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98 lines
2.6 KiB
C++
98 lines
2.6 KiB
C++
/* Copyright 2009-2018 Pierre Ossman for Cendio AB
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*
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* This is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This software is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this software; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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* USA.
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*/
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#ifndef __RFB_CONGESTION_H__
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#define __RFB_CONGESTION_H__
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#include <list>
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namespace rfb {
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class Congestion {
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public:
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Congestion();
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~Congestion();
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// updatePosition() registers the current stream position and can
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// and should be called often.
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void updatePosition(unsigned pos);
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// sentPing() must be called when a marker is placed on the
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// outgoing stream. gotPong() must be called when the response for
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// such a marker is received.
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void sentPing();
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void gotPong();
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// isCongested() determines if the transport is currently congested
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// or if more data can be sent.
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bool isCongested();
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// getUncongestedETA() returns the number of milliseconds until the
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// transport is no longer congested. Returns 0 if there is no
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// congestion, and -1 if it is unknown when the transport will no
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// longer be congested.
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int getUncongestedETA();
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// getBandwidth() returns the current bandwidth estimation in bytes
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// per second.
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size_t getBandwidth();
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unsigned getPingTime() const;
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// debugTrace() writes the current congestion window, as well as the
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// congestion window of the underlying TCP layer, to the specified
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// file
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void debugTrace(const char* filename, int fd);
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protected:
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unsigned getExtraBuffer();
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unsigned getInFlight();
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void updateCongestion();
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private:
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unsigned lastPosition;
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unsigned extraBuffer;
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struct timeval lastUpdate;
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struct timeval lastSent;
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unsigned baseRTT;
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unsigned congWindow;
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bool inSlowStart;
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unsigned safeBaseRTT;
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struct RTTInfo {
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struct timeval tv;
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unsigned pos;
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unsigned extra;
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bool congested;
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};
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std::list<struct RTTInfo> pings;
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struct RTTInfo lastPong;
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struct timeval lastPongArrival;
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int measurements;
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struct timeval lastAdjustment;
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unsigned minRTT, minCongestedRTT;
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};
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}
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#endif
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