From: root <root@dev.vmware.com>
Date: Mon, 19 Nov 2018 12:35:32 +0000 (-0800)
Subject: bgpd: Creating Loopback Interface Flaps BGPd (#2865)
X-Git-Tag: frr-7.0.1~184^2
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=36dc75886db92145540585ab203c0c9d339a9dae;p=mirror_frr.git

bgpd: Creating Loopback Interface Flaps BGPd (#2865)

* The function bgp_router_id_zebra_bump() will check for active bgp
  peers before chenging the router ID.
  If there are established peers, router ID is not modified
  which prevents the flapping of established peer connection

* Added field in bgp structure to store the count of established peers

Signed-off-by: kssoman <somanks@vmware.com>
---

diff --git a/bgpd/bgp_fsm.c b/bgpd/bgp_fsm.c
index 1f0cfd6e2..b70c8bbd6 100644
--- a/bgpd/bgp_fsm.c
+++ b/bgpd/bgp_fsm.c
@@ -935,9 +935,29 @@ static void bgp_update_delay_process_status_change(struct peer *peer)
    read/write and timer thread. */
 void bgp_fsm_change_status(struct peer *peer, int status)
 {
+	struct bgp *bgp;
+	uint32_t peer_count;
 
 	bgp_dump_state(peer, peer->status, status);
 
+	bgp = peer->bgp;
+	peer_count = bgp->established_peers;
+
+	if (status == Established)
+		bgp->established_peers++;
+	else if ((peer->status == Established) && (status != Established))
+		bgp->established_peers--;
+
+	if (BGP_DEBUG(neighbor_events, NEIGHBOR_EVENTS))
+		zlog_debug("%s : vrf %u, established_peers %u", __func__,
+				bgp->vrf_id, bgp->established_peers);
+	/* Set to router ID to the value provided by RIB if there are no peers
+	 * in the established state and peer count did not change
+	 */
+	if ((peer_count != bgp->established_peers) &&
+	    (bgp->established_peers == 0))
+		bgp_router_id_zebra_bump(bgp->vrf_id, NULL);
+
 	/* Transition into Clearing or Deleted must /always/ clear all routes..
 	 * (and must do so before actually changing into Deleted..
 	 */
diff --git a/bgpd/bgpd.c b/bgpd/bgpd.c
index a078c4f58..48a3b1bb0 100644
--- a/bgpd/bgpd.c
+++ b/bgpd/bgpd.c
@@ -274,6 +274,10 @@ void bgp_router_id_zebra_bump(vrf_id_t vrf_id, const struct prefix *router_id)
 {
 	struct listnode *node, *nnode;
 	struct bgp *bgp;
+	struct in_addr *addr = NULL;
+
+	if (router_id != NULL)
+		addr = (struct in_addr *)&(router_id->u.prefix4);
 
 	if (vrf_id == VRF_DEFAULT) {
 		/* Router-id change for default VRF has to also update all
@@ -282,17 +286,43 @@ void bgp_router_id_zebra_bump(vrf_id_t vrf_id, const struct prefix *router_id)
 			if (bgp->inst_type == BGP_INSTANCE_TYPE_VRF)
 				continue;
 
-			bgp->router_id_zebra = router_id->u.prefix4;
-			if (!bgp->router_id_static.s_addr)
-				bgp_router_id_set(bgp, &router_id->u.prefix4);
+			if (addr)
+				bgp->router_id_zebra = *addr;
+			else
+				addr = &bgp->router_id_zebra;
+
+			if (!bgp->router_id_static.s_addr) {
+				/* Router ID is updated if there are no active
+				 * peer sessions
+				 */
+				if (bgp->established_peers == 0) {
+					if (BGP_DEBUG(zebra, ZEBRA))
+						zlog_debug("RID change : vrf %u, RTR ID %s",
+					bgp->vrf_id, inet_ntoa(*addr));
+					bgp_router_id_set(bgp, addr);
+				}
+			}
 		}
 	} else {
 		bgp = bgp_lookup_by_vrf_id(vrf_id);
 		if (bgp) {
-			bgp->router_id_zebra = router_id->u.prefix4;
+			if (addr)
+				bgp->router_id_zebra = *addr;
+			else
+				addr = &bgp->router_id_zebra;
+
+			if (!bgp->router_id_static.s_addr) {
+				/* Router ID is updated if there are no active
+				 * peer sessions
+				 */
+				if (bgp->established_peers == 0) {
+					if (BGP_DEBUG(zebra, ZEBRA))
+						zlog_debug("RID change : vrf %u, RTR ID %s",
+					bgp->vrf_id, inet_ntoa(*addr));
+					bgp_router_id_set(bgp, addr);
+				}
+			}
 
-			if (!bgp->router_id_static.s_addr)
-				bgp_router_id_set(bgp, &router_id->u.prefix4);
 		}
 	}
 }
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index 70193104b..383fbc1c9 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -542,6 +542,9 @@ struct bgp {
 	/* local esi hash table */
 	struct hash *esihash;
 
+	/* Count of peers in established state */
+	uint32_t established_peers;
+
 	QOBJ_FIELDS
 };
 DECLARE_QOBJ_TYPE(bgp)
@@ -1886,5 +1889,4 @@ extern void bgp_update_redist_vrf_bitmaps(struct bgp *, vrf_id_t);
 
 /* For benefit of rfapi */
 extern struct peer *peer_new(struct bgp *bgp);
-
 #endif /* _QUAGGA_BGPD_H */