SDP is cut off between recieving 200 OK and the sdp event being emitted

[CameronJYoung]

Hello! Apologies if i'm putting this in the wrong place (I was going to start in the JSSIP mail group but it looks like it's been overrun with spam). I think I have a potential bug with JSSIP where the SDP being received in the 200 OK response looks to be cut off in the RTCSession "sdp" event. I'm aware it could be a problem with my SDP but I've enabled JSSIP debug logs and I can't see any errors indicating what could be wrong with the SDP itself. Here's the full logs:

jssip-logs.txt

I'm using JsSIP v3.10.1

As you can see it recieves a 200 OK for the INVITE

 SIP/2.0 200 OK
    Via: SIP/2.0/WSS REDACTEDHOSTNAME;rport=5063;received=127.0.0.1;branch=z9hG4bK3518430
    Call-ID: v853rkfqi5smr01om638
    From: <sip:+447700900040@REDACTEDHOSTNAME>;tag=58ofabaaig
    To: <sip:+447700900637@REDACTEDHOSTNAME>;tag=60586025-d850-4e85-8b33-ea3a341c49af
    CSeq: 4854 INVITE
    Server: SOMESERVER
    Allow: OPTIONS, REGISTER, SUBSCRIBE, NOTIFY, PUBLISH, INVITE, ACK, BYE, CANCEL, UPDATE, PRACK, MESSAGE, REFER
    Contact: <sip:28.164.90.240:5061>
    Supported: 100rel, timer, replaces, norefersub
    Session-Expires: 90;refresher=uac
    Require: timer
    Content-Type: application/sdp
    Content-Length: 624
    
    v=0
    o=- 187479965 4 IN IP4 10.39.7.65
    s=Asterisk
    c=IN IP4 10.39.7.65
    t=0 0
    m=audio 31634 UDP/TLS/RTP/SAVPF 8 126
    a=maxptime:150
    a=mid:0
    a=rtpmap:8 PCMA/8000
    a=rtpmap:126 telephone-event/8000
    a=sendrecv
    a=rtcp:31635
    a=setup:passive
    a=fingerprint:sha-256 BB:6A:AC:45:29:0B:47:84:B8:5B:0F:0B:E6:7D:6A:0D:3B:5B:D4:02:D8:0B:E3:C5:3B:0E:04:33:FC:DD:7B:95
    a=tls-id:7f5e545994815781254afbf6e9090865
    a=ptime:20
    a=ice-ufrag:FHk2EC0f
    a=ice-pwd:WdwRwem38dwAqj5PLEbXwjpPzl
    a=ice-options:trickle
    a=candidate:rfHjyG3GnNMOgcbB 1 UDP 2130706431 10.39.7.65 31634 typ host
    a=candidate:rfHjyG3GnNMOgcbB 2 UDP 2130706430 10.39.7.65 31635 typ host
    a=end-of-candidates

And then a moment later the "sdp" event get's fired and it's missing the last line and a half

RTCSession sdp from event:


v=0
    o=- 187479965 4 IN IP4 10.39.7.65
    s=Asterisk
    c=IN IP4 10.39.7.65
    t=0 0
    m=audio 31634 UDP/TLS/RTP/SAVPF 8 126
    a=maxptime:150
    a=mid:0
    a=rtpmap:8 PCMA/8000
    a=rtpmap:126 telephone-event/8000
    a=sendrecv
    a=rtcp:31635
    a=setup:passive
    a=fingerprint:sha-256 BB:6A:AC:45:29:0B:47:84:B8:5B:0F:0B:E6:7D:6A:0D:3B:5B:D4:02:D8:0B:E3:C5:3B:0E:04:33:FC:DD:7B:95
    a=tls-id:7f5e545994815781254afbf6e9090865
    a=ptime:20
    a=ice-ufrag:FHk2EC0f
    a=ice-pwd:WdwRwem38dwAqj5PLEbXwjpPzl
    a=ice-options:trickle
    a=candidate:rfHjyG3GnNMOgcbB 1 UDP 2130706431 10.39.7.65 31634 typ host
    a=candidate:rfHjyG3GnNMOgcbB 2 UDP 2130706430 10.3

After that JSSIP sends an ACK and then a BYE with:

Reason: SIP ;cause=488; text="Not Acceptable Here"

And an error from JSSIP after it sends the bye

%cJsSIP:WARN:RTCSession %cemit "peerconnection:setremotedescriptionfailed" [error:%o]%c +0ms color: #66CC00 color: inherit DOMException: Failed to execute 'setRemoteDescription' on 'RTCPeerConnection': Failed to parse SessionDescription. a=candidate:rfHjyG3GnNMOgcbB 2 UDP 2130706430 10.3 Invalid SDP line.
        at jssip.min.js:9:157630 color: #66CC00

If it is a problem with the SDP recieved in the 200 OK it might be a good place for a more descriptive log? Any additional information needed to help let me know.

[PadScratchJohns]

Hey there,

You might have fixed this already, but this looks like packet fragmentation issues.

As per: https://datatracker.ietf.org/doc/html/rfc4459

[CameronJYoung]

Hey there,

You might have fixed this already, but this looks like packet fragmentation issues.

As per: https://datatracker.ietf.org/doc/html/rfc4459

I can't imagine it's to do with packet fragmentation as JSSIP receives the "OK 200" with the full SDP. This implies the full message has already been received. Thanks