diff --git a/lib/linklist.h b/lib/linklist.h
index 6209c8b..96aaf43 100644
--- a/lib/linklist.h
+++ b/lib/linklist.h
@@ -68,6 +68,7 @@
 extern void listnode_add (struct list *, void *);
 extern void listnode_add_sort (struct list *, void *);
 extern void listnode_add_after (struct list *, struct listnode *, void *);
+extern struct listnode *listnode_add_before (struct list *, struct listnode *, void *);
 extern void listnode_move_to_tail (struct list *, struct listnode *);
 extern void listnode_delete (struct list *, void *);
 extern struct listnode *listnode_lookup (struct list *, void *);