/**
 * `normalizeIpForBucketKey` — THE cross-repo normalizer for turning a raw
 * client-IP candidate (`x-forwarded-for` hop, socket remote address, proxy
 * header) into a stable rate-limit / dedup bucket key.
 *
 * WHY IT LIVES HERE: producer and consumer sit in DIFFERENT repos (the app
 * emits the candidate, the hub buckets it) and each had grown its own
 * normalizer. They disagreed — one unwrapped `::ffff:1.2.3.4` to the bare
 * IPv4 and stripped `%zone`, the other kept the zone and only lower-cased the
 * mapped form — so ONE visitor could land in TWO buckets depending on which
 * side normalized. Both repos already depend on this package, and
 * `./chat-protocol` is its server-safe subpath (no React, no browser APIs),
 * so this is the one place both sides can share.
 *
 * Contract:
 *   - input longer than `IP_BUCKET_KEY_MAX_LENGTH` → `null` (an unbounded
 *     header must never become an unbounded map key);
 *   - `[…]` brackets and a trailing `]:port` are stripped, as is a bare
 *     `:port` on an IPv4 (`203.0.113.4:8080`) — an unbracketed IPv6 with a
 *     bare port stays ambiguous and is not stripped;
 *   - a `%zone` suffix is stripped (link-local scope is per-host, not part of
 *     the peer's identity);
 *   - IPv4-mapped IPv6 (`::ffff:203.0.113.4`) collapses to the bare IPv4, so
 *     the same peer buckets identically over either stack;
 *   - IPv6 is lower-cased;
 *   - IPv4 octets are range-checked and REJECTED when zero-padded (`.04`
 *     would otherwise bucket separately from `.4`), and IPv6 is
 *     charset/shape-checked (one `::` at most, ≤8 groups, an embedded IPv4
 *     only in the last group, no dangling separator); anything else returns
 *     `null` rather than a junk bucket key.
 *
 * It does NOT canonicalize IPv6 zero-compression (`2001:db8::1` vs
 * `2001:0db8:0:0:0:0:0:1`) — peers do not spell their own address two ways
 * within one deployment, and a full expander is more surface than the bucket
 * key warrants.
 */
/** Longest accepted candidate. A full IPv6 + zone fits well inside this. */
export declare const IP_BUCKET_KEY_MAX_LENGTH = 64;
/**
 * Normalize one IP candidate to its canonical bucket key, or `null` when the
 * value is not a usable address.
 */
export declare function normalizeIpForBucketKey(value: string): string | null;
//# sourceMappingURL=ip-normalize.d.ts.map