發送UDP廣播，需要接收來自所有客戶端的消息

我正在開發客戶端需要連接的服務器應用程序。但我不希望我的用戶輸入的IP地址......我想客戶發現的所有服務器上的端口4800上運行（對我來說）發送UDP廣播，需要接收來自所有客戶端的消息

這裏是我的服務器代碼：

public partial class Form1 : Form 
{ 
    public Form1() 
    { 
     InitializeComponent(); 
    } 
    static ThreadStart ts = new ThreadStart(start_server); 
    Thread thread = new Thread(ts); 
    private void Form1_Load(object sender, EventArgs e) 
    { 


     thread.Start(); 
    } 

    private static void start_server() 
    { 
     //Start server 
     Socket server = new Socket(AddressFamily.InterNetwork, 
     SocketType.Dgram, ProtocolType.Udp); 
     Console.Write("Running server..." + Environment.NewLine); 
     server.Bind(new IPEndPoint(IPAddress.Any, 4800)); 

     while (true) 
     { 
      IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0); 
      EndPoint tempRemoteEP = (EndPoint)sender; 
      byte[] buffer = new byte[1000]; 
      //Recive message from anyone. 
      server.ReceiveFrom(buffer, ref tempRemoteEP); 

      Console.Write("Server got '" + Encoding.ASCII.GetString(buffer).TrimEnd(new char[] { (char)0 }) + 
      "' from " + tempRemoteEP.ToString() + 
      Environment.NewLine); 
      string access_code = Encoding.ASCII.GetString(buffer).TrimEnd(new char[] { (char)0 }); 
      if (access_code == "7uz876t5r798qwe12") 
      { 
       Console.Write("Sending Response to " + tempRemoteEP.ToString() + 
       Environment.NewLine); 

       //Replay to client 

       server.SendTo(Encoding.ASCII.GetBytes("ACCESS GRANTED"), 
       tempRemoteEP); 
      } 
      else 
      { 
       Console.WriteLine("Client Access denied!"); 
       server.SendTo(Encoding.ASCII.GetBytes("ACCESS DENIED"), 
       tempRemoteEP); 
      } 

     } 
    } 

    private void Form1_FormClosing(object sender, FormClosingEventArgs e) 
    { 
     Environment.Exit(Environment.ExitCode); 
    } 
}

而這就是我的客戶端發送一個UDP廣播：

public partial class Form1 : Form 
{ 
    public Form1() 
    { 
     InitializeComponent(); 
    } 

    private void Form1_Load(object sender, EventArgs e) 
    { 

    } 
    Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, 
     ProtocolType.Udp); 
    private void button1_Click(object sender, EventArgs e) 
    { 



     IPEndPoint AllEndPoint = new IPEndPoint(IPAddress.Broadcast, 4800); 

     //Allow sending broadcast messages 
     client.SetSocketOption(SocketOptionLevel.Socket, 
     SocketOptionName.Broadcast, 1); 

     //Send message to everyone 
     client.SendTo(Encoding.ASCII.GetBytes("7uz876t5r798qwe12"), AllEndPoint); 
     Console.Write("Client send '1' to " + AllEndPoint.ToString() + 
     Environment.NewLine); 

     IPEndPoint _sender = new IPEndPoint(IPAddress.Any, 0); 
     EndPoint tempRemoteEP = (EndPoint)_sender; 
     byte[] buffer = new byte[1000]; 

     string serverIp; 
     try 
     { 

      client.SetSocketOption(SocketOptionLevel.Socket, 
      SocketOptionName.ReceiveTimeout, 3000); 
      client.ReceiveFrom(buffer, ref tempRemoteEP); 
      Console.Write("Client got '" + buffer[0] + "' from " + 
      tempRemoteEP.ToString() + Environment.NewLine); 
      MessageBox.Show(Encoding.ASCII.GetString(buffer).TrimEnd(new char[] { (char)0 })); 
      //Get server IP (ugly) 
      serverIp = tempRemoteEP.ToString().Split(":".ToCharArray(), 2)[0]; 
      listServer.Items.Add(serverIp); 

     } 
     catch (Exception ex) 
     { 
      //Timout. No server answered. 
      MessageBox.Show(ex.Message); 
     } 

     // MessageBox.Show(serverIp); 
    } 

}

所有服務器上運行的是接收廣播，但我的客戶只接收1個IP地址。也許到達客戶端的第一個響應？

我如何能夠發現我的端口上正在監聽的所有服務器？

來源

2016-06-15 Knoffel

UDP並不能保證到達。通常情況下，您會發出廣播，並且事情會有所反應。您可以採取第一個選項，以免等待其他人，或等待給定的時間，讓他們選擇他們想要的。 – BugFinder

您的客戶只撥打ReceiveFrom()一次，所以它只會收到一個響應。您需要在循環中調用ReceiveFrom()，然後運行循環幾秒鐘，以使多個服務器有足夠的時間響應。

來源

2016-06-15 14:57:43

發送UDP廣播，需要接收來自所有客戶端的消息

回答

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