1 /* $NetBSD: ip.h,v 1.9 1995/05/15 01:22:44 cgd Exp $ */
4 * Copyright (c) 1982, 1986, 1993
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35 * @(#)ip.h 8.1 (Berkeley) 6/10/93
39 * Definitions for internet protocol version 4.
40 * Per RFC 791, September 1981.
45 * Structure of an internet header, naked of options.
47 * We declare ip_len and ip_off to be short, rather than u_short
48 * pragmatically since otherwise unsigned comparisons can result
49 * against negative integers quite easily, and fail in subtle ways.
52 #if BYTE_ORDER == LITTLE_ENDIAN
53 u_int8_t ip_hl:4, /* header length */
56 #if BYTE_ORDER == BIG_ENDIAN
57 u_int8_t ip_v:4, /* version */
58 ip_hl:4; /* header length */
60 u_int8_t ip_tos; /* type of service */
61 int16_t ip_len; /* total length */
62 u_int16_t ip_id; /* identification */
63 int16_t ip_off; /* fragment offset field */
64 #define IP_DF 0x4000 /* dont fragment flag */
65 #define IP_MF 0x2000 /* more fragments flag */
66 #define IP_OFFMASK 0x1fff /* mask for fragmenting bits */
67 u_int8_t ip_ttl; /* time to live */
68 u_int8_t ip_p; /* protocol */
69 u_int16_t ip_sum; /* checksum */
70 struct in_addr ip_src, ip_dst; /* source and dest address */
73 #define IP_MAXPACKET 65535 /* maximum packet size */
76 * Definitions for IP type of service (ip_tos)
78 #define IPTOS_LOWDELAY 0x10
79 #define IPTOS_THROUGHPUT 0x08
80 #define IPTOS_RELIABILITY 0x04
81 /* IPTOS_LOWCOST 0x02 XXX */
84 * Definitions for IP precedence (also in ip_tos) (hopefully unused)
86 #define IPTOS_PREC_NETCONTROL 0xe0
87 #define IPTOS_PREC_INTERNETCONTROL 0xc0
88 #define IPTOS_PREC_CRITIC_ECP 0xa0
89 #define IPTOS_PREC_FLASHOVERRIDE 0x80
90 #define IPTOS_PREC_FLASH 0x60
91 #define IPTOS_PREC_IMMEDIATE 0x40
92 #define IPTOS_PREC_PRIORITY 0x20
93 #define IPTOS_PREC_ROUTINE 0x00
96 * Definitions for options.
98 #define IPOPT_COPIED(o) ((o)&0x80)
99 #define IPOPT_CLASS(o) ((o)&0x60)
100 #define IPOPT_NUMBER(o) ((o)&0x1f)
102 #define IPOPT_CONTROL 0x00
103 #define IPOPT_RESERVED1 0x20
104 #define IPOPT_DEBMEAS 0x40
105 #define IPOPT_RESERVED2 0x60
107 #define IPOPT_EOL 0 /* end of option list */
108 #define IPOPT_NOP 1 /* no operation */
110 #define IPOPT_RR 7 /* record packet route */
111 #define IPOPT_TS 68 /* timestamp */
112 #define IPOPT_SECURITY 130 /* provide s,c,h,tcc */
113 #define IPOPT_LSRR 131 /* loose source route */
114 #define IPOPT_SATID 136 /* satnet id */
115 #define IPOPT_SSRR 137 /* strict source route */
118 * Offsets to fields in options other than EOL and NOP.
120 #define IPOPT_OPTVAL 0 /* option ID */
121 #define IPOPT_OLEN 1 /* option length */
122 #define IPOPT_OFFSET 2 /* offset within option */
123 #define IPOPT_MINOFF 4 /* min value of above */
126 * Time stamp option structure.
128 struct ip_timestamp {
129 u_int8_t ipt_code; /* IPOPT_TS */
130 u_int8_t ipt_len; /* size of structure (variable) */
131 u_int8_t ipt_ptr; /* index of current entry */
132 #if BYTE_ORDER == LITTLE_ENDIAN
133 u_int8_t ipt_flg:4, /* flags, see below */
134 ipt_oflw:4; /* overflow counter */
136 #if BYTE_ORDER == BIG_ENDIAN
137 u_int8_t ipt_oflw:4, /* overflow counter */
138 ipt_flg:4; /* flags, see below */
140 union ipt_timestamp {
141 u_int32_t ipt_time[1];
143 struct in_addr ipt_addr;
149 /* flag bits for ipt_flg */
150 #define IPOPT_TS_TSONLY 0 /* timestamps only */
151 #define IPOPT_TS_TSANDADDR 1 /* timestamps and addresses */
152 #define IPOPT_TS_PRESPEC 3 /* specified modules only */
154 /* bits for security (not byte swapped) */
155 #define IPOPT_SECUR_UNCLASS 0x0000
156 #define IPOPT_SECUR_CONFID 0xf135
157 #define IPOPT_SECUR_EFTO 0x789a
158 #define IPOPT_SECUR_MMMM 0xbc4d
159 #define IPOPT_SECUR_RESTR 0xaf13
160 #define IPOPT_SECUR_SECRET 0xd788
161 #define IPOPT_SECUR_TOPSECRET 0x6bc5
164 * Internet implementation parameters.
166 #define MAXTTL 255 /* maximum time to live (seconds) */
167 #define IPDEFTTL 64 /* default ttl, from RFC 1340 */
168 #define IPFRAGTTL 60 /* time to live for frags, slowhz */
169 #define IPTTLDEC 1 /* subtracted when forwarding */
171 #define IP_MSS 576 /* default maximum segment size */