xref: /src/sys/netinet/tcp_seq.h

/*	$NetBSD: tcp_seq.h,v 1.8 1997/10/13 00:48:10 explorer Exp $	*/

/*
 * Copyright (c) 1982, 1986, 1993
 *	The 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 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.
 *
 * 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.
 *
 *	@(#)tcp_seq.h	8.1 (Berkeley) 6/10/93
 */

/*
 * 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)

/*
 * 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_ISS_RANDOM_MASK 0x0003ffff /* bits of randomness in a TCP ISS */
#define TCP_ISSINCR         0x00040000 /* increment per time and per conn */

#ifdef _KERNEL
extern tcp_seq	 tcp_iss_seq;		/* tcp initial seq # */
#endif