Determine which IP address to use for sshfs

Summary:
There is currently an issue where the device doesn't send the correct IP address for sshfs when a VPN is present.

Instead of asking the device to find and send its address, we can store it from when the device link is created then reuse it.

Test Plan:
All unit tests pass.

In these different situations:
  - without a VPN
  - with a VPN running
  - with a VPN started then stopped (the tun interface might still be there)
Try to remotely browse the device. It should work in all cases.

Reviewers: #kde_connect, albertvaka

Reviewed By: #kde_connect, albertvaka

Subscribers: albertvaka, apol, nicolasfella, sredman

Tags: #kde_connect

Differential Revision: https://phabricator.kde.org/D6730

core/backends/lan/landevicelink.cpp

@@ -56,6 +56,9 @@ void LanDeviceLink::reset(QSslSocket* socket, ConnectionStarted connectionSource
 
     mConnectionSource = connectionSource;
 
+    QHostAddress addr = socket->peerAddress();
+    mHostAddress = (addr.protocol() == QAbstractSocket::IPv6Protocol) ? QHostAddress(addr.toIPv4Address()) : addr;
+
     QString certString = KdeConnectConfig::instance()->getDeviceProperty(deviceId(), QStringLiteral("certificate"));
     DeviceLink::setPairStatus(certString.isEmpty()? PairStatus::NotPaired : PairStatus::Paired);
 }

core/backends/lan/landevicelink.h

@@ -54,12 +54,15 @@ public:
 
     bool linkShouldBeKeptAlive() override;
 
+    QHostAddress hostAddress() const { return mHostAddress; }
+
 private Q_SLOTS:
     void dataReceived();
 
 private:
     SocketLineReader* mSocketLineReader;
     ConnectionStarted mConnectionSource;
+    QHostAddress mHostAddress;
 };
 
 #endif

core/device.cpp

@@ -35,6 +35,7 @@
 #include "kdeconnectplugin.h"
 #include "pluginloader.h"
 #include "backends/devicelink.h"
+#include "backends/lan/landevicelink.h"
 #include "backends/linkprovider.h"
 #include "networkpackage.h"
 #include "kdeconnectconfig.h"
@@ -380,6 +381,17 @@ void Device::cleanUnneededLinks() {
     }
 }
 
+QHostAddress Device::getLocalIpAddress() const
+{
+    for (DeviceLink* dl : m_deviceLinks) {
+        LanDeviceLink* ldl = dynamic_cast<LanDeviceLink*>(dl);
+        if (ldl) {
+            return ldl->hostAddress();
+        }
+    }
+    return QHostAddress::Null;
+}
+
 Device::DeviceType Device::str2type(const QString &deviceType) {
     if (deviceType == QLatin1String("desktop")) return Desktop;
     if (deviceType == QLatin1String("laptop")) return Laptop;

core/device.h

@@ -25,6 +25,7 @@
 #include <QString>
 #include <QVector>
 #include <QSet>
+#include <QHostAddress>
 
 #include "networkpackage.h"
 #include "backends/devicelink.h"
@@ -103,6 +104,8 @@ public:
     int protocolVersion() { return m_protocolVersion; }
     QStringList supportedPlugins() const { return m_supportedPlugins.toList(); }
 
+    QHostAddress getLocalIpAddress() const;
+
 public Q_SLOTS:
     ///sends a @p np package to the device
     ///virtual for testing purposes.

plugins/sftp/mounter.cpp

@@ -113,10 +113,17 @@ void Mounter::onPakcageReceived(const NetworkPackage& np)
     if (np.has(QStringLiteral("multiPaths"))) path = '/';
     else path = np.get<QString>(QStringLiteral("path"));
 
+    QHostAddress addr = m_sftp->device()->getLocalIpAddress();
+    if (addr == QHostAddress::Null) {
+        qCDebug(KDECONNECT_PLUGIN_SFTP) << "Device doesn't have a LanDeviceLink, unable to get IP address";
+        return;
+    }
+    QString ip = addr.toString();
+
     const QStringList arguments = QStringList()
         << QStringLiteral("%1@%2:%3").arg(
             np.get<QString>(QStringLiteral("user")),
-            np.get<QString>(QStringLiteral("ip")),
+            ip,
             path)
         << m_mountPoint
         << QStringLiteral("-p") << np.get<QString>(QStringLiteral("port"))