1245676 - WEBRTC InvalidSessionDescriptionError: Answer tried to set recv when offer did not set send

Status: RESOLVED INVALID

(Core :: WebRTC: Networking, defect)

Description

[j.smits.work]

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.71 Safari/537.36

Steps to reproduce:

We tried to connect conference with one way audio offer, but for Firefox was not working.

Offer constrains:
rtcOfferConstraints: {
    offerToReceiveAudio: true,
    offerToReceiveVideo: false
},

OFFER body:
v=0
o=mozilla...THIS_IS_SDPARTA-39.0 1234582256825317267 0 IN IP4 0.0.0.0
s=-
t=0 0
a=sendrecv
a=fingerprint:sha-256 78:FF:54:2C:9A:B0:DC:2B:FC:31:83:89:17:AA:33:AF:FC:EC:C5:9E:0C:8B:E4:AA:23:47:15:09:71:DD:4D:A0
a=group:BUNDLE sdparta_0
a=ice-options:trickle
a=msid-semantic:WMS *
m=audio 44686 RTP/SAVPF 109 9 0 8
c=IN IP4 x.x.x.x
a=candidate:0 1 UDP 2122252543 x.x.x.x 44686 typ host
a=candidate:0 2 UDP 2122252542 x.x.x.x 52130 typ host
a=candidate:2 1 UDP 1686110207 x.x.x.x 44686 typ srflx raddr x.x.x.x rport 44686
a=candidate:2 2 UDP 1686110206 x.x.x.x 52130 typ srflx raddr x.x.x.x rport 52130
a=recvonly
a=end-of-candidates
a=extmap:1 urn:ietf:params:rtp-hdrext:ssrc-audio-level
a=ice-pwd:06bf8e8ece7e22f262546b874e13010e
a=ice-ufrag:d0d3aae0
a=mid:sdparta_0
a=rtcp-mux
a=rtpmap:109 opus/48000/2
a=rtpmap:9 G722/8000/1
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=setup:actpass

ANSWER BODY:
v=0
o=matrix 1454436711 1454436712 IN IP4 x.x.x.x
s=matrix
c=IN IP4 x.x.x.x
t=0 0
a=msid-semantic: WMS PrZnRR78adkqAdzI3cJ4tKDYF1CojinZ
m=audio 22178 RTP/SAVPF 0
a=rtpmap:0 PCMU/8000
a=ptime:20
a=fingerprint:sha-256 56:34:DC:1D:D5:94:2B:F5:F0:BA:13:45:FD:A7:54:78:A0:BF:D0:BB:45:DD:FC:E9:D0:33:0B:88:12:DC:84:30
a=rtcp-mux
a=rtcp:22178 IN IP4 x.x.x.x
a=ssrc:4206958201 cname:zddhVagVdrcDuBco
a=ssrc:4206958201 msid:PrZnRR78adkqAdzI3cJ4tKDYF1CojinZ a0
a=ssrc:4206958201 mslabel:PrZnRR78adkqAdzI3cJ4tKDYF1CojinZ
a=ssrc:4206958201 label:PrZnRR78adkqAdzI3cJ4tKDYF1CojinZa0
a=ice-ufrag:DMiXmMLSDe7NmkDM
a=ice-pwd:nGT8GZUKgWdBogPSSXG5AiO4
a=candidate:9067675717 1 udp 659136 x.x.x.x 22178 typ host generation 0

As we see server is not sending any recv as error is showing.



Actual results:

Firefox stopped with SDP error after we tried to setRemoteDescription.

Error message:
InvalidSessionDescriptionError: Answer tried to set recv when offer did not set send





Expected results:

Technically we should be able to listen conference without calling userMedia by setting up offer constrains.

Comment 1

[Byron Campen [:bwc]]

There is no direction attribute in the answer SDP, which means the default of sendrecv holds:

From RFC 4566 Section 6, page 26
"
If none of the attributes "sendonly", "recvonly", "inactive",
and "sendrecv" is present, "sendrecv" SHOULD be assumed as the
default for sessions that are not of the conference type
"broadcast" or "H332" (see below).
"

Comment 2

[Randell Jesup [:jesup] (needinfo me)]

Valid answers to a=recvonly are a=sendonly and a=inactive.

RFC 3264: " If a media stream is
   listed as recvonly in the offer, the answer MUST be marked as
   sendonly or inactive in the answer. "