diff options
Diffstat (limited to 'lib/kernel/test/gen_udp_SUITE.erl')
| -rw-r--r-- | lib/kernel/test/gen_udp_SUITE.erl | 439 |
1 files changed, 208 insertions, 231 deletions
diff --git a/lib/kernel/test/gen_udp_SUITE.erl b/lib/kernel/test/gen_udp_SUITE.erl index 8d8c953303..19cdc03603 100644 --- a/lib/kernel/test/gen_udp_SUITE.erl +++ b/lib/kernel/test/gen_udp_SUITE.erl @@ -17,17 +17,16 @@ %% %% %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("test_server/include/test_server.hrl"). +%% +%% 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"). --define(default_timeout, ?t:minutes(1)). -% XXX - we should pick a port that we _know_ is closed. That's pretty hard. +%% 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, @@ -38,7 +37,9 @@ buffer_size/1, binary_passive_recv/1, bad_address/1, read_packets/1, open_fd/1, connect/1, implicit_inet6/1]). -suite() -> [{ct_hooks,[ts_install_cth]}]. +suite() -> + [{ct_hooks,[ts_install_cth]}, + {timetrap,{minutes,1}}]. all() -> [send_to_closed, buffer_size, binary_passive_recv, @@ -62,28 +63,22 @@ end_per_group(_GroupName, Config) -> init_per_testcase(_Case, Config) -> - ?line Dog=test_server:timetrap(?default_timeout), - [{watchdog, Dog}|Config]. + Config. end_per_testcase(_Case, Config) -> - Dog=?config(watchdog, Config), - test_server:timetrap_cancel(Dog), ok. %%------------------------------------------------------------- %% Send two packets to a closed port (on some systems this causes the socket %% to be closed). -send_to_closed(doc) -> - ["Tests core functionality."]; -send_to_closed(suite) -> - []; +%% Tests core functionality. send_to_closed(Config) when is_list(Config) -> - ?line {ok, Sock} = gen_udp:open(0), - ?line ok = gen_udp:send(Sock, {127,0,0,1}, ?CLOSED_PORT, "foo"), + {ok, Sock} = gen_udp:open(0), + ok = gen_udp:send(Sock, {127,0,0,1}, ?CLOSED_PORT, "foo"), timer:sleep(2), - ?line ok = gen_udp:send(Sock, {127,0,0,1}, ?CLOSED_PORT, "foo"), - ?line ok = gen_udp:close(Sock), + ok = gen_udp:send(Sock, {127,0,0,1}, ?CLOSED_PORT, "foo"), + ok = gen_udp:close(Sock), ok. @@ -91,19 +86,16 @@ send_to_closed(Config) when is_list(Config) -> %%------------------------------------------------------------- %% Test that the UDP socket buffer sizes are settable -buffer_size(suite) -> - []; -buffer_size(doc) -> - ["Test UDP buffer size setting."]; +%% Test UDP buffer size setting. buffer_size(Config) when is_list(Config) -> - ?line Len = 256, - ?line Bin = list_to_binary(lists:seq(0, Len-1)), - ?line M = 8192 div Len, - ?line Spec0 = + 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}], - ?line Spec = + Spec = [case Tag of opt -> [{recbuf,Val*Len},{sndbuf,(Val + 2)*Len}]; @@ -115,12 +107,12 @@ buffer_size(Config) when is_list(Config) -> [truncated,emsgsize,timeout]} end || {Tag,Val} <- Spec0], %% - ?line {ok, ClientSocket} = gen_udp:open(0, [binary]), - ?line {ok, ClientPort} = inet:port(ClientSocket), - ?line Client = self(), - ?line ClientIP = {127,0,0,1}, - ?line ServerIP = {127,0,0,1}, - ?line Server = + {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]), @@ -130,78 +122,77 @@ buffer_size(Config) when is_list(Config) -> ServerSocket, 1, Spec), ok = gen_udp:close(ServerSocket) end), - ?line Mref = erlang:monitor(process, Server), - ?line receive - {Server,port,ServerPort} -> - ?line buffer_size_client(Server, ServerIP, ServerPort, - ClientSocket, 1, Spec) - end, - ?line ok = gen_udp:close(ClientSocket), - ?line receive - {'DOWN',Mref,_,_,normal} -> - ?line ok - 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(_, _, _, _, _, []) -> - ?line ok; + ok; buffer_size_client(Server, IP, Port, Socket, Cnt, [Opts|T]) when is_list(Opts) -> - ?line io:format("buffer_size_client Cnt=~w setopts ~p.~n", [Cnt,Opts]), - ?line ok = inet:setopts(Socket, Opts), - ?line Server ! {self(),setopts,Cnt}, - ?line receive {Server,setopts,Cnt} -> ok end, - ?line buffer_size_client(Server, IP, Port, Socket, Cnt+1, T); + 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) -> - ?line io:format( - "buffer_size_client Cnt=~w send size ~w expecting ~p.~n", - [Cnt,size(B),Replies]), - ?line ok = gen_udp:send(Socket, IP, Port, <<Cnt,B/binary>>), - ?line receive - {Server,Cnt,Reply} -> - ?line Tag = - if - is_tuple(Reply) -> - element(1, Reply); - is_atom(Reply) -> - Reply - end, - ?line case lists:member(Tag, Replies) of - true -> ok; - false -> - ?line - ?t:fail({reply_mismatch,Cnt,Reply,Replies, - byte_size(B), - inet:getopts(Socket, - [sndbuf,recbuf])}) - end, - ?line buffer_size_client(Server, IP, Port, Socket, Cnt+1, T) - after 1313 -> - ?line buffer_size_client(Server, IP, Port, Socket, Cnt, Opts) - end. + io:format( + "buffer_size_client Cnt=~w send size ~w expecting ~p.~n", + [Cnt,size(B),Replies]), + ok = gen_udp:send(Socket, IP, Port, <<Cnt,B/binary>>), + 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, - ?line io:format("buffer_size_server Cnt=~w setopts ~p.~n", [Cnt,Opts]), + 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) -> - ?line io:format( - "buffer_size_server Cnt=~w expecting size ~w.~n", - [Cnt,size(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), - ?line io:format( - "buffer_size_server Cnt=~w received size ~w.~n", - [Cnt,SizeD]), + io:format( + "buffer_size_server Cnt=~w received size ~w.~n", + [Cnt,SizeD]), case B of D -> correct; @@ -211,9 +202,9 @@ buffer_size_server(Client, IP, Port, {unexpected,D} end; Error -> - ?line io:format( - "buffer_size_server Cnt=~w received error ~w.~n", - [Cnt,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). @@ -236,50 +227,44 @@ buffer_size_server_recv(Socket, IP, Port, Cnt) -> %% OTP-3823 gen_udp:recv does not return address in binary mode %% -binary_passive_recv(suite) -> - []; -binary_passive_recv(doc) -> - ["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) -> - ?line D1 = "The quick brown fox jumps over a lazy dog", - ?line D2 = list_to_binary(D1), - ?line D3 = ["The quick", <<" brown ">>, "fox jumps ", <<"over ">>, - <<>>, $a, [[], " lazy ", <<"dog">>]], - ?line D2 = iolist_to_binary(D3), - ?line B = D2, - ?line {ok, R} = gen_udp:open(0, [binary, {active, false}]), - ?line {ok, RP} = inet:port(R), - ?line {ok, S} = gen_udp:open(0), - ?line {ok, SP} = inet:port(S), - ?line ok = gen_udp:send(S, localhost, RP, D1), - ?line {ok, {{127, 0, 0, 1}, SP, B}} = gen_udp:recv(R, byte_size(B)+1), - ?line ok = gen_udp:send(S, localhost, RP, D2), - ?line {ok, {{127, 0, 0, 1}, SP, B}} = gen_udp:recv(R, byte_size(B)+1), - ?line ok = gen_udp:send(S, localhost, RP, D3), - ?line {ok, {{127, 0, 0, 1}, SP, B}} = gen_udp:recv(R, byte_size(B)+1), - ?line ok = gen_udp:close(S), - ?line ok = gen_udp:close(R), + 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. -bad_address(suite) -> - []; -bad_address(doc) -> - ["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) -> - ?line {ok, R} = gen_udp:open(0), - ?line {ok, RP} = inet:port(R), - ?line {ok, S} = gen_udp:open(0), - ?line {ok, _SP} = inet:port(S), - ?line {'EXIT', badarg} = + {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")), - ?line {'EXIT', badarg} = + {'EXIT', badarg} = (catch gen_udp:send(S, {127,0,0,256}, RP, "void")), - ?line ok = gen_udp:close(S), - ?line ok = gen_udp:close(R), + ok = gen_udp:close(S), + ok = gen_udp:close(R), ok. @@ -298,8 +283,7 @@ bad_address(Config) when is_list(Config) -> %% What happens on the SMP emulator remains to be seen... %% -read_packets(doc) -> - ["OTP-6249 UDP option for number of packet reads."]; +%% OTP-6249 UDP option for number of packet reads. read_packets(Config) when is_list(Config) -> case erlang:system_info(smp_support) of false -> @@ -311,35 +295,35 @@ read_packets(Config) when is_list(Config) -> end. read_packets_1() -> - ?line N1 = 5, - ?line N2 = 7, - ?line {ok,R} = gen_udp:open(0, [{read_packets,N1}]), - ?line {ok,RP} = inet:port(R), - ?line {ok,Node} = start_node(gen_udp_SUITE_read_packets), - ?line Die = make_ref(), - ?line Loop = erlang:spawn_link(fun () -> infinite_loop(Die) end), + N1 = 5, + N2 = 7, + {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(), + Loop = erlang:spawn_link(fun () -> infinite_loop(Die) end), %% - ?line Msgs1 = [erlang:integer_to_list(M) || M <- lists:seq(1, N1*3)], - ?line [V1|_] = read_packets_test(R, RP, Msgs1, Node), - ?line {ok,[{read_packets,N1}]} = inet:getopts(R, [read_packets]), + Msgs1 = [erlang:integer_to_list(M) || M <- lists:seq(1, N1*3)], + [V1|_] = read_packets_test(R, RP, Msgs1, Node), + {ok,[{read_packets,N1}]} = inet:getopts(R, [read_packets]), %% - ?line ok = inet:setopts(R, [{read_packets,N2}]), - ?line Msgs2 = [erlang:integer_to_list(M) || M <- lists:seq(1, N2*3)], - ?line [V2|_] = read_packets_test(R, RP, Msgs2, Node), - ?line {ok,[{read_packets,N2}]} = inet:getopts(R, [read_packets]), + ok = inet:setopts(R, [{read_packets,N2}]), + Msgs2 = [erlang:integer_to_list(M) || M <- lists:seq(1, N2*3)], + [V2|_] = read_packets_test(R, RP, Msgs2, Node), + {ok,[{read_packets,N2}]} = inet:getopts(R, [read_packets]), %% - ?line stop_node(Node), - ?line Mref = erlang:monitor(process, Loop), - ?line Loop ! Die, - ?line receive - {'DOWN',Mref,_,_, normal} -> - case {V1,V2} of - {N1,N2} -> - ok; - _ when V1 =/= N1, V2 =/= N2 -> - ok - end - end. + stop_node(Node), + Mref = erlang:monitor(process, Loop), + Loop ! Die, + receive + {'DOWN',Mref,_,_, normal} -> + case {V1,V2} of + {N1,N2} -> + ok; + _ when V1 =/= N1, V2 =/= N2 -> + ok + end + end. infinite_loop(Die) -> receive @@ -407,21 +391,21 @@ read_packets_recv(N) -> read_packets_verify(R, SP, Msg, Trace) -> lists:reverse( - lists:sort(read_packets_verify(R, SP, Msg, Trace, 0))). - + lists:sort(read_packets_verify(R, SP, Msg, Trace, 0))). + read_packets_verify(R, SP, Msgs, [{trace,Self,OutIn,_}|Trace], M) when Self =:= self(), OutIn =:= out; Self =:= self(), OutIn =:= in -> push(M, read_packets_verify(R, SP, Msgs, Trace, 0)); read_packets_verify(R, SP, [Msg|Msgs], - [{trace,Self,'receive',{udp,R,{127,0,0,1},SP,Msg}} - |Trace], M) + [{trace,Self,'receive',{udp,R,{127,0,0,1},SP,Msg}} + |Trace], M) when Self =:= self() -> read_packets_verify(R, SP, Msgs, Trace, M+1); read_packets_verify(_R, _SP, [], [], M) -> push(M, []); read_packets_verify(_R, _SP, Msgs, Trace, M) -> - ?t:fail({read_packets_verify,mismatch,Msgs,Trace,M}). + ct:fail({read_packets_verify,mismatch,Msgs,Trace,M}). push(0, Vs) -> Vs; @@ -438,10 +422,7 @@ flush() -> -open_fd(suite) -> - []; -open_fd(doc) -> - ["Test that the 'fd' option works"]; +%% 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}, @@ -460,10 +441,10 @@ open_fd(Config) when is_list(Config) -> {udp,S3,Addr,P2,Msg} -> ok after 1000 -> - ?t:fail(io_lib:format("~w", [flush()])) + ct:fail(io_lib:format("~w", [flush()])) end after 1000 -> - ?t:fail(io_lib:format("~w", [flush()])) + ct:fail(io_lib:format("~w", [flush()])) end. active_n(Config) when is_list(Config) -> @@ -569,88 +550,84 @@ active_n(Config) when is_list(Config) -> ok = gen_udp:close(S1), ok. -% -% Utils -% +%% +%% Utils +%% + start_node(Name) -> Pa = filename:dirname(code:which(?MODULE)), - ?t:start_node(Name, slave, [{args, "-pa " ++ Pa}]). + test_server:start_node(Name, slave, [{args, "-pa " ++ Pa}]). stop_node(Node) -> - ?t:stop_node(Node). + test_server:stop_node(Node). -connect(suite) -> - []; -connect(doc) -> - ["Test that connect/3 has effect"]; +%% Test that connect/3 has effect. connect(Config) when is_list(Config) -> - ?line Addr = {127,0,0,1}, - ?line {ok,S1} = gen_udp:open(0), - ?line {ok,P1} = inet:port(S1), - ?line {ok,S2} = gen_udp:open(0), - ?line ok = inet:setopts(S2, [{active,false}]), - ?line ok = gen_udp:close(S1), - ?line ok = gen_udp:connect(S2, Addr, P1), - ?line ok = gen_udp:send(S2, <<16#deadbeef:32>>), - ?line ok = case gen_udp:recv(S2, 0, 5) of - {error,econnrefused} -> ok; - {error,econnreset} -> ok; - Other -> Other - end, + 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, 5) of + {error,econnrefused} -> ok; + {error,econnreset} -> ok; + Other -> Other + end, ok. implicit_inet6(Config) when is_list(Config) -> - ?line Host = ok(inet:gethostname()), - ?line - case inet:getaddr(Host, inet6) of - {ok,Addr} -> - ?line implicit_inet6(Host, Addr); - {error,Reason} -> - {skip, - "Can not look up IPv6 address: " - ++atom_to_list(Reason)} - end. + 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) -> - ?line Active = {active,false}, - ?line - case gen_udp:open(0, [inet6,Active]) of - {ok,S1} -> - ?line Loopback = {0,0,0,0,0,0,0,1}, - ?line io:format("~s ~p~n", ["::1",Loopback]), - ?line implicit_inet6(S1, Active, Loopback), - ?line ok = gen_udp:close(S1), - %% - ?line Localhost = "localhost", - ?line Localaddr = ok(inet:getaddr(Localhost, inet6)), - ?line io:format("~s ~p~n", [Localhost,Localaddr]), - ?line S2 = ok(gen_udp:open(0, [{ip,Localaddr},Active])), - ?line implicit_inet6(S2, Active, Localaddr), - ?line ok = gen_udp:close(S2), - %% - ?line io:format("~s ~p~n", [Host,Addr]), - ?line S3 = ok(gen_udp:open(0, [{ifaddr,Addr},Active])), - ?line implicit_inet6(S3, Active, Addr), - ?line ok = gen_udp:close(S3); - _ -> - {skip,"IPv6 not supported"} - end. + Active = {active,false}, + case gen_udp:open(0, [inet6,Active]) of + {ok,S1} -> + Loopback = {0,0,0,0,0,0,0,1}, + io:format("~s ~p~n", ["::1",Loopback]), + implicit_inet6(S1, Active, Loopback), + ok = gen_udp:close(S1), + %% + Localhost = "localhost", + Localaddr = ok(inet:getaddr(Localhost, inet6)), + io:format("~s ~p~n", [Localhost,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) -> - ?line P1 = ok(inet:port(S1)), - ?line S2 = ok(gen_udp:open(0, [inet6,Active])), - ?line P2 = ok(inet:port(S2)), - ?line ok = gen_udp:connect(S2, Addr, P1), - ?line ok = gen_udp:connect(S1, Addr, P2), - ?line {Addr,P2} = ok(inet:peername(S1)), - ?line {Addr,P1} = ok(inet:peername(S2)), - ?line {Addr,P1} = ok(inet:sockname(S1)), - ?line {Addr,P2} = ok(inet:sockname(S2)), - ?line ok = gen_udp:send(S1, Addr, P2, "ping"), - ?line {Addr,P1,"ping"} = ok(gen_udp:recv(S2, 1024, 1000)), - ?line ok = gen_udp:send(S2, Addr, P1, "pong"), - ?line {Addr,P2,"pong"} = ok(gen_udp:recv(S1, 1024)), - ?line ok = gen_udp:close(S2). + 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. |