/**
 * SSRF Guard — Safe URL Validation Utility
 *
 * Prevents Server-Side Request Forgery by:
 *  1. Enforcing HTTPS-only (no plain HTTP).
 *  2. Normalising encoded IPv4 forms (octal, hex, decimal integer, IPv4-mapped IPv6)
 *     to canonical dotted-decimal before rangechecking.
 *  3. Resolving the hostname for **both** A and AAAA families and rejecting
 *     requests to RFC 1918 private ranges, loopback, link-local, CGNAT,
 *     IPv6 link-local/ULA, and cloud metadata endpoints
 *     (AWS / GCP / Azure / Alibaba).
 *  4. Re-throwing on DNS failure rather than silently allowing the request.
 *
 * **DNS rebinding residual race:** `assertSafeUrl` validates the IP at the
 * moment of the lookup. If the resolver returns a public IP here and a private
 * IP at the actual `fetch()` call, the guard is bypassed. To eliminate the
 * race, use the companion `safeDownload` helper in `safeFetch.ts` which pins
 * the resolved IP onto the request via an undici Agent dispatcher.
 *
 * Usage:
 *   await assertSafeUrl(url);
 *   // ... or, for actual downloads: ...
 *   await safeDownload(url, { maxBytes, label });
 *
 * @module utils/ssrfGuard
 */
/**
 * Assert that `url` is safe to fetch server-side.
 *
 * @throws {Error} when the URL is non-HTTPS, parses as a blocked IP literal,
 *   or resolves (A or AAAA) to a blocked IP. **Also throws on DNS lookup
 *   failure** (the previous behaviour of silently allowing was a bypass —
 *   an attacker-controlled resolver could force NXDOMAIN here and a private
 *   IP at the actual fetch).
 */
export declare function assertSafeUrl(url: string): Promise<void>;
/**
 * Validate `url` and return the resolved IP that should be used for the
 * actual fetch (companion to `safeFetch.ts:safeDownload`).
 *
 * For IP-literal hosts, returns the normalised IP and family. For hostnames,
 * returns the first acceptable IP from the resolver. Same throw semantics as
 * {@link assertSafeUrl}.
 *
 * This is the canonical entry point for binary downloads where DNS-rebinding
 * pinning matters — see `safeFetch.ts`.
 */
export declare function validateAndResolveUrl(url: string): Promise<{
    url: string;
    ip: string;
    family: 4 | 6;
}>;