cryptopp/network.h

#ifndef CRYPTOPP_NETWORK_H
#define CRYPTOPP_NETWORK_H

#include "config.h"

#ifdef HIGHRES_TIMER_AVAILABLE

#include "filters.h"
#include "hrtimer.h"

#include <deque>

NAMESPACE_BEGIN(CryptoPP)

class LimitedBandwidth
{
public:
	LimitedBandwidth(lword maxBytesPerSecond = 0)
		: m_maxBytesPerSecond(maxBytesPerSecond), m_timer(Timer::MILLISECONDS)
		, m_nextTransceiveTime(0)
		{ m_timer.StartTimer(); }

	lword GetMaxBytesPerSecond() const
		{ return m_maxBytesPerSecond; }

	void SetMaxBytesPerSecond(lword v)
		{ m_maxBytesPerSecond = v; }

	lword ComputeCurrentTransceiveLimit();

	double TimeToNextTransceive();

	void NoteTransceive(lword size);

public:
	/*! GetWaitObjects() must be called despite the 0 return from GetMaxWaitObjectCount();
	    the 0 is because the ScheduleEvent() method is used instead of adding a wait object */
	unsigned int GetMaxWaitObjectCount() const { return 0; }
	void GetWaitObjects(WaitObjectContainer &container, const CallStack &callStack);

private:	
	lword m_maxBytesPerSecond;

	typedef std::deque<std::pair<double, lword> > OpQueue;
	OpQueue m_ops;

	Timer m_timer;
	double m_nextTransceiveTime;

	void ComputeNextTransceiveTime();
	double GetCurTimeAndCleanUp();
};

//! a Source class that can pump from a device for a specified amount of time.
class CRYPTOPP_NO_VTABLE NonblockingSource : public AutoSignaling<Source>, public LimitedBandwidth
{
public:
	NonblockingSource(BufferedTransformation *attachment)
		: m_messageEndSent(false) , m_doPumpBlocked(false), m_blockedBySpeedLimit(false) {Detach(attachment);}

	//!	\name NONBLOCKING SOURCE
	//@{

	//! pump up to maxSize bytes using at most maxTime milliseconds
	/*! If checkDelimiter is true, pump up to delimiter, which itself is not extracted or pumped. */
	size_t GeneralPump2(lword &byteCount, bool blockingOutput=true, unsigned long maxTime=INFINITE_TIME, bool checkDelimiter=false, byte delimiter='\n');

	lword GeneralPump(lword maxSize=LWORD_MAX, unsigned long maxTime=INFINITE_TIME, bool checkDelimiter=false, byte delimiter='\n')
	{
		GeneralPump2(maxSize, true, maxTime, checkDelimiter, delimiter);
		return maxSize;
	}
	lword TimedPump(unsigned long maxTime)
		{return GeneralPump(LWORD_MAX, maxTime);}
	lword PumpLine(byte delimiter='\n', lword maxSize=1024)
		{return GeneralPump(maxSize, INFINITE_TIME, true, delimiter);}

	size_t Pump2(lword &byteCount, bool blocking=true)
		{return GeneralPump2(byteCount, blocking, blocking ? INFINITE_TIME : 0);}
	size_t PumpMessages2(unsigned int &messageCount, bool blocking=true);
	//@}

protected:
	virtual size_t DoPump(lword &byteCount, bool blockingOutput,
		unsigned long maxTime, bool checkDelimiter, byte delimiter) =0;

	bool BlockedBySpeedLimit() const { return m_blockedBySpeedLimit; }

private:
	bool m_messageEndSent, m_doPumpBlocked, m_blockedBySpeedLimit;
};

//! Network Receiver
class CRYPTOPP_NO_VTABLE NetworkReceiver : public Waitable
{
public:
	virtual bool MustWaitToReceive() {return false;}
	virtual bool MustWaitForResult() {return false;}
	//! receive data from network source, returns whether result is immediately available
	virtual bool Receive(byte* buf, size_t bufLen) =0;
	virtual unsigned int GetReceiveResult() =0;
	virtual bool EofReceived() const =0;
};

class CRYPTOPP_NO_VTABLE NonblockingSinkInfo
{
public:
	virtual ~NonblockingSinkInfo() {}
	virtual size_t GetMaxBufferSize() const =0;
	virtual size_t GetCurrentBufferSize() const =0;
	virtual bool EofPending() const =0;
	//! compute the current speed of this sink in bytes per second
	virtual float ComputeCurrentSpeed() =0;
	//! get the maximum observed speed of this sink in bytes per second
	virtual float GetMaxObservedSpeed() const =0;
};

//! a Sink class that queues input and can std::flush to a device for a specified amount of time.
class CRYPTOPP_NO_VTABLE NonblockingSink : public Sink, public NonblockingSinkInfo, public LimitedBandwidth
{
public:
	NonblockingSink() : m_blockedBySpeedLimit(false) {}

	bool IsolatedFlush(bool hardFlush, bool blocking);

	//! std::flush to device for no more than maxTime milliseconds
	/*! This function will repeatedly attempt to std::flush data to some device, until
		the queue is empty, or a total of maxTime milliseconds have elapsed.
		If maxTime == 0, at least one attempt will be made to std::flush some data, but
		it is likely that not all queued data will be std::flushed, even if the device
		is ready to receive more data without waiting. If you want to std::flush as much data
		as possible without waiting for the device, call this function in a loop.
		For example: while (sink.TimedFlush(0) > 0) {}
		\return number of bytes std::flushed
	*/
	lword TimedFlush(unsigned long maxTime, size_t targetSize = 0);

	virtual void SetMaxBufferSize(size_t maxBufferSize) =0;
	//! set a bound which will cause sink to std::flush if exceeded by GetCurrentBufferSize()
	virtual void SetAutoFlushBound(size_t bound) =0;

protected:
	virtual lword DoFlush(unsigned long maxTime, size_t targetSize) = 0;

	bool BlockedBySpeedLimit() const { return m_blockedBySpeedLimit; }

private:
	bool m_blockedBySpeedLimit;
};

//! Network Sender
class CRYPTOPP_NO_VTABLE NetworkSender : public Waitable
{
public:
	virtual bool MustWaitToSend() {return false;}
	virtual bool MustWaitForResult() {return false;}
	virtual void Send(const byte* buf, size_t bufLen) =0;
	virtual unsigned int GetSendResult() =0;
	virtual bool MustWaitForEof() {return false;}
	virtual void SendEof() =0;
	virtual bool EofSent() {return false;}	// implement if MustWaitForEof() == true
};

//! Network Source
class CRYPTOPP_NO_VTABLE NetworkSource : public NonblockingSource
{
public:
	NetworkSource(BufferedTransformation *attachment);

	unsigned int GetMaxWaitObjectCount() const;
	void GetWaitObjects(WaitObjectContainer &container, CallStack const& callStack);

	bool SourceExhausted() const {return m_dataBegin == m_dataEnd && GetReceiver().EofReceived();}

protected:
	size_t DoPump(lword &byteCount, bool blockingOutput, unsigned long maxTime, bool checkDelimiter, byte delimiter);

	virtual NetworkReceiver & AccessReceiver() =0;
	const NetworkReceiver & GetReceiver() const {return const_cast<NetworkSource *>(this)->AccessReceiver();}

private:
	SecByteBlock m_buf;
	size_t m_putSize, m_dataBegin, m_dataEnd;
	bool m_waitingForResult, m_outputBlocked;
};

//! Network Sink
class CRYPTOPP_NO_VTABLE NetworkSink : public NonblockingSink
{
public:
	NetworkSink(unsigned int maxBufferSize, unsigned int autoFlushBound);

	unsigned int GetMaxWaitObjectCount() const;
	void GetWaitObjects(WaitObjectContainer &container, CallStack const& callStack);

	size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);

	void SetMaxBufferSize(size_t maxBufferSize) {m_maxBufferSize = maxBufferSize; m_buffer.SetNodeSize(UnsignedMin(maxBufferSize, 16U*1024U+256U));}
	void SetAutoFlushBound(size_t bound) {m_autoFlushBound = bound;}

	size_t GetMaxBufferSize() const {return m_maxBufferSize;}
	size_t GetCurrentBufferSize() const {return (size_t)m_buffer.CurrentSize();}

	void ClearBuffer() { m_buffer.Clear(); }

	bool EofPending() const { return m_eofState > EOF_NONE && m_eofState < EOF_DONE; }

	//! compute the current speed of this sink in bytes per second
	float ComputeCurrentSpeed();
	//! get the maximum observed speed of this sink in bytes per second
	float GetMaxObservedSpeed() const;

protected:
	lword DoFlush(unsigned long maxTime, size_t targetSize);

	virtual NetworkSender & AccessSender() =0;
	const NetworkSender & GetSender() const {return const_cast<NetworkSink *>(this)->AccessSender();}

private:
	enum EofState { EOF_NONE, EOF_PENDING_SEND, EOF_PENDING_DELIVERY, EOF_DONE };

	size_t m_maxBufferSize, m_autoFlushBound;
	bool m_needSendResult, m_wasBlocked;
	EofState m_eofState;
	ByteQueue m_buffer;
	size_t m_skipBytes;
	Timer m_speedTimer;
	float m_byteCountSinceLastTimerReset, m_currentSpeed, m_maxObservedSpeed;
};

NAMESPACE_END

#endif	// #ifdef HIGHRES_TIMER_AVAILABLE

#endif