xref: /linux/include/net/neighbour.h (revision 8be4d31cb8aaeea27bde4b7ddb26e28a89062ebf)
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 #include <net/neighbour_tables.h>
33 
34 /*
35  * NUD stands for "neighbor unreachability detection"
36  */
37 
38 #define NUD_IN_TIMER	(NUD_INCOMPLETE|NUD_REACHABLE|NUD_DELAY|NUD_PROBE)
39 #define NUD_VALID	(NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE|NUD_PROBE|NUD_STALE|NUD_DELAY)
40 #define NUD_CONNECTED	(NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE)
41 
42 struct neighbour;
43 
44 enum {
45 	NEIGH_VAR_MCAST_PROBES,
46 	NEIGH_VAR_UCAST_PROBES,
47 	NEIGH_VAR_APP_PROBES,
48 	NEIGH_VAR_MCAST_REPROBES,
49 	NEIGH_VAR_RETRANS_TIME,
50 	NEIGH_VAR_BASE_REACHABLE_TIME,
51 	NEIGH_VAR_DELAY_PROBE_TIME,
52 	NEIGH_VAR_INTERVAL_PROBE_TIME_MS,
53 	NEIGH_VAR_GC_STALETIME,
54 	NEIGH_VAR_QUEUE_LEN_BYTES,
55 	NEIGH_VAR_PROXY_QLEN,
56 	NEIGH_VAR_ANYCAST_DELAY,
57 	NEIGH_VAR_PROXY_DELAY,
58 	NEIGH_VAR_LOCKTIME,
59 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
60 	/* Following are used as a second way to access one of the above */
61 	NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
62 	NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
63 	NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
64 	/* Following are used by "default" only */
65 	NEIGH_VAR_GC_INTERVAL,
66 	NEIGH_VAR_GC_THRESH1,
67 	NEIGH_VAR_GC_THRESH2,
68 	NEIGH_VAR_GC_THRESH3,
69 	NEIGH_VAR_MAX
70 };
71 
72 struct neigh_parms {
73 	possible_net_t net;
74 	struct net_device *dev;
75 	netdevice_tracker dev_tracker;
76 	struct list_head list;
77 	int	(*neigh_setup)(struct neighbour *);
78 	struct neigh_table *tbl;
79 
80 	void	*sysctl_table;
81 
82 	int dead;
83 	refcount_t refcnt;
84 	struct rcu_head rcu_head;
85 
86 	int	reachable_time;
87 	u32	qlen;
88 	int	data[NEIGH_VAR_DATA_MAX];
89 	DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
90 };
91 
neigh_var_set(struct neigh_parms * p,int index,int val)92 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
93 {
94 	set_bit(index, p->data_state);
95 	p->data[index] = val;
96 }
97 
98 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
99 
100 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
101  * In other cases, NEIGH_VAR_SET should be used.
102  */
103 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
104 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
105 
neigh_parms_data_state_setall(struct neigh_parms * p)106 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
107 {
108 	bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
109 }
110 
neigh_parms_data_state_cleanall(struct neigh_parms * p)111 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
112 {
113 	bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
114 }
115 
116 struct neigh_statistics {
117 	unsigned long allocs;		/* number of allocated neighs */
118 	unsigned long destroys;		/* number of destroyed neighs */
119 	unsigned long hash_grows;	/* number of hash resizes */
120 
121 	unsigned long res_failed;	/* number of failed resolutions */
122 
123 	unsigned long lookups;		/* number of lookups */
124 	unsigned long hits;		/* number of hits (among lookups) */
125 
126 	unsigned long rcv_probes_mcast;	/* number of received mcast ipv6 */
127 	unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
128 
129 	unsigned long periodic_gc_runs;	/* number of periodic GC runs */
130 	unsigned long forced_gc_runs;	/* number of forced GC runs */
131 
132 	unsigned long unres_discards;	/* number of unresolved drops */
133 	unsigned long table_fulls;      /* times even gc couldn't help */
134 };
135 
136 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
137 
138 struct neighbour {
139 	struct hlist_node	hash;
140 	struct hlist_node	dev_list;
141 	struct neigh_table	*tbl;
142 	struct neigh_parms	*parms;
143 	unsigned long		confirmed;
144 	unsigned long		updated;
145 	rwlock_t		lock;
146 	refcount_t		refcnt;
147 	unsigned int		arp_queue_len_bytes;
148 	struct sk_buff_head	arp_queue;
149 	struct timer_list	timer;
150 	unsigned long		used;
151 	atomic_t		probes;
152 	u8			nud_state;
153 	u8			type;
154 	u8			dead;
155 	u8			protocol;
156 	u32			flags;
157 	seqlock_t		ha_lock;
158 	unsigned char		ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);
159 	struct hh_cache		hh;
160 	int			(*output)(struct neighbour *, struct sk_buff *);
161 	const struct neigh_ops	*ops;
162 	struct list_head	gc_list;
163 	struct list_head	managed_list;
164 	struct rcu_head		rcu;
165 	struct net_device	*dev;
166 	netdevice_tracker	dev_tracker;
167 	u8			primary_key[];
168 } __randomize_layout;
169 
170 struct neigh_ops {
171 	int			family;
172 	void			(*solicit)(struct neighbour *, struct sk_buff *);
173 	void			(*error_report)(struct neighbour *, struct sk_buff *);
174 	int			(*output)(struct neighbour *, struct sk_buff *);
175 	int			(*connected_output)(struct neighbour *, struct sk_buff *);
176 };
177 
178 struct pneigh_entry {
179 	struct pneigh_entry	__rcu *next;
180 	possible_net_t		net;
181 	struct net_device	*dev;
182 	netdevice_tracker	dev_tracker;
183 	union {
184 		struct list_head	free_node;
185 		struct rcu_head		rcu;
186 	};
187 	u32			flags;
188 	u8			protocol;
189 	bool			permanent;
190 	u32			key[];
191 };
192 
193 /*
194  *	neighbour table manipulation
195  */
196 
197 #define NEIGH_NUM_HASH_RND	4
198 
199 struct neigh_hash_table {
200 	struct hlist_head	*hash_heads;
201 	unsigned int		hash_shift;
202 	__u32			hash_rnd[NEIGH_NUM_HASH_RND];
203 	struct rcu_head		rcu;
204 };
205 
206 
207 struct neigh_table {
208 	int			family;
209 	unsigned int		entry_size;
210 	unsigned int		key_len;
211 	__be16			protocol;
212 	__u32			(*hash)(const void *pkey,
213 					const struct net_device *dev,
214 					__u32 *hash_rnd);
215 	bool			(*key_eq)(const struct neighbour *, const void *pkey);
216 	int			(*constructor)(struct neighbour *);
217 	int			(*pconstructor)(struct pneigh_entry *);
218 	void			(*pdestructor)(struct pneigh_entry *);
219 	void			(*proxy_redo)(struct sk_buff *skb);
220 	int			(*is_multicast)(const void *pkey);
221 	bool			(*allow_add)(const struct net_device *dev,
222 					     struct netlink_ext_ack *extack);
223 	char			*id;
224 	struct neigh_parms	parms;
225 	struct list_head	parms_list;
226 	int			gc_interval;
227 	int			gc_thresh1;
228 	int			gc_thresh2;
229 	int			gc_thresh3;
230 	unsigned long		last_flush;
231 	struct delayed_work	gc_work;
232 	struct delayed_work	managed_work;
233 	struct timer_list 	proxy_timer;
234 	struct sk_buff_head	proxy_queue;
235 	atomic_t		entries;
236 	atomic_t		gc_entries;
237 	struct list_head	gc_list;
238 	struct list_head	managed_list;
239 	rwlock_t		lock;
240 	unsigned long		last_rand;
241 	struct neigh_statistics	__percpu *stats;
242 	struct neigh_hash_table __rcu *nht;
243 	struct mutex		phash_lock;
244 	struct pneigh_entry	__rcu **phash_buckets;
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 #define NEIGH_UPDATE_F_EXT_VALIDATED		BIT(8)
270 
271 /* In-kernel representation for NDA_FLAGS_EXT flags: */
272 #define NTF_OLD_MASK		0xff
273 #define NTF_EXT_SHIFT		8
274 #define NTF_EXT_MASK		(NTF_EXT_MANAGED | NTF_EXT_EXT_VALIDATED)
275 
276 #define NTF_MANAGED		(NTF_EXT_MANAGED << NTF_EXT_SHIFT)
277 #define NTF_EXT_VALIDATED	(NTF_EXT_EXT_VALIDATED << NTF_EXT_SHIFT)
278 
279 extern const struct nla_policy nda_policy[];
280 
281 #define neigh_for_each_in_bucket(pos, head) hlist_for_each_entry(pos, head, hash)
282 #define neigh_for_each_in_bucket_rcu(pos, head) \
283 	hlist_for_each_entry_rcu(pos, head, hash)
284 #define neigh_for_each_in_bucket_safe(pos, tmp, head) \
285 	hlist_for_each_entry_safe(pos, tmp, head, hash)
286 
neigh_key_eq32(const struct neighbour * n,const void * pkey)287 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
288 {
289 	return *(const u32 *)n->primary_key == *(const u32 *)pkey;
290 }
291 
neigh_key_eq128(const struct neighbour * n,const void * pkey)292 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
293 {
294 	const u32 *n32 = (const u32 *)n->primary_key;
295 	const u32 *p32 = pkey;
296 
297 	return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
298 		(n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
299 }
300 
___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)301 static inline struct neighbour *___neigh_lookup_noref(
302 	struct neigh_table *tbl,
303 	bool (*key_eq)(const struct neighbour *n, const void *pkey),
304 	__u32 (*hash)(const void *pkey,
305 		      const struct net_device *dev,
306 		      __u32 *hash_rnd),
307 	const void *pkey,
308 	struct net_device *dev)
309 {
310 	struct neigh_hash_table *nht = rcu_dereference(tbl->nht);
311 	struct neighbour *n;
312 	u32 hash_val;
313 
314 	hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
315 	neigh_for_each_in_bucket_rcu(n, &nht->hash_heads[hash_val])
316 		if (n->dev == dev && key_eq(n, pkey))
317 			return n;
318 
319 	return NULL;
320 }
321 
__neigh_lookup_noref(struct neigh_table * tbl,const void * pkey,struct net_device * dev)322 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
323 						     const void *pkey,
324 						     struct net_device *dev)
325 {
326 	return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
327 }
328 
neigh_confirm(struct neighbour * n)329 static inline void neigh_confirm(struct neighbour *n)
330 {
331 	if (n) {
332 		unsigned long now = jiffies;
333 
334 		/* avoid dirtying neighbour */
335 		if (READ_ONCE(n->confirmed) != now)
336 			WRITE_ONCE(n->confirmed, now);
337 	}
338 }
339 
340 void neigh_table_init(int index, struct neigh_table *tbl);
341 int neigh_table_clear(int index, struct neigh_table *tbl);
342 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
343 			       struct net_device *dev);
344 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
345 				 struct net_device *dev, bool want_ref);
neigh_create(struct neigh_table * tbl,const void * pkey,struct net_device * dev)346 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
347 					     const void *pkey,
348 					     struct net_device *dev)
349 {
350 	return __neigh_create(tbl, pkey, dev, true);
351 }
352 void neigh_destroy(struct neighbour *neigh);
353 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
354 		       const bool immediate_ok);
355 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
356 		 u32 nlmsg_pid);
357 void __neigh_set_probe_once(struct neighbour *neigh);
358 bool neigh_remove_one(struct neighbour *ndel);
359 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
360 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
361 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
362 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
363 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
364 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
365 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
366 						u8 *lladdr, void *saddr,
367 						struct net_device *dev);
368 
369 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
370 				      struct neigh_table *tbl);
371 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
372 
373 static inline
neigh_parms_net(const struct neigh_parms * parms)374 struct net *neigh_parms_net(const struct neigh_parms *parms)
375 {
376 	return read_pnet(&parms->net);
377 }
378 
379 unsigned long neigh_rand_reach_time(unsigned long base);
380 
381 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
382 		    struct sk_buff *skb);
383 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
384 				   const void *key, struct net_device *dev);
385 int pneigh_create(struct neigh_table *tbl, struct net *net, const void *key,
386 		  struct net_device *dev, u32 flags, u8 protocol,
387 		  bool permanent);
388 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
389 		  struct net_device *dev);
390 
pneigh_net(const struct pneigh_entry * pneigh)391 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
392 {
393 	return read_pnet(&pneigh->net);
394 }
395 
396 void neigh_app_ns(struct neighbour *n);
397 void neigh_for_each(struct neigh_table *tbl,
398 		    void (*cb)(struct neighbour *, void *), void *cookie);
399 void __neigh_for_each_release(struct neigh_table *tbl,
400 			      int (*cb)(struct neighbour *));
401 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
402 
403 struct neigh_seq_state {
404 	struct seq_net_private p;
405 	struct neigh_table *tbl;
406 	struct neigh_hash_table *nht;
407 	void *(*neigh_sub_iter)(struct neigh_seq_state *state,
408 				struct neighbour *n, loff_t *pos);
409 	unsigned int bucket;
410 	unsigned int flags;
411 #define NEIGH_SEQ_NEIGH_ONLY	0x00000001
412 #define NEIGH_SEQ_IS_PNEIGH	0x00000002
413 #define NEIGH_SEQ_SKIP_NOARP	0x00000004
414 };
415 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
416 		      unsigned int);
417 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
418 void neigh_seq_stop(struct seq_file *, void *);
419 
420 int neigh_proc_dointvec(const struct ctl_table *ctl, int write,
421 			void *buffer, size_t *lenp, loff_t *ppos);
422 int neigh_proc_dointvec_jiffies(const struct ctl_table *ctl, int write,
423 				void *buffer,
424 				size_t *lenp, loff_t *ppos);
425 int neigh_proc_dointvec_ms_jiffies(const struct ctl_table *ctl, int write,
426 				   void *buffer, size_t *lenp, loff_t *ppos);
427 
428 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
429 			  proc_handler *proc_handler);
430 void neigh_sysctl_unregister(struct neigh_parms *p);
431 
__neigh_parms_put(struct neigh_parms * parms)432 static inline void __neigh_parms_put(struct neigh_parms *parms)
433 {
434 	refcount_dec(&parms->refcnt);
435 }
436 
neigh_parms_clone(struct neigh_parms * parms)437 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
438 {
439 	refcount_inc(&parms->refcnt);
440 	return parms;
441 }
442 
443 /*
444  *	Neighbour references
445  */
446 
neigh_release(struct neighbour * neigh)447 static inline void neigh_release(struct neighbour *neigh)
448 {
449 	if (refcount_dec_and_test(&neigh->refcnt))
450 		neigh_destroy(neigh);
451 }
452 
neigh_clone(struct neighbour * neigh)453 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
454 {
455 	if (neigh)
456 		refcount_inc(&neigh->refcnt);
457 	return neigh;
458 }
459 
460 #define neigh_hold(n)	refcount_inc(&(n)->refcnt)
461 
neigh_event_send_probe(struct neighbour * neigh,struct sk_buff * skb,const bool immediate_ok)462 static __always_inline int neigh_event_send_probe(struct neighbour *neigh,
463 						  struct sk_buff *skb,
464 						  const bool immediate_ok)
465 {
466 	unsigned long now = jiffies;
467 
468 	if (READ_ONCE(neigh->used) != now)
469 		WRITE_ONCE(neigh->used, now);
470 	if (!(READ_ONCE(neigh->nud_state) & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE)))
471 		return __neigh_event_send(neigh, skb, immediate_ok);
472 	return 0;
473 }
474 
neigh_event_send(struct neighbour * neigh,struct sk_buff * skb)475 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
476 {
477 	return neigh_event_send_probe(neigh, skb, true);
478 }
479 
480 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
neigh_hh_bridge(struct hh_cache * hh,struct sk_buff * skb)481 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
482 {
483 	unsigned int seq, hh_alen;
484 
485 	do {
486 		seq = read_seqbegin(&hh->hh_lock);
487 		hh_alen = HH_DATA_ALIGN(ETH_HLEN);
488 		memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
489 	} while (read_seqretry(&hh->hh_lock, seq));
490 	return 0;
491 }
492 #endif
493 
neigh_hh_output(const struct hh_cache * hh,struct sk_buff * skb)494 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
495 {
496 	unsigned int hh_alen = 0;
497 	unsigned int seq;
498 	unsigned int hh_len;
499 
500 	do {
501 		seq = read_seqbegin(&hh->hh_lock);
502 		hh_len = READ_ONCE(hh->hh_len);
503 		if (likely(hh_len <= HH_DATA_MOD)) {
504 			hh_alen = HH_DATA_MOD;
505 
506 			/* skb_push() would proceed silently if we have room for
507 			 * the unaligned size but not for the aligned size:
508 			 * check headroom explicitly.
509 			 */
510 			if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
511 				/* this is inlined by gcc */
512 				memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
513 				       HH_DATA_MOD);
514 			}
515 		} else {
516 			hh_alen = HH_DATA_ALIGN(hh_len);
517 
518 			if (likely(skb_headroom(skb) >= hh_alen)) {
519 				memcpy(skb->data - hh_alen, hh->hh_data,
520 				       hh_alen);
521 			}
522 		}
523 	} while (read_seqretry(&hh->hh_lock, seq));
524 
525 	if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
526 		kfree_skb(skb);
527 		return NET_XMIT_DROP;
528 	}
529 
530 	__skb_push(skb, hh_len);
531 	return dev_queue_xmit(skb);
532 }
533 
neigh_output(struct neighbour * n,struct sk_buff * skb,bool skip_cache)534 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
535 			       bool skip_cache)
536 {
537 	const struct hh_cache *hh = &n->hh;
538 
539 	/* n->nud_state and hh->hh_len could be changed under us.
540 	 * neigh_hh_output() is taking care of the race later.
541 	 */
542 	if (!skip_cache &&
543 	    (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
544 	    READ_ONCE(hh->hh_len))
545 		return neigh_hh_output(hh, skb);
546 
547 	return READ_ONCE(n->output)(n, skb);
548 }
549 
550 static inline struct neighbour *
__neigh_lookup(struct neigh_table * tbl,const void * pkey,struct net_device * dev,int creat)551 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
552 {
553 	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
554 
555 	if (n || !creat)
556 		return n;
557 
558 	n = neigh_create(tbl, pkey, dev);
559 	return IS_ERR(n) ? NULL : n;
560 }
561 
562 static inline struct neighbour *
__neigh_lookup_errno(struct neigh_table * tbl,const void * pkey,struct net_device * dev)563 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
564   struct net_device *dev)
565 {
566 	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
567 
568 	if (n)
569 		return n;
570 
571 	return neigh_create(tbl, pkey, dev);
572 }
573 
574 struct neighbour_cb {
575 	unsigned long sched_next;
576 	unsigned int flags;
577 };
578 
579 #define LOCALLY_ENQUEUED 0x1
580 
581 #define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
582 
neigh_ha_snapshot(char * dst,const struct neighbour * n,const struct net_device * dev)583 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
584 				     const struct net_device *dev)
585 {
586 	unsigned int seq;
587 
588 	do {
589 		seq = read_seqbegin(&n->ha_lock);
590 		memcpy(dst, n->ha, dev->addr_len);
591 	} while (read_seqretry(&n->ha_lock, seq));
592 }
593 
neigh_update_is_router(struct neighbour * neigh,u32 flags,int * notify)594 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
595 					  int *notify)
596 {
597 	u8 ndm_flags = 0;
598 
599 	ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
600 	if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
601 		if (ndm_flags & NTF_ROUTER)
602 			neigh->flags |= NTF_ROUTER;
603 		else
604 			neigh->flags &= ~NTF_ROUTER;
605 		*notify = 1;
606 	}
607 }
608 #endif
609