%%% @doc Per-tunnel server session for classic CONNECT-TCP over
%%% HTTP/1.1 (RFC 9110 ยง9.3.6).
%%%
%%% Spawned by `masque_h1_server' after a `CONNECT' method + valid
%%% authority-form request-target passes validation. This session
%%% takes the raw TLS socket over from the h1 state machine via
%%% `h1:accept_connect/3' (writes the 200 Connection Established
%%% response atomically, no response-body framing), then bridges
%%% bytes through the configured `tcp_handler' (default
%%% `masque_tcp_proxy_handler'), which owns the outbound target
%%% socket.
%%%
%%% Handler contract identical to `masque_tcp_server_session':
%%% `init/2' opens the target, `handle_data/2' forwards
%%% client-to-target, `handle_info/2' returns `{send_data, Bytes}'
%%% actions for target-to-client. The only difference on this path
%%% is the proxy-side wire (raw `ssl:send/2', no capsules, no
%%% Extended CONNECT).
-module(masque_tcp_h1_server_session).
-behaviour(gen_server).
-export([start_link/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-record(state, {
transport :: gen_tcp | ssl,
socket :: ssl:sslsocket() | gen_tcp:socket(),
handler :: module(),
h_state :: term(),
req :: map(),
start_time :: integer() | undefined,
idle_ms :: non_neg_integer() | infinity,
idle_ref :: reference() | undefined
}).
%%====================================================================
%% API
%%====================================================================
-spec start_link(map()) -> {ok, pid()} | ignore | {error, term()}.
start_link(Args) ->
gen_server:start_link(?MODULE, Args, []).
%%====================================================================
%% gen_server
%%====================================================================
init(#{conn := Conn, stream_id := StreamId,
handler := Handler, handler_opts := HOpts, req := Req}) ->
process_flag(trap_exit, true),
IdleMs = maps:get(idle_timeout_ms, HOpts, 300000),
case init_handler(Handler, Req, HOpts) of
{ok, HState, InitActions} ->
case h1:accept_connect(Conn, StreamId, []) of
{ok, Transport, Socket, Buffer} ->
State0 = arm_idle(#state{
transport = Transport,
socket = Socket,
handler = Handler,
h_state = HState,
req = Req,
start_time = erlang:monotonic_time(millisecond),
idle_ms = IdleMs
}),
case apply_init_actions(InitActions, State0) of
{ok, State1} ->
%% Any bytes read past the CRLF blank line
%% belong to the tunnel - feed them to the
%% handler before arming active-once. If
%% the handler crashes on that first chunk,
%% close the socket before stopping so the
%% raw TLS session does not leak.
case seed_handler(Buffer, State1) of
{stop, Reason} ->
_ = safe_close_socket(State1),
{stop, Reason};
State2 ->
_ = arm_once(State2),
{ok, State2}
end;
{stop, Reason, _S} ->
_ = safe_close_socket(State0),
{stop, Reason}
end;
{error, Reason} ->
try_callback(Handler, terminate,
[{accept_connect, Reason}, HState]),
{stop, {accept_connect, Reason}}
end;
{stop, Reason} ->
%% Target resolution / policy denied this request. The
%% listener already checked `accept/1' before spawning us;
%% reject here surfaces via `{stop, _}' and the listener
%% treats it as a 502.
{stop, Reason}
end.
handle_call(_Req, _From, S) ->
{reply, {error, unknown_call}, S}.
handle_cast(_Msg, S) ->
{noreply, S}.
handle_info({ssl, Sock, Bytes}, #state{socket = Sock} = S) ->
handle_proxy_bytes(Bytes, arm_idle(S));
handle_info({tcp, Sock, Bytes}, #state{socket = Sock} = S) ->
handle_proxy_bytes(Bytes, arm_idle(S));
handle_info({timeout, Ref, idle},
#state{idle_ref = Ref} = S) ->
{stop, idle_timeout, S};
handle_info({ssl_closed, Sock}, #state{socket = Sock} = S) ->
handle_proxy_eof(S);
handle_info({tcp_closed, Sock}, #state{socket = Sock} = S) ->
handle_proxy_eof(S);
handle_info({ssl_error, Sock, Reason}, #state{socket = Sock} = S) ->
{stop, {ssl_error, Reason}, S};
handle_info({tcp_error, Sock, Reason}, #state{socket = Sock} = S) ->
{stop, {tcp_error, Reason}, S};
handle_info({'EXIT', _Pid, _Reason}, S) ->
{noreply, S};
handle_info(Msg, S) ->
dispatch(handle_info, [Msg], S).
terminate(Reason, #state{handler = Handler, h_state = HState,
start_time = Start} = S) ->
_ = cancel_idle(S),
_ = safe_close_socket(S),
try_callback(Handler, terminate, [Reason, HState]),
_ = emit_tunnel_closed(Start),
ok.
code_change(_OldVsn, S, _Extra) ->
{ok, S}.
emit_tunnel_closed(undefined) -> ok;
emit_tunnel_closed(T) ->
Duration = erlang:monotonic_time(millisecond) - T,
masque_metrics:tunnel_closed(Duration,
#{protocol => tcp, transport => h1}).
%%====================================================================
%% Proxy-side data path
%%====================================================================
handle_proxy_bytes(Bytes, S) ->
case dispatch(handle_data, [Bytes], S) of
{noreply, S2} ->
_ = arm_once(S2),
{noreply, S2};
Other ->
Other
end.
handle_proxy_eof(#state{handler = Handler} = S) ->
case exported(Handler, handle_eof, 1) of
true ->
case dispatch(handle_eof, [], S) of
{noreply, S2} -> {stop, normal, S2};
{stop, _, _} = Stop -> Stop
end;
false ->
{stop, normal, S}
end.
seed_handler(<<>>, S) ->
S;
seed_handler(Bytes, S) ->
case dispatch(handle_data, [Bytes], S) of
{noreply, S2} -> S2;
{stop, Reason, _S2} -> {stop, Reason}
end.
%%====================================================================
%% Handler dispatch (mirrors masque_tcp_server_session)
%%====================================================================
init_handler(Handler, Req, HOpts) ->
case exported(Handler, init, 2) of
true ->
case safe_apply(Handler, init, [Req, HOpts]) of
{ok, HState} -> {ok, HState, []};
{ok, HState, Actions} -> {ok, HState, Actions};
{stop, Reason} -> {stop, Reason};
Other -> {stop, {bad_init, Other}}
end;
false ->
{ok, undefined, []}
end.
dispatch(CB, Extra, #state{handler = Handler, h_state = HS} = S) ->
case exported(Handler, CB, length(Extra) + 1) of
true ->
case safe_apply(Handler, CB, Extra ++ [HS]) of
{ok, HS2} -> {noreply, S#state{h_state = HS2}};
{ok, HS2, Actions} -> apply_actions_noreply(
Actions, S#state{h_state = HS2});
{stop, Reason, HS2} -> {stop, Reason,
S#state{h_state = HS2}};
_ -> {noreply, S}
end;
false ->
{noreply, S}
end.
exported(Mod, Fun, Arity) ->
_ = code:ensure_loaded(Mod),
erlang:function_exported(Mod, Fun, Arity).
apply_init_actions(Actions, State) ->
case do_actions(Actions, State) of
{ok, S2} -> {ok, S2};
{stop, Reason, S2} -> {stop, Reason, S2}
end.
apply_actions_noreply(Actions, State) ->
case do_actions(Actions, State) of
{ok, S2} -> {noreply, S2};
{stop, Reason, S2} -> {stop, Reason, S2}
end.
do_actions([], S) ->
{ok, S};
do_actions([{send_data, Bytes} | Rest], S) ->
_ = proxy_send(S, Bytes),
do_actions(Rest, S);
do_actions([{send_data, Bytes, _Fin} | Rest], S) ->
_ = proxy_send(S, Bytes),
do_actions(Rest, S);
do_actions([close_session | _Rest], S) ->
{stop, normal, S};
do_actions([_Unknown | Rest], S) ->
do_actions(Rest, S).
proxy_send(#state{transport = ssl, socket = Sock}, Bytes) ->
ssl:send(Sock, Bytes);
proxy_send(#state{transport = gen_tcp, socket = Sock}, Bytes) ->
gen_tcp:send(Sock, Bytes).
%%====================================================================
%% Socket helpers
%%====================================================================
arm_once(#state{transport = ssl, socket = Sock}) ->
ssl:setopts(Sock, [{active, once}, {mode, binary}]);
arm_once(#state{transport = gen_tcp, socket = Sock}) ->
inet:setopts(Sock, [{active, once}, {mode, binary}]).
safe_close_socket(State) ->
try close_socket(State) catch _:_ -> ok end.
close_socket(#state{transport = ssl, socket = S}) -> ssl:close(S);
close_socket(#state{transport = gen_tcp, socket = S}) -> gen_tcp:close(S).
%%====================================================================
%% Misc
%%====================================================================
safe_apply(M, F, A) ->
try apply(M, F, A)
catch
Class:Reason:Stack ->
error_logger:error_msg(
"masque tcp-h1 handler ~p:~p/~p failed: ~p:~p~n~p~n",
[M, F, length(A), Class, Reason, Stack]),
{stop, {handler_crash, Reason}}
end.
try_callback(Mod, Fun, Args) ->
Arity = length(Args),
case erlang:function_exported(Mod, Fun, Arity) of
true -> (try apply(Mod, Fun, Args) catch _:_ -> ok end);
false -> ok
end.
%%====================================================================
%% Idle timer
%%====================================================================
arm_idle(#state{idle_ms = infinity} = S) -> S;
arm_idle(#state{idle_ms = 0} = S) -> S;
arm_idle(#state{idle_ref = OldRef, idle_ms = Ms} = S) ->
case OldRef of
undefined -> ok;
_ -> _ = erlang:cancel_timer(OldRef), ok
end,
Ref = erlang:start_timer(Ms, self(), idle),
S#state{idle_ref = Ref}.
cancel_idle(#state{idle_ref = undefined}) -> ok;
cancel_idle(#state{idle_ref = Ref}) ->
_ = erlang:cancel_timer(Ref),
ok.