-*- mode: text; -*- $QuaggaId: Format:%an, %ai, %h$ $ Contents: * GUIDELINES FOR HACKING ON QUAGGA * COMPILE-TIME CONDITIONAL CODE * COMMIT MESSAGE * HACKING THE BUILD SYSTEM * RELEASE PROCEDURE * SHARED LIBRARY VERSIONING * RELEASE PROCEDURE * TOOL VERSIONS * SHARED LIBRARY VERSIONING * PATCH SUBMISSION * PATCH APPLICATION * STABLE PLATFORMS AND DAEMONS * IMPORT OR UPDATE VENDOR SPECIFIC ROUTING PROTOCOLS 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. Each file in the Git repository should have a git format-placeholder (like an RCS Id keyword), somewhere very near the top, commented out appropriately for the file type. The placeholder used for Quagga (replacing with $) is: $QuaggaId: Format:%an, %ai, %h $ See line 2 of HACKING for an example; This placeholder string will be expanded out by the 'git archive' commands, wihch is used to generate the tar archives for snapshots and releases. Please document fully the proper use of a new function in the header file in which it is declared. And please consult existing headers for documentation on how to use existing functions. In particular, please consult these header files: lib/log.h logging levels and usage guidance [more to be added] If changing an exported interface, please try to deprecate the interface in an orderly manner. If at all possible, try to retain the old deprecated interface as is, or functionally equivalent. Make a note of when the interface was deprecated and guard the deprecated interface definitions in the header file, ie: /* Deprecated: 20050406 */ #if !defined(QUAGGA_NO_DEPRECATED_INTERFACES) #warning "Using deprecated (interface(s)|function(s))" ... #endif /* QUAGGA_NO_DEPRECATED_INTERFACES */ To ensure that the core Quagga sources do not use the deprecated interfaces (you should update Quagga sources to use new interfaces, if applicable) while allowing external sources to continue to build. Deprecated interfaces should be excised in the next unstable cycle. Note: If you wish, you can test for GCC and use a function marked with the 'deprecated' attribute. However, you must provide the #warning for other compilers. If changing or removing a command definition, *ensure* that you properly deprecate it - use the _DEPRECATED form of the appropriate DEFUN macro. This is *critical*. Even if the command can no longer function, you *must* still implement it as a do-nothing stub. Failure to follow this causes grief for systems administrators. Deprecated commands should be excised in the next unstable cycle. A list of deprecated commands should be collated for each release. See also below regarding SHARED LIBRARY VERSIONING. COMPILE-TIME CONDITIONAL CODE Please think very carefully before making code conditional at compile time, as it increases maintenance burdens and user confusion. In particular, please avoid gratuitious --enable-.... switches to the configure script - typically code should be good enough to be in Quagga, or it shouldn't be there at all. When code must be compile-time conditional, try have the compiler make it conditional rather than the C pre-processor. I.e. this: if (SOME_SYMBOL) frobnicate(); rather than: #ifdef SOME_SYMBOL frobnicate (); #endif /* SOME_SYMBOL */ Note that the former approach requires ensuring that SOME_SYMBOL will be defined (watch your AC_DEFINEs). COMMIT MESSAGES The commit message should provide: * A suitable one-line summary as the very first line of the message, in the form: [topic] high-level, one line summary Where topic may be name of a subdirectory, and/or daemon. * An optional introduction, discussing the general intent of the change. * a short description of each change made, preferably: * file by file * function by function (use of "ditto", or globs is allowed) to provide a short description of the general intent of the patch. The reason for such itemised commit messages is to encourage the author to self-review every line of the patch, as well as provide reviewers an index of which changes are intended, along with a short description for each. An example (where the general discussion is obviously somewhat redundant, given the one-line summary): [zebra] Enhance frob FSM to detect loss of frob * (general) Add a new DOWN state to the frob state machine to allow the barinator to detect loss of frob. * frob.h: (struct frob) Add DOWN state flag. * frob.c: (frob_change) set/clear DOWN appropriately on state change. * bar.c: (barinate) Check frob for DOWN state. HACKING THE BUILD SYSTEM If you change or add to the build system (configure.ac, any Makefile.am, etc.), try to check that the following things still work: - make dist - resulting dist tarball builds - out-of-tree builds The quagga.net site relies on make dist to work to generate snapshots. It must work. Common problems are to forget to have some additional file included in the dist, or to have a make rule refer to a source file without using the srcdir variable. RELEASE PROCEDURE * Tag the apppropriate commit with a release tag (follow existing conventions). [This enables recreating the release, and is just good CM practice.] * Create a fresh tar archive of the quagga.net repository, and do a test build: git-clone git:///code.quagga.net/quagga.git quagga git-archive --remote=git://code.quagga.net/quagga.git \ --prefix=quagga-release/ master | tar -xf - cd quagga-release ./update-autotools ./configure make make dist The tarball which 'make dist' creates is the tarball to be released! The git-archive step ensures you're working with code corresponding to that in the official repository, and also carries out keyword expansion. If any errors occur, move tags as needed and start over from the fresh checkouts. Do not append to tarballs, as this has produced non-standards-conforming tarballs in the past. [TODO: collation of a list of deprecated commands. Possibly can be scripted to extract from vtysh/vtysh_cmd.c] TOOL VERSIONS Require versions of support tools are listed in INSTALL.quagga.txt. Required versions should only be done with due deliberation, as it can cause environments to no longer be able to compile quagga. 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 'master' branch of the quagga.git repository, in unified diff format, preferably with the '-p' argument to show C function affected by any chunk, and with the -w and -b arguments to minimise changes. E.g: git diff -u -p -w -b mybranch..remotes/quagga.net/master Or by using git-format-patch. * Not doing so is a definite hindrance to patch application. * Include NEWS entries as appropriate. * Please, please include an appropriate commit message with any emailed patches. Doing so makes it easier to review a patch, and apply it. * Include only one semantic change or group of changes per patch. * 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 * Only apply patches that meet the submission guidelines. * If the patch might break something, issue a call for testing on the mailinglist. * Give an appropriate commit message (see above), and use the --author argument to git-commit, if required, to ensure proper attribution (you should still be listed as committer) * Immediately after commiting, double-check (with git-log and/or gitk). If there's a small mistake you can easily fix it with 'git commit --amend ..' * 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) Solaris (strict alignment, any platform) [future: NetBSD/sparc64] The list of daemons that are thought to be stable and that should be tested are: zebra bgpd ripd ospfd ripngd Daemons which are in a testing phase are ospf6d isisd watchquagga 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/) To import code from further sources, e.g. for archival purposes without necessarily having to review and/or fix some changeset, create a branch from 'master': git checkout -b archive/foo master git commit -a "Joe Bar " git push quagga archive/foo presuming 'quagga' corresponds to a file in your .git/remotes with configuration for the appropriate Quagga.net repository.