/*      $NetBSD: timer.c,v 1.20 2021/03/23 18:16:53 christos Exp $      */
/*      $KAME: timer.c,v 1.11 2005/04/14 06:22:35 suz Exp $     */

/*
* Copyright (C) 1998 WIDE Project.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/queue.h>
#include <sys/time.h>

#include <assert.h>
#include <limits.h>
#include <unistd.h>
#include <syslog.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <search.h>
#include "timer.h"
#include "logit.h"
#include "prog_ops.h"

struct rtadvd_timer_head_t ra_timer = TAILQ_HEAD_INITIALIZER(ra_timer);
static struct timespec tm_limit = { LONG_MAX, 1000000000L - 1 };
static struct timespec tm_max;

void
rtadvd_timer_init(void)
{

       TAILQ_INIT(&ra_timer);
       tm_max = tm_limit;
}

struct rtadvd_timer *
rtadvd_add_timer(struct rtadvd_timer *(*timeout) (void *),
   void (*update) (void *, struct timespec *),
   void *timeodata, void *updatedata)
{
       struct rtadvd_timer *newtimer;

       assert(timeout != NULL);

       if ((newtimer = malloc(sizeof(*newtimer))) == NULL) {
               logit(LOG_ERR, "%s: malloc: %m", __func__);
               exit(EXIT_FAILURE);
       }

       memset(newtimer, 0, sizeof(*newtimer));

       newtimer->expire = timeout;
       newtimer->update = update;
       newtimer->expire_data = timeodata;
       newtimer->update_data = updatedata;
       newtimer->tm = tm_max;

       /* link into chain */
       TAILQ_INSERT_TAIL(&ra_timer, newtimer, next);

       return(newtimer);
}

void
rtadvd_remove_timer(struct rtadvd_timer **timer)
{

       if (*timer) {
               TAILQ_REMOVE(&ra_timer, *timer, next);
               free(*timer);
               *timer = NULL;
       }
}

void
rtadvd_set_timer(struct timespec *tm, struct rtadvd_timer *timer)
{
       struct timespec now;

       /* reset the timer */
       prog_clock_gettime(CLOCK_MONOTONIC, &now);
       timespecadd(&now, tm, &timer->tm);

       /* update the next expiration time */
       if (timespeccmp(&timer->tm, &tm_max, <))
               tm_max = timer->tm;

       /* enable the timer */
       timer->enabled = true;
}

/*
* Check expiration for each timer. If a timer expires,
* call the expire function for the timer and update the timer.
* Return the next interval for select() call.
*/
struct timespec *
rtadvd_check_timer(void)
{
       static struct timespec returnval;
       struct timespec now;
       struct rtadvd_timer *tm, *tmn;

       prog_clock_gettime(CLOCK_MONOTONIC, &now);
       tm_max = tm_limit;

       TAILQ_FOREACH_SAFE(tm, &ra_timer, next, tmn) {
               if (!tm->enabled)
                       continue;
               if (timespeccmp(&tm->tm, &now, <=)) {
                       if ((*tm->expire)(tm->expire_data) == NULL)
                               continue; /* the timer was removed */
                       if (tm->update)
                               (*tm->update)(tm->update_data, &tm->tm);
                       timespecadd(&tm->tm, &now, &tm->tm);
               }
               if (timespeccmp(&tm->tm, &tm_max, <))
                       tm_max = tm->tm;
       }

       if (timespeccmp(&tm_max, &tm_limit, ==))
               return(NULL);
       if (timespeccmp(&tm_max, &now, <)) {
               /* this may occur when the interval is too small */
               timespecclear(&returnval);
       } else
               timespecsub(&tm_max, &now, &returnval);
       return(&returnval);
}

struct timespec *
rtadvd_timer_rest(struct rtadvd_timer *timer)
{
       static struct timespec returnval;
       struct timespec now;

       prog_clock_gettime(CLOCK_MONOTONIC, &now);
       if (timespeccmp(&timer->tm, &now, <=)) {
               if (timer->enabled)
                       logit(LOG_DEBUG,
                              "%s: a timer must be expired, but not yet",
                              __func__);
               returnval.tv_sec = 0;
               returnval.tv_nsec = 0;
       }
       else
               timespecsub(&timer->tm, &now, &returnval);

       return(&returnval);
}