1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)ip.h 7.10 (Berkeley) 06/28/90 8 */ 9 10 /* 11 * Definitions for internet protocol version 4. 12 * Per RFC 791, September 1981. 13 */ 14 #define IPVERSION 4 15 16 /* 17 * Structure of an internet header, naked of options. 18 * 19 * We declare ip_len and ip_off to be short, rather than u_short 20 * pragmatically since otherwise unsigned comparisons can result 21 * against negative integers quite easily, and fail in subtle ways. 22 */ 23 struct ip { 24 #if BYTE_ORDER == LITTLE_ENDIAN 25 u_char ip_hl:4, /* header length */ 26 ip_v:4; /* version */ 27 #endif 28 #if BYTE_ORDER == BIG_ENDIAN 29 u_char ip_v:4, /* version */ 30 ip_hl:4; /* header length */ 31 #endif 32 u_char ip_tos; /* type of service */ 33 short ip_len; /* total length */ 34 u_short ip_id; /* identification */ 35 short ip_off; /* fragment offset field */ 36 #define IP_DF 0x4000 /* dont fragment flag */ 37 #define IP_MF 0x2000 /* more fragments flag */ 38 u_char ip_ttl; /* time to live */ 39 u_char ip_p; /* protocol */ 40 u_short ip_sum; /* checksum */ 41 struct in_addr ip_src,ip_dst; /* source and dest address */ 42 }; 43 44 #define IP_MAXPACKET 65535 /* maximum packet size */ 45 46 /* 47 * Definitions for IP type of service (ip_tos) 48 */ 49 #define IPTOS_LOWDELAY 0x10 50 #define IPTOS_THROUGHPUT 0x08 51 #define IPTOS_RELIABILITY 0x04 52 53 /* 54 * Definitions for IP precedence (also in ip_tos) (hopefully unused) 55 */ 56 #define IPTOS_PREC_NETCONTROL 0xe0 57 #define IPTOS_PREC_INTERNETCONTROL 0xc0 58 #define IPTOS_PREC_CRITIC_ECP 0xa0 59 #define IPTOS_PREC_FLASHOVERRIDE 0x80 60 #define IPTOS_PREC_FLASH 0x60 61 #define IPTOS_PREC_IMMEDIATE 0x40 62 #define IPTOS_PREC_PRIORITY 0x20 63 #define IPTOS_PREC_ROUTINE 0x10 64 65 /* 66 * Definitions for options. 67 */ 68 #define IPOPT_COPIED(o) ((o)&0x80) 69 #define IPOPT_CLASS(o) ((o)&0x60) 70 #define IPOPT_NUMBER(o) ((o)&0x1f) 71 72 #define IPOPT_CONTROL 0x00 73 #define IPOPT_RESERVED1 0x20 74 #define IPOPT_DEBMEAS 0x40 75 #define IPOPT_RESERVED2 0x60 76 77 #define IPOPT_EOL 0 /* end of option list */ 78 #define IPOPT_NOP 1 /* no operation */ 79 80 #define IPOPT_RR 7 /* record packet route */ 81 #define IPOPT_TS 68 /* timestamp */ 82 #define IPOPT_SECURITY 130 /* provide s,c,h,tcc */ 83 #define IPOPT_LSRR 131 /* loose source route */ 84 #define IPOPT_SATID 136 /* satnet id */ 85 #define IPOPT_SSRR 137 /* strict source route */ 86 87 /* 88 * Offsets to fields in options other than EOL and NOP. 89 */ 90 #define IPOPT_OPTVAL 0 /* option ID */ 91 #define IPOPT_OLEN 1 /* option length */ 92 #define IPOPT_OFFSET 2 /* offset within option */ 93 #define IPOPT_MINOFF 4 /* min value of above */ 94 95 /* 96 * Time stamp option structure. 97 */ 98 struct ip_timestamp { 99 u_char ipt_code; /* IPOPT_TS */ 100 u_char ipt_len; /* size of structure (variable) */ 101 u_char ipt_ptr; /* index of current entry */ 102 #if BYTE_ORDER == LITTLE_ENDIAN 103 u_char ipt_flg:4, /* flags, see below */ 104 ipt_oflw:4; /* overflow counter */ 105 #endif 106 #if BYTE_ORDER == BIG_ENDIAN 107 u_char ipt_oflw:4, /* overflow counter */ 108 ipt_flg:4; /* flags, see below */ 109 #endif 110 union ipt_timestamp { 111 n_long ipt_time[1]; 112 struct ipt_ta { 113 struct in_addr ipt_addr; 114 n_long ipt_time; 115 } ipt_ta[1]; 116 } ipt_timestamp; 117 }; 118 119 /* flag bits for ipt_flg */ 120 #define IPOPT_TS_TSONLY 0 /* timestamps only */ 121 #define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ 122 #define IPOPT_TS_PRESPEC 3 /* specified modules only */ 123 124 /* bits for security (not byte swapped) */ 125 #define IPOPT_SECUR_UNCLASS 0x0000 126 #define IPOPT_SECUR_CONFID 0xf135 127 #define IPOPT_SECUR_EFTO 0x789a 128 #define IPOPT_SECUR_MMMM 0xbc4d 129 #define IPOPT_SECUR_RESTR 0xaf13 130 #define IPOPT_SECUR_SECRET 0xd788 131 #define IPOPT_SECUR_TOPSECRET 0x6bc5 132 133 /* 134 * Internet implementation parameters. 135 */ 136 #define MAXTTL 255 /* maximum time to live (seconds) */ 137 #define IPFRAGTTL 60 /* time to live for frags, slowhz */ 138 #define IPTTLDEC 1 /* subtracted when forwarding */ 139 140 #define IP_MSS 576 /* default maximum segment size */ 141