#!/bin/sh
# 
# ifrt         implements simple route-table into /etc/network/interfaces
#
# Version:     $Id: ifrt,v 1.107 2012/10/26 01:53:58 $
#
##  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, write to the Free Software
##  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
##
## Copyright 2012  Helios le Guillou de Creisquer <creis@balios.net>


[ -z "$IF_RT" ] && exit 0
[ -z "$IF_RT_GW" ] && exit 0

if [ "$MODE" = "start" ]; then
	# Creates the VRF if not present in /etc/iproute2/rt_tables
	grep -qEi "$IF_RT[ 	]*$IFACE" /etc/iproute2/rt_tables \
		|| /bin/echo -e "$IF_RT\t$IFACE" >> /etc/iproute2/rt_tables
	
	# Add the default route (rt-gw) in the VRF if not present
	ip route show table $IF_RT | grep -qEi "default via $IF_RT_GW" \
		|| ip route add default via $IF_RT_GW table $IF_RT
	
	# Creates a rule to ensure that packets marked with rt-fwmark are routed accordingly
	for fwmark in $IF_RT_FWMARK; do
		ip rule show | grep -qEi "from all fwmark $fwmark lookup $IFACE" \
			|| ip rule add from all fwmark $fwmark lookup $IFACE

		# Ensure that the mangle table correctly marks new connections incoming on the interface
		if ! iptables -L -nv -t mangle | grep -q 'CONNMARK.*'$IFACE'.*'$IF_ADDRESS'.*state NEW CONNMARK set.*'$IF_RT_FWMARK; then
			iptables -t mangle -A PREROUTING -i $IFACE -d $IF_ADDRESS -m state --state NEW -j CONNMARK --set-mark $IF_RT_FWMARK
		fi

		# Ensure that the mangle table correctly restore the mark for packets from existing connections
		if ! iptables -L -nv -t mangle | grep -q 'CONNMARK.*eth+.*CONNMARK restore'; then
			iptables -t mangle -A PREROUTING -i eth+ -j CONNMARK --restore-mark
		fi
	done

	# for each address listed as rt-oa on the interface, add a rule to say that this source IP
	# should be routed on the correct VRF.
	for addr in $IF_ADDRESS $IF_RT_OA; do
		ip rule show | grep -qEi "from $addr lookup $IFACE" \
			|| ip rule add from $addr table $IF_RT
	done

	# Imports global route table into VRF table
	if [ ! -z "$IF_RT_IMPORTGLOBAL" ]; then
		ip route show \
		| sed -e 's/$/ table '$IF_RT'/g' -e 's/^/ip route add /g' \
		| sh 2>&1 || true
	fi

	
elif [ "$MODE" = "stop" ]; then

	for addr in $IF_ADDRESS $IF_RT_OA; do
		ip rule show | grep -qEi "from $addr lookup $IFACE" \
			&& ip rule del from $addr lookup $IFACE
	done

	for fwmark in $IF_RT_FWMARK; do
		ip rule show | grep -qEi "from all fwmark $fwmark lookup $IFACE" \
			|| ip rule del from all fwmark $fwmark lookup $IFACE

		if iptables -L -nv -t mangle | grep -q 'CONNMARK.*'$IFACE'.*'$IF_ADDRESS'.*state NEW CONNMARK set.*'$IF_RT_FWMARK; then
			iptables -t mangle -D PREROUTING -i $IFACE -d $IF_ADDRESS -m state --state NEW -j CONNMARK --set-mark $IF_RT_FWMARK
		fi


	done


	ip route show table $IF_RT | grep -qEi "default via $IF_RT_GW" \
		&& ip route del default via $IF_RT_GW table $IF_RT

	grep -v "$IF_RT[ 	]*$IFACE" /etc/iproute2/rt_tables \
		> /etc/iproute2/rt_tables.tmp
	mv  /etc/iproute2/rt_tables.tmp /etc/iproute2/rt_tables
fi