#! /bin/sh
set -eo pipefail

wan_iface="eth8"            # "eth9" for UDM Pro WAN2
vlans="br0"                 # "br0 br100 br101..."
domain="example.invalid"    # DNS domain
dns6="[2001:4860:4860::8888],[2001:4860:4860::8844]" # Google

CONTAINER=att-ipv6
confdir=/mnt/data/att-ipv6

# main
mkdir -p "${confdir}/dhcpcd"

test -f "${confdir}/dhcpcd.conf" || {
  : > "${confdir}/dhcpcd.conf.tmp"
  cat >> "${confdir}/dhcpcd.conf.tmp" <<EOF
allowinterfaces ${wan_iface}
nodev
noup
ipv6only
nooption domain_name_servers
nooption domain_name
duid
persistent
option rapid_commit
option interface_mtu
require dhcp_server_identifier
slaac private
noipv6rs

interface ${wan_iface}
  ipv6rs
  ia_na 0
EOF

  ix=0
  for vv in $vlans; do
    echo "  ia_pd ${ix} ${vv}/0"
    ix=$((ix+1))
  done >> "${confdir}/dhcpcd.conf.tmp"
  mv "${confdir}/dhcpcd.conf.tmp" "${confdir}/dhcpcd.conf"
}

test -f "${confdir}/att-ipv6-dnsmasq.conf" || {
  : > "${confdir}/att-ipv6-dnsmasq.conf.tmp"
  cat >> "${confdir}/att-ipv6-dnsmasq.conf.tmp" <<EOF
#
# via att-ipv6
#
enable-ra
no-dhcp-interface=lo
no-ping
EOF

  for vv in $vlans; do
    cat <<EOF

interface=${vv}
dhcp-range=set:att-ipv6-${vv},::2,::7d1,constructor:${vv},slaac,ra-names,64,86400
dhcp-option=tag:att-ipv6-${vv},option6:dns-server,${dns6}
domain=${domain}|${vv}
ra-param=${vv},high,0
EOF
  done >> "${confdir}/att-ipv6-dnsmasq.conf.tmp"
mv "${confdir}/att-ipv6-dnsmasq.conf.tmp" "${confdir}/att-ipv6-dnsmasq.conf"
}


if podman container exists "$CONTAINER"; then
  podman start "$CONTAINER"
else
  podman run -d --restart=always --name "$CONTAINER" -v "${confdir}/dhcpcd.conf:/etc/dhcpcd.conf" -v "${confdir}/dhcpcd:/var/lib/dhcpcd" --net=host --privileged ghcr.io/michaelw/dhcpcd
fi


# Fix DHCP, assumes DHCPv6 is turned off in UI
cp "${confdir}/att-ipv6-dnsmasq.conf" /run/dnsmasq.conf.d/
start-stop-daemon -K -q -x /usr/sbin/dnsmasq