linux/include/net/pie.h

/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef __NET_SCHED_PIE_H
#define __NET_SCHED_PIE_H

#include <linux/ktime.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <net/inet_ecn.h>
#include <net/pkt_sched.h>

#define MAX_PROB …
#define DTIME_INVALID …
#define QUEUE_THRESHOLD …
#define DQCOUNT_INVALID …
#define PIE_SCALE …

/**
 * struct pie_params - contains pie parameters
 * @target:		target delay in pschedtime
 * @tupdate:		interval at which drop probability is calculated
 * @limit:		total number of packets that can be in the queue
 * @alpha:		parameter to control drop probability
 * @beta:		parameter to control drop probability
 * @ecn:		is ECN marking of packets enabled
 * @bytemode:		is drop probability scaled based on pkt size
 * @dq_rate_estimator:	is Little's law used for qdelay calculation
 */
struct pie_params { … };

/**
 * struct pie_vars - contains pie variables
 * @qdelay:		current queue delay
 * @qdelay_old:		queue delay in previous qdelay calculation
 * @burst_time:		burst time allowance
 * @dq_tstamp:		timestamp at which dq rate was last calculated
 * @prob:		drop probability
 * @accu_prob:		accumulated drop probability
 * @dq_count:		number of bytes dequeued in a measurement cycle
 * @avg_dq_rate:	calculated average dq rate
 * @backlog_old:	queue backlog during previous qdelay calculation
 */
struct pie_vars { … };

/**
 * struct pie_stats - contains pie stats
 * @packets_in:	total number of packets enqueued
 * @dropped:	packets dropped due to pie action
 * @overlimit:	packets dropped due to lack of space in queue
 * @ecn_mark:	packets marked with ECN
 * @maxq:	maximum queue size
 */
struct pie_stats { … };

/**
 * struct pie_skb_cb - contains private skb vars
 * @enqueue_time:	timestamp when the packet is enqueued
 * @mem_usage:		size of the skb during enqueue
 */
struct pie_skb_cb { … };

static inline void pie_params_init(struct pie_params *params)
{ … }

static inline void pie_vars_init(struct pie_vars *vars)
{ … }

static inline struct pie_skb_cb *get_pie_cb(const struct sk_buff *skb)
{ … }

static inline psched_time_t pie_get_enqueue_time(const struct sk_buff *skb)
{ … }

static inline void pie_set_enqueue_time(struct sk_buff *skb)
{ … }

bool pie_drop_early(struct Qdisc *sch, struct pie_params *params,
		    struct pie_vars *vars, u32 backlog, u32 packet_size);

void pie_process_dequeue(struct sk_buff *skb, struct pie_params *params,
			 struct pie_vars *vars, u32 backlog);

void pie_calculate_probability(struct pie_params *params, struct pie_vars *vars,
			       u32 backlog);

#endif