[dataset] relocate IsTlvValid() to Dataset (#10060)

This commit relocates `IsTlvValid()` to the `Dataset` class,
emphasizing its specificity for validating Dataset TLVs and not other
MeshCop TLVs.

src/core/meshcop/dataset.cpp

@@ -172,14 +172,64 @@ bool Dataset::IsValid(void) const
 
     for (const Tlv *cur = GetTlvsStart(); cur < end; cur = cur->GetNext())
     {
-        VerifyOrExit(!cur->IsExtended() && (cur + 1) <= end && cur->GetNext() <= end && Tlv::IsValid(*cur),
-                     rval = false);
+        VerifyOrExit(!cur->IsExtended() && (cur + 1) <= end && cur->GetNext() <= end && IsTlvValid(*cur), rval = false);
     }
 
 exit:
     return rval;
 }
 
+bool Dataset::IsTlvValid(const Tlv &aTlv)
+{
+    bool    isValid   = true;
+    uint8_t minLength = 0;
+
+    switch (aTlv.GetType())
+    {
+    case Tlv::kPanId:
+        minLength = sizeof(PanIdTlv::UintValueType);
+        break;
+    case Tlv::kExtendedPanId:
+        minLength = sizeof(ExtendedPanIdTlv::ValueType);
+        break;
+    case Tlv::kPskc:
+        minLength = sizeof(PskcTlv::ValueType);
+        break;
+    case Tlv::kNetworkKey:
+        minLength = sizeof(NetworkKeyTlv::ValueType);
+        break;
+    case Tlv::kMeshLocalPrefix:
+        minLength = sizeof(MeshLocalPrefixTlv::ValueType);
+        break;
+    case Tlv::kChannel:
+        VerifyOrExit(aTlv.GetLength() >= sizeof(ChannelTlvValue), isValid = false);
+        isValid = aTlv.ReadValueAs<ChannelTlv>().IsValid();
+        break;
+    case Tlv::kNetworkName:
+        isValid = As<NetworkNameTlv>(aTlv).IsValid();
+        break;
+
+    case Tlv::kSecurityPolicy:
+        isValid = As<SecurityPolicyTlv>(aTlv).IsValid();
+        break;
+
+    case Tlv::kChannelMask:
+        isValid = As<ChannelMaskTlv>(aTlv).IsValid();
+        break;
+
+    default:
+        break;
+    }
+
+    if (minLength > 0)
+    {
+        isValid = (aTlv.GetLength() >= minLength);
+    }
+
+exit:
+    return isValid;
+}
+
 const Tlv *Dataset::FindTlv(Tlv::Type aType) const { return As<Tlv>(Tlv::FindTlv(mTlvs, mLength, aType)); }
 
 void Dataset::ConvertTo(Info &aDatasetInfo) const

src/core/meshcop/dataset.hpp

@@ -252,6 +252,20 @@ public:
      */
     bool IsValid(void) const;
 
+    /**
+     * Validates the format and value of a given MeshCoP TLV used in Dataset.
+     *
+     * TLV types that can appear in an Active or Pending Operational Dataset are validated. Other TLV types including
+     * unknown TLV types are considered as valid.
+     *
+     * @param[in]  aTlv    The TLV to validate.
+     *
+     * @retval  TRUE       The TLV format and value is valid, or TLV type is unknown (not supported in Dataset).
+     * @retval  FALSE      The TLV format or value is invalid.
+     *
+     */
+    static bool IsTlvValid(const Tlv &aTlv);
+
     /**
      * Indicates whether or not a given TLV type is present in the Dataset.
      *

src/core/meshcop/dataset_manager_ftd.cpp

@@ -291,7 +291,7 @@ Error DatasetManager::DatasetTlv::ReadFromMessage(const Message &aMessage, uint1
     SuccessOrExit(error = aMessage.Read(aOffset, this, sizeof(Tlv)));
     VerifyOrExit(GetLength() <= Dataset::kMaxValueSize, error = kErrorParse);
     SuccessOrExit(error = aMessage.Read(aOffset + sizeof(Tlv), mValue, GetLength()));
-    VerifyOrExit(Tlv::IsValid(*this), error = kErrorParse);
+    VerifyOrExit(Dataset::IsTlvValid(*this), error = kErrorParse);
 
 exit:
     return error;

src/core/meshcop/meshcop_tlvs.cpp

@@ -43,57 +43,6 @@
 namespace ot {
 namespace MeshCoP {
 
-bool Tlv::IsValid(const Tlv &aTlv)
-{
-    bool    isValid   = true;
-    uint8_t minLength = 0;
-
-    switch (aTlv.GetType())
-    {
-    case Tlv::kPanId:
-        minLength = sizeof(PanIdTlv::UintValueType);
-        break;
-    case Tlv::kExtendedPanId:
-        minLength = sizeof(ExtendedPanIdTlv::ValueType);
-        break;
-    case Tlv::kPskc:
-        minLength = sizeof(PskcTlv::ValueType);
-        break;
-    case Tlv::kNetworkKey:
-        minLength = sizeof(NetworkKeyTlv::ValueType);
-        break;
-    case Tlv::kMeshLocalPrefix:
-        minLength = sizeof(MeshLocalPrefixTlv::ValueType);
-        break;
-    case Tlv::kChannel:
-        VerifyOrExit(aTlv.GetLength() >= sizeof(ChannelTlvValue), isValid = false);
-        isValid = aTlv.ReadValueAs<ChannelTlv>().IsValid();
-        break;
-    case Tlv::kNetworkName:
-        isValid = As<NetworkNameTlv>(aTlv).IsValid();
-        break;
-
-    case Tlv::kSecurityPolicy:
-        isValid = As<SecurityPolicyTlv>(aTlv).IsValid();
-        break;
-
-    case Tlv::kChannelMask:
-        isValid = As<ChannelMaskTlv>(aTlv).IsValid();
-        break;
-
-    default:
-        break;
-    }
-
-    if (minLength > 0)
-    {
-        isValid = (aTlv.GetLength() >= minLength);
-    }
-
-exit:
-    return isValid;
-}
-
 NameData NetworkNameTlv::GetNetworkName(void) const
 {
     uint8_t len = GetLength();

src/core/meshcop/meshcop_tlvs.hpp

@@ -160,16 +160,6 @@ public:
      */
     const Tlv *GetNext(void) const { return As<Tlv>(ot::Tlv::GetNext()); }
 
-    /**
-     * Indicates whether a TLV appears to be well-formed.
-     *
-     * @param[in]  aTlv  A reference to the TLV.
-     *
-     * @returns TRUE if the TLV appears to be well-formed, FALSE otherwise.
-     *
-     */
-    static bool IsValid(const Tlv &aTlv);
-
 } OT_TOOL_PACKED_END;
 
 /**