Introduction
Introduction
This chapter will provide you with information about Ethereal
development in general.
What is Ethereal?
Well, if you want to start Ethereal development, you might already
know what Ethereal is doing. If not, please have a look at the
Ethereal User's Guide,
which will provide a lot of general information about it.
Development and maintenance of Ethereal
Ethereal was initially developed by Gerald Combs. Ongoing development
and maintenance of Ethereal is handled by the Ethereal team, a loose
group of individuals who fix bugs and provide new functionality.
There have also been a large number of people who have contributed
protocol dissectors to Ethereal, and it is expected that this will
continue. You can find a list of the people who have contributed
code to Ethereal by checking the about dialog box of Ethereal, or have
a look at the page on the Ethereal
web site.
The
communication between the developers is usually done trough the developer
mailing list, which can be joined by anyone interested in the development
process. At the time writing of this document, more than 500 persons are
subscribed to this mailing list!
It is strongly recommended to join the developer mailing list, if you
are going to do any Ethereal development. See
about the different Ethereal
mailing lists available.
Programming language(s) used
Almost any part of Ethereal is implemented in plain ANSI C.
The typical task for a new Ethereal developer is to extend an existing,
or write a new dissector for a specific network protocol. As (almost) any
dissector is written in plain old ANSI C, a good knowledge about ANSI C
will be sufficient for Ethereal development in almost any case.
So unless you are going to change the development process of Ethereal
itself, you won't come in touch with any other programming language than
ANSI C (such as perl or python, which are used only in the Ethereal build
process).
Beside the usual tools for developing a program in C (compiler, make, ...),
the build process uses some additional helper tools (Perl, Python, Sed,
...), which are needed for the build process and in the case Ethereal
should be installed from the released source packages. If Ethereal is
installed from a binary package, none of these helper tools are needed on
the target system.
Open Source Software
Ethereal is an open source software project, and is released under
the GNU General Public Licence (GPL).
You can freely use Ethereal on any number of computers you like, without
worrying about license keys or fees or such. In addition, all source
code is freely available under the GPL. Because of that, it is very easy
for people to add new protocols to Ethereal, either as plugins, or built
into the source, and they often do!
You are welcome to
modify Ethereal to suit your own needs, and it would be appreciated
if you contribute your improvements back to the Ethereal team.
You gain three benefits by contributing your improvements back to the
community:
Other people who find your contributions useful will appreciate
them, and you will know that you have helped people in the
same way that the developers of Ethereal have helped people.
The developers of Ethereal might improve your changes even more,
as there's always room for improvements. Or they may implement some
advanced things on top of your code, which can be useful for yourself
too.
The maintainers and developers of Ethereal will maintain your
code as well, fixing it when API changes or other changes are
made, and generally keeping it in tune with what is happening
with Ethereal. So if Ethereal is updated (which is done often),
you can get a new Ethereal version from the website and your changes
will already be included without any effort for you.
The Ethereal source code and binary kits for some platforms are all
available on the download page of the Ethereal website:
&EtherealDownloadPage;.
Releases and distributions
The officially released files can be found at: . A new Ethereal version is released, after
significant changes compared to the last release were completed or a
serious security issue was encountered. The typical release schedule is
about every 4-8 weeks (although this may vary).
There are two kinds of distributions: binary and source, both have their
advantages and disadvantages.
Binary distributions
Binary distributions are usually easy to install (as simply starting
the appropriate file is usually the only thing to do). They are available
for the following systems:
Win32 (.exe file). The typical windows end user is used to get an setup
.exe file, which will install all the required things for him.
Debian (.deb file)
RedHat (.rpm file)
However, if you want to start developing with Ethereal, the binary
distributions won't be much helpful, as you need the source files, of
course.
For details about how to build these binary distributions yourself,
e.g. if you need a distribution for a special audience, see
.
Source code distributions
It's still common for unix developers to give the end user a source
tarball and let the user compile it on their target machine (configure,
make, make install). However, for different unix (linux) distributions
it's becoming more common to release binary packages (e.g. .deb or .rpm
files) these days.
You should use the released sources if you want to build Ethereal from
source on your platform for productive use. However, if you going to
develop changes to the Ethereal sources, it might be better to use the
latest SVN sources. For details about the different ways to get the
Ethereal source code see .
Before building Ethereal from a source distribution, make sure you have
all the tools and libraries required to build. The following chapters will
describe the required tools and libraries in detail.
Reporting problems and getting help
If you have problems, or need help with Ethereal, there are several
places that may be of interest to you (well, beside this guide of
course).
FAQ
The "Frequently Asked Questions" will list often asked questions and
the corresponding answers.
Read the FAQ!
Before sending any mail to the mailing lists below, be sure to read the
FAQ, as it will often answer the question(s) you might have. This will save
yourself and others a lot of time (keep in mind that a lot of people are
subscribed to the mailing lists).
You will find the FAQ inside Ethereal by clicking the menu item
Help/Contents and selecting the FAQ page in the upcoming dialog.
An online version is available at the ethereal website:
&EtherealFAQPage;. You might
prefer this online version, as it's typically more up to date and the HTML
format is easier to use.
Mailing Lists
There are several mailing lists of specific Ethereal topics available:
ethereal-announce
This mailing list will inform you about new program
releases, which usually appear about every 4-8 weeks.
ethereal-users
This list is for users of Ethereal. People post
questions about building and using Ethereal, others (hopefully)
provide answers.
ethereal-dev
This list is for Ethereal developers. People post questions about
the development of Ethereal, others (hopefully) provide answers.
If you want to start developing a protocol dissector, join this list.
ethereal-cvs
This list is for Ethereal developers. Everytime a change to the SVN
repository is checked in, a mail to this mailing list is generated.
If you want to be notified about all the changes to the SVN
repository, join this list. Details about the SVN repository can be
found in .
You can subscribe to each of these lists from the Ethereal web site:
&EtherealWebSite;. Simply
select the mailing lists link on the left hand
side of the site. The lists are archived at the Ethereal web site
as well.
Tip!
You can search in the list archives to see if someone asked the same
question some time before and maybe already got an answer. That way you
don't have to wait until someone answers your question.
Reporting Problems
Note!
Before reporting any problems, please make sure you have installed the
latest version of Ethereal.
If you report problems, provide as much
information as possible. In general, just think about what
you would need to find that problem, if someone else sends you such a
problem report. Also keep in mind, that people uses a lot of different
platforms to compile/run Ethereal on.
When reporting problems with Ethereal, it is helpful if you supply the
following information:
The version number of Ethereal and the dependent libraries linked with
it, eg GTK+, etc. You can obtain this with the command
ethereal -v.
Information about the platform you run Ethereal on.
A detailed description of your problem.
If you get an error/warning message, copy the text of that message (and
also a few lines before and after it, if there are some), so others may
find the build step where things go wrong.
Please don't give something like: "I get a warning when comiling x"
as this won't give any direction to look at.
Don't send large files!
Do not send large files (>100KB) to the mailing lists, just place a note
that further data is available on request. Large files will only annoy a
lot of people on the list who are not interested in your specific problem.
If required, you will be asked for further data by the persons who really
can help you.
Don't send confidential information!
If you send captured data to the mailing lists, be sure they don't contain
any sensitive or confidential information like passwords or such.
Reporting Crashes on UNIX/Linux platforms
When reporting crashes with Ethereal, it is helpful if you supply the
traceback information (besides the information mentioned in
).
You can obtain this traceback information with the following commands:
& bt.txt
backtrace
^D
$
]]>
Type the characters in the first line verbatim! Those are
back-tics there!
backtrace is a gdb command. You should
enter it verbatim after the first line shown above, but it will not be
echoed. The ^D
(Control-D, that is, press the Control key and the D key
together) will cause gdb to exit. This will
leave you with a file called
bt.txt in the current directory.
Include the file with your bug report.
If you do not have gdb available, you
will have to check out your operating system's debugger.
You should mail the traceback to the
&EtherealDevMailList;
mailing list.
Reporting Crashes on Windows platforms
The Windows distributions don't contain the symbol files (.pdb), because
they are very large. For this reason it's not possible to create
a meaningful backtrace file from it. You should report your crash just
like other problems, using the mechanism from
.
Other sources of developer information
If you don't find the information you need inside this book, there are
various other sources of information:
have a look at the Ethereal source code
there are various documentation files on different topics inside the
source code, see all the README.xxx files
tool documentation of the various tools used
(e.g. manpages of sed, gcc, ...)
the different mailing lists
...