[tor-bugs] #25534 [Core Tor/Tor]: Reachability of fallback directories

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#25534: Reachability of fallback directories
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 Reporter:  anadahz                          |          Owner:  (none)
     Type:  enhancement                      |         Status:  closed
 Priority:  Medium                           |      Milestone:
Component:  Core Tor/Tor                     |        Version:
 Severity:  Normal                           |     Resolution:  implemented
 Keywords:  reachability, tcp connect, ooni  |  Actual Points:
Parent ID:  #24818                           |         Points:
 Reviewer:                                   |        Sponsor:
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Changes (by teor):

 * status:  new => closed
 * resolution:   => implemented
 * parent:   => #24818


Comment:

 Replying to [comment:5 anadahz]:
 > Replying to [comment:3 nickm]:
 > > Terminology note: these are "fallback directories", not "fallback
 directory authorities".
 >
 > Thanks for the terminology note, updated the ticket accordingly.
 >
 > > Should this be an Ooni ticket? It doesn't seem to be something we can
 address in Core Tor...
 >
 > Perhaps the contents of `fallback_dirs.inc` should be populated in a
 format (ticket:25534#comment:2) that can be added directly to ooni-
 resources repository ([https://github.com/OpenObservatory/ooni-
 resources/blob/master/bridge_reachability/tor-bridges-ip-port.csv|bridge
 reachability input list]). Having such a format ensures that we are going
 to have the input list up to date. Ideally this should also happen to the
 bridges (at least the ones listed in Tor Browser), directory authorities
 are not changing that often.

 No, we don't provide custom fallback formats for each downstream consumer.
 Instead, we have a spec that can be used to parse the list:
 https://gitweb.torproject.org/torspec.git/tree/dir-list-spec.txt

 The fallback file is currently used by Stem and Metrics (Relay Search).
 OONI can use it as well.
 It should be very easy to parse the IPv4 address, DirPort (HTTP/TCP), and
 ORPort (TLS/TCP), and the IPv6 address and ORPort (TLS/TCP).

 I recommend you use the fingerprint as the "nickname", because fallback
 nicknames are not guaranteed to be unique.

 In future, we will make the authorities file into a separate list
 (#24854), and change the format so it's easy to parse (#24818). We also
 want to change the fallback format so it matches the authority format
 (#24852).

 > The relevant OONI ticket: https://github.com/OpenObservatory/ooni-
 resources/issues/11

 I don't think there is anything that core tor needs to do to make this
 happen, so I'm closing the ticket.
 (Tor Browser's default bridges are maintained by the Tor Browser team. You
 should probably parse Tor Browser's bridges file as well.)

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25534#comment:6>
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