[tor-commits] [tor/master] Split sampled_guards_update_from_consensus() into subfunctions
nickm at torproject.org
nickm at torproject.org
Mon Jul 30 12:51:07 UTC 2018
commit 86549c0d9e636dabe3a0ed9890afe3faf920b7b6
Author: rl1987 <rl1987 at 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);
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