zebra: Fix resetting valid flags for NHG dependents

Upon if_down, we don't reset the valid flag for dependents
and unset the INSTALLED flag.

So when its time for the NHG to be deleted (routes dereferenced),
zebra deletes it since refcnt goes to 0, but stale NHG remains in kernel.

Ticket :#4200788

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

Signed-off-by: Rajasekar Raja <rajasekarr@nvidia.com>
(cherry picked from commit 54ec9f3)

# Conflicts:
#	zebra/zebra_nhg.c

zebra/zebra_nhg.c

@@ -1064,6 +1064,7 @@ static struct nhg_ctx *nhg_ctx_init(uint32_t id, struct nexthop *nh,
 static void zebra_nhg_set_valid(struct nhg_hash_entry *nhe)
 {
 	struct nhg_connected *rb_node_dep;
+	bool dependent_valid = valid;
 
 	SET_FLAG(nhe->flags, NEXTHOP_GROUP_VALID);
 
@@ -1084,8 +1085,39 @@ static void zebra_nhg_set_invalid(struct nhg_hash_entry *nhe)
 		UNSET_FLAG(nhe->flags, NEXTHOP_GROUP_INSTALLED);
 
 	/* Update validity of nexthops depending on it */
+<<<<<<< HEAD
 	frr_each(nhg_connected_tree, &nhe->nhg_dependents, rb_node_dep)
 		zebra_nhg_check_valid(rb_node_dep->nhe);
+=======
+	frr_each (nhg_connected_tree, &nhe->nhg_dependents, rb_node_dep) {
+		dependent_valid = valid;
+		if (!valid) {
+			/*
+			 * Grab the first nexthop from the depending nexthop group
+			 * then let's find the nexthop in that group that matches
+			 * my individual nexthop and mark it as no longer ACTIVE
+			 */
+			struct nexthop *nexthop = rb_node_dep->nhe->nhg.nexthop;
+
+			while (nexthop) {
+				if (nexthop_same(nexthop, nhe->nhg.nexthop)) {
+					/* Invalid Nexthop */
+					UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
+				} else {
+					/*
+					 * If other nexthops in the nexthop
+					 * group are valid then we can continue
+					 * to use this nexthop group as valid
+					 */
+					if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE))
+						dependent_valid = true;
+				}
+				nexthop = nexthop->next;
+			}
+		}
+		zebra_nhg_set_valid(rb_node_dep->nhe, dependent_valid);
+	}
+>>>>>>> 54ec9f388 (zebra: Fix resetting valid flags for NHG dependents)
 }
 
 void zebra_nhg_check_valid(struct nhg_hash_entry *nhe)