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(:title ipt_cs577.c :)

/* ipt_cs577.c */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netfilter_ipv4/ip_tables.h>

static int match(const struct sk_buff *skb,
                 const struct net_device *in,
                 const struct net_device *out,
                 const void *matchinfo,
                 int offset,
                 int *hotdrop)
{
	struct iphdr *iph = skb->nh.iph;

	printk(KERN_INFO "ipt_cs577: IN=%s OUT=%s TOS=0x%02X "
	       "TTL=%x SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ID=%u\n",

	       in ? (char *)in : "", out ? (char *)out : "", iph->tos,
	       iph->ttl, NIPQUAD(iph->saddr), NIPQUAD(iph->daddr),
	       ntohs(iph->id));

	return 1;
}

static int cs577_checkentry(const char *tablename,
                             const struct ipt_ip *ip,
                             void *matchinfo,
                             unsigned int matchsize,
                             unsigned int hook_mask)
{
	if (hook_mask & ~((1 << NF_IP_LOCAL_IN) | (1 << NF_IP_LOCAL_OUT))) {
		printk( "ipt_cs577: only valid with the FILTER table.\n");
		return 0;
	}

	if (matchsize != 0) {
		printk(KERN_ERR "ipt_cs577: matchsize differs\n");
		return 0;
	}

	printk(KERN_INFO "ipt_cs577: Registered in the %s table, "
	       "hook=%x, proto=%u\n", tablename, hook_mask, ip->proto);

	return 1;
}

static struct ipt_match cs577_match = {
	.list = {NULL, NULL},
	.name = "cs577",
	.revision = 0,
	.match = match,
	.checkentry = cs577_checkentry,
	.destroy = NULL,
	.me = THIS_MODULE
};

static int __init init(void)
{
	int val;
	val = ipt_register_match(&cs577_match);
	printk(KERN_INFO "ipt_cs577: init = %d\n", val);
	return val;
}

static void __exit fini(void)
{
	printk(KERN_INFO "ipt_cs577: exit!\n");
	ipt_unregister_match(&cs577_match);
}

module_init(init);
module_exit(fini);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Nicolas Bouliane && Samuel Jean");
MODULE_DESCRIPTION("netfilter module skeleton");