eq2go/old/common/packet/eq_packet.hpp

// Copyright (C) 2007 EQ2EMulator Development Team - GPL v3+ License

#pragma once

#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <string>
#include <cstring>
#include <map>
#include <sys/time.h>
#include <netinet/in.h>
#include <memory>

#include "packet_dump.hpp"
#include "../log.hpp"
#include "../misc.hpp"
#include "../debug.hpp"
#include "../types.hpp"
#include "../crc16.hpp"
#include "../opcodes/opcodes.hpp"
#include "../opcodes/emu_opcodes.hpp"
#include "../opcodes/opcode_manager.hpp"

using namespace std;
extern map<int16,OpcodeManager*>EQOpcodeManager;

class OpcodeManager;
class EQStream;

// Base packet class for all EverQuest protocol packets
class EQPacket
{
	friend class EQStream;

public:
	unsigned char *pBuffer;				// Raw packet data buffer
	uint32 size;						// Size of packet data
	uint32 src_ip, dst_ip;				// Source and destination IP addresses
	uint16 src_port, dst_port;			// Source and destination ports
	uint32 priority;					// Packet priority for queuing
	timeval timestamp;					// Timestamp when packet was created/received
	int16 version;						// Protocol version

	// Destructor - cleans up allocated buffer
	~EQPacket()
	{
		safe_delete_array(pBuffer);
		pBuffer = nullptr;
	}

	// Dumps packet header with timestamp information to file
	void DumpRawHeader(uint16 seq = 0xffff, FILE* to = stdout) const
	{
		DumpRawHeaderNoTime(seq, to);
	}

	// Dumps packet header without timestamp information to file
	void DumpRawHeaderNoTime(uint16 seq = 0xffff, FILE* to = stdout) const
	{
		if (src_ip) {
			string sIP = long2ip(src_ip);
			string dIP = long2ip(dst_ip);
			fprintf(to, "[%s:%d->%s:%d] ", sIP.c_str(), src_port, dIP.c_str(), dst_port);
		}

		if (seq != 0xffff)
			fprintf(to, "[Seq=%u] ", seq);

		string name;
		int16 OpcodeVersion = GetOpcodeVersion(version);
		if (EQOpcodeManager.count(OpcodeVersion) > 0)
			name = EQOpcodeManager[OpcodeVersion]->EQToName(opcode);

		fprintf(to, "[OpCode 0x%04x (%s) Size=%u]\n", opcode, name.c_str(), size);
	}

	// Dumps complete packet with header and data in hex format
	void DumpRaw(FILE* to = stdout) const
	{
		DumpRawHeader();
		if (pBuffer && size)
			dump_message_column(pBuffer, size, " ", to);
		fprintf(to, "\n");
	}

	// Gets human-readable name for packet opcode
	const char* GetOpcodeName()
	{
		int16 OpcodeVersion = GetOpcodeVersion(version);
		if (EQOpcodeManager.count(OpcodeVersion) > 0)
			return EQOpcodeManager[OpcodeVersion]->EQToName(opcode);
		else
			return nullptr;
	}

	// Sets protocol version for this packet
	void setVersion(int16 new_version) { version = new_version; }

	// Sets source IP and port information
	void setSrcInfo(uint32 sip, uint16 sport) { src_ip = sip; src_port = sport; }

	// Sets destination IP and port information
	void setDstInfo(uint32 dip, uint16 dport) { dst_ip = dip; dst_port = dport; }

	// Sets timestamp information for packet timing
	void setTimeInfo(uint32 ts_sec, uint32 ts_usec) { timestamp.tv_sec = ts_sec; timestamp.tv_usec = ts_usec; }

	// Copies connection and timing info from another packet
	void copyInfo(const EQPacket* p)
	{
		src_ip = p->src_ip;
		src_port = p->src_port;
		dst_ip = p->dst_ip;
		dst_port = p->dst_port;
		timestamp.tv_sec = p->timestamp.tv_sec;
		timestamp.tv_usec = p->timestamp.tv_usec;
	}

	// Returns total packet size including opcode header
	uint32 Size() const { return size + 2; }

	// Gets raw opcode value without translation
	uint16 GetRawOpcode() const { return opcode; }

	// Comparison operator for timestamp-based sorting
	inline bool operator<(const EQPacket& rhs)
	{
		return (timestamp.tv_sec < rhs.timestamp.tv_sec ||
			(timestamp.tv_sec == rhs.timestamp.tv_sec && timestamp.tv_usec < rhs.timestamp.tv_usec));
	}

	// Sets the protocol-level opcode
	void SetProtocolOpcode(int16 new_opcode) { opcode = new_opcode; }

protected:
	uint16 opcode;							// Packet opcode identifier

	// Constructor for creating packet with opcode and data buffer
	EQPacket(const uint16 op, const unsigned char* buf, uint32 len)
	{
		opcode = op;
		pBuffer = nullptr;
		size = 0;
		version = 0;
		setTimeInfo(0, 0);

		if (len > 0) {
			size = len;
			pBuffer = new unsigned char[size];
			if (buf) {
				memcpy(pBuffer, buf, size);
			} else {
				memset(pBuffer, 0, size);
			}
		}
	}

	// Copy constructor - disabled to prevent accidental copies
	EQPacket(const EQPacket& p) { version = 0; }

	// Default constructor
	EQPacket()
	{
		opcode = 0;
		pBuffer = nullptr;
		size = 0;
		version = 0;
		setTimeInfo(0, 0);
	}
};

class EQApplicationPacket;

// Protocol-level packet handling EverQuest network protocol specifics
class EQProtocolPacket : public EQPacket
{
public:
	bool eq2_compressed;					// Flag indicating if packet is compressed
	bool packet_prepared;					// Flag indicating if packet has been prepared for sending
	bool packet_encrypted;					// Flag indicating if packet is encrypted
	bool acked;								// Flag indicating if packet has been acknowledged
	int32 sent_time;						// Timestamp when packet was sent
	int8 attempt_count;						// Number of send attempts for this packet
	int32 sequence;							// Sequence number for ordering

	// Constructor with opcode and data buffer
	EQProtocolPacket(uint16 op, const unsigned char* buf, uint32 len) : EQPacket(op, buf, len)
	{
		eq2_compressed = false;
		packet_prepared = false;
		packet_encrypted = false;
		sequence = 0;
		sent_time = 0;
		attempt_count = 0;
		acked = false;
	}

	// Constructor from raw buffer with optional opcode override
	EQProtocolPacket(const unsigned char* buf, uint32 len, int in_opcode = -1)
	{
		uint32 offset = 0;
		if (in_opcode >= 0) {
			opcode = in_opcode;
		} else {
			// Ensure there are at least 2 bytes for the opcode
			if (len < 2 || buf == nullptr) {
				opcode = 0;
				offset = len;
			} else {
				offset = 2;
				opcode = ntohs(*(const uint16*)buf);
			}
		}

		// Check that there is payload data after the header
		if (len > offset) {
			size = len - offset;
			pBuffer = new unsigned char[size];
			if (buf)
				memcpy(pBuffer, buf + offset, size);
			else
				memset(pBuffer, 0, size);
		} else {
			pBuffer = nullptr;
			size = 0;
		}

		version = 0;
		eq2_compressed = false;
		packet_prepared = false;
		packet_encrypted = false;
		sent_time = 0;
		attempt_count = 0;
		sequence = 0;
	}

	// Attempts to combine this packet with another protocol packet for efficiency
	bool combine(const EQProtocolPacket* rhs)
	{
		bool result = false;

		// Check if this is already a combined packet and we can add more
		if (opcode == OP_Combined && size + rhs->size + 5 < 256) {
			auto tmpbuffer = new unsigned char[size + rhs->size + 3];
			memcpy(tmpbuffer, pBuffer, size);
			uint32 offset = size;
			tmpbuffer[offset++] = rhs->Size();
			offset += rhs->serialize(tmpbuffer + offset);
			size = offset;
			delete[] pBuffer;
			pBuffer = tmpbuffer;
			result = true;
		}
		// Check if we can create a new combined packet from two individual packets
		else if (size + rhs->size + 7 < 256) {
			auto tmpbuffer = new unsigned char[size + rhs->size + 6];
			uint32 offset = 0;
			tmpbuffer[offset++] = Size();
			offset += serialize(tmpbuffer + offset);
			tmpbuffer[offset++] = rhs->Size();
			offset += rhs->serialize(tmpbuffer + offset);
			size = offset;
			delete[] pBuffer;
			pBuffer = tmpbuffer;
			opcode = OP_Combined;
			result = true;
		}
		return result;
	}

	// Serializes packet data to destination buffer with optional offset
	uint32 serialize(unsigned char* dest, int8 offset = 0) const
	{
		if (opcode > 0xff) {
			*(uint16*)dest = opcode;
		} else {
			*(dest) = 0;
			*(dest + 1) = opcode;
		}
		memcpy(dest + 2, pBuffer + offset, size - offset);

		return size + 2;
	}

	// Creates a deep copy of this protocol packet
	EQProtocolPacket* Copy()
	{
		EQProtocolPacket* new_packet = new EQProtocolPacket(opcode, pBuffer, size);
		new_packet->eq2_compressed = this->eq2_compressed;
		new_packet->packet_prepared = this->packet_prepared;
		new_packet->packet_encrypted = this->packet_encrypted;
		return new_packet;
	}

	// Converts protocol packet to application packet for higher-level processing
	EQApplicationPacket* MakeApplicationPacket(uint8 opcode_size = 0) const;

	// Validates CRC checksum on received packet data
	static bool ValidateCRC(const unsigned char* buffer, int length, uint32 Key)
	{
		bool valid = false;

		// OP_SessionRequest, OP_SessionResponse, OP_OutOfSession are not CRC'd
		if (buffer[0] == 0x00 && (buffer[1] == OP_SessionRequest || buffer[1] == OP_SessionResponse || buffer[1] == OP_OutOfSession)) {
			valid = true;
		} else if (buffer[2] == 0x00 && buffer[3] == 0x19) {
			valid = true;
		} else {
			uint16 comp_crc = CRC16(buffer, length - 2, Key);
			uint16 packet_crc = ntohs(*(const uint16*)(buffer + length - 2));
			valid = (!packet_crc || comp_crc == packet_crc);
		}
		return valid;
	}

	// Decompresses packet data using zlib inflation
	static uint32 Decompress(const unsigned char* buffer, const uint32 length, unsigned char* newbuf, uint32 newbufsize)
	{
		uint32 newlen = 0;
		uint32 flag_offset = 0;
		newbuf[0] = buffer[0];

		if (buffer[0] == 0x00) {
			flag_offset = 2;
			newbuf[1] = buffer[1];
		} else {
			flag_offset = 1;
		}

		if (length > 2 && buffer[flag_offset] == 0x5a) {
			LogWrite(PACKET__DEBUG, 0, "Packet", "In Decompress 1");
			newlen = Inflate(const_cast<unsigned char*>(buffer + flag_offset + 1), length - (flag_offset + 1) - 2, newbuf + flag_offset, newbufsize - flag_offset) + 2;

			// something went bad with zlib
			if (newlen == -1) {
				LogWrite(PACKET__ERROR, 0, "Packet", "Debug Bad Inflate!");
				DumpPacket(buffer, length);
				memcpy(newbuf, buffer, length);
				return length;
			}

			newbuf[newlen++] = buffer[length - 2];
			newbuf[newlen++] = buffer[length - 1];
		} else if (length > 2 && buffer[flag_offset] == 0xa5) {
			LogWrite(PACKET__DEBUG, 0, "Packet", "In Decompress 2");
			memcpy(newbuf + flag_offset, buffer + flag_offset + 1, length - (flag_offset + 1));
			newlen = length - 1;
		} else {
			memcpy(newbuf, buffer, length);
			newlen = length;
		}

		return newlen;
	}

	// Compresses packet data using zlib deflation
	static uint32 Compress(const unsigned char* buffer, const uint32 length, unsigned char* newbuf, uint32 newbufsize)
	{
		uint32 flag_offset = 1, newlength;
		newbuf[0] = buffer[0];

		if (buffer[0] == 0) {
			flag_offset = 2;
			newbuf[1] = buffer[1];
		}

		if (length > 30) {
			newlength = Deflate(const_cast<unsigned char*>(buffer + flag_offset), length - flag_offset, newbuf + flag_offset + 1, newbufsize);
			*(newbuf + flag_offset) = 0x5a;
			newlength += flag_offset + 1;
		} else {
			memmove(newbuf + flag_offset + 1, buffer + flag_offset, length - flag_offset);
			*(newbuf + flag_offset) = 0xa5;
			newlength = length + 1;
		}

		return newlength;
	}

	// Decodes chat message encryption
	static void ChatDecode(unsigned char* buffer, int size, int DecodeKey)
	{
		if (buffer[1] != 0x01 && buffer[0] != 0x02 && buffer[0] != 0x1d) {
			int Key = DecodeKey;
			unsigned char* test = (unsigned char*)malloc(size);
			buffer += 2;
			size -= 2;

			int i;
			for (i = 0; i + 4 <= size; i += 4) {
				int pt = (*(int*)&buffer[i]) ^ (Key);
				Key = (*(int*)&buffer[i]);
				*(int*)&test[i] = pt;
			}
			unsigned char KC = Key & 0xFF;
			for (; i < size; i++) {
				test[i] = buffer[i] ^ KC;
			}
			memcpy(buffer, test, size);
			free(test);
		}
	}

	// Encodes chat message with encryption
	static void ChatEncode(unsigned char* buffer, int size, int EncodeKey)
	{
		if (buffer[1] != 0x01 && buffer[0] != 0x02 && buffer[0] != 0x1d) {
			int Key = EncodeKey;
			char* test = (char*)malloc(size);
			int i;
			buffer += 2;
			size -= 2;
			for (i = 0; i + 4 <= size; i += 4) {
				int pt = (*(int*)&buffer[i]) ^ (Key);
				Key = pt;
				*(int*)&test[i] = pt;
			}
			unsigned char KC = Key & 0xFF;
			for (; i < size; i++) {
				test[i] = buffer[i] ^ KC;
			}
			memcpy(buffer, test, size);
			free(test);
		}
	}

	// Determines if buffer contains a valid protocol packet
	static bool IsProtocolPacket(const unsigned char* in_buff, uint32_t len, bool bTrimCRC)
	{
		bool ret = false;
		uint16_t opcode = ntohs(*(uint16_t*)in_buff);

		switch (opcode) {
		case OP_SessionRequest:
		case OP_SessionDisconnect:
		case OP_KeepAlive:
		case OP_SessionStatResponse:
		case OP_Packet:
		case OP_Combined:
		case OP_Fragment:
		case OP_Ack:
		case OP_OutOfOrderAck:
		case OP_OutOfSession:
			ret = true;
			break;
		}

		return ret;
	}

private:
	// Copy constructor disabled to prevent accidental copies
	EQProtocolPacket(const EQProtocolPacket& p) {}
};

// EverQuest 2 specific packet handling with login opcodes
class EQ2Packet : public EQProtocolPacket
{
public:
	EmuOpcode login_op;						// EmuOpcode for this packet

	// Constructor with login opcode and data buffer
	EQ2Packet(const EmuOpcode in_login_op, const unsigned char* buf, uint32 len) : EQProtocolPacket(OP_Packet, buf, len)
	{
		login_op = in_login_op;
		eq2_compressed = false;
		packet_prepared = false;
		packet_encrypted = false;
	}

	// Attempts to combine this EQ2 packet with another for transmission efficiency
	bool AppCombine(EQ2Packet* rhs)
	{
		bool result = false;
		uchar* tmpbuffer = nullptr;
		bool over_sized_packet = false;
		int32 new_size = 0;

		// If this is already a combined packet and we can add more
		if (opcode == OP_AppCombined && ((size + rhs->size + 3) < 255)) {
			int16 tmp_size = rhs->size - 2;
			if (tmp_size >= 255) {
				new_size = size + tmp_size + 3;
				over_sized_packet = true;
			} else {
				new_size = size + tmp_size + 1;
			}

			tmpbuffer = new uchar[new_size];
			uchar* ptr = tmpbuffer;
			memcpy(ptr, pBuffer, size);
			ptr += size;

			if (over_sized_packet) {
				memset(ptr, 255, sizeof(int8));
				ptr += sizeof(int8);
				tmp_size = htons(tmp_size);
				memcpy(ptr, &tmp_size, sizeof(int16));
				ptr += sizeof(int16);
			} else {
				memcpy(ptr, &tmp_size, sizeof(int8));
				ptr += sizeof(int8);
			}

			memcpy(ptr, rhs->pBuffer + 2, rhs->size - 2);
			delete[] pBuffer;
			size = new_size;
			pBuffer = tmpbuffer;
			safe_delete(rhs);
			result = true;
		}
		// Create a new combined packet from two individual packets
		else if (rhs->size > 2 && size > 2 && (size + rhs->size + 6) < 255) {
			int32 tmp_size = size - 2;
			int32 tmp_size2 = rhs->size - 2;
			opcode = OP_AppCombined;
			bool over_sized_packet2 = false;
			new_size = size;

			if (tmp_size >= 255) {
				new_size += 5;
				over_sized_packet = true;
			} else {
				new_size += 3;
			}

			if (tmp_size2 >= 255) {
				new_size += tmp_size2 + 3;
				over_sized_packet2 = true;
			} else {
				new_size += tmp_size2 + 1;
			}

			tmpbuffer = new uchar[new_size];
			tmpbuffer[2] = 0;
			tmpbuffer[3] = 0x19;
			uchar* ptr = tmpbuffer + 4;

			if (over_sized_packet) {
				memset(ptr, 255, sizeof(int8));
				ptr += sizeof(int8);
				tmp_size = htons(tmp_size);
				memcpy(ptr, &tmp_size, sizeof(int16));
				ptr += sizeof(int16);
			} else {
				memcpy(ptr, &tmp_size, sizeof(int8));
				ptr += sizeof(int8);
			}

			memcpy(ptr, pBuffer + 2, size - 2);
			ptr += (size - 2);

			if (over_sized_packet2) {
				memset(ptr, 255, sizeof(int8));
				ptr += sizeof(int8);
				tmp_size2 = htons(tmp_size2);
				memcpy(ptr, &tmp_size2, sizeof(int16));
				ptr += sizeof(int16);
			} else {
				memcpy(ptr, &tmp_size2, sizeof(int8));
				ptr += sizeof(int8);
			}

			memcpy(ptr, rhs->pBuffer + 2, rhs->size - 2);
			size = new_size;
			delete[] pBuffer;
			pBuffer = tmpbuffer;
			safe_delete(rhs);
			result = true;
		}

		return result;
	}

	// Creates a deep copy of this EQ2 packet
	EQ2Packet* Copy()
	{
		EQ2Packet* new_packet = new EQ2Packet(login_op, pBuffer, size);
		new_packet->eq2_compressed = this->eq2_compressed;
		new_packet->packet_prepared = this->packet_prepared;
		new_packet->packet_encrypted = this->packet_encrypted;
		return new_packet;
	}

	// Prepares packet for transmission by adding headers and opcodes
	int8 PreparePacket(int16 MaxLen)
	{
		int16 OpcodeVersion = GetOpcodeVersion(version);

		// stops a crash for incorrect version
		if (EQOpcodeManager.count(OpcodeVersion) == 0) {
			LogWrite(PACKET__ERROR, 0, "Packet", "Version %i is not listed in the opcodes table.", version);
			return -1;
		}

		packet_prepared = true;

		int16 login_opcode = EQOpcodeManager[OpcodeVersion]->EmuToEQ(login_op);
		if (login_opcode == 0xcdcd) {
			LogWrite(PACKET__ERROR, 0, "Packet", "Version %i is not listed in the opcodes table for opcode %s", version, EQOpcodeManager[OpcodeVersion]->EmuToName(login_op));
			return -1;
		}

		int16 orig_opcode = login_opcode;
		int8 offset = 0;
		// one of the int16s is for the seq, other is for the EQ2 opcode and compressed flag (OP_Packet is the header, not the opcode)
		int32 new_size = size + sizeof(int16) + sizeof(int8);
		bool oversized = false;

		if (login_opcode != 2) {
			new_size += sizeof(int8); // for opcode
			if (login_opcode >= 255) {
				new_size += sizeof(int16);
				oversized = true;
			} else {
				login_opcode = ntohs(login_opcode);
			}
		}

		uchar* new_buffer = new uchar[new_size];
		memset(new_buffer, 0, new_size);
		uchar* ptr = new_buffer + sizeof(int16); // sequence is first

		if (login_opcode != 2) {
			if (oversized) {
				ptr += sizeof(int8); // compressed flag
				int8 addon = 0xff;
				memcpy(ptr, &addon, sizeof(int8));
				ptr += sizeof(int8);
			}
			memcpy(ptr, &login_opcode, sizeof(int16));
			ptr += sizeof(int16);
		} else {
			memcpy(ptr, &login_opcode, sizeof(int8));
			ptr += sizeof(int8);
		}

		memcpy(ptr, pBuffer, size);

		safe_delete_array(pBuffer);
		pBuffer = new_buffer;
		offset = new_size - size - 1;
		size = new_size;

		return offset;
	}

	// Gets human-readable name for the login opcode
	const char* GetOpcodeName()
	{
		int16 OpcodeVersion = GetOpcodeVersion(version);
		if (EQOpcodeManager.count(OpcodeVersion) > 0)
			return EQOpcodeManager[OpcodeVersion]->EmuToName(login_op);
		else
			return nullptr;
	}
};

// Application-level packet handling for game logic
class EQApplicationPacket : public EQPacket
{
	friend class EQProtocolPacket;
	friend class EQStream;

public:
	static uint8 default_opcode_size;		// Default size for opcodes in bytes

	// Default constructor
	EQApplicationPacket() : EQPacket(0, nullptr, 0)
	{
		emu_opcode = OP_Unknown;
		app_opcode_size = default_opcode_size;
	}

	// Constructor with opcode only
	EQApplicationPacket(const EmuOpcode op) : EQPacket(0, nullptr, 0)
	{
		SetOpcode(op);
		app_opcode_size = default_opcode_size;
	}

	// Constructor with opcode and length
	EQApplicationPacket(const EmuOpcode op, const uint32 len) : EQPacket(0, nullptr, len)
	{
		SetOpcode(op);
		app_opcode_size = default_opcode_size;
	}

	// Constructor with opcode, buffer and length
	EQApplicationPacket(const EmuOpcode op, const unsigned char* buf, const uint32 len) : EQPacket(0, buf, len)
	{
		SetOpcode(op);
		app_opcode_size = default_opcode_size;
	}

	// Attempts to combine this application packet with another (currently not implemented)
	bool combine(const EQApplicationPacket* rhs)
	{
		cout << "CALLED AP COMBINE!!!!\n";
		return false;
	}

	// Serializes application packet to destination buffer
	uint32 serialize(unsigned char* dest) const
	{
		uint8 OpCodeBytes = app_opcode_size;

		if (app_opcode_size == 1) {
			*(unsigned char*)dest = opcode;
		} else {
			// Application opcodes with a low order byte of 0x00 require an extra 0x00 byte inserting prior to the opcode.
			if ((opcode & 0x00ff) == 0) {
				*(uint8*)dest = 0;
				*(uint16*)(dest + 1) = opcode;
				++OpCodeBytes;
			} else {
				*(uint16*)dest = opcode;
			}
		}

		memcpy(dest + app_opcode_size, pBuffer, size);

		return size + OpCodeBytes;
	}

	// Returns total packet size including opcode
	uint32 Size() const { return size + app_opcode_size; }

	// Creates a deep copy of this application packet
	EQApplicationPacket* Copy() const
	{
		EQApplicationPacket* it = new EQApplicationPacket;
		try {
			it->pBuffer = new unsigned char[size];
			memcpy(it->pBuffer, pBuffer, size);
			it->size = size;
			it->opcode = opcode;
			it->emu_opcode = emu_opcode;
			it->version = version;
			return it;
		}
		catch (bad_alloc& ba) {
			cout << ba.what() << endl;
			if (it != nullptr)
				delete it;
		}
		return nullptr;
	}

	// Sets the opcode size for this packet
	void SetOpcodeSize(uint8 s) { app_opcode_size = s; }

	// Sets the opcode for this packet using EmuOpcode
	void SetOpcode(EmuOpcode emu_op)
	{
		if (emu_op == OP_Unknown) {
			opcode = 0;
			emu_opcode = OP_Unknown;
			return;
		}

		opcode = EQOpcodeManager[GetOpcodeVersion(version)]->EmuToEQ(emu_op);

		if (opcode == OP_Unknown) {
			LogWrite(PACKET__DEBUG, 0, "Packet", "Unable to convert Emu opcode %s (%d) into an EQ opcode.", OpcodeNames[emu_op], emu_op);
		}

		// save the emu opcode we just set.
		emu_opcode = emu_op;
	}

	// Gets the constant opcode value for this packet
	const EmuOpcode GetOpcodeConst() const
	{
		if (emu_opcode != OP_Unknown) {
			return emu_opcode;
		}
		if (opcode == 10000) {
			return OP_Unknown;
		}

		EmuOpcode emu_op;
		emu_op = EQOpcodeManager[GetOpcodeVersion(version)]->EQToEmu(opcode);
		if (emu_op == OP_Unknown) {
			LogWrite(PACKET__DEBUG, 1, "Packet", "Unable to convert EQ opcode 0x%.4X (%i) to an emu opcode (%s)", opcode, opcode, __FUNCTION__);
		}

		return emu_op;
	}

	// Gets the opcode for this packet (const version)
	inline const EmuOpcode GetOpcode() const { return GetOpcodeConst(); }

	// Gets the opcode for this packet (caching version)
	inline const EmuOpcode GetOpcode() { EmuOpcode r = GetOpcodeConst(); emu_opcode = r; return r; }

protected:
	EmuOpcode emu_opcode;					// Cached emu opcode to avoid repeated lookups

private:
	uint8 app_opcode_size;					// Size of opcode in bytes

	// Constructor from raw buffer - used internally by EQProtocolPacket
	EQApplicationPacket(const unsigned char* buf, uint32 len, uint8 opcode_size = 0)
	{
		uint32 offset = 0;
		app_opcode_size = (opcode_size == 0) ? EQApplicationPacket::default_opcode_size : opcode_size;

		if (app_opcode_size == 1) {
			opcode = *(const unsigned char*)buf;
			offset++;
		} else {
			opcode = *(const uint16*)buf;
			offset += 2;
		}

		if ((len - offset) > 0) {
			pBuffer = new unsigned char[len - offset];
			memcpy(pBuffer, buf + offset, len - offset);
			size = len - offset;
		} else {
			pBuffer = nullptr;
			size = 0;
		}

		emu_opcode = OP_Unknown;
	}

	// Copy constructor disabled to prevent accidental copies
	EQApplicationPacket(const EQApplicationPacket& p) { emu_opcode = OP_Unknown; app_opcode_size = default_opcode_size; }
};

// Implementation of MakeApplicationPacket that was forward declared
inline EQApplicationPacket* EQProtocolPacket::MakeApplicationPacket(uint8 opcode_size) const
{
	EQApplicationPacket* res = new EQApplicationPacket;
	res->app_opcode_size = (opcode_size == 0) ? EQApplicationPacket::default_opcode_size : opcode_size;

	if (res->app_opcode_size == 1) {
		res->pBuffer = new unsigned char[size + 1];
		memcpy(res->pBuffer + 1, pBuffer, size);
		*(res->pBuffer) = htons(opcode) & 0xff;
		res->opcode = opcode & 0xff;
		res->size = size + 1;
	} else {
		res->pBuffer = new unsigned char[size];
		memcpy(res->pBuffer, pBuffer, size);
		res->opcode = opcode;
		res->size = size;
	}
	res->copyInfo(this);
	return res;
}

// Global packet dumping functions for debugging

// Dumps application packet data in hexadecimal format
void DumpPacketHex(const EQApplicationPacket* app)
{
	DumpPacketHex(app->pBuffer, app->size);
}

// Dumps application packet data in ASCII format
void DumpPacketAscii(const EQApplicationPacket* app)
{
	DumpPacketAscii(app->pBuffer, app->size);
}

// Dumps protocol packet data in hexadecimal format
void DumpPacket(const EQProtocolPacket* app)
{
	DumpPacketHex(app->pBuffer, app->size);
}

// Dumps application packet with optional info display
void DumpPacket(const EQApplicationPacket* app, bool iShowInfo = false)
{
	if (iShowInfo) {
		cout << "Dumping Applayer: 0x" << hex << setfill('0') << setw(4) << app->GetOpcode() << dec;
		cout << " size:" << app->size << endl;
	}
	DumpPacketHex(app->pBuffer, app->size);
}

// Dumps application packet data in binary format
void DumpPacketBin(const EQApplicationPacket* app)
{
	DumpPacketBin(app->pBuffer, app->size);
}