diff --git a/lib/table.h b/lib/table.h
index 45ec606..41d1fa7 100644
--- a/lib/table.h
+++ b/lib/table.h
@@ -66,13 +66,13 @@
 extern struct route_node *route_node_lookup (struct route_table *,
                                              struct prefix *);
 extern struct route_node *route_lock_node (struct route_node *node);
-extern struct route_node *route_node_match (struct route_table *, 
-                                            struct prefix *);
-extern struct route_node *route_node_match_ipv4 (struct route_table *,
-					  struct in_addr *);
+extern struct route_node *route_node_match (const struct route_table *,
+                                            const struct prefix *);
+extern struct route_node *route_node_match_ipv4 (const struct route_table *,
+						 const struct in_addr *);
 #ifdef HAVE_IPV6
-extern struct route_node *route_node_match_ipv6 (struct route_table *,
-					  struct in6_addr *);
+extern struct route_node *route_node_match_ipv6 (const struct route_table *,
+						 const struct in6_addr *);
 #endif /* HAVE_IPV6 */
 
 #endif /* _ZEBRA_TABLE_H */