1 files changed, 197 insertions, 0 deletions
diff --git a/examples/network/secureudpclient/association.cpp b/examples/network/secureudpclient/association.cpp
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+++ b/examples/network/secureudpclient/association.cpp
@@ -0,0 +1,197 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "association.h"
+
+QT_BEGIN_NAMESPACE
+
+DtlsAssociation::DtlsAssociation(const QHostAddress &address, quint16 port,
+                                 const QString &connectionName)
+    : name(connectionName),
+      crypto(QSslSocket::SslClientMode)
+{
+    //! [1]
+    auto configuration = QSslConfiguration::defaultDtlsConfiguration();
+    configuration.setPeerVerifyMode(QSslSocket::VerifyNone);
+    crypto.setPeer(address, port);
+    crypto.setDtlsConfiguration(configuration);
+    //! [1]
+
+    //! [2]
+    connect(&crypto, &QDtls::handshakeTimeout, this, &DtlsAssociation::handshakeTimeout);
+    //! [2]
+    connect(&crypto, &QDtls::pskRequired, this, &DtlsAssociation::pskRequired);
+    //! [3]
+    socket.connectToHost(address.toString(), port);
+    //! [3]
+    //! [13]
+    connect(&socket, &QUdpSocket::readyRead, this, &DtlsAssociation::readyRead);
+    //! [13]
+    //! [4]
+    pingTimer.setInterval(5000);
+    connect(&pingTimer, &QTimer::timeout, this, &DtlsAssociation::pingTimeout);
+    //! [4]
+}
+
+//! [12]
+DtlsAssociation::~DtlsAssociation()
+{
+    if (crypto.isConnectionEncrypted())
+        crypto.shutdown(&socket);
+}
+//! [12]
+
+//! [5]
+void DtlsAssociation::startHandshake()
+{
+    if (socket.state() != QAbstractSocket::ConnectedState) {
+        emit infoMessage(tr("%1: connecting UDP socket first ...").arg(name));
+        connect(&socket, &QAbstractSocket::connected, this, &DtlsAssociation::udpSocketConnected);
+        return;
+    }
+
+    if (!crypto.doHandshake(&socket))
+        emit errorMessage(tr("%1: failed to start a handshake - %2").arg(name, crypto.dtlsErrorString()));
+    else
+        emit infoMessage(tr("%1: starting a handshake").arg(name));
+}
+//! [5]
+
+void DtlsAssociation::udpSocketConnected()
+{
+    emit infoMessage(tr("%1: UDP socket is now in ConnectedState, continue with handshake ...").arg(name));
+    startHandshake();
+}
+
+void DtlsAssociation::readyRead()
+{
+    //! [6]
+    QByteArray dgram(socket.pendingDatagramSize(), Qt::Uninitialized);
+    const qint64 bytesRead = socket.readDatagram(dgram.data(), dgram.size());
+    if (bytesRead <= 0) {
+        emit warningMessage(tr("%1: spurious read notification?").arg(name));
+        return;
+    }
+
+    dgram.resize(bytesRead);
+    //! [6]
+    //! [7]
+    if (crypto.isConnectionEncrypted()) {
+        const QByteArray plainText = crypto.decryptDatagram(&socket, dgram);
+        if (plainText.size()) {
+            emit serverResponse(name, dgram, plainText);
+            return;
+        }
+
+        if (crypto.dtlsError() == QDtlsError::RemoteClosedConnectionError) {
+            emit errorMessage(tr("%1: shutdown alert received").arg(name));
+            socket.close();
+            pingTimer.stop();
+            return;
+        }
+
+        emit warningMessage(tr("%1: zero-length datagram received?").arg(name));
+    } else {
+    //! [7]
+    //! [8]
+        if (!crypto.doHandshake(&socket, dgram)) {
+            emit errorMessage(tr("%1: handshake error - %2").arg(name, crypto.dtlsErrorString()));
+            return;
+        }
+    //! [8]
+
+    //! [9]
+        if (crypto.isConnectionEncrypted()) {
+            emit infoMessage(tr("%1: encrypted connection established!").arg(name));
+            pingTimer.start();
+            pingTimeout();
+        } else {
+    //! [9]
+            emit infoMessage(tr("%1: continuing with handshake ...").arg(name));
+        }
+    }
+}
+
+//! [11]
+void DtlsAssociation::handshakeTimeout()
+{
+    emit warningMessage(tr("%1: handshake timeout, trying to re-transmit").arg(name));
+    if (!crypto.handleTimeout(&socket))
+        emit errorMessage(tr("%1: failed to re-transmit - %2").arg(name, crypto.dtlsErrorString()));
+}
+//! [11]
+
+//! [14]
+void DtlsAssociation::pskRequired(QSslPreSharedKeyAuthenticator *auth)
+{
+    Q_ASSERT(auth);
+
+    emit infoMessage(tr("%1: providing pre-shared key ...").arg(name));
+    auth->setIdentity(name.toLatin1());
+    auth->setPreSharedKey(QByteArrayLiteral("\x1a\x2b\x3c\x4d\x5e\x6f"));
+}
+//! [14]
+
+//! [10]
+void DtlsAssociation::pingTimeout()
+{
+    static const QString message = QStringLiteral("I am %1, please, accept our ping %2");
+    const qint64 written = crypto.writeDatagramEncrypted(&socket, message.arg(name).arg(ping).toLatin1());
+    if (written <= 0) {
+        emit errorMessage(tr("%1: failed to send a ping - %2").arg(name, crypto.dtlsErrorString()));
+        pingTimer.stop();
+        return;
+    }
+
+    ++ping;
+}
+//! [10]
+
+QT_END_NAMESPACE