stun/timer.c

   1 /*
   2  * This file is part of the Nice GLib ICE library.
   3  *
   4  * (C) 2007 Nokia Corporation. All rights reserved.
   5  *  Contact: Rémi Denis-Courmont
   6  *
   7  * The contents of this file are subject to the Mozilla Public License Version
   8  * 1.1 (the "License"); you may not use this file except in compliance with
   9  * the License. You may obtain a copy of the License at
  10  * http://www.mozilla.org/MPL/
  11  *
  12  * Software distributed under the License is distributed on an "AS IS" basis,
  13  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  14  * for the specific language governing rights and limitations under the
  15  * License.
  16  *
  17  * The Original Code is the Nice GLib ICE library.
  18  *
  19  * The Initial Developers of the Original Code are Collabora Ltd and Nokia
  20  * Corporation. All Rights Reserved.
  21  *
  22  * Contributors:
  23  *   Rémi Denis-Courmont, Nokia
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of the
  26  * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
  27  * case the provisions of LGPL are applicable instead of those above. If you
  28  * wish to allow use of your version of this file only under the terms of the
  29  * LGPL and not to allow others to use your version of this file under the
  30  * MPL, indicate your decision by deleting the provisions above and replace
  31  * them with the notice and other provisions required by the LGPL. If you do
  32  * not delete the provisions above, a recipient may use your version of this
  33  * file under either the MPL or the LGPL.
  34  */
  35
  36 #ifdef HAVE_CONFIG_H
  37 # include <config.h>
  38 #endif
  39
  40 #include "timer.h"
  41
  42 #include <stdlib.h> /* div() */
  43 #include <time.h>
  44
  45 #include <sys/types.h>
  46 #include <sys/time.h>
  47 #include <unistd.h>
  48
  49
  50 /**
  51  * Initial STUN timeout (milliseconds). The spec says it should be 100ms,
  52  * but that's way too short for most types of wireless Internet access.
  53  */
  54 #define STUN_INIT_TIMEOUT 600
  55 #define STUN_END_TIMEOUT 4800
  56
  57 #define STUN_RELIABLE_TIMEOUT 7900
  58
  59 /**
  60  * Clock used throughout the STUN code.
  61  * STUN requires a monotonic 1kHz clock to operate properly.
  62  */
  63 static void stun_gettime (struct timespec *restrict now)
  64 {
  65 #if (_POSIX_MONOTONIC_CLOCK - 0) >= 0
  66   if (clock_gettime (CLOCK_MONOTONIC, now))
  67 #endif
  68   {  // fallback to wall clock
  69     struct timeval tv;
  70     gettimeofday (&tv, NULL);
  71     now->tv_sec = tv.tv_sec;
  72     now->tv_nsec = tv.tv_usec * 1000;
  73   }
  74 }
  75
  76
  77 static inline void add_delay (struct timespec *ts, unsigned delay)
  78 {
  79   div_t d = div (delay, 1000);
  80   ts->tv_sec += d.quot;
  81   ts->tv_nsec += d.rem * 1000000;
  82
  83   while (ts->tv_nsec > 1000000000)
  84   {
  85     ts->tv_nsec -= 1000000000;
  86     ts->tv_sec++;
  87   }
  88 }
  89
  90
  91 void stun_timer_start (stun_timer_t *timer)
  92 {
  93   stun_gettime (&timer->deadline);
  94   add_delay (&timer->deadline, timer->delay = STUN_INIT_TIMEOUT);
  95 }
  96
  97
  98 void stun_timer_start_reliable (stun_timer_t *timer)
  99 {
 100   stun_gettime (&timer->deadline);
 101   add_delay (&timer->deadline, timer->delay = STUN_RELIABLE_TIMEOUT);
 102 }
 103
 104
 105
 106 unsigned stun_timer_remainder (const stun_timer_t *timer)
 107 {
 108   unsigned delay;
 109   struct timespec now;
 110
 111   stun_gettime (&now);
 112   if (now.tv_sec > timer->deadline.tv_sec)
 113     return 0;
 114
 115   delay = timer->deadline.tv_sec - now.tv_sec;
 116   if ((delay == 0) && (now.tv_nsec >= timer->deadline.tv_nsec))
 117     return 0;
 118
 119   delay *= 1000;
 120   delay += ((signed)(timer->deadline.tv_nsec - now.tv_nsec)) / 1000000;
 121   return delay;
 122 }
 123
 124
 125 int stun_timer_refresh (stun_timer_t *timer)
 126 {
 127   unsigned delay = stun_timer_remainder (timer);
 128   if (delay == 0)
 129   {
 130 #if STUN_RELIABLE_TIMEOUT < STUN_END_TIMEOUT
 131 /* Reliable timeout MUST be bigger (or equal) to end timeout, so that
 132  * retransmissions never happen with reliable transports. */
 133 # error Inconsistent STUN timeout values!
 134 #endif
 135     if (timer->delay >= STUN_END_TIMEOUT)
 136       return -1;
 137
 138     add_delay (&timer->deadline, timer->delay *= 2);
 139   }
 140
 141   return delay;
 142 }