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("IPv6 EUI64 address checking match");
19MODULE_LICENSE("GPL");
20MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
21
22static int
23match(const struct sk_buff *skb,
24      const struct net_device *in,
25      const struct net_device *out,
26      const struct xt_match *match,
27      const void *matchinfo,
28      int offset,
29      unsigned int protoff,
30      int *hotdrop)
31{
32	unsigned char eui64[8];
33	int i = 0;
34
35	if (!(skb_mac_header(skb) >= skb->head &&
36	      (skb_mac_header(skb) + ETH_HLEN) <= skb->data) &&
37	    offset != 0) {
38		*hotdrop = 1;
39		return 0;
40	}
41
42	memset(eui64, 0, sizeof(eui64));
43
44	if (eth_hdr(skb)->h_proto == htons(ETH_P_IPV6)) {
45		if (ipv6_hdr(skb)->version == 0x6) {
46			memcpy(eui64, eth_hdr(skb)->h_source, 3);
47			memcpy(eui64 + 5, eth_hdr(skb)->h_source + 3, 3);
48			eui64[3] = 0xff;
49			eui64[4] = 0xfe;
50			eui64[0] |= 0x02;
51
52			i = 0;
53			while ((ipv6_hdr(skb)->saddr.s6_addr[8 + i] == eui64[i])
54			       && (i < 8))
55				i++;
56
57			if (i == 8)
58				return 1;
59		}
60	}
61
62	return 0;
63}
64
65static struct xt_match eui64_match = {
66	.name		= "eui64",
67	.family		= AF_INET6,
68	.match		= match,
69	.matchsize	= sizeof(int),
70	.hooks		= (1 << NF_IP6_PRE_ROUTING) | (1 << NF_IP6_LOCAL_IN) |
71			  (1 << NF_IP6_FORWARD),
72	.me		= THIS_MODULE,
73};
74
75static int __init ip6t_eui64_init(void)
76{
77	return xt_register_match(&eui64_match);
78}
79
80static void __exit ip6t_eui64_fini(void)
81{
82	xt_unregister_match(&eui64_match);
83}
84
85module_init(ip6t_eui64_init);
86module_exit(ip6t_eui64_fini);
87