release/src/router/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) 2002-2009 OpenVPN Technologies, 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
  20  *  along with this program (see the file COPYING included with this
  21  *  distribution); if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #ifndef SHAPER_H
  26 #define SHAPER_H
  27
  28 /*#define SHAPER_DEBUG*/
  29
  30 #ifdef HAVE_GETTIMEOFDAY
  31
  32 #include "basic.h"
  33 #include "integer.h"
  34 #include "misc.h"
  35 #include "error.h"
  36 #include "interval.h"
  37
  38 /*
  39  * A simple traffic shaper for
  40  * the output direction.
  41  */
  42
  43 #define SHAPER_MIN 100          /* bytes per second */
  44 #define SHAPER_MAX 100000000
  45
  46 #define SHAPER_MAX_TIMEOUT 10   /* seconds */
  47
  48 #define SHAPER_USE_FP
  49
  50 struct shaper
  51 {
  52   int bytes_per_second;
  53   struct timeval wakeup;
  54
  55 #ifdef SHAPER_USE_FP
  56   double factor;
  57 #else
  58   int factor;
  59 #endif
  60 };
  61
  62 void shaper_msg (struct shaper *s);
  63 void shaper_reset_wakeup (struct shaper *s);
  64
  65 /*
  66  * We want to wake up in delay microseconds.  If timeval is larger
  67  * than delay, set timeval to delay.
  68  */
  69 bool shaper_soonest_event (struct timeval *tv, int delay);
  70
  71 /*
  72  * inline functions
  73  */
  74
  75 static inline void
  76 shaper_reset (struct shaper *s, int bytes_per_second)
  77 {
  78   s->bytes_per_second = bytes_per_second ? constrain_int (bytes_per_second, SHAPER_MIN, SHAPER_MAX) : 0;
  79
  80 #ifdef SHAPER_USE_FP
  81   s->factor = 1000000.0 / (double)s->bytes_per_second;
  82 #else
  83   s->factor = 1000000 / s->bytes_per_second;
  84 #endif
  85 }
  86
  87 static inline void
  88 shaper_init (struct shaper *s, int bytes_per_second)
  89 {
  90   shaper_reset (s, bytes_per_second);
  91   shaper_reset_wakeup (s);
  92 }
  93
  94 static inline int
  95 shaper_current_bandwidth (struct shaper *s)
  96 {
  97   return s->bytes_per_second;
  98 }
  99
 100 /*
 101  * Returns traffic shaping delay in microseconds relative to current
 102  * time, or 0 if no delay.
 103  */
 104 static inline int
 105 shaper_delay (struct shaper* s)
 106 {
 107   struct timeval tv;
 108   int delay = 0;
 109
 110   if (tv_defined (&s->wakeup))
 111     {
 112       ASSERT (!openvpn_gettimeofday (&tv, NULL));
 113       delay = tv_subtract (&s->wakeup, &tv, SHAPER_MAX_TIMEOUT);
 114 #ifdef SHAPER_DEBUG
 115       dmsg (D_SHAPER_DEBUG, "SHAPER shaper_delay delay=%d", delay);
 116 #endif
 117     }
 118
 119   return delay > 0 ? delay : 0;
 120 }
 121
 122
 123 /*
 124  * We are about to send a datagram of nbytes bytes.
 125  *
 126  * Compute when we can send another datagram,
 127  * based on target throughput (s->bytes_per_second).
 128  */
 129 static inline void
 130 shaper_wrote_bytes (struct shaper* s, int nbytes)
 131 {
 132   struct timeval tv;
 133
 134   /* compute delay in microseconds */
 135   tv.tv_sec = 0;
 136 #ifdef SHAPER_USE_FP
 137   tv.tv_usec = min_int ((int)((double)max_int (nbytes, 100) * s->factor), (SHAPER_MAX_TIMEOUT*1000000));
 138 #else
 139   tv.tv_usec = s->bytes_per_second
 140     ? min_int (max_int (nbytes, 100) * s->factor, (SHAPER_MAX_TIMEOUT*1000000))
 141     : 0;
 142 #endif
 143
 144   if (tv.tv_usec)
 145     {
 146       ASSERT (!openvpn_gettimeofday (&s->wakeup, NULL));
 147       tv_add (&s->wakeup, &tv);
 148
 149 #ifdef SHAPER_DEBUG
 150       dmsg (D_SHAPER_DEBUG, "SHAPER shaper_wrote_bytes bytes=%d delay=%d sec=%d usec=%d",
 151            nbytes,
 152            (int)tv.tv_usec,
 153            (int)s->wakeup.tv_sec,
 154            (int)s->wakeup.tv_usec);
 155 #endif
 156     }
 157 }
 158
 159 #if 0
 160 /*
 161  * Increase/Decrease bandwidth by a percentage.
 162  *
 163  * Return true if bandwidth changed.
 164  */
 165 static inline bool
 166 shaper_change_pct (struct shaper *s, int pct)
 167 {
 168   const int orig_bandwidth = s->bytes_per_second;
 169   const int new_bandwidth = orig_bandwidth + (orig_bandwidth * pct / 100);
 170   ASSERT (s->bytes_per_second);
 171   shaper_reset (s, new_bandwidth);
 172   return s->bytes_per_second != orig_bandwidth;
 173 }
 174 #endif
 175
 176 #endif /* HAVE_GETTIMEOFDAY */
 177
 178 #endif