xref: /freebsd/sys/netinet/tcp_seq.h (revision 2e3f49888ec8851bafb22011533217487764fdb0)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1993, 1995
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #ifndef _NETINET_TCP_SEQ_H_
33 #define _NETINET_TCP_SEQ_H_
34 /*
35  * TCP sequence numbers are 32 bit integers operated
36  * on with modular arithmetic.  These macros can be
37  * used to compare such integers.
38  */
39 #define	SEQ_LT(a,b)	((int)((a)-(b)) < 0)
40 #define	SEQ_LEQ(a,b)	((int)((a)-(b)) <= 0)
41 #define	SEQ_GT(a,b)	((int)((a)-(b)) > 0)
42 #define	SEQ_GEQ(a,b)	((int)((a)-(b)) >= 0)
43 #define	SEQ_SUB(a,b)	((int)((a)-(b)))
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 #define	WIN_LT(a,b)	(ntohs(a) < ntohs(b))
49 #define	WIN_LEQ(a,b)	(ntohs(a) <= ntohs(b))
50 #define	WIN_GT(a,b)	(ntohs(a) > ntohs(b))
51 #define	WIN_GEQ(a,b)	(ntohs(a) >= ntohs(b))
52 
53 #define	WIN_MIN(a, b)	((WIN_LT(a, b)) ? (a) : (b))
54 #define	WIN_MAX(a, b)	((WIN_GT(a, b)) ? (a) : (b))
55 
56 /* for modulo comparisons of timestamps */
57 #define TSTMP_LT(a,b)	((int)((a)-(b)) < 0)
58 #define TSTMP_GT(a,b)	((int)((a)-(b)) > 0)
59 #define TSTMP_GEQ(a,b)	((int)((a)-(b)) >= 0)
60 
61 /*
62  * Macros to initialize tcp sequence numbers for
63  * send and receive from initial send and receive
64  * sequence numbers.
65  */
66 #define	tcp_rcvseqinit(tp) \
67 	(tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
68 
69 #define	tcp_sendseqinit(tp) \
70 	(tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
71 	    (tp)->snd_recover = (tp)->iss
72 
73 #ifdef _KERNEL
74 /*
75  * Clock macros for RFC 1323 timestamps.
76  */
77 #define	TCP_TS_TO_TICKS(_t)	((_t) * hz / 1000)
78 
79 /* Timestamp wrap-around time, 24 days. */
80 #define TCP_PAWS_IDLE	(24 * 24 * 60 * 60 * 1000)
81 
82 /*
83  * tcp_ts_getticks() in ms, should be 1ms < x < 1000ms according to RFC 1323.
84  * We always use 1ms granularity independent of hz.
85  */
86 static __inline uint32_t
87 tcp_ts_getticks(void)
88 {
89 	struct timeval tv;
90 
91 	/*
92 	 * getmicrouptime() should be good enough for any 1-1000ms granularity.
93 	 * Do not use getmicrotime() here as it might break nfsroot/tcp.
94 	 */
95 	getmicrouptime(&tv);
96 	return (tv.tv_sec * 1000 + tv.tv_usec / 1000);
97 }
98 #endif /* _KERNEL */
99 
100 #endif /* _NETINET_TCP_SEQ_H_ */
101