tecff-bridge-routing-setup

#!/bin/bash
if [ -z "$1" ] || [ -z "$2" ]; then
	echo "missing parameters! (SUBNET4, SUBNET6)"
	exit 1
fi

# IFACE and MODE are set as an environment variable by ifupdown
SUBNET4="$1"
SUBNET6="$2"
# for IPv4, subnet in format 10.120.x.0/yz is expected
# for IPv6, subnet only the last part is expected, e.g. "96"

if [ "$MODE" == "start" ]; then
	if [[ "$SUBNET4" =~ ^10\.120\.[0-9]+\.0/[0-9]+$ ]]; then
		ip -4 rule add iif $IFACE table 42
		if ! [[ "$(ip -4 route show default table 42 | grep unreachable)" =~ "unreachable default" ]]; then
			ip -4 route add unreachable default metric 2000 table 42
		fi
		ip -4 route add $SUBNET4 dev $IFACE table 42
	fi
	if [[ "$SUBNET6" =~ ^[0-9]+$  ]]; then
		ip -6 route add 2001:470:733f:${SUBNET6}::/64 dev $IFACE
		ip -6 rule add iif $IFACE table 42
		if ! [[ "$(ip -6 route show default table 42 | grep unreachable)" =~ "unreachable default" ]]; then
			ip -6 route add unreachable default metric 2000 table 42
		fi
		ip -6 route add 2001:470:733f:${SUBNET6}::/64 dev $IFACE table 42
		ip -6 route add fdef:ffc0:4ffa:${SUBNET6}::/64 dev $IFACE table 42
	fi
elif [ "$MODE" == "stop" ]; then
	if ! ip link show dev $IFACE >/dev/null 2>&1; then
		# exit if the interface does not exist (anymore)
		exit 0
	fi
	if [[ "$SUBNET4" =~ ^10\.120\.[0-9]+\.0/[0-9]+$ ]]; then
		ip -4 route del $SUBNET4 dev $IFACE table 42
		ip -4 route del unreachable default metric 2000 table 42
		ip -4 rule del iif $IFACE table 42
	fi
	if [[ "$SUBNET6" =~ ^[0-9]+$  ]]; then
		ip -6 route del 2001:470:733f:${SUBNET6}::/64 dev $IFACE table 42
		ip -6 route del fdef:ffc0:4ffa:${SUBNET6}::/64 dev $IFACE table 42
		ip -6 route del unreachable default metric 2000 table 42
		ip -6 rule del iif $IFACE table 42
		ip -6 route del 2001:470:733f:${SUBNET6}::/64 dev $IFACE
	fi
else
	exit 1
fi