tripleo-ansible/tripleo_ansible/roles/tripleo_nftables/templates/protocol.j2

{%- if 'proto' in rule and (rule['proto']|lower) != 'all' %}
{%-   if (rule['proto']|lower) not in ['tcp', 'udp'] %}
 meta l4proto
{%-   endif %}
 {{ rule['proto']|lower }}
{%- endif %}