tcp.h

diff serve for ns-2, work for version 2.29

/* -*-	Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */ /*
 * Copyright (c) 1991-1997 Regents of the University of California.
 * All rights reserved.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the Computer Systems
 *	Engineering Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 * @(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/tcp/tcp.h,v 1.121 2005/06/20 16:30:30 sfloyd Exp $ (LBL)
 */
#ifndef ns_tcp_h
#define ns_tcp_h

#include "agent.h"
#include "packet.h"

//class EventTrace;

struct hdr_tcp {
#define NSA 3
	double ts_;             /* time packet generated (at source) */
	double ts_echo_;        /* the echoed timestamp (originally sent by
	                           the peer) */
	int seqno_;             /* sequence number */
	int reason_;            /* reason for a retransmit */
	int sack_area_[NSA+1][2];	/* sack blocks: start, end of block */
	int sa_length_;         /* Indicate the number of SACKs in this  *
	                         * packet.  Adds 2+sack_length*8 bytes   */ 
	int ackno_;             /* ACK number for FullTcp */
	int hlen_;              /* header len (bytes) for FullTcp */
	int tcp_flags_;         /* TCP flags for FullTcp */
        int cwnd_;              /* current window - sent for statistic purpose SA*/
        double t_rtt_;          /* current RTT - sent for statistic purpose SA*/
	int last_rtt_;		/* more recent RTT measurement in ms, */
				/*   for statistics only */

	static int offset_;	// offset for this header
	inline static int& offset() { return offset_; }
	inline static hdr_tcp* access(Packet* p) {
		return (hdr_tcp*) p->access(offset_);
	}

	/* per-field member functions */
	double& ts() { return (ts_); }
	double& ts_echo() { return (ts_echo_); }
	int& seqno() { return (seqno_); }
	int& reason() { return (reason_); }
	int& sa_left(int n) { return (sack_area_[n][0]); }
	int& sa_right(int n) { return (sack_area_[n][1]); }
	int& sa_length() { return (sa_length_); }
	int& hlen() { return (hlen_); }
	int& ackno() { return (ackno_); }  
	int& flags() { return (tcp_flags_); }
	int& last_rtt() { return (last_rtt_); }
        int& cwnd() { return (cwnd_); }
        double& t_rtt() { return (t_rtt_); }

};

/* these are used to mark packets as to why we xmitted them */
#define TCP_REASON_TIMEOUT	0x01
#define	TCP_REASON_DUPACK	0x02
#define	TCP_REASON_RBP		0x03   // used only in tcp-rbp.cc
#define TCP_REASON_PARTIALACK   0x04

/* these are reasons we adjusted our congestion window */

#define	CWND_ACTION_DUPACK	1	// dup acks/fast retransmit
#define	CWND_ACTION_TIMEOUT	2	// retransmission timeout
#define	CWND_ACTION_ECN		3	// ECN bit [src quench if supported]
#define CWND_ACTION_EXITED      4       // congestion recovery has ended
					// (when previously CWND_ACTION_DUPACK)

/* these are bits for how to change the cwnd and ssthresh values */

#define	CLOSE_SSTHRESH_HALF	0x00000001
#define	CLOSE_CWND_HALF		0x00000002
#define	CLOSE_CWND_RESTART	0x00000004
#define	CLOSE_CWND_INIT		0x00000008
#define	CLOSE_CWND_ONE		0x00000010
#define CLOSE_SSTHRESH_HALVE	0x00000020
#define CLOSE_CWND_HALVE	0x00000040
#define THREE_QUARTER_SSTHRESH  0x00000080
#define CLOSE_CWND_HALF_WAY 	0x00000100
#define CWND_HALF_WITH_MIN	0x00000200
#define TCP_IDLE		0x00000400
#define NO_OUTSTANDING_DATA     0x00000800

/*
 * tcp_tick_:
 * default 0.1,
 * 0.3 for 4.3 BSD, 
 * 0.01 for new window algorithms,
 */

#define NUMDUPACKS 3		/* This is no longer used.  The variable */
				/* numdupacks_ is used instead. */
#define TCP_MAXSEQ 1073741824   /* Number that curseq_ is set to for */
				/* "infinite send" (2^30)            */

#define TCP_TIMER_RTX		0
#define TCP_TIMER_DELSND	1
#define TCP_TIMER_BURSTSND	2
#define TCP_TIMER_DELACK	3
#define TCP_TIMER_Q         4
#define TCP_TIMER_RESET        5 

class TcpAgent;

class RtxTimer : public TimerHandler {
public: 
	RtxTimer(TcpAgent *a) : TimerHandler() { a_ = a; }
protected:
	virtual void expire(Event *e);
	TcpAgent *a_;
};

class DelSndTimer : public TimerHandler {
public: 
	DelSndTimer(TcpAgent *a) : TimerHandler() { a_ = a; }
protected:
	virtual void expire(Event *e);
	TcpAgent *a_;
};

class BurstSndTimer : public TimerHandler {
public: 
	BurstSndTimer(TcpAgent *a) : TimerHandler() { a_ = a; }
protected:
	virtual void expire(Event *e);
	TcpAgent *a_;
};

/*
 * Variables for HighSpeed TCP.
 */
//int *hs_win_;		// array of cwnd values
//int *hs_increase_;	// array of increase values
//double *hs_decrease_;	// array of decrease values
struct hstcp {
	double low_p;  // low_p
	double dec1;	// for computing the decrease parameter
	double dec2;    // for computing the decrease parameter
	double p1;	// for computing p
        double p2;	// for computing p
	/* The next three parameters are for CPU overhead, for computing */
	/*   the HighSpeed parameters less frequently.  A better solution */
 	/*   might be just to have a look-up array.  */
	double cwnd_last_;	/* last cwnd for computed parameters */
        double increase_last_;	/* increase param for cwnd_last_ */
	hstcp() : low_p(0.0), dec1(0.0), dec2(0.0), p1(0.0), p2(0.0),
	    cwnd_last_(0.0), increase_last_(0.0) { }
};

class TcpAgent : public Agent {
public:
	TcpAgent();
	~TcpAgent() {free(tss);}
        virtual void recv(Packet*, Handler*);
	virtual void timeout(int tno);
	virtual void timeout_nonrtx(int tno);
	int command(int argc, const char*const* argv);
	virtual void sendmsg(int nbytes, const char *flags = 0);

	void trace(TracedVar* v);
	virtual void advanceby(int delta);
protected:
	virtual int window();
	virtual double windowd();
	void print_if_needed(double memb_time);
	void traceAll();
	virtual void traceVar(TracedVar* v);
	virtual int headersize();   // a tcp header

	virtual void delay_bind_init_all();
	virtual int delay_bind_dispatch(const char *varName, const char *localName, TclObject *tracer);

	TracedInt t_seqno_;	/* sequence number */
	/*
	 * State encompassing the round-trip-time estimate.
	 * srtt and rttvar are stored as fixed point;
	 * srtt has 3 bits to the right of the binary point, rttvar has 2.
	 */
	TracedInt t_rtt_;      	/* round trip time */
	TracedInt t_srtt_;     	/* smoothed round-trip time */
	TracedInt t_rttvar_;   	/* variance in round-trip time */
	TracedInt t_backoff_;	/* current multiplier, 1 if not backed off */
	#define T_RTT_BITS 0
	int T_SRTT_BITS;        /* exponent of weight for updating t_srtt_ */
	int srtt_init_;		/* initial value for computing t_srtt_ */
	int T_RTTVAR_BITS;      /* exponent of weight for updating t_rttvar_ */ 
	int rttvar_exp_;        /* exponent of multiple for t_rtxcur_ */
	int rttvar_init_;       /* initial value for computing t_rttvar_ */
	double t_rtxcur_;	/* current retransmit value */
	double rtxcur_init_;    /* initial value for t_rtxcur_ */
	virtual void rtt_init();
	virtual double rtt_timeout();	/* provide RTO based on RTT estimates */
	virtual void rtt_update(double tao);	/* update RTT estimate */
	virtual void rtt_backoff();		/* double multiplier */
	/* End of state for the round-trip-time estimate. */

	/* Timestamps. */
	double ts_peer_;        /* the most recent timestamp the peer sent */
	double ts_echo_;        /* the most recent timestamp the peer echoed */
	int ts_option_size_;    // header bytes in a ts option
        double *tss;            // To store sent timestamps, with bugfix_ts_
        int tss_size_;          // Current capacity of tss
	int ts_option_;		/* use RFC1323-like timestamps? */
	/* End of timestamps. */

	/* connection and packet dynamics */
	virtual void output(int seqno, int reason = 0);
	virtual void send_much(int force, int reason, int maxburst = 0);
	virtual void newtimer(Packet*);
	virtual void dupack_action();		/* do this on dupacks */
	virtual void send_one();		/* do this on 1-2 dupacks */
	double linear(double x, double x_1, double y_1, double x_2, double y_2);
	/* the "linear" function is for experimental highspeed TCP */
	void opencwnd();

	void slowdown(int how);			/* reduce cwnd/ssthresh */
	void ecn(int seqno);		/* react to quench */
	virtual void set_initial_window();	/* set IW */
	double initial_window();		/* what is IW? */
	void reset();
	void newack(Packet*);
	void tcp_eln(Packet *pkt); /* reaction to ELN (usually wireless) */
	void finish(); /* called when the connection is terminated */
	void reset_qoption();	/* for QOption with EnblRTTCtr_ */
	void rtt_counting();	/* for QOption with EnblRTTCtr_ */
	int network_limited();	/* Sending limited by network? */
	double limited_slow_start(double cwnd, double max_ssthresh, double increment);
				/* Limited slow-start for high windows */
	virtual int numdupacks(double cwnd); 	/* for getting numdupacks_ */
	virtual void processQuickStart(Packet *pkt);
	virtual void endQuickStart();
	int lossQuickStart();

	/* Helper functions. Currently used by tcp-asym */
	virtual void output_helper(Packet*) { return; }
	virtual void send_helper(int) { return; }
	virtual void send_idle_helper() { return; }
	virtual void recv_helper(Packet*) { return; }
	virtual void recv_frto_helper(Packet*);
	virtual void recv_newack_helper(Packet*);
	virtual void partialnewack_helper(Packet*) {};
	/* End of helper functions. */

	int force_wnd(int num);
	void spurious_timeout();

	/* Timers */
	RtxTimer rtx_timer_;
	DelSndTimer delsnd_timer_;
	BurstSndTimer burstsnd_timer_;
	virtual void cancel_timers() {
		rtx_timer_.force_cancel();
		burstsnd_timer_.force_cancel();
		delsnd_timer_.force_cancel();
	}
	virtual void cancel_rtx_timer() {
		rtx_timer_.force_cancel();
	}
	virtual void set_rtx_timer();
	void reset_rtx_timer(int mild, int backoff = 1);
	int timerfix_;		/* set to true to update timer *after* */
				/* update the RTT, instead of before   */
	int rfc2988_;		/* Use updated RFC 2988 timers */
	/* End of timers. */ 

	double boot_time_;	/* where between 'ticks' this sytem came up */
	double overhead_;
	double wnd_;
	double wnd_const_;
	double wnd_th_;		/* window "threshold" */
	double wnd_init_;
	double wnd_restart_;
	double tcp_tick_;	/* clock granularity */
	int wnd_option_;
	int wnd_init_option_;   /* 1 for using wnd_init_ */
				/* 2 for using large initial windows */
	double decrease_num_;   /* factor for multiplicative decrease */
	double increase_num_;   /* factor for additive increase */
	int tcpip_base_hdr_size_;  /* size of base TCP/IP header */
	int ts_resetRTO_;	/* Un-backoff RTO after any valid RTT, */
				/*   including from a retransmitted pkt?  */
				/* The old version was "false". */
				/* But "true" gives better performance, and */
                                /* seems conformant with RFC 2988. */
	int maxcwnd_;		/* max # cwnd can ever be */
        int numdupacks_;	/* dup ACKs before fast retransmit */
	int numdupacksFrac_;	/* for a larger numdupacks_ with large */
				/* windows */
	double maxrto_;		/* max value of an RTO */
	double minrto_;         /* min value of an RTO */

	/* For modeling SYN and SYN/ACK packets. */
	int syn_;		/* 1 for modeling SYN/ACK exchange */