@kanadi/core/src/ban/ip-utils.ts

Multi-Layer CAPTCHA Framework with customizable validators and challenge bundles

import { createLogger } from "../utils/logger";

const logger = createLogger("IPUtils");

export function parseCIDR(cidr: string): { network: string; prefix: number; start: bigint; end: bigint } {
	const [ip, prefixStr] = cidr.split("/");
	const prefix = parseInt(prefixStr);

	if (!ip || isNaN(prefix) || prefix < 0 || prefix > 32) {
		throw new Error(`Invalid CIDR notation: ${cidr}`);
	}

	const ipNum = ipToNumber(ip);
	const mask = BigInt(0xFFFFFFFF) << BigInt(32 - prefix);
	const network = ipNum & mask;
	const broadcast = network | (~mask & BigInt(0xFFFFFFFF));

	return {
		network: numberToIP(network),
		prefix,
		start: network,
		end: broadcast,
	};
}

export function ipToNumber(ip: string): bigint {
	const parts = ip.split(".").map(Number);
	if (parts.length !== 4 || parts.some(p => p < 0 || p > 255)) {
		throw new Error(`Invalid IP address: ${ip}`);
	}
	return BigInt(
		(parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8) | parts[3]
	) >>> BigInt(0);
}

export function numberToIP(num: bigint): string {
	const n = Number(num);
	return [
		(n >>> 24) & 0xFF,
		(n >>> 16) & 0xFF,
		(n >>> 8) & 0xFF,
		n & 0xFF
	].join(".");
}

export function isIPInCIDR(ip: string, cidr: string): boolean {
	try {
		const ipNum = ipToNumber(ip);
		const { start, end } = parseCIDR(cidr);
		return ipNum >= start && ipNum <= end;
	} catch {
		return false;
	}
}

export interface ASNPrefix {
	prefix: string;
	ip: string;
	cidr: number;
	name: string;
	description: string;
}

export async function fetchASNPrefixes(asn: string): Promise<ASNPrefix[]> {
	const asnNumber = asn.replace(/^AS/i, "");

	try {
		const response = await fetch(`https://api.bgpview.io/asn/${asnNumber}/prefixes`);

		if (!response.ok) {
			throw new Error(`BGPView API error: ${response.status}`);
		}

		const data = await response.json();

		const prefixes: ASNPrefix[] = [];

		if (data.data?.ipv4_prefixes) {
			for (const prefix of data.data.ipv4_prefixes) {
				prefixes.push({
					prefix: prefix.prefix,
					ip: prefix.ip || prefix.prefix.split("/")[0],
					cidr: parseInt(prefix.prefix.split("/")[1]),
					name: prefix.name || `AS${asnNumber}`,
					description: prefix.description || `ASN ${asnNumber} prefix`,
				});
			}
		}

		return prefixes;
	} catch (error) {
		logger.error(`Failed to fetch ASN ${asnNumber} prefixes`, error);
		throw error;
	}
}