dhcp2veyon

This system aims to convert DHCP lease data into a JSON format compatible with Veyon configuration. The tool allows filtering data by network and room, and it can also be configured to display only the room to which a specific IP belongs.

Features

• Conversion of DHCP lease files to Veyon JSON format: From a DHCP lease file, the system generates a JSON file in the format expected by Veyon.
• Filtering by network (CIDR): You can specify one or more CIDR networks (e.g., 192.168.1.0/24) to filter the machines and rooms to be included in the configuration.
• Filtering by IP address: With the -a option, you can filter results to include only the room where the provided IP is located.
• Excluding other rooms: When the -a option is used, the system ensures that only the hosts in the room associated with the provided IP are displayed, excluding all other rooms.
• Empty return in case of invalid IP: When a provided IP does not belong to any network and the --all option is not active, the system returns an empty configuration while preserving the Veyon JSON structure with an empty JsonStoreArray field.

Installation

Requirements

• Python 3.6 or higher

Dependency installation

There are no dependencies.

DHCP lease file

The system input must be a DHCP lease file, which can be obtained directly from a DHCP server or exported from a system that provides it. The input can be either a local file path or a URL.

Using the HTTP version

The HTTP version is the most practical way to obtain the Veyon configuration to be deployed on the teacher’s computer.

Editing default values

• Make a copy of the settings.py-example file and rename it to settings.py;
• Edit the settings.py file according to your network characteristics.

Starting the HTTP server

The following code shows an example of how to start the HTTP server on port 80 (replace the port if needed):

VEYON_HTTP_PORT=80 python3 http_server.py

List of available URLs

• /veyon: Returns the configuration of the room based on the IP that accessed the resource (used for the teacher’s computer).
• /veyon/all: Returns the configuration of all configured rooms.

Setting up the teacher’s computer

You need to create a script that periodically updates the Veyon configuration.

On Windows

Use Task Scheduler to run the following PowerShell script as administrator:

iwr http://my-server/veyon -OutFile C:\WINDOWS\Temp\veyon.json
& "C:\Program Files\Veyon\veyon-cli.exe" config import C:\WINDOWS\Temp\veyon.json
Restart-Service -Name VeyonService

On Linux

Use cron as root to run the following bash script:

VEYON_CONFIG_FILE="/tmp/.config.json"
wget "http://my-server/veyon" -O $VEYON_CONFIG_FILE -q
veyon-cli config import $VEYON_CONFIG_FILE
systemctl restart veyon

Using the CLI version

The script can be executed as follows:

python3 dhcp_to_veyon.py -f "<path_to_dhcpd.leases>" -n "<network1>" -n "<network2>" -r "<room1>" -r "<room2>" [-a "<ip_address>"] [--all]

Parameters

• -f <file_path>: Path to the DHCP lease file or URL containing the lease data.
• -n <network>: Network address in CIDR format (e.g.,192.168.1.0/24). Can be used multiple times to specify several networks.
• -r <room>: Room or group name. Can be used multiple times to associate multiple networks with different rooms.
• -a <ip_address>: Filter for a specific IP. If provided, the script will return only the configuration of the room where the IP is present.
• --all: If provided, it will include all rooms, even if the filtered IP does not belong to any specified network.

Usage examples

1. Simple DHCP-to-Veyon JSON conversion::

python3 dhcp_to_veyon.py -f "dhcpd.leases" -n "10.1.2.0/24" -n "10.1.3.0/24" -r "Room 2" -r "Room 3"

This will generate a JSON file with configurations for the networks 10.1.2.0/24 and 10.1.3.0/24, associated with rooms "Room 2" and "Room 3".

2. Filtering by IP (returns the room with the provided IP):

python3 dhcp_to_veyon.py -f "dhcpd.leases" -n "10.1.2.0/24" -n "10.1.3.0/24" -r "Room 2" -r "Room 3" -a "10.1.2.200"

This will return only the machines in "Room 2", excluding any machines associated with other networks or rooms.

3. When the provided IP does not belong to any network and --all is not provided:

python3 dhcp_to_veyon.py -f "dhcpd.leases" -n "10.1.2.0/24" -n "10.1.3.0/24" -r "Room 2" -r "Room 3" -a "10.1.4.200"

This will result in an empty configuration with the Veyon structure and an empty JsonStoreArray.

4. With the --all option, all rooms will be included, even if the IP is not found in any network:

python3 dhcp_to_veyon.py -f "dhcpd.leases" -n "10.1.2.0/24" -n "10.1.3.0/24" -r "Room 2" -r "Room 3" -a "10.1.4.200" --all

This will return all rooms, including "Room 2" and "Room 3", even if IP 10.1.4.200 does not belong to any network.