040706	Servers can be assigned different weights to account for
	differing capacity. New -W command-line option. New penctl
	commands:
	server S weight W	(assign weight to server)
	weight			(use weight for server selection)
	no weight		(do not use weight for server selection)

	Cleaned up the logic in add_client so the weighted server
	selection can be used without client tracking.

	Released 0.15.0.

040624	Some performance enhancing changes:

	New variable connections_used remembers the number of used
	slots in conns[]. It is incremented by store_conn and
	decremented by close_conn. This allows the main loop to
	only accept new connections if there are empty slots in
	conns[], which is much better than accepting the connection
	only to immediately close it because we can't handle it.

	New variable connections_last remembers the last used slot
	in conns[]. This allows us to scan for empty slots much faster
	in store_conn when there are many simultaneous connections.

	Released 0.14.0.

040622	Documented the procedure to change FD_SETSIZE on Linux
	in INSTALL.

040604	Documented the include command in the penctl manpage.

040527	Fixed SSL so it works in nonblocking mode, except that
	it doesn't work anyway.
	Moved listenfd and ctrlfd out of main.

040428	Highly experimental SSL code in pen.c. Updated manpage
	with the new options. Added https example to HOWTO.
	Released 0.13.0.

040403	Replaced signal with sigaction so connect() to nonexisting
	servers can be interrupted and not restarted.
	Released 0.12.3.

040318	Bugfix by Andreas Wrede: Running pen with -H to generate
	X-Forwarded-For headers causes POST request data sections
	to be dropped, if they are in the same packet as the POST
	header (rather than a continuation packet) and the if the
	POST data contains binary zeros.  This is almost always the
	case with Internet Explorer 6.  Mozilla and friends send
	the data of a POST request in a separate packet, so the
	problem does not show up there.

040310	Changed setlinebuf to setvbuf in penlogd.c
	Released 0.12.2.

040201	Bugfix: rewrite_request would only add the X-Forwarded-For
	header for the first request.
	Released 0.12.1.

040104	Removed the reference to mergelogs from the README and
	added one to penlogd instead.

031023	Released 0.12.0.

031022	Penlogd: sscanf would read 100 bytes + terminating nul into
	a buffer of size 100. Now reads 99+nul. Spotted by Oezguer Kesim.

031021	Let tracking time be set through penctl.cgi.
	In do_cmd, "no log": only close the logfile if it is open.
	New penctl command, "write [FILE]" writes current configuration
	to a file. If FILE is omitted, overwrite the original
	configuration file (-F option).

031017	Pen: Time based expiration of tracked clients. Default is
	0 seconds = never expire. Added -T option to control expiry
	time. Also added penctl command "tracking N".
	Penlogd: zero-terminate results from recvfrom.

031013	In penlogd.c: don't complain if recvfrom is interrupted by signal.

031013	Released 0.11.1.

031011	Use sigaction rather than signal in penlogd.
	Check for inet_aton in libresolv (needed for Solaris).
	Install documentation into ${prefix}/doc/pen (can be
	changed using the --with-doc= configuration option).
	Added tgz target to Makefile.am for Slackware packaging.

030922	Added an "include" keyword to the command interface, so the
	configuration can be split into several files.
	Added access control lists, numbered 0 to 9. The command
	syntax to define them are:
	acl N permit|deny ipaddress mask	create acl
	no acl N				delete acl
	client_acl N			bind clients to acl
	control_acl N			bind control interface to acl
	server S acl N			who can use server S
	All access lists start out empty, defaulting to permit anything.

030910	In rewrite_request: don't add an X-Forwarded-For: if there
	already is one.

030906	Added a configuration file (-F option) with commands in
	penctl format. It is read after processing all command line
	arguments and also when a HUP signal is received.

030905	Updated pen manpage to reflect the new -X and -S options.
	In rewrite_request: look for \n\n if we can't find
	\r\n\r\n. Some clients do that, according to
	Steve Hall <steveh@intrapower.com.au>.
	Moved everything from CONTROL into penctl.1.
	Also added the exit command to penctl.1.

030905	Released 0.10.3.

030904	Preallocate slots for servers that can be dynamically added
	and removed using the control interface, up to a maximum
	number determined by the -S option (default 16).

030821	A patch from Anders Nordby <anders@fix.no> sets the group
	as well as user id when running pen with the -u option.

030821	Released 0.10.2.

030820	A patch from Mikko Ruuska <mikko.ruuska@solidtech.com> adds
	an exit command to pen's control port interface.

030820	Patch for pen.c by Andreas Wrede <andreas@planix.com>, fixing
	the following bugs:

	The message indicating a failed server is re-issued on every attempt,
	due to a inverted if-test.

	The attached patch issues the messages only the first time a server
	fails and it shows when we will retry the connection. It also
	suppresses multiple "Using emergency server" messages.

030820	#include <string.h> in penlog.c.

030820	Patch for penlogd.c by Branson Matheson <branson@windborne.net>:
	  - pen sends two lines for every log.. penlogd only needs one 
	        to function. 
	  - added a -b ... unbuffer to the opts for penlogd so that you 
	        can actually see the lines as they come out.
	  - changed one of the dubugs to so post processing of the input
	        data. 

030407	Bugs uncovered by Charlie Reitsma <reitsmac@denison.edu>:
	HOWTO incorrectly specified penctl in place of penlog
	in Apache configuration example, and using penctl to
	redirect log to penlogd didn't work.
	Avoid bogus header rewriting in rewrite_request.
	Released 0.10.1.

030210	New penctl commands "http" and "no http" to toggle -H.

030208	New option -H adds X-Forwarded-For header to http requests.

020717	Patches from Patroklos G. Argyroudis <argp@ieee.org>:
	 - check getopt() calls against -1 and not EOF
	 - fix for a possible format string in pen.c

020711	Ported to Darwin/MacOS X.
	Released 0.9.4.

020705	New penctl command: recent [seconds] displays clients that have
	connected recently (default five minutes), along with number of
	connects, transmitted and received data.

020702	Buffer overflow in netlog. See comment in pen.c.
	Added options -j (for chroot) and -u (for setuid) to pen and
	penlogd. See manpages.

020627	Fixed an error which could throw penlogd into an endless loop
	if a udp packet was lost at the crucial moment.

020626	Pedantic checking of memory allocations and buffer sizes.

020618	Penlogd: added option -n to adjust the number of cached log
	entries from Pen.

020614	Added options -d, -f, -l and -p to penlogd. They do the same
	as in pen. Also added signal handlers for TERM and HUP; these
	too do the same as in pen. Updated penlogd manpage.
	Updated www section in HOWTO to use penlog rather than mergelogs.

020613	Added penlog.c to log over a network using Apaches reliable
	piped logs. A companion log server, penlogd.c, consolidates
	logs from Pen and from all web servers into a single file.
	Added the necessary code to Pen log over the network.

020610	Wrote penctl.cgi, a web wrapper for penctl.

020609	Wrote a new version of the main loop, using poll() instead of
	select(). Added configuration option --with-poll to enable.
	Also turned redefinition of FD_SETSIZE into a configuration
	option --with-fd_setsize=N.
	Updated installation instructions in INSTALL.

020605	Added optional hard limit to the number of connections to each
	server.
	Timestamps in debug log entries.
	Released 0.8.0.

020604	Added "server of last resort" (-e option) which is only used
	when all other servers are unavailable. (Andreas Wrede)

020528	Several enhancements and bugfixes by Andreas Wrede:
	In webstats: changed CLIENTS_MAX to clients_max and
	CONNECTIONS_MAX to connections_max.
	Show time in human-readable format rather than seconds since 1970.
	Changed byte counters from unsigned long to unsigned long long.
	Fixed file descriptor leak: The connection wasn't closed when
	the connection table was full.
	Moved stats generation and log restart out of the signal handlers
	and into the main loop.
	If a client went away before receiving all its data (large files),
	the remaining portion would be sent to the next client occupying
	the same slot.
	Added pointers in connection structure to avoid having to memcpy
	the buffers in flush_up/flush_down.
	Released 0.7.0.

020507	Updated the penctl manpage to reflect reality.
	Released 0.6.3.

020417	Added -D switch to make copy_up and copy_down *always* store data
	in a temporary buffer and wait for the next round through the
	main loop before passing it on to the receiving end.
	The penctl command for this is "delayed_forward".
	When making sockets nonblocking (through fcntl(..., O_NONBLOCK)),
	make sure that any existing flags are not reset in the process.
	Important bugfix: each failed connection attempt in try_server
	would result in one socket leaked because we returned without
	closing it.

020413	Figured out why nonblocking mode was slower than blocking. Fixed.

020411	Added penctl, a simple user interface to the control protocol.

020324	Cancel timeout if it isn't needed.

020115	Added LDAP info in the HOWTO.
	Added the flush_up/flush_down bugfix from 0.5.0 again.
	Released 0.6.1.

020111	Moved #include <sys/types.h> before #include <netinet/in.h>
	Replaced the call to setpgrp with setsid.
	Transformed mergelogs into ultimately portable ANSI C (almost).
	Thanks to Mike Dugas <mad@phobia.net> for help with porting
	to FreeBSD 4.4-RELEASE.

020110	Rewrote mergelogs completely. It will now never discard a web
	server log entry, and it tries much harder to locate a good
	match in the pen log. It deals with log entries that are out
	of order and servers with unsynchronized clocks and/or
	different time zones. The -l (lag) option is no more.
	Removed the -r (rejects) option, since we no longer reject anything.
	Released 0.6.0

010915	Made the use of daemon() optional.
	Added the cgi script penstats to update and display statistics.
	Set current in store_conn.
	Released 0.5.0.

010914	Statistics in HTML format (Riccard kerman).
	Tested pen on HP-UX 10.20.

010913	Released 0.4.0.

010912	When storing part of the buffer for a renewed attempt,
	store the *end*, not the beginning. Affects copy_up and copy_down.
	Autoconf. Use daemon() if available. Make sure that we don't try
	to close uninitialized file handles in add_client.
	New option -n to not make sockets nonblocking (mainly useful
	for debugging).

010911	Make sure that remaining data is stored away when we get EAGAIN
	in copy_up.
	Released 0.3.3.

010909	Added -p argument to store process id in a file (Andreas Wrede).
	Made the sockets nonblocking. Handle EAGAIN in copy_up/down.
	Released 0.3.2.

010908	Ignore SIGPIPE. Released 0.3.1.

010827	Option -h uses a hash on the client IP address for the initial
	server selection. Option -s ("stubborn") prevents failover to
	another server if the initial choice is unavailable.

010824	Use getport for the local port as well.

010820	Append to the logfile rather than overwriting it.
	Released 0.2.0.

010817	Server selection algorithm rewritten in a cleaner, simpler way.
	Blacklist nonresponding servers for a selectable period of time.
	Optional "plain" roundrobin without client tracking.
	(options -b and -r, see manpage).
	Log to syslog if we are running in the background.

010814	Installed pen on siag.nu, which now load-balances itself. Apache
	runs on port 8080, pen on 80. Seems to work (tm).

010813	Added description of options to pen.1 and mergelogs.1.
	Script to guess libraries.

010812	Fixed typo (webmerge -> mergelogs) in pen.1.

010809	Added mergelogs, a program to match pen logs against web server
	logs and merge the results into one log file with the correct
	client addresses.
	Released 0.1.0.

010808	Print statistics on stderr when sent USR1 signal.
	Ported to Solaris, i.e. verified that it works ;-).
	Logging. Reopen log file when sent HUP signal.
	Exit cleanly when sent TERM signal.

010807	Wrote a manpage.

010803	Completed the conversion to non-forking, selecting mode. Works
	really well now, with very low CPU utilization even with many
	simultaneous connections.

010729	Rewrote the program to not fork.

010722	Prettied up the source.

001218	Updated the README.

001022	Rewrote the load balancing algorithm.