPE_EXT_OR_LISTENER;
+  else if (!strcmp(question, "net/listeners/dir"))
+    type = CONN_TYPE_DIR_LISTENER;
+  else if (!strcmp(question, "net/listeners/socks"))
+    type = CONN_TYPE_AP_LISTENER;
+  else if (!strcmp(question, "net/listeners/trans"))
+    type = CONN_TYPE_AP_TRANS_LISTENER;
+  else if (!strcmp(question, "net/listeners/natd"))
+    type = CONN_TYPE_AP_NATD_LISTENER;
+  else if (!strcmp(question, "net/listeners/httptunnel"))
+    type = CONN_TYPE_AP_HTTP_CONNECT_LISTENER;
+  else if (!strcmp(question, "net/listeners/dns"))
+    type = CONN_TYPE_AP_DNS_LISTENER;
+  else if (!strcmp(question, "net/listeners/control"))
+    type = CONN_TYPE_CONTROL_LISTENER;
+  else
+    return 0; /* unknown key */
+
+  res = smartlist_new();
+  SMARTLIST_FOREACH_BEGIN(get_connection_array(), connection_t *, conn) {
+    struct sockaddr_storage ss;
+    socklen_t ss_len = sizeof(ss);
+
+    if (conn->type != type || conn->marked_for_close || !SOCKET_OK(conn->s))
+      continue;
+
+    if (getsockname(conn->s, (struct sockaddr *)&ss, &ss_len) < 0) {
+      smartlist_add_asprintf(res, "%s:%d", conn->address, (int)conn->port);
+    } else {
+      char *tmp = tor_sockaddr_to_str((struct sockaddr *)&ss);
+      smartlist_add(res, esc_for_log(tmp));
+      tor_free(tmp);
+    }
+
+  } SMARTLIST_FOREACH_END(conn);
+
+  *answer = smartlist_join_strings(res, " ", 0, NULL);
+
+  SMARTLIST_FOREACH(res, char *, cp, tor_free(cp));
+  smartlist_free(res);
+  return 0;
+}
+
+/** Implementation helper for GETINFO: answers requests for information about
+ * the current time in both local and UTC forms. */
+STATIC int
+getinfo_helper_current_time(control_connection_t *control_conn,
+                         const char *question,
+                         char **answer, const char **errmsg)
+{
+  (void)control_conn;
+  (void)errmsg;
+
+  struct timeval now;
+  tor_gettimeofday(&now);
+  char timebuf[ISO_TIME_LEN+1];
+
+  if (!strcmp(question, "current-time/local"))
+    format_local_iso_time_nospace(timebuf, (time_t)now.tv_sec);
+  else if (!strcmp(question, "current-time/utc"))
+    format_iso_time_nospace(timebuf, (time_t)now.tv_sec);
+  else
+    return 0;
+
+  *answer = tor_strdup(timebuf);
+  return 0;
+}
+
+/** Implementation helper for GETINFO: knows the answers for questions about
+ * directory information. */
+STATIC int
+getinfo_helper_dir(control_connection_t *control_conn,
+                   const char *question, char **answer,
+                   const char **errmsg)
+{
+  (void) control_conn;
+  if (!strcmpstart(question, "desc/id/")) {
+    const routerinfo_t *ri = NULL;
+    const node_t *node = node_get_by_hex_id(question+strlen("desc/id/"), 0);
+    if (node)
+      ri = node->ri;
+    if (ri) {
+      const char *body = signed_descriptor_get_body(&ri->cache_info);
+      if (body)
+        *answer = tor_strndup(body, ri->cache_info.signed_descriptor_len);
+    } else if (! we_fetch_router_descriptors(get_options())) {
+      /* Descriptors won't be available, provide proper error */
+      *errmsg = "We fetch microdescriptors, not router "
+                "descriptors. You'll need to use md/id/* "
+                "instead of desc/id/*.";
+      return 0;
+    }
+  } else if (!strcmpstart(question, "desc/name/")) {
+    const routerinfo_t *ri = NULL;
+    /* XXX Setting 'warn_if_unnamed' here is a bit silly -- the
+     * warning goes to the user, not to the controller. */
+    const node_t *node =
+      node_get_by_nickname(question+strlen("desc/name/"), 0);
+    if (node)
+      ri = node->ri;
+    if (ri) {
+      const char *body = signed_descriptor_get_body(&ri->cache_info);
+      if (body)
+        *answer = tor_strndup(body, ri->cache_info.signed_descriptor_len);
+    } else if (! we_fetch_router_descriptors(get_options())) {
+      /* Descriptors won't be available, provide proper error */
+      *errmsg = "We fetch microdescriptors, not router "
+                "descriptors. You'll need to use md/name/* "
+                "instead of desc/name/*.";
+      return 0;
+    }
+  } else if (!strcmp(question, "desc/download-enabled")) {
+    int r = we_fetch_router_descriptors(get_options());
+    tor_asprintf(answer, "%d", !!r);
+  } else if (!strcmp(question, "desc/all-recent")) {
+    routerlist_t *routerlist = router_get_routerlist();
+    smartlist_t *sl = smartlist_new();
+    if (routerlist && routerlist->routers) {
+      SMARTLIST_FOREACH(routerlist->routers, const routerinfo_t *, ri,
+      {
+        const char *body = signed_descriptor_get_body(&ri->cache_info);
+        if (body)
+          smartlist_add(sl,
+                  tor_strndup(body, ri->cache_info.signed_descriptor_len));
+      });
+    }
+    *answer = smartlist_join_strings(sl, "", 0, NULL);
+    SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
+    smartlist_free(sl);
+  } else if (!strcmp(question, "desc/all-recent-extrainfo-hack")) {
+    /* XXXX Remove this once Torstat asks for extrainfos. */
+    routerlist_t *routerlist = router_get_routerlist();
+    smartlist_t *sl = smartlist_new();
+    if (routerlist && routerlist->routers) {
+      SMARTLIST_FOREACH_BEGIN(routerlist->routers, const routerinfo_t *, ri) {
+        const char *body = signed_descriptor_get_body(&ri->cache_info);
+        signed_descriptor_t *ei = extrainfo_get_by_descriptor_digest(
+                                     ri->cache_info.extra_info_digest);
+        if (ei && body) {
+          smartlist_add(sl, munge_extrainfo_into_routerinfo(body,
+                                                        &ri->cache_info, ei));
+        } else if (body) {
+          smartlist_add(sl,
+                  tor_strndup(body, ri->cache_info.signed_descriptor_len));
+        }
+      } SMARTLIST_FOREACH_END(ri);
+    }
+    *answer = smartlist_join_strings(sl, "", 0, NULL);
+    SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
+    smartlist_free(sl);
+  } else if (!strcmpstart(question, "hs/client/desc/id/")) {
+    hostname_type_t addr_type;
+
+    question += strlen("hs/client/desc/id/");
+    if (rend_valid_v2_service_id(question)) {
+      addr_type = ONION_V2_HOSTNAME;
+    } else if (hs_address_is_valid(question)) {
+      addr_type = ONION_V3_HOSTNAME;
+    } else {
+      *errmsg = "Invalid address";
+      return -1;
+    }
+
+    if (addr_type == ONION_V2_HOSTNAME) {
+      rend_cache_entry_t *e = NULL;
+      if (!rend_cache_lookup_entry(question, -1, &e)) {
+        /* Descriptor found in cache */
+        *answer = tor_strdup(e->desc);
+      } else {
+        *errmsg = "Not found in cache";
+        return -1;
+      }
+    } else {
+      ed25519_public_key_t service_pk;
+      const char *desc;
+
+      /* The check before this if/else makes sure of this. */
+      tor_assert(addr_type == ONION_V3_HOSTNAME);
+
+      if (hs_parse_address(question, &service_pk, NULL, NULL) < 0) {
+        *errmsg = "Invalid v3 address";
+        return -1;
+      }
+
+      desc = hs_cache_lookup_encoded_as_client(&service_pk);
+      if (desc) {
+        *answer = tor_strdup(desc);
+      } else {
+        *errmsg = "Not found in cache";
+        return -1;
+      }
+    }
+  } else if (!strcmpstart(question, "hs/service/desc/id/")) {
+    hostname_type_t addr_type;
+
+    question += strlen("hs/service/desc/id/");
+    if (rend_valid_v2_service_id(question)) {
+      addr_type = ONION_V2_HOSTNAME;
+    } else if (hs_address_is_valid(question)) {
+      addr_type = ONION_V3_HOSTNAME;
+    } else {
+      *errmsg = "Invalid address";
+      return -1;
+    }
+    rend_cache_entry_t *e = NULL;
+
+    if (addr_type == ONION_V2_HOSTNAME) {
+      if (!rend_cache_lookup_v2_desc_as_service(question, &e)) {
+        /* Descriptor found in cache */
+        *answer = tor_strdup(e->desc);
+      } else {
+        *errmsg = "Not found in cache";
+        return -1;
+      }
+    } else {
+      ed25519_public_key_t service_pk;
+      char *desc;
+
+      /* The check before this if/else makes sure of this. */
+      tor_assert(addr_type == ONION_V3_HOSTNAME);
+
+      if (hs_parse_address(question, &service_pk, NULL, NULL) < 0) {
+        *errmsg = "Invalid v3 address";
+        return -1;
+      }
+
+      desc = hs_service_lookup_current_desc(&service_pk);
+      if (desc) {
+        /* Newly allocated string, we have ownership. */
+        *answer = desc;
+      } else {
+        *errmsg = "Not found in cache";
+        return -1;
+      }
+    }
+  } else if (!strcmp(question, "md/all")) {
+    const smartlist_t *nodes = nodelist_get_list();
+    tor_assert(nodes);
+
+    if (smartlist_len(nodes) == 0) {
+      *answer = tor_strdup("");
+      return 0;
+    }
+
+    smartlist_t *microdescs = smartlist_new();
+
+    SMARTLIST_FOREACH_BEGIN(nodes, node_t *, n) {
+      if (n->md && n->md->body) {
+        char *copy = tor_strndup(n->md->body, n->md->bodylen);
+        smartlist_add(microdescs, copy);
+      }
+    } SMARTLIST_FOREACH_END(n);
+
+    *answer = smartlist_join_strings(microdescs, "", 0, NULL);
+    SMARTLIST_FOREACH(microdescs, char *, md, tor_free(md));
+    smartlist_free(microdescs);
+  } else if (!strcmpstart(question, "md/id/")) {
+    const node_t *node = node_get_by_hex_id(question+strlen("md/id/"), 0);
+    const microdesc_t *md = NULL;
+    if (node) md = node->md;
+    if (md && md->body) {
+      *answer = tor_strndup(md->body, md->bodylen);
+    }
+  } else if (!strcmpstart(question, "md/name/")) {
+    /* XXX Setting 'warn_if_unnamed' here is a bit silly -- the
+     * warning goes to the user, not to the controller. */
+    const node_t *node = node_get_by_nickname(question+strlen("md/name/"), 0);
+    /* XXXX duplicated code */
+    const microdesc_t *md = NULL;
+    if (node) md = node->md;
+    if (md && md->body) {
+      *answer = tor_strndup(md->body, md->bodylen);
+    }
+  } else if (!strcmp(question, "md/download-enabled")) {
+    int r = we_fetch_microdescriptors(get_options());
+    tor_asprintf(answer, "%d", !!r);
+  } else if (!strcmpstart(question, "desc-annotations/id/")) {
+    const routerinfo_t *ri = NULL;
+    const node_t *node =
+      node_get_by_hex_id(question+strlen("desc-annotations/id/"), 0);
+    if (node)
+      ri = node->ri;
+    if (ri) {
+      const char *annotations =
+        signed_descriptor_get_annotations(&ri->cache_info);
+      if (annotations)
+        *answer = tor_strndup(annotations,
+                              ri->cache_info.annotations_len);
+    }
+  } else if (!strcmpstart(question, "dir/server/")) {
+    size_t answer_len = 0;
+    char *url = NULL;
+    smartlist_t *descs = smartlist_new();
+    const char *msg;
+    int res;
+    char *cp;
+    tor_asprintf(&url, "/tor/%s", question+4);
+    res = dirserv_get_routerdescs(descs, url, &msg);
+    if (res) {
+      log_warn(LD_CONTROL, "getinfo '%s': %s", question, msg);
+      smartlist_free(descs);
+      tor_free(url);
+      *errmsg = msg;
+      return -1;
+    }
+    SMARTLIST_FOREACH(descs, signed_descriptor_t *, sd,
+                      answer_len += sd->signed_descriptor_len);
+    cp = *answer = tor_malloc(answer_len+1);
+    SMARTLIST_FOREACH(descs, signed_descriptor_t *, sd,
+                      {
+                        memcpy(cp, signed_descriptor_get_body(sd),
+                               sd->signed_descriptor_len);
+                        cp += sd->signed_descriptor_len;
+                      });
+    *cp = '\0';
+    tor_free(url);
+    smartlist_free(descs);
+  } else if (!strcmpstart(question, "dir/status/")) {
+    *answer = tor_strdup("");
+  } else if (!strcmp(question, "dir/status-vote/current/consensus")) { /* v3 */
+    if (we_want_to_fetch_flavor(get_options(), FLAV_NS)) {
+      const cached_dir_t *consensus = dirserv_get_consensus("ns");
+      if (consensus)
+        *answer = tor_strdup(consensus->dir);
+    }
+    if (!*answer) { /* try loading it from disk */
+      tor_mmap_t *mapped = networkstatus_map_cached_consensus("ns");
+      if (mapped) {
+        *answer = tor_memdup_nulterm(mapped->data, mapped->size);
+        tor_munmap_file(mapped);
+      }
+      if (!*answer) { /* generate an error */
+        *errmsg = "Could not open cached consensus. "
+          "Make sure FetchUselessDescriptors is set to 1.";
+        return -1;
+      }
+    }
+  } else if (!strcmp(question, "network-status")) { /* v1 */
+    static int network_status_warned = 0;
+    if (!network_status_warned) {
+      log_warn(LD_CONTROL, "GETINFO network-status is deprecated; it will "
+               "go away in a future version of Tor.");
+      network_status_warned = 1;
+    }
+    routerlist_t *routerlist = router_get_routerlist();
+    if (!routerlist || !routerlist->routers ||
+        list_server_status_v1(routerlist->routers, answer, 1) < 0) {
+      return -1;
+    }
+  } else if (!strcmpstart(question, "extra-info/digest/")) {
+    question += strlen("extra-info/digest/");
+    if (strlen(question) == HEX_DIGEST_LEN) {
+      char d[DIGEST_LEN];
+      signed_descriptor_t *sd = NULL;
+      if (base16_decode(d, sizeof(d), question, strlen(question))
+                        == sizeof(d)) {
+        /* XXXX this test should move into extrainfo_get_by_descriptor_digest,
+         * but I don't want to risk affecting other parts of the code,
+         * especially since the rules for using our own extrainfo (including
+         * when it might be freed) are different from those for using one
+         * we have downloaded. */
+        if (router_extrainfo_digest_is_me(d))
+          sd = &(router_get_my_extrainfo()->cache_info);
+        else
+          sd = extrainfo_get_by_descriptor_digest(d);
+      }
+      if (sd) {
+        const char *body = signed_descriptor_get_body(sd);
+        if (body)
+          *answer = tor_strndup(body, sd->signed_descriptor_len);
+      }
+    }
+  }
+
+  return 0;
+}
+
+/** Given a smartlist of 20-byte digests, return a newly allocated string
+ * containing each of those digests in order, formatted in HEX, and terminated
+ * with a newline. */
+static char *
+digest_list_to_string(const smartlist_t *sl)
+{
+  int len;
+  char *result, *s;
+
+  /* Allow for newlines, and a \0 at the end */
+  len = smartlist_len(sl) * (HEX_DIGEST_LEN + 1) + 1;
+  result = tor_malloc_zero(len);
+
+  s = result;
+  SMARTLIST_FOREACH_BEGIN(sl, const char *, digest) {
+    base16_encode(s, HEX_DIGEST_LEN + 1, digest, DIGEST_LEN);
+    s[HEX_DIGEST_LEN] = '\n';
+    s += HEX_DIGEST_LEN + 1;
+  } SMARTLIST_FOREACH_END(digest);
+  *s = '\0';
+
+  return result;
+}
+
+/** Turn a download_status_t into a human-readable description in a newly
+ * allocated string.  The format is specified in control-spec.txt, under
+ * the documentation for "GETINFO download/..." .  */
+static char *
+download_status_to_string(const download_status_t *dl)
+{
+  char *rv = NULL;
+  char tbuf[ISO_TIME_LEN+1];
+  const char *schedule_str, *want_authority_str;
+  const char *increment_on_str, *backoff_str;
+
+  if (dl) {
+    /* Get some substrings of the eventual output ready */
+    format_iso_time(tbuf, download_status_get_next_attempt_at(dl));
+
+    switch (dl->schedule) {
+      case DL_SCHED_GENERIC:
+        schedule_str = "DL_SCHED_GENERIC";
+        break;
+      case DL_SCHED_CONSENSUS:
+        schedule_str = "DL_SCHED_CONSENSUS";
+        break;
+      case DL_SCHED_BRIDGE:
+        schedule_str = "DL_SCHED_BRIDGE";
+        break;
+      default:
+        schedule_str = "unknown";
+        break;
+    }
+
+    switch (dl->want_authority) {
+      case DL_WANT_ANY_DIRSERVER:
+        want_authority_str = "DL_WANT_ANY_DIRSERVER";
+        break;
+      case DL_WANT_AUTHORITY:
+        want_authority_str = "DL_WANT_AUTHORITY";
+        break;
+      default:
+        want_authority_str = "unknown";
+        break;
+    }
+
+    switch (dl->increment_on) {
+      case DL_SCHED_INCREMENT_FAILURE:
+        increment_on_str = "DL_SCHED_INCREMENT_FAILURE";
+        break;
+      case DL_SCHED_INCREMENT_ATTEMPT:
+        increment_on_str = "DL_SCHED_INCREMENT_ATTEMPT";
+        break;
+      default:
+        increment_on_str = "unknown";
+        break;
+    }
+
+    backoff_str = "DL_SCHED_RANDOM_EXPONENTIAL";
+
+    /* Now assemble them */
+    tor_asprintf(&rv,
+                 "next-attempt-at %s\n"
+                 "n-download-failures %u\n"
+                 "n-download-attempts %u\n"
+                 "schedule %s\n"
+                 "want-authority %s\n"
+                 "increment-on %s\n"
+                 "backoff %s\n"
+                 "last-backoff-position %u\n"
+                 "last-delay-used %d\n",
+                 tbuf,
+                 dl->n_download_failures,
+                 dl->n_download_attempts,
+                 schedule_str,
+                 want_authority_str,
+                 increment_on_str,
+                 backoff_str,
+                 dl->last_backoff_position,
+                 dl->last_delay_used);
+  }
+
+  return rv;
+}
+
+/** Handle the consensus download cases for getinfo_helper_downloads() */
+STATIC void
+getinfo_helper_downloads_networkstatus(const char *flavor,
+                                       download_status_t **dl_to_emit,
+                                       const char **errmsg)
+{
+  /*
+   * We get the one for the current bootstrapped status by default, or
+   * take an extra /bootstrap or /running suffix
+   */
+  if (strcmp(flavor, "ns") == 0) {
+    *dl_to_emit = networkstatus_get_dl_status_by_flavor(FLAV_NS);
+  } else if (strcmp(flavor, "ns/bootstrap") == 0) {
+    *dl_to_emit = networkstatus_get_dl_status_by_flavor_bootstrap(FLAV_NS);
+  } else if (strcmp(flavor, "ns/running") == 0 ) {
+    *dl_to_emit = networkstatus_get_dl_status_by_flavor_running(FLAV_NS);
+  } else if (strcmp(flavor, "microdesc") == 0) {
+    *dl_to_emit = networkstatus_get_dl_status_by_flavor(FLAV_MICRODESC);
+  } else if (strcmp(flavor, "microdesc/bootstrap") == 0) {
+    *dl_to_emit =
+      networkstatus_get_dl_status_by_flavor_bootstrap(FLAV_MICRODESC);
+  } else if (strcmp(flavor, "microdesc/running") == 0) {
+    *dl_to_emit =
+      networkstatus_get_dl_status_by_flavor_running(FLAV_MICRODESC);
+  } else {
+    *errmsg = "Unknown flavor";
+  }
+}
+
+/** Handle the cert download cases for getinfo_helper_downloads() */
+STATIC void
+getinfo_helper_downloads_cert(const char *fp_sk_req,
+                              download_status_t **dl_to_emit,
+                              smartlist_t **digest_list,
+                              const char **errmsg)
+{
+  const char *sk_req;
+  char id_digest[DIGEST_LEN];
+  char sk_digest[DIGEST_LEN];
+
+  /*
+   * We have to handle four cases; fp_sk_req is the request with
+   * a prefix of "downloads/cert/" snipped off.
+   *
+   * Case 1: fp_sk_req = "fps"
+   *  - We should emit a digest_list with a list of all the identity
+   *    fingerprints that can be queried for certificate download status;
+   *    get it by calling list_authority_ids_with_downloads().
+   *
+   * Case 2: fp_sk_req = "fp/<fp>" for some fingerprint fp
+   *  - We want the default certificate for this identity fingerprint's
+   *    download status; this is the download we get from URLs starting
+   *    in /fp/ on the directory server.  We can get it with
+   *    id_only_download_status_for_authority_id().
+   *
+   * Case 3: fp_sk_req = "fp/<fp>/sks" for some fingerprint fp
+   *  - We want a list of all signing key digests for this identity
+   *    fingerprint which can be queried for certificate download status.
+   *    Get it with list_sk_digests_for_authority_id().
+   *
+   * Case 4: fp_sk_req = "fp/<fp>/<sk>" for some fingerprint fp and
+   *         signing key digest sk
+   *   - We want the download status for the certificate for this specific
+   *     signing key and fingerprint.  These correspond to the ones we get
+   *     from URLs starting in /fp-sk/ on the directory server.  Get it with
+   *     list_sk_digests_for_authority_id().
+   */
+
+  if (strcmp(fp_sk_req, "fps") == 0) {
+    *digest_list = list_authority_ids_with_downloads();
+    if (!(*digest_list)) {
+      *errmsg = "Failed to get list of authority identity digests (!)";
+    }
+  } else if (!strcmpstart(fp_sk_req, "fp/")) {
+    fp_sk_req += strlen("fp/");
+    /* Okay, look for another / to tell the fp from fp-sk cases */
+    sk_req = strchr(fp_sk_req, '/');
+    if (sk_req) {
+      /* okay, split it here and try to parse <fp> */
+      if (base16_decode(id_digest, DIGEST_LEN,
+                        fp_sk_req, sk_req - fp_sk_req) == DIGEST_LEN) {
+        /* Skip past the '/' */
+        ++sk_req;
+        if (strcmp(sk_req, "sks") == 0) {
+          /* We're asking for the list of signing key fingerprints */
+          *digest_list = list_sk_digests_for_authority_id(id_digest);
+          if (!(*digest_list)) {
+            *errmsg = "Failed to get list of signing key digests for this "
+                      "authority identity digest";
+          }
+        } else {
+          /* We've got a signing key digest */
+          if (base16_decode(sk_digest, DIGEST_LEN,
+                            sk_req, strlen(sk_req)) == DIGEST_LEN) {
+            *dl_to_emit =
+              download_status_for_authority_id_and_sk(id_digest, sk_digest);
+            if (!(*dl_to_emit)) {
+              *errmsg = "Failed to get download status for this identity/"
+                        "signing key digest pair";
+            }
+          } else {
+            *errmsg = "That didn't look like a signing key digest";
+          }
+        }
+      } else {
+        *errmsg = "That didn't look like an identity digest";
+      }
+    } else {
+      /* We're either in downloads/certs/fp/<fp>, or we can't parse <fp> */
+      if (strlen(fp_sk_req) == HEX_DIGEST_LEN) {
+        if (base16_decode(id_digest, DIGEST_LEN,
+                          fp_sk_req, strlen(fp_sk_req)) == DIGEST_LEN) {
+          *dl_to_emit = id_only_download_status_for_authority_id(id_digest);
+          if (!(*dl_to_emit)) {
+            *errmsg = "Failed to get download status for this authority "
+                      "identity digest";
+          }
+        } else {
+          *errmsg = "That didn't look like a digest";
+        }
+      } else {
+        *errmsg = "That didn't look like a digest";
+      }
+    }
+  } else {
+    *errmsg = "Unknown certificate download status query";
+  }
+}
+
+/** Handle the routerdesc download cases for getinfo_helper_downloads() */
+STATIC void
+getinfo_helper_downloads_desc(const char *desc_req,
+                              download_status_t **dl_to_emit,
+                              smartlist_t **digest_list,
+                              const char **errmsg)
+{
+  char desc_digest[DIGEST_LEN];
+  /*
+   * Two cases to handle here:
+   *
+   * Case 1: desc_req = "descs"
+   *   - Emit a list of all router descriptor digests, which we get by
+   *     calling router_get_descriptor_digests(); this can return NULL
+   *     if we have no current ns-flavor consensus.
+   *
+   * Case 2: desc_req = <fp>
+   *   - Check on the specified fingerprint and emit its download_status_t
+   *     using router_get_dl_status_by_descriptor_digest().
+   */
+
+  if (strcmp(desc_req, "descs") == 0) {
+    *digest_list = router_get_descriptor_digests();
+    if (!(*digest_list)) {
+      *errmsg = "We don't seem to have a networkstatus-flavored consensus";
+    }
+    /*
+     * Microdescs don't use the download_status_t mechanism, so we don't
+     * answer queries about their downloads here; see microdesc.c.
+     */
+  } else if (strlen(desc_req) == HEX_DIGEST_LEN) {
+    if (base16_decode(desc_digest, DIGEST_LEN,
+                      desc_req, strlen(desc_req)) == DIGEST_LEN) {
+      /* Okay we got a digest-shaped thing; try asking for it */
+      *dl_to_emit = router_get_dl_status_by_descriptor_digest(desc_digest);
+      if (!(*dl_to_emit)) {
+        *errmsg = "No such descriptor digest found";
+      }
+    } else {
+      *errmsg = "That didn't look like a digest";
+    }
+  } else {
+    *errmsg = "Unknown router descriptor download status query";
+  }
+}
+
+/** Handle the bridge download cases for getinfo_helper_downloads() */
+STATIC void
+getinfo_helper_downloads_bridge(const char *bridge_req,
+                                download_status_t **dl_to_emit,
+                                smartlist_t **digest_list,
+                                const char **errmsg)
+{
+  char bridge_digest[DIGEST_LEN];
+  /*
+   * Two cases to handle here:
+   *
+   * Case 1: bridge_req = "bridges"
+   *   - Emit a list of all bridge identity digests, which we get by
+   *     calling list_bridge_identities(); this can return NULL if we are
+   *     not using bridges.
+   *
+   * Case 2: bridge_req = <fp>
+   *   - Check on the specified fingerprint and emit its download_status_t
+   *     using get_bridge_dl_status_by_id().
+   */
+
+  if (strcmp(bridge_req, "bridges") == 0) {
+    *digest_list = list_bridge_identities();
+    if (!(*digest_list)) {
+      *errmsg = "We don't seem to be using bridges";
+    }
+  } else if (strlen(bridge_req) == HEX_DIGEST_LEN) {
+    if (base16_decode(bridge_digest, DIGEST_LEN,
+                      bridge_req, strlen(bridge_req)) == DIGEST_LEN) {
+      /* Okay we got a digest-shaped thing; try asking for it */
+      *dl_to_emit = get_bridge_dl_status_by_id(bridge_digest);
+      if (!(*dl_to_emit)) {
+        *errmsg = "No such bridge identity digest found";
+      }
+    } else {
+      *errmsg = "That didn't look like a digest";
+    }
+  } else {
+    *errmsg = "Unknown bridge descriptor download status query";
+  }
+}
+
+/** Implementation helper for GETINFO: knows the answers for questions about
+ * download status information. */
+STATIC int
+getinfo_helper_downloads(control_connection_t *control_conn,
+                   const char *question, char **answer,
+                   const char **errmsg)
+{
+  download_status_t *dl_to_emit = NULL;
+  smartlist_t *digest_list = NULL;
+
+  /* Assert args are sane */
+  tor_assert(control_conn != NULL);
+  tor_assert(question != NULL);
+  tor_assert(answer != NULL);
+  tor_assert(errmsg != NULL);
+
+  /* We check for this later to see if we should supply a default */
+  *errmsg = NULL;
+
+  /* Are we after networkstatus downloads? */
+  if (!strcmpstart(question, "downloads/networkstatus/")) {
+    getinfo_helper_downloads_networkstatus(
+        question + strlen("downloads/networkstatus/"),
+        &dl_to_emit, errmsg);
+  /* Certificates? */
+  } else if (!strcmpstart(question, "downloads/cert/")) {
+    getinfo_helper_downloads_cert(
+        question + strlen("downloads/cert/"),
+        &dl_to_emit, &digest_list, errmsg);
+  /* Router descriptors? */
+  } else if (!strcmpstart(question, "downloads/desc/")) {
+    getinfo_helper_downloads_desc(
+        question + strlen("downloads/desc/"),
+        &dl_to_emit, &digest_list, errmsg);
+  /* Bridge descriptors? */
+  } else if (!strcmpstart(question, "downloads/bridge/")) {
+    getinfo_helper_downloads_bridge(
+        question + strlen("downloads/bridge/"),
+        &dl_to_emit, &digest_list, errmsg);
+  } else {
+    *errmsg = "Unknown download status query";
+  }
+
+  if (dl_to_emit) {
+    *answer = download_status_to_string(dl_to_emit);
+
+    return 0;
+  } else if (digest_list) {
+    *answer = digest_list_to_string(digest_list);
+    SMARTLIST_FOREACH(digest_list, void *, s, tor_free(s));
+    smartlist_free(digest_list);
+
+    return 0;
+  } else {
+    if (!(*errmsg)) {
+      *errmsg = "Unknown error";
+    }
+
+    return -1;
+  }
+}
+
+/** Implementation helper for GETINFO: knows how to generate summaries of the
+ * current states of things we send events about. */
+static int
+getinfo_helper_events(control_connection_t *control_conn,
+                      const char *question, char **answer,
+                      const char **errmsg)
+{
+  const or_options_t *options = get_options();
+  (void) control_conn;
+  if (!strcmp(question, "circuit-status")) {
+    smartlist_t *status = smartlist_new();
+    SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ_) {
+      origin_circuit_t *circ;
+      char *circdesc;
+      const char *state;
+      if (! CIRCUIT_IS_ORIGIN(circ_) || circ_->marked_for_close)
+        continue;
+      circ = TO_ORIGIN_CIRCUIT(circ_);
+
+      if (circ->base_.state == CIRCUIT_STATE_OPEN)
+        state = "BUILT";
+      else if (circ->base_.state == CIRCUIT_STATE_GUARD_WAIT)
+        state = "GUARD_WAIT";
+      else if (circ->cpath)
+        state = "EXTENDED";
+      else
+        state = "LAUNCHED";
+
+      circdesc = circuit_describe_status_for_controller(circ);
+
+      smartlist_add_asprintf(status, "%lu %s%s%s",
+                   (unsigned long)circ->global_identifier,
+                   state, *circdesc ? " " : "", circdesc);
+      tor_free(circdesc);
+    }
+    SMARTLIST_FOREACH_END(circ_);
+    *answer = smartlist_join_strings(status, "\r\n", 0, NULL);
+    SMARTLIST_FOREACH(status, char *, cp, tor_free(cp));
+    smartlist_free(status);
+  } else if (!strcmp(question, "stream-status")) {
+    smartlist_t *conns = get_connection_array();
+    smartlist_t *status = smartlist_new();
+    char buf[256];
+    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
+      const char *state;
+      entry_connection_t *conn;
+      circuit_t *circ;
+      origin_circuit_t *origin_circ = NULL;
+      if (base_conn->type != CONN_TYPE_AP ||
+          base_conn->marked_for_close ||
+          base_conn->state == AP_CONN_STATE_SOCKS_WAIT ||
+          base_conn->state == AP_CONN_STATE_NATD_WAIT)
+        continue;
+      conn = TO_ENTRY_CONN(base_conn);
+      switch (base_conn->state)
+        {
+        case AP_CONN_STATE_CONTROLLER_WAIT:
+        case AP_CONN_STATE_CIRCUIT_WAIT:
+          if (conn->socks_request &&
+              SOCKS_COMMAND_IS_RESOLVE(conn->socks_request->command))
+            state = "NEWRESOLVE";
+          else
+            state = "NEW";
+          break;
+        case AP_CONN_STATE_RENDDESC_WAIT:
+        case AP_CONN_STATE_CONNECT_WAIT:
+          state = "SENTCONNECT"; break;
+        case AP_CONN_STATE_RESOLVE_WAIT:
+          state = "SENTRESOLVE"; break;
+        case AP_CONN_STATE_OPEN:
+          state = "SUCCEEDED"; break;
+        default:
+          log_warn(LD_BUG, "Asked for stream in unknown state %d",
+                   base_conn->state);
+          continue;
+        }
+      circ = circuit_get_by_edge_conn(ENTRY_TO_EDGE_CONN(conn));
+      if (circ && CIRCUIT_IS_ORIGIN(circ))
+        origin_circ = TO_ORIGIN_CIRCUIT(circ);
+      write_stream_target_to_buf(conn, buf, sizeof(buf));
+      smartlist_add_asprintf(status, "%lu %s %lu %s",
+                   (unsigned long) base_conn->global_identifier,state,
+                   origin_circ?
+                         (unsigned long)origin_circ->global_identifier : 0ul,
+                   buf);
+    } SMARTLIST_FOREACH_END(base_conn);
+    *answer = smartlist_join_strings(status, "\r\n", 0, NULL);
+    SMARTLIST_FOREACH(status, char *, cp, tor_free(cp));
+    smartlist_free(status);
+  } else if (!strcmp(question, "orconn-status")) {
+    smartlist_t *conns = get_connection_array();
+    smartlist_t *status = smartlist_new();
+    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
+      const char *state;
+      char name[128];
+      or_connection_t *conn;
+      if (base_conn->type != CONN_TYPE_OR || base_conn->marked_for_close)
+        continue;
+      conn = TO_OR_CONN(base_conn);
+      if (conn->base_.state == OR_CONN_STATE_OPEN)
+        state = "CONNECTED";
+      else if (conn->nickname)
+        state = "LAUNCHED";
+      else
+        state = "NEW";
+      orconn_target_get_name(name, sizeof(name), conn);
+      smartlist_add_asprintf(status, "%s %s", name, state);
+    } SMARTLIST_FOREACH_END(base_conn);
+    *answer = smartlist_join_strings(status, "\r\n", 0, NULL);
+    SMARTLIST_FOREACH(status, char *, cp, tor_free(cp));
+    smartlist_free(status);
+  } else if (!strcmpstart(question, "address-mappings/")) {
+    time_t min_e, max_e;
+    smartlist_t *mappings;
+    question += strlen("address-mappings/");
+    if (!strcmp(question, "all")) {
+      min_e = 0; max_e = TIME_MAX;
+    } else if (!strcmp(question, "cache")) {
+      min_e = 2; max_e = TIME_MAX;
+    } else if (!strcmp(question, "config")) {
+      min_e = 0; max_e = 0;
+    } else if (!strcmp(question, "control")) {
+      min_e = 1; max_e = 1;
+    } else {
+      return 0;
+    }
+    mappings = smartlist_new();
+    addressmap_get_mappings(mappings, min_e, max_e, 1);
+    *answer = smartlist_join_strings(mappings, "\r\n", 0, NULL);
+    SMARTLIST_FOREACH(mappings, char *, cp, tor_free(cp));
+    smartlist_free(mappings);
+  } else if (!strcmpstart(question, "status/")) {
+    /* Note that status/ is not a catch-all for events; there's only supposed
+     * to be a status GETINFO if there's a corresponding STATUS event. */
+    if (!strcmp(question, "status/circuit-established")) {
+      *answer = tor_strdup(have_completed_a_circuit() ? "1" : "0");
+    } else if (!strcmp(question, "status/enough-dir-info")) {
+      *answer = tor_strdup(router_have_minimum_dir_info() ? "1" : "0");
+    } else if (!strcmp(question, "status/good-server-descriptor") ||
+               !strcmp(question, "status/accepted-server-descriptor")) {
+      /* They're equivalent for now, until we can figure out how to make
+       * good-server-descriptor be what we want. See comment in
+       * control-spec.txt. */
+      *answer = tor_strdup(directories_have_accepted_server_descriptor()
+                           ? "1" : "0");
+    } else if (!strcmp(question, "status/reachability-succeeded/or")) {
+      *answer = tor_strdup(check_whether_orport_reachable(options) ?
+                            "1" : "0");
+    } else if (!strcmp(question, "status/reachability-succeeded/dir")) {
+      *answer = tor_strdup(check_whether_dirport_reachable(options) ?
+                            "1" : "0");
+    } else if (!strcmp(question, "status/reachability-succeeded")) {
+      tor_asprintf(answer, "OR=%d DIR=%d",
+                   check_whether_orport_reachable(options) ? 1 : 0,
+                   check_whether_dirport_reachable(options) ? 1 : 0);
+    } else if (!strcmp(question, "status/bootstrap-phase")) {
+      *answer = control_event_boot_last_msg();
+    } else if (!strcmpstart(question, "status/version/")) {
+      int is_server = server_mode(options);
+      networkstatus_t *c = networkstatus_get_latest_consensus();
+      version_status_t status;
+      const char *recommended;
+      if (c) {
+        recommended = is_server ? c->server_versions : c->client_versions;
+        status = tor_version_is_obsolete(VERSION, recommended);
+      } else {
+        recommended = "?";
+        status = VS_UNKNOWN;
+      }
+
+      if (!strcmp(question, "status/version/recommended")) {
+        *answer = tor_strdup(recommended);
+        return 0;
+      }
+      if (!strcmp(question, "status/version/current")) {
+        switch (status)
+          {
+          case VS_RECOMMENDED: *answer = tor_strdup("recommended"); break;
+          case VS_OLD: *answer = tor_strdup("obsolete"); break;
+          case VS_NEW: *answer = tor_strdup("new"); break;
+          case VS_NEW_IN_SERIES: *answer = tor_strdup("new in series"); break;
+          case VS_UNRECOMMENDED: *answer = tor_strdup("unrecommended"); break;
+          case VS_EMPTY: *answer = tor_strdup("none recommended"); break;
+          case VS_UNKNOWN: *answer = tor_strdup("unknown"); break;
+          default: tor_fragile_assert();
+          }
+      }
+    } else if (!strcmp(question, "status/clients-seen")) {
+      char *bridge_stats = geoip_get_bridge_stats_controller(time(NULL));
+      if (!bridge_stats) {
+        *errmsg = "No bridge-client stats available";
+        return -1;
+      }
+      *answer = bridge_stats;
+    } else if (!strcmp(question, "status/fresh-relay-descs")) {
+      if (!server_mode(options)) {
+        *errmsg = "Only relays have descriptors";
+        return -1;
+      }
+      routerinfo_t *r;
+      extrainfo_t *e;
+      if (router_build_fresh_descriptor(&r, &e) < 0) {
+        *errmsg = "Error generating descriptor";
+        return -1;
+      }
+      size_t size = r->cache_info.signed_descriptor_len + 1;
+      if (e) {
+        size += e->cache_info.signed_descriptor_len + 1;
+      }
+      tor_assert(r->cache_info.signed_descriptor_len);
+      char *descs = tor_malloc(size);
+      char *cp = descs;
+      memcpy(cp, signed_descriptor_get_body(&r->cache_info),
+             r->cache_info.signed_descriptor_len);
+      cp += r->cache_info.signed_descriptor_len - 1;
+      if (e) {
+        if (cp[0] == '\0') {
+          cp[0] = '\n';
+        } else if (cp[0] != '\n') {
+          cp[1] = '\n';
+          cp++;
+        }
+        memcpy(cp, signed_descriptor_get_body(&e->cache_info),
+               e->cache_info.signed_descriptor_len);
+        cp += e->cache_info.signed_descriptor_len - 1;
+      }
+      if (cp[0] == '\n') {
+        cp[0] = '\0';
+      } else if (cp[0] != '\0') {
+        cp[1] = '\0';
+      }
+      *answer = descs;
+      routerinfo_free(r);
+      extrainfo_free(e);
+    } else {
+      return 0;
+    }
+  }
+  return 0;
+}
+
+/** Implementation helper for GETINFO: knows how to enumerate hidden services
+ * created via the control port. */
+STATIC int
+getinfo_helper_onions(control_connection_t *control_conn,
+                      const char *question, char **answer,
+                      const char **errmsg)
+{
+  smartlist_t *onion_list = NULL;
+  (void) errmsg;  /* no errors from this method */
+
+  if (control_conn && !strcmp(question, "onions/current")) {
+    onion_list = control_conn->ephemeral_onion_services;
+  } else if (!strcmp(question, "onions/detached")) {
+    onion_list = get_detached_onion_services();
+  } else {
+    return 0;
+  }
+  if (!onion_list || smartlist_len(onion_list) == 0) {
+    if (answer) {
+      *answer = tor_strdup("");
+    }
+  } else {
+    if (answer) {
+      *answer = smartlist_join_strings(onion_list, "\r\n", 0, NULL);
+    }
+  }
+
+  return 0;
+}
+
+/** Implementation helper for GETINFO: answers queries about network
+ * liveness. */
+static int
+getinfo_helper_liveness(control_connection_t *control_conn,
+                      const char *question, char **answer,
+                      const char **errmsg)
+{
+  (void)control_conn;
+  (void)errmsg;
+  if (strcmp(question, "network-liveness") == 0) {
+    if (get_cached_network_liveness()) {
+      *answer = tor_strdup("up");
+    } else {
+      *answer = tor_strdup("down");
+    }
+  }
+
+  return 0;
+}
+
+/** Implementation helper for GETINFO: answers queries about shared random
+ * value. */
+static int
+getinfo_helper_sr(control_connection_t *control_conn,
+                  const char *question, char **answer,
+                  const char **errmsg)
+{
+  (void) control_conn;
+  (void) errmsg;
+
+  if (!strcmp(question, "sr/current")) {
+    *answer = sr_get_current_for_control();
+  } else if (!strcmp(question, "sr/previous")) {
+    *answer = sr_get_previous_for_control();
+  }
+  /* Else statement here is unrecognized key so do nothing. */
+
+  return 0;
+}
+
+/** Callback function for GETINFO: on a given control connection, try to
+ * answer the question <b>q</b> and store the newly-allocated answer in
+ * *<b>a</b>. If an internal error occurs, return -1 and optionally set
+ * *<b>error_out</b> to point to an error message to be delivered to the
+ * controller. On success, _or if the key is not recognized_, return 0. Do not
+ * set <b>a</b> if the key is not recognized but you may set <b>error_out</b>
+ * to improve the error message.
+ */
+typedef int (*getinfo_helper_t)(control_connection_t *,
+                                const char *q, char **a,
+                                const char **error_out);
+
+/** A single item for the GETINFO question-to-answer-function table. */
+typedef struct getinfo_item_t {
+  const char *varname; /**< The value (or prefix) of the question. */
+  getinfo_helper_t fn; /**< The function that knows the answer: NULL if
+                        * this entry is documentation-only. */
+  const char *desc; /**< Description of the variable. */
+  int is_prefix; /** Must varname match exactly, or must it be a prefix? */
+} getinfo_item_t;
+
+#define ITEM(name, fn, desc) { name, getinfo_helper_##fn, desc, 0 }
+#define PREFIX(name, fn, desc) { name, getinfo_helper_##fn, desc, 1 }
+#define DOC(name, desc) { name, NULL, desc, 0 }
+
+/** Table mapping questions accepted by GETINFO to the functions that know how
+ * to answer them. */
+static const getinfo_item_t getinfo_items[] = {
+  ITEM("version", misc, "The current version of Tor."),
+  ITEM("bw-event-cache", misc, "Cached BW events for a short interval."),
+  ITEM("config-file", misc, "Current location of the \"torrc\" file."),
+  ITEM("config-defaults-file", misc, "Current location of the defaults file."),
+  ITEM("config-text", misc,
+       "Return the string that would be written by a saveconf command."),
+  ITEM("config-can-saveconf", misc,
+       "Is it possible to save the configuration to the \"torrc\" file?"),
+  ITEM("accounting/bytes", accounting,
+       "Number of bytes read/written so far in the accounting interval."),
+  ITEM("accounting/bytes-left", accounting,
+      "Number of bytes left to write/read so far in the accounting interval."),
+  ITEM("accounting/enabled", accounting, "Is accounting currently enabled?"),
+  ITEM("accounting/hibernating", accounting, "Are we hibernating or awake?"),
+  ITEM("accounting/interval-start", accounting,
+       "Time when the accounting period starts."),
+  ITEM("accounting/interval-end", accounting,
+       "Time when the accounting period ends."),
+  ITEM("accounting/interval-wake", accounting,
+       "Time to wake up in this accounting period."),
+  ITEM("helper-nodes", entry_guards, NULL), /* deprecated */
+  ITEM("entry-guards", entry_guards,
+       "Which nodes are we using as entry guards?"),
+  ITEM("fingerprint", misc, NULL),
+  PREFIX("config/", config, "Current configuration values."),
+  DOC("config/names",
+      "List of configuration options, types, and documentation."),
+  DOC("config/defaults",
+      "List of default values for configuration options. "
+      "See also config/names"),
+  PREFIX("current-time/", current_time, "Current time."),
+  DOC("current-time/local", "Current time on the local system."),
+  DOC("current-time/utc", "Current UTC time."),
+  PREFIX("downloads/networkstatus/", downloads,
+         "Download statuses for networkstatus objects"),
+  DOC("downloads/networkstatus/ns",
+      "Download status for current-mode networkstatus download"),
+  DOC("downloads/networkstatus/ns/bootstrap",
+      "Download status for bootstrap-time networkstatus download"),
+  DOC("downloads/networkstatus/ns/running",
+      "Download status for run-time networkstatus download"),
+  DOC("downloads/networkstatus/microdesc",
+      "Download status for current-mode microdesc download"),
+  DOC("downloads/networkstatus/microdesc/bootstrap",
+      "Download status for bootstrap-time microdesc download"),
+  DOC("downloads/networkstatus/microdesc/running",
+      "Download status for run-time microdesc download"),
+  PREFIX("downloads/cert/", downloads,
+         "Download statuses for certificates, by id fingerprint and "
+         "signing key"),
+  DOC("downloads/cert/fps",
+      "List of authority fingerprints for which any download statuses "
+      "exist"),
+  DOC("downloads/cert/fp/<fp>",
+      "Download status for <fp> with the default signing key; corresponds "
+      "to /fp/ URLs on directory server."),
+  DOC("downloads/cert/fp/<fp>/sks",
+      "List of signing keys for which specific download statuses are "
+      "available for this id fingerprint"),
+  DOC("downloads/cert/fp/<fp>/<sk>",
+      "Download status for <fp> with signing key <sk>; corresponds "
+      "to /fp-sk/ URLs on directory server."),
+  PREFIX("downloads/desc/", downloads,
+         "Download statuses for router descriptors, by descriptor digest"),
+  DOC("downloads/desc/descs",
+      "Return a list of known router descriptor digests"),
+  DOC("downloads/desc/<desc>",
+      "Return a download status for a given descriptor digest"),
+  PREFIX("downloads/bridge/", downloads,
+         "Download statuses for bridge descriptors, by bridge identity "
+         "digest"),
+  DOC("downloads/bridge/bridges",
+      "Return a list of configured bridge identity digests with download "
+      "statuses"),
+  DOC("downloads/bridge/<desc>",
+      "Return a download status for a given bridge identity digest"),
+  ITEM("info/names", misc,
+       "List of GETINFO options, types, and documentation."),
+  ITEM("events/names", misc,
+       "Events that the controller can ask for with SETEVENTS."),
+  ITEM("signal/names", misc, "Signal names recognized by the SIGNAL command"),
+  ITEM("features/names", misc, "What arguments can USEFEATURE take?"),
+  PREFIX("desc/id/", dir, "Router descriptors by ID."),
+  PREFIX("desc/name/", dir, "Router descriptors by nickname."),
+  ITEM("desc/all-recent", dir,
+       "All non-expired, non-superseded router descriptors."),
+  ITEM("desc/download-enabled", dir,
+       "Do we try to download router descriptors?"),
+  ITEM("desc/all-recent-extrainfo-hack", dir, NULL), /* Hack. */
+  ITEM("md/all", dir, "All known microdescriptors."),
+  PREFIX("md/id/", dir, "Microdescriptors by ID"),
+  PREFIX("md/name/", dir, "Microdescriptors by name"),
+  ITEM("md/download-enabled", dir,
+       "Do we try to download microdescriptors?"),
+  PREFIX("extra-info/digest/", dir, "Extra-info documents by digest."),
+  PREFIX("hs/client/desc/id", dir,
+         "Hidden Service descriptor in client's cache by onion."),
+  PREFIX("hs/service/desc/id/", dir,
+         "Hidden Service descriptor in services's cache by onion."),
+  PREFIX("net/listeners/", listeners, "Bound addresses by type"),
+  ITEM("ns/all", networkstatus,
+       "Brief summary of router status (v2 directory format)"),
+  PREFIX("ns/id/", networkstatus,
+         "Brief summary of router status by ID (v2 directory format)."),
+  PREFIX("ns/name/", networkstatus,
+         "Brief summary of router status by nickname (v2 directory format)."),
+  PREFIX("ns/purpose/", networkstatus,
+         "Brief summary of router status by purpose (v2 directory format)."),
+  PREFIX("consensus/", networkstatus,
+         "Information about and from the ns consensus."),
+  ITEM("network-status", dir,
+       "Brief summary of router status (v1 directory format)"),
+  ITEM("network-liveness", liveness,
+       "Current opinion on whether the network is live"),
+  ITEM("circuit-status", events, "List of current circuits originating here."),
+  ITEM("stream-status", events,"List of current streams."),
+  ITEM("orconn-status", events, "A list of current OR connections."),
+  ITEM("dormant", misc,
+       "Is Tor dormant (not building circuits because it's idle)?"),
+  PREFIX("address-mappings/", events, NULL),
+  DOC("address-mappings/all", "Current address mappings."),
+  DOC("address-mappings/cache", "Current cached DNS replies."),
+  DOC("address-mappings/config",
+      "Current address mappings from configuration."),
+  DOC("address-mappings/control", "Current address mappings from controller."),
+  PREFIX("status/", events, NULL),
+  DOC("status/circuit-established",
+      "Whether we think client functionality is working."),
+  DOC("status/enough-dir-info",
+      "Whether we have enough up-to-date directory information to build "
+      "circuits."),
+  DOC("status/bootstrap-phase",
+      "The last bootstrap phase status event that Tor sent."),
+  DOC("status/clients-seen",
+      "Breakdown of client countries seen by a bridge."),
+  DOC("status/fresh-relay-descs",
+      "A fresh relay/ei descriptor pair for Tor's current state. Not stored."),
+  DOC("status/version/recommended", "List of currently recommended versions."),
+  DOC("status/version/current", "Status of the current version."),
+  ITEM("address", misc, "IP address of this Tor host, if we can guess it."),
+  ITEM("traffic/read", misc,"Bytes read since the process was started."),
+  ITEM("traffic/written", misc,
+       "Bytes written since the process was started."),
+  ITEM("uptime", misc, "Uptime of the Tor daemon in seconds."),
+  ITEM("process/pid", misc, "Process id belonging to the main tor process."),
+  ITEM("process/uid", misc, "User id running the tor process."),
+  ITEM("process/user", misc,
+       "Username under which the tor process is running."),
+  ITEM("process/descriptor-limit", misc, "File descriptor limit."),
+  ITEM("limits/max-mem-in-queues", misc, "Actual limit on memory in queues"),
+  PREFIX("desc-annotations/id/", dir, "Router annotations by hexdigest."),
+  PREFIX("dir/server/", dir,"Router descriptors as retrieved from a DirPort."),
+  PREFIX("dir/status/", dir,
+         "v2 networkstatus docs as retrieved from a DirPort."),
+  ITEM("dir/status-vote/current/consensus", dir,
+       "v3 Networkstatus consensus as retrieved from a DirPort."),
+  ITEM("exit-policy/default", policies,
+       "The default value appended to the configured exit policy."),
+  ITEM("exit-policy/reject-private/default", policies,
+       "The default rules appended to the configured exit policy by"
+       " ExitPolicyRejectPrivate."),
+  ITEM("exit-policy/reject-private/relay", policies,
+       "The relay-specific rules appended to the configured exit policy by"
+       " ExitPolicyRejectPrivate and/or ExitPolicyRejectLocalInterfaces."),
+  ITEM("exit-policy/full", policies, "The entire exit policy of onion router"),
+  ITEM("exit-policy/ipv4", policies, "IPv4 parts of exit policy"),
+  ITEM("exit-policy/ipv6", policies, "IPv6 parts of exit policy"),
+  PREFIX("ip-to-country/", geoip, "Perform a GEOIP lookup"),
+  ITEM("onions/current", onions,
+       "Onion services owned by the current control connection."),
+  ITEM("onions/detached", onions,
+       "Onion services detached from the control connection."),
+  ITEM("sr/current", sr, "Get current shared random value."),
+  ITEM("sr/previous", sr, "Get previous shared random value."),
+  { NULL, NULL, NULL, 0 }
+};
+
+/** Allocate and return a list of recognized GETINFO options. */
+static char *
+list_getinfo_options(void)
+{
+  int i;
+  smartlist_t *lines = smartlist_new();
+  char *ans;
+  for (i = 0; getinfo_items[i].varname; ++i) {
+    if (!getinfo_items[i].desc)
+      continue;
+
+    smartlist_add_asprintf(lines, "%s%s -- %s\n",
+                 getinfo_items[i].varname,
+                 getinfo_items[i].is_prefix ? "*" : "",
+                 getinfo_items[i].desc);
+  }
+  smartlist_sort_strings(lines);
+
+  ans = smartlist_join_strings(lines, "", 0, NULL);
+  SMARTLIST_FOREACH(lines, char *, cp, tor_free(cp));
+  smartlist_free(lines);
+
+  return ans;
+}
+
+/** Lookup the 'getinfo' entry <b>question</b>, and return
+ * the answer in <b>*answer</b> (or NULL if key not recognized).
+ * Return 0 if success or unrecognized, or -1 if recognized but
+ * internal error. */
+static int
+handle_getinfo_helper(control_connection_t *control_conn,
+                      const char *question, char **answer,
+                      const char **err_out)
+{
+  int i;
+  *answer = NULL; /* unrecognized key by default */
+
+  for (i = 0; getinfo_items[i].varname; ++i) {
+    int match;
+    if (getinfo_items[i].is_prefix)
+      match = !strcmpstart(question, getinfo_items[i].varname);
+    else
+      match = !strcmp(question, getinfo_items[i].varname);
+    if (match) {
+      tor_assert(getinfo_items[i].fn);
+      return getinfo_items[i].fn(control_conn, question, answer, err_out);
+    }
+  }
+
+  return 0; /* unrecognized */
+}
+
+const control_cmd_syntax_t getinfo_syntax = {
+  .max_args = UINT_MAX,
+};
+
+/** Called when we receive a GETINFO command.  Try to fetch all requested
+ * information, and reply with information or error message. */
+int
+handle_control_getinfo(control_connection_t *conn,
+                       const control_cmd_args_t *args)
+{
+  const smartlist_t *questions = args->args;
+  smartlist_t *answers = smartlist_new();
+  smartlist_t *unrecognized = smartlist_new();
+  char *ans = NULL;
+  int i;
+
+  SMARTLIST_FOREACH_BEGIN(questions, const char *, q) {
+    const char *errmsg = NULL;
+
+    if (handle_getinfo_helper(conn, q, &ans, &errmsg) < 0) {
+      if (!errmsg)
+        errmsg = "Internal error";
+      control_write_endreply(conn, 551, errmsg);
+      goto done;
+    }
+    if (!ans) {
+      if (errmsg) /* use provided error message */
+        smartlist_add_strdup(unrecognized, errmsg);
+      else /* use default error message */
+        smartlist_add_asprintf(unrecognized, "Unrecognized key \"%s\"", q);
+    } else {
+      smartlist_add_strdup(answers, q);
+      smartlist_add(answers, ans);
+    }
+  } SMARTLIST_FOREACH_END(q);
+
+  if (smartlist_len(unrecognized)) {
+    /* control-spec section 2.3, mid-reply '-' or end of reply ' ' */
+    for (i=0; i < smartlist_len(unrecognized)-1; ++i)
+      control_write_midreply(conn, 552,
+                             (char *)smartlist_get(unrecognized, i));
+
+    control_write_endreply(conn, 552, (char *)smartlist_get(unrecognized, i));
+    goto done;
+  }
+
+  for (i = 0; i < smartlist_len(answers); i += 2) {
+    char *k = smartlist_get(answers, i);
+    char *v = smartlist_get(answers, i+1);
+    if (!strchr(v, '\n') && !strchr(v, '\r')) {
+      control_printf_midreply(conn, 250, "%s=%s", k, v);
+    } else {
+      control_printf_datareply(conn, 250, "%s=", k);
+      control_write_data(conn, v);
+    }
+  }
+  send_control_done(conn);
+
+ done:
+  SMARTLIST_FOREACH(answers, char *, cp, tor_free(cp));
+  smartlist_free(answers);
+  SMARTLIST_FOREACH(unrecognized, char *, cp, tor_free(cp));
+  smartlist_free(unrecognized);
+
+  return 0;
+}
diff --git a/src/feature/control/control_getinfo.h b/src/feature/control/control_getinfo.h
new file mode 100644
index 000000000..52978686d
--- /dev/null
+++ b/src/feature/control/control_getinfo.h
@@ -0,0 +1,61 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control.h
+ * \brief Header file for control.c.
+ **/
+
+#ifndef TOR_CONTROL_GETINFO_H
+#define TOR_CONTROL_GETINFO_H
+
+struct control_cmd_syntax_t;
+struct control_cmd_args_t;
+extern const struct control_cmd_syntax_t getinfo_syntax;
+
+int handle_control_getinfo(control_connection_t *conn,
+                           const struct control_cmd_args_t *args);
+
+#ifdef CONTROL_GETINFO_PRIVATE
+STATIC int getinfo_helper_onions(
+    control_connection_t *control_conn,
+    const char *question,
+    char **answer,
+    const char **errmsg);
+STATIC void getinfo_helper_downloads_networkstatus(
+    const char *flavor,
+    download_status_t **dl_to_emit,
+    const char **errmsg);
+STATIC void getinfo_helper_downloads_cert(
+    const char *fp_sk_req,
+    download_status_t **dl_to_emit,
+    smartlist_t **digest_list,
+    const char **errmsg);
+STATIC void getinfo_helper_downloads_desc(
+    const char *desc_req,
+    download_status_t **dl_to_emit,
+    smartlist_t **digest_list,
+    const char **errmsg);
+STATIC void getinfo_helper_downloads_bridge(
+    const char *bridge_req,
+    download_status_t **dl_to_emit,
+    smartlist_t **digest_list,
+    const char **errmsg);
+STATIC int getinfo_helper_downloads(
+    control_connection_t *control_conn,
+    const char *question, char **answer,
+    const char **errmsg);
+STATIC int getinfo_helper_dir(
+    control_connection_t *control_conn,
+    const char *question, char **answer,
+    const char **errmsg);
+STATIC int getinfo_helper_current_time(
+    control_connection_t *control_conn,
+    const char *question, char **answer,
+    const char **errmsg);
+#endif /* defined(CONTROL_GETINFO_PRIVATE) */
+
+#endif /* !defined(TOR_CONTROL_GETINFO_H) */
diff --git a/src/feature/control/control_proto.c b/src/feature/control/control_proto.c
new file mode 100644
index 000000000..1dd62da2b
--- /dev/null
+++ b/src/feature/control/control_proto.c
@@ -0,0 +1,276 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_proto.c
+ * \brief Formatting functions for controller data.
+ */
+
+#include "core/or/or.h"
+
+#include "core/mainloop/connection.h"
+#include "core/or/circuitbuild.h"
+#include "core/or/circuitlist.h"
+#include "core/or/connection_edge.h"
+#include "feature/control/control_proto.h"
+#include "feature/nodelist/nodelist.h"
+
+#include "core/or/cpath_build_state_st.h"
+#include "core/or/entry_connection_st.h"
+#include "core/or/or_connection_st.h"
+#include "core/or/origin_circuit_st.h"
+#include "core/or/socks_request_st.h"
+#include "feature/control/control_connection_st.h"
+
+/** Append a NUL-terminated string <b>s</b> to the end of
+ * <b>conn</b>-\>outbuf.
+ */
+void
+connection_write_str_to_buf(const char *s, control_connection_t *conn)
+{
+  size_t len = strlen(s);
+  connection_buf_add(s, len, TO_CONN(conn));
+}
+
+/** Acts like sprintf, but writes its formatted string to the end of
+ * <b>conn</b>-\>outbuf. */
+void
+connection_printf_to_buf(control_connection_t *conn, const char *format, ...)
+{
+  va_list ap;
+  char *buf = NULL;
+  int len;
+
+  va_start(ap,format);
+  len = tor_vasprintf(&buf, format, ap);
+  va_end(ap);
+
+  if (len < 0) {
+    log_err(LD_BUG, "Unable to format string for controller.");
+    tor_assert(0);
+  }
+
+  connection_buf_add(buf, (size_t)len, TO_CONN(conn));
+
+  tor_free(buf);
+}
+
+/** Given a <b>len</b>-character string in <b>data</b>, made of lines
+ * terminated by CRLF, allocate a new string in *<b>out</b>, and copy the
+ * contents of <b>data</b> into *<b>out</b>, adding a period before any period
+ * that appears at the start of a line, and adding a period-CRLF line at
+ * the end. Replace all LF characters sequences with CRLF.  Return the number
+ * of bytes in *<b>out</b>.
+ *
+ * This corresponds to CmdData in control-spec.txt.
+ */
+size_t
+write_escaped_data(const char *data, size_t len, char **out)
+{
+  tor_assert(len < SIZE_MAX - 9);
+  size_t sz_out = len+8+1;
+  char *outp;
+  const char *start = data, *end;
+  size_t i;
+  int start_of_line;
+  for (i=0; i < len; ++i) {
+    if (data[i] == '\n') {
+      sz_out += 2; /* Maybe add a CR; maybe add a dot. */
+      if (sz_out >= SIZE_T_CEILING) {
+        log_warn(LD_BUG, "Input to write_escaped_data was too long");
+        *out = tor_strdup(".\r\n");
+        return 3;
+      }
+    }
+  }
+  *out = outp = tor_malloc(sz_out);
+  end = data+len;
+  start_of_line = 1;
+  while (data < end) {
+    if (*data == '\n') {
+      if (data > start && data[-1] != '\r')
+        *outp++ = '\r';
+      start_of_line = 1;
+    } else if (*data == '.') {
+      if (start_of_line) {
+        start_of_line = 0;
+        *outp++ = '.';
+      }
+    } else {
+      start_of_line = 0;
+    }
+    *outp++ = *data++;
+  }
+  if (outp < *out+2 || fast_memcmp(outp-2, "\r\n", 2)) {
+    *outp++ = '\r';
+    *outp++ = '\n';
+  }
+  *outp++ = '.';
+  *outp++ = '\r';
+  *outp++ = '\n';
+  *outp = '\0'; /* NUL-terminate just in case. */
+  tor_assert(outp >= *out);
+  tor_assert((size_t)(outp - *out) <= sz_out);
+  return outp - *out;
+}
+
+/** Given a <b>len</b>-character string in <b>data</b>, made of lines
+ * terminated by CRLF, allocate a new string in *<b>out</b>, and copy
+ * the contents of <b>data</b> into *<b>out</b>, removing any period
+ * that appears at the start of a line, and replacing all CRLF sequences
+ * with LF.   Return the number of
+ * bytes in *<b>out</b>.
+ *
+ * This corresponds to CmdData in control-spec.txt.
+ */
+size_t
+read_escaped_data(const char *data, size_t len, char **out)
+{
+  char *outp;
+  const char *next;
+  const char *end;
+
+  *out = outp = tor_malloc(len+1);
+
+  end = data+len;
+
+  while (data < end) {
+    /* we're at the start of a line. */
+    if (*data == '.')
+      ++data;
+    next = memchr(data, '\n', end-data);
+    if (next) {
+      size_t n_to_copy = next-data;
+      /* Don't copy a CR that precedes this LF. */
+      if (n_to_copy && *(next-1) == '\r')
+        --n_to_copy;
+      memcpy(outp, data, n_to_copy);
+      outp += n_to_copy;
+      data = next+1; /* This will point at the start of the next line,
+                      * or the end of the string, or a period. */
+    } else {
+      memcpy(outp, data, end-data);
+      outp += (end-data);
+      *outp = '\0';
+      return outp - *out;
+    }
+    *outp++ = '\n';
+  }
+
+  *outp = '\0';
+  return outp - *out;
+}
+
+/** Send a "DONE" message down the control connection <b>conn</b>. */
+void
+send_control_done(control_connection_t *conn)
+{
+  control_write_endreply(conn, 250, "OK");
+}
+
+/** Write a reply to the control channel.
+ *
+ * @param conn control connection
+ * @param code numeric result code
+ * @param c separator character, usually ' ', '-', or '+'
+ * @param s string
+ */
+void
+control_write_reply(control_connection_t *conn, int code, int c, const char *s)
+{
+  connection_printf_to_buf(conn, "%03d%c%s\r\n", code, c, s);
+}
+
+/** Write a formatted reply to the control channel.
+ *
+ * @param conn control connection
+ * @param code numeric result code
+ * @param c separator character, usually ' ', '-', or '+'
+ * @param fmt format string
+ * @param ap va_list from caller
+ */
+void
+control_vprintf_reply(control_connection_t *conn, int code, int c,
+                      const char *fmt, va_list ap)
+{
+  char *buf = NULL;
+  int len;
+
+  len = tor_vasprintf(&buf, fmt, ap);
+  if (len < 0) {
+    log_err(LD_BUG, "Unable to format string for controller.");
+    tor_assert(0);
+  }
+  control_write_reply(conn, code, c, buf);
+  tor_free(buf);
+}
+
+/** Write an EndReplyLine */
+void
+control_write_endreply(control_connection_t *conn, int code, const char *s)
+{
+  control_write_reply(conn, code, ' ', s);
+}
+
+/** Write a formatted EndReplyLine */
+void
+control_printf_endreply(control_connection_t *conn, int code,
+                        const char *fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  control_vprintf_reply(conn, code, ' ', fmt, ap);
+  va_end(ap);
+}
+
+/** Write a MidReplyLine */
+void
+control_write_midreply(control_connection_t *conn, int code, const char *s)
+{
+  control_write_reply(conn, code, '-', s);
+}
+
+/** Write a formatted MidReplyLine */
+void
+control_printf_midreply(control_connection_t *conn, int code, const char *fmt,
+                        ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  control_vprintf_reply(conn, code, '-', fmt, ap);
+  va_end(ap);
+}
+
+/** Write a DataReplyLine */
+void
+control_write_datareply(control_connection_t *conn, int code, const char *s)
+{
+  control_write_reply(conn, code, '+', s);
+}
+
+/** Write a formatted DataReplyLine */
+void
+control_printf_datareply(control_connection_t *conn, int code, const char *fmt,
+                         ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  control_vprintf_reply(conn, code, '+', fmt, ap);
+  va_end(ap);
+}
+
+/** Write a CmdData */
+void
+control_write_data(control_connection_t *conn, const char *data)
+{
+  char *esc = NULL;
+  size_t esc_len;
+
+  esc_len = write_escaped_data(data, strlen(data), &esc);
+  connection_buf_add(esc, esc_len, TO_CONN(conn));
+  tor_free(esc);
+}
diff --git a/src/feature/control/control_proto.h b/src/feature/control/control_proto.h
new file mode 100644
index 000000000..101b808d8
--- /dev/null
+++ b/src/feature/control/control_proto.h
@@ -0,0 +1,48 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file control_proto.h
+ * \brief Header file for control_proto.c.
+ **/
+
+#ifndef TOR_CONTROL_PROTO_H
+#define TOR_CONTROL_PROTO_H
+
+void connection_write_str_to_buf(const char *s, control_connection_t *conn);
+void connection_printf_to_buf(control_connection_t *conn,
+                                     const char *format, ...)
+  CHECK_PRINTF(2,3);
+
+size_t write_escaped_data(const char *data, size_t len, char **out);
+size_t read_escaped_data(const char *data, size_t len, char **out);
+void send_control_done(control_connection_t *conn);
+
+void control_write_reply(control_connection_t *conn, int code, int c,
+                         const char *s);
+void control_vprintf_reply(control_connection_t *conn, int code, int c,
+                           const char *fmt, va_list ap)
+  CHECK_PRINTF(4, 0);
+void control_write_endreply(control_connection_t *conn, int code,
+                            const char *s);
+void control_printf_endreply(control_connection_t *conn, int code,
+                             const char *fmt, ...)
+  CHECK_PRINTF(3, 4);
+void control_write_midreply(control_connection_t *conn, int code,
+                            const char *s);
+void control_printf_midreply(control_connection_t *conn, int code,
+                             const char *fmt,
+                             ...)
+  CHECK_PRINTF(3, 4);
+void control_write_datareply(control_connection_t *conn, int code,
+                             const char *s);
+void control_printf_datareply(control_connection_t *conn, int code,
+                              const char *fmt,
+                              ...)
+  CHECK_PRINTF(3, 4);
+void control_write_data(control_connection_t *conn, const char *data);
+
+#endif /* !defined(TOR_CONTROL_PROTO_H) */
diff --git a/src/feature/control/fmt_serverstatus.c b/src/feature/control/fmt_serverstatus.c
index a1ddd2119..a80bf50ad 100644
--- a/src/feature/control/fmt_serverstatus.c
+++ b/src/feature/control/fmt_serverstatus.c
@@ -66,11 +66,9 @@ list_server_status_v1(smartlist_t *routers, char **router_status_out,
   smartlist_t *rs_entries;
   time_t now = time(NULL);
   time_t cutoff = now - ROUTER_MAX_AGE_TO_PUBLISH;
-  const or_options_t *options = get_options();
   /* We include v2 dir auths here too, because they need to answer
    * controllers. Eventually we'll deprecate this whole function;
    * see also networkstatus_getinfo_by_purpose(). */
-  int authdir = authdir_mode_publishes_statuses(options);
   tor_assert(router_status_out);
 
   rs_entries = smartlist_new();
@@ -78,10 +76,6 @@ list_server_status_v1(smartlist_t *routers, char **router_status_out,
   SMARTLIST_FOREACH_BEGIN(routers, routerinfo_t *, ri) {
     const node_t *node = node_get_by_id(ri->cache_info.identity_digest);
     tor_assert(node);
-    if (authdir) {
-      /* Update router status in routerinfo_t. */
-      dirserv_set_router_is_running(ri, now);
-    }
     if (for_controller) {
       char name_buf[MAX_VERBOSE_NICKNAME_LEN+2];
       char *cp = name_buf;
diff --git a/src/feature/control/fmt_serverstatus.h b/src/feature/control/fmt_serverstatus.h
index 4b95e5b59..d9190cb7e 100644
--- a/src/feature/control/fmt_serverstatus.h
+++ b/src/feature/control/fmt_serverstatus.h
@@ -15,4 +15,4 @@
 int list_server_status_v1(smartlist_t *routers, char **router_status_out,
                           int for_controller);
 
-#endif
+#endif /* !defined(TOR_FMT_SERVERSTATUS_H) */
diff --git a/src/feature/control/getinfo_geoip.h b/src/feature/control/getinfo_geoip.h
index fe2213785..94759d0d1 100644
--- a/src/feature/control/getinfo_geoip.h
+++ b/src/feature/control/getinfo_geoip.h
@@ -11,4 +11,4 @@ int getinfo_helper_geoip(control_connection_t *control_conn,
                      const char *question, char **answer,
                      const char **errmsg);
 
-#endif
+#endif /* !defined(TOR_GETINFO_GEOIP_H) */
diff --git a/src/feature/dirauth/authmode.h b/src/feature/dirauth/authmode.h
index 876a1f947..48afc3cdb 100644
--- a/src/feature/dirauth/authmode.h
+++ b/src/feature/dirauth/authmode.h
@@ -29,7 +29,7 @@ authdir_mode_v3(const or_options_t *options)
 
 #define have_module_dirauth() (1)
 
-#else /* HAVE_MODULE_DIRAUTH */
+#else /* !(defined(HAVE_MODULE_DIRAUTH)) */
 
 #define authdir_mode(options) (((void)(options)),0)
 #define authdir_mode_handles_descs(options,purpose) \
@@ -41,6 +41,6 @@ authdir_mode_v3(const or_options_t *options)
 
 #define have_module_dirauth() (0)
 
-#endif /* HAVE_MODULE_DIRAUTH */
+#endif /* defined(HAVE_MODULE_DIRAUTH) */
 
-#endif /* TOR_MODE_H */
+#endif /* !defined(TOR_DIRAUTH_MODE_H) */
diff --git a/src/feature/dirauth/bridgeauth.c b/src/feature/dirauth/bridgeauth.c
new file mode 100644
index 000000000..4aaefc7a6
--- /dev/null
+++ b/src/feature/dirauth/bridgeauth.c
@@ -0,0 +1,55 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "core/or/or.h"
+#include "feature/dirauth/bridgeauth.h"
+#include "feature/dirauth/voteflags.h"
+#include "feature/nodelist/networkstatus.h"
+#include "feature/relay/router.h"
+#include "app/config/config.h"
+
+#include "feature/nodelist/routerinfo_st.h"
+
+/** Write out router status entries for all our bridge descriptors. Here, we
+ * also mark routers as running. */
+void
+bridgeauth_dump_bridge_status_to_file(time_t now)
+{
+  char *status;
+  char *fname = NULL;
+  char *thresholds = NULL;
+  char *published_thresholds_and_status = NULL;
+  char published[ISO_TIME_LEN+1];
+  const routerinfo_t *me = router_get_my_routerinfo();
+  char fingerprint[FINGERPRINT_LEN+1];
+  char *fingerprint_line = NULL;
+
+  dirserv_set_bridges_running(now);
+  status = networkstatus_getinfo_by_purpose("bridge", now);
+
+  if (me && crypto_pk_get_fingerprint(me->identity_pkey,
+                                      fingerprint, 0) >= 0) {
+    tor_asprintf(&fingerprint_line, "fingerprint %s\n", fingerprint);
+  } else {
+    log_warn(LD_BUG, "Error computing fingerprint for bridge status.");
+  }
+  format_iso_time(published, now);
+  dirserv_compute_bridge_flag_thresholds();
+  thresholds = dirserv_get_flag_thresholds_line();
+  tor_asprintf(&published_thresholds_and_status,
+               "published %s\nflag-thresholds %s\n%s%s",
+               published, thresholds, fingerprint_line ? fingerprint_line : "",
+               status);
+  fname = get_datadir_fname("networkstatus-bridges");
+  if (write_str_to_file(fname,published_thresholds_and_status,0)<0) {
+    log_warn(LD_DIRSERV, "Unable to write networkstatus-bridges file.");
+  }
+  tor_free(thresholds);
+  tor_free(published_thresholds_and_status);
+  tor_free(fname);
+  tor_free(status);
+  tor_free(fingerprint_line);
+}
diff --git a/src/feature/dirauth/bridgeauth.h b/src/feature/dirauth/bridgeauth.h
new file mode 100644
index 000000000..4905e9c3e
--- /dev/null
+++ b/src/feature/dirauth/bridgeauth.h
@@ -0,0 +1,12 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_DIRAUTH_BRIDGEAUTH_H
+#define TOR_DIRAUTH_BRIDGEAUTH_H
+
+void bridgeauth_dump_bridge_status_to_file(time_t now);
+
+#endif /* !defined(TOR_DIRAUTH_BRIDGEAUTH_H) */
diff --git a/src/feature/dirauth/bwauth.c b/src/feature/dirauth/bwauth.c
index 1cfd8119d..e60c8b86b 100644
--- a/src/feature/dirauth/bwauth.c
+++ b/src/feature/dirauth/bwauth.c
@@ -199,9 +199,32 @@ dirserv_get_credible_bandwidth_kb(const routerinfo_t *ri)
 }
 
 /**
- * Read the measured bandwidth list file, apply it to the list of
- * vote_routerstatus_t and store all the headers in <b>bw_file_headers</b>.
+ * Read the measured bandwidth list <b>from_file</b>:
+ * - store all the headers in <b>bw_file_headers</b>,
+ * - apply bandwidth lines to the list of vote_routerstatus_t in
+ *   <b>routerstatuses</b>,
+ * - cache bandwidth lines for dirserv_get_bandwidth_for_router(),
+ * - expire old entries in the measured bandwidth cache, and
+ * - store the DIGEST_SHA256 of the contents of the file in <b>digest_out</b>.
+ *
  * Returns -1 on error, 0 otherwise.
+ *
+ * If the file can't be read, or is empty:
+ * - <b>bw_file_headers</b> is empty,
+ * - <b>routerstatuses</b> is not modified,
+ * - the measured bandwidth cache is not modified, and
+ * - <b>digest_out</b> is the zero-byte digest.
+ *
+ * Otherwise, if there is an error later in the file:
+ * - <b>bw_file_headers</b> contains all the headers up to the error,
+ * - <b>routerstatuses</b> is updated with all the relay lines up to the error,
+ * - the measured bandwidth cache is updated with all the relay lines up to
+ *   the error,
+ * - if the timestamp is valid and recent, old entries in the  measured
+ *   bandwidth cache are expired, and
+ * - <b>digest_out</b> is the digest up to the first read error (if any).
+ *   The digest is taken over all the readable file contents, even if the
+ *   file is outdated or unparseable.
  */
 int
 dirserv_read_measured_bandwidths(const char *from_file,
@@ -223,15 +246,12 @@ dirserv_read_measured_bandwidths(const char *from_file,
   size_t n = 0;
   crypto_digest_t *digest = crypto_digest256_new(DIGEST_SHA256);
 
-  /* Initialise line, so that we can't possibly run off the end. */
-
   if (fp == NULL) {
     log_warn(LD_CONFIG, "Can't open bandwidth file at configured location: %s",
              from_file);
     goto err;
   }
 
-  /* If fgets fails, line is either unmodified, or indeterminate. */
   if (tor_getline(&line,&n,fp) <= 0) {
     log_warn(LD_DIRSERV, "Empty bandwidth file");
     goto err;
@@ -345,6 +365,9 @@ dirserv_read_measured_bandwidths(const char *from_file,
  * the header block yet. If we encounter an incomplete bw line, return -1 but
  * don't warn since there could be additional header lines coming. If we
  * encounter a proper bw line, return 0 (and we got past the headers).
+ *
+ * If the line contains "vote=0", stop parsing it, and return -1, so that the
+ * line is ignored during voting.
  */
 STATIC int
 measured_bw_line_parse(measured_bw_line_t *out, const char *orig_line,
diff --git a/src/feature/dirauth/bwauth.h b/src/feature/dirauth/bwauth.h
index 8b7acc4a1..81c8affbd 100644
--- a/src/feature/dirauth/bwauth.h
+++ b/src/feature/dirauth/bwauth.h
@@ -55,4 +55,4 @@ STATIC void dirserv_cache_measured_bw(const measured_bw_line_t *parsed_line,
 STATIC void dirserv_expire_measured_bw_cache(time_t now);
 #endif /* defined(BWAUTH_PRIVATE) */
 
-#endif
+#endif /* !defined(TOR_BWAUTH_H) */
diff --git a/src/feature/dirauth/dirauth_periodic.c b/src/feature/dirauth/dirauth_periodic.c
new file mode 100644
index 000000000..02727d61b
--- /dev/null
+++ b/src/feature/dirauth/dirauth_periodic.c
@@ -0,0 +1,161 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "core/or/or.h"
+
+#include "app/config/or_options_st.h"
+#include "core/mainloop/netstatus.h"
+#include "feature/dirauth/reachability.h"
+#include "feature/stats/rephist.h"
+
+#include "feature/dirauth/bridgeauth.h"
+#include "feature/dirauth/dirvote.h"
+#include "feature/dirauth/dirauth_periodic.h"
+#include "feature/dirauth/authmode.h"
+
+#include "core/mainloop/periodic.h"
+
+#define DECLARE_EVENT(name, roles, flags)         \
+  static periodic_event_item_t name ## _event =   \
+    PERIODIC_EVENT(name,                          \
+                   PERIODIC_EVENT_ROLE_##roles,   \
+                   flags)
+
+#define FL(name) (PERIODIC_EVENT_FLAG_##name)
+
+/**
+ * Periodic callback: if we're an authority, check on our authority
+ * certificate (the one that authenticates our authority signing key).
+ */
+static int
+check_authority_cert_callback(time_t now, const or_options_t *options)
+{
+  (void)now;
+  (void)options;
+  /* 1e. Periodically, if we're a v3 authority, we check whether our cert is
+   * close to expiring and warn the admin if it is. */
+  v3_authority_check_key_expiry();
+#define CHECK_V3_CERTIFICATE_INTERVAL (5*60)
+  return CHECK_V3_CERTIFICATE_INTERVAL;
+}
+
+DECLARE_EVENT(check_authority_cert, DIRAUTH, 0);
+
+/**
+ * Scheduled callback: Run directory-authority voting functionality.
+ *
+ * The schedule is a bit complicated here, so dirvote_act() manages the
+ * schedule itself.
+ **/
+static int
+dirvote_callback(time_t now, const or_options_t *options)
+{
+  if (!authdir_mode_v3(options)) {
+    tor_assert_nonfatal_unreached();
+    return 3600;
+  }
+
+  time_t next = dirvote_act(options, now);
+  if (BUG(next == TIME_MAX)) {
+    /* This shouldn't be returned unless we called dirvote_act() without
+     * being an authority.  If it happens, maybe our configuration will
+     * fix itself in an hour or so? */
+    return 3600;
+  }
+  return safe_timer_diff(now, next);
+}
+
+DECLARE_EVENT(dirvote, DIRAUTH, FL(NEED_NET));
+
+/** Reschedule the directory-authority voting event.  Run this whenever the
+ * schedule has changed. */
+void
+reschedule_dirvote(const or_options_t *options)
+{
+  if (authdir_mode_v3(options)) {
+    periodic_event_reschedule(&dirvote_event);
+  }
+}
+
+/**
+ * Periodic callback: if we're an authority, record our measured stability
+ * information from rephist in an mtbf file.
+ */
+static int
+save_stability_callback(time_t now, const or_options_t *options)
+{
+  if (authdir_mode_tests_reachability(options)) {
+    if (rep_hist_record_mtbf_data(now, 1)<0) {
+      log_warn(LD_GENERAL, "Couldn't store mtbf data.");
+    }
+  }
+#define SAVE_STABILITY_INTERVAL (30*60)
+  return SAVE_STABILITY_INTERVAL;
+}
+
+DECLARE_EVENT(save_stability, AUTHORITIES, 0);
+
+/**
+ * Periodic callback: if we're an authority, make sure we test
+ * the routers on the network for reachability.
+ */
+static int
+launch_reachability_tests_callback(time_t now, const or_options_t *options)
+{
+  if (authdir_mode_tests_reachability(options) &&
+      !net_is_disabled()) {
+    /* try to determine reachability of the other Tor relays */
+    dirserv_test_reachability(now);
+  }
+  return REACHABILITY_TEST_INTERVAL;
+}
+
+DECLARE_EVENT(launch_reachability_tests, AUTHORITIES, FL(NEED_NET));
+
+/**
+ * Periodic callback: if we're an authority, discount the stability
+ * information (and other rephist information) that's older.
+ */
+static int
+downrate_stability_callback(time_t now, const or_options_t *options)
+{
+  (void)options;
+  /* 1d. Periodically, we discount older stability information so that new
+   * stability info counts more, and save the stability information to disk as
+   * appropriate. */
+  time_t next = rep_hist_downrate_old_runs(now);
+  return safe_timer_diff(now, next);
+}
+
+DECLARE_EVENT(downrate_stability, AUTHORITIES, 0);
+
+/**
+ * Periodic callback: if we're the bridge authority, write a networkstatus
+ * file to disk.
+ */
+static int
+write_bridge_ns_callback(time_t now, const or_options_t *options)
+{
+  if (options->BridgeAuthoritativeDir) {
+    bridgeauth_dump_bridge_status_to_file(now);
+#define BRIDGE_STATUSFILE_INTERVAL (30*60)
+     return BRIDGE_STATUSFILE_INTERVAL;
+  }
+  return PERIODIC_EVENT_NO_UPDATE;
+}
+
+DECLARE_EVENT(write_bridge_ns, BRIDGEAUTH, 0);
+
+void
+dirauth_register_periodic_events(void)
+{
+  periodic_events_register(&downrate_stability_event);
+  periodic_events_register(&launch_reachability_tests_event);
+  periodic_events_register(&save_stability_event);
+  periodic_events_register(&check_authority_cert_event);
+  periodic_events_register(&dirvote_event);
+  periodic_events_register(&write_bridge_ns_event);
+}
diff --git a/src/feature/dirauth/dirauth_periodic.h b/src/feature/dirauth/dirauth_periodic.h
new file mode 100644
index 000000000..1124fae95
--- /dev/null
+++ b/src/feature/dirauth/dirauth_periodic.h
@@ -0,0 +1,25 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef DIRVOTE_PERIODIC_H
+#define DIRVOTE_PERIODIC_H
+
+#ifdef HAVE_MODULE_DIRAUTH
+
+void dirauth_register_periodic_events(void);
+void reschedule_dirvote(const or_options_t *options);
+
+#else /* !(defined(HAVE_MODULE_DIRAUTH)) */
+
+static inline void
+reschedule_dirvote(const or_options_t *options)
+{
+  (void)options;
+}
+
+#endif /* defined(HAVE_MODULE_DIRAUTH) */
+
+#endif /* !defined(DIRVOTE_PERIODIC_H) */
diff --git a/src/feature/dirauth/dirauth_sys.c b/src/feature/dirauth/dirauth_sys.c
new file mode 100644
index 000000000..e38d39130
--- /dev/null
+++ b/src/feature/dirauth/dirauth_sys.c
@@ -0,0 +1,40 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "core/or/or.h"
+
+#include "feature/dirauth/bwauth.h"
+#include "feature/dirauth/dirauth_sys.h"
+#include "feature/dirauth/dirvote.h"
+#include "feature/dirauth/dirauth_periodic.h"
+#include "feature/dirauth/keypin.h"
+#include "feature/dirauth/process_descs.h"
+
+#include "lib/subsys/subsys.h"
+
+static int
+subsys_dirauth_initialize(void)
+{
+  dirauth_register_periodic_events();
+  return 0;
+}
+
+static void
+subsys_dirauth_shutdown(void)
+{
+  dirserv_free_fingerprint_list();
+  dirvote_free_all();
+  dirserv_clear_measured_bw_cache();
+  keypin_close_journal();
+}
+
+const struct subsys_fns_t sys_dirauth = {
+  .name = "dirauth",
+  .supported = true,
+  .level = 70,
+  .initialize = subsys_dirauth_initialize,
+  .shutdown = subsys_dirauth_shutdown,
+};
diff --git a/src/feature/dirauth/dirauth_sys.h b/src/feature/dirauth/dirauth_sys.h
new file mode 100644
index 000000000..4e9b6a2ab
--- /dev/null
+++ b/src/feature/dirauth/dirauth_sys.h
@@ -0,0 +1,12 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef DIRAUTH_SYS_H
+#define DIRAUTH_SYS_H
+
+extern const struct subsys_fns_t sys_dirauth;
+
+#endif /* !defined(DIRAUTH_SYS_H) */
diff --git a/src/feature/dirauth/dirvote.c b/src/feature/dirauth/dirvote.c
index 755b99bae..cdbdf5a21 100644
--- a/src/feature/dirauth/dirvote.c
+++ b/src/feature/dirauth/dirvote.c
@@ -2598,7 +2598,7 @@ networkstatus_add_detached_signatures(networkstatus_t *target,
       return -1;
     }
     for (alg = DIGEST_SHA1; alg < N_COMMON_DIGEST_ALGORITHMS; ++alg) {
-      if (!tor_mem_is_zero(digests->d[alg], DIGEST256_LEN)) {
+      if (!fast_mem_is_zero(digests->d[alg], DIGEST256_LEN)) {
         if (fast_memeq(target->digests.d[alg], digests->d[alg],
                        DIGEST256_LEN)) {
           ++n_matches;
@@ -2794,7 +2794,7 @@ networkstatus_get_detached_signatures(smartlist_t *consensuses)
       char d[HEX_DIGEST256_LEN+1];
       const char *alg_name =
         crypto_digest_algorithm_get_name(alg);
-      if (tor_mem_is_zero(ns->digests.d[alg], DIGEST256_LEN))
+      if (fast_mem_is_zero(ns->digests.d[alg], DIGEST256_LEN))
         continue;
       base16_encode(d, sizeof(d), ns->digests.d[alg], DIGEST256_LEN);
       smartlist_add_asprintf(elements, "additional-digest %s %s %s\n",
@@ -3913,8 +3913,7 @@ dirvote_format_microdesc_vote_line(char *out_buf, size_t out_buf_len,
                                ",");
   tor_assert(microdesc_consensus_methods);
 
-  if (digest256_to_base64(d64, md->digest)<0)
-    goto out;
+  digest256_to_base64(d64, md->digest);
 
   if (tor_snprintf(out_buf, out_buf_len, "m %s sha256=%s\n",
                    microdesc_consensus_methods, d64)<0)
@@ -4545,8 +4544,8 @@ dirserv_generate_networkstatus_vote_obj(crypto_pk_t *private_key,
 
       vrs = tor_malloc_zero(sizeof(vote_routerstatus_t));
       rs = &vrs->status;
-      set_routerstatus_from_routerinfo(rs, node, ri, now,
-                                       listbadexits);
+      dirauth_set_routerstatus_from_routerinfo(rs, node, ri, now,
+                                               listbadexits);
 
       if (ri->cache_info.signing_key_cert) {
         memcpy(vrs->ed25519_id,
diff --git a/src/feature/dirauth/dirvote.h b/src/feature/dirauth/dirvote.h
index f9de5ebc4..a0cfe0a34 100644
--- a/src/feature/dirauth/dirvote.h
+++ b/src/feature/dirauth/dirvote.h
@@ -128,7 +128,7 @@ struct config_line_t;
 char *format_recommended_version_list(const struct config_line_t *line,
                                       int warn);
 
-#else /* HAVE_MODULE_DIRAUTH */
+#else /* !(defined(HAVE_MODULE_DIRAUTH)) */
 
 static inline time_t
 dirvote_act(const or_options_t *options, time_t now)
@@ -193,7 +193,7 @@ dirvote_add_signatures(const char *detached_signatures_body,
   return 0;
 }
 
-#endif /* HAVE_MODULE_DIRAUTH */
+#endif /* defined(HAVE_MODULE_DIRAUTH) */
 
 /* Item access */
 MOCK_DECL(const char*, dirvote_get_pending_consensus,
diff --git a/src/feature/dirauth/dsigs_parse.c b/src/feature/dirauth/dsigs_parse.c
index d88176fee..c5c8e1886 100644
--- a/src/feature/dirauth/dsigs_parse.c
+++ b/src/feature/dirauth/dsigs_parse.c
@@ -127,7 +127,7 @@ networkstatus_parse_detached_signatures(const char *s, const char *eos)
     }
     digests = detached_get_digests(sigs, flavor);
     tor_assert(digests);
-    if (!tor_mem_is_zero(digests->d[alg], digest_length)) {
+    if (!fast_mem_is_zero(digests->d[alg], digest_length)) {
       log_warn(LD_DIR, "Multiple digests for %s with %s on detached "
                "signatures document", flavor, algname);
       continue;
diff --git a/src/feature/dirauth/dsigs_parse.h b/src/feature/dirauth/dsigs_parse.h
index fec51ba48..0cc53072f 100644
--- a/src/feature/dirauth/dsigs_parse.h
+++ b/src/feature/dirauth/dsigs_parse.h
@@ -19,4 +19,4 @@ void ns_detached_signatures_free_(ns_detached_signatures_t *s);
 #define ns_detached_signatures_free(s) \
   FREE_AND_NULL(ns_detached_signatures_t, ns_detached_signatures_free_, (s))
 
-#endif
+#endif /* !defined(TOR_DSIGS_PARSE_H) */
diff --git a/src/feature/dirauth/guardfraction.h b/src/feature/dirauth/guardfraction.h
index 72404907a..9f01ded83 100644
--- a/src/feature/dirauth/guardfraction.h
+++ b/src/feature/dirauth/guardfraction.h
@@ -21,4 +21,4 @@ dirserv_read_guardfraction_file_from_str(const char *guardfraction_file_str,
 int dirserv_read_guardfraction_file(const char *fname,
                                  smartlist_t *vote_routerstatuses);
 
-#endif
+#endif /* !defined(TOR_GUARDFRACTION_H) */
diff --git a/src/feature/dirauth/ns_detached_signatures_st.h b/src/feature/dirauth/ns_detached_signatures_st.h
index 0f92be2f0..61d20b752 100644
--- a/src/feature/dirauth/ns_detached_signatures_st.h
+++ b/src/feature/dirauth/ns_detached_signatures_st.h
@@ -18,5 +18,5 @@ struct ns_detached_signatures_t {
                          * document_signature_t */
 };
 
-#endif
+#endif /* !defined(NS_DETACHED_SIGNATURES_ST_H) */
 
diff --git a/src/feature/dirauth/process_descs.h b/src/feature/dirauth/process_descs.h
index 510e54f81..001c866eb 100644
--- a/src/feature/dirauth/process_descs.h
+++ b/src/feature/dirauth/process_descs.h
@@ -36,4 +36,4 @@ void dirserv_set_node_flags_from_authoritative_status(node_t *node,
 
 int dirserv_would_reject_router(const routerstatus_t *rs);
 
-#endif
+#endif /* !defined(TOR_RECV_UPLOADS_H) */
diff --git a/src/feature/dirauth/reachability.h b/src/feature/dirauth/reachability.h
index 5a938673f..873a3f9a2 100644
--- a/src/feature/dirauth/reachability.h
+++ b/src/feature/dirauth/reachability.h
@@ -33,4 +33,4 @@ int dirserv_should_launch_reachability_test(const routerinfo_t *ri,
 void dirserv_single_reachability_test(time_t now, routerinfo_t *router);
 void dirserv_test_reachability(time_t now);
 
-#endif
+#endif /* !defined(TOR_REACHABILITY_H) */
diff --git a/src/feature/dirauth/recommend_pkg.h b/src/feature/dirauth/recommend_pkg.h
index 8200d78f7..af17e945e 100644
--- a/src/feature/dirauth/recommend_pkg.h
+++ b/src/feature/dirauth/recommend_pkg.h
@@ -12,6 +12,18 @@
 #ifndef TOR_RECOMMEND_PKG_H
 #define TOR_RECOMMEND_PKG_H
 
+#ifdef HAVE_MODULE_DIRAUTH
 int validate_recommended_package_line(const char *line);
 
-#endif
+#else
+
+static inline int
+validate_recommended_package_line(const char *line)
+{
+  (void) line;
+  return 0;
+}
+
+#endif /* defined(HAVE_MODULE_DIRAUTH) */
+
+#endif /* !defined(TOR_RECOMMEND_PKG_H) */
diff --git a/src/feature/dirauth/shared_random.c b/src/feature/dirauth/shared_random.c
index 137c49800..5ccf1a95e 100644
--- a/src/feature/dirauth/shared_random.c
+++ b/src/feature/dirauth/shared_random.c
@@ -224,7 +224,7 @@ verify_commit_and_reveal(const sr_commit_t *commit)
 STATIC int
 commit_has_reveal_value(const sr_commit_t *commit)
 {
-  return !tor_mem_is_zero(commit->encoded_reveal,
+  return !fast_mem_is_zero(commit->encoded_reveal,
                           sizeof(commit->encoded_reveal));
 }
 
@@ -486,7 +486,7 @@ get_vote_line_from_commit(const sr_commit_t *commit, sr_phase_t phase)
   {
     /* Send a reveal value for this commit if we have one. */
     const char *reveal_str = commit->encoded_reveal;
-    if (tor_mem_is_zero(commit->encoded_reveal,
+    if (fast_mem_is_zero(commit->encoded_reveal,
                         sizeof(commit->encoded_reveal))) {
       reveal_str = "";
     }
diff --git a/src/feature/dirauth/shared_random.h b/src/feature/dirauth/shared_random.h
index 0b45ad1ed..1d8fa89b0 100644
--- a/src/feature/dirauth/shared_random.h
+++ b/src/feature/dirauth/shared_random.h
@@ -110,7 +110,7 @@ int sr_init(int save_to_disk);
 void sr_save_and_cleanup(void);
 void sr_act_post_consensus(const networkstatus_t *consensus);
 
-#else /* HAVE_MODULE_DIRAUTH */
+#else /* !(defined(HAVE_MODULE_DIRAUTH)) */
 
 static inline int
 sr_init(int save_to_disk)
@@ -131,7 +131,7 @@ sr_act_post_consensus(const networkstatus_t *consensus)
   (void) consensus;
 }
 
-#endif /* HAVE_MODULE_DIRAUTH */
+#endif /* defined(HAVE_MODULE_DIRAUTH) */
 
 /* Public methods used only by dirauth code. */
 
diff --git a/src/feature/dirauth/shared_random_state.c b/src/feature/dirauth/shared_random_state.c
index a7b7480ed..b669e3836 100644
--- a/src/feature/dirauth/shared_random_state.c
+++ b/src/feature/dirauth/shared_random_state.c
@@ -538,7 +538,7 @@ disk_state_put_commit_line(const sr_commit_t *commit, config_line_t *line)
   tor_assert(commit);
   tor_assert(line);
 
-  if (!tor_mem_is_zero(commit->encoded_reveal,
+  if (!fast_mem_is_zero(commit->encoded_reveal,
                        sizeof(commit->encoded_reveal))) {
     /* Add extra whitespace so we can format the line correctly. */
     tor_asprintf(&reveal_str, " %s", commit->encoded_reveal);
@@ -937,7 +937,7 @@ state_query_del_all_(sr_state_object_t obj_type)
     } DIGESTMAP_FOREACH_END;
     break;
   }
-  /* The following object are _NOT_ suppose to be removed. */
+  /* The following objects are _NOT_ supposed to be removed. */
   case SR_STATE_OBJ_CURSRV:
   case SR_STATE_OBJ_PREVSRV:
   case SR_STATE_OBJ_PHASE:
diff --git a/src/feature/dirauth/vote_microdesc_hash_st.h b/src/feature/dirauth/vote_microdesc_hash_st.h
index 92acdf115..7869f92b4 100644
--- a/src/feature/dirauth/vote_microdesc_hash_st.h
+++ b/src/feature/dirauth/vote_microdesc_hash_st.h
@@ -18,5 +18,5 @@ struct vote_microdesc_hash_t {
   char *microdesc_hash_line;
 };
 
-#endif
+#endif /* !defined(VOTE_MICRODESC_HASH_ST_H) */
 
diff --git a/src/feature/dirauth/voteflags.c b/src/feature/dirauth/voteflags.c
index 4f7593a3e..f552af98c 100644
--- a/src/feature/dirauth/voteflags.c
+++ b/src/feature/dirauth/voteflags.c
@@ -29,6 +29,7 @@
 
 #include "feature/nodelist/node_st.h"
 #include "feature/nodelist/routerinfo_st.h"
+#include "feature/nodelist/routerlist_st.h"
 #include "feature/nodelist/vote_routerstatus_st.h"
 
 #include "lib/container/order.h"
@@ -238,7 +239,7 @@ dirserv_compute_performance_thresholds(digestmap_t *omit_as_sybil)
   uint32_t *uptimes, *bandwidths_kb, *bandwidths_excluding_exits_kb;
   long *tks;
   double *mtbfs, *wfus;
-  smartlist_t *nodelist;
+  const smartlist_t *nodelist;
   time_t now = time(NULL);
   const or_options_t *options = get_options();
 
@@ -531,38 +532,45 @@ dirserv_set_router_is_running(routerinfo_t *router, time_t now)
   node->is_running = answer;
 }
 
-/** Extract status information from <b>ri</b> and from other authority
- * functions and store it in <b>rs</b>. <b>rs</b> is zeroed out before it is
- * set.
- *
- * We assume that ri-\>is_running has already been set, e.g. by
- *   dirserv_set_router_is_running(ri, now);
+/* Check <b>node</b> and <b>ri</b> on whether or not we should publish a
+ * relay's IPv6 addresses. */
+static int
+should_publish_node_ipv6(const node_t *node, const routerinfo_t *ri,
+                         time_t now)
+{
+  const or_options_t *options = get_options();
+
+  return options->AuthDirHasIPv6Connectivity == 1 &&
+    !tor_addr_is_null(&ri->ipv6_addr) &&
+    ((node->last_reachable6 >= now - REACHABLE_TIMEOUT) ||
+     router_is_me(ri));
+}
+
+/**
+ * Extract status information from <b>ri</b> and from other authority
+ * functions and store it in <b>rs</b>, as per
+ * <b>set_routerstatus_from_routerinfo</b>.  Additionally, sets information
+ * in from the authority subsystem.
  */
 void
-set_routerstatus_from_routerinfo(routerstatus_t *rs,
-                                 node_t *node,
-                                 const routerinfo_t *ri,
-                                 time_t now,
-                                 int listbadexits)
+dirauth_set_routerstatus_from_routerinfo(routerstatus_t *rs,
+                                         node_t *node,
+                                         const routerinfo_t *ri,
+                                         time_t now,
+                                         int listbadexits)
 {
   const or_options_t *options = get_options();
   uint32_t routerbw_kb = dirserv_get_credible_bandwidth_kb(ri);
 
-  memset(rs, 0, sizeof(routerstatus_t));
-
-  rs->is_authority =
-    router_digest_is_trusted_dir(ri->cache_info.identity_digest);
-
-  /* Already set by compute_performance_thresholds. */
-  rs->is_exit = node->is_exit;
-  rs->is_stable = node->is_stable =
-    !dirserv_thinks_router_is_unreliable(now, ri, 1, 0);
-  rs->is_fast = node->is_fast =
-    !dirserv_thinks_router_is_unreliable(now, ri, 0, 1);
-  rs->is_flagged_running = node->is_running; /* computed above */
+  /* Set these flags so that set_routerstatus_from_routerinfo can copy them.
+   */
+  node->is_stable = !dirserv_thinks_router_is_unreliable(now, ri, 1, 0);
+  node->is_fast = !dirserv_thinks_router_is_unreliable(now, ri, 0, 1);
+  node->is_hs_dir = dirserv_thinks_router_is_hs_dir(ri, node, now);
 
-  rs->is_valid = node->is_valid;
+  set_routerstatus_from_routerinfo(rs, node, ri);
 
+  /* Override rs->is_possible_guard. */
   if (node->is_fast && node->is_stable &&
       ri->supports_tunnelled_dir_requests &&
       ((options->AuthDirGuardBWGuarantee &&
@@ -578,33 +586,16 @@ set_routerstatus_from_routerinfo(routerstatus_t *rs,
     rs->is_possible_guard = 0;
   }
 
+  /* Override rs->is_bad_exit */
   rs->is_bad_exit = listbadexits && node->is_bad_exit;
-  rs->is_hs_dir = node->is_hs_dir =
-    dirserv_thinks_router_is_hs_dir(ri, node, now);
-
-  rs->is_named = rs->is_unnamed = 0;
-
-  rs->published_on = ri->cache_info.published_on;
-  memcpy(rs->identity_digest, node->identity, DIGEST_LEN);
-  memcpy(rs->descriptor_digest, ri->cache_info.signed_descriptor_digest,
-         DIGEST_LEN);
-  rs->addr = ri->addr;
-  strlcpy(rs->nickname, ri->nickname, sizeof(rs->nickname));
-  rs->or_port = ri->or_port;
-  rs->dir_port = ri->dir_port;
-  rs->is_v2_dir = ri->supports_tunnelled_dir_requests;
 
+  /* Set rs->is_staledesc. */
   rs->is_staledesc =
     (ri->cache_info.published_on + DESC_IS_STALE_INTERVAL) < now;
 
-  if (options->AuthDirHasIPv6Connectivity == 1 &&
-      !tor_addr_is_null(&ri->ipv6_addr) &&
-      node->last_reachable6 >= now - REACHABLE_TIMEOUT) {
-    /* We're configured as having IPv6 connectivity. There's an IPv6
-       OR port and it's reachable so copy it to the routerstatus.  */
-    tor_addr_copy(&rs->ipv6_addr, &ri->ipv6_addr);
-    rs->ipv6_orport = ri->ipv6_orport;
-  } else {
+  if (! should_publish_node_ipv6(node, ri, now)) {
+    /* We're not configured as having IPv6 connectivity or the node isn't:
+     * zero its IPv6 information. */
     tor_addr_make_null(&rs->ipv6_addr, AF_INET6);
     rs->ipv6_orport = 0;
   }
@@ -646,3 +637,20 @@ dirserv_set_routerstatus_testing(routerstatus_t *rs)
     rs->is_hs_dir = 0;
   }
 }
+
+/** Use dirserv_set_router_is_running() to set bridges as running if they're
+ * reachable.
+ *
+ * This function is called from set_bridge_running_callback() when running as
+ * a bridge authority.
+ */
+void
+dirserv_set_bridges_running(time_t now)
+{
+  routerlist_t *rl = router_get_routerlist();
+
+  SMARTLIST_FOREACH_BEGIN(rl->routers, routerinfo_t *, ri) {
+    if (ri->purpose == ROUTER_PURPOSE_BRIDGE)
+      dirserv_set_router_is_running(ri, now);
+  } SMARTLIST_FOREACH_END(ri);
+}
diff --git a/src/feature/dirauth/voteflags.h b/src/feature/dirauth/voteflags.h
index cca6f5374..c4f36e781 100644
--- a/src/feature/dirauth/voteflags.h
+++ b/src/feature/dirauth/voteflags.h
@@ -12,24 +12,28 @@
 #ifndef TOR_VOTEFLAGS_H
 #define TOR_VOTEFLAGS_H
 
+#ifdef HAVE_MODULE_DIRAUTH
 void dirserv_set_router_is_running(routerinfo_t *router, time_t now);
 char *dirserv_get_flag_thresholds_line(void);
 void dirserv_compute_bridge_flag_thresholds(void);
 int running_long_enough_to_decide_unreachable(void);
 
-void set_routerstatus_from_routerinfo(routerstatus_t *rs,
-                                      node_t *node,
-                                      const routerinfo_t *ri,
-                                      time_t now,
-                                      int listbadexits);
+void dirauth_set_routerstatus_from_routerinfo(routerstatus_t *rs,
+                                              node_t *node,
+                                              const routerinfo_t *ri,
+                                              time_t now,
+                                              int listbadexits);
 
 void dirserv_compute_performance_thresholds(digestmap_t *omit_as_sybil);
+#endif /* defined(HAVE_MODULE_DIRAUTH) */
+
+void dirserv_set_bridges_running(time_t now);
 
 #ifdef VOTEFLAGS_PRIVATE
 /** Any descriptor older than this age causes the authorities to set the
  * StaleDesc flag. */
 #define DESC_IS_STALE_INTERVAL (18*60*60)
 STATIC void dirserv_set_routerstatus_testing(routerstatus_t *rs);
-#endif
+#endif /* defined(VOTEFLAGS_PRIVATE) */
 
-#endif
+#endif /* !defined(TOR_VOTEFLAGS_H) */
diff --git a/src/feature/dircache/cached_dir_st.h b/src/feature/dircache/cached_dir_st.h
index 71dca8c3a..a28802f90 100644
--- a/src/feature/dircache/cached_dir_st.h
+++ b/src/feature/dircache/cached_dir_st.h
@@ -21,5 +21,5 @@ struct cached_dir_t {
   int refcnt; /**< Reference count for this cached_dir_t. */
 };
 
-#endif
+#endif /* !defined(CACHED_DIR_ST_H) */
 
diff --git a/src/feature/dircache/consdiffmgr.c b/src/feature/dircache/consdiffmgr.c
index 6b16307e3..397efa034 100644
--- a/src/feature/dircache/consdiffmgr.c
+++ b/src/feature/dircache/consdiffmgr.c
@@ -525,7 +525,7 @@ consdiffmgr_add_consensus_nulterm(const char *consensus,
   tor_free(ctmp);
   return r;
 }
-#endif
+#endif /* defined(TOR_UNIT_TESTS) */
 
 /**
  * Given a buffer containing a networkstatus consensus, and the results of
diff --git a/src/feature/dircache/dircache.c b/src/feature/dircache/dircache.c
index eece1e650..1b36f716f 100644
--- a/src/feature/dircache/dircache.c
+++ b/src/feature/dircache/dircache.c
@@ -1072,13 +1072,11 @@ handle_get_status_vote(dir_connection_t *conn, const get_handler_args_t *args)
       if (compress_method != NO_METHOD) {
         conn->compress_state = tor_compress_new(1, compress_method,
                            choose_compression_level(estimated_len));
-        SMARTLIST_FOREACH(items, const char *, c,
-                 connection_buf_add_compress(c, strlen(c), conn, 0));
-        connection_buf_add_compress("", 0, conn, 1);
-      } else {
-        SMARTLIST_FOREACH(items, const char *, c,
-                         connection_buf_add(c, strlen(c), TO_CONN(conn)));
       }
+
+      SMARTLIST_FOREACH(items, const char *, c,
+                        connection_dir_buf_add(c, strlen(c), conn,
+                                               c_sl_idx == c_sl_len - 1));
     } else {
       SMARTLIST_FOREACH(dir_items, cached_dir_t *, d,
           connection_buf_add(compress_method != NO_METHOD ?
@@ -1329,19 +1327,13 @@ handle_get_keys(dir_connection_t *conn, const get_handler_args_t *args)
     if (compress_method != NO_METHOD) {
       conn->compress_state = tor_compress_new(1, compress_method,
                                               choose_compression_level(len));
-      SMARTLIST_FOREACH(certs, authority_cert_t *, c,
-            connection_buf_add_compress(
-                c->cache_info.signed_descriptor_body,
-                c->cache_info.signed_descriptor_len,
-                conn, 0));
-      connection_buf_add_compress("", 0, conn, 1);
-    } else {
-      SMARTLIST_FOREACH(certs, authority_cert_t *, c,
-            connection_buf_add(c->cache_info.signed_descriptor_body,
-                                    c->cache_info.signed_descriptor_len,
-                                    TO_CONN(conn)));
     }
-  keys_done:
+
+    SMARTLIST_FOREACH(certs, authority_cert_t *, c,
+          connection_dir_buf_add(c->cache_info.signed_descriptor_body,
+                                 c->cache_info.signed_descriptor_len,
+                                 conn, c_sl_idx == c_sl_len - 1));
+ keys_done:
     smartlist_free(certs);
     goto done;
   }
diff --git a/src/feature/dircache/dircache.h b/src/feature/dircache/dircache.h
index 236ea649e..de0d205f6 100644
--- a/src/feature/dircache/dircache.h
+++ b/src/feature/dircache/dircache.h
@@ -38,6 +38,6 @@ STATIC int parse_hs_version_from_post(const char *url, const char *prefix,
                                       const char **end_pos);
 
 STATIC unsigned parse_accept_encoding_header(const char *h);
-#endif
+#endif /* defined(DIRCACHE_PRIVATE) */
 
 #endif /* !defined(TOR_DIRCACHE_H) */
diff --git a/src/feature/dircache/dirserv.c b/src/feature/dircache/dirserv.c
index 4be6836fe..79400bf15 100644
--- a/src/feature/dircache/dirserv.c
+++ b/src/feature/dircache/dirserv.c
@@ -583,11 +583,9 @@ spooled_resource_flush_some(spooled_resource_t *spooled,
       /* Absent objects count as "done". */
       return SRFS_DONE;
     }
-    if (conn->compress_state) {
-      connection_buf_add_compress((const char*)body, bodylen, conn, 0);
-    } else {
-      connection_buf_add((const char*)body, bodylen, TO_CONN(conn));
-    }
+
+    connection_dir_buf_add((const char*)body, bodylen, conn, 0);
+
     return SRFS_DONE;
   } else {
     cached_dir_t *cached = spooled->cached_dir_ref;
@@ -622,14 +620,10 @@ spooled_resource_flush_some(spooled_resource_t *spooled,
     if (BUG(remaining < 0))
       return SRFS_ERR;
     ssize_t bytes = (ssize_t) MIN(DIRSERV_CACHED_DIR_CHUNK_SIZE, remaining);
-    if (conn->compress_state) {
-      connection_buf_add_compress(
-              ptr + spooled->cached_dir_offset,
-              bytes, conn, 0);
-    } else {
-      connection_buf_add(ptr + spooled->cached_dir_offset,
-                              bytes, TO_CONN(conn));
-    }
+
+    connection_dir_buf_add(ptr + spooled->cached_dir_offset,
+                           bytes, conn, 0);
+
     spooled->cached_dir_offset += bytes;
     if (spooled->cached_dir_offset >= (off_t)total_len) {
       return SRFS_DONE;
diff --git a/src/feature/dirclient/dir_server_st.h b/src/feature/dirclient/dir_server_st.h
index 2f5706cdd..8e3553243 100644
--- a/src/feature/dirclient/dir_server_st.h
+++ b/src/feature/dirclient/dir_server_st.h
@@ -51,4 +51,4 @@ struct dir_server_t {
                                **/
 };
 
-#endif
+#endif /* !defined(DIR_SERVER_ST_H) */
diff --git a/src/feature/dirclient/dirclient.c b/src/feature/dirclient/dirclient.c
index 70b6a2002..1ea50fd35 100644
--- a/src/feature/dirclient/dirclient.c
+++ b/src/feature/dirclient/dirclient.c
@@ -14,7 +14,7 @@
 #include "core/or/policies.h"
 #include "feature/client/bridges.h"
 #include "feature/client/entrynodes.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/authmode.h"
 #include "feature/dirauth/dirvote.h"
 #include "feature/dirauth/shared_random.h"
@@ -2531,7 +2531,7 @@ handle_response_fetch_microdesc(dir_connection_t *conn,
            conn->base_.port);
   tor_assert(conn->requested_resource &&
              !strcmpstart(conn->requested_resource, "d/"));
-  tor_assert_nonfatal(!tor_mem_is_zero(conn->identity_digest, DIGEST_LEN));
+  tor_assert_nonfatal(!fast_mem_is_zero(conn->identity_digest, DIGEST_LEN));
   which = smartlist_new();
   dir_split_resource_into_fingerprints(conn->requested_resource+2,
                                        which, NULL,
diff --git a/src/feature/dirclient/dirclient.h b/src/feature/dirclient/dirclient.h
index 1a93265dc..be4374c7c 100644
--- a/src/feature/dirclient/dirclient.h
+++ b/src/feature/dirclient/dirclient.h
@@ -167,6 +167,6 @@ STATIC int handle_response_fetch_consensus(dir_connection_t *conn,
 
 STATIC dirinfo_type_t dir_fetch_type(int dir_purpose, int router_purpose,
                                      const char *resource);
-#endif
+#endif /* defined(DIRCLIENT_PRIVATE) */
 
 #endif /* !defined(TOR_DIRCLIENT_H) */
diff --git a/src/feature/dirclient/dlstatus.h b/src/feature/dirclient/dlstatus.h
index 99e0d0225..681712b05 100644
--- a/src/feature/dirclient/dlstatus.h
+++ b/src/feature/dirclient/dlstatus.h
@@ -53,6 +53,6 @@ STATIC void next_random_exponential_delay_range(int *low_bound_out,
 /* no more than triple the previous delay */
 #define DIR_TEST_NET_RANDOM_MULTIPLIER (2)
 
-#endif
+#endif /* defined(DLSTATUS_PRIVATE) */
 
 #endif /* !defined(TOR_DLSTATUS_H) */
diff --git a/src/feature/dirclient/download_status_st.h b/src/feature/dirclient/download_status_st.h
index 11555a1dc..39a5ad286 100644
--- a/src/feature/dirclient/download_status_st.h
+++ b/src/feature/dirclient/download_status_st.h
@@ -61,5 +61,5 @@ struct download_status_t {
                         * only updated if backoff == 1 */
 };
 
-#endif
+#endif /* !defined(DOWNLOAD_STATUS_ST_H) */
 
diff --git a/src/feature/dircommon/dir_connection_st.h b/src/feature/dircommon/dir_connection_st.h
index 8c59cc7a4..a858560c2 100644
--- a/src/feature/dircommon/dir_connection_st.h
+++ b/src/feature/dircommon/dir_connection_st.h
@@ -64,4 +64,4 @@ struct dir_connection_t {
 #endif /* defined(MEASUREMENTS_21206) */
 };
 
-#endif
+#endif /* !defined(DIR_CONNECTION_ST_H) */
diff --git a/src/feature/dircommon/vote_timing_st.h b/src/feature/dircommon/vote_timing_st.h
index 47b90ab00..814a32531 100644
--- a/src/feature/dircommon/vote_timing_st.h
+++ b/src/feature/dircommon/vote_timing_st.h
@@ -20,5 +20,5 @@ struct vote_timing_t {
   int dist_delay;
 };
 
-#endif
+#endif /* !defined(VOTE_TIMING_ST_H) */
 
diff --git a/src/feature/dircommon/voting_schedule.c b/src/feature/dircommon/voting_schedule.c
index 0a7476eda..5576ec69f 100644
--- a/src/feature/dircommon/voting_schedule.c
+++ b/src/feature/dircommon/voting_schedule.c
@@ -150,7 +150,7 @@ voting_schedule_get_next_valid_after_time(void)
   /* This is a safe guard in order to make sure that the voting schedule
    * static object is at least initialized. Using this function with a zeroed
    * voting schedule can lead to bugs. */
-  if (tor_mem_is_zero((const char *) &voting_schedule,
+  if (fast_mem_is_zero((const char *) &voting_schedule,
                       sizeof(voting_schedule))) {
     need_to_recalculate_voting_schedule = true;
     goto done; /* no need for next check if we have to recalculate anyway */
diff --git a/src/feature/dircommon/voting_schedule.h b/src/feature/dircommon/voting_schedule.h
index bafd81184..d78c7ee2d 100644
--- a/src/feature/dircommon/voting_schedule.h
+++ b/src/feature/dircommon/voting_schedule.h
@@ -61,5 +61,5 @@ time_t voting_schedule_get_start_of_next_interval(time_t now,
                                                   int offset);
 time_t voting_schedule_get_next_valid_after_time(void);
 
-#endif /* TOR_VOTING_SCHEDULE_H */
+#endif /* !defined(TOR_VOTING_SCHEDULE_H) */
 
diff --git a/src/feature/dirparse/microdesc_parse.h b/src/feature/dirparse/microdesc_parse.h
index 23a90084b..95af85544 100644
--- a/src/feature/dirparse/microdesc_parse.h
+++ b/src/feature/dirparse/microdesc_parse.h
@@ -17,4 +17,4 @@ smartlist_t *microdescs_parse_from_string(const char *s, const char *eos,
                                           saved_location_t where,
                                           smartlist_t *invalid_digests_out);
 
-#endif
+#endif /* !defined(TOR_MICRODESC_PARSE_H) */
diff --git a/src/feature/dirparse/ns_parse.c b/src/feature/dirparse/ns_parse.c
index d653a5982..d5405e646 100644
--- a/src/feature/dirparse/ns_parse.c
+++ b/src/feature/dirparse/ns_parse.c
@@ -1478,7 +1478,7 @@ networkstatus_parse_vote_from_string(const char *s,
     SMARTLIST_FOREACH_BEGIN(ns->routerstatus_list, vote_routerstatus_t *,
                             vrs) {
       if (! vrs->has_ed25519_listing ||
-          tor_mem_is_zero((const char *)vrs->ed25519_id, DIGEST256_LEN))
+          fast_mem_is_zero((const char *)vrs->ed25519_id, DIGEST256_LEN))
         continue;
       if (digest256map_get(ed_id_map, vrs->ed25519_id) != NULL) {
         log_warn(LD_DIR, "Vote networkstatus ed25519 identities were not "
diff --git a/src/feature/dirparse/ns_parse.h b/src/feature/dirparse/ns_parse.h
index dedfa6fc8..0cf2cc88d 100644
--- a/src/feature/dirparse/ns_parse.h
+++ b/src/feature/dirparse/ns_parse.h
@@ -42,6 +42,6 @@ STATIC routerstatus_t *routerstatus_parse_entry_from_string(
                                      vote_routerstatus_t *vote_rs,
                                      int consensus_method,
                                      consensus_flavor_t flav);
-#endif
+#endif /* defined(NS_PARSE_PRIVATE) */
 
-#endif
+#endif /* !defined(TOR_NS_PARSE_H) */
diff --git a/src/feature/dirparse/routerparse.c b/src/feature/dirparse/routerparse.c
index ff7e15f1f..f78c46f18 100644
--- a/src/feature/dirparse/routerparse.c
+++ b/src/feature/dirparse/routerparse.c
@@ -556,6 +556,9 @@ router_parse_entry_from_string(const char *s, const char *end,
   if ((tok = find_opt_by_keyword(tokens, A_PURPOSE))) {
     tor_assert(tok->n_args);
     router->purpose = router_purpose_from_string(tok->args[0]);
+    if (router->purpose == ROUTER_PURPOSE_UNKNOWN) {
+      goto err;
+    }
   } else {
     router->purpose = ROUTER_PURPOSE_GENERAL;
   }
diff --git a/src/feature/dirparse/sigcommon.h b/src/feature/dirparse/sigcommon.h
index fdd8e839a..b6b34e8f6 100644
--- a/src/feature/dirparse/sigcommon.h
+++ b/src/feature/dirparse/sigcommon.h
@@ -43,6 +43,6 @@ MOCK_DECL(STATIC int, signed_digest_equals,
 MOCK_DECL(STATIC int, router_compute_hash_final,(char *digest,
                            const char *start, size_t len,
                            digest_algorithm_t alg));
-#endif
+#endif /* defined(SIGCOMMON_PRIVATE) */
 
 #endif /* !defined(TOR_SIGCOMMON_H) */
diff --git a/src/feature/dirparse/signing.h b/src/feature/dirparse/signing.h
index 2e3699baf..8b119b4eb 100644
--- a/src/feature/dirparse/signing.h
+++ b/src/feature/dirparse/signing.h
@@ -20,4 +20,4 @@ int router_append_dirobj_signature(char *buf, size_t buf_len,
                                    const char *digest,
                                    size_t digest_len,
                                    crypto_pk_t *private_key);
-#endif
+#endif /* !defined(TOR_SIGNING_H) */
diff --git a/src/feature/dirparse/unparseable.h b/src/feature/dirparse/unparseable.h
index 853fe8cb0..49e047961 100644
--- a/src/feature/dirparse/unparseable.h
+++ b/src/feature/dirparse/unparseable.h
@@ -51,6 +51,6 @@ EXTERN(struct smartlist_t *, descs_dumped)
 MOCK_DECL(STATIC dumped_desc_t *, dump_desc_populate_one_file,
     (const char *dirname, const char *f));
 STATIC void dump_desc_populate_fifo_from_directory(const char *dirname);
-#endif
+#endif /* defined(UNPARSEABLE_PRIVATE) */
 
 #endif /* !defined(TOR_UNPARSEABLE_H) */
diff --git a/src/feature/hibernate/hibernate.c b/src/feature/hibernate/hibernate.c
index 70c2b4f69..674fe3c81 100644
--- a/src/feature/hibernate/hibernate.c
+++ b/src/feature/hibernate/hibernate.c
@@ -35,7 +35,7 @@ hibernating, phase 2:
 #include "core/mainloop/connection.h"
 #include "core/or/connection_edge.h"
 #include "core/or/connection_or.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/defs/time.h"
 #include "feature/hibernate/hibernate.h"
@@ -57,7 +57,7 @@ hibernating, phase 2:
  * Coverity. Here's a kludge to unconfuse it.
  */
 #   define __INCLUDE_LEVEL__ 2
-# endif /* defined(__COVERITY__) && !defined(__INCLUDE_LEVEL__) */
+#endif /* defined(__COVERITY__) && !defined(__INCLUDE_LEVEL__) */
 #include <systemd/sd-daemon.h>
 #endif /* defined(HAVE_SYSTEMD) */
 
@@ -893,7 +893,7 @@ hibernate_begin(hibernate_state_t new_state, time_t now)
      */
     sd_notifyf(0, "EXTEND_TIMEOUT_USEC=%" PRIu64,
             ((uint64_t)(options->ShutdownWaitLength) + 30) * TOR_USEC_PER_SEC);
-#endif
+#endif /* defined(HAVE_SYSTEMD) */
   } else { /* soft limit reached */
     hibernate_end_time = interval_end_time;
   }
diff --git a/src/feature/hibernate/hibernate.h b/src/feature/hibernate/hibernate.h
index 3309ef0ce..2e245f6ab 100644
--- a/src/feature/hibernate/hibernate.h
+++ b/src/feature/hibernate/hibernate.h
@@ -32,6 +32,7 @@ int getinfo_helper_accounting(control_connection_t *conn,
                               const char **errmsg);
 uint64_t get_accounting_max_total(void);
 void accounting_free_all(void);
+bool accounting_tor_is_dormant(void);
 
 #ifdef HIBERNATE_PRIVATE
 /** Possible values of hibernate_state */
diff --git a/src/feature/hs/hs_cell.c b/src/feature/hs/hs_cell.c
index 613ffe726..69f1ccbef 100644
--- a/src/feature/hs/hs_cell.c
+++ b/src/feature/hs/hs_cell.c
@@ -758,7 +758,14 @@ hs_cell_parse_introduce2(hs_cell_introduce2_data_t *data,
        idx < trn_cell_introduce_encrypted_get_nspec(enc_cell); idx++) {
     link_specifier_t *lspec =
       trn_cell_introduce_encrypted_get_nspecs(enc_cell, idx);
-    smartlist_add(data->link_specifiers, hs_link_specifier_dup(lspec));
+    if (BUG(!lspec)) {
+      goto done;
+    }
+    link_specifier_t *lspec_dup = link_specifier_dup(lspec);
+    if (BUG(!lspec_dup)) {
+      goto done;
+    }
+    smartlist_add(data->link_specifiers, lspec_dup);
   }
 
   /* Success. */
diff --git a/src/feature/hs/hs_circuit.c b/src/feature/hs/hs_circuit.c
index e3873d2f1..716c4b1f1 100644
--- a/src/feature/hs/hs_circuit.c
+++ b/src/feature/hs/hs_circuit.c
@@ -15,6 +15,7 @@
 #include "core/or/circuituse.h"
 #include "core/or/policies.h"
 #include "core/or/relay.h"
+#include "core/or/crypt_path.h"
 #include "feature/client/circpathbias.h"
 #include "feature/hs/hs_cell.h"
 #include "feature/hs/hs_circuit.h"
@@ -89,7 +90,7 @@ create_rend_cpath(const uint8_t *ntor_key_seed, size_t seed_len,
   cpath = tor_malloc_zero(sizeof(crypt_path_t));
   cpath->magic = CRYPT_PATH_MAGIC;
 
-  if (circuit_init_cpath_crypto(cpath, (char*)keys, sizeof(keys),
+  if (cpath_init_circuit_crypto(cpath, (char*)keys, sizeof(keys),
                                 is_service_side, 1) < 0) {
     tor_free(cpath);
     goto err;
@@ -126,7 +127,7 @@ create_rend_cpath_legacy(origin_circuit_t *circ, const uint8_t *rend_cell_body)
     goto err;
   }
   /* ... and set up cpath. */
-  if (circuit_init_cpath_crypto(hop,
+  if (cpath_init_circuit_crypto(hop,
                                 keys+DIGEST_LEN, sizeof(keys)-DIGEST_LEN,
                                 0, 0) < 0)
     goto err;
@@ -177,7 +178,7 @@ finalize_rend_circuit(origin_circuit_t *circ, crypt_path_t *hop,
   circ->hs_circ_has_timed_out = 0;
 
   /* Append the hop to the cpath of this circuit */
-  onion_append_to_cpath(&circ->cpath, hop);
+  cpath_extend_linked_list(&circ->cpath, hop);
 
   /* In legacy code, 'pending_final_cpath' points to the final hop we just
    * appended to the cpath. We set the original pointer to NULL so that we
@@ -405,8 +406,12 @@ launch_rendezvous_point_circuit(const hs_service_t *service,
     if (circ_needs_uptime) {
       circ_flags |= CIRCLAUNCH_NEED_UPTIME;
     }
-    /* Firewall and policies are checked when getting the extend info. */
-    if (service->config.is_single_onion) {
+    /* Firewall and policies are checked when getting the extend info.
+     *
+     * We only use a one-hop path on the first attempt. If the first attempt
+     * fails, we use a 3-hop path for reachability / reliability.
+     * See the comment in retry_service_rendezvous_point() for details. */
+    if (service->config.is_single_onion && i == 0) {
       circ_flags |= CIRCLAUNCH_ONEHOP_TUNNEL;
     }
 
@@ -565,81 +570,6 @@ retry_service_rendezvous_point(const origin_circuit_t *circ)
   return;
 }
 
-/* Add all possible link specifiers in node to lspecs:
- *  - legacy ID is mandatory thus MUST be present in node;
- *  - include ed25519 link specifier if present in the node, and the node
- *    supports ed25519 link authentication, even if its link versions are not
- *    compatible with us;
- *  - include IPv4 link specifier, if the primary address is not IPv4, log a
- *    BUG() warning, and return an empty smartlist;
- *  - include IPv6 link specifier if present in the node. */
-static void
-get_lspecs_from_node(const node_t *node, smartlist_t *lspecs)
-{
-  link_specifier_t *ls;
-  tor_addr_port_t ap;
-
-  tor_assert(node);
-  tor_assert(lspecs);
-
-  /* Get the relay's IPv4 address. */
-  node_get_prim_orport(node, &ap);
-
-  /* We expect the node's primary address to be a valid IPv4 address.
-   * This conforms to the protocol, which requires either an IPv4 or IPv6
-   * address (or both). */
-  if (BUG(!tor_addr_is_v4(&ap.addr)) ||
-      BUG(!tor_addr_port_is_valid_ap(&ap, 0))) {
-    return;
-  }
-
-  ls = link_specifier_new();
-  link_specifier_set_ls_type(ls, LS_IPV4);
-  link_specifier_set_un_ipv4_addr(ls, tor_addr_to_ipv4h(&ap.addr));
-  link_specifier_set_un_ipv4_port(ls, ap.port);
-  /* Four bytes IPv4 and two bytes port. */
-  link_specifier_set_ls_len(ls, sizeof(ap.addr.addr.in_addr) +
-                            sizeof(ap.port));
-  smartlist_add(lspecs, ls);
-
-  /* Legacy ID is mandatory and will always be present in node. */
-  ls = link_specifier_new();
-  link_specifier_set_ls_type(ls, LS_LEGACY_ID);
-  memcpy(link_specifier_getarray_un_legacy_id(ls), node->identity,
-         link_specifier_getlen_un_legacy_id(ls));
-  link_specifier_set_ls_len(ls, link_specifier_getlen_un_legacy_id(ls));
-  smartlist_add(lspecs, ls);
-
-  /* ed25519 ID is only included if the node has it, and the node declares a
-     protocol version that supports ed25519 link authentication, even if that
-     link version is not compatible with us. (We are sending the ed25519 key
-     to another tor, which may support different link versions.) */
-  if (!ed25519_public_key_is_zero(&node->ed25519_id) &&
-      node_supports_ed25519_link_authentication(node, 0)) {
-    ls = link_specifier_new();
-    link_specifier_set_ls_type(ls, LS_ED25519_ID);
-    memcpy(link_specifier_getarray_un_ed25519_id(ls), &node->ed25519_id,
-           link_specifier_getlen_un_ed25519_id(ls));
-    link_specifier_set_ls_len(ls, link_specifier_getlen_un_ed25519_id(ls));
-    smartlist_add(lspecs, ls);
-  }
-
-  /* Check for IPv6. If so, include it as well. */
-  if (node_has_ipv6_orport(node)) {
-    ls = link_specifier_new();
-    node_get_pref_ipv6_orport(node, &ap);
-    link_specifier_set_ls_type(ls, LS_IPV6);
-    size_t addr_len = link_specifier_getlen_un_ipv6_addr(ls);
-    const uint8_t *in6_addr = tor_addr_to_in6_addr8(&ap.addr);
-    uint8_t *ipv6_array = link_specifier_getarray_un_ipv6_addr(ls);
-    memcpy(ipv6_array, in6_addr, addr_len);
-    link_specifier_set_un_ipv6_port(ls, ap.port);
-    /* Sixteen bytes IPv6 and two bytes port. */
-    link_specifier_set_ls_len(ls, addr_len + sizeof(ap.port));
-    smartlist_add(lspecs, ls);
-  }
-}
-
 /* Using the given descriptor intro point ip, the node of the
  * rendezvous point rp_node and the service's subcredential, populate the
  * already allocated intro1_data object with the needed key material and link
@@ -662,10 +592,9 @@ setup_introduce1_data(const hs_desc_intro_point_t *ip,
   tor_assert(subcredential);
   tor_assert(intro1_data);
 
-  /* Build the link specifiers from the extend information of the rendezvous
-   * circuit that we've picked previously. */
-  rp_lspecs = smartlist_new();
-  get_lspecs_from_node(rp_node, rp_lspecs);
+  /* Build the link specifiers from the node at the end of the rendezvous
+   * circuit that we opened for this introduction. */
+  rp_lspecs = node_get_link_specifier_smartlist(rp_node, 0);
   if (smartlist_len(rp_lspecs) == 0) {
     /* We can't rendezvous without link specifiers. */
     smartlist_free(rp_lspecs);
@@ -754,13 +683,16 @@ hs_circ_retry_service_rendezvous_point(origin_circuit_t *circ)
 }
 
 /* For a given service and a service intro point, launch a circuit to the
- * extend info ei. If the service is a single onion, a one-hop circuit will be
- * requested. Return 0 if the circuit was successfully launched and tagged
+ * extend info ei. If the service is a single onion, and direct_conn is true,
+ * a one-hop circuit will be requested.
+ *
+ * Return 0 if the circuit was successfully launched and tagged
  * with the correct identifier. On error, a negative value is returned. */
 int
 hs_circ_launch_intro_point(hs_service_t *service,
                            const hs_service_intro_point_t *ip,
-                           extend_info_t *ei)
+                           extend_info_t *ei,
+                           bool direct_conn)
 {
   /* Standard flags for introduction circuit. */
   int ret = -1, circ_flags = CIRCLAUNCH_NEED_UPTIME | CIRCLAUNCH_IS_INTERNAL;
@@ -772,7 +704,16 @@ hs_circ_launch_intro_point(hs_service_t *service,
 
   /* Update circuit flags in case of a single onion service that requires a
    * direct connection. */
-  if (service->config.is_single_onion) {
+  tor_assert_nonfatal(ip->circuit_retries > 0);
+  /* Only single onion services can make direct conns */
+  if (BUG(!service->config.is_single_onion && direct_conn)) {
+    goto end;
+  }
+  /* We only use a one-hop path on the first attempt. If the first attempt
+   * fails, we use a 3-hop path for reachability / reliability.
+   * (Unlike v2, retries is incremented by the caller before it calls this
+   * function.) */
+  if (direct_conn && ip->circuit_retries == 1) {
     circ_flags |= CIRCLAUNCH_ONEHOP_TUNNEL;
   }
 
@@ -1044,9 +985,7 @@ hs_circ_handle_introduce2(const hs_service_t *service,
   ret = 0;
 
  done:
-  SMARTLIST_FOREACH(data.link_specifiers, link_specifier_t *, lspec,
-                    link_specifier_free(lspec));
-  smartlist_free(data.link_specifiers);
+  link_specifier_smartlist_free(data.link_specifiers);
   memwipe(&data, 0, sizeof(data));
   return ret;
 }
diff --git a/src/feature/hs/hs_circuit.h b/src/feature/hs/hs_circuit.h
index b8d8b25ad..e168b301f 100644
--- a/src/feature/hs/hs_circuit.h
+++ b/src/feature/hs/hs_circuit.h
@@ -26,7 +26,8 @@ void hs_circ_service_rp_has_opened(const hs_service_t *service,
                                    origin_circuit_t *circ);
 int hs_circ_launch_intro_point(hs_service_t *service,
                                const hs_service_intro_point_t *ip,
-                               extend_info_t *ei);
+                               extend_info_t *ei,
+                               bool direct_conn);
 int hs_circ_launch_rendezvous_point(const hs_service_t *service,
                                     const curve25519_public_key_t *onion_key,
                                     const uint8_t *rendezvous_cookie);
diff --git a/src/feature/hs/hs_client.c b/src/feature/hs/hs_client.c
index 2a5765aec..f8d47f011 100644
--- a/src/feature/hs/hs_client.c
+++ b/src/feature/hs/hs_client.c
@@ -167,9 +167,7 @@ purge_hid_serv_request(const ed25519_public_key_t *identity_pk)
    * some point and we don't care about those anymore. */
   hs_build_blinded_pubkey(identity_pk, NULL, 0,
                           hs_get_time_period_num(0), &blinded_pk);
-  if (BUG(ed25519_public_to_base64(base64_blinded_pk, &blinded_pk) < 0)) {
-    return;
-  }
+  ed25519_public_to_base64(base64_blinded_pk, &blinded_pk);
   /* Purge last hidden service request from cache for this blinded key. */
   hs_purge_hid_serv_from_last_hid_serv_requests(base64_blinded_pk);
 }
@@ -356,7 +354,6 @@ directory_launch_v3_desc_fetch(const ed25519_public_key_t *onion_identity_pk,
   ed25519_public_key_t blinded_pubkey;
   char base64_blinded_pubkey[ED25519_BASE64_LEN + 1];
   hs_ident_dir_conn_t hs_conn_dir_ident;
-  int retval;
 
   tor_assert(hsdir);
   tor_assert(onion_identity_pk);
@@ -365,10 +362,7 @@ directory_launch_v3_desc_fetch(const ed25519_public_key_t *onion_identity_pk,
   hs_build_blinded_pubkey(onion_identity_pk, NULL, 0,
                           current_time_period, &blinded_pubkey);
   /* ...and base64 it. */
-  retval = ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
-  if (BUG(retval < 0)) {
-    return HS_CLIENT_FETCH_ERROR;
-  }
+  ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
 
   /* Copy onion pk to a dir_ident so that we attach it to the dir conn */
   hs_ident_dir_conn_init(onion_identity_pk, &blinded_pubkey,
@@ -407,7 +401,6 @@ directory_launch_v3_desc_fetch(const ed25519_public_key_t *onion_identity_pk,
 STATIC routerstatus_t *
 pick_hsdir_v3(const ed25519_public_key_t *onion_identity_pk)
 {
-  int retval;
   char base64_blinded_pubkey[ED25519_BASE64_LEN + 1];
   uint64_t current_time_period = hs_get_time_period_num(0);
   smartlist_t *responsible_hsdirs = NULL;
@@ -420,10 +413,7 @@ pick_hsdir_v3(const ed25519_public_key_t *onion_identity_pk)
   hs_build_blinded_pubkey(onion_identity_pk, NULL, 0,
                           current_time_period, &blinded_pubkey);
   /* ...and base64 it. */
-  retval = ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
-  if (BUG(retval < 0)) {
-    return NULL;
-  }
+  ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
 
   /* Get responsible hsdirs of service for this time period */
   responsible_hsdirs = smartlist_new();
@@ -436,7 +426,7 @@ pick_hsdir_v3(const ed25519_public_key_t *onion_identity_pk)
 
   /* Pick an HSDir from the responsible ones. The ownership of
    * responsible_hsdirs is given to this function so no need to free it. */
-  hsdir_rs = hs_pick_hsdir(responsible_hsdirs, base64_blinded_pubkey);
+  hsdir_rs = hs_pick_hsdir(responsible_hsdirs, base64_blinded_pubkey, NULL);
 
   return hsdir_rs;
 }
@@ -461,6 +451,24 @@ fetch_v3_desc, (const ed25519_public_key_t *onion_identity_pk))
   return directory_launch_v3_desc_fetch(onion_identity_pk, hsdir_rs);
 }
 
+/* With a given <b>onion_identity_pk</b>, fetch its descriptor. If
+ * <b>hsdirs</b> is specified, use the directory servers specified in the list.
+ * Else, use a random server. */
+void
+hs_client_launch_v3_desc_fetch(const ed25519_public_key_t *onion_identity_pk,
+                               const smartlist_t *hsdirs)
+{
+  tor_assert(onion_identity_pk);
+
+  if (hsdirs != NULL) {
+    SMARTLIST_FOREACH_BEGIN(hsdirs, const routerstatus_t *, hsdir) {
+      directory_launch_v3_desc_fetch(onion_identity_pk, hsdir);
+    } SMARTLIST_FOREACH_END(hsdir);
+  } else {
+    fetch_v3_desc(onion_identity_pk);
+  }
+}
+
 /* Make sure that the given v3 origin circuit circ is a valid correct
  * introduction circuit. This will BUG() on any problems and hard assert if
  * the anonymity of the circuit is not ok. Return 0 on success else -1 where
@@ -530,13 +538,15 @@ find_desc_intro_point_by_legacy_id(const char *legacy_id,
   SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
                           hs_desc_intro_point_t *, ip) {
     SMARTLIST_FOREACH_BEGIN(ip->link_specifiers,
-                            const hs_desc_link_specifier_t *, lspec) {
+                            const link_specifier_t *, lspec) {
       /* Not all tor node have an ed25519 identity key so we still rely on the
        * legacy identity digest. */
-      if (lspec->type != LS_LEGACY_ID) {
+      if (link_specifier_get_ls_type(lspec) != LS_LEGACY_ID) {
         continue;
       }
-      if (fast_memneq(legacy_id, lspec->u.legacy_id, DIGEST_LEN)) {
+      if (fast_memneq(legacy_id,
+                      link_specifier_getconstarray_un_legacy_id(lspec),
+                      DIGEST_LEN)) {
         break;
       }
       /* Found it. */
@@ -689,7 +699,7 @@ setup_intro_circ_auth_key(origin_circuit_t *circ)
   }
 
   /* Reaching this point means we didn't find any intro point for this circuit
-   * which is not suppose to happen. */
+   * which is not supposed to happen. */
   tor_assert_nonfatal_unreached();
 
  end:
@@ -755,24 +765,13 @@ STATIC extend_info_t *
 desc_intro_point_to_extend_info(const hs_desc_intro_point_t *ip)
 {
   extend_info_t *ei;
-  smartlist_t *lspecs = smartlist_new();
 
   tor_assert(ip);
 
-  /* We first encode the descriptor link specifiers into the binary
-   * representation which is a trunnel object. */
-  SMARTLIST_FOREACH_BEGIN(ip->link_specifiers,
-                          const hs_desc_link_specifier_t *, desc_lspec) {
-    link_specifier_t *lspec = hs_desc_lspec_to_trunnel(desc_lspec);
-    smartlist_add(lspecs, lspec);
-  } SMARTLIST_FOREACH_END(desc_lspec);
-
   /* Explicitly put the direct connection option to 0 because this is client
    * side and there is no such thing as a non anonymous client. */
-  ei = hs_get_extend_info_from_lspecs(lspecs, &ip->onion_key, 0);
+  ei = hs_get_extend_info_from_lspecs(ip->link_specifiers, &ip->onion_key, 0);
 
-  SMARTLIST_FOREACH(lspecs, link_specifier_t *, ls, link_specifier_free(ls));
-  smartlist_free(lspecs);
   return ei;
 }
 
@@ -1543,7 +1542,10 @@ parse_auth_file_content(const char *client_key_str)
   auth = tor_malloc_zero(sizeof(hs_client_service_authorization_t));
   if (base32_decode((char *) auth->enc_seckey.secret_key,
                     sizeof(auth->enc_seckey.secret_key),
-                    seckey_b32, strlen(seckey_b32)) < 0) {
+                    seckey_b32, strlen(seckey_b32)) !=
+      sizeof(auth->enc_seckey.secret_key)) {
+    log_warn(LD_REND, "Client authorization encoded base32 private key "
+                      "can't be decoded: %s", seckey_b32);
     goto err;
   }
   strncpy(auth->onion_address, onion_address, HS_SERVICE_ADDR_LEN_BASE32);
diff --git a/src/feature/hs/hs_client.h b/src/feature/hs/hs_client.h
index dadfa024b..96a96755f 100644
--- a/src/feature/hs/hs_client.h
+++ b/src/feature/hs/hs_client.h
@@ -44,6 +44,10 @@ typedef struct hs_client_service_authorization_t {
 void hs_client_note_connection_attempt_succeeded(
                                        const edge_connection_t *conn);
 
+void hs_client_launch_v3_desc_fetch(
+                               const ed25519_public_key_t *onion_identity_pk,
+                               const smartlist_t *hsdirs);
+
 int hs_client_decode_descriptor(
                      const char *desc_str,
                      const ed25519_public_key_t *service_identity_pk,
diff --git a/src/feature/hs/hs_common.c b/src/feature/hs/hs_common.c
index ebe49f09a..a5747fe17 100644
--- a/src/feature/hs/hs_common.c
+++ b/src/feature/hs/hs_common.c
@@ -926,7 +926,8 @@ hs_parse_address(const char *address, ed25519_public_key_t *key_out,
   }
 
   /* Decode address so we can extract needed fields. */
-  if (base32_decode(decoded, sizeof(decoded), address, strlen(address)) < 0) {
+  if (base32_decode(decoded, sizeof(decoded), address, strlen(address))
+      != sizeof(decoded)) {
     log_warn(LD_REND, "Service address %s can't be decoded.",
              escaped_safe_str(address));
     goto invalid;
@@ -940,7 +941,7 @@ hs_parse_address(const char *address, ed25519_public_key_t *key_out,
   return -1;
 }
 
-/* Validate a given onion address. The length, the base32 decoding and
+/* Validate a given onion address. The length, the base32 decoding, and
  * checksum are validated. Return 1 if valid else 0. */
 int
 hs_address_is_valid(const char *address)
@@ -955,7 +956,7 @@ hs_address_is_valid(const char *address)
     goto invalid;
   }
 
-  /* Get the checksum it's suppose to be and compare it with what we have
+  /* Get the checksum it's supposed to be and compare it with what we have
    * encoded in the address. */
   build_hs_checksum(&service_pubkey, version, target_checksum);
   if (tor_memcmp(checksum, target_checksum, sizeof(checksum))) {
@@ -983,7 +984,7 @@ hs_address_is_valid(const char *address)
  * The returned address is base32 encoded and put in addr_out. The caller MUST
  * make sure the addr_out is at least HS_SERVICE_ADDR_LEN_BASE32 + 1 long.
  *
- * Format is as follow:
+ * Format is as follows:
  *     base32(PUBKEY || CHECKSUM || VERSION)
  *     CHECKSUM = H(".onion checksum" || PUBKEY || VERSION)
  * */
@@ -1009,24 +1010,6 @@ hs_build_address(const ed25519_public_key_t *key, uint8_t version,
   tor_assert(hs_address_is_valid(addr_out));
 }
 
-/* Return a newly allocated copy of lspec. */
-link_specifier_t *
-hs_link_specifier_dup(const link_specifier_t *lspec)
-{
-  link_specifier_t *result = link_specifier_new();
-  memcpy(result, lspec, sizeof(*result));
-  /* The unrecognized field is a dynamic array so make sure to copy its
-   * content and not the pointer. */
-  link_specifier_setlen_un_unrecognized(
-                  result, link_specifier_getlen_un_unrecognized(lspec));
-  if (link_specifier_getlen_un_unrecognized(result)) {
-    memcpy(link_specifier_getarray_un_unrecognized(result),
-           link_specifier_getconstarray_un_unrecognized(lspec),
-           link_specifier_getlen_un_unrecognized(result));
-  }
-  return result;
-}
-
 /* From a given ed25519 public key pk and an optional secret, compute a
  * blinded public key and put it in blinded_pk_out. This is only useful to
  * the client side because the client only has access to the identity public
@@ -1042,7 +1025,7 @@ hs_build_blinded_pubkey(const ed25519_public_key_t *pk,
 
   tor_assert(pk);
   tor_assert(blinded_pk_out);
-  tor_assert(!tor_mem_is_zero((char *) pk, ED25519_PUBKEY_LEN));
+  tor_assert(!fast_mem_is_zero((char *) pk, ED25519_PUBKEY_LEN));
 
   build_blinded_key_param(pk, secret, secret_len,
                           time_period_num, get_time_period_length(), param);
@@ -1067,8 +1050,8 @@ hs_build_blinded_keypair(const ed25519_keypair_t *kp,
   tor_assert(kp);
   tor_assert(blinded_kp_out);
   /* Extra safety. A zeroed key is bad. */
-  tor_assert(!tor_mem_is_zero((char *) &kp->pubkey, ED25519_PUBKEY_LEN));
-  tor_assert(!tor_mem_is_zero((char *) &kp->seckey, ED25519_SECKEY_LEN));
+  tor_assert(!fast_mem_is_zero((char *) &kp->pubkey, ED25519_PUBKEY_LEN));
+  tor_assert(!fast_mem_is_zero((char *) &kp->seckey, ED25519_SECKEY_LEN));
 
   build_blinded_key_param(&kp->pubkey, secret, secret_len,
                           time_period_num, get_time_period_length(), param);
@@ -1300,15 +1283,15 @@ node_has_hsdir_index(const node_t *node)
 
   /* At this point, since the node has a desc, this node must also have an
    * hsdir index. If not, something went wrong, so BUG out. */
-  if (BUG(tor_mem_is_zero((const char*)node->hsdir_index.fetch,
+  if (BUG(fast_mem_is_zero((const char*)node->hsdir_index.fetch,
                           DIGEST256_LEN))) {
     return 0;
   }
-  if (BUG(tor_mem_is_zero((const char*)node->hsdir_index.store_first,
+  if (BUG(fast_mem_is_zero((const char*)node->hsdir_index.store_first,
                           DIGEST256_LEN))) {
     return 0;
   }
-  if (BUG(tor_mem_is_zero((const char*)node->hsdir_index.store_second,
+  if (BUG(fast_mem_is_zero((const char*)node->hsdir_index.store_second,
                           DIGEST256_LEN))) {
     return 0;
   }
@@ -1606,20 +1589,25 @@ hs_purge_last_hid_serv_requests(void)
 /** Given the list of responsible HSDirs in <b>responsible_dirs</b>, pick the
  *  one that we should use to fetch a descriptor right now. Take into account
  *  previous failed attempts at fetching this descriptor from HSDirs using the
- *  string identifier <b>req_key_str</b>.
+ *  string identifier <b>req_key_str</b>. We return whether we are rate limited
+ *  into *<b>is_rate_limited_out</b> if it is not NULL.
  *
  *  Steals ownership of <b>responsible_dirs</b>.
  *
  *  Return the routerstatus of the chosen HSDir if successful, otherwise return
  *  NULL if no HSDirs are worth trying right now. */
 routerstatus_t *
-hs_pick_hsdir(smartlist_t *responsible_dirs, const char *req_key_str)
+hs_pick_hsdir(smartlist_t *responsible_dirs, const char *req_key_str,
+              bool *is_rate_limited_out)
 {
   smartlist_t *usable_responsible_dirs = smartlist_new();
   const or_options_t *options = get_options();
   routerstatus_t *hs_dir;
   time_t now = time(NULL);
   int excluded_some;
+  bool rate_limited = false;
+  int rate_limited_count = 0;
+  int responsible_dirs_count = smartlist_len(responsible_dirs);
 
   tor_assert(req_key_str);
 
@@ -1639,6 +1627,7 @@ hs_pick_hsdir(smartlist_t *responsible_dirs, const char *req_key_str)
     if (last + hs_hsdir_requery_period(options) >= now ||
         !node || !node_has_preferred_descriptor(node, 0)) {
       SMARTLIST_DEL_CURRENT(responsible_dirs, dir);
+      rate_limited_count++;
       continue;
     }
     if (!routerset_contains_node(options->ExcludeNodes, node)) {
@@ -1646,6 +1635,10 @@ hs_pick_hsdir(smartlist_t *responsible_dirs, const char *req_key_str)
     }
   } SMARTLIST_FOREACH_END(dir);
 
+  if (rate_limited_count > 0 || responsible_dirs_count > 0) {
+    rate_limited = rate_limited_count == responsible_dirs_count;
+  }
+
   excluded_some =
     smartlist_len(usable_responsible_dirs) < smartlist_len(responsible_dirs);
 
@@ -1657,9 +1650,10 @@ hs_pick_hsdir(smartlist_t *responsible_dirs, const char *req_key_str)
   smartlist_free(responsible_dirs);
   smartlist_free(usable_responsible_dirs);
   if (!hs_dir) {
+    const char *warn_str = (rate_limited) ? "we are rate limited." :
+                              "we requested them all recently without success";
     log_info(LD_REND, "Could not pick one of the responsible hidden "
-                      "service directories, because we requested them all "
-                      "recently without success.");
+                      "service directories, because %s.", warn_str);
     if (options->StrictNodes && excluded_some) {
       log_warn(LD_REND, "Could not pick a hidden service directory for the "
                "requested hidden service: they are all either down or "
@@ -1671,17 +1665,23 @@ hs_pick_hsdir(smartlist_t *responsible_dirs, const char *req_key_str)
     hs_lookup_last_hid_serv_request(hs_dir, req_key_str, now, 1);
   }
 
+  if (is_rate_limited_out != NULL) {
+    *is_rate_limited_out = rate_limited;
+  }
+
   return hs_dir;
 }
 
-/* From a list of link specifier, an onion key and if we are requesting a
- * direct connection (ex: single onion service), return a newly allocated
- * extend_info_t object. This function always returns an extend info with
- * an IPv4 address, or NULL.
+/* Given a list of link specifiers lspecs, a curve 25519 onion_key, and
+ * a direct connection boolean direct_conn (true for single onion services),
+ * return a newly allocated extend_info_t object.
+ *
+ * This function always returns an extend info with a valid IP address and
+ * ORPort, or NULL. If direct_conn is false, the IP address is always IPv4.
  *
  * It performs the following checks:
- *  if either IPv4 or legacy ID is missing, return NULL.
- *  if direct_conn, and we can't reach the IPv4 address, return NULL.
+ *  if there is no usable IP address, or legacy ID is missing, return NULL.
+ *  if direct_conn, and we can't reach any IP address, return NULL.
  */
 extend_info_t *
 hs_get_extend_info_from_lspecs(const smartlist_t *lspecs,
@@ -1690,21 +1690,40 @@ hs_get_extend_info_from_lspecs(const smartlist_t *lspecs,
 {
   int have_v4 = 0, have_legacy_id = 0, have_ed25519_id = 0;
   char legacy_id[DIGEST_LEN] = {0};
-  uint16_t port_v4 = 0;
-  tor_addr_t addr_v4;
   ed25519_public_key_t ed25519_pk;
   extend_info_t *info = NULL;
+  tor_addr_port_t ap;
 
-  tor_assert(lspecs);
+  tor_addr_make_null(&ap.addr, AF_UNSPEC);
+  ap.port = 0;
+
+  if (lspecs == NULL) {
+    log_warn(LD_BUG, "Specified link specifiers is null");
+    goto done;
+  }
+
+  if (onion_key == NULL) {
+    log_warn(LD_BUG, "Specified onion key is null");
+    goto done;
+  }
+
+  if (smartlist_len(lspecs) == 0) {
+    log_fn(LOG_PROTOCOL_WARN, LD_REND, "Empty link specifier list.");
+    /* Return NULL. */
+    goto done;
+  }
 
   SMARTLIST_FOREACH_BEGIN(lspecs, const link_specifier_t *, ls) {
     switch (link_specifier_get_ls_type(ls)) {
     case LS_IPV4:
-      /* Skip if we already seen a v4. */
-      if (have_v4) continue;
-      tor_addr_from_ipv4h(&addr_v4,
+      /* Skip if we already seen a v4. If direct_conn is true, we skip this
+       * block because fascist_firewall_choose_address_ls() will set ap. If
+       * direct_conn is false, set ap to the first IPv4 address and port in
+       * the link specifiers.*/
+      if (have_v4 || direct_conn) continue;
+      tor_addr_from_ipv4h(&ap.addr,
                           link_specifier_get_un_ipv4_addr(ls));
-      port_v4 = link_specifier_get_un_ipv4_port(ls);
+      ap.port = link_specifier_get_un_ipv4_port(ls);
       have_v4 = 1;
       break;
     case LS_LEGACY_ID:
@@ -1728,45 +1747,38 @@ hs_get_extend_info_from_lspecs(const smartlist_t *lspecs,
     }
   } SMARTLIST_FOREACH_END(ls);
 
-  /* Legacy ID is mandatory, and we require IPv4. */
-  if (!have_v4 || !have_legacy_id) {
+  /* Choose a preferred address first, but fall back to an allowed address. */
+  if (direct_conn)
+    fascist_firewall_choose_address_ls(lspecs, 0, &ap);
+
+  /* Legacy ID is mandatory, and we require an IP address. */
+  if (!tor_addr_port_is_valid_ap(&ap, 0)) {
+    /* If we're missing the IP address, log a warning and return NULL. */
+    log_info(LD_NET, "Unreachable or invalid IP address in link state");
     goto done;
   }
-
-  /* We know we have IPv4, because we just checked. */
-  if (!direct_conn) {
-    /* All clients can extend to any IPv4 via a 3-hop path. */
-    goto validate;
-  } else if (direct_conn &&
-             fascist_firewall_allows_address_addr(&addr_v4, port_v4,
-                                                  FIREWALL_OR_CONNECTION,
-                                                  0, 0)) {
-    /* Direct connection and we can reach it in IPv4 so go for it. */
-    goto validate;
-
-    /* We will add support for falling back to a 3-hop path in a later
-     * release. */
-  } else {
-    /* If we can't reach IPv4, return NULL. */
+  if (!have_legacy_id) {
+    /* If we're missing the legacy ID, log a warning and return NULL. */
+    log_warn(LD_PROTOCOL, "Missing Legacy ID in link state");
     goto done;
   }
 
-  /* We will add support for IPv6 in a later release. */
+  /* We will add support for falling back to a 3-hop path in a later
+   * release. */
 
- validate:
   /* We'll validate now that the address we've picked isn't a private one. If
-   * it is, are we allowing to extend to private address? */
-  if (!extend_info_addr_is_allowed(&addr_v4)) {
+   * it is, are we allowed to extend to private addresses? */
+  if (!extend_info_addr_is_allowed(&ap.addr)) {
     log_fn(LOG_PROTOCOL_WARN, LD_REND,
            "Requested address is private and we are not allowed to extend to "
-           "it: %s:%u", fmt_addr(&addr_v4), port_v4);
+           "it: %s:%u", fmt_addr(&ap.addr), ap.port);
     goto done;
   }
 
   /* We do have everything for which we think we can connect successfully. */
   info = extend_info_new(NULL, legacy_id,
                          (have_ed25519_id) ? &ed25519_pk : NULL, NULL,
-                         onion_key, &addr_v4, port_v4);
+                         onion_key, &ap.addr, ap.port);
  done:
   return info;
 }
@@ -1827,3 +1839,42 @@ hs_inc_rdv_stream_counter(origin_circuit_t *circ)
     tor_assert_nonfatal_unreached();
   }
 }
+
+/* Return a newly allocated link specifier object that is a copy of dst. */
+link_specifier_t *
+link_specifier_dup(const link_specifier_t *src)
+{
+  link_specifier_t *dup = NULL;
+  uint8_t *buf = NULL;
+
+  if (BUG(!src)) {
+    goto err;
+  }
+
+  ssize_t encoded_len_alloc = link_specifier_encoded_len(src);
+  if (BUG(encoded_len_alloc < 0)) {
+    goto err;
+  }
+
+  buf = tor_malloc_zero(encoded_len_alloc);
+  ssize_t encoded_len_data = link_specifier_encode(buf,
+                                                   encoded_len_alloc,
+                                                   src);
+  if (BUG(encoded_len_data < 0)) {
+    goto err;
+  }
+
+  ssize_t parsed_len = link_specifier_parse(&dup, buf, encoded_len_alloc);
+  if (BUG(parsed_len < 0)) {
+    goto err;
+  }
+
+  goto done;
+
+ err:
+  dup = NULL;
+
+ done:
+  tor_free(buf);
+  return dup;
+}
diff --git a/src/feature/hs/hs_common.h b/src/feature/hs/hs_common.h
index a44505930..3009780d9 100644
--- a/src/feature/hs/hs_common.h
+++ b/src/feature/hs/hs_common.h
@@ -217,8 +217,6 @@ uint64_t hs_get_time_period_num(time_t now);
 uint64_t hs_get_next_time_period_num(time_t now);
 time_t hs_get_start_time_of_next_time_period(time_t now);
 
-link_specifier_t *hs_link_specifier_dup(const link_specifier_t *lspec);
-
 MOCK_DECL(int, hs_in_period_between_tp_and_srv,
           (const networkstatus_t *consensus, time_t now));
 
@@ -243,7 +241,8 @@ void hs_get_responsible_hsdirs(const struct ed25519_public_key_t *blinded_pk,
                               int use_second_hsdir_index,
                               int for_fetching, smartlist_t *responsible_dirs);
 routerstatus_t *hs_pick_hsdir(smartlist_t *responsible_dirs,
-                              const char *req_key_str);
+                              const char *req_key_str,
+                              bool *is_rate_limited_out);
 
 time_t hs_hsdir_requery_period(const or_options_t *options);
 time_t hs_lookup_last_hid_serv_request(routerstatus_t *hs_dir,
@@ -262,6 +261,8 @@ extend_info_t *hs_get_extend_info_from_lspecs(const smartlist_t *lspecs,
                           const struct curve25519_public_key_t *onion_key,
                           int direct_conn);
 
+link_specifier_t *link_specifier_dup(const link_specifier_t *src);
+
 #ifdef HS_COMMON_PRIVATE
 
 STATIC void get_disaster_srv(uint64_t time_period_num, uint8_t *srv_out);
diff --git a/src/feature/hs/hs_config.c b/src/feature/hs/hs_config.c
index ee4499ef5..87f625759 100644
--- a/src/feature/hs/hs_config.c
+++ b/src/feature/hs/hs_config.c
@@ -496,15 +496,6 @@ config_generic_service(const config_line_t *line_,
    * becomes a single onion service. */
   if (rend_service_non_anonymous_mode_enabled(options)) {
     config->is_single_onion = 1;
-    /* We will add support for IPv6-only v3 single onion services in a future
-     * Tor version. This won't catch "ReachableAddresses reject *4", but that
-     * option doesn't work anyway. */
-    if (options->ClientUseIPv4 == 0 && config->version == HS_VERSION_THREE) {
-      log_warn(LD_CONFIG, "IPv6-only v3 single onion services are not "
-               "supported. Set HiddenServiceSingleHopMode 0 and "
-               "HiddenServiceNonAnonymousMode 0, or set ClientUseIPv4 1.");
-      goto err;
-    }
   }
 
   /* Success */
diff --git a/src/feature/hs/hs_control.c b/src/feature/hs/hs_control.c
index 9970fdd12..abb421345 100644
--- a/src/feature/hs/hs_control.c
+++ b/src/feature/hs/hs_control.c
@@ -7,9 +7,10 @@
  **/
 
 #include "core/or/or.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "lib/crypt_ops/crypto_format.h"
 #include "lib/crypt_ops/crypto_util.h"
+#include "feature/hs/hs_client.h"
 #include "feature/hs/hs_common.h"
 #include "feature/hs/hs_control.h"
 #include "feature/hs/hs_descriptor.h"
@@ -73,10 +74,7 @@ hs_control_desc_event_failed(const hs_ident_dir_conn_t *ident,
   tor_assert(reason);
 
   /* Build onion address and encoded blinded key. */
-  IF_BUG_ONCE(ed25519_public_to_base64(base64_blinded_pk,
-                                       &ident->blinded_pk) < 0) {
-    return;
-  }
+  ed25519_public_to_base64(base64_blinded_pk, &ident->blinded_pk);
   hs_build_address(&ident->identity_pk, HS_VERSION_THREE, onion_address);
 
   control_event_hsv3_descriptor_failed(onion_address, base64_blinded_pk,
@@ -98,10 +96,7 @@ hs_control_desc_event_received(const hs_ident_dir_conn_t *ident,
   tor_assert(hsdir_id_digest);
 
   /* Build onion address and encoded blinded key. */
-  IF_BUG_ONCE(ed25519_public_to_base64(base64_blinded_pk,
-                                       &ident->blinded_pk) < 0) {
-    return;
-  }
+  ed25519_public_to_base64(base64_blinded_pk, &ident->blinded_pk);
   hs_build_address(&ident->identity_pk, HS_VERSION_THREE, onion_address);
 
   control_event_hsv3_descriptor_received(onion_address, base64_blinded_pk,
@@ -122,9 +117,7 @@ hs_control_desc_event_created(const char *onion_address,
   tor_assert(blinded_pk);
 
   /* Build base64 encoded blinded key. */
-  IF_BUG_ONCE(ed25519_public_to_base64(base64_blinded_pk, blinded_pk) < 0) {
-    return;
-  }
+  ed25519_public_to_base64(base64_blinded_pk, blinded_pk);
 
   /* Version 3 doesn't use the replica number in its descriptor ID computation
    * so we pass negative value so the control port subsystem can ignore it. */
@@ -150,9 +143,7 @@ hs_control_desc_event_upload(const char *onion_address,
   tor_assert(hsdir_index);
 
   /* Build base64 encoded blinded key. */
-  IF_BUG_ONCE(ed25519_public_to_base64(base64_blinded_pk, blinded_pk) < 0) {
-    return;
-  }
+  ed25519_public_to_base64(base64_blinded_pk, blinded_pk);
 
   control_event_hs_descriptor_upload(onion_address, hsdir_id_digest,
                                      base64_blinded_pk,
@@ -195,10 +186,7 @@ hs_control_desc_event_content(const hs_ident_dir_conn_t *ident,
   tor_assert(hsdir_id_digest);
 
   /* Build onion address and encoded blinded key. */
-  IF_BUG_ONCE(ed25519_public_to_base64(base64_blinded_pk,
-                                       &ident->blinded_pk) < 0) {
-    return;
-  }
+  ed25519_public_to_base64(base64_blinded_pk, &ident->blinded_pk);
   hs_build_address(&ident->identity_pk, HS_VERSION_THREE, onion_address);
 
   control_event_hs_descriptor_content(onion_address, base64_blinded_pk,
@@ -259,3 +247,16 @@ hs_control_hspost_command(const char *body, const char *onion_address,
   smartlist_free(hsdirs);
   return ret;
 }
+
+/* With a given <b>onion_identity_pk</b>, fetch its descriptor, optionally
+ * using the list of directory servers given in <b>hsdirs</b>, or a random
+ * server if it is NULL. This function calls hs_client_launch_v3_desc_fetch().
+ */
+void
+hs_control_hsfetch_command(const ed25519_public_key_t *onion_identity_pk,
+                           const smartlist_t *hsdirs)
+{
+  tor_assert(onion_identity_pk);
+
+  hs_client_launch_v3_desc_fetch(onion_identity_pk, hsdirs);
+}
diff --git a/src/feature/hs/hs_control.h b/src/feature/hs/hs_control.h
index f7ab64265..b55e4c53c 100644
--- a/src/feature/hs/hs_control.h
+++ b/src/feature/hs/hs_control.h
@@ -48,5 +48,9 @@ void hs_control_desc_event_content(const hs_ident_dir_conn_t *ident,
 int hs_control_hspost_command(const char *body, const char *onion_address,
                               const smartlist_t *hsdirs_rs);
 
+/* Command "HSFETCH [...]" */
+void hs_control_hsfetch_command(const ed25519_public_key_t *onion_identity_pk,
+                                const smartlist_t *hsdirs);
+
 #endif /* !defined(TOR_HS_CONTROL_H) */
 
diff --git a/src/feature/hs/hs_descriptor.c b/src/feature/hs/hs_descriptor.c
index b09d50e01..a8796c002 100644
--- a/src/feature/hs/hs_descriptor.c
+++ b/src/feature/hs/hs_descriptor.c
@@ -324,12 +324,11 @@ encode_link_specifiers(const smartlist_t *specs)
 
   link_specifier_list_set_n_spec(lslist, smartlist_len(specs));
 
-  SMARTLIST_FOREACH_BEGIN(specs, const hs_desc_link_specifier_t *,
+  SMARTLIST_FOREACH_BEGIN(specs, const link_specifier_t *,
                           spec) {
-    link_specifier_t *ls = hs_desc_lspec_to_trunnel(spec);
-    if (ls) {
-      link_specifier_list_add_spec(lslist, ls);
-    }
+    link_specifier_t *ls = link_specifier_dup(spec);
+    tor_assert(ls);
+    link_specifier_list_add_spec(lslist, ls);
   } SMARTLIST_FOREACH_END(spec);
 
   {
@@ -404,9 +403,7 @@ encode_enc_key(const hs_desc_intro_point_t *ip)
   tor_assert(ip);
 
   /* Base64 encode the encryption key for the "enc-key" field. */
-  if (curve25519_public_to_base64(key_b64, &ip->enc_key) < 0) {
-    goto done;
-  }
+  curve25519_public_to_base64(key_b64, &ip->enc_key);
   if (tor_cert_encode_ed22519(ip->enc_key_cert, &encoded_cert) < 0) {
     goto done;
   }
@@ -422,7 +419,7 @@ encode_enc_key(const hs_desc_intro_point_t *ip)
 }
 
 /* Encode an introduction point onion key. Return a newly allocated string
- * with it. On failure, return NULL. */
+ * with it. Can not fail. */
 static char *
 encode_onion_key(const hs_desc_intro_point_t *ip)
 {
@@ -432,12 +429,9 @@ encode_onion_key(const hs_desc_intro_point_t *ip)
   tor_assert(ip);
 
   /* Base64 encode the encryption key for the "onion-key" field. */
-  if (curve25519_public_to_base64(key_b64, &ip->onion_key) < 0) {
-    goto done;
-  }
+  curve25519_public_to_base64(key_b64, &ip->onion_key);
   tor_asprintf(&encoded, "%s ntor %s", str_ip_onion_key, key_b64);
 
- done:
   return encoded;
 }
 
@@ -684,7 +678,7 @@ get_auth_client_str(const hs_desc_authorized_client_t *client)
   char encrypted_cookie_b64[HS_DESC_ENCRYPED_COOKIE_LEN * 2];
 
 #define ASSERT_AND_BASE64(field) STMT_BEGIN                        \
-  tor_assert(!tor_mem_is_zero((char *) client->field,              \
+  tor_assert(!fast_mem_is_zero((char *) client->field,              \
                               sizeof(client->field)));             \
   ret = base64_encode_nopad(field##_b64, sizeof(field##_b64),      \
                             client->field, sizeof(client->field)); \
@@ -798,8 +792,8 @@ get_inner_encrypted_layer_plaintext(const hs_descriptor_t *desc)
 /* Create the middle layer of the descriptor, which includes the client auth
  * data and the encrypted inner layer (provided as a base64 string at
  * <b>layer2_b64_ciphertext</b>). Return a newly-allocated string with the
- * layer plaintext, or NULL if an error occurred. It's the responsibility of
- * the caller to free the returned string. */
+ * layer plaintext. It's the responsibility of the caller to free the returned
+ * string. Can not fail. */
 static char *
 get_outer_encrypted_layer_plaintext(const hs_descriptor_t *desc,
                                     const char *layer2_b64_ciphertext)
@@ -815,13 +809,10 @@ get_outer_encrypted_layer_plaintext(const hs_descriptor_t *desc,
     const curve25519_public_key_t *ephemeral_pubkey;
 
     ephemeral_pubkey = &desc->superencrypted_data.auth_ephemeral_pubkey;
-    tor_assert(!tor_mem_is_zero((char *) ephemeral_pubkey->public_key,
+    tor_assert(!fast_mem_is_zero((char *) ephemeral_pubkey->public_key,
                                 CURVE25519_PUBKEY_LEN));
 
-    if (curve25519_public_to_base64(ephemeral_key_base64,
-                                    ephemeral_pubkey) < 0) {
-      goto done;
-    }
+    curve25519_public_to_base64(ephemeral_key_base64, ephemeral_pubkey);
     smartlist_add_asprintf(lines, "%s %s\n",
                            str_desc_auth_key, ephemeral_key_base64);
 
@@ -846,7 +837,6 @@ get_outer_encrypted_layer_plaintext(const hs_descriptor_t *desc,
 
   layer1_str = smartlist_join_strings(lines, "", 0, NULL);
 
- done:
   /* We need to memwipe all lines because it contains the ephemeral key */
   SMARTLIST_FOREACH(lines, char *, a, memwipe(a, 0, strlen(a)));
   SMARTLIST_FOREACH(lines, char *, a, tor_free(a));
@@ -1092,11 +1082,7 @@ desc_encode_v3(const hs_descriptor_t *desc,
       tor_free(encoded_str);
       goto err;
     }
-    if (ed25519_signature_to_base64(ed_sig_b64, &sig) < 0) {
-      log_warn(LD_BUG, "Can't base64 encode descriptor signature!");
-      tor_free(encoded_str);
-      goto err;
-    }
+    ed25519_signature_to_base64(ed_sig_b64, &sig);
     /* Create the signature line. */
     smartlist_add_asprintf(lines, "%s %s", str_signature, ed_sig_b64);
   }
@@ -1190,52 +1176,22 @@ decode_link_specifiers(const char *encoded)
   results = smartlist_new();
 
   for (i = 0; i < link_specifier_list_getlen_spec(specs); i++) {
-    hs_desc_link_specifier_t *hs_spec;
     link_specifier_t *ls = link_specifier_list_get_spec(specs, i);
-    tor_assert(ls);
-
-    hs_spec = tor_malloc_zero(sizeof(*hs_spec));
-    hs_spec->type = link_specifier_get_ls_type(ls);
-    switch (hs_spec->type) {
-    case LS_IPV4:
-      tor_addr_from_ipv4h(&hs_spec->u.ap.addr,
-                          link_specifier_get_un_ipv4_addr(ls));
-      hs_spec->u.ap.port = link_specifier_get_un_ipv4_port(ls);
-      break;
-    case LS_IPV6:
-      tor_addr_from_ipv6_bytes(&hs_spec->u.ap.addr, (const char *)
-                               link_specifier_getarray_un_ipv6_addr(ls));
-      hs_spec->u.ap.port = link_specifier_get_un_ipv6_port(ls);
-      break;
-    case LS_LEGACY_ID:
-      /* Both are known at compile time so let's make sure they are the same
-       * else we can copy memory out of bound. */
-      tor_assert(link_specifier_getlen_un_legacy_id(ls) ==
-                 sizeof(hs_spec->u.legacy_id));
-      memcpy(hs_spec->u.legacy_id, link_specifier_getarray_un_legacy_id(ls),
-             sizeof(hs_spec->u.legacy_id));
-      break;
-    case LS_ED25519_ID:
-      /* Both are known at compile time so let's make sure they are the same
-       * else we can copy memory out of bound. */
-      tor_assert(link_specifier_getlen_un_ed25519_id(ls) ==
-                 sizeof(hs_spec->u.ed25519_id));
-      memcpy(hs_spec->u.ed25519_id,
-             link_specifier_getconstarray_un_ed25519_id(ls),
-             sizeof(hs_spec->u.ed25519_id));
-      break;
-    default:
-      tor_free(hs_spec);
+    if (BUG(!ls)) {
       goto err;
     }
-
-    smartlist_add(results, hs_spec);
+    link_specifier_t *ls_dup = link_specifier_dup(ls);
+    if (BUG(!ls_dup)) {
+      goto err;
+    }
+    smartlist_add(results, ls_dup);
   }
 
   goto done;
  err:
   if (results) {
-    SMARTLIST_FOREACH(results, hs_desc_link_specifier_t *, s, tor_free(s));
+    SMARTLIST_FOREACH(results, link_specifier_t *, s,
+                      link_specifier_free(s));
     smartlist_free(results);
     results = NULL;
   }
@@ -1465,12 +1421,12 @@ decrypt_descriptor_cookie(const hs_descriptor_t *desc,
   tor_assert(desc);
   tor_assert(client);
   tor_assert(client_auth_sk);
-  tor_assert(!tor_mem_is_zero(
+  tor_assert(!fast_mem_is_zero(
         (char *) &desc->superencrypted_data.auth_ephemeral_pubkey,
         sizeof(desc->superencrypted_data.auth_ephemeral_pubkey)));
-  tor_assert(!tor_mem_is_zero((char *) client_auth_sk,
+  tor_assert(!fast_mem_is_zero((char *) client_auth_sk,
                               sizeof(*client_auth_sk)));
-  tor_assert(!tor_mem_is_zero((char *) desc->subcredential, DIGEST256_LEN));
+  tor_assert(!fast_mem_is_zero((char *) desc->subcredential, DIGEST256_LEN));
 
   /* Get the KEYS component to derive the CLIENT-ID and COOKIE-KEY. */
   keystream_length =
@@ -2012,6 +1968,7 @@ decode_intro_points(const hs_descriptor_t *desc,
   SMARTLIST_FOREACH(intro_points, char *, a, tor_free(a));
   smartlist_free(intro_points);
 }
+
 /* Return 1 iff the given base64 encoded signature in b64_sig from the encoded
  * descriptor in encoded_desc validates the descriptor content. */
 STATIC int
@@ -2615,7 +2572,7 @@ hs_desc_decode_descriptor(const char *encoded,
 
   /* Subcredentials are not optional. */
   if (BUG(!subcredential ||
-          tor_mem_is_zero((char*)subcredential, DIGEST256_LEN))) {
+          fast_mem_is_zero((char*)subcredential, DIGEST256_LEN))) {
     log_warn(LD_GENERAL, "Tried to decrypt without subcred. Impossible!");
     goto err;
   }
@@ -2878,8 +2835,8 @@ hs_desc_intro_point_free_(hs_desc_intro_point_t *ip)
     return;
   }
   if (ip->link_specifiers) {
-    SMARTLIST_FOREACH(ip->link_specifiers, hs_desc_link_specifier_t *,
-                      ls, hs_desc_link_specifier_free(ls));
+    SMARTLIST_FOREACH(ip->link_specifiers, link_specifier_t *,
+                      ls, link_specifier_free(ls));
     smartlist_free(ip->link_specifiers);
   }
   tor_cert_free(ip->auth_key_cert);
@@ -2928,13 +2885,13 @@ hs_desc_build_authorized_client(const uint8_t *subcredential,
   tor_assert(descriptor_cookie);
   tor_assert(client_out);
   tor_assert(subcredential);
-  tor_assert(!tor_mem_is_zero((char *) auth_ephemeral_sk,
+  tor_assert(!fast_mem_is_zero((char *) auth_ephemeral_sk,
                               sizeof(*auth_ephemeral_sk)));
-  tor_assert(!tor_mem_is_zero((char *) client_auth_pk,
+  tor_assert(!fast_mem_is_zero((char *) client_auth_pk,
                               sizeof(*client_auth_pk)));
-  tor_assert(!tor_mem_is_zero((char *) descriptor_cookie,
+  tor_assert(!fast_mem_is_zero((char *) descriptor_cookie,
                               HS_DESC_DESCRIPTOR_COOKIE_LEN));
-  tor_assert(!tor_mem_is_zero((char *) subcredential,
+  tor_assert(!fast_mem_is_zero((char *) subcredential,
                               DIGEST256_LEN));
 
   /* Get the KEYS part so we can derive the CLIENT-ID and COOKIE-KEY. */
@@ -2972,69 +2929,6 @@ hs_desc_authorized_client_free_(hs_desc_authorized_client_t *client)
   tor_free(client);
 }
 
-/* Free the given descriptor link specifier. */
-void
-hs_desc_link_specifier_free_(hs_desc_link_specifier_t *ls)
-{
-  if (ls == NULL) {
-    return;
-  }
-  tor_free(ls);
-}
-
-/* Return a newly allocated descriptor link specifier using the given extend
- * info and requested type. Return NULL on error. */
-hs_desc_link_specifier_t *
-hs_desc_link_specifier_new(const extend_info_t *info, uint8_t type)
-{
-  hs_desc_link_specifier_t *ls = NULL;
-
-  tor_assert(info);
-
-  ls = tor_malloc_zero(sizeof(*ls));
-  ls->type = type;
-  switch (ls->type) {
-  case LS_IPV4:
-    if (info->addr.family != AF_INET) {
-      goto err;
-    }
-    tor_addr_copy(&ls->u.ap.addr, &info->addr);
-    ls->u.ap.port = info->port;
-    break;
-  case LS_IPV6:
-    if (info->addr.family != AF_INET6) {
-      goto err;
-    }
-    tor_addr_copy(&ls->u.ap.addr, &info->addr);
-    ls->u.ap.port = info->port;
-    break;
-  case LS_LEGACY_ID:
-    /* Bug out if the identity digest is not set */
-    if (BUG(tor_mem_is_zero(info->identity_digest,
-                            sizeof(info->identity_digest)))) {
-      goto err;
-    }
-    memcpy(ls->u.legacy_id, info->identity_digest, sizeof(ls->u.legacy_id));
-    break;
-  case LS_ED25519_ID:
-    /* ed25519 keys are optional for intro points */
-    if (ed25519_public_key_is_zero(&info->ed_identity)) {
-      goto err;
-    }
-    memcpy(ls->u.ed25519_id, info->ed_identity.pubkey,
-           sizeof(ls->u.ed25519_id));
-    break;
-  default:
-    /* Unknown type is code flow error. */
-    tor_assert(0);
-  }
-
-  return ls;
- err:
-  tor_free(ls);
-  return NULL;
-}
-
 /* From the given descriptor, remove and free every introduction point. */
 void
 hs_descriptor_clear_intro_points(hs_descriptor_t *desc)
@@ -3050,59 +2944,3 @@ hs_descriptor_clear_intro_points(hs_descriptor_t *desc)
     smartlist_clear(ips);
   }
 }
-
-/* From a descriptor link specifier object spec, returned a newly allocated
- * link specifier object that is the encoded representation of spec. Return
- * NULL on error. */
-link_specifier_t *
-hs_desc_lspec_to_trunnel(const hs_desc_link_specifier_t *spec)
-{
-  tor_assert(spec);
-
-  link_specifier_t *ls = link_specifier_new();
-  link_specifier_set_ls_type(ls, spec->type);
-
-  switch (spec->type) {
-  case LS_IPV4:
-    link_specifier_set_un_ipv4_addr(ls,
-                                    tor_addr_to_ipv4h(&spec->u.ap.addr));
-    link_specifier_set_un_ipv4_port(ls, spec->u.ap.port);
-    /* Four bytes IPv4 and two bytes port. */
-    link_specifier_set_ls_len(ls, sizeof(spec->u.ap.addr.addr.in_addr) +
-                                  sizeof(spec->u.ap.port));
-    break;
-  case LS_IPV6:
-  {
-    size_t addr_len = link_specifier_getlen_un_ipv6_addr(ls);
-    const uint8_t *in6_addr = tor_addr_to_in6_addr8(&spec->u.ap.addr);
-    uint8_t *ipv6_array = link_specifier_getarray_un_ipv6_addr(ls);
-    memcpy(ipv6_array, in6_addr, addr_len);
-    link_specifier_set_un_ipv6_port(ls, spec->u.ap.port);
-    /* Sixteen bytes IPv6 and two bytes port. */
-    link_specifier_set_ls_len(ls, addr_len + sizeof(spec->u.ap.port));
-    break;
-  }
-  case LS_LEGACY_ID:
-  {
-    size_t legacy_id_len = link_specifier_getlen_un_legacy_id(ls);
-    uint8_t *legacy_id_array = link_specifier_getarray_un_legacy_id(ls);
-    memcpy(legacy_id_array, spec->u.legacy_id, legacy_id_len);
-    link_specifier_set_ls_len(ls, legacy_id_len);
-    break;
-  }
-  case LS_ED25519_ID:
-  {
-    size_t ed25519_id_len = link_specifier_getlen_un_ed25519_id(ls);
-    uint8_t *ed25519_id_array = link_specifier_getarray_un_ed25519_id(ls);
-    memcpy(ed25519_id_array, spec->u.ed25519_id, ed25519_id_len);
-    link_specifier_set_ls_len(ls, ed25519_id_len);
-    break;
-  }
-  default:
-    tor_assert_nonfatal_unreached();
-    link_specifier_free(ls);
-    ls = NULL;
-  }
-
-  return ls;
-}
diff --git a/src/feature/hs/hs_descriptor.h b/src/feature/hs/hs_descriptor.h
index 04a8e16d6..dbe0cb1c9 100644
--- a/src/feature/hs/hs_descriptor.h
+++ b/src/feature/hs/hs_descriptor.h
@@ -69,28 +69,10 @@ typedef enum {
   HS_DESC_AUTH_ED25519 = 1
 } hs_desc_auth_type_t;
 
-/* Link specifier object that contains information on how to extend to the
- * relay that is the address, port and handshake type. */
-typedef struct hs_desc_link_specifier_t {
-  /* Indicate the type of link specifier. See trunnel ed25519_cert
-   * specification. */
-  uint8_t type;
-
-  /* It must be one of these types, can't be more than one. */
-  union {
-    /* IP address and port of the relay use to extend. */
-    tor_addr_port_t ap;
-    /* Legacy identity. A 20-byte SHA1 identity fingerprint. */
-    uint8_t legacy_id[DIGEST_LEN];
-    /* ed25519 identity. A 32-byte key. */
-    uint8_t ed25519_id[ED25519_PUBKEY_LEN];
-  } u;
-} hs_desc_link_specifier_t;
-
 /* Introduction point information located in a descriptor. */
 typedef struct hs_desc_intro_point_t {
   /* Link specifier(s) which details how to extend to the relay. This list
-   * contains hs_desc_link_specifier_t object. It MUST have at least one. */
+   * contains link_specifier_t objects. It MUST have at least one. */
   smartlist_t *link_specifiers;
 
   /* Onion key of the introduction point used to extend to it for the ntor
@@ -261,12 +243,6 @@ void hs_desc_encrypted_data_free_(hs_desc_encrypted_data_t *desc);
 #define hs_desc_encrypted_data_free(desc) \
   FREE_AND_NULL(hs_desc_encrypted_data_t, hs_desc_encrypted_data_free_, (desc))
 
-void hs_desc_link_specifier_free_(hs_desc_link_specifier_t *ls);
-#define hs_desc_link_specifier_free(ls) \
-  FREE_AND_NULL(hs_desc_link_specifier_t, hs_desc_link_specifier_free_, (ls))
-
-hs_desc_link_specifier_t *hs_desc_link_specifier_new(
-                                  const extend_info_t *info, uint8_t type);
 void hs_descriptor_clear_intro_points(hs_descriptor_t *desc);
 
 MOCK_DECL(int,
@@ -299,9 +275,6 @@ void hs_desc_authorized_client_free_(hs_desc_authorized_client_t *client);
   FREE_AND_NULL(hs_desc_authorized_client_t, \
                 hs_desc_authorized_client_free_, (client))
 
-link_specifier_t *hs_desc_lspec_to_trunnel(
-                                   const hs_desc_link_specifier_t *spec);
-
 hs_desc_authorized_client_t *hs_desc_build_fake_authorized_client(void);
 void hs_desc_build_authorized_client(const uint8_t *subcredential,
                                      const curve25519_public_key_t *
diff --git a/src/feature/hs/hs_intropoint.c b/src/feature/hs/hs_intropoint.c
index 7717ed53d..9333060e7 100644
--- a/src/feature/hs/hs_intropoint.c
+++ b/src/feature/hs/hs_intropoint.c
@@ -392,7 +392,7 @@ validate_introduce1_parsed_cell(const trn_cell_introduce1_t *cell)
    * safety net here. The legacy ID must be zeroes in this case. */
   legacy_key_id_len = trn_cell_introduce1_getlen_legacy_key_id(cell);
   legacy_key_id = trn_cell_introduce1_getconstarray_legacy_key_id(cell);
-  if (BUG(!tor_mem_is_zero((char *) legacy_key_id, legacy_key_id_len))) {
+  if (BUG(!fast_mem_is_zero((char *) legacy_key_id, legacy_key_id_len))) {
     goto invalid;
   }
 
@@ -518,7 +518,7 @@ introduce1_cell_is_legacy(const uint8_t *request)
 
   /* If the first 20 bytes of the cell (DIGEST_LEN) are NOT zeroes, it
    * indicates a legacy cell (v2). */
-  if (!tor_mem_is_zero((const char *) request, DIGEST_LEN)) {
+  if (!fast_mem_is_zero((const char *) request, DIGEST_LEN)) {
     /* Legacy cell. */
     return 1;
   }
@@ -602,8 +602,8 @@ hs_intropoint_clear(hs_intropoint_t *ip)
     return;
   }
   tor_cert_free(ip->auth_key_cert);
-  SMARTLIST_FOREACH(ip->link_specifiers, hs_desc_link_specifier_t *, ls,
-                    hs_desc_link_specifier_free(ls));
+  SMARTLIST_FOREACH(ip->link_specifiers, link_specifier_t *, ls,
+                    link_specifier_free(ls));
   smartlist_free(ip->link_specifiers);
   memset(ip, 0, sizeof(hs_intropoint_t));
 }
diff --git a/src/feature/hs/hs_service.c b/src/feature/hs/hs_service.c
index 21eadd299..283591274 100644
--- a/src/feature/hs/hs_service.c
+++ b/src/feature/hs/hs_service.c
@@ -280,9 +280,10 @@ describe_intro_point(const hs_service_intro_point_t *ip)
   const char *legacy_id = NULL;
 
   SMARTLIST_FOREACH_BEGIN(ip->base.link_specifiers,
-                          const hs_desc_link_specifier_t *, lspec) {
-    if (lspec->type == LS_LEGACY_ID) {
-      legacy_id = (const char *) lspec->u.legacy_id;
+                          const link_specifier_t *, lspec) {
+    if (link_specifier_get_ls_type(lspec) == LS_LEGACY_ID) {
+      legacy_id = (const char *)
+        link_specifier_getconstarray_un_legacy_id(lspec);
       break;
     }
   } SMARTLIST_FOREACH_END(lspec);
@@ -426,23 +427,16 @@ service_intro_point_free_void(void *obj)
 }
 
 /* Return a newly allocated service intro point and fully initialized from the
- * given extend_info_t ei if non NULL.
- * If is_legacy is true, we also generate the legacy key.
- * If supports_ed25519_link_handshake_any is true, we add the relay's ed25519
- * key to the link specifiers.
+ * given node_t node, if non NULL.
  *
- * If ei is NULL, returns a hs_service_intro_point_t with an empty link
+ * If node is NULL, returns a hs_service_intro_point_t with an empty link
  * specifier list and no onion key. (This is used for testing.)
  * On any other error, NULL is returned.
  *
- * ei must be an extend_info_t containing an IPv4 address. (We will add supoort
- * for IPv6 in a later release.) When calling extend_info_from_node(), pass
- * 0 in for_direct_connection to make sure ei always has an IPv4 address. */
+ * node must be an node_t with an IPv4 address. */
 STATIC hs_service_intro_point_t *
-service_intro_point_new(const extend_info_t *ei, unsigned int is_legacy,
-                        unsigned int supports_ed25519_link_handshake_any)
+service_intro_point_new(const node_t *node)
 {
-  hs_desc_link_specifier_t *ls;
   hs_service_intro_point_t *ip;
 
   ip = tor_malloc_zero(sizeof(*ip));
@@ -472,12 +466,17 @@ service_intro_point_new(const extend_info_t *ei, unsigned int is_legacy,
   ip->replay_cache = replaycache_new(0, 0);
 
   /* Initialize the base object. We don't need the certificate object. */
-  ip->base.link_specifiers = smartlist_new();
+  ip->base.link_specifiers = node_get_link_specifier_smartlist(node, 0);
+
+  if (node == NULL) {
+    goto done;
+  }
 
   /* Generate the encryption key for this intro point. */
   curve25519_keypair_generate(&ip->enc_key_kp, 0);
-  /* Figure out if this chosen node supports v3 or is legacy only. */
-  if (is_legacy) {
+  /* Figure out if this chosen node supports v3 or is legacy only.
+   * NULL nodes are used in the unit tests. */
+  if (!node_supports_ed25519_hs_intro(node)) {
     ip->base.is_only_legacy = 1;
     /* Legacy mode that is doesn't support v3+ with ed25519 auth key. */
     ip->legacy_key = crypto_pk_new();
@@ -490,40 +489,9 @@ service_intro_point_new(const extend_info_t *ei, unsigned int is_legacy,
     }
   }
 
-  if (ei == NULL) {
-    goto done;
-  }
-
-  /* We'll try to add all link specifiers. Legacy is mandatory.
-   * IPv4 or IPv6 is required, and we always send IPv4. */
-  ls = hs_desc_link_specifier_new(ei, LS_IPV4);
-  /* It is impossible to have an extend info object without a v4. */
-  if (BUG(!ls)) {
-    goto err;
-  }
-  smartlist_add(ip->base.link_specifiers, ls);
-
-  ls = hs_desc_link_specifier_new(ei, LS_LEGACY_ID);
-  /* It is impossible to have an extend info object without an identity
-   * digest. */
-  if (BUG(!ls)) {
-    goto err;
-  }
-  smartlist_add(ip->base.link_specifiers, ls);
-
-  /* ed25519 identity key is optional for intro points. If the node supports
-   * ed25519 link authentication, we include it. */
-  if (supports_ed25519_link_handshake_any) {
-    ls = hs_desc_link_specifier_new(ei, LS_ED25519_ID);
-    if (ls) {
-      smartlist_add(ip->base.link_specifiers, ls);
-    }
-  }
-
-  /* IPv6 is not supported in this release. */
-
-  /* Finally, copy onion key from the extend_info_t object. */
-  memcpy(&ip->onion_key, &ei->curve25519_onion_key, sizeof(ip->onion_key));
+  /* Finally, copy onion key from the node. */
+  memcpy(&ip->onion_key, node_get_curve25519_onion_key(node),
+         sizeof(ip->onion_key));
 
  done:
   return ip;
@@ -656,16 +624,16 @@ get_objects_from_ident(const hs_ident_circuit_t *ident,
  * encountered in the link specifier list. Return NULL if it can't be found.
  *
  * The caller does NOT have ownership of the object, the intro point does. */
-static hs_desc_link_specifier_t *
+static link_specifier_t *
 get_link_spec_by_type(const hs_service_intro_point_t *ip, uint8_t type)
 {
-  hs_desc_link_specifier_t *lnk_spec = NULL;
+  link_specifier_t *lnk_spec = NULL;
 
   tor_assert(ip);
 
   SMARTLIST_FOREACH_BEGIN(ip->base.link_specifiers,
-                          hs_desc_link_specifier_t *, ls) {
-    if (ls->type == type) {
+                          link_specifier_t *, ls) {
+    if (link_specifier_get_ls_type(ls) == type) {
       lnk_spec = ls;
       goto end;
     }
@@ -681,7 +649,7 @@ get_link_spec_by_type(const hs_service_intro_point_t *ip, uint8_t type)
 STATIC const node_t *
 get_node_from_intro_point(const hs_service_intro_point_t *ip)
 {
-  const hs_desc_link_specifier_t *ls;
+  const link_specifier_t *ls;
 
   tor_assert(ip);
 
@@ -690,7 +658,8 @@ get_node_from_intro_point(const hs_service_intro_point_t *ip)
     return NULL;
   }
   /* XXX In the future, we want to only use the ed25519 ID (#22173). */
-  return node_get_by_id((const char *) ls->u.legacy_id);
+  return node_get_by_id(
+    (const char *) link_specifier_getconstarray_un_legacy_id(ls));
 }
 
 /* Given a service intro point, return the extend_info_t for it. This can
@@ -1179,7 +1148,8 @@ parse_authorized_client(const char *client_key_str)
   client = tor_malloc_zero(sizeof(hs_service_authorized_client_t));
   if (base32_decode((char *) client->client_pk.public_key,
                     sizeof(client->client_pk.public_key),
-                    pubkey_b32, strlen(pubkey_b32)) < 0) {
+                    pubkey_b32, strlen(pubkey_b32)) !=
+      sizeof(client->client_pk.public_key)) {
     log_warn(LD_REND, "Client authorization public key cannot be decoded: %s",
              pubkey_b32);
     goto err;
@@ -1261,7 +1231,7 @@ load_client_keys(hs_service_t *service)
     client_key_str = read_file_to_str(client_key_file_path, 0, NULL);
 
     /* If we cannot read the file, continue with the next file. */
-    if (!client_key_str)  {
+    if (!client_key_str) {
       log_warn(LD_REND, "Client authorization file %s can't be read. "
                         "Corrupted or verify permission? Ignoring.",
                client_key_file_path);
@@ -1556,7 +1526,7 @@ remember_failing_intro_point(const hs_service_intro_point_t *ip,
                              hs_service_descriptor_t *desc, time_t now)
 {
   time_t *time_of_failure, *prev_ptr;
-  const hs_desc_link_specifier_t *legacy_ls;
+  const link_specifier_t *legacy_ls;
 
   tor_assert(ip);
   tor_assert(desc);
@@ -1565,22 +1535,13 @@ remember_failing_intro_point(const hs_service_intro_point_t *ip,
   *time_of_failure = now;
   legacy_ls = get_link_spec_by_type(ip, LS_LEGACY_ID);
   tor_assert(legacy_ls);
-  prev_ptr = digestmap_set(desc->intro_points.failed_id,
-                           (const char *) legacy_ls->u.legacy_id,
-                           time_of_failure);
+  prev_ptr = digestmap_set(
+    desc->intro_points.failed_id,
+    (const char *) link_specifier_getconstarray_un_legacy_id(legacy_ls),
+    time_of_failure);
   tor_free(prev_ptr);
 }
 
-/* Copy the descriptor link specifier object from src to dst. */
-static void
-link_specifier_copy(hs_desc_link_specifier_t *dst,
-                    const hs_desc_link_specifier_t *src)
-{
-  tor_assert(dst);
-  tor_assert(src);
-  memcpy(dst, src, sizeof(hs_desc_link_specifier_t));
-}
-
 /* Using a given descriptor signing keypair signing_kp, a service intro point
  * object ip and the time now, setup the content of an already allocated
  * descriptor intro desc_ip.
@@ -1615,9 +1576,14 @@ setup_desc_intro_point(const ed25519_keypair_t *signing_kp,
 
   /* Copy link specifier(s). */
   SMARTLIST_FOREACH_BEGIN(ip->base.link_specifiers,
-                          const hs_desc_link_specifier_t *, ls) {
-    hs_desc_link_specifier_t *copy = tor_malloc_zero(sizeof(*copy));
-    link_specifier_copy(copy, ls);
+                          const link_specifier_t *, ls) {
+    if (BUG(!ls)) {
+      goto done;
+    }
+    link_specifier_t *copy = link_specifier_dup(ls);
+    if (BUG(!copy)) {
+      goto done;
+    }
     smartlist_add(desc_ip->link_specifiers, copy);
   } SMARTLIST_FOREACH_END(ls);
 
@@ -1780,7 +1746,7 @@ build_service_desc_superencrypted(const hs_service_t *service,
          sizeof(curve25519_public_key_t));
 
   /* Test that subcred is not zero because we might use it below */
-  if (BUG(tor_mem_is_zero((char*)desc->desc->subcredential, DIGEST256_LEN))) {
+  if (BUG(fast_mem_is_zero((char*)desc->desc->subcredential, DIGEST256_LEN))) {
     return -1;
   }
 
@@ -1846,9 +1812,9 @@ build_service_desc_plaintext(const hs_service_t *service,
 
   tor_assert(service);
   tor_assert(desc);
-  tor_assert(!tor_mem_is_zero((char *) &desc->blinded_kp,
+  tor_assert(!fast_mem_is_zero((char *) &desc->blinded_kp,
                               sizeof(desc->blinded_kp)));
-  tor_assert(!tor_mem_is_zero((char *) &desc->signing_kp,
+  tor_assert(!fast_mem_is_zero((char *) &desc->signing_kp,
                               sizeof(desc->signing_kp)));
 
   /* Set the subcredential. */
@@ -1898,7 +1864,7 @@ build_service_desc_keys(const hs_service_t *service,
   ed25519_keypair_t kp;
 
   tor_assert(desc);
-  tor_assert(!tor_mem_is_zero((char *) &service->keys.identity_pk,
+  tor_assert(!fast_mem_is_zero((char *) &service->keys.identity_pk,
              ED25519_PUBKEY_LEN));
 
   /* XXX: Support offline key feature (#18098). */
@@ -2105,19 +2071,27 @@ build_all_descriptors(time_t now)
 static hs_service_intro_point_t *
 pick_intro_point(unsigned int direct_conn, smartlist_t *exclude_nodes)
 {
+  const or_options_t *options = get_options();
   const node_t *node;
-  extend_info_t *info = NULL;
   hs_service_intro_point_t *ip = NULL;
   /* Normal 3-hop introduction point flags. */
   router_crn_flags_t flags = CRN_NEED_UPTIME | CRN_NEED_DESC;
   /* Single onion flags. */
   router_crn_flags_t direct_flags = flags | CRN_PREF_ADDR | CRN_DIRECT_CONN;
 
-  node = router_choose_random_node(exclude_nodes, get_options()->ExcludeNodes,
+  node = router_choose_random_node(exclude_nodes, options->ExcludeNodes,
                                    direct_conn ? direct_flags : flags);
-  /* Unable to find a node. When looking for a node for a direct connection,
-   * we could try a 3-hop path instead. We'll add support for this in a later
-   * release. */
+
+  /* If we are in single onion mode, retry node selection for a 3-hop
+   * path */
+  if (direct_conn && !node) {
+    log_info(LD_REND,
+             "Unable to find an intro point that we can connect to "
+             "directly, falling back to a 3-hop path.");
+    node = router_choose_random_node(exclude_nodes, options->ExcludeNodes,
+                                     flags);
+  }
+
   if (!node) {
     goto err;
   }
@@ -2127,43 +2101,17 @@ pick_intro_point(unsigned int direct_conn, smartlist_t *exclude_nodes)
    * we don't want to use that node anymore. */
   smartlist_add(exclude_nodes, (void *) node);
 
-  /* We do this to ease our life but also this call makes appropriate checks
-   * of the node object such as validating ntor support for instance.
-   *
-   * We must provide an extend_info for clients to connect over a 3-hop path,
-   * so we don't pass direct_conn here. */
-  info = extend_info_from_node(node, 0);
-  if (BUG(info == NULL)) {
-    goto err;
-  }
-
-  /* Let's do a basic sanity check here so that we don't end up advertising the
-   * ed25519 identity key of relays that don't actually support the link
-   * protocol */
-  if (!node_supports_ed25519_link_authentication(node, 0)) {
-    tor_assert_nonfatal(ed25519_public_key_is_zero(&info->ed_identity));
-  } else {
-    /* Make sure we *do* have an ed key if we support the link authentication.
-     * Sending an empty key would result in a failure to extend. */
-    tor_assert_nonfatal(!ed25519_public_key_is_zero(&info->ed_identity));
-  }
+  /* Create our objects and populate them with the node information. */
+  ip = service_intro_point_new(node);
 
-  /* Create our objects and populate them with the node information.
-   * We don't care if the intro's link auth is compatible with us, because
-   * we are sending the ed25519 key to a remote client via the descriptor. */
-  ip = service_intro_point_new(info, !node_supports_ed25519_hs_intro(node),
-                               node_supports_ed25519_link_authentication(node,
-                                                                         0));
   if (ip == NULL) {
     goto err;
   }
 
-  log_info(LD_REND, "Picked intro point: %s", extend_info_describe(info));
-  extend_info_free(info);
+  log_info(LD_REND, "Picked intro point: %s", node_describe(node));
   return ip;
  err:
   service_intro_point_free(ip);
-  extend_info_free(info);
   return NULL;
 }
 
@@ -2644,7 +2592,7 @@ launch_intro_point_circuits(hs_service_t *service)
    * circuits using the current map. */
   FOR_EACH_DESCRIPTOR_BEGIN(service, desc) {
     /* Keep a ref on if we need a direct connection. We use this often. */
-    unsigned int direct_conn = service->config.is_single_onion;
+    bool direct_conn = service->config.is_single_onion;
 
     DIGEST256MAP_FOREACH_MODIFY(desc->intro_points.map, key,
                                 hs_service_intro_point_t *, ip) {
@@ -2655,8 +2603,15 @@ launch_intro_point_circuits(hs_service_t *service)
       if (hs_circ_service_get_intro_circ(ip)) {
         continue;
       }
-
       ei = get_extend_info_from_intro_point(ip, direct_conn);
+
+      /* If we can't connect directly to the intro point, get an extend_info
+       * for a multi-hop path instead. */
+      if (ei == NULL && direct_conn) {
+        direct_conn = false;
+        ei = get_extend_info_from_intro_point(ip, 0);
+      }
+
       if (ei == NULL) {
         /* This is possible if we can get a node_t but not the extend info out
          * of it. In this case, we remove the intro point and a new one will
@@ -2668,7 +2623,7 @@ launch_intro_point_circuits(hs_service_t *service)
 
       /* Launch a circuit to the intro point. */
       ip->circuit_retries++;
-      if (hs_circ_launch_intro_point(service, ip, ei) < 0) {
+      if (hs_circ_launch_intro_point(service, ip, ei, direct_conn) < 0) {
         log_info(LD_REND, "Unable to launch intro circuit to node %s "
                           "for service %s.",
                  safe_str_client(extend_info_describe(ei)),
diff --git a/src/feature/hs/hs_service.h b/src/feature/hs/hs_service.h
index ec53f2f23..22aa00b2d 100644
--- a/src/feature/hs/hs_service.h
+++ b/src/feature/hs/hs_service.h
@@ -361,7 +361,7 @@ STATIC hs_service_t *get_first_service(void);
 STATIC hs_service_intro_point_t *service_intro_point_find_by_ident(
                                          const hs_service_t *service,
                                          const hs_ident_circuit_t *ident);
-#endif
+#endif /* defined(TOR_UNIT_TESTS) */
 
 /* Service accessors. */
 STATIC hs_service_t *find_service(hs_service_ht *map,
@@ -369,10 +369,7 @@ STATIC hs_service_t *find_service(hs_service_ht *map,
 STATIC void remove_service(hs_service_ht *map, hs_service_t *service);
 STATIC int register_service(hs_service_ht *map, hs_service_t *service);
 /* Service introduction point functions. */
-STATIC hs_service_intro_point_t *service_intro_point_new(
-                            const extend_info_t *ei,
-                            unsigned int is_legacy,
-                            unsigned int supports_ed25519_link_handshake_any);
+STATIC hs_service_intro_point_t *service_intro_point_new(const node_t *node);
 STATIC void service_intro_point_free_(hs_service_intro_point_t *ip);
 #define service_intro_point_free(ip)                            \
   FREE_AND_NULL(hs_service_intro_point_t,             \
diff --git a/src/feature/hs/hs_stats.h b/src/feature/hs/hs_stats.h
index d89440fac..6700eca15 100644
--- a/src/feature/hs/hs_stats.h
+++ b/src/feature/hs/hs_stats.h
@@ -6,9 +6,13 @@
  * \brief Header file for hs_stats.c
  **/
 
+#ifndef TOR_HS_STATS_H
+#define TOR_HS_STATS_H
+
 void hs_stats_note_introduce2_cell(int is_hsv3);
 uint32_t hs_stats_get_n_introduce2_v3_cells(void);
 uint32_t hs_stats_get_n_introduce2_v2_cells(void);
 void hs_stats_note_service_rendezvous_launch(void);
 uint32_t hs_stats_get_n_rendezvous_launches(void);
 
+#endif /* !defined(TOR_HS_STATS_H) */
diff --git a/src/feature/hs/hsdir_index_st.h b/src/feature/hs/hsdir_index_st.h
index 7d4116d8b..6c86c02f4 100644
--- a/src/feature/hs/hsdir_index_st.h
+++ b/src/feature/hs/hsdir_index_st.h
@@ -20,5 +20,5 @@ struct hsdir_index_t {
   uint8_t store_second[DIGEST256_LEN];
 };
 
-#endif
+#endif /* !defined(HSDIR_INDEX_ST_H) */
 
diff --git a/src/feature/hs_common/shared_random_client.h b/src/feature/hs_common/shared_random_client.h
index 95fe2c65a..c90c52cfe 100644
--- a/src/feature/hs_common/shared_random_client.h
+++ b/src/feature/hs_common/shared_random_client.h
@@ -44,5 +44,5 @@ time_t get_start_time_of_current_round(void);
 
 #endif /* TOR_UNIT_TESTS */
 
-#endif /* TOR_SHARED_RANDOM_CLIENT_H */
+#endif /* !defined(TOR_SHARED_RANDOM_CLIENT_H) */
 
diff --git a/src/feature/keymgt/loadkey.h b/src/feature/keymgt/loadkey.h
index 8beee57a2..0a5af0b80 100644
--- a/src/feature/keymgt/loadkey.h
+++ b/src/feature/keymgt/loadkey.h
@@ -52,4 +52,4 @@ int read_encrypted_secret_key(ed25519_secret_key_t *out,
 int write_encrypted_secret_key(const ed25519_secret_key_t *out,
                                const char *fname);
 
-#endif
+#endif /* !defined(TOR_LOADKEY_H) */
diff --git a/src/feature/nodelist/authcert.h b/src/feature/nodelist/authcert.h
index 2effdb06e..071293f9e 100644
--- a/src/feature/nodelist/authcert.h
+++ b/src/feature/nodelist/authcert.h
@@ -57,4 +57,4 @@ MOCK_DECL(download_status_t *, download_status_for_authority_id_and_sk,
 
 void authcert_free_all(void);
 
-#endif
+#endif /* !defined(TOR_AUTHCERT_H) */
diff --git a/src/feature/nodelist/authority_cert_st.h b/src/feature/nodelist/authority_cert_st.h
index 68a84bc45..bf9b690c2 100644
--- a/src/feature/nodelist/authority_cert_st.h
+++ b/src/feature/nodelist/authority_cert_st.h
@@ -28,5 +28,5 @@ struct authority_cert_t {
   uint16_t dir_port;
 };
 
-#endif
+#endif /* !defined(AUTHORITY_CERT_ST_H) */
 
diff --git a/src/feature/nodelist/desc_store_st.h b/src/feature/nodelist/desc_store_st.h
index b04a1abc7..4d1378cdf 100644
--- a/src/feature/nodelist/desc_store_st.h
+++ b/src/feature/nodelist/desc_store_st.h
@@ -36,4 +36,4 @@ struct desc_store_t {
   size_t bytes_dropped;
 };
 
-#endif
+#endif /* !defined(DESC_STORE_ST_H) */
diff --git a/src/feature/nodelist/describe.h b/src/feature/nodelist/describe.h
index 018af6470..d29192200 100644
--- a/src/feature/nodelist/describe.h
+++ b/src/feature/nodelist/describe.h
@@ -22,4 +22,4 @@ const char *node_describe(const struct node_t *node);
 const char *router_describe(const struct routerinfo_t *ri);
 const char *routerstatus_describe(const struct routerstatus_t *ri);
 
-#endif
+#endif /* !defined(TOR_DESCRIBE_H) */
diff --git a/src/feature/nodelist/dirlist.c b/src/feature/nodelist/dirlist.c
index 93baa6e4e..e2a1d6a9f 100644
--- a/src/feature/nodelist/dirlist.c
+++ b/src/feature/nodelist/dirlist.c
@@ -28,7 +28,7 @@
 
 #include "app/config/config.h"
 #include "core/or/policies.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/authmode.h"
 #include "feature/dircommon/directory.h"
 #include "feature/nodelist/dirlist.h"
diff --git a/src/feature/nodelist/dirlist.h b/src/feature/nodelist/dirlist.h
index 9fabd0a44..b6dda32d8 100644
--- a/src/feature/nodelist/dirlist.h
+++ b/src/feature/nodelist/dirlist.h
@@ -44,4 +44,4 @@ void dir_server_add(dir_server_t *ent);
 void clear_dir_servers(void);
 void dirlist_free_all(void);
 
-#endif
+#endif /* !defined(TOR_DIRLIST_H) */
diff --git a/src/feature/nodelist/document_signature_st.h b/src/feature/nodelist/document_signature_st.h
index 66e32c422..ac2a80325 100644
--- a/src/feature/nodelist/document_signature_st.h
+++ b/src/feature/nodelist/document_signature_st.h
@@ -25,5 +25,5 @@ struct document_signature_t {
                                      * as good. */
 };
 
-#endif
+#endif /* !defined(DOCUMENT_SIGNATURE_ST_H) */
 
diff --git a/src/feature/nodelist/extrainfo_st.h b/src/feature/nodelist/extrainfo_st.h
index c54277b05..22c708f01 100644
--- a/src/feature/nodelist/extrainfo_st.h
+++ b/src/feature/nodelist/extrainfo_st.h
@@ -26,5 +26,5 @@ struct extrainfo_t {
   size_t pending_sig_len;
 };
 
-#endif
+#endif /* !defined(EXTRAINFO_ST_H) */
 
diff --git a/src/feature/nodelist/fmt_routerstatus.c b/src/feature/nodelist/fmt_routerstatus.c
index 8c9212e05..fea7cf4c6 100644
--- a/src/feature/nodelist/fmt_routerstatus.c
+++ b/src/feature/nodelist/fmt_routerstatus.c
@@ -14,55 +14,14 @@
 #include "core/or/or.h"
 #include "feature/nodelist/fmt_routerstatus.h"
 
-/* #include "lib/container/buffers.h" */
-/* #include "app/config/config.h" */
-/* #include "app/config/confparse.h" */
-/* #include "core/or/channel.h" */
-/* #include "core/or/channeltls.h" */
-/* #include "core/or/command.h" */
-/* #include "core/mainloop/connection.h" */
-/* #include "core/or/connection_or.h" */
-/* #include "feature/dircache/conscache.h" */
-/* #include "feature/dircache/consdiffmgr.h" */
-/* #include "feature/control/control.h" */
-/* #include "feature/dircache/directory.h" */
-/* #include "feature/dircache/dirserv.h" */
-/* #include "feature/hibernate/hibernate.h" */
-/* #include "feature/dirauth/keypin.h" */
-/* #include "core/mainloop/mainloop.h" */
-/* #include "feature/nodelist/microdesc.h" */
-/* #include "feature/nodelist/networkstatus.h" */
-/* #include "feature/nodelist/nodelist.h" */
 #include "core/or/policies.h"
-/* #include "core/or/protover.h" */
-/* #include "feature/stats/rephist.h" */
-/* #include "feature/relay/router.h" */
-/* #include "feature/nodelist/dirlist.h" */
 #include "feature/nodelist/routerlist.h"
-
-/* #include "feature/nodelist/routerparse.h" */
-/* #include "feature/nodelist/routerset.h" */
-/* #include "feature/nodelist/torcert.h" */
-/* #include "feature/dircommon/voting_schedule.h" */
-
 #include "feature/dirauth/dirvote.h"
 
-/* #include "feature/dircache/cached_dir_st.h" */
-/* #include "feature/dircommon/dir_connection_st.h" */
-/* #include "feature/nodelist/extrainfo_st.h" */
-/* #include "feature/nodelist/microdesc_st.h" */
-/* #include "feature/nodelist/node_st.h" */
 #include "feature/nodelist/routerinfo_st.h"
-/* #include "feature/nodelist/routerlist_st.h" */
-/* #include "core/or/tor_version_st.h" */
 #include "feature/nodelist/vote_routerstatus_st.h"
 
-/* #include "lib/compress/compress.h" */
-/* #include "lib/container/order.h" */
 #include "lib/crypt_ops/crypto_format.h"
-/* #include "lib/encoding/confline.h" */
-
-/* #include "lib/encoding/keyval.h" */
 
 /** Helper: write the router-status information in <b>rs</b> into a newly
  * allocated character buffer.  Use the same format as in network-status
@@ -233,7 +192,7 @@ routerstatus_format_entry(const routerstatus_t *rs, const char *version,
     }
 
     if (format == NS_V3_VOTE && vrs) {
-      if (tor_mem_is_zero((char*)vrs->ed25519_id, ED25519_PUBKEY_LEN)) {
+      if (fast_mem_is_zero((char*)vrs->ed25519_id, ED25519_PUBKEY_LEN)) {
         smartlist_add_strdup(chunks, "id ed25519 none\n");
       } else {
         char ed_b64[BASE64_DIGEST256_LEN+1];
diff --git a/src/feature/nodelist/microdesc.c b/src/feature/nodelist/microdesc.c
index 36922561a..89ac0a2f8 100644
--- a/src/feature/nodelist/microdesc.c
+++ b/src/feature/nodelist/microdesc.c
@@ -536,8 +536,8 @@ microdesc_cache_reload(microdesc_cache_t *cache)
   journal_content = read_file_to_str(cache->journal_fname,
                                      RFTS_IGNORE_MISSING, &st);
   if (journal_content) {
-    cache->journal_len = (size_t) st.st_size;
-    warn_if_nul_found(journal_content, cache->journal_len, 0,
+    cache->journal_len = strlen(journal_content);
+    warn_if_nul_found(journal_content, (size_t)st.st_size, 0,
                       "reading microdesc journal");
     added = microdescs_add_to_cache(cache, journal_content,
                                     journal_content+st.st_size,
@@ -970,7 +970,7 @@ microdesc_list_missing_digest256(networkstatus_t *ns, microdesc_cache_t *cache,
       continue;
     if (skip && digest256map_get(skip, (const uint8_t*)rs->descriptor_digest))
       continue;
-    if (tor_mem_is_zero(rs->descriptor_digest, DIGEST256_LEN))
+    if (fast_mem_is_zero(rs->descriptor_digest, DIGEST256_LEN))
       continue;
     /* XXXX Also skip if we're a noncache and wouldn't use this router.
      * XXXX NM Microdesc
diff --git a/src/feature/nodelist/microdesc_st.h b/src/feature/nodelist/microdesc_st.h
index 367e6a3ef..c8265cb77 100644
--- a/src/feature/nodelist/microdesc_st.h
+++ b/src/feature/nodelist/microdesc_st.h
@@ -78,4 +78,4 @@ struct microdesc_t {
   struct short_policy_t *ipv6_exit_policy;
 };
 
-#endif
+#endif /* !defined(MICRODESC_ST_H) */
diff --git a/src/feature/nodelist/networkstatus.c b/src/feature/nodelist/networkstatus.c
index 24e3b212f..2db293a8a 100644
--- a/src/feature/nodelist/networkstatus.c
+++ b/src/feature/nodelist/networkstatus.c
@@ -58,7 +58,7 @@
 #include "feature/client/bridges.h"
 #include "feature/client/entrynodes.h"
 #include "feature/client/transports.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/reachability.h"
 #include "feature/dircache/consdiffmgr.h"
 #include "feature/dircache/dirserv.h"
@@ -82,6 +82,7 @@
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/crypt_ops/crypto_util.h"
 
+#include "feature/dirauth/dirauth_periodic.h"
 #include "feature/dirauth/dirvote.h"
 #include "feature/dirauth/authmode.h"
 #include "feature/dirauth/shared_random.h"
@@ -1771,7 +1772,7 @@ reload_consensus_from_file(const char *fname,
                                              flavor, flags, source_dir);
     tor_free(content);
   }
-#endif
+#endif /* defined(_WIN32) */
   if (rv < -1) {
     log_warn(LD_GENERAL, "Couldn't set consensus from cache file %s",
              escaped(fname));
@@ -2365,6 +2366,49 @@ networkstatus_getinfo_helper_single(const routerstatus_t *rs)
                                    NULL);
 }
 
+/**
+ * Extract status information from <b>ri</b> and from other authority
+ * functions and store it in <b>rs</b>. <b>rs</b> is zeroed out before it is
+ * set.
+ *
+ * We assume that node-\>is_running has already been set, e.g. by
+ *   dirserv_set_router_is_running(ri, now);
+ */
+void
+set_routerstatus_from_routerinfo(routerstatus_t *rs,
+                                 const node_t *node,
+                                 const routerinfo_t *ri)
+{
+  memset(rs, 0, sizeof(routerstatus_t));
+
+  rs->is_authority =
+    router_digest_is_trusted_dir(ri->cache_info.identity_digest);
+
+  /* Set by compute_performance_thresholds or from consensus */
+  rs->is_exit = node->is_exit;
+  rs->is_stable = node->is_stable;
+  rs->is_fast = node->is_fast;
+  rs->is_flagged_running = node->is_running;
+  rs->is_valid = node->is_valid;
+  rs->is_possible_guard = node->is_possible_guard;
+  rs->is_bad_exit = node->is_bad_exit;
+  rs->is_hs_dir = node->is_hs_dir;
+  rs->is_named = rs->is_unnamed = 0;
+
+  rs->published_on = ri->cache_info.published_on;
+  memcpy(rs->identity_digest, node->identity, DIGEST_LEN);
+  memcpy(rs->descriptor_digest, ri->cache_info.signed_descriptor_digest,
+         DIGEST_LEN);
+  rs->addr = ri->addr;
+  strlcpy(rs->nickname, ri->nickname, sizeof(rs->nickname));
+  rs->or_port = ri->or_port;
+  rs->dir_port = ri->dir_port;
+  rs->is_v2_dir = ri->supports_tunnelled_dir_requests;
+
+  tor_addr_copy(&rs->ipv6_addr, &ri->ipv6_addr);
+  rs->ipv6_orport = ri->ipv6_orport;
+}
+
 /** Alloc and return a string describing routerstatuses for the most
  * recent info of each router we know about that is of purpose
  * <b>purpose_string</b>. Return NULL if unrecognized purpose.
@@ -2381,7 +2425,6 @@ networkstatus_getinfo_by_purpose(const char *purpose_string, time_t now)
   smartlist_t *statuses;
   const uint8_t purpose = router_purpose_from_string(purpose_string);
   routerstatus_t rs;
-  const int bridge_auth = authdir_mode_bridge(get_options());
 
   if (purpose == ROUTER_PURPOSE_UNKNOWN) {
     log_info(LD_DIR, "Unrecognized purpose '%s' when listing router statuses.",
@@ -2398,11 +2441,7 @@ networkstatus_getinfo_by_purpose(const char *purpose_string, time_t now)
       continue;
     if (ri->purpose != purpose)
       continue;
-    /* TODO: modifying the running flag in a getinfo is a bad idea */
-    if (bridge_auth && ri->purpose == ROUTER_PURPOSE_BRIDGE)
-      dirserv_set_router_is_running(ri, now);
-    /* then generate and write out status lines for each of them */
-    set_routerstatus_from_routerinfo(&rs, node, ri, now, 0);
+    set_routerstatus_from_routerinfo(&rs, node, ri);
     smartlist_add(statuses, networkstatus_getinfo_helper_single(&rs));
   } SMARTLIST_FOREACH_END(ri);
 
@@ -2412,43 +2451,6 @@ networkstatus_getinfo_by_purpose(const char *purpose_string, time_t now)
   return answer;
 }
 
-/** Write out router status entries for all our bridge descriptors. */
-void
-networkstatus_dump_bridge_status_to_file(time_t now)
-{
-  char *status = networkstatus_getinfo_by_purpose("bridge", now);
-  char *fname = NULL;
-  char *thresholds = NULL;
-  char *published_thresholds_and_status = NULL;
-  char published[ISO_TIME_LEN+1];
-  const routerinfo_t *me = router_get_my_routerinfo();
-  char fingerprint[FINGERPRINT_LEN+1];
-  char *fingerprint_line = NULL;
-
-  if (me && crypto_pk_get_fingerprint(me->identity_pkey,
-                                      fingerprint, 0) >= 0) {
-    tor_asprintf(&fingerprint_line, "fingerprint %s\n", fingerprint);
-  } else {
-    log_warn(LD_BUG, "Error computing fingerprint for bridge status.");
-  }
-  format_iso_time(published, now);
-  dirserv_compute_bridge_flag_thresholds();
-  thresholds = dirserv_get_flag_thresholds_line();
-  tor_asprintf(&published_thresholds_and_status,
-               "published %s\nflag-thresholds %s\n%s%s",
-               published, thresholds, fingerprint_line ? fingerprint_line : "",
-               status);
-  fname = get_datadir_fname("networkstatus-bridges");
-  if (write_str_to_file(fname,published_thresholds_and_status,0)<0) {
-    log_warn(LD_DIRSERV, "Unable to write networkstatus-bridges file.");
-  }
-  tor_free(thresholds);
-  tor_free(published_thresholds_and_status);
-  tor_free(fname);
-  tor_free(status);
-  tor_free(fingerprint_line);
-}
-
 /* DOCDOC get_net_param_from_list */
 static int32_t
 get_net_param_from_list(smartlist_t *net_params, const char *param_name,
diff --git a/src/feature/nodelist/networkstatus.h b/src/feature/nodelist/networkstatus.h
index 8269fc618..600fd7fbd 100644
--- a/src/feature/nodelist/networkstatus.h
+++ b/src/feature/nodelist/networkstatus.h
@@ -122,7 +122,6 @@ void signed_descs_update_status_from_consensus_networkstatus(
 
 char *networkstatus_getinfo_helper_single(const routerstatus_t *rs);
 char *networkstatus_getinfo_by_purpose(const char *purpose_string, time_t now);
-void networkstatus_dump_bridge_status_to_file(time_t now);
 MOCK_DECL(int32_t, networkstatus_get_param,
           (const networkstatus_t *ns, const char *param_name,
            int32_t default_val, int32_t min_val, int32_t max_val));
@@ -149,6 +148,10 @@ void vote_routerstatus_free_(vote_routerstatus_t *rs);
 #define vote_routerstatus_free(rs) \
   FREE_AND_NULL(vote_routerstatus_t, vote_routerstatus_free_, (rs))
 
+void set_routerstatus_from_routerinfo(routerstatus_t *rs,
+                                      const node_t *node,
+                                      const routerinfo_t *ri);
+
 #ifdef NETWORKSTATUS_PRIVATE
 #ifdef TOR_UNIT_TESTS
 STATIC int networkstatus_set_current_consensus_from_ns(networkstatus_t *c,
diff --git a/src/feature/nodelist/networkstatus_sr_info_st.h b/src/feature/nodelist/networkstatus_sr_info_st.h
index 677d8ed81..420c3d61e 100644
--- a/src/feature/nodelist/networkstatus_sr_info_st.h
+++ b/src/feature/nodelist/networkstatus_sr_info_st.h
@@ -19,5 +19,5 @@ struct networkstatus_sr_info_t {
   smartlist_t *commits;
 };
 
-#endif
+#endif /* !defined(NETWORKSTATUS_SR_INFO_ST_H) */
 
diff --git a/src/feature/nodelist/networkstatus_st.h b/src/feature/nodelist/networkstatus_st.h
index 5c1eea325..6e84c170d 100644
--- a/src/feature/nodelist/networkstatus_st.h
+++ b/src/feature/nodelist/networkstatus_st.h
@@ -104,4 +104,4 @@ struct networkstatus_t {
   uint8_t bw_file_digest256[DIGEST256_LEN];
 };
 
-#endif
+#endif /* !defined(NETWORKSTATUS_ST_H) */
diff --git a/src/feature/nodelist/networkstatus_voter_info_st.h b/src/feature/nodelist/networkstatus_voter_info_st.h
index 4037fcdec..66af82a8e 100644
--- a/src/feature/nodelist/networkstatus_voter_info_st.h
+++ b/src/feature/nodelist/networkstatus_voter_info_st.h
@@ -27,4 +27,4 @@ struct networkstatus_voter_info_t {
   smartlist_t *sigs;
 };
 
-#endif
+#endif /* !defined(NETWORKSTATUS_VOTER_INFO_ST_H) */
diff --git a/src/feature/nodelist/nickname.h b/src/feature/nodelist/nickname.h
index 9bdc6b50e..78db2a5f9 100644
--- a/src/feature/nodelist/nickname.h
+++ b/src/feature/nodelist/nickname.h
@@ -16,4 +16,4 @@ int is_legal_nickname(const char *s);
 int is_legal_nickname_or_hexdigest(const char *s);
 int is_legal_hexdigest(const char *s);
 
-#endif
+#endif /* !defined(TOR_NICKNAME_H) */
diff --git a/src/feature/nodelist/node_select.c b/src/feature/nodelist/node_select.c
index e31abb247..719b4b1b2 100644
--- a/src/feature/nodelist/node_select.c
+++ b/src/feature/nodelist/node_select.c
@@ -30,6 +30,7 @@
 #include "feature/nodelist/routerset.h"
 #include "feature/relay/router.h"
 #include "feature/relay/routermode.h"
+#include "lib/container/bitarray.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/math/fp.h"
 
@@ -585,6 +586,7 @@ compute_weighted_bandwidths(const smartlist_t *sl,
   }
 
   weight_scale = networkstatus_get_weight_scale_param(NULL);
+  tor_assert(weight_scale >= 1);
 
   if (rule == WEIGHT_FOR_GUARD) {
     Wg = networkstatus_get_bw_weight(NULL, "Wgg", -1);
@@ -825,6 +827,58 @@ routerlist_add_node_and_family(smartlist_t *sl, const routerinfo_t *router)
   nodelist_add_node_and_family(sl, node);
 }
 
+/**
+ * Remove every node_t that appears in <b>excluded</b> from <b>sl</b>.
+ *
+ * Behaves like smartlist_subtract, but uses nodelist_idx values to deliver
+ * linear performance when smartlist_subtract would be quadratic.
+ **/
+static void
+nodelist_subtract(smartlist_t *sl, const smartlist_t *excluded)
+{
+  const smartlist_t *nodelist = nodelist_get_list();
+  const int nodelist_len = smartlist_len(nodelist);
+  bitarray_t *excluded_idx = bitarray_init_zero(nodelist_len);
+
+  /* We haven't used nodelist_idx in this way previously, so I'm going to be
+   * paranoid in this code, and check that nodelist_idx is correct for every
+   * node before we use it.  If we fail, we fall back to smartlist_subtract().
+   */
+
+  /* Set the excluded_idx bit corresponding to every excluded node...
+   */
+  SMARTLIST_FOREACH_BEGIN(excluded, const node_t *, node) {
+    const int idx = node->nodelist_idx;
+    if (BUG(idx < 0) || BUG(idx >= nodelist_len) ||
+        BUG(node != smartlist_get(nodelist, idx))) {
+      goto internal_error;
+    }
+    bitarray_set(excluded_idx, idx);
+  } SMARTLIST_FOREACH_END(node);
+
+  /* Then remove them from sl.
+   */
+  SMARTLIST_FOREACH_BEGIN(sl, const node_t *, node) {
+    const int idx = node->nodelist_idx;
+    if (BUG(idx < 0) || BUG(idx >= nodelist_len) ||
+        BUG(node != smartlist_get(nodelist, idx))) {
+      goto internal_error;
+    }
+    if (bitarray_is_set(excluded_idx, idx)) {
+      SMARTLIST_DEL_CURRENT(sl, node);
+    }
+  } SMARTLIST_FOREACH_END(node);
+
+  bitarray_free(excluded_idx);
+  return;
+
+ internal_error:
+  log_warn(LD_BUG, "Internal error prevented us from using the fast method "
+           "for subtracting nodelists. Falling back to the quadratic way.");
+  smartlist_subtract(sl, excluded);
+  bitarray_free(excluded_idx);
+}
+
 /** Return a random running node from the nodelist. Never
  * pick a node that is in
  * <b>excludedsmartlist</b>, or which matches <b>excludedset</b>,
@@ -859,6 +913,7 @@ router_choose_random_node(smartlist_t *excludedsmartlist,
   const int direct_conn = (flags & CRN_DIRECT_CONN) != 0;
   const int rendezvous_v3 = (flags & CRN_RENDEZVOUS_V3) != 0;
 
+  const smartlist_t *node_list = nodelist_get_list();
   smartlist_t *sl=smartlist_new(),
     *excludednodes=smartlist_new();
   const node_t *choice = NULL;
@@ -869,17 +924,17 @@ router_choose_random_node(smartlist_t *excludedsmartlist,
   rule = weight_for_exit ? WEIGHT_FOR_EXIT :
     (need_guard ? WEIGHT_FOR_GUARD : WEIGHT_FOR_MID);
 
-  SMARTLIST_FOREACH_BEGIN(nodelist_get_list(), node_t *, node) {
+  SMARTLIST_FOREACH_BEGIN(node_list, const node_t *, node) {
     if (node_allows_single_hop_exits(node)) {
       /* Exclude relays that allow single hop exit circuits. This is an
        * obsolete option since 0.2.9.2-alpha and done by default in
        * 0.3.1.0-alpha. */
-      smartlist_add(excludednodes, node);
+      smartlist_add(excludednodes, (node_t*)node);
     } else if (rendezvous_v3 &&
                !node_supports_v3_rendezvous_point(node)) {
       /* Exclude relays that do not support to rendezvous for a hidden service
        * version 3. */
-      smartlist_add(excludednodes, node);
+      smartlist_add(excludednodes, (node_t*)node);
     }
   } SMARTLIST_FOREACH_END(node);
 
@@ -896,19 +951,11 @@ router_choose_random_node(smartlist_t *excludedsmartlist,
            "We found %d running nodes.",
             smartlist_len(sl));
 
-  smartlist_subtract(sl,excludednodes);
-  log_debug(LD_CIRC,
-            "We removed %d excludednodes, leaving %d nodes.",
-            smartlist_len(excludednodes),
-            smartlist_len(sl));
-
   if (excludedsmartlist) {
-    smartlist_subtract(sl,excludedsmartlist);
-    log_debug(LD_CIRC,
-              "We removed %d excludedsmartlist, leaving %d nodes.",
-              smartlist_len(excludedsmartlist),
-              smartlist_len(sl));
+    smartlist_add_all(excludednodes, excludedsmartlist);
   }
+  nodelist_subtract(sl, excludednodes);
+
   if (excludedset) {
     routerset_subtract_nodes(sl,excludedset);
     log_debug(LD_CIRC,
diff --git a/src/feature/nodelist/node_select.h b/src/feature/nodelist/node_select.h
index ed7450b92..d8b4aca5c 100644
--- a/src/feature/nodelist/node_select.h
+++ b/src/feature/nodelist/node_select.h
@@ -97,6 +97,6 @@ STATIC const routerstatus_t *router_pick_directory_server_impl(
                                            int *n_busy_out);
 STATIC int router_is_already_dir_fetching(const tor_addr_port_t *ap,
                                           int serverdesc, int microdesc);
-#endif
+#endif /* defined(NODE_SELECT_PRIVATE) */
 
-#endif
+#endif /* !defined(TOR_NODE_SELECT_H) */
diff --git a/src/feature/nodelist/node_st.h b/src/feature/nodelist/node_st.h
index 53ffde29e..c63a535a1 100644
--- a/src/feature/nodelist/node_st.h
+++ b/src/feature/nodelist/node_st.h
@@ -99,4 +99,4 @@ struct node_t {
   struct hsdir_index_t hsdir_index;
 };
 
-#endif
+#endif /* !defined(NODE_ST_H) */
diff --git a/src/feature/nodelist/nodefamily.h b/src/feature/nodelist/nodefamily.h
index bc5dafce0..31b71e77a 100644
--- a/src/feature/nodelist/nodefamily.h
+++ b/src/feature/nodelist/nodefamily.h
@@ -47,4 +47,4 @@ char *nodefamily_canonicalize(const char *s, const uint8_t *rsa_id_self,
 
 void nodefamily_free_all(void);
 
-#endif
+#endif /* !defined(TOR_NODEFAMILY_H) */
diff --git a/src/feature/nodelist/nodefamily_st.h b/src/feature/nodelist/nodefamily_st.h
index be533da82..20390c930 100644
--- a/src/feature/nodelist/nodefamily_st.h
+++ b/src/feature/nodelist/nodefamily_st.h
@@ -45,4 +45,4 @@ struct nodefamily_t {
 #define NODEFAMILY_MEMBER_PTR(nf, i) \
   (&((nf)->family_members[(i) * NODEFAMILY_MEMBER_LEN]))
 
-#endif
+#endif /* !defined(TOR_NODEFAMILY_ST_H) */
diff --git a/src/feature/nodelist/nodelist.c b/src/feature/nodelist/nodelist.c
index 8b02dd9c6..21914c6c6 100644
--- a/src/feature/nodelist/nodelist.c
+++ b/src/feature/nodelist/nodelist.c
@@ -49,7 +49,7 @@
 #include "core/or/protover.h"
 #include "feature/client/bridges.h"
 #include "feature/client/entrynodes.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/process_descs.h"
 #include "feature/dircache/dirserv.h"
 #include "feature/hs/hs_client.h"
@@ -944,7 +944,7 @@ nodelist_ensure_freshness(networkstatus_t *ns)
 /** Return a list of a node_t * for every node we know about.  The caller
  * MUST NOT modify the list. (You can set and clear flags in the nodes if
  * you must, but you must not add or remove nodes.) */
-MOCK_IMPL(smartlist_t *,
+MOCK_IMPL(const smartlist_t *,
 nodelist_get_list,(void))
 {
   init_nodelist();
@@ -1189,6 +1189,102 @@ node_get_rsa_id_digest(const node_t *node)
   return (const uint8_t*)node->identity;
 }
 
+/* Returns a new smartlist with all possible link specifiers from node:
+ *  - legacy ID is mandatory thus MUST be present in node;
+ *  - include ed25519 link specifier if present in the node, and the node
+ *    supports ed25519 link authentication, and:
+ *    - if direct_conn is true, its link versions are compatible with us,
+ *    - if direct_conn is false, regardless of its link versions;
+ *  - include IPv4 link specifier, if the primary address is not IPv4, log a
+ *    BUG() warning, and return an empty smartlist;
+ *  - include IPv6 link specifier if present in the node.
+ *
+ * If node is NULL, returns an empty smartlist.
+ *
+ * The smartlist must be freed using link_specifier_smartlist_free(). */
+smartlist_t *
+node_get_link_specifier_smartlist(const node_t *node, bool direct_conn)
+{
+  link_specifier_t *ls;
+  tor_addr_port_t ap;
+  smartlist_t *lspecs = smartlist_new();
+
+  if (!node)
+    return lspecs;
+
+  /* Get the relay's IPv4 address. */
+  node_get_prim_orport(node, &ap);
+
+  /* We expect the node's primary address to be a valid IPv4 address.
+   * This conforms to the protocol, which requires either an IPv4 or IPv6
+   * address (or both). */
+  if (BUG(!tor_addr_is_v4(&ap.addr)) ||
+      BUG(!tor_addr_port_is_valid_ap(&ap, 0))) {
+    return lspecs;
+  }
+
+  ls = link_specifier_new();
+  link_specifier_set_ls_type(ls, LS_IPV4);
+  link_specifier_set_un_ipv4_addr(ls, tor_addr_to_ipv4h(&ap.addr));
+  link_specifier_set_un_ipv4_port(ls, ap.port);
+  /* Four bytes IPv4 and two bytes port. */
+  link_specifier_set_ls_len(ls, sizeof(ap.addr.addr.in_addr) +
+                            sizeof(ap.port));
+  smartlist_add(lspecs, ls);
+
+  /* Legacy ID is mandatory and will always be present in node. */
+  ls = link_specifier_new();
+  link_specifier_set_ls_type(ls, LS_LEGACY_ID);
+  memcpy(link_specifier_getarray_un_legacy_id(ls), node->identity,
+         link_specifier_getlen_un_legacy_id(ls));
+  link_specifier_set_ls_len(ls, link_specifier_getlen_un_legacy_id(ls));
+  smartlist_add(lspecs, ls);
+
+  /* ed25519 ID is only included if the node has it, and the node declares a
+   protocol version that supports ed25519 link authentication.
+   If direct_conn is true, we also require that the node's link version is
+   compatible with us. (Otherwise, we will be sending the ed25519 key
+   to another tor, which may support different link versions.) */
+  if (!ed25519_public_key_is_zero(&node->ed25519_id) &&
+      node_supports_ed25519_link_authentication(node, direct_conn)) {
+    ls = link_specifier_new();
+    link_specifier_set_ls_type(ls, LS_ED25519_ID);
+    memcpy(link_specifier_getarray_un_ed25519_id(ls), &node->ed25519_id,
+           link_specifier_getlen_un_ed25519_id(ls));
+    link_specifier_set_ls_len(ls, link_specifier_getlen_un_ed25519_id(ls));
+    smartlist_add(lspecs, ls);
+  }
+
+  /* Check for IPv6. If so, include it as well. */
+  if (node_has_ipv6_orport(node)) {
+    ls = link_specifier_new();
+    node_get_pref_ipv6_orport(node, &ap);
+    link_specifier_set_ls_type(ls, LS_IPV6);
+    size_t addr_len = link_specifier_getlen_un_ipv6_addr(ls);
+    const uint8_t *in6_addr = tor_addr_to_in6_addr8(&ap.addr);
+    uint8_t *ipv6_array = link_specifier_getarray_un_ipv6_addr(ls);
+    memcpy(ipv6_array, in6_addr, addr_len);
+    link_specifier_set_un_ipv6_port(ls, ap.port);
+    /* Sixteen bytes IPv6 and two bytes port. */
+    link_specifier_set_ls_len(ls, addr_len + sizeof(ap.port));
+    smartlist_add(lspecs, ls);
+  }
+
+  return lspecs;
+}
+
+/* Free a link specifier list. */
+void
+link_specifier_smartlist_free_(smartlist_t *ls_list)
+{
+  if (!ls_list)
+    return;
+
+  SMARTLIST_FOREACH(ls_list, link_specifier_t *, lspec,
+                    link_specifier_free(lspec));
+  smartlist_free(ls_list);
+}
+
 /** Return the nickname of <b>node</b>, or NULL if we can't find one. */
 const char *
 node_get_nickname(const node_t *node)
@@ -1763,7 +1859,7 @@ microdesc_has_curve25519_onion_key(const microdesc_t *md)
     return 0;
   }
 
-  if (tor_mem_is_zero((const char*)md->onion_curve25519_pkey->public_key,
+  if (fast_mem_is_zero((const char*)md->onion_curve25519_pkey->public_key,
                       CURVE25519_PUBKEY_LEN)) {
     return 0;
   }
@@ -1843,7 +1939,7 @@ node_set_country(node_t *node)
 void
 nodelist_refresh_countries(void)
 {
-  smartlist_t *nodes = nodelist_get_list();
+  const smartlist_t *nodes = nodelist_get_list();
   SMARTLIST_FOREACH(nodes, node_t *, node,
                     node_set_country(node));
 }
diff --git a/src/feature/nodelist/nodelist.h b/src/feature/nodelist/nodelist.h
index 342095961..84ab5f7a5 100644
--- a/src/feature/nodelist/nodelist.h
+++ b/src/feature/nodelist/nodelist.h
@@ -77,6 +77,11 @@ int node_supports_v3_hsdir(const node_t *node);
 int node_supports_ed25519_hs_intro(const node_t *node);
 int node_supports_v3_rendezvous_point(const node_t *node);
 const uint8_t *node_get_rsa_id_digest(const node_t *node);
+smartlist_t *node_get_link_specifier_smartlist(const node_t *node,
+                                               bool direct_conn);
+void link_specifier_smartlist_free_(smartlist_t *ls_list);
+#define link_specifier_smartlist_free(ls_list) \
+  FREE_AND_NULL(smartlist_t, link_specifier_smartlist_free_, (ls_list))
 
 int node_has_ipv6_addr(const node_t *node);
 int node_has_ipv6_orport(const node_t *node);
@@ -96,7 +101,7 @@ const struct curve25519_public_key_t *node_get_curve25519_onion_key(
                                   const node_t *node);
 crypto_pk_t *node_get_rsa_onion_key(const node_t *node);
 
-MOCK_DECL(smartlist_t *, nodelist_get_list, (void));
+MOCK_DECL(const smartlist_t *, nodelist_get_list, (void));
 
 /* Temporary during transition to multiple addresses.  */
 void node_get_addr(const node_t *node, tor_addr_t *addr_out);
diff --git a/src/feature/nodelist/routerinfo.h b/src/feature/nodelist/routerinfo.h
index bfa28c775..ca66e660b 100644
--- a/src/feature/nodelist/routerinfo.h
+++ b/src/feature/nodelist/routerinfo.h
@@ -24,4 +24,4 @@ smartlist_t *router_get_all_orports(const routerinfo_t *ri);
 const char *router_purpose_to_string(uint8_t p);
 uint8_t router_purpose_from_string(const char *s);
 
-#endif
+#endif /* !defined(TOR_ROUTERINFO_H) */
diff --git a/src/feature/nodelist/routerinfo_st.h b/src/feature/nodelist/routerinfo_st.h
index 59656818c..59fd56d0a 100644
--- a/src/feature/nodelist/routerinfo_st.h
+++ b/src/feature/nodelist/routerinfo_st.h
@@ -112,4 +112,4 @@ struct routerinfo_t {
   uint8_t purpose;
 };
 
-#endif
+#endif /* !defined(ROUTERINFO_ST_H) */
diff --git a/src/feature/nodelist/routerlist.c b/src/feature/nodelist/routerlist.c
index d1220f553..c56b714cb 100644
--- a/src/feature/nodelist/routerlist.c
+++ b/src/feature/nodelist/routerlist.c
@@ -67,7 +67,7 @@
 #include "core/mainloop/mainloop.h"
 #include "core/or/policies.h"
 #include "feature/client/bridges.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/authmode.h"
 #include "feature/dirauth/process_descs.h"
 #include "feature/dirauth/reachability.h"
@@ -954,20 +954,18 @@ routerlist_free_(routerlist_t *rl)
   smartlist_free(rl->routers);
   smartlist_free(rl->old_routers);
   if (rl->desc_store.mmap) {
-    int res = tor_munmap_file(routerlist->desc_store.mmap);
+    int res = tor_munmap_file(rl->desc_store.mmap);
     if (res != 0) {
       log_warn(LD_FS, "Failed to munmap routerlist->desc_store.mmap");
     }
   }
   if (rl->extrainfo_store.mmap) {
-    int res = tor_munmap_file(routerlist->extrainfo_store.mmap);
+    int res = tor_munmap_file(rl->extrainfo_store.mmap);
     if (res != 0) {
       log_warn(LD_FS, "Failed to munmap routerlist->extrainfo_store.mmap");
     }
   }
   tor_free(rl);
-
-  router_dir_info_changed();
 }
 
 /** Log information about how much memory is being used for routerlist,
@@ -1426,8 +1424,10 @@ routerlist_reparse_old(routerlist_t *rl, signed_descriptor_t *sd)
 void
 routerlist_free_all(void)
 {
-  routerlist_free(routerlist);
-  routerlist = NULL;
+  routerlist_t *rl = routerlist;
+  routerlist = NULL; // Prevent internals of routerlist_free() from using
+                     // routerlist.
+  routerlist_free(rl);
   dirlist_free_all();
   if (warned_nicknames) {
     SMARTLIST_FOREACH(warned_nicknames, char *, cp, tor_free(cp));
@@ -1926,6 +1926,8 @@ routerlist_remove_old_routers(void)
 void
 routerlist_descriptors_added(smartlist_t *sl, int from_cache)
 {
+  // XXXX use pubsub mechanism here.
+
   tor_assert(sl);
   control_event_descriptors_changed(sl);
   SMARTLIST_FOREACH_BEGIN(sl, routerinfo_t *, ri) {
@@ -1933,7 +1935,9 @@ routerlist_descriptors_added(smartlist_t *sl, int from_cache)
       learned_bridge_descriptor(ri, from_cache);
     if (ri->needs_retest_if_added) {
       ri->needs_retest_if_added = 0;
+#ifdef HAVE_MODULE_DIRAUTH
       dirserv_single_reachability_test(approx_time(), ri);
+#endif
     }
   } SMARTLIST_FOREACH_END(ri);
 }
@@ -2856,7 +2860,7 @@ int
 router_differences_are_cosmetic(const routerinfo_t *r1, const routerinfo_t *r2)
 {
   time_t r1pub, r2pub;
-  long time_difference;
+  time_t time_difference;
   tor_assert(r1 && r2);
 
   /* r1 should be the one that was published first. */
@@ -2920,7 +2924,9 @@ router_differences_are_cosmetic(const routerinfo_t *r1, const routerinfo_t *r2)
    * give or take some slop? */
   r1pub = r1->cache_info.published_on;
   r2pub = r2->cache_info.published_on;
-  time_difference = labs(r2->uptime - (r1->uptime + (r2pub - r1pub)));
+  time_difference = r2->uptime - (r1->uptime + (r2pub - r1pub));
+  if (time_difference < 0)
+    time_difference = - time_difference;
   if (time_difference > ROUTER_ALLOW_UPTIME_DRIFT &&
       time_difference > r1->uptime * .05 &&
       time_difference > r2->uptime * .05)
@@ -2969,7 +2975,7 @@ routerinfo_incompatible_with_extrainfo(const crypto_pk_t *identity_pkey,
   digest256_matches = tor_memeq(ei->digest256,
                                 sd->extra_info_digest256, DIGEST256_LEN);
   digest256_matches |=
-    tor_mem_is_zero(sd->extra_info_digest256, DIGEST256_LEN);
+    fast_mem_is_zero(sd->extra_info_digest256, DIGEST256_LEN);
 
   /* The identity must match exactly to have been generated at the same time
    * by the same router. */
@@ -3053,7 +3059,7 @@ routerinfo_has_curve25519_onion_key(const routerinfo_t *ri)
     return 0;
   }
 
-  if (tor_mem_is_zero((const char*)ri->onion_curve25519_pkey->public_key,
+  if (fast_mem_is_zero((const char*)ri->onion_curve25519_pkey->public_key,
                       CURVE25519_PUBKEY_LEN)) {
     return 0;
   }
diff --git a/src/feature/nodelist/routerlist_st.h b/src/feature/nodelist/routerlist_st.h
index 7446ead3c..10b919a1b 100644
--- a/src/feature/nodelist/routerlist_st.h
+++ b/src/feature/nodelist/routerlist_st.h
@@ -36,5 +36,5 @@ struct routerlist_t {
   desc_store_t extrainfo_store;
 };
 
-#endif
+#endif /* !defined(ROUTERLIST_ST_H) */
 
diff --git a/src/feature/nodelist/routerset.c b/src/feature/nodelist/routerset.c
index 55e275695..e801fd81b 100644
--- a/src/feature/nodelist/routerset.c
+++ b/src/feature/nodelist/routerset.c
@@ -378,7 +378,7 @@ routerset_get_all_nodes(smartlist_t *out, const routerset_t *routerset,
   } else {
     /* We need to iterate over the routerlist to get all the ones of the
      * right kind. */
-    smartlist_t *nodes = nodelist_get_list();
+    const smartlist_t *nodes = nodelist_get_list();
     SMARTLIST_FOREACH(nodes, const node_t *, node, {
         if (running_only && !node->is_running)
           continue;
diff --git a/src/feature/nodelist/routerstatus_st.h b/src/feature/nodelist/routerstatus_st.h
index 8d91b45e1..46337c9e5 100644
--- a/src/feature/nodelist/routerstatus_st.h
+++ b/src/feature/nodelist/routerstatus_st.h
@@ -78,5 +78,5 @@ struct routerstatus_t {
 
 };
 
-#endif
+#endif /* !defined(ROUTERSTATUS_ST_H) */
 
diff --git a/src/feature/nodelist/signed_descriptor_st.h b/src/feature/nodelist/signed_descriptor_st.h
index bdcebf184..64c28f744 100644
--- a/src/feature/nodelist/signed_descriptor_st.h
+++ b/src/feature/nodelist/signed_descriptor_st.h
@@ -57,5 +57,5 @@ struct signed_descriptor_t {
   unsigned int send_unencrypted : 1;
 };
 
-#endif
+#endif /* !defined(SIGNED_DESCRIPTOR_ST_H) */
 
diff --git a/src/feature/nodelist/torcert.c b/src/feature/nodelist/torcert.c
index b0197e9f1..270c14eb1 100644
--- a/src/feature/nodelist/torcert.c
+++ b/src/feature/nodelist/torcert.c
@@ -74,7 +74,7 @@ tor_cert_sign_impl(const ed25519_keypair_t *signing_key,
   tor_assert(real_len == alloc_len);
   tor_assert(real_len > ED25519_SIG_LEN);
   uint8_t *sig = encoded + (real_len - ED25519_SIG_LEN);
-  tor_assert(tor_mem_is_zero((char*)sig, ED25519_SIG_LEN));
+  tor_assert(fast_mem_is_zero((char*)sig, ED25519_SIG_LEN));
 
   ed25519_signature_t signature;
   if (ed25519_sign(&signature, encoded,
@@ -290,8 +290,8 @@ tor_cert_describe_signature_status(const tor_cert_t *cert)
 }
 
 /** Return a new copy of <b>cert</b> */
-tor_cert_t *
-tor_cert_dup(const tor_cert_t *cert)
+MOCK_IMPL(tor_cert_t *,
+tor_cert_dup,(const tor_cert_t *cert))
 {
   tor_cert_t *newcert = tor_memdup(cert, sizeof(tor_cert_t));
   if (cert->encoded)
diff --git a/src/feature/nodelist/torcert.h b/src/feature/nodelist/torcert.h
index 492275b51..03d5bdca9 100644
--- a/src/feature/nodelist/torcert.h
+++ b/src/feature/nodelist/torcert.h
@@ -71,7 +71,7 @@ int tor_cert_checksig(tor_cert_t *cert,
                       const ed25519_public_key_t *pubkey, time_t now);
 const char *tor_cert_describe_signature_status(const tor_cert_t *cert);
 
-tor_cert_t *tor_cert_dup(const tor_cert_t *cert);
+MOCK_DECL(tor_cert_t *,tor_cert_dup,(const tor_cert_t *cert));
 int tor_cert_eq(const tor_cert_t *cert1, const tor_cert_t *cert2);
 int tor_cert_opt_eq(const tor_cert_t *cert1, const tor_cert_t *cert2);
 
diff --git a/src/feature/nodelist/vote_routerstatus_st.h b/src/feature/nodelist/vote_routerstatus_st.h
index 366754c16..0d909da26 100644
--- a/src/feature/nodelist/vote_routerstatus_st.h
+++ b/src/feature/nodelist/vote_routerstatus_st.h
@@ -38,4 +38,4 @@ struct vote_routerstatus_t {
   uint8_t ed25519_id[ED25519_PUBKEY_LEN];
 };
 
-#endif
+#endif /* !defined(VOTE_ROUTERSTATUS_ST_H) */
diff --git a/src/feature/relay/dns.c b/src/feature/relay/dns.c
index fa0a1b591..05b97e0ae 100644
--- a/src/feature/relay/dns.c
+++ b/src/feature/relay/dns.c
@@ -59,7 +59,7 @@
 #include "core/or/connection_edge.h"
 #include "core/or/policies.h"
 #include "core/or/relay.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/relay/dns.h"
 #include "feature/relay/router.h"
 #include "feature/relay/routermode.h"
@@ -1394,7 +1394,7 @@ configured_nameserver_address(const size_t idx)
 
  return NULL;
 }
-#endif
+#endif /* defined(HAVE_EVDNS_BASE_GET_NAMESERVER_ADDR) */
 
 /** Configure eventdns nameservers if force is true, or if the configuration
  * has changed since the last time we called this function, or if we failed on
@@ -2187,7 +2187,8 @@ dns_cache_handle_oom(time_t now, size_t min_remove_bytes)
     current_size -= bytes_removed;
     total_bytes_removed += bytes_removed;
 
-    time_inc += 3600; /* Increase time_inc by 1 hour. */
+    /* Increase time_inc by a reasonable fraction. */
+    time_inc += (MAX_DNS_TTL_AT_EXIT / 4);
   } while (total_bytes_removed < min_remove_bytes);
 
   return total_bytes_removed;
diff --git a/src/feature/relay/ext_orport.c b/src/feature/relay/ext_orport.c
index 8589efb48..c343d19b8 100644
--- a/src/feature/relay/ext_orport.c
+++ b/src/feature/relay/ext_orport.c
@@ -20,7 +20,7 @@
 #include "core/or/or.h"
 #include "core/mainloop/connection.h"
 #include "core/or/connection_or.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "app/config/config.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/crypt_ops/crypto_util.h"
@@ -659,4 +659,3 @@ ext_orport_free_all(void)
   if (ext_or_auth_cookie) /* Free the auth cookie */
     tor_free(ext_or_auth_cookie);
 }
-
diff --git a/src/feature/relay/onion_queue.c b/src/feature/relay/onion_queue.c
index 696905cf5..c37745cf3 100644
--- a/src/feature/relay/onion_queue.c
+++ b/src/feature/relay/onion_queue.c
@@ -212,10 +212,12 @@ num_ntors_per_tap(void)
 #define MIN_NUM_NTORS_PER_TAP 1
 #define MAX_NUM_NTORS_PER_TAP 100000
 
-  return networkstatus_get_param(NULL, "NumNTorsPerTAP",
-                                 DEFAULT_NUM_NTORS_PER_TAP,
-                                 MIN_NUM_NTORS_PER_TAP,
-                                 MAX_NUM_NTORS_PER_TAP);
+  int result = networkstatus_get_param(NULL, "NumNTorsPerTAP",
+                                       DEFAULT_NUM_NTORS_PER_TAP,
+                                       MIN_NUM_NTORS_PER_TAP,
+                                       MAX_NUM_NTORS_PER_TAP);
+  tor_assert(result > 0);
+  return result;
 }
 
 /** Choose which onion queue we'll pull from next. If one is empty choose
diff --git a/src/feature/relay/onion_queue.h b/src/feature/relay/onion_queue.h
index 0df921e05..cf478bc1a 100644
--- a/src/feature/relay/onion_queue.h
+++ b/src/feature/relay/onion_queue.h
@@ -20,4 +20,4 @@ int onion_num_pending(uint16_t handshake_type);
 void onion_pending_remove(or_circuit_t *circ);
 void clear_pending_onions(void);
 
-#endif
+#endif /* !defined(TOR_ONION_QUEUE_H) */
diff --git a/src/feature/relay/relay_periodic.c b/src/feature/relay/relay_periodic.c
new file mode 100644
index 000000000..b48b49589
--- /dev/null
+++ b/src/feature/relay/relay_periodic.c
@@ -0,0 +1,308 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file relay_periodic.c
+ * @brief Periodic functions for the relay subsytem
+ **/
+
+#include "orconfig.h"
+#include "core/or/or.h"
+
+#include "core/mainloop/periodic.h"
+#include "core/mainloop/cpuworker.h" // XXXX use a pubsub event.
+#include "core/mainloop/mainloop.h"
+#include "core/mainloop/netstatus.h"
+#include "core/or/circuituse.h" // XXXX move have_performed_bandwidth_test
+
+#include "feature/relay/dns.h"
+#include "feature/relay/relay_periodic.h"
+#include "feature/relay/router.h"
+#include "feature/relay/routerkeys.h"
+#include "feature/relay/routermode.h"
+#include "feature/relay/selftest.h"
+#include "feature/stats/predict_ports.h"
+
+#include "lib/crypt_ops/crypto_rand.h"
+
+#include "feature/nodelist/routerinfo_st.h"
+#include "feature/control/control_events.h"
+
+#define DECLARE_EVENT(name, roles, flags)         \
+  static periodic_event_item_t name ## _event =   \
+    PERIODIC_EVENT(name,                          \
+                   PERIODIC_EVENT_ROLE_##roles,   \
+                   flags)
+
+#define FL(name) (PERIODIC_EVENT_FLAG_##name)
+
+/**
+ * Periodic callback: If we're a server and initializing dns failed, retry.
+ */
+static int
+retry_dns_callback(time_t now, const or_options_t *options)
+{
+  (void)now;
+#define RETRY_DNS_INTERVAL (10*60)
+  if (server_mode(options) && has_dns_init_failed())
+    dns_init();
+  return RETRY_DNS_INTERVAL;
+}
+
+DECLARE_EVENT(retry_dns, ROUTER, 0);
+
+static int dns_honesty_first_time = 1;
+
+/**
+ * Periodic event: if we're an exit, see if our DNS server is telling us
+ * obvious lies.
+ */
+static int
+check_dns_honesty_callback(time_t now, const or_options_t *options)
+{
+  (void)now;
+  /* 9. and if we're an exit node, check whether our DNS is telling stories
+   * to us. */
+  if (net_is_disabled() ||
+      ! public_server_mode(options) ||
+      router_my_exit_policy_is_reject_star())
+    return PERIODIC_EVENT_NO_UPDATE;
+
+  if (dns_honesty_first_time) {
+    /* Don't launch right when we start */
+    dns_honesty_first_time = 0;
+    return crypto_rand_int_range(60, 180);
+  }
+
+  dns_launch_correctness_checks();
+  return 12*3600 + crypto_rand_int(12*3600);
+}
+
+DECLARE_EVENT(check_dns_honesty, RELAY, FL(NEED_NET));
+
+/* Periodic callback: rotate the onion keys after the period defined by the
+ * "onion-key-rotation-days" consensus parameter, shut down and restart all
+ * cpuworkers, and update our descriptor if necessary.
+ */
+static int
+rotate_onion_key_callback(time_t now, const or_options_t *options)
+{
+  if (server_mode(options)) {
+    int onion_key_lifetime = get_onion_key_lifetime();
+    time_t rotation_time = get_onion_key_set_at()+onion_key_lifetime;
+    if (rotation_time > now) {
+      return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
+    }
+
+    log_info(LD_GENERAL,"Rotating onion key.");
+    rotate_onion_key();
+    cpuworkers_rotate_keyinfo();
+    if (router_rebuild_descriptor(1)<0) {
+      log_info(LD_CONFIG, "Couldn't rebuild router descriptor");
+    }
+    if (advertised_server_mode() && !net_is_disabled())
+      router_upload_dir_desc_to_dirservers(0);
+    return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
+  }
+  return PERIODIC_EVENT_NO_UPDATE;
+}
+
+DECLARE_EVENT(rotate_onion_key, ROUTER, 0);
+
+/** Periodic callback: consider rebuilding or and re-uploading our descriptor
+ * (if we've passed our internal checks). */
+static int
+check_descriptor_callback(time_t now, const or_options_t *options)
+{
+/** How often do we check whether part of our router info has changed in a
+ * way that would require an upload? That includes checking whether our IP
+ * address has changed. */
+#define CHECK_DESCRIPTOR_INTERVAL (60)
+
+  (void)options;
+
+  /* 2b. Once per minute, regenerate and upload the descriptor if the old
+   * one is inaccurate. */
+  if (!net_is_disabled()) {
+    check_descriptor_bandwidth_changed(now);
+    check_descriptor_ipaddress_changed(now);
+    mark_my_descriptor_dirty_if_too_old(now);
+    consider_publishable_server(0);
+  }
+
+  return CHECK_DESCRIPTOR_INTERVAL;
+}
+
+DECLARE_EVENT(check_descriptor, ROUTER, FL(NEED_NET));
+
+static int dirport_reachability_count = 0;
+
+/**
+ * Periodic callback: check whether we're reachable (as a relay), and
+ * whether our bandwidth has changed enough that we need to
+ * publish a new descriptor.
+ */
+static int
+check_for_reachability_bw_callback(time_t now, const or_options_t *options)
+{
+  /* XXXX This whole thing was stuck in the middle of what is now
+   * XXXX check_descriptor_callback.  I'm not sure it's right. */
+
+  /* also, check religiously for reachability, if it's within the first
+   * 20 minutes of our uptime. */
+  if (server_mode(options) &&
+      (have_completed_a_circuit() || !any_predicted_circuits(now)) &&
+      !net_is_disabled()) {
+    if (get_uptime() < TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT) {
+      router_do_reachability_checks(1, dirport_reachability_count==0);
+      if (++dirport_reachability_count > 5)
+        dirport_reachability_count = 0;
+      return 1;
+    } else {
+      /* If we haven't checked for 12 hours and our bandwidth estimate is
+       * low, do another bandwidth test. This is especially important for
+       * bridges, since they might go long periods without much use. */
+      const routerinfo_t *me = router_get_my_routerinfo();
+      static int first_time = 1;
+      if (!first_time && me &&
+          me->bandwidthcapacity < me->bandwidthrate &&
+          me->bandwidthcapacity < 51200) {
+        reset_bandwidth_test();
+      }
+      first_time = 0;
+#define BANDWIDTH_RECHECK_INTERVAL (12*60*60)
+      return BANDWIDTH_RECHECK_INTERVAL;
+    }
+  }
+  return CHECK_DESCRIPTOR_INTERVAL;
+}
+
+DECLARE_EVENT(check_for_reachability_bw, ROUTER, FL(NEED_NET));
+
+/**
+ * Callback: Send warnings if Tor doesn't find its ports reachable.
+ */
+static int
+reachability_warnings_callback(time_t now, const or_options_t *options)
+{
+  (void) now;
+
+  if (get_uptime() < TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT) {
+    return (int)(TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT - get_uptime());
+  }
+
+  if (server_mode(options) &&
+      !net_is_disabled() &&
+      have_completed_a_circuit()) {
+    /* every 20 minutes, check and complain if necessary */
+    const routerinfo_t *me = router_get_my_routerinfo();
+    if (me && !check_whether_orport_reachable(options)) {
+      char *address = tor_dup_ip(me->addr);
+      log_warn(LD_CONFIG,"Your server (%s:%d) has not managed to confirm that "
+               "its ORPort is reachable. Relays do not publish descriptors "
+               "until their ORPort and DirPort are reachable. Please check "
+               "your firewalls, ports, address, /etc/hosts file, etc.",
+               address, me->or_port);
+      control_event_server_status(LOG_WARN,
+                                  "REACHABILITY_FAILED ORADDRESS=%s:%d",
+                                  address, me->or_port);
+      tor_free(address);
+    }
+
+    if (me && !check_whether_dirport_reachable(options)) {
+      char *address = tor_dup_ip(me->addr);
+      log_warn(LD_CONFIG,
+               "Your server (%s:%d) has not managed to confirm that its "
+               "DirPort is reachable. Relays do not publish descriptors "
+               "until their ORPort and DirPort are reachable. Please check "
+               "your firewalls, ports, address, /etc/hosts file, etc.",
+               address, me->dir_port);
+      control_event_server_status(LOG_WARN,
+                                  "REACHABILITY_FAILED DIRADDRESS=%s:%d",
+                                  address, me->dir_port);
+      tor_free(address);
+    }
+  }
+
+  return TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT;
+}
+
+DECLARE_EVENT(reachability_warnings, ROUTER, FL(NEED_NET));
+
+/* Periodic callback: Every 30 seconds, check whether it's time to make new
+ * Ed25519 subkeys.
+ */
+static int
+check_ed_keys_callback(time_t now, const or_options_t *options)
+{
+  if (server_mode(options)) {
+    if (should_make_new_ed_keys(options, now)) {
+      int new_signing_key = load_ed_keys(options, now);
+      if (new_signing_key < 0 ||
+          generate_ed_link_cert(options, now, new_signing_key > 0)) {
+        log_err(LD_OR, "Unable to update Ed25519 keys!  Exiting.");
+        tor_shutdown_event_loop_and_exit(1);
+      }
+    }
+    return 30;
+  }
+  return PERIODIC_EVENT_NO_UPDATE;
+}
+
+DECLARE_EVENT(check_ed_keys, ROUTER, 0);
+
+/* Period callback: Check if our old onion keys are still valid after the
+ * period of time defined by the consensus parameter
+ * "onion-key-grace-period-days", otherwise expire them by setting them to
+ * NULL.
+ */
+static int
+check_onion_keys_expiry_time_callback(time_t now, const or_options_t *options)
+{
+  if (server_mode(options)) {
+    int onion_key_grace_period = get_onion_key_grace_period();
+    time_t expiry_time = get_onion_key_set_at()+onion_key_grace_period;
+    if (expiry_time > now) {
+      return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
+    }
+
+    log_info(LD_GENERAL, "Expiring old onion keys.");
+    expire_old_onion_keys();
+    cpuworkers_rotate_keyinfo();
+    return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
+  }
+
+  return PERIODIC_EVENT_NO_UPDATE;
+}
+
+DECLARE_EVENT(check_onion_keys_expiry_time, ROUTER, 0);
+
+void
+relay_register_periodic_events(void)
+{
+  periodic_events_register(&retry_dns_event);
+  periodic_events_register(&check_dns_honesty_event);
+  periodic_events_register(&rotate_onion_key_event);
+  periodic_events_register(&check_descriptor_event);
+  periodic_events_register(&check_for_reachability_bw_event);
+  periodic_events_register(&reachability_warnings_event);
+  periodic_events_register(&check_ed_keys_event);
+  periodic_events_register(&check_onion_keys_expiry_time_event);
+
+  dns_honesty_first_time = 1;
+  dirport_reachability_count = 0;
+}
+
+/**
+ * Update our schedule so that we'll check whether we need to update our
+ * descriptor immediately, rather than after up to CHECK_DESCRIPTOR_INTERVAL
+ * seconds.
+ */
+void
+reschedule_descriptor_update_check(void)
+{
+  periodic_event_reschedule(&check_descriptor_event);
+}
diff --git a/src/feature/relay/relay_periodic.h b/src/feature/relay/relay_periodic.h
new file mode 100644
index 000000000..b6ea83c74
--- /dev/null
+++ b/src/feature/relay/relay_periodic.h
@@ -0,0 +1,18 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file relay_periodic.h
+ * @brief Header for feature/relay/relay_periodic.c
+ **/
+
+#ifndef TOR_FEATURE_RELAY_RELAY_PERIODIC_H
+#define TOR_FEATURE_RELAY_RELAY_PERIODIC_H
+
+void relay_register_periodic_events(void);
+void reschedule_descriptor_update_check(void);
+
+#endif /* !defined(TOR_FEATURE_RELAY_RELAY_PERIODIC_H) */
diff --git a/src/feature/relay/relay_sys.c b/src/feature/relay/relay_sys.c
new file mode 100644
index 000000000..106e88b2a
--- /dev/null
+++ b/src/feature/relay/relay_sys.c
@@ -0,0 +1,48 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file relay_sys.c
+ * @brief Subsystem definitions for the relay module.
+ **/
+
+#include "orconfig.h"
+#include "core/or/or.h"
+
+#include "feature/relay/dns.h"
+#include "feature/relay/ext_orport.h"
+#include "feature/relay/onion_queue.h"
+#include "feature/relay/relay_periodic.h"
+#include "feature/relay/relay_sys.h"
+#include "feature/relay/routerkeys.h"
+#include "feature/relay/router.h"
+
+#include "lib/subsys/subsys.h"
+
+static int
+subsys_relay_initialize(void)
+{
+  relay_register_periodic_events();
+  return 0;
+}
+
+static void
+subsys_relay_shutdown(void)
+{
+  dns_free_all();
+  ext_orport_free_all();
+  clear_pending_onions();
+  routerkeys_free_all();
+  router_free_all();
+}
+
+const struct subsys_fns_t sys_relay = {
+  .name = "relay",
+  .supported = true,
+  .level = 50,
+  .initialize = subsys_relay_initialize,
+  .shutdown = subsys_relay_shutdown,
+};
diff --git a/src/feature/relay/relay_sys.h b/src/feature/relay/relay_sys.h
new file mode 100644
index 000000000..32e21d90d
--- /dev/null
+++ b/src/feature/relay/relay_sys.h
@@ -0,0 +1,17 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file relay_sys.h
+ * @brief Header for feature/relay/relay_sys.c
+ **/
+
+#ifndef TOR_FEATURE_RELAY_RELAY_SYS_H
+#define TOR_FEATURE_RELAY_RELAY_SYS_H
+
+extern const struct subsys_fns_t sys_relay;
+
+#endif /* !defined(TOR_FEATURE_RELAY_RELAY_SYS_H) */
diff --git a/src/feature/relay/router.c b/src/feature/relay/router.c
index cdd032f78..25bb1835c 100644
--- a/src/feature/relay/router.c
+++ b/src/feature/relay/router.c
@@ -16,7 +16,7 @@
 #include "core/or/policies.h"
 #include "core/or/protover.h"
 #include "feature/client/transports.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirauth/process_descs.h"
 #include "feature/dircache/dirserv.h"
 #include "feature/dirclient/dirclient.h"
@@ -152,6 +152,8 @@ routerinfo_err_to_string(int err)
       return "Cannot generate descriptor";
     case TOR_ROUTERINFO_ERROR_DESC_REBUILDING:
       return "Descriptor still rebuilding - not ready yet";
+    case TOR_ROUTERINFO_ERROR_INTERNAL_BUG:
+      return "Internal bug, see logs for details";
   }
 
   log_warn(LD_BUG, "unknown routerinfo error %d - shouldn't happen", err);
@@ -194,8 +196,8 @@ set_onion_key(crypto_pk_t *k)
 
 /** Return the current onion key.  Requires that the onion key has been
  * loaded or generated. */
-crypto_pk_t *
-get_onion_key(void)
+MOCK_IMPL(crypto_pk_t *,
+get_onion_key,(void))
 {
   tor_assert(onionkey);
   return onionkey;
@@ -242,7 +244,7 @@ expire_old_onion_keys(void)
     lastonionkey = NULL;
   }
 
-  /* We zero out the keypair. See the tor_mem_is_zero() check made in
+  /* We zero out the keypair. See the fast_mem_is_zero() check made in
    * construct_ntor_key_map() below. */
   memset(&last_curve25519_onion_key, 0, sizeof(last_curve25519_onion_key));
 
@@ -269,11 +271,12 @@ expire_old_onion_keys(void)
 
 /** Return the current secret onion key for the ntor handshake. Must only
  * be called from the main thread. */
-static const curve25519_keypair_t *
-get_current_curve25519_keypair(void)
+MOCK_IMPL(STATIC const struct curve25519_keypair_t *,
+get_current_curve25519_keypair,(void))
 {
   return &curve25519_onion_key;
 }
+
 /** Return a map from KEYID (the key itself) to keypairs for use in the ntor
  * handshake. Must only be called from the main thread. */
 di_digest256_map_t *
@@ -281,7 +284,7 @@ construct_ntor_key_map(void)
 {
   di_digest256_map_t *m = NULL;
 
-  if (!tor_mem_is_zero((const char*)
+  if (!fast_mem_is_zero((const char*)
                        curve25519_onion_key.pubkey.public_key,
                        CURVE25519_PUBKEY_LEN)) {
     dimap_add_entry(&m,
@@ -289,7 +292,7 @@ construct_ntor_key_map(void)
                     tor_memdup(&curve25519_onion_key,
                                sizeof(curve25519_keypair_t)));
   }
-  if (!tor_mem_is_zero((const char*)
+  if (!fast_mem_is_zero((const char*)
                           last_curve25519_onion_key.pubkey.public_key,
                        CURVE25519_PUBKEY_LEN)) {
     dimap_add_entry(&m,
@@ -350,7 +353,7 @@ set_server_identity_key_digest_testing(const uint8_t *digest)
 {
   memcpy(server_identitykey_digest, digest, DIGEST_LEN);
 }
-#endif
+#endif /* defined(TOR_UNIT_TESTS) */
 
 /** Make sure that we have set up our identity keys to match or not match as
  * appropriate, and die with an assertion if we have not. */
@@ -374,8 +377,8 @@ assert_identity_keys_ok(void)
 /** Returns the current server identity key; requires that the key has
  * been set, and that we are running as a Tor server.
  */
-crypto_pk_t *
-get_server_identity_key(void)
+MOCK_IMPL(crypto_pk_t *,
+get_server_identity_key,(void))
 {
   tor_assert(server_identitykey);
   tor_assert(server_mode(get_options()));
@@ -1046,7 +1049,7 @@ init_keys(void)
       return -1;
 
     keydir = get_keydir_fname("secret_onion_key_ntor.old");
-    if (tor_mem_is_zero((const char *)
+    if (fast_mem_is_zero((const char *)
                            last_curve25519_onion_key.pubkey.public_key,
                         CURVE25519_PUBKEY_LEN) &&
         file_status(keydir) == FN_FILE) {
@@ -1941,26 +1944,33 @@ get_my_declared_family(const or_options_t *options)
   return result;
 }
 
-/** Build a fresh routerinfo, signed server descriptor, and extra-info document
- * for this OR. Set r to the generated routerinfo, e to the generated
- * extra-info document. Return 0 on success, -1 on temporary error. Failure to
- * generate an extra-info document is not an error and is indicated by setting
- * e to NULL. Caller is responsible for freeing generated documents if 0 is
- * returned.
+/** Allocate a fresh, unsigned routerinfo for this OR, without any of the
+ * fields that depend on the corresponding extrainfo.
+ *
+ * On success, set ri_out to the new routerinfo, and return 0.
+ * Caller is responsible for freeing the generated routerinfo.
+ *
+ * Returns a negative value and sets ri_out to NULL on temporary error.
  */
-int
-router_build_fresh_descriptor(routerinfo_t **r, extrainfo_t **e)
+MOCK_IMPL(STATIC int,
+router_build_fresh_unsigned_routerinfo,(routerinfo_t **ri_out))
 {
-  routerinfo_t *ri;
-  extrainfo_t *ei;
+  routerinfo_t *ri = NULL;
   uint32_t addr;
   char platform[256];
   int hibernating = we_are_hibernating();
   const or_options_t *options = get_options();
+  int result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
+
+  if (BUG(!ri_out)) {
+    result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
+    goto err;
+  }
 
   if (router_pick_published_address(options, &addr, 0) < 0) {
     log_warn(LD_CONFIG, "Don't know my address while generating descriptor");
-    return TOR_ROUTERINFO_ERROR_NO_EXT_ADDR;
+    result = TOR_ROUTERINFO_ERROR_NO_EXT_ADDR;
+    goto err;
   }
 
   /* Log a message if the address in the descriptor doesn't match the ORPort
@@ -2017,8 +2027,8 @@ router_build_fresh_descriptor(routerinfo_t **r, extrainfo_t **e)
   ri->identity_pkey = crypto_pk_dup_key(get_server_identity_key());
   if (BUG(crypto_pk_get_digest(ri->identity_pkey,
                            ri->cache_info.identity_digest) < 0)) {
-    routerinfo_free(ri);
-    return TOR_ROUTERINFO_ERROR_DIGEST_FAILED;
+    result = TOR_ROUTERINFO_ERROR_DIGEST_FAILED;
+    goto err;
   }
   ri->cache_info.signing_key_cert =
     tor_cert_dup(get_master_signing_key_cert());
@@ -2057,85 +2067,258 @@ router_build_fresh_descriptor(routerinfo_t **r, extrainfo_t **e)
 
   ri->declared_family = get_my_declared_family(options);
 
+  if (options->BridgeRelay) {
+    ri->purpose = ROUTER_PURPOSE_BRIDGE;
+    /* Bridges shouldn't be able to send their descriptors unencrypted,
+     anyway, since they don't have a DirPort, and always connect to the
+     bridge authority anonymously.  But just in case they somehow think of
+     sending them on an unencrypted connection, don't allow them to try. */
+    ri->cache_info.send_unencrypted = 0;
+  } else {
+    ri->purpose = ROUTER_PURPOSE_GENERAL;
+    ri->cache_info.send_unencrypted = 1;
+  }
+
+  goto done;
+
+ err:
+  routerinfo_free(ri);
+  *ri_out = NULL;
+  return result;
+
+ done:
+  *ri_out = ri;
+  return 0;
+}
+
+/** Allocate and return a fresh, unsigned extrainfo for this OR, based on the
+ * routerinfo ri.
+ *
+ * Uses options->Nickname to set the nickname, and options->BridgeRelay to set
+ * ei->cache_info.send_unencrypted.
+ *
+ * If ri is NULL, logs a BUG() warning and returns NULL.
+ * Caller is responsible for freeing the generated extrainfo.
+ */
+static extrainfo_t *
+router_build_fresh_unsigned_extrainfo(const routerinfo_t *ri)
+{
+  extrainfo_t *ei = NULL;
+  const or_options_t *options = get_options();
+
+  if (BUG(!ri))
+    return NULL;
+
   /* Now generate the extrainfo. */
   ei = tor_malloc_zero(sizeof(extrainfo_t));
   ei->cache_info.is_extrainfo = 1;
-  strlcpy(ei->nickname, get_options()->Nickname, sizeof(ei->nickname));
+  strlcpy(ei->nickname, options->Nickname, sizeof(ei->nickname));
   ei->cache_info.published_on = ri->cache_info.published_on;
   ei->cache_info.signing_key_cert =
     tor_cert_dup(get_master_signing_key_cert());
 
   memcpy(ei->cache_info.identity_digest, ri->cache_info.identity_digest,
          DIGEST_LEN);
+
+  if (options->BridgeRelay) {
+    /* See note in router_build_fresh_routerinfo(). */
+    ei->cache_info.send_unencrypted = 0;
+  } else {
+    ei->cache_info.send_unencrypted = 1;
+  }
+
+  return ei;
+}
+
+/** Dump the extrainfo descriptor body for ei, sign it, and add the body and
+ * signature to ei->cache_info. Note that the extrainfo body is determined by
+ * ei, and some additional config and statistics state: see
+ * extrainfo_dump_to_string() for details.
+ *
+ * Return 0 on success, -1 on temporary error.
+ * If ei is NULL, logs a BUG() warning and returns -1.
+ * On error, ei->cache_info is not modified.
+ */
+static int
+router_dump_and_sign_extrainfo_descriptor_body(extrainfo_t *ei)
+{
+  if (BUG(!ei))
+    return -1;
+
   if (extrainfo_dump_to_string(&ei->cache_info.signed_descriptor_body,
                                ei, get_server_identity_key(),
                                get_master_signing_keypair()) < 0) {
     log_warn(LD_BUG, "Couldn't generate extra-info descriptor.");
-    extrainfo_free(ei);
-    ei = NULL;
-  } else {
-    ei->cache_info.signed_descriptor_len =
-      strlen(ei->cache_info.signed_descriptor_body);
-    router_get_extrainfo_hash(ei->cache_info.signed_descriptor_body,
-                              ei->cache_info.signed_descriptor_len,
-                              ei->cache_info.signed_descriptor_digest);
-    crypto_digest256((char*) ei->digest256,
-                     ei->cache_info.signed_descriptor_body,
-                     ei->cache_info.signed_descriptor_len,
-                     DIGEST_SHA256);
+    return -1;
   }
 
-  /* Now finish the router descriptor. */
-  if (ei) {
-    memcpy(ri->cache_info.extra_info_digest,
-           ei->cache_info.signed_descriptor_digest,
-           DIGEST_LEN);
-    memcpy(ri->cache_info.extra_info_digest256,
-           ei->digest256,
-           DIGEST256_LEN);
-  } else {
-    /* ri was allocated with tor_malloc_zero, so there is no need to
-     * zero ri->cache_info.extra_info_digest here. */
+  ei->cache_info.signed_descriptor_len =
+    strlen(ei->cache_info.signed_descriptor_body);
+
+  router_get_extrainfo_hash(ei->cache_info.signed_descriptor_body,
+                            ei->cache_info.signed_descriptor_len,
+                            ei->cache_info.signed_descriptor_digest);
+  crypto_digest256((char*) ei->digest256,
+                   ei->cache_info.signed_descriptor_body,
+                   ei->cache_info.signed_descriptor_len,
+                   DIGEST_SHA256);
+
+  return 0;
+}
+
+/** Allocate and return a fresh, signed extrainfo for this OR, based on the
+ * routerinfo ri.
+ *
+ * If ri is NULL, logs a BUG() warning and returns NULL.
+ * Caller is responsible for freeing the generated extrainfo.
+ */
+STATIC extrainfo_t *
+router_build_fresh_signed_extrainfo(const routerinfo_t *ri)
+{
+  int result = -1;
+  extrainfo_t *ei = NULL;
+
+  if (BUG(!ri))
+    return NULL;
+
+  ei = router_build_fresh_unsigned_extrainfo(ri);
+  /* router_build_fresh_unsigned_extrainfo() should not fail. */
+  if (BUG(!ei))
+    goto err;
+
+  result = router_dump_and_sign_extrainfo_descriptor_body(ei);
+  if (result < 0)
+    goto err;
+
+  goto done;
+
+ err:
+  extrainfo_free(ei);
+  return NULL;
+
+ done:
+  return ei;
+}
+
+/** Set the fields in ri that depend on ei.
+ *
+ * If ei is NULL, logs a BUG() warning and zeroes the relevant fields.
+ */
+STATIC void
+router_update_routerinfo_from_extrainfo(routerinfo_t *ri,
+                                        const extrainfo_t *ei)
+{
+  if (BUG(!ei)) {
+    /* Just to be safe, zero ri->cache_info.extra_info_digest here. */
+    memset(ri->cache_info.extra_info_digest, 0, DIGEST_LEN);
+    memset(ri->cache_info.extra_info_digest256, 0, DIGEST256_LEN);
+    return;
   }
+
+  /* Now finish the router descriptor. */
+  memcpy(ri->cache_info.extra_info_digest,
+         ei->cache_info.signed_descriptor_digest,
+         DIGEST_LEN);
+  memcpy(ri->cache_info.extra_info_digest256,
+         ei->digest256,
+         DIGEST256_LEN);
+}
+
+/** Dump the descriptor body for ri, sign it, and add the body and signature to
+ * ri->cache_info. Note that the descriptor body is determined by ri, and some
+ * additional config and state: see router_dump_router_to_string() for details.
+ *
+ * Return 0 on success, and a negative value on temporary error.
+ * If ri is NULL, logs a BUG() warning and returns a negative value.
+ * On error, ri->cache_info is not modified.
+ */
+STATIC int
+router_dump_and_sign_routerinfo_descriptor_body(routerinfo_t *ri)
+{
+  if (BUG(!ri))
+    return TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
+
   if (! (ri->cache_info.signed_descriptor_body =
           router_dump_router_to_string(ri, get_server_identity_key(),
                                        get_onion_key(),
                                        get_current_curve25519_keypair(),
                                        get_master_signing_keypair())) ) {
     log_warn(LD_BUG, "Couldn't generate router descriptor.");
-    routerinfo_free(ri);
-    extrainfo_free(ei);
     return TOR_ROUTERINFO_ERROR_CANNOT_GENERATE;
   }
+
   ri->cache_info.signed_descriptor_len =
     strlen(ri->cache_info.signed_descriptor_body);
 
-  ri->purpose =
-    options->BridgeRelay ? ROUTER_PURPOSE_BRIDGE : ROUTER_PURPOSE_GENERAL;
-  if (options->BridgeRelay) {
-    /* Bridges shouldn't be able to send their descriptors unencrypted,
-       anyway, since they don't have a DirPort, and always connect to the
-       bridge authority anonymously.  But just in case they somehow think of
-       sending them on an unencrypted connection, don't allow them to try. */
-    ri->cache_info.send_unencrypted = 0;
-    if (ei)
-      ei->cache_info.send_unencrypted = 0;
-  } else {
-    ri->cache_info.send_unencrypted = 1;
-    if (ei)
-      ei->cache_info.send_unencrypted = 1;
-  }
-
   router_get_router_hash(ri->cache_info.signed_descriptor_body,
                          strlen(ri->cache_info.signed_descriptor_body),
                          ri->cache_info.signed_descriptor_digest);
 
+  return 0;
+}
+
+/** Build a fresh routerinfo, signed server descriptor, and signed extrainfo
+ * document for this OR.
+ *
+ * Set r to the generated routerinfo, e to the generated extrainfo document.
+ * Failure to generate an extra-info document is not an error and is indicated
+ * by setting e to NULL.
+ * Return 0 on success, and a negative value on temporary error.
+ * Caller is responsible for freeing generated documents on success.
+ */
+int
+router_build_fresh_descriptor(routerinfo_t **r, extrainfo_t **e)
+{
+  int result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
+  routerinfo_t *ri = NULL;
+  extrainfo_t *ei = NULL;
+
+  if (BUG(!r))
+    goto err;
+
+  if (BUG(!e))
+    goto err;
+
+  result = router_build_fresh_unsigned_routerinfo(&ri);
+  if (result < 0) {
+    goto err;
+  }
+  /* If ri is NULL, then result should be negative. So this check should be
+   * unreachable. */
+  if (BUG(!ri)) {
+    result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
+    goto err;
+  }
+
+  ei = router_build_fresh_signed_extrainfo(ri);
+
+  /* Failing to create an ei is not an error. */
+  if (ei) {
+    router_update_routerinfo_from_extrainfo(ri, ei);
+  }
+
+  result = router_dump_and_sign_routerinfo_descriptor_body(ri);
+  if (result < 0)
+    goto err;
+
   if (ei) {
-    tor_assert(!
-          routerinfo_incompatible_with_extrainfo(ri->identity_pkey, ei,
-                                                 &ri->cache_info, NULL));
+     if (BUG(routerinfo_incompatible_with_extrainfo(ri->identity_pkey, ei,
+                                                    &ri->cache_info, NULL))) {
+       result = TOR_ROUTERINFO_ERROR_INTERNAL_BUG;
+       goto err;
+     }
   }
 
+  goto done;
+
+ err:
+  routerinfo_free(ri);
+  extrainfo_free(ei);
+  *r = NULL;
+  *e = NULL;
+  return result;
+
+ done:
   *r = ri;
   *e = ei;
   return 0;
@@ -2478,6 +2661,10 @@ get_platform_str(char *platform, size_t len)
 /** OR only: Given a routerinfo for this router, and an identity key to sign
  * with, encode the routerinfo as a signed server descriptor and return a new
  * string encoding the result, or NULL on failure.
+ *
+ * In addition to the fields in router, this function calls
+ * onion_key_lifetime(), get_options(), and we_are_hibernating(), and uses the
+ * results to populate some fields in the descriptor.
  */
 char *
 router_dump_router_to_string(routerinfo_t *router,
@@ -2541,11 +2728,8 @@ router_dump_router_to_string(routerinfo_t *router,
       log_err(LD_BUG,"Couldn't base64-encode signing key certificate!");
       goto err;
     }
-    if (ed25519_public_to_base64(ed_fp_base64,
-                       &router->cache_info.signing_key_cert->signing_key)<0) {
-      log_err(LD_BUG,"Couldn't base64-encode identity key\n");
-      goto err;
-    }
+    ed25519_public_to_base64(ed_fp_base64,
+                            &router->cache_info.signing_key_cert->signing_key);
     tor_asprintf(&ed_cert_line, "identity-ed25519\n"
                  "-----BEGIN ED25519 CERT-----\n"
                  "%s"
@@ -2790,8 +2974,7 @@ router_dump_router_to_string(routerinfo_t *router,
     if (ed25519_sign(&sig, (const uint8_t*)digest, DIGEST256_LEN,
                      signing_keypair) < 0)
       goto err;
-    if (ed25519_signature_to_base64(buf, &sig) < 0)
-      goto err;
+    ed25519_signature_to_base64(buf, &sig);
 
     smartlist_add_asprintf(chunks, "%s\n", buf);
   }
@@ -2930,9 +3113,14 @@ load_stats_file(const char *filename, const char *end_line, time_t now,
   return r;
 }
 
-/** Write the contents of <b>extrainfo</b> and aggregated statistics to
- * *<b>s_out</b>, signing them with <b>ident_key</b>. Return 0 on
- * success, negative on failure. */
+/** Write the contents of <b>extrainfo</b>, to * *<b>s_out</b>, signing them
+ * with <b>ident_key</b>.
+ *
+ * If ExtraInfoStatistics is 1, also write aggregated statistics and related
+ * configuration data before signing. Most statistics also have an option that
+ * enables or disables that particular statistic.
+ *
+ * Return 0 on success, negative on failure. */
 int
 extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
                          crypto_pk_t *ident_key,
@@ -2942,7 +3130,6 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
   char identity[HEX_DIGEST_LEN+1];
   char published[ISO_TIME_LEN+1];
   char digest[DIGEST_LEN];
-  char *bandwidth_usage;
   int result;
   static int write_stats_to_extrainfo = 1;
   char sig[DIROBJ_MAX_SIG_LEN+1];
@@ -2957,7 +3144,6 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
   base16_encode(identity, sizeof(identity),
                 extrainfo->cache_info.identity_digest, DIGEST_LEN);
   format_iso_time(published, extrainfo->cache_info.published_on);
-  bandwidth_usage = rep_hist_get_bandwidth_lines();
   if (emit_ed_sigs) {
     if (!extrainfo->cache_info.signing_key_cert->signing_key_included ||
         !ed25519_pubkey_eq(&extrainfo->cache_info.signing_key_cert->signed_key,
@@ -2983,21 +3169,35 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
     ed_cert_line = tor_strdup("");
   }
 
-  tor_asprintf(&pre, "extra-info %s %s\n%spublished %s\n%s",
+  tor_asprintf(&pre, "extra-info %s %s\n%spublished %s\n",
                extrainfo->nickname, identity,
                ed_cert_line,
-               published, bandwidth_usage);
+               published);
   smartlist_add(chunks, pre);
 
-  if (geoip_is_loaded(AF_INET))
-    smartlist_add_asprintf(chunks, "geoip-db-digest %s\n",
-                           geoip_db_digest(AF_INET));
-  if (geoip_is_loaded(AF_INET6))
-    smartlist_add_asprintf(chunks, "geoip6-db-digest %s\n",
-                           geoip_db_digest(AF_INET6));
+  /* Add information about the pluggable transports we support, even if we
+   * are not publishing statistics. This information is needed by BridgeDB
+   * to distribute bridges. */
+  if (options->ServerTransportPlugin) {
+    char *pluggable_transports = pt_get_extra_info_descriptor_string();
+    if (pluggable_transports)
+      smartlist_add(chunks, pluggable_transports);
+  }
 
   if (options->ExtraInfoStatistics && write_stats_to_extrainfo) {
     log_info(LD_GENERAL, "Adding stats to extra-info descriptor.");
+    /* Bandwidth usage stats don't have their own option */
+    {
+      contents = rep_hist_get_bandwidth_lines();
+      smartlist_add(chunks, contents);
+    }
+    /* geoip hashes aren't useful unless we are publishing other stats */
+    if (geoip_is_loaded(AF_INET))
+      smartlist_add_asprintf(chunks, "geoip-db-digest %s\n",
+                             geoip_db_digest(AF_INET));
+    if (geoip_is_loaded(AF_INET6))
+      smartlist_add_asprintf(chunks, "geoip6-db-digest %s\n",
+                             geoip_db_digest(AF_INET6));
     if (options->DirReqStatistics &&
         load_stats_file("stats"PATH_SEPARATOR"dirreq-stats",
                         "dirreq-stats-end", now, &contents) > 0) {
@@ -3033,19 +3233,12 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
       if (contents)
         smartlist_add(chunks, contents);
     }
-  }
-
-  /* Add information about the pluggable transports we support. */
-  if (options->ServerTransportPlugin) {
-    char *pluggable_transports = pt_get_extra_info_descriptor_string();
-    if (pluggable_transports)
-      smartlist_add(chunks, pluggable_transports);
-  }
-
-  if (should_record_bridge_info(options) && write_stats_to_extrainfo) {
-    const char *bridge_stats = geoip_get_bridge_stats_extrainfo(now);
-    if (bridge_stats) {
-      smartlist_add_strdup(chunks, bridge_stats);
+    /* bridge statistics */
+    if (should_record_bridge_info(options)) {
+      const char *bridge_stats = geoip_get_bridge_stats_extrainfo(now);
+      if (bridge_stats) {
+        smartlist_add_strdup(chunks, bridge_stats);
+      }
     }
   }
 
@@ -3060,8 +3253,7 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
     if (ed25519_sign(&ed_sig, (const uint8_t*)sha256_digest, DIGEST256_LEN,
                      signing_keypair) < 0)
       goto err;
-    if (ed25519_signature_to_base64(buf, &ed_sig) < 0)
-      goto err;
+    ed25519_signature_to_base64(buf, &ed_sig);
 
     smartlist_add_asprintf(chunks, "%s\n", buf);
   }
@@ -3139,7 +3331,6 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
   tor_free(s_dup);
   tor_free(ed_cert_line);
   extrainfo_free(ei_tmp);
-  tor_free(bandwidth_usage);
 
   return result;
 }
diff --git a/src/feature/relay/router.h b/src/feature/relay/router.h
index 60bc857ce..55b9ef9e6 100644
--- a/src/feature/relay/router.h
+++ b/src/feature/relay/router.h
@@ -23,11 +23,12 @@ struct ed25519_keypair_t;
 #define TOR_ROUTERINFO_ERROR_DIGEST_FAILED   (-4)
 #define TOR_ROUTERINFO_ERROR_CANNOT_GENERATE (-5)
 #define TOR_ROUTERINFO_ERROR_DESC_REBUILDING (-6)
+#define TOR_ROUTERINFO_ERROR_INTERNAL_BUG    (-7)
 
-crypto_pk_t *get_onion_key(void);
+MOCK_DECL(crypto_pk_t *,get_onion_key,(void));
 time_t get_onion_key_set_at(void);
 void set_server_identity_key(crypto_pk_t *k);
-crypto_pk_t *get_server_identity_key(void);
+MOCK_DECL(crypto_pk_t *,get_server_identity_key,(void));
 int server_identity_key_is_set(void);
 void set_client_identity_key(crypto_pk_t *k);
 crypto_pk_t *get_tlsclient_identity_key(void);
@@ -114,7 +115,7 @@ void router_reset_reachability(void);
 void router_free_all(void);
 
 #ifdef ROUTER_PRIVATE
-/* Used only by router.c and test.c */
+/* Used only by router.c and the unit tests */
 STATIC void get_platform_str(char *platform, size_t len);
 STATIC int router_write_fingerprint(int hashed);
 STATIC smartlist_t *get_my_declared_family(const or_options_t *options);
@@ -123,8 +124,18 @@ STATIC smartlist_t *get_my_declared_family(const or_options_t *options);
 extern time_t desc_clean_since;
 extern const char *desc_dirty_reason;
 void set_server_identity_key_digest_testing(const uint8_t *digest);
-#endif
-
-#endif
+MOCK_DECL(STATIC const struct curve25519_keypair_t *,
+                                       get_current_curve25519_keypair,(void));
+
+MOCK_DECL(STATIC int,
+              router_build_fresh_unsigned_routerinfo,(routerinfo_t **ri_out));
+STATIC extrainfo_t *router_build_fresh_signed_extrainfo(
+                                                      const routerinfo_t *ri);
+STATIC void router_update_routerinfo_from_extrainfo(routerinfo_t *ri,
+                                                    const extrainfo_t *ei);
+STATIC int router_dump_and_sign_routerinfo_descriptor_body(routerinfo_t *ri);
+#endif /* defined(TOR_UNIT_TESTS) */
+
+#endif /* defined(ROUTER_PRIVATE) */
 
 #endif /* !defined(TOR_ROUTER_H) */
diff --git a/src/feature/relay/routerkeys.c b/src/feature/relay/routerkeys.c
index 876f908d4..a9190b2e1 100644
--- a/src/feature/relay/routerkeys.c
+++ b/src/feature/relay/routerkeys.c
@@ -188,7 +188,7 @@ load_ed_keys(const or_options_t *options, time_t now)
 
     /* Check/Create the key directory */
     if (create_keys_directory(options) < 0)
-      return -1;
+      goto err;
 
     char *fname;
     if (options->master_key_fname) {
@@ -226,7 +226,7 @@ load_ed_keys(const or_options_t *options, time_t now)
         tor_free(fname);
       }
     }
-    if (tor_mem_is_zero((char*)id->seckey.seckey, sizeof(id->seckey)))
+    if (safe_mem_is_zero((char*)id->seckey.seckey, sizeof(id->seckey)))
       sign_signing_key_with_id = NULL;
     else
       sign_signing_key_with_id = id;
@@ -631,14 +631,14 @@ get_master_identity_keypair(void)
 }
 #endif /* defined(TOR_UNIT_TESTS) */
 
-const ed25519_keypair_t *
-get_master_signing_keypair(void)
+MOCK_IMPL(const ed25519_keypair_t *,
+get_master_signing_keypair,(void))
 {
   return master_signing_key;
 }
 
-const struct tor_cert_st *
-get_master_signing_key_cert(void)
+MOCK_IMPL(const struct tor_cert_st *,
+get_master_signing_key_cert,(void))
 {
   return signing_key_cert;
 }
@@ -706,6 +706,8 @@ make_tap_onion_key_crosscert(const crypto_pk_t *onion_key,
 
   *len_out = 0;
   if (crypto_pk_get_digest(rsa_id_key, (char*)signed_data) < 0) {
+    log_info(LD_OR, "crypto_pk_get_digest failed in "
+                    "make_tap_onion_key_crosscert!");
     return NULL;
   }
   memcpy(signed_data + DIGEST_LEN, master_id_key->pubkey, ED25519_PUBKEY_LEN);
@@ -713,8 +715,12 @@ make_tap_onion_key_crosscert(const crypto_pk_t *onion_key,
   int r = crypto_pk_private_sign(onion_key,
                                (char*)signature, sizeof(signature),
                                (const char*)signed_data, sizeof(signed_data));
-  if (r < 0)
+  if (r < 0) {
+    /* It's probably missing the private key */
+    log_info(LD_OR, "crypto_pk_private_sign failed in "
+                    "make_tap_onion_key_crosscert!");
     return NULL;
+  }
 
   *len_out = r;
 
diff --git a/src/feature/relay/routerkeys.h b/src/feature/relay/routerkeys.h
index 0badd3419..cde07b52c 100644
--- a/src/feature/relay/routerkeys.h
+++ b/src/feature/relay/routerkeys.h
@@ -7,8 +7,8 @@
 #include "lib/crypt_ops/crypto_ed25519.h"
 
 const ed25519_public_key_t *get_master_identity_key(void);
-const ed25519_keypair_t *get_master_signing_keypair(void);
-const struct tor_cert_st *get_master_signing_key_cert(void);
+MOCK_DECL(const ed25519_keypair_t *, get_master_signing_keypair,(void));
+MOCK_DECL(const struct tor_cert_st *, get_master_signing_key_cert,(void));
 
 const ed25519_keypair_t *get_current_auth_keypair(void);
 const struct tor_cert_st *get_current_link_cert_cert(void);
diff --git a/src/feature/relay/selftest.c b/src/feature/relay/selftest.c
index 064eea6c4..f8b54ff45 100644
--- a/src/feature/relay/selftest.c
+++ b/src/feature/relay/selftest.c
@@ -26,7 +26,7 @@
 #include "core/or/crypt_path_st.h"
 #include "core/or/origin_circuit_st.h"
 #include "core/or/relay.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirclient/dirclient.h"
 #include "feature/dircommon/directory.h"
 #include "feature/nodelist/authority_cert_st.h"
@@ -35,6 +35,7 @@
 #include "feature/nodelist/routerlist.h" // but...
 #include "feature/nodelist/routerset.h"
 #include "feature/nodelist/torcert.h"
+#include "feature/relay/relay_periodic.h"
 #include "feature/relay/router.h"
 #include "feature/relay/selftest.h"
 
diff --git a/src/feature/relay/selftest.h b/src/feature/relay/selftest.h
index a80ec8936..aea77ec79 100644
--- a/src/feature/relay/selftest.h
+++ b/src/feature/relay/selftest.h
@@ -21,4 +21,4 @@ void router_orport_found_reachable(void);
 void router_dirport_found_reachable(void);
 void router_perform_bandwidth_test(int num_circs, time_t now);
 
-#endif
+#endif /* !defined(TOR_SELFTEST_H) */
diff --git a/src/feature/rend/rend_authorized_client_st.h b/src/feature/rend/rend_authorized_client_st.h
index 7bd4f2fe8..51a1798fc 100644
--- a/src/feature/rend/rend_authorized_client_st.h
+++ b/src/feature/rend/rend_authorized_client_st.h
@@ -14,5 +14,5 @@ struct rend_authorized_client_t {
   crypto_pk_t *client_key;
 };
 
-#endif
+#endif /* !defined(REND_AUTHORIZED_CLIENT_ST_H) */
 
diff --git a/src/feature/rend/rend_encoded_v2_service_descriptor_st.h b/src/feature/rend/rend_encoded_v2_service_descriptor_st.h
index 05ff145d5..bd8a60f0d 100644
--- a/src/feature/rend/rend_encoded_v2_service_descriptor_st.h
+++ b/src/feature/rend/rend_encoded_v2_service_descriptor_st.h
@@ -13,5 +13,5 @@ struct rend_encoded_v2_service_descriptor_t {
   char *desc_str; /**< Descriptor string. */
 };
 
-#endif
+#endif /* !defined(REND_ENCODED_V2_SERVICE_DESCRIPTOR_ST_H) */
 
diff --git a/src/feature/rend/rend_intro_point_st.h b/src/feature/rend/rend_intro_point_st.h
index de6987e56..4882b6275 100644
--- a/src/feature/rend/rend_intro_point_st.h
+++ b/src/feature/rend/rend_intro_point_st.h
@@ -73,4 +73,4 @@ struct rend_intro_point_t {
   unsigned int circuit_established:1;
 };
 
-#endif
+#endif /* !defined(REND_INTRO_POINT_ST_H) */
diff --git a/src/feature/rend/rend_service_descriptor_st.h b/src/feature/rend/rend_service_descriptor_st.h
index aeb317806..ff7627ce9 100644
--- a/src/feature/rend/rend_service_descriptor_st.h
+++ b/src/feature/rend/rend_service_descriptor_st.h
@@ -30,5 +30,5 @@ struct rend_service_descriptor_t {
   smartlist_t *successful_uploads;
 };
 
-#endif
+#endif /* !defined(REND_SERVICE_DESCRIPTOR_ST_H) */
 
diff --git a/src/feature/rend/rendcache.c b/src/feature/rend/rendcache.c
index fadfb4388..c3f86d8c8 100644
--- a/src/feature/rend/rendcache.c
+++ b/src/feature/rend/rendcache.c
@@ -19,6 +19,8 @@
 #include "feature/rend/rend_intro_point_st.h"
 #include "feature/rend/rend_service_descriptor_st.h"
 
+#include "lib/ctime/di_ops.h"
+
 /** Map from service id (as generated by rend_get_service_id) to
  * rend_cache_entry_t. */
 STATIC strmap_t *rend_cache = NULL;
@@ -593,10 +595,10 @@ rend_cache_lookup_v2_desc_as_dir(const char *desc_id, const char **desc)
   char desc_id_digest[DIGEST_LEN];
   tor_assert(rend_cache_v2_dir);
   if (base32_decode(desc_id_digest, DIGEST_LEN,
-                    desc_id, REND_DESC_ID_V2_LEN_BASE32) < 0) {
+                    desc_id, REND_DESC_ID_V2_LEN_BASE32) != DIGEST_LEN) {
     log_fn(LOG_PROTOCOL_WARN, LD_REND,
            "Rejecting v2 rendezvous descriptor request -- descriptor ID "
-           "contains illegal characters: %s",
+           "has wrong length or illegal characters: %s",
            safe_str(desc_id));
     return -1;
   }
@@ -854,7 +856,8 @@ rend_cache_store_v2_desc_as_client(const char *desc,
     *entry = NULL;
   }
   if (base32_decode(want_desc_id, sizeof(want_desc_id),
-                    desc_id_base32, strlen(desc_id_base32)) != 0) {
+                    desc_id_base32, strlen(desc_id_base32)) !=
+      sizeof(want_desc_id)) {
     log_warn(LD_BUG, "Couldn't decode base32 %s for descriptor id.",
              escaped_safe_str_client(desc_id_base32));
     goto err;
@@ -888,8 +891,8 @@ rend_cache_store_v2_desc_as_client(const char *desc,
   if (intro_content && intro_size > 0) {
     int n_intro_points;
     if (rend_data->auth_type != REND_NO_AUTH &&
-        !tor_mem_is_zero(rend_data->descriptor_cookie,
-                         sizeof(rend_data->descriptor_cookie))) {
+        !safe_mem_is_zero(rend_data->descriptor_cookie,
+                          sizeof(rend_data->descriptor_cookie))) {
       char *ipos_decrypted = NULL;
       size_t ipos_decrypted_size;
       if (rend_decrypt_introduction_points(&ipos_decrypted,
@@ -1005,4 +1008,3 @@ rend_cache_store_v2_desc_as_client(const char *desc,
   tor_free(intro_content);
   return retval;
 }
-
diff --git a/src/feature/rend/rendclient.c b/src/feature/rend/rendclient.c
index 4ca783c7c..5bdd4d453 100644
--- a/src/feature/rend/rendclient.c
+++ b/src/feature/rend/rendclient.c
@@ -17,7 +17,7 @@
 #include "core/or/connection_edge.h"
 #include "core/or/relay.h"
 #include "feature/client/circpathbias.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirclient/dirclient.h"
 #include "feature/dircommon/directory.h"
 #include "feature/hs/hs_circuit.h"
@@ -403,14 +403,23 @@ rend_client_introduction_acked(origin_circuit_t *circ,
     } else {
       log_info(LD_REND,"...Found no rend circ. Dropping on the floor.");
     }
+    /* Save the rend data digest to a temporary object so that we don't access
+     * it after we mark the circuit for close. */
+    const uint8_t *rend_digest_tmp = NULL;
+    size_t digest_len;
+    uint8_t *cached_rend_digest = NULL;
+    rend_digest_tmp = rend_data_get_pk_digest(circ->rend_data, &digest_len);
+    cached_rend_digest = tor_malloc_zero(digest_len);
+    memcpy(cached_rend_digest, rend_digest_tmp, digest_len);
+
     /* close the circuit: we won't need it anymore. */
     circuit_change_purpose(TO_CIRCUIT(circ),
                            CIRCUIT_PURPOSE_C_INTRODUCE_ACKED);
     circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED);
 
     /* close any other intros launched in parallel */
-    rend_client_close_other_intros(rend_data_get_pk_digest(circ->rend_data,
-                                                           NULL));
+    rend_client_close_other_intros(cached_rend_digest);
+    tor_free(cached_rend_digest); /* free the temporary digest */
   } else {
     /* It's a NAK; the introduction point didn't relay our request. */
     circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_INTRODUCING);
@@ -469,16 +478,19 @@ directory_get_from_hs_dir(const char *desc_id,
 
   /* Automatically pick an hs dir if none given. */
   if (!rs_hsdir) {
+    bool rate_limited = false;
+
     /* Determine responsible dirs. Even if we can't get all we want, work with
      * the ones we have. If it's empty, we'll notice in hs_pick_hsdir(). */
     smartlist_t *responsible_dirs = smartlist_new();
     hid_serv_get_responsible_directories(responsible_dirs, desc_id);
 
-    hs_dir = hs_pick_hsdir(responsible_dirs, desc_id_base32);
+    hs_dir = hs_pick_hsdir(responsible_dirs, desc_id_base32, &rate_limited);
     if (!hs_dir) {
       /* No suitable hs dir can be found, stop right now. */
-      control_event_hsv2_descriptor_failed(rend_query, NULL,
-                                           "QUERY_NO_HSDIR");
+      const char *query_response = (rate_limited) ? "QUERY_RATE_LIMITED" :
+                                                    "QUERY_NO_HSDIR";
+      control_event_hsv2_descriptor_failed(rend_query, NULL, query_response);
       control_event_hs_descriptor_content(rend_data_get_address(rend_query),
                                           desc_id_base32, NULL, NULL);
       return 0;
diff --git a/src/feature/rend/rendcommon.c b/src/feature/rend/rendcommon.c
index de48af795..777de2984 100644
--- a/src/feature/rend/rendcommon.c
+++ b/src/feature/rend/rendcommon.c
@@ -15,7 +15,7 @@
 #include "core/or/circuitlist.h"
 #include "core/or/circuituse.h"
 #include "app/config/config.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/crypt_ops/crypto_util.h"
 #include "feature/hs/hs_client.h"
@@ -171,9 +171,10 @@ rend_compute_v2_desc_id(char *desc_id_out, const char *service_id,
   }
   /* Convert service ID to binary. */
   if (base32_decode(service_id_binary, REND_SERVICE_ID_LEN,
-                    service_id, REND_SERVICE_ID_LEN_BASE32) < 0) {
+                    service_id, REND_SERVICE_ID_LEN_BASE32) !=
+      REND_SERVICE_ID_LEN) {
     log_warn(LD_REND, "Could not compute v2 descriptor ID: "
-                      "Illegal characters in service ID: %s",
+                      "Illegal characters or wrong length for service ID: %s",
              safe_str_client(service_id));
     return -1;
   }
diff --git a/src/feature/rend/rendparse.c b/src/feature/rend/rendparse.c
index abd0feb44..a98cb3ad8 100644
--- a/src/feature/rend/rendparse.c
+++ b/src/feature/rend/rendparse.c
@@ -143,8 +143,9 @@ rend_parse_v2_service_descriptor(rend_service_descriptor_t **parsed_out,
     goto err;
   }
   if (base32_decode(desc_id_out, DIGEST_LEN,
-                    tok->args[0], REND_DESC_ID_V2_LEN_BASE32) < 0) {
-    log_warn(LD_REND, "Descriptor ID contains illegal characters: %s",
+                    tok->args[0], REND_DESC_ID_V2_LEN_BASE32) != DIGEST_LEN) {
+    log_warn(LD_REND,
+             "Descriptor ID has wrong length or illegal characters: %s",
              tok->args[0]);
     goto err;
   }
@@ -174,8 +175,10 @@ rend_parse_v2_service_descriptor(rend_service_descriptor_t **parsed_out,
     log_warn(LD_REND, "Invalid secret ID part: '%s'", tok->args[0]);
     goto err;
   }
-  if (base32_decode(secret_id_part, DIGEST_LEN, tok->args[0], 32) < 0) {
-    log_warn(LD_REND, "Secret ID part contains illegal characters: %s",
+  if (base32_decode(secret_id_part, DIGEST_LEN, tok->args[0], 32) !=
+      DIGEST_LEN) {
+    log_warn(LD_REND,
+             "Secret ID part has wrong length or illegal characters: %s",
              tok->args[0]);
     goto err;
   }
@@ -429,8 +432,10 @@ rend_parse_introduction_points(rend_service_descriptor_t *parsed,
     /* Parse identifier. */
     tok = find_by_keyword(tokens, R_IPO_IDENTIFIER);
     if (base32_decode(info->identity_digest, DIGEST_LEN,
-                      tok->args[0], REND_INTRO_POINT_ID_LEN_BASE32) < 0) {
-      log_warn(LD_REND, "Identity digest contains illegal characters: %s",
+                      tok->args[0], REND_INTRO_POINT_ID_LEN_BASE32) !=
+        DIGEST_LEN) {
+      log_warn(LD_REND,
+               "Identity digest has wrong length or illegal characters: %s",
                tok->args[0]);
       rend_intro_point_free(intro);
       goto err;
diff --git a/src/feature/rend/rendparse.h b/src/feature/rend/rendparse.h
index 0cef931e9..b1ccce9b6 100644
--- a/src/feature/rend/rendparse.h
+++ b/src/feature/rend/rendparse.h
@@ -29,4 +29,4 @@ int rend_parse_introduction_points(rend_service_descriptor_t *parsed,
                                    size_t intro_points_encoded_size);
 int rend_parse_client_keys(strmap_t *parsed_clients, const char *str);
 
-#endif
+#endif /* !defined(TOR_REND_PARSE_H) */
diff --git a/src/feature/rend/rendservice.c b/src/feature/rend/rendservice.c
index 5ee084b0b..119a6f9c8 100644
--- a/src/feature/rend/rendservice.c
+++ b/src/feature/rend/rendservice.c
@@ -18,8 +18,9 @@
 #include "core/or/circuituse.h"
 #include "core/or/policies.h"
 #include "core/or/relay.h"
+#include "core/or/crypt_path.h"
 #include "feature/client/circpathbias.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/dirclient/dirclient.h"
 #include "feature/dircommon/directory.h"
 #include "feature/hs/hs_common.h"
@@ -2122,8 +2123,12 @@ rend_service_receive_introduction(origin_circuit_t *circuit,
     int flags = CIRCLAUNCH_NEED_CAPACITY | CIRCLAUNCH_IS_INTERNAL;
     if (circ_needs_uptime) flags |= CIRCLAUNCH_NEED_UPTIME;
     /* A Single Onion Service only uses a direct connection if its
-     * firewall rules permit direct connections to the address. */
-    if (rend_service_use_direct_connection(options, rp)) {
+     * firewall rules permit direct connections to the address.
+     *
+     * We only use a one-hop path on the first attempt. If the first attempt
+     * fails, we use a 3-hop path for reachability / reliability.
+     * See the comment in rend_service_relauch_rendezvous() for details. */
+    if (rend_service_use_direct_connection(options, rp) && i == 0) {
       flags = flags | CIRCLAUNCH_ONEHOP_TUNNEL;
     }
     launched = circuit_launch_by_extend_info(
@@ -2163,7 +2168,7 @@ rend_service_receive_introduction(origin_circuit_t *circuit,
 
   cpath->rend_dh_handshake_state = dh;
   dh = NULL;
-  if (circuit_init_cpath_crypto(cpath,
+  if (cpath_init_circuit_crypto(cpath,
                                 keys+DIGEST_LEN, sizeof(keys)-DIGEST_LEN,
                                 1, 0)<0)
     goto err;
@@ -3012,6 +3017,10 @@ rend_service_relaunch_rendezvous(origin_circuit_t *oldcirc)
 {
   origin_circuit_t *newcirc;
   cpath_build_state_t *newstate, *oldstate;
+  const char *rend_pk_digest;
+  rend_service_t *service = NULL;
+
+  int flags = CIRCLAUNCH_NEED_CAPACITY | CIRCLAUNCH_IS_INTERNAL;
 
   tor_assert(oldcirc->base_.purpose == CIRCUIT_PURPOSE_S_CONNECT_REND);
   oldstate = oldcirc->build_state;
@@ -3026,13 +3035,31 @@ rend_service_relaunch_rendezvous(origin_circuit_t *oldcirc)
   log_info(LD_REND,"Reattempting rendezvous circuit to '%s'",
            safe_str(extend_info_describe(oldstate->chosen_exit)));
 
+  /* Look up the service. */
+  rend_pk_digest = (char *) rend_data_get_pk_digest(oldcirc->rend_data, NULL);
+  service = rend_service_get_by_pk_digest(rend_pk_digest);
+
+  if (!service) {
+    char serviceid[REND_SERVICE_ID_LEN_BASE32+1];
+    base32_encode(serviceid, REND_SERVICE_ID_LEN_BASE32+1,
+                  rend_pk_digest, REND_SERVICE_ID_LEN);
+
+    log_warn(LD_BUG, "Internal error: Trying to relaunch a rendezvous circ "
+                     "for an unrecognized service %s.",
+                     safe_str_client(serviceid));
+    return;
+  }
+
+  if (hs_service_requires_uptime_circ(service->ports)) {
+    flags |= CIRCLAUNCH_NEED_UPTIME;
+  }
+
   /* You'd think Single Onion Services would want to retry the rendezvous
    * using a direct connection. But if it's blocked by a firewall, or the
    * service is IPv6-only, or the rend point avoiding becoming a one-hop
    * proxy, we need a 3-hop connection. */
   newcirc = circuit_launch_by_extend_info(CIRCUIT_PURPOSE_S_CONNECT_REND,
-                            oldstate->chosen_exit,
-                            CIRCLAUNCH_NEED_CAPACITY|CIRCLAUNCH_IS_INTERNAL);
+                            oldstate->chosen_exit, flags);
 
   if (!newcirc) {
     log_warn(LD_REND,"Couldn't relaunch rendezvous circuit to '%s'.",
@@ -3063,8 +3090,15 @@ rend_service_launch_establish_intro(rend_service_t *service,
   extend_info_t *launch_ei = intro->extend_info;
   extend_info_t *direct_ei = NULL;
 
-  /* Are we in single onion mode? */
-  if (rend_service_allow_non_anonymous_connection(options)) {
+  /* Are we in single onion mode?
+   *
+   * We only use a one-hop path on the first attempt. If the first attempt
+   * fails, we use a 3-hop path for reachability / reliability.
+   * (Unlike v3, retries is incremented by the caller after it calls this
+   * function.)
+   */
+  if (rend_service_allow_non_anonymous_connection(options) &&
+      intro->circuit_retries == 0) {
     /* Do we have a descriptor for the node?
      * We've either just chosen it from the consensus, or we've just reviewed
      * our intro points to see which ones are still valid, and deleted the ones
@@ -3525,7 +3559,7 @@ rend_service_rendezvous_has_opened(origin_circuit_t *circuit)
   hop->package_window = circuit_initial_package_window();
   hop->deliver_window = CIRCWINDOW_START;
 
-  onion_append_to_cpath(&circuit->cpath, hop);
+  cpath_extend_linked_list(&circuit->cpath, hop);
   circuit->build_state->pending_final_cpath = NULL; /* prevent double-free */
 
   /* Change the circuit purpose. */
@@ -4205,6 +4239,7 @@ rend_consider_services_intro_points(time_t now)
        * directly ourselves. */
       intro->extend_info = extend_info_from_node(node, 0);
       if (BUG(intro->extend_info == NULL)) {
+        tor_free(intro);
         break;
       }
       intro->intro_key = crypto_pk_new();
diff --git a/src/feature/stats/geoip_stats.c b/src/feature/stats/geoip_stats.c
index 5119da19a..6fb21f4f7 100644
--- a/src/feature/stats/geoip_stats.c
+++ b/src/feature/stats/geoip_stats.c
@@ -32,7 +32,7 @@
 #include "ht.h"
 #include "lib/buf/buffers.h"
 #include "app/config/config.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/client/dnsserv.h"
 #include "core/or/dos.h"
 #include "lib/geoip/geoip.h"
diff --git a/src/feature/stats/predict_ports.h b/src/feature/stats/predict_ports.h
index 272344da2..45b206c23 100644
--- a/src/feature/stats/predict_ports.h
+++ b/src/feature/stats/predict_ports.h
@@ -27,4 +27,4 @@ int rep_hist_circbuilding_dormant(time_t now);
 int predicted_ports_prediction_time_remaining(time_t now);
 void predicted_ports_free_all(void);
 
-#endif
+#endif /* !defined(TOR_PREDICT_PORTS_H) */
diff --git a/src/feature/stats/rephist.h b/src/feature/stats/rephist.h
index 3accc8c61..0d7294638 100644
--- a/src/feature/stats/rephist.h
+++ b/src/feature/stats/rephist.h
@@ -103,7 +103,7 @@ typedef struct bw_array_t bw_array_t;
 STATIC uint64_t find_largest_max(bw_array_t *b);
 STATIC void commit_max(bw_array_t *b);
 STATIC void advance_obs(bw_array_t *b);
-#endif
+#endif /* defined(REPHIST_PRIVATE) */
 
 /**
  * Represents the type of a cell for padding accounting
diff --git a/src/include.am b/src/include.am
index 9070a69a0..77c126ba4 100644
--- a/src/include.am
+++ b/src/include.am
@@ -8,6 +8,7 @@ include src/lib/compress/include.am
 include src/lib/container/include.am
 include src/lib/crypt_ops/include.am
 include src/lib/defs/include.am
+include src/lib/dispatch/include.am
 include src/lib/encoding/include.am
 include src/lib/evloop/include.am
 include src/lib/fdio/include.am
@@ -24,6 +25,7 @@ include src/lib/malloc/include.am
 include src/lib/net/include.am
 include src/lib/osinfo/include.am
 include src/lib/process/include.am
+include src/lib/pubsub/include.am
 include src/lib/sandbox/include.am
 include src/lib/string/include.am
 include src/lib/subsys/include.am
diff --git a/src/lib/arch/bytes.h b/src/lib/arch/bytes.h
index fa82241b2..b8b628813 100644
--- a/src/lib/arch/bytes.h
+++ b/src/lib/arch/bytes.h
@@ -129,7 +129,7 @@ tor_ntohll(uint64_t a)
 {
   return a;
 }
-#else
+#else /* !(defined(WORDS_BIGENDIAN)) */
 static inline uint16_t
 tor_htons(uint16_t a)
 {
@@ -177,6 +177,6 @@ tor_ntohll(uint64_t a)
 {
   return tor_htonll(a);
 }
-#endif
+#endif /* defined(WORDS_BIGENDIAN) */
 
-#endif
+#endif /* !defined(TOR_BYTES_H) */
diff --git a/src/lib/arch/include.am b/src/lib/arch/include.am
index f92ee9222..c5926c633 100644
--- a/src/lib/arch/include.am
+++ b/src/lib/arch/include.am
@@ -1,3 +1,4 @@
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS += \
 	src/lib/arch/bytes.h
diff --git a/src/lib/buf/include.am b/src/lib/buf/include.am
index 3338c3dbd..27430d1d3 100644
--- a/src/lib/buf/include.am
+++ b/src/lib/buf/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-buf-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_buf_a_SOURCES =			\
 	src/lib/buf/buffers.c
 
@@ -13,5 +14,6 @@ src_lib_libtor_buf_testing_a_SOURCES = \
 src_lib_libtor_buf_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_buf_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=				\
 	src/lib/buf/buffers.h
diff --git a/src/lib/cc/compat_compiler.h b/src/lib/cc/compat_compiler.h
index 3a0f30718..a8d159321 100644
--- a/src/lib/cc/compat_compiler.h
+++ b/src/lib/cc/compat_compiler.h
@@ -217,4 +217,16 @@
 /** Macro: Yields the number of elements in array x. */
 #define ARRAY_LENGTH(x) ((sizeof(x)) / sizeof(x[0]))
 
-#endif /* !defined(TOR_COMPAT_H) */
+/**
+ * "Eat" a semicolon that somebody puts at the end of a top-level macro.
+ *
+ * Frequently, we want to declare a macro that people will use at file scope,
+ * and we want to allow people to put a semicolon after the macro.
+ *
+ * This declaration of a struct can be repeated any number of times, and takes
+ * a trailing semicolon afterwards.
+ **/
+#define EAT_SEMICOLON                                   \
+  struct dummy_semicolon_eater__
+
+#endif /* !defined(TOR_COMPAT_COMPILER_H) */
diff --git a/src/lib/cc/ctassert.h b/src/lib/cc/ctassert.h
index e42976360..bedf0b83a 100644
--- a/src/lib/cc/ctassert.h
+++ b/src/lib/cc/ctassert.h
@@ -22,7 +22,7 @@
 /* If C11 is available, just use _Static_assert.  */
 #define CTASSERT(x) _Static_assert((x), #x)
 
-#else
+#else /* !(__STDC_VERSION__ >= 201112L) */
 
 /*
  * If C11 is not available, expand __COUNTER__, or __INCLUDE_LEVEL__
@@ -42,12 +42,12 @@
 #else
 /* hope it's unique enough */
 #define CTASSERT(x) CTASSERT_EXPN((x), l, __LINE__)
-#endif
+#endif /* defined(__COUNTER__) || ... */
 
 #define CTASSERT_EXPN(x, a, b) CTASSERT_DECL(x, a, b)
 #define CTASSERT_DECL(x, a, b) \
   typedef char tor_ctassert_##a##_##b[(x) ? 1 : -1] ATTR_UNUSED
 
-#endif
+#endif /* __STDC_VERSION__ >= 201112L */
 
 #endif /* !defined(TOR_CTASSERT_H) */
diff --git a/src/lib/cc/include.am b/src/lib/cc/include.am
index 52cf8a9f7..1aa722dd8 100644
--- a/src/lib/cc/include.am
+++ b/src/lib/cc/include.am
@@ -1,4 +1,5 @@
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS += \
 	src/lib/cc/compat_compiler.h \
 	src/lib/cc/ctassert.h \
diff --git a/src/lib/cc/torint.h b/src/lib/cc/torint.h
index c9b2d329f..523f378ed 100644
--- a/src/lib/cc/torint.h
+++ b/src/lib/cc/torint.h
@@ -96,9 +96,9 @@ typedef int32_t ssize_t;
 #  else
 #    define TOR_PRIuSZ PRIu32
 #  endif
-#else
+#else /* !(defined(_WIN32)) */
 #  define TOR_PRIuSZ "zu"
-#endif
+#endif /* defined(_WIN32) */
 
 #ifdef _WIN32
 #  ifdef _WIN64
@@ -106,9 +106,9 @@ typedef int32_t ssize_t;
 #  else
 #    define TOR_PRIdSZ PRId32
 #  endif
-#else
+#else /* !(defined(_WIN32)) */
 #  define TOR_PRIdSZ "zd"
-#endif
+#endif /* defined(_WIN32) */
 
 #ifndef SSIZE_MAX
 #if (SIZEOF_SIZE_T == 4)
@@ -125,4 +125,13 @@ typedef int32_t ssize_t;
 /** Any size_t larger than this amount is likely to be an underflow. */
 #define SIZE_T_CEILING  ((size_t)(SSIZE_MAX-16))
 
+#if SIZEOF_INT > SIZEOF_VOID_P
+#error "sizeof(int) > sizeof(void *) - Tor cannot be built on this platform!"
+#endif
+
+#if SIZEOF_UNSIGNED_INT > SIZEOF_VOID_P
+#error "sizeof(unsigned int) > sizeof(void *) - Tor cannot be built on this \
+platform!"
+#endif
+
 #endif /* !defined(TOR_TORINT_H) */
diff --git a/src/lib/compress/compress_zstd.c b/src/lib/compress/compress_zstd.c
index 45d0d4d60..a99ea67e0 100644
--- a/src/lib/compress/compress_zstd.c
+++ b/src/lib/compress/compress_zstd.c
@@ -25,7 +25,7 @@
  * all invocations of zstd's static-only functions in a check to make sure
  * that the compile-time version matches the run-time version. */
 #define ZSTD_STATIC_LINKING_ONLY
-#endif
+#endif /* defined(ENABLE_ZSTD_ADVANCED_APIS) */
 
 #ifdef HAVE_ZSTD
 #ifdef HAVE_CFLAG_WUNUSED_CONST_VARIABLE
@@ -35,7 +35,7 @@ DISABLE_GCC_WARNING(unused-const-variable)
 #ifdef HAVE_CFLAG_WUNUSED_CONST_VARIABLE
 ENABLE_GCC_WARNING(unused-const-variable)
 #endif
-#endif
+#endif /* defined(HAVE_ZSTD) */
 
 /** Total number of bytes allocated for Zstandard state. */
 static atomic_counter_t total_zstd_allocation;
@@ -77,7 +77,7 @@ tor_zstd_format_version(char *buf, size_t buflen, unsigned version_number)
                version_number / 100 % 100,
                version_number % 100);
 }
-#endif
+#endif /* defined(HAVE_ZSTD) */
 
 #define VERSION_STR_MAX_LEN 16 /* more than enough space for 99.99.99 */
 
@@ -125,9 +125,9 @@ tor_zstd_can_use_static_apis(void)
   }
 #endif
   return (ZSTD_VERSION_NUMBER == ZSTD_versionNumber());
-#else
+#else /* !(defined(ZSTD_STATIC_LINKING_ONLY) && defined(HAVE_ZSTD)) */
   return 0;
-#endif
+#endif /* defined(ZSTD_STATIC_LINKING_ONLY) && defined(HAVE_ZSTD) */
 }
 
 /** Internal Zstandard state for incremental compression/decompression.
@@ -237,7 +237,7 @@ tor_zstd_state_size_precalc(int compress, int preset)
 #endif
     }
   }
-#endif
+#endif /* defined(ZSTD_STATIC_LINKING_ONLY) */
   return tor_zstd_state_size_precalc_fake(compress, preset);
 }
 #endif /* defined(HAVE_ZSTD) */
@@ -527,7 +527,7 @@ tor_zstd_warn_if_version_mismatched(void)
              "For safety, we'll avoid using advanced zstd functionality.",
              header_version, runtime_version);
   }
-#endif
+#endif /* defined(HAVE_ZSTD) && defined(ENABLE_ZSTD_ADVANCED_APIS) */
 }
 
 #ifdef TOR_UNIT_TESTS
@@ -538,4 +538,4 @@ tor_zstd_set_static_apis_disabled_for_testing(int disabled)
 {
   static_apis_disable_for_testing = disabled;
 }
-#endif
+#endif /* defined(TOR_UNIT_TESTS) */
diff --git a/src/lib/compress/include.am b/src/lib/compress/include.am
index b95277957..60dd447d4 100644
--- a/src/lib/compress/include.am
+++ b/src/lib/compress/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-compress-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_compress_a_SOURCES =		\
 	src/lib/compress/compress.c		\
 	src/lib/compress/compress_buf.c		\
@@ -18,6 +19,7 @@ src_lib_libtor_compress_testing_a_SOURCES = \
 src_lib_libtor_compress_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_compress_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS	+=				\
 	src/lib/compress/compress.h		\
 	src/lib/compress/compress_lzma.h	\
diff --git a/src/lib/container/bitarray.h b/src/lib/container/bitarray.h
index 910d5fea6..45992796a 100644
--- a/src/lib/container/bitarray.h
+++ b/src/lib/container/bitarray.h
@@ -83,4 +83,4 @@ bitarray_is_set(bitarray_t *b, int bit)
   return b[bit >> BITARRAY_SHIFT] & (1u << (bit & BITARRAY_MASK));
 }
 
-#endif /* !defined(TOR_CONTAINER_H) */
+#endif /* !defined(TOR_BITARRAY_H) */
diff --git a/src/lib/container/include.am b/src/lib/container/include.am
index 032e4033d..00d7b8e58 100644
--- a/src/lib/container/include.am
+++ b/src/lib/container/include.am
@@ -5,9 +5,11 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-container-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_container_a_SOURCES =			\
 	src/lib/container/bloomfilt.c			\
 	src/lib/container/map.c				\
+	src/lib/container/namemap.c			\
 	src/lib/container/order.c			\
 	src/lib/container/smartlist.c
 
@@ -16,10 +18,13 @@ src_lib_libtor_container_testing_a_SOURCES = \
 src_lib_libtor_container_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_container_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/container/bitarray.h			\
 	src/lib/container/bloomfilt.h			\
 	src/lib/container/handles.h			\
 	src/lib/container/map.h				\
+	src/lib/container/namemap.h			\
+	src/lib/container/namemap_st.h			\
 	src/lib/container/order.h			\
 	src/lib/container/smartlist.h
diff --git a/src/lib/container/map.h b/src/lib/container/map.h
index d61b1ec18..9da1d3072 100644
--- a/src/lib/container/map.h
+++ b/src/lib/container/map.h
@@ -258,4 +258,4 @@ void* strmap_remove_lc(strmap_t *map, const char *key);
     return digestmap_iter_done((digestmap_iter_t*)iter);                \
   }
 
-#endif /* !defined(TOR_CONTAINER_H) */
+#endif /* !defined(TOR_MAP_H) */
diff --git a/src/lib/container/namemap.c b/src/lib/container/namemap.c
new file mode 100644
index 000000000..a90057b32
--- /dev/null
+++ b/src/lib/container/namemap.c
@@ -0,0 +1,184 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "orconfig.h"
+#include "lib/container/smartlist.h"
+#include "lib/container/namemap.h"
+#include "lib/container/namemap_st.h"
+#include "lib/log/util_bug.h"
+#include "lib/malloc/malloc.h"
+#include "lib/string/printf.h"
+
+#include "ext/siphash.h"
+
+#include <string.h>
+
+/** Helper for namemap hashtable implementation: compare two entries. */
+static inline int
+mapped_name_eq(const mapped_name_t *a, const mapped_name_t *b)
+{
+  return !strcmp(a->name, b->name);
+}
+
+/** Helper for namemap hashtable implementation: hash an entry. */
+static inline unsigned
+mapped_name_hash(const mapped_name_t *a)
+{
+  return (unsigned) siphash24g(a->name, strlen(a->name));
+}
+
+HT_PROTOTYPE(namemap_ht, mapped_name_t, node, mapped_name_hash,
+             mapped_name_eq)
+HT_GENERATE2(namemap_ht, mapped_name_t, node, mapped_name_hash,
+             mapped_name_eq, 0.6, tor_reallocarray_, tor_free_)
+
+/** Set up an uninitialized <b>map</b>. */
+void
+namemap_init(namemap_t *map)
+{
+  memset(map, 0, sizeof(*map));
+  HT_INIT(namemap_ht, &map->ht);
+  map->names = smartlist_new();
+}
+
+/** Return the name that <b>map</b> associates with a given <b>id</b>, or
+ * NULL if there is no such name. */
+const char *
+namemap_get_name(const namemap_t *map, unsigned id)
+{
+  if (map->names && id < (unsigned)smartlist_len(map->names)) {
+    mapped_name_t *name = smartlist_get(map->names, (int)id);
+    return name->name;
+  } else {
+    return NULL;
+  }
+}
+
+/**
+ * Return the name that <b>map</b> associates with a given <b>id</b>, or a
+ * pointer to a statically allocated string describing the value of <b>id</b>
+ * if no such name exists.
+ **/
+const char *
+namemap_fmt_name(const namemap_t *map, unsigned id)
+{
+  static char buf[32];
+
+  const char *name = namemap_get_name(map, id);
+  if (name)
+    return name;
+
+  tor_snprintf(buf, sizeof(buf), "{%u}", id);
+
+  return buf;
+}
+
+/**
+ * Helper: As namemap_get_id(), but requires that <b>name</b> is
+ * <b>namelen</b> charaters long, and that <b>namelen</b> is no more than
+ * MAX_NAMEMAP_NAME_LEN.
+ */
+static unsigned
+namemap_get_id_unchecked(const namemap_t *map,
+                         const char *name,
+                         size_t namelen)
+{
+  union {
+    mapped_name_t n;
+    char storage[MAX_NAMEMAP_NAME_LEN + sizeof(mapped_name_t) + 1];
+  } u;
+  memcpy(u.n.name, name, namelen);
+  u.n.name[namelen] = 0;
+  const mapped_name_t *found = HT_FIND(namemap_ht, &map->ht, &u.n);
+  if (found) {
+    tor_assert(map->names);
+    tor_assert(smartlist_get(map->names, found->intval) == found);
+    return found->intval;
+  }
+
+  return NAMEMAP_ERR;
+}
+
+/**
+ * Return the identifier currently associated by <b>map</b> with the name
+ * <b>name</b>, or NAMEMAP_ERR if no such identifier exists.
+ **/
+unsigned
+namemap_get_id(const namemap_t *map,
+               const char *name)
+{
+  size_t namelen = strlen(name);
+  if (namelen > MAX_NAMEMAP_NAME_LEN) {
+    return NAMEMAP_ERR;
+  }
+
+  return namemap_get_id_unchecked(map, name, namelen);
+}
+
+/**
+ * Return the identifier associated by <b>map</b> with the name
+ * <b>name</b>, allocating a new identifier in <b>map</b> if none exists.
+ *
+ * Return NAMEMAP_ERR if <b>name</b> is too long, or if there are no more
+ * identifiers we can allocate.
+ **/
+unsigned
+namemap_get_or_create_id(namemap_t *map,
+                         const char *name)
+{
+  size_t namelen = strlen(name);
+  if (namelen > MAX_NAMEMAP_NAME_LEN) {
+    return NAMEMAP_ERR;
+  }
+
+  if (PREDICT_UNLIKELY(map->names == NULL))
+    map->names = smartlist_new();
+
+  unsigned found = namemap_get_id_unchecked(map, name, namelen);
+  if (found != NAMEMAP_ERR)
+    return found;
+
+  unsigned new_id = (unsigned)smartlist_len(map->names);
+  if (new_id == NAMEMAP_ERR)
+    return NAMEMAP_ERR; /* Can't allocate any more. */
+
+  mapped_name_t *insert = tor_malloc_zero(
+                       offsetof(mapped_name_t, name) + namelen + 1);
+  memcpy(insert->name, name, namelen+1);
+  insert->intval = new_id;
+
+  HT_INSERT(namemap_ht, &map->ht, insert);
+  smartlist_add(map->names, insert);
+
+  return new_id;
+}
+
+/** Return the number of entries in 'names' */
+size_t
+namemap_get_size(const namemap_t *map)
+{
+  if (PREDICT_UNLIKELY(map->names == NULL))
+    return 0;
+
+  return smartlist_len(map->names);
+}
+
+/**
+ * Release all storage held in <b>map</b>.
+ */
+void
+namemap_clear(namemap_t *map)
+{
+  if (!map)
+    return;
+
+  HT_CLEAR(namemap_ht, &map->ht);
+  if (map->names) {
+    SMARTLIST_FOREACH(map->names, mapped_name_t *, n,
+                      tor_free(n));
+    smartlist_free(map->names);
+  }
+  memset(map, 0, sizeof(*map));
+}
diff --git a/src/lib/container/namemap.h b/src/lib/container/namemap.h
new file mode 100644
index 000000000..b96bc13f3
--- /dev/null
+++ b/src/lib/container/namemap.h
@@ -0,0 +1,35 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_NAMEMAP_H
+#define TOR_NAMEMAP_H
+
+/**
+ * \file namemap.h
+ *
+ * \brief Header for namemap.c
+ **/
+
+#include "lib/cc/compat_compiler.h"
+#include "ext/ht.h"
+
+#include <stddef.h>
+
+typedef struct namemap_t namemap_t;
+
+/** Returned in place of an identifier when an error occurs. */
+#define NAMEMAP_ERR UINT_MAX
+
+void namemap_init(namemap_t *map);
+const char *namemap_get_name(const namemap_t *map, unsigned id);
+const char *namemap_fmt_name(const namemap_t *map, unsigned id);
+unsigned namemap_get_id(const namemap_t *map,
+                        const char *name);
+unsigned namemap_get_or_create_id(namemap_t *map,
+                                  const char *name);
+size_t namemap_get_size(const namemap_t *map);
+void namemap_clear(namemap_t *map);
+
+#endif /* !defined(TOR_NAMEMAP_H) */
diff --git a/src/lib/container/namemap_st.h b/src/lib/container/namemap_st.h
new file mode 100644
index 000000000..5008fd585
--- /dev/null
+++ b/src/lib/container/namemap_st.h
@@ -0,0 +1,34 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef NAMEMAP_ST_H
+#define NAMEMAP_ST_H
+
+#include "lib/cc/compat_compiler.h"
+#include "ext/ht.h"
+
+struct smartlist_t;
+
+/** Longest allowed name that's allowed in a namemap_t. */
+#define MAX_NAMEMAP_NAME_LEN 128
+
+/** An entry inside a namemap_t. Maps a string to a numeric identifier. */
+typedef struct mapped_name_t {
+  HT_ENTRY(mapped_name_t) node;
+  unsigned intval;
+  char name[FLEXIBLE_ARRAY_MEMBER];
+} mapped_name_t;
+
+/** A structure that allocates small numeric identifiers for names and maps
+ * back and forth between them.  */
+struct namemap_t {
+  HT_HEAD(namemap_ht, mapped_name_t) ht;
+  struct smartlist_t *names;
+};
+
+/** Macro to initialize a namemap. */
+#define NAMEMAP_INIT() { HT_INITIALIZER(), NULL }
+
+#endif /* !defined(NAMEMAP_ST_H) */
diff --git a/src/lib/container/order.h b/src/lib/container/order.h
index a176d6d8a..3f2fd054a 100644
--- a/src/lib/container/order.h
+++ b/src/lib/container/order.h
@@ -57,4 +57,4 @@ third_quartile_uint32(uint32_t *array, int n_elements)
   return find_nth_uint32(array, n_elements, (n_elements*3)/4);
 }
 
-#endif /* !defined(TOR_CONTAINER_H) */
+#endif /* !defined(TOR_ORDER_H) */
diff --git a/src/lib/container/smartlist.h b/src/lib/container/smartlist.h
index 77682db03..81b015143 100644
--- a/src/lib/container/smartlist.h
+++ b/src/lib/container/smartlist.h
@@ -165,4 +165,4 @@ char *smartlist_join_strings2(smartlist_t *sl, const char *join,
   }                                             \
   STMT_END
 
-#endif /* !defined(TOR_CONTAINER_H) */
+#endif /* !defined(TOR_SMARTLIST_H) */
diff --git a/src/lib/crypt_ops/crypto_cipher.h b/src/lib/crypt_ops/crypto_cipher.h
index cc4fbf7a4..88d63c1df 100644
--- a/src/lib/crypt_ops/crypto_cipher.h
+++ b/src/lib/crypt_ops/crypto_cipher.h
@@ -54,4 +54,4 @@ int crypto_cipher_decrypt_with_iv(const char *key,
                                   char *to, size_t tolen,
                                   const char *from, size_t fromlen);
 
-#endif /* !defined(TOR_CRYPTO_H) */
+#endif /* !defined(TOR_CRYPTO_CIPHER_H) */
diff --git a/src/lib/crypt_ops/crypto_curve25519.h b/src/lib/crypt_ops/crypto_curve25519.h
index 061a7a350..cd23169cd 100644
--- a/src/lib/crypt_ops/crypto_curve25519.h
+++ b/src/lib/crypt_ops/crypto_curve25519.h
@@ -76,8 +76,8 @@ STATIC int curve25519_basepoint_impl(uint8_t *output, const uint8_t *secret);
 
 int curve25519_public_from_base64(curve25519_public_key_t *pkey,
                                   const char *input);
-int curve25519_public_to_base64(char *output,
-                                const curve25519_public_key_t *pkey);
+void curve25519_public_to_base64(char *output,
+                                 const curve25519_public_key_t *pkey);
 
 void curve25519_set_impl_params(int use_ed);
 void curve25519_init(void);
diff --git a/src/lib/crypt_ops/crypto_dh_openssl.c b/src/lib/crypt_ops/crypto_dh_openssl.c
index 8c6388fd5..75cee1b59 100644
--- a/src/lib/crypt_ops/crypto_dh_openssl.c
+++ b/src/lib/crypt_ops/crypto_dh_openssl.c
@@ -34,7 +34,7 @@ static int tor_check_dh_key(int severity, const BIGNUM *bn);
 struct crypto_dh_t {
   DH *dh; /**< The openssl DH object */
 };
-#endif
+#endif /* !defined(ENABLE_NSS) */
 
 static DH *new_openssl_dh_from_params(BIGNUM *p, BIGNUM *g);
 
@@ -100,7 +100,7 @@ crypto_validate_dh_params(const BIGNUM *p, const BIGNUM *g)
     DH_free(dh);
   return ret;
 }
-#endif
+#endif /* 0 */
 
 /**
  * Helper: convert <b>hex<b> to a bignum, and return it.  Assert that the
@@ -202,7 +202,7 @@ crypto_dh_new(int dh_type)
     tor_free(res); // sets res to NULL.
   return res;
 }
-#endif
+#endif /* !defined(ENABLE_NSS) */
 
 /** Create and return a new openssl DH from a given prime and generator. */
 static DH *
@@ -461,7 +461,7 @@ crypto_dh_free_(crypto_dh_t *dh)
   DH_free(dh->dh);
   tor_free(dh);
 }
-#endif
+#endif /* !defined(ENABLE_NSS) */
 
 void
 crypto_dh_free_all_openssl(void)
diff --git a/src/lib/crypt_ops/crypto_digest.c b/src/lib/crypt_ops/crypto_digest.c
index 26f06c6c7..64a7d2d52 100644
--- a/src/lib/crypt_ops/crypto_digest.c
+++ b/src/lib/crypt_ops/crypto_digest.c
@@ -23,171 +23,6 @@
 
 #include "lib/arch/bytes.h"
 
-#ifdef ENABLE_NSS
-DISABLE_GCC_WARNING(strict-prototypes)
-#include <pk11pub.h>
-ENABLE_GCC_WARNING(strict-prototypes)
-#else
-
-#include "lib/crypt_ops/crypto_openssl_mgt.h"
-
-DISABLE_GCC_WARNING(redundant-decls)
-
-#include <openssl/hmac.h>
-#include <openssl/sha.h>
-
-ENABLE_GCC_WARNING(redundant-decls)
-#endif
-
-#ifdef ENABLE_NSS
-/**
- * Convert a digest_algorithm_t (used by tor) to a HashType (used by NSS).
- * On failure, return SEC_OID_UNKNOWN. */
-static SECOidTag
-digest_alg_to_nss_oid(digest_algorithm_t alg)
-{
-  switch (alg) {
-    case DIGEST_SHA1: return SEC_OID_SHA1;
-    case DIGEST_SHA256: return SEC_OID_SHA256;
-    case DIGEST_SHA512: return SEC_OID_SHA512;
-    case DIGEST_SHA3_256: /* Fall through */
-    case DIGEST_SHA3_512: /* Fall through */
-    default:
-      return SEC_OID_UNKNOWN;
-  }
-}
-
-/* Helper: get an unkeyed digest via pk11wrap */
-static int
-digest_nss_internal(SECOidTag alg,
-                    char *digest, unsigned len_out,
-                    const char *msg, size_t msg_len)
-{
-  if (alg == SEC_OID_UNKNOWN)
-    return -1;
-  tor_assert(msg_len <= UINT_MAX);
-
-  int rv = -1;
-  SECStatus s;
-  PK11Context *ctx = PK11_CreateDigestContext(alg);
-  if (!ctx)
-    return -1;
-
-  s = PK11_DigestBegin(ctx);
-  if (s != SECSuccess)
-    goto done;
-
-  s = PK11_DigestOp(ctx, (const unsigned char *)msg, (unsigned int)msg_len);
-  if (s != SECSuccess)
-    goto done;
-
-  unsigned int len = 0;
-  s = PK11_DigestFinal(ctx, (unsigned char *)digest, &len, len_out);
-  if (s != SECSuccess)
-    goto done;
-
-  rv = 0;
- done:
-  PK11_DestroyContext(ctx, PR_TRUE);
-  return rv;
-}
-
-/** True iff alg is implemented in our crypto library, and we want to use that
- * implementation */
-static bool
-library_supports_digest(digest_algorithm_t alg)
-{
-  switch (alg) {
-    case DIGEST_SHA1: /* Fall through */
-    case DIGEST_SHA256: /* Fall through */
-    case DIGEST_SHA512: /* Fall through */
-      return true;
-    case DIGEST_SHA3_256: /* Fall through */
-    case DIGEST_SHA3_512: /* Fall through */
-    default:
-      return false;
-  }
-}
-#endif
-
-/* Crypto digest functions */
-
-/** Compute the SHA1 digest of the <b>len</b> bytes on data stored in
- * <b>m</b>.  Write the DIGEST_LEN byte result into <b>digest</b>.
- * Return 0 on success, -1 on failure.
- */
-MOCK_IMPL(int,
-crypto_digest,(char *digest, const char *m, size_t len))
-{
-  tor_assert(m);
-  tor_assert(digest);
-#ifdef ENABLE_NSS
-  return digest_nss_internal(SEC_OID_SHA1, digest, DIGEST_LEN, m, len);
-#else
-  if (SHA1((const unsigned char*)m,len,(unsigned char*)digest) == NULL) {
-    return -1;
-  }
-#endif
-  return 0;
-}
-
-/** Compute a 256-bit digest of <b>len</b> bytes in data stored in <b>m</b>,
- * using the algorithm <b>algorithm</b>.  Write the DIGEST_LEN256-byte result
- * into <b>digest</b>.  Return 0 on success, -1 on failure. */
-int
-crypto_digest256(char *digest, const char *m, size_t len,
-                 digest_algorithm_t algorithm)
-{
-  tor_assert(m);
-  tor_assert(digest);
-  tor_assert(algorithm == DIGEST_SHA256 || algorithm == DIGEST_SHA3_256);
-
-  int ret = 0;
-  if (algorithm == DIGEST_SHA256) {
-#ifdef ENABLE_NSS
-    return digest_nss_internal(SEC_OID_SHA256, digest, DIGEST256_LEN, m, len);
-#else
-    ret = (SHA256((const uint8_t*)m,len,(uint8_t*)digest) != NULL);
-#endif
-  } else {
-    ret = (sha3_256((uint8_t *)digest, DIGEST256_LEN,(const uint8_t *)m, len)
-           > -1);
-  }
-
-  if (!ret)
-    return -1;
-  return 0;
-}
-
-/** Compute a 512-bit digest of <b>len</b> bytes in data stored in <b>m</b>,
- * using the algorithm <b>algorithm</b>.  Write the DIGEST_LEN512-byte result
- * into <b>digest</b>.  Return 0 on success, -1 on failure. */
-int
-crypto_digest512(char *digest, const char *m, size_t len,
-                 digest_algorithm_t algorithm)
-{
-  tor_assert(m);
-  tor_assert(digest);
-  tor_assert(algorithm == DIGEST_SHA512 || algorithm == DIGEST_SHA3_512);
-
-  int ret = 0;
-  if (algorithm == DIGEST_SHA512) {
-#ifdef ENABLE_NSS
-    return digest_nss_internal(SEC_OID_SHA512, digest, DIGEST512_LEN, m, len);
-#else
-    ret = (SHA512((const unsigned char*)m,len,(unsigned char*)digest)
-           != NULL);
-#endif
-  } else {
-    ret = (sha3_512((uint8_t*)digest, DIGEST512_LEN, (const uint8_t*)m, len)
-           > -1);
-  }
-
-  if (!ret)
-    return -1;
-  return 0;
-}
-
 /** Set the common_digests_t in <b>ds_out</b> to contain every digest on the
  * <b>len</b> bytes in <b>m</b> that we know how to compute.  Return 0 on
  * success, -1 on failure. */
@@ -267,485 +102,6 @@ crypto_digest_algorithm_get_length(digest_algorithm_t alg)
   }
 }
 
-/** Intermediate information about the digest of a stream of data. */
-struct crypto_digest_t {
-  digest_algorithm_t algorithm; /**< Which algorithm is in use? */
-   /** State for the digest we're using.  Only one member of the
-    * union is usable, depending on the value of <b>algorithm</b>. Note also
-    * that space for other members might not even be allocated!
-    */
-  union {
-#ifdef ENABLE_NSS
-    PK11Context *ctx;
-#else
-    SHA_CTX sha1; /**< state for SHA1 */
-    SHA256_CTX sha2; /**< state for SHA256 */
-    SHA512_CTX sha512; /**< state for SHA512 */
-#endif
-    keccak_state sha3; /**< state for SHA3-[256,512] */
-  } d;
-};
-
-#ifdef TOR_UNIT_TESTS
-
-digest_algorithm_t
-crypto_digest_get_algorithm(crypto_digest_t *digest)
-{
-  tor_assert(digest);
-
-  return digest->algorithm;
-}
-
-#endif /* defined(TOR_UNIT_TESTS) */
-
-/**
- * Return the number of bytes we need to malloc in order to get a
- * crypto_digest_t for <b>alg</b>, or the number of bytes we need to wipe
- * when we free one.
- */
-static size_t
-crypto_digest_alloc_bytes(digest_algorithm_t alg)
-{
-  /* Helper: returns the number of bytes in the 'f' field of 'st' */
-#define STRUCT_FIELD_SIZE(st, f) (sizeof( ((st*)0)->f ))
-  /* Gives the length of crypto_digest_t through the end of the field 'd' */
-#define END_OF_FIELD(f) (offsetof(crypto_digest_t, f) + \
-                         STRUCT_FIELD_SIZE(crypto_digest_t, f))
-  switch (alg) {
-#ifdef ENABLE_NSS
-    case DIGEST_SHA1: /* Fall through */
-    case DIGEST_SHA256: /* Fall through */
-    case DIGEST_SHA512:
-      return END_OF_FIELD(d.ctx);
-#else
-    case DIGEST_SHA1:
-      return END_OF_FIELD(d.sha1);
-    case DIGEST_SHA256:
-      return END_OF_FIELD(d.sha2);
-    case DIGEST_SHA512:
-      return END_OF_FIELD(d.sha512);
-#endif
-    case DIGEST_SHA3_256:
-    case DIGEST_SHA3_512:
-      return END_OF_FIELD(d.sha3);
-    default:
-      tor_assert(0); // LCOV_EXCL_LINE
-      return 0;      // LCOV_EXCL_LINE
-  }
-#undef END_OF_FIELD
-#undef STRUCT_FIELD_SIZE
-}
-
-/**
- * Internal function: create and return a new digest object for 'algorithm'.
- * Does not typecheck the algorithm.
- */
-static crypto_digest_t *
-crypto_digest_new_internal(digest_algorithm_t algorithm)
-{
-  crypto_digest_t *r = tor_malloc(crypto_digest_alloc_bytes(algorithm));
-  r->algorithm = algorithm;
-
-  switch (algorithm)
-    {
-#ifdef ENABLE_NSS
-    case DIGEST_SHA1: /* fall through */
-    case DIGEST_SHA256: /* fall through */
-    case DIGEST_SHA512:
-      r->d.ctx = PK11_CreateDigestContext(digest_alg_to_nss_oid(algorithm));
-      if (BUG(!r->d.ctx)) {
-        tor_free(r);
-        return NULL;
-      }
-      if (BUG(SECSuccess != PK11_DigestBegin(r->d.ctx))) {
-        crypto_digest_free(r);
-        return NULL;
-      }
-      break;
-#else
-    case DIGEST_SHA1:
-      SHA1_Init(&r->d.sha1);
-      break;
-    case DIGEST_SHA256:
-      SHA256_Init(&r->d.sha2);
-      break;
-    case DIGEST_SHA512:
-      SHA512_Init(&r->d.sha512);
-      break;
-#endif
-    case DIGEST_SHA3_256:
-      keccak_digest_init(&r->d.sha3, 256);
-      break;
-    case DIGEST_SHA3_512:
-      keccak_digest_init(&r->d.sha3, 512);
-      break;
-    default:
-      tor_assert_unreached();
-    }
-
-  return r;
-}
-
-/** Allocate and return a new digest object to compute SHA1 digests.
- */
-crypto_digest_t *
-crypto_digest_new(void)
-{
-  return crypto_digest_new_internal(DIGEST_SHA1);
-}
-
-/** Allocate and return a new digest object to compute 256-bit digests
- * using <b>algorithm</b>.
- *
- * C_RUST_COUPLED: `external::crypto_digest::crypto_digest256_new`
- * C_RUST_COUPLED: `crypto::digest::Sha256::default`
- */
-crypto_digest_t *
-crypto_digest256_new(digest_algorithm_t algorithm)
-{
-  tor_assert(algorithm == DIGEST_SHA256 || algorithm == DIGEST_SHA3_256);
-  return crypto_digest_new_internal(algorithm);
-}
-
-/** Allocate and return a new digest object to compute 512-bit digests
- * using <b>algorithm</b>. */
-crypto_digest_t *
-crypto_digest512_new(digest_algorithm_t algorithm)
-{
-  tor_assert(algorithm == DIGEST_SHA512 || algorithm == DIGEST_SHA3_512);
-  return crypto_digest_new_internal(algorithm);
-}
-
-/** Deallocate a digest object.
- */
-void
-crypto_digest_free_(crypto_digest_t *digest)
-{
-  if (!digest)
-    return;
-#ifdef ENABLE_NSS
-  if (library_supports_digest(digest->algorithm)) {
-    PK11_DestroyContext(digest->d.ctx, PR_TRUE);
-  }
-#endif
-  size_t bytes = crypto_digest_alloc_bytes(digest->algorithm);
-  memwipe(digest, 0, bytes);
-  tor_free(digest);
-}
-
-/** Add <b>len</b> bytes from <b>data</b> to the digest object.
- *
- * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_add_bytess`
- * C_RUST_COUPLED: `crypto::digest::Sha256::process`
- */
-void
-crypto_digest_add_bytes(crypto_digest_t *digest, const char *data,
-                        size_t len)
-{
-  tor_assert(digest);
-  tor_assert(data);
-  /* Using the SHA*_*() calls directly means we don't support doing
-   * SHA in hardware. But so far the delay of getting the question
-   * to the hardware, and hearing the answer, is likely higher than
-   * just doing it ourselves. Hashes are fast.
-   */
-  switch (digest->algorithm) {
-#ifdef ENABLE_NSS
-    case DIGEST_SHA1: /* fall through */
-    case DIGEST_SHA256: /* fall through */
-    case DIGEST_SHA512:
-      tor_assert(len <= UINT_MAX);
-      SECStatus s = PK11_DigestOp(digest->d.ctx,
-                                  (const unsigned char *)data,
-                                  (unsigned int)len);
-      tor_assert(s == SECSuccess);
-      break;
-#else
-    case DIGEST_SHA1:
-      SHA1_Update(&digest->d.sha1, (void*)data, len);
-      break;
-    case DIGEST_SHA256:
-      SHA256_Update(&digest->d.sha2, (void*)data, len);
-      break;
-    case DIGEST_SHA512:
-      SHA512_Update(&digest->d.sha512, (void*)data, len);
-      break;
-#endif
-    case DIGEST_SHA3_256: /* FALLSTHROUGH */
-    case DIGEST_SHA3_512:
-      keccak_digest_update(&digest->d.sha3, (const uint8_t *)data, len);
-      break;
-    default:
-      /* LCOV_EXCL_START */
-      tor_fragile_assert();
-      break;
-      /* LCOV_EXCL_STOP */
-  }
-}
-
-/** Compute the hash of the data that has been passed to the digest
- * object; write the first out_len bytes of the result to <b>out</b>.
- * <b>out_len</b> must be \<= DIGEST512_LEN.
- *
- * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_get_digest`
- * C_RUST_COUPLED: `impl digest::FixedOutput for Sha256`
- */
-void
-crypto_digest_get_digest(crypto_digest_t *digest,
-                         char *out, size_t out_len)
-{
-  unsigned char r[DIGEST512_LEN];
-  tor_assert(digest);
-  tor_assert(out);
-  tor_assert(out_len <= crypto_digest_algorithm_get_length(digest->algorithm));
-
-  /* The SHA-3 code handles copying into a temporary ctx, and also can handle
-   * short output buffers by truncating appropriately. */
-  if (digest->algorithm == DIGEST_SHA3_256 ||
-      digest->algorithm == DIGEST_SHA3_512) {
-    keccak_digest_sum(&digest->d.sha3, (uint8_t *)out, out_len);
-    return;
-  }
-
-#ifdef ENABLE_NSS
-  /* Copy into a temporary buffer since DigestFinal (alters) the context */
-  unsigned char buf[1024];
-  unsigned int saved_len = 0;
-  unsigned rlen;
-  unsigned char *saved = PK11_SaveContextAlloc(digest->d.ctx,
-                                               buf, sizeof(buf),
-                                               &saved_len);
-  tor_assert(saved);
-  SECStatus s = PK11_DigestFinal(digest->d.ctx, r, &rlen, sizeof(r));
-  tor_assert(s == SECSuccess);
-  tor_assert(rlen >= out_len);
-  s = PK11_RestoreContext(digest->d.ctx, saved, saved_len);
-  tor_assert(s == SECSuccess);
-  if (saved != buf) {
-    PORT_ZFree(saved, saved_len);
-  }
-#else
-  const size_t alloc_bytes = crypto_digest_alloc_bytes(digest->algorithm);
-  crypto_digest_t tmpenv;
-  /* memcpy into a temporary ctx, since SHA*_Final clears the context */
-  memcpy(&tmpenv, digest, alloc_bytes);
-  switch (digest->algorithm) {
-    case DIGEST_SHA1:
-      SHA1_Final(r, &tmpenv.d.sha1);
-      break;
-    case DIGEST_SHA256:
-      SHA256_Final(r, &tmpenv.d.sha2);
-      break;
-    case DIGEST_SHA512:
-      SHA512_Final(r, &tmpenv.d.sha512);
-      break;
-//LCOV_EXCL_START
-    case DIGEST_SHA3_256: /* FALLSTHROUGH */
-    case DIGEST_SHA3_512:
-    default:
-      log_warn(LD_BUG, "Handling unexpected algorithm %d", digest->algorithm);
-      /* This is fatal, because it should never happen. */
-      tor_assert_unreached();
-      break;
-//LCOV_EXCL_STOP
-  }
-#endif
-  memcpy(out, r, out_len);
-  memwipe(r, 0, sizeof(r));
-}
-
-/** Allocate and return a new digest object with the same state as
- * <b>digest</b>
- *
- * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_dup`
- * C_RUST_COUPLED: `impl Clone for crypto::digest::Sha256`
- */
-crypto_digest_t *
-crypto_digest_dup(const crypto_digest_t *digest)
-{
-  tor_assert(digest);
-  const size_t alloc_bytes = crypto_digest_alloc_bytes(digest->algorithm);
-  crypto_digest_t *result = tor_memdup(digest, alloc_bytes);
-#ifdef ENABLE_NSS
-  if (library_supports_digest(digest->algorithm)) {
-    result->d.ctx = PK11_CloneContext(digest->d.ctx);
-  }
-#endif
-  return result;
-}
-
-/** Temporarily save the state of <b>digest</b> in <b>checkpoint</b>.
- * Asserts that <b>digest</b> is a SHA1 digest object.
- */
-void
-crypto_digest_checkpoint(crypto_digest_checkpoint_t *checkpoint,
-                         const crypto_digest_t *digest)
-{
-  const size_t bytes = crypto_digest_alloc_bytes(digest->algorithm);
-  tor_assert(bytes <= sizeof(checkpoint->mem));
-#ifdef ENABLE_NSS
-  if (library_supports_digest(digest->algorithm)) {
-    unsigned char *allocated;
-    allocated = PK11_SaveContextAlloc(digest->d.ctx,
-                                      (unsigned char *)checkpoint->mem,
-                                      sizeof(checkpoint->mem),
-                                      &checkpoint->bytes_used);
-    /* No allocation is allowed here. */
-    tor_assert(allocated == checkpoint->mem);
-    return;
-  }
-#endif
-  memcpy(checkpoint->mem, digest, bytes);
-}
-
-/** Restore the state of  <b>digest</b> from <b>checkpoint</b>.
- * Asserts that <b>digest</b> is a SHA1 digest object. Requires that the
- * state was previously stored with crypto_digest_checkpoint() */
-void
-crypto_digest_restore(crypto_digest_t *digest,
-                      const crypto_digest_checkpoint_t *checkpoint)
-{
-  const size_t bytes = crypto_digest_alloc_bytes(digest->algorithm);
-#ifdef ENABLE_NSS
-  if (library_supports_digest(digest->algorithm)) {
-    SECStatus s = PK11_RestoreContext(digest->d.ctx,
-                                      (unsigned char *)checkpoint->mem,
-                                      checkpoint->bytes_used);
-    tor_assert(s == SECSuccess);
-    return;
-  }
-#endif
-  memcpy(digest, checkpoint->mem, bytes);
-}
-
-/** Replace the state of the digest object <b>into</b> with the state
- * of the digest object <b>from</b>.  Requires that 'into' and 'from'
- * have the same digest type.
- */
-void
-crypto_digest_assign(crypto_digest_t *into,
-                     const crypto_digest_t *from)
-{
-  tor_assert(into);
-  tor_assert(from);
-  tor_assert(into->algorithm == from->algorithm);
-  const size_t alloc_bytes = crypto_digest_alloc_bytes(from->algorithm);
-#ifdef ENABLE_NSS
-  if (library_supports_digest(from->algorithm)) {
-    PK11_DestroyContext(into->d.ctx, PR_TRUE);
-    into->d.ctx = PK11_CloneContext(from->d.ctx);
-    return;
-  }
-#endif
-  memcpy(into,from,alloc_bytes);
-}
-
-/** Given a list of strings in <b>lst</b>, set the <b>len_out</b>-byte digest
- * at <b>digest_out</b> to the hash of the concatenation of those strings,
- * plus the optional string <b>append</b>, computed with the algorithm
- * <b>alg</b>.
- * <b>out_len</b> must be \<= DIGEST512_LEN. */
-void
-crypto_digest_smartlist(char *digest_out, size_t len_out,
-                        const smartlist_t *lst,
-                        const char *append,
-                        digest_algorithm_t alg)
-{
-  crypto_digest_smartlist_prefix(digest_out, len_out, NULL, lst, append, alg);
-}
-
-/** Given a list of strings in <b>lst</b>, set the <b>len_out</b>-byte digest
- * at <b>digest_out</b> to the hash of the concatenation of: the
- * optional string <b>prepend</b>, those strings,
- * and the optional string <b>append</b>, computed with the algorithm
- * <b>alg</b>.
- * <b>len_out</b> must be \<= DIGEST512_LEN. */
-void
-crypto_digest_smartlist_prefix(char *digest_out, size_t len_out,
-                        const char *prepend,
-                        const smartlist_t *lst,
-                        const char *append,
-                        digest_algorithm_t alg)
-{
-  crypto_digest_t *d = crypto_digest_new_internal(alg);
-  if (prepend)
-    crypto_digest_add_bytes(d, prepend, strlen(prepend));
-  SMARTLIST_FOREACH(lst, const char *, cp,
-                    crypto_digest_add_bytes(d, cp, strlen(cp)));
-  if (append)
-    crypto_digest_add_bytes(d, append, strlen(append));
-  crypto_digest_get_digest(d, digest_out, len_out);
-  crypto_digest_free(d);
-}
-
-/** Compute the HMAC-SHA-256 of the <b>msg_len</b> bytes in <b>msg</b>, using
- * the <b>key</b> of length <b>key_len</b>.  Store the DIGEST256_LEN-byte
- * result in <b>hmac_out</b>. Asserts on failure.
- */
-void
-crypto_hmac_sha256(char *hmac_out,
-                   const char *key, size_t key_len,
-                   const char *msg, size_t msg_len)
-{
-  /* If we've got OpenSSL >=0.9.8 we can use its hmac implementation. */
-  tor_assert(key_len < INT_MAX);
-  tor_assert(msg_len < INT_MAX);
-  tor_assert(hmac_out);
-#ifdef ENABLE_NSS
-  PK11SlotInfo *slot = NULL;
-  PK11SymKey *symKey = NULL;
-  PK11Context *hmac = NULL;
-
-  int ok = 0;
-  SECStatus s;
-  SECItem keyItem, paramItem;
-  keyItem.data = (unsigned char *)key;
-  keyItem.len = (unsigned)key_len;
-  paramItem.type = siBuffer;
-  paramItem.data = NULL;
-  paramItem.len = 0;
-
-  slot = PK11_GetBestSlot(CKM_SHA256_HMAC, NULL);
-  if (!slot)
-    goto done;
-  symKey = PK11_ImportSymKey(slot, CKM_SHA256_HMAC,
-                             PK11_OriginUnwrap, CKA_SIGN, &keyItem, NULL);
-  if (!symKey)
-    goto done;
-
-  hmac = PK11_CreateContextBySymKey(CKM_SHA256_HMAC, CKA_SIGN, symKey,
-                                    ¶mItem);
-  if (!hmac)
-    goto done;
-  s = PK11_DigestBegin(hmac);
-  if (s != SECSuccess)
-    goto done;
-  s = PK11_DigestOp(hmac, (const unsigned char *)msg, (unsigned int)msg_len);
-  if (s != SECSuccess)
-    goto done;
-  unsigned int len=0;
-  s = PK11_DigestFinal(hmac, (unsigned char *)hmac_out, &len, DIGEST256_LEN);
-  if (s != SECSuccess || len != DIGEST256_LEN)
-    goto done;
-  ok = 1;
-
- done:
-  if (hmac)
-    PK11_DestroyContext(hmac, PR_TRUE);
-  if (symKey)
-    PK11_FreeSymKey(symKey);
-  if (slot)
-    PK11_FreeSlot(slot);
-
-  tor_assert(ok);
-#else
-  unsigned char *rv = NULL;
-  rv = HMAC(EVP_sha256(), key, (int)key_len, (unsigned char*)msg, (int)msg_len,
-            (unsigned char*)hmac_out, NULL);
-  tor_assert(rv);
-#endif
-}
-
 /** Compute a MAC using SHA3-256 of <b>msg_len</b> bytes in <b>msg</b> using a
  * <b>key</b> of length <b>key_len</b> and a <b>salt</b> of length
  * <b>salt_len</b>. Store the result of <b>len_out</b> bytes in in
@@ -779,7 +135,23 @@ crypto_mac_sha3_256(uint8_t *mac_out, size_t len_out,
 
 /** Internal state for a eXtendable-Output Function (XOF). */
 struct crypto_xof_t {
+#ifdef OPENSSL_HAS_SHAKE3_EVP
+  /* XXXX We can't enable this yet, because OpenSSL's
+   * DigestFinalXOF function can't be called repeatedly on the same
+   * XOF.
+   *
+   * We could in theory use the undocumented SHA3_absorb and SHA3_squeeze
+   * functions, but let's not mess with undocumented OpenSSL internals any
+   * more than we have to.
+   *
+   * We could also revise our XOF code so that it only allows a single
+   * squeeze operation; we don't require streaming squeeze operations
+   * outside the tests yet.
+   */
+  EVP_MD_CTX *ctx;
+#else /* !(defined(OPENSSL_HAS_SHAKE3_EVP)) */
   keccak_state s;
+#endif /* defined(OPENSSL_HAS_SHAKE3_EVP) */
 };
 
 /** Allocate a new XOF object backed by SHAKE-256.  The security level
@@ -792,7 +164,14 @@ crypto_xof_new(void)
 {
   crypto_xof_t *xof;
   xof = tor_malloc(sizeof(crypto_xof_t));
+#ifdef OPENSSL_HAS_SHAKE256
+  xof->ctx = EVP_MD_CTX_new();
+  tor_assert(xof->ctx);
+  int r = EVP_DigestInit(xof->ctx, EVP_shake256());
+  tor_assert(r == 1);
+#else /* !(defined(OPENSSL_HAS_SHAKE256)) */
   keccak_xof_init(&xof->s, 256);
+#endif /* defined(OPENSSL_HAS_SHAKE256) */
   return xof;
 }
 
@@ -803,8 +182,13 @@ crypto_xof_new(void)
 void
 crypto_xof_add_bytes(crypto_xof_t *xof, const uint8_t *data, size_t len)
 {
+#ifdef OPENSSL_HAS_SHAKE256
+  int r = EVP_DigestUpdate(xof->ctx, data, len);
+  tor_assert(r == 1);
+#else
   int i = keccak_xof_absorb(&xof->s, data, len);
   tor_assert(i == 0);
+#endif /* defined(OPENSSL_HAS_SHAKE256) */
 }
 
 /** Squeeze bytes out of a XOF object.  Calling this routine will render
@@ -813,8 +197,13 @@ crypto_xof_add_bytes(crypto_xof_t *xof, const uint8_t *data, size_t len)
 void
 crypto_xof_squeeze_bytes(crypto_xof_t *xof, uint8_t *out, size_t len)
 {
+#ifdef OPENSSL_HAS_SHAKE256
+  int r = EVP_DigestFinalXOF(xof->ctx, out, len);
+  tor_assert(r == 1);
+#else
   int i = keccak_xof_squeeze(&xof->s, out, len);
   tor_assert(i == 0);
+#endif /* defined(OPENSSL_HAS_SHAKE256) */
 }
 
 /** Cleanse and deallocate a XOF object. */
@@ -823,6 +212,34 @@ crypto_xof_free_(crypto_xof_t *xof)
 {
   if (!xof)
     return;
+#ifdef OPENSSL_HAS_SHAKE256
+  if (xof->ctx)
+    EVP_MD_CTX_free(xof->ctx);
+#endif
   memwipe(xof, 0, sizeof(crypto_xof_t));
   tor_free(xof);
 }
+
+/** Compute the XOF (SHAKE256) of a <b>input_len</b> bytes at <b>input</b>,
+ * putting <b>output_len</b> bytes at <b>output</b>. */
+void
+crypto_xof(uint8_t *output, size_t output_len,
+           const uint8_t *input, size_t input_len)
+{
+#ifdef OPENSSL_HAS_SHA3
+  EVP_MD_CTX *ctx = EVP_MD_CTX_new();
+  tor_assert(ctx);
+  int r = EVP_DigestInit(ctx, EVP_shake256());
+  tor_assert(r == 1);
+  r = EVP_DigestUpdate(ctx, input, input_len);
+  tor_assert(r == 1);
+  r = EVP_DigestFinalXOF(ctx, output, output_len);
+  tor_assert(r == 1);
+  EVP_MD_CTX_free(ctx);
+#else /* !(defined(OPENSSL_HAS_SHA3)) */
+  crypto_xof_t *xof = crypto_xof_new();
+  crypto_xof_add_bytes(xof, input, input_len);
+  crypto_xof_squeeze_bytes(xof, output, output_len);
+  crypto_xof_free(xof);
+#endif /* defined(OPENSSL_HAS_SHA3) */
+}
diff --git a/src/lib/crypt_ops/crypto_digest.h b/src/lib/crypt_ops/crypto_digest.h
index 47e60ce61..5869db780 100644
--- a/src/lib/crypt_ops/crypto_digest.h
+++ b/src/lib/crypt_ops/crypto_digest.h
@@ -124,6 +124,8 @@ void crypto_xof_squeeze_bytes(crypto_xof_t *xof, uint8_t *out, size_t len);
 void crypto_xof_free_(crypto_xof_t *xof);
 #define crypto_xof_free(xof) \
   FREE_AND_NULL(crypto_xof_t, crypto_xof_free_, (xof))
+void crypto_xof(uint8_t *output, size_t output_len,
+                const uint8_t *input, size_t input_len);
 
 #ifdef TOR_UNIT_TESTS
 digest_algorithm_t crypto_digest_get_algorithm(crypto_digest_t *digest);
diff --git a/src/lib/crypt_ops/crypto_digest_nss.c b/src/lib/crypt_ops/crypto_digest_nss.c
new file mode 100644
index 000000000..b73f0736f
--- /dev/null
+++ b/src/lib/crypt_ops/crypto_digest_nss.c
@@ -0,0 +1,560 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file crypto_digest_nss.c
+ * \brief Block of functions related with digest and xof utilities and
+ * operations (NSS specific implementations).
+ **/
+
+#include "lib/container/smartlist.h"
+#include "lib/crypt_ops/crypto_digest.h"
+#include "lib/crypt_ops/crypto_util.h"
+#include "lib/log/log.h"
+#include "lib/log/util_bug.h"
+
+#include "keccak-tiny/keccak-tiny.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "lib/arch/bytes.h"
+
+DISABLE_GCC_WARNING(strict-prototypes)
+#include <pk11pub.h>
+ENABLE_GCC_WARNING(strict-prototypes)
+
+/**
+ * Convert a digest_algorithm_t (used by tor) to a HashType (used by NSS).
+ * On failure, return SEC_OID_UNKNOWN. */
+static SECOidTag
+digest_alg_to_nss_oid(digest_algorithm_t alg)
+{
+  switch (alg) {
+    case DIGEST_SHA1: return SEC_OID_SHA1;
+    case DIGEST_SHA256: return SEC_OID_SHA256;
+    case DIGEST_SHA512: return SEC_OID_SHA512;
+    case DIGEST_SHA3_256: /* Fall through */
+    case DIGEST_SHA3_512: /* Fall through */
+    default:
+      return SEC_OID_UNKNOWN;
+  }
+}
+
+/* Helper: get an unkeyed digest via pk11wrap */
+static int
+digest_nss_internal(SECOidTag alg,
+                    char *digest, unsigned len_out,
+                    const char *msg, size_t msg_len)
+{
+  if (alg == SEC_OID_UNKNOWN)
+    return -1;
+  tor_assert(msg_len <= UINT_MAX);
+
+  int rv = -1;
+  SECStatus s;
+  PK11Context *ctx = PK11_CreateDigestContext(alg);
+  if (!ctx)
+    return -1;
+
+  s = PK11_DigestBegin(ctx);
+  if (s != SECSuccess)
+    goto done;
+
+  s = PK11_DigestOp(ctx, (const unsigned char *)msg, (unsigned int)msg_len);
+  if (s != SECSuccess)
+    goto done;
+
+  unsigned int len = 0;
+  s = PK11_DigestFinal(ctx, (unsigned char *)digest, &len, len_out);
+  if (s != SECSuccess)
+    goto done;
+
+  rv = 0;
+ done:
+  PK11_DestroyContext(ctx, PR_TRUE);
+  return rv;
+}
+
+/** True iff alg is implemented in our crypto library, and we want to use that
+ * implementation */
+static bool
+library_supports_digest(digest_algorithm_t alg)
+{
+  switch (alg) {
+    case DIGEST_SHA1: /* Fall through */
+    case DIGEST_SHA256: /* Fall through */
+    case DIGEST_SHA512: /* Fall through */
+      return true;
+    case DIGEST_SHA3_256: /* Fall through */
+    case DIGEST_SHA3_512: /* Fall through */
+    default:
+      return false;
+  }
+}
+
+/* Crypto digest functions */
+
+/** Compute the SHA1 digest of the <b>len</b> bytes on data stored in
+ * <b>m</b>.  Write the DIGEST_LEN byte result into <b>digest</b>.
+ * Return 0 on success, -1 on failure.
+ */
+MOCK_IMPL(int,
+crypto_digest,(char *digest, const char *m, size_t len))
+{
+  tor_assert(m);
+  tor_assert(digest);
+  return digest_nss_internal(SEC_OID_SHA1, digest, DIGEST_LEN, m, len);
+}
+
+/** Compute a 256-bit digest of <b>len</b> bytes in data stored in <b>m</b>,
+ * using the algorithm <b>algorithm</b>.  Write the DIGEST_LEN256-byte result
+ * into <b>digest</b>.  Return 0 on success, -1 on failure. */
+int
+crypto_digest256(char *digest, const char *m, size_t len,
+                 digest_algorithm_t algorithm)
+{
+  tor_assert(m);
+  tor_assert(digest);
+  tor_assert(algorithm == DIGEST_SHA256 || algorithm == DIGEST_SHA3_256);
+
+  int ret = 0;
+  if (algorithm == DIGEST_SHA256) {
+    return digest_nss_internal(SEC_OID_SHA256, digest, DIGEST256_LEN, m, len);
+  } else {
+    ret = (sha3_256((uint8_t *)digest, DIGEST256_LEN,(const uint8_t *)m, len)
+           > -1);
+  }
+
+  if (!ret)
+    return -1;
+  return 0;
+}
+
+/** Compute a 512-bit digest of <b>len</b> bytes in data stored in <b>m</b>,
+ * using the algorithm <b>algorithm</b>.  Write the DIGEST_LEN512-byte result
+ * into <b>digest</b>.  Return 0 on success, -1 on failure. */
+int
+crypto_digest512(char *digest, const char *m, size_t len,
+                 digest_algorithm_t algorithm)
+{
+  tor_assert(m);
+  tor_assert(digest);
+  tor_assert(algorithm == DIGEST_SHA512 || algorithm == DIGEST_SHA3_512);
+
+  int ret = 0;
+  if (algorithm == DIGEST_SHA512) {
+    return digest_nss_internal(SEC_OID_SHA512, digest, DIGEST512_LEN, m, len);
+  } else {
+    ret = (sha3_512((uint8_t*)digest, DIGEST512_LEN, (const uint8_t*)m, len)
+           > -1);
+  }
+
+  if (!ret)
+    return -1;
+  return 0;
+}
+
+/** Intermediate information about the digest of a stream of data. */
+struct crypto_digest_t {
+  digest_algorithm_t algorithm; /**< Which algorithm is in use? */
+   /** State for the digest we're using.  Only one member of the
+    * union is usable, depending on the value of <b>algorithm</b>. Note also
+    * that space for other members might not even be allocated!
+    */
+  union {
+    PK11Context *ctx;
+    keccak_state sha3; /**< state for SHA3-[256,512] */
+  } d;
+};
+
+#ifdef TOR_UNIT_TESTS
+
+digest_algorithm_t
+crypto_digest_get_algorithm(crypto_digest_t *digest)
+{
+  tor_assert(digest);
+
+  return digest->algorithm;
+}
+
+#endif /* defined(TOR_UNIT_TESTS) */
+
+/**
+ * Return the number of bytes we need to malloc in order to get a
+ * crypto_digest_t for <b>alg</b>, or the number of bytes we need to wipe
+ * when we free one.
+ */
+static size_t
+crypto_digest_alloc_bytes(digest_algorithm_t alg)
+{
+  /* Helper: returns the number of bytes in the 'f' field of 'st' */
+#define STRUCT_FIELD_SIZE(st, f) (sizeof( ((st*)0)->f ))
+  /* Gives the length of crypto_digest_t through the end of the field 'd' */
+#define END_OF_FIELD(f) (offsetof(crypto_digest_t, f) + \
+                         STRUCT_FIELD_SIZE(crypto_digest_t, f))
+  switch (alg) {
+    case DIGEST_SHA1: /* Fall through */
+    case DIGEST_SHA256: /* Fall through */
+    case DIGEST_SHA512:
+      return END_OF_FIELD(d.ctx);
+    case DIGEST_SHA3_256:
+    case DIGEST_SHA3_512:
+      return END_OF_FIELD(d.sha3);
+    default:
+      tor_assert(0); // LCOV_EXCL_LINE
+      return 0;      // LCOV_EXCL_LINE
+  }
+#undef END_OF_FIELD
+#undef STRUCT_FIELD_SIZE
+}
+
+/**
+ * Internal function: create and return a new digest object for 'algorithm'.
+ * Does not typecheck the algorithm.
+ */
+static crypto_digest_t *
+crypto_digest_new_internal(digest_algorithm_t algorithm)
+{
+  crypto_digest_t *r = tor_malloc(crypto_digest_alloc_bytes(algorithm));
+  r->algorithm = algorithm;
+
+  switch (algorithm)
+    {
+    case DIGEST_SHA1: /* fall through */
+    case DIGEST_SHA256: /* fall through */
+    case DIGEST_SHA512:
+      r->d.ctx = PK11_CreateDigestContext(digest_alg_to_nss_oid(algorithm));
+      if (BUG(!r->d.ctx)) {
+        tor_free(r);
+        return NULL;
+      }
+      if (BUG(SECSuccess != PK11_DigestBegin(r->d.ctx))) {
+        crypto_digest_free(r);
+        return NULL;
+      }
+      break;
+    case DIGEST_SHA3_256:
+      keccak_digest_init(&r->d.sha3, 256);
+      break;
+    case DIGEST_SHA3_512:
+      keccak_digest_init(&r->d.sha3, 512);
+      break;
+    default:
+      tor_assert_unreached();
+    }
+
+  return r;
+}
+
+/** Allocate and return a new digest object to compute SHA1 digests.
+ */
+crypto_digest_t *
+crypto_digest_new(void)
+{
+  return crypto_digest_new_internal(DIGEST_SHA1);
+}
+
+/** Allocate and return a new digest object to compute 256-bit digests
+ * using <b>algorithm</b>.
+ *
+ * C_RUST_COUPLED: `external::crypto_digest::crypto_digest256_new`
+ * C_RUST_COUPLED: `crypto::digest::Sha256::default`
+ */
+crypto_digest_t *
+crypto_digest256_new(digest_algorithm_t algorithm)
+{
+  tor_assert(algorithm == DIGEST_SHA256 || algorithm == DIGEST_SHA3_256);
+  return crypto_digest_new_internal(algorithm);
+}
+
+/** Allocate and return a new digest object to compute 512-bit digests
+ * using <b>algorithm</b>. */
+crypto_digest_t *
+crypto_digest512_new(digest_algorithm_t algorithm)
+{
+  tor_assert(algorithm == DIGEST_SHA512 || algorithm == DIGEST_SHA3_512);
+  return crypto_digest_new_internal(algorithm);
+}
+
+/** Deallocate a digest object.
+ */
+void
+crypto_digest_free_(crypto_digest_t *digest)
+{
+  if (!digest)
+    return;
+  if (library_supports_digest(digest->algorithm)) {
+    PK11_DestroyContext(digest->d.ctx, PR_TRUE);
+  }
+  size_t bytes = crypto_digest_alloc_bytes(digest->algorithm);
+  memwipe(digest, 0, bytes);
+  tor_free(digest);
+}
+
+/** Add <b>len</b> bytes from <b>data</b> to the digest object.
+ *
+ * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_add_bytess`
+ * C_RUST_COUPLED: `crypto::digest::Sha256::process`
+ */
+void
+crypto_digest_add_bytes(crypto_digest_t *digest, const char *data,
+                        size_t len)
+{
+  tor_assert(digest);
+  tor_assert(data);
+  /* Using the SHA*_*() calls directly means we don't support doing
+   * SHA in hardware. But so far the delay of getting the question
+   * to the hardware, and hearing the answer, is likely higher than
+   * just doing it ourselves. Hashes are fast.
+   */
+  switch (digest->algorithm) {
+    case DIGEST_SHA1: /* fall through */
+    case DIGEST_SHA256: /* fall through */
+    case DIGEST_SHA512:
+      tor_assert(len <= UINT_MAX);
+      SECStatus s = PK11_DigestOp(digest->d.ctx,
+                                  (const unsigned char *)data,
+                                  (unsigned int)len);
+      tor_assert(s == SECSuccess);
+      break;
+    case DIGEST_SHA3_256: /* FALLSTHROUGH */
+    case DIGEST_SHA3_512:
+      keccak_digest_update(&digest->d.sha3, (const uint8_t *)data, len);
+      break;
+    default:
+      /* LCOV_EXCL_START */
+      tor_fragile_assert();
+      break;
+      /* LCOV_EXCL_STOP */
+  }
+}
+
+/** Compute the hash of the data that has been passed to the digest
+ * object; write the first out_len bytes of the result to <b>out</b>.
+ * <b>out_len</b> must be \<= DIGEST512_LEN.
+ *
+ * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_get_digest`
+ * C_RUST_COUPLED: `impl digest::FixedOutput for Sha256`
+ */
+void
+crypto_digest_get_digest(crypto_digest_t *digest,
+                         char *out, size_t out_len)
+{
+  unsigned char r[DIGEST512_LEN];
+  tor_assert(digest);
+  tor_assert(out);
+  tor_assert(out_len <= crypto_digest_algorithm_get_length(digest->algorithm));
+
+  /* The SHA-3 code handles copying into a temporary ctx, and also can handle
+   * short output buffers by truncating appropriately. */
+  if (digest->algorithm == DIGEST_SHA3_256 ||
+      digest->algorithm == DIGEST_SHA3_512) {
+    keccak_digest_sum(&digest->d.sha3, (uint8_t *)out, out_len);
+    return;
+  }
+
+  /* Copy into a temporary buffer since DigestFinal (alters) the context */
+  unsigned char buf[1024];
+  unsigned int saved_len = 0;
+  unsigned rlen;
+  unsigned char *saved = PK11_SaveContextAlloc(digest->d.ctx,
+                                               buf, sizeof(buf),
+                                               &saved_len);
+  tor_assert(saved);
+  SECStatus s = PK11_DigestFinal(digest->d.ctx, r, &rlen, sizeof(r));
+  tor_assert(s == SECSuccess);
+  tor_assert(rlen >= out_len);
+  s = PK11_RestoreContext(digest->d.ctx, saved, saved_len);
+  tor_assert(s == SECSuccess);
+
+  if (saved != buf) {
+    PORT_ZFree(saved, saved_len);
+  }
+  memcpy(out, r, out_len);
+  memwipe(r, 0, sizeof(r));
+}
+
+/** Allocate and return a new digest object with the same state as
+ * <b>digest</b>
+ *
+ * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_dup`
+ * C_RUST_COUPLED: `impl Clone for crypto::digest::Sha256`
+ */
+crypto_digest_t *
+crypto_digest_dup(const crypto_digest_t *digest)
+{
+  tor_assert(digest);
+  const size_t alloc_bytes = crypto_digest_alloc_bytes(digest->algorithm);
+  crypto_digest_t *result = tor_memdup(digest, alloc_bytes);
+
+  if (library_supports_digest(digest->algorithm)) {
+    result->d.ctx = PK11_CloneContext(digest->d.ctx);
+  }
+
+  return result;
+}
+
+/** Temporarily save the state of <b>digest</b> in <b>checkpoint</b>.
+ * Asserts that <b>digest</b> is a SHA1 digest object.
+ */
+void
+crypto_digest_checkpoint(crypto_digest_checkpoint_t *checkpoint,
+                         const crypto_digest_t *digest)
+{
+  const size_t bytes = crypto_digest_alloc_bytes(digest->algorithm);
+  tor_assert(bytes <= sizeof(checkpoint->mem));
+  if (library_supports_digest(digest->algorithm)) {
+    unsigned char *allocated;
+    allocated = PK11_SaveContextAlloc(digest->d.ctx,
+                                      (unsigned char *)checkpoint->mem,
+                                      sizeof(checkpoint->mem),
+                                      &checkpoint->bytes_used);
+    /* No allocation is allowed here. */
+    tor_assert(allocated == checkpoint->mem);
+    return;
+  }
+  memcpy(checkpoint->mem, digest, bytes);
+}
+
+/** Restore the state of  <b>digest</b> from <b>checkpoint</b>.
+ * Asserts that <b>digest</b> is a SHA1 digest object. Requires that the
+ * state was previously stored with crypto_digest_checkpoint() */
+void
+crypto_digest_restore(crypto_digest_t *digest,
+                      const crypto_digest_checkpoint_t *checkpoint)
+{
+  const size_t bytes = crypto_digest_alloc_bytes(digest->algorithm);
+  if (library_supports_digest(digest->algorithm)) {
+    SECStatus s = PK11_RestoreContext(digest->d.ctx,
+                                      (unsigned char *)checkpoint->mem,
+                                      checkpoint->bytes_used);
+    tor_assert(s == SECSuccess);
+    return;
+  }
+  memcpy(digest, checkpoint->mem, bytes);
+}
+
+/** Replace the state of the digest object <b>into</b> with the state
+ * of the digest object <b>from</b>.  Requires that 'into' and 'from'
+ * have the same digest type.
+ */
+void
+crypto_digest_assign(crypto_digest_t *into,
+                     const crypto_digest_t *from)
+{
+  tor_assert(into);
+  tor_assert(from);
+  tor_assert(into->algorithm == from->algorithm);
+  const size_t alloc_bytes = crypto_digest_alloc_bytes(from->algorithm);
+  if (library_supports_digest(from->algorithm)) {
+    PK11_DestroyContext(into->d.ctx, PR_TRUE);
+    into->d.ctx = PK11_CloneContext(from->d.ctx);
+    return;
+  }
+  memcpy(into,from,alloc_bytes);
+}
+
+/** Given a list of strings in <b>lst</b>, set the <b>len_out</b>-byte digest
+ * at <b>digest_out</b> to the hash of the concatenation of those strings,
+ * plus the optional string <b>append</b>, computed with the algorithm
+ * <b>alg</b>.
+ * <b>out_len</b> must be \<= DIGEST512_LEN. */
+void
+crypto_digest_smartlist(char *digest_out, size_t len_out,
+                        const smartlist_t *lst,
+                        const char *append,
+                        digest_algorithm_t alg)
+{
+  crypto_digest_smartlist_prefix(digest_out, len_out, NULL, lst, append, alg);
+}
+
+/** Given a list of strings in <b>lst</b>, set the <b>len_out</b>-byte digest
+ * at <b>digest_out</b> to the hash of the concatenation of: the
+ * optional string <b>prepend</b>, those strings,
+ * and the optional string <b>append</b>, computed with the algorithm
+ * <b>alg</b>.
+ * <b>len_out</b> must be \<= DIGEST512_LEN. */
+void
+crypto_digest_smartlist_prefix(char *digest_out, size_t len_out,
+                        const char *prepend,
+                        const smartlist_t *lst,
+                        const char *append,
+                        digest_algorithm_t alg)
+{
+  crypto_digest_t *d = crypto_digest_new_internal(alg);
+  if (prepend)
+    crypto_digest_add_bytes(d, prepend, strlen(prepend));
+  SMARTLIST_FOREACH(lst, const char *, cp,
+                    crypto_digest_add_bytes(d, cp, strlen(cp)));
+  if (append)
+    crypto_digest_add_bytes(d, append, strlen(append));
+  crypto_digest_get_digest(d, digest_out, len_out);
+  crypto_digest_free(d);
+}
+
+/** Compute the HMAC-SHA-256 of the <b>msg_len</b> bytes in <b>msg</b>, using
+ * the <b>key</b> of length <b>key_len</b>.  Store the DIGEST256_LEN-byte
+ * result in <b>hmac_out</b>. Asserts on failure.
+ */
+void
+crypto_hmac_sha256(char *hmac_out,
+                   const char *key, size_t key_len,
+                   const char *msg, size_t msg_len)
+{
+  /* If we've got OpenSSL >=0.9.8 we can use its hmac implementation. */
+  tor_assert(key_len < INT_MAX);
+  tor_assert(msg_len < INT_MAX);
+  tor_assert(hmac_out);
+
+  PK11SlotInfo *slot = NULL;
+  PK11SymKey *symKey = NULL;
+  PK11Context *hmac = NULL;
+
+  int ok = 0;
+  SECStatus s;
+  SECItem keyItem, paramItem;
+  keyItem.data = (unsigned char *)key;
+  keyItem.len = (unsigned)key_len;
+  paramItem.type = siBuffer;
+  paramItem.data = NULL;
+  paramItem.len = 0;
+
+  slot = PK11_GetBestSlot(CKM_SHA256_HMAC, NULL);
+  if (!slot)
+    goto done;
+  symKey = PK11_ImportSymKey(slot, CKM_SHA256_HMAC,
+                             PK11_OriginUnwrap, CKA_SIGN, &keyItem, NULL);
+  if (!symKey)
+    goto done;
+
+  hmac = PK11_CreateContextBySymKey(CKM_SHA256_HMAC, CKA_SIGN, symKey,
+                                    ¶mItem);
+  if (!hmac)
+    goto done;
+  s = PK11_DigestBegin(hmac);
+  if (s != SECSuccess)
+    goto done;
+  s = PK11_DigestOp(hmac, (const unsigned char *)msg, (unsigned int)msg_len);
+  if (s != SECSuccess)
+    goto done;
+  unsigned int len=0;
+  s = PK11_DigestFinal(hmac, (unsigned char *)hmac_out, &len, DIGEST256_LEN);
+  if (s != SECSuccess || len != DIGEST256_LEN)
+    goto done;
+  ok = 1;
+
+ done:
+  if (hmac)
+    PK11_DestroyContext(hmac, PR_TRUE);
+  if (symKey)
+    PK11_FreeSymKey(symKey);
+  if (slot)
+    PK11_FreeSlot(slot);
+
+  tor_assert(ok);
+}
+
diff --git a/src/lib/crypt_ops/crypto_digest_openssl.c b/src/lib/crypt_ops/crypto_digest_openssl.c
new file mode 100644
index 000000000..c631b0eac
--- /dev/null
+++ b/src/lib/crypt_ops/crypto_digest_openssl.c
@@ -0,0 +1,522 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file crypto_digest_openssl.c
+ * \brief Block of functions related with digest and xof utilities and
+ * operations (OpenSSL specific implementations).
+ **/
+
+#include "lib/container/smartlist.h"
+#include "lib/crypt_ops/crypto_digest.h"
+#include "lib/crypt_ops/crypto_util.h"
+#include "lib/log/log.h"
+#include "lib/log/util_bug.h"
+
+#include "keccak-tiny/keccak-tiny.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "lib/arch/bytes.h"
+
+#include "lib/crypt_ops/crypto_openssl_mgt.h"
+
+DISABLE_GCC_WARNING(redundant-decls)
+
+#include <openssl/hmac.h>
+#include <openssl/sha.h>
+
+ENABLE_GCC_WARNING(redundant-decls)
+
+/* Crypto digest functions */
+
+/** Compute the SHA1 digest of the <b>len</b> bytes on data stored in
+ * <b>m</b>.  Write the DIGEST_LEN byte result into <b>digest</b>.
+ * Return 0 on success, -1 on failure.
+ */
+MOCK_IMPL(int,
+crypto_digest,(char *digest, const char *m, size_t len))
+{
+  tor_assert(m);
+  tor_assert(digest);
+  if (SHA1((const unsigned char*)m,len,(unsigned char*)digest) == NULL) {
+    return -1;
+  }
+  return 0;
+}
+
+/** Compute a 256-bit digest of <b>len</b> bytes in data stored in <b>m</b>,
+ * using the algorithm <b>algorithm</b>.  Write the DIGEST_LEN256-byte result
+ * into <b>digest</b>.  Return 0 on success, -1 on failure. */
+int
+crypto_digest256(char *digest, const char *m, size_t len,
+                 digest_algorithm_t algorithm)
+{
+  tor_assert(m);
+  tor_assert(digest);
+  tor_assert(algorithm == DIGEST_SHA256 || algorithm == DIGEST_SHA3_256);
+
+  int ret = 0;
+  if (algorithm == DIGEST_SHA256) {
+    ret = (SHA256((const uint8_t*)m,len,(uint8_t*)digest) != NULL);
+  } else {
+#ifdef OPENSSL_HAS_SHA3
+    unsigned int dlen = DIGEST256_LEN;
+    ret = EVP_Digest(m, len, (uint8_t*)digest, &dlen, EVP_sha3_256(), NULL);
+#else
+    ret = (sha3_256((uint8_t *)digest, DIGEST256_LEN,(const uint8_t *)m, len)
+           > -1);
+#endif /* defined(OPENSSL_HAS_SHA3) */
+  }
+
+  if (!ret)
+    return -1;
+  return 0;
+}
+
+/** Compute a 512-bit digest of <b>len</b> bytes in data stored in <b>m</b>,
+ * using the algorithm <b>algorithm</b>.  Write the DIGEST_LEN512-byte result
+ * into <b>digest</b>.  Return 0 on success, -1 on failure. */
+int
+crypto_digest512(char *digest, const char *m, size_t len,
+                 digest_algorithm_t algorithm)
+{
+  tor_assert(m);
+  tor_assert(digest);
+  tor_assert(algorithm == DIGEST_SHA512 || algorithm == DIGEST_SHA3_512);
+
+  int ret = 0;
+  if (algorithm == DIGEST_SHA512) {
+    ret = (SHA512((const unsigned char*)m,len,(unsigned char*)digest)
+           != NULL);
+  } else {
+#ifdef OPENSSL_HAS_SHA3
+    unsigned int dlen = DIGEST512_LEN;
+    ret = EVP_Digest(m, len, (uint8_t*)digest, &dlen, EVP_sha3_512(), NULL);
+#else
+    ret = (sha3_512((uint8_t*)digest, DIGEST512_LEN, (const uint8_t*)m, len)
+           > -1);
+#endif /* defined(OPENSSL_HAS_SHA3) */
+  }
+
+  if (!ret)
+    return -1;
+  return 0;
+}
+
+/** Intermediate information about the digest of a stream of data. */
+struct crypto_digest_t {
+  digest_algorithm_t algorithm; /**< Which algorithm is in use? */
+   /** State for the digest we're using.  Only one member of the
+    * union is usable, depending on the value of <b>algorithm</b>. Note also
+    * that space for other members might not even be allocated!
+    */
+  union {
+    SHA_CTX sha1; /**< state for SHA1 */
+    SHA256_CTX sha2; /**< state for SHA256 */
+    SHA512_CTX sha512; /**< state for SHA512 */
+#ifdef OPENSSL_HAS_SHA3
+    EVP_MD_CTX *md;
+#else
+    keccak_state sha3; /**< state for SHA3-[256,512] */
+#endif
+  } d;
+};
+
+#ifdef TOR_UNIT_TESTS
+
+digest_algorithm_t
+crypto_digest_get_algorithm(crypto_digest_t *digest)
+{
+  tor_assert(digest);
+
+  return digest->algorithm;
+}
+
+#endif /* defined(TOR_UNIT_TESTS) */
+
+/**
+ * Return the number of bytes we need to malloc in order to get a
+ * crypto_digest_t for <b>alg</b>, or the number of bytes we need to wipe
+ * when we free one.
+ */
+static size_t
+crypto_digest_alloc_bytes(digest_algorithm_t alg)
+{
+  /* Helper: returns the number of bytes in the 'f' field of 'st' */
+#define STRUCT_FIELD_SIZE(st, f) (sizeof( ((st*)0)->f ))
+  /* Gives the length of crypto_digest_t through the end of the field 'd' */
+#define END_OF_FIELD(f) (offsetof(crypto_digest_t, f) + \
+                         STRUCT_FIELD_SIZE(crypto_digest_t, f))
+  switch (alg) {
+    case DIGEST_SHA1:
+      return END_OF_FIELD(d.sha1);
+    case DIGEST_SHA256:
+      return END_OF_FIELD(d.sha2);
+    case DIGEST_SHA512:
+      return END_OF_FIELD(d.sha512);
+#ifdef OPENSSL_HAS_SHA3
+    case DIGEST_SHA3_256: /* Fall through */
+    case DIGEST_SHA3_512:
+      return END_OF_FIELD(d.md);
+#else
+    case DIGEST_SHA3_256: /* Fall through */
+    case DIGEST_SHA3_512:
+      return END_OF_FIELD(d.sha3);
+#endif /* defined(OPENSSL_HAS_SHA3) */
+    default:
+      tor_assert(0); // LCOV_EXCL_LINE
+      return 0;      // LCOV_EXCL_LINE
+  }
+#undef END_OF_FIELD
+#undef STRUCT_FIELD_SIZE
+}
+
+/**
+ * Internal function: create and return a new digest object for 'algorithm'.
+ * Does not typecheck the algorithm.
+ */
+static crypto_digest_t *
+crypto_digest_new_internal(digest_algorithm_t algorithm)
+{
+  crypto_digest_t *r = tor_malloc(crypto_digest_alloc_bytes(algorithm));
+  r->algorithm = algorithm;
+
+  switch (algorithm)
+    {
+    case DIGEST_SHA1:
+      SHA1_Init(&r->d.sha1);
+      break;
+    case DIGEST_SHA256:
+      SHA256_Init(&r->d.sha2);
+      break;
+    case DIGEST_SHA512:
+      SHA512_Init(&r->d.sha512);
+      break;
+#ifdef OPENSSL_HAS_SHA3
+    case DIGEST_SHA3_256:
+      r->d.md = EVP_MD_CTX_new();
+      if (!EVP_DigestInit(r->d.md, EVP_sha3_256())) {
+        crypto_digest_free(r);
+        return NULL;
+      }
+      break;
+    case DIGEST_SHA3_512:
+      r->d.md = EVP_MD_CTX_new();
+      if (!EVP_DigestInit(r->d.md, EVP_sha3_512())) {
+        crypto_digest_free(r);
+        return NULL;
+      }
+      break;
+#else /* !(defined(OPENSSL_HAS_SHA3)) */
+    case DIGEST_SHA3_256:
+      keccak_digest_init(&r->d.sha3, 256);
+      break;
+    case DIGEST_SHA3_512:
+      keccak_digest_init(&r->d.sha3, 512);
+      break;
+#endif /* defined(OPENSSL_HAS_SHA3) */
+    default:
+      tor_assert_unreached();
+    }
+
+  return r;
+}
+
+/** Allocate and return a new digest object to compute SHA1 digests.
+ */
+crypto_digest_t *
+crypto_digest_new(void)
+{
+  return crypto_digest_new_internal(DIGEST_SHA1);
+}
+
+/** Allocate and return a new digest object to compute 256-bit digests
+ * using <b>algorithm</b>.
+ *
+ * C_RUST_COUPLED: `external::crypto_digest::crypto_digest256_new`
+ * C_RUST_COUPLED: `crypto::digest::Sha256::default`
+ */
+crypto_digest_t *
+crypto_digest256_new(digest_algorithm_t algorithm)
+{
+  tor_assert(algorithm == DIGEST_SHA256 || algorithm == DIGEST_SHA3_256);
+  return crypto_digest_new_internal(algorithm);
+}
+
+/** Allocate and return a new digest object to compute 512-bit digests
+ * using <b>algorithm</b>. */
+crypto_digest_t *
+crypto_digest512_new(digest_algorithm_t algorithm)
+{
+  tor_assert(algorithm == DIGEST_SHA512 || algorithm == DIGEST_SHA3_512);
+  return crypto_digest_new_internal(algorithm);
+}
+
+/** Deallocate a digest object.
+ */
+void
+crypto_digest_free_(crypto_digest_t *digest)
+{
+  if (!digest)
+    return;
+#ifdef OPENSSL_HAS_SHA3
+  if (digest->algorithm == DIGEST_SHA3_256 ||
+      digest->algorithm == DIGEST_SHA3_512) {
+    if (digest->d.md) {
+      EVP_MD_CTX_free(digest->d.md);
+    }
+  }
+#endif /* defined(OPENSSL_HAS_SHA3) */
+  size_t bytes = crypto_digest_alloc_bytes(digest->algorithm);
+  memwipe(digest, 0, bytes);
+  tor_free(digest);
+}
+
+/** Add <b>len</b> bytes from <b>data</b> to the digest object.
+ *
+ * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_add_bytess`
+ * C_RUST_COUPLED: `crypto::digest::Sha256::process`
+ */
+void
+crypto_digest_add_bytes(crypto_digest_t *digest, const char *data,
+                        size_t len)
+{
+  tor_assert(digest);
+  tor_assert(data);
+  /* Using the SHA*_*() calls directly means we don't support doing
+   * SHA in hardware. But so far the delay of getting the question
+   * to the hardware, and hearing the answer, is likely higher than
+   * just doing it ourselves. Hashes are fast.
+   */
+  switch (digest->algorithm) {
+    case DIGEST_SHA1:
+      SHA1_Update(&digest->d.sha1, (void*)data, len);
+      break;
+    case DIGEST_SHA256:
+      SHA256_Update(&digest->d.sha2, (void*)data, len);
+      break;
+    case DIGEST_SHA512:
+      SHA512_Update(&digest->d.sha512, (void*)data, len);
+      break;
+#ifdef OPENSSL_HAS_SHA3
+    case DIGEST_SHA3_256: /* FALLSTHROUGH */
+    case DIGEST_SHA3_512: {
+      int r = EVP_DigestUpdate(digest->d.md, data, len);
+      tor_assert(r);
+  }
+      break;
+#else /* !(defined(OPENSSL_HAS_SHA3)) */
+    case DIGEST_SHA3_256: /* FALLSTHROUGH */
+    case DIGEST_SHA3_512:
+      keccak_digest_update(&digest->d.sha3, (const uint8_t *)data, len);
+      break;
+#endif /* defined(OPENSSL_HAS_SHA3) */
+    default:
+      /* LCOV_EXCL_START */
+      tor_fragile_assert();
+      break;
+      /* LCOV_EXCL_STOP */
+  }
+}
+
+/** Compute the hash of the data that has been passed to the digest
+ * object; write the first out_len bytes of the result to <b>out</b>.
+ * <b>out_len</b> must be \<= DIGEST512_LEN.
+ *
+ * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_get_digest`
+ * C_RUST_COUPLED: `impl digest::FixedOutput for Sha256`
+ */
+void
+crypto_digest_get_digest(crypto_digest_t *digest,
+                         char *out, size_t out_len)
+{
+  unsigned char r[DIGEST512_LEN];
+  tor_assert(digest);
+  tor_assert(out);
+  tor_assert(out_len <= crypto_digest_algorithm_get_length(digest->algorithm));
+
+  /* The SHA-3 code handles copying into a temporary ctx, and also can handle
+   * short output buffers by truncating appropriately. */
+  if (digest->algorithm == DIGEST_SHA3_256 ||
+      digest->algorithm == DIGEST_SHA3_512) {
+#ifdef OPENSSL_HAS_SHA3
+    unsigned dlen = (unsigned)
+      crypto_digest_algorithm_get_length(digest->algorithm);
+    EVP_MD_CTX *tmp = EVP_MD_CTX_new();
+    EVP_MD_CTX_copy(tmp, digest->d.md);
+    memset(r, 0xff, sizeof(r));
+    int res = EVP_DigestFinal(tmp, r, &dlen);
+    EVP_MD_CTX_free(tmp);
+    tor_assert(res == 1);
+    goto done;
+#else /* !(defined(OPENSSL_HAS_SHA3)) */
+    /* Tiny-Keccak handles copying into a temporary ctx, and also can handle
+     * short output buffers by truncating appropriately. */
+    keccak_digest_sum(&digest->d.sha3, (uint8_t *)out, out_len);
+    return;
+#endif /* defined(OPENSSL_HAS_SHA3) */
+  }
+
+  const size_t alloc_bytes = crypto_digest_alloc_bytes(digest->algorithm);
+  crypto_digest_t tmpenv;
+  /* memcpy into a temporary ctx, since SHA*_Final clears the context */
+  memcpy(&tmpenv, digest, alloc_bytes);
+  switch (digest->algorithm) {
+    case DIGEST_SHA1:
+      SHA1_Final(r, &tmpenv.d.sha1);
+      break;
+    case DIGEST_SHA256:
+      SHA256_Final(r, &tmpenv.d.sha2);
+      break;
+    case DIGEST_SHA512:
+      SHA512_Final(r, &tmpenv.d.sha512);
+      break;
+//LCOV_EXCL_START
+    case DIGEST_SHA3_256: /* FALLSTHROUGH */
+    case DIGEST_SHA3_512:
+    default:
+      log_warn(LD_BUG, "Handling unexpected algorithm %d", digest->algorithm);
+      /* This is fatal, because it should never happen. */
+      tor_assert_unreached();
+      break;
+//LCOV_EXCL_STOP
+  }
+#ifdef OPENSSL_HAS_SHA3
+ done:
+#endif
+  memcpy(out, r, out_len);
+  memwipe(r, 0, sizeof(r));
+}
+
+/** Allocate and return a new digest object with the same state as
+ * <b>digest</b>
+ *
+ * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_dup`
+ * C_RUST_COUPLED: `impl Clone for crypto::digest::Sha256`
+ */
+crypto_digest_t *
+crypto_digest_dup(const crypto_digest_t *digest)
+{
+  tor_assert(digest);
+  const size_t alloc_bytes = crypto_digest_alloc_bytes(digest->algorithm);
+  crypto_digest_t *result = tor_memdup(digest, alloc_bytes);
+
+#ifdef OPENSSL_HAS_SHA3
+  if (digest->algorithm == DIGEST_SHA3_256 ||
+      digest->algorithm == DIGEST_SHA3_512) {
+    result->d.md = EVP_MD_CTX_new();
+    EVP_MD_CTX_copy(result->d.md, digest->d.md);
+  }
+#endif /* defined(OPENSSL_HAS_SHA3) */
+  return result;
+}
+
+/** Temporarily save the state of <b>digest</b> in <b>checkpoint</b>.
+ * Asserts that <b>digest</b> is a SHA1 digest object.
+ */
+void
+crypto_digest_checkpoint(crypto_digest_checkpoint_t *checkpoint,
+                         const crypto_digest_t *digest)
+{
+  const size_t bytes = crypto_digest_alloc_bytes(digest->algorithm);
+  tor_assert(bytes <= sizeof(checkpoint->mem));
+  memcpy(checkpoint->mem, digest, bytes);
+}
+
+/** Restore the state of  <b>digest</b> from <b>checkpoint</b>.
+ * Asserts that <b>digest</b> is a SHA1 digest object. Requires that the
+ * state was previously stored with crypto_digest_checkpoint() */
+void
+crypto_digest_restore(crypto_digest_t *digest,
+                      const crypto_digest_checkpoint_t *checkpoint)
+{
+  const size_t bytes = crypto_digest_alloc_bytes(digest->algorithm);
+  memcpy(digest, checkpoint->mem, bytes);
+}
+
+/** Replace the state of the digest object <b>into</b> with the state
+ * of the digest object <b>from</b>.  Requires that 'into' and 'from'
+ * have the same digest type.
+ */
+void
+crypto_digest_assign(crypto_digest_t *into,
+                     const crypto_digest_t *from)
+{
+  tor_assert(into);
+  tor_assert(from);
+  tor_assert(into->algorithm == from->algorithm);
+  const size_t alloc_bytes = crypto_digest_alloc_bytes(from->algorithm);
+
+#ifdef OPENSSL_HAS_SHA3
+  if (from->algorithm == DIGEST_SHA3_256 ||
+      from->algorithm == DIGEST_SHA3_512) {
+    EVP_MD_CTX_copy(into->d.md, from->d.md);
+    return;
+  }
+#endif /* defined(OPENSSL_HAS_SHA3) */
+
+  memcpy(into,from,alloc_bytes);
+}
+
+/** Given a list of strings in <b>lst</b>, set the <b>len_out</b>-byte digest
+ * at <b>digest_out</b> to the hash of the concatenation of those strings,
+ * plus the optional string <b>append</b>, computed with the algorithm
+ * <b>alg</b>.
+ * <b>out_len</b> must be \<= DIGEST512_LEN. */
+void
+crypto_digest_smartlist(char *digest_out, size_t len_out,
+                        const smartlist_t *lst,
+                        const char *append,
+                        digest_algorithm_t alg)
+{
+  crypto_digest_smartlist_prefix(digest_out, len_out, NULL, lst, append, alg);
+}
+
+/** Given a list of strings in <b>lst</b>, set the <b>len_out</b>-byte digest
+ * at <b>digest_out</b> to the hash of the concatenation of: the
+ * optional string <b>prepend</b>, those strings,
+ * and the optional string <b>append</b>, computed with the algorithm
+ * <b>alg</b>.
+ * <b>len_out</b> must be \<= DIGEST512_LEN. */
+void
+crypto_digest_smartlist_prefix(char *digest_out, size_t len_out,
+                        const char *prepend,
+                        const smartlist_t *lst,
+                        const char *append,
+                        digest_algorithm_t alg)
+{
+  crypto_digest_t *d = crypto_digest_new_internal(alg);
+  if (prepend)
+    crypto_digest_add_bytes(d, prepend, strlen(prepend));
+  SMARTLIST_FOREACH(lst, const char *, cp,
+                    crypto_digest_add_bytes(d, cp, strlen(cp)));
+  if (append)
+    crypto_digest_add_bytes(d, append, strlen(append));
+  crypto_digest_get_digest(d, digest_out, len_out);
+  crypto_digest_free(d);
+}
+
+/** Compute the HMAC-SHA-256 of the <b>msg_len</b> bytes in <b>msg</b>, using
+ * the <b>key</b> of length <b>key_len</b>.  Store the DIGEST256_LEN-byte
+ * result in <b>hmac_out</b>. Asserts on failure.
+ */
+void
+crypto_hmac_sha256(char *hmac_out,
+                   const char *key, size_t key_len,
+                   const char *msg, size_t msg_len)
+{
+  /* If we've got OpenSSL >=0.9.8 we can use its hmac implementation. */
+  tor_assert(key_len < INT_MAX);
+  tor_assert(msg_len < INT_MAX);
+  tor_assert(hmac_out);
+  unsigned char *rv = NULL;
+  rv = HMAC(EVP_sha256(), key, (int)key_len, (unsigned char*)msg, (int)msg_len,
+            (unsigned char*)hmac_out, NULL);
+  tor_assert(rv);
+}
+
diff --git a/src/lib/crypt_ops/crypto_ed25519.c b/src/lib/crypt_ops/crypto_ed25519.c
index 400f96389..058152912 100644
--- a/src/lib/crypt_ops/crypto_ed25519.c
+++ b/src/lib/crypt_ops/crypto_ed25519.c
@@ -226,7 +226,7 @@ ed25519_keypair_generate(ed25519_keypair_t *keypair_out, int extra_strong)
 int
 ed25519_public_key_is_zero(const ed25519_public_key_t *pubkey)
 {
-  return tor_mem_is_zero((char*)pubkey->pubkey, ED25519_PUBKEY_LEN);
+  return safe_mem_is_zero((char*)pubkey->pubkey, ED25519_PUBKEY_LEN);
 }
 
 /* Return a heap-allocated array that contains <b>msg</b> prefixed by the
diff --git a/src/lib/crypt_ops/crypto_format.c b/src/lib/crypt_ops/crypto_format.c
index 84f73e527..118cd7904 100644
--- a/src/lib/crypt_ops/crypto_format.c
+++ b/src/lib/crypt_ops/crypto_format.c
@@ -104,7 +104,7 @@ crypto_read_tagged_contents_from_file(const char *fname,
   prefix[32] = 0;
   /* Check type, extract tag. */
   if (strcmpstart(prefix, "== ") || strcmpend(prefix, " ==") ||
-      ! tor_mem_is_zero(prefix+strlen(prefix), 32-strlen(prefix))) {
+      ! fast_mem_is_zero(prefix+strlen(prefix), 32-strlen(prefix))) {
     saved_errno = EINVAL;
     goto end;
   }
@@ -131,20 +131,27 @@ crypto_read_tagged_contents_from_file(const char *fname,
   return r;
 }
 
-/** Encode <b>pkey</b> as a base64-encoded string, without trailing "="
+/** Encode <b>pkey</b> as a base64-encoded string, including trailing "="
  * characters, in the buffer <b>output</b>, which must have at least
- * CURVE25519_BASE64_PADDED_LEN+1 bytes available.  Return 0 on success, -1 on
- * failure. */
-int
+ * CURVE25519_BASE64_PADDED_LEN+1 bytes available.
+ * Can not fail.
+ *
+ * Careful! CURVE25519_BASE64_PADDED_LEN is one byte longer than
+ * ED25519_BASE64_LEN.
+ */
+void
 curve25519_public_to_base64(char *output,
                             const curve25519_public_key_t *pkey)
 {
   char buf[128];
-  base64_encode(buf, sizeof(buf),
-                (const char*)pkey->public_key, CURVE25519_PUBKEY_LEN, 0);
-  buf[CURVE25519_BASE64_PADDED_LEN] = '\0';
+  int n = base64_encode(buf, sizeof(buf),
+                        (const char*)pkey->public_key,
+                        CURVE25519_PUBKEY_LEN, 0);
+  /* These asserts should always succeed, unless there is a bug in
+   * base64_encode(). */
+  tor_assert(n == CURVE25519_BASE64_PADDED_LEN);
+  tor_assert(buf[CURVE25519_BASE64_PADDED_LEN] == '\0');
   memcpy(output, buf, CURVE25519_BASE64_PADDED_LEN+1);
-  return 0;
 }
 
 /** Try to decode a base64-encoded curve25519 public key from <b>input</b>
@@ -181,8 +188,7 @@ ed25519_fmt(const ed25519_public_key_t *pkey)
     if (ed25519_public_key_is_zero(pkey)) {
       strlcpy(formatted, "<unset>", sizeof(formatted));
     } else {
-      int r = ed25519_public_to_base64(formatted, pkey);
-      tor_assert(!r);
+      ed25519_public_to_base64(formatted, pkey);
     }
   } else {
     strlcpy(formatted, "<null>", sizeof(formatted));
@@ -202,28 +208,35 @@ ed25519_public_from_base64(ed25519_public_key_t *pkey,
 
 /** Encode the public key <b>pkey</b> into the buffer at <b>output</b>,
  * which must have space for ED25519_BASE64_LEN bytes of encoded key,
- * plus one byte for a terminating NUL.  Return 0 on success, -1 on failure.
+ * plus one byte for a terminating NUL.
+ * Can not fail.
+ *
+ * Careful! ED25519_BASE64_LEN is one byte shorter than
+ * CURVE25519_BASE64_PADDED_LEN.
  */
-int
+void
 ed25519_public_to_base64(char *output,
                          const ed25519_public_key_t *pkey)
 {
-  return digest256_to_base64(output, (const char *)pkey->pubkey);
+  digest256_to_base64(output, (const char *)pkey->pubkey);
 }
 
 /** Encode the signature <b>sig</b> into the buffer at <b>output</b>,
  * which must have space for ED25519_SIG_BASE64_LEN bytes of encoded signature,
- * plus one byte for a terminating NUL.  Return 0 on success, -1 on failure.
+ * plus one byte for a terminating NUL.
+ * Can not fail.
  */
-int
+void
 ed25519_signature_to_base64(char *output,
                             const ed25519_signature_t *sig)
 {
   char buf[256];
   int n = base64_encode_nopad(buf, sizeof(buf), sig->sig, ED25519_SIG_LEN);
+  /* These asserts should always succeed, unless there is a bug in
+   * base64_encode_nopad(). */
   tor_assert(n == ED25519_SIG_BASE64_LEN);
+  tor_assert(buf[ED25519_SIG_BASE64_LEN] == '\0');
   memcpy(output, buf, ED25519_SIG_BASE64_LEN+1);
-  return 0;
 }
 
 /** Try to decode the string <b>input</b> into an ed25519 signature. On
@@ -233,16 +246,11 @@ int
 ed25519_signature_from_base64(ed25519_signature_t *sig,
                               const char *input)
 {
-
   if (strlen(input) != ED25519_SIG_BASE64_LEN)
     return -1;
-  char buf[ED25519_SIG_BASE64_LEN+3];
-  memcpy(buf, input, ED25519_SIG_BASE64_LEN);
-  buf[ED25519_SIG_BASE64_LEN+0] = '=';
-  buf[ED25519_SIG_BASE64_LEN+1] = '=';
-  buf[ED25519_SIG_BASE64_LEN+2] = 0;
   char decoded[128];
-  int n = base64_decode(decoded, sizeof(decoded), buf, strlen(buf));
+  int n = base64_decode(decoded, sizeof(decoded), input,
+                        ED25519_SIG_BASE64_LEN);
   if (n < 0 || n != ED25519_SIG_LEN)
     return -1;
   memcpy(sig->sig, decoded, ED25519_SIG_LEN);
@@ -250,24 +258,26 @@ ed25519_signature_from_base64(ed25519_signature_t *sig,
   return 0;
 }
 
-/** Base64 encode DIGEST_LINE bytes from <b>digest</b>, remove the trailing =
+/** Base64 encode DIGEST_LEN bytes from <b>digest</b>, remove the trailing =
  * characters, and store the nul-terminated result in the first
- * BASE64_DIGEST_LEN+1 bytes of <b>d64</b>.  */
-/* XXXX unify with crypto_format.c code */
-int
+ * BASE64_DIGEST_LEN+1 bytes of <b>d64</b>.
+ * Can not fail. */
+void
 digest_to_base64(char *d64, const char *digest)
 {
   char buf[256];
-  base64_encode(buf, sizeof(buf), digest, DIGEST_LEN, 0);
-  buf[BASE64_DIGEST_LEN] = '\0';
+  int n = base64_encode_nopad(buf, sizeof(buf),
+                              (const uint8_t *)digest, DIGEST_LEN);
+  /* These asserts should always succeed, unless there is a bug in
+   * base64_encode_nopad(). */
+  tor_assert(n == BASE64_DIGEST_LEN);
+  tor_assert(buf[BASE64_DIGEST_LEN] == '\0');
   memcpy(d64, buf, BASE64_DIGEST_LEN+1);
-  return 0;
 }
 
 /** Given a base64 encoded, nul-terminated digest in <b>d64</b> (without
  * trailing newline or = characters), decode it and store the result in the
  * first DIGEST_LEN bytes at <b>digest</b>. */
-/* XXXX unify with crypto_format.c code */
 int
 digest_from_base64(char *digest, const char *d64)
 {
@@ -279,22 +289,24 @@ digest_from_base64(char *digest, const char *d64)
 
 /** Base64 encode DIGEST256_LINE bytes from <b>digest</b>, remove the
  * trailing = characters, and store the nul-terminated result in the first
- * BASE64_DIGEST256_LEN+1 bytes of <b>d64</b>. */
- /* XXXX unify with crypto_format.c code */
-int
+ * BASE64_DIGEST256_LEN+1 bytes of <b>d64</b>.
+ * Can not fail. */
+void
 digest256_to_base64(char *d64, const char *digest)
 {
   char buf[256];
-  base64_encode(buf, sizeof(buf), digest, DIGEST256_LEN, 0);
-  buf[BASE64_DIGEST256_LEN] = '\0';
+  int n = base64_encode_nopad(buf, sizeof(buf),
+                              (const uint8_t *)digest, DIGEST256_LEN);
+  /* These asserts should always succeed, unless there is a bug in
+   * base64_encode_nopad(). */
+  tor_assert(n == BASE64_DIGEST256_LEN);
+  tor_assert(buf[BASE64_DIGEST256_LEN] == '\0');
   memcpy(d64, buf, BASE64_DIGEST256_LEN+1);
-  return 0;
 }
 
 /** Given a base64 encoded, nul-terminated digest in <b>d64</b> (without
  * trailing newline or = characters), decode it and store the result in the
  * first DIGEST256_LEN bytes at <b>digest</b>. */
-/* XXXX unify with crypto_format.c code */
 int
 digest256_from_base64(char *digest, const char *d64)
 {
diff --git a/src/lib/crypt_ops/crypto_format.h b/src/lib/crypt_ops/crypto_format.h
index fe852e6a6..b4b3aa189 100644
--- a/src/lib/crypt_ops/crypto_format.h
+++ b/src/lib/crypt_ops/crypto_format.h
@@ -33,18 +33,18 @@ ssize_t crypto_read_tagged_contents_from_file(const char *fname,
 
 int ed25519_public_from_base64(struct ed25519_public_key_t *pkey,
                                const char *input);
-int ed25519_public_to_base64(char *output,
-                             const struct ed25519_public_key_t *pkey);
+void ed25519_public_to_base64(char *output,
+                              const struct ed25519_public_key_t *pkey);
 const char *ed25519_fmt(const struct ed25519_public_key_t *pkey);
 
 int ed25519_signature_from_base64(struct ed25519_signature_t *sig,
                                   const char *input);
-int ed25519_signature_to_base64(char *output,
-                                const struct ed25519_signature_t *sig);
+void ed25519_signature_to_base64(char *output,
+                                 const struct ed25519_signature_t *sig);
 
-int digest_to_base64(char *d64, const char *digest);
+void digest_to_base64(char *d64, const char *digest);
 int digest_from_base64(char *digest, const char *d64);
-int digest256_to_base64(char *d64, const char *digest);
+void digest256_to_base64(char *d64, const char *digest);
 int digest256_from_base64(char *digest, const char *d64);
 
 #endif /* !defined(TOR_CRYPTO_FORMAT_H) */
diff --git a/src/lib/crypt_ops/crypto_hkdf.c b/src/lib/crypt_ops/crypto_hkdf.c
index fd2e70165..e0f3d65ad 100644
--- a/src/lib/crypt_ops/crypto_hkdf.c
+++ b/src/lib/crypt_ops/crypto_hkdf.c
@@ -25,7 +25,7 @@
 #include <openssl/kdf.h>
 #define HAVE_OPENSSL_HKDF 1
 #endif
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 #include <string.h>
 
@@ -109,7 +109,7 @@ crypto_expand_key_material_rfc5869_sha256_openssl(
   return 0;
 }
 
-#else
+#else /* !(defined(HAVE_OPENSSL_HKDF)) */
 
 /**
  * Perform RFC5869 HKDF computation using our own legacy implementation.
@@ -166,7 +166,7 @@ crypto_expand_key_material_rfc5869_sha256_legacy(
   memwipe(mac, 0, sizeof(mac));
   return 0;
 }
-#endif
+#endif /* defined(HAVE_OPENSSL_HKDF) */
 
 /** Expand some secret key material according to RFC5869, using SHA256 as the
  * underlying hash.  The <b>key_in_len</b> bytes at <b>key_in</b> are the
@@ -191,11 +191,11 @@ crypto_expand_key_material_rfc5869_sha256(
                                              salt_in_len, info_in,
                                              info_in_len,
                                              key_out, key_out_len);
-#else
+#else /* !(defined(HAVE_OPENSSL_HKDF)) */
   return crypto_expand_key_material_rfc5869_sha256_legacy(key_in,
                                                key_in_len, salt_in,
                                                salt_in_len, info_in,
                                                info_in_len,
                                                key_out, key_out_len);
-#endif
+#endif /* defined(HAVE_OPENSSL_HKDF) */
 }
diff --git a/src/lib/crypt_ops/crypto_init.c b/src/lib/crypt_ops/crypto_init.c
index 4040085c7..a16bf4e11 100644
--- a/src/lib/crypt_ops/crypto_init.c
+++ b/src/lib/crypt_ops/crypto_init.c
@@ -12,6 +12,8 @@
 
 #include "orconfig.h"
 
+#define CRYPTO_PRIVATE
+
 #include "lib/crypt_ops/crypto_init.h"
 
 #include "lib/crypt_ops/crypto_curve25519.h"
@@ -69,6 +71,8 @@ crypto_early_init(void)
     if (crypto_init_siphash_key() < 0)
       return -1;
 
+    crypto_rand_fast_init();
+
     curve25519_init();
     ed25519_init();
   }
@@ -95,7 +99,7 @@ crypto_global_init(int useAccel, const char *accelName, const char *accelDir)
     (void)useAccel;
     (void)accelName;
     (void)accelDir;
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 #ifdef ENABLE_NSS
     if (crypto_nss_late_init() < 0)
       return -1;
@@ -111,6 +115,7 @@ crypto_thread_cleanup(void)
 #ifdef ENABLE_OPENSSL
   crypto_openssl_thread_cleanup();
 #endif
+  destroy_thread_fast_rng();
 }
 
 /**
@@ -129,6 +134,8 @@ crypto_global_cleanup(void)
   crypto_nss_global_cleanup();
 #endif
 
+  crypto_rand_fast_shutdown();
+
   crypto_early_initialized_ = 0;
   crypto_global_initialized_ = 0;
   have_seeded_siphash = 0;
@@ -145,6 +152,12 @@ crypto_prefork(void)
 #ifdef ENABLE_NSS
   crypto_nss_prefork();
 #endif
+  /* It is not safe to share a fast_rng object across a fork boundary unless
+   * we actually have zero-on-fork support in map_anon.c.  If we have
+   * drop-on-fork support, we will crash; if we have neither, we will yield
+   * a copy of the parent process's rng, which is scary and insecure.
+   */
+  destroy_thread_fast_rng();
 }
 
 /** Run operations that the crypto library requires to be happy again
diff --git a/src/lib/crypt_ops/crypto_init.h b/src/lib/crypt_ops/crypto_init.h
index 540d08eb5..8de3eb03e 100644
--- a/src/lib/crypt_ops/crypto_init.h
+++ b/src/lib/crypt_ops/crypto_init.h
@@ -33,4 +33,4 @@ const char *crypto_get_header_version_string(void);
 
 int tor_is_using_nss(void);
 
-#endif /* !defined(TOR_CRYPTO_H) */
+#endif /* !defined(TOR_CRYPTO_INIT_H) */
diff --git a/src/lib/crypt_ops/crypto_nss_mgt.h b/src/lib/crypt_ops/crypto_nss_mgt.h
index 72fd2a122..4cfa9b42a 100644
--- a/src/lib/crypt_ops/crypto_nss_mgt.h
+++ b/src/lib/crypt_ops/crypto_nss_mgt.h
@@ -29,6 +29,6 @@ void crypto_nss_global_cleanup(void);
 
 void crypto_nss_prefork(void);
 void crypto_nss_postfork(void);
-#endif
+#endif /* defined(ENABLE_NSS) */
 
-#endif /* !defined(TOR_CRYPTO_NSS_H) */
+#endif /* !defined(TOR_CRYPTO_NSS_MGT_H) */
diff --git a/src/lib/crypt_ops/crypto_ope.c b/src/lib/crypt_ops/crypto_ope.c
index 2186d2a93..4bd4b3570 100644
--- a/src/lib/crypt_ops/crypto_ope.c
+++ b/src/lib/crypt_ops/crypto_ope.c
@@ -57,9 +57,9 @@ ope_val_from_le(ope_val_t x)
     ((x) >> 8) |
     (((x)&0xff) << 8);
 }
-#else
+#else /* !(defined(WORDS_BIGENDIAN)) */
 #define ope_val_from_le(x) (x)
-#endif
+#endif /* defined(WORDS_BIGENDIAN) */
 
 /**
  * Return a new AES256-CTR stream cipher object for <b>ope</b>, ready to yield
diff --git a/src/lib/crypt_ops/crypto_ope.h b/src/lib/crypt_ops/crypto_ope.h
index 610d95633..9778dfe0f 100644
--- a/src/lib/crypt_ops/crypto_ope.h
+++ b/src/lib/crypt_ops/crypto_ope.h
@@ -41,6 +41,6 @@ struct aes_cnt_cipher;
 STATIC struct aes_cnt_cipher *ope_get_cipher(const crypto_ope_t *ope,
                                               uint32_t initial_idx);
 STATIC uint64_t sum_values_from_cipher(struct aes_cnt_cipher *c, size_t n);
-#endif
+#endif /* defined(CRYPTO_OPE_PRIVATE) */
 
-#endif
+#endif /* !defined(CRYPTO_OPE_H) */
diff --git a/src/lib/crypt_ops/crypto_openssl_mgt.c b/src/lib/crypt_ops/crypto_openssl_mgt.c
index 60e4ea795..9ec59e7c8 100644
--- a/src/lib/crypt_ops/crypto_openssl_mgt.c
+++ b/src/lib/crypt_ops/crypto_openssl_mgt.c
@@ -200,10 +200,10 @@ crypto_openssl_early_init(void)
                      OPENSSL_INIT_LOAD_CRYPTO_STRINGS |
                      OPENSSL_INIT_ADD_ALL_CIPHERS |
                      OPENSSL_INIT_ADD_ALL_DIGESTS, NULL);
-#else
+#else /* !(defined(OPENSSL_1_1_API)) */
     ERR_load_crypto_strings();
     OpenSSL_add_all_algorithms();
-#endif
+#endif /* defined(OPENSSL_1_1_API) */
 
     setup_openssl_threading();
 
@@ -213,6 +213,14 @@ crypto_openssl_early_init(void)
         !strcmp(version_str, OPENSSL_VERSION_TEXT)) {
       log_info(LD_CRYPTO, "OpenSSL version matches version from headers "
                  "(%lx: %s).", version_num, version_str);
+    } else if ((version_num & 0xffff0000) ==
+               (OPENSSL_VERSION_NUMBER & 0xffff0000)) {
+      log_notice(LD_CRYPTO,
+               "We compiled with OpenSSL %lx: %s and we "
+               "are running with OpenSSL %lx: %s. "
+               "These two versions should be binary compatible.",
+               (unsigned long)OPENSSL_VERSION_NUMBER, OPENSSL_VERSION_TEXT,
+               version_num, version_str);
     } else {
       log_warn(LD_CRYPTO, "OpenSSL version from headers does not match the "
                "version we're running with. If you get weird crashes, that "
diff --git a/src/lib/crypt_ops/crypto_openssl_mgt.h b/src/lib/crypt_ops/crypto_openssl_mgt.h
index a3dd03aa0..111a2d12e 100644
--- a/src/lib/crypt_ops/crypto_openssl_mgt.h
+++ b/src/lib/crypt_ops/crypto_openssl_mgt.h
@@ -84,6 +84,6 @@ int crypto_openssl_late_init(int useAccel, const char *accelName,
 void crypto_openssl_thread_cleanup(void);
 void crypto_openssl_global_cleanup(void);
 
-#endif /* ENABLE_OPENSSL */
+#endif /* defined(ENABLE_OPENSSL) */
 
 #endif /* !defined(TOR_CRYPTO_OPENSSL_H) */
diff --git a/src/lib/crypt_ops/crypto_rand.c b/src/lib/crypt_ops/crypto_rand.c
index 0b1cb96c1..a80a98f26 100644
--- a/src/lib/crypt_ops/crypto_rand.c
+++ b/src/lib/crypt_ops/crypto_rand.c
@@ -36,6 +36,7 @@
 
 #include "lib/defs/digest_sizes.h"
 #include "lib/crypt_ops/crypto_digest.h"
+#include "lib/ctime/di_ops.h"
 
 #ifdef ENABLE_NSS
 #include "lib/crypt_ops/crypto_nss_mgt.h"
@@ -46,7 +47,7 @@ DISABLE_GCC_WARNING(redundant-decls)
 #include <openssl/rand.h>
 #include <openssl/sha.h>
 ENABLE_GCC_WARNING(redundant-decls)
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 #ifdef ENABLE_NSS
 #include <pk11pub.h>
@@ -314,7 +315,7 @@ crypto_strongest_rand_raw(uint8_t *out, size_t out_len)
       }
     }
 
-    if ((out_len < sanity_min_size) || !tor_mem_is_zero((char*)out, out_len))
+    if ((out_len < sanity_min_size) || !safe_mem_is_zero((char*)out, out_len))
       return 0;
   }
 
@@ -418,7 +419,7 @@ crypto_seed_openssl_rng(void)
   else
     return -1;
 }
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 #ifdef ENABLE_NSS
 /**
@@ -441,7 +442,7 @@ crypto_seed_nss_rng(void)
 
   return load_entropy_ok ? 0 : -1;
 }
-#endif
+#endif /* defined(ENABLE_NSS) */
 
 /**
  * Seed the RNG for any and all crypto libraries that we're using with bytes
@@ -519,13 +520,13 @@ crypto_rand_unmocked(char *to, size_t n)
 
 #undef BUFLEN
   }
-#else
+#else /* !(defined(ENABLE_NSS)) */
   int r = RAND_bytes((unsigned char*)to, (int)n);
   /* We consider a PRNG failure non-survivable. Let's assert so that we get a
    * stack trace about where it happened.
    */
   tor_assert(r >= 0);
-#endif
+#endif /* defined(ENABLE_NSS) */
 }
 
 /**
@@ -626,6 +627,6 @@ crypto_force_rand_ssleay(void)
     RAND_set_rand_method(default_method);
     return 1;
   }
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
   return 0;
 }
diff --git a/src/lib/crypt_ops/crypto_rand.h b/src/lib/crypt_ops/crypto_rand.h
index 8a81a4acd..a019287aa 100644
--- a/src/lib/crypt_ops/crypto_rand.h
+++ b/src/lib/crypt_ops/crypto_rand.h
@@ -66,12 +66,37 @@ void crypto_fast_rng_free_(crypto_fast_rng_t *);
 
 unsigned crypto_fast_rng_get_uint(crypto_fast_rng_t *rng, unsigned limit);
 uint64_t crypto_fast_rng_get_uint64(crypto_fast_rng_t *rng, uint64_t limit);
+uint32_t crypto_fast_rng_get_u32(crypto_fast_rng_t *rng);
+uint64_t crypto_fast_rng_uint64_range(crypto_fast_rng_t *rng,
+                                      uint64_t min, uint64_t max);
 double crypto_fast_rng_get_double(crypto_fast_rng_t *rng);
 
+/**
+ * Using the fast_rng <b>rng</b>, yield true with probability
+ * 1/<b>n</b>. Otherwise yield false.
+ *
+ * <b>n</b> must not be zero.
+ **/
+#define crypto_fast_rng_one_in_n(rng, n)        \
+  (0 == (crypto_fast_rng_get_uint((rng), (n))))
+
+crypto_fast_rng_t *get_thread_fast_rng(void);
+
+#ifdef CRYPTO_PRIVATE
+/* These are only used from crypto_init.c */
+void destroy_thread_fast_rng(void);
+void crypto_rand_fast_init(void);
+void crypto_rand_fast_shutdown(void);
+#endif /* defined(CRYPTO_PRIVATE) */
+
 #if defined(TOR_UNIT_TESTS)
 /* Used for white-box testing */
 size_t crypto_fast_rng_get_bytes_used_per_stream(void);
-#endif
+/* For deterministic prng implementations */
+void crypto_fast_rng_disable_reseed(crypto_fast_rng_t *rng);
+/* To override the prng for testing. */
+crypto_fast_rng_t *crypto_replace_thread_fast_rng(crypto_fast_rng_t *rng);
+#endif /* defined(TOR_UNIT_TESTS) */
 
 #ifdef CRYPTO_RAND_PRIVATE
 
diff --git a/src/lib/crypt_ops/crypto_rand_fast.c b/src/lib/crypt_ops/crypto_rand_fast.c
index 34e763bf5..e6ceb42cc 100644
--- a/src/lib/crypt_ops/crypto_rand_fast.c
+++ b/src/lib/crypt_ops/crypto_rand_fast.c
@@ -33,6 +33,7 @@
  */
 
 #define CRYPTO_RAND_FAST_PRIVATE
+#define CRYPTO_PRIVATE
 
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/crypt_ops/crypto_cipher.h"
@@ -41,11 +42,29 @@
 #include "lib/intmath/cmp.h"
 #include "lib/cc/ctassert.h"
 #include "lib/malloc/map_anon.h"
+#include "lib/thread/threads.h"
 
 #include "lib/log/util_bug.h"
 
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
 #include <string.h>
 
+#ifdef NOINHERIT_CAN_FAIL
+#define CHECK_PID
+#endif
+
+#ifdef CHECK_PID
+#define PID_FIELD_LEN sizeof(pid_t)
+#else
+#define PID_FIELD_LEN 0
+#endif
+
 /* Alias for CRYPTO_FAST_RNG_SEED_LEN to make our code shorter.
  */
 #define SEED_LEN (CRYPTO_FAST_RNG_SEED_LEN)
@@ -57,7 +76,7 @@
 /* The number of random bytes that we can yield to the user after each
  * time we fill a crypto_fast_rng_t's buffer.
  */
-#define BUFLEN (MAPLEN - 2*sizeof(uint16_t) - SEED_LEN)
+#define BUFLEN (MAPLEN - 2*sizeof(uint16_t) - SEED_LEN - PID_FIELD_LEN)
 
 /* The number of buffer refills after which we should fetch more
  * entropy from crypto_strongest_rand().
@@ -76,10 +95,20 @@ CTASSERT(KEY_BITS == 128 || KEY_BITS == 192 || KEY_BITS == 256);
 
 struct crypto_fast_rng_t {
   /** How many more fills does this buffer have before we should mix
-   * in the output of crypto_rand()? */
-  uint16_t n_till_reseed;
+   * in the output of crypto_strongest_rand()?
+   *
+   * This value may be negative if unit tests are enabled.  If so, it
+   * indicates that we should never mix in extra data from
+   * crypto_strongest_rand().
+   */
+  int16_t n_till_reseed;
   /** How many bytes are remaining in cbuf.bytes? */
   uint16_t bytes_left;
+#ifdef CHECK_PID
+  /** Which process owns this fast_rng?  If this value is zero, we do not
+   * need to test the owner. */
+  pid_t owner;
+#endif
   struct cbuf {
     /** The seed (key and IV) that we will use the next time that we refill
      * cbuf. */
@@ -122,24 +151,57 @@ crypto_fast_rng_new(void)
  * long.
  *
  * Note that this object is NOT thread-safe.  If you need a thread-safe
- * prng, use crypto_rand(), or wrap this in a mutex.
+ * prng, you should probably look at get_thread_fast_rng().  Alternatively,
+ * use crypto_rand(), wrap this in a mutex.
  **/
 crypto_fast_rng_t *
 crypto_fast_rng_new_from_seed(const uint8_t *seed)
 {
+  unsigned inherit = INHERIT_RES_KEEP;
   /* We try to allocate this object as securely as we can, to avoid
    * having it get dumped, swapped, or shared after fork.
    */
   crypto_fast_rng_t *result = tor_mmap_anonymous(sizeof(*result),
-                                ANONMAP_PRIVATE | ANONMAP_NOINHERIT);
-
+                                ANONMAP_PRIVATE | ANONMAP_NOINHERIT,
+                                &inherit);
   memcpy(result->buf.seed, seed, SEED_LEN);
   /* Causes an immediate refill once the user asks for data. */
   result->bytes_left = 0;
   result->n_till_reseed = RESEED_AFTER;
+#ifdef CHECK_PID
+  if (inherit == INHERIT_RES_KEEP) {
+    /* This value will neither be dropped nor zeroed after fork, so we need to
+     * check our pid to make sure we are not sharing it across a fork.  This
+     * can be expensive if the pid value isn't cached, sadly.
+     */
+    result->owner = getpid();
+  }
+#elif defined(_WIN32)
+  /* Windows can't fork(), so there's no need to noinherit. */
+#else
+  /* We decided above that noinherit would always do _something_. Assert here
+   * that we were correct. */
+  tor_assertf(inherit != INHERIT_RES_KEEP,
+              "We failed to create a non-inheritable memory region, even "
+              "though we believed such a failure to be impossible! This is "
+              "probably a bug in Tor support for your platform; please report "
+              "it.");
+#endif /* defined(CHECK_PID) || ... */
   return result;
 }
 
+#ifdef TOR_UNIT_TESTS
+/**
+ * Unit tests only: prevent a crypto_fast_rng_t from ever mixing in more
+ * entropy.
+ */
+void
+crypto_fast_rng_disable_reseed(crypto_fast_rng_t *rng)
+{
+  rng->n_till_reseed = -1;
+}
+#endif /* defined(TOR_UNIT_TESTS) */
+
 /**
  * Helper: create a crypto_cipher_t object from SEED_LEN bytes of
  * input.  The first KEY_LEN bytes are used as the stream cipher's key,
@@ -152,6 +214,26 @@ cipher_from_seed(const uint8_t *seed)
 }
 
 /**
+ * Helper: mix additional entropy into <b>rng</b> by using our XOF to mix the
+ * old value for the seed with some additional bytes from
+ * crypto_strongest_rand().
+ **/
+static void
+crypto_fast_rng_add_entopy(crypto_fast_rng_t *rng)
+{
+  crypto_xof_t *xof = crypto_xof_new();
+  crypto_xof_add_bytes(xof, rng->buf.seed, SEED_LEN);
+  {
+    uint8_t seedbuf[SEED_LEN];
+    crypto_strongest_rand(seedbuf, SEED_LEN);
+    crypto_xof_add_bytes(xof, seedbuf, SEED_LEN);
+    memwipe(seedbuf, 0, SEED_LEN);
+  }
+  crypto_xof_squeeze_bytes(xof, rng->buf.seed, SEED_LEN);
+  crypto_xof_free(xof);
+}
+
+/**
  * Helper: refill the seed bytes and output buffer of <b>rng</b>, using
  * the input seed bytes as input (key and IV) for the stream cipher.
  *
@@ -161,22 +243,19 @@ cipher_from_seed(const uint8_t *seed)
 static void
 crypto_fast_rng_refill(crypto_fast_rng_t *rng)
 {
-  if (rng->n_till_reseed-- == 0) {
-    /* It's time to reseed the RNG.  We'll do this by using our XOF to mix the
-     * old value for the seed with some additional bytes from
-     * crypto_strongest_rand(). */
-    crypto_xof_t *xof = crypto_xof_new();
-    crypto_xof_add_bytes(xof, rng->buf.seed, SEED_LEN);
-    {
-      uint8_t seedbuf[SEED_LEN];
-      crypto_strongest_rand(seedbuf, SEED_LEN);
-      crypto_xof_add_bytes(xof, seedbuf, SEED_LEN);
-      memwipe(seedbuf, 0, SEED_LEN);
-    }
-    crypto_xof_squeeze_bytes(xof, rng->buf.seed, SEED_LEN);
-    crypto_xof_free(xof);
-
+  rng->n_till_reseed--;
+  if (rng->n_till_reseed == 0) {
+    /* It's time to reseed the RNG. */
+    crypto_fast_rng_add_entopy(rng);
     rng->n_till_reseed = RESEED_AFTER;
+  } else if (rng->n_till_reseed < 0) {
+#ifdef TOR_UNIT_TESTS
+    /* Reseeding is disabled for testing; never do it on this prng. */
+    rng->n_till_reseed = -1;
+#else
+    /* If testing is disabled, this shouldn't be able to become negative. */
+    tor_assert_unreached();
+#endif /* defined(TOR_UNIT_TESTS) */
   }
   /* Now fill rng->buf with output from our stream cipher, initialized from
    * that seed value. */
@@ -208,6 +287,27 @@ static void
 crypto_fast_rng_getbytes_impl(crypto_fast_rng_t *rng, uint8_t *out,
                               const size_t n)
 {
+#ifdef CHECK_PID
+  if (rng->owner) {
+    /* Note that we only need to do this check when we have owner set: that
+     * is, when our attempt to block inheriting failed, and the result was
+     * INHERIT_RES_KEEP.
+     *
+     * If the result was INHERIT_RES_DROP, then any attempt to access the rng
+     * memory after forking will crash.
+     *
+     * If the result was INHERIT_RES_ZERO, then forking will set the bytes_left
+     * and n_till_reseed fields to zero.  This function will call
+     * crypto_fast_rng_refill(), which will in turn reseed the PRNG.
+     *
+     * So we only need to do this test in the case when mmap_anonymous()
+     * returned INHERIT_KEEP.  We avoid doing it needlessly, since getpid() is
+     * often a system call, and that can be slow.
+     */
+    tor_assert(rng->owner == getpid());
+  }
+#endif /* defined(CHECK_PID) */
+
   size_t bytes_to_yield = n;
 
   while (bytes_to_yield) {
@@ -260,4 +360,80 @@ crypto_fast_rng_get_bytes_used_per_stream(void)
 {
   return BUFLEN;
 }
-#endif
+#endif /* defined(TOR_UNIT_TESTS) */
+
+/**
+ * Thread-local instance for our fast RNG.
+ **/
+static tor_threadlocal_t thread_rng;
+
+/**
+ * Return a per-thread fast RNG, initializing it if necessary.
+ *
+ * You do not need to free this yourself.
+ *
+ * It is NOT safe to share this value across threads.
+ **/
+crypto_fast_rng_t *
+get_thread_fast_rng(void)
+{
+  crypto_fast_rng_t *rng = tor_threadlocal_get(&thread_rng);
+
+  if (PREDICT_UNLIKELY(rng == NULL)) {
+    rng = crypto_fast_rng_new();
+    tor_threadlocal_set(&thread_rng, rng);
+  }
+
+  return rng;
+}
+
+/**
+ * Used when a thread is exiting: free the per-thread fast RNG if needed.
+ * Invoked from the crypto subsystem's thread-cleanup code.
+ **/
+void
+destroy_thread_fast_rng(void)
+{
+  crypto_fast_rng_t *rng = tor_threadlocal_get(&thread_rng);
+  if (!rng)
+    return;
+  crypto_fast_rng_free(rng);
+  tor_threadlocal_set(&thread_rng, NULL);
+}
+
+#ifdef TOR_UNIT_TESTS
+/**
+ * Replace the current thread's rng with <b>rng</b>. For use by the
+ * unit tests only.  Returns the previous thread rng.
+ **/
+crypto_fast_rng_t *
+crypto_replace_thread_fast_rng(crypto_fast_rng_t *rng)
+{
+  crypto_fast_rng_t *old_rng =  tor_threadlocal_get(&thread_rng);
+  tor_threadlocal_set(&thread_rng, rng);
+  return old_rng;
+}
+#endif /* defined(TOR_UNIT_TESTS) */
+
+/**
+ * Initialize the global thread-local key that will be used to keep track
+ * of per-thread fast RNG instances.  Called from the crypto subsystem's
+ * initialization code.
+ **/
+void
+crypto_rand_fast_init(void)
+{
+  tor_threadlocal_init(&thread_rng);
+}
+
+/**
+ * Initialize the global thread-local key that will be used to keep track
+ * of per-thread fast RNG instances.  Called from the crypto subsystem's
+ * shutdown code.
+ **/
+void
+crypto_rand_fast_shutdown(void)
+{
+  destroy_thread_fast_rng();
+  tor_threadlocal_destroy(&thread_rng);
+}
diff --git a/src/lib/crypt_ops/crypto_rand_numeric.c b/src/lib/crypt_ops/crypto_rand_numeric.c
index d02c5cdcf..ffbfa2d56 100644
--- a/src/lib/crypt_ops/crypto_rand_numeric.c
+++ b/src/lib/crypt_ops/crypto_rand_numeric.c
@@ -155,7 +155,34 @@ crypto_fast_rng_get_uint64(crypto_fast_rng_t *rng, uint64_t limit)
 }
 
 /**
- * As crypto_rand_, but extract the result from a crypto_fast_rng_t.
+ * As crypto_rand_u32, but extract the result from a crypto_fast_rng_t.
+ */
+uint32_t
+crypto_fast_rng_get_u32(crypto_fast_rng_t *rng)
+{
+  uint32_t val;
+  crypto_fast_rng_getbytes(rng, (void*)&val, sizeof(val));
+  return val;
+}
+
+/**
+ * As crypto_rand_uint64_range(), but extract the result from a
+ * crypto_fast_rng_t.
+ */
+uint64_t
+crypto_fast_rng_uint64_range(crypto_fast_rng_t *rng,
+                             uint64_t min, uint64_t max)
+{
+  /* Handle corrupted input */
+  if (BUG(min >= max)) {
+    return min;
+  }
+
+  return min + crypto_fast_rng_get_uint64(rng, max - min);
+}
+
+/**
+ * As crypto_rand_get_double() but extract the result from a crypto_fast_rng_t.
  */
 double
 crypto_fast_rng_get_double(crypto_fast_rng_t *rng)
@@ -164,3 +191,4 @@ crypto_fast_rng_get_double(crypto_fast_rng_t *rng)
   crypto_fast_rng_getbytes(rng, (void*)&u, sizeof(u));
   return ((double)u) / UINT_MAX_AS_DOUBLE;
 }
+
diff --git a/src/lib/crypt_ops/crypto_rsa.c b/src/lib/crypt_ops/crypto_rsa.c
index c9189b0df..c39d2e18d 100644
--- a/src/lib/crypt_ops/crypto_rsa.c
+++ b/src/lib/crypt_ops/crypto_rsa.c
@@ -59,7 +59,7 @@ crypto_get_rsa_padding(int padding)
     default: tor_assert(0); return -1; // LCOV_EXCL_LINE
     }
 }
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 /** Compare the public-key components of a and b.  Return non-zero iff
  * a==b.  A NULL key is considered to be distinct from all non-NULL
diff --git a/src/lib/crypt_ops/crypto_rsa.h b/src/lib/crypt_ops/crypto_rsa.h
index c1ea767f8..e9bfec2f8 100644
--- a/src/lib/crypt_ops/crypto_rsa.h
+++ b/src/lib/crypt_ops/crypto_rsa.h
@@ -119,7 +119,7 @@ struct rsa_st *crypto_pk_get_openssl_rsa_(crypto_pk_t *env);
 crypto_pk_t *crypto_new_pk_from_openssl_rsa_(struct rsa_st *rsa);
 MOCK_DECL(struct evp_pkey_st *, crypto_pk_get_openssl_evp_pkey_,(
                                  crypto_pk_t *env,int private));
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 #ifdef ENABLE_NSS
 struct SECKEYPublicKeyStr;
@@ -129,7 +129,7 @@ const struct SECKEYPublicKeyStr *crypto_pk_get_nss_pubkey(
                                            const crypto_pk_t *key);
 const struct SECKEYPrivateKeyStr *crypto_pk_get_nss_privkey(
                                            const crypto_pk_t *key);
-#endif
+#endif /* defined(ENABLE_NSS) */
 
 void crypto_pk_assign_public(crypto_pk_t *dest, const crypto_pk_t *src);
 void crypto_pk_assign_private(crypto_pk_t *dest, const crypto_pk_t *src);
@@ -140,6 +140,6 @@ struct SECItemStr;
 STATIC int secitem_uint_cmp(const struct SECItemStr *a,
                             const struct SECItemStr *b);
 #endif
-#endif
+#endif /* defined(TOR_UNIT_TESTS) */
 
-#endif
+#endif /* !defined(TOR_CRYPTO_RSA_H) */
diff --git a/src/lib/crypt_ops/crypto_rsa_nss.c b/src/lib/crypt_ops/crypto_rsa_nss.c
index ad2ad38b6..612b7a0e6 100644
--- a/src/lib/crypt_ops/crypto_rsa_nss.c
+++ b/src/lib/crypt_ops/crypto_rsa_nss.c
@@ -156,7 +156,7 @@ crypto_pk_get_openssl_evp_pkey_,(crypto_pk_t *pk, int private))
   tor_free(buf);
   return result;
 }
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 /** Allocate and return storage for a public key.  The key itself will not yet
  * be set.
diff --git a/src/lib/crypt_ops/crypto_s2k.c b/src/lib/crypt_ops/crypto_s2k.c
index 42276597d..5cf98e3e6 100644
--- a/src/lib/crypt_ops/crypto_s2k.c
+++ b/src/lib/crypt_ops/crypto_s2k.c
@@ -285,7 +285,7 @@ secret_to_key_compute_key(uint8_t *key_out, size_t key_out_len,
       if (rv < 0)
         return S2K_FAILED;
       return (int)key_out_len;
-#else
+#else /* !(defined(ENABLE_OPENSSL)) */
       SECItem passItem = { .type = siBuffer,
                            .data = (unsigned char *) secret,
                            .len = (int)secret_len };
@@ -325,7 +325,7 @@ secret_to_key_compute_key(uint8_t *key_out, size_t key_out_len,
       if (alg)
         SECOID_DestroyAlgorithmID(alg, PR_TRUE);
       return rv;
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
     }
 
     case S2K_TYPE_SCRYPT: {
diff --git a/src/lib/crypt_ops/crypto_util.c b/src/lib/crypt_ops/crypto_util.c
index 67a1a9eb9..5e3f4a87a 100644
--- a/src/lib/crypt_ops/crypto_util.c
+++ b/src/lib/crypt_ops/crypto_util.c
@@ -30,7 +30,7 @@ DISABLE_GCC_WARNING(redundant-decls)
 #include <openssl/err.h>
 #include <openssl/crypto.h>
 ENABLE_GCC_WARNING(redundant-decls)
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 #include "lib/log/log.h"
 #include "lib/log/util_bug.h"
diff --git a/src/lib/crypt_ops/digestset.h b/src/lib/crypt_ops/digestset.h
index 91d53a054..7d6d68734 100644
--- a/src/lib/crypt_ops/digestset.h
+++ b/src/lib/crypt_ops/digestset.h
@@ -26,4 +26,4 @@ void digestset_add(digestset_t *set, const char *addr);
 int digestset_probably_contains(const digestset_t *set,
                                 const char *addr);
 
-#endif
+#endif /* !defined(TOR_DIGESTSET_H) */
diff --git a/src/lib/crypt_ops/include.am b/src/lib/crypt_ops/include.am
index 473044014..1f58a33d3 100644
--- a/src/lib/crypt_ops/include.am
+++ b/src/lib/crypt_ops/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-crypt-ops-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_crypt_ops_a_SOURCES =			\
 	src/lib/crypt_ops/crypto_cipher.c		\
 	src/lib/crypt_ops/crypto_curve25519.c		\
@@ -27,12 +28,14 @@ src_lib_libtor_crypt_ops_a_SOURCES =			\
 if USE_NSS
 src_lib_libtor_crypt_ops_a_SOURCES +=			\
 	src/lib/crypt_ops/aes_nss.c			\
+	src/lib/crypt_ops/crypto_digest_nss.c		\
 	src/lib/crypt_ops/crypto_dh_nss.c		\
 	src/lib/crypt_ops/crypto_nss_mgt.c		\
 	src/lib/crypt_ops/crypto_rsa_nss.c
 else
 src_lib_libtor_crypt_ops_a_SOURCES +=			\
 	src/lib/crypt_ops/aes_openssl.c			\
+	src/lib/crypt_ops/crypto_digest_openssl.c	\
 	src/lib/crypt_ops/crypto_rsa_openssl.c
 endif
 
@@ -50,6 +53,7 @@ src_lib_libtor_crypt_ops_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_crypt_ops_testing_a_CFLAGS = \
 	$(AM_CFLAGS) $(TOR_CFLAGS_CRYPTLIB) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/crypt_ops/aes.h				\
 	src/lib/crypt_ops/compat_openssl.h		\
diff --git a/src/lib/ctime/include.am b/src/lib/ctime/include.am
index b46c43ba0..83942ca4e 100644
--- a/src/lib/ctime/include.am
+++ b/src/lib/ctime/include.am
@@ -11,6 +11,7 @@ else
 mulodi4_source=
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_ctime_a_SOURCES =			\
 	$(mulodi4_source) 				\
 	src/ext/csiphash.c   				\
@@ -21,5 +22,6 @@ src_lib_libtor_ctime_testing_a_SOURCES = \
 src_lib_libtor_ctime_a_CFLAGS = @CFLAGS_CONSTTIME@
 src_lib_libtor_ctime_testing_a_CFLAGS = @CFLAGS_CONSTTIME@ $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS += \
 	src/lib/ctime/di_ops.h
diff --git a/src/lib/defs/dh_sizes.h b/src/lib/defs/dh_sizes.h
index a2ffbc51c..b0d1eba0c 100644
--- a/src/lib/defs/dh_sizes.h
+++ b/src/lib/defs/dh_sizes.h
@@ -19,4 +19,4 @@
 /** Length of our legacy DH keys. */
 #define DH1024_KEY_LEN (1024/8)
 
-#endif
+#endif /* !defined(TOR_DH_SIZES_H) */
diff --git a/src/lib/defs/digest_sizes.h b/src/lib/defs/digest_sizes.h
index 525e5209d..a0dd97a74 100644
--- a/src/lib/defs/digest_sizes.h
+++ b/src/lib/defs/digest_sizes.h
@@ -24,4 +24,4 @@
 /** Length of the output of our 64-bit optimized message digests (SHA512). */
 #define DIGEST512_LEN 64
 
-#endif
+#endif /* !defined(TOR_DIGEST_SIZES_H) */
diff --git a/src/lib/defs/include.am b/src/lib/defs/include.am
index 6a7f9114e..84ee40377 100644
--- a/src/lib/defs/include.am
+++ b/src/lib/defs/include.am
@@ -1,6 +1,8 @@
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS += 			\
 	src/lib/defs/dh_sizes.h 	\
 	src/lib/defs/digest_sizes.h	\
+	src/lib/defs/logging_types.h	\
 	src/lib/defs/time.h      	\
 	src/lib/defs/x25519_sizes.h
diff --git a/src/lib/defs/logging_types.h b/src/lib/defs/logging_types.h
new file mode 100644
index 000000000..57db81800
--- /dev/null
+++ b/src/lib/defs/logging_types.h
@@ -0,0 +1,23 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file logging_types.h
+ *
+ * \brief Global definition for types used by logging systems.
+ **/
+
+#ifndef TOR_LOGGING_TYPES_H
+#define TOR_LOGGING_TYPES_H
+
+/* We define this here so that it can be used both by backtrace.h and
+ * log.h.
+ */
+
+/** Mask of zero or more log domains, OR'd together. */
+typedef uint64_t log_domain_mask_t;
+
+#endif
diff --git a/src/lib/defs/time.h b/src/lib/defs/time.h
index c25f5022c..459afbf42 100644
--- a/src/lib/defs/time.h
+++ b/src/lib/defs/time.h
@@ -20,4 +20,4 @@
 /* How many nanoseconds per millisecond */
 #define TOR_NSEC_PER_MSEC (1000*1000)
 
-#endif
+#endif /* !defined(TOR_TIME_DEFS_H) */
diff --git a/src/lib/defs/x25519_sizes.h b/src/lib/defs/x25519_sizes.h
index 8933a8866..6431f0a2d 100644
--- a/src/lib/defs/x25519_sizes.h
+++ b/src/lib/defs/x25519_sizes.h
@@ -33,4 +33,4 @@
 #define ED25519_BASE64_LEN 43
 #define ED25519_SIG_BASE64_LEN 86
 
-#endif
+#endif /* !defined(TOR_X25519_SIZES_H) */
diff --git a/src/lib/dispatch/.may_include b/src/lib/dispatch/.may_include
new file mode 100644
index 000000000..7f2df5859
--- /dev/null
+++ b/src/lib/dispatch/.may_include
@@ -0,0 +1,10 @@
+orconfig.h
+
+ext/tor_queue.h
+
+lib/cc/*.h
+lib/container/*.h
+lib/dispatch/*.h
+lib/intmath/*.h
+lib/log/*.h
+lib/malloc/*.h
diff --git a/src/lib/dispatch/dispatch.h b/src/lib/dispatch/dispatch.h
new file mode 100644
index 000000000..a9e655409
--- /dev/null
+++ b/src/lib/dispatch/dispatch.h
@@ -0,0 +1,114 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_DISPATCH_H
+#define TOR_DISPATCH_H
+
+#include "lib/dispatch/msgtypes.h"
+
+/**
+ * \file dispatch.h
+ * \brief Low-level APIs for message-passing system.
+ *
+ * This module implements message dispatch based on a set of short integer
+ * identifiers.  For a higher-level interface, see pubsub.h.
+ *
+ * Each message is represented as a generic msg_t object, and is discriminated
+ * by its message_id_t.  Messages are delivered by a dispatch_t object, which
+ * delivers each message to its recipients by a configured "channel".
+ *
+ * A "channel" is a means of delivering messages.  Every message_id_t must
+ * be associated with exactly one channel, identified by channel_id_t.
+ * When a channel receives messages, a callback is invoked to either process
+ * the messages immediately, or to cause them to be processed later.
+ *
+ * Every message_id_t has zero or more associated receiver functions set up in
+ * the dispatch_t object.  Once the dispatch_t object is created, receivers
+ * can be enabled or disabled [TODO], but not added or removed.
+ *
+ * Every message_id_t has an associated datatype, identified by a
+ * msg_type_id_t.  These datatypes can be associated with functions to
+ * (for example) free them, or format them for debugging.
+ *
+ * To setup a dispatch_t object, first create a dispatch_cfg_t object, and
+ * configure messages with their types, channels, and receivers.  Then, use
+ * dispatch_new() with that dispatch_cfg_t to create the dispatch_t object.
+ *
+ * (We use a two-phase contruction procedure here to enable better static
+ * reasoning about publish/subscribe relationships.)
+ *
+ * Once you have a dispatch_t, you can queue messages on it with
+ * dispatch_send*(), and cause those messages to be delivered with
+ * dispatch_flush().
+ **/
+
+/**
+ * A "dispatcher" is the highest-level object; it handles making sure that
+ * messages are received and delivered properly.  Only the mainloop
+ * should handle this type directly.
+ */
+typedef struct dispatch_t dispatch_t;
+
+struct dispatch_cfg_t;
+
+dispatch_t *dispatch_new(const struct dispatch_cfg_t *cfg);
+
+/**
+ * Free a dispatcher.  Tor does this at exit.
+ */
+#define dispatch_free(d) \
+  FREE_AND_NULL(dispatch_t, dispatch_free_, (d))
+
+void dispatch_free_(dispatch_t *);
+
+int dispatch_send(dispatch_t *d,
+                  subsys_id_t sender,
+                  channel_id_t channel,
+                  message_id_t msg,
+                  msg_type_id_t type,
+                  msg_aux_data_t auxdata);
+
+int dispatch_send_msg(dispatch_t *d, msg_t *m);
+
+int dispatch_send_msg_unchecked(dispatch_t *d, msg_t *m);
+
+/* Flush up to <b>max_msgs</b> currently pending messages from the
+ * dispatcher.  Messages that are not pending when this function are
+ * called, are not flushed by this call.  Return 0 on success, -1 on
+ * unrecoverable error.
+ */
+int dispatch_flush(dispatch_t *, channel_id_t chan, int max_msgs);
+
+/**
+ * Function callback type used to alert some other module when a channel's
+ * queue changes from empty to nonempty.
+ *
+ * Ex 1: To cause messages to be processed immediately on-stack, this callback
+ * should invoke dispatch_flush() directly.
+ *
+ * Ex 2: To cause messages to be processed very soon, from the event queue,
+ * this callback should schedule an event callback to run dispatch_flush().
+ *
+ * Ex 3: To cause messages to be processed periodically, this function should
+ * do nothing, and a periodic event should invoke dispatch_flush().
+ **/
+typedef void (*dispatch_alertfn_t)(struct dispatch_t *,
+                                   channel_id_t, void *);
+
+int dispatch_set_alert_fn(dispatch_t *d, channel_id_t chan,
+                          dispatch_alertfn_t fn, void *userdata);
+
+#define dispatch_free_msg(d,msg)                                \
+  STMT_BEGIN {                                                  \
+    msg_t **msg_tmp_ptr__ = &(msg);                             \
+    dispatch_free_msg_((d), *msg_tmp_ptr__);                    \
+    *msg_tmp_ptr__= NULL;                                       \
+  } STMT_END
+void dispatch_free_msg_(const dispatch_t *d, msg_t *msg);
+
+char *dispatch_fmt_msg_data(const dispatch_t *d, const msg_t *msg);
+
+#endif /* !defined(TOR_DISPATCH_H) */
diff --git a/src/lib/dispatch/dispatch_cfg.c b/src/lib/dispatch/dispatch_cfg.c
new file mode 100644
index 000000000..b3a72ec22
--- /dev/null
+++ b/src/lib/dispatch/dispatch_cfg.c
@@ -0,0 +1,141 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file dispatch_cfg.c
+ * \brief Create and configure a dispatch_cfg_t.
+ *
+ * A dispatch_cfg_t object is used to configure a set of messages and
+ * associated information before creating a dispatch_t.
+ */
+
+#define DISPATCH_PRIVATE
+
+#include "orconfig.h"
+#include "lib/dispatch/dispatch_cfg.h"
+#include "lib/dispatch/dispatch_cfg_st.h"
+#include "lib/dispatch/dispatch.h"
+#include "lib/dispatch/dispatch_st.h"
+
+#include "lib/container/smartlist.h"
+#include "lib/malloc/malloc.h"
+
+/**
+ * Create and return a new dispatch_cfg_t.
+ **/
+dispatch_cfg_t *
+dcfg_new(void)
+{
+  dispatch_cfg_t *cfg = tor_malloc(sizeof(dispatch_cfg_t));
+  cfg->type_by_msg = smartlist_new();
+  cfg->chan_by_msg = smartlist_new();
+  cfg->fns_by_type = smartlist_new();
+  cfg->recv_by_msg = smartlist_new();
+  return cfg;
+}
+
+/**
+ * Associate a message with a datatype.  Return 0 on success, -1 if a
+ * different type was previously associated with the message ID.
+ **/
+int
+dcfg_msg_set_type(dispatch_cfg_t *cfg, message_id_t msg,
+                  msg_type_id_t type)
+{
+  smartlist_grow(cfg->type_by_msg, msg+1);
+  msg_type_id_t *oldval = smartlist_get(cfg->type_by_msg, msg);
+  if (oldval != NULL && *oldval != type) {
+    return -1;
+  }
+  if (!oldval)
+    smartlist_set(cfg->type_by_msg, msg, tor_memdup(&type, sizeof(type)));
+  return 0;
+}
+
+/**
+ * Associate a message with a channel.  Return 0 on success, -1 if a
+ * different channel was previously associated with the message ID.
+ **/
+int
+dcfg_msg_set_chan(dispatch_cfg_t *cfg, message_id_t msg,
+                  channel_id_t chan)
+{
+  smartlist_grow(cfg->chan_by_msg, msg+1);
+  channel_id_t *oldval = smartlist_get(cfg->chan_by_msg, msg);
+  if (oldval != NULL && *oldval != chan) {
+    return -1;
+  }
+  if (!oldval)
+    smartlist_set(cfg->chan_by_msg, msg, tor_memdup(&chan, sizeof(chan)));
+  return 0;
+}
+
+/**
+ * Associate a set of functions with a datatype. Return 0 on success, -1 if
+ * different functions were previously associated with the type.
+ **/
+int
+dcfg_type_set_fns(dispatch_cfg_t *cfg, msg_type_id_t type,
+                  const dispatch_typefns_t *fns)
+{
+  smartlist_grow(cfg->fns_by_type, type+1);
+  dispatch_typefns_t *oldfns = smartlist_get(cfg->fns_by_type, type);
+  if (oldfns && (oldfns->free_fn != fns->free_fn ||
+                 oldfns->fmt_fn != fns->fmt_fn))
+    return -1;
+  if (!oldfns)
+    smartlist_set(cfg->fns_by_type, type, tor_memdup(fns, sizeof(*fns)));
+  return 0;
+}
+
+/**
+ * Associate a receiver with a message ID.  Multiple receivers may be
+ * associated with a single messasge ID.
+ *
+ * Return 0 on success, on failure.
+ **/
+int
+dcfg_add_recv(dispatch_cfg_t *cfg, message_id_t msg,
+              subsys_id_t sys, recv_fn_t fn)
+{
+  smartlist_grow(cfg->recv_by_msg, msg+1);
+  smartlist_t *receivers = smartlist_get(cfg->recv_by_msg, msg);
+  if (!receivers) {
+    receivers = smartlist_new();
+    smartlist_set(cfg->recv_by_msg, msg, receivers);
+  }
+
+  dispatch_rcv_t *rcv = tor_malloc(sizeof(dispatch_rcv_t));
+  rcv->sys = sys;
+  rcv->enabled = true;
+  rcv->fn = fn;
+  smartlist_add(receivers, (void*)rcv);
+  return 0;
+}
+
+/** Helper: release all storage held by <b>cfg</b>. */
+void
+dcfg_free_(dispatch_cfg_t *cfg)
+{
+  if (!cfg)
+    return;
+
+  SMARTLIST_FOREACH(cfg->type_by_msg, msg_type_id_t *, id, tor_free(id));
+  SMARTLIST_FOREACH(cfg->chan_by_msg, channel_id_t *, id, tor_free(id));
+  SMARTLIST_FOREACH(cfg->fns_by_type, dispatch_typefns_t *, f, tor_free(f));
+  smartlist_free(cfg->type_by_msg);
+  smartlist_free(cfg->chan_by_msg);
+  smartlist_free(cfg->fns_by_type);
+  SMARTLIST_FOREACH_BEGIN(cfg->recv_by_msg, smartlist_t *, receivers) {
+    if (!receivers)
+      continue;
+    SMARTLIST_FOREACH(receivers, dispatch_rcv_t *, rcv, tor_free(rcv));
+    smartlist_free(receivers);
+  } SMARTLIST_FOREACH_END(receivers);
+  smartlist_free(cfg->recv_by_msg);
+
+  tor_free(cfg);
+}
diff --git a/src/lib/dispatch/dispatch_cfg.h b/src/lib/dispatch/dispatch_cfg.h
new file mode 100644
index 000000000..61fade724
--- /dev/null
+++ b/src/lib/dispatch/dispatch_cfg.h
@@ -0,0 +1,39 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_DISPATCH_CFG_H
+#define TOR_DISPATCH_CFG_H
+
+#include "lib/dispatch/msgtypes.h"
+
+/**
+ * A "dispatch_cfg" is the configuration used to set up a dispatcher.
+ * It is created and accessed with a set of dcfg_* functions, and then
+ * used with dispatcher_new() to make the dispatcher.
+ */
+typedef struct dispatch_cfg_t dispatch_cfg_t;
+
+dispatch_cfg_t *dcfg_new(void);
+
+int dcfg_msg_set_type(dispatch_cfg_t *cfg, message_id_t msg,
+                      msg_type_id_t type);
+
+int dcfg_msg_set_chan(dispatch_cfg_t *cfg, message_id_t msg,
+                      channel_id_t chan);
+
+int dcfg_type_set_fns(dispatch_cfg_t *cfg, msg_type_id_t type,
+                      const dispatch_typefns_t *fns);
+
+int dcfg_add_recv(dispatch_cfg_t *cfg, message_id_t msg,
+                  subsys_id_t sys, recv_fn_t fn);
+
+/** Free a dispatch_cfg_t. */
+#define dcfg_free(cfg) \
+  FREE_AND_NULL(dispatch_cfg_t, dcfg_free_, (cfg))
+
+void dcfg_free_(dispatch_cfg_t *cfg);
+
+#endif /* !defined(TOR_DISPATCH_CFG_H) */
diff --git a/src/lib/dispatch/dispatch_cfg_st.h b/src/lib/dispatch/dispatch_cfg_st.h
new file mode 100644
index 000000000..57b6f0347
--- /dev/null
+++ b/src/lib/dispatch/dispatch_cfg_st.h
@@ -0,0 +1,25 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_DISPATCH_CFG_ST_H
+#define TOR_DISPATCH_CFG_ST_H
+
+struct smartlist_t;
+
+/* Information needed to create a dispatcher, but in a less efficient, more
+ * mutable format. */
+struct dispatch_cfg_t {
+  /** A list of msg_type_id_t (cast to void*), indexed by msg_t. */
+  struct smartlist_t *type_by_msg;
+  /** A list of channel_id_t (cast to void*), indexed by msg_t. */
+  struct smartlist_t *chan_by_msg;
+  /** A list of dispatch_rcv_t, indexed by msg_type_id_t. */
+  struct smartlist_t *fns_by_type;
+  /** A list of dispatch_typefns_t, indexed by msg_t. */
+  struct smartlist_t *recv_by_msg;
+};
+
+#endif /* !defined(TOR_DISPATCH_CFG_ST_H) */
diff --git a/src/lib/dispatch/dispatch_core.c b/src/lib/dispatch/dispatch_core.c
new file mode 100644
index 000000000..da54f9b43
--- /dev/null
+++ b/src/lib/dispatch/dispatch_core.c
@@ -0,0 +1,260 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file dispatch_core.c
+ * \brief Core module for sending and receiving messages.
+ */
+
+#define DISPATCH_PRIVATE
+#include "orconfig.h"
+
+#include "lib/dispatch/dispatch.h"
+#include "lib/dispatch/dispatch_st.h"
+#include "lib/dispatch/dispatch_naming.h"
+
+#include "lib/malloc/malloc.h"
+#include "lib/log/util_bug.h"
+
+#include <string.h>
+
+/**
+ * Use <b>d</b> to drop all storage held for <b>msg</b>.
+ *
+ * (We need the dispatcher so we know how to free the auxiliary data.)
+ **/
+void
+dispatch_free_msg_(const dispatch_t *d, msg_t *msg)
+{
+  if (!msg)
+    return;
+
+  d->typefns[msg->type].free_fn(msg->aux_data__);
+  tor_free(msg);
+}
+
+/**
+ * Format the auxiliary data held by msg.
+ **/
+char *
+dispatch_fmt_msg_data(const dispatch_t *d, const msg_t *msg)
+{
+  if (!msg)
+    return NULL;
+
+  return d->typefns[msg->type].fmt_fn(msg->aux_data__);
+}
+
+/**
+ * Release all storage held by <b>d</b>.
+ **/
+void
+dispatch_free_(dispatch_t *d)
+{
+  if (d == NULL)
+    return;
+
+  size_t n_queues = d->n_queues;
+  for (size_t i = 0; i < n_queues; ++i) {
+    msg_t *m, *mtmp;
+    TOR_SIMPLEQ_FOREACH_SAFE(m, &d->queues[i].queue, next, mtmp) {
+      dispatch_free_msg(d, m);
+    }
+  }
+
+  size_t n_msgs = d->n_msgs;
+
+  for (size_t i = 0; i < n_msgs; ++i) {
+    tor_free(d->table[i]);
+  }
+  tor_free(d->table);
+  tor_free(d->typefns);
+  tor_free(d->queues);
+
+  // This is the only time we will treat d->cfg as non-const.
+  //dispatch_cfg_free_((dispatch_items_t *) d->cfg);
+
+  tor_free(d);
+}
+
+/**
+ * Tell the dispatcher to call <b>fn</b> with <b>userdata</b> whenever
+ * <b>chan</b> becomes nonempty.  Return 0 on success, -1 on error.
+ **/
+int
+dispatch_set_alert_fn(dispatch_t *d, channel_id_t chan,
+                      dispatch_alertfn_t fn, void *userdata)
+{
+  if (BUG(chan >= d->n_queues))
+    return -1;
+
+  dqueue_t *q = &d->queues[chan];
+  q->alert_fn = fn;
+  q->alert_fn_arg = userdata;
+  return 0;
+}
+
+/**
+ * Send a message on the appropriate channel notifying that channel if
+ * necessary.
+ *
+ * This function takes ownership of the auxiliary data; it can't be static or
+ * stack-allocated, and the caller is not allowed to use it afterwards.
+ *
+ * This function does not check the various vields of the message object for
+ * consistency.
+ **/
+int
+dispatch_send(dispatch_t *d,
+              subsys_id_t sender,
+              channel_id_t channel,
+              message_id_t msg,
+              msg_type_id_t type,
+              msg_aux_data_t auxdata)
+{
+  if (!d->table[msg]) {
+    /* Fast path: nobody wants this data. */
+
+    d->typefns[type].free_fn(auxdata);
+    return 0;
+  }
+
+  msg_t *m = tor_malloc(sizeof(msg_t));
+
+  m->sender = sender;
+  m->channel = channel;
+  m->msg = msg;
+  m->type = type;
+  memcpy(&m->aux_data__, &auxdata, sizeof(msg_aux_data_t));
+
+  return dispatch_send_msg(d, m);
+}
+
+int
+dispatch_send_msg(dispatch_t *d, msg_t *m)
+{
+  if (BUG(!d))
+    goto err;
+  if (BUG(!m))
+    goto err;
+  if (BUG(m->channel >= d->n_queues))
+    goto err;
+  if (BUG(m->msg >= d->n_msgs))
+    goto err;
+
+  dtbl_entry_t *ent = d->table[m->msg];
+  if (ent) {
+    if (BUG(m->type != ent->type))
+      goto err;
+    if (BUG(m->channel != ent->channel))
+      goto err;
+  }
+
+  return dispatch_send_msg_unchecked(d, m);
+ err:
+  /* Probably it isn't safe to free m, since type could be wrong. */
+  return -1;
+}
+
+/**
+ * Send a message on the appropriate queue, notifying that queue if necessary.
+ *
+ * This function takes ownership of the message object and its auxiliary data;
+ * it can't be static or stack-allocated, and the caller isn't allowed to use
+ * it afterwards.
+ *
+ * This function does not check the various fields of the message object for
+ * consistency, and can crash if they are out of range.  Only functions that
+ * have already constructed the message in a safe way, or checked it for
+ * correctness themselves, should call this function.
+ **/
+int
+dispatch_send_msg_unchecked(dispatch_t *d, msg_t *m)
+{
+  /* Find the right queue. */
+  dqueue_t *q = &d->queues[m->channel];
+  bool was_empty = TOR_SIMPLEQ_EMPTY(&q->queue);
+
+  /* Append the message. */
+  TOR_SIMPLEQ_INSERT_TAIL(&q->queue, m, next);
+
+  if (debug_logging_enabled()) {
+    char *arg = dispatch_fmt_msg_data(d, m);
+    log_debug(LD_MESG,
+              "Queued: %s (%s) from %s, on %s.",
+              get_message_id_name(m->msg),
+              arg,
+              get_subsys_id_name(m->sender),
+              get_channel_id_name(m->channel));
+    tor_free(arg);
+  }
+
+  /* If we just made the queue nonempty for the first time, call the alert
+   * function. */
+  if (was_empty) {
+    q->alert_fn(d, m->channel, q->alert_fn_arg);
+  }
+
+  return 0;
+}
+
+/**
+ * Run all of the callbacks on <b>d</b> associated with <b>m</b>.
+ **/
+static void
+dispatcher_run_msg_cbs(const dispatch_t *d, msg_t *m)
+{
+  tor_assert(m->msg <= d->n_msgs);
+  dtbl_entry_t *ent = d->table[m->msg];
+  int n_fns = ent->n_fns;
+
+  if (debug_logging_enabled()) {
+    char *arg = dispatch_fmt_msg_data(d, m);
+    log_debug(LD_MESG,
+              "Delivering: %s (%s) from %s, on %s:",
+              get_message_id_name(m->msg),
+              arg,
+              get_subsys_id_name(m->sender),
+              get_channel_id_name(m->channel));
+    tor_free(arg);
+  }
+
+  int i;
+  for (i=0; i < n_fns; ++i) {
+    if (ent->rcv[i].enabled) {
+      log_debug(LD_MESG, "  Delivering to %s.",
+                get_subsys_id_name(ent->rcv[i].sys));
+      ent->rcv[i].fn(m);
+    }
+  }
+}
+
+/**
+ * Run up to <b>max_msgs</b> callbacks for messages on the channel <b>ch</b>
+ * on the given dispatcher.  Return 0 on success or recoverable failure,
+ * -1 on unrecoverable error.
+ **/
+int
+dispatch_flush(dispatch_t *d, channel_id_t ch, int max_msgs)
+{
+  if (BUG(ch >= d->n_queues))
+    return 0;
+
+  int n_flushed = 0;
+  dqueue_t *q = &d->queues[ch];
+
+  while (n_flushed < max_msgs) {
+    msg_t *m = TOR_SIMPLEQ_FIRST(&q->queue);
+    if (!m)
+      break;
+    TOR_SIMPLEQ_REMOVE_HEAD(&q->queue, next);
+    dispatcher_run_msg_cbs(d, m);
+    dispatch_free_msg(d, m);
+    ++n_flushed;
+  }
+
+  return 0;
+}
diff --git a/src/lib/dispatch/dispatch_naming.c b/src/lib/dispatch/dispatch_naming.c
new file mode 100644
index 000000000..83d9a2d60
--- /dev/null
+++ b/src/lib/dispatch/dispatch_naming.c
@@ -0,0 +1,63 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "orconfig.h"
+
+#include "lib/cc/compat_compiler.h"
+
+#include "lib/dispatch/dispatch_naming.h"
+#include "lib/dispatch/msgtypes.h"
+
+#include "lib/container/namemap.h"
+#include "lib/container/namemap_st.h"
+
+#include "lib/log/util_bug.h"
+#include "lib/log/log.h"
+
+#include <stdlib.h>
+
+/** Global namemap for message IDs. */
+static namemap_t message_id_map = NAMEMAP_INIT();
+/** Global namemap for subsystem IDs. */
+static namemap_t subsys_id_map = NAMEMAP_INIT();
+/** Global namemap for channel IDs. */
+static namemap_t channel_id_map = NAMEMAP_INIT();
+/** Global namemap for message type IDs. */
+static namemap_t msg_type_id_map = NAMEMAP_INIT();
+
+void
+dispatch_naming_init(void)
+{
+}
+
+/* Helper macro: declare functions to map IDs to and from names for a given
+ * type in a namemap_t.
+ */
+#define DECLARE_ID_MAP_FNS(type)                                        \
+  type##_id_t                                                           \
+  get_##type##_id(const char *name)                                     \
+  {                                                                     \
+    unsigned u = namemap_get_or_create_id(&type##_id_map, name);        \
+    tor_assert(u != NAMEMAP_ERR);                                       \
+    tor_assert(u != ERROR_ID);                                          \
+    return (type##_id_t) u;                                             \
+  }                                                                     \
+  const char *                                                          \
+  get_##type##_id_name(type##_id_t id)                                  \
+  {                                                                     \
+    return namemap_fmt_name(&type##_id_map, id);                        \
+  }                                                                     \
+  size_t                                                                \
+  get_num_##type##_ids(void)                                            \
+  {                                                                     \
+    return namemap_get_size(&type##_id_map);                            \
+  }                                                                     \
+  EAT_SEMICOLON
+
+DECLARE_ID_MAP_FNS(message);
+DECLARE_ID_MAP_FNS(channel);
+DECLARE_ID_MAP_FNS(subsys);
+DECLARE_ID_MAP_FNS(msg_type);
diff --git a/src/lib/dispatch/dispatch_naming.h b/src/lib/dispatch/dispatch_naming.h
new file mode 100644
index 000000000..fd6c83cc1
--- /dev/null
+++ b/src/lib/dispatch/dispatch_naming.h
@@ -0,0 +1,46 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_DISPATCH_NAMING_H
+#define TOR_DISPATCH_NAMING_H
+
+#include "lib/dispatch/msgtypes.h"
+#include <stddef.h>
+
+/**
+ * Return an existing channel ID by name, allocating the channel ID if
+ * if necessary.  Returns ERROR_ID if we have run out of
+ * channels
+ */
+channel_id_t get_channel_id(const char *);
+/**
+ * Return the name corresponding to a given channel ID.
+ **/
+const char *get_channel_id_name(channel_id_t);
+/**
+ * Return the total number of _named_ channel IDs.
+ **/
+size_t get_num_channel_ids(void);
+
+/* As above, but for messages. */
+message_id_t get_message_id(const char *);
+const char *get_message_id_name(message_id_t);
+size_t get_num_message_ids(void);
+
+/* As above, but for subsystems */
+subsys_id_t get_subsys_id(const char *);
+const char *get_subsys_id_name(subsys_id_t);
+size_t get_num_subsys_ids(void);
+
+/* As above, but for types. Note that types additionally must be
+ * "defined", if any message is to use them. */
+msg_type_id_t get_msg_type_id(const char *);
+const char *get_msg_type_id_name(msg_type_id_t);
+size_t get_num_msg_type_ids(void);
+
+void dispatch_naming_init(void);
+
+#endif /* !defined(TOR_DISPATCH_NAMING_H) */
diff --git a/src/lib/dispatch/dispatch_new.c b/src/lib/dispatch/dispatch_new.c
new file mode 100644
index 000000000..b89ef43ea
--- /dev/null
+++ b/src/lib/dispatch/dispatch_new.c
@@ -0,0 +1,174 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file dispatch_new.c
+ * \brief Code to construct a dispatch_t from a dispatch_cfg_t.
+ **/
+
+#define DISPATCH_PRIVATE
+#include "orconfig.h"
+
+#include "lib/dispatch/dispatch.h"
+#include "lib/dispatch/dispatch_st.h"
+#include "lib/dispatch/dispatch_cfg.h"
+#include "lib/dispatch/dispatch_cfg_st.h"
+
+#include "lib/cc/ctassert.h"
+#include "lib/intmath/cmp.h"
+#include "lib/malloc/malloc.h"
+#include "lib/log/util_bug.h"
+
+#include <string.h>
+
+/** Given a smartlist full of (possibly NULL) pointers to uint16_t values,
+ * return the largest value, or dflt if the list is empty. */
+static int
+max_in_sl(const smartlist_t *sl, int dflt)
+{
+  uint16_t *maxptr = NULL;
+  SMARTLIST_FOREACH_BEGIN(sl, uint16_t *, u) {
+    if (!maxptr)
+      maxptr = u;
+    else if (*u > *maxptr)
+      maxptr = u;
+  } SMARTLIST_FOREACH_END(u);
+
+  return maxptr ? *maxptr : dflt;
+}
+
+/* The above function is only safe to call if we are sure that channel_id_t
+ * and msg_type_id_t are really uint16_t.  They should be so defined in
+ * msgtypes.h, but let's be extra cautious.
+ */
+CTASSERT(sizeof(uint16_t) == sizeof(msg_type_id_t));
+CTASSERT(sizeof(uint16_t) == sizeof(channel_id_t));
+
+/** Helper: Format an unformattable message auxiliary data item: just return a
+* copy of the string <>. */
+static char *
+type_fmt_nop(msg_aux_data_t arg)
+{
+  (void)arg;
+  return tor_strdup("<>");
+}
+
+/** Helper: Free an unfreeable message auxiliary data item: do nothing. */
+static void
+type_free_nop(msg_aux_data_t arg)
+{
+  (void)arg;
+}
+
+/** Type functions to use when no type functions are provided. */
+static dispatch_typefns_t nop_typefns = {
+  .free_fn = type_free_nop,
+  .fmt_fn = type_fmt_nop
+};
+
+/**
+ * Alert function to use when none is configured: do nothing.
+ **/
+static void
+alert_fn_nop(dispatch_t *d, channel_id_t ch, void *arg)
+{
+  (void)d;
+  (void)ch;
+  (void)arg;
+}
+
+/**
+ * Given a list of recvfn_t, create and return a new dtbl_entry_t mapping
+ * to each of those functions.
+ **/
+static dtbl_entry_t *
+dtbl_entry_from_lst(smartlist_t *receivers)
+{
+  if (!receivers)
+    return NULL;
+
+  size_t n_recv = smartlist_len(receivers);
+  dtbl_entry_t *ent;
+  ent = tor_malloc_zero(offsetof(dtbl_entry_t, rcv) +
+                        sizeof(dispatch_rcv_t) * n_recv);
+
+  ent->n_fns = n_recv;
+
+  SMARTLIST_FOREACH_BEGIN(receivers, const dispatch_rcv_t *, rcv) {
+    memcpy(&ent->rcv[rcv_sl_idx], rcv, sizeof(*rcv));
+    if (rcv->enabled) {
+      ++ent->n_enabled;
+    }
+  } SMARTLIST_FOREACH_END(rcv);
+
+  return ent;
+}
+
+/** Create and return a new dispatcher from a given dispatch_cfg_t. */
+dispatch_t *
+dispatch_new(const dispatch_cfg_t *cfg)
+{
+  dispatch_t *d = tor_malloc_zero(sizeof(dispatch_t));
+
+  /* Any message that has a type or a receiver counts towards our messages */
+  const size_t n_msgs = MAX(smartlist_len(cfg->type_by_msg),
+                            smartlist_len(cfg->recv_by_msg)) + 1;
+
+  /* Any channel that any message has counts towards the number of channels. */
+  const size_t n_chans = (size_t) MAX(1, max_in_sl(cfg->chan_by_msg,0)) + 1;
+
+  /* Any type that a message has, or that has functions, counts towards
+   * the number of types. */
+  const size_t n_types = (size_t) MAX(max_in_sl(cfg->type_by_msg,0),
+                                      smartlist_len(cfg->fns_by_type)) + 1;
+
+  d->n_msgs = n_msgs;
+  d->n_queues = n_chans;
+  d->n_types = n_types;
+
+  /* Initialize the array of type-functions. */
+  d->typefns = tor_calloc(n_types, sizeof(dispatch_typefns_t));
+  for (size_t i = 0; i < n_types; ++i) {
+    /* Default to no-op for everything... */
+    memcpy(&d->typefns[i], &nop_typefns, sizeof(dispatch_typefns_t));
+  }
+  SMARTLIST_FOREACH_BEGIN(cfg->fns_by_type, dispatch_typefns_t *, fns) {
+    /* Set the functions if they are provided. */
+    if (fns) {
+      if (fns->free_fn)
+        d->typefns[fns_sl_idx].free_fn = fns->free_fn;
+      if (fns->fmt_fn)
+        d->typefns[fns_sl_idx].fmt_fn = fns->fmt_fn;
+    }
+  } SMARTLIST_FOREACH_END(fns);
+
+  /* Initialize the message queues: one for each channel. */
+  d->queues = tor_calloc(d->n_queues, sizeof(dqueue_t));
+  for (size_t i = 0; i < d->n_queues; ++i) {
+    TOR_SIMPLEQ_INIT(&d->queues[i].queue);
+    d->queues[i].alert_fn = alert_fn_nop;
+  }
+
+  /* Build the dispatch tables mapping message IDs to receivers. */
+  d->table = tor_calloc(d->n_msgs, sizeof(dtbl_entry_t *));
+  SMARTLIST_FOREACH_BEGIN(cfg->recv_by_msg, smartlist_t *, rcv) {
+    d->table[rcv_sl_idx] = dtbl_entry_from_lst(rcv);
+  } SMARTLIST_FOREACH_END(rcv);
+
+  /* Fill in the empty entries in the dispatch tables:
+   * types and channels for each message. */
+  SMARTLIST_FOREACH_BEGIN(cfg->type_by_msg, msg_type_id_t *, type) {
+    if (d->table[type_sl_idx])
+      d->table[type_sl_idx]->type = *type;
+  } SMARTLIST_FOREACH_END(type);
+
+  SMARTLIST_FOREACH_BEGIN(cfg->chan_by_msg, channel_id_t *, chan) {
+    if (d->table[chan_sl_idx])
+      d->table[chan_sl_idx]->channel = *chan;
+  } SMARTLIST_FOREACH_END(chan);
+
+  return d;
+}
diff --git a/src/lib/dispatch/dispatch_st.h b/src/lib/dispatch/dispatch_st.h
new file mode 100644
index 000000000..ee42518b5
--- /dev/null
+++ b/src/lib/dispatch/dispatch_st.h
@@ -0,0 +1,108 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file dispatch_st.h
+ *
+ * \brief private structures used for the dispatcher module
+ */
+
+#ifndef TOR_DISPATCH_ST_H
+#define TOR_DISPATCH_ST_H
+
+#ifdef DISPATCH_PRIVATE
+
+#include "lib/container/smartlist.h"
+
+/**
+ * Information about the recipient of a message.
+ **/
+typedef struct dispatch_rcv_t {
+  /** The subsystem receiving a message. */
+  subsys_id_t sys;
+  /** True iff this recipient is enabled. */
+  bool enabled;
+  /** The function that will handle the message. */
+  recv_fn_t fn;
+} dispatch_rcv_t;
+
+/**
+ * Information used by a dispatcher to handle and dispatch a single message
+ * ID.  It maps that message ID to its type, channel, and list of receiver
+ * functions.
+ *
+ * This structure is used when the dispatcher is running.
+ **/
+typedef struct dtbl_entry_t {
+  /** The number of enabled non-stub subscribers for this message.
+   *
+   * Note that for now, this will be the same as <b>n_fns</b>, since there is
+   * no way to turn these subscribers on an off yet. */
+  uint16_t n_enabled;
+  /** The channel that handles this message. */
+  channel_id_t channel;
+  /** The associated C type for this message. */
+  msg_type_id_t type;
+  /**
+   * The number of functions pointers for subscribers that receive this
+   * message, in rcv. */
+  uint16_t n_fns;
+  /**
+   * The recipients for this message.
+   */
+  dispatch_rcv_t rcv[FLEXIBLE_ARRAY_MEMBER];
+} dtbl_entry_t;
+
+/**
+ * A queue of messages for a given channel, used by a live dispatcher.
+ */
+typedef struct dqueue_t {
+  /** The queue of messages itself. */
+  TOR_SIMPLEQ_HEAD( , msg_t) queue;
+  /** A function to be called when the queue becomes nonempty. */
+  dispatch_alertfn_t alert_fn;
+  /** An argument for the alert_fn. */
+  void *alert_fn_arg;
+} dqueue_t ;
+
+/**
+ * A single dispatcher for cross-module messages.
+ */
+struct dispatch_t {
+  /**
+   * The length of <b>table</b>: the number of message IDs that this
+   * dispatcher can handle.
+   */
+  size_t n_msgs;
+  /**
+   * The length of <b>queues</b>: the number of channels that this dispatcher
+   * has configured.
+   */
+  size_t n_queues;
+  /**
+   * The length of <b>typefns</b>: the number of C type IDs that this
+   * dispatcher has configured.
+   */
+  size_t n_types;
+  /**
+   * An array of message queues, indexed by channel ID.
+   */
+  dqueue_t *queues;
+  /**
+   * An array of entries about how to handle particular message types, indexed
+   * by message ID.
+   */
+  dtbl_entry_t **table;
+  /**
+   * An array of function tables for manipulating types, index by message
+   * type ID.
+   **/
+  dispatch_typefns_t *typefns;
+};
+
+#endif /* defined(DISPATCH_PRIVATE) */
+
+#endif /* !defined(TOR_DISPATCH_ST_H) */
diff --git a/src/lib/dispatch/include.am b/src/lib/dispatch/include.am
new file mode 100644
index 000000000..4a0e0dfd9
--- /dev/null
+++ b/src/lib/dispatch/include.am
@@ -0,0 +1,27 @@
+
+noinst_LIBRARIES += src/lib/libtor-dispatch.a
+
+if UNITTESTS_ENABLED
+noinst_LIBRARIES += src/lib/libtor-dispatch-testing.a
+endif
+
+# ADD_C_FILE: INSERT SOURCES HERE.
+src_lib_libtor_dispatch_a_SOURCES =			\
+	src/lib/dispatch/dispatch_cfg.c			\
+	src/lib/dispatch/dispatch_core.c		\
+	src/lib/dispatch/dispatch_naming.c		\
+	src/lib/dispatch/dispatch_new.c
+
+src_lib_libtor_dispatch_testing_a_SOURCES = \
+	$(src_lib_libtor_dispatch_a_SOURCES)
+src_lib_libtor_dispatch_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
+src_lib_libtor_dispatch_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+
+# ADD_C_FILE: INSERT HEADERS HERE.
+noinst_HEADERS +=					\
+	src/lib/dispatch/dispatch.h			\
+	src/lib/dispatch/dispatch_cfg.h 		\
+	src/lib/dispatch/dispatch_cfg_st.h 		\
+	src/lib/dispatch/dispatch_naming.h		\
+	src/lib/dispatch/dispatch_st.h			\
+	src/lib/dispatch/msgtypes.h
diff --git a/src/lib/dispatch/msgtypes.h b/src/lib/dispatch/msgtypes.h
new file mode 100644
index 000000000..b4c4a1024
--- /dev/null
+++ b/src/lib/dispatch/msgtypes.h
@@ -0,0 +1,80 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file msgtypes.h
+ * \brief Types used for messages in the dispatcher code.
+ **/
+
+#ifndef TOR_DISPATCH_MSGTYPES_H
+#define TOR_DISPATCH_MSGTYPES_H
+
+#include <stdint.h>
+
+#include "ext/tor_queue.h"
+
+/**
+ * These types are aliases for subsystems, channels, and message IDs.
+ **/
+typedef uint16_t subsys_id_t;
+typedef uint16_t channel_id_t;
+typedef uint16_t message_id_t;
+
+/**
+ * This identifies a C type that can be sent along with a message.
+ **/
+typedef uint16_t msg_type_id_t;
+
+/**
+ * An ID value returned for *_type_t when none exists.
+ */
+#define ERROR_ID 65535
+
+/**
+ * Auxiliary (untyped) data sent along with a message.
+ *
+ * We define this as a union of a pointer and a u64, so that the integer
+ * types will have the same range across platforms.
+ **/
+typedef union {
+  void *ptr;
+  uint64_t u64;
+} msg_aux_data_t;
+
+/**
+ * Structure of a received message.
+ **/
+typedef struct msg_t {
+  TOR_SIMPLEQ_ENTRY(msg_t) next;
+  subsys_id_t sender;
+  channel_id_t channel;
+  message_id_t msg;
+  /** We could omit this field, since it is implicit in the message type, but
+   * IMO let's leave it in for safety. */
+  msg_type_id_t type;
+  /** Untyped auxiliary data. You shouldn't have to mess with this
+   * directly. */
+  msg_aux_data_t aux_data__;
+} msg_t;
+
+/**
+ * A function that a subscriber uses to receive a message.
+ **/
+typedef void (*recv_fn_t)(const msg_t *m);
+
+/**
+ * Table of functions to use for a given C type.  Any omitted (NULL) functions
+ * will be treated as no-ops.
+ **/
+typedef struct dispatch_typefns_t {
+  /** Release storage held for the auxiliary data of this type. */
+  void (*free_fn)(msg_aux_data_t);
+  /** Format and return a newly allocated string describing the contents
+   * of this data element. */
+  char *(*fmt_fn)(msg_aux_data_t);
+} dispatch_typefns_t;
+
+#endif /* !defined(TOR_DISPATCH_MSGTYPES_H) */
diff --git a/src/lib/encoding/binascii.c b/src/lib/encoding/binascii.c
index de4d1648b..fc64e014e 100644
--- a/src/lib/encoding/binascii.c
+++ b/src/lib/encoding/binascii.c
@@ -84,7 +84,7 @@ base32_encode(char *dest, size_t destlen, const char *src, size_t srclen)
 }
 
 /** Implements base32 decoding as in RFC 4648.
- * Returns 0 if successful, -1 otherwise.
+ * Return the number of bytes decoded if successful; -1 otherwise.
  */
 int
 base32_decode(char *dest, size_t destlen, const char *src, size_t srclen)
@@ -147,7 +147,7 @@ base32_decode(char *dest, size_t destlen, const char *src, size_t srclen)
   memset(tmp, 0, srclen); /* on the heap, this should be safe */
   tor_free(tmp);
   tmp = NULL;
-  return 0;
+  return i;
 }
 
 #define BASE64_OPENSSL_LINELEN 64
@@ -321,8 +321,10 @@ base64_encode(char *dest, size_t destlen, const char *src, size_t srclen,
   return (int) enclen;
 }
 
-/** As base64_encode, but do not add any internal spaces or external padding
- * to the output stream. */
+/** As base64_encode, but do not add any internal spaces, and remove external
+ * padding from the output stream.
+ * dest must be at least base64_encode_size(srclen, 0), including space for
+ * the removed external padding. */
 int
 base64_encode_nopad(char *dest, size_t destlen,
                     const uint8_t *src, size_t srclen)
diff --git a/src/lib/encoding/binascii.h b/src/lib/encoding/binascii.h
index 44998bb85..40c5593b1 100644
--- a/src/lib/encoding/binascii.h
+++ b/src/lib/encoding/binascii.h
@@ -58,4 +58,4 @@ size_t base32_encoded_size(size_t srclen);
 void base16_encode(char *dest, size_t destlen, const char *src, size_t srclen);
 int base16_decode(char *dest, size_t destlen, const char *src, size_t srclen);
 
-#endif /* !defined(TOR_UTIL_FORMAT_H) */
+#endif /* !defined(TOR_BINASCII_H) */
diff --git a/src/lib/encoding/confline.c b/src/lib/encoding/confline.c
index 8110f3dd9..fdb575e03 100644
--- a/src/lib/encoding/confline.c
+++ b/src/lib/encoding/confline.c
@@ -82,6 +82,19 @@ config_line_find(const config_line_t *lines,
   return NULL;
 }
 
+/** As config_line_find(), but perform a case-insensitive comparison. */
+const config_line_t *
+config_line_find_case(const config_line_t *lines,
+                      const char *key)
+{
+  const config_line_t *cl;
+  for (cl = lines; cl; cl = cl->next) {
+    if (!strcasecmp(cl->key, key))
+      return cl;
+  }
+  return NULL;
+}
+
 /** Auxiliary function that does all the work of config_get_lines.
  * <b>recursion_level</b> is the count of how many nested %includes we have.
  * <b>opened_lst</b> will have a list of opened files if provided.
diff --git a/src/lib/encoding/confline.h b/src/lib/encoding/confline.h
index 3d9ae8a66..56ea36bf6 100644
--- a/src/lib/encoding/confline.h
+++ b/src/lib/encoding/confline.h
@@ -48,6 +48,8 @@ config_line_t *config_lines_dup_and_filter(const config_line_t *inp,
                                            const char *key);
 const config_line_t *config_line_find(const config_line_t *lines,
                                       const char *key);
+const config_line_t *config_line_find_case(const config_line_t *lines,
+                                           const char *key);
 int config_lines_eq(config_line_t *a, config_line_t *b);
 int config_count_key(const config_line_t *a, const char *key);
 void config_free_lines_(config_line_t *front);
diff --git a/src/lib/encoding/include.am b/src/lib/encoding/include.am
index 83e9211b6..48d0120bf 100644
--- a/src/lib/encoding/include.am
+++ b/src/lib/encoding/include.am
@@ -4,6 +4,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-encoding-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_encoding_a_SOURCES =			\
 	src/lib/encoding/binascii.c			\
 	src/lib/encoding/confline.c			\
@@ -11,6 +12,7 @@ src_lib_libtor_encoding_a_SOURCES =			\
 	src/lib/encoding/keyval.c			\
 	src/lib/encoding/kvline.c			\
 	src/lib/encoding/pem.c				\
+	src/lib/encoding/qstring.c			\
 	src/lib/encoding/time_fmt.c
 
 src_lib_libtor_encoding_testing_a_SOURCES = \
@@ -18,6 +20,7 @@ src_lib_libtor_encoding_testing_a_SOURCES = \
 src_lib_libtor_encoding_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_encoding_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/encoding/binascii.h			\
 	src/lib/encoding/confline.h			\
@@ -25,4 +28,5 @@ noinst_HEADERS +=					\
 	src/lib/encoding/keyval.h			\
 	src/lib/encoding/kvline.h			\
 	src/lib/encoding/pem.h				\
+	src/lib/encoding/qstring.h			\
 	src/lib/encoding/time_fmt.h
diff --git a/src/lib/encoding/keyval.h b/src/lib/encoding/keyval.h
index cd327b7a8..dcddfa339 100644
--- a/src/lib/encoding/keyval.h
+++ b/src/lib/encoding/keyval.h
@@ -14,4 +14,4 @@
 
 int string_is_key_value(int severity, const char *string);
 
-#endif
+#endif /* !defined(TOR_KEYVAL_H) */
diff --git a/src/lib/encoding/kvline.c b/src/lib/encoding/kvline.c
index 307adc3f1..d4a8f510b 100644
--- a/src/lib/encoding/kvline.c
+++ b/src/lib/encoding/kvline.c
@@ -16,6 +16,7 @@
 #include "lib/encoding/confline.h"
 #include "lib/encoding/cstring.h"
 #include "lib/encoding/kvline.h"
+#include "lib/encoding/qstring.h"
 #include "lib/malloc/malloc.h"
 #include "lib/string/compat_ctype.h"
 #include "lib/string/printf.h"
@@ -54,6 +55,15 @@ line_has_no_key(const config_line_t *line)
 }
 
 /**
+ * Return true iff the value in <b>line</b> is not set.
+ **/
+static bool
+line_has_no_val(const config_line_t *line)
+{
+  return line->value == NULL || strlen(line->value) == 0;
+}
+
+/**
  * Return true iff the all the lines in <b>line</b> can be encoded
  * using <b>flags</b>.
  **/
@@ -98,14 +108,25 @@ kvline_can_encode_lines(const config_line_t *line, unsigned flags)
  * If KV_OMIT_KEYS is set in <b>flags</b>, then pairs with empty keys are
  * allowed, and are encoded as 'Value'.  Otherwise, such pairs are not
  * allowed.
+ *
+ * If KV_OMIT_VALS is set in <b>flags</b>, then an empty value is
+ * encoded as 'Key', not as 'Key=' or 'Key=""'.  Mutually exclusive with
+ * KV_OMIT_KEYS.
+ *
+ * KV_QUOTED_QSTRING is not supported.
  */
 char *
 kvline_encode(const config_line_t *line,
               unsigned flags)
 {
+  tor_assert(! (flags & KV_QUOTED_QSTRING));
+
   if (!kvline_can_encode_lines(line, flags))
     return NULL;
 
+  tor_assert((flags & (KV_OMIT_KEYS|KV_OMIT_VALS)) !=
+             (KV_OMIT_KEYS|KV_OMIT_VALS));
+
   smartlist_t *elements = smartlist_new();
 
   for (; line; line = line->next) {
@@ -126,7 +147,10 @@ kvline_encode(const config_line_t *line,
       }
     }
 
-    if (esc) {
+    if ((flags & KV_OMIT_VALS) && line_has_no_val(line)) {
+      eq = "";
+      v = "";
+    } else if (esc) {
       tmp = esc_for_log(line->value);
       v = tmp;
     } else {
@@ -151,17 +175,30 @@ kvline_encode(const config_line_t *line,
  * allocated list of pairs on success, or NULL on failure.
  *
  * If KV_QUOTED is set in <b>flags</b>, then (double-)quoted values are
- * allowed. Otherwise, such values are not allowed.
+ * allowed and handled as C strings. Otherwise, such values are not allowed.
  *
  * If KV_OMIT_KEYS is set in <b>flags</b>, then values without keys are
  * allowed.  Otherwise, such values are not allowed.
+ *
+ * If KV_OMIT_VALS is set in <b>flags</b>, then keys without values are
+ * allowed.  Otherwise, such keys are not allowed.  Mutually exclusive with
+ * KV_OMIT_KEYS.
+ *
+ * If KV_QUOTED_QSTRING is set in <b>flags</b>, then double-quoted values
+ * are allowed and handled as QuotedStrings per qstring.c.  Do not add
+ * new users of this flag.
  */
 config_line_t *
 kvline_parse(const char *line, unsigned flags)
 {
+  tor_assert((flags & (KV_OMIT_KEYS|KV_OMIT_VALS)) !=
+             (KV_OMIT_KEYS|KV_OMIT_VALS));
+
   const char *cp = line, *cplast = NULL;
-  bool omit_keys = (flags & KV_OMIT_KEYS) != 0;
-  bool quoted = (flags & KV_QUOTED) != 0;
+  const bool omit_keys = (flags & KV_OMIT_KEYS) != 0;
+  const bool omit_vals = (flags & KV_OMIT_VALS) != 0;
+  const bool quoted = (flags & (KV_QUOTED|KV_QUOTED_QSTRING)) != 0;
+  const bool c_quoted = (flags & (KV_QUOTED)) != 0;
 
   config_line_t *result = NULL;
   config_line_t **next_line = &result;
@@ -171,27 +208,33 @@ kvline_parse(const char *line, unsigned flags)
 
   while (*cp) {
     key = val = NULL;
+    /* skip all spaces */
     {
       size_t idx = strspn(cp, " \t\r\v\n");
       cp += idx;
     }
     if (BUG(cp == cplast)) {
-      /* If we didn't parse anything, this code is broken. */
+      /* If we didn't parse anything since the last loop, this code is
+       * broken. */
       goto err; // LCOV_EXCL_LINE
     }
     cplast = cp;
     if (! *cp)
       break; /* End of string; we're done. */
 
-    /* Possible formats are K=V, K="V", V, and "V", depending on flags. */
+    /* Possible formats are K=V, K="V", K, V, and "V", depending on flags. */
 
-    /* Find the key. */
+    /* Find where the key ends */
     if (*cp != '\"') {
       size_t idx = strcspn(cp, " \t\r\v\n=");
 
       if (cp[idx] == '=') {
         key = tor_memdup_nulterm(cp, idx);
         cp += idx + 1;
+      } else if (omit_vals) {
+        key = tor_memdup_nulterm(cp, idx);
+        cp += idx;
+        goto commit;
       } else {
         if (!omit_keys)
           goto err;
@@ -203,7 +246,11 @@ kvline_parse(const char *line, unsigned flags)
       if (!quoted)
         goto err;
       size_t len=0;
-      cp = unescape_string(cp, &val, &len);
+      if (c_quoted) {
+        cp = unescape_string(cp, &val, &len);
+      } else {
+        cp = decode_qstring(cp, strlen(cp), &val, &len);
+      }
       if (cp == NULL || len != strlen(val)) {
         // The string contains a NUL or is badly coded.
         goto err;
@@ -214,6 +261,7 @@ kvline_parse(const char *line, unsigned flags)
       cp += idx;
     }
 
+  commit:
     if (key && strlen(key) == 0) {
       /* We don't allow empty keys. */
       goto err;
@@ -221,13 +269,15 @@ kvline_parse(const char *line, unsigned flags)
 
     *next_line = tor_malloc_zero(sizeof(config_line_t));
     (*next_line)->key = key ? key : tor_strdup("");
-    (*next_line)->value = val;
+    (*next_line)->value = val ? val : tor_strdup("");
     next_line = &(*next_line)->next;
     key = val = NULL;
   }
 
-  if (!kvline_can_encode_lines(result, flags)) {
-    goto err;
+  if (! (flags & KV_QUOTED_QSTRING)) {
+    if (!kvline_can_encode_lines(result, flags)) {
+      goto err;
+    }
   }
   return result;
 
diff --git a/src/lib/encoding/kvline.h b/src/lib/encoding/kvline.h
index 4eed30a22..dea2ce180 100644
--- a/src/lib/encoding/kvline.h
+++ b/src/lib/encoding/kvline.h
@@ -17,6 +17,8 @@ struct config_line_t;
 
 #define KV_QUOTED    (1u<<0)
 #define KV_OMIT_KEYS (1u<<1)
+#define KV_OMIT_VALS (1u<<2)
+#define KV_QUOTED_QSTRING (1u<<3)
 
 struct config_line_t *kvline_parse(const char *line, unsigned flags);
 char *kvline_encode(const struct config_line_t *line, unsigned flags);
diff --git a/src/lib/encoding/pem.h b/src/lib/encoding/pem.h
index 0bbb06a79..6b20350aa 100644
--- a/src/lib/encoding/pem.h
+++ b/src/lib/encoding/pem.h
@@ -23,4 +23,4 @@ int pem_encode(char *dest, size_t destlen, const uint8_t *src, size_t srclen,
 int pem_decode(uint8_t *dest, size_t destlen, const char *src, size_t srclen,
                const char *objtype);
 
-#endif
+#endif /* !defined(TOR_PEM_H) */
diff --git a/src/lib/encoding/qstring.c b/src/lib/encoding/qstring.c
new file mode 100644
index 000000000..a92d28c70
--- /dev/null
+++ b/src/lib/encoding/qstring.c
@@ -0,0 +1,90 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file qstring.c
+ * \brief Implement QuotedString parsing.
+ *
+ * Note that this is only used for controller authentication; do not
+ * create new users for this.  Instead, prefer the cstring.c functions.
+ **/
+
+#include "orconfig.h"
+#include "lib/encoding/qstring.h"
+#include "lib/malloc/malloc.h"
+#include "lib/log/util_bug.h"
+
+/** If the first <b>in_len_max</b> characters in <b>start</b> contain a
+ * QuotedString, return the length of that
+ * string (as encoded, including quotes).  Otherwise return -1. */
+static inline int
+get_qstring_length(const char *start, size_t in_len_max,
+                          int *chars_out)
+{
+  const char *cp, *end;
+  int chars = 0;
+
+  if (*start != '\"')
+    return -1;
+
+  cp = start+1;
+  end = start+in_len_max;
+
+  /* Calculate length. */
+  while (1) {
+    if (cp >= end) {
+      return -1; /* Too long. */
+    } else if (*cp == '\\') {
+      if (++cp == end)
+        return -1; /* Can't escape EOS. */
+      ++cp;
+      ++chars;
+    } else if (*cp == '\"') {
+      break;
+    } else {
+      ++cp;
+      ++chars;
+    }
+  }
+  if (chars_out)
+    *chars_out = chars;
+  return (int)(cp - start+1);
+}
+
+/** Given a pointer to a string starting at <b>start</b> containing
+ * <b>in_len_max</b> characters, decode a string beginning with one double
+ * quote, containing any number of non-quote characters or characters escaped
+ * with a backslash, and ending with a final double quote.  Place the resulting
+ * string (unquoted, unescaped) into a newly allocated string in *<b>out</b>;
+ * store its length in <b>out_len</b>.  On success, return a pointer to the
+ * character immediately following the escaped string.  On failure, return
+ * NULL. */
+const char *
+decode_qstring(const char *start, size_t in_len_max,
+               char **out, size_t *out_len)
+{
+  const char *cp, *end;
+  char *outp;
+  int len, n_chars = 0;
+
+  len = get_qstring_length(start, in_len_max, &n_chars);
+  if (len<0)
+    return NULL;
+
+  end = start+len-1; /* Index of last quote. */
+  tor_assert(*end == '\"');
+  outp = *out = tor_malloc(len+1);
+  *out_len = n_chars;
+
+  cp = start+1;
+  while (cp < end) {
+    if (*cp == '\\')
+      ++cp;
+    *outp++ = *cp++;
+  }
+  *outp = '\0';
+  tor_assert((outp - *out) == (int)*out_len);
+
+  return end+1;
+}
diff --git a/src/lib/encoding/qstring.h b/src/lib/encoding/qstring.h
new file mode 100644
index 000000000..840e1044c
--- /dev/null
+++ b/src/lib/encoding/qstring.h
@@ -0,0 +1,18 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file qstring.h
+ * \brief Header for qstring.c
+ */
+
+#ifndef TOR_ENCODING_QSTRING_H
+#define TOR_ENCODING_QSTRING_H
+
+#include <stddef.h>
+
+const char *decode_qstring(const char *start, size_t in_len_max,
+                           char **out, size_t *out_len);
+
+#endif /* !defined(TOR_ENCODING_QSTRING_H) */
diff --git a/src/lib/encoding/time_fmt.h b/src/lib/encoding/time_fmt.h
index 0ddeca57f..d14bc1f90 100644
--- a/src/lib/encoding/time_fmt.h
+++ b/src/lib/encoding/time_fmt.h
@@ -41,4 +41,4 @@ int parse_iso_time_nospace(const char *cp, time_t *t);
 int parse_http_time(const char *buf, struct tm *tm);
 int format_time_interval(char *out, size_t out_len, long interval);
 
-#endif
+#endif /* !defined(TOR_TIME_FMT_H) */
diff --git a/src/lib/err/.may_include b/src/lib/err/.may_include
index daa1b6e4c..314424545 100644
--- a/src/lib/err/.may_include
+++ b/src/lib/err/.may_include
@@ -1,5 +1,6 @@
 orconfig.h
 lib/cc/*.h
+lib/defs/*.h
 lib/err/*.h
 lib/subsys/*.h
-lib/version/*.h
\ No newline at end of file
+lib/version/*.h
diff --git a/src/lib/err/backtrace.c b/src/lib/err/backtrace.c
index 1d1b3bcfa..e6cbe3d32 100644
--- a/src/lib/err/backtrace.c
+++ b/src/lib/err/backtrace.c
@@ -115,7 +115,7 @@ clean_backtrace(void **stack, size_t depth, const ucontext_t *ctx)
  * that with a backtrace log.  Send messages via the tor_log function at
  * logger". */
 void
-log_backtrace_impl(int severity, int domain, const char *msg,
+log_backtrace_impl(int severity, log_domain_mask_t domain, const char *msg,
                    tor_log_fn logger)
 {
   size_t depth;
@@ -240,7 +240,7 @@ remove_bt_handler(void)
 
 #ifdef NO_BACKTRACE_IMPL
 void
-log_backtrace_impl(int severity, int domain, const char *msg,
+log_backtrace_impl(int severity, log_domain_mask_t domain, const char *msg,
                    tor_log_fn logger)
 {
   logger(severity, domain, "%s. (Stack trace not available)", msg);
diff --git a/src/lib/err/backtrace.h b/src/lib/err/backtrace.h
index 9b313261e..dcd22cfef 100644
--- a/src/lib/err/backtrace.h
+++ b/src/lib/err/backtrace.h
@@ -12,11 +12,14 @@
 
 #include "orconfig.h"
 #include "lib/cc/compat_compiler.h"
+#include "lib/cc/torint.h"
+#include "lib/defs/logging_types.h"
 
-typedef void (*tor_log_fn)(int, unsigned, const char *fmt, ...)
+typedef void (*tor_log_fn)(int, log_domain_mask_t, const char *fmt, ...)
   CHECK_PRINTF(3,4);
 
-void log_backtrace_impl(int severity, int domain, const char *msg,
+void log_backtrace_impl(int severity, log_domain_mask_t domain,
+                        const char *msg,
                         tor_log_fn logger);
 int configure_backtrace_handler(const char *tor_version);
 void clean_up_backtrace_handler(void);
diff --git a/src/lib/err/include.am b/src/lib/err/include.am
index 43adcd269..883ac9151 100644
--- a/src/lib/err/include.am
+++ b/src/lib/err/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-err-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_err_a_SOURCES =			\
 	src/lib/err/backtrace.c			\
 	src/lib/err/torerr.c			\
@@ -15,6 +16,7 @@ src_lib_libtor_err_testing_a_SOURCES = \
 src_lib_libtor_err_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_err_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/err/backtrace.h				\
 	src/lib/err/torerr.h				\
diff --git a/src/lib/err/torerr.h b/src/lib/err/torerr.h
index 0badaf7c6..c2da6697a 100644
--- a/src/lib/err/torerr.h
+++ b/src/lib/err/torerr.h
@@ -45,4 +45,4 @@ void tor_log_sigsafe_err_set_granularity(int ms);
 int format_hex_number_sigsafe(unsigned long x, char *buf, int max_len);
 int format_dec_number_sigsafe(unsigned long x, char *buf, int max_len);
 
-#endif /* !defined(TOR_TORLOG_H) */
+#endif /* !defined(TOR_TORERR_H) */
diff --git a/src/lib/evloop/include.am b/src/lib/evloop/include.am
index 6b0076272..6595b3a34 100644
--- a/src/lib/evloop/include.am
+++ b/src/lib/evloop/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-evloop-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_evloop_a_SOURCES =			\
 	src/lib/evloop/compat_libevent.c		\
 	src/lib/evloop/procmon.c			\
@@ -12,12 +13,12 @@ src_lib_libtor_evloop_a_SOURCES =			\
 	src/lib/evloop/token_bucket.c			\
 	src/lib/evloop/workqueue.c
 
-
 src_lib_libtor_evloop_testing_a_SOURCES = \
 	$(src_lib_libtor_evloop_a_SOURCES)
 src_lib_libtor_evloop_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_evloop_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/evloop/compat_libevent.h		\
 	src/lib/evloop/procmon.h			\
diff --git a/src/lib/evloop/token_bucket.h b/src/lib/evloop/token_bucket.h
index 9398d2baa..1ce6f1bf9 100644
--- a/src/lib/evloop/token_bucket.h
+++ b/src/lib/evloop/token_bucket.h
@@ -112,6 +112,6 @@ token_bucket_rw_get_write(const token_bucket_rw_t *bucket)
 
 STATIC uint32_t rate_per_sec_to_rate_per_step(uint32_t rate);
 
-#endif
+#endif /* defined(TOKEN_BUCKET_PRIVATE) */
 
-#endif /* TOR_TOKEN_BUCKET_H */
+#endif /* !defined(TOR_TOKEN_BUCKET_H) */
diff --git a/src/lib/evloop/workqueue.c b/src/lib/evloop/workqueue.c
index b36a02da5..015b69429 100644
--- a/src/lib/evloop/workqueue.c
+++ b/src/lib/evloop/workqueue.c
@@ -59,9 +59,6 @@ struct threadpool_s {
    * <b>p</b> is work[p]. */
   work_tailq_t work[WORKQUEUE_N_PRIORITIES];
 
-  /** Weak RNG, used to decide when to ignore priority. */
-  tor_weak_rng_t weak_rng;
-
   /** The current 'update generation' of the threadpool.  Any thread that is
    * at an earlier generation needs to run the update function. */
   unsigned generation;
@@ -238,7 +235,7 @@ worker_thread_extract_next_work(workerthread_t *thread)
     this_queue = &pool->work[i];
     if (!TOR_TAILQ_EMPTY(this_queue)) {
       queue = this_queue;
-      if (! tor_weak_random_one_in_n(&pool->weak_rng,
+      if (! crypto_fast_rng_one_in_n(get_thread_fast_rng(),
                                      thread->lower_priority_chance)) {
         /* Usually we'll just break now, so that we can get out of the loop
          * and use the queue where we found work. But with a small
@@ -555,11 +552,6 @@ threadpool_new(int n_threads,
   for (i = WORKQUEUE_PRIORITY_FIRST; i <= WORKQUEUE_PRIORITY_LAST; ++i) {
     TOR_TAILQ_INIT(&pool->work[i]);
   }
-  {
-    unsigned seed;
-    crypto_rand((void*)&seed, sizeof(seed));
-    tor_init_weak_random(&pool->weak_rng, seed);
-  }
 
   pool->new_thread_state_fn = new_thread_state_fn;
   pool->new_thread_state_arg = arg;
diff --git a/src/lib/fdio/include.am b/src/lib/fdio/include.am
index 6c18f00a0..545bbc929 100644
--- a/src/lib/fdio/include.am
+++ b/src/lib/fdio/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-fdio-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_fdio_a_SOURCES =			\
 	src/lib/fdio/fdio.c
 
@@ -13,5 +14,6 @@ src_lib_libtor_fdio_testing_a_SOURCES = \
 src_lib_libtor_fdio_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_fdio_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/fdio/fdio.h
diff --git a/src/lib/fs/conffile.h b/src/lib/fs/conffile.h
index 7af9119db..29115e108 100644
--- a/src/lib/fs/conffile.h
+++ b/src/lib/fs/conffile.h
@@ -20,4 +20,4 @@ int config_get_lines_include(const char *string, struct config_line_t **result,
                              int extended, int *has_include,
                              struct smartlist_t *opened_lst);
 
-#endif /* !defined(TOR_CONFLINE_H) */
+#endif /* !defined(TOR_CONFFILE_H) */
diff --git a/src/lib/fs/dir.h b/src/lib/fs/dir.h
index 826bc2dfc..9ff81faa4 100644
--- a/src/lib/fs/dir.h
+++ b/src/lib/fs/dir.h
@@ -30,4 +30,4 @@ MOCK_DECL(int, check_private_dir, (const char *dirname, cpd_check_t check,
 
 MOCK_DECL(struct smartlist_t *, tor_listdir, (const char *dirname));
 
-#endif
+#endif /* !defined(TOR_DIR_H) */
diff --git a/src/lib/fs/files.h b/src/lib/fs/files.h
index 52c94c914..81dba8c14 100644
--- a/src/lib/fs/files.h
+++ b/src/lib/fs/files.h
@@ -27,7 +27,7 @@
 #ifdef HAVE_SYS_STAT_H
 #include <sys/stat.h>
 #endif
-#endif
+#endif /* defined(_WIN32) */
 
 #ifndef O_BINARY
 #define O_BINARY 0
@@ -108,7 +108,7 @@ char *read_file_to_str_until_eof(int fd, size_t max_bytes_to_read,
  * Tor is built for unit tests, or when Tor is built on an operating system
  * without its own getdelim(). */
 ssize_t compat_getdelim_(char **lineptr, size_t *n, int delim, FILE *stream);
-#endif
+#endif /* !defined(HAVE_GETDELIM) || defined(TOR_UNIT_TESTS) */
 
 #ifdef HAVE_GETDELIM
 /**
@@ -123,10 +123,10 @@ ssize_t compat_getdelim_(char **lineptr, size_t *n, int delim, FILE *stream);
  */
 #define tor_getdelim(lineptr, n, delim, stream) \
   getdelim((lineptr), (n), (delim), (stream))
-#else
+#else /* !(defined(HAVE_GETDELIM)) */
 #define tor_getdelim(lineptr, n, delim, stream) \
   compat_getdelim_((lineptr), (n), (delim), (stream))
-#endif
+#endif /* defined(HAVE_GETDELIM) */
 
 #ifdef HAVE_GETLINE
 /**
@@ -137,9 +137,9 @@ ssize_t compat_getdelim_(char **lineptr, size_t *n, int delim, FILE *stream);
  */
 #define tor_getline(lineptr, n, stream) \
   getline((lineptr), (n), (stream))
-#else
+#else /* !(defined(HAVE_GETLINE)) */
 #define tor_getline(lineptr, n, stream) \
   tor_getdelim((lineptr), (n), '\n', (stream))
-#endif
+#endif /* defined(HAVE_GETLINE) */
 
-#endif
+#endif /* !defined(TOR_FS_H) */
diff --git a/src/lib/fs/include.am b/src/lib/fs/include.am
index f33e4d643..493db8f04 100644
--- a/src/lib/fs/include.am
+++ b/src/lib/fs/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-fs-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_fs_a_SOURCES =			\
 	src/lib/fs/conffile.c			\
 	src/lib/fs/dir.c			\
@@ -25,6 +26,7 @@ src_lib_libtor_fs_testing_a_SOURCES = \
 src_lib_libtor_fs_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_fs_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/fs/conffile.h				\
 	src/lib/fs/dir.h				\
diff --git a/src/lib/fs/lockfile.h b/src/lib/fs/lockfile.h
index 8aeee4cc7..fc0281e25 100644
--- a/src/lib/fs/lockfile.h
+++ b/src/lib/fs/lockfile.h
@@ -17,4 +17,4 @@ tor_lockfile_t *tor_lockfile_lock(const char *filename, int blocking,
                                   int *locked_out);
 void tor_lockfile_unlock(tor_lockfile_t *lockfile);
 
-#endif
+#endif /* !defined(TOR_LOCKFILE_H) */
diff --git a/src/lib/fs/mmap.c b/src/lib/fs/mmap.c
index daaee1f9b..f71c0cff7 100644
--- a/src/lib/fs/mmap.c
+++ b/src/lib/fs/mmap.c
@@ -237,4 +237,4 @@ tor_munmap_file(tor_mmap_t *handle)
 }
 #else
 #error "cannot implement tor_mmap_file"
-#endif /* defined(HAVE_MMAP) || ... || ... */
+#endif /* defined(HAVE_MMAP) || defined(RUNNING_DOXYGEN) || ... */
diff --git a/src/lib/fs/mmap.h b/src/lib/fs/mmap.h
index 18fb18a13..61aad544b 100644
--- a/src/lib/fs/mmap.h
+++ b/src/lib/fs/mmap.h
@@ -38,4 +38,4 @@ typedef struct tor_mmap_t {
 tor_mmap_t *tor_mmap_file(const char *filename);
 int tor_munmap_file(tor_mmap_t *handle);
 
-#endif
+#endif /* !defined(TOR_MMAP_H) */
diff --git a/src/lib/fs/path.h b/src/lib/fs/path.h
index 4675ac84e..28a1838b8 100644
--- a/src/lib/fs/path.h
+++ b/src/lib/fs/path.h
@@ -27,4 +27,4 @@ void clean_fname_for_stat(char *name);
 int get_parent_directory(char *fname);
 char *make_path_absolute(char *fname);
 
-#endif
+#endif /* !defined(TOR_PATH_H) */
diff --git a/src/lib/fs/userdb.h b/src/lib/fs/userdb.h
index 5c3979487..5e5ddb89a 100644
--- a/src/lib/fs/userdb.h
+++ b/src/lib/fs/userdb.h
@@ -21,6 +21,6 @@ struct passwd;
 const struct passwd *tor_getpwnam(const char *username);
 const struct passwd *tor_getpwuid(uid_t uid);
 char *get_user_homedir(const char *username);
-#endif
+#endif /* !defined(_WIN32) */
 
-#endif
+#endif /* !defined(TOR_USERDB_H) */
diff --git a/src/lib/fs/winlib.h b/src/lib/fs/winlib.h
index 64a22439e..7237226c7 100644
--- a/src/lib/fs/winlib.h
+++ b/src/lib/fs/winlib.h
@@ -17,6 +17,6 @@
 #include <tchar.h>
 
 HANDLE load_windows_system_library(const TCHAR *library_name);
-#endif
+#endif /* defined(_WIN32) */
 
-#endif
+#endif /* !defined(TOR_WINLIB_H) */
diff --git a/src/lib/geoip/country.h b/src/lib/geoip/country.h
index 9a8911d49..a24a1c4c0 100644
--- a/src/lib/geoip/country.h
+++ b/src/lib/geoip/country.h
@@ -13,4 +13,4 @@ typedef int16_t country_t;
 
 #define COUNTRY_MAX INT16_MAX
 
-#endif
+#endif /* !defined(TOR_COUNTRY_H) */
diff --git a/src/lib/geoip/include.am b/src/lib/geoip/include.am
index 9710d75ac..ea426d14b 100644
--- a/src/lib/geoip/include.am
+++ b/src/lib/geoip/include.am
@@ -4,6 +4,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-geoip-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_geoip_a_SOURCES =			\
 	src/lib/geoip/geoip.c
 
@@ -12,6 +13,7 @@ src_lib_libtor_geoip_testing_a_SOURCES = \
 src_lib_libtor_geoip_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_geoip_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/geoip/geoip.h   			\
 	src/lib/geoip/country.h
diff --git a/src/lib/intmath/addsub.h b/src/lib/intmath/addsub.h
index 83efa8291..3f745d457 100644
--- a/src/lib/intmath/addsub.h
+++ b/src/lib/intmath/addsub.h
@@ -16,4 +16,4 @@
 
 uint32_t tor_add_u32_nowrap(uint32_t a, uint32_t b);
 
-#endif /* !defined(TOR_INTMATH_MULDIV_H) */
+#endif /* !defined(TOR_INTMATH_ADDSUB_H) */
diff --git a/src/lib/intmath/include.am b/src/lib/intmath/include.am
index 45ee3bd53..155ffa145 100644
--- a/src/lib/intmath/include.am
+++ b/src/lib/intmath/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-intmath-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_intmath_a_SOURCES =			\
 	src/lib/intmath/addsub.c			\
 	src/lib/intmath/bits.c				\
@@ -16,6 +17,7 @@ src_lib_libtor_intmath_testing_a_SOURCES = \
 src_lib_libtor_intmath_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_intmath_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/intmath/addsub.h			\
 	src/lib/intmath/cmp.h				\
diff --git a/src/lib/intmath/logic.h b/src/lib/intmath/logic.h
index a4cecd69c..b2f77462e 100644
--- a/src/lib/intmath/logic.h
+++ b/src/lib/intmath/logic.h
@@ -17,4 +17,4 @@
 /** Macro: true if two values have different boolean values. */
 #define bool_neq(a,b) (!(a)!=!(b))
 
-#endif
+#endif /* !defined(HAVE_TOR_LOGIC_H) */
diff --git a/src/lib/intmath/weakrng.h b/src/lib/intmath/weakrng.h
index e26bf58cb..40941e59b 100644
--- a/src/lib/intmath/weakrng.h
+++ b/src/lib/intmath/weakrng.h
@@ -28,4 +28,4 @@ int32_t tor_weak_random_range(tor_weak_rng_t *rng, int32_t top);
  * <b>n</b> */
 #define tor_weak_random_one_in_n(rng, n) (0==tor_weak_random_range((rng),(n)))
 
-#endif
+#endif /* !defined(TOR_WEAKRNG_H) */
diff --git a/src/lib/lock/compat_mutex.h b/src/lib/lock/compat_mutex.h
index b63ce2402..e0c3d7cb7 100644
--- a/src/lib/lock/compat_mutex.h
+++ b/src/lib/lock/compat_mutex.h
@@ -48,7 +48,7 @@ typedef struct tor_mutex_t {
 #else
   /** No-threads only: Dummy variable so that tor_mutex_t takes up space. */
   int _unused;
-#endif /* defined(USE_WIN32_MUTEX) || ... */
+#endif /* defined(USE_WIN32_THREADS) || ... */
 } tor_mutex_t;
 
 tor_mutex_t *tor_mutex_new(void);
diff --git a/src/lib/lock/include.am b/src/lib/lock/include.am
index 4e6f44434..1475b9911 100644
--- a/src/lib/lock/include.am
+++ b/src/lib/lock/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-lock-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_lock_a_SOURCES =			\
 	src/lib/lock/compat_mutex.c
 
@@ -20,5 +21,6 @@ src_lib_libtor_lock_testing_a_SOURCES = \
 src_lib_libtor_lock_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_lock_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/lock/compat_mutex.h
diff --git a/src/lib/log/.may_include b/src/lib/log/.may_include
index 11c87f0a0..54d96324d 100644
--- a/src/lib/log/.may_include
+++ b/src/lib/log/.may_include
@@ -1,6 +1,7 @@
 orconfig.h
 
 lib/cc/*.h
+lib/defs/*.h
 lib/smartlist_core/*.h
 lib/err/*.h
 lib/fdio/*.h
diff --git a/src/lib/log/escape.h b/src/lib/log/escape.h
index 2f726186c..0b9fc3406 100644
--- a/src/lib/log/escape.h
+++ b/src/lib/log/escape.h
@@ -20,4 +20,4 @@ char *esc_for_log(const char *string) ATTR_MALLOC;
 char *esc_for_log_len(const char *chars, size_t n) ATTR_MALLOC;
 const char *escaped(const char *string);
 
-#endif /* !defined(TOR_TORLOG_H) */
+#endif /* !defined(TOR_ESCAPE_H) */
diff --git a/src/lib/log/include.am b/src/lib/log/include.am
index 9d3dbe310..5b9f7113b 100644
--- a/src/lib/log/include.am
+++ b/src/lib/log/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-log-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_log_a_SOURCES =			\
 	src/lib/log/escape.c			\
 	src/lib/log/ratelim.c			\
@@ -21,6 +22,7 @@ src_lib_libtor_log_testing_a_SOURCES = \
 src_lib_libtor_log_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_log_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/log/escape.h				\
 	src/lib/log/ratelim.h				\
diff --git a/src/lib/log/log.c b/src/lib/log/log.c
index d21d8d1d4..d95bf1ff6 100644
--- a/src/lib/log/log.c
+++ b/src/lib/log/log.c
@@ -49,6 +49,7 @@
 #include "lib/wallclock/approx_time.h"
 #include "lib/wallclock/time_to_tm.h"
 #include "lib/fdio/fdio.h"
+#include "lib/cc/ctassert.h"
 
 #ifdef HAVE_ANDROID_LOG_H
 #include <android/log.h>
@@ -154,7 +155,7 @@ severity_to_android_log_priority(int severity)
       // LCOV_EXCL_STOP
   }
 }
-#endif // HAVE_ANDROID_LOG_H.
+#endif /* defined(HAVE_ANDROID_LOG_H) */
 
 /** A mutex to guard changes to logfiles and logging. */
 static tor_mutex_t log_mutex;
@@ -1021,7 +1022,7 @@ flush_pending_log_callbacks(void)
   do {
     SMARTLIST_FOREACH_BEGIN(messages, pending_log_message_t *, msg) {
       const int severity = msg->severity;
-      const int domain = msg->domain;
+      const log_domain_mask_t domain = msg->domain;
       for (lf = logfiles; lf; lf = lf->next) {
         if (! lf->callback || lf->seems_dead ||
             ! (lf->severities->masks[SEVERITY_MASK_IDX(severity)] & domain)) {
@@ -1232,7 +1233,7 @@ add_android_log(const log_severity_list_t *severity,
   UNLOCK_LOGS();
   return 0;
 }
-#endif // HAVE_ANDROID_LOG_H.
+#endif /* defined(HAVE_ANDROID_LOG_H) */
 
 /** If <b>level</b> is a valid log severity, return the corresponding
  * numeric value.  Otherwise, return -1. */
@@ -1268,9 +1269,14 @@ static const char *domain_list[] = {
   "GENERAL", "CRYPTO", "NET", "CONFIG", "FS", "PROTOCOL", "MM",
   "HTTP", "APP", "CONTROL", "CIRC", "REND", "BUG", "DIR", "DIRSERV",
   "OR", "EDGE", "ACCT", "HIST", "HANDSHAKE", "HEARTBEAT", "CHANNEL",
-  "SCHED", "GUARD", "CONSDIFF", "DOS", "PROCESS", "PT", "BTRACK", NULL
+  "SCHED", "GUARD", "CONSDIFF", "DOS", "PROCESS", "PT", "BTRACK", "MESG",
+  NULL
 };
 
+CTASSERT(ARRAY_LENGTH(domain_list) == N_LOGGING_DOMAINS + 1);
+
+CTASSERT((UINT64_C(1)<<(N_LOGGING_DOMAINS-1)) < LOWEST_RESERVED_LD_FLAG_);
+
 /** Return a bitmask for the log domain for which <b>domain</b> is the name,
  * or 0 if there is no such name. */
 static log_domain_mask_t
@@ -1371,7 +1377,7 @@ parse_log_severity_config(const char **cfg_ptr,
             if (!strcmp(domain, "*")) {
               domains = ~0u;
             } else {
-              int d;
+              log_domain_mask_t d;
               int negate=0;
               if (*domain == '~') {
                 negate = 1;
diff --git a/src/lib/log/log.h b/src/lib/log/log.h
index dbc1c4702..c4a27782c 100644
--- a/src/lib/log/log.h
+++ b/src/lib/log/log.h
@@ -11,10 +11,12 @@
  **/
 
 #ifndef TOR_TORLOG_H
+#define TOR_TORLOG_H
 
 #include <stdarg.h>
 #include "lib/cc/torint.h"
 #include "lib/cc/compat_compiler.h"
+#include "lib/defs/logging_types.h"
 #include "lib/testsupport/testsupport.h"
 
 #ifdef HAVE_SYSLOG_H
@@ -55,81 +57,81 @@
 /* Logging domains */
 
 /** Catch-all for miscellaneous events and fatal errors. */
-#define LD_GENERAL  (1u<<0)
+#define LD_GENERAL  (UINT64_C(1)<<0)
 /** The cryptography subsystem. */
-#define LD_CRYPTO   (1u<<1)
+#define LD_CRYPTO   (UINT64_C(1)<<1)
 /** Networking. */
-#define LD_NET      (1u<<2)
+#define LD_NET      (UINT64_C(1)<<2)
 /** Parsing and acting on our configuration. */
-#define LD_CONFIG   (1u<<3)
+#define LD_CONFIG   (UINT64_C(1)<<3)
 /** Reading and writing from the filesystem. */
-#define LD_FS       (1u<<4)
+#define LD_FS       (UINT64_C(1)<<4)
 /** Other servers' (non)compliance with the Tor protocol. */
-#define LD_PROTOCOL (1u<<5)
+#define LD_PROTOCOL (UINT64_C(1)<<5)
 /** Memory management. */
-#define LD_MM       (1u<<6)
+#define LD_MM       (UINT64_C(1)<<6)
 /** HTTP implementation. */
-#define LD_HTTP     (1u<<7)
+#define LD_HTTP     (UINT64_C(1)<<7)
 /** Application (socks) requests. */
-#define LD_APP      (1u<<8)
+#define LD_APP      (UINT64_C(1)<<8)
 /** Communication via the controller protocol. */
-#define LD_CONTROL  (1u<<9)
+#define LD_CONTROL  (UINT64_C(1)<<9)
 /** Building, using, and managing circuits. */
-#define LD_CIRC     (1u<<10)
+#define LD_CIRC     (UINT64_C(1)<<10)
 /** Hidden services. */
-#define LD_REND     (1u<<11)
+#define LD_REND     (UINT64_C(1)<<11)
 /** Internal errors in this Tor process. */
-#define LD_BUG      (1u<<12)
+#define LD_BUG      (UINT64_C(1)<<12)
 /** Learning and using information about Tor servers. */
-#define LD_DIR      (1u<<13)
+#define LD_DIR      (UINT64_C(1)<<13)
 /** Learning and using information about Tor servers. */
-#define LD_DIRSERV  (1u<<14)
+#define LD_DIRSERV  (UINT64_C(1)<<14)
 /** Onion routing protocol. */
-#define LD_OR       (1u<<15)
+#define LD_OR       (UINT64_C(1)<<15)
 /** Generic edge-connection functionality. */
-#define LD_EDGE     (1u<<16)
+#define LD_EDGE     (UINT64_C(1)<<16)
 #define LD_EXIT     LD_EDGE
 /** Bandwidth accounting. */
-#define LD_ACCT     (1u<<17)
+#define LD_ACCT     (UINT64_C(1)<<17)
 /** Router history */
-#define LD_HIST     (1u<<18)
+#define LD_HIST     (UINT64_C(1)<<18)
 /** OR handshaking */
-#define LD_HANDSHAKE (1u<<19)
+#define LD_HANDSHAKE (UINT64_C(1)<<19)
 /** Heartbeat messages */
-#define LD_HEARTBEAT (1u<<20)
+#define LD_HEARTBEAT (UINT64_C(1)<<20)
 /** Abstract channel_t code */
-#define LD_CHANNEL   (1u<<21)
+#define LD_CHANNEL   (UINT64_C(1)<<21)
 /** Scheduler */
-#define LD_SCHED     (1u<<22)
+#define LD_SCHED     (UINT64_C(1)<<22)
 /** Guard nodes */
-#define LD_GUARD     (1u<<23)
+#define LD_GUARD     (UINT64_C(1)<<23)
 /** Generation and application of consensus diffs. */
-#define LD_CONSDIFF  (1u<<24)
+#define LD_CONSDIFF  (UINT64_C(1)<<24)
 /** Denial of Service mitigation. */
-#define LD_DOS       (1u<<25)
+#define LD_DOS       (UINT64_C(1)<<25)
 /** Processes */
-#define LD_PROCESS   (1u<<26)
+#define LD_PROCESS   (UINT64_C(1)<<26)
 /** Pluggable Transports. */
-#define LD_PT        (1u<<27)
+#define LD_PT        (UINT64_C(1)<<27)
 /** Bootstrap tracker. */
-#define LD_BTRACK    (1u<<28)
-/** Number of logging domains in the code. */
-#define N_LOGGING_DOMAINS 29
-
-/** This log message is not safe to send to a callback-based logger
- * immediately.  Used as a flag, not a log domain. */
-#define LD_NOCB (1u<<31)
-/** This log message should not include a function name, even if it otherwise
- * would. Used as a flag, not a log domain. */
-#define LD_NOFUNCNAME (1u<<30)
+#define LD_BTRACK    (UINT64_C(1)<<28)
+/** Message-passing backend. */
+#define LD_MESG      (UINT64_C(1)<<29)
+#define N_LOGGING_DOMAINS 30
 
+/** First bit that is reserved in log_domain_mask_t for non-domain flags. */
+#define LOWEST_RESERVED_LD_FLAG_ (UINT64_C(1)<<61)
 #ifdef TOR_UNIT_TESTS
 /** This log message should not be intercepted by mock_saving_logv */
-#define LD_NO_MOCK (1u<<29)
+#define LD_NO_MOCK (UINT64_C(1)<<61)
 #endif
 
-/** Mask of zero or more log domains, OR'd together. */
-typedef uint32_t log_domain_mask_t;
+/** This log message is not safe to send to a callback-based logger
+ * immediately.  Used as a flag, not a log domain. */
+#define LD_NOCB (UINT64_C(1)<<62)
+/** This log message should not include a function name, even if it otherwise
+ * would. Used as a flag, not a log domain. */
+#define LD_NOFUNCNAME (UINT64_C(1)<<63)
 
 /** Configures which severities are logged for each logging domain for a given
  * log target. */
@@ -140,7 +142,8 @@ typedef struct log_severity_list_t {
 } log_severity_list_t;
 
 /** Callback type used for add_callback_log. */
-typedef void (*log_callback)(int severity, uint32_t domain, const char *msg);
+typedef void (*log_callback)(int severity, log_domain_mask_t domain,
+                             const char *msg);
 
 void init_logging(int disable_startup_queue);
 int parse_log_level(const char *level);
@@ -192,6 +195,21 @@ void tor_log_get_logfile_names(struct smartlist_t *out);
 
 extern int log_global_min_severity_;
 
+#ifdef TOR_COVERAGE
+/* For coverage builds, we try to avoid our log_debug optimization, since it
+ * can have weird effects on internal macro coverage. */
+#define debug_logging_enabled() (1)
+#else
+static inline bool debug_logging_enabled(void);
+/**
+ * Return true iff debug logging is enabled for at least one domain.
+ */
+static inline bool debug_logging_enabled(void)
+{
+  return PREDICT_UNLIKELY(log_global_min_severity_ == LOG_DEBUG);
+}
+#endif /* defined(TOR_COVERAGE) */
+
 void log_fn_(int severity, log_domain_mask_t domain,
              const char *funcname, const char *format, ...)
   CHECK_PRINTF(4,5);
@@ -221,8 +239,8 @@ void tor_log_string(int severity, log_domain_mask_t domain,
   log_fn_ratelim_(ratelim, severity, domain, __FUNCTION__, args)
 #define log_debug(domain, args...)                                      \
   STMT_BEGIN                                                            \
-    if (PREDICT_UNLIKELY(log_global_min_severity_ == LOG_DEBUG))        \
-      log_fn_(LOG_DEBUG, domain, __FUNCTION__, args);            \
+    if (debug_logging_enabled())                                        \
+      log_fn_(LOG_DEBUG, domain, __FUNCTION__, args);                   \
   STMT_END
 #define log_info(domain, args...)                           \
   log_fn_(LOG_INFO, domain, __FUNCTION__, args)
@@ -239,8 +257,8 @@ void tor_log_string(int severity, log_domain_mask_t domain,
 
 #define log_debug(domain, args, ...)                                        \
   STMT_BEGIN                                                                \
-    if (PREDICT_UNLIKELY(log_global_min_severity_ == LOG_DEBUG))            \
-      log_fn_(LOG_DEBUG, domain, __FUNCTION__, args, ##__VA_ARGS__); \
+    if (debug_logging_enabled())                                            \
+      log_fn_(LOG_DEBUG, domain, __FUNCTION__, args, ##__VA_ARGS__);        \
   STMT_END
 #define log_info(domain, args,...)                                      \
   log_fn_(LOG_INFO, domain, __FUNCTION__, args, ##__VA_ARGS__)
@@ -278,5 +296,4 @@ MOCK_DECL(STATIC void, logv, (int severity, log_domain_mask_t domain,
     va_list ap) CHECK_PRINTF(5,0));
 #endif
 
-# define TOR_TORLOG_H
 #endif /* !defined(TOR_TORLOG_H) */
diff --git a/src/lib/log/ratelim.h b/src/lib/log/ratelim.h
index 48edd7c84..1db54ba72 100644
--- a/src/lib/log/ratelim.h
+++ b/src/lib/log/ratelim.h
@@ -50,4 +50,4 @@ typedef struct ratelim_t {
 
 char *rate_limit_log(ratelim_t *lim, time_t now);
 
-#endif
+#endif /* !defined(TOR_RATELIM_H) */
diff --git a/src/lib/log/util_bug.c b/src/lib/log/util_bug.c
index c65a91ae9..76b97c1a0 100644
--- a/src/lib/log/util_bug.c
+++ b/src/lib/log/util_bug.c
@@ -70,25 +70,45 @@ tor_set_failed_assertion_callback(void (*fn)(void))
 
 /** Helper for tor_assert: report the assertion failure. */
 void
+CHECK_PRINTF(5, 6)
 tor_assertion_failed_(const char *fname, unsigned int line,
-                      const char *func, const char *expr)
+                      const char *func, const char *expr,
+                      const char *fmt, ...)
 {
-  char buf[256];
+  char *buf = NULL;
+  char *extra = NULL;
+  va_list ap;
+
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wformat-nonliteral"
+#endif
+  if (fmt) {
+    va_start(ap,fmt);
+    tor_vasprintf(&extra, fmt, ap);
+    va_end(ap);
+  }
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+
   log_err(LD_BUG, "%s:%u: %s: Assertion %s failed; aborting.",
           fname, line, func, expr);
-  tor_snprintf(buf, sizeof(buf),
-               "Assertion %s failed in %s at %s:%u",
-               expr, func, fname, line);
+  tor_asprintf(&buf, "Assertion %s failed in %s at %s:%u: %s",
+               expr, func, fname, line, extra ? extra : "");
+  tor_free(extra);
   log_backtrace(LOG_ERR, LD_BUG, buf);
+  tor_free(buf);
 }
 
 /** Helper for tor_assert_nonfatal: report the assertion failure. */
 void
+CHECK_PRINTF(6, 7)
 tor_bug_occurred_(const char *fname, unsigned int line,
                   const char *func, const char *expr,
-                  int once)
+                  int once, const char *fmt, ...)
 {
-  char buf[256];
+  char *buf = NULL;
   const char *once_str = once ?
     " (Future instances of this warning will be silenced.)": "";
   if (! expr) {
@@ -98,7 +118,7 @@ tor_bug_occurred_(const char *fname, unsigned int line,
     }
     log_warn(LD_BUG, "%s:%u: %s: This line should not have been reached.%s",
              fname, line, func, once_str);
-    tor_snprintf(buf, sizeof(buf),
+    tor_asprintf(&buf,
                  "Line unexpectedly reached at %s at %s:%u",
                  func, fname, line);
   } else {
@@ -106,13 +126,32 @@ tor_bug_occurred_(const char *fname, unsigned int line,
       add_captured_bug(expr);
       return;
     }
+
+    va_list ap;
+    char *extra = NULL;
+
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wformat-nonliteral"
+#endif
+    if (fmt) {
+      va_start(ap,fmt);
+      tor_vasprintf(&extra, fmt, ap);
+      va_end(ap);
+    }
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+
     log_warn(LD_BUG, "%s:%u: %s: Non-fatal assertion %s failed.%s",
              fname, line, func, expr, once_str);
-    tor_snprintf(buf, sizeof(buf),
-                 "Non-fatal assertion %s failed in %s at %s:%u",
-                 expr, func, fname, line);
+    tor_asprintf(&buf, "Non-fatal assertion %s failed in %s at %s:%u%s%s",
+                 expr, func, fname, line, fmt ? " : " : "",
+                 extra ? extra : "");
+    tor_free(extra);
   }
   log_backtrace(LOG_WARN, LD_BUG, buf);
+  tor_free(buf);
 
 #ifdef TOR_UNIT_TESTS
   if (failed_assertion_cb) {
diff --git a/src/lib/log/util_bug.h b/src/lib/log/util_bug.h
index 2a4d68127..546ae1e3e 100644
--- a/src/lib/log/util_bug.h
+++ b/src/lib/log/util_bug.h
@@ -80,10 +80,10 @@
     tor__assert_tmp_value__;                    \
   } )
 #define ASSERT_PREDICT_LIKELY_(e) ASSERT_PREDICT_UNLIKELY_(e)
-#else
+#else /* !(defined(TOR_UNIT_TESTS) && defined(__GNUC__)) */
 #define ASSERT_PREDICT_UNLIKELY_(e) PREDICT_UNLIKELY(e)
 #define ASSERT_PREDICT_LIKELY_(e) PREDICT_LIKELY(e)
-#endif
+#endif /* defined(TOR_UNIT_TESTS) && defined(__GNUC__) */
 
 /* Sometimes we don't want to use assertions during branch coverage tests; it
  * leads to tons of unreached branches which in reality are only assertions we
@@ -92,21 +92,28 @@
 #define tor_assert(a) STMT_BEGIN                                        \
   (void)(a);                                                            \
   STMT_END
-#else
+#define tor_assertf(a, fmt, ...) STMT_BEGIN                             \
+  (void)(a);                                                            \
+  (void)(fmt);                                                          \
+  STMT_END
+#else /* !(defined(TOR_UNIT_TESTS) && ... */
 /** Like assert(3), but send assertion failures to the log as well as to
  * stderr. */
-#define tor_assert(expr) STMT_BEGIN                                     \
+#define tor_assert(expr) tor_assertf(expr, NULL)
+
+#define tor_assertf(expr, fmt, ...) STMT_BEGIN                          \
   if (ASSERT_PREDICT_LIKELY_(expr)) {                                   \
   } else {                                                              \
-    tor_assertion_failed_(SHORT_FILE__, __LINE__, __func__, #expr);     \
-    tor_abort_();                                                       \
+    tor_assertion_failed_(SHORT_FILE__, __LINE__, __func__, #expr,      \
+                          fmt, ##__VA_ARGS__);                          \
+    tor_abort_();                                                        \
   } STMT_END
 #endif /* defined(TOR_UNIT_TESTS) && defined(DISABLE_ASSERTS_IN_UNIT_TESTS) */
 
 #define tor_assert_unreached()                                  \
   STMT_BEGIN {                                                  \
     tor_assertion_failed_(SHORT_FILE__, __LINE__, __func__,     \
-                          "line should be unreached");          \
+                          "line should be unreached", NULL);    \
     tor_abort_();                                               \
   } STMT_END
 
@@ -136,34 +143,47 @@
 #ifdef ALL_BUGS_ARE_FATAL
 #define tor_assert_nonfatal_unreached() tor_assert(0)
 #define tor_assert_nonfatal(cond) tor_assert((cond))
+#define tor_assertf_nonfatal(cond, fmt, ...)    \
+  tor_assertf(cond, fmt, ##__VA_ARGS__)
 #define tor_assert_nonfatal_unreached_once() tor_assert(0)
 #define tor_assert_nonfatal_once(cond) tor_assert((cond))
 #define BUG(cond)                                                       \
   (ASSERT_PREDICT_UNLIKELY_(cond) ?                                     \
-   (tor_assertion_failed_(SHORT_FILE__,__LINE__,__func__,"!("#cond")"), \
+   (tor_assertion_failed_(SHORT_FILE__,__LINE__,__func__,"!("#cond")",NULL), \
     tor_abort_(), 1)                                                    \
    : 0)
 #elif defined(TOR_UNIT_TESTS) && defined(DISABLE_ASSERTS_IN_UNIT_TESTS)
 #define tor_assert_nonfatal_unreached() STMT_NIL
 #define tor_assert_nonfatal(cond) ((void)(cond))
+#define tor_assertf_nonfatal(cond, fmt, ...) STMT_BEGIN                 \
+  (void)cond;                                                           \
+  (void)fmt;                                                            \
+  STMT_END
 #define tor_assert_nonfatal_unreached_once() STMT_NIL
 #define tor_assert_nonfatal_once(cond) ((void)(cond))
 #define BUG(cond) (ASSERT_PREDICT_UNLIKELY_(cond) ? 1 : 0)
 #else /* Normal case, !ALL_BUGS_ARE_FATAL, !DISABLE_ASSERTS_IN_UNIT_TESTS */
 #define tor_assert_nonfatal_unreached() STMT_BEGIN                      \
-  tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, NULL, 0);         \
+  tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, NULL, 0, NULL);   \
   STMT_END
 #define tor_assert_nonfatal(cond) STMT_BEGIN                            \
   if (ASSERT_PREDICT_LIKELY_(cond)) {                                   \
   } else {                                                              \
-    tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 0);      \
+    tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 0, NULL);\
+  }                                                                     \
+  STMT_END
+#define tor_assertf_nonfatal(cond, fmt, ...) STMT_BEGIN                 \
+  if (ASSERT_PREDICT_UNLIKELY_(cond)) {                                 \
+  } else {                                                              \
+    tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 0,        \
+                      fmt, ##__VA_ARGS__);                               \
   }                                                                     \
   STMT_END
 #define tor_assert_nonfatal_unreached_once() STMT_BEGIN                 \
   static int warning_logged__ = 0;                                      \
   if (!warning_logged__) {                                              \
     warning_logged__ = 1;                                               \
-    tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, NULL, 1);       \
+    tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, NULL, 1, NULL); \
   }                                                                     \
   STMT_END
 #define tor_assert_nonfatal_once(cond) STMT_BEGIN                       \
@@ -171,12 +191,12 @@
   if (ASSERT_PREDICT_LIKELY_(cond)) {                                   \
   } else if (!warning_logged__) {                                       \
     warning_logged__ = 1;                                               \
-    tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 1);      \
+    tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__, #cond, 1, NULL);\
   }                                                                     \
   STMT_END
 #define BUG(cond)                                                       \
   (ASSERT_PREDICT_UNLIKELY_(cond) ?                                     \
-   (tor_bug_occurred_(SHORT_FILE__,__LINE__,__func__,"!("#cond")",0), 1) \
+  (tor_bug_occurred_(SHORT_FILE__,__LINE__,__func__,"!("#cond")",1,NULL),1) \
    : 0)
 #endif /* defined(ALL_BUGS_ARE_FATAL) || ... */
 
@@ -188,7 +208,7 @@
       if (bool_result && !var) {                                        \
         var = 1;                                                        \
         tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__,             \
-                          "!("#cond")", 1);                             \
+                          "!("#cond")", 1, NULL);                       \
       }                                                                 \
       bool_result; } ))
 #else /* !(defined(__GNUC__)) */
@@ -198,7 +218,7 @@
       (var ? 1 :                                                        \
        (var=1,                                                          \
         tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__,             \
-                           "!("#cond")", 1),                            \
+                           "!("#cond")", 1, NULL),                      \
         1))                                                             \
       : 0)
 #endif /* defined(__GNUC__) */
@@ -221,10 +241,11 @@
 #define tor_fragile_assert() tor_assert_nonfatal_unreached_once()
 
 void tor_assertion_failed_(const char *fname, unsigned int line,
-                           const char *func, const char *expr);
+                           const char *func, const char *expr,
+                           const char *fmt, ...);
 void tor_bug_occurred_(const char *fname, unsigned int line,
                        const char *func, const char *expr,
-                       int once);
+                       int once, const char *fmt, ...);
 
 void tor_abort_(void) ATTR_NORETURN;
 
diff --git a/src/lib/log/win32err.h b/src/lib/log/win32err.h
index 33413dfd1..ecfa88792 100644
--- a/src/lib/log/win32err.h
+++ b/src/lib/log/win32err.h
@@ -19,4 +19,4 @@
 char *format_win32_error(DWORD err);
 #endif
 
-#endif
+#endif /* !defined(TOR_WIN32ERR_H) */
diff --git a/src/lib/malloc/include.am b/src/lib/malloc/include.am
index 95d96168e..b74292bc6 100644
--- a/src/lib/malloc/include.am
+++ b/src/lib/malloc/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-malloc-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_malloc_a_SOURCES =			\
 	src/lib/malloc/malloc.c				\
 	src/lib/malloc/map_anon.c
@@ -18,6 +19,7 @@ src_lib_libtor_malloc_testing_a_SOURCES = \
 src_lib_libtor_malloc_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_malloc_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/malloc/malloc.h				\
 	src/lib/malloc/map_anon.h
diff --git a/src/lib/malloc/malloc.h b/src/lib/malloc/malloc.h
index ef6b509ca..8c81d30dd 100644
--- a/src/lib/malloc/malloc.h
+++ b/src/lib/malloc/malloc.h
@@ -48,12 +48,12 @@ void tor_free_(void *mem);
     raw_free(*tor_free__tmpvar);                               \
     *tor_free__tmpvar=NULL;                                    \
   STMT_END
-#else
+#else /* !(defined(__GNUC__)) */
 #define tor_free(p) STMT_BEGIN                                 \
   raw_free(p);                                                 \
   (p)=NULL;                                                    \
   STMT_END
-#endif
+#endif /* defined(__GNUC__) */
 
 #define tor_malloc(size)       tor_malloc_(size)
 #define tor_malloc_zero(size)  tor_malloc_zero_(size)
diff --git a/src/lib/malloc/map_anon.c b/src/lib/malloc/map_anon.c
index 2fc6e89ea..0f6a4150c 100644
--- a/src/lib/malloc/map_anon.c
+++ b/src/lib/malloc/map_anon.c
@@ -50,12 +50,16 @@
 
 #ifdef INHERIT_ZERO
 #define FLAG_ZERO INHERIT_ZERO
+#elif defined(MAP_INHERIT_ZERO)
+#define FLAG_ZERO MAP_INHERIT_ZERO
 #endif
 #ifdef INHERIT_NONE
 #define FLAG_NOINHERIT INHERIT_NONE
 #elif defined(VM_INHERIT_NONE)
 #define FLAG_NOINHERIT VM_INHERIT_NONE
-#endif
+#elif defined(MAP_INHERIT_NONE)
+#define FLAG_NOINHERIT MAP_INHERIT_NONE
+#endif /* defined(INHERIT_NONE) || ... */
 
 #elif defined(HAVE_MADVISE)
 
@@ -68,6 +72,11 @@
 #define FLAG_NOINHERIT MADV_DONTFORK
 #endif
 
+#endif /* defined(HAVE_MINHERIT) || ... */
+
+#if defined(HAVE_MINHERIT) && !defined(FLAG_ZERO) && !defined(FLAG_NOINHERIT)
+#warn "minherit() is defined, but we couldn't find the right flag for it."
+#warn "This is probably a bug in Tor's support for this platform."
 #endif
 
 /**
@@ -87,7 +96,7 @@ lock_mem(void *mem, size_t sz)
   (void) sz;
 
   return 0;
-#endif
+#endif /* defined(_WIN32) || ... */
 }
 
 /**
@@ -104,7 +113,7 @@ nodump_mem(void *mem, size_t sz)
   (void) mem;
   (void) sz;
   return 0;
-#endif
+#endif /* defined(MADV_DONTDUMP) */
 }
 
 /**
@@ -113,22 +122,32 @@ nodump_mem(void *mem, size_t sz)
  * fork, and if that doesn't work, by having them unmapped after a fork.
  * Return 0 on success or if the facility is not available on this OS; return
  * -1 on failure.
+ *
+ * If we successfully make the memory uninheritable, adjust the value of
+ * *<b>inherit_result_out</b>.
  */
 static int
-noinherit_mem(void *mem, size_t sz)
+noinherit_mem(void *mem, size_t sz, inherit_res_t *inherit_result_out)
 {
 #ifdef FLAG_ZERO
   int r = MINHERIT(mem, sz, FLAG_ZERO);
-  if (r == 0)
+  if (r == 0) {
+    *inherit_result_out = INHERIT_RES_ZERO;
     return 0;
-#endif
+  }
+#endif /* defined(FLAG_ZERO) */
 #ifdef FLAG_NOINHERIT
-  return MINHERIT(mem, sz, FLAG_NOINHERIT);
-#else
+  int r2 = MINHERIT(mem, sz, FLAG_NOINHERIT);
+  if (r2 == 0) {
+    *inherit_result_out = INHERIT_RES_DROP;
+  }
+  return r2;
+#else /* !(defined(FLAG_NOINHERIT)) */
+  (void)inherit_result_out;
   (void)mem;
   (void)sz;
   return 0;
-#endif
+#endif /* defined(FLAG_NOINHERIT) */
 }
 
 /**
@@ -144,14 +163,25 @@ noinherit_mem(void *mem, size_t sz)
  * Memory returned from this function must be released with
  * tor_munmap_anonymous().
  *
+ * If <b>inherit_result_out</b> is non-NULL, set it to one of
+ * INHERIT_RES_KEEP, INHERIT_RES_DROP, or INHERIT_RES_ZERO, depending on the
+ * properties of the returned memory.
+ *
  * [Note: OS people use the word "anonymous" here to mean that the memory
  * isn't associated with any file. This has *nothing* to do with the kind of
  * anonymity that Tor is trying to provide.]
  */
 void *
-tor_mmap_anonymous(size_t sz, unsigned flags)
+tor_mmap_anonymous(size_t sz, unsigned flags,
+                   inherit_res_t *inherit_result_out)
 {
   void *ptr;
+  inherit_res_t itmp=0;
+  if (inherit_result_out == NULL) {
+    inherit_result_out = &itmp;
+  }
+  *inherit_result_out = INHERIT_RES_KEEP;
+
 #if defined(_WIN32)
   HANDLE mapping = CreateFileMapping(INVALID_HANDLE_VALUE,
                                      NULL, /*attributes*/
@@ -174,7 +204,7 @@ tor_mmap_anonymous(size_t sz, unsigned flags)
   raw_assert(ptr != NULL);
 #else
   ptr = tor_malloc_zero(sz);
-#endif
+#endif /* defined(_WIN32) || ... */
 
   if (flags & ANONMAP_PRIVATE) {
     int lock_result = lock_mem(ptr, sz);
@@ -184,7 +214,7 @@ tor_mmap_anonymous(size_t sz, unsigned flags)
   }
 
   if (flags & ANONMAP_NOINHERIT) {
-    int noinherit_result = noinherit_mem(ptr, sz);
+    int noinherit_result = noinherit_mem(ptr, sz, inherit_result_out);
     raw_assert(noinherit_result == 0);
   }
 
@@ -209,5 +239,5 @@ tor_munmap_anonymous(void *mapping, size_t sz)
 #else
   (void)sz;
   tor_free(mapping);
-#endif
+#endif /* defined(_WIN32) || ... */
 }
diff --git a/src/lib/malloc/map_anon.h b/src/lib/malloc/map_anon.h
index cc5797e4e..4c4690e12 100644
--- a/src/lib/malloc/map_anon.h
+++ b/src/lib/malloc/map_anon.h
@@ -31,7 +31,41 @@
  */
 #define ANONMAP_NOINHERIT (1u<<1)
 
-void *tor_mmap_anonymous(size_t sz, unsigned flags);
+typedef enum {
+  /** Possible value for inherit_result_out: the memory will be kept
+   * by any child process. */
+  INHERIT_RES_KEEP=0,
+  /** Possible value for inherit_result_out: the memory will be dropped in the
+   * child process. Attempting to access it will likely cause a segfault. */
+  INHERIT_RES_DROP,
+  /** Possible value for inherit_result_out: the memory will be cleared in
+   * the child process. */
+  INHERIT_RES_ZERO
+} inherit_res_t;
+
+/* Here we define the NOINHERIT_CAN_FAIL macro if and only if
+ * it's possible that ANONMAP_NOINHERIT might yield inheritable memory.
+ */
+#ifdef _WIN32
+/* Windows can't fork, so NOINHERIT is never needed. */
+#elif defined(HAVE_MINHERIT)
+/* minherit() will always have a working MAP_INHERIT_NONE or MAP_INHERIT_ZERO.
+ * NOINHERIT should always work.
+ */
+#elif defined(HAVE_MADVISE)
+/* madvise() sometimes has neither MADV_DONTFORK and MADV_WIPEONFORK.
+ * We need to be ready for the possibility it failed.
+ *
+ * (Linux added DONTFORK in 2.6.16 and WIPEONFORK in 4.14. If we someday
+ * require 2.6.16 or later, we can assume that DONTFORK will work.)
+ */
+#define NOINHERIT_CAN_FAIL
+#else
+#define NOINHERIT_CAN_FAIL
+#endif /* defined(_WIN32) || ... */
+
+void *tor_mmap_anonymous(size_t sz, unsigned flags,
+                         inherit_res_t *inherit_result_out);
 void tor_munmap_anonymous(void *mapping, size_t sz);
 
 #endif /* !defined(TOR_MAP_ANON_H) */
diff --git a/src/lib/math/fp.h b/src/lib/math/fp.h
index cb24649e6..a73789c94 100644
--- a/src/lib/math/fp.h
+++ b/src/lib/math/fp.h
@@ -21,4 +21,4 @@ int64_t tor_llround(double d) ATTR_CONST;
 int64_t clamp_double_to_int64(double number);
 int tor_isinf(double x);
 
-#endif
+#endif /* !defined(TOR_FP_H) */
diff --git a/src/lib/math/include.am b/src/lib/math/include.am
index 6d65ce90a..b2ca280f4 100644
--- a/src/lib/math/include.am
+++ b/src/lib/math/include.am
@@ -5,17 +5,18 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-math-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_math_a_SOURCES =	\
 		src/lib/math/fp.c		\
 		src/lib/math/laplace.c 	\
 		src/lib/math/prob_distr.c
 
-
 src_lib_libtor_math_testing_a_SOURCES = \
 	$(src_lib_libtor_math_a_SOURCES)
 src_lib_libtor_math_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_math_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=				\
 		src/lib/math/fp.h		\
 		src/lib/math/laplace.h  \
diff --git a/src/lib/math/laplace.h b/src/lib/math/laplace.h
index e8651e519..02b0e890f 100644
--- a/src/lib/math/laplace.h
+++ b/src/lib/math/laplace.h
@@ -19,4 +19,4 @@ int64_t sample_laplace_distribution(double mu, double b, double p);
 int64_t add_laplace_noise(int64_t signal, double random, double delta_f,
                           double epsilon);
 
-#endif
+#endif /* !defined(TOR_LAPLACE_H) */
diff --git a/src/lib/math/prob_distr.c b/src/lib/math/prob_distr.c
index c952dadc0..d44dc2826 100644
--- a/src/lib/math/prob_distr.c
+++ b/src/lib/math/prob_distr.c
@@ -46,26 +46,27 @@
 
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/cc/ctassert.h"
+#include "lib/log/util_bug.h"
 
 #include <float.h>
 #include <math.h>
 #include <stddef.h>
 
-/** Validators for downcasting macros below */
-#define validate_container_of(PTR, TYPE, FIELD)                         \
-  (0 * sizeof((PTR) - &((TYPE *)(((char *)(PTR)) -                      \
-      offsetof(TYPE, FIELD)))->FIELD))
-#define validate_const_container_of(PTR, TYPE, FIELD)                   \
-  (0 * sizeof((PTR) - &((const TYPE *)(((const char *)(PTR)) -          \
-      offsetof(TYPE, FIELD)))->FIELD))
-/** Downcasting macro */
-#define container_of(PTR, TYPE, FIELD)                                  \
-  ((TYPE *)(((char *)(PTR)) - offsetof(TYPE, FIELD))                    \
-    + validate_container_of(PTR, TYPE, FIELD))
-/** Constified downcasting macro */
-#define const_container_of(PTR, TYPE, FIELD)                            \
-  ((const TYPE *)(((const char *)(PTR)) - offsetof(TYPE, FIELD))        \
-    + validate_const_container_of(PTR, TYPE, FIELD))
+/** Declare a function that downcasts from a generic dist struct to the actual
+ *  subtype probablity distribution it represents. */
+#define DECLARE_PROB_DISTR_DOWNCAST_FN(name) \
+  static inline                           \
+  const struct name *                             \
+  dist_to_const_##name(const struct dist *obj) {    \
+    tor_assert(obj->ops == &name##_ops);            \
+    return SUBTYPE_P(obj, struct name, base);   \
+  }
+DECLARE_PROB_DISTR_DOWNCAST_FN(uniform)
+DECLARE_PROB_DISTR_DOWNCAST_FN(geometric)
+DECLARE_PROB_DISTR_DOWNCAST_FN(logistic)
+DECLARE_PROB_DISTR_DOWNCAST_FN(log_logistic)
+DECLARE_PROB_DISTR_DOWNCAST_FN(genpareto)
+DECLARE_PROB_DISTR_DOWNCAST_FN(weibull)
 
 /**
  * Count number of one bits in 32-bit word.
@@ -458,7 +459,7 @@ random_uniform_01(void)
    * system is broken.
    */
   z = 0;
-  while ((x = crypto_rand_u32()) == 0) {
+  while ((x = crypto_fast_rng_get_u32(get_thread_fast_rng())) == 0) {
     if (z >= 1088)
       /* Your bit sampler is broken.  Go home.  */
       return 0;
@@ -472,8 +473,8 @@ random_uniform_01(void)
    * occur only with measure zero in the uniform distribution on
    * [0, 1].
    */
-  hi = crypto_rand_u32() | UINT32_C(0x80000000);
-  lo = crypto_rand_u32() | UINT32_C(0x00000001);
+  hi = crypto_fast_rng_get_u32(get_thread_fast_rng()) | UINT32_C(0x80000000);
+  lo = crypto_fast_rng_get_u32(get_thread_fast_rng()) | UINT32_C(0x00000001);
 
   /* Round to nearest scaled significand in [2^63, 2^64].  */
   s = hi*(double)4294967296 + lo;
@@ -1315,40 +1316,48 @@ sample_geometric(uint32_t s, double p0, double p)
 
 /** Public API for probability distributions:
  *
- *  For each probability distribution we define each public functions
- *  (sample/cdf/sf/icdf/isf) as part of its dist_ops structure.
+ *  These are wrapper functions on top of the various probability distribution
+ *  operations using the generic <b>dist</b> structure.
+
+ *  These are the functions that should be used by consumers of this API.
  */
 
+/** Returns the name of the distribution in <b>dist</b>. */
 const char *
 dist_name(const struct dist *dist)
 {
   return dist->ops->name;
 }
 
+/* Sample a value from <b>dist</b> and return it. */
 double
 dist_sample(const struct dist *dist)
 {
   return dist->ops->sample(dist);
 }
 
+/** Compute the CDF of <b>dist</b> at <b>x</b>. */
 double
 dist_cdf(const struct dist *dist, double x)
 {
   return dist->ops->cdf(dist, x);
 }
 
+/** Compute the SF (Survival function) of <b>dist</b> at <b>x</b>. */
 double
 dist_sf(const struct dist *dist, double x)
 {
   return dist->ops->sf(dist, x);
 }
 
+/** Compute the iCDF (Inverse CDF) of <b>dist</b> at <b>x</b>. */
 double
 dist_icdf(const struct dist *dist, double p)
 {
   return dist->ops->icdf(dist, p);
 }
 
+/** Compute the iSF (Inverse Survival function) of <b>dist</b> at <b>x</b>. */
 double
 dist_isf(const struct dist *dist, double p)
 {
@@ -1360,8 +1369,7 @@ dist_isf(const struct dist *dist, double p)
 static double
 uniform_sample(const struct dist *dist)
 {
-  const struct uniform *U = const_container_of(dist, struct uniform,
-    base);
+  const struct uniform *U = dist_to_const_uniform(dist);
   double p0 = random_uniform_01();
 
   return sample_uniform_interval(p0, U->a, U->b);
@@ -1370,9 +1378,7 @@ uniform_sample(const struct dist *dist)
 static double
 uniform_cdf(const struct dist *dist, double x)
 {
-  const struct uniform *U = const_container_of(dist, struct uniform,
-    base);
-
+  const struct uniform *U = dist_to_const_uniform(dist);
   if (x < U->a)
     return 0;
   else if (x < U->b)
@@ -1384,8 +1390,7 @@ uniform_cdf(const struct dist *dist, double x)
 static double
 uniform_sf(const struct dist *dist, double x)
 {
-  const struct uniform *U = const_container_of(dist, struct uniform,
-    base);
+  const struct uniform *U = dist_to_const_uniform(dist);
 
   if (x > U->b)
     return 0;
@@ -1398,8 +1403,7 @@ uniform_sf(const struct dist *dist, double x)
 static double
 uniform_icdf(const struct dist *dist, double p)
 {
-  const struct uniform *U = const_container_of(dist, struct uniform,
-    base);
+  const struct uniform *U = dist_to_const_uniform(dist);
   double w = U->b - U->a;
 
   return (p < 0.5 ? (U->a + w*p) : (U->b - w*(1 - p)));
@@ -1408,8 +1412,7 @@ uniform_icdf(const struct dist *dist, double p)
 static double
 uniform_isf(const struct dist *dist, double p)
 {
-  const struct uniform *U = const_container_of(dist, struct uniform,
-    base);
+  const struct uniform *U = dist_to_const_uniform(dist);
   double w = U->b - U->a;
 
   return (p < 0.5 ? (U->b - w*p) : (U->a + w*(1 - p)));
@@ -1424,14 +1427,17 @@ const struct dist_ops uniform_ops = {
   .isf = uniform_isf,
 };
 
+/*******************************************************************/
+
+/** Private functions for each probability distribution. */
+
 /** Functions for logistic distribution: */
 
 static double
 logistic_sample(const struct dist *dist)
 {
-  const struct logistic *L = const_container_of(dist, struct logistic,
-    base);
-  uint32_t s = crypto_rand_u32();
+  const struct logistic *L = dist_to_const_logistic(dist);
+  uint32_t s = crypto_fast_rng_get_u32(get_thread_fast_rng());
   double t = random_uniform_01();
   double p0 = random_uniform_01();
 
@@ -1441,36 +1447,28 @@ logistic_sample(const struct dist *dist)
 static double
 logistic_cdf(const struct dist *dist, double x)
 {
-  const struct logistic *L = const_container_of(dist, struct logistic,
-    base);
-
+  const struct logistic *L = dist_to_const_logistic(dist);
   return cdf_logistic(x, L->mu, L->sigma);
 }
 
 static double
 logistic_sf(const struct dist *dist, double x)
 {
-  const struct logistic *L = const_container_of(dist, struct logistic,
-    base);
-
+  const struct logistic *L = dist_to_const_logistic(dist);
   return sf_logistic(x, L->mu, L->sigma);
 }
 
 static double
 logistic_icdf(const struct dist *dist, double p)
 {
-  const struct logistic *L = const_container_of(dist, struct logistic,
-    base);
-
+  const struct logistic *L = dist_to_const_logistic(dist);
   return icdf_logistic(p, L->mu, L->sigma);
 }
 
 static double
 logistic_isf(const struct dist *dist, double p)
 {
-  const struct logistic *L = const_container_of(dist, struct logistic,
-    base);
-
+  const struct logistic *L = dist_to_const_logistic(dist);
   return isf_logistic(p, L->mu, L->sigma);
 }
 
@@ -1488,9 +1486,8 @@ const struct dist_ops logistic_ops = {
 static double
 log_logistic_sample(const struct dist *dist)
 {
-  const struct log_logistic *LL = const_container_of(dist, struct
-    log_logistic, base);
-  uint32_t s = crypto_rand_u32();
+  const struct log_logistic *LL = dist_to_const_log_logistic(dist);
+  uint32_t s = crypto_fast_rng_get_u32(get_thread_fast_rng());
   double p0 = random_uniform_01();
 
   return sample_log_logistic_scaleshape(s, p0, LL->alpha, LL->beta);
@@ -1499,36 +1496,28 @@ log_logistic_sample(const struct dist *dist)
 static double
 log_logistic_cdf(const struct dist *dist, double x)
 {
-  const struct log_logistic *LL = const_container_of(dist,
-    struct log_logistic, base);
-
+  const struct log_logistic *LL = dist_to_const_log_logistic(dist);
   return cdf_log_logistic(x, LL->alpha, LL->beta);
 }
 
 static double
 log_logistic_sf(const struct dist *dist, double x)
 {
-  const struct log_logistic *LL = const_container_of(dist,
-    struct log_logistic, base);
-
+  const struct log_logistic *LL = dist_to_const_log_logistic(dist);
   return sf_log_logistic(x, LL->alpha, LL->beta);
 }
 
 static double
 log_logistic_icdf(const struct dist *dist, double p)
 {
-  const struct log_logistic *LL = const_container_of(dist,
-    struct log_logistic, base);
-
+  const struct log_logistic *LL = dist_to_const_log_logistic(dist);
   return icdf_log_logistic(p, LL->alpha, LL->beta);
 }
 
 static double
 log_logistic_isf(const struct dist *dist, double p)
 {
-  const struct log_logistic *LL = const_container_of(dist,
-    struct log_logistic, base);
-
+  const struct log_logistic *LL = dist_to_const_log_logistic(dist);
   return isf_log_logistic(p, LL->alpha, LL->beta);
 }
 
@@ -1546,9 +1535,8 @@ const struct dist_ops log_logistic_ops = {
 static double
 weibull_sample(const struct dist *dist)
 {
-  const struct weibull *W = const_container_of(dist, struct weibull,
-    base);
-  uint32_t s = crypto_rand_u32();
+  const struct weibull *W = dist_to_const_weibull(dist);
+  uint32_t s = crypto_fast_rng_get_u32(get_thread_fast_rng());
   double p0 = random_uniform_01();
 
   return sample_weibull(s, p0, W->lambda, W->k);
@@ -1557,36 +1545,28 @@ weibull_sample(const struct dist *dist)
 static double
 weibull_cdf(const struct dist *dist, double x)
 {
-  const struct weibull *W = const_container_of(dist, struct weibull,
-    base);
-
+  const struct weibull *W = dist_to_const_weibull(dist);
   return cdf_weibull(x, W->lambda, W->k);
 }
 
 static double
 weibull_sf(const struct dist *dist, double x)
 {
-  const struct weibull *W = const_container_of(dist, struct weibull,
-    base);
-
+  const struct weibull *W = dist_to_const_weibull(dist);
   return sf_weibull(x, W->lambda, W->k);
 }
 
 static double
 weibull_icdf(const struct dist *dist, double p)
 {
-  const struct weibull *W = const_container_of(dist, struct weibull,
-    base);
-
+  const struct weibull *W = dist_to_const_weibull(dist);
   return icdf_weibull(p, W->lambda, W->k);
 }
 
 static double
 weibull_isf(const struct dist *dist, double p)
 {
-  const struct weibull *W = const_container_of(dist, struct weibull,
-    base);
-
+  const struct weibull *W = dist_to_const_weibull(dist);
   return isf_weibull(p, W->lambda, W->k);
 }
 
@@ -1604,9 +1584,8 @@ const struct dist_ops weibull_ops = {
 static double
 genpareto_sample(const struct dist *dist)
 {
-  const struct genpareto *GP = const_container_of(dist, struct genpareto,
-    base);
-  uint32_t s = crypto_rand_u32();
+  const struct genpareto *GP = dist_to_const_genpareto(dist);
+  uint32_t s = crypto_fast_rng_get_u32(get_thread_fast_rng());
   double p0 = random_uniform_01();
 
   return sample_genpareto_locscale(s, p0, GP->mu, GP->sigma, GP->xi);
@@ -1615,36 +1594,28 @@ genpareto_sample(const struct dist *dist)
 static double
 genpareto_cdf(const struct dist *dist, double x)
 {
-  const struct genpareto *GP = const_container_of(dist, struct genpareto,
-    base);
-
+  const struct genpareto *GP = dist_to_const_genpareto(dist);
   return cdf_genpareto(x, GP->mu, GP->sigma, GP->xi);
 }
 
 static double
 genpareto_sf(const struct dist *dist, double x)
 {
-  const struct genpareto *GP = const_container_of(dist, struct genpareto,
-    base);
-
+  const struct genpareto *GP = dist_to_const_genpareto(dist);
   return sf_genpareto(x, GP->mu, GP->sigma, GP->xi);
 }
 
 static double
 genpareto_icdf(const struct dist *dist, double p)
 {
-  const struct genpareto *GP = const_container_of(dist, struct genpareto,
-    base);
-
+  const struct genpareto *GP = dist_to_const_genpareto(dist);
   return icdf_genpareto(p, GP->mu, GP->sigma, GP->xi);
 }
 
 static double
 genpareto_isf(const struct dist *dist, double p)
 {
-  const struct genpareto *GP = const_container_of(dist, struct genpareto,
-    base);
-
+  const struct genpareto *GP = dist_to_const_genpareto(dist);
   return isf_genpareto(p, GP->mu, GP->sigma, GP->xi);
 }
 
@@ -1662,8 +1633,8 @@ const struct dist_ops genpareto_ops = {
 static double
 geometric_sample(const struct dist *dist)
 {
-  const struct geometric *G = const_container_of(dist, struct geometric, base);
-  uint32_t s = crypto_rand_u32();
+  const struct geometric *G = dist_to_const_geometric(dist);
+  uint32_t s = crypto_fast_rng_get_u32(get_thread_fast_rng());
   double p0 = random_uniform_01();
 
   return sample_geometric(s, p0, G->p);
@@ -1672,7 +1643,7 @@ geometric_sample(const struct dist *dist)
 static double
 geometric_cdf(const struct dist *dist, double x)
 {
-  const struct geometric *G = const_container_of(dist, struct geometric, base);
+  const struct geometric *G = dist_to_const_geometric(dist);
 
   if (x < 1)
     return 0;
@@ -1683,7 +1654,7 @@ geometric_cdf(const struct dist *dist, double x)
 static double
 geometric_sf(const struct dist *dist, double x)
 {
-  const struct geometric *G = const_container_of(dist, struct geometric, base);
+  const struct geometric *G = dist_to_const_geometric(dist);
 
   if (x < 1)
     return 0;
@@ -1694,7 +1665,7 @@ geometric_sf(const struct dist *dist, double x)
 static double
 geometric_icdf(const struct dist *dist, double p)
 {
-  const struct geometric *G = const_container_of(dist, struct geometric, base);
+  const struct geometric *G = dist_to_const_geometric(dist);
 
   return log1p(-p)/log1p(-G->p);
 }
@@ -1702,7 +1673,7 @@ geometric_icdf(const struct dist *dist, double p)
 static double
 geometric_isf(const struct dist *dist, double p)
 {
-  const struct geometric *G = const_container_of(dist, struct geometric, base);
+  const struct geometric *G = dist_to_const_geometric(dist);
 
   return log(p)/log1p(-G->p);
 }
diff --git a/src/lib/math/prob_distr.h b/src/lib/math/prob_distr.h
index 66acb796f..7254dc862 100644
--- a/src/lib/math/prob_distr.h
+++ b/src/lib/math/prob_distr.h
@@ -19,10 +19,100 @@ struct dist {
   const struct dist_ops *ops;
 };
 
+/**
+ * Untyped initializer element for struct dist using the specified
+ * struct dist_ops pointer.  Don't actually use this directly -- use
+ * the type-specific macro built out of DIST_BASE_TYPED below -- but if
+ * you did use this directly, it would be something like:
+ *
+ *   struct weibull mydist = {
+ *     DIST_BASE(&weibull_ops),
+ *     .lambda = ...,
+ *     .k = ...,
+ *   };
+ *
+ * Note there is NO COMPILER FEEDBACK if you accidentally do something
+ * like
+ *
+ *   struct geometric mydist = {
+ *     DIST_BASE(&weibull_ops),
+ *     ...
+ *   };
+ */
 #define DIST_BASE(OPS)  { .ops = (OPS) }
+
+/** A compile-time type-checking macro for use with DIST_BASE_TYPED.
+ *
+ *  This macro works by checking that &OBJ is a pointer type that is the same
+ *  type (except for qualifiers) as (const TYPE *)&OBJ. It's a C constraint
+ *  violation (which requires a diagnostic) if two pointers are different types
+ *  and are subtracted. The sizeof() forces compile-time evaluation, and the
+ *  multiplication by zero is to discard the result of the sizeof() from the
+ *  expression.
+ *
+ *  We define this conditionally to suppress false positives from
+ *  Coverity, which gets confused by the sizeof business.
+ */
+#ifdef __COVERITY__
+#define TYPE_CHECK_OBJ(OPS, OBJ, TYPE) 0
+#else
+#define TYPE_CHECK_OBJ(OPS, OBJ, TYPE) \
+  (0*sizeof(&(OBJ) - (const TYPE *)&(OBJ)))
+#endif /* defined(__COVERITY__) */
+
+/**
+* Typed initializer element for struct dist using the specified struct
+* dist_ops pointer.  Don't actually use this directly -- use a
+* type-specific macro built out of it -- but if you did use this
+* directly, it would be something like:
+*
+*   struct weibull mydist = {
+*     DIST_BASE_TYPED(&weibull_ops, mydist, struct weibull),
+*     .lambda = ...,
+*     .k = ...,
+*   };
+*
+* If you want to define a distribution type, define a canonical set of
+* operations and define a type-specific initializer element like so:
+*
+*   struct foo {
+*     struct dist base;
+*     int omega;
+*     double tau;
+*     double phi;
+*   };
+*
+*   struct dist_ops foo_ops = ...;
+*
+*   #define FOO(OBJ) DIST_BASE_TYPED(&foo_ops, OBJ, struct foo)
+*
+* Then users can do:
+*
+*   struct foo mydist = {
+*     FOO(mydist),
+*     .omega = ...,
+*     .tau = ...,
+*     .phi = ...,
+*   };
+*
+* If you accidentally write
+*
+*   struct bar mydist = {
+*     FOO(mydist),
+*     ...
+*   };
+*
+* then the compiler will report a type mismatch in the sizeof
+* expression, which otherwise evaporates at runtime.
+*/
 #define DIST_BASE_TYPED(OPS, OBJ, TYPE)                         \
-  DIST_BASE((OPS) + 0*sizeof(&(OBJ) - (const TYPE *)&(OBJ)))
+  DIST_BASE((OPS) + TYPE_CHECK_OBJ(OPS,OBJ,TYPE))
 
+/**
+ * Generic operations on distributions.  These simply defer to the
+ * corresponding dist_ops function.  In the parlance of C++, these call
+ * virtual member functions.
+ */
 const char *dist_name(const struct dist *);
 double dist_sample(const struct dist *);
 double dist_cdf(const struct dist *, double x);
@@ -30,6 +120,11 @@ double dist_sf(const struct dist *, double x);
 double dist_icdf(const struct dist *, double p);
 double dist_isf(const struct dist *, double p);
 
+/**
+ * Set of operations on a potentially parametric family of
+ * distributions.  In the parlance of C++, this would be called a
+ * `vtable' and the members are virtual member functions.
+ */
 struct dist_ops {
   const char *name;
   double (*sample)(const struct dist *);
@@ -153,6 +248,6 @@ STATIC double icdf_genpareto(double p, double mu, double sigma, double xi);
 STATIC double isf_genpareto(double p, double mu, double sigma, double xi);
 STATIC double sample_genpareto(uint32_t s, double p0, double xi);
 
-#endif
+#endif /* defined(PROB_DISTR_PRIVATE) */
 
-#endif
+#endif /* !defined(TOR_PROB_DISTR_H) */
diff --git a/src/lib/memarea/include.am b/src/lib/memarea/include.am
index 94343dcea..83fb99ec7 100644
--- a/src/lib/memarea/include.am
+++ b/src/lib/memarea/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-memarea-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_memarea_a_SOURCES =			\
 	src/lib/memarea/memarea.c
 
@@ -13,5 +14,6 @@ src_lib_libtor_memarea_testing_a_SOURCES = \
 src_lib_libtor_memarea_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_memarea_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/memarea/memarea.h
diff --git a/src/lib/meminfo/include.am b/src/lib/meminfo/include.am
index d1fdde631..12c1bff72 100644
--- a/src/lib/meminfo/include.am
+++ b/src/lib/meminfo/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-meminfo-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_meminfo_a_SOURCES =			\
 	src/lib/meminfo/meminfo.c
 
@@ -13,5 +14,6 @@ src_lib_libtor_meminfo_testing_a_SOURCES = \
 src_lib_libtor_meminfo_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_meminfo_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/meminfo/meminfo.h
diff --git a/src/lib/meminfo/meminfo.h b/src/lib/meminfo/meminfo.h
index 2d64e1ab0..9580640f4 100644
--- a/src/lib/meminfo/meminfo.h
+++ b/src/lib/meminfo/meminfo.h
@@ -18,4 +18,4 @@
 void tor_log_mallinfo(int severity);
 MOCK_DECL(int, get_total_system_memory, (size_t *mem_out));
 
-#endif
+#endif /* !defined(TOR_MEMINFO_H) */
diff --git a/src/lib/net/address.c b/src/lib/net/address.c
index 214d8aa3e..546af800a 100644
--- a/src/lib/net/address.c
+++ b/src/lib/net/address.c
@@ -339,7 +339,7 @@ tor_addr_to_str(char *dest, const tor_addr_t *addr, size_t len, int decorate)
       break;
     case AF_INET6:
       /* Shortest addr [ :: ] + \0 */
-      if (len < (3 + (decorate ? 2 : 0)))
+      if (len < (3u + (decorate ? 2 : 0)))
         return NULL;
 
       if (decorate)
@@ -2027,8 +2027,12 @@ string_is_valid_nonrfc_hostname(const char *string)
 
   smartlist_split_string(components,string,".",0,0);
 
-  if (BUG(smartlist_len(components) == 0))
-    return 0; // LCOV_EXCL_LINE should be impossible given the earlier checks.
+  if (BUG(smartlist_len(components) == 0)) {
+    // LCOV_EXCL_START should be impossible given the earlier checks.
+    smartlist_free(components);
+    return 0;
+    // LCOV_EXCL_STOP
+  }
 
   /* Allow a single terminating '.' used rarely to indicate domains
    * are FQDNs rather than relative. */
diff --git a/src/lib/net/alertsock.h b/src/lib/net/alertsock.h
index c45f42be8..4d0d0dd57 100644
--- a/src/lib/net/alertsock.h
+++ b/src/lib/net/alertsock.h
@@ -42,4 +42,4 @@ typedef struct alert_sockets_t {
 int alert_sockets_create(alert_sockets_t *socks_out, uint32_t flags);
 void alert_sockets_close(alert_sockets_t *socks);
 
-#endif
+#endif /* !defined(TOR_ALERTSOCK_H) */
diff --git a/src/lib/net/buffers_net.h b/src/lib/net/buffers_net.h
index a3a90172a..5058dd0a2 100644
--- a/src/lib/net/buffers_net.h
+++ b/src/lib/net/buffers_net.h
@@ -31,4 +31,4 @@ int buf_read_from_pipe(struct buf_t *buf, int fd, size_t at_most,
 int buf_flush_to_pipe(struct buf_t *buf, int fd, size_t sz,
                       size_t *buf_flushlen);
 
-#endif /* !defined(TOR_BUFFERS_H) */
+#endif /* !defined(TOR_BUFFERS_NET_H) */
diff --git a/src/lib/net/gethostname.h b/src/lib/net/gethostname.h
index 69b0528bc..b3b77b058 100644
--- a/src/lib/net/gethostname.h
+++ b/src/lib/net/gethostname.h
@@ -16,4 +16,4 @@
 
 MOCK_DECL(int,tor_gethostname,(char *name, size_t namelen));
 
-#endif
+#endif /* !defined(TOR_GETHOSTNAME_H) */
diff --git a/src/lib/net/inaddr.h b/src/lib/net/inaddr.h
index 36352b65e..602573944 100644
--- a/src/lib/net/inaddr.h
+++ b/src/lib/net/inaddr.h
@@ -24,4 +24,4 @@ int tor_inet_ntoa(const struct in_addr *in, char *buf, size_t buf_len);
 const char *tor_inet_ntop(int af, const void *src, char *dst, size_t len);
 int tor_inet_pton(int af, const char *src, void *dst);
 
-#endif
+#endif /* !defined(TOR_INADDR_H) */
diff --git a/src/lib/net/inaddr_st.h b/src/lib/net/inaddr_st.h
index 806f2c096..230f29a63 100644
--- a/src/lib/net/inaddr_st.h
+++ b/src/lib/net/inaddr_st.h
@@ -104,4 +104,4 @@ struct sockaddr_in6 {
 };
 #endif /* !defined(HAVE_STRUCT_SOCKADDR_IN6) */
 
-#endif /* TOR_INADDR_ST_H */
+#endif /* !defined(TOR_INADDR_ST_H) */
diff --git a/src/lib/net/include.am b/src/lib/net/include.am
index 8a88f0f2a..485019f4b 100644
--- a/src/lib/net/include.am
+++ b/src/lib/net/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-net-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_net_a_SOURCES =			\
 	src/lib/net/address.c			\
 	src/lib/net/alertsock.c                 \
@@ -21,6 +22,7 @@ src_lib_libtor_net_testing_a_SOURCES = \
 src_lib_libtor_net_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_net_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=				\
 	src/lib/net/address.h			\
 	src/lib/net/alertsock.h                 \
diff --git a/src/lib/net/nettypes.h b/src/lib/net/nettypes.h
index 6209bbe18..0eb352c65 100644
--- a/src/lib/net/nettypes.h
+++ b/src/lib/net/nettypes.h
@@ -41,4 +41,4 @@ typedef int socklen_t;
 #define TOR_INVALID_SOCKET (-1)
 #endif /* defined(_WIN32) */
 
-#endif
+#endif /* !defined(TOR_NET_TYPES_H) */
diff --git a/src/lib/net/resolve.c b/src/lib/net/resolve.c
index 49c263faa..2dda491d1 100644
--- a/src/lib/net/resolve.c
+++ b/src/lib/net/resolve.c
@@ -421,7 +421,7 @@ tor_make_getaddrinfo_cache_active(void)
 {
   sandbox_getaddrinfo_is_active = 1;
 }
-#else
+#else /* !(defined(USE_SANDBOX_GETADDRINFO)) */
 void
 sandbox_disable_getaddrinfo_cache(void)
 {
@@ -430,4 +430,4 @@ void
 tor_make_getaddrinfo_cache_active(void)
 {
 }
-#endif
+#endif /* defined(USE_SANDBOX_GETADDRINFO) */
diff --git a/src/lib/net/resolve.h b/src/lib/net/resolve.h
index 0fb77f166..d11c902a9 100644
--- a/src/lib/net/resolve.h
+++ b/src/lib/net/resolve.h
@@ -55,4 +55,4 @@ void tor_free_getaddrinfo_cache(void);
 void sandbox_disable_getaddrinfo_cache(void);
 void tor_make_getaddrinfo_cache_active(void);
 
-#endif
+#endif /* !defined(TOR_RESOLVE_H) */
diff --git a/src/lib/net/socket.c b/src/lib/net/socket.c
index f978deeab..e824a0504 100644
--- a/src/lib/net/socket.c
+++ b/src/lib/net/socket.c
@@ -84,9 +84,9 @@ check_network_configuration(bool server_mode)
                "so your relay makes it harder to figure out how busy it is.");
     }
   }
-#else
+#else /* !(defined(__FreeBSD__)) */
   (void) server_mode;
-#endif
+#endif /* defined(__FreeBSD__) */
 }
 
 /* When set_max_file_sockets() is called, update this with the max file
@@ -487,11 +487,11 @@ tor_socketpair(int family, int type, int protocol, tor_socket_t fd[2])
   r = socketpair(family, type, protocol, fd);
   if (r < 0)
     return -errno;
-#else
+#else /* !(defined(HAVE_SOCKETPAIR) && !defined(_WIN32)) */
   r = tor_ersatz_socketpair(family, type, protocol, fd);
   if (r < 0)
     return -r;
-#endif
+#endif /* defined(HAVE_SOCKETPAIR) && !defined(_WIN32) */
 
 #if defined(FD_CLOEXEC)
   if (SOCKET_OK(fd[0])) {
diff --git a/src/lib/net/socket.h b/src/lib/net/socket.h
index 86ae336df..193ad91e4 100644
--- a/src/lib/net/socket.h
+++ b/src/lib/net/socket.h
@@ -116,4 +116,4 @@ const char *tor_socket_strerror(int e);
 #define SIO_IDEAL_SEND_BACKLOG_QUERY 0x4004747b
 #endif
 
-#endif
+#endif /* !defined(TOR_SOCKET_H) */
diff --git a/src/lib/net/socketpair.c b/src/lib/net/socketpair.c
index 15c706bec..3be7b26f7 100644
--- a/src/lib/net/socketpair.c
+++ b/src/lib/net/socketpair.c
@@ -22,11 +22,11 @@
 #include <windows.h>
 #define socket_errno() (WSAGetLastError())
 #define SOCKET_EPROTONOSUPPORT WSAEPROTONOSUPPORT
-#else
+#else /* !(defined(_WIN32)) */
 #define closesocket(x) close(x)
 #define socket_errno() (errno)
 #define SOCKET_EPROTONOSUPPORT EPROTONOSUPPORT
-#endif
+#endif /* defined(_WIN32) */
 
 #ifdef NEED_ERSATZ_SOCKETPAIR
 
diff --git a/src/lib/net/socketpair.h b/src/lib/net/socketpair.h
index 6be080388..582060697 100644
--- a/src/lib/net/socketpair.h
+++ b/src/lib/net/socketpair.h
@@ -16,4 +16,4 @@ int tor_ersatz_socketpair(int family, int type, int protocol,
                           tor_socket_t fd[2]);
 #endif
 
-#endif
+#endif /* !defined(TOR_SOCKETPAIR_H) */
diff --git a/src/lib/net/socks5_status.h b/src/lib/net/socks5_status.h
index e55242ce6..e55119e0b 100644
--- a/src/lib/net/socks5_status.h
+++ b/src/lib/net/socks5_status.h
@@ -29,4 +29,4 @@ typedef enum {
   SOCKS5_ADDRESS_TYPE_NOT_SUPPORTED = 0x08,
 } socks5_reply_status_t;
 
-#endif
+#endif /* !defined(TOR_SOCKS5_STATUS_H) */
diff --git a/src/lib/osinfo/include.am b/src/lib/osinfo/include.am
index 16c581260..84bd7feb0 100644
--- a/src/lib/osinfo/include.am
+++ b/src/lib/osinfo/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-osinfo-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_osinfo_a_SOURCES =			\
 	src/lib/osinfo/uname.c
 
@@ -13,5 +14,6 @@ src_lib_libtor_osinfo_testing_a_SOURCES = \
 src_lib_libtor_osinfo_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_osinfo_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/osinfo/uname.h
diff --git a/src/lib/osinfo/uname.h b/src/lib/osinfo/uname.h
index fcce62907..443a30d35 100644
--- a/src/lib/osinfo/uname.h
+++ b/src/lib/osinfo/uname.h
@@ -15,4 +15,4 @@
 
 MOCK_DECL(const char *, get_uname,(void));
 
-#endif
+#endif /* !defined(HAVE_TOR_UNAME_H) */
diff --git a/src/lib/process/daemon.h b/src/lib/process/daemon.h
index 20920e0aa..423c49883 100644
--- a/src/lib/process/daemon.h
+++ b/src/lib/process/daemon.h
@@ -18,4 +18,4 @@ int finish_daemon(const char *desired_cwd);
 
 bool start_daemon_has_been_called(void);
 
-#endif
+#endif /* !defined(TOR_DAEMON_H) */
diff --git a/src/lib/process/env.h b/src/lib/process/env.h
index 15d59351e..19c223597 100644
--- a/src/lib/process/env.h
+++ b/src/lib/process/env.h
@@ -38,4 +38,4 @@ void set_environment_variable_in_smartlist(struct smartlist_t *env_vars,
                                            const char *new_var,
                                            void (*free_old)(void*),
                                            int free_p);
-#endif
+#endif /* !defined(TOR_ENV_H) */
diff --git a/src/lib/process/include.am b/src/lib/process/include.am
index 83b67bf02..af5f99617 100644
--- a/src/lib/process/include.am
+++ b/src/lib/process/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-process-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_process_a_SOURCES =		\
 	src/lib/process/daemon.c		\
 	src/lib/process/env.c			\
@@ -23,6 +24,7 @@ src_lib_libtor_process_testing_a_SOURCES = \
 src_lib_libtor_process_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_process_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=				\
 	src/lib/process/daemon.h		\
 	src/lib/process/env.h			\
diff --git a/src/lib/process/pidfile.h b/src/lib/process/pidfile.h
index dfeb39e04..af59041f8 100644
--- a/src/lib/process/pidfile.h
+++ b/src/lib/process/pidfile.h
@@ -13,4 +13,4 @@
 
 int write_pidfile(const char *filename);
 
-#endif
+#endif /* !defined(TOR_PIDFILE_H) */
diff --git a/src/lib/process/process.c b/src/lib/process/process.c
index 422942dc8..631c7169f 100644
--- a/src/lib/process/process.c
+++ b/src/lib/process/process.c
@@ -83,7 +83,7 @@ struct process_t {
 #else
   /** Our Win32 process handle. */
   process_win32_t *win32_process;
-#endif
+#endif /* !defined(_WIN32) */
 };
 
 /** Convert a given process status in <b>status</b> to its string
@@ -205,7 +205,7 @@ process_new(const char *command)
 #else
   /* Prepare our Win32 process handle. */
   process->win32_process = process_win32_new();
-#endif
+#endif /* !defined(_WIN32) */
 
   smartlist_add(processes, process);
 
@@ -240,7 +240,7 @@ process_free_(process_t *process)
 #else
   /* Cleanup our Win32 process handle. */
   process_win32_free(process->win32_process);
-#endif
+#endif /* !defined(_WIN32) */
 
   smartlist_remove(processes, process);
 
@@ -513,7 +513,7 @@ process_get_unix_process(const process_t *process)
   tor_assert(process->unix_process);
   return process->unix_process;
 }
-#else
+#else /* !(!defined(_WIN32)) */
 /** Get the internal handle for Windows backend. */
 process_win32_t *
 process_get_win32_process(const process_t *process)
@@ -522,7 +522,7 @@ process_get_win32_process(const process_t *process)
   tor_assert(process->win32_process);
   return process->win32_process;
 }
-#endif
+#endif /* !defined(_WIN32) */
 
 /** Write <b>size</b> bytes of <b>data</b> to the given process's standard
  * input. */
diff --git a/src/lib/process/process.h b/src/lib/process/process.h
index 14069923a..05c091a5b 100644
--- a/src/lib/process/process.h
+++ b/src/lib/process/process.h
@@ -111,7 +111,7 @@ struct process_unix_t *process_get_unix_process(const process_t *process);
 #else
 struct process_win32_t;
 struct process_win32_t *process_get_win32_process(const process_t *process);
-#endif
+#endif /* !defined(_WIN32) */
 
 void process_write(process_t *process,
                    const uint8_t *data, size_t size);
@@ -140,6 +140,6 @@ STATIC void process_read_buffer(process_t *process,
 STATIC void process_read_lines(process_t *process,
                                buf_t *buffer,
                                process_read_callback_t callback);
-#endif /* defined(PROCESS_PRIVATE). */
+#endif /* defined(PROCESS_PRIVATE) */
 
-#endif /* defined(TOR_PROCESS_H). */
+#endif /* !defined(TOR_PROCESS_H) */
diff --git a/src/lib/process/process_unix.c b/src/lib/process/process_unix.c
index 790ab897e..17ade8746 100644
--- a/src/lib/process/process_unix.c
+++ b/src/lib/process/process_unix.c
@@ -702,4 +702,4 @@ process_unix_close_file_descriptors(process_unix_t *unix_process)
   return success;
 }
 
-#endif /* defined(_WIN32). */
+#endif /* !defined(_WIN32) */
diff --git a/src/lib/process/process_unix.h b/src/lib/process/process_unix.h
index a1d8f7299..da40b3e56 100644
--- a/src/lib/process/process_unix.h
+++ b/src/lib/process/process_unix.h
@@ -61,8 +61,8 @@ STATIC int process_unix_read_handle(process_t *,
                                     process_unix_handle_t *,
                                     buf_t *);
 STATIC bool process_unix_close_file_descriptors(process_unix_t *);
-#endif /* defined(PROCESS_UNIX_PRIVATE). */
+#endif /* defined(PROCESS_UNIX_PRIVATE) */
 
-#endif /* defined(_WIN32). */
+#endif /* !defined(_WIN32) */
 
-#endif /* defined(TOR_PROCESS_UNIX_H). */
+#endif /* !defined(TOR_PROCESS_UNIX_H) */
diff --git a/src/lib/process/process_win32.c b/src/lib/process/process_win32.c
index ddbe76bfd..624333d4a 100644
--- a/src/lib/process/process_win32.c
+++ b/src/lib/process/process_win32.c
@@ -741,7 +741,7 @@ process_win32_cleanup_handle(process_win32_handle_t *handle)
                format_win32_error(error_code));
     }
   }
-#endif
+#endif /* 0 */
 
   /* Close our handle. */
   if (handle->pipe != INVALID_HANDLE_VALUE) {
@@ -1084,4 +1084,4 @@ tor_join_win_cmdline(const char *argv[])
   return joined_argv;
 }
 
-#endif /* ! defined(_WIN32). */
+#endif /* defined(_WIN32) */
diff --git a/src/lib/process/process_win32.h b/src/lib/process/process_win32.h
index d79dde157..a50d86df5 100644
--- a/src/lib/process/process_win32.h
+++ b/src/lib/process/process_win32.h
@@ -90,8 +90,8 @@ STATIC bool process_win32_handle_read_completion(process_win32_handle_t *,
 
 STATIC char *format_win_cmdline_argument(const char *arg);
 STATIC char *tor_join_win_cmdline(const char *argv[]);
-#endif /* defined(PROCESS_WIN32_PRIVATE). */
+#endif /* defined(PROCESS_WIN32_PRIVATE) */
 
-#endif /* ! defined(_WIN32). */
+#endif /* defined(_WIN32) */
 
-#endif /* defined(TOR_PROCESS_WIN32_H). */
+#endif /* !defined(TOR_PROCESS_WIN32_H) */
diff --git a/src/lib/process/setuid.h b/src/lib/process/setuid.h
index 7d03e1f02..a2125d2d0 100644
--- a/src/lib/process/setuid.h
+++ b/src/lib/process/setuid.h
@@ -19,4 +19,4 @@ int have_capability_support(void);
 #define SWITCH_ID_WARN_IF_NO_CAPS (1<<1)
 int switch_id(const char *user, unsigned flags);
 
-#endif
+#endif /* !defined(TOR_SETUID_H) */
diff --git a/src/lib/process/winprocess_sys.c b/src/lib/process/winprocess_sys.c
index 1266babca..48c088865 100644
--- a/src/lib/process/winprocess_sys.c
+++ b/src/lib/process/winprocess_sys.c
@@ -51,7 +51,7 @@ subsys_winprocess_initialize(void)
 
   return 0;
 }
-#else  /* !defined(_WIN32) */
+#else /* !(defined(_WIN32)) */
 #define WINPROCESS_SYS_ENABLED false
 #define subsys_winprocess_initialize NULL
 #endif /* defined(_WIN32) */
diff --git a/src/lib/pubsub/.may_include b/src/lib/pubsub/.may_include
new file mode 100644
index 000000000..5623492f0
--- /dev/null
+++ b/src/lib/pubsub/.may_include
@@ -0,0 +1,10 @@
+orconfig.h
+
+lib/cc/*.h
+lib/container/*.h
+lib/dispatch/*.h
+lib/intmath/*.h
+lib/log/*.h
+lib/malloc/*.h
+lib/pubsub/*.h
+lib/string/*.h
diff --git a/src/lib/pubsub/include.am b/src/lib/pubsub/include.am
new file mode 100644
index 000000000..e2abebcd4
--- /dev/null
+++ b/src/lib/pubsub/include.am
@@ -0,0 +1,28 @@
+
+noinst_LIBRARIES += src/lib/libtor-pubsub.a
+
+if UNITTESTS_ENABLED
+noinst_LIBRARIES += src/lib/libtor-pubsub-testing.a
+endif
+
+# ADD_C_FILE: INSERT SOURCES HERE.
+src_lib_libtor_pubsub_a_SOURCES =			\
+	src/lib/pubsub/pubsub_build.c			\
+	src/lib/pubsub/pubsub_check.c			\
+	src/lib/pubsub/pubsub_publish.c
+
+src_lib_libtor_pubsub_testing_a_SOURCES = \
+	$(src_lib_libtor_pubsub_a_SOURCES)
+src_lib_libtor_pubsub_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
+src_lib_libtor_pubsub_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+
+# ADD_C_FILE: INSERT HEADERS HERE.
+noinst_HEADERS +=					\
+	src/lib/pubsub/pub_binding_st.h			\
+	src/lib/pubsub/pubsub.h				\
+	src/lib/pubsub/pubsub_build.h			\
+	src/lib/pubsub/pubsub_builder_st.h		\
+	src/lib/pubsub/pubsub_connect.h			\
+	src/lib/pubsub/pubsub_flags.h			\
+	src/lib/pubsub/pubsub_macros.h			\
+	src/lib/pubsub/pubsub_publish.h
diff --git a/src/lib/pubsub/pub_binding_st.h b/src/lib/pubsub/pub_binding_st.h
new file mode 100644
index 000000000..d841bf3f5
--- /dev/null
+++ b/src/lib/pubsub/pub_binding_st.h
@@ -0,0 +1,38 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file pub_binding_st.h
+ * @brief Declaration of pub_binding_t.
+ *
+ * This is an internal type for the pubsub implementation.
+ */
+
+#ifndef TOR_PUB_BINDING_ST_H
+#define TOR_PUB_BINDING_ST_H
+
+#include "lib/dispatch/msgtypes.h"
+struct dispatch_t;
+
+/**
+ * A pub_binding_t is an opaque object that subsystems use to publish
+ * messages.  The DISPATCH_ADD_PUB*() macros set it up.
+ **/
+typedef struct pub_binding_t {
+  /**
+   * A pointer to a configured dispatch_t object.  This is filled in
+   * when the dispatch_t is finally constructed.
+   **/
+  struct dispatch_t *dispatch_ptr;
+  /**
+   * A template for the msg_t fields that are filled in for this message.
+   * This is copied into outgoing messages, ensuring that their fields are set
+   * corretly.
+   **/
+  msg_t msg_template;
+} pub_binding_t;
+
+#endif /* !defined(TOR_PUB_BINDING_ST_H) */
diff --git a/src/lib/pubsub/pubsub.h b/src/lib/pubsub/pubsub.h
new file mode 100644
index 000000000..5346b0751
--- /dev/null
+++ b/src/lib/pubsub/pubsub.h
@@ -0,0 +1,89 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file pubsub.h
+ * @brief Header for OO publish-subscribe functionality.
+ *
+ * This module provides a wrapper around the "dispatch" module,
+ * ensuring type-safety and allowing us to do static analysis on
+ * publication and subscriptions.
+ *
+ * With this module, we enforce:
+ *  <ul>
+ *   <li>that every message has (potential) publishers and subscribers;
+ *   <li>that every message is published and subscribed from the correct
+ *       channels, with the correct type ID, every time it is published.
+ *   <li>that type IDs correspond to a single C type, and that the C types are
+ *       used correctly.
+ *   <li>that when a message is published or subscribed, it is done with
+ *       a correct subsystem identifier
+ * </ul>
+ *
+ * We do this by making "publication requests" and "subscription requests"
+ * into objects, and doing some computation on them before we create
+ * a dispatch_t with them.
+ *
+ * Rather than using the dispatch module directly, a publishing module
+ * receives a "binding" object that it uses to send messages with the right
+ * settings.
+ *
+ * Most users of this module will want to use this header, and the
+ * pubsub_macros.h header for convenience.
+ */
+
+/*
+ *
+ * Overview: Messages are sent over channels.  Before sending a message on a
+ * channel, or receiving a message on a channel, a subsystem needs to register
+ * that it publishes, or subscribes, to that message, on that channel.
+ *
+ * Messages, channels, and subsystems are represented internally as short
+ * integers, though they are associated with human-readable strings for
+ * initialization and debugging.
+ *
+ * When registering for a message, a subsystem must say whether it is an
+ * exclusive publisher/subscriber to that message type, or whether other
+ * subsystems may also publish/subscribe to it.
+ *
+ * All messages and their publishers/subscribers must be registered early in
+ * the initialization process.
+ *
+ * By default, it is an error for a message type to have publishers and no
+ * subscribers on a channel, or subscribers and no publishers on a channel.
+ *
+ * A subsystem may register for a message with a note that delivery or
+ * production is disabled -- for example, because the subsystem is
+ * disabled at compile-time. It is not an error for a message type to
+ * have all of its publishers or subscribers disabled.
+ *
+ * After a message is sent, it is delivered to every recipient.  This
+ * delivery happens from the top level of the event loop; it may be
+ * interleaved with network events, timers, etc.
+ *
+ * Messages may have associated data.  This data is typed, and is owned
+ * by the message.  Strings, byte-arrays, and integers have built-in
+ * support.  Other types may be added.  If objects are to be sent,
+ * they should be identified by handle.  If an object requires cleanup,
+ * it should be declared with an associated free function.
+ *
+ * Semantically, if two subsystems communicate only by this kind of
+ * message passing, neither is considered to depend on the other, though
+ * both are considered to have a dependency on the message and on any
+ * types it contains.
+ *
+ * (Or generational index?)
+ */
+#ifndef TOR_PUBSUB_PUBSUB_H
+#define TOR_PUBSUB_PUBSUB_H
+
+#include "lib/pubsub/pub_binding_st.h"
+#include "lib/pubsub/pubsub_connect.h"
+#include "lib/pubsub/pubsub_flags.h"
+#include "lib/pubsub/pubsub_macros.h"
+#include "lib/pubsub/pubsub_publish.h"
+
+#endif /* !defined(TOR_PUBSUB_PUBSUB_H) */
diff --git a/src/lib/pubsub/pubsub_build.c b/src/lib/pubsub/pubsub_build.c
new file mode 100644
index 000000000..e44b7d76e
--- /dev/null
+++ b/src/lib/pubsub/pubsub_build.c
@@ -0,0 +1,307 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file pubsub_build.c
+ * @brief Construct a dispatch_t in safer, more OO way.
+ **/
+
+#define PUBSUB_PRIVATE
+
+#include "lib/dispatch/dispatch.h"
+#include "lib/dispatch/dispatch_cfg.h"
+#include "lib/dispatch/dispatch_naming.h"
+#include "lib/dispatch/msgtypes.h"
+#include "lib/pubsub/pubsub_flags.h"
+#include "lib/pubsub/pub_binding_st.h"
+#include "lib/pubsub/pubsub_build.h"
+#include "lib/pubsub/pubsub_builder_st.h"
+#include "lib/pubsub/pubsub_connect.h"
+
+#include "lib/container/smartlist.h"
+#include "lib/log/util_bug.h"
+#include "lib/malloc/malloc.h"
+
+ #include <string.h>
+
+/** Construct and return a new empty pubsub_items_t. */
+static pubsub_items_t *
+pubsub_items_new(void)
+{
+  pubsub_items_t *cfg = tor_malloc_zero(sizeof(*cfg));
+  cfg->items = smartlist_new();
+  cfg->type_items = smartlist_new();
+  return cfg;
+}
+
+/** Release all storage held in a pubsub_items_t. */
+void
+pubsub_items_free_(pubsub_items_t *cfg)
+{
+  if (! cfg)
+    return;
+  SMARTLIST_FOREACH(cfg->items, pubsub_cfg_t *, item, tor_free(item));
+  SMARTLIST_FOREACH(cfg->type_items,
+                    pubsub_type_cfg_t *, item, tor_free(item));
+  smartlist_free(cfg->items);
+  smartlist_free(cfg->type_items);
+  tor_free(cfg);
+}
+
+/** Construct and return a new pubsub_builder_t. */
+pubsub_builder_t *
+pubsub_builder_new(void)
+{
+  dispatch_naming_init();
+
+  pubsub_builder_t *pb = tor_malloc_zero(sizeof(*pb));
+  pb->cfg = dcfg_new();
+  pb->items = pubsub_items_new();
+  return pb;
+}
+
+/**
+ * Release all storage held by a pubsub_builder_t.
+ *
+ * You'll (mostly) only want to call this function on an error case: if you're
+ * constructing a dispatch_t instead, you should call
+ * pubsub_builder_finalize() to consume the pubsub_builder_t.
+ */
+void
+pubsub_builder_free_(pubsub_builder_t *pb)
+{
+  if (pb == NULL)
+    return;
+  pubsub_items_free(pb->items);
+  dcfg_free(pb->cfg);
+  tor_free(pb);
+}
+
+/**
+ * Create and return a pubsub_connector_t for the subsystem with ID
+ * <b>subsys</b> to use in adding publications, subscriptions, and types to
+ * <b>builder</b>.
+ **/
+pubsub_connector_t *
+pubsub_connector_for_subsystem(pubsub_builder_t *builder,
+                               subsys_id_t subsys)
+{
+  tor_assert(builder);
+  ++builder->n_connectors;
+
+  pubsub_connector_t *con = tor_malloc_zero(sizeof(*con));
+
+  con->builder = builder;
+  con->subsys_id = subsys;
+
+  return con;
+}
+
+/**
+ * Release all storage held by a pubsub_connector_t.
+ **/
+void
+pubsub_connector_free_(pubsub_connector_t *con)
+{
+  if (!con)
+    return;
+
+  if (con->builder) {
+    --con->builder->n_connectors;
+    tor_assert(con->builder->n_connectors >= 0);
+  }
+  tor_free(con);
+}
+
+/**
+ * Use <b>con</b> to add a request for being able to publish messages of type
+ * <b>msg</b> with auxiliary data of <b>type</b> on <b>channel</b>.
+ **/
+int
+pubsub_add_pub_(pubsub_connector_t *con,
+                pub_binding_t *out,
+                channel_id_t channel,
+                message_id_t msg,
+                msg_type_id_t type,
+                unsigned flags,
+                const char *file,
+                unsigned line)
+{
+  pubsub_cfg_t *cfg = tor_malloc_zero(sizeof(*cfg));
+
+  memset(out, 0, sizeof(*out));
+  cfg->is_publish = true;
+
+  out->msg_template.sender = cfg->subsys = con->subsys_id;
+  out->msg_template.channel = cfg->channel = channel;
+  out->msg_template.msg = cfg->msg = msg;
+  out->msg_template.type = cfg->type = type;
+
+  cfg->flags = flags;
+  cfg->added_by_file = file;
+  cfg->added_by_line = line;
+
+  /* We're grabbing a pointer to the pub_binding_t so we can tell it about
+   * the dispatcher later on.
+   */
+  cfg->pub_binding = out;
+
+  smartlist_add(con->builder->items->items, cfg);
+
+  if (dcfg_msg_set_type(con->builder->cfg, msg, type) < 0)
+    goto err;
+  if (dcfg_msg_set_chan(con->builder->cfg, msg, channel) < 0)
+    goto err;
+
+  return 0;
+ err:
+  ++con->builder->n_errors;
+  return -1;
+}
+
+/**
+ * Use <b>con</b> to add a request for being able to publish messages of type
+ * <b>msg</b> with auxiliary data of <b>type</b> on <b>channel</b>,
+ * passing them to the callback in <b>recv_fn</b>.
+ **/
+int
+pubsub_add_sub_(pubsub_connector_t *con,
+                recv_fn_t recv_fn,
+                channel_id_t channel,
+                message_id_t msg,
+                msg_type_id_t type,
+                unsigned flags,
+                const char *file,
+                unsigned line)
+{
+  pubsub_cfg_t *cfg = tor_malloc_zero(sizeof(*cfg));
+
+  cfg->is_publish = false;
+  cfg->subsys = con->subsys_id;
+  cfg->channel = channel;
+  cfg->msg = msg;
+  cfg->type = type;
+  cfg->flags = flags;
+  cfg->added_by_file = file;
+  cfg->added_by_line = line;
+
+  cfg->recv_fn = recv_fn;
+
+  smartlist_add(con->builder->items->items, cfg);
+
+  if (dcfg_msg_set_type(con->builder->cfg, msg, type) < 0)
+    goto err;
+  if (dcfg_msg_set_chan(con->builder->cfg, msg, channel) < 0)
+    goto err;
+  if (! (flags & DISP_FLAG_STUB)) {
+    if (dcfg_add_recv(con->builder->cfg, msg, cfg->subsys, recv_fn) < 0)
+      goto err;
+  }
+
+  return 0;
+ err:
+  ++con->builder->n_errors;
+  return -1;
+}
+
+/**
+ * Use <b>con</b> to define the functions to use for manipulating the type
+ * <b>type</b>.  Any function pointers left as NULL will be implemented as
+ * no-ops.
+ **/
+int
+pubsub_connector_register_type_(pubsub_connector_t *con,
+                                msg_type_id_t type,
+                                dispatch_typefns_t *fns,
+                                const char *file,
+                                unsigned line)
+{
+  pubsub_type_cfg_t *cfg = tor_malloc_zero(sizeof(*cfg));
+  cfg->type = type;
+  memcpy(&cfg->fns, fns, sizeof(*fns));
+  cfg->subsys = con->subsys_id;
+  cfg->added_by_file = file;
+  cfg->added_by_line = line;
+
+  smartlist_add(con->builder->items->type_items, cfg);
+
+  if (dcfg_type_set_fns(con->builder->cfg, type, fns) < 0)
+    goto err;
+
+  return 0;
+ err:
+  ++con->builder->n_errors;
+  return -1;
+}
+
+/**
+ * Initialize the dispatch_ptr field in every relevant publish binding
+ * for <b>d</b>.
+ */
+static void
+pubsub_items_install_bindings(pubsub_items_t *items,
+                              dispatch_t *d)
+{
+  SMARTLIST_FOREACH_BEGIN(items->items, pubsub_cfg_t *, cfg) {
+    if (cfg->pub_binding) {
+      // XXXX we could skip this for STUB publishers, and for any publishers
+      // XXXX where all subscribers are STUB.
+      cfg->pub_binding->dispatch_ptr = d;
+    }
+  } SMARTLIST_FOREACH_END(cfg);
+}
+
+/**
+ * Remove the dispatch_ptr fields for all the relevant publish bindings
+ * in <b>items</b>.  The prevents subsequent dispatch_pub_() calls from
+ * sending messages to a dispatcher that has been freed.
+ **/
+void
+pubsub_items_clear_bindings(pubsub_items_t *items)
+{
+  SMARTLIST_FOREACH_BEGIN(items->items, pubsub_cfg_t *, cfg) {
+    if (cfg->pub_binding) {
+      cfg->pub_binding->dispatch_ptr = NULL;
+    }
+  } SMARTLIST_FOREACH_END(cfg);
+}
+
+/**
+ * Create a new dispatcher as configured in a pubsub_builder_t.
+ *
+ * Consumes and frees its input.
+ **/
+dispatch_t *
+pubsub_builder_finalize(pubsub_builder_t *builder,
+                        pubsub_items_t **items_out)
+{
+  dispatch_t *dispatcher = NULL;
+  tor_assert_nonfatal(builder->n_connectors == 0);
+
+  if (pubsub_builder_check(builder) < 0)
+    goto err;
+
+  if (builder->n_errors) {
+    log_warn(LD_GENERAL, "At least one error occurred previously when "
+             "configuring the dispatcher.");
+    goto err;
+  }
+
+  dispatcher = dispatch_new(builder->cfg);
+
+  if (!dispatcher)
+    goto err;
+
+  pubsub_items_install_bindings(builder->items, dispatcher);
+  if (items_out) {
+    *items_out = builder->items;
+    builder->items = NULL; /* Prevent free */
+  }
+
+ err:
+  pubsub_builder_free(builder);
+  return dispatcher;
+}
diff --git a/src/lib/pubsub/pubsub_build.h b/src/lib/pubsub/pubsub_build.h
new file mode 100644
index 000000000..5a0c5f5bd
--- /dev/null
+++ b/src/lib/pubsub/pubsub_build.h
@@ -0,0 +1,92 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file pubsub_build.h
+ * @brief Header used for constructing the OO publish-subscribe facility.
+ *
+ * (See pubsub.h for more general information on this API.)
+ **/
+
+#ifndef TOR_PUBSUB_BUILD_H
+#define TOR_PUBSUB_BUILD_H
+
+#include "lib/dispatch/msgtypes.h"
+
+struct dispatch_t;
+struct pubsub_connector_t;
+
+/**
+ * A "dispatch builder" is an incomplete dispatcher, used when
+ * registering messages.  It does not have the same integrity guarantees
+ * as a dispatcher.  It cannot actually handle messages itself: once all
+ * subsystems have registered, it is converted into a dispatch_t.
+ **/
+typedef struct pubsub_builder_t pubsub_builder_t;
+
+/**
+ * A "pubsub items" holds the configuration items used to configure a
+ * pubsub_builder.  After the builder is finalized, this field is extracted,
+ * and used later to tear down pointers that enable publishing.
+ **/
+typedef struct pubsub_items_t pubsub_items_t;
+
+/**
+ * Create a new pubsub_builder. This should only happen in the
+ * main-init code.
+ */
+pubsub_builder_t *pubsub_builder_new(void);
+
+/** DOCDOC */
+int pubsub_builder_check(pubsub_builder_t *);
+
+/**
+ * Free a pubsub builder.  This should only happen on error paths, where
+ * we have decided not to construct a dispatcher for some reason.
+ */
+#define pubsub_builder_free(db) \
+  FREE_AND_NULL(pubsub_builder_t, pubsub_builder_free_, (db))
+
+/** Internal implementation of pubsub_builder_free(). */
+void pubsub_builder_free_(pubsub_builder_t *);
+
+/**
+ * Create a pubsub connector that a single subsystem will use to
+ * register its messages.  The main-init code does this during susbsystem
+ * initialization.
+ */
+struct pubsub_connector_t *pubsub_connector_for_subsystem(pubsub_builder_t *,
+                                                          subsys_id_t);
+
+/**
+ * The main-init code does this after subsystem initialization.
+ */
+#define pubsub_connector_free(c) \
+  FREE_AND_NULL(struct pubsub_connector_t, pubsub_connector_free_, (c))
+
+void pubsub_connector_free_(struct pubsub_connector_t *);
+
+/**
+ * Constructs a dispatcher from a dispatch_builder, after checking that the
+ * invariances on the messages, channels, and connections have been
+ * respected.
+ *
+ * This should happen after every subsystem has initialized, and before
+ * entering the mainloop.
+ */
+struct dispatch_t *pubsub_builder_finalize(pubsub_builder_t *,
+                                           pubsub_items_t **items_out);
+
+/**
+ * Clear all pub_binding_t backpointers in <b>items</b>.
+ **/
+void pubsub_items_clear_bindings(pubsub_items_t *items);
+
+#define pubsub_items_free(cfg) \
+  FREE_AND_NULL(pubsub_items_t, pubsub_items_free_, (cfg))
+void pubsub_items_free_(pubsub_items_t *cfg);
+
+#endif /* !defined(TOR_PUBSUB_BUILD_H) */
diff --git a/src/lib/pubsub/pubsub_builder_st.h b/src/lib/pubsub/pubsub_builder_st.h
new file mode 100644
index 000000000..545aa3f3e
--- /dev/null
+++ b/src/lib/pubsub/pubsub_builder_st.h
@@ -0,0 +1,161 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file pubsub_builder_st.h
+ *
+ * @brief private structures used for configuring dispatchers and messages.
+ */
+
+#ifndef TOR_PUBSUB_BUILDER_ST_H
+#define TOR_PUBSUB_BUILDER_ST_H
+
+#ifdef PUBSUB_PRIVATE
+
+#include <stdbool.h>
+#include <stddef.h>
+
+struct dispatch_cfg_t;
+struct smartlist_t;
+struct pub_binding_t;
+
+/**
+ * Configuration for a single publication or subscription request.
+ *
+ * These can be stored while the dispatcher is in use, but are only used for
+ * setup, teardown, and debugging.
+ *
+ * There are various fields in this request describing the message; all of
+ * them must match other descriptions of the message, or a bug has occurred.
+ **/
+typedef struct pubsub_cfg_t {
+  /** True if this is a publishing request; false for a subscribing request. */
+  bool is_publish;
+  /** The system making this request. */
+  subsys_id_t subsys;
+  /** The channel on which the message is to be sent. */
+  channel_id_t channel;
+  /** The message ID to be sent or received. */
+  message_id_t msg;
+  /** The C type associated with the message. */
+  msg_type_id_t type;
+  /** One or more DISP_FLAGS_* items, combined with bitwise OR. */
+  unsigned flags;
+
+  /**
+   * Publishing only: a pub_binding object that will receive the binding for
+   * this request.  We will finish filling this in when the dispatcher is
+   * constructed, so that the subsystem can publish then and not before.
+   */
+  struct pub_binding_t *pub_binding;
+
+  /**
+   * Subscribing only: a function to receive message objects for this request.
+   */
+  recv_fn_t recv_fn;
+
+  /** The file from which this message was configured */
+  const char *added_by_file;
+  /** The line at which this message was configured */
+  unsigned added_by_line;
+} pubsub_cfg_t;
+
+/**
+ * Configuration request for a single C type.
+ *
+ * These are stored while the dispatcher is in use, but are only used for
+ * setup, teardown, and debugging.
+ **/
+typedef struct pubsub_type_cfg_t {
+  /**
+   * The identifier for this type.
+   */
+  msg_type_id_t type;
+  /**
+   * Functions to use when manipulating the type.
+   */
+  dispatch_typefns_t fns;
+
+  /** The subsystem that configured this type. */
+  subsys_id_t subsys;
+  /** The file from which this type was configured */
+  const char *added_by_file;
+  /** The line at which this type was configured */
+  unsigned added_by_line;
+} pubsub_type_cfg_t;
+
+/**
+ * The set of configuration requests for a dispatcher, as made by various
+ * subsystems.
+ **/
+struct pubsub_items_t {
+  /** List of pubsub_cfg_t. */
+  struct smartlist_t *items;
+  /** List of pubsub_type_cfg_t. */
+  struct smartlist_t *type_items;
+};
+
+/**
+ * Type used to construct a dispatcher.  We use this type to build up the
+ * configuration for a dispatcher, and then pass ownership of that
+ * configuration to the newly constructed dispatcher.
+ **/
+struct pubsub_builder_t {
+  /** Number of outstanding pubsub_connector_t objects pointing to this
+   * pubsub_builder_t. */
+  int n_connectors;
+  /** Number of errors encountered while constructing this object so far. */
+  int n_errors;
+  /** In-progress configuration that we're constructing, as a list of the
+   * requests that have been made. */
+  struct pubsub_items_t *items;
+  /** In-progress configuration that we're constructing, in a form that can
+   * be converted to a dispatch_t. */
+  struct dispatch_cfg_t *cfg;
+};
+
+/**
+ * Type given to a subsystem when adding connections to a pubsub_builder_t.
+ * We use this type to force each subsystem to get blamed for the
+ * publications, subscriptions, and types that it adds.
+ **/
+struct pubsub_connector_t {
+  /** The pubsub_builder that this connector refers to. */
+  struct pubsub_builder_t *builder;
+  /** The subsystem that has been given this connector. */
+  subsys_id_t subsys_id;
+};
+
+/**
+ * Helper structure used when constructing a dispatcher that sorts the
+ * pubsub_cfg_t objects in various ways.
+ **/
+typedef struct pubsub_adjmap_t {
+  /* XXXX The next three fields are currently constructed but not yet
+   * XXXX used. I believe we'll want them in the future, though. -nickm
+   */
+  /** Number of subsystems; length of the *_by_subsys arrays. */
+  size_t n_subsystems;
+  /** Array of lists of publisher pubsub_cfg_t objects, indexed by
+   * subsystem. */
+  struct smartlist_t **pub_by_subsys;
+  /** Array of lists of subscriber pubsub_cfg_t objects, indexed by
+   * subsystem. */
+  struct smartlist_t **sub_by_subsys;
+
+  /** Number of message IDs; length of the *_by_msg arrays. */
+  size_t n_msgs;
+  /** Array of lists of publisher pubsub_cfg_t objects, indexed by
+   * message ID. */
+  struct smartlist_t **pub_by_msg;
+  /** Array of lists of subscriber pubsub_cfg_t objects, indexed by
+   * message ID. */
+  struct smartlist_t **sub_by_msg;
+} pubsub_adjmap_t;
+
+#endif /* defined(PUBSUB_PRIVATE) */
+
+#endif /* !defined(TOR_PUBSUB_BUILDER_ST_H) */
diff --git a/src/lib/pubsub/pubsub_check.c b/src/lib/pubsub/pubsub_check.c
new file mode 100644
index 000000000..a3c22d4f2
--- /dev/null
+++ b/src/lib/pubsub/pubsub_check.c
@@ -0,0 +1,428 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file pubsub_check.c
+ * @brief Enforce various requirements on a pubsub_builder.
+ **/
+
+#define PUBSUB_PRIVATE
+
+#include "lib/dispatch/dispatch_naming.h"
+#include "lib/dispatch/msgtypes.h"
+#include "lib/pubsub/pubsub_flags.h"
+#include "lib/pubsub/pubsub_builder_st.h"
+#include "lib/pubsub/pubsub_build.h"
+
+#include "lib/container/bitarray.h"
+#include "lib/container/smartlist.h"
+#include "lib/log/util_bug.h"
+#include "lib/malloc/malloc.h"
+#include "lib/string/compat_string.h"
+
+#include <string.h>
+
+static void pubsub_adjmap_add(pubsub_adjmap_t *map,
+                                const pubsub_cfg_t *item);
+
+/**
+ * Helper: contruct and return a new pubsub_adjacency_map from <b>cfg</b>.
+ * Return NULL on error.
+ **/
+static pubsub_adjmap_t *
+pubsub_build_adjacency_map(const pubsub_items_t *cfg)
+{
+  pubsub_adjmap_t *map = tor_malloc_zero(sizeof(*map));
+  const size_t n_subsystems = get_num_subsys_ids();
+  const size_t n_msgs = get_num_message_ids();
+
+  map->n_subsystems = n_subsystems;
+  map->n_msgs = n_msgs;
+
+  map->pub_by_subsys = tor_calloc(n_subsystems, sizeof(smartlist_t*));
+  map->sub_by_subsys = tor_calloc(n_subsystems, sizeof(smartlist_t*));
+  map->pub_by_msg = tor_calloc(n_msgs, sizeof(smartlist_t*));
+  map->sub_by_msg = tor_calloc(n_msgs, sizeof(smartlist_t*));
+
+  SMARTLIST_FOREACH_BEGIN(cfg->items, const pubsub_cfg_t *, item) {
+    pubsub_adjmap_add(map, item);
+  } SMARTLIST_FOREACH_END(item);
+
+  return map;
+}
+
+/**
+ * Helper: add a single pubsub_cfg_t to an adjacency map.
+ **/
+static void
+pubsub_adjmap_add(pubsub_adjmap_t *map,
+                  const pubsub_cfg_t *item)
+{
+  smartlist_t **by_subsys;
+  smartlist_t **by_msg;
+
+  tor_assert(item->subsys < map->n_subsystems);
+  tor_assert(item->msg < map->n_msgs);
+
+  if (item->is_publish) {
+    by_subsys = &map->pub_by_subsys[item->subsys];
+    by_msg = &map->pub_by_msg[item->msg];
+  } else {
+    by_subsys = &map->sub_by_subsys[item->subsys];
+    by_msg = &map->sub_by_msg[item->msg];
+  }
+
+  if (! *by_subsys)
+    *by_subsys = smartlist_new();
+  if (! *by_msg)
+    *by_msg = smartlist_new();
+  smartlist_add(*by_subsys, (void*) item);
+  smartlist_add(*by_msg, (void *) item);
+}
+
+/**
+ * Release all storage held by m and set m to NULL.
+ **/
+#define pubsub_adjmap_free(m) \
+  FREE_AND_NULL(pubsub_adjmap_t, pubsub_adjmap_free_, m)
+
+/**
+ * Free every element of an <b>n</b>-element array of smartlists, then
+ * free the array itself.
+ **/
+static void
+pubsub_adjmap_free_helper(smartlist_t **lsts, size_t n)
+{
+  if (!lsts)
+    return;
+
+  for (unsigned i = 0; i < n; ++i) {
+    smartlist_free(lsts[i]);
+  }
+  tor_free(lsts);
+}
+
+/**
+ * Release all storage held by <b>map</b>.
+ **/
+static void
+pubsub_adjmap_free_(pubsub_adjmap_t *map)
+{
+  if (!map)
+    return;
+  pubsub_adjmap_free_helper(map->pub_by_subsys, map->n_subsystems);
+  pubsub_adjmap_free_helper(map->sub_by_subsys, map->n_subsystems);
+  pubsub_adjmap_free_helper(map->pub_by_msg, map->n_msgs);
+  pubsub_adjmap_free_helper(map->sub_by_msg, map->n_msgs);
+  tor_free(map);
+}
+
+/**
+ * Helper: return the length of <b>sl</b>, or 0 if sl is NULL.
+ **/
+static int
+smartlist_len_opt(const smartlist_t *sl)
+{
+  if (sl)
+    return smartlist_len(sl);
+  else
+    return 0;
+}
+
+/** Return a pointer to a statically allocated string encoding the
+ * dispatcher flags in <b>flags</b>. */
+static const char *
+format_flags(unsigned flags)
+{
+  static char buf[32];
+  buf[0] = 0;
+  if (flags & DISP_FLAG_EXCL) {
+    strlcat(buf, " EXCL", sizeof(buf));
+  }
+  if (flags & DISP_FLAG_STUB) {
+    strlcat(buf, " STUB", sizeof(buf));
+  }
+  return buf[0] ? buf+1 : buf;
+}
+
+/**
+ * Log a message containing a description of <b>cfg</b> at severity, prefixed
+ * by the string <b>prefix</b>.
+ */
+static void
+pubsub_cfg_dump(const pubsub_cfg_t *cfg, int severity, const char *prefix)
+{
+  tor_assert(prefix);
+
+  tor_log(severity, LD_MESG,
+          "%s%s %s: %s{%s} on %s (%s) <%u %u %u %u %x> [%s:%d]",
+          prefix,
+          get_subsys_id_name(cfg->subsys),
+          cfg->is_publish ? "PUB" : "SUB",
+          get_message_id_name(cfg->msg),
+          get_msg_type_id_name(cfg->type),
+          get_channel_id_name(cfg->channel),
+          format_flags(cfg->flags),
+          cfg->subsys, cfg->msg, cfg->type, cfg->channel, cfg->flags,
+          cfg->added_by_file, cfg->added_by_line);
+}
+
+/**
+ * Helper: fill a bitarray <b>out</b> with entries corresponding to the
+ * subsystems listed in <b>items</b>.  If any subsystem is listed more than
+ * once, log a warning.  Return 0 on success, -1 on failure.
+ **/
+static int
+get_message_bitarray(const pubsub_adjmap_t *map,
+                     message_id_t msg,
+                     const smartlist_t *items,
+                     const char *operation,
+                     bitarray_t **out)
+{
+  bool ok = true;
+  *out = bitarray_init_zero((unsigned)map->n_subsystems);
+  if (! items)
+    return 0;
+
+  SMARTLIST_FOREACH_BEGIN(items, const pubsub_cfg_t *, cfg) {
+    if (bitarray_is_set(*out, cfg->subsys)) {
+      log_warn(LD_MESG|LD_BUG,
+               "Message \"%s\" is configured to be %s by subsystem "
+               "\"%s\" more than once.",
+               get_message_id_name(msg), operation,
+               get_subsys_id_name(cfg->subsys));
+      ok = false;
+    }
+    bitarray_set(*out, cfg->subsys);
+  } SMARTLIST_FOREACH_END(cfg);
+
+  return ok ? 0 : -1;
+}
+
+/**
+ * Helper for lint_message: check that all the pubsub_cfg_t items in the two
+ * respective smartlists obey our local graph topology rules.
+ *
+ * (Right now this is just a matter of "each subsystem only
+ * publishes/subscribes once; no subsystem is a publisher and subscriber for
+ * the same message.")
+ *
+ * Return 0 on success, -1 on failure.
+ **/
+static int
+lint_message_graph(const pubsub_adjmap_t *map,
+                   message_id_t msg,
+                   const smartlist_t *pub,
+                   const smartlist_t *sub)
+{
+  bitarray_t *published_by = NULL;
+  bitarray_t *subscribed_by = NULL;
+  bool ok = true;
+
+  if (get_message_bitarray(map, msg, pub, "published", &published_by) < 0)
+    ok = false;
+  if (get_message_bitarray(map, msg, sub, "subscribed", &subscribed_by) < 0)
+    ok = false;
+
+  /* Check whether any subsystem is publishing and subscribing the same
+   * message. [??]
+   */
+  for (unsigned i = 0; i < map->n_subsystems; ++i) {
+    if (bitarray_is_set(published_by, i) &&
+        bitarray_is_set(subscribed_by, i)) {
+      log_warn(LD_MESG|LD_BUG,
+               "Message \"%s\" is published and subscribed by the same "
+               "subsystem \"%s\".",
+               get_message_id_name(msg),
+               get_subsys_id_name(i));
+      ok = false;
+    }
+  }
+
+  bitarray_free(published_by);
+  bitarray_free(subscribed_by);
+
+  return ok ? 0 : -1;
+}
+
+/**
+ * Helper for lint_message: check that all the pubsub_cfg_t items in the two
+ * respective smartlists have compatible flags, channels, and types.
+ **/
+static int
+lint_message_consistency(message_id_t msg,
+                         const smartlist_t *pub,
+                         const smartlist_t *sub)
+{
+  if (!smartlist_len_opt(pub) && !smartlist_len_opt(sub))
+    return 0; // LCOV_EXCL_LINE -- this was already checked.
+
+  /* The 'all' list has the publishers and the subscribers. */
+  smartlist_t *all = smartlist_new();
+  if (pub)
+    smartlist_add_all(all, pub);
+  if (sub)
+    smartlist_add_all(all, sub);
+
+  const pubsub_cfg_t *item0 = smartlist_get(all, 0);
+
+  /* Indicates which subsystems we've found publishing/subscribing here. */
+  bool pub_excl = false, sub_excl = false, chan_same = true, type_same = true;
+
+  /* Simple message consistency properties across messages.
+   */
+  SMARTLIST_FOREACH_BEGIN(all, const pubsub_cfg_t *, cfg) {
+    chan_same &= (cfg->channel == item0->channel);
+    type_same &= (cfg->type == item0->type);
+    if (cfg->is_publish)
+      pub_excl |= (cfg->flags & DISP_FLAG_EXCL) != 0;
+    else
+      sub_excl |= (cfg->flags & DISP_FLAG_EXCL) != 0;
+  } SMARTLIST_FOREACH_END(cfg);
+
+  bool ok = true;
+
+  if (! chan_same) {
+    log_warn(LD_MESG|LD_BUG,
+             "Message \"%s\" is associated with multiple inconsistent "
+             "channels.",
+             get_message_id_name(msg));
+    ok = false;
+  }
+  if (! type_same) {
+    log_warn(LD_MESG|LD_BUG,
+             "Message \"%s\" is associated with multiple inconsistent "
+             "message types.",
+             get_message_id_name(msg));
+    ok = false;
+  }
+
+  /* Enforce exclusive-ness for publishers and subscribers that have asked for
+   * it.
+   */
+  if (pub_excl && smartlist_len_opt(pub) > 1) {
+    log_warn(LD_MESG|LD_BUG,
+             "Message \"%s\" has multiple publishers, but at least one is "
+             "marked as exclusive.",
+             get_message_id_name(msg));
+    ok = false;
+  }
+  if (sub_excl && smartlist_len_opt(sub) > 1) {
+    log_warn(LD_MESG|LD_BUG,
+             "Message \"%s\" has multiple subscribers, but at least one is "
+             "marked as exclusive.",
+             get_message_id_name(msg));
+    ok = false;
+  }
+
+  smartlist_free(all);
+
+  return ok ? 0 : -1;
+}
+
+/**
+ * Check whether there are any errors or inconsistencies for the message
+ * described by <b>msg</b> in <b>map</b>.  If there are problems, log about
+ * them, and return -1.  Otherwise return 0.
+ **/
+static int
+lint_message(const pubsub_adjmap_t *map, message_id_t msg)
+{
+  /* NOTE: Some of the checks in this function are maybe over-zealous, and we
+   * might not want to have them forever.  I've marked them with [?] below.
+   */
+  if (BUG(msg >= map->n_msgs))
+    return 0; // LCOV_EXCL_LINE
+
+  const smartlist_t *pub = map->pub_by_msg[msg];
+  const smartlist_t *sub = map->sub_by_msg[msg];
+
+  const size_t n_pub = smartlist_len_opt(pub);
+  const size_t n_sub = smartlist_len_opt(sub);
+
+  if (n_pub == 0 && n_sub == 0) {
+    log_info(LD_MESG, "Nobody is publishing or subscribing to message "
+             "\"%s\".",
+             get_message_id_name(msg));
+    return 0; // No publishers or subscribers: nothing to do.
+  }
+  /* We'll set this to false if there are any problems. */
+  bool ok = true;
+
+  /* First make sure that if there are publishers, there are subscribers. */
+  if (n_pub == 0) {
+    log_warn(LD_MESG|LD_BUG,
+             "Message \"%s\" has subscribers, but no publishers.",
+             get_message_id_name(msg));
+    ok = false;
+  } else if (n_sub == 0) {
+    log_warn(LD_MESG|LD_BUG,
+             "Message \"%s\" has publishers, but no subscribers.",
+             get_message_id_name(msg));
+    ok = false;
+  }
+
+  /* Check the message graph topology. */
+  if (lint_message_graph(map, msg, pub, sub) < 0)
+    ok = false;
+
+  /* Check whether the messages have the same fields set on them. */
+  if (lint_message_consistency(msg, pub, sub) < 0)
+    ok = false;
+
+  if (!ok) {
+    /* There was a problem -- let's log all the publishers and subscribers on
+     * this message */
+    if (pub) {
+      SMARTLIST_FOREACH(pub, pubsub_cfg_t *, cfg,
+                        pubsub_cfg_dump(cfg, LOG_WARN, "   "));
+    }
+    if (sub) {
+      SMARTLIST_FOREACH(sub, pubsub_cfg_t *, cfg,
+                        pubsub_cfg_dump(cfg, LOG_WARN, "   "));
+    }
+  }
+
+  return ok ? 0 : -1;
+}
+
+/**
+ * Check all the messages in <b>map</b> for consistency.  Return 0 on success,
+ * -1 on problems.
+ **/
+static int
+pubsub_adjmap_check(const pubsub_adjmap_t *map)
+{
+  bool all_ok = true;
+  for (unsigned i = 0; i < map->n_msgs; ++i) {
+    if (lint_message(map, i) < 0) {
+      all_ok = false;
+    }
+  }
+  return all_ok ? 0 : -1;
+}
+
+/**
+ * Check builder for consistency and various constraints. Return 0 on success,
+ * -1 on failure.
+ **/
+int
+pubsub_builder_check(pubsub_builder_t *builder)
+{
+  pubsub_adjmap_t *map = pubsub_build_adjacency_map(builder->items);
+  int rv = -1;
+
+  if (!map)
+    goto err; // should be impossible
+
+  if (pubsub_adjmap_check(map) < 0)
+    goto err;
+
+  rv = 0;
+ err:
+  pubsub_adjmap_free(map);
+  return rv;
+}
diff --git a/src/lib/pubsub/pubsub_connect.h b/src/lib/pubsub/pubsub_connect.h
new file mode 100644
index 000000000..0ad106044
--- /dev/null
+++ b/src/lib/pubsub/pubsub_connect.h
@@ -0,0 +1,54 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file pubsub_connect.h
+ * @brief Header for functions that add relationships to a pubsub builder.
+ *
+ * These functions are used by modules that need to add publication and
+ * subscription requests.  Most users will want to call these functions
+ * indirectly, via the macros in pubsub_macros.h.
+ **/
+
+#ifndef TOR_PUBSUB_CONNECT_H
+#define TOR_PUBSUB_CONNECT_H
+
+#include "lib/dispatch/msgtypes.h"
+
+struct pub_binding_t;
+/**
+ * A "dispatch connector" is a view of the dispatcher that a subsystem
+ * uses while initializing itself.  It is specific to the subsystem, and
+ * ensures that each subsystem doesn't need to identify itself
+ * repeatedly while registering its messages.
+ **/
+typedef struct pubsub_connector_t pubsub_connector_t;
+
+int pubsub_add_pub_(struct pubsub_connector_t *con,
+                    struct pub_binding_t *out,
+                    channel_id_t channel,
+                    message_id_t msg,
+                    msg_type_id_t type,
+                    unsigned flags,
+                    const char *file,
+                    unsigned line);
+
+int pubsub_add_sub_(struct pubsub_connector_t *con,
+                    recv_fn_t recv_fn,
+                    channel_id_t channel,
+                    message_id_t msg,
+                    msg_type_id_t type,
+                    unsigned flags,
+                    const char *file,
+                    unsigned line);
+
+int pubsub_connector_register_type_(struct pubsub_connector_t *,
+                                    msg_type_id_t,
+                                    dispatch_typefns_t *,
+                                    const char *file,
+                                    unsigned line);
+
+#endif /* !defined(TOR_PUBSUB_CONNECT_H) */
diff --git a/src/lib/pubsub/pubsub_flags.h b/src/lib/pubsub/pubsub_flags.h
new file mode 100644
index 000000000..53c6e4956
--- /dev/null
+++ b/src/lib/pubsub/pubsub_flags.h
@@ -0,0 +1,32 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file pubsub_flags.h
+ * @brief Flags that can be set on publish/subscribe messages.
+ **/
+
+#ifndef TOR_PUBSUB_FLAGS_H
+#define TOR_PUBSUB_FLAGS_H
+
+/**
+ * Flag for registering a message: declare that no other module is allowed to
+ * publish this message if we are publishing it, or subscribe to it if we are
+ * subscribing to it.
+ */
+#define DISP_FLAG_EXCL (1u<<0)
+
+/**
+ * Flag for registering a message: declare that this message is a stub, and we
+ * will not actually publish/subscribe it, but that the dispatcher should
+ * treat us as if we did when typechecking.
+ *
+ * We use this so that messages aren't treated as "dangling" if they are
+ * potentially used by some other build of Tor.
+ */
+#define DISP_FLAG_STUB (1u<<1)
+
+#endif /* !defined(TOR_PUBSUB_FLAGS_H) */
diff --git a/src/lib/pubsub/pubsub_macros.h b/src/lib/pubsub/pubsub_macros.h
new file mode 100644
index 000000000..357e59fd5
--- /dev/null
+++ b/src/lib/pubsub/pubsub_macros.h
@@ -0,0 +1,373 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file pubsub_macros.h
+ * \brief Macros to help with the publish/subscribe dispatch API.
+ *
+ * The dispatch API allows different subsystems of Tor to communicate with
+ * another asynchronously via a shared "message" system.  Some subsystems
+ * declare that they publish a given message, and others declare that they
+ * subscribe to it.  Both subsystems depend on the message, but not upon one
+ * another.
+ *
+ * To declare a message, use DECLARE_MESSAGE() (for messages that take their
+ * data as a pointer) or DECLARE_MESSAGE_INT() (for messages that take their
+ * data as an integer.  For example, you might say
+ *
+ *     DECLARE_MESSAGE(new_circuit, circ, circuit_handle_t *);
+ * or
+ *     DECLARE_MESSAGE_INT(shutdown_requested, boolean, bool);
+ *
+ * Every message has a unique name, a "type name" that the dispatch system
+ * uses to manage associated data, and a C type name.  You'll want to put
+ * these declarations in a header, to be included by all publishers and all
+ * subscribers.
+ *
+ * When a subsystem wants to publish a message, it uses DECLARE_PUBLISH() at
+ * file scope to create necessary static functions.  Then, in its subsystem
+ * initialization (in the "bind to dispatcher" callback) (TODO: name this
+ * properly!), it calls DISPATCH_ADD_PUB() to tell the dispatcher about its
+ * intent to publish.  When it actually wants to publish, it uses the
+ * PUBLISH() macro.  For example:
+ *
+ *     // At file scope
+ *     DECLARE_PUBLISH(shutdown_requested);
+ *
+ *     static void bind_to_dispatcher(pubsub_connector_t *con)
+ *     {
+ *         DISPATCH_ADD_PUB(con, mainchannel, shutdown_requested);
+ *     }
+ *
+ *     // somewhere in a function
+ *        {
+ *            PUBLISH(shutdown_requested, true);
+ *        }
+ *
+ * When a subsystem wants to subscribe to a message, it uses
+ * DECLARE_SUBSCRIBE() at file scope to declare static functions.  It must
+ * declare a hook function that receives the message type.  Then, in its "bind
+ * to dispatcher" function, it calls DISPATCHER_ADD_SUB() to tell the
+ * dispatcher about its intent to subscribe.  When another module publishes
+ * the message, the dispatcher will call the provided hook function.
+ *
+ *     // At file scope.  The first argument is the message that you're
+ *     // subscribing to; the second argument is the hook function to declare.
+ *     DECLARE_SUBSCRIBE(shutdown_requested, on_shutdown_req_cb);
+ *
+ *     // You need to declare this function.
+ *     static void on_shutdown_req_cb(const msg_t *msg,
+ *                                    bool value)
+ *     {
+ *         // (do something here.)
+ *     }
+ *
+ *     static void bind_to_dispatcher(pubsub_connector_t *con)
+ *     {
+ *         DISPATCH_ADD_SUB(con, mainchannel, shutdown_requested);
+ *     }
+ *
+ * Where did these types come from?  Somewhere in the code, you need to call
+ * DISPATCH_REGISTER_TYPE() to make sure that the dispatcher can manage the
+ * message auxiliary data.  It associates a vtbl-like structure with the
+ * type name, so that the dispatcher knows how to manipulate the type you're
+ * giving it.
+ *
+ * For example, the "boolean" type we're using above could be defined as:
+ *
+ *    static char *boolean_fmt(msg_aux_data_t d)
+ *    {
+ *        // This is used for debugging and dumping messages.
+ *        if (d.u64)
+ *            return tor_strdup("true");
+ *        else
+ *            return tor_strdup("false");
+ *    }
+ *
+ *    static void boolean_free(msg_aux_data_t d)
+ *    {
+ *        // We don't actually need to do anything to free a boolean.
+ *        // We could use "NULL" instead of this function, but I'm including
+ *        // it as an example.
+ *    }
+ *
+ *    static void bind_to_dispatcher(pubsub_connector_t *con)
+ *    {
+ *        dispatch_typefns_t boolean_fns = {
+ *            .fmt_fn = boolean_fmt,
+ *            .free_fn = boolean_free,
+ *        };
+ *        DISPATCH_REGISTER_TYPE(con, boolean, &boolean_fns);
+ *    }
+ *
+ *
+ *
+ * So, how does this all work?  (You can stop reading here, unless you're
+ * debugging something.)
+ *
+ * When you declare a message in a header with DECLARE_MESSAGE() or
+ * DECLARE_MESSAGE_INT(), it creates five things:
+ *
+ *    * two typedefs for the message argument (constant and non-constant
+ *      variants).
+ *    * a constant string to hold the declared message type name
+ *    * two inline functions, to coerce the message argument type to and from
+ *      a "msg_aux_data_t" union.
+ *
+ * All of these declarations have names based on the message name.
+ *
+ * Later, when you say DECLARE_PUBLISH() or DECLARE_SUBSCRIBE(), we use the
+ * elements defined by DECLARE_MESSAGE() to make sure that the publish
+ * function takes the correct argument type, and that the subscription hook is
+ * declared with the right argument type.
+ **/
+
+#ifndef TOR_DISPATCH_MSG_H
+#define TOR_DISPATCH_MSG_H
+
+#include "lib/cc/compat_compiler.h"
+#include "lib/dispatch/dispatch_naming.h"
+#include "lib/pubsub/pub_binding_st.h"
+#include "lib/pubsub/pubsub_connect.h"
+#include "lib/pubsub/pubsub_flags.h"
+#include "lib/pubsub/pubsub_publish.h"
+
+/* Implemenation notes:
+ *
+ * For a messagename "foo", the DECLARE_MESSAGE*() macros must declare:
+ *
+ * msg_arg_type__foo -- a typedef for the argument type of the foo message.
+ * msg_arg_consttype__foo -- a typedef for the const argument type of the
+ *     foo message.
+ * msg_arg_name__foo[] -- a static string constant holding the unique
+ *      identifier for the type of the foo message.
+ * msg_arg_get__foo() -- an inline function taking a msg_aux_data_t and
+ *      returning the C data type.
+ * msg_arg_set__foo() -- an inline function taking a msg_aux_data_t and
+ *      the C type, setting the msg_aux_data_t to hold the C type.
+ *
+ * For a messagename "foo", the DECLARE_PUBLISH() macro must declare:
+ *
+ * pub_binding__foo -- A static pub_binding_t object used to send messages
+ *      from this module.
+ * publish_fn__foo -- A function taking an argument of the appropriate
+ *      C type, to be invoked by PUBLISH().
+ *
+ * For a messagename "foo", the DECLARE_SUBSCRIBE() macro must declare:
+ *
+ * hookfn -- A user-provided function name, with the correct signature.
+ * recv_fn__foo -- A wrapper callback that takes a msg_t *, and calls
+ *      hookfn with the appropriate arguments.
+ */
+
+/* Macro to declare common elements shared by DECLARE_MESSAGE and
+ * DECLARE_MESSAGE_INT.  Don't call this directly.
+ *
+ * Note that the "msg_arg_name" string constant is defined in each
+ * translation unit.  This might be undesirable; we can tweak it in the
+ * future if need be.
+ */
+#define DECLARE_MESSAGE_COMMON__(messagename, typename, c_type)         \
+  typedef c_type msg_arg_type__ ##messagename;                          \
+  typedef const c_type msg_arg_consttype__ ##messagename;               \
+  ATTR_UNUSED static const char msg_arg_name__ ##messagename[] = # typename;
+
+/**
+ * Use this macro in a header to declare the existence of a given message,
+ * taking a pointer as auxiliary data.
+ *
+ * "messagename" is a unique identifier for the message; it must be a valid
+ * C identifier.
+ *
+ * "typename" is a unique identifier for the type of the auxiliary data.
+ * It needs to be defined somewhere in Tor, using
+ * "DISPATCH_REGISTER_TYPE."
+ *
+ * "c_ptr_type" is a C pointer type (like "char *" or "struct foo *").
+ * The "*" needs to be included.
+ */
+#define DECLARE_MESSAGE(messagename, typename, c_ptr_type)              \
+  DECLARE_MESSAGE_COMMON__(messagename, typename, c_ptr_type)           \
+  ATTR_UNUSED static inline c_ptr_type                                  \
+  msg_arg_get__ ##messagename(msg_aux_data_t m)                         \
+  {                                                                     \
+    return m.ptr;                                                       \
+  }                                                                     \
+  ATTR_UNUSED static inline void                                        \
+  msg_arg_set__ ##messagename(msg_aux_data_t *m, c_ptr_type v)          \
+  {                                                                     \
+    m->ptr = v;                                                         \
+  }                                                                     \
+  EAT_SEMICOLON
+
+/**
+ * Use this macro in a header to declare the existence of a given message,
+ * taking an integer as auxiliary data.
+ *
+ * "messagename" is a unique identifier for the message; it must be a valid
+ * C identifier.
+ *
+ * "typename" is a unique identifier for the type of the auxiliary data.  It
+ * needs to be defined somewhere in Tor, using "DISPATCH_REGISTER_TYPE."
+ *
+ * "c_type" is a C integer type, like "int" or "bool".  It needs to fit inside
+ * a uint64_t.
+ */
+#define DECLARE_MESSAGE_INT(messagename, typename, c_type)              \
+  DECLARE_MESSAGE_COMMON__(messagename, typename, c_type)               \
+  ATTR_UNUSED static inline c_type                                      \
+  msg_arg_get__ ##messagename(msg_aux_data_t m)                         \
+  {                                                                     \
+    return (c_type)m.u64;                                               \
+  }                                                                     \
+  ATTR_UNUSED static inline void                                        \
+  msg_arg_set__ ##messagename(msg_aux_data_t *m, c_type v)              \
+  {                                                                     \
+    m->u64 = (uint64_t)v;                                               \
+  }                                                                     \
+  EAT_SEMICOLON
+
+/**
+ * Use this macro inside a C module declare that we'll be publishing a given
+ * message type from within this module.
+ *
+ * It creates necessary functions and wrappers to publish a message whose
+ * unique identifier is "messagename".
+ *
+ * Before you use this, you need to include the header where DECLARE_MESSAGE*()
+ * was used for this message.
+ *
+ * You can only use this once per message in each subsystem.
+ */
+#define DECLARE_PUBLISH(messagename)                                    \
+  static pub_binding_t pub_binding__ ##messagename;                     \
+  static void                                                           \
+  publish_fn__ ##messagename(msg_arg_type__ ##messagename arg)          \
+  {                                                                     \
+    msg_aux_data_t data;                                                \
+    msg_arg_set__ ##messagename(&data, arg);                            \
+    pubsub_pub_(&pub_binding__ ##messagename, data);                    \
+  }                                                                     \
+  EAT_SEMICOLON
+
+/**
+ * Use this macro inside a C file to declare that we're subscribing to a
+ * given message and associating it with a given "hook function".  It
+ * declares the hook function static, and helps with strong typing.
+ *
+ * Before you use this, you need to include the header where
+ * DECLARE_MESSAGE*() was used for the message whose unique identifier is
+ * "messagename".
+ *
+ * You will need to define a function with the name that you provide for
+ * "hookfn".  The type of this function will be:
+ *     static void hookfn(const msg_t *, const c_type)
+ * where c_type is the c type that you declared in the header.
+ *
+ * You can only use this once per message in each subsystem.
+ */
+#define DECLARE_SUBSCRIBE(messagename, hookfn) \
+  static void hookfn(const msg_t *,                             \
+                     const msg_arg_consttype__ ##messagename);  \
+  static void recv_fn__ ## messagename(const msg_t *m)          \
+  {                                                             \
+    msg_arg_type__ ## messagename arg;                          \
+    arg = msg_arg_get__ ##messagename(m->aux_data__);           \
+    hookfn(m, arg);                                             \
+  }                                                             \
+  EAT_SEMICOLON
+
+/**
+ * Add a fake use of the publish function for 'messagename', so that
+ * the compiler does not call it unused.
+ */
+#define DISPATCH__FAKE_USE_OF_PUBFN_(messagename)                       \
+  ( 0 ? (publish_fn__ ##messagename((msg_arg_type__##messagename)0), 1) \
+    : 1)
+
+/*
+ * This macro is for internal use.  It backs DISPATCH_ADD_PUB*()
+ */
+#define DISPATCH_ADD_PUB_(connector, channel, messagename, flags)       \
+  (                                                                     \
+    DISPATCH__FAKE_USE_OF_PUBFN_(messagename),                          \
+    pubsub_add_pub_((connector),                                        \
+                      &pub_binding__ ##messagename,                     \
+                      get_channel_id(# channel),                        \
+                    get_message_id(# messagename),                      \
+                      get_msg_type_id(msg_arg_name__ ## messagename),   \
+                      (flags),                                          \
+                      __FILE__,                                         \
+                      __LINE__)                                         \
+    )
+
+/**
+ * Use a given connector and channel name to declare that this subsystem will
+ * publish a given message type.
+ *
+ * Call this macro from within the add_subscriptions() function of a module.
+ */
+#define DISPATCH_ADD_PUB(connector, channel, messagename)       \
+    DISPATCH_ADD_PUB_(connector, channel, messagename, 0)
+
+/**
+ * Use a given connector and channel name to declare that this subsystem will
+ * publish a given message type, and that no other subsystem is allowed to.
+ *
+ * Call this macro from within the add_subscriptions() function of a module.
+ */
+#define DISPATCH_ADD_PUB_EXCL(connector, channel, messagename)  \
+    DISPATCH_ADD_PUB_(connector, channel, messagename, DISP_FLAG_EXCL)
+
+/*
+ * This macro is for internal use. It backs DISPATCH_ADD_SUB*()
+ */
+#define DISPATCH_ADD_SUB_(connector, channel, messagename, flags)       \
+  pubsub_add_sub_((connector),                                          \
+                    recv_fn__ ##messagename,                            \
+                    get_channel_id(#channel),                           \
+                    get_message_id(# messagename),                      \
+                    get_msg_type_id(msg_arg_name__ ##messagename),      \
+                    (flags),                                            \
+                    __FILE__,                                           \
+                    __LINE__)
+/*
+ * Use a given connector and channel name to declare that this subsystem will
+ * receive a given message type.
+ *
+ * Call this macro from within the add_subscriptions() function of a module.
+ */
+#define DISPATCH_ADD_SUB(connector, channel, messagename)       \
+    DISPATCH_ADD_SUB_(connector, channel, messagename, 0)
+/**
+ * Use a given connector and channel name to declare that this subsystem will
+ * receive a given message type, and that no other subsystem is allowed to do
+ * so.
+ *
+ * Call this macro from within the add_subscriptions() function of a module.
+ */
+#define DISPATCH_ADD_SUB_EXCL(connector, channel, messagename)  \
+    DISPATCH_ADD_SUB_(connector, channel, messagename, DISP_FLAG_EXCL)
+
+/**
+ * Publish a given message with a given argument.  (Takes ownership of the
+ * argument if it is a pointer.)
+ */
+#define PUBLISH(messagename, arg)               \
+  publish_fn__ ##messagename(arg)
+
+/**
+ * Use a given connector to declare that the functions to be used to manipuate
+ * a certain C type.
+ **/
+#define DISPATCH_REGISTER_TYPE(con, type, fns)                  \
+  pubsub_connector_register_type_((con),                        \
+                                  get_msg_type_id(#type),       \
+                                  (fns),                        \
+                                  __FILE__,                     \
+                                  __LINE__)
+
+#endif /* !defined(TOR_DISPATCH_MSG_H) */
diff --git a/src/lib/pubsub/pubsub_publish.c b/src/lib/pubsub/pubsub_publish.c
new file mode 100644
index 000000000..454a335a7
--- /dev/null
+++ b/src/lib/pubsub/pubsub_publish.c
@@ -0,0 +1,72 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file pubsub_publish.c
+ * @brief Header for functions to publish using a pub_binding_t.
+ **/
+
+#define PUBSUB_PRIVATE
+#define DISPATCH_PRIVATE
+#include "orconfig.h"
+
+#include "lib/dispatch/dispatch.h"
+#include "lib/dispatch/dispatch_st.h"
+
+#include "lib/pubsub/pub_binding_st.h"
+#include "lib/pubsub/pubsub_publish.h"
+
+#include "lib/malloc/malloc.h"
+#include "lib/log/util_bug.h"
+
+#include <string.h>
+
+/**
+ * Publish a message from the publication binding <b>pub</b> using the
+ * auxiliary data <b>auxdata</b>.
+ *
+ * Return 0 on success, -1 on failure.
+ **/
+int
+pubsub_pub_(const pub_binding_t *pub, msg_aux_data_t auxdata)
+{
+  dispatch_t *d = pub->dispatch_ptr;
+  if (BUG(! d)) {
+    /* Tried to publish a message before the dispatcher was configured. */
+    /* (Without a dispatcher, we don't know how to free auxdata.) */
+    return -1;
+  }
+
+  if (BUG(pub->msg_template.type >= d->n_types)) {
+    /* The type associated with this message is not known to the dispatcher. */
+    /* (Without a correct type, we don't know how to free auxdata.) */
+    return -1;
+  }
+
+  if (BUG(pub->msg_template.msg >= d->n_msgs) ||
+      BUG(pub->msg_template.channel >= d->n_queues)) {
+    /* The message ID or channel ID was out of bounds. */
+    // LCOV_EXCL_START
+    d->typefns[pub->msg_template.type].free_fn(auxdata);
+    return -1;
+    // LCOV_EXCL_STOP
+  }
+
+  if (! d->table[pub->msg_template.msg]) {
+    /* Fast path: nobody wants this data. */
+
+    // XXXX Faster path: we could store this in the pub_binding_t.
+    d->typefns[pub->msg_template.type].free_fn(auxdata);
+    return 0;
+  }
+
+  /* Construct the message object */
+  msg_t *m = tor_malloc(sizeof(msg_t));
+  memcpy(m, &pub->msg_template, sizeof(msg_t));
+  m->aux_data__ = auxdata;
+
+  return dispatch_send_msg_unchecked(d, m);
+}
diff --git a/src/lib/pubsub/pubsub_publish.h b/src/lib/pubsub/pubsub_publish.h
new file mode 100644
index 000000000..0686a465d
--- /dev/null
+++ b/src/lib/pubsub/pubsub_publish.h
@@ -0,0 +1,15 @@
+/* Copyright (c) 2001, Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_PUBSUB_PUBLISH_H
+#define TOR_PUBSUB_PUBLISH_H
+
+#include "lib/dispatch/msgtypes.h"
+struct pub_binding_t;
+
+int pubsub_pub_(const struct pub_binding_t *pub, msg_aux_data_t auxdata);
+
+#endif /* !defined(TOR_PUBSUB_PUBLISH_H) */
diff --git a/src/lib/sandbox/include.am b/src/lib/sandbox/include.am
index adfda6bde..e81f14b55 100644
--- a/src/lib/sandbox/include.am
+++ b/src/lib/sandbox/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-sandbox-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_sandbox_a_SOURCES =			\
 	src/lib/sandbox/sandbox.c
 
@@ -13,6 +14,7 @@ src_lib_libtor_sandbox_testing_a_SOURCES = \
 src_lib_libtor_sandbox_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_sandbox_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/sandbox/linux_syscalls.inc		\
 	src/lib/sandbox/sandbox.h
diff --git a/src/lib/smartlist_core/include.am b/src/lib/smartlist_core/include.am
index 99d65f0b2..548179bc4 100644
--- a/src/lib/smartlist_core/include.am
+++ b/src/lib/smartlist_core/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-smartlist-core-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_smartlist_core_a_SOURCES =			\
 	src/lib/smartlist_core/smartlist_core.c                 \
 	src/lib/smartlist_core/smartlist_split.c
@@ -15,6 +16,7 @@ src_lib_libtor_smartlist_core_testing_a_CPPFLAGS = \
 	$(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_smartlist_core_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/smartlist_core/smartlist_core.h         \
 	src/lib/smartlist_core/smartlist_foreach.h      \
diff --git a/src/lib/smartlist_core/smartlist_core.c b/src/lib/smartlist_core/smartlist_core.c
index ac85a6cc8..6b0a305a9 100644
--- a/src/lib/smartlist_core/smartlist_core.c
+++ b/src/lib/smartlist_core/smartlist_core.c
@@ -88,6 +88,30 @@ smartlist_ensure_capacity(smartlist_t *sl, size_t size)
 #undef MAX_CAPACITY
 }
 
+/** Expand <b>sl</b> so that its length is at least <b>new_size</b>,
+ * filling in previously unused entries with NULL>
+ *
+ * Do nothing if <b>sl</b> already had at least <b>new_size</b> elements.
+ */
+void
+smartlist_grow(smartlist_t *sl, size_t new_size)
+{
+  smartlist_ensure_capacity(sl, new_size);
+
+  if (new_size > (size_t)sl->num_used) {
+    /* This memset() should be a no-op: everything else in the smartlist code
+     * tries to make sure that unused entries are always NULL.  Still, that is
+     * meant as a safety mechanism, so let's clear the memory here.
+     */
+    memset(sl->list + sl->num_used, 0,
+           sizeof(void *) * (new_size - sl->num_used));
+
+    /* This cast is safe, since we already asserted that we were below
+     * MAX_CAPACITY in smartlist_ensure_capacity(). */
+    sl->num_used = (int)new_size;
+  }
+}
+
 /** Append element to the end of the list. */
 void
 smartlist_add(smartlist_t *sl, void *element)
@@ -153,6 +177,8 @@ smartlist_remove_keeporder(smartlist_t *sl, const void *element)
       sl->list[i++] = sl->list[j];
     }
   }
+  memset(sl->list + sl->num_used, 0,
+         sizeof(void *) * (num_used_orig - sl->num_used));
 }
 
 /** If <b>sl</b> is nonempty, remove and return the final element.  Otherwise,
diff --git a/src/lib/smartlist_core/smartlist_core.h b/src/lib/smartlist_core/smartlist_core.h
index a7fbaa099..795741c44 100644
--- a/src/lib/smartlist_core/smartlist_core.h
+++ b/src/lib/smartlist_core/smartlist_core.h
@@ -43,6 +43,7 @@ void smartlist_clear(smartlist_t *sl);
 void smartlist_add(smartlist_t *sl, void *element);
 void smartlist_add_all(smartlist_t *sl, const smartlist_t *s2);
 void smartlist_add_strdup(struct smartlist_t *sl, const char *string);
+void smartlist_grow(smartlist_t *sl, size_t new_size);
 
 void smartlist_remove(smartlist_t *sl, const void *element);
 void smartlist_remove_keeporder(smartlist_t *sl, const void *element);
@@ -97,4 +98,4 @@ void smartlist_del(smartlist_t *sl, int idx);
 void smartlist_del_keeporder(smartlist_t *sl, int idx);
 void smartlist_insert(smartlist_t *sl, int idx, void *val);
 
-#endif /* !defined(TOR_CONTAINER_H) */
+#endif /* !defined(TOR_SMARTLIST_CORE_H) */
diff --git a/src/lib/smartlist_core/smartlist_split.h b/src/lib/smartlist_core/smartlist_split.h
index 4f7237612..e2cc7245b 100644
--- a/src/lib/smartlist_core/smartlist_split.h
+++ b/src/lib/smartlist_core/smartlist_split.h
@@ -17,4 +17,4 @@
 int smartlist_split_string(smartlist_t *sl, const char *str, const char *sep,
                            int flags, int max);
 
-#endif
+#endif /* !defined(TOR_SMARTLIST_SPLIT_H) */
diff --git a/src/lib/string/compat_string.h b/src/lib/string/compat_string.h
index a0e37bb6d..4f30bf539 100644
--- a/src/lib/string/compat_string.h
+++ b/src/lib/string/compat_string.h
@@ -25,14 +25,14 @@ static inline int strncasecmp(const char *a, const char *b, size_t n);
 static inline int strncasecmp(const char *a, const char *b, size_t n) {
   return _strnicmp(a,b,n);
 }
-#endif
+#endif /* !defined(HAVE_STRNCASECMP) */
 #ifndef HAVE_STRCASECMP
 static inline int strcasecmp(const char *a, const char *b);
 static inline int strcasecmp(const char *a, const char *b) {
   return _stricmp(a,b);
 }
-#endif
-#endif
+#endif /* !defined(HAVE_STRCASECMP) */
+#endif /* defined(_WIN32) */
 
 #if defined __APPLE__
 /* On OSX 10.9 and later, the overlap-checking code for strlcat would
@@ -59,4 +59,4 @@ char *tor_strtok_r_impl(char *str, const char *sep, char **lasts);
 #define tor_strtok_r(str, sep, lasts) tor_strtok_r_impl(str, sep, lasts)
 #endif
 
-#endif
+#endif /* !defined(TOR_COMPAT_STRING_H) */
diff --git a/src/lib/string/include.am b/src/lib/string/include.am
index edd74b8a3..82d35cc5a 100644
--- a/src/lib/string/include.am
+++ b/src/lib/string/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-string-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_string_a_SOURCES =			\
 	src/lib/string/compat_ctype.c			\
 	src/lib/string/compat_string.c			\
@@ -18,6 +19,7 @@ src_lib_libtor_string_testing_a_SOURCES = \
 src_lib_libtor_string_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_string_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/string/compat_ctype.h			\
 	src/lib/string/compat_string.h			\
diff --git a/src/lib/string/parse_int.h b/src/lib/string/parse_int.h
index 925547942..50d48b44c 100644
--- a/src/lib/string/parse_int.h
+++ b/src/lib/string/parse_int.h
@@ -22,4 +22,4 @@ double tor_parse_double(const char *s, double min, double max, int *ok,
 uint64_t tor_parse_uint64(const char *s, int base, uint64_t min,
                          uint64_t max, int *ok, char **next);
 
-#endif
+#endif /* !defined(TOR_PARSE_INT_H) */
diff --git a/src/lib/string/printf.c b/src/lib/string/printf.c
index 415d4ac4a..26203932e 100644
--- a/src/lib/string/printf.c
+++ b/src/lib/string/printf.c
@@ -117,8 +117,8 @@ tor_vasprintf(char **strp, const char *fmt, va_list args)
     *strp = NULL;
     return -1;
   }
-  strp_tmp = tor_malloc(len + 1);
-  r = _vsnprintf(strp_tmp, len+1, fmt, args);
+  strp_tmp = tor_malloc((size_t)len + 1);
+  r = _vsnprintf(strp_tmp, (size_t)len+1, fmt, args);
   if (r != len) {
     tor_free(strp_tmp);
     *strp = NULL;
@@ -131,21 +131,31 @@ tor_vasprintf(char **strp, const char *fmt, va_list args)
    * characters we need.  We give it a try on a short buffer first, since
    * it might be nice to avoid the second vsnprintf call.
    */
+  /* XXXX This code spent a number of years broken (see bug 30651). It is
+   * possible that no Tor users actually run on systems without vasprintf() or
+   * _vscprintf(). If so, we should consider removing this code. */
   char buf[128];
   int len, r;
   va_list tmp_args;
   va_copy(tmp_args, args);
-  /* vsnprintf() was properly checked but tor_vsnprintf() available so
-   * why not use it? */
-  len = tor_vsnprintf(buf, sizeof(buf), fmt, tmp_args);
+  /* Use vsnprintf to retrieve needed length.  tor_vsnprintf() is not an
+   * option here because it will simply return -1 if buf is not large enough
+   * to hold the complete string.
+   */
+  len = vsnprintf(buf, sizeof(buf), fmt, tmp_args);
   va_end(tmp_args);
+  buf[sizeof(buf) - 1] = '\0';
+  if (len < 0) {
+    *strp = NULL;
+    return -1;
+  }
   if (len < (int)sizeof(buf)) {
     *strp = tor_strdup(buf);
     return len;
   }
-  strp_tmp = tor_malloc(len+1);
+  strp_tmp = tor_malloc((size_t)len+1);
   /* use of tor_vsnprintf() will ensure string is null terminated */
-  r = tor_vsnprintf(strp_tmp, len+1, fmt, args);
+  r = tor_vsnprintf(strp_tmp, (size_t)len+1, fmt, args);
   if (r != len) {
     tor_free(strp_tmp);
     *strp = NULL;
diff --git a/src/lib/string/printf.h b/src/lib/string/printf.h
index 2cc13d6be..6e90770f8 100644
--- a/src/lib/string/printf.h
+++ b/src/lib/string/printf.h
@@ -27,4 +27,4 @@ int tor_asprintf(char **strp, const char *fmt, ...)
 int tor_vasprintf(char **strp, const char *fmt, va_list args)
   CHECK_PRINTF(2,0);
 
-#endif /* !defined(TOR_UTIL_STRING_H) */
+#endif /* !defined(TOR_UTIL_PRINTF_H) */
diff --git a/src/lib/string/scanf.h b/src/lib/string/scanf.h
index 6673173de..b642e242d 100644
--- a/src/lib/string/scanf.h
+++ b/src/lib/string/scanf.h
@@ -21,4 +21,4 @@ int tor_vsscanf(const char *buf, const char *pattern, va_list ap) \
 int tor_sscanf(const char *buf, const char *pattern, ...)
   CHECK_SCANF(2, 3);
 
-#endif /* !defined(TOR_UTIL_STRING_H) */
+#endif /* !defined(TOR_UTIL_SCANF_H) */
diff --git a/src/lib/string/util_string.c b/src/lib/string/util_string.c
index 0c4e39900..f5061a11d 100644
--- a/src/lib/string/util_string.c
+++ b/src/lib/string/util_string.c
@@ -71,7 +71,7 @@ tor_memstr(const void *haystack, size_t hlen, const char *needle)
 
 /** Return true iff the 'len' bytes at 'mem' are all zero. */
 int
-tor_mem_is_zero(const char *mem, size_t len)
+fast_mem_is_zero(const char *mem, size_t len)
 {
   static const char ZERO[] = {
     0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,
@@ -95,17 +95,14 @@ tor_mem_is_zero(const char *mem, size_t len)
 int
 tor_digest_is_zero(const char *digest)
 {
-  static const uint8_t ZERO_DIGEST[] = {
-    0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0
-  };
-  return tor_memeq(digest, ZERO_DIGEST, DIGEST_LEN);
+  return safe_mem_is_zero(digest, DIGEST_LEN);
 }
 
 /** Return true iff the DIGEST256_LEN bytes in digest are all zero. */
 int
 tor_digest256_is_zero(const char *digest)
 {
-  return tor_mem_is_zero(digest, DIGEST256_LEN);
+  return safe_mem_is_zero(digest, DIGEST256_LEN);
 }
 
 /** Remove from the string <b>s</b> every character which appears in
diff --git a/src/lib/string/util_string.h b/src/lib/string/util_string.h
index da4fab159..b3c6841d4 100644
--- a/src/lib/string/util_string.h
+++ b/src/lib/string/util_string.h
@@ -20,7 +20,10 @@ const void *tor_memmem(const void *haystack, size_t hlen, const void *needle,
                        size_t nlen);
 const void *tor_memstr(const void *haystack, size_t hlen,
                        const char *needle);
-int tor_mem_is_zero(const char *mem, size_t len);
+int fast_mem_is_zero(const char *mem, size_t len);
+#define fast_digest_is_zero(d) fast_mem_is_zero((d), DIGEST_LEN)
+#define fast_digetst256_is_zero(d) fast_mem_is_zero((d), DIGEST256_LEN)
+
 int tor_digest_is_zero(const char *digest);
 int tor_digest256_is_zero(const char *digest);
 
diff --git a/src/lib/subsys/include.am b/src/lib/subsys/include.am
index 4741126b1..c9ab54ca7 100644
--- a/src/lib/subsys/include.am
+++ b/src/lib/subsys/include.am
@@ -1,3 +1,4 @@
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS += \
 	src/lib/subsys/subsys.h
diff --git a/src/lib/subsys/subsys.h b/src/lib/subsys/subsys.h
index 241ad7829..21f984f32 100644
--- a/src/lib/subsys/subsys.h
+++ b/src/lib/subsys/subsys.h
@@ -8,7 +8,7 @@
 
 #include <stdbool.h>
 
-struct dispatch_connector_t;
+struct pubsub_connector_t;
 
 /**
  * A subsystem is a part of Tor that is initialized, shut down, configured,
@@ -58,7 +58,7 @@ typedef struct subsys_fns_t {
   /**
    * Connect a subsystem to the message dispatch system.
    **/
-  int (*add_pubsub)(struct dispatch_connector_t *);
+  int (*add_pubsub)(struct pubsub_connector_t *);
 
   /**
    * Perform any necessary pre-fork cleanup.  This function may not fail.
@@ -92,4 +92,4 @@ typedef struct subsys_fns_t {
  * less than this value. */
 #define SUBSYS_LEVEL_LIBS -10
 
-#endif
+#endif /* !defined(TOR_SUBSYS_T) */
diff --git a/src/lib/term/getpass.h b/src/lib/term/getpass.h
index a9c146ea8..aa597ec42 100644
--- a/src/lib/term/getpass.h
+++ b/src/lib/term/getpass.h
@@ -15,4 +15,4 @@
 
 ssize_t tor_getpass(const char *prompt, char *output, size_t buflen);
 
-#endif
+#endif /* !defined(TOR_GETPASS_H) */
diff --git a/src/lib/term/include.am b/src/lib/term/include.am
index 55fe548eb..a120bba0c 100644
--- a/src/lib/term/include.am
+++ b/src/lib/term/include.am
@@ -11,6 +11,7 @@ else
 readpassphrase_source=
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_term_a_SOURCES =			\
 	src/lib/term/getpass.c			\
 	$(readpassphrase_source)
@@ -20,5 +21,6 @@ src_lib_libtor_term_testing_a_SOURCES = \
 src_lib_libtor_term_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_term_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/term/getpass.h
diff --git a/src/lib/testsupport/include.am b/src/lib/testsupport/include.am
index b2aa62098..a5ed46eb6 100644
--- a/src/lib/testsupport/include.am
+++ b/src/lib/testsupport/include.am
@@ -1,3 +1,4 @@
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS += \
 	src/lib/testsupport/testsupport.h
diff --git a/src/lib/testsupport/testsupport.h b/src/lib/testsupport/testsupport.h
index 9363a9ba6..631ec0228 100644
--- a/src/lib/testsupport/testsupport.h
+++ b/src/lib/testsupport/testsupport.h
@@ -21,7 +21,7 @@
  * tests. */
 #define STATIC
 #define EXTERN(type, name) extern type name;
-#else
+#else /* !(defined(TOR_UNIT_TESTS)) */
 #define STATIC static
 #define EXTERN(type, name)
 #endif /* defined(TOR_UNIT_TESTS) */
diff --git a/src/lib/thread/include.am b/src/lib/thread/include.am
index 695795a2c..cd8016b5d 100644
--- a/src/lib/thread/include.am
+++ b/src/lib/thread/include.am
@@ -12,6 +12,7 @@ if THREADS_WIN32
 threads_impl_source=src/lib/thread/compat_winthreads.c
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_thread_a_SOURCES =			\
 	src/lib/thread/compat_threads.c			\
 	src/lib/thread/numcpus.c			\
@@ -22,6 +23,7 @@ src_lib_libtor_thread_testing_a_SOURCES = \
 src_lib_libtor_thread_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_thread_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/thread/numcpus.h			\
 	src/lib/thread/thread_sys.h			\
diff --git a/src/lib/thread/numcpus.h b/src/lib/thread/numcpus.h
index 3f0a29ce7..2f1ea16eb 100644
--- a/src/lib/thread/numcpus.h
+++ b/src/lib/thread/numcpus.h
@@ -13,4 +13,4 @@
 
 int compute_num_cpus(void);
 
-#endif
+#endif /* !defined(TOR_NUMCPUS_H) */
diff --git a/src/lib/time/compat_time.c b/src/lib/time/compat_time.c
index c6625c780..3f41500f3 100644
--- a/src/lib/time/compat_time.c
+++ b/src/lib/time/compat_time.c
@@ -164,6 +164,8 @@ static int64_t last_tick_count = 0;
  * to be monotonic; increments them as appropriate so that they actually
  * _are_ monotonic.
  *
+ * The returned time may be the same as the previous returned time.
+ *
  * Caller must hold lock. */
 STATIC int64_t
 ratchet_performance_counter(int64_t count_raw)
@@ -202,6 +204,8 @@ static struct timeval timeofday_offset = { 0, 0 };
  * supposed to be monotonic; increments them as appropriate so that they
  * actually _are_ monotonic.
  *
+ * The returned time may be the same as the previous returned time.
+ *
  * Caller must hold lock. */
 STATIC void
 ratchet_timeval(const struct timeval *timeval_raw, struct timeval *out)
@@ -270,7 +274,9 @@ monotime_init_internal(void)
 }
 
 /**
- * Set "out" to the most recent monotonic time value
+ * Set "out" to the most recent monotonic time value.
+ *
+ * The returned time may be the same as the previous returned time.
  */
 void
 monotime_get(monotime_t *out)
@@ -298,10 +304,12 @@ monotime_coarse_get(monotime_coarse_t *out)
 #endif /* defined(TOR_UNIT_TESTS) */
   out->abstime_ = mach_approximate_time();
 }
-#endif
+#endif /* defined(HAVE_MACH_APPROXIMATE_TIME) */
 
 /**
  * Return the number of nanoseconds between <b>start</b> and <b>end</b>.
+ *
+ * The returned value may be equal to zero.
  */
 int64_t
 monotime_diff_nsec(const monotime_t *start,
@@ -519,7 +527,7 @@ monotime_init_internal(void)
 
   HANDLE h = load_windows_system_library(TEXT("kernel32.dll"));
   if (h) {
-    GetTickCount64_fn = (GetTickCount64_fn_t)
+    GetTickCount64_fn = (GetTickCount64_fn_t) (void(*)(void))
       GetProcAddress(h, "GetTickCount64");
   }
   // We can't call FreeLibrary(h) here, because freeing the handle may
@@ -759,7 +767,7 @@ monotime_coarse_zero(monotime_coarse_t *out)
 {
   memset(out, 0, sizeof(*out));
 }
-#endif
+#endif /* defined(MONOTIME_COARSE_TYPE_IS_DIFFERENT) */
 
 int64_t
 monotime_diff_usec(const monotime_t *start,
@@ -825,7 +833,7 @@ monotime_coarse_absolute_msec(void)
 {
   return monotime_coarse_absolute_nsec() / ONE_MILLION;
 }
-#else
+#else /* !(defined(MONOTIME_COARSE_FN_IS_DIFFERENT)) */
 #define initialized_at_coarse initialized_at
 #endif /* defined(MONOTIME_COARSE_FN_IS_DIFFERENT) */
 
@@ -857,7 +865,7 @@ monotime_msec_to_approx_coarse_stamp_units(uint64_t msec)
     mach_time_info.numer;
   return abstime_val >> monotime_shift;
 }
-#else
+#else /* !(defined(__APPLE__)) */
 uint64_t
 monotime_coarse_stamp_units_to_approx_msec(uint64_t units)
 {
@@ -868,4 +876,4 @@ monotime_msec_to_approx_coarse_stamp_units(uint64_t msec)
 {
   return (msec * STAMP_TICKS_PER_SECOND) / 1000;
 }
-#endif
+#endif /* defined(__APPLE__) */
diff --git a/src/lib/time/compat_time.h b/src/lib/time/compat_time.h
index 2cd4b3bee..8c7661d7c 100644
--- a/src/lib/time/compat_time.h
+++ b/src/lib/time/compat_time.h
@@ -15,11 +15,29 @@
  * of tens of milliseconds.
  */
 
-/* Q: Should you use monotime or monotime_coarse as your source?
+/* Q: When should I use monotonic time?
+ *
+ * A: If you need a time that never decreases, use monotonic time. If you need
+ * to send a time to a user or another process, or store a time, use the
+ * wall-clock time.
+ *
+ * Q: Should you use monotime or monotime_coarse as your source?
  *
  * A: Generally, you get better precision with monotime, but better
  * performance with monotime_coarse.
  *
+ * Q: What is a "monotonic" time, exactly?
+ *
+ * A: Monotonic times are strictly non-decreasing. The difference between any
+ * previous monotonic time, and the current monotonic time, is always greater
+ * than *or equal to* zero.
+ * Zero deltas happen more often:
+ *  - on Windows (due to an OS bug),
+ *  - when using monotime_coarse, or on systems with low-resolution timers,
+ *  - on platforms where we emulate monotonic time using wall-clock time, and
+ *  - when using time units that are larger than nanoseconds (due to
+ *    truncation on division).
+ *
  * Q: Should you use monotime_t or monotime_coarse_t directly? Should you use
  *    usec? msec? "stamp units?"
  *
@@ -95,7 +113,7 @@
  * All, "timestamp units": Cheap everywhere: it never divides.
  *
  * Q: This is only somewhat related, but how much precision could I hope for
- *    from a libevent time.?
+ *    from a libevent time?
  *
  * A: Actually, it's _very_ related if you're timing in order to have a
  * timeout happen.
@@ -182,26 +200,36 @@ void monotime_init(void);
 void monotime_get(monotime_t *out);
 /**
  * Return the number of nanoseconds between <b>start</b> and <b>end</b>.
+ * The returned value may be equal to zero.
  */
 int64_t monotime_diff_nsec(const monotime_t *start, const monotime_t *end);
 /**
  * Return the number of microseconds between <b>start</b> and <b>end</b>.
+ * The returned value may be equal to zero.
+ * Fractional units are truncated, not rounded.
  */
 int64_t monotime_diff_usec(const monotime_t *start, const monotime_t *end);
 /**
  * Return the number of milliseconds between <b>start</b> and <b>end</b>.
+ * The returned value may be equal to zero.
+ * Fractional units are truncated, not rounded.
  */
 int64_t monotime_diff_msec(const monotime_t *start, const monotime_t *end);
 /**
  * Return the number of nanoseconds since the timer system was initialized.
+ * The returned value may be equal to zero.
  */
 uint64_t monotime_absolute_nsec(void);
 /**
  * Return the number of microseconds since the timer system was initialized.
+ * The returned value may be equal to zero.
+ * Fractional units are truncated, not rounded.
  */
 MOCK_DECL(uint64_t, monotime_absolute_usec,(void));
 /**
  * Return the number of milliseconds since the timer system was initialized.
+ * The returned value may be equal to zero.
+ * Fractional units are truncated, not rounded.
  */
 uint64_t monotime_absolute_msec(void);
 
@@ -225,6 +253,9 @@ void monotime_add_msec(monotime_t *out, const monotime_t *val, uint32_t msec);
  * Set <b>out</b> to the current coarse time.
  */
 void monotime_coarse_get(monotime_coarse_t *out);
+/**
+ * Like monotime_absolute_*(), but faster on some platforms.
+ */
 uint64_t monotime_coarse_absolute_nsec(void);
 uint64_t monotime_coarse_absolute_usec(void);
 uint64_t monotime_coarse_absolute_msec(void);
@@ -248,18 +279,27 @@ uint32_t monotime_coarse_to_stamp(const monotime_coarse_t *t);
 /**
  * Convert a difference, expressed in the units of monotime_coarse_to_stamp,
  * into an approximate number of milliseconds.
+ *
+ * The returned value may be equal to zero.
+ * Fractional units are truncated, not rounded.
  */
 uint64_t monotime_coarse_stamp_units_to_approx_msec(uint64_t units);
 uint64_t monotime_msec_to_approx_coarse_stamp_units(uint64_t msec);
 uint32_t monotime_coarse_get_stamp(void);
 
 #if defined(MONOTIME_COARSE_TYPE_IS_DIFFERENT)
+/**
+ * Like monotime_diff_*(), but faster on some platforms.
+ */
 int64_t monotime_coarse_diff_nsec(const monotime_coarse_t *start,
     const monotime_coarse_t *end);
 int64_t monotime_coarse_diff_usec(const monotime_coarse_t *start,
     const monotime_coarse_t *end);
 int64_t monotime_coarse_diff_msec(const monotime_coarse_t *start,
     const monotime_coarse_t *end);
+/**
+ * Like monotime_*(), but faster on some platforms.
+ */
 void monotime_coarse_zero(monotime_coarse_t *out);
 int monotime_coarse_is_zero(const monotime_coarse_t *val);
 void monotime_coarse_add_msec(monotime_coarse_t *out,
@@ -278,6 +318,9 @@ void monotime_coarse_add_msec(monotime_coarse_t *out,
  *
  * Requires that the difference fit into an int32_t; not for use with
  * large time differences.
+ *
+ * The returned value may be equal to zero.
+ * Fractional units are truncated, not rounded.
  */
 int32_t monotime_coarse_diff_msec32_(const monotime_coarse_t *start,
                                      const monotime_coarse_t *end);
@@ -287,6 +330,9 @@ int32_t monotime_coarse_diff_msec32_(const monotime_coarse_t *start,
  *
  * Requires that the difference fit into an int32_t; not for use with
  * large time differences.
+ *
+ * The returned value may be equal to zero.
+ * Fractional units are truncated, not rounded.
  */
 static inline int32_t
 monotime_coarse_diff_msec32(const monotime_coarse_t *start,
@@ -298,7 +344,7 @@ monotime_coarse_diff_msec32(const monotime_coarse_t *start,
 #else
 #define USING_32BIT_MSEC_HACK
   return monotime_coarse_diff_msec32_(start, end);
-#endif
+#endif /* SIZEOF_VOID_P == 8 */
 }
 
 #ifdef TOR_UNIT_TESTS
diff --git a/src/lib/time/include.am b/src/lib/time/include.am
index dae16f49a..dcb199b14 100644
--- a/src/lib/time/include.am
+++ b/src/lib/time/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-time-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_time_a_SOURCES =	\
 		src/lib/time/compat_time.c	\
 		src/lib/time/time_sys.c		\
@@ -15,6 +16,7 @@ src_lib_libtor_time_testing_a_SOURCES = \
 src_lib_libtor_time_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_time_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=				\
 		src/lib/time/compat_time.h	\
 		src/lib/time/time_sys.h		\
diff --git a/src/lib/time/tvdiff.h b/src/lib/time/tvdiff.h
index 724af1528..657cb9955 100644
--- a/src/lib/time/tvdiff.h
+++ b/src/lib/time/tvdiff.h
@@ -20,4 +20,4 @@ int64_t tv_to_msec(const struct timeval *tv);
 
 time_t time_diff(const time_t from, const time_t to);
 
-#endif
+#endif /* !defined(TOR_TVDIFF_H) */
diff --git a/src/lib/tls/include.am b/src/lib/tls/include.am
index 1817739ee..7e05ef4f8 100644
--- a/src/lib/tls/include.am
+++ b/src/lib/tls/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-tls-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_tls_a_SOURCES =			\
 	src/lib/tls/buffers_tls.c		\
 	src/lib/tls/tortls.c			\
@@ -29,6 +30,7 @@ src_lib_libtor_tls_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_tls_testing_a_CFLAGS = \
 	$(AM_CFLAGS) $(TOR_CFLAGS_CRYPTLIB) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=				\
 	src/lib/tls/ciphers.inc			\
 	src/lib/tls/buffers_tls.h		\
diff --git a/src/lib/tls/nss_countbytes.h b/src/lib/tls/nss_countbytes.h
index 8b3160392..47f220c4c 100644
--- a/src/lib/tls/nss_countbytes.h
+++ b/src/lib/tls/nss_countbytes.h
@@ -22,4 +22,4 @@ int tor_get_prfiledesc_byte_counts(struct PRFileDesc *fd,
                                    uint64_t *n_read_out,
                                    uint64_t *n_written_out);
 
-#endif
+#endif /* !defined(TOR_NSS_COUNTBYTES_H) */
diff --git a/src/lib/tls/tortls.h b/src/lib/tls/tortls.h
index 8efc7a1c9..9e195c6af 100644
--- a/src/lib/tls/tortls.h
+++ b/src/lib/tls/tortls.h
@@ -25,12 +25,12 @@ struct ssl_ctx_st;
 struct ssl_session_st;
 typedef struct ssl_ctx_st tor_tls_context_impl_t;
 typedef struct ssl_st tor_tls_impl_t;
-#else
+#else /* !(defined(ENABLE_OPENSSL)) */
 struct PRFileDesc;
 typedef struct PRFileDesc tor_tls_context_impl_t;
 typedef struct PRFileDesc tor_tls_impl_t;
-#endif
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
+#endif /* defined(TORTLS_PRIVATE) */
 
 struct tor_x509_cert_t;
 
@@ -144,9 +144,9 @@ void check_no_tls_errors_(const char *fname, int line);
 
 void tor_tls_log_one_error(tor_tls_t *tls, unsigned long err,
                            int severity, int domain, const char *doing);
-#else
+#else /* !(defined(ENABLE_OPENSSL)) */
 #define check_no_tls_errors() STMT_NIL
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 int tor_tls_get_my_certs(int server,
                          const struct tor_x509_cert_t **link_cert_out,
diff --git a/src/lib/tls/tortls_internal.h b/src/lib/tls/tortls_internal.h
index 071c50656..866483a94 100644
--- a/src/lib/tls/tortls_internal.h
+++ b/src/lib/tls/tortls_internal.h
@@ -61,8 +61,8 @@ STATIC int tor_tls_session_secret_cb(struct ssl_st *ssl, void *secret,
                             void *arg);
 STATIC int find_cipher_by_id(const SSL *ssl, const SSL_METHOD *m,
                              uint16_t cipher);
-#endif
-#endif
+#endif /* defined(TORTLS_OPENSSL_PRIVATE) */
+#endif /* defined(ENABLE_OPENSSL) */
 
 #ifdef TOR_UNIT_TESTS
 extern int tor_tls_object_ex_data_index;
@@ -73,4 +73,4 @@ extern uint64_t total_bytes_written_over_tls;
 extern uint64_t total_bytes_written_by_tls;
 #endif /* defined(TOR_UNIT_TESTS) */
 
-#endif /* defined(TORTLS_INTERNAL_H) */
+#endif /* !defined(TORTLS_INTERNAL_H) */
diff --git a/src/lib/tls/tortls_openssl.c b/src/lib/tls/tortls_openssl.c
index b40f948a3..86f0ac42c 100644
--- a/src/lib/tls/tortls_openssl.c
+++ b/src/lib/tls/tortls_openssl.c
@@ -25,7 +25,7 @@
    * <winsock.h> and mess things up, in at least some openssl versions. */
   #include <winsock2.h>
   #include <ws2tcpip.h>
-#endif
+#endif /* defined(_WIN32) */
 
 #include "lib/crypt_ops/crypto_cipher.h"
 #include "lib/crypt_ops/crypto_rand.h"
@@ -318,7 +318,7 @@ tor_tls_init(void)
 #else
     SSL_library_init();
     SSL_load_error_strings();
-#endif
+#endif /* defined(OPENSSL_1_1_API) */
 
 #if (SIZEOF_VOID_P >= 8 &&                              \
      OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,0,1))
@@ -383,7 +383,7 @@ static const char SERVER_CIPHER_LIST[] =
    * conclude that it has no valid ciphers if it's running with TLS1.3.
    */
   TLS1_3_TXT_AES_128_GCM_SHA256 ":"
-#endif
+#endif /* defined(TLS1_3_TXT_AES_128_GCM_SHA256) */
   TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":"
   TLS1_TXT_DHE_RSA_WITH_AES_128_SHA;
 
@@ -657,7 +657,7 @@ tor_tls_context_new(crypto_pk_t *identity, unsigned int key_lifetime,
     if (r < 0)
       goto error;
   }
-#else
+#else /* !(defined(SSL_CTX_set1_groups_list) || ...) */
   if (! is_client) {
     int nid;
     EC_KEY *ec_key;
@@ -673,7 +673,7 @@ tor_tls_context_new(crypto_pk_t *identity, unsigned int key_lifetime,
       SSL_CTX_set_tmp_ecdh(result->ctx, ec_key);
     EC_KEY_free(ec_key);
   }
-#endif
+#endif /* defined(SSL_CTX_set1_groups_list) || ...) */
   SSL_CTX_set_verify(result->ctx, SSL_VERIFY_PEER,
                      always_accept_verify_cb);
   /* let us realloc bufs that we're writing from */
@@ -1062,7 +1062,7 @@ tor_tls_new(tor_socket_t sock, int isServer)
     /* We can't actually use TLS 1.3 until this bug is fixed. */
     SSL_set_max_proto_version(result->ssl, TLS1_2_VERSION);
   }
-#endif
+#endif /* defined(SSL_CTRL_SET_MAX_PROTO_VERSION) */
 
   if (!SSL_set_cipher_list(result->ssl,
                      isServer ? SERVER_CIPHER_LIST : CLIENT_CIPHER_LIST)) {
@@ -1728,7 +1728,7 @@ tor_tls_export_key_material,(tor_tls_t *tls, uint8_t *secrets_out,
     else
       return -1;
   }
-#endif
+#endif /* defined(TLS1_3_VERSION) */
 
   return (r == 1) ? 0 : -1;
 }
diff --git a/src/lib/tls/tortls_st.h b/src/lib/tls/tortls_st.h
index 3f7ea8ac6..73f6e6ecc 100644
--- a/src/lib/tls/tortls_st.h
+++ b/src/lib/tls/tortls_st.h
@@ -64,7 +64,7 @@ struct tor_tls_t {
   void (*negotiated_callback)(tor_tls_t *tls, void *arg);
   /** Argument to pass to negotiated_callback. */
   void *callback_arg;
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 #ifdef ENABLE_NSS
   /** Last values retried from tor_get_prfiledesc_byte_counts(). */
   uint64_t last_write_count;
@@ -72,4 +72,4 @@ struct tor_tls_t {
 #endif
 };
 
-#endif
+#endif /* !defined(TOR_TORTLS_ST_H) */
diff --git a/src/lib/tls/x509.h b/src/lib/tls/x509.h
index 5e6660de5..0390a5464 100644
--- a/src/lib/tls/x509.h
+++ b/src/lib/tls/x509.h
@@ -35,7 +35,7 @@ struct tor_x509_cert_t {
   common_digests_t cert_digests;
   common_digests_t pkey_digests;
 };
-#endif
+#endif /* defined(TOR_X509_PRIVATE) */
 
 void tor_tls_pick_certificate_lifetime(time_t now,
                                        unsigned cert_lifetime,
@@ -47,7 +47,7 @@ tor_x509_cert_t *tor_x509_cert_replace_expiration(
                                                const tor_x509_cert_t *inp,
                                                time_t new_expiration_time,
                                                crypto_pk_t *signing_key);
-#endif
+#endif /* defined(TOR_UNIT_TESTS) */
 
 tor_x509_cert_t *tor_x509_cert_dup(const tor_x509_cert_t *cert);
 
@@ -72,4 +72,4 @@ int tor_tls_cert_is_valid(int severity,
                           time_t now,
                           int check_rsa_1024);
 
-#endif
+#endif /* !defined(TOR_X509_H) */
diff --git a/src/lib/tls/x509_internal.h b/src/lib/tls/x509_internal.h
index bf2bec968..f858baae9 100644
--- a/src/lib/tls/x509_internal.h
+++ b/src/lib/tls/x509_internal.h
@@ -50,4 +50,4 @@ int tor_x509_cert_set_cached_der_encoding(tor_x509_cert_t *cert);
 #define tor_x509_cert_set_cached_der_encoding(cert) (0)
 #endif
 
-#endif
+#endif /* !defined(TOR_X509_INTERNAL_H) */
diff --git a/src/lib/tls/x509_nss.c b/src/lib/tls/x509_nss.c
index fb4af54c5..e04afaf07 100644
--- a/src/lib/tls/x509_nss.c
+++ b/src/lib/tls/x509_nss.c
@@ -120,13 +120,13 @@ tor_tls_create_certificate_internal(crypto_pk_t *rsa,
                                      der.data, der.len,
                                      (SECKEYPrivateKey *)signing_key,//const
                                      &cert->signature);
-#else
+#else /* !(0) */
   s = SEC_DerSignData(cert->arena,
                       &signed_der,
                       der.data, der.len,
                       (SECKEYPrivateKey *)signing_key,//const
                       SEC_OID_PKCS1_SHA256_WITH_RSA_ENCRYPTION);
-#endif
+#endif /* 0 */
 
   if (s != SECSuccess)
     goto err;
@@ -145,7 +145,7 @@ tor_tls_create_certificate_internal(crypto_pk_t *rsa,
                                &result_cert->signatureWrap, issuer_pk, NULL);
     tor_assert(cert_ok == SECSuccess);
   }
-#endif
+#endif /* 1 */
 
  err:
   if (subject_spki)
@@ -455,4 +455,4 @@ tor_x509_cert_replace_expiration(const tor_x509_cert_t *inp,
 
   return newcert ? tor_x509_cert_new(newcert) : NULL;
 }
-#endif
+#endif /* defined(TOR_UNIT_TESTS) */
diff --git a/src/lib/tls/x509_openssl.c b/src/lib/tls/x509_openssl.c
index a344279c2..03f65049c 100644
--- a/src/lib/tls/x509_openssl.c
+++ b/src/lib/tls/x509_openssl.c
@@ -59,12 +59,12 @@ ENABLE_GCC_WARNING(redundant-decls)
 #define X509_get_notAfter(cert) \
     X509_getm_notAfter(cert)
 #endif
-#else /* ! OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,1,0) */
+#else /* !(defined(OPENSSL_1_1_API)) */
 #define X509_get_notBefore_const(cert) \
   ((const ASN1_TIME*) X509_get_notBefore((X509 *)cert))
 #define X509_get_notAfter_const(cert) \
   ((const ASN1_TIME*) X509_get_notAfter((X509 *)cert))
-#endif
+#endif /* defined(OPENSSL_1_1_API) */
 
 /** Return a newly allocated X509 name with commonName <b>cname</b>. */
 static X509_NAME *
diff --git a/src/lib/trace/debug.h b/src/lib/trace/debug.h
index e35616cf5..92bb95c88 100644
--- a/src/lib/trace/debug.h
+++ b/src/lib/trace/debug.h
@@ -27,4 +27,4 @@
                         "\"" XSTR(subsystem) "\" hit. " \
                         "(line "XSTR(__LINE__) ")")
 
-#endif /* TOR_TRACE_LOG_DEBUG_H */
+#endif /* !defined(TOR_TRACE_LOG_DEBUG_H) */
diff --git a/src/lib/trace/events.h b/src/lib/trace/events.h
index 1e1e7b9d1..0674f7d50 100644
--- a/src/lib/trace/events.h
+++ b/src/lib/trace/events.h
@@ -34,12 +34,12 @@
 #include "lib/trace/debug.h"
 #endif
 
-#else /* TOR_EVENT_TRACING_ENABLED */
+#else /* !(defined(TOR_EVENT_TRACING_ENABLED)) */
 
 /* Reaching this point, we NOP every event declaration because event tracing
  * is not been enabled at compile time. */
 #define tor_trace(subsystem, name, args...)
 
-#endif /* TOR_EVENT_TRACING_ENABLED */
+#endif /* defined(TOR_EVENT_TRACING_ENABLED) */
 
-#endif /* TOR_TRACE_EVENTS_H */
+#endif /* !defined(TOR_TRACE_EVENTS_H) */
diff --git a/src/lib/trace/include.am b/src/lib/trace/include.am
index 6f10c9874..98098c87f 100644
--- a/src/lib/trace/include.am
+++ b/src/lib/trace/include.am
@@ -2,6 +2,7 @@
 noinst_LIBRARIES += \
 	src/lib/libtor-trace.a
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 TRACEHEADERS = \
 	src/lib/trace/trace.h \
 	src/lib/trace/events.h
@@ -11,7 +12,7 @@ TRACEHEADERS += \
 	src/lib/trace/debug.h
 endif
 
-# Library source files.
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_trace_a_SOURCES = \
 	src/lib/trace/trace.c
 
diff --git a/src/lib/trace/trace.h b/src/lib/trace/trace.h
index 606d43556..5001b28a1 100644
--- a/src/lib/trace/trace.h
+++ b/src/lib/trace/trace.h
@@ -11,4 +11,4 @@
 
 void tor_trace_init(void);
 
-#endif // TOR_TRACE_TRACE_H
+#endif /* !defined(TOR_TRACE_TRACE_H) */
diff --git a/src/lib/version/include.am b/src/lib/version/include.am
index 6944eb05e..0ae31be1b 100644
--- a/src/lib/version/include.am
+++ b/src/lib/version/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-version-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_version_a_SOURCES =			\
 	src/lib/version/git_revision.c			\
 	src/lib/version/version.c
@@ -20,6 +21,7 @@ src/lib/version/git_revision.$(OBJEXT) \
   src/lib/version/src_lib_libtor_version_testing_a-git_revision.$(OBJEXT): \
 	micro-revision.i
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/version/git_revision.h			\
 	src/lib/version/torversion.h
diff --git a/src/lib/wallclock/approx_time.h b/src/lib/wallclock/approx_time.h
index e6b53f2c2..e7da16012 100644
--- a/src/lib/wallclock/approx_time.h
+++ b/src/lib/wallclock/approx_time.h
@@ -22,4 +22,4 @@ time_t approx_time(void);
 void update_approx_time(time_t now);
 #endif /* defined(TIME_IS_FAST) */
 
-#endif
+#endif /* !defined(TOR_APPROX_TIME_H) */
diff --git a/src/lib/wallclock/include.am b/src/lib/wallclock/include.am
index 2351252e0..2b50d6ccb 100644
--- a/src/lib/wallclock/include.am
+++ b/src/lib/wallclock/include.am
@@ -5,6 +5,7 @@ if UNITTESTS_ENABLED
 noinst_LIBRARIES += src/lib/libtor-wallclock-testing.a
 endif
 
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_lib_libtor_wallclock_a_SOURCES =			\
 	src/lib/wallclock/approx_time.c			\
 	src/lib/wallclock/time_to_tm.c			\
@@ -15,6 +16,7 @@ src_lib_libtor_wallclock_testing_a_SOURCES = \
 src_lib_libtor_wallclock_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
 src_lib_libtor_wallclock_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS +=					\
 	src/lib/wallclock/approx_time.h			\
 	src/lib/wallclock/timeval.h			\
diff --git a/src/lib/wallclock/time_to_tm.h b/src/lib/wallclock/time_to_tm.h
index abe78c0ef..da27fcaba 100644
--- a/src/lib/wallclock/time_to_tm.h
+++ b/src/lib/wallclock/time_to_tm.h
@@ -19,4 +19,4 @@ struct tm *tor_localtime_r_msg(const time_t *timep, struct tm *result,
 struct tm *tor_gmtime_r_msg(const time_t *timep, struct tm *result,
                             char **err_out);
 
-#endif
+#endif /* !defined(TOR_WALLCLOCK_TIME_TO_TM_H) */
diff --git a/src/lib/wallclock/timeval.h b/src/lib/wallclock/timeval.h
index 4967e939b..e632d04a0 100644
--- a/src/lib/wallclock/timeval.h
+++ b/src/lib/wallclock/timeval.h
@@ -20,6 +20,27 @@
 #include <sys/time.h>
 #endif
 
+#ifdef TOR_COVERAGE
+/* For coverage builds, we use a slower definition of these macros without
+ * branches, to make coverage consistent. */
+#undef timeradd
+#undef timersub
+#define timeradd(tv1,tv2,tvout) \
+  do {                          \
+    (tvout)->tv_sec = (tv1)->tv_sec + (tv2)->tv_sec;    \
+    (tvout)->tv_usec = (tv1)->tv_usec + (tv2)->tv_usec; \
+    (tvout)->tv_sec += (tvout)->tv_usec / 1000000;      \
+    (tvout)->tv_usec %= 1000000;                        \
+  } while (0)
+#define timersub(tv1,tv2,tvout) \
+  do {                          \
+    (tvout)->tv_sec = (tv1)->tv_sec - (tv2)->tv_sec - 1;            \
+    (tvout)->tv_usec = (tv1)->tv_usec - (tv2)->tv_usec + 1000000;   \
+    (tvout)->tv_sec += (tvout)->tv_usec / 1000000;                  \
+    (tvout)->tv_usec %= 1000000;                                    \
+  } while (0)
+#endif /* defined(TOR_COVERAGE) */
+
 #ifndef timeradd
 /** Replacement for timeradd on platforms that do not have it: sets tvout to
  * the sum of tv1 and tv2. */
@@ -62,4 +83,4 @@
    ((tv1)->tv_sec op (tv2)->tv_sec))
 #endif /* !defined(timercmp) */
 
-#endif
+#endif /* !defined(TOR_TIMEVAL_H) */
diff --git a/src/lib/wallclock/tor_gettimeofday.h b/src/lib/wallclock/tor_gettimeofday.h
index c7fff9747..6fec2fc89 100644
--- a/src/lib/wallclock/tor_gettimeofday.h
+++ b/src/lib/wallclock/tor_gettimeofday.h
@@ -17,4 +17,4 @@ struct timeval;
 
 MOCK_DECL(void, tor_gettimeofday, (struct timeval *timeval));
 
-#endif
+#endif /* !defined(TOR_GETTIMEOFDAY_H) */
diff --git a/src/rust/protover/ffi.rs b/src/rust/protover/ffi.rs
index 066b08edd..14170d035 100644
--- a/src/rust/protover/ffi.rs
+++ b/src/rust/protover/ffi.rs
@@ -31,6 +31,7 @@ fn translate_to_rust(c_proto: uint32_t) -> Result<Protocol, ProtoverError> {
         8 => Ok(Protocol::Microdesc),
         9 => Ok(Protocol::Cons),
         10 => Ok(Protocol::Padding),
+        11 => Ok(Protocol::FlowCtrl),
         _ => Err(ProtoverError::UnknownProtocol),
     }
 }
diff --git a/src/rust/protover/protover.rs b/src/rust/protover/protover.rs
index 74158d9f6..7a76fcdd9 100644
--- a/src/rust/protover/protover.rs
+++ b/src/rust/protover/protover.rs
@@ -47,6 +47,7 @@ pub enum Protocol {
     Microdesc,
     Relay,
     Padding,
+    FlowCtrl,
 }
 
 impl fmt::Display for Protocol {
@@ -75,6 +76,7 @@ impl FromStr for Protocol {
             "Microdesc" => Ok(Protocol::Microdesc),
             "Relay" => Ok(Protocol::Relay),
             "Padding" => Ok(Protocol::Padding),
+            "FlowCtrl" => Ok(Protocol::FlowCtrl),
             _ => Err(ProtoverError::UnknownProtocol),
         }
     }
@@ -166,7 +168,8 @@ pub(crate) fn get_supported_protocols_cstr() -> &'static CStr {
              LinkAuth=3 \
              Microdesc=1-2 \
              Relay=1-2 \
-             Padding=1"
+             Padding=2 \
+             FlowCtrl=1"
         )
     } else {
         cstr!(
@@ -180,7 +183,8 @@ pub(crate) fn get_supported_protocols_cstr() -> &'static CStr {
              LinkAuth=1,3 \
              Microdesc=1-2 \
              Relay=1-2 \
-             Padding=1"
+             Padding=2 \
+             FlowCtrl=1"
         )
     }
 }
diff --git a/src/rust/tor_log/tor_log.rs b/src/rust/tor_log/tor_log.rs
index 98fccba5a..bbaf97129 100644
--- a/src/rust/tor_log/tor_log.rs
+++ b/src/rust/tor_log/tor_log.rs
@@ -99,14 +99,14 @@ pub mod log {
     /// Domain log types. These mirror definitions in src/lib/log/log.h
     /// C_RUST_COUPLED: src/lib/log/log.c, log severity types
     extern "C" {
-        static LD_NET_: u32;
-        static LD_GENERAL_: u32;
+        static LD_NET_: u64;
+        static LD_GENERAL_: u64;
     }
 
     /// Translate Rust defintions of log domain levels to C. This exposes a 1:1
     /// mapping between types.
     #[inline]
-    pub unsafe fn translate_domain(domain: LogDomain) -> u32 {
+    pub unsafe fn translate_domain(domain: LogDomain) -> u64 {
         match domain {
             LogDomain::Net => LD_NET_,
             LogDomain::General => LD_GENERAL_,
@@ -128,7 +128,7 @@ pub mod log {
     extern "C" {
         pub fn tor_log_string(
             severity: c_int,
-            domain: u32,
+            domain: u64,
             function: *const c_char,
             string: *const c_char,
         );
diff --git a/src/test/bench.c b/src/test/bench.c
index 65fa617cb..cf732df59 100644
--- a/src/test/bench.c
+++ b/src/test/bench.c
@@ -22,7 +22,7 @@
 #include <openssl/ec.h>
 #include <openssl/ecdh.h>
 #include <openssl/obj_mac.h>
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 #include "core/or/circuitlist.h"
 #include "app/config/config.h"
@@ -701,7 +701,7 @@ bench_ecdh_p224(void)
 {
   bench_ecdh_impl(NID_secp224r1, "P-224");
 }
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 static void
 bench_md_parse(void)
diff --git a/src/test/fuzz/fixup_filenames.sh b/src/test/fuzz/fixup_filenames.sh
index 68efc1abc..f730d532a 100755
--- a/src/test/fuzz/fixup_filenames.sh
+++ b/src/test/fuzz/fixup_filenames.sh
@@ -8,9 +8,9 @@ if [ ! -d "$1" ] ; then
 fi
 
 for fn in "$1"/* ; do
-    prev=`basename "$fn"`
-    post=`sha256sum "$fn" | sed -e 's/ .*//;'`
-    if [ "$prev" == "$post" ] ; then
+    prev=$(basename "$fn")
+    post=$(sha256sum "$fn" | sed -e 's/ .*//;')
+    if [ "$prev" = "$post" ] ; then
       echo "OK $prev"
     else
       echo "mv $prev $post"
diff --git a/src/test/fuzz/fuzz_multi.sh b/src/test/fuzz/fuzz_multi.sh
index b4a17ed8c..406ab498d 100755
--- a/src/test/fuzz/fuzz_multi.sh
+++ b/src/test/fuzz/fuzz_multi.sh
@@ -1,3 +1,5 @@
+#!/bin/sh
+
 MEMLIMIT_BYTES=21990500990976
 
 N_CPUS=1
@@ -6,9 +8,9 @@ if [ $# -ge 1 ]; then
     shift
 fi
 
-FILTER=echo
+FILTER="echo"
 
-for i in `seq -w "$N_CPUS"`; do
+for i in $(seq -w "$N_CPUS"); do
     if [ "$i" -eq 1 ]; then
         if [ "$N_CPUS" -eq 1 ]; then
             INSTANCE=""
diff --git a/src/test/fuzz/fuzz_strops.c b/src/test/fuzz/fuzz_strops.c
index 64a645305..459b4e21a 100644
--- a/src/test/fuzz/fuzz_strops.c
+++ b/src/test/fuzz/fuzz_strops.c
@@ -86,15 +86,13 @@ b16_enc(const chunk_t *inp)
   return ch;
 }
 
-#if 0
 static chunk_t *
 b32_dec(const chunk_t *inp)
 {
   chunk_t *ch = chunk_new(inp->len);//XXXX
   int r = base32_decode((char *)ch->buf, ch->len, (char *)inp->buf, inp->len);
   if (r >= 0) {
-    ch->len = r; // XXXX we need some way to get the actual length of
-                 // XXXX the output here.
+    ch->len = r;
   } else {
     chunk_free(ch);
   }
@@ -108,7 +106,6 @@ b32_enc(const chunk_t *inp)
   ch->len = strlen((char *) ch->buf);
   return ch;
 }
-#endif
 
 static chunk_t *
 b64_dec(const chunk_t *inp)
@@ -222,10 +219,7 @@ fuzz_main(const uint8_t *stdin_buf, size_t data_size)
       ENCODE_ROUNDTRIP(b16_enc, b16_dec, chunk_free_);
       break;
     case 1:
-      /*
-        XXXX see notes above about our base-32 functions.
       ENCODE_ROUNDTRIP(b32_enc, b32_dec, chunk_free_);
-      */
       break;
     case 2:
       ENCODE_ROUNDTRIP(b64_enc, b64_dec, chunk_free_);
@@ -241,6 +235,18 @@ fuzz_main(const uint8_t *stdin_buf, size_t data_size)
       kv_flags = 0;
       ENCODE_ROUNDTRIP(kv_enc, kv_dec, config_free_lines_);
       break;
+    case 7:
+      kv_flags = KV_OMIT_VALS;
+      ENCODE_ROUNDTRIP(kv_enc, kv_dec, config_free_lines_);
+      break;
+    case 8:
+      kv_flags = KV_QUOTED;
+      ENCODE_ROUNDTRIP(kv_enc, kv_dec, config_free_lines_);
+      break;
+    case 9:
+      kv_flags = KV_QUOTED|KV_OMIT_VALS;
+      ENCODE_ROUNDTRIP(kv_enc, kv_dec, config_free_lines_);
+      break;
     }
 
   return 0;
diff --git a/src/test/fuzz/fuzzing.h b/src/test/fuzz/fuzzing.h
index 150ac4aa7..2d278825e 100644
--- a/src/test/fuzz/fuzzing.h
+++ b/src/test/fuzz/fuzzing.h
@@ -9,5 +9,5 @@ int fuzz_main(const uint8_t *data, size_t sz);
 
 void disable_signature_checking(void);
 
-#endif /* FUZZING_H */
+#endif /* !defined(FUZZING_H) */
 
diff --git a/src/test/fuzz/fuzzing_common.c b/src/test/fuzz/fuzzing_common.c
index 387c865a9..6d0f9d7d6 100644
--- a/src/test/fuzz/fuzzing_common.c
+++ b/src/test/fuzz/fuzzing_common.c
@@ -137,7 +137,7 @@ LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
   return fuzz_main(Data, Size);
 }
 
-#else /* Not LLVM_FUZZ, so AFL. */
+#else /* !(defined(LLVM_FUZZ)) */
 
 int
 main(int argc, char **argv)
@@ -194,4 +194,4 @@ main(int argc, char **argv)
   return 0;
 }
 
-#endif
+#endif /* defined(LLVM_FUZZ) */
diff --git a/src/test/fuzz/minimize.sh b/src/test/fuzz/minimize.sh
index 87d3dda13..ce43812bb 100755
--- a/src/test/fuzz/minimize.sh
+++ b/src/test/fuzz/minimize.sh
@@ -7,7 +7,7 @@ if [ ! -d "$1" ] ; then
     exit 1
 fi
 
-which=`basename "$1"`
+which=$(basename "$1")
 
 mkdir "$1.out"
 afl-cmin -i "$1" -o "$1.out" -m none "./src/test/fuzz/fuzz-${which}"
diff --git a/src/test/fuzz_static_testcases.sh b/src/test/fuzz_static_testcases.sh
index f7b3adffb..b88335240 100755
--- a/src/test/fuzz_static_testcases.sh
+++ b/src/test/fuzz_static_testcases.sh
@@ -14,7 +14,7 @@ fi
 
 
 for fuzzer in "${builddir:-.}"/src/test/fuzz/fuzz-* ; do
-    f=`basename $fuzzer`
+    f=$(basename "$fuzzer")
     case="${f#fuzz-}"
     if [ -d "${TOR_FUZZ_CORPORA}/${case}" ]; then
         echo "Running tests for ${case}"
diff --git a/src/test/hs_test_helpers.c b/src/test/hs_test_helpers.c
index f2ae8398d..0a21fe576 100644
--- a/src/test/hs_test_helpers.c
+++ b/src/test/hs_test_helpers.c
@@ -21,26 +21,35 @@ hs_helper_build_intro_point(const ed25519_keypair_t *signing_kp, time_t now,
   /* For a usable intro point we need at least two link specifiers: One legacy
    * keyid and one ipv4 */
   {
-    hs_desc_link_specifier_t *ls_legacy = tor_malloc_zero(sizeof(*ls_legacy));
-    hs_desc_link_specifier_t *ls_v4 = tor_malloc_zero(sizeof(*ls_v4));
-    ls_legacy->type = LS_LEGACY_ID;
-    memcpy(ls_legacy->u.legacy_id, "0299F268FCA9D55CD157976D39AE92B4B455B3A8",
-           DIGEST_LEN);
-    ls_v4->u.ap.port = 9001;
-    int family = tor_addr_parse(&ls_v4->u.ap.addr, addr);
+    tor_addr_t a;
+    tor_addr_make_unspec(&a);
+    link_specifier_t *ls_legacy = link_specifier_new();
+    link_specifier_t *ls_ip = link_specifier_new();
+    link_specifier_set_ls_type(ls_legacy, LS_LEGACY_ID);
+    memset(link_specifier_getarray_un_legacy_id(ls_legacy), 'C',
+           link_specifier_getlen_un_legacy_id(ls_legacy));
+    int family = tor_addr_parse(&a, addr);
     switch (family) {
     case AF_INET:
-          ls_v4->type = LS_IPV4;
+          link_specifier_set_ls_type(ls_ip, LS_IPV4);
+          link_specifier_set_un_ipv4_addr(ls_ip, tor_addr_to_ipv4h(&a));
+          link_specifier_set_un_ipv4_port(ls_ip, 9001);
           break;
         case AF_INET6:
-          ls_v4->type = LS_IPV6;
+          link_specifier_set_ls_type(ls_ip, LS_IPV6);
+          memcpy(link_specifier_getarray_un_ipv6_addr(ls_ip),
+                 tor_addr_to_in6_addr8(&a),
+                 link_specifier_getlen_un_ipv6_addr(ls_ip));
+          link_specifier_set_un_ipv6_port(ls_ip, 9001);
           break;
         default:
-          /* Stop the test, not suppose to have an error. */
-          tt_int_op(family, OP_EQ, AF_INET);
+          /* Stop the test, not supposed to have an error.
+           * Compare with -1 to show the actual family.
+           */
+          tt_int_op(family, OP_EQ, -1);
     }
     smartlist_add(ip->link_specifiers, ls_legacy);
-    smartlist_add(ip->link_specifiers, ls_v4);
+    smartlist_add(ip->link_specifiers, ls_ip);
   }
 
   ret = ed25519_keypair_generate(&auth_kp, 0);
@@ -202,7 +211,6 @@ void
 hs_helper_desc_equal(const hs_descriptor_t *desc1,
                      const hs_descriptor_t *desc2)
 {
-  char *addr1 = NULL, *addr2 = NULL;
   /* Plaintext data section. */
   tt_int_op(desc1->plaintext_data.version, OP_EQ,
             desc2->plaintext_data.version);
@@ -291,35 +299,57 @@ hs_helper_desc_equal(const hs_descriptor_t *desc1,
       tt_int_op(smartlist_len(ip1->link_specifiers), ==,
                 smartlist_len(ip2->link_specifiers));
       for (int j = 0; j < smartlist_len(ip1->link_specifiers); j++) {
-        hs_desc_link_specifier_t *ls1 = smartlist_get(ip1->link_specifiers, j),
-                                 *ls2 = smartlist_get(ip2->link_specifiers, j);
-        tt_int_op(ls1->type, ==, ls2->type);
-        switch (ls1->type) {
+        link_specifier_t *ls1 = smartlist_get(ip1->link_specifiers, j),
+                         *ls2 = smartlist_get(ip2->link_specifiers, j);
+        tt_int_op(link_specifier_get_ls_type(ls1), ==,
+                  link_specifier_get_ls_type(ls2));
+        switch (link_specifier_get_ls_type(ls1)) {
           case LS_IPV4:
+            {
+              uint32_t addr1 = link_specifier_get_un_ipv4_addr(ls1);
+              uint32_t addr2 = link_specifier_get_un_ipv4_addr(ls2);
+              tt_int_op(addr1, OP_EQ, addr2);
+              uint16_t port1 = link_specifier_get_un_ipv4_port(ls1);
+              uint16_t port2 = link_specifier_get_un_ipv4_port(ls2);
+              tt_int_op(port1, ==, port2);
+            }
+            break;
           case LS_IPV6:
             {
-              addr1 = tor_addr_to_str_dup(&ls1->u.ap.addr);
-              addr2 = tor_addr_to_str_dup(&ls2->u.ap.addr);
-              tt_str_op(addr1, OP_EQ, addr2);
-              tor_free(addr1);
-              tor_free(addr2);
-              tt_int_op(ls1->u.ap.port, ==, ls2->u.ap.port);
+              const uint8_t *addr1 =
+                link_specifier_getconstarray_un_ipv6_addr(ls1);
+              const uint8_t *addr2 =
+                link_specifier_getconstarray_un_ipv6_addr(ls2);
+              tt_int_op(link_specifier_getlen_un_ipv6_addr(ls1), OP_EQ,
+                        link_specifier_getlen_un_ipv6_addr(ls2));
+              tt_mem_op(addr1, OP_EQ, addr2,
+                        link_specifier_getlen_un_ipv6_addr(ls1));
+              uint16_t port1 = link_specifier_get_un_ipv6_port(ls1);
+              uint16_t port2 = link_specifier_get_un_ipv6_port(ls2);
+              tt_int_op(port1, ==, port2);
             }
             break;
           case LS_LEGACY_ID:
-            tt_mem_op(ls1->u.legacy_id, OP_EQ, ls2->u.legacy_id,
-                      sizeof(ls1->u.legacy_id));
+            {
+              const uint8_t *id1 =
+                link_specifier_getconstarray_un_legacy_id(ls1);
+              const uint8_t *id2 =
+                link_specifier_getconstarray_un_legacy_id(ls2);
+              tt_int_op(link_specifier_getlen_un_legacy_id(ls1), OP_EQ,
+                        link_specifier_getlen_un_legacy_id(ls2));
+              tt_mem_op(id1, OP_EQ, id2,
+                        link_specifier_getlen_un_legacy_id(ls1));
+            }
             break;
           default:
             /* Unknown type, caught it and print its value. */
-            tt_int_op(ls1->type, OP_EQ, -1);
+            tt_int_op(link_specifier_get_ls_type(ls1), OP_EQ, -1);
         }
       }
     }
   }
 
  done:
-  tor_free(addr1);
-  tor_free(addr2);
+  ;
 }
 
diff --git a/src/test/include.am b/src/test/include.am
index d585c2a38..85f9c9f88 100644
--- a/src/test/include.am
+++ b/src/test/include.am
@@ -32,8 +32,15 @@ endif
 
 if USEPYTHON
 TESTSCRIPTS += src/test/test_ntor.sh src/test/test_hs_ntor.sh src/test/test_bt.sh
+
+if COVERAGE_ENABLED
+# ...
+else
+# Only do this when coverage is not on, since it invokes lots of code
+# in a kind of unpredictable way.
 TESTSCRIPTS += src/test/test_rebind.sh
 endif
+endif
 
 TESTS += src/test/test src/test/test-slow src/test/test-memwipe \
 	src/test/test_workqueue \
@@ -46,10 +53,8 @@ TESTS += src/test/test src/test/test-slow src/test/test-memwipe \
 TEST_CHUTNEY_FLAVORS = basic-min bridges-min hs-v2-min hs-v3-min \
 	single-onion-v23
 # only run if we can ping6 ::1 (localhost)
-# IPv6-only v3 single onion services don't work yet, so we don't test the
-# single-onion-v23-ipv6-md flavor
 TEST_CHUTNEY_FLAVORS_IPV6 = bridges+ipv6-min ipv6-exit-min hs-v23-ipv6-md \
-	single-onion-ipv6-md
+	single-onion-v23-ipv6-md
 # only run if we can find a stable (or simply another) version of tor
 TEST_CHUTNEY_FLAVORS_MIXED = mixed+hs-v2
 
@@ -85,10 +90,13 @@ src_test_AM_CPPFLAGS = -DSHARE_DATADIR="\"$(datadir)\"" \
 src_test_test_SOURCES =
 
 if UNITTESTS_ENABLED
+
+# ADD_C_FILE: INSERT SOURCES HERE.
 src_test_test_SOURCES += \
 	src/test/log_test_helpers.c \
 	src/test/hs_test_helpers.c \
 	src/test/rend_test_helpers.c \
+	src/test/rng_test_helpers.c \
 	src/test/test.c \
 	src/test/test_accounting.c \
 	src/test/test_addr.c \
@@ -126,6 +134,7 @@ src_test_test_SOURCES += \
 	src/test/test_dir.c \
 	src/test/test_dir_common.c \
 	src/test/test_dir_handle_get.c \
+	src/test/test_dispatch.c \
 	src/test/test_dos.c \
 	src/test/test_entryconn.c \
 	src/test/test_entrynodes.c \
@@ -150,6 +159,7 @@ src_test_test_SOURCES += \
 	src/test/test_logging.c \
 	src/test/test_mainloop.c \
 	src/test/test_microdesc.c \
+	src/test/test_namemap.c \
 	src/test/test_netinfo.c \
 	src/test/test_nodelist.c \
 	src/test/test_oom.c \
@@ -165,6 +175,8 @@ src_test_test_SOURCES += \
 	src/test/test_proto_misc.c \
 	src/test/test_protover.c \
 	src/test/test_pt.c \
+	src/test/test_pubsub_build.c \
+	src/test/test_pubsub_msg.c \
 	src/test/test_relay.c \
 	src/test/test_relaycell.c \
 	src/test/test_relaycrypt.c \
@@ -175,6 +187,7 @@ src_test_test_SOURCES += \
 	src/test/test_routerlist.c \
 	src/test/test_routerset.c \
 	src/test/test_scheduler.c \
+	src/test/test_sendme.c \
 	src/test/test_shared_random.c \
 	src/test/test_socks.c \
 	src/test/test_status.c \
@@ -207,10 +220,13 @@ endif
 src_test_test_slow_SOURCES =
 if UNITTESTS_ENABLED
 src_test_test_slow_SOURCES += \
+	src/test/rng_test_helpers.c \
 	src/test/test_slow.c \
 	src/test/test_crypto_slow.c \
 	src/test/test_process_slow.c \
 	src/test/test_prob_distr.c \
+	src/test/ptr_helpers.c \
+	src/test/test_ptr_slow.c \
 	src/test/testing_common.c \
 	src/test/testing_rsakeys.c \
 	src/ext/tinytest.c
@@ -308,12 +324,15 @@ src_test_test_timers_LDADD = \
 	@TOR_LZMA_LIBS@
 src_test_test_timers_LDFLAGS = $(src_test_test_LDFLAGS)
 
+# ADD_C_FILE: INSERT HEADERS HERE.
 noinst_HEADERS+= \
 	src/test/fakechans.h \
 	src/test/hs_test_helpers.h \
 	src/test/log_test_helpers.h \
 	src/test/rend_test_helpers.h \
+	src/test/rng_test_helpers.h \
 	src/test/test.h \
+	src/test/ptr_helpers.h \
 	src/test/test_helpers.h \
 	src/test/test_dir_common.h \
 	src/test/test_connection.h \
diff --git a/src/test/ope_ref.py b/src/test/ope_ref.py
index f9bd97c54..b2f701256 100644
--- a/src/test/ope_ref.py
+++ b/src/test/ope_ref.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3
 # Copyright 2018-2019, The Tor Project, Inc. See LICENSE for licensing info.
 
 # Reference implementation for our rudimentary OPE code, used to
diff --git a/src/test/ptr_helpers.c b/src/test/ptr_helpers.c
new file mode 100644
index 000000000..a55ab437f
--- /dev/null
+++ b/src/test/ptr_helpers.c
@@ -0,0 +1,50 @@
+/* Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "test/ptr_helpers.h"
+
+/**
+ * Cast <b> (inptr_t value) to a void pointer.
+ */
+void *
+cast_intptr_to_voidstar(intptr_t x)
+{
+  void *r = (void *)x;
+
+  return r;
+}
+
+/**
+ * Cast x (void pointer) to inptr_t value.
+ */
+intptr_t
+cast_voidstar_to_intptr(void *x)
+{
+  intptr_t r = (intptr_t)x;
+
+  return r;
+}
+
+/**
+ * Cast x (uinptr_t value) to void pointer.
+ */
+void *
+cast_uintptr_to_voidstar(uintptr_t x)
+{
+  void *r = (void *)x;
+
+  return r;
+}
+
+/**
+ * Cast x (void pointer) to uinptr_t value.
+ */
+uintptr_t
+cast_voidstar_to_uintptr(void *x)
+{
+  uintptr_t r = (uintptr_t)x;
+
+  return r;
+}
diff --git a/src/test/ptr_helpers.h b/src/test/ptr_helpers.h
new file mode 100644
index 000000000..7349bddd5
--- /dev/null
+++ b/src/test/ptr_helpers.h
@@ -0,0 +1,23 @@
+/* Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_PTR_HELPERS_H
+#define TOR_PTR_HELPERS_H
+
+#include <stdint.h>
+
+void *
+cast_intptr_to_voidstar(intptr_t x);
+
+intptr_t
+cast_voidstar_to_intptr(void *x);
+
+void *
+cast_uintptr_to_voidstar(uintptr_t x);
+
+uintptr_t
+cast_voidstar_to_uintptr(void *x);
+
+#endif /* !defined(TOR_PTR_HELPERS_H) */
diff --git a/src/test/rng_test_helpers.c b/src/test/rng_test_helpers.c
new file mode 100644
index 000000000..7024fb579
--- /dev/null
+++ b/src/test/rng_test_helpers.c
@@ -0,0 +1,259 @@
+/* Copyright (c) 2018-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file rng_test_helpers.c
+ * \brief Helpers for overriding PRNGs during unit tests.
+ *
+ * We define two PRNG overrides: a "reproducible PRNG" where the seed is
+ * chosen randomly but the stream can be replayed later on in case a bug is
+ * found, and a "deterministic PRNG" where the seed is fixed in the unit
+ * tests.
+ *
+ * Obviously, this code is testing-only.
+ */
+
+#include "orconfig.h"
+#include "core/or/or.h"
+
+#include "lib/crypt_ops/crypto_rand.h"
+#include "ext/tinytest.h"
+
+#include "test/rng_test_helpers.h"
+
+#ifndef TOR_UNIT_TESTS
+#error "No. Never link this code into Tor proper."
+#endif
+
+/**
+ * True iff the RNG is currently replaced.  Prevents double-replacement.
+ **/
+static bool rng_is_replaced = false;
+
+/**
+ * Mutex to protect deterministic prng.
+ *
+ * Note that if you actually _use_ the prng from two threads at the same time,
+ * the results will probably be nondeterministic anyway.
+ */
+static tor_mutex_t *rng_mutex = NULL;
+
+/**
+ * Cached old value for the thread prng.
+ **/
+static crypto_fast_rng_t *stored_fast_rng = NULL;
+
+/** replacement for crypto_strongest_rand that delegates to crypto_rand. */
+static void
+mock_crypto_strongest_rand(uint8_t *out, size_t len)
+{
+  crypto_rand((char *)out, len);
+}
+
+/* This is the seed of the deterministic randomness. */
+static uint8_t rng_seed[16];
+static crypto_xof_t *rng_xof = NULL;
+
+/**
+ * Print the seed for our PRNG to stdout.  We use this when we're failed
+ * test that had a reproducible RNG set.
+ **/
+void
+testing_dump_reproducible_rng_seed(void)
+{
+  printf("\n"
+         "Seed: %s\n",
+         hex_str((const char*)rng_seed, sizeof(rng_seed)));
+}
+
+/** Produce deterministic randomness for the stochastic tests using the global
+ * rng_xof output.
+ *
+ * This function produces deterministic data over multiple calls iff it's
+ * called in the same call order with the same 'n' parameter.
+ * If not, outputs will deviate. */
+static void
+crypto_rand_deterministic(char *out, size_t n)
+{
+  tor_assert(rng_xof);
+  tor_mutex_acquire(rng_mutex);
+  crypto_xof_squeeze_bytes(rng_xof, (uint8_t*)out, n);
+  tor_mutex_release(rng_mutex);
+}
+
+/**
+ * Implementation helper: override our crypto_rand() PRNG with a given seed of
+ * length <b>seed_len</b>.  Overlong seeds are truncated; short ones are
+ * padded.
+ **/
+static void
+enable_deterministic_rng_impl(const uint8_t *seed, size_t seed_len)
+{
+  tor_assert(!rng_is_replaced);
+  tor_assert(crypto_rand == crypto_rand__real);
+
+  memset(rng_seed, 0, sizeof(rng_seed));
+  memcpy(rng_seed, seed, MIN(seed_len, sizeof(rng_seed)));
+
+  rng_mutex = tor_mutex_new();
+
+  crypto_xof_free(rng_xof);
+  rng_xof = crypto_xof_new();
+  crypto_xof_add_bytes(rng_xof, rng_seed, sizeof(rng_seed));
+  MOCK(crypto_rand, crypto_rand_deterministic);
+  MOCK(crypto_strongest_rand_, mock_crypto_strongest_rand);
+
+  uint8_t fast_rng_seed[CRYPTO_FAST_RNG_SEED_LEN];
+  memset(fast_rng_seed, 0xff, sizeof(fast_rng_seed));
+  memcpy(fast_rng_seed, rng_seed, MIN(sizeof(rng_seed),
+                                      sizeof(fast_rng_seed)));
+  crypto_fast_rng_t *fast_rng = crypto_fast_rng_new_from_seed(fast_rng_seed);
+  crypto_fast_rng_disable_reseed(fast_rng);
+  stored_fast_rng = crypto_replace_thread_fast_rng(fast_rng);
+
+  rng_is_replaced = true;
+}
+
+/**
+ * Replace our get_thread_fast_rng(), crypto_rand() and
+ * crypto_strongest_rand() prngs with a variant that generates all of its
+ * output deterministically from a randomly chosen seed.  In the event of an
+ * error, you can log the seed later on with
+ * testing_dump_reproducible_rng_seed.
+ **/
+void
+testing_enable_reproducible_rng(void)
+{
+  const char *provided_seed = getenv("TOR_TEST_RNG_SEED");
+  if (provided_seed) {
+    size_t hexlen = strlen(provided_seed);
+    size_t seedlen = hexlen / 2;
+    uint8_t *seed = tor_malloc(hexlen / 2);
+    if (base16_decode((char*)seed, seedlen, provided_seed, hexlen) < 0) {
+      puts("Cannot decode value in TOR_TEST_RNG_SEED");
+      exit(1);
+    }
+    enable_deterministic_rng_impl(seed, seedlen);
+    tor_free(seed);
+  } else {
+    uint8_t seed[16];
+    crypto_rand((char*)seed, sizeof(seed));
+    enable_deterministic_rng_impl(seed, sizeof(seed));
+  }
+}
+
+/**
+ * Replace our get_thread_fast_rng(), crypto_rand() and
+ * crypto_strongest_rand() prngs with a variant that generates all of its
+ * output deterministically from a fixed seed.  This variant is mainly useful
+ * for cases when we don't want coverage to change between runs.
+ *
+ * USAGE NOTE: Test correctness SHOULD NOT depend on the specific output of
+ * this "rng".  If you need a specific output, use
+ * testing_enable_prefilled_rng() instead.
+ **/
+void
+testing_enable_deterministic_rng(void)
+{
+  static const uint8_t quotation[] =
+    "What will it be? A tree? A weed? "
+    "Each one is started from a seed."; // -- Mary Ann Hoberman
+  enable_deterministic_rng_impl(quotation, sizeof(quotation));
+}
+
+static uint8_t *prefilled_rng_buffer = NULL;
+static size_t prefilled_rng_buflen;
+static size_t prefilled_rng_idx;
+
+/**
+ * crypto_rand() replacement that returns canned data.
+ **/
+static void
+crypto_rand_prefilled(char *out, size_t n)
+{
+  tor_mutex_acquire(rng_mutex);
+  while (n) {
+    size_t n_to_copy = MIN(prefilled_rng_buflen - prefilled_rng_idx, n);
+    memcpy(out, prefilled_rng_buffer + prefilled_rng_idx, n_to_copy);
+    out += n_to_copy;
+    n -= n_to_copy;
+    prefilled_rng_idx += n_to_copy;
+
+    if (prefilled_rng_idx == prefilled_rng_buflen) {
+      prefilled_rng_idx = 0;
+    }
+  }
+  tor_mutex_release(rng_mutex);
+}
+
+/**
+ * Replace our crypto_rand() and crypto_strongest_rand() prngs with a variant
+ * that yields output from a buffer.  If it reaches the end of the buffer, it
+ * starts over.
+ *
+ * Note: the get_thread_fast_rng() prng is not replaced by this; we'll need
+ * more code to support that.
+ **/
+void
+testing_enable_prefilled_rng(const void *buffer, size_t buflen)
+{
+  tor_assert(buflen > 0);
+  tor_assert(!rng_mutex);
+  rng_mutex = tor_mutex_new();
+
+  tor_mutex_acquire(rng_mutex);
+
+  prefilled_rng_buffer = tor_memdup(buffer, buflen);
+  prefilled_rng_buflen = buflen;
+  prefilled_rng_idx = 0;
+
+  tor_mutex_release(rng_mutex);
+
+  MOCK(crypto_rand, crypto_rand_prefilled);
+  MOCK(crypto_strongest_rand_, mock_crypto_strongest_rand);
+}
+
+/**
+ * Reset the position in the prefilled RNG buffer to the start.
+ */
+void
+testing_prefilled_rng_reset(void)
+{
+  tor_mutex_acquire(rng_mutex);
+  prefilled_rng_idx = 0;
+  tor_mutex_release(rng_mutex);
+}
+
+/**
+ * Undo the overrides for our PRNG.  To be used at the end of testing.
+ *
+ * Note that this function should be safe to call even if the rng has not
+ * yet been replaced.
+ **/
+void
+testing_disable_rng_override(void)
+{
+  crypto_xof_free(rng_xof);
+  tor_free(prefilled_rng_buffer);
+  UNMOCK(crypto_rand);
+  UNMOCK(crypto_strongest_rand_);
+  tor_mutex_free(rng_mutex);
+
+  crypto_fast_rng_t *rng = crypto_replace_thread_fast_rng(stored_fast_rng);
+  crypto_fast_rng_free(rng);
+
+  rng_is_replaced = false;
+}
+
+/**
+ * As testing_disable_rng_override(), but dump the seed if the current
+ * test has failed.
+ */
+void
+testing_disable_reproducible_rng(void)
+{
+  if (tinytest_cur_test_has_failed()) {
+    testing_dump_reproducible_rng_seed();
+  }
+  testing_disable_rng_override();
+}
diff --git a/src/test/rng_test_helpers.h b/src/test/rng_test_helpers.h
new file mode 100644
index 000000000..d7925148a
--- /dev/null
+++ b/src/test/rng_test_helpers.h
@@ -0,0 +1,25 @@
+/* Copyright (c) 2017-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_RNG_TEST_HELPERS_H
+#define TOR_RNG_TEST_HELPERS_H
+
+#include "core/or/or.h"
+
+void testing_enable_deterministic_rng(void);
+void testing_enable_reproducible_rng(void);
+void testing_enable_prefilled_rng(const void *buffer, size_t buflen);
+
+void testing_prefilled_rng_reset(void);
+
+void testing_disable_rng_override(void);
+
+void testing_disable_reproducible_rng(void);
+#define testing_disable_deterministic_rng() \
+  testing_disable_rng_override()
+#define testing_disable_prefilled_rng() \
+  testing_disable_rng_override()
+
+void testing_dump_reproducible_rng_seed(void);
+
+#endif /* !defined(TOR_RNG_TEST_HELPERS_H) */
diff --git a/src/test/test-memwipe.c b/src/test/test-memwipe.c
index 43754ed1c..3f952e484 100644
--- a/src/test/test-memwipe.c
+++ b/src/test/test-memwipe.c
@@ -49,7 +49,7 @@ const char *s = NULL;
  * us do bad things, such as access freed buffers, without crashing. */
 extern const char *malloc_options;
 const char *malloc_options = "sufjj";
-#endif
+#endif /* defined(OpenBSD) */
 
 static unsigned
 fill_a_buffer_memset(void)
diff --git a/src/test/test-network.sh b/src/test/test-network.sh
index b7a9f1b3c..5ef995f1a 100755
--- a/src/test/test-network.sh
+++ b/src/test/test-network.sh
@@ -5,7 +5,7 @@
 # If we already know CHUTNEY_PATH, don't bother with argument parsing
 TEST_NETWORK="$CHUTNEY_PATH/tools/test-network.sh"
 # Call the chutney version of this script, if it exists, and we can find it
-if [ -d "$CHUTNEY_PATH" -a -x "$TEST_NETWORK" ]; then
+if [ -d "$CHUTNEY_PATH" ] && [ -x "$TEST_NETWORK" ]; then
     # we can't produce any output, because we might be --quiet
     # this preserves arguments with spaces correctly
     exec "$TEST_NETWORK" "$@"
@@ -16,34 +16,16 @@ fi
 # Do we output anything at all?
 ECHO="${ECHO:-echo}"
 # Output is prefixed with the name of the script
-myname=$(basename $0)
-
-# Save the arguments before we destroy them
-# This might not preserve arguments with spaces in them
-ORIGINAL_ARGS="$@"
+myname=$(basename "$0")
 
 # We need to find CHUTNEY_PATH, so that we can call the version of this script
 # in chutney/tools with the same arguments. We also need to respect --quiet.
-until [ -z "$1" ]
-do
-  case "$1" in
-    --chutney-path)
-      CHUTNEY_PATH="$2"
-      shift
-    ;;
-    --tor-path)
-      TOR_DIR="$2"
-      shift
-    ;;
-    --quiet)
-      ECHO=true
-    ;;
-    *)
-      # maybe chutney's test-network.sh can handle it
-    ;;
-  esac
-  shift
-done
+CHUTNEY_PATH=$(echo "$@" | awk -F '--chutney-path ' '{sub(" .*","",$2); print $2}')
+TOR_DIR=$(echo "$@" | awk -F '--tor-dir ' '{sub(" .*","",$2); print $2}')
+
+if echo "$@" | grep -e "--quiet" > /dev/null; then
+  ECHO=true
+fi
 
 # optional: $TOR_DIR is the tor build directory
 # it's used to find the location of tor binaries
@@ -52,12 +34,12 @@ done
 #  - if $PWD looks like a tor build directory, set it to $PWD, or
 #  - unset $TOR_DIR, and let chutney fall back to finding tor binaries in $PATH
 if [ ! -d "$TOR_DIR" ]; then
-    if [ -d "$BUILDDIR/src/core/or" -a -d "$BUILDDIR/src/tools" ]; then
+    if [ -d "$BUILDDIR/src/core/or" ] && [ -d "$BUILDDIR/src/tools" ]; then
         # Choose the build directory
         # But only if it looks like one
         $ECHO "$myname: \$TOR_DIR not set, trying \$BUILDDIR"
         TOR_DIR="$BUILDDIR"
-    elif [ -d "$PWD/src/core/or" -a -d "$PWD/src/tools" ]; then
+    elif [ -d "$PWD/src/core/or" ] && [ -d "$PWD/src/tools" ]; then
         # Guess the tor directory is the current directory
         # But only if it looks like one
         $ECHO "$myname: \$TOR_DIR not set, trying \$PWD"
@@ -73,12 +55,12 @@ fi
 #  - if $PWD looks like a chutney directory, set it to $PWD, or
 #  - set it based on $TOR_DIR, expecting chutney to be next to tor, or
 #  - fail and tell the user how to clone the chutney repository
-if [ ! -d "$CHUTNEY_PATH" -o ! -x "$CHUTNEY_PATH/chutney" ]; then
+if [ ! -d "$CHUTNEY_PATH" ] || [ ! -x "$CHUTNEY_PATH/chutney" ]; then
     if [ -x "$PWD/chutney" ]; then
         $ECHO "$myname: \$CHUTNEY_PATH not valid, trying \$PWD"
         CHUTNEY_PATH="$PWD"
-    elif [ -d "$TOR_DIR" -a -d "$TOR_DIR/../chutney" -a \
-           -x "$TOR_DIR/../chutney/chutney" ]; then
+    elif [ -d "$TOR_DIR" ] && [ -d "$TOR_DIR/../chutney" ] && \
+          [ -x "$TOR_DIR/../chutney/chutney" ]; then
         $ECHO "$myname: \$CHUTNEY_PATH not valid, trying \$TOR_DIR/../chutney"
         CHUTNEY_PATH="$TOR_DIR/../chutney"
     else
@@ -94,12 +76,12 @@ fi
 
 TEST_NETWORK="$CHUTNEY_PATH/tools/test-network.sh"
 # Call the chutney version of this script, if it exists, and we can find it
-if [ -d "$CHUTNEY_PATH" -a -x "$TEST_NETWORK" ]; then
+if [ -d "$CHUTNEY_PATH" ] && [ -x "$TEST_NETWORK" ]; then
     $ECHO "$myname: Calling newer chutney script $TEST_NETWORK"
     # this may fail if some arguments have spaces in them
     # if so, set CHUTNEY_PATH before calling test-network.sh, and spaces
     # will be handled correctly
-    exec "$TEST_NETWORK" $ORIGINAL_ARGS
+    exec "$TEST_NETWORK" "$@"
 else
     $ECHO "$myname: Could not find tools/test-network.sh in CHUTNEY_PATH."
     $ECHO "$myname: Please update your chutney using 'git pull'."
diff --git a/src/test/test.c b/src/test/test.c
index 25e9da559..cac98dd83 100644
--- a/src/test/test.c
+++ b/src/test/test.c
@@ -12,6 +12,7 @@
 #include "lib/crypt_ops/crypto_dh.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "app/config/or_state_st.h"
+#include "test/rng_test_helpers.h"
 
 #include <stdio.h>
 #ifdef HAVE_FCNTL_H
@@ -283,7 +284,7 @@ test_fast_handshake(void *arg)
   /* First, test an entire handshake. */
   memset(client_handshake, 0, sizeof(client_handshake));
   tt_int_op(0, OP_EQ, fast_onionskin_create(&state, client_handshake));
-  tt_assert(! tor_mem_is_zero((char*)client_handshake,
+  tt_assert(! fast_mem_is_zero((char*)client_handshake,
                               sizeof(client_handshake)));
 
   tt_int_op(0, OP_EQ,
@@ -354,18 +355,6 @@ test_onion_queues(void *arg)
   tor_free(onionskin);
 }
 
-static crypto_cipher_t *crypto_rand_aes_cipher = NULL;
-
-// Mock replacement for crypto_rand: Generates bytes from a provided AES_CTR
-// cipher in <b>crypto_rand_aes_cipher</b>.
-static void
-crypto_rand_deterministic_aes(char *out, size_t n)
-{
-  tor_assert(crypto_rand_aes_cipher);
-  memset(out, 0, n);
-  crypto_cipher_crypt_inplace(crypto_rand_aes_cipher, out, n);
-}
-
 static void
 test_circuit_timeout(void *arg)
 {
@@ -397,8 +386,7 @@ test_circuit_timeout(void *arg)
 
   // Use a deterministic RNG here, or else we'll get nondeterministic
   // coverage in some of the circuitstats functions.
-  MOCK(crypto_rand, crypto_rand_deterministic_aes);
-  crypto_rand_aes_cipher = crypto_cipher_new("xyzzyplughplover");
+  testing_enable_deterministic_rng();
 
   circuitbuild_running_unit_tests();
 #define timeout0 (build_time_t)(30*1000.0)
@@ -534,8 +522,8 @@ test_circuit_timeout(void *arg)
   circuit_build_times_free_timeouts(&final);
   or_state_free(state);
   teardown_periodic_events();
-  UNMOCK(crypto_rand);
-  crypto_cipher_free(crypto_rand_aes_cipher);
+
+  testing_disable_deterministic_rng();
 }
 
 /** Test encoding and parsing of rendezvous service descriptors. */
@@ -857,6 +845,7 @@ struct testgroup_t testgroups[] = {
   { "consdiff/", consdiff_tests },
   { "consdiffmgr/", consdiffmgr_tests },
   { "container/", container_tests },
+  { "container/namemap/", namemap_tests },
   { "control/", controller_tests },
   { "control/btrack/", btrack_tests },
   { "control/event/", controller_event_tests },
@@ -872,6 +861,7 @@ struct testgroup_t testgroups[] = {
   { "dir/voting/flags/", voting_flags_tests },
   { "dir/voting/schedule/", voting_schedule_tests },
   { "dir_handle_get/", dir_handle_get_tests },
+  { "dispatch/", dispatch_tests, },
   { "dns/", dns_tests },
   { "dos/", dos_tests },
   { "entryconn/", entryconn_tests },
@@ -909,6 +899,8 @@ struct testgroup_t testgroups[] = {
   { "proto/misc/", proto_misc_tests },
   { "protover/", protover_tests },
   { "pt/", pt_tests },
+  { "pubsub/build/", pubsub_build_tests },
+  { "pubsub/msg/", pubsub_msg_tests },
   { "relay/" , relay_tests },
   { "relaycell/", relaycell_tests },
   { "relaycrypt/", relaycrypt_tests },
@@ -919,6 +911,7 @@ struct testgroup_t testgroups[] = {
   { "routerlist/", routerlist_tests },
   { "routerset/" , routerset_tests },
   { "scheduler/", scheduler_tests },
+  { "sendme/", sendme_tests },
   { "shared-random/", sr_tests },
   { "socks/", socks_tests },
   { "status/" , status_tests },
diff --git a/src/test/test.h b/src/test/test.h
index 256443298..167fd090a 100644
--- a/src/test/test.h
+++ b/src/test/test.h
@@ -210,6 +210,7 @@ extern struct testcase_t crypto_rng_tests[];
 extern struct testcase_t crypto_tests[];
 extern struct testcase_t dir_handle_get_tests[];
 extern struct testcase_t dir_tests[];
+extern struct testcase_t dispatch_tests[];
 extern struct testcase_t dns_tests[];
 extern struct testcase_t dos_tests[];
 extern struct testcase_t entryconn_tests[];
@@ -235,6 +236,7 @@ extern struct testcase_t link_handshake_tests[];
 extern struct testcase_t logging_tests[];
 extern struct testcase_t mainloop_tests[];
 extern struct testcase_t microdesc_tests[];
+extern struct testcase_t namemap_tests[];
 extern struct testcase_t netinfo_tests[];
 extern struct testcase_t nodelist_tests[];
 extern struct testcase_t oom_tests[];
@@ -252,6 +254,8 @@ extern struct testcase_t proto_http_tests[];
 extern struct testcase_t proto_misc_tests[];
 extern struct testcase_t protover_tests[];
 extern struct testcase_t pt_tests[];
+extern struct testcase_t pubsub_build_tests[];
+extern struct testcase_t pubsub_msg_tests[];
 extern struct testcase_t relay_tests[];
 extern struct testcase_t relaycell_tests[];
 extern struct testcase_t relaycrypt_tests[];
@@ -262,6 +266,7 @@ extern struct testcase_t routerkeys_tests[];
 extern struct testcase_t routerlist_tests[];
 extern struct testcase_t routerset_tests[];
 extern struct testcase_t scheduler_tests[];
+extern struct testcase_t sendme_tests[];
 extern struct testcase_t socks_tests[];
 extern struct testcase_t sr_tests[];
 extern struct testcase_t status_tests[];
@@ -278,6 +283,7 @@ extern struct testcase_t x509_tests[];
 
 extern struct testcase_t slow_crypto_tests[];
 extern struct testcase_t slow_process_tests[];
+extern struct testcase_t slow_ptr_tests[];
 
 extern struct testgroup_t testgroups[];
 
diff --git a/src/test/test_addr.c b/src/test/test_addr.c
index fb8df5f0f..05d8bf6c7 100644
--- a/src/test/test_addr.c
+++ b/src/test/test_addr.c
@@ -11,6 +11,7 @@
 #include "feature/client/addressmap.h"
 #include "test/log_test_helpers.h"
 #include "lib/net/resolve.h"
+#include "test/rng_test_helpers.h"
 
 #ifdef HAVE_SYS_UN_H
 #include <sys/un.h>
@@ -239,7 +240,7 @@ test_addr_ip6_helpers(void *arg)
   tt_int_op(0,OP_EQ, tor_addr_lookup("9000::5", AF_UNSPEC, &t1));
   tt_int_op(AF_INET6,OP_EQ, tor_addr_family(&t1));
   tt_int_op(0x90,OP_EQ, tor_addr_to_in6_addr8(&t1)[0]);
-  tt_assert(tor_mem_is_zero((char*)tor_addr_to_in6_addr8(&t1)+1, 14));
+  tt_assert(fast_mem_is_zero((char*)tor_addr_to_in6_addr8(&t1)+1, 14));
   tt_int_op(0x05,OP_EQ, tor_addr_to_in6_addr8(&t1)[15]);
 
   /* === Test pton: valid af_inet6 */
@@ -696,7 +697,7 @@ test_addr_ip6_helpers(void *arg)
                               &t1,&mask,&port1,&port2);
   tt_int_op(r,OP_EQ,AF_INET6);
   tt_int_op(tor_addr_family(&t1),OP_EQ,AF_INET6);
-  tt_assert(tor_mem_is_zero((const char*)tor_addr_to_in6_addr32(&t1), 16));
+  tt_assert(fast_mem_is_zero((const char*)tor_addr_to_in6_addr32(&t1), 16));
   tt_int_op(mask,OP_EQ,0);
   tt_int_op(port1,OP_EQ,1);
   tt_int_op(port2,OP_EQ,65535);
@@ -945,27 +946,6 @@ test_virtaddrmap(void *data)
   ;
 }
 
-static const char *canned_data = NULL;
-static size_t canned_data_len = 0;
-
-/* Mock replacement for crypto_rand() that returns canned data from
- * canned_data above. */
-static void
-crypto_canned(char *ptr, size_t n)
-{
-  if (canned_data_len) {
-    size_t to_copy = MIN(n, canned_data_len);
-    memcpy(ptr, canned_data, to_copy);
-    canned_data += to_copy;
-    canned_data_len -= to_copy;
-    n -= to_copy;
-    ptr += to_copy;
-  }
-  if (n) {
-    crypto_rand_unmocked(ptr, n);
-  }
-}
-
 static void
 test_virtaddrmap_persist(void *data)
 {
@@ -973,6 +953,8 @@ test_virtaddrmap_persist(void *data)
   const char *a, *b, *c;
   tor_addr_t addr;
   char *ones = NULL;
+  const char *canned_data;
+  size_t canned_data_len;
 
   addressmap_init();
 
@@ -991,7 +973,7 @@ test_virtaddrmap_persist(void *data)
                 "1234567890" // the second call returns this.
                 "abcdefghij"; // the third call returns this.
   canned_data_len = 30;
-  MOCK(crypto_rand, crypto_canned);
+  testing_enable_prefilled_rng(canned_data, canned_data_len);
 
   a = addressmap_register_virtual_address(RESOLVED_TYPE_HOSTNAME,
                                           tor_strdup("quuxit.baz"));
@@ -1001,9 +983,9 @@ test_virtaddrmap_persist(void *data)
   tt_assert(b);
   tt_str_op(a, OP_EQ, "gezdgnbvgy3tqojq.virtual");
   tt_str_op(b, OP_EQ, "mfrggzdfmztwq2lk.virtual");
+  testing_disable_prefilled_rng();
 
   // Now try something to get us an ipv4 address
-  UNMOCK(crypto_rand);
   tt_int_op(0,OP_EQ, parse_virtual_addr_network("192.168.0.0/16",
                                                 AF_INET, 0, NULL));
   a = addressmap_register_virtual_address(RESOLVED_TYPE_IPV4,
@@ -1020,22 +1002,23 @@ test_virtaddrmap_persist(void *data)
 
   // Try some canned entropy and verify all the we discard duplicates,
   // addresses that end with 0, and addresses that end with 255.
-  MOCK(crypto_rand, crypto_canned);
   canned_data = "\x01\x02\x03\x04" // okay
                 "\x01\x02\x03\x04" // duplicate
                 "\x03\x04\x00\x00" // bad ending 1
                 "\x05\x05\x00\xff" // bad ending 2
                 "\x05\x06\x07\xf0"; // okay
   canned_data_len = 20;
+  testing_enable_prefilled_rng(canned_data, canned_data_len);
+
   a = addressmap_register_virtual_address(RESOLVED_TYPE_IPV4,
                                           tor_strdup("wumble.onion"));
   b = addressmap_register_virtual_address(RESOLVED_TYPE_IPV4,
                                           tor_strdup("wumpus.onion"));
   tt_str_op(a, OP_EQ, "192.168.3.4");
   tt_str_op(b, OP_EQ, "192.168.7.240");
+  testing_disable_prefilled_rng();
 
   // Now try IPv6!
-  UNMOCK(crypto_rand);
   tt_int_op(0,OP_EQ, parse_virtual_addr_network("1010:F000::/20",
                                                 AF_INET6, 0, NULL));
   a = addressmap_register_virtual_address(RESOLVED_TYPE_IPV6,
@@ -1051,7 +1034,7 @@ test_virtaddrmap_persist(void *data)
   tt_assert(!strcmpstart(b, "[1010:f"));
 
   // Try IPv6 with canned entropy, to make sure we detect duplicates.
-  MOCK(crypto_rand, crypto_canned);
+
   canned_data = "acanthopterygian" // okay
                 "cinematographist" // okay
                 "acanthopterygian" // duplicate
@@ -1060,6 +1043,8 @@ test_virtaddrmap_persist(void *data)
                 "cinematographist" // duplicate
                 "coadministration"; // okay
   canned_data_len = 16 * 7;
+  testing_enable_prefilled_rng(canned_data, canned_data_len);
+
   a = addressmap_register_virtual_address(RESOLVED_TYPE_IPV6,
                                           tor_strdup("wuffle.baz"));
   b = addressmap_register_virtual_address(RESOLVED_TYPE_IPV6,
@@ -1072,9 +1057,11 @@ test_virtaddrmap_persist(void *data)
 
   // Try address exhaustion: make sure we can actually fail if we
   // get too many already-existing addresses.
+  testing_disable_prefilled_rng();
   canned_data_len = 128*1024;
   canned_data = ones = tor_malloc(canned_data_len);
   memset(ones, 1, canned_data_len);
+  testing_enable_prefilled_rng(canned_data, canned_data_len);
   // There is some chance this one will fail if a previous random
   // allocation gave out the address already.
   a = addressmap_register_virtual_address(RESOLVED_TYPE_IPV4,
@@ -1091,7 +1078,7 @@ test_virtaddrmap_persist(void *data)
   expect_single_log_msg_containing("Ran out of virtual addresses!");
 
  done:
-  UNMOCK(crypto_rand);
+  testing_disable_prefilled_rng();
   tor_free(ones);
   addressmap_free_all();
   teardown_capture_of_logs();
diff --git a/src/test/test_bt.sh b/src/test/test_bt.sh
index df8bcb8ed..312905a4e 100755
--- a/src/test/test_bt.sh
+++ b/src/test/test_bt.sh
@@ -3,8 +3,6 @@
 
 exitcode=0
 
-ulimit -c 0
-
 export ASAN_OPTIONS="handle_segv=0:allow_user_segv_handler=1"
 "${builddir:-.}/src/test/test-bt-cl" backtraces || exit $?
 "${builddir:-.}/src/test/test-bt-cl" assert 2>&1 | "${PYTHON:-python}" "${abs_top_srcdir:-.}/src/test/bt_test.py" || exitcode="$?"
diff --git a/src/test/test_bt_cl.c b/src/test/test_bt_cl.c
index 0c15a02ee..b29c2c6cb 100644
--- a/src/test/test_bt_cl.c
+++ b/src/test/test_bt_cl.c
@@ -4,6 +4,9 @@
 #include "orconfig.h"
 #include <stdio.h>
 #include <stdlib.h>
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
 
 /* To prevent 'assert' from going away. */
 #undef TOR_COVERAGE
@@ -43,7 +46,7 @@ crash(int x)
     *(volatile int *)0 = 0;
 #endif /* defined(__clang_analyzer__) || defined(__COVERITY__) */
   } else if (crashtype == 1) {
-    tor_assert(1 == 0);
+    tor_assertf(1 == 0, "%d != %d", 1, 0);
   } else if (crashtype == -1) {
     ;
   }
@@ -88,6 +91,11 @@ main(int argc, char **argv)
     return 1;
   }
 
+#ifdef HAVE_SYS_RESOURCE_H
+  struct rlimit rlim = { .rlim_cur = 0, .rlim_max = 0 };
+  setrlimit(RLIMIT_CORE, &rlim);
+#endif
+
 #if !(defined(HAVE_EXECINFO_H) && defined(HAVE_BACKTRACE) && \
    defined(HAVE_BACKTRACE_SYMBOLS_FD) && defined(HAVE_SIGACTION))
     puts("Backtrace reporting is not supported on this platform");
diff --git a/src/test/test_channel.c b/src/test/test_channel.c
index e55b9b075..6a6bc9d81 100644
--- a/src/test/test_channel.c
+++ b/src/test/test_channel.c
@@ -598,7 +598,6 @@ test_channel_outbound_cell(void *arg)
   circuit_set_n_circid_chan(TO_CIRCUIT(circ), 42, chan);
   tt_int_op(channel_num_circuits(chan), OP_EQ, 1);
   /* Test the cmux state. */
-  tt_ptr_op(TO_CIRCUIT(circ)->n_mux, OP_EQ, chan->cmux);
   tt_int_op(circuitmux_is_circuit_attached(chan->cmux, TO_CIRCUIT(circ)),
             OP_EQ, 1);
 
@@ -1541,6 +1540,10 @@ test_channel_listener(void *arg)
   channel_listener_dump_statistics(chan, LOG_INFO);
 
  done:
+  if (chan) {
+    channel_listener_unregister(chan);
+    tor_free(chan);
+  }
   channel_free_all();
 }
 
@@ -1567,4 +1570,3 @@ struct testcase_t channel_tests[] = {
     NULL, NULL },
   END_OF_TESTCASES
 };
-
diff --git a/src/test/test_circuitbuild.c b/src/test/test_circuitbuild.c
index 27f2cd1ca..0c2309159 100644
--- a/src/test/test_circuitbuild.c
+++ b/src/test/test_circuitbuild.c
@@ -4,6 +4,8 @@
 /* See LICENSE for licensing information */
 
 #define CIRCUITBUILD_PRIVATE
+#define CIRCUITLIST_PRIVATE
+#define ENTRYNODES_PRIVATE
 
 #include "core/or/or.h"
 #include "test/test.h"
@@ -13,7 +15,11 @@
 #include "core/or/circuitbuild.h"
 #include "core/or/circuitlist.h"
 
+#include "core/or/cpath_build_state_st.h"
 #include "core/or/extend_info_st.h"
+#include "core/or/origin_circuit_st.h"
+
+#include "feature/client/entrynodes.h"
 
 /* Dummy nodes smartlist for testing */
 static smartlist_t dummy_nodes;
@@ -21,7 +27,7 @@ static smartlist_t dummy_nodes;
 static extend_info_t dummy_ei;
 
 static int
-mock_count_acceptable_nodes(smartlist_t *nodes, int direct)
+mock_count_acceptable_nodes(const smartlist_t *nodes, int direct)
 {
   (void)nodes;
 
@@ -126,10 +132,51 @@ test_new_route_len_unhandled_exit(void *arg)
   UNMOCK(count_acceptable_nodes);
 }
 
+static void
+test_upgrade_from_guard_wait(void *arg)
+{
+  circuit_t *circ = NULL;
+  origin_circuit_t *orig_circ = NULL;
+  entry_guard_t *guard = NULL;
+  smartlist_t *list = NULL;
+
+  (void) arg;
+
+  circ = dummy_origin_circuit_new(0);
+  orig_circ = TO_ORIGIN_CIRCUIT(circ);
+  tt_assert(orig_circ);
+
+  orig_circ->build_state = tor_malloc_zero(sizeof(cpath_build_state_t));
+
+  circuit_set_state(circ, CIRCUIT_STATE_GUARD_WAIT);
+
+  /* Put it in guard wait state. */
+  guard = tor_malloc_zero(sizeof(*guard));
+  guard->in_selection = get_guard_selection_info();
+
+  orig_circ->guard_state =
+    circuit_guard_state_new(guard, GUARD_CIRC_STATE_WAITING_FOR_BETTER_GUARD,
+                            NULL);
+
+  /* Mark the circuit for close. */
+  circuit_mark_for_close(circ, END_CIRC_REASON_TORPROTOCOL);
+  tt_int_op(circ->marked_for_close, OP_NE, 0);
+
+  /* We shouldn't pick the mark for close circuit. */
+  list = circuit_find_circuits_to_upgrade_from_guard_wait();
+  tt_assert(!list);
+
+ done:
+  circuit_free(circ);
+  entry_guard_free_(guard);
+}
+
 struct testcase_t circuitbuild_tests[] = {
   { "noexit", test_new_route_len_noexit, 0, NULL, NULL },
   { "safe_exit", test_new_route_len_safe_exit, 0, NULL, NULL },
   { "unsafe_exit", test_new_route_len_unsafe_exit, 0, NULL, NULL },
   { "unhandled_exit", test_new_route_len_unhandled_exit, 0, NULL, NULL },
+  { "upgrade_from_guard_wait", test_upgrade_from_guard_wait, TT_FORK,
+    NULL, NULL },
   END_OF_TESTCASES
 };
diff --git a/src/test/test_circuitpadding.c b/src/test/test_circuitpadding.c
index 09a4c9a0c..25f8fd311 100644
--- a/src/test/test_circuitpadding.c
+++ b/src/test/test_circuitpadding.c
@@ -1,14 +1,17 @@
 #define TOR_CHANNEL_INTERNAL_
 #define TOR_TIMERS_PRIVATE
 #define CIRCUITPADDING_PRIVATE
+#define CIRCUITPADDING_MACHINES_PRIVATE
 #define NETWORKSTATUS_PRIVATE
+#define CRYPT_PATH_PRIVATE
 
 #include "core/or/or.h"
-#include "test.h"
+#include "test/test.h"
 #include "lib/testsupport/testsupport.h"
 #include "core/or/connection_or.h"
 #include "core/or/channel.h"
 #include "core/or/channeltls.h"
+#include "core/or/crypt_path.h"
 #include <event.h>
 #include "lib/evloop/compat_libevent.h"
 #include "lib/time/compat_time.h"
@@ -17,6 +20,8 @@
 #include "core/or/circuitlist.h"
 #include "core/or/circuitbuild.h"
 #include "core/or/circuitpadding.h"
+#include "core/or/circuitpadding_machines.h"
+#include "core/mainloop/netstatus.h"
 #include "core/crypto/relay_crypto.h"
 #include "core/or/protover.h"
 #include "feature/nodelist/nodelist.h"
@@ -31,6 +36,8 @@
 #include "core/or/or_circuit_st.h"
 #include "core/or/origin_circuit_st.h"
 
+#include "test/rng_test_helpers.h"
+
 /* Start our monotime mocking at 1 second past whatever monotime_init()
  * thought the actual wall clock time was, for platforms with bad resolution
  * and weird timevalues during monotime_init() before mocking. */
@@ -38,6 +45,7 @@
                                TOR_NSEC_PER_USEC*TOR_USEC_PER_SEC)
 
 extern smartlist_t *connection_array;
+void circuit_expire_old_circuits_clientside(void);
 
 circid_t get_unique_circ_id_by_chan(channel_t *chan);
 void helper_create_basic_machine(void);
@@ -52,6 +60,7 @@ void test_circuitpadding_conditions(void *arg);
 void test_circuitpadding_serialize(void *arg);
 void test_circuitpadding_rtt(void *arg);
 void test_circuitpadding_tokens(void *arg);
+void test_circuitpadding_state_length(void *arg);
 
 static void
 simulate_single_hop_extend(circuit_t *client, circuit_t *mid_relay,
@@ -81,10 +90,10 @@ static void
 nodes_init(void)
 {
   padding_node.rs = tor_malloc_zero(sizeof(routerstatus_t));
-  padding_node.rs->pv.supports_padding = 1;
+  padding_node.rs->pv.supports_hs_setup_padding = 1;
 
   non_padding_node.rs = tor_malloc_zero(sizeof(routerstatus_t));
-  non_padding_node.rs->pv.supports_padding = 0;
+  non_padding_node.rs->pv.supports_hs_setup_padding = 0;
 }
 
 static void
@@ -107,6 +116,15 @@ node_get_by_id_mock(const char *identity_digest)
   return NULL;
 }
 
+static const node_t *
+circuit_get_nth_node_mock(origin_circuit_t *circ, int hop)
+{
+  (void) circ;
+  (void) hop;
+
+  return &padding_node;
+}
+
 static or_circuit_t *
 new_fake_orcirc(channel_t *nchan, channel_t *pchan)
 {
@@ -121,7 +139,6 @@ new_fake_orcirc(channel_t *nchan, channel_t *pchan)
 
   //circ->n_chan = nchan;
   circ->n_circ_id = get_unique_circ_id_by_chan(nchan);
-  circ->n_mux = NULL; /* ?? */
   cell_queue_init(&(circ->n_chan_cells));
   circ->n_hop = NULL;
   circ->streams_blocked_on_n_chan = 0;
@@ -143,12 +160,12 @@ new_fake_orcirc(channel_t *nchan, channel_t *pchan)
   circuit_set_n_circid_chan(circ, circ->n_circ_id, nchan);
 
   memset(&tmp_cpath, 0, sizeof(tmp_cpath));
-  if (circuit_init_cpath_crypto(&tmp_cpath, whatevs_key,
+  if (cpath_init_circuit_crypto(&tmp_cpath, whatevs_key,
                                 sizeof(whatevs_key), 0, 0)<0) {
     log_warn(LD_BUG,"Circuit initialization failed");
     return NULL;
   }
-  orcirc->crypto = tmp_cpath.crypto;
+  orcirc->crypto = tmp_cpath.pvt_crypto;
 
   return orcirc;
 }
@@ -298,6 +315,7 @@ test_circuitpadding_rtt(void *arg)
 
   MOCK(circuitmux_attach_circuit, circuitmux_attach_circuit_mock);
   MOCK(circpad_send_command_to_hop, circpad_send_command_to_hop_mock);
+  testing_enable_reproducible_rng();
 
   dummy_channel.cmux = circuitmux_alloc();
   relay_side = TO_CIRCUIT(new_fake_orcirc(&dummy_channel, &dummy_channel));
@@ -327,12 +345,12 @@ test_circuitpadding_rtt(void *arg)
   relay_side->padding_info[0] = circpad_circuit_machineinfo_new(client_side,0);
 
   /* Test 1: Test measuring RTT */
-  circpad_cell_event_nonpadding_received((circuit_t*)relay_side);
+  circpad_cell_event_nonpadding_received(relay_side);
   tt_u64_op(relay_side->padding_info[0]->last_received_time_usec, OP_NE, 0);
 
   timers_advance_and_run(20);
 
-  circpad_cell_event_nonpadding_sent((circuit_t*)relay_side);
+  circpad_cell_event_nonpadding_sent(relay_side);
   tt_u64_op(relay_side->padding_info[0]->last_received_time_usec, OP_EQ, 0);
 
   tt_int_op(relay_side->padding_info[0]->rtt_estimate_usec, OP_GE, 19000);
@@ -341,14 +359,14 @@ test_circuitpadding_rtt(void *arg)
             OP_EQ,
             relay_side->padding_info[0]->rtt_estimate_usec+
             circpad_machine_current_state(
-             relay_side->padding_info[0])->start_usec);
+             relay_side->padding_info[0])->histogram_edges[0]);
 
-  circpad_cell_event_nonpadding_received((circuit_t*)relay_side);
-  circpad_cell_event_nonpadding_received((circuit_t*)relay_side);
+  circpad_cell_event_nonpadding_received(relay_side);
+  circpad_cell_event_nonpadding_received(relay_side);
   tt_u64_op(relay_side->padding_info[0]->last_received_time_usec, OP_NE, 0);
   timers_advance_and_run(20);
-  circpad_cell_event_nonpadding_sent((circuit_t*)relay_side);
-  circpad_cell_event_nonpadding_sent((circuit_t*)relay_side);
+  circpad_cell_event_nonpadding_sent(relay_side);
+  circpad_cell_event_nonpadding_sent(relay_side);
   tt_u64_op(relay_side->padding_info[0]->last_received_time_usec, OP_EQ, 0);
 
   tt_int_op(relay_side->padding_info[0]->rtt_estimate_usec, OP_GE, 20000);
@@ -357,15 +375,15 @@ test_circuitpadding_rtt(void *arg)
             OP_EQ,
             relay_side->padding_info[0]->rtt_estimate_usec+
             circpad_machine_current_state(
-             relay_side->padding_info[0])->start_usec);
+             relay_side->padding_info[0])->histogram_edges[0]);
 
   /* Test 2: Termination of RTT measurement (from the previous test) */
   tt_int_op(relay_side->padding_info[0]->stop_rtt_update, OP_EQ, 1);
   rtt_estimate = relay_side->padding_info[0]->rtt_estimate_usec;
 
-  circpad_cell_event_nonpadding_received((circuit_t*)relay_side);
+  circpad_cell_event_nonpadding_received(relay_side);
   timers_advance_and_run(4);
-  circpad_cell_event_nonpadding_sent((circuit_t*)relay_side);
+  circpad_cell_event_nonpadding_sent(relay_side);
 
   tt_int_op(relay_side->padding_info[0]->rtt_estimate_usec, OP_EQ,
             rtt_estimate);
@@ -375,14 +393,14 @@ test_circuitpadding_rtt(void *arg)
             OP_EQ,
             relay_side->padding_info[0]->rtt_estimate_usec+
             circpad_machine_current_state(
-             relay_side->padding_info[0])->start_usec);
+             relay_side->padding_info[0])->histogram_edges[0]);
 
   /* Test 3: Make sure client side machine properly ignores RTT */
-  circpad_cell_event_nonpadding_received((circuit_t*)client_side);
+  circpad_cell_event_nonpadding_received(client_side);
   tt_u64_op(client_side->padding_info[0]->last_received_time_usec, OP_EQ, 0);
 
   timers_advance_and_run(20);
-  circpad_cell_event_nonpadding_sent((circuit_t*)client_side);
+  circpad_cell_event_nonpadding_sent(client_side);
   tt_u64_op(client_side->padding_info[0]->last_received_time_usec, OP_EQ, 0);
 
   tt_int_op(client_side->padding_info[0]->rtt_estimate_usec, OP_EQ, 0);
@@ -391,7 +409,7 @@ test_circuitpadding_rtt(void *arg)
   tt_int_op(circpad_histogram_bin_to_usec(client_side->padding_info[0], 0),
             OP_EQ,
             circpad_machine_current_state(
-                client_side->padding_info[0])->start_usec);
+                client_side->padding_info[0])->histogram_edges[0]);
  done:
   free_fake_orcirc(relay_side);
   circuitmux_detach_all_circuits(dummy_channel.cmux, NULL);
@@ -401,6 +419,7 @@ test_circuitpadding_rtt(void *arg)
   UNMOCK(circuit_package_relay_cell);
   UNMOCK(circuitmux_attach_circuit);
   tor_free(circ_client_machine.states);
+  testing_disable_reproducible_rng();
 
   return;
 }
@@ -411,8 +430,11 @@ helper_create_basic_machine(void)
   /* Start, burst */
   circpad_machine_states_init(&circ_client_machine, 2);
 
+  circ_client_machine.name = "basic";
+
   circ_client_machine.states[CIRCPAD_STATE_START].
       next_state[CIRCPAD_EVENT_NONPADDING_RECV] = CIRCPAD_STATE_BURST;
+  circ_client_machine.states[CIRCPAD_STATE_START].use_rtt_estimate = 1;
 
   circ_client_machine.states[CIRCPAD_STATE_BURST].
       next_state[CIRCPAD_EVENT_PADDING_RECV] = CIRCPAD_STATE_BURST;
@@ -422,19 +444,23 @@ helper_create_basic_machine(void)
   circ_client_machine.states[CIRCPAD_STATE_BURST].
       next_state[CIRCPAD_EVENT_NONPADDING_SENT] = CIRCPAD_STATE_CANCEL;
 
-  // FIXME: Is this what we want?
   circ_client_machine.states[CIRCPAD_STATE_BURST].token_removal =
       CIRCPAD_TOKEN_REMOVAL_HIGHER;
 
-  // FIXME: Tune this histogram
   circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_len = 5;
-  circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 500;
-  circ_client_machine.states[CIRCPAD_STATE_BURST].range_usec = 1000000;
+
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[0] = 500;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[1] = 2500;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[2] = 5000;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[3] = 10000;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[4] = 20000;
+
   circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[0] = 1;
   circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[1] = 0;
   circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[2] = 2;
   circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[3] = 2;
   circ_client_machine.states[CIRCPAD_STATE_BURST].histogram[4] = 2;
+
   circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_total_tokens = 7;
   circ_client_machine.states[CIRCPAD_STATE_BURST].use_rtt_estimate = 1;
 
@@ -466,15 +492,25 @@ helper_create_machine_with_big_histogram(circpad_removal_t removal_strategy)
   burst_state->token_removal = CIRCPAD_TOKEN_REMOVAL_HIGHER;
 
   burst_state->histogram_len = BIG_HISTOGRAM_LEN;
-  burst_state->start_usec = 0;
-  burst_state->range_usec = 1000;
 
   int n_tokens = 0;
-  for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
+  int i;
+  for (i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
     burst_state->histogram[i] = tokens_per_bin;
     n_tokens += tokens_per_bin;
   }
 
+  burst_state->histogram_edges[0] = 0;
+  burst_state->histogram_edges[1] = 1;
+  burst_state->histogram_edges[2] = 7;
+  burst_state->histogram_edges[3] = 15;
+  burst_state->histogram_edges[4] = 31;
+  burst_state->histogram_edges[5] = 62;
+  burst_state->histogram_edges[6] = 125;
+  burst_state->histogram_edges[7] = 250;
+  burst_state->histogram_edges[8] = 500;
+  burst_state->histogram_edges[9] = 1000;
+
   burst_state->histogram_total_tokens = n_tokens;
   burst_state->length_dist.type = CIRCPAD_DIST_UNIFORM;
   burst_state->length_dist.param1 = n_tokens;
@@ -486,7 +522,7 @@ helper_create_machine_with_big_histogram(circpad_removal_t removal_strategy)
 }
 
 static circpad_decision_t
-circpad_machine_schedule_padding_mock(circpad_machine_state_t *mi)
+circpad_machine_schedule_padding_mock(circpad_machine_runtime_t *mi)
 {
   (void)mi;
   return 0;
@@ -502,15 +538,16 @@ mock_monotime_absolute_usec(void)
 static void
 test_circuitpadding_token_removal_higher(void *arg)
 {
-  circpad_machine_state_t *mi;
+  circpad_machine_runtime_t *mi;
   (void)arg;
 
   /* Mock it up */
   MOCK(monotime_absolute_usec, mock_monotime_absolute_usec);
   MOCK(circpad_machine_schedule_padding,circpad_machine_schedule_padding_mock);
+  testing_enable_reproducible_rng();
 
   /* Setup test environment (time etc.) */
-  client_side = (circuit_t *)origin_circuit_new();
+  client_side = TO_CIRCUIT(origin_circuit_new());
   client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
   monotime_enable_test_mocking();
 
@@ -521,7 +558,7 @@ test_circuitpadding_token_removal_higher(void *arg)
     circpad_circuit_machineinfo_new(client_side, 0);
 
   /* move the machine to the right state */
-  circpad_cell_event_nonpadding_received((circuit_t*)client_side);
+  circpad_cell_event_nonpadding_received(client_side);
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
 
@@ -535,12 +572,20 @@ test_circuitpadding_token_removal_higher(void *arg)
 
   /* Test left boundaries of each histogram bin: */
   const circpad_delay_t bin_left_bounds[] =
-    {0, 1, 7, 15, 31, 62, 125, 250, 500, CIRCPAD_DELAY_INFINITE};
-  for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
+    {0, 1,    7,  15,  31,  62,  125, 250, 500, 1000, CIRCPAD_DELAY_INFINITE};
+  for (int i = 0; i <= BIG_HISTOGRAM_LEN ; i++) {
     tt_uint_op(bin_left_bounds[i], OP_EQ,
                circpad_histogram_bin_to_usec(mi, i));
   }
 
+  /* Test right boundaries of each histogram bin: */
+  const circpad_delay_t bin_right_bounds[] =
+    {0,    6,  14,  30,  61,  124, 249, 499, 999, CIRCPAD_DELAY_INFINITE-1};
+  for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
+    tt_uint_op(bin_right_bounds[i], OP_EQ,
+               histogram_get_bin_upper_bound(mi, i));
+  }
+
   /* Check that all bins have two tokens right now */
   for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
     tt_int_op(mi->histogram[i], OP_EQ, 2);
@@ -562,12 +607,12 @@ test_circuitpadding_token_removal_higher(void *arg)
     tt_int_op(mi->histogram[bin_to_remove], OP_EQ, 2);
 
     mi->padding_scheduled_at_usec = current_time - 57;
-    circpad_machine_remove_token(mi);
+    circpad_cell_event_nonpadding_sent(client_side);
 
     tt_int_op(mi->histogram[bin_to_remove], OP_EQ, 1);
 
     mi->padding_scheduled_at_usec = current_time - 57;
-    circpad_machine_remove_token(mi);
+    circpad_cell_event_nonpadding_sent(client_side);
 
     /* Test that we cleaned out this bin. Don't do this in the case of the last
        bin since the tokens will get refilled */
@@ -584,30 +629,32 @@ test_circuitpadding_token_removal_higher(void *arg)
   /* Test below the lowest bin, for coverage */
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
-  circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100;
-  mi->padding_scheduled_at_usec = current_time - 1;
-  circpad_machine_remove_token(mi);
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[0] = 100;
+  mi->padding_scheduled_at_usec = current_time;
+  circpad_cell_event_nonpadding_sent(client_side);
   tt_int_op(mi->histogram[0], OP_EQ, 1);
 
  done:
   free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
   monotime_disable_test_mocking();
   tor_free(circ_client_machine.states);
+  testing_disable_reproducible_rng();
 }
 
 /** Test lower token removal strategy by bin  */
 static void
 test_circuitpadding_token_removal_lower(void *arg)
 {
-  circpad_machine_state_t *mi;
+  circpad_machine_runtime_t *mi;
   (void)arg;
 
   /* Mock it up */
   MOCK(monotime_absolute_usec, mock_monotime_absolute_usec);
   MOCK(circpad_machine_schedule_padding,circpad_machine_schedule_padding_mock);
+  testing_enable_reproducible_rng();
 
   /* Setup test environment (time etc.) */
-  client_side = (circuit_t *)origin_circuit_new();
+  client_side = TO_CIRCUIT(origin_circuit_new());
   client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
   monotime_enable_test_mocking();
 
@@ -618,7 +665,7 @@ test_circuitpadding_token_removal_lower(void *arg)
     circpad_circuit_machineinfo_new(client_side, 0);
 
   /* move the machine to the right state */
-  circpad_cell_event_nonpadding_received((circuit_t*)client_side);
+  circpad_cell_event_nonpadding_received(client_side);
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
 
@@ -632,8 +679,8 @@ test_circuitpadding_token_removal_lower(void *arg)
 
   /* Test left boundaries of each histogram bin: */
   const circpad_delay_t bin_left_bounds[] =
-    {0, 1, 7, 15, 31, 62, 125, 250, 500, CIRCPAD_DELAY_INFINITE};
-  for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
+    {0, 1,    7,  15,  31,  62,  125, 250, 500, 1000, CIRCPAD_DELAY_INFINITE};
+  for (int i = 0; i <= BIG_HISTOGRAM_LEN ; i++) {
     tt_uint_op(bin_left_bounds[i], OP_EQ,
                circpad_histogram_bin_to_usec(mi, i));
   }
@@ -659,12 +706,12 @@ test_circuitpadding_token_removal_lower(void *arg)
     tt_int_op(mi->histogram[bin_to_remove], OP_EQ, 2);
 
     mi->padding_scheduled_at_usec = current_time - 57;
-    circpad_machine_remove_token(mi);
+    circpad_cell_event_nonpadding_sent(client_side);
 
     tt_int_op(mi->histogram[bin_to_remove], OP_EQ, 1);
 
     mi->padding_scheduled_at_usec = current_time - 57;
-    circpad_machine_remove_token(mi);
+    circpad_cell_event_nonpadding_sent(client_side);
 
     /* Test that we cleaned out this bin. Don't do this in the case of the last
        bin since the tokens will get refilled */
@@ -681,30 +728,33 @@ test_circuitpadding_token_removal_lower(void *arg)
   /* Test above the highest bin, for coverage */
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
-  circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].
+    histogram_edges[BIG_HISTOGRAM_LEN-2] = 100;
   mi->padding_scheduled_at_usec = current_time - 29202;
-  circpad_machine_remove_token(mi);
+  circpad_cell_event_nonpadding_sent(client_side);
   tt_int_op(mi->histogram[BIG_HISTOGRAM_LEN-2], OP_EQ, 1);
 
  done:
   free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
   monotime_disable_test_mocking();
   tor_free(circ_client_machine.states);
+  testing_disable_reproducible_rng();
 }
 
 /** Test closest token removal strategy by bin  */
 static void
 test_circuitpadding_closest_token_removal(void *arg)
 {
-  circpad_machine_state_t *mi;
+  circpad_machine_runtime_t *mi;
   (void)arg;
 
   /* Mock it up */
   MOCK(monotime_absolute_usec, mock_monotime_absolute_usec);
   MOCK(circpad_machine_schedule_padding,circpad_machine_schedule_padding_mock);
+  testing_enable_reproducible_rng();
 
   /* Setup test environment (time etc.) */
-  client_side = (circuit_t *)origin_circuit_new();
+  client_side = TO_CIRCUIT(origin_circuit_new());
   client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
   monotime_enable_test_mocking();
 
@@ -715,7 +765,7 @@ test_circuitpadding_closest_token_removal(void *arg)
     circpad_circuit_machineinfo_new(client_side, 0);
 
   /* move the machine to the right state */
-  circpad_cell_event_nonpadding_received((circuit_t*)client_side);
+  circpad_cell_event_nonpadding_received(client_side);
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
 
@@ -729,8 +779,8 @@ test_circuitpadding_closest_token_removal(void *arg)
 
   /* Test left boundaries of each histogram bin: */
   const circpad_delay_t bin_left_bounds[] =
-    {0, 1, 7, 15, 31, 62, 125, 250, 500, CIRCPAD_DELAY_INFINITE};
-  for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
+    {0, 1,    7,  15,  31,  62,  125, 250, 500, 1000, CIRCPAD_DELAY_INFINITE};
+  for (int i = 0; i <= BIG_HISTOGRAM_LEN ; i++) {
     tt_uint_op(bin_left_bounds[i], OP_EQ,
                circpad_histogram_bin_to_usec(mi, i));
   }
@@ -755,12 +805,12 @@ test_circuitpadding_closest_token_removal(void *arg)
     tt_int_op(mi->histogram[bin_to_remove], OP_EQ, 2);
 
     mi->padding_scheduled_at_usec = current_time - 57;
-    circpad_machine_remove_token(mi);
+    circpad_cell_event_nonpadding_sent(client_side);
 
     tt_int_op(mi->histogram[bin_to_remove], OP_EQ, 1);
 
     mi->padding_scheduled_at_usec = current_time - 57;
-    circpad_machine_remove_token(mi);
+    circpad_cell_event_nonpadding_sent(client_side);
 
     /* Test that we cleaned out this bin. Don't do this in the case of the last
        bin since the tokens will get refilled */
@@ -777,39 +827,42 @@ test_circuitpadding_closest_token_removal(void *arg)
   /* Test below the lowest bin, for coverage */
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
-  circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[0] = 100;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[1] = 101;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[2] = 120;
   mi->padding_scheduled_at_usec = current_time - 102;
   mi->histogram[0] = 0;
-  circpad_machine_remove_token(mi);
+  circpad_cell_event_nonpadding_sent(client_side);
   tt_int_op(mi->histogram[1], OP_EQ, 1);
 
   /* Test above the highest bin, for coverage */
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
-  circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100;
   mi->padding_scheduled_at_usec = current_time - 29202;
-  circpad_machine_remove_token(mi);
+  circpad_cell_event_nonpadding_sent(client_side);
   tt_int_op(mi->histogram[BIG_HISTOGRAM_LEN-2], OP_EQ, 1);
 
  done:
   free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
   monotime_disable_test_mocking();
   tor_free(circ_client_machine.states);
+  testing_disable_reproducible_rng();
 }
 
 /** Test closest token removal strategy with usec  */
 static void
 test_circuitpadding_closest_token_removal_usec(void *arg)
 {
-  circpad_machine_state_t *mi;
+  circpad_machine_runtime_t *mi;
   (void)arg;
 
   /* Mock it up */
   MOCK(monotime_absolute_usec, mock_monotime_absolute_usec);
   MOCK(circpad_machine_schedule_padding,circpad_machine_schedule_padding_mock);
+  testing_enable_reproducible_rng();
 
   /* Setup test environment (time etc.) */
-  client_side = (circuit_t *)origin_circuit_new();
+  client_side = TO_CIRCUIT(origin_circuit_new());
   client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
   monotime_enable_test_mocking();
 
@@ -820,7 +873,7 @@ test_circuitpadding_closest_token_removal_usec(void *arg)
     circpad_circuit_machineinfo_new(client_side, 0);
 
   /* move the machine to the right state */
-  circpad_cell_event_nonpadding_received((circuit_t*)client_side);
+  circpad_cell_event_nonpadding_received(client_side);
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
 
@@ -834,8 +887,8 @@ test_circuitpadding_closest_token_removal_usec(void *arg)
 
   /* Test left boundaries of each histogram bin: */
   const circpad_delay_t bin_left_bounds[] =
-    {0, 1, 7, 15, 31, 62, 125, 250, 500, CIRCPAD_DELAY_INFINITE};
-  for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
+    {0, 1,    7,  15,  31,  62,  125, 250, 500, 1000, CIRCPAD_DELAY_INFINITE};
+  for (int i = 0; i <= BIG_HISTOGRAM_LEN ; i++) {
     tt_uint_op(bin_left_bounds[i], OP_EQ,
                circpad_histogram_bin_to_usec(mi, i));
   }
@@ -863,12 +916,12 @@ test_circuitpadding_closest_token_removal_usec(void *arg)
     tt_int_op(mi->histogram[bin_to_remove], OP_EQ, 2);
 
     mi->padding_scheduled_at_usec = current_time - 57;
-    circpad_machine_remove_token(mi);
+    circpad_cell_event_nonpadding_sent(client_side);
 
     tt_int_op(mi->histogram[bin_to_remove], OP_EQ, 1);
 
     mi->padding_scheduled_at_usec = current_time - 57;
-    circpad_machine_remove_token(mi);
+    circpad_cell_event_nonpadding_sent(client_side);
 
     /* Test that we cleaned out this bin. Don't do this in the case of the last
        bin since the tokens will get refilled */
@@ -885,39 +938,44 @@ test_circuitpadding_closest_token_removal_usec(void *arg)
   /* Test below the lowest bin, for coverage */
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
-  circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[0] = 100;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[1] = 101;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].histogram_edges[2] = 120;
   mi->padding_scheduled_at_usec = current_time - 102;
   mi->histogram[0] = 0;
-  circpad_machine_remove_token(mi);
+  circpad_cell_event_nonpadding_sent(client_side);
   tt_int_op(mi->histogram[1], OP_EQ, 1);
 
   /* Test above the highest bin, for coverage */
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
-  circ_client_machine.states[CIRCPAD_STATE_BURST].start_usec = 100;
+  circ_client_machine.states[CIRCPAD_STATE_BURST].
+    histogram_edges[BIG_HISTOGRAM_LEN-2] = 100;
   mi->padding_scheduled_at_usec = current_time - 29202;
-  circpad_machine_remove_token(mi);
+  circpad_cell_event_nonpadding_sent(client_side);
   tt_int_op(mi->histogram[BIG_HISTOGRAM_LEN-2], OP_EQ, 1);
 
  done:
   free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
   monotime_disable_test_mocking();
   tor_free(circ_client_machine.states);
+  testing_disable_reproducible_rng();
 }
 
 /** Test closest token removal strategy with usec  */
 static void
 test_circuitpadding_token_removal_exact(void *arg)
 {
-  circpad_machine_state_t *mi;
+  circpad_machine_runtime_t *mi;
   (void)arg;
 
   /* Mock it up */
   MOCK(monotime_absolute_usec, mock_monotime_absolute_usec);
   MOCK(circpad_machine_schedule_padding,circpad_machine_schedule_padding_mock);
+  testing_enable_reproducible_rng();
 
   /* Setup test environment (time etc.) */
-  client_side = (circuit_t *)origin_circuit_new();
+  client_side = TO_CIRCUIT(origin_circuit_new());
   client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
   monotime_enable_test_mocking();
 
@@ -928,7 +986,7 @@ test_circuitpadding_token_removal_exact(void *arg)
     circpad_circuit_machineinfo_new(client_side, 0);
 
   /* move the machine to the right state */
-  circpad_cell_event_nonpadding_received((circuit_t*)client_side);
+  circpad_cell_event_nonpadding_received(client_side);
   tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
             CIRCPAD_STATE_BURST);
 
@@ -942,16 +1000,16 @@ test_circuitpadding_token_removal_exact(void *arg)
   /* Ensure that we will clear out bin #4 with this usec */
   mi->padding_scheduled_at_usec = current_time - 57;
   tt_int_op(mi->histogram[4], OP_EQ, 2);
-  circpad_machine_remove_token(mi);
+  circpad_cell_event_nonpadding_sent(client_side);
   mi->padding_scheduled_at_usec = current_time - 57;
   tt_int_op(mi->histogram[4], OP_EQ, 1);
-  circpad_machine_remove_token(mi);
+  circpad_cell_event_nonpadding_sent(client_side);
   tt_int_op(mi->histogram[4], OP_EQ, 0);
 
   /* Ensure that we will not remove any other tokens even tho we try to, since
    * this is what the exact strategy dictates */
   mi->padding_scheduled_at_usec = current_time - 57;
-  circpad_machine_remove_token(mi);
+  circpad_cell_event_nonpadding_sent(client_side);
   for (int i = 0; i < BIG_HISTOGRAM_LEN ; i++) {
     if (i != 4) {
       tt_int_op(mi->histogram[i], OP_EQ, 2);
@@ -962,6 +1020,7 @@ test_circuitpadding_token_removal_exact(void *arg)
   free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
   monotime_disable_test_mocking();
   tor_free(circ_client_machine.states);
+  testing_disable_reproducible_rng();
 }
 
 #undef BIG_HISTOGRAM_LEN
@@ -970,10 +1029,12 @@ void
 test_circuitpadding_tokens(void *arg)
 {
   const circpad_state_t *state;
-  circpad_machine_state_t *mi;
+  circpad_machine_runtime_t *mi;
   int64_t actual_mocked_monotime_start;
   (void)arg;
 
+  testing_enable_reproducible_rng();
+
   /** Test plan:
    *
    * 1. Test symmetry between bin_to_usec and usec_to_bin
@@ -1004,6 +1065,9 @@ test_circuitpadding_tokens(void *arg)
   monotime_coarse_set_mock_time_nsec(actual_mocked_monotime_start);
   curr_mocked_time = actual_mocked_monotime_start;
 
+  /* This is needed so that we are not considered to be dormant */
+  note_user_activity(20);
+
   timers_initialize();
 
   helper_create_basic_machine();
@@ -1014,8 +1078,8 @@ test_circuitpadding_tokens(void *arg)
   mi = client_side->padding_info[0];
 
   // Pretend a non-padding cell was sent
-  circpad_cell_event_nonpadding_received((circuit_t*)client_side);
-  circpad_cell_event_nonpadding_sent((circuit_t*)client_side);
+  circpad_cell_event_nonpadding_received(client_side);
+  circpad_cell_event_nonpadding_sent(client_side);
   /* We have to save the infinity bin because one inf delay
    * could have been chosen when we transition to burst */
   circpad_hist_token_t inf_bin = mi->histogram[4];
@@ -1052,7 +1116,7 @@ test_circuitpadding_tokens(void *arg)
 
   // Test 1: converting usec->bin->usec->bin
   // Bin 0+1 have different semantics.
-  for (circpad_delay_t i = 0; i <= state->start_usec+1; i++) {
+  for (circpad_delay_t i = 0; i <= state->histogram_edges[0]; i++) {
     int bin = circpad_histogram_usec_to_bin(client_side->padding_info[0],
                                             i);
     circpad_delay_t usec =
@@ -1062,8 +1126,9 @@ test_circuitpadding_tokens(void *arg)
     tt_int_op(bin, OP_EQ, bin2);
     tt_int_op(i, OP_LE, usec);
   }
-  for (circpad_delay_t i = state->start_usec+1;
-           i <= state->start_usec + state->range_usec; i++) {
+  for (circpad_delay_t i = state->histogram_edges[0]+1;
+       i <= state->histogram_edges[0] +
+         state->histogram_edges[state->histogram_len-2]; i++) {
     int bin = circpad_histogram_usec_to_bin(client_side->padding_info[0],
                                             i);
     circpad_delay_t usec =
@@ -1116,19 +1181,18 @@ test_circuitpadding_tokens(void *arg)
   {
     tt_int_op(mi->histogram[0], OP_EQ, 0);
     mi->histogram[0] = 1;
-    circpad_machine_remove_higher_token(mi,
-         state->start_usec/2);
+    circpad_machine_remove_higher_token(mi, state->histogram_edges[0]/2);
     tt_int_op(mi->histogram[0], OP_EQ, 0);
   }
 
   /* Drain the infinity bin and cause a refill */
   while (inf_bin != 0) {
     tt_int_op(mi->histogram[4], OP_EQ, inf_bin);
-    circpad_cell_event_nonpadding_received((circuit_t*)client_side);
+    circpad_cell_event_nonpadding_received(client_side);
     inf_bin--;
   }
 
-  circpad_cell_event_nonpadding_sent((circuit_t*)client_side);
+  circpad_cell_event_nonpadding_sent(client_side);
 
   // We should have refilled here.
   tt_int_op(mi->histogram[4], OP_EQ, 2);
@@ -1136,8 +1200,7 @@ test_circuitpadding_tokens(void *arg)
   /* 3.a. Bin 0 */
   {
     tt_int_op(mi->histogram[0], OP_EQ, 1);
-    circpad_machine_remove_higher_token(mi,
-         state->start_usec/2);
+    circpad_machine_remove_higher_token(mi, state->histogram_edges[0]/2);
     tt_int_op(mi->histogram[0], OP_EQ, 0);
   }
 
@@ -1225,6 +1288,7 @@ test_circuitpadding_tokens(void *arg)
   free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
   monotime_disable_test_mocking();
   tor_free(circ_client_machine.states);
+  testing_disable_reproducible_rng();
 }
 
 void
@@ -1252,11 +1316,12 @@ test_circuitpadding_wronghop(void *arg)
   /* Mock this function so that our cell counting tests don't get confused by
    * padding that gets sent by scheduled timers. */
   MOCK(circpad_machine_schedule_padding,circpad_machine_schedule_padding_mock);
+  testing_enable_reproducible_rng();
 
-  client_side = (circuit_t *)origin_circuit_new();
+  client_side = TO_CIRCUIT(origin_circuit_new());
   dummy_channel.cmux = circuitmux_alloc();
-  relay_side = (circuit_t *)new_fake_orcirc(&dummy_channel,
-                                            &dummy_channel);
+  relay_side = TO_CIRCUIT(new_fake_orcirc(&dummy_channel,
+                                            &dummy_channel));
   orig_client = TO_ORIGIN_CIRCUIT(client_side);
 
   relay_side->purpose = CIRCUIT_PURPOSE_OR;
@@ -1374,9 +1439,9 @@ test_circuitpadding_wronghop(void *arg)
   free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
   free_fake_orcirc(relay_side);
 
-  client_side = (circuit_t *)origin_circuit_new();
-  relay_side = (circuit_t *)new_fake_orcirc(&dummy_channel,
-                                            &dummy_channel);
+  client_side = TO_CIRCUIT(origin_circuit_new());
+  relay_side = TO_CIRCUIT(new_fake_orcirc(&dummy_channel,
+                                            &dummy_channel));
   relay_side->purpose = CIRCUIT_PURPOSE_OR;
   client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
 
@@ -1425,6 +1490,7 @@ test_circuitpadding_wronghop(void *arg)
   UNMOCK(circuit_package_relay_cell);
   UNMOCK(circuitmux_attach_circuit);
   nodes_free();
+  testing_disable_reproducible_rng();
 }
 
 void
@@ -1570,10 +1636,10 @@ simulate_single_hop_extend(circuit_t *client, circuit_t *mid_relay,
   tor_addr_t addr;
 
   // Pretend a non-padding cell was sent
-  circpad_cell_event_nonpadding_sent((circuit_t*)client);
+  circpad_cell_event_nonpadding_sent(client);
 
   // Receive extend cell at middle
-  circpad_cell_event_nonpadding_received((circuit_t*)mid_relay);
+  circpad_cell_event_nonpadding_received(mid_relay);
 
   // Advance time a tiny bit so we can calculate an RTT
   curr_mocked_time += 10 * TOR_NSEC_PER_MSEC;
@@ -1581,14 +1647,14 @@ simulate_single_hop_extend(circuit_t *client, circuit_t *mid_relay,
   monotime_set_mock_time_nsec(curr_mocked_time);
 
   // Receive extended cell at middle
-  circpad_cell_event_nonpadding_sent((circuit_t*)mid_relay);
+  circpad_cell_event_nonpadding_sent(mid_relay);
 
   // Receive extended cell at first hop
-  circpad_cell_event_nonpadding_received((circuit_t*)client);
+  circpad_cell_event_nonpadding_received(client);
 
   // Add a hop to cpath
   crypt_path_t *hop = tor_malloc_zero(sizeof(crypt_path_t));
-  onion_append_to_cpath(&TO_ORIGIN_CIRCUIT(client)->cpath, hop);
+  cpath_extend_linked_list(&TO_ORIGIN_CIRCUIT(client)->cpath, hop);
 
   hop->magic = CRYPT_PATH_MAGIC;
   hop->state = CPATH_STATE_OPEN;
@@ -1602,7 +1668,7 @@ simulate_single_hop_extend(circuit_t *client, circuit_t *mid_relay,
           digest, NULL, NULL, NULL,
           &addr, padding);
 
-  circuit_init_cpath_crypto(hop, whatevs_key, sizeof(whatevs_key), 0, 0);
+  cpath_init_circuit_crypto(hop, whatevs_key, sizeof(whatevs_key), 0, 0);
 
   hop->package_window = circuit_initial_package_window();
   hop->deliver_window = CIRCWINDOW_START;
@@ -1612,7 +1678,7 @@ simulate_single_hop_extend(circuit_t *client, circuit_t *mid_relay,
 }
 
 static circpad_machine_spec_t *
-helper_create_conditional_machine(void)
+helper_create_length_machine(void)
 {
   circpad_machine_spec_t *ret =
     tor_malloc_zero(sizeof(circpad_machine_spec_t));
@@ -1629,15 +1695,69 @@ helper_create_conditional_machine(void)
   ret->states[CIRCPAD_STATE_BURST].
       next_state[CIRCPAD_EVENT_LENGTH_COUNT] = CIRCPAD_STATE_END;
 
+  ret->states[CIRCPAD_STATE_BURST].
+      next_state[CIRCPAD_EVENT_BINS_EMPTY] = CIRCPAD_STATE_END;
+
+  /* No token removal.. end via state_length only */
   ret->states[CIRCPAD_STATE_BURST].token_removal =
       CIRCPAD_TOKEN_REMOVAL_NONE;
 
+  /* Let's have this one end after 12 packets */
+  ret->states[CIRCPAD_STATE_BURST].length_dist.type = CIRCPAD_DIST_UNIFORM;
+  ret->states[CIRCPAD_STATE_BURST].length_dist.param1 = 12;
+  ret->states[CIRCPAD_STATE_BURST].length_dist.param2 = 13;
+  ret->states[CIRCPAD_STATE_BURST].max_length = 12;
+
+  ret->states[CIRCPAD_STATE_BURST].histogram_len = 4;
+
+  ret->states[CIRCPAD_STATE_BURST].histogram_edges[0] = 0;
+  ret->states[CIRCPAD_STATE_BURST].histogram_edges[1] = 1;
+  ret->states[CIRCPAD_STATE_BURST].histogram_edges[2] = 1000000;
+  ret->states[CIRCPAD_STATE_BURST].histogram_edges[3] = 10000000;
+
+  ret->states[CIRCPAD_STATE_BURST].histogram[0] = 0;
+  ret->states[CIRCPAD_STATE_BURST].histogram[1] = 0;
+  ret->states[CIRCPAD_STATE_BURST].histogram[2] = 6;
+
+  ret->states[CIRCPAD_STATE_BURST].histogram_total_tokens = 6;
+  ret->states[CIRCPAD_STATE_BURST].use_rtt_estimate = 0;
+  ret->states[CIRCPAD_STATE_BURST].length_includes_nonpadding = 0;
+
+  return ret;
+}
+
+static circpad_machine_spec_t *
+helper_create_conditional_machine(void)
+{
+  circpad_machine_spec_t *ret =
+    tor_malloc_zero(sizeof(circpad_machine_spec_t));
+
+  /* Start, burst */
+  circpad_machine_states_init(ret, 2);
+
+  ret->states[CIRCPAD_STATE_START].
+      next_state[CIRCPAD_EVENT_PADDING_SENT] = CIRCPAD_STATE_BURST;
+
+  ret->states[CIRCPAD_STATE_BURST].
+      next_state[CIRCPAD_EVENT_PADDING_SENT] = CIRCPAD_STATE_BURST;
+
+  ret->states[CIRCPAD_STATE_BURST].
+      next_state[CIRCPAD_EVENT_LENGTH_COUNT] = CIRCPAD_STATE_END;
+
+  /* Use EXACT removal strategy, otherwise setup_tokens() does not work */
+  ret->states[CIRCPAD_STATE_BURST].token_removal =
+      CIRCPAD_TOKEN_REMOVAL_EXACT;
+
   ret->states[CIRCPAD_STATE_BURST].histogram_len = 3;
-  ret->states[CIRCPAD_STATE_BURST].start_usec = 0;
-  ret->states[CIRCPAD_STATE_BURST].range_usec = 1000000;
+
+  ret->states[CIRCPAD_STATE_BURST].histogram_edges[0] = 0;
+  ret->states[CIRCPAD_STATE_BURST].histogram_edges[1] = 1;
+  ret->states[CIRCPAD_STATE_BURST].histogram_edges[2] = 1000000;
+
   ret->states[CIRCPAD_STATE_BURST].histogram[0] = 6;
   ret->states[CIRCPAD_STATE_BURST].histogram[1] = 0;
-  ret->states[CIRCPAD_STATE_BURST].histogram[1] = 0;
+  ret->states[CIRCPAD_STATE_BURST].histogram[2] = 0;
+
   ret->states[CIRCPAD_STATE_BURST].histogram_total_tokens = 6;
   ret->states[CIRCPAD_STATE_BURST].use_rtt_estimate = 0;
   ret->states[CIRCPAD_STATE_BURST].length_includes_nonpadding = 1;
@@ -1649,8 +1769,11 @@ static void
 helper_create_conditional_machines(void)
 {
   circpad_machine_spec_t *add = helper_create_conditional_machine();
-  origin_padding_machines = smartlist_new();
-  relay_padding_machines = smartlist_new();
+
+  if (!origin_padding_machines)
+    origin_padding_machines = smartlist_new();
+  if (!relay_padding_machines)
+    relay_padding_machines = smartlist_new();
 
   add->machine_num = 2;
   add->is_origin_side = 1;
@@ -1668,8 +1791,7 @@ helper_create_conditional_machines(void)
   add->conditions.state_mask = CIRCPAD_CIRC_BUILDING|
            CIRCPAD_CIRC_NO_STREAMS|CIRCPAD_CIRC_HAS_RELAY_EARLY;
   add->conditions.purpose_mask = CIRCPAD_PURPOSE_ALL;
-
-  smartlist_add(origin_padding_machines, add);
+  circpad_register_padding_machine(add, origin_padding_machines);
 
   add = helper_create_conditional_machine();
   add->machine_num = 3;
@@ -1688,15 +1810,144 @@ helper_create_conditional_machines(void)
   add->conditions.state_mask = CIRCPAD_CIRC_OPENED|
            CIRCPAD_CIRC_STREAMS|CIRCPAD_CIRC_HAS_NO_RELAY_EARLY;
   add->conditions.purpose_mask = CIRCPAD_PURPOSE_ALL;
-  smartlist_add(origin_padding_machines, add);
+  circpad_register_padding_machine(add, origin_padding_machines);
 
   add = helper_create_conditional_machine();
   add->machine_num = 2;
-  smartlist_add(relay_padding_machines, add);
+  circpad_register_padding_machine(add, relay_padding_machines);
 
   add = helper_create_conditional_machine();
   add->machine_num = 3;
-  smartlist_add(relay_padding_machines, add);
+  circpad_register_padding_machine(add, relay_padding_machines);
+}
+
+void
+test_circuitpadding_state_length(void *arg)
+{
+  /**
+   * Test plan:
+   *  * Explicitly test that with no token removal enabled, we hit
+   *    the state length limit due to either padding, or non-padding.
+   *  * Repeat test with an arbitrary token removal strategy, and
+   *    verify that if we run out of tokens due to padding before we
+   *    hit the state length, we still go to state end (all our
+   *    token removal tests only test nonpadding token removal).
+   */
+  int64_t actual_mocked_monotime_start;
+  (void)arg;
+  MOCK(circuitmux_attach_circuit, circuitmux_attach_circuit_mock);
+  MOCK(circpad_send_command_to_hop, circpad_send_command_to_hop_mock);
+
+  nodes_init();
+  dummy_channel.cmux = circuitmux_alloc();
+  relay_side = TO_CIRCUIT(new_fake_orcirc(&dummy_channel,
+                                            &dummy_channel));
+  client_side = TO_CIRCUIT(origin_circuit_new());
+  relay_side->purpose = CIRCUIT_PURPOSE_OR;
+  client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
+
+  monotime_init();
+  monotime_enable_test_mocking();
+  actual_mocked_monotime_start = MONOTIME_MOCK_START;
+  monotime_set_mock_time_nsec(actual_mocked_monotime_start);
+  monotime_coarse_set_mock_time_nsec(actual_mocked_monotime_start);
+  curr_mocked_time = actual_mocked_monotime_start;
+
+  /* This is needed so that we are not considered to be dormant */
+  note_user_activity(20);
+
+  timers_initialize();
+  circpad_machine_spec_t *client_machine =
+      helper_create_length_machine();
+
+  MOCK(circuit_package_relay_cell,
+       circuit_package_relay_cell_mock);
+  MOCK(node_get_by_id,
+       node_get_by_id_mock);
+
+  client_side->padding_machine[0] = client_machine;
+  client_side->padding_info[0] =
+    circpad_circuit_machineinfo_new(client_side, 0);
+  circpad_machine_runtime_t *mi = client_side->padding_info[0];
+
+  circpad_cell_event_padding_sent(client_side);
+  tt_i64_op(mi->state_length, OP_EQ, 12);
+  tt_ptr_op(mi->histogram, OP_EQ, NULL);
+
+  /* Verify that non-padding does not change our state length */
+  circpad_cell_event_nonpadding_sent(client_side);
+  tt_i64_op(mi->state_length, OP_EQ, 12);
+
+  /* verify that sending padding changes our state length */
+  for (uint64_t i = mi->state_length-1; i > 0; i--) {
+    circpad_send_padding_cell_for_callback(mi);
+    tt_i64_op(mi->state_length, OP_EQ, i);
+  }
+  circpad_send_padding_cell_for_callback(mi);
+
+  tt_i64_op(mi->state_length, OP_EQ, -1);
+  tt_int_op(mi->current_state, OP_EQ, CIRCPAD_STATE_END);
+
+  /* Restart machine */
+  mi->current_state = CIRCPAD_STATE_START;
+
+  /* Now, count nonpadding as part of the state length */
+  client_machine->states[CIRCPAD_STATE_BURST].length_includes_nonpadding = 1;
+
+  circpad_cell_event_padding_sent(client_side);
+  tt_i64_op(mi->state_length, OP_EQ, 12);
+
+  /* Verify that non-padding does change our state length now */
+  for (uint64_t i = mi->state_length-1; i > 0; i--) {
+    circpad_cell_event_nonpadding_sent(client_side);
+    tt_i64_op(mi->state_length, OP_EQ, i);
+  }
+
+  circpad_cell_event_nonpadding_sent(client_side);
+  tt_i64_op(mi->state_length, OP_EQ, -1);
+  tt_int_op(mi->current_state, OP_EQ, CIRCPAD_STATE_END);
+
+  /* Now, just test token removal when we send padding */
+  client_machine->states[CIRCPAD_STATE_BURST].token_removal =
+      CIRCPAD_TOKEN_REMOVAL_EXACT;
+
+  /* Restart machine */
+  mi->current_state = CIRCPAD_STATE_START;
+  circpad_cell_event_padding_sent(client_side);
+  tt_i64_op(mi->state_length, OP_EQ, 12);
+  tt_ptr_op(mi->histogram, OP_NE, NULL);
+  tt_int_op(mi->chosen_bin, OP_EQ, 2);
+
+  /* verify that sending padding changes our state length and
+   * our histogram now */
+  for (uint32_t i = mi->histogram[2]-1; i > 0; i--) {
+    circpad_send_padding_cell_for_callback(mi);
+    tt_int_op(mi->chosen_bin, OP_EQ, 2);
+    tt_int_op(mi->histogram[2], OP_EQ, i);
+  }
+
+  tt_i64_op(mi->state_length, OP_EQ, 7);
+  tt_int_op(mi->histogram[2], OP_EQ, 1);
+
+  circpad_send_padding_cell_for_callback(mi);
+  tt_int_op(mi->current_state, OP_EQ, CIRCPAD_STATE_END);
+
+ done:
+  tor_free(client_machine->states);
+  tor_free(client_machine);
+
+  free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
+  free_fake_orcirc(relay_side);
+
+  circuitmux_detach_all_circuits(dummy_channel.cmux, NULL);
+  circuitmux_free(dummy_channel.cmux);
+  timers_shutdown();
+  monotime_disable_test_mocking();
+  UNMOCK(circuit_package_relay_cell);
+  UNMOCK(circuitmux_attach_circuit);
+  UNMOCK(node_get_by_id);
+
+  return;
 }
 
 void
@@ -1720,12 +1971,13 @@ test_circuitpadding_conditions(void *arg)
   int64_t actual_mocked_monotime_start;
   (void)arg;
   MOCK(circuitmux_attach_circuit, circuitmux_attach_circuit_mock);
+  testing_enable_reproducible_rng();
 
   nodes_init();
   dummy_channel.cmux = circuitmux_alloc();
-  relay_side = (circuit_t *)new_fake_orcirc(&dummy_channel,
-                                            &dummy_channel);
-  client_side = (circuit_t *)origin_circuit_new();
+  relay_side = TO_CIRCUIT(new_fake_orcirc(&dummy_channel,
+                                            &dummy_channel));
+  client_side = TO_CIRCUIT(origin_circuit_new());
   relay_side->purpose = CIRCUIT_PURPOSE_OR;
   client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
 
@@ -1736,6 +1988,9 @@ test_circuitpadding_conditions(void *arg)
   monotime_coarse_set_mock_time_nsec(actual_mocked_monotime_start);
   curr_mocked_time = actual_mocked_monotime_start;
 
+  /* This is needed so that we are not considered to be dormant */
+  note_user_activity(20);
+
   timers_initialize();
   helper_create_conditional_machines();
 
@@ -1821,91 +2076,346 @@ test_circuitpadding_conditions(void *arg)
 
  done:
   /* XXX: Free everything */
+  testing_disable_reproducible_rng();
   return;
 }
 
-/** Helper function: Initializes a padding machine where every state uses the
- *  uniform probability distribution.  */
-static void
-helper_circpad_circ_distribution_machine_setup(int min, int max)
+/** Disabled unstable test until #29298 is implemented (see #29122) */
+#if 0
+void
+test_circuitpadding_circuitsetup_machine(void *arg)
 {
-  circpad_machine_states_init(&circ_client_machine, 7);
+  int64_t actual_mocked_monotime_start;
+  /**
+   * Test case plan:
+   *
+   * 1. Simulate a normal circuit setup pattern
+   *    a. Application traffic
+   *
+   * FIXME: This should focus more on exercising the machine
+   * features rather than actual traffic patterns. For example,
+   * test cancellation and bins empty/refill
+   */
+  (void)arg;
 
-  circpad_state_t *zero_st = &circ_client_machine.states[0];
-  zero_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 1;
-  zero_st->iat_dist.type = CIRCPAD_DIST_UNIFORM;
-  zero_st->iat_dist.param1 = min;
-  zero_st->iat_dist.param2 = max;
-  zero_st->start_usec = min;
-  zero_st->range_usec = max;
+  MOCK(circuitmux_attach_circuit, circuitmux_attach_circuit_mock);
 
-  circpad_state_t *first_st = &circ_client_machine.states[1];
-  first_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 2;
-  first_st->iat_dist.type = CIRCPAD_DIST_LOGISTIC;
-  first_st->iat_dist.param1 = min;
-  first_st->iat_dist.param2 = max;
-  first_st->start_usec = min;
-  first_st->range_usec = max;
+  dummy_channel.cmux = circuitmux_alloc();
+  client_side = TO_CIRCUIT(origin_circuit_new());
+  relay_side = TO_CIRCUIT(new_fake_orcirc(&dummy_channel, &dummy_channel));
 
-  circpad_state_t *second_st = &circ_client_machine.states[2];
-  second_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 3;
-  second_st->iat_dist.type = CIRCPAD_DIST_LOG_LOGISTIC;
-  second_st->iat_dist.param1 = min;
-  second_st->iat_dist.param2 = max;
-  second_st->start_usec = min;
-  second_st->range_usec = max;
+  relay_side->purpose = CIRCUIT_PURPOSE_OR;
+  client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
 
-  circpad_state_t *third_st = &circ_client_machine.states[3];
-  third_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 4;
-  third_st->iat_dist.type = CIRCPAD_DIST_GEOMETRIC;
-  third_st->iat_dist.param1 = min;
-  third_st->iat_dist.param2 = max;
-  third_st->start_usec = min;
-  third_st->range_usec = max;
+  nodes_init();
 
-  circpad_state_t *fourth_st = &circ_client_machine.states[4];
-  fourth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 5;
-  fourth_st->iat_dist.type = CIRCPAD_DIST_WEIBULL;
-  fourth_st->iat_dist.param1 = min;
-  fourth_st->iat_dist.param2 = max;
-  fourth_st->start_usec = min;
-  fourth_st->range_usec = max;
+  monotime_init();
+  monotime_enable_test_mocking();
+  actual_mocked_monotime_start = MONOTIME_MOCK_START;
+  monotime_set_mock_time_nsec(actual_mocked_monotime_start);
+  monotime_coarse_set_mock_time_nsec(actual_mocked_monotime_start);
+  curr_mocked_time = actual_mocked_monotime_start;
 
-  circpad_state_t *fifth_st = &circ_client_machine.states[5];
-  fifth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 6;
-  fifth_st->iat_dist.type = CIRCPAD_DIST_PARETO;
-  fifth_st->iat_dist.param1 = min;
-  fifth_st->iat_dist.param2 = max;
-  fifth_st->start_usec = min;
-  fifth_st->range_usec = max;
-}
+  timers_initialize();
+  circpad_machines_init();
 
-/** Simple test that the padding delays sampled from a uniform distribution
- *  actually faill within the uniform distribution range. */
-/* TODO: Upgrade this test so that each state tests a different prob
- * distribution */
-static void
-test_circuitpadding_sample_distribution(void *arg)
-{
-  circpad_machine_state_t *mi;
-  int n_samples;
-  int n_states;
+  MOCK(circuit_package_relay_cell,
+       circuit_package_relay_cell_mock);
+  MOCK(node_get_by_id,
+       node_get_by_id_mock);
 
-  (void) arg;
+  /* Test case #1: Build a 3 hop circuit, then wait and let pad */
+  simulate_single_hop_extend(client_side, relay_side, 1);
+  simulate_single_hop_extend(client_side, relay_side, 1);
+  simulate_single_hop_extend(client_side, relay_side, 1);
 
-  /* mock this function so that we dont actually schedule any padding */
-  MOCK(circpad_machine_schedule_padding,
-       circpad_machine_schedule_padding_mock);
+  tt_int_op(n_client_cells, OP_EQ, 1);
+  tt_int_op(n_relay_cells, OP_EQ, 1);
+  tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
+                CIRCPAD_STATE_BURST);
+  tt_int_op(relay_side->padding_info[0]->current_state, OP_EQ,
+          CIRCPAD_STATE_BURST);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  tt_int_op(relay_side->padding_info[0]->is_padding_timer_scheduled,
+            OP_EQ, 0);
+  timers_advance_and_run(2000);
+  tt_int_op(n_client_cells, OP_EQ, 2);
+  tt_int_op(n_relay_cells, OP_EQ, 1);
 
-  /* Initialize a machine with multiple probability distributions that should
-   * return values between 0 and 5 */
-  circpad_machines_init();
-  helper_circpad_circ_distribution_machine_setup(0, 10);
+  tt_int_op(relay_side->padding_info[0]->current_state, OP_EQ,
+              CIRCPAD_STATE_GAP);
 
-  /* Initialize machine and circuits */
-  client_side = TO_CIRCUIT(origin_circuit_new());
-  client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
-  client_side->padding_machine[0] = &circ_client_machine;
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  timers_advance_and_run(5000);
+  tt_int_op(n_client_cells, OP_EQ, 2);
+  tt_int_op(n_relay_cells, OP_EQ, 2);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  timers_advance_and_run(2000);
+  tt_int_op(n_client_cells, OP_EQ, 3);
+  tt_int_op(n_relay_cells, OP_EQ, 2);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  timers_advance_and_run(5000);
+  tt_int_op(n_client_cells, OP_EQ, 3);
+  tt_int_op(n_relay_cells, OP_EQ, 3);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  timers_advance_and_run(2000);
+  tt_int_op(n_client_cells, OP_EQ, 4);
+  tt_int_op(n_relay_cells, OP_EQ, 3);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  timers_advance_and_run(5000);
+  tt_int_op(n_client_cells, OP_EQ, 4);
+  tt_int_op(n_relay_cells, OP_EQ, 4);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  timers_advance_and_run(2000);
+  tt_int_op(n_client_cells, OP_EQ, 5);
+  tt_int_op(n_relay_cells, OP_EQ, 4);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  timers_advance_and_run(5000);
+  tt_int_op(n_client_cells, OP_EQ, 5);
+  tt_int_op(n_relay_cells, OP_EQ, 5);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  timers_advance_and_run(2000);
+  tt_int_op(n_client_cells, OP_EQ, 6);
+  tt_int_op(n_relay_cells, OP_EQ, 5);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  timers_advance_and_run(5000);
+  tt_int_op(n_client_cells, OP_EQ, 6);
+  tt_int_op(n_relay_cells, OP_EQ, 6);
+
+  tt_int_op(client_side->padding_info[0]->current_state,
+            OP_EQ, CIRCPAD_STATE_END);
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  tt_int_op(relay_side->padding_info[0]->current_state,
+            OP_EQ, CIRCPAD_STATE_GAP);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+
+  /* Verify we can't schedule padding in END state */
+  circpad_decision_t ret =
+      circpad_machine_schedule_padding(client_side->padding_info[0]);
+  tt_int_op(ret, OP_EQ, CIRCPAD_STATE_UNCHANGED);
+
+  /* Simulate application traffic */
+  circpad_cell_event_nonpadding_sent(client_side);
+  circpad_deliver_unrecognized_cell_events(relay_side, CELL_DIRECTION_OUT);
+  circpad_deliver_unrecognized_cell_events(relay_side, CELL_DIRECTION_IN);
+  circpad_deliver_recognized_relay_cell_events(client_side, RELAY_COMMAND_DATA,
+                                  TO_ORIGIN_CIRCUIT(client_side)->cpath->next);
+
+  tt_ptr_op(client_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(client_side->padding_machine[0], OP_EQ, NULL);
+
+  tt_ptr_op(relay_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(relay_side->padding_machine[0], OP_EQ, NULL);
+  tt_int_op(n_client_cells, OP_EQ, 6);
+  tt_int_op(n_relay_cells, OP_EQ, 7);
+
+  // Test timer cancellation
+  simulate_single_hop_extend(client_side, relay_side, 1);
+  simulate_single_hop_extend(client_side, relay_side, 1);
+  timers_advance_and_run(5000);
+  circpad_cell_event_padding_received(client_side);
+
+  tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
+                CIRCPAD_STATE_BURST);
+  tt_int_op(relay_side->padding_info[0]->current_state, OP_EQ,
+          CIRCPAD_STATE_GAP);
+
+  tt_int_op(n_client_cells, OP_EQ, 8);
+  tt_int_op(n_relay_cells, OP_EQ, 8);
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+
+  /* Test timer cancel due to state rules */
+  circpad_cell_event_nonpadding_sent(client_side);
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_EQ, 0);
+  circpad_cell_event_padding_received(client_side);
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+
+  /* Simulate application traffic to cancel timer */
+  circpad_cell_event_nonpadding_sent(client_side);
+  circpad_deliver_unrecognized_cell_events(relay_side, CELL_DIRECTION_OUT);
+  circpad_deliver_unrecognized_cell_events(relay_side, CELL_DIRECTION_IN);
+  circpad_deliver_recognized_relay_cell_events(client_side, RELAY_COMMAND_DATA,
+                                  TO_ORIGIN_CIRCUIT(client_side)->cpath->next);
+
+  tt_ptr_op(client_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(client_side->padding_machine[0], OP_EQ, NULL);
+
+  tt_ptr_op(relay_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(relay_side->padding_machine[0], OP_EQ, NULL);
+
+  /* No cells sent, except negotiate end from relay */
+  tt_int_op(n_client_cells, OP_EQ, 8);
+  tt_int_op(n_relay_cells, OP_EQ, 9);
+
+  /* Test mark for close and free */
+  simulate_single_hop_extend(client_side, relay_side, 1);
+  simulate_single_hop_extend(client_side, relay_side, 1);
+  timers_advance_and_run(5000);
+  circpad_cell_event_padding_received(client_side);
+
+  tt_int_op(n_client_cells, OP_EQ, 10);
+  tt_int_op(n_relay_cells, OP_EQ, 10);
+
+  tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
+                CIRCPAD_STATE_BURST);
+  tt_int_op(relay_side->padding_info[0]->current_state, OP_EQ,
+          CIRCPAD_STATE_GAP);
+
+  tt_u64_op(client_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  tt_u64_op(relay_side->padding_info[0]->padding_scheduled_at_usec,
+            OP_NE, 0);
+  circuit_mark_for_close(client_side, END_CIRC_REASON_FLAG_REMOTE);
+  free_fake_orcirc(relay_side);
+  timers_advance_and_run(5000);
+
+  /* No cells sent */
+  tt_int_op(n_client_cells, OP_EQ, 10);
+  tt_int_op(n_relay_cells, OP_EQ, 10);
+
+ done:
+  free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
+
+  circuitmux_detach_all_circuits(dummy_channel.cmux, NULL);
+  circuitmux_free(dummy_channel.cmux);
+  timers_shutdown();
+  monotime_disable_test_mocking();
+  UNMOCK(circuit_package_relay_cell);
+  UNMOCK(circuitmux_attach_circuit);
+
+  return;
+}
+#endif /* 0 */
+
+/** Helper function: Initializes a padding machine where every state uses the
+ *  uniform probability distribution.  */
+static void
+helper_circpad_circ_distribution_machine_setup(int min, int max)
+{
+  circpad_machine_states_init(&circ_client_machine, 7);
+
+  circpad_state_t *zero_st = &circ_client_machine.states[0];
+  zero_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 1;
+  zero_st->iat_dist.type = CIRCPAD_DIST_UNIFORM;
+  /* param2 is upper bound, param1 is lower */
+  zero_st->iat_dist.param1 = min;
+  zero_st->iat_dist.param2 = max;
+  zero_st->dist_added_shift_usec = min;
+  zero_st->dist_max_sample_usec = max;
+
+  circpad_state_t *first_st = &circ_client_machine.states[1];
+  first_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 2;
+  first_st->iat_dist.type = CIRCPAD_DIST_LOGISTIC;
+  /* param1 is Mu, param2 is sigma. */
+  first_st->iat_dist.param1 = 9;
+  first_st->iat_dist.param2 = 3;
+  first_st->dist_added_shift_usec = min;
+  first_st->dist_max_sample_usec = max;
+
+  circpad_state_t *second_st = &circ_client_machine.states[2];
+  second_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 3;
+  second_st->iat_dist.type = CIRCPAD_DIST_LOG_LOGISTIC;
+  /* param1 is Alpha, param2 is 1.0/Beta */
+  second_st->iat_dist.param1 = 1;
+  second_st->iat_dist.param2 = 0.5;
+  second_st->dist_added_shift_usec = min;
+  second_st->dist_max_sample_usec = max;
+
+  circpad_state_t *third_st = &circ_client_machine.states[3];
+  third_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 4;
+  third_st->iat_dist.type = CIRCPAD_DIST_GEOMETRIC;
+  /* param1 is 'p' (success probability) */
+  third_st->iat_dist.param1 = 0.2;
+  third_st->dist_added_shift_usec = min;
+  third_st->dist_max_sample_usec = max;
+
+  circpad_state_t *fourth_st = &circ_client_machine.states[4];
+  fourth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 5;
+  fourth_st->iat_dist.type = CIRCPAD_DIST_WEIBULL;
+  /* param1 is k, param2 is Lambda */
+  fourth_st->iat_dist.param1 = 1.5;
+  fourth_st->iat_dist.param2 = 1;
+  fourth_st->dist_added_shift_usec = min;
+  fourth_st->dist_max_sample_usec = max;
+
+  circpad_state_t *fifth_st = &circ_client_machine.states[5];
+  fifth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 6;
+  fifth_st->iat_dist.type = CIRCPAD_DIST_PARETO;
+  /* param1 is sigma, param2 is xi */
+  fifth_st->iat_dist.param1 = 1;
+  fifth_st->iat_dist.param2 = 5;
+  fifth_st->dist_added_shift_usec = min;
+  fifth_st->dist_max_sample_usec = max;
+}
+
+/** Simple test that the padding delays sampled from a uniform distribution
+ *  actually faill within the uniform distribution range. */
+static void
+test_circuitpadding_sample_distribution(void *arg)
+{
+  circpad_machine_runtime_t *mi;
+  int n_samples;
+  int n_states;
+
+  (void) arg;
+
+  /* mock this function so that we dont actually schedule any padding */
+  MOCK(circpad_machine_schedule_padding,
+       circpad_machine_schedule_padding_mock);
+  testing_enable_reproducible_rng();
+
+  /* Initialize a machine with multiple probability distributions */
+  circpad_machines_init();
+  helper_circpad_circ_distribution_machine_setup(0, 10);
+
+  /* Initialize machine and circuits */
+  client_side = TO_CIRCUIT(origin_circuit_new());
+  client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
+  client_side->padding_machine[0] = &circ_client_machine;
   client_side->padding_info[0] =
     circpad_circuit_machineinfo_new(client_side, 0);
   mi = client_side->padding_info[0];
@@ -1923,16 +2433,17 @@ test_circuitpadding_sample_distribution(void *arg)
     }
 
     /* send a non-padding cell to move to the next machine state */
-    circpad_cell_event_nonpadding_received((circuit_t*)client_side);
+    circpad_cell_event_nonpadding_received(client_side);
   }
 
  done:
   free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
   UNMOCK(circpad_machine_schedule_padding);
+  testing_disable_reproducible_rng();
 }
 
 static circpad_decision_t
-circpad_machine_spec_transition_mock(circpad_machine_state_t *mi,
+circpad_machine_spec_transition_mock(circpad_machine_runtime_t *mi,
                                 circpad_event_t event)
 {
   (void) mi;
@@ -1947,13 +2458,14 @@ test_circuitpadding_machine_rate_limiting(void *arg)
 {
   (void) arg;
   bool retval;
-  circpad_machine_state_t *mi;
+  circpad_machine_runtime_t *mi;
   int i;
 
   /* Ignore machine transitions for the purposes of this function, we only
    * really care about padding counts */
   MOCK(circpad_machine_spec_transition, circpad_machine_spec_transition_mock);
   MOCK(circpad_send_command_to_hop, circpad_send_command_to_hop_mock);
+  testing_enable_reproducible_rng();
 
   /* Setup machine and circuits */
   client_side = TO_CIRCUIT(origin_circuit_new());
@@ -2007,6 +2519,7 @@ test_circuitpadding_machine_rate_limiting(void *arg)
 
  done:
   free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
+  testing_disable_reproducible_rng();
 }
 
 /* Test global padding rate limits */
@@ -2015,7 +2528,7 @@ test_circuitpadding_global_rate_limiting(void *arg)
 {
   (void) arg;
   bool retval;
-  circpad_machine_state_t *mi;
+  circpad_machine_runtime_t *mi;
   int i;
   int64_t actual_mocked_monotime_start;
 
@@ -2026,6 +2539,7 @@ test_circuitpadding_global_rate_limiting(void *arg)
   MOCK(circuit_package_relay_cell,
        circuit_package_relay_cell_mock);
   MOCK(monotime_absolute_usec, mock_monotime_absolute_usec);
+  testing_enable_reproducible_rng();
 
   monotime_init();
   monotime_enable_test_mocking();
@@ -2035,12 +2549,12 @@ test_circuitpadding_global_rate_limiting(void *arg)
   curr_mocked_time = actual_mocked_monotime_start;
   timers_initialize();
 
-  client_side = (circuit_t *)origin_circuit_new();
+  client_side = TO_CIRCUIT(origin_circuit_new());
   client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
   dummy_channel.cmux = circuitmux_alloc();
 
   /* Setup machine and circuits */
-  relay_side = (circuit_t *)new_fake_orcirc(&dummy_channel, &dummy_channel);
+  relay_side = TO_CIRCUIT(new_fake_orcirc(&dummy_channel, &dummy_channel));
   relay_side->purpose = CIRCUIT_PURPOSE_OR;
   helper_create_basic_machine();
   relay_side->padding_machine[0] = &circ_client_machine;
@@ -2105,6 +2619,537 @@ test_circuitpadding_global_rate_limiting(void *arg)
   circuitmux_free(dummy_channel.cmux);
   SMARTLIST_FOREACH(vote1.net_params, char *, cp, tor_free(cp));
   smartlist_free(vote1.net_params);
+  testing_disable_reproducible_rng();
+}
+
+/* Test reduced and disabled padding */
+static void
+test_circuitpadding_reduce_disable(void *arg)
+{
+  (void) arg;
+  int64_t actual_mocked_monotime_start;
+
+  MOCK(circuitmux_attach_circuit, circuitmux_attach_circuit_mock);
+  testing_enable_reproducible_rng();
+
+  nodes_init();
+  dummy_channel.cmux = circuitmux_alloc();
+  relay_side = (circuit_t *)new_fake_orcirc(&dummy_channel,
+                                            &dummy_channel);
+  client_side = (circuit_t *)origin_circuit_new();
+  relay_side->purpose = CIRCUIT_PURPOSE_OR;
+  client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
+
+  circpad_machines_init();
+  helper_create_conditional_machines();
+
+  monotime_init();
+  monotime_enable_test_mocking();
+  actual_mocked_monotime_start = MONOTIME_MOCK_START;
+  monotime_set_mock_time_nsec(actual_mocked_monotime_start);
+  monotime_coarse_set_mock_time_nsec(actual_mocked_monotime_start);
+  curr_mocked_time = actual_mocked_monotime_start;
+  timers_initialize();
+
+  /* This is needed so that we are not considered to be dormant */
+  note_user_activity(20);
+
+  MOCK(circuit_package_relay_cell,
+       circuit_package_relay_cell_mock);
+  MOCK(node_get_by_id,
+       node_get_by_id_mock);
+
+  /* Simulate extend. This should result in the original machine getting
+   * added, since the circuit is not built */
+  simulate_single_hop_extend(client_side, relay_side, 1);
+  simulate_single_hop_extend(client_side, relay_side, 1);
+
+  /* Verify that machine #2 is added */
+  tt_int_op(client_side->padding_machine[0]->machine_num, OP_EQ, 2);
+  tt_int_op(relay_side->padding_machine[0]->machine_num, OP_EQ, 2);
+
+  /* Deliver a padding cell to the client, to trigger burst state */
+  circpad_cell_event_padding_sent(client_side);
+
+  /* This should have trigger length shutdown condition on client.. */
+  tt_ptr_op(client_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(client_side->padding_machine[0], OP_EQ, NULL);
+
+  /* Verify machine is gone from both sides */
+  tt_ptr_op(relay_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(relay_side->padding_machine[0], OP_EQ, NULL);
+
+  /* Now test the reduced padding machine by setting up the consensus */
+  networkstatus_t vote1;
+  vote1.net_params = smartlist_new();
+  smartlist_split_string(vote1.net_params,
+         "circpad_padding_reduced=1", NULL, 0, 0);
+
+  /* Register reduced padding machine with the padding subsystem */
+  circpad_new_consensus_params(&vote1);
+
+  simulate_single_hop_extend(client_side, relay_side, 1);
+
+  /* Verify that machine #0 is added */
+  tt_int_op(client_side->padding_machine[0]->machine_num, OP_EQ, 2);
+  tt_int_op(relay_side->padding_machine[0]->machine_num, OP_EQ, 2);
+
+  tt_int_op(
+    circpad_machine_reached_padding_limit(client_side->padding_info[0]),
+    OP_EQ, 0);
+  tt_int_op(
+    circpad_machine_reached_padding_limit(relay_side->padding_info[0]),
+    OP_EQ, 0);
+
+  /* Test that machines get torn down when padding is disabled */
+  SMARTLIST_FOREACH(vote1.net_params, char *, cp, tor_free(cp));
+  smartlist_free(vote1.net_params);
+  vote1.net_params = smartlist_new();
+  smartlist_split_string(vote1.net_params,
+         "circpad_padding_disabled=1", NULL, 0, 0);
+
+  /* Register reduced padding machine with the padding subsystem */
+  circpad_new_consensus_params(&vote1);
+
+  tt_int_op(
+    circpad_machine_schedule_padding(client_side->padding_info[0]),
+    OP_EQ, CIRCPAD_STATE_UNCHANGED);
+  tt_int_op(
+    circpad_machine_schedule_padding(relay_side->padding_info[0]),
+    OP_EQ, CIRCPAD_STATE_UNCHANGED);
+
+  /* Signal that circuit is built: this event causes us to re-evaluate
+   * machine conditions (which don't apply because padding is disabled). */
+  circpad_machine_event_circ_built(TO_ORIGIN_CIRCUIT(client_side));
+
+  tt_ptr_op(client_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(client_side->padding_machine[0], OP_EQ, NULL);
+  tt_ptr_op(relay_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(relay_side->padding_machine[0], OP_EQ, NULL);
+
+  SMARTLIST_FOREACH(vote1.net_params, char *, cp, tor_free(cp));
+  smartlist_free(vote1.net_params);
+  vote1.net_params = NULL;
+  circpad_new_consensus_params(&vote1);
+
+  get_options_mutable()->ReducedCircuitPadding = 1;
+
+  simulate_single_hop_extend(client_side, relay_side, 1);
+
+  /* Verify that machine #0 is added */
+  tt_int_op(client_side->padding_machine[0]->machine_num, OP_EQ, 2);
+  tt_int_op(relay_side->padding_machine[0]->machine_num, OP_EQ, 2);
+
+  tt_int_op(
+    circpad_machine_reached_padding_limit(client_side->padding_info[0]),
+    OP_EQ, 0);
+  tt_int_op(
+    circpad_machine_reached_padding_limit(relay_side->padding_info[0]),
+    OP_EQ, 0);
+
+  get_options_mutable()->CircuitPadding = 0;
+
+  tt_int_op(
+    circpad_machine_schedule_padding(client_side->padding_info[0]),
+    OP_EQ, CIRCPAD_STATE_UNCHANGED);
+  tt_int_op(
+    circpad_machine_schedule_padding(relay_side->padding_info[0]),
+    OP_EQ, CIRCPAD_STATE_UNCHANGED);
+
+  /* Signal that circuit is built: this event causes us to re-evaluate
+   * machine conditions (which don't apply because padding is disabled). */
+
+  circpad_machine_event_circ_built(TO_ORIGIN_CIRCUIT(client_side));
+
+  tt_ptr_op(client_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(client_side->padding_machine[0], OP_EQ, NULL);
+  tt_ptr_op(relay_side->padding_info[0], OP_EQ, NULL);
+  tt_ptr_op(relay_side->padding_machine[0], OP_EQ, NULL);
+
+ done:
+  free_fake_orcirc(relay_side);
+  circuitmux_detach_all_circuits(dummy_channel.cmux, NULL);
+  circuitmux_free(dummy_channel.cmux);
+  testing_disable_reproducible_rng();
+}
+
+/** Just a basic machine whose whole purpose is to reach the END state */
+static void
+helper_create_ender_machine(void)
+{
+  /* Start, burst */
+  circpad_machine_states_init(&circ_client_machine, 2);
+
+  circ_client_machine.states[CIRCPAD_STATE_START].
+      next_state[CIRCPAD_EVENT_NONPADDING_RECV] = CIRCPAD_STATE_END;
+
+  circ_client_machine.conditions.state_mask = CIRCPAD_STATE_ALL;
+  circ_client_machine.conditions.purpose_mask = CIRCPAD_PURPOSE_ALL;
+}
+
+static time_t mocked_timeofday;
+/** Set timeval to a mock date and time. This is necessary
+ * to make tor_gettimeofday() mockable. */
+static void
+mock_tor_gettimeofday(struct timeval *timeval)
+{
+  timeval->tv_sec = mocked_timeofday;
+  timeval->tv_usec = 0;
+}
+
+/** Test manual managing of circuit lifetimes by the circuitpadding
+ *  subsystem. In particular this test goes through all the cases of the
+ *  circpad_marked_circuit_for_padding() function, via
+ *  circuit_mark_for_close() as well as
+ *  circuit_expire_old_circuits_clientside(). */
+static void
+test_circuitpadding_manage_circuit_lifetime(void *arg)
+{
+  circpad_machine_runtime_t *mi;
+
+  (void) arg;
+
+  client_side = (circuit_t *)origin_circuit_new();
+  client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
+  monotime_enable_test_mocking();
+  MOCK(tor_gettimeofday, mock_tor_gettimeofday);
+  mocked_timeofday = 23;
+
+  helper_create_ender_machine();
+
+  /* Enable manual circuit lifetime manage for this test */
+  circ_client_machine.manage_circ_lifetime = 1;
+
+  /* Test setup */
+  client_side->padding_machine[0] = &circ_client_machine;
+  client_side->padding_info[0] =
+    circpad_circuit_machineinfo_new(client_side, 0);
+  mi = client_side->padding_info[0];
+
+  tt_int_op(mi->current_state, OP_EQ, CIRCPAD_STATE_START);
+
+  /* Check that the circuit is not marked for close */
+  tt_int_op(client_side->marked_for_close, OP_EQ, 0);
+  tt_int_op(client_side->purpose, OP_EQ, CIRCUIT_PURPOSE_C_GENERAL);
+
+  /* Mark this circuit for close due to a remote reason */
+  circuit_mark_for_close(client_side,
+                         END_CIRC_REASON_FLAG_REMOTE|END_CIRC_REASON_NONE);
+  tt_ptr_op(client_side->padding_info[0], OP_NE, NULL);
+  tt_int_op(client_side->marked_for_close, OP_NE, 0);
+  tt_int_op(client_side->purpose, OP_EQ, CIRCUIT_PURPOSE_C_GENERAL);
+  client_side->marked_for_close = 0;
+
+  /* Mark this circuit for close due to a protocol issue */
+  circuit_mark_for_close(client_side, END_CIRC_REASON_TORPROTOCOL);
+  tt_int_op(client_side->marked_for_close, OP_NE, 0);
+  tt_int_op(client_side->purpose, OP_EQ, CIRCUIT_PURPOSE_C_GENERAL);
+  client_side->marked_for_close = 0;
+
+  /* Mark a measurement circuit for close */
+  client_side->purpose = CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT;
+  circuit_mark_for_close(client_side, END_CIRC_REASON_NONE);
+  tt_int_op(client_side->marked_for_close, OP_NE, 0);
+  tt_int_op(client_side->purpose, OP_EQ, CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT);
+  client_side->marked_for_close = 0;
+
+  /* Mark a general circuit for close */
+  client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
+  circuit_mark_for_close(client_side, END_CIRC_REASON_NONE);
+
+  /* Check that this circuit is still not marked for close since we are
+   * managing the lifetime manually, but the circuit was tagged as such by the
+   * circpadding subsystem */
+  tt_int_op(client_side->marked_for_close, OP_EQ, 0);
+  tt_int_op(client_side->purpose, OP_EQ, CIRCUIT_PURPOSE_C_CIRCUIT_PADDING);
+
+  /* We just tested case (1) from the comments of
+   * circpad_circuit_should_be_marked_for_close() */
+
+  /* Transition the machine to the END state but did not delete its machine */
+  tt_ptr_op(client_side->padding_info[0], OP_NE, NULL);
+  circpad_cell_event_nonpadding_received(client_side);
+  tt_int_op(mi->current_state, OP_EQ, CIRCPAD_STATE_END);
+
+  /* We just tested case (3) from the comments of
+   * circpad_circuit_should_be_marked_for_close().
+   * Now let's go for case (2). */
+
+  /* Reset the close mark */
+  client_side->marked_for_close = 0;
+
+  /* Mark this circuit for close */
+  circuit_mark_for_close(client_side, 0);
+
+  /* See that the circ got closed since we are already in END state */
+  tt_int_op(client_side->marked_for_close, OP_NE, 0);
+
+  /* We just tested case (2). Now let's see that case (4) is unreachable as
+     that comment claims */
+
+  /* First, reset all close marks and tags */
+  client_side->marked_for_close = 0;
+  client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
+
+  /* Now re-create the ender machine so that we can transition to END again */
+  /* Free up some stuff first */
+  circpad_circuit_free_all_machineinfos(client_side);
+  tor_free(circ_client_machine.states);
+  helper_create_ender_machine();
+
+  client_side->padding_machine[0] = &circ_client_machine;
+  client_side->padding_info[0] =
+    circpad_circuit_machineinfo_new(client_side, 0);
+  mi = client_side->padding_info[0];
+
+  /* Check we are in START. */
+  tt_int_op(mi->current_state, OP_EQ, CIRCPAD_STATE_START);
+
+  /* Test that we don't expire this circuit yet */
+  client_side->timestamp_dirty = 0;
+  client_side->state = CIRCUIT_STATE_OPEN;
+  tor_gettimeofday(&client_side->timestamp_began);
+  TO_ORIGIN_CIRCUIT(client_side)->circuit_idle_timeout = 23;
+  mocked_timeofday += 24;
+  circuit_expire_old_circuits_clientside();
+  circuit_expire_old_circuits_clientside();
+  circuit_expire_old_circuits_clientside();
+  tt_int_op(client_side->timestamp_dirty, OP_NE, 0);
+  tt_int_op(client_side->marked_for_close, OP_EQ, 0);
+  tt_int_op(client_side->purpose, OP_EQ, CIRCUIT_PURPOSE_C_CIRCUIT_PADDING);
+
+  /* Runaway circpad test: if the machine does not transition to end,
+   * test that after CIRCPAD_DELAY_MAX_SECS, we get marked anyway */
+  mocked_timeofday = client_side->timestamp_dirty
+      + get_options()->MaxCircuitDirtiness + 2;
+  client_side->padding_info[0]->last_cell_time_sec =
+      approx_time()-(CIRCPAD_DELAY_MAX_SECS+10);
+  circuit_expire_old_circuits_clientside();
+  tt_int_op(client_side->marked_for_close, OP_NE, 0);
+
+  /* Test back to normal: if we had activity, we won't close */
+  client_side->padding_info[0]->last_cell_time_sec = approx_time();
+  client_side->marked_for_close = 0;
+  circuit_expire_old_circuits_clientside();
+  tt_int_op(client_side->marked_for_close, OP_EQ, 0);
+
+  /* Transition to END, but before we're past the dirty timer */
+  mocked_timeofday = client_side->timestamp_dirty;
+  circpad_cell_event_nonpadding_received(client_side);
+  tt_int_op(mi->current_state, OP_EQ, CIRCPAD_STATE_END);
+
+  /* Verify that the circuit was not closed. */
+  tt_int_op(client_side->marked_for_close, OP_EQ, 0);
+
+  /* Now that we are in END state, we can be closed by expiry, but via
+   * the timestamp_dirty path, not the idle path. So first test not dirty
+   * enough. */
+  mocked_timeofday = client_side->timestamp_dirty;
+  circuit_expire_old_circuits_clientside();
+  tt_int_op(client_side->marked_for_close, OP_EQ, 0);
+  mocked_timeofday = client_side->timestamp_dirty
+      + get_options()->MaxCircuitDirtiness + 2;
+  circuit_expire_old_circuits_clientside();
+  tt_int_op(client_side->marked_for_close, OP_NE, 0);
+
+ done:
+  free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
+  tor_free(circ_client_machine.states);
+  monotime_disable_test_mocking();
+  UNMOCK(tor_gettimeofday);
+}
+
+/** Helper for the test_circuitpadding_hs_machines test:
+ *
+ *  - Create a client and relay circuit.
+ *  - Setup right circuit purpose and attach a machine to the client circuit.
+ *  - Verify that state transitions work as intended and state length gets
+ *    enforced.
+ *
+ *  This function is able to do this test both for intro and rend circuits
+ *  depending on the value of <b>test_intro_circs</b>.
+ */
+static void
+helper_test_hs_machines(bool test_intro_circs)
+{
+  /* Setup the circuits */
+  origin_circuit_t *origin_client_side = origin_circuit_new();
+  client_side = TO_CIRCUIT(origin_client_side);
+  client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
+
+  dummy_channel.cmux = circuitmux_alloc();
+  relay_side = TO_CIRCUIT(new_fake_orcirc(&dummy_channel, &dummy_channel));
+  relay_side->purpose = CIRCUIT_PURPOSE_OR;
+
+  /* extend the client circ to two hops */
+  simulate_single_hop_extend(client_side, relay_side, 1);
+  simulate_single_hop_extend(client_side, relay_side, 1);
+
+  /* machines only apply on opened circuits */
+  origin_client_side->has_opened = 1;
+
+  /************************************/
+
+  /* Attaching the client machine now won't work here because of a wrong
+   * purpose */
+  tt_assert(!client_side->padding_machine[0]);
+  circpad_add_matching_machines(origin_client_side, origin_padding_machines);
+  tt_assert(!client_side->padding_machine[0]);
+
+  /* Change the purpose, see the machine getting attached */
+  client_side->purpose = test_intro_circs ?
+    CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT : CIRCUIT_PURPOSE_C_REND_JOINED;
+  circpad_add_matching_machines(origin_client_side, origin_padding_machines);
+  tt_ptr_op(client_side->padding_info[0], OP_NE, NULL);
+  tt_ptr_op(client_side->padding_machine[0], OP_NE, NULL);
+
+  tt_ptr_op(relay_side->padding_info[0], OP_NE, NULL);
+  tt_ptr_op(relay_side->padding_machine[0], OP_NE, NULL);
+
+  /* Verify that the right machine is attached */
+  tt_str_op(client_side->padding_machine[0]->name, OP_EQ,
+            test_intro_circs ? "client_ip_circ" : "client_rp_circ");
+  tt_str_op(relay_side->padding_machine[0]->name, OP_EQ,
+            test_intro_circs ? "relay_ip_circ": "relay_rp_circ");
+
+  /***********************************/
+
+  /* Intro machines are at START state, but rend machines have already skipped
+   * to OBFUSCATE_CIRC_SETUP because of the sent PADDING_NEGOTIATE. */
+  tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
+            CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP);
+  tt_int_op(relay_side->padding_info[0]->current_state, OP_EQ,
+            CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP);
+
+  /*Send non-padding to move the machines from START to OBFUSCATE_CIRC_SETUP */
+  circpad_cell_event_nonpadding_received(client_side);
+  circpad_cell_event_nonpadding_received(relay_side);
+  tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
+            CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP);
+  tt_int_op(relay_side->padding_info[0]->current_state, OP_EQ,
+            CIRCPAD_STATE_OBFUSCATE_CIRC_SETUP);
+
+  /* Check that the state lengths have been sampled and are within range */
+  circpad_machine_runtime_t *client_machine_runtime =
+    client_side->padding_info[0];
+  circpad_machine_runtime_t *relay_machine_runtime =
+    relay_side->padding_info[0];
+
+  if (test_intro_circs) {
+    /* on the client side, we don't send any padding so
+     * state length is not set */
+    tt_i64_op(client_machine_runtime->state_length, OP_EQ, -1);
+    /* relay side has state limits. check them */
+    tt_i64_op(relay_machine_runtime->state_length, OP_GE,
+              INTRO_MACHINE_MINIMUM_PADDING);
+    tt_i64_op(relay_machine_runtime->state_length, OP_LT,
+              INTRO_MACHINE_MAXIMUM_PADDING);
+  } else {
+    tt_i64_op(client_machine_runtime->state_length, OP_EQ, 1);
+    tt_i64_op(relay_machine_runtime->state_length, OP_EQ, 1);
+  }
+
+  if (test_intro_circs) {
+    int i;
+    /* Send state_length worth of padding from the relay and see that the
+     * client state goes to END */
+    for (i = (int) relay_machine_runtime->state_length ; i > 0 ; i--) {
+      circpad_send_padding_cell_for_callback(relay_machine_runtime);
+    }
+    /* See that the machine has been teared down after all the length has been
+     * exhausted (the padding info should now be null on both sides) */
+    tt_ptr_op(relay_side->padding_info[0], OP_EQ, NULL);
+    tt_ptr_op(client_side->padding_info[0], OP_EQ, NULL);
+  } else {
+    int i;
+    /* Send state_length worth of padding and see that the state goes to END */
+    for (i = (int) client_machine_runtime->state_length ; i > 0 ; i--) {
+      circpad_send_padding_cell_for_callback(client_machine_runtime);
+    }
+    /* See that the machine has been teared down after all the length has been
+     * exhausted. */
+    tt_int_op(client_side->padding_info[0]->current_state, OP_EQ,
+              CIRCPAD_STATE_END);
+  }
+
+ done:
+  free_fake_orcirc(relay_side);
+  circuitmux_detach_all_circuits(dummy_channel.cmux, NULL);
+  circuitmux_free(dummy_channel.cmux);
+  free_fake_origin_circuit(TO_ORIGIN_CIRCUIT(client_side));
+}
+
+/** Test that the HS circuit padding machines work as intended. */
+static void
+test_circuitpadding_hs_machines(void *arg)
+{
+  (void)arg;
+
+  /* Test logic:
+   *
+   * 1) Register the HS machines, which aim to hide the presense of
+   *    onion service traffic on the client-side
+   *
+   * 2) Call helper_test_hs_machines() to perform tests for the intro circuit
+   *    machines and for the rend circuit machines.
+  */
+
+  MOCK(circuitmux_attach_circuit, circuitmux_attach_circuit_mock);
+  MOCK(circuit_package_relay_cell, circuit_package_relay_cell_mock);
+  MOCK(circuit_get_nth_node, circuit_get_nth_node_mock);
+  MOCK(circpad_machine_schedule_padding,circpad_machine_schedule_padding_mock);
+
+  origin_padding_machines = smartlist_new();
+  relay_padding_machines = smartlist_new();
+
+  nodes_init();
+
+  monotime_init();
+  monotime_enable_test_mocking();
+  monotime_set_mock_time_nsec(1*TOR_NSEC_PER_USEC);
+  monotime_coarse_set_mock_time_nsec(1*TOR_NSEC_PER_USEC);
+  curr_mocked_time = 1*TOR_NSEC_PER_USEC;
+
+  timers_initialize();
+
+  /* This is needed so that we are not considered to be dormant */
+  note_user_activity(20);
+
+  /************************************/
+
+  /* Register the HS machines */
+  circpad_machine_client_hide_intro_circuits(origin_padding_machines);
+  circpad_machine_client_hide_rend_circuits(origin_padding_machines);
+  circpad_machine_relay_hide_intro_circuits(relay_padding_machines);
+  circpad_machine_relay_hide_rend_circuits(relay_padding_machines);
+
+  /***********************************/
+
+  /* Do the tests for the intro circuit machines */
+  helper_test_hs_machines(true);
+  /* Do the tests for the rend circuit machines */
+  helper_test_hs_machines(false);
+
+  timers_shutdown();
+  monotime_disable_test_mocking();
+
+  SMARTLIST_FOREACH_BEGIN(origin_padding_machines,
+                          circpad_machine_spec_t *, m) {
+    machine_spec_free(m);
+  } SMARTLIST_FOREACH_END(m);
+
+  SMARTLIST_FOREACH_BEGIN(relay_padding_machines,
+                          circpad_machine_spec_t *, m) {
+    machine_spec_free(m);
+  } SMARTLIST_FOREACH_END(m);
+
+  smartlist_free(origin_padding_machines);
+  smartlist_free(relay_padding_machines);
+
+  UNMOCK(circuitmux_attach_circuit);
+  UNMOCK(circuit_package_relay_cell);
+  UNMOCK(circuit_get_nth_node);
+  UNMOCK(circpad_machine_schedule_padding);
 }
 
 #define TEST_CIRCUITPADDING(name, flags) \
@@ -2112,17 +3157,23 @@ test_circuitpadding_global_rate_limiting(void *arg)
 
 struct testcase_t circuitpadding_tests[] = {
   TEST_CIRCUITPADDING(circuitpadding_tokens, TT_FORK),
+  TEST_CIRCUITPADDING(circuitpadding_state_length, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_negotiation, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_wronghop, TT_FORK),
+  /** Disabled unstable test until #29298 is implemented (see #29122) */
+  //  TEST_CIRCUITPADDING(circuitpadding_circuitsetup_machine, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_conditions, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_rtt, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_sample_distribution, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_machine_rate_limiting, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_global_rate_limiting, TT_FORK),
+  TEST_CIRCUITPADDING(circuitpadding_reduce_disable, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_token_removal_lower, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_token_removal_higher, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_closest_token_removal, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_closest_token_removal_usec, TT_FORK),
   TEST_CIRCUITPADDING(circuitpadding_token_removal_exact, TT_FORK),
+  TEST_CIRCUITPADDING(circuitpadding_manage_circuit_lifetime, TT_FORK),
+  TEST_CIRCUITPADDING(circuitpadding_hs_machines, TT_FORK),
   END_OF_TESTCASES
 };
diff --git a/src/test/test_circuitstats.c b/src/test/test_circuitstats.c
index 1cbcb14f2..2a09622f0 100644
--- a/src/test/test_circuitstats.c
+++ b/src/test/test_circuitstats.c
@@ -28,7 +28,7 @@ origin_circuit_t *subtest_fourhop_circuit(struct timeval, int);
 origin_circuit_t *add_opened_threehop(void);
 origin_circuit_t *build_unopened_fourhop(struct timeval);
 
-int onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice);
+int cpath_append_hop(crypt_path_t **head_ptr, extend_info_t *choice);
 
 static int marked_for_close;
 /* Mock function because we are not trying to test the close circuit that does
@@ -57,9 +57,9 @@ add_opened_threehop(void)
   or_circ->build_state = tor_malloc_zero(sizeof(cpath_build_state_t));
   or_circ->build_state->desired_path_len = DEFAULT_ROUTE_LEN;
 
-  onion_append_hop(&or_circ->cpath, &fakehop);
-  onion_append_hop(&or_circ->cpath, &fakehop);
-  onion_append_hop(&or_circ->cpath, &fakehop);
+  cpath_append_hop(&or_circ->cpath, &fakehop);
+  cpath_append_hop(&or_circ->cpath, &fakehop);
+  cpath_append_hop(&or_circ->cpath, &fakehop);
 
   or_circ->has_opened = 1;
   TO_CIRCUIT(or_circ)->state = CIRCUIT_STATE_OPEN;
@@ -82,10 +82,10 @@ build_unopened_fourhop(struct timeval circ_start_time)
   or_circ->build_state = tor_malloc_zero(sizeof(cpath_build_state_t));
   or_circ->build_state->desired_path_len = 4;
 
-  onion_append_hop(&or_circ->cpath, fakehop);
-  onion_append_hop(&or_circ->cpath, fakehop);
-  onion_append_hop(&or_circ->cpath, fakehop);
-  onion_append_hop(&or_circ->cpath, fakehop);
+  cpath_append_hop(&or_circ->cpath, fakehop);
+  cpath_append_hop(&or_circ->cpath, fakehop);
+  cpath_append_hop(&or_circ->cpath, fakehop);
+  cpath_append_hop(&or_circ->cpath, fakehop);
 
   tor_free(fakehop);
 
diff --git a/src/test/test_config.c b/src/test/test_config.c
index 72649dd9b..a415ca448 100644
--- a/src/test/test_config.c
+++ b/src/test/test_config.c
@@ -4569,16 +4569,14 @@ test_config_parse_port_config__ports__ports_given(void *data)
                           "127.0.0.44", 0, CL_PORT_NO_STREAM_OPTIONS);
   tt_int_op(ret, OP_EQ, -1);
 
-  // TODO: this seems wrong. Shouldn't it be the other way around?
-  // Potential bug.
-  // Test failure for a SessionGroup argument with valid value but with stream
-  // options allowed
+  // Test failure for a SessionGroup argument with valid value but with no
+  // stream options allowed
   config_free_lines(config_port_invalid); config_port_invalid = NULL;
   SMARTLIST_FOREACH(slout,port_cfg_t *,pf,port_cfg_free(pf));
   smartlist_clear(slout);
   config_port_invalid = mock_config_line("DNSPort", "42 SessionGroup=123");
   ret = parse_port_config(slout, config_port_invalid, "DNS", 0,
-                          "127.0.0.44", 0, 0);
+                          "127.0.0.44", 0, CL_PORT_NO_STREAM_OPTIONS);
   tt_int_op(ret, OP_EQ, -1);
 
   // Test failure for more than one SessionGroup argument
@@ -4588,7 +4586,7 @@ test_config_parse_port_config__ports__ports_given(void *data)
   config_port_invalid = mock_config_line("DNSPort", "42 SessionGroup=123 "
                                          "SessionGroup=321");
   ret = parse_port_config(slout, config_port_invalid, "DNS", 0,
-                          "127.0.0.44", 0, CL_PORT_NO_STREAM_OPTIONS);
+                          "127.0.0.44", 0, 0);
   tt_int_op(ret, OP_EQ, -1);
 
   // Test success with a sessiongroup options
@@ -4597,7 +4595,7 @@ test_config_parse_port_config__ports__ports_given(void *data)
   smartlist_clear(slout);
   config_port_valid = mock_config_line("DNSPort", "42 SessionGroup=1111122");
   ret = parse_port_config(slout, config_port_valid, "DNS", 0,
-                          "127.0.0.44", 0, CL_PORT_NO_STREAM_OPTIONS);
+                          "127.0.0.44", 0, 0);
   tt_int_op(ret, OP_EQ, 0);
   tt_int_op(smartlist_len(slout), OP_EQ, 1);
   port_cfg = (port_cfg_t *)smartlist_get(slout, 0);
@@ -5066,7 +5064,7 @@ test_config_include_no_permission(void *data)
     chmod(dir, 0700);
   tor_free(dir);
 }
-#endif
+#endif /* !defined(_WIN32) */
 
 static void
 test_config_include_recursion_before_after(void *data)
@@ -5698,7 +5696,7 @@ test_config_compute_max_mem_in_queues(void *data)
 #else
   /* We are on a 32-bit system. */
   tt_u64_op(compute_real_max_mem_in_queues(0, 0), OP_EQ, GIGABYTE(1));
-#endif
+#endif /* SIZEOF_VOID_P >= 8 */
 
   /* We are able to detect the amount of RAM on the system. */
   total_system_memory_return = 0;
@@ -5739,7 +5737,7 @@ test_config_compute_max_mem_in_queues(void *data)
   /* We will at maximum get MAX_DEFAULT_MEMORY_QUEUE_SIZE here. */
   tt_u64_op(compute_real_max_mem_in_queues(0, 0), OP_EQ,
             MAX_DEFAULT_MEMORY_QUEUE_SIZE);
-#endif
+#endif /* SIZEOF_SIZE_T > 4 */
 
  done:
   UNMOCK(get_total_system_memory);
@@ -5886,6 +5884,61 @@ test_config_kvline_parse(void *arg)
   tt_assert(lines);
   tt_str_op(lines->key, OP_EQ, "AB");
   tt_str_op(lines->value, OP_EQ, "");
+  config_free_lines(lines);
+
+  lines = kvline_parse("AB=", KV_OMIT_VALS);
+  tt_assert(lines);
+  tt_str_op(lines->key, OP_EQ, "AB");
+  tt_str_op(lines->value, OP_EQ, "");
+  config_free_lines(lines);
+
+  lines = kvline_parse(" AB ", KV_OMIT_VALS);
+  tt_assert(lines);
+  tt_str_op(lines->key, OP_EQ, "AB");
+  tt_str_op(lines->value, OP_EQ, "");
+  config_free_lines(lines);
+
+  lines = kvline_parse("AB", KV_OMIT_VALS);
+  tt_assert(lines);
+  tt_str_op(lines->key, OP_EQ, "AB");
+  tt_str_op(lines->value, OP_EQ, "");
+  enc = kvline_encode(lines, KV_OMIT_VALS);
+  tt_str_op(enc, OP_EQ, "AB");
+  tor_free(enc);
+  config_free_lines(lines);
+
+  lines = kvline_parse("AB=CD", KV_OMIT_VALS);
+  tt_assert(lines);
+  tt_str_op(lines->key, OP_EQ, "AB");
+  tt_str_op(lines->value, OP_EQ, "CD");
+  enc = kvline_encode(lines, KV_OMIT_VALS);
+  tt_str_op(enc, OP_EQ, "AB=CD");
+  tor_free(enc);
+  config_free_lines(lines);
+
+  lines = kvline_parse("AB=CD DE FGH=I", KV_OMIT_VALS);
+  tt_assert(lines);
+  tt_str_op(lines->key, OP_EQ, "AB");
+  tt_str_op(lines->value, OP_EQ, "CD");
+  tt_str_op(lines->next->key, OP_EQ, "DE");
+  tt_str_op(lines->next->value, OP_EQ, "");
+  tt_str_op(lines->next->next->key, OP_EQ, "FGH");
+  tt_str_op(lines->next->next->value, OP_EQ, "I");
+  enc = kvline_encode(lines, KV_OMIT_VALS);
+  tt_str_op(enc, OP_EQ, "AB=CD DE FGH=I");
+  tor_free(enc);
+  config_free_lines(lines);
+
+  lines = kvline_parse("AB=\"CD E\" DE FGH=\"I\"", KV_OMIT_VALS|KV_QUOTED);
+  tt_assert(lines);
+  tt_str_op(lines->key, OP_EQ, "AB");
+  tt_str_op(lines->value, OP_EQ, "CD E");
+  tt_str_op(lines->next->key, OP_EQ, "DE");
+  tt_str_op(lines->next->value, OP_EQ, "");
+  tt_str_op(lines->next->next->key, OP_EQ, "FGH");
+  tt_str_op(lines->next->next->value, OP_EQ, "I");
+  enc = kvline_encode(lines, KV_OMIT_VALS|KV_QUOTED);
+  tt_str_op(enc, OP_EQ, "AB=\"CD E\" DE FGH=I");
 
  done:
   config_free_lines(lines);
diff --git a/src/test/test_connection.h b/src/test/test_connection.h
index 47a5599e5..40121e6d3 100644
--- a/src/test/test_connection.h
+++ b/src/test/test_connection.h
@@ -1,6 +1,9 @@
 /* Copyright (c) 2014-2019, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+#ifndef TOR_TEST_CONNECTION_H
+#define TOR_TEST_CONNECTION_H
+
 /** Some constants used by test_connection and helpers */
 #define TEST_CONN_FAMILY        (AF_INET)
 #define TEST_CONN_ADDRESS       "127.0.0.1"
@@ -11,3 +14,4 @@
 void test_conn_lookup_addr_helper(const char *address,
                                   int family, tor_addr_t *addr);
 
+#endif /* !defined(TOR_TEST_CONNECTION_H) */
diff --git a/src/test/test_containers.c b/src/test/test_containers.c
index a0832f868..67ba45797 100644
--- a/src/test/test_containers.c
+++ b/src/test/test_containers.c
@@ -606,6 +606,66 @@ test_container_smartlist_ints_eq(void *arg)
   smartlist_free(sl2);
 }
 
+static void
+test_container_smartlist_grow(void *arg)
+{
+  (void)arg;
+  smartlist_t *sl = smartlist_new();
+  int i;
+  const char *s[] = { "first", "2nd", "3rd" };
+
+  /* case 1: starting from empty. */
+  smartlist_grow(sl, 10);
+  tt_int_op(10, OP_EQ, smartlist_len(sl));
+  for (i = 0; i < 10; ++i) {
+    tt_ptr_op(smartlist_get(sl, i), OP_EQ, NULL);
+  }
+
+  /* case 2: starting with a few elements, probably not reallocating. */
+  smartlist_free(sl);
+  sl = smartlist_new();
+  smartlist_add(sl, (char*)s[0]);
+  smartlist_add(sl, (char*)s[1]);
+  smartlist_add(sl, (char*)s[2]);
+  smartlist_grow(sl, 5);
+  tt_int_op(5, OP_EQ, smartlist_len(sl));
+  for (i = 0; i < 3; ++i) {
+    tt_ptr_op(smartlist_get(sl, i), OP_EQ, s[i]);
+  }
+  tt_ptr_op(smartlist_get(sl, 3), OP_EQ, NULL);
+  tt_ptr_op(smartlist_get(sl, 4), OP_EQ, NULL);
+
+  /* case 3: starting with a few elements, but reallocating. */
+  smartlist_free(sl);
+  sl = smartlist_new();
+  smartlist_add(sl, (char*)s[0]);
+  smartlist_add(sl, (char*)s[1]);
+  smartlist_add(sl, (char*)s[2]);
+  smartlist_grow(sl, 100);
+  tt_int_op(100, OP_EQ, smartlist_len(sl));
+  for (i = 0; i < 3; ++i) {
+    tt_ptr_op(smartlist_get(sl, i), OP_EQ, s[i]);
+  }
+  for (i = 3; i < 100; ++i) {
+    tt_ptr_op(smartlist_get(sl, i), OP_EQ, NULL);
+  }
+
+  /* case 4: shrinking doesn't happen. */
+  smartlist_free(sl);
+  sl = smartlist_new();
+  smartlist_add(sl, (char*)s[0]);
+  smartlist_add(sl, (char*)s[1]);
+  smartlist_add(sl, (char*)s[2]);
+  smartlist_grow(sl, 1);
+  tt_int_op(3, OP_EQ, smartlist_len(sl));
+  for (i = 0; i < 3; ++i) {
+    tt_ptr_op(smartlist_get(sl, i), OP_EQ, s[i]);
+  }
+
+ done:
+  smartlist_free(sl);
+}
+
 /** Run unit tests for bitarray code */
 static void
 test_container_bitarray(void *arg)
@@ -946,6 +1006,10 @@ test_container_smartlist_remove(void *arg)
   tt_ptr_op(smartlist_get(sl, 1), OP_EQ, &array[2]);
   tt_ptr_op(smartlist_get(sl, 2), OP_EQ, &array[1]);
   tt_ptr_op(smartlist_get(sl, 3), OP_EQ, &array[2]);
+  /* Ordinary code should never look at this pointer; we're doing it here
+   * to make sure that we really cleared the pointer we removed.
+   */
+  tt_ptr_op(sl->list[4], OP_EQ, NULL);
 
  done:
   smartlist_free(sl);
@@ -1312,6 +1376,7 @@ struct testcase_t container_tests[] = {
   CONTAINER_LEGACY(smartlist_pos),
   CONTAINER(smartlist_remove, 0),
   CONTAINER(smartlist_ints_eq, 0),
+  CONTAINER(smartlist_grow, 0),
   CONTAINER_LEGACY(bitarray),
   CONTAINER_LEGACY(digestset),
   CONTAINER_LEGACY(strmap),
diff --git a/src/test/test_controller.c b/src/test/test_controller.c
index 5b406e159..ee48d656b 100644
--- a/src/test/test_controller.c
+++ b/src/test/test_controller.c
@@ -1,11 +1,14 @@
 /* Copyright (c) 2015-2019, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
-#define CONTROL_PRIVATE
+#define CONTROL_CMD_PRIVATE
+#define CONTROL_GETINFO_PRIVATE
 #include "core/or/or.h"
 #include "lib/crypt_ops/crypto_ed25519.h"
 #include "feature/client/bridges.h"
 #include "feature/control/control.h"
+#include "feature/control/control_cmd.h"
+#include "feature/control/control_getinfo.h"
 #include "feature/client/entrynodes.h"
 #include "feature/hs/hs_common.h"
 #include "feature/nodelist/networkstatus.h"
@@ -15,12 +18,189 @@
 #include "test/test.h"
 #include "test/test_helpers.h"
 #include "lib/net/resolve.h"
+#include "lib/encoding/confline.h"
+#include "lib/encoding/kvline.h"
 
 #include "feature/control/control_connection_st.h"
+#include "feature/control/control_cmd_args_st.h"
 #include "feature/dirclient/download_status_st.h"
 #include "feature/nodelist/microdesc_st.h"
 #include "feature/nodelist/node_st.h"
 
+typedef struct {
+  const char *input;
+  const char *expected_parse;
+  const char *expected_error;
+} parser_testcase_t;
+
+typedef struct {
+  const control_cmd_syntax_t *syntax;
+  size_t n_testcases;
+  const parser_testcase_t *testcases;
+} parse_test_params_t;
+
+static char *
+control_cmd_dump_args(const control_cmd_args_t *result)
+{
+  buf_t *buf = buf_new();
+  buf_add_string(buf, "{ args=[");
+  if (result->args) {
+    if (smartlist_len(result->args)) {
+        buf_add_string(buf, " ");
+    }
+    SMARTLIST_FOREACH_BEGIN(result->args, const char *, s) {
+      const bool last = (s_sl_idx == smartlist_len(result->args)-1);
+      buf_add_printf(buf, "%s%s ",
+                     escaped(s),
+                     last ? "" : ",");
+    } SMARTLIST_FOREACH_END(s);
+  }
+  buf_add_string(buf, "]");
+  if (result->cmddata) {
+    buf_add_string(buf, ", obj=");
+    buf_add_string(buf, escaped(result->cmddata));
+  }
+  if (result->kwargs) {
+    buf_add_string(buf, ", { ");
+    const config_line_t *line;
+    for (line = result->kwargs; line; line = line->next) {
+      const bool last = (line->next == NULL);
+      buf_add_printf(buf, "%s=%s%s ", line->key, escaped(line->value),
+                     last ? "" : ",");
+    }
+    buf_add_string(buf, "}");
+  }
+  buf_add_string(buf, " }");
+
+  char *encoded = buf_extract(buf, NULL);
+  buf_free(buf);
+  return encoded;
+}
+
+static void
+test_controller_parse_cmd(void *arg)
+{
+  const parse_test_params_t *params = arg;
+  control_cmd_args_t *result = NULL;
+  char *error = NULL;
+  char *encoded = NULL;
+
+  for (size_t i = 0; i < params->n_testcases; ++i) {
+    const parser_testcase_t *t = ¶ms->testcases[i];
+    result = control_cmd_parse_args("EXAMPLE",
+                                    params->syntax,
+                                    strlen(t->input),
+                                    t->input,
+                                    &error);
+    // A valid test should expect exactly one parse or error.
+    tt_int_op((t->expected_parse == NULL), OP_NE,
+              (t->expected_error == NULL));
+    // We get a result or an error, not both.
+    tt_int_op((result == NULL), OP_EQ, (error != NULL));
+    // We got the one we expected.
+    tt_int_op((result == NULL), OP_EQ, (t->expected_parse == NULL));
+
+    if (result) {
+      encoded = control_cmd_dump_args(result);
+      tt_str_op(encoded, OP_EQ, t->expected_parse);
+    } else {
+      tt_str_op(error, OP_EQ, t->expected_error);
+    }
+
+    tor_free(error);
+    tor_free(encoded);
+    control_cmd_args_free(result);
+  }
+
+ done:
+  tor_free(error);
+  tor_free(encoded);
+  control_cmd_args_free(result);
+}
+
+#define OK(inp, out) \
+  { inp "\r\n", out, NULL }
+#define ERR(inp, err) \
+  { inp "\r\n", NULL, err }
+
+#define TESTPARAMS(syntax, array)                \
+  { &syntax,                                     \
+      ARRAY_LENGTH(array),                       \
+      array }
+
+static const parser_testcase_t one_to_three_tests[] = {
+   ERR("", "Need at least 1 argument(s)"),
+   ERR("   \t", "Need at least 1 argument(s)"),
+   OK("hello", "{ args=[ \"hello\" ] }"),
+   OK("hello world", "{ args=[ \"hello\", \"world\" ] }"),
+   OK("hello  world", "{ args=[ \"hello\", \"world\" ] }"),
+   OK("  hello  world", "{ args=[ \"hello\", \"world\" ] }"),
+   OK("  hello  world      ", "{ args=[ \"hello\", \"world\" ] }"),
+   OK("hello there world", "{ args=[ \"hello\", \"there\", \"world\" ] }"),
+   ERR("why hello there world", "Cannot accept more than 3 argument(s)"),
+   ERR("hello\r\nworld.\r\n.", "Unexpected body"),
+};
+
+static const control_cmd_syntax_t one_to_three_syntax = {
+   .min_args=1, .max_args=3
+};
+
+static const parse_test_params_t parse_one_to_three_params =
+  TESTPARAMS( one_to_three_syntax, one_to_three_tests );
+
+// =
+static const parser_testcase_t no_args_one_obj_tests[] = {
+  ERR("Hi there!\r\n.", "Cannot accept more than 0 argument(s)"),
+  ERR("", "Empty body"),
+  OK("\r\n", "{ args=[], obj=\"\\n\" }"),
+  OK("\r\nHello world\r\n", "{ args=[], obj=\"Hello world\\n\\n\" }"),
+  OK("\r\nHello\r\nworld\r\n", "{ args=[], obj=\"Hello\\nworld\\n\\n\" }"),
+  OK("\r\nHello\r\n..\r\nworld\r\n",
+     "{ args=[], obj=\"Hello\\n.\\nworld\\n\\n\" }"),
+};
+static const control_cmd_syntax_t no_args_one_obj_syntax = {
+   .min_args=0, .max_args=0,
+   .want_cmddata=true,
+};
+static const parse_test_params_t parse_no_args_one_obj_params =
+  TESTPARAMS( no_args_one_obj_syntax, no_args_one_obj_tests );
+
+static const parser_testcase_t no_args_kwargs_tests[] = {
+  OK("", "{ args=[] }"),
+  OK(" ", "{ args=[] }"),
+  OK("hello there=world", "{ args=[], { hello=\"\", there=\"world\" } }"),
+  OK("hello there=world today",
+     "{ args=[], { hello=\"\", there=\"world\", today=\"\" } }"),
+  ERR("=Foo", "Cannot parse keyword argument(s)"),
+};
+static const control_cmd_syntax_t no_args_kwargs_syntax = {
+   .min_args=0, .max_args=0,
+   .accept_keywords=true,
+   .kvline_flags=KV_OMIT_VALS
+};
+static const parse_test_params_t parse_no_args_kwargs_params =
+  TESTPARAMS( no_args_kwargs_syntax, no_args_kwargs_tests );
+
+static const char *one_arg_kwargs_allow_keywords[] = {
+  "Hello", "world", NULL
+};
+static const parser_testcase_t one_arg_kwargs_tests[] = {
+  ERR("", "Need at least 1 argument(s)"),
+  OK("Hi", "{ args=[ \"Hi\" ] }"),
+  ERR("hello there=world", "Unrecognized keyword argument \"there\""),
+  OK("Hi HELLO=foo", "{ args=[ \"Hi\" ], { HELLO=\"foo\" } }"),
+  OK("Hi world=\"bar baz\" hello  ",
+     "{ args=[ \"Hi\" ], { world=\"bar baz\", hello=\"\" } }"),
+};
+static const control_cmd_syntax_t one_arg_kwargs_syntax = {
+   .min_args=1, .max_args=1,
+   .accept_keywords=true,
+   .allowed_keywords=one_arg_kwargs_allow_keywords,
+   .kvline_flags=KV_OMIT_VALS|KV_QUOTED,
+};
+static const parse_test_params_t parse_one_arg_kwargs_params =
+  TESTPARAMS( one_arg_kwargs_syntax, one_arg_kwargs_tests );
+
 static void
 test_add_onion_helper_keyarg_v3(void *arg)
 {
@@ -1543,7 +1723,7 @@ test_current_time(void *arg)
 static size_t n_nodelist_get_list = 0;
 static smartlist_t *nodes = NULL;
 
-static smartlist_t *
+static const smartlist_t *
 mock_nodelist_get_list(void)
 {
   n_nodelist_get_list++;
@@ -1614,7 +1794,15 @@ test_getinfo_md_all(void *arg)
   return;
 }
 
+#define PARSER_TEST(type)                                             \
+  { "parse/" #type, test_controller_parse_cmd, 0, &passthrough_setup, \
+      (void*)&parse_ ## type ## _params }
+
 struct testcase_t controller_tests[] = {
+  PARSER_TEST(one_to_three),
+  PARSER_TEST(no_args_one_obj),
+  PARSER_TEST(no_args_kwargs),
+  PARSER_TEST(one_arg_kwargs),
   { "add_onion_helper_keyarg_v2", test_add_onion_helper_keyarg_v2, 0,
     NULL, NULL },
   { "add_onion_helper_keyarg_v3", test_add_onion_helper_keyarg_v3, 0,
diff --git a/src/test/test_controller_events.c b/src/test/test_controller_events.c
index 647eac43c..910aacace 100644
--- a/src/test/test_controller_events.c
+++ b/src/test/test_controller_events.c
@@ -4,6 +4,7 @@
 #define CONNECTION_PRIVATE
 #define TOR_CHANNEL_INTERNAL_
 #define CONTROL_PRIVATE
+#define CONTROL_EVENTS_PRIVATE
 #define OCIRC_EVENT_PRIVATE
 #define ORCONN_EVENT_PRIVATE
 #include "core/or/or.h"
@@ -13,7 +14,7 @@
 #include "core/or/ocirc_event.h"
 #include "core/or/orconn_event.h"
 #include "core/mainloop/connection.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "test/test.h"
 
 #include "core/or/or_circuit_st.h"
diff --git a/src/test/test_crypto.c b/src/test/test_crypto.c
index 0b57448bc..178a9a509 100644
--- a/src/test/test_crypto.c
+++ b/src/test/test_crypto.c
@@ -32,7 +32,7 @@
 DISABLE_GCC_WARNING(redundant-decls)
 #include <openssl/dh.h>
 ENABLE_GCC_WARNING(redundant-decls)
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 /** Run unit tests for Diffie-Hellman functionality. */
 static void
@@ -190,7 +190,7 @@ test_crypto_dh(void *arg)
     DH_get0_key(dh4, &pk, &sk);
 #else
     pk = dh4->pub_key;
-#endif
+#endif /* defined(OPENSSL_1_1_API) */
     tt_assert(pk);
     tt_int_op(BN_num_bytes(pk), OP_LE, DH1024_KEY_LEN);
     tt_int_op(BN_num_bytes(pk), OP_GT, 0);
@@ -207,7 +207,7 @@ test_crypto_dh(void *arg)
     tt_int_op(s1len, OP_GT, 0);
     tt_mem_op(s1, OP_EQ, s2, s1len);
   }
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
  done:
   crypto_dh_free(dh1);
@@ -219,7 +219,7 @@ test_crypto_dh(void *arg)
     DH_free(dh4);
   if (pubkey_tmp)
     BN_free(pubkey_tmp);
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 }
 
 static void
@@ -248,7 +248,7 @@ test_crypto_openssl_version(void *arg)
   tt_int_op(a, OP_GE, 0);
   tt_int_op(b, OP_GE, 0);
   tt_int_op(c, OP_GE, 0);
-#endif
+#endif /* defined(ENABLE_NSS) */
 
  done:
   ;
@@ -389,7 +389,7 @@ test_crypto_aes128(void *arg)
                                    "\xff\xff\xff\xff\xff\xff\xff\xff"
                                    "\xff\xff\xff\xff\xff\xff\xff\xff");
   crypto_cipher_crypt_inplace(env1, data2, 64);
-  tt_assert(tor_mem_is_zero(data2, 64));
+  tt_assert(fast_mem_is_zero(data2, 64));
 
  done:
   tor_free(mem_op_hex_tmp);
@@ -1011,13 +1011,19 @@ test_crypto_sha3_xof(void *arg)
   crypto_xof_free(xof);
   memset(out, 0, sizeof(out));
 
+  /* Test one-function absorb/squeeze. */
+  crypto_xof(out, sizeof(out), msg, sizeof(msg));
+  test_memeq_hex(out, squeezed_hex);
+  memset(out, 0, sizeof(out));
+
   /* Test incremental absorb/squeeze. */
   xof = crypto_xof_new();
   tt_assert(xof);
   for (size_t i = 0; i < sizeof(msg); i++)
     crypto_xof_add_bytes(xof, msg + i, 1);
-  for (size_t i = 0; i < sizeof(out); i++)
+  for (size_t i = 0; i < sizeof(out); i++) {
     crypto_xof_squeeze_bytes(xof, out + i, 1);
+  }
   test_memeq_hex(out, squeezed_hex);
 
  done:
@@ -1703,13 +1709,13 @@ test_crypto_base32_decode(void *arg)
   /* Encode and decode a random string. */
   base32_encode(encoded, 96 + 1, plain, 60);
   res = base32_decode(decoded, 60, encoded, 96);
-  tt_int_op(res,OP_EQ, 0);
+  tt_int_op(res, OP_EQ, 60);
   tt_mem_op(plain,OP_EQ, decoded, 60);
   /* Encode, uppercase, and decode a random string. */
   base32_encode(encoded, 96 + 1, plain, 60);
   tor_strupper(encoded);
   res = base32_decode(decoded, 60, encoded, 96);
-  tt_int_op(res,OP_EQ, 0);
+  tt_int_op(res, OP_EQ, 60);
   tt_mem_op(plain,OP_EQ, decoded, 60);
   /* Change encoded string and decode. */
   if (encoded[0] == 'A' || encoded[0] == 'a')
@@ -1717,12 +1723,12 @@ test_crypto_base32_decode(void *arg)
   else
     encoded[0] = 'A';
   res = base32_decode(decoded, 60, encoded, 96);
-  tt_int_op(res,OP_EQ, 0);
+  tt_int_op(res, OP_EQ, 60);
   tt_mem_op(plain,OP_NE, decoded, 60);
   /* Bad encodings. */
   encoded[0] = '!';
   res = base32_decode(decoded, 60, encoded, 96);
-  tt_int_op(0, OP_GT, res);
+  tt_int_op(res, OP_LT, 0);
 
  done:
   ;
@@ -2069,7 +2075,7 @@ test_crypto_curve25519_encode(void *arg)
 
   curve25519_secret_key_generate(&seckey, 0);
   curve25519_public_key_generate(&key1, &seckey);
-  tt_int_op(0, OP_EQ, curve25519_public_to_base64(buf, &key1));
+  curve25519_public_to_base64(buf, &key1);
   tt_int_op(CURVE25519_BASE64_PADDED_LEN, OP_EQ, strlen(buf));
 
   tt_int_op(0, OP_EQ, curve25519_public_from_base64(&key2, buf));
@@ -2128,7 +2134,7 @@ test_crypto_curve25519_persist(void *arg)
   tt_u64_op((uint64_t)st.st_size, OP_EQ,
             32+CURVE25519_PUBKEY_LEN+CURVE25519_SECKEY_LEN);
   tt_assert(fast_memeq(content, "== c25519v1: testing ==", taglen));
-  tt_assert(tor_mem_is_zero(content+taglen, 32-taglen));
+  tt_assert(fast_mem_is_zero(content+taglen, 32-taglen));
   cp = content + 32;
   tt_mem_op(keypair.seckey.secret_key,OP_EQ,
              cp,
@@ -2449,13 +2455,13 @@ test_crypto_ed25519_encode(void *arg)
 
   /* Test roundtrip. */
   tt_int_op(0, OP_EQ, ed25519_keypair_generate(&kp, 0));
-  tt_int_op(0, OP_EQ, ed25519_public_to_base64(buf, &kp.pubkey));
+  ed25519_public_to_base64(buf, &kp.pubkey);
   tt_int_op(ED25519_BASE64_LEN, OP_EQ, strlen(buf));
   tt_int_op(0, OP_EQ, ed25519_public_from_base64(&pk, buf));
   tt_mem_op(kp.pubkey.pubkey, OP_EQ, pk.pubkey, ED25519_PUBKEY_LEN);
 
   tt_int_op(0, OP_EQ, ed25519_sign(&sig1, (const uint8_t*)"ABC", 3, &kp));
-  tt_int_op(0, OP_EQ, ed25519_signature_to_base64(buf, &sig1));
+  ed25519_signature_to_base64(buf, &sig1);
   tt_int_op(0, OP_EQ, ed25519_signature_from_base64(&sig2, buf));
   tt_mem_op(sig1.sig, OP_EQ, sig2.sig, ED25519_SIG_LEN);
 
diff --git a/src/test/test_crypto_rng.c b/src/test/test_crypto_rng.c
index 23b0c6651..6b7749a88 100644
--- a/src/test/test_crypto_rng.c
+++ b/src/test/test_crypto_rng.c
@@ -218,6 +218,14 @@ test_crypto_rng_fast(void *arg)
     tt_int_op(counts[i], OP_GT, 0);
   }
 
+  /* per-thread rand_fast shouldn't crash or leak. */
+  crypto_fast_rng_t *t_rng = get_thread_fast_rng();
+  for (int i = 0; i < N; ++i) {
+    uint64_t u64 = crypto_fast_rng_get_uint64(t_rng, UINT64_C(1)<<40);
+    tt_u64_op(u64, OP_GE, 0);
+    tt_u64_op(u64, OP_LT, UINT64_C(1)<<40);
+  }
+
  done:
   crypto_fast_rng_free(rng);
 }
diff --git a/src/test/test_crypto_slow.c b/src/test/test_crypto_slow.c
index e24aee893..3b20dfa58 100644
--- a/src/test/test_crypto_slow.c
+++ b/src/test/test_crypto_slow.c
@@ -109,7 +109,7 @@ run_s2k_tests(const unsigned flags, const unsigned type,
             secret_to_key_derivekey(buf3, sizeof(buf3), buf, speclen,
                                     pw1, strlen(pw1)));
   tt_mem_op(buf2, OP_EQ, buf3, sizeof(buf3));
-  tt_assert(!tor_mem_is_zero((char*)buf2+keylen, sizeof(buf2)-keylen));
+  tt_assert(!fast_mem_is_zero((char*)buf2+keylen, sizeof(buf2)-keylen));
 
  done:
   ;
diff --git a/src/test/test_dir.c b/src/test/test_dir.c
index 07a2641c9..17d6db1e4 100644
--- a/src/test/test_dir.c
+++ b/src/test/test_dir.c
@@ -8,7 +8,7 @@
 
 #define BWAUTH_PRIVATE
 #define CONFIG_PRIVATE
-#define CONTROL_PRIVATE
+#define CONTROL_GETINFO_PRIVATE
 #define DIRCACHE_PRIVATE
 #define DIRCLIENT_PRIVATE
 #define DIRSERV_PRIVATE
@@ -32,7 +32,7 @@
 #include "core/or/versions.h"
 #include "feature/client/bridges.h"
 #include "feature/client/entrynodes.h"
-#include "feature/control/control.h"
+#include "feature/control/control_getinfo.h"
 #include "feature/dirauth/bwauth.h"
 #include "feature/dirauth/dirvote.h"
 #include "feature/dirauth/dsigs_parse.h"
@@ -162,6 +162,269 @@ test_dir_nicknames(void *arg)
   ;
 }
 
+/* Allocate and return a new routerinfo, with the fields set from the
+ * arguments to this function.
+ *
+ * Also sets:
+ *  - random RSA identity and onion keys,
+ *  - the platform field using get_platform_str(), and
+ *  - supports_tunnelled_dir_requests to 1.
+ *
+ * If rsa_onion_keypair_out is not NULL, it is set to the onion keypair.
+ * The caller must free this keypair.
+ */
+static routerinfo_t *
+basic_routerinfo_new(const char *nickname, uint32_t ipv4_addr,
+                     uint16_t or_port, uint16_t dir_port,
+                     uint32_t bandwidthrate, uint32_t bandwidthburst,
+                     uint32_t bandwidthcapacity,
+                     time_t published_on,
+                     crypto_pk_t **rsa_onion_keypair_out)
+{
+  char platform[256];
+
+  tor_assert(nickname);
+
+  crypto_pk_t *pk1 = NULL, *pk2 = NULL;
+  /* These keys are random: idx is ignored. */
+  pk1 = pk_generate(0);
+  pk2 = pk_generate(1);
+
+  tor_assert(pk1);
+  tor_assert(pk2);
+
+  get_platform_str(platform, sizeof(platform));
+
+  routerinfo_t *r1 = tor_malloc_zero(sizeof(routerinfo_t));
+
+  r1->nickname = tor_strdup(nickname);
+  r1->platform = tor_strdup(platform);
+
+  r1->addr = ipv4_addr;
+  r1->or_port = or_port;
+  r1->dir_port = dir_port;
+  r1->supports_tunnelled_dir_requests = 1;
+
+  router_set_rsa_onion_pkey(pk1, &r1->onion_pkey, &r1->onion_pkey_len);
+  r1->identity_pkey = pk2;
+
+  r1->bandwidthrate = bandwidthrate;
+  r1->bandwidthburst = bandwidthburst;
+  r1->bandwidthcapacity = bandwidthcapacity;
+
+  r1->cache_info.published_on = published_on;
+
+  if (rsa_onion_keypair_out) {
+    *rsa_onion_keypair_out = pk1;
+  } else {
+    crypto_pk_free(pk1);
+  }
+
+  return r1;
+}
+
+/* Allocate and return a new string containing a "router" line for r1. */
+static char *
+get_new_router_line(const routerinfo_t *r1)
+{
+  char *line = NULL;
+
+  tor_assert(r1);
+
+  tor_asprintf(&line,
+               "router %s %s %d 0 %d\n",
+               r1->nickname, fmt_addr32(r1->addr),
+               r1->or_port, r1->dir_port);
+  tor_assert(line);
+
+  return line;
+}
+
+/* Allocate and return a new string containing a "platform" line for the
+ * current Tor version and OS. */
+static char *
+get_new_platform_line(void)
+{
+  char *line = NULL;
+
+  tor_asprintf(&line,
+               "platform Tor %s on %s\n",
+               VERSION, get_uname());
+  tor_assert(line);
+
+  return line;
+}
+
+/* Allocate and return a new string containing a "published" line for r1.
+ * r1->cache_info.published_on must be between 0 and 59 seconds. */
+static char *
+get_new_published_line(const routerinfo_t *r1)
+{
+  char *line = NULL;
+
+  tor_assert(r1);
+
+  tor_assert(r1->cache_info.published_on >= 0);
+  tor_assert(r1->cache_info.published_on <= 59);
+
+  tor_asprintf(&line,
+               "published 1970-01-01 00:00:%02u\n",
+               (unsigned)r1->cache_info.published_on);
+  tor_assert(line);
+
+  return line;
+}
+
+/* Allocate and return a new string containing a "fingerprint" line for r1. */
+static char *
+get_new_fingerprint_line(const routerinfo_t *r1)
+{
+  char *line = NULL;
+  char fingerprint[FINGERPRINT_LEN+1];
+
+  tor_assert(r1);
+
+  tor_assert(!crypto_pk_get_fingerprint(r1->identity_pkey, fingerprint, 1));
+  tor_assert(strlen(fingerprint) > 0);
+
+  tor_asprintf(&line,
+               "fingerprint %s\n",
+               fingerprint);
+  tor_assert(line);
+
+  return line;
+}
+
+/* Allocate and return a new string containing an "uptime" line with uptime t.
+ *
+ * You should pass a hard-coded value to this function, because even if we made
+ * it reflect uptime, that still wouldn't make it right, because the two
+ * descriptors might be made on different seconds.
+ */
+static char *
+get_new_uptime_line(time_t t)
+{
+  char *line = NULL;
+
+  tor_asprintf(&line,
+               "uptime %u\n",
+               (unsigned)t);
+  tor_assert(line);
+
+  return line;
+}
+
+/* Allocate and return a new string containing an "bandwidth" line for r1.
+ */
+static char *
+get_new_bandwidth_line(const routerinfo_t *r1)
+{
+  char *line = NULL;
+
+  tor_assert(r1);
+
+  tor_asprintf(&line,
+               "bandwidth %u %u %u\n",
+               r1->bandwidthrate,
+               r1->bandwidthburst,
+               r1->bandwidthcapacity);
+  tor_assert(line);
+
+  return line;
+}
+
+/* Allocate and return a new string containing a key_name block for the
+ * RSA key pk1.
+ */
+static char *
+get_new_rsa_key_block(const char *key_name, crypto_pk_t *pk1)
+{
+  char *block = NULL;
+  char *pk1_str = NULL;
+  size_t pk1_str_len = 0;
+
+  tor_assert(key_name);
+  tor_assert(pk1);
+
+  tor_assert(!crypto_pk_write_public_key_to_string(pk1, &pk1_str,
+                                                   &pk1_str_len));
+  tor_assert(pk1_str);
+  tor_assert(pk1_str_len);
+
+  tor_asprintf(&block,
+               "%s\n%s",
+               key_name,
+               pk1_str);
+  tor_free(pk1_str);
+
+  tor_assert(block);
+  return block;
+}
+
+/* Allocate and return a new string containing an "onion-key" block for the
+ * router r1.
+ */
+static char *
+get_new_onion_key_block(const routerinfo_t *r1)
+{
+  char *block = NULL;
+  tor_assert(r1);
+  crypto_pk_t *pk_tmp = router_get_rsa_onion_pkey(r1->onion_pkey,
+                                                  r1->onion_pkey_len);
+  block = get_new_rsa_key_block("onion-key", pk_tmp);
+  crypto_pk_free(pk_tmp);
+  return block;
+}
+
+/* Allocate and return a new string containing an "signing-key" block for the
+ * router r1.
+ */
+static char *
+get_new_signing_key_block(const routerinfo_t *r1)
+{
+  tor_assert(r1);
+  return get_new_rsa_key_block("signing-key", r1->identity_pkey);
+}
+
+/* Allocate and return a new string containing an "ntor-onion-key" line for
+ * the curve25519 public key ntor_onion_pubkey.
+ */
+static char *
+get_new_ntor_onion_key_line(const curve25519_public_key_t *ntor_onion_pubkey)
+{
+  char *line = NULL;
+  char cert_buf[256];
+  int rv = 0;
+
+  tor_assert(ntor_onion_pubkey);
+
+  rv = base64_encode(cert_buf, sizeof(cert_buf),
+                     (const char*)ntor_onion_pubkey->public_key, 32,
+                     BASE64_ENCODE_MULTILINE);
+  tor_assert(rv > 0);
+  tor_assert(strlen(cert_buf) > 0);
+
+  tor_asprintf(&line,
+               "ntor-onion-key %s",
+               cert_buf);
+  tor_assert(line);
+
+  return line;
+}
+
+/* Allocate and return a new string containing a "bridge-distribution-request"
+ * line for options.
+ */
+static char *
+get_new_bridge_distribution_request_line(const or_options_t *options)
+{
+  if (options->BridgeRelay) {
+    return tor_strdup("bridge-distribution-request any\n");
+  } else {
+    return tor_strdup("");
+  }
+}
+
 static smartlist_t *mocked_configured_ports = NULL;
 
 /** Returns mocked_configured_ports */
@@ -171,71 +434,510 @@ mock_get_configured_ports(void)
   return mocked_configured_ports;
 }
 
-/** Run unit tests for router descriptor generation logic. */
+static tor_cert_t *
+mock_tor_cert_dup_null(const tor_cert_t *cert)
+{
+  (void)cert;
+  return NULL;
+}
+
+static crypto_pk_t *mocked_server_identitykey = NULL;
+
+/* Returns mocked_server_identitykey with no checks. */
+static crypto_pk_t *
+mock_get_server_identity_key(void)
+{
+  return mocked_server_identitykey;
+}
+
+static crypto_pk_t *mocked_onionkey = NULL;
+
+/* Returns mocked_onionkey with no checks. */
+static crypto_pk_t *
+mock_get_onion_key(void)
+{
+  return mocked_onionkey;
+}
+
+static routerinfo_t *mocked_routerinfo = NULL;
+
+/* Returns 0 and sets ri_out to mocked_routerinfo.
+ * ri_out must not be NULL. There are no other checks. */
+static int
+mock_router_build_fresh_unsigned_routerinfo(routerinfo_t **ri_out)
+{
+  tor_assert(ri_out);
+  *ri_out = mocked_routerinfo;
+  return 0;
+}
+
+static ed25519_keypair_t *mocked_master_signing_key = NULL;
+
+/* Returns mocked_master_signing_key with no checks. */
+static const ed25519_keypair_t *
+mock_get_master_signing_keypair(void)
+{
+  return mocked_master_signing_key;
+}
+
+static struct tor_cert_st *mocked_signing_key_cert = NULL;
+
+/* Returns mocked_signing_key_cert with no checks. */
+static const struct tor_cert_st *
+mock_get_master_signing_key_cert(void)
+{
+  return mocked_signing_key_cert;
+}
+
+static curve25519_keypair_t *mocked_curve25519_onion_key = NULL;
+
+/* Returns mocked_curve25519_onion_key with no checks. */
+static const curve25519_keypair_t *
+mock_get_current_curve25519_keypair(void)
+{
+  return mocked_curve25519_onion_key;
+}
+
+/* Unmock get_configured_ports() and free mocked_configured_ports. */
+static void
+cleanup_mock_configured_ports(void)
+{
+  UNMOCK(get_configured_ports);
+
+  if (mocked_configured_ports) {
+    SMARTLIST_FOREACH(mocked_configured_ports, port_cfg_t *, p, tor_free(p));
+    smartlist_free(mocked_configured_ports);
+  }
+}
+
+/* Mock get_configured_ports() with a list containing or_port and dir_port.
+ * If a port is 0, don't set it.
+ * Only sets the minimal data required for the tests to pass. */
+static void
+setup_mock_configured_ports(uint16_t or_port, uint16_t dir_port)
+{
+  cleanup_mock_configured_ports();
+
+  /* Fake just enough of an ORPort and DirPort to get by */
+  MOCK(get_configured_ports, mock_get_configured_ports);
+  mocked_configured_ports = smartlist_new();
+
+  if (or_port) {
+    port_cfg_t *or_port_cfg = tor_malloc_zero(sizeof(*or_port_cfg));
+    or_port_cfg->type = CONN_TYPE_OR_LISTENER;
+    or_port_cfg->addr.family = AF_INET;
+    or_port_cfg->port = or_port;
+    smartlist_add(mocked_configured_ports, or_port_cfg);
+  }
+
+  if (dir_port) {
+    port_cfg_t *dir_port_cfg = tor_malloc_zero(sizeof(*dir_port_cfg));
+    dir_port_cfg->type = CONN_TYPE_DIR_LISTENER;
+    dir_port_cfg->addr.family = AF_INET;
+    dir_port_cfg->port = dir_port;
+    smartlist_add(mocked_configured_ports, dir_port_cfg);
+  }
+}
+
+/* Clean up the data structures and unmock the functions needed for generating
+ * a fresh descriptor. */
+static void
+cleanup_mocks_for_fresh_descriptor(void)
+{
+  tor_free(get_options_mutable()->Nickname);
+
+  mocked_server_identitykey = NULL;
+  UNMOCK(get_server_identity_key);
+
+  crypto_pk_free(mocked_onionkey);
+  UNMOCK(get_onion_key);
+}
+
+/* Mock the data structures and functions needed for generating a fresh
+ * descriptor.
+ *
+ * Sets options->Nickname from r1->nickname.
+ * Mocks get_server_identity_key() with r1->identity_pkey.
+ *
+ * If rsa_onion_keypair is not NULL, it is used to mock get_onion_key().
+ * Otherwise, the public key in r1->onion_pkey is used to mock get_onion_key().
+ */
 static void
-test_dir_formats(void *arg)
+setup_mocks_for_fresh_descriptor(const routerinfo_t *r1,
+                                 crypto_pk_t *rsa_onion_keypair)
+{
+  cleanup_mocks_for_fresh_descriptor();
+
+  tor_assert(r1);
+
+  /* router_build_fresh_signed_extrainfo() requires options->Nickname */
+  get_options_mutable()->Nickname = tor_strdup(r1->nickname);
+
+  /* router_build_fresh_signed_extrainfo() requires get_server_identity_key().
+   * Use the same one as the call to router_dump_router_to_string() above.
+   */
+  mocked_server_identitykey = r1->identity_pkey;
+  MOCK(get_server_identity_key, mock_get_server_identity_key);
+
+  /* router_dump_and_sign_routerinfo_descriptor_body() requires
+   * get_onion_key(). Use the same one as r1.
+   */
+  if (rsa_onion_keypair) {
+    mocked_onionkey = crypto_pk_dup_key(rsa_onion_keypair);
+  } else {
+    mocked_onionkey = router_get_rsa_onion_pkey(r1->onion_pkey,
+                                                r1->onion_pkey_len);
+  }
+  MOCK(get_onion_key, mock_get_onion_key);
+}
+
+/* Set options based on arg.
+ *
+ * b: BridgeRelay 1
+ * e: ExtraInfoStatistics 1
+ * s: sets all the individual statistics options to 1
+ *
+ * Always sets AssumeReachable to 1.
+ *
+ * Does not set ServerTransportPlugin, because it's parsed before use.
+ *
+ * Does not set BridgeRecordUsageByCountry, because the tests don't have access
+ * to a GeoIPFile or GeoIPv6File. */
+static void
+setup_dir_formats_options(const char *arg, or_options_t *options)
+{
+  /* Skip reachability checks for DirPort, ORPort, and tunnelled-dir-server */
+  options->AssumeReachable = 1;
+
+  if (strchr(arg, 'b')) {
+    options->BridgeRelay = 1;
+  }
+
+  if (strchr(arg, 'e')) {
+    options->ExtraInfoStatistics = 1;
+  }
+
+  if (strchr(arg, 's')) {
+    options->DirReqStatistics = 1;
+    options->HiddenServiceStatistics = 1;
+    options->EntryStatistics = 1;
+    options->CellStatistics = 1;
+    options->ExitPortStatistics = 1;
+    options->ConnDirectionStatistics = 1;
+    options->PaddingStatistics = 1;
+  }
+}
+
+/* Check that routerinfos r1 and rp1 are consistent.
+ * Only performs some basic checks.
+ */
+#define CHECK_ROUTERINFO_CONSISTENCY(r1, rp1) \
+STMT_BEGIN \
+  tt_assert(r1); \
+  tt_assert(rp1); \
+\
+  tt_int_op(rp1->addr,OP_EQ, r1->addr); \
+  tt_int_op(rp1->or_port,OP_EQ, r1->or_port); \
+  tt_int_op(rp1->dir_port,OP_EQ, r1->dir_port); \
+  tt_int_op(rp1->bandwidthrate,OP_EQ, r1->bandwidthrate); \
+  tt_int_op(rp1->bandwidthburst,OP_EQ, r1->bandwidthburst); \
+  tt_int_op(rp1->bandwidthcapacity,OP_EQ, r1->bandwidthcapacity); \
+  crypto_pk_t *rp1_onion_pkey = router_get_rsa_onion_pkey(rp1->onion_pkey, \
+                                                      rp1->onion_pkey_len); \
+  crypto_pk_t *r1_onion_pkey = router_get_rsa_onion_pkey(r1->onion_pkey, \
+                                                      r1->onion_pkey_len); \
+  tt_int_op(crypto_pk_cmp_keys(rp1_onion_pkey, r1_onion_pkey), OP_EQ, 0); \
+  crypto_pk_free(rp1_onion_pkey); \
+  crypto_pk_free(r1_onion_pkey); \
+  tt_int_op(crypto_pk_cmp_keys(rp1->identity_pkey, r1->identity_pkey), \
+            OP_EQ, 0); \
+  tt_int_op(rp1->supports_tunnelled_dir_requests, OP_EQ, \
+            r1->supports_tunnelled_dir_requests); \
+STMT_END
+
+/* Check that routerinfo r1 and extrainfo e1 are consistent.
+ * Only performs some basic checks.
+ */
+#define CHECK_EXTRAINFO_CONSISTENCY(r1, e1) \
+STMT_BEGIN \
+  tt_assert(r1); \
+  tt_assert(e1); \
+\
+  tt_str_op(e1->nickname, OP_EQ, r1->nickname); \
+STMT_END
+
+/** Run unit tests for router descriptor generation logic for a RSA-only
+ * router. Tor versions without ed25519 (0.2.6 and earlier) are no longer
+ * officially supported, but the authorities still accept their descriptors.
+ */
+static void
+test_dir_formats_rsa(void *arg)
 {
   char *buf = NULL;
-  char buf2[8192];
-  char platform[256];
-  char fingerprint[FINGERPRINT_LEN+1];
-  char *pk1_str = NULL, *pk2_str = NULL, *cp;
-  size_t pk1_str_len, pk2_str_len;
-  routerinfo_t *r1=NULL, *r2=NULL;
-  crypto_pk_t *pk1 = NULL, *pk2 = NULL;
-  routerinfo_t *rp1 = NULL, *rp2 = NULL;
-  addr_policy_t *ex1, *ex2;
-  routerlist_t *dir1 = NULL, *dir2 = NULL;
+  char *buf2 = NULL;
+  char *cp = NULL;
+
   uint8_t *rsa_cc = NULL;
-  or_options_t *options = get_options_mutable();
-  const addr_policy_t *p;
-  time_t now = time(NULL);
-  port_cfg_t orport, dirport;
-  char cert_buf[256];
 
-  (void)arg;
-  pk1 = pk_generate(0);
-  pk2 = pk_generate(1);
+  routerinfo_t *r1 = NULL;
+  extrainfo_t *e1 = NULL;
+  routerinfo_t *rp1 = NULL;
+  extrainfo_t *ep1 = NULL;
 
-  tt_assert(pk1 && pk2);
+  smartlist_t *chunks = NULL;
+  const char *msg = NULL;
+  int rv = -1;
+
+  or_options_t *options = get_options_mutable();
+  setup_dir_formats_options((const char *)arg, options);
 
   hibernate_set_state_for_testing_(HIBERNATE_STATE_LIVE);
 
-  get_platform_str(platform, sizeof(platform));
-  r1 = tor_malloc_zero(sizeof(routerinfo_t));
-  r1->addr = 0xc0a80001u; /* 192.168.0.1 */
-  r1->cache_info.published_on = 0;
-  r1->or_port = 9000;
-  r1->dir_port = 9003;
-  r1->supports_tunnelled_dir_requests = 1;
-  tor_addr_parse(&r1->ipv6_addr, "1:2:3:4::");
-  r1->ipv6_orport = 9999;
-  router_set_rsa_onion_pkey(pk1, &r1->onion_pkey, &r1->onion_pkey_len);
-  /* Fake just enough of an ntor key to get by */
+  /* r1 is a minimal, RSA-only descriptor, with DirPort and IPv6 */
+  r1 = basic_routerinfo_new("Magri", 0xc0a80001u /* 192.168.0.1 */,
+                            9000, 9003,
+                            1000, 5000, 10000,
+                            0,
+                            NULL);
+
+ /* Fake just enough of an ntor key to get by */
   curve25519_keypair_t r1_onion_keypair;
   curve25519_keypair_generate(&r1_onion_keypair, 0);
   r1->onion_curve25519_pkey = tor_memdup(&r1_onion_keypair.pubkey,
                                          sizeof(curve25519_public_key_t));
-  r1->identity_pkey = crypto_pk_dup_key(pk2);
-  r1->bandwidthrate = 1000;
-  r1->bandwidthburst = 5000;
-  r1->bandwidthcapacity = 10000;
+
+  /* Now add IPv6 */
+  tor_addr_parse(&r1->ipv6_addr, "1:2:3:4::");
+  r1->ipv6_orport = 9999;
+
   r1->exit_policy = NULL;
-  r1->nickname = tor_strdup("Magri");
-  r1->platform = tor_strdup(platform);
 
-  ex1 = tor_malloc_zero(sizeof(addr_policy_t));
-  ex2 = tor_malloc_zero(sizeof(addr_policy_t));
-  ex1->policy_type = ADDR_POLICY_ACCEPT;
-  tor_addr_from_ipv4h(&ex1->addr, 0);
-  ex1->maskbits = 0;
-  ex1->prt_min = ex1->prt_max = 80;
-  ex2->policy_type = ADDR_POLICY_REJECT;
-  tor_addr_from_ipv4h(&ex2->addr, 18<<24);
-  ex2->maskbits = 8;
-  ex2->prt_min = ex2->prt_max = 24;
-  r2 = tor_malloc_zero(sizeof(routerinfo_t));
-  r2->addr = 0x0a030201u; /* 10.3.2.1 */
+  /* XXXX+++ router_dump_to_string should really take this from ri. */
+  options->ContactInfo = tor_strdup("Magri White "
+                                    "<magri@elsewhere.example.com>");
+
+  setup_mock_configured_ports(r1->or_port, r1->dir_port);
+
+  buf = router_dump_router_to_string(r1, r1->identity_pkey, NULL, NULL, NULL);
+  tt_assert(buf);
+
+  tor_free(options->ContactInfo);
+  cleanup_mock_configured_ports();
+
+  /* Synthesise a router descriptor, without the signature */
+  chunks = smartlist_new();
+
+  smartlist_add(chunks, get_new_router_line(r1));
+  smartlist_add_strdup(chunks, "or-address [1:2:3:4::]:9999\n");
+
+  smartlist_add(chunks, get_new_platform_line());
+  smartlist_add(chunks, get_new_published_line(r1));
+  smartlist_add(chunks, get_new_fingerprint_line(r1));
+
+  smartlist_add(chunks, get_new_uptime_line(0));
+  smartlist_add(chunks, get_new_bandwidth_line(r1));
+
+  smartlist_add(chunks, get_new_onion_key_block(r1));
+  smartlist_add(chunks, get_new_signing_key_block(r1));
+
+  smartlist_add_strdup(chunks, "hidden-service-dir\n");
+
+  smartlist_add_strdup(chunks, "contact Magri White "
+                               "<magri@elsewhere.example.com>\n");
+
+  smartlist_add(chunks, get_new_bridge_distribution_request_line(options));
+  smartlist_add(chunks, get_new_ntor_onion_key_line(&r1_onion_keypair.pubkey));
+  smartlist_add_strdup(chunks, "reject *:*\n");
+  smartlist_add_strdup(chunks, "tunnelled-dir-server\n");
+
+  smartlist_add_strdup(chunks, "router-signature\n");
+
+  size_t len_out = 0;
+  buf2 = smartlist_join_strings(chunks, "", 0, &len_out);
+  SMARTLIST_FOREACH(chunks, char *, s, tor_free(s));
+  smartlist_free(chunks);
+
+  tt_assert(len_out > 0);
+
+  buf[strlen(buf2)] = '\0'; /* Don't compare the sig; it's never the same
+                             * twice */
+
+  tt_str_op(buf,OP_EQ, buf2);
+  tor_free(buf);
+
+  setup_mock_configured_ports(r1->or_port, r1->dir_port);
+
+  buf = router_dump_router_to_string(r1, r1->identity_pkey, NULL, NULL, NULL);
+  tt_assert(buf);
+
+  cleanup_mock_configured_ports();
+
+  /* Now, try to parse buf */
+  cp = buf;
+  rp1 = router_parse_entry_from_string((const char*)cp,NULL,1,0,NULL,NULL);
+
+  CHECK_ROUTERINFO_CONSISTENCY(r1, rp1);
+
+  tt_assert(rp1->policy_is_reject_star);
+
+  tor_free(buf);
+  routerinfo_free(rp1);
+
+  /* Test extrainfo creation.
+   * We avoid calling router_build_fresh_unsigned_routerinfo(), because it's
+   * too complex. Instead, we re-use the manually-created routerinfos.
+   */
+
+  /* Set up standard mocks and data */
+  setup_mocks_for_fresh_descriptor(r1, NULL);
+
+  /* router_build_fresh_signed_extrainfo() passes the result of
+   * get_master_signing_key_cert() directly to tor_cert_dup(), which fails on
+   * NULL. But we want a NULL ei->cache_info.signing_key_cert to test the
+   * non-ed key path.
+   */
+  MOCK(tor_cert_dup, mock_tor_cert_dup_null);
+
+  /* Fake just enough of an ORPort and DirPort to get by */
+  setup_mock_configured_ports(r1->or_port, r1->dir_port);
+
+  /* Test some of the low-level static functions. */
+  e1 = router_build_fresh_signed_extrainfo(r1);
+  tt_assert(e1);
+  router_update_routerinfo_from_extrainfo(r1, e1);
+  rv = router_dump_and_sign_routerinfo_descriptor_body(r1);
+  tt_assert(rv == 0);
+  msg = "";
+  rv = routerinfo_incompatible_with_extrainfo(r1->identity_pkey, e1,
+                                              &r1->cache_info, &msg);
+  /* If they are incompatible, fail and show the msg string */
+  tt_str_op(msg, OP_EQ, "");
+  tt_assert(rv == 0);
+
+  /* Now cleanup */
+  cleanup_mocks_for_fresh_descriptor();
+
+  UNMOCK(tor_cert_dup);
+
+  cleanup_mock_configured_ports();
+
+  CHECK_EXTRAINFO_CONSISTENCY(r1, e1);
+
+  /* Test that the signed ri is parseable */
+  tt_assert(r1->cache_info.signed_descriptor_body);
+  cp = r1->cache_info.signed_descriptor_body;
+  rp1 = router_parse_entry_from_string((const char*)cp,NULL,1,0,NULL,NULL);
+
+  CHECK_ROUTERINFO_CONSISTENCY(r1, rp1);
+
+  tt_assert(rp1->policy_is_reject_star);
+
+  routerinfo_free(rp1);
+
+  /* Test that the signed ei is parseable */
+  tt_assert(e1->cache_info.signed_descriptor_body);
+  cp = e1->cache_info.signed_descriptor_body;
+  ep1 = extrainfo_parse_entry_from_string((const char*)cp,NULL,1,NULL,NULL);
+
+  CHECK_EXTRAINFO_CONSISTENCY(r1, ep1);
+
+  /* In future tests, we could check the actual extrainfo statistics. */
+
+  extrainfo_free(ep1);
+
+ done:
+  dirserv_free_fingerprint_list();
+
+  tor_free(options->ContactInfo);
+  tor_free(options->Nickname);
+
+  cleanup_mock_configured_ports();
+  cleanup_mocks_for_fresh_descriptor();
+
+  if (chunks) {
+    SMARTLIST_FOREACH(chunks, char *, s, tor_free(s));
+    smartlist_free(chunks);
+  }
+
+  routerinfo_free(r1);
+  routerinfo_free(rp1);
+
+  extrainfo_free(e1);
+  extrainfo_free(ep1);
+
+  tor_free(rsa_cc);
+
+  tor_free(buf);
+  tor_free(buf2);
+}
+
+/* Check that the exit policy in rp2 is as expected. */
+#define CHECK_PARSED_EXIT_POLICY(rp2) \
+STMT_BEGIN \
+  tt_int_op(smartlist_len(rp2->exit_policy),OP_EQ, 2); \
+ \
+  p = smartlist_get(rp2->exit_policy, 0); \
+  tt_int_op(p->policy_type,OP_EQ, ADDR_POLICY_ACCEPT); \
+  tt_assert(tor_addr_is_null(&p->addr)); \
+  tt_int_op(p->maskbits,OP_EQ, 0); \
+  tt_int_op(p->prt_min,OP_EQ, 80); \
+  tt_int_op(p->prt_max,OP_EQ, 80); \
+ \
+  p = smartlist_get(rp2->exit_policy, 1); \
+  tt_int_op(p->policy_type,OP_EQ, ADDR_POLICY_REJECT); \
+  tt_assert(tor_addr_eq(&p->addr, &ex2->addr)); \
+  tt_int_op(p->maskbits,OP_EQ, 8); \
+  tt_int_op(p->prt_min,OP_EQ, 24); \
+  tt_int_op(p->prt_max,OP_EQ, 24); \
+STMT_END
+
+/** Run unit tests for router descriptor generation logic for a RSA + ed25519
+ * router.
+ */
+static void
+test_dir_formats_rsa_ed25519(void *arg)
+{
+  char *buf = NULL;
+  char *buf2 = NULL;
+  char *cp = NULL;
+
+  crypto_pk_t *r2_onion_pkey = NULL;
+  char cert_buf[256];
+  uint8_t *rsa_cc = NULL;
+  time_t now = time(NULL);
+
+  routerinfo_t *r2 = NULL;
+  extrainfo_t *e2 = NULL;
+  routerinfo_t *r2_out = NULL;
+  routerinfo_t *rp2 = NULL;
+  extrainfo_t *ep2 = NULL;
+  addr_policy_t *ex1, *ex2;
+  const addr_policy_t *p;
+
+  smartlist_t *chunks = NULL;
+  int rv = -1;
+
+  or_options_t *options = get_options_mutable();
+  setup_dir_formats_options((const char *)arg, options);
+
+  hibernate_set_state_for_testing_(HIBERNATE_STATE_LIVE);
+
+  /* r2 is a RSA + ed25519 descriptor, with an exit policy, but no DirPort or
+   * IPv6 */
+  r2 = basic_routerinfo_new("Fred", 0x0a030201u /* 10.3.2.1 */,
+                            9005, 0,
+                            3000, 3000, 3000,
+                            5,
+                            &r2_onion_pkey);
+
+  /* Fake just enough of an ntor key to get by */
+  curve25519_keypair_t r2_onion_keypair;
+  curve25519_keypair_generate(&r2_onion_keypair, 0);
+  r2->onion_curve25519_pkey = tor_memdup(&r2_onion_keypair.pubkey,
+                                         sizeof(curve25519_public_key_t));
+
+  /* Now add relay ed25519 keys
+   * We can't use init_mock_ed_keys() here, because the keys are seeded */
   ed25519_keypair_t kp1, kp2;
   ed25519_secret_key_from_seed(&kp1.seckey,
                           (const uint8_t*)"YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY");
@@ -248,157 +950,78 @@ test_dir_formats(void *arg)
                                          &kp2.pubkey,
                                          now, 86400,
                                          CERT_FLAG_INCLUDE_SIGNING_KEY);
-  r2->platform = tor_strdup(platform);
-  r2->cache_info.published_on = 5;
-  r2->or_port = 9005;
-  r2->dir_port = 0;
-  r2->supports_tunnelled_dir_requests = 1;
-  router_set_rsa_onion_pkey(pk2, &r2->onion_pkey, &r2->onion_pkey_len);
-  curve25519_keypair_t r2_onion_keypair;
-  curve25519_keypair_generate(&r2_onion_keypair, 0);
-  r2->onion_curve25519_pkey = tor_memdup(&r2_onion_keypair.pubkey,
-                                         sizeof(curve25519_public_key_t));
-  r2->identity_pkey = crypto_pk_dup_key(pk1);
-  r2->bandwidthrate = r2->bandwidthburst = r2->bandwidthcapacity = 3000;
+
+  /* Now add an exit policy */
+  ex1 = tor_malloc_zero(sizeof(addr_policy_t));
+  ex2 = tor_malloc_zero(sizeof(addr_policy_t));
+  ex1->policy_type = ADDR_POLICY_ACCEPT;
+  tor_addr_from_ipv4h(&ex1->addr, 0);
+  ex1->maskbits = 0;
+  ex1->prt_min = ex1->prt_max = 80;
+  ex2->policy_type = ADDR_POLICY_REJECT;
+  tor_addr_from_ipv4h(&ex2->addr, 18<<24);
+  ex2->maskbits = 8;
+  ex2->prt_min = ex2->prt_max = 24;
+
   r2->exit_policy = smartlist_new();
   smartlist_add(r2->exit_policy, ex1);
   smartlist_add(r2->exit_policy, ex2);
-  r2->nickname = tor_strdup("Fred");
-
-  tt_assert(!crypto_pk_write_public_key_to_string(pk1, &pk1_str,
-                                                    &pk1_str_len));
-  tt_assert(!crypto_pk_write_public_key_to_string(pk2 , &pk2_str,
-                                                    &pk2_str_len));
-
-  /* XXXX+++ router_dump_to_string should really take this from ri.*/
-  options->ContactInfo = tor_strdup("Magri White "
-                                    "<magri@elsewhere.example.com>");
-  /* Skip reachability checks for DirPort and tunnelled-dir-server */
-  options->AssumeReachable = 1;
-
-  /* Fake just enough of an ORPort and DirPort to get by */
-  MOCK(get_configured_ports, mock_get_configured_ports);
-  mocked_configured_ports = smartlist_new();
-
-  memset(&orport, 0, sizeof(orport));
-  orport.type = CONN_TYPE_OR_LISTENER;
-  orport.addr.family = AF_INET;
-  orport.port = 9000;
-  smartlist_add(mocked_configured_ports, &orport);
-
-  memset(&dirport, 0, sizeof(dirport));
-  dirport.type = CONN_TYPE_DIR_LISTENER;
-  dirport.addr.family = AF_INET;
-  dirport.port = 9003;
-  smartlist_add(mocked_configured_ports, &dirport);
 
-  buf = router_dump_router_to_string(r1, pk2, NULL, NULL, NULL);
-
-  UNMOCK(get_configured_ports);
-  smartlist_free(mocked_configured_ports);
-  mocked_configured_ports = NULL;
+  /* Fake just enough of an ORPort to get by */
+  setup_mock_configured_ports(r2->or_port, 0);
 
-  tor_free(options->ContactInfo);
+  buf = router_dump_router_to_string(r2,
+                                     r2->identity_pkey, r2_onion_pkey,
+                                     &r2_onion_keypair, &kp2);
   tt_assert(buf);
 
-  strlcpy(buf2, "router Magri 192.168.0.1 9000 0 9003\n"
-          "or-address [1:2:3:4::]:9999\n"
-          "platform Tor "VERSION" on ", sizeof(buf2));
-  strlcat(buf2, get_uname(), sizeof(buf2));
-  strlcat(buf2, "\n"
-          "published 1970-01-01 00:00:00\n"
-          "fingerprint ", sizeof(buf2));
-  tt_assert(!crypto_pk_get_fingerprint(pk2, fingerprint, 1));
-  strlcat(buf2, fingerprint, sizeof(buf2));
-  strlcat(buf2, "\nuptime 0\n"
-  /* XXX the "0" above is hard-coded, but even if we made it reflect
-   * uptime, that still wouldn't make it right, because the two
-   * descriptors might be made on different seconds... hm. */
-         "bandwidth 1000 5000 10000\n"
-          "onion-key\n", sizeof(buf2));
-  strlcat(buf2, pk1_str, sizeof(buf2));
-  strlcat(buf2, "signing-key\n", sizeof(buf2));
-  strlcat(buf2, pk2_str, sizeof(buf2));
-  strlcat(buf2, "hidden-service-dir\n", sizeof(buf2));
-  strlcat(buf2, "contact Magri White <magri@elsewhere.example.com>\n",
-          sizeof(buf2));
-  strlcat(buf2, "ntor-onion-key ", sizeof(buf2));
-  base64_encode(cert_buf, sizeof(cert_buf),
-                (const char*)r1_onion_keypair.pubkey.public_key, 32,
-                BASE64_ENCODE_MULTILINE);
-  strlcat(buf2, cert_buf, sizeof(buf2));
-  strlcat(buf2, "reject *:*\n", sizeof(buf2));
-  strlcat(buf2, "tunnelled-dir-server\nrouter-signature\n", sizeof(buf2));
-  buf[strlen(buf2)] = '\0'; /* Don't compare the sig; it's never the same
-                             * twice */
+  cleanup_mock_configured_ports();
 
-  tt_str_op(buf,OP_EQ, buf2);
-  tor_free(buf);
+  chunks = smartlist_new();
 
-  buf = router_dump_router_to_string(r1, pk2, NULL, NULL, NULL);
-  tt_assert(buf);
-  cp = buf;
-  rp1 = router_parse_entry_from_string((const char*)cp,NULL,1,0,NULL,NULL);
-  tt_assert(rp1);
-  tt_int_op(rp1->addr,OP_EQ, r1->addr);
-  tt_int_op(rp1->or_port,OP_EQ, r1->or_port);
-  tt_int_op(rp1->dir_port,OP_EQ, r1->dir_port);
-  tt_int_op(rp1->bandwidthrate,OP_EQ, r1->bandwidthrate);
-  tt_int_op(rp1->bandwidthburst,OP_EQ, r1->bandwidthburst);
-  tt_int_op(rp1->bandwidthcapacity,OP_EQ, r1->bandwidthcapacity);
-  crypto_pk_t *onion_pkey = router_get_rsa_onion_pkey(rp1->onion_pkey,
-                                                      rp1->onion_pkey_len);
-  tt_int_op(crypto_pk_cmp_keys(onion_pkey, pk1), OP_EQ, 0);
-  crypto_pk_free(onion_pkey);
-  tt_int_op(crypto_pk_cmp_keys(rp1->identity_pkey, pk2), OP_EQ, 0);
-  tt_assert(rp1->supports_tunnelled_dir_requests);
-  //tt_assert(rp1->exit_policy == NULL);
-  tor_free(buf);
+  /* Synthesise a router descriptor, without the signatures */
+  smartlist_add(chunks, get_new_router_line(r2));
 
-  strlcpy(buf2,
-          "router Fred 10.3.2.1 9005 0 0\n"
-          "identity-ed25519\n"
-          "-----BEGIN ED25519 CERT-----\n", sizeof(buf2));
+  smartlist_add_strdup(chunks,
+                       "identity-ed25519\n"
+                       "-----BEGIN ED25519 CERT-----\n");
   base64_encode(cert_buf, sizeof(cert_buf),
                 (const char*)r2->cache_info.signing_key_cert->encoded,
                 r2->cache_info.signing_key_cert->encoded_len,
                 BASE64_ENCODE_MULTILINE);
-  strlcat(buf2, cert_buf, sizeof(buf2));
-  strlcat(buf2, "-----END ED25519 CERT-----\n", sizeof(buf2));
-  strlcat(buf2, "master-key-ed25519 ", sizeof(buf2));
+  smartlist_add_strdup(chunks, cert_buf);
+  smartlist_add_strdup(chunks, "-----END ED25519 CERT-----\n");
+
+  smartlist_add_strdup(chunks, "master-key-ed25519 ");
   {
     char k[ED25519_BASE64_LEN+1];
-    tt_int_op(ed25519_public_to_base64(k,
-                          &r2->cache_info.signing_key_cert->signing_key),
-              OP_GE, 0);
-    strlcat(buf2, k, sizeof(buf2));
-    strlcat(buf2, "\n", sizeof(buf2));
+    ed25519_public_to_base64(k, &r2->cache_info.signing_key_cert->signing_key);
+    smartlist_add_strdup(chunks, k);
+    smartlist_add_strdup(chunks, "\n");
   }
-  strlcat(buf2, "platform Tor "VERSION" on ", sizeof(buf2));
-  strlcat(buf2, get_uname(), sizeof(buf2));
-  strlcat(buf2, "\n"
-          "published 1970-01-01 00:00:05\n"
-          "fingerprint ", sizeof(buf2));
-  tt_assert(!crypto_pk_get_fingerprint(pk1, fingerprint, 1));
-  strlcat(buf2, fingerprint, sizeof(buf2));
-  strlcat(buf2, "\nuptime 0\n"
-          "bandwidth 3000 3000 3000\n", sizeof(buf2));
-  strlcat(buf2, "onion-key\n", sizeof(buf2));
-  strlcat(buf2, pk2_str, sizeof(buf2));
-  strlcat(buf2, "signing-key\n", sizeof(buf2));
-  strlcat(buf2, pk1_str, sizeof(buf2));
+
+  smartlist_add(chunks, get_new_platform_line());
+  smartlist_add(chunks, get_new_published_line(r2));
+  smartlist_add(chunks, get_new_fingerprint_line(r2));
+
+  smartlist_add(chunks, get_new_uptime_line(0));
+  smartlist_add(chunks, get_new_bandwidth_line(r2));
+
+  smartlist_add(chunks, get_new_onion_key_block(r2));
+  smartlist_add(chunks, get_new_signing_key_block(r2));
+
   int rsa_cc_len;
-  rsa_cc = make_tap_onion_key_crosscert(pk2,
+  rsa_cc = make_tap_onion_key_crosscert(r2_onion_pkey,
                                         &kp1.pubkey,
-                                        pk1,
+                                        r2->identity_pkey,
                                         &rsa_cc_len);
   tt_assert(rsa_cc);
   base64_encode(cert_buf, sizeof(cert_buf), (char*)rsa_cc, rsa_cc_len,
                 BASE64_ENCODE_MULTILINE);
-  strlcat(buf2, "onion-key-crosscert\n"
-          "-----BEGIN CROSSCERT-----\n", sizeof(buf2));
-  strlcat(buf2, cert_buf, sizeof(buf2));
-  strlcat(buf2, "-----END CROSSCERT-----\n", sizeof(buf2));
+  smartlist_add_strdup(chunks, "onion-key-crosscert\n"
+                       "-----BEGIN CROSSCERT-----\n");
+  smartlist_add_strdup(chunks, cert_buf);
+  smartlist_add_strdup(chunks, "-----END CROSSCERT-----\n");
   int ntor_cc_sign;
   {
     tor_cert_t *ntor_cc = NULL;
@@ -413,112 +1036,165 @@ test_dir_formats(void *arg)
                 BASE64_ENCODE_MULTILINE);
     tor_cert_free(ntor_cc);
   }
-  tor_snprintf(buf2+strlen(buf2), sizeof(buf2)-strlen(buf2),
+  smartlist_add_asprintf(chunks,
                "ntor-onion-key-crosscert %d\n"
                "-----BEGIN ED25519 CERT-----\n"
                "%s"
                "-----END ED25519 CERT-----\n", ntor_cc_sign, cert_buf);
 
-  strlcat(buf2, "hidden-service-dir\n", sizeof(buf2));
-  strlcat(buf2, "ntor-onion-key ", sizeof(buf2));
-  base64_encode(cert_buf, sizeof(cert_buf),
-                (const char*)r2_onion_keypair.pubkey.public_key, 32,
-                BASE64_ENCODE_MULTILINE);
-  strlcat(buf2, cert_buf, sizeof(buf2));
-  strlcat(buf2, "accept *:80\nreject 18.0.0.0/8:24\n", sizeof(buf2));
-  strlcat(buf2, "tunnelled-dir-server\n", sizeof(buf2));
-  strlcat(buf2, "router-sig-ed25519 ", sizeof(buf2));
+  smartlist_add_strdup(chunks, "hidden-service-dir\n");
 
-  /* Fake just enough of an ORPort to get by */
-  MOCK(get_configured_ports, mock_get_configured_ports);
-  mocked_configured_ports = smartlist_new();
+  smartlist_add(chunks, get_new_bridge_distribution_request_line(options));
+  smartlist_add(chunks, get_new_ntor_onion_key_line(&r2_onion_keypair.pubkey));
+  smartlist_add_strdup(chunks, "accept *:80\nreject 18.0.0.0/8:24\n");
+  smartlist_add_strdup(chunks, "tunnelled-dir-server\n");
 
-  memset(&orport, 0, sizeof(orport));
-  orport.type = CONN_TYPE_OR_LISTENER;
-  orport.addr.family = AF_INET;
-  orport.port = 9005;
-  smartlist_add(mocked_configured_ports, &orport);
+  smartlist_add_strdup(chunks, "router-sig-ed25519 ");
 
-  buf = router_dump_router_to_string(r2, pk1, pk2, &r2_onion_keypair, &kp2);
-  tt_assert(buf);
-  buf[strlen(buf2)] = '\0'; /* Don't compare the sig; it's never the same
+  size_t len_out = 0;
+  buf2 = smartlist_join_strings(chunks, "", 0, &len_out);
+  SMARTLIST_FOREACH(chunks, char *, s, tor_free(s));
+  smartlist_free(chunks);
+
+  tt_assert(len_out > 0);
+
+  buf[strlen(buf2)] = '\0'; /* Don't compare either sig; they're never the same
                              * twice */
 
   tt_str_op(buf, OP_EQ, buf2);
   tor_free(buf);
 
-  buf = router_dump_router_to_string(r2, pk1, NULL, NULL, NULL);
+  setup_mock_configured_ports(r2->or_port, 0);
 
-  UNMOCK(get_configured_ports);
-  smartlist_free(mocked_configured_ports);
-  mocked_configured_ports = NULL;
+  buf = router_dump_router_to_string(r2, r2->identity_pkey, NULL, NULL, NULL);
+  tt_assert(buf);
 
-  /* Reset for later */
+  cleanup_mock_configured_ports();
+
+  /* Now, try to parse buf */
   cp = buf;
   rp2 = router_parse_entry_from_string((const char*)cp,NULL,1,0,NULL,NULL);
-  tt_assert(rp2);
-  tt_int_op(rp2->addr,OP_EQ, r2->addr);
-  tt_int_op(rp2->or_port,OP_EQ, r2->or_port);
-  tt_int_op(rp2->dir_port,OP_EQ, r2->dir_port);
-  tt_int_op(rp2->bandwidthrate,OP_EQ, r2->bandwidthrate);
-  tt_int_op(rp2->bandwidthburst,OP_EQ, r2->bandwidthburst);
-  tt_int_op(rp2->bandwidthcapacity,OP_EQ, r2->bandwidthcapacity);
+
+  CHECK_ROUTERINFO_CONSISTENCY(r2, rp2);
+
   tt_mem_op(rp2->onion_curve25519_pkey->public_key,OP_EQ,
              r2->onion_curve25519_pkey->public_key,
              CURVE25519_PUBKEY_LEN);
-  onion_pkey = router_get_rsa_onion_pkey(rp2->onion_pkey,
-                                         rp2->onion_pkey_len);
-  tt_int_op(crypto_pk_cmp_keys(onion_pkey, pk2), OP_EQ, 0);
-  crypto_pk_free(onion_pkey);
-  tt_int_op(crypto_pk_cmp_keys(rp2->identity_pkey, pk1), OP_EQ, 0);
-  tt_assert(rp2->supports_tunnelled_dir_requests);
-
-  tt_int_op(smartlist_len(rp2->exit_policy),OP_EQ, 2);
-
-  p = smartlist_get(rp2->exit_policy, 0);
-  tt_int_op(p->policy_type,OP_EQ, ADDR_POLICY_ACCEPT);
-  tt_assert(tor_addr_is_null(&p->addr));
-  tt_int_op(p->maskbits,OP_EQ, 0);
-  tt_int_op(p->prt_min,OP_EQ, 80);
-  tt_int_op(p->prt_max,OP_EQ, 80);
-
-  p = smartlist_get(rp2->exit_policy, 1);
-  tt_int_op(p->policy_type,OP_EQ, ADDR_POLICY_REJECT);
-  tt_assert(tor_addr_eq(&p->addr, &ex2->addr));
-  tt_int_op(p->maskbits,OP_EQ, 8);
-  tt_int_op(p->prt_min,OP_EQ, 24);
-  tt_int_op(p->prt_max,OP_EQ, 24);
-
-#if 0
-  /* Okay, now for the directories. */
-  {
-    fingerprint_list = smartlist_new();
-    crypto_pk_get_fingerprint(pk2, buf, 1);
-    add_fingerprint_to_dir(buf, fingerprint_list, 0);
-    crypto_pk_get_fingerprint(pk1, buf, 1);
-    add_fingerprint_to_dir(buf, fingerprint_list, 0);
+
+  CHECK_PARSED_EXIT_POLICY(rp2);
+
+  tor_free(buf);
+  routerinfo_free(rp2);
+
+  /* Test extrainfo creation. */
+
+  /* Set up standard mocks and data */
+  setup_mocks_for_fresh_descriptor(r2, r2_onion_pkey);
+
+  /* router_build_fresh_descriptor() requires
+   * router_build_fresh_unsigned_routerinfo(), but the implementation is
+   * too complex. Instead, we re-use r2.
+   */
+  mocked_routerinfo = r2;
+  MOCK(router_build_fresh_unsigned_routerinfo,
+       mock_router_build_fresh_unsigned_routerinfo);
+
+  /* r2 uses ed25519, so we need to mock the ed key functions */
+  mocked_master_signing_key = &kp2;
+  MOCK(get_master_signing_keypair, mock_get_master_signing_keypair);
+
+  mocked_signing_key_cert = r2->cache_info.signing_key_cert;
+  MOCK(get_master_signing_key_cert, mock_get_master_signing_key_cert);
+
+  mocked_curve25519_onion_key = &r2_onion_keypair;
+  MOCK(get_current_curve25519_keypair, mock_get_current_curve25519_keypair);
+
+  /* Fake just enough of an ORPort to get by */
+  setup_mock_configured_ports(r2->or_port, 0);
+
+  /* Test the high-level interface. */
+  rv = router_build_fresh_descriptor(&r2_out, &e2);
+  if (rv < 0) {
+    /* router_build_fresh_descriptor() frees r2 on failure. */
+    r2 = NULL;
+    /* Get rid of an alias to rp2 */
+    r2_out = NULL;
   }
+  tt_assert(rv == 0);
+  tt_assert(r2_out);
+  tt_assert(e2);
+  /* Guaranteed by mock_router_build_fresh_unsigned_routerinfo() */
+  tt_ptr_op(r2_out, OP_EQ, r2);
+  /* Get rid of an alias to r2 */
+  r2_out = NULL;
+
+  /* Now cleanup */
+  cleanup_mocks_for_fresh_descriptor();
+
+  mocked_routerinfo = NULL;
+  UNMOCK(router_build_fresh_unsigned_routerinfo);
+  mocked_master_signing_key = NULL;
+  UNMOCK(get_master_signing_keypair);
+  mocked_signing_key_cert = NULL;
+  UNMOCK(get_master_signing_key_cert);
+  mocked_curve25519_onion_key = NULL;
+  UNMOCK(get_current_curve25519_keypair);
+
+  cleanup_mock_configured_ports();
+
+  CHECK_EXTRAINFO_CONSISTENCY(r2, e2);
+
+  /* Test that the signed ri is parseable */
+  tt_assert(r2->cache_info.signed_descriptor_body);
+  cp = r2->cache_info.signed_descriptor_body;
+  rp2 = router_parse_entry_from_string((const char*)cp,NULL,1,0,NULL,NULL);
 
-#endif /* 0 */
-  dirserv_free_fingerprint_list();
+  CHECK_ROUTERINFO_CONSISTENCY(r2, rp2);
+
+  tt_mem_op(rp2->onion_curve25519_pkey->public_key,OP_EQ,
+            r2->onion_curve25519_pkey->public_key,
+            CURVE25519_PUBKEY_LEN);
+
+  CHECK_PARSED_EXIT_POLICY(rp2);
+
+  routerinfo_free(rp2);
+
+  /* Test that the signed ei is parseable */
+  tt_assert(e2->cache_info.signed_descriptor_body);
+  cp = e2->cache_info.signed_descriptor_body;
+  ep2 = extrainfo_parse_entry_from_string((const char*)cp,NULL,1,NULL,NULL);
+
+  CHECK_EXTRAINFO_CONSISTENCY(r2, ep2);
+
+  /* In future tests, we could check the actual extrainfo statistics. */
+
+  extrainfo_free(ep2);
 
  done:
-  if (r1)
-    routerinfo_free(r1);
-  if (r2)
-    routerinfo_free(r2);
-  if (rp2)
-    routerinfo_free(rp2);
+  dirserv_free_fingerprint_list();
+
+  tor_free(options->Nickname);
+
+  cleanup_mock_configured_ports();
+  cleanup_mocks_for_fresh_descriptor();
+
+  if (chunks) {
+    SMARTLIST_FOREACH(chunks, char *, s, tor_free(s));
+    smartlist_free(chunks);
+  }
+
+  routerinfo_free(r2);
+  routerinfo_free(r2_out);
+  routerinfo_free(rp2);
+
+  extrainfo_free(e2);
+  extrainfo_free(ep2);
 
   tor_free(rsa_cc);
+  crypto_pk_free(r2_onion_pkey);
+
   tor_free(buf);
-  tor_free(pk1_str);
-  tor_free(pk2_str);
-  if (pk1) crypto_pk_free(pk1);
-  if (pk2) crypto_pk_free(pk2);
-  if (rp1) routerinfo_free(rp1);
-  tor_free(dir1); /* XXXX And more !*/
-  tor_free(dir2); /* And more !*/
+  tor_free(buf2);
 }
 
 #include "failing_routerdescs.inc"
@@ -6546,7 +7222,22 @@ test_dir_format_versions_list(void *arg)
 
 struct testcase_t dir_tests[] = {
   DIR_LEGACY(nicknames),
-  DIR_LEGACY(formats),
+  /* extrainfo without any stats */
+  DIR_ARG(formats_rsa, TT_FORK, ""),
+  DIR_ARG(formats_rsa_ed25519, TT_FORK, ""),
+  /* on a bridge */
+  DIR_ARG(formats_rsa, TT_FORK, "b"),
+  DIR_ARG(formats_rsa_ed25519, TT_FORK, "b"),
+  /* extrainfo with basic stats */
+  DIR_ARG(formats_rsa, TT_FORK, "e"),
+  DIR_ARG(formats_rsa_ed25519, TT_FORK, "e"),
+  DIR_ARG(formats_rsa, TT_FORK, "be"),
+  DIR_ARG(formats_rsa_ed25519, TT_FORK, "be"),
+  /* extrainfo with all stats */
+  DIR_ARG(formats_rsa, TT_FORK, "es"),
+  DIR_ARG(formats_rsa_ed25519, TT_FORK, "es"),
+  DIR_ARG(formats_rsa, TT_FORK, "bes"),
+  DIR_ARG(formats_rsa_ed25519, TT_FORK, "bes"),
   DIR(routerinfo_parsing, 0),
   DIR(extrainfo_parsing, 0),
   DIR(parse_router_list, TT_FORK),
diff --git a/src/test/test_dir_common.h b/src/test/test_dir_common.h
index d6c5241b1..619dc83eb 100644
--- a/src/test/test_dir_common.h
+++ b/src/test/test_dir_common.h
@@ -3,6 +3,9 @@
  * Copyright (c) 2007-2019, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+#ifndef TOR_TEST_DIR_COMMON_H
+#define TOR_TEST_DIR_COMMON_H
+
 #include "core/or/or.h"
 #include "feature/nodelist/networkstatus.h"
 
@@ -49,3 +52,4 @@ int dir_common_construct_vote_3(networkstatus_t **vote,
                         networkstatus_t **vote_out, int *n_vrs, time_t now,
                         int clear_rl);
 
+#endif /* !defined(TOR_TEST_DIR_COMMON_H) */
diff --git a/src/test/test_dispatch.c b/src/test/test_dispatch.c
new file mode 100644
index 000000000..d6fe7e781
--- /dev/null
+++ b/src/test/test_dispatch.c
@@ -0,0 +1,249 @@
+/* Copyright (c) 2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#define DISPATCH_PRIVATE
+
+#include "test/test.h"
+
+#include "lib/dispatch/dispatch.h"
+#include "lib/dispatch/dispatch_cfg.h"
+#include "lib/dispatch/dispatch_st.h"
+#include "lib/dispatch/msgtypes.h"
+
+#include "lib/log/escape.h"
+#include "lib/malloc/malloc.h"
+#include "lib/string/printf.h"
+
+#include <stdio.h>
+#include <string.h>
+
+static dispatch_t *dispatcher_in_use=NULL;
+
+/* Construct an empty dispatch_t. */
+static void
+test_dispatch_empty(void *arg)
+{
+  (void)arg;
+
+  dispatch_t *d=NULL;
+  dispatch_cfg_t *cfg=NULL;
+
+  cfg = dcfg_new();
+  d = dispatch_new(cfg);
+  tt_assert(d);
+
+ done:
+  dispatch_free(d);
+  dcfg_free(cfg);
+}
+
+static int total_recv1_simple = 0;
+static int total_recv2_simple = 0;
+
+static void
+simple_recv1(const msg_t *m)
+{
+  total_recv1_simple += m->aux_data__.u64;
+}
+
+static char *recv2_received = NULL;
+
+static void
+simple_recv2(const msg_t *m)
+{
+  tor_free(recv2_received);
+  recv2_received = dispatch_fmt_msg_data(dispatcher_in_use, m);
+
+  total_recv2_simple += m->aux_data__.u64*10;
+}
+
+/* Construct a dispatch_t with two messages, make sure that they both get
+ * delivered. */
+static void
+test_dispatch_simple(void *arg)
+{
+  (void)arg;
+
+  dispatch_t *d=NULL;
+  dispatch_cfg_t *cfg=NULL;
+  int r;
+
+  cfg = dcfg_new();
+  r = dcfg_msg_set_type(cfg,0,0);
+  r += dcfg_msg_set_chan(cfg,0,0);
+  r += dcfg_add_recv(cfg,0,1,simple_recv1);
+  r += dcfg_msg_set_type(cfg,1,0);
+  r += dcfg_msg_set_chan(cfg,1,0);
+  r += dcfg_add_recv(cfg,1,1,simple_recv2);
+  r += dcfg_add_recv(cfg,1,1,simple_recv2); /* second copy */
+  tt_int_op(r, OP_EQ, 0);
+
+  d = dispatch_new(cfg);
+  tt_assert(d);
+  dispatcher_in_use = d;
+
+  msg_aux_data_t data = {.u64 = 7};
+  r = dispatch_send(d, 99, 0, 0, 0, data);
+  tt_int_op(r, OP_EQ, 0);
+  tt_int_op(total_recv1_simple, OP_EQ, 0);
+
+  r = dispatch_flush(d, 0, INT_MAX);
+  tt_int_op(r, OP_EQ, 0);
+  tt_int_op(total_recv1_simple, OP_EQ, 7);
+  tt_int_op(total_recv2_simple, OP_EQ, 0);
+
+  total_recv1_simple = 0;
+  r = dispatch_send(d, 99, 0, 1, 0, data);
+  tt_int_op(r, OP_EQ, 0);
+  r = dispatch_flush(d, 0, INT_MAX);
+  tt_int_op(total_recv1_simple, OP_EQ, 0);
+  tt_int_op(total_recv2_simple, OP_EQ, 140);
+
+  tt_str_op(recv2_received, OP_EQ, "<>"); // no format function was set.
+
+ done:
+  dispatch_free(d);
+  dcfg_free(cfg);
+  tor_free(recv2_received);
+}
+
+/* Construct a dispatch_t with a message and no reciever; make sure that it
+ * gets dropped properly. */
+static void
+test_dispatch_no_recipient(void *arg)
+{
+  (void)arg;
+
+  dispatch_t *d=NULL;
+  dispatch_cfg_t *cfg=NULL;
+  int r;
+
+  cfg = dcfg_new();
+  r = dcfg_msg_set_type(cfg,0,0);
+  r += dcfg_msg_set_chan(cfg,0,0);
+  tt_int_op(r, OP_EQ, 0);
+
+  d = dispatch_new(cfg);
+  tt_assert(d);
+  dispatcher_in_use = d;
+
+  msg_aux_data_t data = { .u64 = 7};
+  r = dispatch_send(d, 99, 0, 0, 0, data);
+  tt_int_op(r, OP_EQ, 0);
+
+  r = dispatch_flush(d, 0, INT_MAX);
+  tt_int_op(r, OP_EQ, 0);
+
+ done:
+  dispatch_free(d);
+  dcfg_free(cfg);
+}
+
+struct coord { int x; int y; };
+static void
+free_coord(msg_aux_data_t d)
+{
+  tor_free(d.ptr);
+}
+static char *
+fmt_coord(msg_aux_data_t d)
+{
+  char *v;
+  struct coord *c = d.ptr;
+  tor_asprintf(&v, "[%d, %d]", c->x, c->y);
+  return v;
+}
+static dispatch_typefns_t coord_fns = {
+  .fmt_fn = fmt_coord,
+  .free_fn = free_coord,
+};
+static void
+alert_run_immediate(dispatch_t *d, channel_id_t ch, void *arg)
+{
+  (void)arg;
+  dispatch_flush(d, ch, INT_MAX);
+}
+
+static char *received_data=NULL;
+
+static void
+recv_typed_data(const msg_t *m)
+{
+  tor_free(received_data);
+  received_data = dispatch_fmt_msg_data(dispatcher_in_use, m);
+}
+
+static void
+test_dispatch_with_types(void *arg)
+{
+  (void)arg;
+
+  dispatch_t *d=NULL;
+  dispatch_cfg_t *cfg=NULL;
+  int r;
+
+  cfg = dcfg_new();
+  r = dcfg_msg_set_type(cfg,5,3);
+  r += dcfg_msg_set_chan(cfg,5,2);
+  r += dcfg_add_recv(cfg,5,0,recv_typed_data);
+  r += dcfg_type_set_fns(cfg,3,&coord_fns);
+  tt_int_op(r, OP_EQ, 0);
+
+  d = dispatch_new(cfg);
+  tt_assert(d);
+  dispatcher_in_use = d;
+
+  /* Make this message get run immediately. */
+  r = dispatch_set_alert_fn(d, 2, alert_run_immediate, NULL);
+  tt_int_op(r, OP_EQ, 0);
+
+  struct coord *xy = tor_malloc(sizeof(*xy));
+  xy->x = 13;
+  xy->y = 37;
+  msg_aux_data_t data = {.ptr = xy};
+  r = dispatch_send(d, 99/*sender*/, 2/*channel*/, 5/*msg*/, 3/*type*/, data);
+  tt_int_op(r, OP_EQ, 0);
+  tt_str_op(received_data, OP_EQ, "[13, 37]");
+
+ done:
+  dispatch_free(d);
+  dcfg_free(cfg);
+  tor_free(received_data);
+  dispatcher_in_use = NULL;
+}
+
+static void
+test_dispatch_bad_type_setup(void *arg)
+{
+  (void)arg;
+  static dispatch_typefns_t fns;
+  dispatch_cfg_t *cfg = dcfg_new();
+
+  tt_int_op(0, OP_EQ, dcfg_type_set_fns(cfg, 7, &coord_fns));
+
+  fns = coord_fns;
+  fns.fmt_fn = NULL;
+  tt_int_op(-1, OP_EQ, dcfg_type_set_fns(cfg, 7, &fns));
+
+  fns = coord_fns;
+  fns.free_fn = NULL;
+  tt_int_op(-1, OP_EQ, dcfg_type_set_fns(cfg, 7, &fns));
+
+  fns = coord_fns;
+  tt_int_op(0, OP_EQ, dcfg_type_set_fns(cfg, 7, &fns));
+
+ done:
+  dcfg_free(cfg);
+}
+
+#define T(name)                                                 \
+  { #name, test_dispatch_ ## name, TT_FORK, NULL, NULL }
+
+struct testcase_t dispatch_tests[] = {
+  T(empty),
+  T(simple),
+  T(no_recipient),
+  T(with_types),
+  T(bad_type_setup),
+  END_OF_TESTCASES
+};
diff --git a/src/test/test_dns.c b/src/test/test_dns.c
index 231e6965f..51ff8729d 100644
--- a/src/test/test_dns.c
+++ b/src/test/test_dns.c
@@ -67,7 +67,7 @@ NS(test_main)(void *arg)
 
   tt_assert(tor_addr_family(nameserver_addr) == AF_INET);
   tt_assert(tor_addr_eq_ipv4h(nameserver_addr, 0x7f000001));
-#endif
+#endif /* !defined(_WIN32) */
 
   UNMOCK(get_options);
 
@@ -77,7 +77,7 @@ NS(test_main)(void *arg)
 }
 
 #undef NS_SUBMODULE
-#endif
+#endif /* defined(HAVE_EVDNS_BASE_GET_NAMESERVER_ADDR) */
 
 #define NS_SUBMODULE clip_ttl
 
diff --git a/src/test/test_dos.c b/src/test/test_dos.c
index 4756c5014..bda9908e6 100644
--- a/src/test/test_dos.c
+++ b/src/test/test_dos.c
@@ -411,7 +411,7 @@ test_dos_bucket_refill(void *arg)
   }
   tt_uint_op(current_circ_count, OP_EQ, 0);
   tt_uint_op(dos_stats->cc_stats.circuit_bucket, OP_EQ, current_circ_count);
-#endif
+#endif /* SIZEOF_TIME_T == 8 */
 
  done:
   tor_free(chan);
diff --git a/src/test/test_entrynodes.c b/src/test/test_entrynodes.c
index 729795b67..c43b21c67 100644
--- a/src/test/test_entrynodes.c
+++ b/src/test/test_entrynodes.c
@@ -67,7 +67,7 @@ static networkstatus_t *dummy_consensus = NULL;
 
 static smartlist_t *big_fake_net_nodes = NULL;
 
-static smartlist_t *
+static const smartlist_t *
 bfn_mock_nodelist_get_list(void)
 {
   return big_fake_net_nodes;
@@ -197,6 +197,7 @@ big_fake_network_setup(const struct testcase_t *testcase)
       n->md->exit_policy = parse_short_policy("accept 443");
     }
 
+    n->nodelist_idx = smartlist_len(big_fake_net_nodes);
     smartlist_add(big_fake_net_nodes, n);
   }
 
diff --git a/src/test/test_extorport.c b/src/test/test_extorport.c
index aeb71ec58..38aca9026 100644
--- a/src/test/test_extorport.c
+++ b/src/test/test_extorport.c
@@ -9,7 +9,7 @@
 #include "core/mainloop/connection.h"
 #include "core/or/connection_or.h"
 #include "app/config/config.h"
-#include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "feature/relay/ext_orport.h"
 #include "core/mainloop/mainloop.h"
@@ -18,6 +18,7 @@
 
 #include "test/test.h"
 #include "test/test_helpers.h"
+#include "test/rng_test_helpers.h"
 
 #ifdef HAVE_SYS_STAT_H
 #include <sys/stat.h>
@@ -176,7 +177,7 @@ test_ext_or_init_auth(void *arg)
   /* Shouldn't be initialized already, or our tests will be a bit
    * meaningless */
   ext_or_auth_cookie = tor_malloc_zero(32);
-  tt_assert(tor_mem_is_zero((char*)ext_or_auth_cookie, 32));
+  tt_assert(fast_mem_is_zero((char*)ext_or_auth_cookie, 32));
 
   /* Now make sure we use a temporary file */
   fn = get_fname("ext_cookie_file");
@@ -201,7 +202,7 @@ test_ext_or_init_auth(void *arg)
   tt_mem_op(cp,OP_EQ, "! Extended ORPort Auth Cookie !\x0a", 32);
   tt_mem_op(cp+32,OP_EQ, ext_or_auth_cookie, 32);
   memcpy(cookie0, ext_or_auth_cookie, 32);
-  tt_assert(!tor_mem_is_zero((char*)ext_or_auth_cookie, 32));
+  tt_assert(!fast_mem_is_zero((char*)ext_or_auth_cookie, 32));
 
   /* Operation should be idempotent. */
   tt_int_op(0, OP_EQ, init_ext_or_cookie_authentication(1));
@@ -303,16 +304,6 @@ test_ext_or_cookie_auth(void *arg)
 }
 
 static void
-crypto_rand_return_tse_str(char *to, size_t n)
-{
-  if (n != 32) {
-    TT_FAIL(("Asked for %d bytes, not 32", (int)n));
-    return;
-  }
-  memcpy(to, "te road There is always another ", 32);
-}
-
-static void
 test_ext_or_cookie_auth_testvec(void *arg)
 {
   char *reply=NULL, *client_hash=NULL;
@@ -326,7 +317,7 @@ test_ext_or_cookie_auth_testvec(void *arg)
   memcpy(ext_or_auth_cookie, "Gliding wrapt in a brown mantle," , 32);
   ext_or_auth_cookie_is_set = 1;
 
-  MOCK(crypto_rand, crypto_rand_return_tse_str);
+  testing_enable_prefilled_rng("te road There is always another ", 32);
 
   tt_int_op(0, OP_EQ,
             handle_client_auth_nonce(client_nonce, 32, &client_hash, &reply,
@@ -351,7 +342,7 @@ test_ext_or_cookie_auth_testvec(void *arg)
                  "33b3cd77ff79bd80c2074bbf438119a2");
 
  done:
-  UNMOCK(crypto_rand);
+  testing_disable_prefilled_rng();
   tor_free(reply);
   tor_free(client_hash);
   tor_free(mem_op_hex_tmp);
@@ -414,9 +405,9 @@ do_ext_or_handshake(or_connection_t *conn)
   CONTAINS("\x01\x00", 2);
   WRITE("\x01", 1);
   WRITE("But when I look ahead up the whi", 32);
-  MOCK(crypto_rand, crypto_rand_return_tse_str);
+  testing_enable_prefilled_rng("te road There is always another ", 32);
   tt_int_op(0, OP_EQ, connection_ext_or_process_inbuf(conn));
-  UNMOCK(crypto_rand);
+  testing_disable_prefilled_rng();
   tt_int_op(TO_CONN(conn)->state, OP_EQ,
             EXT_OR_CONN_STATE_AUTH_WAIT_CLIENT_HASH);
   CONTAINS("\xec\x80\xed\x6e\x54\x6d\x3b\x36\xfd\xfc\x22\xfe\x13\x15\x41\x6b"
@@ -481,9 +472,9 @@ test_ext_or_handshake(void *arg)
   tt_int_op(0, OP_EQ, connection_ext_or_process_inbuf(conn));
   /* send the rest of the nonce. */
   WRITE("ahead up the whi", 16);
-  MOCK(crypto_rand, crypto_rand_return_tse_str);
+  testing_enable_prefilled_rng("te road There is always another ", 32);
   tt_int_op(0, OP_EQ, connection_ext_or_process_inbuf(conn));
-  UNMOCK(crypto_rand);
+  testing_disable_prefilled_rng();
   /* We should get the right reply from the server. */
   CONTAINS("\xec\x80\xed\x6e\x54\x6d\x3b\x36\xfd\xfc\x22\xfe\x13\x15\x41\x6b"
            "\x02\x9f\x1a\xde\x76\x10\xd9\x10\x87\x8b\x62\xee\xb7\x40\x38\x21"
@@ -582,7 +573,7 @@ test_ext_or_handshake(void *arg)
 
  done:
   UNMOCK(connection_write_to_buf_impl_);
-  UNMOCK(crypto_rand);
+  testing_disable_prefilled_rng();
   if (conn)
     connection_free_minimal(TO_CONN(conn));
 #undef CONTAINS
diff --git a/src/test/test_helpers.c b/src/test/test_helpers.c
index 13de1e154..489c25776 100644
--- a/src/test/test_helpers.c
+++ b/src/test/test_helpers.c
@@ -78,7 +78,7 @@ helper_setup_fake_routerlist(void)
 {
   int retval;
   routerlist_t *our_routerlist = NULL;
-  smartlist_t *our_nodelist = NULL;
+  const smartlist_t *our_nodelist = NULL;
 
   /* Read the file that contains our test descriptors. */
 
diff --git a/src/test/test_hs.c b/src/test/test_hs.c
index a611b46ca..2b69aae54 100644
--- a/src/test/test_hs.c
+++ b/src/test/test_hs.c
@@ -6,7 +6,7 @@
  * \brief Unit tests for hidden service.
  **/
 
-#define CONTROL_PRIVATE
+#define CONTROL_EVENTS_PRIVATE
 #define CIRCUITBUILD_PRIVATE
 #define RENDCOMMON_PRIVATE
 #define RENDSERVICE_PRIVATE
@@ -15,6 +15,8 @@
 #include "core/or/or.h"
 #include "test/test.h"
 #include "feature/control/control.h"
+#include "feature/control/control_events.h"
+#include "feature/control/control_fmt.h"
 #include "app/config/config.h"
 #include "feature/hs/hs_common.h"
 #include "feature/rend/rendcommon.h"
@@ -321,6 +323,16 @@ test_hs_desc_event(void *arg)
   tt_str_op(received_msg,OP_EQ, expected_msg);
   tor_free(received_msg);
 
+  /* test HSDir rate limited */
+  rend_query.auth_type = REND_NO_AUTH;
+  control_event_hsv2_descriptor_failed(&rend_query.base_, NULL,
+                                     "QUERY_RATE_LIMITED");
+  expected_msg = "650 HS_DESC FAILED "STR_HS_ADDR" NO_AUTH " \
+                 "UNKNOWN REASON=QUERY_RATE_LIMITED\r\n";
+  tt_assert(received_msg);
+  tt_str_op(received_msg,OP_EQ, expected_msg);
+  tor_free(received_msg);
+
   /* Test invalid content with no HSDir fingerprint. */
   char *exp_msg;
   control_event_hs_descriptor_content(rend_query.onion_address,
@@ -436,7 +448,7 @@ test_hs_rend_data(void *arg)
   tt_int_op(client_v2->auth_type, OP_EQ, REND_BASIC_AUTH);
   tt_int_op(strlen(client_v2->onion_address), OP_EQ, 0);
   tt_mem_op(client_v2->desc_id_fetch, OP_EQ, desc_id, sizeof(desc_id));
-  tt_int_op(tor_mem_is_zero(client_v2->descriptor_cookie,
+  tt_int_op(fast_mem_is_zero(client_v2->descriptor_cookie,
                             sizeof(client_v2->descriptor_cookie)), OP_EQ, 1);
   tt_assert(client->hsdirs_fp);
   tt_int_op(smartlist_len(client->hsdirs_fp), OP_EQ, 0);
diff --git a/src/test/test_hs_cache.c b/src/test/test_hs_cache.c
index 918282911..d71f8b6b1 100644
--- a/src/test/test_hs_cache.c
+++ b/src/test/test_hs_cache.c
@@ -238,14 +238,13 @@ helper_fetch_desc_from_hsdir(const ed25519_public_key_t *blinded_key)
   {
     char hsdir_cache_key[ED25519_BASE64_LEN+1];
 
-    retval = ed25519_public_to_base64(hsdir_cache_key,
-                                      blinded_key);
-    tt_int_op(retval, OP_EQ, 0);
+    ed25519_public_to_base64(hsdir_cache_key, blinded_key);
     tor_asprintf(&hsdir_query_str, GET("/tor/hs/3/%s"), hsdir_cache_key);
   }
 
   /* Simulate an HTTP GET request to the HSDir */
   conn = dir_connection_new(AF_INET);
+  tt_assert(conn);
   tor_addr_from_ipv4h(&conn->base_.addr, 0x7f000001);
   TO_CONN(conn)->linked = 1;/* Pretend the conn is encrypted :) */
   retval = directory_handle_command_get(conn, hsdir_query_str,
@@ -487,7 +486,7 @@ test_client_cache(void *arg)
                                        NULL, &published_desc_str);
     tt_int_op(retval, OP_EQ, 0);
     memcpy(wanted_subcredential, published_desc->subcredential, DIGEST256_LEN);
-    tt_assert(!tor_mem_is_zero((char*)wanted_subcredential, DIGEST256_LEN));
+    tt_assert(!fast_mem_is_zero((char*)wanted_subcredential, DIGEST256_LEN));
   }
 
   /* Test handle_response_fetch_hsdesc_v3() */
diff --git a/src/test/test_hs_cell.c b/src/test/test_hs_cell.c
index f8af631c8..cdcbe23e6 100644
--- a/src/test/test_hs_cell.c
+++ b/src/test/test_hs_cell.c
@@ -39,7 +39,7 @@ test_gen_establish_intro_cell(void *arg)
      attempt to parse it. */
   {
     /* We only need the auth key pair here. */
-    hs_service_intro_point_t *ip = service_intro_point_new(NULL, 0, 0);
+    hs_service_intro_point_t *ip = service_intro_point_new(NULL);
     /* Auth key pair is generated in the constructor so we are all set for
      * using this IP object. */
     ret = hs_cell_build_establish_intro(circ_nonce, ip, buf);
@@ -107,7 +107,7 @@ test_gen_establish_intro_cell_bad(void *arg)
      ed25519_sign_prefixed() function and make it fail. */
   cell = trn_cell_establish_intro_new();
   tt_assert(cell);
-  ip = service_intro_point_new(NULL, 0, 0);
+  ip = service_intro_point_new(NULL);
   cell_len = hs_cell_build_establish_intro(circ_nonce, ip, NULL);
   service_intro_point_free(ip);
   expect_log_msg_containing("Unable to make signature for "
diff --git a/src/test/test_hs_client.c b/src/test/test_hs_client.c
index 2f2bb4558..0d25a98bb 100644
--- a/src/test/test_hs_client.c
+++ b/src/test/test_hs_client.c
@@ -14,6 +14,7 @@
 #define CIRCUITBUILD_PRIVATE
 #define CIRCUITLIST_PRIVATE
 #define CONNECTION_PRIVATE
+#define CRYPT_PATH_PRIVATE
 
 #include "test/test.h"
 #include "test/test_helpers.h"
@@ -44,6 +45,7 @@
 
 #include "core/or/cpath_build_state_st.h"
 #include "core/or/crypt_path_st.h"
+#include "core/or/crypt_path.h"
 #include "feature/dircommon/dir_connection_st.h"
 #include "core/or/entry_connection_st.h"
 #include "core/or/extend_info_st.h"
@@ -241,12 +243,14 @@ test_e2e_rend_circuit_setup_legacy(void *arg)
   tt_int_op(retval, OP_EQ, 1);
 
   /* Check the digest algo */
-  tt_int_op(crypto_digest_get_algorithm(or_circ->cpath->crypto.f_digest),
+  tt_int_op(
+         crypto_digest_get_algorithm(or_circ->cpath->pvt_crypto.f_digest),
             OP_EQ, DIGEST_SHA1);
-  tt_int_op(crypto_digest_get_algorithm(or_circ->cpath->crypto.b_digest),
+  tt_int_op(
+         crypto_digest_get_algorithm(or_circ->cpath->pvt_crypto.b_digest),
             OP_EQ, DIGEST_SHA1);
-  tt_assert(or_circ->cpath->crypto.f_crypto);
-  tt_assert(or_circ->cpath->crypto.b_crypto);
+  tt_assert(or_circ->cpath->pvt_crypto.f_crypto);
+  tt_assert(or_circ->cpath->pvt_crypto.b_crypto);
 
   /* Ensure that circ purpose was changed */
   tt_int_op(or_circ->base_.purpose, OP_EQ, CIRCUIT_PURPOSE_C_REND_JOINED);
@@ -311,12 +315,14 @@ test_e2e_rend_circuit_setup(void *arg)
   tt_int_op(retval, OP_EQ, 1);
 
   /* Check that the crypt path has prop224 algorithm parameters */
-  tt_int_op(crypto_digest_get_algorithm(or_circ->cpath->crypto.f_digest),
+  tt_int_op(
+         crypto_digest_get_algorithm(or_circ->cpath->pvt_crypto.f_digest),
             OP_EQ, DIGEST_SHA3_256);
-  tt_int_op(crypto_digest_get_algorithm(or_circ->cpath->crypto.b_digest),
+  tt_int_op(
+         crypto_digest_get_algorithm(or_circ->cpath->pvt_crypto.b_digest),
             OP_EQ, DIGEST_SHA3_256);
-  tt_assert(or_circ->cpath->crypto.f_crypto);
-  tt_assert(or_circ->cpath->crypto.b_crypto);
+  tt_assert(or_circ->cpath->pvt_crypto.f_crypto);
+  tt_assert(or_circ->cpath->pvt_crypto.b_crypto);
 
   /* Ensure that circ purpose was changed */
   tt_int_op(or_circ->base_.purpose, OP_EQ, CIRCUIT_PURPOSE_C_REND_JOINED);
@@ -395,7 +401,7 @@ test_client_pick_intro(void *arg)
     tt_assert(fetched_desc);
     tt_mem_op(fetched_desc->subcredential, OP_EQ, desc->subcredential,
               DIGEST256_LEN);
-    tt_assert(!tor_mem_is_zero((char*)fetched_desc->subcredential,
+    tt_assert(!fast_mem_is_zero((char*)fetched_desc->subcredential,
                                DIGEST256_LEN));
     tor_free(encoded);
   }
@@ -403,6 +409,9 @@ test_client_pick_intro(void *arg)
   /* 2) Mark all intro points except _the chosen one_ as failed. Then query the
    *   desc and get a random intro: check that we got _the chosen one_. */
   {
+    /* Tell hs_get_extend_info_from_lspecs() to skip the private address check.
+     */
+    get_options_mutable()->ExtendAllowPrivateAddresses = 1;
     /* Pick the chosen intro point and get its ei */
     hs_desc_intro_point_t *chosen_intro_point =
       smartlist_get(desc->encrypted_data.intro_points, 0);
@@ -430,7 +439,7 @@ test_client_pick_intro(void *arg)
     for (int i = 0; i < 64; ++i) {
       extend_info_t *ip = client_get_random_intro(&service_kp.pubkey);
       tor_assert(ip);
-      tt_assert(!tor_mem_is_zero((char*)ip->identity_digest, DIGEST_LEN));
+      tt_assert(!fast_mem_is_zero((char*)ip->identity_digest, DIGEST_LEN));
       tt_mem_op(ip->identity_digest, OP_EQ, chosen_intro_ei->identity_digest,
                 DIGEST_LEN);
       extend_info_free(ip);
@@ -476,6 +485,18 @@ test_client_pick_intro(void *arg)
     SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
                             hs_desc_intro_point_t *, ip) {
       extend_info_t *intro_ei = desc_intro_point_to_extend_info(ip);
+      /* desc_intro_point_to_extend_info() doesn't return IPv6 intro points
+       * yet, because we can't extend to them. See #24404, #24451, and #24181.
+       */
+      if (intro_ei == NULL) {
+        /* Pretend we're making a direct connection, and that we can use IPv6
+         */
+        get_options_mutable()->ClientUseIPv6 = 1;
+        intro_ei = hs_get_extend_info_from_lspecs(ip->link_specifiers,
+                                                  &ip->onion_key, 1);
+        tt_assert(tor_addr_family(&intro_ei->addr) == AF_INET6);
+      }
+      tt_assert(intro_ei);
       if (intro_ei) {
         const char *ptr;
         char ip_addr[TOR_ADDR_BUF_LEN];
diff --git a/src/test/test_hs_common.c b/src/test/test_hs_common.c
index eb7f3bfbb..abded6021 100644
--- a/src/test/test_hs_common.c
+++ b/src/test/test_hs_common.c
@@ -275,7 +275,7 @@ test_start_time_of_next_time_period(void *arg)
 static void
 cleanup_nodelist(void)
 {
-  smartlist_t *nodelist = nodelist_get_list();
+  const smartlist_t *nodelist = nodelist_get_list();
   SMARTLIST_FOREACH_BEGIN(nodelist, node_t *, node) {
     tor_free(node->md);
     node->md = NULL;
@@ -603,6 +603,10 @@ test_desc_reupload_logic(void *arg)
   SMARTLIST_FOREACH(ns->routerstatus_list,
                     routerstatus_t *, rs, routerstatus_free(rs));
   smartlist_clear(ns->routerstatus_list);
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   networkstatus_vote_free(ns);
   cleanup_nodelist();
   hs_free_all();
diff --git a/src/test/test_hs_control.c b/src/test/test_hs_control.c
index ba67712f1..7cedc987b 100644
--- a/src/test/test_hs_control.c
+++ b/src/test/test_hs_control.c
@@ -6,11 +6,13 @@
  * \brief Unit tests for hidden service control port event and command.
  **/
 
-#define CONTROL_PRIVATE
+#define CONTROL_EVENTS_PRIVATE
 
 #include "core/or/or.h"
 #include "test/test.h"
 #include "feature/control/control.h"
+#include "feature/control/control_events.h"
+#include "feature/control/control_fmt.h"
 #include "app/config/config.h"
 #include "feature/hs/hs_common.h"
 #include "feature/hs/hs_control.h"
@@ -105,8 +107,7 @@ test_hs_desc_event(void *arg)
   memset(&blinded_pk, 'B', sizeof(blinded_pk));
   memset(&hsdir_rs, 0, sizeof(hsdir_rs));
   memcpy(hsdir_rs.identity_digest, HSDIR_EXIST_ID, DIGEST_LEN);
-  ret = ed25519_public_to_base64(base64_blinded_pk, &blinded_pk);
-  tt_int_op(ret, OP_EQ, 0);
+  ed25519_public_to_base64(base64_blinded_pk, &blinded_pk);
   memcpy(&ident.identity_pk, &identity_kp.pubkey,
          sizeof(ed25519_public_key_t));
   memcpy(&ident.blinded_pk, &blinded_pk, sizeof(blinded_pk));
diff --git a/src/test/test_hs_descriptor.c b/src/test/test_hs_descriptor.c
index de584ed47..6fe5573c0 100644
--- a/src/test/test_hs_descriptor.c
+++ b/src/test/test_hs_descriptor.c
@@ -21,6 +21,7 @@
 #include "test/hs_test_helpers.h"
 #include "test/test_helpers.h"
 #include "test/log_test_helpers.h"
+#include "test/rng_test_helpers.h"
 
 #ifdef HAVE_CFLAG_WOVERLENGTH_STRINGS
 DISABLE_GCC_WARNING(overlength-strings)
@@ -30,13 +31,6 @@ DISABLE_GCC_WARNING(overlength-strings)
 #include "test_hs_descriptor.inc"
 ENABLE_GCC_WARNING(overlength-strings)
 
-/* Mock function to fill all bytes with 1 */
-static void
-mock_crypto_strongest_rand(uint8_t *out, size_t out_len)
-{
-  memset(out, 1, out_len);
-}
-
 /* Test certificate encoding put in a descriptor. */
 static void
 test_cert_encoding(void *arg)
@@ -132,7 +126,7 @@ test_descriptor_padding(void *arg)
     tt_assert(padded_plaintext);
     tor_free(plaintext);
     /* Make sure our padding has been zeroed. */
-    tt_int_op(tor_mem_is_zero((char *) padded_plaintext + plaintext_len,
+    tt_int_op(fast_mem_is_zero((char *) padded_plaintext + plaintext_len,
                               padded_len - plaintext_len), OP_EQ, 1);
     tor_free(padded_plaintext);
     /* Never never have a padded length smaller than the plaintext. */
@@ -149,7 +143,7 @@ test_descriptor_padding(void *arg)
     tt_assert(padded_plaintext);
     tor_free(plaintext);
     /* Make sure our padding has been zeroed. */
-    tt_int_op(tor_mem_is_zero((char *) padded_plaintext + plaintext_len,
+    tt_int_op(fast_mem_is_zero((char *) padded_plaintext + plaintext_len,
                               padded_len - plaintext_len), OP_EQ, 1);
     tor_free(padded_plaintext);
     /* Never never have a padded length smaller than the plaintext. */
@@ -166,7 +160,7 @@ test_descriptor_padding(void *arg)
     tt_assert(padded_plaintext);
     tor_free(plaintext);
     /* Make sure our padding has been zeroed. */
-    tt_int_op(tor_mem_is_zero((char *) padded_plaintext + plaintext_len,
+    tt_int_op(fast_mem_is_zero((char *) padded_plaintext + plaintext_len,
                               padded_len - plaintext_len), OP_EQ, 1);
     tor_free(padded_plaintext);
     /* Never never have a padded length smaller than the plaintext. */
@@ -179,115 +173,6 @@ test_descriptor_padding(void *arg)
 }
 
 static void
-test_link_specifier(void *arg)
-{
-  ssize_t ret;
-  hs_desc_link_specifier_t spec;
-  smartlist_t *link_specifiers = smartlist_new();
-  char buf[256];
-  char *b64 = NULL;
-  link_specifier_t *ls = NULL;
-
-  (void) arg;
-
-  /* Always this port. */
-  spec.u.ap.port = 42;
-  smartlist_add(link_specifiers, &spec);
-
-  /* Test IPv4 for starter. */
-  {
-    uint32_t ipv4;
-
-    spec.type = LS_IPV4;
-    ret = tor_addr_parse(&spec.u.ap.addr, "1.2.3.4");
-    tt_int_op(ret, OP_EQ, AF_INET);
-    b64 = encode_link_specifiers(link_specifiers);
-    tt_assert(b64);
-
-    /* Decode it and validate the format. */
-    ret = base64_decode(buf, sizeof(buf), b64, strlen(b64));
-    tt_int_op(ret, OP_GT, 0);
-    /* First byte is the number of link specifier. */
-    tt_int_op(get_uint8(buf), OP_EQ, 1);
-    ret = link_specifier_parse(&ls, (uint8_t *) buf + 1, ret - 1);
-    tt_int_op(ret, OP_EQ, 8);
-    /* Should be 2 bytes for port and 4 bytes for IPv4. */
-    tt_int_op(link_specifier_get_ls_len(ls), OP_EQ, 6);
-    ipv4 = link_specifier_get_un_ipv4_addr(ls);
-    tt_int_op(tor_addr_to_ipv4h(&spec.u.ap.addr), OP_EQ, ipv4);
-    tt_int_op(link_specifier_get_un_ipv4_port(ls), OP_EQ, spec.u.ap.port);
-
-    link_specifier_free(ls);
-    ls = NULL;
-    tor_free(b64);
-  }
-
-  /* Test IPv6. */
-  {
-    uint8_t ipv6[16];
-
-    spec.type = LS_IPV6;
-    ret = tor_addr_parse(&spec.u.ap.addr, "[1:2:3:4::]");
-    tt_int_op(ret, OP_EQ, AF_INET6);
-    b64 = encode_link_specifiers(link_specifiers);
-    tt_assert(b64);
-
-    /* Decode it and validate the format. */
-    ret = base64_decode(buf, sizeof(buf), b64, strlen(b64));
-    tt_int_op(ret, OP_GT, 0);
-    /* First byte is the number of link specifier. */
-    tt_int_op(get_uint8(buf), OP_EQ, 1);
-    ret = link_specifier_parse(&ls, (uint8_t *) buf + 1, ret - 1);
-    tt_int_op(ret, OP_EQ, 20);
-    /* Should be 2 bytes for port and 16 bytes for IPv6. */
-    tt_int_op(link_specifier_get_ls_len(ls), OP_EQ, 18);
-    for (unsigned int i = 0; i < sizeof(ipv6); i++) {
-      ipv6[i] = link_specifier_get_un_ipv6_addr(ls, i);
-    }
-    tt_mem_op(tor_addr_to_in6_addr8(&spec.u.ap.addr), OP_EQ, ipv6,
-              sizeof(ipv6));
-    tt_int_op(link_specifier_get_un_ipv6_port(ls), OP_EQ, spec.u.ap.port);
-
-    link_specifier_free(ls);
-    ls = NULL;
-    tor_free(b64);
-  }
-
-  /* Test legacy. */
-  {
-    uint8_t *id;
-
-    spec.type = LS_LEGACY_ID;
-    memset(spec.u.legacy_id, 'Y', sizeof(spec.u.legacy_id));
-    b64 = encode_link_specifiers(link_specifiers);
-    tt_assert(b64);
-
-    /* Decode it and validate the format. */
-    ret = base64_decode(buf, sizeof(buf), b64, strlen(b64));
-    tt_int_op(ret, OP_GT, 0);
-    /* First byte is the number of link specifier. */
-    tt_int_op(get_uint8(buf), OP_EQ, 1);
-    ret = link_specifier_parse(&ls, (uint8_t *) buf + 1, ret - 1);
-    /* 20 bytes digest + 1 byte type + 1 byte len. */
-    tt_int_op(ret, OP_EQ, 22);
-    tt_int_op(link_specifier_getlen_un_legacy_id(ls), OP_EQ, DIGEST_LEN);
-    /* Digest length is 20 bytes. */
-    tt_int_op(link_specifier_get_ls_len(ls), OP_EQ, DIGEST_LEN);
-    id = link_specifier_getarray_un_legacy_id(ls);
-    tt_mem_op(spec.u.legacy_id, OP_EQ, id, DIGEST_LEN);
-
-    link_specifier_free(ls);
-    ls = NULL;
-    tor_free(b64);
-  }
-
- done:
-  link_specifier_free(ls);
-  tor_free(b64);
-  smartlist_free(link_specifiers);
-}
-
-static void
 test_encode_descriptor(void *arg)
 {
   int ret;
@@ -848,8 +733,7 @@ test_desc_signature(void *arg)
   ret = ed25519_sign_prefixed(&sig, (const uint8_t *) data, strlen(data),
                               "Tor onion service descriptor sig v3", &kp);
   tt_int_op(ret, OP_EQ, 0);
-  ret = ed25519_signature_to_base64(sig_b64, &sig);
-  tt_int_op(ret, OP_EQ, 0);
+  ed25519_signature_to_base64(sig_b64, &sig);
   /* Build the descriptor that should be valid. */
   tor_asprintf(&desc, "%ssignature %s\n", data, sig_b64);
   ret = desc_sig_is_valid(sig_b64, &kp.pubkey, desc, strlen(desc));
@@ -909,7 +793,7 @@ test_build_authorized_client(void *arg)
                 client_pubkey_b16,
                 strlen(client_pubkey_b16));
 
-  MOCK(crypto_strongest_rand_, mock_crypto_strongest_rand);
+  testing_enable_prefilled_rng("\x01", 1);
 
   hs_desc_build_authorized_client(subcredential,
                                   &client_auth_pk, &auth_ephemeral_sk,
@@ -925,15 +809,13 @@ test_build_authorized_client(void *arg)
  done:
   tor_free(desc_client);
   tor_free(mem_op_hex_tmp);
-  UNMOCK(crypto_strongest_rand_);
+  testing_disable_prefilled_rng();
 }
 
 struct testcase_t hs_descriptor[] = {
   /* Encoding tests. */
   { "cert_encoding", test_cert_encoding, TT_FORK,
     NULL, NULL },
-  { "link_specifier", test_link_specifier, TT_FORK,
-    NULL, NULL },
   { "encode_descriptor", test_encode_descriptor, TT_FORK,
     NULL, NULL },
   { "descriptor_padding", test_descriptor_padding, TT_FORK,
diff --git a/src/test/test_hs_intropoint.c b/src/test/test_hs_intropoint.c
index 558fc32c5..732836fb5 100644
--- a/src/test/test_hs_intropoint.c
+++ b/src/test/test_hs_intropoint.c
@@ -50,7 +50,7 @@ new_establish_intro_cell(const char *circ_nonce,
 
   /* Auth key pair is generated in the constructor so we are all set for
    * using this IP object. */
-  ip = service_intro_point_new(NULL, 0, 0);
+  ip = service_intro_point_new(NULL);
   tt_assert(ip);
   cell_len = hs_cell_build_establish_intro(circ_nonce, ip, buf);
   tt_i64_op(cell_len, OP_GT, 0);
@@ -76,7 +76,7 @@ new_establish_intro_encoded_cell(const char *circ_nonce, uint8_t *cell_out)
 
   /* Auth key pair is generated in the constructor so we are all set for
    * using this IP object. */
-  ip = service_intro_point_new(NULL, 0, 0);
+  ip = service_intro_point_new(NULL);
   tt_assert(ip);
   cell_len = hs_cell_build_establish_intro(circ_nonce, ip, cell_out);
   tt_i64_op(cell_len, OP_GT, 0);
diff --git a/src/test/test_hs_service.c b/src/test/test_hs_service.c
index 43bf89438..a303f1041 100644
--- a/src/test/test_hs_service.c
+++ b/src/test/test_hs_service.c
@@ -21,6 +21,7 @@
 #define STATEFILE_PRIVATE
 #define TOR_CHANNEL_INTERNAL_
 #define HS_CLIENT_PRIVATE
+#define CRYPT_PATH_PRIVATE
 
 #include "test/test.h"
 #include "test/test_helpers.h"
@@ -60,6 +61,7 @@
 
 #include "core/or/cpath_build_state_st.h"
 #include "core/or/crypt_path_st.h"
+#include "core/or/crypt_path.h"
 #include "feature/nodelist/networkstatus_st.h"
 #include "feature/nodelist/node_st.h"
 #include "core/or/origin_circuit_st.h"
@@ -193,12 +195,14 @@ test_e2e_rend_circuit_setup(void *arg)
   tt_int_op(retval, OP_EQ, 1);
 
   /* Check the digest algo */
-  tt_int_op(crypto_digest_get_algorithm(or_circ->cpath->crypto.f_digest),
+  tt_int_op(
+         crypto_digest_get_algorithm(or_circ->cpath->pvt_crypto.f_digest),
             OP_EQ, DIGEST_SHA3_256);
-  tt_int_op(crypto_digest_get_algorithm(or_circ->cpath->crypto.b_digest),
+  tt_int_op(
+         crypto_digest_get_algorithm(or_circ->cpath->pvt_crypto.b_digest),
             OP_EQ, DIGEST_SHA3_256);
-  tt_assert(or_circ->cpath->crypto.f_crypto);
-  tt_assert(or_circ->cpath->crypto.b_crypto);
+  tt_assert(or_circ->cpath->pvt_crypto.f_crypto);
+  tt_assert(or_circ->cpath->pvt_crypto.b_crypto);
 
   /* Ensure that circ purpose was changed */
   tt_int_op(or_circ->base_.purpose, OP_EQ, CIRCUIT_PURPOSE_S_REND_JOINED);
@@ -328,17 +332,18 @@ helper_create_service_with_clients(int num_clients)
 static hs_service_intro_point_t *
 helper_create_service_ip(void)
 {
-  hs_desc_link_specifier_t *ls;
-  hs_service_intro_point_t *ip = service_intro_point_new(NULL, 0, 0);
+  link_specifier_t *ls;
+  hs_service_intro_point_t *ip = service_intro_point_new(NULL);
   tor_assert(ip);
   /* Add a first unused link specifier. */
-  ls = tor_malloc_zero(sizeof(*ls));
-  ls->type = LS_IPV4;
+  ls = link_specifier_new();
+  link_specifier_set_ls_type(ls, LS_IPV4);
   smartlist_add(ip->base.link_specifiers, ls);
   /* Add a second link specifier used by a test. */
-  ls = tor_malloc_zero(sizeof(*ls));
-  ls->type = LS_LEGACY_ID;
-  memset(ls->u.legacy_id, 'A', sizeof(ls->u.legacy_id));
+  ls = link_specifier_new();
+  link_specifier_set_ls_type(ls, LS_LEGACY_ID);
+  memset(link_specifier_getarray_un_legacy_id(ls), 'A',
+         link_specifier_getlen_un_legacy_id(ls));
   smartlist_add(ip->base.link_specifiers, ls);
 
   return ip;
@@ -392,11 +397,11 @@ test_load_keys(void *arg)
   tt_assert(s);
 
   /* Ok we have the service object. Validate few things. */
-  tt_assert(!tor_mem_is_zero(s->onion_address, sizeof(s->onion_address)));
+  tt_assert(!fast_mem_is_zero(s->onion_address, sizeof(s->onion_address)));
   tt_int_op(hs_address_is_valid(s->onion_address), OP_EQ, 1);
-  tt_assert(!tor_mem_is_zero((char *) s->keys.identity_sk.seckey,
+  tt_assert(!fast_mem_is_zero((char *) s->keys.identity_sk.seckey,
                              ED25519_SECKEY_LEN));
-  tt_assert(!tor_mem_is_zero((char *) s->keys.identity_pk.pubkey,
+  tt_assert(!fast_mem_is_zero((char *) s->keys.identity_pk.pubkey,
                              ED25519_PUBKEY_LEN));
   /* Check onion address from identity key. */
   hs_build_address(&s->keys.identity_pk, s->config.version, addr);
@@ -676,7 +681,7 @@ test_service_intro_point(void *arg)
     ip = helper_create_service_ip();
     tt_assert(ip);
     /* Make sure the authentication keypair is not zeroes. */
-    tt_int_op(tor_mem_is_zero((const char *) &ip->auth_key_kp,
+    tt_int_op(fast_mem_is_zero((const char *) &ip->auth_key_kp,
                               sizeof(ed25519_keypair_t)), OP_EQ, 0);
     /* The introduce2_max MUST be in that range. */
     tt_u64_op(ip->introduce2_max, OP_GE,
@@ -811,10 +816,11 @@ test_helper_functions(void *arg)
     const node_t *node = get_node_from_intro_point(ip);
     tt_ptr_op(node, OP_EQ, &mock_node);
     SMARTLIST_FOREACH_BEGIN(ip->base.link_specifiers,
-                            hs_desc_link_specifier_t *, ls) {
-      if (ls->type == LS_LEGACY_ID) {
+                            link_specifier_t *, ls) {
+      if (link_specifier_get_ls_type(ls) == LS_LEGACY_ID) {
         /* Change legacy id in link specifier which is not the mock node. */
-        memset(ls->u.legacy_id, 'B', sizeof(ls->u.legacy_id));
+        memset(link_specifier_getarray_un_legacy_id(ls), 'B',
+               link_specifier_getlen_un_legacy_id(ls));
       }
     } SMARTLIST_FOREACH_END(ls);
     node = get_node_from_intro_point(ip);
@@ -872,6 +878,10 @@ test_helper_functions(void *arg)
 
  done:
   /* This will free the service and all objects associated to it. */
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   hs_service_free_all();
   UNMOCK(node_get_by_id);
 }
@@ -881,7 +891,7 @@ static void
 test_intro_circuit_opened(void *arg)
 {
   int flags = CIRCLAUNCH_NEED_UPTIME | CIRCLAUNCH_IS_INTERNAL;
-  hs_service_t *service;
+  hs_service_t *service = NULL;
   origin_circuit_t *circ = NULL;
 
   (void) arg;
@@ -929,6 +939,10 @@ test_intro_circuit_opened(void *arg)
 
  done:
   circuit_free_(TO_CIRCUIT(circ));
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   hs_free_all();
   UNMOCK(circuit_mark_for_close_);
   UNMOCK(relay_send_command_from_edge_);
@@ -943,7 +957,7 @@ test_intro_established(void *arg)
   int flags = CIRCLAUNCH_NEED_UPTIME | CIRCLAUNCH_IS_INTERNAL;
   uint8_t payload[RELAY_PAYLOAD_SIZE] = {0};
   origin_circuit_t *circ = NULL;
-  hs_service_t *service;
+  hs_service_t *service = NULL;
   hs_service_intro_point_t *ip = NULL;
 
   (void) arg;
@@ -1004,6 +1018,10 @@ test_intro_established(void *arg)
  done:
   if (circ)
     circuit_free_(TO_CIRCUIT(circ));
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   hs_free_all();
   UNMOCK(circuit_mark_for_close_);
 }
@@ -1015,7 +1033,7 @@ test_rdv_circuit_opened(void *arg)
 {
   int flags = CIRCLAUNCH_NEED_UPTIME | CIRCLAUNCH_IS_INTERNAL;
   origin_circuit_t *circ = NULL;
-  hs_service_t *service;
+  hs_service_t *service = NULL;
 
   (void) arg;
 
@@ -1046,6 +1064,10 @@ test_rdv_circuit_opened(void *arg)
 
  done:
   circuit_free_(TO_CIRCUIT(circ));
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   hs_free_all();
   UNMOCK(circuit_mark_for_close_);
   UNMOCK(relay_send_command_from_edge_);
@@ -1133,6 +1155,10 @@ test_closing_intro_circs(void *arg)
     circuit_free_(TO_CIRCUIT(intro_circ));
   }
   /* Frees the service object. */
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   hs_free_all();
   UNMOCK(assert_circuit_ok);
 }
@@ -1145,7 +1171,7 @@ test_introduce2(void *arg)
   int flags = CIRCLAUNCH_NEED_UPTIME | CIRCLAUNCH_IS_INTERNAL;
   uint8_t payload[RELAY_PAYLOAD_SIZE] = {0};
   origin_circuit_t *circ = NULL;
-  hs_service_t *service;
+  hs_service_t *service = NULL;
   hs_service_intro_point_t *ip = NULL;
 
   (void) arg;
@@ -1212,6 +1238,10 @@ test_introduce2(void *arg)
   dummy_state = NULL;
   if (circ)
     circuit_free_(TO_CIRCUIT(circ));
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   hs_free_all();
   UNMOCK(circuit_mark_for_close_);
 }
@@ -1296,6 +1326,10 @@ test_service_event(void *arg)
  done:
   hs_circuitmap_remove_circuit(TO_CIRCUIT(circ));
   circuit_free_(TO_CIRCUIT(circ));
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   hs_free_all();
   UNMOCK(circuit_mark_for_close_);
 }
@@ -1306,7 +1340,7 @@ test_rotate_descriptors(void *arg)
 {
   int ret;
   time_t next_rotation_time, now;
-  hs_service_t *service;
+  hs_service_t *service = NULL;
   hs_service_descriptor_t *desc_next;
 
   (void) arg;
@@ -1398,6 +1432,10 @@ test_rotate_descriptors(void *arg)
   tt_assert(service->desc_next);
 
  done:
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   hs_free_all();
   UNMOCK(get_or_state);
   UNMOCK(circuit_mark_for_close_);
@@ -1411,7 +1449,7 @@ test_build_update_descriptors(void *arg)
 {
   int ret;
   node_t *node;
-  hs_service_t *service;
+  hs_service_t *service = NULL;
   hs_service_intro_point_t *ip_cur, *ip_next;
   routerinfo_t ri;
 
@@ -1560,9 +1598,9 @@ test_build_update_descriptors(void *arg)
   tt_int_op(smartlist_len(ip_cur->base.link_specifiers), OP_EQ, 3);
   /* Make sure we have a valid encryption keypair generated when we pick an
    * intro point in the update process. */
-  tt_assert(!tor_mem_is_zero((char *) ip_cur->enc_key_kp.seckey.secret_key,
+  tt_assert(!fast_mem_is_zero((char *) ip_cur->enc_key_kp.seckey.secret_key,
                              CURVE25519_SECKEY_LEN));
-  tt_assert(!tor_mem_is_zero((char *) ip_cur->enc_key_kp.pubkey.public_key,
+  tt_assert(!fast_mem_is_zero((char *) ip_cur->enc_key_kp.pubkey.public_key,
                              CURVE25519_PUBKEY_LEN));
   tt_u64_op(ip_cur->time_to_expire, OP_GE, now +
             INTRO_POINT_LIFETIME_MIN_SECONDS);
@@ -1628,6 +1666,10 @@ test_build_update_descriptors(void *arg)
   tt_u64_op(service->desc_next->next_upload_time, OP_EQ, 0);
 
  done:
+  if (service) {
+    remove_service(get_hs_service_map(), service);
+    hs_service_free(service);
+  }
   hs_free_all();
   nodelist_free_all();
 }
@@ -1882,9 +1924,9 @@ test_rendezvous1_parsing(void *arg)
   }
 
   /* Send out the RENDEZVOUS1 and make sure that our mock func worked */
-  tt_assert(tor_mem_is_zero(rend1_payload, 32));
+  tt_assert(fast_mem_is_zero(rend1_payload, 32));
   hs_circ_service_rp_has_opened(service, service_circ);
-  tt_assert(!tor_mem_is_zero(rend1_payload, 32));
+  tt_assert(!fast_mem_is_zero(rend1_payload, 32));
   tt_int_op(rend1_payload_len, OP_EQ, HS_LEGACY_RENDEZVOUS_CELL_SIZE);
 
   /******************************/
diff --git a/src/test/test_key_expiration.sh b/src/test/test_key_expiration.sh
index 347421060..54abb4a2f 100755
--- a/src/test/test_key_expiration.sh
+++ b/src/test/test_key_expiration.sh
@@ -6,14 +6,14 @@
 umask 077
 set -e
 
-if [ $# -eq 0 ] || [ ! -f ${1} ] || [ ! -x ${1} ]; then
+if [ $# -eq 0 ] || [ ! -f "${1}" ] || [ ! -x "${1}" ]; then
   if [ "$TESTING_TOR_BINARY" = "" ] ; then
     echo "Usage: ${0} PATH_TO_TOR [case-number]"
     exit 1
   fi
 fi
 
-UNAME_OS=`uname -s | cut -d_ -f1`
+UNAME_OS=$(uname -s | cut -d_ -f1)
 if test "$UNAME_OS" = 'CYGWIN' || \
    test "$UNAME_OS" = 'MSYS' || \
    test "$UNAME_OS" = 'MINGW'; then
@@ -47,11 +47,11 @@ dump() { xxd -p "$1" | tr -d '\n '; }
 die() { echo "$1" >&2 ; exit 5; }
 check_dir() { [ -d "$1" ] || die "$1 did not exist"; }
 check_file() { [ -e "$1" ] || die "$1 did not exist"; }
-check_no_file() { [ -e "$1" ] && die "$1 was not supposed to exist" || true; }
-check_files_eq() { cmp "$1" "$2" || die "$1 and $2 did not match: `dump $1` vs `dump $2`"; }
+check_no_file() { if [ -e "$1" ]; then die "$1 was not supposed to exist"; fi }
+check_files_eq() { cmp "$1" "$2" || die "$1 and $2 did not match: $(dump "$1") vs $(dump "$2")"; }
 check_keys_eq() { check_files_eq "${SRC}/keys/${1}" "${ME}/keys/${1}"; }
 
-DATA_DIR=`mktemp -d -t tor_key_expiration_tests.XXXXXX`
+DATA_DIR=$(mktemp -d -t tor_key_expiration_tests.XXXXXX)
 if [ -z "$DATA_DIR" ]; then
   echo "Failure: mktemp invocation returned empty string" >&2
   exit 3
@@ -60,10 +60,10 @@ if [ ! -d "$DATA_DIR" ]; then
   echo "Failure: mktemp invocation result doesn't point to directory" >&2
   exit 3
 fi
-trap "rm -rf '$DATA_DIR'" 0
+trap 'rm -rf "$DATA_DIR"' 0
 
 # Use an absolute path for this or Tor will complain
-DATA_DIR=`cd "${DATA_DIR}" && pwd`
+DATA_DIR=$(cd "${DATA_DIR}" && pwd)
 
 touch "${DATA_DIR}/empty_torrc"
 touch "${DATA_DIR}/empty_defaults_torrc"
diff --git a/src/test/test_keygen.sh b/src/test/test_keygen.sh
index 7afff271c..cbdfd1909 100755
--- a/src/test/test_keygen.sh
+++ b/src/test/test_keygen.sh
@@ -6,14 +6,14 @@
 umask 077
 set -e
 
-if [ $# -eq 0 ] || [ ! -f ${1} ] || [ ! -x ${1} ]; then
+if [ $# -eq 0 ] || [ ! -f "${1}" ] || [ ! -x "${1}" ]; then
   if [ "$TESTING_TOR_BINARY" = "" ] ; then
     echo "Usage: ${0} PATH_TO_TOR [case-number]"
     exit 1
   fi
 fi
 
-UNAME_OS=`uname -s | cut -d_ -f1`
+UNAME_OS=$(uname -s | cut -d_ -f1)
 if test "$UNAME_OS" = 'CYGWIN' || \
    test "$UNAME_OS" = 'MSYS' || \
    test "$UNAME_OS" = 'MINGW'; then
@@ -64,11 +64,11 @@ dump() { xxd -p "$1" | tr -d '\n '; }
 die() { echo "$1" >&2 ; exit 5; }
 check_dir() { [ -d "$1" ] || die "$1 did not exist"; }
 check_file() { [ -e "$1" ] || die "$1 did not exist"; }
-check_no_file() { [ -e "$1" ] && die "$1 was not supposed to exist" || true; }
-check_files_eq() { cmp "$1" "$2" || die "$1 and $2 did not match: `dump $1` vs `dump $2`"; }
+check_no_file() { if [ -e "$1" ]; then die "$1 was not supposed to exist"; fi }
+check_files_eq() { cmp "$1" "$2" || die "$1 and $2 did not match: $(dump "$1") vs $(dump "$2")"; }
 check_keys_eq() { check_files_eq "${SRC}/keys/${1}" "${ME}/keys/${1}"; }
 
-DATA_DIR=`mktemp -d -t tor_keygen_tests.XXXXXX`
+DATA_DIR=$(mktemp -d -t tor_keygen_tests.XXXXXX)
 if [ -z "$DATA_DIR" ]; then
   echo "Failure: mktemp invocation returned empty string" >&2
   exit 3
@@ -77,10 +77,10 @@ if [ ! -d "$DATA_DIR" ]; then
   echo "Failure: mktemp invocation result doesn't point to directory" >&2
   exit 3
 fi
-trap "rm -rf '$DATA_DIR'" 0
+trap 'rm -rf "$DATA_DIR"' 0
 
 # Use an absolute path for this or Tor will complain
-DATA_DIR=`cd "${DATA_DIR}" && pwd`
+DATA_DIR=$(cd "${DATA_DIR}" && pwd)
 
 touch "${DATA_DIR}/empty_torrc"
 touch "${DATA_DIR}/empty_defaults_torrc"
@@ -144,7 +144,9 @@ ME="${DATA_DIR}/case2a"
 SRC="${DATA_DIR}/orig"
 mkdir -p "${ME}/keys"
 cp "${SRC}/keys/ed25519_master_id_public_key" "${ME}/keys/"
-${TOR} --DataDirectory "${ME}" --list-fingerprint > "${ME}/stdout" && die "Somehow succeeded when missing secret key, certs: `cat ${ME}/stdout`" || true
+if ${TOR} --DataDirectory "${ME}" --list-fingerprint > "${ME}/stdout"; then
+  die "Somehow succeeded when missing secret key, certs: $(cat "${ME}/stdout")"
+fi
 check_files_eq "${SRC}/keys/ed25519_master_id_public_key" "${ME}/keys/ed25519_master_id_public_key"
 
 grep "We needed to load a secret key.*but couldn't find it" "${ME}/stdout" >/dev/null || die "Tor didn't declare that it was missing a secret key"
@@ -281,7 +283,9 @@ SRC="${DATA_DIR}/encrypted"
 mkdir -p "${ME}/keys"
 cp "${SRC}/keys/ed25519_master_id_secret_key_encrypted" "${ME}/keys/"
 cp "${SRC}/keys/ed25519_master_id_public_key" "${ME}/keys/"
-${TOR} --DataDirectory "${ME}" --list-fingerprint > "${ME}/stdout" && die "Tor started with encrypted secret key and no certs" || true
+if ${TOR} --DataDirectory "${ME}" --list-fingerprint > "${ME}/stdout"; then
+  die "Tor started with encrypted secret key and no certs"
+fi
 check_no_file "${ME}/keys/ed25519_signing_cert"
 check_no_file "${ME}/keys/ed25519_signing_secret_key"
 
@@ -370,7 +374,9 @@ mkdir -p "${ME}/keys"
 cp "${SRC}/keys/ed25519_master_id_public_key" "${ME}/keys/"
 cp "${OTHER}/keys/ed25519_master_id_secret_key" "${ME}/keys/"
 
-${TOR} --DataDirectory "${ME}" --list-fingerprint >"${ME}/stdout" && die "Successfully started with mismatched keys!?" || true
+if ${TOR} --DataDirectory "${ME}" --list-fingerprint >"${ME}/stdout"; then
+  die "Successfully started with mismatched keys!?"
+fi
 
 grep "public_key does not match.*secret_key" "${ME}/stdout" >/dev/null || die "Tor didn't declare that there was a key mismatch"
 
@@ -386,7 +392,9 @@ ME="${DATA_DIR}/case11a"
 
 mkdir -p "${ME}/keys"
 
-${TOR} --DataDirectory "${ME}" --passphrase-fd 1 > "${ME}/stdout" && die "Successfully started with passphrase-fd but no keygen?" || true
+if ${TOR} --DataDirectory "${ME}" --passphrase-fd 1 > "${ME}/stdout"; then
+  die "Successfully started with passphrase-fd but no keygen?"
+fi
 
 grep "passphrase-fd specified without --keygen" "${ME}/stdout" >/dev/null || die "Tor didn't declare that there was a problem with the arguments."
 
@@ -402,7 +410,9 @@ ME="${DATA_DIR}/case11b"
 
 mkdir -p "${ME}/keys"
 
-${TOR} --DataDirectory "${ME}" --no-passphrase > "${ME}/stdout" && die "Successfully started with no-passphrase but no keygen?" || true
+if ${TOR} --DataDirectory "${ME}" --no-passphrase > "${ME}/stdout"; then
+  die "Successfully started with no-passphrase but no keygen?"
+fi
 
 grep "no-passphrase specified without --keygen" "${ME}/stdout" >/dev/null || die "Tor didn't declare that there was a problem with the arguments."
 
@@ -418,7 +428,9 @@ ME="${DATA_DIR}/case11C"
 
 mkdir -p "${ME}/keys"
 
-${TOR} --DataDirectory "${ME}" --newpass > "${ME}/stdout" && die "Successfully started with newpass but no keygen?" || true
+if ${TOR} --DataDirectory "${ME}" --newpass > "${ME}/stdout"; then
+  die "Successfully started with newpass but no keygen?"
+fi
 
 grep "newpass specified without --keygen" "${ME}/stdout" >/dev/null || die "Tor didn't declare that there was a problem with the arguments."
 
@@ -456,7 +468,9 @@ ME="${DATA_DIR}/case11E"
 
 mkdir -p "${ME}/keys"
 
-${TOR} --DataDirectory "${ME}" --keygen --passphrase-fd ewigeblumenkraft > "${ME}/stdout" && die "Successfully started with bogus passphrase-fd?" || true
+if ${TOR} --DataDirectory "${ME}" --keygen --passphrase-fd ewigeblumenkraft > "${ME}/stdout"; then
+  die "Successfully started with bogus passphrase-fd?"
+fi
 
 grep "Invalid --passphrase-fd value" "${ME}/stdout" >/dev/null || die "Tor didn't declare that there was a problem with the arguments."
 
@@ -473,7 +487,9 @@ ME="${DATA_DIR}/case11F"
 
 mkdir -p "${ME}/keys"
 
-${TOR} --DataDirectory "${ME}" --keygen --passphrase-fd 1 --no-passphrase > "${ME}/stdout" && die "Successfully started with bogus passphrase-fd combination?" || true
+if ${TOR} --DataDirectory "${ME}" --keygen --passphrase-fd 1 --no-passphrase > "${ME}/stdout"; then
+  die "Successfully started with bogus passphrase-fd combination?"
+fi
 
 grep "no-passphrase specified with --passphrase-fd" "${ME}/stdout" >/dev/null || die "Tor didn't declare that there was a problem with the arguments."
 
diff --git a/src/test/test_link_handshake.c b/src/test/test_link_handshake.c
index 34f59f26c..5e78e1ce4 100644
--- a/src/test/test_link_handshake.c
+++ b/src/test/test_link_handshake.c
@@ -263,7 +263,7 @@ test_link_handshake_certs_ok(void *arg)
     tt_assert(c1->handshake_state->authenticated_rsa);
     tt_assert(! c1->handshake_state->authenticated_ed25519);
   }
-  tt_assert(! tor_mem_is_zero(
+  tt_assert(! fast_mem_is_zero(
                 (char*)c1->handshake_state->authenticated_rsa_peer_id, 20));
 
   chan2 = tor_malloc_zero(sizeof(*chan2));
@@ -290,7 +290,7 @@ test_link_handshake_certs_ok(void *arg)
     tt_ptr_op(c2->handshake_state->certs->ed_id_sign, OP_EQ, NULL);
   }
   tt_assert(c2->handshake_state->certs->id_cert);
-  tt_assert(tor_mem_is_zero(
+  tt_assert(fast_mem_is_zero(
               (char*)c2->handshake_state->authenticated_rsa_peer_id, 20));
   /* no authentication has happened yet, since we haen't gotten an AUTH cell.
    */
@@ -948,7 +948,7 @@ test_link_handshake_send_authchallenge(void *arg)
 #else
   tt_int_op(36, OP_EQ, cell1->payload_len);
   tt_int_op(36, OP_EQ, cell2->payload_len);
-#endif
+#endif /* defined(HAVE_WORKING_TOR_TLS_GET_TLSSECRETS) */
   tt_int_op(0, OP_EQ, cell1->circ_id);
   tt_int_op(0, OP_EQ, cell2->circ_id);
   tt_int_op(CELL_AUTH_CHALLENGE, OP_EQ, cell1->command);
@@ -960,7 +960,7 @@ test_link_handshake_send_authchallenge(void *arg)
 #else
   tt_mem_op("\x00\x01\x00\x03", OP_EQ, cell1->payload + 32, 4);
   tt_mem_op("\x00\x01\x00\x03", OP_EQ, cell2->payload + 32, 4);
-#endif
+#endif /* defined(HAVE_WORKING_TOR_TLS_GET_TLSSECRETS) */
   tt_mem_op(cell1->payload, OP_NE, cell2->payload, 32);
 
  done:
diff --git a/src/test/test_logging.c b/src/test/test_logging.c
index 6416e98a4..bb7018fe1 100644
--- a/src/test/test_logging.c
+++ b/src/test/test_logging.c
@@ -15,7 +15,7 @@
 #endif
 
 static void
-dummy_cb_fn(int severity, uint32_t domain, const char *msg)
+dummy_cb_fn(int severity, log_domain_mask_t domain, const char *msg)
 {
   (void)severity; (void)domain; (void)msg;
 }
diff --git a/src/test/test_namemap.c b/src/test/test_namemap.c
new file mode 100644
index 000000000..df77d4e2d
--- /dev/null
+++ b/src/test/test_namemap.c
@@ -0,0 +1,174 @@
+/* Copyright (c) 2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "test/test.h"
+
+#include "lib/cc/torint.h"
+#include "lib/container/namemap.h"
+#include "lib/container/namemap_st.h"
+#include "lib/malloc/malloc.h"
+
+#include <stdio.h>
+#include <string.h>
+
+static void
+test_namemap_empty(void *arg)
+{
+  (void)arg;
+
+  namemap_t m;
+  namemap_init(&m);
+  namemap_t m2 = NAMEMAP_INIT();
+
+  tt_uint_op(0, OP_EQ, namemap_get_size(&m));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m, "hello"));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m, "hello"));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m, "hello128"));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m, ""));
+  tt_uint_op(0, OP_EQ, namemap_get_size(&m));
+
+  tt_uint_op(0, OP_EQ, namemap_get_size(&m2));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m2, "hello"));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m2, "hello"));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m2, "hello128"));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m2, ""));
+  tt_uint_op(0, OP_EQ, namemap_get_size(&m));
+
+ done:
+  namemap_clear(&m);
+  namemap_clear(&m2);
+}
+
+static void
+test_namemap_toolong(void *arg)
+{
+  (void)arg;
+  namemap_t m;
+  char *ok = NULL;
+  char *toolong = NULL;
+  namemap_init(&m);
+
+  ok = tor_malloc_zero(MAX_NAMEMAP_NAME_LEN+1);
+  memset(ok, 'x', MAX_NAMEMAP_NAME_LEN);
+
+  toolong = tor_malloc_zero(MAX_NAMEMAP_NAME_LEN+2);
+  memset(toolong, 'x', MAX_NAMEMAP_NAME_LEN+1);
+
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m, ok));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m, toolong));
+  unsigned u1 = namemap_get_or_create_id(&m, toolong);
+  unsigned u2 = namemap_get_or_create_id(&m, ok);
+  tt_uint_op(u1, OP_EQ, NAMEMAP_ERR);
+  tt_uint_op(u2, OP_NE, NAMEMAP_ERR);
+  tt_uint_op(u2, OP_EQ, namemap_get_id(&m, ok));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m, toolong));
+
+  tt_str_op(ok, OP_EQ, namemap_get_name(&m, u2));
+  tt_ptr_op(NULL, OP_EQ, namemap_get_name(&m, u1));
+
+ done:
+  tor_free(ok);
+  tor_free(toolong);
+  namemap_clear(&m);
+}
+
+static void
+test_namemap_blackbox(void *arg)
+{
+  (void)arg;
+
+  namemap_t m1, m2;
+  namemap_init(&m1);
+  namemap_init(&m2);
+
+  unsigned u1 = namemap_get_or_create_id(&m1, "hello");
+  unsigned u2 = namemap_get_or_create_id(&m1, "world");
+  tt_uint_op(u1, OP_NE, NAMEMAP_ERR);
+  tt_uint_op(u2, OP_NE, NAMEMAP_ERR);
+  tt_uint_op(u1, OP_NE, u2);
+
+  tt_uint_op(u1, OP_EQ, namemap_get_id(&m1, "hello"));
+  tt_uint_op(u1, OP_EQ, namemap_get_or_create_id(&m1, "hello"));
+  tt_uint_op(u2, OP_EQ, namemap_get_id(&m1, "world"));
+  tt_uint_op(u2, OP_EQ, namemap_get_or_create_id(&m1, "world"));
+
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m1, "HELLO"));
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m2, "hello"));
+
+  unsigned u3 = namemap_get_or_create_id(&m2, "hola");
+  tt_uint_op(u3, OP_NE, NAMEMAP_ERR);
+  tt_uint_op(NAMEMAP_ERR, OP_EQ, namemap_get_id(&m1, "hola"));
+  tt_uint_op(u3, OP_EQ, namemap_get_or_create_id(&m2, "hola"));
+  tt_uint_op(u3, OP_EQ, namemap_get_id(&m2, "hola"));
+
+  unsigned int u4 = namemap_get_or_create_id(&m1, "hola");
+  tt_uint_op(u4, OP_NE, NAMEMAP_ERR);
+  tt_uint_op(u4, OP_EQ, namemap_get_id(&m1, "hola"));
+  tt_uint_op(u3, OP_EQ, namemap_get_id(&m2, "hola"));
+
+  tt_str_op("hello", OP_EQ, namemap_get_name(&m1, u1));
+  tt_str_op("world", OP_EQ, namemap_get_name(&m1, u2));
+  tt_str_op("hola", OP_EQ, namemap_get_name(&m2, u3));
+  tt_str_op("hola", OP_EQ, namemap_get_name(&m1, u4));
+
+  tt_ptr_op(NULL, OP_EQ, namemap_get_name(&m2, u3 + 10));
+
+ done:
+  namemap_clear(&m1);
+  namemap_clear(&m2);
+}
+
+static void
+test_namemap_internals(void *arg)
+{
+  (void)arg;
+  // This test actually assumes know something about the identity layout.
+  namemap_t m;
+  namemap_init(&m);
+
+  tt_uint_op(0, OP_EQ, namemap_get_or_create_id(&m, "that"));
+  tt_uint_op(0, OP_EQ, namemap_get_or_create_id(&m, "that"));
+  tt_uint_op(1, OP_EQ, namemap_get_or_create_id(&m, "is"));
+  tt_uint_op(1, OP_EQ, namemap_get_or_create_id(&m, "is"));
+
+  tt_uint_op(0, OP_EQ, namemap_get_id(&m, "that"));
+  tt_uint_op(0, OP_EQ, namemap_get_id(&m, "that"));
+  tt_uint_op(1, OP_EQ, namemap_get_id(&m, "is"));
+  tt_uint_op(2, OP_EQ, namemap_get_or_create_id(&m, "not"));
+  tt_uint_op(1, OP_EQ, namemap_get_or_create_id(&m, "is"));
+  tt_uint_op(2, OP_EQ, namemap_get_or_create_id(&m, "not"));
+
+ done:
+  namemap_clear(&m);
+}
+
+static void
+test_namemap_fmt(void *arg)
+{
+  (void)arg;
+  namemap_t m = NAMEMAP_INIT();
+
+  unsigned a = namemap_get_or_create_id(&m, "greetings");
+  unsigned b = namemap_get_or_create_id(&m, "earthlings");
+
+  tt_str_op(namemap_fmt_name(&m, a), OP_EQ, "greetings");
+  tt_str_op(namemap_fmt_name(&m, b), OP_EQ, "earthlings");
+  tt_int_op(a, OP_NE, 100);
+  tt_int_op(b, OP_NE, 100);
+  tt_str_op(namemap_fmt_name(&m, 100), OP_EQ, "{100}");
+
+ done:
+  namemap_clear(&m);
+}
+
+#define T(name) \
+  { #name, test_namemap_ ## name , 0, NULL, NULL }
+
+struct testcase_t namemap_tests[] = {
+  T(empty),
+  T(toolong),
+  T(blackbox),
+  T(internals),
+  T(fmt),
+  END_OF_TESTCASES
+};
diff --git a/src/test/test_options.c b/src/test/test_options.c
index f12e6b676..7009910b0 100644
--- a/src/test/test_options.c
+++ b/src/test/test_options.c
@@ -31,14 +31,14 @@
 
 typedef struct {
   int severity;
-  uint32_t domain;
+  log_domain_mask_t domain;
   char *msg;
 } logmsg_t;
 
 static smartlist_t *messages = NULL;
 
 static void
-log_cback(int severity, uint32_t domain, const char *msg)
+log_cback(int severity, log_domain_mask_t domain, const char *msg)
 {
   logmsg_t *x = tor_malloc(sizeof(*x));
   x->severity = severity;
@@ -430,6 +430,7 @@ get_options_test_data(const char *conf)
   // Being kinda lame and just fixing the immedate breakage for now..
   result->opt->ConnectionPadding = -1; // default must be "auto"
   result->opt->DormantClientTimeout = 1800; // must be over 600.
+  result->opt->CircuitPadding = 1; // default must be "1"
 
   rv = config_get_lines(conf, &cl, 1);
   tt_int_op(rv, OP_EQ, 0);
diff --git a/src/test/test_periodic_event.c b/src/test/test_periodic_event.c
index ebac20838..267156a90 100644
--- a/src/test/test_periodic_event.c
+++ b/src/test/test_periodic_event.c
@@ -51,12 +51,13 @@ test_pe_initialize(void *arg)
    * need to run the main loop and then wait for a second delaying the unit
    * tests. Instead, we'll test the callback work indepedently elsewhere. */
   initialize_periodic_events();
+  periodic_events_connect_all();
   set_network_participation(false);
   rescan_periodic_events(get_options());
 
   /* Validate that all events have been set up. */
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_event_item_t *item = &mainloop_periodic_events[i];
     tt_assert(item->ev);
     tt_assert(item->fn);
     tt_u64_op(item->last_action_time, OP_EQ, 0);
@@ -89,8 +90,8 @@ test_pe_launch(void *arg)
   /* Hack: We'll set a dumb fn() of each events so they don't get called when
    * dispatching them. We just want to test the state of the callbacks, not
    * the whole code path. */
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_event_item_t *item = &mainloop_periodic_events[i];
     item->fn = dumb_event_fn;
   }
 
@@ -107,17 +108,18 @@ test_pe_launch(void *arg)
     periodic_event_item_t *item = &periodic_events[i];
     tt_int_op(periodic_event_is_enabled(item), OP_EQ, 0);
   }
-#endif
+#endif /* 0 */
 
   initialize_periodic_events();
+  periodic_events_connect_all();
 
   /* Now that we've initialized, rescan the list to launch. */
   periodic_events_on_new_options(options);
 
   int mask = PERIODIC_EVENT_ROLE_CLIENT|PERIODIC_EVENT_ROLE_ALL|
     PERIODIC_EVENT_ROLE_NET_PARTICIPANT;
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_event_item_t *item = &mainloop_periodic_events[i];
     int should_be_enabled = !!(item->roles & mask);
     tt_int_op(periodic_event_is_enabled(item), OP_EQ, should_be_enabled);
     // enabled or not, the event has not yet been run.
@@ -134,8 +136,8 @@ test_pe_launch(void *arg)
              PERIODIC_EVENT_ROLE_RELAY|PERIODIC_EVENT_ROLE_DIRSERVER|
              PERIODIC_EVENT_ROLE_ALL|PERIODIC_EVENT_ROLE_NET_PARTICIPANT);
 
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_event_item_t *item = &mainloop_periodic_events[i];
     /* Only Client role should be disabled. */
     if (item->roles == PERIODIC_EVENT_ROLE_CLIENT) {
       tt_int_op(periodic_event_is_enabled(item), OP_EQ, 0);
@@ -156,8 +158,8 @@ test_pe_launch(void *arg)
   set_network_participation(false);
   periodic_events_on_new_options(options);
 
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_event_item_t *item = &mainloop_periodic_events[i];
     int should_be_enabled = (item->roles & PERIODIC_EVENT_ROLE_ALL) &&
       !(item->flags & PERIODIC_EVENT_FLAG_NEED_NET);
     tt_int_op(periodic_event_is_enabled(item), OP_EQ, should_be_enabled);
@@ -177,8 +179,8 @@ test_pe_launch(void *arg)
    * trigger a rescan of the event disabling the HS service event. */
   to_remove = &service;
 
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_event_item_t *item = &mainloop_periodic_events[i];
     tt_int_op(periodic_event_is_enabled(item), OP_EQ,
               (item->roles != PERIODIC_EVENT_ROLE_CONTROLEV));
   }
@@ -300,12 +302,13 @@ test_pe_hs_service(void *arg)
   consider_hibernation(time(NULL));
   /* Initialize the events so we can enable them */
   initialize_periodic_events();
+  periodic_events_connect_all();
 
   /* Hack: We'll set a dumb fn() of each events so they don't get called when
    * dispatching them. We just want to test the state of the callbacks, not
    * the whole code path. */
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_event_item_t *item = &mainloop_periodic_events[i];
     item->fn = dumb_event_fn;
   }
 
@@ -318,8 +321,8 @@ test_pe_hs_service(void *arg)
    * trigger a rescan of the event disabling the HS service event. */
   to_remove = &service;
 
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_event_item_t *item = &mainloop_periodic_events[i];
     if (item->roles & PERIODIC_EVENT_ROLE_HS_SERVICE) {
       tt_int_op(periodic_event_is_enabled(item), OP_EQ, 1);
     }
@@ -329,8 +332,8 @@ test_pe_hs_service(void *arg)
   /* Remove the service from the global map, it should trigger a rescan and
    * disable the HS service events. */
   remove_service(get_hs_service_map(), &service);
-  for (int i = 0; periodic_events[i].name; ++i) {
-    periodic_event_item_t *item = &periodic_events[i];
+  for (int i = 0; mainloop_periodic_events[i].name; ++i) {
+    periodic_event_item_t *item = &mainloop_periodic_events[i];
     if (item->roles & PERIODIC_EVENT_ROLE_HS_SERVICE) {
       tt_int_op(periodic_event_is_enabled(item), OP_EQ, 0);
     }
diff --git a/src/test/test_policy.c b/src/test/test_policy.c
index 46d4a1b94..e58bb3d17 100644
--- a/src/test/test_policy.c
+++ b/src/test/test_policy.c
@@ -6,13 +6,18 @@
 
 #include "core/or/or.h"
 #include "app/config/config.h"
+#include "core/or/circuitbuild.h"
 #include "core/or/policies.h"
 #include "feature/dirparse/policy_parse.h"
+#include "feature/hs/hs_common.h"
+#include "feature/hs/hs_descriptor.h"
 #include "feature/relay/router.h"
 #include "lib/encoding/confline.h"
 #include "test/test.h"
+#include "test/log_test_helpers.h"
 
 #include "core/or/addr_policy_st.h"
+#include "core/or/extend_info_st.h"
 #include "core/or/port_cfg_st.h"
 #include "feature/nodelist/node_st.h"
 #include "feature/nodelist/routerinfo_st.h"
@@ -2024,6 +2029,101 @@ test_policies_fascist_firewall_allows_address(void *arg)
                            expect_ap); \
   STMT_END
 
+/* Check that fascist_firewall_choose_address_ls() returns the expected
+ * results. */
+#define CHECK_CHOSEN_ADDR_NULL_LS() \
+  STMT_BEGIN \
+    tor_addr_port_t chosen_ls_ap; \
+    tor_addr_make_null(&chosen_ls_ap.addr, AF_UNSPEC); \
+    chosen_ls_ap.port = 0; \
+    setup_full_capture_of_logs(LOG_WARN); \
+    fascist_firewall_choose_address_ls(NULL, 1, &chosen_ls_ap); \
+    expect_single_log_msg("Unknown or missing link specifiers"); \
+    teardown_capture_of_logs(); \
+  STMT_END
+
+#define CHECK_CHOSEN_ADDR_LS(fake_ls, pref_only, expect_rv, expect_ap) \
+  STMT_BEGIN \
+    tor_addr_port_t chosen_ls_ap; \
+    tor_addr_make_null(&chosen_ls_ap.addr, AF_UNSPEC); \
+    chosen_ls_ap.port = 0; \
+    setup_full_capture_of_logs(LOG_WARN); \
+    fascist_firewall_choose_address_ls(fake_ls, pref_only, &chosen_ls_ap); \
+    if (smartlist_len(fake_ls) == 0) { \
+      expect_single_log_msg("Link specifiers are empty"); \
+    } else { \
+      expect_no_log_entry(); \
+      tt_assert(tor_addr_eq(&(expect_ap).addr, &chosen_ls_ap.addr)); \
+      tt_int_op((expect_ap).port, OP_EQ, chosen_ls_ap.port); \
+    } \
+    teardown_capture_of_logs(); \
+  STMT_END
+
+#define CHECK_LS_LEGACY_ONLY(fake_ls) \
+  STMT_BEGIN \
+    tor_addr_port_t chosen_ls_ap; \
+    tor_addr_make_null(&chosen_ls_ap.addr, AF_UNSPEC); \
+    chosen_ls_ap.port = 0; \
+    setup_full_capture_of_logs(LOG_WARN); \
+    fascist_firewall_choose_address_ls(fake_ls, 0, &chosen_ls_ap); \
+    expect_single_log_msg("None of our link specifiers have IPv4 or IPv6"); \
+    teardown_capture_of_logs(); \
+  STMT_END
+
+#define CHECK_HS_EXTEND_INFO_ADDR_LS(fake_ls, direct_conn, expect_ap) \
+  STMT_BEGIN \
+    curve25519_secret_key_t seckey; \
+    curve25519_secret_key_generate(&seckey, 0); \
+    curve25519_public_key_t pubkey; \
+    curve25519_public_key_generate(&pubkey, &seckey); \
+    setup_full_capture_of_logs(LOG_WARN); \
+    extend_info_t *ei = hs_get_extend_info_from_lspecs(fake_ls, &pubkey, \
+                                                       direct_conn); \
+    if (fake_ls == NULL) { \
+      tt_ptr_op(ei, OP_EQ, NULL); \
+      expect_single_log_msg("Specified link specifiers is null"); \
+    } else { \
+      expect_no_log_entry(); \
+      tt_assert(tor_addr_eq(&(expect_ap).addr, &ei->addr)); \
+      tt_int_op((expect_ap).port, OP_EQ, ei->port); \
+      extend_info_free(ei); \
+    } \
+    teardown_capture_of_logs(); \
+  STMT_END
+
+#define CHECK_HS_EXTEND_INFO_ADDR_LS_NULL_KEY(fake_ls) \
+  STMT_BEGIN \
+    setup_full_capture_of_logs(LOG_WARN); \
+    extend_info_t *ei = hs_get_extend_info_from_lspecs(fake_ls, NULL, 0); \
+    tt_ptr_op(ei, OP_EQ, NULL); \
+    expect_single_log_msg("Specified onion key is null"); \
+    teardown_capture_of_logs(); \
+  STMT_END
+
+#define CHECK_HS_EXTEND_INFO_ADDR_LS_EXPECT_NULL(fake_ls, direct_conn) \
+  STMT_BEGIN \
+    curve25519_secret_key_t seckey; \
+    curve25519_secret_key_generate(&seckey, 0); \
+    curve25519_public_key_t pubkey; \
+    curve25519_public_key_generate(&pubkey, &seckey); \
+    extend_info_t *ei = hs_get_extend_info_from_lspecs(fake_ls, &pubkey, \
+                                                       direct_conn); \
+    tt_ptr_op(ei, OP_EQ, NULL); \
+  STMT_END
+
+#define CHECK_HS_EXTEND_INFO_ADDR_LS_EXPECT_MSG(fake_ls, msg_level, msg) \
+  STMT_BEGIN \
+    curve25519_secret_key_t seckey; \
+    curve25519_secret_key_generate(&seckey, 0); \
+    curve25519_public_key_t pubkey; \
+    curve25519_public_key_generate(&pubkey, &seckey); \
+    setup_full_capture_of_logs(msg_level); \
+    extend_info_t *ei = hs_get_extend_info_from_lspecs(fake_ls, &pubkey, 0); \
+    tt_ptr_op(ei, OP_EQ, NULL); \
+    expect_single_log_msg(msg); \
+    teardown_capture_of_logs(); \
+  STMT_END
+
 /** Mock the preferred address function to return zero (prefer IPv4). */
 static int
 mock_fascist_firewall_rand_prefer_ipv6_addr_use_ipv4(void)
@@ -2472,6 +2572,141 @@ test_policies_fascist_firewall_choose_address(void *arg)
 
   UNMOCK(fascist_firewall_rand_prefer_ipv6_addr);
 
+  /* Test firewall_choose_address_ls(). To do this, we make a fake link
+   * specifier. */
+  smartlist_t *lspecs = smartlist_new(),
+              *lspecs_blank = smartlist_new(),
+              *lspecs_v4 = smartlist_new(),
+              *lspecs_v6 = smartlist_new(),
+              *lspecs_no_legacy = smartlist_new(),
+              *lspecs_legacy_only = smartlist_new();
+  link_specifier_t *fake_ls;
+
+  /* IPv4 link specifier */
+  fake_ls = link_specifier_new();
+  link_specifier_set_ls_type(fake_ls, LS_IPV4);
+  link_specifier_set_un_ipv4_addr(fake_ls,
+                                  tor_addr_to_ipv4h(&ipv4_or_ap.addr));
+  link_specifier_set_un_ipv4_port(fake_ls, ipv4_or_ap.port);
+  link_specifier_set_ls_len(fake_ls, sizeof(ipv4_or_ap.addr.addr.in_addr) +
+                            sizeof(ipv4_or_ap.port));
+  smartlist_add(lspecs, fake_ls);
+  smartlist_add(lspecs_v4, fake_ls);
+  smartlist_add(lspecs_no_legacy, fake_ls);
+
+  /* IPv6 link specifier */
+  fake_ls = link_specifier_new();
+  link_specifier_set_ls_type(fake_ls, LS_IPV6);
+  size_t addr_len = link_specifier_getlen_un_ipv6_addr(fake_ls);
+  const uint8_t *in6_addr = tor_addr_to_in6_addr8(&ipv6_or_ap.addr);
+  uint8_t *ipv6_array = link_specifier_getarray_un_ipv6_addr(fake_ls);
+  memcpy(ipv6_array, in6_addr, addr_len);
+  link_specifier_set_un_ipv6_port(fake_ls, ipv6_or_ap.port);
+  link_specifier_set_ls_len(fake_ls, addr_len + sizeof(ipv6_or_ap.port));
+  smartlist_add(lspecs, fake_ls);
+  smartlist_add(lspecs_v6, fake_ls);
+
+  /* Legacy ID link specifier */
+  fake_ls = link_specifier_new();
+  link_specifier_set_ls_type(fake_ls, LS_LEGACY_ID);
+  uint8_t *legacy_id = link_specifier_getarray_un_legacy_id(fake_ls);
+  memset(legacy_id, 'A', sizeof(*legacy_id));
+  link_specifier_set_ls_len(fake_ls,
+                            link_specifier_getlen_un_legacy_id(fake_ls));
+  smartlist_add(lspecs, fake_ls);
+  smartlist_add(lspecs_legacy_only, fake_ls);
+  smartlist_add(lspecs_v4, fake_ls);
+  smartlist_add(lspecs_v6, fake_ls);
+
+  /* Check with bogus requests. */
+  tor_addr_port_t null_ap; \
+  tor_addr_make_null(&null_ap.addr, AF_UNSPEC); \
+  null_ap.port = 0; \
+
+  /* Check for a null link state. */
+  CHECK_CHOSEN_ADDR_NULL_LS();
+  CHECK_HS_EXTEND_INFO_ADDR_LS(NULL, 1, null_ap);
+
+  /* Check for a blank link state. */
+  CHECK_CHOSEN_ADDR_LS(lspecs_blank, 0, 0, null_ap);
+  CHECK_HS_EXTEND_INFO_ADDR_LS_EXPECT_NULL(lspecs_blank, 0);
+
+  /* Check for a link state with only a Legacy ID. */
+  CHECK_LS_LEGACY_ONLY(lspecs_legacy_only);
+  CHECK_HS_EXTEND_INFO_ADDR_LS_EXPECT_NULL(lspecs_legacy_only, 0);
+  smartlist_free(lspecs_legacy_only);
+
+  /* Check with a null onion_key. */
+  CHECK_HS_EXTEND_INFO_ADDR_LS_NULL_KEY(lspecs_blank);
+  smartlist_free(lspecs_blank);
+
+  /* Check with a null onion_key. */
+  CHECK_HS_EXTEND_INFO_ADDR_LS_EXPECT_MSG(lspecs_no_legacy, LOG_WARN,
+                                          "Missing Legacy ID in link state");
+  smartlist_free(lspecs_no_legacy);
+
+  /* Enable both IPv4 and IPv6. */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 1;
+  mock_options.ClientUseIPv6 = 1;
+
+  /* Prefer IPv4, enable both IPv4 and IPv6. */
+  mock_options.ClientPreferIPv6ORPort = 0;
+
+  CHECK_CHOSEN_ADDR_LS(lspecs, 0, 1, ipv4_or_ap);
+  CHECK_CHOSEN_ADDR_LS(lspecs, 1, 1, ipv4_or_ap);
+
+  CHECK_HS_EXTEND_INFO_ADDR_LS(lspecs, 1, ipv4_or_ap);
+  CHECK_HS_EXTEND_INFO_ADDR_LS(lspecs, 0, ipv4_or_ap);
+
+  /* Prefer IPv6, enable both IPv4 and IPv6. */
+  mock_options.ClientPreferIPv6ORPort = 1;
+
+  CHECK_CHOSEN_ADDR_LS(lspecs, 0, 1, ipv6_or_ap);
+  CHECK_CHOSEN_ADDR_LS(lspecs, 1, 1, ipv6_or_ap);
+
+  CHECK_HS_EXTEND_INFO_ADDR_LS(lspecs, 1, ipv6_or_ap);
+  CHECK_HS_EXTEND_INFO_ADDR_LS(lspecs, 0, ipv4_or_ap);
+
+  /* IPv4-only. */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 1;
+  mock_options.ClientUseIPv6 = 0;
+
+  CHECK_CHOSEN_ADDR_LS(lspecs, 0, 1, ipv4_or_ap);
+  CHECK_CHOSEN_ADDR_LS(lspecs, 1, 1, ipv4_or_ap);
+
+  CHECK_CHOSEN_ADDR_LS(lspecs_v6, 0, 0, null_ap);
+
+  CHECK_HS_EXTEND_INFO_ADDR_LS(lspecs, 1, ipv4_or_ap);
+  CHECK_HS_EXTEND_INFO_ADDR_LS(lspecs, 0, ipv4_or_ap);
+
+  CHECK_HS_EXTEND_INFO_ADDR_LS_EXPECT_NULL(lspecs_v6, 0);
+  CHECK_HS_EXTEND_INFO_ADDR_LS_EXPECT_NULL(lspecs_v6, 1);
+
+  /* IPv6-only. */
+  memset(&mock_options, 0, sizeof(or_options_t));
+  mock_options.ClientUseIPv4 = 0;
+  mock_options.ClientUseIPv6 = 1;
+
+  CHECK_CHOSEN_ADDR_LS(lspecs, 0, 1, ipv6_or_ap);
+  CHECK_CHOSEN_ADDR_LS(lspecs, 1, 1, ipv6_or_ap);
+
+  CHECK_CHOSEN_ADDR_LS(lspecs_v4, 0, 0, null_ap);
+
+  CHECK_HS_EXTEND_INFO_ADDR_LS(lspecs, 1, ipv6_or_ap);
+  CHECK_HS_EXTEND_INFO_ADDR_LS(lspecs, 0, ipv4_or_ap);
+
+  CHECK_HS_EXTEND_INFO_ADDR_LS_EXPECT_NULL(lspecs_v4, 1);
+  CHECK_HS_EXTEND_INFO_ADDR_LS_EXPECT_NULL(lspecs_v6, 0);
+
+  smartlist_free(lspecs_v4);
+  smartlist_free(lspecs_v6);
+
+  SMARTLIST_FOREACH(lspecs, link_specifier_t *, lspec, \
+                    link_specifier_free(lspec)); \
+  smartlist_free(lspecs);
+
  done:
   UNMOCK(get_options);
 }
diff --git a/src/test/test_prob_distr.c b/src/test/test_prob_distr.c
index 37cfdae7d..0ecbf65f4 100644
--- a/src/test/test_prob_distr.c
+++ b/src/test/test_prob_distr.c
@@ -33,6 +33,7 @@
 #include "lib/math/prob_distr.h"
 #include "lib/math/fp.h"
 #include "lib/crypt_ops/crypto_rand.h"
+#include "test/rng_test_helpers.h"
 
 #include <float.h>
 #include <math.h>
@@ -1117,49 +1118,15 @@ test_psi_dist_sample(const struct dist *dist)
   }
 }
 
-/* This is the seed of the deterministic randomness */
-static uint8_t rng_seed[16];
-static crypto_xof_t *rng_xof = NULL;
-
-/** Initialize the seed of the deterministic randomness. */
-static void
-init_deterministic_rand(void)
-{
-  crypto_rand((char*)rng_seed, sizeof(rng_seed));
-  crypto_xof_free(rng_xof);
-  rng_xof = crypto_xof_new();
-  crypto_xof_add_bytes(rng_xof, rng_seed, sizeof(rng_seed));
-}
-
 static void
-teardown_deterministic_rand(void)
+write_stochastic_warning(void)
 {
-  crypto_xof_free(rng_xof);
-}
-
-static void
-dump_seed(void)
-{
-  printf("\n"
+  if (tinytest_cur_test_has_failed()) {
+    printf("\n"
          "NOTE: This is a stochastic test, and we expect it to fail from\n"
          "time to time, with some low probability. If you see it fail more\n"
-         "than one trial in 100, though, please tell us.\n\n"
-         "Seed: %s\n",
-         hex_str((const char*)rng_seed, sizeof(rng_seed)));
-}
-
-/** Produce deterministic randomness for the stochastic tests using the global
- *  deterministic_rand_counter seed
- *
- *  This function produces deterministic data over multiple calls iff it's
- *  called in the same call order with the same 'n' parameter (which is the
- *  case for the psi test). If not, outputs will deviate. */
-static void
-crypto_rand_deterministic(char *out, size_t n)
-{
-  /* Use a XOF to squeeze bytes out of that silly counter */
-  tor_assert(rng_xof);
-  crypto_xof_squeeze_bytes(rng_xof, (uint8_t*)out, n);
+         "than one trial in 100, though, please tell us.\n\n");
+  }
 }
 
 static void
@@ -1199,8 +1166,7 @@ test_stochastic_uniform(void *arg)
   };
   bool ok = true, tests_failed = true;
 
-  init_deterministic_rand();
-  MOCK(crypto_rand, crypto_rand_deterministic);
+  testing_enable_reproducible_rng();
 
   ok &= test_psi_dist_sample(&uniform01.base);
   ok &= test_psi_dist_sample(&uniform_pos.base);
@@ -1215,10 +1181,9 @@ test_stochastic_uniform(void *arg)
 
  done:
   if (tests_failed) {
-    dump_seed();
+    write_stochastic_warning();
   }
-  teardown_deterministic_rand();
-  UNMOCK(crypto_rand);
+  testing_disable_reproducible_rng();
 }
 
 static bool
@@ -1288,8 +1253,7 @@ test_stochastic_genpareto(void *arg)
   bool tests_failed = true;
   (void) arg;
 
-  init_deterministic_rand();
-  MOCK(crypto_rand, crypto_rand_deterministic);
+  testing_enable_reproducible_rng();
 
   ok = test_stochastic_genpareto_impl(0, 1, -0.25);
   tt_assert(ok);
@@ -1310,10 +1274,9 @@ test_stochastic_genpareto(void *arg)
 
  done:
   if (tests_failed) {
-    dump_seed();
+    write_stochastic_warning();
   }
-  teardown_deterministic_rand();
-  UNMOCK(crypto_rand);
+  testing_disable_reproducible_rng();
 }
 
 static void
@@ -1324,8 +1287,7 @@ test_stochastic_geometric(void *arg)
 
   (void) arg;
 
-  init_deterministic_rand();
-  MOCK(crypto_rand, crypto_rand_deterministic);
+  testing_enable_reproducible_rng();
 
   ok = test_stochastic_geometric_impl(0.1);
   tt_assert(ok);
@@ -1340,10 +1302,9 @@ test_stochastic_geometric(void *arg)
 
  done:
   if (tests_failed) {
-    dump_seed();
+    write_stochastic_warning();
   }
-  teardown_deterministic_rand();
-  UNMOCK(crypto_rand);
+  testing_disable_reproducible_rng();
 }
 
 static void
@@ -1353,8 +1314,7 @@ test_stochastic_logistic(void *arg)
   bool tests_failed = true;
   (void) arg;
 
-  init_deterministic_rand();
-  MOCK(crypto_rand, crypto_rand_deterministic);
+  testing_enable_reproducible_rng();
 
   ok = test_stochastic_logistic_impl(0, 1);
   tt_assert(ok);
@@ -1369,21 +1329,18 @@ test_stochastic_logistic(void *arg)
 
  done:
   if (tests_failed) {
-    dump_seed();
+    write_stochastic_warning();
   }
-  teardown_deterministic_rand();
-  UNMOCK(crypto_rand);
+  testing_disable_reproducible_rng();
 }
 
 static void
 test_stochastic_log_logistic(void *arg)
 {
   bool ok = 0;
-  bool tests_failed = true;
   (void) arg;
 
-  init_deterministic_rand();
-  MOCK(crypto_rand, crypto_rand_deterministic);
+  testing_enable_reproducible_rng();
 
   ok = test_stochastic_log_logistic_impl(1, 1);
   tt_assert(ok);
@@ -1394,25 +1351,18 @@ test_stochastic_log_logistic(void *arg)
   ok = test_stochastic_log_logistic_impl(exp(-10), 1e-2);
   tt_assert(ok);
 
-  tests_failed = false;
-
  done:
-  if (tests_failed) {
-    dump_seed();
-  }
-  teardown_deterministic_rand();
-  UNMOCK(crypto_rand);
+  write_stochastic_warning();
+  testing_disable_reproducible_rng();
 }
 
 static void
 test_stochastic_weibull(void *arg)
 {
   bool ok = 0;
-  bool tests_failed = true;
   (void) arg;
 
-  init_deterministic_rand();
-  MOCK(crypto_rand, crypto_rand_deterministic);
+  testing_enable_reproducible_rng();
 
   ok = test_stochastic_weibull_impl(1, 0.5);
   tt_assert(ok);
@@ -1425,13 +1375,9 @@ test_stochastic_weibull(void *arg)
   ok = test_stochastic_weibull_impl(10, 1);
   tt_assert(ok);
 
-  tests_failed = false;
-
  done:
-  if (tests_failed) {
-    dump_seed();
-  }
-  teardown_deterministic_rand();
+  write_stochastic_warning();
+  testing_disable_reproducible_rng();
   UNMOCK(crypto_rand);
 }
 
diff --git a/src/test/test_process.c b/src/test/test_process.c
index 7cc01d244..783631276 100644
--- a/src/test/test_process.c
+++ b/src/test/test_process.c
@@ -594,7 +594,7 @@ test_unix(void *arg)
 
  done:
   process_free(process);
-#endif
+#endif /* !defined(_WIN32) */
 }
 
 static void
@@ -649,7 +649,7 @@ test_win32(void *arg)
  done:
   tor_free(joined_argv);
   process_free(process);
-#endif
+#endif /* defined(_WIN32) */
 }
 
 struct testcase_t process_tests[] = {
diff --git a/src/test/test_process_slow.c b/src/test/test_process_slow.c
index 1322d7b83..91252c725 100644
--- a/src/test/test_process_slow.c
+++ b/src/test/test_process_slow.c
@@ -135,7 +135,7 @@ get_win32_test_binary_path(void)
  done:
   return NULL;
 }
-#endif
+#endif /* defined(_WIN32) */
 
 static void
 main_loop_timeout_cb(periodic_timer_t *timer, void *data)
diff --git a/src/test/test_protover.c b/src/test/test_protover.c
index 63c508bd1..1759aef97 100644
--- a/src/test/test_protover.c
+++ b/src/test/test_protover.c
@@ -22,7 +22,7 @@ test_protover_parse(void *arg)
   tt_skip();
  done:
   ;
-#else
+#else /* !(defined(HAVE_RUST)) */
   char *re_encoded = NULL;
 
   const char *orig = "Foo=1,3 Bar=3 Baz= Quux=9-12,14,15-16,900";
@@ -89,7 +89,7 @@ test_protover_parse(void *arg)
     SMARTLIST_FOREACH(elts, proto_entry_t *, ent, proto_entry_free(ent));
   smartlist_free(elts);
   tor_free(re_encoded);
-#endif
+#endif /* defined(HAVE_RUST) */
 }
 
 static void
@@ -133,7 +133,7 @@ test_protover_parse_fail(void *arg)
                            "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
   tt_ptr_op(elts, OP_EQ, NULL);
 
-#endif
+#endif /* defined(HAVE_RUST) */
  done:
   ;
 }
@@ -335,7 +335,7 @@ test_protover_all_supported(void *arg)
                  "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
                  "aaaaaaaaaaaa=1-65536", &msg));
   tor_end_capture_bugs_();
-#endif
+#endif /* !defined(HAVE_RUST) */
 
  done:
   tor_end_capture_bugs_();
@@ -459,7 +459,7 @@ test_protover_supported_protocols(void *arg)
   tt_assert(protocol_list_supports_protocol(supported_protocols,
                                             PRT_LINKAUTH,
                                             PROTOVER_LINKAUTH_V1));
-#endif
+#endif /* defined(HAVE_WORKING_TOR_TLS_GET_TLSSECRETS) */
   /* Latest LinkAuth is not exposed in the headers. */
   tt_assert(protocol_list_supports_protocol(supported_protocols,
                                             PRT_LINKAUTH,
diff --git a/src/test/test_pt.c b/src/test/test_pt.c
index d2996f4cc..87e3ba356 100644
--- a/src/test/test_pt.c
+++ b/src/test/test_pt.c
@@ -7,12 +7,13 @@
 #define PT_PRIVATE
 #define UTIL_PRIVATE
 #define STATEFILE_PRIVATE
-#define CONTROL_PRIVATE
+#define CONTROL_EVENTS_PRIVATE
 #define PROCESS_PRIVATE
 #include "core/or/or.h"
 #include "app/config/config.h"
 #include "app/config/confparse.h"
 #include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "feature/client/transports.h"
 #include "core/or/circuitbuild.h"
 #include "app/config/statefile.h"
diff --git a/src/test/test_ptr_slow.c b/src/test/test_ptr_slow.c
new file mode 100644
index 000000000..76bdbf189
--- /dev/null
+++ b/src/test/test_ptr_slow.c
@@ -0,0 +1,106 @@
+/* Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "orconfig.h"
+#include "core/or/or.h"
+#include "test/test.h"
+#include "test/ptr_helpers.h"
+
+#include <stdint.h>
+#include <limits.h>
+
+/** Assert that <b>a</b> can be cast to void * and back. */
+static void
+assert_int_voidptr_roundtrip(int a)
+{
+  intptr_t ap = (intptr_t)a;
+  void *b = cast_intptr_to_voidstar(ap);
+  intptr_t c = cast_voidstar_to_intptr(b);
+  void *d = cast_intptr_to_voidstar(c);
+
+  tt_assert(ap == c);
+  tt_assert(b == d);
+
+ done:
+  return;
+}
+
+/** Test for possibility of casting `int` to `void *` and back. */
+static void
+test_int_voidstar_interop(void *arg)
+{
+  int a;
+  (void)arg;
+
+  for (a = -1024; a <= 1024; a++) {
+    assert_int_voidptr_roundtrip(a);
+  }
+
+  for (a = INT_MIN; a <= INT_MIN+1024; a++) {
+    assert_int_voidptr_roundtrip(a);
+  }
+
+  for (a = INT_MAX-1024; a < INT_MAX; a++) {
+    assert_int_voidptr_roundtrip(a);
+  }
+
+  a = 1;
+  for (unsigned long i = 0; i < sizeof(int) * 8; i++) {
+    assert_int_voidptr_roundtrip(a);
+    a = (a << 1);
+  }
+}
+
+/** Assert that <b>a</b> can be cast to void * and back. */
+static void
+assert_uint_voidptr_roundtrip(unsigned int a)
+{
+ uintptr_t ap = (uintptr_t)a;
+ void *b = cast_uintptr_to_voidstar(ap);
+ uintptr_t c = cast_voidstar_to_uintptr(b);
+ void *d = cast_uintptr_to_voidstar(c);
+
+ tt_assert(ap == c);
+ tt_assert(b == d);
+
+ done:
+  return;
+}
+
+/** Test for possibility of casting `int` to `void *` and back. */
+static void
+test_uint_voidstar_interop(void *arg)
+{
+  unsigned int a;
+  (void)arg;
+
+  for (a = 0; a <= 1024; a++) {
+    assert_uint_voidptr_roundtrip(a);
+  }
+
+  for (a = UINT_MAX-1024; a < UINT_MAX; a++) {
+    assert_uint_voidptr_roundtrip(a);
+  }
+
+  a = 1;
+  for (unsigned long i = 0; i < sizeof(int) * 8; i++) {
+    assert_uint_voidptr_roundtrip(a);
+    a = (a << 1);
+  }
+}
+
+struct testcase_t slow_ptr_tests[] = {
+  { .name = "int_voidstar_interop",
+    .fn = test_int_voidstar_interop,
+    .flags = 0,
+    .setup = NULL,
+    .setup_data = NULL },
+  { .name = "uint_voidstar_interop",
+    .fn = test_uint_voidstar_interop,
+    .flags = 0,
+    .setup = NULL,
+    .setup_data = NULL },
+  END_OF_TESTCASES
+};
diff --git a/src/test/test_pubsub_build.c b/src/test/test_pubsub_build.c
new file mode 100644
index 000000000..ce5bf6008
--- /dev/null
+++ b/src/test/test_pubsub_build.c
@@ -0,0 +1,621 @@
+/* Copyright (c) 2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#define DISPATCH_PRIVATE
+#define PUBSUB_PRIVATE
+
+#include "test/test.h"
+
+#include "lib/cc/torint.h"
+#include "lib/dispatch/dispatch.h"
+#include "lib/dispatch/dispatch_naming.h"
+#include "lib/dispatch/dispatch_st.h"
+#include "lib/dispatch/msgtypes.h"
+#include "lib/pubsub/pubsub_macros.h"
+#include "lib/pubsub/pubsub_build.h"
+#include "lib/pubsub/pubsub_builder_st.h"
+
+#include "lib/log/escape.h"
+#include "lib/malloc/malloc.h"
+#include "lib/string/printf.h"
+
+#include "test/log_test_helpers.h"
+
+#include <stdio.h>
+#include <string.h>
+
+static char *
+ex_int_fmt(msg_aux_data_t aux)
+{
+  int val = (int) aux.u64;
+  char *r=NULL;
+  tor_asprintf(&r, "%d", val);
+  return r;
+}
+
+static char *
+ex_str_fmt(msg_aux_data_t aux)
+{
+  return esc_for_log(aux.ptr);
+}
+
+static void
+ex_str_free(msg_aux_data_t aux)
+{
+  tor_free_(aux.ptr);
+}
+
+static dispatch_typefns_t intfns = {
+  .fmt_fn = ex_int_fmt
+};
+
+static dispatch_typefns_t stringfns = {
+  .free_fn = ex_str_free,
+  .fmt_fn = ex_str_fmt
+};
+
+DECLARE_MESSAGE_INT(bunch_of_coconuts, int, int);
+DECLARE_PUBLISH(bunch_of_coconuts);
+DECLARE_SUBSCRIBE(bunch_of_coconuts, coconut_recipient_cb);
+
+DECLARE_MESSAGE(yes_we_have_no, string, char *);
+DECLARE_PUBLISH(yes_we_have_no);
+DECLARE_SUBSCRIBE(yes_we_have_no, absent_item_cb);
+
+static void
+coconut_recipient_cb(const msg_t *m, int n_coconuts)
+{
+  (void)m;
+  (void)n_coconuts;
+}
+
+static void
+absent_item_cb(const msg_t *m, const char *fruitname)
+{
+  (void)m;
+  (void)fruitname;
+}
+
+#define FLAG_SKIP 99999
+
+static void
+seed_dispatch_builder(pubsub_builder_t *b,
+                      unsigned fl1, unsigned fl2, unsigned fl3, unsigned fl4)
+{
+  pubsub_connector_t *c = NULL;
+
+  {
+    c = pubsub_connector_for_subsystem(b, get_subsys_id("sys1"));
+    DISPATCH_REGISTER_TYPE(c, int, &intfns);
+    if (fl1 != FLAG_SKIP)
+      DISPATCH_ADD_PUB_(c, main, bunch_of_coconuts, fl1);
+    if (fl2 != FLAG_SKIP)
+      DISPATCH_ADD_SUB_(c, main, yes_we_have_no, fl2);
+    pubsub_connector_free(c);
+  }
+
+  {
+    c = pubsub_connector_for_subsystem(b, get_subsys_id("sys2"));
+    DISPATCH_REGISTER_TYPE(c, string, &stringfns);
+    if (fl3 != FLAG_SKIP)
+      DISPATCH_ADD_PUB_(c, main, yes_we_have_no, fl3);
+    if (fl4 != FLAG_SKIP)
+      DISPATCH_ADD_SUB_(c, main, bunch_of_coconuts, fl4);
+    pubsub_connector_free(c);
+  }
+}
+
+static void
+seed_pubsub_builder_basic(pubsub_builder_t *b)
+{
+  seed_dispatch_builder(b, 0, 0, 0, 0);
+}
+
+/* Regular builder with valid types and messages.
+ */
+static void
+test_pubsub_build_types_ok(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+  pubsub_connector_t *c = NULL;
+  pubsub_items_t *items = NULL;
+
+  b = pubsub_builder_new();
+  seed_pubsub_builder_basic(b);
+
+  dispatcher = pubsub_builder_finalize(b, &items);
+  b = NULL;
+  tt_assert(dispatcher);
+  tt_assert(items);
+  tt_int_op(smartlist_len(items->items), OP_EQ, 4);
+
+  // Make sure that the bindings got build correctly.
+  SMARTLIST_FOREACH_BEGIN(items->items, pubsub_cfg_t *, item) {
+    if (item->is_publish) {
+      tt_assert(item->pub_binding);
+      tt_ptr_op(item->pub_binding->dispatch_ptr, OP_EQ, dispatcher);
+    }
+  } SMARTLIST_FOREACH_END(item);
+
+  tt_int_op(dispatcher->n_types, OP_GE, 2);
+  tt_assert(dispatcher->typefns);
+
+  tt_assert(dispatcher->typefns[get_msg_type_id("int")].fmt_fn == ex_int_fmt);
+  tt_assert(dispatcher->typefns[get_msg_type_id("string")].fmt_fn ==
+            ex_str_fmt);
+
+  // Now clear the bindings, like we would do before freeing the
+  // the dispatcher.
+  pubsub_items_clear_bindings(items);
+  SMARTLIST_FOREACH_BEGIN(items->items, pubsub_cfg_t *, item) {
+    if (item->is_publish) {
+      tt_assert(item->pub_binding);
+      tt_ptr_op(item->pub_binding->dispatch_ptr, OP_EQ, NULL);
+    }
+  } SMARTLIST_FOREACH_END(item);
+
+ done:
+  pubsub_connector_free(c);
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  pubsub_items_free(items);
+}
+
+/* We fail if the same type is defined in two places with different functions.
+ */
+static void
+test_pubsub_build_types_decls_conflict(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+  pubsub_connector_t *c = NULL;
+
+  b = pubsub_builder_new();
+  seed_pubsub_builder_basic(b);
+  {
+    c = pubsub_connector_for_subsystem(b, get_subsys_id("sys3"));
+    // Extra declaration of int: we don't allow this.
+    DISPATCH_REGISTER_TYPE(c, int, &stringfns);
+    pubsub_connector_free(c);
+  }
+
+  setup_full_capture_of_logs(LOG_WARN);
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher == NULL);
+  // expect_log_msg_containing("(int) declared twice"); // XXXX
+
+ done:
+  pubsub_connector_free(c);
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  teardown_capture_of_logs();
+}
+
+/* If a message ID exists but nobody is publishing or subscribing to it,
+ * that's okay. */
+static void
+test_pubsub_build_unused_message(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+
+  b = pubsub_builder_new();
+  seed_pubsub_builder_basic(b);
+
+  // This message isn't actually generated by anyone, but that will be fine:
+  // we just log it at info.
+  get_message_id("unused");
+  setup_capture_of_logs(LOG_INFO);
+
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher);
+  expect_log_msg_containing(
+     "Nobody is publishing or subscribing to message");
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  teardown_capture_of_logs();
+}
+
+/* Publishing or subscribing to a message with no subscribers / publishers
+ * should fail and warn. */
+static void
+test_pubsub_build_missing_pubsub(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+
+  b = pubsub_builder_new();
+  seed_dispatch_builder(b, 0, 0, FLAG_SKIP, FLAG_SKIP);
+
+  setup_full_capture_of_logs(LOG_WARN);
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher == NULL);
+
+  expect_log_msg_containing(
+       "Message \"bunch_of_coconuts\" has publishers, but no subscribers.");
+  expect_log_msg_containing(
+       "Message \"yes_we_have_no\" has subscribers, but no publishers.");
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  teardown_capture_of_logs();
+}
+
+/* Make sure that a stub publisher or subscriber prevents an error from
+ * happening even if there are no other publishers/subscribers for a message
+ */
+static void
+test_pubsub_build_stub_pubsub(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+
+  b = pubsub_builder_new();
+  seed_dispatch_builder(b, 0, 0, DISP_FLAG_STUB, DISP_FLAG_STUB);
+
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher);
+
+  // 1 subscriber.
+  tt_int_op(1, OP_EQ,
+            dispatcher->table[get_message_id("yes_we_have_no")]->n_enabled);
+  // no subscribers
+  tt_ptr_op(NULL, OP_EQ,
+            dispatcher->table[get_message_id("bunch_of_coconuts")]);
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+}
+
+/* Only one channel per msg id. */
+static void
+test_pubsub_build_channels_conflict(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+  pubsub_connector_t *c = NULL;
+
+  b = pubsub_builder_new();
+  seed_pubsub_builder_basic(b);
+  pub_binding_t btmp;
+
+  {
+    c = pubsub_connector_for_subsystem(b, get_subsys_id("problems"));
+    /* Usually the DISPATCH_ADD_PUB macro would keep us from using
+     * the wrong channel */
+    pubsub_add_pub_(c, &btmp, get_channel_id("hithere"),
+                    get_message_id("bunch_of_coconuts"),
+                    get_msg_type_id("int"),
+                    0 /* flags */,
+                    "somewhere.c", 22);
+    pubsub_connector_free(c);
+  };
+
+  setup_full_capture_of_logs(LOG_WARN);
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher == NULL);
+
+  expect_log_msg_containing("Message \"bunch_of_coconuts\" is associated "
+                            "with multiple inconsistent channels.");
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  teardown_capture_of_logs();
+}
+
+/* Only one type per msg id. */
+static void
+test_pubsub_build_types_conflict(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+  pubsub_connector_t *c = NULL;
+
+  b = pubsub_builder_new();
+  seed_pubsub_builder_basic(b);
+  pub_binding_t btmp;
+
+  {
+    c = pubsub_connector_for_subsystem(b, get_subsys_id("problems"));
+    /* Usually the DISPATCH_ADD_PUB macro would keep us from using
+     * the wrong channel */
+    pubsub_add_pub_(c, &btmp, get_channel_id("hithere"),
+                    get_message_id("bunch_of_coconuts"),
+                    get_msg_type_id("string"),
+                    0 /* flags */,
+                    "somewhere.c", 22);
+    pubsub_connector_free(c);
+  };
+
+  setup_full_capture_of_logs(LOG_WARN);
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher == NULL);
+
+  expect_log_msg_containing("Message \"bunch_of_coconuts\" is associated "
+                            "with multiple inconsistent message types.");
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  teardown_capture_of_logs();
+}
+
+/* The same module can't publish and subscribe the same message */
+static void
+test_pubsub_build_pubsub_same(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+  pubsub_connector_t *c = NULL;
+
+  b = pubsub_builder_new();
+  seed_pubsub_builder_basic(b);
+
+  {
+    c = pubsub_connector_for_subsystem(b, get_subsys_id("sys1"));
+    // already publishing this.
+    DISPATCH_ADD_SUB(c, main, bunch_of_coconuts);
+    pubsub_connector_free(c);
+  };
+
+  setup_full_capture_of_logs(LOG_WARN);
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher == NULL);
+
+  expect_log_msg_containing("Message \"bunch_of_coconuts\" is published "
+                            "and subscribed by the same subsystem \"sys1\".");
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  teardown_capture_of_logs();
+}
+
+/* More than one subsystem may publish or subscribe, and that's okay. */
+static void
+test_pubsub_build_pubsub_multi(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+  pubsub_connector_t *c = NULL;
+
+  b = pubsub_builder_new();
+  seed_pubsub_builder_basic(b);
+  pub_binding_t btmp;
+
+  {
+    c = pubsub_connector_for_subsystem(b, get_subsys_id("sys3"));
+    DISPATCH_ADD_SUB(c, main, bunch_of_coconuts);
+    pubsub_add_pub_(c, &btmp, get_channel_id("main"),
+                    get_message_id("yes_we_have_no"),
+                    get_msg_type_id("string"),
+                    0 /* flags */,
+                    "somewhere.c", 22);
+    pubsub_connector_free(c);
+  };
+
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher);
+
+  // 1 subscribers
+  tt_int_op(1, OP_EQ,
+            dispatcher->table[get_message_id("yes_we_have_no")]->n_enabled);
+  // 2 subscribers.
+  dtbl_entry_t *ent =
+    dispatcher->table[get_message_id("bunch_of_coconuts")];
+  tt_int_op(2, OP_EQ, ent->n_enabled);
+  tt_int_op(2, OP_EQ, ent->n_fns);
+  tt_ptr_op(ent->rcv[0].fn, OP_EQ, recv_fn__bunch_of_coconuts);
+  tt_ptr_op(ent->rcv[1].fn, OP_EQ, recv_fn__bunch_of_coconuts);
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+}
+
+static void
+some_other_coconut_hook(const msg_t *m)
+{
+  (void)m;
+}
+
+/* Subscribe hooks should be build correctly when there are a bunch of
+ * them. */
+static void
+test_pubsub_build_sub_many(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+  pubsub_connector_t *c = NULL;
+  char *sysname = NULL;
+  b = pubsub_builder_new();
+  seed_pubsub_builder_basic(b);
+
+  int i;
+  for (i = 1; i < 100; ++i) {
+    tor_asprintf(&sysname, "system%d",i);
+    c = pubsub_connector_for_subsystem(b, get_subsys_id(sysname));
+    if (i % 7) {
+      DISPATCH_ADD_SUB(c, main, bunch_of_coconuts);
+    } else {
+      pubsub_add_sub_(c, some_other_coconut_hook,
+                      get_channel_id("main"),
+                      get_message_id("bunch_of_coconuts"),
+                      get_msg_type_id("int"),
+                      0 /* flags */,
+                      "somewhere.c", 22);
+    }
+    pubsub_connector_free(c);
+    tor_free(sysname);
+  };
+
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher);
+
+  dtbl_entry_t *ent =
+    dispatcher->table[get_message_id("bunch_of_coconuts")];
+  tt_int_op(100, OP_EQ, ent->n_enabled);
+  tt_int_op(100, OP_EQ, ent->n_fns);
+  tt_ptr_op(ent->rcv[0].fn, OP_EQ, recv_fn__bunch_of_coconuts);
+  tt_ptr_op(ent->rcv[1].fn, OP_EQ, recv_fn__bunch_of_coconuts);
+  tt_ptr_op(ent->rcv[76].fn, OP_EQ, recv_fn__bunch_of_coconuts);
+  tt_ptr_op(ent->rcv[77].fn, OP_EQ, some_other_coconut_hook);
+  tt_ptr_op(ent->rcv[78].fn, OP_EQ, recv_fn__bunch_of_coconuts);
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  tor_free(sysname);
+}
+
+/* The same subsystem can only declare one publish or subscribe. */
+static void
+test_pubsub_build_pubsub_redundant(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+  pubsub_connector_t *c = NULL;
+
+  b = pubsub_builder_new();
+  seed_pubsub_builder_basic(b);
+  pub_binding_t btmp;
+
+  {
+    c = pubsub_connector_for_subsystem(b, get_subsys_id("sys2"));
+    DISPATCH_ADD_SUB(c, main, bunch_of_coconuts);
+    pubsub_add_pub_(c, &btmp, get_channel_id("main"),
+                    get_message_id("yes_we_have_no"),
+                    get_msg_type_id("string"),
+                    0 /* flags */,
+                    "somewhere.c", 22);
+    pubsub_connector_free(c);
+  };
+
+  setup_full_capture_of_logs(LOG_WARN);
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher == NULL);
+
+  expect_log_msg_containing(
+    "Message \"yes_we_have_no\" is configured to be published by "
+    "subsystem \"sys2\" more than once.");
+  expect_log_msg_containing(
+    "Message \"bunch_of_coconuts\" is configured to be subscribed by "
+    "subsystem \"sys2\" more than once.");
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  teardown_capture_of_logs();
+}
+
+/* It's fine to declare the excl flag. */
+static void
+test_pubsub_build_excl_ok(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+
+  b = pubsub_builder_new();
+  // Try one excl/excl pair and one excl/non pair.
+  seed_dispatch_builder(b, DISP_FLAG_EXCL, 0,
+                        DISP_FLAG_EXCL, DISP_FLAG_EXCL);
+
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher);
+
+  // 1 subscribers
+  tt_int_op(1, OP_EQ,
+            dispatcher->table[get_message_id("yes_we_have_no")]->n_enabled);
+  // 1 subscriber.
+  tt_int_op(1, OP_EQ,
+            dispatcher->table[get_message_id("bunch_of_coconuts")]->n_enabled);
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+}
+
+/* but if you declare the excl flag, you need to mean it. */
+static void
+test_pubsub_build_excl_bad(void *arg)
+{
+  (void)arg;
+  pubsub_builder_t *b = NULL;
+  dispatch_t *dispatcher = NULL;
+  pubsub_connector_t *c = NULL;
+
+  b = pubsub_builder_new();
+  seed_dispatch_builder(b, DISP_FLAG_EXCL, DISP_FLAG_EXCL,
+                        0, 0);
+
+  {
+    c = pubsub_connector_for_subsystem(b, get_subsys_id("sys3"));
+    DISPATCH_ADD_PUB_(c, main, bunch_of_coconuts, 0);
+    DISPATCH_ADD_SUB_(c, main, yes_we_have_no, 0);
+    pubsub_connector_free(c);
+  };
+
+  setup_full_capture_of_logs(LOG_WARN);
+  dispatcher = pubsub_builder_finalize(b, NULL);
+  b = NULL;
+  tt_assert(dispatcher == NULL);
+
+  expect_log_msg_containing("has multiple publishers, but at least one is "
+                            "marked as exclusive.");
+  expect_log_msg_containing("has multiple subscribers, but at least one is "
+                            "marked as exclusive.");
+
+ done:
+  pubsub_builder_free(b);
+  dispatch_free(dispatcher);
+  teardown_capture_of_logs();
+}
+
+#define T(name, flags)                                          \
+  { #name, test_pubsub_build_ ## name , (flags), NULL, NULL }
+
+struct testcase_t pubsub_build_tests[] = {
+  T(types_ok, TT_FORK),
+  T(types_decls_conflict, TT_FORK),
+  T(unused_message, TT_FORK),
+  T(missing_pubsub, TT_FORK),
+  T(stub_pubsub, TT_FORK),
+  T(channels_conflict, TT_FORK),
+  T(types_conflict, TT_FORK),
+  T(pubsub_same, TT_FORK),
+  T(pubsub_multi, TT_FORK),
+  T(sub_many, TT_FORK),
+  T(pubsub_redundant, TT_FORK),
+  T(excl_ok, TT_FORK),
+  T(excl_bad, TT_FORK),
+  END_OF_TESTCASES
+};
diff --git a/src/test/test_pubsub_msg.c b/src/test/test_pubsub_msg.c
new file mode 100644
index 000000000..73c7c9f54
--- /dev/null
+++ b/src/test/test_pubsub_msg.c
@@ -0,0 +1,305 @@
+/* Copyright (c) 2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#define DISPATCH_PRIVATE
+
+#include "test/test.h"
+
+#include "lib/dispatch/dispatch.h"
+#include "lib/dispatch/dispatch_naming.h"
+#include "lib/dispatch/dispatch_st.h"
+#include "lib/dispatch/msgtypes.h"
+#include "lib/pubsub/pubsub_flags.h"
+#include "lib/pubsub/pub_binding_st.h"
+#include "lib/pubsub/pubsub_build.h"
+#include "lib/pubsub/pubsub_builder_st.h"
+#include "lib/pubsub/pubsub_connect.h"
+#include "lib/pubsub/pubsub_publish.h"
+
+#include "lib/log/escape.h"
+#include "lib/malloc/malloc.h"
+#include "lib/string/printf.h"
+
+#include <stdio.h>
+#include <string.h>
+
+static char *
+ex_str_fmt(msg_aux_data_t aux)
+{
+  return esc_for_log(aux.ptr);
+}
+static void
+ex_str_free(msg_aux_data_t aux)
+{
+  tor_free_(aux.ptr);
+}
+static dispatch_typefns_t stringfns = {
+  .free_fn = ex_str_free,
+  .fmt_fn = ex_str_fmt
+};
+
+// We're using the lowest-level publish/subscribe logic here, to avoid the
+// pubsub_macros.h macros and just test the dispatch core.  We'll use a string
+// type for everything.
+
+#define DECLARE_MESSAGE(suffix)                         \
+  static pub_binding_t pub_binding_##suffix;            \
+  static int msg_received_##suffix = 0;                 \
+  static void recv_msg_##suffix(const msg_t *m) {       \
+    (void)m;                                            \
+    ++msg_received_##suffix;                            \
+  }                                                     \
+  EAT_SEMICOLON
+
+#define ADD_PUBLISH(binding_suffix, subsys, channel, msg, flags)        \
+  STMT_BEGIN {                                                          \
+    con = pubsub_connector_for_subsystem(builder,                       \
+                                           get_subsys_id(#subsys));     \
+    pubsub_add_pub_(con, &pub_binding_##binding_suffix,                 \
+                      get_channel_id(#channel),                         \
+                      get_message_id(#msg), get_msg_type_id("string"),  \
+                      (flags), __FILE__, __LINE__);                     \
+    pubsub_connector_free(con);                                         \
+  } STMT_END
+
+#define ADD_SUBSCRIBE(hook_suffix, subsys, channel, msg, flags)         \
+  STMT_BEGIN {                                                          \
+    con = pubsub_connector_for_subsystem(builder,                       \
+                                           get_subsys_id(#subsys));     \
+    pubsub_add_sub_(con, recv_msg_##hook_suffix,                        \
+                      get_channel_id(#channel),                         \
+                      get_message_id(#msg), get_msg_type_id("string"),  \
+                      (flags), __FILE__, __LINE__);                     \
+    pubsub_connector_free(con);                                         \
+  } STMT_END
+
+#define SEND(binding_suffix, val)                          \
+  STMT_BEGIN {                                             \
+    msg_aux_data_t data_;                                  \
+    data_.ptr = tor_strdup(val);                           \
+    pubsub_pub_(&pub_binding_##binding_suffix, data_);     \
+  } STMT_END
+
+DECLARE_MESSAGE(msg1);
+DECLARE_MESSAGE(msg2);
+DECLARE_MESSAGE(msg3);
+DECLARE_MESSAGE(msg4);
+DECLARE_MESSAGE(msg5);
+
+static smartlist_t *strings_received = NULL;
+static void
+recv_msg_copy_string(const msg_t *m)
+{
+  const char *s = m->aux_data__.ptr;
+  smartlist_add(strings_received, tor_strdup(s));
+}
+
+static void *
+setup_dispatcher(const struct testcase_t *testcase)
+{
+  (void)testcase;
+  pubsub_builder_t *builder = pubsub_builder_new();
+  pubsub_connector_t *con;
+
+  {
+    con = pubsub_connector_for_subsystem(builder, get_subsys_id("types"));
+    pubsub_connector_register_type_(con,
+                                    get_msg_type_id("string"),
+                                    &stringfns,
+                                    "nowhere.c", 99);
+    pubsub_connector_free(con);
+  }
+  // message1 has one publisher and one subscriber.
+  ADD_PUBLISH(msg1, sys1, main, message1, 0);
+  ADD_SUBSCRIBE(msg1, sys2, main, message1, 0);
+
+  // message2 has a publisher and a stub subscriber.
+  ADD_PUBLISH(msg2, sys1, main, message2, 0);
+  ADD_SUBSCRIBE(msg2, sys2, main, message2, DISP_FLAG_STUB);
+
+  // message3 has a publisher and three subscribers.
+  ADD_PUBLISH(msg3, sys1, main, message3, 0);
+  ADD_SUBSCRIBE(msg3, sys2, main, message3, 0);
+  ADD_SUBSCRIBE(msg3, sys3, main, message3, 0);
+  ADD_SUBSCRIBE(msg3, sys4, main, message3, 0);
+
+  // message4 has one publisher and two subscribers, but it's on another
+  // channel.
+  ADD_PUBLISH(msg4, sys2, other, message4, 0);
+  ADD_SUBSCRIBE(msg4, sys1, other, message4, 0);
+  ADD_SUBSCRIBE(msg4, sys3, other, message4, 0);
+
+  // message5 has a huge number of recipients.
+  ADD_PUBLISH(msg5, sys3, main, message5, 0);
+  ADD_SUBSCRIBE(msg5, sys4, main, message5, 0);
+  ADD_SUBSCRIBE(msg5, sys5, main, message5, 0);
+  ADD_SUBSCRIBE(msg5, sys6, main, message5, 0);
+  ADD_SUBSCRIBE(msg5, sys7, main, message5, 0);
+  ADD_SUBSCRIBE(msg5, sys8, main, message5, 0);
+  for (int i = 0; i < 1000-5; ++i) {
+    char *sys;
+    tor_asprintf(&sys, "xsys-%d", i);
+    con = pubsub_connector_for_subsystem(builder, get_subsys_id(sys));
+    pubsub_add_sub_(con, recv_msg_copy_string,
+                    get_channel_id("main"),
+                    get_message_id("message5"),
+                    get_msg_type_id("string"), 0, "here", 100);
+    pubsub_connector_free(con);
+    tor_free(sys);
+  }
+
+  return pubsub_builder_finalize(builder, NULL);
+}
+
+static int
+cleanup_dispatcher(const struct testcase_t *testcase, void *dispatcher_)
+{
+  (void)testcase;
+  dispatch_t *dispatcher = dispatcher_;
+  dispatch_free(dispatcher);
+  return 1;
+}
+
+static const struct testcase_setup_t dispatcher_setup = {
+  setup_dispatcher, cleanup_dispatcher
+};
+
+static void
+test_pubsub_msg_minimal(void *arg)
+{
+  dispatch_t *d = arg;
+
+  tt_int_op(0, OP_EQ, msg_received_msg1);
+  SEND(msg1, "hello world");
+  tt_int_op(0, OP_EQ, msg_received_msg1); // hasn't actually arrived yet.
+
+  tt_int_op(0, OP_EQ, dispatch_flush(d, get_channel_id("main"), 1000));
+  tt_int_op(1, OP_EQ, msg_received_msg1); // we got the message!
+
+ done:
+  ;
+}
+
+static void
+test_pubsub_msg_send_to_stub(void *arg)
+{
+  dispatch_t *d = arg;
+
+  tt_int_op(0, OP_EQ, msg_received_msg2);
+  SEND(msg2, "hello silence");
+  tt_int_op(0, OP_EQ, msg_received_msg2); // hasn't actually arrived yet.
+
+  tt_int_op(0, OP_EQ, dispatch_flush(d, get_channel_id("main"), 1000));
+  tt_int_op(0, OP_EQ, msg_received_msg2); // doesn't arrive -- stub hook.
+
+ done:
+  ;
+}
+
+static void
+test_pubsub_msg_cancel_msgs(void *arg)
+{
+  dispatch_t *d = arg;
+
+  tt_int_op(0, OP_EQ, msg_received_msg1);
+  for (int i = 0; i < 100; ++i) {
+    SEND(msg1, "hello world");
+  }
+  tt_int_op(0, OP_EQ, msg_received_msg1); // hasn't actually arrived yet.
+
+  tt_int_op(0, OP_EQ, dispatch_flush(d, get_channel_id("main"), 10));
+  tt_int_op(10, OP_EQ, msg_received_msg1); // we got the message 10 times.
+
+  // At this point, the dispatcher will be freed with queued, undelivered
+  // messages.
+ done:
+  ;
+}
+
+struct alertfn_target {
+  dispatch_t *d;
+  channel_id_t ch;
+  int count;
+};
+static void
+alertfn_generic(dispatch_t *d, channel_id_t ch, void *arg)
+{
+  struct alertfn_target *t = arg;
+  tt_ptr_op(d, OP_EQ, t->d);
+  tt_int_op(ch, OP_EQ, t->ch);
+  ++t->count;
+ done:
+  ;
+}
+
+static void
+test_pubsub_msg_alertfns(void *arg)
+{
+  dispatch_t *d = arg;
+  struct alertfn_target ch1_a = { d, get_channel_id("main"), 0 };
+  struct alertfn_target ch2_a = { d, get_channel_id("other"), 0 };
+
+  tt_int_op(0, OP_EQ,
+            dispatch_set_alert_fn(d, get_channel_id("main"),
+                                  alertfn_generic, &ch1_a));
+  tt_int_op(0, OP_EQ,
+            dispatch_set_alert_fn(d, get_channel_id("other"),
+                                  alertfn_generic, &ch2_a));
+
+  SEND(msg3, "hello");
+  tt_int_op(ch1_a.count, OP_EQ, 1);
+  SEND(msg3, "world");
+  tt_int_op(ch1_a.count, OP_EQ, 1); // only the first message sends an alert
+  tt_int_op(ch2_a.count, OP_EQ, 0); // no alert for 'other'
+
+  SEND(msg4, "worse things happen in C");
+  tt_int_op(ch2_a.count, OP_EQ, 1);
+
+  // flush the first (main) channel...
+  tt_int_op(0, OP_EQ, dispatch_flush(d, get_channel_id("main"), 1000));
+  tt_int_op(6, OP_EQ, msg_received_msg3); // 3 subscribers, 2 instances.
+
+  // now that the main channel is flushed, sending another message on it
+  // starts another alert.
+  tt_int_op(ch1_a.count, OP_EQ, 1);
+  SEND(msg1, "plover");
+  tt_int_op(ch1_a.count, OP_EQ, 2);
+  tt_int_op(ch2_a.count, OP_EQ, 1);
+
+ done:
+  ;
+}
+
+/* try more than N_FAST_FNS hooks on msg5 */
+static void
+test_pubsub_msg_many_hooks(void *arg)
+{
+  dispatch_t *d = arg;
+  strings_received = smartlist_new();
+
+  tt_int_op(0, OP_EQ, msg_received_msg5);
+  SEND(msg5, "hello world");
+  tt_int_op(0, OP_EQ, msg_received_msg5);
+  tt_int_op(0, OP_EQ, smartlist_len(strings_received));
+
+  tt_int_op(0, OP_EQ, dispatch_flush(d, get_channel_id("main"), 100000));
+  tt_int_op(5, OP_EQ, msg_received_msg5);
+  tt_int_op(995, OP_EQ, smartlist_len(strings_received));
+
+ done:
+  SMARTLIST_FOREACH(strings_received, char *, s, tor_free(s));
+  smartlist_free(strings_received);
+}
+
+#define T(name)                                                 \
+  { #name, test_pubsub_msg_ ## name , TT_FORK,                \
+      &dispatcher_setup, NULL }
+
+struct testcase_t pubsub_msg_tests[] = {
+  T(minimal),
+  T(send_to_stub),
+  T(cancel_msgs),
+  T(alertfns),
+  T(many_hooks),
+  END_OF_TESTCASES
+};
diff --git a/src/test/test_rebind.sh b/src/test/test_rebind.sh
index ea2012957..e0d8394d3 100755
--- a/src/test/test_rebind.sh
+++ b/src/test/test_rebind.sh
@@ -7,7 +7,7 @@ if test "$UNAME_OS" = 'CYGWIN' || \
    test "$UNAME_OS" = 'MSYS' || \
    test "$UNAME_OS" = 'MINGW'; then
   if test "$APPVEYOR" = 'True'; then
-    echo "This test is disabled on Windows CI, as it requires firewall examptions. Skipping." >&2
+    echo "This test is disabled on Windows CI, as it requires firewall exemptions. Skipping." >&2
     exit 77
   fi
 fi
@@ -15,10 +15,15 @@ fi
 exitcode=0
 
 tmpdir=
-clean () { test -n "$tmpdir" && test -d "$tmpdir" && rm -rf "$tmpdir" || :; }
+clean () {
+  if [ -n "$tmpdir" ] && [ -d "$tmpdir" ]; then
+    rm -rf "$tmpdir"
+  fi
+}
+
 trap clean EXIT HUP INT TERM
 
-tmpdir="`mktemp -d -t tor_rebind_test.XXXXXX`"
+tmpdir="$(mktemp -d -t tor_rebind_test.XXXXXX)"
 if [ -z "$tmpdir" ]; then
   echo >&2 mktemp failed
   exit 2
diff --git a/src/test/test_relaycell.c b/src/test/test_relaycell.c
index 062358351..c65279fb2 100644
--- a/src/test/test_relaycell.c
+++ b/src/test/test_relaycell.c
@@ -17,6 +17,7 @@
 #include "core/or/circuitbuild.h"
 #include "core/or/circuitlist.h"
 #include "core/or/connection_edge.h"
+#include "core/or/sendme.h"
 #include "core/or/relay.h"
 #include "test/test.h"
 #include "test/log_test_helpers.h"
@@ -812,7 +813,11 @@ test_circbw_relay(void *arg)
   ASSERT_UNCOUNTED_BW();
 
   /* Sendme on circuit with non-full window: counted */
-  PACK_CELL(0, RELAY_COMMAND_SENDME, "Data1234");
+  PACK_CELL(0, RELAY_COMMAND_SENDME, "");
+  /* Recording a cell, the window is updated after decryption so off by one in
+   * order to record and then we process it with the proper window. */
+  circ->cpath->package_window = 901;
+  sendme_record_cell_digest_on_circ(TO_CIRCUIT(circ), circ->cpath);
   circ->cpath->package_window = 900;
   connection_edge_process_relay_cell(&cell, TO_CIRCUIT(circ), edgeconn,
                                      circ->cpath);
diff --git a/src/test/test_relaycrypt.c b/src/test/test_relaycrypt.c
index fe6889e52..4bbf07c3e 100644
--- a/src/test/test_relaycrypt.c
+++ b/src/test/test_relaycrypt.c
@@ -3,6 +3,8 @@
  * Copyright (c) 2007-2019, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+#define CRYPT_PATH_PRIVATE
+
 #include "core/or/or.h"
 #include "core/or/circuitbuild.h"
 #define CIRCUITLIST_PRIVATE
@@ -10,7 +12,7 @@
 #include "lib/crypt_ops/crypto_rand.h"
 #include "core/or/relay.h"
 #include "core/crypto/relay_crypto.h"
-
+#include "core/or/crypt_path.h"
 #include "core/or/cell_st.h"
 #include "core/or/or_circuit_st.h"
 #include "core/or/origin_circuit_st.h"
@@ -49,10 +51,10 @@ testing_circuitset_setup(const struct testcase_t *testcase)
   cs->origin_circ->base_.purpose = CIRCUIT_PURPOSE_C_GENERAL;
   for (i=0; i<3; ++i) {
     crypt_path_t *hop = tor_malloc_zero(sizeof(*hop));
-    relay_crypto_init(&hop->crypto, KEY_MATERIAL[i], sizeof(KEY_MATERIAL[i]),
-                      0, 0);
+    relay_crypto_init(&hop->pvt_crypto, KEY_MATERIAL[i],
+                      sizeof(KEY_MATERIAL[i]), 0, 0);
     hop->state = CPATH_STATE_OPEN;
-    onion_append_to_cpath(&cs->origin_circ->cpath, hop);
+    cpath_extend_linked_list(&cs->origin_circ->cpath, hop);
     tt_ptr_op(hop, OP_EQ, cs->origin_circ->cpath->prev);
   }
 
diff --git a/src/test/test_rng.c b/src/test/test_rng.c
index c749de112..dcf08fff1 100644
--- a/src/test/test_rng.c
+++ b/src/test/test_rng.c
@@ -46,7 +46,7 @@ main(int argc, char **argv)
       return 1;
     }
   }
-#endif
+#endif /* 0 */
 
   crypto_fast_rng_t *rng = crypto_fast_rng_new();
   while (1) {
diff --git a/src/test/test_router.c b/src/test/test_router.c
index ea0ee3e84..5477ab51e 100644
--- a/src/test/test_router.c
+++ b/src/test/test_router.c
@@ -100,6 +100,9 @@ test_router_dump_router_to_string_no_bridge_distribution_method(void *arg)
   router = (routerinfo_t*)router_get_my_routerinfo();
   tt_ptr_op(router, !=, NULL);
 
+  /* The real router_get_my_routerinfo() looks up onion_curve25519_pkey using
+   * get_current_curve25519_keypair(), but we don't initialise static data in
+   * this test. */
   router->onion_curve25519_pkey = &ntor_keypair.pubkey;
 
   /* Generate our server descriptor and ensure that the substring
diff --git a/src/test/test_routerkeys.c b/src/test/test_routerkeys.c
index 727fa5660..0c6b53369 100644
--- a/src/test/test_routerkeys.c
+++ b/src/test/test_routerkeys.c
@@ -399,7 +399,7 @@ test_routerkeys_ed_key_init_split(void *arg)
   tt_assert(kp2 != NULL);
   tt_assert(cert == NULL);
   tt_mem_op(&kp1->pubkey, OP_EQ, &kp2->pubkey, sizeof(kp2->pubkey));
-  tt_assert(tor_mem_is_zero((char*)kp2->seckey.seckey,
+  tt_assert(fast_mem_is_zero((char*)kp2->seckey.seckey,
                             sizeof(kp2->seckey.seckey)));
   ed25519_keypair_free(kp2); kp2 = NULL;
 
@@ -409,7 +409,7 @@ test_routerkeys_ed_key_init_split(void *arg)
   tt_assert(kp2 != NULL);
   tt_assert(cert == NULL);
   tt_mem_op(&kp1->pubkey, OP_EQ, &kp2->pubkey, sizeof(kp2->pubkey));
-  tt_assert(tor_mem_is_zero((char*)kp2->seckey.seckey,
+  tt_assert(fast_mem_is_zero((char*)kp2->seckey.seckey,
                             sizeof(kp2->seckey.seckey)));
   ed25519_keypair_free(kp2); kp2 = NULL;
 
@@ -455,11 +455,11 @@ test_routerkeys_ed_keys_init_all(void *arg)
   options->TestingLinkKeySlop = 2*3600;
 
 #ifdef _WIN32
-  mkdir(dir);
-  mkdir(keydir);
+  tt_int_op(0, OP_EQ, mkdir(dir));
+  tt_int_op(0, OP_EQ, mkdir(keydir));
 #else
-  mkdir(dir, 0700);
-  mkdir(keydir, 0700);
+  tt_int_op(0, OP_EQ, mkdir(dir, 0700));
+  tt_int_op(0, OP_EQ, mkdir(keydir, 0700));
 #endif /* defined(_WIN32) */
 
   options->DataDirectory = dir;
diff --git a/src/test/test_routerlist.c b/src/test/test_routerlist.c
index 84ec8cc46..6d596e87e 100644
--- a/src/test/test_routerlist.c
+++ b/src/test/test_routerlist.c
@@ -631,7 +631,7 @@ mock_clock_skew_warning(const connection_t *conn, long apparent_skew,
   (void)conn;
   mock_apparent_skew = apparent_skew;
   tt_int_op(trusted, OP_EQ, 1);
-  tt_int_op(domain, OP_EQ, LD_GENERAL);
+  tt_i64_op(domain, OP_EQ, LD_GENERAL);
   tt_str_op(received, OP_EQ, "microdesc flavor consensus");
   tt_str_op(source, OP_EQ, "CONSENSUS");
  done:
diff --git a/src/test/test_routerset.c b/src/test/test_routerset.c
index c45f0e159..cc73e6c20 100644
--- a/src/test/test_routerset.c
+++ b/src/test/test_routerset.c
@@ -1765,7 +1765,7 @@ NS(node_get_by_nickname)(const char *nickname, unsigned flags)
  * Structural test for routerset_get_all_nodes, when the nodelist has no nodes.
  */
 
-NS_DECL(smartlist_t *, nodelist_get_list, (void));
+NS_DECL(const smartlist_t *, nodelist_get_list, (void));
 
 static smartlist_t *NS(mock_smartlist);
 
@@ -1795,7 +1795,7 @@ NS(test_main)(void *arg)
     ;
 }
 
-smartlist_t *
+const smartlist_t *
 NS(nodelist_get_list)(void)
 {
   CALLED(nodelist_get_list)++;
@@ -1811,7 +1811,7 @@ NS(nodelist_get_list)(void)
  * the running_only flag is set, but the nodes are not running.
  */
 
-NS_DECL(smartlist_t *, nodelist_get_list, (void));
+NS_DECL(const smartlist_t *, nodelist_get_list, (void));
 
 static smartlist_t *NS(mock_smartlist);
 static node_t NS(mock_node);
@@ -1844,7 +1844,7 @@ NS(test_main)(void *arg)
     ;
 }
 
-smartlist_t *
+const smartlist_t *
 NS(nodelist_get_list)(void)
 {
   CALLED(nodelist_get_list)++;
diff --git a/src/test/test_rust.sh b/src/test/test_rust.sh
index 00b3e88d3..804d2ada3 100755
--- a/src/test/test_rust.sh
+++ b/src/test/test_rust.sh
@@ -14,11 +14,12 @@ rustc_host=$(rustc -vV | grep host | sed 's/host: //')
 
 for cargo_toml_dir in "${abs_top_srcdir:-../../..}"/src/rust/*; do
     if [ -e "${cargo_toml_dir}/Cargo.toml" ]; then
+        # shellcheck disable=SC2086
 	cd "${abs_top_builddir:-../../..}/src/rust" && \
 	    CARGO_TARGET_DIR="${abs_top_builddir:-../../..}/src/rust/target" \
-	    "${CARGO:-cargo}" test ${CARGO_ONLINE-"--frozen"} \
+	    "${CARGO:-cargo}" test "${CARGO_ONLINE-'--frozen'}" \
             --features "test_linking_hack" \
-            --target $rustc_host \
+            --target "$rustc_host" \
 	    ${EXTRA_CARGO_OPTIONS} \
 	    --manifest-path "${cargo_toml_dir}/Cargo.toml" || exitcode=1
     fi
diff --git a/src/test/test_sendme.c b/src/test/test_sendme.c
new file mode 100644
index 000000000..eb402232b
--- /dev/null
+++ b/src/test/test_sendme.c
@@ -0,0 +1,365 @@
+/* Copyright (c) 2014-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/* Unit tests for handling different kinds of relay cell */
+
+#define CIRCUITLIST_PRIVATE
+#define NETWORKSTATUS_PRIVATE
+#define SENDME_PRIVATE
+#define RELAY_PRIVATE
+
+#include "core/or/circuit_st.h"
+#include "core/or/or_circuit_st.h"
+#include "core/or/origin_circuit_st.h"
+#include "core/or/circuitlist.h"
+#include "core/or/relay.h"
+#include "core/or/sendme.h"
+
+#include "feature/nodelist/networkstatus.h"
+#include "feature/nodelist/networkstatus_st.h"
+
+#include "lib/crypt_ops/crypto_digest.h"
+
+#include "test/test.h"
+#include "test/log_test_helpers.h"
+
+static void
+setup_mock_consensus(void)
+{
+  current_md_consensus = current_ns_consensus =
+    tor_malloc_zero(sizeof(networkstatus_t));
+  current_md_consensus->net_params = smartlist_new();
+  current_md_consensus->routerstatus_list = smartlist_new();
+}
+
+static void
+free_mock_consensus(void)
+{
+  SMARTLIST_FOREACH(current_md_consensus->routerstatus_list, void *, r,
+                    tor_free(r));
+  smartlist_free(current_md_consensus->routerstatus_list);
+  smartlist_free(current_ns_consensus->net_params);
+  tor_free(current_ns_consensus);
+}
+
+static void
+test_v1_record_digest(void *arg)
+{
+  or_circuit_t *or_circ = NULL;
+  circuit_t *circ = NULL;
+
+  (void) arg;
+
+  /* Create our dummy circuit. */
+  or_circ = or_circuit_new(1, NULL);
+  /* Points it to the OR circuit now. */
+  circ = TO_CIRCUIT(or_circ);
+
+  /* The package window has to be a multiple of CIRCWINDOW_INCREMENT minus 1
+   * in order to catched the CIRCWINDOW_INCREMENT-nth cell. Try something that
+   * shouldn't be noted. */
+  circ->package_window = CIRCWINDOW_INCREMENT;
+  sendme_record_cell_digest_on_circ(circ, NULL);
+  tt_assert(!circ->sendme_last_digests);
+
+  /* This should work now. Package window at CIRCWINDOW_INCREMENT + 1. */
+  circ->package_window++;
+  sendme_record_cell_digest_on_circ(circ, NULL);
+  tt_assert(circ->sendme_last_digests);
+  tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 1);
+
+  /* Next cell in the package window shouldn't do anything. */
+  circ->package_window++;
+  sendme_record_cell_digest_on_circ(circ, NULL);
+  tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 1);
+
+  /* The next CIRCWINDOW_INCREMENT should add one more digest. */
+  circ->package_window = (CIRCWINDOW_INCREMENT * 2) + 1;
+  sendme_record_cell_digest_on_circ(circ, NULL);
+  tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 2);
+
+ done:
+  circuit_free_(circ);
+}
+
+static void
+test_v1_consensus_params(void *arg)
+{
+  (void) arg;
+
+  setup_mock_consensus();
+  tt_assert(current_md_consensus);
+
+  /* Both zeroes. */
+  smartlist_add(current_md_consensus->net_params,
+                (void *) "sendme_emit_min_version=0");
+  smartlist_add(current_md_consensus->net_params,
+                (void *) "sendme_accept_min_version=0");
+  tt_int_op(get_emit_min_version(), OP_EQ, 0);
+  tt_int_op(get_accept_min_version(), OP_EQ, 0);
+  smartlist_clear(current_md_consensus->net_params);
+
+  /* Both ones. */
+  smartlist_add(current_md_consensus->net_params,
+                (void *) "sendme_emit_min_version=1");
+  smartlist_add(current_md_consensus->net_params,
+                (void *) "sendme_accept_min_version=1");
+  tt_int_op(get_emit_min_version(), OP_EQ, 1);
+  tt_int_op(get_accept_min_version(), OP_EQ, 1);
+  smartlist_clear(current_md_consensus->net_params);
+
+  /* Different values from each other. */
+  smartlist_add(current_md_consensus->net_params,
+                (void *) "sendme_emit_min_version=1");
+  smartlist_add(current_md_consensus->net_params,
+                (void *) "sendme_accept_min_version=0");
+  tt_int_op(get_emit_min_version(), OP_EQ, 1);
+  tt_int_op(get_accept_min_version(), OP_EQ, 0);
+  smartlist_clear(current_md_consensus->net_params);
+
+  /* Validate is the cell version is coherent with our internal default value
+   * and the one in the consensus. */
+  smartlist_add(current_md_consensus->net_params,
+                (void *) "sendme_accept_min_version=1");
+  /* Minimum acceptable value is 1. */
+  tt_int_op(cell_version_can_be_handled(1), OP_EQ, true);
+  /* Minimum acceptable value is 1 so a cell version of 0 is refused. */
+  tt_int_op(cell_version_can_be_handled(0), OP_EQ, false);
+
+ done:
+  free_mock_consensus();
+}
+
+static void
+test_v1_build_cell(void *arg)
+{
+  uint8_t payload[RELAY_PAYLOAD_SIZE], digest[DIGEST_LEN];
+  ssize_t ret;
+  crypto_digest_t *cell_digest = NULL;
+  or_circuit_t *or_circ = NULL;
+  circuit_t *circ = NULL;
+
+  (void) arg;
+
+  or_circ = or_circuit_new(1, NULL);
+  circ = TO_CIRCUIT(or_circ);
+  circ->sendme_last_digests = smartlist_new();
+
+  cell_digest = crypto_digest_new();
+  tt_assert(cell_digest);
+  crypto_digest_add_bytes(cell_digest, "AAAAAAAAAAAAAAAAAAAA", 20);
+  crypto_digest_get_digest(cell_digest, (char *) digest, sizeof(digest));
+  smartlist_add(circ->sendme_last_digests, tor_memdup(digest, sizeof(digest)));
+
+  /* SENDME v1 payload is 3 bytes + 20 bytes digest. See spec. */
+  ret = build_cell_payload_v1(digest, payload);
+  tt_int_op(ret, OP_EQ, 23);
+
+  /* Validation. */
+
+  /* An empty payload means SENDME version 0 thus valid. */
+  tt_int_op(sendme_is_valid(circ, payload, 0), OP_EQ, true);
+  /* Current phoney digest should have been popped. */
+  tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 0);
+
+  /* An unparseable cell means invalid. */
+  setup_full_capture_of_logs(LOG_INFO);
+  tt_int_op(sendme_is_valid(circ, (const uint8_t *) "A", 1), OP_EQ, false);
+  expect_log_msg_containing("Unparseable SENDME cell received. "
+                            "Closing circuit.");
+  teardown_capture_of_logs();
+
+  /* No cell digest recorded for this. */
+  setup_full_capture_of_logs(LOG_INFO);
+  tt_int_op(sendme_is_valid(circ, payload, sizeof(payload)), OP_EQ, false);
+  expect_log_msg_containing("We received a SENDME but we have no cell digests "
+                            "to match. Closing circuit.");
+  teardown_capture_of_logs();
+
+  /* Note the wrong digest in the circuit, cell should fail validation. */
+  circ->package_window = CIRCWINDOW_INCREMENT + 1;
+  sendme_record_cell_digest_on_circ(circ, NULL);
+  tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 1);
+  setup_full_capture_of_logs(LOG_INFO);
+  tt_int_op(sendme_is_valid(circ, payload, sizeof(payload)), OP_EQ, false);
+  /* After a validation, the last digests is always popped out. */
+  tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 0);
+  expect_log_msg_containing("SENDME v1 cell digest do not match.");
+  teardown_capture_of_logs();
+
+  /* Record the cell digest into the circuit, cell should validate. */
+  memcpy(or_circ->crypto.sendme_digest, digest, sizeof(digest));
+  circ->package_window = CIRCWINDOW_INCREMENT + 1;
+  sendme_record_cell_digest_on_circ(circ, NULL);
+  tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 1);
+  tt_int_op(sendme_is_valid(circ, payload, sizeof(payload)), OP_EQ, true);
+  /* After a validation, the last digests is always popped out. */
+  tt_int_op(smartlist_len(circ->sendme_last_digests), OP_EQ, 0);
+
+ done:
+  crypto_digest_free(cell_digest);
+  circuit_free_(circ);
+}
+
+static void
+test_cell_payload_pad(void *arg)
+{
+  size_t pad_offset, payload_len, expected_offset;
+
+  (void) arg;
+
+  /* Offset should be 0, not enough room for padding. */
+  payload_len = RELAY_PAYLOAD_SIZE;
+  pad_offset = get_pad_cell_offset(payload_len);
+  tt_int_op(pad_offset, OP_EQ, 0);
+  tt_int_op(CELL_PAYLOAD_SIZE - pad_offset, OP_LE, CELL_PAYLOAD_SIZE);
+
+  /* Still no room because we keep 4 extra bytes. */
+  pad_offset = get_pad_cell_offset(payload_len - 4);
+  tt_int_op(pad_offset, OP_EQ, 0);
+  tt_int_op(CELL_PAYLOAD_SIZE - pad_offset, OP_LE, CELL_PAYLOAD_SIZE);
+
+  /* We should have 1 byte of padding. Meaning, the offset should be the
+   * CELL_PAYLOAD_SIZE minus 1 byte. */
+  expected_offset = CELL_PAYLOAD_SIZE - 1;
+  pad_offset = get_pad_cell_offset(payload_len - 5);
+  tt_int_op(pad_offset, OP_EQ, expected_offset);
+  tt_int_op(CELL_PAYLOAD_SIZE - pad_offset, OP_LE, CELL_PAYLOAD_SIZE);
+
+  /* Now some arbitrary small payload length. The cell size is header + 10 +
+   * extra 4 bytes we keep so the offset should be there. */
+  expected_offset = RELAY_HEADER_SIZE + 10 + 4;
+  pad_offset = get_pad_cell_offset(10);
+  tt_int_op(pad_offset, OP_EQ, expected_offset);
+  tt_int_op(CELL_PAYLOAD_SIZE - pad_offset, OP_LE, CELL_PAYLOAD_SIZE);
+
+  /* Data length of 0. */
+  expected_offset = RELAY_HEADER_SIZE + 4;
+  pad_offset = get_pad_cell_offset(0);
+  tt_int_op(pad_offset, OP_EQ, expected_offset);
+  tt_int_op(CELL_PAYLOAD_SIZE - pad_offset, OP_LE, CELL_PAYLOAD_SIZE);
+
+ done:
+  ;
+}
+
+static void
+test_cell_version_validation(void *arg)
+{
+  (void) arg;
+
+  /* We currently only support up to SENDME_MAX_SUPPORTED_VERSION so we are
+   * going to test the boundaries there. */
+
+  tt_assert(cell_version_can_be_handled(SENDME_MAX_SUPPORTED_VERSION));
+
+  /* Version below our supported should pass. */
+  tt_assert(cell_version_can_be_handled(SENDME_MAX_SUPPORTED_VERSION - 1));
+
+  /* Extra version from our supported should fail. */
+  tt_assert(!cell_version_can_be_handled(SENDME_MAX_SUPPORTED_VERSION + 1));
+
+  /* Simple check for version 0. */
+  tt_assert(cell_version_can_be_handled(0));
+
+  /* We MUST handle the default cell version that we emit or accept. */
+  tt_assert(cell_version_can_be_handled(SENDME_EMIT_MIN_VERSION_DEFAULT));
+  tt_assert(cell_version_can_be_handled(SENDME_ACCEPT_MIN_VERSION_DEFAULT));
+
+ done:
+  ;
+}
+
+/* check our decisions about how much stuff to put into relay cells. */
+static void
+test_package_payload_len(void *arg)
+{
+  (void)arg;
+  /* this is not a real circuit: it only has the fields needed for this
+   * test. */
+  circuit_t *c = tor_malloc_zero(sizeof(circuit_t));
+
+  /* check initial conditions. */
+  circuit_reset_sendme_randomness(c);
+  tt_assert(! c->have_sent_sufficiently_random_cell);
+  tt_int_op(c->send_randomness_after_n_cells, OP_GE, CIRCWINDOW_INCREMENT / 2);
+  tt_int_op(c->send_randomness_after_n_cells, OP_LT, CIRCWINDOW_INCREMENT);
+
+  /* We have a bunch of cells before we need to send randomness, so the first
+   * few can be packaged full. */
+  int initial = c->send_randomness_after_n_cells;
+  size_t n = connection_edge_get_inbuf_bytes_to_package(10000, 0, c);
+  tt_uint_op(RELAY_PAYLOAD_SIZE, OP_EQ, n);
+  n = connection_edge_get_inbuf_bytes_to_package(95000, 1, c);
+  tt_uint_op(RELAY_PAYLOAD_SIZE, OP_EQ, n);
+  tt_int_op(c->send_randomness_after_n_cells, OP_EQ, initial - 2);
+
+  /* If package_partial isn't set, we won't package a partially full cell at
+   * all. */
+  n = connection_edge_get_inbuf_bytes_to_package(RELAY_PAYLOAD_SIZE-1, 0, c);
+  tt_int_op(n, OP_EQ, 0);
+  /* no change in our state, since nothing was sent. */
+  tt_assert(! c->have_sent_sufficiently_random_cell);
+  tt_int_op(c->send_randomness_after_n_cells, OP_EQ, initial - 2);
+
+  /* If package_partial is set and the partial cell is not going to have
+   * _enough_ randomness, we package it, but we don't consider ourselves to
+   * have sent a sufficiently random cell. */
+  n = connection_edge_get_inbuf_bytes_to_package(RELAY_PAYLOAD_SIZE-1, 1, c);
+  tt_int_op(n, OP_EQ, RELAY_PAYLOAD_SIZE-1);
+  tt_assert(! c->have_sent_sufficiently_random_cell);
+  tt_int_op(c->send_randomness_after_n_cells, OP_EQ, initial - 3);
+
+  /* Make sure we set have_set_sufficiently_random_cell as appropriate. */
+  n = connection_edge_get_inbuf_bytes_to_package(RELAY_PAYLOAD_SIZE-64, 1, c);
+  tt_int_op(n, OP_EQ, RELAY_PAYLOAD_SIZE-64);
+  tt_assert(c->have_sent_sufficiently_random_cell);
+  tt_int_op(c->send_randomness_after_n_cells, OP_EQ, initial - 4);
+
+  /* Now let's look at what happens when we get down to zero. Since we have
+   * sent a sufficiently random cell, we will not force this one to have a gap.
+   */
+  c->send_randomness_after_n_cells = 0;
+  n = connection_edge_get_inbuf_bytes_to_package(10000, 1, c);
+  tt_int_op(n, OP_EQ, RELAY_PAYLOAD_SIZE);
+  /* Now these will be reset. */
+  tt_assert(! c->have_sent_sufficiently_random_cell);
+  tt_int_op(c->send_randomness_after_n_cells, OP_GE,
+            CIRCWINDOW_INCREMENT / 2 - 1);
+
+  /* What would happen if we hadn't sent a sufficiently random cell? */
+  c->send_randomness_after_n_cells = 0;
+  n = connection_edge_get_inbuf_bytes_to_package(10000, 1, c);
+  const size_t reduced_payload_size = RELAY_PAYLOAD_SIZE - 4 - 16;
+  tt_int_op(n, OP_EQ, reduced_payload_size);
+  /* Now these will be reset. */
+  tt_assert(! c->have_sent_sufficiently_random_cell);
+  tt_int_op(c->send_randomness_after_n_cells, OP_GE,
+            CIRCWINDOW_INCREMENT / 2 - 1);
+
+  /* Here is a fun case: if it's time to package a small cell, then
+   * package_partial==0 should mean we accept that many bytes.
+   */
+  c->send_randomness_after_n_cells = 0;
+  n = connection_edge_get_inbuf_bytes_to_package(reduced_payload_size, 0, c);
+  tt_int_op(n, OP_EQ, reduced_payload_size);
+
+ done:
+  tor_free(c);
+}
+
+struct testcase_t sendme_tests[] = {
+  { "v1_record_digest", test_v1_record_digest, TT_FORK,
+    NULL, NULL },
+  { "v1_consensus_params", test_v1_consensus_params, TT_FORK,
+    NULL, NULL },
+  { "v1_build_cell", test_v1_build_cell, TT_FORK,
+    NULL, NULL },
+  { "cell_payload_pad", test_cell_payload_pad, TT_FORK,
+    NULL, NULL },
+  { "cell_version_validation", test_cell_version_validation, TT_FORK,
+    NULL, NULL },
+  { "package_payload_len", test_package_payload_len, 0, NULL, NULL },
+
+  END_OF_TESTCASES
+};
diff --git a/src/test/test_shared_random.c b/src/test/test_shared_random.c
index 5fa7e80d0..9c8703fa6 100644
--- a/src/test/test_shared_random.c
+++ b/src/test/test_shared_random.c
@@ -449,12 +449,12 @@ test_sr_commit(void *arg)
     /* We should have a reveal value. */
     tt_assert(commit_has_reveal_value(our_commit));
     /* We should have a random value. */
-    tt_assert(!tor_mem_is_zero((char *) our_commit->random_number,
+    tt_assert(!fast_mem_is_zero((char *) our_commit->random_number,
                                sizeof(our_commit->random_number)));
     /* Commit and reveal timestamp should be the same. */
     tt_u64_op(our_commit->commit_ts, OP_EQ, our_commit->reveal_ts);
     /* We should have a hashed reveal. */
-    tt_assert(!tor_mem_is_zero(our_commit->hashed_reveal,
+    tt_assert(!fast_mem_is_zero(our_commit->hashed_reveal,
                                sizeof(our_commit->hashed_reveal)));
     /* Do we have a valid encoded commit and reveal. Note the following only
      * tests if the generated values are correct. Their could be a bug in
@@ -1081,70 +1081,85 @@ test_sr_get_majority_srv_from_votes(void *arg)
   smartlist_free(votes);
 }
 
-/* Test utils that don't depend on authority state */
+/* Testing sr_srv_dup(). */
 static void
-test_utils_general(void *arg)
+test_sr_svr_dup(void *arg)
 {
-  (void) arg;
+  (void)arg;
 
-  /* Testing sr_srv_dup(). */
-  {
-    sr_srv_t *srv = NULL, *dup_srv = NULL;
-    const char *srv_value =
-      "1BDB7C3E973936E4D13A49F37C859B3DC69C429334CF9412E3FEF6399C52D47A";
-    srv = tor_malloc_zero(sizeof(*srv));
-    srv->num_reveals = 42;
-    memcpy(srv->value, srv_value, sizeof(srv->value));
-    dup_srv = sr_srv_dup(srv);
-    tt_assert(dup_srv);
-    tt_u64_op(dup_srv->num_reveals, OP_EQ, srv->num_reveals);
-    tt_mem_op(dup_srv->value, OP_EQ, srv->value, sizeof(srv->value));
-    tor_free(srv);
-    tor_free(dup_srv);
-  }
+  sr_srv_t *srv = NULL, *dup_srv = NULL;
+  const char *srv_value =
+    "1BDB7C3E973936E4D13A49F37C859B3DC69C429334CF9412E3FEF6399C52D47A";
+  srv = tor_malloc_zero(sizeof(*srv));
+  srv->num_reveals = 42;
+  memcpy(srv->value, srv_value, sizeof(srv->value));
+  dup_srv = sr_srv_dup(srv);
+  tt_assert(dup_srv);
+  tt_u64_op(dup_srv->num_reveals, OP_EQ, srv->num_reveals);
+  tt_mem_op(dup_srv->value, OP_EQ, srv->value, sizeof(srv->value));
 
-  /* Testing commitments_are_the_same(). Currently, the check is to test the
-   * value of the encoded commit so let's make sure that actually works. */
-  {
-    /* Payload of 57 bytes that is the length of sr_commit_t->encoded_commit.
-     * 56 bytes of payload and a NUL terminated byte at the end ('\x00')
-     * which comes down to SR_COMMIT_BASE64_LEN + 1. */
-    const char *payload =
-      "\x5d\xb9\x60\xb6\xcc\x51\x68\x52\x31\xd9\x88\x88\x71\x71\xe0\x30"
-      "\x59\x55\x7f\xcd\x61\xc0\x4b\x05\xb8\xcd\xc1\x48\xe9\xcd\x16\x1f"
-      "\x70\x15\x0c\xfc\xd3\x1a\x75\xd0\x93\x6c\xc4\xe0\x5c\xbe\xe2\x18"
-      "\xc7\xaf\x72\xb6\x7c\x9b\x52\x00";
-    sr_commit_t commit1, commit2;
-    memcpy(commit1.encoded_commit, payload, sizeof(commit1.encoded_commit));
-    memcpy(commit2.encoded_commit, payload, sizeof(commit2.encoded_commit));
-    tt_int_op(commitments_are_the_same(&commit1, &commit2), OP_EQ, 1);
-    /* Let's corrupt one of them. */
-    memset(commit1.encoded_commit, 'A', sizeof(commit1.encoded_commit));
-    tt_int_op(commitments_are_the_same(&commit1, &commit2), OP_EQ, 0);
-  }
+ done:
+  tor_free(srv);
+  tor_free(dup_srv);
+}
 
-  /* Testing commit_is_authoritative(). */
-  {
-    crypto_pk_t *k = crypto_pk_new();
-    char digest[DIGEST_LEN];
-    sr_commit_t commit;
+/* Testing commitments_are_the_same(). Currently, the check is to test the
+ * value of the encoded commit so let's make sure that actually works. */
+static void
+test_commitments_are_the_same(void *arg)
+{
+  (void)arg;
 
-    tt_assert(!crypto_pk_generate_key(k));
+  /* Payload of 57 bytes that is the length of sr_commit_t->encoded_commit.
+  * 56 bytes of payload and a NUL terminated byte at the end ('\x00')
+  * which comes down to SR_COMMIT_BASE64_LEN + 1. */
+  const char *payload =
+  "\x5d\xb9\x60\xb6\xcc\x51\x68\x52\x31\xd9\x88\x88\x71\x71\xe0\x30"
+  "\x59\x55\x7f\xcd\x61\xc0\x4b\x05\xb8\xcd\xc1\x48\xe9\xcd\x16\x1f"
+  "\x70\x15\x0c\xfc\xd3\x1a\x75\xd0\x93\x6c\xc4\xe0\x5c\xbe\xe2\x18"
+  "\xc7\xaf\x72\xb6\x7c\x9b\x52\x00";
+  sr_commit_t commit1, commit2;
+  memcpy(commit1.encoded_commit, payload, sizeof(commit1.encoded_commit));
+  memcpy(commit2.encoded_commit, payload, sizeof(commit2.encoded_commit));
+  tt_int_op(commitments_are_the_same(&commit1, &commit2), OP_EQ, 1);
+  /* Let's corrupt one of them. */
+  memset(commit1.encoded_commit, 'A', sizeof(commit1.encoded_commit));
+  tt_int_op(commitments_are_the_same(&commit1, &commit2), OP_EQ, 0);
 
-    tt_int_op(0, OP_EQ, crypto_pk_get_digest(k, digest));
-    memcpy(commit.rsa_identity, digest, sizeof(commit.rsa_identity));
-    tt_int_op(commit_is_authoritative(&commit, digest), OP_EQ, 1);
-    /* Change the pubkey. */
-    memset(commit.rsa_identity, 0, sizeof(commit.rsa_identity));
-    tt_int_op(commit_is_authoritative(&commit, digest), OP_EQ, 0);
-    crypto_pk_free(k);
-  }
+ done:
+  return;
+}
 
-  /* Testing get_phase_str(). */
-  {
-    tt_str_op(get_phase_str(SR_PHASE_REVEAL), OP_EQ, "reveal");
-    tt_str_op(get_phase_str(SR_PHASE_COMMIT), OP_EQ, "commit");
-  }
+/* Testing commit_is_authoritative(). */
+static void
+test_commit_is_authoritative(void *arg)
+{
+  (void)arg;
+
+  crypto_pk_t *k = crypto_pk_new();
+  char digest[DIGEST_LEN];
+  sr_commit_t commit;
+
+  tt_assert(!crypto_pk_generate_key(k));
+
+  tt_int_op(0, OP_EQ, crypto_pk_get_digest(k, digest));
+  memcpy(commit.rsa_identity, digest, sizeof(commit.rsa_identity));
+  tt_int_op(commit_is_authoritative(&commit, digest), OP_EQ, 1);
+  /* Change the pubkey. */
+  memset(commit.rsa_identity, 0, sizeof(commit.rsa_identity));
+  tt_int_op(commit_is_authoritative(&commit, digest), OP_EQ, 0);
+
+ done:
+  crypto_pk_free(k);
+}
+
+static void
+test_get_phase_str(void *arg)
+{
+  (void)arg;
+
+  tt_str_op(get_phase_str(SR_PHASE_REVEAL), OP_EQ, "reveal");
+  tt_str_op(get_phase_str(SR_PHASE_COMMIT), OP_EQ, "commit");
 
  done:
   return;
@@ -1352,7 +1367,7 @@ test_utils_auth(void *arg)
     sr_state_set_current_srv(sr_state_get_current_srv());
     sr_state_set_previous_srv(sr_state_get_previous_srv());
   }
-#endif
+#endif /* 0 */
 
  done:
   sr_state_free_all();
@@ -1649,7 +1664,12 @@ struct testcase_t sr_tests[] = {
   { "sr_compute_srv", test_sr_compute_srv, TT_FORK, NULL, NULL },
   { "sr_get_majority_srv_from_votes", test_sr_get_majority_srv_from_votes,
     TT_FORK, NULL, NULL },
-  { "utils_general", test_utils_general, TT_FORK, NULL, NULL },
+  { "sr_svr_dup", test_sr_svr_dup, TT_FORK, NULL, NULL },
+  { "commitments_are_the_same", test_commitments_are_the_same, TT_FORK, NULL,
+    NULL },
+  { "commit_is_authoritative", test_commit_is_authoritative, TT_FORK, NULL,
+    NULL },
+  { "get_phase_str", test_get_phase_str, TT_FORK, NULL, NULL },
   { "utils_auth", test_utils_auth, TT_FORK, NULL, NULL },
   { "state_transition", test_state_transition, TT_FORK, NULL, NULL },
   { "state_update", test_state_update, TT_FORK,
diff --git a/src/test/test_slow.c b/src/test/test_slow.c
index c3e7edd40..d4d5b755a 100644
--- a/src/test/test_slow.c
+++ b/src/test/test_slow.c
@@ -22,6 +22,7 @@ struct testgroup_t testgroups[] = {
   { "slow/crypto/", slow_crypto_tests },
   { "slow/process/", slow_process_tests },
   { "slow/prob_distr/", slow_stochastic_prob_distr_tests },
+  { "slow/ptr/", slow_ptr_tests },
   END_OF_GROUPS
 };
 
diff --git a/src/test/test_status.c b/src/test/test_status.c
index 9c4746997..2fb2a7b24 100644
--- a/src/test/test_status.c
+++ b/src/test/test_status.c
@@ -404,7 +404,7 @@ NS(logv)(int severity, log_domain_mask_t domain,
   {
     case 0:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "log_heartbeat"), OP_NE, NULL);
       tt_ptr_op(suffix, OP_EQ, NULL);
       tt_str_op(format, OP_EQ,
@@ -412,7 +412,7 @@ NS(logv)(int severity, log_domain_mask_t domain,
       break;
     case 1:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "log_heartbeat"), OP_NE, NULL);
       tt_ptr_op(suffix, OP_EQ, NULL);
       tt_str_op(format, OP_EQ,
@@ -429,7 +429,7 @@ NS(logv)(int severity, log_domain_mask_t domain,
       break;
     case 3:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "rep_hist_log_circuit_handshake_stats"),
                 OP_NE, NULL);
       tt_ptr_op(suffix, OP_EQ, NULL);
@@ -442,13 +442,13 @@ NS(logv)(int severity, log_domain_mask_t domain,
       break;
     case 4:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "rep_hist_log_link_protocol_counts"),
                 OP_NE, NULL);
       break;
     case 5:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_str_op(format, OP_EQ, "DoS mitigation since startup:%s%s%s%s");
       tt_str_op(va_arg(ap, char *), OP_EQ,
                 " 0 circuits killed with too many cells.");
@@ -574,7 +574,7 @@ NS(logv)(int severity, log_domain_mask_t domain, const char *funcname,
   ++NS(n_msgs);
 
   tt_int_op(severity, OP_EQ, LOG_NOTICE);
-  tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+  tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
   tt_ptr_op(strstr(funcname, "log_heartbeat"), OP_NE, NULL);
   tt_ptr_op(suffix, OP_EQ, NULL);
   tt_str_op(format, OP_EQ,
@@ -709,7 +709,7 @@ NS(logv)(int severity, log_domain_mask_t domain,
   {
     case 0:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "log_heartbeat"), OP_NE, NULL);
       tt_ptr_op(suffix, OP_EQ, NULL);
       tt_str_op(format, OP_EQ,
@@ -723,7 +723,7 @@ NS(logv)(int severity, log_domain_mask_t domain,
       break;
     case 1:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "log_accounting"), OP_NE, NULL);
       tt_ptr_op(suffix, OP_EQ, NULL);
       tt_str_op(format, OP_EQ,
@@ -889,7 +889,7 @@ NS(logv)(int severity, log_domain_mask_t domain, const char *funcname,
   {
     case 0:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "log_heartbeat"), OP_NE, NULL);
       tt_ptr_op(suffix, OP_EQ, NULL);
       tt_str_op(format, OP_EQ,
@@ -903,7 +903,7 @@ NS(logv)(int severity, log_domain_mask_t domain, const char *funcname,
       break;
     case 1:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "log_heartbeat"), OP_NE, NULL);
       tt_ptr_op(suffix, OP_EQ, NULL);
       tt_str_op(format, OP_EQ,
@@ -1038,7 +1038,7 @@ NS(logv)(int severity, log_domain_mask_t domain,
   {
     case 0:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "log_heartbeat"), OP_NE, NULL);
       tt_ptr_op(suffix, OP_EQ, NULL);
       tt_str_op(format, OP_EQ,
@@ -1052,7 +1052,7 @@ NS(logv)(int severity, log_domain_mask_t domain,
       break;
     case 1:
       tt_int_op(severity, OP_EQ, LOG_NOTICE);
-      tt_int_op(domain, OP_EQ, LD_HEARTBEAT);
+      tt_u64_op(domain, OP_EQ, LD_HEARTBEAT);
       tt_ptr_op(strstr(funcname, "log_heartbeat"), OP_NE, NULL);
       tt_ptr_op(suffix, OP_EQ, NULL);
       tt_str_op(format, OP_EQ,
diff --git a/src/test/test_switch_id.sh b/src/test/test_switch_id.sh
index 79c44f2eb..b13bf7602 100755
--- a/src/test/test_switch_id.sh
+++ b/src/test/test_switch_id.sh
@@ -1,11 +1,11 @@
 #!/bin/sh
 
-if test "`id -u`" != '0'; then
+if test "$(id -u)" != '0'; then
     echo "This test only works when run as root. Skipping." >&2
     exit 77
 fi
 
-if test "`id -u nobody`" = ""; then
+if test "$(id -u nobody)" = ""; then
     echo "This test requires that your system have a 'nobody' user. Sorry." >&2
     exit 1
 fi
diff --git a/src/test/test_tortls.c b/src/test/test_tortls.c
index 11e35be2f..5f87434f6 100644
--- a/src/test/test_tortls.c
+++ b/src/test/test_tortls.c
@@ -219,7 +219,7 @@ test_tortls_tor_tls_get_error(void *data)
   crypto_pk_free(key2);
   tor_tls_free(tls);
 }
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 static void
 test_tortls_x509_cert_get_id_digests(void *ignored)
@@ -336,7 +336,7 @@ test_tortls_server_got_renegotiate(void *ignored)
  done:
   tor_free(tls);
 }
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 static void
 test_tortls_evaluate_ecgroup_for_tls(void *ignored)
@@ -526,7 +526,7 @@ struct testcase_t tortls_tests[] = {
   LOCAL_TEST_CASE(get_forced_write_size, 0),
   LOCAL_TEST_CASE(used_v1_handshake, TT_FORK),
   LOCAL_TEST_CASE(server_got_renegotiate, 0),
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
   LOCAL_TEST_CASE(evaluate_ecgroup_for_tls, 0),
   LOCAL_TEST_CASE(double_init, TT_FORK),
   LOCAL_TEST_CASE(address, TT_FORK),
diff --git a/src/test/test_tortls.h b/src/test/test_tortls.h
index 1a8b117d0..4567b9f6a 100644
--- a/src/test/test_tortls.h
+++ b/src/test/test_tortls.h
@@ -10,4 +10,4 @@ extern const char *notCompletelyValidCertString;
 extern const char *validCertString;
 extern const char *caCertString;
 
-#endif
+#endif /* !defined(TEST_TORTLS_H) */
diff --git a/src/test/test_tortls_openssl.c b/src/test/test_tortls_openssl.c
index 73041a871..81e2d3aa4 100644
--- a/src/test/test_tortls_openssl.c
+++ b/src/test/test_tortls_openssl.c
@@ -133,7 +133,7 @@ library_init(void)
 #else
   SSL_library_init();
   SSL_load_error_strings();
-#endif
+#endif /* defined(OPENSSL_1_1_API) */
 }
 
 static void
@@ -477,7 +477,7 @@ fake_x509_free(X509 *cert)
     tor_free(cert);
   }
 }
-#endif
+#endif /* !defined(OPENSSL_OPAQUE) */
 
 static tor_x509_cert_t *fixed_x509_cert = NULL;
 static tor_x509_cert_t *
diff --git a/src/test/test_util.c b/src/test/test_util.c
index f1ffae7af..2faadd4e1 100644
--- a/src/test/test_util.c
+++ b/src/test/test_util.c
@@ -6,7 +6,6 @@
 #include "orconfig.h"
 #define COMPAT_PRIVATE
 #define COMPAT_TIME_PRIVATE
-#define CONTROL_PRIVATE
 #define UTIL_PRIVATE
 #define UTIL_MALLOC_PRIVATE
 #define SOCKET_PRIVATE
@@ -16,6 +15,7 @@
 #include "lib/buf/buffers.h"
 #include "app/config/config.h"
 #include "feature/control/control.h"
+#include "feature/control/control_proto.h"
 #include "feature/client/transports.h"
 #include "lib/crypt_ops/crypto_format.h"
 #include "lib/crypt_ops/crypto_rand.h"
@@ -2087,14 +2087,14 @@ test_util_strmisc(void *arg)
   /* Test mem_is_zero */
   memset(buf,0,128);
   buf[128] = 'x';
-  tt_assert(tor_mem_is_zero(buf, 10));
-  tt_assert(tor_mem_is_zero(buf, 20));
-  tt_assert(tor_mem_is_zero(buf, 128));
-  tt_assert(!tor_mem_is_zero(buf, 129));
+  tt_assert(fast_mem_is_zero(buf, 10));
+  tt_assert(fast_mem_is_zero(buf, 20));
+  tt_assert(fast_mem_is_zero(buf, 128));
+  tt_assert(!fast_mem_is_zero(buf, 129));
   buf[60] = (char)255;
-  tt_assert(!tor_mem_is_zero(buf, 128));
+  tt_assert(!fast_mem_is_zero(buf, 128));
   buf[0] = (char)1;
-  tt_assert(!tor_mem_is_zero(buf, 10));
+  tt_assert(!fast_mem_is_zero(buf, 10));
 
   /* Test 'escaped' */
   tt_ptr_op(escaped(NULL), OP_EQ, NULL);
@@ -3789,7 +3789,7 @@ test_util_memarea(void *arg)
   tt_int_op(((uintptr_t)p3) % sizeof(void*),OP_EQ, 0);
   tt_assert(!memarea_owns_ptr(area, p3+8192));
   tt_assert(!memarea_owns_ptr(area, p3+30));
-  tt_assert(tor_mem_is_zero(p2, 52));
+  tt_assert(fast_mem_is_zero(p2, 52));
   /* Make sure we don't overalign. */
   p1 = memarea_alloc(area, 1);
   p2 = memarea_alloc(area, 1);
@@ -6116,9 +6116,9 @@ test_util_log_mallinfo(void *arg)
   } else {
     tt_u64_op(mem1, OP_LT, mem2);
   }
-#else
+#else /* !(defined(HAVE_MALLINFO)) */
   tt_skip();
-#endif
+#endif /* defined(HAVE_MALLINFO) */
  done:
   teardown_capture_of_logs();
   tor_free(log1);
@@ -6132,10 +6132,12 @@ test_util_map_anon(void *arg)
   (void)arg;
   char *ptr = NULL;
   size_t sz = 16384;
+  unsigned inherit=0;
 
   /* Basic checks. */
-  ptr = tor_mmap_anonymous(sz, 0);
+  ptr = tor_mmap_anonymous(sz, 0, &inherit);
   tt_ptr_op(ptr, OP_NE, 0);
+  tt_int_op(inherit, OP_EQ, INHERIT_RES_KEEP);
   ptr[sz-1] = 3;
   tt_int_op(ptr[0], OP_EQ, 0);
   tt_int_op(ptr[sz-2], OP_EQ, 0);
@@ -6143,8 +6145,9 @@ test_util_map_anon(void *arg)
 
   /* Try again, with a private (non-swappable) mapping. */
   tor_munmap_anonymous(ptr, sz);
-  ptr = tor_mmap_anonymous(sz, ANONMAP_PRIVATE);
+  ptr = tor_mmap_anonymous(sz, ANONMAP_PRIVATE, &inherit);
   tt_ptr_op(ptr, OP_NE, 0);
+  tt_int_op(inherit, OP_EQ, INHERIT_RES_KEEP);
   ptr[sz-1] = 10;
   tt_int_op(ptr[0], OP_EQ, 0);
   tt_int_op(ptr[sz/2], OP_EQ, 0);
@@ -6152,7 +6155,7 @@ test_util_map_anon(void *arg)
 
   /* Now let's test a drop-on-fork mapping. */
   tor_munmap_anonymous(ptr, sz);
-  ptr = tor_mmap_anonymous(sz, ANONMAP_NOINHERIT);
+  ptr = tor_mmap_anonymous(sz, ANONMAP_NOINHERIT, &inherit);
   tt_ptr_op(ptr, OP_NE, 0);
   ptr[sz-1] = 10;
   tt_int_op(ptr[0], OP_EQ, 0);
@@ -6167,12 +6170,12 @@ static void
 test_util_map_anon_nofork(void *arg)
 {
   (void)arg;
-#if !defined(HAVE_MADVISE) && !defined(HAVE_MINHERIT)
-  /* The operating system doesn't support this. */
+#ifdef _WIN32
+  /* The operating system doesn't support forking. */
   tt_skip();
  done:
   ;
-#else
+#else /* !(defined(_WIN32)) */
   /* We have the right OS support.  We're going to try marking the buffer as
    * either zero-on-fork or as drop-on-fork, whichever is supported.  Then we
    * will fork and send a byte back to the parent process.  This will either
@@ -6181,9 +6184,10 @@ test_util_map_anon_nofork(void *arg)
   char *ptr = NULL;
   size_t sz = 16384;
   int pipefd[2] = {-1, -1};
+  unsigned inherit=0;
 
   tor_munmap_anonymous(ptr, sz);
-  ptr = tor_mmap_anonymous(sz, ANONMAP_NOINHERIT);
+  ptr = tor_mmap_anonymous(sz, ANONMAP_NOINHERIT, &inherit);
   tt_ptr_op(ptr, OP_NE, 0);
   memset(ptr, 0xd0, sz);
 
@@ -6204,15 +6208,36 @@ test_util_map_anon_nofork(void *arg)
   pipefd[1] = -1;
   char buf[1];
   ssize_t r = read(pipefd[0], buf, 1);
-#if defined(INHERIT_ZERO) || defined(MADV_WIPEONFORK)
-  tt_int_op((int)r, OP_EQ, 1); // child should send us a byte.
-  tt_int_op(buf[0], OP_EQ, 0);
-#else
-  tt_int_op(r, OP_LE, 0); // child said nothing; it should have crashed.
-#endif
+
+  if (inherit == INHERIT_RES_ZERO) {
+    // We should be seeing clear-on-fork behavior.
+    tt_int_op((int)r, OP_EQ, 1); // child should send us a byte.
+    tt_int_op(buf[0], OP_EQ, 0); // that byte should be zero.
+  } else if (inherit == INHERIT_RES_DROP) {
+    // We should be seeing noinherit behavior.
+    tt_int_op(r, OP_LE, 0); // child said nothing; it should have crashed.
+  } else {
+    // noinherit isn't implemented.
+    tt_int_op(inherit, OP_EQ, INHERIT_RES_KEEP);
+    tt_int_op((int)r, OP_EQ, 1); // child should send us a byte.
+    tt_int_op(buf[0], OP_EQ, 0xd0); // that byte should what we set it to.
+  }
+
   int ws;
   waitpid(child, &ws, 0);
 
+#ifndef NOINHERIT_CAN_FAIL
+  /* Only if NOINHERIT_CAN_FAIL should it be possible for us to get
+   * INHERIT_KEEP behavior in this case. */
+  tt_int_op(inherit, OP_NE, INHERIT_RES_KEEP);
+#else
+  if (inherit == INHERIT_RES_KEEP) {
+    /* Call this test "skipped", not "passed", since noinherit wasn't
+     * implemented. */
+    tt_skip();
+  }
+#endif /* !defined(NOINHERIT_CAN_FAIL) */
+
  done:
   tor_munmap_anonymous(ptr, sz);
   if (pipefd[0] >= 0) {
@@ -6221,7 +6246,7 @@ test_util_map_anon_nofork(void *arg)
   if (pipefd[1] >= 0) {
     close(pipefd[1]);
   }
-#endif
+#endif /* defined(_WIN32) */
 }
 
 #define UTIL_LEGACY(name)                                               \
@@ -6362,6 +6387,6 @@ struct testcase_t util_tests[] = {
   UTIL_TEST(get_unquoted_path, 0),
   UTIL_TEST(log_mallinfo, 0),
   UTIL_TEST(map_anon, 0),
-  UTIL_TEST(map_anon_nofork, TT_SKIP /* See bug #29535 */),
+  UTIL_TEST(map_anon_nofork, 0),
   END_OF_TESTCASES
 };
diff --git a/src/test/test_util_format.c b/src/test/test_util_format.c
index 3a0b41faa..2859da66b 100644
--- a/src/test/test_util_format.c
+++ b/src/test/test_util_format.c
@@ -346,7 +346,7 @@ test_util_format_base32_decode(void *arg)
     const char *src = "mjwgc2dcnrswqmjs";
 
     ret = base32_decode(dst, strlen(expected), src, strlen(src));
-    tt_int_op(ret, OP_EQ, 0);
+    tt_int_op(ret, OP_EQ, 10);
     tt_str_op(expected, OP_EQ, dst);
   }
 
@@ -357,7 +357,7 @@ test_util_format_base32_decode(void *arg)
     const char *src = "mjwgc2dcnrswq";
 
     ret = base32_decode(dst, strlen(expected), src, strlen(src));
-    tt_int_op(ret, OP_EQ, 0);
+    tt_int_op(ret, OP_EQ, 8);
     tt_mem_op(expected, OP_EQ, dst, strlen(expected));
   }
 
@@ -367,7 +367,7 @@ test_util_format_base32_decode(void *arg)
     ret = base32_decode(dst, real_dstlen, "#abcde", 6);
     tt_int_op(ret, OP_EQ, -1);
     /* Make sure the destination buffer has been zeroed even on error. */
-    tt_int_op(tor_mem_is_zero(dst, real_dstlen), OP_EQ, 1);
+    tt_int_op(fast_mem_is_zero(dst, real_dstlen), OP_EQ, 1);
   }
 
  done:
diff --git a/src/test/test_voting_flags.c b/src/test/test_voting_flags.c
index 5c9eebd00..c8111ea5d 100644
--- a/src/test/test_voting_flags.c
+++ b/src/test/test_voting_flags.c
@@ -60,7 +60,7 @@ check_result(flag_vote_test_cfg_t *c)
   bool result = false;
   routerstatus_t rs;
   memset(&rs, 0, sizeof(rs));
-  set_routerstatus_from_routerinfo(&rs, &c->node, &c->ri, c->now, 0);
+  dirauth_set_routerstatus_from_routerinfo(&rs, &c->node, &c->ri, c->now, 0);
 
   tt_i64_op(rs.published_on, OP_EQ, c->expected.published_on);
   tt_str_op(rs.nickname, OP_EQ, c->expected.nickname);
diff --git a/src/test/test_workqueue_cancel.sh b/src/test/test_workqueue_cancel.sh
index f7c663171..e50b884f2 100755
--- a/src/test/test_workqueue_cancel.sh
+++ b/src/test/test_workqueue_cancel.sh
@@ -1,4 +1,4 @@
 #!/bin/sh
 
-${builddir:-.}/src/test/test_workqueue -C 1
+"${builddir:-.}/src/test/test_workqueue" -C 1
 
diff --git a/src/test/test_workqueue_efd.sh b/src/test/test_workqueue_efd.sh
index 4d8939681..592841fc9 100755
--- a/src/test/test_workqueue_efd.sh
+++ b/src/test/test_workqueue_efd.sh
@@ -1,4 +1,4 @@
 #!/bin/sh
 
-${builddir:-.}/src/test/test_workqueue \
+"${builddir:-.}/src/test/test_workqueue" \
 	   --no-eventfd2 --no-pipe2 --no-pipe --no-socketpair
diff --git a/src/test/test_workqueue_efd2.sh b/src/test/test_workqueue_efd2.sh
index 7cfff45ff..4cf1b76cb 100755
--- a/src/test/test_workqueue_efd2.sh
+++ b/src/test/test_workqueue_efd2.sh
@@ -1,4 +1,4 @@
 #!/bin/sh
 
-${builddir:-.}/src/test/test_workqueue \
+"${builddir:-.}/src/test/test_workqueue" \
 	   --no-eventfd --no-pipe2 --no-pipe --no-socketpair
diff --git a/src/test/test_workqueue_pipe.sh b/src/test/test_workqueue_pipe.sh
index afcef8785..fc3ef34c6 100755
--- a/src/test/test_workqueue_pipe.sh
+++ b/src/test/test_workqueue_pipe.sh
@@ -1,4 +1,4 @@
 #!/bin/sh
 
-${builddir:-.}/src/test/test_workqueue \
+"${builddir:-.}/src/test/test_workqueue" \
 	   --no-eventfd2 --no-eventfd --no-pipe2 --no-socketpair
diff --git a/src/test/test_workqueue_pipe2.sh b/src/test/test_workqueue_pipe2.sh
index a20a1427e..7f19ea880 100755
--- a/src/test/test_workqueue_pipe2.sh
+++ b/src/test/test_workqueue_pipe2.sh
@@ -1,4 +1,4 @@
 #!/bin/sh
 
-${builddir:-.}/src/test/test_workqueue \
+"${builddir:-.}/src/test/test_workqueue" \
 	   --no-eventfd2 --no-eventfd --no-pipe --no-socketpair
diff --git a/src/test/test_workqueue_socketpair.sh b/src/test/test_workqueue_socketpair.sh
index 76af79746..1ee177644 100755
--- a/src/test/test_workqueue_socketpair.sh
+++ b/src/test/test_workqueue_socketpair.sh
@@ -1,4 +1,4 @@
 #!/bin/sh
 
-${builddir:-.}/src/test/test_workqueue \
+"${builddir:-.}/src/test/test_workqueue" \
 	   --no-eventfd2 --no-eventfd --no-pipe2 --no-pipe
diff --git a/src/test/testing_common.c b/src/test/testing_common.c
index 8fc8ef783..ad22898ce 100644
--- a/src/test/testing_common.c
+++ b/src/test/testing_common.c
@@ -12,6 +12,7 @@
 #include "orconfig.h"
 #include "core/or/or.h"
 #include "feature/control/control.h"
+#include "feature/control/control_events.h"
 #include "app/config/config.h"
 #include "lib/crypt_ops/crypto_dh.h"
 #include "lib/crypt_ops/crypto_ed25519.h"
@@ -242,7 +243,7 @@ tinytest_postfork(void)
 }
 
 static void
-log_callback_failure(int severity, uint32_t domain, const char *msg)
+log_callback_failure(int severity, log_domain_mask_t domain, const char *msg)
 {
   (void)msg;
   if (severity == LOG_ERR || (domain & LD_BUG)) {
diff --git a/src/test/testing_rsakeys.c b/src/test/testing_rsakeys.c
index 0f22d4e01..8ba6bf9fe 100644
--- a/src/test/testing_rsakeys.c
+++ b/src/test/testing_rsakeys.c
@@ -448,7 +448,8 @@ static int next_key_idx_2048;
 static crypto_pk_t *
 pk_generate_internal(int bits)
 {
-  tor_assert(bits == 2048 || bits == 1024);
+  tor_assertf(bits == 2048 || bits == 1024,
+             "Wrong key size: %d", bits);
 
 #ifdef USE_PREGENERATED_RSA_KEYS
   int *idxp;
diff --git a/src/test/zero_length_keys.sh b/src/test/zero_length_keys.sh
index 5635bdfd8..1702d1124 100755
--- a/src/test/zero_length_keys.sh
+++ b/src/test/zero_length_keys.sh
@@ -19,7 +19,7 @@
 #   3: a command failed - the test could not be completed
 #
 
-if [ $# -eq 0 ] || [ ! -f ${1} ] || [ ! -x ${1} ]; then
+if [ $# -eq 0 ] || [ ! -f "${1}" ] || [ ! -x "${1}" ]; then
   echo "Usage: ${0} PATH_TO_TOR [-z|-d|-e]"
   exit 1
 elif [ $# -eq 1 ]; then
@@ -31,7 +31,7 @@ else #[$# -gt 1 ]; then
   shift
 fi
 
-DATA_DIR=`mktemp -d -t tor_zero_length_keys.XXXXXX`
+DATA_DIR=$(mktemp -d -t tor_zero_length_keys.XXXXXX)
 if [ -z "$DATA_DIR" ]; then
   echo "Failure: mktemp invocation returned empty string" >&2
   exit 3
@@ -40,7 +40,7 @@ if [ ! -d "$DATA_DIR" ]; then
   echo "Failure: mktemp invocation result doesn't point to directory" >&2
   exit 3
 fi
-trap "rm -rf '$DATA_DIR'" 0
+trap 'rm -rf "$DATA_DIR"' 0
 
 touch "$DATA_DIR"/empty_torrc
 touch "$DATA_DIR"/empty_defaults_torrc
diff --git a/src/tools/tor-gencert.c b/src/tools/tor-gencert.c
index 25113420d..ea96f41db 100644
--- a/src/tools/tor-gencert.c
+++ b/src/tools/tor-gencert.c
@@ -31,7 +31,7 @@ DISABLE_GCC_WARNING(redundant-decls)
 #include <openssl/err.h>
 
 ENABLE_GCC_WARNING(redundant-decls)
-#endif
+#endif /* defined(ENABLE_OPENSSL) */
 
 #include <errno.h>
 
diff --git a/src/tools/tor-resolve.c b/src/tools/tor-resolve.c
index 98b3a4a74..5d97696c1 100644
--- a/src/tools/tor-resolve.c
+++ b/src/tools/tor-resolve.c
@@ -424,6 +424,7 @@ do_resolve(const char *hostname,
     if (parsed < 2) {
       log_err(LD_NET, "Failed to parse SOCKS5 method selection "
                       "message");
+      socks5_server_method_free(m);
       goto err;
     }
 
diff --git a/src/trunnel/ed25519_cert.trunnel b/src/trunnel/ed25519_cert.trunnel
index 8d6483d55..e424ce546 100644
--- a/src/trunnel/ed25519_cert.trunnel
+++ b/src/trunnel/ed25519_cert.trunnel
@@ -28,12 +28,6 @@ const LS_IPV6 = 0x01;
 const LS_LEGACY_ID = 0x02;
 const LS_ED25519_ID = 0x03;
 
-// XXX hs_link_specifier_dup() violates the opaqueness of link_specifier_t by
-//  taking its sizeof(). If we ever want to turn on TRUNNEL_OPAQUE, or
-//  if we ever make link_specifier contain other types, we will
-//  need to refactor that function to do the copy by encoding and decoding the
-//  object.
-
 // amended from tor.trunnel
 struct link_specifier {
   u8 ls_type;
diff --git a/src/trunnel/include.am b/src/trunnel/include.am
index 4f4f1d362..ce15570b1 100644
--- a/src/trunnel/include.am
+++ b/src/trunnel/include.am
@@ -11,6 +11,7 @@ TRUNNELINPUTS = \
 	src/trunnel/link_handshake.trunnel \
 	src/trunnel/pwbox.trunnel \
 	src/trunnel/channelpadding_negotiation.trunnel \
+	src/trunnel/sendme.trunnel \
 	src/trunnel/socks5.trunnel \
 	src/trunnel/circpad_negotiation.trunnel
 
@@ -24,6 +25,7 @@ TRUNNELSOURCES = \
 	src/trunnel/hs/cell_introduce1.c \
 	src/trunnel/hs/cell_rendezvous.c \
 	src/trunnel/channelpadding_negotiation.c \
+	src/trunnel/sendme.c                    \
 	src/trunnel/socks5.c \
 	src/trunnel/netinfo.c \
 	src/trunnel/circpad_negotiation.c
@@ -40,6 +42,7 @@ TRUNNELHEADERS = \
 	src/trunnel/hs/cell_introduce1.h \
 	src/trunnel/hs/cell_rendezvous.h \
 	src/trunnel/channelpadding_negotiation.h \
+	src/trunnel/sendme.h                    \
 	src/trunnel/socks5.h                    \
 	src/trunnel/netinfo.h \
 	src/trunnel/circpad_negotiation.h
diff --git a/src/trunnel/sendme.c b/src/trunnel/sendme.c
new file mode 100644
index 000000000..262b91523
--- /dev/null
+++ b/src/trunnel/sendme.c
@@ -0,0 +1,347 @@
+/* sendme.c -- generated by Trunnel v1.5.2.
+ * https://gitweb.torproject.org/trunnel.git
+ * You probably shouldn't edit this file.
+ */
+#include <stdlib.h>
+#include "trunnel-impl.h"
+
+#include "sendme.h"
+
+#define TRUNNEL_SET_ERROR_CODE(obj) \
+  do {                              \
+    (obj)->trunnel_error_code_ = 1; \
+  } while (0)
+
+#if defined(__COVERITY__) || defined(__clang_analyzer__)
+/* If we're running a static analysis tool, we don't want it to complain
+ * that some of our remaining-bytes checks are dead-code. */
+int sendme_deadcode_dummy__ = 0;
+#define OR_DEADCODE_DUMMY || sendme_deadcode_dummy__
+#else
+#define OR_DEADCODE_DUMMY
+#endif
+
+#define CHECK_REMAINING(nbytes, label)                           \
+  do {                                                           \
+    if (remaining < (nbytes) OR_DEADCODE_DUMMY) {                \
+      goto label;                                                \
+    }                                                            \
+  } while (0)
+
+sendme_cell_t *
+sendme_cell_new(void)
+{
+  sendme_cell_t *val = trunnel_calloc(1, sizeof(sendme_cell_t));
+  if (NULL == val)
+    return NULL;
+  return val;
+}
+
+/** Release all storage held inside 'obj', but do not free 'obj'.
+ */
+static void
+sendme_cell_clear(sendme_cell_t *obj)
+{
+  (void) obj;
+}
+
+void
+sendme_cell_free(sendme_cell_t *obj)
+{
+  if (obj == NULL)
+    return;
+  sendme_cell_clear(obj);
+  trunnel_memwipe(obj, sizeof(sendme_cell_t));
+  trunnel_free_(obj);
+}
+
+uint8_t
+sendme_cell_get_version(const sendme_cell_t *inp)
+{
+  return inp->version;
+}
+int
+sendme_cell_set_version(sendme_cell_t *inp, uint8_t val)
+{
+  if (! ((val == 0 || val == 1))) {
+     TRUNNEL_SET_ERROR_CODE(inp);
+     return -1;
+  }
+  inp->version = val;
+  return 0;
+}
+uint16_t
+sendme_cell_get_data_len(const sendme_cell_t *inp)
+{
+  return inp->data_len;
+}
+int
+sendme_cell_set_data_len(sendme_cell_t *inp, uint16_t val)
+{
+  inp->data_len = val;
+  return 0;
+}
+size_t
+sendme_cell_getlen_data_v1_digest(const sendme_cell_t *inp)
+{
+  (void)inp;  return TRUNNEL_SENDME_V1_DIGEST_LEN;
+}
+
+uint8_t
+sendme_cell_get_data_v1_digest(sendme_cell_t *inp, size_t idx)
+{
+  trunnel_assert(idx < TRUNNEL_SENDME_V1_DIGEST_LEN);
+  return inp->data_v1_digest[idx];
+}
+
+uint8_t
+sendme_cell_getconst_data_v1_digest(const sendme_cell_t *inp, size_t idx)
+{
+  return sendme_cell_get_data_v1_digest((sendme_cell_t*)inp, idx);
+}
+int
+sendme_cell_set_data_v1_digest(sendme_cell_t *inp, size_t idx, uint8_t elt)
+{
+  trunnel_assert(idx < TRUNNEL_SENDME_V1_DIGEST_LEN);
+  inp->data_v1_digest[idx] = elt;
+  return 0;
+}
+
+uint8_t *
+sendme_cell_getarray_data_v1_digest(sendme_cell_t *inp)
+{
+  return inp->data_v1_digest;
+}
+const uint8_t  *
+sendme_cell_getconstarray_data_v1_digest(const sendme_cell_t *inp)
+{
+  return (const uint8_t  *)sendme_cell_getarray_data_v1_digest((sendme_cell_t*)inp);
+}
+const char *
+sendme_cell_check(const sendme_cell_t *obj)
+{
+  if (obj == NULL)
+    return "Object was NULL";
+  if (obj->trunnel_error_code_)
+    return "A set function failed on this object";
+  if (! (obj->version == 0 || obj->version == 1))
+    return "Integer out of bounds";
+  switch (obj->version) {
+
+    case 0:
+      break;
+
+    case 1:
+      break;
+
+    default:
+        return "Bad tag for union";
+      break;
+  }
+  return NULL;
+}
+
+ssize_t
+sendme_cell_encoded_len(const sendme_cell_t *obj)
+{
+  ssize_t result = 0;
+
+  if (NULL != sendme_cell_check(obj))
+     return -1;
+
+
+  /* Length of u8 version IN [0, 1] */
+  result += 1;
+
+  /* Length of u16 data_len */
+  result += 2;
+  switch (obj->version) {
+
+    case 0:
+      break;
+
+    case 1:
+
+      /* Length of u8 data_v1_digest[TRUNNEL_SENDME_V1_DIGEST_LEN] */
+      result += TRUNNEL_SENDME_V1_DIGEST_LEN;
+      break;
+
+    default:
+      trunnel_assert(0);
+      break;
+  }
+  return result;
+}
+int
+sendme_cell_clear_errors(sendme_cell_t *obj)
+{
+  int r = obj->trunnel_error_code_;
+  obj->trunnel_error_code_ = 0;
+  return r;
+}
+ssize_t
+sendme_cell_encode(uint8_t *output, const size_t avail, const sendme_cell_t *obj)
+{
+  ssize_t result = 0;
+  size_t written = 0;
+  uint8_t *ptr = output;
+  const char *msg;
+#ifdef TRUNNEL_CHECK_ENCODED_LEN
+  const ssize_t encoded_len = sendme_cell_encoded_len(obj);
+#endif
+
+  uint8_t *backptr_data_len = NULL;
+
+  if (NULL != (msg = sendme_cell_check(obj)))
+    goto check_failed;
+
+#ifdef TRUNNEL_CHECK_ENCODED_LEN
+  trunnel_assert(encoded_len >= 0);
+#endif
+
+  /* Encode u8 version IN [0, 1] */
+  trunnel_assert(written <= avail);
+  if (avail - written < 1)
+    goto truncated;
+  trunnel_set_uint8(ptr, (obj->version));
+  written += 1; ptr += 1;
+
+  /* Encode u16 data_len */
+  backptr_data_len = ptr;
+  trunnel_assert(written <= avail);
+  if (avail - written < 2)
+    goto truncated;
+  trunnel_set_uint16(ptr, trunnel_htons(obj->data_len));
+  written += 2; ptr += 2;
+  {
+    size_t written_before_union = written;
+
+    /* Encode union data[version] */
+    trunnel_assert(written <= avail);
+    switch (obj->version) {
+
+      case 0:
+        break;
+
+      case 1:
+
+        /* Encode u8 data_v1_digest[TRUNNEL_SENDME_V1_DIGEST_LEN] */
+        trunnel_assert(written <= avail);
+        if (avail - written < TRUNNEL_SENDME_V1_DIGEST_LEN)
+          goto truncated;
+        memcpy(ptr, obj->data_v1_digest, TRUNNEL_SENDME_V1_DIGEST_LEN);
+        written += TRUNNEL_SENDME_V1_DIGEST_LEN; ptr += TRUNNEL_SENDME_V1_DIGEST_LEN;
+        break;
+
+      default:
+        trunnel_assert(0);
+        break;
+    }
+    /* Write the length field back to data_len */
+    trunnel_assert(written >= written_before_union);
+#if UINT16_MAX < SIZE_MAX
+    if (written - written_before_union > UINT16_MAX)
+      goto check_failed;
+#endif
+    trunnel_set_uint16(backptr_data_len, trunnel_htons(written - written_before_union));
+  }
+
+
+  trunnel_assert(ptr == output + written);
+#ifdef TRUNNEL_CHECK_ENCODED_LEN
+  {
+    trunnel_assert(encoded_len >= 0);
+    trunnel_assert((size_t)encoded_len == written);
+  }
+
+#endif
+
+  return written;
+
+ truncated:
+  result = -2;
+  goto fail;
+ check_failed:
+  (void)msg;
+  result = -1;
+  goto fail;
+ fail:
+  trunnel_assert(result < 0);
+  return result;
+}
+
+/** As sendme_cell_parse(), but do not allocate the output object.
+ */
+static ssize_t
+sendme_cell_parse_into(sendme_cell_t *obj, const uint8_t *input, const size_t len_in)
+{
+  const uint8_t *ptr = input;
+  size_t remaining = len_in;
+  ssize_t result = 0;
+  (void)result;
+
+  /* Parse u8 version IN [0, 1] */
+  CHECK_REMAINING(1, truncated);
+  obj->version = (trunnel_get_uint8(ptr));
+  remaining -= 1; ptr += 1;
+  if (! (obj->version == 0 || obj->version == 1))
+    goto fail;
+
+  /* Parse u16 data_len */
+  CHECK_REMAINING(2, truncated);
+  obj->data_len = trunnel_ntohs(trunnel_get_uint16(ptr));
+  remaining -= 2; ptr += 2;
+  {
+    size_t remaining_after;
+    CHECK_REMAINING(obj->data_len, truncated);
+    remaining_after = remaining - obj->data_len;
+    remaining = obj->data_len;
+
+    /* Parse union data[version] */
+    switch (obj->version) {
+
+      case 0:
+        /* Skip to end of union */
+        ptr += remaining; remaining = 0;
+        break;
+
+      case 1:
+
+        /* Parse u8 data_v1_digest[TRUNNEL_SENDME_V1_DIGEST_LEN] */
+        CHECK_REMAINING(TRUNNEL_SENDME_V1_DIGEST_LEN, fail);
+        memcpy(obj->data_v1_digest, ptr, TRUNNEL_SENDME_V1_DIGEST_LEN);
+        remaining -= TRUNNEL_SENDME_V1_DIGEST_LEN; ptr += TRUNNEL_SENDME_V1_DIGEST_LEN;
+        break;
+
+      default:
+        goto fail;
+        break;
+    }
+    if (remaining != 0)
+      goto fail;
+    remaining = remaining_after;
+  }
+  trunnel_assert(ptr + remaining == input + len_in);
+  return len_in - remaining;
+
+ truncated:
+  return -2;
+ fail:
+  result = -1;
+  return result;
+}
+
+ssize_t
+sendme_cell_parse(sendme_cell_t **output, const uint8_t *input, const size_t len_in)
+{
+  ssize_t result;
+  *output = sendme_cell_new();
+  if (NULL == *output)
+    return -1;
+  result = sendme_cell_parse_into(*output, input, len_in);
+  if (result < 0) {
+    sendme_cell_free(*output);
+    *output = NULL;
+  }
+  return result;
+}
diff --git a/src/trunnel/sendme.h b/src/trunnel/sendme.h
new file mode 100644
index 000000000..f3c3dd78c
--- /dev/null
+++ b/src/trunnel/sendme.h
@@ -0,0 +1,101 @@
+/* sendme.h -- generated by Trunnel v1.5.2.
+ * https://gitweb.torproject.org/trunnel.git
+ * You probably shouldn't edit this file.
+ */
+#ifndef TRUNNEL_SENDME_H
+#define TRUNNEL_SENDME_H
+
+#include <stdint.h>
+#include "trunnel.h"
+
+#define TRUNNEL_SENDME_V1_DIGEST_LEN 20
+#if !defined(TRUNNEL_OPAQUE) && !defined(TRUNNEL_OPAQUE_SENDME_CELL)
+struct sendme_cell_st {
+  uint8_t version;
+  uint16_t data_len;
+  uint8_t data_v1_digest[TRUNNEL_SENDME_V1_DIGEST_LEN];
+  uint8_t trunnel_error_code_;
+};
+#endif
+typedef struct sendme_cell_st sendme_cell_t;
+/** Return a newly allocated sendme_cell with all elements set to
+ * zero.
+ */
+sendme_cell_t *sendme_cell_new(void);
+/** Release all storage held by the sendme_cell in 'victim'. (Do
+ * nothing if 'victim' is NULL.)
+ */
+void sendme_cell_free(sendme_cell_t *victim);
+/** Try to parse a sendme_cell from the buffer in 'input', using up to
+ * 'len_in' bytes from the input buffer. On success, return the number
+ * of bytes consumed and set *output to the newly allocated
+ * sendme_cell_t. On failure, return -2 if the input appears
+ * truncated, and -1 if the input is otherwise invalid.
+ */
+ssize_t sendme_cell_parse(sendme_cell_t **output, const uint8_t *input, const size_t len_in);
+/** Return the number of bytes we expect to need to encode the
+ * sendme_cell in 'obj'. On failure, return a negative value. Note
+ * that this value may be an overestimate, and can even be an
+ * underestimate for certain unencodeable objects.
+ */
+ssize_t sendme_cell_encoded_len(const sendme_cell_t *obj);
+/** Try to encode the sendme_cell from 'input' into the buffer at
+ * 'output', using up to 'avail' bytes of the output buffer. On
+ * success, return the number of bytes used. On failure, return -2 if
+ * the buffer was not long enough, and -1 if the input was invalid.
+ */
+ssize_t sendme_cell_encode(uint8_t *output, size_t avail, const sendme_cell_t *input);
+/** Check whether the internal state of the sendme_cell in 'obj' is
+ * consistent. Return NULL if it is, and a short message if it is not.
+ */
+const char *sendme_cell_check(const sendme_cell_t *obj);
+/** Clear any errors that were set on the object 'obj' by its setter
+ * functions. Return true iff errors were cleared.
+ */
+int sendme_cell_clear_errors(sendme_cell_t *obj);
+/** Return the value of the version field of the sendme_cell_t in
+ * 'inp'
+ */
+uint8_t sendme_cell_get_version(const sendme_cell_t *inp);
+/** Set the value of the version field of the sendme_cell_t in 'inp'
+ * to 'val'. Return 0 on success; return -1 and set the error code on
+ * 'inp' on failure.
+ */
+int sendme_cell_set_version(sendme_cell_t *inp, uint8_t val);
+/** Return the value of the data_len field of the sendme_cell_t in
+ * 'inp'
+ */
+uint16_t sendme_cell_get_data_len(const sendme_cell_t *inp);
+/** Set the value of the data_len field of the sendme_cell_t in 'inp'
+ * to 'val'. Return 0 on success; return -1 and set the error code on
+ * 'inp' on failure.
+ */
+int sendme_cell_set_data_len(sendme_cell_t *inp, uint16_t val);
+/** Return the (constant) length of the array holding the
+ * data_v1_digest field of the sendme_cell_t in 'inp'.
+ */
+size_t sendme_cell_getlen_data_v1_digest(const sendme_cell_t *inp);
+/** Return the element at position 'idx' of the fixed array field
+ * data_v1_digest of the sendme_cell_t in 'inp'.
+ */
+uint8_t sendme_cell_get_data_v1_digest(sendme_cell_t *inp, size_t idx);
+/** As sendme_cell_get_data_v1_digest, but take and return a const
+ * pointer
+ */
+uint8_t sendme_cell_getconst_data_v1_digest(const sendme_cell_t *inp, size_t idx);
+/** Change the element at position 'idx' of the fixed array field
+ * data_v1_digest of the sendme_cell_t in 'inp', so that it will hold
+ * the value 'elt'.
+ */
+int sendme_cell_set_data_v1_digest(sendme_cell_t *inp, size_t idx, uint8_t elt);
+/** Return a pointer to the TRUNNEL_SENDME_V1_DIGEST_LEN-element array
+ * field data_v1_digest of 'inp'.
+ */
+uint8_t * sendme_cell_getarray_data_v1_digest(sendme_cell_t *inp);
+/** As sendme_cell_get_data_v1_digest, but take and return a const
+ * pointer
+ */
+const uint8_t  * sendme_cell_getconstarray_data_v1_digest(const sendme_cell_t *inp);
+
+
+#endif
diff --git a/src/trunnel/sendme.trunnel b/src/trunnel/sendme.trunnel
new file mode 100644
index 000000000..300963e67
--- /dev/null
+++ b/src/trunnel/sendme.trunnel
@@ -0,0 +1,19 @@
+/* This file contains the SENDME cell definition. */
+
+/* v1 digest length in bytes. */
+const TRUNNEL_SENDME_V1_DIGEST_LEN = 20;
+
+/* SENDME cell declaration. */
+struct sendme_cell {
+  /* Version field. */
+  u8 version IN [0x00, 0x01];
+
+  /* Length of data contained in this cell. */
+  u16 data_len;
+
+  /* The data content depends on the version. */
+  union data[version] with length data_len {
+    0x00: ignore;
+    0x01: u8 v1_digest[TRUNNEL_SENDME_V1_DIGEST_LEN];
+  };
+}
diff --git a/src/win32/orconfig.h b/src/win32/orconfig.h
index adac42268..bb1f42ef1 100644
--- a/src/win32/orconfig.h
+++ b/src/win32/orconfig.h
@@ -218,7 +218,7 @@
 #define USING_TWOS_COMPLEMENT
 
 /* Version number of package */
-#define VERSION "0.4.0.5-dev"
+#define VERSION "0.4.1.5-dev"

    

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