inet/netinet/ip6.h

   1 /* Copyright (C) 1991-2019 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    <http://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
  24 struct 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.  */
  50 struct 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.  */
  57 struct 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 */
  65 struct 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 */
  73 struct 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 */
  83 struct 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 */
  96 struct 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 */
 115 struct 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 */
 142 struct 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 */
 151 struct 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 */
 162 struct 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 */
 170 struct 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 */