LXR linux/net/dccp/ccids/lib/tfrc.h

   1#ifndef _TFRC_H_
   2#define _TFRC_H_
   3/*
   4 *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
   5 *  Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
   6 *  Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
   7 *  Copyright (c) 2005   Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   8 *  Copyright (c) 2003   Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
   9 *
  10 *  This program is free software; you can redistribute it and/or modify
  11 *  it under the terms of the GNU General Public License as published by
  12 *  the Free Software Foundation; either version 2 of the License, or
  13 *  (at your option) any later version.
  14 */
  15#include <linux/types.h>
  16#include <linux/math64.h>
  17#include "../../dccp.h"
  18
  19/* internal includes that this library exports: */
  20#include "loss_interval.h"
  21#include "packet_history.h"
  22
  23#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
  24extern bool tfrc_debug;
  25#define tfrc_pr_debug(format, a...)     DCCP_PR_DEBUG(tfrc_debug, format, ##a)
  26#else
  27#define tfrc_pr_debug(format, a...)
  28#endif
  29
  30/* integer-arithmetic divisions of type (a * 1000000)/b */
  31static inline u64 scaled_div(u64 a, u64 b)
  32{
  33        BUG_ON(b == 0);
  34        return div64_u64(a * 1000000, b);
  35}
  36
  37static inline u32 scaled_div32(u64 a, u64 b)
  38{
  39        u64 result = scaled_div(a, b);
  40
  41        if (result > UINT_MAX) {
  42                DCCP_CRIT("Overflow: %llu/%llu > UINT_MAX",
  43                          (unsigned long long)a, (unsigned long long)b);
  44                return UINT_MAX;
  45        }
  46        return result;
  47}
  48
  49/**
  50 * tfrc_ewma  -  Exponentially weighted moving average
  51 * @weight: Weight to be used as damping factor, in units of 1/10
  52 */
  53static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight)
  54{
  55        return avg ? (weight * avg + (10 - weight) * newval) / 10 : newval;
  56}
  57
  58extern u32  tfrc_calc_x(u16 s, u32 R, u32 p);
  59extern u32  tfrc_calc_x_reverse_lookup(u32 fvalue);
  60extern u32  tfrc_invert_loss_event_rate(u32 loss_event_rate);
  61
  62extern int  tfrc_tx_packet_history_init(void);
  63extern void tfrc_tx_packet_history_exit(void);
  64extern int  tfrc_rx_packet_history_init(void);
  65extern void tfrc_rx_packet_history_exit(void);
  66
  67extern int  tfrc_li_init(void);
  68extern void tfrc_li_exit(void);
  69
  70#ifdef CONFIG_IP_DCCP_TFRC_LIB
  71extern int  tfrc_lib_init(void);
  72extern void tfrc_lib_exit(void);
  73#else
  74#define tfrc_lib_init() (0)
  75#define tfrc_lib_exit()
  76#endif
  77#endif /* _TFRC_H_ */
  78