.NET 简单实现广播

来源：互联网发布：二战苏德实力对比知乎编辑：程序博客网时间：2024/05/18 13:30

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

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:

Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);//初始化一个Scoket协议

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

EndPoint ep = (EndPoint)iep;

socket.Bind(iep);//绑定这个实例

            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:

Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);//初始化一个Scoket实习,采用UDP传输

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

sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1);//设置该scoket实例的发送形式

string request = "你好,TEST SEND!";//初始化需要发送而的发送数据

byte[] buffer = Encoding.Unicode.GetBytes(request);

sock.SendTo(buffer, iep);

sock.Close();