Introduce a SessionDownTimer that is started when a session goes down

and is stopped when the session comes up (ESTABLISHED state).
Right now it is used to remove cloned sessions. For that the SessionDownTimer
is also started when a clone is created.
OK tb@

3 files changed, 27 insertions, 12 deletions

diff --git a/usr.sbin/bgpd/bgpd.h b/usr.sbin/bgpd/bgpd.h
index 9f435523a5c..b6a90cce936 100644
--- a/usr.sbin/bgpd/bgpd.h
+++ b/usr.sbin/bgpd/bgpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bgpd.h,v 1.502 2024/12/09 10:51:46 claudio Exp $ */
+/*	$OpenBSD: bgpd.h,v 1.503 2024/12/10 14:34:51 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -1761,6 +1761,7 @@ static const char * const timernames[] = {
 	"IdleHoldResetTimer",
 	"CarpUndemoteTimer",
 	"RestartTimer",
+	"SessionDownTimer",
 	"RTR RefreshTimer",
 	"RTR RetryTimer",
 	"RTR ExpireTimer",
diff --git a/usr.sbin/bgpd/session.c b/usr.sbin/bgpd/session.c
index dfa45c500a1..597ac25fd0b 100644
--- a/usr.sbin/bgpd/session.c
+++ b/usr.sbin/bgpd/session.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: session.c,v 1.501 2024/12/09 10:51:46 claudio Exp $ */
+/*	$OpenBSD: session.c,v 1.502 2024/12/10 14:34:51 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004, 2005 Henning Brauer <henning@openbsd.org>
@@ -257,13 +257,6 @@ session_main(int debug, int verbose)
 		/* check for peers to be initialized or deleted */
 		if (!pending_reconf) {
 			RB_FOREACH_SAFE(p, peer_head, &conf->peers, next) {
-				/* cloned peer that idled out? */
-				if (p->template && (p->state == STATE_IDLE ||
-				    p->state == STATE_ACTIVE) &&
-				    getmonotime() - p->stats.last_updown >=
-				    INTERVAL_HOLD_CLONED)
-					p->reconf_action = RECONF_DELETE;
-
 				/* new peer that needs init? */
 				if (p->state == STATE_NONE)
 					init_peer(p);
@@ -409,6 +402,14 @@ session_main(int debug, int verbose)
 					    Timer_RestartTimeout);
 					session_graceful_stop(p);
 					break;
+				case Timer_SessionDown:
+					timer_stop(&p->timers,
+					    Timer_SessionDown);
+					/* finally delete this cloned peer */
+					if (p->template)
+						p->reconf_action =
+						    RECONF_DELETE;
+					break;
 				default:
 					fatalx("King Bula lost in time");
 				}
@@ -2266,7 +2267,11 @@ parse_open(struct peer *peer, struct ibuf *msg)
 		return (-1);
 	}
 
-	/* if remote-as is zero and it's a cloned neighbor, accept any */
+	/*
+	 * if remote-as is zero and it's a cloned neighbor, accept any
+	 * but only on the first connect, after that the remote-as needs
+	 * to remain the same.
+	 */
 	if (peer->template && !peer->conf.remote_as && as != AS_TRANS) {
 		peer->conf.remote_as = as;
 		peer->conf.ebgp = (peer->conf.remote_as != peer->conf.local_as);
@@ -3338,6 +3343,9 @@ getpeerbyip(struct bgpd_config *c, struct sockaddr *ip)
 		newpeer->rpending = 0;
 		newpeer->wbuf = NULL;
 		init_peer(newpeer);
+		/* start delete timer, it is stopped when session goes up. */
+		timer_set(&newpeer->timers, Timer_SessionDown,
+		    INTERVAL_SESSION_DOWN);
 		bgp_fsm(newpeer, EVNT_START, NULL);
 		if (RB_INSERT(peer_head, &c->peers, newpeer) != NULL)
 			fatalx("%s: peer tree is corrupt", __func__);
@@ -3426,6 +3434,9 @@ session_down(struct peer *peer)
 {
 	memset(&peer->capa.neg, 0, sizeof(peer->capa.neg));
 	peer->stats.last_updown = getmonotime();
+
+	timer_set(&peer->timers, Timer_SessionDown, INTERVAL_SESSION_DOWN);
+
 	/*
 	 * session_down is called in the exit code path so check
 	 * if the RDE is still around, if not there is no need to
@@ -3449,6 +3460,8 @@ session_up(struct peer *p)
 	p->stats.last_rcvd_suberr = 0;
 	memset(p->stats.last_reason, 0, sizeof(p->stats.last_reason));
 
+	timer_stop(&p->timers, Timer_SessionDown);
+
 	if (imsg_rde(IMSG_SESSION_ADD, p->conf.id,
 	    &p->conf, sizeof(p->conf)) == -1)
 		fatalx("imsg_compose error");
diff --git a/usr.sbin/bgpd/session.h b/usr.sbin/bgpd/session.h
index 9759645ec28..34482524ae6 100644
--- a/usr.sbin/bgpd/session.h
+++ b/usr.sbin/bgpd/session.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: session.h,v 1.180 2024/11/21 13:34:30 claudio Exp $ */
+/*	$OpenBSD: session.h,v 1.181 2024/12/10 14:34:51 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -25,8 +25,8 @@
 #define	INTERVAL_HOLD_INITIAL		240
 #define	INTERVAL_HOLD			90
 #define	INTERVAL_IDLE_HOLD_INITIAL	30
-#define	INTERVAL_HOLD_CLONED		3600
 #define	INTERVAL_HOLD_DEMOTED		60
+#define	INTERVAL_SESSION_DOWN		3600
 #define	MAX_IDLE_HOLD			3600
 #define	MSGSIZE_HEADER			19
 #define	MSGSIZE_HEADER_MARKER		16
@@ -176,6 +176,7 @@ enum Timer {
 	Timer_IdleHoldReset,
 	Timer_CarpUndemote,
 	Timer_RestartTimeout,
+	Timer_SessionDown,
 	Timer_Rtr_Refresh,
 	Timer_Rtr_Retry,
 	Timer_Rtr_Expire,