#!/bin/bash
#
# Link Balancer - Policy Based Routing for humans...
#
#   Copyright
#
#       Copyright (C) 2015-2017 Costa Tsaousis <costa@tsaousis.gr>
#       Copyright (C) 2015-2017 Phil Whineray <phil@sanewall.org>
#
#   License
#
#       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 2 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/>.
#
#       See the file COPYING for details.
#
READLINK_CMD=${READLINK_CMD:-readlink}
BASENAME_CMD=${BASENAME_CMD:-basename}
DIRNAME_CMD=${DIRNAME_CMD:-dirname}
function realdir {
	local r="$1"; local t=$($READLINK_CMD "$r")
	while [ "$t" ]; do
		r=$(cd $($DIRNAME_CMD "$r") && cd $($DIRNAME_CMD "$t") && pwd -P)/$($BASENAME_CMD "$t")
		t=$($READLINK_CMD "$r")
	done
	$DIRNAME_CMD "$r"
}
PROGRAM_FILE="$0"
PROGRAM_DIR="${FIREHOL_OVERRIDE_PROGRAM_DIR:-$(realdir "$0")}"
PROGRAM_PWD="${PWD}"
declare -a PROGRAM_ORIGINAL_ARGS=("${@}")

for functions_file in install.config functions.common
do
	if [ -r "$PROGRAM_DIR/$functions_file" ]
	then
		source "$PROGRAM_DIR/$functions_file"
	else
		1>&2 echo "Cannot access $PROGRAM_DIR/$functions_file"
		exit 1
	fi
done

common_disable_localization || exit
common_private_umask || exit
common_require_root || exit

# make sure sbin is included in the path
# it seems that pppd ip-up.d script need this
export PATH="$PATH:/sbin:/usr/sbin:/usr/local/sbin"

if [ "$LB_DEBUGGING" ]; then set -v; set -x; fi

# link-balancer temporary directory.
# every instance of link-balancer creates a random directory
# within this one.
LB_RUN_DIR="$LOCALSTATEDIR/run/link-balancer"

# If this is set to 1, no checks will be made if the gateways are available.
# All gateways will be assumed active, if their interfaces are found
# operational.
# WHY: When we have a multi-ppp environment the default gateway of the system
# will be composed my multiple 'nexthop' routes. When a ppp device fails
# the kernel will remove the entire default gateway, not just the 'nexthop'
# that is not available any more.
# By calling link-balancer with option '-f' will enable this option.
# This option will make link-balancer restore the default gateway as soon
# as possible.
# 'link-balancer -f' should thus by called by ppp/ip-down scripts.
FORCE_ALWAYSON=0

# If set to 1, link-balancer will not change anything. It will just show
# what it will execute if run without it.
DRY_RUN=0

# If set to 1, link-balancer will output to standard-error all temporary files
# it generates during its execution.
DEBUG_ALL_DATA=0

# The step which increments the priority of the rules for each rule statement
# in the configuration file.
LB_RULE_STEP=100

# Keeps a list of all tables that have been altered during its run.
declare -A LB_ALTERED=()

# Where is the link-balancer configuration files?
LB_CONFIG_DIR="${FIREHOL_CONFIG_DIR}"

# Link-balancer main configuration file.
LB_CONFIG="${LB_CONFIG_DIR}/link-balancer.conf"

# takes either 4 or 6 to switch the functions in ipv4 or ipv6
LB_DEFAULT_IPV=4

marksreset() { :; }
markdef() { :; }
if [ -r "${FIREHOL_CONFIG_DIR}/firehol-defaults.conf" ]
then
	source "${FIREHOL_CONFIG_DIR}/firehol-defaults.conf" || exit 1
fi

# temporary variable (default LB_DEFAULT_IPV=4)
LB_IPV=

RUNNING_ON_TERMINAL=0
if [ "z$1" = "z-nc" ]
then
	shift
else
	common_setup_terminal && RUNNING_ON_TERMINAL=1
fi

# if called with the parameter 'boot', create a new screen that
# will run forever.
if [ "$1" = "boot" ]
then
	shift
	common_require_cmd $PROGRAM_FILE SCREEN_CMD
	$SCREEN_CMD -S 'link-balancer' -d -m "$0" loop "${@}"
	exit 0
fi

# if called with the parameter 'loop', run forever.
if [ "$1" = "loop" ]
then
	shift
	secs="${1}"
	secs=$[ secs + 1 - 1 ]
	test "${secs}" = "0" && secs=300
	shift

	while [ 1 ]
	do
		$0 "${@}"
		echo "Waiting for $secs secs..."
		$SLEEP_CMD $secs
	done
	exit 0
fi

if [ ! -d "${LB_RUN_DIR}" ]
then
	$MKDIR_CMD -p "${LB_RUN_DIR}" 	|| exit 1
	$CHOWN_CMD root:root "${LB_RUN_DIR}"	|| exit 1
	$CHMOD_CMD 700 "${LB_RUN_DIR}"	|| exit 1
fi

# get an exclusive lock or wait for it to be available
LOCKFILE="${LB_RUN_DIR}/link-balancer.lock"
[ "${FLOCKER}" != "${LOCKFILE}" ] && exec $ENV_CMD FLOCKER="${LOCKFILE}" $FLOCK_CMD -e "${LOCKFILE}" "$0" "$@" || :

cd "${LB_RUN_DIR}" || exit 1
LB_DIR="`$MKTEMP_CMD -d "${LB_RUN_DIR}/temp-XXXXXXXXXX"`" || exit 1


# -----------------------------------------------------------------------------
# Default FireHOL marks

declare -A MARKS_BITS='([connmark]="6" [usermark]="7" )'
declare -A MARKS_MASKS='([connmark]="0x0000003f" [usermark]="0x00001fc0" )'
declare -A MARKS_MAX='([connmark]="63" [usermark]="127" )'
declare -A MARKS_SHIFT='([connmark]="0" [usermark]="6" )'

FIREHOL_SPOOL_DIR="${FIREHOL_SPOOL_DIR-$LOCALSTATEDIR/spool/firehol}"
if [ -f "${FIREHOL_SPOOL_DIR}/marks.conf" ]
then
	source "${FIREHOL_SPOOL_DIR}/marks.conf" || exit 1
fi

mark_value() {
	local name="${1}"; shift
	local x=

	if [ -z "${name}" ]
	then
		error "Cannot find the value of mark with name '${name}'."
		return 1
	fi

	if [ -z "${1}" ]
	then
		error "Empty mark value given for mark ${name}."
		return 1
	fi

	if [ -z "${MARKS_MASKS[$name]}" ]
	then
		error "Mark $name does not exist."
		return 1
	fi

	for x in ${@//,/ }
	do
		local x=$[ x + 1 - 1 ]
		if [ $x -gt ${MARKS_MAX[$name]} -o $x -lt 0 ]
		then
			error "Cannot get mark $name of value $x. Mark $name is configured to get values from 0 to ${MARKS_MAX[$name]}. Change firehol-defaults.conf to add more."
			return 1
		fi

		#echo "$[ x << ${MARKS_SHIFT[$name]} ]/${MARKS_MASKS[$name]}"
		printf "0x%08x/${MARKS_MASKS[$name]}\n" "$[ x << ${MARKS_SHIFT[$name]} ]"
	done

	return 0
}

# -----------------------------------------------------------------------------

# Find in the BASH execution stack, the line and the source file that has called us.
# Before first use the variable PROGRAM_FILE should be set to the file to be excluded.
# It also sets the variable LAST_CONFIG_LINE on each run.
FORCE_CONFIG_LINEID=
LAST_CONFIG_LINE=
config_line() {
	if [ ! -z "${FORCE_CONFIG_LINEID}" ]
	then
		LAST_CONFIG_LINE="${FORCE_CONFIG_LINEID}"
	else
		# find the config line in the BASH stack
		# start from 2
		#   0 is this line
		#   1 is the caller - our line for sure
		#   2 is the caller's caller - possibly a config file line
		local i= all=${#BASH_SOURCE}
		for (( i = 2; i < $all; i++ ))
		do
			[ ! "${BASH_SOURCE[$i]}" = "${PROGRAM_FILE}" ] && break
		done
		LAST_CONFIG_LINE="${BASH_LINENO[$[i-1]]}@${BASH_SOURCE[$i]}: ${FUNCNAME[$[i-1]]}:"
	fi
	test ! "z$1" = "z-ne" && echo "${LAST_CONFIG_LINE}"
}

LB_RESULT_CODE=1
lb_exit() {
	cd /tmp

	if [ ${DEBUG_ALL_DATA} -eq 1 ]
	then
		echo >&2
		echo >&2
		echo >&2 "---------------------------------------------------------------------"
		echo >&2 "Temporary folder contents:"
		$LS_CMD -l "${LB_DIR}/" >&2

		for x in "${LB_DIR}"/*
		do
			echo >&2
			echo >&2
			echo >&2 "---------------------------------------------------------------------"
			echo >&2 "${x}"
			echo >&2 
			$CAT_CMD >&2 "${x}"
		done
	fi

	if [ ! -z "${LB_DIR}" -a -d "${LB_DIR}" ]
	then
		$RM_CMD -rf "${LB_DIR}"
	fi

	enable trap
	enable exit
	trap exit EXIT
	exit ${LB_RESULT_CODE}
}

trap lb_exit EXIT
trap lb_exit SIGHUP
trap lb_exit INT


# -----------------------------------------------------------------------------
# COMMON FUNCTIONS

syslog() {
	if [ ${DRY_RUN} -eq 0 ]
	then
		$LOGGER_CMD -p daemon.info -t "LinkBalancer" "${*}"
	fi
}

last_debug_depth=0
DEBUGCMDNNL() {
	local prefix="${1}"; shift
	local name="${1}"; shift
	local depth="${1}"; shift
	
	test "$depth" = "" && local depth=$last_debug_depth
	last_debug_depth=$depth

	# printf >&2 "`date`"
	printf >&2 "% $((depth))s ${prefix} %s " " " "${name}"
	printf >&2 " ${*} "
}

DEBUGCMD() {
	DEBUGCMDNNL "-" "${@}"
	printf >&2 "\n"
}

warning() {
	local line="$(config_line)"
	syslog "WARNING ${line} ${@}"

	echo >&2
	echo >&2 -e "${COLOR_YELLOW}${COLOR_BOLD}WARNING ${line} $@ ${COLOR_RESET}"
	echo >&2
	
	return 0
}

error() {
	local line="$(config_line)"
	syslog "ERROR ${line} ${@}"

	echo >&2
	echo >&2 -e "${COLOR_RED}${COLOR_BOLD}ERROR ${line} $@ ${COLOR_RESET}"
	echo >&2
	
	exit 1
}

run() {
	printf >&2 "${COLOR_BOLD}"
	DEBUGCMDNNL "#" "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}" " ... "

	local tmp="`$MKTEMP_CMD "${LB_DIR}/run-$$-${RANDOM}-XXXXXXXXXX"`"
	"${@}" >"$tmp" 2>"$tmp.err"
	local ret=$?

	if [ $ret -eq 0 ]
		then
		printf >&2 "${COLOR_RESET}${COLOR_BGGREEN}${COLOR_BLACK}${COLOR_BOLD} OK ${COLOR_RESET}\n"
	else
		printf >&2 "${COLOR_RESET}${COLOR_BGRED}${COLOR_WHITE}${COLOR_BOLD}${COLOR_BLINK} FAILED ${COLOR_RESET}\n"
	fi
	$CAT_CMD >&2 "$tmp.err"
	$CAT_CMD "$tmp"
	$RM_CMD "$tmp" "$tmp.err"
	return $ret
}

action() {
	if [ ${DRY_RUN} -eq 0 ]
		then
		printf >&2 "${COLOR_YELLOW}"
		run "${@}"
		local ret=$?

		if [ $ret -ne 0 ]
		then
			warning "Command: '${@}' exited with code $ret."
		else
			syslog "Successfuly run: '${@}'."
		fi

		return $ret
	fi

	DEBUGCMDNNL "#" "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}" " ... "
	printf >&2 "DEFERRED\n"
	return 0
}

trim_spaces() {
	$SED_CMD -e "s/[\t\\ ]\+/ /g" -e "s/ \+$//g" -e "s/^ \+//g"
}

loadfile() {
	local file="$1"; shift

	cd "${LB_CONFIG_DIR}"
	test ! -f "${file}" && syslog "WARNING: file '${file}' does not exist."
	$CAT_CMD "${file}" | $SED_CMD -e "s/#.*$//g" | trim_spaces | $TR_CMD '\n' ' '
	local ret=$?
	cd "${LB_RUN_DIR}"

	return $ret
}

ipv4() {
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	local cmd="${1}"; shift

	case "${cmd}" in
		gateway|table|rules|mark|fwmark|connmark|src|dst|from|to|tos|not)
			"${cmd}" ipv4 "${@}"
			return $?
			;;

		default)
			error "Command '${cmd}' inherits IP version from its parent. Do not give ${FUNCNAME} for '${cmd}'."
			exit 1
			;;

		*)
			error "Command '${cmd}' cannot change IP version."
			exit 1
			;;
	esac
}

ipv6() {
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	local cmd="${1}"; shift

	case "${cmd}" in
		gateway|table|rules|mark|fwmark|connmark|src|dst|from|to|tos|not)
			"${cmd}" ipv6 "${@}"
			return $?
			;;

		default)
			error "Command '${cmd}' inherits IP version from its parent. Do not give ${FUNCNAME} for '${cmd}'."
			exit 1
			;;

		*)
			error "Command '${cmd}' cannot change IP version."
			exit 1
			;;
	esac
}


# -----------------------------------------------------------------------------
# gateway section

get_interface_ips() {

	local ipv="4"
	test "${LB_IPV}" = "6" && local ipv="6"

	local inet="inet"
	test "${LB_IPV}" = "6" && local inet="inet6"


	run $IP_CMD -${ipv} addr show dev "$1" |\
		trim_spaces |\
		$GREP_CMD "${inet} " |\
		$CUT_CMD -d ' ' -f 2 |\
		$CUT_CMD -d '/' -f 1 |\
		$TR_CMD '\n' ' '
}

get_interface_routes() {
	local dev="${1}"; shift

	local ipv=4
	test "${LB_IPV}" = "6" && local ipv=6

	local hostnet="/32"
	test "${LB_IPV}" = "6" && local hostnet="/128"

	local i=
	for i in ${@}
	do
		run $IP_CMD -${ipv} route show dev "${dev}" scope link src "${i}" |\
			trim_spaces |\
			$CUT_CMD -d ' ' -f 1 |\
			$SED_CMD "s|/${hostnet}||g" |\
			$GREP_CMD -v "/" |\
			$TR_CMD '\n' ' '
	done
}

CHECK_PING_COUNT=3
CHECK_PING_WAIT=10
check_ping() {
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	
	local dev="$1"
	local src="$2"
	local dst="$3"
	
	local cmd="$PING_CMD"
	test "${LB_IPV}" = "6" && local cmd="$PING6_CMD"
	
	run $cmd -I ${src} -c ${CHECK_PING_COUNT} -w ${CHECK_PING_WAIT} ${dst} >/dev/null
	return $?
}

CHECK_TRACEROUTE_PORT=80
CHECK_TRACEROUTE_WAIT=2
check_traceroute() {
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	
	local dev="$1"
	local src="$2"
	local dst="$3"
	
	local cmd="$TRACEROUTE_CMD -4"
	test "${LB_IPV}" = "6" && local cmd="$TRACEROUTE_CMD -6"
	
	local found="`run $cmd -i "${dev}" -r -s ${src} -w ${CHECK_TRACEROUTE_WAIT} -Tn -p ${CHECK_TRACEROUTE_PORT} ${dst} | $GREP_CMD ${dst}`"
	test ! -z "${found}" && return 0
	return 1
}

check_alwayson() {
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	
	local dev="$1"
	local src="$2"
	local dst="$3"

	return 0
}

# this array has one entry per gateway.
# - the array index is the gateway name
# - the array value is the number of distinct gateways alive
declare -A LB_GATEWAYS=()

# keep track of the gateways IP version
declare -A LB_GATEWAYS_IPV=()

gateway4() { gateway ipv4 "${@}"; }
gateway6() { gateway ipv6 "${@}"; }
gateway() {
	printf >&2 "\n-------------------------------------------------------------------------------\n"
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	LB_IPV=${LB_DEFAULT_IPV}

	if [ ! -z "${work_route}" ]
	then
		local name="${work_route}"
	else
		local name="${1}"
		shift
	fi

	local gw=
	local dev=
	local src=
	local dst="gateway"
	local check="ping"

	while [ ! -z "${1}" ]
	do
		case "${1}" in
			ipv4)
				LB_IPV=4
				;;

			ipv6)
				LB_IPV=6
				;;

			on|dev)
				local dev="${2}"
				shift
				;;

			gateway|gw|via)
				local gw="${2//,/ }"
				shift
				;;

			src|from)
				local src="${2//,/ }"
				shift
				;;

			check)
				local check="${2}"
				local dst="${3//,/ }"
				shift 2
				;;

			*)
				error "${FUNCNAME} '${name}': cannot understand parameter '${1}'."
				return 1
				;;
		esac
		shift
	done

	LB_GATEWAYS[$name]=0
	LB_GATEWAYS_IPV[$name]=${LB_IPV}

	# if we don't have source IPs, find them from the interface
	if [ -z "${src}" -o "${src}" = "auto" ]
	then
		local src="`get_interface_ips "${dev}" | $SORT_CMD -u`"
	fi

	# if we don't have source IPs, cannot proceed
	if [ -z "${src}" ]
	then
		warning "Cannot find gateway ${name} IPs."
		return 1
	fi

	# if we don't have a gateway, cannot proceed
	if [ -z "${dev}" ]
	then
		error "${FUNCNAME} '${name}': cannot add a gateway without a device."
		return 2
	fi

	# if we don't have gateway IPs, find them from the interface
	test -z "${gw}" -o "${gw}" = "auto" -o "${gw}" = "detect" && local gw="`get_interface_routes "${dev}" ${src}`"

	# if we don't have a gateway, cannot proceed
	if [ -z "${gw}" ]
	then
		warning "Cannot find ${name} gateway IPs."
		return 3
	fi

	# if we don't have a destination, use the gateway	
	test -z "${dst}" -o "${dst}" = "auto" -o "${dst}" = "detect" -o "${dst}" = "gateway" && local dst="${gw}"
	test $FORCE_ALWAYSON -eq 1 && local check="alwayson"

	$CAT_CMD <<EOF_GW

    --- GATEWAY CONFIGURATION ----
    Gateway   : ${name}
    Via IP    : ${gw}
    Source IPs: ${src}
    Check     : ${check} ${dst}
    IP VERSION: ${LB_IPV}

EOF_GW

	echo "${src}" >"${LB_DIR}/gateway.${name}.source-ips"

	# -------------------------------------------------------------------------
	# Check if the gateway is alive

	echo "    CHECKING IF GATEWAY ${name} IS ALIVE"

	local alive=0
	local s=
	for s in ${src}
	do
		local d=
		for d in ${dst}
		do
			test $alive -ne 0 && break

			check_${check} ${dev} ${s} ${d}
			test $? -eq 0 && local alive=1
		done
	done

	if [ ${alive} -eq 0 ]
	then
		echo
		echo "    Gateway ${name} is not alive."
		return 99
	fi

	local count=0
	local g=
	for g in ${gw}
	do
		local count=$[count + 1]
		echo "via ${g} dev ${dev}" >>"${LB_DIR}/gateway.${name}.paths"
	done

	LB_GATEWAYS[$name]="${count}"

	echo >&2 
	echo >&2 -e "    ${COLOR_GREEN}${COLOR_BOLD}IPv${LB_IPV} gateway '${name}' is alive, having ${count} active path(s).${COLOR_RESET}"
	return 0
}


# -----------------------------------------------------------------------------
# table section

# this array has one entry per table.
# - the array index is the table name
# - the array value is the number of default gateways available
declare -A LB_TABLES=()
declare -A LB_TABLES_FALLBACK=()

# keep track of the IP version per table
# if a table is used by both IPv4 and IPv6, '46' should be stored
declare -A LB_TABLES_IPV=()

# keep track of all origin tables
# if a table is used by both IPv4 and IPv6, '46' should be stored
declare -A LB_ORIGIN_TABLES=()

get_existing_routing_table() {
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	
	local table="${1}"

	if [ "${LB_IPV}" = "6" ]
	then
		run $IP_CMD -6 -o route show table "${table}" |\
			trim_spaces |\
			$SORT_CMD
	else
		run $IP_CMD -4 -o route show table "${table}" |\
			$GREP_CMD -v " via 127.0.0.1 dev lo" |\
			trim_spaces |\
			$SORT_CMD
	fi
}

work_table=
work_ipv=
table4() { table ipv4 "${@}"; }
table6() { table ipv6 "${@}"; }
table() {
	printf >&2 "\n-------------------------------------------------------------------------------\n"
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	LB_IPV=${LB_DEFAULT_IPV}

	local table="$1"; shift

	if [ -z "${table}" ]
	then
		error "${FUNCNAME} needs a name."
		return 1
	fi

	local origin="main"
	local copy_default=1
	while [ ! -z "${1}" ]
	do
		case "${1}" in
			ipv4)
				LB_IPV=4
				;;

			ipv6)
				LB_IPV=6
				;;

			from|copy|duplicate)
				local origin="${2}"
				shift
				;;

			nodefault|keepdefault|nodef)
				local copy_default=0
				;;

			*)
				error "${FUNCNAME} '${table}': Cannot understand option '${1}'."
				return 1
				;;
		esac
		shift
	done

	# set LB_TABLES_IPV
	if [ -z "${LB_TABLES_IPV[$table]}" ]
	then
		LB_TABLES_IPV[$table]="${LB_IPV}"
	elif [ "${LB_TABLES_IPV[$table]}" = "${LB_IPV}" ]
	then
		error "${FUNCNAME}: table ${table} already exists in IPv${LB_IPV}."
		exit 1
	else
		LB_TABLES_IPV[$table]="46"
	fi

	if [ "${table}" = "${origin}" -o -z "${origin}" -o "${origin}" = "none" ]
	then
		local origin="none"
	fi

	# give a summary to the user
	$CAT_CMD <<EOF_TABLE

    --- TABLE CONFIGURATION ---
    Table       : ${table}
    Copy from   : ${origin}
    IP VERSION  : ${LB_IPV}

EOF_TABLE

	if [ ! "${origin}" = "none" ]
	then
		# just link it
		# The source file may not exist yet. This is OK.
		# Later, at finizize_tables() we will check the links to find
		# the dependencies between the tables so that they will be
		# activated in the correct order, so that in one pass all
		# tables will get the final routes.
		# We will also check if the user requested a circular
		# dependency, and stop processing in this case.
		$LN_CMD -s "${LB_DIR}/table.${origin}.routes.${LB_IPV}" "${LB_DIR}/table.${table}.origin_routes.${LB_IPV}"
		test $copy_default -eq 1 && $LN_CMD -s "${LB_DIR}/table.${origin}.default.${LB_IPV}" "${LB_DIR}/table.${table}.origin_default.${LB_IPV}"
	fi

	work_table="${table}"
	work_ipv="${LB_IPV}"
	LB_TABLES[$table]=0
	LB_TABLES_FALLBACK[$table]=0

	if [ ! "${origin}" = "none" ]
	then
		# set LB_ORIGIN_TABLES
		if [ -z "${LB_ORIGIN_TABLES[$origin]}" ]
		then
			LB_ORIGIN_TABLES[$origin]="${LB_IPV}"
		elif [ ! "${LB_ORIGIN_TABLES[$origin]}" = "${LB_IPV}" ]
		then
			LB_ORIGIN_TABLES[$origin]="46"
		fi
	fi

	# instruct the finalizer to run IPvX tables
	$TOUCH_CMD "${LB_DIR}/tables.${LB_IPV}"
}

fallback() {
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	default "${@}" weight 0
}

default() {
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"

	if [ -z "${work_table}" ]
	then
		error "Statement 'default' should appear after a 'table'."
		exit 1
	fi

	# check IPvX is as it should
	LB_IPV=${work_ipv}
	if [ ! "${LB_TABLES_IPV[${work_table}]}" = "${LB_IPV}" -a ! "${LB_TABLES_IPV[${work_table}]}" = "46" ]
	then
		error "${FUNCNAME} INTERNAL ERROR: Inheritted IPv${LB_IPV} but table is IPv${LB_TABLES_IPV[${work_table}]}."
		exit 1
	fi

	local gw=
	local weight=100
	while [ ! -z "${1}" ]
	do
		case "${1}" in
			via|gateway|gw)
				gw="${2}"
				shift
				;;

			weight)
				local weight="${2}"
				shift
				;;

			*)
				error "${FUNCNAME} on '${work_table}': Cannot understand option '${1}'."
				return 1
				;;
		esac
		shift
	done

	if [ -z "${gw}" ]
	then
		error "${FUNCNAME} on '${work_table}': Cannot work without a gateway."
		return 1
	fi

	if [ -z "${LB_GATEWAYS[$gw]}" ]
	then
		warning "'${gw}' on '${work_table}': Unknown gateway '${gw}' requested."
		return 1
	fi

	if [ ! "${LB_GATEWAYS_IPV[$gw]}" = "${LB_IPV}" ]
	then
		error "${FUNCNAME} '${gw}' on '${work_table}': Cannot assign an IPv${LB_GATEWAYS_IPV[$gw]} gateway to an IPv${LB_IPV} table."
		exit 1
	fi

	if [ "${LB_GATEWAYS[$gw]}" = "0" ]
	then
		warning "'${gw}' on '${work_table}': Ignoring gateway '${gw}', it is not alive."
		return 1
	fi

	if [ ! -s "${LB_DIR}/gateway.${gw}.paths" ]
	then
		warning "'${gw}' on '${work_table}': Gateway '${gw}' does not have any routes."
		return 1
	fi

	local context="default"
	if [ "${weight}" = "0" ]
	then
		local context="fallback"
		local weight="100"
		local count=${LB_TABLES_FALLBACK[${work_table}]}
	else
		local count=${LB_TABLES[${work_table}]}
	fi

	while read
	do
		count=$[count + 1]
		echo "nexthop ${REPLY} weight ${weight}" >>"${LB_DIR}/table.${work_table}.${context}.${LB_IPV}"
	done <"${LB_DIR}/gateway.${gw}.paths"
	
	if [ "${context}" = "default" ]
	then
		LB_TABLES[${work_table}]=$count
	else
		LB_TABLES_FALLBACK[${work_table}]=$count
	fi
}

lb_diff_route() {
	local cmd="$1"; shift
	local table="$1"; shift

	case "${cmd}" in
		add)
			action $IP_CMD -${LB_IPV} route add table ${table} "${@}" || action $IP_CMD -${LB_IPV} route append table ${table} "${@}"
			return $?
			;;

		delete)
			action $IP_CMD -${LB_IPV} route del table ${table} "${@}"
			return $?
			;;

		same)
			return 0
			;;
	esac
	return 1
}

update_table() {
	printf >&2 "\n    -----------------------------------------------\n"
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"

	LB_IPV="${1}"; shift
	local table="${1}"; shift

	# check IPvX is as it should
	if [ ! "${LB_TABLES_IPV[${table}]}" = "${LB_IPV}" -a ! "${LB_TABLES_IPV[${table}]}" = "46" ]
	then
		error "${FUNCNAME} INTERNAL ERROR: Inheritted IPv${LB_IPV} but table is IPv${LB_TABLES_IPV[${work_table}]}."
		exit 1
	fi

	# ---------------------------------------------------------------------
	# unit testing - make sure it works right

	if [ -h "${LB_DIR}/table.${table}.origin_routes.${LB_IPV}" -a ! -f "${LB_DIR}/table.${table}.origin_routes.${LB_IPV}" ]
	then
		error "INTERNAL ERROR: table.${table}.origin_routes.${LB_IPV} is an unresolvable link!"
		exit 1
	fi

	if [ -h "${LB_DIR}/table.${table}.origin_default.${LB_IPV}" -a ! -f "${LB_DIR}/table.${table}.origin_default.${LB_IPV}" ]
	then
		error "INTERNAL ERROR: table.${table}.origin_default.${LB_IPV} is an unresolvable link!"
		exit 1
	fi


	# ---------------------------------------------------------------------
	# decide what will be done for this table

	# 1. if 'table.${table}.origin_routes' exists, we copy the routing table
	# 2. if 'table.${table}.default' or 'table.${table}.origin_default' exist, we set the default gateway
	# 3. if none of the above is present, we do nothing

	local routing_filter_cmd="$CAT_CMD"
	if [ -f "${LB_DIR}/table.${table}.origin_routes.${LB_IPV}" -a \( -f "${LB_DIR}/table.${table}.default.${LB_IPV}" -o -f "${LB_DIR}/table.${table}.fallback.${LB_IPV}" -o -f "${LB_DIR}/table.${table}.origin_default.${LB_IPV}" \) ]
	then
		# we do both routes copy and set default gateway
		routing_filter_cmd="$CAT_CMD"

	elif [ -f "${LB_DIR}/table.${table}.default.${LB_IPV}" -o -f "${LB_DIR}/table.${table}.origin_default.${LB_IPV}" ]
	then
		# we should only process default gateway
		routing_filter_cmd="$GREP_CMD ^default"

	elif [ -f "${LB_DIR}/table.${table}.origin_routes.${LB_IPV}" ]
	then
		# we should only copy the routing table without the default gateway
		routing_filter_cmd="$GREP_CMD -v ^default"

	else
		# process both routes and default gateway
		routing_filter_cmd="$CAT_CMD"

		# commented due to issue 78
		# nothing to be done - just return
		#echo >&2 -e "    ${COLOR_GREEN}${COLOR_BOLD}Nothing to be done for table ${table}${COLOR_RESET}"
		#return 0
	fi


	# ---------------------------------------------------------------------
	# get the existing routing table

	get_existing_routing_table "${table}" >"${LB_DIR}/table.${table}.existing_routing_table.${LB_IPV}"

	# if we don't have origin, assume the existing is the origin
	if [ ! -f "${LB_DIR}/table.${table}.origin_routes.${LB_IPV}" ]
	then
		$CAT_CMD "${LB_DIR}/table.${table}.existing_routing_table.${LB_IPV}" |\
			$GREP_CMD -v ^default >"${LB_DIR}/table.${table}.origin_routes.${LB_IPV}"
	fi

	if [ ! -f "${LB_DIR}/table.${table}.origin_default.${LB_IPV}" ]
	then
		$CAT_CMD "${LB_DIR}/table.${table}.existing_routing_table.${LB_IPV}" |\
			$GREP_CMD -v ^default >"${LB_DIR}/table.${table}.origin_default.${LB_IPV}"
	fi

	$CAT_CMD "${LB_DIR}/table.${table}.existing_routing_table.${LB_IPV}" |\
		${routing_filter_cmd} >"${LB_DIR}/table.${table}.existing_routes.${LB_IPV}"


	# ---------------------------------------------------------------------
	# generate the new routing table

	local context="default"
	local gateways=${LB_TABLES[${table}]}
	if [ ${gateways} -eq 0 ]
	then
		# there are no active gateways
		# do we have a fallback?
		if [ ${LB_TABLES_FALLBACK[${table}]} -gt 0 ]
		then
			# we have a fallback
			local gateways=${LB_TABLES_FALLBACK[${table}]}
			local context="fallback"

			echo >&2 "   USING fallback gateways!"
			syslog "Using fallback gateways for table ${table}."
		fi
	fi

	(
		$CAT_CMD "${LB_DIR}/table.${table}.origin_routes.${LB_IPV}"

		if [ ${gateways} -eq 0 ]
		then
			# we don't have a gateway alive
			# copy the origin default gateway, if we have to
			$CAT_CMD "${LB_DIR}/table.${table}.origin_default.${LB_IPV}"

		elif [ ${gateways} -eq 1 ]
		then
			# we only have one gateway alive

			printf "default "
			$CAT_CMD "${LB_DIR}/table.${table}.${context}.${LB_IPV}" |\
				$SED_CMD -e "s/nexthop //g" -e "s/ weight [0-9]\+//g"

		else
			# we have many (2+) gateways alive

			printf "default "
			$CAT_CMD "${LB_DIR}/table.${table}.${context}.${LB_IPV}" |\
				$TR_CMD '\n' ' '

		fi
	) | trim_spaces |\
		$SORT_CMD -u >"${LB_DIR}/table.${table}.new_routing_table.${LB_IPV}"

	# keep the new routes of our dependands
	$CAT_CMD "${LB_DIR}/table.${table}.new_routing_table.${LB_IPV}" |\
		$GREP_CMD -v ^default >"${LB_DIR}/table.${table}.routes.${LB_IPV}"

	$CAT_CMD "${LB_DIR}/table.${table}.new_routing_table.${LB_IPV}" |\
		$GREP_CMD ^default >"${LB_DIR}/table.${table}.default.${LB_IPV}"

	# generate the new routing table for diff
	$CAT_CMD "${LB_DIR}/table.${table}.new_routing_table.${LB_IPV}" |\
		${routing_filter_cmd} >"${LB_DIR}/table.${table}.new_routes.${LB_IPV}"

	# ---------------------------------------------------------------------
	# diff magic...
	# generate a script to process the diffs of the two files

	#echo "EXISTING"
	#cat "${LB_DIR}/table.${table}.existing_routes.${LB_IPV}"
	#echo "NEW filter: ${routing_filter_cmd}"
	#cat "${LB_DIR}/table.${table}.new_routes.${LB_IPV}"

	$DIFF_CMD >"${LB_DIR}/table.${table}.script.${LB_IPV}"			\
		--old-line-format="lb_diff_route delete ${table} %L" 		\
		--new-line-format="lb_diff_route add ${table} %L" 		\
		--unchanged-line-format="lb_diff_route same ${table} %L" 	\
		"${LB_DIR}/table.${table}.existing_routes.${LB_IPV}"		\
		"${LB_DIR}/table.${table}.new_routes.${LB_IPV}"

	if [ $? -eq 1 ]
	then
		source "${LB_DIR}/table.${table}.script.${LB_IPV}"
		LB_ALTERED[table.${table}]=1

		local def=0
		test ! -z "`$GREP_CMD " default " "${LB_DIR}/table.${table}.script.${LB_IPV}"`" && def=1
		
		echo >&2 
		echo >&2 -e "    ${COLOR_YELLOW}${COLOR_BOLD}Updated routing table ${table}!${COLOR_RESET}"

		updated_routes "${table}" "${def}"
	else
		echo >&2 
		echo >&2 -e "    ${COLOR_GREEN}${COLOR_BOLD}Table's ${table} routing is already as it should.${COLOR_RESET}"
		echo >&2 
	fi
}

finalize_tables() {
	printf >&2 "\n-------------------------------------------------------------------------------\n"
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"

	LB_IPV="${1}"
	if [ -z "${LB_IPV}" ]
	then
		error "INTERNAL ERROR: Detected empty LB_IPV."
		exit 1
	fi

	# put all the tables in this variable
	local -A all=()
	local x=
	for x in "${!LB_ORIGIN_TABLES[@]}"
	do
		test "${LB_ORIGIN_TABLES[$x]}" = "${LB_IPV}" -o "${LB_ORIGIN_TABLES[$x]}" = "46" && all[$x]=1
	done
	for x in "${!LB_TABLES[@]}"
	do
		test "${LB_TABLES_IPV[$x]}" = "${LB_IPV}" -o "${LB_TABLES_IPV[$x]}" = "46" && all[$x]=1
	done

	# execute the tables with circular dependency check
	while [ "${#all[@]}" -ne 0 ]
	do
		local found=0
		for x in "${!all[@]}"
		do
			printf >&2 "\n     > Checking dependency for IPv${LB_IPV} table ${x}... "

			if [ ! -h "${LB_DIR}/table.${x}.origin_routes.${LB_IPV}" -o -f "${LB_DIR}/table.${x}.origin_routes.${LB_IPV}" ]
			then
				if [ ! -z "${LB_TABLES[$x]}" ]
				then
					printf >&2 "READY!\n"
					update_table "${LB_IPV}" "${x}"
				else
					printf >&2 "ORIGIN ONLY\n"

					get_existing_routing_table "${x}" >"${LB_DIR}/table.${x}.existing_routing_table.${LB_IPV}" || exit 1

					$CAT_CMD "${LB_DIR}/table.${x}.existing_routing_table" |\
						$GREP_CMD -v ^default >"${LB_DIR}/table.${x}.routes.${LB_IPV}"

					$CAT_CMD "${LB_DIR}/table.${x}.existing_routing_table" |\
						$GREP_CMD ^default >"${LB_DIR}/table.${x}.default.${LB_IPV}"
				fi

				unset all[$x]
				local found=1
				break
			else
				printf >&2 "NOT READY\n"
			fi
		done
		
		if [ $found -eq 0 ]
		then
			error "CIRCULAR DEPENDENCY among the tables detected."
			exit 1
		fi
	done
}

# this is to overwritten by the caller
# it is called only when routing rules are updated (added/removed)
updated_routes() {
	local table="${1}"
	local def="${2}" # if this is 1, the default route has been updated

	return 0
}

# -----------------------------------------------------------------------------
# policy based routing - rules section

LB_DO_RULES_IPV4=0
LB_DO_RULES_IPV6=0
LB_RULES_DEFAULT_IPV=${LB_DEFAULT_IPV}

policy4() { policy ipv4 "${@}"; }
policy6() { policy ipv6 "${@}"; }
policy() {
	printf >&2 "\n-------------------------------------------------------------------------------\n"
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	LB_RULES_DEFAULT_IPV=${LB_DEFAULT_IPV}

	while [ ! -z "${1}" ]
	do
		case "${1}" in
			ipv4)
				LB_RULES_DEFAULT_IPV=4
				;;

			ipv6)
				LB_RULES_DEFAULT_IPV=6
				;;

			*)
				error "${FUNCNAME}: Cannot understand option '${1}'."
				exit 1
				;;
		esac
		shift
	done

	if [ "${LB_RULES_DEFAULT_IPV}" = "6" ]
	then
		LB_DO_RULES_IPV6=1
	else
		LB_DO_RULES_IPV4=1
	fi
	$TOUCH_CMD "${LB_DIR}/rules.${LB_RULES_DEFAULT_IPV}"
}

LB_RULE_BASE4=1000
LB_RULE_BASE6=1000

rules4() { rules ipv4 "${@}"; }
rules6() { rules ipv6 "${@}"; }
rules() {
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"
	LB_IPV=${LB_RULES_DEFAULT_IPV}

	local -a tos=()
	local -a mark=()
	local -a src=()
	local -a dst=()
	local -a inface=()

	local marktype=

	local action=
	local table=
	local not=
	local cmd=
	while [ ! -z "${1}" ]
	do
		case "${1}" in
			ipv4)
				LB_IPV=4
				LB_DO_RULES_IPV4=1
				$TOUCH_CMD "${LB_DIR}/rules.${LB_IPV}"
				;;

			ipv6)
				LB_IPV=6
				LB_DO_RULES_IPV6=1
				$TOUCH_CMD "${LB_DIR}/rules.${LB_IPV}"
				;;

			at|lookup|table)
				local action="lookup ${2}"
				local table="${2}"
				shift
				;;

			# nat) # this converts the rule to 'masquerade' and gives a warning it is deprecated

			prohibit|unreachable) # 'reject' gives: Error: argument "reject" is wrong: Failed to parse rule type
				local action="${1}"
				;;

			rawmark)
				local marktype=
				local cmd="mark"
				;;

			mark)
				local marktype="usermark"
				local cmd="mark"
				;;

			custommark)
				local marktype="${2}"; shift
				local cmd="mark"
				if [ -z "${MARKS_MASKS[$marktype]}" ]
				then
					error "Mark type '${marktype}' is not defined."
					exit 1
				fi
				;;

			connmark)
				local marktype="connmark"
				local cmd="mark"
				;;

			src|from)
				local cmd="src"
				;;
			
			inface|iif)
				local cmd="inface"
				;;

			dst|to)
				local cmd="dst"
				;;
			
			tos)
				local cmd="tos"
				;;

			not)
				local not="not"
				;;

			gw-src-ips)
				local x=${2}; shift
				if [ -z "${LB_GATEWAYS[$x]}" ]
				then
					error "Cannot find gateway '${x}'."
					exit 1
				fi
				if [ ! "${LB_GATEWAYS_IPV[$x]}" = "${LB_IPV}" ]
				then
					error "Cannot add IPv${LB_GATEWAYS_IPV[$x]} gateway source IPs to IPv${LB_IPV} rules."
					exit 1
				fi
				if [ "${LB_GATEWAYS[$x]}" -eq 0 ]
				then
					warning "Ignoring rules for gateway '${x}'. Gateway '${x}' is not alive."
				else
					src+=(`loadfile "${LB_DIR}/gateway.${x}.source-ips"`)
				fi
				;;

			loadfile)
				case "${cmd}" in
					src) src+=(`loadfile "${2}"`);;
					dst) dst+=(`loadfile "${2}"`);;
				esac
				shift
				;;

			*)
				case "${cmd}" in
					mark)
						if [ -z "${marktype}" ]
						then
							mark+=( ${1//,/ } )
						else
							mark+=( $(mark_value $marktype ${1//,/ }) )
						fi
						;;

					tos) tos+=( ${1//,/ } );;
					src) src+=( ${1//,/ } );;
					dst) dst+=( ${1//,/ } );;
					inface) inface+=( ${1//,/ } );;
				esac
				;;
		esac
		shift
	done

	local base=
	if [ "${LB_IPV}" = "6" ]
	then
		local base=${LB_RULE_BASE6}
		LB_DO_RULES_IPV6=1
	else 
		local base=${LB_RULE_BASE4}
		LB_DO_RULES_IPV4=1
	fi
	$TOUCH_CMD "${LB_DIR}/rules.${LB_IPV}"

	# give some space between rules
	base=$[ ( (base + LB_RULE_STEP) / LB_RULE_STEP ) * LB_RULE_STEP ]

	# put it back, in case we return before the end
	if [ "${LB_IPV}" = "6" ]
	then
		LB_RULE_BASE6=${base}
	else 
		LB_RULE_BASE4=${base}
	fi

	if [ "${#mark[*]}${#tos[*]}${#src[*]}${#dst[*]}${#inface[*]}" = "00000" ]
	then
		warning "No rules generated."
		return 0
	fi

	if [ ! -z "${table}" ]
	then
		if [ -z "${LB_TABLES[$table]}" ]
		then
			error "${FUNCNAME}: table $table does not exist."
			exit 1
		fi
	fi

	test ${#mark[@]} -eq 0 && mark=('any')
	test ${#tos[@]} -eq 0 && tos=('any')
	test ${#src[@]} -eq 0 && src=('any')
	test ${#dst[@]} -eq 0 && dst=('any')
	test ${#inface[@]} -eq 0 && inface=('any')

	local m=
	local t=
	local s=
	local d=
	local i=
	for m in ${mark[@]}
	do
		test "${m}" = "any" && local m=
		test ! -z "${m}" && local m="fwmark ${m}"

		for t in ${tos[@]}
		do
			test "${t}" = "any" && local t=
			test ! -z "${t}" && local t="tos ${t}"

			for i in ${inface[@]}
			do
				test "${i}" = "any" && local i=
				test ! -z "${i}" && local d="iif ${i}"

				for s in ${src[@]}
				do
					test "${s}" = "any" && local s="all"
					test ! -z "${s}" && local s="from ${s}"

					for d in ${dst[@]}
					do
						test "${d}" = "any" && local d=
						test ! -z "${d}" && local d="to ${d}"

						echo "priority ${base} ${not} ${s} ${d} ${t} ${m} ${i} ${action}" >>"${LB_DIR}/rules.${LB_IPV}"
						base=$[base + 1]
					done
				done
			done
		done
	done

	# put the priority back to the global variable
	if [ "${LB_IPV}" = "6" ]
	then
		LB_RULE_BASE6=${base}
	else 
		LB_RULE_BASE4=${base}
	fi
}

mark() { rules ${FUNCNAME} "${@}"; }
fwmark() { rules ${FUNCNAME} "${@}"; }
connmark() { rules ${FUNCNAME} "${@}"; }
custommark() { rules ${FUNCNAME} "${@}"; }
rawmark() { rules ${FUNCNAME} "${@}"; }
src() { rules ${FUNCNAME} "${@}"; }
dst() { rules ${FUNCNAME} "${@}"; }
from() { rules ${FUNCNAME} "${@}"; }
to() { rules ${FUNCNAME} "${@}"; }
tos() { rules ${FUNCNAME} "${@}"; }
not() { rules ${FUNCNAME} "${@}"; }

# function to be called by the diff generated script
lb_diff_rule() {
	local cmd="$1"; shift

	case "${cmd}" in
		add)
			action $IP_CMD -${LB_IPV} rule add "${@}"
			return $?
			;;

		delete)
			action $IP_CMD -${LB_IPV} rule del "${@}"
			return $?
			;;

		same)
			return 0
			;;
	esac
	return 1
}

normalize_rules() {
	$SED_CMD -e "s| fwmark 0x\([0-9a-fA-F]\)\([ /]\)| fwmark 0x0\1\2|g" \
		-e "s| tos 0x\([0-9a-fA-F]\) | tos 0x0\1|g" \
		-e "s| tos 0x02 | tos mincost |g" \
		-e "s| tos 0x04 | tos reliability |g" \
		-e "s| tos 0x08 | tos throughput |g" \
		-e "s| tos 0x0a | tos lowdelay |g" \
		-e "s| tos 2 | tos mincost |g" \
		-e "s| tos 4 | tos reliability |g" \
		-e "s| tos 8 | tos throughput |g" \
		-e "s| tos 10 | tos lowdelay |g" \
		-e "s|0x0\+|0x|g"
}

finalize_rules() {
	printf >&2 "\n-------------------------------------------------------------------------------\n"
	DEBUGCMD "${FUNCNAME}" "${#FUNCNAME[*]}" "${@}"

	LB_IPV="${1}"
	if [ -z "${LB_IPV}" ]
	then
		error "INTERNAL ERROR: Detected empty LB_IPV."
		exit 1
	fi

	# copy the tables and remove 'main' from it
	local string=$(declare -p LB_TABLES)
	eval "local -A tables=${string#*=}"
	unset tables[main]

	# get all the rules for all the tables except 'main'
	run $IP_CMD -${LB_IPV} rule show |\
		trim_spaces |\
		$EGREP_CMD -v "^(0|32766|32767)" |\
		$SED_CMD "s/\(^[0-9]\+\): /priority \1 /g" |\
		normalize_rules |\
		$SORT_CMD >"${LB_DIR}/rules.existing.${LB_IPV}"

	# fix the generated rules, from the rules()
	$CAT_CMD "${LB_DIR}/rules.${LB_IPV}" |\
		trim_spaces |\
		normalize_rules |\
		$SORT_CMD -u >"${LB_DIR}/rules.new.${LB_IPV}"

	# diff magic...
	# generate a script to process the diffs of the two files
	$DIFF_CMD >"${LB_DIR}/rules.script.${LB_IPV}"				\
		--old-line-format="lb_diff_rule delete ${table} %L" 		\
		--new-line-format="lb_diff_rule add ${table} %L" 		\
		--unchanged-line-format="lb_diff_rule same ${table} %L" 	\
		"${LB_DIR}/rules.existing.${LB_IPV}"				\
		"${LB_DIR}/rules.new.${LB_IPV}"

	if [ $? -eq 1 ]
	then
		source "${LB_DIR}/rules.script.${LB_IPV}"
		LB_ALTERED[routing.rules.ipv${LB_IPV}]=1

		echo >&2 
		echo >&2 -e "    ${COLOR_YELLOW}${COLOR_BOLD}Updated IPv${LB_IPV} routing rules!${COLOR_RESET}"

		updated_rules
	else
		echo >&2 
		echo >&2 -e "    ${COLOR_GREEN}${COLOR_BOLD}Nothing to be done for IPv${LB_IPV} routing rules.${COLOR_RESET}"
	fi
}

# this is to overwritten by the caller
# it is called only when routing rules are updated (added/removed)
updated_rules() {
	return 0
}

# -----------------------------------------------------------------------------
# other functions

# this tries to find all the IPs of an Autonomous System (AS).
# 1. it requires an IP from the caller.
# 2. it queries whois for this IP to find its AS.
# 3. it queries RIPE to get all the IP address space for this AS.
asips() {
	common_require_cmd $PROGRAM_FILE WHOIS_CMD
	common_require_cmd $PROGRAM_FILE JQ_CMD
	common_require_cmd $PROGRAM_FILE HEAD_CMD
	common_require_cmd $PROGRAM_FILE WGET_CMD

	local ip="${1}"

	if [ -z "${ip}" ]
	then
		echo >&2 "${FUNCNAME} requires an IP address."
		echo >&2 "Commands: 'whois' and 'jq' have to be installed for this to work."
		return 1
	fi

	echo >&2 
	echo >&2 "Querying whois for IP ${ip}..."
	local as="`$WHOIS_CMD "${1}" | $GREP_CMD "origin:" | trim_spaces | $CUT_CMD -d ' ' -f 2 | $GREP_CMD ^AS | $HEAD_CMD -n 1`"
	if [ -z "${as}" ]
	then
		echo >&2 "Cannot find the Autonomous System of IP '${ip}'."
		return 1
	fi
	echo >&2 "IP ${ip} is part of Autonomous System: ${as}."

	echo >&2
	echo >&2 "Querying RIPE for ${as}..."
	$WGET_CMD -O - "https://stat.ripe.net/data/as-routing-consistency/data.json?resource=${as}" |\
		$JQ_CMD .data.prefixes[].prefix |\
		$SED_CMD -e 's| ||g' -e 's|"||g' |\
		$EGREP_CMD "^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+/[0-9]+" |\
		$IPRANGE_CMD
}

# -----------------------------------------------------------------------------
# help

emit_version() {
	$CAT_CMD <<EOF

FireHOL LinkBalancer $VERSION
(C) Copyright 2015 Costa Tsaousis <costa@tsaousis.gr>
(C) Copyright 2015 Phil Whineray <phil@firehol.org>
FireHOL is distributed under the GPL v2+.
Home Page: http://firehol.org

-------------------------------------------------------------------------
Get notified of new FireHOL releases by subscribing to the mailing list:
    http://lists.firehol.org/mailman/listinfo/firehol-support/
-------------------------------------------------------------------------

EOF
}


help() {

$CAT_CMD <<EOFHELP
Modes:

   ${PROGRAM_FILE} boot [seconds]

     - default 'seconds' is 300 (run every 5 mins)

   Runs LinkBalancer in a screen session in the background.
   To see it running run: 'screen -r link-balancer'
   To exit screen without stopping it, press: Control-a then d.


   ${PROGRAM_FILE} loop [seconds]

   like above, but run in foreground, not in a screen session.


   ${PROGRAM_FILE} -h|--help

   Present this help file.


   ${PROGRAM_FILE} [-t|--test] [-f|--fast] [-d|--debug]

    -t or --test

    Do not alter anything on the system.
    Just show what would have been done.

    -f or --fast

    Assume all gateways are up, if their interfaces are up.
    This should be run from '/etc/ppp/ip-down' to quickly
    restore the default gateways of the system.

    -d or --debug

    At the end of the execution, output all temporary
    files.

EOFHELP

$CAT_CMD >"${LB_CONFIG}.example" <<EOFCONFIG
# Link Balancer Configuration file

# default is IPv4.
# You can change the default to IPv6 by setting this to "6":
LB_DEFAULT_IPV="4"

# You can also specify IPv4 or IPv6 for gateways, tables and policy by
# using gateway4 gateway6 table4 table6 policy4 policy6
# If you use these without the number, the default above will be used.
# You can also run 'ipv4 gateway ...' or 'ipv4 gateway ...'
# for all these statements.

# -----------------------------------------------------------------------------
# define all the gateways

# TEMPLATE:
#
# gateway GATEWAY_NAME dev DEVICE [gw "IPs"] [src "IPs"] [check METHOD "IPs" ]
#
#  - DEVICE is the interface via which the gateway is accessible
#  - gw IP is autodetected if not given
#  - src IP is autodetected if not given
#  - METHODs: ping traceroute alwayson (default is ping)
#  - when check IPs is empty the gw IPs are used
#
# In general
# - for point to point PPP interfaces everything is autodetected
# - for point to lan PPP interfaces, you have to give gw IP and src IP
# - for eth devices you have to specify the gw IP
#
# Hint: If you use PPP devices, specify in the peers file of pppd the
# unit number you want it to use. This way, you will know that, for example,
# you office VPN is always at ppp14.
# Another way is to rename the ppp device in /etc/ppp/ip-up, so that
# instead of having 'ppp14', you will have the interface as 'work1'.
#
# examples:

# wan providers
gateway dsl1 dev ppp11
gateway dsl2 dev eth3 gw 2.2.2.2
gateway dsl3 dev eth4 gw 3.3.3.3

# dual path office VPN
gateway work1 dev ppp14 check 172.16.1.2
gateway work2 dev tun0 check 172.16.1.4


# -----------------------------------------------------------------------------
# define all the routing tables

# Tables can be defined using numbers from 1 to 252.
# Do not use tables 0, 253, 254 and 255. They are system tables.

# You can give names to tables by editing /etc/iproute2/rt_tables
# If you give names, you can use them here.

# TEMPLATE:
#
# table NAME [from ORIGIN_TABLE_NAME] [nodefault]
#
# - NAME and ORIGIN_TABLE_NAME can either be IDs or names
# - The default ORIGIN_TABLE_NAME is: main
# - nodefault means in case the table is left without a default gateway,
#   do not copy the default gateway of the ORIGIN_TABLE_NAME
#
# then for each table, define the default gateways you want:
#
#       default via GATEWAY_NAME [weight 0-250]
#
# - GATEWAY_NAME is the name of the gateway as given in the gateways section.
# - default weight is 100. Weights can be given as 0 to 255.
# - weight 0 is special. It means don't use this unless there is no
#   other gateway available.
# 
# you can add as many default gateways per table, as you need.
#
# You should define one table per gateway and one for load-balancing the
# gateways. You need one table per gateway, so that if you receive requests
# from the gateways, you will respond to these requests via the same path.
# 
# examples:

# one table per WAN gateway
table dsl1
	default via dsl1

table dsl2
	default via dsl2

table dsl3
	default via dsl3

# this is the main system routing table
table main
	default via dsl1 weigth 250
	default via dsl2 weight 150
	default via dsl3 weight 50


# one table per WORK gateway
table work1 from WORK # we copy WORK here, not 'main'
	default via work1

table work2 from WORK # we copy WORK here, not 'main'
	default via work2

# this is based on 'main'
# but we don't need its default gateway
table WORK nodefault
	default via work1 weight 100
	default via work2 weight 50


# -----------------------------------------------------------------------------
# define rules for selecting tables

policy

# define a mark for each gateway table.
# this makes packets originated from them to be routed back to them
	connmark 0x1 table dsl1
	connmark 0x2 table dsl2
	connmark 0x3 table dsl3
	connmark 0x11 table work1
	connmark 0x12 table work2

# You will have to add these connmark rules at the top of your firehol.conf:
# connmark 0x1 interface ppp11
# connmark 0x2 interface eth3
# connmark 0x3 interface eth4
# connmark 0x11 interface ppp14
# connmark 0x12 interface tun0

# Now you can add policy routing rules.
# TEMPLATE:
#        rules [not] [from|src IPs] [to|dst IPs] [mark X] [tos X] table TABLE_NAME
#
# example:

	# clients at 192.168.1.0 use only dsl1
	rules src 192.168.1.0/24 table dsl1

	# web server at 1.2.3.4 is routed only via dsl2
	rules dst 1.2.3.4 table dsl2

# You can use LinkBalancer to find all the IP address space of your upstream
# providers:
# Run:
#
#  ${PROGRAM_FILE} asips ONE_IP_OF_YOUR_PROVIDER
#
# LinkBalancer will query RIPE to find all the IPs of your provider.
# So you can add:

	rules dst IPS_OF_PROVIDER_1 table dsl1
	rules dst IPS_OF_PROVIDER_2 table dsl2
	rules dst IPS_OF_PROVIDER_3 table dsl3

# You can also have all the IPs in separate files:
# Run:
#
#  ${PROGRAM_FILE} asips ONE_IP_OF_YOUR_PROVIDER_1 >$SYSCONFDIR/firehol/PROVIDER1_IPS
#
# Then:
	rules dst loadfile PROVIDER1_IPS table dsl1


# Last, you may want to route local traffic to the proper table.
# This is not required through.
# It will only help if you run daemons that bind to specific IPs
# and you want them to be routed based on these IPs.

	rules src gw-src-ips dsl1 table dsl1
	rules src gw-src-ips dsl2 table dsl2
	rules src gw-src-ips dsl3 table dsl3
	rules src gw-src-ips work1 table work1
	rules src gw-src-ips work2 table work2


EOFCONFIG

echo >&2 "Saved ${LB_CONFIG}.example for your convinience..."

}

# -----------------------------------------------------------------------------
# options

emit_version

while [ ! -z "$1" ]
do
	case "$1" in
		-h|--help)
			help
			exit 0
			;;

		-t|--test)
			DRY_RUN=1
			;;

		-f|--fast)
			FORCE_ALWAYSON=1
			;;

		-d|--debug)
			DEBUG_ALL_DATA=1
			;;

		asips)
			shift
			asips "${@}"
			LB_RESULT_CODE=$?
			exit ${LB_RESULT_CODE}
			;;

		*)
			echo >&2 "Unknown option '$1'"
			exit 1
			;;
	esac
	shift
done

syslog "Started"

if [ ! -f "${LB_CONFIG}" ]
then
	echo >&2 "Cannot find config file '${LB_CONFIG}'"
	exit 1
fi

printf >&2 "\n\n###############################################################################\n"
printf >&2 "PROCESSING CONFIGURATION\n"

# process the script
enable -n trap			# Disable the trap buildin shell command.
{ source "${LB_CONFIG}"; }
ret=$?
enable trap
if [ $ret -ne 0 ]
then
	error "Preprocessing of '${LB_CONFIG}' failed with code $ret. No changes made to your system."
	exit 1
fi

# apply the changes
printf >&2 "\n\n###############################################################################\n"
printf >&2 "APPLYING CHANGES\n"

test -f "${LB_DIR}/tables.4" && finalize_tables 4
test -f "${LB_DIR}/tables.6" && finalize_tables 6
test ${LB_DO_RULES_IPV4} -eq 1 && finalize_rules 4
test ${LB_DO_RULES_IPV6} -eq 1 && finalize_rules 6
LB_RESULT_CODE=0

# all done!
echo >&2
test ! -z "${!LB_ALTERED[*]}" && warning "Altered: ${!LB_ALTERED[@]}"

# No need to cleanup
# The trap will cleanup the temporary directory
