bgpd: Allow registration of nexthops after zebra connection

If we attempt to register nexthops before we have the zebra
connection, they will not be installed.  After we have noticed
that we are up, re-install them.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

4 files changed, 46 insertions, 3 deletions

diff --git a/bgpd/bgp_nexthop.c b/bgpd/bgp_nexthop.c
index 5ed6fd6eb..2ef792e12 100644
--- a/bgpd/bgp_nexthop.c
+++ b/bgpd/bgp_nexthop.c
@@ -628,7 +628,10 @@ static void bgp_show_nexthops(struct vty *vty, struct bgp *bgp, int detail)
 				if (CHECK_FLAG(bnc->flags,
 					       BGP_NEXTHOP_CONNECTED))
 					vty_out(vty, "  Must be Connected\n");
-				}
+				if (!CHECK_FLAG(bnc->flags,
+						BGP_NEXTHOP_REGISTERED))
+					vty_out(vty, "  Is not Registered\n");
+			}
 			tbuf = time(NULL) - (bgp_clock() - bnc->last_update);
 			vty_out(vty, "  Last update: %s", ctime(&tbuf));
 			vty_out(vty, "\n");
diff --git a/bgpd/bgp_nht.c b/bgpd/bgp_nht.c
index 2e7f17fda..8aa7798af 100644
--- a/bgpd/bgp_nht.c
+++ b/bgpd/bgp_nht.c
@@ -240,8 +240,8 @@ int bgp_find_or_add_nexthop(struct bgp *bgp_route, struct bgp *bgp_nexthop,
 		UNSET_FLAG(bnc->flags, BGP_NEXTHOP_VALID);
 	}
 	if (bgp_route->inst_type == BGP_INSTANCE_TYPE_VIEW) {
-		bnc->flags |= BGP_NEXTHOP_REGISTERED;
-		bnc->flags |= BGP_NEXTHOP_VALID;
+		SET_FLAG(bnc->flags, BGP_NEXTHOP_REGISTERED);
+		SET_FLAG(bnc->flags, BGP_NEXTHOP_VALID);
 	} else if (!CHECK_FLAG(bnc->flags, BGP_NEXTHOP_REGISTERED))
 		register_zebra_rnh(bnc, is_bgp_static_route);
 	if (pi && pi->nexthop != bnc) {
@@ -594,6 +594,11 @@ static void sendmsg_zebra_rnh(struct bgp_nexthop_cache *bnc, int command)
 		return;
 	}
 
+	if (!bgp_zebra_num_connects()) {
+		if (BGP_DEBUG(zebra, ZEBRA))
+			zlog_debug("%s: We have not connected yet, cannot send nexthops",
+				   __PRETTY_FUNCTION__);
+	}
 	p = &(bnc->node->p);
 	if ((command == ZEBRA_NEXTHOP_REGISTER
 	     || command == ZEBRA_IMPORT_ROUTE_REGISTER)
@@ -806,3 +811,30 @@ void path_nh_map(struct bgp_path_info *path, struct bgp_nexthop_cache *bnc,
 		path->nexthop->path_count++;
 	}
 }
+
+/*
+ * This function is called to register nexthops to zebra
+ * as that we may have tried to install the nexthops
+ * before we actually have a zebra connection
+ */
+void bgp_nht_register_nexthops(struct bgp *bgp)
+{
+	struct bgp_node *rn;
+	struct bgp_nexthop_cache *bnc;
+	afi_t afi;
+
+	for (afi = AFI_IP; afi < AFI_MAX; afi++) {
+		if (!bgp->nexthop_cache_table[afi])
+			continue;
+
+		for (rn = bgp_table_top(bgp->nexthop_cache_table[afi]); rn;
+		     rn = bgp_route_next(rn)) {
+			bnc = bgp_nexthop_get_node_info(rn);
+
+			if (!bnc)
+				continue;
+
+			register_zebra_rnh(bnc, 0);
+		}
+	}
+}
diff --git a/bgpd/bgp_nht.h b/bgpd/bgp_nht.h
index 0cc045a06..96dd91559 100644
--- a/bgpd/bgp_nht.h
+++ b/bgpd/bgp_nht.h
@@ -81,5 +81,11 @@ extern void bgp_cleanup_nexthops(struct bgp *bgp);
  */
 extern void path_nh_map(struct bgp_path_info *path,
 			struct bgp_nexthop_cache *bnc, bool make);
+/*
+ * When we actually have the connection to
+ * the zebra daemon, we need to reregister
+ * any nexthops we may have sitting around
+ */
+extern void bgp_nht_register_nexthops(struct bgp *bgp);
 
 #endif /* _BGP_NHT_H */
diff --git a/bgpd/bgp_zebra.c b/bgpd/bgp_zebra.c
index 0b79a9ee1..50b790eb1 100644
--- a/bgpd/bgp_zebra.c
+++ b/bgpd/bgp_zebra.c
@@ -1837,6 +1837,8 @@ void bgp_zebra_instance_register(struct bgp *bgp)
 	 */
 	if (bgp->inst_type == BGP_INSTANCE_TYPE_DEFAULT && is_evpn_enabled())
 		bgp_zebra_advertise_all_vni(bgp, 1);
+
+	bgp_nht_register_nexthops(bgp);
 }
 
 /* Deregister this instance with Zebra. Invoked upon the instance