wake-on-lan

Wake-on-LAN简称WOL或WoL，我们一般将其称为“网络唤醒”、“远端唤醒”技术。
它的功能是让已经进入休眠状态或关机状态的电脑，透过局域网（多半为以太网）的另一端对其发令，使其从休眠状态唤醒、恢复成运作状态，或从关机状态转成开机状态。

该功能依赖软件和硬件。硬件就在于主板和网卡的支持，软件在于操作系统的电源管理器。

WOL协议

wol的是通过在局域网用udp口7或者9端口广播Magic Packet来实现的。

Magic Packet是一个广播帧（frame），在Magic Packet内，每次都会先有连续6个”FF”的前缀，即：FF FF FF FF FF FF，在连续6个”FF”后则开始带出MAC地址，有时还会带出4字节或6字节的密码，一旦经由网卡侦测、解读、研判（广播）Magic Packet的内容，内容中的MAC地址、密码若与电脑自身的地址、密码吻合，就会启动唤醒、开机的程序。

java实现

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public class WakeOnLan {

    public static final int PORT = 9;

    public static void main(String[] args) {

        if (args.length != 2) {
            System.out.println("Usage: java WakeOnLan <broadcast-ip> <mac-address>");
            System.out.println("Example: java WakeOnLan 192.168.0.255 00:0D:61:08:22:4A");
            System.out.println("Example: java WakeOnLan 192.168.0.255 00-0D-61-08-22-4A");
            System.exit(1);
        }

        String ipStr = args[0];
        String macStr = args[1];

        try {
            byte[] macBytes = getMacBytes(macStr);
            byte[] bytes = new byte[6 + 16 * macBytes.length];
            for (int i = 0; i < 6; i++) {
                bytes[i] = (byte) 0xff;
            }
            for (int i = 6; i < bytes.length; i += macBytes.length) {
                System.arraycopy(macBytes, 0, bytes, i, macBytes.length);
            }

            InetAddress address = InetAddress.getByName(ipStr);
            DatagramPacket packet = new DatagramPacket(bytes, bytes.length, address, PORT);
            DatagramSocket socket = new DatagramSocket();
            socket.send(packet);
            socket.close();

            System.out.println("Wake-on-LAN packet sent.");
        }
        catch (Exception e) {
            System.out.println("Failed to send Wake-on-LAN packet: + e");
            System.exit(1);
        }

    }

    private static byte[] getMacBytes(String macStr) throws IllegalArgumentException {
        byte[] bytes = new byte[6];
        String[] hex = macStr.split("(\\:|\\-)");
        if (hex.length != 6) {
            throw new IllegalArgumentException("Invalid MAC address.");
        }
        try {
            for (int i = 0; i < 6; i++) {
                bytes[i] = (byte) Integer.parseInt(hex[i], 16);
            }
        }
        catch (NumberFormatException e) {
            throw new IllegalArgumentException("Invalid hex digit in MAC address.");
        }
        return bytes;
    }


}

python的组件

python的awake组件已经实现这个功能，见https://pypi.org/project/awake/

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Usage: awake [options] MAC1 [MAC2 MAC3 MAC...]

    Options:
      --version             show program's version number and exit
      -h, --help            show this help message and exit
      -p PORT, --port=PORT  Destination port. (Default 9)
      -b BROADCAST, --broadcast=BROADCAST
                            Broadcast ip of the network. (Default 255.255.255.255)
      -d DESTINATION, --destination=DESTINATION
                            Destination ip/domain to connect and send the packet,
                            by default use broadcast.
      -f FILE, --file=FILE  Use a file with the list of macs, separated with -s,
                            by default \n. If any mac (line where -s \n), have the
                            "#" character, any following character is considered a
                            comment. Can be used multiple times for multiple
                            files.
      -s SEPARATOR, --separator=SEPARATOR
                            Pattern to be use as a separator with the -f option.
                            (Default \n)
      -q, --quiet           Do not output informative messages.

注意事项

如果用python的awake工具，记得要加sudo，不然提示是

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Sending magic packet to 255.255.255.255 with broadcast 255.255.255.255 MAC xx-xx-xx-xx-xx-xx port 9

但其实没有发送成功

参考

未分类
wake-on-lan
https://blog.fengcl.com/2018/09/11/wake-on-lan/
作者
frank
发布于
2018年9月11日
许可协议