[mesh-forwarder] fix and enhance LogMessage() (#7556)

This commit updates `LogMessage()` in `MeshForwarder`:
- Fixes `MessageActionToString()` so when there is a passed-in error
  it correctly returns the related action string (and only when
  `aAction == kMessageTransmit` it returned "Failed to send").
- Changes the order of parameters in `LogMessage()` and uses default
  value for parameters to simplify its use.

src/core/net/ip6.cpp

@@ -1214,7 +1214,7 @@ start:
         {
             // Remove encapsulating header and start over.
             aMessage.RemoveHeader(aMessage.GetOffset());
-            Get<MeshForwarder>().LogMessage(MeshForwarder::kMessageReceive, aMessage, nullptr, kErrorNone);
+            Get<MeshForwarder>().LogMessage(MeshForwarder::kMessageReceive, aMessage);
             goto start;
         }
 

src/core/thread/indirect_sender.cpp

@@ -320,7 +320,7 @@ void IndirectSender::UpdateIndirectMessage(Child &aChild)
         mDataPollHandler.HandleNewFrame(aChild);
 
         aChild.GetMacAddress(childAddress);
-        Get<MeshForwarder>().LogMessage(MeshForwarder::kMessagePrepareIndirect, *message, &childAddress, kErrorNone);
+        Get<MeshForwarder>().LogMessage(MeshForwarder::kMessagePrepareIndirect, *message, kErrorNone, &childAddress);
     }
 }
 
@@ -519,7 +519,7 @@ void IndirectSender::HandleSentFrameToChild(const Mac::TxFrame &aFrame,
         if (!aFrame.IsEmpty())
         {
             IgnoreError(aFrame.GetDstAddr(macDest));
-            Get<MeshForwarder>().LogMessage(MeshForwarder::kMessageTransmit, *message, &macDest, txError);
+            Get<MeshForwarder>().LogMessage(MeshForwarder::kMessageTransmit, *message, txError, &macDest);
         }
 
         if (message->GetType() == Message::kTypeIp6)

src/core/thread/mesh_forwarder.cpp

@@ -224,7 +224,7 @@ void MeshForwarder::RemoveMessage(Message &aMessage)
         }
     }
 
-    LogMessage(kMessageEvict, aMessage, nullptr, kErrorNoBufs);
+    LogMessage(kMessageEvict, aMessage, kErrorNoBufs);
     queue->DequeueAndFree(aMessage);
 }
 
@@ -320,7 +320,7 @@ Message *MeshForwarder::PrepareNextDirectTransmission(void)
 #endif
 
         default:
-            LogMessage(kMessageDrop, *curMessage, nullptr, error);
+            LogMessage(kMessageDrop, *curMessage, error);
             mSendQueue.DequeueAndFree(*curMessage);
             continue;
         }
@@ -1071,7 +1071,7 @@ void MeshForwarder::UpdateSendMessage(Error aFrameTxError, Mac::Address &aMacDes
     Get<Utils::HistoryTracker>().RecordTxMessage(*mSendMessage, aMacDest);
 #endif
 
-    LogMessage(kMessageTransmit, *mSendMessage, &aMacDest, txError);
+    LogMessage(kMessageTransmit, *mSendMessage, txError, &aMacDest);
 
     if (mSendMessage->GetType() == Message::kTypeIp6)
     {
@@ -1348,7 +1348,7 @@ void MeshForwarder::ClearReassemblyList(void)
 {
     for (Message &message : mReassemblyList)
     {
-        LogMessage(kMessageReassemblyDrop, message, nullptr, kErrorNoFrameReceived);
+        LogMessage(kMessageReassemblyDrop, message, kErrorNoFrameReceived);
 
         if (message.GetType() == Message::kTypeIp6)
         {
@@ -1385,7 +1385,7 @@ bool MeshForwarder::UpdateReassemblyList(void)
         }
         else
         {
-            LogMessage(kMessageReassemblyDrop, message, nullptr, kErrorReassemblyTimeout);
+            LogMessage(kMessageReassemblyDrop, message, kErrorReassemblyTimeout);
 
             if (message.GetType() == Message::kTypeIp6)
             {
@@ -1475,7 +1475,7 @@ Error MeshForwarder::HandleDatagram(Message &aMessage, const ThreadLinkInfo &aLi
     Get<Utils::HistoryTracker>().RecordRxMessage(aMessage, aMacSource);
 #endif
 
-    LogMessage(kMessageReceive, aMessage, &aMacSource, kErrorNone);
+    LogMessage(kMessageReceive, aMessage, kErrorNone, &aMacSource);
 
     if (aMessage.GetType() == Message::kTypeIp6)
     {
@@ -1713,6 +1713,8 @@ const char *MeshForwarder::MessageActionToString(MessageAction aAction, Error aE
         "Evicting",                    // (5) kMessageEvict
     };
 
+    const char *string = kMessageActionStrings[aAction];
+
     static_assert(kMessageReceive == 0, "kMessageReceive value is incorrect");
     static_assert(kMessageTransmit == 1, "kMessageTransmit value is incorrect");
     static_assert(kMessagePrepareIndirect == 2, "kMessagePrepareIndirect value is incorrect");
@@ -1720,7 +1722,12 @@ const char *MeshForwarder::MessageActionToString(MessageAction aAction, Error aE
     static_assert(kMessageReassemblyDrop == 4, "kMessageReassemblyDrop value is incorrect");
     static_assert(kMessageEvict == 5, "kMessageEvict value is incorrect");
 
-    return (aError == kErrorNone) ? kMessageActionStrings[aAction] : "Failed to send";
+    if ((aAction == kMessageTransmit) && (aError != kErrorNone))
+    {
+        string = "Failed to send";
+    }
+
+    return string;
 }
 
 const char *MeshForwarder::MessagePriorityToString(const Message &aMessage)
@@ -1803,8 +1810,9 @@ exit:
 
 void MeshForwarder::LogMessage(MessageAction       aAction,
                                const Message &     aMessage,
-                               const Mac::Address *aMacAddress,
-                               Error               aError)
+                               Error               aError,
+                               const Mac::Address *aMacAddress)
+
 {
     LogLevel logLevel = kLogLevelInfo;
 
@@ -1882,7 +1890,7 @@ void MeshForwarder::LogLowpanHcFrameDrop(Error               aError,
 
 #else // #if OT_SHOULD_LOG_AT( OT_LOG_LEVEL_NOTE)
 
-void MeshForwarder::LogMessage(MessageAction, const Message &, const Mac::Address *, Error)
+void MeshForwarder::LogMessage(MessageAction, const Message &, Error, const Mac::Address *)
 {
 }
 

src/core/thread/mesh_forwarder.hpp

@@ -512,7 +512,11 @@ private:
     void PauseMessageTransmissions(void) { mTxPaused = true; }
     void ResumeMessageTransmissions(void);
 
-    void LogMessage(MessageAction aAction, const Message &aMessage, const Mac::Address *aAddress, Error aError);
+    void LogMessage(MessageAction       aAction,
+                    const Message &     aMessage,
+                    Error               aError   = kErrorNone,
+                    const Mac::Address *aAddress = nullptr);
+
     void LogFrame(const char *aActionText, const Mac::Frame &aFrame, Error aError);
     void LogFragmentFrameDrop(Error                         aError,
                               uint16_t                      aFrameLength,

src/core/thread/mesh_forwarder_ftd.cpp

@@ -169,7 +169,7 @@ void MeshForwarder::HandleResolved(const Ip6::Address &aEid, Error aError)
             }
             else
             {
-                LogMessage(kMessageDrop, message, nullptr, aError);
+                LogMessage(kMessageDrop, message, aError);
                 message.Free();
             }
         }
@@ -349,7 +349,7 @@ void MeshForwarder::RemoveDataResponseMessages(void)
             mSendMessage = nullptr;
         }
 
-        LogMessage(kMessageDrop, message, nullptr, kErrorNone);
+        LogMessage(kMessageDrop, message);
         mSendQueue.DequeueAndFree(message);
     }
 }
@@ -807,7 +807,7 @@ void MeshForwarder::HandleMesh(uint8_t *             aFrame,
         message->SetRadioType(static_cast<Mac::RadioType>(aLinkInfo.mRadioType));
 #endif
 
-        LogMessage(kMessageReceive, *message, &aMacSource, kErrorNone);
+        LogMessage(kMessageReceive, *message, kErrorNone, &aMacSource);
 
 #if OPENTHREAD_CONFIG_MULTI_RADIO
         // Since the message will be forwarded, we clear the radio