usr.sbin/rtadvd/timer.c

   1 /*      $NetBSD: timer.c,v 1.8 2002/07/10 21:11:44 itojun Exp $ */
   2 /*      $KAME: timer.c,v 1.11 2005/04/14 06:22:35 suz Exp $     */
   3
   4 /*
   5  * Copyright (C) 1998 WIDE Project.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the project nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <sys/time.h>
  34
  35 #include <unistd.h>
  36 #include <syslog.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <search.h>
  40 #include "timer.h"
  41
  42 static struct rtadvd_timer timer_head;
  43
  44 #define MILLION 1000000
  45 #define TIMEVAL_EQUAL(t1,t2) ((t1)->tv_sec == (t2)->tv_sec &&\
  46  (t1)->tv_usec == (t2)->tv_usec)
  47
  48 static struct timeval tm_max = {0x7fffffff, 0x7fffffff};
  49
  50 void
  51 rtadvd_timer_init()
  52 {
  53         memset(&timer_head, 0, sizeof(timer_head));
  54
  55         timer_head.next = timer_head.prev = &timer_head;
  56         timer_head.tm = tm_max;
  57 }
  58
  59 struct rtadvd_timer *
  60 rtadvd_add_timer(struct rtadvd_timer *(*timeout) __P((void *)),
  61     void (*update) __P((void *, struct timeval *)),
  62     void *timeodata, void *updatedata)
  63 {
  64         struct rtadvd_timer *newtimer;
  65
  66         if ((newtimer = malloc(sizeof(*newtimer))) == NULL) {
  67                 syslog(LOG_ERR,
  68                        "<%s> can't allocate memory", __func__);
  69                 exit(1);
  70         }
  71
  72         memset(newtimer, 0, sizeof(*newtimer));
  73
  74         if (timeout == NULL) {
  75                 syslog(LOG_ERR,
  76                        "<%s> timeout function unspecified", __func__);
  77                 exit(1);
  78         }
  79         newtimer->expire = timeout;
  80         newtimer->update = update;
  81         newtimer->expire_data = timeodata;
  82         newtimer->update_data = updatedata;
  83         newtimer->tm = tm_max;
  84
  85         /* link into chain */
  86         insque(newtimer, &timer_head);
  87
  88         return(newtimer);
  89 }
  90
  91 void
  92 rtadvd_remove_timer(struct rtadvd_timer **timer)
  93 {
  94         remque(*timer);
  95         free(*timer);
  96         *timer = NULL;
  97 }
  98
  99 void
 100 rtadvd_set_timer(struct timeval *tm, struct rtadvd_timer *timer)
 101 {
 102         struct timeval now;
 103
 104         /* reset the timer */
 105         gettimeofday(&now, NULL);
 106
 107         TIMEVAL_ADD(&now, tm, &timer->tm);
 108
 109         /* update the next expiration time */
 110         if (TIMEVAL_LT(timer->tm, timer_head.tm))
 111                 timer_head.tm = timer->tm;
 112
 113         return;
 114 }
 115
 116 /*
 117  * Check expiration for each timer. If a timer expires,
 118  * call the expire function for the timer and update the timer.
 119  * Return the next interval for select() call.
 120  */
 121 struct timeval *
 122 rtadvd_check_timer()
 123 {
 124         static struct timeval returnval;
 125         struct timeval now;
 126         struct rtadvd_timer *tm = timer_head.next, *tm_next;
 127
 128         gettimeofday(&now, NULL);
 129
 130         timer_head.tm = tm_max;
 131
 132         for (tm = timer_head.next; tm != &timer_head; tm = tm_next) {
 133                 tm_next = tm->next;
 134
 135                 if (TIMEVAL_LEQ(tm->tm, now)) {
 136                         if ((*tm->expire)(tm->expire_data) == NULL)
 137                                 continue; /* the timer was removed */
 138                         if (tm->update)
 139                                 (*tm->update)(tm->update_data, &tm->tm);
 140                         TIMEVAL_ADD(&tm->tm, &now, &tm->tm);
 141                 }
 142
 143                 if (TIMEVAL_LT(tm->tm, timer_head.tm))
 144                         timer_head.tm = tm->tm;
 145         }
 146
 147         if (TIMEVAL_EQUAL(&tm_max, &timer_head.tm)) {
 148                 /* no need to timeout */
 149                 return(NULL);
 150         } else if (TIMEVAL_LT(timer_head.tm, now)) {
 151                 /* this may occur when the interval is too small */
 152                 returnval.tv_sec = returnval.tv_usec = 0;
 153         } else
 154                 TIMEVAL_SUB(&timer_head.tm, &now, &returnval);
 155         return(&returnval);
 156 }
 157
 158 struct timeval *
 159 rtadvd_timer_rest(struct rtadvd_timer *timer)
 160 {
 161         static struct timeval returnval, now;
 162
 163         gettimeofday(&now, NULL);
 164         if (TIMEVAL_LEQ(timer->tm, now)) {
 165                 syslog(LOG_DEBUG,
 166                        "<%s> a timer must be expired, but not yet",
 167                        __func__);
 168                 returnval.tv_sec = returnval.tv_usec = 0;
 169         }
 170         else
 171                 TIMEVAL_SUB(&timer->tm, &now, &returnval);
 172
 173         return(&returnval);
 174 }
 175
 176 /* result = a + b */
 177 void
 178 TIMEVAL_ADD(struct timeval *a, struct timeval *b, struct timeval *result)
 179 {
 180         long l;
 181
 182         if ((l = a->tv_usec + b->tv_usec) < MILLION) {
 183                 result->tv_usec = l;
 184                 result->tv_sec = a->tv_sec + b->tv_sec;
 185         }
 186         else {
 187                 result->tv_usec = l - MILLION;
 188                 result->tv_sec = a->tv_sec + b->tv_sec + 1;
 189         }
 190 }
 191
 192 /*
 193  * result = a - b
 194  * XXX: this function assumes that a >= b.
 195  */
 196 void
 197 TIMEVAL_SUB(struct timeval *a, struct timeval *b, struct timeval *result)
 198 {
 199         long l;
 200
 201         if ((l = a->tv_usec - b->tv_usec) >= 0) {
 202                 result->tv_usec = l;
 203                 result->tv_sec = a->tv_sec - b->tv_sec;
 204         }
 205         else {
 206                 result->tv_usec = MILLION + l;
 207                 result->tv_sec = a->tv_sec - b->tv_sec - 1;
 208         }
 209 }