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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 
mac_mt(const struct sk_buff * skb,const struct xt_match_param * par)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 
mac_mt_init(void)50 static int __init mac_mt_init(void)
51 {
52 	return xt_register_match(&mac_mt_reg);
53 }
54 
mac_mt_exit(void)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);
62