LXR linux/net/ipv6/netfilter/ip6t

   1// SPDX-License-Identifier: GPL-2.0-only
   2/* Kernel module to match EUI64 address parameters. */
   3
   4/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
   5 */
   6
   7#include <linux/module.h>
   8#include <linux/skbuff.h>
   9#include <linux/ipv6.h>
  10#include <linux/if_ether.h>
  11
  12#include <linux/netfilter/x_tables.h>
  13#include <linux/netfilter_ipv6/ip6_tables.h>
  14
  15MODULE_DESCRIPTION("Xtables: IPv6 EUI64 address match");
  16MODULE_LICENSE("GPL");
  17MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
  18
  19static bool
  20eui64_mt6(const struct sk_buff *skb, struct xt_action_param *par)
  21{
  22        unsigned char eui64[8];
  23
  24        if (!(skb_mac_header(skb) >= skb->head &&
  25              skb_mac_header(skb) + ETH_HLEN <= skb->data) &&
  26            par->fragoff != 0) {
  27                par->hotdrop = true;
  28                return false;
  29        }
  30
  31        memset(eui64, 0, sizeof(eui64));
  32
  33        if (eth_hdr(skb)->h_proto == htons(ETH_P_IPV6)) {
  34                if (ipv6_hdr(skb)->version == 0x6) {
  35                        memcpy(eui64, eth_hdr(skb)->h_source, 3);
  36                        memcpy(eui64 + 5, eth_hdr(skb)->h_source + 3, 3);
  37                        eui64[3] = 0xff;
  38                        eui64[4] = 0xfe;
  39                        eui64[0] ^= 0x02;
  40
  41                        if (!memcmp(ipv6_hdr(skb)->saddr.s6_addr + 8, eui64,
  42                                    sizeof(eui64)))
  43                                return true;
  44                }
  45        }
  46
  47        return false;
  48}
  49
  50static struct xt_match eui64_mt6_reg __read_mostly = {
  51        .name           = "eui64",
  52        .family         = NFPROTO_IPV6,
  53        .match          = eui64_mt6,
  54        .matchsize      = sizeof(int),
  55        .hooks          = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) |
  56                          (1 << NF_INET_FORWARD),
  57        .me             = THIS_MODULE,
  58};
  59
  60static int __init eui64_mt6_init(void)
  61{
  62        return xt_register_match(&eui64_mt6_reg);
  63}
  64
  65static void __exit eui64_mt6_exit(void)
  66{
  67        xt_unregister_match(&eui64_mt6_reg);
  68}
  69
  70module_init(eui64_mt6_init);
  71module_exit(eui64_mt6_exit);
  72