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"
68 //config: default y
69 //config: select PLATFORM_LINUX
70 //config: help
71 //config: Send a magic packet to wake up sleeping machines.
72
73 //applet:IF_ETHER_WAKE(APPLET_ODDNAME(ether-wake, ether_wake, BB_DIR_USR_SBIN, BB_SUID_DROP, ether_wake))
74
75 //kbuild:lib-$(CONFIG_ETHER_WAKE) += ether-wake.o
76
77 //usage:#define ether_wake_trivial_usage
78 //usage: "[-b] [-i IFACE] [-p aa:bb:cc:dd[:ee:ff]/a.b.c.d] MAC"
79 //usage:#define ether_wake_full_usage "\n\n"
80 //usage: "Send a magic packet to wake up sleeping machines.\n"
81 //usage: "MAC must be a station address (00:11:22:33:44:55) or\n"
82 //usage: "a hostname with a known 'ethers' entry.\n"
83 //usage: "\n -b Broadcast the packet"
84 //usage: "\n -i IFACE Interface to use (default eth0)"
85 //usage: "\n -p PASSWORD Append four or six byte PASSWORD to the packet"
86
87 #include "libbb.h"
88 #include <netpacket/packet.h>
89 #include <netinet/ether.h>
90 #include <linux/if.h>
91
92 /* Note: PF_INET, SOCK_DGRAM, IPPROTO_UDP would allow SIOCGIFHWADDR to
93 * work as non-root, but we need SOCK_PACKET to specify the Ethernet
94 * destination address.
95 */
96 #ifdef PF_PACKET
97 # define whereto_t sockaddr_ll
98 # define make_socket() xsocket(PF_PACKET, SOCK_RAW, 0)
99 #else
100 # define whereto_t sockaddr
101 # define make_socket() xsocket(AF_INET, SOCK_PACKET, SOCK_PACKET)
102 #endif
103
104 #ifdef DEBUG
105 # define bb_debug_msg(fmt, args...) fprintf(stderr, fmt, ## args)
bb_debug_dump_packet(unsigned char * outpack,int pktsize)106 void bb_debug_dump_packet(unsigned char *outpack, int pktsize)
107 {
108 int i;
109 printf("packet dump:\n");
110 for (i = 0; i < pktsize; ++i) {
111 printf("%2.2x ", outpack[i]);
112 if (i % 20 == 19) bb_putchar('\n');
113 }
114 printf("\n\n");
115 }
116 #else
117 # define bb_debug_msg(fmt, args...) ((void)0)
118 # define bb_debug_dump_packet(outpack, pktsize) ((void)0)
119 #endif
120
121 /* Convert the host ID string to a MAC address.
122 * The string may be a:
123 * Host name
124 * IP address string
125 * MAC address string
126 */
get_dest_addr(const char * hostid,struct ether_addr * eaddr)127 static void get_dest_addr(const char *hostid, struct ether_addr *eaddr)
128 {
129 struct ether_addr *eap;
130
131 eap = ether_aton_r(hostid, eaddr);
132 if (eap) {
133 bb_debug_msg("The target station address is %s\n\n", ether_ntoa(eap));
134 #if !defined(__UCLIBC__) || UCLIBC_VERSION >= KERNEL_VERSION(0, 9, 30)
135 } else if (ether_hostton(hostid, eaddr) == 0) {
136 bb_debug_msg("Station address for hostname %s is %s\n\n", hostid, ether_ntoa(eaddr));
137 #endif
138 } else {
139 bb_show_usage();
140 }
141 }
142
143 #define PKT_HEADER_SIZE (20 + 16*6)
fill_pkt_header(unsigned char * pkt,struct ether_addr * eaddr,int broadcast)144 static int fill_pkt_header(unsigned char *pkt, struct ether_addr *eaddr, int broadcast)
145 {
146 int i;
147 unsigned char *station_addr = eaddr->ether_addr_octet;
148
149 memset(pkt, 0xff, 6);
150 if (!broadcast)
151 memcpy(pkt, station_addr, 6);
152 pkt += 6;
153
154 memcpy(pkt, station_addr, 6); /* 6 */
155 pkt += 6;
156
157 *pkt++ = 0x08; /* 12 */ /* Or 0x0806 for ARP, 0x8035 for RARP */
158 *pkt++ = 0x42; /* 13 */
159
160 memset(pkt, 0xff, 6); /* 14 */
161
162 for (i = 0; i < 16; ++i) {
163 pkt += 6;
164 memcpy(pkt, station_addr, 6); /* 20,26,32,... */
165 }
166
167 return PKT_HEADER_SIZE; /* length of packet */
168 }
169
get_wol_pw(const char * ethoptarg,unsigned char * wol_passwd)170 static int get_wol_pw(const char *ethoptarg, unsigned char *wol_passwd)
171 {
172 unsigned passwd[6];
173 int byte_cnt, i;
174
175 /* handle MAC format */
176 byte_cnt = sscanf(ethoptarg, "%2x:%2x:%2x:%2x:%2x:%2x",
177 &passwd[0], &passwd[1], &passwd[2],
178 &passwd[3], &passwd[4], &passwd[5]);
179 /* handle IP format */
180 // FIXME: why < 4?? should it be < 6?
181 if (byte_cnt < 4)
182 byte_cnt = sscanf(ethoptarg, "%u.%u.%u.%u",
183 &passwd[0], &passwd[1], &passwd[2], &passwd[3]);
184 if (byte_cnt < 4) {
185 bb_error_msg("can't read Wake-On-LAN pass");
186 return 0;
187 }
188 // TODO: check invalid numbers >255??
189 for (i = 0; i < byte_cnt; ++i)
190 wol_passwd[i] = passwd[i];
191
192 bb_debug_msg("password: %2.2x %2.2x %2.2x %2.2x (%d)\n\n",
193 wol_passwd[0], wol_passwd[1], wol_passwd[2], wol_passwd[3],
194 byte_cnt);
195
196 return byte_cnt;
197 }
198
199 int ether_wake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
ether_wake_main(int argc UNUSED_PARAM,char ** argv)200 int ether_wake_main(int argc UNUSED_PARAM, char **argv)
201 {
202 const char *ifname = "eth0";
203 char *pass;
204 unsigned flags;
205 unsigned char wol_passwd[6];
206 int wol_passwd_sz = 0;
207 int s; /* Raw socket */
208 int pktsize;
209 unsigned char outpack[PKT_HEADER_SIZE + 6 /* max passwd size */ + 16 /* paranoia */];
210
211 struct ether_addr eaddr;
212 struct whereto_t whereto; /* who to wake up */
213
214 /* handle misc user options */
215 opt_complementary = "=1";
216 flags = getopt32(argv, "bi:p:", &ifname, &pass);
217 if (flags & 4) /* -p */
218 wol_passwd_sz = get_wol_pw(pass, wol_passwd);
219 flags &= 1; /* we further interested only in -b [bcast] flag */
220
221 /* create the raw socket */
222 s = make_socket();
223
224 /* now that we have a raw socket we can drop root */
225 /* xsetuid(getuid()); - but save on code size... */
226
227 /* look up the dest mac address */
228 get_dest_addr(argv[optind], &eaddr);
229
230 /* fill out the header of the packet */
231 pktsize = fill_pkt_header(outpack, &eaddr, flags /* & 1 OPT_BROADCAST */);
232
233 bb_debug_dump_packet(outpack, pktsize);
234
235 /* Fill in the source address, if possible. */
236 #ifdef __linux__
237 {
238 struct ifreq if_hwaddr;
239
240 strncpy_IFNAMSIZ(if_hwaddr.ifr_name, ifname);
241 ioctl_or_perror_and_die(s, SIOCGIFHWADDR, &if_hwaddr, "SIOCGIFHWADDR on %s failed", ifname);
242
243 memcpy(outpack+6, if_hwaddr.ifr_hwaddr.sa_data, 6);
244
245 # ifdef DEBUG
246 {
247 unsigned char *hwaddr = if_hwaddr.ifr_hwaddr.sa_data;
248 printf("The hardware address (SIOCGIFHWADDR) of %s is type %d "
249 "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x\n\n", ifname,
250 if_hwaddr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
251 hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
252 }
253 # endif
254 }
255 #endif /* __linux__ */
256
257 bb_debug_dump_packet(outpack, pktsize);
258
259 /* append the password if specified */
260 if (wol_passwd_sz > 0) {
261 memcpy(outpack+pktsize, wol_passwd, wol_passwd_sz);
262 pktsize += wol_passwd_sz;
263 }
264
265 bb_debug_dump_packet(outpack, pktsize);
266
267 /* This is necessary for broadcasts to work */
268 if (flags /* & 1 OPT_BROADCAST */) {
269 if (setsockopt_broadcast(s) != 0)
270 bb_perror_msg("SO_BROADCAST");
271 }
272
273 #if defined(PF_PACKET)
274 {
275 struct ifreq ifr;
276 strncpy_IFNAMSIZ(ifr.ifr_name, ifname);
277 xioctl(s, SIOCGIFINDEX, &ifr);
278 memset(&whereto, 0, sizeof(whereto));
279 whereto.sll_family = AF_PACKET;
280 whereto.sll_ifindex = ifr.ifr_ifindex;
281 /* The manual page incorrectly claims the address must be filled.
282 We do so because the code may change to match the docs. */
283 whereto.sll_halen = ETH_ALEN;
284 memcpy(whereto.sll_addr, outpack, ETH_ALEN);
285 }
286 #else
287 whereto.sa_family = 0;
288 strcpy(whereto.sa_data, ifname);
289 #endif
290 xsendto(s, outpack, pktsize, (struct sockaddr *)&whereto, sizeof(whereto));
291 if (ENABLE_FEATURE_CLEAN_UP)
292 close(s);
293 return EXIT_SUCCESS;
294 }
295