[deliverable/linux.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("IP tables packet length matching module");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_length");
MODULE_ALIAS("ip6t_length");

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)
{
	const struct xt_length_info *info = matchinfo;
	u_int16_t pktlen = ntohs(skb->nh.iph->tot_len);
	
	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
}

static int
match6(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)
{
	const struct xt_length_info *info = matchinfo;
	u_int16_t pktlen = ntohs(skb->nh.ipv6h->payload_len) + sizeof(struct ipv6hdr);
	
	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
}

static struct xt_match length_match = {
	.name		= "length",
	.match		= match,
	.matchsize	= sizeof(struct xt_length_info),
	.family		= AF_INET,
	.me		= THIS_MODULE,
};

static struct xt_match length6_match = {
	.name		= "length",
	.match		= match6,
	.matchsize	= sizeof(struct xt_length_info),
	.family		= AF_INET6,
	.me		= THIS_MODULE,
};

static int __init xt_length_init(void)
{
	int ret;
	ret = xt_register_match(&length_match);
	if (ret)
		return ret;
	ret = xt_register_match(&length6_match);
	if (ret)
		xt_unregister_match(&length_match);

	return ret;
}

static void __exit xt_length_fini(void)
{
	xt_unregister_match(&length_match);
	xt_unregister_match(&length6_match);
}

module_init(xt_length_init);
module_exit(xt_length_fini);
Commit	Line	Data
2e4e6a17 HW	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>
37d8dc82	11	#include <linux/ipv6.h>
2e4e6a17 HW	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("IP tables packet length matching module");
	19	MODULE_LICENSE("GPL");
	20	MODULE_ALIAS("ipt_length");
	21	MODULE_ALIAS("ip6t_length");
	22
	23	static int
	24	match(const struct sk_buff *skb,
	25	const struct net_device *in,
	26	const struct net_device *out,
c4986734	27	const struct xt_match *match,
2e4e6a17 HW	28	const void *matchinfo,
	29	int offset,
	30	unsigned int protoff,
	31	int *hotdrop)
	32	{
	33	const struct xt_length_info *info = matchinfo;
	34	u_int16_t pktlen = ntohs(skb->nh.iph->tot_len);
	35
	36	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
	37	}
	38
	39	static int
	40	match6(const struct sk_buff *skb,
	41	const struct net_device *in,
	42	const struct net_device *out,
c4986734	43	const struct xt_match *match,
2e4e6a17 HW	44	const void *matchinfo,
	45	int offset,
	46	unsigned int protoff,
	47	int *hotdrop)
	48	{
	49	const struct xt_length_info *info = matchinfo;
	50	u_int16_t pktlen = ntohs(skb->nh.ipv6h->payload_len) + sizeof(struct ipv6hdr);
	51
	52	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
	53	}
	54
2e4e6a17 HW	55	static struct xt_match length_match = {
2e4e6a17 HW	56	.name = "length",
5d04bff0 PM	57	.match = match,
5d04bff0 PM	58	.matchsize = sizeof(struct xt_length_info),
a45049c5	59	.family = AF_INET,
2e4e6a17 HW	60	.me = THIS_MODULE,
2e4e6a17 HW	61	};
5d04bff0	62
2e4e6a17 HW	63	static struct xt_match length6_match = {
2e4e6a17 HW	64	.name = "length",
5d04bff0 PM	65	.match = match6,
5d04bff0 PM	66	.matchsize = sizeof(struct xt_length_info),
a45049c5	67	.family = AF_INET6,
2e4e6a17 HW	68	.me = THIS_MODULE,
	69	};
	70
65b4b4e8	71	static int __init xt_length_init(void)
2e4e6a17 HW	72	{
2e4e6a17 HW	73	int ret;
a45049c5	74	ret = xt_register_match(&length_match);
2e4e6a17 HW	75	if (ret)
2e4e6a17 HW	76	return ret;
a45049c5	77	ret = xt_register_match(&length6_match);
2e4e6a17	78	if (ret)
a45049c5	79	xt_unregister_match(&length_match);
2e4e6a17 HW	80
	81	return ret;
	82	}
	83
65b4b4e8	84	static void __exit xt_length_fini(void)
2e4e6a17	85	{
a45049c5 PNA	86	xt_unregister_match(&length_match);
a45049c5 PNA	87	xt_unregister_match(&length6_match);
2e4e6a17 HW	88	}
2e4e6a17 HW	89
65b4b4e8 AM	90	module_init(xt_length_init);
65b4b4e8 AM	91	module_exit(xt_length_fini);