#!/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"

eval $(/usr/local/bin/readhash /var/ipfire/vpn/settings)

VARS=(
	id status name lefthost type ctype x1 x2 x3 leftsubnets
	x4 righthost rightsubnets x5 x6 x7 x8 x9 x10 x11 x12
	x13 x14 x15 x16 x17 x18 x19 x20 x21 proto x22 x23 x24
	route x26 x27 x28 x29 x30 x31 x32 x33 x34 x35
	interface_mode interface_address interface_mtu rest
)

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
}

install_policy() {
	# Flush existing rules
	iptables -F IPSECINPUT
	iptables -F IPSECOUTPUT
	iptables -F IPSECBLOCK

	# We are done when IPsec is not enabled
	[ "${ENABLED}" = "on" ] || exit 0

	# IKE
	iptables -A IPSECINPUT  -p udp --dport 500 -j ACCEPT
	iptables -A IPSECOUTPUT -p udp --dport 500 -j ACCEPT

	# IKE NAT
	iptables -A IPSECINPUT  -p udp --dport 4500 -j ACCEPT
	iptables -A IPSECOUTPUT -p udp --dport 4500 -j ACCEPT

	# Register local variables
	local "${VARS[@]}"
	local action

	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}"
}

install_policy || exit $?