实现SOCKET转发的核心程序

int DataSend(SOCKET s, char *DataBuf, int DataLen)//将DataBuf中的DataLen个字节发到s去  
{  
    int nBytesLeft = DataLen;  
    int nBytesSent = 0;  
    int ret;  
    //set socket to blocking mode  
    int iMode = 0;  
    ioctlsocket(s, FIONBIO, (u_long FAR*) &iMode);  
    while(nBytesLeft > 0)  
    {  
        ret = send(s, DataBuf + nBytesSent, nBytesLeft, 0);  
        if(ret <= 0)  
            break;  
        nBytesSent += ret;  
        nBytesLeft -= ret;  
    }  
    return nBytesSent;  
}  

int PipeThiread(int i)//在两个SOCKET中进行数据转发  
{  

    char RecvBuf[MAXBUFFER] = {0};  
    fd_set Fd_Read;  
    int ret, nRecv;  

    while(1)  
    {  
        FD_ZERO(&Fd_Read);  
        FD_SET(H_SERVER_PIPE_LIST[i].Client, &Fd_Read);  
        FD_SET(H_SERVER_PIPE_LIST[i].Server, &Fd_Read);  
        ret = select(0, &Fd_Read, NULL, NULL, NULL);  
        if(ret <= 0)  
            PipeDATA_Close(i);
        if(FD_ISSET(H_SERVER_PIPE_LIST[i].Client, &Fd_Read))  
        {  
            nRecv = recv(H_SERVER_PIPE_LIST[i].Client, RecvBuf, sizeof(RecvBuf), 0);  
            if(nRecv <= 0)  
                PipeDATA_Close(i);
            ret = DataSend(H_SERVER_PIPE_LIST[i].Server, RecvBuf, nRecv);  
            if(ret == 0 || ret != nRecv)  
                PipeDATA_Close(i);
        }  
        if(FD_ISSET(H_SERVER_PIPE_LIST[i].Server, &Fd_Read))  
        {  
            nRecv = recv(H_SERVER_PIPE_LIST[i].Server, RecvBuf, sizeof(RecvBuf), 0);  
            if(nRecv <= 0)  
                PipeDATA_Close(i);
            ret = DataSend(H_SERVER_PIPE_LIST[i].Client, RecvBuf, nRecv);  
            if(ret == 0 || ret != nRecv)  
                PipeDATA_Close(i);
        }  
    }  
    return 0;  
}