build_dhcpd

#!/bin/bash
#
# build_dhcpd
#
# Written by: Matt Pascoe <matt@opennetadmin.com>
#
# License:
#  build_dhcpd (hereafter referred to as "program") is free software;
#  you can redistribute it and/or modify it under the terms of the GNU General
#  Public License as published by the Free Software Foundation; either version
#  2 of the License, or (at your option) any later version.
#  Note that when redistributing modified versions of this source code, you
#  must ensure that this disclaimer and the above coder's names are included
#  VERBATIM in the modified code.
# 
# Disclaimer:
#  This program is provided with no warranty of any kind, either expressed or
#  implied.  It is the responsibility of the user (you) to fully research and
#  comprehend the usage of this program.  As with any tool, it can be misused,
#  either intentionally (you're a vandal) or unintentionally (you're a moron).
#  THE AUTHOR(S) IS(ARE) NOT RESPONSIBLE FOR ANYTHING YOU DO WITH THIS PROGRAM
#  or anything that happens because of your use (or misuse) of this program,
#  including but not limited to anything you, your lawyers, or anyone else
#  can dream up.  And now, a relevant quote directly from the GPL:
# 
# NO WARRANTY
# 
#  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
#  FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
#  OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
#  PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
#  OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
#  TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
#  PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
#  REPAIR OR CORRECTION.
# 
# The GNU GPL can be found at http://www.fsf.org/copyleft/gpl.html
# 
# -----------------------------------------------------------------------
# Description
#
#
# THIS IS A REFERENCE DESIGN BUILD SCRIPT, IT WORKS FOR ME BUT MAY NOT FOR YOU
# IT IS INTENDED TO GIVE AN EXAMPLE OF HOW A SCRIPT LIKE THIS COULD BE BUILT.  IF IT WORKS
# FOR YOU, GREAT!  IF NOT THEN MAKE WHATEVER ADJUSTMENTS TO IT YOU NEED TO GET IT WORKING!
# ASK FOR HELP IN THE FORUMS IF NEEDED.
#
# REQUIRES: dcm.pl, build_dhcpd_conf module, working ISC dhcpd for the local server, sendEmail
#
# Since this script must restart the dhcpd daemon, it should be ran as the dhcp user or as root.
#
# dcm.pl should be working on your system and either in your path or you will need to put the full path to it in the DCM_PATH variable below.
#
# Remember that the checks done by dhcpd -t are only syntax checks.  They will not ensure that the content of your files is correct.
# If you have missing records or incorrect data it could impact your environment.
#
# The local host name as determined using "hostname -f" must match the FQDN of the server in ONA.  It must be the PRIMARY name, not an CNAME
# or alternate A record. You can also specify another name using the -s option and providing an FQDN from ONA.
#
# For ease of use, it is recommended to add /opt/ona/bin to your $PATH environment variable
#
# You should create a symlink for your system dhcpd.conf file, Probably in /etc/dhcpd3/dhcpd.conf depending on your system,
# that points to the configuration file built by this script.  The config file built will be located in $ONA_PATH.
#
# A header file is required that will contain directives like "authoritative", ddns-update-style, or logging statements etc
# in the main config file as these are out of scope for the ONA system to manage at this point.  You can also
# define other options your site may require that are not possible to manage in ONA.
# The header file will be built as an 'include' statement at the top of the generated config file.
# Add the following line to your system dhcpd.conf file. Probably in /etc/dhcpd3/dhcpd.conf depending on your system.

# You may need to configure directives like "authoritative", ddns-update-style, or logging statements etc in the main config file as these are
# out of scope for the ONA system to manage at this point.
# The placement of this line could vary depending on how your distro organizes dhcpd.  /etc/dhcpd3/dhcpd.conf should be used for ubuntu/debian based systems.
#
#     include "/opt/ona/etc/dhcpd/dhcpd.conf.ona";
#
# You will need to execute the following dcm command to automatically create the appropriate module entries:
#
# NOTE: Some distros use the Linux Terminal Server Project (LTSP) version of dhcp config file instead, be aware of that.
# NOTE: to view example configs in the GUI you need to set build_dhcp_type to "isc" or "dhcpd" in the sys_config table, this is done by the installer.
#
# Batch mode [-b] is used to remotely execute this script and return a SUCCESS or FAILURE message only.  This can be
# used by an ssh key execution for example.
#
# -----------------------------------------------------------------------
# onabase should contain the path to your ONA install, usually /opt/ona
[ ! -r /etc/onabase ] && echo "[$0] ERROR: Unable to read /etc/onabase." && exit 1
ONABASE=`cat /etc/onabase`

# this will default to placing data files in /opt/ona/etc/dhcpd, you can update the following for your system as needed
# for things like chroot jails etc
ONA_PATH="${ONABASE}/etc/dhcpd"

# Get the local hosts FQDN.  It will be an assumption!! that it is the same as the hostname in ONA
# Also, the use of hostname -f can vary from system type to system type.  be aware!
SRV_FQDN=`hostname -f`

# Path to the dcm.pl command.  Also include any options that might be needed
DCM_PATH="${ONABASE}/bin/dcm.pl"

# For now a path is required to a default header.
# this will have things like the authoritative statement,ddns-update-style, and other required options
# this header should contain things that are static and rarely change
# it can also contain localized configuration not maintained by ONA
# This value must not be blank
HEADER_PATH="${ONA_PATH}/dhcpd.conf.ona.header"

# Remove the temporary configuration files that are older than $DAYSOLD.  This uses the find
# command to remove anything older than this amount of days.  These are configs that had an
# error for some reason.
DAYSOLD=30

# The path to the system init script that is responsible for restarting the dhcpd service
# also include the restart option to the init script that is appropriate for your system
SYSTEMINIT="/etc/init.d/dhcpd restart"

# The systems DHCPD binary file.  Enter full path if needed
DHCPDBIN=/usr/sbin/dhcpd

# Email settings for config_archive to send status information to (diffs etc)
MAIL_SERVER=mail.example.com               # name or IP of the mail server to use
MAIL_FROM=ona-build_dhcpd@$SRV_FQDN        # email address to use in the from field
MAIL_TO=oncall@example.com                 # email address(es) to send our notifications to


###################### No need to change anything below here ################################

# This will log a message in a standardized way
# Its job is simple.. take the message that was passed in and log it via some mechanism.
# Currently, it echos to stdout and logs in syslog
function ONA_LOG {
    # Log it to the screen
    [ $BATCHMODE ] || echo $(date +'%h %d %H:%M:%S') [ONA:$(basename $0)]: "$1"

    # log it to syslog
    logger -t [ONA:$(basename $0)] "$1"
}

# This function will exit with a status of 1 and if in batch mode, will print a success/fail message
function ABEND {
    [ $BATCHMODE ] && echo FAILURE
    # send an email notification
    sendEmail -s $MAIL_SERVER -f $MAIL_FROM -t $MAIL_TO \
              -u "[ONA:$(basename $0)] $SRV_FQDN: Failure during DHCP rebuild." \
              -m "The DHCP server '$SRV_FQDN' has encountered a failure during its last rebuild, please check the status of the server.  You can try the following command on this server to display why this configuration test failed: $DHCPDBIN -t -cf $ONA_PATH/dhcpd.conf.ona.$TMSTAMP"
    if [ $? -ne 0 ]
    then
        ONA_LOG "ERROR => There was an issue sending the notification email."
    fi
    exit 1
}

#### Process the commandline options
USAGE="
Usage: `basename $0` [-s <FQDN>] [-b] [-d] [-t]

  -s     FQDN of the server you wish to build DHCP configs for
  -b     Enable batch mode (less logging for scripted runs)
  -d     Enable debug output
  -t     Test only, don't restart server process
"

while getopts "s:bdt" options; do
  case $options in
    b ) BATCHMODE=1;;
    d ) DEBUGON=1;;
    t ) TESTONLY=1;;
    s ) SRV_FQDN=$OPTARG;;
    \? ) echo "$USAGE"
         exit 1;;
    * ) echo "$USAGE"
         exit 1;;
  esac
done


# Check that $ONA_PATH directory exists
if ! test -d $ONA_PATH 
then
    ONA_LOG "ERROR => Unable to find directory '$ONA_PATH', please create it."
    ABEND
fi

[ $BATCHMODE ] || ONA_LOG "INFO => Building ISC DHCPD config for $SRV_FQDN..."

# Get a timestamp to name our temp file with
TMSTAMP=`date +%Y%m%d%H%M%S`

# Build the conf file
# Start with including the local header file
echo > $ONA_PATH/dhcpd.conf.ona.$TMSTAMP
echo "include \"$HEADER_PATH\";" >> $ONA_PATH/dhcpd.conf.ona.$TMSTAMP
echo >> $ONA_PATH/dhcpd.conf.ona.$TMSTAMP
echo >> $ONA_PATH/dhcpd.conf.ona.$TMSTAMP

# Get config from database and append it to our temp file
if ! $DCM_PATH -r build_dhcpd_conf server=$SRV_FQDN >> $ONA_PATH/dhcpd.conf.ona.$TMSTAMP
then
    ONA_LOG "ERROR => Unable to build ISC dhcpd config file."
    ABEND
fi

[ $DEBUGON ] && ONA_LOG "DEBUG => Testing new config files for SYNTAX only..."

if ! test -x $DHCPDBIN
then
    ONA_LOG "ERROR => Unable to find DHCP binary '$DHCPDBIN'."
    ABEND
fi

# Test that our new config is syntacticaly correct
# If you are using a different dhcp.conf file that includes what is built from ONA you could
# possibly run into issues where the syntax check passes but the restart fails.  This typically
# happens when there is duplicate information in the two files
if ! $DHCPDBIN -t -cf $ONA_PATH/dhcpd.conf.ona.$TMSTAMP > /dev/null 2>&1
then
    [ $DEBUGON ] && $DHCPDBIN -t -cf $ONA_PATH/dhcpd.conf.ona.$TMSTAMP 2>&1
    ONA_LOG "ERROR => The resulting config files have a syntax error."
    ABEND
else
    # Move the sucessfuly tested config file into the running config file
    mv $ONA_PATH/dhcpd.conf.ona.$TMSTAMP $ONA_PATH/dhcpd.conf.ona

    # Clean up old,failed, configs (only good for the next 100 years or so!)
    find $ONA_PATH/dhcpd.conf.ona.20* -type f -mtime +$DAYSOLD -exec rm -f '{}' > /dev/null 2>&1 \;
fi

# If we have the testonly option set, exit here so we dont reload the daemon
[ $TESTONLY ] && ONA_LOG "INFO => Test only, not restarting daemon."
[ $TESTONLY ] && exit 0

# Refresh the ISC dhcpd server
if ! $SYSTEMINIT > /dev/null 2>&1
then
    ONA_LOG "ERROR => Unable to reload the dhcpd daemon using the command '$SYSTEMINIT'." 
    ABEND
else
    [ $DEBUGON ] && ONA_LOG "DEBUG => Completed ISC DHCPD configuration extraction and daemon reload."
    [ $BATCHMODE ] && echo "SUCCESS"
    exit 0
fi