## Summary
To prevent bad eyeballs and severs to be able to exhaust the quic
control flows we are adding the possibility of having a timeout
for a write operation to be acknowledged. This will prevent hanging
connections from exhausting the quic control flows, creating a DDoS.
I deliberately kept this as an unregistertimeout because that was the
intent. In the future we could change this to a UDPConnConfig if we want
to pass multiple values here.
The idea of this PR is simply to add a configurable unregister UDP
timeout.
The lucas-clemente/quic-go package moved namespaces and our branch
went stale, this new fork provides support for the new quic-go repo
and applies the max datagram frame size change.
Until the max datagram frame size support gets upstreamed into quic-go,
this can be used to unblock go 1.20 support as the old
lucas-clemente/quic-go will not get go 1.20 support.
The idle period is set to 5sec.
We now also ping every second since last activity.
This makes the quic.Connection less prone to being closed with
no network activity, since we send multiple pings per idle
period, and thus a single packet loss cannot cause the problem.
Until this PR, we were naively closing the quic.Stream whenever
the callstack for handling the request (HTTP or TCP) finished.
However, our proxy handler may still be reading or writing from
the quic.Stream at that point, because we return the callstack if
either side finishes, but not necessarily both.
This is a problem for quic-go library because quic.Stream#Close
cannot be called concurrently with quic.Stream#Write
Furthermore, we also noticed that quic.Stream#Close does nothing
to do receiving stream (since, underneath, quic.Stream has 2 streams,
1 for each direction), thus leaking memory, as explained in:
https://github.com/lucas-clemente/quic-go/issues/3322
This PR addresses both problems by wrapping the quic.Stream that
is passed down to the proxying logic and handle all these concerns.
- Vendored the capnproto library to cloudflared.
- Added capnproto schema defining application protocol.
- Added Pogs and application level read write of the protocol.
João "Pisco" Fernandes
chungthuang
Sudarsan Reddy
João Oliveirinha
Devin Carr
Nuno Diegues
Igor Postelnik
Dimitris Apostolou