1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 #ifndef _TFRC_H_ 3 #define _TFRC_H_ 4 /* 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 10 */ 11 #include <linux/types.h> 12 #include <linux/math64.h> 13 #include "../../dccp.h" 14 15 /* internal includes that this library exports: */ 16 #include "loss_interval.h" 17 #include "packet_history.h" 18 19 #ifdef CONFIG_IP_DCCP_TFRC_DEBUG 20 extern bool tfrc_debug; 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 25 26 /* integer-arithmetic divisions of type (a * 1000000)/b */ 27 static inline u64 scaled_div(u64 a, u64 b) 28 { 29 BUG_ON(b == 0); 30 return div64_u64(a * 1000000, b); 31 } 32 33 static inline u32 scaled_div32(u64 a, u64 b) 34 { 35 u64 result = scaled_div(a, b); 36 37 if (result > UINT_MAX) { 38 DCCP_CRIT("Overflow: %llu/%llu > UINT_MAX", 39 (unsigned long long)a, (unsigned long long)b); 40 return UINT_MAX; 41 } 42 return result; 43 } 44 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 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); 57 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); 62 63 int tfrc_li_init(void); 64 void tfrc_li_exit(void); 65 66 #ifdef CONFIG_IP_DCCP_TFRC_LIB 67 int tfrc_lib_init(void); 68 void tfrc_lib_exit(void); 69 #else 70 #define tfrc_lib_init() (0) 71 #define tfrc_lib_exit() 72 #endif 73 #endif /* _TFRC_H_ */ 74