[common_test] Add telnet server to use for testing

2 files changed, 218 insertions, 0 deletions

diff --git a/lib/common_test/test/Makefile b/lib/common_test/test/Makefile
index 94569fa87f..31ab28c41d 100644
--- a/lib/common_test/test/Makefile
+++ b/lib/common_test/test/Makefile
@@ -28,6 +28,7 @@ MODULES= \
 	ct_test_support \
 	ct_test_support_eh \
 	ct_userconfig_callback \
+	telnet_server \
 	ct_smoke_test_SUITE \
 	ct_priv_dir_SUITE \
 	ct_event_handler_SUITE \
diff --git a/lib/common_test/test/telnet_server.erl b/lib/common_test/test/telnet_server.erl
new file mode 100644
index 0000000000..5843155eee
--- /dev/null
+++ b/lib/common_test/test/telnet_server.erl
@@ -0,0 +1,217 @@
+-module(telnet_server).
+-compile(export_all).
+
+%% 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).  
+
+-record(state,
+	{listen,
+	 client,
+	 users,
+	 authorized=false,
+	 suppress_go_ahead=false,
+	 buffer=[]}).
+
+-type options() :: [{port,pos_integer()} | {users,users()}].
+-type users() :: [{user(),password()}].
+-type user() :: string().
+-type password() :: string(). 
+
+-spec start(Opts::options()) -> Pid::pid().
+start(Opts) when is_list(Opts) ->
+    spawn_link(fun() -> init(Opts) end).
+
+-spec stop(Pid::pid()) -> ok.
+stop(Pid) ->
+    Ref = erlang:monitor(process,Pid),
+    Pid ! stop,
+    receive {'DOWN',Ref,_,_,_} -> ok end.
+
+init(Opts) ->
+    Port = proplists:get_value(port,Opts),
+    Users = proplists:get_value(users,Opts,[]),
+    {ok, LSock} = gen_tcp:listen(Port, [list, {packet, 0}, 
+                                        {active, true}]),
+    State = #state{listen=LSock,users=Users},
+    accept(State),
+    ok = gen_tcp:close(LSock).
+
+accept(#state{listen=LSock}=State) ->
+    Server = self(),
+    Acceptor = spawn_link(fun() -> do_accept(LSock,Server) end),
+    receive 
+	{Acceptor,Sock} when is_port(Sock) ->
+	    case init_client(State#state{client=Sock}) of
+		stopped ->
+		    io:format("telnet_server stopped\n"),
+		    ok;
+		R ->
+		    io:format("connection to client closed with reason ~p~n",[R]),
+		    accept(State)
+	    end;
+	{Acceptor,closed} ->
+	    io:format("listen socket closed unexpectedly, "
+		      "terminating telnet_server\n"),
+	    ok;
+	stop  ->
+	    io:format("telnet_server stopped\n"),
+	    ok
+    end.
+
+do_accept(LSock,Server) ->
+    case gen_tcp:accept(LSock) of
+	{ok, Sock} ->
+	    ok = gen_tcp:controlling_process(Sock,Server),
+	    Server ! {self(),Sock};
+	{error,closed} ->
+	    %% This will happen when stop/1 is called, since listen
+	    %% socket is closed. Then the server is probably already
+	    %% dead by now, but to be 100% sure not to hang, we send a
+	    %% message to say what happened.
+	    Server ! {self(),closed}
+    end.
+
+init_client(#state{client=Sock}=State) ->
+    R = case gen_tcp:send(Sock,"login: ") of
+	    ok ->
+		loop(State);
+	    Error ->
+		Error
+	end,
+    _ = gen_tcp:close(Sock),
+    R.
+
+loop(State) ->
+    receive
+	{tcp,_,Data} ->
+	    try handle_data(Data,State) of
+		{ok,State1} ->
+		    loop(State1)
+	    catch 
+		throw:Error ->
+		    Error
+	    end;
+        {tcp_closed, _} ->
+            closed;
+	{tcp_error,_,Error} ->
+	    {error,tcp,Error};
+	stop ->
+	    stopped
+    end.
+
+handle_data([?IAC|Cmd],State) ->
+    dbg("Server got cmd: ~p~n",[Cmd]),
+    handle_cmd(Cmd,State);
+handle_data(Data,State) ->
+    dbg("Server got data: ~p~n",[Data]),
+    case get_line(Data,[]) of
+	{Line,Rest} ->
+	    WholeLine = lists:flatten(lists:reverse(State#state.buffer,Line)),
+	    {ok,State1} = do_handle_data(WholeLine,State),
+	    case Rest of
+		[] -> {ok,State1};
+		_ -> handle_data(Rest,State1)
+	    end;
+	false ->
+	    {ok,State#state{buffer=[Data|State#state.buffer]}}
+    end.
+
+%% Add function clause below to handle new telnet commands (sent with
+%% ?IAC from client - this is not possible to do from ct_telnet API,
+%% but ct_telnet sends DONT SUPPRESS_GO_AHEAD)
+handle_cmd([?DO,?SUPPRESS_GO_AHEAD|T],State) ->
+    send([?IAC,?WILL,?SUPPRESS_GO_AHEAD],State),
+    handle_cmd(T,State#state{suppress_go_ahead=true});
+handle_cmd([?DONT,?SUPPRESS_GO_AHEAD|T],State) ->
+    send([?IAC,?WONT,?SUPPRESS_GO_AHEAD],State),
+    handle_cmd(T,State#state{suppress_go_ahead=false});
+handle_cmd([?IAC|T],State) ->
+    %% Multiple commands in one packet
+    handle_cmd(T,State);
+handle_cmd([_H|T],State) ->
+    %% Not responding to this command
+    handle_cmd(T,State);
+handle_cmd([],State) ->
+    {ok,State}.
+
+%% Add function clause below to handle new text command (text entered
+%% from the telnet prompt)
+do_handle_data(Data,#state{authorized=false}=State) ->
+    check_user(Data,State);
+do_handle_data(Data,#state{authorized={user,_}}=State) ->
+    check_pwd(Data,State);
+do_handle_data("echo "++ Data,State) ->
+    send(Data++"\r\n> ",State),
+    {ok,State};
+do_handle_data("repeat "++ Data,State) ->
+    send(Data++"\r\n"++Data++"\r\n> ",State),
+    {ok,State};
+do_handle_data([],State) ->
+    send("> ",State),
+    {ok,State};
+do_handle_data(_Data,State) ->
+    send("error: unknown command\r\n> ",State),
+    {ok,State}.
+
+check_user(User,State) ->
+    case lists:keyfind(User,1,State#state.users) of
+	{User,Pwd} ->
+	   dbg("user ok\n"),
+	    send("Password: ",State),
+	    {ok,State#state{authorized={user,Pwd}}};
+	false ->
+	    throw({error,unknown_user})
+    end.
+
+check_pwd(Pwd,#state{authorized={user,Pwd}}=State) ->
+    dbg("password ok\n"),
+    send("Welcome to the ultimate telnet server!\r\n> ",State),
+    {ok,State#state{authorized=true}};
+check_pwd(_,_State) ->
+    throw({error,authentication}).
+
+send(Data,State) ->
+    dbg("Server sending: ~p~n",[Data]),
+    case gen_tcp:send(State#state.client,Data) of
+	ok ->
+	    ok;
+	{error,Error} ->
+	    throw({error,send,Error})
+    end.
+    
+get_line([$\r,$\n|Rest],Acc) ->
+    {lists:reverse(Acc),Rest};
+get_line([$\r,0|Rest],Acc) ->
+    {lists:reverse(Acc),Rest};
+get_line([$\n|Rest],Acc) ->
+    {lists:reverse(Acc),Rest};
+get_line([H|T],Acc) ->
+    get_line(T,[H|Acc]);
+get_line([],_) ->
+    false.
+
+dbg(_F) ->
+    io:format(_F).
+dbg(_F,_A) ->
+    io:format(_F,_A).