diff --git a/isisd/isis_tlv.c b/isisd/isis_tlv.c
index 7b99ab5..94fa65e 100644
--- a/isisd/isis_tlv.c
+++ b/isisd/isis_tlv.c
@@ -45,6 +45,11 @@
 
 extern struct isis *isis;
 
+/*
+ * Prototypes.
+ */
+int add_tlv (u_char, u_char, u_char *, struct stream *);
+
 void
 free_tlv (void *val)
 {