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/****************************************************************************
**
** 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)
{
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.connectionEncrypted())
crypto.sendShutdownAlert(&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(), '\0');
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);
if (crypto.connectionEncrypted()) {
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.connectionEncrypted()) {
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;
}
QT_END_NAMESPACE
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