| -rw-r--r-- | libopie2/opienet/opcap.h | 67 |
1 files changed, 50 insertions, 17 deletions
diff --git a/libopie2/opienet/opcap.h b/libopie2/opienet/opcap.h index 6bf7416..fe88e68 100644 --- a/libopie2/opienet/opcap.h +++ b/libopie2/opienet/opcap.h @@ -68,7 +68,49 @@ class QSocketNotifier; /*====================================================================================== * OPacket - A frame on the wire *======================================================================================*/ -// FIXME how many OPackets do we've at a time? QObject seams to be a big for that usage + +/** @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 @@ -95,7 +137,6 @@ class OPacket : public QObject * OEthernetPacket - DLT_EN10MB frame *======================================================================================*/ -//FIXME same critic as above -zecke class OEthernetPacket : public QObject { Q_OBJECT @@ -116,7 +157,7 @@ class OEthernetPacket : public QObject /*====================================================================================== * OWaveLanPacket - DLT_IEEE802_11 frame *======================================================================================*/ -//FIXME same + class OWaveLanPacket : public QObject { Q_OBJECT @@ -146,7 +187,7 @@ class OWaveLanPacket : public QObject /*====================================================================================== * OWaveLanManagementPacket - type: management (T_MGMT) *======================================================================================*/ -//FIXME same as above -zecke + class OWaveLanManagementPacket : public QObject { Q_OBJECT @@ -175,7 +216,7 @@ class OWaveLanManagementPacket : public QObject /*====================================================================================== * OWaveLanManagementSSID *======================================================================================*/ -//FIXME is QObject necessary? -zecke + class OWaveLanManagementSSID : public QObject { Q_OBJECT @@ -193,7 +234,7 @@ class OWaveLanManagementSSID : public QObject /*====================================================================================== * OWaveLanManagementRates *======================================================================================*/ -// FIXME same as above -zecke + class OWaveLanManagementRates : public QObject { Q_OBJECT @@ -210,7 +251,6 @@ class OWaveLanManagementRates : public QObject * OWaveLanManagementCF *======================================================================================*/ -//FIXME same.... class OWaveLanManagementCF : public QObject { Q_OBJECT @@ -227,7 +267,6 @@ class OWaveLanManagementCF : public QObject * OWaveLanManagementFH *======================================================================================*/ -//FIXME same class OWaveLanManagementFH : public QObject { Q_OBJECT @@ -243,7 +282,7 @@ class OWaveLanManagementFH : public QObject /*====================================================================================== * OWaveLanManagementDS *======================================================================================*/ -//FIXME same + class OWaveLanManagementDS : public QObject { Q_OBJECT @@ -262,7 +301,6 @@ class OWaveLanManagementDS : public QObject * OWaveLanManagementTim *======================================================================================*/ -//FIXME guess what? class OWaveLanManagementTim : public QObject { Q_OBJECT @@ -279,7 +317,6 @@ class OWaveLanManagementTim : public QObject * OWaveLanManagementIBSS *======================================================================================*/ -//FIXME same as above ( Qobject ) class OWaveLanManagementIBSS : public QObject { Q_OBJECT @@ -328,7 +365,7 @@ class OWaveLanDataPacket : public QObject /*====================================================================================== * OWaveLanControlPacket - type: control (T_CTRL) *======================================================================================*/ -// Qobject needed? + class OWaveLanControlPacket : public QObject { Q_OBJECT @@ -345,7 +382,6 @@ class OWaveLanControlPacket : public QObject * OLLCPacket - IEEE 802.2 Link Level Control *======================================================================================*/ -// QObject needed? class OLLCPacket : public QObject { Q_OBJECT @@ -355,7 +391,6 @@ class OLLCPacket : public QObject virtual ~OLLCPacket(); private: - //FIXME how to get that header? const struct ieee_802_11_802_2_header* _header; }; @@ -363,7 +398,6 @@ class OLLCPacket : public QObject * OIPPacket *======================================================================================*/ -// Qobject as baseclass? class OIPPacket : public QObject { Q_OBJECT @@ -390,7 +424,7 @@ class OIPPacket : public QObject /*====================================================================================== * OUDPPacket *======================================================================================*/ -// QObject? + class OUDPPacket : public QObject { Q_OBJECT @@ -410,7 +444,6 @@ class OUDPPacket : public QObject * OTCPPacket *======================================================================================*/ -// Qobect needed? class OTCPPacket : public QObject { Q_OBJECT |