diff options
Diffstat (limited to 'lib/diameter/src/transport/diameter_sctp.erl')
| -rw-r--r-- | lib/diameter/src/transport/diameter_sctp.erl | 476 |
1 files changed, 220 insertions, 256 deletions
diff --git a/lib/diameter/src/transport/diameter_sctp.erl b/lib/diameter/src/transport/diameter_sctp.erl index 49a530b4eb..4a005b853d 100644 --- a/lib/diameter/src/transport/diameter_sctp.erl +++ b/lib/diameter/src/transport/diameter_sctp.erl @@ -1,24 +1,24 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 2010-2013. All Rights Reserved. +%% Copyright Ericsson AB 2010-2016. All Rights Reserved. %% -%% The contents of this file are subject to the Erlang Public License, -%% Version 1.1, (the "License"); you may not use this file except in -%% compliance with the License. You should have received a copy of the -%% Erlang Public License along with this software. If not, it can be -%% retrieved online at http://www.erlang.org/. +%% 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 %% -%% Software distributed under the License is distributed on an "AS IS" -%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See -%% the License for the specific language governing rights and limitations -%% under the License. +%% 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% %% -module(diameter_sctp). - -behaviour(gen_server). %% interface @@ -37,7 +37,8 @@ code_change/3, terminate/2]). --export([info/1]). %% service_info callback +-export([listener/1,%% diameter_sync callback + info/1]). %% service_info callback -export([ports/0, ports/1]). @@ -60,61 +61,62 @@ %% Remote addresses to accept connections from. -define(DEFAULT_ACCEPT, []). %% any -%% How long a listener with no associations lives before offing -%% itself. --define(LISTENER_TIMEOUT, 30000). - %% How long to wait for a transport process to attach after %% association establishment. -define(ACCEPT_TIMEOUT, 5000). -type connect_option() :: {raddr, inet:ip_address()} | {rport, inet:port_number()} - | gen_sctp:open_option(). + | term(). %% gen_sctp:open_option(). -type match() :: inet:ip_address() | string() | [match()]. -type listen_option() :: {accept, match()} - | gen_sctp:open_option(). + | term(). %% gen_sctp:open_option(). -type uint() :: non_neg_integer(). %% Accepting/connecting transport process state. -record(transport, - {parent :: pid(), + {parent :: pid() | undefined, mode :: {accept, pid()} | accept | {connect, {[inet:ip_address()], uint(), list()}} %% {RAs, RP, Errors} | connect, - socket :: gen_sctp:sctp_socket(), + socket :: gen_sctp:sctp_socket() | undefined, assoc_id :: gen_sctp:assoc_id(), %% association identifier - peer :: {[inet:ip_address()], uint()}, %% {RAs, RP} - streams :: {uint(), uint()}, %% {InStream, OutStream} counts + peer :: {[inet:ip_address()], uint()} %% {RAs, RP} + | undefined, + streams :: {uint(), uint()} %% {InStream, OutStream} counts + | undefined, os = 0 :: uint()}). %% next output stream %% Listener process state. -record(listener, {ref :: reference(), socket :: gen_sctp:sctp_socket(), - count = 0 :: uint(), - tmap = ets:new(?MODULE, []) :: ets:tid(), - %% {MRef, Pid|AssocId}, {AssocId, Pid} - pending = {0, ets:new(?MODULE, [ordered_set])}, - tref :: reference(), + count = 0 :: uint(), %% attached transport processes + pending = {0, queue:new()}, accept :: [match()]}). -%% Field tmap is used to map an incoming message or event to the -%% relevent transport process. Field pending implements a queue of -%% transport processes to which an association has been assigned (at -%% comm_up and written into tmap) but for which diameter hasn't yet -%% spawned a transport process: a short-lived state of affairs as a -%% new transport is spawned as a consequence of a peer being taken up, -%% transport processes being spawned by the listener on demand. In -%% case diameter starts a transport before comm_up on a new -%% association, pending is set to an improper list with the spawned -%% transport as head and the queue as tail. +%% Field pending implements two queues: the first of transport-to-be +%% processes to which an association has been assigned but for which +%% diameter hasn't yet spawned a transport process, a short-lived +%% state of affairs as a new transport is spawned as a consequence of +%% a peer being taken up, transport processes being spawned by the +%% listener on demand; the second of started transport processes that +%% have not yet been assigned an association. +%% +%% When diameter calls start/3, the transport process is either taken +%% from the first queue or spawned and placed in the second queue +%% until an association is established. When an association is +%% established, a controlling process is either taken from the second +%% queue or spawned and placed in the first queue. Thus, there are +%% only elements in one queue at a time, so share an ets table queue +%% and tag it with a positive length if it contains the first queue, a +%% negative length if it contains the second queue. %% --------------------------------------------------------------------------- %% # start/3 @@ -139,9 +141,9 @@ ip(T) -> T. %% A listener spawns transports either as a consequence of this call -%% when there is not yet an association to associate with it, or at -%% comm_up on a new association in which case the call retrieves a -%% transport from the pending queue. +%% when there is not yet an association to assign it, or at comm_up on +%% a new association in which case the call retrieves a transport from +%% the pending queue. s({accept, Ref} = A, Addrs, Opts) -> {LPid, LAs} = listener(Ref, {Opts, Addrs}), try gen_server:call(LPid, {A, self()}, infinity) of @@ -171,18 +173,33 @@ start_link(T) -> info({gen_sctp, Sock}) -> lists:flatmap(fun(K) -> info(K, Sock) end, - [{socket, sockname}, - {peer, peername}, + [{socket, socknames}, + {peer, peernames}, {statistics, getstat}]). info({K,F}, Sock) -> case inet:F(Sock) of {ok, V} -> - [{K,V}]; + [{K, map(F,V)}]; _ -> [] end. +%% inet:{sock,peer}names/1 returns [{Addr, Port}] but the port number +%% should be the same in each tuple. Map to a {[Addr], Port} tuple if +%% so. +map(K, [{_, Port} | _] = APs) + when K == socknames; + K == peernames -> + try [A || {A,P} <- APs, P == Port orelse throw(?MODULE)] of + As -> {As, Port} + catch + ?MODULE -> APs + end; + +map(_, V) -> + V. + %% --------------------------------------------------------------------------- %% # init/1 %% --------------------------------------------------------------------------- @@ -194,14 +211,15 @@ init(T) -> %% A process owning a listening socket. i({listen, Ref, {Opts, Addrs}}) -> + [_] = diameter_config:subscribe(Ref, transport), %% assert existence {[Matches], Rest} = proplists:split(Opts, [accept]), {LAs, Sock} = AS = open(Addrs, Rest, ?DEFAULT_PORT), - proc_lib:init_ack({ok, self(), LAs}), ok = gen_sctp:listen(Sock, true), true = diameter_reg:add_new({?MODULE, listener, {Ref, AS}}), - start_timer(#listener{ref = Ref, - socket = Sock, - accept = accept(Matches)}); + proc_lib:init_ack({ok, self(), LAs}), + #listener{ref = Ref, + socket = Sock, + accept = [[M] || {accept, M} <- Matches]}; %% A connecting transport. i({connect, Pid, Opts, Addrs, Ref}) -> @@ -211,59 +229,73 @@ i({connect, Pid, Opts, Addrs, Ref}) -> {LAs, Sock} = open(Addrs, Rest, 0), putr(?REF_KEY, Ref), proc_lib:init_ack({ok, self(), LAs}), - erlang:monitor(process, Pid), + monitor(process, Pid), #transport{parent = Pid, mode = {connect, connect(Sock, RAs, RP, [])}, socket = Sock}; -%% An accepting transport spawned by diameter. -i({accept, Pid, LPid, Sock, Ref}) +%% An accepting transport spawned by diameter, not yet owning an +%% association. +i({accept, Ref, LPid, Pid}) when is_pid(Pid) -> putr(?REF_KEY, Ref), proc_lib:init_ack({ok, self()}), - erlang:monitor(process, Pid), - erlang:monitor(process, LPid), - #transport{parent = Pid, - mode = {accept, LPid}, - socket = Sock}; - -%% An accepting transport spawned at association establishment. -i({accept, Ref, LPid, Sock, Id}) -> + monitor(process, Pid), + MRef = monitor(process, LPid), + wait([{peeloff, MRef}], #transport{parent = Pid, + mode = {accept, LPid}}); + +%% An accepting transport spawned at association establishment, whose +%% parent is not yet known. +i({accept, Ref, LPid}) -> putr(?REF_KEY, Ref), proc_lib:init_ack({ok, self()}), - MRef = erlang:monitor(process, LPid), - %% Wait for a signal that the transport has been started before - %% processing other messages. + erlang:send_after(?ACCEPT_TIMEOUT, self(), accept_timeout), + MRef = monitor(process, LPid), + wait([{parent, Ref}, {peeloff, MRef}], #transport{mode = {accept, LPid}}). + +%% wait/2 +%% +%% Wait for diameter to start the transport process and for the +%% association to be peeled off before processing other messages. + +wait(Keys, S) -> + lists:foldl(fun i/2, S, Keys). + +i({K, Ref}, #transport{mode = {accept, _}} = S) -> receive - {Ref, Pid} -> %% transport started - #transport{parent = Pid, - mode = {accept, LPid}, - socket = Sock}; - {'DOWN', MRef, process, _, _} = T -> %% listener down - close(Sock, Id), + {Ref, Pid} when K == parent -> %% transport process started + S#transport{parent = Pid}; + {K, T, Matches} when K == peeloff -> %% association + {sctp, Sock, _RA, _RP, _Data} = T, + ok = accept_peer(Sock, Matches), + demonitor(Ref, [flush]), + t(T, S#transport{socket = Sock}); + accept_timeout = T -> + x(T); + {'DOWN', _, process, _, _} = T -> x(T) - after ?ACCEPT_TIMEOUT -> - close(Sock, Id), - x(timeout) end. -%% close/2 - -close(Sock, Id) -> - gen_sctp:eof(Sock, #sctp_assoc_change{assoc_id = Id}). -%% Having to pass a record here is hokey. - %% listener/2 +%% Accepting processes can be started concurrently: ensure only one +%% listener is started. listener(LRef, T) -> + diameter_sync:call({?MODULE, listener, LRef}, + {?MODULE, listener, [{LRef, T}]}, + infinity, + infinity). + +listener({LRef, T}) -> l(diameter_reg:match({?MODULE, listener, {LRef, '_'}}), LRef, T). -%% Existing process with the listening socket ... +%% Existing listening process ... l([{{?MODULE, listener, {_, AS}}, LPid}], _, _) -> - {LAs, _Sock} = AS, - {LPid, LAs}; + {LAs, _Sock} = AS, + {LPid, LAs}; -%% ... or not: start one. +%% ... or not. l([], LRef, T) -> {ok, LPid, LAs} = diameter_sctp_sup:start_child({listen, LRef, T}), {LPid, LAs}. @@ -333,13 +365,10 @@ type(T) -> %% --------------------------------------------------------------------------- handle_call({{accept, Ref}, Pid}, _, #listener{ref = Ref, - count = N} + count = K} = S) -> {TPid, NewS} = accept(Ref, Pid, S), - {reply, {ok, TPid}, NewS#listener{count = N+1}}; - -handle_call(T, From, {listener,_,_,_,_,_,_} = S) -> % started in old code - handle_call(T, From, upgrade(S)); + {reply, {ok, TPid}, NewS#listener{count = K+1}}; handle_call(_, _, State) -> {reply, nok, State}. @@ -359,10 +388,16 @@ handle_info(T, #transport{} = S) -> {noreply, #transport{} = t(T,S)}; handle_info(T, #listener{} = S) -> - {noreply, #listener{} = l(T,S)}; + {noreply, #listener{} = l(T,S)}. -handle_info(T, {listener,_,_,_,_,_,_} = S) -> % started in old code - handle_info(T, upgrade(S)). +%% Prior to the possiblity of setting pool_size on in transport +%% configuration, a new accepting transport was only started following +%% the death of a predecessor, so that there was only at most one +%% previously started transport process waiting for an association. +%% This assumption no longer holds with pool_size > 1, in which case +%% several accepting transports are started concurrently. Deal with +%% this by placing the started transports in a new queue of transport +%% processes waiting for an association. %% --------------------------------------------------------------------------- %% # code_change/3 @@ -378,16 +413,6 @@ code_change(_, State, _) -> terminate(_, #transport{assoc_id = undefined}) -> ok; -terminate(_, #transport{socket = Sock, - mode = accept, - assoc_id = Id}) -> - close(Sock, Id); - -terminate(_, #transport{socket = Sock, - mode = {accept, _}, - assoc_id = Id}) -> - close(Sock, Id); - terminate(_, #transport{socket = Sock}) -> gen_sctp:close(Sock); @@ -396,88 +421,53 @@ terminate(_, #listener{socket = Sock}) -> %% --------------------------------------------------------------------------- -upgrade(S) -> - #listener{} = erlang:append_element(S, ?DEFAULT_ACCEPT). - putr(Key, Val) -> put({?MODULE, Key}, Val). getr(Key) -> get({?MODULE, Key}). -%% start_timer/1 - -start_timer(#listener{count = 0} = S) -> - S#listener{tref = erlang:start_timer(?LISTENER_TIMEOUT, self(), close)}; -start_timer(S) -> - S. - %% l/2 %% %% Transition listener state. %% Incoming message from SCTP. -l({sctp, Sock, _RA, _RP, Data} = Msg, #listener{socket = Sock} = S) -> +l({sctp, Sock, _RA, _RP, Data} = T, #listener{socket = Sock, + accept = Matches} + = S) -> Id = assoc_id(Data), + {TPid, NewS} = accept(S), + TPid ! {peeloff, setelement(2, T, peeloff(Sock, Id, TPid)), Matches}, + setopts(Sock), + NewS; - try find(Id, Data, S) of - {TPid, NewS} -> - TPid ! {peeloff, peeloff(Sock, Id, TPid), Msg, S#listener.accept}, - NewS; - false -> - S - after - setopts(Sock) - end; +l({'DOWN', _MRef, process, TPid, _}, #listener{pending = {_,Q}} = S) -> + down(queue:member(TPid, Q), TPid, S); -%% Transport is asking message to be sent. See send/3 for why the send -%% isn't directly from the transport. -l({send, AssocId, StreamId, Bin}, #listener{socket = Sock} = S) -> - send(Sock, AssocId, StreamId, Bin), - S; +%% Transport has been removed. +l({transport, remove, _} = T, #listener{socket = Sock}) -> + gen_sctp:close(Sock), + x(T). -%% Accepting transport has died. One that's awaiting an association ... -l({'DOWN', MRef, process, TPid, _}, #listener{pending = [TPid | Q], - tmap = T, - count = N} - = S) -> - ets:delete(T, MRef), - ets:delete(T, TPid), - start_timer(S#listener{count = N-1, - pending = Q}); - -%% ... ditto and a new transport has already been started ... -l({'DOWN', _, process, _, _} = T, #listener{pending = [TPid | Q]} - = S) -> - #listener{pending = NQ} - = NewS - = l(T, S#listener{pending = Q}), - NewS#listener{pending = [TPid | NQ]}; +%% down/3 +%% +%% Accepting transport has died. -%% ... or not. -l({'DOWN', MRef, process, TPid, _}, #listener{socket = Sock, - tmap = T, - count = N, - pending = {P,Q}} - = S) -> - [{MRef, Id}] = ets:lookup(T, MRef), %% Id = TPid | AssocId - ets:delete(T, MRef), - ets:delete(T, Id), - Id == TPid orelse close(Sock, Id), - case ets:lookup(Q, TPid) of - [{TPid, _}] -> %% transport in the pending queue ... - ets:delete(Q, TPid), - S#listener{pending = {P-1, Q}}; - [] -> %% ... or not - start_timer(S#listener{count = N-1}) +%% One that's waiting for transport start in the pending queue ... +down(true, TPid, #listener{pending = {N,Q}, + count = K} + = S) -> + NQ = queue:filter(fun(P) -> P /= TPid end, Q), + if N < 0 -> %% awaiting an association ... + S#listener{count = K-1, + pending = {N+1, NQ}}; + true -> %% ... or one has been assigned + S#listener{pending = {N-1, NQ}} end; -%% Timeout after the last accepting process has died. -l({timeout, TRef, close = T}, #listener{tref = TRef, - count = 0}) -> - x(T); -l({timeout, _, close}, #listener{} = S) -> - S. +%% ... or one that's already attached. +down(false, _TPid, #listener{count = K} = S) -> + S#listener{count = K-1}. %% t/2 %% @@ -495,22 +485,10 @@ t(T,S) -> %% transition/2 -%% Listening process is transfering ownership of an association. -transition({peeloff, Sock, {sctp, LSock, _RA, _RP, _Data} = Msg, Matches}, - #transport{mode = {accept, _}, - socket = LSock} - = S) -> - ok = accept_peer(Sock, Matches), - transition(Msg, S#transport{socket = Sock}); -transition({peeloff = T, _Sock, _Msg} = T, #transport{} = S) ->% from old code - transition(erlang:append_element(T, ?DEFAULT_ACCEPT), S); - %% Incoming message. -transition({sctp, _Sock, _RA, _RP, Data}, #transport{socket = Sock} = S) -> +transition({sctp, Sock, _RA, _RP, Data}, #transport{socket = Sock} = S) -> setopts(Sock), recv(Data, S); -%% Don't match on Sock since in R15B01 it can be the listening socket -%% in the (peeled-off) accept case, which is likely a bug. %% Outgoing message. transition({diameter, {send, Msg}}, S) -> @@ -532,13 +510,8 @@ transition({diameter, {tls, _Ref, _Type, _Bool}}, _) -> transition({'DOWN', _, process, Pid, _}, #transport{parent = Pid}) -> stop; -%% Listener process has died. -transition({'DOWN', _, process, Pid, _}, #transport{mode = {accept, Pid}}) -> - stop; - -%% Ditto but we have ownership of the association. It might be that -%% we'll go down anyway though. -transition({'DOWN', _, process, _Pid, _}, #transport{mode = accept}) -> +%% Timeout after transport process has been started. +transition(accept_timeout, _) -> ok; %% Request for the local port number. @@ -560,56 +533,45 @@ accept_peer(_, []) -> ok; accept_peer(Sock, Matches) -> - {RAddrs, _} = ok(inet:peername(Sock)), + RAddrs = [A || {A,_} <- ok(inet:peernames(Sock))], diameter_peer:match(RAddrs, Matches) orelse x({accept, RAddrs, Matches}), ok. -%% accept/1 - -accept(Opts) -> - [[M] || {accept, M} <- Opts]. - %% accept/3 %% %% Start a new transport process or use one that's already been -%% started as a consequence of association establishment. +%% started as a consequence of diameter requesting a transport +%% process. -%% No pending associations: spawn a new transport. -accept(Ref, Pid, #listener{socket = Sock, - tmap = T, - pending = {0,_} = Q} - = S) -> - Arg = {accept, Pid, self(), Sock, Ref}, - {ok, TPid} = diameter_sctp_sup:start_child(Arg), - MRef = erlang:monitor(process, TPid), - ets:insert(T, [{MRef, TPid}, {TPid, MRef}]), - {TPid, S#listener{pending = [TPid | Q]}}; -%% Placing the transport in the pending field makes it available to -%% the next association. The stack starts a new accepting transport -%% only after this one brings the connection up (or dies). - -%% Accepting transport has died. This can happen if a new transport is -%% started before the DOWN has arrived. -accept(Ref, Pid, #listener{pending = [TPid | {0,_} = Q]} = S) -> - false = is_process_alive(TPid), %% assert - accept(Ref, Pid, S#listener{pending = Q}); +accept(Ref, Pid, #listener{pending = {N,_}} = S) -> + {TPid, NQ} = q(Ref, Pid, S), + {TPid, S#listener{pending = {N-1, NQ}}}. %% Pending associations: attach to the first in the queue. -accept(_, Pid, #listener{ref = Ref, pending = {N,Q}} = S) -> - TPid = ets:first(Q), +q(_, Pid, #listener{ref = Ref, + pending = {N,Q}}) + when 0 < N -> + {TPid, _} = T = dq(Q), TPid ! {Ref, Pid}, - ets:delete(Q, TPid), - {TPid, S#listener{pending = {N-1, Q}}}. + T; + +%% No pending associations: spawn a new transport. +q(Ref, Pid, #listener{pending = {_,Q}}) -> + nq({accept, Ref, self(), Pid}, Q). %% send/2 %% Outbound Diameter message on a specified stream ... -send(#diameter_packet{bin = Bin, transport_data = {stream, SId}}, S) -> - send(SId, Bin, S), +send(#diameter_packet{bin = Bin, transport_data = {outstream, SId}}, + #transport{streams = {_, OS}} + = S) -> + send(SId rem OS, Bin, S), S; -%% ... or not: rotate through all steams. +%% ... or not: rotate through all streams. +send(#diameter_packet{bin = Bin}, S) -> + send(Bin, S); send(Bin, #transport{streams = {_, OS}, os = N} = S) @@ -657,7 +619,7 @@ recv({_, #sctp_assoc_change{} = E}, = S) -> S#transport{mode = {C, connect(Sock, RAs, RP, [{RA,E} | Es])}}; -%% Lost association after establishment. +%% Association failure. recv({_, #sctp_assoc_change{}}, _) -> stop; @@ -668,8 +630,10 @@ recv({[#sctp_sndrcvinfo{stream = Id}], Bin}, #transport{parent = Pid}) bin = Bin}), ok; -recv({_, #sctp_shutdown_event{assoc_id = Id}}, - #transport{assoc_id = Id}) -> +recv({_, #sctp_shutdown_event{assoc_id = A}}, + #transport{assoc_id = Id}) + when A == Id; + A == 0 -> stop; %% Note that diameter_sctp(3) documents that sctp_events cannot be @@ -705,49 +669,49 @@ up(#transport{parent = Pid, diameter_peer:up(Pid), S#transport{mode = A}. -%% find/3 - -find(Id, Data, #listener{tmap = T} = S) -> - f(ets:lookup(T, Id), Data, S). - -%% New association and a transport waiting for one: use it. -f([], - {_, #sctp_assoc_change{state = comm_up, - assoc_id = Id}}, - #listener{tmap = T, - pending = [TPid | {_,_} = Q]} - = S) -> - [{TPid, MRef}] = ets:lookup(T, TPid), - ets:insert(T, [{MRef, Id}, {Id, TPid}]), - ets:delete(T, TPid), - {TPid, S#listener{pending = Q}}; - -%% New association and no transport start yet: spawn one and place it -%% in the queue. -f([], - {_, #sctp_assoc_change{state = comm_up, - assoc_id = Id}}, - #listener{ref = Ref, - socket = Sock, - tmap = T, - pending = {N,Q}} - = S) -> - Arg = {accept, Ref, self(), Sock, Id}, +%% accept/1 +%% +%% Start a new transport process or use one that's already been +%% started as a consequence of an event to a listener process. + +accept(#listener{pending = {N,_}} = S) -> + {TPid, NQ} = q(S), + {TPid, S#listener{pending = {N+1, NQ}}}. + +%% Transport waiting for an association: use it. +q(#listener{pending = {N,Q}}) + when N < 0 -> + dq(Q); + +%% No transport start yet: spawn one and queue. +q(#listener{ref = Ref, + pending = {_,Q}}) -> + nq({accept, Ref, self()}, Q). + +%% nq/2 +%% +%% Place a transport process in the second pending queue to make it +%% available to the next association. + +nq(Arg, Q) -> {ok, TPid} = diameter_sctp_sup:start_child(Arg), - MRef = erlang:monitor(process, TPid), - ets:insert(T, [{MRef, Id}, {Id, TPid}]), - ets:insert(Q, {TPid, now()}), - {TPid, S#listener{pending = {N+1, Q}}}; + monitor(process, TPid), + {TPid, queue:in(TPid, Q)}. -%% Known association ... -f([{_, TPid}], _, S) -> - {TPid, S}; +%% dq/1 +%% +%% Remove a transport process from the first pending queue to assign +%% it to an existing association. -%% ... or not: discard. -f([], _, _) -> - false. +dq(Q) -> + {{value, TPid}, NQ} = queue:out(Q), + {TPid, NQ}. %% assoc_id/1 +%% +%% It's unclear if this is needed, or if the first message on an +%% association is always sctp_assoc_change, but don't assume since +%% SCTP behaviour differs between operating systems. assoc_id({[#sctp_sndrcvinfo{assoc_id = Id}], _}) -> Id; |