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
  28 mac_mt(const struct sk_buff *skb, const struct net_device *in,
  29        const struct net_device *out, const struct xt_match *match,
  30        const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop)
  31 {
  32     const struct xt_mac_info *info = matchinfo;
  33
  34     /* Is mac pointer valid? */
  35     return skb_mac_header(skb) >= skb->head &&
  36            skb_mac_header(skb) + ETH_HLEN <= skb->data
  37            /* If so, compare... */
  38            && ((!compare_ether_addr(eth_hdr(skb)->h_source, info->srcaddr))
  39                 ^ info->invert);
  40 }
  41
  42 static struct xt_match mac_mt_reg[] __read_mostly = {
  43         {
  44                 .name           = "mac",
  45                 .family         = AF_INET,
  46                 .match          = mac_mt,
  47                 .matchsize      = sizeof(struct xt_mac_info),
  48                 .hooks          = (1 << NF_INET_PRE_ROUTING) |
  49                                   (1 << NF_INET_LOCAL_IN) |
  50                                   (1 << NF_INET_FORWARD),
  51                 .me             = THIS_MODULE,
  52         },
  53         {
  54                 .name           = "mac",
  55                 .family         = AF_INET6,
  56                 .match          = mac_mt,
  57                 .matchsize      = sizeof(struct xt_mac_info),
  58                 .hooks          = (1 << NF_INET_PRE_ROUTING) |
  59                                   (1 << NF_INET_LOCAL_IN) |
  60                                   (1 << NF_INET_FORWARD),
  61                 .me             = THIS_MODULE,
  62         },
  63 };
  64
  65 static int __init mac_mt_init(void)
  66 {
  67         return xt_register_matches(mac_mt_reg, ARRAY_SIZE(mac_mt_reg));
  68 }
  69
  70 static void __exit mac_mt_exit(void)
  71 {
  72         xt_unregister_matches(mac_mt_reg, ARRAY_SIZE(mac_mt_reg));
  73 }
  74
  75 module_init(mac_mt_init);
  76 module_exit(mac_mt_exit);