proposal: x/net/quic: signal `unsupported` for key-update interop test

[larseggert]

Proposal Details

Based on https://interop.seemann.io/, go-x-net doesn't seem to support key updates. Please signal this to the runner by returning unsupported for this interop test case.

[ianlancetaylor]

CC @neild

[neild]

x/net/quic does support key updates. I think the problem may be that the client initiates the first update later in the connection than the interop runner wants. (After 1000 packets, and the interop test wants an update in the first megabyte of data transferred.)

[larseggert]

OK, so as far as the interop runner is concerned, that is then lack of support for the test. I'd suggest you either do the key update earlier during the test, or mark it as unsupported?

[gopherbot]

Change https://go.dev/cl/582855 mentions this issue: quic: initiate key rotation earlier in connections

[neild]

I believe this used to pass, but probably broke after https://go.dev/cl/564476, which reduces the total number of packets sent by the client in this test configuration under the 1000 packet threshold.

It's a bit weird to set the key rotation policy specifically to make this test pass, but 1000 packets is a completely arbitrary number anyway, so just always rotating earlier might be simplest.

[larseggert]

Most other clients pass the test name in via a command line option, and then configure their default behavior as needed. Might want to do that too? (Or do a special client just for interop, but might be overkill.)

[neild]

We intentionally have few configuration parameters, and the interop client uses the public package API. So the question is how we'd configure this.

Probably through a GODEBUG setting, but we don't have any GODEBUGs that adjust behavior at the moment so adding one would be a reasonably significant change.