%% Copyright (c) 2011-2017, Loïc Hoguin %% %% 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). -export([upgrade/4]). -export([upgrade/5]). -export([takeover/7]). -export([loop/3]). -export([system_continue/3]). -export([system_terminate/4]). -export([system_code_change/4]). -type call_result(State) :: {ok, State} | {ok, State, hibernate} | {reply, cow_ws:frame() | [cow_ws:frame()], State} | {reply, cow_ws:frame() | [cow_ws:frame()], State, hibernate} | {stop, State}. -type terminate_reason() :: normal | stop | timeout | remote | {remote, cow_ws:close_code(), binary()} | {error, badencoding | badframe | closed | atom()} | {crash, error | exit | throw, any()}. -callback init(Req, any()) -> {ok | module(), Req, any()} | {module(), Req, any(), any()} when Req::cowboy_req:req(). -callback websocket_init(State) -> call_result(State) when State::any(). -optional_callbacks([websocket_init/1]). -callback websocket_handle({text | binary | ping | pong, binary()}, State) -> call_result(State) when State::any(). -callback websocket_info(any(), State) -> call_result(State) when State::any(). -callback terminate(any(), cowboy_req:req(), any()) -> ok. -optional_callbacks([terminate/3]). -type opts() :: #{ compress => boolean(), idle_timeout => timeout(), max_frame_size => non_neg_integer() | infinity, req_filter => fun((cowboy_req:req()) -> map()) }. -export_type([opts/0]). -record(state, { parent :: undefined | pid(), ref :: ranch:ref(), socket = undefined :: inet:socket() | undefined, transport = undefined :: module(), handler :: module(), key = undefined :: undefined | binary(), timeout = infinity :: timeout(), timeout_ref = undefined :: undefined | reference(), compress = false :: boolean(), max_frame_size :: non_neg_integer() | infinity, messages = undefined :: undefined | {atom(), atom(), atom()}, hibernate = false :: boolean(), frag_state = undefined :: cow_ws:frag_state(), frag_buffer = <<>> :: binary(), utf8_state = 0 :: cow_ws:utf8_state(), extensions = #{} :: map(), req = #{} :: map() }). %% Stream process. -spec upgrade(Req, Env, module(), any()) -> {ok, Req, Env} when Req::cowboy_req:req(), Env::cowboy_middleware:env(). upgrade(Req, Env, Handler, HandlerState) -> upgrade(Req, Env, Handler, HandlerState, #{}). -spec upgrade(Req, Env, module(), any(), opts()) -> {ok, Req, Env} when Req::cowboy_req:req(), Env::cowboy_middleware:env(). %% @todo Immediately crash if a response has already been sent. %% @todo Error out if HTTP/2. upgrade(Req0, Env, Handler, HandlerState, Opts) -> Timeout = maps:get(idle_timeout, Opts, 60000), MaxFrameSize = maps:get(max_frame_size, Opts, infinity), Compress = maps:get(compress, Opts, false), FilteredReq = case maps:get(req_filter, Opts, undefined) of undefined -> maps:with([method, version, scheme, host, port, path, qs, peer], Req0); FilterFun -> FilterFun(Req0) end, State0 = #state{handler=Handler, timeout=Timeout, compress=Compress, max_frame_size=MaxFrameSize, req=FilteredReq}, try websocket_upgrade(State0, Req0) of {ok, State, Req} -> websocket_handshake(State, Req, HandlerState, Env); {error, upgrade_required} -> {ok, cowboy_req:reply(426, #{ <<"connection">> => <<"upgrade">>, <<"upgrade">> => <<"websocket">> }, Req0), Env} catch _:_ -> %% @todo Probably log something here? %% @todo Test that we can have 2 /ws 400 status code in a row on the same connection. %% @todo Does this even work? {ok, cowboy_req:reply(400, Req0), Env} end. websocket_upgrade(State, Req) -> ConnTokens = cowboy_req:parse_header(<<"connection">>, Req, []), case lists:member(<<"upgrade">>, ConnTokens) of false -> {error, upgrade_required}; true -> UpgradeTokens = cowboy_req:parse_header(<<"upgrade">>, Req, []), case lists:member(<<"websocket">>, UpgradeTokens) of false -> {error, upgrade_required}; true -> Version = cowboy_req:header(<<"sec-websocket-version">>, Req), IntVersion = binary_to_integer(Version), true = (IntVersion =:= 7) orelse (IntVersion =:= 8) orelse (IntVersion =:= 13), Key = cowboy_req:header(<<"sec-websocket-key">>, Req), false = Key =:= undefined, websocket_extensions(State#state{key=Key}, Req#{websocket_version => IntVersion}) end end. websocket_extensions(State=#state{compress=Compress}, Req) -> %% @todo We want different options for this. For example %% * compress everything auto %% * compress only text auto %% * compress only binary auto %% * compress nothing auto (but still enabled it) %% * disable compression case {Compress, cowboy_req:parse_header(<<"sec-websocket-extensions">>, Req)} of {true, Extensions} when Extensions =/= undefined -> websocket_extensions(State, Req, Extensions, []); _ -> {ok, State, Req} end. websocket_extensions(State, Req, [], []) -> {ok, State, Req}; websocket_extensions(State, Req, [], [<<", ">>|RespHeader]) -> {ok, State, cowboy_req:set_resp_header(<<"sec-websocket-extensions">>, lists:reverse(RespHeader), Req)}; websocket_extensions(State=#state{extensions=Extensions}, Req=#{pid := Pid}, [{<<"permessage-deflate">>, Params}|Tail], RespHeader) -> %% @todo Make deflate options configurable. Opts = #{level => best_compression, mem_level => 8, strategy => default}, try cow_ws:negotiate_permessage_deflate(Params, Extensions, Opts#{owner => Pid}) of {ok, RespExt, Extensions2} -> websocket_extensions(State#state{extensions=Extensions2}, Req, Tail, [<<", ">>, RespExt|RespHeader]); ignore -> websocket_extensions(State, Req, Tail, RespHeader) catch exit:{error, incompatible_zlib_version, _} -> websocket_extensions(State, Req, Tail, RespHeader) end; websocket_extensions(State=#state{extensions=Extensions}, Req=#{pid := Pid}, [{<<"x-webkit-deflate-frame">>, Params}|Tail], RespHeader) -> %% @todo Make deflate options configurable. Opts = #{level => best_compression, mem_level => 8, strategy => default}, try cow_ws:negotiate_x_webkit_deflate_frame(Params, Extensions, Opts#{owner => Pid}) of {ok, RespExt, Extensions2} -> websocket_extensions(State#state{extensions=Extensions2}, Req, Tail, [<<", ">>, RespExt|RespHeader]); ignore -> websocket_extensions(State, Req, Tail, RespHeader) catch exit:{error, incompatible_zlib_version, _} -> websocket_extensions(State, Req, Tail, RespHeader) end; websocket_extensions(State, Req, [_|Tail], RespHeader) -> websocket_extensions(State, Req, Tail, RespHeader). -spec websocket_handshake(#state{}, Req, any(), Env) -> {ok, Req, Env} when Req::cowboy_req:req(), Env::cowboy_middleware:env(). websocket_handshake(State=#state{key=Key}, Req=#{pid := Pid, streamid := StreamID}, HandlerState, Env) -> Challenge = base64:encode(crypto:hash(sha, << Key/binary, "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" >>)), %% @todo We don't want date and server headers. Headers = cowboy_req:response_headers(#{ <<"connection">> => <<"Upgrade">>, <<"upgrade">> => <<"websocket">>, <<"sec-websocket-accept">> => Challenge }, Req), Pid ! {{Pid, StreamID}, {switch_protocol, Headers, ?MODULE, {State, HandlerState}}}, {ok, Req, Env}. %% Connection process. -record(ps_header, { buffer = <<>> :: binary() }). -record(ps_payload, { type :: cow_ws:frame_type(), len :: non_neg_integer(), mask_key :: cow_ws:mask_key(), rsv :: cow_ws:rsv(), close_code = undefined :: undefined | cow_ws:close_code(), unmasked = <<>> :: binary(), unmasked_len = 0 :: non_neg_integer(), buffer = <<>> :: binary() }). -type parse_state() :: #ps_header{} | #ps_payload{}. -spec takeover(pid(), ranch:ref(), inet:socket(), module(), any(), binary(), {#state{}, any()}) -> no_return(). takeover(Parent, Ref, Socket, Transport, _Opts, Buffer, {State0=#state{handler=Handler}, HandlerState}) -> %% @todo We should have an option to disable this behavior. ranch:remove_connection(Ref), State = loop_timeout(State0#state{parent=Parent, ref=Ref, socket=Socket, transport=Transport, key=undefined, messages=Transport:messages()}), case erlang:function_exported(Handler, websocket_init, 1) of true -> handler_call(State, HandlerState, #ps_header{buffer=Buffer}, websocket_init, undefined, fun before_loop/3); false -> before_loop(State, HandlerState, #ps_header{buffer=Buffer}) end. before_loop(State=#state{socket=Socket, transport=Transport, hibernate=true}, HandlerState, ParseState) -> Transport:setopts(Socket, [{active, once}]), proc_lib:hibernate(?MODULE, loop, [State#state{hibernate=false}, HandlerState, ParseState]); before_loop(State=#state{socket=Socket, transport=Transport}, HandlerState, ParseState) -> Transport:setopts(Socket, [{active, once}]), loop(State, HandlerState, ParseState). -spec loop_timeout(#state{}) -> #state{}. loop_timeout(State=#state{timeout=infinity}) -> State#state{timeout_ref=undefined}; 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 loop(#state{}, any(), parse_state()) -> no_return(). loop(State=#state{parent=Parent, socket=Socket, messages={OK, Closed, Error}, timeout_ref=TRef}, HandlerState, ParseState) -> receive {OK, Socket, Data} -> State2 = loop_timeout(State), parse(State2, HandlerState, ParseState, Data); {Closed, Socket} -> terminate(State, HandlerState, {error, closed}); {Error, Socket, Reason} -> terminate(State, HandlerState, {error, Reason}); {timeout, TRef, ?MODULE} -> websocket_close(State, HandlerState, timeout); {timeout, OlderTRef, ?MODULE} when is_reference(OlderTRef) -> loop(State, HandlerState, ParseState); %% System messages. {'EXIT', Parent, Reason} -> %% @todo We should exit gracefully. exit(Reason); {system, From, Request} -> sys:handle_system_msg(Request, From, Parent, ?MODULE, [], {State, HandlerState, ParseState}); %% Calls from supervisor module. {'$gen_call', From, Call} -> cowboy_children:handle_supervisor_call(Call, From, [], ?MODULE), loop(State, HandlerState, ParseState); Message -> handler_call(State, HandlerState, ParseState, websocket_info, Message, fun before_loop/3) end. parse(State, HandlerState, PS=#ps_header{buffer=Buffer}, Data) -> parse_header(State, HandlerState, PS#ps_header{ buffer= <>}); parse(State, HandlerState, PS=#ps_payload{buffer=Buffer}, Data) -> parse_payload(State, HandlerState, PS#ps_payload{buffer= <<>>}, <>). parse_header(State=#state{max_frame_size=MaxFrameSize, frag_state=FragState, extensions=Extensions}, HandlerState, ParseState=#ps_header{buffer=Data}) -> case cow_ws:parse_header(Data, Extensions, FragState) of %% All frames sent from the client to the server are masked. {_, _, _, _, undefined, _} -> websocket_close(State, HandlerState, {error, badframe}); {_, _, _, Len, _, _} when Len > MaxFrameSize -> websocket_close(State, HandlerState, {error, badsize}); {Type, FragState2, Rsv, Len, MaskKey, Rest} -> parse_payload(State#state{frag_state=FragState2}, HandlerState, #ps_payload{type=Type, len=Len, mask_key=MaskKey, rsv=Rsv}, Rest); more -> before_loop(State, HandlerState, ParseState); error -> websocket_close(State, HandlerState, {error, badframe}) end. parse_payload(State=#state{frag_state=FragState, utf8_state=Incomplete, extensions=Extensions}, HandlerState, ParseState=#ps_payload{ type=Type, len=Len, mask_key=MaskKey, rsv=Rsv, unmasked=Unmasked, unmasked_len=UnmaskedLen}, Data) -> case cow_ws:parse_payload(Data, MaskKey, Incomplete, UnmaskedLen, Type, Len, FragState, Extensions, Rsv) of {ok, CloseCode, Payload, Utf8State, Rest} -> dispatch_frame(State#state{utf8_state=Utf8State}, HandlerState, ParseState#ps_payload{unmasked= <>, close_code=CloseCode}, Rest); {ok, Payload, Utf8State, Rest} -> dispatch_frame(State#state{utf8_state=Utf8State}, HandlerState, ParseState#ps_payload{unmasked= <>}, Rest); {more, CloseCode, Payload, Utf8State} -> before_loop(State#state{utf8_state=Utf8State}, HandlerState, ParseState#ps_payload{len=Len - byte_size(Data), close_code=CloseCode, unmasked= <>, unmasked_len=UnmaskedLen + byte_size(Data)}); {more, Payload, Utf8State} -> before_loop(State#state{utf8_state=Utf8State}, HandlerState, ParseState#ps_payload{len=Len - byte_size(Data), unmasked= <>, unmasked_len=UnmaskedLen + byte_size(Data)}); Error = {error, _Reason} -> websocket_close(State, HandlerState, Error) end. dispatch_frame(State=#state{socket=Socket, transport=Transport, max_frame_size=MaxFrameSize, frag_state=FragState, frag_buffer=SoFar, extensions=Extensions}, HandlerState, #ps_payload{type=Type0, unmasked=Payload0, close_code=CloseCode0}, RemainingData) -> case cow_ws:make_frame(Type0, Payload0, CloseCode0, FragState) of %% @todo Allow receiving fragments. {fragment, _, _, Payload} when byte_size(Payload) + byte_size(SoFar) > MaxFrameSize -> websocket_close(State, HandlerState, {error, badsize}); {fragment, nofin, _, Payload} -> parse_header(State#state{frag_buffer= << SoFar/binary, Payload/binary >>}, HandlerState, #ps_header{buffer=RemainingData}); {fragment, fin, Type, Payload} -> handler_call(State#state{frag_state=undefined, frag_buffer= <<>>}, HandlerState, #ps_header{buffer=RemainingData}, websocket_handle, {Type, << SoFar/binary, Payload/binary >>}, fun parse_header/3); close -> websocket_close(State, HandlerState, remote); {close, CloseCode, Payload} -> websocket_close(State, HandlerState, {remote, CloseCode, Payload}); Frame = ping -> Transport:send(Socket, cow_ws:frame(pong, Extensions)), handler_call(State, HandlerState, #ps_header{buffer=RemainingData}, websocket_handle, Frame, fun parse_header/3); Frame = {ping, Payload} -> Transport:send(Socket, cow_ws:frame({pong, Payload}, Extensions)), handler_call(State, HandlerState, #ps_header{buffer=RemainingData}, websocket_handle, Frame, fun parse_header/3); Frame -> handler_call(State, HandlerState, #ps_header{buffer=RemainingData}, websocket_handle, Frame, fun parse_header/3) end. handler_call(State=#state{handler=Handler}, HandlerState, ParseState, Callback, Message, NextState) -> try case Callback of websocket_init -> Handler:websocket_init(HandlerState); _ -> Handler:Callback(Message, HandlerState) end of {ok, HandlerState2} -> NextState(State, HandlerState2, ParseState); {ok, HandlerState2, hibernate} -> NextState(State#state{hibernate=true}, HandlerState2, ParseState); {reply, Payload, HandlerState2} -> case websocket_send(Payload, State) of ok -> NextState(State, HandlerState2, ParseState); stop -> terminate(State, HandlerState2, stop); Error = {error, _} -> terminate(State, HandlerState2, Error) end; {reply, Payload, HandlerState2, hibernate} -> case websocket_send(Payload, State) of ok -> NextState(State#state{hibernate=true}, HandlerState2, ParseState); stop -> terminate(State, HandlerState2, stop); Error = {error, _} -> terminate(State, HandlerState2, Error) end; {stop, HandlerState2} -> websocket_close(State, HandlerState2, stop) catch Class:Reason -> websocket_send_close(State, {crash, Class, Reason}), handler_terminate(State, HandlerState, {crash, Class, Reason}), erlang:raise(Class, Reason, erlang:get_stacktrace()) end. -spec websocket_send(cow_ws:frame(), #state{}) -> ok | stop | {error, atom()}. websocket_send(Frames, State) when is_list(Frames) -> websocket_send_many(Frames, State, []); websocket_send(Frame, #state{socket=Socket, transport=Transport, extensions=Extensions}) -> Res = Transport:send(Socket, cow_ws:frame(Frame, Extensions)), case is_close_frame(Frame) of true -> stop; false -> Res end. websocket_send_many([], #state{socket=Socket, transport=Transport}, Acc) -> Transport:send(Socket, lists:reverse(Acc)); websocket_send_many([Frame|Tail], State=#state{socket=Socket, transport=Transport, extensions=Extensions}, Acc0) -> Acc = [cow_ws:frame(Frame, Extensions)|Acc0], case is_close_frame(Frame) of true -> _ = Transport:send(Socket, lists:reverse(Acc)), stop; false -> websocket_send_many(Tail, State, Acc) end. is_close_frame(close) -> true; is_close_frame({close, _}) -> true; is_close_frame({close, _, _}) -> true; is_close_frame(_) -> false. -spec websocket_close(#state{}, any(), terminate_reason()) -> no_return(). websocket_close(State, HandlerState, Reason) -> websocket_send_close(State, Reason), terminate(State, HandlerState, Reason). websocket_send_close(#state{socket=Socket, transport=Transport, extensions=Extensions}, Reason) -> _ = case Reason of Normal when Normal =:= stop; Normal =:= timeout -> Transport:send(Socket, cow_ws:frame({close, 1000, <<>>}, Extensions)); {error, badframe} -> Transport:send(Socket, cow_ws:frame({close, 1002, <<>>}, Extensions)); {error, badencoding} -> Transport:send(Socket, cow_ws:frame({close, 1007, <<>>}, Extensions)); {error, badsize} -> Transport:send(Socket, cow_ws:frame({close, 1009, <<>>}, Extensions)); {crash, _, _} -> Transport:send(Socket, cow_ws:frame({close, 1011, <<>>}, Extensions)); remote -> Transport:send(Socket, cow_ws:frame(close, Extensions)); {remote, Code, _} -> Transport:send(Socket, cow_ws:frame({close, Code, <<>>}, Extensions)) end, ok. -spec terminate(#state{}, any(), terminate_reason()) -> no_return(). terminate(State, HandlerState, Reason) -> handler_terminate(State, HandlerState, Reason), exit(normal). handler_terminate(#state{handler=Handler, req=Req}, HandlerState, Reason) -> cowboy_handler:terminate(Reason, Req, HandlerState, Handler). %% System callbacks. -spec system_continue(_, _, {#state{}, any(), parse_state()}) -> no_return(). system_continue(_, _, {State, HandlerState, ParseState}) -> loop(State, HandlerState, ParseState). -spec system_terminate(any(), _, _, {#state{}, any(), parse_state()}) -> no_return(). system_terminate(Reason, _, _, {State, HandlerState, _}) -> %% @todo We should exit gracefully, if possible. terminate(State, HandlerState, Reason). -spec system_code_change(Misc, _, _, _) -> {ok, Misc} when Misc::{#state{}, any(), parse_state()}. system_code_change(Misc, _, _, _) -> {ok, Misc}.