Initial HTTP/3 implementationhttp3

This includes Websocket over HTTP/3.

Since quicer, which provides the QUIC implementation,
is a NIF, Cowboy cannot depend directly on it. In order
to enable QUIC and HTTP/3, users have to set the
COWBOY_QUICER environment variable:

  export COWBOY_QUICER=1

In order to run the test suites, the same must be done
for Gun:

  export GUN_QUICER=1

HTTP/3 support is currently not available on Windows
due to compilation issues of quicer which have yet to
be looked at or resolved.

HTTP/3 support is also unavailable on the upcoming
OTP-27 due to compilation errors in quicer dependencies.
Once resolved HTTP/3 should work on OTP-27.

Because of how QUIC currently works, it's possible
that streams that get reset after sending a response
do not receive that response. The test suite was
modified to accomodate for that. A future extension
to QUIC will allow us to gracefully reset streams.

This also updates Erlang.mk.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/cowboy_stream_h.erl b/src/cowboy_stream_h.erl
index 842bd8d..b373344 100644
--- a/src/cowboy_stream_h.erl
+++ b/src/cowboy_stream_h.erl
@@ -151,6 +151,11 @@ info(StreamID, Exit={'EXIT', Pid, {Reason, Stacktrace}}, State=#state{ref=Ref, p
 				[Ref, self(), StreamID, Pid, Reason, Stacktrace]}
 			|Commands0]
 	end,
+	%% @todo We are trying to send a 500 response before resetting
+	%%       the stream. But due to the way the RESET_STREAM frame
+	%%       works in QUIC the data may be lost. The problem is
+	%%       known and a draft RFC exists at
+	%%       https://www.ietf.org/id/draft-ietf-quic-reliable-stream-reset-03.html
 	do_info(StreamID, Exit, [
 		{error_response, 500, #{<<"content-length">> => <<"0">>}, <<>>}
 	|Commands], State);