TI ZigBee协议栈中终端设备的状态切换详解

本文主要介绍了TI ZigBee协议栈Z-Stack中，关于终端设备End Device工作过程中，不同状态之间切换的详细说明，并且通过分析空中交互的数据包进一步了解TI ZigBee协议栈Z-Stack的工作流程。

• 终端设备在协议栈中涉及到的状态

在Z-Stack Home 1.2.2a协议栈的C:\Texas Instruments\Z-Stack Home 1.2.2a.44539\Components\stack\zdo\ZDApp.h文件中有定义设备的不同状态，分别如下。

typedef enum
{
  DEV_HOLD,                                // Initialized - not started automatically
  DEV_INIT,                                // Initialized - not connected to anything
  DEV_NWK_DISC,                            // Discovering PAN's to join
  DEV_NWK_JOINING,                         // Joining a PAN
  DEV_NWK_SEC_REJOIN_CURR_CHANNEL,         // ReJoining a PAN in secure mode scanning in current channel, only for end devices
  DEV_END_DEVICE_UNAUTH,                   // Joined but not yet authenticated by trust center
  DEV_END_DEVICE,                          // Started as device after authentication
  DEV_ROUTER,                              // Device joined, authenticated and is a router
  DEV_COORD_STARTING,                      // Started as Zigbee Coordinator
  DEV_ZB_COORD,                            // Started as Zigbee Coordinator
  DEV_NWK_ORPHAN,                          // Device has lost information about its parent..
  DEV_NWK_KA,                              // Device is sending KeepAlive message to its parent
  DEV_NWK_BACKOFF,                         // Device is waiting before trying to rejoin
  DEV_NWK_SEC_REJOIN_ALL_CHANNEL,          // ReJoining a PAN in secure mode scanning in all channels, only for end devices
  DEV_NWK_TC_REJOIN_CURR_CHANNEL,          // ReJoining a PAN in Trust center mode scanning in current channel, only for end devices
  DEV_NWK_TC_REJOIN_ALL_CHANNEL            // ReJoining a PAN in Trust center mode scanning in all channels, only for end devices
} devStates_t;

对于不同的设备类型会有不同的设备状态，那么对于终端设备来说可能使用到的设备如下。

DEV_HOLD,                                // Initialized - not started automatically
  DEV_INIT,                                // Initialized - not connected to anything
  DEV_NWK_DISC,                            // Discovering PAN's to join
  DEV_NWK_JOINING,                         // Joining a PAN
  DEV_NWK_SEC_REJOIN_CURR_CHANNEL,         // ReJoining a PAN in secure mode scanning in current channel, only for end devices
  DEV_END_DEVICE_UNAUTH,                   // Joined but not yet authenticated by trust center
  DEV_END_DEVICE,                          // Started as device after authentication
  DEV_NWK_ORPHAN,                          // Device has lost information about its parent..
  DEV_NWK_BACKOFF,                         // Device is waiting before trying to rejoin
  DEV_NWK_SEC_REJOIN_ALL_CHANNEL,          // ReJoining a PAN in secure mode scanning in all channels, only for end devices
  DEV_NWK_TC_REJOIN_CURR_CHANNEL,          // ReJoining a PAN in Trust center mode scanning in current channel, only for end devices
  DEV_NWK_TC_REJOIN_ALL_CHANNEL            // ReJoining a PAN in Trust center mode scanning in all channels, only for end devices

• 终端设备的状态机切换

// Start the device?
  if ( devState != DEV_HOLD )
  {
    ZDOInitDevice( 0 );
  }
  else
  {
    ZDOInitDevice( ZDO_INIT_HOLD_NWK_START );
    // Blink LED to indicate HOLD_START
    HalLedBlink ( HAL_LED_4, 0, 50, 500 );
  }

#if defined( HOLD_AUTO_START )
  devStates_t devState = DEV_HOLD;
#else
  devStates_t devState = DEV_INIT;
#endif

if ( events & ZDO_NETWORK_INIT )
  {
    // Initialize apps and start the network
    ZDApp_ChangeState( DEV_INIT );

    ZDO_StartDevice( (uint8)ZDO_Config_Node_Descriptor.LogicalType, devStartMode,
                     DEFAULT_BEACON_ORDER, DEFAULT_SUPERFRAME_ORDER );

    // Return unprocessed events
    return (events ^ ZDO_NETWORK_INIT);
  }

if ( ZG_BUILD_JOINING_TYPE && (logicalType == NODETYPE_ROUTER || logicalType == NODETYPE_DEVICE) )
  {
    if ( (startMode == MODE_JOIN) || (startMode == MODE_REJOIN) )
    {
      ZDApp_ChangeState( DEV_NWK_DISC );

if ( ( (pChosenNwk = ZDApp_NwkDescListProcessing()) != NULL ) && (zdoDiscCounter > NUM_DISC_ATTEMPTS) )

else
        {
          if ( continueJoining )
          {
#if defined ( MANAGED_SCAN )
            ZDApp_NetworkInit( MANAGEDSCAN_DELAY_BETWEEN_SCANS );
#else
            zdoDiscCounter++;
            ZDApp_NetworkInit( (uint16)(BEACON_REQUEST_DELAY
                                        + ((uint16)(osal_rand()& BEACON_REQ_DELAY_MASK))) );
#endif
          }
        }

if ( ( (pChosenNwk = ZDApp_NwkDescListProcessing()) != NULL ) && (zdoDiscCounter > NUM_DISC_ATTEMPTS) )
        {
          if ( devStartMode == MODE_JOIN )
          {
            ZDApp_ChangeState( DEV_NWK_JOINING );

            ZDApp_NodeProfileSync( pChosenNwk->stackProfile);

            if ( NLME_JoinRequest( pChosenNwk->extendedPANID, pChosenNwk->panId,
                                  pChosenNwk->logicalChannel,
                                  ZDO_Config_Node_Descriptor.CapabilityFlags,
                                  pChosenNwk->chosenRouter, pChosenNwk->chosenRouterDepth ) != ZSuccess )
            {
              ZDApp_NetworkInit( (uint16)(NWK_START_DELAY
                                          + ((uint16)(osal_rand()& EXTENDED_JOINING_RANDOM_MASK))) );
            }
          } // if ( devStartMode == MODE_JOIN )

终端设备在成功入网以后，状态成为了DEV_END_DEVICE。正常情况下该终端设备可以顺利的发送数据给父设备，也可以通过Data Request的方式向父设备获取发该子设备的数据。在实际应用层，可能出现终端设备移动，父设备掉电，因为干扰跟父设备通信多次失败，从而导致终端设备成为一个孤立的设备。如果连续发送数据没有收到父设备的MAC ACK，则触发设备进入孤立设备状态，调用到ZDO_SyncIndicationCB( uint8 type, uint16 shortAddr )函数，最后在ZDApp_ProcessOSALMsg( osal_event_hdr_t *msgPtr )触发下面的程序。

case ZDO_NWK_JOIN_REQ:
      if ( ZG_BUILD_JOINING_TYPE && ZG_DEVICE_JOINING_TYPE )
      {
        retryCnt = 0;
        devStartMode = MODE_RESUME;
        _tmpRejoinState = true;
        osal_cpyExtAddr( ZDO_UseExtendedPANID, _NIB.extendedPANID );
        zgDefaultStartingScanDuration = BEACON_ORDER_60_MSEC;
        ZDApp_NetworkInit( 0 );
      }
      break;

启动的状态已经是MODE_RESUME，程序有重新执行到ZDApp_event_loop( uint8 task_id, UINT16 events )中的下面代码，再次开启启动设备的过程。

if ( events & ZDO_NETWORK_INIT )
  {
    // Initialize apps and start the network
    ZDApp_ChangeState( DEV_INIT );

    ZDO_StartDevice( (uint8)ZDO_Config_Node_Descriptor.LogicalType, devStartMode,
                     DEFAULT_BEACON_ORDER, DEFAULT_SUPERFRAME_ORDER );

    // Return unprocessed events
    return (events ^ ZDO_NETWORK_INIT);
  }

最后执行到ZDO_StartDevice中的下面代码

else if ( startMode == MODE_RESUME )
    {
      if ( logicalType == NODETYPE_ROUTER )
      {
        ZMacScanCnf_t scanCnf;
        ZDApp_ChangeState( DEV_NWK_ORPHAN );

        /* if router and nvram is available, fake successful orphan scan */
        scanCnf.hdr.Status = ZSUCCESS;
        scanCnf.ScanType = ZMAC_ORPHAN_SCAN;
        scanCnf.UnscannedChannels = 0;
        scanCnf.ResultListSize = 0;
        nwk_ScanJoiningOrphan(&scanCnf);

        ret = ZSuccess;
      }
      else
      {
        ZDApp_ChangeState( DEV_NWK_ORPHAN );
        //set timer for scan and rejoin
        osal_start_timerEx( ZDAppTaskID, ZDO_REJOIN_BACKOFF, zgDefaultRejoinScan );
        ret = NLME_OrphanJoinRequest( runtimeChannel,
                                      zgDefaultStartingScanDuration );
      }
}

此时设备已经把状态从DEV_END_DEVICE状态切换到DEV_END_ORPHAN状态。通过调用NLME_OrphanJoinRequest函数向信道发送Orphan Notification告诉网络里面的设备，声明自己已经是一个孤立设备，这个Orphan Notification会在定义的每个信道上发送一次。

• DEV_END_ORPHAN状态到DEV_END_DEVICE状态（6）

节点在发出Orphan Notification以后，节点的状态从DEV_END_ORPHAN切换到了NWK_JOINING_ORPHAN状态，在这个状态下节点会在之前定义的信道上发送Orphan Notification消息，如果有原来的父设备回复了Coord Realignment，节点认为原先的父设备重新找到了，则会调用到ZDO_JoinConfirmCB( PanId, Status );再调用到ZDApp_ProcessOSALMsg( osal_event_hdr_t *msgPtr )中的

case ZDO_NWK_JOIN_IND:
      if ( ZG_BUILD_JOINING_TYPE && ZG_DEVICE_JOINING_TYPE )
      {
        ZDApp_ProcessNetworkJoin();
      }
      break;

然后再次到调用到ZDApp_AnnounceNewAddress();告诉网络里面的其他设备，再次加网成功了。这个时候节点的状态又切换到了DEV_END_DEVICE状态。

• DEV_END_ORPHAN状态到DEV_INIT状态（12）

节点从End Device状态到Orphan状态，并不是每次都能通过Orphan Scan的方式，重新找到原先的父设备。比方说父设备断电，被移动走，或因为网内其他数据干扰导致父设备回复的Coord Realignment没有收到。 

在这种情况下，节点开始重新搜索网络，而不是仅仅只找自己原先的父设备了。 如果在Orphan状态下，join失败的，也会调用到void ZDO_JoinConfirmCB( uint16 PanId, ZStatus_t Status )这个call back函数。再调用到ZDApp_ProcessOSALMsg( osal_event_hdr_t *msgPtr )

只不过这个时候的status变成了失败的状态。进入下面的代码。

void ZDApp_ProcessNetworkJoin( void )
......
else if ( devState == DEV_NWK_ORPHAN ||
            devState == DEV_NWK_SEC_REJOIN_CURR_CHANNEL ||
            devState == DEV_NWK_TC_REJOIN_CURR_CHANNEL ||
            devState == DEV_NWK_TC_REJOIN_ALL_CHANNEL ||
            devState == DEV_NWK_SEC_REJOIN_ALL_CHANNEL )
......

else
    {
      if ( devStartMode == MODE_RESUME )
      {
        if ( ++retryCnt <= MAX_RESUME_RETRY )
        {
          if ( _NIB.nwkPanId == 0xFFFF )
            devStartMode = MODE_JOIN;
          else
          {
            devStartMode = MODE_REJOIN;
            _tmpRejoinState = true;
            prevDevState = DEV_NWK_SEC_REJOIN_CURR_CHANNEL;
          }
        }
        // Do a normal join to the network after certain times of rejoin retries
        else if( AIB_apsUseInsecureJoin == true )
        {
          devStartMode = MODE_JOIN;
        }
      }
      else if(devStartMode == MODE_REJOIN)

此时设备的状态devState=DEV_NWK_ORPHAN，并且devStartMode=MODE_RESUME，所以程序会运行到devStartMode = MODE_REJOIN。

最后在ZDApp_ProcessNetworkJoin里面运行到下面代码，开始重新搜索网络了。

ZDApp_NetworkInit( (uint16)(NWK_START_DELAY
           + (osal_rand()& EXTENDED_JOINING_RANDOM_MASK)) );

程序再次执行到ZDApp_event_loop( uint8 task_id, UINT16 events )下面代码，此时的状态就变成了DEV_INIT状态。

if ( events & ZDO_NETWORK_INIT )
  {
    // Initialize apps and start the network
    ZDApp_ChangeState( DEV_INIT );

    ZDO_StartDevice( (uint8)ZDO_Config_Node_Descriptor.LogicalType, devStartMode,
                     DEFAULT_BEACON_ORDER, DEFAULT_SUPERFRAME_ORDER );

    // Return unprocessed events
    return (events ^ ZDO_NETWORK_INIT);
  }

• DEV_INIT状态到DEV_NWK_DISC（1）

在进入DEV_INIT状态以后，进入ZDO_StartDevice()函数，因为设备的startmode是MODE_REJOIN，所以按照下面的代码，进入discover状态

if ( ZG_BUILD_JOINING_TYPE && (logicalType == NODETYPE_ROUTER || logicalType == NODETYPE_DEVICE) )
  {
    if ( (startMode == MODE_JOIN) || (startMode == MODE_REJOIN) )
    {
      ZDApp_ChangeState( DEV_NWK_DISC );

  #if defined( MANAGED_SCAN )
      ZDOManagedScan_Next();
      ret = NLME_NetworkDiscoveryRequest( managedScanChannelMask, BEACON_ORDER_15_MSEC );
#else
      ret = NLME_NetworkDiscoveryRequest( runtimeChannel, zgDefaultStartingScanDuration );
#if defined ( ZIGBEE_FREQ_AGILITY )
      if ( !( ZDO_Config_Node_Descriptor.CapabilityFlags & CAPINFO_RCVR_ON_IDLE ) &&
          ( ret == ZSuccess ) && ( ++discRetries == 4 ) )
      {
        // For devices with RxOnWhenIdle equals to FALSE, any network channel
        // change will not be recieved. On these devices or routers that have
        // lost the network, an active scan shall be conducted on the Default
        // Channel list using the extended PANID to find the network. If the
        // extended PANID isn't found using the Default Channel list, an scan
        // should be completed using all channels.
        runtimeChannel = MAX_CHANNELS_24GHZ;
      }
    #endif // ZIGBEE_FREQ_AGILITY

• DEV_NWK_DISC状态到DEV_NWK_REJOIN（8）

跟之前的状态2中，进入discovery状态以后做的事情一样，去信道上扫描原先的网络。但是这个时候不会去所有信道扫描了，只在刚才网络的信道扫描，因为默认认为网络的信道时不会改变的。

在扫描过程结束以后，程序同样执行到了NLME_NetworkDiscoveryConfirm(uint8 status)-> ZDO_NetworkDiscoveryConfirmCB(status)-> ZDApp_SendMsg( ZDAppTaskID, ZDO_NWK_DISC_CNF, sizeof(osal_event_hdr_t), (uint8 *)&msg );-> ZDApp_ProcessOSALMsg( osal_event_hdr_t *msgPtr )下面的case ZDO_NWK_DISC_CNF:

case ZDO_NWK_DISC_CNF:
      if (devState != DEV_NWK_DISC)
        break;

      if ( ZG_BUILD_JOINING_TYPE && ZG_DEVICE_JOINING_TYPE )
      {
        // Process the network discovery scan results and choose a parent
        // device to join/rejoin itself
        networkDesc_t *pChosenNwk;
        if ( ( (pChosenNwk = ZDApp_NwkDescListProcessing()) != NULL ) && (zdoDiscCounter > NUM_DISC_ATTEMPTS) )
        {
.....................

 else if ( devStartMode == MODE_REJOIN )
          {
            ZStatus_t rejoinStatus;

            // Transition state machine to correct rejoin state based on previous state before network discovery
            if ( ZDApp_RestoreNwkKey( FALSE )== TRUE )
............................
// Perform Secure or Unsecure Rejoin depending on available configuration
            if ( ZG_SECURE_ENABLED && ( ZDApp_RestoreNwkKey( TRUE ) == TRUE ) )
            {
              rejoinStatus = NLME_ReJoinRequest( ZDO_UseExtendedPANID, pChosenNwk->logicalChannel);
            }
            else
            {
              rejoinStatus = NLME_ReJoinRequestUnsecure( ZDO_UseExtendedPANID, pChosenNwk->logicalChannel);
            }

            if ( rejoinStatus != ZSuccess )
            {
              ZDApp_NetworkInit( (uint16)(NWK_START_DELAY
                                          + ((uint16)(osal_rand()& EXTENDED_JOINING_RANDOM_MASK))) );
            }

由于此次扫描前start mode的状态，会开始进入rejoin状态，通过调用NLME_ReJoinRequest( ZDO_UseExtendedPANID, pChosenNwk->logicalChannel);来发送Rejoin Request消息。

• DEV_NWK_REJOIN状态到DEV_END_DEVICE（15）

else if ( devState == DEV_NWK_ORPHAN ||
            devState == DEV_NWK_SEC_REJOIN_CURR_CHANNEL ||
            devState == DEV_NWK_TC_REJOIN_CURR_CHANNEL ||
            devState == DEV_NWK_TC_REJOIN_ALL_CHANNEL ||
            devState == DEV_NWK_SEC_REJOIN_ALL_CHANNEL )
  {
......................
 // results of an orphaning attempt by this device
     // results of an orphaning attempt by this device
   if (nwkStatus == ZSuccess)
    {
      //When the device has successfully rejoined then reset retryCnt
      retryCnt = 0;

      // Verify NWK key is available before sending Device_annce
      if ( ZG_SECURE_ENABLED && ( ZDApp_RestoreNwkKey( TRUE ) == false ) )
      {
        // wait for auth from trust center
        ZDApp_ChangeState( DEV_END_DEVICE_UNAUTH );

        // Start the reset timer for MAX UNAUTH time
        ZDApp_ResetTimerStart( MAX_DEVICE_UNAUTH_TIMEOUT );
      }
      else
      {
        ZDApp_ChangeState( DEV_END_DEVICE );

        osal_stop_timerEx( ZDAppTaskID, ZDO_REJOIN_BACKOFF );

        // setup Power Manager Device
#if defined ( POWER_SAVING )
        osal_pwrmgr_device( PWRMGR_BATTERY );
#endif

        // The receiver is on, turn network layer polling off.
        if ( ZDO_Config_Node_Descriptor.CapabilityFlags & CAPINFO_RCVR_ON_IDLE )
        {
          // if Child Table Management process is not enabled
          if ( zgChildAgingEnable == FALSE )
          {
            NLME_SetPollRate( 0 );
            NLME_SetQueuedPollRate( 0 );
            NLME_SetResponseRate( 0 );
          }
        }

        if ( ZSTACK_ROUTER_BUILD )
        {
          // NOTE: first two parameters are not used, see NLMEDE.h for details
          if ( ZDO_Config_Node_Descriptor.LogicalType != NODETYPE_DEVICE )
          {
            NLME_StartRouterRequest( 0, 0, false );
          }
        }

        ZDApp_AnnounceNewAddress();

        if ( ( (ZDO_Config_Node_Descriptor.CapabilityFlags & CAPINFO_RCVR_ON_IDLE) == 0 )
            || ( (ZDO_Config_Node_Descriptor.CapabilityFlags & CAPINFO_RCVR_ON_IDLE)
              && (zgChildAgingEnable == TRUE) ) )
        {
          NLME_SetPollRate( ZDApp_SavedPollRate );
        }
      }
    }

最后终端发出ZDApp_AnnounceNewAddress();再次广播网络里面的设备，节点Rejoin加网成功了，并且状态又重新迁移到DEV_END_DEVICE 状态。

else if ( devStartMode == MODE_REJOIN )
          {
            ZStatus_t rejoinStatus;

            // Transition state machine to correct rejoin state based on previous state before network discovery
            if ( ZDApp_RestoreNwkKey( FALSE )== TRUE )
............................
// Perform Secure or Unsecure Rejoin depending on available configuration
            if ( ZG_SECURE_ENABLED && ( ZDApp_RestoreNwkKey( TRUE ) == TRUE ) )
            {
              rejoinStatus = NLME_ReJoinRequest( ZDO_UseExtendedPANID, pChosenNwk->logicalChannel);
            }
            else
            {
              rejoinStatus = NLME_ReJoinRequestUnsecure( ZDO_UseExtendedPANID, pChosenNwk->logicalChannel);
            }

            if ( rejoinStatus != ZSuccess )
            {
              ZDApp_NetworkInit( (uint16)(NWK_START_DELAY
                                          + ((uint16)(osal_rand()& EXTENDED_JOINING_RANDOM_MASK))) );
            }

if ( ZG_SECURE_ENABLED && ( ZDApp_RestoreNwkKey( TRUE ) == false ) )
      {
        // wait for auth from trust center
        ZDApp_ChangeState( DEV_END_DEVICE_UNAUTH );

        // Start the reset timer for MAX UNAUTH time
        ZDApp_ResetTimerStart( MAX_DEVICE_UNAUTH_TIMEOUT );
      }
      else
      {

• DEV_END_DEVICE_UNAUTH状态到DEV_NWK_ORPHAN（14）

未完待续