webrtc: WASM support

[youngjoon-lee]

Description

Make WebRTC works in WASM environments.

Motivation

#3875 (comment): Discussion for the needs of WebRTC WASM
#4015: WebTransport implementation for WASM which can be a reference of this issue.

Current Implementation

The current WebRTC transport in rust-libp2p works only for standalone nodes.

Are you planning to do it yourself in a pull request?

Yes, if there is no plan by libp2p team.

[thomaseizinger]

Yes, if there is no plan by libp2p team.

No plans currently but very grateful for a contribution!

[mxinden]

Yes indeed! Very grateful.

[mxinden]

Just stumbled upon rust-libp2p libp2p-wasm-ext WebRTC bindings.

https://github.com/openmina/rust-libp2p/blob/webrtc/transports/wasm-ext/src/webrtc.js

This is used in https://github.com/openmina/openmina/blob/0e0039bfdf8ae1942b029cf98740129e7847efa8/node/wasm/src/service/libp2p/mod.rs#L71-L82.

Thanks @p-shahi for surfacing this.

@binier since you have implemented the above, mind sharing some details here? Also would you be interested in upstreaming your work or help @youngjoon-lee to do so?

One small note is that we are moving away from the libp2p-wasm-ext architecture, towards individual crates using websys. See e.g #4015.

[youngjoon-lee]

Awesome. Thank you. I'll take a look at the openmina's implementation and see if I can migrate it into the websys way.

[binier]

@mxinden It's been a while since I touched that, so I don't remember all the details, but to speak to the state of the code, I'd say it's WIP and doesn't follow any specs (if there is any for webrtc transport). It works well with go-libp2p (modified), which was the goal. I won't be continuing work on that though, instead we've decided to implement and use custom protocol just based on WebRTC.

@youngjoon-lee Let me know if you'll have any questions, I'll gladly help.

[mxinden]

Cross-referencing #4248 here.

[thomaseizinger]

Closing this in favor of #4248 being merged and #4389 tracking the remaining work.