tecff-ipv6-tunnel-helper

#!/bin/bash
# this script is used on a B.A.T.M.A.N. gateway to change the routing of IPv6 packages to use the 6in4 tunnel
# dependencies: ip6tables, iproute2

if [ -z "$1" ] || [ -z "$2" ] || [ -z "$3" ] || [ -z "$4" ] || [ -z "$5" ]; then
	echo "missing parameters! ((up|down), BRIDGEIF, TUNIF, DEFGW, SUBNETIP)"
	exit 1
fi

BRIDGEIF="$2"
TUNIF="$3"
DEFGW="$4"
SUBNETIP="$5"

if [ "$1" == "up" ]; then
	ip -6 addr add $SUBNETIP dev $BRIDGEIF
	ip -6 route add unreachable default metric 2000 table 42
	ip -6 route add $SUBNETIP dev $BRIDGEIF table 42
	ip -6 route add default via $DEFGW table 42 dev $TUNIF
	ip -6 rule add iif $BRIDGEIF table 42
	ip6tables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1240
	ip6tables -A FORWARD -i $TUNIF -o $BRIDGEIF -m comment --comment "000 Allow v6-tunnel to bridge forwarding" -j ACCEPT
	ip6tables -A FORWARD -i $BRIDGEIF -o $TUNIF -m comment --comment "000 Allow bridge to v6-tunnel forwarding" -j ACCEPT
else
	systemctl stop radvd.service
	ip6tables -D FORWARD -i $TUNIF -o $BRIDGEIF -m comment --comment "000 Allow v6-tunnel to bridge forwarding" -j ACCEPT
	ip6tables -D FORWARD -i $BRIDGEIF -o $TUNIF -m comment --comment "000 Allow bridge to v6-tunnel forwarding" -j ACCEPT
	ip6tables -D FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1240
	ip -6 rule del iif $BRIDGEIF table 42
	ip -6 route del default via $DEFGW table 42 dev $TUNIF
	ip -6 route del $SUBNETIP dev $BRIDGEIF table 42
	ip -6 route del unreachable default metric 2000 table 42
	ip -6 addr del $SUBNETIP dev $BRIDGEIF
fi