/* The MIT License * * Copyright (c) 2010 OTClient, https://github.com/edubart/otclient * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include Protocol::Protocol() : m_connection(new Connection) { m_connection->setErrorCallback(boost::bind(&Protocol::onError, this, _1)); m_connection->setRecvCallback(boost::bind(&Protocol::onRecv, this, _1)); m_xteaEncryptionEnabled = false; } void Protocol::connect(const std::string& host, uint16 port, const SimpleCallback& callback) { m_connection->connect(host, port, callback); } void Protocol::send(OutputMessage *outputMessage) { // Encrypt if(m_xteaEncryptionEnabled) xteaEncrypt(outputMessage); // Set checksum uint32 checksum = getAdlerChecksum(outputMessage->getBuffer() + OutputMessage::DATA_POS, outputMessage->getMessageSize()); outputMessage->setWritePos(OutputMessage::CHECKSUM_POS); outputMessage->addU32(checksum); // Set size uint16 messageSize = outputMessage->getMessageSize(); outputMessage->setWritePos(OutputMessage::HEADER_POS); outputMessage->addU16(messageSize); // Send m_connection->send(outputMessage); } void Protocol::onRecv(InputMessage *inputMessage) { uint32 checksum = getAdlerChecksum(inputMessage->getBuffer() + InputMessage::DATA_POS, inputMessage->getMessageSize() - InputMessage::CHECKSUM_LENGTH); if(inputMessage->getU32() != checksum) { // error logError("Checksum is invalid."); return; } if(m_xteaEncryptionEnabled) xteaDecrypt(inputMessage); } void Protocol::onError(const boost::system::error_code& error) { flogError("PROTOCOL ERROR: %s", error.message()); // invalid hostname // connection timeouted // displays a dialog, finish protocol } bool Protocol::xteaDecrypt(InputMessage *inputMessage) { // FIXME: this function has not been tested yet uint16 messageSize = inputMessage->getMessageSize() - InputMessage::CHECKSUM_LENGTH; if(messageSize % 8 != 0) { //LOG_TRACE_DEBUG("not valid encrypted message size") return false; } uint32 *buffer = (uint32*)(inputMessage->getBuffer() + InputMessage::DATA_POS); int readPos = 0; while(readPos < messageSize/4) { uint32 v0 = buffer[readPos], v1 = buffer[readPos + 1]; uint32 delta = 0x61C88647; uint32 sum = 0xC6EF3720; for(int32 i = 0; i < 32; i++) { v1 -= ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + m_xteaKey[sum>>11 & 3]); sum += delta; v0 -= ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + m_xteaKey[sum & 3]); } buffer[readPos] = v0; buffer[readPos + 1] = v1; readPos = readPos + 2; } int tmp = inputMessage->getU16(); if(tmp > inputMessage->getMessageSize() - 4) { //LOG_TRACE_DEBUG("not valid unencrypted message size") return false; } inputMessage->setMessageSize(tmp + InputMessage::UNENCRYPTED_DATA_POS); return true; } void Protocol::xteaEncrypt(OutputMessage *outputMessage) { uint16 messageLength = outputMessage->getMessageSize(); //add bytes until reach 8 multiple if((messageLength % 8) != 0) { uint16 n = 8 - (messageLength % 8); outputMessage->addPaddingBytes(n); messageLength += n; } int readPos = 0; uint32 *buffer = (uint32*)outputMessage->getBuffer() + OutputMessage::DATA_POS; while(readPos < messageLength / 4) { uint32 v0 = buffer[readPos], v1 = buffer[readPos + 1]; uint32 delta = 0x61C88647; uint32 sum = 0; for(int32 i = 0; i < 32; i++) { v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + m_xteaKey[sum & 3]); sum -= delta; v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + m_xteaKey[sum>>11 & 3]); } buffer[readPos] = v0; buffer[readPos + 1] = v1; readPos = readPos + 2; } } uint32 Protocol::getAdlerChecksum(uint8 *buffer, uint16 size) { uint32 a = 1, b = 0; while (size > 0) { size_t tlen = size > 5552 ? 5552 : size; size -= tlen; do { a += *buffer++; b += a; } while (--tlen); a %= 65521; b %= 65521; } return (b << 16) | a; }