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Diffstat (limited to 'examples/network/torrent/peerwireclient.cpp')
| -rw-r--r-- | examples/network/torrent/peerwireclient.cpp | 665 |
1 files changed, 665 insertions, 0 deletions
diff --git a/examples/network/torrent/peerwireclient.cpp b/examples/network/torrent/peerwireclient.cpp new file mode 100644 index 0000000..e79184b --- /dev/null +++ b/examples/network/torrent/peerwireclient.cpp @@ -0,0 +1,665 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the examples of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#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 int FullHeaderSize = 68; +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(int size) +{ + socket.setReadBufferSize(size); +} + +bool PeerWireClient::canTransferMore() const +{ + return bytesAvailable() > 0 || socket.bytesAvailable() > 0 + || !outgoingBuffer.isEmpty() || !pendingBlocks.isEmpty(); +} + +void PeerWireClient::connectToHostImplementation(const QString &hostName, + quint16 port, OpenMode openMode) + +{ + setOpenMode(openMode); + socket.connectToHost(hostName, port, openMode); +} + +void PeerWireClient::diconnectFromHostImplementation() +{ + 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; +} |