%% Copyright (c) 2011-2014, Loïc Hoguin <[email protected]>
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
%% Cowboy supports versions 7 through 17 of the Websocket drafts.
%% It also supports RFC6455, the proposed standard for Websocket.
-module(cowboy_websocket).
-behaviour(cowboy_sub_protocol).
%% Ignore the deprecation warning for crypto:sha/1.
%% @todo Remove when we support only R16B+.
-compile(nowarn_deprecated_function).
-export([upgrade/4]).
-export([handler_loop/4]).
-type close_code() :: 1000..4999.
-export_type([close_code/0]).
-type frame() :: close | ping | pong
| {text | binary | close | ping | pong, iodata()}
| {close, close_code(), iodata()}.
-export_type([frame/0]).
-type opcode() :: 0 | 1 | 2 | 8 | 9 | 10.
-type mask_key() :: 0..16#ffffffff.
-type frag_state() :: undefined
| {nofin, opcode(), binary()} | {fin, opcode(), binary()}.
-type rsv() :: << _:3 >>.
-type terminate_reason() :: {normal | error | remote, atom()}
| {remote, close_code(), binary()}.
-record(state, {
env :: cowboy_middleware:env(),
socket = undefined :: inet:socket(),
transport = undefined :: module(),
handler :: module(),
key = undefined :: undefined | binary(),
timeout = infinity :: timeout(),
timeout_ref = undefined :: undefined | reference(),
messages = undefined :: undefined | {atom(), atom(), atom()},
hibernate = false :: boolean(),
frag_state = undefined :: frag_state(),
utf8_state = <<>> :: binary(),
deflate_frame = false :: boolean(),
inflate_state :: undefined | port(),
deflate_state :: undefined | port()
}).
-spec upgrade(Req, Env, module(), any())
-> {ok, Req, Env}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req(), Env::cowboy_middleware:env().
upgrade(Req, Env, Handler, HandlerOpts) ->
{_, Ref} = lists:keyfind(listener, 1, Env),
ranch:remove_connection(Ref),
[Socket, Transport] = cowboy_req:get([socket, transport], Req),
State = #state{env=Env, socket=Socket, transport=Transport,
handler=Handler},
try websocket_upgrade(State, Req) of
{ok, State2, Req2} ->
handler_init(State2, Req2, HandlerOpts)
catch _:_ ->
cowboy_req:maybe_reply(400, Req),
exit(normal)
end.
-spec websocket_upgrade(#state{}, Req)
-> {ok, #state{}, Req} when Req::cowboy_req:req().
websocket_upgrade(State, Req) ->
{ok, ConnTokens, Req2}
= cowboy_req:parse_header(<<"connection">>, Req),
true = lists:member(<<"upgrade">>, ConnTokens),
%% @todo Should probably send a 426 if the Upgrade header is missing.
{ok, [<<"websocket">>], Req3}
= cowboy_req:parse_header(<<"upgrade">>, Req2),
{Version, Req4} = cowboy_req:header(<<"sec-websocket-version">>, Req3),
IntVersion = list_to_integer(binary_to_list(Version)),
true = (IntVersion =:= 7) orelse (IntVersion =:= 8)
orelse (IntVersion =:= 13),
{Key, Req5} = cowboy_req:header(<<"sec-websocket-key">>, Req4),
false = Key =:= undefined,
websocket_extensions(State#state{key=Key},
cowboy_req:set_meta(websocket_version, IntVersion, Req5)).
-spec websocket_extensions(#state{}, Req)
-> {ok, #state{}, Req} when Req::cowboy_req:req().
websocket_extensions(State, Req) ->
case cowboy_req:parse_header(<<"sec-websocket-extensions">>, Req) of
{ok, Extensions, Req2} when Extensions =/= undefined ->
[Compress] = cowboy_req:get([resp_compress], Req),
case lists:keyfind(<<"x-webkit-deflate-frame">>, 1, Extensions) of
{<<"x-webkit-deflate-frame">>, []} when Compress =:= true ->
Inflate = zlib:open(),
Deflate = zlib:open(),
% Since we are negotiating an unconstrained deflate-frame
% then we must be willing to accept frames using the
% maximum window size which is 2^15. The negative value
% indicates that zlib headers are not used.
ok = zlib:inflateInit(Inflate, -15),
% Initialize the deflater with a window size of 2^15 bits and disable
% the zlib headers.
ok = zlib:deflateInit(Deflate, best_compression, deflated, -15, 8, default),
{ok, State#state{
deflate_frame = true,
inflate_state = Inflate,
deflate_state = Deflate
}, cowboy_req:set_meta(websocket_compress, true, Req2)};
_ ->
{ok, State, cowboy_req:set_meta(websocket_compress, false, Req2)}
end;
_ ->
{ok, State, cowboy_req:set_meta(websocket_compress, false, Req)}
end.
-spec handler_init(#state{}, Req, any())
-> {ok, Req, cowboy_middleware:env()} | {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
handler_init(State=#state{env=Env, transport=Transport,
handler=Handler}, Req, HandlerOpts) ->
try Handler:websocket_init(Transport:name(), Req, HandlerOpts) of
{ok, Req2, HandlerState} ->
websocket_handshake(State, Req2, HandlerState);
{ok, Req2, HandlerState, hibernate} ->
websocket_handshake(State#state{hibernate=true},
Req2, HandlerState);
{ok, Req2, HandlerState, Timeout} ->
websocket_handshake(State#state{timeout=Timeout},
Req2, HandlerState);
{ok, Req2, HandlerState, Timeout, hibernate} ->
websocket_handshake(State#state{timeout=Timeout,
hibernate=true}, Req2, HandlerState);
{shutdown, Req2} ->
cowboy_req:ensure_response(Req2, 400),
{ok, Req2, [{result, closed}|Env]}
catch Class:Reason ->
cowboy_req:maybe_reply(400, Req),
erlang:Class([
{reason, Reason},
{mfa, {Handler, websocket_init, 3}},
{stacktrace, erlang:get_stacktrace()},
{req, cowboy_req:to_list(Req)},
{opts, HandlerOpts}
])
end.
-spec websocket_handshake(#state{}, Req, any())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
websocket_handshake(State=#state{
transport=Transport, key=Key, deflate_frame=DeflateFrame},
Req, HandlerState) ->
%% @todo Change into crypto:hash/2 for R17B+ or when supporting only R16B+.
Challenge = base64:encode(crypto:sha(
<< Key/binary, "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" >>)),
Extensions = case DeflateFrame of
false -> [];
true -> [{<<"sec-websocket-extensions">>, <<"x-webkit-deflate-frame">>}]
end,
{ok, Req2} = cowboy_req:upgrade_reply(
101,
[{<<"upgrade">>, <<"websocket">>},
{<<"sec-websocket-accept">>, Challenge}|
Extensions],
Req),
%% Flush the resp_sent message before moving on.
receive {cowboy_req, resp_sent} -> ok after 0 -> ok end,
State2 = handler_loop_timeout(State),
handler_before_loop(State2#state{key=undefined,
messages=Transport:messages()}, Req2, HandlerState, <<>>).
-spec handler_before_loop(#state{}, Req, any(), binary())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
handler_before_loop(State=#state{
socket=Socket, transport=Transport, hibernate=true},
Req, HandlerState, SoFar) ->
Transport:setopts(Socket, [{active, once}]),
{suspend, ?MODULE, handler_loop,
[State#state{hibernate=false}, Req, HandlerState, SoFar]};
handler_before_loop(State=#state{socket=Socket, transport=Transport},
Req, HandlerState, SoFar) ->
Transport:setopts(Socket, [{active, once}]),
handler_loop(State, Req, HandlerState, SoFar).
-spec handler_loop_timeout(#state{}) -> #state{}.
handler_loop_timeout(State=#state{timeout=infinity}) ->
State#state{timeout_ref=undefined};
handler_loop_timeout(State=#state{timeout=Timeout, timeout_ref=PrevRef}) ->
_ = case PrevRef of undefined -> ignore; PrevRef ->
erlang:cancel_timer(PrevRef) end,
TRef = erlang:start_timer(Timeout, self(), ?MODULE),
State#state{timeout_ref=TRef}.
-spec handler_loop(#state{}, Req, any(), binary())
-> {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) ->
receive
{OK, Socket, Data} ->
State2 = handler_loop_timeout(State),
websocket_data(State2, Req, HandlerState,
<< SoFar/binary, Data/binary >>);
{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) ->
handler_loop(State, Req, HandlerState, SoFar);
Message ->
handler_call(State, Req, HandlerState,
SoFar, websocket_info, Message, fun handler_before_loop/4)
end.
%% All frames passing through this function are considered valid,
%% with the only exception of text and close frames with a payload
%% which may still contain errors.
-spec websocket_data(#state{}, Req, any(), binary())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
%% 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, State#state.deflate_frame =:= false ->
websocket_close(State, Req, HandlerState, {error, badframe});
%% Invalid opcode. Note that these opcodes may be used by extensions.
websocket_data(State, Req, HandlerState, << _:4, Opcode:4, _/bits >>)
when Opcode > 2, Opcode =/= 8, Opcode =/= 9, Opcode =/= 10 ->
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 frame MUST NOT use the zero opcode unless fragmentation was initiated.
websocket_data(State=#state{frag_state=undefined}, Req, HandlerState,
<< _:4, 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});
%% Close control frame length MUST be 0 or >= 2.
websocket_data(State, Req, HandlerState, << _:4, 8:4, _:1, 1:7, _/bits >>) ->
websocket_close(State, Req, HandlerState, {error, badframe});
%% Close control frame with incomplete close code. Need more data.
websocket_data(State, Req, HandlerState,
Data = << _:4, 8:4, 1:1, Len:7, _/bits >>)
when Len > 1, byte_size(Data) < 8 ->
handler_before_loop(State, Req, HandlerState, Data);
%% 7 bits payload length.
websocket_data(State, Req, HandlerState, << Fin:1, Rsv:3/bits, Opcode:4, 1:1,
Len:7, MaskKey:32, Rest/bits >>)
when Len < 126 ->
websocket_data(State, Req, HandlerState,
Opcode, Len, MaskKey, Rest, Rsv, Fin);
%% 16 bits payload length.
websocket_data(State, Req, HandlerState, << Fin:1, Rsv:3/bits, Opcode:4, 1:1,
126:7, Len:16, MaskKey:32, Rest/bits >>)
when Len > 125, Opcode < 8 ->
websocket_data(State, Req, HandlerState,
Opcode, Len, MaskKey, Rest, Rsv, Fin);
%% 63 bits payload length.
websocket_data(State, Req, HandlerState, << Fin:1, Rsv:3/bits, 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,
Opcode, Len, MaskKey, Rest, Rsv, 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, _:7, _/binary >>) ->
websocket_close(State, Req, HandlerState, {error, badframe});
%% 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});
%% 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});
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).
%% Initialize or update fragmentation state.
-spec websocket_data(#state{}, Req, any(),
opcode(), non_neg_integer(), mask_key(), binary(), rsv(), 0 | 1)
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
%% The opcode is only included in the first frame fragment.
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, <<>>, 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, <<>>, 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, <<>>, 0, Data, Rsv);
%% Unfragmented frame.
websocket_data(State, Req, HandlerState, Opcode, Len, MaskKey, Data, Rsv, 1) ->
websocket_payload(State, Req, HandlerState,
Opcode, Len, MaskKey, <<>>, 0, Data, Rsv).
-spec websocket_payload(#state{}, Req, any(),
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, <<>>, 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, 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, UnmaskedLen,
Data, Rsv)
when (byte_size(Data) < Len) andalso ((Opcode =:= 1) orelse
((Opcode =:= 8) andalso (Unmasked =/= <<>>))) ->
Unmasked2 = websocket_unmask(Data,
rotate_mask_key(MaskKey, UnmaskedLen), <<>>),
{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, false, State),
case is_utf8(<< Incomplete/binary, Unmasked3/binary >>) of
false ->
websocket_close(State2, Req, HandlerState, {error, badencoding});
Utf8State ->
websocket_payload_loop(State2#state{utf8_state=Utf8State},
Req, HandlerState, Opcode, Len - byte_size(Data), MaskKey,
<< Unmasked/binary, Unmasked3/binary >>,
UnmaskedLen + byte_size(Data), Rsv)
end;
websocket_payload(State=#state{utf8_state=Incomplete},
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, UnmaskedLen), <<>>),
{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, true, State),
case is_utf8(<< Incomplete/binary, Unmasked3/binary >>) of
<<>> ->
websocket_dispatch(State2#state{utf8_state= <<>>},
Req, HandlerState, Rest, Opcode,
<< Unmasked/binary, Unmasked3/binary >>);
_ ->
websocket_close(State2, Req, HandlerState, {error, badencoding})
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, UnmaskedLen,
Data, Rsv)
when byte_size(Data) < Len ->
Unmasked2 = websocket_unmask(Data,
rotate_mask_key(MaskKey, UnmaskedLen), <<>>),
{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, false, State),
case is_utf8(<< Incomplete/binary, Unmasked3/binary >>) of
false ->
websocket_close(State2, Req, HandlerState, {error, badencoding});
Utf8State ->
websocket_payload_loop(State2#state{utf8_state=Utf8State},
Req, HandlerState, Opcode, Len - byte_size(Data), MaskKey,
<< 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, UnmaskedLen,
Data, Rsv) ->
<< End:Len/binary, Rest/bits >> = Data,
Unmasked2 = websocket_unmask(End,
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= <<>>},
Req, HandlerState, Rest, Opcode,
<< Unmasked/binary, Unmasked3/binary >>);
Utf8State when is_binary(Utf8State), Fin =:= nofin ->
websocket_dispatch(State2#state{utf8_state=Utf8State},
Req, HandlerState, Rest, Opcode,
<< Unmasked/binary, Unmasked3/binary >>);
_ ->
websocket_close(State, Req, HandlerState, {error, badencoding})
end;
%% Other frames have a binary payload.
websocket_payload(State, Req, HandlerState,
Opcode, Len, MaskKey, Unmasked, UnmaskedLen, Data, Rsv)
when byte_size(Data) < Len ->
Unmasked2 = websocket_unmask(Data,
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,
<< Unmasked/binary, Unmasked3/binary >>, UnmaskedLen + byte_size(Data),
Rsv);
websocket_payload(State, Req, HandlerState,
Opcode, Len, MaskKey, Unmasked, UnmaskedLen, Data, Rsv) ->
<< End:Len/binary, Rest/bits >> = Data,
Unmasked2 = websocket_unmask(End,
rotate_mask_key(MaskKey, UnmaskedLen), <<>>),
{Unmasked3, State2} = websocket_inflate_frame(Unmasked2, Rsv, true, State),
websocket_dispatch(State2, Req, HandlerState, Rest, Opcode,
<< Unmasked/binary, Unmasked3/binary >>).
-spec websocket_inflate_frame(binary(), rsv(), boolean(), #state{}) ->
{binary(), #state{}}.
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) ->
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) ->
Unmasked;
websocket_unmask(<< O:32, Rest/bits >>, MaskKey, Acc) ->
T = O bxor MaskKey,
websocket_unmask(Rest, MaskKey, << Acc/binary, T:32 >>);
websocket_unmask(<< O:24 >>, MaskKey, Acc) ->
<< MaskKey2:24, _:8 >> = << MaskKey:32 >>,
T = O bxor MaskKey2,
<< Acc/binary, T:24 >>;
websocket_unmask(<< O:16 >>, MaskKey, Acc) ->
<< MaskKey2:16, _:16 >> = << MaskKey:32 >>,
T = O bxor MaskKey2,
<< Acc/binary, T:16 >>;
websocket_unmask(<< O:8 >>, MaskKey, Acc) ->
<< MaskKey2:8, _:24 >> = << MaskKey:32 >>,
T = O bxor MaskKey2,
<< 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)).
%% Returns <<>> if the argument is valid UTF-8, false if not,
%% or the incomplete part of the argument if we need more data.
-spec is_utf8(binary()) -> false | binary().
is_utf8(Valid = <<>>) ->
Valid;
is_utf8(<< _/utf8, Rest/binary >>) ->
is_utf8(Rest);
%% 2 bytes. Codepages C0 and C1 are invalid; fail early.
is_utf8(<< 2#1100000:7, _/bits >>) ->
false;
is_utf8(Incomplete = << 2#110:3, _:5 >>) ->
Incomplete;
%% 3 bytes.
is_utf8(Incomplete = << 2#1110:4, _:4 >>) ->
Incomplete;
is_utf8(Incomplete = << 2#1110:4, _:4, 2#10:2, _:6 >>) ->
Incomplete;
%% 4 bytes. Codepage F4 may have invalid values greater than 0x10FFFF.
is_utf8(<< 2#11110100:8, 2#10:2, High:6, _/bits >>) when High >= 2#10000 ->
false;
is_utf8(Incomplete = << 2#11110:5, _:3 >>) ->
Incomplete;
is_utf8(Incomplete = << 2#11110:5, _:3, 2#10:2, _:6 >>) ->
Incomplete;
is_utf8(Incomplete = << 2#11110:5, _:3, 2#10:2, _:6, 2#10:2, _:6 >>) ->
Incomplete;
%% Invalid.
is_utf8(_) ->
false.
-spec websocket_payload_loop(#state{}, Req, any(),
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, 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, UnmaskedLen, Data, Rsv);
{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, 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, UnmaskedLen, Rsv)
end)
end.
-spec websocket_dispatch(#state{}, Req, any(), binary(), opcode(), binary())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
%% Continuation frame.
websocket_dispatch(State=#state{frag_state={nofin, Opcode, SoFar}},
Req, HandlerState, RemainingData, 0, Payload) ->
websocket_data(State#state{frag_state={nofin, Opcode,
<< 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, << SoFar/binary, Payload/binary >>);
%% Text frame.
websocket_dispatch(State, Req, HandlerState, RemainingData, 1, Payload) ->
handler_call(State, Req, HandlerState, RemainingData,
websocket_handle, {text, Payload}, fun websocket_data/4);
%% Binary frame.
websocket_dispatch(State, Req, HandlerState, RemainingData, 2, Payload) ->
handler_call(State, Req, HandlerState, RemainingData,
websocket_handle, {binary, Payload}, fun websocket_data/4);
%% Close control frame.
websocket_dispatch(State, Req, HandlerState, _RemainingData, 8, <<>>) ->
websocket_close(State, Req, HandlerState, {remote, closed});
websocket_dispatch(State, Req, HandlerState, _RemainingData, 8,
<< Code:16, Payload/bits >>) ->
websocket_close(State, Req, HandlerState, {remote, Code, Payload});
%% Ping control frame. Send a pong back and forward the ping to the handler.
websocket_dispatch(State=#state{socket=Socket, transport=Transport},
Req, HandlerState, RemainingData, 9, Payload) ->
Len = payload_length_to_binary(byte_size(Payload)),
Transport:send(Socket, << 1:1, 0:3, 10:4, 0:1, Len/bits, Payload/binary >>),
handler_call(State, Req, HandlerState, RemainingData,
websocket_handle, {ping, Payload}, fun websocket_data/4);
%% Pong control frame.
websocket_dispatch(State, Req, HandlerState, RemainingData, 10, Payload) ->
handler_call(State, Req, HandlerState, RemainingData,
websocket_handle, {pong, Payload}, fun websocket_data/4).
-spec handler_call(#state{}, Req, any(), binary(), atom(), any(), fun())
-> {ok, Req, cowboy_middleware:env()}
| {suspend, module(), atom(), [any()]}
when Req::cowboy_req:req().
handler_call(State=#state{handler=Handler}, Req, HandlerState,
RemainingData, Callback, Message, NextState) ->
try Handler:Callback(Message, Req, HandlerState) of
{ok, Req2, HandlerState2} ->
NextState(State, Req2, HandlerState2, RemainingData);
{ok, Req2, HandlerState2, hibernate} ->
NextState(State#state{hibernate=true},
Req2, HandlerState2, RemainingData);
{reply, Payload, Req2, HandlerState2}
when is_list(Payload) ->
case websocket_send_many(Payload, State) of
{ok, State2} ->
NextState(State2, Req2, HandlerState2, RemainingData);
{shutdown, State2} ->
handler_terminate(State2, Req2, HandlerState2,
{normal, shutdown});
{{error, _} = Error, State2} ->
handler_terminate(State2, Req2, HandlerState2, Error)
end;
{reply, Payload, Req2, HandlerState2, hibernate}
when is_list(Payload) ->
case websocket_send_many(Payload, State) of
{ok, State2} ->
NextState(State2#state{hibernate=true},
Req2, HandlerState2, RemainingData);
{shutdown, State2} ->
handler_terminate(State2, Req2, HandlerState2,
{normal, shutdown});
{{error, _} = Error, State2} ->
handler_terminate(State2, Req2, HandlerState2, Error)
end;
{reply, Payload, Req2, HandlerState2} ->
case websocket_send(Payload, State) of
{ok, State2} ->
NextState(State2, Req2, HandlerState2, RemainingData);
{shutdown, State2} ->
handler_terminate(State2, Req2, HandlerState2,
{normal, shutdown});
{{error, _} = Error, State2} ->
handler_terminate(State2, Req2, HandlerState2, Error)
end;
{reply, Payload, Req2, HandlerState2, hibernate} ->
case websocket_send(Payload, State) of
{ok, State2} ->
NextState(State2#state{hibernate=true},
Req2, HandlerState2, RemainingData);
{shutdown, State2} ->
handler_terminate(State2, Req2, HandlerState2,
{normal, shutdown});
{{error, _} = Error, State2} ->
handler_terminate(State2, Req2, HandlerState2, Error)
end;
{shutdown, Req2, HandlerState2} ->
websocket_close(State, Req2, HandlerState2, {normal, shutdown})
catch Class:Reason ->
_ = websocket_close(State, Req, HandlerState, {error, handler}),
erlang:Class([
{reason, Reason},
{mfa, {Handler, Callback, 3}},
{stacktrace, erlang:get_stacktrace()},
{msg, Message},
{req, cowboy_req:to_list(Req)},
{state, HandlerState}
])
end.
websocket_opcode(text) -> 1;
websocket_opcode(binary) -> 2;
websocket_opcode(close) -> 8;
websocket_opcode(ping) -> 9;
websocket_opcode(pong) -> 10.
-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};
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;
_ -> Deflated
end,
{Deflated1, << 1:1, 0:2 >>, State}.
-spec websocket_send(frame(), #state{})
-> {ok, #state{}} | {shutdown, #state{}} | {{error, atom()}, #state{}}.
websocket_send(Type, State=#state{socket=Socket, transport=Transport})
when Type =:= close ->
Opcode = websocket_opcode(Type),
case Transport:send(Socket, << 1:1, 0:3, Opcode:4, 0:8 >>) of
ok -> {shutdown, State};
Error -> {Error, State}
end;
websocket_send(Type, State=#state{socket=Socket, transport=Transport})
when Type =:= ping; Type =:= pong ->
Opcode = websocket_opcode(Type),
{Transport:send(Socket, << 1:1, 0:3, Opcode:4, 0:8 >>), State};
websocket_send({close, Payload}, State) ->
websocket_send({close, 1000, Payload}, State);
websocket_send({Type = close, StatusCode, Payload}, State=#state{
socket=Socket, transport=Transport}) ->
Opcode = websocket_opcode(Type),
Len = 2 + iolist_size(Payload),
%% Control packets must not be > 125 in length.
true = Len =< 125,
BinLen = payload_length_to_binary(Len),
Transport:send(Socket,
[<< 1:1, 0:3, Opcode:4, 0:1, BinLen/bits, StatusCode:16 >>, Payload]),
{shutdown, State};
websocket_send({Type, Payload0}, State=#state{socket=Socket, transport=Transport}) ->
Opcode = websocket_opcode(Type),
{Payload, Rsv, State2} = websocket_deflate_frame(Opcode, iolist_to_binary(Payload0), State),
Len = iolist_size(Payload),
%% Control packets must not be > 125 in length.
true = if Type =:= ping; Type =:= pong ->
Len =< 125;
true ->
true
end,
BinLen = payload_length_to_binary(Len),
{Transport:send(Socket,
[<< 1:1, Rsv/bits, Opcode:4, 0:1, BinLen/bits >>, Payload]), State2}.
-spec websocket_send_many([frame()], #state{})
-> {ok, #state{}} | {shutdown, #state{}} | {{error, atom()}, #state{}}.
websocket_send_many([], State) ->
{ok, State};
websocket_send_many([Frame|Tail], State) ->
case websocket_send(Frame, State) of
{ok, State2} -> websocket_send_many(Tail, State2);
{shutdown, State2} -> {shutdown, State2};
{Error, State2} -> {Error, State2}
end.
-spec websocket_close(#state{}, Req, any(), terminate_reason())
-> {ok, Req, cowboy_middleware:env()}
when Req::cowboy_req:req().
websocket_close(State=#state{socket=Socket, transport=Transport},
Req, HandlerState, Reason) ->
case Reason of
{normal, _} ->
Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1000:16 >>);
{error, badframe} ->
Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1002:16 >>);
{error, badencoding} ->
Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1007:16 >>);
{error, handler} ->
Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, 1011:16 >>);
{remote, closed} ->
Transport:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>);
{remote, Code, _} ->
Transport:send(Socket, << 1:1, 0:3, 8:4, 0:1, 2:7, Code:16 >>)
end,
handler_terminate(State, Req, HandlerState, Reason).
-spec handler_terminate(#state{}, Req, any(), terminate_reason())
-> {ok, Req, cowboy_middleware:env()}
when Req::cowboy_req:req().
handler_terminate(#state{env=Env, handler=Handler},
Req, HandlerState, TerminateReason) ->
try
Handler:websocket_terminate(TerminateReason, Req, HandlerState)
catch Class:Reason ->
erlang:Class([
{reason, Reason},
{mfa, {Handler, websocket_terminate, 3}},
{stacktrace, erlang:get_stacktrace()},
{req, cowboy_req:to_list(Req)},
{state, HandlerState},
{terminate_reason, TerminateReason}
])
end,
{ok, Req, [{result, closed}|Env]}.
-spec payload_length_to_binary(0..16#7fffffffffffffff)
-> << _:7 >> | << _:23 >> | << _:71 >>.
payload_length_to_binary(N) ->
case N of
N when N =< 125 -> << N:7 >>;
N when N =< 16#ffff -> << 126:7, N:16 >>;
N when N =< 16#7fffffffffffffff -> << 127:7, N:64 >>
end.
