The Tcpdump Group git mirrors - tcpdump/blob - 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 /*
  37  * Definitions for internet protocol version 4.
  38  * Per RFC 791, September 1981.
  39  */
  40 #define IPVERSION       4
  41
  42 /*
  43  * Structure of an internet header, naked of options.
  44  *
  45  * We declare ip_len and ip_off to be short, rather than u_short
  46  * pragmatically since otherwise unsigned comparisons can result
  47  * against negative integers quite easily, and fail in subtle ways.
  48  */
  49 struct ip {
  50         u_int8_t        ip_vhl;         /* header length, version */
  51 #define IP_V(ip)        (((ip)->ip_vhl & 0xf0) >> 4)
  52 #define IP_HL(ip)       ((ip)->ip_vhl & 0x0f)
  53         u_int8_t        ip_tos;         /* type of service */
  54         u_int16_t       ip_len;         /* total length */
  55         u_int16_t       ip_id;          /* identification */
  56         u_int16_t       ip_off;         /* fragment offset field */
  57 #define IP_DF 0x4000                    /* dont fragment flag */
  58 #define IP_MF 0x2000                    /* more fragments flag */
  59 #define IP_OFFMASK 0x1fff               /* mask for fragmenting bits */
  60         u_int8_t        ip_ttl;         /* time to live */
  61         u_int8_t        ip_p;           /* protocol */
  62         u_int16_t       ip_sum;         /* checksum */
  63         struct  in_addr ip_src,ip_dst;  /* source and dest address */
  64 } UNALIGNED;
  65
  66 #define IP_MAXPACKET    65535           /* maximum packet size */
  67
  68 /*
  69  * Definitions for IP type of service (ip_tos)
  70  */
  71 #define IPTOS_LOWDELAY          0x10
  72 #define IPTOS_THROUGHPUT        0x08
  73 #define IPTOS_RELIABILITY       0x04
  74
  75 /*
  76  * Definitions for IP precedence (also in ip_tos) (hopefully unused)
  77  */
  78 #define IPTOS_PREC_NETCONTROL           0xe0
  79 #define IPTOS_PREC_INTERNETCONTROL      0xc0
  80 #define IPTOS_PREC_CRITIC_ECP           0xa0
  81 #define IPTOS_PREC_FLASHOVERRIDE        0x80
  82 #define IPTOS_PREC_FLASH                0x60
  83 #define IPTOS_PREC_IMMEDIATE            0x40
  84 #define IPTOS_PREC_PRIORITY             0x20
  85 #define IPTOS_PREC_ROUTINE              0x00
  86
  87 /*
  88  * Definitions for options.
  89  */
  90 #define IPOPT_COPIED(o)         ((o)&0x80)
  91 #define IPOPT_CLASS(o)          ((o)&0x60)
  92 #define IPOPT_NUMBER(o)         ((o)&0x1f)
  93
  94 #define IPOPT_CONTROL           0x00
  95 #define IPOPT_RESERVED1         0x20
  96 #define IPOPT_DEBMEAS           0x40
  97 #define IPOPT_RESERVED2         0x60
  98
  99 #define IPOPT_EOL               0               /* end of option list */
 100 #define IPOPT_NOP               1               /* no operation */
 101
 102 #define IPOPT_RR                7               /* record packet route */
 103 #define IPOPT_TS                68              /* timestamp */
 104 #define IPOPT_RFC1393           82              /* traceroute RFC 1393 */
 105 #define IPOPT_SECURITY          130             /* provide s,c,h,tcc */
 106 #define IPOPT_LSRR              131             /* loose source route */
 107 #define IPOPT_SATID             136             /* satnet id */
 108 #define IPOPT_SSRR              137             /* strict source route */
 109 #define IPOPT_RA                148             /* router-alert, rfc2113 */
 110
 111 /*
 112  * Offsets to fields in options other than EOL and NOP.
 113  */
 114 #define IPOPT_OPTVAL            0               /* option ID */
 115 #define IPOPT_OLEN              1               /* option length */
 116 #define IPOPT_OFFSET            2               /* offset within option */
 117 #define IPOPT_MINOFF            4               /* min value of above */
 118
 119 /*
 120  * Time stamp option structure.
 121  */
 122 struct  ip_timestamp {
 123         u_int8_t        ipt_code;       /* IPOPT_TS */
 124         u_int8_t        ipt_len;        /* size of structure (variable) */
 125         u_int8_t        ipt_ptr;        /* index of current entry */
 126         u_int8_t        ipt_oflwflg;    /* flags, overflow counter */
 127 #define IPTS_OFLW(ip)   (((ipt)->ipt_oflwflg & 0xf0) >> 4)
 128 #define IPTS_FLG(ip)    ((ipt)->ipt_oflwflg & 0x0f)
 129         union ipt_timestamp {
 130                 u_int32_t ipt_time[1];
 131                 struct  ipt_ta {
 132                         struct in_addr ipt_addr;
 133                         u_int32_t ipt_time;
 134                 } ipt_ta[1];
 135         } ipt_timestamp;
 136 } UNALIGNED;
 137
 138 /* flag bits for ipt_flg */
 139 #define IPOPT_TS_TSONLY         0               /* timestamps only */
 140 #define IPOPT_TS_TSANDADDR      1               /* timestamps and addresses */
 141 #define IPOPT_TS_PRESPEC        3               /* specified modules only */
 142
 143 /* bits for security (not byte swapped) */
 144 #define IPOPT_SECUR_UNCLASS     0x0000
 145 #define IPOPT_SECUR_CONFID      0xf135
 146 #define IPOPT_SECUR_EFTO        0x789a
 147 #define IPOPT_SECUR_MMMM        0xbc4d
 148 #define IPOPT_SECUR_RESTR       0xaf13
 149 #define IPOPT_SECUR_SECRET      0xd788
 150 #define IPOPT_SECUR_TOPSECRET   0x6bc5
 151
 152 /*
 153  * Internet implementation parameters.
 154  */
 155 #define MAXTTL          255             /* maximum time to live (seconds) */
 156 #define IPDEFTTL        64              /* default ttl, from RFC 1340 */
 157 #define IPFRAGTTL       60              /* time to live for frags, slowhz */
 158 #define IPTTLDEC        1               /* subtracted when forwarding */
 159
 160 #define IP_MSS          576             /* default maximum segment size */
 161
 162 /* in print-ip.c */
 163 extern int nextproto4_cksum(const struct ip *, const u_int8_t *, u_int, u_int, u_int);