diff options
Diffstat (limited to 'src/cowboy_websocket.erl')
| -rw-r--r-- | src/cowboy_websocket.erl | 306 |
1 files changed, 147 insertions, 159 deletions
diff --git a/src/cowboy_websocket.erl b/src/cowboy_websocket.erl index ece953c..50d1c88 100644 --- a/src/cowboy_websocket.erl +++ b/src/cowboy_websocket.erl @@ -31,14 +31,8 @@ -type opcode() :: 0 | 1 | 2 | 8 | 9 | 10. -type mask_key() :: 0..16#ffffffff. - -%% The websocket_data/4 function may be called multiple times for a message. -%% The websocket_dispatch/4 function is only called once for each message. --type frag_state() :: - undefined | %% no fragmentation has been seen. - {nofin, opcode()} | %% first fragment has been seen. - {nofin, opcode(), binary()} | %% first fragment has been unmasked. - {fin, opcode(), binary()}. %% last fragment has been seen. +-type frag_state() :: undefined + | {nofin, opcode(), binary()} | {fin, opcode(), binary()}. -record(state, { env :: cowboy_middleware:env(), @@ -181,9 +175,8 @@ handler_loop_timeout(State=#state{timeout=Timeout, timeout_ref=PrevRef}) -> -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). -handler_loop(State=#state{ - socket=Socket, messages={OK, Closed, Error}, timeout_ref=TRef}, - Req, HandlerState, SoFar) -> +handler_loop(State=#state{socket=Socket, messages={OK, Closed, Error}, + timeout_ref=TRef}, Req, HandlerState, SoFar) -> receive {OK, Socket, Data} -> State2 = handler_loop_timeout(State), @@ -202,187 +195,182 @@ handler_loop(State=#state{ SoFar, websocket_info, Message, fun handler_before_loop/4) end. +%% All frames passing through this function are considered valid. -spec websocket_data(#state{}, Req, any(), binary()) -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). -%% No more data. -websocket_data(State, Req, HandlerState, <<>>) -> - handler_before_loop(State, Req, HandlerState, <<>>); -%% Incomplete. -websocket_data(State, Req, HandlerState, Data) when byte_size(Data) =:= 1 -> - handler_before_loop(State, Req, HandlerState, Data); -%% 7 bit payload length prefix exists -websocket_data(State, Req, HandlerState, - << Fin:1, Rsv:3, Opcode:4, 1:1, PayloadLen:7, Rest/bits >> - = Data) when PayloadLen < 126 -> +%% RSV bits MUST be 0 unless an extension is negotiated +%% that defines meanings for non-zero values. +websocket_data(State, Req, HandlerState, << _:1, Rsv:3, _/bits >>) + when Rsv =/= 0 -> + websocket_close(State, Req, HandlerState, {error, badframe}); +%% Control frames MUST NOT be fragmented. +websocket_data(State, Req, HandlerState, << 0:1, _:3, Opcode:4, _/bits >>) + when Opcode >= 8 -> + websocket_close(State, Req, HandlerState, {error, badframe}); +%% A fragmented message MUST start a non-zero opcode. +websocket_data(State=#state{frag_state=undefined}, Req, HandlerState, + << 0:1, _:3, 0:4, _/bits >>) -> + websocket_close(State, Req, HandlerState, {error, badframe}); +%% Non-control opcode when expecting control message or next fragment. +websocket_data(State=#state{frag_state={nofin, _, _}}, Req, HandlerState, + << _:4, Opcode:4, _/bits >>) + when Opcode =/= 0, Opcode < 8 -> + websocket_close(State, Req, HandlerState, {error, badframe}); +%% 7 bits payload length. +websocket_data(State, Req, HandlerState, << Fin:1, _Rsv:3, Opcode:4, 1:1, + Len:7, MaskKey:32, Rest/bits >>) + when Len < 126 -> websocket_data(State, Req, HandlerState, - Fin, Rsv, Opcode, PayloadLen, Rest, Data); -%% 7+16 bits payload length prefix exists -websocket_data(State, Req, HandlerState, - << Fin:1, Rsv:3, Opcode:4, 1:1, 126:7, PayloadLen:16, Rest/bits >> - = Data) when PayloadLen > 125 -> + Opcode, Len, MaskKey, Rest, Fin); +%% 16 bits payload length. +websocket_data(State, Req, HandlerState, << Fin:1, _Rsv:3, Opcode:4, 1:1, + 126:7, Len:16, MaskKey:32, Rest/bits >>) + when Len > 125, Opcode < 8 -> websocket_data(State, Req, HandlerState, - Fin, Rsv, Opcode, PayloadLen, Rest, Data); -%% 7+16 bits payload length prefix missing -websocket_data(State, Req, HandlerState, - << _Fin:1, _Rsv:3, _Opcode:4, 1:1, 126:7, Rest/bits >> - = Data) when byte_size(Rest) < 2 -> - handler_before_loop(State, Req, HandlerState, Data); -%% 7+64 bits payload length prefix exists -websocket_data(State, Req, HandlerState, - << Fin:1, Rsv:3, Opcode:4, 1:1, 127:7, 0:1, PayloadLen:63, - Rest/bits >> = Data) when PayloadLen > 16#FFFF -> + Opcode, Len, MaskKey, Rest, Fin); +%% 63 bits payload length. +websocket_data(State, Req, HandlerState, << Fin:1, _Rsv:3, Opcode:4, 1:1, + 127:7, 0:1, Len:63, MaskKey:32, Rest/bits >>) + when Len > 16#ffff, Opcode < 8 -> websocket_data(State, Req, HandlerState, - Fin, Rsv, Opcode, PayloadLen, Rest, Data); -%% 7+64 bits payload length prefix missing -websocket_data(State, Req, HandlerState, - << _Fin:1, _Rsv:3, _Opcode:4, 1:1, 127:7, Rest/bits >> - = Data) when byte_size(Rest) < 8 -> - handler_before_loop(State, Req, HandlerState, Data); -%% Invalid payload length or mask bit was not set. -websocket_data(State, Req, HandlerState, _Data) -> - websocket_close(State, Req, HandlerState, {error, badframe}). - --spec websocket_data(#state{}, Req, any(), non_neg_integer(), - non_neg_integer(), non_neg_integer(), - non_neg_integer(), binary(), binary()) - -> {ok, Req, cowboy_middleware:env()} - when Req::cowboy_req:req(). -%% A fragmented message MUST start a non-zero opcode. -websocket_data(State=#state{frag_state=undefined}, Req, HandlerState, - _Fin=0, _Rsv=0, _Opcode=0, _PayloadLen, _Rest, _Buffer) -> + Opcode, Len, MaskKey, Rest, Fin); +%% When payload length is over 63 bits, the most significant bit MUST be 0. +websocket_data(State, Req, HandlerState, << _:8, 1:1, 127:7, 1:1, _/bits >>) -> websocket_close(State, Req, HandlerState, {error, badframe}); -%% A control message MUST NOT be fragmented. -websocket_data(State, Req, HandlerState, _Fin=0, _Rsv=0, Opcode, - _PayloadLen, _Rest, _Buffer) when Opcode >= 8 -> +%% All frames sent from the client to the server are masked. +websocket_data(State, Req, HandlerState, << _:8, 0:1, _/bits >>) -> websocket_close(State, Req, HandlerState, {error, badframe}); -%% The opcode is only included in the first message fragment. -websocket_data(State=#state{frag_state=undefined}, Req, HandlerState, - _Fin=0, _Rsv=0, Opcode, PayloadLen, Rest, Data) -> - websocket_before_unmask( - State#state{frag_state={nofin, Opcode}}, Req, HandlerState, - Data, Rest, 0, PayloadLen); -%% non-control opcode when expecting control message or next fragment. -websocket_data(State=#state{frag_state={nofin, _, _}}, Req, HandlerState, _Fin, - _Rsv=0, Opcode, _Ln, _Rest, _Data) when Opcode > 0, Opcode < 8 -> +%% For the next two clauses, it can be one of the following: +%% +%% * The minimal number of bytes MUST be used to encode the length +%% * All control frames MUST have a payload length of 125 bytes or less +websocket_data(State, Req, HandlerState, << _:9, 126:7, _:48, _/bits >>) -> websocket_close(State, Req, HandlerState, {error, badframe}); -%% If the first message fragment was incomplete, retry unmasking. -websocket_data(State=#state{frag_state={nofin, Opcode}}, Req, HandlerState, - _Fin=0, _Rsv=0, Opcode, PayloadLen, Rest, Data) -> - websocket_before_unmask( - State#state{frag_state={nofin, Opcode}}, Req, HandlerState, - Data, Rest, 0, PayloadLen); -%% if the opcode is zero and the fin flag is zero, unmask and await next. -websocket_data(State=#state{frag_state={nofin, _Opcode, _Payloads}}, Req, - HandlerState, _Fin=0, _Rsv=0, _Opcode2=0, PayloadLen, Rest, - Data) -> - websocket_before_unmask( - State, Req, HandlerState, Data, Rest, 0, PayloadLen); -%% when the last fragment is seen. Update the fragmentation status. -websocket_data(State=#state{frag_state={nofin, Opcode, Payloads}}, Req, - HandlerState, _Fin=1, _Rsv=0, _Opcode=0, PayloadLen, Rest, - Data) -> - websocket_before_unmask( - State#state{frag_state={fin, Opcode, Payloads}}, - Req, HandlerState, Data, Rest, 0, PayloadLen); -%% control messages MUST NOT use 7+16 bits or 7+64 bits payload length prefixes -websocket_data(State, Req, HandlerState, _Fin, _Rsv, Opcode, PayloadLen, - _Rest, _Data) when Opcode >= 8, PayloadLen > 125 -> - websocket_close(State, Req, HandlerState, {error, badframe}); -%% unfragmented message. unmask and dispatch the message. -websocket_data(State, Req, HandlerState, _Fin=1, _Rsv=0, - Opcode, PayloadLen, Rest, Data) -> - websocket_before_unmask( - State, Req, HandlerState, Data, Rest, Opcode, PayloadLen); -%% Something was wrong with the frame. Close the connection. -websocket_data(State, Req, HandlerState, _Fin, _Rsv, _Opcode, - _PayloadLen, _Rest, _Data) -> - websocket_close(State, Req, HandlerState, {error, badframe}). +websocket_data(State, Req, HandlerState, << _:9, 127:7, _:96, _/bits >>) -> + websocket_close(State, Req, HandlerState, {error, badframe}); +%% Need more data. +websocket_data(State, Req, HandlerState, Data) -> + handler_before_loop(State, Req, HandlerState, Data). -%% Routing depending on whether unmasking is needed. --spec websocket_before_unmask(#state{}, Req, any(), binary(), - binary(), opcode(), non_neg_integer() | undefined) +%% Initialize or update fragmentation state. +-spec websocket_data(#state{}, Req, any(), + opcode(), non_neg_integer(), mask_key(), binary(), 0 | 1) -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). -websocket_before_unmask(State, Req, HandlerState, Data, - Rest, Opcode, PayloadLen) -> - case PayloadLen of - N when N + 4 > byte_size(Rest); N =:= undefined -> - %% @todo We probably should allow limiting frame length. - handler_before_loop(State, Req, HandlerState, Data); - _N -> - << MaskKey:32, Payload:PayloadLen/binary, Rest2/bits >> = Rest, - websocket_unmask(State, Req, HandlerState, Rest2, - Opcode, Payload, MaskKey) - end. +%% The opcode is only included in the first frame fragment. +websocket_data(State=#state{frag_state=undefined}, Req, HandlerState, + Opcode, Len, MaskKey, Data, 0) -> + websocket_payload(State#state{frag_state={nofin, Opcode, <<>>}}, + Req, HandlerState, 0, Len, MaskKey, <<>>, Data); +%% Subsequent frame fragments. +websocket_data(State=#state{frag_state={nofin, _, _}}, Req, HandlerState, + 0, Len, MaskKey, Data, 0) -> + websocket_payload(State, Req, HandlerState, + 0, Len, MaskKey, <<>>, Data); +%% Final frame fragment. +websocket_data(State=#state{frag_state={nofin, Opcode, SoFar}}, + Req, HandlerState, 0, Len, MaskKey, Data, 1) -> + websocket_payload(State#state{frag_state={fin, Opcode, SoFar}}, + Req, HandlerState, 0, Len, MaskKey, <<>>, Data); +%% Unfragmented frame. +websocket_data(State, Req, HandlerState, Opcode, Len, MaskKey, Data, 1) -> + websocket_payload(State, Req, HandlerState, + Opcode, Len, MaskKey, <<>>, Data). -%% Unmasking. --spec websocket_unmask(#state{}, Req, any(), binary(), - opcode(), binary(), mask_key()) +-spec websocket_payload(#state{}, Req, any(), + opcode(), non_neg_integer(), mask_key(), binary(), binary()) -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). -websocket_unmask(State, Req, HandlerState, RemainingData, - Opcode, Payload, MaskKey) -> - websocket_unmask(State, Req, HandlerState, RemainingData, - Opcode, Payload, MaskKey, <<>>). +websocket_payload(State, Req, HandlerState, + Opcode, Len, MaskKey, Unmasked, Data) + when byte_size(Data) < Len -> + Unmasked2 = websocket_unmask(Data, + rotate_mask_key(MaskKey, byte_size(Unmasked)), Unmasked), + websocket_payload_loop(State, Req, HandlerState, + Opcode, Len - byte_size(Data), MaskKey, Unmasked2); +websocket_payload(State, Req, HandlerState, + Opcode, Len, MaskKey, Unmasked, Data) -> + << End:Len/binary, Rest/bits >> = Data, + Unmasked2 = websocket_unmask(End, + rotate_mask_key(MaskKey, byte_size(Unmasked)), Unmasked), + websocket_dispatch(State, Req, HandlerState, Rest, Opcode, Unmasked2). --spec websocket_unmask(#state{}, Req, any(), binary(), - opcode(), binary(), mask_key(), binary()) - -> {ok, Req, cowboy_middleware:env()} - | {suspend, module(), atom(), [any()]} - when Req::cowboy_req:req(). -websocket_unmask(State, Req, HandlerState, RemainingData, - Opcode, << O:32, Rest/bits >>, MaskKey, Acc) -> +-spec websocket_unmask(B, mask_key(), B) -> B when B::binary(). +websocket_unmask(<<>>, _, Unmasked) -> + Unmasked; +websocket_unmask(<< O:32, Rest/bits >>, MaskKey, Acc) -> T = O bxor MaskKey, - websocket_unmask(State, Req, HandlerState, RemainingData, - Opcode, Rest, MaskKey, << Acc/binary, T:32 >>); -websocket_unmask(State, Req, HandlerState, RemainingData, - Opcode, << O:24 >>, MaskKey, Acc) -> + websocket_unmask(Rest, MaskKey, << Acc/binary, T:32 >>); +websocket_unmask(<< O:24 >>, MaskKey, Acc) -> << MaskKey2:24, _:8 >> = << MaskKey:32 >>, T = O bxor MaskKey2, - websocket_dispatch(State, Req, HandlerState, RemainingData, - Opcode, << Acc/binary, T:24 >>); -websocket_unmask(State, Req, HandlerState, RemainingData, - Opcode, << O:16 >>, MaskKey, Acc) -> + << Acc/binary, T:24 >>; +websocket_unmask(<< O:16 >>, MaskKey, Acc) -> << MaskKey2:16, _:16 >> = << MaskKey:32 >>, T = O bxor MaskKey2, - websocket_dispatch(State, Req, HandlerState, RemainingData, - Opcode, << Acc/binary, T:16 >>); -websocket_unmask(State, Req, HandlerState, RemainingData, - Opcode, << O:8 >>, MaskKey, Acc) -> + << Acc/binary, T:16 >>; +websocket_unmask(<< O:8 >>, MaskKey, Acc) -> << MaskKey2:8, _:24 >> = << MaskKey:32 >>, T = O bxor MaskKey2, - websocket_dispatch(State, Req, HandlerState, RemainingData, - Opcode, << Acc/binary, T:8 >>); -websocket_unmask(State, Req, HandlerState, RemainingData, - Opcode, <<>>, _MaskKey, Acc) -> - websocket_dispatch(State, Req, HandlerState, RemainingData, - Opcode, Acc). + << Acc/binary, T:8 >>. + +%% Because we unmask on the fly we need to continue from the right mask byte. +-spec rotate_mask_key(mask_key(), non_neg_integer()) -> mask_key(). +rotate_mask_key(MaskKey, UnmaskedLen) -> + Left = UnmaskedLen rem 4, + Right = 4 - Left, + (MaskKey bsl (Left * 8)) + (MaskKey bsr (Right * 8)). + +-spec websocket_payload_loop(#state{}, Req, any(), + opcode(), non_neg_integer(), mask_key(), binary()) + -> {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) -> + Transport:setopts(Socket, [{active, once}]), + receive + {OK, Socket, Data} -> + State2 = handler_loop_timeout(State), + websocket_payload(State2, Req, HandlerState, + Opcode, Len, MaskKey, Unmasked, Data); + {Closed, Socket} -> + handler_terminate(State, Req, HandlerState, {error, closed}); + {Error, Socket, Reason} -> + handler_terminate(State, Req, HandlerState, {error, Reason}); + {timeout, TRef, ?MODULE} -> + websocket_close(State, Req, HandlerState, {normal, timeout}); + {timeout, OlderTRef, ?MODULE} when is_reference(OlderTRef) -> + websocket_payload_loop(State, Req, HandlerState, + Opcode, Len, MaskKey, Unmasked); + Message -> + handler_call(State, Req, HandlerState, + <<>>, websocket_info, Message, + fun (State2, Req2, HandlerState2, _) -> + websocket_payload_loop(State2, Req2, HandlerState2, + Opcode, Len, MaskKey, Unmasked) + end) + end. -%% Dispatching. -spec websocket_dispatch(#state{}, Req, any(), binary(), opcode(), binary()) -> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]} when Req::cowboy_req:req(). -%% First frame of a fragmented message unmasked. Expect intermediate or last. -websocket_dispatch(State=#state{frag_state={nofin, Opcode}}, Req, HandlerState, - RemainingData, 0, Payload) -> - websocket_data(State#state{frag_state={nofin, Opcode, Payload}}, - Req, HandlerState, RemainingData); -%% Intermediate frame of a fragmented message unmasked. Add payload to buffer. -websocket_dispatch(State=#state{frag_state={nofin, Opcode, Payloads}}, Req, - HandlerState, RemainingData, 0, Payload) -> +%% Continuation frame. +websocket_dispatch(State=#state{frag_state={nofin, Opcode, SoFar}}, + Req, HandlerState, RemainingData, 0, Payload) -> websocket_data(State#state{frag_state={nofin, Opcode, - <<Payloads/binary, Payload/binary>>}}, Req, HandlerState, - RemainingData); -%% Last frame of a fragmented message unmasked. Dispatch to handler. -websocket_dispatch(State=#state{frag_state={fin, Opcode, Payloads}}, Req, - HandlerState, RemainingData, 0, Payload) -> + << SoFar/binary, Payload/binary >>}}, Req, HandlerState, RemainingData); +%% Last continuation frame. +websocket_dispatch(State=#state{frag_state={fin, Opcode, SoFar}}, + Req, HandlerState, RemainingData, 0, Payload) -> websocket_dispatch(State#state{frag_state=undefined}, Req, HandlerState, - RemainingData, Opcode, <<Payloads/binary, Payload/binary>>); + RemainingData, Opcode, << SoFar/binary, Payload/binary >>); %% Text frame. websocket_dispatch(State, Req, HandlerState, RemainingData, 1, Payload) -> handler_call(State, Req, HandlerState, RemainingData, |