add parsing of ARP packets

3 files changed, 110 insertions, 26 deletions

diff --git a/libopie2/opienet/802_11_user.h b/libopie2/opienet/802_11_user.h
index cd98503..ad84514 100644
--- a/libopie2/opienet/802_11_user.h
+++ b/libopie2/opienet/802_11_user.h
@@ -55,27 +55,6 @@ struct ieee_802_3_header {
 
 #define P80211_OUI_LEN 3
 
-struct ieee_802_11_snap_header {
-
-        u_int8_t    dsap;   /* always 0xAA */
-        u_int8_t    ssap;   /* always 0xAA */
-        u_int8_t    ctrl;   /* always 0x03 */
-        u_int8_t    oui[P80211_OUI_LEN];    /* organizational universal id */
-
-} __attribute__ ((packed));
-
-#define P80211_LLC_OUI_LEN 3
-
-struct ieee_802_11_802_1H_header {
-
-        u_int8_t    dsap;
-        u_int8_t    ssap;   /* always 0xAA */
-        u_int8_t    ctrl;   /* always 0x03 */
-        u_int8_t    oui[P80211_OUI_LEN];    /* organizational universal id */
-        u_int16_t    unknown1;      /* packet type ID fields */
-                u_int16_t    unknown2;  /* here is something like length in some cases */
-} __attribute__ ((packed));
-
 struct ieee_802_11_802_2_header {
 
         u_int8_t    dsap;
@@ -83,9 +62,31 @@ struct ieee_802_11_802_2_header {
         u_int8_t    ctrl;   /* always 0x03 */
         u_int8_t    oui[P80211_OUI_LEN];    /* organizational universal id */
         u_int16_t   type;      /* packet type ID field */
+};
 
-} __attribute__ ((packed));
-
+/* See RFC 826 for protocol description.  ARP packets are variable
+   in size; the arphdr structure defines the fixed-length portion.
+   Protocol type values are the same as those for 10 Mb/s Ethernet.
+   It is followed by the variable-sized fields ar_sha, arp_spa,
+   arp_tha and arp_tpa in that order, according to the lengths
+   specified.  Field names used correspond to RFC 826.  */
+
+#define ETH_ALEN 6
+
+struct myarphdr
+{
+    unsigned short int ar_hrd;          /* Format of hardware address.  */
+    unsigned short int ar_pro;          /* Format of protocol address.  */
+    unsigned char ar_hln;               /* Length of hardware address.  */
+    unsigned char ar_pln;               /* Length of protocol address.  */
+    unsigned short int ar_op;           /* ARP opcode (command).  */
+    /* Ethernet looks like this : This bit is variable sized
+       however...  */
+    unsigned char ar_sha[ETH_ALEN];   /* Sender hardware address.  */
+    unsigned char ar_sip[4];          /* Sender IP address.  */
+    unsigned char ar_tha[ETH_ALEN];   /* Target hardware address.  */
+    unsigned char ar_tip[4];          /* Target IP address.  */
+};
 
 
 // following is incoplete and may be incorrect and need reorganization
diff --git a/libopie2/opienet/opcap.cpp b/libopie2/opienet/opcap.cpp
index 675818e..e2ab6d7 100644
--- a/libopie2/opienet/opcap.cpp
+++ b/libopie2/opienet/opcap.cpp
@@ -158,7 +158,6 @@ int OPacket::len() const
 
 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() );
@@ -209,7 +208,6 @@ int OEthernetPacket::type() const
 
 OIPPacket::OIPPacket( const unsigned char* end, const struct iphdr* data, QObject* parent )
           :QObject( parent, "IP" ), _iphdr( data )
-
 {
     qDebug( "OIPPacket::OIPPacket(): decoding IP header..." );
 
@@ -287,6 +285,66 @@ int OIPPacket::checksum() const
 }
 
 /*======================================================================================
+ * OARPPacket
+ *======================================================================================*/
+
+
+OARPPacket::OARPPacket( const unsigned char* end, const struct myarphdr* data, QObject* parent )
+           :QObject( parent, "ARP" ), _arphdr( data )
+{
+    qDebug( "OARPPacket::OARPPacket(): decoding ARP header..." );
+    qDebug( "ARP type seems to be %02d - '%s'", EXTRACT_16BITS( &_arphdr->ar_op ), (const char*) type() );
+    qDebug( "Sender: MAC %s = IP %s", (const char*) senderMacAddress().toString(), (const char*) senderIPV4Address().toString() );
+    qDebug( "Target: MAC %s = IP %s", (const char*) targetMacAddress().toString(), (const char*) targetIPV4Address().toString() );
+}
+
+
+OARPPacket::~OARPPacket()
+{
+}
+
+
+QString OARPPacket::type() const
+{
+    switch ( EXTRACT_16BITS( &_arphdr->ar_op ) )
+    {
+        case 1: return "REQUEST";
+        case 2: return "REPLY";
+        case 3: return "RREQUEST";
+        case 4: return "RREPLY";
+        case 8: return "InREQUEST";
+        case 9: return "InREPLY";
+        case 10: return "NAK";
+        default: qWarning( "OARPPacket::type(): invalid ARP type!" ); return "<unknown>";
+    }
+}
+
+
+QHostAddress OARPPacket::senderIPV4Address() const
+{
+    return EXTRACT_32BITS( &_arphdr->ar_sip );
+}
+
+
+QHostAddress OARPPacket::targetIPV4Address() const
+{
+    return EXTRACT_32BITS( &_arphdr->ar_tip );
+}
+
+
+OMacAddress OARPPacket::senderMacAddress() const
+{
+    return OMacAddress( _arphdr->ar_sha );
+}
+
+
+OMacAddress OARPPacket::targetMacAddress() const
+{
+    return OMacAddress( _arphdr->ar_tha );
+}
+
+
+/*======================================================================================
  * OUDPPacket
  *======================================================================================*/
 
@@ -730,7 +788,8 @@ OLLCPacket::OLLCPacket( const unsigned char* end, const struct ieee_802_11_802_2
         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" );
+            case ETH_P_ARP: new OARPPacket( end, (const struct myarphdr*) (data+1), this ); break;
+            default: qWarning( "OLLCPacket::OLLCPacket(): Unknown Encapsulation (type=%04X)", EXTRACT_16BITS( &_header->type ) );
         }
 
     }
diff --git a/libopie2/opienet/opcap.h b/libopie2/opienet/opcap.h
index bee0ca0..5a50d9b 100644
--- a/libopie2/opienet/opcap.h
+++ b/libopie2/opienet/opcap.h
@@ -438,6 +438,30 @@ class OIPPacket : public QObject
 };
 
 /*======================================================================================
+ * OARPPacket
+ *======================================================================================*/
+
+class OARPPacket : public QObject
+{
+  Q_OBJECT
+
+  public:
+    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
  *======================================================================================*/