Although not yet complete, the DHCP decoding is now usable

2 files changed, 92 insertions, 0 deletions

diff --git a/libopie2/opienet/opcap.cpp b/libopie2/opienet/opcap.cpp
index f1f2b4b..7a6f61b 100644
--- a/libopie2/opienet/opcap.cpp
+++ b/libopie2/opienet/opcap.cpp
@@ -364,104 +364,186 @@ OUDPPacket::OUDPPacket( const unsigned char* end, const struct udphdr* data, QOb
     if ( fromPort() == UDP_PORT_BOOTPS || fromPort() == UDP_PORT_BOOTPC ||
          toPort() == UDP_PORT_BOOTPS || toPort() == UDP_PORT_BOOTPC )
     {
         qDebug( "seems to be part of a DHCP conversation => creating DHCP packet." );
         new ODHCPPacket( end, (const struct dhcp_packet*) (data+1), this );
     }
 }
 
 
 OUDPPacket::~OUDPPacket()
 {
 }
 
 
 int OUDPPacket::fromPort() const
 {
     return EXTRACT_16BITS( &_udphdr->source );
 }
 
 
 int OUDPPacket::toPort() const
 {
     return EXTRACT_16BITS( &_udphdr->dest );
 }
 
 
 int OUDPPacket::length() const
 {
     return EXTRACT_16BITS( &_udphdr->len );
 }
 
 
 int OUDPPacket::checksum() const
 {
     return EXTRACT_16BITS( &_udphdr->check );
 }
 
 
 /*======================================================================================
  * ODHCPPacket
  *======================================================================================*/
 
 
 ODHCPPacket::ODHCPPacket( const unsigned char* end, const struct dhcp_packet* data, QObject* parent )
            :QObject( parent, "DHCP" ), _dhcphdr( data )
 
 {
     qDebug( "ODHCPPacket::ODHCPPacket(): decoding DHCP information..." );
+    qDebug( "DHCP opcode seems to be %02d - '%s'", _dhcphdr->op, isRequest() ? "REQUEST" : "REPLY" );
+    qDebug( "clientAddress: %s", (const char*) clientAddress().toString() );
+    qDebug( "  yourAddress: %s", (const char*) yourAddress().toString() );
+    qDebug( "serverAddress: %s", (const char*) serverAddress().toString() );
+    qDebug( " relayAddress: %s", (const char*) relayAddress().toString() );
+    qDebug( "parsing DHCP options..." );
+
+    _type = 0;
+
+    const unsigned char* option = &_dhcphdr->options[4];
+    char tag = -1;
+    char len = -1;
+
+    while ( ( tag = *option++ ) != -1 /* end of option field */ )
+    {
+        len = *option++;
+        qDebug( "recognized DHCP option #%d, length %d", tag, len );
+
+        if ( tag == DHO_DHCP_MESSAGE_TYPE )
+            _type = *option;
+
+        option += len;
+        if ( option >= end )
+        {
+            qWarning( "DHCP parsing ERROR: sanity check says the packet is at its end!" );
+            break;
+        }
+    }
+
+    qDebug( "DHCP type seems to be '%s'", (const char*) type() );
 }
 
 
 ODHCPPacket::~ODHCPPacket()
 {
 }
 
 
+bool ODHCPPacket::isRequest() const
+{
+    return ( _dhcphdr->op == 01 );
+}
+
+
+bool ODHCPPacket::isReply() const
+{
+    return ( _dhcphdr->op == 02 );
+}
+
+
+QString ODHCPPacket::type() const
+{
+    switch ( _type )
+    {
+        case 1: return "DISCOVER";
+        case 2: return "OFFER";
+        case 3: return "REQUEST";
+        case 4: return "DECLINE";
+        case 5: return "ACK";
+        case 6: return "NAK";
+        case 7: return "RELEASE";
+        case 8: return "INFORM";
+        default: qWarning( "ODHCPPacket::type(): invalid DHCP type (%d) !", _dhcphdr->op ); return "<unknown>";
+    }
+}
+
+
+QHostAddress ODHCPPacket::clientAddress() const
+{
+    return EXTRACT_32BITS( &_dhcphdr->ciaddr );
+}
+
+
+QHostAddress ODHCPPacket::yourAddress() const
+{
+    return EXTRACT_32BITS( &_dhcphdr->yiaddr );
+}
+
+
+QHostAddress ODHCPPacket::serverAddress() const
+{
+    return EXTRACT_32BITS( &_dhcphdr->siaddr );
+}
+
+
+QHostAddress ODHCPPacket::relayAddress() const
+{
+    return EXTRACT_32BITS( &_dhcphdr->giaddr );
+}
+
 /*======================================================================================
  * 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()
 {
 }
 
 
 int OTCPPacket::fromPort() const
 {
     return EXTRACT_16BITS( &_tcphdr->source );
 }
 
 
 int OTCPPacket::toPort() const
 {
     return EXTRACT_16BITS( &_tcphdr->dest );
 }
 
 
 int OTCPPacket::seq() const
 {
     return EXTRACT_16BITS( &_tcphdr->seq );
 }
 
 
 int OTCPPacket::ack() const
 {
     return EXTRACT_16BITS( &_tcphdr->ack_seq );
 }
 
 
 int OTCPPacket::window() const
 {
     return EXTRACT_16BITS( &_tcphdr->window );
 }
 
 
diff --git a/libopie2/opienet/opcap.h b/libopie2/opienet/opcap.h
index 0c9e7da..a031dd1 100644
--- a/libopie2/opienet/opcap.h
+++ b/libopie2/opienet/opcap.h
@@ -454,98 +454,108 @@ class OARPPacket : public QObject
     OARPPacket( const unsigned char*, const struct myarphdr*, QObject* parent = 0 );
     virtual ~OARPPacket();
 
     QHostAddress senderIPV4Address() const;
     OMacAddress senderMacAddress() const;
     QHostAddress targetIPV4Address() const;
     OMacAddress targetMacAddress() const;
 
     //int type() const;
     QString type() const;
 
   private:
     const struct myarphdr* _arphdr;
 };
 
 /*======================================================================================
  * OUDPPacket
  *======================================================================================*/
 
 class OUDPPacket : public QObject
 {
   Q_OBJECT
 
   public:
     OUDPPacket( const unsigned char*, const struct udphdr*, QObject* parent = 0 );
     virtual ~OUDPPacket();
 
     int fromPort() const;
     int toPort() const;
     int length() const;
     int checksum() const;
 
   private:
     const struct udphdr* _udphdr;
 };
 
 /*======================================================================================
  * ODHCPPacket
  *======================================================================================*/
 
 class ODHCPPacket : public QObject
 {
   Q_OBJECT
 
   public:
     ODHCPPacket( const unsigned char*, const struct dhcp_packet*, QObject* parent = 0 );
     virtual ~ODHCPPacket();
 
+    QHostAddress clientAddress() const;
+    QHostAddress yourAddress() const;
+    QHostAddress serverAddress() const;
+    QHostAddress relayAddress() const;
+
+    bool isRequest() const;
+    bool isReply() const;
+    QString type() const;
+
   private:
     const struct dhcp_packet* _dhcphdr;
+    unsigned char _type;
 };
 
 /*======================================================================================
  * 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;
     int seq() const;
     int ack() const;
     int window() const;
     int checksum() 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.
  * @see http://tcpdump.org
  */
 class OPacketCapturer : public QObject
 {
   Q_OBJECT
 
   public:
     /**
      * Constructor.
      */
     OPacketCapturer( QObject* parent = 0, const char* name = 0 );
     /**
      * Destructor.