This is a rough and informal list of suggested improvements to INN, parts
of INN that need work, and other tasks yet undone.  Some of these may be
in progress, in which case the person working on them will be noted in
square brackets and should be contacted if you want to help.  Otherwise,
let <inn-workers@lists.isc.org> know if you'd like to work on any item listed
below.

This list is currently being migrated to INN's issue tracking system
<https://inn.eyrie.org/trac/>.

The list is divided into changes already tentatively scheduled for a
particular release, higher priority changes that will hopefully be done in
the near future, small or medium-scale projects for the future, and
long-term, large-scale problems.  Note that just because a particular
feature is scheduled for a later release doesn't mean it can't be
completed earlier if someone decides to take it on.  The association of
features with releases is intended to be a rough guide for prioritization
and a set of milestones to use to judge when a new major release is
justified.

Also, one major thing that is *always* welcome is additions to the test
suite, which is currently very minimal.  Any work done on the test suite
to allow more portions of INN to be automatically tested will make all
changes easier and will be *greatly* appreciated.

Last modified $Id: TODO 9825 2015-04-20 17:26:55Z iulius $.


Scheduled for INN 2.6

* Rework and clean up the overview API.  The major change is that the
  initialization function should return a pointer to an opaque struct
  which stores all of the state of the overview subsystem, rather than all
  of that being stored in static variables, and then all other functions
  should take that pointer.  [The new API is available in CURRENT and
  conversion of portions of INN to use it is in progress.  Once that
  conversion is done, the old API can be dropped and the overview backends
  converted to speak the new API at all levels.]

* The TLS layer in nnrpd badly needs to be rewritten.  Currently, it
  doesn't handle timeouts and the code could be cleaned up considerably.
  Support for GnuTLS would also be nice, as would client support.

* Convert readers.conf and storage.conf (and related configuration files)
  to use the new parsing system and break out program-specific sections
  of inn.conf into their own groups.

* The current WIP cache and history cache should be integrated into the
  history API, things like message ID hashing should become a selectable
  property of the history file, and the history API should support
  multiple backend storage formats and automatically select the right one
  for an existing history file based on stored metainformation.

* The interface to embedded filters needs to be reworked.  The information
  about which filters are enabled should be isolated in the filtering API,
  and there should be standard API calls for filtering message IDs, remote
  posts, and local posts.  As part of this revision, all of the Perl
  callbacks should be defined before any of the user code is loaded, and
  the Perl loading code needs considerable cleanup.  At the same time as
  this is done, the implementation should really be documented; we do some
  interesting things with embedded filters and it would be nice to have a
  general document describing how we do it.  [Russ is planning on working
  on this at some point, but won't get upset if someone starts first.]

* All of INN's documentation should be written in POD, with text and man
  pages generated from the POD source.  Anyone is encouraged to work on
  this by just taking any existing documentation in man format and convert
  it to POD while checking that it's still accurate and adding any
  additional useful information that was missed.

* Include the necessary glue so that Perl modules can be added to INN's
  build tree and installed with INN, allowing their capabilities to be
  available to the portions of INN written in Perl.

* Switch nnrpd over to using the new wildmat routines rather than breaking
  apart strings on commas and matching each expression separately.  This
  involves a lot of surgery, since PERMmatch is used all over the place,
  and may change the interpretation of ! and @ in group permission
  wildmats.

* Rework and clean up the storage API.  The major change is that the
  initialization function should return a pointer to an opaque struct
  which stores all of the state of the storage subsystem, rather than all
  of that being stored in static variables, and then all other functions
  should take that pointer.  More of the structures should also be opaque,
  all-caps structure names should be avoided in favor of named structures,
  SMsetup and SMinit should be combined into one function that takes
  flags, SMerrno and SMerrorstr should be replaced with functions that
  return that information, and the wire format utilities should be moved
  into libinn.


Scheduled for INN 2.7

* Add a generic, modular anti-spam and anti-abuse filter, off by default,
  but coming with INN and prominently mentioned in the INSTALL
  documentation.  [Andrew Gierth has work in progress that may be usable
  for this.]

* A unified configuration file combining the facilities of newsfeeds,
  incoming.conf, and innfeed.conf, but hopefully more readable and easier
  for new INN users to edit.  This should have all of the capabilities of
  the existing configuration files, but specifying common things (such as
  file feeds or innfeed feeds) should be very simple and straightforward.
  This configuration file should use the new parsing infrastructure.

* Convert all remaining INN configuration files to the new parsing
  infrastructure.

* INN really should be capable of both sending and receiving a
  headers-only feed (or even an overview-only feed) similar to Diablo and
  using it for the same things that Diablo does, namely clustering,
  pull-on-demand for articles, and the like.  This should be implementable
  as a new backend, although the API may need a few more hooks.  Both a
  straight headers-only feed that only pulls articles down via NNTP from a
  remote server and a caching feed where some articles are pre-fed, some
  articles are pulled down at first read, and some articles are never
  stored locally should be possible.  [A patch for a header-only feed
  from innfeed is included in ticket #17.]

* The libinn, libstorage, and other library interfaces should be treated
  as stable libraries and properly versioned using libtool's
  recommendation for library versioning when changes are made so that they
  can be installed as shared libraries and work properly through releases
  of INN.  This is currently waiting on a systematic review of the
  interface and removal of things that we don't want to support long-term.

* The include files necessary to use libinn, libstorage, and other
  libraries should be installed in a suitable directory so that other
  programs can link against them.  All such include files should be under
  include/inn and included with <inn/header.h>.  All such include files
  should only depend on other inn/* header files and not on, e.g.,
  config.h.  All such include files should be careful about namespace to
  avoid conflicts with other include files used by applications.


High Priority Projects

* INN shouldn't flush all feeds (particularly all program feeds) on
  newgroup or rmgroup.  Currently it reloads newsfeeds to reparse all of
  the wildmat patterns and rebuild the peer lists associated with the
  active file on group changes, and this forces a flush of all feeds.
  The best fix is probably to stash the wildmat pattern (and flags) for
  each peer when newsfeeds is read and then just using the stashed copy on
  newgroup or rmgroup, since otherwise the newsfeeds loading code would
  need significant modification.  But in general, innd is too
  reload-happy; it should be better at making incremental changes without
  reloading everything.

* Add authenticated Path support, based on USEPRO (RFC 5537).
  [Andrew Gierth wrote a patch for part of this a while back, which
  is included in ticket #19.  Marco d'Itri expressed some interest in
  working on this.]

* Various parts of INN are using write or writev; they should all use
  xwrite or xwritev instead.  Even for writes that are unlikely to ever be
  partial, on some systems system calls aren't restartable and xwrite and
  xwritev properly handle EINTR returns.

* Apparently on Solaris open can also be interrupted by a signal; we may
  need to have an xopen wrapper that checks for EINTR and retries.

* tradspool has a few annoying problems.  Deleted newsgroups never have
  their last articles expired, and there is no way of forcibly
  resynchronizing the articles stored on disk with what overview knows
  about unless tradindexed is used.  Some sort of utility program to take
  care of these and to do things like analyze the tradspool.map file
  should be provided.

* contrib/mkbuf and contrib/reset-cnfs.c should be combined into a utility
  for creating and clearing cycbuffs, perhaps combined with cnfsheadconf,
  and the whole thing moved into storage/cnfs rather than frontends (along
  with cnfsstat).  pullart.c may also stand to be merged into the same
  utility (cnfs-util might not be a bad name).

* The Berkeley DB integration of INN needs some improvements in robustness.
  Currently, BerkeleyDB functions can be called by nnrpd out of signal
  handlers and in other unfortunate situations, and coordination between
  nnrpd and innd isn't entirely robust.  Berkeley DB 4.4 offers a new
  DB_REGISTER flag to open to allow for multi-process use of Berkeley DB
  databases and use of that flag should be investigated.


Documentation Projects

* Add man pages for all libinn interfaces.  There should be a subdirectory
  of doc/pod for this since there will be a lot of them; installing them
  as libinn_<section>.3 seems to make the most sense (so, for example,
  error handling routines would be documented in libinn_error.3).

* Better documentation of and support for UUCP feeds.  send-uucp is now
  easier to use, but there's still a paucity of documentation covering the
  whole theory and mechanisms of UUCP feeding.

* Everything installed by INN should have a man page.  Currently, there
  are several binaries and configuration files that don't have man pages.
  (In some cases, the best thing to do with the configuration file may be
  to merge it into another one or find a way to eliminate it.)

* Document the internal formats of the various overview methods, CNFS,
  timehash, and timecaf.  A lot of this documentation already exists in
  various forms, but it needs to be cleaned up and collected in one place
  for each format, preferrably as a man page.

* Add documentation for slave servers.  [Russ has articles from
  inn-workers that can be used as a beginning.]

* Write complete documentation for all of our extensions to RFC 3977 or RFC
  5536 and 5537, preferrably in a format that could be suitable for future
  inclusion into new revisions of the RFCs.

* More comprehensive documentation in texinfo would be interesting; it
  would allow for better organization, separation of specialized topics
  into cleaner chapters, and a significantly better printed manual.  This
  would be a tremendous amount of work, though.


Code Cleanup Projects

* Eliminate everything in the LEGACY section of include/inn/options.h.

* Go over include/inn/options.h and try to eliminate as many of the
  compile-time options there as possible.  They should all be run-time
  options instead if at all possible, maybe in specific sub-sections of
  inn.conf.

* Check to be sure we still need all of the #defines in
  include/inn/paths.h and look at adding anything needed by innfeed (and
  eliminating the separate innfeed header serving the same purpose).

* Use vectors or cvectors everywhere that argify and friends are currently
  used and eliminate the separate implementation in nnrpd/misc.c.

* Break up the remainder of inn/libinn.h into multiple inn/* include files
  for specific functions (such as memory management, wildmat, date handling,
  NNTP commands, etc.), with an inn/util.h header to collect the remaining
  random utilities.  Consider adding some sort of prefix, like inn_, to all
  functions that aren't part of some other logical set with its own prefix.

* Break the CNFS and tradspool code into multiple source files to make it
  easier to understand the logical divisions of the code and consider
  doing the same with the other overview and storage methods.

* The source and bind addresses currently also take "any" or "all"
  wildcards, which can more easily be specified by just not setting them
  at all.  Remove those special strings, modify innupgrade to fix inn.conf
  files using them, and simplify the code.  (It's not completely clear
  that this is the right thing to do.)


Needed Bug Fixes

* Don't require an Xref slave carry all of the groups of its upstream.
  Fixing this will depend on the new overview API (so that overview
  records are stored separately in each group under innd's control) and
  will require ignoring failures to store overview records because the
  group doesn't exist, or checking first to ensure the group exists
  before trying to store the record.

* tradspool currently uses stdio to write out tradspool.map, which can
  cause problems if more than 256 file descriptors are in use for other
  things (such as incoming connections or tradindexed overview cache).
  It should use write() instead.

* LIST NEWSGROUPS should probably only list newsgroups that are marked in
  the active file as valid groups.

* INN's startup script should be sure to clean out old lock files and PID
  files for innfeed.  Be careful, though, since innfeed may still be
  running, spawned from a previous innd.

* makedbz should be more robust in the presence of malformed history
  lines, discarding with them or otherwise dealing with them.

* Some servers reject some IHAVE, TAKETHIS, or CHECK commands with 500
  syntax errors (particularly for long message IDs), and innfeed doesn't
  handle this particularly well at the moment.  It really should have an
  error handler for this case.  [Sven Paulus has a preliminary patch that
  needs testing, included in ticket #26.]

* Editing the active file by hand can currently munge it fairly badly even
  if the server is throttled unless you reload active before restarting
  the server.  This could be avoidable for at least that particular case
  by checking the mtime of active before and after the server was
  throttled.

* innreport silently discards news.notice entries about most of the errors
  innfeed generates.  It should ideally generate some summary, or at least
  note that some error has occurred and the logs should be examined.

* Handling of compressed batches needs to be thoroughly reviewed by
  someone who understands how they're supposed to work.  It's not clear
  that INN_PATH_GZIP is being used correctly at the moment and that
  compressed batch handling will work right now on systems that don't have
  gzip installed (but that do have uncompress).

* innfeed's statistics don't add up properly all the time.  All of the
  article dispositions don't add up to the offered count like they should.
  Some article handling must not be recorded properly.

* If a channel feed exits immediately, innd respawns it immediately,
  causing thrashing of the system and a huge spew of errors in syslog.  It
  should mark the channel as dormant for some period of time before
  respawning it, perhaps only if it's already died multiple times in a
  short interval.

* ctlinnd begin <site-name> was causing innd to core dump.

* Handling of innfeed's dropped batches needs looking at.  There are three
  places where articles can fall between the cracks:  an innfeed.togo file
  written by innd when the feed can't be spawned, a batch file named after
  the feed name which can be created under similar circumstances, and the
  dropped files written by innfeed itself.  procbatch can clean these up,
  but has to be run by hand.

* When using tradspool, groups are not immediately added to tradspool.map
  when created, making innfeed unable to find the articles until after
  some period of time.  Part of the problem here is that tradspool only
  updates tradspool.map on a lazy basis, when it sees an article in that
  group, since there is no storage hook for creation of a new group.

* nntpget doesn't handle long lines in messages.

* WP feeds break if there are spaces in the Path header, and the inn.conf
  parser doesn't check for this case and will allow people to configure
  their server that way.  (It's not clear that the latter is actually a
  bug, given the new USEFOR attempt to allow folding of Path headers, but
  the space needs to be removed for WP feeds.)

* innd returns 437 for articles that were accepted but filed in the junk
  group.  It should probably return the appropriate 2xx status code in
  that case instead.

* SIGPIPE handling in nnrpd calls all sorts of functions that shouldn't be
  called from inside a signal handler.

* Someone should go through the BUGS sections of all of the man pages and
  fix those for which the current behavior is unacceptable.

* The ovdb server utilities don't handle unclean shutdowns very well.
  They may leave PID files sitting around, fail to start properly, and
  otherwise not do what's expected.  This area needs some thought and a
  careful design.

* tdx-util can't fix hash chain loops of length greater than one, and they
  cause both tdx-util -F and innd to hang.

* CNFS is insufficiently robust when corrupt buffers are encountered.
  Setting cnfscheckfudgesize clears up issues that otherwises causes INN
  to crash.

* There should be a way, with the Perl authentication hooks, to either
  immediately return a list of newsgroups one has access to based on the
  hostname or to indicate that authentication is required and make the
  user be prompted with a 480 code when they try to access anything.
  Right now, that doesn't appear to be possible.

* Handling of article rejections needs a lot of cleanup in innd/art.c so
  that one can cleanly indicate whether a given rejection should be
  remembered or not, and the code that does the remembering needs to be
  refactored and shared.  Once this is done, we need to not remember
  rejections for duplicated Xref headers.

* rnews's error handling for non-zero exits by child batch decompressers
  could use some improvement (namely, there should be some).  Otherwise,
  when gzip fails for some reason, we read zero bytes and then throw
  away the batch without realizing we have an error.


Requested New Features

* Consider implementing the HEADERS command as discussed rather
  extensively in news.software.nntp.  HEADERS was intended as a general
  replacement for XHDR and XPAT.  [Greg Andruk has a preliminary patch.]

* There have been a few requests for the ability to programmatically set
  the subject of the report generated by news.daily, with escapes that are
  filled in by the various pieces of information that might be useful.

* A bulk cancel command using the MODE CANCEL interface.  Possibly through
  ctlinnd, although it may be a bit afield of what ctlinnd is currently
  for.

* Sven Paulus's patch for nnrpd volume reports should be integrated.
  [Patch included in ticket #135.]

* Lots of people encrypt Injection-Info in various ways.  Should that be
  offered as a standard option?  The first data element should probably
  remain unencrypted so that the O flag in newsfeeds doesn't break.

  Should there also be an option not to generate Injection-Info?

  Olaf Titz suggests for encryption:

      This can be done by formatting injection fields in a way that they
      are always a multiple of 8 bytes and applying a 64 bit block cipher
      in ECB mode on it (for instance "395109AA000016FF").

* ctlinnd flushlogs currently renames all of the log files.  It would be
  nice to support the method of log rotation that most other daemons
  support, namely to move the logs aside and then tell innd to reopen its
  log files.  Ideally, that behavior would be triggered with a SIGHUP.
  scanlogs would have to be modified to handle this.

  The best way to support this seems to be to leave scanlogs as is by
  default, but also add two additional modes.  One would flush all the
  logs and prepare for the syslog logs to be rotated, and the other would
  do all the work needed after the logs have been rotated.  That way, if
  someone wanted to plug in a separate log rotation handler, they could do
  so and just call scanlogs on either side of it.  The reporting portions
  of scanlogs should be in a separate program.

* Several people have Perl interfaces to pieces of INN that should ideally
  be part of the INN source tree in some fashion.  Greg Andruk has a bunch
  of stuff that Russ has copies of, for example.  [Patches included in
  tickets #133 and #134.]

* There are various available patches for Cancel-Lock and an Internet
  draft; support should be added to INN for both generation and
  verification (definitely optional and not on by default at this point).

* It would be nice to be able to reload inn.conf (although difficult, due
  to the amount of data that's generated from it and stashed in various
  places).

* remembertrash currently rejects and remembers articles with syntax
  errors as well as things like unwanted newsgroups and unwanted
  distributions, which means that if a peer sends you a bunch of mangled
  articles, you'll then also reject the correct versions of the articles
  from other peers.  This should probably be rethought.

* Additional limits for readers.conf:  Limit on concurrent parallel reader
  streams, limit on KB/second download (preliminary support for this is
  already in), and a limit on maximum posted articles per day (tied in
  with the backoff stuff?).  These should be per-IP or per-user, but
  possibly also per-access group.  (Consider pulling the -H, -T, -X, and 
  -i code out from innd and using it here.)

* timecaf should have more configurable parameters (at the least, how
  frequently to switch to a new CAF file should be an option).
  storage.conf should really be extended to allow method-specific
  configuration for things like this (and to allow the cycbuff.conf file
  to be merged into storage.conf).

* Allow generation of arbitrary additional information that could go in
  overview by using embedded Perl or Python code.  This might be a cleaner
  way to do the keywords code, which really wants Perl's regex engine
  ideally.  It would also let one do something like doing MD5 hashes of
  each article and putting that in the overview if you care a lot about
  making sure that articles aren't corrupted.

* Allow some way of accepting articles regardless of the Date header, even
  if it's far into the future.  Some people are running into articles that
  are dated years into the future for some reason that they still want to
  store on the server.

* There was a request to make --program-suffix and the other name
  transformation options to autoconf work.  The standard GNU package does
  this with really ugly sed commands in the Makefile rules; we could
  probably do better, perhaps by substituting the autoconf results into
  support/install-sh.

* INN currently uses hash tables to store the active file internally.  It
  would be worth trying ternary search trees to see if they're faster; the
  data structure is simpler, performance may be comparable for hits and
  significantly better for misses, sizing and resizing becomes a non-issue,
  and the space penalty isn't too bad.  A generic implementation is already
  available in libinn.  (An even better place to use ternary search trees
  may be the configuration parser.)

* Provide an innshellvars equivalent for Python.

* inncheck should check the syntax of all the various files that are
  returned by LIST commands, since having those files present with the
  wrong syntax could result in non-compliant responses from the server.
  Possibly the server should also refuse to send malformatted lines to
  the client.

* ctlinnd reload incoming.conf could return a count of the hosts that
  failed, or even better a list of them.  This would make pruning old
  stuff out of incoming.conf much easier.

* nnrpd could use sendfile(2), if available, to send articles directly
  to the socket (for those storage methods where to-wire conversion is
  not needed).  This would need to be added to the storage API.

* Somebody should look at keeping the "newsgroups" file more accurate
  (e.g. newgroups for existing groups should change description, better
  checkgroups handling, checking for duplicates).

* The by-domain statistics innreport generates for nnrpd count all local
  connections (those with no "." in the hostname) in with the errors as
  just "?".  The host2dom function could be updated to group these as
  something like "Local".

* news.daily could detect if expire segfaults and unpause the server.

* When using SSL, track the amount of data that's been transferred to the
  client and periodically renegotiate the session key.

* When using SSL, use SSL_get_peer to get a verified client certificate,
  if available, and use it to create an additional header line when
  posting articles (X-Auth-Poster?).  This header could use:

      X509_NAME_oneline(X509_get_subject_name(peer),...)

  for the full distinguished name, or

      X509_name_get_text_by_NID(X509_get_subject_name(peer),
                                NID_commonName, ...)
   
  for the client's "common name" alone.

* When using SSL, use the server's key to generate an HMAC of the body of
  the message (and most headers?), then include that digest in the
  headers.  This allows a news administrator to determine if a complaint
  about the content of a message is fraudulent since the message was
  changed after transmission.

* Allow permission for posting cancels to be configured in readers.conf
  in an access block.

* Allow the applicability of auth blocks to be restricted to particular
  username patterns, probably by adding a users: key to the auth block
  that matches similar to hosts:.

* It would be nice to have bindaddress (and bindaddress6) as a peer block
  parameter and not just a global parameter in innfeed.

* Add cnfsstat to innstat.  cnfsstat really needs a more succinct mode
  before doing this, since right now the output can be quite verbose.


General Projects

* All the old packages in unoff-contrib should be reviewed for integration
  into INN.

* It may be better for INN on SysV-derived systems to use poll rather than
  select.  The semantics are better, and on some systems (such as Solaris)
  select is limited to 1024 file descriptors whereas poll can handle any
  number.  Unfortunately, the API is drastically different between the
  two and poll isn't portable, so supporting both cleanly would require a
  bit of thought.

* Currently only innd and innfeed increase their file descriptor limits.
  Other parts of INN, notably makehistory, may benefit from doing the same
  thing if they can without root privileges.

* Revisit support for aliased groups and what nnrpd does with them.
  Should posts to the alias automatically be redirected to the real group?
  Regardless, the error return should provide useful information about
  where to post instead.  Also, the new overview API, for at least some of
  the overview methods, truncated the group status at one character and
  lost the name of the group to which a group is aliased; that needs to be
  fixed.

* More details as to why a message ID is bad would be useful to return to
  the user, particularly for rnews, inews, etc.

* Support putting the history file in different directory from the other
  (much smaller) db files without hand-editing a bunch of files.

* frontends/pullnews and frontends/nntpget should be merged in one script.

* backends/filechan is just a simple version of backends/buffchan.  It
  looks like filechan could just be deleted and innupgrade taught to change
  filechan feeds to buffchan -u feeds.  map.c, which is only used by those
  two programs, could just be included in the same source file.

* actsyncd could stand a rewrite and cleaner handling of both
  configuration and syncing against multiple sources which are canonical
  for different sets of groups.  In the process, FTP handling should
  support debugging.

* send-nntp and nntpsend basically do the same thing; send-nntp could
  probably be removed (possibly with some extra support in nntpsend for
  doing simpler things).


Long-Term Projects

* Look at turning header parsing into a library of some sort.  Lots of INN
  does this, but different parts of INN need subtly different things, so
  the best API is unclear.

* INN's header handling needs to be checked against RFC 5536 and 5537.
  This may want wait until after we have a header parsing library.

* The innd filter should be able to specify additional or replacement
  groups into which an article should be filed, or even spool the article
  to a local disk file rather than storing it.  (See the stuff that the
  nnrpd filter can already do.)

* When articles expire out of a storage method with self-expire
  functionality, the overview and history entries for those articles
  should also be expired immediately.  Otherwise, things like the GROUP
  command don't give the correct results.  This will likely require a
  callback that can be passed to CNFS that is called to do the overview
  and history cleanup for each article overwritten.

* Feed control, namely allowing your peers to set policy on what articles
  you feed them (not just newsgroups but max article size and perhaps even
  filter properties like "non-binary").  Every site does this a bit
  differently.  Some people have web interfaces, some people use GUP, some
  people roll their own alternate things.  It would really be nice to have
  some good way of doing this as part of INN.  It's worth considering an
  NNTP extension for this purpose, although the first step is to build a
  generic interface that an NNTP extension, a web page, etc. could all
  use.  (An alternate way of doing this would be to extend IHAVE to pass
  the list of newsgroups as part of the command, although this doesn't
  seem as generally useful.)

* Traffic classification as an extension of filtering.  The filter should
  be able to label traffic as binary (e.g.) without rejecting it, and
  newsfeeds should be extended to allow feeding only non-binary articles
  (e.g.) to a peer.

* External authenticators should also be able to do things like return a
  list of groups that a person is allowed to read or post to.  Currently,
  maintaining a set of users and a set of groups, each of which some
  subset of the users is allowed to access, is far too difficult.  For a
  good starting list of additional functionality that should be made
  available, look at everything the Perl authentication hooks can do.

* Allow nnrpd to spawn long-running helper processes.  Not only would this
  be useful for handling authentication (so that the auth hooks could work
  without execing a program on every connection), but it may allow for
  other architectures for handling requests (such as a pool of helpers
  that deal only with overview requests).  More than that, nnrpd should
  *be* a long-running helper process that innd can feed open file
  descriptors to.  [Aidan Culley has ideas along these lines.]

* The tradspool storage method requires assigning a number to every
  newsgroup (for use in a token).  Currently this is maintained in a
  separate tradspool.map file, but it would be much better to keep that
  information in the active file where it can't drop out of sync.  A code
  assigned to each newsgroup would be useful for other things as well,
  such as hashing the directories for the tradindexed overview.  For use
  for that purpose, though, the active file would have to be extended to
  include removed groups, since they'd need to be kept in the active file
  to reserve their numbers until the last articles expired.

* The locking of the active file leaves something to be desired; in
  general, the locking in INN (for the active file, the history file,
  spool updates, overview updates, and the like) needs a thorough
  inspection and some cleanup.  A good place to start would be tracing
  through the pause and throttle code and write up a clear description of
  what gets locked where and what is safely restarted and what isn't.
  Long term, there needs to be a library locking routine used by
  *everything* that needs to write to the history file, active file, etc.
  and that keeps track of the PID of the process locking things and is
  accessible via ctlinnd.

* There is a fundamental problem with the current design of the
  control.ctl file.  It combines two things:  A database of hierarchies,
  their maintainers, and related information, and a list of which
  hierarchies the local server should honor.  These should be separated
  out into the database (which could mostly be updated from a remote
  source like ftp.isc.org and then combined with local additions) and a
  configured list of hierarchies (or sub-hierarchies within hierarchies)
  that control messages should be honored for.  This should be reasonably
  simple although correct handling of checkgroups could get a mite tricky.

* Possible NNTP extension:  Compression of the protocol, using gzip,
  bzip2, or some other technique.  Particularly useful for long lists like
  the active file information or the overview information, but possibly
  useful in general for other things.

* Install wizards.  Configuring INN is currently very complex even for an
  experienced news admin, and there are several fairly standard
  configurations that shouldn't be nearly that complicated to get running
  out of the box.  A little interactive Perl script asking some simple
  questions could probably get a lot of cases easily right.

* One ideally wants to be able to easily convert between different
  overview formats or storage methods, refiling articles in place.  This
  should be possible once we have a history API that allows changing the
  storage location of an article in-place.

* Set up the infrastructure required so that INN can use alloca.  This
  would significantly decrease the number of calls to malloc needed and
  would be a lot more convenient.  alloca is now available, but most
  programs still need to call alloca_free in their main loops before we
  can use it in the various libraries.

* Support building in a separate directory than the source tree.  It may
  be best to just support this via lndir rather than try to do it in
  configure, but it would be ideal to add support for this to the autoconf
  system.  Unfortunately, the standard method requires letting configure
  generate all of the makefiles, which would make running configure and
  config.status take much longer than it does currently.

* Look at adding some kind of support for MODE CANCEL via network sockets
  and fixing up the protocol so that it could possibly be standardized
  (the easiest thing to do would probably be to change it into a CANCEL
  command).  If we want to get to the point where INN can accept and even
  propagate such feeds from dedicated spam filters or the like, there must
  also be some mechanism of negotiating policy in order to decide what
  cancels the server wants to be fed.

* The "possibly signed" char data type is one of the inherent flaws of C.
  Some other projects have successfully gotten completely away from this
  by declaring all of their strings to be unsigned char, defining a macro
  like U that casts strings to unsigned char for use with literal strings,
  and always using unsigned char everywhere.  Unfortunately, this also
  requires wrappering all of the standard libc string functions, since
  they're prototyped as taking char rather than unsigned char.  The
  benefits include cleaner and consistent handling of characters over 127,
  better warnings from the compiler, consistent behavior across platforms
  with different notions about the signedness of char, and the elimination
  of warnings from the <ctype.h> macros on platforms like Solaris where
  those macros can't handle signed characters.  We should look at doing
  this for INN.

* It would clean up a lot of code considerably if we could just use mmap
  semantics regardless of whether the system has mmap.  It may be possible
  to emulate mmap on systems that don't have it by reading the entirety of
  the file into memory and setting the flags that require things to call
  mmap_flush and mmap_invalidate on a regular basis, but it's not clear
  where to stash the file descriptor that corresponds to the mapped file.

* Consider replacing the awkward access: parameter in readers.conf with
  separate commands (e.g. "allow_newnews: true") or otherwise cleaning up
  the interaction between access: and read:/post:.  Note that at least
  allownewnews: can be treated as a setting for overriding inn.conf and
  should be very easy to add.

* Add a localport: parameter (similar to localaddress:) to readers.conf
  auth groups.  With those two parameters (and ssl_required:) we
  essentially eliminate the need to run multiple instances of nnrpd just to
  use different configurations.

* Various things may break when trying to use data written while compiled
  with large file support using a server that wasn't so compiled (and vice
  versa).  The main one is the history file, but tradindexed is also
  affected and buffindexed has been reported to have problems with this
  as well.  Ideally, all of INN's data files should be as portable as
  possible.


Code Reorganization

* storage should be reserved just for article storage; the overview
  methods should be in a separate overview tree.

* The split between frontends and backends is highly non-intuitive.  Some
  better organization scheme should be arrived at.  Perhaps something
  related to incoming and outgoing, with programs like cnfsstat moved into
  the storage directory with the other storage-related code?

* Add a separate utils directory for things like convdate, shlock,
  shrinkfile, and the like.  Some of the scripts may possibly want to go
  into that directory too.

* The lib directory possibly should be split so that it contains only code
  always compiled and part of INN, and the various replacements for
  possibly missing system routines are in a separate directory (such as
  replace).  These should possibly be separate libraries; there are things
  that currently link against libinn that only need the portability
  pieces.

* The doc directory really should be broken down further by type of
  documentation or section or something; it's getting a bit unwieldy.

* Untabify and reformat all of the code according to a consistent coding
  style which would then be enforced for all future check-ins.
