HACKING

-*- mode: text; -*-

$Id: HACKING,v 1.8 2004/09/01 20:13:23 hasso Exp $

GUIDELINES FOR HACKING ON QUAGGA

[this is a draft in progress]

GNU coding standards apply.  Indentation follows the result of
invoking GNU indent (as of 2.2.8a) with no arguments.  Note that this
uses tabs instead of spaces where possible for leading whitespace, and
assumes that tabs are every 8 columns.  Do not attempt to redefine the
location of tab stops.  Note also that some indentation does not
follow GNU style.  This is a historical accident, and we generally
only clean up whitespace when code is unmaintainable due to whitespace
issues, as fewer changes from zebra lead to easier merges.

For GNU emacs, use indentation style "gnu".

For Vim, use the following lines (note that tabs are at 8, and that
softtabstop sets the indentation level):

set tabstop=8
set softtabstop=2
set shiftwidth=2
set noexpandtab

Be particularly careful not to break platforms/protocols that you
cannot test.

New code should have good comments, and changes to existing code
should in many cases upgrade the comments when necessary for a
reviewer to conclude that the change has no unintended consequences.

CHANGELOG

Add a ChangeLog entry whenever changing code, except for minor fixes
to a commit (with a ChangeLog entry) within the last few days.

There is at present a mixed style for ChangeLog, with some changes
being described in per-directory ChangeLog files, and some at top
level.

[TBD: resolve per-dir vs top-level, perhaps by reading GNU coding
standards]

SHARED LIBRARY VERSIONING

[this section is at the moment just gdt's opinion]

Quagga builds several shared libaries (lib/libzebra, ospfd/libospf,
ospfclient/libsopfapiclient).  These may be used by external programs,
e.g. a new routing protocol that works with the zebra daemon, or
ospfapi clients.  The libtool info pages (node Versioning) explain
when major and minor version numbers should be changed.  These values
are set in Makefile.am near the definition of the library.  If you
make a change that requires changing the shared library version,
please update Makefile.am.

libospf exports far more than it should, and is needed by ospfapi
clients.  Only bump libospf for changes to functions for which it is
reasonable for a user of ospfapi to call, and please err on the side
of not bumping.

There is no support intended for installing part of zebra.  The core
library libzebra and the included daemons should always be built and
installed together.

PATCH SUBMISSION

* Send a clean diff against the head of CVS in unified diff format, eg by:
  cvs <cvs opts> diff -uwb ....

* Include ChangeLog and NEWS entries as appropriate before the patch
  (or in it if you are 100% up to date).

* Inclue only one semantic change or group of changes per patch.p

* Do not make gratuitous changes to whitespace. See the w and b arguments
  to diff.

* State on which platforms and with what daemons the patch has been
  tested.  Understand that if the set of testing locations is small,
  and the patch might have unforeseen or hard to fix consequences that
  there may be a call for testers on quagga-dev, and that the patch
  may be blocked until test results appear.

  If there are no users for a platform on quagga-dev who are able and
  willing to verify -current occasionally, that platform may be
  dropped from the "should be checked" list.

PATCH APPLICATION TO CVS

* Only apply patches that meet the submission guidelines.

* If a patch is large (perhaps more than 100 new/changed lines), tag
  the repository before and after the change with e.g. before-foo-fix
  and after-foo-fix.

* If the patch might break something, issue a call for testing on the
  mailinglist.

* Give an appropriate commit message, eg the ChangeLog entry should suffice,
  if it does not, then the ChangeLog entry itself needs to be corrected.

* By committing a patch, you are responsible for fixing problems
  resulting from it (or backing it out).

STABLE PLATFORMS AND DAEMONS

The list of platforms that should be tested follow.  This is a list
derived from what quagga is thought to run on and for which
maintainers can test or there are people on quagga-dev who are able
and willing to verify that -current does or does not work correctly.

  BSD (Free, Net or Open, any platform) # without capabilities
  GNU/Linux (any distribution, i386)
  [future: some 64-bit machine, e.g. NetBSD/sparc64]
  [Solaris? (could address 64-bit issue)]

The list of daemons that are thought to be stable and that should be
tested are:

  zebra
  bgpd
  ripd
  ospfd
  ripngd

IMPORT OR UPDATE VENDOR SPECIFIC ROUTING PROTOCOLS

The source code of Quagga is based on two vendors:

   zebra_org (http://www.zebra.org/)
   isisd_sf (http://isisd.sf.net/)

In order to import source code, the following procedure should be used:

* Tag the Current Quagga CVS repository:

    cvs tag import_isisd_sf_20031223

* Import the source code into the Quagga's framework. You must not modified
  this source code. It will be merged later.

    cd dir_isisd
    export CVSROOT=:pserver:LOGIN@anoncvs.quagga.net:/var/cvsroot 
    cvs import quagga/isisd isisd_sf isisd_sf_20031223
  ---COMMENTS---
    Vendor: [isisd_sf] Sampo's ISISd from Sourceforge
    Tag: [isisd_sf_20031217] Current CVS release
  ---

* Update your Quagga's directory:

    cd dir_quagga
    cvs update -dP

  or

    cvs co -d quagga_isisd quagga

* Merge the code, then commit:

    cvs commit