.NET 简单实现广播

浅浅的花香味﹌ 2022-06-12 12:00 158阅读 0赞

代码
    
    Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->    class Program
        {
    
            static bool connecting = true;
            static void Main()
            {
                Received();
                while (connecting)
                {
                    string content = Console.ReadLine();
                    if (content.Length > 0)
                    {
                        if (string.Compare(content, "<Stop>", true) == 0)
                        {
                            Console.WriteLine("关闭...");
                            connecting = false;
                        }
                        else
                        {
                            Send(content);
                        }
                    }
                }
                Console.ReadKey();
            }
    
            public static void Send(string content)
            {
                Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
                //IPEndPoint iep1 = new IPEndPoint(IPAddress.Broadcast, 9050);//255.255.255.255 
                IPEndPoint iep2 = new IPEndPoint(IPAddress.Parse("192.168.100.255"), 9050);
               // string hostname = Dns.GetHostName();
                byte[] data = Encoding.ASCII.GetBytes(content);
                sock.SetSocketOption(SocketOptionLevel.Socket,
                SocketOptionName.Broadcast, 1);
                //sock.SendTo(data, iep1);
                sock.SendTo(data, iep2);
                sock.Close();
            }
    
            public static void Received()
            {
                ThreadPool.QueueUserWorkItem((x) =>
                {
                    Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
                    IPEndPoint iep = new IPEndPoint(IPAddress.Any, 9050);
                    sock.Bind(iep);
                    EndPoint ep = (EndPoint)iep;
    
                    byte[] data;
                    int recv;
                    string stringData;
                    Console.WriteLine("接听开启...");
                    while (connecting)
                    {
                        data = new byte[1024];
                        recv = sock.ReceiveFrom(data, ref ep);
                        stringData = Encoding.ASCII.GetString(data, 0, recv);
                        Console.WriteLine("信息: {0} 来自: {1}", stringData, ep.ToString());
                    }
                    Console.WriteLine("接听关闭...");
                    sock.Close();
                });
            }
    
        }

从原理角度考虑，广播和单向定点发送没什么区别，献上一段小代码（来自msdn），基本很详细的说了如何广播式发送udp数据包：

using   System;   
      using   System.Net;   
      using   System.Net.Sockets;   
      using   System.Text;   
        
      public   class   UDPMulticastSender   {   
        
              private   static   IPAddress   GroupAddress   =     
                      IPAddress.Parse("224.168.100.2");   
              private   static   int   GroupPort   =   11000;   
                
              private   static   void   Send(   String   message)   {   
                      UdpClient   sender   =   new   UdpClient();   
                      IPEndPoint   groupEP   =   new   IPEndPoint(GroupAddress,GroupPort);   
        
                      try   {   
                              Console.WriteLine("Sending   datagram   :   {0}",   message);   
                              byte[]   bytes   =   Encoding.ASCII.GetBytes(message);   
        
                              sender.Send(bytes,   bytes.Length,   groupEP);   
                                
                              sender.Close();   
                                
                      }   catch   (Exception   e)   {   
                              Console.WriteLine(e.ToString());   
                      }   
                        
              }   
        
              public   static   int   Main(String[]   args)   {   
                      Send(args[0]);   
        
                      return   0;   
              }

单播(点对点) 通信，即网络中单一的源节点发送封包到单一的上的节点。

在广播通信中， 网络层提供了将封包从一个节点发送到所有其他节点的服务。

利用广播(broadcast) 可以将数据发送给本地子网上的每个机器。广播的缺点是如果多个进程都发送广播数据， 网络就会阻塞。

1. 服务端

using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Net.Sockets;
    using System.Net;
    using System.Threading;
    
    namespace _5._2_广播通信
    {
        class Program
        {
            static void Main(string[] args)
            {
                Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
                s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, true);
    
                byte[] buffer = Encoding.Unicode.GetBytes("Hello World");
                IPEndPoint iep1 = new IPEndPoint(IPAddress.Broadcast, 4567);//255.255.255.255
    
                int i = 0;
                while (true)
                {
                    Console.WriteLine("正在进行广播 {0}", i++.ToString());
                    s.SendTo(buffer, iep1);
                    Thread.Sleep(5000);
                }
            }
        }
    }

对于UPD来说， 存在一个特定的广播地址 - 255.255.255.255， 广播数据都应该发送到这里。

广播消息的目的IP地址是一种特殊IP地址，称为广播地址。

广播地址由IP地址网络前缀加上全1主机后缀组成，如：192.168.1.255是 192.169.1.0 这个网络的广播地址;

130.168.255.255 是130.168.0.0 这个网络的广播地址。

向全部为1的IP地址（255.255.255.255）发送消息的话，那么理论上全世界所有的联网的计算机都能收得到了。

但实际上不是这样的，一般路由器上设置抛弃这样的包，只在本地网内广播，所以效果和向本地网的广播地址发送消息是一样的。

进行广播通信， 必须打开广播选项 SO\_BROADCAST

2. 客户端

using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Net.Sockets;
    using System.Net;
    
    namespace Client
    {
    class Program
     {
    static void Main(string[] args)
     {
     Socket m_s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
    
     IPEndPoint iep = new IPEndPoint(IPAddress.Any, 4567);
     EndPoint ep = (EndPoint)iep;
     m_s.Bind(iep);
    
    byte[] buffer = new byte[1204];
    while (true)
     {
    int revc = m_s.ReceiveFrom(buffer, ref ep);
    if (revc > 0)
     {
    string data = Encoding.Unicode.GetString(buffer, 0, revc);
     Console.WriteLine(data);
     }
     }
     }
     }
    }

3. 效果

![2010070808144712.jpg][]

C\#实现局域网UDP广播,这一块设置到局域网，需要用到的主要命名空间是:System.Net和System.Net.Scoket:

接收端:

![None.gif][] Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);//初始化一个Scoket协议  
![None.gif][]  
![None.gif][] IPEndPoint iep = new IPEndPoint(IPAddress.Any, 9095);//初始化一个侦听局域网内部所有IP和指定端口  
![None.gif][]  
![None.gif][] EndPoint ep = (EndPoint)iep;  
![None.gif][]  
![None.gif][] socket.Bind(iep);//绑定这个实例  
![None.gif][]  
![None.gif][] while (true)  
 \{  
byte\[\] buffer = new byte\[1024\];//设置缓冲数据流  
  
socket.ReceiveFrom(buffer, ref ep);//接收数据,并确把数据设置到缓冲流里面  
  
 Console.WriteLine(Encoding.Unicode.GetString(buffer2).TrimEnd('/u0000') + " " + DateTime.Now.ToString());

发送端:

![None.gif][] Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);//初始化一个Scoket实习,采用UDP传输  
![None.gif][]  
![None.gif][] IPEndPoint iep = new IPEndPoint(IPAddress.Broadcast, 9095);//初始化一个发送广播和指定端口的网络端口实例  
![None.gif][]  
![None.gif][] sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1);//设置该scoket实例的发送形式  
![None.gif][]  
![None.gif][] string request = "你好,TEST SEND!";//初始化需要发送而的发送数据  
![None.gif][]  
![None.gif][] byte\[\] buffer = Encoding.Unicode.GetBytes(request);  
![None.gif][]  
![None.gif][] sock.SendTo(buffer, iep);  
![None.gif][]  
![None.gif][] sock.Close();

[2010070808144712.jpg]: /images/20220612/ab6e3f814d4a40ebbf7f6d657d92d0fc.png
[None.gif]: /images/20220612/ec59fd625e284abcb7724377ecc950b0.png