The Tcpdump Group git mirrors - tcpdump/blob - linux-include/netinet/ip.h

   1 /*
   2  * Copyright (c) 1982, 1986, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)ip.h        8.2 (Berkeley) 6/1/94
  34  */
  35
  36 #include <endian.h>
  37
  38 /*
  39  * Definitions for internet protocol version 4.
  40  * Per RFC 791, September 1981.
  41  */
  42 #define IPVERSION       4
  43
  44 /*
  45  * Structure of an internet header, naked of options.
  46  *
  47  * We declare ip_len and ip_off to be short, rather than u_short
  48  * pragmatically since otherwise unsigned comparisons can result
  49  * against negative integers quite easily, and fail in subtle ways.
  50  */
  51 struct ip {
  52 #if BYTE_ORDER == LITTLE_ENDIAN
  53         u_char  ip_hl:4,                /* header length */
  54                 ip_v:4;                 /* version */
  55 #endif
  56 #if BYTE_ORDER == BIG_ENDIAN
  57         u_char  ip_v:4,                 /* version */
  58                 ip_hl:4;                /* header length */
  59 #endif
  60         u_char  ip_tos;                 /* type of service */
  61         short   ip_len;                 /* total length */
  62         u_short ip_id;                  /* identification */
  63         short   ip_off;                 /* fragment offset field */
  64 #define IP_DF 0x4000                    /* dont fragment flag */
  65 #define IP_MF 0x2000                    /* more fragments flag */
  66 #define IP_OFFMASK 0x1fff               /* mask for fragmenting bits */
  67         u_char  ip_ttl;                 /* time to live */
  68         u_char  ip_p;                   /* protocol */
  69         u_short ip_sum;                 /* checksum */
  70         struct  in_addr ip_src,ip_dst;  /* source and dest address */
  71 };
  72
  73 #define IP_MAXPACKET    65535           /* maximum packet size */
  74
  75 /*
  76  * Definitions for IP type of service (ip_tos)
  77  */
  78 #define IPTOS_LOWDELAY          0x10
  79 #define IPTOS_THROUGHPUT        0x08
  80 #define IPTOS_RELIABILITY       0x04
  81
  82 /*
  83  * Definitions for IP precedence (also in ip_tos) (hopefully unused)
  84  */
  85 #define IPTOS_PREC_NETCONTROL           0xe0
  86 #define IPTOS_PREC_INTERNETCONTROL      0xc0
  87 #define IPTOS_PREC_CRITIC_ECP           0xa0
  88 #define IPTOS_PREC_FLASHOVERRIDE        0x80
  89 #define IPTOS_PREC_FLASH                0x60
  90 #define IPTOS_PREC_IMMEDIATE            0x40
  91 #define IPTOS_PREC_PRIORITY             0x20
  92 #define IPTOS_PREC_ROUTINE              0x00
  93
  94 /*
  95  * Definitions for options.
  96  */
  97 #define IPOPT_COPIED(o)         ((o)&0x80)
  98 #define IPOPT_CLASS(o)          ((o)&0x60)
  99 #define IPOPT_NUMBER(o)         ((o)&0x1f)
 100
 101 #define IPOPT_CONTROL           0x00
 102 #define IPOPT_RESERVED1         0x20
 103 #define IPOPT_DEBMEAS           0x40
 104 #define IPOPT_RESERVED2         0x60
 105
 106 #define IPOPT_EOL               0               /* end of option list */
 107 #define IPOPT_NOP               1               /* no operation */
 108
 109 #define IPOPT_RR                7               /* record packet route */
 110 #define IPOPT_TS                68              /* timestamp */
 111 #define IPOPT_SECURITY          130             /* provide s,c,h,tcc */
 112 #define IPOPT_LSRR              131             /* loose source route */
 113 #define IPOPT_SATID             136             /* satnet id */
 114 #define IPOPT_SSRR              137             /* strict source route */
 115
 116 /*
 117  * Offsets to fields in options other than EOL and NOP.
 118  */
 119 #define IPOPT_OPTVAL            0               /* option ID */
 120 #define IPOPT_OLEN              1               /* option length */
 121 #define IPOPT_OFFSET            2               /* offset within option */
 122 #define IPOPT_MINOFF            4               /* min value of above */
 123
 124 /*
 125  * Time stamp option structure.
 126  */
 127 struct  ip_timestamp {
 128         u_char  ipt_code;               /* IPOPT_TS */
 129         u_char  ipt_len;                /* size of structure (variable) */
 130         u_char  ipt_ptr;                /* index of current entry */
 131 #if BYTE_ORDER == LITTLE_ENDIAN
 132         u_char  ipt_flg:4,              /* flags, see below */
 133                 ipt_oflw:4;             /* overflow counter */
 134 #endif
 135 #if BYTE_ORDER == BIG_ENDIAN
 136         u_char  ipt_oflw:4,             /* overflow counter */
 137                 ipt_flg:4;              /* flags, see below */
 138 #endif
 139         union ipt_timestamp {
 140                 n_long  ipt_time[1];
 141                 struct  ipt_ta {
 142                         struct in_addr ipt_addr;
 143                         n_long ipt_time;
 144                 } ipt_ta[1];
 145         } ipt_timestamp;
 146 };
 147
 148 /* flag bits for ipt_flg */
 149 #define IPOPT_TS_TSONLY         0               /* timestamps only */
 150 #define IPOPT_TS_TSANDADDR      1               /* timestamps and addresses */
 151 #define IPOPT_TS_PRESPEC        3               /* specified modules only */
 152
 153 /* bits for security (not byte swapped) */
 154 #define IPOPT_SECUR_UNCLASS     0x0000
 155 #define IPOPT_SECUR_CONFID      0xf135
 156 #define IPOPT_SECUR_EFTO        0x789a
 157 #define IPOPT_SECUR_MMMM        0xbc4d
 158 #define IPOPT_SECUR_RESTR       0xaf13
 159 #define IPOPT_SECUR_SECRET      0xd788
 160 #define IPOPT_SECUR_TOPSECRET   0x6bc5
 161
 162 /*
 163  * Internet implementation parameters.
 164  */
 165 #define MAXTTL          255             /* maximum time to live (seconds) */
 166 #define IPDEFTTL        64              /* default ttl, from RFC 1340 */
 167 #define IPFRAGTTL       60              /* time to live for frags, slowhz */
 168 #define IPTTLDEC        1               /* subtracted when forwarding */
 169
 170 #define IP_MSS          576             /* default maximum segment size */