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

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#28942: Evaluate pion WebRTC
--------------------------------------------+------------------------------
 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):

 Replying to [comment:46 cohosh]:
 > Update on this: I tried building with pion/webrtc v2.0.23 (using
 pion/sctp v1.6.4 and otherwise sticking to the versions specified in
 `go.mod` for webrtc v2.0.23) and it bootstraps fully.

 I tried this hint here:
  * [https://gitweb.torproject.org/user/dcf/tor-browser-build.git/log/?h
 =pion-webrtc&id=6bfc0beea25295c04cb9a1753ea0a433786500e4 pion-webrtc]
 branch
  * https://people.torproject.org/~dcf/pt-bundle/tor-browser-pion-
 webrtc-20190901-6bfc0beea2/

 However it still doesn't work for me :/ Maybe I misunderstood what you
 suggested. I re-ran the [attachment:gomodtorbm gomodtorbm] script with
 pion-webrtc at v2.0.23 and restored the manual fixups. Then I singularly
 upgraded pion-sctp to v1.6.4. You can see exactly the changes
 [https://gitweb.torproject.org/user/dcf/tor-browser-build.git/commit/?h
 =pion-webrtc&id=6bfc0beea25295c04cb9a1753ea0a433786500e4 here]. Does it
 look right?

 It's also possible there's something wrong with my local network setup.
 Can someone try one of the bundles in https://people.torproject.org/~dcf
 /pt-bundle/tor-browser-pion-webrtc-20190901-6bfc0beea2/ and see if it
 works? The log output I get is different from what I got in comment:43 and
 comment:45. No data flows after the initial `Buffered X bytes --> WebRTC`.
 {{{
 2019/08/31 18:35:51 Negotiating via BrokerChannel...
 Target URL:  snowflake-broker.azureedge.net
 Front URL:   ajax.aspnetcdn.com
 2019/08/31 18:35:52 SOCKS accepted:  {[scrubbed]  map[]}
 2019/08/31 18:35:52 BrokerChannel Response:
 200 OK

 2019/08/31 18:35:52 Received Answer.
 2019/08/31 18:35:52 ---- Handler: snowflake assigned ----
 2019/08/31 18:35:53 Buffered 322 bytes --> WebRTC
 2019/08/31 18:35:58 Traffic Bytes (in|out): 0 | 322 -- (0 OnMessages, 1
 Sends)
 2019/08/31 18:36:02 WebRTC: At capacity [1/1]  Retrying in 10 seconds...
 2019/08/31 18:36:12 WebRTC: At capacity [1/1]  Retrying in 10 seconds...
 2019/08/31 18:36:22 WebRTC: At capacity [1/1]  Retrying in 10 seconds...
 2019/08/31 18:36:23 WebRTC: No messages received for 30 seconds -- closing
 stale connection.
 2019/08/31 18:36:23 WebRTC: closing PeerConnection
 2019/08/31 18:36:23 WebRTC: Closing
 2019/08/31 18:36:23 copy loop ended
 2019/08/31 18:36:23 ---- Handler: closed ---
 2019/08/31 18:36:23 SOCKS listening...
 2019/08/31 18:36:23 synthesizing SIGTERM because of stdin close
 2019/08/31 18:36:23 WebRTC: melted all 0 snowflakes.
 2019/08/31 18:36:23 snowflake is done.
 }}}

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28942#comment:49>
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