[mirror_ubuntu-hirsute-kernel.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_ipv6/ip6_tables.h>
#include <linux/netfilter_ipv6/ip6t_ipv6header.h>

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IPv6 headers match");
MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");

static int
ipv6header_match(const struct sk_buff *skb,
		 const struct net_device *in,
		 const struct net_device *out,
		 const struct xt_match *match,
		 const void *matchinfo,
		 int offset,
		 unsigned int protoff,
		 int *hotdrop)
{
	const struct ip6t_ipv6header_info *info = 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 = skb->nh.ipv6h->nexthdr;
	/* pointer to the 1st exthdr */
	ptr = sizeof(struct ipv6hdr);
	/* available length */
	len = skb->len - ptr;
	temp = 0;

	while (ip6t_ext_hdr(nexthdr)) {
		struct ipv6_opt_hdr _hdr, *hp;
		int hdrlen;

		/* Is there enough space for the next ext header? */
		if (len < (int)sizeof(struct ipv6_opt_hdr))
			return 0;
		/* No more exthdr -> evaluate */
		if (nexthdr == NEXTHDR_NONE) {
			temp |= MASK_NONE;
			break;
		}
		/* 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 0;
			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_checkentry(const char *tablename,
		      const void *ip,
		      const struct xt_match *match,
		      void *matchinfo,
		      unsigned int hook_mask)
{
	const struct ip6t_ipv6header_info *info = matchinfo;

	/* invflags is 0 or 0xff in hard mode */
	if ((!info->modeflag) && info->invflags != 0x00 &&
	    info->invflags != 0xFF)
		return 0;

	return 1;
}

static struct ip6t_match ip6t_ipv6header_match = {
	.name		= "ipv6header",
	.match		= &ipv6header_match,
	.matchsize	= sizeof(struct ip6t_ipv6header_info),
	.checkentry	= &ipv6header_checkentry,
	.destroy	= NULL,
	.me		= THIS_MODULE,
};

static int __init ipv6header_init(void)
{
	return ip6t_register_match(&ip6t_ipv6header_match);
}

static void __exit ipv6header_exit(void)
{
	ip6t_unregister_match(&ip6t_ipv6header_match);
}

module_init(ipv6header_init);
module_exit(ipv6header_exit);
Commit	Line	Data
1da177e4 LT	1	/* ipv6header match - matches IPv6 packets based
	2	on whether they contain certain headers */
	3
	4	/* Original idea: Brad Chapman
	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
	21	#include <linux/netfilter_ipv6/ip6_tables.h>
	22	#include <linux/netfilter_ipv6/ip6t_ipv6header.h>
	23
	24	MODULE_LICENSE("GPL");
	25	MODULE_DESCRIPTION("IPv6 headers match");
	26	MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
	27
	28	static int
	29	ipv6header_match(const struct sk_buff *skb,
	30	const struct net_device *in,
	31	const struct net_device *out,
c4986734	32	const struct xt_match *match,
1da177e4 LT	33	const void *matchinfo,
	34	int offset,
	35	unsigned int protoff,
	36	int *hotdrop)
	37	{
	38	const struct ip6t_ipv6header_info *info = matchinfo;
	39	unsigned int temp;
	40	int len;
	41	u8 nexthdr;
	42	unsigned int ptr;
	43
	44	/* Make sure this isn't an evil packet */
	45
	46	/* type of the 1st exthdr */
	47	nexthdr = skb->nh.ipv6h->nexthdr;
	48	/* pointer to the 1st exthdr */
	49	ptr = sizeof(struct ipv6hdr);
	50	/* available length */
	51	len = skb->len - ptr;
	52	temp = 0;
	53
f0daaa65	54	while (ip6t_ext_hdr(nexthdr)) {
1da177e4	55	struct ipv6_opt_hdr _hdr, *hp;
f0daaa65	56	int hdrlen;
1da177e4 LT	57
1da177e4 LT	58	/* Is there enough space for the next ext header? */
f0daaa65 YK	59	if (len < (int)sizeof(struct ipv6_opt_hdr))
f0daaa65 YK	60	return 0;
1da177e4	61	/* No more exthdr -> evaluate */
f0daaa65	62	if (nexthdr == NEXTHDR_NONE) {
1da177e4 LT	63	temp \|= MASK_NONE;
	64	break;
	65	}
	66	/* ESP -> evaluate */
f0daaa65	67	if (nexthdr == NEXTHDR_ESP) {
1da177e4 LT	68	temp \|= MASK_ESP;
	69	break;
	70	}
	71
	72	hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
	73	BUG_ON(hp == NULL);
	74
	75	/* Calculate the header length */
f0daaa65 YK	76	if (nexthdr == NEXTHDR_FRAGMENT) {
	77	hdrlen = 8;
	78	} else if (nexthdr == NEXTHDR_AUTH)
	79	hdrlen = (hp->hdrlen + 2) << 2;
	80	else
	81	hdrlen = ipv6_optlen(hp);
1da177e4 LT	82
1da177e4 LT	83	/* set the flag */
f0daaa65 YK	84	switch (nexthdr) {
	85	case NEXTHDR_HOP:
	86	temp \|= MASK_HOPOPTS;
	87	break;
	88	case NEXTHDR_ROUTING:
	89	temp \|= MASK_ROUTING;
	90	break;
	91	case NEXTHDR_FRAGMENT:
	92	temp \|= MASK_FRAGMENT;
	93	break;
	94	case NEXTHDR_AUTH:
	95	temp \|= MASK_AH;
	96	break;
	97	case NEXTHDR_DEST:
	98	temp \|= MASK_DSTOPTS;
	99	break;
	100	default:
	101	return 0;
	102	break;
1da177e4 LT	103	}
1da177e4 LT	104
f0daaa65 YK	105	nexthdr = hp->nexthdr;
	106	len -= hdrlen;
	107	ptr += hdrlen;
1da177e4 LT	108	if (ptr > skb->len)
1da177e4 LT	109	break;
f0daaa65	110	}
1da177e4	111
f0daaa65	112	if ((nexthdr != NEXTHDR_NONE) && (nexthdr != NEXTHDR_ESP))
1da177e4 LT	113	temp \|= MASK_PROTO;
	114
	115	if (info->modeflag)
	116	return !((temp ^ info->matchflags ^ info->invflags)
	117	& info->matchflags);
	118	else {
	119	if (info->invflags)
	120	return temp != info->matchflags;
	121	else
	122	return temp == info->matchflags;
	123	}
	124	}
	125
	126	static int
	127	ipv6header_checkentry(const char *tablename,
2e4e6a17	128	const void *ip,
c4986734	129	const struct xt_match *match,
1da177e4	130	void *matchinfo,
1da177e4 LT	131	unsigned int hook_mask)
	132	{
	133	const struct ip6t_ipv6header_info *info = matchinfo;
	134
1da177e4	135	/* invflags is 0 or 0xff in hard mode */
f0daaa65 YK	136	if ((!info->modeflag) && info->invflags != 0x00 &&
f0daaa65 YK	137	info->invflags != 0xFF)
1da177e4 LT	138	return 0;
	139
	140	return 1;
	141	}
	142
	143	static struct ip6t_match ip6t_ipv6header_match = {
	144	.name = "ipv6header",
	145	.match = &ipv6header_match,
7f939713	146	.matchsize = sizeof(struct ip6t_ipv6header_info),
1da177e4 LT	147	.checkentry = &ipv6header_checkentry,
	148	.destroy = NULL,
	149	.me = THIS_MODULE,
	150	};
	151
f0daaa65	152	static int __init ipv6header_init(void)
1da177e4 LT	153	{
	154	return ip6t_register_match(&ip6t_ipv6header_match);
	155	}
	156
	157	static void __exit ipv6header_exit(void)
	158	{
	159	ip6t_unregister_match(&ip6t_ipv6header_match);
	160	}
	161
	162	module_init(ipv6header_init);
	163	module_exit(ipv6header_exit);