peerwireclient.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

{
    char buffer[1024];
    qint64 totalRead = 0;
    do {
        qint64 bytesRead = QTcpSocket::readData(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);
}

bool PeerWireClient::canTransferMore() const
{
    return !incomingBuffer.isEmpty() || QTcpSocket::bytesAvailable() > 0
        || !outgoingBuffer.isEmpty() || !pendingBlocks.isEmpty();
}

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();
        }
    } 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 (incomingBuffer.size() < 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 (incomingBuffer.size() < 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 (incomingBuffer.size() < 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 (incomingBuffer.size() < 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 (incomingBuffer.size() > 0);
}

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;
}