staticd: fix nht memory leak

When a static route with a gateway nexthop is created, the nexthop is
sent to zebra for NHT, and added to a local hash. When the nexthop's VRF
is deleted from kernel, nexthop still stays in the hash. This is a
memory leak, because it is never deleted from there. Even if the VRF is
recreated in kernel, it is assigned with a new `vrf_id` so the old hash
entry is not reused, and a new one is created. To fix the issue, remove
all nexthops from the hash when the corresponding VRF is deleted, do not
add nexthops to the hash if their corresponding VRF doesn't exist in
kernel and don't add the same nexthop to the hash multiple times.

Signed-off-by: Igor Ryzhov <[email protected]>

staticd/static_routes.c

@@ -87,11 +87,6 @@ void zebra_stable_node_cleanup(struct route_table *table,
 /* Install static path into rib. */
 void static_install_path(struct static_path *pn)
 {
-	struct static_nexthop *nh;
-
-	frr_each(static_nexthop_list, &pn->nexthop_list, nh)
-		static_zebra_nht_register(nh, true);
-
 	if (static_nexthop_list_count(&pn->nexthop_list))
 		static_zebra_route_add(pn, true);
 }
@@ -492,7 +487,6 @@ static void static_fixup_vrf(struct vrf *vrf, struct route_table *stable,
 					continue;
 
 				nh->nh_vrf_id = vrf->vrf_id;
-				nh->nh_registered = false;
 				if (nh->ifname[0]) {
 					ifp = if_lookup_by_name(nh->ifname,
 								nh->nh_vrf_id);
@@ -502,7 +496,7 @@ static void static_fixup_vrf(struct vrf *vrf, struct route_table *stable,
 						continue;
 				}
 
-				static_install_path(pn);
+				static_install_nexthop(nh);
 			}
 		}
 	}
@@ -520,31 +514,15 @@ static void static_fixup_vrf(struct vrf *vrf, struct route_table *stable,
 static void static_enable_vrf(struct route_table *stable, afi_t afi, safi_t safi)
 {
 	struct route_node *rn;
-	struct static_nexthop *nh;
-	struct interface *ifp;
 	struct static_path *pn;
 	struct static_route_info *si;
 
 	for (rn = route_top(stable); rn; rn = route_next(rn)) {
 		si = static_route_info_from_rnode(rn);
 		if (!si)
 			continue;
-		frr_each(static_path_list, &si->path_list, pn) {
-			frr_each(static_nexthop_list, &pn->nexthop_list, nh) {
-				if (nh->nh_vrf_id == VRF_UNKNOWN)
-					continue;
-				if (nh->ifname[0]) {
-					ifp = if_lookup_by_name(nh->ifname,
-								nh->nh_vrf_id);
-					if (ifp)
-						nh->ifindex = ifp->ifindex;
-					else
-						continue;
-				}
-
-				static_install_path(pn);
-			}
-		}
+		frr_each(static_path_list, &si->path_list, pn)
+			static_install_path(pn);
 	}
 }
 
@@ -606,7 +584,7 @@ static void static_cleanup_vrf(struct vrf *vrf, struct route_table *stable,
 				if (strcmp(vrf->name, nh->nh_vrfname) != 0)
 					continue;
 
-				static_uninstall_path(pn);
+				static_uninstall_nexthop(nh);
 
 				nh->nh_vrf_id = VRF_UNKNOWN;
 				nh->ifindex = IFINDEX_INTERNAL;
@@ -627,22 +605,15 @@ static void static_disable_vrf(struct route_table *stable,
 			       afi_t afi, safi_t safi)
 {
 	struct route_node *rn;
-	struct static_nexthop *nh;
 	struct static_path *pn;
 	struct static_route_info *si;
 
 	for (rn = route_top(stable); rn; rn = route_next(rn)) {
 		si = static_route_info_from_rnode(rn);
 		if (!si)
 			continue;
-		frr_each(static_path_list, &si->path_list, pn) {
-			frr_each(static_nexthop_list, &pn->nexthop_list, nh) {
-				if (nh->nh_vrf_id == VRF_UNKNOWN)
-					continue;
-
-				static_uninstall_path(pn);
-			}
-		}
+		frr_each(static_path_list, &si->path_list, pn)
+			static_uninstall_path(pn);
 	}
 }