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_ipv6/ip6_tables.h>
22 #include <linux/netfilter_ipv6/ip6t_ipv6header.h>
24 MODULE_LICENSE("GPL");
25 MODULE_DESCRIPTION("IPv6 headers match");
26 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
29 ipv6header_match(const struct sk_buff
*skb
,
30 const struct net_device
*in
,
31 const struct net_device
*out
,
32 const void *matchinfo
,
37 const struct ip6t_ipv6header_info
*info
= matchinfo
;
43 /* Make sure this isn't an evil packet */
45 /* type of the 1st exthdr */
46 nexthdr
= skb
->nh
.ipv6h
->nexthdr
;
47 /* pointer to the 1st exthdr */
48 ptr
= sizeof(struct ipv6hdr
);
49 /* available length */
53 while (ip6t_ext_hdr(nexthdr
)) {
54 struct ipv6_opt_hdr _hdr
, *hp
;
57 /* Is there enough space for the next ext header? */
58 if (len
< (int)sizeof(struct ipv6_opt_hdr
))
60 /* No more exthdr -> evaluate */
61 if (nexthdr
== NEXTHDR_NONE
) {
66 if (nexthdr
== NEXTHDR_ESP
) {
71 hp
= skb_header_pointer(skb
, ptr
, sizeof(_hdr
), &_hdr
);
74 /* Calculate the header length */
75 if (nexthdr
== NEXTHDR_FRAGMENT
) {
77 } else if (nexthdr
== NEXTHDR_AUTH
)
78 hdrlen
= (hp
->hdrlen
+2)<<2;
80 hdrlen
= ipv6_optlen(hp
);
90 case NEXTHDR_FRAGMENT
:
91 temp
|= MASK_FRAGMENT
;
104 nexthdr
= hp
->nexthdr
;
111 if ( (nexthdr
!= NEXTHDR_NONE
) && (nexthdr
!= NEXTHDR_ESP
) )
115 return !((temp
^ info
->matchflags
^ info
->invflags
)
119 return temp
!= info
->matchflags
;
121 return temp
== info
->matchflags
;
126 ipv6header_checkentry(const char *tablename
,
127 const struct ip6t_ip6
*ip
,
129 unsigned int matchsize
,
130 unsigned int hook_mask
)
132 const struct ip6t_ipv6header_info
*info
= matchinfo
;
134 /* Check for obvious errors */
135 /* This match is valid in all hooks! */
136 if (matchsize
!= IP6T_ALIGN(sizeof(struct ip6t_ipv6header_info
)))
139 /* invflags is 0 or 0xff in hard mode */
140 if ((!info
->modeflag
) && info
->invflags
!= 0x00
141 && info
->invflags
!= 0xFF)
147 static struct ip6t_match ip6t_ipv6header_match
= {
148 .name
= "ipv6header",
149 .match
= &ipv6header_match
,
150 .checkentry
= &ipv6header_checkentry
,
155 static int __init
ipv6header_init(void)
157 return ip6t_register_match(&ip6t_ipv6header_match
);
160 static void __exit
ipv6header_exit(void)
162 ip6t_unregister_match(&ip6t_ipv6header_match
);
165 module_init(ipv6header_init
);
166 module_exit(ipv6header_exit
);