tcp_seq.h

T－kernel Tcp/ip Protocol Stack Sample

/****************************************************************************
 * Copyright (C) 2001-2004 MITSUBISHI ELECTRIC CORPORATION and
 * RENESAS SOLUTIONS CORPORATION
 * All rights reserved.
 *
 ****************************************************************************
 * Copyright (c) 1982, 1986, 1993, 1995
 *	The Regents of the University of California.  All rights reserved.
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 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * 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)
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 *
 *	@(#)tcp_seq.h	8.3 (Berkeley) 6/21/95
 *	$Id: tcp_seq.h,v 1.6 1995/10/03 16:54:14 wollman Exp $
 */

#ifndef _NETINET_TCP_SEQ_H_
#define _NETINET_TCP_SEQ_H_
/*
 * TCP sequence numbers are 32 bit integers operated
 * on with modular arithmetic.  These macros can be
 * used to compare such integers.
 */
#define	SEQ_LT(a,b)	((int)((a)-(b)) < 0)
#define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
#define	SEQ_GT(a,b)	((int)((a)-(b)) > 0)
#define	SEQ_GEQ(a,b)	((int)((a)-(b)) >= 0)

/* for modulo comparisons of timestamps */
#define TSTMP_LT(a,b)	((int)((a)-(b)) < 0)
#define TSTMP_GEQ(a,b)	((int)((a)-(b)) >= 0)

/*
 * TCP connection counts are 32 bit integers operated
 * on with modular arithmetic.  These macros can be
 * used to compare such integers.
 */
#define	CC_LT(a,b)	((int)((a)-(b)) < 0)
#define	CC_LEQ(a,b)	((int)((a)-(b)) <= 0)
#define	CC_GT(a,b)	((int)((a)-(b)) > 0)
#define	CC_GEQ(a,b)	((int)((a)-(b)) >= 0)

/* Macro to increment a CC: skip 0 which has a special meaning */
#define CC_INC(c)	(++(c) == 0 ? ++(c) : (c))

/*
 * Macros to initialize tcp sequence numbers for
 * send and receive from initial send and receive
 * sequence numbers.
 */
#define	tcp_rcvseqinit(tp) \
	(tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1

#define	tcp_sendseqinit(tp) \
	(tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
	    (tp)->iss

#define TCP_PAWS_IDLE	(24 * 24 * 60 * 60 * PR_SLOWHZ)
					/* timestamp wrap-around time */

#ifdef KERNEL
extern tcp_cc	tcp_ccgen;		/* global connection count */

/*
 * Increment for tcp_iss each second.
 * This is designed to increment at the standard 250 KB/s,
 * but with a random component averaging 128 KB.
 * We also increment tcp_iss by a quarter of this amount
 * each time we use the value for a new connection.
 * If defined, the tcp_random18() macro should produce a
 * number in the range [0-0x3ffff] that is hard to predict.
 */
#ifndef EMB_SYS
#ifndef tcp_random18
#define	tcp_random18()	((random() >> 14) & 0x3ffff)
#endif
#define	TCP_ISSINCR	(122*1024 + tcp_random18())
#else
#define	TCP_ISSINCR	(250*1024)	/* increment for tcp_iss each second */
#endif /* !EMB_SYS */

extern tcp_seq	tcp_iss;		/* tcp initial send seq # */
#else
#define	TCP_ISSINCR	(250*1024)	/* increment for tcp_iss each second */
#endif /* KERNEL */
#endif /* _NETINET_TCP_SEQ_H_ */