/*      $KAME: rtsold.c,v 1.67 2003/05/17 18:16:15 itojun Exp $ */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (C) 1995, 1996, 1997, and 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/param.h>
#include <sys/capsicum.h>
#include <sys/event.h>
#include <sys/ioctl.h>
#include <sys/socket.h>

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

#include <netinet/in.h>
#include <netinet/icmp6.h>
#include <netinet/in_var.h>
#include <arpa/inet.h>

#include <netinet6/nd6.h>

#include <capsicum_helpers.h>
#include <err.h>
#include <errno.h>
#include <ifaddrs.h>
#include <libgen.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>

#include <libcasper.h>
#include <casper/cap_syslog.h>
#include <libutil.h>

#include "rtsold.h"

#define RTSOL_DUMPFILE  "/var/run/rtsold.dump"

struct timespec tm_max;
static int log_upto = 999;
static int fflag = 0;

int Fflag = 0;  /* force setting sysctl parameters */
int aflag = 0;
int dflag = 0;
int uflag = 0;

const char *managedconf_script;
const char *otherconf_script;
const char *alwaysconf_script;
const char *resolvconf_script = "/sbin/resolvconf";

cap_channel_t *capllflags, *capscript, *capsendmsg, *capsyslog;

/* protocol constants */
#define MAX_RTR_SOLICITATION_DELAY      1 /* second */
#define RTR_SOLICITATION_INTERVAL       4 /* seconds */
#define MAX_RTR_SOLICITATIONS           3 /* times */

/*
 * implementation dependent constants in seconds
 * XXX: should be configurable
 */
#define PROBE_INTERVAL 60

/* static variables and functions */
static int mobile_node = 0;
static int no_solicitation_delay = 0;

static sig_atomic_t do_dump, do_exit;
static struct pidfh *pfh;

static char **autoifprobe(void);
static int ifconfig(char *ifname);
static int init_capabilities(void);
static int make_packet(struct ifinfo *);
static struct timespec *rtsol_check_timer(void);

static void set_dumpfile(int);
static void set_exit(int);
static void usage(const char *progname);

int
main(int argc, char **argv)
{
        struct kevent events[2];
        FILE *dumpfp;
        struct ifinfo *ifi;
        struct timespec *timeout;
        const char *opts, *pidfilepath, *progname;
        int ch, error, kq, once, rcvsock, rtsock;

        progname = basename(argv[0]);
        if (strcmp(progname, "rtsold") == 0) {
                opts = "adDfFim1M:O:A:p:R:u";
                once = 0;
                pidfilepath = NULL;
        } else {
                opts = "adDFiM:O:A:R:u";
                fflag = 1;
                once = 1;
        }

        while ((ch = getopt(argc, argv, opts)) != -1) {
                switch (ch) {
                case 'a':
                        aflag = 1;
                        break;
                case 'd':
                        dflag += 1;
                        break;
                case 'D':
                        dflag += 2;
                        break;
                case 'f':
                        fflag = 1;
                        break;
                case 'F':
                        Fflag = 1;
                        break;
                case 'i':
                        no_solicitation_delay = 1;
                        break;
                case 'm':
                        mobile_node = 1;
                        break;
                case '1':
                        once = 1;
                        break;
                case 'M':
                        managedconf_script = optarg;
                        break;
                case 'O':
                        otherconf_script = optarg;
                        break;
                case 'A':
                        alwaysconf_script = optarg;
                        break;
                case 'p':
                        pidfilepath = optarg;
                        break;
                case 'R':
                        resolvconf_script = optarg;
                        break;
                case 'u':
                        uflag = 1;
                        break;
                default:
                        usage(progname);
                }
        }
        argc -= optind;
        argv += optind;

        if ((!aflag && argc == 0) || (aflag && argc != 0))
                usage(progname);

        /* Generate maximum time in timespec. */
        tm_max.tv_sec = (-1) & ~((time_t)1 << ((sizeof(tm_max.tv_sec) * 8) - 1));
        tm_max.tv_nsec = (-1) & ~((long)1 << ((sizeof(tm_max.tv_nsec) * 8) - 1));

        /* set log level */
        if (dflag > 1)
                log_upto = LOG_DEBUG;
        else if (dflag > 0)
                log_upto = LOG_INFO;
        else
                log_upto = LOG_NOTICE;

        if (managedconf_script != NULL && *managedconf_script != '/')
                errx(1, "configuration script (%s) must be an absolute path",
                    managedconf_script);
        if (otherconf_script != NULL && *otherconf_script != '/')
                errx(1, "configuration script (%s) must be an absolute path",
                    otherconf_script);
        if (alwaysconf_script != NULL && *alwaysconf_script != '/')
                errx(1, "configuration script (%s) must be an absolute path",
                    alwaysconf_script);
        if (*resolvconf_script != '/')
                errx(1, "configuration script (%s) must be an absolute path",
                    resolvconf_script);

        if (!fflag) {
                pfh = pidfile_open(pidfilepath, 0644, NULL);
                if (pfh == NULL)
                        errx(1, "failed to open pidfile: %s", strerror(errno));
                if (daemon(0, 0) != 0)
                        errx(1, "failed to daemonize");
        }

        if ((error = init_capabilities()) != 0)
                err(1, "failed to initialize capabilities");

        if (!fflag) {
                cap_openlog(capsyslog, progname, LOG_NDELAY | LOG_PID,
                    LOG_DAEMON);
                if (log_upto >= 0)
                        (void)cap_setlogmask(capsyslog, LOG_UPTO(log_upto));
                (void)signal(SIGTERM, set_exit);
                (void)signal(SIGINT, set_exit);
                (void)signal(SIGUSR1, set_dumpfile);
                dumpfp = rtsold_init_dumpfile(RTSOL_DUMPFILE);
        } else
                dumpfp = NULL;

        kq = kqueue();
        if (kq < 0) {
                warnmsg(LOG_ERR, __func__, "failed to create a kqueue: %s",
                    strerror(errno));
                exit(1);
        }

        /* Open global sockets and register for read events. */
        if ((rtsock = rtsock_open()) < 0) {
                warnmsg(LOG_ERR, __func__, "failed to open routing socket");
                exit(1);
        }
        if ((rcvsock = recvsockopen()) < 0) {
                warnmsg(LOG_ERR, __func__, "failed to open receive socket");
                exit(1);
        }
        EV_SET(&events[0], rtsock, EVFILT_READ, EV_ADD, 0, 0, NULL);
        EV_SET(&events[1], rcvsock, EVFILT_READ, EV_ADD, 0, 0, NULL);
        if (kevent(kq, events, 2, NULL, 0, NULL) < 0) {
                warnmsg(LOG_ERR, __func__, "kevent(): %s", strerror(errno));
                exit(1);
        }

        /* Probe network interfaces and set up tracking info. */
        if (ifinit() != 0) {
                warnmsg(LOG_ERR, __func__, "failed to initialize interfaces");
                exit(1);
        }
        if (aflag)
                argv = autoifprobe();
        while (argv && *argv) {
                if (ifconfig(*argv)) {
                        warnmsg(LOG_ERR, __func__,
                            "failed to initialize %s", *argv);
                        exit(1);
                }
                argv++;
        }

        /* Write to our pidfile. */
        if (pfh != NULL && pidfile_write(pfh) != 0) {
                warnmsg(LOG_ERR, __func__,
                    "failed to open pidfile: %s", strerror(errno));
                exit(1);
        }

        /* Enter capability mode. */
        caph_cache_catpages();
        if (caph_enter_casper() != 0) {
                warnmsg(LOG_ERR, __func__, "caph_enter(): %s", strerror(errno));
                exit(1);
        }

        for (;;) {
                if (do_exit) {
                        /* Handle SIGTERM, SIGINT. */
                        if (pfh != NULL)
                                pidfile_remove(pfh);
                        break;
                }
                if (do_dump) {
                        /* Handle SIGUSR1. */
                        do_dump = 0;
                        if (dumpfp != NULL)
                                rtsold_dump(dumpfp);
                }

                timeout = rtsol_check_timer();

                if (once) {
                        /* if we have no timeout, we are done (or failed) */
                        if (timeout == NULL)
                                break;

                        /* if all interfaces have got RA packet, we are done */
                        TAILQ_FOREACH(ifi, &ifinfo_head, ifi_next) {
                                if (ifi->state != IFS_DOWN && ifi->racnt == 0)
                                        break;
                        }
                        if (ifi == NULL)
                                break;
                }

                error = kevent(kq, NULL, 0, &events[0], 1, timeout);
                if (error < 1) {
                        if (error < 0 && errno != EINTR)
                                warnmsg(LOG_ERR, __func__, "kevent(): %s",
                                    strerror(errno));
                        continue;
                }

                if (events[0].ident == (uintptr_t)rtsock)
                        rtsock_input(rtsock);
                else
                        rtsol_input(rcvsock);
        }

        return (0);
}

static int
init_capabilities(void)
{
#ifdef WITH_CASPER
        const char *const scripts[] =
            { resolvconf_script, managedconf_script, otherconf_script,
            alwaysconf_script };
        cap_channel_t *capcasper;
        nvlist_t *limits;

        capcasper = cap_init();
        if (capcasper == NULL)
                return (-1);

        capllflags = cap_service_open(capcasper, "rtsold.llflags");
        if (capllflags == NULL)
                return (-1);

        capscript = cap_service_open(capcasper, "rtsold.script");
        if (capscript == NULL)
                return (-1);
        limits = nvlist_create(0);
        for (size_t i = 0; i < nitems(scripts); i++)
                if (scripts[i] != NULL)
                        nvlist_append_string_array(limits, "scripts",
                            scripts[i]);
        if (cap_limit_set(capscript, limits) != 0)
                return (-1);

        capsendmsg = cap_service_open(capcasper, "rtsold.sendmsg");
        if (capsendmsg == NULL)
                return (-1);

        if (!fflag) {
                capsyslog = cap_service_open(capcasper, "system.syslog");
                if (capsyslog == NULL)
                        return (-1);
        }

        cap_close(capcasper);
#endif /* WITH_CASPER */
        return (0);
}

static int
ifconfig(char *ifname)
{
        struct ifinfo *ifi;
        struct sockaddr_dl *sdl;
        int flags;

        ifi = NULL;
        if ((sdl = if_nametosdl(ifname)) == NULL) {
                warnmsg(LOG_ERR, __func__,
                    "failed to get link layer information for %s", ifname);
                goto bad;
        }
        if (find_ifinfo(sdl->sdl_index)) {
                warnmsg(LOG_ERR, __func__,
                    "interface %s was already configured", ifname);
                goto bad;
        }

        if (Fflag) {
                struct in6_ndireq nd;
                int s;

                if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
                        warnmsg(LOG_ERR, __func__, "socket() failed.");
                        goto bad;
                }
                memset(&nd, 0, sizeof(nd));
                strlcpy(nd.ifname, ifname, sizeof(nd.ifname));
                if (ioctl(s, SIOCGIFINFO_IN6, (caddr_t)&nd) < 0) {
                        warnmsg(LOG_ERR, __func__,
                            "cannot get accept_rtadv flag");
                        (void)close(s);
                        goto bad;
                }
                nd.ndi.flags |= ND6_IFF_ACCEPT_RTADV;
                if (ioctl(s, SIOCSIFINFO_IN6, (caddr_t)&nd) < 0) {
                        warnmsg(LOG_ERR, __func__,
                            "cannot set accept_rtadv flag");
                        (void)close(s);
                        goto bad;
                }
                (void)close(s);
        }

        if ((ifi = malloc(sizeof(*ifi))) == NULL) {
                warnmsg(LOG_ERR, __func__, "memory allocation failed");
                goto bad;
        }
        memset(ifi, 0, sizeof(*ifi));
        ifi->sdl = sdl;
        ifi->ifi_rdnss = IFI_DNSOPT_STATE_NOINFO;
        ifi->ifi_dnssl = IFI_DNSOPT_STATE_NOINFO;
        TAILQ_INIT(&ifi->ifi_rainfo);
        strlcpy(ifi->ifname, ifname, sizeof(ifi->ifname));

        /* construct a router solicitation message */
        if (make_packet(ifi))
                goto bad;

        /* set link ID of this interface. */
#ifdef HAVE_SCOPELIB
        if (inet_zoneid(AF_INET6, 2, ifname, &ifi->linkid))
                goto bad;
#else
        /* XXX: assume interface IDs as link IDs */
        ifi->linkid = ifi->sdl->sdl_index;
#endif

        /*
         * check if the interface is available.
         * also check if SIOCGIFMEDIA ioctl is OK on the interface.
         */
        ifi->mediareqok = 1;
        ifi->active = interface_status(ifi);
        if (!ifi->mediareqok) {
                /*
                 * probe routers periodically even if the link status
                 * does not change.
                 */
                ifi->probeinterval = PROBE_INTERVAL;
        }

        /* activate interface: interface_up returns 0 on success */
        flags = interface_up(ifi->ifname);
        if (flags == 0)
                ifi->state = IFS_DELAY;
        else if (flags == IFS_TENTATIVE)
                ifi->state = IFS_TENTATIVE;
        else
                ifi->state = IFS_DOWN;

        rtsol_timer_update(ifi);

        TAILQ_INSERT_TAIL(&ifinfo_head, ifi, ifi_next);
        return (0);

bad:
        free(sdl);
        free(ifi);
        return (-1);
}

struct rainfo *
find_rainfo(struct ifinfo *ifi, struct sockaddr_in6 *sin6)
{
        struct rainfo *rai;

        TAILQ_FOREACH(rai, &ifi->ifi_rainfo, rai_next)
                if (memcmp(&rai->rai_saddr.sin6_addr, &sin6->sin6_addr,
                    sizeof(rai->rai_saddr.sin6_addr)) == 0)
                        return (rai);

        return (NULL);
}

struct ifinfo *
find_ifinfo(int ifindex)
{
        struct ifinfo *ifi;

        TAILQ_FOREACH(ifi, &ifinfo_head, ifi_next) {
                if (ifi->sdl->sdl_index == ifindex)
                        return (ifi);
        }
        return (NULL);
}

static int
make_packet(struct ifinfo *ifi)
{
        size_t packlen = sizeof(struct nd_router_solicit), lladdroptlen = 0;
        struct nd_router_solicit *rs;
        char *buf;

        if ((lladdroptlen = lladdropt_length(ifi->sdl)) == 0) {
                warnmsg(LOG_INFO, __func__,
                    "link-layer address option has null length"
                    " on %s. Treat as not included.", ifi->ifname);
        }
        packlen += lladdroptlen;
        ifi->rs_datalen = packlen;

        /* allocate buffer */
        if ((buf = malloc(packlen)) == NULL) {
                warnmsg(LOG_ERR, __func__,
                    "memory allocation failed for %s", ifi->ifname);
                return (-1);
        }
        ifi->rs_data = buf;

        /* fill in the message */
        rs = (struct nd_router_solicit *)buf;
        rs->nd_rs_type = ND_ROUTER_SOLICIT;
        rs->nd_rs_code = 0;
        rs->nd_rs_cksum = 0;
        rs->nd_rs_reserved = 0;
        buf += sizeof(*rs);

        /* fill in source link-layer address option */
        if (lladdroptlen)
                lladdropt_fill(ifi->sdl, (struct nd_opt_hdr *)buf);

        return (0);
}

static struct timespec *
rtsol_check_timer(void)
{
        static struct timespec returnval;
        struct timespec now, rtsol_timer;
        struct ifinfo *ifi;
        struct rainfo *rai;
        struct ra_opt *rao, *raotmp;
        int error, flags;

        clock_gettime(CLOCK_MONOTONIC_FAST, &now);

        rtsol_timer = tm_max;

        TAILQ_FOREACH(ifi, &ifinfo_head, ifi_next) {
                if (TS_CMP(&ifi->expire, &now, <=)) {
                        warnmsg(LOG_DEBUG, __func__, "timer expiration on %s, "
                            "state = %d", ifi->ifname, ifi->state);

                        while((rai = TAILQ_FIRST(&ifi->ifi_rainfo)) != NULL) {
                                /* Remove all RA options. */
                                TAILQ_REMOVE(&ifi->ifi_rainfo, rai, rai_next);
                                while ((rao = TAILQ_FIRST(&rai->rai_ra_opt)) !=
                                    NULL) {
                                        TAILQ_REMOVE(&rai->rai_ra_opt, rao,
                                            rao_next);
                                        if (rao->rao_msg != NULL)
                                                free(rao->rao_msg);
                                        free(rao);
                                }
                                free(rai);
                        }
                        switch (ifi->state) {
                        case IFS_DOWN:
                        case IFS_TENTATIVE:
                                /* interface_up returns 0 on success */
                                flags = interface_up(ifi->ifname);
                                if (flags == 0)
                                        ifi->state = IFS_DELAY;
                                else if (flags == IFS_TENTATIVE)
                                        ifi->state = IFS_TENTATIVE;
                                else
                                        ifi->state = IFS_DOWN;
                                break;
                        case IFS_IDLE:
                        {
                                int oldstatus = ifi->active;
                                int probe = 0;

                                ifi->active = interface_status(ifi);

                                if (oldstatus != ifi->active) {
                                        warnmsg(LOG_DEBUG, __func__,
                                            "%s status is changed"
                                            " from %d to %d",
                                            ifi->ifname,
                                            oldstatus, ifi->active);
                                        probe = 1;
                                        ifi->state = IFS_DELAY;
                                } else if (ifi->probeinterval &&
                                    (ifi->probetimer -=
                                    ifi->timer.tv_sec) <= 0) {
                                        /* probe timer expired */
                                        ifi->probetimer =
                                            ifi->probeinterval;
                                        probe = 1;
                                        ifi->state = IFS_PROBE;
                                }

                                /*
                                 * If we need a probe, clear the previous
                                 * status wrt the "managed/other" configuration.
                                 */
                                if (probe) {
                                        ifi->managedconfig = 0;
                                        ifi->otherconfig = 0;
                                        ifi->alwaysconfig = 0;
                                }
                                if (probe && mobile_node) {
                                        error = cap_probe_defrouters(capsendmsg,
                                            ifi);
                                        if (error != 0)
                                                warnmsg(LOG_DEBUG, __func__,
                                            "failed to probe routers: %d",
                                                    error);
                                }
                                break;
                        }
                        case IFS_DELAY:
                                ifi->state = IFS_PROBE;
                                (void)cap_rssend(capsendmsg, ifi);
                                break;
                        case IFS_PROBE:
                                if (ifi->probes < MAX_RTR_SOLICITATIONS)
                                        (void)cap_rssend(capsendmsg, ifi);
                                else {
                                        warnmsg(LOG_INFO, __func__,
                                            "No answer after sending %d RSs",
                                            ifi->probes);
                                        ifi->probes = 0;
                                        ifi->state = IFS_IDLE;
                                }
                                break;
                        }
                        rtsol_timer_update(ifi);
                } else {
                        /* Expiration check for RA options. */
                        int expire = 0;

                        TAILQ_FOREACH(rai, &ifi->ifi_rainfo, rai_next) {
                                TAILQ_FOREACH_SAFE(rao, &rai->rai_ra_opt,
                                    rao_next, raotmp) {
                                        warnmsg(LOG_DEBUG, __func__,
                                            "RA expiration timer: "
                                            "type=%d, msg=%s, expire=%s",
                                            rao->rao_type, (char *)rao->rao_msg,
                                                sec2str(&rao->rao_expire));
                                        if (TS_CMP(&now, &rao->rao_expire,
                                            >=)) {
                                                warnmsg(LOG_DEBUG, __func__,
                                                    "RA expiration timer: "
                                                    "expired.");
                                                TAILQ_REMOVE(&rai->rai_ra_opt,
                                                    rao, rao_next);
                                                if (rao->rao_msg != NULL)
                                                        free(rao->rao_msg);
                                                free(rao);
                                                expire = 1;
                                        }
                                }
                        }
                        if (expire)
                                ra_opt_handler(ifi);
                }
                if (TS_CMP(&ifi->expire, &rtsol_timer, <))
                        rtsol_timer = ifi->expire;
        }

        if (TS_CMP(&rtsol_timer, &tm_max, ==)) {
                warnmsg(LOG_DEBUG, __func__, "there is no timer");
                return (NULL);
        } else if (TS_CMP(&rtsol_timer, &now, <))
                /* this may occur when the interval is too small */
                returnval.tv_sec = returnval.tv_nsec = 0;
        else
                TS_SUB(&rtsol_timer, &now, &returnval);

        now.tv_sec += returnval.tv_sec;
        now.tv_nsec += returnval.tv_nsec;
        warnmsg(LOG_DEBUG, __func__, "New timer is %s",
            sec2str(&now));

        return (&returnval);
}

void
rtsol_timer_update(struct ifinfo *ifi)
{
#define MILLION 1000000
#define DADRETRY 10             /* XXX: adhoc */
        long interval;
        struct timespec now;

        bzero(&ifi->timer, sizeof(ifi->timer));

        switch (ifi->state) {
        case IFS_DOWN:
        case IFS_TENTATIVE:
                if (++ifi->dadcount > DADRETRY) {
                        ifi->dadcount = 0;
                        ifi->timer.tv_sec = PROBE_INTERVAL;
                } else
                        ifi->timer.tv_sec = 1;
                break;
        case IFS_IDLE:
                if (mobile_node)
                        /* XXX should be configurable */
                        ifi->timer.tv_sec = 3;
                else
                        ifi->timer = tm_max;    /* stop timer(valid?) */
                break;
        case IFS_DELAY:
                if (no_solicitation_delay)
                        interval = 0;
                else
                        interval = arc4random_uniform(MAX_RTR_SOLICITATION_DELAY * MILLION);
                ifi->timer.tv_sec = interval / MILLION;
                ifi->timer.tv_nsec = (interval % MILLION) * 1000;
                break;
        case IFS_PROBE:
                if (ifi->probes < MAX_RTR_SOLICITATIONS)
                        ifi->timer.tv_sec = RTR_SOLICITATION_INTERVAL;
                else
                        /*
                         * After sending MAX_RTR_SOLICITATIONS solicitations,
                         * we're just waiting for possible replies; there
                         * will be no more solicitation.  Thus, we change
                         * the timer value to MAX_RTR_SOLICITATION_DELAY based
                         * on RFC 2461, Section 6.3.7.
                         */
                        ifi->timer.tv_sec = MAX_RTR_SOLICITATION_DELAY;
                break;
        default:
                warnmsg(LOG_ERR, __func__,
                    "illegal interface state(%d) on %s",
                    ifi->state, ifi->ifname);
                return;
        }

        /* reset the timer */
        if (TS_CMP(&ifi->timer, &tm_max, ==)) {
                ifi->expire = tm_max;
                warnmsg(LOG_DEBUG, __func__,
                    "stop timer for %s", ifi->ifname);
        } else {
                clock_gettime(CLOCK_MONOTONIC_FAST, &now);
                TS_ADD(&now, &ifi->timer, &ifi->expire);

                now.tv_sec += ifi->timer.tv_sec;
                now.tv_nsec += ifi->timer.tv_nsec;
                warnmsg(LOG_DEBUG, __func__, "set timer for %s to %s",
                    ifi->ifname, sec2str(&now));
        }

#undef MILLION
}

static void
set_dumpfile(int sig __unused)
{

        do_dump = 1;
}

static void
set_exit(int sig __unused)
{

        do_exit = 1;
}

static void
usage(const char *progname)
{

        if (strcmp(progname, "rtsold") == 0) {
                fprintf(stderr, "usage: rtsold [-dDfFimu1] [-O script-name] "
                    "[-M script-name ] [-A script-name ] "
                    "[-p pidfile] [-R script-name] interface ...\n");
                fprintf(stderr, "usage: rtsold [-dDfFimu1] [-O script-name] "
                    "[-M script-name ] [-A script-name ] "
                    "[-p pidfile] [-R script-name] -a\n");
        } else {
                fprintf(stderr, "usage: rtsol [-dDFiu] [-O script-name] "
                    "[-M script-name ] [-A script-name ] "
                    "[-R script-name] interface ...\n");
                fprintf(stderr, "usage: rtsol [-dDFiu] [-O script-name] "
                    "[-M script-name ] [-A script-name ] "
                    "[-R script-name] -a\n");
        }
        exit(1);
}

void
warnmsg(int priority, const char *func, const char *msg, ...)
{
        va_list ap;
        char buf[BUFSIZ];

        va_start(ap, msg);
        if (fflag) {
                if (priority <= log_upto)
                        vwarnx(msg, ap);
        } else {
                snprintf(buf, sizeof(buf), "<%s> %s", func, msg);
                msg = buf;
                cap_vsyslog(capsyslog, priority, msg, ap);
        }
        va_end(ap);
}

/*
 * return a list of interfaces which is suitable to sending an RS.
 */
static char **
autoifprobe(void)
{
        static char **argv = NULL;
        static int n = 0;
        char **a;
        int s = 0, i, found;
        struct ifaddrs *ifap, *ifa;
        struct in6_ndireq nd;

        /* initialize */
        while (n--)
                free(argv[n]);
        if (argv) {
                free(argv);
                argv = NULL;
        }
        n = 0;

        if (getifaddrs(&ifap) != 0)
                return (NULL);

        if (!Fflag && (s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
                warnmsg(LOG_ERR, __func__, "socket");
                exit(1);
        }

        /* find an ethernet */
        for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
                if ((ifa->ifa_flags & IFF_UP) == 0)
                        continue;
                if ((ifa->ifa_flags & IFF_LOOPBACK) != 0)
                        continue;
                if ((ifa->ifa_flags & IFF_MULTICAST) == 0)
                        continue;

                if (ifa->ifa_addr->sa_family != AF_INET6)
                        continue;

                found = 0;
                for (i = 0; i < n; i++) {
                        if (strcmp(argv[i], ifa->ifa_name) == 0) {
                                found++;
                                break;
                        }
                }
                if (found)
                        continue;

                /*
                 * Skip the interfaces which IPv6 and/or accepting RA
                 * is disabled.
                 */
                if (!Fflag) {
                        memset(&nd, 0, sizeof(nd));
                        strlcpy(nd.ifname, ifa->ifa_name, sizeof(nd.ifname));
                        if (ioctl(s, SIOCGIFINFO_IN6, (caddr_t)&nd) < 0) {
                                warnmsg(LOG_ERR, __func__,
                                        "ioctl(SIOCGIFINFO_IN6)");
                                exit(1);
                        }
                        if ((nd.ndi.flags & ND6_IFF_IFDISABLED))
                                continue;
                        if (!(nd.ndi.flags & ND6_IFF_ACCEPT_RTADV))
                                continue;
                }

                /* if we find multiple candidates, just warn. */
                if (n != 0 && dflag > 1)
                        warnmsg(LOG_WARNING, __func__,
                                "multiple interfaces found");

                a = realloc(argv, (n + 1) * sizeof(char *));
                if (a == NULL) {
                        warnmsg(LOG_ERR, __func__, "realloc");
                        exit(1);
                }
                argv = a;
                argv[n] = strdup(ifa->ifa_name);
                if (!argv[n]) {
                        warnmsg(LOG_ERR, __func__, "malloc");
                        exit(1);
                }
                n++;
        }

        if (n) {
                a = realloc(argv, (n + 1) * sizeof(char *));
                if (a == NULL) {
                        warnmsg(LOG_ERR, __func__, "realloc");
                        exit(1);
                }
                argv = a;
                argv[n] = NULL;

                if (dflag > 0) {
                        for (i = 0; i < n; i++)
                                warnmsg(LOG_WARNING, __func__, "probing %s",
                                        argv[i]);
                }
        }
        if (!Fflag)
                close(s);
        freeifaddrs(ifap);
        return (argv);
}