#!/bin/bash
######################################################################
#
#  hexroute - Convert human readable routes to dhcpd static route info
#             for Windows(r) clients
#
#  Copyright (c) 2005-2015 Karl McMurdo
#
#  Freely distributable, but please keep header intact
#
#  Update: May 10, 2007 Change Max Quad to 255
#
######################################################################

function split_ipaddr() {
[ ${1:-X} = X -o "${1}" != ${1//[^.0-9]/} -o ${1:-X} = X \
    -o "${1//[0-9]/}" != "..." ] && return 1
	local rval=0
	local t
	local T[1]
	local T[2]
	local T[3]
	local T[4]
	T[1]=${1%%.*}
	T[2]=${1#*.}
	T[2]=${T[2]%%.*}
	T[3]=${1#*.*.}
	T[3]=${T[3]%%.*}
	T[4]=${1#*.*.*.}
	[ ${T[1]} = 0 ] && rval=1
	for t in 1 2 3 4
	do
		[ ${T[${t}]:-999} -gt 255 ] && rval=1
		eval "${2}[${t}]=${T[${t}]}"
	done
	return ${rval}
}
USAGE='echo -e "Usage: ${0//*\/} [-v|-h] target/bits [gw] gateway [target/bits [gw] gateway ...]\n\n\tie: ${0} 172.16.0.0/16 gw 192.168.1.1\n" && exit 1'
INFO="HexRoute 1.0    Copyright (c) 2015 Karl McMurdo

Converts human readable route information to a dhcpd hex string

	-v	Once prints full dhcpd.conf line for route(s)
		Twice also prints option definiton lines for dhcpd.conf
	-h	Prints this message
"
DHCPHDR="# New Option Type for Windows Client Static Routes
option new-static-routes code 249 = string;"
DHCPS="option new-static-routes "
DHCPE=";"
BADTARG='echo -e "Invalid target network: ${1}" && exit 2'
BADBITS='echo -e "Invalid Network bit value: ${1}" && exit 3'
BADGW='echo -e "Invalid Gateway: ${2}" && exit 4'
VERBOSE=false
EXTRAVERBOSE=false

while [ "${1:0:1}" = "-" ]
do
	if [ "${1}" = "-v" ]
	then
		$VERBOSE && EXTRAVERBOSE=true
		VERBOSE=true
	elif [ "${1}" = "-h" ]
	then
		echo "${INFO}"
		eval "${USAGE}"
	else
		eval "${USAGE}"
	fi
	shift
done

[ ${#} -lt 2 ] && eval "${USAGE}"
OUT=""

while [ ${#} -ge 2 ]
do
	split_ipaddr ${1/\/*/} TARG || eval "${BADTARG}"
	BITS=${1/*\//}
	shift
	[ ${BITS:-X} = X -o "${BITS}" != ${BITS//[^0-9]/} ] && eval "${BADBITS}"
	[ ${BITS} -gt 32 -o ${BITS} -lt 1 ] && eval "${BADBITS}"
	[ ${1:-X} = gw ] && shift
	split_ipaddr ${1:-X} GW || eval "${BADGW}"
	shift
	OUT=${OUT}$( printf ":%02x:%02x" ${BITS} ${TARG[1]} )
	[ ${BITS} -gt 8 ]  && OUT=${OUT}$( printf ":%02x" ${TARG[2]} )
	[ ${BITS} -gt 16 ] && OUT=${OUT}$( printf ":%02x" ${TARG[3]} )
	[ ${BITS} -gt 24 ] && OUT=${OUT}$( printf ":%02x" ${TARG[4]} )
	OUT=${OUT}$( printf ":%02x:%02x:%02x:%02x" ${GW[@]} )
done

$EXTRAVERBOSE && echo "${DHCPHDR}"
if $VERBOSE
then
	echo ${DHCPS}${OUT/:/}${DHCPE}
else
	echo ${OUT/:/}
fi