#!/bin/bash
#
# Helper program for subscribing NetBIOS names to resolvconf
# Copyright (C) 2016 Daniel Boland <d.boland@rocleiden.nl>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

NMBLOOKUP=`which nmblookup`
TESTPARM=`which testparm`
DIG=`which dig`

if ! [ $NMBLOOKUP ]; then
	echo "This script needs the 'nmblookup' program."
	exit 1
elif ! [ $TESTPARM ]; then
	echo "This script needs the 'testparm' program."
	exit 1
elif ! [ $DIG ]; then
	echo "This script needs the 'dig' program."
	exit 1
fi

GROUP=`$TESTPARM -s --parameter-name=workgroup 2>/dev/null`
MASTER=""
ADDRESS=""
NBTHOST=""

function print_resolv {
	DOMAIN=`$DIG @$MASTER +noall +answer -x $MASTER | awk '{print $NF}' | sed 's/[^.]\+.//; s/.$//'`
	echo "search $DOMAIN"
	echo "nameserver $MASTER"
}
function lookup_master {
	MASTER=`$NMBLOOKUP $GROUP#1b | grep "$GROUP<1b>" | awk '{print $1}'`
	if ! [ $MASTER ]; then
		echo
		echo "Domain master for workgroup '$GROUP' not found." >&2
		exit 1
	fi
}
function lookup_nbthost {
	while read -r; do
		fields=($REPLY)
		case "${fields[1]}" in
			"<20>")
				echo " NetBIOS hostname is '${fields[0]}'"
				NBTHOST=${fields[0]}
				;;
			"<1b>")
				echo " Host is a master browser for workgroup '${fields[0]}'"
				;;
			"<1c>")
				echo " Host is a domain controller for workgroup '${fields[0]}'"
				;;
			"<1d>")
				echo " Host is a computer browser for workgroup '${fields[0]}'"
				;;
		esac
	done <<<"`$NMBLOOKUP -A "$1" | grep "<ACTIVE>" | awk '{print $1 " " $2}'`"
}
function lookup_host {
	info=(`host $1 | awk '{print $1 " " $NF}'`)
	if [[ ${info[1]} =~ "NXDOMAIN" ]]; then
		echo " Could not lookup host '$1'"
	else
		echo " ${info[0]} has address ${info[1]}"
		echo -n " "
		host ${info[1]}
	fi
}

function set_group {
	if ! [[ `$NMBLOOKUP $1 | grep "$1<00>" | awk '{print $1}'` ]]; then
		echo "$1: No such workgroup." >&2
		exit 1
	fi
	GROUP=`echo "$1" | awk '{print toupper($0)}'`
}

while [ $1 ]; do
	case $1 in
		-h|--help)
			COMMAND="help"
			;;
		-A|--lookup-by-ip)
			ADDRESS="$2"
			COMMAND="lookup"
			shift
			;;
		-*)
			echo "$1: No such option."
			exit 1
			;;
		status)
			COMMAND="$1"
			;;
		*)
			set_group "$1"
			;;
	esac
	shift
done

function do_help {
        printf 'Usage: %s [COMMAND] [options] [WORKGROUP]\n' `basename $0`
	echo
	echo "Commands:"
	printf -- " status\t\t\t\tPerform some status tests on server and client\n"
        echo
        echo "Options:"
	printf -- " -A,--lookup-by-ip [HOST]\tDo a node status on HOST as an IP Address\n"
	printf -- " -h,--help\t\t\tThis help text\n"
}
function do_add {
	lookup_master
	print_resolv | /sbin/resolvconf -a lo.$PROGRAM
}
function do_lookup {
	lookup_nbthost $ADDRESS
}
function do_status {
	lookup_master
	echo "Winbind:"
	echo -n " " && wbinfo -p 2>/dev/null
	echo -n " " && wbinfo -t 2>/dev/null
	echo "Server:"
	lookup_nbthost $MASTER
	lookup_host $NBTHOST
	echo "Client:"
	lookup_host `hostname -s`
	echo -n " " && net rpc testjoin 2>&1 | tail -1
}

if [ $COMMAND ]; then
	do_$COMMAND
else
	lookup_master
	print_resolv
fi