diff options
Diffstat (limited to 'src/cowboy_http_websocket.erl')
| -rw-r--r-- | src/cowboy_http_websocket.erl | 138 |
1 files changed, 112 insertions, 26 deletions
diff --git a/src/cowboy_http_websocket.erl b/src/cowboy_http_websocket.erl index bc28712..ab96e93 100644 --- a/src/cowboy_http_websocket.erl +++ b/src/cowboy_http_websocket.erl @@ -46,6 +46,14 @@ -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. + -record(state, { version :: 0 | 7 | 8 | 13, handler :: module(), @@ -56,7 +64,8 @@ messages = undefined :: undefined | {atom(), atom(), atom()}, hibernate = false :: boolean(), eop :: undefined | tuple(), %% hixie-76 specific. - origin = undefined :: undefined | binary() %% hixie-76 specific. + origin = undefined :: undefined | binary(), %% hixie-76 specific. + frag_state = undefined :: frag_state() }). %% @doc Upgrade a HTTP request to the WebSocket protocol. @@ -273,31 +282,94 @@ websocket_data(State=#state{version=0, eop=EOP}, Req, HandlerState, websocket_data(State=#state{version=Version}, Req, HandlerState, Data) when Version =/= 0, byte_size(Data) =:= 1 -> handler_before_loop(State, Req, HandlerState, Data); -%% hybi data frame. -%% @todo Handle Fin. -websocket_data(State=#state{version=Version}, Req, HandlerState, Data) - when Version =/= 0 -> - << 1:1, 0:3, Opcode:4, Mask:1, PayloadLen:7, Rest/bits >> = Data, - case {PayloadLen, Rest} of - {126, _} when Opcode >= 8 -> websocket_close( - State, Req, HandlerState, {error, protocol}); - {127, _} when Opcode >= 8 -> websocket_close( - State, Req, HandlerState, {error, protocol}); - {126, << L:16, R/bits >>} -> websocket_before_unmask( - State, Req, HandlerState, Data, R, Opcode, Mask, L); - {126, Rest} -> websocket_before_unmask( - State, Req, HandlerState, Data, Rest, Opcode, Mask, undefined); - {127, << 0:1, L:63, R/bits >>} -> websocket_before_unmask( - State, Req, HandlerState, Data, R, Opcode, Mask, L); - {127, Rest} -> websocket_before_unmask( - State, Req, HandlerState, Data, Rest, Opcode, Mask, undefined); - {PayloadLen, Rest} -> websocket_before_unmask( - State, Req, HandlerState, Data, Rest, Opcode, Mask, PayloadLen) - end; -%% Something was wrong with the frame. Close the connection. -websocket_data(State, Req, HandlerState, _Bad) -> +%% 7 bit payload length prefix exists +websocket_data(State, Req, HandlerState, + << Fin:1, Rsv:3, Opcode:4, Mask:1, PayloadLen:7, Rest/bits >> + = Data) when PayloadLen < 126 -> + websocket_data(State, Req, HandlerState, + Fin, Rsv, Opcode, Mask, PayloadLen, Rest, Data); +%% 7+16 bits payload length prefix exists +websocket_data(State, Req, HandlerState, + << Fin:1, Rsv:3, Opcode:4, Mask:1, 126:7, PayloadLen:16, Rest/bits >> + = Data) when PayloadLen > 125 -> + websocket_data(State, Req, HandlerState, + Fin, Rsv, Opcode, Mask, PayloadLen, Rest, Data); +%% 7+16 bits payload length prefix missing +websocket_data(State, Req, HandlerState, + << _Fin:1, _Rsv:3, _Opcode:4, _Mask: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, Mask:1, 127:7, 0:1, PayloadLen:63, + Rest/bits >> = Data) when PayloadLen > 16#FFFF -> + websocket_data(State, Req, HandlerState, + Fin, Rsv, Opcode, Mask, PayloadLen, Rest, Data); +%% 7+64 bits payload length prefix missing +websocket_data(State, Req, HandlerState, + << _Fin:1, _Rsv:3, _Opcode:4, _Mask:1, 127:7, Rest/bits >> + = Data) when byte_size(Rest) < 8 -> + handler_before_loop(State, Req, HandlerState, Data); +%% invalid payload length prefix. +websocket_data(State, Req, HandlerState, _Data) -> websocket_close(State, Req, HandlerState, {error, badframe}). + +-spec websocket_data(#state{}, #http_req{}, any(), non_neg_integer(), + non_neg_integer(), non_neg_integer(), non_neg_integer(), + non_neg_integer(), binary(), binary()) -> closed. +%% A fragmented message MUST start a non-zero opcode. +websocket_data(State=#state{frag_state=undefined}, Req, HandlerState, + _Fin=0, _Rsv=0, _Opcode=0, _Mask, _PayloadLen, _Rest, _Buffer) -> + websocket_close(State, Req, HandlerState, {error, badframe}); +%% A control message MUST NOT be fragmented. +websocket_data(State, Req, HandlerState, _Fin=0, _Rsv=0, Opcode, _Mask, + _PayloadLen, _Rest, _Buffer) when Opcode >= 8 -> + 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, Mask, PayloadLen, Rest, Data) -> + websocket_before_unmask( + State#state{frag_state={nofin, Opcode}}, Req, HandlerState, + Data, Rest, 0, Mask, PayloadLen); +%% non-control opcode when expecting control message or next fragment. +websocket_data(State=#state{frag_state={nofin, _, _}}, Req, HandlerState, _Fin, + _Rsv=0, Opcode, _Mask, _Ln, _Rest, _Data) when Opcode > 0, Opcode < 8 -> + 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, Mask, PayloadLen, Rest, Data) -> + websocket_before_unmask( + State#state{frag_state={nofin, Opcode}}, Req, HandlerState, + Data, Rest, 0, Mask, 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, Mask, PayloadLen, Rest, + Data) -> + websocket_before_unmask( + State, Req, HandlerState, Data, Rest, 0, Mask, 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, Mask, PayloadLen, Rest, + Data) -> + websocket_before_unmask( + State#state{frag_state={fin, Opcode, Payloads}}, + Req, HandlerState, Data, Rest, 0, Mask, PayloadLen); +%% control messages MUST NOT use 7+16 bits or 7+64 bits payload length prefixes +websocket_data(State, Req, HandlerState, _Fin, _Rsv, Opcode, _Mask, PayloadLen, + _Rest, _Data) when Opcode >= 8, PayloadLen > 125 -> + websocket_close(State, Req, HandlerState, {error, protocol}); +%% unfragmented message. unmask and dispatch the message. +websocket_data(State=#state{version=Version}, Req, HandlerState, _Fin=1, _Rsv=0, + Opcode, Mask, PayloadLen, Rest, Data) when Version =/= 0 -> + websocket_before_unmask( + State, Req, HandlerState, Data, Rest, Opcode, Mask, PayloadLen); +%% Something was wrong with the frame. Close the connection. +websocket_data(State, Req, HandlerState, _Fin, _Rsv, _Opcode, _Mask, + _PayloadLen, _Rest, _Data) -> + websocket_close(State, Req, HandlerState, {error, badframe}). + + %% hybi routing depending on whether unmasking is needed. -spec websocket_before_unmask(#state{}, #http_req{}, any(), binary(), binary(), opcode(), 0 | 1, non_neg_integer() | undefined) -> closed. @@ -356,8 +428,22 @@ websocket_unmask(State, Req, HandlerState, RemainingData, %% hybi dispatching. -spec websocket_dispatch(#state{}, #http_req{}, any(), binary(), opcode(), binary()) -> closed. -%% @todo Fragmentation. -%~ websocket_dispatch(State, Req, HandlerState, RemainingData, 0, Payload) -> +%% 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) -> + 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) -> + websocket_dispatch(State#state{frag_state=undefined}, Req, HandlerState, + RemainingData, Opcode, <<Payloads/binary, Payload/binary>>); %% Text frame. websocket_dispatch(State, Req, HandlerState, RemainingData, 1, Payload) -> handler_call(State, Req, HandlerState, RemainingData, |