Re: [MMUSIC] Please Read and Comment: Re: ICE SDP/JSEP peace accords

[Christer Holmberg <[e-mail]>]

Hi,

>Yeah, so that's a one-character typo that made it from JSEP into both codebases.
>Firefox is fixed now (as of Firefox 66 [1]), and the editor's copy of JSEP is as well [2].

Did that also fix the parsing issue Roman mentioned?

Regards,

Christer

[1] https://hg.mozilla.org/mozilla-central/rev/34476dc321b5
[2] https://github.com/rtcweb-wg/jsep/pull/861/files


On 1/22/19 2:51 PM, Roman Shpount wrote:
On Tue, Jan 22, 2019 at 3:36 PM Christer Holmberg <[e-mail]<mailto:[e-mail]>> wrote:

I think Roman requested information about what exactly has been implemented.


We have discussed this with Adam Roach off-list.

Currently both Chrome and Firefox use outdated protocol TCP/TLS/RTP/SAVPF instead of TCP/DTLS/RTP/SAVPF which is defined in rfc7850 Section 3.5 (https://tools.ietf.org/html/rfc7850#section-3.5).

Chromium Code Search:

https://cs.chromium.org/search/?q=TCP/DTLS/RTP/SAVPF&sq=package:chromium&type=cs

Your search - TCP/DTLS/RTP/SAVPF - did not match any documents.

https://cs.chromium.org/search/?q=TCP/TLS/RTP/SAVPF&sq=package:chromium&type=cs

src/third_party/webrtc/pc/media_session.cc
 cricket::IsDtlsRtp
    81: // Most-likely values first.
    82: return protocol == "UDP/TLS/RTP/SAVPF" || protocol == "TCP/TLS/RTP/SAVPF" ||
    83:        protocol == "UDP/TLS/RTP/SAVP" || protocol == "TCP/TLS/RTP/SAVP";

src/third_party/webrtc/pc/media_session_unittest.cc
   230: static const char* kMediaProtocolsDtls[] = {
   231:     "TCP/TLS/RTP/SAVPF", "TCP/TLS/RTP/SAVP", "UDP/TLS/RTP/SAVPF",
   232:     "UDP/TLS/RTP/SAVP"};

Firefox Code Search:

https://dxr.mozilla.org/mozilla-central/search?q=TCP%2FDTLS%2FRTP%2FSAVPF
0 results from the mozilla-central tree

https://dxr.mozilla.org/mozilla-central/search?q=TCP%2FTLS%2FRTP%2FSAVPF
media/webrtc/signaling/src/sdp/SdpMediaSection.h
57 kTcpTlsRtpSavpf,    // TCP/TLS/RTP/SAVPF [JSEP-TBD]
264 return os << "TCP/TLS/RTP/SAVPF";

media/webrtc/signaling/src/sdp/rsdparsa/src/media_type.rs<http://media_type.rs>
272 "TCP/TLS/RTP/SAVPF" => SdpProtocolValue::TcpTlsRtpSavpf,

media/webrtc/signaling/src/sdp/sipcc/sdp_main.c
273 {"TCP/TLS/RTP/SAVPF", sizeof("TCP/TLS/RTP/SAVPF")},

This means both Chrome and Firefox never generate SDP with TCP/DTLS/RTP/SAVPF. In fact, neither browser currently can parse SDP with  TCP/DTLS/RTP/SAVPF and as a result they are not compliant with JSEP 5.1.2 (https://tools.ietf.org/html/draft-ietf-rtcweb-jsep-25#section-5.1.2). So, JSEP section 5.1.2 does not actually describe current implementations and both Chrome and Firefox would need to be updated to be compliant with this section of JSEP draft.

I would think that since both Chrome and Firefox would need to be updated to be compliant with JSEP section 5.1.2 anyway, it should be possible to update section 5.1.2 and clarify that it only applies to the offers during ICE restart.

Regards,
_____________
Roman Shpount