ip,ip6: allow deleting routes with directly connected nexthops

Previously, attempting to delete a route whose nexthop is directly
connected (i.e., not a gateway) would fail with -EBUSY. For example:
 add  ip address 6.6.7.7/24 iface p4
 add ip route 83.0.0.0/24 via 6.6.7.7
 del ip route 83.0.0.0/24
 error: command failed: Device or resource busy

This behavior stems from route4/6_del, which checks whether the nexthop is
a gateway before allowing deletion. If not, it assumes the nexthop is still
in use and blocks the operation.

However, there is no functional reason to prevent deletion in this
case. The underlying rib4/6_del logic ensures that a nexthop is only fully
removed when its reference count drops to zero—preserving it as long as
it's still needed by a connected route.

Signed-off-by: Maxime Leroy <[email protected]>

Author: maxime-leroy

modules/ip/control/route.c

@@ -250,9 +250,6 @@ static struct api_out route4_del(const void *request, void ** /*response*/) {
 		return api_out(ENOENT, 0);
 	}
 
-	if (!(nh->flags & GR_NH_F_GATEWAY))
-		return api_out(EBUSY, 0);
-
 	if (rib4_delete(req->vrf_id, req->dest.ip, req->dest.prefixlen) < 0)
 		return api_out(errno, 0);
 

modules/ip6/control/route.c

@@ -276,9 +276,6 @@ static struct api_out route6_del(const void *request, void ** /*response*/) {
 		return api_out(ENOENT, 0);
 	}
 
-	if (!(nh->flags & GR_NH_F_GATEWAY))
-		return api_out(EBUSY, 0);
-
 	if (rib6_delete(req->vrf_id, nh->iface_id, &req->dest.ip, req->dest.prefixlen) < 0)
 		return api_out(errno, 0);