[child-table] move StateFilter definition to Neighbor (#4419)

src/core/mac/data_poll_handler.cpp

@@ -79,7 +79,7 @@ DataPollHandler::DataPollHandler(Instance &aInstance)
 
 void DataPollHandler::Clear(void)
 {
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
     {
         Child &child = *iter.GetChild();
         child.SetDataPollPending(false);
@@ -134,7 +134,7 @@ void DataPollHandler::HandleDataPoll(Mac::RxFrame &aFrame)
     VerifyOrExit(Get<Mle::MleRouter>().GetRole() != OT_DEVICE_ROLE_DETACHED);
 
     SuccessOrExit(aFrame.GetSrcAddr(macSource));
-    child = Get<ChildTable>().FindChild(macSource, ChildTable::kInStateValidOrRestoring);
+    child = Get<ChildTable>().FindChild(macSource, Child::kInStateValidOrRestoring);
     VerifyOrExit(child != NULL);
 
     child->SetLastHeard(TimerMilli::GetNow());
@@ -289,7 +289,7 @@ exit:
 
 void DataPollHandler::ProcessPendingPolls(void)
 {
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone(); iter++)
     {
         Child *child = iter.GetChild();
 

src/core/thread/address_resolver.cpp

@@ -600,7 +600,7 @@ void AddressResolver::HandleAddressError(Coap::Message &aMessage, const Ip6::Mes
     macAddr.Set(mlIidTlv.GetIid());
     macAddr.ToggleLocal();
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValid); !iter.IsDone(); iter++)
     {
         Child &child = *iter.GetChild();
 
@@ -666,7 +666,7 @@ void AddressResolver::HandleAddressQuery(Coap::Message &aMessage, const Ip6::Mes
         ExitNow();
     }
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValid); !iter.IsDone(); iter++)
     {
         Child &child = *iter.GetChild();
 

src/core/thread/child_table.cpp

@@ -41,7 +41,7 @@ namespace ot {
 
 #if OPENTHREAD_FTD
 
-ChildTable::Iterator::Iterator(Instance &aInstance, StateFilter aFilter)
+ChildTable::Iterator::Iterator(Instance &aInstance, Child::StateFilter aFilter)
     : InstanceLocator(aInstance)
     , mFilter(aFilter)
     , mStart(NULL)
@@ -50,7 +50,7 @@ ChildTable::Iterator::Iterator(Instance &aInstance, StateFilter aFilter)
     Reset();
 }
 
-ChildTable::Iterator::Iterator(Instance &aInstance, StateFilter aFilter, Child *aStartingChild)
+ChildTable::Iterator::Iterator(Instance &aInstance, Child::StateFilter aFilter, Child *aStartingChild)
     : InstanceLocator(aInstance)
     , mFilter(aFilter)
     , mStart(aStartingChild)
@@ -68,7 +68,7 @@ void ChildTable::Iterator::Reset(void)
 
     mChild = mStart;
 
-    if (!MatchesFilter(*mChild, mFilter))
+    if (!mChild->MatchesFilter(mFilter))
     {
         Advance();
     }
@@ -92,7 +92,7 @@ void ChildTable::Iterator::Advance(void)
         }
 
         VerifyOrExit(mChild != mStart, mChild = NULL);
-    } while (!MatchesFilter(*mChild, mFilter));
+    } while (!mChild->MatchesFilter(mFilter));
 
 exit:
     return;
@@ -143,13 +143,13 @@ exit:
     return child;
 }
 
-Child *ChildTable::FindChild(uint16_t aRloc16, StateFilter aFilter)
+Child *ChildTable::FindChild(uint16_t aRloc16, Child::StateFilter aFilter)
 {
     Child *child = mChildren;
 
     for (uint16_t num = mMaxChildrenAllowed; num != 0; num--, child++)
     {
-        if (MatchesFilter(*child, aFilter) && (child->GetRloc16() == aRloc16))
+        if (child->MatchesFilter(aFilter) && (child->GetRloc16() == aRloc16))
         {
             ExitNow();
         }
@@ -161,13 +161,13 @@ exit:
     return child;
 }
 
-Child *ChildTable::FindChild(const Mac::ExtAddress &aAddress, StateFilter aFilter)
+Child *ChildTable::FindChild(const Mac::ExtAddress &aAddress, Child::StateFilter aFilter)
 {
     Child *child = mChildren;
 
     for (uint16_t num = mMaxChildrenAllowed; num != 0; num--, child++)
     {
-        if (MatchesFilter(*child, aFilter) && (child->GetExtAddress() == aAddress))
+        if (child->MatchesFilter(aFilter) && (child->GetExtAddress() == aAddress))
         {
             ExitNow();
         }
@@ -179,7 +179,7 @@ exit:
     return child;
 }
 
-Child *ChildTable::FindChild(const Mac::Address &aAddress, StateFilter aFilter)
+Child *ChildTable::FindChild(const Mac::Address &aAddress, Child::StateFilter aFilter)
 {
     Child *child = NULL;
 
@@ -200,14 +200,14 @@ Child *ChildTable::FindChild(const Mac::Address &aAddress, StateFilter aFilter)
     return child;
 }
 
-bool ChildTable::HasChildren(StateFilter aFilter) const
+bool ChildTable::HasChildren(Child::StateFilter aFilter) const
 {
     bool         rval  = false;
     const Child *child = mChildren;
 
     for (uint16_t num = mMaxChildrenAllowed; num != 0; num--, child++)
     {
-        if (MatchesFilter(*child, aFilter))
+        if (child->MatchesFilter(aFilter))
         {
             ExitNow(rval = true);
         }
@@ -217,14 +217,14 @@ exit:
     return rval;
 }
 
-uint16_t ChildTable::GetNumChildren(StateFilter aFilter) const
+uint16_t ChildTable::GetNumChildren(Child::StateFilter aFilter) const
 {
     uint16_t     numChildren = 0;
     const Child *child       = mChildren;
 
     for (uint16_t num = mMaxChildrenAllowed; num != 0; num--, child++)
     {
-        if (MatchesFilter(*child, aFilter))
+        if (child->MatchesFilter(aFilter))
         {
             numChildren++;
         }
@@ -238,7 +238,7 @@ otError ChildTable::SetMaxChildrenAllowed(uint16_t aMaxChildren)
     otError error = OT_ERROR_NONE;
 
     VerifyOrExit(aMaxChildren > 0 && aMaxChildren <= kMaxChildren, error = OT_ERROR_INVALID_ARGS);
-    VerifyOrExit(!HasChildren(kInStateAnyExceptInvalid), error = OT_ERROR_INVALID_STATE);
+    VerifyOrExit(!HasChildren(Child::kInStateAnyExceptInvalid), error = OT_ERROR_INVALID_STATE);
 
     mMaxChildrenAllowed = aMaxChildren;
 
@@ -246,40 +246,6 @@ exit:
     return error;
 }
 
-bool ChildTable::MatchesFilter(const Child &aChild, StateFilter aFilter)
-{
-    bool rval = false;
-
-    switch (aFilter)
-    {
-    case kInStateValid:
-        rval = aChild.IsStateValid();
-        break;
-
-    case kInStateValidOrRestoring:
-        rval = aChild.IsStateValidOrRestoring();
-        break;
-
-    case kInStateChildIdRequest:
-        rval = aChild.IsStateChildIdRequest();
-        break;
-
-    case kInStateValidOrAttaching:
-        rval = aChild.IsStateValidOrAttaching();
-        break;
-
-    case kInStateAnyExceptInvalid:
-        rval = !aChild.IsStateInvalid();
-        break;
-
-    case kInStateAnyExceptValidOrRestoring:
-        rval = !aChild.IsStateValidOrRestoring();
-        break;
-    }
-
-    return rval;
-}
-
 #endif // OPENTHREAD_FTD
 
 } // namespace ot

src/core/thread/child_table.hpp

@@ -50,22 +50,6 @@ namespace ot {
 class ChildTable : public InstanceLocator
 {
 public:
-    /**
-     * This enumeration defines child state filters used for finding a child or iterating through the child table.
-     *
-     * Each filter definition accepts a subset of `Child:State` values.
-     *
-     */
-    enum StateFilter
-    {
-        kInStateValid,                     ///< Accept child only in `Child::kStateValid`.
-        kInStateValidOrRestoring,          ///< Accept child with `Child::IsStateValidOrRestoring()` being `true`.
-        kInStateChildIdRequest,            ///< Accept child only in `Child:kStateChildIdRequest`.
-        kInStateValidOrAttaching,          ///< Accept child with `Child::IsStateValidOrAttaching()` being `true`.
-        kInStateAnyExceptInvalid,          ///< Accept child in any state except `Child:kStateInvalid`.
-        kInStateAnyExceptValidOrRestoring, ///< Accept child in any state except `Child::IsStateValidOrRestoring()`.
-    };
-
     /**
      * This class represents an iterator for iterating through the child entries in the child table.
      *
@@ -80,7 +64,7 @@ public:
          * @param[in] aFilter    A child state filter.
          *
          */
-        Iterator(Instance &aInstance, StateFilter aFilter);
+        Iterator(Instance &aInstance, Child::StateFilter aFilter);
 
         /**
          * This constructor initializes an `Iterator` instance to start from a given child.
@@ -96,7 +80,7 @@ public:
          * @param[in] aStartingChild   A pointer to a child. If non-NULL, the iterator starts from the given entry.
          *
          */
-        Iterator(Instance &aInstance, StateFilter aFilter, Child *aStartingChild);
+        Iterator(Instance &aInstance, Child::StateFilter aFilter, Child *aStartingChild);
 
         /**
          * This method resets the iterator to start over.
@@ -153,9 +137,9 @@ public:
         Child *GetChild(void) { return mChild; }
 
     private:
-        StateFilter mFilter;
-        Child *     mStart;
-        Child *     mChild;
+        Child::StateFilter mFilter;
+        Child *            mStart;
+        Child *            mChild;
     };
 
     /**
@@ -212,7 +196,7 @@ public:
      * @returns  A pointer to the `Child` entry if one is found, or `NULL` otherwise.
      *
      */
-    Child *FindChild(uint16_t aRloc16, StateFilter aFilter);
+    Child *FindChild(uint16_t aRloc16, Child::StateFilter aFilter);
 
     /**
      * This method searches the child table for a `Child` with a given extended address also matching a given state
@@ -224,7 +208,7 @@ public:
      * @returns  A pointer to the `Child` entry if one is found, or `NULL` otherwise.
      *
      */
-    Child *FindChild(const Mac::ExtAddress &aAddress, StateFilter aFilter);
+    Child *FindChild(const Mac::ExtAddress &aAddress, Child::StateFilter aFilter);
 
     /**
      * This method searches the child table for a `Child` with a given address also matching a given state filter.
@@ -235,7 +219,7 @@ public:
      * @returns  A pointer to the `Child` entry if one is found, or `NULL` otherwise.
      *
      */
-    Child *FindChild(const Mac::Address &aAddress, StateFilter aFilter);
+    Child *FindChild(const Mac::Address &aAddress, Child::StateFilter aFilter);
 
     /**
      * This method indicates whether the child table contains any child matching a given state filter.
@@ -245,7 +229,7 @@ public:
      * @returns  TRUE if the table contains at least one child table matching the given filter, FALSE otherwise.
      *
      */
-    bool HasChildren(StateFilter aFilter) const;
+    bool HasChildren(Child::StateFilter aFilter) const;
 
     /**
      * This method returns the number of children in the child table matching a given state filter.
@@ -255,7 +239,7 @@ public:
      * @returns Number of children matching the given state filer.
      *
      */
-    uint16_t GetNumChildren(StateFilter aFilter) const;
+    uint16_t GetNumChildren(Child::StateFilter aFilter) const;
 
     /**
      * This method returns the maximum number of children that can be supported (build-time constant).
@@ -297,8 +281,6 @@ private:
         kMaxChildren = OPENTHREAD_CONFIG_MLE_MAX_CHILDREN,
     };
 
-    static bool MatchesFilter(const Child &aChild, StateFilter aFilter);
-
     uint16_t mMaxChildrenAllowed;
     Child    mChildren[kMaxChildren];
 };
@@ -310,20 +292,11 @@ private:
 class ChildTable : public InstanceLocator
 {
 public:
-    enum StateFilter
-    {
-        kInStateValid,
-        kInStateValidOrRestoring,
-        kInStateChildIdRequest,
-        kInStateValidOrAttaching,
-        kInStateAnyExceptInvalid,
-    };
-
     class Iterator
     {
     public:
-        Iterator(Instance &, StateFilter) {}
-        Iterator(Instance &, StateFilter, Child *) {}
+        Iterator(Instance &, Child::StateFilter) {}
+        Iterator(Instance &, Child::StateFilter, Child *) {}
         void   Reset(void) {}
         bool   IsDone(void) const { return true; }
         void   Advance(void) {}
@@ -343,12 +316,12 @@ public:
 
     Child *GetNewChild(void) { return NULL; }
 
-    Child *FindChild(uint16_t, StateFilter) { return NULL; }
-    Child *FindChild(const Mac::ExtAddress &, StateFilter) { return NULL; }
-    Child *FindChild(const Mac::Address &, StateFilter) { return NULL; }
+    Child *FindChild(uint16_t, Child::StateFilter) { return NULL; }
+    Child *FindChild(const Mac::ExtAddress &, Child::StateFilter) { return NULL; }
+    Child *FindChild(const Mac::Address &, Child::StateFilter) { return NULL; }
 
-    bool     HasChildren(StateFilter) const { return false; }
-    uint16_t GetNumChildren(StateFilter) const { return 0; }
+    bool     HasChildren(Child::StateFilter) const { return false; }
+    uint16_t GetNumChildren(Child::StateFilter) const { return 0; }
     uint16_t GetMaxChildren(void) const { return 0; }
     uint16_t GetMaxChildrenAllowed(void) const { return 0; }
     otError  SetMaxChildrenAllowed(uint16_t) { return OT_ERROR_INVALID_STATE; }

src/core/thread/indirect_sender.cpp

@@ -72,7 +72,7 @@ void IndirectSender::Stop(void)
 {
     VerifyOrExit(mEnabled);
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
     {
         iter.GetChild()->SetIndirectMessage(NULL);
         mSourceMatchController.ResetMessageCount(*iter.GetChild());
@@ -557,8 +557,7 @@ exit:
 
 void IndirectSender::ClearMessagesForRemovedChildren(void)
 {
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateAnyExceptValidOrRestoring); !iter.IsDone();
-         iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateAnyExceptValidOrRestoring); !iter.IsDone(); iter++)
     {
         if (iter.GetChild()->GetIndirectMessageCount() == 0)
         {

src/core/thread/key_manager.cpp

@@ -133,7 +133,7 @@ otError KeyManager::SetMasterKey(const MasterKey &aKey)
     }
 
     // reset child frame counters
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
     {
         iter.GetChild()->SetKeySequence(0);
         iter.GetChild()->SetLinkFrameCounter(0);

src/core/thread/mesh_forwarder.cpp

@@ -140,7 +140,7 @@ exit:
 void MeshForwarder::RemoveMessage(Message &aMessage)
 {
 #if OPENTHREAD_FTD
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
     {
         IgnoreReturnValue(mIndirectSender.RemoveMessageFromSleepyChild(aMessage, *iter.GetChild()));
     }

src/core/thread/mesh_forwarder_ftd.cpp

@@ -80,7 +80,7 @@ otError MeshForwarder::SendMessage(Message &aMessage)
                     ip6Header.GetDestination() == mle.GetRealmLocalAllThreadNodesAddress())
                 {
                     // destined for all sleepy children
-                    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone();
+                    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone();
                          iter++)
                     {
                         Child &child = *iter.GetChild();
@@ -94,7 +94,7 @@ otError MeshForwarder::SendMessage(Message &aMessage)
                 else
                 {
                     // destined for some sleepy children which subscribed the multicast address.
-                    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone();
+                    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone();
                          iter++)
                     {
                         Child &child = *iter.GetChild();
@@ -296,7 +296,7 @@ void MeshForwarder::RemoveDataResponseMessages(void)
 
         if (!(ip6Header.GetDestination().IsMulticast()))
         {
-            for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
+            for (ChildTable::Iterator iter(GetInstance(), Child::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
             {
                 IgnoreReturnValue(mIndirectSender.RemoveMessageFromSleepyChild(*message, *iter.GetChild()));
             }

src/core/thread/mle_router.cpp

@@ -319,7 +319,7 @@ void MleRouter::SetStateRouter(uint16_t aRloc16)
     Get<Mac::Mac>().SetBeaconEnabled(true);
 
     // remove children that do not have matching RLOC16
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone(); iter++)
     {
         if (GetRouterId(iter.GetChild()->GetRloc16()) != mRouterId)
         {
@@ -356,7 +356,7 @@ void MleRouter::SetStateLeader(uint16_t aRloc16)
     Get<AddressResolver>().Clear();
 
     // remove children that do not have matching RLOC16
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone(); iter++)
     {
         if (GetRouterId(iter.GetChild()->GetRloc16()) != mRouterId)
         {
@@ -1653,7 +1653,7 @@ otError MleRouter::HandleParentRequest(const Message &aMessage, const Ip6::Messa
     SuccessOrExit(error = Tlv::GetTlv(aMessage, Tlv::kChallenge, sizeof(challenge), challenge));
     VerifyOrExit(challenge.IsValid(), error = OT_ERROR_PARSE);
 
-    child = mChildTable.FindChild(macAddr, ChildTable::kInStateAnyExceptInvalid);
+    child = mChildTable.FindChild(macAddr, Child::kInStateAnyExceptInvalid);
 
     if (child == NULL)
     {
@@ -1799,7 +1799,7 @@ void MleRouter::HandleStateUpdateTimer(void)
     }
 
     // update children state
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
     {
         Child &  child   = *iter.GetChild();
         uint32_t timeout = 0;
@@ -2052,7 +2052,7 @@ otError MleRouter::UpdateChildAddresses(const Message &aMessage, uint16_t aOffse
         // table is timed out and then trying to register its globally unique
         // IPv6 address as the new child.
 
-        for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone(); iter++)
+        for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone(); iter++)
         {
             if (iter.GetChild() == &aChild)
             {
@@ -2112,7 +2112,7 @@ otError MleRouter::HandleChildIdRequest(const Message &         aMessage,
     // Find Child
     aMessageInfo.GetPeerAddr().ToExtAddress(macAddr);
 
-    child = mChildTable.FindChild(macAddr, ChildTable::kInStateAnyExceptInvalid);
+    child = mChildTable.FindChild(macAddr, Child::kInStateAnyExceptInvalid);
     VerifyOrExit(child != NULL, error = OT_ERROR_ALREADY);
 
     // Response
@@ -2289,7 +2289,7 @@ otError MleRouter::HandleChildUpdateRequest(const Message &         aMessage,
 
     // Find Child
     aMessageInfo.GetPeerAddr().ToExtAddress(macAddr);
-    child = mChildTable.FindChild(macAddr, ChildTable::kInStateAnyExceptInvalid);
+    child = mChildTable.FindChild(macAddr, Child::kInStateAnyExceptInvalid);
 
     tlvs[tlvslength++] = Tlv::kSourceAddress;
 
@@ -2616,7 +2616,7 @@ void MleRouter::SynchronizeChildNetworkData(void)
 {
     VerifyOrExit(mRole == OT_DEVICE_ROLE_ROUTER || mRole == OT_DEVICE_ROLE_LEADER);
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValid); !iter.IsDone(); iter++)
     {
         Child & child = *iter.GetChild();
         uint8_t version;
@@ -2889,7 +2889,7 @@ otError MleRouter::SendChildIdResponse(Child &aChild)
 
             rloc16 = Get<Mac::Mac>().GetShortAddress() | mNextChildId;
 
-        } while (mChildTable.FindChild(rloc16, ChildTable::kInStateAnyExceptInvalid) != NULL);
+        } while (mChildTable.FindChild(rloc16, Child::kInStateAnyExceptInvalid) != NULL);
 
         // allocate Child ID
         aChild.SetRloc16(rloc16);
@@ -3250,7 +3250,7 @@ Neighbor *MleRouter::GetNeighbor(uint16_t aAddress)
 
     case OT_DEVICE_ROLE_ROUTER:
     case OT_DEVICE_ROLE_LEADER:
-        rval = mChildTable.FindChild(aAddress, ChildTable::kInStateValidOrRestoring);
+        rval = mChildTable.FindChild(aAddress, Child::kInStateValidOrRestoring);
         VerifyOrExit(rval == NULL);
 
         rval = mRouterTable.GetNeighbor(aAddress);
@@ -3277,7 +3277,7 @@ Neighbor *MleRouter::GetNeighbor(const Mac::ExtAddress &aAddress)
 
     case OT_DEVICE_ROLE_ROUTER:
     case OT_DEVICE_ROLE_LEADER:
-        rval = mChildTable.FindChild(aAddress, ChildTable::kInStateValidOrRestoring);
+        rval = mChildTable.FindChild(aAddress, Child::kInStateValidOrRestoring);
         VerifyOrExit(rval == NULL);
 
         rval = mRouterTable.GetNeighbor(aAddress);
@@ -3347,7 +3347,7 @@ Neighbor *MleRouter::GetNeighbor(const Ip6::Address &aAddress)
         context.mContextId = 0xff;
     }
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone(); iter++)
     {
         child = iter.GetChild();
 
@@ -3507,7 +3507,7 @@ otError MleRouter::GetChildInfoById(uint16_t aChildId, otChildInfo &aChildInfo)
     }
 
     rloc16 = Get<Mac::Mac>().GetShortAddress() | aChildId;
-    child  = mChildTable.FindChild(rloc16, ChildTable::kInStateAnyExceptInvalid);
+    child  = mChildTable.FindChild(rloc16, Child::kInStateAnyExceptInvalid);
     VerifyOrExit(child != NULL, error = OT_ERROR_NOT_FOUND);
 
     error = GetChildInfo(*child, aChildInfo);
@@ -3559,7 +3559,7 @@ void MleRouter::RestoreChildren(void)
         const Settings::ChildInfo &childInfo = iter.GetChildInfo();
 
         child = mChildTable.FindChild(*static_cast<const Mac::ExtAddress *>(&childInfo.mExtAddress),
-                                      ChildTable::kInStateAnyExceptInvalid);
+                                      Child::kInStateAnyExceptInvalid);
 
         if (child == NULL)
         {
@@ -3635,7 +3635,7 @@ otError MleRouter::RefreshStoredChildren(void)
 
     SuccessOrExit(error = Get<Settings>().DeleteChildInfo());
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateAnyExceptInvalid); !iter.IsDone(); iter++)
     {
         SuccessOrExit(error = StoreChild(*iter.GetChild()));
     }
@@ -3802,7 +3802,7 @@ otError MleRouter::CheckReachability(uint16_t aMeshSource, uint16_t aMeshDest, I
     else if (GetRouterId(aMeshDest) == mRouterId)
     {
         // mesh destination is a child of this device
-        if (mChildTable.FindChild(aMeshDest, ChildTable::kInStateValidOrRestoring))
+        if (mChildTable.FindChild(aMeshDest, Child::kInStateValidOrRestoring))
         {
             ExitNow();
         }
@@ -4008,7 +4008,7 @@ void MleRouter::HandleAddressSolicitResponse(Coap::Message *         aMessage,
     SendLinkRequest(NULL);
 
     // send child id responses
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateChildIdRequest); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateChildIdRequest); !iter.IsDone(); iter++)
     {
         SendChildIdResponse(*iter.GetChild());
     }
@@ -4215,7 +4215,7 @@ void MleRouter::FillConnectivityTlv(ConnectivityTlv &aTlv)
     }
     else
     {
-        uint16_t numChildren = mChildTable.GetNumChildren(ChildTable::kInStateValid);
+        uint16_t numChildren = mChildTable.GetNumChildren(Child::kInStateValid);
         uint16_t maxAllowed  = mChildTable.GetMaxChildrenAllowed();
 
         if ((maxAllowed - numChildren) < (maxAllowed / 3))
@@ -4575,12 +4575,12 @@ exit:
 
 bool MleRouter::HasChildren(void)
 {
-    return mChildTable.HasChildren(ChildTable::kInStateValidOrAttaching);
+    return mChildTable.HasChildren(Child::kInStateValidOrAttaching);
 }
 
 void MleRouter::RemoveChildren(void)
 {
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone(); iter++)
     {
         RemoveNeighbor(*iter.GetChild());
     }
@@ -4593,7 +4593,7 @@ bool MleRouter::HasSmallNumberOfChildren(void)
 
     VerifyOrExit(routerCount > mRouterDowngradeThreshold);
 
-    numChildren = mChildTable.GetNumChildren(ChildTable::kInStateValid);
+    numChildren = mChildTable.GetNumChildren(Child::kInStateValid);
 
     return numChildren < (routerCount - mRouterDowngradeThreshold) * 3;
 
@@ -4620,7 +4620,7 @@ otError MleRouter::GetMaxChildTimeout(uint32_t &aTimeout) const
 
     VerifyOrExit(mRole == OT_DEVICE_ROLE_ROUTER || mRole == OT_DEVICE_ROLE_LEADER, error = OT_ERROR_INVALID_STATE);
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValid); !iter.IsDone(); iter++)
     {
         Child &child = *iter.GetChild();
 
@@ -4686,7 +4686,7 @@ bool MleRouter::HasSleepyChildrenSubscribed(const Ip6::Address &aAddress)
 {
     bool rval = false;
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone(); iter++)
     {
         Child &child = *iter.GetChild();
 

src/core/thread/network_diagnostic.cpp

@@ -230,7 +230,7 @@ otError NetworkDiagnostic::AppendChildTable(Message &aMessage)
 
     tlv.Init();
 
-    count = Get<ChildTable>().GetNumChildren(ChildTable::kInStateValid);
+    count = Get<ChildTable>().GetNumChildren(Child::kInStateValid);
 
     // The length of the Child Table TLV may exceed the outgoing link's MTU (1280B).
     // As a workaround we limit the number of entries in the Child Table TLV,
@@ -245,7 +245,7 @@ otError NetworkDiagnostic::AppendChildTable(Message &aMessage)
 
     SuccessOrExit(error = aMessage.Append(&tlv, sizeof(ChildTableTlv)));
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValid); !iter.IsDone(); iter++)
     {
         VerifyOrExit(count--);
 

src/core/thread/src_match_controller.cpp

@@ -210,7 +210,7 @@ otError SourceMatchController::AddPendingEntries(void)
 {
     otError error = OT_ERROR_NONE;
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValidOrRestoring); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValidOrRestoring); !iter.IsDone(); iter++)
     {
         if (iter.GetChild()->IsIndirectSourceMatchPending())
         {

src/core/thread/topology.cpp

@@ -64,6 +64,40 @@ bool Neighbor::IsStateValidOrAttaching(void) const
     return rval;
 }
 
+bool Neighbor::MatchesFilter(StateFilter aFilter) const
+{
+    bool matches = false;
+
+    switch (aFilter)
+    {
+    case kInStateValid:
+        matches = IsStateValid();
+        break;
+
+    case kInStateValidOrRestoring:
+        matches = IsStateValidOrRestoring();
+        break;
+
+    case kInStateChildIdRequest:
+        matches = IsStateChildIdRequest();
+        break;
+
+    case kInStateValidOrAttaching:
+        matches = IsStateValidOrAttaching();
+        break;
+
+    case kInStateAnyExceptInvalid:
+        matches = !IsStateInvalid();
+        break;
+
+    case kInStateAnyExceptValidOrRestoring:
+        matches = !IsStateValidOrRestoring();
+        break;
+    }
+
+    return matches;
+}
+
 void Neighbor::GenerateChallenge(void)
 {
     Random::Crypto::FillBuffer(mValidPending.mPending.mChallenge, sizeof(mValidPending.mPending.mChallenge));

src/core/thread/topology.hpp

@@ -75,6 +75,22 @@ public:
         kStateValid,              ///< Link is valid
     };
 
+    /**
+     * This enumeration defines state filters used for finding a neighbor or iterating through the child/neighbor table.
+     *
+     * Each filter definition accepts a subset of `State` values.
+     *
+     */
+    enum StateFilter
+    {
+        kInStateValid,                     ///< Accept child only in `kStateValid`.
+        kInStateValidOrRestoring,          ///< Accept child with `IsStateValidOrRestoring()` being `true`.
+        kInStateChildIdRequest,            ///< Accept child only in `Child:kStateChildIdRequest`.
+        kInStateValidOrAttaching,          ///< Accept child with `IsStateValidOrAttaching()` being `true`.
+        kInStateAnyExceptInvalid,          ///< Accept child in any state except `kStateInvalid`.
+        kInStateAnyExceptValidOrRestoring, ///< Accept child in any state except `IsStateValidOrRestoring()`.
+    };
+
     /**
      * This method returns the current state.
      *
@@ -168,6 +184,16 @@ public:
      */
     bool IsStateValidOrAttaching(void) const;
 
+    /**
+     * This method indicates whether neighbor state matches a given state filter.
+     *
+     * @param[in] aFilter   A state filter (`StateFilter` enumeration) to match against.
+     *
+     * @returns TRUE if the neighbor state matches the filter, FALSE otherwise.
+     *
+     */
+    bool MatchesFilter(StateFilter aFilter) const;
+
     /**
      * This method gets the device mode flags.
      *

src/core/utils/child_supervision.cpp

@@ -120,7 +120,7 @@ void ChildSupervisor::HandleTimer(void)
 {
     VerifyOrExit(mSupervisionInterval != 0);
 
-    for (ChildTable::Iterator iter(GetInstance(), ChildTable::kInStateValid); !iter.IsDone(); iter++)
+    for (ChildTable::Iterator iter(GetInstance(), Child::kInStateValid); !iter.IsDone(); iter++)
     {
         Child &child = *iter.GetChild();
 
@@ -147,7 +147,7 @@ void ChildSupervisor::CheckState(void)
     // "valid" child in the child table.
 
     shouldRun = ((mSupervisionInterval != 0) && (Get<Mle::MleRouter>().GetRole() != OT_DEVICE_ROLE_DISABLED) &&
-                 Get<ChildTable>().HasChildren(ChildTable::kInStateValid));
+                 Get<ChildTable>().HasChildren(Child::kInStateValid));
 
     if (shouldRun && !mTimer.IsRunning())
     {

tests/unit/test_child_table.cpp

@@ -51,12 +51,12 @@ struct TestChild
     otExtAddress mExtAddress;
 };
 
-const ChildTable::StateFilter kAllFilters[] = {
-    ChildTable::kInStateValid,
-    ChildTable::kInStateValidOrRestoring,
-    ChildTable::kInStateChildIdRequest,
-    ChildTable::kInStateValidOrAttaching,
-    ChildTable::kInStateAnyExceptInvalid,
+const Child::StateFilter kAllFilters[] = {
+    Child::kInStateValid,
+    Child::kInStateValidOrRestoring,
+    Child::kInStateChildIdRequest,
+    Child::kInStateValidOrAttaching,
+    Child::kInStateAnyExceptInvalid,
 };
 
 // Checks whether a `Child` matches the `TestChild` struct.
@@ -66,8 +66,8 @@ static bool ChildMatches(const Child &aChild, const TestChild &aTestChild)
            (aChild.GetExtAddress() == static_cast<const Mac::ExtAddress &>(aTestChild.mExtAddress));
 }
 
-// Checks whether a `Child::State` matches a `ChildTable::StateFilter`.
-static bool StateMatchesFilter(Child::State aState, ChildTable::StateFilter aFilter)
+// Checks whether a `Child::State` matches a `Child::StateFilter`.
+static bool StateMatchesFilter(Child::State aState, Child::StateFilter aFilter)
 {
     bool  rval = false;
     Child child;
@@ -76,27 +76,27 @@ static bool StateMatchesFilter(Child::State aState, ChildTable::StateFilter aFil
 
     switch (aFilter)
     {
-    case ChildTable::kInStateAnyExceptInvalid:
+    case Child::kInStateAnyExceptInvalid:
         rval = (aState != Child::kStateInvalid);
         break;
 
-    case ChildTable::kInStateValid:
+    case Child::kInStateValid:
         rval = (aState == Child::kStateValid);
         break;
 
-    case ChildTable::kInStateValidOrRestoring:
+    case Child::kInStateValidOrRestoring:
         rval = child.IsStateValidOrRestoring();
         break;
 
-    case ChildTable::kInStateChildIdRequest:
+    case Child::kInStateChildIdRequest:
         rval = (aState == Child::kStateChildIdRequest);
         break;
 
-    case ChildTable::kInStateValidOrAttaching:
+    case Child::kInStateValidOrAttaching:
         rval = child.IsStateValidOrAttaching();
         break;
 
-    case ChildTable::kInStateAnyExceptValidOrRestoring:
+    case Child::kInStateAnyExceptValidOrRestoring:
         rval = !child.IsStateValidOrRestoring();
         break;
     }
@@ -111,7 +111,7 @@ void VerifyChildTableContent(ChildTable &aTable, uint16_t aChildListLength, cons
 
     for (uint16_t k = 0; k < OT_ARRAY_LENGTH(kAllFilters); k++)
     {
-        ChildTable::StateFilter filter = kAllFilters[k];
+        Child::StateFilter filter = kAllFilters[k];
 
         // Verify that we can find all children from given list by rloc or extended address.
 
@@ -152,7 +152,7 @@ void VerifyChildTableContent(ChildTable &aTable, uint16_t aChildListLength, cons
 
             if (listIndex < aChildListLength)
             {
-                startingChild = aTable.FindChild(aChildList[listIndex].mRloc16, ChildTable::kInStateAnyExceptInvalid);
+                startingChild = aTable.FindChild(aChildList[listIndex].mRloc16, Child::kInStateAnyExceptInvalid);
                 VerifyOrQuit(startingChild != NULL, "FindChild() failed");
             }
 
@@ -316,7 +316,7 @@ void TestChildTable(void)
 
     for (uint16_t i = 0; i < OT_ARRAY_LENGTH(kAllFilters); i++)
     {
-        ChildTable::StateFilter filter = kAllFilters[i];
+        Child::StateFilter filter = kAllFilters[i];
 
         VerifyOrQuit(table->HasChildren(filter) == false, "HasChildren() failed after init");
         VerifyOrQuit(table->GetNumChildren(filter) == 0, "GetNumChildren() failed after init");