[border-agent] add vendor name and model to advertised TXT data (#12578)

This commit updates `BorderAgent` to parse the provided extra vendor
TXT data (`otBorderAgentSetVendorTxtData()`) to check if the vendor
name (`vn`) and model (`mn`) keys are already present. If they are
absent, it would use and encode the values from `VendorInfo` into the
advertised TXT data. This harmonizes the use of `VendorInfo` values
across various modules, network diagnostics, and the `BorderAgent`
TXT data.

Note that this change only impacts the system when
`OPENTHREAD_CONFIG_BORDER_AGENT_MESHCOP_SERVICE_ENABLE` is enabled,
meaning the Border Agent itself directly manages the registration and
updating of the mDNS MeshCoP service.

The generated TXT data from `otBorderAgentGetMeshCoPServiceTxtData()`
remains unchanged. This API is intended for use cases where the
next-layer code manages the publishing of the mDNS MeshCoP service,
and as documented, the TXT data from this API does not include any
vendor-specific information.

This commit updates `test_border_agent` to validate the newly
added behavior.

src/core/common/heap_data.cpp

@@ -82,6 +82,13 @@ void Data::TakeFrom(Data &&aData)
     }
 }
 
+void Data::TakeFrom(uint8_t *&aHeapAllocatedBuffer, uint16_t aLength)
+{
+    Free();
+    mData.Init(aHeapAllocatedBuffer, aLength);
+    aHeapAllocatedBuffer = nullptr;
+}
+
 bool Data::Matches(const uint8_t *aBuffer, uint16_t aLength) const
 {
     bool matches = false;

src/core/common/heap_data.hpp

@@ -140,6 +140,19 @@ public:
      */
     void TakeFrom(Data &&aData);
 
+    /**
+     * Sets the `Heap::Data` by taking ownership of a given heap-allocated buffer.
+     *
+     * After this call, the `Heap::Data` will take ownership of the buffer and free it when done.  The
+     * @p aHeapAllocatedBuffer pointer is set to `nullptr` to ensure the caller does not retain a pointer to the
+     * transferred buffer.
+     *
+     * @param[in,out] aHeapAllocatedBuffer  A reference to a pointer to a heap-allocated buffer.
+     *                                      On exit, it is set to `nullptr`.
+     * @param[in]     aLength               The length of the buffer (number of bytes).
+     */
+    void TakeFrom(uint8_t *&aHeapAllocatedBuffer, uint16_t aLength);
+
     /**
      * Casts the `Heap::Data` to an rvalue reference.
      *

src/core/meshcop/border_agent.cpp

@@ -432,38 +432,19 @@ void Manager::ConstrcutServiceName(const char *aBaseName, Dns::Name::LabelBuffer
 void Manager::RegisterService(void)
 {
     Dnssd::Service service;
-    uint16_t       vendorDataLength;
-    uint8_t       *txtDataBuffer;
-    uint16_t       txtDataBufferSize;
-    uint16_t       txtDataLength;
+    Heap::Data     txtData;
 
     VerifyOrExit(IsEnabled());
     VerifyOrExit(Get<Dnssd>().IsReady());
 
-    // Allocate a large enough buffer to fit both the TXT data
-    // generated by Border Agent itself and the vendor extra
-    // TXT data. The vendor TXT Data is appended at the
-    // end.
-
-    vendorDataLength  = Get<TxtData>().GetVendorData().GetLength();
-    txtDataBufferSize = kTxtDataMaxSize + vendorDataLength;
-    txtDataBuffer     = reinterpret_cast<uint8_t *>(Heap::CAlloc(txtDataBufferSize, sizeof(uint8_t)));
-    OT_ASSERT(txtDataBuffer != nullptr);
-
-    SuccessOrAssert(Get<TxtData>().Prepare(txtDataBuffer, txtDataBufferSize, txtDataLength));
-
-    if (vendorDataLength != 0)
-    {
-        Get<TxtData>().GetVendorData().CopyBytesTo(txtDataBuffer + txtDataLength);
-        txtDataLength += vendorDataLength;
-    }
+    Get<TxtData>().PrepareWithVendorData(txtData);
 
     service.Clear();
     service.mServiceInstance = GetServiceName();
     service.mServiceType     = kServiceType;
     service.mPort            = IsRunning() ? GetUdpPort() : kDummyUdpPort;
-    service.mTxtData         = txtDataBuffer;
-    service.mTxtDataLength   = txtDataLength;
+    service.mTxtData         = txtData.GetBytes();
+    service.mTxtDataLength   = txtData.GetLength();
 
 #if OPENTHREAD_CONFIG_BORDER_AGENT_ADMITTER_ENABLE
     if (Get<Admitter>().IsPrimeAdmitter())
@@ -475,8 +456,6 @@ void Manager::RegisterService(void)
 
     Get<Dnssd>().RegisterService(service, /* aRequestId */ 0, /* aCallback */ nullptr);
 
-    Heap::Free(txtDataBuffer);
-
 exit:
     return;
 }

src/core/meshcop/border_agent.hpp

@@ -264,7 +264,6 @@ public:
 private:
     static constexpr uint16_t kUdpPort          = OPENTHREAD_CONFIG_BORDER_AGENT_UDP_PORT;
     static constexpr uint32_t kKeepAliveTimeout = 50 * 1000; // Timeout to reject a commissioner (in msec)
-    static constexpr uint16_t kTxtDataMaxSize   = OT_BORDER_AGENT_MESHCOP_SERVICE_TXT_DATA_MAX_LENGTH;
 
 #if OPENTHREAD_CONFIG_BORDER_AGENT_MESHCOP_SERVICE_ENABLE
     static constexpr uint16_t kDummyUdpPort          = 49152;

src/core/meshcop/border_agent_txt_data.cpp

@@ -57,22 +57,28 @@ const char TxtData::Key::kBbrSeqNum[]       = "sq";
 const char TxtData::Key::kBbrPort[]         = "bb";
 const char TxtData::Key::kOmrPrefix[]       = "omr";
 const char TxtData::Key::kExtAddress[]      = "xa";
-#if OPENTHREAD_CONFIG_BORDER_AGENT_TXT_DATA_PARSER_ENABLE
-const char TxtData::Key::kVendorName[] = "vn";
-const char TxtData::Key::kModelName[]  = "mn";
-#endif
+const char TxtData::Key::kVendorName[]      = "vn";
+const char TxtData::Key::kModelName[]       = "mn";
 
 TxtData::TxtData(Instance &aInstance)
     : InstanceLocator(aInstance)
 #if OPENTHREAD_CONFIG_BORDER_AGENT_ENABLE
     , mChangedTask(aInstance)
 #endif
+#if OPENTHREAD_CONFIG_BORDER_AGENT_MESHCOP_SERVICE_ENABLE
+    , mShouldAddVendorName(true)
+    , mShouldAddVendorModel(true)
+#endif
 {
 }
 
 #if OPENTHREAD_CONFIG_BORDER_AGENT_ENABLE
 
-Error TxtData::Prepare(uint8_t *aBuffer, uint16_t aBufferSize, uint16_t &aLength)
+Error TxtData::Prepare(uint8_t  *aBuffer,
+                       uint16_t  aBufferSize,
+                       uint16_t &aLength,
+                       bool      aAddVendorName,
+                       bool      aAddVendorModel)
 {
     Error                  error = kErrorNone;
     Dns::TxtDataEncoder    encoder(aBuffer, aBufferSize);
@@ -152,6 +158,16 @@ Error TxtData::Prepare(uint8_t *aBuffer, uint16_t aBufferSize, uint16_t &aLength
     }
 #endif
 
+    if (aAddVendorName)
+    {
+        SuccessOrExit(error = encoder.AppendStringEntry(Key::kVendorName, Get<VendorInfo>().GetName()));
+    }
+
+    if (aAddVendorModel)
+    {
+        SuccessOrExit(error = encoder.AppendStringEntry(Key::kModelName, Get<VendorInfo>().GetModel()));
+    }
+
     aLength = encoder.GetLength();
 
 exit:
@@ -160,7 +176,8 @@ exit:
 
 Error TxtData::Prepare(ServiceTxtData &aTxtData)
 {
-    return Prepare(aTxtData.mData, sizeof(aTxtData.mData), aTxtData.mLength);
+    return Prepare(aTxtData.mData, sizeof(aTxtData.mData), aTxtData.mLength, /* aAddVendorName */ false,
+                   /* aAddVendorModel */ false);
 }
 
 void TxtData::SetChangedCallback(ChangedCallback aCallback, void *aContext)
@@ -194,18 +211,98 @@ exit:
 
 #if OPENTHREAD_CONFIG_BORDER_AGENT_MESHCOP_SERVICE_ENABLE
 
+void TxtData::PrepareWithVendorData(Heap::Data &aTxtData)
+{
+    uint16_t size;
+    uint16_t length;
+    uint8_t *buffer;
+
+    // Allocate a large enough buffer to fit both the base TXT data
+    // generated by the Border Agent and the vendor extra TXT data.
+    // The vendor TXT data is appended at the end. If `mVendorData`
+    // does not contain vendor name or model entries, they are
+    // populated from `VendorInfo` and room is allocated for them.
+
+    size = kMaxSizeNoVendorData + mVendorData.GetLength();
+
+    if (mShouldAddVendorName)
+    {
+        size += Tlv::kMaxVendorNameLength + sizeof(Key::kVendorName) + sizeof('=');
+    }
+
+    if (mShouldAddVendorModel)
+    {
+        size += Tlv::kMaxVendorModelLength + sizeof(Key::kModelName) + sizeof('=');
+    }
+
+    buffer = reinterpret_cast<uint8_t *>(Heap::CAlloc(size, sizeof(uint8_t)));
+
+    OT_ASSERT(buffer != nullptr);
+
+    SuccessOrAssert(Prepare(buffer, size, length, mShouldAddVendorName, mShouldAddVendorModel));
+
+    if (mVendorData.GetLength() != 0)
+    {
+        mVendorData.CopyBytesTo(buffer + length);
+        length += mVendorData.GetLength();
+    }
+
+    aTxtData.TakeFrom(buffer, length);
+}
+
 void TxtData::SetVendorData(const uint8_t *aVendorData, uint16_t aVendorDataLength)
 {
+    Dns::TxtEntry           entry;
+    Dns::TxtEntry::Iterator iterator;
+
     VerifyOrExit(!mVendorData.Matches(aVendorData, aVendorDataLength));
 
     SuccessOrAssert(mVendorData.SetFrom(aVendorData, aVendorDataLength));
+
+    // Check whether the provided `mVendorData` contains vendor name
+    // or model entries. If not present, the values from `VendorInfo`
+    // will be used and encoded in the TXT data.
+
+    mShouldAddVendorName  = true;
+    mShouldAddVendorModel = true;
+
+    iterator.Init(mVendorData.GetBytes(), mVendorData.GetLength());
+
+    while (iterator.GetNextEntry(entry) == kErrorNone)
+    {
+        if (entry.MatchesKey(Key::kVendorName))
+        {
+            mShouldAddVendorName = false;
+        }
+        else if (entry.MatchesKey(Key::kModelName))
+        {
+            mShouldAddVendorModel = false;
+        }
+    }
+
     Refresh();
 
 exit:
     return;
 }
 
-#endif
+void TxtData::HandleVendorNameChange(void)
+{
+    if (mShouldAddVendorName)
+    {
+        Refresh();
+    }
+}
+
+void TxtData::HandleVendorModelChange(void)
+{
+    if (mShouldAddVendorModel)
+    {
+        Refresh();
+    }
+}
+
+#endif // OPENTHREAD_CONFIG_BORDER_AGENT_MESHCOP_SERVICE_ENABLE
 
 uint32_t TxtData::StateBitmap::Determine(Instance &aInstance)
 {

src/core/meshcop/border_agent_txt_data.hpp

@@ -51,6 +51,7 @@
 #include "common/type_traits.hpp"
 #include "net/dns_types.hpp"
 #include "net/ip6_address.hpp"
+#include "thread/vendor_info.hpp"
 
 namespace ot {
 namespace MeshCoP {
@@ -61,6 +62,7 @@ namespace BorderAgent {
 class TxtData : public InstanceLocator
 {
     friend class ot::Notifier;
+    friend class ot::VendorInfo;
 
 public:
     typedef otBorderAgentConnMode      ConnMode;      ///< Connection Mode in a Border Agent State Bitmap.
@@ -206,18 +208,6 @@ public:
     typedef otBorderAgentMeshCoPServiceTxtData         ServiceTxtData;  ///< Service TXT Data.
     typedef otBorderAgentMeshCoPServiceChangedCallback ChangedCallback; ///< Service TXT Data changed callback.
 
-    /**
-     * Prepares the MeshCoP service TXT data.
-     *
-     * @param[out]    aBuffer        A pointer to a buffer to store the TXT data.
-     * @param[in]     aBufferSize    The size of @p aBuffer.
-     * @param[out]    aLength        On exit, the length of the prepared TXT data.
-     *
-     * @retval kErrorNone      Successfully prepared the TXT data.
-     * @retval kErrorNoBufs    The @p aBufferSize is too small.
-     */
-    Error Prepare(uint8_t *aBuffer, uint16_t aBufferSize, uint16_t &aLength);
-
     /**
      * Prepares the MeshCoP service TXT data.
      *
@@ -253,11 +243,15 @@ public:
 
 #if OPENTHREAD_CONFIG_BORDER_AGENT_MESHCOP_SERVICE_ENABLE
     /**
-     * Returns the vendor TXT data.
+     * Prepares the MeshCoP service TXT data including the vendor extra TXT data.
      *
-     * @returns The vendor TXT data.
+     * The TXT data generated by the Border Agent itself is appended with the vendor extra TXT data (if any).
+     * If the vendor extra TXT data does not include vendor name or model entries, they are added automatically
+     * using the values from `VendorInfo`.
+     *
+     * @param[out] aTxtData   A reference to a `Heap::Data` object to output the prepared TXT data.
      */
-    const Heap::Data &GetVendorData(void) const { return mVendorData; }
+    void PrepareWithVendorData(Heap::Data &aTxtData);
 
     /**
      * Sets the vendor extra TXT data to be included when the Border Agent advertises the mDNS `_meshcop._udp` service.
@@ -285,6 +279,8 @@ public:
 #endif // OPENTHREAD_CONFIG_BORDER_AGENT_ENABLE
 
 private:
+    static constexpr uint16_t kMaxSizeNoVendorData = OT_BORDER_AGENT_MESHCOP_SERVICE_TXT_DATA_MAX_LENGTH;
+
     static const char kRecordVersion[];
 
     struct Key
@@ -302,10 +298,8 @@ private:
         static const char kBbrPort[];
         static const char kOmrPrefix[];
         static const char kExtAddress[];
-#if OPENTHREAD_CONFIG_BORDER_AGENT_TXT_DATA_PARSER_ENABLE
         static const char kVendorName[];
         static const char kModelName[];
-#endif
     };
 
     struct StateBitmap
@@ -363,9 +357,14 @@ private:
 #endif
     };
 
+    Error Prepare(uint8_t *aBuffer, uint16_t aBufferSize, uint16_t &aLength, bool aAddVendorName, bool aAddVendorModel);
+
 #if OPENTHREAD_CONFIG_BORDER_AGENT_ENABLE
     // Callback from Notifier
     void HandleNotifierEvents(Events aEvents);
+    // Callbacks from VendorInfo
+    void HandleVendorNameChange(void);
+    void HandleVendorModelChange(void);
 
     void HandleChangedTask(void);
 
@@ -375,6 +374,8 @@ private:
     ChangedTask               mChangedTask;
 #if OPENTHREAD_CONFIG_BORDER_AGENT_MESHCOP_SERVICE_ENABLE
     Heap::Data mVendorData;
+    bool       mShouldAddVendorName;
+    bool       mShouldAddVendorModel;
 #endif
 #endif
 };

src/core/thread/vendor_info.cpp

@@ -69,7 +69,9 @@ VendorInfo::VendorInfo(Instance &aInstance)
 
 Error VendorInfo::SetName(const char *aName)
 {
-    Error error;
+    Error error = kErrorNone;
+
+    VerifyOrExit(!StringMatch(mName, (aName == nullptr) ? "" : aName));
 
 #if OPENTHREAD_CONFIG_REFERENCE_DEVICE_ENABLE
     VerifyOrExit(aName != nullptr && StringStartsWith(aName, kNamePrefix), error = kErrorInvalidArgs);
@@ -77,11 +79,29 @@ Error VendorInfo::SetName(const char *aName)
 
     SuccessOrExit(error = StringCopy(mName, aName, kStringCheckUtf8Encoding));
 
+#if OPENTHREAD_CONFIG_BORDER_AGENT_ENABLE && OPENTHREAD_CONFIG_BORDER_AGENT_MESHCOP_SERVICE_ENABLE
+    Get<MeshCoP::BorderAgent::TxtData>().HandleVendorNameChange();
+#endif
+
 exit:
     return error;
 }
 
-Error VendorInfo::SetModel(const char *aModel) { return StringCopy(mModel, aModel, kStringCheckUtf8Encoding); }
+Error VendorInfo::SetModel(const char *aModel)
+{
+    Error error = kErrorNone;
+
+    VerifyOrExit(!StringMatch(mModel, (aModel == nullptr) ? "" : aModel));
+
+    SuccessOrExit(error = StringCopy(mModel, aModel, kStringCheckUtf8Encoding));
+
+#if OPENTHREAD_CONFIG_BORDER_AGENT_ENABLE && OPENTHREAD_CONFIG_BORDER_AGENT_MESHCOP_SERVICE_ENABLE
+    Get<MeshCoP::BorderAgent::TxtData>().HandleVendorModelChange();
+#endif
+
+exit:
+    return error;
+}
 
 Error VendorInfo::SetSwVersion(const char *aSwVersion)
 {

tests/nexus/test_border_agent.cpp

@@ -1293,7 +1293,7 @@ struct TxtData
     uint16_t       mLength;
 };
 
-void ValidateMeshCoPTxtData(TxtData &aTxtData, Node &aNode)
+void ValidateMeshCoPTxtData(TxtData &aTxtData, Node &aNode, bool aExpectVendorInfo, const char *aVendorName = nullptr)
 {
     // State bitmap masks and field values
     static constexpr uint32_t kMaskConnectionMode           = 7 << 0;
@@ -1447,6 +1447,28 @@ void ValidateMeshCoPTxtData(TxtData &aTxtData, Node &aNode)
         VerifyOrQuit(!(stateBitmap & kFlagAdmitterSupported));
         VerifyOrQuit(!info.mStateBitmap.mAdmitterSupported);
     }
+
+    if (aExpectVendorInfo)
+    {
+        const char *expectedVendorName = (aVendorName != nullptr) ? aVendorName : aNode.Get<VendorInfo>().GetName();
+        const char *expectedModelName  = aNode.Get<VendorInfo>().GetModel();
+
+        aTxtData.ValidateKey("vn", expectedVendorName);
+        VerifyOrQuit(info.mHasVendorName);
+        VerifyOrQuit(StringMatch(info.mVendorName, expectedVendorName));
+
+        aTxtData.ValidateKey("mn", expectedModelName);
+        VerifyOrQuit(info.mHasModelName);
+        VerifyOrQuit(StringMatch(info.mModelName, expectedModelName));
+    }
+    else
+    {
+        VerifyOrQuit(!aTxtData.ContainsKey("vn"));
+        VerifyOrQuit(!info.mHasVendorName);
+
+        VerifyOrQuit(!aTxtData.ContainsKey("mn"));
+        VerifyOrQuit(!info.mHasModelName);
+    }
 }
 
 //----------------------------------------------------------------------------------------------------------------------
@@ -1466,7 +1488,7 @@ void ReadAndValidateMeshCoPTxtData(Node &aNode)
     SuccessOrQuit(aNode.Get<BaTxtData>().Prepare(serviceTxtData));
     txtData.Init(serviceTxtData.mData, serviceTxtData.mLength);
 
-    ValidateMeshCoPTxtData(txtData, aNode);
+    ValidateMeshCoPTxtData(txtData, aNode, /* aExpectVendorInfo */ false);
 }
 
 void TestBorderAgentTxtDataCallback(void)
@@ -1553,7 +1575,7 @@ void TestBorderAgentTxtDataCallback(void)
 
 static constexpr uint32_t kInfraIfIndex   = 1;
 static constexpr uint16_t kMaxEntries     = 5;
-static constexpr uint16_t kMaxTxtDataSize = 128;
+static constexpr uint16_t kMaxTxtDataSize = 400;
 
 typedef Dns::Name::Buffer DnsName;
 
@@ -1626,12 +1648,14 @@ void HandleTxtCallback(otInstance *aInstance, const Dns::Multicast::Core::TxtRes
     outcome->mTtl           = aResult->mTtl;
 }
 
-void ValidateRegisteredServiceData(Dns::Multicast::Core::Service &aService, Node &aNode)
+void ValidateRegisteredServiceData(Dns::Multicast::Core::Service &aService,
+                                   Node                          &aNode,
+                                   const char                    *aVendorName = nullptr)
 {
     TxtData txtData;
 
     txtData.Init(aService.mTxtData, aService.mTxtDataLength);
-    ValidateMeshCoPTxtData(txtData, aNode);
+    ValidateMeshCoPTxtData(txtData, aNode, /* aExpectVendorInfo */ true, aVendorName);
 }
 
 void TestBorderAgentServiceRegistration(void)
@@ -1749,7 +1773,7 @@ void TestBorderAgentServiceRegistration(void)
     VerifyOrQuit(sTxtOutcomes.GetLength() == 1);
     VerifyOrQuit(sTxtOutcomes[0].mTtl > 0);
     txtData.Init(sTxtOutcomes[0].mTxtData, sTxtOutcomes[0].mTxtDataLength);
-    ValidateMeshCoPTxtData(txtData, node0);
+    ValidateMeshCoPTxtData(txtData, node0, /* aExptecVendorInfo */ true);
 
     sBrowseOutcomes.Clear();
     sSrvOutcomes.Clear();
@@ -2086,11 +2110,10 @@ void TestBorderAgentServiceRegistration(void)
     VerifyOrQuit(service.mTtl > 0);
     VerifyOrQuit(service.mInfraIfIndex == kInfraIfIndex);
     VerifyOrQuit(entryState == OT_MDNS_ENTRY_STATE_REGISTERED);
-    ValidateRegisteredServiceData(service, node0);
+    ValidateRegisteredServiceData(service, node0, /* aExpectedVendorName */ "nexus");
 
     // Check that vendor TXT data is included at the end of
     // the registered service TXT data.
-    VerifyOrQuit(service.mTxtDataLength > txtDataLengthWithNoVendorData);
     VerifyOrQuit(service.mTxtDataLength > sizeof(kVendorTxtData));
     VerifyOrQuit(!memcmp(&service.mTxtData[service.mTxtDataLength - sizeof(kVendorTxtData)], kVendorTxtData,
                          sizeof(kVendorTxtData)));
@@ -2131,6 +2154,68 @@ void TestBorderAgentServiceRegistration(void)
     VerifyOrQuit(node0.Get<Dns::Multicast::Core>().GetNextService(*iterator, service, entryState) == kErrorNotFound);
 
     node0.Get<Dns::Multicast::Core>().FreeIterator(*iterator);
+
+    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+    Log("Change vendor name and validate that the registered mDNS service is updated accordingly");
+
+    SuccessOrQuit(node0.Get<VendorInfo>().SetName("RD:v"));
+    nexus.AdvanceTime(Time::kOneSecondInMsec);
+
+    iterator = node0.Get<Dns::Multicast::Core>().AllocateIterator();
+    VerifyOrQuit(iterator != nullptr);
+
+    SuccessOrQuit(node0.Get<Dns::Multicast::Core>().GetNextService(*iterator, service, entryState));
+    Log("  HostName: %s", service.mHostName);
+    Log("  ServiceInstance: %s", service.mServiceInstance);
+    Log("  ServiceType: %s", service.mServiceType);
+    Log("  Port: %u", service.mPort);
+    Log("  TTL: %lu", ToUlong(service.mTtl));
+
+    VerifyOrQuit(StringMatch(service.mServiceType, "_meshcop._udp"));
+    VerifyOrQuit(StringStartsWith(service.mServiceInstance, "OpenThreadAgent"));
+    VerifyOrQuit(StringStartsWith(service.mHostName, "ot"));
+    VerifyOrQuit(service.mSubTypeLabelsLength == 0);
+    VerifyOrQuit(service.mPort == node0.Get<MeshCoP::BorderAgent::Manager>().GetUdpPort());
+    VerifyOrQuit(service.mTtl > 0);
+    VerifyOrQuit(service.mInfraIfIndex == kInfraIfIndex);
+    VerifyOrQuit(entryState == OT_MDNS_ENTRY_STATE_REGISTERED);
+    ValidateRegisteredServiceData(service, node0);
+
+    // Check that there is no more registered mDNS service
+    VerifyOrQuit(node0.Get<Dns::Multicast::Core>().GetNextService(*iterator, service, entryState) == kErrorNotFound);
+
+    node0.Get<Dns::Multicast::Core>().FreeIterator(*iterator);
+
+    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+    Log("Change vendor model and validate that the registered mDNS service is updated accordingly");
+
+    SuccessOrQuit(node0.Get<VendorInfo>().SetModel("model"));
+    nexus.AdvanceTime(Time::kOneSecondInMsec);
+
+    iterator = node0.Get<Dns::Multicast::Core>().AllocateIterator();
+    VerifyOrQuit(iterator != nullptr);
+
+    SuccessOrQuit(node0.Get<Dns::Multicast::Core>().GetNextService(*iterator, service, entryState));
+    Log("  HostName: %s", service.mHostName);
+    Log("  ServiceInstance: %s", service.mServiceInstance);
+    Log("  ServiceType: %s", service.mServiceType);
+    Log("  Port: %u", service.mPort);
+    Log("  TTL: %lu", ToUlong(service.mTtl));
+
+    VerifyOrQuit(StringMatch(service.mServiceType, "_meshcop._udp"));
+    VerifyOrQuit(StringStartsWith(service.mServiceInstance, "OpenThreadAgent"));
+    VerifyOrQuit(StringStartsWith(service.mHostName, "ot"));
+    VerifyOrQuit(service.mSubTypeLabelsLength == 0);
+    VerifyOrQuit(service.mPort == node0.Get<MeshCoP::BorderAgent::Manager>().GetUdpPort());
+    VerifyOrQuit(service.mTtl > 0);
+    VerifyOrQuit(service.mInfraIfIndex == kInfraIfIndex);
+    VerifyOrQuit(entryState == OT_MDNS_ENTRY_STATE_REGISTERED);
+    ValidateRegisteredServiceData(service, node0);
+
+    // Check that there is no more registered mDNS service
+    VerifyOrQuit(node0.Get<Dns::Multicast::Core>().GetNextService(*iterator, service, entryState) == kErrorNotFound);
+
+    node0.Get<Dns::Multicast::Core>().FreeIterator(*iterator);
 }
 
 } // namespace Nexus