network.cpp

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// network.cpp - written and placed in the public domain by Wei Dai

#include "pch.h"

#include "network.h"

#if !defined(NO_OS_DEPENDENCE) && defined(SOCKETS_AVAILABLE)

#include "wait.h"

#define CRYPTOPP_TRACE_NETWORK 0

NAMESPACE_BEGIN(CryptoPP)

lword LimitedBandwidth::ComputeCurrentTransceiveLimit()
{
        if (!m_maxBytesPerSecond)
                return ULONG_MAX;

        const double curTime = GetCurTimeAndCleanUp();
        CRYPTOPP_UNUSED(curTime);

        lword total = 0;
        for (OpQueue::size_type i=0; i!=m_ops.size(); ++i)
                total += m_ops[i].second;
        return SaturatingSubtract(m_maxBytesPerSecond, total);
}

double LimitedBandwidth::TimeToNextTransceive()
{
        if (!m_maxBytesPerSecond)
                return 0;

        if (!m_nextTransceiveTime)
                ComputeNextTransceiveTime();

        return SaturatingSubtract(m_nextTransceiveTime, m_timer.ElapsedTimeAsDouble());
}

void LimitedBandwidth::NoteTransceive(lword size)
{
        if (m_maxBytesPerSecond)
        {
                double curTime = GetCurTimeAndCleanUp();
                m_ops.push_back(std::make_pair(curTime, size));
                m_nextTransceiveTime = 0;
        }
}

void LimitedBandwidth::ComputeNextTransceiveTime()
{
        double curTime = GetCurTimeAndCleanUp();
        lword total = 0;
        for (unsigned int i=0; i!=m_ops.size(); ++i)
                total += m_ops[i].second;
        m_nextTransceiveTime =
                (total < m_maxBytesPerSecond) ? curTime : m_ops.front().first + 1000;
}

double LimitedBandwidth::GetCurTimeAndCleanUp()
{
        if (!m_maxBytesPerSecond)
                return 0;

        double curTime = m_timer.ElapsedTimeAsDouble();
        while (m_ops.size() && (m_ops.front().first + 1000 < curTime))
                m_ops.pop_front();
        return curTime;
}

void LimitedBandwidth::GetWaitObjects(WaitObjectContainer &container, const CallStack &callStack)
{
        double nextTransceiveTime = TimeToNextTransceive();
        if (nextTransceiveTime)
                container.ScheduleEvent(nextTransceiveTime, CallStack("LimitedBandwidth::GetWaitObjects()", &callStack));
}

// *************************************************************

size_t NonblockingSource::GeneralPump2(
        lword& byteCount, bool blockingOutput,
        unsigned long maxTime, bool checkDelimiter, byte delimiter)
{
        m_blockedBySpeedLimit = false;

        if (!GetMaxBytesPerSecond())
        {
                size_t ret = DoPump(byteCount, blockingOutput, maxTime, checkDelimiter, delimiter);
                m_doPumpBlocked = (ret != 0);
                return ret;
        }

        bool forever = (maxTime == INFINITE_TIME);
        unsigned long timeToGo = maxTime;
        Timer timer(Timer::MILLISECONDS, forever);
        lword maxSize = byteCount;
        byteCount = 0;

        timer.StartTimer();

        while (true)
        {
                lword curMaxSize = UnsignedMin(ComputeCurrentTransceiveLimit(), maxSize - byteCount);

                if (curMaxSize || m_doPumpBlocked)
                {
                        if (!forever) timeToGo = SaturatingSubtract(maxTime, timer.ElapsedTime());
                        size_t ret = DoPump(curMaxSize, blockingOutput, timeToGo, checkDelimiter, delimiter);
                        m_doPumpBlocked = (ret != 0);
                        if (curMaxSize)
                        {
                                NoteTransceive(curMaxSize);
                                byteCount += curMaxSize;
                        }
                        if (ret)
                                return ret;
                }

                if (maxSize != ULONG_MAX && byteCount >= maxSize)
                        break;

                if (!forever)
                {
                        timeToGo = SaturatingSubtract(maxTime, timer.ElapsedTime());
                        if (!timeToGo)
                                break;
                }

                double waitTime = TimeToNextTransceive();
                if (!forever && waitTime > timeToGo)
                {
                        m_blockedBySpeedLimit = true;
                        break;
                }

                WaitObjectContainer container;
                LimitedBandwidth::GetWaitObjects(container, CallStack("NonblockingSource::GeneralPump2() - speed limit", 0));
                container.Wait((unsigned long)waitTime);
        }

        return 0;
}

size_t NonblockingSource::PumpMessages2(unsigned int &messageCount, bool blocking)
{
        if (messageCount == 0)
                return 0;

        messageCount = 0;

        lword byteCount;
        do {
                byteCount = LWORD_MAX;
                RETURN_IF_NONZERO(Pump2(byteCount, blocking));
        } while(byteCount == LWORD_MAX);

        if (!m_messageEndSent && SourceExhausted())
        {
                RETURN_IF_NONZERO(AttachedTransformation()->Put2(NULL, 0, GetAutoSignalPropagation(), true));
                m_messageEndSent = true;
                messageCount = 1;
        }
        return 0;
}

lword NonblockingSink::TimedFlush(unsigned long maxTime, size_t targetSize)
{
        m_blockedBySpeedLimit = false;

        size_t curBufSize = GetCurrentBufferSize();
        if (curBufSize <= targetSize && (targetSize || !EofPending()))
                return 0;

        if (!GetMaxBytesPerSecond())
                return DoFlush(maxTime, targetSize);

        bool forever = (maxTime == INFINITE_TIME);
        unsigned long timeToGo = maxTime;
        Timer timer(Timer::MILLISECONDS, forever);
        lword totalFlushed = 0;

        timer.StartTimer();

        while (true)
        {
                size_t flushSize = UnsignedMin(curBufSize - targetSize, ComputeCurrentTransceiveLimit());
                if (flushSize || EofPending())
                {
                        if (!forever) timeToGo = SaturatingSubtract(maxTime, timer.ElapsedTime());
                        size_t ret = (size_t)DoFlush(timeToGo, curBufSize - flushSize);
                        if (ret)
                        {
                                NoteTransceive(ret);
                                curBufSize -= ret;
                                totalFlushed += ret;
                        }
                }

                if (curBufSize <= targetSize && (targetSize || !EofPending()))
                        break;

                if (!forever)
                {
                        timeToGo = SaturatingSubtract(maxTime, timer.ElapsedTime());
                        if (!timeToGo)
                                break;
                }

                double waitTime = TimeToNextTransceive();
                if (!forever && waitTime > timeToGo)
                {
                        m_blockedBySpeedLimit = true;
                        break;
                }

                WaitObjectContainer container;
                LimitedBandwidth::GetWaitObjects(container, CallStack("NonblockingSink::TimedFlush() - speed limit", 0));
                container.Wait((unsigned long)waitTime);
        }

        return totalFlushed;
}

bool NonblockingSink::IsolatedFlush(bool hardFlush, bool blocking)
{
        TimedFlush(blocking ? INFINITE_TIME : 0);
        return hardFlush && (!!GetCurrentBufferSize() || EofPending());
}

// *************************************************************

NetworkSource::NetworkSource(BufferedTransformation *attachment)
        : NonblockingSource(attachment), m_buf(1024*16)
        ,  m_putSize(0), m_dataBegin(0), m_dataEnd(0)
        ,  m_waitingForResult(false), m_outputBlocked(false)
{
}

unsigned int NetworkSource::GetMaxWaitObjectCount() const
{
        return LimitedBandwidth::GetMaxWaitObjectCount()
                + GetReceiver().GetMaxWaitObjectCount()
                + AttachedTransformation()->GetMaxWaitObjectCount();
}

void NetworkSource::GetWaitObjects(WaitObjectContainer &container, CallStack const& callStack)
{
        if (BlockedBySpeedLimit())
                LimitedBandwidth::GetWaitObjects(container, CallStack("NetworkSource::GetWaitObjects() - speed limit", &callStack));
        else if (!m_outputBlocked)
        {
                if (m_dataBegin == m_dataEnd)
                        AccessReceiver().GetWaitObjects(container, CallStack("NetworkSource::GetWaitObjects() - no data", &callStack));
                else
                        container.SetNoWait(CallStack("NetworkSource::GetWaitObjects() - have data", &callStack));
        }

        AttachedTransformation()->GetWaitObjects(container, CallStack("NetworkSource::GetWaitObjects() - attachment", &callStack));
}

size_t NetworkSource::DoPump(lword &byteCount, bool blockingOutput, unsigned long maxTime, bool checkDelimiter, byte delimiter)
{
        NetworkReceiver &receiver = AccessReceiver();

        lword maxSize = byteCount;
        byteCount = 0;
        bool forever = maxTime == INFINITE_TIME;
        Timer timer(Timer::MILLISECONDS, forever);
        BufferedTransformation *t = AttachedTransformation();

        if (m_outputBlocked)
                goto DoOutput;

        while (true)
        {
                if (m_dataBegin == m_dataEnd)
                {
                        if (receiver.EofReceived())
                                break;

                        if (m_waitingForResult)
                        {
                                if (receiver.MustWaitForResult() &&
                                        !receiver.Wait(SaturatingSubtract(maxTime, timer.ElapsedTime()),
                                                CallStack("NetworkSource::DoPump() - wait receive result", 0)))
                                        break;

                                unsigned int recvResult = receiver.GetReceiveResult();
#if CRYPTOPP_TRACE_NETWORK
                                OutputDebugString((IntToString((unsigned int)this) + ": Received " + IntToString(recvResult) + " bytes\n").c_str());
#endif
                                m_dataEnd += recvResult;
                                m_waitingForResult = false;

                                if (!receiver.MustWaitToReceive() && !receiver.EofReceived() && m_dataEnd != m_buf.size())
                                        goto ReceiveNoWait;
                        }
                        else
                        {
                                m_dataEnd = m_dataBegin = 0;

                                if (receiver.MustWaitToReceive())
                                {
                                        if (!receiver.Wait(SaturatingSubtract(maxTime, timer.ElapsedTime()),
                                                        CallStack("NetworkSource::DoPump() - wait receive", 0)))
                                                break;

                                        receiver.Receive(m_buf+m_dataEnd, m_buf.size()-m_dataEnd);
                                        m_waitingForResult = true;
                                }
                                else
                                {
ReceiveNoWait:
                                        m_waitingForResult = true;
                                        // call Receive repeatedly as long as data is immediately available,
                                        // because some receivers tend to return data in small pieces
#if CRYPTOPP_TRACE_NETWORK
                                        OutputDebugString((IntToString((unsigned int)this) + ": Receiving " + IntToString(m_buf.size()-m_dataEnd) + " bytes\n").c_str());
#endif
                                        while (receiver.Receive(m_buf+m_dataEnd, m_buf.size()-m_dataEnd))
                                        {
                                                unsigned int recvResult = receiver.GetReceiveResult();
#if CRYPTOPP_TRACE_NETWORK
                                                OutputDebugString((IntToString((unsigned int)this) + ": Received " + IntToString(recvResult) + " bytes\n").c_str());
#endif
                                                m_dataEnd += recvResult;
                                                if (receiver.EofReceived() || m_dataEnd > m_buf.size() /2)
                                                {
                                                        m_waitingForResult = false;
                                                        break;
                                                }
                                        }
                                }
                        }
                }
                else
                {
                        m_putSize = UnsignedMin(m_dataEnd - m_dataBegin, maxSize - byteCount);

                        if (checkDelimiter)
                                m_putSize = std::find(m_buf+m_dataBegin, m_buf+m_dataBegin+m_putSize, delimiter) - (m_buf+m_dataBegin);

DoOutput:
                        size_t result = t->PutModifiable2(m_buf+m_dataBegin, m_putSize, 0, forever || blockingOutput);
                        if (result)
                        {
                                if (t->Wait(SaturatingSubtract(maxTime, timer.ElapsedTime()),
                                                CallStack("NetworkSource::DoPump() - wait attachment", 0)))
                                        goto DoOutput;
                                else
                                {
                                        m_outputBlocked = true;
                                        return result;
                                }
                        }
                        m_outputBlocked = false;

                        byteCount += m_putSize;
                        m_dataBegin += m_putSize;
                        if (checkDelimiter && m_dataBegin < m_dataEnd && m_buf[m_dataBegin] == delimiter)
                                break;
                        if (maxSize != ULONG_MAX && byteCount == maxSize)
                                break;
                        // once time limit is reached, return even if there is more data waiting
                        // but make 0 a special case so caller can request a large amount of data to be
                        // pumped as long as it is immediately available
                        if (maxTime > 0 && timer.ElapsedTime() > maxTime)
                                break;
                }
        }

        return 0;
}

// *************************************************************

NetworkSink::NetworkSink(unsigned int maxBufferSize, unsigned int autoFlushBound)
        : m_maxBufferSize(maxBufferSize), m_autoFlushBound(autoFlushBound)
        , m_needSendResult(false), m_wasBlocked(false), m_eofState(EOF_NONE)
        , m_buffer(STDMIN(16U*1024U+256, maxBufferSize)), m_skipBytes(0)
        , m_speedTimer(Timer::MILLISECONDS), m_byteCountSinceLastTimerReset(0)
        , m_currentSpeed(0), m_maxObservedSpeed(0)
{
}

float NetworkSink::ComputeCurrentSpeed()
{
        if (m_speedTimer.ElapsedTime() > 1000)
        {
                m_currentSpeed = m_byteCountSinceLastTimerReset * 1000 / m_speedTimer.ElapsedTime();
                m_maxObservedSpeed = STDMAX(m_currentSpeed, m_maxObservedSpeed * 0.98f);
                m_byteCountSinceLastTimerReset = 0;
                m_speedTimer.StartTimer();
//              OutputDebugString(("max speed: " + IntToString((int)m_maxObservedSpeed) + " current speed: " + IntToString((int)m_currentSpeed) + "\n").c_str());
        }
        return m_currentSpeed;
}

float NetworkSink::GetMaxObservedSpeed() const
{
        lword m = GetMaxBytesPerSecond();
        return m ? STDMIN(m_maxObservedSpeed, static_cast<float>(m)) : m_maxObservedSpeed;
}

unsigned int NetworkSink::GetMaxWaitObjectCount() const
{
        return LimitedBandwidth::GetMaxWaitObjectCount() + GetSender().GetMaxWaitObjectCount();
}

void NetworkSink::GetWaitObjects(WaitObjectContainer &container, CallStack const& callStack)
{
        if (BlockedBySpeedLimit())
                LimitedBandwidth::GetWaitObjects(container, CallStack("NetworkSink::GetWaitObjects() - speed limit", &callStack));
        else if (m_wasBlocked)
                AccessSender().GetWaitObjects(container, CallStack("NetworkSink::GetWaitObjects() - was blocked", &callStack));
        else if (!m_buffer.IsEmpty())
                AccessSender().GetWaitObjects(container, CallStack("NetworkSink::GetWaitObjects() - buffer not empty", &callStack));
        else if (EofPending())
                AccessSender().GetWaitObjects(container, CallStack("NetworkSink::GetWaitObjects() - EOF pending", &callStack));
}

size_t NetworkSink::Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
{
        if (m_eofState == EOF_DONE)
        {
                if (length || messageEnd)
                        throw Exception(Exception::OTHER_ERROR, "NetworkSink::Put2() being called after EOF had been sent");

                return 0;
        }

        if (m_eofState > EOF_NONE)
                goto EofSite;

        {
                if (m_skipBytes)
                {
                        CRYPTOPP_ASSERT(length >= m_skipBytes);
                        inString += m_skipBytes;
                        length -= m_skipBytes;
                }

                m_buffer.Put(inString, length);

                if (!blocking || m_buffer.CurrentSize() > m_autoFlushBound)
                        TimedFlush(0, 0);

                size_t targetSize = messageEnd ? 0 : m_maxBufferSize;
                if (blocking)
                        TimedFlush(INFINITE_TIME, targetSize);

                if (m_buffer.CurrentSize() > targetSize)
                {
                        CRYPTOPP_ASSERT(!blocking);
                        m_wasBlocked = true;
                        m_skipBytes += length;
                        size_t blockedBytes = UnsignedMin(length, m_buffer.CurrentSize() - targetSize);
                        return STDMAX<size_t>(blockedBytes, 1);
                }

                m_wasBlocked = false;
                m_skipBytes = 0;
        }

        if (messageEnd)
        {
                m_eofState = EOF_PENDING_SEND;

        EofSite:
                TimedFlush(blocking ? INFINITE_TIME : 0, 0);
                if (m_eofState != EOF_DONE)
                        return 1;
        }

        return 0;
}

lword NetworkSink::DoFlush(unsigned long maxTime, size_t targetSize)
{
        NetworkSender &sender = AccessSender();

        bool forever = maxTime == INFINITE_TIME;
        Timer timer(Timer::MILLISECONDS, forever);
        unsigned int totalFlushSize = 0;

        while (true)
        {
                if (m_buffer.CurrentSize() <= targetSize)
                        break;

                if (m_needSendResult)
                {
                        if (sender.MustWaitForResult() &&
                                !sender.Wait(SaturatingSubtract(maxTime, timer.ElapsedTime()),
                                        CallStack("NetworkSink::DoFlush() - wait send result", 0)))
                                break;

                        unsigned int sendResult = sender.GetSendResult();
#if CRYPTOPP_TRACE_NETWORK
                        OutputDebugString((IntToString((unsigned int)this) + ": Sent " + IntToString(sendResult) + " bytes\n").c_str());
#endif
                        m_buffer.Skip(sendResult);
                        totalFlushSize += sendResult;
                        m_needSendResult = false;

                        if (!m_buffer.AnyRetrievable())
                                break;
                }

                unsigned long timeOut = maxTime ? SaturatingSubtract(maxTime, timer.ElapsedTime()) : 0;
                if (sender.MustWaitToSend() && !sender.Wait(timeOut, CallStack("NetworkSink::DoFlush() - wait send", 0)))
                        break;

                size_t contiguousSize = 0;
                const byte *block = m_buffer.Spy(contiguousSize);

#if CRYPTOPP_TRACE_NETWORK
                OutputDebugString((IntToString((unsigned int)this) + ": Sending " + IntToString(contiguousSize) + " bytes\n").c_str());
#endif
                sender.Send(block, contiguousSize);
                m_needSendResult = true;

                if (maxTime > 0 && timeOut == 0)
                        break;  // once time limit is reached, return even if there is more data waiting
        }

        m_byteCountSinceLastTimerReset += totalFlushSize;
        ComputeCurrentSpeed();

        if (m_buffer.IsEmpty() && !m_needSendResult)
        {
                if (m_eofState == EOF_PENDING_SEND)
                {
                        sender.SendEof();
                        m_eofState = sender.MustWaitForEof() ? EOF_PENDING_DELIVERY : EOF_DONE;
                }

                while (m_eofState == EOF_PENDING_DELIVERY)
                {
                        unsigned long timeOut = maxTime ? SaturatingSubtract(maxTime, timer.ElapsedTime()) : 0;
                        if (!sender.Wait(timeOut, CallStack("NetworkSink::DoFlush() - wait EOF", 0)))
                                break;

                        if (sender.EofSent())
                                m_eofState = EOF_DONE;
                }
        }

        return totalFlushSize;
}

NAMESPACE_END

#endif  // #ifdef SOCKETS_AVAILABLE