net-tools/ether-wake.c

/* ether-wake.c: Send a magic packet to wake up sleeping machines. */

static char version_msg[] =
"ether-wake.c: v1.05 12/28/2000 Donald Becker, http://www.scyld.com/";
static char brief_usage_msg[] =
"usage: ether-wake [-i <ifname>] [-p aa:bb:cc:dd[:ee:ff]] 00:11:22:33:44:55\n"
"   Use '-u' to see the complete set of options.\n";
static char usage_msg[] =
"usage: ether-wake [-i <ifname>] [-p aa:bb:cc:dd[:ee:ff]] 00:11:22:33:44:55

	This program generates and transmits a Wake-On-LAN (WOL) \"Magic Packet\",
	used for restarting machines that have been soft-powered-down
	(ACPI D3-warm state).  It currently generates the standard AMD Magic Packet
	format, with an optional password appended.

	The single required parameter is the Ethernet MAC (station) address
	of the machine to wake.  This is typically retrieved with the 'arp'
	program while the target machine is awake.

	Options:
		-b	Send wake-up packet to the broadcast address.
		-D	Increase the debug level.
		-i ifname	Use interface IFNAME instead of the default 'eth0'.
		-p <pw>		Append the four or six byte password PW to the packet.
					A password is only required for a few adapter types.
					The password may be specified in ethernet hex format
					or dotted decimal (Internet address)
		-p 00:22:44:66:88:aa
		-p 192.168.1.1
";

/*
	This program generates and transmits a Wake-On-LAN (WOL) "Magic Packet",
	used for restarting machines that have been soft-powered-down
	(ACPI D3-warm state).  It currently generates the standard AMD Magic Packet
	format, with an optional password appended.

	This software may be used and distributed according to the terms
	of the GNU Public License, incorporated herein by reference.
	Contact the author for use under other terms.

	This source file is part of the network tricks package.

	The author may be reached as becker@scyld, or C/O
	 Scyld Computing Corporation
	 410 Severn Ave., Suite 210
	 Annapolis MD 21403

	The single required parameter is the Ethernet MAC (station) address
	of the machine to wake.  This is typically retrieved with the 'arp'
	program while the target machine is awake.

	Options:
		-b	Send wake-up packet to the broadcast address.
		-D	Increase the debug level.
		-i ifname	Use interface IFNAME instead of the default "eth0".
		-p <pw>		Append the four or six byte password PW to the packet.
					A password is only required for a few adapter types.
					The password may be specified in ethernet hex format
					or dotted decimal (Internet address)
		-p 00:22:44:66:88:aa
		-p 192.168.1.1

  Note: On some systems dropping root capability allows the process to be
  dumped, traced or debugged.
  If someone traces this program, they get control of a raw socket.
  Linux handles this safely, but beware when porting this program.

*/

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <string.h>

#if 0							/* Only exists on some versions. */
#include <ioctls.h>
#endif

#include <sys/socket.h>

#include <sys/types.h>
#include <sys/ioctl.h>
#include <linux/if.h>

#ifdef UIO_MAXIOV
/*extern int setsockopt __P ((int __fd, int __level, int __optname,
  __ptr_t __optval, int __optlen));*/
#else				/* New, correct head files.  */
#include <sys/socket.h>
#endif
#ifdef USE_SENDMSG
#include <iovec.h>
#endif

u_char outpack[1000];
int outpack_sz = 0;
int debug = 0;
u_char wol_passwd[6];
int wol_passwd_sz = 0;

static int opt_no_src_addr = 0, opt_broadcast = 0;

static int get_fill(unsigned char *pkt, char *arg);
static int get_wol_pw(const char *optarg);

int main(int argc, char *argv[])
{
	struct sockaddr whereto;	/* who to wake up */
	char *ifname = "eth0";
	int one = 1;				/* True, for socket options. */
	int s;						/* Raw socket */
	int errflag = 0, verbose = 0, do_version = 0;
	int i, c, pktsize;

	while ((c = getopt(argc, argv, "bDi:p:uvV")) != -1)
		switch (c) {
		case 'b': opt_broadcast++;	break;
		case 'D': debug++;			break;
		case 'i': ifname = optarg;	break;
		case 'p': get_wol_pw(optarg); break;
		case 'u': printf(usage_msg); return 0;
		case 'v': verbose++;		break;
		case 'V': do_version++;		break;
		case '?':
			errflag++;
		}
	if (verbose || do_version)
		printf("%s\n", version_msg);
	if (errflag) {
		fprintf(stderr, brief_usage_msg);
		return 3;
	}

	if (optind == argc) {
		fprintf(stderr, "Specify the Ethernet address as 00:11:22:33:44:55.\n");
		return 3;
	}

	/* Note: PF_INET, SOCK_DGRAM, IPPROTO_UDP would allow SIOCGIFHWADDR to
	   work as non-root, but we need SOCK_PACKET to specify the Ethernet
	   destination address. */
	if ((s = socket(AF_INET, SOCK_PACKET, SOCK_PACKET)) < 0) {
		if (errno == EPERM)
			fprintf(stderr, "ether-wake must run as root\n");
		else
			perror("ether-wake: socket");
		if (! debug)
			return 2;
	}
	/* Don't revert if debugging allows a normal user to get the raw socket. */
	setuid(getuid());

	pktsize = get_fill(outpack, argv[optind]);

	/* Fill in the source address, if possible.
	   The code to retrieve the local station address is Linux specific. */
	if (! opt_no_src_addr){
		struct ifreq if_hwaddr;
		unsigned char *hwaddr = if_hwaddr.ifr_hwaddr.sa_data;

		strcpy(if_hwaddr.ifr_name, ifname);
		if (ioctl(s, SIOCGIFHWADDR, &if_hwaddr) < 0) {
			fprintf(stderr, "SIOCGIFHWADDR on %s failed: %s\n", ifname,
					strerror(errno));
			return 1;
		}
		memcpy(outpack+6, if_hwaddr.ifr_hwaddr.sa_data, 6);

		if (verbose) {
			printf("The hardware address (SIOCGIFHWADDR) of %s is type %d  "
				   "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n", ifname,
				   if_hwaddr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
				   hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
		}
	}

	if (wol_passwd_sz > 0) {
		memcpy(outpack+pktsize, wol_passwd, wol_passwd_sz);
		pktsize += wol_passwd_sz;
	}

	if (verbose > 1) {
		printf("The final packet is: ");
		for (i = 0; i < pktsize; i++)
			printf(" %2.2x", outpack[i]);
		printf(".\n");
	}

	/* This is necessary for broadcasts to work */
	if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, (char *)&one, sizeof(one)) < 0)
		perror("setsockopt: SO_BROADCAST");

	whereto.sa_family = 0;
	strcpy(whereto.sa_data, ifname);

	if ((i = sendto(s, outpack, pktsize, 0, &whereto, sizeof(whereto))) < 0)
		perror("sendto");
	else if (debug)
		printf("Sendto worked ! %d.\n", i);

#ifdef USE_SEND
	if (bind(s, &whereto, sizeof(whereto)) < 0)
		perror("bind");
	else if (send(s, outpack, 100, 0) < 0)
		perror("send");
#endif
#ifdef USE_SENDMSG
	{
		struct msghdr msghdr;
		struct iovec iovector[1];
		msghdr.msg_name = &whereto;
		msghdr.msg_namelen = sizeof(whereto);
		msghdr.msg_iov = iovector;
		msghdr.msg_iovlen = 1;
		iovector[0].iov_base = outpack;
		iovector[0].iov_len = pktsize;
		if ((i = sendmsg(s, &msghdr, 0)) < 0)
			perror("sendmsg");
		else if (debug)
			printf("sendmsg worked, %d (%d).\n", i, errno);
	}
#endif

	return 0;
}

static int get_fill(unsigned char *pkt, char *arg)
{
	int sa[6];
	unsigned char station_addr[6];
	int byte_cnt;
	int offset, i;
	char *cp;

	for (cp = arg; *cp; cp++)
		if (*cp != ':' && !isxdigit(*cp)) {
			(void)fprintf(stderr,
						  "ping: patterns must be specified as hex digits.\n");
			exit(2);
		}

	byte_cnt = sscanf(arg, "%2x:%2x:%2x:%2x:%2x:%2x",
					  &sa[0], &sa[1], &sa[2], &sa[3], &sa[4], &sa[5]);
	for (i = 0; i < 6; i++)
		station_addr[i] = sa[i];
	if (debug)
		fprintf(stderr, "Command line stations address is "
				"%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n",
				sa[0], sa[1], sa[2], sa[3], sa[4], sa[5]);

	if (byte_cnt != 6) {
		(void)fprintf(stderr,
					  "ping: The Magic Packet address must be specified as "
					  "00:11:22:33:44:55.\n");
		exit(2);
	}

	if (opt_broadcast)
		memset(pkt+0, 0xff, 6);
	else
		memcpy(pkt, station_addr, 6);
	memcpy(pkt+6, station_addr, 6);
	pkt[12] = 0x08;				/* Or 0x0806 for ARP, 0x8035 for RARP */
	pkt[13] = 0x42;
	offset = 14;

	memset(pkt+offset, 0xff, 6);
	offset += 6;

	for (i = 0; i < 16; i++) {
		memcpy(pkt+offset, station_addr, 6);
		offset += 6;
	}
	if (debug) {
		fprintf(stderr, "Packet is ");
		for (i = 0; i < offset; i++)
			fprintf(stderr, " %2.2x", pkt[i]);
		fprintf(stderr, ".\n");
	}
	return offset;
}

static int get_wol_pw(const char *optarg)
{
	int passwd[6];
	int byte_cnt;
	int i;

	byte_cnt = sscanf(optarg, "%2x:%2x:%2x:%2x:%2x:%2x",
					  &passwd[0], &passwd[1], &passwd[2],
					  &passwd[3], &passwd[4], &passwd[5]);
	if (byte_cnt < 4)
		byte_cnt = sscanf(optarg, "%d.%d.%d.%d",
						  &passwd[0], &passwd[1], &passwd[2], &passwd[3]);
	if (byte_cnt < 4) {
		fprintf(stderr, "Unable to read the Wake-On-LAN password.\n");
		return 0;
	}
	printf(" The Magic packet password is %2.2x %2.2x %2.2x %2.2x (%d).\n",
		   passwd[0], passwd[1], passwd[2], passwd[3], byte_cnt);
	for (i = 0; i < byte_cnt; i++)
		wol_passwd[i] = passwd[i];
	return wol_passwd_sz = byte_cnt;
}

#if 0
{
	to = (struct sockaddr_in *)&whereto;
	to->sin_family = AF_INET;
	if (inet_aton(target, &to->sin_addr)) {
		hostname = target;
	}
	memset (&sa, 0, sizeof sa);
	sa.sa_family = AF_INET;
	strncpy (sa.sa_data, interface, sizeof sa.sa_data);
	sendto (sock, buf, bufix + len, 0, &sa, sizeof sa);
	strncpy (sa.sa_data, interface, sizeof sa.sa_data);
#if 1
	sendto (sock, buf, bufix + len, 0, &sa, sizeof sa);
#else
	bind (sock, &sa, sizeof sa);
	connect();
	send (sock, buf, bufix + len, 0);
#endif
}
#endif


/*
 * Local variables:
 *  compile-command: "gcc -O -Wall -o ether-wake ether-wake.c"
 *  c-indent-level: 4
 *  c-basic-offset: 4
 *  c-indent-level: 4
 *  tab-width: 4
 * End:
 */