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
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