#pragma once

#include "envoy/network/connection.h"

#include "absl/types/optional.h"

namespace Envoy {

namespace Network {

/**

 * Hash policy for transport layer protocol.

 */

class HashPolicy {

public:

  /**

   * @param connection is the raw downstream connection. Different implementations of HashPolicy can

   *        compute hashes based on different data accessible from the connection (e.g. IP address,

   *        filter state, etc.).

   * @return absl::optional<uint64_t> an optional hash value to route on. A hash value might not be

   * returned if the hash policy implementation doesn't find the expected data in the connection

   * (e.g. IP address is null, filter state is not populated, etc.).

   */

  virtual absl::optional<uint64_t> generateHash(const Network::Connection& connection) const PURE;

};

} // namespace Network

} // namespace Envoy