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_ether.h>
  14 #include <linux/etherdevice.h>
  15
  16 #include <linux/netfilter_ipv4.h>
  17 #include <linux/netfilter_ipv6.h>
  18 #include <linux/netfilter/xt_mac.h>
  19 #include <linux/netfilter/x_tables.h>
  20
  21 MODULE_LICENSE("GPL");
  22 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
  23 MODULE_DESCRIPTION("Xtables: MAC address match");
  24 MODULE_ALIAS("ipt_mac");
  25 MODULE_ALIAS("ip6t_mac");
  26
  27 static bool mac_mt(const struct sk_buff *skb, const struct xt_match_param *par)
  28 {
  29     const struct xt_mac_info *info = par->matchinfo;
  30
  31     /* Is mac pointer valid? */
  32     return skb_mac_header(skb) >= skb->head &&
  33            skb_mac_header(skb) + ETH_HLEN <= skb->data
  34            /* If so, compare... */
  35            && ((!compare_ether_addr(eth_hdr(skb)->h_source, info->srcaddr))
  36                 ^ info->invert);
  37 }
  38
  39 static struct xt_match mac_mt_reg __read_mostly = {
  40         .name      = "mac",
  41         .revision  = 0,
  42         .family    = NFPROTO_UNSPEC,
  43         .match     = mac_mt,
  44         .matchsize = sizeof(struct xt_mac_info),
  45         .hooks     = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) |
  46                      (1 << NF_INET_FORWARD),
  47         .me        = THIS_MODULE,
  48 };
  49
  50 static int __init mac_mt_init(void)
  51 {
  52         return xt_register_match(&mac_mt_reg);
  53 }
  54
  55 static void __exit mac_mt_exit(void)
  56 {
  57         xt_unregister_match(&mac_mt_reg);
  58 }
  59
  60 module_init(mac_mt_init);
  61 module_exit(mac_mt_exit);