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
18 MODULE_DESCRIPTION("Xtables: IPv6 EUI64 address match");
19 MODULE_LICENSE("GPL");
20 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
21
22 static bool
eui64_mt6(const struct sk_buff * skb,const struct xt_match_param * par)23 eui64_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
24 {
25 unsigned char eui64[8];
26 int i = 0;
27
28 if (!(skb_mac_header(skb) >= skb->head &&
29 skb_mac_header(skb) + ETH_HLEN <= skb->data) &&
30 par->fragoff != 0) {
31 *par->hotdrop = true;
32 return false;
33 }
34
35 memset(eui64, 0, sizeof(eui64));
36
37 if (eth_hdr(skb)->h_proto == htons(ETH_P_IPV6)) {
38 if (ipv6_hdr(skb)->version == 0x6) {
39 memcpy(eui64, eth_hdr(skb)->h_source, 3);
40 memcpy(eui64 + 5, eth_hdr(skb)->h_source + 3, 3);
41 eui64[3] = 0xff;
42 eui64[4] = 0xfe;
43 eui64[0] ^= 0x02;
44
45 i = 0;
46 while (ipv6_hdr(skb)->saddr.s6_addr[8 + i] == eui64[i]
47 && i < 8)
48 i++;
49
50 if (i == 8)
51 return true;
52 }
53 }
54
55 return false;
56 }
57
58 static struct xt_match eui64_mt6_reg __read_mostly = {
59 .name = "eui64",
60 .family = NFPROTO_IPV6,
61 .match = eui64_mt6,
62 .matchsize = sizeof(int),
63 .hooks = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) |
64 (1 << NF_INET_FORWARD),
65 .me = THIS_MODULE,
66 };
67
eui64_mt6_init(void)68 static int __init eui64_mt6_init(void)
69 {
70 return xt_register_match(&eui64_mt6_reg);
71 }
72
eui64_mt6_exit(void)73 static void __exit eui64_mt6_exit(void)
74 {
75 xt_unregister_match(&eui64_mt6_reg);
76 }
77
78 module_init(eui64_mt6_init);
79 module_exit(eui64_mt6_exit);
80