include/linux/ipv6.h

#ifndef _IPV6_H
#define _IPV6_H

#include <linux/in6.h>
#include <asm/byteorder.h>

/* The latest drafts declared increase in minimal mtu up to 1280. */

#define IPV6_MIN_MTU	1280

/*
 *	Advanced API
 *	source interface/address selection, source routing, etc...
 *	*under construction*
 */


struct in6_pktinfo {
	struct in6_addr	ipi6_addr;
	int		ipi6_ifindex;
};


struct in6_ifreq {
	struct in6_addr	ifr6_addr;
	__u32		ifr6_prefixlen;
	int		ifr6_ifindex; 
};

#define IPV6_SRCRT_STRICT	0x01	/* this hop must be a neighbor	*/
#define IPV6_SRCRT_TYPE_0	0	/* IPv6 type 0 Routing Header	*/

/*
 *	routing header
 */
struct ipv6_rt_hdr {
	__u8		nexthdr;
	__u8		hdrlen;
	__u8		type;
	__u8		segments_left;

	/*
	 *	type specific data
	 *	variable length field
	 */
};


struct ipv6_opt_hdr {
	__u8 		nexthdr;
	__u8 		hdrlen;
	/* 
	 * TLV encoded option data follows.
	 */
};

#define ipv6_destopt_hdr ipv6_opt_hdr
#define ipv6_hopopt_hdr  ipv6_opt_hdr

#ifdef __KERNEL__
#define ipv6_optlen(p)  (((p)->hdrlen+1) << 3)
#endif

/*
 *	routing header type 0 (used in cmsghdr struct)
 */

struct rt0_hdr {
	struct ipv6_rt_hdr	rt_hdr;
	__u32			bitmap;		/* strict/loose bit map */
	struct in6_addr		addr[0];

#define rt0_type		rt_hdr.type;
};

/*
 *	IPv6 fixed header
 *
 *	BEWARE, it is incorrect. The first 4 bits of flow_lbl
 *	are glued to priority now, forming "class".
 */

struct ipv6hdr {
#if defined(__LITTLE_ENDIAN_BITFIELD)
	__u8			priority:4,
				version:4;
#elif defined(__BIG_ENDIAN_BITFIELD)
	__u8			version:4,
				priority:4;
#else
#error	"Please fix <asm/byteorder.h>"
#endif
	__u8			flow_lbl[3];

	__u16			payload_len;
	__u8			nexthdr;
	__u8			hop_limit;

	struct	in6_addr	saddr;
	struct	in6_addr	daddr;
};

#ifdef __KERNEL__
#include <linux/in6.h>          /* struct sockaddr_in6 */
#include <linux/icmpv6.h>
#include <net/if_inet6.h>       /* struct ipv6_mc_socklist */
#include <linux/tcp.h>

/* 
   This structure contains results of exthdrs parsing
   as offsets from skb->nh.
 */

struct inet6_skb_parm
{
	int			iif;
	__u16			ra;
	__u16			hop;
	__u16			auth;
	__u16			dst0;
	__u16			srcrt;
	__u16			dst1;
};

struct ipv6_pinfo {
	struct in6_addr 	saddr;
	struct in6_addr 	rcv_saddr;
	struct in6_addr		daddr;
	struct in6_addr		*daddr_cache;

	__u32			flow_label;
	__u32			frag_size;
	int			hop_limit;
	int			mcast_hops;
	int			mcast_oif;

	/* pktoption flags */
	union {
		struct {
			__u8	srcrt:2,
			        rxinfo:1,
				rxhlim:1,
				hopopts:1,
				dstopts:1,
                                authhdr:1,
                                rxflow:1;
		} bits;
		__u8		all;
	} rxopt;

	/* sockopt flags */
	__u8			mc_loop:1,
	                        recverr:1,
	                        sndflow:1,
	                        pmtudisc:2;

	struct ipv6_mc_socklist	*ipv6_mc_list;
	struct ipv6_fl_socklist *ipv6_fl_list;
	__u32			dst_cookie;

	struct ipv6_txoptions	*opt;
	struct sk_buff		*pktoptions;
};

struct raw6_opt {
	__u32			checksum;	/* perform checksum */
	__u32			offset;		/* checksum offset  */

	struct icmp6_filter	filter;
};

/* WARNING: don't change the layout of the members in {raw,udp,tcp}6_sock! */
struct raw6_sock {
	struct sock	  sk;
	struct ipv6_pinfo *pinet6;
	struct inet_opt   inet;
	struct raw6_opt   raw6;
	struct ipv6_pinfo inet6;
};

struct udp6_sock {
	struct sock	  sk;
	struct ipv6_pinfo *pinet6;
	struct inet_opt   inet;
	struct ipv6_pinfo inet6;
};

struct tcp6_sock {
	struct sock	  sk;
	struct ipv6_pinfo *pinet6;
	struct inet_opt   inet;
	struct tcp_opt	  tcp;
	struct ipv6_pinfo inet6;
};

#define inet6_sk(__sk) ((struct raw6_sock *)__sk)->pinet6
#define raw6_sk(__sk) (&((struct raw6_sock *)__sk)->raw6)
#endif

#endif