[tor-bugs] #31100 [Circumvention/Snowflake]: Firefox addon not reporting any users

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#31100: Firefox addon not reporting any users
-------------------------------------+----------------------------------
 Reporter:  cohosh                   |          Owner:  cohosh
     Type:  defect                   |         Status:  assigned
 Priority:  Medium                   |      Milestone:  Tor: unspecified
Component:  Circumvention/Snowflake  |        Version:  Tor: unspecified
 Severity:  Normal                   |     Resolution:
 Keywords:  snowflake-webextension   |  Actual Points:
Parent ID:                           |         Points:
 Reviewer:                           |        Sponsor:  Sponsor28
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Comment (by cohosh):

 More information:

 I got it to go into an infinite loop again. This occurred when a client
 outside my network attempted to connect through my proxy. The debug logs
 show:
 {{{
 Snowflake: Broker: Successfully replied with answer. snowflake.js:1194:13
 XML Parsing Error: no element found
 Location: https://snowflake-broker.bamsoftware.com/answer
 Snowflake: At client capacity.
 ICE failed, add a STUN server and see about:webrtc for more details
 Snowflake: At client capacity.
 }}}
 And then the proxy stops polling and remains at capacity. It looks like
 the answer is received and so the proxypair is set to active, but the
 datachannel is never opened. When going to `about:webrtc` to look at my
 local candidates I see only
 {{{
 a=candidate:0 1 UDP 2122252543 192.168.1.2 58106 typ host

 a=candidate:1 1 TCP 2105524479 192.168.1.2 9 typ host tcptype active

 }}}
 which would work for a local client but not a remote one. So it seems STUN
 isn't giving non-local candidates. So there are two things that need
 fixing:
 - We should make set a timeout on datachannels opening to avoid infinite
 loops
 - We should figure out what's going wrong with STUN

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/31100#comment:10>
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