net/netfilter/xt_mac.c

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