[net-next-2.6.git] / net / ipv6 / netfilter / ip6t_ah.c

/* Kernel module to match AH parameters. */

/* (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/ip.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_ah.h>

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

/* Returns 1 if the spi is matched by the range, 0 otherwise */
static inline bool
spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
{
	bool r;

	pr_debug("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",
		 invert ? '!' : ' ', min, spi, max);
	r = (spi >= min && spi <= max) ^ invert;
	pr_debug(" result %s\n", r ? "PASS" : "FAILED");
	return r;
}

static bool
ah_mt6(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, bool *hotdrop)
{
	struct ip_auth_hdr _ah;
	const struct ip_auth_hdr *ah;
	const struct ip6t_ah *ahinfo = matchinfo;
	unsigned int ptr;
	unsigned int hdrlen = 0;
	int err;

	err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL);
	if (err < 0) {
		if (err != -ENOENT)
			*hotdrop = true;
		return false;
	}

	ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
	if (ah == NULL) {
		*hotdrop = true;
		return false;
	}

	hdrlen = (ah->hdrlen + 2) << 2;

	pr_debug("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
	pr_debug("RES %04X ", ah->reserved);
	pr_debug("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));

	pr_debug("IPv6 AH spi %02X ",
		 spi_match(ahinfo->spis[0], ahinfo->spis[1],
			   ntohl(ah->spi),
			   !!(ahinfo->invflags & IP6T_AH_INV_SPI)));
	pr_debug("len %02X %04X %02X ",
		 ahinfo->hdrlen, hdrlen,
		 (!ahinfo->hdrlen ||
		  (ahinfo->hdrlen == hdrlen) ^
		  !!(ahinfo->invflags & IP6T_AH_INV_LEN)));
	pr_debug("res %02X %04X %02X\n",
		 ahinfo->hdrres, ah->reserved,
		 !(ahinfo->hdrres && ah->reserved));

	return (ah != NULL)
	       &&
	       spi_match(ahinfo->spis[0], ahinfo->spis[1],
			 ntohl(ah->spi),
			 !!(ahinfo->invflags & IP6T_AH_INV_SPI))
	       &&
	       (!ahinfo->hdrlen ||
		(ahinfo->hdrlen == hdrlen) ^
		!!(ahinfo->invflags & IP6T_AH_INV_LEN))
	       &&
	       !(ahinfo->hdrres && ah->reserved);
}

/* Called when user tries to insert an entry of this type. */
static bool
ah_mt6_check(const char *tablename, const void *entry,
             const struct xt_match *match, void *matchinfo,
             unsigned int hook_mask)
{
	const struct ip6t_ah *ahinfo = matchinfo;

	if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
		pr_debug("ip6t_ah: unknown flags %X\n", ahinfo->invflags);
		return false;
	}
	return true;
}

static struct xt_match ah_mt6_reg __read_mostly = {
	.name		= "ah",
	.family		= AF_INET6,
	.match		= ah_mt6,
	.matchsize	= sizeof(struct ip6t_ah),
	.checkentry	= ah_mt6_check,
	.me		= THIS_MODULE,
};

static int __init ah_mt6_init(void)
{
	return xt_register_match(&ah_mt6_reg);
}

static void __exit ah_mt6_exit(void)
{
	xt_unregister_match(&ah_mt6_reg);
}

module_init(ah_mt6_init);
module_exit(ah_mt6_exit);
Commit	Line	Data
1da177e4 LT	1	/* Kernel module to match AH parameters. */
	2
	3	/* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/skbuff.h>
14c85021	12	#include <linux/ip.h>
1da177e4 LT	13	#include <linux/ipv6.h>
	14	#include <linux/types.h>
	15	#include <net/checksum.h>
	16	#include <net/ipv6.h>
	17
6709dbbb	18	#include <linux/netfilter/x_tables.h>
1da177e4 LT	19	#include <linux/netfilter_ipv6/ip6_tables.h>
	20	#include <linux/netfilter_ipv6/ip6t_ah.h>
	21
	22	MODULE_LICENSE("GPL");
	23	MODULE_DESCRIPTION("IPv6 AH match");
	24	MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
	25
1da177e4	26	/* Returns 1 if the spi is matched by the range, 0 otherwise */
1d93a9cb JE	27	static inline bool
1d93a9cb JE	28	spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
1da177e4	29	{
1d93a9cb	30	bool r;
0d53778e PM	31
	32	pr_debug("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",
	33	invert ? '!' : ' ', min, spi, max);
1da177e4	34	r = (spi >= min && spi <= max) ^ invert;
0d53778e	35	pr_debug(" result %s\n", r ? "PASS" : "FAILED");
1da177e4 LT	36	return r;
	37	}
	38
1d93a9cb	39	static bool
d3c5ee6d JE	40	ah_mt6(const struct sk_buff skb, const struct net_device in,
	41	const struct net_device out, const struct xt_match match,
	42	const void matchinfo, int offset, unsigned int protoff, bool hotdrop)
1da177e4	43	{
a47362a2 JE	44	struct ip_auth_hdr _ah;
a47362a2 JE	45	const struct ip_auth_hdr *ah;
1da177e4	46	const struct ip6t_ah *ahinfo = matchinfo;
1da177e4 LT	47	unsigned int ptr;
1da177e4 LT	48	unsigned int hdrlen = 0;
6d381634	49	int err;
1da177e4	50
6d381634 PM	51	err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL);
	52	if (err < 0) {
	53	if (err != -ENOENT)
cff533ac	54	*hotdrop = true;
1d93a9cb	55	return false;
6d381634	56	}
1da177e4	57
e674d0f3 YK	58	ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
e674d0f3 YK	59	if (ah == NULL) {
cff533ac	60	*hotdrop = true;
1d93a9cb	61	return false;
1da177e4 LT	62	}
1da177e4 LT	63
e674d0f3	64	hdrlen = (ah->hdrlen + 2) << 2;
1da177e4	65
0d53778e PM	66	pr_debug("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
	67	pr_debug("RES %04X ", ah->reserved);
	68	pr_debug("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));
	69
	70	pr_debug("IPv6 AH spi %02X ",
	71	spi_match(ahinfo->spis[0], ahinfo->spis[1],
	72	ntohl(ah->spi),
	73	!!(ahinfo->invflags & IP6T_AH_INV_SPI)));
	74	pr_debug("len %02X %04X %02X ",
	75	ahinfo->hdrlen, hdrlen,
	76	(!ahinfo->hdrlen \|\|
	77	(ahinfo->hdrlen == hdrlen) ^
	78	!!(ahinfo->invflags & IP6T_AH_INV_LEN)));
	79	pr_debug("res %02X %04X %02X\n",
	80	ahinfo->hdrres, ah->reserved,
	81	!(ahinfo->hdrres && ah->reserved));
1da177e4 LT	82
	83	return (ah != NULL)
	84	&&
7c4e36bc JE	85	spi_match(ahinfo->spis[0], ahinfo->spis[1],
	86	ntohl(ah->spi),
	87	!!(ahinfo->invflags & IP6T_AH_INV_SPI))
1da177e4 LT	88	&&
1da177e4 LT	89	(!ahinfo->hdrlen \|\|
1ab1457c YH	90	(ahinfo->hdrlen == hdrlen) ^
1ab1457c YH	91	!!(ahinfo->invflags & IP6T_AH_INV_LEN))
1da177e4 LT	92	&&
	93	!(ahinfo->hdrres && ah->reserved);
	94	}
	95
	96	/* Called when user tries to insert an entry of this type. */
ccb79bdc	97	static bool
d3c5ee6d JE	98	ah_mt6_check(const char tablename, const void entry,
	99	const struct xt_match match, void matchinfo,
	100	unsigned int hook_mask)
1da177e4 LT	101	{
	102	const struct ip6t_ah *ahinfo = matchinfo;
	103
1da177e4	104	if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
0d53778e	105	pr_debug("ip6t_ah: unknown flags %X\n", ahinfo->invflags);
ccb79bdc	106	return false;
1da177e4	107	}
ccb79bdc	108	return true;
1da177e4 LT	109	}
1da177e4 LT	110
d3c5ee6d	111	static struct xt_match ah_mt6_reg __read_mostly = {
1da177e4	112	.name = "ah",
6709dbbb	113	.family = AF_INET6,
d3c5ee6d	114	.match = ah_mt6,
7f939713	115	.matchsize = sizeof(struct ip6t_ah),
d3c5ee6d	116	.checkentry = ah_mt6_check,
1da177e4 LT	117	.me = THIS_MODULE,
	118	};
	119
d3c5ee6d	120	static int __init ah_mt6_init(void)
1da177e4	121	{
d3c5ee6d	122	return xt_register_match(&ah_mt6_reg);
1da177e4 LT	123	}
1da177e4 LT	124
d3c5ee6d	125	static void __exit ah_mt6_exit(void)
1da177e4	126	{
d3c5ee6d	127	xt_unregister_match(&ah_mt6_reg);
1da177e4 LT	128	}
1da177e4 LT	129
d3c5ee6d JE	130	module_init(ah_mt6_init);
d3c5ee6d JE	131	module_exit(ah_mt6_exit);