Enhance NXT DNS Type

[metze/wireshark/wip.git] / docbook / wsdg_src / WSDG_chapter_sources.xml

<!-- WSDG Chapter Sources -->
<!-- $Id$ -->

<chapter id="ChapterSources">
  <title>Work with the Wireshark sources</title>

  <section id="ChSrcIntro">
        <title>Introduction</title>
        <para>
        This chapter will explain how to work with the Wireshark source code.
        It will show you how to:
        <itemizedlist>
        <listitem><para>
        get the source
        </para></listitem>
        <listitem><para>
        compile the source
        </para></listitem>
        <listitem><para>
        submit changes
        </para></listitem>
        <listitem><para>
        ...
        </para></listitem>
        </itemizedlist>
        However, this chapter will not explain the source file contents in detail,
        such as where to find a specific functionality. This is done in
        <xref linkend="ChCodeOverview"/>.
        </para>
  </section>

  <section id="ChSrcSVNServer">
        <title>The Wireshark Subversion repository</title>
        <para>
        Subversion is used to keep track of the changes made to the Wireshark
        source code. The Wireshark source code is stored inside Wireshark project's
        Subversion repository located at a server at the wireshark.org domain.
        </para>
        <para>
        To quote the Subversion book about "What is Subversion?":
        </para>
        <para>
        <quote>Subversion is a free/open-source version control system. That is,
        Subversion manages files and directories over time. A tree of files is
        placed into a central repository. The repository is much like an ordinary
        file server, except that it remembers every change ever made to your files
        and directories. This allows you to recover older versions of your data,
        or examine the history of how your data changed. In this regard, many
        people think of a version control system as a sort of "time machine".
        </quote>
        </para>
        <tip><title>Tip: Subversion and SVN is the same!</title>
        <para>
        Subversion is often abbreviated as SVN, as the command-line tools are
        abbreviated that way. You will find both terms with the same meaning in
        this book, in mailing list discussions and elsewhere.
        </para>
        </tip>
        <para>
        Using Wireshark's Subversion repository you can:
        <itemizedlist>
        <listitem><para>
        keep your private sources up to date with very little effort
        </para></listitem>
        <listitem><para>
        get a mail notification if someone changes the latest sources
        </para></listitem>
        <listitem><para>
        get the source files from any previous release (or any other point in time)
        </para></listitem>
        <listitem><para>
        have a quick look at the sources using a web interface
        </para></listitem>
        <listitem><para>
        see which person changed a specific piece of code
        </para></listitem>
        <listitem><para>
        ... and a lot more things related to the history of the Wireshark source
        code development
        </para></listitem>
        </itemizedlist>
        </para>
        <para>
        Subversion is divided into a client and a server part.
        Thanks to Gerald Combs (the maintainer of the Subversion server),
        no user has to deal with the maintenance of the Subversion server.
        You will only need a Subversion client, which is available as
        both a command-line and a GUI tool for many different platforms.
        </para>
        <para>
        For further reference about Subversion, have a look at the homepage of the
        Subversion project: <ulink url="http://subversion.apache.org/"/>. There
        is a good and free book about it available at: <ulink
        url="http://svnbook.red-bean.com/"/>.
        </para>
        <para>
        Please note that Wireshark's public (anonymous) Subversion repository is
        separate from the main repository.
        It may take several minutes for committed changes to appear in the
        public repository - so please be patient for a few minutes if you
        desperately need a code change that was committed to the repository
        very recently.
        </para>

  <section id="ChSrcWebInterface">
        <title>The web interface to the Subversion repository</title>
        <para>
        If you need a quick look at the Wireshark source code,
        you will only need a Web browser.
        </para>
        <para>
        A <literal>simple view</literal> on the latest developer version can be
        found at:
        </para>
        <para>
        <ulink url="http://anonsvn.wireshark.org/wireshark/trunk/"/>.
        </para>
        <para>
        A <literal>comprehensive view</literal> of all source versions
        (e.g. including the capability to show differences between versions)
        is available at:
        </para>
        <para>
        <ulink url="http://anonsvn.wireshark.org/viewvc/viewvc.cgi/"/>.
        </para>
        <para>
        Of special interest might be the subdirectories:
        <itemizedlist>
        <listitem><para>
        <filename>trunk</filename> - the very latest source files
        </para></listitem>
        <listitem><para>
        <filename>releases</filename> - the source files of all released versions
        </para></listitem>
        </itemizedlist>
        </para>
  </section>
  </section>

  <section id="ChSrcObtain">
        <title>Obtain the Wireshark sources</title>
        <para>
        There are several ways to obtain the sources from Wireshark's Subversion
        server.
        </para>
        <tip><title>Anonymous Subversion access is recommended!</title>
        <para>
        It can make your life much easier, compared to updating your source tree by
        using any of the zip file methods mentioned below.
        Subversion handles merging of changes into your personal source tree in a
        very comfortable and quick way. So you can update your source tree several
        times a day without much effort.
        </para>
        </tip>
        <note><title>Keep your sources "up to date"!</title>
        <para>
        The following ways to retrieve the Wireshark sources are sorted in
        decreasing source timeliness.
        If you plan to commit changes you've made to the sources,
        it's a good idea to keep your private source tree as current as possible.
        </para>
        </note>
        <para>
        The age mentioned in the following sections indicates the age of the
        most recent change in that set of the sources.
        </para>

        <section id="ChSrcAnon">
        <title>Anonymous Subversion access</title>
        <para>
        Recommended for development purposes.
        </para>
        <para>
        Age: a few minutes.
        </para>
        <para>
        You can use a Subversion client to download the source code from
        Wireshark's anonymous Subversion repository. The URL for the repository
        trunk is:
        <ulink url="&WiresharkRepositorySite;/wireshark/trunk/"/>.
        </para>
        <para>
        See <xref linkend="ChToolsSubversion"/> on how to install a Subversion client.
        </para>
        <para>
        For example, to check out using the command-line Subversion client, you
        would type:
        </para>
        <para>
        <prompt>$</prompt>
        <userinput>svn checkout &WiresharkRepositorySite;/wireshark/trunk wireshark</userinput>
        </para>
        <para>
        The checkout has to be only done once. This will copy all the sources of
        the latest version (including directories) from the server to your machine.
        This will take some time, depending on the speed of your internet connection.
        </para>
        </section>

        <section id="ChSrcSVNWeb">
        <title>Anonymous Subversion web interface</title>
        <para>
        Recommended for informational purposes only, as only individual files can
        be downloaded.
        </para>
        <para>
        Age: a few minutes (same as anonymous Subversion access).
        </para>
        <para>
         The entire source tree of the Subversion repository is available via a
         web interface at:
         <ulink url="&WiresharkRepositorySite;/viewvc/viewvc.cgi/"/>.
         You can view each revision of a particular file, as well as diffs between
         different revisions.
         You can also download individual files but not entire directories.
        </para>
        </section>

        <section id="ChSrcBuildbot">
        <title>Buildbot Snapshots</title>
        <para>
        Recommended for development purposes, if direct Subversion access isn't
        possible (e.g. because of a restrictive firewall).
        </para>
        <para>
        Age: some number of minutes (a bit older than the anonymous Subversion access).
        </para>
        <para>
        The buildbot server will automatically start to generate a snapshot of
        Wireshark's source tree after a source code change is committed.
        These snapshots can be found at: <ulink
        url="&WiresharkDownloadPage;automated/src/"/>.
        </para>
        <para>
        If anonymous Subversion access isn't possible, e.g. if the connection to
        the server isn't possible because of a corporate firewall, the sources
        can be obtained by downloading the buildbot snapshots. However, if you are
        going to maintain your sources in parallel to the "official" sources
        for some time, it's recommended to use the anonymous Subversion access if
        possible (believe it, it will save you a lot of time).
        </para>
        </section>


        <section id="ChSrcReleased">
        <title>Released sources</title>
        <para>
        Recommended for productive purposes.
        </para>
        <para>
        Age: from days to weeks.
        </para>
        <para>
        The officially released source files can be found at: <ulink
        url="&WiresharkDownloadPage;"/>.
        You should use these sources if you want to build Wireshark on your
        platform for productive use.
        </para>
        <para>
        The differences between the released sources and the sources stored at
        the Subversion repository will keep on growing until the next release is
        done (at the release time, the released and latest Subversion repository
        versions are then identical again :-).
        </para>
        </section>

  </section>

  <section id="ChSrcUpdating">
        <title>Update the Wireshark sources</title>
        <para>
        After you've obtained the Wireshark sources for the first time, you
        might want to keep them in sync with the sources at the Subversion
        repository.
        </para>
        <tip><title>Take a look at the buildbot first!</title>
        <para>
        As development evolves, the Wireshark sources are compilable most of the
        time - but not always.
        You may take a look at the <xref linkend="ChIntroAutomated"/> first,
        to see if the sources are currently in a good shape.
        </para>
        </tip>

        <section id="ChSrcAnonUpdate">
        <title>... with Anonymous Subversion access</title>
        <para>
        After the first time checkout is done, updating your
        sources is simply done by typing (in the Wireshark source dir):
        </para>
        <para>
        <prompt>$</prompt>
        <userinput>svn update</userinput>
        </para>
        <para>
        This will only take a few seconds, even on a slow internet connection. It will
        replace old file versions by new ones. If you and someone else have
        changed the same file since the last update, Subversion will try to merge
        the changes into your private file (this works remarkably well).
        </para>
        </section>

        <section id="ChSrcZipUpdate">
        <title>... from zip files</title>
        <para>
        Independent of the way you retrieve the zip file of the Wireshark sources
        (as described in <xref linkend="ChSrcObtain"/> ), the way to
        bring the changes from the official sources into your personal source tree
        is identical.
        </para>
        <para>
        First of all, you will download the new zip file of the official sources
        the way you did it the first time.
        </para>
        <para>
        If you haven't changed anything in the sources, you could simply throw
        away your old sources and reinstall everything just like the first time.
        But be sure, that you really haven't changed anything. It might be a good
        idea to simply rename the "old" dir to have it around, just in case you
        remember later that you really did change something before.
        </para>
        <para>
        Well, if you did change something in your source tree, you have to merge
        the official changes
        since the last update into your source tree. You will install the content
        of the zip file into a new directory and use a good merge tool (e.g.
        <ulink url="http://winmerge.sourceforge.net/"/> for Win32) to bring
        your personal source tree in sync with the official sources again.
        </para>
        </section>

  </section>

  <section id="ChSrcBuildFirstTime">
        <title>Build Wireshark</title>
        <para>
        The sources contain several documentation files, it's a good idea to
        look at these files first.
        </para>
        <para>
        So after obtaining the sources, tools and libraries, the
        first place to look at is <filename>doc/README.developer</filename>,
        here you will get the latest infos for Wireshark development for all
        supported platforms.
        </para>
        <tip><title>Tip!</title>
        <para>
        It is a very good idea, to first test your complete build environment
        (including running and debugging Wireshark) before doing any changes
        to the source code (unless otherwise noted).
        </para>
        </tip>
        <para>
        The following steps for the first time generation differ on the two
        major platforms.
        </para>

        <section>
        <title>Unix</title>
        <para>
        Run the autogen.sh script at the top-level wireshark directory to configure
        your build directory.
        <programlisting>
./autogen.sh
./configure
make
        </programlisting>
        </para>
        <para>
        If you need to build with a non-standard configuration, you can use:
        <programlisting>
./configure --help
        </programlisting>
        to see what options you have.
        </para>
        </section>

        <section>
        <title>Win32 native</title>
        <para>
        The first thing to do will be to check the file
        <filename>config.nmake</filename> to determine if it reflects your configuration.
        The settings in this file are well documented, so please have a look at
        that file.
        However, if you've installed the libraries and tools as recommended there
        should be no need to edit things here.
        </para>
        <para>
        Many of the file and directory names used in the build process go past the
        old 8.3 naming limitations.
        As a result, you should use the <command>cmd.exe</command> command interpreter
        instead of the old <command>command.com</command>.
        </para>
        <para>
        Be sure that your command-line environment is set up to compile
        and link with MSVC++. When installing MSVC++, you can have your
        system's environment set up to always allow compiling from the
        command line, or you can invoke the vcvars32.bat script, which can
        usually be found in the <filename>VC98\Bin</filename> subdirectory of the
        directory in which Visual Studio was installed.
        </para>
        <para>
        You should then cleanup any intermediate files, which are shipped for
        convenience of Unix users, by typing at the command line prompt (cmd.exe):
        </para>
        <para>
        <prompt>&gt;</prompt> <userinput>nmake -f Makefile.nmake distclean</userinput>
        </para>
        <para>
        After doing this, typing at the command line prompt (cmd.exe):
        </para>
        <para>
        <prompt>&gt;</prompt> <userinput>nmake -f Makefile.nmake all</userinput>
        </para>
        <para>
        will start the whole Wireshark build process.
        </para>
        <para>
        After the build process has successfully finished, you should find a
        <filename>wireshark.exe</filename> and some other files
        in the root directory.
        </para>
        </section>

  </section>

  <section id="ChSrcRunFirstTime">
        <title>Run generated Wireshark</title>
        <tip><title>Tip!</title>
        <para>
        An already installed Wireshark may interfere with your newly generated
        version in various ways. If you have any problems getting your Wireshark
        running the first time, it might be a good idea to remove the previously
        installed version first.
        </para>
        </tip>
        <section id="ChSrcRunFirstTimeUnix">
        <title>Unix/Linux</title>
        <para>
        After a successful build you can run Wireshark right from the build
        directory. Still the program would need to know that it's being run from
        the build directory and not from its install location. This has inpact
        on the directories where the program can find the other parts and
        relevant data files.
        </para>
        <para>
        In order to run the Wireshark from the build directory set the environment
        variable <varname>WIRESHARK_RUN_FROM_BUILD_DIRECTORY</varname> and run
        Wireshark. If your platform is properly setup, your build directory and
        current working directory are not in your <varname>PATH</varname>, so the
        commandline to launch Wireshark would be:
        <command>WIRESHARK_RUN_FROM_BUILD_DIRECTORY=1 ./wireshark</command>.
        </para>
        <para>
        There's no need to run Wireshark as root user, you just won't be able to
        capture. When you opt to run Wireshark this way, your terminal output can
        be informative when things don't work as expected.
        </para>
        </section>
        <section id="ChSrcRunFirstTimeWin32">
        <title>Win32 native</title>
        <para>
        During the build all relevant program files are collected in a subdirectory
        <command>wireshark-gtk2</command>. You can run the program from there by
        launching the wireshark.exe executable.
        </para>
        </section>
  </section>

  <section id="ChSrcDebug">
        <title>Debug your generated Wireshark</title>
        <section id="ChSrcUnixDebug">
        <title>Unix/Linux</title>
        <para>
        When you want to investigate a problem with Wireshark you want to load
        the program into your debugger. But loading wireshark into debugger fails
        because of the libtool build environment. You'll have to wrap loading
        wireshark into a libtool command:
        <command>libtool --mode=execute gdb wireshark</command>
        </para>
        <para>
        If you prefer a graphic debugger you can use the Data Display Debugger
        (ddd) instead of GNU debugger (gdb).
        </para>
        <para>
        Additional traps can be set on GLib by setting the <varname>G_DEBUG</varname>
        environment variable:<command>G_DEBUG=fatal_criticals libtool --mode=execute
        ddd wireshark</command>.
        See <ulink url="http://library.gnome.org/devel/glib/stable/glib-running.html"/>
        </para>
        </section>

        <section id="ChSrcWin32Debug">
        <title>Win32 native</title>
        <para>
        XXX - add more info here.
        </para>
        </section>
  </section>

  <section id="ChSrcChange">
        <title>Make changes to the Wireshark sources</title>
        <para>
        As the Wireshark developers are working on many different platforms, a lot of
        editors are used to develop Wireshark (emacs, vi, Microsoft Visual Studio
        and many many others). There's no "standard" or "default" development
        environment.
        </para>
        <para>
        There are several reasons why you might want to change the Wireshark
        sources:
        <itemizedlist>
          <listitem><para>add your own new dissector</para></listitem>
          <listitem><para>change/extend an existing dissector</para></listitem>
          <listitem><para>fix a bug</para></listitem>
          <listitem><para>implement a new glorious feature :-)</para></listitem>
        </itemizedlist>
        The internal structure of the Wireshark sources will be described in
        <xref linkend="PartDevelopment"/>.
        </para>
        <tip><title>Tip!</title>
        <para>
        <literal>Ask the developer mailing list before you really start a new
        development task.</literal>
        If you have an idea what you want to add/change, it's a good idea to
        contact the developer mailing list
        (see <xref linkend="ChIntroMailingLists"/>)
        and explain your idea. Someone else might already be working on the same
        topic, so double effort can be reduced, or someone can give you some tips that
        should be thought about (like side effects that are sometimes very
        hard to see).
        </para>
        </tip>
  </section>

  <section id="ChSrcContribute">
        <title>Contribute your changes</title>
        <para>
        If you have finished changing the Wireshark sources to suit your needs,
        you might want to contribute your changes back to the Wireshark
        community. You gain the following benefits by contributing your improvements:
        <itemizedlist>
        <listitem><para>
        It's the right thing to do. 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.
        </para></listitem>
        <listitem><para>
        You get free enhancements. By making your code public, other developers
        have a chance to make improvements, as there's always room for
        improvements. In addition someone may implement advanced features on top of
        your code, which can be useful for yourself too.
        </para></listitem>
        <listitem><para>
        You save time and effort. The maintainers and developers of Wireshark
        will maintain your code as well, updating 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.
        </para></listitem>
        </itemizedlist>
        There's no direct way to commit changes to the SVN repository. Only a few
        people are authorised to actually
        make changes to the source code (check-in changed files). If you want
        to submit your changes, you should make a diff file (a patch) and upload it to the bug tracker.
        </para>

        <section id="ChSrcDiffWhat">
        <title>What is a diff file (a patch)?</title>
        <para>
        A <ulink url="http://en.wikipedia.org/wiki/Diff">diff file</ulink>
        is a plain text file containing the differences between a pair of files
        (or a multiple of such file pairs).
        <tip><title>Tip!</title>
        <para>A diff file is often also called a patch,
        as it can be used to patch an existing source file or tree with changes
        from somewhere else.
        </para>
        </tip>
        </para>
        <para>
        The Wireshark community is using patches to transfer source code changes
        between the authors.
        </para>
        <para>
        A patch is both readable by humans and (as it is specially formatted) by
        some dedicated tools.
        </para>
        <para>
        Here is a small example of a patch for <filename>file.h</filename> that
        makes the second argument in <function>cf_continue_tail()</function>
        <type>volatile</type>.  It was created using <command>svn diff</command>,
        described below:
        <programlisting>
<![CDATA[
Index: file.h
===================================================================
--- file.h      (revision 21134)
+++ file.h      (revision 22401)
@@ -142,7 +142,7 @@
  * @param err the error code, if an error had occurred
  * @return one of cf_read_status_t
  */
-cf_read_status_t cf_continue_tail(capture_file *cf, int to_read, int *err);
+cf_read_status_t cf_continue_tail(capture_file *cf, volatile int to_read, int *err);

 /**
  * Finish reading from "end" of a capture file.
]]>
        </programlisting>
        The plus sign at the start of a line indicates an added line, a minus
        sign indicates a deleted line compared to the original sources.
        </para>
        <para>
        We prefer to use so called "unified" diff files in Wireshark development,
        three unchanged lines before and after the actual changed parts are
        included. This makes it much easier for a merge/patch tool to find
        the right place(s) to change in the existing sources.
        </para>
        </section>


        <section id="ChSrcGeneratePatch">
        <title>Generate a patch</title>
        <para>
        There are several ways to generate patches. The preferred way is to
        generate them from an updated Subversion tree, since it avoids
        unnecessary integration work.
        </para>

        <section id="ChSrcSVNDiff">
        <title>Using the svn command-line client</title>
        <para>
        <userinput>svn diff [changed_files] > svn.diff</userinput>
        </para>
        <para>
        Use the command line svn client to generate a patch in the required format
        from the changes you've made to your working copy. If you leave out the
        name of the changed file the svn client searches for all changes in the
        working copy and usually produces a patch containing more than just the
        change you want to send. Therefore you should always check the produced
        patch file.
        </para>
        <para>
        If you've added a new file, e.g.
        <filename>packet-myprotocol.c</filename>, you can use <command>svn
        add</command> to add it to your local tree before generating the patch.
        Similarly, you can use <command>svn rm</command> for files that should
        be removed.
        </para>
        </section>

        <section id="ChSrcSVNGUIDiff">
        <title>Using the diff feature of the GUI Subversion clients</title>
        <para>
        Most (if not all) of the GUI Subversion clients (RapidSVN, TortoiseSVN, ...)
        have a built-in "diff" feature.
        </para>
        <para>
        If you use TortoiseSVN:
        </para>
        <para>
        TortoiseSVN (to be precise Subversion) keeps track of the files you have
        changed in the directories it controls, and will generate for you a
        unified diff file compiling the differences. To do so - after updating
        your sources from the SVN repository if needed - just right-click on the
        highest level directory and choose "TortoiseSVN" -> "Create patch...".
        You will be asked for a name and then the diff file will be created. The
        names of the files in the patch will be relative to the directory you have
        right-clicked on, so it will need to be applied on that level too.
        </para>
        <para>
        When you create the diff file, it will include any difference TortoiseSVN
        finds in files in and under the directory you have right-clicked on, and
        nothing else. This means that changes you might have made for your
        specific configuration - like modifying <filename>config.nmake</filename>
        so that it uses
        your lib directory - will also be included, and you will need to remove
        these lines from the diff file. It also means that only changes will be
        recorded, i.e. if you have created new files -say, a new
        <filename>packet-xxx.c</filename> for a
        new protocol dissector- it will not be included in the diff, you need to
        add it separately. And, of course, if you have been working separately in
        two different patches, the .diff file will include both topics, which is
        probably not a good idea.
        </para>
        </section>

        <section id="ChSrcDiff">
        <title>Using the diff tool</title>
        <para>
        A diff file is generated, by comparing two files or directories between
        your own working copy and the "official" source tree. So to be able to
        do a diff, you should
        have two source trees on your computer, one with your working copy
        (containing your changes), and one with the "official" source tree
        (hopefully the latest SVN files) from &WiresharkWebSite;.
        </para>
        <para>
        If you have only changed a single file, you could type something like
        this:
        </para>
        <para>
        <userinput>diff -r -u --strip-trailing-cr svn-file.c work-file.c &gt; foo.diff</userinput>
        </para>
        <para>
        To get a diff file for your complete directory (including
        subdirectories), you could type something like this:
        </para>
        <para>
        <userinput>diff -N -r -u --strip-trailing-cr ./svn-dir ./working-dir &gt; foo.diff</userinput>
        </para>
        <para>
        It's a good idea to do a <userinput>make distclean</userinput> before the
        actual diff call, as this will remove a lot
        of temporary files which might be otherwise included in the diff. After
        doing the diff, you should edit the <filename>foo.diff</filename>
        file and remove unnecessary things, like your private changes to the
        <filename>config.nmake</filename> file.
        </para>
        <para>
        <table frame='all'><title>Some useful diff options</title>
        <tgroup cols='2' align='left' colsep='1' rowsep='1'>
        <colspec colname='c1'/>
        <colspec colname='c2'/>
        <thead>
        <row>
          <entry>Option</entry>
          <entry>Purpose</entry>
        </row>
        </thead>
        <tbody>
        <row>
          <entry>-N</entry>
          <entry>Add new files when used in conjunction with -r.</entry>
        </row>
        <row>
          <entry>-r</entry>
          <entry>Recursively compare any subdirectories found.</entry>
        </row>
        <row>
          <entry>-u</entry>
          <entry>Output unified context.</entry>
        </row>
        <row>
          <entry>--strip-trailing-cr</entry>
          <entry>Strip trailing carriage return on input. This is useful for Win32
          </entry>
        </row>
        <row>
          <entry>-x PAT</entry>
          <entry>Exclude files that match PAT.
          This could be something like -x *.obj to exclude all win32 object files.
          </entry>
        </row>
        </tbody>
        </tgroup>
        </table>
        </para>
        <para>
        The diff tool has a lot options; they can be listed with:
        </para>
        <para>
        <userinput>diff --help</userinput>
        </para>
        </section>

        </section>

        <section id="ChSrcGoodPatch">
        <title>Some tips for a good patch</title>
        <para>
        Some tips that will make the merging of your changes into the
        SVN tree much more likely (and you want exactly that, don't you :-):
        <itemizedlist>
          <listitem><para>
          <command>Use the latest SVN sources, or alike.</command>
          It's a good idea to work with the same sources that are used by the
          other developer's, this makes it usually much easier to apply your
          patch. For information about the different ways to get the sources,
          see <xref linkend="ChSrcObtain"/>.
          </para></listitem>
          <listitem><para>
          <command>Update your SVN sources just before making a patch.
          </command> For the same reasons as the previous point.
          </para></listitem>
          <listitem><para>
          <command>Do a "make clean" before generating the patch.</command>
          This removes a lot of unneeded intermediate files (like object files)
          which can confuse the diff tool generating a lot of unneeded stuff which
          you have to remove by hand from the patch again.
          </para></listitem>
          <listitem><para>
          <command>Find a good descriptive filename for your patch.</command>
          Think a moment to find a proper name for your patch file. Often a
          filename like <filename>wireshark.diff</filename> is used, which isn't
          really helpful if keeping several of these files and find the right
          one later. For example: If you want to commit changes to the datatypes
          of dissector foo, a good filename might be:
          <filename>packet-foo-datatypes.diff</filename>.
          </para></listitem>
          <listitem><para>
          <command>Don't put unrelated things into one large patch.
          </command> A few smaller patches are usually easier to apply (but also
          don't put every changed line into a separate patch :-).
          </para></listitem>
          <listitem><para>
          <command>Remove any parts of the patch not related to the
          changes you want to submit.</command> You can use a text editor for this.
          A common example for win32 developers are the differences in your private
          <filename>config.nmake</filename> file.
          </para></listitem>
        </itemizedlist>
        In general: making it easier to understand and apply your patch by one
        of the maintainers will make it much more likely (and faster) that it
        will actually be applied.
        </para>
        <para>
        Please remember: you don't pay the person "on the
        other side of the mail" for his/her effort applying your patch!
        </para>
        </section>

        <section id="ChSrcCodeRequirements">
        <title>Code Requirements</title>
        <para>
        The core maintainers have done a lot of work fixing bugs and making code
        compile on the various platforms Wireshark supports.
        </para>
        <para>
        To ensure Wireshark's source code quality, and to reduce the workload of
        the core maintainers, there are some things you should
        think about <command>before</command> submitting a patch.
        <warning><title>Warning!</title>
        <para>
        <command>Ignoring the code requirements will make it very likely
        that your patch will be rejected!</command>
        </para>
        </warning>
        <itemizedlist>
          <listitem><para>
          <command>Follow the Wireshark source code style guide.</command>
          Just because something compiles on your platform, that doesn't
          mean it'll compile on all of the other platforms for which Wireshark is
          built.
          Wireshark runs on many platforms, and can be compiled with a number of
          different compilers. See <xref linkend="ChCodeStyle"/> for details.
          </para>
          </listitem>
          <listitem><para>
          <command>Submit dissectors as built-in whenever possible.</command>
          Developing a new dissector as a plugin is a good idea because compiling is
          quicker, but it's best to convert dissectors to the built-in style before
          submitting for checkin. This reduces the number of files that must be installed
          with Wireshark and ensures your dissector will be available on all platforms.
          </para><para>
          This is no hard-n-fast rule though. Many dissectors are straightforward so they
          can easily be put into 'the big pile', while some are ASN.1 based which takes a
          different approach, and some multiple sourcefile dissectors are more suitable to
          be placed separate as plugin.
          </para>
          </listitem>
          <listitem><para>
          <command>Verify that your dissector code does not use prohibited or deprecated APIs</command>
          This can be done as follows:
          </para>
          <para>
          <userinput>perl &lt;wireshark_root&gt;/tools/checkAPIs.pl &lt;source-filename(s)&gt;</userinput>
          </para>
          </listitem>
          <listitem><para>
          <command>Fuzz test your changes!</command> Fuzz testing is a very
          effective way to automatically find a lot of dissector related bugs.
          You'll take a capture file containing packets affecting your dissector
          and the fuzz test will randomly change bytes in this file, so that unusual
          code paths in your dissector are checked. There are tools available to
          automatically do this on any number of input files, see:
          <ulink url="&WiresharkWikiSite;/FuzzTesting"/> for details.
          </para>
          </listitem>
        </itemizedlist>
        </para>
        </section>

        <section id="ChSrcSend">
        <title>Sending your patch for inclusion</title>
        <para>
        After generating a patch of your changes, you might want to have your
        changes included into the SVN repository.
        </para>
        <para>
        To submit a patch, open a new ticket in the Wireshark bug database at <ulink
        url="&WiresharkBugsSite;/bugzilla/enter_bug.cgi?product=Wireshark"/>.
        You must first create a bug, then attach your patch or patches.
        <itemizedlist>
          <listitem><para>
          Set the Product, Priority, and Severity as needed.
          </para></listitem>
          <listitem><para>
          Add a Summary and Description, and create a bug using the
          <guibutton>Commit</guibutton> button. If your code has passed fuzz
          testing, please say so in the description.
          </para></listitem>
          <listitem><para>
          Once the bug has been created, select <guibutton>Create a New Attachment</guibutton>
          and upload your patch or patches.  Set the <command>review_for_checkin</command>
          flag to <command>?</command>.  If you skip this step, your patch won't show up in the
          patch request queue.
          </para></listitem>
          <listitem><para>
          If possible and applicable, attach a capture file that demonstrates
          your new feature or protocol.
          </para></listitem>
          <listitem><para>
          Don't set the bug's status to ASSIGNED and don't assign the bug to
          yourself--if you do the latter, the core developers won't see the
          updates made to the bug.
          </para></listitem>
        </itemizedlist>
        </para>
        <!--
        <tip><title>Tip!</title>
        <para>
        Setting the <command>review_for_checkin</command> is important.
        Without it, your patch won't show up in the <ulink url="http://bugs.wireshark.org/bugzilla/request.cgi?action=queue&amp;requester=&amp;product=&amp;type=review_for_checkin&amp;requestee=&amp;component=&amp;group=type">pending
        patch request queue</ulink>.
        </para>
        </tip>
        -->
        <para>
        You might get one of the following responses to your patch request:
        <itemizedlist>
          <listitem><para>
          Your patch is checked into the SVN repository. Congratulations!
          </para></listitem>
          <listitem><para>
          You are asked to provide additional information, capture files, or
          other material. If you haven't fuzzed your code, you may be asked
          to do so.
          </para></listitem>
          <listitem><para>
          Your patch is rejected. You should get a response with the reason
          for rejection.  Common reasons include not following the style
          guide, buggy or insecure code, and code that won't compile on other
          platforms. In each case you'll have to fix each problem and upload
          another patch.
          </para></listitem>
          <listitem><para>
          You don't get any response to your patch.
          Possible reason: Don't worry, if your patch is in the bug tracker, it
          won't get lost.  But it may be that all the core developers are busy
          (e.g., with their day jobs or family or...) and haven't had time to
          look at your patch.  If you're concerned, feel free to add a comment
          to the patch or send an email to the developer's list asking for
          status.  But please be patient: most if not all of us do this in our
          "spare" time.
          </para></listitem>
        </itemizedlist>
        </para>
        </section>
  </section>

  <section id="ChSrcPatchApply">
        <title>Apply a patch from someone else</title>
        <para>
        Sometimes you need to apply a patch to your private source tree. Maybe
        because you want to try a patch from someone on the developer mailing
        list, or you want to check your own patch before submitting.
        </para>
        <warning><title>Warning!</title>
        <para>
        If you have problems applying a patch, make sure the line endings (CR/NL)
        of the patch and your source files match.
        </para>
        </warning>
        <section id="ChSrcPatchUse">
        <title>Using patch</title>
        <para>
        Given the file <filename>new.diff</filename> containing a unified diff,
        the right way to call the patch tool depends on what the pathnames in
        <filename>new.diff</filename> look like.
        If they're relative to the top-level source directory - for example, if a
        patch to <filename>prefs.c</filename> just has <filename>prefs.c</filename>
        as the file name - you'd run it as:
        </para>
        <para>
    <userinput>patch -p0 &lt;new.diff</userinput>
        </para>
        <para>
        If they're relative to a higher-level directory, you'd replace 0 with the
        number of higher-level directories in the path, e.g. if the names are
        <filename>wireshark.orig/prefs.c</filename> and
        <filename>wireshark.mine/prefs.c</filename>, you'd run it with:
        </para>
        <para>
    <userinput>patch -p1 &lt;new.diff</userinput>
        </para>
        <para>
        If they're relative to a <literal>subdirectory</literal> of the top-level
        directory, you'd run <command>patch</command> in <literal>that</literal>
        directory and run it with <parameter>-p0</parameter>.
        </para>
        <para>
        If you run it without <parameter>-p</parameter> at all, the patch tool
        flattens path names, so that if you
        have a patch file with patches to <filename>Makefile.am</filename> and
        <filename>wiretap/Makefile.am</filename>,
        it'll try to apply the first patch to the top-level
        <filename>Makefile.am</filename> and then apply the
        <filename>wiretap/Makefile.am</filename> patch to the top-level
        <filename>Makefile.am</filename> as well.
        </para>
        <para>
        At which position in the filesystem should the patch tool be called?
        </para>
        <para>
        If the pathnames are relative to the top-level source directory, or to a
        directory above that directory, you'd run it in the top-level source
        directory.
        </para>
        <para>
        If they're relative to a <literal>subdirectory</literal> - for example,
        if somebody did a patch to "packet-ip.c" and ran "diff" or "svn diff" in
        the "epan/dissectors" directory - you'd run it in that subdirectory.
        It is preferred that people <literal>NOT</literal> submit patches like
        that - especially if they're only patching files that exist in multiple
        directories, such as <filename>Makefile.am</filename>.
        </para>
        </section>
  </section>

  <section id="ChSrcAdd">
        <title>Add a new file to the Subversion repository</title>
        <para>
        The "usual" way to commit new files is described in <xref
        linkend="ChSrcContribute"/>. However, the following might be of
        interest for the "normal" developer as well.
        </para>
        <note><title>Note!</title>
        <para>
        This action is only possible/allowed by the Wireshark core developers who
        have write access to the Subversion repository. It is put in here to have
        all information in one place.
        </para>
        </note>
        <para>
        If you (as a core developer) need to add a file to the SVN repository,
        then you need to perform the following steps:
        <orderedlist>
        <listitem>
        <para>
        Verify that that file is complete (has Wireshark boilerplate, $Id$, etc).
        </para>
        </listitem>
        <listitem>
        <para>
        Add the new file(s) to the repository:
        </para>
        <para>
        <prompt>$</prompt>
        <userinput>svn add new_file</userinput>
        </para>
        </listitem>
        <listitem>
        <para>
        Set the line ending property to "native" for the new file(s):
        </para>
        <para>
        <prompt>$</prompt>
        <userinput>svn propset svn:eol-style native new_file</userinput>
        </para>
        </listitem>
        <listitem>
        <para>
        Set version keyword to "Id" for the new file(s):
        </para>
        <para>
        <prompt>$</prompt>
        <userinput>svn propset svn:keywords Id new_file</userinput>
        </para>
        </listitem>
        <listitem>
        <para>
        Commit your changes, including the added file(s).
        </para>
        <para>
        <prompt>$</prompt>
        <userinput>svn commit new_file other_files_you_modified</userinput>
        </para>
        </listitem>
        </orderedlist>
        Don't forget a brief description of the reason for the commit so other
        developers don't need to read the diff in order to know what has changed.
        </para>
  </section>
  <section id="ChSrcBinary">
        <title>Binary packaging</title>
        <para>
        Delivering binary packages makes it much easier for the end-users to
        install Wireshark on their target system. This section will explain how
        the binary packages are made.
        </para>

        <section id="ChSrcDeb">
        <title>Debian: .deb packages</title>
        <para>
        The Debian Package is built using dpkg-buildpackage, based on information
        found in the source tree under <filename>debian</filename>. See
        <ulink url="http://www.debian-administration.org/articles/336"/> for a
        more in-depth discussion of the build process.
        </para>
        <para>
        In the wireshark directory, type:
        </para>
        <para>
        <prompt>$</prompt> <userinput>make debian-package</userinput>
        </para>
        <para>
        to build the Debian Package.
        </para>
        </section>

        <section id="ChSrcRpm">
        <title>Red Hat: .rpm packages</title>
        <para>
        The RPM is built using rpmbuild (http://www.rpm.org/), which comes as standard on many flavours of Linux, including
        Red Hat and Fedora. The process creates a clean build environment in <filename>packaging/rpm/BUILD</filename> every
        time the RPM is built. The settings controlling the build are in <filename>packaging/rpm/SPECS/wireshark.spec.in</filename>.
        After editing the settings in this file, <filename>./configure</filename> must be run again in the wireshark directory to
        generate the actual specification script.
        </para>
        <warning><title>Warning!</title><para>
        The SPEC file contains settings for the <filename>configure</filename> used to set the RPM build environment. These are
        completely independent of any settings passed to the usual Wireshark <filename>./configure</filename>.  The exception to
        this rule is that the prefix given to <filename>configure</filename> (<userinput>--prefix</userinput>) is passed to
        rpmbuild.</para></warning>
        <para>
        In the wireshark directory, type:
        </para>
        <para>
        <prompt>$</prompt> <userinput>make rpm-package</userinput>
        </para>
        <para>
        to build the RPM and source RPM. Once it is done, there will be a message stating where the built RPM can be found.
        </para>
        <tip><title>Tip!</title>
        <para>Because this does a clean build, as well as constructing the package, this can take quite a long time.</para>
        </tip>
        <tip><title>Tip!</title>
        <para>Building the RPM requires building a source distribution which itself requires the Qt development tools
        <filename>uic</filename> and <filename>moc</filename>.  These can usually be obtained by installing the
        <filename>qt-devel</filename> package.</para>
        </tip>
        </section>

        <section id="ChSrcOSX">
        <title>MAC OS X: .dmg packages</title>
        <para>
        The MAC OS X Package is built using OS X packaging tools, based on information
        found in the source tree under <filename>packaging/macosx</filename>.
        </para>
        <para>
        In the wireshark directory, type:
        </para>
        <para>
        <prompt>$</prompt> <userinput>make osx-package</userinput>
        </para>
        <para>
        to build the MAC OS X Package.
        </para>
        </section>

        <section id="ChSrcNSIS">
        <title>Win32: NSIS .exe installer</title>
        <para>
        The "Nullsoft Install System" is a free installer generator for Win32
        based systems; instructions how to install it can be found in <xref
        linkend="ChToolsNSIS"/>.
        NSIS is script based, you will find the Wireshark installer
        generation script at: <filename>packaging/nsis/wireshark.nsi</filename>.
        </para>
        <para>
        You will probably have to modify the MAKENSIS setting in the
        <filename>config.nmake</filename> file to specify where the NSIS binaries
        are installed.
        </para>
        <para>
        In the wireshark directory, type:
        </para>
        <para>
        <prompt>&gt;</prompt> <userinput>nmake -f makefile.nmake packaging</userinput>
        </para>
        <para>
        to build the installer.
        </para>
        <tip><title>Tip!</title>
        <para>
        Please be patient while the compression is
        done, it will take some time (a few minutes!) even on fast machines.
        </para>
        </tip>
        <para>
        If everything went well, you will now find something like:
        <filename>wireshark-setup-&WiresharkCurrentVersion;.exe</filename> in
        the <filename>packaging/nsis</filename> directory.
        </para>
        </section>

  </section>

</chapter>
<!-- End of WSDG Chapter Sources -->