/*      $NetBSD: arp.c,v 1.68 2020/09/15 11:14:16 roy Exp $ */

/*
 * Copyright (c) 1984, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Sun Microsystems, Inc.
 *
 * 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 University 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 REGENTS 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 REGENTS 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/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1984, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)arp.c       8.3 (Berkeley) 4/28/95";
#else
__RCSID("$NetBSD: arp.c,v 1.68 2020/09/15 11:14:16 roy Exp $");
#endif
#endif /* not lint */

/*
 * arp - display, set, and delete arp table entries
 */

#include <sys/param.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/ioctl.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_ether.h>
#include <net/if_types.h>
#include <net/nd.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/if_inarp.h>
#include <arpa/inet.h>

#include <err.h>
#include <errno.h>
#include <netdb.h>
#include <nlist.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ifaddrs.h>

#include "prog_ops.h"

static int is_llinfo(const struct sockaddr_dl *, int);
static int delete_one(struct rt_msghdr *);
static void dump(uint32_t);
static void delete(const char *, const char *);
static void sdl_print(const struct sockaddr_dl *);
static int getifname(u_int16_t, char *, size_t);
static int atosdl(const char *, struct sockaddr_dl *);
static int file(const char *);
static void get(const char *);
static int getinetaddr(const char *, struct in_addr *);
static int getsocket(void);
static int getetheraddr(struct in_addr, struct sockaddr_dl *);
static struct rt_msghdr * rtmsg(const int, const int,  struct rt_msghdr *,
        const struct sockaddr_inarp *, const struct sockaddr_dl *);
static struct in_nbrinfo * getnbrinfo(const char *, struct in_addr *);
static const char * sec2str(time_t);
static int set(int, char **);
static void usage(void) __dead;

static int aflag, nflag, vflag;
static struct sockaddr_in so_mask = {
        .sin_len = 8,
        .sin_addr = {
                .s_addr = 0xffffffff
        }
};
static struct sockaddr_inarp blank_sin = {
        .sin_len = sizeof(blank_sin),
        .sin_family = AF_INET
};
static struct sockaddr_dl blank_sdl = {
        .sdl_len = sizeof(blank_sdl),
        .sdl_family = AF_LINK
};

static int expire_time, flags, export_only, doing_proxy, found_entry;

int
main(int argc, char **argv)
{
        int ch;
        int op = 0;

        setprogname(argv[0]);

        while ((ch = getopt(argc, argv, "andsfv")) != -1)
                switch((char)ch) {
                case 'a':
                        aflag = 1;
                        break;
                case 'd':
                case 's':
                case 'f':
                        if (op)
                                usage();
                        op = ch;
                        break;
                case 'n':
                        nflag = 1;
                        break;
                case 'v':
                        vflag = 1;
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (!op && aflag)
                op = 'a';

        if (prog_init && prog_init() == -1)
                err(1, "init failed");

        switch((char)op) {
        case 'a':
                dump(0);
                break;
        case 'd':
                if (aflag && argc == 0)
                        delete(NULL, NULL);
                else {
                        if (aflag || argc < 1 || argc > 2)
                                usage();
                        delete(argv[0], argv[1]);
                }
                break;
        case 's':
                if (argc < 2 || argc > 7)
                        usage();
                return (set(argc, argv) ? 1 : 0);
        case 'f':
                if (argc != 1)
                        usage();
                return (file(argv[0]));
        default:
                if (argc != 1)
                        usage();
                get(argv[0]);
                break;
        }
        return (0);
}

/*
 * Process a file to set standard arp entries
 */
static int
file(const char *name)
{
        char *line, *argv[5];
        int i, retval;
        FILE *fp;

        if (!strcmp(name, "-")) {
                fp = stdin;
        } else {
                fp = fopen(name, "r");
                if (fp == NULL) {
                        err(1, "Cannot open %s", name);
                }
        }
        retval = 0;
        for (; (line = fparseln(fp, NULL, NULL, NULL, 0)) != NULL; free(line)) {
                char **ap, *inputstring;

                inputstring = line;
                for (ap = argv; ap < &argv[sizeof(argv) / sizeof(argv[0])] &&
                    (*ap = stresep(&inputstring, " \t", '\\')) != NULL;) {
                        if (**ap != '\0')
                                ap++;
                }
                i = ap - argv;
                if (i < 2) {
                        warnx("bad line: %s", line);
                        retval = 1;
                        continue;
                }
                if (set(i, argv))
                        retval = 1;
        }
        if (fp != stdin)
                (void)fclose(fp);
        return retval;
}

static int
getsocket(void)
{
        int s;
        s = prog_socket(PF_ROUTE, SOCK_RAW, 0);
        if (s < 0)
                err(1, "socket");
        return s;
}

static int
getlink(const char *name, struct sockaddr_dl *sdl)
{
        struct ifaddrs *ifap, *ifa;

        if (getifaddrs(&ifap) != 0) {
                warn("getifaddrs");
                return 0;
        }

        for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
                if (ifa->ifa_addr->sa_family != AF_LINK)
                        continue;
                if (strcmp(ifa->ifa_name, name) != 0)
                        continue;
                memcpy(sdl, ifa->ifa_addr, sizeof(*sdl));
                freeifaddrs(ifap);
                return 1;
        }
        freeifaddrs(ifap);
        return 0;
}

/*
 * Set an individual arp entry
 */
static int
set(int argc, char **argv)
{
        struct sockaddr_inarp *sina;
        struct sockaddr_dl *sdl = NULL;
        struct rt_msghdr *rtm;
        char *host = argv[0], *eaddr;
        struct sockaddr_inarp sin_m = blank_sin; /* struct copy */
        struct sockaddr_dl sdl_m = blank_sdl; /* struct copy */
        int s;

        eaddr = argv[1];

        s = getsocket();
        argc -= 2;
        argv += 2;

        if (getinetaddr(host, &sin_m.sin_addr) == -1) {
                prog_close(s);
                return (1);
        }
        if (strcmp(eaddr, "auto") != 0 && atosdl(eaddr, &sdl_m))
                warnx("invalid link-level address '%s'", eaddr);
        doing_proxy = flags = export_only = expire_time = 0;
        for (; argc-- > 0; argv++) {
                if (strncmp(argv[0], "temp", 4) == 0) {
                        struct timeval timev;
                        (void)gettimeofday(&timev, 0);
                        expire_time = timev.tv_sec + 20 * 60;
                }
                else if (strncmp(argv[0], "pub", 3) == 0) {
                        flags |= RTF_ANNOUNCE;
                        doing_proxy = 1;
                        if (argc && strncmp(argv[1], "pro", 3) == 0) {
                                export_only = 1;
                                argc--; argv++;
                        }
                } else if (strncmp(argv[0], "trail", 5) == 0) {
                        warnx("%s: Sending trailers is no longer supported",
                            host);
                } else if (strcmp(argv[0], "ifscope") == 0) {
                        if (argc == 0) {
                                warnx("missing interface for ifscope");
                                continue;
                        }
                        argc--;
                        argv++;
                        if (!getlink(argv[0], &sdl_m))
                                warnx("cannot get link address for %s", argv[0]);
                }

        }
        if (doing_proxy && strcmp(eaddr, "auto") == 0) {
                if (getetheraddr(sin_m.sin_addr, &sdl_m) == -1) {
                        prog_close(s);
                        return 1;
                }
        }
tryagain:
        rtm = rtmsg(s, RTM_GET, NULL, &sin_m, &sdl_m);
        if (rtm == NULL) {
                warn("%s", host);
                prog_close(s);
                return (1);
        }
        sina = (struct sockaddr_inarp *)(void *)(rtm + 1);
        sdl = (struct sockaddr_dl *)(void *)(RT_ROUNDUP(sina->sin_len) +
            (char *)(void *)sina);
        if (sina->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
                if (is_llinfo(sdl, rtm->rtm_flags))
                        goto overwrite;
                if (doing_proxy == 0) {
                        warnx("set: can only proxy for %s", host);
                        prog_close(s);
                        return (1);
                }
                if (sin_m.sin_other & SIN_PROXY) {
                        warnx("set: proxy entry exists for non 802 device");
                        prog_close(s);
                        return (1);
                }
                sin_m.sin_other = SIN_PROXY;
                export_only = 1;
                goto tryagain;
        }
overwrite:
        if (sdl->sdl_family != AF_LINK) {
                warnx("cannot intuit interface index and type for %s",
                    host);
                prog_close(s);
                return (1);
        }
        sdl_m.sdl_type = sdl->sdl_type;
        sdl_m.sdl_index = sdl->sdl_index;
        sin_m.sin_other = 0;
        if (doing_proxy && export_only)
                sin_m.sin_other = SIN_PROXY;
        rtm = rtmsg(s, RTM_ADD, NULL, &sin_m, &sdl_m);
        if (vflag)
                (void)printf("%s (%s) added\n", host, eaddr);
        prog_close(s);
        return (rtm == NULL) ? 1 : 0;
}

/*
 * Display an individual arp entry
 */
static void
get(const char *host)
{
        struct sockaddr_inarp sin = blank_sin; /* struct copy */

        if (getinetaddr(host, &sin.sin_addr) == -1)
                exit(1);
        dump(sin.sin_addr.s_addr);
        if (found_entry == 0)
                errx(1, "%s (%s) -- no entry", host, inet_ntoa(sin.sin_addr));
}


static int
is_llinfo(const struct sockaddr_dl *sdl, int rtflags)
{
        if (sdl->sdl_family != AF_LINK ||
            (rtflags & (RTF_LLDATA|RTF_GATEWAY)) != RTF_LLDATA)
                return 0;

        switch (sdl->sdl_type) {
        case IFT_ETHER:
        case IFT_FDDI:
        case IFT_ISO88023:
        case IFT_ISO88024:
        case IFT_ISO88025:
        case IFT_ARCNET:
                return 1;
        default:
                return 0;
        }
}

/*
 * Delete an arp entry
 */
int
delete_one(struct rt_msghdr *rtm)
{
        struct sockaddr_inarp *sina;
        struct sockaddr_dl *sdl;
        int s;

        s = getsocket();
        sina = (struct sockaddr_inarp *)(void *)(rtm + 1);
        sdl = (struct sockaddr_dl *)(void *)(RT_ROUNDUP(sina->sin_len) +
            (char *)(void *)sina);
        if (sdl->sdl_family != AF_LINK) {
                prog_close(s);
                return (1);
        }
        rtm = rtmsg(s, RTM_DELETE, rtm, sina, sdl);
        prog_close(s);
        if (rtm == NULL)
                return (1);
        return (0);
}

/*
 * Dump the entire arp table
 */
void
dump(uint32_t addr)
{
        int mib[6];
        size_t needed;
        char ifname[IFNAMSIZ];
        char *lim, *buf, *next;
        const char *host;
        struct rt_msghdr *rtm;
        struct sockaddr_inarp *sina;
        struct sockaddr_dl *sdl;
        struct hostent *hp;
        struct timeval tim;
        struct in_nbrinfo *nbi;

        mib[0] = CTL_NET;
        mib[1] = PF_ROUTE;
        mib[2] = 0;
        mib[3] = AF_INET;
        mib[4] = NET_RT_FLAGS;
        mib[5] = 0;
        if (prog_sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
                err(1, "route-sysctl-estimate");
        if (needed == 0)
                return;
        if ((buf = malloc(needed)) == NULL)
                err(1, "malloc");
        if (prog_sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
                err(1, "actual retrieval of routing table");
        lim = buf + needed;
        for (next = buf; next < lim; next += rtm->rtm_msglen) {
                rtm = (struct rt_msghdr *)(void *)next;
                sina = (struct sockaddr_inarp *)(void *)(rtm + 1);
                sdl = (struct sockaddr_dl *)(void *)
                    (RT_ROUNDUP(sina->sin_len) + (char *)(void *)sina);
                if (addr) {
                        if (addr != sina->sin_addr.s_addr)
                                continue;
                        found_entry = 1;
                }
                if (nflag == 0)
                        hp = gethostbyaddr((const char *)(void *)
                            &(sina->sin_addr),
                            sizeof sina->sin_addr, AF_INET);
                else
                        hp = NULL;

                host = hp ? hp->h_name : "?";

                (void)printf("%s (%s) at ", host, inet_ntoa(sina->sin_addr));
                if (sdl->sdl_alen)
                        sdl_print(sdl);
                else
                        (void)printf("(incomplete)");

                if (sdl->sdl_index) {
                        if (getifname(sdl->sdl_index, ifname, sizeof(ifname)) == 0)
                                (void)printf(" on %s", ifname);
                }

                if (sina->sin_other & SIN_PROXY)
                        (void)printf(" published (proxy only)");
                if (rtm->rtm_addrs & RTA_NETMASK) {
                        sina = (struct sockaddr_inarp *)(void *)
                            (RT_ROUNDUP(sdl->sdl_len) + (char *)(void *)sdl);
                        if (sina->sin_addr.s_addr == 0xffffffff)
                                (void)printf(" published");
                        if (sina->sin_len != 8)
                                (void)printf("(weird)");
                }

                if (sdl->sdl_index == 0)
                        goto done;
                (void)gettimeofday(&tim, 0);
                nbi = getnbrinfo(ifname, &sina->sin_addr);
                if (nbi != NULL) {
                        if (nbi->expire > tim.tv_sec) {
                                (void)printf(" %s",
                                    sec2str(nbi->expire - tim.tv_sec));
                        } else if (nbi->expire == 0)
                                (void)printf(" %s", "permanent");
                        else
                                (void)printf(" %s", "expired");

                        switch (nbi->state) {
                        case ND_LLINFO_NOSTATE:
                                (void)printf(" N");
                                break;
                        case ND_LLINFO_WAITDELETE:
                                (void)printf(" W");
                                break;
                        case ND_LLINFO_INCOMPLETE:
                                (void)printf(" I");
                                break;
                        case ND_LLINFO_REACHABLE:
                                (void)printf(" R");
                                break;
                        case ND_LLINFO_STALE:
                                (void)printf(" S");
                                break;
                        case ND_LLINFO_DELAY:
                                (void)printf(" D");
                                break;
                        case ND_LLINFO_PROBE:
                                (void)printf(" P");
                                break;
                        case ND_LLINFO_UNREACHABLE:
                                (void)printf(" U");
                                break;
                        default:
                                (void)printf(" ?");
                                break;
                        }
                }

done:
                (void)printf("\n");
        }
        free(buf);
}

/*
 * Delete the entire arp table
 */
void
delete(const char *host, const char *info)
{
        int mib[6];
        char addr[sizeof("000.000.000.000\0")];
        size_t needed;
        char *lim, *buf, *next;
        struct rt_msghdr *rtm;
        struct sockaddr_inarp *sina;
        struct sockaddr_inarp sin_m = blank_sin; /* struct copy */
        bool found = false;

        if (host != NULL) {
                int ret = getinetaddr(host, &sin_m.sin_addr);
                if (ret == -1)
                        return;
        }
        if (info && strncmp(info, "pro", 3) == 0)
                sin_m.sin_other = SIN_PROXY;

retry:
        mib[0] = CTL_NET;
        mib[1] = PF_ROUTE;
        mib[2] = 0;
        mib[3] = AF_INET;
        mib[4] = NET_RT_FLAGS;
        mib[5] = RTF_LLDATA;
        if (prog_sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
                err(1, "route-sysctl-estimate");
        if (needed == 0)
                return;
        if ((buf = malloc(needed)) == NULL)
                err(1, "malloc");
        if (prog_sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
                free(buf);
                if (errno == ENOBUFS)
                        goto retry;
                err(1, "actual retrieval of routing table");
        }
        lim = buf + needed;

        for (next = buf; next < lim; next += rtm->rtm_msglen) {
                int ret;
                rtm = (struct rt_msghdr *)(void *)next;
                sina = (struct sockaddr_inarp *)(void *)(rtm + 1);
                if (host != NULL &&
                    sina->sin_addr.s_addr != sin_m.sin_addr.s_addr)
                        continue;
                found = true;
                ret = delete_one(rtm);
                if (vflag && ret == 0) {
                        snprintf(addr, sizeof(addr), "%s",
                            inet_ntoa(sina->sin_addr));
                        (void)printf("%s (%s) deleted\n",
                            host != NULL ? host : addr, addr);
                }
        }
        if (host != NULL && !found)
                warnx("delete: can't locate %s", host);
        free(buf);
}

void
sdl_print(const struct sockaddr_dl *sdl)
{
        char hbuf[NI_MAXHOST];

        if (getnameinfo((const struct sockaddr *)(const void *)sdl,
            (socklen_t)sdl->sdl_len,
            hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0)
                (void)printf("<invalid>");
        else
                (void)printf("%s", hbuf);
}

static int
atosdl(const char *ss, struct sockaddr_dl *sdl)
{
        int i;
        unsigned long b;
        char *endp;
        char *p;
        char *t, *r;

        p = LLADDR(sdl);
        endp = ((char *)(void *)sdl) + sdl->sdl_len;
        i = 0;

        b = strtoul(ss, &t, 16);
        if (b > 255 || t == ss)
                return 1;

        *p++ = (char)b;
        ++i;
        while ((p < endp) && (*t++ == ':')) {
                b = strtoul(t, &r, 16);
                if (b > 255 || r == t)
                        break;
                *p++ = (char)b;
                ++i;
                t = r;
        }
        sdl->sdl_alen = i;

        return 0;
}

static void
usage(void)
{
        const char *progname;

        progname = getprogname();
        (void)fprintf(stderr, "Usage: %s [-n] hostname\n", progname);
        (void)fprintf(stderr, "       %s [-nv] -a\n", progname);
        (void)fprintf(stderr, "       %s [-v] -d [-a|hostname [proxy]]\n",
            progname);
        (void)fprintf(stderr, "       %s -s hostname ether_addr [temp] [pub [proxy]]\n",
            progname);
        (void)fprintf(stderr, "       %s -f filename\n", progname);
        exit(1);
}

static struct rt_msghdr *
rtmsg(const int s, const int cmd, struct rt_msghdr *_rtm,
    const struct sockaddr_inarp *sin, const struct sockaddr_dl *sdl)
{
        static int seq;
        struct rt_msghdr *rtm = _rtm;
        char *cp;
        int l;
        static struct {
                struct  rt_msghdr m_rtm;
                char    m_space[512];
        } m_rtmsg;
        pid_t pid;

        errno = 0;
        if (rtm != NULL) {
                memcpy(&m_rtmsg, rtm, rtm->rtm_msglen);
                rtm = &m_rtmsg.m_rtm;
                goto doit;
        }
        (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg));
        rtm = &m_rtmsg.m_rtm;
        cp = m_rtmsg.m_space;

        rtm->rtm_flags = flags;
        rtm->rtm_version = RTM_VERSION;

        switch (cmd) {
        default:
                errx(1, "internal wrong cmd");
                /*NOTREACHED*/
        case RTM_ADD:
                rtm->rtm_addrs |= RTA_GATEWAY;
                rtm->rtm_rmx.rmx_expire = expire_time;
                rtm->rtm_inits = RTV_EXPIRE;
                rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA);
                if (doing_proxy) {
                        if (!export_only) {
                                rtm->rtm_addrs |= RTA_NETMASK;
                                rtm->rtm_flags &= ~RTF_HOST;
                        }
                }
                rtm->rtm_addrs |= RTA_DST;
                break;
        case RTM_GET:
                rtm->rtm_flags |= RTF_LLDATA;
                rtm->rtm_addrs |= RTA_DST | RTA_GATEWAY;
        }

#define NEXTADDR(w, s) \
        if (rtm->rtm_addrs & (w)) { \
                (void)memcpy(cp, &s, \
                    (size_t)((const struct sockaddr *)&s)->sa_len); \
                RT_ADVANCE(cp, ((const struct sockaddr *)&s)); \
        }

        NEXTADDR(RTA_DST, *sin);
        NEXTADDR(RTA_GATEWAY, *sdl);
        NEXTADDR(RTA_NETMASK, so_mask);

        rtm->rtm_msglen = cp - (char *)(void *)&m_rtmsg;
doit:
        l = rtm->rtm_msglen;
        rtm->rtm_seq = ++seq;
        rtm->rtm_type = cmd;
        if (prog_write(s, &m_rtmsg, (size_t)l) < 0) {
                if (errno != ESRCH || cmd != RTM_DELETE) {
                        warn("writing to routing socket");
                        return NULL;
                }
        }

        pid = prog_getpid();
        do {
                l = prog_read(s, &m_rtmsg, sizeof(m_rtmsg));
        } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
        if (l < 0)
                warn("read from routing socket");
        return rtm;
}

static int
getinetaddr(const char *host, struct in_addr *inap)
{
        struct hostent *hp;

        if (inet_aton(host, inap) == 1)
                return (0);
        if ((hp = gethostbyname(host)) == NULL) {
                warnx("%s: %s", host, hstrerror(h_errno));
                return (-1);
        }
        (void)memcpy(inap, hp->h_addr, sizeof(*inap));
        return (0);
}

static int
getifname(u_int16_t ifindex, char *ifname, size_t l)
{
        int i;
        struct ifaddrs *addr;
        const struct sockaddr_dl *sdl;
        static struct ifaddrs* ifaddrs = NULL;

        if (ifaddrs == NULL) {
                i = getifaddrs(&ifaddrs);
                if (i != 0)
                        err(1, "getifaddrs");
        }

        for (addr = ifaddrs; addr; addr = addr->ifa_next) {
                if (addr->ifa_addr == NULL ||
                    addr->ifa_addr->sa_family != AF_LINK)
                        continue;

                sdl = (const struct sockaddr_dl *)(void *)addr->ifa_addr;
                if (sdl && sdl->sdl_index == ifindex) {
                        (void) strlcpy(ifname, addr->ifa_name, l);
                        return 0;
                }
        }

        return -1;
}

static int
getetheraddr(struct in_addr ipaddr, struct sockaddr_dl *sdl)
{
        struct ifaddrs *ifaddrs, *addr;
        in_addr_t ina, mask;
        char ifname[IFNAMSIZ];

        if (getifaddrs(&ifaddrs) != 0) {
                warn("getifaddrs");
                return -1;
        }

        for (addr = ifaddrs; addr; addr = addr->ifa_next) {
                if (addr->ifa_addr == NULL ||
                    addr->ifa_addr->sa_family != AF_INET)
                        continue;
                if ((addr->ifa_flags & (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|
                    IFF_LOOPBACK|IFF_NOARP)) != (IFF_UP|IFF_BROADCAST))
                        continue;

                mask = ((struct sockaddr_in *)(void *)addr->ifa_netmask)->sin_addr.s_addr;
                ina = ((struct sockaddr_in *)(void *)addr->ifa_addr)->sin_addr.s_addr;
                if ((ipaddr.s_addr & mask) != (ina & mask))
                        continue;
                strlcpy(ifname, addr->ifa_name, sizeof(ifname));
                break;
        }
        if (addr == NULL) {
                warnx("No interface matched %s", inet_ntoa(ipaddr));
                freeifaddrs(ifaddrs);
                return -1;
        }

        for (addr = ifaddrs; addr; addr = addr->ifa_next) {
                if (addr->ifa_addr == NULL ||
                    addr->ifa_addr->sa_family != AF_LINK)
                        continue;
                if (strcmp(ifname, addr->ifa_name) != 0)
                        continue;
                memcpy(sdl, addr->ifa_addr, sizeof(*sdl));
                freeifaddrs(ifaddrs);
                return 0;
        }
        warnx("No link address for interface %s", ifname);
        freeifaddrs(ifaddrs);
        return -1;
}

static struct in_nbrinfo *
getnbrinfo(const char *ifname, struct in_addr *addr)
{
        static struct in_nbrinfo nbi, *nbip;
        int s;

        if ((s = prog_socket(AF_INET, SOCK_DGRAM, 0)) == -1)
                err(1, "socket");

        (void)memset(&nbi, 0, sizeof(nbi));
        (void)strlcpy(nbi.ifname, ifname, sizeof(nbi.ifname));
        nbi.addr = *addr;
        if (prog_ioctl(s, SIOCGNBRINFO, &nbi) == -1) {
                warn("ioctl(SIOCGNBRINFO)");
                nbip = NULL;
        } else
                nbip = &nbi;
        (void)prog_close(s);

        return nbip;
}

static const char *
sec2str(time_t total)
{
        static char result[256];
        int days, hours, mins, secs;
        int first = 1;
        char *p = result;
        char *ep = &result[sizeof(result)];
        int n;

        days = total / 3600 / 24;
        hours = (total / 3600) % 24;
        mins = (total / 60) % 60;
        secs = total % 60;

        if (days) {
                first = 0;
                n = snprintf(p, (size_t)(ep - p), "%dd", days);
                if (n < 0 || n >= ep - p)
                        return "?";
                p += n;
        }
        if (!first || hours) {
                first = 0;
                n = snprintf(p, (size_t)(ep - p), "%dh", hours);
                if (n < 0 || n >= ep - p)
                        return "?";
                p += n;
        }
        if (!first || mins) {
                first = 0;
                n = snprintf(p, (size_t)(ep - p), "%dm", mins);
                if (n < 0 || n >= ep - p)
                        return "?";
                p += n;
        }
        (void)snprintf(p, (size_t)(ep - p), "%ds", secs);

        return(result);
}