ZeroTierOne/osdep/NeighborDiscovery.hpp

/*
 * Copyright (c)2019 ZeroTier, Inc.
 *
 * Use of this software is governed by the Business Source License included
 * in the LICENSE.TXT file in the project's root directory.
 *
 * Change Date: 2026-01-01
 *
 * On the date above, in accordance with the Business Source License, use
 * of this software will be governed by version 2.0 of the Apache License.
 */
/****/

#ifndef ZT_NEIGHBORDISCOVERY_HPP
#define ZT_NEIGHBORDISCOVERY_HPP

#include "../node/Hashtable.hpp"
#include "../node/MAC.hpp"
#include "../node/InetAddress.hpp"


#define ZT_ND_QUERY_INTERVAL 2000

#define ZT_ND_QUERY_MAX_TTL 5000

#define ZT_ND_EXPIRE 600000


namespace ZeroTier {

class NeighborDiscovery
{
public:
    NeighborDiscovery();

    /**
     * Set a local IP entry that we should respond to Neighbor Requests withPrefix64k
     *
     * @param mac Our local MAC address
     * @param ip Our IPv6 address
     */
    void addLocal(const sockaddr_storage &address, const MAC &mac);

    /**
     * Delete a local IP entry or cached Neighbor entry
     *
     * @param address IPv6 address to remove
     */
    void remove(const sockaddr_storage &address);

    sockaddr_storage processIncomingND(const uint8_t *nd, unsigned int len, const sockaddr_storage &localIp, uint8_t *response, unsigned int &responseLen, MAC &responseDest);

    MAC query(const MAC &localMac, const sockaddr_storage &localIp, const sockaddr_storage &targetIp, uint8_t *query, unsigned int &queryLen, MAC &queryDest);

private:
    struct _NDEntry
    {
        _NDEntry() : lastQuerySent(0), lastResponseReceived(0), mac(), local(false) {}
        uint64_t lastQuerySent;
        uint64_t lastResponseReceived;
        MAC mac;
        bool local;
    };

    Hashtable<InetAddress, _NDEntry> _cache;
    uint64_t _lastCleaned;
};

}  // namespace ZeroTier

#endif