[bug] convert_called_station_id command fails silently, called_station_id remains unconverted

[pandafy]

Describe the bug

The convert_called_station_id management command does not convert the called_station_id
field in RADIUS accounting sessions. The called_station_id remains in its original
unconverted format (e.g., 00:27:22:F3:FA:F1:gw1.openwisp.org) after the command runs.

Root Cause

The file openwisp_radius/management/commands/base/convert_called_station_id.py uses
Exscript.protocols.telnetlib.Telnet as a context manager:

openwisp-radius/openwisp_radius/management/commands/base/convert_called_station_id.py

Line 26 in 46bda72

with telnetlib.Telnet(host, port, timeout=TELNET_CONNECTION_TIMEOUT) as tn:

However, Exscript.protocols.telnetlib.Telnet is a custom fork of Python's standard
telnetlib and does not implement the __enter__ and __exit__ dunder methods required
for context manager (with statement) support.

As a result:

• The Telnet connection to the OpenVPN management interface is never properly established
• The command exits silently without performing any conversion
• No exception is raised, making the failure difficult to detect

Note: Python's standard telnetlib.Telnet does support context managers, but
Exscript.protocols.telnetlib does not inherit this behavior as it is a separate
re-implementation.

Steps to Reproduce

1. Configure OPENWISP_RADIUS_CALLED_STATION_IDS in settings.py:

OPENWISP_RADIUS_CALLED_STATION_IDS = {
    "<organization_uuid>": {
        "openvpn_config": [
            {
                "host": "<openvpn_host>",
                "port": 7505,
            }
        ],
        "unconverted_ids": ["<called_station_id>"],
    }
}

2. Run the management command:

python manage.py convert_called_station_id

3. Check radacct — called_station_id remains unchanged.

Expected Behavior

The command should connect to the OpenVPN management interface via Telnet, retrieve the
correct called station ID, and update the called_station_id field in the RADIUS
accounting records accordingly.

Suggested Fix

Replace the with block with an explicit try/finally to ensure the Telnet connection is
properly opened and closed:

tn = telnetlib.Telnet(host, port, timeout=TELNET_CONNECTION_TIMEOUT)
try:
    # existing logic using tn
finally:
    tn.close()

[openwisp-companion]

Hi @omlahore 👋,

Thank you for opening PR #750 to address this issue!

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