%%% @doc MASQUE CONNECT-UDP listener over HTTP/1.1.
%%%
%%% Wraps `h1:start_server/3' with a request handler that validates
%%% the RFC 9298 Upgrade envelope (`GET' + `Upgrade: connect-udp' +
%%% `Capsule-Protocol: ?1'), matches the path against the configured
%%% URI template, and spawns a per-tunnel `masque_h1_server_session'
%%% on acceptance. The session itself calls `h1:accept_upgrade/3' so
%%% socket ownership lands on the session gen_server.
%%%
%%% No per-connection tunnel accounting: h1 Upgrade inherently tops
%%% out at one tunnel per TCP/TLS connection (the state machine
%%% shuts down and hands off the socket on 101).
%%%
%%% Handles CONNECT-UDP, CONNECT-IP, and classic CONNECT-TCP (the
%%% RFC 9110 §9.3.6 tunnel). The first two use HTTP Upgrade + RFC 9297
%%% capsules; CONNECT-TCP uses the classic `CONNECT host:port HTTP/1.1'
%%% method and becomes a raw byte pipe after the 200 response.
-module(masque_h1_server).
-export([
start_listener/2,
stop_listener/1,
h1_handlers/1
]).
-include("masque.hrl").
-include("masque_ip.hrl").
-type listener_name() :: atom().
-type listener_opts() :: map().
-export_type([listener_name/0, listener_opts/0]).
%%====================================================================
%% API
%%====================================================================
-spec start_listener(listener_name(), listener_opts()) ->
{ok, h1:server_ref()} | {error, term()}.
start_listener(Name, Opts0) when is_atom(Name), is_map(Opts0) ->
persistent_term:erase({masque_drain, Name}),
Opts = defaults(Opts0),
Port = maps:get(port, Opts),
#{handler := Handler} = h1_handlers(Opts#{drain_key => Name}),
ServerOpts0 = #{
transport => ssl,
cert => maps:get(cert, Opts),
key => maps:get(key, Opts),
handler => Handler
},
ServerOpts = maybe_add(acceptors, Opts, ServerOpts0),
case h1:start_server(Name, Port, ServerOpts) of
{ok, Ref} ->
persistent_term:put({masque_h1_ref, Name}, Ref),
persistent_term:put({masque_h1_name, Ref}, Name),
{ok, Ref};
Error -> Error
end.
-spec stop_listener(h1:server_ref() | listener_name()) -> ok | {error, term()}.
stop_listener({_, _, _} = Ref) ->
case persistent_term:get({masque_h1_name, Ref}, undefined) of
undefined -> ok;
Name ->
persistent_term:erase({masque_drain, Name}),
persistent_term:erase({masque_h1_ref, Name}),
persistent_term:erase({masque_h1_name, Ref})
end,
h1:stop_server(Ref);
stop_listener(Name) when is_atom(Name) ->
case persistent_term:get({masque_h1_ref, Name}, undefined) of
undefined -> {error, {no_ref_for_name, Name}};
Ref -> stop_listener(Ref)
end.
-spec h1_handlers(map()) -> #{handler := module() | fun()}.
h1_handlers(Opts0) ->
Opts = defaults(Opts0),
Dispatch = build_dispatch(Opts),
#{handler => make_dispatch_fun(Dispatch)}.
%%====================================================================
%% Internal
%%====================================================================
defaults(Opts) ->
D = #{
uri_template => ?MASQUE_DEFAULT_URI_TEMPLATE,
ip_uri_template => ?MASQUE_DEFAULT_IP_URI_PATH_PATTERN,
handler => masque_udp_proxy_handler,
ip_handler => masque_ip_proxy_handler,
tcp_handler => masque_tcp_proxy_handler,
bind_handler => masque_udp_bind_proxy_handler,
accept_bind => false
},
maps:merge(D, Opts).
maybe_add(Key, From, Into) ->
case maps:find(Key, From) of
{ok, V} -> Into#{Key => V};
error -> Into
end.
build_dispatch(Opts) ->
#{udp_template => maps:get(uri_template, Opts),
udp_handler => maps:get(handler, Opts),
ip_template => maps:get(ip_uri_template, Opts),
ip_handler => maps:get(ip_handler, Opts),
tcp_handler => maps:get(tcp_handler, Opts),
bind_handler => maps:get(bind_handler, Opts),
accept_bind => maps:get(accept_bind, Opts),
resolver => maps:get(resolver, Opts, fun default_resolver/1),
handler_opts => maps:merge(
maps:with([address_pool, routes, mtu,
resolver, allow, family,
allow_private, connect_timeout,
socket_opts,
bind_address, bind_port,
bind_socket_opts,
public_addresses, public_address_fun,
peer_filter_fun, scrub_fun,
allow_loopback,
max_compression_contexts,
max_compression_contexts_in,
max_compression_contexts_out,
max_pending_compression_responses],
Opts),
maps:get(handler_opts, Opts, #{})),
name => maps:get(drain_key, Opts, undefined)}.
default_resolver(Host) when is_binary(Host) ->
default_resolver(binary_to_list(Host));
default_resolver(Host) when is_list(Host) ->
V4 = case inet_res:lookup(Host, in, a) of
[] -> []; Xs -> Xs
end,
V6 = case inet_res:lookup(Host, in, aaaa) of
[] -> []; Ys -> Ys
end,
case V4 ++ V6 of
[] -> {error, nxdomain};
Addrs -> {ok, Addrs}
end.
make_dispatch_fun(Dispatch) ->
fun(Conn, StreamId, Method, Path, Headers) ->
dispatch_request(Conn, StreamId, Method, Path, Headers, Dispatch)
end.
dispatch_request(Conn, StreamId, Method, Path, Headers, Dispatch) ->
case masque:is_draining(maps:get(name, Dispatch, undefined)) of
true ->
reject(Conn, StreamId, overload);
false ->
dispatch_request_1(Conn, StreamId, Method, Path, Headers,
Dispatch)
end.
dispatch_request_1(Conn, StreamId, Method, Path, Headers, Dispatch) ->
#{udp_template := UdpTpl,
udp_handler := UdpHandler,
ip_template := IpTpl,
ip_handler := IpHandler,
tcp_handler := TcpHandler,
handler_opts := HandlerOpts} = Dispatch,
BindHandler = maps:get(bind_handler, Dispatch,
masque_udp_bind_proxy_handler),
AcceptBind = maps:get(accept_bind, Dispatch, false),
case validate(Method, Path, Headers, UdpTpl, IpTpl, AcceptBind) of
{ok, Req0} ->
Protocol = maps:get(protocol, Req0),
HandlerMod = case Protocol of
udp -> UdpHandler;
ip -> IpHandler;
tcp -> TcpHandler;
udp_bind -> BindHandler
end,
Req = Req0#{handler_opts => HandlerOpts},
case accept_request(HandlerMod, Req) of
accept ->
spawn_session(Conn, StreamId, Protocol, HandlerMod,
HandlerOpts, Req);
{reject, Reason} ->
reject(Conn, StreamId, Reason);
{reject, Reason, Extra} when is_list(Extra) ->
reject(Conn, StreamId, Reason, Extra)
end;
{error, Reason} ->
reject(Conn, StreamId, Reason)
end.
spawn_session(Conn, StreamId, Protocol, Handler, HOpts, Req) ->
Args = #{conn => Conn, stream_id => StreamId,
protocol => Protocol, transport => h1,
handler => Handler, handler_opts => HOpts, req => Req},
case masque_h1_session_sup:start_session(Args) of
{ok, _Pid} ->
ok;
{error, Reason} ->
reject(Conn, StreamId, map_init_error(Reason))
end.
map_init_error({reject, Err}) -> Err;
map_init_error(_) -> resolution_failed.
validate(<<"GET">>, Path, Headers, UdpTemplate, IpTemplate) ->
validate_get(Path, Headers, UdpTemplate, IpTemplate, false);
validate(<<"CONNECT">>, Path, Headers, _UdpTemplate, _IpTemplate) ->
%% RFC 9110 §9.3.6 + RFC 9112 §3.2.3: CONNECT request-target is
%% authority-form (`host:port' / `[ipv6]:port').
case masque_uri:parse_authority_form(Path) of
{ok, Host, Port} ->
case check_connect_host(Headers, Path) of
ok ->
Authority = header(<<"host">>, Headers, Path),
{ok, #{
method => <<"CONNECT">>,
protocol => tcp,
path => Path,
authority => Authority,
scheme => <<"https">>,
target_host => Host,
target_port => Port,
headers => Headers
}};
{error, Reason} ->
{error, Reason}
end;
{error, bad_port} -> {error, bad_port};
{error, bad_host} -> {error, bad_host};
{error, _} -> {error, bad_path}
end;
validate(_, _Path, _Headers, _UdpTemplate, _IpTemplate) ->
{error, bad_method}.
%% Same shape as `validate/5' plus the listener-level `AcceptBind'
%% switch. When true, the GET branch additionally inspects the
%% `Connect-UDP-Bind' request header and routes to the bind matcher.
validate(<<"GET">>, Path, Headers, UdpTemplate, IpTemplate, AcceptBind) ->
validate_get(Path, Headers, UdpTemplate, IpTemplate, AcceptBind);
validate(Method, Path, Headers, UdpTemplate, IpTemplate, _AcceptBind) ->
validate(Method, Path, Headers, UdpTemplate, IpTemplate).
validate_get(Path, Headers, UdpTemplate, IpTemplate, AcceptBind) ->
case header(<<"host">>, Headers) of
undefined ->
{error, bad_host};
_ ->
Upgrade = header(<<"upgrade">>, Headers),
Capsule = header(<<"capsule-protocol">>, Headers),
UpgradeLc = lowercase_bin(Upgrade),
case {UpgradeLc, Capsule} of
{?MASQUE_CONNECT_UDP_PROTOCOL, <<"?1">>}
when AcceptBind ->
match_udp_or_bind_path(Path, Headers, UdpTemplate);
{?MASQUE_CONNECT_UDP_PROTOCOL, <<"?1">>} ->
match_path(Path, Headers, UdpTemplate);
{?MASQUE_CONNECT_IP_PROTOCOL, <<"?1">>} ->
match_ip_path(Path, Headers, IpTemplate);
{Upgrade1, _} when Upgrade1 =:= ?MASQUE_CONNECT_UDP_PROTOCOL;
Upgrade1 =:= ?MASQUE_CONNECT_IP_PROTOCOL ->
{error, bad_protocol};
{undefined, _} ->
{error, bad_protocol};
_ ->
{error, bad_protocol}
end
end.
%% When the listener has bind enabled, the bind matcher is tried
%% against the same UDP template (per draft-11 the URI is shared)
%% only when the Connect-UDP-Bind: ?1 header is present.
match_udp_or_bind_path(Path, Headers, Template) ->
case masque_uri_udp_bind:parse_bind_header(Headers) of
bind ->
case masque_uri_udp_bind:match(Template, Path) of
{ok, #{target_host := Host, target_port := Port,
bind := Scope}} ->
{ok, #{
method => <<"GET">>,
protocol => udp_bind,
bind => Scope,
path => Path,
authority => header(<<"host">>, Headers, <<"">>),
scheme => <<"https">>,
target_host => Host,
target_port => Port,
headers => Headers
}};
{error, bad_port} -> {error, bad_port};
{error, bad_host} -> {error, bad_host};
{error, _} -> {error, bad_path}
end;
_ ->
match_path(Path, Headers, Template)
end.
%% Host header on a CONNECT request must be present and parse to the
%% same host:port as the request-target (RFC 9112 §3.2.3). Case-
%% insensitive comparison on the host part; ports compare as integers.
check_connect_host(Headers, Path) ->
case header(<<"host">>, Headers) of
undefined ->
{error, bad_host};
HostHeader ->
case {masque_uri:parse_authority_form(Path),
masque_uri:parse_authority_form(HostHeader)} of
{{ok, H1, P1}, {ok, H2, P2}} ->
case ci_eq(H1, H2) andalso P1 =:= P2 of
true -> ok;
false -> {error, bad_host}
end;
_ ->
{error, bad_host}
end
end.
match_path(Path, Headers, Template) ->
case masque_uri:match(Template, Path) of
{ok, #{target_host := Host, target_port := Port}} ->
Authority = header(<<"host">>, Headers, <<>>),
{ok, #{
method => <<"GET">>,
protocol => udp,
path => Path,
authority => Authority,
scheme => <<"https">>,
target_host => Host,
target_port => Port,
headers => Headers
}};
{error, bad_port} -> {error, bad_port};
{error, bad_host} -> {error, bad_host};
{error, _} -> {error, bad_path}
end.
match_ip_path(Path, Headers, Template) ->
case masque_uri_ip:parse_server_template(Template) of
{ok, T} ->
case masque_uri_ip:match(T, Path) of
{ok, #{target := Target, ipproto := IPProto}} ->
Authority = header(<<"host">>, Headers, <<>>),
{ok, #{
method => <<"GET">>,
protocol => ip,
path => Path,
authority => Authority,
scheme => <<"https">>,
ip_target => Target,
ip_ipproto => IPProto,
headers => Headers
}};
{error, bad_target} -> {error, bad_host};
{error, bad_ipproto} -> {error, bad_port};
{error, _} -> {error, bad_path}
end;
{error, _} ->
{error, bad_path}
end.
accept_request(HandlerMod, Req) ->
_ = code:ensure_loaded(HandlerMod),
case erlang:function_exported(HandlerMod, accept, 1) of
true -> HandlerMod:accept(Req);
false -> masque_handler:default_accept(Req)
end.
header(Name, Headers) ->
case lists:search(fun({N, _}) -> ci_eq(N, Name) end, Headers) of
{value, {_, V}} -> V;
false -> undefined
end.
header(Name, Headers, Default) ->
case header(Name, Headers) of
undefined -> Default;
V -> V
end.
ci_eq(A, B) ->
lowercase_bin(A) =:= lowercase_bin(B).
lowercase_bin(undefined) -> undefined;
lowercase_bin(B) when is_binary(B) ->
list_to_binary(string:to_lower(binary_to_list(B)));
lowercase_bin(L) when is_list(L) ->
lowercase_bin(iolist_to_binary(L)).
reject(Conn, StreamId, Reason) ->
reject(Conn, StreamId, Reason, []).
reject(Conn, StreamId, Reason, ExtraHeaders) ->
masque_metrics:tunnel_rejected(#{reason => Reason}),
Status = masque_errors:handshake_status(Reason),
Phrase = masque_errors:status_reason(Reason),
Body = <<Phrase/binary, "\n">>,
%% RFC 9931 (updates RFC 9298): a proxy that rejects an HTTP/1.1
%% CONNECT/Upgrade MUST close the underlying connection, otherwise
%% the client may treat subsequent bytes on the wire as belonging
%% to the rejected resource.
Base = [
{<<"content-type">>, <<"text/plain; charset=utf-8">>},
{<<"content-length">>, integer_to_binary(byte_size(Body))},
{<<"connection">>, <<"close">>},
{<<"proxy-status">>, proxy_status_field(Reason)}
],
Headers = merge_extra_headers(Base, ExtraHeaders),
_ = (try h1:send_response(Conn, StreamId, Status, Headers) catch _:_ -> ok end),
_ = (try h1:send_data(Conn, StreamId, Body, true) catch _:_ -> ok end),
_ = (try h1:close(Conn) catch _:_ -> ok end),
ok.
merge_extra_headers(Base, []) ->
Base;
merge_extra_headers(Base, Extra) ->
Keys = [K || {K, _} <- Extra],
Kept = [Pair || {K, _} = Pair <- Base, not lists:member(K, Keys)],
Extra ++ Kept.
proxy_status_field(Reason) ->
Error = proxy_status_error(Reason),
<<"masque; error=", Error/binary>>.
proxy_status_error(bad_method) -> <<"http_protocol_error">>;
proxy_status_error(bad_protocol) -> <<"http_protocol_error">>;
proxy_status_error(bad_path) -> <<"http_protocol_error">>;
proxy_status_error(bad_port) -> <<"http_protocol_error">>;
proxy_status_error(bad_host) -> <<"http_protocol_error">>;
proxy_status_error(resolution_failed) -> <<"dns_error">>;
proxy_status_error(forbidden) -> <<"destination_ip_prohibited">>;
proxy_status_error(overload) -> <<"proxy_internal_error">>;
proxy_status_error(_) -> <<"proxy_internal_error">>.