feat(remote support) Enhance documentation with session management

remote_support.rst

@@ -15,11 +15,97 @@ by Nethesis at ``sos.nethesis.it``.
 The firewall must be able to connect to the above host on port ``1194`` UDP. If port ``1194`` is closed,
 the system will try to fallback on port ``443`` TCP.
 
+Session management
+==================
+
 The remote support must be started and stopped by the firewall administrator.
+
+Starting a session
+------------------
+
 To start a session:
 
 - access the ``Subscription`` page and go to the ``Remote support`` section
 - click the :guilabel:`Start session` button
 - copy the ``Session ID`` and share it with the support team
+- the session will be active for 24 hours by default
+
+The system will display:
+
+- The current session status (active/inactive)
+- The session expiration time
+- The remaining time until expiration
+
+You can view this information at any time in the ``Remote support`` section of the ``Subscription`` page.
+
+Session expiration
+------------------
+
+Remote support sessions have the following expiration behavior:
+
+- **Default session**: expires after 24 hours
+- **Extended session**: expires after 7 days from the extension time
+
+The system continuously monitors session expiration:
+
+- A cron job runs every hour to check for expired sessions
+- When a session expires, it is automatically stopped
+- Session expiration events are logged to the system log
+
+
+Terminating a session
+---------------------
+
+To manually terminate an active session before it expires:
+
+- access the ``Subscription`` page and go to the ``Remote support`` section
+- click the :guilabel:`End session` button
+- the remote support connection will be immediately closed
+
+Command Line Interface
+======================
+
+The ``don`` command requires root privileges and logs all operations to the system log.
+
+Start a session::
+
+    don start
+
+This will start a new remote support session with a 24-hour expiration.
+
+Check session status::
+
+    don status
+
+This displays the current session information including:
+
+- Server ID
+- Session ID
+- Time remaining until expiration
+
+Extend an active session::
+
+    don extend
+
+.. important::
+   Session extension is only available via command line. This feature extends the session 
+   from the default 24 hours to 7 days starting since the current time.
+
+Stop a session::
+
+    don stop
+
+This immediately terminates the remote support session and cleans up all resources.
+
+Check for expired sessions::
+
+    don expire
+
+This command is automatically run by cron every hour to check if the session has expired.
+If the session has expired, it will be automatically stopped.
+
+Log examples::
 
-To terminate the session, click the :guilabel:`End session` button.
+    Mar 27 09:24:37 NethSec don: Remote support session started
+    Mar 27 09:24:54 NethSec don: Remote support session extended by 7 days
+    Mar 27 09:25:04 NethSec don: Remote support session stopped