[ip6] log checksum error from Checksum::VerifyMessageChecksum() (#9556)

src/core/net/checksum.cpp

@@ -34,14 +34,18 @@
 #include "checksum.hpp"
 
 #include "common/code_utils.hpp"
+#include "common/log.hpp"
 #include "common/message.hpp"
 #include "net/icmp6.hpp"
 #include "net/ip4_types.hpp"
+#include "net/ip6.hpp"
 #include "net/tcp6.hpp"
 #include "net/udp6.hpp"
 
 namespace ot {
 
+RegisterLogModule("Ip6");
+
 void Checksum::AddUint8(uint8_t aUint8)
 {
     uint16_t newValue = mValue;
@@ -147,11 +151,18 @@ void Checksum::Calculate(const Ip4::Address &aSource,
 
 Error Checksum::VerifyMessageChecksum(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo, uint8_t aIpProto)
 {
+    Error    error = kErrorNone;
     Checksum checksum;
 
     checksum.Calculate(aMessageInfo.GetPeerAddr(), aMessageInfo.GetSockAddr(), aIpProto, aMessage);
 
-    return (checksum.GetValue() == kValidRxChecksum) ? kErrorNone : kErrorDrop;
+    if (checksum.GetValue() != kValidRxChecksum)
+    {
+        LogNote("Bad %s checksum", Ip6::Ip6::IpProtoToString(aIpProto));
+        error = kErrorDrop;
+    }
+
+    return error;
 }
 
 void Checksum::UpdateMessageChecksum(Message            &aMessage,

src/core/net/ip6.cpp

@@ -905,18 +905,10 @@ Error Ip6::HandlePayload(Header            &aIp6Header,
 #if OPENTHREAD_CONFIG_TCP_ENABLE
     case kProtoTcp:
         error = mTcp.HandleMessage(aIp6Header, *messagePtr, aMessageInfo);
-        if (error == kErrorDrop)
-        {
-            LogNote("Error TCP Checksum");
-        }
         break;
 #endif
     case kProtoUdp:
         error = mUdp.HandleMessage(*messagePtr, aMessageInfo);
-        if (error == kErrorDrop)
-        {
-            LogNote("Error UDP Checksum");
-        }
         break;
 
     case kProtoIcmp6: