#!/bin/sh
#
#   Bindle Binaries Linux Firewall
#   Copyright (c) 2019 David M. Syzdek <david@syzdek.net>.
#
#   Redistribution and use in source and binary forms, with or without
#   modification, are permitted provided that the following conditions are
#   met:
#
#      * Redistributions of source code must retain the above copyright
#        notice, this list of conditions and the following disclaimer.
#      * Redistributions in binary form must reproduce the above copyright
#        notice, this list of conditions and the following disclaimer in the
#        documentation and/or other materials provided with the distribution.
#      * Neither the name of David M. Syzdek nor the
#        names of its contributors may be used to endorse or promote products
#        derived from this software without specific prior written permission.
#
#   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
#   IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
#   THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
#   PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DAVID M. SYZDEK BE LIABLE FOR
#   ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
#   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
#   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
#   CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
#   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
#   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
#   SUCH DAMAGE.
#


###############
# ENVIRONMENT #
###############

PATH=/usr/bin:/bin:/usr/sbin:/sbin
export PATH


# sets script/package information
PROG_NAME="$(basename "${0}")"
PACKAGE_NAME="$(echo '@PACKAGE_NAME@' |sed -e 's/[@].*[@]/ /g')"
PACKAGE_VERSION="$(echo '@PACKAGE_VERSION@' |sed -e 's/[@].*[@]/ /g')"
PACKAGE_BUGREPORT="$(echo '@PACKAGE_BUGREPORT@' |sed -e 's/[@].*[@]/ /g')"



#############
# FUNCTIONS #
#############

usage()
{
   printf "Usage: ${PROG_NAME} [OPTIONS]\n"
   printf "OPTIONS:\n"
   printf "  -h, --help                print this help and exit\n"
   printf "  -k, --kerneltime          print kernel timestamp\n"
   printf "  -n, --notime              do not print timestamp\n"
   printf "  -t, --timestamp           print human readable timestamp\n"
   printf "  -v, --version             print version and exit\n"
   printf "  -w, --follow              wait for new messages\n"
   printf "\n"
   printf "Please send bug reports to ${PACKAGE_BUGREPORT}.\n"
}


version()
{
   printf "${PROG_NAME} (${PACKAGE_NAME}) ${PACKAGE_VERSION}\n"
   printf "\n"
   printf "Please send bug reports to ${PACKAGE_BUGREPORT}.\n"
}


############
### MAIN ###
############

DMESG_TIME="-T"
DMESG_FOLLOW=""
DMESG_PATTERN=" IN=[-.:/a-zA-Z0-9]{0,} OUT=[-.:/a-zA-Z0-9]{0,} MAC=[:a-fA-F0-9]{0,} SRC=[:.0-9a-fA-F]{0,} DST=[:.0-9a-fA-F]{0,} "

while true; do
   case "$@" in
      -h|--help)       usage; exit 0;;
      -k|--kerneltime) DMESG_TIME=""; shift ;;
      -n|--notime)     DMESG_TIME="-t"; shift ;;
      -t|--timestamp)  DMESG_TIME="-T"; shift ;;
      -v|--version)    version; exit 0;;
      -w|--follow)     DMESG_FOLLOW="-w"; shift ;;
      "") break ;;
      --) shift; break ;;
      *) usage; exit 1 ;;
   esac
done


/bin/dmesg ${DMESG_TIME} ${DMESG_FOLLOW} \
   |egrep "${DMESG_PATTERN}" \
   |sed \
      -e 's/[^[:graph:]]/ /g' \
      -e 's/ip6tables drop: /,in,/g' \
      -e 's/ip6tables input: /,in,/g' \
      -e 's/ip6tables forward: /,fwd,/g' \
      -e 's/ip6tables output: /,out,/g' \
      -e 's/ip6tables blackhole: /,blkhol,/g' \
      -e 's/ip6tables \([-_a-z0-9:;,]\{1,\}\): /,\1,/gi' \
      -e 's/[[:space:][:cntrl:]]\{1,\}/ /g' \
      -e 's/ [[:upper:]]\{1,\} / /g' \
      -e 's/ MAC=[:[:xdigit:]]\{1,\} / /g' \
      -e 's/ ID=[[:digit:]]\{1,\} / /g' \
      -e 's/ TTL=[[:digit:]]\{1,\} / /g' \
      -e 's/ LEN=[[:digit:]]\{1,\} / /g' \
      -e 's/ URGP=[[:digit:]]\{1,\} / /g' \
      -e 's/ WINDOW=[[:digit:]]\{1,\} / /g' \
      -e 's/ PREC=0x[[:xdigit:]]\{1,\} / /g' \
      -e 's/ RES=0x[[:xdigit:]]\{1,\} / /g' \
      -e 's/ TOS=0x[[:xdigit:]]\{1,\} / /g' \
      -e 's/ ACK / /g' \
      -e 's/ CWR / /g' \
      -e 's/ DF / /g' \
      -e 's/ ECE / /g' \
      -e 's/ RST / /g' \
      -e 's/ SYN / /g' \
      -e 's/ PSH / /g' \
      -e 's/ \([A-Z]\{1,\}=\)/,\1/g' \
   |column -t -s ','


# End of scripts