/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2006, 2007, 2008, 2009, 2010 Marc Balmer <marc@msys.ch>
 * Copyright (C) 2000 Eugene M. Kim.  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. Author's name may not be used endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <net/bpf.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>

#include <err.h>
#include <fcntl.h>
#include <ifaddrs.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define _PATH_BPF       "/dev/bpf"

#ifndef SYNC_LEN
#define SYNC_LEN        6
#endif

#ifndef DESTADDR_COUNT
#define DESTADDR_COUNT  16
#endif

static int      bind_if_to_bpf(char const *ifname, int bpf);
static int      find_ether(char *dst, size_t len);
static int      get_ether(char const *text, struct ether_addr *addr);
static int      send_wakeup(int bpf, struct ether_addr const *addr);
static void     usage(void);
static int      wake(int bpf, const char *host);

static void
usage(void)
{

        (void)fprintf(stderr, "usage: wake [interface] lladdr [lladdr ...]\n");
        exit(1);
}

static int
wake(int bpf, const char *host)
{
        struct ether_addr macaddr;

        if (get_ether(host, &macaddr) == -1)
                return (-1);

        return (send_wakeup(bpf, &macaddr));
}

static int
bind_if_to_bpf(char const *ifname, int bpf)
{
        struct ifreq ifr;
        u_int dlt;

        if (strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)) >=
            sizeof(ifr.ifr_name))
                return (-1);

        if (ioctl(bpf, BIOCSETIF, &ifr) == -1)
                return (-1);

        if (ioctl(bpf, BIOCGDLT, &dlt) == -1)
                return (-1);

        if (dlt != DLT_EN10MB)
                return (-1);

        return (0);
}

static int
find_ether(char *dst, size_t len)
{
        struct ifaddrs *ifap, *ifa;
        struct sockaddr_dl *sdl = NULL;
        int nifs;

        if (dst == NULL || len == 0)
                return (0);

        if (getifaddrs(&ifap) != 0)
                return (-1);

        /* XXX also check the link state */
        for (nifs = 0, ifa = ifap; ifa; ifa = ifa->ifa_next)
                if (ifa->ifa_addr->sa_family == AF_LINK &&
                    ifa->ifa_flags & IFF_UP && ifa->ifa_flags & IFF_RUNNING) {
                        sdl = (struct sockaddr_dl *)ifa->ifa_addr;
                        if (sdl->sdl_type == IFT_ETHER) {
                                strlcpy(dst, ifa->ifa_name, len);
                                nifs++;
                        }
                }

        freeifaddrs(ifap);
        return (nifs == 1 ? 0 : -1);
}

static int
get_ether(char const *text, struct ether_addr *addr)
{
        struct ether_addr *paddr;

        paddr = ether_aton(text);
        if (paddr != NULL) {
                *addr = *paddr;
                return (0);
        }
        if (ether_hostton(text, addr)) {
                warnx("no match for host %s found", text);
                return (-1);
        }
        return (0);
}

static int
send_wakeup(int bpf, struct ether_addr const *addr)
{
        struct {
                struct ether_header hdr;
                u_char data[SYNC_LEN + ETHER_ADDR_LEN * DESTADDR_COUNT];
        } __packed pkt;
        u_char *p;
        ssize_t bw;
        ssize_t len;
        int i;

        (void)memset(pkt.hdr.ether_dhost, 0xff, sizeof(pkt.hdr.ether_dhost));
        pkt.hdr.ether_type = htons(0);
        (void)memset(pkt.data, 0xff, SYNC_LEN);
        for (p = pkt.data + SYNC_LEN, i = 0; i < DESTADDR_COUNT;
            p += ETHER_ADDR_LEN, i++)
                bcopy(addr->octet, p, ETHER_ADDR_LEN);
        p = (u_char *)&pkt;
        len = sizeof(pkt);
        bw = 0;
        while (len) {
                if ((bw = write(bpf, p, len)) == -1) {
                        warn("write()");
                        return (-1);
                }
                len -= bw;
                p += bw;
        }
        return (0);
}

int
main(int argc, char *argv[])
{
        int bpf, n, rval;
        char ifname[IF_NAMESIZE];

        if (argc < 2)
                usage();

        if ((bpf = open(_PATH_BPF, O_RDWR)) == -1)
                err(1, "Cannot open bpf interface");

        n = 2;
        if (bind_if_to_bpf(argv[1], bpf) == -1) {
                if (find_ether(ifname, sizeof(ifname)))
                        err(1, "Failed to determine ethernet interface");
                if (bind_if_to_bpf(ifname, bpf) == -1)
                        err(1, "Cannot bind to interface `%s'", ifname);
                --n;
        } else
                strlcpy(ifname, argv[1], sizeof(ifname));

        if (n >= argc)
                usage();
        rval = 0;
        for (; n < argc; n++) {
                if (wake(bpf, argv[n]) != 0) {
                        rval = 1;
                        warn("Cannot send Wake on LAN frame over `%s' to `%s'",
                            ifname, argv[n]);
                }
        }
        exit(rval);
}