busybox/networking/ether-wake.c

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/* 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"
*
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* 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"
*
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* 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"
*
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* 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.
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*
* 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 "busybox.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) puts("");
}
printf("\n\n");
}
#else
# define bb_debug_msg(fmt, args...)
# define bb_debug_dump_packet(outpack, pktsize)
#endif
static inline void get_dest_addr(const char *arg, struct ether_addr *eaddr);
static inline int get_fill(unsigned char *pkt, struct ether_addr *eaddr, int broadcast);
static inline int get_wol_pw(const char *ethoptarg, unsigned char *wol_passwd);
int ether_wake_main(int argc, char *argv[])
{
char *ifname = "eth0", *pass = NULL;
unsigned long 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 */
flags = getopt32(argc, argv, "bi:p:", &ifname, &pass);
if (optind == argc)
bb_show_usage();
if (pass)
wol_passwd_sz = get_wol_pw(pass, wol_passwd);
/* create the raw socket */
s = make_socket();
/* now that we have a raw socket we can drop root */
xsetuid(getuid());
/* 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;
strcpy(if_hwaddr.ifr_name, ifname);
if (ioctl(s, SIOCGIFHWADDR, &if_hwaddr) < 0)
bb_perror_msg_and_die("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]*/) {
int one = 1;
if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, (void *)&one, sizeof(one)) < 0)
bb_perror_msg("SO_BROADCAST");
}
#if defined(PF_PACKET)
{
struct ifreq ifr;
strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
if (ioctl(s, SIOCGIFINDEX, &ifr) == -1)
bb_perror_msg_and_die("SIOCGIFINDEX");
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
if (sendto(s, outpack, pktsize, 0, (struct sockaddr *)&whereto, sizeof(whereto)) < 0)
bb_perror_msg(bb_msg_write_error);
close(s);
return EXIT_SUCCESS;
}
/* Convert the host ID string to a MAC address.
* The string may be a:
* Host name
* IP address string
* MAC address string
*/
static inline 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));
#else
# warning Need to implement ether_hostton() for uClibc
#endif
} else
bb_show_usage();
}
static inline int get_fill(unsigned char *pkt, struct ether_addr *eaddr, int broadcast)
{
int offset, i;
unsigned char *station_addr = eaddr->ether_addr_octet;
if (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;
}
return offset;
}
static inline int get_wol_pw(const char *ethoptarg, unsigned char *wol_passwd)
{
int 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 */
if (byte_cnt < 4)
byte_cnt = sscanf(ethoptarg, "%d.%d.%d.%d",
&passwd[0], &passwd[1], &passwd[2], &passwd[3]);
if (byte_cnt < 4) {
bb_error_msg("cannot read Wake-On-LAN pass");
return 0;
}
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;
}