[mirror_ubuntu-hirsute-kernel.git] / net / dccp / ccids / lib / tfrc.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef _TFRC_H_
#define _TFRC_H_
/*
 *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
 *  Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
 *  Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
 *  Copyright (c) 2005   Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *  Copyright (c) 2003   Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
 */
#include <linux/types.h>
#include <linux/math64.h>
#include "../../dccp.h"

/* internal includes that this library exports: */
#include "loss_interval.h"
#include "packet_history.h"

#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
extern bool tfrc_debug;
#define tfrc_pr_debug(format, a...)	DCCP_PR_DEBUG(tfrc_debug, format, ##a)
#else
#define tfrc_pr_debug(format, a...)
#endif

/* integer-arithmetic divisions of type (a * 1000000)/b */
static inline u64 scaled_div(u64 a, u64 b)
{
	BUG_ON(b == 0);
	return div64_u64(a * 1000000, b);
}

static inline u32 scaled_div32(u64 a, u64 b)
{
	u64 result = scaled_div(a, b);

	if (result > UINT_MAX) {
		DCCP_CRIT("Overflow: %llu/%llu > UINT_MAX",
			  (unsigned long long)a, (unsigned long long)b);
		return UINT_MAX;
	}
	return result;
}

/**
 * tfrc_ewma  -  Exponentially weighted moving average
 * @weight: Weight to be used as damping factor, in units of 1/10
 */
static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight)
{
	return avg ? (weight * avg + (10 - weight) * newval) / 10 : newval;
}

u32 tfrc_calc_x(u16 s, u32 R, u32 p);
u32 tfrc_calc_x_reverse_lookup(u32 fvalue);
u32 tfrc_invert_loss_event_rate(u32 loss_event_rate);

int tfrc_tx_packet_history_init(void);
void tfrc_tx_packet_history_exit(void);
int tfrc_rx_packet_history_init(void);
void tfrc_rx_packet_history_exit(void);

int tfrc_li_init(void);
void tfrc_li_exit(void);

#ifdef CONFIG_IP_DCCP_TFRC_LIB
int tfrc_lib_init(void);
void tfrc_lib_exit(void);
#else
#define tfrc_lib_init() (0)
#define tfrc_lib_exit()
#endif
#endif /* _TFRC_H_ */
Commit	Line	Data
2874c5fd	1	/* SPDX-License-Identifier: GPL-2.0-or-later */
36729c1a ACM	2	#ifndef _TFRC_H_
	3	#define _TFRC_H_
	4	/*
c40616c5 GR	5	* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
	6	* Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
	7	* Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
	8	* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
	9	* Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
36729c1a	10	*/
36729c1a	11	#include <linux/types.h>
7deb0f85	12	#include <linux/math64.h>
c40616c5	13	#include "../../dccp.h"
129fa447 GR	14
129fa447 GR	15	/* internal includes that this library exports: */
8a9c7e92 GR	16	#include "loss_interval.h"
8a9c7e92 GR	17	#include "packet_history.h"
c40616c5 GR	18
c40616c5 GR	19	#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
09db3080	20	extern bool tfrc_debug;
c40616c5 GR	21	#define tfrc_pr_debug(format, a...) DCCP_PR_DEBUG(tfrc_debug, format, ##a)
	22	#else
	23	#define tfrc_pr_debug(format, a...)
	24	#endif
d63d8364 GR	25
d63d8364 GR	26	/* integer-arithmetic divisions of type (a * 1000000)/b */
7deb0f85	27	static inline u64 scaled_div(u64 a, u64 b)
d63d8364	28	{
aa1b1ff0	29	BUG_ON(b == 0);
7deb0f85	30	return div64_u64(a * 1000000, b);
d63d8364 GR	31	}
d63d8364 GR	32
7deb0f85	33	static inline u32 scaled_div32(u64 a, u64 b)
d63d8364 GR	34	{
	35	u64 result = scaled_div(a, b);
	36
	37	if (result > UINT_MAX) {
7deb0f85 GR	38	DCCP_CRIT("Overflow: %llu/%llu > UINT_MAX",
7deb0f85 GR	39	(unsigned long long)a, (unsigned long long)b);
d63d8364 GR	40	return UINT_MAX;
	41	}
	42	return result;
	43	}
36729c1a	44
c3ada46a GR	45	/**
	46	* tfrc_ewma - Exponentially weighted moving average
	47	* @weight: Weight to be used as damping factor, in units of 1/10
	48	*/
	49	static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight)
	50	{
	51	return avg ? (weight * avg + (10 - weight) * newval) / 10 : newval;
	52	}
	53
a402a5aa JP	54	u32 tfrc_calc_x(u16 s, u32 R, u32 p);
	55	u32 tfrc_calc_x_reverse_lookup(u32 fvalue);
	56	u32 tfrc_invert_loss_event_rate(u32 loss_event_rate);
36729c1a	57
a402a5aa JP	58	int tfrc_tx_packet_history_init(void);
	59	void tfrc_tx_packet_history_exit(void);
	60	int tfrc_rx_packet_history_init(void);
	61	void tfrc_rx_packet_history_exit(void);
1e2f0e5e	62
a402a5aa JP	63	int tfrc_li_init(void);
a402a5aa JP	64	void tfrc_li_exit(void);
129fa447 GR	65
129fa447 GR	66	#ifdef CONFIG_IP_DCCP_TFRC_LIB
a402a5aa JP	67	int tfrc_lib_init(void);
a402a5aa JP	68	void tfrc_lib_exit(void);
129fa447 GR	69	#else
	70	#define tfrc_lib_init() (0)
	71	#define tfrc_lib_exit()
	72	#endif
36729c1a	73	#endif /* _TFRC_H_ */