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https://github.com/ninenines/cowboy.git
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Improve websocket close handling
We now always send a failure reason (bad protocol, bad encoding, etc.) unless the closure was initiated by the client and it didn't send a close code. We now check that the close frames have a payload that is valid UTF-8, unless they don't have a payload at all. We now do not crash the process anymore when bad opcodes are sent, or when the opcode 0 is sent before fragmentation was initiated. Overall this makes us closer to full compliance with the RFC.
This commit is contained in:
Loïc Hoguin
parent
5dd09737d0
commit
8d69099508
2 changed files with 63 additions and 21 deletions
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@ -196,7 +196,9 @@ handler_loop(State=#state{socket=Socket, messages={OK, Closed, Error},
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SoFar, websocket_info, Message, fun handler_before_loop/4)
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end.
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%% All frames passing through this function are considered valid.
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%% All frames passing through this function are considered valid,
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%% with the only exception of text and close frames with a payload
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%% which may still contain errors.
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-spec websocket_data(#state{}, Req, any(), binary())
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-> {ok, Req, cowboy_middleware:env()}
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| {suspend, module(), atom(), [any()]}
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@ -206,19 +208,31 @@ handler_loop(State=#state{socket=Socket, messages={OK, Closed, Error},
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websocket_data(State, Req, HandlerState, << _:1, Rsv:3, _/bits >>)
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when Rsv =/= 0 ->
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websocket_close(State, Req, HandlerState, {error, badframe});
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%% Invalid opcode. Note that these opcodes may be used by extensions.
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websocket_data(State, Req, HandlerState, << _:4, Opcode:4, _/bits >>)
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when Opcode > 2, Opcode =/= 8, Opcode =/= 9, Opcode =/= 10 ->
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websocket_close(State, Req, HandlerState, {error, badframe});
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%% Control frames MUST NOT be fragmented.
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websocket_data(State, Req, HandlerState, << 0:1, _:3, Opcode:4, _/bits >>)
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when Opcode >= 8 ->
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websocket_close(State, Req, HandlerState, {error, badframe});
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%% A fragmented message MUST start a non-zero opcode.
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%% A frame MUST NOT use the zero opcode unless fragmentation was initiated.
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websocket_data(State=#state{frag_state=undefined}, Req, HandlerState,
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<< 0:1, _:3, 0:4, _/bits >>) ->
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<< _:4, 0:4, _/bits >>) ->
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websocket_close(State, Req, HandlerState, {error, badframe});
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%% Non-control opcode when expecting control message or next fragment.
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websocket_data(State=#state{frag_state={nofin, _, _}}, Req, HandlerState,
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<< _:4, Opcode:4, _/bits >>)
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when Opcode =/= 0, Opcode < 8 ->
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websocket_close(State, Req, HandlerState, {error, badframe});
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%% Close control frame length MUST be 0 or >= 2.
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websocket_data(State, Req, HandlerState, << _:4, 8:4, _:1, 1:7, _/bits >>) ->
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websocket_close(State, Req, HandlerState, {error, badframe});
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%% Close control frame with incomplete close code. Need more data.
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websocket_data(State, Req, HandlerState,
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Data = << _:4, 8:4, 1:1, Len:7, _/bits >>)
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when Len > 1, byte_size(Data) < 8 ->
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handler_before_loop(State, Req, HandlerState, Data);
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%% 7 bits payload length.
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websocket_data(State, Req, HandlerState, << Fin:1, _Rsv:3, Opcode:4, 1:1,
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Len:7, MaskKey:32, Rest/bits >>)
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@ -286,22 +300,35 @@ websocket_data(State, Req, HandlerState, Opcode, Len, MaskKey, Data, 1) ->
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-> {ok, Req, cowboy_middleware:env()}
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| {suspend, module(), atom(), [any()]}
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when Req::cowboy_req:req().
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%% Text frames must have a payload that is valid UTF-8.
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%% Close control frames with a payload MUST contain a valid close code.
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websocket_payload(State, Req, HandlerState,
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Opcode=8, Len, MaskKey, <<>>, << MaskedCode:2/binary, Rest/bits >>) ->
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Unmasked = << Code:16 >> = websocket_unmask(MaskedCode, MaskKey, <<>>),
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if Code < 1000; Code =:= 1004; Code =:= 1005; Code =:= 1006;
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(Code > 1011) and (Code < 3000); Code > 4999 ->
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websocket_close(State, Req, HandlerState, {error, badframe});
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true ->
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websocket_payload(State, Req, HandlerState,
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Opcode, Len - 2, MaskKey, Unmasked, Rest)
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end;
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%% Text frames and close control frames MUST have a payload that is valid UTF-8.
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websocket_payload(State=#state{utf8_state=Incomplete},
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Req, HandlerState, Opcode=1, Len, MaskKey, Unmasked, Data)
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when byte_size(Data) < Len ->
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Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Data)
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when (byte_size(Data) < Len) andalso ((Opcode =:= 1) orelse
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((Opcode =:= 8) andalso (Unmasked =/= <<>>))) ->
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Unmasked2 = websocket_unmask(Data,
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rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>),
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case is_utf8(<< Incomplete/binary, Unmasked2/binary >>) of
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false ->
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websocket_close(State, Req, HandlerState, {error, badframe});
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websocket_close(State, Req, HandlerState, {error, badencoding});
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Utf8State ->
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websocket_payload_loop(State#state{utf8_state=Utf8State},
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Req, HandlerState, Opcode, Len - byte_size(Data), MaskKey,
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<< Unmasked/binary, Unmasked2/binary >>)
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end;
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websocket_payload(State=#state{utf8_state=Incomplete},
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Req, HandlerState, Opcode=1, Len, MaskKey, Unmasked, Data) ->
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Req, HandlerState, Opcode, Len, MaskKey, Unmasked, Data)
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when Opcode =:= 1; (Opcode =:= 8) and (Unmasked =/= <<>>) ->
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<< End:Len/binary, Rest/bits >> = Data,
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Unmasked2 = websocket_unmask(End,
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rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>),
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@ -311,7 +338,7 @@ websocket_payload(State=#state{utf8_state=Incomplete},
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Req, HandlerState, Rest, Opcode,
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<< Unmasked/binary, Unmasked2/binary >>);
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_ ->
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websocket_close(State, Req, HandlerState, {error, badframe})
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websocket_close(State, Req, HandlerState, {error, badencoding})
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end;
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%% Fragmented text frames may cut payload in the middle of UTF-8 codepoints.
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websocket_payload(State=#state{frag_state={_, 1, _}, utf8_state=Incomplete},
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@ -321,7 +348,7 @@ websocket_payload(State=#state{frag_state={_, 1, _}, utf8_state=Incomplete},
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rotate_mask_key(MaskKey, byte_size(Unmasked)), <<>>),
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case is_utf8(<< Incomplete/binary, Unmasked2/binary >>) of
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false ->
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websocket_close(State, Req, HandlerState, {error, badframe});
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websocket_close(State, Req, HandlerState, {error, badencoding});
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Utf8State ->
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websocket_payload_loop(State#state{utf8_state=Utf8State},
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Req, HandlerState, Opcode, Len - byte_size(Data), MaskKey,
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@ -342,7 +369,7 @@ websocket_payload(State=#state{frag_state={Fin, 1, _}, utf8_state=Incomplete},
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Req, HandlerState, Rest, Opcode,
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<< Unmasked/binary, Unmasked2/binary >>);
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_ ->
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websocket_close(State, Req, HandlerState, {error, badframe})
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websocket_close(State, Req, HandlerState, {error, badencoding})
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end;
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%% Other frames have a binary payload.
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websocket_payload(State, Req, HandlerState,
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@ -470,9 +497,11 @@ websocket_dispatch(State, Req, HandlerState, RemainingData, 2, Payload) ->
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handler_call(State, Req, HandlerState, RemainingData,
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websocket_handle, {binary, Payload}, fun websocket_data/4);
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%% Close control frame.
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%% @todo Handle the optional Payload.
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websocket_dispatch(State, Req, HandlerState, _RemainingData, 8, _Payload) ->
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websocket_close(State, Req, HandlerState, {normal, closed});
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websocket_dispatch(State, Req, HandlerState, _RemainingData, 8, <<>>) ->
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websocket_close(State, Req, HandlerState, {remote, closed});
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websocket_dispatch(State, Req, HandlerState, _RemainingData, 8,
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<< Code:16, Payload/bits >>) ->
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websocket_close(State, Req, HandlerState, {remote, Code, Payload});
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%% Ping control frame. Send a pong back and forward the ping to the handler.
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websocket_dispatch(State=#state{socket=Socket, transport=Transport},
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Req, HandlerState, RemainingData, 9, Payload) ->
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@ -621,7 +650,20 @@ websocket_send_many([Frame|Tail], State) ->
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when Req::cowboy_req:req().
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websocket_close(State=#state{socket=Socket, transport=Transport},
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Req, HandlerState, Reason) ->
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Transport:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>),
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case Reason of
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{normal, _} ->
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Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1000:16 >>);
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{error, badframe} ->
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Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1002:16 >>);
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{error, badencoding} ->
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Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1007:16 >>);
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{error, handler} ->
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Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1011:16 >>);
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{remote, closed} ->
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Transport:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>);
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{remote, Code, _} ->
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Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, Code:16 >>)
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end,
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handler_terminate(State, Req, HandlerState, Reason).
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-spec handler_terminate(#state{}, Req, any(), atom() | {atom(), atom()})
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@ -396,7 +396,7 @@ ws_send_many(Config) ->
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<< 1:1, 0:3, 1:4, 0:1, 3:7, "one",
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1:1, 0:3, 1:4, 0:1, 3:7, "two",
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1:1, 0:3, 1:4, 0:1, 6:7, "seven!" >> = Many,
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ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>), %% close
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ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 1:1, 0:7, 0:32 >>), %% close
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{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
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{error, closed} = gen_tcp:recv(Socket, 0, 6000),
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ok.
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@ -450,7 +450,7 @@ ws_text_fragments(Config) ->
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<< 16#9f >>, << 16#4d >>, << 16#51 >>, << 16#58 >>]),
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{ok, << 1:1, 0:3, 1:4, 0:1, 15:7, "HelloHelloHello" >>}
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= gen_tcp:recv(Socket, 0, 6000),
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ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>), %% close
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ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 1:1, 0:7, 0:32 >>), %% close
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{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
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{error, closed} = gen_tcp:recv(Socket, 0, 6000),
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ok.
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@ -477,7 +477,7 @@ ws_timeout_hibernate(Config) ->
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{'Upgrade', "websocket"} = lists:keyfind('Upgrade', 1, Headers),
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{"sec-websocket-accept", "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="}
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= lists:keyfind("sec-websocket-accept", 1, Headers),
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{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
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{ok, << 1:1, 0:3, 8:4, 0:1, 2:7, 1000:16 >>} = gen_tcp:recv(Socket, 0, 6000),
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{error, closed} = gen_tcp:recv(Socket, 0, 6000),
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ok.
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@ -504,7 +504,7 @@ ws_timeout_cancel(Config) ->
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{'Upgrade', "websocket"} = lists:keyfind('Upgrade', 1, Headers),
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{"sec-websocket-accept", "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="}
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= lists:keyfind("sec-websocket-accept", 1, Headers),
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{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
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{ok, << 1:1, 0:3, 8:4, 0:1, 2:7, 1000:16 >>} = gen_tcp:recv(Socket, 0, 6000),
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{error, closed} = gen_tcp:recv(Socket, 0, 6000),
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ok.
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@ -538,7 +538,7 @@ ws_timeout_reset(Config) ->
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= gen_tcp:recv(Socket, 0, 6000),
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ok = timer:sleep(500)
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end || _ <- [1, 2, 3, 4]],
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{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
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{ok, << 1:1, 0:3, 8:4, 0:1, 2:7, 1000:16 >>} = gen_tcp:recv(Socket, 0, 6000),
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{error, closed} = gen_tcp:recv(Socket, 0, 6000),
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ok.
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@ -566,7 +566,7 @@ ws_upgrade_with_opts(Config) ->
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= lists:keyfind("sec-websocket-accept", 1, Headers),
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{ok, Response} = gen_tcp:recv(Socket, 9, 6000),
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<< 1:1, 0:3, 1:4, 0:1, 7:7, "success" >> = Response,
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ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>), %% close
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ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 1:1, 0:7, 0:32 >>), %% close
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{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
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{error, closed} = gen_tcp:recv(Socket, 0, 6000),
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ok.
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