SabrehavenServer/src/protocol.cpp
2020-07-26 13:23:05 +03:00

111 lines
2.7 KiB
C++

/**
* Tibia GIMUD Server - a free and open-source MMORPG server emulator
* Copyright (C) 2019 Sabrehaven and Mark Samman <mark.samman@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "otpch.h"
#include "protocol.h"
#include "outputmessage.h"
#include "rsa.h"
#include "xtea.h"
extern RSA g_RSA;
void Protocol::onSendMessage(const OutputMessage_ptr& msg) const
{
if (!rawMessages) {
msg->writeMessageLength();
if (encryptionEnabled) {
XTEA_encrypt(*msg);
msg->addCryptoHeader(checksumEnabled);
}
}
}
void Protocol::onRecvMessage(NetworkMessage& msg)
{
if (encryptionEnabled && !XTEA_decrypt(msg)) {
return;
}
parsePacket(msg);
}
OutputMessage_ptr Protocol::getOutputBuffer(int32_t size)
{
//dispatcher thread
if (!outputBuffer) {
outputBuffer = OutputMessagePool::getOutputMessage();
}
else if ((outputBuffer->getLength() + size) > NetworkMessage::MAX_PROTOCOL_BODY_LENGTH) {
send(outputBuffer);
outputBuffer = OutputMessagePool::getOutputMessage();
}
return outputBuffer;
}
void Protocol::XTEA_encrypt(OutputMessage& msg) const
{
// The message must be a multiple of 8
size_t paddingBytes = msg.getLength() % 8u;
if (paddingBytes != 0) {
msg.addPaddingBytes(8 - paddingBytes);
}
uint8_t* buffer = msg.getOutputBuffer();
xtea::encrypt(buffer, msg.getLength(), key);
}
bool Protocol::XTEA_decrypt(NetworkMessage& msg) const
{
if (((msg.getLength() - 6) & 7) != 0) {
return false;
}
uint8_t* buffer = msg.getBuffer() + msg.getBufferPosition();
xtea::decrypt(buffer, msg.getLength() - 6, key);
uint16_t innerLength = msg.get<uint16_t>();
if (innerLength + 8 > msg.getLength()) {
return false;
}
msg.setLength(innerLength);
return true;
}
bool Protocol::RSA_decrypt(NetworkMessage& msg)
{
if ((msg.getLength() - msg.getBufferPosition()) < 128) {
return false;
}
g_RSA.decrypt(reinterpret_cast<char*>(msg.getBuffer()) + msg.getBufferPosition()); //does not break strict aliasing
return msg.getByte() == 0;
}
uint32_t Protocol::getIP() const
{
if (auto connection = getConnection()) {
return connection->getIP();
}
return 0;
}