1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Kernel module to match MAC address parameters. */
3 
4 /* (C) 1999-2001 Paul `Rusty' Russell
5  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
6  */
7 
8 #include <linux/module.h>
9 #include <linux/skbuff.h>
10 #include <linux/if_arp.h>
11 #include <linux/if_ether.h>
12 #include <linux/etherdevice.h>
13 
14 #include <linux/netfilter_ipv4.h>
15 #include <linux/netfilter_ipv6.h>
16 #include <linux/netfilter/xt_mac.h>
17 #include <linux/netfilter/x_tables.h>
18 
19 MODULE_LICENSE("GPL");
20 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
21 MODULE_DESCRIPTION("Xtables: MAC address match");
22 MODULE_ALIAS("ipt_mac");
23 MODULE_ALIAS("ip6t_mac");
24 
mac_mt(const struct sk_buff * skb,struct xt_action_param * par)25 static bool mac_mt(const struct sk_buff *skb, struct xt_action_param *par)
26 {
27 	const struct xt_mac_info *info = par->matchinfo;
28 	bool ret;
29 
30 	if (skb->dev == NULL || skb->dev->type != ARPHRD_ETHER)
31 		return false;
32 	if (skb_mac_header(skb) < skb->head)
33 		return false;
34 	if (skb_mac_header(skb) + ETH_HLEN > skb->data)
35 		return false;
36 	ret  = ether_addr_equal(eth_hdr(skb)->h_source, info->srcaddr);
37 	ret ^= info->invert;
38 	return ret;
39 }
40 
41 static struct xt_match mac_mt_reg __read_mostly = {
42 	.name      = "mac",
43 	.revision  = 0,
44 	.family    = NFPROTO_UNSPEC,
45 	.match     = mac_mt,
46 	.matchsize = sizeof(struct xt_mac_info),
47 	.hooks     = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) |
48 	             (1 << NF_INET_FORWARD),
49 	.me        = THIS_MODULE,
50 };
51 
mac_mt_init(void)52 static int __init mac_mt_init(void)
53 {
54 	return xt_register_match(&mac_mt_reg);
55 }
56 
mac_mt_exit(void)57 static void __exit mac_mt_exit(void)
58 {
59 	xt_unregister_match(&mac_mt_reg);
60 }
61 
62 module_init(mac_mt_init);
63 module_exit(mac_mt_exit);
64