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 *     notice, this list of conditions and the following disclaimer in the
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 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
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/**
 * @file
 *   This file includes definitions for infrastructure network interface.
 *
 */

#ifndef INFRA_IF_HPP_
#define INFRA_IF_HPP_

#include "openthread-core-config.h"

#if OPENTHREAD_CONFIG_BORDER_ROUTING_ENABLE

#include <openthread/platform/infra_if.h>

#include "common/data.hpp"
#include "common/error.hpp"
#include "common/locator.hpp"
#include "common/string.hpp"
#include "net/ip6.hpp"

namespace ot {
namespace BorderRouter {

/**
 * Represents the infrastructure network interface on a border router.
 *
 */
class InfraIf : public InstanceLocator
{
public:
    static constexpr uint16_t kInfoStringSize = 20; ///< Max chars for the info string (`ToString()`).

    typedef String<kInfoStringSize> InfoString;  ///< String type returned from `ToString()`.
    typedef Data<kWithUint16Length> Icmp6Packet; ///< An IMCPv6 packet (data containing the IP payload)

    /**
     * Initializes the `InfraIf`.
     *
     * @param[in]  aInstance  A OpenThread instance.
     *
     */
    explicit InfraIf(Instance &aInstance);

    /**
     * Initializes the `InfraIf`.
     *
     * @param[in]  aIfIndex        The infrastructure interface index.
     *
     * @retval  kErrorNone         Successfully initialized the `InfraIf`.
     * @retval  kErrorInvalidArgs  The index of the infra interface is not valid.
     * @retval  kErrorInvalidState The `InfraIf` is already initialized.
     *
     */
    Error Init(uint32_t aIfIndex);

    /**
     * Deinitilaizes the `InfraIf`.
     *
     */
    void Deinit(void);

    /**
     * Indicates whether or not the `InfraIf` is initialized.
     *
     * @retval TRUE    The `InfraIf` is initialized.
     * @retval FALSE   The `InfraIf` is not initialized.
     *
     */
    bool IsInitialized(void) const { return mInitialized; }

    /**
     * Indicates whether or not the infra interface is running.
     *
     * @retval TRUE   The infrastructure interface is running.
     * @retval FALSE  The infrastructure interface is not running.
     *
     */
    bool IsRunning(void) const { return mIsRunning; }

    /**
     * Returns the infrastructure interface index.
     *
     * @returns The interface index or zero if not initialized.
     *
     */
    uint32_t GetIfIndex(void) const { return mIfIndex; }

    /**
     * Sets the infrastructure interface index.
     *
     * @param[in]  aIfIndex        The infrastructure interface index.
     *
     */
    void SetIfIndex(uint32_t aIfIndex) { mIfIndex = aIfIndex; }

    /**
     * Indicates whether or not the infra interface has the given IPv6 address assigned.
     *
     * MUST be used when interface is initialized.
     *
     * @param[in]  aAddress       The IPv6 address.
     *
     * @retval TRUE   The infrastructure interface has @p aAddress.
     * @retval FALSE  The infrastructure interface does not have @p aAddress.
     *
     */
    bool HasAddress(const Ip6::Address &aAddress) const;

    /**
     * Sends an ICMPv6 Neighbor Discovery packet on the infrastructure interface.
     *
     * MUST be used when interface is initialized.
     *
     * @param[in]  aPacket        The ICMPv6 packet to send.
     * @param[in]  aDestination   The destination address.
     *
     * @retval kErrorNone    Successfully sent the ICMPv6 message.
     * @retval kErrorFailed  Failed to send the ICMPv6 message.
     *
     */
    Error Send(const Icmp6Packet &aPacket, const Ip6::Address &aDestination) const;

    /**
     * Processes a received ICMPv6 Neighbor Discovery packet from an infrastructure interface.
     *
     * @param[in]  aIfIndex       The infrastructure interface index on which the ICMPv6 message is received.
     * @param[in]  aSource        The IPv6 source address.
     * @param[in]  aPacket        The ICMPv6 packet.
     *
     */
    void HandledReceived(uint32_t aIfIndex, const Ip6::Address &aSource, const Icmp6Packet &aPacket);

    /**
     * Sends a request to discover the NAT64 prefix on the infrastructure interface.
     *
     * @note  This method MUST be used when interface is initialized.
     *
     * @retval  kErrorNone    Successfully request NAT64 prefix discovery.
     * @retval  kErrorFailed  Failed to request NAT64 prefix discovery.
     *
     */
    Error DiscoverNat64Prefix(void) const;

    /**
     * Processes the discovered NAT64 prefix.
     *
     * @param[in]  aIfIndex    The infrastructure interface index on which the host address is received.
     * @param[in]  aPrefix     The NAT64 prefix on the infrastructure link.
     *
     */
    void DiscoverNat64PrefixDone(uint32_t aIfIndex, const Ip6::Prefix &aPrefix);

    /**
     * Handles infrastructure interface state changes.
     *
     * @param[in]  aIfIndex         The infrastructure interface index.
     * @param[in]  aIsRunning       A boolean that indicates whether the infrastructure interface is running.
     *
     * @retval  kErrorNone          Successfully updated the infra interface status.
     * @retval  kErrorInvalidState  The `InfraIf` is not initialized.
     * @retval  kErrorInvalidArgs   The @p IfIndex does not match the interface index of `InfraIf`.
     *
     */
    Error HandleStateChanged(uint32_t aIfIndex, bool aIsRunning);

    /**
     * Converts the `InfraIf` to a human-readable string.
     *
     * @returns The string representation of `InfraIf`.
     *
     */
    InfoString ToString(void) const;

private:
    bool     mInitialized : 1;
    bool     mIsRunning : 1;
    uint32_t mIfIndex;
};

} // namespace BorderRouter
} // namespace ot

#endif // OPENTHREAD_CONFIG_BORDER_ROUTING_ENABLE

#endif // INFRA_IF_HPP_