diff -Nur openswan-2.4.5rc5/linux/net/ipsec/ipsec_tunnel.c openswan-2.4.5rc5.patched/linux/net/ipsec/ipsec_tunnel.c
--- openswan-2.4.5rc5/linux/net/ipsec/ipsec_tunnel.c	2005-11-22 05:11:52.000000000 +0100
+++ openswan-2.4.5rc5.patched/linux/net/ipsec/ipsec_tunnel.c	2006-03-29 01:13:35.000000000 +0200
@@ -33,6 +33,7 @@
 #include <linux/types.h>  /* size_t */
 #include <linux/interrupt.h> /* mark_bh */
 
+#include <net/arp.h>
 #include <net/tcp.h>
 #include <net/udp.h>
 #include <linux/skbuff.h>
