1 /* $NetBSD: timer.c,v 1.11 2012/12/13 15:36:36 roy 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/queue.h> 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 struct rtadvd_timer_head_t ra_timer = TAILQ_HEAD_INITIALIZER(ra_timer); 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_limit = {0x7fffffff, 0x7fffffff}; 50 static struct timeval tm_max; 51 52 void 53 rtadvd_timer_init(void) 54 { 55 56 TAILQ_INIT(&ra_timer); 57 tm_max = tm_limit; 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 unspecified", __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 TAILQ_INSERT_TAIL(&ra_timer, newtimer, next); 88 89 return(newtimer); 90 } 91 92 void 93 rtadvd_remove_timer(struct rtadvd_timer **timer) 94 { 95 96 if (*timer) { 97 TAILQ_REMOVE(&ra_timer, *timer, next); 98 free(*timer); 99 *timer = NULL; 100 } 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, tm_max)) 115 tm_max = 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, *tmn; 131 132 gettimeofday(&now, NULL); 133 tm_max = tm_limit; 134 135 TAILQ_FOREACH_SAFE(tm, &ra_timer, next, tmn) { 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, tm_max)) 145 tm_max = tm->tm; 146 } 147 148 if (TIMEVAL_EQUAL(&tm_max, &tm_limit)) { 149 /* no need to timeout */ 150 return(NULL); 151 } else if (TIMEVAL_LT(tm_max, now)) { 152 /* this may occur when the interval is too small */ 153 returnval.tv_sec = returnval.tv_usec = 0; 154 } else 155 TIMEVAL_SUB(&tm_max, &now, &returnval); 156 return(&returnval); 157 } 158 159 struct timeval * 160 rtadvd_timer_rest(struct rtadvd_timer *timer) 161 { 162 static struct timeval returnval, now; 163 164 gettimeofday(&now, NULL); 165 if (TIMEVAL_LEQ(timer->tm, now)) { 166 syslog(LOG_DEBUG, 167 "<%s> a timer must be expired, but not yet", 168 __func__); 169 returnval.tv_sec = returnval.tv_usec = 0; 170 } 171 else 172 TIMEVAL_SUB(&timer->tm, &now, &returnval); 173 174 return(&returnval); 175 } 176 177 /* result = a + b */ 178 void 179 TIMEVAL_ADD(struct timeval *a, struct timeval *b, struct timeval *result) 180 { 181 long l; 182 183 if ((l = a->tv_usec + b->tv_usec) < MILLION) { 184 result->tv_usec = l; 185 result->tv_sec = a->tv_sec + b->tv_sec; 186 } 187 else { 188 result->tv_usec = l - MILLION; 189 result->tv_sec = a->tv_sec + b->tv_sec + 1; 190 } 191 } 192 193 /* 194 * result = a - b 195 * XXX: this function assumes that a >= b. 196 */ 197 void 198 TIMEVAL_SUB(struct timeval *a, struct timeval *b, struct timeval *result) 199 { 200 long l; 201 202 if ((l = a->tv_usec - b->tv_usec) >= 0) { 203 result->tv_usec = l; 204 result->tv_sec = a->tv_sec - b->tv_sec; 205 } 206 else { 207 result->tv_usec = MILLION + l; 208 result->tv_sec = a->tv_sec - b->tv_sec - 1; 209 } 210 } 211