lan-address-gen

this tool (and lib) generates lan addresses using deterministic static hashing. it maps input strings to ip addresses within the 10.0.0.0/8 private ip range.

it has no non-native deps to run and only requires jest to run the test suite.

i use this as part of my homelab toolkit for static ip assignment.

how it works

1. takes an input string (and optional salt)
2. creates a sha-256 hash of the string
3. uses the last 24 bits of the hash to generate a number
4. maps this number to an ip in the 10.x.x.x range

note that if the --ping option is provided it will attempt to verify that it cannot contact the address via ping before returning the address. if it can, it will increment the ip address until it finds an available address and return that.

installation

global install:

npm install -g lan-address-gen

local install:

npm install lan-address-gen

usage

cli

lan-address-gen <input_string> [options]

options:
  --ping        check if the ip is in use and find an available one
  --verbose     show more details
  --help        display help
  --salt <salt> add some spice to your hash

simple:

lan-address-gen proxmox

10.248.60.218

specify a custom salt:

lan-address-gen proxmox --salt test

10.231.140.108

verbose with ping verification:

lan-address-gen proxmox --ping --verbose

Generated IP: 10.248.60.218
Checking for an available IP...
Available IP found: 10.248.60.218
10.248.60.218

module

const { stringToIp, ipToString } = require('lan-address-gen');

const ip = ipToString(stringToIp('proxmox', 'optional salt'));
console.log(ip); // outputs something like 10.123.45.67

you can also set a salt with the LAN_ADDRESS_SALT environment variable if you use the module programmatically.

development

run tests with:

npm test

here's what you should see:

🚀 testBasicFunctionality passed
Collision rate: 0.02%
🚀 testCollisions passed
Distribution range: 108
Min occurrences: 337, Max occurrences: 445
Average occurrences: 390.63
Chi-square value: 281.18
Approximate p-value: 0.1249
🚀 testDistribution passed
🚀 testIncrementIP passed
All tests completed

looks good, right?

notes

this is just for fun. in the real world, think about:

• hash collisions (they happen)
• your network's rules
• security stuff (predictable ips aren't always great)

use responsibly or irresponsibly

license

mit

contrib

prs welcome.