C++实现获取NPT网络时间

.     最近有个项目需要这个功能。网络上大部分找的一些对于年份获取的结果有错误。。不过还是从网络上得到了资料实现了功能。发出来给需要用到的人吧。。

注释的代码是初始化网络的代码，返回值st就获取到的网络时间了。

//从网络获取是否处于合法时间
EXPORT BOOL GetValidityTime()
{
    ULONG ulTime = 0;
    SYSTEMTIME st;
    BOOL bRet = TRUE;

    //InitSocket();
    if (GetNETTime(&ulTime) == TRUE)
    {
        st = UpTimer(ulTime);
    }
    else
    {
        bRet = FALSE;
        ::MessageBox(NULL, L"网络时间获取失败,请保证使用时网络通畅.", NULL, MB_OK);
    }

    return bRet;
}

//获取网络时间
BOOL GetNETTime(ULONG *ulData)
{
    BOOL bRet = TRUE;

    SOCKET s = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (s == INVALID_SOCKET)
    {
        ::MessageBox(NULL, L"创建socket失败!\n", NULL, MB_OK);
        bRet = FALSE;
        goto _Exit;
    }

    sockaddr_in sin;
    sin.sin_family = AF_INET;
    sin.sin_port = htons(37);
    sin.sin_addr.S_un.S_addr = inet_addr("132.163.4.101"); 
    if (connect(s,(sockaddr*)&sin,sizeof(sin)) == -1)
    {
        ::MessageBox(NULL, L"连接失败!\n", NULL, MB_OK);
        bRet = FALSE;
        goto _Exit;
    }

    ULONG ulTime = 0;
    int nLength = sizeof(sin);
    int nRecv = ::recv(s, (char*)&ulTime, sizeof(ulTime), 0);
    if (nRecv != 0 && nRecv != SOCKET_ERROR)
    {
        *ulData = ntohl(ulTime);//转换为从TCP / IP网络为u_long到主机字节顺序
    }
    else
    {
        ::MessageBox(NULL, L"服务器不能确定当前时间!\n", NULL, MB_OK);
        bRet = FALSE;
        goto _Exit;
    }

_Exit:
    if (s != INVALID_SOCKET)
    {
        ::closesocket(s);
    }
        
    return bRet;
}

#define HIGHTIME 21968699 // 21968708 // Jan 1, 1900 FILETIME.highTime
#define LOWTIME 4259332096 // 1604626432 // Jan 1, 1900 FILETIME.lowtime

SYSTEMTIME UpTimer(ULONG ulTime)
{
    FILETIME ft = {0};
    SYSTEMTIME st = {0};

    st.wYear = 1900;
    st.wMonth = 1;
    st.wDay = 1;
    st.wMonth = 0;
    st.wMinute = 0;
    st.wSecond = 0;
    st.wMilliseconds = 0;

    UINT64 uiCurTime, uiBaseTime, uiResult;
    uiBaseTime = ((UINT64) HIGHTIME << 32) + LOWTIME;
    uiCurTime = (UINT64)ulTime * (UINT64)10000000;
    uiResult = uiBaseTime + uiCurTime;
    FileTimeToSystemTime((LPFILETIME)&uiResult, &st);
    return st;
}