// WSDG Chapter Introduction

[[ChapterIntroduction]]

== Introduction

[[ChIntroIntro]]

=== Introduction

This chapter will provide a general overview of Wireshark development.

[[ChIntroWhatIs]]

=== What Is Wireshark?

Well, if you want to start Wireshark development, you might already
know what Wireshark is doing. If not, please have a look at the
link:{wireshark-users-guide-url}[Wireshark User’s Guide],
which will provide a lot of general information about it.

[[ChIntroPlatforms]]

=== Supported Platforms

Wireshark currently runs on most UNIX-like platforms and various Windows
platforms. It requires Qt, GLib, libpcap and some other libraries in
order to run.

As Wireshark is developed in a platform independent way and uses libraries (such
as the Qt GUI library) which are available for many different platforms,
it’s thus available on a wide variety of platforms.

If a binary package is not available for your platform, you should
download the source and try to build it. Please report your experiences
to mailto:{wireshark-dev-list-email}[].

Binary packages are available for the following platforms along with many
others:

==== Unix And Unix-like Platforms

* Apple macOS

* FreeBSD

* HP-UX

* IBM AIX

* NetBSD

* OpenBSD

* Oracle Solaris

===== Linux

* Arch Linux

* Debian GNU/Linux

* Ubuntu

* Fedora

* Gentoo Linux

* IBM S/390 Linux (Red Hat)

* Mandriva Linux

* PLD Linux

* Red Hat Linux

* Slackware Linux

* Suse Linux

==== Microsoft Windows

Wireshark supports Windows natively via the https://en.wikipedia.org/wiki/Windows_API[Windows API].
Note that in this documentation and elsewhere we tend to use the terms “Win32”, “Win”, and “Windows” interchangeably to refer to the Windows API.
“Win64” refers to the Windows API on 64-bit platforms.
Wireshark runs on and can be compiled on the following Windows versions:

* Windows 10 / Windows Server 2016 / Windows Server 2019

* Windows 8.1 / Windows Server 2012 R2

* Windows 8 / Windows Server 2012

Development on Windows 7, Server 2008 R2, Vista, Server 2008, and older versions may be possible but is not supported.

Some versions of Windows support https://devblogs.microsoft.com/commandline/per-directory-case-sensitivity-and-wsl/[case sensitive directories].
We don’t officially support building or running Wireshark in this environment, but we will accept patches to fix any issues that might arise.

[[ChIntroDevelopment]]

=== Development And Maintenance Of Wireshark

Wireshark was initially developed by Gerald Combs. Ongoing development
and maintenance of Wireshark is handled by the Wireshark core developers,
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 and other improvements to Wireshark, and it is
expected that this will continue. You can find a list of the people who
have contributed code to Wireshark by checking the About dialog box of
Wireshark, or have a look at the {wireshark-authors-url} page on the
Wireshark web site.

The communication between the developers is usually done through the developer
mailing list, which can be joined by anyone interested in the development
activities. At the time this document was written, more than 500 persons were
subscribed to this mailing list!

It is strongly recommended to join the developer mailing list, if you are going
to do any Wireshark development. See <<ChIntroMailingLists>> about the different
Wireshark mailing lists available.

==== Programming Languages Used

Most of Wireshark is implemented in C.
A notable exception is the code in _ui/qt_, which is written in {cpp}.

The typical task for a new Wireshark developer is to extend an existing dissector, or write a new dissector for a specific network protocol.
Most dissectors are written in C11, so a good knowledge of C will be sufficient for Wireshark development in almost any case.
Dissectors can also be written in Lua, which might be more suitable for your specific needs.
As noted above, if you’re going to modify Wireshark’s user interface you will need a knowledge of {cpp}.

Modifying the build system and support tooling might requires knowledge of CMake, Python, PowerShell, Bash, or Perl.
Note that these are required to build Wireshark, but not to run it.
If Wireshark is installed from a binary package, none of these helper tools are needed on the target system.

==== Open Source Software

Wireshark is an https://opensource.org/[open source] software (OSS) project, and is released under
the link:{gplv2-url}[GNU General Public License] (GPL).
You can freely use Wireshark 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 Wireshark, either as plugins, or built
into the source, and they often do!

You are welcome to modify Wireshark to suit your own needs, and it would be
appreciated if you contribute your improvements back to the Wireshark community.

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
  Wireshark have helped you and other people.

* The developers of Wireshark might improve your changes even more, as there’s
  always room for improvement. Or they may implement some advanced things on top
  of your code, which can be useful for yourself too.

* The maintainers and developers of Wireshark 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 Wireshark. So if Wireshark is updated
  (which is done often), you can get a new Wireshark version from the website
  and your changes will already be included without any effort for you.


The Wireshark source code and binary packages for some platforms are all
available on the download page of the Wireshark website:
{wireshark-download-url}.


[[ChIntroReleases]]

=== Releases And Distributions

Official Wireshark releases can be found at {wireshark-download-url}.
Minor releases typically happen every six weeks and typically include bug fixes and security updates.
Major releases happen about once a year and include new features and new protocol support.
Official releases include binary packages for Windows and macOS along with source code.

[[ChIntroReleaseBinary]]

==== Binary Distributions

The Wireshark development team would like to make it as easy as possible for people to obtain and use Wireshark.
This means that we need to support the software installation systems that different operating systems provide.
We currently offer the following types of precompiled packages as part of each official release:

* Windows .exe installer.
  This is an executable file that installs Wireshark, and optionally Npcap and USBPcap, created using https://nsis.sourceforge.io/Main_Page[NSIS].
  It is the most popular installation method on Windows.

* Windows https://portableapps.com/[PortableApps] .paf.exe file.
  This is a self-contained package that can be run from anywere, either standalone or under the PortableApps.com Platform.

* Windows .msi installer.
  This installs Wireshark using Microsoft’s https://docs.microsoft.com/en-us/windows/win32/msi/installer-database[Installer Database], created using the https://wixtoolset.org/[WiX toolset].
  It does not yet include Npcap or USBPcap and is somewhat https://gitlab.com/wireshark/wireshark/-/issues/8814[experimental].

* macOS .dmg.
  This is a disk image which includes a drag-installable Wireshark application bundle along with utility packages for installing ChmodBPF and adding Wireshark to your PATH environment variable.

Most Linux and UNIX distributions have their own packaging systems which usually include Wireshark.
The Wireshark sources include support for creating the following types of packages:

* Debian .deb files.
  Packaging assets can be found in the _debian_ directory in the Wireshark sources.

* Red Hat .rpm files.
  Packaging assets can be found in the _packaging/rpm_ directory in the Wireshark sources.

You can also create your own binary packages. See <<ChSrcBinary>> for details.

[[ChIntroReleaseSource]]

==== The Source Code Distribution

Wireshark is and will always be https://opensource.org/[open source].
You’re welcome to download a source tarball, build it, and modify it under the terms of the {gplv2-url}[GPLv2].
However, it’s usually much easier to use a binary package if you want to get up and running quickly in a production environment.

Source tarballs are commonly used for building the binary packages for UNIX and UNIX-like platforms.
However, if you are going to modify the Wireshark sources, e.g. to contribute changes back or to develop an in-house version of Wireshark we recommend that you use the latest Git sources.
For details about the different ways to get the Wireshark source code see <<ChSrcObtain>>.

Before building Wireshark from a source distribution, make sure you have all the tools and libraries required to build.
Later chapters describe the required tools and libraries in detail.

[[ChIntroAutomated]]

=== Automated Builds (GitLab CI And Buildbot)

The Wireshark development team uses GitLab’s continuous integration (CI) system and Buildbot to automatically build Wireshark for each Git merge request and commit. Automated builds provide several useful services:

* Cross-platform testing.
  Inbound merge requests and commits can be tested on each of our supported plaforms, which ensures that a developer on one platform doesn’t break the build on other platforms.

* A health indicator for the source code.
  The CI badges at https://gitlab.com/wireshark/wireshark/ and the waterfall status at https://buildbot.wireshark.org/wireshark-master/ can quickly tell you how healthy the latest code is. Green is good, red is bad.

* Fast code delivery.
  After a change is committed to the repository, an installer is usually available within an hour at https://www.wireshark.org/download/automated/.
  This can be quite helpful for resolving issues, e.g. a bug reporter can easily verify a bugfix by installing a recent build.

* Automated regression tests.
  We run a comprehensive test suite as part of each build and continuously run fuzz tests that try to crash the dissection engine.

==== What Do The Automated Builds Do?

GitLab’s CI and Buildbot operate by running a series of steps and reporting success or failure. A typical CI job might do the following:

. Check out Wireshark from the source repository.

. Build Wireshark.

. Create a source tarball, binary package, or installer.

. Run regression tests.

GitLab’s CI marks successful jobs with a green checkmark and failed jobs with a red “X”.
Buildbot similarly colors successful jobs and steps green and failed ones red.
Jobs and steps provide a link to the corresponding console logfile which provides additional information.

Release packages are built on the following platforms:

* Windows Server 2019 x86-64 (Win32, little endian, Visual Studio 2019)

* Windows Server 2019 x86-64 (Win64, little endian, Visual Studio 2019)

* Ubuntu 18.04 x86-64 (Linux, little endian, gcc, Clang)

* macOS 10.14 x86-64 (BSD, little endian, Clang)

Static code analysis and fuzz tests are run on the following platforms:

* Visual Studio Code Analysis (Win64, little endian, VS 2019)

* Clang Code Analysis, Coverity Scan, and fuzz tests (Linux, little endian, Clang)

Each platform is represented at the status page by a single column, the most recent entries are at the top.

[[ChIntroHelp]]


=== Reporting problems and getting help

If you have problems, or need help with Wireshark, there are several
places that may be of interest to you (well, beside this guide of
course).

[[ChIntroHomepage]]

==== Website

You will find lots of useful information on the Wireshark homepage at
{wireshark-main-url}.

[[ChIntroWiki]]

==== Wiki

The Wireshark Wiki at {wireshark-wiki-url} provides a wide range
of information related to Wireshark and packet capturing in general.
You will find a lot of information not part of this developer’s guide. For
example, there is an explanation how to capture on a switched network,
an ongoing effort to build a protocol reference and a lot more.

And best of all, if you would like to contribute your knowledge on a
specific topic (maybe a network protocol you know well), you can edit the
Wiki pages by simply using your webbrowser.

[[ChIntroFAQ]]


==== FAQ

The "Frequently Asked Questions" will list often asked questions and
the corresponding answers.

Before sending any mail to the mailing lists below, be sure to read the
FAQ, as it will often answer any questions 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 Wireshark by clicking the menu item
Help/Contents and selecting the FAQ page in the upcoming dialog.

An online version is available at the Wireshark website:
{wireshark-faq-url}. You might prefer this online version as it’s
typically more up to date and the HTML format is easier to use.

[[ChIntroOtherSources]]

==== Other sources

If you don't find the information you need inside this book, there are
various other sources of information:

* The file _doc/README.developer_ and all the other README.xxx files in the
  source code. These are various documentation files on different topics

[NOTE]
.Read the README
====
_README.developer_ is packed full with all kinds of details relevant
to the developer of Wireshark source code. Its companion file
_README.dissector_ advises you around common
pitfalls, shows you basic layout of dissector code, shows details of the
APIs available to the dissector developer, etc.
====

* The Wireshark source code

* Tool documentation of the various tools used
(e.g. manpages of sed, gcc, etc.)

* The different mailing lists. See <<ChIntroMailingLists>>

[[ChIntroQA]]

==== Q&amp;A Site

The Wireshark Q&amp;A site at {wireshark-qa-url} offers a resource where
questions and answers come together. You have the option to search what
questions were asked before and what answers were given by people who
knew about the issue. Answers are graded, so you can pick out the best
ones easily. If your issue isn't discussed before you can post one
yourself.

[[ChIntroMailingLists]]

==== Mailing Lists

There are several mailing lists available on specific Wireshark topics:

wireshark-announce:: This mailing list will inform you about new program
releases, which usually appear about every 4-8 weeks.

wireshark-users:: This list is for users of Wireshark. People post
questions about building and using Wireshark, others (hopefully)
provide answers.

wireshark-dev:: This list is for Wireshark developers. People post questions about
the development of Wireshark, others (hopefully) provide answers.
If you want to start developing a protocol dissector, join this list.

wireshark-bugs:: This list is for Wireshark developers. Every time a change to the bug
database occurs, a mail to this mailing list is generated.
If you want to be notified about all the changes to the bug
database, join this list. Details about the bug database can be
found in <<ChIntroBugDatabase>>.

wireshark-commits:: This list is for Wireshark developers. Every time a change to the Git
repository is checked in, a mail to this mailing list is generated.
If you want to be notified about all the changes to the Git
repository, join this list. Details about the Git repository can be
found in <<ChSrcGitRepository>>.

You can subscribe to each of these lists from the Wireshark web site:
{wireshark-mailing-lists-url}. From there, you can choose which mailing
list you want to subscribe to by clicking on the
Subscribe/Unsubscribe/Options button under the title of the relevant
list. The links to the archives are included on that page as well.

[TIP]
.The archives are searchable
====
You can search in the list archives to see if someone previously asked the same
question and maybe already got an answer. That way you don't have to wait until
someone answers your question.
====

[[ChIntroBugDatabase]]

==== Bug database (Gitlab Issues)

The Wireshark community collects bug reports in an issues database at
{wireshark-bugs-url}. This database is filled with manually filed bug
reports, usually after some discussion on wireshark-dev, and automatic
bug reports from the Buildbot tools.

[[ChIntroReportProblems]]

==== Reporting Problems

[NOTE]
.Test with the latest version
====
Before reporting any problems, please make sure you have installed the
latest version of Wireshark. Reports on older maintenance releases are
usually met with an upgrade request.
====

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 compile/run Wireshark
on a lot of different platforms.

When reporting problems with Wireshark, it is helpful if you supply the
following information:

. The version number of Wireshark and the dependent libraries linked with
it, e.g. Qt, GLib, etc. You can obtain this with the command
`wireshark -v`.

. Information about the platform you run Wireshark 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 compiling x"
as this won't give any direction to look at.

[NOTE]
.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.
====

[WARNING]
.Don't send confidential information
====
If you send captured data to the mailing lists, or add it to your bug report,
be sure it doesn't contain any sensitive or confidential information,
such as passwords.  Visibility of such files can be limited to certain
groups in the Gitlab Issues database by marking the issue confidential.
====

==== Reporting Crashes on UNIX-like platforms

When reporting crashes with Wireshark, it is helpful if you supply the
traceback information (besides the information mentioned in
<<ChIntroReportProblems>>).

You can obtain this traceback information with the following commands:

----
$ gdb `whereis wireshark | cut -f2 -d: | cut -d' ' -f2` core >& bt.txt
backtrace
^D
$
----

[NOTE]
.Using GDB
====
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 mailto:{wireshark-dev-list-email}[] or attach it
to your bug report.

==== Reporting Crashes on Windows platforms

You can download Windows debugging symbol files (.pdb) from the following locations:

* 32-bit Windows: https://www.wireshark.org/download/win32/all-versions/

* 64-bit Windows: https://www.wireshark.org/download/win64/all-versions/

Files are named "Wireshark-pdb-win__bits__-_x_._y_._z_.zip" to match their
corresponding "Wireshark-win__bits__-_x_._y_._z_.exe" installer packages.

// XXX Show how to use the Visual Studio debugger

// End of WSDG Chapter Introduction
