1  /* SPDX-License-Identifier: GPL-2.0 */
2  #ifndef _NET_NEIGHBOUR_H
3  #define _NET_NEIGHBOUR_H
4  
5  #include <linux/neighbour.h>
6  
7  /*
8   *	Generic neighbour manipulation
9   *
10   *	Authors:
11   *	Pedro Roque		<roque@di.fc.ul.pt>
12   *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
13   *
14   * 	Changes:
15   *
16   *	Harald Welte:		<laforge@gnumonks.org>
17   *		- Add neighbour cache statistics like rtstat
18   */
19  
20  #include <linux/atomic.h>
21  #include <linux/refcount.h>
22  #include <linux/netdevice.h>
23  #include <linux/skbuff.h>
24  #include <linux/rcupdate.h>
25  #include <linux/seq_file.h>
26  #include <linux/bitmap.h>
27  
28  #include <linux/err.h>
29  #include <linux/sysctl.h>
30  #include <linux/workqueue.h>
31  #include <net/rtnetlink.h>
32  
33  /*
34   * NUD stands for "neighbor unreachability detection"
35   */
36  
37  #define NUD_IN_TIMER	(NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
38  #define NUD_VALID	(NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
39  #define NUD_CONNECTED	(NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
40  
41  struct neighbour;
42  
43  enum {
44  	NEIGH_VAR_MCAST_PROBES,
45  	NEIGH_VAR_UCAST_PROBES,
46  	NEIGH_VAR_APP_PROBES,
47  	NEIGH_VAR_MCAST_REPROBES,
48  	NEIGH_VAR_RETRANS_TIME,
49  	NEIGH_VAR_BASE_REACHABLE_TIME,
50  	NEIGH_VAR_DELAY_PROBE_TIME,
51  	NEIGH_VAR_INTERVAL_PROBE_TIME_MS,
52  	NEIGH_VAR_GC_STALETIME,
53  	NEIGH_VAR_QUEUE_LEN_BYTES,
54  	NEIGH_VAR_PROXY_QLEN,
55  	NEIGH_VAR_ANYCAST_DELAY,
56  	NEIGH_VAR_PROXY_DELAY,
57  	NEIGH_VAR_LOCKTIME,
58  #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
59  	/* Following are used as a second way to access one of the above */
60  	NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
61  	NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
62  	NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
63  	/* Following are used by "default" only */
64  	NEIGH_VAR_GC_INTERVAL,
65  	NEIGH_VAR_GC_THRESH1,
66  	NEIGH_VAR_GC_THRESH2,
67  	NEIGH_VAR_GC_THRESH3,
68  	NEIGH_VAR_MAX
69  };
70  
71  struct neigh_parms {
72  	possible_net_t net;
73  	struct net_device *dev;
74  	netdevice_tracker dev_tracker;
75  	struct list_head list;
76  	int	(*neigh_setup)(struct neighbour *);
77  	struct neigh_table *tbl;
78  
79  	void	*sysctl_table;
80  
81  	int dead;
82  	refcount_t refcnt;
83  	struct rcu_head rcu_head;
84  
85  	int	reachable_time;
86  	u32	qlen;
87  	int	data[NEIGH_VAR_DATA_MAX];
88  	DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
89  };
90  
neigh_var_set(struct neigh_parms * p,int index,int val)91  static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
92  {
93  	set_bit(index, p->data_state);
94  	p->data[index] = val;
95  }
96  
97  #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
98  
99  /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
100   * In other cases, NEIGH_VAR_SET should be used.
101   */
102  #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
103  #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
104  
neigh_parms_data_state_setall(struct neigh_parms * p)105  static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
106  {
107  	bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
108  }
109  
neigh_parms_data_state_cleanall(struct neigh_parms * p)110  static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
111  {
112  	bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
113  }
114  
115  struct neigh_statistics {
116  	unsigned long allocs;		/* number of allocated neighs */
117  	unsigned long destroys;		/* number of destroyed neighs */
118  	unsigned long hash_grows;	/* number of hash resizes */
119  
120  	unsigned long res_failed;	/* number of failed resolutions */
121  
122  	unsigned long lookups;		/* number of lookups */
123  	unsigned long hits;		/* number of hits (among lookups) */
124  
125  	unsigned long rcv_probes_mcast;	/* number of received mcast ipv6 */
126  	unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
127  
128  	unsigned long periodic_gc_runs;	/* number of periodic GC runs */
129  	unsigned long forced_gc_runs;	/* number of forced GC runs */
130  
131  	unsigned long unres_discards;	/* number of unresolved drops */
132  	unsigned long table_fulls;      /* times even gc couldn't help */
133  };
134  
135  #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
136  
137  struct neighbour {
138  	struct neighbour __rcu	*next;
139  	struct neigh_table	*tbl;
140  	struct neigh_parms	*parms;
141  	unsigned long		confirmed;
142  	unsigned long		updated;
143  	rwlock_t		lock;
144  	refcount_t		refcnt;
145  	unsigned int		arp_queue_len_bytes;
146  	struct sk_buff_head	arp_queue;
147  	struct timer_list	timer;
148  	unsigned long		used;
149  	atomic_t		probes;
150  	u8			nud_state;
151  	u8			type;
152  	u8			dead;
153  	u8			protocol;
154  	u32			flags;
155  	seqlock_t		ha_lock;
156  	unsigned char		ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);
157  	struct hh_cache		hh;
158  	int			(*output)(struct neighbour *, struct sk_buff *);
159  	const struct neigh_ops	*ops;
160  	struct list_head	gc_list;
161  	struct list_head	managed_list;
162  	struct rcu_head		rcu;
163  	struct net_device	*dev;
164  	netdevice_tracker	dev_tracker;
165  	u8			primary_key[0];
166  } __randomize_layout;
167  
168  struct neigh_ops {
169  	int			family;
170  	void			(*solicit)(struct neighbour *, struct sk_buff *);
171  	void			(*error_report)(struct neighbour *, struct sk_buff *);
172  	int			(*output)(struct neighbour *, struct sk_buff *);
173  	int			(*connected_output)(struct neighbour *, struct sk_buff *);
174  };
175  
176  struct pneigh_entry {
177  	struct pneigh_entry	*next;
178  	possible_net_t		net;
179  	struct net_device	*dev;
180  	netdevice_tracker	dev_tracker;
181  	u32			flags;
182  	u8			protocol;
183  	u8			key[];
184  };
185  
186  /*
187   *	neighbour table manipulation
188   */
189  
190  #define NEIGH_NUM_HASH_RND	4
191  
192  struct neigh_hash_table {
193  	struct neighbour __rcu	**hash_buckets;
194  	unsigned int		hash_shift;
195  	__u32			hash_rnd[NEIGH_NUM_HASH_RND];
196  	struct rcu_head		rcu;
197  };
198  
199  
200  struct neigh_table {
201  	int			family;
202  	unsigned int		entry_size;
203  	unsigned int		key_len;
204  	__be16			protocol;
205  	__u32			(*hash)(const void *pkey,
206  					const struct net_device *dev,
207  					__u32 *hash_rnd);
208  	bool			(*key_eq)(const struct neighbour *, const void *pkey);
209  	int			(*constructor)(struct neighbour *);
210  	int			(*pconstructor)(struct pneigh_entry *);
211  	void			(*pdestructor)(struct pneigh_entry *);
212  	void			(*proxy_redo)(struct sk_buff *skb);
213  	int			(*is_multicast)(const void *pkey);
214  	bool			(*allow_add)(const struct net_device *dev,
215  					     struct netlink_ext_ack *extack);
216  	char			*id;
217  	struct neigh_parms	parms;
218  	struct list_head	parms_list;
219  	int			gc_interval;
220  	int			gc_thresh1;
221  	int			gc_thresh2;
222  	int			gc_thresh3;
223  	unsigned long		last_flush;
224  	struct delayed_work	gc_work;
225  	struct delayed_work	managed_work;
226  	struct timer_list 	proxy_timer;
227  	struct sk_buff_head	proxy_queue;
228  	atomic_t		entries;
229  	atomic_t		gc_entries;
230  	struct list_head	gc_list;
231  	struct list_head	managed_list;
232  	rwlock_t		lock;
233  	unsigned long		last_rand;
234  	struct neigh_statistics	__percpu *stats;
235  	struct neigh_hash_table __rcu *nht;
236  	struct pneigh_entry	**phash_buckets;
237  };
238  
239  enum {
240  	NEIGH_ARP_TABLE = 0,
241  	NEIGH_ND_TABLE = 1,
242  	NEIGH_DN_TABLE = 2,
243  	NEIGH_NR_TABLES,
244  	NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
245  };
246  
neigh_parms_family(struct neigh_parms * p)247  static inline int neigh_parms_family(struct neigh_parms *p)
248  {
249  	return p->tbl->family;
250  }
251  
252  #define NEIGH_PRIV_ALIGN	sizeof(long long)
253  #define NEIGH_ENTRY_SIZE(size)	ALIGN((size), NEIGH_PRIV_ALIGN)
254  
neighbour_priv(const struct neighbour * n)255  static inline void *neighbour_priv(const struct neighbour *n)
256  {
257  	return (char *)n + n->tbl->entry_size;
258  }
259  
260  /* flags for neigh_update() */
261  #define NEIGH_UPDATE_F_OVERRIDE			BIT(0)
262  #define NEIGH_UPDATE_F_WEAK_OVERRIDE		BIT(1)
263  #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER	BIT(2)
264  #define NEIGH_UPDATE_F_USE			BIT(3)
265  #define NEIGH_UPDATE_F_MANAGED			BIT(4)
266  #define NEIGH_UPDATE_F_EXT_LEARNED		BIT(5)
267  #define NEIGH_UPDATE_F_ISROUTER			BIT(6)
268  #define NEIGH_UPDATE_F_ADMIN			BIT(7)
269  
270  /* In-kernel representation for NDA_FLAGS_EXT flags: */
271  #define NTF_OLD_MASK		0xff
272  #define NTF_EXT_SHIFT		8
273  #define NTF_EXT_MASK		(NTF_EXT_MANAGED)
274  
275  #define NTF_MANAGED		(NTF_EXT_MANAGED << NTF_EXT_SHIFT)
276  
277  extern const struct nla_policy nda_policy[];
278  
neigh_key_eq32(const struct neighbour * n,const void * pkey)279  static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
280  {
281  	return *(const u32 *)n->primary_key == *(const u32 *)pkey;
282  }
283  
neigh_key_eq128(const struct neighbour * n,const void * pkey)284  static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
285  {
286  	const u32 *n32 = (const u32 *)n->primary_key;
287  	const u32 *p32 = pkey;
288  
289  	return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
290  		(n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
291  }
292  
___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)293  static inline struct neighbour *___neigh_lookup_noref(
294  	struct neigh_table *tbl,
295  	bool (*key_eq)(const struct neighbour *n, const void *pkey),
296  	__u32 (*hash)(const void *pkey,
297  		      const struct net_device *dev,
298  		      __u32 *hash_rnd),
299  	const void *pkey,
300  	struct net_device *dev)
301  {
302  	struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
303  	struct neighbour *n;
304  	u32 hash_val;
305  
306  	hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
307  	for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
308  	     n != NULL;
309  	     n = rcu_dereference_bh(n->next)) {
310  		if (n->dev == dev && key_eq(n, pkey))
311  			return n;
312  	}
313  
314  	return NULL;
315  }
316  
__neigh_lookup_noref(struct neigh_table * tbl,const void * pkey,struct net_device * dev)317  static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
318  						     const void *pkey,
319  						     struct net_device *dev)
320  {
321  	return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
322  }
323  
neigh_confirm(struct neighbour * n)324  static inline void neigh_confirm(struct neighbour *n)
325  {
326  	if (n) {
327  		unsigned long now = jiffies;
328  
329  		/* avoid dirtying neighbour */
330  		if (READ_ONCE(n->confirmed) != now)
331  			WRITE_ONCE(n->confirmed, now);
332  	}
333  }
334  
335  void neigh_table_init(int index, struct neigh_table *tbl);
336  int neigh_table_clear(int index, struct neigh_table *tbl);
337  struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
338  			       struct net_device *dev);
339  struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
340  				     const void *pkey);
341  struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
342  				 struct net_device *dev, bool want_ref);
neigh_create(struct neigh_table * tbl,const void * pkey,struct net_device * dev)343  static inline struct neighbour *neigh_create(struct neigh_table *tbl,
344  					     const void *pkey,
345  					     struct net_device *dev)
346  {
347  	return __neigh_create(tbl, pkey, dev, true);
348  }
349  void neigh_destroy(struct neighbour *neigh);
350  int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
351  		       const bool immediate_ok);
352  int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
353  		 u32 nlmsg_pid);
354  void __neigh_set_probe_once(struct neighbour *neigh);
355  bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
356  void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
357  int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
358  int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
359  int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
360  int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
361  int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
362  struct neighbour *neigh_event_ns(struct neigh_table *tbl,
363  						u8 *lladdr, void *saddr,
364  						struct net_device *dev);
365  
366  struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
367  				      struct neigh_table *tbl);
368  void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
369  
370  static inline
neigh_parms_net(const struct neigh_parms * parms)371  struct net *neigh_parms_net(const struct neigh_parms *parms)
372  {
373  	return read_pnet(&parms->net);
374  }
375  
376  unsigned long neigh_rand_reach_time(unsigned long base);
377  
378  void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
379  		    struct sk_buff *skb);
380  struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
381  				   const void *key, struct net_device *dev,
382  				   int creat);
383  struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
384  				     const void *key, struct net_device *dev);
385  int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
386  		  struct net_device *dev);
387  
pneigh_net(const struct pneigh_entry * pneigh)388  static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
389  {
390  	return read_pnet(&pneigh->net);
391  }
392  
393  void neigh_app_ns(struct neighbour *n);
394  void neigh_for_each(struct neigh_table *tbl,
395  		    void (*cb)(struct neighbour *, void *), void *cookie);
396  void __neigh_for_each_release(struct neigh_table *tbl,
397  			      int (*cb)(struct neighbour *));
398  int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
399  void pneigh_for_each(struct neigh_table *tbl,
400  		     void (*cb)(struct pneigh_entry *));
401  
402  struct neigh_seq_state {
403  	struct seq_net_private p;
404  	struct neigh_table *tbl;
405  	struct neigh_hash_table *nht;
406  	void *(*neigh_sub_iter)(struct neigh_seq_state *state,
407  				struct neighbour *n, loff_t *pos);
408  	unsigned int bucket;
409  	unsigned int flags;
410  #define NEIGH_SEQ_NEIGH_ONLY	0x00000001
411  #define NEIGH_SEQ_IS_PNEIGH	0x00000002
412  #define NEIGH_SEQ_SKIP_NOARP	0x00000004
413  };
414  void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
415  		      unsigned int);
416  void *neigh_seq_next(struct seq_file *, void *, loff_t *);
417  void neigh_seq_stop(struct seq_file *, void *);
418  
419  int neigh_proc_dointvec(struct ctl_table *ctl, int write,
420  			void *buffer, size_t *lenp, loff_t *ppos);
421  int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
422  				void *buffer,
423  				size_t *lenp, loff_t *ppos);
424  int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
425  				   void *buffer, size_t *lenp, loff_t *ppos);
426  
427  int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
428  			  proc_handler *proc_handler);
429  void neigh_sysctl_unregister(struct neigh_parms *p);
430  
__neigh_parms_put(struct neigh_parms * parms)431  static inline void __neigh_parms_put(struct neigh_parms *parms)
432  {
433  	refcount_dec(&parms->refcnt);
434  }
435  
neigh_parms_clone(struct neigh_parms * parms)436  static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
437  {
438  	refcount_inc(&parms->refcnt);
439  	return parms;
440  }
441  
442  /*
443   *	Neighbour references
444   */
445  
neigh_release(struct neighbour * neigh)446  static inline void neigh_release(struct neighbour *neigh)
447  {
448  	if (refcount_dec_and_test(&neigh->refcnt))
449  		neigh_destroy(neigh);
450  }
451  
neigh_clone(struct neighbour * neigh)452  static inline struct neighbour * neigh_clone(struct neighbour *neigh)
453  {
454  	if (neigh)
455  		refcount_inc(&neigh->refcnt);
456  	return neigh;
457  }
458  
459  #define neigh_hold(n)	refcount_inc(&(n)->refcnt)
460  
neigh_event_send_probe(struct neighbour * neigh,struct sk_buff * skb,const bool immediate_ok)461  static __always_inline int neigh_event_send_probe(struct neighbour *neigh,
462  						  struct sk_buff *skb,
463  						  const bool immediate_ok)
464  {
465  	unsigned long now = jiffies;
466  
467  	if (READ_ONCE(neigh->used) != now)
468  		WRITE_ONCE(neigh->used, now);
469  	if (!(neigh->nud_state & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE)))
470  		return __neigh_event_send(neigh, skb, immediate_ok);
471  	return 0;
472  }
473  
neigh_event_send(struct neighbour * neigh,struct sk_buff * skb)474  static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
475  {
476  	return neigh_event_send_probe(neigh, skb, true);
477  }
478  
479  #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
neigh_hh_bridge(struct hh_cache * hh,struct sk_buff * skb)480  static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
481  {
482  	unsigned int seq, hh_alen;
483  
484  	do {
485  		seq = read_seqbegin(&hh->hh_lock);
486  		hh_alen = HH_DATA_ALIGN(ETH_HLEN);
487  		memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
488  	} while (read_seqretry(&hh->hh_lock, seq));
489  	return 0;
490  }
491  #endif
492  
neigh_hh_output(const struct hh_cache * hh,struct sk_buff * skb)493  static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
494  {
495  	unsigned int hh_alen = 0;
496  	unsigned int seq;
497  	unsigned int hh_len;
498  
499  	do {
500  		seq = read_seqbegin(&hh->hh_lock);
501  		hh_len = READ_ONCE(hh->hh_len);
502  		if (likely(hh_len <= HH_DATA_MOD)) {
503  			hh_alen = HH_DATA_MOD;
504  
505  			/* skb_push() would proceed silently if we have room for
506  			 * the unaligned size but not for the aligned size:
507  			 * check headroom explicitly.
508  			 */
509  			if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
510  				/* this is inlined by gcc */
511  				memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
512  				       HH_DATA_MOD);
513  			}
514  		} else {
515  			hh_alen = HH_DATA_ALIGN(hh_len);
516  
517  			if (likely(skb_headroom(skb) >= hh_alen)) {
518  				memcpy(skb->data - hh_alen, hh->hh_data,
519  				       hh_alen);
520  			}
521  		}
522  	} while (read_seqretry(&hh->hh_lock, seq));
523  
524  	if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
525  		kfree_skb(skb);
526  		return NET_XMIT_DROP;
527  	}
528  
529  	__skb_push(skb, hh_len);
530  	return dev_queue_xmit(skb);
531  }
532  
neigh_output(struct neighbour * n,struct sk_buff * skb,bool skip_cache)533  static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
534  			       bool skip_cache)
535  {
536  	const struct hh_cache *hh = &n->hh;
537  
538  	/* n->nud_state and hh->hh_len could be changed under us.
539  	 * neigh_hh_output() is taking care of the race later.
540  	 */
541  	if (!skip_cache &&
542  	    (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
543  	    READ_ONCE(hh->hh_len))
544  		return neigh_hh_output(hh, skb);
545  
546  	return n->output(n, skb);
547  }
548  
549  static inline struct neighbour *
__neigh_lookup(struct neigh_table * tbl,const void * pkey,struct net_device * dev,int creat)550  __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
551  {
552  	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
553  
554  	if (n || !creat)
555  		return n;
556  
557  	n = neigh_create(tbl, pkey, dev);
558  	return IS_ERR(n) ? NULL : n;
559  }
560  
561  static inline struct neighbour *
__neigh_lookup_errno(struct neigh_table * tbl,const void * pkey,struct net_device * dev)562  __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
563    struct net_device *dev)
564  {
565  	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
566  
567  	if (n)
568  		return n;
569  
570  	return neigh_create(tbl, pkey, dev);
571  }
572  
573  struct neighbour_cb {
574  	unsigned long sched_next;
575  	unsigned int flags;
576  };
577  
578  #define LOCALLY_ENQUEUED 0x1
579  
580  #define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
581  
neigh_ha_snapshot(char * dst,const struct neighbour * n,const struct net_device * dev)582  static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
583  				     const struct net_device *dev)
584  {
585  	unsigned int seq;
586  
587  	do {
588  		seq = read_seqbegin(&n->ha_lock);
589  		memcpy(dst, n->ha, dev->addr_len);
590  	} while (read_seqretry(&n->ha_lock, seq));
591  }
592  
neigh_update_is_router(struct neighbour * neigh,u32 flags,int * notify)593  static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
594  					  int *notify)
595  {
596  	u8 ndm_flags = 0;
597  
598  	ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
599  	if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
600  		if (ndm_flags & NTF_ROUTER)
601  			neigh->flags |= NTF_ROUTER;
602  		else
603  			neigh->flags &= ~NTF_ROUTER;
604  		*notify = 1;
605  	}
606  }
607  #endif
608