diff --git a/zebra/rib.h b/zebra/rib.h
index b21e087..1e6393e 100644
--- a/zebra/rib.h
+++ b/zebra/rib.h
@@ -32,6 +32,9 @@
   struct rib *next;
   struct rib *prev;
 
+  /* ref count */
+  unsigned int lock;
+  
   /* Type fo this route. */
   int type;