Add DSCP on RTP audio packets in SIP plugin

[GerardM22]

To complete #2055, I propose to do the same thing in the RTP audio packets sent by the SIP plugin.
Tested OK on my implementation of Janus server.

[januscla]

Thanks for your contribution, @GerardM22! Please make sure you sign our CLA, as it's a required step before we can merge this.

[lminiero]

Why only audio?

[GerardM22]

We only use audio in our Janus server but I can do the same thing for video.
I see that there are 4 types of stream in the SIP plugin:

• RTP audio
• RTP video
• RTCP audio
• RTCP video
  Do you think that it can be useful to do it for RTCP too or only for RTP ?

[lminiero]

No idea if RTCP should have the same value: if you know what's typical in the industry you can try doing the same. But I'd definitely add an option for RTP video too. And there should probably a check on the setsockopt call: if that fails there should be at least a warning in the logs.

[lminiero]

Any chance you can do the same for the NoSIP plugin too, now that you're at it since they're "related" as plugins and media-wise do many things the same way? Thanks!

PS: please don't forget about signing the CLA, as we can't merge otherwise.

[GerardM22]

I added DSCP setting on video RTP socket in the the SIP plugin and the check of setsockopt as you suggested but I tested only the audio.
I think its not necessary to do it for RTCP sockets.
I never looked at the NoSIP plugin, so I prefer not to touch it for the moment.

[lminiero]

I added DSCP setting on video RTP socket in the the SIP plugin and the check of setsockopt as you suggested but I tested only the audio.
I think its not necessary to do it for RTCP sockets.

Thanks!

I never looked at the NoSIP plugin, so I prefer not to touch it for the moment.

Fair enough, I'll add it myself then. This looks fine to me, so I'll merge, thanks again 👍