xref: /original-bsd/sys/netinet/tcp_seq.h (revision 279692fa)
1 /*
2  * Copyright (c) 1982, 1986 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  *
17  *	@(#)tcp_seq.h	7.3 (Berkeley) 06/29/88
18  */
19 
20 /*
21  * TCP sequence numbers are 32 bit integers operated
22  * on with modular arithmetic.  These macros can be
23  * used to compare such integers.
24  */
25 #define	SEQ_LT(a,b)	((int)((a)-(b)) < 0)
26 #define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
27 #define	SEQ_GT(a,b)	((int)((a)-(b)) > 0)
28 #define	SEQ_GEQ(a,b)	((int)((a)-(b)) >= 0)
29 
30 /*
31  * Macros to initialize tcp sequence numbers for
32  * send and receive from initial send and receive
33  * sequence numbers.
34  */
35 #define	tcp_rcvseqinit(tp) \
36 	(tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
37 
38 #define	tcp_sendseqinit(tp) \
39 	(tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
40 	    (tp)->iss
41 
42 #define	TCP_ISSINCR	(125*1024)	/* increment for tcp_iss each second */
43 
44 #ifdef KERNEL
45 tcp_seq	tcp_iss;		/* tcp initial send seq # */
46 #endif
47