1 /* vi: set sw=4 ts=4: */
2 /*
3 * ether-wake.c - Send a magic packet to wake up sleeping machines.
4 *
5 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
6 *
7 * Author: Donald Becker, http://www.scyld.com/"; http://www.scyld.com/wakeonlan.html
8 * Busybox port: Christian Volkmann <haveaniceday@online.de>
9 * Used version of ether-wake.c: v1.09 11/12/2003 Donald Becker, http://www.scyld.com/";
10 */
11
12 /* full usage according Donald Becker
13 * usage: ether-wake [-i <ifname>] [-p aa:bb:cc:dd[:ee:ff]] 00:11:22:33:44:55\n"
14 *
15 * This program generates and transmits a Wake-On-LAN (WOL)\n"
16 * \"Magic Packet\", used for restarting machines that have been\n"
17 * soft-powered-down (ACPI D3-warm state).\n"
18 * It currently generates the standard AMD Magic Packet format, with\n"
19 * an optional password appended.\n"
20 *
21 * The single required parameter is the Ethernet MAC (station) address\n"
22 * of the machine to wake or a host ID with known NSS 'ethers' entry.\n"
23 * The MAC address may be found with the 'arp' program while the target\n"
24 * machine is awake.\n"
25 *
26 * Options:\n"
27 * -b Send wake-up packet to the broadcast address.\n"
28 * -D Increase the debug level.\n"
29 * -i ifname Use interface IFNAME instead of the default 'eth0'.\n"
30 * -p <pw> Append the four or six byte password PW to the packet.\n"
31 * A password is only required for a few adapter types.\n"
32 * The password may be specified in ethernet hex format\n"
33 * or dotted decimal (Internet address)\n"
34 * -p 00:22:44:66:88:aa\n"
35 * -p 192.168.1.1\n";
36 *
37 *
38 * This program generates and transmits a Wake-On-LAN (WOL) "Magic Packet",
39 * used for restarting machines that have been soft-powered-down
40 * (ACPI D3-warm state). It currently generates the standard AMD Magic Packet
41 * format, with an optional password appended.
42 *
43 * This software may be used and distributed according to the terms
44 * of the GNU Public License, incorporated herein by reference.
45 * Contact the author for use under other terms.
46 *
47 * This source file was originally part of the network tricks package, and
48 * is now distributed to support the Scyld Beowulf system.
49 * Copyright 1999-2003 Donald Becker and Scyld Computing Corporation.
50 *
51 * The author may be reached as becker@scyld, or C/O
52 * Scyld Computing Corporation
53 * 914 Bay Ridge Road, Suite 220
54 * Annapolis MD 21403
55 *
56 * Notes:
57 * On some systems dropping root capability allows the process to be
58 * dumped, traced or debugged.
59 * If someone traces this program, they get control of a raw socket.
60 * Linux handles this safely, but beware when porting this program.
61 *
62 * An alternative to needing 'root' is using a UDP broadcast socket, however
63 * doing so only works with adapters configured for unicast+broadcast Rx
64 * filter. That configuration consumes more power.
65 */
66 //config:config ETHER_WAKE
67 //config: bool "ether-wake (4.9 kb)"
68 //config: default y
69 //config: help
70 //config: Send a magic packet to wake up sleeping machines.
71
72 //applet:IF_ETHER_WAKE(APPLET_ODDNAME(ether-wake, ether_wake, BB_DIR_USR_SBIN, BB_SUID_DROP, ether_wake))
73
74 //kbuild:lib-$(CONFIG_ETHER_WAKE) += ether-wake.o
75
76 //usage:#define ether_wake_trivial_usage
77 //usage: "[-b] [-i IFACE] [-p aa:bb:cc:dd[:ee:ff]/a.b.c.d] MAC"
78 //usage:#define ether_wake_full_usage "\n\n"
79 //usage: "Send a magic packet to wake up sleeping machines.\n"
80 //usage: "MAC must be a station address (00:11:22:33:44:55) or\n"
81 //usage: "a hostname with a known 'ethers' entry.\n"
82 //usage: "\n -b Broadcast the packet"
83 //usage: "\n -i IFACE Interface to use (default eth0)"
84 //usage: "\n -p PASSWORD Append four or six byte PASSWORD to the packet"
85
86 #include "libbb.h"
87 #include <netpacket/packet.h>
88 #include <netinet/ether.h>
89 #include <linux/if.h>
90
91 /* Note: PF_INET, SOCK_DGRAM, IPPROTO_UDP would allow SIOCGIFHWADDR to
92 * work as non-root, but we need SOCK_PACKET to specify the Ethernet
93 * destination address.
94 */
95 #ifdef PF_PACKET
96 # define whereto_t sockaddr_ll
97 # define make_socket() xsocket(PF_PACKET, SOCK_RAW, 0)
98 #else
99 # define whereto_t sockaddr
100 # define make_socket() xsocket(AF_INET, SOCK_PACKET, SOCK_PACKET)
101 #endif
102
103 #ifdef DEBUG
104 # define bb_debug_msg(fmt, args...) fprintf(stderr, fmt, ## args)
bb_debug_dump_packet(unsigned char * outpack,int pktsize)105 void bb_debug_dump_packet(unsigned char *outpack, int pktsize)
106 {
107 int i;
108 printf("packet dump:\n");
109 for (i = 0; i < pktsize; ++i) {
110 printf("%2.2x ", outpack[i]);
111 if (i % 20 == 19) bb_putchar('\n');
112 }
113 printf("\n\n");
114 }
115 #else
116 # define bb_debug_msg(fmt, args...) ((void)0)
117 # define bb_debug_dump_packet(outpack, pktsize) ((void)0)
118 #endif
119
120 /* Convert the host ID string to a MAC address.
121 * The string may be a:
122 * Host name
123 * IP address string
124 * MAC address string
125 */
get_dest_addr(const char * hostid,struct ether_addr * eaddr)126 static void get_dest_addr(const char *hostid, struct ether_addr *eaddr)
127 {
128 struct ether_addr *eap;
129
130 eap = ether_aton_r(hostid, eaddr);
131 if (eap) {
132 bb_debug_msg("The target station address is %s\n\n", ether_ntoa(eap));
133 #if !defined(__UCLIBC__) || UCLIBC_VERSION >= KERNEL_VERSION(0, 9, 30)
134 } else if (ether_hostton(hostid, eaddr) == 0) {
135 bb_debug_msg("Station address for hostname %s is %s\n\n", hostid, ether_ntoa(eaddr));
136 #endif
137 } else {
138 bb_show_usage();
139 }
140 }
141
142 #define PKT_HEADER_SIZE (20 + 16*6)
fill_pkt_header(unsigned char * pkt,struct ether_addr * eaddr,int broadcast)143 static int fill_pkt_header(unsigned char *pkt, struct ether_addr *eaddr, int broadcast)
144 {
145 int i;
146 unsigned char *station_addr = eaddr->ether_addr_octet;
147
148 memset(pkt, 0xff, 6);
149 if (!broadcast)
150 memcpy(pkt, station_addr, 6);
151 pkt += 6;
152
153 memcpy(pkt, station_addr, 6); /* 6 */
154 pkt += 6;
155
156 *pkt++ = 0x08; /* 12 */ /* Or 0x0806 for ARP, 0x8035 for RARP */
157 *pkt++ = 0x42; /* 13 */
158
159 memset(pkt, 0xff, 6); /* 14 */
160
161 for (i = 0; i < 16; ++i) {
162 pkt += 6;
163 memcpy(pkt, station_addr, 6); /* 20,26,32,... */
164 }
165
166 return PKT_HEADER_SIZE; /* length of packet */
167 }
168
get_wol_pw(const char * ethoptarg,unsigned char * wol_passwd)169 static int get_wol_pw(const char *ethoptarg, unsigned char *wol_passwd)
170 {
171 unsigned passwd[6];
172 int byte_cnt, i;
173
174 /* handle MAC format */
175 byte_cnt = sscanf(ethoptarg, "%2x:%2x:%2x:%2x:%2x:%2x",
176 &passwd[0], &passwd[1], &passwd[2],
177 &passwd[3], &passwd[4], &passwd[5]);
178 /* handle IP format */
179 // FIXME: why < 4?? should it be < 6?
180 if (byte_cnt < 4)
181 byte_cnt = sscanf(ethoptarg, "%u.%u.%u.%u",
182 &passwd[0], &passwd[1], &passwd[2], &passwd[3]);
183 if (byte_cnt < 4) {
184 bb_simple_error_msg("can't read Wake-On-LAN pass");
185 return 0;
186 }
187 // TODO: check invalid numbers >255??
188 for (i = 0; i < byte_cnt; ++i)
189 wol_passwd[i] = passwd[i];
190
191 bb_debug_msg("password: %2.2x %2.2x %2.2x %2.2x (%d)\n\n",
192 wol_passwd[0], wol_passwd[1], wol_passwd[2], wol_passwd[3],
193 byte_cnt);
194
195 return byte_cnt;
196 }
197
198 int ether_wake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
ether_wake_main(int argc UNUSED_PARAM,char ** argv)199 int ether_wake_main(int argc UNUSED_PARAM, char **argv)
200 {
201 const char *ifname = "eth0";
202 char *pass;
203 unsigned flags;
204 unsigned char wol_passwd[6];
205 int wol_passwd_sz = 0;
206 int s; /* Raw socket */
207 int pktsize;
208 unsigned char outpack[PKT_HEADER_SIZE + 6 /* max passwd size */ + 16 /* paranoia */];
209
210 struct ether_addr eaddr;
211 struct whereto_t whereto; /* who to wake up */
212
213 /* handle misc user options */
214 flags = getopt32(argv, "^" "bi:p:" "\0" "=1", &ifname, &pass);
215 if (flags & 4) /* -p */
216 wol_passwd_sz = get_wol_pw(pass, wol_passwd);
217 flags &= 1; /* we further interested only in -b [bcast] flag */
218
219 /* create the raw socket */
220 s = make_socket();
221
222 /* now that we have a raw socket we can drop root */
223 /* xsetuid(getuid()); - but save on code size... */
224
225 /* look up the dest mac address */
226 get_dest_addr(argv[optind], &eaddr);
227
228 /* fill out the header of the packet */
229 pktsize = fill_pkt_header(outpack, &eaddr, flags /* & 1 OPT_BROADCAST */);
230
231 bb_debug_dump_packet(outpack, pktsize);
232
233 /* Fill in the source address, if possible. */
234 #ifdef __linux__
235 {
236 struct ifreq if_hwaddr;
237
238 strncpy_IFNAMSIZ(if_hwaddr.ifr_name, ifname);
239 ioctl_or_perror_and_die(s, SIOCGIFHWADDR, &if_hwaddr, "SIOCGIFHWADDR on %s failed", ifname);
240
241 memcpy(outpack+6, if_hwaddr.ifr_hwaddr.sa_data, 6);
242
243 # ifdef DEBUG
244 {
245 unsigned char *hwaddr = if_hwaddr.ifr_hwaddr.sa_data;
246 printf("The hardware address (SIOCGIFHWADDR) of %s is type %d "
247 "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x\n\n", ifname,
248 if_hwaddr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
249 hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
250 }
251 # endif
252 }
253 #endif /* __linux__ */
254
255 bb_debug_dump_packet(outpack, pktsize);
256
257 /* append the password if specified */
258 if (wol_passwd_sz > 0) {
259 memcpy(outpack+pktsize, wol_passwd, wol_passwd_sz);
260 pktsize += wol_passwd_sz;
261 }
262
263 bb_debug_dump_packet(outpack, pktsize);
264
265 /* This is necessary for broadcasts to work */
266 if (flags /* & 1 OPT_BROADCAST */) {
267 if (setsockopt_broadcast(s) != 0)
268 bb_simple_perror_msg("SO_BROADCAST");
269 }
270
271 #if defined(PF_PACKET)
272 {
273 struct ifreq ifr;
274 strncpy_IFNAMSIZ(ifr.ifr_name, ifname);
275 xioctl(s, SIOCGIFINDEX, &ifr);
276 memset(&whereto, 0, sizeof(whereto));
277 whereto.sll_family = AF_PACKET;
278 whereto.sll_ifindex = ifr.ifr_ifindex;
279 /* The manual page incorrectly claims the address must be filled.
280 We do so because the code may change to match the docs. */
281 whereto.sll_halen = ETH_ALEN;
282 memcpy(whereto.sll_addr, outpack, ETH_ALEN);
283 }
284 #else
285 whereto.sa_family = 0;
286 strcpy(whereto.sa_data, ifname);
287 #endif
288 xsendto(s, outpack, pktsize, (struct sockaddr *)&whereto, sizeof(whereto));
289 if (ENABLE_FEATURE_CLEAN_UP)
290 close(s);
291 return EXIT_SUCCESS;
292 }
293