Network Interface MQTT Toggle

This is an OpenWrt utility used to toggle network interfaces via MQTT messages.

The utility employs the mosquitto MQTT client to subscribe to a topic and toggle the state of a network interface based on the received messages.

⚠️ Disclaimer

Be careful when specifying a target network interface in your configuration, as you could potentially get locked out of your access point.
Always double-check your configuration before applying changes.

Build and installation

Important

The build process requires a running Docker daemon.

Additionally, devices running on Apple Silicon should enable Rosetta to build the package successfully.
Please refer to the official Docker documentation on how to enable Rosetta in Docker Desktop for macOS.

Tip

For instructions on manually building the package, refer to this wiki page.

Clone this repository via Git, then build the package by invoking the make utility on the Makefile within the .build directory:

make -f .build/Makefile

Once finished, the build process will result in an .ipk package in the .build directory.
Transfer a copy to the target device via SCP or any method of your choice, then install it from the shell of the device:

opkg update
opkg install ifmqtoggle_*_all.ipk

Configuration

The package configuration is managed through UCI and can be updated either through the CLI utility or by directly editing the configuration file found at /etc/config/ifmqtoggle.
A sample configuration section is provided when the package is installed.

Multiple interfaces can be managed simultaneously by defining multiple listener sections in the configuration.
Listeners will be started in the order they appear in the configuration.

The configuration options for each listener should specify the connection parameters to the MQTT broker and the name of the target network interface:

• enabled determines whether the listener is active; set to 1 to enable the listener, otherwise set to 0.
• iface is the name of the network interface that the listener will manage.
• mqtt_broker_host and mqtt_broker_port specify the address and port of the MQTT broker.
• mqtt_broker_retry_delay is the delay in seconds before retrying a failed connection to the MQTT broker; defaults to 5 seconds if unspecified.
• mqtt_topic is the MQTT topic that the listener will subscribe to.
• mqtt_username and mqtt_password are the credentials for the MQTT broker; leave empty if no authentication is required.
• mqtt_options are additional options for the MQTT client; these should be formatted as they would be on the command line for mosquitto_sub.

Note

If you plan on controlling more than one network interface coordinately by using the same MQTT topic for multiple listeners, ensure that each one has a unique client ID specified in the mqtt_options option in order to avoid conflicting message consumption. If no client ID is specified, unique IDs should be automatically generated based on the ID of each process.

For example, this is what a configuration file with two listeners could look like, with each listener specifying a unique client ID:

config listener 'guest'
        option enabled '1'
        option iface 'guest'
        # ... other options ...
        option mqtt_options '-i d98a71fe-0bdb-4515-b6f9-091c080d4ee4'

config listener 'wireguard'
        option enabled '1'
        option iface 'wg0'
        # ... other options ...
        option mqtt_options '-i 51f6dbd0-c10b-4ae7-9ef4-ab35cb3e56ed'

Usage

The utility can be managed as a service:

• Start the service: /etc/init.d/ifmqtoggle start
• Stop the service: /etc/init.d/ifmqtoggle stop
• Restart the service: /etc/init.d/ifmqtoggle restart or /etc/init.d/ifmqtoggle reload
• Check the status of the service: /etc/init.d/ifmqtoggle status
• Enable the service on boot: /etc/init.d/ifmqtoggle enable
• Disable the service from starting on boot: /etc/init.d/ifmqtoggle disable

Expected MQTT message format

The utility expects MQTT messages to be simple JSON objects with a boolean active field:

{ "active": true }

{ "active": false }

The value specified in the active field is used to update the state of the target network interface:

• true: the utility will attempt to enable the target network interface.
• false: the utility will attempt to disable the target network interface.

Please note that the utility will discard any message with an invalid or missing active field.
Any other fields present in the message will be ignored.