OpenVPN
shaper.h
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1 /*
2  * OpenVPN -- An application to securely tunnel IP networks
3  * over a single UDP port, with support for SSL/TLS-based
4  * session authentication and key exchange,
5  * packet encryption, packet authentication, and
6  * packet compression.
7  *
8  * Copyright (C) 2002-2021 OpenVPN Inc <sales@openvpn.net>
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 version 2
12  * as published by the Free Software Foundation.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License along
20  * with this program; if not, write to the Free Software Foundation, Inc.,
21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22  */
23 
24 #ifndef SHAPER_H
25 #define SHAPER_H
26 
27 /*#define SHAPER_DEBUG*/
28 
29 #include "basic.h"
30 #include "integer.h"
31 #include "misc.h"
32 #include "error.h"
33 #include "interval.h"
34 
35 /*
36  * A simple traffic shaper for
37  * the output direction.
38  */
39 
40 #define SHAPER_MIN 100 /* bytes per second */
41 #define SHAPER_MAX 100000000
42 
43 #define SHAPER_MAX_TIMEOUT 10 /* seconds */
44 
45 #define SHAPER_USE_FP
46 
47 struct shaper
48 {
50  struct timeval wakeup;
51 
52 #ifdef SHAPER_USE_FP
53  double factor;
54 #else
55  int factor;
56 #endif
57 };
58 
59 void shaper_msg(struct shaper *s);
60 
61 void shaper_reset_wakeup(struct shaper *s);
62 
63 /*
64  * We want to wake up in delay microseconds. If timeval is larger
65  * than delay, set timeval to delay.
66  */
67 bool shaper_soonest_event(struct timeval *tv, int delay);
68 
69 /*
70  * inline functions
71  */
72 
73 static inline void
75 {
76  s->bytes_per_second = constrain_int(bytes_per_second, SHAPER_MIN, SHAPER_MAX);
77 
78 #ifdef SHAPER_USE_FP
79  s->factor = 1000000.0 / (double)s->bytes_per_second;
80 #else
81  s->factor = 1000000 / s->bytes_per_second;
82 #endif
83 }
84 
85 static inline void
87 {
88  shaper_reset(s, bytes_per_second);
90 }
91 
92 static inline int
94 {
95  return s->bytes_per_second;
96 }
97 
98 /*
99  * Returns traffic shaping delay in microseconds relative to current
100  * time, or 0 if no delay.
101  */
102 static inline int
104 {
105  struct timeval tv;
106  int delay = 0;
107 
108  if (tv_defined(&s->wakeup))
109  {
110  ASSERT(!openvpn_gettimeofday(&tv, NULL));
111  delay = tv_subtract(&s->wakeup, &tv, SHAPER_MAX_TIMEOUT);
112 #ifdef SHAPER_DEBUG
113  dmsg(D_SHAPER_DEBUG, "SHAPER shaper_delay delay=%d", delay);
114 #endif
115  }
116 
117  return delay > 0 ? delay : 0;
118 }
119 
120 
121 /*
122  * We are about to send a datagram of nbytes bytes.
123  *
124  * Compute when we can send another datagram,
125  * based on target throughput (s->bytes_per_second).
126  */
127 static inline void
128 shaper_wrote_bytes(struct shaper *s, int nbytes)
129 {
130  struct timeval tv;
131 
132  /* compute delay in microseconds */
133  tv.tv_sec = 0;
134 #ifdef SHAPER_USE_FP
135  tv.tv_usec = min_int((int)((double)max_int(nbytes, 100) * s->factor), (SHAPER_MAX_TIMEOUT*1000000));
136 #else
137  tv.tv_usec = s->bytes_per_second
138  ? min_int(max_int(nbytes, 100) * s->factor, (SHAPER_MAX_TIMEOUT*1000000))
139  : 0;
140 #endif
141 
142  if (tv.tv_usec)
143  {
144  ASSERT(!openvpn_gettimeofday(&s->wakeup, NULL));
145  tv_add(&s->wakeup, &tv);
146 
147 #ifdef SHAPER_DEBUG
148  dmsg(D_SHAPER_DEBUG, "SHAPER shaper_wrote_bytes bytes=%d delay=%ld sec=%" PRIi64 " usec=%ld",
149  nbytes,
150  (long)tv.tv_usec,
151  (int64_t)s->wakeup.tv_sec,
152  (long)s->wakeup.tv_usec);
153 #endif
154  }
155 }
156 
157 #if 0
158 /*
159  * Increase/Decrease bandwidth by a percentage.
160  *
161  * Return true if bandwidth changed.
162  */
163 static inline bool
164 shaper_change_pct(struct shaper *s, int pct)
165 {
166  const int orig_bandwidth = s->bytes_per_second;
167  const int new_bandwidth = orig_bandwidth + (orig_bandwidth * pct / 100);
169  shaper_reset(s, new_bandwidth);
170  return s->bytes_per_second != orig_bandwidth;
171 }
172 #endif
173 
174 #endif /* ifndef SHAPER_H */
static int tv_subtract(const struct timeval *tv1, const struct timeval *tv2, const unsigned int max_seconds)
Definition: otime.h:115
#define dmsg(flags,...)
Definition: error.h:157
static void shaper_init(struct shaper *s, int bytes_per_second)
Definition: shaper.h:86
double factor
Definition: shaper.h:53
#define ASSERT(x)
Definition: error.h:204
#define D_SHAPER_DEBUG
Definition: errlevel.h:170
static void shaper_reset(struct shaper *s, int bytes_per_second)
Definition: shaper.h:74
Definition: shaper.h:47
static bool tv_defined(const struct timeval *tv)
Definition: otime.h:108
static void tv_add(struct timeval *dest, const struct timeval *src)
Definition: otime.h:132
static int shaper_delay(struct shaper *s)
Definition: shaper.h:103
static int openvpn_gettimeofday(struct timeval *tv, void *tz)
Definition: otime.h:64
static int max_int(int x, int y)
Definition: integer.h:69
bool shaper_soonest_event(struct timeval *tv, int delay)
Definition: shaper.c:39
#define SHAPER_MIN
Definition: shaper.h:40
static void shaper_wrote_bytes(struct shaper *s, int nbytes)
Definition: shaper.h:128
#define SHAPER_MAX_TIMEOUT
Definition: shaper.h:43
struct timeval wakeup
Definition: shaper.h:50
static int constrain_int(int x, int min, int max)
Definition: integer.h:95
static int min_int(int x, int y)
Definition: integer.h:82
static int shaper_current_bandwidth(struct shaper *s)
Definition: shaper.h:93
int bytes_per_second
Definition: shaper.h:49
void shaper_msg(struct shaper *s)
Definition: shaper.c:90
void shaper_reset_wakeup(struct shaper *s)
Definition: shaper.c:84
#define SHAPER_MAX
Definition: shaper.h:41