xref: /freebsd/sys/netinet/tcp_seq.h (revision b1f9167f94059fd55c630891d359bcff987bd7eb)
1 /*-
2  * Copyright (c) 1982, 1986, 1993, 1995
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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	@(#)tcp_seq.h	8.3 (Berkeley) 6/21/95
30  * $FreeBSD$
31  */
32 
33 #ifndef _NETINET_TCP_SEQ_H_
34 #define _NETINET_TCP_SEQ_H_
35 /*
36  * TCP sequence numbers are 32 bit integers operated
37  * on with modular arithmetic.  These macros can be
38  * used to compare such integers.
39  */
40 #define	SEQ_LT(a,b)	((int)((a)-(b)) < 0)
41 #define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
42 #define	SEQ_GT(a,b)	((int)((a)-(b)) > 0)
43 #define	SEQ_GEQ(a,b)	((int)((a)-(b)) >= 0)
44 
45 #define	SEQ_MIN(a, b)	((SEQ_LT(a, b)) ? (a) : (b))
46 #define	SEQ_MAX(a, b)	((SEQ_GT(a, b)) ? (a) : (b))
47 
48 /* for modulo comparisons of timestamps */
49 #define TSTMP_LT(a,b)	((int)((a)-(b)) < 0)
50 #define TSTMP_GT(a,b)	((int)((a)-(b)) > 0)
51 #define TSTMP_GEQ(a,b)	((int)((a)-(b)) >= 0)
52 
53 /*
54  * Macros to initialize tcp sequence numbers for
55  * send and receive from initial send and receive
56  * sequence numbers.
57  */
58 #define	tcp_rcvseqinit(tp) \
59 	(tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
60 
61 #define	tcp_sendseqinit(tp) \
62 	(tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
63 	    (tp)->snd_recover = (tp)->iss
64 
65 #ifdef _KERNEL
66 /*
67  * Clock macros for RFC 1323 timestamps.
68  */
69 #define	TCP_TS_TO_TICKS(_t)	((_t) * hz / 1000)
70 
71 /* Timestamp wrap-around time, 24 days. */
72 #define TCP_PAWS_IDLE	(24 * 24 * 60 * 60 * 1000)
73 
74 /*
75  * tcp_ts_getticks() in ms, should be 1ms < x < 1000ms according to RFC 1323.
76  * We always use 1ms granularity independent of hz.
77  */
78 static __inline u_int
79 tcp_ts_getticks(void)
80 {
81 	struct timeval tv;
82 	u_long ms;
83 
84 	/*
85 	 * getmicrouptime() should be good enough for any 1-1000ms granularity.
86 	 * Do not use getmicrotime() here as it might break nfsroot/tcp.
87 	 */
88 	getmicrouptime(&tv);
89 	ms = tv.tv_sec * 1000 + tv.tv_usec / 1000;
90 
91 	return (ms);
92 }
93 #endif /* _KERNEL */
94 
95 #endif /* _NETINET_TCP_SEQ_H_ */
96