add sanity check for last packet when capturing from capture file

1 files changed, 2 insertions, 1 deletions

diff --git a/libopie2/opienet/opcap.cpp b/libopie2/opienet/opcap.cpp
index 04b1bb1..e362883 100644
--- a/libopie2/opienet/opcap.cpp
+++ b/libopie2/opienet/opcap.cpp
@@ -1,966 +1,967 @@
 /*
                              This file is part of the Opie Project
                              Copyright (C) 2003 by the Wellenreiter team:
                              Martin J. Muench <mjm@remote-exploit.org>
                              Max Moser <mmo@remote-exploit.org
                              Michael 'Mickey' Lauer <mickey@tm.informatik.uni-frankfurt.de>
               =.
             .=l.
            .>+-=
  _;:,     .>    :=|.         This program is free software; you can
 .> <`_,   >  .   <=          redistribute it and/or  modify it under
 :`=1 )Y*s>-.--   :           the terms of the GNU Library General Public
 .="- .-=="i,     .._         License as published by the Free Software
  - .   .-<_>     .<>         Foundation; either version 2 of the License,
      ._= =}       :          or (at your option) any later version.
     .%`+i>       _;_.
     .i_,=:_.      -<s.       This program is distributed in the hope that
      +  .  -:.       =       it will be useful,  but WITHOUT ANY WARRANTY;
     : ..    .:,     . . .    without even the implied warranty of
     =_        +     =;=|`    MERCHANTABILITY or FITNESS FOR A
   _.=:.       :    :=>`:     PARTICULAR PURPOSE. See the GNU
 ..}^=.=       =       ;      Library General Public License for more
 ++=   -.     .`     .:       details.
  :     =  ...= . :.=-
  -.   .:....=;==+<;          You should have received a copy of the GNU
   -_. . .   )=.  =           Library General Public License along with
     --        :-=`           this library; see the file COPYING.LIB.
                              If not, write to the Free Software Foundation,
                              Inc., 59 Temple Place - Suite 330,
                              Boston, MA 02111-1307, USA.
 
 */
 
 /* OPIE */
 
 #include <opie2/opcap.h>
 
 /* QT */
 
 #include <qapplication.h> // don't use oapplication here (will decrease reusability in other projects)
 #include <qsocketnotifier.h>
 #include <qobjectlist.h>
 
 /*======================================================================================
  * OPacket
  *======================================================================================*/
 
 OPacket::OPacket( int datalink, packetheaderstruct header, const unsigned char* data, QObject* parent )
         :QObject( parent, "Generic" ), _hdr( header ), _data( data )
 {
     //qDebug( "OPacket::OPacket(): (Len %d, CapLen %d)" /*, ctime((const time_t*) header.ts.tv_sec)*/, header.len, header.caplen );
 
     _end = (unsigned char*) data + header.len;
     //qDebug( "OPacket::data @ %0x, end @ %0x", data, _end );
 
     switch ( datalink )
     {
         case DLT_EN10MB:
             qDebug( "OPacket::OPacket(): Received Packet. Datalink = ETHERNET" );
             new OEthernetPacket( _end, (const struct ether_header*) data, this );
             break;
 
         case DLT_IEEE802_11:
             qDebug( "OPacket::OPacket(): Received Packet. Datalink = IEEE802.11" );
             new OWaveLanPacket( _end, (const struct ieee_802_11_header*) data, this );
             break;
 
         default:
             qWarning( "OPacket::OPacket(): Received Packet over unsupported datalink '%s'!", datalink );
     }
 }
 
 
 OPacket::~OPacket()
 {
 }
 
 
 timevalstruct OPacket::timeval() const
 {
     return _hdr.ts;
 }
 
 
 int OPacket::caplen() const
 {
     return _hdr.caplen;
 }
 
 
 void OPacket::updateStats( QMap<QString,int>& stats, QObjectList* l )
 {
     if (!l) return;
     QObject* o = l->first();
     while ( o )
     {
         stats[o->name()]++;
         updateStats( stats, const_cast<QObjectList*>( o->children() ) );
         o = l->next();
     }
 }
 
 
 QString OPacket::dump( int bpl ) const
 {
     static int index = 0;
     index++;
     int len = _hdr.caplen;
     QString str;
     str.sprintf( "\n<----- Packet #%04d Len = 0x%X (%d) ----->\n\n", index, len, len );
     str.append( "0000: " );
     QString tmp;
     QString bytes;
     QString chars;
 
     for ( int i = 0; i < len; ++i )
     {
         tmp.sprintf( "%02X ", _data[i] ); bytes.append( tmp );
         if ( (_data[i] > 31) && (_data[i]<128) ) chars.append( _data[i] );
         else chars.append( '.' );
 
         if ( !((i+1) % bpl) )
         {
             str.append( bytes );
             str.append( ' ' );
             str.append( chars );
             str.append( '\n' );
             tmp.sprintf( "%04X: ", i+1 ); str.append( tmp );
             bytes = "";
             chars = "";
         }
 
     }
     if ( (len % bpl) )
     {
         str.append( bytes.leftJustify( 1 + 3*bpl ) );
         str.append( chars );
     }
     str.append( '\n' );
     return str;
 }
 
 
 int OPacket::len() const
 {
     return _hdr.len;
 }
 
 
 /*======================================================================================
  * OEthernetPacket
  *======================================================================================*/
 
 OEthernetPacket::OEthernetPacket( const unsigned char* end, const struct ether_header* data, QObject* parent )
                 :QObject( parent, "Ethernet" ), _ether( data )
 
 {
 
     qDebug( "Source = %s", (const char*) sourceAddress().toString() );
     qDebug( "Destination = %s", (const char*) destinationAddress().toString() );
 
     if ( sourceAddress() == OMacAddress::broadcast )
         qDebug( "Source is broadcast address" );
     if ( destinationAddress() == OMacAddress::broadcast )
         qDebug( "Destination is broadcast address" );
 
     switch ( type() )
     {
         case ETHERTYPE_IP: new OIPPacket( end, (const struct iphdr*) (data+1), this ); break;
         case ETHERTYPE_ARP: { qDebug( "OPacket::OPacket(): Received Ethernet Packet : Type = ARP" ); break; }
         case ETHERTYPE_REVARP: { qDebug( "OPacket::OPacket(): Received Ethernet Packet : Type = RARP" ); break; }
         default: qDebug( "OPacket::OPacket(): Received Ethernet Packet : Type = UNKNOWN" );
     }
 
 }
 
 
 OEthernetPacket::~OEthernetPacket()
 {
 }
 
 
 OMacAddress OEthernetPacket::sourceAddress() const
 {
     return OMacAddress( _ether->ether_shost );
 }
 
 
 OMacAddress OEthernetPacket::destinationAddress() const
 {
     return OMacAddress( _ether->ether_dhost );
 }
 
 int OEthernetPacket::type() const
 {
     return ntohs( _ether->ether_type );
 }
 
 
 /*======================================================================================
  * OIPPacket
  *======================================================================================*/
 
 
 OIPPacket::OIPPacket( const unsigned char* end, const struct iphdr* data, QObject* parent )
           :QObject( parent, "IP" ), _iphdr( data )
 
 {
     qDebug( "OIPPacket::OIPPacket(): decoding IP header..." );
 
     //qDebug( "FromAddress: %s", (const char*) inet_ntoa( *src ) );
     //qDebug( "  ToAddress: %s", (const char*) inet_ntoa( *dst ) );
 
     qDebug( "FromAddress: %s", (const char*) fromIPAddress().toString() );
     qDebug( "  toAddress: %s", (const char*) toIPAddress().toString() );
 
     switch ( protocol() )
     {
         case IPPROTO_UDP: new OUDPPacket( end, (const struct udphdr*) (data+1), this ); break;
         case IPPROTO_TCP: new OTCPPacket( end, (const struct tcphdr*) (data+1), this ); break;
         default: qDebug( "OIPPacket::OIPPacket(): unknown IP protocol type = %d", protocol() );
     }
 
 }
 
 OIPPacket::~OIPPacket()
 {
 }
 
 
 QHostAddress OIPPacket::fromIPAddress() const
 {
     return EXTRACT_32BITS( &_iphdr->saddr );
 }
 
 
 QHostAddress OIPPacket::toIPAddress() const
 {
     return EXTRACT_32BITS( &_iphdr->saddr );
 }
 
 
 int OIPPacket::tos() const
 {
     return _iphdr->tos;
 }
 
 
 int OIPPacket::len() const
 {
     return EXTRACT_16BITS( &_iphdr->tot_len );
 }
 
 
 int OIPPacket::id() const
 {
     return EXTRACT_16BITS( &_iphdr->id );
 }
 
 
 int OIPPacket::offset() const
 {
     return EXTRACT_16BITS( &_iphdr->frag_off );
 }
 
 
 int OIPPacket::ttl() const
 {
     return _iphdr->ttl;
 }
 
 
 int OIPPacket::protocol() const
 {
     return _iphdr->protocol;
 }
 
 
 int OIPPacket::checksum() const
 {
     return EXTRACT_16BITS( &_iphdr->check );
 }
 
 /*======================================================================================
  * OUDPPacket
  *======================================================================================*/
 
 
 OUDPPacket::OUDPPacket( const unsigned char* end, const struct udphdr* data, QObject* parent )
            :QObject( parent, "UDP" ), _udphdr( data )
 
 {
     qDebug( "OUDPPacket::OUDPPacket(): decoding UDP header..." );
 }
 
 OUDPPacket::~OUDPPacket()
 {
 }
 
 
 /*======================================================================================
  * OTCPPacket
  *======================================================================================*/
 
 
 OTCPPacket::OTCPPacket( const unsigned char* end, const struct tcphdr* data, QObject* parent )
            :QObject( parent, "TCP" ), _tcphdr( data )
 
 {
     qDebug( "OTCPPacket::OTCPPacket(): decoding TCP header..." );
 }
 
 OTCPPacket::~OTCPPacket()
 {
 }
 
 
 /*======================================================================================
  * OWaveLanPacket
  *======================================================================================*/
 
 
 OWaveLanPacket::OWaveLanPacket( const unsigned char* end, const struct ieee_802_11_header* data, QObject* parent )
                 :QObject( parent, "802.11" ), _wlanhdr( data )
 
 {
     qDebug( "OWaveLanPacket::OWaveLanPacket(): decoding IEEE 802.11 header..." );
     qDebug( "type: %0X", type() );
     qDebug( "subType: %0X", subType() );
     qDebug( "duration: %d", duration() );
     qDebug( "powermanagement: %d", usesPowerManagement() );
     qDebug( "payload is encrypted: %s", usesWep() ? "yes" : "no" );
     qDebug( "MAC1: %s", (const char*) macAddress1().toString() );
     qDebug( "MAC2: %s", (const char*) macAddress2().toString() );
     qDebug( "MAC3: %s", (const char*) macAddress3().toString() );
     qDebug( "MAC4: %s", (const char*) macAddress4().toString() );
 
     switch ( type() )
     {
         case T_MGMT: new OWaveLanManagementPacket( end, (const struct ieee_802_11_mgmt_header*) data, this ); break;
         case T_DATA: new OWaveLanDataPacket( end, (const struct ieee_802_11_data_header*) data, this ); break;
         case T_CTRL: new OWaveLanControlPacket( end, (const struct ieee_802_11_control_header*) data, this ); break;
         default: qDebug( "OWaveLanPacket::OWaveLanPacket(): Warning: Unknown major type '%d'!", type() );
     }
 }
 
 OWaveLanPacket::~OWaveLanPacket()
 {
 }
 
 
 int OWaveLanPacket::duration() const
 {
     return _wlanhdr->duration;
 }
 
 
 OMacAddress OWaveLanPacket::macAddress1() const
 {
     return OMacAddress( _wlanhdr->mac1 );
 }
 
 
 OMacAddress OWaveLanPacket::macAddress2() const
 {
     return OMacAddress( _wlanhdr->mac2 );
 }
 
 
 OMacAddress OWaveLanPacket::macAddress3() const
 {
     return OMacAddress( _wlanhdr->mac3 );
 }
 
 
 OMacAddress OWaveLanPacket::macAddress4() const
 {
     return OMacAddress( _wlanhdr->mac4 );
 }
 
 
 int OWaveLanPacket::subType() const
 {
     return FC_SUBTYPE( EXTRACT_LE_16BITS( &_wlanhdr->frame_control ) );
 }
 
 
 int OWaveLanPacket::type() const
 {
     return FC_TYPE( EXTRACT_LE_16BITS( &_wlanhdr->frame_control ) );
 }
 
 
 int OWaveLanPacket::version() const
 {
     return FC_VERSION( EXTRACT_LE_16BITS( &_wlanhdr->frame_control ) );
 }
 
 
 bool OWaveLanPacket::fromDS() const
 {
     return FC_FROM_DS( EXTRACT_LE_16BITS( &_wlanhdr->frame_control ) );
 }
 
 
 bool OWaveLanPacket::toDS() const
 {
     return FC_TO_DS( EXTRACT_LE_16BITS( &_wlanhdr->frame_control ) );
 }
 
 
 bool OWaveLanPacket::usesPowerManagement() const
 {
     return FC_POWER_MGMT( EXTRACT_LE_16BITS( &_wlanhdr->frame_control ) );
 }
 
 
 bool OWaveLanPacket::usesWep() const
 {
     return FC_WEP( EXTRACT_LE_16BITS( &_wlanhdr->frame_control ) );
 }
 
 
 /*======================================================================================
  * OWaveLanManagementPacket
  *======================================================================================*/
 
 OWaveLanManagementPacket::OWaveLanManagementPacket( const unsigned char* end, const struct ieee_802_11_mgmt_header* data, OWaveLanPacket* parent )
                 :QObject( parent, "802.11 Management" ), _header( data ),
                 _body( (const struct ieee_802_11_mgmt_body*) (data+1) )
 {
     qDebug( "OWaveLanManagementPacket::OWaveLanManagementPacket(): decoding frame..." );
     qDebug( "Detected subtype is '%s'", (const char*) managementType() );
 
     // grab tagged values
     const unsigned char* ptr = (const unsigned char*) (_body+1);
     while (ptr < end)
     {
         switch ( *ptr )
         {
             case E_SSID: new OWaveLanManagementSSID( end, (struct ssid_t*) ptr, this ); break;
             case E_FH: new OWaveLanManagementFH( end, (struct fh_t*) ptr, this ); break;
             case E_DS: new OWaveLanManagementDS( end, (struct ds_t*) ptr, this ); break;
             case E_RATES: new OWaveLanManagementRates( end, (struct rates_t*) ptr, this ); break;
             case E_CF: new OWaveLanManagementCF( end, (struct cf_t*) ptr, this ); break;
             case E_TIM: new OWaveLanManagementTim( end, (struct tim_t*) ptr, this ); break;
             case E_IBSS: new OWaveLanManagementIBSS( end, (struct ibss_t*) ptr, this ); break;
             case E_CHALLENGE: new OWaveLanManagementChallenge( end, (struct challenge_t*) ptr, this ); break;
         }
         ptr+= ( ( struct ssid_t* ) ptr )->length; // skip length of tagged value
         ptr+= 2; // skip tag ID and length
     }
 }
 
 
 OWaveLanManagementPacket::~OWaveLanManagementPacket()
 {
 }
 
 
 QString OWaveLanManagementPacket::managementType() const
 {
     switch ( FC_SUBTYPE( EXTRACT_LE_16BITS( &_header->fc ) ) )
     {
         case ST_ASSOC_REQUEST: return "AssociationRequest"; break;
         case ST_ASSOC_RESPONSE: return "AssociationResponse"; break;
         case ST_REASSOC_REQUEST: return "ReassociationRequest"; break;
         case ST_REASSOC_RESPONSE: return "ReassociationResponse"; break;
         case ST_PROBE_REQUEST: return "ProbeRequest"; break;
         case ST_PROBE_RESPONSE: return "ProbeResponse"; break;
         case ST_BEACON: return "Beacon"; break;
         case ST_ATIM: return "Atim"; break;
         case ST_DISASSOC: return "Disassociation"; break;
         case ST_AUTH: return "Authentication"; break;
         case ST_DEAUTH: return "Deathentication"; break;
         default:
             qWarning( "OWaveLanManagementPacket::managementType(): unhandled subtype %d", FC_SUBTYPE( EXTRACT_LE_16BITS( &_header->fc ) ) );
             return "Unknown";
     }
 }
 
 
 int OWaveLanManagementPacket::beaconInterval() const
 {
     return EXTRACT_LE_16BITS( &_body->beacon_interval );
 }
 
 
 int OWaveLanManagementPacket::capabilities() const
 {
     return EXTRACT_LE_16BITS( &_body->capability_info );
 }
 
 
 bool OWaveLanManagementPacket::canESS() const
 {
     return CAPABILITY_ESS( EXTRACT_LE_16BITS( &_body->capability_info ) );
 }
 
 
 bool OWaveLanManagementPacket::canIBSS() const
 {
     return CAPABILITY_IBSS( EXTRACT_LE_16BITS( &_body->capability_info ) );
 }
 
 
 bool OWaveLanManagementPacket::canCFP() const
 {
     return CAPABILITY_CFP( EXTRACT_LE_16BITS( &_body->capability_info ) );
 }
 
 
 bool OWaveLanManagementPacket::canCFP_REQ() const
 {
     return CAPABILITY_CFP_REQ( EXTRACT_LE_16BITS( &_body->capability_info ) );
 }
 
 
 bool OWaveLanManagementPacket::canPrivacy() const
 {
     return CAPABILITY_PRIVACY( EXTRACT_LE_16BITS( &_body->capability_info ) );
 }
 
 
 /*======================================================================================
  * OWaveLanManagementSSID
  *======================================================================================*/
 
 OWaveLanManagementSSID::OWaveLanManagementSSID( const unsigned char* end, const struct ssid_t* data, QObject* parent )
                 :QObject( parent, "802.11 SSID" ), _data( data )
 {
     qDebug( "OWaveLanManagementSSID()" );
 }
 
 
 OWaveLanManagementSSID::~OWaveLanManagementSSID()
 {
 }
 
 
 QString OWaveLanManagementSSID::ID() const
 {
     int length = _data->length;
     if ( length > 32 ) length = 32;
     char essid[length+1];
     memcpy( &essid, &_data->ssid, length );
     essid[length] = 0x0;
     return essid;
 }
 
 
 /*======================================================================================
  * OWaveLanManagementRates
  *======================================================================================*/
 
 OWaveLanManagementRates::OWaveLanManagementRates( const unsigned char* end, const struct rates_t* data, QObject* parent )
                 :QObject( parent, "802.11 Rates" ), _data( data )
 {
     qDebug( "OWaveLanManagementRates()" );
 }
 
 
 OWaveLanManagementRates::~OWaveLanManagementRates()
 {
 }
 
 /*======================================================================================
  * OWaveLanManagementCF
  *======================================================================================*/
 
 OWaveLanManagementCF::OWaveLanManagementCF( const unsigned char* end, const struct cf_t* data, QObject* parent )
                 :QObject( parent, "802.11 CF" ), _data( data )
 {
     qDebug( "OWaveLanManagementCF()" );
 }
 
 
 OWaveLanManagementCF::~OWaveLanManagementCF()
 {
 }
 
 /*======================================================================================
  * OWaveLanManagementFH
  *======================================================================================*/
 
 OWaveLanManagementFH::OWaveLanManagementFH( const unsigned char* end, const struct fh_t* data, QObject* parent )
                 :QObject( parent, "802.11 FH" ), _data( data )
 {
     qDebug( "OWaveLanManagementFH()" );
 }
 
 
 OWaveLanManagementFH::~OWaveLanManagementFH()
 {
 }
 
 /*======================================================================================
  * OWaveLanManagementDS
  *======================================================================================*/
 
 OWaveLanManagementDS::OWaveLanManagementDS( const unsigned char* end, const struct ds_t* data, QObject* parent )
                 :QObject( parent, "802.11 DS" ), _data( data )
 {
     qDebug( "OWaveLanManagementDS()" );
 }
 
 
 OWaveLanManagementDS::~OWaveLanManagementDS()
 {
 }
 
 
 int OWaveLanManagementDS::channel() const
 {
     return _data->channel;
 }
 
 /*======================================================================================
  * OWaveLanManagementTim
  *======================================================================================*/
 
 OWaveLanManagementTim::OWaveLanManagementTim( const unsigned char* end, const struct tim_t* data, QObject* parent )
                 :QObject( parent, "802.11 Tim" ), _data( data )
 {
     qDebug( "OWaveLanManagementTim()" );
 }
 
 
 OWaveLanManagementTim::~OWaveLanManagementTim()
 {
 }
 
 /*======================================================================================
  * OWaveLanManagementIBSS
  *======================================================================================*/
 
 OWaveLanManagementIBSS::OWaveLanManagementIBSS( const unsigned char* end, const struct ibss_t* data, QObject* parent )
                 :QObject( parent, "802.11 IBSS" ), _data( data )
 {
     qDebug( "OWaveLanManagementIBSS()" );
 }
 
 
 OWaveLanManagementIBSS::~OWaveLanManagementIBSS()
 {
 }
 
 /*======================================================================================
  * OWaveLanManagementChallenge
  *======================================================================================*/
 
 OWaveLanManagementChallenge::OWaveLanManagementChallenge( const unsigned char* end, const struct challenge_t* data, QObject* parent )
                 :QObject( parent, "802.11 Challenge" ), _data( data )
 {
     qDebug( "OWaveLanManagementChallenge()" );
 }
 
 
 OWaveLanManagementChallenge::~OWaveLanManagementChallenge()
 {
 }
 
 /*======================================================================================
  * OWaveLanDataPacket
  *======================================================================================*/
 
 OWaveLanDataPacket::OWaveLanDataPacket( const unsigned char* end, const struct ieee_802_11_data_header* data, OWaveLanPacket* parent )
                 :QObject( parent, "802.11 Data" ), _header( data )
 {
     qDebug( "OWaveLanDataPacket::OWaveLanDataPacket(): decoding frame..." );
 
     const unsigned char* payload = (const unsigned char*) data + sizeof( struct ieee_802_11_data_header );
 
     #warning The next line works for most cases, but can not be correct generally!
     if (!( ( (OWaveLanPacket*) this->parent())->duration() )) payload -= 6; // compensation for missing last address
 
     new OLLCPacket( end, (const struct ieee_802_11_802_2_header*) payload, this );
 }
 
 
 OWaveLanDataPacket::~OWaveLanDataPacket()
 {
 }
 
 
 /*======================================================================================
  * OLLCPacket
  *======================================================================================*/
 
 OLLCPacket::OLLCPacket( const unsigned char* end, const struct ieee_802_11_802_2_header* data, QObject* parent )
                 :QObject( parent, "802.11 LLC" ), _header( data )
 {
     qDebug( "OLLCPacket::OLLCPacket(): decoding frame..." );
 
     if ( !(_header->oui[0] || _header->oui[1] || _header->oui[2]) )
     {
         qDebug( "OLLCPacket::OLLCPacket(): contains an encapsulated Ethernet frame (type=%04X)", EXTRACT_16BITS( &_header->type ) );
 
         switch ( EXTRACT_16BITS( &_header->type ) ) // defined in linux/if_ether.h
         {
             case ETH_P_IP: new OIPPacket( end, (const struct iphdr*) (data+1), this ); break;
             default: qDebug( "OLLCPacket::OLLCPacket(): Unknown Encapsulation Type" );
         }
 
     }
 }
 
 
 OLLCPacket::~OLLCPacket()
 {
 }
 
 
 /*======================================================================================
  * OWaveLanControlPacket
  *======================================================================================*/
 
 OWaveLanControlPacket::OWaveLanControlPacket( const unsigned char* end, const struct ieee_802_11_control_header* data, OWaveLanPacket* parent )
                 :QObject( parent, "802.11 Data" ), _header( data )
 {
     qDebug( "OWaveLanControlPacket::OWaveLanDataControl(): decoding frame..." );
     //TODO: Implement this
 }
 
 
 OWaveLanControlPacket::~OWaveLanControlPacket()
 {
 }
 
 
 /*======================================================================================
  * OPacketCapturer
  *======================================================================================*/
 
 OPacketCapturer::OPacketCapturer( QObject* parent, const char* name )
                  :QObject( parent, name ), _name( QString::null ), _open( false ),
                  _pch( 0 ), _pcd( 0 ), _sn( 0 )
 {
 }
 
 
 OPacketCapturer::~OPacketCapturer()
 {
     if ( _open )
     {
         qDebug( "OPacketCapturer::~OPacketCapturer(): pcap still open, autoclosing." );
         close();
     }
 }
 
 
 void OPacketCapturer::setBlocking( bool b )
 {
     if ( pcap_setnonblock( _pch, 1-b, _errbuf ) != -1 )
     {
         qDebug( "OPacketCapturer::setBlocking(): blocking mode changed successfully." );
     }
     else
     {
         qDebug( "OPacketCapturer::setBlocking(): can't change blocking mode: %s", _errbuf );
     }
 }
 
 
 bool OPacketCapturer::blocking() const
 {
     int b = pcap_getnonblock( _pch, _errbuf );
     if ( b == -1 )
     {
         qDebug( "OPacketCapturer::blocking(): can't get blocking mode: %s", _errbuf );
         return -1;
     }
     return !b;
 }
 
 
 void OPacketCapturer::close()
 {
     if ( _open )
     {
         if ( _sn )
         {
             _sn->disconnect( SIGNAL( activated(int) ), this, SLOT( readyToReceive() ) );
             delete _sn;
         }
         if ( _pcd )
         {
             pcap_dump_close( _pcd );
             _pcd = 0;
         }
         pcap_close( _pch );
         _open = false;
     }
 
     qDebug( "OPacketCapturer::close() --- dumping capturing statistics..." );
     qDebug( "--------------------------------------------------" );
     for( QMap<QString,int>::Iterator it = _stats.begin(); it != _stats.end(); ++it )
         qDebug( "%s : %d", (const char*) it.key(), it.data() );
     qDebug( "--------------------------------------------------" );
 
 }
 
 
 int OPacketCapturer::dataLink() const
 {
     return pcap_datalink( _pch );
 }
 
 
 int OPacketCapturer::fileno() const
 {
     if ( _open )
     {
         return pcap_fileno( _pch );
     }
     else
     {
         return -1;
     }
 }
 
 OPacket* OPacketCapturer::next()
 {
     packetheaderstruct header;
     qDebug( "==> OPacketCapturer::next()" );
     const unsigned char* pdata = pcap_next( _pch, &header );
     qDebug( "<== OPacketCapturer::next()" );
     if ( _pcd )
         pcap_dump( (u_char*) _pcd, &header, pdata );
 
-    if ( header.len )
+    if ( pdata && header.len )
     {
         OPacket* p = new OPacket( dataLink(), header, pdata, 0 );
         // packets shouldn't be inserted in the QObject child-parent hierarchy,
         // because due to memory constraints they will be deleted as soon
         // as possible - that is right after they have been processed
         // by emit() [ see below ]
         //TODO: make gathering statistics optional, because it takes time
         p->updateStats( _stats, const_cast<QObjectList*>( p->children() ) );
 
         return p;
     }
     else
     {
+        qWarning( "OPacketCapturer::next() - no packet received!" );
         return 0;
     }
 }
 
 
 bool OPacketCapturer::open( const QString& name, const QString& filename )
 {
     if ( _open )
     {
         if ( name == _name )    // ignore opening an already openend device
         {
             return true;
         }
         else                    // close the last opened device
         {
             close();
         }
     }
 
     _name = name;
 
     // open libpcap
     pcap_t* handle = pcap_open_live( const_cast<char*>( (const char*) name ), 1024, 0, 0, &_errbuf[0] );
 
     if ( !handle )
     {
         qWarning( "OPacketCapturer::open(): can't open libpcap with '%s': %s", (const char*) name, _errbuf );
         return false;
     }
 
     qDebug( "OPacketCapturer::open(): libpcap [%s] opened successfully.", (const char*) name );
     _pch = handle;
     _open = true;
     _stats.clear();
 
     // in case we have an application object, create a socket notifier
     if ( qApp ) //TODO: I don't like this here...
     {
         _sn = new QSocketNotifier( fileno(), QSocketNotifier::Read );
         connect( _sn, SIGNAL( activated(int) ), this, SLOT( readyToReceive() ) );
     }
 
     // if requested, open a dump
     pcap_dumper_t* dump = pcap_dump_open( _pch, const_cast<char*>( (const char*) filename ) );
     if ( !dump )
     {
         qWarning( "OPacketCapturer::open(): can't open dump with '%s': %s", (const char*) filename, _errbuf );
         return false;
     }
     qDebug( "OPacketCapturer::open(): dump [%s] opened successfully.", (const char*) filename );
     _pcd = dump;
 
     return true;
 }
 
 
 bool OPacketCapturer::open( const QFile& file )
 {
     QString name = file.name();
 
     if ( _open )
     {
         close();
         if ( name == _name )    // ignore opening an already openend device
         {
             return true;
         }
         else                    // close the last opened device
         {
             close();
         }
     }
 
     _name = name;
 
     pcap_t* handle = pcap_open_offline( const_cast<char*>( (const char*) name ), &_errbuf[0] );
 
     if ( handle )
     {
         qDebug( "OPacketCapturer::open(): libpcap opened successfully." );
         _pch = handle;
         _open = true;
 
         // in case we have an application object, create a socket notifier
         if ( qApp )
         {
             _sn = new QSocketNotifier( fileno(), QSocketNotifier::Read );
             connect( _sn, SIGNAL( activated(int) ), this, SLOT( readyToReceive() ) );
         }
 
         return true;
     }
     else
     {
         qDebug( "OPacketCapturer::open(): can't open libpcap with '%s': %s", (const char*) name, _errbuf );
         return false;
     }
 
 }
 
 
 bool OPacketCapturer::isOpen() const
 {
     return _open;
 }
 
 
 void OPacketCapturer::readyToReceive()
 {
     qDebug( "OPacketCapturer::readyToReceive(): about to emit 'receivePacket(p)'" );
     OPacket* p = next();
     emit receivedPacket( p );
     // emit is synchronous - packet has been dealt with, now it's safe to delete
     delete p;
 }
 
 
 const QMap<QString,int>& OPacketCapturer::statistics() const
 {
     return _stats;
 }