// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* ip_vs_est.c: simple rate estimator for IPVS
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*
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* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
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*
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* Changes: Hans Schillstrom <hans.schillstrom@ericsson.com>
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* Network name space (netns) aware.
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* Global data moved to netns i.e struct netns_ipvs
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* Affected data: est_list and est_lock.
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* estimation_timer() runs with timer per netns.
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* get_stats()) do the per cpu summing.
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*/
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#define KMSG_COMPONENT "IPVS"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/kernel.h>
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#include <linux/jiffies.h>
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#include <linux/types.h>
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#include <linux/interrupt.h>
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#include <linux/sysctl.h>
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#include <linux/list.h>
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#include <net/ip_vs.h>
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/*
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This code is to estimate rate in a shorter interval (such as 8
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seconds) for virtual services and real servers. For measure rate in a
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long interval, it is easy to implement a user level daemon which
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periodically reads those statistical counters and measure rate.
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Currently, the measurement is activated by slow timer handler. Hope
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this measurement will not introduce too much load.
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We measure rate during the last 8 seconds every 2 seconds:
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avgrate = avgrate*(1-W) + rate*W
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where W = 2^(-2)
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NOTES.
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* Average bps is scaled by 2^5, while average pps and cps are scaled by 2^10.
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* Netlink users can see 64-bit values but sockopt users are restricted
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to 32-bit values for conns, packets, bps, cps and pps.
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* A lot of code is taken from net/core/gen_estimator.c
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*/
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/*
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* Make a summary from each cpu
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*/
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static void ip_vs_read_cpu_stats(struct ip_vs_kstats *sum,
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struct ip_vs_cpu_stats __percpu *stats)
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{
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int i;
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bool add = false;
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for_each_possible_cpu(i) {
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struct ip_vs_cpu_stats *s = per_cpu_ptr(stats, i);
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unsigned int start;
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u64 conns, inpkts, outpkts, inbytes, outbytes;
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if (add) {
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do {
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start = u64_stats_fetch_begin(&s->syncp);
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conns = s->cnt.conns;
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inpkts = s->cnt.inpkts;
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outpkts = s->cnt.outpkts;
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inbytes = s->cnt.inbytes;
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outbytes = s->cnt.outbytes;
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} while (u64_stats_fetch_retry(&s->syncp, start));
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sum->conns += conns;
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sum->inpkts += inpkts;
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sum->outpkts += outpkts;
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sum->inbytes += inbytes;
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sum->outbytes += outbytes;
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} else {
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add = true;
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do {
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start = u64_stats_fetch_begin(&s->syncp);
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sum->conns = s->cnt.conns;
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sum->inpkts = s->cnt.inpkts;
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sum->outpkts = s->cnt.outpkts;
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sum->inbytes = s->cnt.inbytes;
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sum->outbytes = s->cnt.outbytes;
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} while (u64_stats_fetch_retry(&s->syncp, start));
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}
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}
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}
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static void estimation_timer(struct timer_list *t)
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{
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struct ip_vs_estimator *e;
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struct ip_vs_stats *s;
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u64 rate;
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struct netns_ipvs *ipvs = from_timer(ipvs, t, est_timer);
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spin_lock(&ipvs->est_lock);
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list_for_each_entry(e, &ipvs->est_list, list) {
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s = container_of(e, struct ip_vs_stats, est);
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spin_lock(&s->lock);
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ip_vs_read_cpu_stats(&s->kstats, s->cpustats);
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/* scaled by 2^10, but divided 2 seconds */
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rate = (s->kstats.conns - e->last_conns) << 9;
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e->last_conns = s->kstats.conns;
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e->cps += ((s64)rate - (s64)e->cps) >> 2;
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rate = (s->kstats.inpkts - e->last_inpkts) << 9;
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e->last_inpkts = s->kstats.inpkts;
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e->inpps += ((s64)rate - (s64)e->inpps) >> 2;
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rate = (s->kstats.outpkts - e->last_outpkts) << 9;
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e->last_outpkts = s->kstats.outpkts;
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e->outpps += ((s64)rate - (s64)e->outpps) >> 2;
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/* scaled by 2^5, but divided 2 seconds */
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rate = (s->kstats.inbytes - e->last_inbytes) << 4;
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e->last_inbytes = s->kstats.inbytes;
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e->inbps += ((s64)rate - (s64)e->inbps) >> 2;
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rate = (s->kstats.outbytes - e->last_outbytes) << 4;
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e->last_outbytes = s->kstats.outbytes;
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e->outbps += ((s64)rate - (s64)e->outbps) >> 2;
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spin_unlock(&s->lock);
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}
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spin_unlock(&ipvs->est_lock);
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mod_timer(&ipvs->est_timer, jiffies + 2*HZ);
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}
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void ip_vs_start_estimator(struct netns_ipvs *ipvs, struct ip_vs_stats *stats)
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{
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struct ip_vs_estimator *est = &stats->est;
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INIT_LIST_HEAD(&est->list);
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spin_lock_bh(&ipvs->est_lock);
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list_add(&est->list, &ipvs->est_list);
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spin_unlock_bh(&ipvs->est_lock);
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}
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void ip_vs_stop_estimator(struct netns_ipvs *ipvs, struct ip_vs_stats *stats)
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{
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struct ip_vs_estimator *est = &stats->est;
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spin_lock_bh(&ipvs->est_lock);
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list_del(&est->list);
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spin_unlock_bh(&ipvs->est_lock);
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}
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void ip_vs_zero_estimator(struct ip_vs_stats *stats)
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{
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struct ip_vs_estimator *est = &stats->est;
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struct ip_vs_kstats *k = &stats->kstats;
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/* reset counters, caller must hold the stats->lock lock */
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est->last_inbytes = k->inbytes;
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est->last_outbytes = k->outbytes;
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est->last_conns = k->conns;
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est->last_inpkts = k->inpkts;
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est->last_outpkts = k->outpkts;
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est->cps = 0;
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est->inpps = 0;
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est->outpps = 0;
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est->inbps = 0;
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est->outbps = 0;
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}
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/* Get decoded rates */
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void ip_vs_read_estimator(struct ip_vs_kstats *dst, struct ip_vs_stats *stats)
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{
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struct ip_vs_estimator *e = &stats->est;
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dst->cps = (e->cps + 0x1FF) >> 10;
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dst->inpps = (e->inpps + 0x1FF) >> 10;
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dst->outpps = (e->outpps + 0x1FF) >> 10;
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dst->inbps = (e->inbps + 0xF) >> 5;
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dst->outbps = (e->outbps + 0xF) >> 5;
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}
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int __net_init ip_vs_estimator_net_init(struct netns_ipvs *ipvs)
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{
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INIT_LIST_HEAD(&ipvs->est_list);
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spin_lock_init(&ipvs->est_lock);
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timer_setup(&ipvs->est_timer, estimation_timer, 0);
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mod_timer(&ipvs->est_timer, jiffies + 2 * HZ);
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return 0;
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}
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void __net_exit ip_vs_estimator_net_cleanup(struct netns_ipvs *ipvs)
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{
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del_timer_sync(&ipvs->est_timer);
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}
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