[joiner-router] enhance & fix appending TLVs to Joiner Entrust msg (#…

…9614)

This commit updates `JoinerRouter::PrepareJoinerEntrustMessage()` to
improve how TLVs from Active Operational Dataset are appended to the
message. The TLV types that should be included in Joiner Entrust are
now defined in an array `kTlvTypes`, and the code iterating over this
array will find the TLV in Dataset and append it to the message.

Previously, if a required TLV type was not present in the Dataset, the
code would have appended the TLV with an uninitialized and possibly
random value, which could lead to unexpected behavior. The new code
will fail if the required TLVs are not present in the Dataset
instead, ensuring that only valid TLVs are included in the Joiner
Entrust message.

src/core/meshcop/joiner_router.cpp

@@ -290,72 +290,29 @@ Error JoinerRouter::SendJoinerEntrust(const Ip6::MessageInfo &aMessageInfo)
 
 Coap::Message *JoinerRouter::PrepareJoinerEntrustMessage(void)
 {
-    Error          error;
+    static const Tlv::Type kTlvTypes[] = {
+        Tlv::kNetworkKey,      Tlv::kMeshLocalPrefix, Tlv::kExtendedPanId, Tlv::kNetworkName,
+        Tlv::kActiveTimestamp, Tlv::kChannelMask,     Tlv::kPskc,          Tlv::kSecurityPolicy,
+    };
+
+    Error          error   = kErrorNone;
     Coap::Message *message = nullptr;
     Dataset        dataset;
-    NetworkNameTlv networkName;
-    const Tlv     *tlv;
-    NetworkKey     networkKey;
 
     message = Get<Tmf::Agent>().NewPriorityConfirmablePostMessage(kUriJoinerEntrust);
     VerifyOrExit(message != nullptr, error = kErrorNoBufs);
 
     message->SetSubType(Message::kSubTypeJoinerEntrust);
 
-    Get<KeyManager>().GetNetworkKey(networkKey);
-    SuccessOrExit(error = Tlv::Append<NetworkKeyTlv>(*message, networkKey));
-    SuccessOrExit(error = Tlv::Append<MeshLocalPrefixTlv>(*message, Get<Mle::MleRouter>().GetMeshLocalPrefix()));
-    SuccessOrExit(error = Tlv::Append<ExtendedPanIdTlv>(*message, Get<ExtendedPanIdManager>().GetExtPanId()));
-
-    networkName.Init();
-    networkName.SetNetworkName(Get<NetworkNameManager>().GetNetworkName().GetAsData());
-    SuccessOrExit(error = networkName.AppendTo(*message));
-
-    IgnoreError(Get<ActiveDatasetManager>().Read(dataset));
-
-    if ((tlv = dataset.GetTlv<ActiveTimestampTlv>()) != nullptr)
-    {
-        SuccessOrExit(error = tlv->AppendTo(*message));
-    }
-    else
-    {
-        ActiveTimestampTlv activeTimestamp;
-        activeTimestamp.Init();
-        SuccessOrExit(error = activeTimestamp.AppendTo(*message));
-    }
-
-    if ((tlv = dataset.GetTlv<ChannelMaskTlv>()) != nullptr)
-    {
-        SuccessOrExit(error = tlv->AppendTo(*message));
-    }
-    else
-    {
-        ChannelMaskBaseTlv channelMask;
-        channelMask.Init();
-        SuccessOrExit(error = channelMask.AppendTo(*message));
-    }
+    SuccessOrExit(error = Get<ActiveDatasetManager>().Read(dataset));
 
-    if ((tlv = dataset.GetTlv<PskcTlv>()) != nullptr)
+    for (Tlv::Type tlvType : kTlvTypes)
     {
-        SuccessOrExit(error = tlv->AppendTo(*message));
-    }
-    else
-    {
-        PskcTlv pskc;
-        pskc.Init();
-        SuccessOrExit(error = pskc.AppendTo(*message));
-    }
+        const Tlv *tlv = dataset.GetTlv(tlvType);
 
-    if ((tlv = dataset.GetTlv<SecurityPolicyTlv>()) != nullptr)
-    {
+        VerifyOrExit(tlv != nullptr, error = kErrorInvalidState);
         SuccessOrExit(error = tlv->AppendTo(*message));
     }
-    else
-    {
-        SecurityPolicyTlv securityPolicy;
-        securityPolicy.Init();
-        SuccessOrExit(error = securityPolicy.AppendTo(*message));
-    }
 
     SuccessOrExit(error = Tlv::Append<NetworkKeySequenceTlv>(*message, Get<KeyManager>().GetCurrentKeySequence()));