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_GC_STALETIME,
52 	NEIGH_VAR_QUEUE_LEN_BYTES,
53 	NEIGH_VAR_PROXY_QLEN,
54 	NEIGH_VAR_ANYCAST_DELAY,
55 	NEIGH_VAR_PROXY_DELAY,
56 	NEIGH_VAR_LOCKTIME,
57 #define NEIGH_VAR_DATA_MAX (NEIGH_VAR_LOCKTIME + 1)
58 	/* Following are used as a second way to access one of the above */
59 	NEIGH_VAR_QUEUE_LEN, /* same data as NEIGH_VAR_QUEUE_LEN_BYTES */
60 	NEIGH_VAR_RETRANS_TIME_MS, /* same data as NEIGH_VAR_RETRANS_TIME */
61 	NEIGH_VAR_BASE_REACHABLE_TIME_MS, /* same data as NEIGH_VAR_BASE_REACHABLE_TIME */
62 	/* Following are used by "default" only */
63 	NEIGH_VAR_GC_INTERVAL,
64 	NEIGH_VAR_GC_THRESH1,
65 	NEIGH_VAR_GC_THRESH2,
66 	NEIGH_VAR_GC_THRESH3,
67 	NEIGH_VAR_MAX
68 };
69 
70 struct neigh_parms {
71 	possible_net_t net;
72 	struct net_device *dev;
73 	netdevice_tracker dev_tracker;
74 	struct list_head list;
75 	int	(*neigh_setup)(struct neighbour *);
76 	struct neigh_table *tbl;
77 
78 	void	*sysctl_table;
79 
80 	int dead;
81 	refcount_t refcnt;
82 	struct rcu_head rcu_head;
83 
84 	int	reachable_time;
85 	int	data[NEIGH_VAR_DATA_MAX];
86 	DECLARE_BITMAP(data_state, NEIGH_VAR_DATA_MAX);
87 };
88 
neigh_var_set(struct neigh_parms * p,int index,int val)89 static inline void neigh_var_set(struct neigh_parms *p, int index, int val)
90 {
91 	set_bit(index, p->data_state);
92 	p->data[index] = val;
93 }
94 
95 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
96 
97 /* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
98  * In other cases, NEIGH_VAR_SET should be used.
99  */
100 #define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
101 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
102 
neigh_parms_data_state_setall(struct neigh_parms * p)103 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)
104 {
105 	bitmap_fill(p->data_state, NEIGH_VAR_DATA_MAX);
106 }
107 
neigh_parms_data_state_cleanall(struct neigh_parms * p)108 static inline void neigh_parms_data_state_cleanall(struct neigh_parms *p)
109 {
110 	bitmap_zero(p->data_state, NEIGH_VAR_DATA_MAX);
111 }
112 
113 struct neigh_statistics {
114 	unsigned long allocs;		/* number of allocated neighs */
115 	unsigned long destroys;		/* number of destroyed neighs */
116 	unsigned long hash_grows;	/* number of hash resizes */
117 
118 	unsigned long res_failed;	/* number of failed resolutions */
119 
120 	unsigned long lookups;		/* number of lookups */
121 	unsigned long hits;		/* number of hits (among lookups) */
122 
123 	unsigned long rcv_probes_mcast;	/* number of received mcast ipv6 */
124 	unsigned long rcv_probes_ucast; /* number of received ucast ipv6 */
125 
126 	unsigned long periodic_gc_runs;	/* number of periodic GC runs */
127 	unsigned long forced_gc_runs;	/* number of forced GC runs */
128 
129 	unsigned long unres_discards;	/* number of unresolved drops */
130 	unsigned long table_fulls;      /* times even gc couldn't help */
131 };
132 
133 #define NEIGH_CACHE_STAT_INC(tbl, field) this_cpu_inc((tbl)->stats->field)
134 
135 struct neighbour {
136 	struct neighbour __rcu	*next;
137 	struct neigh_table	*tbl;
138 	struct neigh_parms	*parms;
139 	unsigned long		confirmed;
140 	unsigned long		updated;
141 	rwlock_t		lock;
142 	refcount_t		refcnt;
143 	unsigned int		arp_queue_len_bytes;
144 	struct sk_buff_head	arp_queue;
145 	struct timer_list	timer;
146 	unsigned long		used;
147 	atomic_t		probes;
148 	u8			nud_state;
149 	u8			type;
150 	u8			dead;
151 	u8			protocol;
152 	u32			flags;
153 	seqlock_t		ha_lock;
154 	unsigned char		ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);
155 	struct hh_cache		hh;
156 	int			(*output)(struct neighbour *, struct sk_buff *);
157 	const struct neigh_ops	*ops;
158 	struct list_head	gc_list;
159 	struct list_head	managed_list;
160 	struct rcu_head		rcu;
161 	struct net_device	*dev;
162 	netdevice_tracker	dev_tracker;
163 	u8			primary_key[0];
164 } __randomize_layout;
165 
166 struct neigh_ops {
167 	int			family;
168 	void			(*solicit)(struct neighbour *, struct sk_buff *);
169 	void			(*error_report)(struct neighbour *, struct sk_buff *);
170 	int			(*output)(struct neighbour *, struct sk_buff *);
171 	int			(*connected_output)(struct neighbour *, struct sk_buff *);
172 };
173 
174 struct pneigh_entry {
175 	struct pneigh_entry	*next;
176 	possible_net_t		net;
177 	struct net_device	*dev;
178 	netdevice_tracker	dev_tracker;
179 	u32			flags;
180 	u8			protocol;
181 	u8			key[];
182 };
183 
184 /*
185  *	neighbour table manipulation
186  */
187 
188 #define NEIGH_NUM_HASH_RND	4
189 
190 struct neigh_hash_table {
191 	struct neighbour __rcu	**hash_buckets;
192 	unsigned int		hash_shift;
193 	__u32			hash_rnd[NEIGH_NUM_HASH_RND];
194 	struct rcu_head		rcu;
195 };
196 
197 
198 struct neigh_table {
199 	int			family;
200 	unsigned int		entry_size;
201 	unsigned int		key_len;
202 	__be16			protocol;
203 	__u32			(*hash)(const void *pkey,
204 					const struct net_device *dev,
205 					__u32 *hash_rnd);
206 	bool			(*key_eq)(const struct neighbour *, const void *pkey);
207 	int			(*constructor)(struct neighbour *);
208 	int			(*pconstructor)(struct pneigh_entry *);
209 	void			(*pdestructor)(struct pneigh_entry *);
210 	void			(*proxy_redo)(struct sk_buff *skb);
211 	int			(*is_multicast)(const void *pkey);
212 	bool			(*allow_add)(const struct net_device *dev,
213 					     struct netlink_ext_ack *extack);
214 	char			*id;
215 	struct neigh_parms	parms;
216 	struct list_head	parms_list;
217 	int			gc_interval;
218 	int			gc_thresh1;
219 	int			gc_thresh2;
220 	int			gc_thresh3;
221 	unsigned long		last_flush;
222 	struct delayed_work	gc_work;
223 	struct delayed_work	managed_work;
224 	struct timer_list 	proxy_timer;
225 	struct sk_buff_head	proxy_queue;
226 	atomic_t		entries;
227 	atomic_t		gc_entries;
228 	struct list_head	gc_list;
229 	struct list_head	managed_list;
230 	rwlock_t		lock;
231 	unsigned long		last_rand;
232 	struct neigh_statistics	__percpu *stats;
233 	struct neigh_hash_table __rcu *nht;
234 	struct pneigh_entry	**phash_buckets;
235 };
236 
237 enum {
238 	NEIGH_ARP_TABLE = 0,
239 	NEIGH_ND_TABLE = 1,
240 	NEIGH_DN_TABLE = 2,
241 	NEIGH_NR_TABLES,
242 	NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
243 };
244 
neigh_parms_family(struct neigh_parms * p)245 static inline int neigh_parms_family(struct neigh_parms *p)
246 {
247 	return p->tbl->family;
248 }
249 
250 #define NEIGH_PRIV_ALIGN	sizeof(long long)
251 #define NEIGH_ENTRY_SIZE(size)	ALIGN((size), NEIGH_PRIV_ALIGN)
252 
neighbour_priv(const struct neighbour * n)253 static inline void *neighbour_priv(const struct neighbour *n)
254 {
255 	return (char *)n + n->tbl->entry_size;
256 }
257 
258 /* flags for neigh_update() */
259 #define NEIGH_UPDATE_F_OVERRIDE			BIT(0)
260 #define NEIGH_UPDATE_F_WEAK_OVERRIDE		BIT(1)
261 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER	BIT(2)
262 #define NEIGH_UPDATE_F_USE			BIT(3)
263 #define NEIGH_UPDATE_F_MANAGED			BIT(4)
264 #define NEIGH_UPDATE_F_EXT_LEARNED		BIT(5)
265 #define NEIGH_UPDATE_F_ISROUTER			BIT(6)
266 #define NEIGH_UPDATE_F_ADMIN			BIT(7)
267 
268 /* In-kernel representation for NDA_FLAGS_EXT flags: */
269 #define NTF_OLD_MASK		0xff
270 #define NTF_EXT_SHIFT		8
271 #define NTF_EXT_MASK		(NTF_EXT_MANAGED)
272 
273 #define NTF_MANAGED		(NTF_EXT_MANAGED << NTF_EXT_SHIFT)
274 
275 extern const struct nla_policy nda_policy[];
276 
neigh_key_eq16(const struct neighbour * n,const void * pkey)277 static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
278 {
279 	return *(const u16 *)n->primary_key == *(const u16 *)pkey;
280 }
281 
neigh_key_eq32(const struct neighbour * n,const void * pkey)282 static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
283 {
284 	return *(const u32 *)n->primary_key == *(const u32 *)pkey;
285 }
286 
neigh_key_eq128(const struct neighbour * n,const void * pkey)287 static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
288 {
289 	const u32 *n32 = (const u32 *)n->primary_key;
290 	const u32 *p32 = pkey;
291 
292 	return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
293 		(n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
294 }
295 
___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)296 static inline struct neighbour *___neigh_lookup_noref(
297 	struct neigh_table *tbl,
298 	bool (*key_eq)(const struct neighbour *n, const void *pkey),
299 	__u32 (*hash)(const void *pkey,
300 		      const struct net_device *dev,
301 		      __u32 *hash_rnd),
302 	const void *pkey,
303 	struct net_device *dev)
304 {
305 	struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
306 	struct neighbour *n;
307 	u32 hash_val;
308 
309 	hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
310 	for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
311 	     n != NULL;
312 	     n = rcu_dereference_bh(n->next)) {
313 		if (n->dev == dev && key_eq(n, pkey))
314 			return n;
315 	}
316 
317 	return NULL;
318 }
319 
__neigh_lookup_noref(struct neigh_table * tbl,const void * pkey,struct net_device * dev)320 static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
321 						     const void *pkey,
322 						     struct net_device *dev)
323 {
324 	return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
325 }
326 
neigh_confirm(struct neighbour * n)327 static inline void neigh_confirm(struct neighbour *n)
328 {
329 	if (n) {
330 		unsigned long now = jiffies;
331 
332 		/* avoid dirtying neighbour */
333 		if (READ_ONCE(n->confirmed) != now)
334 			WRITE_ONCE(n->confirmed, now);
335 	}
336 }
337 
338 void neigh_table_init(int index, struct neigh_table *tbl);
339 int neigh_table_clear(int index, struct neigh_table *tbl);
340 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
341 			       struct net_device *dev);
342 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
343 				     const void *pkey);
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, struct neigh_table *tbl);
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 creat);
386 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
387 				     const void *key, struct net_device *dev);
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 void pneigh_for_each(struct neigh_table *tbl,
403 		     void (*cb)(struct pneigh_entry *));
404 
405 struct neigh_seq_state {
406 	struct seq_net_private p;
407 	struct neigh_table *tbl;
408 	struct neigh_hash_table *nht;
409 	void *(*neigh_sub_iter)(struct neigh_seq_state *state,
410 				struct neighbour *n, loff_t *pos);
411 	unsigned int bucket;
412 	unsigned int flags;
413 #define NEIGH_SEQ_NEIGH_ONLY	0x00000001
414 #define NEIGH_SEQ_IS_PNEIGH	0x00000002
415 #define NEIGH_SEQ_SKIP_NOARP	0x00000004
416 };
417 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
418 		      unsigned int);
419 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
420 void neigh_seq_stop(struct seq_file *, void *);
421 
422 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
423 			void *buffer, size_t *lenp, loff_t *ppos);
424 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
425 				void *buffer,
426 				size_t *lenp, loff_t *ppos);
427 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
428 				   void *buffer, size_t *lenp, loff_t *ppos);
429 
430 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
431 			  proc_handler *proc_handler);
432 void neigh_sysctl_unregister(struct neigh_parms *p);
433 
__neigh_parms_put(struct neigh_parms * parms)434 static inline void __neigh_parms_put(struct neigh_parms *parms)
435 {
436 	refcount_dec(&parms->refcnt);
437 }
438 
neigh_parms_clone(struct neigh_parms * parms)439 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
440 {
441 	refcount_inc(&parms->refcnt);
442 	return parms;
443 }
444 
445 /*
446  *	Neighbour references
447  */
448 
neigh_release(struct neighbour * neigh)449 static inline void neigh_release(struct neighbour *neigh)
450 {
451 	if (refcount_dec_and_test(&neigh->refcnt))
452 		neigh_destroy(neigh);
453 }
454 
neigh_clone(struct neighbour * neigh)455 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
456 {
457 	if (neigh)
458 		refcount_inc(&neigh->refcnt);
459 	return neigh;
460 }
461 
462 #define neigh_hold(n)	refcount_inc(&(n)->refcnt)
463 
neigh_event_send_probe(struct neighbour * neigh,struct sk_buff * skb,const bool immediate_ok)464 static __always_inline int neigh_event_send_probe(struct neighbour *neigh,
465 						  struct sk_buff *skb,
466 						  const bool immediate_ok)
467 {
468 	unsigned long now = jiffies;
469 
470 	if (READ_ONCE(neigh->used) != now)
471 		WRITE_ONCE(neigh->used, now);
472 	if (!(neigh->nud_state & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE)))
473 		return __neigh_event_send(neigh, skb, immediate_ok);
474 	return 0;
475 }
476 
neigh_event_send(struct neighbour * neigh,struct sk_buff * skb)477 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
478 {
479 	return neigh_event_send_probe(neigh, skb, true);
480 }
481 
482 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
neigh_hh_bridge(struct hh_cache * hh,struct sk_buff * skb)483 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
484 {
485 	unsigned int seq, hh_alen;
486 
487 	do {
488 		seq = read_seqbegin(&hh->hh_lock);
489 		hh_alen = HH_DATA_ALIGN(ETH_HLEN);
490 		memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
491 	} while (read_seqretry(&hh->hh_lock, seq));
492 	return 0;
493 }
494 #endif
495 
neigh_hh_output(const struct hh_cache * hh,struct sk_buff * skb)496 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
497 {
498 	unsigned int hh_alen = 0;
499 	unsigned int seq;
500 	unsigned int hh_len;
501 
502 	do {
503 		seq = read_seqbegin(&hh->hh_lock);
504 		hh_len = READ_ONCE(hh->hh_len);
505 		if (likely(hh_len <= HH_DATA_MOD)) {
506 			hh_alen = HH_DATA_MOD;
507 
508 			/* skb_push() would proceed silently if we have room for
509 			 * the unaligned size but not for the aligned size:
510 			 * check headroom explicitly.
511 			 */
512 			if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
513 				/* this is inlined by gcc */
514 				memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
515 				       HH_DATA_MOD);
516 			}
517 		} else {
518 			hh_alen = HH_DATA_ALIGN(hh_len);
519 
520 			if (likely(skb_headroom(skb) >= hh_alen)) {
521 				memcpy(skb->data - hh_alen, hh->hh_data,
522 				       hh_alen);
523 			}
524 		}
525 	} while (read_seqretry(&hh->hh_lock, seq));
526 
527 	if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
528 		kfree_skb(skb);
529 		return NET_XMIT_DROP;
530 	}
531 
532 	__skb_push(skb, hh_len);
533 	return dev_queue_xmit(skb);
534 }
535 
neigh_output(struct neighbour * n,struct sk_buff * skb,bool skip_cache)536 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
537 			       bool skip_cache)
538 {
539 	const struct hh_cache *hh = &n->hh;
540 
541 	/* n->nud_state and hh->hh_len could be changed under us.
542 	 * neigh_hh_output() is taking care of the race later.
543 	 */
544 	if (!skip_cache &&
545 	    (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
546 	    READ_ONCE(hh->hh_len))
547 		return neigh_hh_output(hh, skb);
548 
549 	return n->output(n, skb);
550 }
551 
552 static inline struct neighbour *
__neigh_lookup(struct neigh_table * tbl,const void * pkey,struct net_device * dev,int creat)553 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
554 {
555 	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
556 
557 	if (n || !creat)
558 		return n;
559 
560 	n = neigh_create(tbl, pkey, dev);
561 	return IS_ERR(n) ? NULL : n;
562 }
563 
564 static inline struct neighbour *
__neigh_lookup_errno(struct neigh_table * tbl,const void * pkey,struct net_device * dev)565 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
566   struct net_device *dev)
567 {
568 	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
569 
570 	if (n)
571 		return n;
572 
573 	return neigh_create(tbl, pkey, dev);
574 }
575 
576 struct neighbour_cb {
577 	unsigned long sched_next;
578 	unsigned int flags;
579 };
580 
581 #define LOCALLY_ENQUEUED 0x1
582 
583 #define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
584 
neigh_ha_snapshot(char * dst,const struct neighbour * n,const struct net_device * dev)585 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
586 				     const struct net_device *dev)
587 {
588 	unsigned int seq;
589 
590 	do {
591 		seq = read_seqbegin(&n->ha_lock);
592 		memcpy(dst, n->ha, dev->addr_len);
593 	} while (read_seqretry(&n->ha_lock, seq));
594 }
595 
neigh_update_is_router(struct neighbour * neigh,u32 flags,int * notify)596 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
597 					  int *notify)
598 {
599 	u8 ndm_flags = 0;
600 
601 	ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
602 	if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
603 		if (ndm_flags & NTF_ROUTER)
604 			neigh->flags |= NTF_ROUTER;
605 		else
606 			neigh->flags &= ~NTF_ROUTER;
607 		*notify = 1;
608 	}
609 }
610 #endif
611