use new crypto/tls 0-RTT API

[marten-seemann]

Proposal: golang/go#63691

An initial implementation is available in the go122-crypto-tls branch.

Update: This will be available in Go 1.23.

[marten-seemann]

https://go-review.googlesource.com/c/go/+/536935 was merged 🎉

[marten-seemann]

Currently blocked on golang/go#67401, since they locked down go:linkname too much.

[yawaramin]

For my understanding, is this the issue described in https://utcc.utoronto.ca/~cks/space/blog/programming/Go123LinknameComingProblem ?

Ie

link: github.com/quic-go/quic-go/internal/qtls: invalid reference to crypto/tls.defaultCipherSuitesTLS13

[marten-seemann]

Yes this is correct.

[marten-seemann]

The Go team merged the PR, so this new API will be available in Go 1.23.

However, we might not make use of it before Go 1.24, as the benefit of the new API is pretty minimal, especially since the Go team hasn't implement the other changes that would have been needed to avoid copying the tls.Config (see my post here: golang/go#63691 (comment)).

If we wait until Go 1.24, we don't have to deal with supporting both versions of the API, since our policy is to always support the two most recent Go versions.