diff --git a/lib/prefix.h b/lib/prefix.h
index 9ef70ff..45889e0 100644
--- a/lib/prefix.h
+++ b/lib/prefix.h
@@ -52,6 +52,7 @@
       struct in_addr adv_router;
     } lp;
     u_char val[8];
+    uintptr_t ptr;
   } u __attribute__ ((aligned (8)));
 };
 
@@ -89,6 +90,14 @@
   u_char val[8] __attribute__ ((aligned (8)));
 };
 
+/* Prefix for a generic pointer */
+struct prefix_ptr
+{
+  u_char family;
+  u_char prefixlen;
+  uintptr_t prefix __attribute__ ((aligned (8)));
+};
+
 /* helper to get type safety/avoid casts on calls
  * (w/o this, functions accepting all prefix types need casts on the caller
  * side, which strips type safety since the cast will accept any pointer