Tailutils

What is tailutils?

tailutils is a Go library designed to simplify interactions with Tailscale network interfaces on a machine. It provides a collection of functions to manage and interact with Tailscale interfaces, helping developers to easily work with Tailscale VPN connections. Currently, tailutils offers the following key functions:

Key Functions:

• HasTailscaleIP: Checks whether the machine has an active Tailscale interface (IPv4 or IPv6).
• GetTailscaleIP: Retrieves the IPv4 address assigned to the Tailscale interface.
• GetTailscaleIP6: Retrieves the IPv6 address assigned to the Tailscale interface.
• GetInterfaceName: Retrieves the name of the network interface associated with a given Tailscale IP address.

These utilities are particularly useful for applications that need to:

• Determine if the machine is connected to a Tailscale VPN.
• Retrieve the Tailscale IP addresses for network communications, logging, or configuration purposes.

How to Use tailutils

Installation

You can add tailutils to your Go project by running:

go get github.com/tailsecurity/tailutils

Usage Example

Below is an example of how you can use tailutils in your Go application to interact with Tailscale interfaces.

package main

import (
    "fmt"
    "log"
    "github.com/tailsecurity/tailutils"
)

func main() {
    // Check if the machine has a Tailscale IP (either IPv4 or IPv6)
    hasTailscale, err := tailutils.HasTailscaleIP()
    if err != nil {
        log.Fatalf("Error checking Tailscale IP: %v", err)
    }
    if hasTailscale {
        fmt.Println("Tailscale interface detected.")
    } else {
        fmt.Println("No Tailscale interface detected.")
    }

    // Get the Tailscale IPv4 address
    ipv4, err := tailutils.GetTailscaleIP()
    if err != nil {
        log.Printf("Error getting Tailscale IPv4 address: %v", err)
    } else {
        fmt.Printf("Tailscale IPv4 address: %s\n", ipv4)
    }

    // Get the Tailscale IPv6 address
    ipv6, err := tailutils.GetTailscaleIP6()
    if err != nil {
        log.Printf("Error getting Tailscale IPv6 address: %v", err)
    } else {
        fmt.Printf("Tailscale IPv6 address: %s\n", ipv6)
    }

    // Get the name of the network interface for a given Tailscale IP address
    interfaceName, err := tailutils.GetInterfaceName(ipv4)
    if err != nil {
        log.Printf("Error getting interface name: %v", err)
    } else {
        fmt.Printf("Interface name: %s\n", interfaceName)
    }

    // Same thing, but for IPv6
    interfaceName6, err := tailutils.GetInterfaceName(ipv6)
    if err != nil {
        log.Printf("Error getting interface name: %v", err)
    } else {
        fmt.Printf("Interface name: %s\n", interfaceName6)
    }
}

Features

• IPv4 and IPv6 Support: tailutils allows you to work with both IPv4 and IPv6 addresses assigned to Tailscale interfaces.
• Network Interface Abstraction: By abstracting network operations, tailutils simplifies working with Go's net package, making it easier to manage network interfaces and IP address parsing.

API Reference

• func HasTailscaleIP() (bool, error): Checks if the machine has an active Tailscale IP address (either IPv4 or IPv6).
• func GetTailscaleIP() (string, error): Retrieves the IPv4 address of the Tailscale interface.
• func GetTailscaleIP6() (string, error): Retrieves the IPv6 address of the Tailscale interface.
• func GetInterfaceName(ip string) (string, error): Retrieves the name of the network interface for the given Tailscale IP address.

Why use tailutils?

Managing network interfaces and parsing IP ranges can be intricate and error-prone. tailutils abstracts these complexities, offering a straightforward API to interact with Tailscale interfaces reliably. If you're building an application that needs to determine whether it is connected to a Tailscale VPN or wants to retrieve Tailscale IP addresses for various purposes, tailutils provides a clean and easy-to-use solution.

Projects using tailutils

• Padserve - The server component of a secure and private messaging system for Tailscale users.
• Padclient - The client component of a secure and private messaging system for Tailscale users.

Want your project listed here? Submit a Pull Request!

Contributing

We welcome contributions to tailutils! Please refer to the CONTRIBUTING.md file for more information.

License

tailutils is licensed under the MIT License. You are free to use, modify, and distribute this library as long as you adhere to the terms of the MIT License.

Contact

If you have any questions, feel free to reach out via GitHub, or you can submit an issue directly in the repository.

Happy Tailscale hacking!