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 <asm/div64.h> 19 #include "../../dccp.h" 20 /* internal includes that this module exports: */ 21 #include "loss_interval.h" 22 #include "packet_history.h" 23 24 #ifdef CONFIG_IP_DCCP_TFRC_DEBUG 25 extern int tfrc_debug; 26 #define tfrc_pr_debug(format, a...) DCCP_PR_DEBUG(tfrc_debug, format, ##a) 27 #else 28 #define tfrc_pr_debug(format, a...) 29 #endif 30 31 /* integer-arithmetic divisions of type (a * 1000000)/b */ 32 static inline u64 scaled_div(u64 a, u32 b) 33 { 34 BUG_ON(b==0); 35 a *= 1000000; 36 do_div(a, b); 37 return a; 38 } 39 40 static inline u32 scaled_div32(u64 a, u32 b) 41 { 42 u64 result = scaled_div(a, b); 43 44 if (result > UINT_MAX) { 45 DCCP_CRIT("Overflow: a(%llu)/b(%u) > ~0U", 46 (unsigned long long)a, b); 47 return UINT_MAX; 48 } 49 return result; 50 } 51 52 /** 53 * tfrc_ewma - Exponentially weighted moving average 54 * @weight: Weight to be used as damping factor, in units of 1/10 55 */ 56 static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight) 57 { 58 return avg ? (weight * avg + (10 - weight) * newval) / 10 : newval; 59 } 60 61 extern u32 tfrc_calc_x(u16 s, u32 R, u32 p); 62 extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue); 63 64 #endif /* _TFRC_H_ */ 65