RTCDataChannel stream id never reuse

In the transport code, you never reset number to 0 if it reaches the max. https://github.com/aiortc/aiortc/blob/master/src/aiortc/rtcsctptransport.py#L1620

        if stream_id is None:
                while self._data_channel_id in self._data_channels:
                    self._data_channel_id += 2
                stream_id = self._data_channel_id
                self._data_channels[stream_id] = channel
                self._data_channel_id += 2
                channel._setId(stream_id)

it can be ok for a custom client but on the browser, we have a very strict limitation: stream_id < 1024 on Chrome and stream_id < 256 on Firefox. On the Chrome side, you can check MaxChannels param. As you can see, if I need often close and create DataChannel I very quickly reach this limitation.

Also, some details here https://github.com/w3c/webrtc-pc/issues/2158

I suppose should be a way to setup max_stream_id and try reused freed ids.

[lgrahl]

@jlaine You can reuse a stream ID of a stream that has been reset from both sides (incoming and outgoing side).

Code section in RAWRTC for reference: https://github.com/rawrtc/rawrtc-data-channel/blob/5d1105f9b852074250f2fc6c072bd7690c31fea4/src/sctp_transport/transport.c#L1070

Edit: Be aware that, at least in usrsctp, it is quite tricky to implement.

[jlaine]

Thanks @lgrahl !

@stalkerg would you mind giving the PR a try and report back whether it solves your problem?

NOTE: I am well aware there is currently no check that we have not exceeded the maximum number of allowed streams, but at least your stream IDs should get recycled.