%% Copyright (c) 2015-2017, 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).
-ifdef(OTP_RELEASE).
-compile({nowarn_deprecated_function, [{erlang, get_stacktrace, 0}]}).
-endif.
-export([init/6]).
-export([init/10]).
-export([init/12]).
-export([system_continue/3]).
-export([system_terminate/4]).
-export([system_code_change/4]).
-type opts() :: #{
compress_buffering => boolean(),
compress_threshold => non_neg_integer(),
connection_type => worker | supervisor,
connection_window_margin_size => 0..16#7fffffff,
connection_window_update_threshold => 0..16#7fffffff,
enable_connect_protocol => boolean(),
env => cowboy_middleware:env(),
idle_timeout => timeout(),
inactivity_timeout => timeout(),
initial_connection_window_size => 65535..16#7fffffff,
initial_stream_window_size => 0..16#7fffffff,
logger => module(),
max_concurrent_streams => non_neg_integer() | infinity,
max_connection_buffer_size => non_neg_integer(),
max_connection_window_size => 0..16#7fffffff,
max_decode_table_size => non_neg_integer(),
max_encode_table_size => non_neg_integer(),
max_frame_size_received => 16384..16777215,
max_frame_size_sent => 16384..16777215 | infinity,
max_received_frame_rate => {pos_integer(), timeout()},
max_reset_stream_rate => {pos_integer(), timeout()},
max_stream_buffer_size => non_neg_integer(),
max_stream_window_size => 0..16#7fffffff,
metrics_callback => cowboy_metrics_h:metrics_callback(),
metrics_req_filter => fun((cowboy_req:req()) -> map()),
metrics_resp_headers_filter => fun((cowboy:http_headers()) -> cowboy:http_headers()),
middlewares => [module()],
preface_timeout => timeout(),
proxy_header => boolean(),
sendfile => boolean(),
settings_timeout => timeout(),
shutdown_timeout => timeout(),
stream_handlers => [module()],
stream_window_data_threshold => 0..16#7fffffff,
stream_window_margin_size => 0..16#7fffffff,
stream_window_update_threshold => 0..16#7fffffff,
tracer_callback => cowboy_tracer_h:tracer_callback(),
tracer_flags => [atom()],
tracer_match_specs => cowboy_tracer_h:tracer_match_specs(),
%% Open ended because configured stream handlers might add options.
_ => _
}.
-export_type([opts/0]).
-record(stream, {
%% Whether the stream is currently stopping.
status = running :: running | stopping,
%% Flow requested for this stream.
flow = 0 :: non_neg_integer(),
%% Stream state.
state :: {module, any()}
}).
-record(state, {
parent = undefined :: pid(),
ref :: ranch:ref(),
socket = undefined :: inet:socket(),
transport :: module(),
proxy_header :: undefined | ranch_proxy_header:proxy_info(),
opts = #{} :: opts(),
%% Timer for idle_timeout.
timer = undefined :: undefined | reference(),
%% Remote address and port for the connection.
peer = undefined :: {inet:ip_address(), inet:port_number()},
%% Local address and port for the connection.
sock = undefined :: {inet:ip_address(), inet:port_number()},
%% Client certificate (TLS only).
cert :: undefined | binary(),
%% HTTP/2 state machine.
http2_status :: sequence | settings | upgrade | connected | closing,
http2_machine :: cow_http2_machine:http2_machine(),
%% HTTP/2 frame rate flood protection.
frame_rate_num :: undefined | pos_integer(),
frame_rate_time :: undefined | integer(),
%% HTTP/2 reset stream flood protection.
reset_rate_num :: undefined | pos_integer(),
reset_rate_time :: undefined | integer(),
%% Flow requested for all streams.
flow = 0 :: non_neg_integer(),
%% Currently active HTTP/2 streams. Streams may be initiated either
%% by the client or by the server through PUSH_PROMISE frames.
streams = #{} :: #{cow_http2:streamid() => #stream{}},
%% Streams can spawn zero or more children which are then managed
%% by this module if operating as a supervisor.
children = cowboy_children:init() :: cowboy_children:children()
}).
-spec init(pid(), ranch:ref(), inet:socket(), module(),
ranch_proxy_header:proxy_info() | undefined, cowboy:opts()) -> ok.
init(Parent, Ref, Socket, Transport, ProxyHeader, Opts) ->
Peer0 = Transport:peername(Socket),
Sock0 = Transport:sockname(Socket),
Cert1 = case Transport:name() of
ssl ->
case ssl:peercert(Socket) of
{error, no_peercert} ->
{ok, undefined};
Cert0 ->
Cert0
end;
_ ->
{ok, undefined}
end,
case {Peer0, Sock0, Cert1} of
{{ok, Peer}, {ok, Sock}, {ok, Cert}} ->
init(Parent, Ref, Socket, Transport, ProxyHeader, Opts, Peer, Sock, Cert, <<>>);
{{error, Reason}, _, _} ->
terminate(undefined, {socket_error, Reason,
'A socket error occurred when retrieving the peer name.'});
{_, {error, Reason}, _} ->
terminate(undefined, {socket_error, Reason,
'A socket error occurred when retrieving the sock name.'});
{_, _, {error, Reason}} ->
terminate(undefined, {socket_error, Reason,
'A socket error occurred when retrieving the client TLS certificate.'})
end.
-spec init(pid(), ranch:ref(), inet:socket(), module(),
ranch_proxy_header:proxy_info() | undefined, cowboy:opts(),
{inet:ip_address(), inet:port_number()}, {inet:ip_address(), inet:port_number()},
binary() | undefined, binary()) -> ok.
init(Parent, Ref, Socket, Transport, ProxyHeader, Opts, Peer, Sock, Cert, Buffer) ->
{ok, Preface, HTTP2Machine} = cow_http2_machine:init(server, Opts),
State = set_timeout(init_rate_limiting(#state{parent=Parent, ref=Ref, socket=Socket,
transport=Transport, proxy_header=ProxyHeader,
opts=Opts, peer=Peer, sock=Sock, cert=Cert,
http2_status=sequence, http2_machine=HTTP2Machine})),
Transport:send(Socket, Preface),
case Buffer of
<<>> -> loop(State, Buffer);
_ -> parse(State, Buffer)
end.
init_rate_limiting(State=#state{opts=Opts}) ->
{FrameRateNum, FrameRatePeriod} = maps:get(max_received_frame_rate, Opts, {1000, 10000}),
{ResetRateNum, ResetRatePeriod} = maps:get(max_reset_stream_rate, Opts, {10, 10000}),
CurrentTime = erlang:monotonic_time(millisecond),
State#state{
frame_rate_num=FrameRateNum, frame_rate_time=add_period(CurrentTime, FrameRatePeriod),
reset_rate_num=ResetRateNum, reset_rate_time=add_period(CurrentTime, ResetRatePeriod)
}.
add_period(_, infinity) -> infinity;
add_period(Time, Period) -> Time + Period.
%% @todo Add an argument for the request body.
-spec init(pid(), ranch:ref(), inet:socket(), module(),
ranch_proxy_header:proxy_info() | undefined, cowboy:opts(),
{inet:ip_address(), inet:port_number()}, {inet:ip_address(), inet:port_number()},
binary() | undefined, binary(), map() | undefined, cowboy_req:req()) -> ok.
init(Parent, Ref, Socket, Transport, ProxyHeader, Opts, Peer, Sock, Cert, Buffer,
_Settings, Req=#{method := Method}) ->
{ok, Preface, HTTP2Machine0} = cow_http2_machine:init(server, Opts),
{ok, StreamID, HTTP2Machine}
= cow_http2_machine:init_upgrade_stream(Method, HTTP2Machine0),
State0 = #state{parent=Parent, ref=Ref, socket=Socket,
transport=Transport, proxy_header=ProxyHeader,
opts=Opts, peer=Peer, sock=Sock, cert=Cert,
http2_status=upgrade, http2_machine=HTTP2Machine},
State1 = headers_frame(State0#state{
http2_machine=HTTP2Machine}, StreamID, Req),
%% We assume that the upgrade will be applied. A stream handler
%% must not prevent the normal operations of the server.
State2 = info(State1, 1, {switch_protocol, #{
<<"connection">> => <<"Upgrade">>,
<<"upgrade">> => <<"h2c">>
}, ?MODULE, undefined}), %% @todo undefined or #{}?
State = set_timeout(init_rate_limiting(State2#state{http2_status=sequence})),
Transport:send(Socket, Preface),
case Buffer of
<<>> -> loop(State, Buffer);
_ -> parse(State, Buffer)
end.
loop(State=#state{parent=Parent, socket=Socket, transport=Transport,
opts=Opts, timer=TimerRef, children=Children}, Buffer) ->
%% @todo This should only be called when data was read.
Transport:setopts(Socket, [{active, once}]),
Messages = Transport:messages(),
InactivityTimeout = maps:get(inactivity_timeout, Opts, 300000),
receive
%% Socket messages.
{OK, Socket, Data} when OK =:= element(1, Messages) ->
parse(set_timeout(State), << Buffer/binary, Data/binary >>);
{Closed, Socket} when Closed =:= element(2, Messages) ->
terminate(State, {socket_error, closed, 'The socket has been closed.'});
{Error, Socket, Reason} when Error =:= element(3, Messages) ->
terminate(State, {socket_error, Reason, 'An error has occurred on the socket.'});
%% System messages.
{'EXIT', Parent, Reason} ->
%% @todo Graceful shutdown here as well?
terminate(State, {stop, {exit, Reason}, 'Parent process terminated.'});
{system, From, Request} ->
sys:handle_system_msg(Request, From, Parent, ?MODULE, [], {State, Buffer});
%% Timeouts.
{timeout, TimerRef, idle_timeout} ->
terminate(State, {stop, timeout,
'Connection idle longer than configuration allows.'});
{timeout, Ref, {shutdown, Pid}} ->
cowboy_children:shutdown_timeout(Children, Ref, Pid),
loop(State, Buffer);
{timeout, TRef, {cow_http2_machine, Name}} ->
loop(timeout(State, Name, TRef), Buffer);
%% Messages pertaining to a stream.
{{Pid, StreamID}, Msg} when Pid =:= self() ->
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, Call} ->
cowboy_children:handle_supervisor_call(Call, From, Children, ?MODULE),
loop(State, Buffer);
Msg ->
cowboy:log(warning, "Received stray message ~p.", [Msg], Opts),
loop(State, Buffer)
after InactivityTimeout ->
terminate(State, {internal_error, timeout, 'No message or data received before timeout.'})
end.
set_timeout(State=#state{opts=Opts, timer=TimerRef0}) ->
ok = case TimerRef0 of
undefined -> ok;
_ -> erlang:cancel_timer(TimerRef0, [{async, true}, {info, false}])
end,
TimerRef = case maps:get(idle_timeout, Opts, 60000) of
infinity -> undefined;
Timeout -> erlang:start_timer(Timeout, self(), idle_timeout)
end,
State#state{timer=TimerRef}.
%% HTTP/2 protocol parsing.
parse(State=#state{http2_status=sequence}, Data) ->
case cow_http2:parse_sequence(Data) of
{ok, Rest} ->
parse(State#state{http2_status=settings}, Rest);
more ->
loop(State, Data);
Error = {connection_error, _, _} ->
terminate(State, Error)
end;
parse(State=#state{http2_status=Status, http2_machine=HTTP2Machine, streams=Streams}, Data) ->
MaxFrameSize = cow_http2_machine:get_local_setting(max_frame_size, HTTP2Machine),
case cow_http2:parse(Data, MaxFrameSize) of
{ok, Frame, Rest} ->
parse(frame_rate(State, Frame), Rest);
{ignore, Rest} ->
parse(frame_rate(State, ignore), Rest);
{stream_error, StreamID, Reason, Human, Rest} ->
parse(reset_stream(State, StreamID, {stream_error, Reason, Human}), Rest);
Error = {connection_error, _, _} ->
terminate(State, Error);
%% Terminate the connection if we are closing and all streams have completed.
more when Status =:= closing, Streams =:= #{} ->
terminate(State, {stop, normal, 'The connection is going away.'});
more ->
loop(State, Data)
end.
%% Frame rate flood protection.
frame_rate(State0=#state{opts=Opts, frame_rate_num=Num0, frame_rate_time=Time}, Frame) ->
{Result, State} = case Num0 - 1 of
0 ->
CurrentTime = erlang:monotonic_time(millisecond),
if
CurrentTime < Time ->
{error, State0};
true ->
%% When the option has a period of infinity we cannot reach this clause.
{Num, Period} = maps:get(max_received_frame_rate, Opts, {1000, 10000}),
{ok, State0#state{frame_rate_num=Num, frame_rate_time=CurrentTime + Period}}
end;
Num ->
{ok, State0#state{frame_rate_num=Num}}
end,
case {Result, Frame} of
{ok, ignore} -> ignored_frame(State);
{ok, _} -> frame(State, Frame);
{error, _} -> terminate(State, {connection_error, enhance_your_calm,
'Frame rate larger than configuration allows. Flood? (CVE-2019-9512, CVE-2019-9515, CVE-2019-9518)'})
end.
%% Frames received.
%% We do nothing when receiving a lingering DATA frame.
%% We already removed the stream flow from the connection
%% flow and are therefore already accounting for the window
%% being reduced by these frames.
frame(State=#state{http2_machine=HTTP2Machine0}, Frame) ->
case cow_http2_machine:frame(Frame, HTTP2Machine0) of
{ok, HTTP2Machine} ->
maybe_ack(State#state{http2_machine=HTTP2Machine}, Frame);
{ok, {data, StreamID, IsFin, Data}, HTTP2Machine} ->
data_frame(State#state{http2_machine=HTTP2Machine}, StreamID, IsFin, Data);
{ok, {headers, StreamID, IsFin, Headers, PseudoHeaders, BodyLen}, HTTP2Machine} ->
headers_frame(State#state{http2_machine=HTTP2Machine},
StreamID, IsFin, Headers, PseudoHeaders, BodyLen);
{ok, {trailers, _StreamID, _Trailers}, HTTP2Machine} ->
%% @todo Propagate trailers.
State#state{http2_machine=HTTP2Machine};
{ok, {rst_stream, StreamID, Reason}, HTTP2Machine} ->
rst_stream_frame(State#state{http2_machine=HTTP2Machine}, StreamID, Reason);
{ok, GoAway={goaway, _, _, _}, HTTP2Machine} ->
goaway(State#state{http2_machine=HTTP2Machine}, GoAway);
{send, SendData, HTTP2Machine} ->
%% We may need to send an alarm for each of the streams sending data.
lists:foldl(
fun({StreamID, _, _}, S) -> maybe_send_data_alarm(S, HTTP2Machine0, StreamID) end,
send_data(maybe_ack(State#state{http2_machine=HTTP2Machine}, Frame), SendData),
SendData);
{error, {stream_error, StreamID, Reason, Human}, HTTP2Machine} ->
reset_stream(State#state{http2_machine=HTTP2Machine},
StreamID, {stream_error, Reason, Human});
{error, Error={connection_error, _, _}, HTTP2Machine} ->
terminate(State#state{http2_machine=HTTP2Machine}, Error)
end.
%% We use this opportunity to mark the HTTP/2 status as connected
%% if we were still waiting for a SETTINGS frame.
maybe_ack(State=#state{http2_status=settings}, Frame) ->
maybe_ack(State#state{http2_status=connected}, Frame);
maybe_ack(State=#state{socket=Socket, transport=Transport}, Frame) ->
case Frame of
{settings, _} -> Transport:send(Socket, cow_http2:settings_ack());
{ping, Opaque} -> Transport:send(Socket, cow_http2:ping_ack(Opaque));
_ -> ok
end,
State.
data_frame(State0=#state{opts=Opts, flow=Flow, streams=Streams}, StreamID, IsFin, Data) ->
case Streams of
#{StreamID := Stream=#stream{status=running, flow=StreamFlow, state=StreamState0}} ->
try cowboy_stream:data(StreamID, IsFin, Data, StreamState0) of
{Commands, StreamState} ->
%% Remove the amount of data received from the flow.
%% We may receive more data than we requested. We ensure
%% that the flow value doesn't go lower than 0.
Size = byte_size(Data),
State = update_window(State0#state{flow=max(0, Flow - Size),
streams=Streams#{StreamID => Stream#stream{
flow=max(0, StreamFlow - Size), state=StreamState}}},
StreamID),
commands(State, StreamID, Commands)
catch Class:Exception ->
cowboy:log(cowboy_stream:make_error_log(data,
[StreamID, IsFin, Data, StreamState0],
Class, Exception, erlang:get_stacktrace()), Opts),
reset_stream(State0, StreamID, {internal_error, {Class, Exception},
'Unhandled exception in cowboy_stream:data/4.'})
end;
%% We ignore DATA frames for streams that are stopping.
#{} ->
State0
end.
headers_frame(State, StreamID, IsFin, Headers,
PseudoHeaders=#{method := <<"CONNECT">>}, _)
when map_size(PseudoHeaders) =:= 2 ->
early_error(State, StreamID, IsFin, Headers, PseudoHeaders, 501,
'The CONNECT method is currently not implemented. (RFC7231 4.3.6)');
headers_frame(State, StreamID, IsFin, Headers,
PseudoHeaders=#{method := <<"TRACE">>}, _) ->
early_error(State, StreamID, IsFin, Headers, PseudoHeaders, 501,
'The TRACE method is currently not implemented. (RFC7231 4.3.8)');
headers_frame(State, StreamID, IsFin, Headers, PseudoHeaders=#{authority := Authority}, BodyLen) ->
headers_frame_parse_host(State, StreamID, IsFin, Headers, PseudoHeaders, BodyLen, Authority);
headers_frame(State, StreamID, IsFin, Headers, PseudoHeaders, BodyLen) ->
case lists:keyfind(<<"host">>, 1, Headers) of
{_, Authority} ->
headers_frame_parse_host(State, StreamID, IsFin, Headers, PseudoHeaders, BodyLen, Authority);
_ ->
reset_stream(State, StreamID, {stream_error, protocol_error,
'Requests translated from HTTP/1.1 must include a host header. (RFC7540 8.1.2.3, RFC7230 5.4)'})
end.
headers_frame_parse_host(State=#state{ref=Ref, peer=Peer, sock=Sock, cert=Cert, proxy_header=ProxyHeader},
StreamID, IsFin, Headers, PseudoHeaders=#{method := Method, scheme := Scheme, path := PathWithQs},
BodyLen, Authority) ->
try cow_http_hd:parse_host(Authority) of
{Host, Port0} ->
Port = ensure_port(Scheme, Port0),
try cow_http:parse_fullpath(PathWithQs) of
{<<>>, _} ->
reset_stream(State, StreamID, {stream_error, protocol_error,
'The path component must not be empty. (RFC7540 8.1.2.3)'});
{Path, Qs} ->
Req0 = #{
ref => Ref,
pid => self(),
streamid => StreamID,
peer => Peer,
sock => Sock,
cert => Cert,
method => Method,
scheme => Scheme,
host => Host,
port => Port,
path => Path,
qs => Qs,
version => 'HTTP/2',
headers => headers_to_map(Headers, #{}),
has_body => IsFin =:= nofin,
body_length => BodyLen
},
%% We add the PROXY header information if any.
Req1 = case ProxyHeader of
undefined -> Req0;
_ -> Req0#{proxy_header => ProxyHeader}
end,
%% We add the protocol information for extended CONNECTs.
Req = case PseudoHeaders of
#{protocol := Protocol} -> Req1#{protocol => Protocol};
_ -> Req1
end,
headers_frame(State, StreamID, Req)
catch _:_ ->
reset_stream(State, StreamID, {stream_error, protocol_error,
'The :path pseudo-header is invalid. (RFC7540 8.1.2.3)'})
end
catch _:_ ->
reset_stream(State, StreamID, {stream_error, protocol_error,
'The :authority pseudo-header is invalid. (RFC7540 8.1.2.3)'})
end.
ensure_port(<<"http">>, undefined) -> 80;
ensure_port(<<"https">>, undefined) -> 443;
ensure_port(_, Port) -> Port.
%% This function is necessary to properly handle duplicate headers
%% and the special-case cookie header.
headers_to_map([], Acc) ->
Acc;
headers_to_map([{Name, Value}|Tail], Acc0) ->
Acc = case Acc0 of
%% The cookie header does not use proper HTTP header lists.
#{Name := Value0} when Name =:= <<"cookie">> ->
Acc0#{Name => << Value0/binary, "; ", Value/binary >>};
#{Name := Value0} ->
Acc0#{Name => << Value0/binary, ", ", Value/binary >>};
_ ->
Acc0#{Name => Value}
end,
headers_to_map(Tail, Acc).
headers_frame(State=#state{opts=Opts, streams=Streams}, StreamID, Req) ->
try cowboy_stream:init(StreamID, Req, Opts) of
{Commands, StreamState} ->
commands(State#state{
streams=Streams#{StreamID => #stream{state=StreamState}}},
StreamID, Commands)
catch Class:Exception ->
cowboy:log(cowboy_stream:make_error_log(init,
[StreamID, Req, Opts],
Class, Exception, erlang:get_stacktrace()), Opts),
reset_stream(State, StreamID, {internal_error, {Class, Exception},
'Unhandled exception in cowboy_stream:init/3.'})
end.
early_error(State0=#state{ref=Ref, opts=Opts, peer=Peer},
StreamID, _IsFin, Headers, #{method := Method},
StatusCode0, HumanReadable) ->
%% We automatically terminate the stream but it is not an error
%% per se (at least not in the first implementation).
Reason = {stream_error, no_error, HumanReadable},
%% The partial Req is minimal for now. We only have one case
%% where it can be called (when a method is completely disabled).
%% @todo Fill in the other elements.
PartialReq = #{
ref => Ref,
peer => Peer,
method => Method,
headers => headers_to_map(Headers, #{})
},
Resp = {response, StatusCode0, RespHeaders0=#{<<"content-length">> => <<"0">>}, <<>>},
try cowboy_stream:early_error(StreamID, Reason, PartialReq, Resp, Opts) of
{response, StatusCode, RespHeaders, RespBody} ->
send_response(State0, StreamID, StatusCode, RespHeaders, RespBody)
catch Class:Exception ->
cowboy:log(cowboy_stream:make_error_log(early_error,
[StreamID, Reason, PartialReq, Resp, Opts],
Class, Exception, erlang:get_stacktrace()), Opts),
%% We still need to send an error response, so send what we initially
%% wanted to send. It's better than nothing.
send_headers(State0, StreamID, fin, StatusCode0, RespHeaders0)
end.
rst_stream_frame(State=#state{streams=Streams0, children=Children0}, StreamID, Reason) ->
case maps:take(StreamID, Streams0) of
{#stream{state=StreamState}, Streams} ->
terminate_stream_handler(State, StreamID, Reason, StreamState),
Children = cowboy_children:shutdown(Children0, StreamID),
State#state{streams=Streams, children=Children};
error ->
State
end.
ignored_frame(State=#state{http2_machine=HTTP2Machine0}) ->
case cow_http2_machine:ignored_frame(HTTP2Machine0) of
{ok, HTTP2Machine} ->
State#state{http2_machine=HTTP2Machine};
{error, Error={connection_error, _, _}, HTTP2Machine} ->
terminate(State#state{http2_machine=HTTP2Machine}, Error)
end.
%% HTTP/2 timeouts.
timeout(State=#state{http2_machine=HTTP2Machine0}, Name, TRef) ->
case cow_http2_machine:timeout(Name, TRef, HTTP2Machine0) of
{ok, HTTP2Machine} ->
State#state{http2_machine=HTTP2Machine};
{error, Error={connection_error, _, _}, HTTP2Machine} ->
terminate(State#state{http2_machine=HTTP2Machine}, Error)
end.
%% Erlang messages.
down(State=#state{opts=Opts, children=Children0}, Pid, Msg) ->
case cowboy_children:down(Children0, Pid) of
%% The stream was terminated already.
{ok, undefined, Children} ->
State#state{children=Children};
%% The stream is still running.
{ok, StreamID, Children} ->
info(State#state{children=Children}, StreamID, Msg);
%% The process was unknown.
error ->
cowboy:log(warning, "Received EXIT signal ~p for unknown process ~p.~n",
[Msg, Pid], Opts),
State
end.
info(State=#state{opts=Opts, streams=Streams}, StreamID, Msg) ->
case Streams of
#{StreamID := Stream=#stream{state=StreamState0}} ->
try cowboy_stream:info(StreamID, Msg, StreamState0) of
{Commands, StreamState} ->
commands(State#state{streams=Streams#{StreamID => Stream#stream{state=StreamState}}},
StreamID, Commands)
catch Class:Exception ->
cowboy:log(cowboy_stream:make_error_log(info,
[StreamID, Msg, StreamState0],
Class, Exception, erlang:get_stacktrace()), Opts),
reset_stream(State, StreamID, {internal_error, {Class, Exception},
'Unhandled exception in cowboy_stream:info/3.'})
end;
_ ->
cowboy:log(warning, "Received message ~p for unknown or terminated stream ~p.",
[Msg, StreamID], Opts),
State
end.
%% Stream handler commands.
%%
%% @todo Kill the stream if it tries to send a response, headers,
%% data or push promise when the stream is closed or half-closed.
commands(State, _, []) ->
State;
%% Error responses are sent only if a response wasn't sent already.
commands(State=#state{http2_machine=HTTP2Machine}, StreamID,
[{error_response, StatusCode, Headers, Body}|Tail]) ->
case cow_http2_machine:get_stream_local_state(StreamID, HTTP2Machine) of
{ok, idle, _} ->
commands(State, StreamID, [{response, StatusCode, Headers, Body}|Tail]);
_ ->
commands(State, StreamID, Tail)
end;
%% Send an informational response.
commands(State0, StreamID, [{inform, StatusCode, Headers}|Tail]) ->
State = send_headers(State0, StreamID, idle, StatusCode, Headers),
commands(State, StreamID, Tail);
%% Send response headers.
commands(State0, StreamID, [{response, StatusCode, Headers, Body}|Tail]) ->
State = send_response(State0, StreamID, StatusCode, Headers, Body),
commands(State, StreamID, Tail);
%% Send response headers.
commands(State0, StreamID, [{headers, StatusCode, Headers}|Tail]) ->
State = send_headers(State0, StreamID, nofin, StatusCode, Headers),
commands(State, StreamID, Tail);
%% Send a response body chunk.
commands(State0, StreamID, [{data, IsFin, Data}|Tail]) ->
State = maybe_send_data(State0, StreamID, IsFin, Data),
commands(State, StreamID, Tail);
%% Send trailers.
commands(State0, StreamID, [{trailers, Trailers}|Tail]) ->
State = maybe_send_data(State0, StreamID, fin, {trailers, maps:to_list(Trailers)}),
commands(State, StreamID, Tail);
%% Send a push promise.
%%
%% @todo Responses sent as a result of a push_promise request
%% must not send push_promise frames themselves.
%%
%% @todo We should not send push_promise frames when we are
%% in the closing http2_status.
commands(State0=#state{socket=Socket, transport=Transport, http2_machine=HTTP2Machine0},
StreamID, [{push, Method, Scheme, Host, Port, Path, Qs, Headers0}|Tail]) ->
Authority = case {Scheme, Port} of
{<<"http">>, 80} -> Host;
{<<"https">>, 443} -> Host;
_ -> iolist_to_binary([Host, $:, integer_to_binary(Port)])
end,
PathWithQs = iolist_to_binary(case Qs of
<<>> -> Path;
_ -> [Path, $?, Qs]
end),
PseudoHeaders = #{
method => Method,
scheme => Scheme,
authority => Authority,
path => PathWithQs
},
%% We need to make sure the header value is binary before we can
%% create the Req object, as it expects them to be flat.
Headers = maps:to_list(maps:map(fun(_, V) -> iolist_to_binary(V) end, Headers0)),
State = case cow_http2_machine:prepare_push_promise(StreamID, HTTP2Machine0,
PseudoHeaders, Headers) of
{ok, PromisedStreamID, HeaderBlock, HTTP2Machine} ->
Transport:send(Socket, cow_http2:push_promise(
StreamID, PromisedStreamID, HeaderBlock)),
headers_frame(State0#state{http2_machine=HTTP2Machine},
PromisedStreamID, fin, Headers, PseudoHeaders, 0);
{error, no_push} ->
State0
end,
commands(State, StreamID, Tail);
%% Read the request body.
commands(State0=#state{flow=Flow, streams=Streams}, StreamID, [{flow, Size}|Tail]) ->
#{StreamID := Stream=#stream{flow=StreamFlow}} = Streams,
State = update_window(State0#state{flow=Flow + Size,
streams=Streams#{StreamID => Stream#stream{flow=StreamFlow + Size}}},
StreamID),
commands(State, StreamID, Tail);
%% Supervise a child process.
commands(State=#state{children=Children}, StreamID, [{spawn, Pid, Shutdown}|Tail]) ->
commands(State#state{children=cowboy_children:up(Children, Pid, StreamID, Shutdown)},
StreamID, Tail);
%% Error handling.
commands(State, StreamID, [Error = {internal_error, _, _}|_Tail]) ->
%% @todo Do we want to run the commands after an internal_error?
%% @todo Do we even allow commands after?
%% @todo Only reset when the stream still exists.
reset_stream(State, StreamID, Error);
%% Upgrade to HTTP/2. This is triggered by cowboy_http2 itself.
commands(State=#state{socket=Socket, transport=Transport, http2_status=upgrade},
StreamID, [{switch_protocol, Headers, ?MODULE, _}|Tail]) ->
%% @todo This 101 response needs to be passed through stream handlers.
Transport:send(Socket, cow_http:response(101, 'HTTP/1.1', maps:to_list(Headers))),
commands(State, StreamID, Tail);
%% Use a different protocol within the stream (CONNECT :protocol).
%% @todo Make sure we error out when the feature is disabled.
commands(State0, StreamID, [{switch_protocol, Headers, _Mod, _ModState}|Tail]) ->
State = info(State0, StreamID, {headers, 200, Headers}),
commands(State, StreamID, Tail);
%% Set options dynamically.
commands(State, StreamID, [{set_options, _Opts}|Tail]) ->
commands(State, StreamID, Tail);
commands(State, StreamID, [stop|_Tail]) ->
%% @todo Do we want to run the commands after a stop?
%% @todo Do we even allow commands after?
stop_stream(State, StreamID);
%% Log event.
commands(State=#state{opts=Opts}, StreamID, [Log={log, _, _, _}|Tail]) ->
cowboy:log(Log, Opts),
commands(State, StreamID, Tail).
%% Tentatively update the window after the flow was updated.
update_window(State=#state{socket=Socket, transport=Transport,
http2_machine=HTTP2Machine0, flow=Flow, streams=Streams}, StreamID) ->
#{StreamID := #stream{flow=StreamFlow}} = Streams,
{Data1, HTTP2Machine2} = case cow_http2_machine:ensure_window(Flow, HTTP2Machine0) of
ok -> {<<>>, HTTP2Machine0};
{ok, Increment1, HTTP2Machine1} -> {cow_http2:window_update(Increment1), HTTP2Machine1}
end,
{Data2, HTTP2Machine} = case cow_http2_machine:ensure_window(StreamID, StreamFlow, HTTP2Machine2) of
ok -> {<<>>, HTTP2Machine2};
{ok, Increment2, HTTP2Machine3} -> {cow_http2:window_update(StreamID, Increment2), HTTP2Machine3}
end,
case {Data1, Data2} of
{<<>>, <<>>} -> ok;
_ -> Transport:send(Socket, [Data1, Data2])
end,
State#state{http2_machine=HTTP2Machine}.
%% Send the response, trailers or data.
send_response(State0, StreamID, StatusCode, Headers, Body) ->
Size = case Body of
{sendfile, _, Bytes, _} -> Bytes;
_ -> iolist_size(Body)
end,
case Size of
0 ->
State = send_headers(State0, StreamID, fin, StatusCode, Headers),
maybe_terminate_stream(State, StreamID, fin);
_ ->
State = send_headers(State0, StreamID, nofin, StatusCode, Headers),
maybe_send_data(State, StreamID, fin, Body)
end.
send_headers(State=#state{socket=Socket, transport=Transport,
http2_machine=HTTP2Machine0}, StreamID, IsFin0, StatusCode, Headers) ->
{ok, IsFin, HeaderBlock, HTTP2Machine}
= cow_http2_machine:prepare_headers(StreamID, HTTP2Machine0, IsFin0,
#{status => cow_http:status_to_integer(StatusCode)},
headers_to_list(Headers)),
Transport:send(Socket, cow_http2:headers(StreamID, IsFin, HeaderBlock)),
State#state{http2_machine=HTTP2Machine}.
%% The set-cookie header is special; we can only send one cookie per header.
headers_to_list(Headers0=#{<<"set-cookie">> := SetCookies}) ->
Headers = maps:to_list(maps:remove(<<"set-cookie">>, Headers0)),
Headers ++ [{<<"set-cookie">>, Value} || Value <- SetCookies];
headers_to_list(Headers) ->
maps:to_list(Headers).
maybe_send_data(State0=#state{http2_machine=HTTP2Machine0}, StreamID, IsFin, Data0) ->
Data = case is_tuple(Data0) of
false -> {data, Data0};
true -> Data0
end,
case cow_http2_machine:send_or_queue_data(StreamID, HTTP2Machine0, IsFin, Data) of
{ok, HTTP2Machine} ->
maybe_send_data_alarm(State0#state{http2_machine=HTTP2Machine}, HTTP2Machine0, StreamID);
{send, SendData, HTTP2Machine} ->
State = #state{http2_status=Status, streams=Streams}
= send_data(State0#state{http2_machine=HTTP2Machine}, SendData),
%% Terminate the connection if we are closing and all streams have completed.
if
Status =:= closing, Streams =:= #{} ->
terminate(State, {stop, normal, 'The connection is going away.'});
true ->
maybe_send_data_alarm(State, HTTP2Machine0, StreamID)
end
end.
send_data(State, []) ->
State;
send_data(State0, [{StreamID, IsFin, SendData}|Tail]) ->
State = send_data(State0, StreamID, IsFin, SendData),
send_data(State, Tail).
send_data(State0, StreamID, IsFin, [Data]) ->
State = send_data_frame(State0, StreamID, IsFin, Data),
maybe_terminate_stream(State, StreamID, IsFin);
send_data(State0, StreamID, IsFin, [Data|Tail]) ->
State = send_data_frame(State0, StreamID, nofin, Data),
send_data(State, StreamID, IsFin, Tail).
send_data_frame(State=#state{socket=Socket, transport=Transport},
StreamID, IsFin, {data, Data}) ->
Transport:send(Socket, cow_http2:data(StreamID, IsFin, Data)),
State;
send_data_frame(State=#state{socket=Socket, transport=Transport, opts=Opts},
StreamID, IsFin, {sendfile, Offset, Bytes, Path}) ->
Transport:send(Socket, cow_http2:data_header(StreamID, IsFin, Bytes)),
%% When sendfile is disabled we explicitly use the fallback.
_ = case maps:get(sendfile, Opts, true) of
true -> Transport:sendfile(Socket, Path, Offset, Bytes);
false -> ranch_transport:sendfile(Transport, Socket, Path, Offset, Bytes, [])
end,
State;
%% The stream is terminated in cow_http2_machine:prepare_trailers.
send_data_frame(State=#state{socket=Socket, transport=Transport,
http2_machine=HTTP2Machine0}, StreamID, nofin, {trailers, Trailers}) ->
{ok, HeaderBlock, HTTP2Machine}
= cow_http2_machine:prepare_trailers(StreamID, HTTP2Machine0, Trailers),
Transport:send(Socket, cow_http2:headers(StreamID, fin, HeaderBlock)),
State#state{http2_machine=HTTP2Machine}.
%% After we have sent or queued data we may need to set or clear an alarm.
%% We do this by comparing the HTTP2Machine buffer state before/after for
%% the relevant streams.
maybe_send_data_alarm(State=#state{opts=Opts, http2_machine=HTTP2Machine}, HTTP2Machine0, StreamID) ->
ConnBufferSizeBefore = cow_http2_machine:get_connection_local_buffer_size(HTTP2Machine0),
ConnBufferSizeAfter = cow_http2_machine:get_connection_local_buffer_size(HTTP2Machine),
{ok, StreamBufferSizeBefore} = cow_http2_machine:get_stream_local_buffer_size(StreamID, HTTP2Machine0),
%% When the stream ends up closed after it finished sending data,
%% we do not want to trigger an alarm. We act as if the buffer
%% size did not change.
StreamBufferSizeAfter = case cow_http2_machine:get_stream_local_buffer_size(StreamID, HTTP2Machine) of
{ok, BSA} -> BSA;
{error, closed} -> StreamBufferSizeBefore
end,
MaxConnBufferSize = maps:get(max_connection_buffer_size, Opts, 16000000),
MaxStreamBufferSize = maps:get(max_stream_buffer_size, Opts, 8000000),
%% I do not want to document these internal events yet. I am not yet
%% convinced it should be {alarm, Name, on|off} and not {internal_event, E}
%% or something else entirely. Though alarms are probably right.
if
ConnBufferSizeBefore >= MaxConnBufferSize, ConnBufferSizeAfter < MaxConnBufferSize ->
connection_alarm(State, connection_buffer_full, off);
ConnBufferSizeBefore < MaxConnBufferSize, ConnBufferSizeAfter >= MaxConnBufferSize ->
connection_alarm(State, connection_buffer_full, on);
StreamBufferSizeBefore >= MaxStreamBufferSize, StreamBufferSizeAfter < MaxStreamBufferSize ->
stream_alarm(State, StreamID, stream_buffer_full, off);
StreamBufferSizeBefore < MaxStreamBufferSize, StreamBufferSizeAfter >= MaxStreamBufferSize ->
stream_alarm(State, StreamID, stream_buffer_full, on);
true ->
State
end.
connection_alarm(State0=#state{streams=Streams}, Name, Value) ->
lists:foldl(fun(StreamID, State) ->
stream_alarm(State, StreamID, Name, Value)
end, State0, maps:keys(Streams)).
stream_alarm(State, StreamID, Name, Value) ->
info(State, StreamID, {alarm, Name, Value}).
%% Terminate a stream or the connection.
%% We may have to cancel streams even if we receive multiple
%% GOAWAY frames as the LastStreamID value may be lower than
%% the one previously received.
goaway(State0=#state{socket=Socket, transport=Transport, http2_machine=HTTP2Machine,
http2_status=Status, streams=Streams0}, {goaway, LastStreamID, Reason, _})
when Status =:= connected; Status =:= closing ->
Streams = goaway_streams(State0, maps:to_list(Streams0), LastStreamID,
{stop, {goaway, Reason}, 'The connection is going away.'}, []),
State = State0#state{streams=maps:from_list(Streams)},
case Status of
connected ->
Transport:send(Socket, cow_http2:goaway(
cow_http2_machine:get_last_streamid(HTTP2Machine),
no_error, <<>>)),
State#state{http2_status=closing};
_ ->
State
end;
%% We terminate the connection immediately if it hasn't fully been initialized.
goaway(State, {goaway, _, Reason, _}) ->
terminate(State, {stop, {goaway, Reason}, 'The connection is going away.'}).
%% Cancel client-initiated streams that are above LastStreamID.
goaway_streams(_, [], _, _, Acc) ->
Acc;
goaway_streams(State, [{StreamID, #stream{state=StreamState}}|Tail], LastStreamID, Reason, Acc)
when StreamID > LastStreamID, (StreamID rem 2) =:= 0 ->
terminate_stream_handler(State, StreamID, Reason, StreamState),
goaway_streams(State, Tail, LastStreamID, Reason, Acc);
goaway_streams(State, [Stream|Tail], LastStreamID, Reason, Acc) ->
goaway_streams(State, Tail, LastStreamID, Reason, [Stream|Acc]).
-spec terminate(#state{}, _) -> no_return().
terminate(undefined, Reason) ->
exit({shutdown, Reason});
terminate(State=#state{socket=Socket, transport=Transport, http2_status=Status,
http2_machine=HTTP2Machine, streams=Streams, children=Children}, Reason)
when Status =:= connected; Status =:= closing ->
%% @todo We might want to optionally send the Reason value
%% as debug data in the GOAWAY frame here. Perhaps more.
case Status of
connected ->
Transport:send(Socket, cow_http2:goaway(
cow_http2_machine:get_last_streamid(HTTP2Machine),
terminate_reason(Reason), <<>>));
%% We already sent the GOAWAY frame.
closing ->
ok
end,
terminate_all_streams(State, maps:to_list(Streams), Reason),
cowboy_children:terminate(Children),
Transport:close(Socket),
exit({shutdown, Reason});
terminate(#state{socket=Socket, transport=Transport}, Reason) ->
Transport:close(Socket),
exit({shutdown, Reason}).
terminate_reason({connection_error, Reason, _}) -> Reason;
terminate_reason({stop, _, _}) -> no_error;
terminate_reason({socket_error, _, _}) -> internal_error;
terminate_reason({internal_error, _, _}) -> internal_error.
terminate_all_streams(_, [], _) ->
ok;
terminate_all_streams(State, [{StreamID, #stream{state=StreamState}}|Tail], Reason) ->
terminate_stream_handler(State, StreamID, Reason, StreamState),
terminate_all_streams(State, Tail, Reason).
%% @todo Don't send an RST_STREAM if one was already sent.
reset_stream(State0=#state{socket=Socket, transport=Transport,
http2_machine=HTTP2Machine0}, StreamID, Error) ->
Reason = case Error of
{internal_error, _, _} -> internal_error;
{stream_error, Reason0, _} -> Reason0
end,
Transport:send(Socket, cow_http2:rst_stream(StreamID, Reason)),
State1 = case cow_http2_machine:reset_stream(StreamID, HTTP2Machine0) of
{ok, HTTP2Machine} ->
terminate_stream(State0#state{http2_machine=HTTP2Machine}, StreamID, Error);
{error, not_found} ->
terminate_stream(State0, StreamID, Error)
end,
case reset_rate(State1) of
{ok, State} ->
State;
error ->
terminate(State1, {connection_error, enhance_your_calm,
'Stream reset rate larger than configuration allows. Flood? (CVE-2019-9514)'})
end.
reset_rate(State0=#state{opts=Opts, reset_rate_num=Num0, reset_rate_time=Time}) ->
case Num0 - 1 of
0 ->
CurrentTime = erlang:monotonic_time(millisecond),
if
CurrentTime < Time ->
error;
true ->
%% When the option has a period of infinity we cannot reach this clause.
{Num, Period} = maps:get(max_reset_stream_rate, Opts, {10, 10000}),
{ok, State0#state{reset_rate_num=Num, reset_rate_time=CurrentTime + Period}}
end;
Num ->
{ok, State0#state{reset_rate_num=Num}}
end.
stop_stream(State=#state{http2_machine=HTTP2Machine}, StreamID) ->
case cow_http2_machine:get_stream_local_state(StreamID, HTTP2Machine) of
%% When the stream terminates normally (without sending RST_STREAM)
%% and no response was sent, we need to send a proper response back to the client.
%% We delay the termination of the stream until the response is fully sent.
{ok, idle, _} ->
info(stopping(State, StreamID), StreamID, {response, 204, #{}, <<>>});
%% When a response was sent but not terminated, we need to close the stream.
%% We delay the termination of the stream until the response is fully sent.
{ok, nofin, fin} ->
stopping(State, StreamID);
%% We only send a final DATA frame if there isn't one queued yet.
{ok, nofin, _} ->
info(stopping(State, StreamID), StreamID, {data, fin, <<>>});
%% When a response was sent fully we can terminate the stream,
%% regardless of the stream being in half-closed or closed state.
_ ->
terminate_stream(State, StreamID)
end.
stopping(State=#state{streams=Streams}, StreamID) ->
#{StreamID := Stream} = Streams,
State#state{streams=Streams#{StreamID => Stream#stream{status=stopping}}}.
%% If we finished sending data and the stream is stopping, terminate it.
maybe_terminate_stream(State=#state{streams=Streams}, StreamID, fin) ->
case Streams of
#{StreamID := #stream{status=stopping}} ->
terminate_stream(State, StreamID);
_ ->
State
end;
maybe_terminate_stream(State, _, _) ->
State.
%% When the stream stops normally without reading the request
%% body fully we need to tell the client to stop sending it.
%% We do this by sending an RST_STREAM with reason NO_ERROR. (RFC7540 8.1.0)
terminate_stream(State0=#state{socket=Socket, transport=Transport,
http2_machine=HTTP2Machine0}, StreamID) ->
State = case cow_http2_machine:get_stream_local_state(StreamID, HTTP2Machine0) of
{ok, fin, _} ->
Transport:send(Socket, cow_http2:rst_stream(StreamID, no_error)),
{ok, HTTP2Machine} = cow_http2_machine:reset_stream(StreamID, HTTP2Machine0),
State0#state{http2_machine=HTTP2Machine};
{error, closed} ->
State0
end,
terminate_stream(State, StreamID, normal).
%% We remove the stream flow from the connection flow. Any further
%% data received for this stream is therefore fully contained within
%% the extra window we allocated for this stream.
terminate_stream(State=#state{flow=Flow, streams=Streams0, children=Children0}, StreamID, Reason) ->
case maps:take(StreamID, Streams0) of
{#stream{flow=StreamFlow, state=StreamState}, Streams} ->
terminate_stream_handler(State, StreamID, Reason, StreamState),
Children = cowboy_children:shutdown(Children0, StreamID),
State#state{flow=Flow - StreamFlow, streams=Streams, children=Children};
error ->
State
end.
terminate_stream_handler(#state{opts=Opts}, StreamID, Reason, StreamState) ->
try
cowboy_stream:terminate(StreamID, Reason, StreamState)
catch Class:Exception ->
cowboy:log(cowboy_stream:make_error_log(terminate,
[StreamID, Reason, StreamState],
Class, Exception, erlang:get_stacktrace()), Opts)
end.
%% System callbacks.
-spec system_continue(_, _, {#state{}, binary()}) -> ok.
system_continue(_, _, {State, Buffer}) ->
loop(State, Buffer).
-spec system_terminate(any(), _, _, {#state{}, binary()}) -> no_return().
system_terminate(Reason, _, _, {State, _}) ->
%% @todo Graceful shutdown here as well?
terminate(State, {stop, {exit, Reason}, 'sys:terminate/2,3 was called.'}).
-spec system_code_change(Misc, _, _, _) -> {ok, Misc} when Misc::{#state{}, binary()}.
system_code_change(Misc, _, _, _) ->
{ok, Misc}.
