flextoolnetbird

flextool

Proof-of-concept utility to rebroadcast FlexRadio Discovery Packets to NetBird VPN users.

Overview

flextool is designed to run on a Linux machine located on the same subnet as a FlexRadio Signature Series Radio.

It captures VITA 49 Discovery Packets from the local network and retransmits them to VPN users connected through a NetBird Management Server. This enables FlexRadio clients running remotely (over NetBird) to detect and connect to radios as if they were on the same LAN.

Requirements

• Go 1.22+
• libpcap-dev (or the equivalent package for your OS)

Building

Clone and build:

go mod tidy
go build

Configuration

Create a .flextool configuration file with settings appropriate for your environment.

The tool syncs NetBird VPN users and their assigned IP addresses into a local SQLite database. These IPs are then used as retransmission targets for FlexRadio discovery packets.

Usage

Sync NetBird VPN Users

Synchronize VPN users and their client IPs from the NetBird Management API.

flextool sync -d

The -d flag clears the database before inserting the updated list of VPN client IPs.

Listen & Re-broadcast

Listen for FlexRadio discovery broadcasts on the LAN and retransmit them to all NetBird VPN users:

flextool listen

Info & Debugging

List network interfaces:

flextool info -l

Show details for a specific interface:

flextool info -g eth0

Read a PCAP file and retransmit FlexRadio packets:

flextool pcap