学步园

相比TCP，UDP的优点是传输速度快且能对整个网络广播数据。但我以前在使用UDP整个网络广播数据的用法上，一直没能好好使用。这段时间，正好需要使用UDP的这个功能，因此经过摸索，得出了一种使用方法如下：（不一定是最好的，但能实现我的功能）

// 服务器端<br /> // Server.cpp : Defines the entry point for the console application.<br /> //</p> <p>#include "stdafx.h"<br /> #include <WinSock2.h><br /> #include <stdio.h><br /> #include <iostream><br /> using namespace std;</p> <p>#pragma comment(lib, "ws2_32.lib")</p> <p>const int MAX_BUF_LEN = 255;</p> <p>int _tmain(int argc, _TCHAR* argv[])<br /> {<br /> WORD wVersionRequested;<br /> WSADATA wsaData;<br /> int err;</p> <p> // 启动socket api<br /> wVersionRequested = MAKEWORD( 2, 2 );<br /> err = WSAStartup( wVersionRequested, &wsaData );<br /> if ( err != 0 )<br /> {<br /> return -1;<br /> }</p> <p> if ( LOBYTE( wsaData.wVersion ) != 2 ||<br /> HIBYTE( wsaData.wVersion ) != 2 )<br /> {<br /> WSACleanup( );<br /> return -1;<br /> }</p> <p> // 创建socket<br /> SOCKET connect_socket;<br /> connect_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);<br /> if(INVALID_SOCKET == connect_socket)<br /> {<br /> err = WSAGetLastError();<br /> printf("/"socket/" error! error code is %d/n", err);<br /> return -1;<br /> }</p> <p> SOCKADDR_IN sin;<br /> sin.sin_family = AF_INET;<br /> sin.sin_port = htons(3779);<br /> sin.sin_addr.s_addr = INADDR_BROADCAST;</p> <p> bool bOpt = true;<br /> //设置该套接字为广播类型<br /> setsockopt(connect_socket, SOL_SOCKET, SO_BROADCAST, (char*)&bOpt, sizeof(bOpt));</p> <p> int nAddrLen = sizeof(SOCKADDR);</p> <p> char buff[MAX_BUF_LEN] = "";<br /> int nLoop = 0;<br /> while(1)<br /> {<br /> nLoop++;<br /> sprintf(buff, "%8d", nLoop);</p> <p> // 发送数据<br /> int nSendSize = sendto(connect_socket, buff, strlen(buff), 0, (SOCKADDR*)&sin, nAddrLen);<br /> if(SOCKET_ERROR == nSendSize)<br /> {<br /> err = WSAGetLastError();<br /> printf("/"sendto/" error!, error code is %d/n", err);<br /> return -1;<br /> }<br /> printf("Send: %s/n", buff);<br /> Sleep(500);<br /> }</p> <p> return 0;<br /> }</p> <p>// 客户端<br /> // Client.cpp : Defines the entry point for the console application.<br /> //</p> <p>#include "stdafx.h"<br /> #include <WinSock2.h><br /> #include <stdio.h></p> <p>#pragma comment(lib, "ws2_32.lib")</p> <p>const int MAX_BUF_LEN = 255;</p> <p>int _tmain(int argc, _TCHAR* argv[])<br /> {<br /> WORD wVersionRequested;<br /> WSADATA wsaData;<br /> int err;</p> <p> // 启动socket api<br /> wVersionRequested = MAKEWORD( 2, 2 );<br /> err = WSAStartup( wVersionRequested, &wsaData );<br /> if ( err != 0 )<br /> {<br /> return -1;<br /> }</p> <p> if ( LOBYTE( wsaData.wVersion ) != 2 || HIBYTE( wsaData.wVersion ) != 2 )<br /> {<br /> WSACleanup( );<br /> return -1;<br /> }</p> <p> // 创建socket<br /> SOCKET connect_socket;<br /> connect_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);<br /> if(INVALID_SOCKET == connect_socket)<br /> {<br /> err = WSAGetLastError();<br /> printf("/"socket/" error! error code is %d/n", err);<br /> return -1;<br /> }</p> <p> // 用来绑定套接字<br /> SOCKADDR_IN sin;<br /> sin.sin_family = AF_INET;<br /> sin.sin_port = htons(3779);<br /> sin.sin_addr.s_addr = 0;</p> <p> // 用来从网络上的广播地址接收数据<br /> SOCKADDR_IN sin_from;<br /> sin_from.sin_family = AF_INET;<br /> sin_from.sin_port = htons(3779);<br /> sin_from.sin_addr.s_addr = INADDR_BROADCAST;</p> <p> //设置该套接字为广播类型，<br /> bool bOpt = true;<br /> setsockopt(connect_socket, SOL_SOCKET, SO_BROADCAST, (char*)&bOpt, sizeof(bOpt));</p> <p> // 绑定套接字<br /> err = bind(connect_socket, (SOCKADDR*)&sin, sizeof(SOCKADDR));<br /> if(SOCKET_ERROR == err)<br /> {<br /> err = WSAGetLastError();<br /> printf("/"bind/" error! error code is %d/n", err);<br /> return -1;<br /> }</p> <p> int nAddrLen = sizeof(SOCKADDR);<br /> char buff[MAX_BUF_LEN] = "";<br /> int nLoop = 0;<br /> while(1)<br /> {<br /> // 接收数据<br /> int nSendSize = recvfrom(connect_socket, buff, MAX_BUF_LEN, 0, (SOCKADDR*)&sin_from, &nAddrLen);<br /> if(SOCKET_ERROR == nSendSize)<br /> {<br /> err = WSAGetLastError();<br /> printf("/"recvfrom/" error! error code is %d/n", err);<br /> return -1;<br /> }<br /> buff[nSendSize] = '/0';<br /> printf("Recv: %s/n", buff);<br /> }</p> <p> return 0;<br /> }</p> <p>