Add QUdpSocket::setMulticastInterface() and ::multicastInterface()

This API allows the programmer to set/query the outgoing interface for
multicast packets for the socket. Both functions need an initialized
socket to work.

Autotest updated to test setting each interface in the system as the
multicast interface for IPv4 and IPv6 UDP sockets.

11 files changed, 269 insertions, 11 deletions

diff --git a/src/network/socket/qabstractsocketengine_p.h b/src/network/socket/qabstractsocketengine_p.h
index 616fdb2..ec5fbd3 100644
--- a/src/network/socket/qabstractsocketengine_p.h
+++ b/src/network/socket/qabstractsocketengine_p.h
@@ -125,6 +125,8 @@ public:
                                     const QNetworkInterface &iface) = 0;
     virtual bool leaveMulticastGroup(const QHostAddress &groupAddress,
                                      const QNetworkInterface &iface) = 0;
+    virtual QNetworkInterface multicastInterface() const = 0;
+    virtual bool setMulticastInterface(const QNetworkInterface &iface) = 0;
 
     virtual qint64 readDatagram(char *data, qint64 maxlen, QHostAddress *addr = 0,
                                 quint16 *port = 0) = 0;
diff --git a/src/network/socket/qhttpsocketengine.cpp b/src/network/socket/qhttpsocketengine.cpp
index e467df8..cb0e296 100644
--- a/src/network/socket/qhttpsocketengine.cpp
+++ b/src/network/socket/qhttpsocketengine.cpp
@@ -45,6 +45,7 @@
 #include "qurl.h"
 #include "qhttp.h"
 #include "qelapsedtimer.h"
+#include "qnetworkinterface.h"
 
 #if !defined(QT_NO_NETWORKPROXY) && !defined(QT_NO_HTTP)
 #include <qdebug.h>
@@ -255,6 +256,18 @@ bool QHttpSocketEngine::leaveMulticastGroup(const QHostAddress &,
     return false;
 }
 
+QNetworkInterface QHttpSocketEngine::multicastInterface() const
+{
+    return QNetworkInterface();
+}
+
+bool QHttpSocketEngine::setMulticastInterface(const QNetworkInterface &)
+{
+    setError(QAbstractSocket::UnsupportedSocketOperationError,
+             QLatin1String("Operation on socket is not supported"));
+    return false;
+}
+
 qint64 QHttpSocketEngine::readDatagram(char *, qint64, QHostAddress *,
                                        quint16 *)
 {
diff --git a/src/network/socket/qhttpsocketengine_p.h b/src/network/socket/qhttpsocketengine_p.h
index 1a6b4f6..b68b7117 100644
--- a/src/network/socket/qhttpsocketengine_p.h
+++ b/src/network/socket/qhttpsocketengine_p.h
@@ -106,6 +106,8 @@ public:
                             const QNetworkInterface &interface);
     bool leaveMulticastGroup(const QHostAddress &groupAddress,
                              const QNetworkInterface &interface);
+    QNetworkInterface multicastInterface() const;
+    bool setMulticastInterface(const QNetworkInterface &iface);
 
     qint64 readDatagram(char *data, qint64 maxlen, QHostAddress *addr = 0,
         quint16 *port = 0);
diff --git a/src/network/socket/qnativesocketengine.cpp b/src/network/socket/qnativesocketengine.cpp
index 7cb3a1b..df73b9c 100644
--- a/src/network/socket/qnativesocketengine.cpp
+++ b/src/network/socket/qnativesocketengine.cpp
@@ -98,6 +98,7 @@
 
 #include <qabstracteventdispatcher.h>
 #include <qsocketnotifier.h>
+#include <qnetworkinterface.h>
 
 #include "qnativesocketengine_p.h"
 #include <private/qthread_p.h>
@@ -672,6 +673,25 @@ bool QNativeSocketEngine::leaveMulticastGroup(const QHostAddress &groupAddress,
     return d->nativeLeaveMulticastGroup(groupAddress, iface);
 }
 
+/*! \since 4.8 */
+QNetworkInterface QNativeSocketEngine::multicastInterface() const
+{
+    Q_D(const QNativeSocketEngine);
+    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::multicastInterface(), QNetworkInterface());
+    Q_CHECK_TYPE(QNativeSocketEngine::multicastInterface(), QAbstractSocket::UdpSocket, QNetworkInterface());
+    return d->nativeMulticastInterface();
+}
+
+
+/*! \since 4.8 */
+bool QNativeSocketEngine::setMulticastInterface(const QNetworkInterface &iface)
+{
+    Q_D(QNativeSocketEngine);
+    Q_CHECK_VALID_SOCKETLAYER(QNativeSocketEngine::setMulticastInterface(), false);
+    Q_CHECK_TYPE(QNativeSocketEngine::setMulticastInterface(), QAbstractSocket::UdpSocket, false);
+    return d->nativeSetMulticastInterface(iface);
+}
+
 /*!
     Returns the number of bytes that are currently available for
     reading. On error, -1 is returned.
diff --git a/src/network/socket/qnativesocketengine_p.h b/src/network/socket/qnativesocketengine_p.h
index ce00747..9baacf0 100644
--- a/src/network/socket/qnativesocketengine_p.h
+++ b/src/network/socket/qnativesocketengine_p.h
@@ -128,6 +128,8 @@ public:
                             const QNetworkInterface &iface);
     bool leaveMulticastGroup(const QHostAddress &groupAddress,
                              const QNetworkInterface &iface);
+    QNetworkInterface multicastInterface() const;
+    bool setMulticastInterface(const QNetworkInterface &iface);
 
     qint64 bytesAvailable() const;
 
@@ -247,6 +249,8 @@ public:
                                   const QNetworkInterface &iface);
     bool nativeLeaveMulticastGroup(const QHostAddress &groupAddress,
                                    const QNetworkInterface &iface);
+    QNetworkInterface nativeMulticastInterface() const;
+    bool nativeSetMulticastInterface(const QNetworkInterface &iface);
     qint64 nativeBytesAvailable() const;
 
     bool nativeHasPendingDatagrams() const;
diff --git a/src/network/socket/qnativesocketengine_unix.cpp b/src/network/socket/qnativesocketengine_unix.cpp
index 737e35a..e7f6c7e 100644
--- a/src/network/socket/qnativesocketengine_unix.cpp
+++ b/src/network/socket/qnativesocketengine_unix.cpp
@@ -249,12 +249,28 @@ int QNativeSocketEnginePrivate::option(QNativeSocketEngine::SocketOption opt) co
         n = SO_KEEPALIVE;
         break;
     case QNativeSocketEngine::MulticastTtlOption:
-        level = IPPROTO_IP;
-        n = IP_MULTICAST_TTL;
+#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:
-        level = IPPROTO_IP;
-        n = IP_MULTICAST_LOOP;
+#ifndef QT_NO_IPV6
+        if (socketProtocol == QAbstractSocket::IPv6Protocol) {
+            level = IPPROTO_IPV6;
+            n = IPV6_MULTICAST_LOOP;
+        } else
+#endif
+        {
+            level = IPPROTO_IP;
+            n = IP_MULTICAST_LOOP;
+        }
         break;
     }
 
@@ -340,12 +356,28 @@ bool QNativeSocketEnginePrivate::setOption(QNativeSocketEngine::SocketOption opt
         n = SO_KEEPALIVE;
         break;
     case QNativeSocketEngine::MulticastTtlOption:
-        level = IPPROTO_IP;
-        n = IP_MULTICAST_TTL;
+#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:
-        level = IPPROTO_IP;
-        n = IP_MULTICAST_LOOP;
+#ifndef QT_NO_IPV6
+        if (socketProtocol == QAbstractSocket::IPv6Protocol) {
+            level = IPPROTO_IPV6;
+            n = IPV6_MULTICAST_LOOP;
+        } else
+#endif
+        {
+            level = IPPROTO_IP;
+            n = IP_MULTICAST_LOOP;
+        }
         break;
     }
 
@@ -693,6 +725,69 @@ bool QNativeSocketEnginePrivate::nativeLeaveMulticastGroup(const QHostAddress &g
                                      interface);
 }
 
+QNetworkInterface QNativeSocketEnginePrivate::nativeMulticastInterface() const
+{
+#ifndef QT_NO_IPV6
+    if (socketProtocol == QAbstractSocket::IPv6Protocol) {
+        uint v;
+        QT_SOCKOPTLEN_T sizeofv = sizeof(v);
+        if (::getsockopt(socketDescriptor, IPPROTO_IPV6, IPV6_MULTICAST_IF, &v, &sizeofv) == -1)
+            return QNetworkInterface();
+        return QNetworkInterface::interfaceFromIndex(v);
+    }
+#endif
+
+    struct in_addr v = { 0 };
+    QT_SOCKOPTLEN_T sizeofv = sizeof(v);
+    if (::getsockopt(socketDescriptor, IPPROTO_IP, IP_MULTICAST_IF, &v, &sizeofv) == -1)
+        return QNetworkInterface();
+    if (v.s_addr != 0 && sizeofv >= sizeof(v)) {
+        QHostAddress ipv4(ntohl(v.s_addr));
+        QList<QNetworkInterface> ifaces = QNetworkInterface::allInterfaces();
+        for (int i = 0; i < ifaces.count(); ++i) {
+            const QNetworkInterface &iface = ifaces.at(i);
+            if (!(iface.flags() & QNetworkInterface::CanMulticast))
+                continue;
+            QList<QNetworkAddressEntry> entries = iface.addressEntries();
+            for (int j = 0; j < entries.count(); ++j) {
+                const QNetworkAddressEntry &entry = entries.at(j);
+                if (entry.ip() == ipv4)
+                    return iface;
+            }
+        }
+    }
+    return QNetworkInterface();
+}
+
+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, &v, sizeof(v)) != -1);
+    }
+#endif
+
+    struct in_addr v;
+    if (iface.isValid()) {
+        QList<QNetworkAddressEntry> entries = iface.addressEntries();
+        for (int i = 0; i < entries.count(); ++i) {
+            const QNetworkAddressEntry &entry = entries.at(i);
+            const QHostAddress &ip = entry.ip();
+            if (ip.protocol() == QAbstractSocket::IPv4Protocol) {
+                v.s_addr = htonl(ip.toIPv4Address());
+                int r = ::setsockopt(socketDescriptor, IPPROTO_IP, IP_MULTICAST_IF, &v, sizeof(v));
+                if (r != -1)
+                    return true;
+            }
+        }
+        return false;
+    }
+
+    v.s_addr = INADDR_ANY;
+    return (::setsockopt(socketDescriptor, IPPROTO_IP, IP_MULTICAST_IF, &v, sizeof(v)) != -1);
+}
+
 qint64 QNativeSocketEnginePrivate::nativeBytesAvailable() const
 {
     int nbytes = 0;
diff --git a/src/network/socket/qnativesocketengine_win.cpp b/src/network/socket/qnativesocketengine_win.cpp
index a922b45..2ca1f41 100644
--- a/src/network/socket/qnativesocketengine_win.cpp
+++ b/src/network/socket/qnativesocketengine_win.cpp
@@ -853,6 +853,69 @@ bool QNativeSocketEnginePrivate::nativeLeaveMulticastGroup(const QHostAddress &g
                                      iface);
 }
 
+QNetworkInterface QNativeSocketEnginePrivate::nativeMulticastInterface() const
+{
+#ifndef QT_NO_IPV6
+    if (socketProtocol == QAbstractSocket::IPv6Protocol) {
+        uint v;
+        QT_SOCKOPTLEN_T sizeofv = sizeof(v);
+        if (::getsockopt(socketDescriptor, IPPROTO_IPV6, IPV6_MULTICAST_IF, (char *) &v, &sizeofv) == -1)
+            return QNetworkInterface();
+        return QNetworkInterface::interfaceFromIndex(v);
+    }
+#endif
+
+    struct in_addr v = { 0 };
+    QT_SOCKOPTLEN_T sizeofv = sizeof(v);
+    if (::getsockopt(socketDescriptor, IPPROTO_IP, IP_MULTICAST_IF, (char *) &v, &sizeofv) == -1)
+        return QNetworkInterface();
+    if (v.s_addr != 0 && sizeofv >= sizeof(v)) {
+        QHostAddress ipv4(ntohl(v.s_addr));
+        QList<QNetworkInterface> ifaces = QNetworkInterface::allInterfaces();
+        for (int i = 0; i < ifaces.count(); ++i) {
+            const QNetworkInterface &iface = ifaces.at(i);
+            if (!(iface.flags() & QNetworkInterface::CanMulticast))
+                continue;
+            QList<QNetworkAddressEntry> entries = iface.addressEntries();
+            for (int j = 0; j < entries.count(); ++j) {
+                const QNetworkAddressEntry &entry = entries.at(j);
+                if (entry.ip() == ipv4)
+                    return iface;
+            }
+        }
+    }
+    return QNetworkInterface();
+}
+
+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()) {
+        QList<QNetworkAddressEntry> entries = iface.addressEntries();
+        for (int i = 0; i < entries.count(); ++i) {
+            const QNetworkAddressEntry &entry = entries.at(i);
+            const QHostAddress &ip = entry.ip();
+            if (ip.protocol() == QAbstractSocket::IPv4Protocol) {
+                v.s_addr = htonl(ip.toIPv4Address());
+                int r = ::setsockopt(socketDescriptor, IPPROTO_IP, IP_MULTICAST_IF, (char *) &v, sizeof(v));
+                if (r != -1)
+                    return true;
+            }
+        }
+        return false;
+    }
+
+    v.s_addr = INADDR_ANY;
+    return (::setsockopt(socketDescriptor, IPPROTO_IP, IP_MULTICAST_IF, (char *) &v, sizeof(v)) != -1);
+}
+
 qint64 QNativeSocketEnginePrivate::nativeBytesAvailable() const
 {
     unsigned long  nbytes = 0;
diff --git a/src/network/socket/qsocks5socketengine.cpp b/src/network/socket/qsocks5socketengine.cpp
index dcaf561..17cf5b1 100644
--- a/src/network/socket/qsocks5socketengine.cpp
+++ b/src/network/socket/qsocks5socketengine.cpp
@@ -56,6 +56,7 @@
 #include "qurl.h"
 #include "qauthenticator.h"
 #include <qendian.h>
+#include <qnetworkinterface.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -1560,6 +1561,19 @@ bool QSocks5SocketEngine::leaveMulticastGroup(const QHostAddress &,
     return false;
 }
 
+
+QNetworkInterface QSocks5SocketEngine::multicastInterface() const
+{
+    return QNetworkInterface();
+}
+
+bool QSocks5SocketEngine::setMulticastInterface(const QNetworkInterface &)
+{
+    setError(QAbstractSocket::UnsupportedSocketOperationError,
+             QLatin1String("Operation on socket is not supported"));
+    return false;
+}
+
 qint64 QSocks5SocketEngine::readDatagram(char *data, qint64 maxlen, QHostAddress *addr,
                                         quint16 *port)
 {
diff --git a/src/network/socket/qsocks5socketengine_p.h b/src/network/socket/qsocks5socketengine_p.h
index 298595a..06fcad2 100644
--- a/src/network/socket/qsocks5socketengine_p.h
+++ b/src/network/socket/qsocks5socketengine_p.h
@@ -96,6 +96,8 @@ public:
                             const QNetworkInterface &interface);
     bool leaveMulticastGroup(const QHostAddress &groupAddress,
                              const QNetworkInterface &interface);
+    QNetworkInterface multicastInterface() const;
+    bool setMulticastInterface(const QNetworkInterface &iface);
 
     qint64 readDatagram(char *data, qint64 maxlen, QHostAddress *addr = 0,
         quint16 *port = 0);
diff --git a/src/network/socket/qudpsocket.cpp b/src/network/socket/qudpsocket.cpp
index dffb5df..5d8f4c0 100644
--- a/src/network/socket/qudpsocket.cpp
+++ b/src/network/socket/qudpsocket.cpp
@@ -77,11 +77,12 @@
 
     \snippet doc/src/snippets/code/src_network_socket_qudpsocket.cpp 0
 
-    QUdpSocket also supports UDP multicast. Use the joinMulticastGroup() and
-    leaveMulticastGroup() to control group membership, and the
+    QUdpSocket also supports UDP multicast. Use joinMulticastGroup() and
+    leaveMulticastGroup() to control group membership, and
     QAbstractSocket::MulticastTtlOption and
     QAbstractSocket::MulticastLoopbackOption to set the TTL and loopback socket
-    options.
+    options. Use setMulticastInterface() to control the outgoing interface for
+    multicast datagrams, and multicastInterface() to query it.
 
     With QUdpSocket, you can also establish a virtual connection to a
     UDP server using connectToHost() and then use read() and write()
@@ -405,6 +406,45 @@ bool QUdpSocket::leaveMulticastGroup(const QHostAddress &groupAddress,
 }
 
 /*!
+    \since 4.8
+
+    Returns the interface for the outgoing interface for multicast datagrams.
+    This corresponds to the IP_MULTICAST_IF socket option for IPv4 sockets and
+    the IPV6_MULTICAST_IF socket option for IPv6 sockets. If no interface has
+    been previously set, this function returns an invalid QNetworkInterface.
+    The socket must be in BoundState, otherwise an invalid QNetworkInterface is
+    returned.
+
+    \sa setMulticastInterface()
+*/
+QNetworkInterface QUdpSocket::multicastInterface() const
+{
+    Q_D(const QUdpSocket);
+    QT_CHECK_BOUND("QUdpSocket::multicastInterface()", QNetworkInterface());
+    return d->socketEngine->multicastInterface();
+}
+
+/*!
+    \since 4.8
+
+    Sets the outgoing interface for multicast datagrams to the interface \a
+    iface. This corresponds to the IP_MULTICAST_IF socket option for IPv4
+    sockets and the IPV6_MULTICAST_IF socket option for IPv6 sockets. The
+    socket must be in BoundState, otherwise this function does nothing.
+
+    \sa multicastInterface(), joinMulticastGroup(), leaveMulticastGroup()
+*/
+void QUdpSocket::setMulticastInterface(const QNetworkInterface &iface)
+{
+    Q_D(QUdpSocket);
+    if (!isValid()) {
+        qWarning("QUdpSocket::setMulticastInterface() called on a QUdpSocket when not in QUdpSocket::BoundState");
+        return;
+    }
+    d->socketEngine->setMulticastInterface(iface);
+}
+
+/*!
     Returns true if at least one datagram is waiting to be read;
     otherwise returns false.
 
diff --git a/src/network/socket/qudpsocket.h b/src/network/socket/qudpsocket.h
index 54f82c9..b277d3f 100644
--- a/src/network/socket/qudpsocket.h
+++ b/src/network/socket/qudpsocket.h
@@ -84,6 +84,9 @@ public:
     bool leaveMulticastGroup(const QHostAddress &groupAddress,
                              const QNetworkInterface &iface);
 
+    QNetworkInterface multicastInterface() const;
+    void setMulticastInterface(const QNetworkInterface &iface);
+
     bool hasPendingDatagrams() const;
     qint64 pendingDatagramSize() const;
     qint64 readDatagram(char *data, qint64 maxlen, QHostAddress *host = 0, quint16 *port = 0);