[nh] rtnl_nh_set_group Handle case where size is 0 but entries is set

That is invalid input. When size is 0 it means we want to reset the
group thus having an entries argument does not make sense.

Signed-off-by: Christoph Paasch <[email protected]>

Author: cpaasch-oai

lib/route/nh.c

@@ -430,6 +430,8 @@ int rtnl_nh_set_group(struct rtnl_nh *nexthop,
 
 	if (size == 0) {
 		/* size is 0, thus we want to remove the nh group */
+		if (entries)
+			return -NLE_INVAL;
 
 		rtnl_nh_grp_put(nexthop->nh_group);
 		nexthop->nh_group = NULL;