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// 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, FIELD_SIZEOF(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 int
xt_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_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;
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(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, 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_UNSPEC,
.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,
};
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_target(&xt_rateest_tg_reg);
}
static void __exit xt_rateest_tg_fini(void)
{
xt_unregister_target(&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);
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