STUN / STUNS uris with a "transport" parameter are rejected

For a stun ICE server such as stun:global.stun.twilio.com:3478?transport=udp The regex in rtcicetransport.py is not relaxed enough…

[2019-03-20 13:06:35,713] [relay.eventing] [ERROR] Event Listener Exception [message]:
Traceback (most recent call last)
10. File "/home/mayfield/project/librelay-python/relay/eventing.py", line 45, in dispatchEvent
      await r
9.  File "/home/mayfield/project/relay-calling-sfu/relay_calling_sfu/main.py", line 115, in onMessage
      await self.controlHandlers[control](exchange)
8.  File "/home/mayfield/project/relay-calling-sfu/relay_calling_sfu/main.py", line 154, in onCallOffer
      await call.addPeerOffer(exchange)
7.  File "/home/mayfield/project/relay-calling-sfu/relay_calling_sfu/call.py", line 191, in addPeerOffer
      await pc.setRemoteDescription(offer)
6.  File "/usr/local/lib64/python3.6/site-packages/aiortc/rtcpeerconnection.py", line 660, in setRemoteDescription
      transceiver = self.__createTransceiver(direction='recvonly', kind=media.kind)
5.  File "/usr/local/lib64/python3.6/site-packages/aiortc/rtcpeerconnection.py", line 834, in __createTransceiver
      dtlsTransport = self.__createDtlsTransport()
4.  File "/usr/local/lib64/python3.6/site-packages/aiortc/rtcpeerconnection.py", line 812, in __createDtlsTransport
      iceGatherer = RTCIceGatherer(iceServers=self.__configuration.iceServers)
3.  File "/usr/local/lib64/python3.6/site-packages/aiortc/rtcicetransport.py", line 147, in __init__
      ice_kwargs = connection_kwargs(iceServers)
2.  File "/usr/local/lib64/python3.6/site-packages/aiortc/rtcicetransport.py", line 73, in connection_kwargs
      parsed = parse_stun_turn_uri(uri)
1.  File "/usr/local/lib64/python3.6/site-packages/aiortc/rtcicetransport.py", line 115, in parse_stun_turn_uri
      raise ValueError('malformed uri')
ValueError: malformed uri

The regex for TURN servers includes support for the transport query arg, but stun does not.

[lgrahl]

That way of thinking is a bit twisted. aiortc doesn’t suffer from following standards. Twilio does from not following them. There’s absolutely no guarantee that Firefox, or the whole swath of webrtc.org based implementations, keep support for this proprietary extension. To be precise, webrtc.org just ignores the transport parameter - it doesn’t comply with it. I wouldn’t even count on a PSA for a fix for that, so it could break for them any day.

[mayfield]

I already added a workaround and I understand the position being taken. But keep in mind you’re on a short list of webrtc implementations that don’t tolerate this; iOS, Android, Safari, Firefox and Chromium accept/ignore the extrainious query args.

It’s unlikely twilio will change, so aiortc is the one that suffers.

On Sun, Mar 24, 2019 at 1:05 PM Jeremy Lainé [e-mail] wrote:

We’re not the only ones who have come to the conclusion that Twilio’s URL are not RFC-conformant:

onsip/SIP.js#117 https://github.com/onsip/SIP.js/issues/117

I don’t plan to add hacks for such URLs in aiortc so your best option is to drop the query string from the STUN/STUNS uris you receive from Twilio. If you’re a Twilio customer I also suggest you open an issue with them so they can fix it.

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