vpnclient_ynh/conf/optional-scripts/route-up.d/50-vpnclient-set-ipv6-send-over-tun

#!/bin/bash

# cf https://openvpn.net/community-resources/reference-manual-for-openvpn-2-4/#environmental-variables
# to have a list of variables provided by OpenVPN, i.e:
# - dev
# - net_gateway_ipv6
# - ifconfig_ipv6_local
gateway_interface=${dev}
ip6_gw=${net_gateway_ipv6}

if [[ -n "${net_gateway_ipv6}" ]]; then
  echo "[INFO] Native IPv6 detected"
  echo "[INFO] Autodetected native IPv6 gateway: ${ip6_gw}"

  ip6_addr=$(yunohost app setting "vpnclient" "ip6_addr")
  if [[ -z "${ip6_addr}" ]] || [[ "${ip6_addr}" == none ]]; then
    if [[ -z ${ifconfig_ipv6_local} ]]; then
      echo "[FAIL] Cannot find IPv6 address"
      exit 1
    fi
    ip6_addr="${ifconfig_ipv6_local}"
  fi

  echo "[INFO] Found IPv6 address: ${ip6_addr}"

  echo "1 send_over_tun" > /etc/iproute2/rt_tables.d/vpnclient_ynh.conf
  ip -6 route flush table send_over_tun || true
  ip -6 route add default via "${ip6_gw}" dev "${gateway_interface}" table send_over_tun proto static
  ip -6 rule flush lookup send_over_tun
  ip -6 rule add from "${ip6_addr}/64" pref 1 table send_over_tun
fi