commit 2c8c58ab2fe7d452d06abdb7328be7eae658bcc0 Author: Nick Mathewson nickm@torproject.org Date: Wed Nov 30 09:04:34 2016 -0500
Another tweak for guard restrictions: don't let complete circs block
If a complete circuit C2 doesn't obey the restrictions of C1, then C2 cannot block C1.
The patch here is a little big-ish, since we can no longer look through all the complete circuits and all the waiting circuits on a single pass: we have to find the best waiting circuit first. --- src/or/entrynodes.c | 43 +++++++++++++++++++++++-------------------- 1 file changed, 23 insertions(+), 20 deletions(-)
diff --git a/src/or/entrynodes.c b/src/or/entrynodes.c index 9b38641..02ed924 100644 --- a/src/or/entrynodes.c +++ b/src/or/entrynodes.c @@ -2214,8 +2214,8 @@ entry_guards_upgrade_waiting_circuits(guard_selection_t *gs,
int n_waiting = 0; int n_complete = 0; + int n_complete_blocking = 0; origin_circuit_t *best_waiting_circuit = NULL; - origin_circuit_t *best_complete_circuit = NULL; smartlist_t *all_circuits = smartlist_new(); SMARTLIST_FOREACH_BEGIN(all_circuits_in, origin_circuit_t *, circ) { // We filter out circuits that aren't ours, or which we can't @@ -2241,12 +2241,6 @@ entry_guards_upgrade_waiting_circuits(guard_selection_t *gs, circ_state_has_higher_priority(circ, NULL, best_waiting_circuit)) { best_waiting_circuit = circ; } - } else if (state->state == GUARD_CIRC_STATE_COMPLETE) { - ++n_complete; - if (! best_complete_circuit || - circ_state_has_higher_priority(circ, NULL, best_complete_circuit)) { - best_complete_circuit = circ; - } } } SMARTLIST_FOREACH_END(circ);
@@ -2262,19 +2256,28 @@ entry_guards_upgrade_waiting_circuits(guard_selection_t *gs, const entry_guard_restriction_t *rst_on_best_waiting = origin_circuit_get_guard_state(best_waiting_circuit)->restrictions;
- if (best_complete_circuit) { - if (circ_state_has_higher_priority(best_complete_circuit, - rst_on_best_waiting, - best_waiting_circuit)) { - /* "If any circuit is <complete>, then do not use any - <waiting_for_better_guard> or <usable_if_no_better_guard> circuits - circuits whose guards have lower priority." */ - log_debug(LD_GUARD, "Considered upgrading guard-stalled circuits: found " - "%d complete and %d guard-stalled. At least one complete " - "circuit had higher priority, so not upgrading.", - n_complete, n_waiting); - goto no_change; - } + /* First look at the complete circuits: Do any block this circuit? */ + SMARTLIST_FOREACH_BEGIN(all_circuits, origin_circuit_t *, circ) { + circuit_guard_state_t *state = origin_circuit_get_guard_state(circ); + if BUG((state == NULL)) + continue; + if (state->state != GUARD_CIRC_STATE_COMPLETE) + continue; + ++n_complete; + if (circ_state_has_higher_priority(circ, rst_on_best_waiting, + best_waiting_circuit)) + ++n_complete_blocking; + } SMARTLIST_FOREACH_END(circ); + + if (n_complete_blocking) { + /* "If any circuit is <complete>, then do not use any + <waiting_for_better_guard> or <usable_if_no_better_guard> circuits + circuits whose guards have lower priority." */ + log_debug(LD_GUARD, "Considered upgrading guard-stalled circuits: found " + "%d complete and %d guard-stalled. At least one complete " + "circuit had higher priority, so not upgrading.", + n_complete, n_waiting); + goto no_change; }
/* "If any circuit is <waiting_for_better_guard>, and every currently