/*
 *  Copyright (c) 2016, The OpenThread Authors.
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the copyright holder nor the
 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @file
 *   This file includes definitions for MLE functionality required by the Thread Router and Leader roles.
 */

#ifndef MLE_ROUTER_FTD_HPP_
#define MLE_ROUTER_FTD_HPP_

#include "openthread-core-config.h"

#include <openthread/thread_ftd.h>

#include "coap/coap.hpp"
#include "coap/coap_message.hpp"
#include "common/timer.hpp"
#include "common/trickle_timer.hpp"
#include "mac/mac_types.hpp"
#include "meshcop/meshcop_tlvs.hpp"
#include "net/icmp6.hpp"
#include "net/udp6.hpp"
#include "thread/child_table.hpp"
#include "thread/mle.hpp"
#include "thread/mle_tlvs.hpp"
#include "thread/router_table.hpp"
#include "thread/thread_tlvs.hpp"
#include "thread/topology.hpp"

namespace ot {
namespace Mle {

/**
 * @addtogroup core-mle-router
 *
 * @brief
 *   This module includes definitions for MLE functionality required by the Thread Router and Leader roles.
 *
 * @{
 */

/**
 * This class implements MLE functionality required by the Thread Router and Leader roles.
 *
 */
class MleRouter : public Mle
{
    friend class Mle;
    friend class ot::Instance;

public:
    /**
     * This constructor initializes the object.
     *
     * @param[in]  aInstance     A reference to the OpenThread instance.
     *
     */
    explicit MleRouter(Instance &aInstance);

    /**
     * This method indicates whether or not the device is router-eligible.
     *
     * @retval true   If device is router-eligible.
     * @retval false  If device is not router-eligible.
     *
     */
    bool IsRouterEligible(void) const;

    /**
     * This method sets whether or not the device is router-eligible.
     *
     * If @p aEligible is false and the device is currently operating as a router, this call will cause the device to
     * detach and attempt to reattach as a child.
     *
     * @param[in]  aEligible  TRUE to configure device router-eligible, FALSE otherwise.
     *
     * @retval OT_ERROR_NONE         Successfully set the router-eligible configuration.
     * @retval OT_ERROR_NOT_CAPABLE  The device is not capable of becoming a router.
     *
     */
    otError SetRouterEligible(bool aEligible);

    /**
     * This method indicates whether a node is the only router on the network.
     *
     * @retval TRUE   It is the only router in the network.
     * @retval FALSE  It is a child or is not a single router in the network.
     *
     */
    bool IsSingleton(void);

    /**
     * This method generates an Address Solicit request for a Router ID.
     *
     * @param[in]  aStatus  The reason for requesting a Router ID.
     *
     * @retval OT_ERROR_NONE           Successfully generated an Address Solicit message.
     * @retval OT_ERROR_NOT_CAPABLE    Device is not capable of becoming a router
     * @retval OT_ERROR_INVALID_STATE  Thread is not enabled
     *
     */
    otError BecomeRouter(ThreadStatusTlv::Status aStatus);

    /**
     * This method causes the Thread interface to become a Leader and start a new partition.
     *
     * @retval OT_ERROR_NONE           Successfully become a Leader and started a new partition.
     * @retval OT_ERROR_NOT_CAPABLE    Device is not capable of becoming a leader
     * @retval OT_ERROR_INVALID_STATE  Thread is not enabled
     *
     */
    otError BecomeLeader(void);

    /**
     * This method returns the Leader Weighting value for this Thread interface.
     *
     * @returns The Leader Weighting value for this Thread interface.
     *
     */
    uint8_t GetLeaderWeight(void) const { return mLeaderWeight; }

    /**
     * This method sets the Leader Weighting value for this Thread interface.
     *
     * @param[in]  aWeight  The Leader Weighting value.
     *
     */
    void SetLeaderWeight(uint8_t aWeight) { mLeaderWeight = aWeight; }

    /**
     * This method returns the fixed Partition Id of Thread network partition for certification testing.
     *
     * @returns The Partition Id for this Thread network partition.
     *
     */
    uint32_t GetLeaderPartitionId(void) const { return mFixedLeaderPartitionId; }

    /**
     * This method sets the fixed Partition Id for Thread network partition for certification testing.
     *
     * @param[in]  aPartitionId  The Leader Partition Id.
     *
     */
    void SetLeaderPartitionId(uint32_t aPartitionId) { mFixedLeaderPartitionId = aPartitionId; }

    /**
     * This method sets the preferred Router Id. Upon becoming a router/leader the node
     * attempts to use this Router Id. If the preferred Router Id is not set or if it
     * can not be used, a randomly generated router Id is picked.
     * This property can be set when he device role is detached or disabled.
     *
     * @param[in]  aRouterId             The preferred Router Id.
     *
     * @retval OT_ERROR_NONE          Successfully set the preferred Router Id.
     * @retval OT_ERROR_INVALID_STATE Could not set (role is other than detached and disabled)
     *
     */
    otError SetPreferredRouterId(uint8_t aRouterId);

    /**
     * This method gets the Partition Id which the device joined successfully once.
     *
     */
    uint32_t GetPreviousPartitionId(void) const { return mPreviousPartitionId; }

    /**
     * This method sets the Partition Id which the device joins successfully.
     *
     * @param[in]  aPartitionId   The Partition Id.
     *
     */
    void SetPreviousPartitionId(uint32_t aPartitionId) { mPreviousPartitionId = aPartitionId; }

    /**
     * This method sets the Router Id.
     *
     * @param[in]  aRouterId   The Router Id.
     *
     */
    void SetRouterId(uint8_t aRouterId);

    /**
     * This method returns the next hop towards an RLOC16 destination.
     *
     * @param[in]  aDestination  The RLOC16 of the destination.
     *
     * @returns A RLOC16 of the next hop if a route is known, kInvalidRloc16 otherwise.
     *
     */
    uint16_t GetNextHop(uint16_t aDestination);

    /**
     * This method returns the NETWORK_ID_TIMEOUT value.
     *
     * @returns The NETWORK_ID_TIMEOUT value.
     *
     */
    uint8_t GetNetworkIdTimeout(void) const { return mNetworkIdTimeout; }

    /**
     * This method sets the NETWORK_ID_TIMEOUT value.
     *
     * @param[in]  aTimeout  The NETWORK_ID_TIMEOUT value.
     *
     */
    void SetNetworkIdTimeout(uint8_t aTimeout) { mNetworkIdTimeout = aTimeout; }

    /**
     * This method returns the route cost to a RLOC16.
     *
     * @param[in]  aRloc16  The RLOC16 of the destination.
     *
     * @returns The route cost to a RLOC16.
     *
     */
    uint8_t GetRouteCost(uint16_t aRloc16) const;

    /**
     * This method returns the link cost to the given Router.
     *
     * @param[in]  aRouterId  The Router ID.
     *
     * @returns The link cost to the Router.
     *
     */
    uint8_t GetLinkCost(uint8_t aRouterId);

    /**
     * This method returns the minimum cost to the given router.
     *
     * @param[in]  aRloc16  The short address of the given router.
     *
     * @returns The minimum cost to the given router (via direct link or forwarding).
     *
     */
    uint8_t GetCost(uint16_t aRloc16);

    /**
     * This method returns the ROUTER_SELECTION_JITTER value.
     *
     * @returns The ROUTER_SELECTION_JITTER value.
     *
     */
    uint8_t GetRouterSelectionJitter(void) const { return mRouterSelectionJitter; }

    /**
     * This method sets the ROUTER_SELECTION_JITTER value.
     *
     * @returns The ROUTER_SELECTION_JITTER value.
     *
     */
    otError SetRouterSelectionJitter(uint8_t aRouterJitter);

    /**
     * This method returns the current router selection jitter timeout value.
     *
     * @returns The current router selection jitter timeout value.
     *
     */
    uint8_t GetRouterSelectionJitterTimeout(void) const { return mRouterSelectionJitterTimeout; }

    /**
     * This method returns the ROUTER_UPGRADE_THRESHOLD value.
     *
     * @returns The ROUTER_UPGRADE_THRESHOLD value.
     *
     */
    uint8_t GetRouterUpgradeThreshold(void) const { return mRouterUpgradeThreshold; }

    /**
     * This method sets the ROUTER_UPGRADE_THRESHOLD value.
     *
     * @returns The ROUTER_UPGRADE_THRESHOLD value.
     *
     */
    void SetRouterUpgradeThreshold(uint8_t aThreshold) { mRouterUpgradeThreshold = aThreshold; }

    /**
     * This method returns the ROUTER_DOWNGRADE_THRESHOLD value.
     *
     * @returns The ROUTER_DOWNGRADE_THRESHOLD value.
     *
     */
    uint8_t GetRouterDowngradeThreshold(void) const { return mRouterDowngradeThreshold; }

    /**
     * This method sets the ROUTER_DOWNGRADE_THRESHOLD value.
     *
     * @returns The ROUTER_DOWNGRADE_THRESHOLD value.
     *
     */
    void SetRouterDowngradeThreshold(uint8_t aThreshold) { mRouterDowngradeThreshold = aThreshold; }

    /**
     * This method removes a link to a neighbor.
     *
     * @param[in]  aNeighbor  A reference to the neighbor object.
     *
     */
    void RemoveNeighbor(Neighbor &aNeighbor);

    /**
     * This method restores children information from non-volatile memory.
     *
     */
    void RestoreChildren(void);

    /**
     * This method remove a stored child information from non-volatile memory.
     *
     * @param[in]  aChildRloc16   The child RLOC16 to remove.
     *
     * @retval  OT_ERROR_NONE        Successfully remove child.
     * @retval  OT_ERROR_NOT_FOUND   There is no specified child stored in non-volatile memory.
     *
     */
    otError RemoveStoredChild(uint16_t aChildRloc16);

    /**
     * This method store a child information into non-volatile memory.
     *
     * @param[in]  aChild          A reference to the child to store.
     *
     * @retval  OT_ERROR_NONE      Successfully store child.
     * @retval  OT_ERROR_NO_BUFS   Insufficient available buffers to store child.
     *
     */
    otError StoreChild(const Child &aChild);

    /**
     * This method returns a pointer to a Neighbor object.
     *
     * @param[in]  aAddress  The address of the Neighbor.
     *
     * @returns A pointer to the Neighbor corresponding to @p aAddress, NULL otherwise.
     *
     */
    Neighbor *GetNeighbor(uint16_t aAddress);

    /**
     * This method returns a pointer to a Neighbor object.
     *
     * @param[in]  aAddress  The address of the Neighbor.
     *
     * @returns A pointer to the Neighbor corresponding to @p aAddress, NULL otherwise.
     *
     */
    Neighbor *GetNeighbor(const Mac::ExtAddress &aAddress);

    /**
     * This method returns a pointer to a Neighbor object.
     *
     * @param[in]  aAddress  The address of the Neighbor.
     *
     * @returns A pointer to the Neighbor corresponding to @p aAddress, NULL otherwise.
     *
     */
    Neighbor *GetNeighbor(const Mac::Address &aAddress);

    /**
     * This method returns a pointer to a Neighbor object.
     *
     * @param[in]  aAddress  The address of the Neighbor.
     *
     * @returns A pointer to the Neighbor corresponding to @p aAddress, NULL otherwise.
     *
     */
    Neighbor *GetNeighbor(const Ip6::Address &aAddress);

    /**
     * This method returns a pointer to a Neighbor object if a one-way link is maintained
     * as in the instance of an FTD child with neighbor routers.
     *
     * @param[in]  aAddress  The address of the Neighbor.
     *
     * @returns A pointer to the Neighbor corresponding to @p aAddress, NULL otherwise.
     *
     */
    Neighbor *GetRxOnlyNeighborRouter(const Mac::Address &aAddress);

    /**
     * This method retains diagnostic information for an attached child by Child ID or RLOC16.
     *
     * @param[in]   aChildId    The Child ID or RLOC16 for an attached child.
     * @param[out]  aChildInfo  The child information.
     *
     */
    otError GetChildInfoById(uint16_t aChildId, otChildInfo &aChildInfo);

    /**
     * This method retains diagnostic information for an attached child by the internal table index.
     *
     * @param[in]   aChildIndex  The table index.
     * @param[out]  aChildInfo   The child information.
     *
     */
    otError GetChildInfoByIndex(uint16_t aChildIndex, otChildInfo &aChildInfo);

    /**
     * This methods gets the next IPv6 address (using an iterator) for a given child.
     *
     * @param[in]     aChildIndex  The child index.
     * @param[inout]  aIterator    A reference to iterator. On success the iterator will be updated to point to next
     *                             entry in the list.
     * @param[out]    aAddress     A reference to an IPv6 address where the child's next address is placed (on success).
     *
     * @retval OT_ERROR_NONE          Successfully found the next address (@p aAddress and @ aIterator are updated).
     * @retval OT_ERROR_NOT_FOUND     The child has no subsequent IPv6 address entry.
     * @retval OT_ERROR_INVALID_ARGS  Child at @p aChildIndex is not valid.
     *
     */
    otError GetChildNextIp6Address(uint16_t aChildIndex, Child::Ip6AddressIterator &aIterator, Ip6::Address &aAddress);

    /**
     * This method indicates whether or not the RLOC16 is an MTD child of this device.
     *
     * @param[in]  aRloc16  The RLOC16.
     *
     * @retval TRUE if @p aRloc16 is an MTD child of this device.
     * @retval FALSE if @p aRloc16 is not an MTD child of this device.
     *
     */
    bool IsMinimalChild(uint16_t aRloc16);

    /**
     * This method gets the next neighbor information. It is used to iterate through the entries of
     * the neighbor table.
     *
     * @param[inout]  aIterator  A reference to the iterator context. To get the first neighbor entry
                                 it should be set to OT_NEIGHBOR_INFO_ITERATOR_INIT.
     * @param[out]    aNeighInfo The neighbor information.
     *
     * @retval OT_ERROR_NONE          Successfully found the next neighbor entry in table.
     * @retval OT_ERROR_NOT_FOUND     No subsequent neighbor entry exists in the table.
     *
     */
    otError GetNextNeighborInfo(otNeighborInfoIterator &aIterator, otNeighborInfo &aNeighInfo);

    /**
     * This method indicates whether or not the given Thread partition attributes are preferred.
     *
     * @param[in]  aSingletonA   Whether or not the Thread Partition A has a single router.
     * @param[in]  aLeaderDataA  A reference to Thread Partition A's Leader Data.
     * @param[in]  aSingletonB   Whether or not the Thread Partition B has a single router.
     * @param[in]  aLeaderDataB  A reference to Thread Partition B's Leader Data.
     *
     * @retval 1   If partition A is preferred.
     * @retval 0   If partition A and B have equal preference.
     * @retval -1  If partition B is preferred.
     *
     */
    static int ComparePartitions(bool                 aSingletonA,
                                 const LeaderDataTlv &aLeaderDataA,
                                 bool                 aSingletonB,
                                 const LeaderDataTlv &aLeaderDataB);

    /**
     * This method checks if the destination is reachable.
     *
     * @param[in]  aMeshSource  The RLOC16 of the source.
     * @param[in]  aMeshDest    The RLOC16 of the destination.
     * @param[in]  aIp6Header   A reference to the IPv6 header of the message.
     *
     * @retval OT_ERROR_NONE  The destination is reachable.
     * @retval OT_ERROR_DROP  The destination is not reachable and the message should be dropped.
     *
     */
    otError CheckReachability(uint16_t aMeshSource, uint16_t aMeshDest, Ip6::Header &aIp6Header);

    /**
     * This method resolves 2-hop routing loops.
     *
     * @param[in]  aSourceMac   The RLOC16 of the previous hop.
     * @param[in]  aDestRloc16  The RLOC16 of the final destination.
     *
     */
    void ResolveRoutingLoops(uint16_t aSourceMac, uint16_t aDestRloc16);

    /**
     * This method checks if a given Router ID has correct value.
     *
     * @param[in]  aRouterId  The Router ID value.
     *
     * @retval TRUE   If @p aRouterId is in correct range [0..62].
     * @retval FALSE  If @p aRouterId is not a valid Router ID.
     *
     */
    static bool IsRouterIdValid(uint8_t aRouterId) { return aRouterId <= kMaxRouterId; }

    /**
     * This method fills an ConnectivityTlv.
     *
     * @param[out]  aTlv  A reference to the tlv to be filled.
     *
     */
    void FillConnectivityTlv(ConnectivityTlv &aTlv);

    /**
     * This method fills an RouteTlv.
     *
     * @param[out]  aTlv  A reference to the tlv to be filled.
     *
     */
    void FillRouteTlv(RouteTlv &aTlv);

    /**
     * This method generates an MLE Child Update Request message to be sent to the parent.
     *
     * @retval OT_ERROR_NONE     Successfully generated an MLE Child Update Request message.
     * @retval OT_ERROR_NO_BUFS  Insufficient buffers to generate the MLE Child Update Request message.
     *
     */
    otError SendChildUpdateRequest(void) { return Mle::SendChildUpdateRequest(); }

    otError SendLinkRequest(Neighbor *aNeighbor);

#if OPENTHREAD_CONFIG_MLE_STEERING_DATA_SET_OOB_ENABLE
    /**
     * This method sets steering data out of band
     *
     * @param[in]  aExtAddress  Value used to set steering data
     *                          All zeros clears steering data
     *                          All 0xFFs sets steering data to 0xFF
     *                          Anything else is used to compute the bloom filter
     *
     */
    void SetSteeringData(const Mac::ExtAddress *aExtAddress);
#endif // OPENTHREAD_CONFIG_MLE_STEERING_DATA_SET_OOB_ENABLE

    /**
     * This method gets the assigned parent priority.
     *
     * @returns The assigned parent priority value, -2 means not assigned.
     *
     */
    int8_t GetAssignParentPriority(void) const { return mParentPriority; }

    /**
     * This method sets the parent priority.
     *
     * @param[in]  aParentPriority  The parent priority value.
     *
     * @retval OT_ERROR_NONE           Successfully set the parent priority.
     * @retval OT_ERROR_INVALID_ARGS   If the parent priority value is not among 1, 0, -1 and -2.
     *
     */
    otError SetAssignParentPriority(int8_t aParentPriority);

    /**
     * This method gets the longest MLE Timeout TLV for all active MTD children.
     *
     * @param[out]  aTimeout  A reference to where the information is placed.
     *
     * @retval OT_ERROR_NONE           Successfully get the max child timeout
     * @retval OT_ERROR_INVALID_STATE  Not an active router
     * @retval OT_ERROR_NOT_FOUND      NO MTD child
     *
     */
    otError GetMaxChildTimeout(uint32_t &aTimeout) const;

    /**
     * This method register the "neighbor table changed" callback function.
     *
     * The provided callback (if non-NULL) will be invoked when a child/router entry is being added/remove to/from the
     * neighbor table. Subsequent calls to this method will overwrite the previous callback.
     *
     * @param[in] aCallback    A pointer to callback handler function.
     *
     */
    void RegisterNeighborTableChangedCallback(otNeighborTableCallback aCallback)
    {
        mNeighborTableChangedCallback = aCallback;
    }

    /**
     * This method signals a "neighbor table changed" events (invoking the registered callback function).
     *
     * @param[in] aEvent     The event to emit (child/router added/removed).
     * @param[in] aNeighbor  The neighbor that is being added/removed.
     *
     */
    void Signal(otNeighborTableEvent aEvent, Neighbor &aNeighbor);

    /**
     * This method returns whether the device has any sleepy children subscribed the address.
     *
     * @param[in]  aAddress  The reference of the address.
     *
     * @retval TRUE   If the device has any sleepy children subscribed the address @p aAddress.
     * @retval FALSE  If the device doesn't have any sleepy children subscribed the address @p aAddress.
     *
     */
    bool HasSleepyChildrenSubscribed(const Ip6::Address &aAddress);

    /**
     * This method returns whether the specific child subscribed the address.
     *
     * @param[in]  aAddress  The reference of the address.
     * @param[in]  aChild    The reference of the child.
     *
     * @retval TRUE   If the sleepy child @p aChild subscribed the address @p aAddress.
     * @retval FALSE  If the sleepy child @p aChild did not subscribe the address @p aAddress.
     *
     */
    bool IsSleepyChildSubscribed(const Ip6::Address &aAddress, Child &aChild);

    /**
     * This method resets the MLE Advertisement Trickle timer interval.
     *
     */
    void ResetAdvertiseInterval(void);

    /**
     * This static method converts link quality to route cost.
     *
     * @param[in]  aLinkQuality  The link quality.
     *
     * @returns The link cost corresponding to @p aLinkQuality.
     *
     */
    static uint8_t LinkQualityToCost(uint8_t aLinkQuality);

#if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
    /**
     * This method generates an MLE Time Synchronization message.
     *
     * @retval OT_ERROR_NONE     Successfully sent an MLE Time Synchronization message.
     * @retval OT_ERROR_NO_BUFS  Insufficient buffers to generate the MLE Time Synchronization message.
     *
     */
    otError SendTimeSync(void);
#endif

private:
    enum
    {
        kDiscoveryMaxJitter = 250u,  ///< Maximum jitter time used to delay Discovery Responses in milliseconds.
        kStateUpdatePeriod  = 1000u, ///< State update period in milliseconds.
        kUnsolicitedDataResponseJitter = 500u, ///< Maximum delay before unsolicited Data Response in milliseconds.
    };

    otError AppendConnectivity(Message &aMessage);
    otError AppendChildAddresses(Message &aMessage, Child &aChild);
    otError AppendRoute(Message &aMessage);
    otError AppendActiveDataset(Message &aMessage);
    otError AppendPendingDataset(Message &aMessage);
    otError GetChildInfo(Child &aChild, otChildInfo &aChildInfo);
    void    GetNeighborInfo(Neighbor &aNeighbor, otNeighborInfo &aNeighInfo);
    otError RefreshStoredChildren(void);
    void    HandleDetachStart(void);
    otError HandleChildStart(AttachMode aMode);
    otError HandleLinkRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo, Neighbor *aNeighbor);
    otError HandleLinkAccept(const Message &         aMessage,
                             const Ip6::MessageInfo &aMessageInfo,
                             uint32_t                aKeySequence,
                             Neighbor *              aNeighbor);
    otError HandleLinkAccept(const Message &         aMessage,
                             const Ip6::MessageInfo &aMessageInfo,
                             uint32_t                aKeySequence,
                             Neighbor *              aNeighbor,
                             bool                    aRequest);
    otError HandleLinkAcceptAndRequest(const Message &         aMessage,
                                       const Ip6::MessageInfo &aMessageInfo,
                                       uint32_t                aKeySequence,
                                       Neighbor *              aNeighbor);
    otError HandleAdvertisement(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo, Neighbor *);
    otError HandleParentRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
    otError HandleChildIdRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo, uint32_t aKeySequence);
    otError HandleChildUpdateRequest(const Message &         aMessage,
                                     const Ip6::MessageInfo &aMessageInfo,
                                     uint32_t                aKeySequence);
    otError HandleChildUpdateResponse(const Message &         aMessage,
                                      const Ip6::MessageInfo &aMessageInfo,
                                      uint32_t                aKeySequence,
                                      Neighbor *              aNeighbor);
    otError HandleDataRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo, const Neighbor *aNeighbor);
    void    HandleNetworkDataUpdateRouter(void);
    otError HandleDiscoveryRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
#if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
    void HandleTimeSync(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo, const Neighbor *aNeighbor);
#endif

    otError ProcessRouteTlv(const RouteTlv &aRoute);
    void    StopAdvertiseTimer(void);
    otError SendAddressSolicit(ThreadStatusTlv::Status aStatus);
    otError SendAddressRelease(void);
    void    SendAddressSolicitResponse(const Coap::Message &   aRequest,
                                       const Router *          aRouter,
                                       const Ip6::MessageInfo &aMessageInfo);
    otError SendAdvertisement(void);
    otError SendLinkAccept(const Ip6::MessageInfo &aMessageInfo,
                           Neighbor *              aNeighbor,
                           const TlvRequestTlv &   aTlvRequest,
                           const ChallengeTlv &    aChallenge);
    void    SendParentResponse(Child *aChild, const ChallengeTlv &aChallenge, bool aRoutersOnlyRequest);
    otError SendChildIdResponse(Child &aChild);
    otError SendChildUpdateRequest(Child &aChild);
    void    SendChildUpdateResponse(Child *                 aChild,
                                    const Ip6::MessageInfo &aMessageInfo,
                                    const uint8_t *         aTlvs,
                                    uint8_t                 aTlvsLength,
                                    const ChallengeTlv &    aChallenge);
    otError SendDataResponse(const Ip6::Address &aDestination,
                             const uint8_t *     aTlvs,
                             uint8_t             aTlvsLength,
                             uint16_t            aDelay);
    otError SendDiscoveryResponse(const Ip6::Address &aDestination, uint16_t aPanId);

    void    SetStateRouter(uint16_t aRloc16);
    void    SetStateLeader(uint16_t aRloc16);
    void    StopLeader(void);
    void    SynchronizeChildNetworkData(void);
    otError UpdateChildAddresses(const Message &aMessage, uint16_t aOffset, Child &aChild);
    void    UpdateRoutes(const RouteTlv &aRoute, uint8_t aRouterId);
    bool    UpdateLinkQualityOut(const RouteTlv &aRoute, Router &aNeighbor, bool &aResetAdvInterval);

    static void HandleAddressSolicitResponse(void *               aContext,
                                             otMessage *          aMessage,
                                             const otMessageInfo *aMessageInfo,
                                             otError              aResult);
    void HandleAddressSolicitResponse(Coap::Message *aMessage, const Ip6::MessageInfo *aMessageInfo, otError aResult);
    static void HandleAddressRelease(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo);
    void        HandleAddressRelease(Coap::Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
    static void HandleAddressSolicit(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo);
    void        HandleAddressSolicit(Coap::Message &aMessage, const Ip6::MessageInfo &aMessageInfo);

    static bool IsSingleton(const RouteTlv &aRouteTlv);

    void HandlePartitionChange(void);

    void SetChildStateToValid(Child &aChild);
    bool HasChildren(void);
    void RemoveChildren(void);
    bool HasMinDowngradeNeighborRouters(void);
    bool HasOneNeighborWithComparableConnectivity(const RouteTlv &aRoute, uint8_t aRouterId);
    bool HasSmallNumberOfChildren(void);

    static bool HandleAdvertiseTimer(TrickleTimer &aTimer);
    bool        HandleAdvertiseTimer(void);
    static void HandleStateUpdateTimer(Timer &aTimer);
    void        HandleStateUpdateTimer(void);

    TrickleTimer mAdvertiseTimer;
    TimerMilli   mStateUpdateTimer;

    Coap::Resource mAddressSolicit;
    Coap::Resource mAddressRelease;

    ChildTable  mChildTable;
    RouterTable mRouterTable;

    otNeighborTableCallback mNeighborTableChangedCallback;

    uint8_t  mChallengeTimeout;
    uint8_t  mChallenge[8];
    uint16_t mNextChildId;
    uint8_t  mNetworkIdTimeout;
    uint8_t  mRouterUpgradeThreshold;
    uint8_t  mRouterDowngradeThreshold;
    uint8_t  mLeaderWeight;
    uint32_t mFixedLeaderPartitionId; ///< only for certification testing
    bool     mRouterEligible : 1;
    bool     mAddressSolicitPending : 1;

    uint8_t mRouterId;
    uint8_t mPreviousRouterId;

    uint32_t mPreviousPartitionIdRouter;         ///< The partition ID when last operating as a router
    uint32_t mPreviousPartitionId;               ///< The partition ID when last attached
    uint8_t  mPreviousPartitionRouterIdSequence; ///< The router ID sequence when last attached
    uint8_t  mPreviousPartitionIdTimeout;        ///< The partition ID timeout when last attached

    uint8_t mRouterSelectionJitter;        ///< The variable to save the assigned jitter value.
    uint8_t mRouterSelectionJitterTimeout; ///< The Timeout prior to request/release Router ID.

    int8_t mParentPriority; ///< The assigned parent priority value, -2 means not assigned.

#if OPENTHREAD_CONFIG_MLE_STEERING_DATA_SET_OOB_ENABLE
    MeshCoP::SteeringDataTlv mSteeringData;
#endif // OPENTHREAD_CONFIG_MLE_STEERING_DATA_SET_OOB_ENABLE
};

} // namespace Mle

/**
 * @}
 */

} // namespace ot

#endif // MLE_ROUTER_FTD_HPP_