1/* Copyright (C) 1991-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#ifndef _NETINET_IP6_H
19#define _NETINET_IP6_H 1
20
21#include <inttypes.h>
22#include <netinet/in.h>
23
24struct ip6_hdr
25 {
26 union
27 {
28 struct ip6_hdrctl
29 {
30 uint32_t ip6_un1_flow; /* 4 bits version, 8 bits TC,
31 20 bits flow-ID */
32 uint16_t ip6_un1_plen; /* payload length */
33 uint8_t ip6_un1_nxt; /* next header */
34 uint8_t ip6_un1_hlim; /* hop limit */
35 } ip6_un1;
36 uint8_t ip6_un2_vfc; /* 4 bits version, top 4 bits tclass */
37 } ip6_ctlun;
38 struct in6_addr ip6_src; /* source address */
39 struct in6_addr ip6_dst; /* destination address */
40 };
41
42#define ip6_vfc ip6_ctlun.ip6_un2_vfc
43#define ip6_flow ip6_ctlun.ip6_un1.ip6_un1_flow
44#define ip6_plen ip6_ctlun.ip6_un1.ip6_un1_plen
45#define ip6_nxt ip6_ctlun.ip6_un1.ip6_un1_nxt
46#define ip6_hlim ip6_ctlun.ip6_un1.ip6_un1_hlim
47#define ip6_hops ip6_ctlun.ip6_un1.ip6_un1_hlim
48
49/* Generic extension header. */
50struct ip6_ext
51 {
52 uint8_t ip6e_nxt; /* next header. */
53 uint8_t ip6e_len; /* length in units of 8 octets. */
54 };
55
56/* Hop-by-Hop options header. */
57struct ip6_hbh
58 {
59 uint8_t ip6h_nxt; /* next header. */
60 uint8_t ip6h_len; /* length in units of 8 octets. */
61 /* followed by options */
62 };
63
64/* Destination options header */
65struct ip6_dest
66 {
67 uint8_t ip6d_nxt; /* next header */
68 uint8_t ip6d_len; /* length in units of 8 octets */
69 /* followed by options */
70 };
71
72/* Routing header */
73struct ip6_rthdr
74 {
75 uint8_t ip6r_nxt; /* next header */
76 uint8_t ip6r_len; /* length in units of 8 octets */
77 uint8_t ip6r_type; /* routing type */
78 uint8_t ip6r_segleft; /* segments left */
79 /* followed by routing type specific data */
80 };
81
82/* Type 0 Routing header */
83struct ip6_rthdr0
84 {
85 uint8_t ip6r0_nxt; /* next header */
86 uint8_t ip6r0_len; /* length in units of 8 octets */
87 uint8_t ip6r0_type; /* always zero */
88 uint8_t ip6r0_segleft; /* segments left */
89 uint8_t ip6r0_reserved; /* reserved field */
90 uint8_t ip6r0_slmap[3]; /* strict/loose bit map */
91 /* followed by up to 127 struct in6_addr */
92 struct in6_addr ip6r0_addr[0];
93 };
94
95/* Fragment header */
96struct ip6_frag
97 {
98 uint8_t ip6f_nxt; /* next header */
99 uint8_t ip6f_reserved; /* reserved field */
100 uint16_t ip6f_offlg; /* offset, reserved, and flag */
101 uint32_t ip6f_ident; /* identification */
102 };
103
104#if __BYTE_ORDER == __BIG_ENDIAN
105# define IP6F_OFF_MASK 0xfff8 /* mask out offset from _offlg */
106# define IP6F_RESERVED_MASK 0x0006 /* reserved bits in ip6f_offlg */
107# define IP6F_MORE_FRAG 0x0001 /* more-fragments flag */
108#else /* __BYTE_ORDER == __LITTLE_ENDIAN */
109# define IP6F_OFF_MASK 0xf8ff /* mask out offset from _offlg */
110# define IP6F_RESERVED_MASK 0x0600 /* reserved bits in ip6f_offlg */
111# define IP6F_MORE_FRAG 0x0100 /* more-fragments flag */
112#endif
113
114/* IPv6 options */
115struct ip6_opt
116 {
117 uint8_t ip6o_type;
118 uint8_t ip6o_len;
119 };
120
121/* The high-order 3 bits of the option type define the behavior
122 * when processing an unknown option and whether or not the option
123 * content changes in flight.
124 */
125#define IP6OPT_TYPE(o) ((o) & 0xc0)
126#define IP6OPT_TYPE_SKIP 0x00
127#define IP6OPT_TYPE_DISCARD 0x40
128#define IP6OPT_TYPE_FORCEICMP 0x80
129#define IP6OPT_TYPE_ICMP 0xc0
130#define IP6OPT_TYPE_MUTABLE 0x20
131
132/* Special option types for padding. */
133#define IP6OPT_PAD1 0
134#define IP6OPT_PADN 1
135
136#define IP6OPT_JUMBO 0xc2
137#define IP6OPT_NSAP_ADDR 0xc3
138#define IP6OPT_TUNNEL_LIMIT 0x04
139#define IP6OPT_ROUTER_ALERT 0x05
140
141/* Jumbo Payload Option */
142struct ip6_opt_jumbo
143 {
144 uint8_t ip6oj_type;
145 uint8_t ip6oj_len;
146 uint8_t ip6oj_jumbo_len[4];
147 };
148#define IP6OPT_JUMBO_LEN 6
149
150/* NSAP Address Option */
151struct ip6_opt_nsap
152 {
153 uint8_t ip6on_type;
154 uint8_t ip6on_len;
155 uint8_t ip6on_src_nsap_len;
156 uint8_t ip6on_dst_nsap_len;
157 /* followed by source NSAP */
158 /* followed by destination NSAP */
159 };
160
161/* Tunnel Limit Option */
162struct ip6_opt_tunnel
163 {
164 uint8_t ip6ot_type;
165 uint8_t ip6ot_len;
166 uint8_t ip6ot_encap_limit;
167 };
168
169/* Router Alert Option */
170struct ip6_opt_router
171 {
172 uint8_t ip6or_type;
173 uint8_t ip6or_len;
174 uint8_t ip6or_value[2];
175 };
176
177/* Router alert values (in network byte order) */
178#if __BYTE_ORDER == __BIG_ENDIAN
179# define IP6_ALERT_MLD 0x0000
180# define IP6_ALERT_RSVP 0x0001
181# define IP6_ALERT_AN 0x0002
182#else /* __BYTE_ORDER == __LITTLE_ENDIAN */
183# define IP6_ALERT_MLD 0x0000
184# define IP6_ALERT_RSVP 0x0100
185# define IP6_ALERT_AN 0x0200
186#endif
187
188#endif /* netinet/ip6.h */
189