1/* Kernel module to match EUI64 address parameters. */
2
3/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/ipv6.h>
13#include <linux/if_ether.h>
14
15#include <linux/netfilter/x_tables.h>
16#include <linux/netfilter_ipv6/ip6_tables.h>
17
18MODULE_DESCRIPTION("Xtables: IPv6 EUI64 address match");
19MODULE_LICENSE("GPL");
20MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
21
22static bool
23eui64_mt6(const struct sk_buff *skb, struct xt_action_param *par)
24{
25	unsigned char eui64[8];
26
27	if (!(skb_mac_header(skb) >= skb->head &&
28	      skb_mac_header(skb) + ETH_HLEN <= skb->data) &&
29	    par->fragoff != 0) {
30		par->hotdrop = true;
31		return false;
32	}
33
34	memset(eui64, 0, sizeof(eui64));
35
36	if (eth_hdr(skb)->h_proto == htons(ETH_P_IPV6)) {
37		if (ipv6_hdr(skb)->version == 0x6) {
38			memcpy(eui64, eth_hdr(skb)->h_source, 3);
39			memcpy(eui64 + 5, eth_hdr(skb)->h_source + 3, 3);
40			eui64[3] = 0xff;
41			eui64[4] = 0xfe;
42			eui64[0] ^= 0x02;
43
44			if (!memcmp(ipv6_hdr(skb)->saddr.s6_addr + 8, eui64,
45				    sizeof(eui64)))
46				return true;
47		}
48	}
49
50	return false;
51}
52
53static struct xt_match eui64_mt6_reg __read_mostly = {
54	.name		= "eui64",
55	.family		= NFPROTO_IPV6,
56	.match		= eui64_mt6,
57	.matchsize	= sizeof(int),
58	.hooks		= (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) |
59			  (1 << NF_INET_FORWARD),
60	.me		= THIS_MODULE,
61};
62
63static int __init eui64_mt6_init(void)
64{
65	return xt_register_match(&eui64_mt6_reg);
66}
67
68static void __exit eui64_mt6_exit(void)
69{
70	xt_unregister_match(&eui64_mt6_reg);
71}
72
73module_init(eui64_mt6_init);
74module_exit(eui64_mt6_exit);
75