This commit adds the Thread Domain Name TLV (59) to the MLE Discovery…

… Response message. The TLV is only included if not equal to 'DefaultDomain', as per Thread 1.4 spec Section 8.4.4.1.1.2.

include/openthread/dataset.h

@@ -310,6 +310,7 @@ typedef enum otMeshcopTlvType
     OT_MESHCOP_TLV_PERIOD                   = 55,  ///< meshcop Period TLV
     OT_MESHCOP_TLV_SCAN_DURATION            = 56,  ///< meshcop Scan Duration TLV
     OT_MESHCOP_TLV_ENERGY_LIST              = 57,  ///< meshcop Energy List TLV
+    OT_MESHCOP_TLV_THREAD_DOMAIN_NAME       = 59,  ///< meshcop Thread Domain Name TLV
     OT_MESHCOP_TLV_DISCOVERYREQUEST         = 128, ///< meshcop Discovery Request TLV
     OT_MESHCOP_TLV_DISCOVERYRESPONSE        = 129, ///< meshcop Discovery Response TLV
     OT_MESHCOP_TLV_JOINERADVERTISEMENT      = 241, ///< meshcop Joiner Advertisement TLV

include/openthread/instance.h

@@ -53,7 +53,7 @@ extern "C" {
  * @note This number versions both OpenThread platform and user APIs.
  *
  */
-#define OPENTHREAD_API_VERSION (446)
+#define OPENTHREAD_API_VERSION (447)
 
 /**
  * @addtogroup api-instance

src/core/meshcop/meshcop_tlvs.hpp

@@ -111,6 +111,7 @@ class Tlv : public ot::Tlv
         kPeriod                  = OT_MESHCOP_TLV_PERIOD,                   ///< Period TLV
         kScanDuration            = OT_MESHCOP_TLV_SCAN_DURATION,            ///< Scan Duration TLV
         kEnergyList              = OT_MESHCOP_TLV_ENERGY_LIST,              ///< Energy List TLV
+        kThreadDomainName        = OT_MESHCOP_TLV_THREAD_DOMAIN_NAME,       ///< Thread Domain Name TLV
         kDiscoveryRequest        = OT_MESHCOP_TLV_DISCOVERYREQUEST,         ///< Discovery Request TLV
         kDiscoveryResponse       = OT_MESHCOP_TLV_DISCOVERYRESPONSE,        ///< Discovery Response TLV
         kJoinerAdvertisement     = OT_MESHCOP_TLV_JOINERADVERTISEMENT,      ///< Joiner Advertisement TLV
@@ -122,11 +123,12 @@ class Tlv : public ot::Tlv
      */
     static constexpr uint8_t kMaxProvisioningUrlLength = OT_PROVISIONING_URL_MAX_SIZE;
 
-    static constexpr uint8_t kMaxCommissionerIdLength  = 64; ///< Max length of Commissioner ID TLV.
-    static constexpr uint8_t kMaxVendorNameLength      = 32; ///< Max length of Vendor Name TLV.
-    static constexpr uint8_t kMaxVendorModelLength     = 32; ///< Max length of Vendor Model TLV.
-    static constexpr uint8_t kMaxVendorSwVersionLength = 16; ///< Max length of Vendor SW Version TLV.
-    static constexpr uint8_t kMaxVendorDataLength      = 64; ///< Max length of Vendor Data TLV.
+    static constexpr uint8_t kMaxCommissionerIdLength   = 64; ///< Max length of Commissioner ID TLV.
+    static constexpr uint8_t kMaxVendorNameLength       = 32; ///< Max length of Vendor Name TLV.
+    static constexpr uint8_t kMaxVendorModelLength      = 32; ///< Max length of Vendor Model TLV.
+    static constexpr uint8_t kMaxVendorSwVersionLength  = 16; ///< Max length of Vendor SW Version TLV.
+    static constexpr uint8_t kMaxVendorDataLength       = 64; ///< Max length of Vendor Data TLV.
+    static constexpr uint8_t kMaxThreadDomainNameLength = 16; ///< Max length of Thread Domain Name TLV.
 
     /**
      * Returns the Type value.
@@ -1039,6 +1041,11 @@ class UdpEncapsulationTlvHeader
     // Followed by the UDP Payload.
 } OT_TOOL_PACKED_END;
 
+/**
+ * Implements Thread Domain Name TLV type.
+ */
+typedef StringTlvInfo<Tlv::kThreadDomainName, Tlv::kMaxThreadDomainNameLength> ThreadDomainNameTlv;
+
 /**
  * Implements Discovery Request TLV generation and parsing.
  *

src/core/meshcop/network_name.cpp

@@ -35,6 +35,7 @@
 #include "network_name.hpp"
 
 #include "instance/instance.hpp"
+#include "common/string.hpp"
 
 namespace ot {
 namespace MeshCoP {
@@ -158,6 +159,11 @@ Error NetworkNameManager::SetDomainName(const NameData &aNameData)
 
     return (error == kErrorAlready) ? kErrorNone : error;
 }
+
+bool NetworkNameManager::IsDefaultDomainNameSet()
+{
+    return StringMatch(mDomainName.GetAsCString(), NetworkName::kDomainNameInit);
+}
 #endif // (OPENTHREAD_CONFIG_THREAD_VERSION >= OT_THREAD_VERSION_1_2)
 
 } // namespace MeshCoP

src/core/meshcop/network_name.hpp

@@ -108,7 +108,7 @@ class NetworkName : public otNetworkName, public Unequatable<NetworkName>
 {
 public:
     static constexpr const char *kNetworkNameInit = "OpenThread";
-    static constexpr const char *kDomainNameInit  = "DefaultDomain";
+    static constexpr const char *kDomainNameInit  = "DefaultDomain"; // Section 5.22 Thread spec, MUST NOT change.
 
     /**
      * This constant specified the maximum number of chars in Network Name (excludes null char).
@@ -260,6 +260,14 @@ class NetworkNameManager : public InstanceLocator, private NonCopyable
      *
      */
     Error SetDomainName(const NameData &aNameData);
+
+    /**
+     * Checks whether the Thread Domain Name is currently set to the default name.
+     *
+     * @returns true if Thread Domain Name equals "DefaultDomain", false otherwise.
+     */
+    bool IsDefaultDomainNameSet();
+
 #endif // (OPENTHREAD_CONFIG_THREAD_VERSION >= OT_THREAD_VERSION_1_2)
 
 private:

src/core/thread/mle_router.cpp

@@ -2758,6 +2758,13 @@ Error MleRouter::SendDiscoveryResponse(const Ip6::Address &aDestination, const M
     SuccessOrExit(
         error = Tlv::Append<MeshCoP::JoinerUdpPortTlv>(*message, Get<MeshCoP::JoinerRouter>().GetJoinerUdpPort()));
 
+#if (OPENTHREAD_CONFIG_THREAD_VERSION >= OT_THREAD_VERSION_1_4)
+    if (!Get<MeshCoP::NetworkNameManager>().IsDefaultDomainNameSet())
+    {
+        SuccessOrExit(error = Tlv::Append<MeshCoP::ThreadDomainNameTlv>(*message, Get<MeshCoP::NetworkNameManager>().GetDomainName().GetAsCString()));
+    }
+#endif
+
     tlv.SetLength(static_cast<uint8_t>(message->GetLength() - startOffset));
     message->Write(startOffset - sizeof(tlv), tlv);