/*
* libjingle
* Copyright 2004--2005, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef TALK_P2P_BASE_PSEUDOTCP_H_
#define TALK_P2P_BASE_PSEUDOTCP_H_
#include <list>
#include "talk/base/basictypes.h"
namespace cricket {
//////////////////////////////////////////////////////////////////////
// IPseudoTcpNotify
//////////////////////////////////////////////////////////////////////
class PseudoTcp;
class IPseudoTcpNotify {
public:
virtual ~IPseudoTcpNotify() {}
// 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;
};
//////////////////////////////////////////////////////////////////////
// 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.
enum Option {
OPT_NODELAY, // Whether to enable Nagle's algorithm (0 == off)
OPT_ACKDELAY, // The Delayed ACK timeout (0 == off).
//kOptRcvBuf, // Set the receive buffer size, in bytes.
//kOptSndBuf, // Set the send buffer size, in bytes.
};
void GetOption(Option opt, int* value);
void SetOption(Option opt, int value);
protected:
enum SendFlags { sfNone, sfDelayedAck, sfImmediateAck };
enum {
// Note: can't go as high as 1024 * 64, because of uint16 precision
kRcvBufSize = 1024 * 60,
// Note: send buffer should be larger to make sure we can always fill the
// receiver window
kSndBufSize = 1024 * 90
};
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);
IPseudoTcpNotify::WriteResult packet(uint32 seq, uint8 flags,
const char* data, 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();
private:
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;
char m_rbuf[kRcvBufSize];
uint32 m_rcv_nxt, m_rcv_wnd, m_rlen, m_lastrecv;
// Outgoing data
SList m_slist;
char m_sbuf[kSndBufSize];
uint32 m_snd_nxt, m_snd_wnd, m_slen, m_lastsend, m_snd_una;
// 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;
};
} // namespace cricket
#endif // TALK_P2P_BASE_PSEUDOTCP_H_