[tor-bugs] #24392 [Core Tor/Tor]: Ignore cached bridge descriptors until we check if they are running

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#24392: Ignore cached bridge descriptors until we check if they are running
-------------------------------------------------+-------------------------
 Reporter:  teor                                 |          Owner:  nickm
     Type:  defect                               |         Status:
                                                 |  needs_review
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.3.2.x-final
Component:  Core Tor/Tor                         |        Version:  Tor:
                                                 |  0.3.2.1-alpha
 Severity:  Normal                               |     Resolution:
 Keywords:  regression, tor-bridge-client,       |  Actual Points:  0.5
  s8-errors, review-group-27                     |
Parent ID:  #24367                               |         Points:  0.3
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------
Changes (by teor):

 * status:  needs_revision => needs_review
 * actualpoints:  0.3 => 0.5


Comment:

 Replying to [comment:5 arma]:
 > I'm stuck in a maze of twisty little tickets, all being parents of each
 other, but: in proposed commit 690f646bf:
 >
 > {{{
 > diff --git a/src/or/circuituse.c b/src/or/circuituse.c
 > index aa0df95..8c9859b 100644
 > --- a/src/or/circuituse.c
 > +++ b/src/or/circuituse.c
 > @@ -2084,7 +2084,7 @@ circuit_get_open_circ_or_launch(entry_connection_t
 *conn,
 >                 "used client functionality lately" :
 >                 "received a consensus with exits",
 >                 options->UseBridges ? "bridges" : "entrynodes");
 > -      } else if (!options->UseBridges ||
 any_bridge_descriptors_known()) {
 > +      } else if (!options->UseBridges || num_bridges_usable() > 0) {
 >          log_fn(severity, LD_APP|LD_DIR,
 >                 "Application request when we haven't %s. "
 >                 "Optimistically trying directory fetches again.",
 > }}}
 >
 > teor, did you check that you didn't break this functionality? We have
 broken it several times in the past and taken years to notice.

 You'll love this one, arma.

 It is impossible to break this functionality by changing that condition,
 because !options->UseBridges is always true at this point in the code.

 For an explanation, see the commit message on:
 {{{
 [bug24367_032 e9cb0cd7c8] Simplify some conditionals in
 circuit_get_open_circ_or_launch()
 }}}

 I also added a flag to num_bridges_usable() that lets us count "definitely
 reachable" and "maybe reachable or definitely reachable" bridges. I think
 that deals with some of the issues in #24367:

 {{{
 [bug24367_032 bca43d548a] Make sure bridges are definitely running before
 delaying directory fetches
 }}}

 We might still be missing a call to download_status_reset() somewhere, but
 I had a quick look, and it seemed ok.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24392#comment:13>
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