[net-next-2.6.git] / net / ipv6 / netfilter / ip6t_ipv6header.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, const 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;
			break;
		}

		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);
Commit	Line	Data
1da177e4 LT	1	/* ipv6header match - matches IPv6 packets based
	2	on whether they contain certain headers */
	3
1ab1457c	4	/* Original idea: Brad Chapman
1da177e4 LT	5	* Rewritten by: Andras Kis-Szabo <kisza@sch.bme.hu> */
	6
	7	/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
	8	*
	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.
	12	*/
	13
	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>
	19	#include <net/ipv6.h>
	20
6709dbbb	21	#include <linux/netfilter/x_tables.h>
1da177e4 LT	22	#include <linux/netfilter_ipv6/ip6_tables.h>
	23	#include <linux/netfilter_ipv6/ip6t_ipv6header.h>
	24
	25	MODULE_LICENSE("GPL");
2ae15b64	26	MODULE_DESCRIPTION("Xtables: IPv6 header types match");
1da177e4 LT	27	MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
1da177e4 LT	28
1d93a9cb	29	static bool
4b560b44	30	ipv6header_mt6(const struct sk_buff skb, const struct xt_action_param par)
1da177e4	31	{
f7108a20	32	const struct ip6t_ipv6header_info *info = par->matchinfo;
1da177e4 LT	33	unsigned int temp;
	34	int len;
	35	u8 nexthdr;
	36	unsigned int ptr;
	37
	38	/* Make sure this isn't an evil packet */
	39
	40	/* type of the 1st exthdr */
0660e03f	41	nexthdr = ipv6_hdr(skb)->nexthdr;
1da177e4 LT	42	/* pointer to the 1st exthdr */
	43	ptr = sizeof(struct ipv6hdr);
	44	/* available length */
	45	len = skb->len - ptr;
	46	temp = 0;
	47
f0daaa65	48	while (ip6t_ext_hdr(nexthdr)) {
3cf93c96 JE	49	const struct ipv6_opt_hdr *hp;
3cf93c96 JE	50	struct ipv6_opt_hdr _hdr;
f0daaa65	51	int hdrlen;
1da177e4	52
1da177e4	53	/* No more exthdr -> evaluate */
f0daaa65	54	if (nexthdr == NEXTHDR_NONE) {
1da177e4 LT	55	temp \|= MASK_NONE;
	56	break;
	57	}
b98b4947 CP	58	/* Is there enough space for the next ext header? */
	59	if (len < (int)sizeof(struct ipv6_opt_hdr))
	60	return false;
1da177e4	61	/* ESP -> evaluate */
f0daaa65	62	if (nexthdr == NEXTHDR_ESP) {
1da177e4 LT	63	temp \|= MASK_ESP;
	64	break;
	65	}
	66
	67	hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
	68	BUG_ON(hp == NULL);
	69
	70	/* Calculate the header length */
7c4e36bc	71	if (nexthdr == NEXTHDR_FRAGMENT)
f0daaa65	72	hdrlen = 8;
7c4e36bc	73	else if (nexthdr == NEXTHDR_AUTH)
f0daaa65 YK	74	hdrlen = (hp->hdrlen + 2) << 2;
	75	else
	76	hdrlen = ipv6_optlen(hp);
1da177e4 LT	77
1da177e4 LT	78	/* set the flag */
f0daaa65 YK	79	switch (nexthdr) {
	80	case NEXTHDR_HOP:
	81	temp \|= MASK_HOPOPTS;
	82	break;
	83	case NEXTHDR_ROUTING:
	84	temp \|= MASK_ROUTING;
	85	break;
	86	case NEXTHDR_FRAGMENT:
	87	temp \|= MASK_FRAGMENT;
	88	break;
	89	case NEXTHDR_AUTH:
	90	temp \|= MASK_AH;
	91	break;
	92	case NEXTHDR_DEST:
	93	temp \|= MASK_DSTOPTS;
	94	break;
	95	default:
1d93a9cb	96	return false;
f0daaa65	97	break;
1da177e4 LT	98	}
1da177e4 LT	99
f0daaa65 YK	100	nexthdr = hp->nexthdr;
	101	len -= hdrlen;
	102	ptr += hdrlen;
1da177e4 LT	103	if (ptr > skb->len)
1da177e4 LT	104	break;
f0daaa65	105	}
1da177e4	106
7c4e36bc	107	if (nexthdr != NEXTHDR_NONE && nexthdr != NEXTHDR_ESP)
1da177e4 LT	108	temp \|= MASK_PROTO;
	109
	110	if (info->modeflag)
	111	return !((temp ^ info->matchflags ^ info->invflags)
	112	& info->matchflags);
	113	else {
	114	if (info->invflags)
	115	return temp != info->matchflags;
	116	else
	117	return temp == info->matchflags;
	118	}
	119	}
	120
b0f38452	121	static int ipv6header_mt6_check(const struct xt_mtchk_param *par)
1da177e4	122	{
9b4fce7a	123	const struct ip6t_ipv6header_info *info = par->matchinfo;
1da177e4	124
1da177e4	125	/* invflags is 0 or 0xff in hard mode */
f0daaa65 YK	126	if ((!info->modeflag) && info->invflags != 0x00 &&
f0daaa65 YK	127	info->invflags != 0xFF)
bd414ee6	128	return -EINVAL;
1da177e4	129
bd414ee6	130	return 0;
1da177e4 LT	131	}
1da177e4 LT	132
d3c5ee6d	133	static struct xt_match ipv6header_mt6_reg __read_mostly = {
1da177e4	134	.name = "ipv6header",
ee999d8b	135	.family = NFPROTO_IPV6,
d3c5ee6d	136	.match = ipv6header_mt6,
7f939713	137	.matchsize = sizeof(struct ip6t_ipv6header_info),
d3c5ee6d	138	.checkentry = ipv6header_mt6_check,
1da177e4 LT	139	.destroy = NULL,
	140	.me = THIS_MODULE,
	141	};
	142
d3c5ee6d	143	static int __init ipv6header_mt6_init(void)
1da177e4	144	{
d3c5ee6d	145	return xt_register_match(&ipv6header_mt6_reg);
1da177e4 LT	146	}
1da177e4 LT	147
d3c5ee6d	148	static void __exit ipv6header_mt6_exit(void)
1da177e4	149	{
d3c5ee6d	150	xt_unregister_match(&ipv6header_mt6_reg);
1da177e4 LT	151	}
1da177e4 LT	152
d3c5ee6d JE	153	module_init(ipv6header_mt6_init);
d3c5ee6d JE	154	module_exit(ipv6header_mt6_exit);