[tor-commits] [tor/master] Make clients wait to refresh bridges when they have a recent descriptor
nickm at torproject.org
nickm at torproject.org
Tue Sep 12 14:41:11 UTC 2017
commit 93a8ed3b83b5f20768562ca2aff4eba7aca667d8
Author: teor <teor2345 at gmail.com>
Date: Mon Sep 11 13:56:35 2017 +1000
Make clients wait to refresh bridges when they have a recent descriptor
But when clients are just starting, make them try each bridge a few times
before giving up on it.
These changes make the bridge download schedules more explicit: before
17750, they relied on undocumented behaviour and specific schedule
entries. (And between 17750 and this fix, they were broken.)
Fixes 23347, not in any released version of tor.
---
changes/bug23347 | 15 +++++++++------
doc/tor.1.txt | 16 ++++++++++++----
src/or/bridges.c | 17 +++++------------
src/or/bridges.h | 2 +-
src/or/config.c | 19 +++++++++++++------
src/or/directory.c | 9 ++++++++-
src/or/or.h | 4 ++++
src/test/test_dir.c | 48 +++++++++++++++++++++++++++++++++++++++---------
src/test/test_options.c | 1 +
9 files changed, 92 insertions(+), 39 deletions(-)
diff --git a/changes/bug23347 b/changes/bug23347
index b0883784d..e73aa48f0 100644
--- a/changes/bug23347
+++ b/changes/bug23347
@@ -1,6 +1,9 @@
- o Minor bug fixes (bridge client bootstrap):
- - Make bridge clients download bridge descriptors immediately.
- The bridge schedules were never correct, but we didn't realise until
- the fix for 17750 made bridge clients hang for 15 minutes before
- bootstrapping.
- Fixes bug 23347. Not in any released version of Tor.
+ o Minor fixes (bridge client bootstrap):
+ - Make bridge clients with no running bridges try to download
+ bridge descriptors immediately. But when bridge clients have
+ running bridges, make them wait at least 3 hours before
+ refreshing recently received bridge descriptors.
+ Download schedules used to start with an implicit 0, but the
+ fix for 17750 changed this undocumented behaviour, and made
+ bridge clients hang for 15 minutes before bootstrapping.
+ Fixes bug 23347, not in any released version of Tor.
diff --git a/doc/tor.1.txt b/doc/tor.1.txt
index e3939d115..d8dbcaa13 100644
--- a/doc/tor.1.txt
+++ b/doc/tor.1.txt
@@ -2475,7 +2475,8 @@ The following options are used for running a testing Tor network.
TestingClientDownloadSchedule 0, 0, 5, 10, 15, 20, 30, 60
TestingServerConsensusDownloadSchedule 0, 0, 5, 10, 15, 20, 30, 60
TestingClientConsensusDownloadSchedule 0, 0, 5, 10, 15, 20, 30, 60
- TestingBridgeDownloadSchedule 0, 5, 10, 30, 60
+ TestingBridgeDownloadSchedule 10, 30, 60
+ TestingBridgeBootstrapDownloadSchedule 0, 0, 5, 10, 15, 20, 30, 60
TestingClientMaxIntervalWithoutRequest 5 seconds
TestingDirConnectionMaxStall 30 seconds
TestingConsensusMaxDownloadTries 80
@@ -2540,9 +2541,16 @@ The following options are used for running a testing Tor network.
1800, 3600, 3600, 3600, 10800, 21600, 43200)
[[TestingBridgeDownloadSchedule]] **TestingBridgeDownloadSchedule** __N__,__N__,__...__::
- Schedule for when clients should download bridge descriptors. Changing this
- requires that **TestingTorNetwork** is set. (Default: 0, 8, 3600, 10800,
- 25200, 54000, 111600, 262800)
+ Schedule for when clients should download each bridge descriptor when they
+ know that one or more of their configured bridges are running. Changing
+ this requires that **TestingTorNetwork** is set. (Default: 10800, 25200,
+ 54000, 111600, 262800)
+
+[[TestingBridgeBootstrapDownloadSchedule]] **TestingBridgeBootstrapDownloadSchedule** __N__,__N__,__...__::
+ Schedule for when clients should download each bridge descriptor when they
+ have just started, or when they can not contact any of their bridges.
+ Changing this requires that **TestingTorNetwork** is set. (Default: 0, 30,
+ 90, 600, 3600, 10800, 25200, 54000, 111600, 262800)
[[TestingClientMaxIntervalWithoutRequest]] **TestingClientMaxIntervalWithoutRequest** __N__ **seconds**|**minutes**::
When directory clients have only a few descriptors to request, they batch
diff --git a/src/or/bridges.c b/src/or/bridges.c
index fc39ccaa9..257bb8920 100644
--- a/src/or/bridges.c
+++ b/src/or/bridges.c
@@ -794,17 +794,10 @@ learned_bridge_descriptor(routerinfo_t *ri, int from_cache)
node_t *node;
/* it's here; schedule its re-fetch for a long time from now. */
if (!from_cache) {
+ /* This schedules the re-fetch at a constant interval, which produces
+ * a pattern of bridge traffic. But it's better than trying all
+ * configured briges several times in the first few minutes. */
download_status_reset(&bridge->fetch_status);
- /* We have two quick attempts in the bridge schedule, and then slow
- * ones */
- download_status_increment_attempt(
- &bridge->fetch_status,
- safe_str_client(fmt_and_decorate_addr(&bridge->addr)),
- now);
- download_status_increment_attempt(
- &bridge->fetch_status,
- safe_str_client(fmt_and_decorate_addr(&bridge->addr)),
- now);
}
node = node_get_mutable_by_id(ri->cache_info.identity_digest);
@@ -837,8 +830,8 @@ learned_bridge_descriptor(routerinfo_t *ri, int from_cache)
* We use this function to decide if we're ready to start building
* circuits through our bridges, or if we need to wait until the
* directory "server/authority" requests finish. */
-int
-any_bridge_descriptors_known(void)
+MOCK_IMPL(int,
+any_bridge_descriptors_known, (void))
{
tor_assert(get_options()->UseBridges);
diff --git a/src/or/bridges.h b/src/or/bridges.h
index 3bfc782f9..19341818f 100644
--- a/src/or/bridges.h
+++ b/src/or/bridges.h
@@ -45,7 +45,7 @@ void bridge_add_from_config(struct bridge_line_t *bridge_line);
void retry_bridge_descriptor_fetch_directly(const char *digest);
void fetch_bridge_descriptors(const or_options_t *options, time_t now);
void learned_bridge_descriptor(routerinfo_t *ri, int from_cache);
-int any_bridge_descriptors_known(void);
+MOCK_DECL(int, any_bridge_descriptors_known, (void));
const smartlist_t *get_socks_args_by_bridge_addrport(const tor_addr_t *addr,
uint16_t port);
diff --git a/src/or/config.c b/src/or/config.c
index 54df6c3e5..90ab0e57f 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -586,10 +586,16 @@ static config_var_t option_vars_[] = {
* blackholed. Clients will try 3 directories simultaneously.
* (Relays never use simultaneous connections.) */
V(ClientBootstrapConsensusMaxInProgressTries, UINT, "3"),
- /* The bridge code relies on the third item in this schedule being slow
- * (~ 1 consensus interval) */
+ /* When a client has any running bridges, check each bridge occasionally,
+ * whether or not that bridge is actually up. */
V(TestingBridgeDownloadSchedule, CSV_INTERVAL,
- "0, 8, 3600, 10800, 25200, 54000, 111600, 262800"),
+ "10800, 25200, 54000, 111600, 262800"),
+ /* When a client is just starting, or has no running bridges, check each
+ * bridge a few times quickly, and then try again later. These schedules
+ * are much longer than the other schedules, because we try each and every
+ * configured bridge with this schedule. */
+ V(TestingBridgeBootstrapDownloadSchedule, CSV_INTERVAL,
+ "0, 30, 90, 600, 3600, 10800, 25200, 54000, 111600, 262800"),
V(TestingClientMaxIntervalWithoutRequest, INTERVAL, "10 minutes"),
V(TestingDirConnectionMaxStall, INTERVAL, "5 minutes"),
V(TestingConsensusMaxDownloadTries, UINT, "8"),
@@ -651,9 +657,9 @@ static const config_var_t testing_tor_network_defaults[] = {
"15, 20, 30, 60"),
V(TestingClientConsensusDownloadSchedule, CSV_INTERVAL, "0, 0, 5, 10, "
"15, 20, 30, 60"),
- /* The bridge code relies on the third item in this schedule being slow
- * (~ 1 consensus interval) */
- V(TestingBridgeDownloadSchedule, CSV_INTERVAL, "0, 5, 10, 30, 60"),
+ V(TestingBridgeDownloadSchedule, CSV_INTERVAL, "10, 30, 60"),
+ V(TestingBridgeBootstrapDownloadSchedule, CSV_INTERVAL, "0, 0, 5, 10, "
+ "15, 20, 30, 60"),
V(TestingClientMaxIntervalWithoutRequest, INTERVAL, "5 seconds"),
V(TestingDirConnectionMaxStall, INTERVAL, "30 seconds"),
V(TestingConsensusMaxDownloadTries, UINT, "80"),
@@ -4066,6 +4072,7 @@ options_validate(or_options_t *old_options, or_options_t *options,
CHECK_DEFAULT(TestingServerConsensusDownloadSchedule);
CHECK_DEFAULT(TestingClientConsensusDownloadSchedule);
CHECK_DEFAULT(TestingBridgeDownloadSchedule);
+ CHECK_DEFAULT(TestingBridgeBootstrapDownloadSchedule);
CHECK_DEFAULT(TestingClientMaxIntervalWithoutRequest);
CHECK_DEFAULT(TestingDirConnectionMaxStall);
CHECK_DEFAULT(TestingConsensusMaxDownloadTries);
diff --git a/src/or/directory.c b/src/or/directory.c
index 6b5e16bfd..9ee6fae4d 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -5342,7 +5342,14 @@ find_dl_schedule(const download_status_t *dls, const or_options_t *options)
}
}
case DL_SCHED_BRIDGE:
- return options->TestingBridgeDownloadSchedule;
+ /* A bridge client downloading bridge descriptors */
+ if (any_bridge_descriptors_known()) {
+ /* A bridge client with one or more running bridges */
+ return options->TestingBridgeDownloadSchedule;
+ } else {
+ /* A bridge client with no running bridges */
+ return options->TestingBridgeBootstrapDownloadSchedule;
+ }
default:
tor_assert(0);
}
diff --git a/src/or/or.h b/src/or/or.h
index 5d55094a0..78b658a79 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -4314,6 +4314,10 @@ typedef struct {
* altered on testing networks. */
smartlist_t *TestingBridgeDownloadSchedule;
+ /** Schedule for when clients should download bridge descriptors when they
+ * have no running bridges. Only altered on testing networks. */
+ smartlist_t *TestingBridgeBootstrapDownloadSchedule;
+
/** When directory clients have only a few descriptors to request, they
* batch them until they have more, or until this amount of time has
* passed. Only altered on testing networks. */
diff --git a/src/test/test_dir.c b/src/test/test_dir.c
index b6b0936f8..dd910cd0c 100644
--- a/src/test/test_dir.c
+++ b/src/test/test_dir.c
@@ -18,6 +18,7 @@
#define RELAY_PRIVATE
#include "or.h"
+#include "bridges.h"
#include "confparse.h"
#include "config.h"
#include "control.h"
@@ -4245,7 +4246,7 @@ test_dir_download_status_increment(void *arg)
/* Put it in the options */
mock_options = &test_options;
reset_options(mock_options, &mock_get_options_calls);
- mock_options->TestingBridgeDownloadSchedule = schedule;
+ mock_options->TestingBridgeBootstrapDownloadSchedule = schedule;
mock_options->TestingClientDownloadSchedule = schedule;
MOCK(get_options, mock_get_options);
@@ -4425,6 +4426,7 @@ test_dir_download_status_increment(void *arg)
/* Check that failure increments do happen on attempt-based schedules,
* but that the retry is set at the end of time */
+ mock_options->UseBridges = 1;
mock_get_options_calls = 0;
next_at = download_status_increment_failure(&dls_attempt, 404, "test", 0,
current_time);
@@ -4539,6 +4541,7 @@ test_dir_download_status_increment(void *arg)
tt_int_op(download_status_get_n_failures(&dls_attempt), OP_EQ, 0);
tt_int_op(download_status_get_n_attempts(&dls_attempt), OP_EQ, 0);
tt_int_op(mock_get_options_calls, OP_GE, 1);
+ mock_options->UseBridges = 0;
/* Check that attempt increments don't happen on failure-based schedules,
* and that the attempt is set at the end of time */
@@ -5859,9 +5862,17 @@ mock_networkstatus_consensus_can_use_extra_fallbacks(
return mock_networkstatus_consensus_can_use_extra_fallbacks_value;
}
-/* data is a 2 character nul-terminated string.
+static int mock_any_bridge_descriptors_known_value = 0;
+static int
+mock_any_bridge_descriptors_known(void)
+{
+ return mock_any_bridge_descriptors_known_value;
+}
+
+/* data is a 3 character nul-terminated string.
* If data[0] is 'b', set bootstrapping, anything else means not bootstrapping
* If data[1] is 'f', set extra fallbacks, anything else means no extra
+ * If data[2] is 'f', set running bridges, anything else means no extra
* fallbacks.
*/
static void
@@ -5869,7 +5880,7 @@ test_dir_find_dl_schedule(void* data)
{
const char *str = (const char *)data;
- tt_assert(strlen(data) == 2);
+ tt_assert(strlen(data) == 3);
if (str[0] == 'b') {
mock_networkstatus_consensus_is_bootstrapping_value = 1;
@@ -5883,15 +5894,23 @@ test_dir_find_dl_schedule(void* data)
mock_networkstatus_consensus_can_use_extra_fallbacks_value = 0;
}
+ if (str[2] == 'r') {
+ mock_any_bridge_descriptors_known_value = 1;
+ } else {
+ mock_any_bridge_descriptors_known_value = 0;
+ }
+
MOCK(networkstatus_consensus_is_bootstrapping,
mock_networkstatus_consensus_is_bootstrapping);
MOCK(networkstatus_consensus_can_use_extra_fallbacks,
mock_networkstatus_consensus_can_use_extra_fallbacks);
+ MOCK(any_bridge_descriptors_known,
+ mock_any_bridge_descriptors_known);
download_status_t dls;
smartlist_t server, client, server_cons, client_cons;
smartlist_t client_boot_auth_only_cons, client_boot_auth_cons;
- smartlist_t client_boot_fallback_cons, bridge;
+ smartlist_t client_boot_fallback_cons, bridge, bridge_bootstrap;
mock_options = tor_malloc(sizeof(or_options_t));
reset_options(mock_options, &mock_get_options_calls);
@@ -5908,6 +5927,7 @@ test_dir_find_dl_schedule(void* data)
mock_options->ClientBootstrapConsensusFallbackDownloadSchedule =
&client_boot_fallback_cons;
mock_options->TestingBridgeDownloadSchedule = &bridge;
+ mock_options->TestingBridgeBootstrapDownloadSchedule = &bridge_bootstrap;
dls.schedule = DL_SCHED_GENERIC;
/* client */
@@ -5996,11 +6016,17 @@ test_dir_find_dl_schedule(void* data)
dls.schedule = DL_SCHED_BRIDGE;
/* client */
mock_options->ClientOnly = 1;
- tt_ptr_op(find_dl_schedule(&dls, mock_options), OP_EQ, &bridge);
+ mock_options->UseBridges = 1;
+ if (any_bridge_descriptors_known()) {
+ tt_ptr_op(find_dl_schedule(&dls, mock_options), OP_EQ, &bridge);
+ } else {
+ tt_ptr_op(find_dl_schedule(&dls, mock_options), OP_EQ, &bridge_bootstrap);
+ }
done:
UNMOCK(networkstatus_consensus_is_bootstrapping);
UNMOCK(networkstatus_consensus_can_use_extra_fallbacks);
+ UNMOCK(any_bridge_descriptors_known);
UNMOCK(get_options);
tor_free(mock_options);
mock_options = NULL;
@@ -6165,10 +6191,14 @@ struct testcase_t dir_tests[] = {
DIR(dump_unparseable_descriptors, 0),
DIR(populate_dump_desc_fifo, 0),
DIR(populate_dump_desc_fifo_2, 0),
- DIR_ARG(find_dl_schedule, TT_FORK, "bf"),
- DIR_ARG(find_dl_schedule, TT_FORK, "ba"),
- DIR_ARG(find_dl_schedule, TT_FORK, "cf"),
- DIR_ARG(find_dl_schedule, TT_FORK, "ca"),
+ DIR_ARG(find_dl_schedule, TT_FORK, "bfd"),
+ DIR_ARG(find_dl_schedule, TT_FORK, "bad"),
+ DIR_ARG(find_dl_schedule, TT_FORK, "cfd"),
+ DIR_ARG(find_dl_schedule, TT_FORK, "cad"),
+ DIR_ARG(find_dl_schedule, TT_FORK, "bfr"),
+ DIR_ARG(find_dl_schedule, TT_FORK, "bar"),
+ DIR_ARG(find_dl_schedule, TT_FORK, "cfr"),
+ DIR_ARG(find_dl_schedule, TT_FORK, "car"),
DIR(assumed_flags, 0),
DIR(networkstatus_compute_bw_weights_v10, 0),
END_OF_TESTCASES
diff --git a/src/test/test_options.c b/src/test/test_options.c
index 5f35c47f7..a9f18c8a8 100644
--- a/src/test/test_options.c
+++ b/src/test/test_options.c
@@ -2230,6 +2230,7 @@ test_options_validate__testing(void *ignored)
ENSURE_DEFAULT(TestingServerConsensusDownloadSchedule, 3000);
ENSURE_DEFAULT(TestingClientConsensusDownloadSchedule, 3000);
ENSURE_DEFAULT(TestingBridgeDownloadSchedule, 3000);
+ ENSURE_DEFAULT(TestingBridgeBootstrapDownloadSchedule, 3000);
ENSURE_DEFAULT(TestingClientMaxIntervalWithoutRequest, 3000);
ENSURE_DEFAULT(TestingDirConnectionMaxStall, 3000);
ENSURE_DEFAULT(TestingConsensusMaxDownloadTries, 3000);
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