association.cpp Example File

/**************************************************************************** ** ** Copyright (C) 2018 The Qt Company Ltd. ** Contact: ** ** 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 For further ** information use the contact form at ** ** 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" DtlsAssociation::DtlsAssociation(const QHostAddress &address, quint16 port, const QString &connectionName) : name(connectionName), crypto(QSslSocket::SslClientMode) { auto configuration = QSslConfiguration::defaultDtlsConfiguration(); configuration.setPeerVerifyMode(QSslSocket::VerifyNone); crypto.setPeer(address, port); crypto.setDtlsConfiguration(configuration); connect(&crypto, &QDtls::handshakeTimeout, this, &DtlsAssociation::handshakeTimeout); connect(&crypto, &QDtls::pskRequired, this, &DtlsAssociation::pskRequired); socket.connectToHost(address.toString(), port); connect(&socket, &QUdpSocket::readyRead, this, &DtlsAssociation::readyRead); pingTimer.setInterval(5000); connect(&pingTimer, &QTimer::timeout, this, &DtlsAssociation::pingTimeout); } DtlsAssociation::~DtlsAssociation() { if (crypto.isConnectionEncrypted()) crypto.shutdown(&socket); } 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)); } void DtlsAssociation::udpSocketConnected() { emit infoMessage(tr("%1: UDP socket is now in ConnectedState, continue with handshake ...").arg(name)); startHandshake(); } void DtlsAssociation::readyRead() { QByteArray dgram(socket.pendingDatagramSize(), Qt::Uninitialized); const qint64 bytesRead = socket.readDatagram(, dgram.size()); if (bytesRead <= 0) { emit warningMessage(tr("%1: spurious read notification?").arg(name)); return; } dgram.resize(bytesRead); 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 { if (!crypto.doHandshake(&socket, dgram)) { emit errorMessage(tr("%1: handshake error - %2").arg(name, crypto.dtlsErrorString())); return; } if (crypto.isConnectionEncrypted()) { emit infoMessage(tr("%1: encrypted connection established!").arg(name)); pingTimer.start(); pingTimeout(); } else { emit infoMessage(tr("%1: continuing with handshake ...").arg(name)); } } } 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())); } 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")); } 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; }

© 2018 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.