| -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 @@ -69,5 +69,47 @@ 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 { @@ -96,5 +138,4 @@ class OPacket : public QObject *======================================================================================*/ -//FIXME same critic as above -zecke class OEthernetPacket : public QObject { @@ -117,5 +158,5 @@ class OEthernetPacket : public QObject * OWaveLanPacket - DLT_IEEE802_11 frame *======================================================================================*/ -//FIXME same + class OWaveLanPacket : public QObject { @@ -147,5 +188,5 @@ class OWaveLanPacket : public QObject * OWaveLanManagementPacket - type: management (T_MGMT) *======================================================================================*/ -//FIXME same as above -zecke + class OWaveLanManagementPacket : public QObject { @@ -176,5 +217,5 @@ class OWaveLanManagementPacket : public QObject * OWaveLanManagementSSID *======================================================================================*/ -//FIXME is QObject necessary? -zecke + class OWaveLanManagementSSID : public QObject { @@ -194,5 +235,5 @@ class OWaveLanManagementSSID : public QObject * OWaveLanManagementRates *======================================================================================*/ -// FIXME same as above -zecke + class OWaveLanManagementRates : public QObject { @@ -211,5 +252,4 @@ class OWaveLanManagementRates : public QObject *======================================================================================*/ -//FIXME same.... class OWaveLanManagementCF : public QObject { @@ -228,5 +268,4 @@ class OWaveLanManagementCF : public QObject *======================================================================================*/ -//FIXME same class OWaveLanManagementFH : public QObject { @@ -244,5 +283,5 @@ class OWaveLanManagementFH : public QObject * OWaveLanManagementDS *======================================================================================*/ -//FIXME same + class OWaveLanManagementDS : public QObject { @@ -263,5 +302,4 @@ class OWaveLanManagementDS : public QObject *======================================================================================*/ -//FIXME guess what? class OWaveLanManagementTim : public QObject { @@ -280,5 +318,4 @@ class OWaveLanManagementTim : public QObject *======================================================================================*/ -//FIXME same as above ( Qobject ) class OWaveLanManagementIBSS : public QObject { @@ -329,5 +366,5 @@ class OWaveLanDataPacket : public QObject * OWaveLanControlPacket - type: control (T_CTRL) *======================================================================================*/ -// Qobject needed? + class OWaveLanControlPacket : public QObject { @@ -346,5 +383,4 @@ class OWaveLanControlPacket : public QObject *======================================================================================*/ -// QObject needed? class OLLCPacket : public QObject { @@ -356,5 +392,4 @@ class OLLCPacket : public QObject private: - //FIXME how to get that header? const struct ieee_802_11_802_2_header* _header; }; @@ -364,5 +399,4 @@ class OLLCPacket : public QObject *======================================================================================*/ -// Qobject as baseclass? class OIPPacket : public QObject { @@ -391,5 +425,5 @@ class OIPPacket : public QObject * OUDPPacket *======================================================================================*/ -// QObject? + class OUDPPacket : public QObject { @@ -411,5 +445,4 @@ class OUDPPacket : public QObject *======================================================================================*/ -// Qobect needed? class OTCPPacket : public QObject { |