Commit 2938fd3b authored by George Kadianakis's avatar George Kadianakis
Browse files

prop271: When we exhaust all guards, mark all of them for retry. 

In the past, when we exhausted all guards in our sampled set, we just
waited there till we mark a guard for retry again (usually takes 10 mins
for a primary guard, 1 hour for a non-primary guard). This patch marks
all guards as maybe-reachable when we exhaust all guards (this can
happen when network is down for some time).
parent 111c66b2

changes/bug21052

0 → 100644
+4 −0
Original line number Diff line number Diff line 
  o Minor bugfixes (client, guards):

    - Fix a bug of the new guard algorithm where tor could stall for up to 10

      minutes before retrying a guard after a long period of no network.

      Fixes bug 21052; bugfix on 0.3.0.1-alpha.

src/or/entrynodes.c

+31 −8
Original line number Diff line number Diff line
@@ -1900,7 +1900,9 @@ select_entry_guard_for_circuit(guard_selection_t *gs, 
                                                   SAMPLE_EXCLUDE_PRIMARY |

                                                   SAMPLE_EXCLUDE_PENDING);

    if (guard == NULL) {

      log_info(LD_GUARD, "Absolutely no sampled guards were available.");

      log_info(LD_GUARD, "Absolutely no sampled guards were available. "

               "Marking all guards for retry and starting from top again.");

      mark_all_guards_maybe_reachable(gs);

      return NULL;

    }

    guard->is_pending = 1;
@@ -1937,6 +1939,21 @@ entry_guards_note_guard_failure(guard_selection_t *gs, 
           entry_guard_describe(guard));

}



/* Mark <b>guard</b> as maybe reachable again. */

static void

mark_guard_maybe_reachable(entry_guard_t *guard)

{

  if (guard->is_reachable != GUARD_REACHABLE_NO) {

    return;

  }



  /* Note that we do not clear failing_since: this guard is now only

   * _maybe-reachable_. */

  guard->is_reachable = GUARD_REACHABLE_MAYBE;

  if (guard->is_filtered_guard)

    guard->is_usable_filtered_guard = 1;

}



/**

 * Called when the network comes up after having seemed to be down for

 * a while: Mark the primary guards as maybe-reachable so that we'll
@@ -1945,19 +1962,25 @@ entry_guards_note_guard_failure(guard_selection_t *gs, 
STATIC void

mark_primary_guards_maybe_reachable(guard_selection_t *gs)

{

  tor_assert(gs);



  if (!gs->primary_guards_up_to_date)

    entry_guards_update_primary(gs);



  SMARTLIST_FOREACH_BEGIN(gs->primary_entry_guards, entry_guard_t *, guard) {

    if (guard->is_reachable != GUARD_REACHABLE_NO)

      continue;

    mark_guard_maybe_reachable(guard);

  } SMARTLIST_FOREACH_END(guard);

}



    /* Note that we do not clear failing_since: this guard is now only

     * _maybe-reachable_. */

    guard->is_reachable = GUARD_REACHABLE_MAYBE;

    if (guard->is_filtered_guard)

      guard->is_usable_filtered_guard = 1;

/* Called when we exhaust all guards in our sampled set: Marks all guards as

 * maybe-reachable so that we 'll try them again. */

static void

mark_all_guards_maybe_reachable(guard_selection_t *gs)

{

  tor_assert(gs);



  SMARTLIST_FOREACH_BEGIN(gs->sampled_entry_guards, entry_guard_t *, guard) {

    mark_guard_maybe_reachable(guard);

  } SMARTLIST_FOREACH_END(guard);

}