Discovery ifdown/ifup on all OS; by QNetworkInterface

I Knitting this piece of code to discovery if client is Connected to Network...
But how i can check if gateway && dns resolve correct?
similar to php http://php.net/gethostbyname or http://php.net/dns_get_mx
without Qprocess host dig ....

Code:

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static inline bool NetworkEnable() {
 
    bool validip = false;
    QList<QHostAddress> addrlist = QNetworkInterface::allAddresses();
    int o = -1;
    foreach(QHostAddress addr, addrlist){
    o++;
    QNetworkInterface hop = QNetworkInterface::interfaceFromIndex(o);
    QString mach = hop.hardwareAddress(); 
    QString name = hop.name();
    QString oneip = addr.toString();
        if (!oneip.contains("127.")) {
         bool actual = hop.isValid();
            if (actual) {
             validip = true;  
            }
         ////////qDebug() << "flags -> " <<  hop.flags();
         //////////qDebug() << "pi -> " << oneip << " valid ->" << validip << " MACADRESS->" << mach << " name ->" << name;
        }
    }
   //////qDebug() << "validip -> " <<  validip;
return validip;
}

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