src/openvpn/shaper.h

   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) 2002-2024 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 {
  49     int bytes_per_second;
  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
  74 shaper_reset(struct shaper *s, int bytes_per_second)
  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
  86 shaper_init(struct shaper *s, int bytes_per_second)
  87 {
  88     shaper_reset(s, bytes_per_second);
  89     shaper_reset_wakeup(s);
  90 }
  91
  92 static inline int
  93 shaper_current_bandwidth(struct shaper *s)
  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
 103 shaper_delay(struct shaper *s)
 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);
 168     ASSERT(s->bytes_per_second);
 169     shaper_reset(s, new_bandwidth);
 170     return s->bytes_per_second != orig_bandwidth;
 171 }
 172 #endif
 173
 174 #endif /* ifndef SHAPER_H */