linux-stable/net/netfilter/xt_rateest.c
Eric Dumazet 1c0d32fde5 net_sched: gen_estimator: complete rewrite of rate estimators
1) Old code was hard to maintain, due to complex lock chains.
   (We probably will be able to remove some kfree_rcu() in callers)

2) Using a single timer to update all estimators does not scale.

3) Code was buggy on 32bit kernel (WRITE_ONCE() on 64bit quantity
   is not supposed to work well)

In this rewrite :

- I removed the RB tree that had to be scanned in
  gen_estimator_active(). qdisc dumps should be much faster.

- Each estimator has its own timer.

- Estimations are maintained in net_rate_estimator structure,
  instead of dirtying the qdisc. Minor, but part of the simplification.

- Reading the estimator uses RCU and a seqcount to provide proper
  support for 32bit kernels.

- We reduce memory need when estimators are not used, since
  we store a pointer, instead of the bytes/packets counters.

- xt_rateest_mt() no longer has to grab a spinlock.
  (In the future, xt_rateest_tg() could be switched to per cpu counters)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-05 15:21:59 -05:00

155 lines
3.7 KiB
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/netfilter/x_tables.h>
#include <linux/netfilter/xt_rateest.h>
#include <net/netfilter/xt_rateest.h>
static bool
xt_rateest_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct xt_rateest_match_info *info = par->matchinfo;
struct gnet_stats_rate_est64 sample = {0};
u_int32_t bps1, bps2, pps1, pps2;
bool ret = true;
gen_estimator_read(&info->est1->rate_est, &sample);
if (info->flags & XT_RATEEST_MATCH_DELTA) {
bps1 = info->bps1 >= sample.bps ? info->bps1 - sample.bps : 0;
pps1 = info->pps1 >= sample.pps ? info->pps1 - sample.pps : 0;
} else {
bps1 = sample.bps;
pps1 = sample.pps;
}
if (info->flags & XT_RATEEST_MATCH_ABS) {
bps2 = info->bps2;
pps2 = info->pps2;
} else {
gen_estimator_read(&info->est2->rate_est, &sample);
if (info->flags & XT_RATEEST_MATCH_DELTA) {
bps2 = info->bps2 >= sample.bps ? info->bps2 - sample.bps : 0;
pps2 = info->pps2 >= sample.pps ? info->pps2 - sample.pps : 0;
} else {
bps2 = sample.bps;
pps2 = sample.pps;
}
}
switch (info->mode) {
case XT_RATEEST_MATCH_LT:
if (info->flags & XT_RATEEST_MATCH_BPS)
ret &= bps1 < bps2;
if (info->flags & XT_RATEEST_MATCH_PPS)
ret &= pps1 < pps2;
break;
case XT_RATEEST_MATCH_GT:
if (info->flags & XT_RATEEST_MATCH_BPS)
ret &= bps1 > bps2;
if (info->flags & XT_RATEEST_MATCH_PPS)
ret &= pps1 > pps2;
break;
case XT_RATEEST_MATCH_EQ:
if (info->flags & XT_RATEEST_MATCH_BPS)
ret &= bps1 == bps2;
if (info->flags & XT_RATEEST_MATCH_PPS)
ret &= pps1 == pps2;
break;
}
ret ^= info->flags & XT_RATEEST_MATCH_INVERT ? true : false;
return ret;
}
static int xt_rateest_mt_checkentry(const struct xt_mtchk_param *par)
{
struct xt_rateest_match_info *info = par->matchinfo;
struct xt_rateest *est1, *est2;
int ret = -EINVAL;
if (hweight32(info->flags & (XT_RATEEST_MATCH_ABS |
XT_RATEEST_MATCH_REL)) != 1)
goto err1;
if (!(info->flags & (XT_RATEEST_MATCH_BPS | XT_RATEEST_MATCH_PPS)))
goto err1;
switch (info->mode) {
case XT_RATEEST_MATCH_EQ:
case XT_RATEEST_MATCH_LT:
case XT_RATEEST_MATCH_GT:
break;
default:
goto err1;
}
ret = -ENOENT;
est1 = xt_rateest_lookup(info->name1);
if (!est1)
goto err1;
est2 = NULL;
if (info->flags & XT_RATEEST_MATCH_REL) {
est2 = xt_rateest_lookup(info->name2);
if (!est2)
goto err2;
}
info->est1 = est1;
info->est2 = est2;
return 0;
err2:
xt_rateest_put(est1);
err1:
return ret;
}
static void xt_rateest_mt_destroy(const struct xt_mtdtor_param *par)
{
struct xt_rateest_match_info *info = par->matchinfo;
xt_rateest_put(info->est1);
if (info->est2)
xt_rateest_put(info->est2);
}
static struct xt_match xt_rateest_mt_reg __read_mostly = {
.name = "rateest",
.revision = 0,
.family = NFPROTO_UNSPEC,
.match = xt_rateest_mt,
.checkentry = xt_rateest_mt_checkentry,
.destroy = xt_rateest_mt_destroy,
.matchsize = sizeof(struct xt_rateest_match_info),
.me = THIS_MODULE,
};
static int __init xt_rateest_mt_init(void)
{
return xt_register_match(&xt_rateest_mt_reg);
}
static void __exit xt_rateest_mt_fini(void)
{
xt_unregister_match(&xt_rateest_mt_reg);
}
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("xtables rate estimator match");
MODULE_ALIAS("ipt_rateest");
MODULE_ALIAS("ip6t_rateest");
module_init(xt_rateest_mt_init);
module_exit(xt_rateest_mt_fini);