openvpn: Show port forwarding info

Signed-off-by: James Valleroy <jvalleroy@mailbox.org>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/modules/openvpn/templates/openvpn.html

@@ -118,6 +118,24 @@
 
     {% include "diagnostics_button.html" with module="openvpn" enabled=status.enabled %}
 
+    {% if port_forwarding_info %}
+      <h3>{% trans "Port Forwarding" %}</h3>
+
+      <p>
+        {% blocktrans trimmed %}
+          If your FreedomBox is behind a router, you will need to set up port
+          forwarding on your router. You should forward the following ports for
+          OpenVPN:
+        {% endblocktrans %}
+      </p>
+
+      <ul>
+        {% for port in port_forwarding_info %}
+          <li>{{ port.0 }} {{ port.1 }}</li>
+        {% endfor %}
+      </ul>
+    {% endif %}
+
     <h3>{% trans "Configuration" %}</h3>
 
     <form class="form form-configuration" method="post">