#!/bin/bash
###############################################################################
#                                                                             #
# IPFire.org - A linux based firewall                                         #
# Copyright (C) 2012  IPFire Network Development Team                         #
#                                                                             #
# 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 3 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/>.       #
#                                                                             #
###############################################################################
#
# Functions for static routing.
#

function route_init() {
	# Apply configured static routes.
	route_apply
}

init_register route_init

function route_add() {
	local ${NETWORK_CONFIG_ROUTES_PARAMS}

	while [ $# -gt 0 ]; do
		case "${1}" in
			--gateway=*)
				gateway=$(cli_get_val ${1})
				;;
			--unreachable)
				unreachable="true"
				;;
			--prohibit)
				prohibit="true"
				;;
			--blackhole)
				blackhole="true"
				;;
			--mtu=*)
				mtu=$(cli_get_val ${1})
				;;
			*)
				network=${1}
				;;
		esac
		shift
	done

	assert isset network

	if ! ip_is_valid ${network}; then
		error "The given network is invalid: ${network}"
		return ${EXIT_ERROR}
	fi

	if route_find_duplicate ${network}; then
		error "A route to ${network} does already exist."
		return ${EXIT_ERROR}
	fi

	# Check if gateway and unreachable are both enabled.
	if isset gateway; then
		if enabled unreachable; then
			error "You cannot use both, --gateway=${gateway} and --unreachable at the same time."
			return ${EXIT_ERROR}
		fi

		if enabled prohibit; then
			error "You cannot use both, --gateway=${gateway} and --prohibit at the same time."
			return ${EXIT_ERROR}
		fi

		if enabled blackhole; then
			error "You cannot use both, --gateway=${gateway} and --blackhole at the same time."
			return ${EXIT_ERROR}
		fi

		# Check if network and gateway IP protocol version match.
		if ! ip_is_valid ${gateway}; then
			error "--gateway= is not a valid IP address."
			return ${EXIT_ERROR}
		fi

		local network_proto=$(ip_detect_protocol ${network})
		local gateway_proto=$(ip_detect_protocol ${gateway})

		if [ "${network_proto}" != "${gateway_proto}" ]; then
			error "The IP protocol version of the given network and gateway did not match."
			return ${EXIT_ERROR}
		fi

	else
		local counter=$(list_count true ${unreachable} ${prohibit} ${blackhole})
		if [ ${counter} -gt 1 ]; then
			error "You can only use one of --unreachable, --prohibit or --blackhole."
			return ${EXIT_ERROR}
		fi
	fi

	if isset mtu && ! isinteger mtu; then
		error "MTU must be an integer number: ${mtu}"
		return ${EXIT_ERROR}
	fi

	local line
	list_append line "network=\"${network}\""

	# Add gateway to configuration entry when it is set.
	if isset gateway; then
		list_append line "gateway=\"${gateway}\""
	fi

	# Add unreachable to configuration entry when it is set.
	local arg
	for arg in unreachable prohibit blackhole; do
		if enabled ${arg}; then
			list_append line "${arg}=\"true\""
			break
		fi
	done

	# Add MTU (if set).
	if isset mtu; then
		list_append line "mtu=\"${mtu}\""
	fi

	# Write line to file.
	print "${line}" >> ${NETWORK_CONFIG_ROUTES}

	log INFO "New route to network '${network}' has been added."
	return ${EXIT_OK}
}

function route_remove() {
	local _network=${1}
	assert isset _network

	local found="false"

	local ${NETWORK_CONFIG_ROUTES_PARAMS}
	local line
	while read line; do
		route_parse_line ${line}
		[ $? -eq ${EXIT_OK} ] || continue

		# Skip the rule, we want to delete.
		if [ "${network}" = "${_network}" ]; then
			found="true"
			continue
		fi

		print "${line}"
	done < ${NETWORK_CONFIG_ROUTES} > ${NETWORK_CONFIG_ROUTES}.tmp
	mv ${NETWORK_CONFIG_ROUTES}{.tmp,}

	if enabled found; then
		log INFO "Route to network '${_network}' has been removed."
	else
		error "No route to network '${_network}' was found."
		return ${EXIT_ERROR}
	fi

	return ${EXIT_OK}
}

function route_list() {
	local protocol

	while [ $# -gt 0 ]; do
		case "${1}" in
			--protocol=*)
				protocol=$(cli_get_val ${1})
				;;
			*)
				warning "Unrecognized argument: ${1}"
				;;
		esac
		shift
	done

	if [ ! -r "${NETWORK_CONFIG_ROUTES}" ]; then
		print "No static routes defined."
		return ${EXIT_OK}
	fi

	local format="%-40s %-20s %-4s"
	print "${format}" "NETWORK/HOST" "GATEWAY" "MTU"

	local ${NETWORK_CONFIG_ROUTES_PARAMS}
	local line
	while read line; do
		route_parse_line ${line}
		[ $? -eq ${EXIT_OK} ] || continue

		local arg
		for arg in unreachable prohibit blackhole; do
			if enabled ${arg}; then
				gateway="<${arg}>"
				break
			fi
		done

		# Filter all entries with a wrong protocol.
		if isset protocol; then
			local proto=$(ip_detect_protocol ${network})
			[ "${protocol}" = "${proto}" ] || continue
		fi

		# Print something when no MTU was set.
		if ! isset mtu; then
			mtu="-"
		fi

		print "${format}" "${network}" "${gateway}" "${mtu}"
	done < ${NETWORK_CONFIG_ROUTES}
}

function route_find_duplicate() {
	local _network=${1}

	[ -r "${NETWORK_CONFIG_ROUTES}" ] || return ${EXIT_FALSE}

	local ${NETWORK_CONFIG_ROUTES_PARAMS}
	local line
	while read line; do
		route_parse_line ${line}
		[ $? -eq ${EXIT_OK} ] || continue

		# Check if the network is already in use.
		[ "${network}" = "${_network}" ] && return ${EXIT_TRUE}
	done < ${NETWORK_CONFIG_ROUTES}

	return ${EXIT_FALSE}
}

function route_parse_line() {
	local arg

	# Reset all possible settings.
	for arg in ${NETWORK_CONFIG_ROUTES_PARAMS}; do
		printf -v ${arg} "%s" ""
	done

	while read arg; do
		case "${arg}" in
			network=*)
				network=$(cli_get_val ${arg})
				;;
			gateway=*)
				gateway=$(cli_get_val ${arg})
				;;
			unreachable=*)
				unreachable=$(cli_get_val ${arg})
				;;
			prohibit=*)
				prohibit=$(cli_get_val ${arg})
				;;
			blackhole=*)
				blackhole=$(cli_get_val ${arg})
				;;
			mtu=*)
				mtu=$(cli_get_val ${arg})
				;;
		esac
	done <<< "$(args $@)"

	### Check if all values are correctly set.

	# network must be set.
	isset network || return ${EXIT_ERROR}

	# network must be a valid.
	ip_is_network ${network} || return ${EXIT_ERROR}

	# Check gateway settings.
	if isset gateway; then
		# When gateway is set, unreachable cannot be set.
		isset unreachable && return ${EXIT_ERROR}

		# Must be a valid IP address.
		ip_is_valid ${gateway} || return ${EXIT_ERROR}
	else
		# Check if exactly one of unreachable, prohibit or blackhole is set.
		local counter=$(list_count true ${unreachable} ${prohibit} ${blackhole})
		[ ${counter} -eq 1 ] || return ${EXIT_ERROR}
	fi

	# mtu must be an integer number.
	if isset mtu; then
		isinteger mtu || return ${EXIT_ERROR}
	fi

	return ${EXIT_OK}
}

function route_apply() {
	local table="static"
	local type

	log INFO "Applying static routes..."

	# Flush the routing table.
	route_table_flush ${table}

	local ${NETWORK_CONFIG_ROUTES_PARAMS}
	local line
	while read line; do
		route_parse_line ${line}
		[ $? -eq ${EXIT_OK} ] || continue

		type="unicast"
		local arg
		for arg in unreachable prohibit blackhole; do
			if enabled ${arg}; then
				type="${arg}"
				break
			fi
		done

		# Add the route.
		route_entry_add ${network} --table="static" --proto="static" \
			--type="${type}" --gateway="${gateway}" --mtu="${mtu}"
		local ret=$?

		if [ ${ret} -ne ${EXIT_OK} ]; then
			log WARNING "Could not set route '${network}'."
		fi
	done < ${NETWORK_CONFIG_ROUTES}

	# Create a lookup rule for the static routing table.
	route_rule_add --lookup="static" --priority=1000
}

function route_entry_add() {
	local gateway
	local network
	local proto
	local table
	local type="unicast"
	local mtu

	local command

	while [ $# -gt 0 ]; do
		case "${1}" in
			--gateway=*)
				gateway=$(cli_get_val ${1})
				;;
			--table=*)
				table=$(cli_get_val ${1})
				;;
			--type=*)
				type=$(cli_get_val ${1})
				;;
			--proto=*)
				proto=$(cli_get_val ${1})
				;;
			--mtu=*)
				mtu=$(cli_get_val ${1})
				;;
			*)
				if isset network; then
					warning "Unrecognized argument: ${1}"
				else
					network=${1}
				fi
				;;
		esac
		shift
	done

	# Validate input.
	assert isoneof type unicast broadcast unreachable prohibit blackhole
	assert ip_is_network ${network}
	if isset mtu; then
		assert isinteger mtu
	fi

	# Detect the protocol of the given network.
	local protocol=$(ip_detect_protocol ${network})
	case "${protocol}" in
		ipv6)
			command="ip -6 route add"
			;;
		ipv4)
			command="ip route add"
			;;
	esac
	assert isset command

	# Add type.
	list_append command "${type}"

	# Add network/prefix.
	list_append command "${network}"

	if [ "${type}" = "unicast" ]; then
		assert isset gateway
		assert ip_is_valid ${gateway}

		list_append command "via ${gateway}"
	fi

	# Add table (if any).
	if isset table; then
		# Create routing table, if it does not exist, yet.
		route_table_create ${table}

		list_append command "table ${table}"
	fi

	# Add proto.
	if isset proto; then
		list_append command "proto ${proto}"
	fi

	# Add MTU.
	if isset mtu; then
		list_append command "mtu ${mtu}"
	fi

	cmd_quiet "${command}"
}

function route_table_create() {
	local table=${1}
	assert isset table

	if route_table_exists ${table}; then
		return ${EXIT_OK}
	fi

	# Get the next free id.
	local id=$(_route_table_next_id)
	assert isset id

	# Write everything to file.
	print "%d\t%s" "${id}" "${table}" >> /etc/iproute2/rt_tables

	log DEBUG "Created routing table '${table}'."

	return ${EXIT_OK}
}

function _route_table_next_id() {
	# The Linux kernel is able to manage 255 routing tables (1-255).
	# This function returns the next free id, starting from 255.
	local next_id

	for next_id in {255..1}; do
		if ! route_table_exists --id="${next_id}"; then
			print "${next_id}"
			return ${EXIT_OK}
		fi
	done

	return ${EXIT_FALSE}
}

function route_table_flush() {
	local protocol
	local table

	while [ $# -gt 0 ]; do
		case "${1}" in
			--protocol=*)
				protocol=$(cli_get_val ${1})
				;;
			*)
				table="${1}"
				;;
		esac
		shift
	done

	# If the table does not exists, there is nothing to
	# flush.
	route_table_exists ${table} || return ${EXIT_OK}

	local command
	local proto
	for proto in ${IP_SUPPORTED_PROTOCOLS}; do
		# Skip unwanted protocols.
		if isset protocol; then
			[ "${protocol}" = "${proto}" ] || continue
		fi

		command=""
		case "${proto}" in
			ipv6)
				command="ip -6 route flush"
				;;
			ipv4)
				command="ip route flush"
				;;
		esac
		assert isset command

		list_append command "table ${table}"

		# Execute command.
		cmd "${command}"
	done

	return ${EXIT_OK}
}

function route_table_exists() {
	local _id _table

	while [ $# -gt 0 ]; do
		case "${1}" in
			--id=*)
				_id=$(cli_get_val ${1})
				;;
			*)
				_table=${1}
				break
				;;
		esac
		shift
	done

	local id table
	while read -r id table; do
		# Skip all comments.
		[ "${id:0:1}" = "#" ] && continue

		if [ "${_table}" = "${table}" ] || [ "${_id}" = "${id}" ]; then
			# Found a match.
			return ${EXIT_TRUE}
		fi
	done < /etc/iproute2/rt_tables

	return ${EXIT_FALSE}
}

function route_rule_add() {
	local priority
	local protocols=${IP_SUPPORTED_PROTOCOLS}
	local lookup

	while [ $# -gt 0 ]; do
		case "${1}" in
			--lookup=*)
				lookup=$(cli_get_val ${1})
				;;
			--priority=*)
				priority=$(cli_get_val ${1})
				;;
			--protocol=*)
				protocols=$(cli_get_val ${1})

				assert isoneof protocols ${IP_SUPPORTED_PROTOCOLS}
				;;
			*)
				warning "Unhandled argument: ${1}"
				;;
		esac
		shift
	done

	local command options

	if isset lookup; then
		route_table_create ${lookup}

		list_append options "lookup ${lookup}"
	fi

	if isset priority; then
		assert isinteger priority

		list_append options "prio ${priority}"
	fi

	local proto
	for proto in ${protocols}; do
		command=
		case "${proto}" in
			ipv6)
				command="ip -6 rule add  ${options}"
				;;
			ipv4)
				command="ip rule add ${options}"
				;;
		esac
		assert isset command

		# Skip, if the rule does already exist.
		route_rule_exists \
			--protocol=${proto} \
			--lookup=${lookup} \
			--priority=${priority} \
			&& continue

		cmd "${command}"
	done
}

function route_rule_exists() {
	local from
	local lookup
	local proto
	local prio

	while [ $# -gt 0 ]; do
		case "${1}" in
			--from=*)
				from=$(cli_get_val ${1})
				;;
			--lookup=*)
				lookup=$(cli_get_val ${1})
				;;
			--priority=*)
				prio=$(cli_get_val ${1})
				;;
			--protocol=*)
				proto=$(cli_get_val ${1})
				;;
			*)
				warning "Unrecognized argument: ${1}"
				;;
		esac
		shift
	done

	local command
	case "${proto}" in
		ipv6)
			command="ip -6 rule show"
			;;
		ipv4)
			command="ip rule show"
			;;
	esac
	assert isset command

	local _lookup _from _prio
	local line
	while read -r line; do
		_route_rule_exists_parse ${line}

		if isset from; then
			[ "${from}" = "${_from}" ] || continue
		fi

		if isset prio; then
			[ "${prio}" = "${_prio}" ] || continue
		fi

		if isset lookup; then
			[ "${lookup}" = "${_lookup}" ] || continue
		fi

		return ${EXIT_TRUE}
	done <<< "$(${command})"

	return ${EXIT_FALSE}
}

function _route_rule_exists_parse() {
	# Reset all variables.
	_lookup=
	_from=
	_prio=

	while [ $# -gt 0 ]; do
		case "${1}" in
			lookup)
				_lookup=${2}
				shift 2
				;;
			from)
				_from=${2}
				shift 2
				;;
			*:)
				_prio=${1//:/}
				shift
				;;
			*)
				# Skip unknown arguments.
				shift
				;;
		esac
	done
}