Active TCP candidates?

[ahaooahaz]

In some cases, I will use Pion instead of the browser as the client to push data to the server. When the server only supports tcp-type ice links, the candidate address generated by Pion needs to be an active-mode tcp address. Tried examples/ice-tcp, the current tcp candidate addresses only include passive mode addresses, and I didn’t find any configuration items that can change this.

The phenomenon I encountered is that Pion generates tcp passive candidate addresses, and the server’s candidate addresses only have tcp passive mode, and they always fail to connect.

When I use the browser as a client, it generates tcp's active mode candidates and works fine.

I guess the reason for the inability to connect may be related to the active mode and passive mode. I am sorry that I am a novice in webrtc, and I am not very clear about some underlying principles.

If Pion already supports this function, can you tell me how to make this function take effect?

Thanks.

[stv0g]

Hi @ahaooahaz,

I will move this issue to the pion/ice repo as this is ICE related.

[ashellunts]

Hi @ahaooahaz, it is not supported yet.
Here is draft PR for the feature: #565

[stv0g]

#565 has been merged. 🥳

[Sean-Der]

@ahaooahaz I just tagged v3.2.3 which has Active TCP support, would you mind testing it out. Thank you!

[ahaooahaz]

@Sean-Der @stv0g @ashellunts Great works!

I has tested publish video to TCP-only webrtc server, I can see the ICE-TCP connected, but when transport SRTP packets there always auth failed.

here is the TCP-only server logs which publish client is pion/webrtc@v3.2.3:

2023-05-19 03:04:50.473 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1018 SendPendingOutgoingDtlsData | 75 bytes of DTLS data ready to sent to the peer
2023-05-19 03:04:50.473 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1207 CheckRemoteFingerprint | valid remote fingerprint
2023-05-19 03:04:50.473 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1381 GetNegotiatedSrtpCryptoSuite | chosen SRTP crypto suite: SRTP_AEAD_AES_256_GCM 
2023-05-19 03:04:50.473 I [MediaServer] [7-event poller 3] WebRtcTransport.cpp:137 OnDtlsTransportConnected | 
2023-05-19 03:04:50.474 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1056 SetTimeout | DTLS timer set in 99ms
2023-05-19 03:04:50.490 W [MediaServer] [7-event poller 3] SrtpSession.cpp:246 DecryptSrtp | srtp_unprotect() failed:authentication failure (srtp_err_status_auth_fail)
2023-05-19 03:04:50.490 W [MediaServer] [7-event poller 3] SrtpSession.cpp:246 DecryptSrtp | srtp_unprotect() failed:authentication failure (srtp_err_status_auth_fail)

here is the TCP-only server logs which publish client is Chrome:

2023-05-19 03:09:32.697 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1456 OnSslInfo | DTLS handshake done                                                                                                     
2023-05-19 03:09:32.697 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1018 SendPendingOutgoingDtlsData | 67 bytes of DTLS data ready to sent to the peer
2023-05-19 03:09:32.697 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1207 CheckRemoteFingerprint | valid remote fingerprint                                                                                   
2023-05-19 03:09:32.697 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1381 GetNegotiatedSrtpCryptoSuite | chosen SRTP crypto suite: SRTP_AEAD_AES_256_GCM                                                      
2023-05-19 03:09:32.697 I [MediaServer] [7-event poller 3] WebRtcTransport.cpp:137 OnDtlsTransportConnected |                                                                                                         
2023-05-19 03:09:32.697 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1056 SetTimeout | DTLS timer set in 99ms                                                                                                 
2023-05-19 03:09:32.796 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1472 OnTimer | handshake is done so return                                                                                               
2023-05-19 03:09:32.846 W [MediaServer] [7-event poller 3] WebRtcTransport.cpp:923 inputRtp | unknown rtx rtp, rid:, ssrc:1590349209, codec:H264, seq:5814                                                            
2023-05-19 03:09:32.848 I [MediaServer] [7-event poller 3] WebRtcTransport.cpp:866 createRtpChannel | create rtp receiver of ssrc:1062276153, rid:, codec:H264                                                        
2023-05-19 03:09:32.850 D [MediaServer] [7-event poller 3] MediaSink.cpp:137 emitAllTrackReady | all track ready use 153ms
2023-05-19 03:09:32.850 T [MediaServer] [7-event poller 3] MediaSink.cpp:259 addMuteAudioTrack | mute aac track added
2023-05-19 03:09:32.850 I [MediaServer] [7-event poller 3] MultiMediaSourceMuxer.cpp:368 onAllTrackReady | stream: rtc://127.0.0.1:80/1/2?app=1&stream=2&type=push&session=43-72 , codec info: mpeg4-generic[8000/1/16] H264[320/180/0] 
2023-05-19 03:09:32.856 I [MediaServer] [7-event poller 3] MediaSource.cpp:523 emitEvent | 媒体注册:rtmp://__defaultVhost__/1/2
2023-05-19 03:09:32.856 I [MediaServer] [7-event poller 3] MediaSource.cpp:523 emitEvent | 媒体注册:rtsp://__defaultVhost__/1/2
2023-05-19 03:09:32.896 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1472 OnTimer | handshake is done so return
2023-05-19 03:09:33.492 D [MediaServer] [7-event poller 3] DtlsTransport.cpp:1472 OnTimer | handshake is done so return

[Sean-Der]

Hi @ahaooahaz would you please try again with v3.2.4

I believe you hit an unrelated bug. thank you!

[ahaooahaz]

@Sean-Der I changed to v3.2.4 and it works! 🥳