LXR linux/net/ipv6/netfilter/ip6t

   1/* Kernel module to match EUI64 address parameters. */
   2
   3/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/skbuff.h>
  12#include <linux/ipv6.h>
  13#include <linux/if_ether.h>
  14
  15#include <linux/netfilter/x_tables.h>
  16#include <linux/netfilter_ipv6/ip6_tables.h>
  17
  18MODULE_DESCRIPTION("Xtables: IPv6 EUI64 address match");
  19MODULE_LICENSE("GPL");
  20MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
  21
  22static bool
  23eui64_mt6(const struct sk_buff *skb, struct xt_action_param *par)
  24{
  25        unsigned char eui64[8];
  26
  27        if (!(skb_mac_header(skb) >= skb->head &&
  28              skb_mac_header(skb) + ETH_HLEN <= skb->data) &&
  29            par->fragoff != 0) {
  30                par->hotdrop = true;
  31                return false;
  32        }
  33
  34        memset(eui64, 0, sizeof(eui64));
  35
  36        if (eth_hdr(skb)->h_proto == htons(ETH_P_IPV6)) {
  37                if (ipv6_hdr(skb)->version == 0x6) {
  38                        memcpy(eui64, eth_hdr(skb)->h_source, 3);
  39                        memcpy(eui64 + 5, eth_hdr(skb)->h_source + 3, 3);
  40                        eui64[3] = 0xff;
  41                        eui64[4] = 0xfe;
  42                        eui64[0] ^= 0x02;
  43
  44                        if (!memcmp(ipv6_hdr(skb)->saddr.s6_addr + 8, eui64,
  45                                    sizeof(eui64)))
  46                                return true;
  47                }
  48        }
  49
  50        return false;
  51}
  52
  53static struct xt_match eui64_mt6_reg __read_mostly = {
  54        .name           = "eui64",
  55        .family         = NFPROTO_IPV6,
  56        .match          = eui64_mt6,
  57        .matchsize      = sizeof(int),
  58        .hooks          = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) |
  59                          (1 << NF_INET_FORWARD),
  60        .me             = THIS_MODULE,
  61};
  62
  63static int __init eui64_mt6_init(void)
  64{
  65        return xt_register_match(&eui64_mt6_reg);
  66}
  67
  68static void __exit eui64_mt6_exit(void)
  69{
  70        xt_unregister_match(&eui64_mt6_reg);
  71}
  72
  73module_init(eui64_mt6_init);
  74module_exit(eui64_mt6_exit);
  75