// SPDX-License-Identifier: GPL-2.0-only/* * (C) 2007 Patrick McHardy <kaber@trash.net> */#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 <net/netns/generic.h> #include <linux/netfilter/x_tables.h>#include <linux/netfilter/xt_RATEEST.h>#include <net/netfilter/xt_rateest.h> #define RATEEST_HSIZE	16 struct xt_rateest_net {	struct mutex hash_lock;	struct hlist_head hash[RATEEST_HSIZE];}; static unsigned int xt_rateest_id; static unsigned int jhash_rnd __read_mostly; static unsigned int xt_rateest_hash(const char *name){	return jhash(name, sizeof_field(struct xt_rateest, name), jhash_rnd) &	       (RATEEST_HSIZE - 1);} static void xt_rateest_hash_insert(struct xt_rateest_net *xn,				   struct xt_rateest *est){	unsigned int h; 	h = xt_rateest_hash(est->name);	hlist_add_head(&est->list, &xn->hash[h]);} static struct xt_rateest *__xt_rateest_lookup(struct xt_rateest_net *xn,					      const char *name){	struct xt_rateest *est;	unsigned int h; 	h = xt_rateest_hash(name);	hlist_for_each_entry(est, &xn->hash[h], list) {		if (strcmp(est->name, name) == 0) {			est->refcnt++;			return est;		}	} 	return NULL;} struct xt_rateest *xt_rateest_lookup(struct net *net, const char *name){	struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);	struct xt_rateest *est; 	mutex_lock(&xn->hash_lock);	est = __xt_rateest_lookup(xn, name);	mutex_unlock(&xn->hash_lock);	return est;}EXPORT_SYMBOL_GPL(xt_rateest_lookup); void xt_rateest_put(struct net *net, struct xt_rateest *est){	struct xt_rateest_net *xn = net_generic(net, xt_rateest_id); 	mutex_lock(&xn->hash_lock);	if (--est->refcnt == 0) {		hlist_del(&est->list);		gen_kill_estimator(&est->rate_est);		/*		 * gen_estimator est_timer() might access est->lock or bstats,		 * wait a RCU grace period before freeing 'est'		 */		kfree_rcu(est, rcu);	}	mutex_unlock(&xn->hash_lock);}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_sync *stats = &info->est->bstats; 	spin_lock_bh(&info->est->lock);	u64_stats_add(&stats->bytes, skb->len);	u64_stats_inc(&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_net *xn = net_generic(par->net, xt_rateest_id);	struct xt_rateest_target_info *info = par->targinfo;	struct xt_rateest *est;	struct {		struct nlattr		opt;		struct gnet_estimator	est;	} cfg;	int ret; 	if (strnlen(info->name, sizeof(est->name)) >= sizeof(est->name))		return -ENAMETOOLONG; 	net_get_random_once(&jhash_rnd, sizeof(jhash_rnd)); 	mutex_lock(&xn->hash_lock);	est = __xt_rateest_lookup(xn, info->name);	if (est) {		mutex_unlock(&xn->hash_lock);		/*		 * 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(par->net, est);			return -EINVAL;		}		info->est = est;		return 0;	} 	ret = -ENOMEM;	est = kzalloc_obj(*est);	if (!est)		goto err1; 	gnet_stats_basic_sync_init(&est->bstats);	strscpy(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, NULL, &est->rate_est,				&est->lock, NULL, &cfg.opt);	if (ret < 0)		goto err2; 	info->est = est;	xt_rateest_hash_insert(xn, est);	mutex_unlock(&xn->hash_lock);	return 0; err2:	kfree(est);err1:	mutex_unlock(&xn->hash_lock);	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(par->net, info->est);} static struct xt_target xt_rateest_tg_reg[] __read_mostly = {	{		.name       = "RATEEST",		.revision   = 0,		.family     = NFPROTO_IPV4,		.target     = xt_rateest_tg,		.checkentry = xt_rateest_tg_checkentry,		.destroy    = xt_rateest_tg_destroy,		.targetsize = sizeof(struct xt_rateest_target_info),		.usersize   = offsetof(struct xt_rateest_target_info, est),		.me         = THIS_MODULE,	},#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)	{		.name       = "RATEEST",		.revision   = 0,		.family     = NFPROTO_IPV6,		.target     = xt_rateest_tg,		.checkentry = xt_rateest_tg_checkentry,		.destroy    = xt_rateest_tg_destroy,		.targetsize = sizeof(struct xt_rateest_target_info),		.usersize   = offsetof(struct xt_rateest_target_info, est),		.me         = THIS_MODULE,	},#endif}; static __net_init int xt_rateest_net_init(struct net *net){	struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);	int i; 	mutex_init(&xn->hash_lock);	for (i = 0; i < ARRAY_SIZE(xn->hash); i++)		INIT_HLIST_HEAD(&xn->hash[i]);	return 0;} static struct pernet_operations xt_rateest_net_ops = {	.init = xt_rateest_net_init,	.id   = &xt_rateest_id,	.size = sizeof(struct xt_rateest_net),}; static int __init xt_rateest_tg_init(void){	int err = register_pernet_subsys(&xt_rateest_net_ops); 	if (err)		return err;	return xt_register_targets(xt_rateest_tg_reg, ARRAY_SIZE(xt_rateest_tg_reg));} static void __exit xt_rateest_tg_fini(void){	xt_unregister_targets(xt_rateest_tg_reg, ARRAY_SIZE(xt_rateest_tg_reg));	unregister_pernet_subsys(&xt_rateest_net_ops);}  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);