ircu2/doc/history/overview.u2.9

Hi fellow undernetters,

I forgot if it was requested on routing-com or here, but you won't see me
cross posting, so I did choose 'wastelanders'.

The request was to mail an overview of the changes 2.8 ==> u2.9,
especially for the new Opers, but also as a reminder for others.

The patch file from irc2.8.21.mu3.1 to ircu2.9.17.mu is 446652 bytes.
So you will understand I can't cover every little change.

New commands
------------

/UPING <server.to> [<port>] [<server.from>] [<number of packets>]

Sends <number of packets> (default 5, max 20) size 1024 bytes, from (remote)
server <server.from> (default local server) to <server.to>. The default
port is 7007 and the same on all servers. If a server is down, you can
still use port 7 (echo). Also 2.8 echo's, on port PORTNUM (config.h).
UPING uses udp, you need CN lines (masks as server names are allowed) but
the connection doesn't have to exist already.

/RPING <server.to> [<server.from>] [<Optional remark>]

Sends one 'RPING' message using the irc protocol over an existing link.
It allows to measure the lag of remote links, respons is in ms accuracy.
The <Optional remark> can be used to measure to total pingtime to your
client (like the CTCP PING) or to add a serial number for automation.

/MAP [server.mask]

Shows a map in the layout as Router.

/SETTIME

Only for debugging, isn't needed. (Oper only).

Changed commands
----------------

/CONNECT

No doubt the biggest impact of 2.9 is on connecting:
When the link is physically possible, your /connect ALWAYS succeeds
except when an H: or L: line somewhere on the net forbids it, or when
*after* your connect another connect is done that cause a loop. The only
restriction is that you are not allowed to make deliberately a loop:
you must first squit. Loops only happen when to connects are done
simultaneously and the SERVER messages had not yet time to propagate
over the whole net.
When a connect (manual or automatically) is done for a link that used
to get "server exists", with 2.9 the Ghost is squitted off the net,
making it possible to recover faster from breaks caused by bad links.
If on the other hand a loop occurs because two parts connect at two
points, the servers that detect the server nick collision will squit
the most logical link to break the loop, and only one link. This results
thus in a connected net one way or the other (for this all 2.8 servers need
to be off the net! Till that time the net will connect and then break
at two places, giving more messages then right now with only 2.8).
2.9 servers also notify the Opers (or users with +s) about net.junctions
and net.breaks. It does this even better then Router: A lot faster, always
correct (REAL junctions), and independent of Router: You will also see
them when Router is 'on the other side'.

/TIME

Has changed. Now also shows the system clock / TimeStamp clock offset.

/MODE +b

You only have to be joined, not be chan op anymore.

/MODE <nick> +d

Makes the user 'Deaf'. Needed for the channel registration service.
Channel messages are not routed to a Deaf person decreasing bandwidth use.

/LINKS

Output also shows used protocol for that link.

New numerics
------------

RPL_MAP, RPL_MAPMORE, RPL_MAPEND and RPL_TRACEPING.

Bug fixes
---------

- A handshaking link doesn't pingtime out; That can interfere with
  slow nameserver lookups.

- U: lines (and K: lines) now active directly after a /rehash

- Don't bind() a socket before connect(), thats useless on machines
  with just one ip number (like we all have), and can confuse
  some OS's I found out.

Significant Patches
-------------------

The following patches have been the objective. To realize them I needed to
rewrite and change huge other parts of the code also, because lot of the code
in 2.8 is under great tension of re-re-re-patches.

- Rewrote m_server. Objective:
  = Allow ghosted servers to reconnect (solution "server exists").
  To allow for this:
  - Added a timestamp to SQUIT, this timestamp functions as a label
    which matches the corresponding SERVER (connect).
  - Added a prefix for every message, absolutely necessary to keep track
    of the correct order (direction actually).

- The oci has been added (oper sees invisibles on own server).

- A new NOTE is added, many bugs removed and extremely speeded up due to
  a better interface with the rest of the code.

- The TimeStamp clocks are now automatically synchronized, so a wrong
  system clock isn't a problem anymore.

- Added a Protocol-version and detection. This allows protocol changes
  with a *MUCH* higher backwards compatibility.

- Server now keeps track of the server map. This allowed for /MAP and
  a lot of speed ups (don't have to scan through all clients to find a
  server) but much more important: The disconnect burst could be brought
  back to ONE message (instead of a QUIT for ever single client).
  Apart from decreasing bandwidth use, this was necessary for other
  important protocol changes, and even more to allow important future
  changes that will reduce the connect.burst as well. The most important
  current impact is that it allows SQUIT to travel down stream AND up stream.
  Because directionless messages can loose the order, the timestamp on
  SQUIT was needed to check the validity.

- In the client structure a pointer to the server structure is used
  rather then the full servername, using less memory AND speeding up
  several places because you don't need to lookup the servername
  anymore.

- USER removed from the connect burst (now all in NICK).

Other patches
-------------

- exit_client() is rewritten.
  Added are exit_client_msg() and exit_new_server().
  This has especially impact on the possibilities within the protocol.
  The old exit_client() was clumsy and therefor already used in an incorrect
  way at several places. The kludges around this part of the code made it
  impossible to make any changes without breaking something else. Only after
  the rewrite it was possible to make changes described else where.
  This also allowed to improve the error message handling to the point that
  Opers see *always* the error messages involved with routing (also those
  from remote /connects, delayed errors and squit reasons 'from the other
  side').

- send.c is more or less rewritten. varargs are fixed now and send.c is
  highly optimized for speed (possible because of new internal server map). 

- All useable dog3 code speed ups have been added.
  These include:
  - Added a head pointer in the dyn buffer.
  - several code optimisations
  - continious kill line checking removed (I added the check at
    the place where it belongs: after a /rehash).

- Useable patches from dl:
  - Stop as much as possible flooding from unregistered connections.
  - VERSION and ADMIN available for unregistered users.
  - syslog (if defined) KILLs of local clients.

- Many compile warnings have been removed. Also a special fix for DYNIX to
  make UPING/RPING also work there (needed gettimeofday()).

Package changes
---------------

- The irc client is removed from the package as are several old files with
  incorrect old useless info (Like 'WHATSNEW', ChangeLog that stopped at 1992).
- A Makefile.dist is added.
- Slighty changed doc/Manual
- New doc/NOTE manual
- NO_DEFAULT_INVISIBLE removed; users are always visible by default.
- Last but not least: patchlevel.h is rewritten so any additional patch
  can do the version update itself, without interfering: No need to edit
  this by hand anymore.

Summary
=======

- Less memory usage
- Speeded up code
- Less bandwidth use, especially disconnect burst
- "Server exists" solved
- Error messages concerning (remote) /connects now always visible.
- New tools to do (remote) link testing
- Intelligent and improved SQUIT handling, should stop unwanted breaks.
- squits comments visible everywhere.
- net.junction and net.break notices
- Overall protocol streamlining allowing for future improvements
  of the protocol.

Run