enoise/src/enoise_connection.erl
2018-03-07 11:23:21 +01:00

130 lines
4.5 KiB
Erlang

%%%-------------------------------------------------------------------
%%% @copyright (C) 2018, Aeternity Anstalt
%%%-------------------------------------------------------------------
-module(enoise_connection).
-export([ close/1
, recv/3
, send/2
, start_link/5
]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-record(enoise, { pid }).
-record(state, {rx, tx, owner, tcp_sock, active, buf = <<>>, rawbuf = <<>>}).
%% -- API --------------------------------------------------------------------
start_link(TcpSock, Rx, Tx, Owner, Active) ->
inet:setopts(TcpSock, [{active, Active}]),
State = #state{ rx = Rx, tx = Tx, owner = Owner,
tcp_sock = TcpSock, active = Active },
case gen_server:start_link(?MODULE, [State], []) of
{ok, Pid} ->
ok = gen_tcp:controlling_process(TcpSock, Pid),
{ok, Pid};
Err = {error, _} ->
Err
end.
send(Noise, Data) ->
gen_server:call(Noise, {send, Data}).
recv(Noise, Length, Timeout) ->
gen_server:call(Noise, {recv, Length, Timeout}, Timeout + 100).
close(Noise) ->
gen_server:call(Noise, close).
%% -- gen_server callbacks ---------------------------------------------------
init([State]) ->
{ok, State}.
handle_call({send, Data}, _From, S) ->
{Res, S1} = handle_send(S, Data),
{reply, Res, S1};
handle_call({recv, _Length, _Timeout}, _From, S = #state{ active = true }) ->
{reply, {error, active_socket}, S};
handle_call({recv, Length, Timeout}, _From, S) ->
{Res, S1} = handle_recv(S, Length, Timeout),
{reply, Res, S1};
handle_call(close, _From, S) ->
{stop, normal, ok, S}.
handle_cast(_Msg, S) ->
{noreply, S}.
handle_info({tcp, TS, Data}, S = #state{ tcp_sock = TS }) ->
{S1, Msgs} = handle_data(S, Data),
S2 = handle_msgs(S1, Msgs),
{noreply, S2};
handle_info({tcp_closed, TS}, S = #state{ tcp_sock = TS, active = A, owner = O }) ->
[ O ! {tcp_closed, TS} || A ],
{stop, tcp_closed, S};
handle_info(Msg, S) ->
io:format("Unexpected info: ~p\n", [Msg]),
{noreply, S}.
terminate(Reason, #state{ tcp_sock = TcpSock }) ->
[ gen_tcp:close(TcpSock) || Reason /= tcp_closed ],
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%% -- Local functions --------------------------------------------------------
handle_data(S = #state{ rawbuf = Buf, rx = Rx }, Data) ->
case <<Buf/binary, Data/binary>> of
B = <<Len:16, Rest/binary>> when Len < byte_size(Rest) ->
{S#state{ rawbuf = B }, []}; %% Not a full message - save it
<<Len:16, Rest/binary>> ->
<<Msg:Len/binary, Rest2/binary>> = Rest,
case enoise_cipher_state:decrypt_with_ad(Rx, <<>>, Msg) of
{ok, Rx1, Msg1} ->
{S1, Msgs} = handle_data(S#state{ rawbuf = Rest2, rx = Rx1 }, <<>>),
{S1, [Msg1 | Msgs]};
{error, _} ->
error({enoise_error, decrypt_input_failed})
end;
EmptyOrSingleByte ->
{S#state{ rawbuf = EmptyOrSingleByte }, []}
end.
handle_msgs(S, []) ->
S;
handle_msgs(S = #state{ active = true, owner = Owner, buf = <<>> }, Msgs) ->
[ Owner ! {noise, #enoise{ pid = self() }, Msg} || Msg <- Msgs ],
S;
handle_msgs(S = #state{ active = true, owner = Owner, buf = Buf }, Msgs) ->
%% First send stuff in buffer (only when switching to active true)
Owner ! {noise, #enoise{ pid = self() }, Buf},
handle_msgs(S#state{ buf = <<>> }, Msgs);
handle_msgs(S = #state{ buf = Buf }, Msgs) ->
NewBuf = lists:foldl(fun(Msg, B) -> <<B/binary, Msg/binary>> end, Buf, Msgs),
S#state{ buf = NewBuf }.
handle_send(S = #state{ tcp_sock = TcpSock, tx = Tx }, Data) ->
{ok, Tx1, Msg} = enoise_cipher_state:encrypt_with_ad(Tx, <<>>, Data),
gen_tcp:send(TcpSock, <<(byte_size(Msg)):16, Msg/binary>>),
{ok, S#state{ tx = Tx1 }}.
handle_recv(S = #state{ buf = Buf, rx = Rx, tcp_sock = TcpSock }, Len, TO)
when byte_size(Buf) < Len ->
{ok, <<MsgLen:16>>} = gen_tcp:recv(TcpSock, 2, TO),
{ok, Data} = gen_tcp:recv(TcpSock, MsgLen, TO),
case enoise_cipher_state:decrypt_with_ad(Rx, <<>>, Data) of
{ok, Rx1, Msg1} ->
handle_recv(S#state{ buf = <<Buf/binary, Msg1/binary>>, rx = Rx1 }, Len, TO);
{error, _} ->
error({enoise_error, decrypt_input_failed})
end;
handle_recv(S = #state{ buf = Buf }, Len, _TO) ->
<<Data:Len/binary, NewBuf/binary>> = Buf,
{{ok, Data}, S#state{ buf = NewBuf }}.