[deliverable/linux.git] / net / netfilter / xt_esp.c

/* Kernel module to match ESP 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/module.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/ip.h>

#include <linux/netfilter/xt_esp.h>
#include <linux/netfilter/x_tables.h>

#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
MODULE_DESCRIPTION("Xtables: IPsec-ESP packet match");
MODULE_ALIAS("ipt_esp");
MODULE_ALIAS("ip6t_esp");

#if 0
#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("esp 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
esp_mt(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)
{
	const struct ip_esp_hdr *eh;
	struct ip_esp_hdr _esp;
	const struct xt_esp *espinfo = matchinfo;

	/* Must not be a fragment. */
	if (offset)
		return false;

	eh = skb_header_pointer(skb, protoff, sizeof(_esp), &_esp);
	if (eh == NULL) {
		/* We've been asked to examine this packet, and we
		 * can't.  Hence, no choice but to drop.
		 */
		duprintf("Dropping evil ESP tinygram.\n");
		*hotdrop = true;
		return false;
	}

	return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi),
			 !!(espinfo->invflags & XT_ESP_INV_SPI));
}

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

	if (espinfo->invflags & ~XT_ESP_INV_MASK) {
		duprintf("xt_esp: unknown flags %X\n", espinfo->invflags);
		return false;
	}

	return true;
}

static struct xt_match esp_mt_reg[] __read_mostly = {
	{
		.name		= "esp",
		.family		= AF_INET,
		.checkentry	= esp_mt_check,
		.match		= esp_mt,
		.matchsize	= sizeof(struct xt_esp),
		.proto		= IPPROTO_ESP,
		.me		= THIS_MODULE,
	},
	{
		.name		= "esp",
		.family		= AF_INET6,
		.checkentry	= esp_mt_check,
		.match		= esp_mt,
		.matchsize	= sizeof(struct xt_esp),
		.proto		= IPPROTO_ESP,
		.me		= THIS_MODULE,
	},
};

static int __init esp_mt_init(void)
{
	return xt_register_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg));
}

static void __exit esp_mt_exit(void)
{
	xt_unregister_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg));
}

module_init(esp_mt_init);
module_exit(esp_mt_exit);
Commit	Line	Data
1da177e4 LT	1	/* Kernel module to match ESP parameters. */
	2
	3	/* (C) 1999-2000 Yon Uriarte <yon@astaro.de>
	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>
dc5ab2fa	12	#include <linux/in.h>
1da177e4 LT	13	#include <linux/ip.h>
1da177e4 LT	14
dc5ab2fa YK	15	#include <linux/netfilter/xt_esp.h>
	16	#include <linux/netfilter/x_tables.h>
	17
1da177e4	18	#include <linux/netfilter_ipv4/ip_tables.h>
dc5ab2fa	19	#include <linux/netfilter_ipv6/ip6_tables.h>
1da177e4 LT	20
	21	MODULE_LICENSE("GPL");
	22	MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
2ae15b64	23	MODULE_DESCRIPTION("Xtables: IPsec-ESP packet match");
dc5ab2fa YK	24	MODULE_ALIAS("ipt_esp");
dc5ab2fa YK	25	MODULE_ALIAS("ip6t_esp");
1da177e4	26
dc5ab2fa	27	#if 0
1da177e4 LT	28	#define duprintf(format, args...) printk(format , ## args)
	29	#else
	30	#define duprintf(format, args...)
	31	#endif
	32
	33	/* Returns 1 if the spi is matched by the range, 0 otherwise */
1d93a9cb JE	34	static inline bool
1d93a9cb JE	35	spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
1da177e4	36	{
1d93a9cb	37	bool r;
dc5ab2fa YK	38	duprintf("esp spi_match:%c 0x%x <= 0x%x <= 0x%x", invert ? '!' : ' ',
	39	min, spi, max);
	40	r = (spi >= min && spi <= max) ^ invert;
	41	duprintf(" result %s\n", r ? "PASS" : "FAILED");
1da177e4 LT	42	return r;
	43	}
	44
1d93a9cb	45	static bool
d3c5ee6d JE	46	esp_mt(const struct sk_buff skb, const struct net_device in,
	47	const struct net_device out, const struct xt_match match,
	48	const void matchinfo, int offset, unsigned int protoff, bool hotdrop)
1da177e4	49	{
3cf93c96 JE	50	const struct ip_esp_hdr *eh;
3cf93c96 JE	51	struct ip_esp_hdr _esp;
dc5ab2fa	52	const struct xt_esp *espinfo = matchinfo;
1da177e4 LT	53
	54	/* Must not be a fragment. */
	55	if (offset)
1d93a9cb	56	return false;
1da177e4	57
dc5ab2fa	58	eh = skb_header_pointer(skb, protoff, sizeof(_esp), &_esp);
1da177e4 LT	59	if (eh == NULL) {
	60	/* We've been asked to examine this packet, and we
	61	* can't. Hence, no choice but to drop.
	62	*/
	63	duprintf("Dropping evil ESP tinygram.\n");
cff533ac	64	*hotdrop = true;
1d93a9cb	65	return false;
1da177e4 LT	66	}
1da177e4 LT	67
dc5ab2fa YK	68	return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi),
dc5ab2fa YK	69	!!(espinfo->invflags & XT_ESP_INV_SPI));
1da177e4 LT	70	}
	71
	72	/* Called when user tries to insert an entry of this type. */
ccb79bdc	73	static bool
d3c5ee6d JE	74	esp_mt_check(const char tablename, const void ip_void,
	75	const struct xt_match match, void matchinfo,
	76	unsigned int hook_mask)
1da177e4	77	{
dc5ab2fa	78	const struct xt_esp *espinfo = matchinfo;
1da177e4	79
dc5ab2fa YK	80	if (espinfo->invflags & ~XT_ESP_INV_MASK) {
dc5ab2fa YK	81	duprintf("xt_esp: unknown flags %X\n", espinfo->invflags);
ccb79bdc	82	return false;
1da177e4	83	}
dc5ab2fa	84
ccb79bdc	85	return true;
1da177e4 LT	86	}
1da177e4 LT	87
d3c5ee6d	88	static struct xt_match esp_mt_reg[] __read_mostly = {
4470bbc7 PM	89	{
	90	.name = "esp",
	91	.family = AF_INET,
d3c5ee6d JE	92	.checkentry = esp_mt_check,
d3c5ee6d JE	93	.match = esp_mt,
4470bbc7 PM	94	.matchsize = sizeof(struct xt_esp),
	95	.proto = IPPROTO_ESP,
	96	.me = THIS_MODULE,
	97	},
	98	{
	99	.name = "esp",
	100	.family = AF_INET6,
d3c5ee6d JE	101	.checkentry = esp_mt_check,
d3c5ee6d JE	102	.match = esp_mt,
4470bbc7 PM	103	.matchsize = sizeof(struct xt_esp),
	104	.proto = IPPROTO_ESP,
	105	.me = THIS_MODULE,
	106	},
dc5ab2fa YK	107	};
dc5ab2fa YK	108
d3c5ee6d	109	static int __init esp_mt_init(void)
1da177e4	110	{
d3c5ee6d	111	return xt_register_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg));
1da177e4 LT	112	}
1da177e4 LT	113
d3c5ee6d	114	static void __exit esp_mt_exit(void)
1da177e4	115	{
d3c5ee6d	116	xt_unregister_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg));
1da177e4 LT	117	}
1da177e4 LT	118
d3c5ee6d JE	119	module_init(esp_mt_init);
d3c5ee6d JE	120	module_exit(esp_mt_exit);