#!/bin/sh /etc/rc.common

START=90
CRON_FILE=/etc/crontabs/root

interface() {
	nic=$(ifconfig -a | grep -o '^[^ ]*')
	dhcpv6_interface=$(uci -q show network | grep -E "dhcpv6|ip6addr" | grep -o 'network\.\([^\.]*\)' | sed 's/network.//')
	IFS=$'\n'
	for interface_name in $dhcpv6_interface
	do
		device=$(uci -q show network.$interface_name.device | grep -o "'.*'" | awk -F"'" '{print $2}')
		if [ "$(echo $device | grep -c @)" = 1 ]; then
			alias_interface=$(echo $device | sed 's/@//')
			device=$(uci -q show network.$alias_interface.device | grep -o "'.*'" | awk -F"'" '{print $2}')
			if [ -z $(uci -q show network.$alias_interface.device) ]; then
				ipaddr=$(uci -q show network.$alias_interface.ipaddr | grep -o "'.*'" | awk -F"'" '{print $2}')
				device=$(ifconfig | grep -B 1 $ipaddr 2>/dev/null | head -1 | awk '{print $1}')
			fi
		fi
		if [ $(ifconfig $device | grep -c "inet6 addr") -gt 0 ]; then
			ip6gw=$(uci -q show network.$interface_name.ip6gw | grep -o "'.*'" | awk -F"'" '{print $2}')
			[ -n "$ip6gw" ] && gateway="$ip6gw" || gateway=$(ip -6 route | grep "default from" | awk '{print $5}')
			break
		fi
	done
}

hotplug_iface() {
	[ ! -f /etc/hotplug.d/iface/90-nat6 ] && cat > /etc/hotplug.d/iface/90-nat6 << "EOF"
#!/bin/sh

dhcpv6_interface=$(uci -q show network | grep dhcpv6 | grep -o 'network\.\([^\.]*\)' | sed 's/network.//')
IFS=$'\n'
for interface_name in $dhcpv6_interface
do
	device=$(uci -q show network.$interface_name.device | grep -o "'.*'" | awk -F"'" '{print $2}')
	if [ $(ifconfig $device | grep -c "inet6 addr") -gt 0 ]; then
		interface_name=$interface_name
	fi
done

[ "$INTERFACE" = "$interface_name" ] || exit 0

if [ "$ACTION" = ifup ] || [ "$ACTION" = iflink ] || [ "$ACTION" = ifupdate ] || [ "$ACTION" = reload ]; then
	/etc/init.d/nat6 restart
fi
EOF
}

common_config() {
	if [ -z $(uci -q get network.globals.ula_prefix) ] || [ $(uci -q get network.globals.ula_prefix | grep -c "/48") != 1 ]; then
		r1=$(dd if=/dev/urandom bs=1 count=1 2>/dev/null | hexdump -e '1/1 "%02x"')
		uci -q batch <<-EOF >/dev/null
			set network.globals.ula_prefix="fd$r1:2024::/48"
			commit network
EOF
		/etc/init.d/network reload
	fi
	lan_ra=$(uci -q get dhcp.lan.ra)
	lan_dhcp6=$(uci -q get dhcp.lan.dhcpv6)
	lan_ndp=$(uci -q get dhcp.lan.ndp)
	lan_ra_default=$(uci -q get dhcp.lan.ra_default)
	lan_ra_slaac=$(uci -q get dhcp.lan.ra_slaac)
	if [ "$lan_ra" != "server" ] || [ "$lan_dhcp6" != "server" ] || [ "$lan_ndp" != "" ] || [ "$lan_ra_default" != "2" ] || [ "$lan_ra_slaac" != "0" ]; then
		uci -q batch <<-EOF >/dev/null
			set dhcp.lan.ra='server'
			set dhcp.lan.dhcpv6='server'
			del dhcp.lan.ndp
			set dhcp.lan.ra_default='2'
			set dhcp.lan.ra_slaac='0'
			del dhcp.lan.ra_flags
			add_list dhcp.lan.ra_flags='managed-config'
			commit dhcp
EOF
		/etc/init.d/odhcpd reload
	fi
}

start() {
	[ "$(uci -q get firewall.@defaults[0].nat6)" != 1 ] && return 0
	interface
	hotplug_iface
	[ -z "$device" ] && logger -p error -t network -s "nat6: DHCPv6 interface device not configured, IPv6 NAT failed." && exit 0
	[ -z "$gateway" ] && logger -p error -t network -s "nat6: DHCPv6 gateway not found, IPv6 NAT failed." && exit 0
	common_config
	ip -6 r add default via $gateway dev $device 2>/dev/null
	nft delete table ip6 nat 2>/dev/null
	nft add table ip6 nat 2>/dev/null
	nft add chain ip6 nat prerouting { type nat hook prerouting priority 0\; } 2>/dev/null
	nft add chain ip6 nat postrouting { type nat hook postrouting priority 100\; } 2>/dev/null
	nft add rule ip6 nat postrouting oif $device masquerade 2>/dev/null
	grep -q "nft list table ip6 nat" $CRON_FILE || echo "* * * * * nft list table ip6 nat 2>&1 | grep -q 'iptables-nft' && ( /etc/init.d/nat6 stop ; /etc/init.d/nat6 start )" >> $CRON_FILE
	crontab $CRON_FILE
	logger -p notice -t network -s "nat6: IPv6 NAT is ready"
}

stop() {
	interface
	nft delete table ip6 nat 2>/dev/null
	ip -6 r del default via $gateway dev $device 2>/dev/null
	rm -f /etc/hotplug.d/iface/90-nat6
	uci -q batch <<-EOF >/dev/null
		del dhcp.lan.ra_default
		commit dhcp
EOF
	if [ "$(uci -q get dhcp.lan.ra_slaac)" != "" ]; then
		uci -q batch <<-EOF >/dev/null
			del dhcp.lan.ra_slaac
			del dhcp.lan.ra_flags
			commit dhcp
EOF
	fi
	sed -i '/nft list table ip6 nat/d' $CRON_FILE 2> /dev/null
	crontab $CRON_FILE
	/etc/init.d/odhcpd reload
}

restart() {
	stop
	sleep 3
	start
}