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/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef WEBRTC_P2P_BASE_PSEUDOTCP_H_
#define WEBRTC_P2P_BASE_PSEUDOTCP_H_
#include <list>
#include "webrtc/base/basictypes.h"
#include "webrtc/base/stream.h"
namespace cricket {
//////////////////////////////////////////////////////////////////////
// IPseudoTcpNotify
//////////////////////////////////////////////////////////////////////
class PseudoTcp;
class IPseudoTcpNotify {
public:
// Notification of tcp events
virtual void OnTcpOpen(PseudoTcp* tcp) = 0;
virtual void OnTcpReadable(PseudoTcp* tcp) = 0;
virtual void OnTcpWriteable(PseudoTcp* tcp) = 0;
virtual void OnTcpClosed(PseudoTcp* tcp, uint32 error) = 0;
// Write the packet onto the network
enum WriteResult { WR_SUCCESS, WR_TOO_LARGE, WR_FAIL };
virtual WriteResult TcpWritePacket(PseudoTcp* tcp,
const char* buffer, size_t len) = 0;
protected:
virtual ~IPseudoTcpNotify() {}
};
//////////////////////////////////////////////////////////////////////
// PseudoTcp
//////////////////////////////////////////////////////////////////////
class PseudoTcp {
public:
static uint32 Now();
PseudoTcp(IPseudoTcpNotify* notify, uint32 conv);
virtual ~PseudoTcp();
int Connect();
int Recv(char* buffer, size_t len);
int Send(const char* buffer, size_t len);
void Close(bool force);
int GetError();
enum TcpState {
TCP_LISTEN, TCP_SYN_SENT, TCP_SYN_RECEIVED, TCP_ESTABLISHED, TCP_CLOSED
};
TcpState State() const { return m_state; }
// Call this when the PMTU changes.
void NotifyMTU(uint16 mtu);
// Call this based on timeout value returned from GetNextClock.
// It's ok to call this too frequently.
void NotifyClock(uint32 now);
// Call this whenever a packet arrives.
// Returns true if the packet was processed successfully.
bool NotifyPacket(const char * buffer, size_t len);
// Call this to determine the next time NotifyClock should be called.
// Returns false if the socket is ready to be destroyed.
bool GetNextClock(uint32 now, long& timeout);
// Call these to get/set option values to tailor this PseudoTcp
// instance's behaviour for the kind of data it will carry.
// If an unrecognized option is set or got, an assertion will fire.
//
// Setting options for OPT_RCVBUF or OPT_SNDBUF after Connect() is called
// will result in an assertion.
enum Option {
OPT_NODELAY, // Whether to enable Nagle's algorithm (0 == off)
OPT_ACKDELAY, // The Delayed ACK timeout (0 == off).
OPT_RCVBUF, // Set the receive buffer size, in bytes.
OPT_SNDBUF, // Set the send buffer size, in bytes.
};
void GetOption(Option opt, int* value);
void SetOption(Option opt, int value);
// Returns current congestion window in bytes.
uint32 GetCongestionWindow() const;
// Returns amount of data in bytes that has been sent, but haven't
// been acknowledged.
uint32 GetBytesInFlight() const;
// Returns number of bytes that were written in buffer and haven't
// been sent.
uint32 GetBytesBufferedNotSent() const;
// Returns current round-trip time estimate in milliseconds.
uint32 GetRoundTripTimeEstimateMs() const;
protected:
enum SendFlags { sfNone, sfDelayedAck, sfImmediateAck };
struct Segment {
uint32 conv, seq, ack;
uint8 flags;
uint16 wnd;
const char * data;
uint32 len;
uint32 tsval, tsecr;
};
struct SSegment {
SSegment(uint32 s, uint32 l, bool c)
: seq(s), len(l), /*tstamp(0),*/ xmit(0), bCtrl(c) {
}
uint32 seq, len;
//uint32 tstamp;
uint8 xmit;
bool bCtrl;
};
typedef std::list<SSegment> SList;
struct RSegment {
uint32 seq, len;
};
uint32 queue(const char* data, uint32 len, bool bCtrl);
// Creates a packet and submits it to the network. This method can either
// send payload or just an ACK packet.
//
// |seq| is the sequence number of this packet.
// |flags| is the flags for sending this packet.
// |offset| is the offset to read from |m_sbuf|.
// |len| is the number of bytes to read from |m_sbuf| as payload. If this
// value is 0 then this is an ACK packet, otherwise this packet has payload.
IPseudoTcpNotify::WriteResult packet(uint32 seq, uint8 flags,
uint32 offset, uint32 len);
bool parse(const uint8* buffer, uint32 size);
void attemptSend(SendFlags sflags = sfNone);
void closedown(uint32 err = 0);
bool clock_check(uint32 now, long& nTimeout);
bool process(Segment& seg);
bool transmit(const SList::iterator& seg, uint32 now);
void adjustMTU();
protected:
// This method is used in test only to query receive buffer state.
bool isReceiveBufferFull() const;
// This method is only used in tests, to disable window scaling
// support for testing backward compatibility.
void disableWindowScale();
private:
// Queue the connect message with TCP options.
void queueConnectMessage();
// Parse TCP options in the header.
void parseOptions(const char* data, uint32 len);
// Apply a TCP option that has been read from the header.
void applyOption(char kind, const char* data, uint32 len);
// Apply window scale option.
void applyWindowScaleOption(uint8 scale_factor);
// Resize the send buffer with |new_size| in bytes.
void resizeSendBuffer(uint32 new_size);
// Resize the receive buffer with |new_size| in bytes. This call adjusts
// window scale factor |m_swnd_scale| accordingly.
void resizeReceiveBuffer(uint32 new_size);
IPseudoTcpNotify* m_notify;
enum Shutdown { SD_NONE, SD_GRACEFUL, SD_FORCEFUL } m_shutdown;
int m_error;
// TCB data
TcpState m_state;
uint32 m_conv;
bool m_bReadEnable, m_bWriteEnable, m_bOutgoing;
uint32 m_lasttraffic;
// Incoming data
typedef std::list<RSegment> RList;
RList m_rlist;
uint32 m_rbuf_len, m_rcv_nxt, m_rcv_wnd, m_lastrecv;
uint8 m_rwnd_scale; // Window scale factor.
rtc::FifoBuffer m_rbuf;
// Outgoing data
SList m_slist;
uint32 m_sbuf_len, m_snd_nxt, m_snd_wnd, m_lastsend, m_snd_una;
uint8 m_swnd_scale; // Window scale factor.
rtc::FifoBuffer m_sbuf;
// Maximum segment size, estimated protocol level, largest segment sent
uint32 m_mss, m_msslevel, m_largest, m_mtu_advise;
// Retransmit timer
uint32 m_rto_base;
// Timestamp tracking
uint32 m_ts_recent, m_ts_lastack;
// Round-trip calculation
uint32 m_rx_rttvar, m_rx_srtt, m_rx_rto;
// Congestion avoidance, Fast retransmit/recovery, Delayed ACKs
uint32 m_ssthresh, m_cwnd;
uint8 m_dup_acks;
uint32 m_recover;
uint32 m_t_ack;
// Configuration options
bool m_use_nagling;
uint32 m_ack_delay;
// This is used by unit tests to test backward compatibility of
// PseudoTcp implementations that don't support window scaling.
bool m_support_wnd_scale;
};
} // namespace cricket
#endif // WEBRTC_P2P_BASE_PSEUDOTCP_H_