#!/bin/bash
###############################################################################
#                                                                             #
# IPFire.org - A linux based firewall                                         #
# Copyright (C) 2015 IPFire 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/>.       #
#                                                                             #
###############################################################################

VPN_CONFIG="/var/ipfire/vpn/config"

block_subnet() {
	local subnet="${1}"
	local action="${2}"

	# Don't block a wildcard subnet
	if [ "${subnet}" = "0.0.0.0/0" ] || [ "${subnet}" = "0.0.0.0/0.0.0.0" ]; then
		return 0
	fi

	case "${action}" in
		reject)
			iptables -A IPSECBLOCK -d "${subnet}" -j REJECT --reject-with icmp-net-unreachable
			;;
		drop)
			iptables -A IPSECBLOCK -d "${subnet}" -j DROP
			;;
		*)
			return 1
			;;
	esac

	return 0
}

block_ipsec() {
	# Flush all exists rules
	iptables -F IPSECBLOCK

	local action

	local vars="id status name lefthost type ctype x1 x2 x3 leftsubnets"
	vars="${vars} x4 righthost rightsubnets x5 x6 x7 x8 x9 x10 x11 x12"
	vars="${vars} x13 x14 x15 x16 x17 x18 x19 x20 x21 proto x22 x23 x24"
	vars="${vars} route rest"

	# Register local variables
	local ${vars}

	while IFS="," read -r ${vars}; do
		# Check if the connection is enabled
		[ "${status}" = "on" ] || continue

		# Check if this a net-to-net connection
		[ "${type}" = "net" ] || continue

		# Split multiple subnets
		rightsubnets="${rightsubnets//\|/ }"

		case "${route}" in
			route)
				action="drop"
				;;
			*)
				action="reject"
				;;
		esac

		local rightsubnet
		for rightsubnet in ${rightsubnets}; do
			block_subnet "${rightsubnet}" "${action}"
		done
	done < "${VPN_CONFIG}"
}

block_ipsec || exit $?