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/xt_mac.h>
  18 #include <linux/netfilter/x_tables.h>
  19
  20 MODULE_LICENSE("GPL");
  21 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
  22 MODULE_DESCRIPTION("iptables mac matching module");
  23 MODULE_ALIAS("ipt_mac");
  24 MODULE_ALIAS("ip6t_mac");
  25
  26 static int
  27 match(const struct sk_buff *skb,
  28       const struct net_device *in,
  29       const struct net_device *out,
  30       const struct xt_match *match,
  31       const void *matchinfo,
  32       int offset,
  33       unsigned int protoff,
  34       int *hotdrop)
  35 {
  36     const struct xt_mac_info *info = matchinfo;
  37
  38     /* Is mac pointer valid? */
  39     return (skb->mac.raw >= skb->head
  40             && (skb->mac.raw + ETH_HLEN) <= skb->data
  41             /* If so, compare... */
  42             && ((!compare_ether_addr(eth_hdr(skb)->h_source, info->srcaddr))
  43                 ^ info->invert));
  44 }
  45
  46 static struct xt_match mac_match = {
  47         .name           = "mac",
  48         .match          = match,
  49         .matchsize      = sizeof(struct xt_mac_info),
  50         .hooks          = (1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_LOCAL_IN) |
  51                           (1 << NF_IP_FORWARD),
  52         .family         = AF_INET,
  53         .me             = THIS_MODULE,
  54 };
  55 static struct xt_match mac6_match = {
  56         .name           = "mac",
  57         .match          = match,
  58         .matchsize      = sizeof(struct xt_mac_info),
  59         .hooks          = (1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_LOCAL_IN) |
  60                           (1 << NF_IP_FORWARD),
  61         .family         = AF_INET6,
  62         .me             = THIS_MODULE,
  63 };
  64
  65 static int __init xt_mac_init(void)
  66 {
  67         int ret;
  68         ret = xt_register_match(&mac_match);
  69         if (ret)
  70                 return ret;
  71
  72         ret = xt_register_match(&mac6_match);
  73         if (ret)
  74                 xt_unregister_match(&mac_match);
  75
  76         return ret;
  77 }
  78
  79 static void __exit xt_mac_fini(void)
  80 {
  81         xt_unregister_match(&mac_match);
  82         xt_unregister_match(&mac6_match);
  83 }
  84
  85 module_init(xt_mac_init);
  86 module_exit(xt_mac_fini);