/* Copyright (C) 1991-1997, 2001, 2003, 2006 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#ifndef _NETINET_IP6_H
#define _NETINET_IP6_H 1

#include <inttypes.h>
#include <netinet/in.h>

struct ip6_hdr
  {
    union
      {
        struct ip6_hdrctl
          {
            uint32_t ip6_un1_flow;   /* 4 bits version, 8 bits TC,
                                        20 bits flow-ID */
            uint16_t ip6_un1_plen;   /* payload length */
            uint8_t  ip6_un1_nxt;    /* next header */
            uint8_t  ip6_un1_hlim;   /* hop limit */
          } ip6_un1;
        uint8_t ip6_un2_vfc;       /* 4 bits version, top 4 bits tclass */
      } ip6_ctlun;
    struct in6_addr ip6_src;      /* source address */
    struct in6_addr ip6_dst;      /* destination address */
  };

#define ip6_vfc   ip6_ctlun.ip6_un2_vfc
#define ip6_flow  ip6_ctlun.ip6_un1.ip6_un1_flow
#define ip6_plen  ip6_ctlun.ip6_un1.ip6_un1_plen
#define ip6_nxt   ip6_ctlun.ip6_un1.ip6_un1_nxt
#define ip6_hlim  ip6_ctlun.ip6_un1.ip6_un1_hlim
#define ip6_hops  ip6_ctlun.ip6_un1.ip6_un1_hlim

/* Generic extension header.  */
struct ip6_ext
  {
    uint8_t  ip6e_nxt;                /* next header.  */
    uint8_t  ip6e_len;                /* length in units of 8 octets.  */
  };

/* Hop-by-Hop options header.  */
struct ip6_hbh
  {
    uint8_t  ip6h_nxt;                /* next header.  */
    uint8_t  ip6h_len;                /* length in units of 8 octets.  */
    /* followed by options */
  };

/* Destination options header */
struct ip6_dest
  {
    uint8_t  ip6d_nxt;                /* next header */
    uint8_t  ip6d_len;                /* length in units of 8 octets */
    /* followed by options */
  };

/* Routing header */
struct ip6_rthdr
  {
    uint8_t  ip6r_nxt;                /* next header */
    uint8_t  ip6r_len;                /* length in units of 8 octets */
    uint8_t  ip6r_type;                /* routing type */
    uint8_t  ip6r_segleft;        /* segments left */
    /* followed by routing type specific data */
  };

/* Type 0 Routing header */
struct ip6_rthdr0
  {
    uint8_t  ip6r0_nxt;                /* next header */
    uint8_t  ip6r0_len;                /* length in units of 8 octets */
    uint8_t  ip6r0_type;        /* always zero */
    uint8_t  ip6r0_segleft;        /* segments left */
    uint8_t  ip6r0_reserved;        /* reserved field */
    uint8_t  ip6r0_slmap[3];        /* strict/loose bit map */
    /* followed by up to 127 struct in6_addr */
    struct in6_addr ip6r0_addr[0];
  };

/* Fragment header */
struct ip6_frag
  {
    uint8_t   ip6f_nxt;                /* next header */
    uint8_t   ip6f_reserved;        /* reserved field */
    uint16_t  ip6f_offlg;        /* offset, reserved, and flag */
    uint32_t  ip6f_ident;        /* identification */
  };

#if BYTE_ORDER == BIG_ENDIAN
# define IP6F_OFF_MASK       0xfff8  /* mask out offset from _offlg */
# define IP6F_RESERVED_MASK  0x0006  /* reserved bits in ip6f_offlg */
# define IP6F_MORE_FRAG      0x0001  /* more-fragments flag */
#else   /* BYTE_ORDER == LITTLE_ENDIAN */
# define IP6F_OFF_MASK       0xf8ff  /* mask out offset from _offlg */
# define IP6F_RESERVED_MASK  0x0600  /* reserved bits in ip6f_offlg */
# define IP6F_MORE_FRAG      0x0100  /* more-fragments flag */
#endif

/* IPv6 options */
struct ip6_opt
  {
    uint8_t  ip6o_type;
    uint8_t  ip6o_len;
  };

/* The high-order 3 bits of the option type define the behavior
 * when processing an unknown option and whether or not the option
 * content changes in flight.
 */
#define IP6OPT_TYPE(o)                ((o) & 0xc0)
#define IP6OPT_TYPE_SKIP        0x00
#define IP6OPT_TYPE_DISCARD        0x40
#define IP6OPT_TYPE_FORCEICMP        0x80
#define IP6OPT_TYPE_ICMP        0xc0
#define IP6OPT_TYPE_MUTABLE        0x20

/* Special option types for padding.  */
#define IP6OPT_PAD1        0
#define IP6OPT_PADN        1

#define IP6OPT_JUMBO                0xc2
#define IP6OPT_NSAP_ADDR        0xc3
#define IP6OPT_TUNNEL_LIMIT        0x04
#define IP6OPT_ROUTER_ALERT        0x05

/* Jumbo Payload Option */
struct ip6_opt_jumbo
  {
    uint8_t  ip6oj_type;
    uint8_t  ip6oj_len;
    uint8_t  ip6oj_jumbo_len[4];
  };
#define IP6OPT_JUMBO_LEN        6

/* NSAP Address Option */
struct ip6_opt_nsap
  {
    uint8_t  ip6on_type;
    uint8_t  ip6on_len;
    uint8_t  ip6on_src_nsap_len;
    uint8_t  ip6on_dst_nsap_len;
      /* followed by source NSAP */
      /* followed by destination NSAP */
  };

/* Tunnel Limit Option */
struct ip6_opt_tunnel
  {
    uint8_t  ip6ot_type;
    uint8_t  ip6ot_len;
    uint8_t  ip6ot_encap_limit;
  };

/* Router Alert Option */
struct ip6_opt_router
  {
    uint8_t  ip6or_type;
    uint8_t  ip6or_len;
    uint8_t  ip6or_value[2];
  };

/* Router alert values (in network byte order) */
#if BYTE_ORDER == BIG_ENDIAN
# define IP6_ALERT_MLD        0x0000
# define IP6_ALERT_RSVP        0x0001
# define IP6_ALERT_AN        0x0002
#else /* BYTE_ORDER == LITTLE_ENDING */
# define IP6_ALERT_MLD        0x0000
# define IP6_ALERT_RSVP        0x0100
# define IP6_ALERT_AN        0x0200
#endif

#endif /* netinet/ip6.h */