1 /*!\file netinet/tcp_seq.h
2 * TCP serquence number handling.
6 * Copyright (c) 1982, 1986, 1993, 1995
7 * The Regents of the University of California. All rights reserved.
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19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
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37 * @(#)tcp_seq.h 8.3 (Berkeley) 6/21/95
38 * $Id: tcp_seq.h,v 1.6 1995/10/03 16:54:14 wollman Exp $
41 #ifndef __NETINET_TCP_SEQ_H
42 #define __NETINET_TCP_SEQ_H
45 * TCP sequence numbers are 32 bit integers operated
46 * on with modular arithmetic. These macros can be
47 * used to compare such integers.
49 #define SEQ_LT(a,b) ((long)((a)-(b)) < 0)
50 #define SEQ_LEQ(a,b) ((long)((a)-(b)) <= 0)
51 #define SEQ_GT(a,b) ((long)((a)-(b)) > 0)
52 #define SEQ_GEQ(a,b) ((long)((a)-(b)) >= 0)
54 /* for modulo comparisons of timestamps */
55 #define TSTMP_LT(a,b) ((long)((a)-(b)) < 0)
56 #define TSTMP_GEQ(a,b) ((long)((a)-(b)) >= 0)
59 * TCP connection counts are 32 bit integers operated
60 * on with modular arithmetic. These macros can be
61 * used to compare such integers.
63 #define CC_LT(a,b) ((long)((a)-(b)) < 0)
64 #define CC_LEQ(a,b) ((long)((a)-(b)) <= 0)
65 #define CC_GT(a,b) ((long)((a)-(b)) > 0)
66 #define CC_GEQ(a,b) ((long)((a)-(b)) >= 0)
68 /* Macro to increment a CC: skip 0 which has a special meaning */
69 #define CC_INC(c) (++(c) == 0 ? ++(c) : (c))
72 * Macros to initialize tcp sequence numbers for
73 * send and receive from initial send and receive
76 #define tcp_rcvseqinit(tp) \
77 (tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
80 #define tcp_sendseqinit(tp) \
81 (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
82 (tp)->recover = (tp)->sb.last_ack = (tp)->iss
84 #elif defined(TCP_FACK)
85 #define tcp_sendseqinit(tp) \
86 (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
87 (tp)->recover = (tp)->scrb.last_ack = (tp)->snd_fack = (tp)->iss
90 #define tcp_sendseqinit(tp) \
91 (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
95 #define TCP_PAWS_IDLE (24 * 24 * 60 * 60 * PR_SLOWHZ)
96 /* timestamp wrap-around time */
98 #define TCP_ISSINCR (125*1024) /* increment for tcp_iss each second */
101 tcp_seq tcp_iss; /* tcp initial send seq # */