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  * $DragonFly: src/usr.sbin/rtadvd/timer.c,v 1.5 2005/12/05 00:56:37 swildner Exp $
  33  */
  34
  35 #include <sys/time.h>
  36
  37 #include <unistd.h>
  38 #include <syslog.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #if defined(__NetBSD__) || defined(__OpenBSD__)
  42 #include <search.h>
  43 #endif
  44 #include "timer.h"
  45
  46 static struct rtadvd_timer timer_head;
  47
  48 #define MILLION 1000000
  49 #define TIMEVAL_EQUAL(t1,t2) ((t1)->tv_sec == (t2)->tv_sec &&\
  50  (t1)->tv_usec == (t2)->tv_usec)
  51
  52 static struct timeval tm_max = {0x7fffffff, 0x7fffffff};
  53
  54 void
  55 rtadvd_timer_init(void)
  56 {
  57         memset(&timer_head, 0, sizeof(timer_head));
  58
  59         timer_head.next = timer_head.prev = &timer_head;
  60         timer_head.tm = tm_max;
  61 }
  62
  63 struct rtadvd_timer *
  64 rtadvd_add_timer(struct rtadvd_timer *(*timeout)(void *),
  65     void (*update)(void *, struct timeval *),
  66     void *timeodata, void *updatedata)
  67 {
  68         struct rtadvd_timer *newtimer;
  69
  70         if ((newtimer = malloc(sizeof(*newtimer))) == NULL) {
  71                 syslog(LOG_ERR,
  72                        "<%s> can't allocate memory", __func__);
  73                 exit(1);
  74         }
  75
  76         memset(newtimer, 0, sizeof(*newtimer));
  77
  78         if (timeout == NULL) {
  79                 syslog(LOG_ERR,
  80                        "<%s> timeout function unspecfied", __func__);
  81                 exit(1);
  82         }
  83         newtimer->expire = timeout;
  84         newtimer->update = update;
  85         newtimer->expire_data = timeodata;
  86         newtimer->update_data = updatedata;
  87         newtimer->tm = tm_max;
  88
  89         /* link into chain */
  90         insque(newtimer, &timer_head);
  91
  92         return(newtimer);
  93 }
  94
  95 void
  96 rtadvd_remove_timer(struct rtadvd_timer **timer)
  97 {
  98         remque(*timer);
  99         free(*timer);
 100         *timer = NULL;
 101 }
 102
 103 void
 104 rtadvd_set_timer(struct timeval *tm, struct rtadvd_timer *timer)
 105 {
 106         struct timeval now;
 107
 108         /* reset the timer */
 109         gettimeofday(&now, NULL);
 110
 111         TIMEVAL_ADD(&now, tm, &timer->tm);
 112
 113         /* update the next expiration time */
 114         if (TIMEVAL_LT(timer->tm, timer_head.tm))
 115                 timer_head.tm = timer->tm;
 116
 117         return;
 118 }
 119
 120 /*
 121  * Check expiration for each timer. If a timer expires,
 122  * call the expire function for the timer and update the timer.
 123  * Return the next interval for select() call.
 124  */
 125 struct timeval *
 126 rtadvd_check_timer(void)
 127 {
 128         static struct timeval returnval;
 129         struct timeval now;
 130         struct rtadvd_timer *tm = timer_head.next, *tm_next;
 131
 132         gettimeofday(&now, NULL);
 133
 134         timer_head.tm = tm_max;
 135
 136         for (tm = timer_head.next; tm != &timer_head; tm = tm_next) {
 137                 tm_next = tm->next;
 138
 139                 if (TIMEVAL_LEQ(tm->tm, now)) {
 140                         if (((*tm->expire)(tm->expire_data) == NULL))
 141                                 continue; /* the timer was removed */
 142                         if (tm->update)
 143                                 (*tm->update)(tm->update_data, &tm->tm);
 144                         TIMEVAL_ADD(&tm->tm, &now, &tm->tm);
 145                 }
 146
 147                 if (TIMEVAL_LT(tm->tm, timer_head.tm))
 148                         timer_head.tm = tm->tm;
 149         }
 150
 151         if (TIMEVAL_EQUAL(&tm_max, &timer_head.tm)) {
 152                 /* no need to timeout */
 153                 return(NULL);
 154         }
 155         else if (TIMEVAL_LT(timer_head.tm, now)) {
 156                 /* this may occur when the interval is too small */
 157                 returnval.tv_sec = returnval.tv_usec = 0;
 158         }
 159         else
 160                 TIMEVAL_SUB(&timer_head.tm, &now, &returnval);
 161         return(&returnval);
 162 }
 163
 164 struct timeval *
 165 rtadvd_timer_rest(struct rtadvd_timer *timer)
 166 {
 167         static struct timeval returnval, now;
 168
 169         gettimeofday(&now, NULL);
 170         if (TIMEVAL_LEQ(timer->tm, now)) {
 171                 syslog(LOG_DEBUG,
 172                        "<%s> a timer must be expired, but not yet",
 173                        __func__);
 174                 returnval.tv_sec = returnval.tv_usec = 0;
 175         }
 176         else
 177                 TIMEVAL_SUB(&timer->tm, &now, &returnval);
 178
 179         return(&returnval);
 180 }
 181
 182 /* result = a + b */
 183 void
 184 TIMEVAL_ADD(struct timeval *a, struct timeval *b, struct timeval *result)
 185 {
 186         long l;
 187
 188         if ((l = a->tv_usec + b->tv_usec) < MILLION) {
 189                 result->tv_usec = l;
 190                 result->tv_sec = a->tv_sec + b->tv_sec;
 191         }
 192         else {
 193                 result->tv_usec = l - MILLION;
 194                 result->tv_sec = a->tv_sec + b->tv_sec + 1;
 195         }
 196 }
 197
 198 /*
 199  * result = a - b
 200  * XXX: this function assumes that a >= b.
 201  */
 202 void
 203 TIMEVAL_SUB(struct timeval *a, struct timeval *b, struct timeval *result)
 204 {
 205         long l;
 206
 207         if ((l = a->tv_usec - b->tv_usec) >= 0) {
 208                 result->tv_usec = l;
 209                 result->tv_sec = a->tv_sec - b->tv_sec;
 210         }
 211         else {
 212                 result->tv_usec = MILLION + l;
 213                 result->tv_sec = a->tv_sec - b->tv_sec - 1;
 214         }
 215 }