decouple dump files from live capture to shift control over 'what' is dumped to applications

2 files changed, 47 insertions, 14 deletions

diff --git a/libopie2/opienet/opcap.cpp b/libopie2/opienet/opcap.cpp
index bef9182..1de7124 100644
--- a/libopie2/opienet/opcap.cpp
+++ b/libopie2/opienet/opcap.cpp
@@ -819,208 +819,228 @@ 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::closeDumpFile()
+{
+    if ( _pcd )
+    {
+        pcap_dump_close( _pcd );
+        _pcd = 0;
+    }
+    pcap_close( _pch );
+}
+
+
 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 );
+        closeDumpFile();
         _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 );
 }
 
 
+void OPacketCapturer::dump( OPacket* p )
+{
+    if ( !_pcd )
+    {
+        qWarning( "OPacketCapturer::dump() - cannot dump without open capture file!" );
+        return;
+    }
+    pcap_dump( (u_char*) _pcd, &p->_hdr, p->_data );
+}
+
+
 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 ( 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 )
+bool OPacketCapturer::open( const QString& name )
 {
     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
+    return true;
+}
+
+
+bool OPacketCapturer::openDumpFile( const QString& filename )
+{
     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;
diff --git a/libopie2/opienet/opcap.h b/libopie2/opienet/opcap.h
index ad5b07c..9119972 100644
--- a/libopie2/opienet/opcap.h
+++ b/libopie2/opienet/opcap.h
@@ -70,96 +70,98 @@ class QSocketNotifier;
  *======================================================================================*/
 
 /** @brief A class representing a data frame on the wire.
  *
  * The whole family of the packet classes are used when capturing frames from a network.
  * Most standard network protocols in use share a common architecture, which mostly is
  * a packet header and then the packet payload. In layered architectures, each lower layer
  * encapsulates data from its upper layer - that is it
  * treats the data from its upper layer as payload and prepends an own header to the packet,
  * which - again - is treated as the payload for the layer below. The figure below is an
  * example for how such a data frame is composed out of packets, e.g. when sending a mail.
  *
  * <pre>
  *                                                       | User Data |     == Mail Data
  *                                         | SMTP Header | User Data |     == SMTP
  *                           | TCP Header  | SMTP Header | User Data |     == TCP
  *               | IP Header | TCP Header  | SMTP Header | User Data |     == IP
  *  | MAC Header | IP Header | TCP Header  | SMTP Header | User Data |     == MAC
  *
  * </pre>
  *
  * The example is trimmed for simplicity, because the MAC (Medium Access Control) layer
  * also contains a few more levels of encapsulation.
  * Since the type of the payload is more or less independent from the encapsulating protocol,
  * the header must be inspected before attempting to decode the payload. Hence, the
  * encapsulation level varies and can't be deduced without actually looking into the packets.
  *
  * For actually working with captured frames, it's useful to identify the packets via names and
  * insert them into a parent/child - relationship based on the encapsulation. This is why
  * all packet classes derive from QObject. The amount of overhead caused by the QObject is
  * not a problem in this case, because we're talking about a theoratical maximum of about
  * 10 packets per captured frame. We need to stuff them into a searchable list anyway and the
  * QObject also cares about destroying the sub-, (child-) packets.
  *
  * This enables us to perform a simple look for packets of a certain type:
  * @code
  * OPacketCapturer* pcap = new OPacketCapturer();
  * pcap->open( "eth0" );
  * OPacket* p = pcap->next();
  * OIPPacket* ip = (OIPPacket*) p->child( "IP" ); // returns 0, if no such child exists
  * odebug << "got ip packet from " << ip->fromIPAddress().toString() << " to " << ip->toIPAddress().toString() << oendl;
  *
  */
 
 class OPacket : public QObject
 {
   Q_OBJECT
 
+  friend class OPacketCapturer;
+
   public:
     OPacket( int datalink, packetheaderstruct, const unsigned char*, QObject* parent );
     virtual ~OPacket();
 
     timevalstruct timeval() const;
 
     int caplen() const;
     int len() const;
     QString dump( int = 32 ) const;
 
     void updateStats( QMap<QString,int>&, QObjectList* );
 
   private:
     const packetheaderstruct _hdr;  // pcap packet header
     const unsigned char* _data;     // pcap packet data
     const unsigned char* _end;      // end of pcap packet data
 };
 
 /*======================================================================================
  * OEthernetPacket - DLT_EN10MB frame
  *======================================================================================*/
 
 class OEthernetPacket : public QObject
 {
   Q_OBJECT
 
   public:
     OEthernetPacket( const unsigned char*, const struct ether_header*, QObject* parent = 0 );
     virtual ~OEthernetPacket();
 
     OMacAddress sourceAddress() const;
     OMacAddress destinationAddress() const;
     int type() const;
 
   private:
     const struct ether_header* _ether;
 };
 
 /*======================================================================================
  * OPrismHeaderPacket - DLT_PRISM_HEADER frame
  *======================================================================================*/
 
 class OPrismHeaderPacket : public QObject
 {
   Q_OBJECT
 
   public:
     OPrismHeaderPacket( const unsigned char*, const struct prism_hdr*, QObject* parent = 0 );
@@ -479,128 +481,139 @@ class OUDPPacket : public QObject
   private:
     const struct udphdr* _udphdr;
 };
 
 /*======================================================================================
  * OTCPPacket
  *======================================================================================*/
 
 class OTCPPacket : public QObject
 {
   Q_OBJECT
 
   public:
     OTCPPacket( const unsigned char*, const struct tcphdr*, QObject* parent = 0 );
     virtual ~OTCPPacket();
 
     int fromPort() const;
     int toPort() const;
 
   private:
     const struct tcphdr* _tcphdr;
 };
 
 
 /*======================================================================================
  * OPacketCapturer
  *======================================================================================*/
 
 /**
  * @brief A class based wrapper for network packet capturing.
  *
  * This class is the base of a high-level interface to the well known packet capturing
  * library libpcap. ...
  */
 class OPacketCapturer : public QObject
 {
   Q_OBJECT
 
   public:
     /**
      * Constructor.
      */
     OPacketCapturer( QObject* parent = 0, const char* name = 0 );
     /**
      * Destructor.
      */
     ~OPacketCapturer();
     /**
-     * Setting the packet capturer to use blocking IO calls can be useful when
+     * Set the packet capturer to use blocking or non-blocking IO. This can be useful when
      * not using the socket notifier, e.g. without an application object.
      */
     void setBlocking( bool );
     /**
      * @returns true if the packet capturer uses blocking IO calls.
      */
     bool blocking() const;
     /**
-     * Closes the packet capturer. This is automatically done in the destructor.
+     * Close the packet capturer. This is automatically done in the destructor.
      */
     void close();
     /**
+     * Close the output capture file.
+     */
+    void closeDumpFile();
+    /**
      * @returns the data link type.
      * @see <pcap.h> for possible values.
      */
     int dataLink() const;
     /**
+     * Dump a packet to the output capture file.
+     */
+    void dump( OPacket* );
+    /**
      * @returns the file descriptor of the packet capturer. This is only useful, if
      * not using the socket notifier, e.g. without an application object.
      */
     int fileno() const;
     /**
      * @returns the next @ref OPacket from the packet capturer.
      * @note If blocking mode is true then this call might block.
      */
     OPacket* next();
     /**
      * Open the packet capturer to capture packets in live-mode from @a interface.
-     * If a @a filename is given, all captured packets are output to a tcpdump-compatible capture file.
      */
-    bool open( const QString& interface, const QString& filename = QString::null );
+    bool open( const QString& interface );
     /**
      * Open the packet capturer to capture packets in offline-mode from @a file.
      */
     bool open( const QFile& file );
     /**
+     * Open a prerecorded tcpdump compatible capture file for use with @ref dump()
+     */
+    bool openDumpFile( const QString& filename );
+    /**
      * @returns true if the packet capturer is open
      */
     bool isOpen() const;
     /**
      * @returns the snapshot length of this packet capturer
      */
     int snapShot() const;
     /**
      * @returns true if the input capture file has a different byte-order
      * than the byte-order of the running system.
      */
     bool swapped() const;
     /**
      * @returns the libpcap version string used to write the input capture file.
      */
     QString version() const;
     /**
      * @returns the packet statistic database.
      * @see QMap
      */
     const QMap<QString,int>& statistics() const;
 
   signals:
     /**
      * This signal is emitted, when a packet has been received.
      */
     void receivedPacket( OPacket* );
 
   protected slots:
     void readyToReceive();
 
   protected:
     QString _name;                                  // devicename
     bool _open;                                     // check this before doing pcap calls
     pcap_t* _pch;                                   // pcap library handle
     pcap_dumper_t* _pcd;                            // pcap dumper handle
     QSocketNotifier* _sn;                           // socket notifier for main loop
     mutable char _errbuf[PCAP_ERRBUF_SIZE];         // holds error strings from libpcap
     QMap<QString, int> _stats;                      // statistics;
 };
 
 #endif // OPCAP_H