backends/lan/landevicelink.cpp

/**
 * SPDX-FileCopyrightText: 2013 Albert Vaca <albertvaka@gmail.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
 */

#include "landevicelink.h"

#include <KLocalizedString>

#include "core_debug.h"
#include "kdeconnectconfig.h"
#include "backends/linkprovider.h"
#include "socketlinereader.h"
#include "lanlinkprovider.h"
#include "plugins/share/shareplugin.h"

LanDeviceLink::LanDeviceLink(const QString& deviceId, LinkProvider* parent, QSslSocket* socket, ConnectionStarted connectionSource)
    : DeviceLink(deviceId, parent)
    , m_socketLineReader(nullptr)
{
    reset(socket, connectionSource);
}

void LanDeviceLink::reset(QSslSocket* socket, ConnectionStarted connectionSource)
{
    if (m_socketLineReader) {
        disconnect(m_socketLineReader->m_socket, &QAbstractSocket::disconnected, this, &QObject::deleteLater);
        delete m_socketLineReader;
    }

    m_socketLineReader = new SocketLineReader(socket, this);

    connect(socket, &QAbstractSocket::disconnected, this, &QObject::deleteLater);
    connect(m_socketLineReader, &SocketLineReader::readyRead, this, &LanDeviceLink::dataReceived);

    //We take ownership of the socket.
    //When the link provider destroys us,
    //the socket (and the reader) will be
    //destroyed as well
    socket->setParent(m_socketLineReader);

    m_connectionSource = connectionSource;

    QString certString = KdeConnectConfig::instance().getDeviceProperty(deviceId(), QStringLiteral("certificate"));
    DeviceLink::setPairStatus(certString.isEmpty()? PairStatus::NotPaired : PairStatus::Paired);
}

QHostAddress LanDeviceLink::hostAddress() const
{
    if (!m_socketLineReader) {
        return QHostAddress::Null;
    }
    QHostAddress addr = m_socketLineReader->m_socket->peerAddress();
    if (addr.protocol() == QAbstractSocket::IPv6Protocol) {
        bool success;
        QHostAddress convertedAddr = QHostAddress(addr.toIPv4Address(&success));
        if (success) {
            qCDebug(KDECONNECT_CORE) << "Converting IPv6" << addr << "to IPv4" << convertedAddr;
            addr = convertedAddr;
        }
    }
    return addr;
}

QString LanDeviceLink::name()
{
    return QStringLiteral("LanLink"); // Should be same in both android and kde version
}

bool LanDeviceLink::sendPacket(NetworkPacket& np)
{
    if (np.payload()) {
        if (np.type() == PACKET_TYPE_SHARE_REQUEST && np.payloadSize() >= 0) {
            if (!m_compositeUploadJob || !m_compositeUploadJob->isRunning()) {
                m_compositeUploadJob = new CompositeUploadJob(deviceId(), true);
            }

            m_compositeUploadJob->addSubjob(new UploadJob(np));

            if (!m_compositeUploadJob->isRunning()) {
                m_compositeUploadJob->start();
            }
        } else { //Infinite stream
            CompositeUploadJob* fireAndForgetJob = new CompositeUploadJob(deviceId(), false);
            fireAndForgetJob->addSubjob(new UploadJob(np));
            fireAndForgetJob->start();
        }

        return true;
    } else {
        int written = m_socketLineReader->write(np.serialize());

        //Actually we can't detect if a packet is received or not. We keep TCP
        //"ESTABLISHED" connections that look legit (return true when we use them),
        //but that are actually broken (until keepalive detects that they are down).
        return (written != -1);
    }
}

void LanDeviceLink::dataReceived()
{
    if (!m_socketLineReader->hasPacketsAvailable()) return;

    const QByteArray serializedPacket = m_socketLineReader->readLine();
    NetworkPacket packet((QString()));
    NetworkPacket::unserialize(serializedPacket, &packet);

    //qCDebug(KDECONNECT_CORE) << "LanDeviceLink dataReceived" << serializedPacket;

    if (packet.type() == PACKET_TYPE_PAIR) {
        //TODO: Handle pair/unpair requests and forward them (to the pairing handler?)
        qobject_cast<LanLinkProvider*>(provider())->incomingPairPacket(this, packet);
        return;
    }

    if (packet.hasPayloadTransferInfo()) {
        //qCDebug(KDECONNECT_CORE) << "HasPayloadTransferInfo";
        const QVariantMap transferInfo = packet.payloadTransferInfo();

        QSharedPointer<QSslSocket> socket(new QSslSocket);

        LanLinkProvider::configureSslSocket(socket.data(), deviceId(), true);

        // emit readChannelFinished when the socket gets disconnected. This seems to be a bug in upstream QSslSocket.
        // Needs investigation and upstreaming of the fix. QTBUG-62257
        connect(socket.data(), &QAbstractSocket::disconnected, socket.data(), &QAbstractSocket::readChannelFinished);

        const QString address = m_socketLineReader->peerAddress().toString();
        const quint16 port = transferInfo[QStringLiteral("port")].toInt();
        socket->connectToHostEncrypted(address, port, QIODevice::ReadWrite);
        packet.setPayload(socket, packet.payloadSize());
    }

    Q_EMIT receivedPacket(packet);

    if (m_socketLineReader->hasPacketsAvailable()) {
        QMetaObject::invokeMethod(this, "dataReceived", Qt::QueuedConnection);
    }

}

void LanDeviceLink::userRequestsPair()
{
    if (m_socketLineReader->peerCertificate().isNull()) {
        Q_EMIT pairingError(i18n("This device cannot be paired because it is running an old version of KDE Connect."));
    } else {
        qobject_cast<LanLinkProvider*>(provider())->userRequestsPair(deviceId());
    }
}

void LanDeviceLink::userRequestsUnpair()
{
    qobject_cast<LanLinkProvider*>(provider())->userRequestsUnpair(deviceId());
}

void LanDeviceLink::setPairStatus(PairStatus status)
{
    if (status == Paired && m_socketLineReader->peerCertificate().isNull()) {
        Q_EMIT pairingError(i18n("This device cannot be paired because it is running an old version of KDE Connect."));
        return;
    }

    DeviceLink::setPairStatus(status);
    if (status == Paired) {
        Q_ASSERT(KdeConnectConfig::instance().trustedDevices().contains(deviceId()));
        KdeConnectConfig::instance().setDeviceProperty(deviceId(), QStringLiteral("certificate"), QString::fromLatin1(certificate().toPem()));
    }
}

bool LanDeviceLink::linkShouldBeKeptAlive() {

    return true;     //FIXME: Current implementation is broken, so for now we will keep links always established

    //We keep the remotely initiated connections, since the remotes require them if they want to request
    //pairing to us, or connections that are already paired. TODO: Keep connections in the process of pairing
    //return (mConnectionSource == ConnectionStarted::Remotely || pairStatus() == Paired);

}

QSslCertificate LanDeviceLink::certificate() const
{
    return m_socketLineReader->peerCertificate();
}