source: trunk/src/network/kernel/qhostaddress.cpp

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** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
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#include "qhostaddress.h"
#include "qhostaddress_p.h"
#include "qdebug.h"
#include "qplatformdefs.h"
#include "qstringlist.h"
#include "qendian.h"
#ifndef QT_NO_DATASTREAM
#include <qdatastream.h>
#endif
#if defined(Q_OS_WINCE)
#include <winsock.h>
#endif

#ifdef QT_LINUXBASE
#  include <arpa/inet.h>
#endif

QT_BEGIN_NAMESPACE

#define QT_ENSURE_PARSED(a) \
    do { \
        if (!(a)->d->isParsed) \
            (a)->d->parse(); \
    } while (0)

#ifdef Q_OS_WIN
#    if !defined (QT_NO_IPV6)
// sockaddr_in6 size changed between old and new SDK
// Only the new version is the correct one, so always
// use this structure.
#if defined(Q_OS_WINCE)
#  if !defined(u_char)
#    define u_char unsigned char
#  endif
#  if !defined(u_short)
#    define u_short unsigned short
#  endif
#  if !defined(u_long)
#    define u_long unsigned long
#  endif
#endif
struct qt_in6_addr {
    u_char qt_s6_addr[16];
};
typedef struct {
    short   sin6_family;            /* AF_INET6 */
    u_short sin6_port;              /* Transport level port number */
    u_long  sin6_flowinfo;          /* IPv6 flow information */
    struct  qt_in6_addr sin6_addr;  /* IPv6 address */
    u_long  sin6_scope_id;          /* set of interfaces for a scope */
} qt_sockaddr_in6;
#    else
typedef void * qt_sockaddr_in6 ;
#    endif
#    ifndef AF_INET6
#        define AF_INET6        23  /* Internetwork Version 6 */
#    endif
#else
#define qt_sockaddr_in6 sockaddr_in6
#define qt_s6_addr s6_addr
#endif


class QHostAddressPrivate
{
public:
    QHostAddressPrivate();

    void setAddress(quint32 a_ = 0);
    void setAddress(const quint8 *a_);
    void setAddress(const Q_IPV6ADDR &a_);

    bool parse();
    void clear();

    quint32 a;    // IPv4 address
    Q_IPV6ADDR a6; // IPv6 address
    QAbstractSocket::NetworkLayerProtocol protocol;

    QString ipString;
    bool isParsed;
    QString scopeId;

    friend class QHostAddress;
};

QHostAddressPrivate::QHostAddressPrivate()
    : a(0), protocol(QAbstractSocket::UnknownNetworkLayerProtocol), isParsed(true)
{
    memset(&a6, 0, sizeof(a6));
}

void QHostAddressPrivate::setAddress(quint32 a_)
{
    a = a_;
    protocol = QAbstractSocket::IPv4Protocol;
    isParsed = true;
}

void QHostAddressPrivate::setAddress(const quint8 *a_)
{
    for (int i = 0; i < 16; i++)
        a6[i] = a_[i];
    protocol = QAbstractSocket::IPv6Protocol;
    isParsed = true;
}

void QHostAddressPrivate::setAddress(const Q_IPV6ADDR &a_)
{
    a6 = a_;
    a = 0;
    protocol = QAbstractSocket::IPv6Protocol;
    isParsed = true;
}

static bool parseIp4(const QString& address, quint32 *addr)
{
    QStringList ipv4 = address.split(QLatin1String("."));
    if (ipv4.count() != 4)
        return false;

    quint32 ipv4Address = 0;
    for (int i = 0; i < 4; ++i) {
        bool ok = false;
        uint byteValue = ipv4.at(i).toUInt(&ok);
        if (!ok || byteValue > 255)
            return false;

        ipv4Address <<= 8;
        ipv4Address += byteValue;
    }

    *addr = ipv4Address;
    return true;
}

static bool parseIp6(const QString &address, quint8 *addr, QString *scopeId)
{
    QString tmp = address;
    int scopeIdPos = tmp.lastIndexOf(QLatin1Char('%'));
    if (scopeIdPos != -1) {
        *scopeId = tmp.mid(scopeIdPos + 1);
        tmp.chop(tmp.size() - scopeIdPos);
    } else {
        scopeId->clear();
    }

    QStringList ipv6 = tmp.split(QLatin1String(":"));
    int count = ipv6.count();
    if (count < 3 || count > 8)
        return false;

    int colonColon = tmp.count(QLatin1String("::"));
    if(count == 8 && colonColon > 1)
        return false;

    // address can be compressed with a "::", but that
    // may only appear once (see RFC 1884)
    // the statement below means:
    // if(shortened notation is not used AND
    // ((pure IPv6 notation AND less than 8 parts) OR
    // ((mixed IPv4/6 notation AND less than 7 parts)))
    if(colonColon != 1 && count < (tmp.contains(QLatin1Char('.')) ? 7 : 8))
        return false;

    int mc = 16;
    int fillCount = 9 - count;  // number of 0 words to fill in the middle
    for (int i = count - 1; i >= 0; --i) {
        if (mc <= 0)
            return false;

        if (ipv6.at(i).isEmpty()) {
            if (i == count - 1) {
                // special case: ":" is last character
                if (!ipv6.at(i - 1).isEmpty())
                    return false;
                addr[--mc] = 0;
                addr[--mc] = 0;
            } else if (i == 0) {
                // special case: ":" is first character
                if (!ipv6.at(i + 1).isEmpty())
                    return false;
                addr[--mc] = 0;
                addr[--mc] = 0;
            } else {
                for (int j = 0; j < fillCount; ++j) {
                    if (mc <= 0)
                        return false;
                    addr[--mc] = 0;
                    addr[--mc] = 0;
                }
            }
        } else {
            bool ok = false;
            uint byteValue = ipv6.at(i).toUInt(&ok, 16);
            if (ok && byteValue <= 0xffff) {
                addr[--mc] = byteValue & 0xff;
                addr[--mc] = (byteValue >> 8) & 0xff;
            } else {
                if (i != count - 1)
                    return false;

                // parse the ipv4 part of a mixed type
                quint32 maybeIp4;
                if (!parseIp4(ipv6.at(i), &maybeIp4))
                    return false;

                addr[--mc] = maybeIp4 & 0xff;
                addr[--mc] = (maybeIp4 >> 8) & 0xff;
                addr[--mc] = (maybeIp4 >> 16) & 0xff;
                addr[--mc] = (maybeIp4 >> 24) & 0xff;
                --fillCount;
            }
        }
    }

    return true;
}

bool QHostAddressPrivate::parse()
{
    isParsed = true;
    protocol = QAbstractSocket::UnknownNetworkLayerProtocol;
    QString a = ipString.simplified();

    // All IPv6 addresses contain a ':', and may contain a '.'.
    if (a.contains(QLatin1Char(':'))) {
        quint8 maybeIp6[16];
        if (parseIp6(a, maybeIp6, &scopeId)) {
            setAddress(maybeIp6);
            protocol = QAbstractSocket::IPv6Protocol;
            return true;
        }
    }

    // All IPv4 addresses contain a '.'.
    if (a.contains(QLatin1Char('.'))) {
        quint32 maybeIp4 = 0;
        if (parseIp4(a, &maybeIp4)) {
            setAddress(maybeIp4);
            protocol = QAbstractSocket::IPv4Protocol;
            return true;
        }
    }

    return false;
}

void QHostAddressPrivate::clear()
{
    a = 0;
    protocol = QAbstractSocket::UnknownNetworkLayerProtocol;
    isParsed = true;
    memset(&a6, 0, sizeof(a6));
}


bool QNetmaskAddress::setAddress(const QString &address)
{
    length = -1;
    QHostAddress other;
    return other.setAddress(address) && setAddress(other);
}

bool QNetmaskAddress::setAddress(const QHostAddress &address)
{
    static const quint8 zeroes[16] = { 0 };
    union {
        quint32 v4;
        quint8 v6[16];
    } ip;

    int netmask = 0;
    quint8 *ptr = ip.v6;
    quint8 *end;
    length = -1;

    QHostAddress::operator=(address);

    if (d->protocol == QAbstractSocket::IPv4Protocol) {
        ip.v4 = qToBigEndian(d->a);
        end = ptr + 4;
    } else if (d->protocol == QAbstractSocket::IPv6Protocol) {
        memcpy(ip.v6, d->a6.c, 16);
        end = ptr + 16;
    } else {
        d->clear();
        return false;
    }

    while (ptr < end) {
        switch (*ptr) {
        case 255:
            netmask += 8;
            ++ptr;
            continue;

        default:
            d->clear();
            return false;       // invalid IP-style netmask

            // the rest always falls through
        case 254:
            ++netmask;
        case 252:
            ++netmask;
        case 248:
            ++netmask;
        case 240:
            ++netmask;
        case 224:
            ++netmask;
        case 192:
            ++netmask;
        case 128:
            ++netmask;
        case 0:
            break;
        }
        break;
    }

    // confirm that the rest is only zeroes
    if (ptr < end && memcmp(ptr + 1, zeroes, end - ptr - 1) != 0) {
        d->clear();
        return false;
    }

    length = netmask;
    return true;
}

static void clearBits(quint8 *where, int start, int end)
{
    Q_ASSERT(end == 32 || end == 128);
    if (start == end)
        return;

    // for the byte where 'start' is, clear the lower bits only
    quint8 bytemask = 256 - (1 << (8 - (start & 7)));
    where[start / 8] &= bytemask;

    // for the tail part, clear everything
    memset(where + (start + 7) / 8, 0, end / 8 - (start + 7) / 8);
}

int QNetmaskAddress::prefixLength() const
{
    return length;
}

void QNetmaskAddress::setPrefixLength(QAbstractSocket::NetworkLayerProtocol proto, int newLength)
{
    length = newLength;
    if (length < 0 || length > (proto == QAbstractSocket::IPv4Protocol ? 32 :
                                proto == QAbstractSocket::IPv6Protocol ? 128 : -1)) {
        // invalid information, reject
        d->protocol = QAbstractSocket::UnknownNetworkLayerProtocol;
        length = -1;
        return;
    }

    d->protocol = proto;
    if (d->protocol == QAbstractSocket::IPv4Protocol) {
        if (length == 0) {
            d->a = 0;
        } else if (length == 32) {
            d->a = quint32(0xffffffff);
        } else {
            d->a = quint32(0xffffffff) >> (32 - length) << (32 - length);
        }
    } else {
        memset(d->a6.c, 0xFF, sizeof(d->a6));
        clearBits(d->a6.c, length, 128);
    }
}

/*!
    \class QHostAddress
    \brief The QHostAddress class provides an IP address.
    \ingroup network
    \inmodule QtNetwork

    This class holds an IPv4 or IPv6 address in a platform- and
    protocol-independent manner.

    QHostAddress is normally used with the QTcpSocket, QTcpServer,
    and QUdpSocket to connect to a host or to set up a server.

    A host address is set with setAddress(), and retrieved with
    toIPv4Address(), toIPv6Address(), or toString(). You can check the
    type with protocol().

    \note Please note that QHostAddress does not do DNS lookups.
    QHostInfo is needed for that.

    The class also supports common predefined addresses: \l Null, \l
    LocalHost, \l LocalHostIPv6, \l Broadcast, and \l Any.

    \sa QHostInfo, QTcpSocket, QTcpServer, QUdpSocket
*/

/*! \enum QHostAddress::SpecialAddress

    \value Null The null address object. Equivalent to QHostAddress().
    \value LocalHost The IPv4 localhost address. Equivalent to QHostAddress("127.0.0.1").
    \value LocalHostIPv6 The IPv6 localhost address. Equivalent to QHostAddress("::1").
    \value Broadcast The IPv4 broadcast address. Equivalent to QHostAddress("255.255.255.255").
    \value Any The IPv4 any-address. Equivalent to QHostAddress("0.0.0.0").
    \value AnyIPv6 The IPv6 any-address. Equivalent to QHostAddress("::").
*/

/*!  Constructs a host address object with the IP address 0.0.0.0.

    \sa clear()
*/
QHostAddress::QHostAddress()
    : d(new QHostAddressPrivate)
{
}

/*!
    Constructs a host address object with the IPv4 address \a ip4Addr.
*/
QHostAddress::QHostAddress(quint32 ip4Addr)
    : d(new QHostAddressPrivate)
{
    setAddress(ip4Addr);
}

/*!
    Constructs a host address object with the IPv6 address \a ip6Addr.

    \a ip6Addr must be a 16-byte array in network byte order (big
    endian).
*/
QHostAddress::QHostAddress(quint8 *ip6Addr)
    : d(new QHostAddressPrivate)
{
    setAddress(ip6Addr);
}

/*!
    Constructs a host address object with the IPv6 address \a ip6Addr.
*/
QHostAddress::QHostAddress(const Q_IPV6ADDR &ip6Addr)
    : d(new QHostAddressPrivate)
{
    setAddress(ip6Addr);
}

/*!
    Constructs an IPv4 or IPv6 address based on the string \a address
    (e.g., "127.0.0.1").

    \sa setAddress()
*/
QHostAddress::QHostAddress(const QString &address)
    : d(new QHostAddressPrivate)
{
    d->ipString = address;
    d->isParsed = false;
}

/*!
    \fn QHostAddress::QHostAddress(const sockaddr *sockaddr)

    Constructs an IPv4 or IPv6 address using the address specified by
    the native structure \a sockaddr.

    \sa setAddress()
*/
QHostAddress::QHostAddress(const struct sockaddr *sockaddr)
    : d(new QHostAddressPrivate)
{
    if (sockaddr->sa_family == AF_INET)
        setAddress(htonl(((sockaddr_in *)sockaddr)->sin_addr.s_addr));
#ifndef QT_NO_IPV6
    else if (sockaddr->sa_family == AF_INET6)
        setAddress(((qt_sockaddr_in6 *)sockaddr)->sin6_addr.qt_s6_addr);
#endif
}

/*!
    Constructs a copy of the given \a address.
*/
QHostAddress::QHostAddress(const QHostAddress &address)
    : d(new QHostAddressPrivate(*address.d.data()))
{
}

/*!
    Constructs a QHostAddress object for \a address.
*/
QHostAddress::QHostAddress(SpecialAddress address)
    : d(new QHostAddressPrivate)
{
    switch (address) {
    case Null:
        break;
    case Broadcast:
        setAddress(QLatin1String("255.255.255.255"));
        break;
    case LocalHost:
        setAddress(QLatin1String("127.0.0.1"));
        break;
    case LocalHostIPv6:
        setAddress(QLatin1String("::1"));
        break;
    case Any:
        setAddress(QLatin1String("0.0.0.0"));
        break;
    case AnyIPv6:
        setAddress(QLatin1String("::"));
        break;
    }
}

/*!
    Destroys the host address object.
*/
QHostAddress::~QHostAddress()
{
}

/*!
    Assigns another host \a address to this object, and returns a reference
    to this object.
*/
QHostAddress &QHostAddress::operator=(const QHostAddress &address)
{
    *d.data() = *address.d.data();
    return *this;
}

/*!
    Assigns the host address \a address to this object, and returns a
    reference to this object.

    \sa setAddress()
*/
QHostAddress &QHostAddress::operator=(const QString &address)
{
    setAddress(address);
    return *this;
}

/*!
    \fn bool QHostAddress::operator!=(const QHostAddress &other) const
    \since 4.2

    Returns true if this host address is not the same as the \a other
    address given; otherwise returns false.
*/

/*!
    \fn bool QHostAddress::operator!=(SpecialAddress other) const

    Returns true if this host address is not the same as the \a other
    address given; otherwise returns false.
*/

/*!
    Sets the host address to 0.0.0.0.
*/
void QHostAddress::clear()
{
    d->clear();
}

/*!
    Set the IPv4 address specified by \a ip4Addr.
*/
void QHostAddress::setAddress(quint32 ip4Addr)
{
    d->setAddress(ip4Addr);
}

/*!
    \overload

    Set the IPv6 address specified by \a ip6Addr.

    \a ip6Addr must be an array of 16 bytes in network byte order
    (high-order byte first).
*/
void QHostAddress::setAddress(quint8 *ip6Addr)
{
    d->setAddress(ip6Addr);
}

/*!
    \overload

    Set the IPv6 address specified by \a ip6Addr.
*/
void QHostAddress::setAddress(const Q_IPV6ADDR &ip6Addr)
{
    d->setAddress(ip6Addr);
}

/*!
    \overload

    Sets the IPv4 or IPv6 address specified by the string
    representation specified by \a address (e.g. "127.0.0.1").
    Returns true and sets the address if the address was successfully
    parsed; otherwise returns false.
*/
bool QHostAddress::setAddress(const QString &address)
{
    d->ipString = address;
    return d->parse();
}

/*!
    \fn void QHostAddress::setAddress(const sockaddr *sockaddr)
    \overload

    Sets the IPv4 or IPv6 address specified by the native structure \a
    sockaddr.  Returns true and sets the address if the address was
    successfully parsed; otherwise returns false.
*/
void QHostAddress::setAddress(const struct sockaddr *sockaddr)
{
    clear();
    if (sockaddr->sa_family == AF_INET)
        setAddress(htonl(((sockaddr_in *)sockaddr)->sin_addr.s_addr));
#ifndef QT_NO_IPV6
    else if (sockaddr->sa_family == AF_INET6)
        setAddress(((qt_sockaddr_in6 *)sockaddr)->sin6_addr.qt_s6_addr);
#endif
}

/*!
    Returns the IPv4 address as a number.

    For example, if the address is 127.0.0.1, the returned value is
    2130706433 (i.e. 0x7f000001).

    This value is only valid if the Protocol() is
    \l{QAbstractSocket::}{IPv4Protocol}.

    \sa toString()
*/
quint32 QHostAddress::toIPv4Address() const
{
    QT_ENSURE_PARSED(this);
    return d->a;
}

/*!
    Returns the network layer protocol of the host address.
*/
QAbstractSocket::NetworkLayerProtocol QHostAddress::protocol() const
{
    QT_ENSURE_PARSED(this);
    return d->protocol;
}

/*!
    Returns the IPv6 address as a Q_IPV6ADDR structure. The structure
    consists of 16 unsigned characters.

    \snippet doc/src/snippets/code/src_network_kernel_qhostaddress.cpp 0

    This value is only valid if the protocol() is
    \l{QAbstractSocket::}{IPv6Protocol}.

    \sa toString()
*/
Q_IPV6ADDR QHostAddress::toIPv6Address() const
{
    QT_ENSURE_PARSED(this);
    return d->a6;
}

/*!
    Returns the address as a string.

    For example, if the address is the IPv4 address 127.0.0.1, the
    returned string is "127.0.0.1".

    \sa toIPv4Address()
*/
QString QHostAddress::toString() const
{
    QT_ENSURE_PARSED(this);
    if (d->protocol == QAbstractSocket::IPv4Protocol) {
        quint32 i = toIPv4Address();
        QString s;
        s.sprintf("%d.%d.%d.%d", (i>>24) & 0xff, (i>>16) & 0xff,
                (i >> 8) & 0xff, i & 0xff);
        return s;
    }

    if (d->protocol == QAbstractSocket::IPv6Protocol) {
        quint16 ugle[8];
        for (int i = 0; i < 8; i++) {
            ugle[i] = (quint16(d->a6[2*i]) << 8) | quint16(d->a6[2*i+1]);
        }
        QString s;
        s.sprintf("%X:%X:%X:%X:%X:%X:%X:%X",
                  ugle[0], ugle[1], ugle[2], ugle[3], ugle[4], ugle[5], ugle[6], ugle[7]);
        if (!d->scopeId.isEmpty())
            s.append(QLatin1Char('%') + d->scopeId);
        return s;
    }

    return QString();
}

/*!
    \since 4.1

    Returns the scope ID of an IPv6 address. For IPv4 addresses, or if the
    address does not contain a scope ID, an empty QString is returned.

    The IPv6 scope ID specifies the scope of \e reachability for non-global
    IPv6 addresses, limiting the area in which the address can be used. All
    IPv6 addresses are associated with such a reachability scope. The scope ID
    is used to disambiguate addresses that are not guaranteed to be globally
    unique.

    IPv6 specifies the following four levels of reachability:

    \list

    \o Node-local: Addresses that are only used for communicating with
    services on the same interface (e.g., the loopback interface "::1").

    \o Link-local: Addresses that are local to the network interface
    (\e{link}). There is always one link-local address for each IPv6 interface
    on your host. Link-local addresses ("fe80...") are generated from the MAC
    address of the local network adaptor, and are not guaranteed to be unique.

    \o Site-local: Addresses that are local to the site / private network
    (e.g., the company intranet). Site-local addresses ("fec0...")  are
    usually distributed by the site router, and are not guaranteed to be
    unique outside of the local site.

    \o Global: For globally routable addresses, such as public servers on the
    Internet.

    \endlist

    When using a link-local or site-local address for IPv6 connections, you
    must specify the scope ID. The scope ID for a link-local address is
    usually the same as the interface name (e.g., "eth0", "en1") or number
    (e.g., "1", "2").

    \sa setScopeId()
*/
QString QHostAddress::scopeId() const
{
    QT_ENSURE_PARSED(this);
    return (d->protocol == QAbstractSocket::IPv6Protocol) ? d->scopeId : QString();
}

/*!
    \since 4.1

    Sets the IPv6 scope ID of the address to \a id. If the address
    protocol is not IPv6, this function does nothing.
*/
void QHostAddress::setScopeId(const QString &id)
{
    QT_ENSURE_PARSED(this);
    if (d->protocol == QAbstractSocket::IPv6Protocol)
        d->scopeId = id;
}

/*!
    Returns true if this host address is the same as the \a other address
    given; otherwise returns false.
*/
bool QHostAddress::operator==(const QHostAddress &other) const
{
    QT_ENSURE_PARSED(this);
    QT_ENSURE_PARSED(&other);

    if (d->protocol == QAbstractSocket::IPv4Protocol)
        return other.d->protocol == QAbstractSocket::IPv4Protocol && d->a == other.d->a;
    if (d->protocol == QAbstractSocket::IPv6Protocol) {
        return other.d->protocol == QAbstractSocket::IPv6Protocol
               && memcmp(&d->a6, &other.d->a6, sizeof(Q_IPV6ADDR)) == 0;
    }
    return d->protocol == other.d->protocol;
}

/*!
    Returns true if this host address is the same as the \a other
    address given; otherwise returns false.
*/
bool QHostAddress::operator ==(SpecialAddress other) const
{
    QT_ENSURE_PARSED(this);
    QHostAddress otherAddress(other);
    QT_ENSURE_PARSED(&otherAddress);

    if (d->protocol == QAbstractSocket::IPv4Protocol)
        return otherAddress.d->protocol == QAbstractSocket::IPv4Protocol && d->a == otherAddress.d->a;
    if (d->protocol == QAbstractSocket::IPv6Protocol) {
        return otherAddress.d->protocol == QAbstractSocket::IPv6Protocol
               && memcmp(&d->a6, &otherAddress.d->a6, sizeof(Q_IPV6ADDR)) == 0;
    }
    return int(other) == int(Null);
}

/*!
    Returns true if this host address is null (INADDR_ANY or in6addr_any).
    The default constructor creates a null address, and that address is
    not valid for any host or interface.
*/
bool QHostAddress::isNull() const
{
    QT_ENSURE_PARSED(this);
    return d->protocol == QAbstractSocket::UnknownNetworkLayerProtocol;
}

/*!
    \fn quint32 QHostAddress::ip4Addr() const

    Use toIPv4Address() instead.
*/

/*!
    \fn bool QHostAddress::isIp4Addr() const

    Use protocol() instead.
*/

/*!
    \fn bool QHostAddress::isIPv4Address() const

    Use protocol() instead.
*/

/*!
    \fn bool QHostAddress::isIPv6Address() const

    Use protocol() instead.
*/

/*!
    \since 4.5

    Returns true if this IP is in the subnet described by the network
    prefix \a subnet and netmask \a netmask.

    An IP is considered to belong to a subnet if it is contained
    between the lowest and the highest address in that subnet. In the
    case of IP version 4, the lowest address is the network address,
    while the highest address is the broadcast address.

    The \a subnet argument does not have to be the actual network
    address (the lowest address in the subnet). It can be any valid IP
    belonging to that subnet. In particular, if it is equal to the IP
    address held by this object, this function will always return true
    (provided the netmask is a valid value).

    \sa parseSubnet()
*/
bool QHostAddress::isInSubnet(const QHostAddress &subnet, int netmask) const
{
    QT_ENSURE_PARSED(this);
    if (subnet.protocol() != d->protocol || netmask < 0)
        return false;

    union {
        quint32 ip;
        quint8 data[4];
    } ip4, net4;
    const quint8 *ip;
    const quint8 *net;
    if (d->protocol == QAbstractSocket::IPv4Protocol) {
        if (netmask > 32)
            netmask = 32;
        ip4.ip = qToBigEndian(d->a);
        net4.ip = qToBigEndian(subnet.d->a);
        ip = ip4.data;
        net = net4.data;
    } else if (d->protocol == QAbstractSocket::IPv6Protocol) {
        if (netmask > 128)
            netmask = 128;
        ip = d->a6.c;
        net = subnet.d->a6.c;
    } else {
        return false;
    }

    if (netmask >= 8 && memcmp(ip, net, netmask / 8) != 0)
        return false;
    if ((netmask & 7) == 0)
        return true;

    // compare the last octet now
    quint8 bytemask = 256 - (1 << (8 - (netmask & 7)));
    quint8 ipbyte = ip[netmask / 8];
    quint8 netbyte = net[netmask / 8];
    return (ipbyte & bytemask) == (netbyte & bytemask);
}

/*!
    \since 4.5
    \overload

    Returns true if this IP is in the subnet described by \a
    subnet. The QHostAddress member of \a subnet contains the network
    prefix and the int (second) member contains the netmask (prefix
    length).
*/
bool QHostAddress::isInSubnet(const QPair<QHostAddress, int> &subnet) const
{
    return isInSubnet(subnet.first, subnet.second);
}


/*!
    \since 4.5

    Parses the IP and subnet information contained in \a subnet and
    returns the network prefix for that network and its prefix length.

    The IP address and the netmask must be separated by a slash
    (/).

    This function supports arguments in the form:
    \list
      \o 123.123.123.123/n  where n is any value between 0 and 32
      \o 123.123.123.123/255.255.255.255
      \o <ipv6-address>/n  where n is any value between 0 and 128
    \endlist

    For IP version 4, this function accepts as well missing trailing
    components (i.e., less than 4 octets, like "192.168.1"), followed
    or not by a dot. If the netmask is also missing in that case, it
    is set to the number of octets actually passed (in the example
    above, it would be 24, for 3 octets).

    \sa isInSubnet()
*/
QPair<QHostAddress, int> QHostAddress::parseSubnet(const QString &subnet)
{
    // We support subnets in the form:
    //   ddd.ddd.ddd.ddd/nn
    //   ddd.ddd.ddd/nn
    //   ddd.ddd/nn
    //   ddd/nn
    //   ddd.ddd.ddd.
    //   ddd.ddd.ddd
    //   ddd.ddd.
    //   ddd.ddd
    //   ddd.
    //   ddd
    //   <ipv6-address>/nn
    //
    //  where nn can be an IPv4-style netmask for the IPv4 forms

    const QPair<QHostAddress, int> invalid = qMakePair(QHostAddress(), -1);
    if (subnet.isEmpty())
        return invalid;

    int slash = subnet.indexOf(QLatin1Char('/'));
    QString netStr = subnet;
    if (slash != -1)
        netStr.truncate(slash);

    int netmask = -1;
    bool isIpv6 = netStr.contains(QLatin1Char(':'));

    if (slash != -1) {
        // is the netmask given in IP-form or in bit-count form?
        if (!isIpv6 && subnet.indexOf(QLatin1Char('.'), slash + 1) != -1) {
            // IP-style, convert it to bit-count form
            QNetmaskAddress parser;
            if (!parser.setAddress(subnet.mid(slash + 1)))
                return invalid;
            netmask = parser.prefixLength();
        } else {
            bool ok;
            netmask = subnet.mid(slash + 1).toUInt(&ok);
            if (!ok)
                return invalid;     // failed to parse the subnet
        }
    }

    if (isIpv6) {
        // looks like it's an IPv6 address
        if (netmask > 128)
            return invalid;     // invalid netmask
        if (netmask < 0)
            netmask = 128;

        QHostAddress net;
        if (!net.setAddress(netStr))
            return invalid;     // failed to parse the IP

        clearBits(net.d->a6.c, netmask, 128);
        return qMakePair(net, netmask);
    }

    if (netmask > 32)
        return invalid;         // invalid netmask

    // parse the address manually
    QStringList parts = netStr.split(QLatin1Char('.'));
    if (parts.isEmpty() || parts.count() > 4)
        return invalid;         // invalid IPv4 address

    if (parts.last().isEmpty())
        parts.removeLast();

    quint32 addr = 0;
    for (int i = 0; i < parts.count(); ++i) {
        bool ok;
        uint byteValue = parts.at(i).toUInt(&ok);
        if (!ok || byteValue > 255)
            return invalid;     // invalid IPv4 address

        addr <<= 8;
        addr += byteValue;
    }
    addr <<= 8 * (4 - parts.count());
    if (netmask == -1) {
        netmask = 8 * parts.count();
    } else if (netmask == 0) {
        // special case here
        // x86's instructions "shr" and "shl" do not operate when
        // their argument is 32, so the code below doesn't work as expected
        addr = 0;
    } else if (netmask != 32) {
        // clear remaining bits
        quint32 mask = quint32(0xffffffff) >> (32 - netmask) << (32 - netmask);
        addr &= mask;
    }

    return qMakePair(QHostAddress(addr), netmask);
}

#ifndef QT_NO_DEBUG_STREAM
QDebug operator<<(QDebug d, const QHostAddress &address)
{
    d.maybeSpace() << "QHostAddress(" << address.toString() << ')';
    return d.space();
}
#endif

uint qHash(const QHostAddress &key)
{
    return qHash(key.toString());
}

#ifndef QT_NO_DATASTREAM

/*! \relates QHostAddress

    Writes host address \a address to the stream \a out and returns a reference
    to the stream.

    \sa {Serializing Qt Data Types}
*/
QDataStream &operator<<(QDataStream &out, const QHostAddress &address)
{
    qint8 prot;
    prot = qint8(address.protocol());
    out << prot;
    switch (address.protocol()) {
    case QAbstractSocket::UnknownNetworkLayerProtocol:
        break;
    case QAbstractSocket::IPv4Protocol:
        out << address.toIPv4Address();
        break;
    case QAbstractSocket::IPv6Protocol:
    {
        Q_IPV6ADDR ipv6 = address.toIPv6Address();
        for (int i = 0; i < 16; ++i)
            out << ipv6[i];
        out << address.scopeId();
    }
        break;
    }
    return out;
}

/*! \relates QHostAddress

    Reads a host address into \a address from the stream \a in and returns a
    reference to the stream.

    \sa {Serializing Qt Data Types}
*/
QDataStream &operator>>(QDataStream &in, QHostAddress &address)
{
    qint8 prot;
    in >> prot;
    switch (QAbstractSocket::NetworkLayerProtocol(prot)) {
    case QAbstractSocket::UnknownNetworkLayerProtocol:
        address.clear();
        break;
    case QAbstractSocket::IPv4Protocol:
    {
        quint32 ipv4;
        in >> ipv4;
        address.setAddress(ipv4);
    }
        break;
    case QAbstractSocket::IPv6Protocol:
    {
        Q_IPV6ADDR ipv6;
        for (int i = 0; i < 16; ++i)
            in >> ipv6[i];
        address.setAddress(ipv6);

        QString scope;
        in >> scope;
        address.setScopeId(scope);
    }
        break;
    default:
        address.clear();
        in.setStatus(QDataStream::ReadCorruptData);
    }
    return in;
}

#endif //QT_NO_DATASTREAM

QT_END_NAMESPACE