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Diffstat (limited to 'src/cowboy_http2.erl')
| -rw-r--r-- | src/cowboy_http2.erl | 452 |
1 files changed, 452 insertions, 0 deletions
diff --git a/src/cowboy_http2.erl b/src/cowboy_http2.erl new file mode 100644 index 0000000..e0fe30e --- /dev/null +++ b/src/cowboy_http2.erl @@ -0,0 +1,452 @@ +%% Copyright (c) 2015, 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. + +-module(cowboy_http2). + +-export([init/6]). + +-export([system_continue/3]). +-export([system_terminate/4]). +-export([system_code_change/4]). + +-record(stream, { + id = undefined :: cowboy_stream:streamid(), + state = undefined :: any(), + %% Whether we finished sending data. + local = nofin :: cowboy_stream:fin(), + %% Whether we finished receiving data. + remote = nofin :: cowboy_stream:fin() +}). + +-type stream() :: #stream{}. + +%% @todo priority: if we receive a message for a stream, do a selective receive +%% to get all messages in the mailbox and prioritize them. (later) + +-record(state, { + parent = undefined :: pid(), + ref :: ranch:ref(), + socket = undefined :: inet:socket(), + transport :: module(), + opts = #{} :: map(), + handler :: module(), + + %% Settings are separate for each endpoint. In addition, settings + %% must be acknowledged before they can be expected to be applied. + %% + %% @todo Since the ack is required, we must timeout if we don't receive it. + %% @todo I haven't put as much thought as I should have on this, + %% the final settings handling will be very different. + local_settings = #{} :: map(), + next_settings = #{} :: undefined | map(), %% @todo perhaps set to undefined by default + remote_settings = #{} :: map(), + + %% Stream identifiers. + server_streamid = 2 :: pos_integer(), + %% @todo last known good streamid + + %% Currently active HTTP/2 streams. Streams may be initiated either + %% by the client or by the server through PUSH_PROMISE frames. + streams = [] :: [stream()], + + %% Streams can spawn zero or more children which are then managed + %% by this module if operating as a supervisor. + children = [] :: [{pid(), cowboy_stream:streamid()}], + + %% The client starts by sending a sequence of bytes as a preface, + %% followed by a potentially empty SETTINGS frame. Then the connection + %% is established and continues normally. An exception is when a HEADERS + %% frame is sent followed by CONTINUATION frames: no other frame can be + %% sent in between. + parse_state = preface :: preface | settings | normal + | {continuation, cowboy_stream:streamid(), cowboy_stream:fin(), binary()}, + + %% HPACK decoding and encoding state. + decode_state = cow_hpack:init() :: cow_hpack:state(), + encode_state = cow_hpack:init() :: cow_hpack:state() +}). + +-spec init(pid(), ranch:ref(), inet:socket(), module(), opts(), module()) -> ok. +init(Parent, Ref, Socket, Transport, Opts, Handler) -> + before_loop(#state{parent=Parent, ref=Ref, socket=Socket, + transport=Transport, opts=Opts, handler=Handler}, <<>>). + +%% @todo Add the timeout for last time since we heard of connection. +before_loop(State, Buffer) -> + loop(State, Buffer). + +loop(State=#state{parent=Parent, socket=Socket, transport=Transport, + handler=Handler, children=Children}, Buffer) -> + Transport:setopts(Socket, [{active, once}]), + {OK, Closed, Error} = Transport:messages(), + receive + %% Socket messages. + {OK, Socket, Data} -> + parse(State, << Buffer/binary, Data/binary >>); + {Closed, Socket} -> + terminate(State, {socket_error, closed, 'The socket has been closed.'}); + {Error, Socket, Reason} -> + terminate(State, {socket_error, Reason, 'An error has occurred on the socket.'}); + %% System messages. + {'EXIT', Parent, Reason} -> + exit(Reason); + {system, From, Request} -> + sys:handle_system_msg(Request, From, Parent, ?MODULE, [], {State, Buffer}); + %% Messages pertaining to a stream. + {{Handler, StreamID}, Msg} -> + loop(info(State, StreamID, Msg), Buffer); + %% Exit signal from children. + Msg = {'EXIT', Pid, _} -> + loop(down(State, Pid, Msg), Buffer); + %% Calls from supervisor module. + {'$gen_call', {From, Tag}, which_children} -> + Workers = [{?MODULE, Pid, worker, [?MODULE]} || {Pid, _} <- Children], + From ! {Tag, Workers}, + loop(State, Buffer); + {'$gen_call', {From, Tag}, count_children} -> + NbChildren = length(Children), + Counts = [{specs, 1}, {active, NbChildren}, + {supervisors, 0}, {workers, NbChildren}], + From ! {Tag, Counts}, + loop(State, Buffer); + {'$gen_call', {From, Tag}, _} -> + From ! {Tag, {error, ?MODULE}}, + loop(State, Buffer); + Msg -> + error_logger:error_msg("Received stray message ~p.", [Msg]), + loop(State, Buffer) + %% @todo Configurable timeout. + after 60000 -> + terminate(State, {internal_error, timeout, 'No message or data received before timeout.'}) + end. + +parse(State=#state{socket=Socket, transport=Transport, next_settings=Settings, parse_state=preface}, Data) -> + case Data of + << "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n", Rest/bits >> -> + %% @todo To speed up connection we may be able to construct the frame when starting the listener. + %% We send next_settings and use defaults until we get a ack. + Transport:send(Socket, cow_http2:settings(Settings)), + parse(State#state{parse_state=settings}, Rest); + _ when byte_size(Data) >= 24 -> + Transport:close(Socket), + exit({shutdown, {connection_error, protocol_error, + 'The connection preface was invalid. (RFC7540 3.5)'}}); + _ -> + before_loop(State, Data) + end; +%% @todo Perhaps instead of just more we can have {more, Len} to avoid all the checks. +parse(State=#state{parse_state=ParseState}, Data) -> + case cow_http2:parse(Data) of + {ok, Frame, Rest} -> + case ParseState of + normal -> parse(frame(State, Frame), Rest); + settings -> parse(frame(State, Frame), Rest); + _ -> parse(continuation_frame(State, Frame), Rest) + end; + {stream_error, StreamID, Reason, Human, Rest} -> + parse(stream_reset(State, StreamID, {stream_error, Reason, Human}), Rest); + Error = {connection_error, _, _} -> + terminate(State, Error); + more -> + before_loop(State, Data) + end. + +%% @todo When we get a 'fin' we need to check if the stream had a 'fin' sent back +%% and terminate the stream if this is the end of it. + +%% DATA frame. +frame(State=#state{handler=Handler, streams=Streams0}, {data, StreamID, IsFin, Data}) -> + case lists:keyfind(StreamID, #stream.id, Streams0) of + Stream = #stream{state=StreamState0} -> %% @todo in=open + try Handler:data(StreamID, IsFin, Data, StreamState0) of + {Commands, StreamState} -> + Streams = lists:keyreplace(StreamID, #stream.id, Streams0, + Stream#stream{state=StreamState}), + commands(State#state{streams=Streams}, StreamID, Commands) + catch Class:Reason -> + error_logger:error_msg("Exception occurred in ~s:data(~p, ~p, ~p, ~p) with reason ~p:~p.", + [Handler, StreamID, IsFin, Data, StreamState0, Class, Reason]), + stream_reset(State, StreamID, {internal_error, {Class, Reason}, + 'Exception occurred in StreamHandler:data/4 call.'}) + end; + false -> + stream_reset(State, StreamID, {stream_error, stream_closed, + 'DATA frame received for a closed or non-existent stream. (RFC7540 6.1)'}) + end; +%% Single HEADERS frame headers block. +frame(State, {headers, StreamID, IsFin, head_fin, HeaderBlock}) -> + %% @todo We probably need to validate StreamID here and in 4 next clauses. + stream_init(State, StreamID, IsFin, HeaderBlock); +%% HEADERS frame starting a headers block. Enter continuation mode. +frame(State, {headers, StreamID, IsFin, head_nofin, HeaderBlockFragment}) -> + State#state{parse_state={continuation, StreamID, IsFin, HeaderBlockFragment}}; +%% Single HEADERS frame headers block with priority. +frame(State, {headers, StreamID, IsFin, head_fin, + _IsExclusive, _DepStreamID, _Weight, HeaderBlock}) -> + %% @todo Handle priority. + stream_init(State, StreamID, IsFin, HeaderBlock); +%% HEADERS frame starting a headers block. Enter continuation mode. +frame(State, {headers, StreamID, IsFin, head_nofin, + _IsExclusive, _DepStreamID, _Weight, HeaderBlockFragment}) -> + %% @todo Handle priority. + State#state{parse_state={continuation, StreamID, IsFin, HeaderBlockFragment}}; +%% PRIORITY frame. +frame(State, {priority, _StreamID, _IsExclusive, _DepStreamID, _Weight}) -> + %% @todo Validate StreamID? + %% @todo Handle priority. + State; +%% RST_STREAM frame. +frame(State, {rst_stream, StreamID, Reason}) -> + stream_reset(State, StreamID, {stream_error, Reason, 'Stream reset requested by client.'}); +%% SETTINGS frame. +frame(State, {settings, Settings}) -> + %% @todo Apply SETTINGS. + io:format("settings ~p~n", [Settings]), + State; +%% Ack for a previously sent SETTINGS frame. +frame(State=#state{next_settings=_NextSettings}, settings_ack) -> + %% @todo Apply SETTINGS that require synchronization. + State; +%% Unexpected PUSH_PROMISE frame. +frame(State, {push_promise, _, _, _, _}) -> + terminate(State, {connection_error, protocol_error, + 'PUSH_PROMISE frames MUST only be sent on a peer-initiated stream. (RFC7540 6.6)'}); +%% PING frame. +frame(State=#state{socket=Socket, transport=Transport}, {ping, Opaque}) -> + Transport:send(Socket, cow_http2:ping_ack(Opaque)), + State; +%% Ack for a previously sent PING frame. +%% +%% @todo Might want to check contents but probably a waste of time. +frame(State, {ping_ack, _Opaque}) -> + State; +%% GOAWAY frame. +frame(State, Frame={goaway, _, _, _}) -> + terminate(State, {stop, Frame, 'Client is going away.'}); +%% Connection-wide WINDOW_UPDATE frame. +frame(State, {window_update, _Increment}) -> + %% @todo control flow + State; +%% Stream-specific WINDOW_UPDATE frame. +frame(State, {window_update, _StreamID, _Increment}) -> + %% @todo stream-specific control flow + State; +%% Unexpected CONTINUATION frame. +frame(State, {continuation, _, _, _}) -> + terminate(State, {connection_error, protocol_error, + 'CONTINUATION frames MUST be preceded by a HEADERS frame. (RFC7540 6.10)'}). + +continuation_frame(State=#state{parse_state={continuation, StreamID, IsFin, HeaderBlockFragment0}}, + {continuation, StreamID, fin, HeaderBlockFragment1}) -> + stream_init(State#state{parse_state=normal}, StreamID, IsFin, + << HeaderBlockFragment0/binary, HeaderBlockFragment1/binary >>); +continuation_frame(State=#state{parse_state={continuation, StreamID, IsFin, HeaderBlockFragment0}}, + {continuation, StreamID, nofin, HeaderBlockFragment1}) -> + State#state{parse_state={continuation, StreamID, IsFin, + << HeaderBlockFragment0/binary, HeaderBlockFragment1/binary >>}}; +continuation_frame(State, _) -> + terminate(State, {connection_error, protocol_error, + 'An invalid frame was received while expecting a CONTINUATION frame. (RFC7540 6.2)'}). + +down(State=#state{children=Children0}, Pid, Msg) -> + case lists:keytake(Pid, 1, Children0) of + {value, {_, StreamID}, Children} -> + info(State#state{children=Children}, StreamID, Msg); + false -> + error_logger:error_msg("Received EXIT signal ~p for unknown process ~p.", [Msg, Pid]), + State + end. + +info(State=#state{handler=Handler, streams=Streams0}, StreamID, Msg) -> + case lists:keyfind(StreamID, #stream.id, Streams0) of + Stream = #stream{state=StreamState0} -> + try Handler:info(StreamID, Msg, StreamState0) of + {Commands, StreamState} -> + Streams = lists:keyreplace(StreamID, #stream.id, Streams0, + Stream#stream{state=StreamState}), + commands(State#state{streams=Streams}, StreamID, Commands) + catch Class:Reason -> + error_logger:error_msg("Exception occurred in ~s:info(~p, ~p, ~p) with reason ~p:~p.", + [Handler, StreamID, Msg, StreamState0, Class, Reason]), + stream_reset(State, StreamID, {internal_error, {Class, Reason}, + 'Exception occurred in StreamHandler:info/3 call.'}) + end; + false -> + error_logger:error_msg("Received message ~p for unknown stream ~p.", [Msg, StreamID]), + State + end. + +commands(State, _, []) -> + State; +%% Send response headers. +%% +%% @todo Kill the stream if it sent a response when one has already been sent. +%% @todo Keep IsFin in the state. +%% @todo Same two things above apply to DATA, possibly promise too. +commands(State=#state{socket=Socket, transport=Transport, encode_state=EncodeState0}, StreamID, + [{response, IsFin, StatusCode, Headers0}|Tail]) -> + Headers = Headers0#{<<":status">> => integer_to_binary(StatusCode)}, + {HeaderBlock, EncodeState} = headers_encode(Headers, EncodeState0), + Transport:send(Socket, cow_http2:headers(StreamID, IsFin, HeaderBlock)), + commands(State#state{encode_state=EncodeState}, StreamID, Tail); +%% Send a response body chunk. +%% +%% @todo WINDOW_UPDATE stuff require us to buffer some data. +commands(State=#state{socket=Socket, transport=Transport}, StreamID, + [{data, IsFin, Data}|Tail]) -> + Transport:send(Socket, cow_http2:data(StreamID, IsFin, Data)), + commands(State, StreamID, Tail); +%% Send a push promise. +%% +%% @todo We need to keep track of what promises we made so that we don't +%% end up with an infinite loop of promises. +commands(State0=#state{socket=Socket, transport=Transport, server_streamid=PromisedStreamID, + encode_state=EncodeState0}, StreamID, + [{promise, Method, Scheme, Authority, Path, Headers0}|Tail]) -> + Headers = Headers0#{<<":method">> => Method, + <<":scheme">> => Scheme, + <<":authority">> => Authority, + <<":path">> => Path}, + {HeaderBlock, EncodeState} = headers_encode(Headers, EncodeState0), + Transport:send(Socket, cow_http2:push_promise(StreamID, PromisedStreamID, HeaderBlock)), + %% @todo iolist_to_binary(HeaderBlock) isn't optimal. Need a shortcut. + State = stream_init(State0#state{server_streamid=PromisedStreamID + 2, encode_state=EncodeState}, + PromisedStreamID, fin, iolist_to_binary(HeaderBlock)), + commands(State, StreamID, Tail); +%% @todo Update the flow control state. +commands(State, StreamID, [{flow, _Size}|Tail]) -> + commands(State, StreamID, Tail); +%% Supervise a child process. +commands(State=#state{children=Children}, StreamID, [{spawn, Pid}|Tail]) -> + commands(State#state{children=[{Pid, StreamID}|Children]}, StreamID, Tail); +%% Upgrade to a new protocol. +%% +%% @todo Implementation. +%% @todo Can only upgrade if: there are no other streams and there are no children left alive. +%% @todo For HTTP/1.1 we should reject upgrading if pipelining is used. +commands(State, StreamID, [{upgrade, _Mod, _ModState}]) -> + commands(State, StreamID, []); +commands(State, StreamID, [{upgrade, _Mod, _ModState}|Tail]) -> + %% @todo This is an error. Not sure what to do here yet. + commands(State, StreamID, Tail). + +terminate(#state{socket=Socket, transport=Transport, handler=Handler, + streams=Streams, children=Children}, Reason) -> + %% @todo Send GOAWAY frame; need to keep track of last good stream id; how? + terminate_all_streams(Streams, Reason, Handler, Children), + Transport:close(Socket), + exit({shutdown, Reason}). + +terminate_all_streams([], _, _, []) -> + ok; +terminate_all_streams([#stream{id=StreamID, state=StreamState}|Tail], Reason, Handler, Children0) -> + stream_call_terminate(StreamID, Reason, Handler, StreamState), + Children = stream_terminate_children(Children0, StreamID, []), + terminate_all_streams(Tail, Reason, Handler, Children). + +%% Stream functions. + +stream_init(State0=#state{socket=Socket, transport=Transport, handler=Handler, + streams=Streams0, decode_state=DecodeState0}, StreamID, IsFin, HeaderBlock) -> + %% @todo Add clause for CONNECT requests (no scheme/path). + try headers_decode(HeaderBlock, DecodeState0) of + {Headers0=#{ + <<":method">> := Method, + <<":scheme">> := Scheme, + <<":authority">> := Authority, + <<":path">> := Path}, DecodeState} -> + State = State0#state{decode_state=DecodeState}, + Headers = maps:without([<<":method">>, <<":scheme">>, <<":authority">>, <<":path">>], Headers0), + try Handler:init(StreamID, IsFin, Method, Scheme, Authority, Path, Headers) of + {Commands, StreamState} -> + Streams = [#stream{id=StreamID, state=StreamState}|Streams0], + commands(State#state{streams=Streams}, StreamID, Commands) + catch Class:Reason -> + error_logger:error_msg("Exception occurred in ~s:init(~p, ~p, ~p, ~p, ~p, ~p, ~p) " + "with reason ~p:~p.", + [Handler, StreamID, IsFin, Method, Scheme, Authority, Path, Headers, Class, Reason]), + stream_reset(State, StreamID, {internal_error, {Class, Reason}, + 'Exception occurred in StreamHandler:init/7 call.'}) + end; + {_, DecodeState} -> + Transport:send(Socket, cow_http2:rst_stream(StreamID, protocol_error)), + State0#state{decode_state=DecodeState} + catch _:_ -> + terminate(State0, {connection_error, compression_error, + 'Error while trying to decode HPACK-encoded header block. (RFC7540 4.3)'}) + end. + +%% @todo We might need to keep track of which stream has been reset so we don't send lots of them. +stream_reset(State=#state{socket=Socket, transport=Transport}, StreamID, + StreamError={internal_error, _, _}) -> + Transport:send(Socket, cow_http2:rst_stream(StreamID, internal_error)), + stream_terminate(State, StreamID, StreamError); +stream_reset(State=#state{socket=Socket, transport=Transport}, StreamID, + StreamError={stream_error, Reason, _}) -> + Transport:send(Socket, cow_http2:rst_stream(StreamID, Reason)), + stream_terminate(State, StreamID, StreamError). + +stream_terminate(State=#state{handler=Handler, streams=Streams0, children=Children0}, StreamID, Reason) -> + case lists:keytake(StreamID, #stream.id, Streams0) of + {value, #stream{state=StreamState}, Streams} -> + stream_call_terminate(StreamID, Reason, Handler, StreamState), + Children = stream_terminate_children(Children0, StreamID, []), + State#state{streams=Streams, children=Children}; + false -> + %% @todo Unknown stream. Not sure what to do here. Check again once all + %% terminate calls have been written. + State + end. + +stream_call_terminate(StreamID, Reason, Handler, StreamState) -> + try + Handler:terminate(StreamID, Reason, StreamState), + ok + catch Class:Reason -> + error_logger:error_msg("Exception occurred in ~s:terminate(~p, ~p, ~p) with reason ~p:~p.", + [Handler, StreamID, Reason, StreamState, Class, Reason]) + end. + +stream_terminate_children([], _, Acc) -> + Acc; +stream_terminate_children([{Pid, StreamID}|Tail], StreamID, Acc) -> + exit(Pid, kill), + stream_terminate_children(Tail, StreamID, Acc); +stream_terminate_children([Child|Tail], StreamID, Acc) -> + stream_terminate_children(Tail, StreamID, [Child|Acc]). + +%% Headers encode/decode. + +headers_decode(HeaderBlock, DecodeState0) -> + {Headers, DecodeState} = cow_hpack:decode(HeaderBlock, DecodeState0), + {maps:from_list(Headers), DecodeState}. + +%% @todo We will need to special-case the set-cookie header here. +headers_encode(Headers0, EncodeState) -> + Headers = maps:to_list(Headers0), + cow_hpack:encode(Headers, EncodeState). + +%% System callbacks. + +-spec system_continue(_, _, #state{}) -> ok. +system_continue(_, _, {State, Buffer}) -> + loop(State, Buffer). + +-spec system_terminate(any(), _, _, _) -> no_return(). +system_terminate(Reason, _, _, _) -> + exit(Reason). + +-spec system_code_change(Misc, _, _, _) -> {ok, Misc} when Misc::{#state{}, binary()}. +system_code_change(Misc, _, _, _) -> + {ok, Misc}. |