#!/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/>.       #
#                                                                             #
###############################################################################

shopt -s nullglob

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
	remote 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 mode interface_mode interface_address interface_mtu rest
)

log() {
	logger -t ipsec "$@"
}

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

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

	local interfaces=()

	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

		# Determine the interface name
		case "${interface_mode}" in
			gre|vti)
				local intf="${interface_mode}${id}"
				;;
			*)
				continue
				;;
		esac

		# Add the interface to the list of all interfaces
		interfaces+=( "${intf}" )

		local args=(
			"local" "${VPN_IP}"
			"remote" "${righthost}"
			"ttl" "255"
		)

		# Add key for VTI
		if [ "${interface_mode}" = "vti" ]; then
			args+=( key "${id}" )
		fi

		# Update the settings when the interface already exists
		if [ -d "/sys/class/net/${intf}" ]; then
			ip link change dev "${intf}" \
				type "${interface_mode}" "${args[@]}" &>/dev/null

		# Create a new interface and bring it up
		else
			log "Creating interface ${intf}"
			ip link add name "${intf}" type "${interface_mode}" "${args[@]}"
		fi

		# Add an IP address
		ip addr flush dev "${intf}"
		ip addr add "${interface_address}" dev "${intf}"

		# Set MTU
		ip link set dev "${intf}" mtu "${interface_mtu}"

		# Bring up the interface
		ip link set dev "${intf}" up
	done < "${VPN_CONFIG}"

	# Delete all other interfaces
	local intf
	for intf in /sys/class/net/gre* /sys/class/net/vti*; do
		intf="$(basename "${intf}")"

		# Ignore a couple of interfaces that cannot be deleted
		case "${intf}" in
			gre0|gretap0)
				continue
				;;
		esac

		# Check if interface is on the list
		local i found="false"
		for i in ${interfaces[@]}; do
			if [ "${intf}" = "${i}" ]; then
				found="true"
				break
			fi
		done

		# Nothing to do if interface was found
		${found} && continue

		# Delete the interface
		log "Deleting interface ${intf}"
		ip link del "${intf}" &>/dev/null
	done
}

main || exit $?