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-rw-r--r--src/cowboy_http_websocket.erl138
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,