Enable some recommended Coturn options in an effort to lower DDoS amplification factor

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2592

roles/custom/matrix-coturn/defaults/main.yml

@@ -112,11 +112,25 @@ matrix_coturn_user_quota: null
 matrix_coturn_total_quota: null
 
 # Controls whether `no-tcp-relay` is added to the configuration
+# Learn more here: https://github.com/coturn/coturn/blob/242eb78227f66442ba1573c00ec4552faae23eed/examples/etc/turnserver.conf#L419-L422
 matrix_coturn_no_tcp_relay_enabled: true
 
 # Controls whether `no-multicast-peers` is added to the configuration
+# Learn more here: https://github.com/coturn/coturn/blob/242eb78227f66442ba1573c00ec4552faae23eed/examples/etc/turnserver.conf#L629-L632
 matrix_coturn_no_multicast_peers_enabled: true
 
+# Controls whether `no-rfc5780` is added to the configuration
+# Learn more here: https://github.com/coturn/coturn/blob/242eb78227f66442ba1573c00ec4552faae23eed/examples/etc/turnserver.conf#L770-L781
+matrix_coturn_no_rfc5780_enabled: true
+
+# Controls whether `no-stun-backward-compatibility` is added to the configuration
+# Learn more here: https://github.com/coturn/coturn/blob/242eb78227f66442ba1573c00ec4552faae23eed/examples/etc/turnserver.conf#L783-L789
+matrix_coturn_no_stun_backward_compatibility_enabled: true
+
+# Controls whether `response-origin-only-with-rfc5780` is added to the configuration
+# Learn more here: https://github.com/coturn/coturn/blob/242eb78227f66442ba1573c00ec4552faae23eed/examples/etc/turnserver.conf#L791-L796
+matrix_coturn_response_origin_only_with_rfc5780_enabled: true
+
 # Additional configuration to be passed to turnserver.conf
 # Example:
 # matrix_coturn_additional_configuration: |

roles/custom/matrix-coturn/templates/turnserver.conf.j2

@@ -35,6 +35,18 @@ prod
 no-tcp-relay
 {% endif %}
 
+{% if matrix_coturn_no_rfc5780_enabled %}
+no-rfc5780
+{% endif %}
+
+{% if matrix_coturn_no_stun_backward_compatibility_enabled %}
+no-stun-backward-compatibility
+{% endif %}
+
+{% if matrix_coturn_response_origin_only_with_rfc5780_enabled %}
+response-origin-only-with-rfc5780
+{% endif %}
+
 {% if matrix_coturn_user_quota != None %}
 user-quota={{ matrix_coturn_user_quota }}
 {% endif %}