/*
   * net/core/gen_stats.c
   *
   *             This program is free software; you can redistribute it and/or
   *             modify it under the terms of the GNU General Public License
   *             as published by the Free Software Foundation; either version
   *             2 of the License, or (at your option) any later version.
   *
   * Authors:  Thomas Graf <tgraf@suug.ch>
   *           Jamal Hadi Salim
   *           Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   *
   * See Documentation/networking/gen_stats.txt
   */
  
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/interrupt.h>
  #include <linux/socket.h>
  #include <linux/rtnetlink.h>
  #include <linux/gen_stats.h>

  #include <net/netlink.h>

  #include <net/gen_stats.h>
  
  
  static inline int
  gnet_stats_copy(struct gnet_dump *d, int type, void *buf, int size)
  {

  	if (nla_put(d->skb, type, size, buf))
  		goto nla_put_failure;

  	return 0;

  nla_put_failure:

  	spin_unlock_bh(d->lock);
  	return -1;
  }
  
  /**
   * gnet_stats_start_copy_compat - start dumping procedure in compatibility mode
   * @skb: socket buffer to put statistics TLVs into
   * @type: TLV type for top level statistic TLV
   * @tc_stats_type: TLV type for backward compatibility struct tc_stats TLV
   * @xstats_type: TLV type for backward compatibility xstats TLV
   * @lock: statistics lock
   * @d: dumping handle
   *
   * Initializes the dumping handle, grabs the statistic lock and appends
   * an empty TLV header to the socket buffer for use a container for all
   * other statistic TLVS.
   *
   * The dumping handle is marked to be in backward compatibility mode telling
   * all gnet_stats_copy_XXX() functions to fill a local copy of struct tc_stats.
   *
   * Returns 0 on success or -1 if the room in the socket buffer was not sufficient.
   */
  int
  gnet_stats_start_copy_compat(struct sk_buff *skb, int type, int tc_stats_type,
  	int xstats_type, spinlock_t *lock, struct gnet_dump *d)

  	__acquires(lock)

  {
  	memset(d, 0, sizeof(*d));

  	spin_lock_bh(lock);
  	d->lock = lock;
  	if (type)

  		d->tail = (struct nlattr *)skb_tail_pointer(skb);

  	d->skb = skb;
  	d->compat_tc_stats = tc_stats_type;
  	d->compat_xstats = xstats_type;
  
  	if (d->tail)
  		return gnet_stats_copy(d, type, NULL, 0);
  
  	return 0;
  }

  EXPORT_SYMBOL(gnet_stats_start_copy_compat);

  
  /**
   * gnet_stats_start_copy_compat - start dumping procedure in compatibility mode
   * @skb: socket buffer to put statistics TLVs into
   * @type: TLV type for top level statistic TLV
   * @lock: statistics lock
   * @d: dumping handle
   *
   * Initializes the dumping handle, grabs the statistic lock and appends
   * an empty TLV header to the socket buffer for use a container for all
   * other statistic TLVS.
   *
   * Returns 0 on success or -1 if the room in the socket buffer was not sufficient.
   */
  int
  gnet_stats_start_copy(struct sk_buff *skb, int type, spinlock_t *lock,
  	struct gnet_dump *d)
  {
  	return gnet_stats_start_copy_compat(skb, type, 0, 0, lock, d);
  }

  EXPORT_SYMBOL(gnet_stats_start_copy);

  static void
  __gnet_stats_copy_basic_cpu(struct gnet_stats_basic_packed *bstats,
  			    struct gnet_stats_basic_cpu __percpu *cpu)
  {
  	int i;
  
  	for_each_possible_cpu(i) {
  		struct gnet_stats_basic_cpu *bcpu = per_cpu_ptr(cpu, i);
  		unsigned int start;

  		u64 bytes;
  		u32 packets;

  
  		do {
  			start = u64_stats_fetch_begin_irq(&bcpu->syncp);
  			bytes = bcpu->bstats.bytes;
  			packets = bcpu->bstats.packets;
  		} while (u64_stats_fetch_retry_irq(&bcpu->syncp, start));

  		bstats->bytes += bytes;
  		bstats->packets += packets;

  	}
  }
  
  void
  __gnet_stats_copy_basic(struct gnet_stats_basic_packed *bstats,
  			struct gnet_stats_basic_cpu __percpu *cpu,
  			struct gnet_stats_basic_packed *b)
  {
  	if (cpu) {
  		__gnet_stats_copy_basic_cpu(bstats, cpu);
  	} else {
  		bstats->bytes = b->bytes;
  		bstats->packets = b->packets;
  	}
  }
  EXPORT_SYMBOL(__gnet_stats_copy_basic);

  /**
   * gnet_stats_copy_basic - copy basic statistics into statistic TLV
   * @d: dumping handle
   * @b: basic statistics
   *
   * Appends the basic statistics to the top level TLV created by
   * gnet_stats_start_copy().
   *
   * Returns 0 on success or -1 with the statistic lock released
   * if the room in the socket buffer was not sufficient.
   */
  int

  gnet_stats_copy_basic(struct gnet_dump *d,
  		      struct gnet_stats_basic_cpu __percpu *cpu,
  		      struct gnet_stats_basic_packed *b)

  {

  	struct gnet_stats_basic_packed bstats = {0};
  
  	__gnet_stats_copy_basic(&bstats, cpu, b);

  	if (d->compat_tc_stats) {

  		d->tc_stats.bytes = bstats.bytes;
  		d->tc_stats.packets = bstats.packets;

  	}

  	if (d->tail) {
  		struct gnet_stats_basic sb;

  		memset(&sb, 0, sizeof(sb));

  		sb.bytes = bstats.bytes;
  		sb.packets = bstats.packets;

  		return gnet_stats_copy(d, TCA_STATS_BASIC, &sb, sizeof(sb));
  	}

  	return 0;
  }

  EXPORT_SYMBOL(gnet_stats_copy_basic);

  
  /**
   * gnet_stats_copy_rate_est - copy rate estimator statistics into statistics TLV
   * @d: dumping handle

   * @b: basic statistics

   * @r: rate estimator statistics
   *
   * Appends the rate estimator statistics to the top level TLV created by
   * gnet_stats_start_copy().
   *
   * Returns 0 on success or -1 with the statistic lock released
   * if the room in the socket buffer was not sufficient.
   */
  int

  gnet_stats_copy_rate_est(struct gnet_dump *d,
  			 const struct gnet_stats_basic_packed *b,

  			 struct gnet_stats_rate_est64 *r)

  {

  	struct gnet_stats_rate_est est;
  	int res;

  	if (b && !gen_estimator_active(b, r))
  		return 0;

  	est.bps = min_t(u64, UINT_MAX, r->bps);
  	/* we have some time before reaching 2^32 packets per second */
  	est.pps = r->pps;

  	if (d->compat_tc_stats) {

  		d->tc_stats.bps = est.bps;
  		d->tc_stats.pps = est.pps;

  	}

  	if (d->tail) {
  		res = gnet_stats_copy(d, TCA_STATS_RATE_EST, &est, sizeof(est));
  		if (res < 0 || est.bps == r->bps)
  			return res;
  		/* emit 64bit stats only if needed */
  		return gnet_stats_copy(d, TCA_STATS_RATE_EST64, r, sizeof(*r));
  	}

  
  	return 0;
  }

  EXPORT_SYMBOL(gnet_stats_copy_rate_est);

  static void
  __gnet_stats_copy_queue_cpu(struct gnet_stats_queue *qstats,
  			    const struct gnet_stats_queue __percpu *q)
  {
  	int i;
  
  	for_each_possible_cpu(i) {
  		const struct gnet_stats_queue *qcpu = per_cpu_ptr(q, i);
  
  		qstats->qlen = 0;
  		qstats->backlog += qcpu->backlog;
  		qstats->drops += qcpu->drops;
  		qstats->requeues += qcpu->requeues;
  		qstats->overlimits += qcpu->overlimits;
  	}
  }
  
  static void __gnet_stats_copy_queue(struct gnet_stats_queue *qstats,
  				    const struct gnet_stats_queue __percpu *cpu,
  				    const struct gnet_stats_queue *q,
  				    __u32 qlen)
  {
  	if (cpu) {
  		__gnet_stats_copy_queue_cpu(qstats, cpu);
  	} else {
  		qstats->qlen = q->qlen;
  		qstats->backlog = q->backlog;
  		qstats->drops = q->drops;
  		qstats->requeues = q->requeues;
  		qstats->overlimits = q->overlimits;
  	}
  
  	qstats->qlen = qlen;
  }

  /**
   * gnet_stats_copy_queue - copy queue statistics into statistics TLV
   * @d: dumping handle

   * @cpu_q: per cpu queue statistics

   * @q: queue statistics

   * @qlen: queue length statistics

   *
   * Appends the queue statistics to the top level TLV created by

   * gnet_stats_start_copy(). Using per cpu queue statistics if
   * they are available.

   *
   * Returns 0 on success or -1 with the statistic lock released
   * if the room in the socket buffer was not sufficient.
   */
  int

  gnet_stats_copy_queue(struct gnet_dump *d,

  		      struct gnet_stats_queue __percpu *cpu_q,

  		      struct gnet_stats_queue *q, __u32 qlen)

  {

  	struct gnet_stats_queue qstats = {0};
  
  	__gnet_stats_copy_queue(&qstats, cpu_q, q, qlen);

  	if (d->compat_tc_stats) {

  		d->tc_stats.drops = qstats.drops;
  		d->tc_stats.qlen = qstats.qlen;
  		d->tc_stats.backlog = qstats.backlog;
  		d->tc_stats.overlimits = qstats.overlimits;

  	}
  
  	if (d->tail)

  		return gnet_stats_copy(d, TCA_STATS_QUEUE,
  				       &qstats, sizeof(qstats));

  
  	return 0;
  }

  EXPORT_SYMBOL(gnet_stats_copy_queue);

  
  /**
   * gnet_stats_copy_app - copy application specific statistics into statistics TLV
   * @d: dumping handle
   * @st: application specific statistics data
   * @len: length of data
   *

   * Appends the application specific statistics to the top level TLV created by

   * gnet_stats_start_copy() and remembers the data for XSTATS if the dumping
   * handle is in backward compatibility mode.
   *
   * Returns 0 on success or -1 with the statistic lock released
   * if the room in the socket buffer was not sufficient.
   */
  int
  gnet_stats_copy_app(struct gnet_dump *d, void *st, int len)
  {
  	if (d->compat_xstats) {
  		d->xstats = st;
  		d->xstats_len = len;
  	}
  
  	if (d->tail)
  		return gnet_stats_copy(d, TCA_STATS_APP, st, len);
  
  	return 0;
  }

  EXPORT_SYMBOL(gnet_stats_copy_app);

  
  /**
   * gnet_stats_finish_copy - finish dumping procedure
   * @d: dumping handle
   *
   * Corrects the length of the top level TLV to include all TLVs added
   * by gnet_stats_copy_XXX() calls. Adds the backward compatibility TLVs
   * if gnet_stats_start_copy_compat() was used and releases the statistics
   * lock.
   *
   * Returns 0 on success or -1 with the statistic lock released
   * if the room in the socket buffer was not sufficient.
   */
  int
  gnet_stats_finish_copy(struct gnet_dump *d)
  {
  	if (d->tail)

  		d->tail->nla_len = skb_tail_pointer(d->skb) - (u8 *)d->tail;

  
  	if (d->compat_tc_stats)
  		if (gnet_stats_copy(d, d->compat_tc_stats, &d->tc_stats,
  			sizeof(d->tc_stats)) < 0)
  			return -1;
  
  	if (d->compat_xstats && d->xstats) {
  		if (gnet_stats_copy(d, d->compat_xstats, d->xstats,
  			d->xstats_len) < 0)
  			return -1;
  	}
  
  	spin_unlock_bh(d->lock);
  	return 0;
  }

  EXPORT_SYMBOL(gnet_stats_finish_copy);