[linux-2.6-block.git] / net / netfilter / xt_length.c

/* Kernel module to match packet length. */
/* (C) 1999-2001 James Morris <jmorros@intercode.com.au>
 *
 * 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 <net/ip.h>

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

MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
MODULE_DESCRIPTION("Xtables: Packet length (Layer3,4,5) match");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_length");
MODULE_ALIAS("ip6t_length");

static bool
length_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_length_info *info = par->matchinfo;
	u_int16_t pktlen = ntohs(ip_hdr(skb)->tot_len);

	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
}

static bool
length_mt6(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_length_info *info = par->matchinfo;
	const u_int16_t pktlen = ntohs(ipv6_hdr(skb)->payload_len) +
				 sizeof(struct ipv6hdr);

	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
}

static struct xt_match length_mt_reg[] __read_mostly = {
	{
		.name		= "length",
		.family		= NFPROTO_IPV4,
		.match		= length_mt,
		.matchsize	= sizeof(struct xt_length_info),
		.me		= THIS_MODULE,
	},
	{
		.name		= "length",
		.family		= NFPROTO_IPV6,
		.match		= length_mt6,
		.matchsize	= sizeof(struct xt_length_info),
		.me		= THIS_MODULE,
	},
};

static int __init length_mt_init(void)
{
	return xt_register_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg));
}

static void __exit length_mt_exit(void)
{
	xt_unregister_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg));
}

module_init(length_mt_init);
module_exit(length_mt_exit);
Commit	Line	Data
	1	/* Kernel module to match packet length. */
	2	/* (C) 1999-2001 James Morris <jmorros@intercode.com.au>
	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
	9	#include <linux/module.h>
	10	#include <linux/skbuff.h>
	11	#include <linux/ipv6.h>
	12	#include <net/ip.h>
	13
	14	#include <linux/netfilter/xt_length.h>
	15	#include <linux/netfilter/x_tables.h>
	16
	17	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
	18	MODULE_DESCRIPTION("Xtables: Packet length (Layer3,4,5) match");
	19	MODULE_LICENSE("GPL");
	20	MODULE_ALIAS("ipt_length");
	21	MODULE_ALIAS("ip6t_length");
	22
	23	static bool
	24	length_mt(const struct sk_buff skb, struct xt_action_param par)
	25	{
	26	const struct xt_length_info *info = par->matchinfo;
	27	u_int16_t pktlen = ntohs(ip_hdr(skb)->tot_len);
	28
	29	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
	30	}
	31
	32	static bool
	33	length_mt6(const struct sk_buff skb, struct xt_action_param par)
	34	{
	35	const struct xt_length_info *info = par->matchinfo;
	36	const u_int16_t pktlen = ntohs(ipv6_hdr(skb)->payload_len) +
	37	sizeof(struct ipv6hdr);
	38
	39	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
	40	}
	41
	42	static struct xt_match length_mt_reg[] __read_mostly = {
	43	{
	44	.name = "length",
	45	.family = NFPROTO_IPV4,
	46	.match = length_mt,
	47	.matchsize = sizeof(struct xt_length_info),
	48	.me = THIS_MODULE,
	49	},
	50	{
	51	.name = "length",
	52	.family = NFPROTO_IPV6,
	53	.match = length_mt6,
	54	.matchsize = sizeof(struct xt_length_info),
	55	.me = THIS_MODULE,
	56	},
	57	};
	58
	59	static int __init length_mt_init(void)
	60	{
	61	return xt_register_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg));
	62	}
	63
	64	static void __exit length_mt_exit(void)
	65	{
	66	xt_unregister_matches(length_mt_reg, ARRAY_SIZE(length_mt_reg));
	67	}
	68
	69	module_init(length_mt_init);
	70	module_exit(length_mt_exit);