[mirror_ubuntu-bionic-kernel.git] / net / netfilter / xt_RATEEST.c

/*
 * (C) 2007 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.
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/gen_stats.h>
#include <linux/jhash.h>
#include <linux/rtnetlink.h>
#include <linux/random.h>
#include <net/gen_stats.h>
#include <net/netlink.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_RATEEST.h>
#include <net/netfilter/xt_rateest.h>

static DEFINE_MUTEX(xt_rateest_mutex);

#define RATEEST_HSIZE	16
static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly;
static unsigned int jhash_rnd __read_mostly;
static bool rnd_inited __read_mostly;

static unsigned int xt_rateest_hash(const char *name)
{
	return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) &
	       (RATEEST_HSIZE - 1);
}

static void xt_rateest_hash_insert(struct xt_rateest *est)
{
	unsigned int h;

	h = xt_rateest_hash(est->name);
	hlist_add_head(&est->list, &rateest_hash[h]);
}

struct xt_rateest *xt_rateest_lookup(const char *name)
{
	struct xt_rateest *est;
	struct hlist_node *n;
	unsigned int h;

	h = xt_rateest_hash(name);
	mutex_lock(&xt_rateest_mutex);
	hlist_for_each_entry(est, n, &rateest_hash[h], list) {
		if (strcmp(est->name, name) == 0) {
			est->refcnt++;
			mutex_unlock(&xt_rateest_mutex);
			return est;
		}
	}
	mutex_unlock(&xt_rateest_mutex);
	return NULL;
}
EXPORT_SYMBOL_GPL(xt_rateest_lookup);

void xt_rateest_put(struct xt_rateest *est)
{
	mutex_lock(&xt_rateest_mutex);
	if (--est->refcnt == 0) {
		hlist_del(&est->list);
		gen_kill_estimator(&est->bstats, &est->rstats);
		kfree(est);
	}
	mutex_unlock(&xt_rateest_mutex);
}
EXPORT_SYMBOL_GPL(xt_rateest_put);

static unsigned int
xt_rateest_tg(struct sk_buff *skb, const struct xt_target_param *par)
{
	const struct xt_rateest_target_info *info = par->targinfo;
	struct gnet_stats_basic_packed *stats = &info->est->bstats;

	spin_lock_bh(&info->est->lock);
	stats->bytes += skb->len;
	stats->packets++;
	spin_unlock_bh(&info->est->lock);

	return XT_CONTINUE;
}

static bool xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
{
	struct xt_rateest_target_info *info = par->targinfo;
	struct xt_rateest *est;
	struct {
		struct nlattr		opt;
		struct gnet_estimator	est;
	} cfg;

	if (unlikely(!rnd_inited)) {
		get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
		rnd_inited = true;
	}

	est = xt_rateest_lookup(info->name);
	if (est) {
		/*
		 * If estimator parameters are specified, they must match the
		 * existing estimator.
		 */
		if ((!info->interval && !info->ewma_log) ||
		    (info->interval != est->params.interval ||
		     info->ewma_log != est->params.ewma_log)) {
			xt_rateest_put(est);
			return false;
		}
		info->est = est;
		return true;
	}

	est = kzalloc(sizeof(*est), GFP_KERNEL);
	if (!est)
		goto err1;

	strlcpy(est->name, info->name, sizeof(est->name));
	spin_lock_init(&est->lock);
	est->refcnt		= 1;
	est->params.interval	= info->interval;
	est->params.ewma_log	= info->ewma_log;

	cfg.opt.nla_len		= nla_attr_size(sizeof(cfg.est));
	cfg.opt.nla_type	= TCA_STATS_RATE_EST;
	cfg.est.interval	= info->interval;
	cfg.est.ewma_log	= info->ewma_log;

	if (gen_new_estimator(&est->bstats, &est->rstats, &est->lock,
			      &cfg.opt) < 0)
		goto err2;

	info->est = est;
	xt_rateest_hash_insert(est);

	return true;

err2:
	kfree(est);
err1:
	return false;
}

static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
{
	struct xt_rateest_target_info *info = par->targinfo;

	xt_rateest_put(info->est);
}

static struct xt_target xt_rateest_tg_reg __read_mostly = {
	.name       = "RATEEST",
	.revision   = 0,
	.family     = NFPROTO_UNSPEC,
	.target     = xt_rateest_tg,
	.checkentry = xt_rateest_tg_checkentry,
	.destroy    = xt_rateest_tg_destroy,
	.targetsize = sizeof(struct xt_rateest_target_info),
	.me         = THIS_MODULE,
};

static int __init xt_rateest_tg_init(void)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
		INIT_HLIST_HEAD(&rateest_hash[i]);

	return xt_register_target(&xt_rateest_tg_reg);
}

static void __exit xt_rateest_tg_fini(void)
{
	xt_unregister_target(&xt_rateest_tg_reg);
}


MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Xtables: packet rate estimator");
MODULE_ALIAS("ipt_RATEEST");
MODULE_ALIAS("ip6t_RATEEST");
module_init(xt_rateest_tg_init);
module_exit(xt_rateest_tg_fini);
Commit	Line	Data
5859034d PM	1	/*
	2	* (C) 2007 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	#include <linux/module.h>
	9	#include <linux/skbuff.h>
	10	#include <linux/gen_stats.h>
	11	#include <linux/jhash.h>
	12	#include <linux/rtnetlink.h>
	13	#include <linux/random.h>
	14	#include <net/gen_stats.h>
1e90474c	15	#include <net/netlink.h>
5859034d PM	16
	17	#include <linux/netfilter/x_tables.h>
	18	#include <linux/netfilter/xt_RATEEST.h>
	19	#include <net/netfilter/xt_rateest.h>
	20
	21	static DEFINE_MUTEX(xt_rateest_mutex);
	22
	23	#define RATEEST_HSIZE 16
	24	static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly;
	25	static unsigned int jhash_rnd __read_mostly;
5191d501	26	static bool rnd_inited __read_mostly;
5859034d PM	27
	28	static unsigned int xt_rateest_hash(const char *name)
	29	{
	30	return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) &
	31	(RATEEST_HSIZE - 1);
	32	}
	33
	34	static void xt_rateest_hash_insert(struct xt_rateest *est)
	35	{
	36	unsigned int h;
	37
	38	h = xt_rateest_hash(est->name);
	39	hlist_add_head(&est->list, &rateest_hash[h]);
	40	}
	41
	42	struct xt_rateest xt_rateest_lookup(const char name)
	43	{
	44	struct xt_rateest *est;
	45	struct hlist_node *n;
	46	unsigned int h;
	47
	48	h = xt_rateest_hash(name);
	49	mutex_lock(&xt_rateest_mutex);
	50	hlist_for_each_entry(est, n, &rateest_hash[h], list) {
	51	if (strcmp(est->name, name) == 0) {
	52	est->refcnt++;
	53	mutex_unlock(&xt_rateest_mutex);
	54	return est;
	55	}
	56	}
	57	mutex_unlock(&xt_rateest_mutex);
	58	return NULL;
	59	}
	60	EXPORT_SYMBOL_GPL(xt_rateest_lookup);
	61
	62	void xt_rateest_put(struct xt_rateest *est)
	63	{
	64	mutex_lock(&xt_rateest_mutex);
	65	if (--est->refcnt == 0) {
	66	hlist_del(&est->list);
	67	gen_kill_estimator(&est->bstats, &est->rstats);
	68	kfree(est);
	69	}
	70	mutex_unlock(&xt_rateest_mutex);
	71	}
	72	EXPORT_SYMBOL_GPL(xt_rateest_put);
	73
	74	static unsigned int
7eb35586	75	xt_rateest_tg(struct sk_buff skb, const struct xt_target_param par)
5859034d	76	{
7eb35586	77	const struct xt_rateest_target_info *info = par->targinfo;
c1a8f1f1	78	struct gnet_stats_basic_packed *stats = &info->est->bstats;
5859034d PM	79
	80	spin_lock_bh(&info->est->lock);
	81	stats->bytes += skb->len;
	82	stats->packets++;
	83	spin_unlock_bh(&info->est->lock);
	84
	85	return XT_CONTINUE;
	86	}
	87
af5d6dc2	88	static bool xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
5859034d	89	{
af5d6dc2	90	struct xt_rateest_target_info *info = par->targinfo;
5859034d PM	91	struct xt_rateest *est;
5859034d PM	92	struct {
1e90474c	93	struct nlattr opt;
5859034d PM	94	struct gnet_estimator est;
	95	} cfg;
	96
5191d501 JE	97	if (unlikely(!rnd_inited)) {
	98	get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
	99	rnd_inited = true;
	100	}
	101
5859034d PM	102	est = xt_rateest_lookup(info->name);
	103	if (est) {
	104	/*
	105	* If estimator parameters are specified, they must match the
	106	* existing estimator.
	107	*/
	108	if ((!info->interval && !info->ewma_log) \|\|
	109	(info->interval != est->params.interval \|\|
	110	info->ewma_log != est->params.ewma_log)) {
	111	xt_rateest_put(est);
	112	return false;
	113	}
	114	info->est = est;
	115	return true;
	116	}
	117
	118	est = kzalloc(sizeof(*est), GFP_KERNEL);
	119	if (!est)
	120	goto err1;
	121
	122	strlcpy(est->name, info->name, sizeof(est->name));
	123	spin_lock_init(&est->lock);
	124	est->refcnt = 1;
	125	est->params.interval = info->interval;
	126	est->params.ewma_log = info->ewma_log;
	127
1e90474c PM	128	cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est));
1e90474c PM	129	cfg.opt.nla_type = TCA_STATS_RATE_EST;
5859034d PM	130	cfg.est.interval = info->interval;
	131	cfg.est.ewma_log = info->ewma_log;
	132
	133	if (gen_new_estimator(&est->bstats, &est->rstats, &est->lock,
	134	&cfg.opt) < 0)
	135	goto err2;
	136
	137	info->est = est;
	138	xt_rateest_hash_insert(est);
	139
	140	return true;
	141
	142	err2:
	143	kfree(est);
	144	err1:
	145	return false;
	146	}
	147
a2df1648	148	static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
5859034d	149	{
a2df1648	150	struct xt_rateest_target_info *info = par->targinfo;
5859034d PM	151
	152	xt_rateest_put(info->est);
	153	}
	154
55b69e91 JE	155	static struct xt_target xt_rateest_tg_reg __read_mostly = {
	156	.name = "RATEEST",
	157	.revision = 0,
	158	.family = NFPROTO_UNSPEC,
	159	.target = xt_rateest_tg,
	160	.checkentry = xt_rateest_tg_checkentry,
	161	.destroy = xt_rateest_tg_destroy,
	162	.targetsize = sizeof(struct xt_rateest_target_info),
	163	.me = THIS_MODULE,
5859034d PM	164	};
	165
	166	static int __init xt_rateest_tg_init(void)
	167	{
	168	unsigned int i;
	169
	170	for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
	171	INIT_HLIST_HEAD(&rateest_hash[i]);
	172
55b69e91	173	return xt_register_target(&xt_rateest_tg_reg);
5859034d PM	174	}
	175
	176	static void __exit xt_rateest_tg_fini(void)
	177	{
55b69e91	178	xt_unregister_target(&xt_rateest_tg_reg);
5859034d PM	179	}
	180
	181
	182	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
	183	MODULE_LICENSE("GPL");
2ae15b64	184	MODULE_DESCRIPTION("Xtables: packet rate estimator");
5859034d PM	185	MODULE_ALIAS("ipt_RATEEST");
	186	MODULE_ALIAS("ip6t_RATEEST");
	187	module_init(xt_rateest_tg_init);
	188	module_exit(xt_rateest_tg_fini);