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1/*
2 * net/sched/gen_estimator.c Simple rate estimator.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 * Eric Dumazet <edumazet@google.com>
11 *
12 * Changes:
13 * Jamal Hadi Salim - moved it to net/core and reshulfed
14 * names to make it usable in general net subsystem.
15 */
16
17#include <linux/uaccess.h>
18#include <linux/bitops.h>
19#include <linux/module.h>
20#include <linux/types.h>
21#include <linux/kernel.h>
22#include <linux/jiffies.h>
23#include <linux/string.h>
24#include <linux/mm.h>
25#include <linux/socket.h>
26#include <linux/sockios.h>
27#include <linux/in.h>
28#include <linux/errno.h>
29#include <linux/interrupt.h>
30#include <linux/netdevice.h>
31#include <linux/skbuff.h>
32#include <linux/rtnetlink.h>
33#include <linux/init.h>
34#include <linux/slab.h>
35#include <linux/seqlock.h>
36#include <net/sock.h>
37#include <net/gen_stats.h>
38
39/* This code is NOT intended to be used for statistics collection,
40 * its purpose is to provide a base for statistical multiplexing
41 * for controlled load service.
42 * If you need only statistics, run a user level daemon which
43 * periodically reads byte counters.
44 */
45
46struct net_rate_estimator {
47 struct gnet_stats_basic_packed *bstats;
48 spinlock_t *stats_lock;
49 seqcount_t *running;
50 struct gnet_stats_basic_cpu __percpu *cpu_bstats;
51 u8 ewma_log;
52 u8 intvl_log; /* period : (250ms << intvl_log) */
53
54 seqcount_t seq;
55 u32 last_packets;
56 u64 last_bytes;
57
58 u64 avpps;
59 u64 avbps;
60
61 unsigned long next_jiffies;
62 struct timer_list timer;
63 struct rcu_head rcu;
64};
65
66static void est_fetch_counters(struct net_rate_estimator *e,
67 struct gnet_stats_basic_packed *b)
68{
69 memset(b, 0, sizeof(*b));
70 if (e->stats_lock)
71 spin_lock(e->stats_lock);
72
73 __gnet_stats_copy_basic(e->running, b, e->cpu_bstats, e->bstats);
74
75 if (e->stats_lock)
76 spin_unlock(e->stats_lock);
77
78}
79
80static void est_timer(struct timer_list *t)
81{
82 struct net_rate_estimator *est = from_timer(est, t, timer);
83 struct gnet_stats_basic_packed b;
84 u64 rate, brate;
85
86 est_fetch_counters(est, &b);
87 brate = (b.bytes - est->last_bytes) << (10 - est->ewma_log - est->intvl_log);
88 brate -= (est->avbps >> est->ewma_log);
89
90 rate = (u64)(b.packets - est->last_packets) << (10 - est->ewma_log - est->intvl_log);
91 rate -= (est->avpps >> est->ewma_log);
92
93 write_seqcount_begin(&est->seq);
94 est->avbps += brate;
95 est->avpps += rate;
96 write_seqcount_end(&est->seq);
97
98 est->last_bytes = b.bytes;
99 est->last_packets = b.packets;
100
101 est->next_jiffies += ((HZ/4) << est->intvl_log);
102
103 if (unlikely(time_after_eq(jiffies, est->next_jiffies))) {
104 /* Ouch... timer was delayed. */
105 est->next_jiffies = jiffies + 1;
106 }
107 mod_timer(&est->timer, est->next_jiffies);
108}
109
110/**
111 * gen_new_estimator - create a new rate estimator
112 * @bstats: basic statistics
113 * @cpu_bstats: bstats per cpu
114 * @rate_est: rate estimator statistics
115 * @stats_lock: statistics lock
116 * @running: qdisc running seqcount
117 * @opt: rate estimator configuration TLV
118 *
119 * Creates a new rate estimator with &bstats as source and &rate_est
120 * as destination. A new timer with the interval specified in the
121 * configuration TLV is created. Upon each interval, the latest statistics
122 * will be read from &bstats and the estimated rate will be stored in
123 * &rate_est with the statistics lock grabbed during this period.
124 *
125 * Returns 0 on success or a negative error code.
126 *
127 */
128int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
129 struct gnet_stats_basic_cpu __percpu *cpu_bstats,
130 struct net_rate_estimator __rcu **rate_est,
131 spinlock_t *stats_lock,
132 seqcount_t *running,
133 struct nlattr *opt)
134{
135 struct gnet_estimator *parm = nla_data(opt);
136 struct net_rate_estimator *old, *est;
137 struct gnet_stats_basic_packed b;
138 int intvl_log;
139
140 if (nla_len(opt) < sizeof(*parm))
141 return -EINVAL;
142
143 /* allowed timer periods are :
144 * -2 : 250ms, -1 : 500ms, 0 : 1 sec
145 * 1 : 2 sec, 2 : 4 sec, 3 : 8 sec
146 */
147 if (parm->interval < -2 || parm->interval > 3)
148 return -EINVAL;
149
150 est = kzalloc(sizeof(*est), GFP_KERNEL);
151 if (!est)
152 return -ENOBUFS;
153
154 seqcount_init(&est->seq);
155 intvl_log = parm->interval + 2;
156 est->bstats = bstats;
157 est->stats_lock = stats_lock;
158 est->running = running;
159 est->ewma_log = parm->ewma_log;
160 est->intvl_log = intvl_log;
161 est->cpu_bstats = cpu_bstats;
162
163 if (stats_lock)
164 local_bh_disable();
165 est_fetch_counters(est, &b);
166 if (stats_lock)
167 local_bh_enable();
168 est->last_bytes = b.bytes;
169 est->last_packets = b.packets;
170 old = rcu_dereference_protected(*rate_est, 1);
171 if (old) {
172 del_timer_sync(&old->timer);
173 est->avbps = old->avbps;
174 est->avpps = old->avpps;
175 }
176
177 est->next_jiffies = jiffies + ((HZ/4) << intvl_log);
178 timer_setup(&est->timer, est_timer, 0);
179 mod_timer(&est->timer, est->next_jiffies);
180
181 rcu_assign_pointer(*rate_est, est);
182 if (old)
183 kfree_rcu(old, rcu);
184 return 0;
185}
186EXPORT_SYMBOL(gen_new_estimator);
187
188/**
189 * gen_kill_estimator - remove a rate estimator
190 * @rate_est: rate estimator
191 *
192 * Removes the rate estimator.
193 *
194 */
195void gen_kill_estimator(struct net_rate_estimator __rcu **rate_est)
196{
197 struct net_rate_estimator *est;
198
199 est = xchg((__force struct net_rate_estimator **)rate_est, NULL);
200 if (est) {
201 del_timer_sync(&est->timer);
202 kfree_rcu(est, rcu);
203 }
204}
205EXPORT_SYMBOL(gen_kill_estimator);
206
207/**
208 * gen_replace_estimator - replace rate estimator configuration
209 * @bstats: basic statistics
210 * @cpu_bstats: bstats per cpu
211 * @rate_est: rate estimator statistics
212 * @stats_lock: statistics lock
213 * @running: qdisc running seqcount (might be NULL)
214 * @opt: rate estimator configuration TLV
215 *
216 * Replaces the configuration of a rate estimator by calling
217 * gen_kill_estimator() and gen_new_estimator().
218 *
219 * Returns 0 on success or a negative error code.
220 */
221int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
222 struct gnet_stats_basic_cpu __percpu *cpu_bstats,
223 struct net_rate_estimator __rcu **rate_est,
224 spinlock_t *stats_lock,
225 seqcount_t *running, struct nlattr *opt)
226{
227 return gen_new_estimator(bstats, cpu_bstats, rate_est,
228 stats_lock, running, opt);
229}
230EXPORT_SYMBOL(gen_replace_estimator);
231
232/**
233 * gen_estimator_active - test if estimator is currently in use
234 * @rate_est: rate estimator
235 *
236 * Returns true if estimator is active, and false if not.
237 */
238bool gen_estimator_active(struct net_rate_estimator __rcu **rate_est)
239{
240 return !!rcu_access_pointer(*rate_est);
241}
242EXPORT_SYMBOL(gen_estimator_active);
243
244bool gen_estimator_read(struct net_rate_estimator __rcu **rate_est,
245 struct gnet_stats_rate_est64 *sample)
246{
247 struct net_rate_estimator *est;
248 unsigned seq;
249
250 rcu_read_lock();
251 est = rcu_dereference(*rate_est);
252 if (!est) {
253 rcu_read_unlock();
254 return false;
255 }
256
257 do {
258 seq = read_seqcount_begin(&est->seq);
259 sample->bps = est->avbps >> 8;
260 sample->pps = est->avpps >> 8;
261 } while (read_seqcount_retry(&est->seq, seq));
262
263 rcu_read_unlock();
264 return true;
265}
266EXPORT_SYMBOL(gen_estimator_read);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/gen_estimator.c Simple rate estimator.
4 *
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 * Eric Dumazet <edumazet@google.com>
7 *
8 * Changes:
9 * Jamal Hadi Salim - moved it to net/core and reshulfed
10 * names to make it usable in general net subsystem.
11 */
12
13#include <linux/uaccess.h>
14#include <linux/bitops.h>
15#include <linux/module.h>
16#include <linux/types.h>
17#include <linux/kernel.h>
18#include <linux/jiffies.h>
19#include <linux/string.h>
20#include <linux/mm.h>
21#include <linux/socket.h>
22#include <linux/sockios.h>
23#include <linux/in.h>
24#include <linux/errno.h>
25#include <linux/interrupt.h>
26#include <linux/netdevice.h>
27#include <linux/skbuff.h>
28#include <linux/rtnetlink.h>
29#include <linux/init.h>
30#include <linux/slab.h>
31#include <linux/seqlock.h>
32#include <net/sock.h>
33#include <net/gen_stats.h>
34
35/* This code is NOT intended to be used for statistics collection,
36 * its purpose is to provide a base for statistical multiplexing
37 * for controlled load service.
38 * If you need only statistics, run a user level daemon which
39 * periodically reads byte counters.
40 */
41
42struct net_rate_estimator {
43 struct gnet_stats_basic_packed *bstats;
44 spinlock_t *stats_lock;
45 seqcount_t *running;
46 struct gnet_stats_basic_cpu __percpu *cpu_bstats;
47 u8 ewma_log;
48 u8 intvl_log; /* period : (250ms << intvl_log) */
49
50 seqcount_t seq;
51 u64 last_packets;
52 u64 last_bytes;
53
54 u64 avpps;
55 u64 avbps;
56
57 unsigned long next_jiffies;
58 struct timer_list timer;
59 struct rcu_head rcu;
60};
61
62static void est_fetch_counters(struct net_rate_estimator *e,
63 struct gnet_stats_basic_packed *b)
64{
65 memset(b, 0, sizeof(*b));
66 if (e->stats_lock)
67 spin_lock(e->stats_lock);
68
69 __gnet_stats_copy_basic(e->running, b, e->cpu_bstats, e->bstats);
70
71 if (e->stats_lock)
72 spin_unlock(e->stats_lock);
73
74}
75
76static void est_timer(struct timer_list *t)
77{
78 struct net_rate_estimator *est = from_timer(est, t, timer);
79 struct gnet_stats_basic_packed b;
80 u64 rate, brate;
81
82 est_fetch_counters(est, &b);
83 brate = (b.bytes - est->last_bytes) << (10 - est->ewma_log - est->intvl_log);
84 brate -= (est->avbps >> est->ewma_log);
85
86 rate = (b.packets - est->last_packets) << (10 - est->ewma_log - est->intvl_log);
87 rate -= (est->avpps >> est->ewma_log);
88
89 write_seqcount_begin(&est->seq);
90 est->avbps += brate;
91 est->avpps += rate;
92 write_seqcount_end(&est->seq);
93
94 est->last_bytes = b.bytes;
95 est->last_packets = b.packets;
96
97 est->next_jiffies += ((HZ/4) << est->intvl_log);
98
99 if (unlikely(time_after_eq(jiffies, est->next_jiffies))) {
100 /* Ouch... timer was delayed. */
101 est->next_jiffies = jiffies + 1;
102 }
103 mod_timer(&est->timer, est->next_jiffies);
104}
105
106/**
107 * gen_new_estimator - create a new rate estimator
108 * @bstats: basic statistics
109 * @cpu_bstats: bstats per cpu
110 * @rate_est: rate estimator statistics
111 * @lock: lock for statistics and control path
112 * @running: qdisc running seqcount
113 * @opt: rate estimator configuration TLV
114 *
115 * Creates a new rate estimator with &bstats as source and &rate_est
116 * as destination. A new timer with the interval specified in the
117 * configuration TLV is created. Upon each interval, the latest statistics
118 * will be read from &bstats and the estimated rate will be stored in
119 * &rate_est with the statistics lock grabbed during this period.
120 *
121 * Returns 0 on success or a negative error code.
122 *
123 */
124int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
125 struct gnet_stats_basic_cpu __percpu *cpu_bstats,
126 struct net_rate_estimator __rcu **rate_est,
127 spinlock_t *lock,
128 seqcount_t *running,
129 struct nlattr *opt)
130{
131 struct gnet_estimator *parm = nla_data(opt);
132 struct net_rate_estimator *old, *est;
133 struct gnet_stats_basic_packed b;
134 int intvl_log;
135
136 if (nla_len(opt) < sizeof(*parm))
137 return -EINVAL;
138
139 /* allowed timer periods are :
140 * -2 : 250ms, -1 : 500ms, 0 : 1 sec
141 * 1 : 2 sec, 2 : 4 sec, 3 : 8 sec
142 */
143 if (parm->interval < -2 || parm->interval > 3)
144 return -EINVAL;
145
146 est = kzalloc(sizeof(*est), GFP_KERNEL);
147 if (!est)
148 return -ENOBUFS;
149
150 seqcount_init(&est->seq);
151 intvl_log = parm->interval + 2;
152 est->bstats = bstats;
153 est->stats_lock = lock;
154 est->running = running;
155 est->ewma_log = parm->ewma_log;
156 est->intvl_log = intvl_log;
157 est->cpu_bstats = cpu_bstats;
158
159 if (lock)
160 local_bh_disable();
161 est_fetch_counters(est, &b);
162 if (lock)
163 local_bh_enable();
164 est->last_bytes = b.bytes;
165 est->last_packets = b.packets;
166
167 if (lock)
168 spin_lock_bh(lock);
169 old = rcu_dereference_protected(*rate_est, 1);
170 if (old) {
171 del_timer_sync(&old->timer);
172 est->avbps = old->avbps;
173 est->avpps = old->avpps;
174 }
175
176 est->next_jiffies = jiffies + ((HZ/4) << intvl_log);
177 timer_setup(&est->timer, est_timer, 0);
178 mod_timer(&est->timer, est->next_jiffies);
179
180 rcu_assign_pointer(*rate_est, est);
181 if (lock)
182 spin_unlock_bh(lock);
183 if (old)
184 kfree_rcu(old, rcu);
185 return 0;
186}
187EXPORT_SYMBOL(gen_new_estimator);
188
189/**
190 * gen_kill_estimator - remove a rate estimator
191 * @rate_est: rate estimator
192 *
193 * Removes the rate estimator.
194 *
195 */
196void gen_kill_estimator(struct net_rate_estimator __rcu **rate_est)
197{
198 struct net_rate_estimator *est;
199
200 est = xchg((__force struct net_rate_estimator **)rate_est, NULL);
201 if (est) {
202 del_timer_sync(&est->timer);
203 kfree_rcu(est, rcu);
204 }
205}
206EXPORT_SYMBOL(gen_kill_estimator);
207
208/**
209 * gen_replace_estimator - replace rate estimator configuration
210 * @bstats: basic statistics
211 * @cpu_bstats: bstats per cpu
212 * @rate_est: rate estimator statistics
213 * @lock: lock for statistics and control path
214 * @running: qdisc running seqcount (might be NULL)
215 * @opt: rate estimator configuration TLV
216 *
217 * Replaces the configuration of a rate estimator by calling
218 * gen_kill_estimator() and gen_new_estimator().
219 *
220 * Returns 0 on success or a negative error code.
221 */
222int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
223 struct gnet_stats_basic_cpu __percpu *cpu_bstats,
224 struct net_rate_estimator __rcu **rate_est,
225 spinlock_t *lock,
226 seqcount_t *running, struct nlattr *opt)
227{
228 return gen_new_estimator(bstats, cpu_bstats, rate_est,
229 lock, running, opt);
230}
231EXPORT_SYMBOL(gen_replace_estimator);
232
233/**
234 * gen_estimator_active - test if estimator is currently in use
235 * @rate_est: rate estimator
236 *
237 * Returns true if estimator is active, and false if not.
238 */
239bool gen_estimator_active(struct net_rate_estimator __rcu **rate_est)
240{
241 return !!rcu_access_pointer(*rate_est);
242}
243EXPORT_SYMBOL(gen_estimator_active);
244
245bool gen_estimator_read(struct net_rate_estimator __rcu **rate_est,
246 struct gnet_stats_rate_est64 *sample)
247{
248 struct net_rate_estimator *est;
249 unsigned seq;
250
251 rcu_read_lock();
252 est = rcu_dereference(*rate_est);
253 if (!est) {
254 rcu_read_unlock();
255 return false;
256 }
257
258 do {
259 seq = read_seqcount_begin(&est->seq);
260 sample->bps = est->avbps >> 8;
261 sample->pps = est->avpps >> 8;
262 } while (read_seqcount_retry(&est->seq, seq));
263
264 rcu_read_unlock();
265 return true;
266}
267EXPORT_SYMBOL(gen_estimator_read);