net/dccp/ccids/lib/tfrc.h

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