[net-next-2.6.git] / net / ipv4 / netfilter / ipt_ah.c

/* Kernel module to match AH parameters. */
/* (C) 1999-2000 Yon Uriarte <yon@astaro.de>
 *
 * 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/in.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>

#include <linux/netfilter_ipv4/ipt_ah.h>
#include <linux/netfilter/x_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
MODULE_DESCRIPTION("Xtables: IPv4 IPsec-AH SPI match");

#ifdef DEBUG_CONNTRACK
#define duprintf(format, args...) printk(format , ## args)
#else
#define duprintf(format, args...)
#endif

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

static bool ah_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
	struct ip_auth_hdr _ahdr;
	const struct ip_auth_hdr *ah;
	const struct ipt_ah *ahinfo = par->matchinfo;

	/* Must not be a fragment. */
	if (par->fragoff != 0)
		return false;

	ah = skb_header_pointer(skb, par->thoff, sizeof(_ahdr), &_ahdr);
	if (ah == NULL) {
		/* We've been asked to examine this packet, and we
		 * can't.  Hence, no choice but to drop.
		 */
		duprintf("Dropping evil AH tinygram.\n");
		*par->hotdrop = true;
		return 0;
	}

	return spi_match(ahinfo->spis[0], ahinfo->spis[1],
			 ntohl(ah->spi),
			 !!(ahinfo->invflags & IPT_AH_INV_SPI));
}

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

	/* Must specify no unknown invflags */
	if (ahinfo->invflags & ~IPT_AH_INV_MASK) {
		duprintf("ipt_ah: unknown flags %X\n", ahinfo->invflags);
		return false;
	}
	return true;
}

static struct xt_match ah_mt_reg __read_mostly = {
	.name		= "ah",
	.family		= NFPROTO_IPV4,
	.match		= ah_mt,
	.matchsize	= sizeof(struct ipt_ah),
	.proto		= IPPROTO_AH,
	.checkentry	= ah_mt_check,
	.me		= THIS_MODULE,
};

static int __init ah_mt_init(void)
{
	return xt_register_match(&ah_mt_reg);
}

static void __exit ah_mt_exit(void)
{
	xt_unregister_match(&ah_mt_reg);
}

module_init(ah_mt_init);
module_exit(ah_mt_exit);
Commit	Line	Data
1da177e4 LT	1	/* Kernel module to match AH parameters. */
	2	/* (C) 1999-2000 Yon Uriarte <yon@astaro.de>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*/
	8
6709dbbb	9	#include <linux/in.h>
1da177e4 LT	10	#include <linux/module.h>
	11	#include <linux/skbuff.h>
	12	#include <linux/ip.h>
	13
	14	#include <linux/netfilter_ipv4/ipt_ah.h>
6709dbbb	15	#include <linux/netfilter/x_tables.h>
1da177e4 LT	16
	17	MODULE_LICENSE("GPL");
	18	MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
2ae15b64	19	MODULE_DESCRIPTION("Xtables: IPv4 IPsec-AH SPI match");
1da177e4 LT	20
	21	#ifdef DEBUG_CONNTRACK
	22	#define duprintf(format, args...) printk(format , ## args)
	23	#else
	24	#define duprintf(format, args...)
	25	#endif
	26
	27	/* Returns 1 if the spi is matched by the range, 0 otherwise */
1d93a9cb JE	28	static inline bool
1d93a9cb JE	29	spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
1da177e4	30	{
1d93a9cb	31	bool r;
e905a9ed YH	32	duprintf("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
e905a9ed YH	33	min,spi,max);
1da177e4 LT	34	r=(spi >= min && spi <= max) ^ invert;
	35	duprintf(" result %s\n",r? "PASS" : "FAILED");
	36	return r;
	37	}
	38
f7108a20	39	static bool ah_mt(const struct sk_buff skb, const struct xt_match_param par)
1da177e4	40	{
a47362a2 JE	41	struct ip_auth_hdr _ahdr;
a47362a2 JE	42	const struct ip_auth_hdr *ah;
f7108a20	43	const struct ipt_ah *ahinfo = par->matchinfo;
1da177e4 LT	44
1da177e4 LT	45	/* Must not be a fragment. */
f7108a20	46	if (par->fragoff != 0)
1d93a9cb	47	return false;
1da177e4	48
f7108a20	49	ah = skb_header_pointer(skb, par->thoff, sizeof(_ahdr), &_ahdr);
1da177e4 LT	50	if (ah == NULL) {
	51	/* We've been asked to examine this packet, and we
	52	* can't. Hence, no choice but to drop.
	53	*/
	54	duprintf("Dropping evil AH tinygram.\n");
f7108a20	55	*par->hotdrop = true;
1da177e4 LT	56	return 0;
	57	}
	58
	59	return spi_match(ahinfo->spis[0], ahinfo->spis[1],
	60	ntohl(ah->spi),
	61	!!(ahinfo->invflags & IPT_AH_INV_SPI));
	62	}
	63
	64	/* Called when user tries to insert an entry of this type. */
ccb79bdc	65	static bool
d3c5ee6d JE	66	ah_mt_check(const char tablename, const void ip_void,
	67	const struct xt_match match, void matchinfo,
	68	unsigned int hook_mask)
1da177e4 LT	69	{
	70	const struct ipt_ah *ahinfo = matchinfo;
	71
1d5cd909	72	/* Must specify no unknown invflags */
1da177e4	73	if (ahinfo->invflags & ~IPT_AH_INV_MASK) {
1d5cd909	74	duprintf("ipt_ah: unknown flags %X\n", ahinfo->invflags);
ccb79bdc	75	return false;
1da177e4	76	}
ccb79bdc	77	return true;
1da177e4 LT	78	}
1da177e4 LT	79
d3c5ee6d	80	static struct xt_match ah_mt_reg __read_mostly = {
1da177e4	81	.name = "ah",
ee999d8b	82	.family = NFPROTO_IPV4,
d3c5ee6d	83	.match = ah_mt,
1d5cd909 PM	84	.matchsize = sizeof(struct ipt_ah),
1d5cd909 PM	85	.proto = IPPROTO_AH,
d3c5ee6d	86	.checkentry = ah_mt_check,
1da177e4 LT	87	.me = THIS_MODULE,
	88	};
	89
d3c5ee6d	90	static int __init ah_mt_init(void)
1da177e4	91	{
d3c5ee6d	92	return xt_register_match(&ah_mt_reg);
1da177e4 LT	93	}
1da177e4 LT	94
d3c5ee6d	95	static void __exit ah_mt_exit(void)
1da177e4	96	{
d3c5ee6d	97	xt_unregister_match(&ah_mt_reg);
1da177e4 LT	98	}
1da177e4 LT	99
d3c5ee6d JE	100	module_init(ah_mt_init);
d3c5ee6d JE	101	module_exit(ah_mt_exit);