[tor-commits] [tor/main] Add a MinTimeToReportBandwidth option; make it 0 for testing networks.
nickm at torproject.org
nickm at torproject.org
Mon Jun 14 17:10:31 UTC 2021
commit 2ae24d003d1d12e8e202748c4398d7438e4a65d9
Author: Nick Mathewson <nickm at torproject.org>
Date: Wed Mar 17 08:45:37 2021 -0400
Add a MinTimeToReportBandwidth option; make it 0 for testing networks.
This option changes the time for which a bandwidth measurement period
must have been in progress before we include it when reporting our
observed bandwidth in our descriptors. Without this option, we only
consider a time period towards our maximum if it has been running
for a full day. Obviously, that's unacceptable for testing
networks, where we'd like to get results as soon as possible.
For non-testing networks, I've put a (somewhat arbitrary) 2-hour
minimum on the option, since there are traffic analysis concerns
with immediate reporting here.
Closes #40337.
---
changes/ticket40337 | 12 ++++++++++++
doc/man/tor.1.txt | 7 +++++++
src/app/config/config.c | 8 ++++++++
src/app/config/config.h | 7 +++++++
src/app/config/or_options_st.h | 4 ++++
src/app/config/testnet.inc | 1 +
src/feature/stats/bwhist.c | 19 ++++++++++++++-----
src/feature/stats/bwhist.h | 2 +-
src/test/test_relay.c | 4 ++--
9 files changed, 56 insertions(+), 8 deletions(-)
diff --git a/changes/ticket40337 b/changes/ticket40337
new file mode 100644
index 0000000000..f8f136a740
--- /dev/null
+++ b/changes/ticket40337
@@ -0,0 +1,12 @@
+ o Minor features (bandwidth reporting):
+ - Relays can now use the MinTimeToReportBandwidth option to change
+ the smallest amount of time over which they're willing to report
+ their observed maximum bandwidth. Previously, this was fixed
+ at 1 day. For safety, values under 2 hours are only supported on
+ testing networks. Part of a fix for ticket 40337.
+
+ o Minor features (testing):
+ - Relays on testing networks now report their observed bandwidths
+ immediately from startup. Previously, they waited
+ until they had been running for a full day. Closes ticket
+ 40337.
diff --git a/doc/man/tor.1.txt b/doc/man/tor.1.txt
index b57c6ec70a..af4ee494ef 100644
--- a/doc/man/tor.1.txt
+++ b/doc/man/tor.1.txt
@@ -2448,6 +2448,13 @@ is non-zero):
If we have more onionskins queued for processing than we can process in
this amount of time, reject new ones. (Default: 1750 msec)
+[[MinTimeToReportBandwidth]] **MinTimeToReportBandwidth** __N__ **seconds**|**minutes**|**hours**::
+ Do not report our measurements for our maximum observed bandwidth for any
+ time period that has lasted for less than this amount of time.
+ Setting this option too low can enable traffic analysis, and is
+ not permitted except on testing networks. Values over 1 day have
+ no effect. (Default: 1 day)
+
[[MyFamily]] **MyFamily** __fingerprint__,__fingerprint__,...::
Declare that this Tor relay is controlled or administered by a group or
organization identical or similar to that of the other relays, defined by
diff --git a/src/app/config/config.c b/src/app/config/config.c
index fa74907b3d..9011f36735 100644
--- a/src/app/config/config.c
+++ b/src/app/config/config.c
@@ -563,6 +563,7 @@ static const config_var_t option_vars_[] = {
V(MaxUnparseableDescSizeToLog, MEMUNIT, "10 MB"),
VPORT(MetricsPort),
V(MetricsPortPolicy, LINELIST, NULL),
+ V(MinTimeToReportBandwidth, INTERVAL, "1 day"),
VAR("MyFamily", LINELIST, MyFamily_lines, NULL),
V(NewCircuitPeriod, INTERVAL, "30 seconds"),
OBSOLETE("NamingAuthoritativeDirectory"),
@@ -3711,6 +3712,13 @@ options_validate_cb(const void *old_options_, void *options_, char **msg)
options->HeartbeatPeriod = MIN_HEARTBEAT_PERIOD;
}
+ if (options->MinTimeToReportBandwidth < MIN_MIN_TIME_TO_REPORT_BW &&
+ !options->TestingTorNetwork) {
+ log_warn(LD_CONFIG, "MinTimeToReportBandwidth is too short; "
+ "raising to %d seconds.", MIN_MIN_TIME_TO_REPORT_BW);
+ options->MinTimeToReportBandwidth = MIN_MIN_TIME_TO_REPORT_BW;
+ }
+
if (options->KeepalivePeriod < 1)
REJECT("KeepalivePeriod option must be positive.");
diff --git a/src/app/config/config.h b/src/app/config/config.h
index e95ef4a728..74e6942eb5 100644
--- a/src/app/config/config.h
+++ b/src/app/config/config.h
@@ -24,6 +24,13 @@
* expose more information than we're comfortable with. */
#define MIN_HEARTBEAT_PERIOD (30*60)
+/**
+ * Lowest allowable value for MinTimeToReportBandwidth on a non-testing
+ * network; if this is too low we might report detail that is too
+ * fine-grained.
+ **/
+#define MIN_MIN_TIME_TO_REPORT_BW (2*60*60)
+
/** Maximum default value for MaxMemInQueues, in bytes. */
#if SIZEOF_VOID_P >= 8
#define MAX_DEFAULT_MEMORY_QUEUE_SIZE (UINT64_C(8) << 30)
diff --git a/src/app/config/or_options_st.h b/src/app/config/or_options_st.h
index 4364f145ed..efecc85d66 100644
--- a/src/app/config/or_options_st.h
+++ b/src/app/config/or_options_st.h
@@ -1082,6 +1082,10 @@ struct or_options_t {
/** List of policy allowed to query the Metrics port. */
struct config_line_t *MetricsPortPolicy;
+ /** How far must we be into the current bandwidth-measurement period to
+ * report bandwidth observations from this period? */
+ int MinTimeToReportBandwidth;
+
/**
* Configuration objects for individual modules.
*
diff --git a/src/app/config/testnet.inc b/src/app/config/testnet.inc
index 00b307782b..527e0d00b1 100644
--- a/src/app/config/testnet.inc
+++ b/src/app/config/testnet.inc
@@ -19,6 +19,7 @@
{ "TestingV3AuthInitialDistDelay", "20 seconds" },
{ "TestingAuthDirTimeToLearnReachability", "0 minutes" },
{ "MinUptimeHidServDirectoryV2", "0 minutes" },
+{ "MinTimeToReportBandwidth", "0 seconds" },
{ "TestingServerDownloadInitialDelay", "0" },
{ "TestingClientDownloadInitialDelay", "0" },
{ "TestingServerConsensusDownloadInitialDelay", "0" },
diff --git a/src/feature/stats/bwhist.c b/src/feature/stats/bwhist.c
index 7cbc5f60a6..55a8f7c747 100644
--- a/src/feature/stats/bwhist.c
+++ b/src/feature/stats/bwhist.c
@@ -206,16 +206,24 @@ bwhist_note_dir_bytes_read(uint64_t num_bytes, time_t when)
add_obs(dir_read_array, when, num_bytes);
}
-/** Helper: Return the largest value in b->maxima. (This is equal to the
+/**
+ * Helper: Return the largest value in b->maxima. (This is equal to the
* most bandwidth used in any NUM_SECS_ROLLING_MEASURE period for the last
* NUM_SECS_BW_SUM_IS_VALID seconds.)
+ *
+ * Also include the current period if we have been observing it for
+ * at least min_observation_time seconds.
*/
STATIC uint64_t
-find_largest_max(bw_array_t *b)
+find_largest_max(bw_array_t *b, int min_observation_time)
{
int i;
uint64_t max;
- max=0;
+ time_t period_start = b->next_period - NUM_SECS_BW_SUM_INTERVAL;
+ if (b->cur_obs_time > period_start + min_observation_time)
+ max = b->max_total;
+ else
+ max = 0;
for (i=0; i<NUM_TOTALS; ++i) {
if (b->maxima[i]>max)
max = b->maxima[i];
@@ -233,8 +241,9 @@ MOCK_IMPL(int,
bwhist_bandwidth_assess,(void))
{
uint64_t w,r;
- r = find_largest_max(read_array);
- w = find_largest_max(write_array);
+ int min_obs_time = get_options()->MinTimeToReportBandwidth;
+ r = find_largest_max(read_array, min_obs_time);
+ w = find_largest_max(write_array, min_obs_time);
if (r>w)
return (int)(((double)w)/NUM_SECS_ROLLING_MEASURE);
else
diff --git a/src/feature/stats/bwhist.h b/src/feature/stats/bwhist.h
index f88b951447..01055df720 100644
--- a/src/feature/stats/bwhist.h
+++ b/src/feature/stats/bwhist.h
@@ -28,7 +28,7 @@ int bwhist_load_state(struct or_state_t *state, char **err);
#ifdef BWHIST_PRIVATE
typedef struct bw_array_t bw_array_t;
-STATIC uint64_t find_largest_max(bw_array_t *b);
+STATIC uint64_t find_largest_max(bw_array_t *b, int min_observation_time);
STATIC void commit_max(bw_array_t *b);
STATIC void advance_obs(bw_array_t *b);
STATIC bw_array_t *bw_array_new(void);
diff --git a/src/test/test_relay.c b/src/test/test_relay.c
index b287f0d38b..8ed29b6282 100644
--- a/src/test/test_relay.c
+++ b/src/test/test_relay.c
@@ -98,7 +98,7 @@ test_relay_close_circuit(void *arg)
tt_int_op(new_count, OP_EQ, old_count + 1);
/* Ensure our write totals are 0 */
- tt_u64_op(find_largest_max(write_array), OP_EQ, 0);
+ tt_u64_op(find_largest_max(write_array, 86400), OP_EQ, 0);
/* Mark the circuit for close */
circuit_mark_for_close(TO_CIRCUIT(orcirc), 0);
@@ -107,7 +107,7 @@ test_relay_close_circuit(void *arg)
advance_obs(write_array);
commit_max(write_array);
/* Check for two cells plus overhead */
- tt_u64_op(find_largest_max(write_array), OP_EQ,
+ tt_u64_op(find_largest_max(write_array, 86400), OP_EQ,
2*(get_cell_network_size(nchan->wide_circ_ids)
+TLS_PER_CELL_OVERHEAD));
More information about the tor-commits
mailing list