#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4/ip_conntrack.h>

static int conntrack_event(struct notifier_block *this,
			   unsigned long events, 
			   void *ptr)
{
	struct ip_conntrack *ct = (struct ip_conntrack *)ptr;

	if (events & IPCT_DESTROY)
		printk("protonum=%d\n", ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum);

	return 0;
}

static struct notifier_block ctnl_notifier = { 
	.notifier_call = conntrack_event,
}; 

static int __init hello_init(void)
{
	int ret;

	need_conntrack();
	ret = ip_conntrack_register_notifier(&ctnl_notifier);
	if (ret < 0)
		printk("ipaddr_init: cannot register notifier.\n");

	return ret;
}

module_init(hello_init);

MODULE_LICENSE("GPL");