[FRR]Fixing route update on duplicate link up event in promiscuous mode

Author: dgsudharsan

src/sonic-frr/patch/0082-Revert-bgpd-upon-if-event-evaluate-bnc-with-matching.patch

@@ -0,0 +1,78 @@
+From 086c32eb5bf2ebfb4805f76219c1a3bc5dd9213e Mon Sep 17 00:00:00 2001
+From: dgsudharsan <sudharsand@nvidia.com>
+Date: Wed, 19 Feb 2025 17:24:39 +0000
+Subject: [PATCH] Revert "bgpd: upon if event, evaluate bnc with matching
+ nexthop"
+
+This reverts commit 58592be57783a3b24e7351af2a5afc61299768df.
+
+diff --git a/bgpd/bgp_nht.c b/bgpd/bgp_nht.c
+index 196cc00385..78eb1a9183 100644
+--- a/bgpd/bgp_nht.c
++++ b/bgpd/bgp_nht.c
+@@ -751,10 +751,6 @@ static void bgp_nht_ifp_table_handle(struct bgp *bgp,
+ 				     struct interface *ifp, bool up)
+ {
+ 	struct bgp_nexthop_cache *bnc;
+-	struct nexthop *nhop;
+-	uint16_t other_nh_count;
+-	bool nhop_ll_found = false;
+-	bool nhop_found = false;
+ 
+ 	if (ifp->ifindex == IFINDEX_INTERNAL) {
+ 		zlog_warn("%s: The interface %s ignored", __func__, ifp->name);
+@@ -762,42 +758,9 @@ static void bgp_nht_ifp_table_handle(struct bgp *bgp,
+ 	}
+ 
+ 	frr_each (bgp_nexthop_cache, table, bnc) {
+-		other_nh_count = 0;
+-		nhop_ll_found = bnc->ifindex_ipv6_ll == ifp->ifindex;
+-		for (nhop = bnc->nexthop; nhop; nhop = nhop->next) {
+-			if (nhop->ifindex == bnc->ifindex_ipv6_ll)
+-				continue;
+-
+-			if (nhop->ifindex != ifp->ifindex) {
+-				other_nh_count++;
+-				continue;
+-			}
+-			if (nhop->vrf_id != ifp->vrf->vrf_id) {
+-				other_nh_count++;
+-				continue;
+-			}
+-			nhop_found = true;
+-		}
+-
+-		if (!nhop_found && !nhop_ll_found)
+-			/* The event interface does not match the nexthop cache
+-			 * entry */
+-			continue;
+-
+-		if (!up && other_nh_count > 0)
+-			/* Down event ignored in case of multiple next-hop
+-			 * interfaces. The other might interfaces might be still
+-			 * up. The cases where all interfaces are down or a bnc
+-			 * is invalid are processed by a separate zebra rnh
+-			 * messages.
+-			 */
++		if (bnc->ifindex_ipv6_ll != ifp->ifindex)
+ 			continue;
+ 
+-		if (!nhop_ll_found) {
+-			evaluate_paths(bnc);
+-			continue;
+-		}
+-
+ 		bnc->last_update = monotime(NULL);
+ 		bnc->change_flags = 0;
+ 
+@@ -810,7 +773,6 @@ static void bgp_nht_ifp_table_handle(struct bgp *bgp,
+ 		if (up) {
+ 			SET_FLAG(bnc->flags, BGP_NEXTHOP_VALID);
+ 			SET_FLAG(bnc->change_flags, BGP_NEXTHOP_CHANGED);
+-			/* change nexthop number only for ll */
+ 			bnc->nexthop_num = 1;
+ 		} else {
+ 			UNSET_FLAG(bnc->flags, BGP_NEXTHOP_PEER_NOTIFIED);
+-- 
+2.43.2
+

src/sonic-frr/patch/series

@@ -60,3 +60,4 @@
 0078-vtysh-de-conditionalize-and-reorder-install-node.patch
 0079-staticd-add-support-for-srv6.patch
 0081-bgpd-Optimize-evaluate-paths-for-a-peer-going-down.patch
+0082-Revert-bgpd-upon-if-event-evaluate-bnc-with-matching.patch