Support TCP stun/turn

[deldering]

Checklist

• Checked the issue tracker for similar issues to ensure this is not a duplicate.
• Described the feature in detail and justified the reason for the request.
• Provided specific use cases and examples.

Feature description

Currently only UDP is supported for connections. When used in restricted firewall environments this is blocked. Can we add support for turn(s) urls with TCP transport?

Use cases

Restricted firewall environments can prohibit calls.

Alternatives

No response

Additional context

No response

[TempoTian]

Yes, it’s possible, and I’ve decided to add this feature.

Compared to UDP (where a single socket can communicate with multiple remote hosts), TCP connections are strictly one-to-one. Also, ESP-IDF has a limited number of available sockets.

So if we add TCP support for STUN/TURN, we will likely need to limit the number of concurrent TCP hosts to around 3–4. This will also require creating separate threads (or an async mechanism) to handle non-blocking connections.

Would this design be suitable for your use case?

[deldering]

Do you mean that there would be a limit to the number of participants in a group call? For me the calls are all one-to-one from the device point of view so that would be no issue. I would be very happy if I could be able to use turns on port 443 for a one-to-one call