commit 977e396e866052a20de73f4e8121e514d4eff774 Author: Roger Dingledine arma@torproject.org Date: Fri Mar 11 22:12:15 2011 -0500

improve accuracy for when a relay went unreachable --- changes/bug2716 | 5 +++++ src/or/dirserv.c | 13 +++++++++---- src/or/dirserv.h | 8 ++++++++ src/or/main.c | 5 +++-- 4 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/changes/bug2716 b/changes/bug2716 new file mode 100644 index 0000000..4663ed3 --- /dev/null +++ b/changes/bug2716 @@ -0,0 +1,5 @@ + o Minor features: + - When a relay has failed several reachability tests, be more accurate + at recording when it became unreachable, so we can in turn provide + more accuracy at assigning Stable, Guard, HSDir, etc flags. Bugfix + on 0.2.0.6-alpha. Resolves bug 2716. diff --git a/src/or/dirserv.c b/src/or/dirserv.c index aeeab45..7386927 100644 --- a/src/or/dirserv.c +++ b/src/or/dirserv.c @@ -970,7 +970,11 @@ dirserv_set_router_is_running(routerinfo_t *router, time_t now)

if (!answer && running_long_enough_to_decide_unreachable()) { /* not considered reachable. tell rephist. */ - rep_hist_note_router_unreachable(router->cache_info.identity_digest, now); + time_t when = now; + if (router->last_reachable && + router->last_reachable + REACHABILITY_TEST_PERIOD < now) + when = router->last_reachable + REACHABILITY_TEST_PERIOD; + rep_hist_note_router_unreachable(router->cache_info.identity_digest, when); }

router->is_running = answer; @@ -3187,7 +3191,8 @@ dirserv_single_reachability_test(time_t now, routerinfo_t *router) * try a few connections per call. * * The load balancing is such that if we get called once every ten - * seconds, we will cycle through all the tests in 1280 seconds (a + * seconds, we will cycle through all the tests in + * 10*REACHABILITY_MASK_PER_TEST seconds (a * bit over 20 minutes). */ void @@ -3214,11 +3219,11 @@ dirserv_test_reachability(time_t now) continue; /* bridge authorities only test reachability on bridges */ // if (router->cache_info.published_on > cutoff) // continue; - if ((((uint8_t)id_digest[0]) % 128) == ctr) { + if ((((uint8_t)id_digest[0]) % REACHABILITY_MODULO_PER_TEST) == ctr) { dirserv_single_reachability_test(now, router); } } SMARTLIST_FOREACH_END(router); - ctr = (ctr + 1) % 128; /* increment ctr */ + ctr = (ctr + 1) % REACHABILITY_MODULO_PER_TEST; /* increment ctr */ }

/** Given a fingerprint <b>fp</b> which is either set if we're looking for a diff --git a/src/or/dirserv.h b/src/or/dirserv.h index 56ad7a6..949482b 100644 --- a/src/or/dirserv.h +++ b/src/or/dirserv.h @@ -12,6 +12,14 @@ #ifndef _TOR_DIRSERV_H #define _TOR_DIRSERV_H

+/** What fraction (1 over this number) of the relay ID space do we + * (as a directory authority) launch connections to at each reachability + * test? */ +#define REACHABILITY_MODULO_PER_TEST 128 + +/** How many seconds apart are the reachability tests for a given relay? */ +#define REACHABILITY_TEST_PERIOD (10*REACHABILITY_MODULO_PER_TEST) + /** Maximum length of an exit policy summary. */ #define MAX_EXITPOLICY_SUMMARY_LEN 1000

diff --git a/src/or/main.c b/src/or/main.c index 979a2be..558608e 100644 --- a/src/or/main.c +++ b/src/or/main.c @@ -962,8 +962,9 @@ run_scheduled_events(time_t now) if (accounting_is_enabled(options)) accounting_run_housekeeping(now);

- if (now % 10 == 0 && (authdir_mode_tests_reachability(options)) && - !we_are_hibernating()) { + if (now % REACHABILITY_TEST_PERIOD/REACHABILITY_MODULO_PER_TEST == 0 && + (authdir_mode_tests_reachability(options)) && + !we_are_hibernating()) { /* try to determine reachability of the other Tor relays */ dirserv_test_reachability(now); }