Munin contributed plugins

#!/bin/bash

#

# Plugin to monitor the number of hosts in /etc/hosts.deny

# that are denied access to sshd

# Copyright (C) 2010 Lothar Schmidt, l.munin@scarydevilmonastery.net

#                                    Bushmills on #munin, irc.freenode.net

#                                    latest versions on http://scarydevilmonastery.net/munin.cgi

#

# This 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 3 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

#

# ------------------------------------------------------------------------------------------------------

# 20100310  v1.01  ls

#               as threatened, shows now "temperatures" of active hosts.deny lines. Recent additions are

#               displayed in bright red, turning to blue as older the addition rules are.

#               This requires denyhosts to add line to hosts.deny in a specific format. Also, times are currently

#               hardcoded, and not a lot of flexibility adjusting them through parameters.

#               A line in hosts.deny should come with a comment, looking like:

#               # DenyHosts: Sat Mar  6 01:11:57 2010 | sshd: 87.101.51.198

#               8 graphs are drawn from that depicting number of rules in 24 h increments. Different colours are

#               assigned to graphs which are <24h, 24-48h, 48-72h ... old. The last (coldest) graph shows rules

#               which have been added > 168h ago.

#               I'm considerering to change age granularity to hours, rather than days, and plot many graphs (64 or 128,

#               which are nice for colour calculations), showing more of a colour cloud than discernible areas.

#               The plugin must have permission to read /etc/hosts.deny, of course.

# 20100308, v1.0, ls

#               Will probably add multiple stacked graphs, indicative for addition/removal date of denies,

#               instead of a boring single area graph.

# ------------------------------------------------------------------------------------------------------

#%# family=manual

#%# capabilities=autoconf

# ------------------------------------------------------------------------------------------------------

DENY="/etc/hosts.deny"

NAME="$(basename "$0")"                                        # component of naming temporary files

STATEFILE="$MUNIN_PLUGSTATE/$NAME.state"

COLOUR=(FF0000 DA0024 B60048 91006D 6D0091 4800B6 2400DA 0000FF)  # hot to cold colours

# ------------------------------------------------------------------------------------------------------

run_autoconf()  {

        RUN="no (denyhosts not found)"

        command -v denyhosts > /dev/null && RUN="yes"             # only run when denyhosts is present

        echo "$RUN"

}

run_config()  {

	cat << EOF

graph_title Hosts denied sshd access

graph_info Hosts denied sshd access in $DENY

graph_args --base 1000 -l 0

graph_vlabel Hosts denied

graph_category security

EOF

for AGE in {7..0}; do

	if [ "${AGE}" = 0 ]; then

		echo "age${AGE}.label added last 24h"

	else

		echo "age${AGE}.label older than $((AGE*24))h"

	fi

	cat << EOF

age${AGE}.draw AREASTACK

age${AGE}.colour ${COLOUR[$AGE]}

EOF

done

}

run_fetch()   {

   TOTAL=0

   NOW=$(date +%s)

   sed -n 's/^\# DenyHosts: //;s/ | .*//gp' $DENY |         # strip all but date

   while read -r DATE; do

      echo $(((NOW - $(date -d "$DATE" +%s))/86400))        # calculate rule age

   done > "$STATEFILE"                                      # rather than going through temp file, the age could be

   for AGE in {6..0} ; do                                   # used to increment an array element with that index.

      COUNT="$(grep -c "^$AGE$" "$STATEFILE")"              # That'd save grepping for counting from temp file.

      echo "age${AGE}.value $COUNT"                         # produce values for all but oldest

      ((TOTAL+=COUNT))

   done

   echo "age7.value $(($(grep -c . "$STATEFILE")-TOTAL))"   # all non-printed are older

   rm "$STATEFILE"

}

run_"${1:-fetch}"

exit 0