bsd/netinet/tcp.h

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*
  31  * Copyright (c) 1982, 1986, 1993
  32  *      The Regents of the University of California.  All rights reserved.
  33  *
  34  * Redistribution and use in source and binary forms, with or without
  35  * modification, are permitted provided that the following conditions
  36  * are met:
  37  * 1. Redistributions of source code must retain the above copyright
  38  *    notice, this list of conditions and the following disclaimer.
  39  * 2. Redistributions in binary form must reproduce the above copyright
  40  *    notice, this list of conditions and the following disclaimer in the
  41  *    documentation and/or other materials provided with the distribution.
  42  * 3. All advertising materials mentioning features or use of this software
  43  *    must display the following acknowledgement:
  44  *      This product includes software developed by the University of
  45  *      California, Berkeley and its contributors.
  46  * 4. Neither the name of the University nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  60  * SUCH DAMAGE.
  61  *
  62  *      @(#)tcp.h       8.1 (Berkeley) 6/10/93
  63  * $FreeBSD: src/sys/netinet/tcp.h,v 1.13.2.3 2001/03/01 22:08:42 jlemon Exp $
  64  */
  65
  66 #ifndef _NETINET_TCP_H_
  67 #define _NETINET_TCP_H_
  68 #include <sys/appleapiopts.h>
  69 #include <sys/_types.h>
  70 #include <machine/endian.h>
  71
  72 #ifndef _POSIX_C_SOURCE
  73 typedef __uint32_t tcp_seq;
  74 typedef __uint32_t tcp_cc;              /* connection count per rfc1644 */
  75
  76 #define tcp6_seq        tcp_seq /* for KAME src sync over BSD*'s */
  77 #define tcp6hdr         tcphdr  /* for KAME src sync over BSD*'s */
  78
  79 /*
  80  * TCP header.
  81  * Per RFC 793, September, 1981.
  82  */
  83 struct tcphdr {
  84         unsigned short  th_sport;       /* source port */
  85         unsigned short  th_dport;       /* destination port */
  86         tcp_seq th_seq;                 /* sequence number */
  87         tcp_seq th_ack;                 /* acknowledgement number */
  88 #if __DARWIN_BYTE_ORDER == __DARWIN_LITTLE_ENDIAN
  89         unsigned int    th_x2:4,        /* (unused) */
  90                         th_off:4;       /* data offset */
  91 #endif
  92 #if __DARWIN_BYTE_ORDER == __DARWIN_BIG_ENDIAN
  93         unsigned int    th_off:4,       /* data offset */
  94                         th_x2:4;        /* (unused) */
  95 #endif
  96         unsigned char   th_flags;
  97 #define TH_FIN  0x01
  98 #define TH_SYN  0x02
  99 #define TH_RST  0x04
 100 #define TH_PUSH 0x08
 101 #define TH_ACK  0x10
 102 #define TH_URG  0x20
 103 #define TH_ECE  0x40
 104 #define TH_CWR  0x80
 105 #define TH_FLAGS        (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
 106
 107         unsigned short  th_win;         /* window */
 108         unsigned short  th_sum;         /* checksum */
 109         unsigned short  th_urp;         /* urgent pointer */
 110 };
 111
 112 #define TCPOPT_EOL              0
 113 #define TCPOPT_NOP              1
 114 #define TCPOPT_MAXSEG           2
 115 #define TCPOLEN_MAXSEG          4
 116 #define TCPOPT_WINDOW           3
 117 #define TCPOLEN_WINDOW          3
 118 #define TCPOPT_SACK_PERMITTED   4               /* Experimental */
 119 #define    TCPOLEN_SACK_PERMITTED       2
 120 #define TCPOPT_SACK             5               /* Experimental */
 121 #define TCPOLEN_SACK            8               /* len of sack block */
 122 #define TCPOPT_TIMESTAMP        8
 123 #define TCPOLEN_TIMESTAMP       10
 124 #define TCPOLEN_TSTAMP_APPA             (TCPOLEN_TIMESTAMP+2) /* appendix A */
 125 #define TCPOPT_TSTAMP_HDR               \
 126     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
 127
 128 #define MAX_TCPOPTLEN           40      /* Absolute maximum TCP options len */
 129
 130 #define TCPOPT_CC               11              /* CC options: RFC-1644 */
 131 #define TCPOPT_CCNEW            12
 132 #define TCPOPT_CCECHO           13
 133 #define    TCPOLEN_CC                   6
 134 #define    TCPOLEN_CC_APPA              (TCPOLEN_CC+2)
 135 #define    TCPOPT_CC_HDR(ccopt)         \
 136     (TCPOPT_NOP<<24|TCPOPT_NOP<<16|(ccopt)<<8|TCPOLEN_CC)
 137 #define TCPOPT_SIGNATURE                19      /* Keyed MD5: RFC 2385 */
 138 #define    TCPOLEN_SIGNATURE            18
 139
 140 /* Option definitions */
 141 #define TCPOPT_SACK_PERMIT_HDR  \
 142 (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED)
 143 #define TCPOPT_SACK_HDR         (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8)
 144 /* Miscellaneous constants */
 145 #define MAX_SACK_BLKS   6       /* Max # SACK blocks stored at sender side */
 146 #define TCP_MAX_SACK    3       /* MAX # SACKs sent in any segment */
 147
 148
 149 /*
 150  * Default maximum segment size for TCP.
 151  * With an IP MTU of 576, this is 536,
 152  * but 512 is probably more convenient.
 153  * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
 154  */
 155 #define TCP_MSS 512
 156
 157 /*
 158  * TCP_MINMSS is defined to be 216 which is fine for the smallest
 159  * link MTU (256 bytes, SLIP interface) in the Internet.
 160  * However it is very unlikely to come across such low MTU interfaces
 161  * these days (anno dato 2004).
 162  * Probably it can be set to 512 without ill effects. But we play safe.
 163  * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments.
 164  * Setting this to "0" disables the minmss check.
 165  */
 166 #define TCP_MINMSS 216
 167
 168 /*
 169  * TCP_MINMSSOVERLOAD is defined to be 1000 which should cover any type
 170  * of interactive TCP session.
 171  * See tcp_subr.c tcp_minmssoverload SYSCTL declaration and tcp_input.c
 172  * for more comments.
 173  * Setting this to "0" disables the minmssoverload check.
 174  */
 175 #define TCP_MINMSSOVERLOAD 1000
 176
 177 /*
 178  * Default maximum segment size for TCP6.
 179  * With an IP6 MSS of 1280, this is 1220,
 180  * but 1024 is probably more convenient. (xxx kazu in doubt)
 181  * This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr))
 182  */
 183 #define TCP6_MSS        1024
 184
 185 #define TCP_MAXWIN      65535   /* largest value for (unscaled) window */
 186 #define TTCP_CLIENT_SND_WND     4096    /* dflt send window for T/TCP client */
 187
 188 #define TCP_MAX_WINSHIFT        14      /* maximum window shift */
 189
 190 #define TCP_MAXBURST            4       /* maximum segments in a burst */
 191
 192 #define TCP_MAXHLEN     (0xf<<2)        /* max length of header in bytes */
 193 #define TCP_MAXOLEN     (TCP_MAXHLEN - sizeof(struct tcphdr))
 194                                         /* max space left for options */
 195 #endif /* _POSIX_C_SOURCE */
 196
 197 /*
 198  * User-settable options (used with setsockopt).
 199  */
 200 #define TCP_NODELAY     0x01    /* don't delay send to coalesce packets */
 201 #ifndef _POSIX_C_SOURCE
 202 #define TCP_MAXSEG              0x02    /* set maximum segment size */
 203 #define TCP_NOPUSH              0x04    /* don't push last block of write */
 204 #define TCP_NOOPT               0x08    /* don't use TCP options */
 205 #define TCP_KEEPALIVE   0x10    /* idle time used when SO_KEEPALIVE is enabled */
 206 #endif /* _POSIX_C_SOURCE */
 207
 208 #endif