Initial support for raw send/recv operations

Gun can now be used to send or receive arbitrary data in the
following scenarios:

* Directly after connecting to a server (this is not terribly
  useful but it works nevertheless due to the Gun architecture)

* After connecting through one or more Socks and/or HTTP proxies.
  This allows using Gun's proxy capabilities to access servers
  located beyond firewalls.

* After performing an HTTP/1.1 Upgrade. This allows using Gun
  to implement custom protocols that require upgrading from
  an HTTP/1.1 connection.

As there is still no support for HTTP/2 CONNECT for the time
being, there are no relevant streams attached to those use
cases and therefore the raw protocol currently expects users
to use 'undefined' as the StreamRef value. This is not a
final decision and will most likely produce a Dialyzer
warning at this time.

1 files changed, 55 insertions, 29 deletions

diff --git a/src/gun.erl b/src/gun.erl
index 600327b..ee3a5f6 100644
--- a/src/gun.erl
+++ b/src/gun.erl
@@ -99,6 +99,7 @@
 -export([initial_tls_handshake/3]).
 -export([tls_handshake/3]).
 -export([connected_no_input/3]).
+-export([connected_data_only/3]).
 -export([connected/3]).
 -export([closing/3]).
 -export([terminate/3]).
@@ -114,8 +115,8 @@
 	| {close, ws_close_code(), iodata()}.
 -export_type([ws_frame/0]).
 
--type protocols() :: [http | http2 | socks
-	| {http, http_opts()} | {http2, http2_opts()} | {socks, socks_opts()}].
+-type protocols() :: [http | http2 | raw | socks
+	| {http, http_opts()} | {http2, http2_opts()} | {raw, raw_opts()} | {socks, socks_opts()}].
 -export_type([protocols/0]).
 
 -type opts() :: #{
@@ -158,9 +159,12 @@
 	host := inet:hostname() | inet:ip_address(),
 	port := inet:port_number(),
 	transport := tcp | tls,
-	protocol := http | http2 | socks
+	protocol := http | http2 | raw | socks
 }.
 
+-type raw_opts() :: #{}.
+-export_type([raw_opts/0]).
+
 %% @todo When/if HTTP/2 CONNECT gets implemented, we will want an option here
 %% to indicate that the request must be sent on an existing CONNECT stream.
 %% This is of course not required for HTTP/1.1 since the CONNECT takes over
@@ -359,7 +363,7 @@ check_protocols_opt(Protocols) ->
 	%% Protocols must not appear more than once, and they
 	%% must be one of http, http2 or socks.
 	ProtoNames0 = lists:usort([case P0 of {P, _} -> P; P -> P end || P0 <- Protocols]),
-	ProtoNames = [P || P <- ProtoNames0, lists:member(P, [http, http2, socks])],
+	ProtoNames = [P || P <- ProtoNames0, lists:member(P, [http, http2, raw, socks])],
 	case length(Protocols) =:= length(ProtoNames) of
 		false -> error;
 		true ->
@@ -368,6 +372,7 @@ check_protocols_opt(Protocols) ->
 			TupleCheck = [case P of
 				{http, Opts} -> gun_http:check_options(Opts);
 				{http2, Opts} -> gun_http2:check_options(Opts);
+				{raw, Opts} -> gun_raw:check_options(Opts);
 				{socks, Opts} -> gun_socks:check_options(Opts)
 			end || P <- Protocols, is_tuple(P)],
 			case lists:usort(TupleCheck) of
@@ -382,6 +387,7 @@ consider_tracing(ServerPid, #{trace := true}) ->
 	dbg:tpl(gun, [{'_', [], [{return_trace}]}]),
 	dbg:tpl(gun_http, [{'_', [], [{return_trace}]}]),
 	dbg:tpl(gun_http2, [{'_', [], [{return_trace}]}]),
+	dbg:tpl(gun_raw, [{'_', [], [{return_trace}]}]),
 	dbg:tpl(gun_socks, [{'_', [], [{return_trace}]}]),
 	dbg:tpl(gun_ws, [{'_', [], [{return_trace}]}]),
 	dbg:p(ServerPid, all);
@@ -688,14 +694,18 @@ await_body(ServerPid, StreamRef, Timeout, MRef, Acc) ->
 		{error, timeout}
 	end.
 
--spec await_up(pid()) -> {ok, http | http2} | {error, {down, any()} | timeout}.
+-spec await_up(pid())
+	-> {ok, http | http2 | raw | socks}
+	| {error, {down, any()} | timeout}.
 await_up(ServerPid) ->
 	MRef = monitor(process, ServerPid),
 	Res = await_up(ServerPid, 5000, MRef),
 	demonitor(MRef, [flush]),
 	Res.
 
--spec await_up(pid(), reference() | timeout()) -> {ok, http | http2} | {error, {down, any()} | timeout}.
+-spec await_up(pid(), reference() | timeout())
+	-> {ok, http | http2 | raw | socks}
+	| {error, {down, any()} | timeout}.
 await_up(ServerPid, MRef) when is_reference(MRef) ->
 	await_up(ServerPid, 5000, MRef);
 await_up(ServerPid, Timeout) ->
@@ -704,7 +714,9 @@ await_up(ServerPid, Timeout) ->
 	demonitor(MRef, [flush]),
 	Res.
 
--spec await_up(pid(), timeout(), reference()) -> {ok, http | http2} | {error, {down, any()} | timeout}.
+-spec await_up(pid(), timeout(), reference())
+	-> {ok, http | http2 | raw | socks}
+	| {error, {down, any()} | timeout}.
 await_up(ServerPid, Timeout, MRef) ->
 	receive
 		{gun_up, ServerPid, Protocol} ->
@@ -831,6 +843,7 @@ start_link(Owner, Host, Port, Opts) ->
 init({Owner, Host, Port, Opts}) ->
 	Retry = maps:get(retry, Opts, 5),
 	OriginTransport = maps:get(transport, Opts, default_transport(Port)),
+	%% @todo The OriginScheme is not http when we connect to socks/raw.
 	{OriginScheme, Transport} = case OriginTransport of
 		tcp -> {<<"http">>, gun_tcp};
 		tls -> {<<"https">>, gun_tls}
@@ -963,7 +976,7 @@ ensure_alpn_sni(Protocols0, TransOpts0, #state{origin_host=OriginHost}) ->
 	Protocols = [case P of
 		http -> <<"http/1.1">>;
 		http2 -> <<"h2">>
-	end || P <- Protocols0, is_atom(P)],
+	end || P <- Protocols0, lists:member(P, [http, http2])],
 	TransOpts = [
 		{alpn_advertised_protocols, Protocols},
 		{client_preferred_next_protocols, {client, Protocols, <<"http/1.1">>}}
@@ -1022,7 +1035,7 @@ tls_handshake(info, {gun_tls_proxy, Socket, Error = {error, Reason}, {HandshakeE
 	}, EvHandlerState0),
 	commands([Error], State#state{event_handler_state=EvHandlerState});
 tls_handshake(Type, Event, State) ->
-	handle_common_connected(Type, Event, ?FUNCTION_NAME, State).
+	handle_common_connected_no_input(Type, Event, ?FUNCTION_NAME, State).
 
 normal_tls_handshake(Socket, State=#state{event_handler=EvHandler, event_handler_state=EvHandlerState0},
 		HandshakeEvent0=#{tls_opts := TLSOpts0, timeout := TLSTimeout}, Protocols) ->
@@ -1053,6 +1066,9 @@ protocol_negotiated({error, protocol_not_negotiated}, [Protocol]) -> Protocol;
 protocol_negotiated({error, protocol_not_negotiated}, _) -> http.
 
 connected_no_input(Type, Event, State) ->
+	handle_common_connected_no_input(Type, Event, ?FUNCTION_NAME, State).
+
+connected_data_only(Type, Event, State) ->
 	handle_common_connected(Type, Event, ?FUNCTION_NAME, State).
 
 connected(internal, {connected, Socket, Protocol0},
@@ -1151,8 +1167,22 @@ closing(Type, Event, State) ->
 
 %% Common events when we have a connection.
 %%
+%% One function accepts new input, the other doesn't.
+
+%% @todo Do we want to reject ReplyTo if it's not the process
+%% who initiated the connection? For both data and cancel.
+handle_common_connected(cast, {data, ReplyTo, StreamRef, IsFin, Data}, _,
+		State=#state{protocol=Protocol, protocol_state=ProtoState,
+			event_handler=EvHandler, event_handler_state=EvHandlerState0}) ->
+	{ProtoState2, EvHandlerState} = Protocol:data(ProtoState,
+		StreamRef, ReplyTo, IsFin, Data, EvHandler, EvHandlerState0),
+	{keep_state, State#state{protocol_state=ProtoState2, event_handler_state=EvHandlerState}};
+handle_common_connected(Type, Event, StateName, StateData) ->
+	handle_common_connected_no_input(Type, Event, StateName, StateData).
+
 %% Socket events.
-handle_common_connected(info, {OK, Socket, Data}, _, State0=#state{socket=Socket, messages={OK, _, _},
+handle_common_connected_no_input(info, {OK, Socket, Data}, _,
+		State0=#state{socket=Socket, messages={OK, _, _},
 		protocol=Protocol, protocol_state=ProtoState,
 		event_handler=EvHandler, event_handler_state=EvHandlerState0}) ->
 	{Commands, EvHandlerState} = Protocol:handle(Data, ProtoState, EvHandler, EvHandlerState0),
@@ -1164,27 +1194,22 @@ handle_common_connected(info, {OK, Socket, Data}, _, State0=#state{socket=Socket
 		Res ->
 			Res
 	end;
-handle_common_connected(info, {Closed, Socket}, _, State=#state{socket=Socket, messages={_, Closed, _}}) ->
+handle_common_connected_no_input(info, {Closed, Socket}, _,
+		State=#state{socket=Socket, messages={_, Closed, _}}) ->
 	disconnect(State, closed);
-handle_common_connected(info, {Error, Socket, Reason}, _, State=#state{socket=Socket, messages={_, _, Error}}) ->
+handle_common_connected_no_input(info, {Error, Socket, Reason}, _,
+		State=#state{socket=Socket, messages={_, _, Error}}) ->
 	disconnect(State, {error, Reason});
 %% Timeouts.
 %% @todo HTTP/2 requires more timeouts than just the keepalive timeout.
 %% We should have a timeout function in protocols that deal with
 %% received timeouts. Currently the timeout messages are ignored.
-handle_common_connected(info, keepalive, _, State=#state{protocol=Protocol, protocol_state=ProtoState}) ->
+handle_common_connected_no_input(info, keepalive, _,
+		State=#state{protocol=Protocol, protocol_state=ProtoState}) ->
 	ProtoState2 = Protocol:keepalive(ProtoState),
 	{keep_state, keepalive_timeout(State#state{protocol_state=ProtoState2})};
-%% @todo Do we want to reject ReplyTo if it's not the process
-%% who initiated the connection? For both data and cancel.
-handle_common_connected(cast, {data, ReplyTo, StreamRef, IsFin, Data}, _,
-		State=#state{protocol=Protocol, protocol_state=ProtoState,
-			event_handler=EvHandler, event_handler_state=EvHandlerState0}) ->
-	{ProtoState2, EvHandlerState} = Protocol:data(ProtoState,
-		StreamRef, ReplyTo, IsFin, Data, EvHandler, EvHandlerState0),
-	{keep_state, State#state{protocol_state=ProtoState2, event_handler_state=EvHandlerState}};
-handle_common_connected(cast, {update_flow, ReplyTo, StreamRef, Flow}, _, State0=#state{
-		protocol=Protocol, protocol_state=ProtoState}) ->
+handle_common_connected_no_input(cast, {update_flow, ReplyTo, StreamRef, Flow}, _,
+		State0=#state{protocol=Protocol, protocol_state=ProtoState}) ->
 	Commands = Protocol:update_flow(ProtoState, ReplyTo, StreamRef, Flow),
 	case commands(Commands, State0) of
 		{keep_state, State} ->
@@ -1192,16 +1217,16 @@ handle_common_connected(cast, {update_flow, ReplyTo, StreamRef, Flow}, _, State0
 		Res ->
 			Res
 	end;
-handle_common_connected(cast, {cancel, ReplyTo, StreamRef}, _, State=#state{
-		protocol=Protocol, protocol_state=ProtoState,
+handle_common_connected_no_input(cast, {cancel, ReplyTo, StreamRef}, _,
+		State=#state{protocol=Protocol, protocol_state=ProtoState,
 		event_handler=EvHandler, event_handler_state=EvHandlerState0}) ->
 	{ProtoState2, EvHandlerState} = Protocol:cancel(ProtoState,
 		StreamRef, ReplyTo, EvHandler, EvHandlerState0),
 	{keep_state, State#state{protocol_state=ProtoState2, event_handler_state=EvHandlerState}};
-handle_common_connected({call, From}, {stream_info, StreamRef}, _,
+handle_common_connected_no_input({call, From}, {stream_info, StreamRef}, _,
 		#state{protocol=Protocol, protocol_state=ProtoState}) ->
 	{keep_state_and_data, {reply, From, Protocol:stream_info(ProtoState, StreamRef)}};
-handle_common_connected(Type, Event, StateName, State) ->
+handle_common_connected_no_input(Type, Event, StateName, State) ->
 	handle_common(Type, Event, StateName, State).
 
 %% Common events.
@@ -1379,8 +1404,9 @@ disconnect_flush(State=#state{socket=Socket, messages={OK, Closed, Error}}) ->
 
 protocol_handler(http) -> gun_http;
 protocol_handler(http2) -> gun_http2;
-protocol_handler(ws) -> gun_ws;
-protocol_handler(socks) -> gun_socks.
+protocol_handler(raw) -> gun_raw;
+protocol_handler(socks) -> gun_socks;
+protocol_handler(ws) -> gun_ws.
 
 active(State=#state{active=false}) ->
 	State;