/*      $KAME: timer.c,v 1.9 2002/06/10 19:59:47 itojun Exp $   */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (C) 1998 WIDE Project.
 * Copyright (C) 2011 Hiroki Sato <hrs@FreeBSD.org>
 * 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/socket.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <netinet/in.h>

#include <unistd.h>
#include <syslog.h>
#include <stdlib.h>
#include <string.h>
#include <search.h>
#include <time.h>
#include <netdb.h>

#include "rtadvd.h"
#include "timer_subr.h"
#include "timer.h"

struct rtadvd_timer_head_t ra_timer =
    TAILQ_HEAD_INITIALIZER(ra_timer);
static struct timespec tm_limit;
static struct timespec tm_max;

void
rtadvd_timer_init(void)
{
        /* Generate maximum time in timespec. */
        tm_limit.tv_sec = (-1) & ~((time_t)1 << ((sizeof(tm_max.tv_sec) * 8) - 1));
        tm_limit.tv_nsec = (-1) & ~((long)1 << ((sizeof(tm_max.tv_nsec) * 8) - 1));
        tm_max = tm_limit;
        TAILQ_INIT(&ra_timer);
}

void
rtadvd_update_timeout_handler(void)
{
        struct ifinfo *ifi;

        TAILQ_FOREACH(ifi, &ifilist, ifi_next) {
                switch (ifi->ifi_state) {
                case IFI_STATE_CONFIGURED:
                case IFI_STATE_TRANSITIVE:
                        if (ifi->ifi_ra_timer != NULL)
                                continue;

                        syslog(LOG_DEBUG, "<%s> add timer for %s (idx=%d)",
                            __func__, ifi->ifi_ifname, ifi->ifi_ifindex);
                        ifi->ifi_ra_timer = rtadvd_add_timer(ra_timeout,
                            ra_timer_update, ifi, ifi);
                        ra_timer_update((void *)ifi,
                            &ifi->ifi_ra_timer->rat_tm);
                        rtadvd_set_timer(&ifi->ifi_ra_timer->rat_tm,
                            ifi->ifi_ra_timer);
                        break;
                case IFI_STATE_UNCONFIGURED:
                        if (ifi->ifi_ra_timer == NULL)
                                continue;

                        syslog(LOG_DEBUG,
                            "<%s> remove timer for %s (idx=%d)", __func__,
                            ifi->ifi_ifname, ifi->ifi_ifindex);
                        rtadvd_remove_timer(ifi->ifi_ra_timer);
                        ifi->ifi_ra_timer = NULL;
                        break;
                }
        }
}

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

        if (timeout == NULL) {
                syslog(LOG_ERR,
                    "<%s> timeout function unspecified", __func__);
                exit(1);
        }

        rat = malloc(sizeof(*rat));
        if (rat == NULL) {
                syslog(LOG_ERR,
                    "<%s> can't allocate memory", __func__);
                exit(1);
        }
        memset(rat, 0, sizeof(*rat));

        rat->rat_expire = timeout;
        rat->rat_update = update;
        rat->rat_expire_data = timeodata;
        rat->rat_update_data = updatedata;
        rat->rat_tm = tm_max;

        /* link into chain */
        TAILQ_INSERT_TAIL(&ra_timer, rat, rat_next);

        return (rat);
}

void
rtadvd_remove_timer(struct rtadvd_timer *rat)
{

        if (rat == NULL)
                return;

        TAILQ_REMOVE(&ra_timer, rat, rat_next);
        free(rat);
}

/*
 * 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 *rat;

        clock_gettime(CLOCK_MONOTONIC_FAST, &now);
        tm_max = tm_limit;
        TAILQ_FOREACH(rat, &ra_timer, rat_next) {
                if (TS_CMP(&rat->rat_tm, &now, <=)) {
                        if (((*rat->rat_expire)(rat->rat_expire_data) == NULL))
                                continue; /* the timer was removed */
                        if (rat->rat_update)
                                (*rat->rat_update)(rat->rat_update_data, &rat->rat_tm);
                        TS_ADD(&rat->rat_tm, &now, &rat->rat_tm);
                }
                if (TS_CMP(&rat->rat_tm, &tm_max, <))
                        tm_max = rat->rat_tm;
        }
        if (TS_CMP(&tm_max, &tm_limit, ==)) {
                /* no need to timeout */
                return (NULL);
        } else if (TS_CMP(&tm_max, &now, <)) {
                /* this may occur when the interval is too small */
                returnval.tv_sec = returnval.tv_nsec = 0;
        } else
                TS_SUB(&tm_max, &now, &returnval);
        return (&returnval);
}

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

        /* reset the timer */
        clock_gettime(CLOCK_MONOTONIC_FAST, &now);
        TS_ADD(&now, tm, &rat->rat_tm);

        /* update the next expiration time */
        if (TS_CMP(&rat->rat_tm, &tm_max, <))
                tm_max = rat->rat_tm;
}