Wake-On-LAN

wol.c

// Portable Wake-On-Lan by Lionello Lunesu, placed in the public domain
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#ifdef _MSC_VER
#pragma comment(lib, "ws2_32.lib")
#endif
#else
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <errno.h>
typedef unsigned char BYTE;
typedef char TCHAR;
typedef int BOOL;
typedef int SOCKET;
#endif
#include <stdio.h>

#define MACLEN (6)
#define PACKLEN (17*MACLEN)

int H2I(TCHAR m) {
  return m <= '9' ? m - '0' : (m | 32) - 'a' + 10;
}

BOOL ValidHex(TCHAR t) {
	return (t >= '0' && t <= '9') || (t >= 'a' && t <= 'f') || (t >= 'A' && t <= 'F');
}

int main(int argc, char* argv[])
{
#ifdef _WIN32
	WSADATA wsaData;
#endif
	const char* pMac = (argc >= 2 ? argv[1] : NULL);
	const char* pIp = (argc == 3 ? argv[2] : NULL);
	struct sockaddr_in addr;
	int t = 0, i;
	SOCKET sock;
	TCHAR nibble1, nibble2;
	BOOL BroadCast = 1;
	char pack[PACKLEN];

	if (pMac == NULL) {
		printf("Usage: wol <MAC> [IP]\n");
		return -3;
	}

	// FFFFFFFFFFFF
	while (t < MACLEN)
		pack[t++] = 0xFF;

	// first MAC
	for (i=0; t < MACLEN+MACLEN; ++i) {
		nibble1 = pMac[i];
		if (nibble1 == 0)
			break;
		if (!ValidHex(nibble1))
			continue;
		nibble2 = pMac[++i];
		if (!ValidHex(nibble2))
			break;
		pack[t++] = (H2I(nibble1) << 4) | H2I(nibble2);
	}

	if (t < MACLEN+MACLEN)
	{
		printf("Could not parse MAC address\n");
		return -2;
	}

	// repeat 15 more times
	for (;t < PACKLEN; ++t)
		pack[t] = pack[t - MACLEN];

	addr.sin_addr.s_addr = ~0;
#ifdef _WIN32
	// Initialize Winsock
	i = WSAStartup(MAKEWORD(2,2), &wsaData);
	if (i != 0) {
		printf("WSAStartup failed: %d\n", i);
		return i;
	}

	if (pIp && InetPton(AF_INET, pIp, &addr) <= 0)
	{
		printf("Could not parse IP address\n");
		return WSAGetLastError();
	}
#else
	if (pIp && inet_pton(AF_INET, pIp, &addr) <= 0)
	{
		printf("Could not parse IP address\n");
		return errno;
	}
#endif

	sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
#ifdef _WIN32
	if (sock == INVALID_SOCKET) {
		i = WSAGetLastError();
	}
#else
	if (sock < 0) {
		i = errno;
	}
#endif
	else {
		i = setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (const char*)&BroadCast, sizeof(BroadCast));

		addr.sin_family = AF_INET;
		addr.sin_port = htons(9);	// network byte order
		t = sendto(sock, pack, PACKLEN, 0, (struct sockaddr*)&addr, sizeof(addr));
#ifdef _WIN32
		if (t != PACKLEN)
			i = WSAGetLastError();
		closesocket(sock);
#else
		if (t != PACKLEN)
			i = errno;
		close(sock);
#endif
	}

#ifdef _WIN32
	WSACleanup();
#endif
	return i;
}