SCTP Examples
Example of an Erlang SCTP server that receives SCTP messages and prints them on the standard output:
-module(sctp_server).
-export([server/0,server/1,server/2]).
-include_lib("kernel/include/inet.hrl").
-include_lib("kernel/include/inet_sctp.hrl").
server() ->
server(any, 2006).
server([Host,Port]) when is_list(Host), is_list(Port) ->
{ok, #hostent{h_addr_list = [IP|_]}} = inet:gethostbyname(Host),
io:format("~w -> ~w~n", [Host, IP]),
server([IP, list_to_integer(Port)]).
server(IP, Port) when is_tuple(IP) orelse IP == any orelse IP == loopback,
is_integer(Port) ->
{ok,S} = gen_sctp:open(Port, [{recbuf,65536}, {ip,IP}]),
io:format("Listening on ~w:~w. ~w~n", [IP,Port,S]),
ok = gen_sctp:listen(S, true),
server_loop(S).
server_loop(S) ->
case gen_sctp:recv(S) of
{error, Error} ->
io:format("SCTP RECV ERROR: ~p~n", [Error]);
Data ->
io:format("Received: ~p~n", [Data])
end,
server_loop(S).
Example of an Erlang SCTP client interacting with the above server. Notice that in this example the client creates an association with the server with 5 outbound streams. Therefore, sending of "Test 0"
over stream 0 succeeds, but sending of "Test 5"
over stream 5 fails. The client then abort
s the association, which results in that the corresponding event is received on the server side.
-module(sctp_client).
-export([client/0, client/1, client/2]).
-include_lib("kernel/include/inet.hrl").
-include_lib("kernel/include/inet_sctp.hrl").
client() ->
client([localhost]).
client([Host]) ->
client(Host, 2006);
client([Host, Port]) when is_list(Host), is_list(Port) ->
client(Host,list_to_integer(Port)),
init:stop().
client(Host, Port) when is_integer(Port) ->
{ok,S} = gen_sctp:open(),
{ok,Assoc} = gen_sctp:connect
(S, Host, Port, [{sctp_initmsg,#sctp_initmsg{num_ostreams=5}}]),
io:format("Connection Successful, Assoc=~p~n", [Assoc]),
io:write(gen_sctp:send(S, Assoc, 0, <<"Test 0">>)),
io:nl(),
timer:sleep(10000),
io:write(gen_sctp:send(S, Assoc, 5, <<"Test 5">>)),
io:nl(),
timer:sleep(10000),
io:write(gen_sctp:abort(S, Assoc)),
io:nl(),
timer:sleep(1000),
gen_sctp:close(S).
A simple Erlang SCTP client that uses the connect_init
API:
-module(ex3).
-export([client/4]).
-include_lib("kernel/include/inet.hrl").
-include_lib("kernel/include/inet_sctp.hrl").
client(Peer1, Port1, Peer2, Port2)
when is_tuple(Peer1), is_integer(Port1), is_tuple(Peer2), is_integer(Port2) ->
{ok,S} = gen_sctp:open(),
SctpInitMsgOpt = {sctp_initmsg,#sctp_initmsg{num_ostreams=5}},
ActiveOpt = {active, true},
Opts = [SctpInitMsgOpt, ActiveOpt],
ok = gen_sctp:connect(S, Peer1, Port1, Opts),
ok = gen_sctp:connect(S, Peer2, Port2, Opts),
io:format("Connections initiated~n", []),
client_loop(S, Peer1, Port1, undefined, Peer2, Port2, undefined).
client_loop(S, Peer1, Port1, AssocId1, Peer2, Port2, AssocId2) ->
receive
{sctp, S, Peer1, Port1, {_Anc, SAC}}
when is_record(SAC, sctp_assoc_change), AssocId1 == undefined ->
io:format("Association 1 connect result: ~p. AssocId: ~p~n",
[SAC#sctp_assoc_change.state,
SAC#sctp_assoc_change.assoc_id]),
client_loop(S, Peer1, Port1, SAC#sctp_assoc_change.assoc_id,
Peer2, Port2, AssocId2);
{sctp, S, Peer2, Port2, {_Anc, SAC}}
when is_record(SAC, sctp_assoc_change), AssocId2 == undefined ->
io:format("Association 2 connect result: ~p. AssocId: ~p~n",
[SAC#sctp_assoc_change.state, SAC#sctp_assoc_change.assoc_id]),
client_loop(S, Peer1, Port1, AssocId1, Peer2, Port2,
SAC#sctp_assoc_change.assoc_id);
{sctp, S, Peer1, Port1, Data} ->
io:format("Association 1: received ~p~n", [Data]),
client_loop(S, Peer1, Port1, AssocId1,
Peer2, Port2, AssocId2);
{sctp, S, Peer2, Port2, Data} ->
io:format("Association 2: received ~p~n", [Data]),
client_loop(S, Peer1, Port1, AssocId1,
Peer2, Port2, AssocId2);
Other ->
io:format("Other ~p~n", [Other]),
client_loop(S, Peer1, Port1, AssocId1,
Peer2, Port2, AssocId2)
after 5000 ->
ok
end.