/**
 * SSRF guard — classifies an address (or hostname literal) as
 * private/loopback/link-local/cloud-metadata/CGNAT. Single source of truth
 * for address classification: `web.fetch` (classifier branch + per-hop
 * resolution check), `src/safety/classifier.ts`, and the legacy
 * `http.fetch` check (via {@link isBlockedAddress}) all delegate here.
 */
/**
 * Categorical address class returned by {@link classify} and
 * {@link classifyHost} when the input belongs to a non-public range.
 *
 * Mappings:
 * - `loopback`         — 127.0.0.0/8, IPv6 `::1`, and the
 *                         `localhost` / `ip6-localhost` hostname literals.
 * - `rfc1918`          — 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, and
 *                         IPv6 ULA `fc00::/7` (the IPv6 private-use range,
 *                         grouped here as RFC1918's IPv6 cousin).
 * - `ipv4-link-local`  — 169.254.0.0/16 except the cloud-metadata literal.
 * - `ipv6-link-local`  — `fe80::/10`.
 * - `cloud-metadata`   — `169.254.169.254` (IPv4 EC2/AWS, GCP, Azure
 *                         metadata) and `fd00:ec2::254` (IPv6 EC2 metadata).
 * - `cgnat`            — 100.64.0.0/10 (RFC 6598 carrier-grade NAT).
 */
export type AddressClass = "loopback" | "rfc1918" | "ipv4-link-local" | "ipv6-link-local" | "cloud-metadata" | "cgnat";
/** Result shape returned by {@link classify} and {@link classifyHost}. */
export interface AddressClassification {
    class: AddressClass;
}
/**
 * `true` iff `url` parses as an absolute URL with scheme `http:`/`https:`.
 * Single source of truth for the scheme allow-list so the safety classifier
 * and the fetch-core argument validator stay in sync.
 */
export declare function isAllowedScheme(url: string): boolean;
/**
 * Classify a literal IP address (IPv4 or IPv6).
 *
 * Returns `{ class }` when the address falls into one of the
 * {@link AddressClass} buckets, or `null` when the input is a
 * globally-routable address (or fails to parse as either family).
 *
 * The check is fully synchronous and never performs DNS.
 */
export declare function classify(ip: string): AddressClassification | null;
/**
 * Classify a hostname or IP literal without performing DNS resolution.
 *
 * - For literal IPv4/IPv6 addresses (with or without surrounding `[…]`
 *   brackets), this delegates to {@link classify}.
 * - For known-bad hostname literals (`localhost`, `localhost.localdomain`,
 *   `ip6-localhost`, `ip6-loopback`), this returns `{ class: "loopback" }`.
 * - For every other hostname, this returns `null` (the caller is
 *   responsible for the DNS-resolved second pass; see
 *   `src/tools/web/fetch-core.ts`).
 */
export declare function classifyHost(hostname: string): AddressClassification | null;
/**
 * Legacy boolean shape preserved for the existing `http.fetch` SSRF check.
 *
 * Returns `true` whenever {@link classifyHost} would return a non-null
 * classification, plus a small additional set of historically-blocked
 * ranges (currently `0.0.0.0/8`, the "this network" range) that are kept
 * for backward compatibility with the previous `http.ts` implementation
 * but are not enumerated in the public {@link AddressClass} list.
 */
export declare function isBlockedAddress(host: string): boolean;