usr.sbin/rtadvd/timer.c

   1 /*      $KAME: timer.c,v 1.4 2000/05/27 11:30:43 jinmei 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  * $FreeBSD: src/usr.sbin/rtadvd/timer.c,v 1.1.2.3 2002/06/29 18:59:53 ume Exp $
  32  */
  33
  34 #include <sys/time.h>
  35
  36 #include <unistd.h>
  37 #include <syslog.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <search.h>
  41 #include "timer.h"
  42
  43 static struct rtadvd_timer timer_head;
  44
  45 #define MILLION 1000000
  46 #define TIMEVAL_EQUAL(t1,t2) ((t1)->tv_sec == (t2)->tv_sec &&\
  47  (t1)->tv_usec == (t2)->tv_usec)
  48
  49 static struct timeval tm_max = {0x7fffffff, 0x7fffffff};
  50
  51 void
  52 rtadvd_timer_init(void)
  53 {
  54         memset(&timer_head, 0, sizeof(timer_head));
  55
  56         timer_head.next = timer_head.prev = &timer_head;
  57         timer_head.tm = tm_max;
  58 }
  59
  60 struct rtadvd_timer *
  61 rtadvd_add_timer(struct rtadvd_timer *(*timeout)(void *),
  62     void (*update)(void *, struct timeval *),
  63     void *timeodata, void *updatedata)
  64 {
  65         struct rtadvd_timer *newtimer;
  66
  67         if ((newtimer = malloc(sizeof(*newtimer))) == NULL) {
  68                 syslog(LOG_ERR,
  69                        "<%s> can't allocate memory", __func__);
  70                 exit(1);
  71         }
  72
  73         memset(newtimer, 0, sizeof(*newtimer));
  74
  75         if (timeout == NULL) {
  76                 syslog(LOG_ERR,
  77                        "<%s> timeout function unspecfied", __func__);
  78                 exit(1);
  79         }
  80         newtimer->expire = timeout;
  81         newtimer->update = update;
  82         newtimer->expire_data = timeodata;
  83         newtimer->update_data = updatedata;
  84         newtimer->tm = tm_max;
  85
  86         /* link into chain */
  87         insque(newtimer, &timer_head);
  88
  89         return(newtimer);
  90 }
  91
  92 void
  93 rtadvd_remove_timer(struct rtadvd_timer **timer)
  94 {
  95         remque(*timer);
  96         free(*timer);
  97         *timer = NULL;
  98 }
  99
 100 void
 101 rtadvd_set_timer(struct timeval *tm, struct rtadvd_timer *timer)
 102 {
 103         struct timeval now;
 104
 105         /* reset the timer */
 106         gettimeofday(&now, NULL);
 107
 108         TIMEVAL_ADD(&now, tm, &timer->tm);
 109
 110         /* update the next expiration time */
 111         if (TIMEVAL_LT(timer->tm, timer_head.tm))
 112                 timer_head.tm = timer->tm;
 113
 114         return;
 115 }
 116
 117 /*
 118  * Check expiration for each timer. If a timer expires,
 119  * call the expire function for the timer and update the timer.
 120  * Return the next interval for select() call.
 121  */
 122 struct timeval *
 123 rtadvd_check_timer(void)
 124 {
 125         static struct timeval returnval;
 126         struct timeval now;
 127         struct rtadvd_timer *tm = timer_head.next, *tm_next;
 128
 129         gettimeofday(&now, NULL);
 130
 131         timer_head.tm = tm_max;
 132
 133         for (tm = timer_head.next; tm != &timer_head; tm = tm_next) {
 134                 tm_next = tm->next;
 135
 136                 if (TIMEVAL_LEQ(tm->tm, now)) {
 137                         if (((*tm->expire)(tm->expire_data) == NULL))
 138                                 continue; /* the timer was removed */
 139                         if (tm->update)
 140                                 (*tm->update)(tm->update_data, &tm->tm);
 141                         TIMEVAL_ADD(&tm->tm, &now, &tm->tm);
 142                 }
 143
 144                 if (TIMEVAL_LT(tm->tm, timer_head.tm))
 145                         timer_head.tm = tm->tm;
 146         }
 147
 148         if (TIMEVAL_EQUAL(&tm_max, &timer_head.tm)) {
 149                 /* no need to timeout */
 150                 return(NULL);
 151         }
 152         else if (TIMEVAL_LT(timer_head.tm, now)) {
 153                 /* this may occur when the interval is too small */
 154                 returnval.tv_sec = returnval.tv_usec = 0;
 155         }
 156         else
 157                 TIMEVAL_SUB(&timer_head.tm, &now, &returnval);
 158         return(&returnval);
 159 }
 160
 161 struct timeval *
 162 rtadvd_timer_rest(struct rtadvd_timer *timer)
 163 {
 164         static struct timeval returnval, now;
 165
 166         gettimeofday(&now, NULL);
 167         if (TIMEVAL_LEQ(timer->tm, now)) {
 168                 syslog(LOG_DEBUG,
 169                        "<%s> a timer must be expired, but not yet",
 170                        __func__);
 171                 returnval.tv_sec = returnval.tv_usec = 0;
 172         }
 173         else
 174                 TIMEVAL_SUB(&timer->tm, &now, &returnval);
 175
 176         return(&returnval);
 177 }
 178
 179 /* result = a + b */
 180 void
 181 TIMEVAL_ADD(struct timeval *a, struct timeval *b, struct timeval *result)
 182 {
 183         long l;
 184
 185         if ((l = a->tv_usec + b->tv_usec) < MILLION) {
 186                 result->tv_usec = l;
 187                 result->tv_sec = a->tv_sec + b->tv_sec;
 188         }
 189         else {
 190                 result->tv_usec = l - MILLION;
 191                 result->tv_sec = a->tv_sec + b->tv_sec + 1;
 192         }
 193 }
 194
 195 /*
 196  * result = a - b
 197  * XXX: this function assumes that a >= b.
 198  */
 199 void
 200 TIMEVAL_SUB(struct timeval *a, struct timeval *b, struct timeval *result)
 201 {
 202         long l;
 203
 204         if ((l = a->tv_usec - b->tv_usec) >= 0) {
 205                 result->tv_usec = l;
 206                 result->tv_sec = a->tv_sec - b->tv_sec;
 207         }
 208         else {
 209                 result->tv_usec = MILLION + l;
 210                 result->tv_sec = a->tv_sec - b->tv_sec - 1;
 211         }
 212 }