Mirror: Best-effort discovery of the machine's local network using just Node.js dgram sockets
feat: Add CLI for testing (#3)
* Remove default assignment
* Add test CLI
* Add changeset
authored by
Phil Pluckthun
and committed by
GitHub
e5785771
3a03fb7b
+194
-13
+5
.changeset/plenty-ears-laugh.md
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.changeset/plenty-ears-laugh.md
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cli/package.json
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cli/package.json
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{
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"name": "lan-network-cli",
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"private": true,
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"version": "0.0.0",
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"main": "../dist/lan-network-cli.js",
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"types": "../dist/lan-network-cli.d.ts",
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"source": "../src/cli.ts",
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"exports": {
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".": {
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"types": "../dist/lan-network-cli.d.ts",
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"require": "../dist/lan-network-cli.js",
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"source": "../src/cli.ts"
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}
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}
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}
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package.json
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package.json
···
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"changeset:version": "changeset version && pnpm install --lockfile-only",
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"changeset:publish": "changeset publish"
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},
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"bin": {
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"lan-network": "./dist/lan-network-cli.js"
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},
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"exports": {
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".": {
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"types": "./dist/lan-network.d.ts",
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"types": "./dist/lan-network-subprocess.d.ts",
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"require": "./dist/lan-network-subprocess.js",
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"source": "./src/subprocess.ts"
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},
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"./cli": {
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"types": "./dist/lan-network-cli.d.ts",
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"require": "./dist/lan-network-cli.js",
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"source": "./src/cli.ts"
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},
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"./package.json": "./package.json"
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},
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src/cli.ts
+149
src/cli.ts
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#!/usr/bin/env node
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import type { GatewayAssignment } from './types';
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import {
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DEFAULT_ASSIGNMENT,
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interfaceAssignments,
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matchAssignment,
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} from './network';
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import { probeDefaultRoute } from './route';
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import { dhcpDiscover } from './dhcp';
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import { lanNetwork } from './index';
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type Mode = 'help' | 'dhcp' | 'probe' | 'fallback' | 'default';
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function help() {
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const output = [
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"Discover the machine's default gateway and local network IP (test utility)",
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'',
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'Usage',
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' $ lan-network',
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' $ lan-network --default',
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'',
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'Modes',
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' --probe Discover gateway via UDP4 socket to publicly routed address',
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' --dhcp Discover gateway via DHCPv4 discover broadcast',
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' --fallback Return highest-priority IPv4 network interface assignment',
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' --default Try the three above modes in order',
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' --help Print help output',
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].join('\n');
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console.log(output);
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}
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+
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async function dhcp() {
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const assignments = interfaceAssignments();
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if (!assignments.length) {
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console.error('No available network interface assignments');
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process.exit(1);
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}
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const discoveries = await Promise.allSettled(
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assignments.map(assignment => {
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// For each assignment, we send a DHCPDISCOVER packet to its network mask
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return dhcpDiscover(assignment);
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})
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);
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console.log(discoveries);
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let assignment: GatewayAssignment | null = null;
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for (const discovery of discoveries) {
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// The first discovered gateway is returned, if it matches an assignment
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if (discovery.status === 'fulfilled' && discovery.value) {
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const dhcpRoute = discovery.value;
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if ((assignment = matchAssignment(assignments, dhcpRoute))) {
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break;
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}
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}
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}
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if (assignment && assignment !== DEFAULT_ASSIGNMENT) {
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console.log(JSON.stringify(assignment, null, 2));
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process.exit(0);
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} else {
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console.error('No DHCP router was discoverable');
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process.exit(1);
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}
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}
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async function probe() {
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const assignments = interfaceAssignments();
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if (!assignments.length) {
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console.error('No available network interface assignments');
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process.exit(1);
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}
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try {
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const defaultRoute = await probeDefaultRoute();
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const assignment = matchAssignment(assignments, defaultRoute);
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if (assignment && assignment !== DEFAULT_ASSIGNMENT) {
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console.log(JSON.stringify(assignment, null, 2));
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process.exit(0);
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} else {
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console.error('No default gateway or route');
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process.exit(1);
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}
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} catch (error) {
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console.error('No default gateway or route');
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console.error(error);
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process.exit(1);
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}
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}
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async function fallback() {
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const assignments = interfaceAssignments();
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if (!assignments.length) {
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console.error('No available network interface assignments');
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process.exit(1);
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}
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const assignment = { ...assignments[0], gateway: null };
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console.log(JSON.stringify(assignment, null, 2));
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process.exit(0);
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}
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async function main() {
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const assignment = await lanNetwork();
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if (assignment !== DEFAULT_ASSIGNMENT) {
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console.log(JSON.stringify(assignment, null, 2));
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process.exit(0);
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} else {
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console.error('No default gateway, route, or DHCP router');
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process.exit(1);
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}
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}
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function cli() {
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let mode: Mode = 'default';
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parseArgs: for (let i = 1; i < process.argv.length; i++) {
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const arg = process.argv[i].trim().toLowerCase();
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switch (arg) {
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case '-h':
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case '--help':
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mode = 'help';
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break parseArgs;
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case '-d':
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case '--dhcp':
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mode = 'dhcp';
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break;
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case '-p':
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case '--probe':
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mode = 'probe';
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break;
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case '-f':
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case '--fallback':
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mode = 'fallback';
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break;
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default:
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if (arg.startsWith('-')) throw new TypeError(`Invalid flag: ${arg}`);
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}
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}
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switch (mode) {
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case 'help':
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return help();
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case 'dhcp':
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return dhcp();
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case 'probe':
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return probe();
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case 'fallback':
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return fallback();
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case 'default':
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return main();
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}
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}
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cli();
+1
-1
src/dhcp.ts
+1
-1
src/dhcp.ts
+5
-12
src/index.ts
+5
-12
src/index.ts
···
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import { spawnSync } from 'child_process';
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import { dhcpDiscover } from './dhcp';
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import { probeDefaultRoute } from './route';
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import { interfaceAssignments, matchAssignment } from './network';
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import {
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DEFAULT_ASSIGNMENT,
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interfaceAssignments,
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matchAssignment,
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} from './network';
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import type { GatewayAssignment } from './types';
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const DEFAULT_ASSIGNMENT: GatewayAssignment = {
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iname: 'lo0',
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address: '127.0.0.1',
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netmask: '255.0.0.0',
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family: 'IPv4',
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mac: '00:00:00:00:00:00',
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internal: true,
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cidr: '127.0.0.1/8',
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gateway: null,
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};
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export async function lanNetwork(): Promise<GatewayAssignment> {
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// Get IPv4 network assignments, sorted by:
+11
src/network.ts
+11
src/network.ts
···
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import os from 'node:os';
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import type { GatewayAssignment, NetworkAssignment } from './types';
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export const DEFAULT_ASSIGNMENT: GatewayAssignment = {
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iname: 'lo0',
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address: '127.0.0.1',
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netmask: '255.0.0.0',
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family: 'IPv4',
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mac: '00:00:00:00:00:00',
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internal: true,
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cidr: '127.0.0.1/8',
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gateway: null,
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};
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export const parseMacStr = (macStr: string): number[] =>
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macStr
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.split(':')