28e2075280
trunk/talk git-svn-id: http://webrtc.googlecode.com/svn/trunk@4318 4adac7df-926f-26a2-2b94-8c16560cd09d
259 lines
8.2 KiB
C++
259 lines
8.2 KiB
C++
/*
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* libjingle
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* Copyright 2004--2005, Google Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
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* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TALK_P2P_BASE_PSEUDOTCP_H_
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#define TALK_P2P_BASE_PSEUDOTCP_H_
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#include <list>
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#include "talk/base/basictypes.h"
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#include "talk/base/stream.h"
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namespace cricket {
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//////////////////////////////////////////////////////////////////////
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// IPseudoTcpNotify
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//////////////////////////////////////////////////////////////////////
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class PseudoTcp;
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class IPseudoTcpNotify {
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public:
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// Notification of tcp events
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virtual void OnTcpOpen(PseudoTcp* tcp) = 0;
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virtual void OnTcpReadable(PseudoTcp* tcp) = 0;
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virtual void OnTcpWriteable(PseudoTcp* tcp) = 0;
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virtual void OnTcpClosed(PseudoTcp* tcp, uint32 error) = 0;
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// Write the packet onto the network
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enum WriteResult { WR_SUCCESS, WR_TOO_LARGE, WR_FAIL };
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virtual WriteResult TcpWritePacket(PseudoTcp* tcp,
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const char* buffer, size_t len) = 0;
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protected:
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virtual ~IPseudoTcpNotify() {}
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};
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//////////////////////////////////////////////////////////////////////
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// PseudoTcp
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//////////////////////////////////////////////////////////////////////
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class PseudoTcp {
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public:
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static uint32 Now();
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PseudoTcp(IPseudoTcpNotify* notify, uint32 conv);
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virtual ~PseudoTcp();
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int Connect();
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int Recv(char* buffer, size_t len);
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int Send(const char* buffer, size_t len);
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void Close(bool force);
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int GetError();
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enum TcpState {
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TCP_LISTEN, TCP_SYN_SENT, TCP_SYN_RECEIVED, TCP_ESTABLISHED, TCP_CLOSED
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};
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TcpState State() const { return m_state; }
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// Call this when the PMTU changes.
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void NotifyMTU(uint16 mtu);
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// Call this based on timeout value returned from GetNextClock.
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// It's ok to call this too frequently.
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void NotifyClock(uint32 now);
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// Call this whenever a packet arrives.
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// Returns true if the packet was processed successfully.
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bool NotifyPacket(const char * buffer, size_t len);
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// Call this to determine the next time NotifyClock should be called.
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// Returns false if the socket is ready to be destroyed.
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bool GetNextClock(uint32 now, long& timeout);
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// Call these to get/set option values to tailor this PseudoTcp
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// instance's behaviour for the kind of data it will carry.
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// If an unrecognized option is set or got, an assertion will fire.
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//
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// Setting options for OPT_RCVBUF or OPT_SNDBUF after Connect() is called
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// will result in an assertion.
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enum Option {
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OPT_NODELAY, // Whether to enable Nagle's algorithm (0 == off)
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OPT_ACKDELAY, // The Delayed ACK timeout (0 == off).
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OPT_RCVBUF, // Set the receive buffer size, in bytes.
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OPT_SNDBUF, // Set the send buffer size, in bytes.
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};
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void GetOption(Option opt, int* value);
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void SetOption(Option opt, int value);
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// Returns current congestion window in bytes.
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uint32 GetCongestionWindow() const;
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// Returns amount of data in bytes that has been sent, but haven't
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// been acknowledged.
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uint32 GetBytesInFlight() const;
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// Returns number of bytes that were written in buffer and haven't
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// been sent.
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uint32 GetBytesBufferedNotSent() const;
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// Returns current round-trip time estimate in milliseconds.
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uint32 GetRoundTripTimeEstimateMs() const;
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protected:
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enum SendFlags { sfNone, sfDelayedAck, sfImmediateAck };
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struct Segment {
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uint32 conv, seq, ack;
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uint8 flags;
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uint16 wnd;
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const char * data;
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uint32 len;
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uint32 tsval, tsecr;
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};
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struct SSegment {
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SSegment(uint32 s, uint32 l, bool c)
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: seq(s), len(l), /*tstamp(0),*/ xmit(0), bCtrl(c) {
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}
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uint32 seq, len;
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//uint32 tstamp;
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uint8 xmit;
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bool bCtrl;
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};
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typedef std::list<SSegment> SList;
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struct RSegment {
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uint32 seq, len;
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};
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uint32 queue(const char* data, uint32 len, bool bCtrl);
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// Creates a packet and submits it to the network. This method can either
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// send payload or just an ACK packet.
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//
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// |seq| is the sequence number of this packet.
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// |flags| is the flags for sending this packet.
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// |offset| is the offset to read from |m_sbuf|.
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// |len| is the number of bytes to read from |m_sbuf| as payload. If this
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// value is 0 then this is an ACK packet, otherwise this packet has payload.
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IPseudoTcpNotify::WriteResult packet(uint32 seq, uint8 flags,
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uint32 offset, uint32 len);
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bool parse(const uint8* buffer, uint32 size);
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void attemptSend(SendFlags sflags = sfNone);
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void closedown(uint32 err = 0);
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bool clock_check(uint32 now, long& nTimeout);
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bool process(Segment& seg);
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bool transmit(const SList::iterator& seg, uint32 now);
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void adjustMTU();
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protected:
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// This method is used in test only to query receive buffer state.
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bool isReceiveBufferFull() const;
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// This method is only used in tests, to disable window scaling
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// support for testing backward compatibility.
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void disableWindowScale();
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private:
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// Queue the connect message with TCP options.
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void queueConnectMessage();
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// Parse TCP options in the header.
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void parseOptions(const char* data, uint32 len);
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// Apply a TCP option that has been read from the header.
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void applyOption(char kind, const char* data, uint32 len);
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// Apply window scale option.
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void applyWindowScaleOption(uint8 scale_factor);
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// Resize the send buffer with |new_size| in bytes.
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void resizeSendBuffer(uint32 new_size);
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// Resize the receive buffer with |new_size| in bytes. This call adjusts
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// window scale factor |m_swnd_scale| accordingly.
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void resizeReceiveBuffer(uint32 new_size);
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IPseudoTcpNotify* m_notify;
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enum Shutdown { SD_NONE, SD_GRACEFUL, SD_FORCEFUL } m_shutdown;
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int m_error;
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// TCB data
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TcpState m_state;
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uint32 m_conv;
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bool m_bReadEnable, m_bWriteEnable, m_bOutgoing;
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uint32 m_lasttraffic;
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// Incoming data
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typedef std::list<RSegment> RList;
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RList m_rlist;
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uint32 m_rbuf_len, m_rcv_nxt, m_rcv_wnd, m_lastrecv;
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uint8 m_rwnd_scale; // Window scale factor.
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talk_base::FifoBuffer m_rbuf;
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// Outgoing data
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SList m_slist;
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uint32 m_sbuf_len, m_snd_nxt, m_snd_wnd, m_lastsend, m_snd_una;
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uint8 m_swnd_scale; // Window scale factor.
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talk_base::FifoBuffer m_sbuf;
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// Maximum segment size, estimated protocol level, largest segment sent
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uint32 m_mss, m_msslevel, m_largest, m_mtu_advise;
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// Retransmit timer
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uint32 m_rto_base;
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// Timestamp tracking
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uint32 m_ts_recent, m_ts_lastack;
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// Round-trip calculation
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uint32 m_rx_rttvar, m_rx_srtt, m_rx_rto;
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// Congestion avoidance, Fast retransmit/recovery, Delayed ACKs
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uint32 m_ssthresh, m_cwnd;
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uint8 m_dup_acks;
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uint32 m_recover;
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uint32 m_t_ack;
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// Configuration options
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bool m_use_nagling;
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uint32 m_ack_delay;
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// This is used by unit tests to test backward compatibility of
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// PseudoTcp implementations that don't support window scaling.
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bool m_support_wnd_scale;
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};
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} // namespace cricket
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#endif // TALK_P2P_BASE_PSEUDOTCP_H_
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