[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / netfilter / xt_statistic.c

/*
 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
 *
 * 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.
 *
 * Based on ipt_random and ipt_nth by Fabrice MARIE <fabrice@netfilter.org>.
 */

#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#include <linux/net.h>
#include <linux/slab.h>

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

struct xt_statistic_priv {
	uint32_t count;
};

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)");
MODULE_ALIAS("ipt_statistic");
MODULE_ALIAS("ip6t_statistic");

static DEFINE_SPINLOCK(nth_lock);

static bool
statistic_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_statistic_info *info = par->matchinfo;
	bool ret = info->flags & XT_STATISTIC_INVERT;

	switch (info->mode) {
	case XT_STATISTIC_MODE_RANDOM:
		if ((net_random() & 0x7FFFFFFF) < info->u.random.probability)
			ret = !ret;
		break;
	case XT_STATISTIC_MODE_NTH:
		spin_lock_bh(&nth_lock);
		if (info->master->count++ == info->u.nth.every) {
			info->master->count = 0;
			ret = !ret;
		}
		spin_unlock_bh(&nth_lock);
		break;
	}

	return ret;
}

static int statistic_mt_check(const struct xt_mtchk_param *par)
{
	struct xt_statistic_info *info = par->matchinfo;

	if (info->mode > XT_STATISTIC_MODE_MAX ||
	    info->flags & ~XT_STATISTIC_MASK)
		return -EINVAL;

	info->master = kzalloc(sizeof(*info->master), GFP_KERNEL);
	if (info->master == NULL)
		return -ENOMEM;
	info->master->count = info->u.nth.count;

	return 0;
}

static void statistic_mt_destroy(const struct xt_mtdtor_param *par)
{
	const struct xt_statistic_info *info = par->matchinfo;

	kfree(info->master);
}

static struct xt_match xt_statistic_mt_reg __read_mostly = {
	.name       = "statistic",
	.revision   = 0,
	.family     = NFPROTO_UNSPEC,
	.match      = statistic_mt,
	.checkentry = statistic_mt_check,
	.destroy    = statistic_mt_destroy,
	.matchsize  = sizeof(struct xt_statistic_info),
	.me         = THIS_MODULE,
};

static int __init statistic_mt_init(void)
{
	return xt_register_match(&xt_statistic_mt_reg);
}

static void __exit statistic_mt_exit(void)
{
	xt_unregister_match(&xt_statistic_mt_reg);
}

module_init(statistic_mt_init);
module_exit(statistic_mt_exit);
Commit	Line	Data
f3389805 PM	1	/*
	2	* Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
	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	* Based on ipt_random and ipt_nth by Fabrice MARIE <fabrice@netfilter.org>.
	9	*/
	10
	11	#include <linux/init.h>
	12	#include <linux/spinlock.h>
	13	#include <linux/skbuff.h>
	14	#include <linux/net.h>
5a0e3ad6	15	#include <linux/slab.h>
f3389805 PM	16
	17	#include <linux/netfilter/xt_statistic.h>
	18	#include <linux/netfilter/x_tables.h>
	19
acc738fe JE	20	struct xt_statistic_priv {
	21	uint32_t count;
	22	};
	23
f3389805 PM	24	MODULE_LICENSE("GPL");
f3389805 PM	25	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
2ae15b64	26	MODULE_DESCRIPTION("Xtables: statistics-based matching (\"Nth\", random)");
f3389805 PM	27	MODULE_ALIAS("ipt_statistic");
	28	MODULE_ALIAS("ip6t_statistic");
	29
	30	static DEFINE_SPINLOCK(nth_lock);
	31
1d93a9cb	32	static bool
62fc8051	33	statistic_mt(const struct sk_buff skb, struct xt_action_param par)
f3389805	34	{
acc738fe	35	const struct xt_statistic_info *info = par->matchinfo;
1d93a9cb	36	bool ret = info->flags & XT_STATISTIC_INVERT;
f3389805 PM	37
	38	switch (info->mode) {
	39	case XT_STATISTIC_MODE_RANDOM:
	40	if ((net_random() & 0x7FFFFFFF) < info->u.random.probability)
1d93a9cb	41	ret = !ret;
f3389805 PM	42	break;
f3389805 PM	43	case XT_STATISTIC_MODE_NTH:
f3389805	44	spin_lock_bh(&nth_lock);
acc738fe JE	45	if (info->master->count++ == info->u.nth.every) {
acc738fe JE	46	info->master->count = 0;
1d93a9cb	47	ret = !ret;
f3389805 PM	48	}
	49	spin_unlock_bh(&nth_lock);
	50	break;
	51	}
	52
	53	return ret;
	54	}
	55
b0f38452	56	static int statistic_mt_check(const struct xt_mtchk_param *par)
f3389805	57	{
9b4fce7a	58	struct xt_statistic_info *info = par->matchinfo;
f3389805 PM	59
	60	if (info->mode > XT_STATISTIC_MODE_MAX \|\|
	61	info->flags & ~XT_STATISTIC_MASK)
bd414ee6	62	return -EINVAL;
acc738fe JE	63
acc738fe JE	64	info->master = kzalloc(sizeof(*info->master), GFP_KERNEL);
85bc3f38	65	if (info->master == NULL)
4a5a5c73	66	return -ENOMEM;
acc738fe JE	67	info->master->count = info->u.nth.count;
acc738fe JE	68
bd414ee6	69	return 0;
f3389805 PM	70	}
f3389805 PM	71
acc738fe JE	72	static void statistic_mt_destroy(const struct xt_mtdtor_param *par)
	73	{
	74	const struct xt_statistic_info *info = par->matchinfo;
	75
	76	kfree(info->master);
	77	}
	78
55b69e91 JE	79	static struct xt_match xt_statistic_mt_reg __read_mostly = {
	80	.name = "statistic",
	81	.revision = 0,
	82	.family = NFPROTO_UNSPEC,
	83	.match = statistic_mt,
	84	.checkentry = statistic_mt_check,
acc738fe	85	.destroy = statistic_mt_destroy,
55b69e91 JE	86	.matchsize = sizeof(struct xt_statistic_info),
55b69e91 JE	87	.me = THIS_MODULE,
f3389805 PM	88	};
f3389805 PM	89
d3c5ee6d	90	static int __init statistic_mt_init(void)
f3389805	91	{
55b69e91	92	return xt_register_match(&xt_statistic_mt_reg);
f3389805 PM	93	}
f3389805 PM	94
d3c5ee6d	95	static void __exit statistic_mt_exit(void)
f3389805	96	{
55b69e91	97	xt_unregister_match(&xt_statistic_mt_reg);
f3389805 PM	98	}
f3389805 PM	99
d3c5ee6d JE	100	module_init(statistic_mt_init);
d3c5ee6d JE	101	module_exit(statistic_mt_exit);