aboutsummaryrefslogtreecommitdiff
path: root/networking/ether-wake.c
blob: fc26ad07d127e5214dfdf8237077f72e48c93b31 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
/* vi: set sw=4 ts=4: */
/*
 * ether-wake.c - Send a magic packet to wake up sleeping machines.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 * Author:      Donald Becker, http://www.scyld.com/"; http://www.scyld.com/wakeonlan.html
 * Busybox port: Christian Volkmann <haveaniceday@online.de>
 *               Used version of ether-wake.c: v1.09 11/12/2003 Donald Becker, http://www.scyld.com/";
 */

/* full usage according Donald Becker
 * usage: ether-wake [-i <ifname>] [-p aa:bb:cc:dd[:ee:ff]] 00:11:22:33:44:55\n"
 *
 *	This program generates and transmits a Wake-On-LAN (WOL)\n"
 *	\"Magic Packet\", used for restarting machines that have been\n"
 *	soft-powered-down (ACPI D3-warm state).\n"
 *	It currently generates the standard AMD Magic Packet format, with\n"
 *	an optional password appended.\n"
 *
 *	The single required parameter is the Ethernet MAC (station) address\n"
 *	of the machine to wake or a host ID with known NSS 'ethers' entry.\n"
 *	The MAC address may be found with the 'arp' program while the target\n"
 *	machine is awake.\n"
 *
 *	Options:\n"
 *		-b	Send wake-up packet to the broadcast address.\n"
 *		-D	Increase the debug level.\n"
 *		-i ifname	Use interface IFNAME instead of the default 'eth0'.\n"
 *		-p <pw>		Append the four or six byte password PW to the packet.\n"
 *					A password is only required for a few adapter types.\n"
 *					The password may be specified in ethernet hex format\n"
 *					or dotted decimal (Internet address)\n"
 *		-p 00:22:44:66:88:aa\n"
 *		-p 192.168.1.1\n";
 *
 *
 *	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 was originally part of the network tricks package, and
 *	is now distributed to support the Scyld Beowulf system.
 *	Copyright 1999-2003 Donald Becker and Scyld Computing Corporation.
 *
 *	The author may be reached as becker@scyld, or C/O
 *	 Scyld Computing Corporation
 *	 914 Bay Ridge Road, Suite 220
 *	 Annapolis MD 21403
 *
 *   Notes:
 *   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.
 *
 *   An alternative to needing 'root' is using a UDP broadcast socket, however
 *   doing so only works with adapters configured for unicast+broadcast Rx
 *   filter.  That configuration consumes more power.
*/


#include <netpacket/packet.h>
#include <net/ethernet.h>
#include <netinet/ether.h>
#include <linux/if.h>

#include "libbb.h"

/* 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.
 */
#ifdef PF_PACKET
# define whereto_t sockaddr_ll
# define make_socket() xsocket(PF_PACKET, SOCK_RAW, 0)
#else
# define whereto_t sockaddr
# define make_socket() xsocket(AF_INET, SOCK_PACKET, SOCK_PACKET)
#endif

#ifdef DEBUG
# define bb_debug_msg(fmt, args...) fprintf(stderr, fmt, ## args)
void bb_debug_dump_packet(unsigned char *outpack, int pktsize)
{
	int i;
	printf("packet dump:\n");
	for (i = 0; i < pktsize; ++i) {
		printf("%2.2x ", outpack[i]);
		if (i % 20 == 19) bb_putchar('\n');
	}
	printf("\n\n");
}
#else
# define bb_debug_msg(fmt, args...)             ((void)0)
# define bb_debug_dump_packet(outpack, pktsize) ((void)0)
#endif

/* Convert the host ID string to a MAC address.
 * The string may be a:
 *    Host name
 *    IP address string
 *    MAC address string
*/
static void get_dest_addr(const char *hostid, struct ether_addr *eaddr)
{
	struct ether_addr *eap;

	eap = ether_aton(hostid);
	if (eap) {
		*eaddr = *eap;
		bb_debug_msg("The target station address is %s\n\n", ether_ntoa(eaddr));
#if !defined(__UCLIBC__)
	} else if (ether_hostton(hostid, eaddr) == 0) {
		bb_debug_msg("Station address for hostname %s is %s\n\n", hostid, ether_ntoa(eaddr));
#endif
	} else
		bb_show_usage();
}

static int get_fill(unsigned char *pkt, struct ether_addr *eaddr, int broadcast)
{
	int i;
	unsigned char *station_addr = eaddr->ether_addr_octet;

	memset(pkt, 0xff, 6);
	if (!broadcast)
		memcpy(pkt, station_addr, 6);
	pkt += 6;

	memcpy(pkt, station_addr, 6); /* 6 */
	pkt += 6;

	*pkt++ = 0x08; /* 12 */ /* Or 0x0806 for ARP, 0x8035 for RARP */
	*pkt++ = 0x42; /* 13 */

	memset(pkt, 0xff, 6); /* 14 */

	for (i = 0; i < 16; ++i) {
		pkt += 6;
		memcpy(pkt, station_addr, 6); /* 20,26,32,... */
	}

	return 20 + 16*6; /* length of packet */
}

static int get_wol_pw(const char *ethoptarg, unsigned char *wol_passwd)
{
	unsigned passwd[6];
	int byte_cnt, i;

	/* handle MAC format */
	byte_cnt = sscanf(ethoptarg, "%2x:%2x:%2x:%2x:%2x:%2x",
	                  &passwd[0], &passwd[1], &passwd[2],
	                  &passwd[3], &passwd[4], &passwd[5]);
	/* handle IP format */
// FIXME: why < 4?? should it be < 6?
	if (byte_cnt < 4)
		byte_cnt = sscanf(ethoptarg, "%u.%u.%u.%u",
		                  &passwd[0], &passwd[1], &passwd[2], &passwd[3]);
	if (byte_cnt < 4) {
		bb_error_msg("cannot read Wake-On-LAN pass");
		return 0;
	}
// TODO: check invalid numbers >255??
	for (i = 0; i < byte_cnt; ++i)
		wol_passwd[i] = passwd[i];

	bb_debug_msg("password: %2.2x %2.2x %2.2x %2.2x (%d)\n\n",
	             wol_passwd[0], wol_passwd[1], wol_passwd[2], wol_passwd[3],
	             byte_cnt);

	return byte_cnt;
}

int ether_wake_main(int argc, char **argv);
int ether_wake_main(int argc, char **argv)
{
	const char *ifname = "eth0";
	char *pass;
	unsigned flags;
	unsigned char wol_passwd[6];
	int wol_passwd_sz = 0;
	int s;						/* Raw socket */
	int pktsize;
	unsigned char outpack[1000];

	struct ether_addr eaddr;
	struct whereto_t whereto;	/* who to wake up */

	/* handle misc user options */
	opt_complementary = "=1";
	flags = getopt32(argv, "bi:p:", &ifname, &pass);
	if (flags & 4) /* -p */
		wol_passwd_sz = get_wol_pw(pass, wol_passwd);
	flags &= 1; /* we further interested only in -b [bcast] flag */

	/* create the raw socket */
	s = make_socket();

	/* now that we have a raw socket we can drop root */
	/* xsetuid(getuid()); - but save on code size... */

	/* look up the dest mac address */
	get_dest_addr(argv[optind], &eaddr);

	/* fill out the header of the packet */
	pktsize = get_fill(outpack, &eaddr, flags /* & 1 OPT_BROADCAST */);

	bb_debug_dump_packet(outpack, pktsize);

	/* Fill in the source address, if possible. */
#ifdef __linux__
	{
		struct ifreq if_hwaddr;

		strncpy(if_hwaddr.ifr_name, ifname, sizeof(if_hwaddr.ifr_name));
		ioctl_or_perror_and_die(s, SIOCGIFHWADDR, &if_hwaddr, "SIOCGIFHWADDR on %s failed", ifname);

		memcpy(outpack+6, if_hwaddr.ifr_hwaddr.sa_data, 6);

# ifdef DEBUG
		{
			unsigned char *hwaddr = if_hwaddr.ifr_hwaddr.sa_data;
			printf("The hardware address (SIOCGIFHWADDR) of %s is type %d  "
				   "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x\n\n", ifname,
				   if_hwaddr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
				   hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
		}
# endif
	}
#endif /* __linux__ */

	bb_debug_dump_packet(outpack, pktsize);

	/* append the password if specified */
	if (wol_passwd_sz > 0) {
		memcpy(outpack+pktsize, wol_passwd, wol_passwd_sz);
		pktsize += wol_passwd_sz;
	}

	bb_debug_dump_packet(outpack, pktsize);

	/* This is necessary for broadcasts to work */
	if (flags /* & 1 OPT_BROADCAST */) {
		if (setsockopt_broadcast(s) != 0)
			bb_perror_msg("SO_BROADCAST");
	}

#if defined(PF_PACKET)
	{
		struct ifreq ifr;
		strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
		xioctl(s, SIOCGIFINDEX, &ifr);
		memset(&whereto, 0, sizeof(whereto));
		whereto.sll_family = AF_PACKET;
		whereto.sll_ifindex = ifr.ifr_ifindex;
		/* The manual page incorrectly claims the address must be filled.
		   We do so because the code may change to match the docs. */
		whereto.sll_halen = ETH_ALEN;
		memcpy(whereto.sll_addr, outpack, ETH_ALEN);
	}
#else
	whereto.sa_family = 0;
	strcpy(whereto.sa_data, ifname);
#endif
	xsendto(s, outpack, pktsize, (struct sockaddr *)&whereto, sizeof(whereto));
	if (ENABLE_FEATURE_CLEAN_UP)
		close(s);
	return EXIT_SUCCESS;
}