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Backend for upgrading 'waiting' circuits to 'complete'
When a nonprimary guard's circuit is complete, we don't call it actually usable until we are pretty sure that every better guard is indeed not going to give us a working circuit.
This commit is contained in:
Nick Mathewson
parent
dd6bdab3f6
commit
36e9fbd752
@ -1377,6 +1377,33 @@ entry_guards_all_primary_guards_are_down(guard_selection_t *gs)
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return 1;
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}
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/** Wrapper for entry_guard_has_higher_priority that compares the
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* guard-priorities of a pair of circuits. */
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static int
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circ_state_has_higher_priority(origin_circuit_t *a,
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origin_circuit_t *b)
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{
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circuit_guard_state_t *state_a = origin_circuit_get_guard_state(a);
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circuit_guard_state_t *state_b = origin_circuit_get_guard_state(b);
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tor_assert(state_a);
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tor_assert(state_b);
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entry_guard_t *guard_a = entry_guard_handle_get(state_a->guard);
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entry_guard_t *guard_b = entry_guard_handle_get(state_b->guard);
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if (! guard_a) {
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/* Unknown guard -- never higher priority. */
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return 0;
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} else if (! guard_b) {
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/* Known guard -- higher priority than any unknown guard. */
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return 1;
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} else {
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/* Both known -- compare.*/
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return entry_guard_has_higher_priority(guard_a, guard_b);
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}
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}
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/**
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* Look at all of the origin_circuit_t * objects in <b>all_circuits</b>,
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* and see if any of them that were previously not ready to use for
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@ -1397,25 +1424,116 @@ entry_guards_upgrade_waiting_circuits(guard_selection_t *gs,
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if (! entry_guards_all_primary_guards_are_down(gs)) {
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/* We only upgrade a waiting circuit if the primary guards are all
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* down. */
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log_debug(LD_GUARD, "Considered upgrading guard-stalled circuits, "
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"but not all primary guards were definitely down.");
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return 0;
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}
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/* XXXX finish implementing. prop271 */
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int n_waiting = 0;
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int n_complete = 0;
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origin_circuit_t *best_waiting_circuit = NULL;
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origin_circuit_t *best_complete_circuit = NULL;
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SMARTLIST_FOREACH_BEGIN(all_circuits, origin_circuit_t *, circ) {
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circuit_guard_state_t *state = origin_circuit_get_guard_state(circ);
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if (state == NULL)
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continue;
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if (state->state == GUARD_CIRC_STATE_WAITING_FOR_BETTER_GUARD) {
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++n_waiting;
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if (! best_waiting_circuit ||
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circ_state_has_higher_priority(circ, best_waiting_circuit)) {
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best_waiting_circuit = circ;
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}
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} else if (state->state == GUARD_CIRC_STATE_COMPLETE) {
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++n_complete;
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if (! best_complete_circuit ||
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circ_state_has_higher_priority(circ, best_complete_circuit)) {
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best_complete_circuit = circ;
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}
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}
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} SMARTLIST_FOREACH_END(circ);
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if (! best_waiting_circuit) {
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log_debug(LD_GUARD, "Considered upgrading guard-stalled circuits, "
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"but didn't find any.");
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return 0;
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}
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if (best_complete_circuit) {
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if (circ_state_has_higher_priority(best_complete_circuit,
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best_waiting_circuit)) {
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/* "If any circuit is <complete>, then do not use any
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<waiting_for_better_guard> or <usable_if_no_better_guard> circuits
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circuits whose guards have lower priority." */
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log_debug(LD_GUARD, "Considered upgrading guard-stalled circuits: found "
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"%d complete and %d guard-stalled. At least one complete "
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"circuit had higher priority, so not upgrading.",
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n_complete, n_waiting);
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/* XXXX prop271 implement: "(Time them out after a
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{NONPRIMARY_GUARD_IDLE_TIMEOUT} seconds.)"
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*/
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return 0;
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}
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}
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/* "If any circuit is <waiting_for_better_guard>, and every currently
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{is_pending} circuit whose guard has higher priority has been
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in state <usable_if_no_better_guard> for at least
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{NONPRIMARY_GUARD_CONNECT_TIMEOUT} seconds, and all primary
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guards have reachable status of <no>, then call that circuit
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<complete>."
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*/
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{is_pending} circuit whose guard has higher priority has been in
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state <usable_if_no_better_guard> for at least
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{NONPRIMARY_GUARD_CONNECT_TIMEOUT} seconds, and all primary guards
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have reachable status of <no>, then call that circuit <complete>."
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/* "If any circuit is <complete>, then do not use any
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<waiting_for_better_guard> or <usable_if_no_better_guard> circuits
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circuits whose guards have lower priority. (Time them out
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after a {NONPRIMARY_GUARD_IDLE_TIMEOUT} seconds.)"
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XXXX --- prop271 deviation. there's no such thing in the spec as
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an {is_pending circuit}; fix the spec.
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*/
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return 0;
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int n_blockers_found = 0;
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const time_t state_set_at_cutoff =
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approx_time() - NONPRIMARY_GUARD_CONNECT_TIMEOUT;
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SMARTLIST_FOREACH_BEGIN(all_circuits, origin_circuit_t *, circ) {
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circuit_guard_state_t *state = origin_circuit_get_guard_state(circ);
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if (state == NULL)
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continue;
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if (state->state != GUARD_CIRC_STATE_USABLE_IF_NO_BETTER_GUARD)
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continue;
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if (state->state_set_at > state_set_at_cutoff &&
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circ_state_has_higher_priority(circ, best_waiting_circuit))
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++n_blockers_found;
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} SMARTLIST_FOREACH_END(circ);
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if (n_blockers_found) {
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log_debug(LD_GUARD, "Considered upgrading guard-stalled circuits: found "
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"%d guard-stalled, but %d pending circuit(s) had higher "
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"guard priority, so not upgrading.",
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n_waiting, n_blockers_found);
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return 0;
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}
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/* Okay. We have a best waiting circuit, and we aren't waiting for
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anything better. Add all circuits with that priority to the
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list, and call them COMPLETE. */
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int n_succeeded = 0;
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SMARTLIST_FOREACH_BEGIN(all_circuits, origin_circuit_t *, circ) {
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circuit_guard_state_t *state = origin_circuit_get_guard_state(circ);
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if (state == NULL)
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continue;
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if (state->state != GUARD_CIRC_STATE_WAITING_FOR_BETTER_GUARD)
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continue;
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if (circ_state_has_higher_priority(best_waiting_circuit, circ))
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continue;
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state->state = GUARD_CIRC_STATE_COMPLETE;
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state->state_set_at = approx_time();
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smartlist_add(newly_complete_out, circ);
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++n_succeeded;
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} SMARTLIST_FOREACH_END(circ);
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log_info(LD_GUARD, "Considered upgrading guard-stalled circuits: found "
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"%d guard-stalled, %d complete. %d of the guard-stalled "
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"circuit(s) had high enough priority to upgrade.",
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n_waiting, n_complete, n_succeeded);
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tor_assert_nonfatal(n_succeeded >= 1);
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return 1;
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}
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/**
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@ -1669,7 +1787,6 @@ __attribute__((noreturn)) void
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entry_guards_DUMMY_ENTRY_POINT(void)
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{
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// prop271 XXXXX kludge; remove this
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entry_guard_has_higher_priority(NULL, NULL);
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entry_guard_encode_for_state(NULL);
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entry_guard_parse_from_state(NULL);
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tor_assert(0);
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