rtadvd.tproj/timer.c

   1 /*      $KAME: timer.c,v 1.9 2002/06/10 19:59:47 itojun Exp $   */
   2
   3 /*
   4  * Copyright (C) 1998 WIDE Project.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the project nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/time.h>
  33
  34 #include <unistd.h>
  35 #include <syslog.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <search.h>
  39 #include "timer.h"
  40
  41 static struct rtadvd_timer timer_head;
  42
  43 #define MILLION 1000000
  44 #define TIMEVAL_EQUAL(t1,t2) ((t1)->tv_sec == (t2)->tv_sec &&\
  45  (t1)->tv_usec == (t2)->tv_usec)
  46
  47 static struct timeval tm_max = {0x7fffffff, 0x7fffffff};
  48
  49 void
  50 rtadvd_timer_init()
  51 {
  52         memset(&timer_head, 0, sizeof(timer_head));
  53
  54         timer_head.next = timer_head.prev = &timer_head;
  55         timer_head.tm = tm_max;
  56 }
  57
  58 struct rtadvd_timer *
  59 rtadvd_add_timer(struct rtadvd_timer *(*timeout)(void *),
  60     void (*update)(void *, struct timeval *),
  61     void *timeodata, void *updatedata)
  62 {
  63         struct rtadvd_timer *newtimer;
  64
  65         if ((newtimer = malloc(sizeof(*newtimer))) == NULL) {
  66                 syslog(LOG_ERR,
  67                        "<%s> can't allocate memory", __func__);
  68                 exit(1);
  69         }
  70
  71         memset(newtimer, 0, sizeof(*newtimer));
  72
  73         if (timeout == NULL) {
  74                 syslog(LOG_ERR,
  75                        "<%s> timeout function unspecified", __func__);
  76                 exit(1);
  77         }
  78         newtimer->expire = timeout;
  79         newtimer->update = update;
  80         newtimer->expire_data = timeodata;
  81         newtimer->update_data = updatedata;
  82         newtimer->tm = tm_max;
  83
  84         /* link into chain */
  85         insque(newtimer, &timer_head);
  86
  87         return(newtimer);
  88 }
  89
  90 void
  91 rtadvd_remove_timer(struct rtadvd_timer **timer)
  92 {
  93         remque(*timer);
  94         free(*timer);
  95         *timer = NULL;
  96 }
  97
  98 void
  99 rtadvd_set_timer(struct timeval *tm, struct rtadvd_timer *timer)
 100 {
 101         struct timeval now;
 102
 103         /* reset the timer */
 104         gettimeofday(&now, NULL);
 105
 106         TIMEVAL_ADD(&now, tm, &timer->tm);
 107
 108         /* update the next expiration time */
 109         if (TIMEVAL_LT(timer->tm, timer_head.tm))
 110                 timer_head.tm = timer->tm;
 111
 112         return;
 113 }
 114
 115 /*
 116  * Check expiration for each timer. If a timer expires,
 117  * call the expire function for the timer and update the timer.
 118  * Return the next interval for select() call.
 119  */
 120 struct timeval *
 121 rtadvd_check_timer()
 122 {
 123         static struct timeval returnval;
 124         struct timeval now;
 125         struct rtadvd_timer *tm = timer_head.next, *tm_next;
 126
 127         gettimeofday(&now, NULL);
 128
 129         timer_head.tm = tm_max;
 130
 131         for (tm = timer_head.next; tm != &timer_head; tm = tm_next) {
 132                 tm_next = tm->next;
 133
 134                 if (TIMEVAL_LEQ(tm->tm, now)) {
 135                         if (((*tm->expire)(tm->expire_data) == NULL))
 136                                 continue; /* the timer was removed */
 137                         if (tm->update)
 138                                 (*tm->update)(tm->update_data, &tm->tm);
 139                         TIMEVAL_ADD(&tm->tm, &now, &tm->tm);
 140                 }
 141
 142                 if (TIMEVAL_LT(tm->tm, timer_head.tm))
 143                         timer_head.tm = tm->tm;
 144         }
 145
 146         if (TIMEVAL_EQUAL(&tm_max, &timer_head.tm)) {
 147                 /* no need to timeout */
 148                 return(NULL);
 149         } else if (TIMEVAL_LT(timer_head.tm, now)) {
 150                 /* this may occur when the interval is too small */
 151                 returnval.tv_sec = returnval.tv_usec = 0;
 152         } else
 153                 TIMEVAL_SUB(&timer_head.tm, &now, &returnval);
 154         return(&returnval);
 155 }
 156
 157 struct timeval *
 158 rtadvd_timer_rest(struct rtadvd_timer *timer)
 159 {
 160         static struct timeval returnval, now;
 161
 162         gettimeofday(&now, NULL);
 163         if (TIMEVAL_LEQ(timer->tm, now)) {
 164                 syslog(LOG_DEBUG,
 165                        "<%s> a timer must be expired, but not yet",
 166                        __func__);
 167                 returnval.tv_sec = returnval.tv_usec = 0;
 168         }
 169         else
 170                 TIMEVAL_SUB(&timer->tm, &now, &returnval);
 171
 172         return(&returnval);
 173 }
 174
 175 /* result = a + b */
 176 void
 177 TIMEVAL_ADD(struct timeval *a, struct timeval *b, struct timeval *result)
 178 {
 179         long l;
 180
 181         if ((l = a->tv_usec + b->tv_usec) < MILLION) {
 182                 result->tv_usec = l;
 183                 result->tv_sec = a->tv_sec + b->tv_sec;
 184         }
 185         else {
 186                 result->tv_usec = l - MILLION;
 187                 result->tv_sec = a->tv_sec + b->tv_sec + 1;
 188         }
 189 }
 190
 191 /*
 192  * result = a - b
 193  * XXX: this function assumes that a >= b.
 194  */
 195 void
 196 TIMEVAL_SUB(struct timeval *a, struct timeval *b, struct timeval *result)
 197 {
 198         long l;
 199
 200         if ((l = a->tv_usec - b->tv_usec) >= 0) {
 201                 result->tv_usec = l;
 202                 result->tv_sec = a->tv_sec - b->tv_sec;
 203         }
 204         else {
 205                 result->tv_usec = MILLION + l;
 206                 result->tv_sec = a->tv_sec - b->tv_sec - 1;
 207         }
 208 }