diff --git a/zebra/rt_netlink.c b/zebra/rt_netlink.c
index 15475e2..ab28ad2 100644
--- a/zebra/rt_netlink.c
+++ b/zebra/rt_netlink.c
@@ -1985,7 +1985,7 @@
   };
 
   struct sock_fprog prog = {
-    .len = sizeof(filter) / sizeof(filter[0]),
+    .len = array_size(filter),
     .filter = filter,
   };