/* Hop Limit matching module */

/* (C) 2001-2002 Maciej Soltysiak <solt@dns.toxicfilms.tv>
 * Based on HW's ttl module
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/ipv6.h>
#include <linux/module.h>
#include <linux/skbuff.h>

#include <linux/netfilter_ipv6/ip6t_hl.h>
#include <linux/netfilter/x_tables.h>

MODULE_AUTHOR("Maciej Soltysiak <solt@dns.toxicfilms.tv>");
MODULE_DESCRIPTION("Xtables: IPv6 Hop Limit field match");
MODULE_LICENSE("GPL");

static bool
hl_mt6(const struct sk_buff *skb, const struct net_device *in,
       const struct net_device *out, const struct xt_match *match,
       const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
{
	const struct ip6t_hl_info *info = matchinfo;
	const struct ipv6hdr *ip6h = ipv6_hdr(skb);

	switch (info->mode) {
		case IP6T_HL_EQ:
			return ip6h->hop_limit == info->hop_limit;
			break;
		case IP6T_HL_NE:
			return ip6h->hop_limit != info->hop_limit;
			break;
		case IP6T_HL_LT:
			return ip6h->hop_limit < info->hop_limit;
			break;
		case IP6T_HL_GT:
			return ip6h->hop_limit > info->hop_limit;
			break;
		default:
			printk(KERN_WARNING "ip6t_hl: unknown mode %d\n",
				info->mode);
			return false;
	}

	return false;
}

static struct xt_match hl_mt6_reg __read_mostly = {
	.name		= "hl",
	.family		= AF_INET6,
	.match		= hl_mt6,
	.matchsize	= sizeof(struct ip6t_hl_info),
	.me		= THIS_MODULE,
};

static int __init hl_mt6_init(void)
{
	return xt_register_match(&hl_mt6_reg);
}

static void __exit hl_mt6_exit(void)
{
	xt_unregister_match(&hl_mt6_reg);
}

module_init(hl_mt6_init);
module_exit(hl_mt6_exit);
