1 files changed, 8 insertions, 0 deletions

diff --git a/noncore/net/wellenreiter/gui/wellenreiter.cpp b/noncore/net/wellenreiter/gui/wellenreiter.cpp
index db68e5b..67e3940 100644
--- a/noncore/net/wellenreiter/gui/wellenreiter.cpp
+++ b/noncore/net/wellenreiter/gui/wellenreiter.cpp
@@ -483,65 +483,73 @@ void Wellenreiter::stopClicked()
         QCopEnvelope( "QPE/System", "setScreenSaverMode(int)" ) << QPEApplication::Enable;
     }
     #else
         #warning FIXME: setScreenSaverMode is not operational on the X11 build
     #endif
 
     // print out statistics
     for( QMap<QString,int>::ConstIterator it = pcap->statistics().begin(); it != pcap->statistics().end(); ++it )
        statwindow->updateCounter( it.key(), it.data() );
 }
 
 
 void Wellenreiter::startClicked()
 {
     // get configuration from config window
 
     const QString& interface = configwindow->interfaceName->currentText();
     const int cardtype = configwindow->driverType();
     const int interval = configwindow->hoppingInterval();
 
     if ( ( interface == "" ) || ( cardtype == 0 ) )
     {
         QMessageBox::information( this, "Wellenreiter II",
                                   tr( "Your device is not\nproperly configured. Please reconfigure!" ) );
         return;
     }
 
     // configure device
     ONetwork* net = ONetwork::instance();
 
     // TODO: check if interface is wireless and support sniffing for non-wireless interfaces
 
+    if ( !net->isPresent( interface ) )
+    {
+        QMessageBox::information( this, "Wellenreiter II",
+                                  tr( "The configured device (%1)\nis not available on this system\n. Please reconfigure!" ).arg( interface ) );
+        return;
+    }
+
     iface = static_cast<OWirelessNetworkInterface*>(net->interface( interface )); // fails if network is not wireless!
+    assert( iface );
 
     // bring device UP
     if ( cardtype != DEVTYPE_FILE )
     {
         iface->setUp( true );
         if ( !iface->isUp() )
         {
             QMessageBox::warning( this, "Wellenreiter II",
                                 tr( "Can't bring interface '%1' up:\n" ).arg( iface->name() ) + strerror( errno ) );
             return;
         }
     }
     // set monitor mode
     bool usePrism = configwindow->usePrismHeader();
 
     switch ( cardtype )
     {
         case DEVTYPE_CISCO: iface->setMonitoring( new OCiscoMonitoringInterface( iface, usePrism ) ); break;
         case DEVTYPE_WLAN_NG: iface->setMonitoring( new OWlanNGMonitoringInterface( iface, usePrism ) ); break;
         case DEVTYPE_HOSTAP: iface->setMonitoring( new OHostAPMonitoringInterface( iface, usePrism ) ); break;
         case DEVTYPE_ORINOCO: iface->setMonitoring( new OOrinocoMonitoringInterface( iface, usePrism ) ); break;
         case DEVTYPE_MANUAL: QMessageBox::information( this, "Wellenreiter II", tr( "Bring your device into\nmonitor mode now." ) ); break;
         case DEVTYPE_FILE: qDebug( "Wellenreiter: Capturing from file '%s'", (const char*) interface ); break;
         default: assert( 0 ); // shouldn't reach this
     }
 
     // switch device into monitor mode
     if ( cardtype < DEVTYPE_FILE )
     {
         if ( cardtype != DEVTYPE_MANUAL )
             iface->setMode( "monitor" );
         if ( iface->mode() != "monitor" )