[tor-bugs] #11301 [Tor]: Tor does not reconnect after network loss with bridges

[Tor Bug Tracker & Wiki]

#11301: Tor does not reconnect after network loss with bridges
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 Reporter:  mikeperry                             |          Owner:  nickm
     Type:  defect                                |         Status:  new
 Priority:  major                                 |      Milestone:
Component:  Tor                                   |        Version:
 Keywords:  tor-client, tbb-usability, tbb-needs  |  Actual Points:
Parent ID:                                        |         Points:
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 Yawning and I have both noticed that tor can become unresponsive if either
 normal tor bridges or PT bridges are configured, and the client suffers a
 network connectivity loss. After sustained network connectivity loss, all
 of the orconns end up closed, and Tor will not try to reconnect to its
 bridges, even when new stream attempts arrive.

 It is possible that Tor is simply marking all of its bridges down in this
 case, and is not trying to reconnect to them when the network connectivity
 returns, thinking they are still down?

 The only way to solve this issue is to either send "SIGNAL HUP" to the
 control port, or to kill -HUP `pidof tor`. After recieving the HUP signal,
 tor immediately launches new orconns and circuits for its bridges, and
 attaches the currently pending streams to these new circuits.

 Sometimes, after this problem has happened once, tor will cease building
 circuits even if the network remains available.

 This is extremely bad for usability, because TBB becomes completely
 unusable in this case, and the only thing a normal user can do is exit the
 whole browser and re-launch it.

 This may also indicate a deeper bug with how Tor handles the
 liveness/'down' status of normal Guard nodes, and may cause Tor to rotate
 Guards more frequently than necessary.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/11301>
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