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 net_device *in,
31 const struct net_device *out, const struct xt_match *match,
32 const void *matchinfo, int offset, unsigned int protoff,
35 const struct ip6t_ipv6header_info *info = matchinfo;
41 /* Make sure this isn't an evil packet */
43 /* type of the 1st exthdr */
44 nexthdr = ipv6_hdr(skb)->nexthdr;
45 /* pointer to the 1st exthdr */
46 ptr = sizeof(struct ipv6hdr);
47 /* available length */
51 while (ip6t_ext_hdr(nexthdr)) {
52 struct ipv6_opt_hdr _hdr, *hp;
55 /* Is there enough space for the next ext header? */
56 if (len < (int)sizeof(struct ipv6_opt_hdr))
58 /* No more exthdr -> evaluate */
59 if (nexthdr == NEXTHDR_NONE) {
64 if (nexthdr == NEXTHDR_ESP) {
69 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
72 /* Calculate the header length */
73 if (nexthdr == NEXTHDR_FRAGMENT)
75 else if (nexthdr == NEXTHDR_AUTH)
76 hdrlen = (hp->hdrlen + 2) << 2;
78 hdrlen = ipv6_optlen(hp);
88 case NEXTHDR_FRAGMENT:
89 temp |= MASK_FRAGMENT;
102 nexthdr = hp->nexthdr;
109 if (nexthdr != NEXTHDR_NONE && nexthdr != NEXTHDR_ESP)
113 return !((temp ^ info->matchflags ^ info->invflags)
117 return temp != info->matchflags;
119 return temp == info->matchflags;
124 ipv6header_mt6_check(const char *tablename, const void *ip,
125 const struct xt_match *match, void *matchinfo,
126 unsigned int hook_mask)
128 const struct ip6t_ipv6header_info *info = matchinfo;
130 /* invflags is 0 or 0xff in hard mode */
131 if ((!info->modeflag) && info->invflags != 0x00 &&
132 info->invflags != 0xFF)
138 static struct xt_match ipv6header_mt6_reg __read_mostly = {
139 .name = "ipv6header",
141 .match = ipv6header_mt6,
142 .matchsize = sizeof(struct ip6t_ipv6header_info),
143 .checkentry = ipv6header_mt6_check,
148 static int __init ipv6header_mt6_init(void)
150 return xt_register_match(&ipv6header_mt6_reg);
153 static void __exit ipv6header_mt6_exit(void)
155 xt_unregister_match(&ipv6header_mt6_reg);
158 module_init(ipv6header_mt6_init);
159 module_exit(ipv6header_mt6_exit);