%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2003-2016. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%%---------------------------------------------------------------
%% Basic negotiated options with Telnet (RFC 854)
%%
%% Side A request: I WILL set option Opt.
%% Side B answer: DO go ahead, or no, DON'T set it.
%%
%% Side A request: Please DO set this option.
%% Side B answer: Ok I WILL, or no, I WON'T set it.
%%
%% "Enable option" requests may be rejected.
%% "Disable option" requests must not.
%%---------------------------------------------------------------
-module(ct_telnet_client).
%%-define(debug, true).
-export([open/2, open/3, open/4, open/5, close/1]).
-export([send_data/2, send_data/3, get_data/1]).
-define(TELNET_PORT, 23).
-define(OPEN_TIMEOUT,10000).
-define(IDLE_TIMEOUT,8000).
%% telnet control characters
-define(SE, 240).
-define(NOP, 241).
-define(DM, 242).
-define(BRK, 243).
-define(IP, 244).
-define(AO, 245).
-define(AYT, 246).
-define(EC, 247).
-define(EL, 248).
-define(GA, 249).
-define(SB, 250).
-define(WILL, 251).
-define(WONT, 252).
-define(DO, 253).
-define(DONT, 254).
-define(IAC, 255).
%% telnet options
-define(BINARY, 0).
-define(ECHO, 1).
-define(SUPPRESS_GO_AHEAD, 3).
-define(TERMINAL_TYPE, 24).
-define(WINDOW_SIZE, 31).
-record(state,{conn_name, get_data, keep_alive=true, log_pos=1}).
open(Server, ConnName) ->
open(Server, ?TELNET_PORT, ?OPEN_TIMEOUT, true, ConnName).
open(Server, Port, ConnName) ->
open(Server, Port, ?OPEN_TIMEOUT, true, ConnName).
open(Server, Port, Timeout, ConnName) ->
open(Server, Port, Timeout, true, ConnName).
open(Server, Port, Timeout, KeepAlive, ConnName) ->
Self = self(),
Pid = spawn(fun() ->
init(Self, Server, Port, Timeout,
KeepAlive, ConnName)
end),
receive
{open,Pid} ->
{ok,Pid};
{Error,Pid} ->
Error
end.
close(Pid) ->
Pid ! {close,self()},
receive closed -> ok
after 5000 -> ok
end.
send_data(Pid, Data) ->
send_data(Pid, Data, true).
send_data(Pid, Data, true) ->
send_data(Pid, Data++"\n", false);
send_data(Pid, Data, false) ->
Pid ! {send_data, Data},
ok.
get_data(Pid) ->
Pid ! {get_data,self()},
receive
{data,Data} ->
{ok,Data}
end.
%%%-----------------------------------------------------------------
%%% Internal functions
init(Parent, Server, Port, Timeout, KeepAlive, ConnName) ->
case gen_tcp:connect(Server, Port, [list,{packet,0},{nodelay,true}], Timeout) of
{ok,Sock} ->
dbg("~p connected to: ~p (port: ~w, keep_alive: ~w)\n",
[ConnName,Server,Port,KeepAlive]),
send([?IAC,?DO,?SUPPRESS_GO_AHEAD], Sock, ConnName),
Parent ! {open,self()},
loop(#state{conn_name=ConnName, get_data=10, keep_alive=KeepAlive},
Sock, []),
gen_tcp:close(Sock);
Error ->
Parent ! {Error,self()}
end.
loop(State, Sock, Acc) ->
receive
{tcp_closed,_} ->
dbg("Connection closed\n", []),
Data = lists:reverse(lists:append(Acc)),
dbg("Printing queued messages: ~tp",[Data]),
ct_telnet:log(State#state.conn_name,
general_io, "~ts",
[lists:sublist(Data,
State#state.log_pos,
length(Data))]),
receive
{get_data,Pid} ->
Pid ! closed
after 100 ->
ok
end;
{tcp,_,Msg0} ->
dbg("rcv tcp msg: ~tp~n",[Msg0]),
Msg = check_msg(Sock,Msg0,[]),
loop(State, Sock, [Msg | Acc]);
{send_data,Data} ->
send(Data, Sock, State#state.conn_name),
loop(State, Sock, Acc);
{get_data,Pid} ->
NewState =
case Acc of
[] ->
dbg("get_data nodata\n",[]),
erlang:send_after(100,self(),{get_data_delayed,Pid}),
if State#state.keep_alive == true ->
State#state{get_data=State#state.get_data - 1};
State#state.keep_alive == false ->
State
end;
_ ->
Data = lists:reverse(lists:append(Acc)),
Len = length(Data),
dbg("get_data ~tp\n",[Data]),
ct_telnet:log(State#state.conn_name,
general_io, "~ts",
[lists:sublist(Data,
State#state.log_pos,
Len)]),
Pid ! {data,Data},
State#state{log_pos = 1}
end,
loop(NewState, Sock, []);
{get_data_delayed,Pid} ->
NewState =
case State of
#state{keep_alive = true, get_data = 0} ->
dbg("sending NOP\n",[]),
if Acc == [] -> send([?IAC,?NOP], Sock,
State#state.conn_name);
true -> ok
end,
State#state{get_data=10};
_ ->
State
end,
{NewAcc,Pos} =
case erlang:is_process_alive(Pid) of
true when Acc /= [] ->
Data = lists:reverse(lists:append(Acc)),
Len = length(Data),
dbg("get_data_delayed ~tp\n",[Data]),
ct_telnet:log(State#state.conn_name,
general_io, "~ts",
[lists:sublist(Data,
State#state.log_pos,
Len)]),
Pid ! {data,Data},
{[],1};
true when Acc == [] ->
dbg("get_data_delayed nodata\n",[]),
Pid ! {data,[]},
{[],1};
false ->
{Acc,NewState#state.log_pos}
end,
loop(NewState#state{log_pos=Pos}, Sock, NewAcc);
{close,Pid} ->
dbg("Closing connection\n", []),
if Acc == [] ->
ok;
true ->
Data = lists:reverse(lists:append(Acc)),
dbg("Printing queued messages: ~tp",[Data]),
ct_telnet:log(State#state.conn_name,
general_io, "~ts",
[lists:sublist(Data,
State#state.log_pos,
length(Data))])
end,
gen_tcp:close(Sock),
Pid ! closed
after wait(State#state.keep_alive,?IDLE_TIMEOUT) ->
dbg("idle timeout\n",[]),
Data = lists:reverse(lists:append(Acc)),
case Data of
[] ->
dbg("sending NOP\n",[]),
send([?IAC,?NOP], Sock, State#state.conn_name),
loop(State, Sock, Acc);
_ when State#state.log_pos == length(Data)+1 ->
loop(State, Sock, Acc);
_ ->
dbg("idle timeout, printing ~tp\n",[Data]),
Len = length(Data),
ct_telnet:log(State#state.conn_name,
general_io, "~ts",
[lists:sublist(Data,
State#state.log_pos,
Len)]),
loop(State#state{log_pos = Len+1}, Sock, Acc)
end
end.
wait(true, Time) -> Time;
wait(false, _) -> infinity.
send(Data, Sock, ConnName) ->
case Data of
[?IAC|_] = Cmd ->
cmd_dbg("Sending",Cmd),
try io_lib:format("[~w] ~w", [?MODULE,Data]) of
Str ->
ct_telnet:log(ConnName, general_io, Str, [])
catch
_:_ -> ok
end;
_ ->
dbg("Sending: ~tp\n", [Data]),
try io_lib:format("[~w] ~ts", [?MODULE,Data]) of
Str ->
ct_telnet:log(ConnName, general_io, Str, [])
catch
_:_ -> ok
end
end,
gen_tcp:send(Sock, Data),
ok.
%% [IAC,IAC] = buffer data value 255
check_msg(Sock, [?IAC,?IAC | T], Acc) ->
check_msg(Sock, T, [?IAC|Acc]);
%% respond to a command
check_msg(Sock, [?IAC | Cs], Acc) ->
case get_cmd(Cs) of
{Cmd,Cs1} ->
cmd_dbg("Got",Cmd),
respond_cmd(Cmd, Sock),
check_msg(Sock, Cs1, Acc);
error ->
Acc
end;
%% buffer a data value
check_msg(Sock, [H|T], Acc) ->
check_msg(Sock, T, [H|Acc]);
check_msg(_Sock, [], Acc) ->
Acc.
%% Positive responses (WILL and DO).
respond_cmd([?WILL,?ECHO], Sock) ->
R = [?IAC,?DO,?ECHO],
cmd_dbg("Responding",R),
gen_tcp:send(Sock, R);
respond_cmd([?DO,?ECHO], Sock) ->
R = [?IAC,?WILL,?ECHO],
cmd_dbg("Responding",R),
gen_tcp:send(Sock, R);
%% Answers from server
respond_cmd([?WILL,?SUPPRESS_GO_AHEAD], _Sock) ->
dbg("Server will suppress-go-ahead\n", []);
respond_cmd([?WONT,?SUPPRESS_GO_AHEAD], _Sock) ->
dbg("Warning! Server won't suppress-go-ahead\n", []);
respond_cmd([?DONT | _Opt], _Sock) -> % server ack?
ok;
respond_cmd([?WONT | _Opt], _Sock) -> % server ack?
ok;
%% Negative responses (WON'T and DON'T). These are default!
respond_cmd([?WILL,Opt], Sock) ->
R = [?IAC,?DONT,Opt],
cmd_dbg("Responding",R),
gen_tcp:send(Sock, R);
respond_cmd([?DO | Opt], Sock) ->
R = [?IAC,?WONT | Opt],
cmd_dbg("Responding",R),
gen_tcp:send(Sock, R);
%% Commands without options (which we ignore)
respond_cmd(?NOP, _Sock) ->
ok;
%% Unexpected messages.
respond_cmd([Cmd | Opt], _Sock) when Cmd >= 240, Cmd =< 255 ->
dbg("Received cmd: ~w. Ignored!\n", [[Cmd | Opt]]);
respond_cmd([Cmd | Opt], _Sock) ->
dbg("WARNING: Received unknown cmd: ~w. Ignored!\n", [[Cmd | Opt]]).
get_cmd([Cmd | Rest]) when Cmd == ?SB ->
get_subcmd(Rest, []);
get_cmd([Cmd | Rest]) when Cmd >= 240, Cmd =< 249 ->
{?NOP, Rest};
get_cmd([Cmd,Opt | Rest]) when Cmd >= 251, Cmd =< 254 ->
{[Cmd,Opt], Rest};
get_cmd(_Other) ->
error.
get_subcmd([?SE | Rest], Acc) ->
{[?SE | lists:reverse(Acc)], Rest};
get_subcmd([Opt | Rest], Acc) ->
get_subcmd(Rest, [Opt | Acc]).
-ifdef(debug).
dbg(Str,Args) ->
TS = timestamp(),
io:format("[~p ct_telnet_client, ~s]\n" ++ Str,[self(),TS|Args]).
cmd_dbg(Prefix,Cmd) ->
case Cmd of
[?IAC|Cmd1] ->
cmd_dbg(Prefix,Cmd1);
[Ctrl|Opts] ->
CtrlStr =
case Ctrl of
?DO -> "DO";
?DONT -> "DONT";
?WILL -> "WILL";
?WONT -> "WONT";
?NOP -> "NOP";
_ -> "CMD"
end,
Opts1 =
case Opts of
[Opt] -> Opt;
_ -> Opts
end,
dbg("~ts: ~ts(~w): ~w\n", [Prefix,CtrlStr,Ctrl,Opts1]);
Any ->
dbg("Unexpected in cmd_dbg:~n~w~n",[Any])
end.
timestamp() ->
{MS,S,US} = os:timestamp(),
{{Year,Month,Day}, {Hour,Min,Sec}} =
calendar:now_to_local_time({MS,S,US}),
MilliSec = trunc(US/1000),
lists:flatten(io_lib:format("~4.10.0B-~2.10.0B-~2.10.0B "
"~2.10.0B:~2.10.0B:~2.10.0B.~3.10.0B",
[Year,Month,Day,Hour,Min,Sec,MilliSec])).
-else.
dbg(_Str,_Args) ->
ok.
cmd_dbg(_Prefix,_Cmd) ->
ok.
-endif.
