Use connect+bind

[maskit]

Since we use one socket for all QUIC connections (all QUICNetVCs share the socket), we cannot notify WRITE_READY appropriately. Currently we have a hack for this issue which reschedule WRITE_READY at the end of event handler.

If we could use connect() and bind(), each connections would have own sockets, and then we would be able to use the same mechanism as TCP connections.

[scw00]

As @oknet indicated

How does connection migrated work ? Create a new socket with REUSEPORT ?

[maskit]

I don’t have detail design, but I think we probably need to maintain two sockets during migration because the new connection (path) may not be available and we may need to migrate back to the original connection.

[zwoop]

I think, but not tested, if the you close the old FD, remaining packets ends up on the "main" socket ? So we'd still need to dispatch them. The option of keeping both up for a while also seems feasible, but for how long?

The other option Christoph had suggested would involve using eBPF to deal with the migrations (i.e. let the kernel deal with moving the packets to the new socket).

[maskit]

The option of keeping both up for a while also seems feasible, but for how long?

QUIC layer should know it and it can close either of the old one or the new one. I don’t have exact number at the moment but I think it’s a few RTT.

eBPF is definitely an option we should try. It would be great if we could support multiple ways with less ifdef.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. Marking it stale to flag it for further consideration by the community.