#include <usb.h>

    QList<QString> eligableInterfaces;

    usb_init();

    usb_find_busses();

    usb_find_devices();

    for (struct usb_bus *bus = usb_get_busses(); bus; bus = bus->next) {

        for (struct usb_device *device = bus->devices; device; device = device->next) {

            for (int n = 0; n < device->descriptor.bNumConfigurations; ++n) {

                struct usb_config_descriptor &usbConfig =device->config[n];

                QList<int> usableInterfaces;

                for (int m = 0; m < usbConfig.bNumInterfaces; ++m) {

                    for (int o = 0; o < usbConfig.interface[m].num_altsetting; ++o) {

                        struct usb_interface_descriptor &descriptor = usbConfig.interface[m].altsetting[o];

                        if (descriptor.bInterfaceClass != 2 // "Communication"

                                || descriptor.bInterfaceSubClass != 2 // Abstract (modem)

                                || descriptor.bInterfaceProtocol != 255) // Vendor Specific

                            continue;

                        unsigned char *buf = descriptor.extra;

                        unsigned int size = descriptor.extralen;

                        while (size >= 2 * sizeof(u_int8_t)) {

                            // for Communication devices there is a slave interface for the actual

                            // data transmission.

                            // the extra info stores that as a index for the interface

                            if (buf[0] >= 5 && buf[1] == 36 && buf[2] == 6) { // CDC Union

                                for (int i = 4; i < buf[0]; i++)

                                    usableInterfaces.append((int) buf[i]);

                            }

                            size -= buf[0];

                            buf += buf[0];

                        }

                    }

                }

                // second loop to find the actual data interface.

                foreach (int i, usableInterfaces) {

                    for (int m = 0; m < usbConfig.bNumInterfaces; ++m) {

                        for (int o = 0; o < usbConfig.interface[m].num_altsetting; ++o) {

                            struct usb_interface_descriptor &descriptor = usbConfig.interface[m].altsetting[o];

                            if (descriptor.bInterfaceNumber != i)

                                continue;

                            if (descriptor.bInterfaceClass == 10) { // "CDC Data"

                                // qDebug() << "      found the data port"

                                //     << "bus:" << bus->dirname

                                //     << "device" << device->filename

                                //     << "interface" << descriptor.bInterfaceNumber;

                                eligableInterfaces << QString("if%1").arg(QString::number(i), 2, QChar('0')); // fix!

                            }

                        }

                    }

                }

            }

        }

    }

    foreach (const QFileInfo &info, dir.entryInfoList()) {

            bool usable = eligableInterfaces.isEmpty();

            foreach (const QString &iface, eligableInterfaces) {

                if (info.fileName().contains(iface)) {

                    usable = true;

                    break;

                }

            }

            if (!usable)

                continue;