ip.h revision 127668
1/* @(#) $Header: /tcpdump/master/tcpdump/ip.h,v 1.10 2002/12/11 07:13:53 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 */ 50struct 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_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 */ 109 110/* 111 * Offsets to fields in options other than EOL and NOP. 112 */ 113#define IPOPT_OPTVAL 0 /* option ID */ 114#define IPOPT_OLEN 1 /* option length */ 115#define IPOPT_OFFSET 2 /* offset within option */ 116#define IPOPT_MINOFF 4 /* min value of above */ 117 118/* 119 * Time stamp option structure. 120 */ 121struct ip_timestamp { 122 u_int8_t ipt_code; /* IPOPT_TS */ 123 u_int8_t ipt_len; /* size of structure (variable) */ 124 u_int8_t ipt_ptr; /* index of current entry */ 125 u_int8_t ipt_oflwflg; /* flags, overflow counter */ 126#define IPTS_OFLW(ip) (((ipt)->ipt_oflwflg & 0xf0) >> 4) 127#define IPTS_FLG(ip) ((ipt)->ipt_oflwflg & 0x0f) 128 union ipt_timestamp { 129 u_int32_t ipt_time[1]; 130 struct ipt_ta { 131 struct in_addr ipt_addr; 132 u_int32_t ipt_time; 133 } ipt_ta[1]; 134 } ipt_timestamp; 135}; 136 137/* flag bits for ipt_flg */ 138#define IPOPT_TS_TSONLY 0 /* timestamps only */ 139#define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ 140#define IPOPT_TS_PRESPEC 3 /* specified modules only */ 141 142/* bits for security (not byte swapped) */ 143#define IPOPT_SECUR_UNCLASS 0x0000 144#define IPOPT_SECUR_CONFID 0xf135 145#define IPOPT_SECUR_EFTO 0x789a 146#define IPOPT_SECUR_MMMM 0xbc4d 147#define IPOPT_SECUR_RESTR 0xaf13 148#define IPOPT_SECUR_SECRET 0xd788 149#define IPOPT_SECUR_TOPSECRET 0x6bc5 150 151/* 152 * Internet implementation parameters. 153 */ 154#define MAXTTL 255 /* maximum time to live (seconds) */ 155#define IPDEFTTL 64 /* default ttl, from RFC 1340 */ 156#define IPFRAGTTL 60 /* time to live for frags, slowhz */ 157#define IPTTLDEC 1 /* subtracted when forwarding */ 158 159#define IP_MSS 576 /* default maximum segment size */ 160 161/* in print-ip.c */ 162extern u_int32_t ip_finddst(const struct ip *); 163