#!/bin/bash
#
# Copyright 2014,2015,2016,2017,2018,2019,2020,2021 Security Onion Solutions, LLC
#
# 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/>.


APP=suriloss
lf=/tmp/$APP-pidLockFile
# create empty lock file if none exists
cat /dev/null >> $lf
read lastPID < $lf
# if lastPID is not null and a process with that pid exists , exit
[ ! -z "$lastPID" -a -d /proc/$lastPID ] && exit
echo $$ > $lf

SURILOG=$(tac /var/log/suricata/stats.log | grep kernel | head -4)
CHECKIT=$(echo $SURILOG | grep -o 'drop' | wc -l)

if [ $CHECKIT == 2 ]; then
  declare RESULT=($SURILOG)

  CURRENTDROP=${RESULT[4]}
  PASTDROP=${RESULT[14]}
  DROPPED=$((CURRENTDROP - PASTDROP))
  if [ $DROPPED == 0 ]; then
    LOSS=0
    echo "suridrop drop=0"
  else
    CURRENTPACKETS=${RESULT[9]}
    PASTPACKETS=${RESULT[19]}
    TOTALCURRENT=$((CURRENTPACKETS + CURRENTDROP))
    TOTALPAST=$((PASTPACKETS + PASTDROP))
    TOTAL=$((TOTALCURRENT - TOTALPAST))

    LOSS=$(echo 4 k $DROPPED $TOTAL / p | dc)
    echo "suridrop drop=$LOSS"
  fi
else
  echo "suridrop drop=0"
fi