Merge branch 'fix/websocket-inflate-unmask' of git://github.com/soundrop/cowboy

src/cowboy_websocket.erl

@@ -57,9 +57,8 @@
 	frag_state = undefined :: frag_state(),
 	utf8_state = <<>> :: binary(),
 	deflate_frame = false :: boolean(),
-	inflate_state :: any(),
-	inflate_buffer = <<>> :: binary(),
-	deflate_state :: any()
+	inflate_state :: undefined | port(),
+	deflate_state :: undefined | port()
 }).
 
 %% @doc Upgrade an HTTP request to the Websocket protocol.
@@ -121,7 +120,6 @@ websocket_extensions(State, Req) ->
 					{ok, State#state{
 						deflate_frame = true,
 						inflate_state = Inflate,
-						inflate_buffer = <<>>,
 						deflate_state = Deflate
 					}, Req2};
 				_ ->
@@ -331,45 +329,49 @@ websocket_data(State, Req, HandlerState, Data) ->
 websocket_data(State=#state{frag_state=undefined}, Req, HandlerState,
 		Opcode, Len, MaskKey, Data, Rsv, 0) ->
 	websocket_payload(State#state{frag_state={nofin, Opcode, <<>>}},
-		Req, HandlerState, 0, Len, MaskKey, <<>>, Data, Rsv);
+		Req, HandlerState, 0, Len, MaskKey, <<>>, 0, Data, Rsv);
 %% Subsequent frame fragments.
 websocket_data(State=#state{frag_state={nofin, _, _}}, Req, HandlerState,
 		0, Len, MaskKey, Data, Rsv, 0) ->
 	websocket_payload(State, Req, HandlerState,
-		0, Len, MaskKey, <<>>, Data, Rsv);
+		0, Len, MaskKey, <<>>, 0, Data, Rsv);
 %% Final frame fragment.
 websocket_data(State=#state{frag_state={nofin, Opcode, SoFar}},
 		Req, HandlerState, 0, Len, MaskKey, Data, Rsv, 1) ->
 	websocket_payload(State#state{frag_state={fin, Opcode, SoFar}},
-		Req, HandlerState, 0, Len, MaskKey, <<>>, Data, Rsv);
+		Req, HandlerState, 0, Len, MaskKey, <<>>, 0, Data, Rsv);
 %% Unfragmented frame.
 websocket_data(State, Req, HandlerState, Opcode, Len, MaskKey, Data, Rsv, 1) ->
 	websocket_payload(State, Req, HandlerState,
-		Opcode, Len, MaskKey, <<>>, Data, Rsv).
+		Opcode, Len, MaskKey, <<>>, 0, Data, Rsv).
 
 -spec websocket_payload(#state{}, Req, any(),
-	opcode(), non_neg_integer(), mask_key(), binary(), binary(), rsv())
+	opcode(), non_neg_integer(), mask_key(), binary(), non_neg_integer(),
+	binary(), rsv())
 	-> {ok, Req, cowboy_middleware:env()}
 	| {suspend, module(), atom(), [any()]}
 	when Req::cowboy_req:req().
 %% Close control frames with a payload MUST contain a valid close code.
 websocket_payload(State, Req, HandlerState,
-		Opcode=8, Len, MaskKey, <<>>, << MaskedCode:2/binary, Rest/bits >>, Rsv) ->
+		Opcode=8, Len, MaskKey, <<>>, 0,
+		<< MaskedCode:2/binary, Rest/bits >>, Rsv) ->
 	Unmasked = << Code:16 >> = websocket_unmask(MaskedCode, MaskKey, <<>>),
 	if	Code < 1000; Code =:= 1004; Code =:= 1005; Code =:= 1006;
 				(Code > 1011) and (Code < 3000); Code > 4999 ->
 			websocket_close(State, Req, HandlerState, {error, badframe});
 		true ->
 			websocket_payload(State, Req, HandlerState,
-				Opcode, Len - 2, MaskKey, Unmasked, Rest, Rsv)
+				Opcode, Len - 2, MaskKey, Unmasked, byte_size(MaskedCode),
+				Rest, Rsv)
 	end;
 %% Text frames and close control frames MUST have a payload that is valid UTF-8.
 websocket_payload(State=#state{utf8_state=Incomplete},
-		Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Data, Rsv)
+		Req, HandlerState, Opcode, Len, MaskKey, Unmasked, UnmaskedLen,
+		Data, Rsv)
 		when (byte_size(Data) < Len) andalso ((Opcode =:= 1) orelse
 			((Opcode =:= 8) andalso (Unmasked =/= <<>>))) ->
 	Unmasked2 = websocket_unmask(Data,
-		rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>),
+		rotate_mask_key(MaskKey, UnmaskedLen), <<>>),
 	{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, false, State),
 	case is_utf8(<< Incomplete/binary, Unmasked3/binary >>) of
 		false ->
@@ -377,14 +379,16 @@ websocket_payload(State=#state{utf8_state=Incomplete},
 		Utf8State ->
 			websocket_payload_loop(State2#state{utf8_state=Utf8State},
 				Req, HandlerState, Opcode, Len - byte_size(Data), MaskKey,
-				<< Unmasked/binary, Unmasked3/binary >>, Rsv)
+				<< Unmasked/binary, Unmasked3/binary >>,
+				UnmaskedLen + byte_size(Data), Rsv)
 	end;
 websocket_payload(State=#state{utf8_state=Incomplete},
-		Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Data, Rsv)
+		Req, HandlerState, Opcode, Len, MaskKey, Unmasked, UnmaskedLen,
+		Data, Rsv)
 		when Opcode =:= 1; (Opcode =:= 8) and (Unmasked =/= <<>>) ->
 	<< End:Len/binary, Rest/bits >> = Data,
 	Unmasked2 = websocket_unmask(End,
-		rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>),
+		rotate_mask_key(MaskKey, UnmaskedLen), <<>>),
 	{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, true, State),
 	case is_utf8(<< Incomplete/binary, Unmasked3/binary >>) of
 		<<>> ->
@@ -396,10 +400,11 @@ websocket_payload(State=#state{utf8_state=Incomplete},
 	end;
 %% Fragmented text frames may cut payload in the middle of UTF-8 codepoints.
 websocket_payload(State=#state{frag_state={_, 1, _}, utf8_state=Incomplete},
-		Req, HandlerState, Opcode=0, Len, MaskKey, Unmasked, Data, Rsv)
+		Req, HandlerState, Opcode=0, Len, MaskKey, Unmasked, UnmaskedLen,
+		Data, Rsv)
 		when byte_size(Data) < Len ->
 	Unmasked2 = websocket_unmask(Data,
-		rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>),
+		rotate_mask_key(MaskKey, UnmaskedLen), <<>>),
 	{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, false, State),
 	case is_utf8(<< Incomplete/binary, Unmasked3/binary >>) of
 		false ->
@@ -407,14 +412,16 @@ websocket_payload(State=#state{frag_state={_, 1, _}, utf8_state=Incomplete},
 		Utf8State ->
 			websocket_payload_loop(State2#state{utf8_state=Utf8State},
 				Req, HandlerState, Opcode, Len - byte_size(Data), MaskKey,
-				<< Unmasked/binary, Unmasked3/binary >>, Rsv)
+				<< Unmasked/binary, Unmasked3/binary >>,
+				UnmaskedLen + byte_size(Data), Rsv)
 	end;
 websocket_payload(State=#state{frag_state={Fin, 1, _}, utf8_state=Incomplete},
-		Req, HandlerState, Opcode=0, Len, MaskKey, Unmasked, Data, Rsv) ->
+		Req, HandlerState, Opcode=0, Len, MaskKey, Unmasked, UnmaskedLen,
+		Data, Rsv) ->
 	<< End:Len/binary, Rest/bits >> = Data,
 	Unmasked2 = websocket_unmask(End,
-		rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>),
-	{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, true, State),
+		rotate_mask_key(MaskKey, UnmaskedLen), <<>>),
+	{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, Fin =:= fin, State),
 	case is_utf8(<< Incomplete/binary, Unmasked3/binary >>) of
 		<<>> ->
 			websocket_dispatch(State2#state{utf8_state= <<>>},
@@ -429,20 +436,23 @@ websocket_payload(State=#state{frag_state={Fin, 1, _}, utf8_state=Incomplete},
 	end;
 %% Other frames have a binary payload.
 websocket_payload(State, Req, HandlerState,
-		Opcode, Len, MaskKey, Unmasked, Data, Rsv)
+		Opcode, Len, MaskKey, Unmasked, UnmaskedLen, Data, Rsv)
 		when byte_size(Data) < Len ->
 	Unmasked2 = websocket_unmask(Data,
-		rotate_mask_key(MaskKey, byte_size(Unmasked)), Unmasked),
+		rotate_mask_key(MaskKey, UnmaskedLen), <<>>),
 	{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, false, State),
 	websocket_payload_loop(State2, Req, HandlerState,
-		Opcode, Len - byte_size(Data), MaskKey, Unmasked3, Rsv);
+		Opcode, Len - byte_size(Data), MaskKey,
+		<< Unmasked/binary, Unmasked3/binary >>, UnmaskedLen + byte_size(Data),
+		Rsv);
 websocket_payload(State, Req, HandlerState,
-		Opcode, Len, MaskKey, Unmasked, Data, Rsv) ->
+		Opcode, Len, MaskKey, Unmasked, UnmaskedLen, Data, Rsv) ->
 	<< End:Len/binary, Rest/bits >> = Data,
 	Unmasked2 = websocket_unmask(End,
-		rotate_mask_key(MaskKey, byte_size(Unmasked)), Unmasked),
+		rotate_mask_key(MaskKey, UnmaskedLen), <<>>),
 	{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, true, State),
-	websocket_dispatch(State2, Req, HandlerState, Rest, Opcode, Unmasked3).
+	websocket_dispatch(State2, Req, HandlerState, Rest, Opcode,
+		<< Unmasked/binary, Unmasked3/binary >>).
 
 -spec websocket_inflate_frame(binary(), rsv(), boolean(), #state{}) ->
 		{binary(), #state{}}.
@@ -450,14 +460,13 @@ websocket_inflate_frame(Data, << Rsv1:1, _:2 >>, _,
 		#state{deflate_frame = DeflateFrame} = State)
 		when DeflateFrame =:= false orelse Rsv1 =:= 0 ->
 	{Data, State};
-websocket_inflate_frame(Data, << 1:1, _:2 >>, false,
-		#state{inflate_buffer = Buffer} = State) ->
-	{<<>>, State#state{inflate_buffer = << Buffer/binary, Data/binary >>}};
-websocket_inflate_frame(Data, << 1:1, _:2 >>, true,
-		#state{inflate_state = Inflate, inflate_buffer = Buffer} = State) ->
-	Deflated = << Buffer/binary, Data/binary, 0:8, 0:8, 255:8, 255:8 >>,
-	Result = zlib:inflate(Inflate, Deflated),
-	{iolist_to_binary(Result), State#state{inflate_buffer = <<>>}}.
+websocket_inflate_frame(Data, << 1:1, _:2 >>, false, State) ->
+	Result = zlib:inflate(State#state.inflate_state, Data),
+	{iolist_to_binary(Result), State};
+websocket_inflate_frame(Data, << 1:1, _:2 >>, true, State) ->
+	Result = zlib:inflate(State#state.inflate_state,
+		<< Data/binary, 0:8, 0:8, 255:8, 255:8 >>),
+	{iolist_to_binary(Result), State}.
 
 -spec websocket_unmask(B, mask_key(), B) -> B when B::binary().
 websocket_unmask(<<>>, _, Unmasked) ->
@@ -516,19 +525,20 @@ is_utf8(_) ->
 	false.
 
 -spec websocket_payload_loop(#state{}, Req, any(),
-		opcode(), non_neg_integer(), mask_key(), binary(), rsv())
+		opcode(), non_neg_integer(), mask_key(), binary(),
+		non_neg_integer(), rsv())
 	-> {ok, Req, cowboy_middleware:env()}
 	| {suspend, module(), atom(), [any()]}
 	when Req::cowboy_req:req().
 websocket_payload_loop(State=#state{socket=Socket, transport=Transport,
 		messages={OK, Closed, Error}, timeout_ref=TRef},
-		Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Rsv) ->
+		Req, HandlerState, Opcode, Len, MaskKey, Unmasked, UnmaskedLen, Rsv) ->
 	Transport:setopts(Socket, [{active, once}]),
 	receive
 		{OK, Socket, Data} ->
 			State2 = handler_loop_timeout(State),
 			websocket_payload(State2, Req, HandlerState,
-				Opcode, Len, MaskKey, Unmasked, Data, Rsv);
+				Opcode, Len, MaskKey, Unmasked, UnmaskedLen, Data, Rsv);
 		{Closed, Socket} ->
 			handler_terminate(State, Req, HandlerState, {error, closed});
 		{Error, Socket, Reason} ->
@@ -537,13 +547,13 @@ websocket_payload_loop(State=#state{socket=Socket, transport=Transport,
 			websocket_close(State, Req, HandlerState, {normal, timeout});
 		{timeout, OlderTRef, ?MODULE} when is_reference(OlderTRef) ->
 			websocket_payload_loop(State, Req, HandlerState,
-				Opcode, Len, MaskKey, Unmasked, Rsv);
+				Opcode, Len, MaskKey, Unmasked, UnmaskedLen, Rsv);
 		Message ->
 			handler_call(State, Req, HandlerState,
 				<<>>, websocket_info, Message,
 				fun (State2, Req2, HandlerState2, _) ->
 					websocket_payload_loop(State2, Req2, HandlerState2,
-						Opcode, Len, MaskKey, Unmasked, Rsv)
+						Opcode, Len, MaskKey, Unmasked, UnmaskedLen, Rsv)
 				end)
 	end.
 
@@ -665,19 +675,20 @@ websocket_opcode(close) -> 8;
 websocket_opcode(ping) -> 9;
 websocket_opcode(pong) -> 10.
 
--spec websocket_deflate_frame(opcode(), binary(), #state{}) -> {binary(), <<_:3>>, #state{}}.
+-spec websocket_deflate_frame(opcode(), binary(), #state{}) ->
+	{binary(), rsv(), #state{}}.
 websocket_deflate_frame(Opcode, Payload,
 		State=#state{deflate_frame = DeflateFrame})
 		when DeflateFrame =:= false orelse Opcode >= 8 ->
-	{Payload, <<0:3>>, State};
+	{Payload, << 0:3 >>, State};
 websocket_deflate_frame(_, Payload, State=#state{deflate_state = Deflate}) ->
 	Deflated = iolist_to_binary(zlib:deflate(Deflate, Payload, sync)),
 	DeflatedBodyLength = erlang:size(Deflated) - 4,
 	Deflated1 = case Deflated of
-		<<Body:DeflatedBodyLength/binary, 0:8, 0:8, 255:8, 255:8>> -> Body;
+		<< Body:DeflatedBodyLength/binary, 0:8, 0:8, 255:8, 255:8 >> -> Body;
 		_ -> Deflated
 	end,
-	{Deflated1, <<1:1, 0:2>>, State}.
+	{Deflated1, << 1:1, 0:2 >>, State}.
 
 -spec websocket_send(frame(), #state{})
 -> {ok, #state{}} | {shutdown, #state{}} | {{error, atom()}, #state{}}.

test/ws_SUITE.erl

@@ -31,6 +31,8 @@
 -export([ws8_single_bytes/1]).
 -export([ws13/1]).
 -export([ws_deflate/1]).
+-export([ws_deflate_chunks/1]).
+-export([ws_deflate_fragments/1]).
 -export([ws_send_close/1]).
 -export([ws_send_close_payload/1]).
 -export([ws_send_many/1]).
@@ -53,6 +55,8 @@ groups() ->
 		ws8_single_bytes,
 		ws13,
 		ws_deflate,
+		ws_deflate_chunks,
+		ws_deflate_fragments,
 		ws_send_close,
 		ws_send_close_payload,
 		ws_send_many,
@@ -315,7 +319,7 @@ ws13(Config) ->
 ws_deflate(Config) ->
 	{port, Port} = lists:keyfind(port, 1, Config),
 	{ok, Socket} = gen_tcp:connect("localhost", Port,
-		[binary, {active, false}, {packet, raw}]),
+		[binary, {active, false}, {packet, raw}, {nodelay, true}]),
 	ok = gen_tcp:send(Socket, [
 		"GET /ws_echo HTTP/1.1\r\n"
 		"Host: localhost\r\n"
@@ -338,25 +342,104 @@ ws_deflate(Config) ->
 	{"sec-websocket-extensions", "x-webkit-deflate-frame"}
 		= lists:keyfind("sec-websocket-extensions", 1, Headers),
 
-	% send uncompressed text frame containing the Hello string
-	ok = gen_tcp:send(Socket, << 16#81, 16#85, 16#37, 16#fa, 16#21, 16#3d,
-		16#7f, 16#9f, 16#4d, 16#51, 16#58 >>),
+	Mask = 16#11223344,
+	Hello = << 242, 72, 205, 201, 201, 7, 0 >>,
+	MaskedHello = websocket_mask(Hello, Mask, <<>>),
+
+	% send compressed text frame containing the Hello string
+	ok = gen_tcp:send(Socket, << 1:1, 1:1, 0:2, 1:4, 1:1, 7:7, Mask:32,
+		MaskedHello/binary >>),
 	% receive compressed text frame containing the Hello string
-	{ok, << 1:1, 1:1, 0:2, 1:4, 0:1, 7:7, 242, 72, 205, 201, 201, 7, 0 >>}
+	{ok, << 1:1, 1:1, 0:2, 1:4, 0:1, 7:7, Hello/binary >>}
 		= gen_tcp:recv(Socket, 0, 6000),
 
-	% send uncompressed text frame containing the HelloHello string
-	% as 2 separate fragments
+	ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 1:1, 0:7, 0:32 >>), %% close
+	{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
+	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
+	ok.
+
+ws_deflate_chunks(Config) ->
+	{port, Port} = lists:keyfind(port, 1, Config),
+	{ok, Socket} = gen_tcp:connect("localhost", Port,
+		[binary, {active, false}, {packet, raw}, {nodelay, true}]),
 	ok = gen_tcp:send(Socket, [
-		<< 0:1, 0:3, 1:4, 1:1, 5:7 >>,
-		<< 16#37 >>, << 16#fa >>, << 16#21 >>, << 16#3d >>, << 16#7f >>,
-		<< 16#9f >>, << 16#4d >>, << 16#51 >>, << 16#58 >>]),
+		"GET /ws_echo HTTP/1.1\r\n"
+		"Host: localhost\r\n"
+		"Connection: Upgrade\r\n"
+		"Upgrade: websocket\r\n"
+		"Sec-WebSocket-Origin: http://localhost\r\n"
+		"Sec-WebSocket-Version: 8\r\n"
+		"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
+		"Sec-WebSocket-Extensions: x-webkit-deflate-frame\r\n"
+		"\r\n"]),
+	{ok, Handshake} = gen_tcp:recv(Socket, 0, 6000),
+	{ok, {http_response, {1, 1}, 101, "Switching Protocols"}, Rest}
+		= erlang:decode_packet(http, Handshake, []),
+	[Headers, <<>>] = websocket_headers(
+		erlang:decode_packet(httph, Rest, []), []),
+	{'Connection', "Upgrade"} = lists:keyfind('Connection', 1, Headers),
+	{'Upgrade', "websocket"} = lists:keyfind('Upgrade', 1, Headers),
+	{"sec-websocket-accept", "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="}
+		= lists:keyfind("sec-websocket-accept", 1, Headers),
+	{"sec-websocket-extensions", "x-webkit-deflate-frame"}
+		= lists:keyfind("sec-websocket-extensions", 1, Headers),
+
+	Mask = 16#11223344,
+	Hello = << 242, 72, 205, 201, 201, 7, 0 >>,
+	MaskedHello = websocket_mask(Hello, Mask, <<>>),
+
+	% send compressed text frame containing the Hello string
+	ok = gen_tcp:send(Socket, << 1:1, 1:1, 0:2, 1:4, 1:1, 7:7, Mask:32,
+		(binary:part(MaskedHello, 0, 4))/binary >>),
+	ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, binary:part(MaskedHello, 4, 3)),
+
+	% receive compressed text frame containing the Hello string
+	{ok, << 1:1, 1:1, 0:2, 1:4, 0:1, 7:7, Hello/binary >>}
+		= gen_tcp:recv(Socket, 0, 6000),
+
+	ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 1:1, 0:7, 0:32 >>), %% close
+	{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
+	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
+	ok.
+
+ws_deflate_fragments(Config) ->
+	{port, Port} = lists:keyfind(port, 1, Config),
+	{ok, Socket} = gen_tcp:connect("localhost", Port,
+		[binary, {active, false}, {packet, raw}, {nodelay, true}]),
 	ok = gen_tcp:send(Socket, [
-		<< 1:1, 0:3, 0:4, 1:1, 5:7 >>,
-		<< 16#37 >>, << 16#fa >>, << 16#21 >>, << 16#3d >>, << 16#7f >>,
-		<< 16#9f >>, << 16#4d >>, << 16#51 >>, << 16#58 >>]),
-	% receive compressed text frame containing the HelloHello string
-	{ok, << 1:1, 1:1, 0:2, 1:4, 0:1, 5:7, 242, 128, 19, 0, 0 >>}
+		"GET /ws_echo HTTP/1.1\r\n"
+		"Host: localhost\r\n"
+		"Connection: Upgrade\r\n"
+		"Upgrade: websocket\r\n"
+		"Sec-WebSocket-Origin: http://localhost\r\n"
+		"Sec-WebSocket-Version: 8\r\n"
+		"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
+		"Sec-WebSocket-Extensions: x-webkit-deflate-frame\r\n"
+		"\r\n"]),
+	{ok, Handshake} = gen_tcp:recv(Socket, 0, 6000),
+	{ok, {http_response, {1, 1}, 101, "Switching Protocols"}, Rest}
+		= erlang:decode_packet(http, Handshake, []),
+	[Headers, <<>>] = websocket_headers(
+		erlang:decode_packet(httph, Rest, []), []),
+	{'Connection', "Upgrade"} = lists:keyfind('Connection', 1, Headers),
+	{'Upgrade', "websocket"} = lists:keyfind('Upgrade', 1, Headers),
+	{"sec-websocket-accept", "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="}
+		= lists:keyfind("sec-websocket-accept", 1, Headers),
+	{"sec-websocket-extensions", "x-webkit-deflate-frame"}
+		= lists:keyfind("sec-websocket-extensions", 1, Headers),
+
+	Mask = 16#11223344,
+	Hello = << 242, 72, 205, 201, 201, 7, 0 >>,
+
+	% send compressed text frame containing the Hello string
+	% as 2 separate fragments
+	ok = gen_tcp:send(Socket, << 0:1, 1:1, 0:2, 1:4, 1:1, 4:7, Mask:32,
+		(websocket_mask(binary:part(Hello, 0, 4), Mask, <<>>))/binary >>),
+	ok = gen_tcp:send(Socket, << 1:1, 1:1, 0:2, 0:4, 1:1, 3:7, Mask:32,
+		(websocket_mask(binary:part(Hello, 4, 3), Mask, <<>>))/binary >>),
+	% receive compressed text frame containing the Hello string
+	{ok, << 1:1, 1:1, 0:2, 1:4, 0:1, 7:7, Hello/binary >>}
 		= gen_tcp:recv(Socket, 0, 6000),
 
 	ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 1:1, 0:7, 0:32 >>), %% close
@@ -632,3 +715,21 @@ websocket_headers({ok, {http_header, _I, Key, _R, Value}, Rest}, Acc) ->
 	F = fun(S) when is_atom(S) -> S; (S) -> string:to_lower(S) end,
 	websocket_headers(erlang:decode_packet(httph, Rest, []),
 		[{F(Key), Value}|Acc]).
+
+websocket_mask(<<>>, _, Unmasked) ->
+	Unmasked;
+websocket_mask(<< O:32, Rest/bits >>, MaskKey, Acc) ->
+	T = O bxor MaskKey,
+	websocket_mask(Rest, MaskKey, << Acc/binary, T:32 >>);
+websocket_mask(<< O:24 >>, MaskKey, Acc) ->
+	<< MaskKey2:24, _:8 >> = << MaskKey:32 >>,
+	T = O bxor MaskKey2,
+	<< Acc/binary, T:24 >>;
+websocket_mask(<< O:16 >>, MaskKey, Acc) ->
+	<< MaskKey2:16, _:16 >> = << MaskKey:32 >>,
+	T = O bxor MaskKey2,
+	<< Acc/binary, T:16 >>;
+websocket_mask(<< O:8 >>, MaskKey, Acc) ->
+	<< MaskKey2:8, _:24 >> = << MaskKey:32 >>,
+	T = O bxor MaskKey2,
+	<< Acc/binary, T:8 >>.