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

[Roman Shpount <[e-mail]>]

On Tue, Jan 22, 2019 at 3:36 PM Christer Holmberg <
[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Currently both Chrome and Firefox use outdated protocol TCP/TLS/RTP/SAVPF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
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