[tor-bugs] #25688 [Obfuscation/Snowflake]: proxy-go is still deadlocking occasionally

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#25688: proxy-go is still deadlocking occasionally
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 Reporter:  dcf                             |          Owner:  cohosh
     Type:  defect                          |         Status:  assigned
 Priority:  Low                             |      Milestone:
Component:  Obfuscation/Snowflake           |        Version:
 Severity:  Normal                          |     Resolution:
 Keywords:  network-team-roadmap-2019-Q1Q2  |  Actual Points:
Parent ID:                                  |         Points:  3
 Reviewer:                                  |        Sponsor:
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Comment (by cohosh):

 The fix for this is quite small:
 https://github.com/cohosh/snowflake/compare/deadlock

 It's safer to only write to answerChan after we're sure that
 dataChannelHandler (which calls retToken() on return) has been called.

 It's also worth pointing out that apparently OnICECompletel is being
 deprecated ([https://github.com/keroserene/go-
 webrtc/blob/master/peerconnection.go#L518, peerconnection.go#L518]) we are
 better off not relying on it anyway.

 I'm going to run this modified version as a proxy-go instance for a few
 days to see if it deadlocks before putting this in merge_ready.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25688#comment:12>
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