src/core/backbone_router/bbr_local.cpp - third_party/openthread - Git at Google

 /*
  *  Copyright (c) 2019, 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 implements local Backbone Router service.
  */

 #include "bbr_local.hpp"

 #if OPENTHREAD_FTD && OPENTHREAD_CONFIG_BACKBONE_ROUTER_ENABLE

 #include "common/code_utils.hpp"
 #include "common/instance.hpp"
 #include "common/locator_getters.hpp"
 #include "common/logging.hpp"
 #include "common/random.hpp"
 #include "thread/mle_types.hpp"
 #include "thread/thread_netif.hpp"

 namespace ot {

 namespace BackboneRouter {

 Local::Local(Instance &aInstance)
     : InstanceLocator(aInstance)
     , mState(OT_BACKBONE_ROUTER_STATE_DISABLED)
     , mMlrTimeout(Mle::kMlrTimeoutDefault)
     , mReregistrationDelay(Mle::kRegistrationDelayDefault)
     , mSequenceNumber(Random::NonCrypto::GetUint8() % 127)
     , mRegistrationJitter(Mle::kBackboneRouterRegistrationJitter)
     , mIsServiceAdded(false)
     , mDomainPrefixCallback(nullptr)
     , mDomainPrefixCallbackContext(nullptr)
 #if OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE
     , mSkipSeqNumIncrease(false)
 #endif
 {
     mDomainPrefixConfig.GetPrefix().SetLength(0);

     // Primary Backbone Router Aloc
     mBackboneRouterPrimaryAloc.InitAsThreadOriginRealmLocalScope();
     mBackboneRouterPrimaryAloc.GetAddress().GetIid().SetToLocator(Mle::kAloc16BackboneRouterPrimary);

     // All Network Backbone Routers Multicast Address.
     mAllNetworkBackboneRouters.Clear();

     mAllNetworkBackboneRouters.mFields.m8[0]  = 0xff; // Multicast
     mAllNetworkBackboneRouters.mFields.m8[1]  = 0x32; // Flags = 3, Scope = 2
     mAllNetworkBackboneRouters.mFields.m8[15] = 3;    // Group ID = 3

     // All Domain Backbone Routers Multicast Address.
     mAllDomainBackboneRouters.Clear();

     mAllDomainBackboneRouters.mFields.m8[0]  = 0xff; // Multicast
     mAllDomainBackboneRouters.mFields.m8[1]  = 0x32; // Flags = 3, Scope = 2
     mAllDomainBackboneRouters.mFields.m8[15] = 3;    // Group ID = 3
 }

 void Local::SetEnabled(bool aEnable)
 {
     VerifyOrExit(aEnable == (mState == OT_BACKBONE_ROUTER_STATE_DISABLED));

     if (aEnable)
     {
         SetState(OT_BACKBONE_ROUTER_STATE_SECONDARY);
         AddDomainPrefixToNetworkData();
         IgnoreError(AddService());
     }
     else
     {
         RemoveDomainPrefixFromNetworkData();
         RemoveService();
         SetState(OT_BACKBONE_ROUTER_STATE_DISABLED);
     }

 exit:
     return;
 }

 void Local::Reset(void)
 {
     VerifyOrExit(mState != OT_BACKBONE_ROUTER_STATE_DISABLED);

     RemoveService();

     if (mState == OT_BACKBONE_ROUTER_STATE_PRIMARY)
     {
         // Increase sequence number when changing from Primary to Secondary.
         SequenceNumberIncrease();
         Get<Notifier>().Signal(kEventThreadBackboneRouterLocalChanged);
         SetState(OT_BACKBONE_ROUTER_STATE_SECONDARY);
     }

 exit:
     return;
 }

 void Local::GetConfig(BackboneRouterConfig &aConfig) const
 {
     aConfig.mSequenceNumber      = mSequenceNumber;
     aConfig.mReregistrationDelay = mReregistrationDelay;
     aConfig.mMlrTimeout          = mMlrTimeout;
 }

 Error Local::SetConfig(const BackboneRouterConfig &aConfig)
 {
     Error error  = kErrorNone;
     bool  update = false;

 #if !OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE
     VerifyOrExit(aConfig.mMlrTimeout >= Mle::kMlrTimeoutMin && aConfig.mMlrTimeout <= Mle::kMlrTimeoutMax,
                  error = kErrorInvalidArgs);
 #endif
     // Validate configuration according to Thread 1.2.1 Specification 5.21.3.3:
     // "The Reregistration Delay in seconds MUST be lower than (0.5 * MLR Timeout). It MUST be at least 1."
     VerifyOrExit(aConfig.mReregistrationDelay >= 1, error = kErrorInvalidArgs);
     static_assert(sizeof(aConfig.mReregistrationDelay) < sizeof(aConfig.mMlrTimeout),
                   "the calculation below might overflow");
     VerifyOrExit(aConfig.mReregistrationDelay * 2 < aConfig.mMlrTimeout, error = kErrorInvalidArgs);

     if (aConfig.mReregistrationDelay != mReregistrationDelay)
     {
         mReregistrationDelay = aConfig.mReregistrationDelay;
         update               = true;
     }

     if (aConfig.mMlrTimeout != mMlrTimeout)
     {
         mMlrTimeout = aConfig.mMlrTimeout;
         update      = true;
     }

     if (aConfig.mSequenceNumber != mSequenceNumber)
     {
         mSequenceNumber = aConfig.mSequenceNumber;
         update          = true;
     }

     if (update)
     {
         Get<Notifier>().Signal(kEventThreadBackboneRouterLocalChanged);

         IgnoreError(AddService());
     }

 exit:
     LogBackboneRouterService("Set", error);
     return error;
 }

 Error Local::AddService(bool aForce)
 {
     Error                                            error = kErrorInvalidState;
     NetworkData::Service::BackboneRouter::ServerData serverData;

     VerifyOrExit(mState != OT_BACKBONE_ROUTER_STATE_DISABLED && Get<Mle::Mle>().IsAttached());

     VerifyOrExit(aForce /* if register by force */ ||
                  !Get<BackboneRouter::Leader>().HasPrimary() /* if no available Backbone Router service */ ||
                  Get<BackboneRouter::Leader>().GetServer16() == Get<Mle::MleRouter>().GetRloc16()
                  /* If the device itself should be BBR. */
     );

     serverData.SetSequenceNumber(mSequenceNumber);
     serverData.SetReregistrationDelay(mReregistrationDelay);
     serverData.SetMlrTimeout(mMlrTimeout);

     SuccessOrExit(error = Get<NetworkData::Service::Manager>().Add<NetworkData::Service::BackboneRouter>(serverData));
     Get<NetworkData::Notifier>().HandleServerDataUpdated();

     mIsServiceAdded = true;

 exit:
     LogBackboneRouterService("Add", error);
     return error;
 }

 void Local::RemoveService(void)
 {
     Error error;

     SuccessOrExit(error = Get<NetworkData::Service::Manager>().Remove<NetworkData::Service::BackboneRouter>());
     Get<NetworkData::Notifier>().HandleServerDataUpdated();
     mIsServiceAdded = false;

 exit:
     LogBackboneRouterService("Remove", error);
 }

 void Local::SetState(BackboneRouterState aState)
 {
     VerifyOrExit(mState != aState);

     if (mState == OT_BACKBONE_ROUTER_STATE_DISABLED)
     {
         // Update All Network Backbone Routers Multicast Address for both Secondary and Primary state.
         mAllNetworkBackboneRouters.SetMulticastNetworkPrefix(Get<Mle::MleRouter>().GetMeshLocalPrefix());
     }

     if (mState == OT_BACKBONE_ROUTER_STATE_PRIMARY)
     {
         Get<ThreadNetif>().RemoveUnicastAddress(mBackboneRouterPrimaryAloc);
     }
     else if (aState == OT_BACKBONE_ROUTER_STATE_PRIMARY)
     {
         // Add Primary Backbone Router Aloc for Primary Backbone Router.
         mBackboneRouterPrimaryAloc.GetAddress().SetPrefix(Get<Mle::MleRouter>().GetMeshLocalPrefix());
         Get<ThreadNetif>().AddUnicastAddress(mBackboneRouterPrimaryAloc);
     }

     mState = aState;

     Get<Notifier>().Signal(kEventThreadBackboneRouterStateChanged);

 exit:
     return;
 }

 void Local::HandleBackboneRouterPrimaryUpdate(Leader::State aState, const BackboneRouterConfig &aConfig)
 {
     OT_UNUSED_VARIABLE(aState);

     VerifyOrExit(mState != OT_BACKBONE_ROUTER_STATE_DISABLED && Get<Mle::MleRouter>().IsAttached());

     // Wait some jitter before trying to Register.
     if (aConfig.mServer16 == Mac::kShortAddrInvalid)
     {
         uint8_t delay = 1;

         if (!Get<Mle::MleRouter>().IsLeader())
         {
             delay += Random::NonCrypto::GetUint8InRange(0, mRegistrationJitter < 255 ? mRegistrationJitter + 1
                                                                                      : mRegistrationJitter);
         }

         // Here uses the timer resource in Mle.
         Get<Mle::MleRouter>().SetBackboneRouterRegistrationDelay(delay);
     }
     else if (aConfig.mServer16 != Get<Mle::MleRouter>().GetRloc16())
     {
         Reset();
     }
     else if (!mIsServiceAdded)
     {
         // Here original PBBR restores its Backbone Router Service from Thread Network,
         // Intentionally skips the state update as PBBR will refresh its service.
         mSequenceNumber      = aConfig.mSequenceNumber;
         mReregistrationDelay = aConfig.mReregistrationDelay;
         mMlrTimeout          = aConfig.mMlrTimeout;

 #if OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE
         if (mSkipSeqNumIncrease)
         {
             // BBR-TC-02 forces Sequence Number for the reference device with raw UDP API
             // Do not increase Sequence Number in that case.
         }
         else
 #endif
         {
             SequenceNumberIncrease();
         }

         Get<Notifier>().Signal(kEventThreadBackboneRouterLocalChanged);
         if (AddService(true /* Force registration to refresh and restore Primary state */) == kErrorNone)
         {
             Get<NetworkData::Notifier>().HandleServerDataUpdated();
         }
     }
     else
     {
         SetState(OT_BACKBONE_ROUTER_STATE_PRIMARY);
     }

 exit:
     return;
 }

 Error Local::GetDomainPrefix(NetworkData::OnMeshPrefixConfig &aConfig)
 {
     Error error = kErrorNone;

     VerifyOrExit(mDomainPrefixConfig.GetPrefix().GetLength() > 0, error = kErrorNotFound);

     aConfig = mDomainPrefixConfig;

 exit:
     return error;
 }

 Error Local::RemoveDomainPrefix(const Ip6::Prefix &aPrefix)
 {
     Error error = kErrorNone;

     VerifyOrExit(aPrefix.GetLength() > 0, error = kErrorInvalidArgs);
     VerifyOrExit(mDomainPrefixConfig.GetPrefix() == aPrefix, error = kErrorNotFound);

     if (IsEnabled())
     {
         RemoveDomainPrefixFromNetworkData();
     }

     mDomainPrefixConfig.GetPrefix().SetLength(0);

 exit:
     return error;
 }

 Error Local::SetDomainPrefix(const NetworkData::OnMeshPrefixConfig &aConfig)
 {
     Error error = kErrorNone;

     VerifyOrExit(aConfig.IsValid(GetInstance()), error = kErrorInvalidArgs);

     if (IsEnabled())
     {
         RemoveDomainPrefixFromNetworkData();
     }

     mDomainPrefixConfig = aConfig;
     LogDomainPrefix("Set", kErrorNone);

     if (IsEnabled())
     {
         AddDomainPrefixToNetworkData();
     }

 exit:
     return error;
 }

 void Local::ApplyMeshLocalPrefix(void)
 {
     VerifyOrExit(IsEnabled());

     Get<BackboneTmfAgent>().UnsubscribeMulticast(mAllNetworkBackboneRouters);
     mAllNetworkBackboneRouters.SetMulticastNetworkPrefix(Get<Mle::MleRouter>().GetMeshLocalPrefix());
     Get<BackboneTmfAgent>().SubscribeMulticast(mAllNetworkBackboneRouters);

     if (IsPrimary())
     {
         Get<ThreadNetif>().RemoveUnicastAddress(mBackboneRouterPrimaryAloc);
         mBackboneRouterPrimaryAloc.GetAddress().SetPrefix(Get<Mle::MleRouter>().GetMeshLocalPrefix());
         Get<ThreadNetif>().AddUnicastAddress(mBackboneRouterPrimaryAloc);
     }

 exit:
     return;
 }

 void Local::HandleDomainPrefixUpdate(Leader::DomainPrefixState aState)
 {
     if (!IsEnabled())
     {
         ExitNow();
     }

     if (aState == Leader::kDomainPrefixRemoved || aState == Leader::kDomainPrefixRefreshed)
     {
         Get<BackboneTmfAgent>().UnsubscribeMulticast(mAllDomainBackboneRouters);
     }

     if (aState == Leader::kDomainPrefixAdded || aState == Leader::kDomainPrefixRefreshed)
     {
         mAllDomainBackboneRouters.SetMulticastNetworkPrefix(*Get<Leader>().GetDomainPrefix());
         Get<BackboneTmfAgent>().SubscribeMulticast(mAllDomainBackboneRouters);
     }

     if (mDomainPrefixCallback != nullptr)
     {
         switch (aState)
         {
         case Leader::kDomainPrefixAdded:
             mDomainPrefixCallback(mDomainPrefixCallbackContext, OT_BACKBONE_ROUTER_DOMAIN_PREFIX_ADDED,
                                   Get<Leader>().GetDomainPrefix());
             break;
         case Leader::kDomainPrefixRemoved:
             mDomainPrefixCallback(mDomainPrefixCallbackContext, OT_BACKBONE_ROUTER_DOMAIN_PREFIX_REMOVED,
                                   Get<Leader>().GetDomainPrefix());
             break;
         case Leader::kDomainPrefixRefreshed:
             mDomainPrefixCallback(mDomainPrefixCallbackContext, OT_BACKBONE_ROUTER_DOMAIN_PREFIX_CHANGED,
                                   Get<Leader>().GetDomainPrefix());
             break;
         default:
             break;
         }
     }

 exit:
     return;
 }

 void Local::RemoveDomainPrefixFromNetworkData(void)
 {
     Error error = kErrorNotFound; // only used for logging.

     if (mDomainPrefixConfig.mPrefix.mLength > 0)
     {
         error = Get<NetworkData::Local>().RemoveOnMeshPrefix(mDomainPrefixConfig.GetPrefix());
     }

     LogDomainPrefix("Remove", error);
 }

 void Local::SequenceNumberIncrease(void)
 {
     switch (mSequenceNumber)
     {
     case 126:
     case 127:
         mSequenceNumber = 0;
         break;
     case 254:
     case 255:
         mSequenceNumber = 128;
         break;
     default:
         mSequenceNumber++;
         break;
     }
 }

 void Local::AddDomainPrefixToNetworkData(void)
 {
     Error error = kErrorNotFound; // only used for logging.

     if (mDomainPrefixConfig.GetPrefix().GetLength() > 0)
     {
         error = Get<NetworkData::Local>().AddOnMeshPrefix(mDomainPrefixConfig);
     }

     LogDomainPrefix("Add", error);
 }

 #if (OPENTHREAD_CONFIG_LOG_LEVEL >= OT_LOG_LEVEL_INFO) && (OPENTHREAD_CONFIG_LOG_BBR == 1)
 void Local::LogDomainPrefix(const char *aAction, Error aError)
 {
     otLogInfoBbr("%s Domain Prefix: %s, %s", aAction, mDomainPrefixConfig.GetPrefix().ToString().AsCString(),
                  ErrorToString(aError));
 }

 void Local::LogBackboneRouterService(const char *aAction, Error aError)
 {
     otLogInfoBbr("%s BBR Service: seqno (%d), delay (%ds), timeout (%ds), %s", aAction, mSequenceNumber,
                  mReregistrationDelay, mMlrTimeout, ErrorToString(aError));
 }
 #endif

 void Local::SetDomainPrefixCallback(otBackboneRouterDomainPrefixCallback aCallback, void *aContext)
 {
     mDomainPrefixCallback        = aCallback;
     mDomainPrefixCallbackContext = aContext;
 }

 #if OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE
 void Local::ConfigSkipSeqNumIncrease(bool aSkip)
 {
     mSkipSeqNumIncrease = aSkip;
 }
 #endif

 } // namespace BackboneRouter

 } // namespace ot

 #endif // OPENTHREAD_FTD && OPENTHREAD_CONFIG_BACKBONE_ROUTER_ENABLE
	/*
	* Copyright (c) 2019, 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 implements local Backbone Router service.
	*/

	#include "bbr_local.hpp"

	#if OPENTHREAD_FTD && OPENTHREAD_CONFIG_BACKBONE_ROUTER_ENABLE

	#include "common/code_utils.hpp"
	#include "common/instance.hpp"
	#include "common/locator_getters.hpp"
	#include "common/logging.hpp"
	#include "common/random.hpp"
	#include "thread/mle_types.hpp"
	#include "thread/thread_netif.hpp"

	namespace ot {

	namespace BackboneRouter {

	Local::Local(Instance &aInstance)
	: InstanceLocator(aInstance)
	, mState(OT_BACKBONE_ROUTER_STATE_DISABLED)
	, mMlrTimeout(Mle::kMlrTimeoutDefault)
	, mReregistrationDelay(Mle::kRegistrationDelayDefault)
	, mSequenceNumber(Random::NonCrypto::GetUint8() % 127)
	, mRegistrationJitter(Mle::kBackboneRouterRegistrationJitter)
	, mIsServiceAdded(false)
	, mDomainPrefixCallback(nullptr)
	, mDomainPrefixCallbackContext(nullptr)
	#if OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE
	, mSkipSeqNumIncrease(false)
	#endif
	{
	mDomainPrefixConfig.GetPrefix().SetLength(0);

	// Primary Backbone Router Aloc
	mBackboneRouterPrimaryAloc.InitAsThreadOriginRealmLocalScope();
	mBackboneRouterPrimaryAloc.GetAddress().GetIid().SetToLocator(Mle::kAloc16BackboneRouterPrimary);

	// All Network Backbone Routers Multicast Address.
	mAllNetworkBackboneRouters.Clear();

	mAllNetworkBackboneRouters.mFields.m8[0] = 0xff; // Multicast
	mAllNetworkBackboneRouters.mFields.m8[1] = 0x32; // Flags = 3, Scope = 2
	mAllNetworkBackboneRouters.mFields.m8[15] = 3; // Group ID = 3

	// All Domain Backbone Routers Multicast Address.
	mAllDomainBackboneRouters.Clear();

	mAllDomainBackboneRouters.mFields.m8[0] = 0xff; // Multicast
	mAllDomainBackboneRouters.mFields.m8[1] = 0x32; // Flags = 3, Scope = 2
	mAllDomainBackboneRouters.mFields.m8[15] = 3; // Group ID = 3
	}

	void Local::SetEnabled(bool aEnable)
	{
	VerifyOrExit(aEnable == (mState == OT_BACKBONE_ROUTER_STATE_DISABLED));

	if (aEnable)
	{
	SetState(OT_BACKBONE_ROUTER_STATE_SECONDARY);
	AddDomainPrefixToNetworkData();
	IgnoreError(AddService());
	}
	else
	{
	RemoveDomainPrefixFromNetworkData();
	RemoveService();
	SetState(OT_BACKBONE_ROUTER_STATE_DISABLED);
	}

	exit:
	return;
	}

	void Local::Reset(void)
	{
	VerifyOrExit(mState != OT_BACKBONE_ROUTER_STATE_DISABLED);

	RemoveService();

	if (mState == OT_BACKBONE_ROUTER_STATE_PRIMARY)
	{
	// Increase sequence number when changing from Primary to Secondary.
	SequenceNumberIncrease();
	Get<Notifier>().Signal(kEventThreadBackboneRouterLocalChanged);
	SetState(OT_BACKBONE_ROUTER_STATE_SECONDARY);
	}

	exit:
	return;
	}

	void Local::GetConfig(BackboneRouterConfig &aConfig) const
	{
	aConfig.mSequenceNumber = mSequenceNumber;
	aConfig.mReregistrationDelay = mReregistrationDelay;
	aConfig.mMlrTimeout = mMlrTimeout;
	}

	Error Local::SetConfig(const BackboneRouterConfig &aConfig)
	{
	Error error = kErrorNone;
	bool update = false;

	#if !OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE
	VerifyOrExit(aConfig.mMlrTimeout >= Mle::kMlrTimeoutMin && aConfig.mMlrTimeout <= Mle::kMlrTimeoutMax,
	error = kErrorInvalidArgs);
	#endif
	// Validate configuration according to Thread 1.2.1 Specification 5.21.3.3:
	// "The Reregistration Delay in seconds MUST be lower than (0.5 * MLR Timeout). It MUST be at least 1."
	VerifyOrExit(aConfig.mReregistrationDelay >= 1, error = kErrorInvalidArgs);
	static_assert(sizeof(aConfig.mReregistrationDelay) < sizeof(aConfig.mMlrTimeout),
	"the calculation below might overflow");
	VerifyOrExit(aConfig.mReregistrationDelay * 2 < aConfig.mMlrTimeout, error = kErrorInvalidArgs);

	if (aConfig.mReregistrationDelay != mReregistrationDelay)
	{
	mReregistrationDelay = aConfig.mReregistrationDelay;
	update = true;
	}

	if (aConfig.mMlrTimeout != mMlrTimeout)
	{
	mMlrTimeout = aConfig.mMlrTimeout;
	update = true;
	}

	if (aConfig.mSequenceNumber != mSequenceNumber)
	{
	mSequenceNumber = aConfig.mSequenceNumber;
	update = true;
	}

	if (update)
	{
	Get<Notifier>().Signal(kEventThreadBackboneRouterLocalChanged);

	IgnoreError(AddService());
	}

	exit:
	LogBackboneRouterService("Set", error);
	return error;
	}

	Error Local::AddService(bool aForce)
	{
	Error error = kErrorInvalidState;
	NetworkData::Service::BackboneRouter::ServerData serverData;

	VerifyOrExit(mState != OT_BACKBONE_ROUTER_STATE_DISABLED && Get<Mle::Mle>().IsAttached());

	VerifyOrExit(aForce /* if register by force */ \|\|
	!Get<BackboneRouter::Leader>().HasPrimary() /* if no available Backbone Router service */ \|\|
	Get<BackboneRouter::Leader>().GetServer16() == Get<Mle::MleRouter>().GetRloc16()
	/* If the device itself should be BBR. */
	);

	serverData.SetSequenceNumber(mSequenceNumber);
	serverData.SetReregistrationDelay(mReregistrationDelay);
	serverData.SetMlrTimeout(mMlrTimeout);

	SuccessOrExit(error = Get<NetworkData::Service::Manager>().Add<NetworkData::Service::BackboneRouter>(serverData));
	Get<NetworkData::Notifier>().HandleServerDataUpdated();

	mIsServiceAdded = true;

	exit:
	LogBackboneRouterService("Add", error);
	return error;
	}

	void Local::RemoveService(void)
	{
	Error error;

	SuccessOrExit(error = Get<NetworkData::Service::Manager>().Remove<NetworkData::Service::BackboneRouter>());
	Get<NetworkData::Notifier>().HandleServerDataUpdated();
	mIsServiceAdded = false;

	exit:
	LogBackboneRouterService("Remove", error);
	}

	void Local::SetState(BackboneRouterState aState)
	{
	VerifyOrExit(mState != aState);

	if (mState == OT_BACKBONE_ROUTER_STATE_DISABLED)
	{
	// Update All Network Backbone Routers Multicast Address for both Secondary and Primary state.
	mAllNetworkBackboneRouters.SetMulticastNetworkPrefix(Get<Mle::MleRouter>().GetMeshLocalPrefix());
	}

	if (mState == OT_BACKBONE_ROUTER_STATE_PRIMARY)
	{
	Get<ThreadNetif>().RemoveUnicastAddress(mBackboneRouterPrimaryAloc);
	}
	else if (aState == OT_BACKBONE_ROUTER_STATE_PRIMARY)
	{
	// Add Primary Backbone Router Aloc for Primary Backbone Router.
	mBackboneRouterPrimaryAloc.GetAddress().SetPrefix(Get<Mle::MleRouter>().GetMeshLocalPrefix());
	Get<ThreadNetif>().AddUnicastAddress(mBackboneRouterPrimaryAloc);
	}

	mState = aState;

	Get<Notifier>().Signal(kEventThreadBackboneRouterStateChanged);

	exit:
	return;
	}

	void Local::HandleBackboneRouterPrimaryUpdate(Leader::State aState, const BackboneRouterConfig &aConfig)
	{
	OT_UNUSED_VARIABLE(aState);

	VerifyOrExit(mState != OT_BACKBONE_ROUTER_STATE_DISABLED && Get<Mle::MleRouter>().IsAttached());

	// Wait some jitter before trying to Register.
	if (aConfig.mServer16 == Mac::kShortAddrInvalid)
	{
	uint8_t delay = 1;

	if (!Get<Mle::MleRouter>().IsLeader())
	{
	delay += Random::NonCrypto::GetUint8InRange(0, mRegistrationJitter < 255 ? mRegistrationJitter + 1
	: mRegistrationJitter);
	}

	// Here uses the timer resource in Mle.
	Get<Mle::MleRouter>().SetBackboneRouterRegistrationDelay(delay);
	}
	else if (aConfig.mServer16 != Get<Mle::MleRouter>().GetRloc16())
	{
	Reset();
	}
	else if (!mIsServiceAdded)
	{
	// Here original PBBR restores its Backbone Router Service from Thread Network,
	// Intentionally skips the state update as PBBR will refresh its service.
	mSequenceNumber = aConfig.mSequenceNumber;
	mReregistrationDelay = aConfig.mReregistrationDelay;
	mMlrTimeout = aConfig.mMlrTimeout;

	#if OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE
	if (mSkipSeqNumIncrease)
	{
	// BBR-TC-02 forces Sequence Number for the reference device with raw UDP API
	// Do not increase Sequence Number in that case.
	}
	else
	#endif
	{
	SequenceNumberIncrease();
	}

	Get<Notifier>().Signal(kEventThreadBackboneRouterLocalChanged);
	if (AddService(true /* Force registration to refresh and restore Primary state */) == kErrorNone)
	{
	Get<NetworkData::Notifier>().HandleServerDataUpdated();
	}
	}
	else
	{
	SetState(OT_BACKBONE_ROUTER_STATE_PRIMARY);
	}

	exit:
	return;
	}

	Error Local::GetDomainPrefix(NetworkData::OnMeshPrefixConfig &aConfig)
	{
	Error error = kErrorNone;

	VerifyOrExit(mDomainPrefixConfig.GetPrefix().GetLength() > 0, error = kErrorNotFound);

	aConfig = mDomainPrefixConfig;

	exit:
	return error;
	}

	Error Local::RemoveDomainPrefix(const Ip6::Prefix &aPrefix)
	{
	Error error = kErrorNone;

	VerifyOrExit(aPrefix.GetLength() > 0, error = kErrorInvalidArgs);
	VerifyOrExit(mDomainPrefixConfig.GetPrefix() == aPrefix, error = kErrorNotFound);

	if (IsEnabled())
	{
	RemoveDomainPrefixFromNetworkData();
	}

	mDomainPrefixConfig.GetPrefix().SetLength(0);

	exit:
	return error;
	}

	Error Local::SetDomainPrefix(const NetworkData::OnMeshPrefixConfig &aConfig)
	{
	Error error = kErrorNone;

	VerifyOrExit(aConfig.IsValid(GetInstance()), error = kErrorInvalidArgs);

	if (IsEnabled())
	{
	RemoveDomainPrefixFromNetworkData();
	}

	mDomainPrefixConfig = aConfig;
	LogDomainPrefix("Set", kErrorNone);

	if (IsEnabled())
	{
	AddDomainPrefixToNetworkData();
	}

	exit:
	return error;
	}

	void Local::ApplyMeshLocalPrefix(void)
	{
	VerifyOrExit(IsEnabled());

	Get<BackboneTmfAgent>().UnsubscribeMulticast(mAllNetworkBackboneRouters);
	mAllNetworkBackboneRouters.SetMulticastNetworkPrefix(Get<Mle::MleRouter>().GetMeshLocalPrefix());
	Get<BackboneTmfAgent>().SubscribeMulticast(mAllNetworkBackboneRouters);

	if (IsPrimary())
	{
	Get<ThreadNetif>().RemoveUnicastAddress(mBackboneRouterPrimaryAloc);
	mBackboneRouterPrimaryAloc.GetAddress().SetPrefix(Get<Mle::MleRouter>().GetMeshLocalPrefix());
	Get<ThreadNetif>().AddUnicastAddress(mBackboneRouterPrimaryAloc);
	}

	exit:
	return;
	}

	void Local::HandleDomainPrefixUpdate(Leader::DomainPrefixState aState)
	{
	if (!IsEnabled())
	{
	ExitNow();
	}

	if (aState == Leader::kDomainPrefixRemoved \|\| aState == Leader::kDomainPrefixRefreshed)
	{
	Get<BackboneTmfAgent>().UnsubscribeMulticast(mAllDomainBackboneRouters);
	}

	if (aState == Leader::kDomainPrefixAdded \|\| aState == Leader::kDomainPrefixRefreshed)
	{
	mAllDomainBackboneRouters.SetMulticastNetworkPrefix(*Get<Leader>().GetDomainPrefix());
	Get<BackboneTmfAgent>().SubscribeMulticast(mAllDomainBackboneRouters);
	}

	if (mDomainPrefixCallback != nullptr)
	{
	switch (aState)
	{
	case Leader::kDomainPrefixAdded:
	mDomainPrefixCallback(mDomainPrefixCallbackContext, OT_BACKBONE_ROUTER_DOMAIN_PREFIX_ADDED,
	Get<Leader>().GetDomainPrefix());
	break;
	case Leader::kDomainPrefixRemoved:
	mDomainPrefixCallback(mDomainPrefixCallbackContext, OT_BACKBONE_ROUTER_DOMAIN_PREFIX_REMOVED,
	Get<Leader>().GetDomainPrefix());
	break;
	case Leader::kDomainPrefixRefreshed:
	mDomainPrefixCallback(mDomainPrefixCallbackContext, OT_BACKBONE_ROUTER_DOMAIN_PREFIX_CHANGED,
	Get<Leader>().GetDomainPrefix());
	break;
	default:
	break;
	}
	}

	exit:
	return;
	}

	void Local::RemoveDomainPrefixFromNetworkData(void)
	{
	Error error = kErrorNotFound; // only used for logging.

	if (mDomainPrefixConfig.mPrefix.mLength > 0)
	{
	error = Get<NetworkData::Local>().RemoveOnMeshPrefix(mDomainPrefixConfig.GetPrefix());
	}

	LogDomainPrefix("Remove", error);
	}

	void Local::SequenceNumberIncrease(void)
	{
	switch (mSequenceNumber)
	{
	case 126:
	case 127:
	mSequenceNumber = 0;
	break;
	case 254:
	case 255:
	mSequenceNumber = 128;
	break;
	default:
	mSequenceNumber++;
	break;
	}
	}

	void Local::AddDomainPrefixToNetworkData(void)
	{
	Error error = kErrorNotFound; // only used for logging.

	if (mDomainPrefixConfig.GetPrefix().GetLength() > 0)
	{
	error = Get<NetworkData::Local>().AddOnMeshPrefix(mDomainPrefixConfig);
	}

	LogDomainPrefix("Add", error);
	}

	#if (OPENTHREAD_CONFIG_LOG_LEVEL >= OT_LOG_LEVEL_INFO) && (OPENTHREAD_CONFIG_LOG_BBR == 1)
	void Local::LogDomainPrefix(const char *aAction, Error aError)
	{
	otLogInfoBbr("%s Domain Prefix: %s, %s", aAction, mDomainPrefixConfig.GetPrefix().ToString().AsCString(),
	ErrorToString(aError));
	}

	void Local::LogBackboneRouterService(const char *aAction, Error aError)
	{
	otLogInfoBbr("%s BBR Service: seqno (%d), delay (%ds), timeout (%ds), %s", aAction, mSequenceNumber,
	mReregistrationDelay, mMlrTimeout, ErrorToString(aError));
	}
	#endif

	void Local::SetDomainPrefixCallback(otBackboneRouterDomainPrefixCallback aCallback, void *aContext)
	{
	mDomainPrefixCallback = aCallback;
	mDomainPrefixCallbackContext = aContext;
	}

	#if OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE
	void Local::ConfigSkipSeqNumIncrease(bool aSkip)
	{
	mSkipSeqNumIncrease = aSkip;
	}
	#endif

	} // namespace BackboneRouter

	} // namespace ot

	#endif // OPENTHREAD_FTD && OPENTHREAD_CONFIG_BACKBONE_ROUTER_ENABLE