bsd/netinet/tcp.h

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