C++ 判断主机是否处于联网状态下

水深无声 2022-01-09 05:11 233阅读 0赞

直接让本机访问一个网站，如果成功的话，就说明成功联网，没有访问成功，则说明没有联网！！！

#include<iostream>
    #include <WINSOCK2.H>
    #pragma comment(lib,"ws2_32.lib")
    #define LEN 1024	//接收数据的大小
    using namespace std;
    
    
    int main()
    {
    	//加载套接字库
    	WORD wVersionRequested;
    	WSADATA wsaData;
    	int err;
    	
    	wVersionRequested = MAKEWORD( 1, 1 );    //初始化Socket动态连接库,请求1.1版本的winsocket库
    	
    	err = WSAStartup( wVersionRequested, &wsaData );
    	if ( err != 0 ) {
    		return 0;
    	}
    
    	if ( LOBYTE( wsaData.wVersion ) != 1 ||   //判断请求的winsocket是不是1.1的版本
            HIBYTE( wsaData.wVersion ) != 1 ) {
    		WSACleanup( );			//清盘
    		return 0;					//终止对winsocket使用
    	}
    	//WSADATA ws;
    	//WSAStartup(MAKEWORD(2,2),&ws);//
    	char http[60] = "www.google.com";			//访问谷歌网页
    	SOCKET sock = socket(AF_INET,SOCK_STREAM,0);//建立socket
    	if (sock == INVALID_SOCKET)
    	{
    		cout<<"建立访问socket套接字失败!"<<endl;
    		return 0;
    	}
    	sockaddr_in hostadd;
    	hostent* host = gethostbyname(http);//取得主机的IP地址
    	if(host==NULL)
    	{
    		cout<<"主机处于没有联网状态;"<<endl;
    		return 0;
    	}
    	cout<<"主机处于联网状态，现在可以进行通信!"<<endl;
    	memcpy(&hostadd,host->h_addr,sizeof(hostadd));//将返回的IP信息Copy到地址结构
    	hostadd.sin_family = AF_INET;
    	hostadd.sin_port = htons(80);
    	
    	
    	char buf[LEN]="GET / HTTP/1.1\r\nHost: ";//构造Http请求数据包
    	strcat(buf,inet_ntoa(hostadd.sin_addr));
    	strcat(buf," \r\nContent-Length: 10\r\n\r\n");
    	strcat(buf,"Connection:close");
    	
    	
    	int time = 1000;	//超时时间
    	setsockopt(sock,SOL_SOCKET,SO_RCVTIMEO,(char*)&time,sizeof(time));
    	
    	
    	if (connect(sock,(sockaddr*)&hostadd,sizeof(hostadd)) == SOCKET_ERROR)//连接请求
    	{
    		cout<<"与网页建立连接失败!"<<endl;
    		return 0;
    	}
    	if (SOCKET_ERROR == send(sock,buf,strlen(buf)+1,0))//发送构造好的Http请求包
    	{
    		cout<<"发送数据包失败!"<<endl;
    		return 0;
    	}
    	memset(buf,0,LEN);
    	recv(sock,buf,LEN,0);				//接收返回的数据
    	cout<<"从网页中获取的数据为:"<<buf;
    	closesocket(sock);
    	WSACleanup();
    return 0;
    }