LXR linux/net/netfilter/xt

   1// SPDX-License-Identifier: GPL-2.0-only
   2/* Kernel module to match MAC address parameters. */
   3
   4/* (C) 1999-2001 Paul `Rusty' Russell
   5 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   6 */
   7
   8#include <linux/module.h>
   9#include <linux/skbuff.h>
  10#include <linux/if_arp.h>
  11#include <linux/if_ether.h>
  12#include <linux/etherdevice.h>
  13
  14#include <linux/netfilter_ipv4.h>
  15#include <linux/netfilter_ipv6.h>
  16#include <linux/netfilter/xt_mac.h>
  17#include <linux/netfilter/x_tables.h>
  18
  19MODULE_LICENSE("GPL");
  20MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
  21MODULE_DESCRIPTION("Xtables: MAC address match");
  22MODULE_ALIAS("ipt_mac");
  23MODULE_ALIAS("ip6t_mac");
  24
  25static bool mac_mt(const struct sk_buff *skb, struct xt_action_param *par)
  26{
  27        const struct xt_mac_info *info = par->matchinfo;
  28        bool ret;
  29
  30        if (skb->dev == NULL || skb->dev->type != ARPHRD_ETHER)
  31                return false;
  32        if (skb_mac_header(skb) < skb->head)
  33                return false;
  34        if (skb_mac_header(skb) + ETH_HLEN > skb->data)
  35                return false;
  36        ret  = ether_addr_equal(eth_hdr(skb)->h_source, info->srcaddr);
  37        ret ^= info->invert;
  38        return ret;
  39}
  40
  41static struct xt_match mac_mt_reg __read_mostly = {
  42        .name      = "mac",
  43        .revision  = 0,
  44        .family    = NFPROTO_UNSPEC,
  45        .match     = mac_mt,
  46        .matchsize = sizeof(struct xt_mac_info),
  47        .hooks     = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) |
  48                     (1 << NF_INET_FORWARD),
  49        .me        = THIS_MODULE,
  50};
  51
  52static int __init mac_mt_init(void)
  53{
  54        return xt_register_match(&mac_mt_reg);
  55}
  56
  57static void __exit mac_mt_exit(void)
  58{
  59        xt_unregister_match(&mac_mt_reg);
  60}
  61
  62module_init(mac_mt_init);
  63module_exit(mac_mt_exit);
  64