feat(Core/Packet): Implement AntiDOS protection from Trinity (#2789)

* Implement AntiDOS protection from Trinity


Co-authored-by: jackpoz <giacomopoz@gmail.com>
Co-authored-by: Shauren <shauren.trinity@gmail.com>
Co-authored-by: Vincent-Michael <trinity.michael_vincent@gmx.eu>

src/server/game/Server/Protocol/Opcodes.h

@@ -13,12 +13,6 @@
 
 #include "Common.h"
 
-// Note: this include need for be sure have full definition of class WorldSession
-//       if this class definition not complete then VS for x64 release use different size for
-//       struct OpcodeHandler in this header and Opcode.cpp and get totally wrong data from
-//       table opcodeTable in source when Opcode.h included but WorldSession.h not included
-#include "WorldSession.h"
-
 /// List of Opcodes
 enum Opcodes
 {
@@ -1353,8 +1347,15 @@ enum PacketProcessing
     PROCESS_THREADSAFE                                      //packet is thread-safe - process it in Map::Update()
 };
 
+class WorldSession;
 class WorldPacket;
 
+#if defined(__GNUC__)
+#pragma pack(1)
+#else
+#pragma pack(push, 1)
+#endif
+
 struct OpcodeHandler
 {
     char const* name;
@@ -1365,6 +1366,12 @@ struct OpcodeHandler
 
 extern OpcodeHandler opcodeTable[NUM_MSG_TYPES];
 
+#if defined(__GNUC__)
+#pragma pack()
+#else
+#pragma pack(pop)
+#endif
+
 /// Lookup opcode name for human understandable logging
 inline const char* LookupOpcodeName(uint16 id)
 {