/* SPDX-License-Identifier: GPL-2.0 */

  #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/refcount.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_MCAST_REPROBES,

  	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 {

  	possible_net_t net;

  	struct net_device *dev;

  	struct list_head list;

  	int	(*neigh_setup)(struct neighbour *);

  	struct neigh_table *tbl;

  
  	void	*sysctl_table;
  
  	int dead;

  	refcount_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 */

  	unsigned long table_fulls;      /* times even gc couldn't help */

  };

  #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;

  	refcount_t		refcnt;

  	unsigned int		arp_queue_len_bytes;

  	struct sk_buff_head	arp_queue;

  	struct timer_list	timer;
  	unsigned long		used;

  	atomic_t		probes;

  	__u8			flags;
  	__u8			nud_state;
  	__u8			type;
  	__u8			dead;

  	u8			protocol;

  	seqlock_t		ha_lock;

  	unsigned char		ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);

  	struct hh_cache		hh;

  	int			(*output)(struct neighbour *, struct sk_buff *);

  	const struct neigh_ops	*ops;

  	struct list_head	gc_list;

  	struct rcu_head		rcu;

  	struct net_device	*dev;

  	u8			primary_key[0];

  } __randomize_layout;

  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;

  	possible_net_t		net;

  	struct net_device	*dev;

  	u8			flags;

  	u8			protocol;

  	u8			key[];

  };
  
  /*
   *	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 {

  	int			family;

  	unsigned int		entry_size;

  	unsigned int		key_len;

  	__be16			protocol;

  	__u32			(*hash)(const void *pkey,
  					const struct net_device *dev,

  					__u32 *hash_rnd);

  	bool			(*key_eq)(const struct neighbour *, const void *pkey);

  	int			(*constructor)(struct neighbour *);
  	int			(*pconstructor)(struct pneigh_entry *);
  	void			(*pdestructor)(struct pneigh_entry *);
  	void			(*proxy_redo)(struct sk_buff *skb);

  	int			(*is_multicast)(const void *pkey);

  	bool			(*allow_add)(const struct net_device *dev,
  					     struct netlink_ext_ack *extack);

  	char			*id;
  	struct neigh_parms	parms;

  	struct list_head	parms_list;

  	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;

  	atomic_t		gc_entries;
  	struct list_head	gc_list;

  	rwlock_t		lock;
  	unsigned long		last_rand;

  	struct neigh_statistics	__percpu *stats;

  	struct neigh_hash_table __rcu *nht;

  	struct pneigh_entry	**phash_buckets;

  };

  enum {
  	NEIGH_ARP_TABLE = 0,
  	NEIGH_ND_TABLE = 1,
  	NEIGH_DN_TABLE = 2,
  	NEIGH_NR_TABLES,

  	NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */

  };

  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_EXT_LEARNED		0x20000000

  #define NEIGH_UPDATE_F_ISROUTER			0x40000000
  #define NEIGH_UPDATE_F_ADMIN			0x80000000

  extern const struct nla_policy nda_policy[];

  
  static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
  {
  	return *(const u16 *)n->primary_key == *(const u16 *)pkey;
  }
  
  static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
  {
  	return *(const u32 *)n->primary_key == *(const u32 *)pkey;
  }
  
  static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
  {
  	const u32 *n32 = (const u32 *)n->primary_key;
  	const u32 *p32 = pkey;
  
  	return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
  		(n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
  }
  
  static inline struct neighbour *___neigh_lookup_noref(
  	struct neigh_table *tbl,
  	bool (*key_eq)(const struct neighbour *n, const void *pkey),
  	__u32 (*hash)(const void *pkey,
  		      const struct net_device *dev,
  		      __u32 *hash_rnd),
  	const void *pkey,
  	struct net_device *dev)
  {
  	struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
  	struct neighbour *n;
  	u32 hash_val;
  
  	hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
  	for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
  	     n != NULL;
  	     n = rcu_dereference_bh(n->next)) {
  		if (n->dev == dev && key_eq(n, pkey))
  			return n;
  	}
  
  	return NULL;
  }
  
  static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
  						     const void *pkey,
  						     struct net_device *dev)
  {
  	return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
  }

  void neigh_table_init(int index, struct neigh_table *tbl);
  int neigh_table_clear(int index, 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,
  		 u32 nlmsg_pid);

  void __neigh_set_probe_once(struct neighbour *neigh);

  bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);

  void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
  int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);

  int neigh_carrier_down(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_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 *));

  int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);

  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 *buffer, size_t *lenp, loff_t *ppos);

  int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,

  				void *buffer,

  				size_t *lenp, loff_t *ppos);
  int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,

  				   void *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)
  {

  	refcount_dec(&parms->refcnt);

  }

  static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
  {

  	refcount_inc(&parms->refcnt);

  	return parms;
  }
  
  /*
   *	Neighbour references
   */
  
  static inline void neigh_release(struct neighbour *neigh)
  {

  	if (refcount_dec_and_test(&neigh->refcnt))

  		neigh_destroy(neigh);
  }
  
  static inline struct neighbour * neigh_clone(struct neighbour *neigh)
  {
  	if (neigh)

  		refcount_inc(&neigh->refcnt);

  	return neigh;
  }

  #define neigh_hold(n)	refcount_inc(&(n)->refcnt)

  static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
  {

  	unsigned long now = jiffies;

  	if (READ_ONCE(neigh->used) != now)
  		WRITE_ONCE(neigh->used, now);

  	if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE)))
  		return __neigh_event_send(neigh, skb);
  	return 0;
  }

  #if IS_ENABLED(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 hh_alen = 0;

  	unsigned int seq;

  	unsigned int hh_len;

  
  	do {

  		seq = read_seqbegin(&hh->hh_lock);

  		hh_len = READ_ONCE(hh->hh_len);

  		if (likely(hh_len <= HH_DATA_MOD)) {

  			hh_alen = HH_DATA_MOD;
  
  			/* skb_push() would proceed silently if we have room for
  			 * the unaligned size but not for the aligned size:
  			 * check headroom explicitly.
  			 */
  			if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
  				/* this is inlined by gcc */
  				memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
  				       HH_DATA_MOD);
  			}

  		} else {

  			hh_alen = HH_DATA_ALIGN(hh_len);

  			if (likely(skb_headroom(skb) >= hh_alen)) {
  				memcpy(skb->data - hh_alen, hh->hh_data,
  				       hh_alen);
  			}

  		}

  	} while (read_seqretry(&hh->hh_lock, seq));

  	if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
  		kfree_skb(skb);
  		return NET_XMIT_DROP;
  	}
  
  	__skb_push(skb, hh_len);

  	return dev_queue_xmit(skb);

  }

  static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
  			       bool skip_cache)

  {
  	const struct hh_cache *hh = &n->hh;

  	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len && !skip_cache)

  		return neigh_hh_output(hh, skb);
  	else
  		return n->output(n, 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));
  }

  static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
  					  int *notify)
  {
  	u8 ndm_flags = 0;
  
  	ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
  	if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
  		if (ndm_flags & NTF_ROUTER)
  			neigh->flags |= NTF_ROUTER;
  		else
  			neigh->flags &= ~NTF_ROUTER;
  		*notify = 1;
  	}
  }

  #endif