Qt之QNetworkInterface

简介

用于表示网络接口（即网卡）信息

常用接口

static QList<QNetworkInterface> allInterfaces();
static QList<QHostAddress> allAddresses();
QList<QNetworkAddressEntry> addressEntries() const;

接口类型

用枚举InterfaceType表示

enum InterfaceType {
        Loopback = 1,
        Virtual,
        Ethernet,
        Slip,
        CanBus,
        Ppp,
        Fddi,
        Wifi,
        Ieee80211 = Wifi,   // alias
        Phonet,
        Ieee802154,
        SixLoWPAN,  // 6LoWPAN, but we can't start with a digit
        Ieee80216,
        Ieee1394,

        Unknown = 0
    };

接口状态

用枚举InterfaceFlag表示

enum InterfaceFlag {
        IsUp = 0x1,
        IsRunning = 0x2,
        CanBroadcast = 0x4,
        IsLoopBack = 0x8,
        IsPointToPoint = 0x10,
        CanMulticast = 0x20
    };

结构

QNetworkAddressEntry ：用来表示网络地址实体，即包含地址,广播地址以及掩码
QHostAddress：包含地址以及协议
QHostAddressPrivate成员包含：

QString scopeId;

union {
    Q_IPV6ADDR a6; // IPv6 address
    struct { quint64 c[2]; } a6_64;
    struct { quint32 c[4]; } a6_32;
};
quint32 a;    // IPv4 address
qint8 protocol;

QNetworkInterfaceManager

网络接口管理器，获取电脑上所有可用的网络接口
定义有全局静态变量

Q_GLOBAL_STATIC(QNetworkInterfaceManager, manager)

其结构为

allInterfaces：获取所有的网络接口，先通过scan得到所有网络接口,winrt,win,unix不同平整对scan有不同实现，然后调用 postProcess作后处理

QList<QSharedDataPointer<QNetworkInterfacePrivate> > QNetworkInterfaceManager::allInterfaces()
{
    const QList<QNetworkInterfacePrivate *> list = postProcess(scan());
    QList<QSharedDataPointer<QNetworkInterfacePrivate> > result;
    result.reserve(list.size());

    for (QNetworkInterfacePrivate *ptr : list) {
        if ((ptr->flags & QNetworkInterface::IsUp) == 0) {
            // if the network interface isn't UP, the addresses are ineligible for DNS
            for (auto &addr : ptr->addressEntries)
                addr.setDnsEligibility(QNetworkAddressEntry::DnsIneligible);
        }

        result << QSharedDataPointer<QNetworkInterfacePrivate>(ptr);
    }

    return result;
}

static QList<QNetworkInterfacePrivate *> postProcess(QList<QNetworkInterfacePrivate *> list)
{
    // Some platforms report a netmask but don't report a broadcast address
    // Go through all available addresses and calculate the broadcast address
    // from the IP and the netmask
    //
    // This is an IPv4-only thing -- IPv6 has no concept of broadcasts
    // The math is:
    //    broadcast = IP | ~netmask

    for (QNetworkInterfacePrivate *interface : list) {
        for (QNetworkAddressEntry &address : interface->addressEntries) {
            if (address.ip().protocol() != QAbstractSocket::IPv4Protocol)
                continue;

            if (!address.netmask().isNull() && address.broadcast().isNull()) {
                QHostAddress bcast = address.ip();
                bcast = QHostAddress(bcast.toIPv4Address() | ~address.netmask().toIPv4Address());
                address.setBroadcast(bcast);
            }
        }
    }

    return list;
}