OpenBSD WoL

Makefile

#       $OpenBSD: Makefile,v 1.3 2009/02/08 22:53:01 mbalmer dead $

PROG=           wake
SRCS=           wake.c
CFLAGS+=        -Wall -Wstrict-prototypes -Wmissing-prototypes
CFLAGS+=        -Wmissing-declarations -Wshadow -Wpointer-arith
CFLAGS+=        -Wcast-qual -Wsign-compare -Wbounded

MAN=            wake.8

.include <bsd.prog.mk>

wake.8

.\" $OpenBSD: wake.8,v 1.9 2009/02/08 22:53:01 mbalmer dead $
.\"
.\" Copyright (c) 2009 Marc Balmer <[email protected]>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: February 8 2009 $
.Dt WAKE 8
.Os
.Sh NAME
.Nm wake
.Nd "send Wake on LAN frames to hosts on a local Ethernet network"
.Sh SYNOPSIS
.Nm
.Ar interface
.Ar lladdr ...
.Sh DESCRIPTION
The
.Nm
program is used to send Wake on LAN (WoL) frames over a local
Ethernet network to one or more hosts using their link layer (hardware)
addresses.
WoL functionality is generally enabled in a machine's BIOS
and can be used to power on machines from a remote system without
having physical access to them.
.Pp
.Ar interface
is the network interface of the local machine.
.Ar lladdr
are the link layer addresses of the remote machines
and can be specified as the actual hardware address
(six hexadecimal numbers separated by colons)
or a hostname entry in
.Pa /etc/ethers .
Link layer addresses can be determined and set on
.Ox
machines using
.Xr ifconfig 8 .
.Sh FILES
.Bl -tag -width "/etc/ethers" -compact
.It /etc/ethers
Ethernet host name database.
.El
.Sh SEE ALSO
.Xr ethers 5 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
program first appeared in
.Ox 4.5 .

wake.c

/*      $OpenBSD: wake.c,v 1.15 2009/02/08 22:53:01 mbalmer dead $ */

/*
 * Copyright (C) 2006,2007,2008,2009 Marc Balmer <[email protected]>
 * 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/types.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <net/bpf.h>
#include <net/if.h>

#include <netinet/in.h>
#include <netinet/if_ether.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

#ifndef BPF_PATH_FORMAT
#define BPF_PATH_FORMAT "/dev/bpf%u"
#endif

#ifndef SYNC_LEN
#define SYNC_LEN 6
#endif

#ifndef DESTADDR_COUNT
#define DESTADDR_COUNT 16
#endif

__dead void     usage(void);

int     wake(const char *iface, const char *host);
int     get_bpf(void);
int     bind_if_to_bpf(char const *ifname, int bpf);
int     get_ether(char const *text, struct ether_addr *addr);
int     send_wakeup(int bpf, struct ether_addr const *addr);

void
usage(void)
{
        extern char *__progname;

        (void)fprintf(stderr, "usage: %s interface lladdr ...\n", __progname);
        exit(0);
}

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

        bpf = get_bpf();
        if (bpf == -1)
                return -1;
        if (bind_if_to_bpf(iface, bpf) == -1 ||
            get_ether(host, &macaddr) == -1) {
                (void)close(bpf);
                return -1;
        }
        res = send_wakeup(bpf, &macaddr);
        (void)close(bpf);
        return res;
}

int
get_bpf(void)
{
        int i, fd;
        char path[MAXPATHLEN];

        for (i = 0;; i++) {
                if (snprintf(path, sizeof(path), BPF_PATH_FORMAT, i) == -1)
                        return -1;

                fd = open(path, O_RDWR);
                if (fd != -1)
                        return fd;
                if (errno == EBUSY)
                        continue;
                break;
        }
        return -1;
}

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;
}

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))
                return -1;
        return 0;
}

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];
        } pkt;
        u_char *p;
        int i;
        ssize_t bw;
        ssize_t len;

        (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->ether_addr_octet, p, ETHER_ADDR_LEN);
        p = (u_char *)&pkt;
        len = sizeof(pkt);
        bw = 0;
        while (len) {
                if ((bw = write(bpf, &pkt, sizeof(pkt))) == -1)
                        return -1;
                len -= bw;
                p += bw;
        }
        return 0;
}

int
main(int argc, char *argv[])
{
        int n;

        if (argc < 3)
                usage();

        for (n = 2; n < argc; n++)
                if (wake(argv[1], argv[n]))
                        warn("error sending Wake on LAN frame over %s to %s",
                            argv[1], argv[n]);
        return 0;
}