xref: /openbmc/linux/include/net/neighbour.h (revision f4356947)
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 
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 
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 
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 
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 
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 
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 
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 
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(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(nht->hash_buckets[hash_val]);
308 	     n != NULL;
309 	     n = rcu_dereference(n->next)) {
310 		if (n->dev == dev && key_eq(n, pkey))
311 			return n;
312 	}
313 
314 	return NULL;
315 }
316 
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 
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_create(struct neigh_table *tbl, const void *pkey,
340 				 struct net_device *dev, bool want_ref);
341 static inline struct neighbour *neigh_create(struct neigh_table *tbl,
342 					     const void *pkey,
343 					     struct net_device *dev)
344 {
345 	return __neigh_create(tbl, pkey, dev, true);
346 }
347 void neigh_destroy(struct neighbour *neigh);
348 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
349 		       const bool immediate_ok);
350 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, u32 flags,
351 		 u32 nlmsg_pid);
352 void __neigh_set_probe_once(struct neighbour *neigh);
353 bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl);
354 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev);
355 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
356 int neigh_carrier_down(struct neigh_table *tbl, struct net_device *dev);
357 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb);
358 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb);
359 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb);
360 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
361 						u8 *lladdr, void *saddr,
362 						struct net_device *dev);
363 
364 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
365 				      struct neigh_table *tbl);
366 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
367 
368 static inline
369 struct net *neigh_parms_net(const struct neigh_parms *parms)
370 {
371 	return read_pnet(&parms->net);
372 }
373 
374 unsigned long neigh_rand_reach_time(unsigned long base);
375 
376 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
377 		    struct sk_buff *skb);
378 struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net,
379 				   const void *key, struct net_device *dev,
380 				   int creat);
381 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl, struct net *net,
382 				     const void *key, struct net_device *dev);
383 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key,
384 		  struct net_device *dev);
385 
386 static inline struct net *pneigh_net(const struct pneigh_entry *pneigh)
387 {
388 	return read_pnet(&pneigh->net);
389 }
390 
391 void neigh_app_ns(struct neighbour *n);
392 void neigh_for_each(struct neigh_table *tbl,
393 		    void (*cb)(struct neighbour *, void *), void *cookie);
394 void __neigh_for_each_release(struct neigh_table *tbl,
395 			      int (*cb)(struct neighbour *));
396 int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
397 void pneigh_for_each(struct neigh_table *tbl,
398 		     void (*cb)(struct pneigh_entry *));
399 
400 struct neigh_seq_state {
401 	struct seq_net_private p;
402 	struct neigh_table *tbl;
403 	struct neigh_hash_table *nht;
404 	void *(*neigh_sub_iter)(struct neigh_seq_state *state,
405 				struct neighbour *n, loff_t *pos);
406 	unsigned int bucket;
407 	unsigned int flags;
408 #define NEIGH_SEQ_NEIGH_ONLY	0x00000001
409 #define NEIGH_SEQ_IS_PNEIGH	0x00000002
410 #define NEIGH_SEQ_SKIP_NOARP	0x00000004
411 };
412 void *neigh_seq_start(struct seq_file *, loff_t *, struct neigh_table *,
413 		      unsigned int);
414 void *neigh_seq_next(struct seq_file *, void *, loff_t *);
415 void neigh_seq_stop(struct seq_file *, void *);
416 
417 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
418 			void *buffer, size_t *lenp, loff_t *ppos);
419 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
420 				void *buffer,
421 				size_t *lenp, loff_t *ppos);
422 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
423 				   void *buffer, size_t *lenp, loff_t *ppos);
424 
425 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
426 			  proc_handler *proc_handler);
427 void neigh_sysctl_unregister(struct neigh_parms *p);
428 
429 static inline void __neigh_parms_put(struct neigh_parms *parms)
430 {
431 	refcount_dec(&parms->refcnt);
432 }
433 
434 static inline struct neigh_parms *neigh_parms_clone(struct neigh_parms *parms)
435 {
436 	refcount_inc(&parms->refcnt);
437 	return parms;
438 }
439 
440 /*
441  *	Neighbour references
442  */
443 
444 static inline void neigh_release(struct neighbour *neigh)
445 {
446 	if (refcount_dec_and_test(&neigh->refcnt))
447 		neigh_destroy(neigh);
448 }
449 
450 static inline struct neighbour * neigh_clone(struct neighbour *neigh)
451 {
452 	if (neigh)
453 		refcount_inc(&neigh->refcnt);
454 	return neigh;
455 }
456 
457 #define neigh_hold(n)	refcount_inc(&(n)->refcnt)
458 
459 static __always_inline int neigh_event_send_probe(struct neighbour *neigh,
460 						  struct sk_buff *skb,
461 						  const bool immediate_ok)
462 {
463 	unsigned long now = jiffies;
464 
465 	if (READ_ONCE(neigh->used) != now)
466 		WRITE_ONCE(neigh->used, now);
467 	if (!(READ_ONCE(neigh->nud_state) & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE)))
468 		return __neigh_event_send(neigh, skb, immediate_ok);
469 	return 0;
470 }
471 
472 static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
473 {
474 	return neigh_event_send_probe(neigh, skb, true);
475 }
476 
477 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
478 static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb)
479 {
480 	unsigned int seq, hh_alen;
481 
482 	do {
483 		seq = read_seqbegin(&hh->hh_lock);
484 		hh_alen = HH_DATA_ALIGN(ETH_HLEN);
485 		memcpy(skb->data - hh_alen, hh->hh_data, ETH_ALEN + hh_alen - ETH_HLEN);
486 	} while (read_seqretry(&hh->hh_lock, seq));
487 	return 0;
488 }
489 #endif
490 
491 static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
492 {
493 	unsigned int hh_alen = 0;
494 	unsigned int seq;
495 	unsigned int hh_len;
496 
497 	do {
498 		seq = read_seqbegin(&hh->hh_lock);
499 		hh_len = READ_ONCE(hh->hh_len);
500 		if (likely(hh_len <= HH_DATA_MOD)) {
501 			hh_alen = HH_DATA_MOD;
502 
503 			/* skb_push() would proceed silently if we have room for
504 			 * the unaligned size but not for the aligned size:
505 			 * check headroom explicitly.
506 			 */
507 			if (likely(skb_headroom(skb) >= HH_DATA_MOD)) {
508 				/* this is inlined by gcc */
509 				memcpy(skb->data - HH_DATA_MOD, hh->hh_data,
510 				       HH_DATA_MOD);
511 			}
512 		} else {
513 			hh_alen = HH_DATA_ALIGN(hh_len);
514 
515 			if (likely(skb_headroom(skb) >= hh_alen)) {
516 				memcpy(skb->data - hh_alen, hh->hh_data,
517 				       hh_alen);
518 			}
519 		}
520 	} while (read_seqretry(&hh->hh_lock, seq));
521 
522 	if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) {
523 		kfree_skb(skb);
524 		return NET_XMIT_DROP;
525 	}
526 
527 	__skb_push(skb, hh_len);
528 	return dev_queue_xmit(skb);
529 }
530 
531 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
532 			       bool skip_cache)
533 {
534 	const struct hh_cache *hh = &n->hh;
535 
536 	/* n->nud_state and hh->hh_len could be changed under us.
537 	 * neigh_hh_output() is taking care of the race later.
538 	 */
539 	if (!skip_cache &&
540 	    (READ_ONCE(n->nud_state) & NUD_CONNECTED) &&
541 	    READ_ONCE(hh->hh_len))
542 		return neigh_hh_output(hh, skb);
543 
544 	return n->output(n, skb);
545 }
546 
547 static inline struct neighbour *
548 __neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
549 {
550 	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
551 
552 	if (n || !creat)
553 		return n;
554 
555 	n = neigh_create(tbl, pkey, dev);
556 	return IS_ERR(n) ? NULL : n;
557 }
558 
559 static inline struct neighbour *
560 __neigh_lookup_errno(struct neigh_table *tbl, const void *pkey,
561   struct net_device *dev)
562 {
563 	struct neighbour *n = neigh_lookup(tbl, pkey, dev);
564 
565 	if (n)
566 		return n;
567 
568 	return neigh_create(tbl, pkey, dev);
569 }
570 
571 struct neighbour_cb {
572 	unsigned long sched_next;
573 	unsigned int flags;
574 };
575 
576 #define LOCALLY_ENQUEUED 0x1
577 
578 #define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
579 
580 static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
581 				     const struct net_device *dev)
582 {
583 	unsigned int seq;
584 
585 	do {
586 		seq = read_seqbegin(&n->ha_lock);
587 		memcpy(dst, n->ha, dev->addr_len);
588 	} while (read_seqretry(&n->ha_lock, seq));
589 }
590 
591 static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,
592 					  int *notify)
593 {
594 	u8 ndm_flags = 0;
595 
596 	ndm_flags |= (flags & NEIGH_UPDATE_F_ISROUTER) ? NTF_ROUTER : 0;
597 	if ((neigh->flags ^ ndm_flags) & NTF_ROUTER) {
598 		if (ndm_flags & NTF_ROUTER)
599 			neigh->flags |= NTF_ROUTER;
600 		else
601 			neigh->flags &= ~NTF_ROUTER;
602 		*notify = 1;
603 	}
604 }
605 #endif
606