--- arp.h.orig
+++ arp.h
@@ -11,6 +11,6 @@
 #ifndef _ARP_H_
 #define _ARP_H_
 
-int	arp_cache_lookup(in_addr_t ip, struct ether_addr *ether);
+int	arp_cache_lookup(in_addr_t ip, struct ether_addr *ether, const char *lif);
 
 #endif /* _ARP_H_ */