/* * Copyright (c) 1982, 1986 Regents of the University of California. * All rights reserved. The Berkeley software License Agreement * specifies the terms and conditions for redistribution. * * @(#)ip.h 7.1 (Berkeley) 6/5/86 */ /* * Definitions for internet protocol version 4. * Per RFC 791, September 1981. */ #define IPVERSION 4 /* * Structure of an internet header, naked of options. * * We declare ip_len and ip_off to be short, rather than u_short * pragmatically since otherwise unsigned comparisons can result * against negative integers quite easily, and fail in subtle ways. */ struct ip { #ifdef vax u_char ip_hl:4, /* header length */ ip_v:4; /* version */ #endif u_char ip_tos; /* type of service */ short ip_len; /* total length */ u_short ip_id; /* identification */ short ip_off; /* fragment offset field */ #define IP_DF 0x4000 /* dont fragment flag */ #define IP_MF 0x2000 /* more fragments flag */ u_char ip_ttl; /* time to live */ u_char ip_p; /* protocol */ u_short ip_sum; /* checksum */ struct in_addr ip_src,ip_dst; /* source and dest address */ }; /* * Definitions for options. */ #define IPOPT_COPIED(o) ((o)&0x80) #define IPOPT_CLASS(o) ((o)&0x60) #define IPOPT_NUMBER(o) ((o)&0x1f) #define IPOPT_CONTROL 0x00 #define IPOPT_RESERVED1 0x20 #define IPOPT_DEBMEAS 0x40 #define IPOPT_RESERVED2 0x60 #define IPOPT_EOL 0 /* end of option list */ #define IPOPT_NOP 1 /* no operation */ #define IPOPT_RR 7 /* record packet route */ #define IPOPT_TS 68 /* timestamp */ #define IPOPT_SECURITY 130 /* provide s,c,h,tcc */ #define IPOPT_LSRR 131 /* loose source route */ #define IPOPT_SATID 136 /* satnet id */ #define IPOPT_SSRR 137 /* strict source route */ /* * Offsets to fields in options other than EOL and NOP. */ #define IPOPT_OPTVAL 0 /* option ID */ #define IPOPT_OLEN 1 /* option length */ #define IPOPT_OFFSET 2 /* offset within option */ #define IPOPT_MINOFF 4 /* min value of above */ /* * Time stamp option structure. */ struct ip_timestamp { u_char ipt_code; /* IPOPT_TS */ u_char ipt_len; /* size of structure (variable) */ u_char ipt_ptr; /* index of current entry */ u_char ipt_flg:4, /* flags, see below */ ipt_oflw:4; /* overflow counter */ union { n_long ipt_time[1]; struct ipt_ta { struct in_addr ipt_addr; n_long ipt_time; } ipt_ta[1]; } }; /* flag bits for ipt_flg */ #define IPOPT_TS_TSONLY 0 /* timestamps only */ #define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ #define IPOPT_TS_PRESPEC 2 /* specified modules only */ /* bits for security (not byte swapped) */ #define IPOPT_SECUR_UNCLASS 0x0000 #define IPOPT_SECUR_CONFID 0xf135 #define IPOPT_SECUR_EFTO 0x789a #define IPOPT_SECUR_MMMM 0xbc4d #define IPOPT_SECUR_RESTR 0xaf13 #define IPOPT_SECUR_SECRET 0xd788 #define IPOPT_SECUR_TOPSECRET 0x6bc5 /* * Internet implementation parameters. */ #define MAXTTL 255 /* maximum time to live (seconds) */ #define IPFRAGTTL 15 /* time to live for frag chains */ #define IPTTLDEC 1 /* subtracted when forwarding */ #define IP_MSS 576 /* default maximum segment size */