#ifndef _NET_NEIGHBOUR_H
  #define _NET_NEIGHBOUR_H
  
  #include <linux/neighbour.h>
  
  /*
   *	Generic neighbour manipulation
   *
   *	Authors:
   *	Pedro Roque		<roque@di.fc.ul.pt>
   *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
   *
   * 	Changes:
   *
   *	Harald Welte:		<laforge@gnumonks.org>
   *		- Add neighbour cache statistics like rtstat
   */
  
  #include <linux/atomic.h>
  #include <linux/netdevice.h>
  #include <linux/skbuff.h>
  #include <linux/rcupdate.h>
  #include <linux/seq_file.h>
  #include <linux/bitmap.h>
  
  #include <linux/err.h>
  #include <linux/sysctl.h>
  #include <linux/workqueue.h>
  #include <net/rtnetlink.h>
  
  /*
   * NUD stands for "neighbor unreachability detection"
   */
  
  #define NUD_IN_TIMER	(NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
  #define NUD_VALID	(NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
  #define NUD_CONNECTED	(NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
  
  struct neighbour;
  
  enum {
  	NEIGH_VAR_MCAST_PROBES,
  	NEIGH_VAR_UCAST_PROBES,
  	NEIGH_VAR_APP_PROBES,
  	NEIGH_VAR_RETRANS_TIME,
  	NEIGH_VAR_BASE_REACHABLE_TIME,
  	NEIGH_VAR_DELAY_PROBE_TIME,
  	NEIGH_VAR_GC_STALETIME,
  	NEIGH_VAR_QUEUE_LEN_BYTES,
  	NEIGH_VAR_PROXY_QLEN,
  	NEIGH_VAR_ANYCAST_DELAY,
  	NEIGH_VAR_PROXY_DELAY,
  	NEIGH_VAR_LOCKTIME,
  #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
  	/* Following are used as a second way to access one of the above */
  	NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
  	NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
  	NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
  	/* Following are used by "default" only */
  	NEIGH_VAR_GC_INTERVAL,
  	NEIGH_VAR_GC_THRESH1,
  	NEIGH_VAR_GC_THRESH2,
  	NEIGH_VAR_GC_THRESH3,
  	NEIGH_VAR_MAX
  };
  
  struct neigh_parms {
  #ifdef CONFIG_NET_NS
  	struct net *net;
  #endif
  	struct net_device *dev;
  	struct neigh_parms *next;
  	int	(*neigh_setup)(struct neighbour *);
  	void	(*neigh_cleanup)(struct neighbour *);
  	struct neigh_table *tbl;
  
  	void	*sysctl_table;
  
  	int dead;
  	atomic_t refcnt;
  	struct rcu_head rcu_head;
  
  	int	reachable_time;
  	int	data[NEIGH_VAR_DATA_MAX];
  	DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
  };
  
  static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
  {
  	set_bit(index, p->data_state);
  	p->data[index] = val;
  }
  
  #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
  
  /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
   * In other cases, NEIGH_VAR_SET should be used.
   */
  #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
  #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
  
  static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
  {
  	bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
  }
  
  static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
  {
  	bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
  }
  
  struct neigh_statistics {
  	unsigned long allocs;		/* number of allocated neighs */
  	unsigned long destroys;		/* number of destroyed neighs */
  	unsigned long hash_grows;	/* number of hash resizes */
  
  	unsigned long res_failed;	/* number of failed resolutions */
  
  	unsigned long lookups;		/* number of lookups */
  	unsigned long hits;		/* number of hits (among lookups) */
  
  	unsigned long rcv_probes_mcast;	/* number of received mcast ipv6 */
  	unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
  
  	unsigned long periodic_gc_runs;	/* number of periodic GC runs */
  	unsigned long forced_gc_runs;	/* number of forced GC runs */
  
  	unsigned long unres_discards;	/* number of unresolved drops */
  };
  
  #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
  
  struct neighbour {
  	struct neighbour __rcu	*next;
  	struct neigh_table	*tbl;
  	struct neigh_parms	*parms;
  	unsigned long		confirmed;
  	unsigned long		updated;
  	rwlock_t		lock;
  	atomic_t		refcnt;
  	struct sk_buff_head	arp_queue;
  	unsigned int		arp_queue_len_bytes;
  	struct timer_list	timer;
  	unsigned long		used;
  	atomic_t		probes;
  	__u8			flags;
  	__u8			nud_state;
  	__u8			type;
  	__u8			dead;
  	seqlock_t		ha_lock;
  	unsigned char		ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
  	struct hh_cache		hh;
  	int			(*output)(struct neighbour *, struct sk_buff *);
  	const struct neigh_ops	*ops;
  	struct rcu_head		rcu;
  	struct net_device	*dev;
  	u8			primary_key[0];
  };
  
  struct neigh_ops {
  	int			family;
  	void			(*solicit)(struct neighbour *, struct sk_buff *);
  	void			(*error_report)(struct neighbour *, struct sk_buff *);
  	int			(*output)(struct neighbour *, struct sk_buff *);
  	int			(*connected_output)(struct neighbour *, struct sk_buff *);
  };
  
  struct pneigh_entry {
  	struct pneigh_entry	*next;
  #ifdef CONFIG_NET_NS
  	struct net		*net;
  #endif
  	struct net_device	*dev;
  	u8			flags;
  	u8			key[0];
  };
  
  /*
   *	neighbour table manipulation
   */
  
  #define NEIGH_NUM_HASH_RND	4
  
  struct neigh_hash_table {
  	struct neighbour __rcu	**hash_buckets;
  	unsigned int		hash_shift;
  	__u32			hash_rnd[NEIGH_NUM_HASH_RND];
  	struct rcu_head		rcu;
  };
  
  
  struct neigh_table {
  	struct neigh_table	*next;
  	int			family;
  	int			entry_size;
  	int			key_len;
  	__u32			(*hash)(const void *pkey,
  					const struct net_device *dev,
  					__u32 *hash_rnd);
  	int			(*constructor)(struct neighbour *);
  	int			(*pconstructor)(struct pneigh_entry *);
  	void			(*pdestructor)(struct pneigh_entry *);
  	void			(*proxy_redo)(struct sk_buff *skb);
  	char			*id;
  	struct neigh_parms	parms;
  	/* HACK. gc_* should follow parms without a gap! */
  	int			gc_interval;
  	int			gc_thresh1;
  	int			gc_thresh2;
  	int			gc_thresh3;
  	unsigned long		last_flush;
  	struct delayed_work	gc_work;
  	struct timer_list 	proxy_timer;
  	struct sk_buff_head	proxy_queue;
  	atomic_t		entries;
  	rwlock_t		lock;
  	unsigned long		last_rand;
  	struct neigh_statistics	__percpu *stats;
  	struct neigh_hash_table __rcu *nht;
  	struct pneigh_entry	**phash_buckets;
  };
  
  static inline int neigh_parms_family(struct neigh_parms *p)
  {
  	return p->tbl->family;
  }
  
  #define NEIGH_PRIV_ALIGN	sizeof(long long)
  #define NEIGH_ENTRY_SIZE(size)	ALIGN((size), NEIGH_PRIV_ALIGN)
  
  static inline void *neighbour_priv(const struct neighbour *n)
  {
  	return (char *)n + n->tbl->entry_size;
  }
  
  /* flags for neigh_update() */
  #define NEIGH_UPDATE_F_OVERRIDE			0x00000001
  #define NEIGH_UPDATE_F_WEAK_OVERRIDE		0x00000002
  #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER	0x00000004
  #define NEIGH_UPDATE_F_ISROUTER			0x40000000
  #define NEIGH_UPDATE_F_ADMIN			0x80000000
  
  void neigh_table_init(struct neigh_table *tbl);
  int neigh_table_clear(struct neigh_table *tbl);
  struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
  			       struct net_device *dev);
  struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
  				     const void *pkey);
  struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
  				 struct net_device *dev, bool want_ref);
  static inline struct neighbour *neigh_create(struct neigh_table *tbl,
  					     const void *pkey,
  					     struct net_device *dev)
  {
  	return __neigh_create(tbl, pkey, dev, true);
  }
  void neigh_destroy(struct neighbour *neigh);
  int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
  int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags);
  void __neigh_set_probe_once(struct neighbour *neigh);
  void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
  int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
  int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
  int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
  int neigh_compat_output(struct neighbour *neigh, struct sk_buff *skb);
  int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
  struct neighbour *neigh_event_ns(struct neigh_table *tbl,
  						u8 *lladdr, void *saddr,
  						struct net_device *dev);
  
  struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
  				      struct neigh_table *tbl);
  void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
  
  static inline
  struct net *neigh_parms_net(const struct neigh_parms *parms)
  {
  	return read_pnet(&parms->net);
  }
  
  unsigned long neigh_rand_reach_time(unsigned long base);
  
  void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
  		    struct sk_buff *skb);
  struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
  				   const void *key, struct net_device *dev,
  				   int creat);
  struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
  				     const void *key, struct net_device *dev);
  int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
  		  struct net_device *dev);
  
  static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
  {
  	return read_pnet(&pneigh->net);
  }
  
  void neigh_app_ns(struct neighbour *n);
  void neigh_for_each(struct neigh_table *tbl,
  		    void (*cb)(struct neighbour *, void *), void *cookie);
  void __neigh_for_each_release(struct neigh_table *tbl,
  			      int (*cb)(struct neighbour *));
  void pneigh_for_each(struct neigh_table *tbl,
  		     void (*cb)(struct pneigh_entry *));
  
  struct neigh_seq_state {
  	struct seq_net_private p;
  	struct neigh_table *tbl;
  	struct neigh_hash_table *nht;
  	void *(*neigh_sub_iter)(struct neigh_seq_state *state,
  				struct neighbour *n, loff_t *pos);
  	unsigned int bucket;
  	unsigned int flags;
  #define NEIGH_SEQ_NEIGH_ONLY	0x00000001
  #define NEIGH_SEQ_IS_PNEIGH	0x00000002
  #define NEIGH_SEQ_SKIP_NOARP	0x00000004
  };
  void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
  		      unsigned int);
  void *neigh_seq_next(struct seq_file *, void *, loff_t *);
  void neigh_seq_stop(struct seq_file *, void *);
  
  int neigh_proc_dointvec(struct ctl_table *ctl, int write,
  			void __user *buffer, size_t *lenp, loff_t *ppos);
  int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
  				void __user *buffer,
  				size_t *lenp, loff_t *ppos);
  int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
  				   void __user *buffer,
  				   size_t *lenp, loff_t *ppos);
  
  int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
  			  proc_handler *proc_handler);
  void neigh_sysctl_unregister(struct neigh_parms *p);
  
  static inline void __neigh_parms_put(struct neigh_parms *parms)
  {
  	atomic_dec(&parms->refcnt);
  }
  
  static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
  {
  	atomic_inc(&parms->refcnt);
  	return parms;
  }
  
  /*
   *	Neighbour references
   */
  
  static inline void neigh_release(struct neighbour *neigh)
  {
  	if (atomic_dec_and_test(&neigh->refcnt))
  		neigh_destroy(neigh);
  }
  
  static inline struct neighbour * neigh_clone(struct neighbour *neigh)
  {
  	if (neigh)
  		atomic_inc(&neigh->refcnt);
  	return neigh;
  }
  
  #define neigh_hold(n)	atomic_inc(&(n)->refcnt)
  
  static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
  {
  	unsigned long now = jiffies;
  	
  	if (neigh->used != now)
  		neigh->used = now;
  	if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
  		return __neigh_event_send(neigh, skb);
  	return 0;
  }
  
  #ifdef CONFIG_BRIDGE_NETFILTER
  static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
  {
  	unsigned int seq, hh_alen;
  
  	do {
  		seq = read_seqbegin(&hh->hh_lock);
  		hh_alen = HH_DATA_ALIGN(ETH_HLEN);
  		memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
  	} while (read_seqretry(&hh->hh_lock, seq));
  	return 0;
  }
  #endif
  
  static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
  {
  	unsigned int seq;
  	int hh_len;
  
  	do {
  		seq = read_seqbegin(&hh->hh_lock);
  		hh_len = hh->hh_len;
  		if (likely(hh_len <= HH_DATA_MOD)) {
  			/* this is inlined by gcc */
  			memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD);
  		} else {
  			int hh_alen = HH_DATA_ALIGN(hh_len);
  
  			memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
  		}
  	} while (read_seqretry(&hh->hh_lock, seq));
  
  	skb_push(skb, hh_len);
  	return dev_queue_xmit(skb);
  }
  
  static inline struct neighbour *
  __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
  {
  	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
  
  	if (n || !creat)
  		return n;
  
  	n = neigh_create(tbl, pkey, dev);
  	return IS_ERR(n) ? NULL : n;
  }
  
  static inline struct neighbour *
  __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
    struct net_device *dev)
  {
  	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
  
  	if (n)
  		return n;
  
  	return neigh_create(tbl, pkey, dev);
  }
  
  struct neighbour_cb {
  	unsigned long sched_next;
  	unsigned int flags;
  };
  
  #define LOCALLY_ENQUEUED 0x1
  
  #define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
  
  static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
  				     const struct net_device *dev)
  {
  	unsigned int seq;
  
  	do {
  		seq = read_seqbegin(&n->ha_lock);
  		memcpy(dst, n->ha, dev->addr_len);
  	} while (read_seqretry(&n->ha_lock, seq));
  }
  #endif