1 /* @(#) $Header: /tcpdump/master/tcpdump/ip.h,v 1.11.2.1 2007/09/14 01:30:02 guy Exp $ (LBL) */ 2 /* 3 * Copyright (c) 1982, 1986, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by the University of 17 * California, Berkeley and its contributors. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)ip.h 8.2 (Berkeley) 6/1/94 35 */ 36 37 /* 38 * Definitions for internet protocol version 4. 39 * Per RFC 791, September 1981. 40 */ 41 #define IPVERSION 4 42 43 /* 44 * Structure of an internet header, naked of options. 45 * 46 * We declare ip_len and ip_off to be short, rather than u_short 47 * pragmatically since otherwise unsigned comparisons can result 48 * against negative integers quite easily, and fail in subtle ways. 49 */ 50 struct ip { 51 u_int8_t ip_vhl; /* header length, version */ 52 #define IP_V(ip) (((ip)->ip_vhl & 0xf0) >> 4) 53 #define IP_HL(ip) ((ip)->ip_vhl & 0x0f) 54 u_int8_t ip_tos; /* type of service */ 55 u_int16_t ip_len; /* total length */ 56 u_int16_t ip_id; /* identification */ 57 u_int16_t ip_off; /* fragment offset field */ 58 #define IP_DF 0x4000 /* dont fragment flag */ 59 #define IP_MF 0x2000 /* more fragments flag */ 60 #define IP_OFFMASK 0x1fff /* mask for fragmenting bits */ 61 u_int8_t ip_ttl; /* time to live */ 62 u_int8_t ip_p; /* protocol */ 63 u_int16_t ip_sum; /* checksum */ 64 struct in_addr ip_src,ip_dst; /* source and dest address */ 65 }; 66 67 #define IP_MAXPACKET 65535 /* maximum packet size */ 68 69 /* 70 * Definitions for IP type of service (ip_tos) 71 */ 72 #define IPTOS_LOWDELAY 0x10 73 #define IPTOS_THROUGHPUT 0x08 74 #define IPTOS_RELIABILITY 0x04 75 76 /* 77 * Definitions for IP precedence (also in ip_tos) (hopefully unused) 78 */ 79 #define IPTOS_PREC_NETCONTROL 0xe0 80 #define IPTOS_PREC_INTERNETCONTROL 0xc0 81 #define IPTOS_PREC_CRITIC_ECP 0xa0 82 #define IPTOS_PREC_FLASHOVERRIDE 0x80 83 #define IPTOS_PREC_FLASH 0x60 84 #define IPTOS_PREC_IMMEDIATE 0x40 85 #define IPTOS_PREC_PRIORITY 0x20 86 #define IPTOS_PREC_ROUTINE 0x00 87 88 /* 89 * Definitions for options. 90 */ 91 #define IPOPT_COPIED(o) ((o)&0x80) 92 #define IPOPT_CLASS(o) ((o)&0x60) 93 #define IPOPT_NUMBER(o) ((o)&0x1f) 94 95 #define IPOPT_CONTROL 0x00 96 #define IPOPT_RESERVED1 0x20 97 #define IPOPT_DEBMEAS 0x40 98 #define IPOPT_RESERVED2 0x60 99 100 #define IPOPT_EOL 0 /* end of option list */ 101 #define IPOPT_NOP 1 /* no operation */ 102 103 #define IPOPT_RR 7 /* record packet route */ 104 #define IPOPT_TS 68 /* timestamp */ 105 #define IPOPT_RFC1393 82 /* traceroute RFC 1393 */ 106 #define IPOPT_SECURITY 130 /* provide s,c,h,tcc */ 107 #define IPOPT_LSRR 131 /* loose source route */ 108 #define IPOPT_SATID 136 /* satnet id */ 109 #define IPOPT_SSRR 137 /* strict source route */ 110 #define IPOPT_RA 148 /* router-alert, rfc2113 */ 111 112 /* 113 * Offsets to fields in options other than EOL and NOP. 114 */ 115 #define IPOPT_OPTVAL 0 /* option ID */ 116 #define IPOPT_OLEN 1 /* option length */ 117 #define IPOPT_OFFSET 2 /* offset within option */ 118 #define IPOPT_MINOFF 4 /* min value of above */ 119 120 /* 121 * Time stamp option structure. 122 */ 123 struct ip_timestamp { 124 u_int8_t ipt_code; /* IPOPT_TS */ 125 u_int8_t ipt_len; /* size of structure (variable) */ 126 u_int8_t ipt_ptr; /* index of current entry */ 127 u_int8_t ipt_oflwflg; /* flags, overflow counter */ 128 #define IPTS_OFLW(ip) (((ipt)->ipt_oflwflg & 0xf0) >> 4) 129 #define IPTS_FLG(ip) ((ipt)->ipt_oflwflg & 0x0f) 130 union ipt_timestamp { 131 u_int32_t ipt_time[1]; 132 struct ipt_ta { 133 struct in_addr ipt_addr; 134 u_int32_t ipt_time; 135 } ipt_ta[1]; 136 } ipt_timestamp; 137 }; 138 139 /* flag bits for ipt_flg */ 140 #define IPOPT_TS_TSONLY 0 /* timestamps only */ 141 #define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ 142 #define IPOPT_TS_PRESPEC 3 /* specified modules only */ 143 144 /* bits for security (not byte swapped) */ 145 #define IPOPT_SECUR_UNCLASS 0x0000 146 #define IPOPT_SECUR_CONFID 0xf135 147 #define IPOPT_SECUR_EFTO 0x789a 148 #define IPOPT_SECUR_MMMM 0xbc4d 149 #define IPOPT_SECUR_RESTR 0xaf13 150 #define IPOPT_SECUR_SECRET 0xd788 151 #define IPOPT_SECUR_TOPSECRET 0x6bc5 152 153 /* 154 * Internet implementation parameters. 155 */ 156 #define MAXTTL 255 /* maximum time to live (seconds) */ 157 #define IPDEFTTL 64 /* default ttl, from RFC 1340 */ 158 #define IPFRAGTTL 60 /* time to live for frags, slowhz */ 159 #define IPTTLDEC 1 /* subtracted when forwarding */ 160 161 #define IP_MSS 576 /* default maximum segment size */ 162 163 /* in print-ip.c */ 164 extern u_int32_t ip_finddst(const struct ip *); 165