bsd/netinet/tcp_seq.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1982, 1986, 1993, 1995
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  * 3. All advertising materials mentioning features or use of this software
  35  *    must display the following acknowledgement:
  36  *      This product includes software developed by the University of
  37  *      California, Berkeley and its contributors.
  38  * 4. Neither the name of the University nor the names of its contributors
  39  *    may be used to endorse or promote products derived from this software
  40  *    without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  *
  54  *      @(#)tcp_seq.h   8.3 (Berkeley) 6/21/95
  55  */
  56
  57 #ifndef _NETINET_TCP_SEQ_H_
  58 #define _NETINET_TCP_SEQ_H_
  59 /*
  60  * TCP sequence numbers are 32 bit integers operated
  61  * on with modular arithmetic.  These macros can be
  62  * used to compare such integers.
  63  */
  64 #define SEQ_LT(a,b)     ((int)((a)-(b)) < 0)
  65 #define SEQ_LEQ(a,b)    ((int)((a)-(b)) <= 0)
  66 #define SEQ_GT(a,b)     ((int)((a)-(b)) > 0)
  67 #define SEQ_GEQ(a,b)    ((int)((a)-(b)) >= 0)
  68
  69 /* for modulo comparisons of timestamps */
  70 #define TSTMP_LT(a,b)   ((int)((a)-(b)) < 0)
  71 #define TSTMP_GEQ(a,b)  ((int)((a)-(b)) >= 0)
  72
  73 /*
  74  * TCP connection counts are 32 bit integers operated
  75  * on with modular arithmetic.  These macros can be
  76  * used to compare such integers.
  77  */
  78 #define CC_LT(a,b)      ((int)((a)-(b)) < 0)
  79 #define CC_LEQ(a,b)     ((int)((a)-(b)) <= 0)
  80 #define CC_GT(a,b)      ((int)((a)-(b)) > 0)
  81 #define CC_GEQ(a,b)     ((int)((a)-(b)) >= 0)
  82
  83 /* Macro to increment a CC: skip 0 which has a special meaning */
  84 #define CC_INC(c)       (++(c) == 0 ? ++(c) : (c))
  85
  86 /*
  87  * Macros to initialize tcp sequence numbers for
  88  * send and receive from initial send and receive
  89  * sequence numbers.
  90  */
  91 #define tcp_rcvseqinit(tp) \
  92         (tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
  93
  94 #define tcp_sendseqinit(tp) \
  95         (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
  96             (tp)->iss
  97
  98 #define TCP_PAWS_IDLE   (24 * 24 * 60 * 60 * PR_SLOWHZ)
  99                                         /* timestamp wrap-around time */
 100
 101 #ifdef KERNEL
 102 extern tcp_cc   tcp_ccgen;              /* global connection count */
 103
 104 /*
 105  * Increment for tcp_iss each second.
 106  * This is designed to increment at the standard 250 KB/s,
 107  * but with a random component averaging 128 KB.
 108  * We also increment tcp_iss by a quarter of this amount
 109  * each time we use the value for a new connection.
 110  * If defined, the tcp_random18() macro should produce a
 111  * number in the range [0-0x3ffff] that is hard to predict.
 112  */
 113 #ifndef tcp_random18
 114 #define tcp_random18()  ((random() >> 14) & 0x3ffff)
 115 #endif
 116 #define TCP_ISSINCR     (122*1024 + tcp_random18())
 117
 118 extern tcp_seq  tcp_iss;                /* tcp initial send seq # */
 119 #else
 120 #define TCP_ISSINCR     (250*1024)      /* increment for tcp_iss each second */
 121 #endif /* KERNEL */
 122 #endif /* _NETINET_TCP_SEQ_H_ */