1 /* ip.h 6.4 84/10/19 */ 2 3 /* 4 * Definitions for internet protocol version 4. 5 * Per RFC 791, September 1981. 6 */ 7 #define IPVERSION 4 8 9 /* 10 * Structure of an internet header, naked of options. 11 * 12 * We declare ip_len and ip_off to be short, rather than u_short 13 * pragmatically since otherwise unsigned comparisons can result 14 * against negative integers quite easily, and fail in subtle ways. 15 */ 16 struct ip { 17 #ifdef vax 18 u_char ip_hl:4, /* header length */ 19 ip_v:4; /* version */ 20 #endif 21 u_char ip_tos; /* type of service */ 22 short ip_len; /* total length */ 23 u_short ip_id; /* identification */ 24 short ip_off; /* fragment offset field */ 25 #define IP_DF 0x4000 /* dont fragment flag */ 26 #define IP_MF 0x2000 /* more fragments flag */ 27 u_char ip_ttl; /* time to live */ 28 u_char ip_p; /* protocol */ 29 u_short ip_sum; /* checksum */ 30 struct in_addr ip_src,ip_dst; /* source and dest address */ 31 }; 32 33 /* 34 * Definitions for options. 35 */ 36 #define IPOPT_COPIED(o) ((o)&0x80) 37 #define IPOPT_CLASS(o) ((o)&0x60) 38 #define IPOPT_NUMBER(o) ((o)&0x1f) 39 40 #define IPOPT_CONTROL 0x00 41 #define IPOPT_RESERVED1 0x20 42 #define IPOPT_DEBMEAS 0x40 43 #define IPOPT_RESERVED2 0x60 44 45 #define IPOPT_EOL 0 /* end of option list */ 46 #define IPOPT_NOP 1 /* no operation */ 47 48 #define IPOPT_RR 7 /* record packet route */ 49 #define IPOPT_TS 68 /* timestamp */ 50 #define IPOPT_SECURITY 130 /* provide s,c,h,tcc */ 51 #define IPOPT_LSRR 131 /* loose source route */ 52 #define IPOPT_SATID 136 /* satnet id */ 53 #define IPOPT_SSRR 137 /* strict source route */ 54 55 /* 56 * Time stamp option structure. 57 */ 58 struct ip_timestamp { 59 u_char ipt_code; /* IPOPT_TS */ 60 u_char ipt_len; /* size of structure (variable) */ 61 u_char ipt_ptr; /* index of current entry */ 62 u_char ipt_flg:4, /* flags, see below */ 63 ipt_oflw:4; /* overflow counter */ 64 union { 65 n_long ipt_time[1]; 66 struct ipt_ta { 67 struct in_addr ipt_addr; 68 n_long ipt_time; 69 } ipt_ta[1]; 70 } 71 }; 72 73 /* flag bits for ipt_flg */ 74 #define IPOPT_TS_TSONLY 0 /* timestamps only */ 75 #define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */ 76 #define IPOPT_TS_PRESPEC 2 /* specified modules only */ 77 78 /* bits for security (not byte swapped) */ 79 #define IPOPT_SECUR_UNCLASS 0x0000 80 #define IPOPT_SECUR_CONFID 0xf135 81 #define IPOPT_SECUR_EFTO 0x789a 82 #define IPOPT_SECUR_MMMM 0xbc4d 83 #define IPOPT_SECUR_RESTR 0xaf13 84 #define IPOPT_SECUR_SECRET 0xd788 85 #define IPOPT_SECUR_TOPSECRET 0x6bc5 86 87 /* 88 * Internet implementation parameters. 89 */ 90 #define MAXTTL 255 /* maximum time to live (seconds) */ 91 #define IPFRAGTTL 15 /* time to live for frag chains */ 92 #define IPTTLDEC 1 /* subtracted when forwarding */ 93 94 #define IP_MSS 576 /* default maximum segment size */ 95