mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-25 02:09:42 +00:00
![Fabian Frederick](/assets/img/avatar_default.png)
Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: David S. Miller <davem@davemloft.net>
153 lines
3.5 KiB
C
153 lines
3.5 KiB
C
/* ipv6header match - matches IPv6 packets based
|
|
on whether they contain certain headers */
|
|
|
|
/* Original idea: Brad Chapman
|
|
* Rewritten by: Andras Kis-Szabo <kisza@sch.bme.hu> */
|
|
|
|
/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/ipv6.h>
|
|
#include <linux/types.h>
|
|
#include <net/checksum.h>
|
|
#include <net/ipv6.h>
|
|
|
|
#include <linux/netfilter/x_tables.h>
|
|
#include <linux/netfilter_ipv6/ip6_tables.h>
|
|
#include <linux/netfilter_ipv6/ip6t_ipv6header.h>
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("Xtables: IPv6 header types match");
|
|
MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
|
|
|
|
static bool
|
|
ipv6header_mt6(const struct sk_buff *skb, struct xt_action_param *par)
|
|
{
|
|
const struct ip6t_ipv6header_info *info = par->matchinfo;
|
|
unsigned int temp;
|
|
int len;
|
|
u8 nexthdr;
|
|
unsigned int ptr;
|
|
|
|
/* Make sure this isn't an evil packet */
|
|
|
|
/* type of the 1st exthdr */
|
|
nexthdr = ipv6_hdr(skb)->nexthdr;
|
|
/* pointer to the 1st exthdr */
|
|
ptr = sizeof(struct ipv6hdr);
|
|
/* available length */
|
|
len = skb->len - ptr;
|
|
temp = 0;
|
|
|
|
while (ip6t_ext_hdr(nexthdr)) {
|
|
const struct ipv6_opt_hdr *hp;
|
|
struct ipv6_opt_hdr _hdr;
|
|
int hdrlen;
|
|
|
|
/* No more exthdr -> evaluate */
|
|
if (nexthdr == NEXTHDR_NONE) {
|
|
temp |= MASK_NONE;
|
|
break;
|
|
}
|
|
/* Is there enough space for the next ext header? */
|
|
if (len < (int)sizeof(struct ipv6_opt_hdr))
|
|
return false;
|
|
/* ESP -> evaluate */
|
|
if (nexthdr == NEXTHDR_ESP) {
|
|
temp |= MASK_ESP;
|
|
break;
|
|
}
|
|
|
|
hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
|
|
BUG_ON(hp == NULL);
|
|
|
|
/* Calculate the header length */
|
|
if (nexthdr == NEXTHDR_FRAGMENT)
|
|
hdrlen = 8;
|
|
else if (nexthdr == NEXTHDR_AUTH)
|
|
hdrlen = (hp->hdrlen + 2) << 2;
|
|
else
|
|
hdrlen = ipv6_optlen(hp);
|
|
|
|
/* set the flag */
|
|
switch (nexthdr) {
|
|
case NEXTHDR_HOP:
|
|
temp |= MASK_HOPOPTS;
|
|
break;
|
|
case NEXTHDR_ROUTING:
|
|
temp |= MASK_ROUTING;
|
|
break;
|
|
case NEXTHDR_FRAGMENT:
|
|
temp |= MASK_FRAGMENT;
|
|
break;
|
|
case NEXTHDR_AUTH:
|
|
temp |= MASK_AH;
|
|
break;
|
|
case NEXTHDR_DEST:
|
|
temp |= MASK_DSTOPTS;
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
nexthdr = hp->nexthdr;
|
|
len -= hdrlen;
|
|
ptr += hdrlen;
|
|
if (ptr > skb->len)
|
|
break;
|
|
}
|
|
|
|
if (nexthdr != NEXTHDR_NONE && nexthdr != NEXTHDR_ESP)
|
|
temp |= MASK_PROTO;
|
|
|
|
if (info->modeflag)
|
|
return !((temp ^ info->matchflags ^ info->invflags)
|
|
& info->matchflags);
|
|
else {
|
|
if (info->invflags)
|
|
return temp != info->matchflags;
|
|
else
|
|
return temp == info->matchflags;
|
|
}
|
|
}
|
|
|
|
static int ipv6header_mt6_check(const struct xt_mtchk_param *par)
|
|
{
|
|
const struct ip6t_ipv6header_info *info = par->matchinfo;
|
|
|
|
/* invflags is 0 or 0xff in hard mode */
|
|
if ((!info->modeflag) && info->invflags != 0x00 &&
|
|
info->invflags != 0xFF)
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct xt_match ipv6header_mt6_reg __read_mostly = {
|
|
.name = "ipv6header",
|
|
.family = NFPROTO_IPV6,
|
|
.match = ipv6header_mt6,
|
|
.matchsize = sizeof(struct ip6t_ipv6header_info),
|
|
.checkentry = ipv6header_mt6_check,
|
|
.destroy = NULL,
|
|
.me = THIS_MODULE,
|
|
};
|
|
|
|
static int __init ipv6header_mt6_init(void)
|
|
{
|
|
return xt_register_match(&ipv6header_mt6_reg);
|
|
}
|
|
|
|
static void __exit ipv6header_mt6_exit(void)
|
|
{
|
|
xt_unregister_match(&ipv6header_mt6_reg);
|
|
}
|
|
|
|
module_init(ipv6header_mt6_init);
|
|
module_exit(ipv6header_mt6_exit);
|