[deliverable/linux.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_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>");

#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif

/* Returns 1 if the spi is matched by the range, 0 otherwise */
static inline int
spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
{
	int r=0;
	DEBUGP("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
	       min,spi,max);
	r = (spi >= min && spi <= max) ^ invert;
	DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
	return r;
}

static int
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)
{
	struct ip_auth_hdr *ah, _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 = 1;
		return 0;
	}

	ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
	if (ah == NULL) {
		*hotdrop = 1;
		return 0;
	}

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

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

	DEBUGP("IPv6 AH spi %02X ",
	       (spi_match(ahinfo->spis[0], ahinfo->spis[1],
	                  ntohl(ah->spi),
	                  !!(ahinfo->invflags & IP6T_AH_INV_SPI))));
	DEBUGP("len %02X %04X %02X ",
	       ahinfo->hdrlen, hdrlen,
	       (!ahinfo->hdrlen ||
	        (ahinfo->hdrlen == hdrlen) ^
	        !!(ahinfo->invflags & IP6T_AH_INV_LEN)));
	DEBUGP("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 int
checkentry(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) {
		DEBUGP("ip6t_ah: unknown flags %X\n", ahinfo->invflags);
		return 0;
	}
	return 1;
}

static struct ip6t_match ah_match = {
	.name		= "ah",
	.match		= match,
	.matchsize	= sizeof(struct ip6t_ah),
	.checkentry	= checkentry,
	.me		= THIS_MODULE,
};

static int __init ip6t_ah_init(void)
{
	return ip6t_register_match(&ah_match);
}

static void __exit ip6t_ah_fini(void)
{
	ip6t_unregister_match(&ah_match);
}

module_init(ip6t_ah_init);
module_exit(ip6t_ah_fini);
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
	18	#include <linux/netfilter_ipv6/ip6_tables.h>
	19	#include <linux/netfilter_ipv6/ip6t_ah.h>
	20
	21	MODULE_LICENSE("GPL");
	22	MODULE_DESCRIPTION("IPv6 AH match");
	23	MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
	24
	25	#if 0
	26	#define DEBUGP printk
	27	#else
	28	#define DEBUGP(format, args...)
	29	#endif
	30
	31	/* Returns 1 if the spi is matched by the range, 0 otherwise */
	32	static inline int
	33	spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
	34	{
	35	int r=0;
	36	DEBUGP("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
	37	min,spi,max);
	38	r = (spi >= min && spi <= max) ^ invert;
	39	DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
	40	return r;
	41	}
	42
	43	static int
	44	match(const struct sk_buff *skb,
	45	const struct net_device *in,
	46	const struct net_device *out,
c4986734	47	const struct xt_match *match,
1da177e4 LT	48	const void *matchinfo,
	49	int offset,
	50	unsigned int protoff,
	51	int *hotdrop)
	52	{
e674d0f3	53	struct ip_auth_hdr *ah, _ah;
1da177e4	54	const struct ip6t_ah *ahinfo = matchinfo;
1da177e4 LT	55	unsigned int ptr;
1da177e4 LT	56	unsigned int hdrlen = 0;
6d381634	57	int err;
1da177e4	58
6d381634 PM	59	err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL);
	60	if (err < 0) {
	61	if (err != -ENOENT)
	62	*hotdrop = 1;
1da177e4	63	return 0;
6d381634	64	}
1da177e4	65
e674d0f3 YK	66	ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
e674d0f3 YK	67	if (ah == NULL) {
1da177e4 LT	68	*hotdrop = 1;
	69	return 0;
	70	}
	71
e674d0f3	72	hdrlen = (ah->hdrlen + 2) << 2;
1da177e4 LT	73
	74	DEBUGP("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
	75	DEBUGP("RES %04X ", ah->reserved);
	76	DEBUGP("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));
	77
	78	DEBUGP("IPv6 AH spi %02X ",
	79	(spi_match(ahinfo->spis[0], ahinfo->spis[1],
	80	ntohl(ah->spi),
	81	!!(ahinfo->invflags & IP6T_AH_INV_SPI))));
	82	DEBUGP("len %02X %04X %02X ",
	83	ahinfo->hdrlen, hdrlen,
	84	(!ahinfo->hdrlen \|\|
	85	(ahinfo->hdrlen == hdrlen) ^
	86	!!(ahinfo->invflags & IP6T_AH_INV_LEN)));
	87	DEBUGP("res %02X %04X %02X\n",
	88	ahinfo->hdrres, ah->reserved,
	89	!(ahinfo->hdrres && ah->reserved));
	90
	91	return (ah != NULL)
	92	&&
	93	(spi_match(ahinfo->spis[0], ahinfo->spis[1],
	94	ntohl(ah->spi),
	95	!!(ahinfo->invflags & IP6T_AH_INV_SPI)))
	96	&&
	97	(!ahinfo->hdrlen \|\|
	98	(ahinfo->hdrlen == hdrlen) ^
	99	!!(ahinfo->invflags & IP6T_AH_INV_LEN))
	100	&&
	101	!(ahinfo->hdrres && ah->reserved);
	102	}
	103
	104	/* Called when user tries to insert an entry of this type. */
	105	static int
	106	checkentry(const char *tablename,
2e4e6a17	107	const void *entry,
c4986734	108	const struct xt_match *match,
1da177e4	109	void *matchinfo,
1da177e4 LT	110	unsigned int hook_mask)
	111	{
	112	const struct ip6t_ah *ahinfo = matchinfo;
	113
1da177e4 LT	114	if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
	115	DEBUGP("ip6t_ah: unknown flags %X\n", ahinfo->invflags);
	116	return 0;
	117	}
	118	return 1;
	119	}
	120
	121	static struct ip6t_match ah_match = {
	122	.name = "ah",
7f939713 PM	123	.match = match,
	124	.matchsize = sizeof(struct ip6t_ah),
	125	.checkentry = checkentry,
1da177e4 LT	126	.me = THIS_MODULE,
	127	};
	128
65b4b4e8	129	static int __init ip6t_ah_init(void)
1da177e4 LT	130	{
	131	return ip6t_register_match(&ah_match);
	132	}
	133
65b4b4e8	134	static void __exit ip6t_ah_fini(void)
1da177e4 LT	135	{
	136	ip6t_unregister_match(&ah_match);
	137	}
	138
65b4b4e8 AM	139	module_init(ip6t_ah_init);
65b4b4e8 AM	140	module_exit(ip6t_ah_fini);