/// <reference types="node" />
import Address from './address';
interface ParseUdpFrame {
    rsv: Buffer;
    frag: number;
    address: Address;
    data: Buffer;
}
/**
 * UdpRelay will create a UDP relay server,
 * and it happens only once because of the singleton design pattern
 */
declare class UdpRelay {
    /**
     * Save the instance for further use
     */
    private static instance;
    /**
     * Datagram socket
     */
    private udpRelay;
    private constructor();
    /**
     * The static method that controls the access to the UdpRelay instance
     * @param port - Port to bind socket to
     * @returns UdpRelay
     */
    static getInstance(port: number): UdpRelay;
    /**
     * Creates a SOCKS UDP frame
     * @param address - The address to forward data to
     * @param data - The data to be forwarded
     * @param frag - The fragment number
     * @returns Buffer
     */
    static createUdpFrame(address: Address, data: Buffer, frag?: number): Buffer;
    /**
     * Parses a SOCKS UDP frame
     * @param buffer - data to be parse
     * @returns ParseUdpFrame
     */
    static parseUdpFrame(buffer: Buffer): ParseUdpFrame;
    /**
     * Close Relay's socket
     * @param callback - Called when the socket has been closed
     */
    close(callback?: () => void): void;
}
export default UdpRelay;