WIP

src/cowboy_http3.erl

@@ -86,8 +86,9 @@
 	%% Whether the stream is currently in a special state.
 	status :: header | {unidi, control | encoder | decoder}
 		| normal | {data | ignore, non_neg_integer()} | stopping
+		| {webtransport_session, normal | {ignore, non_neg_integer()}}
 		%% @todo Is unidi | bidi useful to keep?
-		| webtransport_session | {webtransport_stream, cow_http3:stream_id(), unidi | bidi},
+		| {webtransport_stream, cow_http3:stream_id(), unidi | bidi},
 
 	%% Stream buffer.
 	buffer = <<>> :: binary(),
@@ -256,7 +257,8 @@ parse1(State=#state{http3_machine=HTTP3Machine0},
 			terminate(State#state{http3_machine=HTTP3Machine}, Error)
 	end;
 %% @todo Handle when IsFin = fin which must terminate the WT session.
-parse1(State, Stream=#stream{id=SessionID, status=webtransport_session}, Data, IsFin) ->
+parse1(State, Stream=#stream{id=SessionID, status=
+		{webtransport_session, normal}}, Data, IsFin) ->
 	case cow_capsule:parse(Data) of
 		{ok, wt_drain_session, Rest} ->
 			webtransport_event(State, SessionID, close_initiated),
@@ -274,14 +276,32 @@ parse1(State, Stream=#stream{id=SessionID, status=webtransport_session}, Data, I
 			%% @todo Don't crash, error out properly.
 			<<>> = Rest,
 			loop(webtransport_terminate_session(State, Stream));
-		%% Ignore unknown/unhandled capsules.
+		more ->
+			loop(stream_store(State, Stream#stream{buffer=Data}));
+		%% Ignore unhandled/unknown capsules.
 		{ok, _, Rest} ->
 			parse1(State, Stream, Rest, IsFin);
+		{ok, Rest} ->
+			parse1(State, Stream, Rest, IsFin);
+		%% @todo Make the max length configurable?
+		{skip, Len} when Len =< 8192 ->
+			loop(stream_store(State, Stream#stream{
+				status={webtransport_session, {ignore, Len}}}));
+		{skip, Len} ->
+			%% @todo What should be done on capsule error?
+			error({todo, capsule_too_long, Len});
 		error ->
 			%% @todo What should be done on capsule error?
-			error({todo, capsule_error, Data});
+			error({todo, capsule_error, Data})
-		more ->
+	end;
-			loop(stream_store(State, Stream#stream{buffer=Data}))
+parse1(State, Stream=#stream{status=
+		{webtransport_session, {ignore, Len}}}, Data, IsFin) ->
+	case Data of
+		<<_:Len/unit:8, Rest/bits>> ->
+			parse1(State, Stream#stream{status={webtransport_session, normal}}, Rest, IsFin);
+		_ ->
+			loop(stream_store(State, Stream#stream{
+				status={webtransport_session, {ignore, Len - byte_size(Data)}}}))
 	end;
 parse1(State, #stream{id=StreamID, status={webtransport_stream, SessionID, _}}, Data, IsFin) ->
 	webtransport_event(State, SessionID, {stream_data, StreamID, IsFin, Data}),
@@ -582,20 +602,14 @@ early_error(State0=#state{ref=Ref, opts=Opts, peer=Peer},
 
 %% Datagrams.
 
-parse_datagram(State, Data) ->
+parse_datagram(State, Data0) ->
-	case cow_http3:parse_int(Data) of
+	{SessionID, Data} = cow_http3:parse_datagram(Data0),
-		{QuarterID, Rest} ->
+	case stream_get(State, SessionID) of
-			SessionID = QuarterID * 4,
+		#stream{status={webtransport_session, _}} ->
-			case stream_get(State, SessionID) of
+			webtransport_event(State, SessionID, {datagram, Data}),
-				#stream{status=webtransport_session} ->
+			loop(State);
-					webtransport_event(State, SessionID, {datagram, Rest}),
+		_ ->
-					loop(State);
+			error(todo) %% @todo Might be a future WT session or an error.
-				_ ->
-					error(todo) %% @todo Might be a future WT session or an error.
-			end;
-		%% Ignore invalid datagrams. @todo Is that behavior correct?
-		more ->
-			loop(State)
 	end.
 
 %% Erlang messages.
@@ -774,7 +788,7 @@ commands(State0, Stream0=#stream{id=StreamID},
 	%% to terminate the stream properly.
 	HTTP3Machine = cow_http3_machine:become_webtransport_session(StreamID, HTTP3Machine0),
 	Stream = Stream1#stream{
-		status=webtransport_session,
+		status={webtransport_session, normal},
 		state={cowboy_webtransport, WTState#{stream_state => StreamState}}
 	},
 	%% @todo We must propagate the buffer to capsule handling if any.
@@ -905,7 +919,7 @@ become_webtransport_stream(State0=#state{http3_machine=HTTP3Machine0},
 
 webtransport_event(State, SessionID, Event) ->
 	#stream{
-		status=webtransport_session,
+		status={webtransport_session, _},
 		state={cowboy_webtransport, #{session_pid := SessionPid}}
 	} = stream_get(State, SessionID),
 	SessionPid ! {'$webtransport_event', Event},
@@ -913,7 +927,7 @@ webtransport_event(State, SessionID, Event) ->
 
 webtransport_commands(State, SessionID, Commands) ->
 	case stream_get(State, SessionID) of
-		Session = #stream{status=webtransport_session} ->
+		Session = #stream{status={webtransport_session, _}} ->
 			wt_commands(State, Session, Commands);
 		%% The stream has been terminated, ignore pending commands.
 		error ->
@@ -947,9 +961,8 @@ wt_commands(State, Session, [{close_stream, StreamID, Code}|Tail]) ->
 	error({todo, State, Session, [{close_stream, StreamID, Code}|Tail]});
 wt_commands(State=#state{conn=Conn}, Session=#stream{id=SessionID},
 		[{send, datagram, Data}|Tail]) ->
-	QuarterID = SessionID div 4,
 	%% @todo Add a function to cowboy_quicer.
-	case quicer:send_dgram(Conn, [cow_http3:encode_int(QuarterID), Data]) of
+	case quicer:send_dgram(Conn, cow_http3:datagram(SessionID, Data)) of
 		{ok, _} ->
 			wt_commands(State, Session, Tail)
 		%% @todo Handle errors.
@@ -1003,7 +1016,7 @@ webtransport_terminate_session(State=#state{conn=Conn, http3_machine=HTTP3Machin
 		streams=Streams0, lingering_streams=Lingering0}, #stream{id=SessionID}) ->
 	%% Reset/abort the WT streams.
 	Streams = maps:filtermap(fun
-		(_, #stream{id=StreamID, status=webtransport_session})
+		(_, #stream{id=StreamID, status={webtransport_session, _}})
 				when StreamID =:= SessionID ->
 			%% We remove the session stream but do the shutdown outside this function.
 			false;
@@ -1031,7 +1044,7 @@ stream_peer_send_shutdown(State, StreamID) ->
 	case stream_get(State, StreamID) of
 		%% Cleanly terminating the CONNECT stream is equivalent
 		%% to an application error code of 0 and empty message.
-		Stream = #stream{status=webtransport_session} ->
+		Stream = #stream{status={webtransport_session, _}} ->
 			webtransport_event(State, StreamID, {closed, 0, <<>>}),
 			%% Shutdown the CONNECT stream fully.
 			%% @todo This needs a cowboy_quicer function.
@@ -1235,7 +1248,7 @@ stream_closed(State=#state{opts=Opts,
 	case maps:take(StreamID, Streams0) of
 		%% In the WT session's case, streams will be
 		%% removed in webtransport_terminate_session.
-		{Stream=#stream{status=webtransport_session}, _} ->
+		{Stream=#stream{status={webtransport_session, _}}, _} ->
 			webtransport_event(State, StreamID, closed_abruptly),
 			webtransport_terminate_session(State, Stream);
 		{#stream{state=undefined}, Streams} ->

src/cowboy_quicer.erl

@@ -203,7 +203,7 @@ handle({quic, Data, StreamRef, #{flags := Flags}}) when is_binary(Data) ->
 	end,
 	{data, StreamID, IsFin, Data};
 %% @todo Match on Conn.
-handle({quic, Data, Conn, Flags}) when is_integer(Flags) ->
+handle({quic, Data, Conn, Flags}) when is_binary(Data), is_integer(Flags) ->
 	{datagram, Data};
 %% QUIC_CONNECTION_EVENT_PEER_STREAM_STARTED.
 handle({quic, new_stream, StreamRef, #{flags := Flags}}) ->

test/draft_h3_webtransport_SUITE.erl

@@ -130,10 +130,12 @@ application_protocol_negotiation(Config) ->
 	doc("Applications can negotiate a protocol to use via WebTransport. "
 		"(draft_webtrans_http3 3.4)"),
 	%% Connect to the WebTransport server.
+	WTAvailableProtocols = cow_http_hd:wt_available_protocols([<<"foo">>, <<"bar">>]),
 	#{
 		resp_headers := RespHeaders
-	} = do_webtransport_connect(Config, [{<<"wt-available-protocols">>, <<"foo, bar">>}]),
+	} = do_webtransport_connect(Config, [{<<"wt-available-protocols">>, WTAvailableProtocols}]),
-	{<<"wt-protocol">>, <<"foo">>} = lists:keyfind(<<"wt-protocol">>, 1, RespHeaders),
+	{<<"wt-protocol">>, WTProtocol} = lists:keyfind(<<"wt-protocol">>, 1, RespHeaders),
+	<<"foo">> = iolist_to_binary(cow_http_hd:parse_wt_protocol(WTProtocol)),
 	ok.
 
 %% Both WT-Available-Protocols and WT-Protocol are Structured Fields [RFC8941]. WT-Available-Protocols is a List of Tokens, and WT-Protocol is a Token. The token in the WT-Protocol response header field MUST be one of the tokens listed in WT-Available-Protocols of the request. (3.4)

test/handlers/wt_echo_h.erl

@@ -22,7 +22,7 @@ init(Req0, _) ->
 		undefined ->
 			Req0;
 		[Protocol|_] ->
-			cowboy_req:set_resp_header(<<"wt-protocol">>, Protocol, Req0)
+			cowboy_req:set_resp_header(<<"wt-protocol">>, cow_http_hd:wt_protocol(Protocol), Req0)
 	end,
 	{cowboy_webtransport, Req, #{}}.
 
@@ -97,9 +97,9 @@ webtransport_info({try_again, Event}, Streams) ->
 	webtransport_handle(Event, Streams).
 
 terminate(Reason, Req, State=#{event_pid := EventPid}) ->
-	?LOG("WT terminate ~p ~p ~p", [Reason, Req, State]),
+	?LOG("WT terminate ~0p~n~0p~n~0p", [Reason, Req, State]),
 	EventPid ! {'$wt_echo_h', terminate, Reason, Req, State},
 	ok;
 terminate(Reason, Req, State) ->
-	?LOG("WT terminate ~p ~p ~p", [Reason, Req, State]),
+	?LOG("WT terminate ~0p~n~0p~n~0p", [Reason, Req, State]),
 	ok.