HACKING

   1 -*- mode: text; -*-
   2 $Id: HACKING,v 1.20 2005/04/25 00:37:03 paul Exp $
   3
   4 GUIDELINES FOR HACKING ON QUAGGA
   5
   6 [this is a draft in progress]
   7
   8 GNU coding standards apply.  Indentation follows the result of
   9 invoking GNU indent (as of 2.2.8a) with no arguments.  Note that this
  10 uses tabs instead of spaces where possible for leading whitespace, and
  11 assumes that tabs are every 8 columns.  Do not attempt to redefine the
  12 location of tab stops.  Note also that some indentation does not
  13 follow GNU style.  This is a historical accident, and we generally
  14 only clean up whitespace when code is unmaintainable due to whitespace
  15 issues, as fewer changes from zebra lead to easier merges.
  16
  17 For GNU emacs, use indentation style "gnu".
  18
  19 For Vim, use the following lines (note that tabs are at 8, and that
  20 softtabstop sets the indentation level):
  21
  22 set tabstop=8
  23 set softtabstop=2
  24 set shiftwidth=2
  25 set noexpandtab
  26
  27 Be particularly careful not to break platforms/protocols that you
  28 cannot test.
  29
  30 New code should have good comments, and changes to existing code
  31 should in many cases upgrade the comments when necessary for a
  32 reviewer to conclude that the change has no unintended consequences.
  33
  34 Each file in CVS should have the RCS keyword Id, somewhere very near
  35 the top, commented out appropriately for the file type.  Just add
  36 <dollar>Id:<dollar>, replacing <dollar> with $.  See line 2 of HACKING
  37 for an example; on checkout :$ is expanded to include the value.
  38
  39 Please document fully the proper use of a new function in the header file
  40 in which it is declared.  And please consult existing headers for
  41 documentation on how to use existing functions.  In particular, please consult
  42 these header files:
  43
  44   lib/log.h     logging levels and usage guidance
  45   [more to be added]
  46
  47 If changing an exported interface, please try to deprecate the interface in
  48 an orderly manner. If at all possible, try to retain the old deprecated
  49 interface as is, or functionally equivalent. Make a note of when the
  50 interface was deprecated and guard the deprecated interface definitions in
  51 the header file, ie:
  52
  53 /* Deprecated: 20050406 */
  54 #if !defined(QUAGGA_NO_DEPRECATED_INTERFACES)
  55 #warning "Using deprecated <libname> (interface(s)|function(s))"
  56 ...
  57 #endif /* QUAGGA_NO_DEPRECATED_INTERFACES */
  58
  59 To ensure that the core Quagga sources do not use the deprecated interfaces
  60 (you should update Quagga sources to use new interfaces, if applicable)
  61 while allowing external sources to continue to build. Deprecated interfaces
  62 should be excised in the next unstable cycle.
  63
  64 Note: If you wish, you can test for GCC and use a function
  65 marked with the 'deprecated' attribute. However, you must provide the
  66 #warning for other compilers.
  67
  68 If changing or removing a command definition, *ensure* that you properly
  69 deprecate it - use the _DEPRECATED form of the appropriate DEFUN macro. This
  70 is *critical*. Even if the command can no longer function, you *must* still
  71 implement it as a do-nothing stub. Failure to follow this causes grief for
  72 systems administrators. Deprecated commands should be excised in the next
  73 unstable cycle. A list of deprecated commands should be collated for each
  74 release.
  75
  76 See also below regarding SHARED LIBRARY VERSIONING.
  77
  78
  79 CHANGELOG
  80
  81 Add a ChangeLog entry whenever changing code, except for minor fixes
  82 to a commit (with a ChangeLog entry) within the last few days.
  83
  84 Most directories have a ChangeLog file; changes to code in that
  85 directory should go in the per-directory ChangeLog.  Global or
  86 structural changes should also be mentioned in the top-level
  87 ChangeLog.
  88
  89 Certain directories do not contain project code, but contain project
  90 meta-data, eg packaging information, changes to files in these directory may
  91 not require the global ChangeLog to be updated (at the discretion of the
  92 maintainer who usually maintains that meta-data). Also, CVS meta-data such
  93 as cvsignore files do not require ChangeLog updates, just a sane commit
  94 message.
  95
  96
  97 HACKING THE BUILD SYSTEM
  98
  99 If you change or add to the build system (configure.ac, any Makefile.am,
 100 etc.), try to check that the following things still work:
 101
 102         - make dist
 103         - resulting dist tarball builds
 104         - out-of-tree builds
 105
 106 The quagga.net site relies on make dist to work to generate snapshots. It
 107 must work. Commong problems are to forget to have some additional file
 108 included in the dist, or to have a make rule refer to a source file without
 109 using the srcdir variable.
 110
 111 RELEASE PROCEDURE
 112
 113   Tag the repository with release tag (follow existing conventions).
 114   [This enables recreating the release, and is just good CM practice.]
 115
 116   Check out the tag, and do a test build.
 117
 118   In an empty directory, do a fresh checkout with -r <release-tag>
 119   [This makes the dates in the tarball be the modified dates in CVS.]
 120
 121   ./configure
 122   make dist
 123
 124 If any errors occur, move tags as needed and start over from the fresh
 125 checkouts.  Do not append to tarballs, as this has produced
 126 non-standards-conforming tarballs in the past.
 127
 128 [TODO: collation of a list of deprecated commands. Possibly can be scripted
 129 to extract from vtysh/vtysh_cmd.c]
 130
 131
 132 TOOL VERSIONS
 133
 134 Require versions of support tools are listed in INSTALL.quagga.txt.
 135 Required versions should only be done with due deliberation, as it can
 136 cause environments to no longer be able to compile quagga.
 137
 138
 139 SHARED LIBRARY VERSIONING
 140
 141 [this section is at the moment just gdt's opinion]
 142
 143 Quagga builds several shared libaries (lib/libzebra, ospfd/libospf,
 144 ospfclient/libsopfapiclient).  These may be used by external programs,
 145 e.g. a new routing protocol that works with the zebra daemon, or
 146 ospfapi clients.  The libtool info pages (node Versioning) explain
 147 when major and minor version numbers should be changed.  These values
 148 are set in Makefile.am near the definition of the library.  If you
 149 make a change that requires changing the shared library version,
 150 please update Makefile.am.
 151
 152 libospf exports far more than it should, and is needed by ospfapi
 153 clients.  Only bump libospf for changes to functions for which it is
 154 reasonable for a user of ospfapi to call, and please err on the side
 155 of not bumping.
 156
 157 There is no support intended for installing part of zebra.  The core
 158 library libzebra and the included daemons should always be built and
 159 installed together.
 160
 161
 162 PATCH SUBMISSION
 163
 164 * Send a clean diff against the head of CVS in unified diff format, eg by:
 165   cvs <cvs opts> diff -upwb ....
 166
 167 * Include ChangeLog and NEWS entries as appropriate before the patch
 168   (or in it if you are 100% up to date). A good ChangeLog makes it easier to
 169   review a patch, hence failure to include a good ChangeLog is prejudicial
 170   to proper review of the patch, and hence the possibility of inclusion.
 171
 172 * Include only one semantic change or group of changes per patch.
 173
 174 * Do not make gratuitous changes to whitespace. See the w and b arguments
 175   to diff.
 176
 177 * State on which platforms and with what daemons the patch has been
 178   tested.  Understand that if the set of testing locations is small,
 179   and the patch might have unforeseen or hard to fix consequences that
 180   there may be a call for testers on quagga-dev, and that the patch
 181   may be blocked until test results appear.
 182
 183   If there are no users for a platform on quagga-dev who are able and
 184   willing to verify -current occasionally, that platform may be
 185   dropped from the "should be checked" list.
 186
 187
 188 PATCH APPLICATION TO CVS
 189
 190 * Only apply patches that meet the submission guidelines.
 191
 192 * If a patch is large (perhaps more than 100 new/changed lines), tag
 193   the repository before and after the change with e.g. before-foo-fix
 194   and after-foo-fix.
 195
 196 * If the patch might break something, issue a call for testing on the
 197   mailinglist.
 198
 199 * Give an appropriate commit message, eg the ChangeLog entry should suffice,
 200   if it does not, then the ChangeLog entry itself needs to be corrected. The
 201   commit message text should be identical to that added to the ChangeLog
 202   message. (One suggestion: when commiting, use your editor to read in the
 203   ChangeLog and delete all previous ChangeLogs.)
 204
 205 * By committing a patch, you are responsible for fixing problems
 206   resulting from it (or backing it out).
 207
 208
 209 STABLE PLATFORMS AND DAEMONS
 210
 211 The list of platforms that should be tested follow.  This is a list
 212 derived from what quagga is thought to run on and for which
 213 maintainers can test or there are people on quagga-dev who are able
 214 and willing to verify that -current does or does not work correctly.
 215
 216   BSD (Free, Net or Open, any platform) # without capabilities
 217   GNU/Linux (any distribution, i386)
 218   Solaris (strict alignment, any platform)
 219   [future: NetBSD/sparc64]
 220
 221 The list of daemons that are thought to be stable and that should be
 222 tested are:
 223
 224   zebra
 225   bgpd
 226   ripd
 227   ospfd
 228   ripngd
 229
 230 Daemons which are in a testing phase are
 231
 232   ospf6d
 233   isisd
 234   watchquagga
 235
 236
 237 IMPORT OR UPDATE VENDOR SPECIFIC ROUTING PROTOCOLS
 238
 239 The source code of Quagga is based on two vendors:
 240
 241    zebra_org (http://www.zebra.org/)
 242    isisd_sf (http://isisd.sf.net/)
 243
 244 [20041105: Is isisd.sf.netf still where isisd word is happening, or is
 245 the quagga repo now the canonical place?  The last tarball on sf is
 246 two years old.  --gdt]
 247
 248 In order to import source code, the following procedure should be used:
 249
 250 * Tag the Current Quagga CVS repository:
 251
 252     cvs tag import_isisd_sf_20031223
 253
 254 * Import the source code into the Quagga's framework. You must not modified
 255   this source code. It will be merged later.
 256
 257     cd dir_isisd
 258     export CVSROOT=:pserver:LOGIN@anoncvs.quagga.net:/var/cvsroot
 259     cvs import quagga/isisd isisd_sf isisd_sf_20031223
 260   ---COMMENTS---
 261     Vendor: [isisd_sf] Sampo's ISISd from Sourceforge
 262     Tag: [isisd_sf_20031217] Current CVS release
 263   ---
 264
 265 * Update your Quagga's directory:
 266
 267     cd dir_quagga
 268     cvs update -dP
 269
 270   or
 271
 272     cvs co -d quagga_isisd quagga
 273
 274 * Merge the code, then commit:
 275
 276     cvs commit
 277