1 /* ipv6header match - matches IPv6 packets based
2 on whether they contain certain headers */
4 /* Original idea: Brad Chapman
5 * Rewritten by: Andras Kis-Szabo <kisza@sch.bme.hu> */
7 /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/ipv6.h>
17 #include <linux/types.h>
18 #include <net/checksum.h>
21 #include <linux/netfilter/x_tables.h>
22 #include <linux/netfilter_ipv6/ip6_tables.h>
23 #include <linux/netfilter_ipv6/ip6t_ipv6header.h>
25 MODULE_LICENSE("GPL");
26 MODULE_DESCRIPTION("Xtables: IPv6 header types match");
27 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
30 ipv6header_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
32 const struct ip6t_ipv6header_info *info = par->matchinfo;
38 /* Make sure this isn't an evil packet */
40 /* type of the 1st exthdr */
41 nexthdr = ipv6_hdr(skb)->nexthdr;
42 /* pointer to the 1st exthdr */
43 ptr = sizeof(struct ipv6hdr);
44 /* available length */
48 while (ip6t_ext_hdr(nexthdr)) {
49 const struct ipv6_opt_hdr *hp;
50 struct ipv6_opt_hdr _hdr;
53 /* No more exthdr -> evaluate */
54 if (nexthdr == NEXTHDR_NONE) {
58 /* Is there enough space for the next ext header? */
59 if (len < (int)sizeof(struct ipv6_opt_hdr))
62 if (nexthdr == NEXTHDR_ESP) {
67 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
70 /* Calculate the header length */
71 if (nexthdr == NEXTHDR_FRAGMENT)
73 else if (nexthdr == NEXTHDR_AUTH)
74 hdrlen = (hp->hdrlen + 2) << 2;
76 hdrlen = ipv6_optlen(hp);
86 case NEXTHDR_FRAGMENT:
87 temp |= MASK_FRAGMENT;
100 nexthdr = hp->nexthdr;
107 if (nexthdr != NEXTHDR_NONE && nexthdr != NEXTHDR_ESP)
111 return !((temp ^ info->matchflags ^ info->invflags)
115 return temp != info->matchflags;
117 return temp == info->matchflags;
121 static bool ipv6header_mt6_check(const struct xt_mtchk_param *par)
123 const struct ip6t_ipv6header_info *info = par->matchinfo;
125 /* invflags is 0 or 0xff in hard mode */
126 if ((!info->modeflag) && info->invflags != 0x00 &&
127 info->invflags != 0xFF)
133 static struct xt_match ipv6header_mt6_reg __read_mostly = {
134 .name = "ipv6header",
135 .family = NFPROTO_IPV6,
136 .match = ipv6header_mt6,
137 .matchsize = sizeof(struct ip6t_ipv6header_info),
138 .checkentry = ipv6header_mt6_check,
143 static int __init ipv6header_mt6_init(void)
145 return xt_register_match(&ipv6header_mt6_reg);
148 static void __exit ipv6header_mt6_exit(void)
150 xt_unregister_match(&ipv6header_mt6_reg);
153 module_init(ipv6header_mt6_init);
154 module_exit(ipv6header_mt6_exit);