1 /* 2 * Copyright (c) 1982 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 6.5 (Berkeley) 06/08/85 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 * Time stamp option structure. 63 */ 64 struct ip_timestamp { 65 u_char ipt_code; /* IPOPT_TS */ 66 u_char ipt_len; /* size of structure (variable) */ 67 u_char ipt_ptr; /* index of current entry */ 68 u_char ipt_flg:4, /* flags, see below */ 69 ipt_oflw:4; /* overflow counter */ 70 union { 71 n_long ipt_time[1]; 72 struct ipt_ta { 73 struct in_addr ipt_addr; 74 n_long ipt_time; 75 } ipt_ta[1]; 76 } 77 }; 78 79 /* flag bits for ipt_flg */ 80 #define IPOPT_TS_TSONLY 0 /* timestamps only */ 81 #define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ 82 #define IPOPT_TS_PRESPEC 2 /* specified modules only */ 83 84 /* bits for security (not byte swapped) */ 85 #define IPOPT_SECUR_UNCLASS 0x0000 86 #define IPOPT_SECUR_CONFID 0xf135 87 #define IPOPT_SECUR_EFTO 0x789a 88 #define IPOPT_SECUR_MMMM 0xbc4d 89 #define IPOPT_SECUR_RESTR 0xaf13 90 #define IPOPT_SECUR_SECRET 0xd788 91 #define IPOPT_SECUR_TOPSECRET 0x6bc5 92 93 /* 94 * Internet implementation parameters. 95 */ 96 #define MAXTTL 255 /* maximum time to live (seconds) */ 97 #define IPFRAGTTL 15 /* time to live for frag chains */ 98 #define IPTTLDEC 1 /* subtracted when forwarding */ 99 100 #define IP_MSS 576 /* default maximum segment size */ 101