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Diffstat (limited to 'lib/common_test/test/telnet_server.erl')
| -rw-r--r-- | lib/common_test/test/telnet_server.erl | 217 |
1 files changed, 217 insertions, 0 deletions
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). |