1/* @(#) Header: /tcpdump/master/tcpdump/ip.h,v 1.12 2007-09-14 01:29:28 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. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * @(#)ip.h 8.2 (Berkeley) 6/1/94 31 */ 32 33/* 34 * Definitions for internet protocol version 4. 35 * Per RFC 791, September 1981. 36 */ 37#define IPVERSION 4 38 39/* 40 * Structure of an internet header, naked of options. 41 * 42 * We declare ip_len and ip_off to be short, rather than u_short 43 * pragmatically since otherwise unsigned comparisons can result 44 * against negative integers quite easily, and fail in subtle ways. 45 */ 46struct ip { 47 u_int8_t ip_vhl; /* header length, version */ 48#define IP_V(ip) (((ip)->ip_vhl & 0xf0) >> 4) 49#define IP_HL(ip) ((ip)->ip_vhl & 0x0f) 50 u_int8_t ip_tos; /* type of service */ 51 u_int16_t ip_len; /* total length */ 52 u_int16_t ip_id; /* identification */ 53 u_int16_t ip_off; /* fragment offset field */ 54#define IP_DF 0x4000 /* dont fragment flag */ 55#define IP_MF 0x2000 /* more fragments flag */ 56#define IP_OFFMASK 0x1fff /* mask for fragmenting bits */ 57 u_int8_t ip_ttl; /* time to live */ 58 u_int8_t ip_p; /* protocol */ 59 u_int16_t ip_sum; /* checksum */ 60 struct in_addr ip_src,ip_dst; /* source and dest address */ 61}; 62 63#define IP_MAXPACKET 65535 /* maximum packet size */ 64 65/* 66 * Definitions for IP type of service (ip_tos) 67 */ 68#define IPTOS_LOWDELAY 0x10 69#define IPTOS_THROUGHPUT 0x08 70#define IPTOS_RELIABILITY 0x04 71 72/* 73 * Definitions for IP precedence (also in ip_tos) (hopefully unused) 74 */ 75#define IPTOS_PREC_NETCONTROL 0xe0 76#define IPTOS_PREC_INTERNETCONTROL 0xc0 77#define IPTOS_PREC_CRITIC_ECP 0xa0 78#define IPTOS_PREC_FLASHOVERRIDE 0x80 79#define IPTOS_PREC_FLASH 0x60 80#define IPTOS_PREC_IMMEDIATE 0x40 81#define IPTOS_PREC_PRIORITY 0x20 82#define IPTOS_PREC_ROUTINE 0x00 83 84/* 85 * Definitions for options. 86 */ 87#define IPOPT_COPIED(o) ((o)&0x80) 88#define IPOPT_CLASS(o) ((o)&0x60) 89#define IPOPT_NUMBER(o) ((o)&0x1f) 90 91#define IPOPT_CONTROL 0x00 92#define IPOPT_RESERVED1 0x20 93#define IPOPT_DEBMEAS 0x40 94#define IPOPT_RESERVED2 0x60 95 96#define IPOPT_EOL 0 /* end of option list */ 97#define IPOPT_NOP 1 /* no operation */ 98 99#define IPOPT_RR 7 /* record packet route */ 100#define IPOPT_TS 68 /* timestamp */ 101#define IPOPT_RFC1393 82 /* traceroute RFC 1393 */ 102#define IPOPT_SECURITY 130 /* provide s,c,h,tcc */ 103#define IPOPT_LSRR 131 /* loose source route */ 104#define IPOPT_SATID 136 /* satnet id */ 105#define IPOPT_SSRR 137 /* strict source route */ 106#define IPOPT_RA 148 /* router-alert, rfc2113 */ 107 108/* 109 * Offsets to fields in options other than EOL and NOP. 110 */ 111#define IPOPT_OPTVAL 0 /* option ID */ 112#define IPOPT_OLEN 1 /* option length */ 113#define IPOPT_OFFSET 2 /* offset within option */ 114#define IPOPT_MINOFF 4 /* min value of above */ 115 116/* 117 * Time stamp option structure. 118 */ 119struct ip_timestamp { 120 u_int8_t ipt_code; /* IPOPT_TS */ 121 u_int8_t ipt_len; /* size of structure (variable) */ 122 u_int8_t ipt_ptr; /* index of current entry */ 123 u_int8_t ipt_oflwflg; /* flags, overflow counter */ 124#define IPTS_OFLW(ip) (((ipt)->ipt_oflwflg & 0xf0) >> 4) 125#define IPTS_FLG(ip) ((ipt)->ipt_oflwflg & 0x0f) 126 union ipt_timestamp { 127 u_int32_t ipt_time[1]; 128 struct ipt_ta { 129 struct in_addr ipt_addr; 130 u_int32_t ipt_time; 131 } ipt_ta[1]; 132 } ipt_timestamp; 133}; 134 135/* flag bits for ipt_flg */ 136#define IPOPT_TS_TSONLY 0 /* timestamps only */ 137#define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ 138#define IPOPT_TS_PRESPEC 3 /* specified modules only */ 139 140/* bits for security (not byte swapped) */ 141#define IPOPT_SECUR_UNCLASS 0x0000 142#define IPOPT_SECUR_CONFID 0xf135 143#define IPOPT_SECUR_EFTO 0x789a 144#define IPOPT_SECUR_MMMM 0xbc4d 145#define IPOPT_SECUR_RESTR 0xaf13 146#define IPOPT_SECUR_SECRET 0xd788 147#define IPOPT_SECUR_TOPSECRET 0x6bc5 148 149/* 150 * Internet implementation parameters. 151 */ 152#define MAXTTL 255 /* maximum time to live (seconds) */ 153#define IPDEFTTL 64 /* default ttl, from RFC 1340 */ 154#define IPFRAGTTL 60 /* time to live for frags, slowhz */ 155#define IPTTLDEC 1 /* subtracted when forwarding */ 156 157#define IP_MSS 576 /* default maximum segment size */ 158 159/* in print-ip.c */ 160extern u_int32_t ip_finddst(const struct ip *); 161