bsd/netinet/tcp.h

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * Copyright (c) 1982, 1986, 1993
  30  *      The Regents of the University of California.  All rights reserved.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  * 3. All advertising materials mentioning features or use of this software
  41  *    must display the following acknowledgement:
  42  *      This product includes software developed by the University of
  43  *      California, Berkeley and its contributors.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  *
  60  *      @(#)tcp.h       8.1 (Berkeley) 6/10/93
  61  * $FreeBSD: src/sys/netinet/tcp.h,v 1.13.2.3 2001/03/01 22:08:42 jlemon Exp $
  62  */
  63
  64 #ifndef _NETINET_TCP_H_
  65 #define _NETINET_TCP_H_
  66 #include <sys/appleapiopts.h>
  67 #include <sys/_types.h>
  68 #include <machine/endian.h>
  69
  70 #if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
  71 typedef __uint32_t tcp_seq;
  72 typedef __uint32_t tcp_cc;              /* connection count per rfc1644 */
  73
  74 #define tcp6_seq        tcp_seq /* for KAME src sync over BSD*'s */
  75 #define tcp6hdr         tcphdr  /* for KAME src sync over BSD*'s */
  76
  77 /*
  78  * TCP header.
  79  * Per RFC 793, September, 1981.
  80  */
  81 struct tcphdr {
  82         unsigned short  th_sport;       /* source port */
  83         unsigned short  th_dport;       /* destination port */
  84         tcp_seq th_seq;                 /* sequence number */
  85         tcp_seq th_ack;                 /* acknowledgement number */
  86 #if __DARWIN_BYTE_ORDER == __DARWIN_LITTLE_ENDIAN
  87         unsigned int    th_x2:4,        /* (unused) */
  88                         th_off:4;       /* data offset */
  89 #endif
  90 #if __DARWIN_BYTE_ORDER == __DARWIN_BIG_ENDIAN
  91         unsigned int    th_off:4,       /* data offset */
  92                         th_x2:4;        /* (unused) */
  93 #endif
  94         unsigned char   th_flags;
  95 #define TH_FIN  0x01
  96 #define TH_SYN  0x02
  97 #define TH_RST  0x04
  98 #define TH_PUSH 0x08
  99 #define TH_ACK  0x10
 100 #define TH_URG  0x20
 101 #define TH_ECE  0x40
 102 #define TH_CWR  0x80
 103 #define TH_FLAGS        (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
 104
 105         unsigned short  th_win;         /* window */
 106         unsigned short  th_sum;         /* checksum */
 107         unsigned short  th_urp;         /* urgent pointer */
 108 };
 109
 110 #define TCPOPT_EOL              0
 111 #define TCPOPT_NOP              1
 112 #define TCPOPT_MAXSEG           2
 113 #define TCPOLEN_MAXSEG          4
 114 #define TCPOPT_WINDOW           3
 115 #define TCPOLEN_WINDOW          3
 116 #define TCPOPT_SACK_PERMITTED   4               /* Experimental */
 117 #define TCPOLEN_SACK_PERMITTED  2
 118 #define TCPOPT_SACK             5               /* Experimental */
 119 #define TCPOLEN_SACK            8               /* len of sack block */
 120 #define TCPOPT_TIMESTAMP        8
 121 #define TCPOLEN_TIMESTAMP       10
 122 #define TCPOLEN_TSTAMP_APPA             (TCPOLEN_TIMESTAMP+2) /* appendix A */
 123 #define TCPOPT_TSTAMP_HDR               \
 124     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
 125
 126 #define MAX_TCPOPTLEN           40      /* Absolute maximum TCP options len */
 127
 128 #define TCPOPT_CC               11              /* CC options: RFC-1644 */
 129 #define TCPOPT_CCNEW            12
 130 #define TCPOPT_CCECHO           13
 131 #define    TCPOLEN_CC                   6
 132 #define    TCPOLEN_CC_APPA              (TCPOLEN_CC+2)
 133 #define    TCPOPT_CC_HDR(ccopt)         \
 134     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|(ccopt)<<8|TCPOLEN_CC)
 135 #define TCPOPT_SIGNATURE                19      /* Keyed MD5: RFC 2385 */
 136 #define    TCPOLEN_SIGNATURE            18
 137
 138 /* Option definitions */
 139 #define TCPOPT_SACK_PERMIT_HDR  \
 140 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED)
 141 #define TCPOPT_SACK_HDR         (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8)
 142 /* Miscellaneous constants */
 143 #define MAX_SACK_BLKS   6       /* Max # SACK blocks stored at sender side */
 144 #define TCP_MAX_SACK    3       /* MAX # SACKs sent in any segment */
 145
 146
 147 /*
 148  * Default maximum segment size for TCP.
 149  * With an IP MTU of 576, this is 536,
 150  * but 512 is probably more convenient.
 151  * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
 152  */
 153 #define TCP_MSS 512
 154
 155 /*
 156  * TCP_MINMSS is defined to be 216 which is fine for the smallest
 157  * link MTU (256 bytes, SLIP interface) in the Internet.
 158  * However it is very unlikely to come across such low MTU interfaces
 159  * these days (anno dato 2004).
 160  * Probably it can be set to 512 without ill effects. But we play safe.
 161  * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments.
 162  * Setting this to "0" disables the minmss check.
 163  */
 164 #define TCP_MINMSS 216
 165
 166 /*
 167  * TCP_MINMSSOVERLOAD is defined to be 1000 which should cover any type
 168  * of interactive TCP session.
 169  * See tcp_subr.c tcp_minmssoverload SYSCTL declaration and tcp_input.c
 170  * for more comments.
 171  * Setting this to "0" disables the minmssoverload check.
 172  */
 173 #define TCP_MINMSSOVERLOAD 1000
 174
 175 /*
 176  * Default maximum segment size for TCP6.
 177  * With an IP6 MSS of 1280, this is 1220,
 178  * but 1024 is probably more convenient. (xxx kazu in doubt)
 179  * This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr))
 180  */
 181 #define TCP6_MSS        1024
 182
 183 #define TCP_MAXWIN      65535   /* largest value for (unscaled) window */
 184 #define TTCP_CLIENT_SND_WND     4096    /* dflt send window for T/TCP client */
 185
 186 #define TCP_MAX_WINSHIFT        14      /* maximum window shift */
 187
 188 #define TCP_MAXBURST            4       /* maximum segments in a burst */
 189
 190 #define TCP_MAXHLEN     (0xf<<2)        /* max length of header in bytes */
 191 #define TCP_MAXOLEN     (TCP_MAXHLEN - sizeof(struct tcphdr))
 192                                         /* max space left for options */
 193 #endif /* (_POSIX_C_SOURCE && !_DARWIN_C_SOURCE) */
 194
 195 /*
 196  * User-settable options (used with setsockopt).
 197  */
 198 #define TCP_NODELAY     0x01    /* don't delay send to coalesce packets */
 199 #if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
 200 #define TCP_MAXSEG      0x02    /* set maximum segment size */
 201 #define TCP_NOPUSH      0x04    /* don't push last block of write */
 202 #define TCP_NOOPT       0x08    /* don't use TCP options */
 203 #define TCP_KEEPALIVE   0x10    /* idle time used when SO_KEEPALIVE is enabled */
 204 #endif /* (_POSIX_C_SOURCE && !_DARWIN_C_SOURCE) */
 205
 206 #endif