qt5base-lts/examples/network/torrent/peerwireclient.cpp
Jani Heikkinen cd46a2daf5 Unify license header usage.
Update files using old header.LGPL3 to header.LGPL
Update files using old FDL template to use new one
Update files using old BSD template to use new one

Change-Id: I36a78272516f9953d02956522f285b40adfc8915
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
2016-03-29 10:20:03 +00:00

674 lines
21 KiB
C++

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
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** as follows:
**
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** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
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****************************************************************************/
#include "peerwireclient.h"
#include <QHostAddress>
#include <QTimerEvent>
static const int PendingRequestTimeout = 60 * 1000;
static const int ClientTimeout = 120 * 1000;
static const int ConnectTimeout = 60 * 1000;
static const int KeepAliveInterval = 30 * 1000;
static const int RateControlTimerDelay = 2000;
static const int MinimalHeaderSize = 48;
static const char ProtocolId[] = "BitTorrent protocol";
static const char ProtocolIdSize = 19;
// Reads a 32bit unsigned int from data in network order.
static inline quint32 fromNetworkData(const char *data)
{
const unsigned char *udata = (const unsigned char *)data;
return (quint32(udata[0]) << 24)
| (quint32(udata[1]) << 16)
| (quint32(udata[2]) << 8)
| (quint32(udata[3]));
}
// Writes a 32bit unsigned int from num to data in network order.
static inline void toNetworkData(quint32 num, char *data)
{
unsigned char *udata = (unsigned char *)data;
udata[3] = (num & 0xff);
udata[2] = (num & 0xff00) >> 8;
udata[1] = (num & 0xff0000) >> 16;
udata[0] = (num & 0xff000000) >> 24;
}
// Constructs an unconnected PeerWire client and starts the connect timer.
PeerWireClient::PeerWireClient(const QByteArray &peerId, QObject *parent)
: QTcpSocket(parent), pendingBlockSizes(0),
pwState(ChokingPeer | ChokedByPeer), receivedHandShake(false), gotPeerId(false),
sentHandShake(false), nextPacketLength(-1), pendingRequestTimer(0), invalidateTimeout(false),
keepAliveTimer(0), torrentPeer(0)
{
memset(uploadSpeedData, 0, sizeof(uploadSpeedData));
memset(downloadSpeedData, 0, sizeof(downloadSpeedData));
transferSpeedTimer = startTimer(RateControlTimerDelay);
timeoutTimer = startTimer(ConnectTimeout);
peerIdString = peerId;
connect(this, SIGNAL(readyRead()), this, SIGNAL(readyToTransfer()));
connect(this, SIGNAL(connected()), this, SIGNAL(readyToTransfer()));
connect(&socket, SIGNAL(connected()),
this, SIGNAL(connected()));
connect(&socket, SIGNAL(readyRead()),
this, SIGNAL(readyRead()));
connect(&socket, SIGNAL(disconnected()),
this, SIGNAL(disconnected()));
connect(&socket, SIGNAL(error(QAbstractSocket::SocketError)),
this, SIGNAL(error(QAbstractSocket::SocketError)));
connect(&socket, SIGNAL(bytesWritten(qint64)),
this, SIGNAL(bytesWritten(qint64)));
connect(&socket, SIGNAL(stateChanged(QAbstractSocket::SocketState)),
this, SLOT(socketStateChanged(QAbstractSocket::SocketState)));
}
// Registers the peer ID and SHA1 sum of the torrent, and initiates
// the handshake.
void PeerWireClient::initialize(const QByteArray &infoHash, int pieceCount)
{
this->infoHash = infoHash;
peerPieces.resize(pieceCount);
if (!sentHandShake)
sendHandShake();
}
void PeerWireClient::setPeer(TorrentPeer *peer)
{
torrentPeer = peer;
}
TorrentPeer *PeerWireClient::peer() const
{
return torrentPeer;
}
QBitArray PeerWireClient::availablePieces() const
{
return peerPieces;
}
QList<TorrentBlock> PeerWireClient::incomingBlocks() const
{
return incoming;
}
// Sends a "choke" message, asking the peer to stop requesting blocks.
void PeerWireClient::chokePeer()
{
const char message[] = {0, 0, 0, 1, 0};
write(message, sizeof(message));
pwState |= ChokingPeer;
// After receiving a choke message, the peer will assume all
// pending requests are lost.
pendingBlocks.clear();
pendingBlockSizes = 0;
}
// Sends an "unchoke" message, allowing the peer to start/resume
// requesting blocks.
void PeerWireClient::unchokePeer()
{
const char message[] = {0, 0, 0, 1, 1};
write(message, sizeof(message));
pwState &= ~ChokingPeer;
if (pendingRequestTimer)
killTimer(pendingRequestTimer);
}
// Sends a "keep-alive" message to prevent the peer from closing
// the connection when there's no activity
void PeerWireClient::sendKeepAlive()
{
const char message[] = {0, 0, 0, 0};
write(message, sizeof(message));
}
// Sends an "interested" message, informing the peer that it has got
// pieces that we'd like to download.
void PeerWireClient::sendInterested()
{
const char message[] = {0, 0, 0, 1, 2};
write(message, sizeof(message));
pwState |= InterestedInPeer;
// After telling the peer that we're interested, we expect to get
// unchoked within a certain timeframe; otherwise we'll drop the
// connection.
if (pendingRequestTimer)
killTimer(pendingRequestTimer);
pendingRequestTimer = startTimer(PendingRequestTimeout);
}
// Sends a "not interested" message, informing the peer that it does
// not have any pieces that we'd like to download.
void PeerWireClient::sendNotInterested()
{
const char message[] = {0, 0, 0, 1, 3};
write(message, sizeof(message));
pwState &= ~InterestedInPeer;
}
// Sends a piece notification / a "have" message, informing the peer
// that we have just downloaded a new piece.
void PeerWireClient::sendPieceNotification(int piece)
{
if (!sentHandShake)
sendHandShake();
char message[] = {0, 0, 0, 5, 4, 0, 0, 0, 0};
toNetworkData(piece, &message[5]);
write(message, sizeof(message));
}
// Sends the complete list of pieces that we have downloaded.
void PeerWireClient::sendPieceList(const QBitArray &bitField)
{
// The bitfield message may only be sent immediately after the
// handshaking sequence is completed, and before any other
// messages are sent.
if (!sentHandShake)
sendHandShake();
// Don't send the bitfield if it's all zeros.
if (bitField.count(true) == 0)
return;
int bitFieldSize = bitField.size();
int size = (bitFieldSize + 7) / 8;
QByteArray bits(size, '\0');
for (int i = 0; i < bitFieldSize; ++i) {
if (bitField.testBit(i)) {
quint32 byte = quint32(i) / 8;
quint32 bit = quint32(i) % 8;
bits[byte] = uchar(bits.at(byte)) | (1 << (7 - bit));
}
}
char message[] = {0, 0, 0, 1, 5};
toNetworkData(bits.size() + 1, &message[0]);
write(message, sizeof(message));
write(bits);
}
// Sends a request for a block.
void PeerWireClient::requestBlock(int piece, int offset, int length)
{
char message[] = {0, 0, 0, 1, 6};
toNetworkData(13, &message[0]);
write(message, sizeof(message));
char numbers[4 * 3];
toNetworkData(piece, &numbers[0]);
toNetworkData(offset, &numbers[4]);
toNetworkData(length, &numbers[8]);
write(numbers, sizeof(numbers));
incoming << TorrentBlock(piece, offset, length);
// After requesting a block, we expect the block to be sent by the
// other peer within a certain number of seconds. Otherwise, we
// drop the connection.
if (pendingRequestTimer)
killTimer(pendingRequestTimer);
pendingRequestTimer = startTimer(PendingRequestTimeout);
}
// Cancels a request for a block.
void PeerWireClient::cancelRequest(int piece, int offset, int length)
{
char message[] = {0, 0, 0, 1, 8};
toNetworkData(13, &message[0]);
write(message, sizeof(message));
char numbers[4 * 3];
toNetworkData(piece, &numbers[0]);
toNetworkData(offset, &numbers[4]);
toNetworkData(length, &numbers[8]);
write(numbers, sizeof(numbers));
incoming.removeAll(TorrentBlock(piece, offset, length));
}
// Sends a block to the peer.
void PeerWireClient::sendBlock(int piece, int offset, const QByteArray &data)
{
QByteArray block;
char message[] = {0, 0, 0, 1, 7};
toNetworkData(9 + data.size(), &message[0]);
block += QByteArray(message, sizeof(message));
char numbers[4 * 2];
toNetworkData(piece, &numbers[0]);
toNetworkData(offset, &numbers[4]);
block += QByteArray(numbers, sizeof(numbers));
block += data;
BlockInfo blockInfo;
blockInfo.pieceIndex = piece;
blockInfo.offset = offset;
blockInfo.length = data.size();
blockInfo.block = block;
pendingBlocks << blockInfo;
pendingBlockSizes += block.size();
if (pendingBlockSizes > 32 * 16384) {
chokePeer();
unchokePeer();
return;
}
emit readyToTransfer();
}
// Attempts to write 'bytes' bytes to the socket from the buffer.
// This is used by RateController, which precisely controls how much
// each client can write.
qint64 PeerWireClient::writeToSocket(qint64 bytes)
{
qint64 totalWritten = 0;
do {
if (outgoingBuffer.isEmpty() && !pendingBlocks.isEmpty()) {
BlockInfo block = pendingBlocks.takeFirst();
pendingBlockSizes -= block.length;
outgoingBuffer += block.block;
}
qint64 written = socket.write(outgoingBuffer.constData(),
qMin<qint64>(bytes - totalWritten, outgoingBuffer.size()));
if (written <= 0)
return totalWritten ? totalWritten : written;
totalWritten += written;
uploadSpeedData[0] += written;
outgoingBuffer.remove(0, written);
} while (totalWritten < bytes && (!outgoingBuffer.isEmpty() || !pendingBlocks.isEmpty()));
return totalWritten;
}
// Attempts to read at most 'bytes' bytes from the socket.
qint64 PeerWireClient::readFromSocket(qint64 bytes)
{
char buffer[1024];
qint64 totalRead = 0;
do {
qint64 bytesRead = socket.read(buffer, qMin<qint64>(sizeof(buffer), bytes - totalRead));
if (bytesRead <= 0)
break;
qint64 oldSize = incomingBuffer.size();
incomingBuffer.resize(oldSize + bytesRead);
memcpy(incomingBuffer.data() + oldSize, buffer, bytesRead);
totalRead += bytesRead;
} while (totalRead < bytes);
if (totalRead > 0) {
downloadSpeedData[0] += totalRead;
emit bytesReceived(totalRead);
processIncomingData();
}
return totalRead;
}
// Returns the average number of bytes per second this client is
// downloading.
qint64 PeerWireClient::downloadSpeed() const
{
qint64 sum = 0;
for (unsigned int i = 0; i < sizeof(downloadSpeedData) / sizeof(qint64); ++i)
sum += downloadSpeedData[i];
return sum / (8 * 2);
}
// Returns the average number of bytes per second this client is
// uploading.
qint64 PeerWireClient::uploadSpeed() const
{
qint64 sum = 0;
for (unsigned int i = 0; i < sizeof(uploadSpeedData) / sizeof(qint64); ++i)
sum += uploadSpeedData[i];
return sum / (8 * 2);
}
void PeerWireClient::setReadBufferSize(qint64 size)
{
socket.setReadBufferSize(size);
}
bool PeerWireClient::canTransferMore() const
{
return bytesAvailable() > 0 || socket.bytesAvailable() > 0
|| !outgoingBuffer.isEmpty() || !pendingBlocks.isEmpty();
}
void PeerWireClient::connectToHost(const QHostAddress &address,
quint16 port, OpenMode openMode)
{
setOpenMode(openMode);
socket.connectToHost(address, port, openMode);
}
void PeerWireClient::diconnectFromHost()
{
socket.disconnectFromHost();
}
void PeerWireClient::timerEvent(QTimerEvent *event)
{
if (event->timerId() == transferSpeedTimer) {
// Rotate the upload / download records.
for (int i = 6; i >= 0; --i) {
uploadSpeedData[i + 1] = uploadSpeedData[i];
downloadSpeedData[i + 1] = downloadSpeedData[i];
}
uploadSpeedData[0] = 0;
downloadSpeedData[0] = 0;
} else if (event->timerId() == timeoutTimer) {
// Disconnect if we timed out; otherwise the timeout is
// restarted.
if (invalidateTimeout) {
invalidateTimeout = false;
} else {
abort();
emit infoHashReceived(QByteArray());
}
} else if (event->timerId() == pendingRequestTimer) {
abort();
} else if (event->timerId() == keepAliveTimer) {
sendKeepAlive();
}
QTcpSocket::timerEvent(event);
}
// Sends the handshake to the peer.
void PeerWireClient::sendHandShake()
{
sentHandShake = true;
// Restart the timeout
if (timeoutTimer)
killTimer(timeoutTimer);
timeoutTimer = startTimer(ClientTimeout);
// Write the 68 byte PeerWire handshake.
write(&ProtocolIdSize, 1);
write(ProtocolId, ProtocolIdSize);
write(QByteArray(8, '\0'));
write(infoHash);
write(peerIdString);
}
void PeerWireClient::processIncomingData()
{
invalidateTimeout = true;
if (!receivedHandShake) {
// Check that we received enough data
if (bytesAvailable() < MinimalHeaderSize)
return;
// Sanity check the protocol ID
QByteArray id = read(ProtocolIdSize + 1);
if (id.at(0) != ProtocolIdSize || !id.mid(1).startsWith(ProtocolId)) {
abort();
return;
}
// Discard 8 reserved bytes, then read the info hash and peer ID
(void) read(8);
// Read infoHash
QByteArray peerInfoHash = read(20);
if (!infoHash.isEmpty() && peerInfoHash != infoHash) {
abort();
return;
}
emit infoHashReceived(peerInfoHash);
if (infoHash.isEmpty()) {
abort();
return;
}
// Send handshake
if (!sentHandShake)
sendHandShake();
receivedHandShake = true;
}
// Handle delayed peer id arrival
if (!gotPeerId) {
if (bytesAvailable() < 20)
return;
gotPeerId = true;
if (read(20) == peerIdString) {
// We connected to ourself
abort();
return;
}
}
// Initialize keep-alive timer
if (!keepAliveTimer)
keepAliveTimer = startTimer(KeepAliveInterval);
do {
// Find the packet length
if (nextPacketLength == -1) {
if (bytesAvailable() < 4)
return;
char tmp[4];
read(tmp, sizeof(tmp));
nextPacketLength = fromNetworkData(tmp);
if (nextPacketLength < 0 || nextPacketLength > 200000) {
// Prevent DoS
abort();
return;
}
}
// KeepAlive
if (nextPacketLength == 0) {
nextPacketLength = -1;
continue;
}
// Wait with parsing until the whole packet has been received
if (bytesAvailable() < nextPacketLength)
return;
// Read the packet
QByteArray packet = read(nextPacketLength);
if (packet.size() != nextPacketLength) {
abort();
return;
}
switch (packet.at(0)) {
case ChokePacket:
// We have been choked.
pwState |= ChokedByPeer;
incoming.clear();
if (pendingRequestTimer)
killTimer(pendingRequestTimer);
emit choked();
break;
case UnchokePacket:
// We have been unchoked.
pwState &= ~ChokedByPeer;
emit unchoked();
break;
case InterestedPacket:
// The peer is interested in downloading.
pwState |= PeerIsInterested;
emit interested();
break;
case NotInterestedPacket:
// The peer is not interested in downloading.
pwState &= ~PeerIsInterested;
emit notInterested();
break;
case HavePacket: {
// The peer has a new piece available.
quint32 index = fromNetworkData(&packet.data()[1]);
if (index < quint32(peerPieces.size())) {
// Only accept indexes within the valid range.
peerPieces.setBit(int(index));
}
emit piecesAvailable(availablePieces());
break;
}
case BitFieldPacket:
// The peer has the following pieces available.
for (int i = 1; i < packet.size(); ++i) {
for (int bit = 0; bit < 8; ++bit) {
if (packet.at(i) & (1 << (7 - bit))) {
int bitIndex = int(((i - 1) * 8) + bit);
if (bitIndex >= 0 && bitIndex < peerPieces.size()) {
// Occasionally, broken clients claim to have
// pieces whose index is outside the valid range.
// The most common mistake is the index == size
// case.
peerPieces.setBit(bitIndex);
}
}
}
}
emit piecesAvailable(availablePieces());
break;
case RequestPacket: {
// The peer requests a block.
quint32 index = fromNetworkData(&packet.data()[1]);
quint32 begin = fromNetworkData(&packet.data()[5]);
quint32 length = fromNetworkData(&packet.data()[9]);
emit blockRequested(int(index), int(begin), int(length));
break;
}
case PiecePacket: {
int index = int(fromNetworkData(&packet.data()[1]));
int begin = int(fromNetworkData(&packet.data()[5]));
incoming.removeAll(TorrentBlock(index, begin, packet.size() - 9));
// The peer sends a block.
emit blockReceived(index, begin, packet.mid(9));
// Kill the pending block timer.
if (pendingRequestTimer) {
killTimer(pendingRequestTimer);
pendingRequestTimer = 0;
}
break;
}
case CancelPacket: {
// The peer cancels a block request.
quint32 index = fromNetworkData(&packet.data()[1]);
quint32 begin = fromNetworkData(&packet.data()[5]);
quint32 length = fromNetworkData(&packet.data()[9]);
for (int i = 0; i < pendingBlocks.size(); ++i) {
const BlockInfo &blockInfo = pendingBlocks.at(i);
if (blockInfo.pieceIndex == int(index)
&& blockInfo.offset == int(begin)
&& blockInfo.length == int(length)) {
pendingBlocks.removeAt(i);
break;
}
}
break;
}
default:
// Unsupported packet type; just ignore it.
break;
}
nextPacketLength = -1;
} while (bytesAvailable() > 0);
}
void PeerWireClient::socketStateChanged(QAbstractSocket::SocketState state)
{
setLocalAddress(socket.localAddress());
setLocalPort(socket.localPort());
setPeerName(socket.peerName());
setPeerAddress(socket.peerAddress());
setPeerPort(socket.peerPort());
setSocketState(state);
}
qint64 PeerWireClient::readData(char *data, qint64 size)
{
int n = qMin<int>(size, incomingBuffer.size());
memcpy(data, incomingBuffer.constData(), n);
incomingBuffer.remove(0, n);
return n;
}
qint64 PeerWireClient::readLineData(char *data, qint64 maxlen)
{
return QIODevice::readLineData(data, maxlen);
}
qint64 PeerWireClient::writeData(const char *data, qint64 size)
{
int oldSize = outgoingBuffer.size();
outgoingBuffer.resize(oldSize + size);
memcpy(outgoingBuffer.data() + oldSize, data, size);
emit readyToTransfer();
return size;
}