/*
   *	Linux INET6 implementation
   *
   *	Authors:
   *	Pedro Roque		<roque@di.fc.ul.pt>
   *

   *	This program is free software; you can redistribute it and/or
   *      modify it under the terms of the GNU General Public License
   *      as published by the Free Software Foundation; either version
   *      2 of the License, or (at your option) any later version.
   */
  
  #ifndef _NET_IPV6_H
  #define _NET_IPV6_H
  
  #include <linux/ipv6.h>
  #include <linux/hardirq.h>

  #include <linux/jhash.h>

  #include <linux/refcount.h>

  #include <net/if_inet6.h>

  #include <net/ndisc.h>
  #include <net/flow.h>

  #include <net/flow_dissector.h>

  #include <net/snmp.h>
  
  #define SIN6_LEN_RFC2133	24
  
  #define IPV6_MAXPLEN		65535
  
  /*
   *	NextHeader field of IPv6 header
   */
  
  #define NEXTHDR_HOP		0	/* Hop-by-hop option header. */
  #define NEXTHDR_TCP		6	/* TCP segment. */
  #define NEXTHDR_UDP		17	/* UDP message. */
  #define NEXTHDR_IPV6		41	/* IPv6 in IPv6 */
  #define NEXTHDR_ROUTING		43	/* Routing header. */
  #define NEXTHDR_FRAGMENT	44	/* Fragmentation/reassembly header. */

  #define NEXTHDR_GRE		47	/* GRE header. */

  #define NEXTHDR_ESP		50	/* Encapsulating security payload. */
  #define NEXTHDR_AUTH		51	/* Authentication header. */
  #define NEXTHDR_ICMP		58	/* ICMP for IPv6. */
  #define NEXTHDR_NONE		59	/* No next header */
  #define NEXTHDR_DEST		60	/* Destination options header. */

  #define NEXTHDR_SCTP		132	/* SCTP message. */

  #define NEXTHDR_MOBILITY	135	/* Mobility header. */

  
  #define NEXTHDR_MAX		255

  #define IPV6_DEFAULT_HOPLIMIT   64
  #define IPV6_DEFAULT_MCASTHOPS	1
  
  /*
   *	Addr type
   *	
   *	type	-	unicast | multicast
   *	scope	-	local	| site	    | global
   *	v4	-	compat
   *	v4mapped
   *	any
   *	loopback
   */
  
  #define IPV6_ADDR_ANY		0x0000U
  
  #define IPV6_ADDR_UNICAST      	0x0001U	
  #define IPV6_ADDR_MULTICAST    	0x0002U	
  
  #define IPV6_ADDR_LOOPBACK	0x0010U
  #define IPV6_ADDR_LINKLOCAL	0x0020U
  #define IPV6_ADDR_SITELOCAL	0x0040U
  
  #define IPV6_ADDR_COMPATv4	0x0080U
  
  #define IPV6_ADDR_SCOPE_MASK	0x00f0U
  
  #define IPV6_ADDR_MAPPED	0x1000U

  
  /*
   *	Addr scopes
   */

  #define IPV6_ADDR_MC_SCOPE(a)	\
  	((a)->s6_addr[1] & 0x0f)	/* nonstandard */
  #define __IPV6_ADDR_SCOPE_INVALID	-1

  #define IPV6_ADDR_SCOPE_NODELOCAL	0x01
  #define IPV6_ADDR_SCOPE_LINKLOCAL	0x02
  #define IPV6_ADDR_SCOPE_SITELOCAL	0x05
  #define IPV6_ADDR_SCOPE_ORGLOCAL	0x08
  #define IPV6_ADDR_SCOPE_GLOBAL		0x0e
  
  /*

   *	Addr flags
   */

  #define IPV6_ADDR_MC_FLAG_TRANSIENT(a)	\
  	((a)->s6_addr[1] & 0x10)
  #define IPV6_ADDR_MC_FLAG_PREFIX(a)	\
  	((a)->s6_addr[1] & 0x20)
  #define IPV6_ADDR_MC_FLAG_RENDEZVOUS(a)	\
  	((a)->s6_addr[1] & 0x40)

  
  /*

   *	fragmentation header
   */
  
  struct frag_hdr {

  	__u8	nexthdr;
  	__u8	reserved;
  	__be16	frag_off;
  	__be32	identification;

  };

  #define	IP6_MF		0x0001
  #define	IP6_OFFSET	0xFFF8

  #define IP6_REPLY_MARK(net, mark) \
  	((net)->ipv6.sysctl.fwmark_reflect ? (mark) : 0)

  #include <net/sock.h>
  
  /* sysctls */

  extern int sysctl_mld_max_msf;

  extern int sysctl_mld_qrv;

  #define _DEVINC(net, statname, mod, idev, field)			\

  ({									\

  	struct inet6_dev *_idev = (idev);				\
  	if (likely(_idev != NULL))					\

  		mod##SNMP_INC_STATS64((_idev)->stats.statname, (field));\
  	mod##SNMP_INC_STATS64((net)->mib.statname##_statistics, (field));\

  })

  /* per device counters are atomic_long_t */

  #define _DEVINCATOMIC(net, statname, mod, idev, field)			\

  ({									\
  	struct inet6_dev *_idev = (idev);				\
  	if (likely(_idev != NULL))					\
  		SNMP_INC_STATS_ATOMIC_LONG((_idev)->stats.statname##dev, (field)); \

  	mod##SNMP_INC_STATS((net)->mib.statname##_statistics, (field));\

  })

  /* per device and per net counters are atomic_long_t */
  #define _DEVINC_ATOMIC_ATOMIC(net, statname, idev, field)		\
  ({									\
  	struct inet6_dev *_idev = (idev);				\
  	if (likely(_idev != NULL))					\
  		SNMP_INC_STATS_ATOMIC_LONG((_idev)->stats.statname##dev, (field)); \
  	SNMP_INC_STATS_ATOMIC_LONG((net)->mib.statname##_statistics, (field));\
  })

  #define _DEVADD(net, statname, mod, idev, field, val)			\

  ({									\
  	struct inet6_dev *_idev = (idev);				\
  	if (likely(_idev != NULL))					\

  		mod##SNMP_ADD_STATS((_idev)->stats.statname, (field), (val)); \
  	mod##SNMP_ADD_STATS((net)->mib.statname##_statistics, (field), (val));\

  })

  #define _DEVUPD(net, statname, mod, idev, field, val)			\

  ({									\
  	struct inet6_dev *_idev = (idev);				\
  	if (likely(_idev != NULL))					\

  		mod##SNMP_UPD_PO_STATS((_idev)->stats.statname, field, (val)); \
  	mod##SNMP_UPD_PO_STATS((net)->mib.statname##_statistics, field, (val));\

  })

  /* MIBs */

  #define IP6_INC_STATS(net, idev,field)		\

  		_DEVINC(net, ipv6, , idev, field)

  #define __IP6_INC_STATS(net, idev,field)	\

  		_DEVINC(net, ipv6, __, idev, field)

  #define IP6_ADD_STATS(net, idev,field,val)	\

  		_DEVADD(net, ipv6, , idev, field, val)

  #define __IP6_ADD_STATS(net, idev,field,val)	\

  		_DEVADD(net, ipv6, __, idev, field, val)

  #define IP6_UPD_PO_STATS(net, idev,field,val)   \

  		_DEVUPD(net, ipv6, , idev, field, val)

  #define __IP6_UPD_PO_STATS(net, idev,field,val)   \

  		_DEVUPD(net, ipv6, __, idev, field, val)

  #define ICMP6_INC_STATS(net, idev, field)	\

  		_DEVINCATOMIC(net, icmpv6, , idev, field)

  #define __ICMP6_INC_STATS(net, idev, field)	\

  		_DEVINCATOMIC(net, icmpv6, __, idev, field)

  
  #define ICMP6MSGOUT_INC_STATS(net, idev, field)		\

  	_DEVINC_ATOMIC_ATOMIC(net, icmpv6msg, idev, field +256)

  #define ICMP6MSGIN_INC_STATS(net, idev, field)	\

  	_DEVINC_ATOMIC_ATOMIC(net, icmpv6msg, idev, field)

  struct ip6_ra_chain {

  	struct ip6_ra_chain	*next;
  	struct sock		*sk;
  	int			sel;
  	void			(*destructor)(struct sock *);
  };
  
  extern struct ip6_ra_chain	*ip6_ra_chain;
  extern rwlock_t ip6_ra_lock;
  
  /*
     This structure is prepared by protocol, when parsing
     ancillary data and passed to IPv6.
   */

  struct ipv6_txoptions {

  	refcount_t		refcnt;

  	/* Length of this structure */
  	int			tot_len;
  
  	/* length of extension headers   */
  
  	__u16			opt_flen;	/* after fragment hdr */
  	__u16			opt_nflen;	/* before fragment hdr */
  
  	struct ipv6_opt_hdr	*hopopt;
  	struct ipv6_opt_hdr	*dst0opt;
  	struct ipv6_rt_hdr	*srcrt;	/* Routing Header */

  	struct ipv6_opt_hdr	*dst1opt;

  	struct rcu_head		rcu;

  	/* Option buffer, as read by IPV6_PKTOPTIONS, starts here. */
  };

  struct ip6_flowlabel {

  	struct ip6_flowlabel __rcu *next;

  	__be32			label;

  	atomic_t		users;

  	struct in6_addr		dst;
  	struct ipv6_txoptions	*opt;

  	unsigned long		linger;

  	struct rcu_head		rcu;

  	u8			share;

  	union {
  		struct pid *pid;
  		kuid_t uid;
  	} owner;

  	unsigned long		lastuse;
  	unsigned long		expires;

  	struct net		*fl_net;

  };

  #define IPV6_FLOWINFO_MASK		cpu_to_be32(0x0FFFFFFF)
  #define IPV6_FLOWLABEL_MASK		cpu_to_be32(0x000FFFFF)
  #define IPV6_FLOWLABEL_STATELESS_FLAG	cpu_to_be32(0x00080000)

  #define IPV6_TCLASS_MASK (IPV6_FLOWINFO_MASK & ~IPV6_FLOWLABEL_MASK)

  #define IPV6_TCLASS_SHIFT	20

  struct ipv6_fl_socklist {

  	struct ipv6_fl_socklist	__rcu	*next;
  	struct ip6_flowlabel		*fl;
  	struct rcu_head			rcu;

  };

  struct ipcm6_cookie {
  	__s16 hlimit;
  	__s16 tclass;
  	__s8  dontfrag;
  	struct ipv6_txoptions *opt;
  };

  static inline struct ipv6_txoptions *txopt_get(const struct ipv6_pinfo *np)
  {
  	struct ipv6_txoptions *opt;
  
  	rcu_read_lock();
  	opt = rcu_dereference(np->opt);

  	if (opt) {

  		if (!refcount_inc_not_zero(&opt->refcnt))

  			opt = NULL;
  		else
  			opt = rcu_pointer_handoff(opt);
  	}

  	rcu_read_unlock();
  	return opt;
  }
  
  static inline void txopt_put(struct ipv6_txoptions *opt)
  {

  	if (opt && refcount_dec_and_test(&opt->refcnt))

  		kfree_rcu(opt, rcu);
  }

  struct ip6_flowlabel *fl6_sock_lookup(struct sock *sk, __be32 label);
  struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions *opt_space,
  					 struct ip6_flowlabel *fl,
  					 struct ipv6_txoptions *fopt);
  void fl6_free_socklist(struct sock *sk);
  int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen);

  int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
  			   int flags);

  int ip6_flowlabel_init(void);
  void ip6_flowlabel_cleanup(void);

  bool ip6_autoflowlabel(struct net *net, const struct ipv6_pinfo *np);

  
  static inline void fl6_sock_release(struct ip6_flowlabel *fl)
  {
  	if (fl)
  		atomic_dec(&fl->users);
  }

  void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info);

  int icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
  			       struct icmp6hdr *thdr, int len);

  int ip6_ra_control(struct sock *sk, int sel);

  int ipv6_parse_hopopts(struct sk_buff *skb);

  struct ipv6_txoptions *ipv6_dup_options(struct sock *sk,
  					struct ipv6_txoptions *opt);
  struct ipv6_txoptions *ipv6_renew_options(struct sock *sk,
  					  struct ipv6_txoptions *opt,
  					  int newtype,

  					  struct ipv6_opt_hdr *newopt);

  struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
  					  struct ipv6_txoptions *opt);

  bool ipv6_opt_accepted(const struct sock *sk, const struct sk_buff *skb,
  		       const struct inet6_skb_parm *opt);

  struct ipv6_txoptions *ipv6_update_options(struct sock *sk,
  					   struct ipv6_txoptions *opt);

  static inline bool ipv6_accept_ra(struct inet6_dev *idev)
  {
  	/* If forwarding is enabled, RA are not accepted unless the special
  	 * hybrid mode (accept_ra=2) is enabled.
  	 */
  	return idev->cnf.forwarding ? idev->cnf.accept_ra == 2 :
  	    idev->cnf.accept_ra;
  }

  #define IPV6_FRAG_HIGH_THRESH	(4 * 1024*1024)	/* 4194304 */
  #define IPV6_FRAG_LOW_THRESH	(3 * 1024*1024)	/* 3145728 */

  #define IPV6_FRAG_TIMEOUT	(60 * HZ)	/* 60 seconds */

  int __ipv6_addr_type(const struct in6_addr *addr);

  static inline int ipv6_addr_type(const struct in6_addr *addr)
  {
  	return __ipv6_addr_type(addr) & 0xffff;
  }

  
  static inline int ipv6_addr_scope(const struct in6_addr *addr)
  {

  	return __ipv6_addr_type(addr) & IPV6_ADDR_SCOPE_MASK;
  }
  
  static inline int __ipv6_addr_src_scope(int type)
  {

  	return (type == IPV6_ADDR_ANY) ? __IPV6_ADDR_SCOPE_INVALID : (type >> 16);

  }
  
  static inline int ipv6_addr_src_scope(const struct in6_addr *addr)
  {
  	return __ipv6_addr_src_scope(__ipv6_addr_type(addr));

  }

  static inline bool __ipv6_addr_needs_scope_id(int type)
  {
  	return type & IPV6_ADDR_LINKLOCAL ||
  	       (type & IPV6_ADDR_MULTICAST &&
  		(type & (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)));
  }
  
  static inline __u32 ipv6_iface_scope_id(const struct in6_addr *addr, int iface)
  {
  	return __ipv6_addr_needs_scope_id(__ipv6_addr_type(addr)) ? iface : 0;
  }

  static inline int ipv6_addr_cmp(const struct in6_addr *a1, const struct in6_addr *a2)
  {

  	return memcmp(a1, a2, sizeof(struct in6_addr));

  }

  static inline bool

  ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m,
  		     const struct in6_addr *a2)
  {

  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  	const unsigned long *ul1 = (const unsigned long *)a1;
  	const unsigned long *ulm = (const unsigned long *)m;
  	const unsigned long *ul2 = (const unsigned long *)a2;
  
  	return !!(((ul1[0] ^ ul2[0]) & ulm[0]) |
  		  ((ul1[1] ^ ul2[1]) & ulm[1]));
  #else

  	return !!(((a1->s6_addr32[0] ^ a2->s6_addr32[0]) & m->s6_addr32[0]) |
  		  ((a1->s6_addr32[1] ^ a2->s6_addr32[1]) & m->s6_addr32[1]) |
  		  ((a1->s6_addr32[2] ^ a2->s6_addr32[2]) & m->s6_addr32[2]) |
  		  ((a1->s6_addr32[3] ^ a2->s6_addr32[3]) & m->s6_addr32[3]));

  #endif

  }

  static inline void ipv6_addr_prefix(struct in6_addr *pfx, 
  				    const struct in6_addr *addr,
  				    int plen)
  {
  	/* caller must guarantee 0 <= plen <= 128 */
  	int o = plen >> 3,
  	    b = plen & 0x7;

  	memset(pfx->s6_addr, 0, sizeof(pfx->s6_addr));

  	memcpy(pfx->s6_addr, addr, o);

  	if (b != 0)

  		pfx->s6_addr[o] = addr->s6_addr[o] & (0xff00 >> b);

  }

  static inline void ipv6_addr_prefix_copy(struct in6_addr *addr,
  					 const struct in6_addr *pfx,
  					 int plen)
  {
  	/* caller must guarantee 0 <= plen <= 128 */
  	int o = plen >> 3,
  	    b = plen & 0x7;
  
  	memcpy(addr->s6_addr, pfx, o);
  	if (b != 0) {
  		addr->s6_addr[o] &= ~(0xff00 >> b);
  		addr->s6_addr[o] |= (pfx->s6_addr[o] & (0xff00 >> b));
  	}
  }

  static inline void __ipv6_addr_set_half(__be32 *addr,
  					__be32 wh, __be32 wl)
  {
  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  #if defined(__BIG_ENDIAN)
  	if (__builtin_constant_p(wh) && __builtin_constant_p(wl)) {
  		*(__force u64 *)addr = ((__force u64)(wh) << 32 | (__force u64)(wl));
  		return;
  	}
  #elif defined(__LITTLE_ENDIAN)
  	if (__builtin_constant_p(wl) && __builtin_constant_p(wh)) {
  		*(__force u64 *)addr = ((__force u64)(wl) << 32 | (__force u64)(wh));
  		return;
  	}
  #endif
  #endif
  	addr[0] = wh;
  	addr[1] = wl;
  }

  static inline void ipv6_addr_set(struct in6_addr *addr, 

  				     __be32 w1, __be32 w2,
  				     __be32 w3, __be32 w4)

  {

  	__ipv6_addr_set_half(&addr->s6_addr32[0], w1, w2);
  	__ipv6_addr_set_half(&addr->s6_addr32[2], w3, w4);

  }

  static inline bool ipv6_addr_equal(const struct in6_addr *a1,
  				   const struct in6_addr *a2)

  {

  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  	const unsigned long *ul1 = (const unsigned long *)a1;
  	const unsigned long *ul2 = (const unsigned long *)a2;
  
  	return ((ul1[0] ^ ul2[0]) | (ul1[1] ^ ul2[1])) == 0UL;
  #else

  	return ((a1->s6_addr32[0] ^ a2->s6_addr32[0]) |
  		(a1->s6_addr32[1] ^ a2->s6_addr32[1]) |
  		(a1->s6_addr32[2] ^ a2->s6_addr32[2]) |
  		(a1->s6_addr32[3] ^ a2->s6_addr32[3])) == 0;

  #endif

  }

  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  static inline bool __ipv6_prefix_equal64_half(const __be64 *a1,
  					      const __be64 *a2,
  					      unsigned int len)
  {

  	if (len && ((*a1 ^ *a2) & cpu_to_be64((~0UL) << (64 - len))))

  		return false;
  	return true;
  }
  
  static inline bool ipv6_prefix_equal(const struct in6_addr *addr1,
  				     const struct in6_addr *addr2,
  				     unsigned int prefixlen)
  {
  	const __be64 *a1 = (const __be64 *)addr1;
  	const __be64 *a2 = (const __be64 *)addr2;
  
  	if (prefixlen >= 64) {
  		if (a1[0] ^ a2[0])
  			return false;
  		return __ipv6_prefix_equal64_half(a1 + 1, a2 + 1, prefixlen - 64);
  	}
  	return __ipv6_prefix_equal64_half(a1, a2, prefixlen);
  }
  #else

  static inline bool ipv6_prefix_equal(const struct in6_addr *addr1,
  				     const struct in6_addr *addr2,
  				     unsigned int prefixlen)

  {

  	const __be32 *a1 = addr1->s6_addr32;
  	const __be32 *a2 = addr2->s6_addr32;

  	unsigned int pdw, pbi;

  
  	/* check complete u32 in prefix */
  	pdw = prefixlen >> 5;
  	if (pdw && memcmp(a1, a2, pdw << 2))

  		return false;

  
  	/* check incomplete u32 in prefix */
  	pbi = prefixlen & 0x1f;
  	if (pbi && ((a1[pdw] ^ a2[pdw]) & htonl((0xffffffff) << (32 - pbi))))

  		return false;

  	return true;

  }

  #endif

  struct inet_frag_queue;

  enum ip6_defrag_users {
  	IP6_DEFRAG_LOCAL_DELIVER,
  	IP6_DEFRAG_CONNTRACK_IN,

  	__IP6_DEFRAG_CONNTRACK_IN	= IP6_DEFRAG_CONNTRACK_IN + USHRT_MAX,

  	IP6_DEFRAG_CONNTRACK_OUT,

  	__IP6_DEFRAG_CONNTRACK_OUT	= IP6_DEFRAG_CONNTRACK_OUT + USHRT_MAX,

  	IP6_DEFRAG_CONNTRACK_BRIDGE_IN,

  	__IP6_DEFRAG_CONNTRACK_BRIDGE_IN = IP6_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,

  };

  void ip6_frag_init(struct inet_frag_queue *q, const void *a);

  extern const struct rhashtable_params ip6_rhash_params;

  /*
   *	Equivalent of ipv4 struct ip
   */
  struct frag_queue {
  	struct inet_frag_queue	q;

  	int			iif;
  	unsigned int		csum;
  	__u16			nhoffset;

  	u8			ecn;

  };

  void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq);

  static inline bool ipv6_addr_any(const struct in6_addr *a)

  {

  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  	const unsigned long *ul = (const unsigned long *)a;
  
  	return (ul[0] | ul[1]) == 0UL;
  #else

  	return (a->s6_addr32[0] | a->s6_addr32[1] |
  		a->s6_addr32[2] | a->s6_addr32[3]) == 0;

  #endif

  }

  static inline u32 ipv6_addr_hash(const struct in6_addr *a)
  {
  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  	const unsigned long *ul = (const unsigned long *)a;
  	unsigned long x = ul[0] ^ ul[1];
  
  	return (u32)(x ^ (x >> 32));
  #else
  	return (__force u32)(a->s6_addr32[0] ^ a->s6_addr32[1] ^
  			     a->s6_addr32[2] ^ a->s6_addr32[3]);
  #endif
  }

  /* more secured version of ipv6_addr_hash() */

  static inline u32 __ipv6_addr_jhash(const struct in6_addr *a, const u32 initval)

  {
  	u32 v = (__force u32)a->s6_addr32[0] ^ (__force u32)a->s6_addr32[1];
  
  	return jhash_3words(v,
  			    (__force u32)a->s6_addr32[2],
  			    (__force u32)a->s6_addr32[3],

  			    initval);

  }

  static inline bool ipv6_addr_loopback(const struct in6_addr *a)

  {

  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64

  	const __be64 *be = (const __be64 *)a;

  	return (be[0] | (be[1] ^ cpu_to_be64(1))) == 0UL;

  #else

  	return (a->s6_addr32[0] | a->s6_addr32[1] |

  		a->s6_addr32[2] | (a->s6_addr32[3] ^ cpu_to_be32(1))) == 0;

  #endif

  }

  /*
   * Note that we must __force cast these to unsigned long to make sparse happy,
   * since all of the endian-annotated types are fixed size regardless of arch.
   */

  static inline bool ipv6_addr_v4mapped(const struct in6_addr *a)

  {

  	return (
  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64

  		*(unsigned long *)a |

  #else

  		(__force unsigned long)(a->s6_addr32[0] | a->s6_addr32[1]) |

  #endif

  		(__force unsigned long)(a->s6_addr32[2] ^
  					cpu_to_be32(0x0000ffff))) == 0UL;

  }

  /*

   * Check for a RFC 4843 ORCHID address
   * (Overlay Routable Cryptographic Hash Identifiers)
   */

  static inline bool ipv6_addr_orchid(const struct in6_addr *a)

  {

  	return (a->s6_addr32[0] & htonl(0xfffffff0)) == htonl(0x20010010);

  }

  static inline bool ipv6_addr_is_multicast(const struct in6_addr *addr)
  {
  	return (addr->s6_addr32[0] & htonl(0xFF000000)) == htonl(0xFF000000);
  }

  static inline void ipv6_addr_set_v4mapped(const __be32 addr,
  					  struct in6_addr *v4mapped)
  {
  	ipv6_addr_set(v4mapped,
  			0, 0,
  			htonl(0x0000FFFF),
  			addr);
  }

  /*

   * find the first different bit between two addresses
   * length of address must be a multiple of 32bits
   */

  static inline int __ipv6_addr_diff32(const void *token1, const void *token2, int addrlen)

  {

  	const __be32 *a1 = token1, *a2 = token2;

  	int i;
  
  	addrlen >>= 2;
  
  	for (i = 0; i < addrlen; i++) {

  		__be32 xb = a1[i] ^ a2[i];
  		if (xb)

  			return i * 32 + 31 - __fls(ntohl(xb));

  	}
  
  	/*
  	 *	we should *never* get to this point since that 
  	 *	would mean the addrs are equal
  	 *
  	 *	However, we do get to it 8) And exacly, when
  	 *	addresses are equal 8)
  	 *
  	 *	ip route add 1111::/128 via ...
  	 *	ip route add 1111::/64 via ...
  	 *	and we are here.
  	 *
  	 *	Ideally, this function should stop comparison
  	 *	at prefix length. It does not, but it is still OK,
  	 *	if returned value is greater than prefix length.
  	 *					--ANK (980803)
  	 */

  	return addrlen << 5;

  }

  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  static inline int __ipv6_addr_diff64(const void *token1, const void *token2, int addrlen)
  {
  	const __be64 *a1 = token1, *a2 = token2;
  	int i;
  
  	addrlen >>= 3;
  
  	for (i = 0; i < addrlen; i++) {
  		__be64 xb = a1[i] ^ a2[i];
  		if (xb)
  			return i * 64 + 63 - __fls(be64_to_cpu(xb));
  	}
  
  	return addrlen << 6;
  }
  #endif
  
  static inline int __ipv6_addr_diff(const void *token1, const void *token2, int addrlen)
  {
  #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
  	if (__builtin_constant_p(addrlen) && !(addrlen & 7))
  		return __ipv6_addr_diff64(token1, token2, addrlen);
  #endif
  	return __ipv6_addr_diff32(token1, token2, addrlen);
  }

  static inline int ipv6_addr_diff(const struct in6_addr *a1, const struct in6_addr *a2)
  {
  	return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr));
  }

  __be32 ipv6_select_ident(struct net *net,
  			 const struct in6_addr *daddr,
  			 const struct in6_addr *saddr);

  __be32 ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb);

  int ip6_dst_hoplimit(struct dst_entry *dst);

  static inline int ip6_sk_dst_hoplimit(struct ipv6_pinfo *np, struct flowi6 *fl6,
  				      struct dst_entry *dst)
  {
  	int hlimit;
  
  	if (ipv6_addr_is_multicast(&fl6->daddr))
  		hlimit = np->mcast_hops;
  	else
  		hlimit = np->hop_limit;
  	if (hlimit < 0)
  		hlimit = ip6_dst_hoplimit(dst);
  	return hlimit;
  }

  /* copy IPv6 saddr & daddr to flow_keys, possibly using 64bit load/store
   * Equivalent to :	flow->v6addrs.src = iph->saddr;
   *			flow->v6addrs.dst = iph->daddr;
   */
  static inline void iph_to_flow_copy_v6addrs(struct flow_keys *flow,
  					    const struct ipv6hdr *iph)
  {
  	BUILD_BUG_ON(offsetof(typeof(flow->addrs), v6addrs.dst) !=
  		     offsetof(typeof(flow->addrs), v6addrs.src) +
  		     sizeof(flow->addrs.v6addrs.src));
  	memcpy(&flow->addrs.v6addrs, &iph->saddr, sizeof(flow->addrs.v6addrs));
  	flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
  }

  #if IS_ENABLED(CONFIG_IPV6)

  
  /* Sysctl settings for net ipv6.auto_flowlabels */
  #define IP6_AUTO_FLOW_LABEL_OFF		0
  #define IP6_AUTO_FLOW_LABEL_OPTOUT	1
  #define IP6_AUTO_FLOW_LABEL_OPTIN	2
  #define IP6_AUTO_FLOW_LABEL_FORCED	3
  
  #define IP6_AUTO_FLOW_LABEL_MAX		IP6_AUTO_FLOW_LABEL_FORCED

  #define IP6_DEFAULT_AUTO_FLOW_LABELS	IP6_AUTO_FLOW_LABEL_OPTOUT

  static inline __be32 ip6_make_flowlabel(struct net *net, struct sk_buff *skb,

  					__be32 flowlabel, bool autolabel,
  					struct flowi6 *fl6)

  {

  	u32 hash;

  	/* @flowlabel may include more than a flow label, eg, the traffic class.
  	 * Here we want only the flow label value.
  	 */
  	flowlabel &= IPV6_FLOWLABEL_MASK;

  	if (flowlabel ||
  	    net->ipv6.sysctl.auto_flowlabels == IP6_AUTO_FLOW_LABEL_OFF ||
  	    (!autolabel &&
  	     net->ipv6.sysctl.auto_flowlabels != IP6_AUTO_FLOW_LABEL_FORCED))
  		return flowlabel;

  	hash = skb_get_hash_flowi6(skb, fl6);

  	/* Since this is being sent on the wire obfuscate hash a bit
  	 * to minimize possbility that any useful information to an
  	 * attacker is leaked. Only lower 20 bits are relevant.
  	 */

  	hash = rol32(hash, 16);

  	flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
  
  	if (net->ipv6.sysctl.flowlabel_state_ranges)
  		flowlabel |= IPV6_FLOWLABEL_STATELESS_FLAG;

  
  	return flowlabel;
  }

  
  static inline int ip6_default_np_autolabel(struct net *net)
  {
  	switch (net->ipv6.sysctl.auto_flowlabels) {
  	case IP6_AUTO_FLOW_LABEL_OFF:
  	case IP6_AUTO_FLOW_LABEL_OPTIN:
  	default:
  		return 0;
  	case IP6_AUTO_FLOW_LABEL_OPTOUT:
  	case IP6_AUTO_FLOW_LABEL_FORCED:
  		return 1;
  	}
  }

  #else
  static inline void ip6_set_txhash(struct sock *sk) { }
  static inline __be32 ip6_make_flowlabel(struct net *net, struct sk_buff *skb,

  					__be32 flowlabel, bool autolabel,
  					struct flowi6 *fl6)

  {
  	return flowlabel;
  }

  static inline int ip6_default_np_autolabel(struct net *net)
  {
  	return 0;
  }

  #endif

  /*

   *	Header manipulation
   */
  static inline void ip6_flow_hdr(struct ipv6hdr *hdr, unsigned int tclass,
  				__be32 flowlabel)
  {

  	*(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | flowlabel;

  }

  static inline __be32 ip6_flowinfo(const struct ipv6hdr *hdr)
  {
  	return *(__be32 *)hdr & IPV6_FLOWINFO_MASK;
  }

  static inline __be32 ip6_flowlabel(const struct ipv6hdr *hdr)
  {
  	return *(__be32 *)hdr & IPV6_FLOWLABEL_MASK;
  }

  static inline u8 ip6_tclass(__be32 flowinfo)
  {
  	return ntohl(flowinfo & IPV6_TCLASS_MASK) >> IPV6_TCLASS_SHIFT;
  }

  
  static inline __be32 ip6_make_flowinfo(unsigned int tclass, __be32 flowlabel)
  {
  	return htonl(tclass << IPV6_TCLASS_SHIFT) | flowlabel;
  }

  static inline __be32 flowi6_get_flowlabel(const struct flowi6 *fl6)
  {
  	return fl6->flowlabel & IPV6_FLOWLABEL_MASK;
  }

  /*

   *	Prototypes exported by ipv6
   */
  
  /*
   *	rcv function (called from netdevice level)
   */

  int ipv6_rcv(struct sk_buff *skb, struct net_device *dev,
  	     struct packet_type *pt, struct net_device *orig_dev);

  int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb);

  /*
   *	upper-layer output functions
   */

  int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,

  	     __u32 mark, struct ipv6_txoptions *opt, int tclass);

  
  int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr);
  
  int ip6_append_data(struct sock *sk,
  		    int getfrag(void *from, char *to, int offset, int len,
  				int odd, struct sk_buff *skb),

  		    void *from, int length, int transhdrlen,
  		    struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
  		    struct rt6_info *rt, unsigned int flags,

  		    const struct sockcm_cookie *sockc);

  
  int ip6_push_pending_frames(struct sock *sk);
  
  void ip6_flush_pending_frames(struct sock *sk);

  int ip6_send_skb(struct sk_buff *skb);
  
  struct sk_buff *__ip6_make_skb(struct sock *sk, struct sk_buff_head *queue,
  			       struct inet_cork_full *cork,
  			       struct inet6_cork *v6_cork);
  struct sk_buff *ip6_make_skb(struct sock *sk,
  			     int getfrag(void *from, char *to, int offset,
  					 int len, int odd, struct sk_buff *skb),
  			     void *from, int length, int transhdrlen,

  			     struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
  			     struct rt6_info *rt, unsigned int flags,

  			     const struct sockcm_cookie *sockc);

  
  static inline struct sk_buff *ip6_finish_skb(struct sock *sk)
  {
  	return __ip6_make_skb(sk, &sk->sk_write_queue, &inet_sk(sk)->cork,
  			      &inet6_sk(sk)->cork);
  }

  int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
  		   struct flowi6 *fl6);

  struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,

  				      const struct in6_addr *final_dst);

  struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,

  					 const struct in6_addr *final_dst);

  struct dst_entry *ip6_blackhole_route(struct net *net,
  				      struct dst_entry *orig_dst);

  
  /*
   *	skb processing functions
   */

  int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb);

  int ip6_forward(struct sk_buff *skb);
  int ip6_input(struct sk_buff *skb);
  int ip6_mc_input(struct sk_buff *skb);

  int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);

  int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);

  /*
   *	Extension header (options) processing
   */

  void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,

  			  u8 *proto, struct in6_addr **daddr_p,
  			  struct in6_addr *saddr);

  void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
  			 u8 *proto);

  int ipv6_skip_exthdr(const struct sk_buff *, int start, u8 *nexthdrp,
  		     __be16 *frag_offp);

  bool ipv6_ext_hdr(u8 nexthdr);

  enum {

  	IP6_FH_F_FRAG		= (1 << 0),
  	IP6_FH_F_AUTH		= (1 << 1),
  	IP6_FH_F_SKIP_RH	= (1 << 2),

  };
  
  /* find specified header and get offset to it */

  int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, int target,
  		  unsigned short *fragoff, int *fragflg);

  int ipv6_find_tlv(const struct sk_buff *skb, int offset, int type);

  struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
  				const struct ipv6_txoptions *opt,
  				struct in6_addr *orig);

  /*
   *	socket options (ipv6_sockglue.c)
   */

  int ipv6_setsockopt(struct sock *sk, int level, int optname,
  		    char __user *optval, unsigned int optlen);
  int ipv6_getsockopt(struct sock *sk, int level, int optname,
  		    char __user *optval, int __user *optlen);
  int compat_ipv6_setsockopt(struct sock *sk, int level, int optname,
  			   char __user *optval, unsigned int optlen);
  int compat_ipv6_getsockopt(struct sock *sk, int level, int optname,
  			   char __user *optval, int __user *optlen);

  int __ip6_datagram_connect(struct sock *sk, struct sockaddr *addr,
  			   int addr_len);

  int ip6_datagram_connect(struct sock *sk, struct sockaddr *addr, int addr_len);

  int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *addr,
  				 int addr_len);

  int ip6_datagram_dst_update(struct sock *sk, bool fix_sk_saddr);

  void ip6_datagram_release_cb(struct sock *sk);

  int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
  		    int *addr_len);
  int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len,
  		     int *addr_len);

  void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
  		     u32 info, u8 *payload);
  void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info);
  void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu);
  
  int inet6_release(struct socket *sock);
  int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len);
  int inet6_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len,
  		  int peer);
  int inet6_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
  
  int inet6_hash_connect(struct inet_timewait_death_row *death_row,

  			      struct sock *sk);

  /*
   * reassembly.c
   */

  extern const struct proto_ops inet6_stream_ops;
  extern const struct proto_ops inet6_dgram_ops;

  extern const struct proto_ops inet6_sockraw_ops;

  struct group_source_req;
  struct group_filter;

  int ip6_mc_source(int add, int omode, struct sock *sk,
  		  struct group_source_req *pgsr);
  int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf);
  int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
  		  struct group_filter __user *optval, int __user *optlen);

  
  #ifdef CONFIG_PROC_FS

  int ac6_proc_init(struct net *net);
  void ac6_proc_exit(struct net *net);
  int raw6_proc_init(void);
  void raw6_proc_exit(void);
  int tcp6_proc_init(struct net *net);
  void tcp6_proc_exit(struct net *net);
  int udp6_proc_init(struct net *net);
  void udp6_proc_exit(struct net *net);
  int udplite6_proc_init(void);
  void udplite6_proc_exit(void);
  int ipv6_misc_proc_init(void);
  void ipv6_misc_proc_exit(void);
  int snmp6_register_dev(struct inet6_dev *idev);
  int snmp6_unregister_dev(struct inet6_dev *idev);

  #else

  static inline int ac6_proc_init(struct net *net) { return 0; }
  static inline void ac6_proc_exit(struct net *net) { }
  static inline int snmp6_register_dev(struct inet6_dev *idev) { return 0; }
  static inline int snmp6_unregister_dev(struct inet6_dev *idev) { return 0; }

  #endif

  #ifdef CONFIG_SYSCTL

  extern struct ctl_table ipv6_route_table_template[];

  struct ctl_table *ipv6_icmp_sysctl_init(struct net *net);
  struct ctl_table *ipv6_route_sysctl_init(struct net *net);
  int ipv6_sysctl_register(void);
  void ipv6_sysctl_unregister(void);

  #endif

  int ipv6_sock_mc_join(struct sock *sk, int ifindex,
  		      const struct in6_addr *addr);

  int ipv6_sock_mc_drop(struct sock *sk, int ifindex,
  		      const struct in6_addr *addr);

  #endif /* _NET_IPV6_H */