%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 1998-2018. 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% %% %% %% Test the behavior of gen_udp. Testing udp is really a very unfunny task, %% because udp is not deterministic. %% -module(gen_udp_SUITE). -include_lib("common_test/include/ct.hrl"). %% XXX - we should pick a port that we _know_ is closed. That's pretty hard. -define(CLOSED_PORT, 6666). -export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1, init_per_group/2,end_per_group/2]). -export([init_per_testcase/2, end_per_testcase/2]). -export([send_to_closed/1, active_n/1, buffer_size/1, binary_passive_recv/1, max_buffer_size/1, bad_address/1, read_packets/1, open_fd/1, connect/1, implicit_inet6/1, local_basic/1, local_unbound/1, local_fdopen/1, local_fdopen_unbound/1, local_abstract/1]). suite() -> [{ct_hooks,[ts_install_cth]}, {timetrap,{minutes,1}}]. all() -> [send_to_closed, buffer_size, binary_passive_recv, max_buffer_size, bad_address, read_packets, open_fd, connect, implicit_inet6, active_n, {group, local}]. groups() -> [{local, [], [local_basic, local_unbound, local_fdopen, local_fdopen_unbound, local_abstract]}]. init_per_suite(Config) -> Config. end_per_suite(_Config) -> ok. init_per_group(local, Config) -> case gen_udp:open(0, [local]) of {ok,S} -> ok = gen_udp:close(S), Config; {error,eafnosupport} -> {skip, "AF_LOCAL not supported"} end; init_per_group(_GroupName, Config) -> Config. end_per_group(local, _Config) -> delete_local_filenames(); end_per_group(_GroupName, Config) -> Config. init_per_testcase(_Case, Config) -> Config. end_per_testcase(_Case, _Config) -> ok. %%------------------------------------------------------------- %% Send two packets to a closed port (on some systems this causes the socket %% to be closed). %% Tests core functionality. send_to_closed(Config) when is_list(Config) -> {ok, Sock} = gen_udp:open(0), ok = gen_udp:send(Sock, {127,0,0,1}, ?CLOSED_PORT, "foo"), timer:sleep(2), ok = gen_udp:send(Sock, {127,0,0,1}, ?CLOSED_PORT, "foo"), ok = gen_udp:close(Sock), ok. %%------------------------------------------------------------- %% Test that the UDP socket buffer sizes are settable %% Test UDP buffer size setting. buffer_size(Config) when is_list(Config) -> Len = 256, Bin = list_to_binary(lists:seq(0, Len-1)), M = 8192 div Len, Spec0 = [{opt,M},{safe,M-3},{long,M+1}, {opt,2*M},{safe,2*M-3},{long,2*M+1}, {opt,4*M},{safe,4*M-3},{long,4*M+1}], Spec = [case Tag of opt -> [{recbuf,Val*Len},{sndbuf,(Val + 2)*Len}]; safe -> {list_to_binary(lists:duplicate(Val, Bin)), [correct]}; long -> {list_to_binary(lists:duplicate(Val, Bin)), [truncated,emsgsize,timeout]} end || {Tag,Val} <- Spec0], %% {ok, ClientSocket} = gen_udp:open(0, [binary]), {ok, ClientPort} = inet:port(ClientSocket), Client = self(), ClientIP = {127,0,0,1}, ServerIP = {127,0,0,1}, Server = spawn_link( fun () -> {ok, ServerSocket} = gen_udp:open(0, [binary]), {ok, ServerPort} = inet:port(ServerSocket), Client ! {self(),port,ServerPort}, buffer_size_server(Client, ClientIP, ClientPort, ServerSocket, 1, Spec), ok = gen_udp:close(ServerSocket) end), Mref = erlang:monitor(process, Server), receive {Server,port,ServerPort} -> buffer_size_client(Server, ServerIP, ServerPort, ClientSocket, 1, Spec) end, ok = gen_udp:close(ClientSocket), receive {'DOWN',Mref,_,_,normal} -> ok end. buffer_size_client(_, _, _, _, _, []) -> ok; buffer_size_client(Server, IP, Port, Socket, Cnt, [Opts|T]) when is_list(Opts) -> io:format("buffer_size_client Cnt=~w setopts ~p.~n", [Cnt,Opts]), ok = inet:setopts(Socket, Opts), Server ! {self(),setopts,Cnt}, receive {Server,setopts,Cnt} -> ok end, buffer_size_client(Server, IP, Port, Socket, Cnt+1, T); buffer_size_client(Server, IP, Port, Socket, Cnt, [{B,Replies}|T]=Opts) when is_binary(B) -> io:format( "buffer_size_client Cnt=~w send size ~w expecting ~p.~n", [Cnt,size(B),Replies]), ok = gen_udp:send(Socket, IP, Port, <>), receive {Server,Cnt,Reply} -> Tag = if is_tuple(Reply) -> element(1, Reply); is_atom(Reply) -> Reply end, case lists:member(Tag, Replies) of true -> ok; false -> ct:fail({reply_mismatch,Cnt,Reply,Replies, byte_size(B), inet:getopts(Socket, [sndbuf,recbuf])}) end, buffer_size_client(Server, IP, Port, Socket, Cnt+1, T) after 1313 -> buffer_size_client(Server, IP, Port, Socket, Cnt, Opts) end. buffer_size_server(_, _, _, _, _, []) -> ok; buffer_size_server(Client, IP, Port, Socket, Cnt, [Opts|T]) when is_list(Opts) -> receive {Client,setopts,Cnt} -> ok end, io:format("buffer_size_server Cnt=~w setopts ~p.~n", [Cnt,Opts]), ok = inet:setopts(Socket, Opts), Client ! {self(),setopts,Cnt}, buffer_size_server(Client, IP, Port, Socket, Cnt+1, T); buffer_size_server(Client, IP, Port, Socket, Cnt, [{B,_}|T]) when is_binary(B) -> io:format( "buffer_size_server Cnt=~w expecting size ~w.~n", [Cnt,size(B)]), Client ! {self(),Cnt, case buffer_size_server_recv(Socket, IP, Port, Cnt) of D when is_binary(D) -> SizeD = byte_size(D), io:format( "buffer_size_server Cnt=~w received size ~w.~n", [Cnt,SizeD]), case B of D -> correct; <> -> truncated; _ -> {unexpected,D} end; Error -> io:format( "buffer_size_server Cnt=~w received error ~w.~n", [Cnt,Error]), Error end}, buffer_size_server(Client, IP, Port, Socket, Cnt+1, T). buffer_size_server_recv(Socket, IP, Port, Cnt) -> receive {udp,Socket,IP,Port,<>} -> B; {udp,Socket,IP,Port,<<_/binary>>} -> buffer_size_server_recv(Socket, IP, Port, Cnt); {udp_error,Socket,Error} -> Error after 5000 -> {timeout,flush()} end. %%------------------------------------------------------------- %% OTP-15206: Keep buffer small for udp %%------------------------------------------------------------- max_buffer_size(Config) when is_list(Config) -> {ok, Socket} = gen_udp:open(0, [binary]), ok = inet:setopts(Socket,[{recbuf, 1 bsl 20}]), {ok, [{buffer, 65536}]} = inet:getopts(Socket,[buffer]), gen_udp:close(Socket). %%------------------------------------------------------------- %% OTP-3823 gen_udp:recv does not return address in binary mode %% %% OTP-3823 gen_udp:recv does not return address in binary mode. binary_passive_recv(Config) when is_list(Config) -> D1 = "The quick brown fox jumps over a lazy dog", D2 = list_to_binary(D1), D3 = ["The quick", <<" brown ">>, "fox jumps ", <<"over ">>, <<>>, $a, [[], " lazy ", <<"dog">>]], D2 = iolist_to_binary(D3), B = D2, {ok, R} = gen_udp:open(0, [binary, {active, false}]), {ok, RP} = inet:port(R), {ok, S} = gen_udp:open(0), {ok, SP} = inet:port(S), ok = gen_udp:send(S, localhost, RP, D1), {ok, {{127, 0, 0, 1}, SP, B}} = gen_udp:recv(R, byte_size(B)+1), ok = gen_udp:send(S, localhost, RP, D2), {ok, {{127, 0, 0, 1}, SP, B}} = gen_udp:recv(R, byte_size(B)+1), ok = gen_udp:send(S, localhost, RP, D3), {ok, {{127, 0, 0, 1}, SP, B}} = gen_udp:recv(R, byte_size(B)+1), ok = gen_udp:close(S), ok = gen_udp:close(R), ok. %%------------------------------------------------------------- %% OTP-3836 inet_udp crashes when IP-address is larger than 255. %% OTP-3836 inet_udp crashes when IP-address is larger than 255. bad_address(Config) when is_list(Config) -> {ok, R} = gen_udp:open(0), {ok, RP} = inet:port(R), {ok, S} = gen_udp:open(0), {ok, _SP} = inet:port(S), {'EXIT', badarg} = (catch gen_udp:send(S, {127,0,0,1,0}, RP, "void")), {'EXIT', badarg} = (catch gen_udp:send(S, {127,0,0,256}, RP, "void")), ok = gen_udp:close(S), ok = gen_udp:close(R), ok. %%------------------------------------------------------------- %% OTP-6249 UDP option for number of packet reads %% %% Starts a slave node that on command sends a bunch of messages %% to our UDP port. The receiving process just receives and %% ignores the incoming messages. %% A tracing process traces the receiving port for %% 'send' and scheduling events. From the trace, %% how many messages are received per in/out scheduling, %% which should never be more than the read_packet parameter. %% OTP-6249 UDP option for number of packet reads. read_packets(Config) when is_list(Config) -> N1 = 5, N2 = 1, Msgs = 30000, {ok,R} = gen_udp:open(0, [{read_packets,N1}]), {ok,RP} = inet:port(R), {ok,Node} = start_node(gen_udp_SUITE_read_packets), Die = make_ref(), %% {V1, Trace1} = read_packets_test(R, RP, Msgs, Node), {ok,[{read_packets,N1}]} = inet:getopts(R, [read_packets]), %% ok = inet:setopts(R, [{read_packets,N2}]), {V2, Trace2} = read_packets_test(R, RP, Msgs, Node), {ok,[{read_packets,N2}]} = inet:getopts(R, [read_packets]), %% stop_node(Node), ct:log("N1=~p, V1=~p vs N2=~p, V2=~p",[N1,V1,N2,V2]), dump_terms(Config, "trace1.terms", Trace2), dump_terms(Config, "trace2.terms", Trace2), %% Because of the inherit racy-ness of the feature it is %% hard to test that it behaves correctly. %% Right now (OTP 21) a port task takes 5% of the %% allotted port task reductions to execute, so %% the max number of executions a port is allowed to %% do before being re-scheduled is N * 20 if V1 > (N1 * 20) -> ct:fail("Got ~p msgs, max was ~p", [V1, N1]); V2 > (N2 * 20) -> ct:fail("Got ~p msgs, max was ~p", [V2, N2]); true -> ok end. dump_terms(Config, Name, Terms) -> FName = filename:join(proplists:get_value(priv_dir, Config),Name), file:write_file(FName, term_to_binary(Terms)), ct:log("Logged terms to ~s",[FName]). infinite_loop(Die) -> receive Die -> ok after 0 -> infinite_loop(Die) end. read_packets_test(R, RP, Msgs, Node) -> Receiver = self(), Tracer = spawn_link( fun () -> receive {Receiver,get_trace} -> Receiver ! {self(),{trace,flush()}} end end), Sender = spawn_opt( Node, fun () -> {ok,S} = gen_udp:open(0), {ok,SP} = inet:port(S), Receiver ! {self(),{port,SP}}, receive {Receiver,go} -> read_packets_send(S, RP, Msgs) end end, [link,{priority,high}]), receive {Sender,{port,SP}} -> erlang:trace(R, true, [running_ports,'send',{tracer,Tracer}]), erlang:yield(), Sender ! {Receiver,go}, read_packets_recv(Msgs), erlang:trace(R, false, [all]), Tracer ! {Receiver,get_trace}, receive {Tracer,{trace,Trace}} -> {read_packets_verify(R, SP, Trace), Trace} end end. read_packets_send(_S, _RP, 0) -> ok; read_packets_send(S, RP, Msgs) -> ok = gen_udp:send(S, localhost, RP, "UDP FLOOOOOOD"), read_packets_send(S, RP, Msgs - 1). read_packets_recv(0) -> ok; read_packets_recv(N) -> receive _ -> read_packets_recv(N - 1) after 5000 -> timeout end. read_packets_verify(R, SP, Trace) -> [Max | _] = Pkts = lists:reverse(lists:sort(read_packets_verify(R, SP, Trace, 0))), ct:pal("~p",[lists:sublist(Pkts,10)]), Max. read_packets_verify(R, SP, [{trace,R,OutIn,_}|Trace], M) when OutIn =:= out; OutIn =:= in -> push(M, read_packets_verify(R, SP, Trace, 0)); read_packets_verify(R, SP, [{trace, R,'receive',timeout}|Trace], M) -> push(M, read_packets_verify(R, SP, Trace, 0)); read_packets_verify(R, SP, [{trace,R,'send',{udp,R,{127,0,0,1},SP,_Msg}, Self} | Trace], M) when Self =:= self() -> read_packets_verify(R, SP, Trace, M+1); read_packets_verify(_R, _SP, [], M) -> push(M, []); read_packets_verify(_R, _SP, Trace, M) -> ct:fail({read_packets_verify,mismatch,Trace,M}). push(0, Vs) -> Vs; push(V, Vs) -> [V|Vs]. flush() -> receive X -> [X|flush()] after 200 -> [] end. %% Test that the 'fd' option works. open_fd(Config) when is_list(Config) -> Msg = "Det gör ont när knoppar brista. Varför skulle annars våren tveka?", Addr = {127,0,0,1}, {ok,S1} = gen_udp:open(0), {ok,P2} = inet:port(S1), {ok,FD} = prim_inet:getfd(S1), {error,einval} = gen_udp:open(0, [inet6, {fd,FD}]), {ok,S2} = gen_udp:open(0, [{fd,FD}]), {ok,S3} = gen_udp:open(0), {ok,P3} = inet:port(S3), ok = gen_udp:send(S3, Addr, P2, Msg), receive {udp,S2,Addr,P3,Msg} -> ok = gen_udp:send(S2,Addr,P3,Msg), receive {udp,S3,Addr,P2,Msg} -> ok after 1000 -> ct:fail(io_lib:format("~w", [flush()])) end after 1000 -> ct:fail(io_lib:format("~w", [flush()])) end. active_n(Config) when is_list(Config) -> N = 3, S1 = ok(gen_udp:open(0, [{active,N}])), [{active,N}] = ok(inet:getopts(S1, [active])), ok = inet:setopts(S1, [{active,-N}]), receive {udp_passive, S1} -> ok after 5000 -> exit({error,udp_passive_failure}) end, [{active,false}] = ok(inet:getopts(S1, [active])), ok = inet:setopts(S1, [{active,0}]), receive {udp_passive, S1} -> ok after 5000 -> exit({error,udp_passive_failure}) end, ok = inet:setopts(S1, [{active,32767}]), {error,einval} = inet:setopts(S1, [{active,1}]), {error,einval} = inet:setopts(S1, [{active,-32769}]), ok = inet:setopts(S1, [{active,-32768}]), receive {udp_passive, S1} -> ok after 5000 -> exit({error,udp_passive_failure}) end, [{active,false}] = ok(inet:getopts(S1, [active])), ok = inet:setopts(S1, [{active,N}]), ok = inet:setopts(S1, [{active,true}]), [{active,true}] = ok(inet:getopts(S1, [active])), receive _ -> exit({error,active_n}) after 0 -> ok end, ok = inet:setopts(S1, [{active,N}]), ok = inet:setopts(S1, [{active,once}]), [{active,once}] = ok(inet:getopts(S1, [active])), receive _ -> exit({error,active_n}) after 0 -> ok end, {error,einval} = inet:setopts(S1, [{active,32768}]), ok = inet:setopts(S1, [{active,false}]), [{active,false}] = ok(inet:getopts(S1, [active])), S1Port = ok(inet:port(S1)), S2 = ok(gen_udp:open(0, [{active,N}])), S2Port = ok(inet:port(S2)), [{active,N}] = ok(inet:getopts(S2, [active])), ok = inet:setopts(S1, [{active,N}]), [{active,N}] = ok(inet:getopts(S1, [active])), lists:foreach( fun(I) -> Msg = "message "++integer_to_list(I), ok = gen_udp:send(S2, "localhost", S1Port, Msg), receive {udp,S1,_,S2Port,Msg} -> ok = gen_udp:send(S1, "localhost", S2Port, Msg) after 5000 -> exit({error,timeout}) end, receive {udp,S2,_,S1Port,Msg} -> ok after 5000 -> exit({error,timeout}) end end, lists:seq(1,N)), receive {udp_passive,S1} -> [{active,false}] = ok(inet:getopts(S1, [active])) after 5000 -> exit({error,udp_passive}) end, receive {udp_passive,S2} -> [{active,false}] = ok(inet:getopts(S2, [active])) after 5000 -> exit({error,udp_passive}) end, S3 = ok(gen_udp:open(0, [{active,0}])), receive {udp_passive,S3} -> [{active,false}] = ok(inet:getopts(S3, [active])) after 5000 -> exit({error,udp_passive}) end, ok = gen_udp:close(S3), ok = gen_udp:close(S2), ok = gen_udp:close(S1), ok. local_basic(_Config) -> SFile = local_filename(server), SAddr = {local,bin_filename(SFile)}, CFile = local_filename(client), CAddr = {local,bin_filename(CFile)}, _ = file:delete(SFile), _ = file:delete(CFile), %% S = ok(gen_udp:open(0, [{ifaddr,{local,SFile}},{active,false}])), C = ok(gen_udp:open(0, [{ifaddr,{local,CFile}},{active,false}])), SAddr = ok(inet:sockname(S)), CAddr = ok(inet:sockname(C)), local_handshake(S, SAddr, C, CAddr), ok = gen_udp:close(S), ok = gen_udp:close(C), %% ok = file:delete(SFile), ok = file:delete(CFile), ok. local_unbound(_Config) -> SFile = local_filename(server), SAddr = {local,bin_filename(SFile)}, _ = file:delete(SFile), %% S = ok(gen_udp:open(0, [{ifaddr,SAddr},{active,false}])), C = ok(gen_udp:open(0, [local,{active,false}])), SAddr = ok(inet:sockname(S)), local_handshake(S, SAddr, C, undefined), ok = gen_udp:close(S), ok = gen_udp:close(C), %% ok = file:delete(SFile), ok. local_fdopen(_Config) -> SFile = local_filename(server), SAddr = {local,bin_filename(SFile)}, CFile = local_filename(client), CAddr = {local,bin_filename(CFile)}, _ = file:delete(SFile), _ = file:delete(CFile), %% S0 = ok(gen_udp:open(0, [{ifaddr,SAddr},{active,false}])), C = ok(gen_udp:open(0, [{ifaddr,{local,CFile}},{active,false}])), SAddr = ok(inet:sockname(S0)), CAddr = ok(inet:sockname(C)), Fd = ok(prim_inet:getfd(S0)), S = ok(gen_udp:open(0, [{fd,Fd},local,{active,false}])), SAddr = ok(inet:sockname(S)), local_handshake(S, SAddr, C, CAddr), ok = gen_udp:close(S), ok = gen_udp:close(S0), ok = gen_udp:close(C), %% ok = file:delete(SFile), ok = file:delete(CFile), ok. local_fdopen_unbound(_Config) -> SFile = local_filename(server), SAddr = {local,bin_filename(SFile)}, _ = file:delete(SFile), %% S = ok(gen_udp:open(0, [{ifaddr,SAddr},{active,false}])), C0 = ok(gen_udp:open(0, [local,{active,false}])), SAddr = ok(inet:sockname(S)), Fd = ok(prim_inet:getfd(C0)), C = ok(gen_udp:open(0, [{fd,Fd},local,{active,false}])), local_handshake(S, SAddr, C, undefined), ok = gen_udp:close(S), ok = gen_udp:close(C), ok = gen_udp:close(C0), %% ok = file:delete(SFile), ok. local_abstract(_Config) -> case os:type() of {unix,linux} -> S = ok(gen_udp:open(0, [{ifaddr,{local,<<>>}},{active,false}])), C = ok(gen_udp:open(0, [{ifaddr,{local,<<>>}},{active,false}])), {local,_} = SAddr = ok(inet:sockname(S)), {local,_} = CAddr = ok(inet:sockname(C)), local_handshake(S, SAddr, C, CAddr), ok = gen_udp:close(S), ok = gen_udp:close(C), ok; _ -> {skip,"AF_LOCAL Abstract Addresses only supported on Linux"} end. local_handshake(S, SAddr, C, CAddr) -> SData = "9876543210", CData = "0123456789", ok = gen_udp:send(C, SAddr, 0, CData), case ok(gen_tcp:recv(S, 112)) of {{unspec,<<>>}, 0, CData} when CAddr =:= undefined -> ok; {{local,<<>>}, 0, CData} when CAddr =:= undefined -> ok; {CAddr, 0, CData} when CAddr =/= undefined -> ok = gen_udp:send(S, CAddr, 0, SData), {SAddr, 0, SData} = ok(gen_tcp:recv(C, 112)), ok end. %% %% Utils %% start_node(Name) -> Pa = filename:dirname(code:which(?MODULE)), test_server:start_node(Name, slave, [{args, "-pa " ++ Pa}]). stop_node(Node) -> test_server:stop_node(Node). %% Test that connect/3 has effect. connect(Config) when is_list(Config) -> Addr = {127,0,0,1}, {ok,S1} = gen_udp:open(0), {ok,P1} = inet:port(S1), {ok,S2} = gen_udp:open(0), ok = inet:setopts(S2, [{active,false}]), ok = gen_udp:close(S1), ok = gen_udp:connect(S2, Addr, P1), ok = gen_udp:send(S2, <<16#deadbeef:32>>), ok = case gen_udp:recv(S2, 0, 500) of {error,econnrefused} -> ok; {error,econnreset} -> ok; Other -> Other end, ok. implicit_inet6(Config) when is_list(Config) -> Host = ok(inet:gethostname()), case inet:getaddr(Host, inet6) of {ok,Addr} -> implicit_inet6(Host, Addr); {error,Reason} -> {skip, "Can not look up IPv6 address: " ++atom_to_list(Reason)} end. implicit_inet6(Host, Addr) -> Active = {active,false}, Loopback = {0,0,0,0,0,0,0,1}, case gen_udp:open(0, [inet6,Active,{ip, Loopback}]) of {ok,S1} -> io:format("~s ~p~n", ["::1",Loopback]), implicit_inet6(S1, Active, Loopback), ok = gen_udp:close(S1), %% Localaddr = ok(get_localaddr()), S2 = ok(gen_udp:open(0, [{ip,Localaddr},Active])), implicit_inet6(S2, Active, Localaddr), ok = gen_udp:close(S2), %% io:format("~s ~p~n", [Host,Addr]), S3 = ok(gen_udp:open(0, [{ifaddr,Addr},Active])), implicit_inet6(S3, Active, Addr), ok = gen_udp:close(S3); _ -> {skip,"IPv6 not supported"} end. implicit_inet6(S1, Active, Addr) -> P1 = ok(inet:port(S1)), S2 = ok(gen_udp:open(0, [inet6,Active])), P2 = ok(inet:port(S2)), ok = gen_udp:connect(S2, Addr, P1), ok = gen_udp:connect(S1, Addr, P2), {Addr,P2} = ok(inet:peername(S1)), {Addr,P1} = ok(inet:peername(S2)), {Addr,P1} = ok(inet:sockname(S1)), {Addr,P2} = ok(inet:sockname(S2)), ok = gen_udp:send(S1, Addr, P2, "ping"), {Addr,P1,"ping"} = ok(gen_udp:recv(S2, 1024, 1000)), ok = gen_udp:send(S2, Addr, P1, "pong"), {Addr,P2,"pong"} = ok(gen_udp:recv(S1, 1024)), ok = gen_udp:close(S2). ok({ok,V}) -> V; ok(NotOk) -> try throw(not_ok) catch throw:Thrown:Stacktrace -> erlang:raise( error, {Thrown, NotOk}, tl(Stacktrace)) end. local_filename(Tag) -> "/tmp/" ?MODULE_STRING "_" ++ os:getpid() ++ "_" ++ atom_to_list(Tag). bin_filename(String) -> unicode:characters_to_binary(String, file:native_name_encoding()). delete_local_filenames() -> _ = [file:delete(F) || F <- filelib:wildcard( "/tmp/" ?MODULE_STRING "_" ++ os:getpid() ++ "_*")], ok. get_localaddr() -> get_localaddr(["localhost", "localhost6", "ip6-localhost"]). get_localaddr([]) -> {error, localaddr_not_found}; get_localaddr([Localhost|Ls]) -> case inet:getaddr(Localhost, inet6) of {ok, LocalAddr} -> io:format("~s ~p~n", [Localhost, LocalAddr]), {ok, LocalAddr}; _ -> get_localaddr(Ls) end.