stun/usages/timer.c

   1 /*
   2  * This file is part of the Nice GLib ICE library.
   3  *
   4  * (C) 2008-2009 Collabora Ltd.
   5  *  Contact: Youness Alaoui
   6  * (C) 2007-2009 Nokia Corporation. All rights reserved.
   7  *  Contact: Rémi Denis-Courmont
   8  *
   9  * The contents of this file are subject to the Mozilla Public License Version
  10  * 1.1 (the "License"); you may not use this file except in compliance with
  11  * the License. You may obtain a copy of the License at
  12  * http://www.mozilla.org/MPL/
  13  *
  14  * Software distributed under the License is distributed on an "AS IS" basis,
  15  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  16  * for the specific language governing rights and limitations under the
  17  * License.
  18  *
  19  * The Original Code is the Nice GLib ICE library.
  20  *
  21  * The Initial Developers of the Original Code are Collabora Ltd and Nokia
  22  * Corporation. All Rights Reserved.
  23  *
  24  * Contributors:
  25  *   Youness Alaoui, Collabora Ltd.
  26  *   Rémi Denis-Courmont, Nokia
  27  *
  28  * Alternatively, the contents of this file may be used under the terms of the
  29  * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
  30  * case the provisions of LGPL are applicable instead of those above. If you
  31  * wish to allow use of your version of this file only under the terms of the
  32  * LGPL and not to allow others to use your version of this file under the
  33  * MPL, indicate your decision by deleting the provisions above and replace
  34  * them with the notice and other provisions required by the LGPL. If you do
  35  * not delete the provisions above, a recipient may use your version of this
  36  * file under either the MPL or the LGPL.
  37  */
  38
  39 #ifdef HAVE_CONFIG_H
  40 # include <config.h>
  41 #endif
  42
  43 #ifdef _WIN32
  44 #define WIN32_LEAN_AND_MEAN
  45 #include <windows.h>
  46 #else
  47 #include <unistd.h>
  48 #endif
  49
  50 #include "timer.h"
  51
  52 #include <stdlib.h> /* div() */
  53
  54 /*
  55  * Clock used throughout the STUN code.
  56  * STUN requires a monotonic 1kHz clock to operate properly.
  57  */
  58 static void stun_gettime (struct timeval *now)
  59 {
  60 #ifdef _WIN32
  61   FILETIME ft;
  62   unsigned long long *time64 = (unsigned long long *) &ft;
  63
  64   GetSystemTimeAsFileTime (&ft);
  65
  66   /* Convert from 100s of nanoseconds since 1601-01-01
  67    * to Unix epoch. Yes, this is Y2038 unsafe.
  68    */
  69   *time64 -= (unsigned long long) 116444736000000000;
  70   *time64 /= 10;
  71
  72   now->tv_sec = (long)(*time64 / 1000000);
  73   now->tv_usec = *time64 % 1000000;
  74 #else
  75 #if defined (_POSIX_MONOTONIC_CLOCK) && (_POSIX_MONOTONIC_CLOCK >= 0)
  76   struct timespec spec;
  77   if (!clock_gettime (CLOCK_MONOTONIC, &spec)) {
  78     now->tv_sec = spec.tv_sec;
  79     now->tv_usec = spec.tv_nsec / 1000;
  80   } else
  81 #endif
  82   {  // fallback to wall clock
  83     gettimeofday (now, NULL);
  84   }
  85 #endif
  86 }
  87
  88
  89 static void add_delay (struct timeval *ts, unsigned delay)
  90 {
  91   div_t d = div (delay, 1000);
  92   ts->tv_sec += d.quot;
  93   ts->tv_usec += d.rem * 1000;
  94
  95   while (ts->tv_usec > 1000000)
  96   {
  97     ts->tv_usec -= 1000000;
  98     ts->tv_sec++;
  99   }
 100 }
 101
 102
 103 void stun_timer_start (StunTimer *timer, unsigned int initial_timeout,
 104     unsigned int max_retransmissions)
 105 {
 106   stun_gettime (&timer->deadline);
 107   timer->retransmissions = 0;
 108   timer->delay = initial_timeout;
 109   timer->max_retransmissions = max_retransmissions;
 110   add_delay (&timer->deadline, timer->delay);
 111 }
 112
 113
 114 void stun_timer_start_reliable (StunTimer *timer, unsigned int initial_timeout)
 115 {
 116   stun_timer_start (timer, initial_timeout, 0);
 117 }
 118
 119
 120
 121 unsigned stun_timer_remainder (const StunTimer *timer)
 122 {
 123   unsigned delay;
 124   struct timeval now;
 125
 126   stun_gettime (&now);
 127   if (now.tv_sec > timer->deadline.tv_sec)
 128     return 0;
 129
 130   delay = timer->deadline.tv_sec - now.tv_sec;
 131   if ((delay == 0) && (now.tv_usec >= timer->deadline.tv_usec))
 132     return 0;
 133
 134   delay *= 1000;
 135   delay += ((signed)(timer->deadline.tv_usec - now.tv_usec)) / 1000;
 136   return delay;
 137 }
 138
 139
 140 StunUsageTimerReturn stun_timer_refresh (StunTimer *timer)
 141 {
 142   unsigned delay = stun_timer_remainder (timer);
 143   if (delay == 0)
 144   {
 145     if (timer->retransmissions >= timer->max_retransmissions)
 146       return STUN_USAGE_TIMER_RETURN_TIMEOUT;
 147
 148     add_delay (&timer->deadline, timer->delay *= 2);
 149     timer->retransmissions++;
 150     return STUN_USAGE_TIMER_RETURN_RETRANSMIT;
 151   }
 152
 153   return STUN_USAGE_TIMER_RETURN_SUCCESS;
 154 }