1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 * 17 * @(#)ip.h 7.7 (Berkeley) 06/29/88 18 */ 19 20 /* 21 * Definitions for internet protocol version 4. 22 * Per RFC 791, September 1981. 23 */ 24 #define IPVERSION 4 25 26 /* 27 * Structure of an internet header, naked of options. 28 * 29 * We declare ip_len and ip_off to be short, rather than u_short 30 * pragmatically since otherwise unsigned comparisons can result 31 * against negative integers quite easily, and fail in subtle ways. 32 */ 33 struct ip { 34 #if BYTE_ORDER == LITTLE_ENDIAN 35 u_char ip_hl:4, /* header length */ 36 ip_v:4; /* version */ 37 #endif 38 #if BYTE_ORDER == BIG_ENDIAN 39 u_char ip_v:4, /* version */ 40 ip_hl:4; /* header length */ 41 #endif 42 u_char ip_tos; /* type of service */ 43 short ip_len; /* total length */ 44 u_short ip_id; /* identification */ 45 short ip_off; /* fragment offset field */ 46 #define IP_DF 0x4000 /* dont fragment flag */ 47 #define IP_MF 0x2000 /* more fragments flag */ 48 u_char ip_ttl; /* time to live */ 49 u_char ip_p; /* protocol */ 50 u_short ip_sum; /* checksum */ 51 struct in_addr ip_src,ip_dst; /* source and dest address */ 52 }; 53 54 #define IP_MAXPACKET 65535 /* maximum packet size */ 55 56 /* 57 * Definitions for options. 58 */ 59 #define IPOPT_COPIED(o) ((o)&0x80) 60 #define IPOPT_CLASS(o) ((o)&0x60) 61 #define IPOPT_NUMBER(o) ((o)&0x1f) 62 63 #define IPOPT_CONTROL 0x00 64 #define IPOPT_RESERVED1 0x20 65 #define IPOPT_DEBMEAS 0x40 66 #define IPOPT_RESERVED2 0x60 67 68 #define IPOPT_EOL 0 /* end of option list */ 69 #define IPOPT_NOP 1 /* no operation */ 70 71 #define IPOPT_RR 7 /* record packet route */ 72 #define IPOPT_TS 68 /* timestamp */ 73 #define IPOPT_SECURITY 130 /* provide s,c,h,tcc */ 74 #define IPOPT_LSRR 131 /* loose source route */ 75 #define IPOPT_SATID 136 /* satnet id */ 76 #define IPOPT_SSRR 137 /* strict source route */ 77 78 /* 79 * Offsets to fields in options other than EOL and NOP. 80 */ 81 #define IPOPT_OPTVAL 0 /* option ID */ 82 #define IPOPT_OLEN 1 /* option length */ 83 #define IPOPT_OFFSET 2 /* offset within option */ 84 #define IPOPT_MINOFF 4 /* min value of above */ 85 86 /* 87 * Time stamp option structure. 88 */ 89 struct ip_timestamp { 90 u_char ipt_code; /* IPOPT_TS */ 91 u_char ipt_len; /* size of structure (variable) */ 92 u_char ipt_ptr; /* index of current entry */ 93 #if BYTE_ORDER == LITTLE_ENDIAN 94 u_char ipt_flg:4, /* flags, see below */ 95 ipt_oflw:4; /* overflow counter */ 96 #endif 97 #if BYTE_ORDER == BIG_ENDIAN 98 u_char ipt_oflw:4, /* overflow counter */ 99 ipt_flg:4; /* flags, see below */ 100 #endif 101 union ipt_timestamp { 102 n_long ipt_time[1]; 103 struct ipt_ta { 104 struct in_addr ipt_addr; 105 n_long ipt_time; 106 } ipt_ta[1]; 107 } ipt_timestamp; 108 }; 109 110 /* flag bits for ipt_flg */ 111 #define IPOPT_TS_TSONLY 0 /* timestamps only */ 112 #define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ 113 #define IPOPT_TS_PRESPEC 2 /* specified modules only */ 114 115 /* bits for security (not byte swapped) */ 116 #define IPOPT_SECUR_UNCLASS 0x0000 117 #define IPOPT_SECUR_CONFID 0xf135 118 #define IPOPT_SECUR_EFTO 0x789a 119 #define IPOPT_SECUR_MMMM 0xbc4d 120 #define IPOPT_SECUR_RESTR 0xaf13 121 #define IPOPT_SECUR_SECRET 0xd788 122 #define IPOPT_SECUR_TOPSECRET 0x6bc5 123 124 /* 125 * Internet implementation parameters. 126 */ 127 #define MAXTTL 255 /* maximum time to live (seconds) */ 128 #define IPFRAGTTL 60 /* time to live for frags, slowhz */ 129 #define IPTTLDEC 1 /* subtracted when forwarding */ 130 131 #define IP_MSS 576 /* default maximum segment size */ 132