[netdata] support Extended TLVs in Commissioning Data sub-TLVs (#13594)

This commit enhances `NetworkData::Leader` handling of Commissioning
Data sub-TLVs to support MeshCoP regular and Extended TLVs:

- Define `CommissioningDataSubTlvInfo` and `FindCommissioningDataSubTlv()`
  to retrieve sub-TLVs, their value pointers, and lengths, correctly
  handling both standard and extended TLVs.
- Updates `ReadCommissioningDataUint16SubTlv`, `FindSteeringData`, and
  `ProcessCommissionerGetRequest` to use `CommissioningDataSubTlvInfo`.
- Removes the `FindInCommissioningData<SubTlvType>` template to prevent
  potential unsafe use.
- Introduces `Leader::UpdateBorderAgentRloc()` to safely update the
  Border Agent Locator sub-TLV in-place and increment the Network Data
  version (if the RLOC changed).
- Introduces `Leader::HasBorderAgentRloc()` to check for the presence
  of a valid Border Agent Locator sub-TLV without requiring dummy
  out-parameters at call sites.

src/core/meshcop/border_agent.cpp

@@ -535,10 +535,10 @@ Error Manager::EvictActiveCommissioner(void)
 {
     Error                   error = kErrorNone;
     uint16_t                sessionId;
-    uint16_t                baRloc16;
     OwnedPtr<Coap::Message> message;
 
-    SuccessOrExit(error = Get<NetworkData::Leader>().FindBorderAgentRloc(baRloc16));
+    VerifyOrExit(Get<NetworkData::Leader>().HasBorderAgentRloc(), error = kErrorNotFound);
+
     SuccessOrExit(error = Get<NetworkData::Leader>().FindCommissioningSessionId(sessionId));
 
     message.Reset(Get<Tmf::Agent>().AllocateAndInitPriorityConfirmablePostMessage(kUriLeaderKeepAlive));

src/core/meshcop/border_agent_admitter.cpp

@@ -571,7 +571,7 @@ void Admitter::CommissionerPetitioner::SendPetitionIfNoOtherCommissioner(void)
 
     OT_ASSERT(mState == kToPetition || mState == kRejected);
 
-    if (Get<NetworkData::Leader>().FindInCommissioningData<BorderAgentLocatorTlv>() != nullptr)
+    if (Get<NetworkData::Leader>().HasBorderAgentRloc())
     {
         SetState(kRejected);
         ExitNow();

src/core/meshcop/meshcop_leader.cpp

@@ -112,10 +112,9 @@ exit:
 
 template <> void Leader::HandleTmf<kUriLeaderKeepAlive>(Coap::Msg &aMsg)
 {
-    uint8_t                state;
+    uint8_t         state;
-    uint16_t               sessionId;
+    uint16_t        sessionId;
-    BorderAgentLocatorTlv *borderAgentLocator;
+    StateTlv::State responseState;
-    StateTlv::State        responseState;
 
     LogInfo("Received %s", UriToString<kUriLeaderKeepAlive>());
 
@@ -125,9 +124,7 @@ template <> void Leader::HandleTmf<kUriLeaderKeepAlive>(Coap::Msg &aMsg)
 
     SuccessOrExit(Tlv::Find<CommissionerSessionIdTlv>(aMsg.mMessage, sessionId));
 
-    borderAgentLocator = Get<NetworkData::Leader>().FindInCommissioningData<BorderAgentLocatorTlv>();
+    if (!Get<NetworkData::Leader>().HasBorderAgentRloc() || (sessionId != mSessionId))
-
-    if ((borderAgentLocator == nullptr) || (sessionId != mSessionId))
     {
         responseState = StateTlv::kReject;
     }
@@ -138,13 +135,7 @@ template <> void Leader::HandleTmf<kUriLeaderKeepAlive>(Coap::Msg &aMsg)
     }
     else
     {
-        uint16_t rloc = aMsg.mMessageInfo.GetPeerAddr().GetIid().GetLocator();
+        Get<NetworkData::Leader>().UpdateBorderAgentRloc(aMsg.mMessageInfo.GetPeerAddr().GetIid().GetLocator());
-
-        if (borderAgentLocator->GetBorderAgentLocator() != rloc)
-        {
-            borderAgentLocator->SetBorderAgentLocator(rloc);
-            Get<NetworkData::Leader>().IncrementVersion();
-        }
 
         responseState = StateTlv::kAccept;
         mTimer.Start(kLeaderPetitionTimeout);

src/core/thread/energy_scan_server.cpp

@@ -174,10 +174,8 @@ exit:
 
 void EnergyScanServer::HandleNotifierEvents(Events aEvents)
 {
-    uint16_t borderAgentRloc;
-
     if (aEvents.Contains(kEventThreadNetdataChanged) && (mReportMessage != nullptr) &&
-        Get<NetworkData::Leader>().FindBorderAgentRloc(borderAgentRloc) != kErrorNone)
+        !Get<NetworkData::Leader>().HasBorderAgentRloc())
     {
         Stop();
     }

src/core/thread/network_data_leader.cpp

@@ -505,26 +505,36 @@ const CommissioningDataTlv *Leader::FindCommissioningData(void) const
     return NetworkDataTlv::Find<CommissioningDataTlv>(GetTlvsStart(), GetTlvsEnd());
 }
 
-const MeshCoP::Tlv *Leader::FindCommissioningDataSubTlv(uint8_t aType) const
+Error Leader::FindCommissioningDataSubTlv(uint8_t aType, CommissioningDataSubTlvInfo &aSubTlvInfo) const
 {
-    const MeshCoP::Tlv   *subTlv  = nullptr;
+    Error                 error   = kErrorNotFound;
     const NetworkDataTlv *dataTlv = FindCommissioningData();
+    const MeshCoP::Tlv   *subTlv;
 
     VerifyOrExit(dataTlv != nullptr);
+
     subTlv = As<MeshCoP::Tlv>(Tlv::FindTlv(dataTlv->GetValue(), dataTlv->GetLength(), aType));
+    VerifyOrExit(subTlv != nullptr);
+
+    aSubTlvInfo.mTlv    = subTlv;
+    aSubTlvInfo.mValue  = subTlv->GetValue();
+    aSubTlvInfo.mLength = subTlv->IsExtended() ? As<ExtendedTlv>(subTlv)->GetLength() : subTlv->GetLength();
+
+    error = kErrorNone;
 
 exit:
-    return subTlv;
+    return error;
 }
 
 Error Leader::ReadCommissioningDataUint16SubTlv(MeshCoP::Tlv::Type aType, uint16_t &aValue) const
 {
-    Error               error  = kErrorNone;
+    Error                       error;
-    const MeshCoP::Tlv *subTlv = FindCommissioningDataSubTlv(aType);
+    CommissioningDataSubTlvInfo subTlvInfo;
 
-    VerifyOrExit(subTlv != nullptr, error = kErrorNotFound);
+    SuccessOrExit(error = FindCommissioningDataSubTlv(aType, subTlvInfo));
-    VerifyOrExit(subTlv->GetLength() >= sizeof(uint16_t), error = kErrorParse);
+
-    aValue = BigEndian::ReadUint16(subTlv->GetValue());
+    VerifyOrExit(subTlvInfo.mLength >= sizeof(uint16_t), error = kErrorParse);
+    aValue = BigEndian::ReadUint16(subTlvInfo.mValue);
 
 exit:
     return error;
@@ -583,16 +593,14 @@ Coap::Message *Leader::ProcessCommissionerGetRequest(const Coap::Message &aMessa
 
         while (!offsetRange.IsEmpty())
         {
-            uint8_t             type;
+            uint8_t                     type;
-            const MeshCoP::Tlv *subTlv;
+            CommissioningDataSubTlvInfo subTlvInfo;
 
             IgnoreError(aMessage.ReadAndAdvance(offsetRange, type));
 
-            subTlv = FindCommissioningDataSubTlv(type);
+            if (FindCommissioningDataSubTlv(type, subTlvInfo) == kErrorNone)
-
-            if (subTlv != nullptr)
             {
-                SuccessOrExit(error = subTlv->AppendTo(*response));
+                SuccessOrExit(error = subTlvInfo.mTlv->AppendTo(*response));
             }
         }
     }
@@ -618,6 +626,13 @@ Error Leader::FindBorderAgentRloc(uint16_t &aRloc16) const
     return ReadCommissioningDataUint16SubTlv(MeshCoP::Tlv::kBorderAgentLocator, aRloc16);
 }
 
+bool Leader::HasBorderAgentRloc(void) const
+{
+    uint16_t rloc16;
+
+    return (FindBorderAgentRloc(rloc16) == kErrorNone);
+}
+
 Error Leader::FindCommissioningSessionId(uint16_t &aSessionId) const
 {
     return ReadCommissioningDataUint16SubTlv(MeshCoP::Tlv::kCommissionerSessionId, aSessionId);
@@ -630,11 +645,14 @@ Error Leader::FindJoinerUdpPort(uint16_t &aPort) const
 
 Error Leader::FindSteeringData(MeshCoP::SteeringData &aSteeringData) const
 {
-    Error                           error           = kErrorNone;
+    Error                       error = kErrorNotFound;
-    const MeshCoP::SteeringDataTlv *steeringDataTlv = FindInCommissioningData<MeshCoP::SteeringDataTlv>();
+    CommissioningDataSubTlvInfo subTlvInfo;
+    uint16_t                    steeringDataLength;
 
-    VerifyOrExit(steeringDataTlv != nullptr, error = kErrorNotFound);
+    SuccessOrExit(FindCommissioningDataSubTlv(MeshCoP::Tlv::kSteeringData, subTlvInfo));
-    error = steeringDataTlv->CopyTo(aSteeringData);
+
+    steeringDataLength = Min<uint16_t>(subTlvInfo.mLength, MeshCoP::SteeringData::kMaxLength);
+    error              = aSteeringData.Init(static_cast<uint8_t>(steeringDataLength), subTlvInfo.mValue);
 
 exit:
     return error;

src/core/thread/network_data_leader.hpp

@@ -186,30 +186,6 @@ public:
      */
     Coap::Message *ProcessCommissionerGetRequest(const Coap::Message &aMessage) const;
 
-    /**
-     * Searches for given sub-TLV in Commissioning Data TLV.
-     *
-     * @tparam SubTlvType    The sub-TLV type to search for.
-     *
-     * @returns A pointer to the Commissioning Data Sub-TLV or `nullptr` if no such sub-TLV exists.
-     */
-    template <typename SubTlvType> const SubTlvType *FindInCommissioningData(void) const
-    {
-        return As<SubTlvType>(FindCommissioningDataSubTlv(SubTlvType::kType));
-    }
-
-    /**
-     * Searches for given sub-TLV in Commissioning Data TLV.
-     *
-     * @tparam SubTlvType    The sub-TLV type to search for.
-     *
-     * @returns A pointer to the Commissioning Data Sub-TLV or `nullptr` if no such sub-TLV exists.
-     */
-    template <typename SubTlvType> SubTlvType *FindInCommissioningData(void)
-    {
-        return As<SubTlvType>(FindCommissioningDataSubTlv(SubTlvType::kType));
-    }
-
     /**
      * Finds and reads the Commissioning Session ID in Commissioning Data TLV.
      *
@@ -232,6 +208,14 @@ public:
      */
     Error FindBorderAgentRloc(uint16_t &aRloc16) const;
 
+    /**
+     * Indicates whether the Commissioning Data contains a valid Border Agent Locator sub-TLV.
+     *
+     * @retval TRUE   The Commissioning Data contains a valid Border Agent Locator sub-TLV.
+     * @retval FALSE  The Commissioning Data does not contain a valid Border Agent Locator sub-TLV.
+     */
+    bool HasBorderAgentRloc(void) const;
+
     /**
      * Finds and reads the Joiner UDP Port in Commissioning Data TLV.
      *
@@ -356,6 +340,18 @@ public:
      */
     void IncrementVersionAndStableVersion(void);
 
+    /**
+     * Updates the Border Agent Locator sub-TLV in the Commissioning Data.
+     *
+     * If the Border Agent Locator sub-TLV is present in the Commissioning Data and its value differs from @p aRloc16,
+     * this method updates its value in-place and increments the Thread Network Data version. If the sub-TLV is not
+     * present, or if its value already matches @p aRloc16, no changes are made and the Network Data version is not
+     * incremented.
+     *
+     * @param[in] aRloc16  The new Border Agent RLOC16 value.
+     */
+    void UpdateBorderAgentRloc(uint16_t aRloc16);
+
     /**
      * Performs anycast ALOC route lookup using the Network Data.
      *
@@ -432,6 +428,13 @@ private:
 
     typedef bool (&EntryChecker)(const BorderRouterEntry &aEntry);
 
+    struct CommissioningDataSubTlvInfo
+    {
+        const Tlv     *mTlv;
+        const uint8_t *mValue;
+        uint16_t       mLength;
+    };
+
     const PrefixTlv *FindNextMatchingPrefixTlv(const Ip6::Address &aAddress, const PrefixTlv *aPrevTlv) const;
     const PrefixTlv *FindPrefixTlvForContextId(uint8_t aContextId, const ContextTlv *&aContextTlv) const;
 
@@ -453,11 +456,7 @@ private:
     void  SignalNetDataChanged(void);
     const CommissioningDataTlv *FindCommissioningData(void) const;
     CommissioningDataTlv *FindCommissioningData(void) { return AsNonConst(AsConst(this)->FindCommissioningData()); }
-    const MeshCoP::Tlv   *FindCommissioningDataSubTlv(uint8_t aType) const;
+    Error                 FindCommissioningDataSubTlv(uint8_t aType, CommissioningDataSubTlvInfo &aSubTlvInfo) const;
-    MeshCoP::Tlv         *FindCommissioningDataSubTlv(uint8_t aType)
-    {
-        return AsNonConst(AsConst(this)->FindCommissioningDataSubTlv(aType));
-    }
 
 #if OPENTHREAD_FTD
     static constexpr uint32_t kMaxNetDataSyncWait = 60 * 1000; // Maximum time to wait for netdata sync in msec.

src/core/thread/network_data_leader_ftd.cpp

@@ -99,6 +99,22 @@ exit:
     return;
 }
 
+void Leader::UpdateBorderAgentRloc(uint16_t aRloc16)
+{
+    CommissioningDataSubTlvInfo subTlvInfo;
+
+    SuccessOrExit(FindCommissioningDataSubTlv(MeshCoP::Tlv::kBorderAgentLocator, subTlvInfo));
+
+    VerifyOrExit(subTlvInfo.mLength >= sizeof(uint16_t));
+    VerifyOrExit(BigEndian::ReadUint16(subTlvInfo.mValue) != aRloc16);
+    BigEndian::WriteUint16(aRloc16, AsNonConst(subTlvInfo.mValue));
+
+    IncrementVersion();
+
+exit:
+    return;
+}
+
 Error Leader::AnycastLookup(uint16_t aAloc16, uint16_t &aRloc16) const
 {
     Error error = kErrorNone;
@@ -1285,7 +1301,6 @@ void Leader::HandleNetworkDataRestoredAfterReset(void)
     const PrefixTlv *prefix;
     TlvIterator      tlvIterator(GetTlvsStart(), GetTlvsEnd());
     ChangedFlags     flags;
-    uint16_t         rloc16;
     uint16_t         sessionId;
     Rlocs            rlocs;
 
@@ -1339,7 +1354,7 @@ void Leader::HandleNetworkDataRestoredAfterReset(void)
         Get<MeshCoP::Leader>().SetSessionId(sessionId);
     }
 
-    if (FindBorderAgentRloc(rloc16) == kErrorNone)
+    if (HasBorderAgentRloc())
     {
         Get<MeshCoP::Leader>().SetEmptyCommissionerData();
     }

tests/nexus/test_border_admitter.cpp

@@ -721,7 +721,7 @@ void TestBorderAdmitterEnrollerInteraction(void)
     VerifyOrQuit(admitter.Get<Admitter>().IsPrimeAdmitter());
     VerifyOrQuit(!admitter.Get<Admitter>().IsActiveCommissioner());
 
-    VerifyOrQuit(admitter.Get<NetworkData::Leader>().FindBorderAgentRloc(rloc16) == kErrorNotFound);
+    VerifyOrQuit(!admitter.Get<NetworkData::Leader>().HasBorderAgentRloc());
 
     nexus.AdvanceTime(10 * Time::kOneSecondInMsec);
 
@@ -933,7 +933,7 @@ void TestBorderAdmitterEnrollerInteraction(void)
     VerifyOrQuit(admitter.Get<Admitter>().IsPrimeAdmitter());
     VerifyOrQuit(!admitter.Get<Admitter>().IsActiveCommissioner());
 
-    VerifyOrQuit(admitter.Get<NetworkData::Leader>().FindBorderAgentRloc(rloc16) == kErrorNotFound);
+    VerifyOrQuit(!admitter.Get<NetworkData::Leader>().HasBorderAgentRloc());
 
     // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     Log("Re-establish DTLS session");