1 /* 2 * Copyright (c) 1982, 1986, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)ip.h 8.2 (Berkeley) 06/01/94 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 #define IP_OFFMASK 0x1fff /* mask for fragmenting bits */ 39 u_char ip_ttl; /* time to live */ 40 u_char ip_p; /* protocol */ 41 u_short ip_sum; /* checksum */ 42 struct in_addr ip_src,ip_dst; /* source and dest address */ 43 }; 44 45 #define IP_MAXPACKET 65535 /* maximum packet size */ 46 47 /* 48 * Definitions for IP type of service (ip_tos) 49 */ 50 #define IPTOS_LOWDELAY 0x10 51 #define IPTOS_THROUGHPUT 0x08 52 #define IPTOS_RELIABILITY 0x04 53 54 /* 55 * Definitions for IP precedence (also in ip_tos) (hopefully unused) 56 */ 57 #define IPTOS_PREC_NETCONTROL 0xe0 58 #define IPTOS_PREC_INTERNETCONTROL 0xc0 59 #define IPTOS_PREC_CRITIC_ECP 0xa0 60 #define IPTOS_PREC_FLASHOVERRIDE 0x80 61 #define IPTOS_PREC_FLASH 0x60 62 #define IPTOS_PREC_IMMEDIATE 0x40 63 #define IPTOS_PREC_PRIORITY 0x20 64 #define IPTOS_PREC_ROUTINE 0x00 65 66 /* 67 * Definitions for options. 68 */ 69 #define IPOPT_COPIED(o) ((o)&0x80) 70 #define IPOPT_CLASS(o) ((o)&0x60) 71 #define IPOPT_NUMBER(o) ((o)&0x1f) 72 73 #define IPOPT_CONTROL 0x00 74 #define IPOPT_RESERVED1 0x20 75 #define IPOPT_DEBMEAS 0x40 76 #define IPOPT_RESERVED2 0x60 77 78 #define IPOPT_EOL 0 /* end of option list */ 79 #define IPOPT_NOP 1 /* no operation */ 80 81 #define IPOPT_RR 7 /* record packet route */ 82 #define IPOPT_TS 68 /* timestamp */ 83 #define IPOPT_SECURITY 130 /* provide s,c,h,tcc */ 84 #define IPOPT_LSRR 131 /* loose source route */ 85 #define IPOPT_SATID 136 /* satnet id */ 86 #define IPOPT_SSRR 137 /* strict source route */ 87 88 /* 89 * Offsets to fields in options other than EOL and NOP. 90 */ 91 #define IPOPT_OPTVAL 0 /* option ID */ 92 #define IPOPT_OLEN 1 /* option length */ 93 #define IPOPT_OFFSET 2 /* offset within option */ 94 #define IPOPT_MINOFF 4 /* min value of above */ 95 96 /* 97 * Time stamp option structure. 98 */ 99 struct ip_timestamp { 100 u_char ipt_code; /* IPOPT_TS */ 101 u_char ipt_len; /* size of structure (variable) */ 102 u_char ipt_ptr; /* index of current entry */ 103 #if BYTE_ORDER == LITTLE_ENDIAN 104 u_char ipt_flg:4, /* flags, see below */ 105 ipt_oflw:4; /* overflow counter */ 106 #endif 107 #if BYTE_ORDER == BIG_ENDIAN 108 u_char ipt_oflw:4, /* overflow counter */ 109 ipt_flg:4; /* flags, see below */ 110 #endif 111 union ipt_timestamp { 112 n_long ipt_time[1]; 113 struct ipt_ta { 114 struct in_addr ipt_addr; 115 n_long ipt_time; 116 } ipt_ta[1]; 117 } ipt_timestamp; 118 }; 119 120 /* flag bits for ipt_flg */ 121 #define IPOPT_TS_TSONLY 0 /* timestamps only */ 122 #define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ 123 #define IPOPT_TS_PRESPEC 3 /* specified modules only */ 124 125 /* bits for security (not byte swapped) */ 126 #define IPOPT_SECUR_UNCLASS 0x0000 127 #define IPOPT_SECUR_CONFID 0xf135 128 #define IPOPT_SECUR_EFTO 0x789a 129 #define IPOPT_SECUR_MMMM 0xbc4d 130 #define IPOPT_SECUR_RESTR 0xaf13 131 #define IPOPT_SECUR_SECRET 0xd788 132 #define IPOPT_SECUR_TOPSECRET 0x6bc5 133 134 /* 135 * Internet implementation parameters. 136 */ 137 #define MAXTTL 255 /* maximum time to live (seconds) */ 138 #define IPDEFTTL 64 /* default ttl, from RFC 1340 */ 139 #define IPFRAGTTL 60 /* time to live for frags, slowhz */ 140 #define IPTTLDEC 1 /* subtracted when forwarding */ 141 142 #define IP_MSS 576 /* default maximum segment size */ 143