tdesktop/Telegram/SourceFiles/mtproto/connection_tcp.cpp

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/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org
Telegram Desktop 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 3 of the License, or
(at your option) any later version.
It 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.
In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.
Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
*/
#include "mtproto/connection_tcp.h"
#include <openssl/aes.h>
namespace MTP {
namespace internal {
namespace {
uint32 tcpPacketSize(const char *packet) { // must have at least 4 bytes readable
uint32 result = (packet[0] > 0) ? packet[0] : 0;
if (result == 0x7f) {
const uchar *bytes = reinterpret_cast<const uchar*>(packet);
result = (((uint32(bytes[3]) << 8) | uint32(bytes[2])) << 8) | uint32(bytes[1]);
return (result << 2) + 4;
}
return (result << 2) + 1;
}
} // namespace
AbstractTCPConnection::AbstractTCPConnection(QThread *thread) : AbstractConnection(thread)
, packetNum(0)
, packetRead(0)
, packetLeft(0)
, readingToShort(true)
, currentPos((char*)shortBuffer) {
}
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AbstractTCPConnection::~AbstractTCPConnection() {
}
void AbstractTCPConnection::socketRead() {
if (sock.state() != QAbstractSocket::ConnectedState) {
LOG(("MTP error: socket not connected in socketRead(), state: %1").arg(sock.state()));
emit error(kErrorCodeOther);
return;
}
do {
uint32 toRead = packetLeft ? packetLeft : (readingToShort ? (MTPShortBufferSize * sizeof(mtpPrime) - packetRead) : 4);
if (readingToShort) {
if (currentPos + toRead > ((char*)shortBuffer) + MTPShortBufferSize * sizeof(mtpPrime)) {
longBuffer.resize(((packetRead + toRead) >> 2) + 1);
memcpy(&longBuffer[0], shortBuffer, packetRead);
currentPos = ((char*)&longBuffer[0]) + packetRead;
readingToShort = false;
}
} else {
if (longBuffer.size() * sizeof(mtpPrime) < packetRead + toRead) {
longBuffer.resize(((packetRead + toRead) >> 2) + 1);
currentPos = ((char*)&longBuffer[0]) + packetRead;
}
}
int32 bytes = (int32)sock.read(currentPos, toRead);
if (bytes > 0) {
aesCtrEncrypt(currentPos, bytes, _receiveKey, &_receiveState);
TCP_LOG(("TCP Info: read %1 bytes").arg(bytes));
packetRead += bytes;
currentPos += bytes;
if (packetLeft) {
packetLeft -= bytes;
if (!packetLeft) {
socketPacket(currentPos - packetRead, packetRead);
currentPos = (char*)shortBuffer;
packetRead = packetLeft = 0;
readingToShort = true;
longBuffer.clear();
} else {
TCP_LOG(("TCP Info: not enough %1 for packet! read %2").arg(packetLeft).arg(packetRead));
emit receivedSome();
}
} else {
bool move = false;
while (packetRead >= 4) {
uint32 packetSize = tcpPacketSize(currentPos - packetRead);
if (packetSize < 5 || packetSize > MTPPacketSizeMax) {
LOG(("TCP Error: packet size = %1").arg(packetSize));
emit error(kErrorCodeOther);
return;
}
if (packetRead >= packetSize) {
socketPacket(currentPos - packetRead, packetSize);
packetRead -= packetSize;
packetLeft = 0;
move = true;
} else {
packetLeft = packetSize - packetRead;
TCP_LOG(("TCP Info: not enough %1 for packet! size %2 read %3").arg(packetLeft).arg(packetSize).arg(packetRead));
emit receivedSome();
break;
}
}
if (move) {
if (!packetRead) {
currentPos = (char*)shortBuffer;
readingToShort = true;
longBuffer.clear();
} else if (!readingToShort && packetRead < MTPShortBufferSize * sizeof(mtpPrime)) {
memcpy(shortBuffer, currentPos - packetRead, packetRead);
currentPos = (char*)shortBuffer + packetRead;
readingToShort = true;
longBuffer.clear();
}
}
}
} else if (bytes < 0) {
LOG(("TCP Error: socket read return -1"));
emit error(kErrorCodeOther);
return;
} else {
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TCP_LOG(("TCP Info: no bytes read, but bytes available was true..."));
break;
}
} while (sock.state() == QAbstractSocket::ConnectedState && sock.bytesAvailable());
}
mtpBuffer AbstractTCPConnection::handleResponse(const char *packet, uint32 length) {
if (length < 5 || length > MTPPacketSizeMax) {
LOG(("TCP Error: bad packet size %1").arg(length));
return mtpBuffer(1, -500);
}
int32 size = packet[0], len = length - 1;
if (size == 0x7f) {
const uchar *bytes = reinterpret_cast<const uchar*>(packet);
size = (((uint32(bytes[3]) << 8) | uint32(bytes[2])) << 8) | uint32(bytes[1]);
len -= 3;
}
if (size * int32(sizeof(mtpPrime)) != len) {
LOG(("TCP Error: bad packet header"));
TCP_LOG(("TCP Error: bad packet header, packet: %1").arg(Logs::mb(packet, length).str()));
return mtpBuffer(1, -500);
}
const mtpPrime *packetdata = reinterpret_cast<const mtpPrime*>(packet + (length - len));
TCP_LOG(("TCP Info: packet received, size = %1").arg(size * sizeof(mtpPrime)));
if (size == 1) {
LOG(("TCP Error: error packet received, code = %1").arg(*packetdata));
return mtpBuffer(1, *packetdata);
}
mtpBuffer data(size);
memcpy(data.data(), packetdata, size * sizeof(mtpPrime));
return data;
}
void AbstractTCPConnection::handleError(QAbstractSocket::SocketError e, QTcpSocket &sock) {
switch (e) {
case QAbstractSocket::ConnectionRefusedError:
LOG(("TCP Error: socket connection refused - %1").arg(sock.errorString()));
break;
case QAbstractSocket::RemoteHostClosedError:
TCP_LOG(("TCP Info: remote host closed socket connection - %1").arg(sock.errorString()));
break;
case QAbstractSocket::HostNotFoundError:
LOG(("TCP Error: host not found - %1").arg(sock.errorString()));
break;
case QAbstractSocket::SocketTimeoutError:
LOG(("TCP Error: socket timeout - %1").arg(sock.errorString()));
break;
case QAbstractSocket::NetworkError:
LOG(("TCP Error: network - %1").arg(sock.errorString()));
break;
case QAbstractSocket::ProxyAuthenticationRequiredError:
case QAbstractSocket::ProxyConnectionRefusedError:
case QAbstractSocket::ProxyConnectionClosedError:
case QAbstractSocket::ProxyConnectionTimeoutError:
case QAbstractSocket::ProxyNotFoundError:
case QAbstractSocket::ProxyProtocolError:
LOG(("TCP Error: proxy (%1) - %2").arg(e).arg(sock.errorString()));
break;
default:
LOG(("TCP Error: other (%1) - %2").arg(e).arg(sock.errorString()));
break;
}
TCP_LOG(("TCP Error %1, restarting! - %2").arg(e).arg(sock.errorString()));
}
TCPConnection::TCPConnection(QThread *thread) : AbstractTCPConnection(thread)
, status(WaitingTcp)
, tcpNonce(rand_value<MTPint128>())
, _tcpTimeout(MTPMinReceiveDelay)
, _flags(0) {
tcpTimeoutTimer.moveToThread(thread);
tcpTimeoutTimer.setSingleShot(true);
connect(&tcpTimeoutTimer, SIGNAL(timeout()), this, SLOT(onTcpTimeoutTimer()));
sock.moveToThread(thread);
App::setProxySettings(sock);
connect(&sock, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(socketError(QAbstractSocket::SocketError)));
connect(&sock, SIGNAL(connected()), this, SLOT(onSocketConnected()));
connect(&sock, SIGNAL(disconnected()), this, SLOT(onSocketDisconnected()));
}
void TCPConnection::onSocketConnected() {
if (status == WaitingTcp) {
mtpBuffer buffer(preparePQFake(tcpNonce));
DEBUG_LOG(("Connection Info: sending fake req_pq through TCP/%1 transport").arg((_flags & MTPDdcOption::Flag::f_ipv6) ? "IPv6" : "IPv4"));
if (_tcpTimeout < 0) _tcpTimeout = -_tcpTimeout;
tcpTimeoutTimer.start(_tcpTimeout);
sendData(buffer);
}
}
void TCPConnection::onTcpTimeoutTimer() {
if (status == WaitingTcp) {
if (_tcpTimeout < MTPMaxReceiveDelay) _tcpTimeout *= 2;
_tcpTimeout = -_tcpTimeout;
QAbstractSocket::SocketState state = sock.state();
if (state == QAbstractSocket::ConnectedState || state == QAbstractSocket::ConnectingState || state == QAbstractSocket::HostLookupState) {
sock.disconnectFromHost();
} else if (state != QAbstractSocket::ClosingState) {
sock.connectToHost(QHostAddress(_addr), _port);
}
}
}
void TCPConnection::onSocketDisconnected() {
if (_tcpTimeout < 0) {
_tcpTimeout = -_tcpTimeout;
if (status == WaitingTcp) {
sock.connectToHost(QHostAddress(_addr), _port);
return;
}
}
if (status == WaitingTcp || status == UsingTcp) {
emit disconnected();
}
}
void TCPConnection::sendData(mtpBuffer &buffer) {
if (status == FinishedWork) return;
if (buffer.size() < 3) {
LOG(("TCP Error: writing bad packet, len = %1").arg(buffer.size() * sizeof(mtpPrime)));
TCP_LOG(("TCP Error: bad packet %1").arg(Logs::mb(&buffer[0], buffer.size() * sizeof(mtpPrime)).str()));
emit error(kErrorCodeOther);
return;
}
tcpSend(buffer);
}
void AbstractTCPConnection::tcpSend(mtpBuffer &buffer) {
if (!packetNum) {
// prepare random part
char nonce[64];
uint32 *first = reinterpret_cast<uint32*>(nonce), *second = first + 1;
uint32 first1 = 0x44414548U, first2 = 0x54534f50U, first3 = 0x20544547U, first4 = 0x20544547U, first5 = 0xeeeeeeeeU;
uint32 second1 = 0;
do {
memset_rand(nonce, sizeof(nonce));
} while (*first == first1 || *first == first2 || *first == first3 || *first == first4 || *first == first5 || *second == second1 || *reinterpret_cast<uchar*>(nonce) == 0xef);
//sock.write(nonce, 64);
// prepare encryption key/iv
memcpy(_sendKey, nonce + 8, CTRState::KeySize);
memcpy(_sendState.ivec, nonce + 8 + CTRState::KeySize, CTRState::IvecSize);
// prepare decryption key/iv
char reversed[48];
memcpy(reversed, nonce + 8, sizeof(reversed));
std::reverse(reversed, reversed + base::array_size(reversed));
memcpy(_receiveKey, reversed, CTRState::KeySize);
memcpy(_receiveState.ivec, reversed + CTRState::KeySize, CTRState::IvecSize);
// write protocol identifier
*reinterpret_cast<uint32*>(nonce + 56) = 0xefefefefU;
sock.write(nonce, 56);
aesCtrEncrypt(nonce, 64, _sendKey, &_sendState);
sock.write(nonce + 56, 8);
}
++packetNum;
uint32 size = buffer.size() - 3, len = size * 4;
char *data = reinterpret_cast<char*>(&buffer[0]);
if (size < 0x7f) {
data[7] = char(size);
TCP_LOG(("TCP Info: write %1 packet %2").arg(packetNum).arg(len + 1));
aesCtrEncrypt(data + 7, len + 1, _sendKey, &_sendState);
sock.write(data + 7, len + 1);
} else {
data[4] = 0x7f;
reinterpret_cast<uchar*>(data)[5] = uchar(size & 0xFF);
reinterpret_cast<uchar*>(data)[6] = uchar((size >> 8) & 0xFF);
reinterpret_cast<uchar*>(data)[7] = uchar((size >> 16) & 0xFF);
TCP_LOG(("TCP Info: write %1 packet %2").arg(packetNum).arg(len + 4));
aesCtrEncrypt(data + 4, len + 4, _sendKey, &_sendState);
sock.write(data + 4, len + 4);
}
}
void TCPConnection::disconnectFromServer() {
if (status == FinishedWork) return;
status = FinishedWork;
disconnect(&sock, SIGNAL(readyRead()), 0, 0);
sock.close();
}
void TCPConnection::connectTcp(const DcOptions::Endpoint &endpoint) {
_addr = QString::fromStdString(endpoint.ip);
_port = endpoint.port;
_flags = endpoint.flags;
connect(&sock, SIGNAL(readyRead()), this, SLOT(socketRead()));
sock.connectToHost(QHostAddress(_addr), _port);
}
void TCPConnection::socketPacket(const char *packet, uint32 length) {
if (status == FinishedWork) return;
mtpBuffer data = handleResponse(packet, length);
if (data.size() == 1) {
emit error(data[0]);
} else if (status == UsingTcp) {
_receivedQueue.push_back(data);
emit receivedData();
} else if (status == WaitingTcp) {
tcpTimeoutTimer.stop();
try {
auto res_pq = readPQFakeReply(data);
const auto &res_pq_data(res_pq.c_resPQ());
if (res_pq_data.vnonce == tcpNonce) {
DEBUG_LOG(("Connection Info: TCP/%1-transport chosen by pq-response").arg((_flags & MTPDdcOption::Flag::f_ipv6) ? "IPv6" : "IPv4"));
status = UsingTcp;
emit connected();
}
} catch (Exception &e) {
DEBUG_LOG(("Connection Error: exception in parsing TCP fake pq-responce, %1").arg(e.what()));
emit error(kErrorCodeOther);
}
}
}
bool TCPConnection::isConnected() const {
return (status == UsingTcp);
}
int32 TCPConnection::debugState() const {
return sock.state();
}
QString TCPConnection::transport() const {
return isConnected() ? qsl("TCP") : QString();
}
void TCPConnection::socketError(QAbstractSocket::SocketError e) {
if (status == FinishedWork) return;
handleError(e, sock);
emit error(kErrorCodeOther);
}
} // namespace internal
} // namespace MTP