MOHAA Linux admin tool - UPDATE

Sat Sep 7 11:40:55 EDT 2002

Hello everyone!

I have been working on the programs and am happy to report that the server component is finished and it appears to be stable after the last batch of tests I have run.  The client program is also functional, but I am going to work on it a little more before I release anything just to be sure I worked out most of the kinks.  In the meantime, I figured it might be a good idea to let everyone know some more of the technical details.  This way if anyone has any ideas, comments, questions, or criticisms I can address them before I release the code.  Hopefully this will make it a better utility in the long run.  Having said that, here is a list of the loader's features:

- Configuration file
    On startup, a configuration file is read to provide the loader with information needed to operate the game server and the loader itself.  This is where the command to launch MOHAA is located along with several other settings that adjust how the loader operates.  If you are running more than one server on a system, they should each have their own config file specified on the command line.  Below is a copy of the configuration file I am currently using:

#
#  MOHAA Loader Configuration File
#
#  - All characters after a "#" on a line are comments and will be ignored.
#  - All blank lines will be ignored.
#  - The only option that must be specified in this file is PROGRAM.  Without
#    it, the loader cannot operate.  All other settings have defaults already
#    specified within the loader itself.
#

#
# Specify the fully qualified path to the game server program including all
# command line options.
#
PROGRAM = /usr/local/games/MOHAA/mohaa_lnxded +set dedicated 1 +set cheats 0 +set ui_console 1 +set g_gametype 2 +set sv_maxclients 18 +set developer 2 +map dm/mohdm1 +exec server.cfg

#
# Specify message broadcast interval in seconds.
#
MSG_INTERVAL = 300

#
# Specify if messages are to be printed.  Setting this to anything other than
# "Y" will suppress message output to the server.  Normal processing will
# continue regardless of how this is set.
#
MSG_PRINT = Y

#
# Specify limit of how many lines of the total message to print during each
# broadcast.  Setting this to any value less than "1" will not impose any limit
# at all.  Values of "1" or greater will cause the number of lines specified by
# this value to print with the appropriate MSG_LINE_DELAY between each line.
# Once the limit has been reached, the program will pause for the number of
# seconds indicated by MSG_INTERVAL.
#
MSG_LINE_LIMIT = 0

#
# Specify the amount of time to wait between printing each line in seconds.
#
MSG_LINE_DELAY = 0

#
# Specify server broadcast message content.  Each line of text must begin with
# the text "MSG_LINE" and will be broadcast in the order it appears here.  If
# you want to split broadcasts into logical groups using the MSG_LINE_LIMIT
# setting but don't want to print content for all possible lines in a given
# grouping, use a null line:
#       e.g.  MSG_LINE = NULL
# The line will count towards the limit, but not be printed.
#
MSG_LINE = Welcome to RAGNAROK!  Server IP: 216.42.80.176
MSG_LINE = Server Admin email: shockwave at clanshortfuse.com
MSG_LINE = No Realism.  Friendly Fire OFF.  Have fun and fight honorably.

#
# Ban messages can be tailored by using the BAN_MSG_START and BAN_MSG_END
# config variables.  The START component will be printed before the player's
# name and the END component will be printed after the player's name.  After
# the player has been kicked, the message will be assembled and sent to the
# console.
#

#
# Specify start text of ban message.
#
BAN_MSG_START =

#
# Specify end text of ban message.
#
BAN_MSG_END =

#####################
#
# E O F
#

    The configuration file is re-read after each message interval has elapsed to provide for the ability to change every setting with the exception of PROGRAM.  Simply use a text editor and make whatever changes you require and they will be picked up during the next message cycle, whether you have opted to broadcast anything or not.
    I spent some time thinking about how to handle server message broadcasts and I tried to develop a structure that would be both easy to use and flexible.  I have tested every combination I could think of and everything runs smoothly.  If the explanation given in the configuration file of how it all works still leaves anyone with questions, please let me know.  Also, if anyone requires message handling that this system doesn't support I'd like to hear the specifics.

- Command line overrides
    Options can be placed on the command line to override program defaults not handled by the configuration file.  Here is the output generated by invoking the loader's --help option:

Usage: mohaa_loader [--host host] [--port port] [--cfg filename] [--log filename] [--ban filename]
       mohaa_loader --defaults
       mohaa_loader --help

        --host   IP address or host name: name must resolve to an IP address
                   (e.g. localhost  or  192.168.1.1  or  www.myserver.com)
        --port   port number
        --cfg    path to configuration file, including filename itself
                   (e.g.  /usr/local/games/MOHAA/yourconfig.cfg)
        --log    path to game server log file, including filename itself
                   (e.g.  /usr/local/games/MOHAA/server.log)
        --ban    path to banned IP file, including filename itself
                   (e.g.  /usr/local/games/MOHAA/badboys.cfg)

        --defaults
            prints current program defaults and exits
        --help
            prints this usage information and exits

    As you can see, you have the ability to either share or specify different files for banned IP addresses.  However, it is important to note that the log files and configuration files for each server you are running be separate and properly specified on the command line.  Running the command with the --defaults option will dump the internal program defaults so you can see what the settings will be if they are not overridden either on the command line or in the configuration file.
    I also want to take a moment and discuss the --host and --port options, specifically as they relate to system security.  I have set the program default for --host to  "localhost" because I didn't employ any encryption on the socket connections.  Specifying an Internet address means that the socket will be exposed externally and that might not be the best idea.  Personally, I use PuTTY (a free utility found here:  http://www.chiark.greenend.org.uk/~sgtatham/putty/ ) to connect to the game server if I'm using a Windows system or "ssh" from the Linux shell prompt if I'm on a Linux system because the connection is encrypted.  Once connected, I invoke the program I want to run by using the "screen" program (e.g. screen batch_file_that_starts_loader).  This allows me to <Ctrl><A><Ctrl><D> to detach from the process and keep it running.  I can then disconnect and go about my business.  To regain control, I ssh back into the server and issue the command "screen -r" to pick up the process.  I can <Ctrl><C> at any time while connected to the process to kill it entirely.  I apologize if this is review for any of you, but I want to be sure I explain the situation thoroughly.

- Game server by clients via sockets
    The loader starts the game server using a piped open in order to feed input to the server process.  Once the server is running, the loader forks processes to handle server messaging, monitoring output for kicking banned IP's, and servicing incoming client connections.  If the client connection process receives a connection request, it forks two processes to handle input and output from the client respectively.  Each additional client that connects will receive its own set of I/O processes as well.  So far I have connected with two clients at the same time and everything worked well.  The client program operates similarly and forks to accommodate I/O on separate processes.  The result is smooth traffic flow without devouring large amounts of server resources. Unfortunately, I was unable to latch onto the output from the game server itself directly.  Piped opens, IPC::Open2, and named pipes didn't seem to allow it much less facilitate good communications with clients attempting to connect to the loader.  Therefore, server output is processed by opening filehandles to the server log and tailing it.  The data is fed to the loader's input channel and subsequently out via sockets to each client connected.

- Banned IP file handling
    As I stated earlier, there is a process running whose job is solely to monitor server output and react accordingly.  This is the process that watches for banned players.  When a player connects, it re-reads the banned IP file and checks it against the players currently connected to the server.  Upon getting a match, the player in question is kicked and a ban message is output to the server.

======

Well, that's about all I have for now.  I've been a little short on sleep lately, so I apologize in advance for anything I may have omitted.  Next on the list will be finishing off the client program so I can release everything to those who have expressed an interest in testing.  Any feedback, technical or otherwise, is solicited.  I want to make this a viable tool for all of us who are responsible for administrating Linux MOHAA game servers and the best way to do that is to maintain an open forum.  Thanks for your time and I'll let everyone know when the client is finished.  With any luck it will be either today or tomorrow.

Shockwave
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