Chapter 9: Developing Ethereal

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Introduction

The fact that Ethereal is open source and distributed under the General Public License (GPL) allows many individuals to contribute to the overall success of the project. With developers throughout the world contributing for several years, Ethereal has become a viable tool for many organizations.

Ethereal developers have contributed new functionalities as well as features to the growing number of tools included in the Ethereal distribution. This includes the console-based version of Ethereal named Tethereal, as well as a number of other tools that are part of the Ethereal distribution.

The main Ethereal application is a Graphical User Interface (GUI) application utilizing components of GNU’s Not UNIX (GNU) Image Manipulation Program called GIMP. The latest version of the GIMP Toolkit is now called GTK+. GTK+ is the official name of the toolkit but most developers refer to it as GTK. Although the name implies that GNU owns GTK, this is not the case. GTK is maintained as a separate entity at www.gtk.org. Ethereal uses the GTK library and functions for its GUI implementation. New features often require modifications to the GUI. This might include new menu items or modifications to existing menu selections. The core of the application includes the main window, menus, utility functions, etc.

The components of Ethereal that dissect packet structures are called protocol dissectors. These components are individual source code modules that instruct the main Ethereal application on how to dissect a specific type of protocol. The dissector can be complex or simple based on the protocol that is being dissected. Most of the contributions to the Ethereal project are either new dissectors or enhancements to existing ones.

By utilizing the concepts within this chapter, you should be able to grasp the basic steps to become a contributor to the Ethereal project. Many users and developers worldwide would benefit from your efforts and welcome anything you might want contribute.

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