commit 86549c0d9e636dabe3a0ed9890afe3faf920b7b6 Author: rl1987 <rl1987@sdf.lonestar.org> Date: Fri Jun 22 15:21:05 2018 +0300 Split sampled_guards_update_from_consensus() into subfunctions --- src/feature/client/entrynodes.c | 123 +++++++++++++++++++++++++++++++--------- 1 file changed, 95 insertions(+), 28 deletions(-) diff --git a/src/feature/client/entrynodes.c b/src/feature/client/entrynodes.c index 664be8ce1..ee6ff8c67 100644 --- a/src/feature/client/entrynodes.c +++ b/src/feature/client/entrynodes.c @@ -406,6 +406,17 @@ get_remove_unlisted_guards_after_days(void) DFLT_REMOVE_UNLISTED_GUARDS_AFTER_DAYS, 1, 365*10); } + +/** + * Return number of seconds that will make a guard no longer eligible + * for selection if unlisted for this long. + */ +static time_t +get_remove_unlisted_guards_after_seconds(void) +{ + return get_remove_unlisted_guards_after_days() * 24 * 60 * 60; +} + /** * We remove unconfirmed guards from the sample after this many days, * regardless of whether they are listed or unlisted. @@ -1237,30 +1248,28 @@ entry_guard_is_listed,(guard_selection_t *gs, const entry_guard_t *guard)) } /** - * Update the status of all sampled guards based on the arrival of a - * new consensus networkstatus document. This will include marking - * some guards as listed or unlisted, and removing expired guards. */ -STATIC void -sampled_guards_update_from_consensus(guard_selection_t *gs) + * Enumerate <b>sampled_entry_guards</b> smartlist in <b>gs</b>. + * For each <b>entry_guard_t</b> object in smartlist, do the following: + * * Update <b>currently_listed</b> field to reflect if guard is listed + * in guard selection <b>gs</b>. + * * Set <b>unlisted_since_date</b> to approximate UNIX time of + * unlisting if guard is unlisted (randomize within 20% of + * get_remove_unlisted_guards_after_seconds()). Otherwise, + * set it to 0. + * + * Require <b>gs</b> to be non-null pointer. + * Return a number of entries updated. + */ +static size_t +sampled_guards_update_consensus_presence(guard_selection_t *gs) { - tor_assert(gs); - const int REMOVE_UNLISTED_GUARDS_AFTER = - (get_remove_unlisted_guards_after_days() * 86400); - const int unlisted_since_slop = REMOVE_UNLISTED_GUARDS_AFTER / 5; + size_t n_changes = 0; - // It's important to use only a live consensus here; we don't want to - // make changes based on anything expired or old. - if (live_consensus_is_missing(gs)) { - log_info(LD_GUARD, "Not updating the sample guard set; we have " - "no live consensus."); - return; - } - log_info(LD_GUARD, "Updating sampled guard status based on received " - "consensus."); + tor_assert(gs); - int n_changes = 0; + const time_t unlisted_since_slop = + get_remove_unlisted_guards_after_seconds() / 5; - /* First: Update listed/unlisted. */ SMARTLIST_FOREACH_BEGIN(gs->sampled_entry_guards, entry_guard_t *, guard) { /* XXXX #20827 check ed ID too */ const int is_listed = entry_guard_is_listed(gs, guard); @@ -1304,14 +1313,33 @@ sampled_guards_update_from_consensus(guard_selection_t *gs) } } SMARTLIST_FOREACH_END(guard); - const time_t remove_if_unlisted_since = - approx_time() - REMOVE_UNLISTED_GUARDS_AFTER; - const time_t maybe_remove_if_sampled_before = - approx_time() - get_guard_lifetime(); - const time_t remove_if_confirmed_before = - approx_time() - get_guard_confirmed_min_lifetime(); + return n_changes; +} + +/** + * Enumerate <b>sampled_entry_guards</b> smartlist in <b>gs</b>. + * For each <b>entry_guard_t</b> object in smartlist, do the following: + * * If <b>currently_listed</b> is false and <b>unlisted_since_date</b> + * is earlier than <b>remove_if_unlisted_since</b> - remove it. + * * Otherwise, check if <b>sampled_on_date</b> is earlier than + * <b>maybe_remove_if_sampled_before</b>. + * * When above condition is correct, remove the guard if: + * * It was never confirmed. + * * It was confirmed before <b>remove_if_confirmed_before</b>. + * + * Require <b>gs</b> to be non-null pointer. + * Return number of entries deleted. + */ +static size_t +sampled_guards_prune_obsolete_entries(guard_selection_t *gs, + const time_t remove_if_unlisted_since, + const time_t maybe_remove_if_sampled_before, + const time_t remove_if_confirmed_before) +{ + size_t n_changes = 0; + + tor_assert(gs); - /* Then: remove the ones that have been junk for too long */ SMARTLIST_FOREACH_BEGIN(gs->sampled_entry_guards, entry_guard_t *, guard) { int rmv = 0; @@ -1319,7 +1347,7 @@ sampled_guards_update_from_consensus(guard_selection_t *gs) guard->unlisted_since_date < remove_if_unlisted_since) { /* "We have a live consensus, and {IS_LISTED} is false, and - {FIRST_UNLISTED_AT} is over {REMOVE_UNLISTED_GUARDS_AFTER} + {FIRST_UNLISTED_AT} is over get_remove_unlisted_guards_after_days() days in the past." */ log_info(LD_GUARD, "Removing sampled guard %s: it has been unlisted " @@ -1355,6 +1383,45 @@ sampled_guards_update_from_consensus(guard_selection_t *gs) } } SMARTLIST_FOREACH_END(guard); + return n_changes; +} + +/** + * Update the status of all sampled guards based on the arrival of a + * new consensus networkstatus document. This will include marking + * some guards as listed or unlisted, and removing expired guards. */ +STATIC void +sampled_guards_update_from_consensus(guard_selection_t *gs) +{ + tor_assert(gs); + + // It's important to use only a live consensus here; we don't want to + // make changes based on anything expired or old. + if (live_consensus_is_missing(gs)) { + log_info(LD_GUARD, "Not updating the sample guard set; we have " + "no live consensus."); + return; + } + log_info(LD_GUARD, "Updating sampled guard status based on received " + "consensus."); + + /* First: Update listed/unlisted. */ + size_t n_changes = sampled_guards_update_consensus_presence(gs); + + const time_t remove_if_unlisted_since = + approx_time() - get_remove_unlisted_guards_after_seconds(); + const time_t maybe_remove_if_sampled_before = + approx_time() - get_guard_lifetime(); + const time_t remove_if_confirmed_before = + approx_time() - get_guard_confirmed_min_lifetime(); + + /* Then: remove the ones that have been junk for too long */ + n_changes += + sampled_guards_prune_obsolete_entries(gs, + remove_if_unlisted_since, + maybe_remove_if_sampled_before, + remove_if_confirmed_before); + if (n_changes) { gs->primary_guards_up_to_date = 0; entry_guards_update_filtered_sets(gs);