zebra: fix wrong nexthop status for kernel routes

The kernel routes are wronlgy active even the nexthop interface is linkdown. Use `ip link set dev <interface> down` on the other box to set the box's nexthop interface linkdown. The kernel routes will be kept as `linkdown`, but are still with active nexthop in `zebra`. Add three changes for kernel routes in this commit: 1) The active nexthop should be the operative interface. 2) Don't uninstall the kernel routes from `zebra` even no active nexthops. (It doesn't affect the kernel routes' deletion from kernel netlink messages.) 3) Update the kernel routes when the nexthop interface becomes up. Before: (during nexthop interface is linkdown) ``` K>* 3.3.3.3/32 [0/0] via 88.88.88.1, enp2s0, weight 1, 00:00:14 ``` After: (during nexthop interface is linkdown) ``` K 3.3.3.3/32 [0/0] via 88.88.88.1, enp2s0 inactive, weight 1, 00:00:07 ``` Signed-off-by: anlan_cs <[email protected]>
FRRouting · Dec 2, 2024 · b2834cd · b2834cd
1 parent ee5a345
commit b2834cd
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Showing 3 changed files with 4 additions and 2 deletions.
diff --git a/zebra/interface.c b/zebra/interface.c
@@ -972,6 +972,8 @@ void if_up(struct interface *ifp, bool install_connected)
 	event_ignore_late_timer(zif->speed_update);
 
 	if_addr_wakeup(ifp);
+
+	rib_update_handle_vrf_all(RIB_UPDATE_KERNEL, ZEBRA_ROUTE_KERNEL);
 }
 
 /* Interface goes down.  We have to manage different behavior of based

diff --git a/zebra/zebra_nhg.c b/zebra/zebra_nhg.c
@@ -2648,7 +2648,7 @@ static unsigned nexthop_active_check(struct route_node *rn,
 
 		ifp = if_lookup_by_index(nexthop->ifindex, nexthop->vrf_id);
 
-		if (ifp && ifp->vrf->vrf_id == vrf_id && if_is_up(ifp)) {
+		if (ifp && ifp->vrf->vrf_id == vrf_id && if_is_up(ifp) && if_is_operative(ifp)) {
 			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
 			goto skip_check;
 		}

diff --git a/zebra/zebra_rib.c b/zebra/zebra_rib.c
@@ -1480,7 +1480,7 @@ static void rib_process(struct route_node *rn)
 		rib_process_update_fib(zvrf, rn, old_fib, new_fib);
 	else if (new_fib)
 		rib_process_add_fib(zvrf, rn, new_fib);
-	else if (old_fib)
+	else if (old_fib && !RIB_SYSTEM_ROUTE(old_fib))
 		rib_process_del_fib(zvrf, rn, old_fib);
 
 	/* Remove all RE entries queued for removal */