/* Kernel module to match MAC address parameters. */
  
  /* (C) 1999-2001 Paul `Rusty' Russell
   * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   *
   * 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/module.h>
  #include <linux/skbuff.h>

  #include <linux/if_arp.h>

  #include <linux/if_ether.h>

  #include <linux/etherdevice.h>

  #include <linux/netfilter_ipv4.h>

  #include <linux/netfilter_ipv6.h>

  #include <linux/netfilter/xt_mac.h>
  #include <linux/netfilter/x_tables.h>

  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");

  MODULE_DESCRIPTION("Xtables: MAC address match");

  MODULE_ALIAS("ipt_mac");
  MODULE_ALIAS("ip6t_mac");

  static bool mac_mt(const struct sk_buff *skb, struct xt_action_param *par)

  {

  	const struct xt_mac_info *info = par->matchinfo;
  	bool ret;

  	if (skb->dev == NULL || skb->dev->type != ARPHRD_ETHER)
  		return false;

  	if (skb_mac_header(skb) < skb->head)
  		return false;
  	if (skb_mac_header(skb) + ETH_HLEN > skb->data)
  		return false;

  	ret  = ether_addr_equal(eth_hdr(skb)->h_source, info->srcaddr);

  	ret ^= info->invert;
  	return ret;

  }

  static struct xt_match mac_mt_reg __read_mostly = {
  	.name      = "mac",
  	.revision  = 0,
  	.family    = NFPROTO_UNSPEC,
  	.match     = mac_mt,
  	.matchsize = sizeof(struct xt_mac_info),
  	.hooks     = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) |
  	             (1 << NF_INET_FORWARD),
  	.me        = THIS_MODULE,

  };

  static int __init mac_mt_init(void)

  {

  	return xt_register_match(&mac_mt_reg);

  }

  static void __exit mac_mt_exit(void)

  {

  	xt_unregister_match(&mac_mt_reg);

  }

  module_init(mac_mt_init);
  module_exit(mac_mt_exit);