#!/bin/sh

color_default=$(tput setaf 7);
color_config=$(tput setaf 3);
color_error=$(tput setaf 1);
color_log=$(tput setaf 8);
echo "$(figlet jool clat)${color_log}"

ip netns pids jool
if [ $? -eq 0 ]; then
	echo "${color_error}> already running - teardown ${color_log}"
	ip netns del jool
	exit 0
fi

#
# TODO:
# - get $nat64_subnet by ipv4only.arpa request
# - skip if ipv4 default route exists
# - improve $nat64_gw generation for ipv6 address in namespace
# - improve subnet sizes - hardcoded /64 and /96

nat64_subnet="64:ff9b::"
echo "${color_default}detect nat64: ${color_config}$nat64_subnet${color_log}"

ifname_ex="$(ip r g ${nat64_subnet}0 | grep -Po 'dev \K[0-9a-z]+')"
echo "${color_default}over interface: ${color_config}$ifname_ex${color_log}"

#
# setup interfaces and namespace
#

echo "${color_default}> setup interfaces and namespace${color_log}"
ip netns add jool
ip link add name clat type veth peer name to_world
ip link set up dev clat
ip link set up dev to_world netns jool

clat_ll=$(ip -6 address show scope link dev clat | grep -Po 'inet6 \K[0-9a-f:]+')
internal_ll=$(ip netns exec jool ip -6 address show scope link dev to_world | grep -Po 'inet6 \K[0-9a-f:]+')


#
# setup network in namespace
#

echo "${color_default}> setup network in namespace${color_log}"

nat64_gw="$(ip r g ${nat64_subnet}0  | grep -Po 'src \K[0-9a-f]+:[0-9a-f]+:[0-9a-f]+:[0-9a-f]+:')$(echo $internal_ll | grep -Po 'fe80::\K[0-9a-f:]+')"

echo "${color_default}generate internal ipv6 address: ${color_config}$nat64_gw${color_log}"
ip netns exec jool ip -6 address add $nat64_gw/64 dev to_world
ip netns exec jool ip -6 route add default via $clat_ll dev to_world
ip netns exec jool ip -4 address add 192.0.0.1/29 dev to_world


#
# setup jool in namespace
#

echo "${color_default}> setup jool in namespace${color_log}"
ip netns exec jool modprobe jool_siit
if [ $? -ne 0 ]; then
	echo "${color_error}module jool_siit not found${color_log}"
	ip netns del jool
	exit 1
fi
ip netns exec jool jool_siit instance add --netfilter --pool6 $nat64_subnet/96
ip netns exec jool jool_siit eamt add 192.0.0.2 $nat64_gw


#
# routing ipv6 namespace
#

echo "${color_default}> routing ipv6 to namespace${color_log}"
echo 1 > /proc/sys/net/ipv6/conf/$ifname_ex/proxy_ndp
echo 1 | tee /proc/sys/net/ipv6/conf/*/forwarding
ip -6 neigh add proxy $internal_ll dev $ifname_ex
ip -6 route add $nat64_gw/96 via $internal_ll dev clat


#
# routing ipv4 to namespace
#

echo "${color_default}> routing ipv4 to namespace${color_log}"

ip -4 address add 192.0.0.2/29 dev clat
ip -4 route add default via 192.0.0.1 dev clat