timer.c revision 118660 
1/*	$FreeBSD: head/usr.sbin/rtadvd/timer.c 118660 2003-08-08 16:38:23Z ume $	*/
2/*	$KAME: timer.c,v 1.4 2000/05/27 11:30:43 jinmei 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#if defined(__NetBSD__) || defined(__OpenBSD__)
40#include <search.h>
41#endif
42#include "timer.h"
43
44static struct rtadvd_timer timer_head;
45
46#define MILLION 1000000
47#define TIMEVAL_EQUAL(t1,t2) ((t1)->tv_sec == (t2)->tv_sec &&\
48 (t1)->tv_usec == (t2)->tv_usec)
49
50static struct timeval tm_max = {0x7fffffff, 0x7fffffff};
51
52void
53rtadvd_timer_init()
54{
55	memset(&timer_head, 0, sizeof(timer_head));
56
57	timer_head.next = timer_head.prev = &timer_head;
58	timer_head.tm = tm_max;
59}
60
61struct rtadvd_timer *
62rtadvd_add_timer(struct rtadvd_timer *(*timeout) __P((void *)),
63    void (*update) __P((void *, struct timeval *)),
64    void *timeodata, void *updatedata)
65{
66	struct rtadvd_timer *newtimer;
67
68	if ((newtimer = malloc(sizeof(*newtimer))) == NULL) {
69		syslog(LOG_ERR,
70		       "<%s> can't allocate memory", __func__);
71		exit(1);
72	}
73
74	memset(newtimer, 0, sizeof(*newtimer));
75
76	if (timeout == NULL) {
77		syslog(LOG_ERR,
78		       "<%s> timeout function unspecfied", __func__);
79		exit(1);
80	}
81	newtimer->expire = timeout;
82	newtimer->update = update;
83	newtimer->expire_data = timeodata;
84	newtimer->update_data = updatedata;
85	newtimer->tm = tm_max;
86
87	/* link into chain */
88	insque(newtimer, &timer_head);
89
90	return(newtimer);
91}
92
93void
94rtadvd_remove_timer(struct rtadvd_timer **timer)
95{
96	remque(*timer);
97	free(*timer);
98	*timer = NULL;
99}
100
101void
102rtadvd_set_timer(struct timeval *tm, struct rtadvd_timer *timer)
103{
104	struct timeval now;
105
106	/* reset the timer */
107	gettimeofday(&now, NULL);
108
109	TIMEVAL_ADD(&now, tm, &timer->tm);
110
111	/* update the next expiration time */
112	if (TIMEVAL_LT(timer->tm, timer_head.tm))
113		timer_head.tm = timer->tm;
114
115	return;
116}
117
118/*
119 * Check expiration for each timer. If a timer expires,
120 * call the expire function for the timer and update the timer.
121 * Return the next interval for select() call.
122 */
123struct timeval *
124rtadvd_check_timer()
125{
126	static struct timeval returnval;
127	struct timeval now;
128	struct rtadvd_timer *tm = timer_head.next, *tm_next;
129
130	gettimeofday(&now, NULL);
131
132	timer_head.tm = tm_max;
133
134	for (tm = timer_head.next; tm != &timer_head; tm = tm_next) {
135		tm_next = tm->next;
136
137		if (TIMEVAL_LEQ(tm->tm, now)) {
138			if (((*tm->expire)(tm->expire_data) == NULL))
139				continue; /* the timer was removed */
140			if (tm->update)
141				(*tm->update)(tm->update_data, &tm->tm);
142			TIMEVAL_ADD(&tm->tm, &now, &tm->tm);
143		}
144
145		if (TIMEVAL_LT(tm->tm, timer_head.tm))
146			timer_head.tm = tm->tm;
147	}
148
149	if (TIMEVAL_EQUAL(&tm_max, &timer_head.tm)) {
150		/* no need to timeout */
151		return(NULL);
152	}
153	else if (TIMEVAL_LT(timer_head.tm, now)) {
154		/* this may occur when the interval is too small */
155		returnval.tv_sec = returnval.tv_usec = 0;
156	}
157	else
158		TIMEVAL_SUB(&timer_head.tm, &now, &returnval);
159	return(&returnval);
160}
161
162struct timeval *
163rtadvd_timer_rest(struct rtadvd_timer *timer)
164{
165	static struct timeval returnval, now;
166
167	gettimeofday(&now, NULL);
168	if (TIMEVAL_LEQ(timer->tm, now)) {
169		syslog(LOG_DEBUG,
170		       "<%s> a timer must be expired, but not yet",
171		       __func__);
172		returnval.tv_sec = returnval.tv_usec = 0;
173	}
174	else
175		TIMEVAL_SUB(&timer->tm, &now, &returnval);
176
177	return(&returnval);
178}
179
180/* result = a + b */
181void
182TIMEVAL_ADD(struct timeval *a, struct timeval *b, struct timeval *result)
183{
184	long l;
185
186	if ((l = a->tv_usec + b->tv_usec) < MILLION) {
187		result->tv_usec = l;
188		result->tv_sec = a->tv_sec + b->tv_sec;
189	}
190	else {
191		result->tv_usec = l - MILLION;
192		result->tv_sec = a->tv_sec + b->tv_sec + 1;
193	}
194}
195
196/*
197 * result = a - b
198 * XXX: this function assumes that a >= b.
199 */
200void
201TIMEVAL_SUB(struct timeval *a, struct timeval *b, struct timeval *result)
202{
203	long l;
204
205	if ((l = a->tv_usec - b->tv_usec) >= 0) {
206		result->tv_usec = l;
207		result->tv_sec = a->tv_sec - b->tv_sec;
208	}
209	else {
210		result->tv_usec = MILLION + l;
211		result->tv_sec = a->tv_sec - b->tv_sec - 1;
212	}
213}
214