// SPDX-License-Identifier: GPL-2.0-only
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/*
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* (C) 2007 Patrick McHardy <kaber@trash.net>
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/gen_stats.h>
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#include <linux/jhash.h>
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#include <linux/rtnetlink.h>
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#include <linux/random.h>
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#include <linux/slab.h>
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#include <net/gen_stats.h>
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#include <net/netlink.h>
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#include <net/netns/generic.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_RATEEST.h>
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#include <net/netfilter/xt_rateest.h>
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#define RATEEST_HSIZE 16
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struct xt_rateest_net {
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struct mutex hash_lock;
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struct hlist_head hash[RATEEST_HSIZE];
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};
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static unsigned int xt_rateest_id;
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static unsigned int jhash_rnd __read_mostly;
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static unsigned int xt_rateest_hash(const char *name)
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{
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return jhash(name, sizeof_field(struct xt_rateest, name), jhash_rnd) &
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(RATEEST_HSIZE - 1);
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}
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static void xt_rateest_hash_insert(struct xt_rateest_net *xn,
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struct xt_rateest *est)
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{
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unsigned int h;
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h = xt_rateest_hash(est->name);
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hlist_add_head(&est->list, &xn->hash[h]);
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}
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static struct xt_rateest *__xt_rateest_lookup(struct xt_rateest_net *xn,
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const char *name)
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{
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struct xt_rateest *est;
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unsigned int h;
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h = xt_rateest_hash(name);
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hlist_for_each_entry(est, &xn->hash[h], list) {
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if (strcmp(est->name, name) == 0) {
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est->refcnt++;
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return est;
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}
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}
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return NULL;
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}
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struct xt_rateest *xt_rateest_lookup(struct net *net, const char *name)
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{
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struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);
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struct xt_rateest *est;
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mutex_lock(&xn->hash_lock);
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est = __xt_rateest_lookup(xn, name);
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mutex_unlock(&xn->hash_lock);
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return est;
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}
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EXPORT_SYMBOL_GPL(xt_rateest_lookup);
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void xt_rateest_put(struct net *net, struct xt_rateest *est)
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{
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struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);
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mutex_lock(&xn->hash_lock);
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if (--est->refcnt == 0) {
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hlist_del(&est->list);
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gen_kill_estimator(&est->rate_est);
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/*
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* gen_estimator est_timer() might access est->lock or bstats,
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* wait a RCU grace period before freeing 'est'
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*/
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kfree_rcu(est, rcu);
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}
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mutex_unlock(&xn->hash_lock);
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}
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EXPORT_SYMBOL_GPL(xt_rateest_put);
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static unsigned int
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xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_rateest_target_info *info = par->targinfo;
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struct gnet_stats_basic_packed *stats = &info->est->bstats;
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spin_lock_bh(&info->est->lock);
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stats->bytes += skb->len;
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stats->packets++;
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spin_unlock_bh(&info->est->lock);
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return XT_CONTINUE;
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}
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static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
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{
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struct xt_rateest_net *xn = net_generic(par->net, xt_rateest_id);
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struct xt_rateest_target_info *info = par->targinfo;
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struct xt_rateest *est;
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struct {
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struct nlattr opt;
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struct gnet_estimator est;
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} cfg;
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int ret;
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if (strnlen(info->name, sizeof(est->name)) >= sizeof(est->name))
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return -ENAMETOOLONG;
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net_get_random_once(&jhash_rnd, sizeof(jhash_rnd));
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mutex_lock(&xn->hash_lock);
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est = __xt_rateest_lookup(xn, info->name);
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if (est) {
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mutex_unlock(&xn->hash_lock);
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/*
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* If estimator parameters are specified, they must match the
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* existing estimator.
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*/
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if ((!info->interval && !info->ewma_log) ||
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(info->interval != est->params.interval ||
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info->ewma_log != est->params.ewma_log)) {
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xt_rateest_put(par->net, est);
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return -EINVAL;
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}
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info->est = est;
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return 0;
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}
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ret = -ENOMEM;
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est = kzalloc(sizeof(*est), GFP_KERNEL);
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if (!est)
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goto err1;
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strlcpy(est->name, info->name, sizeof(est->name));
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spin_lock_init(&est->lock);
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est->refcnt = 1;
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est->params.interval = info->interval;
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est->params.ewma_log = info->ewma_log;
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cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est));
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cfg.opt.nla_type = TCA_STATS_RATE_EST;
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cfg.est.interval = info->interval;
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cfg.est.ewma_log = info->ewma_log;
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ret = gen_new_estimator(&est->bstats, NULL, &est->rate_est,
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&est->lock, NULL, &cfg.opt);
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if (ret < 0)
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goto err2;
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info->est = est;
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xt_rateest_hash_insert(xn, est);
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mutex_unlock(&xn->hash_lock);
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return 0;
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err2:
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kfree(est);
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err1:
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mutex_unlock(&xn->hash_lock);
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return ret;
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}
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static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
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{
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struct xt_rateest_target_info *info = par->targinfo;
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xt_rateest_put(par->net, info->est);
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}
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static struct xt_target xt_rateest_tg_reg __read_mostly = {
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.name = "RATEEST",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.target = xt_rateest_tg,
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.checkentry = xt_rateest_tg_checkentry,
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.destroy = xt_rateest_tg_destroy,
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.targetsize = sizeof(struct xt_rateest_target_info),
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.usersize = offsetof(struct xt_rateest_target_info, est),
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.me = THIS_MODULE,
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};
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static __net_init int xt_rateest_net_init(struct net *net)
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{
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struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);
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int i;
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mutex_init(&xn->hash_lock);
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for (i = 0; i < ARRAY_SIZE(xn->hash); i++)
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INIT_HLIST_HEAD(&xn->hash[i]);
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return 0;
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}
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static struct pernet_operations xt_rateest_net_ops = {
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.init = xt_rateest_net_init,
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.id = &xt_rateest_id,
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.size = sizeof(struct xt_rateest_net),
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};
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static int __init xt_rateest_tg_init(void)
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{
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int err = register_pernet_subsys(&xt_rateest_net_ops);
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if (err)
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return err;
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return xt_register_target(&xt_rateest_tg_reg);
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}
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static void __exit xt_rateest_tg_fini(void)
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{
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xt_unregister_target(&xt_rateest_tg_reg);
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unregister_pernet_subsys(&xt_rateest_net_ops);
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}
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Xtables: packet rate estimator");
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MODULE_ALIAS("ipt_RATEEST");
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MODULE_ALIAS("ip6t_RATEEST");
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module_init(xt_rateest_tg_init);
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module_exit(xt_rateest_tg_fini);
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