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/*

 * Hop Limit matching module

 * Maciej Soltysiak <solt@dns.toxicfilms.tv>

 * Based on HW's ttl module

 *

 * This software is distributed under the terms  GNU GPL

 */

#include <linux/module.h>

#include <linux/skbuff.h>

#include <linux/netfilter_ipv6/ip6t_hl.h>

#include <linux/netfilter_ipv6/ip6_tables.h>

MODULE_AUTHOR("Maciej Soltysiak <solt@dns.toxicfilms.tv>");

MODULE_DESCRIPTION("IP tables Hop Limit matching module");

MODULE_LICENSE("GPL");

static int match(const struct sk_buff *skb, const struct net_device *in,

                 const struct net_device *out, const void *matchinfo,

                 int offset, const void *hdr, u_int16_t datalen,

                 int *hotdrop)

{

        const struct ip6t_hl_info *info = matchinfo;

        const struct ipv6hdr *ip6h = skb->nh.ipv6h;

        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 0;

        }

        return 0;

}

static int checkentry(const char *tablename, const struct ip6t_ip6 *ip,

                      void *matchinfo, unsigned int matchsize,

                      unsigned int hook_mask)

{

        if (matchsize != IP6T_ALIGN(sizeof(struct ip6t_hl_info)))

                return 0;

        return 1;

}

static struct ip6t_match hl_match = { { NULL, NULL }, "hl", &match,

                &checkentry, NULL, THIS_MODULE };

static int __init init(void)

{

        return ip6t_register_match(&hl_match);

}

static void __exit fini(void)

{

        ip6t_unregister_match(&hl_match);

}

module_init(init);

module_exit(fini);