.NET 简单实现广播
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();