The following will give you a simplified overview of Wireshark’s function blocks:
Figure 7.1. Wireshark function blocks
The function blocks in more detail:
Handling of all user input/output (all windows, dialogs and such).
Source code can be found in the ui/qt directory.
Main "glue code" that holds the other blocks together. Source
code can be found in the root directory.
Enhanced Packet ANalyzer — the packet analyzing engine.
Source code can be found in the epan directory. Epan provides
the following APIs:
Protocol Tree. Dissection information for an individual packet.
Dissectors. The various protocol dissectors in
Dissector Plugins - Support for implementing dissectors as separate modules.
Source code can be found in plugins.
Display Filters - The display filter engine at
The wiretap library is used to read and write capture files in libpcap,
pcapng, and many other file formats. Source code is in the
The interface to the capture engine. Source code is in the
The capture engine itself. This is the only part that executes with
elevated privileges. Source code is in the root directory.
- Npcap and libpcap
These are external libraries that provide packet capture
and filtering support on different platforms. The filtering in Npcap and libpcap
works at a much lower level than Wireshark’s display filters and uses a
significantly different mechanism. That’s why there are different display and
capture filter syntaxes.