xref: /freebsd/sys/netinet/tcp_seq.h (revision b7a1a0a5ff8895e6a5c9404d02357ac9e2eb8091)
1 /*
2  * Copyright (c) 1982, 1986, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)tcp_seq.h	8.1 (Berkeley) 6/10/93
34  * $Id: tcp_seq.h,v 1.2 1994/08/02 07:49:06 davidg Exp $
35  */
36 
37 #ifndef _NETINET_TCP_SEQ_H_
38 #define _NETINET_TCP_SEQ_H_
39 /*
40  * TCP sequence numbers are 32 bit integers operated
41  * on with modular arithmetic.  These macros can be
42  * used to compare such integers.
43  */
44 #define	SEQ_LT(a,b)	((int)((a)-(b)) < 0)
45 #define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
46 #define	SEQ_GT(a,b)	((int)((a)-(b)) > 0)
47 #define	SEQ_GEQ(a,b)	((int)((a)-(b)) >= 0)
48 
49 /*
50  * Macros to initialize tcp sequence numbers for
51  * send and receive from initial send and receive
52  * sequence numbers.
53  */
54 #define	tcp_rcvseqinit(tp) \
55 	(tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
56 
57 #define	tcp_sendseqinit(tp) \
58 	(tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
59 	    (tp)->iss
60 
61 #define	TCP_ISSINCR	(125*1024)	/* increment for tcp_iss each second */
62 
63 #ifdef KERNEL
64 tcp_seq	tcp_iss;		/* tcp initial send seq # */
65 #endif
66 #endif
67