FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp_seq.h
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: releng/8.4/sys/netinet/tcp_seq.h 235658 2012-05-19 18:33:08Z bz $
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_ */
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