Always assume IPv6 support

It's 2011 baby! And until Qt5 is released probably 2012 :-)

Change-Id: I397aabf25e93c8afb5f562636710985cf0c7acfa
Reviewed-on: http://codereview.qt.nokia.com/1008
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>
Reviewed-by: Martin Petersson <Martin.Petersson@nokia.com>
Reviewed-by: Markus Goetz

8 files changed, 13 insertions, 131 deletions

diff --git a/src/network/kernel/qhostaddress.cpp b/src/network/kernel/qhostaddress.cpp
index bff351c34f..24048113ac 100644
--- a/src/network/kernel/qhostaddress.cpp
+++ b/src/network/kernel/qhostaddress.cpp
@@ -65,7 +65,6 @@ QT_BEGIN_NAMESPACE
     } 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.
@@ -90,12 +89,6 @@ typedef struct {
     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
@@ -545,10 +538,8 @@ QHostAddress::QHostAddress(const struct sockaddr *sockaddr)
 {
     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
 }
 
 /*!
@@ -700,10 +691,8 @@ 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
 }
 
 /*!
diff --git a/src/network/kernel/qhostinfo_unix.cpp b/src/network/kernel/qhostinfo_unix.cpp
index 0a56bc309a..37444ae2d9 100644
--- a/src/network/kernel/qhostinfo_unix.cpp
+++ b/src/network/kernel/qhostinfo_unix.cpp
@@ -149,9 +149,7 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
 // Reverse lookups using getnameinfo are broken on darwin, use gethostbyaddr instead.
 #if !defined (QT_NO_GETADDRINFO) && !defined (Q_OS_DARWIN)
         sockaddr_in sa4;
-#ifndef QT_NO_IPV6
         sockaddr_in6 sa6;
-#endif
         sockaddr *sa = 0;
         QT_SOCKLEN_T saSize = 0;
         if (address.protocol() == QAbstractSocket::IPv4Protocol) {
@@ -161,7 +159,6 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
             sa4.sin_family = AF_INET;
             sa4.sin_addr.s_addr = htonl(address.toIPv4Address());
         }
-#ifndef QT_NO_IPV6
         else {
             sa = (sockaddr *)&sa6;
             saSize = sizeof(sa6);
@@ -169,7 +166,6 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
             sa6.sin6_family = AF_INET6;
             memcpy(sa6.sin6_addr.s6_addr, address.toIPv6Address().c, sizeof(sa6.sin6_addr.s6_addr));
         }
-#endif
 
         char hbuf[NI_MAXHOST];
         if (sa && getnameinfo(sa, saSize, hbuf, sizeof(hbuf), 0, 0, 0) == 0)
@@ -231,7 +227,6 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
                 if (!addresses.contains(addr))
                     addresses.append(addr);
             }
-#ifndef QT_NO_IPV6
             else if (node->ai_family == AF_INET6) {
                 QHostAddress addr;
                 sockaddr_in6 *sa6 = (sockaddr_in6 *) node->ai_addr;
@@ -241,7 +236,6 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
                 if (!addresses.contains(addr))
                     addresses.append(addr);
             }
-#endif
             node = node->ai_next;
         }
         if (addresses.isEmpty() && node == 0) {
diff --git a/src/network/kernel/qnetworkinterface_unix.cpp b/src/network/kernel/qnetworkinterface_unix.cpp
index 0ce21f905f..528e195ef6 100644
--- a/src/network/kernel/qnetworkinterface_unix.cpp
+++ b/src/network/kernel/qnetworkinterface_unix.cpp
@@ -80,10 +80,9 @@ static QHostAddress addressFromSockaddr(sockaddr *sa)
 
     if (sa->sa_family == AF_INET)
         address.setAddress(htonl(((sockaddr_in *)sa)->sin_addr.s_addr));
-#ifndef QT_NO_IPV6
     else if (sa->sa_family == AF_INET6)
         address.setAddress(((sockaddr_in6 *)sa)->sin6_addr.s6_addr);
-#endif
+
     return address;
 
 }
diff --git a/src/network/socket/qabstractsocket.cpp b/src/network/socket/qabstractsocket.cpp
index 9afb21155b..5bad8ec1df 100644
--- a/src/network/socket/qabstractsocket.cpp
+++ b/src/network/socket/qabstractsocket.cpp
@@ -1003,17 +1003,6 @@ void QAbstractSocketPrivate::_q_connectToNextAddress()
                host.toString().toLatin1().constData(), port, addresses.count());
 #endif
 
-#if defined(QT_NO_IPV6)
-        if (host.protocol() == QAbstractSocket::IPv6Protocol) {
-            // If we have no IPv6 support, then we will not be able to
-            // connect. So we just pretend we didn't see this address.
-#if defined(QABSTRACTSOCKET_DEBUG)
-            qDebug("QAbstractSocketPrivate::_q_connectToNextAddress(), skipping IPv6 entry");
-#endif
-            continue;
-        }
-#endif
-
         if (!initSocketLayer(host.protocol())) {
             // hope that the next address is better
 #if defined(QABSTRACTSOCKET_DEBUG)
diff --git a/src/network/socket/qnativesocketengine.cpp b/src/network/socket/qnativesocketengine.cpp
index 875852265e..2dc6a40d99 100644
--- a/src/network/socket/qnativesocketengine.cpp
+++ b/src/network/socket/qnativesocketengine.cpp
@@ -203,6 +203,7 @@ void QNativeSocketEnginePrivate::setError(QAbstractSocket::SocketError error, Er
     case BroadcastingInitFailedErrorString:
         socketErrorString = QNativeSocketEngine::tr("Unable to initialize broadcast socket");
         break;
+    // should not happen anymore
     case NoIpV6ErrorString:
         socketErrorString = QNativeSocketEngine::tr("Attempt to use IPv6 socket on a platform with no IPv6 support");
         break;
@@ -345,14 +346,6 @@ bool QNativeSocketEngine::initialize(QAbstractSocket::SocketType socketType, QAb
     if (isValid())
         close();
 
-#if defined(QT_NO_IPV6)
-    if (protocol == QAbstractSocket::IPv6Protocol) {
-        d->setError(QAbstractSocket::UnsupportedSocketOperationError,
-                    QNativeSocketEnginePrivate::NoIpV6ErrorString);
-        return false;
-    }
-#endif
-
     // Create the socket
     if (!d->createNewSocket(socketType, protocol)) {
 #if defined (QNATIVESOCKETENGINE_DEBUG)
@@ -511,13 +504,6 @@ bool QNativeSocketEngine::connectToHost(const QHostAddress &address, quint16 por
     Q_D(QNativeSocketEngine);
     Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::connectToHost(), false);
 
-#if defined (QT_NO_IPV6)
-    if (address.protocol() == QAbstractSocket::IPv6Protocol) {
-        d->setError(QAbstractSocket::UnsupportedSocketOperationError,
-                    QNativeSocketEnginePrivate::NoIpV6ErrorString);
-        return false;
-    }
-#endif
     if (!d->checkProxy(address))
         return false;
 
@@ -581,13 +567,6 @@ bool QNativeSocketEngine::bind(const QHostAddress &address, quint16 port)
     Q_D(QNativeSocketEngine);
     Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::bind(), false);
 
-#if defined (QT_NO_IPV6)
-    if (address.protocol() == QAbstractSocket::IPv6Protocol) {
-        d->setError(QAbstractSocket::UnsupportedSocketOperationError,
-                    QNativeSocketEnginePrivate::NoIpV6ErrorString);
-        return false;
-    }
-#endif
     if (!d->checkProxy(address))
         return false;
 
diff --git a/src/network/socket/qnativesocketengine_unix.cpp b/src/network/socket/qnativesocketengine_unix.cpp
index 26053981ce..246b5ede9b 100644
--- a/src/network/socket/qnativesocketengine_unix.cpp
+++ b/src/network/socket/qnativesocketengine_unix.cpp
@@ -124,7 +124,6 @@ static void qt_ignore_sigpipe()
 */
 static inline void qt_socket_getPortAndAddress(const qt_sockaddr *s, quint16 *port, QHostAddress *addr)
 {
-#if !defined(QT_NO_IPV6)
     if (s->a.sa_family == AF_INET6) {
         Q_IPV6ADDR tmp;
         memcpy(&tmp, &s->a6.sin6_addr, sizeof(tmp));
@@ -144,7 +143,7 @@ static inline void qt_socket_getPortAndAddress(const qt_sockaddr *s, quint16 *po
             *port = ntohs(s->a6.sin6_port);
         return;
     }
-#endif
+
     if (port)
         *port = ntohs(s->a4.sin_port);
     if (addr) {
@@ -162,12 +161,7 @@ static inline void qt_socket_getPortAndAddress(const qt_sockaddr *s, quint16 *po
 bool QNativeSocketEnginePrivate::createNewSocket(QAbstractSocket::SocketType socketType,
                                          QAbstractSocket::NetworkLayerProtocol socketProtocol)
 {
-#ifndef QT_NO_IPV6
     int protocol = (socketProtocol == QAbstractSocket::IPv6Protocol || socketProtocol == QAbstractSocket::AnyIPProtocol) ? AF_INET6 : AF_INET;
-#else
-    Q_UNUSED(socketProtocol);
-    int protocol = AF_INET;
-#endif
     int type = (socketType == QAbstractSocket::UdpSocket) ? SOCK_DGRAM : SOCK_STREAM;
 
 	int socket = qt_safe_socket(protocol, type, 0);
@@ -238,24 +232,20 @@ int QNativeSocketEnginePrivate::option(QNativeSocketEngine::SocketOption opt) co
         n = SO_KEEPALIVE;
         break;
     case QNativeSocketEngine::MulticastTtlOption:
-#ifndef QT_NO_IPV6
         if (socketProtocol == QAbstractSocket::IPv6Protocol) {
             level = IPPROTO_IPV6;
             n = IPV6_MULTICAST_HOPS;
         } else
-#endif
         {
             level = IPPROTO_IP;
             n = IP_MULTICAST_TTL;
         }
         break;
     case QNativeSocketEngine::MulticastLoopbackOption:
-#ifndef QT_NO_IPV6
         if (socketProtocol == QAbstractSocket::IPv6Protocol) {
             level = IPPROTO_IPV6;
             n = IPV6_MULTICAST_LOOP;
         } else
-#endif
         {
             level = IPPROTO_IP;
             n = IP_MULTICAST_LOOP;
@@ -343,24 +333,20 @@ bool QNativeSocketEnginePrivate::setOption(QNativeSocketEngine::SocketOption opt
         n = SO_KEEPALIVE;
         break;
     case QNativeSocketEngine::MulticastTtlOption:
-#ifndef QT_NO_IPV6
         if (socketProtocol == QAbstractSocket::IPv6Protocol) {
             level = IPPROTO_IPV6;
             n = IPV6_MULTICAST_HOPS;
         } else
-#endif
         {
             level = IPPROTO_IP;
             n = IP_MULTICAST_TTL;
         }
         break;
     case QNativeSocketEngine::MulticastLoopbackOption:
-#ifndef QT_NO_IPV6
         if (socketProtocol == QAbstractSocket::IPv6Protocol) {
             level = IPPROTO_IPV6;
             n = IPV6_MULTICAST_LOOP;
         } else
-#endif
         {
             level = IPPROTO_IP;
             n = IP_MULTICAST_LOOP;
@@ -381,7 +367,6 @@ bool QNativeSocketEnginePrivate::nativeConnect(const QHostAddress &addr, quint16
     struct sockaddr *sockAddrPtr = 0;
     QT_SOCKLEN_T sockAddrSize = 0;
 
-#if !defined(QT_NO_IPV6)
     struct sockaddr_in6 sockAddrIPv6;
 
     if (addr.protocol() == QAbstractSocket::IPv6Protocol) {
@@ -402,10 +387,6 @@ bool QNativeSocketEnginePrivate::nativeConnect(const QHostAddress &addr, quint16
         sockAddrSize = sizeof(sockAddrIPv6);
         sockAddrPtr = (struct sockaddr *) &sockAddrIPv6;
     } else
-#if 0
-    {}
-#endif
-#endif
     if (addr.protocol() == QAbstractSocket::IPv4Protocol) {
         memset(&sockAddrIPv4, 0, sizeof(sockAddrIPv4));
         sockAddrIPv4.sin_family = AF_INET;
@@ -492,7 +473,7 @@ bool QNativeSocketEnginePrivate::nativeBind(const QHostAddress &address, quint16
     struct sockaddr *sockAddrPtr = 0;
     QT_SOCKLEN_T sockAddrSize = 0;
 
-#if !defined(QT_NO_IPV6)
+
     struct sockaddr_in6 sockAddrIPv6;
 
     if (address.protocol() == QAbstractSocket::IPv6Protocol || address.protocol() == QAbstractSocket::AnyIPProtocol) {
@@ -516,7 +497,6 @@ bool QNativeSocketEnginePrivate::nativeBind(const QHostAddress &address, quint16
         sockAddrSize = sizeof(sockAddrIPv6);
         sockAddrPtr = (struct sockaddr *) &sockAddrIPv6;
     } else
-#endif
         if (address.protocol() == QAbstractSocket::IPv4Protocol) {
             memset(&sockAddrIPv4, 0, sizeof(sockAddrIPv4));
             sockAddrIPv4.sin_family = AF_INET;
@@ -612,7 +592,6 @@ static bool multicastMembershipHelper(QNativeSocketEnginePrivate *d,
     int sockArgSize;
 
     ip_mreq mreq4;
-#ifndef QT_NO_IPV6
     ipv6_mreq mreq6;
 
     if (groupAddress.protocol() == QAbstractSocket::IPv6Protocol) {
@@ -625,7 +604,6 @@ static bool multicastMembershipHelper(QNativeSocketEnginePrivate *d,
         memcpy(&mreq6.ipv6mr_multiaddr, &ip6, sizeof(ip6));
         mreq6.ipv6mr_interface = interface.index();
     } else
-#endif
     if (groupAddress.protocol() == QAbstractSocket::IPv4Protocol) {
         level = IPPROTO_IP;
         sockOpt = how4;
@@ -679,11 +657,7 @@ bool QNativeSocketEnginePrivate::nativeJoinMulticastGroup(const QHostAddress &gr
                                                           const QNetworkInterface &interface)
 {
     return multicastMembershipHelper(this,
-#ifndef QT_NO_IPV6
                                      IPV6_JOIN_GROUP,
-#else
-                                     0,
-#endif
                                      IP_ADD_MEMBERSHIP,
                                      groupAddress,
                                      interface);
@@ -693,11 +667,7 @@ bool QNativeSocketEnginePrivate::nativeLeaveMulticastGroup(const QHostAddress &g
                                                            const QNetworkInterface &interface)
 {
     return multicastMembershipHelper(this,
-#ifndef QT_NO_IPV6
                                      IPV6_LEAVE_GROUP,
-#else
-                                     0,
-#endif
                                      IP_DROP_MEMBERSHIP,
                                      groupAddress,
                                      interface);
@@ -705,7 +675,6 @@ bool QNativeSocketEnginePrivate::nativeLeaveMulticastGroup(const QHostAddress &g
 
 QNetworkInterface QNativeSocketEnginePrivate::nativeMulticastInterface() const
 {
-#ifndef QT_NO_IPV6
     if (socketProtocol == QAbstractSocket::IPv6Protocol) {
         uint v;
         QT_SOCKOPTLEN_T sizeofv = sizeof(v);
@@ -713,7 +682,6 @@ QNetworkInterface QNativeSocketEnginePrivate::nativeMulticastInterface() const
             return QNetworkInterface();
         return QNetworkInterface::interfaceFromIndex(v);
     }
-#endif
 
     struct in_addr v = { 0 };
     QT_SOCKOPTLEN_T sizeofv = sizeof(v);
@@ -737,12 +705,10 @@ QNetworkInterface QNativeSocketEnginePrivate::nativeMulticastInterface() const
 
 bool QNativeSocketEnginePrivate::nativeSetMulticastInterface(const QNetworkInterface &iface)
 {
-#ifndef QT_NO_IPV6
     if (socketProtocol == QAbstractSocket::IPv6Protocol) {
         uint v = iface.index();
         return (::setsockopt(socketDescriptor, IPPROTO_IPV6, IPV6_MULTICAST_IF, &v, sizeof(v)) != -1);
     }
-#endif
 
     struct in_addr v;
     if (iface.isValid()) {
@@ -871,7 +837,6 @@ qint64 QNativeSocketEnginePrivate::nativeSendDatagram(const char *data, qint64 l
     struct sockaddr *sockAddrPtr = 0;
     QT_SOCKLEN_T sockAddrSize = 0;
 
-#if !defined(QT_NO_IPV6)
     struct sockaddr_in6 sockAddrIPv6;
     if (host.protocol() == QAbstractSocket::IPv6Protocol
         || socketProtocol == QAbstractSocket::IPv6Protocol) {
@@ -884,7 +849,7 @@ qint64 QNativeSocketEnginePrivate::nativeSendDatagram(const char *data, qint64 l
     sockAddrSize = sizeof(sockAddrIPv6);
     sockAddrPtr = (struct sockaddr *)&sockAddrIPv6;
     } else
-#endif
+
     if (host.protocol() == QAbstractSocket::IPv4Protocol) {
     memset(&sockAddrIPv4, 0, sizeof(sockAddrIPv4));
     sockAddrIPv4.sin_family = AF_INET;
@@ -941,11 +906,9 @@ bool QNativeSocketEnginePrivate::fetchConnectionParameters()
         case AF_INET:
             socketProtocol = QAbstractSocket::IPv4Protocol;
             break;
-#if !defined (QT_NO_IPV6)
         case AF_INET6:
             socketProtocol = QAbstractSocket::IPv6Protocol;
             break;
-#endif
         default:
             socketProtocol = QAbstractSocket::UnknownNetworkLayerProtocol;
             break;
diff --git a/src/network/socket/qnativesocketengine_win.cpp b/src/network/socket/qnativesocketengine_win.cpp
index ba62bd6da2..67a9a2131a 100644
--- a/src/network/socket/qnativesocketengine_win.cpp
+++ b/src/network/socket/qnativesocketengine_win.cpp
@@ -165,7 +165,6 @@ static QByteArray qt_prettyDebug(const char *data, int len, int maxLength)
 */
 static inline void qt_socket_getPortAndAddress(SOCKET socketDescriptor, const qt_sockaddr *sa, quint16 *port, QHostAddress *address)
 {
-#if !defined (QT_NO_IPV6)
     if (sa->a.sa_family == AF_INET6) {
         const qt_sockaddr_in6 *sa6 = &sa->a6;
         Q_IPV6ADDR tmp;
@@ -178,7 +177,7 @@ static inline void qt_socket_getPortAndAddress(SOCKET socketDescriptor, const qt
         if (port)
 	    WSANtohs(socketDescriptor, sa6->sin6_port, port);
     } else
-#endif
+
     if (sa->a.sa_family == AF_INET) {
         const sockaddr_in *sa4 = &sa->a4;
         unsigned long addr;
@@ -200,7 +199,7 @@ static inline void qt_socket_getPortAndAddress(SOCKET socketDescriptor, const qt
 void QNativeSocketEnginePrivate::setPortAndAddress(sockaddr_in * sockAddrIPv4, qt_sockaddr_in6 * sockAddrIPv6,
                                                quint16 port, const QHostAddress & address, sockaddr ** sockAddrPtr, QT_SOCKLEN_T *sockAddrSize)
 {
-#if !defined(QT_NO_IPV6)
+
     if (address.protocol() == QAbstractSocket::IPv6Protocol
         || address.protocol() == QAbstractSocket::AnyIPProtocol
         || socketProtocol == QAbstractSocket::IPv6Protocol) {
@@ -213,7 +212,7 @@ void QNativeSocketEnginePrivate::setPortAndAddress(sockaddr_in * sockAddrIPv4, q
         *sockAddrSize = sizeof(qt_sockaddr_in6);
         *sockAddrPtr = (struct sockaddr *) sockAddrIPv6;
     } else
-#endif
+
     if (address.protocol() == QAbstractSocket::IPv4Protocol
         || address.protocol() == QAbstractSocket::UnknownNetworkLayerProtocol) {
         memset(sockAddrIPv4, 0, sizeof(sockaddr_in));
@@ -403,24 +402,21 @@ int QNativeSocketEnginePrivate::option(QNativeSocketEngine::SocketOption opt) co
         n = SO_KEEPALIVE;
         break;
     case QNativeSocketEngine::MulticastTtlOption:
-#ifndef QT_NO_IPV6
+
         if (socketProtocol == QAbstractSocket::IPv6Protocol) {
             level = IPPROTO_IPV6;
             n = IPV6_MULTICAST_HOPS;
         } else
-#endif
         {
             level = IPPROTO_IP;
             n = IP_MULTICAST_TTL;
         }
         break;
     case QNativeSocketEngine::MulticastLoopbackOption:
-#ifndef QT_NO_IPV6
         if (socketProtocol == QAbstractSocket::IPv6Protocol) {
             level = IPPROTO_IPV6;
             n = IPV6_MULTICAST_LOOP;
         } else
-#endif
         {
             level = IPPROTO_IP;
             n = IP_MULTICAST_LOOP;
@@ -487,24 +483,20 @@ bool QNativeSocketEnginePrivate::setOption(QNativeSocketEngine::SocketOption opt
         n = SO_KEEPALIVE;
         break;
     case QNativeSocketEngine::MulticastTtlOption:
-#ifndef QT_NO_IPV6
         if (socketProtocol == QAbstractSocket::IPv6Protocol) {
             level = IPPROTO_IPV6;
             n = IPV6_MULTICAST_HOPS;
         } else
-#endif
         {
             level = IPPROTO_IP;
             n = IP_MULTICAST_TTL;
         }
         break;
     case QNativeSocketEngine::MulticastLoopbackOption:
-#ifndef QT_NO_IPV6
         if (socketProtocol == QAbstractSocket::IPv6Protocol) {
             level = IPPROTO_IPV6;
             n = IPV6_MULTICAST_LOOP;
         } else
-#endif
         {
             level = IPPROTO_IP;
             n = IP_MULTICAST_LOOP;
@@ -545,11 +537,9 @@ bool QNativeSocketEnginePrivate::fetchConnectionParameters()
         case AF_INET:
             socketProtocol = QAbstractSocket::IPv4Protocol;
             break;
-#if !defined (QT_NO_IPV6)
         case AF_INET6:
             socketProtocol = QAbstractSocket::IPv6Protocol;
             break;
-#endif
         default:
             socketProtocol = QAbstractSocket::UnknownNetworkLayerProtocol;
             break;
@@ -714,7 +704,7 @@ bool QNativeSocketEnginePrivate::nativeBind(const QHostAddress &a, quint16 port)
             // binding to a multicast address
             address = QHostAddress(QHostAddress::AnyIPv6);
         }
-#if !defined (QT_NO_IPV6) && defined (IPV6_V6ONLY)
+#if defined (IPV6_V6ONLY)
         //This is default in current windows versions, it may change in future so set it explicitly
         if (QSysInfo::windowsVersion() >= QSysInfo::WV_6_0) {
             ipv6only = 1;
@@ -729,7 +719,7 @@ bool QNativeSocketEnginePrivate::nativeBind(const QHostAddress &a, quint16 port)
         }
         break;
     case QAbstractSocket::AnyIPProtocol:
-#if !defined (QT_NO_IPV6) && defined (IPV6_V6ONLY)
+#if defined (IPV6_V6ONLY)
         if (QSysInfo::windowsVersion() >= QSysInfo::WV_6_0)
             ipv6only = ::setsockopt(socketDescriptor, IPPROTO_IPV6, IPV6_V6ONLY, (char*)&ipv6only, sizeof(ipv6only) );
         else
@@ -849,7 +839,6 @@ static bool multicastMembershipHelper(QNativeSocketEnginePrivate *d,
     int sockArgSize;
 
     struct ip_mreq mreq4;
-#ifndef QT_NO_IPV6
     struct ipv6_mreq mreq6;
 
     if (groupAddress.protocol() == QAbstractSocket::IPv6Protocol) {
@@ -862,7 +851,7 @@ static bool multicastMembershipHelper(QNativeSocketEnginePrivate *d,
         memcpy(&mreq6.ipv6mr_multiaddr, &ip6, sizeof(ip6));
         mreq6.ipv6mr_interface = iface.index();
     } else
-#endif
+
     if (groupAddress.protocol() == QAbstractSocket::IPv4Protocol) {
         level = IPPROTO_IP;
         sockOpt = how4;
@@ -904,11 +893,7 @@ bool QNativeSocketEnginePrivate::nativeJoinMulticastGroup(const QHostAddress &gr
                                                           const QNetworkInterface &iface)
 {
     return multicastMembershipHelper(this,
-#ifndef QT_NO_IPV6
                                      IPV6_JOIN_GROUP,
-#else
-                                     0,
-#endif
                                      IP_ADD_MEMBERSHIP,
                                      groupAddress,
                                      iface);
@@ -918,11 +903,7 @@ bool QNativeSocketEnginePrivate::nativeLeaveMulticastGroup(const QHostAddress &g
                                                            const QNetworkInterface &iface)
 {
     return multicastMembershipHelper(this,
-#ifndef QT_NO_IPV6
                                      IPV6_LEAVE_GROUP,
-#else
-                                     0,
-#endif
                                      IP_DROP_MEMBERSHIP,
                                      groupAddress,
                                      iface);
@@ -930,7 +911,6 @@ bool QNativeSocketEnginePrivate::nativeLeaveMulticastGroup(const QHostAddress &g
 
 QNetworkInterface QNativeSocketEnginePrivate::nativeMulticastInterface() const
 {
-#ifndef QT_NO_IPV6
     if (socketProtocol == QAbstractSocket::IPv6Protocol) {
         uint v;
         QT_SOCKOPTLEN_T sizeofv = sizeof(v);
@@ -938,7 +918,6 @@ QNetworkInterface QNativeSocketEnginePrivate::nativeMulticastInterface() const
             return QNetworkInterface();
         return QNetworkInterface::interfaceFromIndex(v);
     }
-#endif
 
     struct in_addr v;
     v.s_addr = 0;
@@ -965,12 +944,11 @@ QNetworkInterface QNativeSocketEnginePrivate::nativeMulticastInterface() const
 
 bool QNativeSocketEnginePrivate::nativeSetMulticastInterface(const QNetworkInterface &iface)
 {
-#ifndef QT_NO_IPV6
+
     if (socketProtocol == QAbstractSocket::IPv6Protocol) {
         uint v = iface.isValid() ? iface.index() : 0;
         return (::setsockopt(socketDescriptor, IPPROTO_IPV6, IPV6_MULTICAST_IF, (char *) &v, sizeof(v)) != -1);
     }
-#endif
 
     struct in_addr v;
     if (iface.isValid()) {
diff --git a/src/network/socket/qudpsocket.cpp b/src/network/socket/qudpsocket.cpp
index 6bc93dd7f0..009ce92d8e 100644
--- a/src/network/socket/qudpsocket.cpp
+++ b/src/network/socket/qudpsocket.cpp
@@ -192,15 +192,6 @@ bool QUdpSocketPrivate::doEnsureInitialized(const QHostAddress &bindAddress, qui
         proto = address->protocol();
     }
 
-#if defined(QT_NO_IPV6)
-    Q_Q(QUdpSocket);
-    if (proto == QUdpSocket::IPv6Protocol) {
-        socketError = QUdpSocket::UnsupportedSocketOperationError;
-        q->setErrorString(QUdpSocket::tr("This platform does not support IPv6"));
-        return false;
-    }
-#endif
-
     // now check if the socket engine is initialized and to the right type
     if (!socketEngine || !socketEngine->isValid()) {
         resolveProxy(remoteAddress.toString(), bindPort);