Schedule pokes of registered SIP peers within a given timespan after SIP reload

With a large number of SIP peers registered, performing a SIP reload causes a
flood of SIP OPTIONS request packets.  These are immediately sent out, and, as
responses come back, can cause peers to be flagged as 'lagged' due to handling
of the many response messages.

This fix prevents this "packet storm" and schedules the pokes for a random
time.  That time varies between 1 ms and the peer's qualify time, or, if
the qualify time is unknown, the global qualifyfreq setting.

The committed patch has some very small modifications to the patch schmidts
wrote for the review.

(closes issue ASTERISK-19154)
Reported by: Nicolo Mazzon
patches:
  issue19154.patch license #6034 uploaded by schmidts

Review: https://reviewboard.asterisk.org/r/1652




git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@370666 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -13942,14 +13942,14 @@ static void reg_source_db(struct sip_peer *peer)
 	    peer->name, peer->username, ast_sockaddr_stringify_host(&sa), expire);
 
 	ast_sockaddr_copy(&peer->addr, &sa);
-	if (sipsock < 0) {
-		/* SIP isn't up yet, so schedule a poke only, pretty soon */
-		AST_SCHED_REPLACE_UNREF(peer->pokeexpire, sched, ast_random() % 5000 + 1, sip_poke_peer_s, peer,
+	if (peer->maxms) {
+		/* Don't poke peer immediately, just schedule it within qualifyfreq */
+		AST_SCHED_REPLACE_UNREF(peer->pokeexpire, sched,
+				ast_random() % ((peer->qualifyfreq) ? peer->qualifyfreq : global_qualifyfreq) + 1,
+				sip_poke_peer_s, peer,
 				unref_peer(_data, "removing poke peer ref"),
 				unref_peer(peer, "removing poke peer ref"),
 				ref_peer(peer, "adding poke peer ref"));
-	} else {
-		sip_poke_peer(peer, 0);
 	}
 	AST_SCHED_REPLACE_UNREF(peer->expire, sched, (expire + 10) * 1000, expire_register, peer,
 			unref_peer(_data, "remove registration ref"),
@@ -29807,16 +29807,19 @@ static void sip_poke_all_peers(void)
 	i = ao2_iterator_init(peers, 0);
 	while ((peer = ao2_t_iterator_next(&i, "iterate thru peers table"))) {
 		ao2_lock(peer);
-		if (num == global_qualify_peers) {
-			ms += global_qualify_gap;
-			num = 0;
-		} else {
-			num++;
+		/* Don't schedule poking on a peer without qualify */
+		if (peer->maxms) {
+			if (num == global_qualify_peers) {
+				ms += global_qualify_gap;
+				num = 0;
+			} else {
+				num++;
+			}
+			AST_SCHED_REPLACE_UNREF(peer->pokeexpire, sched, ms, sip_poke_peer_s, peer,
+					unref_peer(_data, "removing poke peer ref"),
+					unref_peer(peer, "removing poke peer ref"),
+					ref_peer(peer, "adding poke peer ref"));
 		}
-		AST_SCHED_REPLACE_UNREF(peer->pokeexpire, sched, ms, sip_poke_peer_s, peer,
-				unref_peer(_data, "removing poke peer ref"),
-				unref_peer(peer, "removing poke peer ref"),
-				ref_peer(peer, "adding poke peer ref"));
 		ao2_unlock(peer);
 		unref_peer(peer, "toss iterator peer ptr");
 	}