support domain name besides IP sent to the client in ICE candidates

Summary

support domain name besides IP sent to the client in ICE candidates

Motivation

This would allow specify the external domain sent to the client's browser, and the ip should be resolved on the client side to increase flexibility

Describe alternatives you've considered

A clear and concise description of the alternative solutions you've considered.

Additional context

ice/external_ip_mapper.go

Line 12 in 753c2a0

ip := net.ParseIP(ipStr)

[Sean-Der]

Sounds good to me!

@Rambling2076 are you interested in implementing this? Happy to help however I can :)

I would implement this like mDNS maybe? Do the resolution/lookup asynchronous?

@Sean-Der i really hope i could but i am not familiar with go
also i couldn't find where this string goes to the client's browser

[fippo]

note that this was removed from RFC 8839 (mdns is allowed by an extension spec). Lots of complexity...

[aler9]

I used domain names as SDP candidates for a while by mungling SDP and manually adding them. I stopped doing that as soon as i discovered that Chrome is the only browser that supports domain names in the SDP. In all others, domain names are reserved for mdns. This is quite clear if you take a look at Firefox's source code. Browsers will never be updated to support this feature, especially if it has been removed from the RFC.

Just solve domains on server-side and send resolved IPs to users.

[JoTurk]

I think we shouldn't have an issue with merging a support for this if someone has a use for them and want to send a patch, pion/ICE is used a lot outside of the webrtc world.