ffdo-ansible-l2tp/roles/gateways_gre_upstream/templates/gre_peering.j2

{% if ffrl_tun is defined %}
{% for tun in ffrl_tun %}

auto tun-ffrl-{{tun.name}}
iface tun-ffrl-{{tun.name}} inet static
        address {{tun.v4_remote | ipaddr( tun.v4_remote.split('.')[3] | int + 1) | ipaddr('address') }}
        netmask {{tun.v4_remote | ipaddr('netmask')}}
        pre-up ip tunnel add $IFACE mode gre local {{ansible_default_ipv4.address}} remote {{tun.gre_target | ipaddr('address') }} ttl 255
        post-up ip link set $IFACE mtu 1400
        post-down ip tunnel del $IFACE
        post-up ip rule add iif $IFACE lookup ffnet
        pre-down ip rule del iif $IFACE lookup ffnet ||:
iface tun-ffrl-{{tun.name}} inet6 static
        address {{tun.v6_remote | ipaddr('2') | ipaddr('address') }}
        netmask {{tun.v6_remote | ipaddr('prefix')}}
        post-up ip -6 rule add iif $IFACE lookup ffnet
        pre-down ip -6 rule del iif $IFACE lookup ffnet ||:
{% endfor %}
{% endif %}