The following will give you a simplified overview of Wireshark's function blocks:
The function blocks in more detail:
- GTK 1/2
Handling of all user input/output (all windows, dialogs and such). Source code can be found in the
gtkdirectory.- Core
Main "glue code" that holds the other blocks together. Source code can be found in the root directory.
- Epan
Ethereal Packet ANalyzer (XXX - is this correct?) the packet analyzing engine. Source code can be found in the
epandirectory.Protocol-Tree - Keep data of the capture file protocol information.
Dissectors - The various protocol dissectors in
epan/dissectors.Plugins - Some of the protocol dissectors are implemented as plugins. Source code can be found at
plugins.Display-Filters - the display filter engine at
epan/dfilter.
- Capture
Capture engine.
- Wiretap
The wiretap library is used to read/write capture files in libpcap and a lot of other file formats. Source code in the
wiretapdirectory.- Win-/libpcap (not part of the Wireshark package)
The platform dependent packet capture library, including the capture filter engine. That's the reason why we still have different display and capture filter syntax, as two different filtering engines are used.