QNetworkAccessManager: delay IPv4 connection with Happy Eyeballs

Incase we have both IPv4 and IPv6 available after the host lookup
we should delay the connection attempt to IPv4.

Task-number: QTBUG-23066
Change-Id: I8c0177cf125c9daae314ada73cacef790a39b856
Reviewed-by: Peter Hartmann <peter.hartmann@nokia.com>

src/network/access/qhttpnetworkconnection.cpp

@@ -116,6 +116,7 @@ QHttpNetworkConnectionPrivate::~QHttpNetworkConnectionPrivate()
 
 void QHttpNetworkConnectionPrivate::init()
 {
+    Q_Q(QHttpNetworkConnection);
     for (int i = 0; i < channelCount; i++) {
         channels[i].setConnection(this->q_func());
         channels[i].ssl = encrypt;
@@ -125,6 +126,8 @@ void QHttpNetworkConnectionPrivate::init()
 #endif
         channels[i].init();
     }
+    ipv4ConnectTimer.setSingleShot(true);
+    QObject::connect(&ipv4ConnectTimer, SIGNAL(timeout()), q, SLOT(_q_connectIPv4Channel()));
 }
 
 void QHttpNetworkConnectionPrivate::pauseConnection()
@@ -185,6 +188,12 @@ bool QHttpNetworkConnectionPrivate::shouldEmitChannelError(QAbstractSocket *sock
     int i = indexOf(socket);
     int otherSocket = (i == 0 ? 1 : 0);
 
+    // If the IPv4 connection still isn't started we need to start it now.
+    if (ipv4ConnectTimer.isActive()) {
+        ipv4ConnectTimer.stop();
+        channels[0].ensureConnection();
+    }
+
     if (channelCount == 1) {
         if (networkLayerState == QHttpNetworkConnectionPrivate::InProgress)
             networkLayerState = QHttpNetworkConnectionPrivate::Unknown;
@@ -1010,7 +1019,18 @@ void QHttpNetworkConnectionPrivate::startNetworkLayerStateLookup()
         channels[0].networkLayerPreference = QAbstractSocket::IPv4Protocol;
         channels[1].networkLayerPreference = QAbstractSocket::IPv6Protocol;
 
-        channels[0].ensureConnection(); // Possibly delay this one..
+        int timeout = 300;
+#ifndef QT_NO_BEARERMANAGEMENT
+        if (networkSession->configuration().bearerType() == QNetworkConfiguration::Bearer2G)
+            timeout = 800;
+        else if (networkSession->configuration().bearerType() == QNetworkConfiguration::BearerCDMA2000)
+            timeout = 500;
+        else if (networkSession->configuration().bearerType() == QNetworkConfiguration::BearerWCDMA)
+            timeout = 500;
+        else if (networkSession->configuration().bearerType() == QNetworkConfiguration::BearerHSPA)
+            timeout = 400;
+#endif
+        ipv4ConnectTimer.start(timeout);
         channels[1].ensureConnection();
     } else {
         networkLayerState = InProgress;
@@ -1019,6 +1039,10 @@ void QHttpNetworkConnectionPrivate::startNetworkLayerStateLookup()
     }
 }
 
+void QHttpNetworkConnectionPrivate::_q_connectIPv4Channel()
+{
+    channels[0].ensureConnection();
+}
 
 #ifndef QT_NO_BEARERMANAGEMENT
 QHttpNetworkConnection::QHttpNetworkConnection(const QString &hostName, quint16 port, bool encrypt, QObject *parent, QSharedPointer<QNetworkSession> networkSession)

src/network/access/qhttpnetworkconnection_p.h

@@ -61,6 +61,7 @@
 #include <qauthenticator.h>
 #include <qnetworkproxy.h>
 #include <qbuffer.h>
+#include <qtimer.h>
 
 #include <private/qhttpnetworkheader_p.h>
 #include <private/qhttpnetworkrequest_p.h>
@@ -134,6 +135,7 @@ private:
 
     Q_PRIVATE_SLOT(d_func(), void _q_startNextRequest())
     Q_PRIVATE_SLOT(d_func(), void _q_hostLookupFinished(QHostInfo))
+    Q_PRIVATE_SLOT(d_func(), void _q_connectIPv4Channel())
 };
 
 
@@ -196,6 +198,7 @@ public:
     void _q_startNextRequest(); // send the next request from the queue
 
     void _q_hostLookupFinished(QHostInfo info);
+    void _q_connectIPv4Channel();
 
     void createAuthorization(QAbstractSocket *socket, QHttpNetworkRequest &request);
 
@@ -209,6 +212,7 @@ public:
     bool encrypt;
 
     const int channelCount;
+    QTimer ipv4ConnectTimer;
     QHttpNetworkConnectionChannel *channels; // parallel connections to the server
     bool shouldEmitChannelError(QAbstractSocket *socket);
 

src/network/access/qhttpnetworkconnectionchannel.cpp

@@ -951,6 +951,8 @@ void QHttpNetworkConnectionChannel::_q_connected()
     // For the Happy Eyeballs we need to check if this is the first channel to connect.
     if (!pendingEncrypt) {
         if (connection->d_func()->networkLayerState == QHttpNetworkConnectionPrivate::InProgress) {
+            if (connection->d_func()->ipv4ConnectTimer.isActive())
+                connection->d_func()->ipv4ConnectTimer.stop();
             if (networkLayerPreference == QAbstractSocket::IPv4Protocol)
                 connection->d_func()->networkLayerState = QHttpNetworkConnectionPrivate::IPv4;
             else if (networkLayerPreference == QAbstractSocket::IPv6Protocol)