Implement a timeout for the session initialization FSM.

This prevents neighbors stuck in the initialization FSM to linger forever
as long as the associated transport connection is up.

This timeout can be seen in the 'Session Initialization State Transition
Diagram' of RFC 5036. The RFC, however, doesn't specify how much we
should wait. Let's use 180 seconds for that, the default LDP hold time.

Fixes IxANVL LDP test 6.15.

3 files changed, 46 insertions, 3 deletions

diff --git a/usr.sbin/ldpd/ldpe.h b/usr.sbin/ldpd/ldpe.h
index 52a10a60d22..62341870b52 100644
--- a/usr.sbin/ldpd/ldpe.h
+++ b/usr.sbin/ldpd/ldpe.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ldpe.h,v 1.59 2016/06/11 01:46:36 renato Exp $ */
+/*	$OpenBSD: ldpe.h,v 1.60 2016/06/13 20:19:40 renato Exp $ */
 
 /*
  * Copyright (c) 2013, 2016 Renato Westphal <renato@openbsd.org>
@@ -68,6 +68,7 @@ struct nbr {
 	struct event		 ev_connect;
 	struct event		 keepalive_timer;
 	struct event		 keepalive_timeout;
+	struct event		 init_timeout;
 	struct event		 initdelay_timer;
 
 	struct mapping_head	 mapping_list;
@@ -228,6 +229,7 @@ int			 nbr_adj_count(struct nbr *, int);
 int			 nbr_session_active_role(struct nbr *);
 void			 nbr_stop_ktimer(struct nbr *);
 void			 nbr_stop_ktimeout(struct nbr *);
+void			 nbr_stop_itimeout(struct nbr *);
 void			 nbr_start_idtimer(struct nbr *);
 void			 nbr_stop_idtimer(struct nbr *);
 int			 nbr_pending_idtimer(struct nbr *);
diff --git a/usr.sbin/ldpd/neighbor.c b/usr.sbin/ldpd/neighbor.c
index 5755bd1fa11..4b607c0ce3f 100644
--- a/usr.sbin/ldpd/neighbor.c
+++ b/usr.sbin/ldpd/neighbor.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: neighbor.c,v 1.72 2016/05/23 19:20:55 renato Exp $ */
+/*	$OpenBSD: neighbor.c,v 1.73 2016/06/13 20:19:40 renato Exp $ */
 
 /*
  * Copyright (c) 2013, 2016 Renato Westphal <renato@openbsd.org>
@@ -41,6 +41,8 @@ static void		 nbr_ktimer(int, short, void *);
 static void		 nbr_start_ktimer(struct nbr *);
 static void		 nbr_ktimeout(int, short, void *);
 static void		 nbr_start_ktimeout(struct nbr *);
+static void		 nbr_itimeout(int, short, void *);
+static void		 nbr_start_itimeout(struct nbr *);
 static void		 nbr_idtimer(int, short, void *);
 static int		 nbr_act_session_operational(struct nbr *);
 static void		 nbr_send_labelmappings(struct nbr *);
@@ -164,6 +166,11 @@ nbr_fsm(struct nbr *nbr, enum nbr_event event)
 		}
 	}
 
+	if (nbr->state == NBR_STA_OPER || nbr->state == NBR_STA_PRESENT)
+		nbr_stop_itimeout(nbr);
+	else
+		nbr_start_itimeout(nbr);
+
 	switch (nbr_fsm_tbl[i].action) {
 	case NBR_ACT_RST_KTIMEOUT:
 		nbr_start_ktimeout(nbr);
@@ -259,6 +266,7 @@ nbr_new(struct in_addr id, int af, int ds_tlv, union ldpd_addr *addr,
 	/* set event structures */
 	evtimer_set(&nbr->keepalive_timeout, nbr_ktimeout, nbr);
 	evtimer_set(&nbr->keepalive_timer, nbr_ktimer, nbr);
+	evtimer_set(&nbr->init_timeout, nbr_itimeout, nbr);
 	evtimer_set(&nbr->initdelay_timer, nbr_idtimer, nbr);
 
 	nbrp = nbr_params_find(leconf, nbr->id);
@@ -286,6 +294,7 @@ nbr_del(struct nbr *nbr)
 		event_del(&nbr->ev_connect);
 	nbr_stop_ktimer(nbr);
 	nbr_stop_ktimeout(nbr);
+	nbr_stop_itimeout(nbr);
 	nbr_stop_idtimer(nbr);
 
 	mapping_list_clr(&nbr->mapping_list);
@@ -431,6 +440,37 @@ nbr_stop_ktimeout(struct nbr *nbr)
 		fatal(__func__);
 }
 
+/* Session initialization timeout: if nbr got stuck in the initialization FSM */
+
+static void
+nbr_itimeout(int fd, short event, void *arg)
+{
+	struct nbr *nbr = arg;
+
+	log_debug("%s: lsr-id %s", __func__, inet_ntoa(nbr->id));
+
+	nbr_fsm(nbr, NBR_EVT_CLOSE_SESSION);
+}
+
+static void
+nbr_start_itimeout(struct nbr *nbr)
+{
+	struct timeval	 tv;
+
+	timerclear(&tv);
+	tv.tv_sec = DEFAULT_KEEPALIVE;
+	if (evtimer_add(&nbr->init_timeout, &tv) == -1)
+		fatal(__func__);
+}
+
+void
+nbr_stop_itimeout(struct nbr *nbr)
+{
+	if (evtimer_pending(&nbr->init_timeout, NULL) &&
+	    evtimer_del(&nbr->init_timeout) == -1)
+		fatal(__func__);
+}
+
 /* Init delay timer: timer to retry to iniziatize session */
 
 static void
diff --git a/usr.sbin/ldpd/packet.c b/usr.sbin/ldpd/packet.c
index f8a7f45549b..a804a7f7c24 100644
--- a/usr.sbin/ldpd/packet.c
+++ b/usr.sbin/ldpd/packet.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: packet.c,v 1.62 2016/06/13 20:13:34 renato Exp $ */
+/*	$OpenBSD: packet.c,v 1.63 2016/06/13 20:19:40 renato Exp $ */
 
 /*
  * Copyright (c) 2013, 2016 Renato Westphal <renato@openbsd.org>
@@ -648,6 +648,7 @@ session_close(struct nbr *nbr)
 	tcp_close(nbr->tcp);
 	nbr_stop_ktimer(nbr);
 	nbr_stop_ktimeout(nbr);
+	nbr_stop_itimeout(nbr);
 }
 
 static ssize_t