1 files changed, 278 insertions, 0 deletions
diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
new file mode 100644
index 000000000..fae9c4694
--- /dev/null
+++ b/net/core/gen_estimator.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * net/sched/gen_estimator.c	Simple rate estimator.
+ *
+ * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ *		Eric Dumazet <edumazet@google.com>
+ *
+ * Changes:
+ *              Jamal Hadi Salim - moved it to net/core and reshulfed
+ *              names to make it usable in general net subsystem.
+ */
+
+#include <linux/uaccess.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/jiffies.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/in.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/seqlock.h>
+#include <net/sock.h>
+#include <net/gen_stats.h>
+
+/* This code is NOT intended to be used for statistics collection,
+ * its purpose is to provide a base for statistical multiplexing
+ * for controlled load service.
+ * If you need only statistics, run a user level daemon which
+ * periodically reads byte counters.
+ */
+
+struct net_rate_estimator {
+	struct gnet_stats_basic_sync	*bstats;
+	spinlock_t		*stats_lock;
+	bool			running;
+	struct gnet_stats_basic_sync __percpu *cpu_bstats;
+	u8			ewma_log;
+	u8			intvl_log; /* period : (250ms << intvl_log) */
+
+	seqcount_t		seq;
+	u64			last_packets;
+	u64			last_bytes;
+
+	u64			avpps;
+	u64			avbps;
+
+	unsigned long           next_jiffies;
+	struct timer_list       timer;
+	struct rcu_head		rcu;
+};
+
+static void est_fetch_counters(struct net_rate_estimator *e,
+			       struct gnet_stats_basic_sync *b)
+{
+	gnet_stats_basic_sync_init(b);
+	if (e->stats_lock)
+		spin_lock(e->stats_lock);
+
+	gnet_stats_add_basic(b, e->cpu_bstats, e->bstats, e->running);
+
+	if (e->stats_lock)
+		spin_unlock(e->stats_lock);
+
+}
+
+static void est_timer(struct timer_list *t)
+{
+	struct net_rate_estimator *est = from_timer(est, t, timer);
+	struct gnet_stats_basic_sync b;
+	u64 b_bytes, b_packets;
+	u64 rate, brate;
+
+	est_fetch_counters(est, &b);
+	b_bytes = u64_stats_read(&b.bytes);
+	b_packets = u64_stats_read(&b.packets);
+
+	brate = (b_bytes - est->last_bytes) << (10 - est->intvl_log);
+	brate = (brate >> est->ewma_log) - (est->avbps >> est->ewma_log);
+
+	rate = (b_packets - est->last_packets) << (10 - est->intvl_log);
+	rate = (rate >> est->ewma_log) - (est->avpps >> est->ewma_log);
+
+	write_seqcount_begin(&est->seq);
+	est->avbps += brate;
+	est->avpps += rate;
+	write_seqcount_end(&est->seq);
+
+	est->last_bytes = b_bytes;
+	est->last_packets = b_packets;
+
+	est->next_jiffies += ((HZ/4) << est->intvl_log);
+
+	if (unlikely(time_after_eq(jiffies, est->next_jiffies))) {
+		/* Ouch... timer was delayed. */
+		est->next_jiffies = jiffies + 1;
+	}
+	mod_timer(&est->timer, est->next_jiffies);
+}
+
+/**
+ * gen_new_estimator - create a new rate estimator
+ * @bstats: basic statistics
+ * @cpu_bstats: bstats per cpu
+ * @rate_est: rate estimator statistics
+ * @lock: lock for statistics and control path
+ * @running: true if @bstats represents a running qdisc, thus @bstats'
+ *           internal values might change during basic reads. Only used
+ *           if @bstats_cpu is NULL
+ * @opt: rate estimator configuration TLV
+ *
+ * Creates a new rate estimator with &bstats as source and &rate_est
+ * as destination. A new timer with the interval specified in the
+ * configuration TLV is created. Upon each interval, the latest statistics
+ * will be read from &bstats and the estimated rate will be stored in
+ * &rate_est with the statistics lock grabbed during this period.
+ *
+ * Returns 0 on success or a negative error code.
+ *
+ */
+int gen_new_estimator(struct gnet_stats_basic_sync *bstats,
+		      struct gnet_stats_basic_sync __percpu *cpu_bstats,
+		      struct net_rate_estimator __rcu **rate_est,
+		      spinlock_t *lock,
+		      bool running,
+		      struct nlattr *opt)
+{
+	struct gnet_estimator *parm = nla_data(opt);
+	struct net_rate_estimator *old, *est;
+	struct gnet_stats_basic_sync b;
+	int intvl_log;
+
+	if (nla_len(opt) < sizeof(*parm))
+		return -EINVAL;
+
+	/* allowed timer periods are :
+	 * -2 : 250ms,   -1 : 500ms,    0 : 1 sec
+	 *  1 : 2 sec,    2 : 4 sec,    3 : 8 sec
+	 */
+	if (parm->interval < -2 || parm->interval > 3)
+		return -EINVAL;
+
+	if (parm->ewma_log == 0 || parm->ewma_log >= 31)
+		return -EINVAL;
+
+	est = kzalloc(sizeof(*est), GFP_KERNEL);
+	if (!est)
+		return -ENOBUFS;
+
+	seqcount_init(&est->seq);
+	intvl_log = parm->interval + 2;
+	est->bstats = bstats;
+	est->stats_lock = lock;
+	est->running  = running;
+	est->ewma_log = parm->ewma_log;
+	est->intvl_log = intvl_log;
+	est->cpu_bstats = cpu_bstats;
+
+	if (lock)
+		local_bh_disable();
+	est_fetch_counters(est, &b);
+	if (lock)
+		local_bh_enable();
+	est->last_bytes = u64_stats_read(&b.bytes);
+	est->last_packets = u64_stats_read(&b.packets);
+
+	if (lock)
+		spin_lock_bh(lock);
+	old = rcu_dereference_protected(*rate_est, 1);
+	if (old) {
+		del_timer_sync(&old->timer);
+		est->avbps = old->avbps;
+		est->avpps = old->avpps;
+	}
+
+	est->next_jiffies = jiffies + ((HZ/4) << intvl_log);
+	timer_setup(&est->timer, est_timer, 0);
+	mod_timer(&est->timer, est->next_jiffies);
+
+	rcu_assign_pointer(*rate_est, est);
+	if (lock)
+		spin_unlock_bh(lock);
+	if (old)
+		kfree_rcu(old, rcu);
+	return 0;
+}
+EXPORT_SYMBOL(gen_new_estimator);
+
+/**
+ * gen_kill_estimator - remove a rate estimator
+ * @rate_est: rate estimator
+ *
+ * Removes the rate estimator.
+ *
+ */
+void gen_kill_estimator(struct net_rate_estimator __rcu **rate_est)
+{
+	struct net_rate_estimator *est;
+
+	est = xchg((__force struct net_rate_estimator **)rate_est, NULL);
+	if (est) {
+		timer_shutdown_sync(&est->timer);
+		kfree_rcu(est, rcu);
+	}
+}
+EXPORT_SYMBOL(gen_kill_estimator);
+
+/**
+ * gen_replace_estimator - replace rate estimator configuration
+ * @bstats: basic statistics
+ * @cpu_bstats: bstats per cpu
+ * @rate_est: rate estimator statistics
+ * @lock: lock for statistics and control path
+ * @running: true if @bstats represents a running qdisc, thus @bstats'
+ *           internal values might change during basic reads. Only used
+ *           if @cpu_bstats is NULL
+ * @opt: rate estimator configuration TLV
+ *
+ * Replaces the configuration of a rate estimator by calling
+ * gen_kill_estimator() and gen_new_estimator().
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int gen_replace_estimator(struct gnet_stats_basic_sync *bstats,
+			  struct gnet_stats_basic_sync __percpu *cpu_bstats,
+			  struct net_rate_estimator __rcu **rate_est,
+			  spinlock_t *lock,
+			  bool running, struct nlattr *opt)
+{
+	return gen_new_estimator(bstats, cpu_bstats, rate_est,
+				 lock, running, opt);
+}
+EXPORT_SYMBOL(gen_replace_estimator);
+
+/**
+ * gen_estimator_active - test if estimator is currently in use
+ * @rate_est: rate estimator
+ *
+ * Returns true if estimator is active, and false if not.
+ */
+bool gen_estimator_active(struct net_rate_estimator __rcu **rate_est)
+{
+	return !!rcu_access_pointer(*rate_est);
+}
+EXPORT_SYMBOL(gen_estimator_active);
+
+bool gen_estimator_read(struct net_rate_estimator __rcu **rate_est,
+			struct gnet_stats_rate_est64 *sample)
+{
+	struct net_rate_estimator *est;
+	unsigned seq;
+
+	rcu_read_lock();
+	est = rcu_dereference(*rate_est);
+	if (!est) {
+		rcu_read_unlock();
+		return false;
+	}
+
+	do {
+		seq = read_seqcount_begin(&est->seq);
+		sample->bps = est->avbps >> 8;
+		sample->pps = est->avpps >> 8;
+	} while (read_seqcount_retry(&est->seq, seq));
+
+	rcu_read_unlock();
+	return true;
+}
+EXPORT_SYMBOL(gen_estimator_read);