/* * (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 <linux/slab.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	16static 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);		/*		 * gen_estimator est_timer() might access est->lock or bstats,		 * wait a RCU grace period before freeing 'est'		 */		kfree_rcu(est, rcu);	}	mutex_unlock(&xt_rateest_mutex);}EXPORT_SYMBOL_GPL(xt_rateest_put); static unsigned intxt_rateest_tg(struct sk_buff *skb, const struct xt_action_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 int 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;	int ret; 	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 -EINVAL;		}		info->est = est;		return 0;	} 	ret = -ENOMEM;	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; 	ret = gen_new_estimator(&est->bstats, &est->rstats,				&est->lock, &cfg.opt);	if (ret < 0)		goto err2; 	info->est = est;	xt_rateest_hash_insert(est);	return 0; err2:	kfree(est);err1:	return ret;} 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);