在C#中通过MAC Ping或以其他方式告知设备是否在网络上

Question

我正在开发一个家庭安全应用程序.我想做的一件事是根据我是否在家里自动关闭它.我有一部带Wifi的手机,当我回家时,它会自动连接到我的网络.

手机通过DHCP连接并获取其地址.虽然我可以将其配置为使用静态IP,但我宁愿不这样做.在C#/ .Net中是否有任何类型的"Ping"或等效设备可以获取设备的MAC地址并告诉我它是否在网络上当前有效？

编辑:为了澄清,我正在PC上运行软件,我希望能够在同一局域网上检测到手机.

编辑:这是我想出的代码,感谢spoulson的帮助.它可靠地检测我感兴趣的任何手机是否在家中.

private bool PhonesInHouse()
{

    Ping p = new Ping();
    // My home network is 10.0.23.x, and the DHCP 
    // pool runs from 10.0.23.2 through 10.0.23.127.

    int baseaddr = 10;
    baseaddr <<= 8;
    baseaddr += 0;
    baseaddr <<= 8;
    baseaddr += 23;
    baseaddr <<= 8;

    // baseaddr is now the equivalent of 10.0.23.0 as an int.

    for(int i = 2; i<128; i++) {
        // ping every address in the DHCP pool, in a separate thread so 
        // that we can do them all at once
        IPAddress ip = new IPAddress(IPAddress.HostToNetworkOrder(baseaddr + i));
        Thread t = new Thread(() => 
             { try { Ping p = new Ping(); p.Send(ip, 1000); } catch { } });
        t.Start();
    }

    // Give all of the ping threads time to exit

    Thread.Sleep(1000);

    // We're going to parse the output of arp.exe to find out 
    // if any of the MACs we're interested in are online

    ProcessStartInfo psi = new ProcessStartInfo();
    psi.Arguments = "-a";
    psi.FileName = "arp.exe";
    psi.RedirectStandardOutput = true;
    psi.UseShellExecute = false;
    psi.CreateNoWindow = true;

    bool foundone = false;
    using (Process pro = Process.Start(psi))
    {
        using (StreamReader sr = pro.StandardOutput)
        {
            string s = sr.ReadLine();

            while (s != null)
            {
                if (s.Contains("Interface") || 
                    s.Trim() == "" || 
                    s.Contains("Address"))
                {
                    s = sr.ReadLine();
                    continue;
                }
                string[] parts = s.Split(new char[] { ' ' }, 
                    StringSplitOptions.RemoveEmptyEntries);

                // config.Phones is an array of strings, each with a MAC 
                // address in it.
                // It's up to you to format them in the same format as 
                // arp.exe
                foreach (string mac in config.Phones)
                {
                    if (mac.ToLower().Trim() == parts[1].Trim().ToLower())
                    {
                        try
                        {
                            Ping ping = new Ping();
                            PingReply pingrep = ping.Send(parts[0].Trim());
                            if (pingrep.Status == IPStatus.Success)
                            {
                                foundone = true;
                            }
                        }
                        catch { }
                        break;
                    }
                }
                s = sr.ReadLine();
            }
        }
    }

    return foundone;
}

Answer 1

一种不同的方法是使用ping和arp工具。由于 ARP 数据包只能保留在同一个广播域中，因此您可以 ping 网络的广播地址，每个客户端都会回复 ARP 响应。这些响应中的每一个都缓存在您的 ARP 表中，您可以使用命令查看该表arp -a。所以概要：

rem Clear ARP cache
netsh interface ip delete arpcache

rem Ping broadcast addr for network 192.168.1.0
ping -n 1 192.168.1.255

rem View ARP cache to see if the MAC addr is listed
arp -a

其中一些可以在托管代码中完成，例如在System.Net.NetworkInformation命名空间中。

注意：通过清除其他本地服务器的缓存条目，清除 ARP 缓存可能会对网络性能产生轻微影响。然而，无论如何，缓存通常每 20 分钟或更短时间就会被清除一次。