bsd/netinet/tcp.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
  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.h       8.1 (Berkeley) 6/10/93
  55  * $FreeBSD: src/sys/netinet/tcp.h,v 1.13.2.3 2001/03/01 22:08:42 jlemon Exp $
  56  */
  57
  58 #ifndef _NETINET_TCP_H_
  59 #define _NETINET_TCP_H_
  60 #include <sys/appleapiopts.h>
  61
  62 typedef u_int32_t tcp_seq;
  63 typedef u_int32_t tcp_cc;               /* connection count per rfc1644 */
  64
  65 #define tcp6_seq        tcp_seq /* for KAME src sync over BSD*'s */
  66 #define tcp6hdr         tcphdr  /* for KAME src sync over BSD*'s */
  67
  68 /*
  69  * TCP header.
  70  * Per RFC 793, September, 1981.
  71  */
  72 struct tcphdr {
  73         u_short th_sport;               /* source port */
  74         u_short th_dport;               /* destination port */
  75         tcp_seq th_seq;                 /* sequence number */
  76         tcp_seq th_ack;                 /* acknowledgement number */
  77 #if BYTE_ORDER == LITTLE_ENDIAN
  78         u_int   th_x2:4,                /* (unused) */
  79                 th_off:4;               /* data offset */
  80 #endif
  81 #if BYTE_ORDER == BIG_ENDIAN
  82         u_int   th_off:4,               /* data offset */
  83                 th_x2:4;                /* (unused) */
  84 #endif
  85         u_char  th_flags;
  86 #define TH_FIN  0x01
  87 #define TH_SYN  0x02
  88 #define TH_RST  0x04
  89 #define TH_PUSH 0x08
  90 #define TH_ACK  0x10
  91 #define TH_URG  0x20
  92 #define TH_ECE  0x40
  93 #define TH_CWR  0x80
  94 #define TH_FLAGS        (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
  95
  96         u_short th_win;                 /* window */
  97         u_short th_sum;                 /* checksum */
  98         u_short th_urp;                 /* urgent pointer */
  99 };
 100
 101 #define TCPOPT_EOL              0
 102 #define TCPOPT_NOP              1
 103 #define TCPOPT_MAXSEG           2
 104 #define    TCPOLEN_MAXSEG               4
 105 #define TCPOPT_WINDOW           3
 106 #define    TCPOLEN_WINDOW               3
 107 #define TCPOPT_SACK_PERMITTED   4               /* Experimental */
 108 #define    TCPOLEN_SACK_PERMITTED       2
 109 #define TCPOPT_SACK             5               /* Experimental */
 110 #define TCPOPT_TIMESTAMP        8
 111 #define    TCPOLEN_TIMESTAMP            10
 112 #define    TCPOLEN_TSTAMP_APPA          (TCPOLEN_TIMESTAMP+2) /* appendix A */
 113 #define    TCPOPT_TSTAMP_HDR            \
 114     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
 115
 116 #define TCPOPT_CC               11              /* CC options: RFC-1644 */
 117 #define TCPOPT_CCNEW            12
 118 #define TCPOPT_CCECHO           13
 119 #define    TCPOLEN_CC                   6
 120 #define    TCPOLEN_CC_APPA              (TCPOLEN_CC+2)
 121 #define    TCPOPT_CC_HDR(ccopt)         \
 122     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|(ccopt)<<8|TCPOLEN_CC)
 123
 124 /*
 125  * Default maximum segment size for TCP.
 126  * With an IP MTU of 576, this is 536,
 127  * but 512 is probably more convenient.
 128  * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
 129  */
 130 #define TCP_MSS 512
 131
 132 /*
 133  * TCP_MINMSS is defined to be 216 which is fine for the smallest
 134  * link MTU (256 bytes, SLIP interface) in the Internet.
 135  * However it is very unlikely to come across such low MTU interfaces
 136  * these days (anno dato 2004).
 137  * Probably it can be set to 512 without ill effects. But we play safe.
 138  * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments.
 139  * Setting this to "0" disables the minmss check.
 140  */
 141 #define TCP_MINMSS 216
 142
 143 /*
 144  * Default maximum segment size for TCP6.
 145  * With an IP6 MSS of 1280, this is 1220,
 146  * but 1024 is probably more convenient. (xxx kazu in doubt)
 147  * This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr))
 148  */
 149 #define TCP6_MSS        1024
 150
 151 #define TCP_MAXWIN      65535   /* largest value for (unscaled) window */
 152 #define TTCP_CLIENT_SND_WND     4096    /* dflt send window for T/TCP client */
 153
 154 #define TCP_MAX_WINSHIFT        14      /* maximum window shift */
 155
 156 #define TCP_MAXBURST            4       /* maximum segments in a burst */
 157
 158 #define TCP_MAXHLEN     (0xf<<2)        /* max length of header in bytes */
 159 #define TCP_MAXOLEN     (TCP_MAXHLEN - sizeof(struct tcphdr))
 160                                         /* max space left for options */
 161
 162 /*
 163  * User-settable options (used with setsockopt).
 164  */
 165 #define TCP_NODELAY     0x01    /* don't delay send to coalesce packets */
 166 #define TCP_MAXSEG      0x02    /* set maximum segment size */
 167 #define TCP_NOPUSH      0x04    /* don't push last block of write */
 168 #define TCP_NOOPT       0x08    /* don't use TCP options */
 169 #define TCP_KEEPALIVE   0x10    /* idle time used when SO_KEEPALIVE is enabled */
 170
 171 #endif