WinSock客户端连接

Question

I have problem with this code if I use in client and server local IP it works but if I use in client 109.95.202.122 IP and in server INADDR_ANY it doesn't I was trying this on two computers but this still not working please help me.

Client

#include <iostream>
#include <winsock2.h>
#pragma comment(lib,"ws2_32.lib")

int main(void)
{
    WSADATA WsaDat;
    if(WSAStartup(MAKEWORD(2,2),&WsaDat)!=0)
    {
        std::cout<<"Winsock error - Winsock initialization failed\r\n";
        WSACleanup();
        system("PAUSE");
        return 0;
    }

    // Create our socket

    SOCKET Socket=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    if(Socket==INVALID_SOCKET)
    {
        std::cout<<"Winsock error - Socket creation Failed!\r\n";
        WSACleanup();
        system("PAUSE");
        return 0;
    }

    // Resolve IP address for hostname
    struct hostent *host;
    if((host=gethostbyname("109.95.202.122"))==NULL)
    {
        std::cout<<"Failed to resolve hostname.\r\n";
        WSACleanup();
        system("PAUSE");
        return 0;
    }

    // Setup our socket address structure
    SOCKADDR_IN SockAddr;
    SockAddr.sin_port=htons(8888);
    SockAddr.sin_family=AF_INET;
    SockAddr.sin_addr.s_addr=*((unsigned long*)host->h_addr);

    // Attempt to connect to server
    if(connect(Socket,(SOCKADDR*)(&SockAddr),sizeof(SockAddr))!=0)
    {
        std::cout<<"Failed to establish connection with server\r\n";
        WSACleanup();
        system("PAUSE");
        return 0;
    }

    // If iMode!=0, non-blocking mode is enabled.
    u_long iMode=1;
    ioctlsocket(Socket,FIONBIO,&iMode);

    // Main loop
    for(;;)
    {
        // Display message from server
        char buffer[1000];
        memset(buffer,0,999);
        int inDataLength=recv(Socket,buffer,1000,0);
        std::cout<<buffer;

        int nError=WSAGetLastError();
        if(nError!=WSAEWOULDBLOCK&&nError!=0)
        {
            std::cout<<"Winsock error code: "<<nError<<"\r\n";
            std::cout<<"Server disconnected!\r\n";
            // Shutdown our socket
            shutdown(Socket,SD_SEND);

            // Close our socket entirely
            closesocket(Socket);

            break;
        }
        Sleep(1000);
    }

    WSACleanup();
    system("PAUSE");
    return 0;
}

Server

#include <iostream>
#include <winsock2.h>
#pragma comment(lib,"ws2_32.lib")

int main()
{
    WSADATA WsaDat;
    if(WSAStartup(MAKEWORD(2,2),&WsaDat)!=0)
    {
        std::cout<<"WSA Initialization failed!\r\n";
        WSACleanup();
        system("PAUSE");
        return 0;
    }

    SOCKET Socket=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    if(Socket==INVALID_SOCKET)
    {
        std::cout<<"Socket creation failed.\r\n";
        WSACleanup();
        system("PAUSE");
        return 0;
    }

    SOCKADDR_IN serverInf;
    serverInf.sin_family=AF_INET;
    serverInf.sin_addr.s_addr=INADDR_ANY;
    serverInf.sin_port=htons(8888);

    if(bind(Socket,(SOCKADDR*)(&serverInf),sizeof(serverInf))==SOCKET_ERROR)
    {
        std::cout<<"Unable to bind socket!\r\n";
        WSACleanup();
        system("PAUSE");
        return 0;
    }

    listen(Socket,1);

    SOCKET TempSock=SOCKET_ERROR;
    while(TempSock==SOCKET_ERROR)
    {
        std::cout<<"Waiting for incoming connections...\r\n";
        TempSock=accept(Socket,NULL,NULL);
    }

    // If iMode!=0, non-blocking mode is enabled.
    u_long iMode=1;
    ioctlsocket(Socket,FIONBIO,&iMode);

    Socket=TempSock;
    std::cout<<"Client connected!\r\n\r\n";

    // Main loop
    for(;;)
    {
        char *szMessage="Welcome to the server!\r\n";
        send(Socket,szMessage,strlen(szMessage),0);

        int nError=WSAGetLastError();
        if(nError!=WSAEWOULDBLOCK&&nError!=0)
        {
            std::cout<<"Winsock error code: "<<nError<<"\r\n";
            std::cout<<"Client disconnected!\r\n";

            // Shutdown our socket
            shutdown(Socket,SD_SEND);

            // Close our socket entirely
            closesocket(Socket);

            break;
        }

        Sleep(1000);
    }

    WSACleanup();
    system("PAUSE");
    return 0;
}

Answer 1

Just guessing, but I think your problem is the gethostbyname which from memory doesn't work with IP addresses. Maybe look into getaddrinfo ?