[tor-bugs] #28942 [Circumvention/Snowflake]: Evaluate pion WebRTC

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#28942: Evaluate pion WebRTC
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 Reporter:  backkem                         |          Owner:  cohosh
     Type:  enhancement                     |         Status:  accepted
 Priority:  Medium                          |      Milestone:
Component:  Circumvention/Snowflake         |        Version:
 Severity:  Normal                          |     Resolution:
 Keywords:  anti-censorship-roadmap-august  |  Actual Points:
Parent ID:                                  |         Points:  5
 Reviewer:                                  |        Sponsor:
                                            |  Sponsor28-must
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Comment (by dcf):

 I tried also with pion-webrtc
 [https://github.com/pion/webrtc/commits/v2.1.3 v2.1.3], released 5 days
 ago. With it, I get the same failure as in comment:43 with v2.1.2: not
 even a `Buffered X bytes --> WebRTC` in the log.

 I'm looking at some possibly relevant commits:
 [https://github.com/pion/webrtc/commit/7f3000d9a6eea38623833b6cac524cbf35b4238d
 Parse DTLS setup in SetRemoteDescription]::
  Take into consideration if remote is running DTLS as a client/server.
 Before we ignored this value and we could enter cases where DTLS would
 never connect. Resolves [https://github.com/pion/webrtc/issues/494 #494]
 [https://github.com/pion/webrtc/commit/4095d2cde9783be9a162765264f0ae1cb9c2ad91
 Fix for Safari and latest Firefox]::
  This fixes the echo program so it works properly on Safari and Firefox,
 where the preferred offered dynamic media type is not 96/VP8. It loads
 MediaEngine with codecs found in the offer and then uses the payload type
 of the offer's preferred video codec in the answer.

 The latter commit rearranges some API-using code in examples/echo/main.go.
 Maybe we need to do the same?

 There must be a problem either in pion-webrtc, or in the way we are using
 it. I think a good debugging step now is to make a minimal reproducing
 example (text chat between a command-line pion-webrtc program and a
 browser) and see where it is failing.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28942#comment:51>
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