1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 * 6 * @(#)ip.h 7.1 (Berkeley) 06/05/86 7 */ 8 9 /* 10 * Definitions for internet protocol version 4. 11 * Per RFC 791, September 1981. 12 */ 13 #define IPVERSION 4 14 15 /* 16 * Structure of an internet header, naked of options. 17 * 18 * We declare ip_len and ip_off to be short, rather than u_short 19 * pragmatically since otherwise unsigned comparisons can result 20 * against negative integers quite easily, and fail in subtle ways. 21 */ 22 struct ip { 23 #ifdef vax 24 u_char ip_hl:4, /* header length */ 25 ip_v:4; /* version */ 26 #endif 27 u_char ip_tos; /* type of service */ 28 short ip_len; /* total length */ 29 u_short ip_id; /* identification */ 30 short ip_off; /* fragment offset field */ 31 #define IP_DF 0x4000 /* dont fragment flag */ 32 #define IP_MF 0x2000 /* more fragments flag */ 33 u_char ip_ttl; /* time to live */ 34 u_char ip_p; /* protocol */ 35 u_short ip_sum; /* checksum */ 36 struct in_addr ip_src,ip_dst; /* source and dest address */ 37 }; 38 39 /* 40 * Definitions for options. 41 */ 42 #define IPOPT_COPIED(o) ((o)&0x80) 43 #define IPOPT_CLASS(o) ((o)&0x60) 44 #define IPOPT_NUMBER(o) ((o)&0x1f) 45 46 #define IPOPT_CONTROL 0x00 47 #define IPOPT_RESERVED1 0x20 48 #define IPOPT_DEBMEAS 0x40 49 #define IPOPT_RESERVED2 0x60 50 51 #define IPOPT_EOL 0 /* end of option list */ 52 #define IPOPT_NOP 1 /* no operation */ 53 54 #define IPOPT_RR 7 /* record packet route */ 55 #define IPOPT_TS 68 /* timestamp */ 56 #define IPOPT_SECURITY 130 /* provide s,c,h,tcc */ 57 #define IPOPT_LSRR 131 /* loose source route */ 58 #define IPOPT_SATID 136 /* satnet id */ 59 #define IPOPT_SSRR 137 /* strict source route */ 60 61 /* 62 * Offsets to fields in options other than EOL and NOP. 63 */ 64 #define IPOPT_OPTVAL 0 /* option ID */ 65 #define IPOPT_OLEN 1 /* option length */ 66 #define IPOPT_OFFSET 2 /* offset within option */ 67 #define IPOPT_MINOFF 4 /* min value of above */ 68 69 /* 70 * Time stamp option structure. 71 */ 72 struct ip_timestamp { 73 u_char ipt_code; /* IPOPT_TS */ 74 u_char ipt_len; /* size of structure (variable) */ 75 u_char ipt_ptr; /* index of current entry */ 76 u_char ipt_flg:4, /* flags, see below */ 77 ipt_oflw:4; /* overflow counter */ 78 union { 79 n_long ipt_time[1]; 80 struct ipt_ta { 81 struct in_addr ipt_addr; 82 n_long ipt_time; 83 } ipt_ta[1]; 84 } 85 }; 86 87 /* flag bits for ipt_flg */ 88 #define IPOPT_TS_TSONLY 0 /* timestamps only */ 89 #define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ 90 #define IPOPT_TS_PRESPEC 2 /* specified modules only */ 91 92 /* bits for security (not byte swapped) */ 93 #define IPOPT_SECUR_UNCLASS 0x0000 94 #define IPOPT_SECUR_CONFID 0xf135 95 #define IPOPT_SECUR_EFTO 0x789a 96 #define IPOPT_SECUR_MMMM 0xbc4d 97 #define IPOPT_SECUR_RESTR 0xaf13 98 #define IPOPT_SECUR_SECRET 0xd788 99 #define IPOPT_SECUR_TOPSECRET 0x6bc5 100 101 /* 102 * Internet implementation parameters. 103 */ 104 #define MAXTTL 255 /* maximum time to live (seconds) */ 105 #define IPFRAGTTL 15 /* time to live for frag chains */ 106 #define IPTTLDEC 1 /* subtracted when forwarding */ 107 108 #define IP_MSS 576 /* default maximum segment size */ 109