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TOMOYO Linux Cross Reference
Linux/net/core/neighbour.c

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  1 /*
  2  *      Generic address resolution entity
  3  *
  4  *      Authors:
  5  *      Pedro Roque             <roque@di.fc.ul.pt>
  6  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
  7  *
  8  *      This program is free software; you can redistribute it and/or
  9  *      modify it under the terms of the GNU General Public License
 10  *      as published by the Free Software Foundation; either version
 11  *      2 of the License, or (at your option) any later version.
 12  *
 13  *      Fixes:
 14  *      Vitaly E. Lavrov        releasing NULL neighbor in neigh_add.
 15  *      Harald Welte            Add neighbour cache statistics like rtstat
 16  */
 17 
 18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 19 
 20 #include <linux/slab.h>
 21 #include <linux/types.h>
 22 #include <linux/kernel.h>
 23 #include <linux/module.h>
 24 #include <linux/socket.h>
 25 #include <linux/netdevice.h>
 26 #include <linux/proc_fs.h>
 27 #ifdef CONFIG_SYSCTL
 28 #include <linux/sysctl.h>
 29 #endif
 30 #include <linux/times.h>
 31 #include <net/net_namespace.h>
 32 #include <net/neighbour.h>
 33 #include <net/dst.h>
 34 #include <net/sock.h>
 35 #include <net/netevent.h>
 36 #include <net/netlink.h>
 37 #include <linux/rtnetlink.h>
 38 #include <linux/random.h>
 39 #include <linux/string.h>
 40 #include <linux/log2.h>
 41 #include <linux/inetdevice.h>
 42 #include <net/addrconf.h>
 43 
 44 #define DEBUG
 45 #define NEIGH_DEBUG 1
 46 #define neigh_dbg(level, fmt, ...)              \
 47 do {                                            \
 48         if (level <= NEIGH_DEBUG)               \
 49                 pr_debug(fmt, ##__VA_ARGS__);   \
 50 } while (0)
 51 
 52 #define PNEIGH_HASHMASK         0xF
 53 
 54 static void neigh_timer_handler(unsigned long arg);
 55 static void __neigh_notify(struct neighbour *n, int type, int flags);
 56 static void neigh_update_notify(struct neighbour *neigh);
 57 static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
 58 
 59 #ifdef CONFIG_PROC_FS
 60 static const struct file_operations neigh_stat_seq_fops;
 61 #endif
 62 
 63 /*
 64    Neighbour hash table buckets are protected with rwlock tbl->lock.
 65 
 66    - All the scans/updates to hash buckets MUST be made under this lock.
 67    - NOTHING clever should be made under this lock: no callbacks
 68      to protocol backends, no attempts to send something to network.
 69      It will result in deadlocks, if backend/driver wants to use neighbour
 70      cache.
 71    - If the entry requires some non-trivial actions, increase
 72      its reference count and release table lock.
 73 
 74    Neighbour entries are protected:
 75    - with reference count.
 76    - with rwlock neigh->lock
 77 
 78    Reference count prevents destruction.
 79 
 80    neigh->lock mainly serializes ll address data and its validity state.
 81    However, the same lock is used to protect another entry fields:
 82     - timer
 83     - resolution queue
 84 
 85    Again, nothing clever shall be made under neigh->lock,
 86    the most complicated procedure, which we allow is dev->hard_header.
 87    It is supposed, that dev->hard_header is simplistic and does
 88    not make callbacks to neighbour tables.
 89  */
 90 
 91 static int neigh_blackhole(struct neighbour *neigh, struct sk_buff *skb)
 92 {
 93         kfree_skb(skb);
 94         return -ENETDOWN;
 95 }
 96 
 97 static void neigh_cleanup_and_release(struct neighbour *neigh)
 98 {
 99         if (neigh->parms->neigh_cleanup)
100                 neigh->parms->neigh_cleanup(neigh);
101 
102         __neigh_notify(neigh, RTM_DELNEIGH, 0);
103         neigh_release(neigh);
104 }
105 
106 /*
107  * It is random distribution in the interval (1/2)*base...(3/2)*base.
108  * It corresponds to default IPv6 settings and is not overridable,
109  * because it is really reasonable choice.
110  */
111 
112 unsigned long neigh_rand_reach_time(unsigned long base)
113 {
114         return base ? (prandom_u32() % base) + (base >> 1) : 0;
115 }
116 EXPORT_SYMBOL(neigh_rand_reach_time);
117 
118 
119 static int neigh_forced_gc(struct neigh_table *tbl)
120 {
121         int shrunk = 0;
122         int i;
123         struct neigh_hash_table *nht;
124 
125         NEIGH_CACHE_STAT_INC(tbl, forced_gc_runs);
126 
127         write_lock_bh(&tbl->lock);
128         nht = rcu_dereference_protected(tbl->nht,
129                                         lockdep_is_held(&tbl->lock));
130         for (i = 0; i < (1 << nht->hash_shift); i++) {
131                 struct neighbour *n;
132                 struct neighbour __rcu **np;
133 
134                 np = &nht->hash_buckets[i];
135                 while ((n = rcu_dereference_protected(*np,
136                                         lockdep_is_held(&tbl->lock))) != NULL) {
137                         /* Neighbour record may be discarded if:
138                          * - nobody refers to it.
139                          * - it is not permanent
140                          */
141                         write_lock(&n->lock);
142                         if (atomic_read(&n->refcnt) == 1 &&
143                             !(n->nud_state & NUD_PERMANENT)) {
144                                 rcu_assign_pointer(*np,
145                                         rcu_dereference_protected(n->next,
146                                                   lockdep_is_held(&tbl->lock)));
147                                 n->dead = 1;
148                                 shrunk  = 1;
149                                 write_unlock(&n->lock);
150                                 neigh_cleanup_and_release(n);
151                                 continue;
152                         }
153                         write_unlock(&n->lock);
154                         np = &n->next;
155                 }
156         }
157 
158         tbl->last_flush = jiffies;
159 
160         write_unlock_bh(&tbl->lock);
161 
162         return shrunk;
163 }
164 
165 static void neigh_add_timer(struct neighbour *n, unsigned long when)
166 {
167         neigh_hold(n);
168         if (unlikely(mod_timer(&n->timer, when))) {
169                 printk("NEIGH: BUG, double timer add, state is %x\n",
170                        n->nud_state);
171                 dump_stack();
172         }
173 }
174 
175 static int neigh_del_timer(struct neighbour *n)
176 {
177         if ((n->nud_state & NUD_IN_TIMER) &&
178             del_timer(&n->timer)) {
179                 neigh_release(n);
180                 return 1;
181         }
182         return 0;
183 }
184 
185 static void pneigh_queue_purge(struct sk_buff_head *list)
186 {
187         struct sk_buff *skb;
188 
189         while ((skb = skb_dequeue(list)) != NULL) {
190                 dev_put(skb->dev);
191                 kfree_skb(skb);
192         }
193 }
194 
195 static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev)
196 {
197         int i;
198         struct neigh_hash_table *nht;
199 
200         nht = rcu_dereference_protected(tbl->nht,
201                                         lockdep_is_held(&tbl->lock));
202 
203         for (i = 0; i < (1 << nht->hash_shift); i++) {
204                 struct neighbour *n;
205                 struct neighbour __rcu **np = &nht->hash_buckets[i];
206 
207                 while ((n = rcu_dereference_protected(*np,
208                                         lockdep_is_held(&tbl->lock))) != NULL) {
209                         if (dev && n->dev != dev) {
210                                 np = &n->next;
211                                 continue;
212                         }
213                         rcu_assign_pointer(*np,
214                                    rcu_dereference_protected(n->next,
215                                                 lockdep_is_held(&tbl->lock)));
216                         write_lock(&n->lock);
217                         neigh_del_timer(n);
218                         n->dead = 1;
219 
220                         if (atomic_read(&n->refcnt) != 1) {
221                                 /* The most unpleasant situation.
222                                    We must destroy neighbour entry,
223                                    but someone still uses it.
224 
225                                    The destroy will be delayed until
226                                    the last user releases us, but
227                                    we must kill timers etc. and move
228                                    it to safe state.
229                                  */
230                                 __skb_queue_purge(&n->arp_queue);
231                                 n->arp_queue_len_bytes = 0;
232                                 n->output = neigh_blackhole;
233                                 if (n->nud_state & NUD_VALID)
234                                         n->nud_state = NUD_NOARP;
235                                 else
236                                         n->nud_state = NUD_NONE;
237                                 neigh_dbg(2, "neigh %p is stray\n", n);
238                         }
239                         write_unlock(&n->lock);
240                         neigh_cleanup_and_release(n);
241                 }
242         }
243 }
244 
245 void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev)
246 {
247         write_lock_bh(&tbl->lock);
248         neigh_flush_dev(tbl, dev);
249         write_unlock_bh(&tbl->lock);
250 }
251 EXPORT_SYMBOL(neigh_changeaddr);
252 
253 int neigh_ifdown(struct neigh_table *tbl, struct net_device *dev)
254 {
255         write_lock_bh(&tbl->lock);
256         neigh_flush_dev(tbl, dev);
257         pneigh_ifdown(tbl, dev);
258         write_unlock_bh(&tbl->lock);
259 
260         del_timer_sync(&tbl->proxy_timer);
261         pneigh_queue_purge(&tbl->proxy_queue);
262         return 0;
263 }
264 EXPORT_SYMBOL(neigh_ifdown);
265 
266 static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device *dev)
267 {
268         struct neighbour *n = NULL;
269         unsigned long now = jiffies;
270         int entries;
271 
272         entries = atomic_inc_return(&tbl->entries) - 1;
273         if (entries >= tbl->gc_thresh3 ||
274             (entries >= tbl->gc_thresh2 &&
275              time_after(now, tbl->last_flush + 5 * HZ))) {
276                 if (!neigh_forced_gc(tbl) &&
277                     entries >= tbl->gc_thresh3) {
278                         net_info_ratelimited("%s: neighbor table overflow!\n",
279                                              tbl->id);
280                         NEIGH_CACHE_STAT_INC(tbl, table_fulls);
281                         goto out_entries;
282                 }
283         }
284 
285         n = kzalloc(tbl->entry_size + dev->neigh_priv_len, GFP_ATOMIC);
286         if (!n)
287                 goto out_entries;
288 
289         __skb_queue_head_init(&n->arp_queue);
290         rwlock_init(&n->lock);
291         seqlock_init(&n->ha_lock);
292         n->updated        = n->used = now;
293         n->nud_state      = NUD_NONE;
294         n->output         = neigh_blackhole;
295         seqlock_init(&n->hh.hh_lock);
296         n->parms          = neigh_parms_clone(&tbl->parms);
297         setup_timer(&n->timer, neigh_timer_handler, (unsigned long)n);
298 
299         NEIGH_CACHE_STAT_INC(tbl, allocs);
300         n->tbl            = tbl;
301         atomic_set(&n->refcnt, 1);
302         n->dead           = 1;
303 out:
304         return n;
305 
306 out_entries:
307         atomic_dec(&tbl->entries);
308         goto out;
309 }
310 
311 static void neigh_get_hash_rnd(u32 *x)
312 {
313         get_random_bytes(x, sizeof(*x));
314         *x |= 1;
315 }
316 
317 static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)
318 {
319         size_t size = (1 << shift) * sizeof(struct neighbour *);
320         struct neigh_hash_table *ret;
321         struct neighbour __rcu **buckets;
322         int i;
323 
324         ret = kmalloc(sizeof(*ret), GFP_ATOMIC);
325         if (!ret)
326                 return NULL;
327         if (size <= PAGE_SIZE)
328                 buckets = kzalloc(size, GFP_ATOMIC);
329         else
330                 buckets = (struct neighbour __rcu **)
331                           __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
332                                            get_order(size));
333         if (!buckets) {
334                 kfree(ret);
335                 return NULL;
336         }
337         ret->hash_buckets = buckets;
338         ret->hash_shift = shift;
339         for (i = 0; i < NEIGH_NUM_HASH_RND; i++)
340                 neigh_get_hash_rnd(&ret->hash_rnd[i]);
341         return ret;
342 }
343 
344 static void neigh_hash_free_rcu(struct rcu_head *head)
345 {
346         struct neigh_hash_table *nht = container_of(head,
347                                                     struct neigh_hash_table,
348                                                     rcu);
349         size_t size = (1 << nht->hash_shift) * sizeof(struct neighbour *);
350         struct neighbour __rcu **buckets = nht->hash_buckets;
351 
352         if (size <= PAGE_SIZE)
353                 kfree(buckets);
354         else
355                 free_pages((unsigned long)buckets, get_order(size));
356         kfree(nht);
357 }
358 
359 static struct neigh_hash_table *neigh_hash_grow(struct neigh_table *tbl,
360                                                 unsigned long new_shift)
361 {
362         unsigned int i, hash;
363         struct neigh_hash_table *new_nht, *old_nht;
364 
365         NEIGH_CACHE_STAT_INC(tbl, hash_grows);
366 
367         old_nht = rcu_dereference_protected(tbl->nht,
368                                             lockdep_is_held(&tbl->lock));
369         new_nht = neigh_hash_alloc(new_shift);
370         if (!new_nht)
371                 return old_nht;
372 
373         for (i = 0; i < (1 << old_nht->hash_shift); i++) {
374                 struct neighbour *n, *next;
375 
376                 for (n = rcu_dereference_protected(old_nht->hash_buckets[i],
377                                                    lockdep_is_held(&tbl->lock));
378                      n != NULL;
379                      n = next) {
380                         hash = tbl->hash(n->primary_key, n->dev,
381                                          new_nht->hash_rnd);
382 
383                         hash >>= (32 - new_nht->hash_shift);
384                         next = rcu_dereference_protected(n->next,
385                                                 lockdep_is_held(&tbl->lock));
386 
387                         rcu_assign_pointer(n->next,
388                                            rcu_dereference_protected(
389                                                 new_nht->hash_buckets[hash],
390                                                 lockdep_is_held(&tbl->lock)));
391                         rcu_assign_pointer(new_nht->hash_buckets[hash], n);
392                 }
393         }
394 
395         rcu_assign_pointer(tbl->nht, new_nht);
396         call_rcu(&old_nht->rcu, neigh_hash_free_rcu);
397         return new_nht;
398 }
399 
400 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
401                                struct net_device *dev)
402 {
403         struct neighbour *n;
404 
405         NEIGH_CACHE_STAT_INC(tbl, lookups);
406 
407         rcu_read_lock_bh();
408         n = __neigh_lookup_noref(tbl, pkey, dev);
409         if (n) {
410                 if (!atomic_inc_not_zero(&n->refcnt))
411                         n = NULL;
412                 NEIGH_CACHE_STAT_INC(tbl, hits);
413         }
414 
415         rcu_read_unlock_bh();
416         return n;
417 }
418 EXPORT_SYMBOL(neigh_lookup);
419 
420 struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
421                                      const void *pkey)
422 {
423         struct neighbour *n;
424         int key_len = tbl->key_len;
425         u32 hash_val;
426         struct neigh_hash_table *nht;
427 
428         NEIGH_CACHE_STAT_INC(tbl, lookups);
429 
430         rcu_read_lock_bh();
431         nht = rcu_dereference_bh(tbl->nht);
432         hash_val = tbl->hash(pkey, NULL, nht->hash_rnd) >> (32 - nht->hash_shift);
433 
434         for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
435              n != NULL;
436              n = rcu_dereference_bh(n->next)) {
437                 if (!memcmp(n->primary_key, pkey, key_len) &&
438                     net_eq(dev_net(n->dev), net)) {
439                         if (!atomic_inc_not_zero(&n->refcnt))
440                                 n = NULL;
441                         NEIGH_CACHE_STAT_INC(tbl, hits);
442                         break;
443                 }
444         }
445 
446         rcu_read_unlock_bh();
447         return n;
448 }
449 EXPORT_SYMBOL(neigh_lookup_nodev);
450 
451 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
452                                  struct net_device *dev, bool want_ref)
453 {
454         u32 hash_val;
455         int key_len = tbl->key_len;
456         int error;
457         struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev);
458         struct neigh_hash_table *nht;
459 
460         if (!n) {
461                 rc = ERR_PTR(-ENOBUFS);
462                 goto out;
463         }
464 
465         memcpy(n->primary_key, pkey, key_len);
466         n->dev = dev;
467         dev_hold(dev);
468 
469         /* Protocol specific setup. */
470         if (tbl->constructor && (error = tbl->constructor(n)) < 0) {
471                 rc = ERR_PTR(error);
472                 goto out_neigh_release;
473         }
474 
475         if (dev->netdev_ops->ndo_neigh_construct) {
476                 error = dev->netdev_ops->ndo_neigh_construct(n);
477                 if (error < 0) {
478                         rc = ERR_PTR(error);
479                         goto out_neigh_release;
480                 }
481         }
482 
483         /* Device specific setup. */
484         if (n->parms->neigh_setup &&
485             (error = n->parms->neigh_setup(n)) < 0) {
486                 rc = ERR_PTR(error);
487                 goto out_neigh_release;
488         }
489 
490         n->confirmed = jiffies - (NEIGH_VAR(n->parms, BASE_REACHABLE_TIME) << 1);
491 
492         write_lock_bh(&tbl->lock);
493         nht = rcu_dereference_protected(tbl->nht,
494                                         lockdep_is_held(&tbl->lock));
495 
496         if (atomic_read(&tbl->entries) > (1 << nht->hash_shift))
497                 nht = neigh_hash_grow(tbl, nht->hash_shift + 1);
498 
499         hash_val = tbl->hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
500 
501         if (n->parms->dead) {
502                 rc = ERR_PTR(-EINVAL);
503                 goto out_tbl_unlock;
504         }
505 
506         for (n1 = rcu_dereference_protected(nht->hash_buckets[hash_val],
507                                             lockdep_is_held(&tbl->lock));
508              n1 != NULL;
509              n1 = rcu_dereference_protected(n1->next,
510                         lockdep_is_held(&tbl->lock))) {
511                 if (dev == n1->dev && !memcmp(n1->primary_key, pkey, key_len)) {
512                         if (want_ref)
513                                 neigh_hold(n1);
514                         rc = n1;
515                         goto out_tbl_unlock;
516                 }
517         }
518 
519         n->dead = 0;
520         if (want_ref)
521                 neigh_hold(n);
522         rcu_assign_pointer(n->next,
523                            rcu_dereference_protected(nht->hash_buckets[hash_val],
524                                                      lockdep_is_held(&tbl->lock)));
525         rcu_assign_pointer(nht->hash_buckets[hash_val], n);
526         write_unlock_bh(&tbl->lock);
527         neigh_dbg(2, "neigh %p is created\n", n);
528         rc = n;
529 out:
530         return rc;
531 out_tbl_unlock:
532         write_unlock_bh(&tbl->lock);
533 out_neigh_release:
534         neigh_release(n);
535         goto out;
536 }
537 EXPORT_SYMBOL(__neigh_create);
538 
539 static u32 pneigh_hash(const void *pkey, int key_len)
540 {
541         u32 hash_val = *(u32 *)(pkey + key_len - 4);
542         hash_val ^= (hash_val >> 16);
543         hash_val ^= hash_val >> 8;
544         hash_val ^= hash_val >> 4;
545         hash_val &= PNEIGH_HASHMASK;
546         return hash_val;
547 }
548 
549 static struct pneigh_entry *__pneigh_lookup_1(struct pneigh_entry *n,
550                                               struct net *net,
551                                               const void *pkey,
552                                               int key_len,
553                                               struct net_device *dev)
554 {
555         while (n) {
556                 if (!memcmp(n->key, pkey, key_len) &&
557                     net_eq(pneigh_net(n), net) &&
558                     (n->dev == dev || !n->dev))
559                         return n;
560                 n = n->next;
561         }
562         return NULL;
563 }
564 
565 struct pneigh_entry *__pneigh_lookup(struct neigh_table *tbl,
566                 struct net *net, const void *pkey, struct net_device *dev)
567 {
568         int key_len = tbl->key_len;
569         u32 hash_val = pneigh_hash(pkey, key_len);
570 
571         return __pneigh_lookup_1(tbl->phash_buckets[hash_val],
572                                  net, pkey, key_len, dev);
573 }
574 EXPORT_SYMBOL_GPL(__pneigh_lookup);
575 
576 struct pneigh_entry * pneigh_lookup(struct neigh_table *tbl,
577                                     struct net *net, const void *pkey,
578                                     struct net_device *dev, int creat)
579 {
580         struct pneigh_entry *n;
581         int key_len = tbl->key_len;
582         u32 hash_val = pneigh_hash(pkey, key_len);
583 
584         read_lock_bh(&tbl->lock);
585         n = __pneigh_lookup_1(tbl->phash_buckets[hash_val],
586                               net, pkey, key_len, dev);
587         read_unlock_bh(&tbl->lock);
588 
589         if (n || !creat)
590                 goto out;
591 
592         ASSERT_RTNL();
593 
594         n = kmalloc(sizeof(*n) + key_len, GFP_KERNEL);
595         if (!n)
596                 goto out;
597 
598         write_pnet(&n->net, net);
599         memcpy(n->key, pkey, key_len);
600         n->dev = dev;
601         if (dev)
602                 dev_hold(dev);
603 
604         if (tbl->pconstructor && tbl->pconstructor(n)) {
605                 if (dev)
606                         dev_put(dev);
607                 kfree(n);
608                 n = NULL;
609                 goto out;
610         }
611 
612         write_lock_bh(&tbl->lock);
613         n->next = tbl->phash_buckets[hash_val];
614         tbl->phash_buckets[hash_val] = n;
615         write_unlock_bh(&tbl->lock);
616 out:
617         return n;
618 }
619 EXPORT_SYMBOL(pneigh_lookup);
620 
621 
622 int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *pkey,
623                   struct net_device *dev)
624 {
625         struct pneigh_entry *n, **np;
626         int key_len = tbl->key_len;
627         u32 hash_val = pneigh_hash(pkey, key_len);
628 
629         write_lock_bh(&tbl->lock);
630         for (np = &tbl->phash_buckets[hash_val]; (n = *np) != NULL;
631              np = &n->next) {
632                 if (!memcmp(n->key, pkey, key_len) && n->dev == dev &&
633                     net_eq(pneigh_net(n), net)) {
634                         *np = n->next;
635                         write_unlock_bh(&tbl->lock);
636                         if (tbl->pdestructor)
637                                 tbl->pdestructor(n);
638                         if (n->dev)
639                                 dev_put(n->dev);
640                         kfree(n);
641                         return 0;
642                 }
643         }
644         write_unlock_bh(&tbl->lock);
645         return -ENOENT;
646 }
647 
648 static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev)
649 {
650         struct pneigh_entry *n, **np;
651         u32 h;
652 
653         for (h = 0; h <= PNEIGH_HASHMASK; h++) {
654                 np = &tbl->phash_buckets[h];
655                 while ((n = *np) != NULL) {
656                         if (!dev || n->dev == dev) {
657                                 *np = n->next;
658                                 if (tbl->pdestructor)
659                                         tbl->pdestructor(n);
660                                 if (n->dev)
661                                         dev_put(n->dev);
662                                 kfree(n);
663                                 continue;
664                         }
665                         np = &n->next;
666                 }
667         }
668         return -ENOENT;
669 }
670 
671 static void neigh_parms_destroy(struct neigh_parms *parms);
672 
673 static inline void neigh_parms_put(struct neigh_parms *parms)
674 {
675         if (atomic_dec_and_test(&parms->refcnt))
676                 neigh_parms_destroy(parms);
677 }
678 
679 /*
680  *      neighbour must already be out of the table;
681  *
682  */
683 void neigh_destroy(struct neighbour *neigh)
684 {
685         struct net_device *dev = neigh->dev;
686 
687         NEIGH_CACHE_STAT_INC(neigh->tbl, destroys);
688 
689         if (!neigh->dead) {
690                 pr_warn("Destroying alive neighbour %p\n", neigh);
691                 dump_stack();
692                 return;
693         }
694 
695         if (neigh_del_timer(neigh))
696                 pr_warn("Impossible event\n");
697 
698         write_lock_bh(&neigh->lock);
699         __skb_queue_purge(&neigh->arp_queue);
700         write_unlock_bh(&neigh->lock);
701         neigh->arp_queue_len_bytes = 0;
702 
703         if (dev->netdev_ops->ndo_neigh_destroy)
704                 dev->netdev_ops->ndo_neigh_destroy(neigh);
705 
706         dev_put(dev);
707         neigh_parms_put(neigh->parms);
708 
709         neigh_dbg(2, "neigh %p is destroyed\n", neigh);
710 
711         atomic_dec(&neigh->tbl->entries);
712         kfree_rcu(neigh, rcu);
713 }
714 EXPORT_SYMBOL(neigh_destroy);
715 
716 /* Neighbour state is suspicious;
717    disable fast path.
718 
719    Called with write_locked neigh.
720  */
721 static void neigh_suspect(struct neighbour *neigh)
722 {
723         neigh_dbg(2, "neigh %p is suspected\n", neigh);
724 
725         neigh->output = neigh->ops->output;
726 }
727 
728 /* Neighbour state is OK;
729    enable fast path.
730 
731    Called with write_locked neigh.
732  */
733 static void neigh_connect(struct neighbour *neigh)
734 {
735         neigh_dbg(2, "neigh %p is connected\n", neigh);
736 
737         neigh->output = neigh->ops->connected_output;
738 }
739 
740 static void neigh_periodic_work(struct work_struct *work)
741 {
742         struct neigh_table *tbl = container_of(work, struct neigh_table, gc_work.work);
743         struct neighbour *n;
744         struct neighbour __rcu **np;
745         unsigned int i;
746         struct neigh_hash_table *nht;
747 
748         NEIGH_CACHE_STAT_INC(tbl, periodic_gc_runs);
749 
750         write_lock_bh(&tbl->lock);
751         nht = rcu_dereference_protected(tbl->nht,
752                                         lockdep_is_held(&tbl->lock));
753 
754         /*
755          *      periodically recompute ReachableTime from random function
756          */
757 
758         if (time_after(jiffies, tbl->last_rand + 300 * HZ)) {
759                 struct neigh_parms *p;
760                 tbl->last_rand = jiffies;
761                 list_for_each_entry(p, &tbl->parms_list, list)
762                         p->reachable_time =
763                                 neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
764         }
765 
766         if (atomic_read(&tbl->entries) < tbl->gc_thresh1)
767                 goto out;
768 
769         for (i = 0 ; i < (1 << nht->hash_shift); i++) {
770                 np = &nht->hash_buckets[i];
771 
772                 while ((n = rcu_dereference_protected(*np,
773                                 lockdep_is_held(&tbl->lock))) != NULL) {
774                         unsigned int state;
775 
776                         write_lock(&n->lock);
777 
778                         state = n->nud_state;
779                         if (state & (NUD_PERMANENT | NUD_IN_TIMER)) {
780                                 write_unlock(&n->lock);
781                                 goto next_elt;
782                         }
783 
784                         if (time_before(n->used, n->confirmed))
785                                 n->used = n->confirmed;
786 
787                         if (atomic_read(&n->refcnt) == 1 &&
788                             (state == NUD_FAILED ||
789                              time_after(jiffies, n->used + NEIGH_VAR(n->parms, GC_STALETIME)))) {
790                                 *np = n->next;
791                                 n->dead = 1;
792                                 write_unlock(&n->lock);
793                                 neigh_cleanup_and_release(n);
794                                 continue;
795                         }
796                         write_unlock(&n->lock);
797 
798 next_elt:
799                         np = &n->next;
800                 }
801                 /*
802                  * It's fine to release lock here, even if hash table
803                  * grows while we are preempted.
804                  */
805                 write_unlock_bh(&tbl->lock);
806                 cond_resched();
807                 write_lock_bh(&tbl->lock);
808                 nht = rcu_dereference_protected(tbl->nht,
809                                                 lockdep_is_held(&tbl->lock));
810         }
811 out:
812         /* Cycle through all hash buckets every BASE_REACHABLE_TIME/2 ticks.
813          * ARP entry timeouts range from 1/2 BASE_REACHABLE_TIME to 3/2
814          * BASE_REACHABLE_TIME.
815          */
816         queue_delayed_work(system_power_efficient_wq, &tbl->gc_work,
817                               NEIGH_VAR(&tbl->parms, BASE_REACHABLE_TIME) >> 1);
818         write_unlock_bh(&tbl->lock);
819 }
820 
821 static __inline__ int neigh_max_probes(struct neighbour *n)
822 {
823         struct neigh_parms *p = n->parms;
824         return NEIGH_VAR(p, UCAST_PROBES) + NEIGH_VAR(p, APP_PROBES) +
825                (n->nud_state & NUD_PROBE ? NEIGH_VAR(p, MCAST_REPROBES) :
826                 NEIGH_VAR(p, MCAST_PROBES));
827 }
828 
829 static void neigh_invalidate(struct neighbour *neigh)
830         __releases(neigh->lock)
831         __acquires(neigh->lock)
832 {
833         struct sk_buff *skb;
834 
835         NEIGH_CACHE_STAT_INC(neigh->tbl, res_failed);
836         neigh_dbg(2, "neigh %p is failed\n", neigh);
837         neigh->updated = jiffies;
838 
839         /* It is very thin place. report_unreachable is very complicated
840            routine. Particularly, it can hit the same neighbour entry!
841 
842            So that, we try to be accurate and avoid dead loop. --ANK
843          */
844         while (neigh->nud_state == NUD_FAILED &&
845                (skb = __skb_dequeue(&neigh->arp_queue)) != NULL) {
846                 write_unlock(&neigh->lock);
847                 neigh->ops->error_report(neigh, skb);
848                 write_lock(&neigh->lock);
849         }
850         __skb_queue_purge(&neigh->arp_queue);
851         neigh->arp_queue_len_bytes = 0;
852 }
853 
854 static void neigh_probe(struct neighbour *neigh)
855         __releases(neigh->lock)
856 {
857         struct sk_buff *skb = skb_peek_tail(&neigh->arp_queue);
858         /* keep skb alive even if arp_queue overflows */
859         if (skb)
860                 skb = skb_copy(skb, GFP_ATOMIC);
861         write_unlock(&neigh->lock);
862         neigh->ops->solicit(neigh, skb);
863         atomic_inc(&neigh->probes);
864         kfree_skb(skb);
865 }
866 
867 /* Called when a timer expires for a neighbour entry. */
868 
869 static void neigh_timer_handler(unsigned long arg)
870 {
871         unsigned long now, next;
872         struct neighbour *neigh = (struct neighbour *)arg;
873         unsigned int state;
874         int notify = 0;
875 
876         write_lock(&neigh->lock);
877 
878         state = neigh->nud_state;
879         now = jiffies;
880         next = now + HZ;
881 
882         if (!(state & NUD_IN_TIMER))
883                 goto out;
884 
885         if (state & NUD_REACHABLE) {
886                 if (time_before_eq(now,
887                                    neigh->confirmed + neigh->parms->reachable_time)) {
888                         neigh_dbg(2, "neigh %p is still alive\n", neigh);
889                         next = neigh->confirmed + neigh->parms->reachable_time;
890                 } else if (time_before_eq(now,
891                                           neigh->used +
892                                           NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME))) {
893                         neigh_dbg(2, "neigh %p is delayed\n", neigh);
894                         neigh->nud_state = NUD_DELAY;
895                         neigh->updated = jiffies;
896                         neigh_suspect(neigh);
897                         next = now + NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME);
898                 } else {
899                         neigh_dbg(2, "neigh %p is suspected\n", neigh);
900                         neigh->nud_state = NUD_STALE;
901                         neigh->updated = jiffies;
902                         neigh_suspect(neigh);
903                         notify = 1;
904                 }
905         } else if (state & NUD_DELAY) {
906                 if (time_before_eq(now,
907                                    neigh->confirmed +
908                                    NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME))) {
909                         neigh_dbg(2, "neigh %p is now reachable\n", neigh);
910                         neigh->nud_state = NUD_REACHABLE;
911                         neigh->updated = jiffies;
912                         neigh_connect(neigh);
913                         notify = 1;
914                         next = neigh->confirmed + neigh->parms->reachable_time;
915                 } else {
916                         neigh_dbg(2, "neigh %p is probed\n", neigh);
917                         neigh->nud_state = NUD_PROBE;
918                         neigh->updated = jiffies;
919                         atomic_set(&neigh->probes, 0);
920                         notify = 1;
921                         next = now + NEIGH_VAR(neigh->parms, RETRANS_TIME);
922                 }
923         } else {
924                 /* NUD_PROBE|NUD_INCOMPLETE */
925                 next = now + NEIGH_VAR(neigh->parms, RETRANS_TIME);
926         }
927 
928         if ((neigh->nud_state & (NUD_INCOMPLETE | NUD_PROBE)) &&
929             atomic_read(&neigh->probes) >= neigh_max_probes(neigh)) {
930                 neigh->nud_state = NUD_FAILED;
931                 notify = 1;
932                 neigh_invalidate(neigh);
933                 goto out;
934         }
935 
936         if (neigh->nud_state & NUD_IN_TIMER) {
937                 if (time_before(next, jiffies + HZ/2))
938                         next = jiffies + HZ/2;
939                 if (!mod_timer(&neigh->timer, next))
940                         neigh_hold(neigh);
941         }
942         if (neigh->nud_state & (NUD_INCOMPLETE | NUD_PROBE)) {
943                 neigh_probe(neigh);
944         } else {
945 out:
946                 write_unlock(&neigh->lock);
947         }
948 
949         if (notify)
950                 neigh_update_notify(neigh);
951 
952         neigh_release(neigh);
953 }
954 
955 int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
956 {
957         int rc;
958         bool immediate_probe = false;
959 
960         write_lock_bh(&neigh->lock);
961 
962         rc = 0;
963         if (neigh->nud_state & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE))
964                 goto out_unlock_bh;
965         if (neigh->dead)
966                 goto out_dead;
967 
968         if (!(neigh->nud_state & (NUD_STALE | NUD_INCOMPLETE))) {
969                 if (NEIGH_VAR(neigh->parms, MCAST_PROBES) +
970                     NEIGH_VAR(neigh->parms, APP_PROBES)) {
971                         unsigned long next, now = jiffies;
972 
973                         atomic_set(&neigh->probes,
974                                    NEIGH_VAR(neigh->parms, UCAST_PROBES));
975                         neigh->nud_state     = NUD_INCOMPLETE;
976                         neigh->updated = now;
977                         next = now + max(NEIGH_VAR(neigh->parms, RETRANS_TIME),
978                                          HZ/2);
979                         neigh_add_timer(neigh, next);
980                         immediate_probe = true;
981                 } else {
982                         neigh->nud_state = NUD_FAILED;
983                         neigh->updated = jiffies;
984                         write_unlock_bh(&neigh->lock);
985 
986                         kfree_skb(skb);
987                         return 1;
988                 }
989         } else if (neigh->nud_state & NUD_STALE) {
990                 neigh_dbg(2, "neigh %p is delayed\n", neigh);
991                 neigh->nud_state = NUD_DELAY;
992                 neigh->updated = jiffies;
993                 neigh_add_timer(neigh, jiffies +
994                                 NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME));
995         }
996 
997         if (neigh->nud_state == NUD_INCOMPLETE) {
998                 if (skb) {
999                         while (neigh->arp_queue_len_bytes + skb->truesize >
1000                                NEIGH_VAR(neigh->parms, QUEUE_LEN_BYTES)) {
1001                                 struct sk_buff *buff;
1002 
1003                                 buff = __skb_dequeue(&neigh->arp_queue);
1004                                 if (!buff)
1005                                         break;
1006                                 neigh->arp_queue_len_bytes -= buff->truesize;
1007                                 kfree_skb(buff);
1008                                 NEIGH_CACHE_STAT_INC(neigh->tbl, unres_discards);
1009                         }
1010                         skb_dst_force(skb);
1011                         __skb_queue_tail(&neigh->arp_queue, skb);
1012                         neigh->arp_queue_len_bytes += skb->truesize;
1013                 }
1014                 rc = 1;
1015         }
1016 out_unlock_bh:
1017         if (immediate_probe)
1018                 neigh_probe(neigh);
1019         else
1020                 write_unlock(&neigh->lock);
1021         local_bh_enable();
1022         return rc;
1023 
1024 out_dead:
1025         if (neigh->nud_state & NUD_STALE)
1026                 goto out_unlock_bh;
1027         write_unlock_bh(&neigh->lock);
1028         kfree_skb(skb);
1029         return 1;
1030 }
1031 EXPORT_SYMBOL(__neigh_event_send);
1032 
1033 static void neigh_update_hhs(struct neighbour *neigh)
1034 {
1035         struct hh_cache *hh;
1036         void (*update)(struct hh_cache*, const struct net_device*, const unsigned char *)
1037                 = NULL;
1038 
1039         if (neigh->dev->header_ops)
1040                 update = neigh->dev->header_ops->cache_update;
1041 
1042         if (update) {
1043                 hh = &neigh->hh;
1044                 if (hh->hh_len) {
1045                         write_seqlock_bh(&hh->hh_lock);
1046                         update(hh, neigh->dev, neigh->ha);
1047                         write_sequnlock_bh(&hh->hh_lock);
1048                 }
1049         }
1050 }
1051 
1052 
1053 
1054 /* Generic update routine.
1055    -- lladdr is new lladdr or NULL, if it is not supplied.
1056    -- new    is new state.
1057    -- flags
1058         NEIGH_UPDATE_F_OVERRIDE allows to override existing lladdr,
1059                                 if it is different.
1060         NEIGH_UPDATE_F_WEAK_OVERRIDE will suspect existing "connected"
1061                                 lladdr instead of overriding it
1062                                 if it is different.
1063                                 It also allows to retain current state
1064                                 if lladdr is unchanged.
1065         NEIGH_UPDATE_F_ADMIN    means that the change is administrative.
1066 
1067         NEIGH_UPDATE_F_OVERRIDE_ISROUTER allows to override existing
1068                                 NTF_ROUTER flag.
1069         NEIGH_UPDATE_F_ISROUTER indicates if the neighbour is known as
1070                                 a router.
1071 
1072    Caller MUST hold reference count on the entry.
1073  */
1074 
1075 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
1076                  u32 flags)
1077 {
1078         u8 old;
1079         int err;
1080         int notify = 0;
1081         struct net_device *dev;
1082         int update_isrouter = 0;
1083 
1084         write_lock_bh(&neigh->lock);
1085 
1086         dev    = neigh->dev;
1087         old    = neigh->nud_state;
1088         err    = -EPERM;
1089 
1090         if (!(flags & NEIGH_UPDATE_F_ADMIN) &&
1091             (old & (NUD_NOARP | NUD_PERMANENT)))
1092                 goto out;
1093         if (neigh->dead)
1094                 goto out;
1095 
1096         if (!(new & NUD_VALID)) {
1097                 neigh_del_timer(neigh);
1098                 if (old & NUD_CONNECTED)
1099                         neigh_suspect(neigh);
1100                 neigh->nud_state = new;
1101                 err = 0;
1102                 notify = old & NUD_VALID;
1103                 if ((old & (NUD_INCOMPLETE | NUD_PROBE)) &&
1104                     (new & NUD_FAILED)) {
1105                         neigh_invalidate(neigh);
1106                         notify = 1;
1107                 }
1108                 goto out;
1109         }
1110 
1111         /* Compare new lladdr with cached one */
1112         if (!dev->addr_len) {
1113                 /* First case: device needs no address. */
1114                 lladdr = neigh->ha;
1115         } else if (lladdr) {
1116                 /* The second case: if something is already cached
1117                    and a new address is proposed:
1118                    - compare new & old
1119                    - if they are different, check override flag
1120                  */
1121                 if ((old & NUD_VALID) &&
1122                     !memcmp(lladdr, neigh->ha, dev->addr_len))
1123                         lladdr = neigh->ha;
1124         } else {
1125                 /* No address is supplied; if we know something,
1126                    use it, otherwise discard the request.
1127                  */
1128                 err = -EINVAL;
1129                 if (!(old & NUD_VALID))
1130                         goto out;
1131                 lladdr = neigh->ha;
1132         }
1133 
1134         if (new & NUD_CONNECTED)
1135                 neigh->confirmed = jiffies;
1136         neigh->updated = jiffies;
1137 
1138         /* If entry was valid and address is not changed,
1139            do not change entry state, if new one is STALE.
1140          */
1141         err = 0;
1142         update_isrouter = flags & NEIGH_UPDATE_F_OVERRIDE_ISROUTER;
1143         if (old & NUD_VALID) {
1144                 if (lladdr != neigh->ha && !(flags & NEIGH_UPDATE_F_OVERRIDE)) {
1145                         update_isrouter = 0;
1146                         if ((flags & NEIGH_UPDATE_F_WEAK_OVERRIDE) &&
1147                             (old & NUD_CONNECTED)) {
1148                                 lladdr = neigh->ha;
1149                                 new = NUD_STALE;
1150                         } else
1151                                 goto out;
1152                 } else {
1153                         if (lladdr == neigh->ha && new == NUD_STALE &&
1154                             ((flags & NEIGH_UPDATE_F_WEAK_OVERRIDE) ||
1155                              (old & NUD_CONNECTED))
1156                             )
1157                                 new = old;
1158                 }
1159         }
1160 
1161         if (new != old) {
1162                 neigh_del_timer(neigh);
1163                 if (new & NUD_PROBE)
1164                         atomic_set(&neigh->probes, 0);
1165                 if (new & NUD_IN_TIMER)
1166                         neigh_add_timer(neigh, (jiffies +
1167                                                 ((new & NUD_REACHABLE) ?
1168                                                  neigh->parms->reachable_time :
1169                                                  0)));
1170                 neigh->nud_state = new;
1171                 notify = 1;
1172         }
1173 
1174         if (lladdr != neigh->ha) {
1175                 write_seqlock(&neigh->ha_lock);
1176                 memcpy(&neigh->ha, lladdr, dev->addr_len);
1177                 write_sequnlock(&neigh->ha_lock);
1178                 neigh_update_hhs(neigh);
1179                 if (!(new & NUD_CONNECTED))
1180                         neigh->confirmed = jiffies -
1181                                       (NEIGH_VAR(neigh->parms, BASE_REACHABLE_TIME) << 1);
1182                 notify = 1;
1183         }
1184         if (new == old)
1185                 goto out;
1186         if (new & NUD_CONNECTED)
1187                 neigh_connect(neigh);
1188         else
1189                 neigh_suspect(neigh);
1190         if (!(old & NUD_VALID)) {
1191                 struct sk_buff *skb;
1192 
1193                 /* Again: avoid dead loop if something went wrong */
1194 
1195                 while (neigh->nud_state & NUD_VALID &&
1196                        (skb = __skb_dequeue(&neigh->arp_queue)) != NULL) {
1197                         struct dst_entry *dst = skb_dst(skb);
1198                         struct neighbour *n2, *n1 = neigh;
1199                         write_unlock_bh(&neigh->lock);
1200 
1201                         rcu_read_lock();
1202 
1203                         /* Why not just use 'neigh' as-is?  The problem is that
1204                          * things such as shaper, eql, and sch_teql can end up
1205                          * using alternative, different, neigh objects to output
1206                          * the packet in the output path.  So what we need to do
1207                          * here is re-lookup the top-level neigh in the path so
1208                          * we can reinject the packet there.
1209                          */
1210                         n2 = NULL;
1211                         if (dst) {
1212                                 n2 = dst_neigh_lookup_skb(dst, skb);
1213                                 if (n2)
1214                                         n1 = n2;
1215                         }
1216                         n1->output(n1, skb);
1217                         if (n2)
1218                                 neigh_release(n2);
1219                         rcu_read_unlock();
1220 
1221                         write_lock_bh(&neigh->lock);
1222                 }
1223                 __skb_queue_purge(&neigh->arp_queue);
1224                 neigh->arp_queue_len_bytes = 0;
1225         }
1226 out:
1227         if (update_isrouter) {
1228                 neigh->flags = (flags & NEIGH_UPDATE_F_ISROUTER) ?
1229                         (neigh->flags | NTF_ROUTER) :
1230                         (neigh->flags & ~NTF_ROUTER);
1231         }
1232         write_unlock_bh(&neigh->lock);
1233 
1234         if (notify)
1235                 neigh_update_notify(neigh);
1236 
1237         return err;
1238 }
1239 EXPORT_SYMBOL(neigh_update);
1240 
1241 /* Update the neigh to listen temporarily for probe responses, even if it is
1242  * in a NUD_FAILED state. The caller has to hold neigh->lock for writing.
1243  */
1244 void __neigh_set_probe_once(struct neighbour *neigh)
1245 {
1246         if (neigh->dead)
1247                 return;
1248         neigh->updated = jiffies;
1249         if (!(neigh->nud_state & NUD_FAILED))
1250                 return;
1251         neigh->nud_state = NUD_INCOMPLETE;
1252         atomic_set(&neigh->probes, neigh_max_probes(neigh));
1253         neigh_add_timer(neigh,
1254                         jiffies + NEIGH_VAR(neigh->parms, RETRANS_TIME));
1255 }
1256 EXPORT_SYMBOL(__neigh_set_probe_once);
1257 
1258 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
1259                                  u8 *lladdr, void *saddr,
1260                                  struct net_device *dev)
1261 {
1262         struct neighbour *neigh = __neigh_lookup(tbl, saddr, dev,
1263                                                  lladdr || !dev->addr_len);
1264         if (neigh)
1265                 neigh_update(neigh, lladdr, NUD_STALE,
1266                              NEIGH_UPDATE_F_OVERRIDE);
1267         return neigh;
1268 }
1269 EXPORT_SYMBOL(neigh_event_ns);
1270 
1271 /* called with read_lock_bh(&n->lock); */
1272 static void neigh_hh_init(struct neighbour *n)
1273 {
1274         struct net_device *dev = n->dev;
1275         __be16 prot = n->tbl->protocol;
1276         struct hh_cache *hh = &n->hh;
1277 
1278         write_lock_bh(&n->lock);
1279 
1280         /* Only one thread can come in here and initialize the
1281          * hh_cache entry.
1282          */
1283         if (!hh->hh_len)
1284                 dev->header_ops->cache(n, hh, prot);
1285 
1286         write_unlock_bh(&n->lock);
1287 }
1288 
1289 /* Slow and careful. */
1290 
1291 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb)
1292 {
1293         int rc = 0;
1294 
1295         if (!neigh_event_send(neigh, skb)) {
1296                 int err;
1297                 struct net_device *dev = neigh->dev;
1298                 unsigned int seq;
1299 
1300                 if (dev->header_ops->cache && !neigh->hh.hh_len)
1301                         neigh_hh_init(neigh);
1302 
1303                 do {
1304                         __skb_pull(skb, skb_network_offset(skb));
1305                         seq = read_seqbegin(&neigh->ha_lock);
1306                         err = dev_hard_header(skb, dev, ntohs(skb->protocol),
1307                                               neigh->ha, NULL, skb->len);
1308                 } while (read_seqretry(&neigh->ha_lock, seq));
1309 
1310                 if (err >= 0)
1311                         rc = dev_queue_xmit(skb);
1312                 else
1313                         goto out_kfree_skb;
1314         }
1315 out:
1316         return rc;
1317 out_kfree_skb:
1318         rc = -EINVAL;
1319         kfree_skb(skb);
1320         goto out;
1321 }
1322 EXPORT_SYMBOL(neigh_resolve_output);
1323 
1324 /* As fast as possible without hh cache */
1325 
1326 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb)
1327 {
1328         struct net_device *dev = neigh->dev;
1329         unsigned int seq;
1330         int err;
1331 
1332         do {
1333                 __skb_pull(skb, skb_network_offset(skb));
1334                 seq = read_seqbegin(&neigh->ha_lock);
1335                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
1336                                       neigh->ha, NULL, skb->len);
1337         } while (read_seqretry(&neigh->ha_lock, seq));
1338 
1339         if (err >= 0)
1340                 err = dev_queue_xmit(skb);
1341         else {
1342                 err = -EINVAL;
1343                 kfree_skb(skb);
1344         }
1345         return err;
1346 }
1347 EXPORT_SYMBOL(neigh_connected_output);
1348 
1349 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb)
1350 {
1351         return dev_queue_xmit(skb);
1352 }
1353 EXPORT_SYMBOL(neigh_direct_output);
1354 
1355 static void neigh_proxy_process(unsigned long arg)
1356 {
1357         struct neigh_table *tbl = (struct neigh_table *)arg;
1358         long sched_next = 0;
1359         unsigned long now = jiffies;
1360         struct sk_buff *skb, *n;
1361 
1362         spin_lock(&tbl->proxy_queue.lock);
1363 
1364         skb_queue_walk_safe(&tbl->proxy_queue, skb, n) {
1365                 long tdif = NEIGH_CB(skb)->sched_next - now;
1366 
1367                 if (tdif <= 0) {
1368                         struct net_device *dev = skb->dev;
1369 
1370                         __skb_unlink(skb, &tbl->proxy_queue);
1371                         if (tbl->proxy_redo && netif_running(dev)) {
1372                                 rcu_read_lock();
1373                                 tbl->proxy_redo(skb);
1374                                 rcu_read_unlock();
1375                         } else {
1376                                 kfree_skb(skb);
1377                         }
1378 
1379                         dev_put(dev);
1380                 } else if (!sched_next || tdif < sched_next)
1381                         sched_next = tdif;
1382         }
1383         del_timer(&tbl->proxy_timer);
1384         if (sched_next)
1385                 mod_timer(&tbl->proxy_timer, jiffies + sched_next);
1386         spin_unlock(&tbl->proxy_queue.lock);
1387 }
1388 
1389 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
1390                     struct sk_buff *skb)
1391 {
1392         unsigned long now = jiffies;
1393 
1394         unsigned long sched_next = now + (prandom_u32() %
1395                                           NEIGH_VAR(p, PROXY_DELAY));
1396 
1397         if (tbl->proxy_queue.qlen > NEIGH_VAR(p, PROXY_QLEN)) {
1398                 kfree_skb(skb);
1399                 return;
1400         }
1401 
1402         NEIGH_CB(skb)->sched_next = sched_next;
1403         NEIGH_CB(skb)->flags |= LOCALLY_ENQUEUED;
1404 
1405         spin_lock(&tbl->proxy_queue.lock);
1406         if (del_timer(&tbl->proxy_timer)) {
1407                 if (time_before(tbl->proxy_timer.expires, sched_next))
1408                         sched_next = tbl->proxy_timer.expires;
1409         }
1410         skb_dst_drop(skb);
1411         dev_hold(skb->dev);
1412         __skb_queue_tail(&tbl->proxy_queue, skb);
1413         mod_timer(&tbl->proxy_timer, sched_next);
1414         spin_unlock(&tbl->proxy_queue.lock);
1415 }
1416 EXPORT_SYMBOL(pneigh_enqueue);
1417 
1418 static inline struct neigh_parms *lookup_neigh_parms(struct neigh_table *tbl,
1419                                                       struct net *net, int ifindex)
1420 {
1421         struct neigh_parms *p;
1422 
1423         list_for_each_entry(p, &tbl->parms_list, list) {
1424                 if ((p->dev && p->dev->ifindex == ifindex && net_eq(neigh_parms_net(p), net)) ||
1425                     (!p->dev && !ifindex && net_eq(net, &init_net)))
1426                         return p;
1427         }
1428 
1429         return NULL;
1430 }
1431 
1432 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
1433                                       struct neigh_table *tbl)
1434 {
1435         struct neigh_parms *p;
1436         struct net *net = dev_net(dev);
1437         const struct net_device_ops *ops = dev->netdev_ops;
1438 
1439         p = kmemdup(&tbl->parms, sizeof(*p), GFP_KERNEL);
1440         if (p) {
1441                 p->tbl            = tbl;
1442                 atomic_set(&p->refcnt, 1);
1443                 p->reachable_time =
1444                                 neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
1445                 dev_hold(dev);
1446                 p->dev = dev;
1447                 write_pnet(&p->net, net);
1448                 p->sysctl_table = NULL;
1449 
1450                 if (ops->ndo_neigh_setup && ops->ndo_neigh_setup(dev, p)) {
1451                         dev_put(dev);
1452                         kfree(p);
1453                         return NULL;
1454                 }
1455 
1456                 write_lock_bh(&tbl->lock);
1457                 list_add(&p->list, &tbl->parms.list);
1458                 write_unlock_bh(&tbl->lock);
1459 
1460                 neigh_parms_data_state_cleanall(p);
1461         }
1462         return p;
1463 }
1464 EXPORT_SYMBOL(neigh_parms_alloc);
1465 
1466 static void neigh_rcu_free_parms(struct rcu_head *head)
1467 {
1468         struct neigh_parms *parms =
1469                 container_of(head, struct neigh_parms, rcu_head);
1470 
1471         neigh_parms_put(parms);
1472 }
1473 
1474 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms)
1475 {
1476         if (!parms || parms == &tbl->parms)
1477                 return;
1478         write_lock_bh(&tbl->lock);
1479         list_del(&parms->list);
1480         parms->dead = 1;
1481         write_unlock_bh(&tbl->lock);
1482         if (parms->dev)
1483                 dev_put(parms->dev);
1484         call_rcu(&parms->rcu_head, neigh_rcu_free_parms);
1485 }
1486 EXPORT_SYMBOL(neigh_parms_release);
1487 
1488 static void neigh_parms_destroy(struct neigh_parms *parms)
1489 {
1490         kfree(parms);
1491 }
1492 
1493 static struct lock_class_key neigh_table_proxy_queue_class;
1494 
1495 static struct neigh_table *neigh_tables[NEIGH_NR_TABLES] __read_mostly;
1496 
1497 void neigh_table_init(int index, struct neigh_table *tbl)
1498 {
1499         unsigned long now = jiffies;
1500         unsigned long phsize;
1501 
1502         INIT_LIST_HEAD(&tbl->parms_list);
1503         list_add(&tbl->parms.list, &tbl->parms_list);
1504         write_pnet(&tbl->parms.net, &init_net);
1505         atomic_set(&tbl->parms.refcnt, 1);
1506         tbl->parms.reachable_time =
1507                           neigh_rand_reach_time(NEIGH_VAR(&tbl->parms, BASE_REACHABLE_TIME));
1508 
1509         tbl->stats = alloc_percpu(struct neigh_statistics);
1510         if (!tbl->stats)
1511                 panic("cannot create neighbour cache statistics");
1512 
1513 #ifdef CONFIG_PROC_FS
1514         if (!proc_create_data(tbl->id, 0, init_net.proc_net_stat,
1515                               &neigh_stat_seq_fops, tbl))
1516                 panic("cannot create neighbour proc dir entry");
1517 #endif
1518 
1519         RCU_INIT_POINTER(tbl->nht, neigh_hash_alloc(3));
1520 
1521         phsize = (PNEIGH_HASHMASK + 1) * sizeof(struct pneigh_entry *);
1522         tbl->phash_buckets = kzalloc(phsize, GFP_KERNEL);
1523 
1524         if (!tbl->nht || !tbl->phash_buckets)
1525                 panic("cannot allocate neighbour cache hashes");
1526 
1527         if (!tbl->entry_size)
1528                 tbl->entry_size = ALIGN(offsetof(struct neighbour, primary_key) +
1529                                         tbl->key_len, NEIGH_PRIV_ALIGN);
1530         else
1531                 WARN_ON(tbl->entry_size % NEIGH_PRIV_ALIGN);
1532 
1533         rwlock_init(&tbl->lock);
1534         INIT_DEFERRABLE_WORK(&tbl->gc_work, neigh_periodic_work);
1535         queue_delayed_work(system_power_efficient_wq, &tbl->gc_work,
1536                         tbl->parms.reachable_time);
1537         setup_timer(&tbl->proxy_timer, neigh_proxy_process, (unsigned long)tbl);
1538         skb_queue_head_init_class(&tbl->proxy_queue,
1539                         &neigh_table_proxy_queue_class);
1540 
1541         tbl->last_flush = now;
1542         tbl->last_rand  = now + tbl->parms.reachable_time * 20;
1543 
1544         neigh_tables[index] = tbl;
1545 }
1546 EXPORT_SYMBOL(neigh_table_init);
1547 
1548 int neigh_table_clear(int index, struct neigh_table *tbl)
1549 {
1550         neigh_tables[index] = NULL;
1551         /* It is not clean... Fix it to unload IPv6 module safely */
1552         cancel_delayed_work_sync(&tbl->gc_work);
1553         del_timer_sync(&tbl->proxy_timer);
1554         pneigh_queue_purge(&tbl->proxy_queue);
1555         neigh_ifdown(tbl, NULL);
1556         if (atomic_read(&tbl->entries))
1557                 pr_crit("neighbour leakage\n");
1558 
1559         call_rcu(&rcu_dereference_protected(tbl->nht, 1)->rcu,
1560                  neigh_hash_free_rcu);
1561         tbl->nht = NULL;
1562 
1563         kfree(tbl->phash_buckets);
1564         tbl->phash_buckets = NULL;
1565 
1566         remove_proc_entry(tbl->id, init_net.proc_net_stat);
1567 
1568         free_percpu(tbl->stats);
1569         tbl->stats = NULL;
1570 
1571         return 0;
1572 }
1573 EXPORT_SYMBOL(neigh_table_clear);
1574 
1575 static struct neigh_table *neigh_find_table(int family)
1576 {
1577         struct neigh_table *tbl = NULL;
1578 
1579         switch (family) {
1580         case AF_INET:
1581                 tbl = neigh_tables[NEIGH_ARP_TABLE];
1582                 break;
1583         case AF_INET6:
1584                 tbl = neigh_tables[NEIGH_ND_TABLE];
1585                 break;
1586         case AF_DECnet:
1587                 tbl = neigh_tables[NEIGH_DN_TABLE];
1588                 break;
1589         }
1590 
1591         return tbl;
1592 }
1593 
1594 static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh)
1595 {
1596         struct net *net = sock_net(skb->sk);
1597         struct ndmsg *ndm;
1598         struct nlattr *dst_attr;
1599         struct neigh_table *tbl;
1600         struct neighbour *neigh;
1601         struct net_device *dev = NULL;
1602         int err = -EINVAL;
1603 
1604         ASSERT_RTNL();
1605         if (nlmsg_len(nlh) < sizeof(*ndm))
1606                 goto out;
1607 
1608         dst_attr = nlmsg_find_attr(nlh, sizeof(*ndm), NDA_DST);
1609         if (dst_attr == NULL)
1610                 goto out;
1611 
1612         ndm = nlmsg_data(nlh);
1613         if (ndm->ndm_ifindex) {
1614                 dev = __dev_get_by_index(net, ndm->ndm_ifindex);
1615                 if (dev == NULL) {
1616                         err = -ENODEV;
1617                         goto out;
1618                 }
1619         }
1620 
1621         tbl = neigh_find_table(ndm->ndm_family);
1622         if (tbl == NULL)
1623                 return -EAFNOSUPPORT;
1624 
1625         if (nla_len(dst_attr) < tbl->key_len)
1626                 goto out;
1627 
1628         if (ndm->ndm_flags & NTF_PROXY) {
1629                 err = pneigh_delete(tbl, net, nla_data(dst_attr), dev);
1630                 goto out;
1631         }
1632 
1633         if (dev == NULL)
1634                 goto out;
1635 
1636         neigh = neigh_lookup(tbl, nla_data(dst_attr), dev);
1637         if (neigh == NULL) {
1638                 err = -ENOENT;
1639                 goto out;
1640         }
1641 
1642         err = neigh_update(neigh, NULL, NUD_FAILED,
1643                            NEIGH_UPDATE_F_OVERRIDE |
1644                            NEIGH_UPDATE_F_ADMIN);
1645         neigh_release(neigh);
1646 
1647 out:
1648         return err;
1649 }
1650 
1651 static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh)
1652 {
1653         int flags = NEIGH_UPDATE_F_ADMIN | NEIGH_UPDATE_F_OVERRIDE;
1654         struct net *net = sock_net(skb->sk);
1655         struct ndmsg *ndm;
1656         struct nlattr *tb[NDA_MAX+1];
1657         struct neigh_table *tbl;
1658         struct net_device *dev = NULL;
1659         struct neighbour *neigh;
1660         void *dst, *lladdr;
1661         int err;
1662 
1663         ASSERT_RTNL();
1664         err = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, NULL);
1665         if (err < 0)
1666                 goto out;
1667 
1668         err = -EINVAL;
1669         if (tb[NDA_DST] == NULL)
1670                 goto out;
1671 
1672         ndm = nlmsg_data(nlh);
1673         if (ndm->ndm_ifindex) {
1674                 dev = __dev_get_by_index(net, ndm->ndm_ifindex);
1675                 if (dev == NULL) {
1676                         err = -ENODEV;
1677                         goto out;
1678                 }
1679 
1680                 if (tb[NDA_LLADDR] && nla_len(tb[NDA_LLADDR]) < dev->addr_len)
1681                         goto out;
1682         }
1683 
1684         tbl = neigh_find_table(ndm->ndm_family);
1685         if (tbl == NULL)
1686                 return -EAFNOSUPPORT;
1687 
1688         if (nla_len(tb[NDA_DST]) < tbl->key_len)
1689                 goto out;
1690         dst = nla_data(tb[NDA_DST]);
1691         lladdr = tb[NDA_LLADDR] ? nla_data(tb[NDA_LLADDR]) : NULL;
1692 
1693         if (ndm->ndm_flags & NTF_PROXY) {
1694                 struct pneigh_entry *pn;
1695 
1696                 err = -ENOBUFS;
1697                 pn = pneigh_lookup(tbl, net, dst, dev, 1);
1698                 if (pn) {
1699                         pn->flags = ndm->ndm_flags;
1700                         err = 0;
1701                 }
1702                 goto out;
1703         }
1704 
1705         if (dev == NULL)
1706                 goto out;
1707 
1708         neigh = neigh_lookup(tbl, dst, dev);
1709         if (neigh == NULL) {
1710                 if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
1711                         err = -ENOENT;
1712                         goto out;
1713                 }
1714 
1715                 neigh = __neigh_lookup_errno(tbl, dst, dev);
1716                 if (IS_ERR(neigh)) {
1717                         err = PTR_ERR(neigh);
1718                         goto out;
1719                 }
1720         } else {
1721                 if (nlh->nlmsg_flags & NLM_F_EXCL) {
1722                         err = -EEXIST;
1723                         neigh_release(neigh);
1724                         goto out;
1725                 }
1726 
1727                 if (!(nlh->nlmsg_flags & NLM_F_REPLACE))
1728                         flags &= ~NEIGH_UPDATE_F_OVERRIDE;
1729         }
1730 
1731         if (ndm->ndm_flags & NTF_USE) {
1732                 neigh_event_send(neigh, NULL);
1733                 err = 0;
1734         } else
1735                 err = neigh_update(neigh, lladdr, ndm->ndm_state, flags);
1736         neigh_release(neigh);
1737 
1738 out:
1739         return err;
1740 }
1741 
1742 static int neightbl_fill_parms(struct sk_buff *skb, struct neigh_parms *parms)
1743 {
1744         struct nlattr *nest;
1745 
1746         nest = nla_nest_start(skb, NDTA_PARMS);
1747         if (nest == NULL)
1748                 return -ENOBUFS;
1749 
1750         if ((parms->dev &&
1751              nla_put_u32(skb, NDTPA_IFINDEX, parms->dev->ifindex)) ||
1752             nla_put_u32(skb, NDTPA_REFCNT, atomic_read(&parms->refcnt)) ||
1753             nla_put_u32(skb, NDTPA_QUEUE_LENBYTES,
1754                         NEIGH_VAR(parms, QUEUE_LEN_BYTES)) ||
1755             /* approximative value for deprecated QUEUE_LEN (in packets) */
1756             nla_put_u32(skb, NDTPA_QUEUE_LEN,
1757                         NEIGH_VAR(parms, QUEUE_LEN_BYTES) / SKB_TRUESIZE(ETH_FRAME_LEN)) ||
1758             nla_put_u32(skb, NDTPA_PROXY_QLEN, NEIGH_VAR(parms, PROXY_QLEN)) ||
1759             nla_put_u32(skb, NDTPA_APP_PROBES, NEIGH_VAR(parms, APP_PROBES)) ||
1760             nla_put_u32(skb, NDTPA_UCAST_PROBES,
1761                         NEIGH_VAR(parms, UCAST_PROBES)) ||
1762             nla_put_u32(skb, NDTPA_MCAST_PROBES,
1763                         NEIGH_VAR(parms, MCAST_PROBES)) ||
1764             nla_put_u32(skb, NDTPA_MCAST_REPROBES,
1765                         NEIGH_VAR(parms, MCAST_REPROBES)) ||
1766             nla_put_msecs(skb, NDTPA_REACHABLE_TIME, parms->reachable_time) ||
1767             nla_put_msecs(skb, NDTPA_BASE_REACHABLE_TIME,
1768                           NEIGH_VAR(parms, BASE_REACHABLE_TIME)) ||
1769             nla_put_msecs(skb, NDTPA_GC_STALETIME,
1770                           NEIGH_VAR(parms, GC_STALETIME)) ||
1771             nla_put_msecs(skb, NDTPA_DELAY_PROBE_TIME,
1772                           NEIGH_VAR(parms, DELAY_PROBE_TIME)) ||
1773             nla_put_msecs(skb, NDTPA_RETRANS_TIME,
1774                           NEIGH_VAR(parms, RETRANS_TIME)) ||
1775             nla_put_msecs(skb, NDTPA_ANYCAST_DELAY,
1776                           NEIGH_VAR(parms, ANYCAST_DELAY)) ||
1777             nla_put_msecs(skb, NDTPA_PROXY_DELAY,
1778                           NEIGH_VAR(parms, PROXY_DELAY)) ||
1779             nla_put_msecs(skb, NDTPA_LOCKTIME,
1780                           NEIGH_VAR(parms, LOCKTIME)))
1781                 goto nla_put_failure;
1782         return nla_nest_end(skb, nest);
1783 
1784 nla_put_failure:
1785         nla_nest_cancel(skb, nest);
1786         return -EMSGSIZE;
1787 }
1788 
1789 static int neightbl_fill_info(struct sk_buff *skb, struct neigh_table *tbl,
1790                               u32 pid, u32 seq, int type, int flags)
1791 {
1792         struct nlmsghdr *nlh;
1793         struct ndtmsg *ndtmsg;
1794 
1795         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndtmsg), flags);
1796         if (nlh == NULL)
1797                 return -EMSGSIZE;
1798 
1799         ndtmsg = nlmsg_data(nlh);
1800 
1801         read_lock_bh(&tbl->lock);
1802         ndtmsg->ndtm_family = tbl->family;
1803         ndtmsg->ndtm_pad1   = 0;
1804         ndtmsg->ndtm_pad2   = 0;
1805 
1806         if (nla_put_string(skb, NDTA_NAME, tbl->id) ||
1807             nla_put_msecs(skb, NDTA_GC_INTERVAL, tbl->gc_interval) ||
1808             nla_put_u32(skb, NDTA_THRESH1, tbl->gc_thresh1) ||
1809             nla_put_u32(skb, NDTA_THRESH2, tbl->gc_thresh2) ||
1810             nla_put_u32(skb, NDTA_THRESH3, tbl->gc_thresh3))
1811                 goto nla_put_failure;
1812         {
1813                 unsigned long now = jiffies;
1814                 unsigned int flush_delta = now - tbl->last_flush;
1815                 unsigned int rand_delta = now - tbl->last_rand;
1816                 struct neigh_hash_table *nht;
1817                 struct ndt_config ndc = {
1818                         .ndtc_key_len           = tbl->key_len,
1819                         .ndtc_entry_size        = tbl->entry_size,
1820                         .ndtc_entries           = atomic_read(&tbl->entries),
1821                         .ndtc_last_flush        = jiffies_to_msecs(flush_delta),
1822                         .ndtc_last_rand         = jiffies_to_msecs(rand_delta),
1823                         .ndtc_proxy_qlen        = tbl->proxy_queue.qlen,
1824                 };
1825 
1826                 rcu_read_lock_bh();
1827                 nht = rcu_dereference_bh(tbl->nht);
1828                 ndc.ndtc_hash_rnd = nht->hash_rnd[0];
1829                 ndc.ndtc_hash_mask = ((1 << nht->hash_shift) - 1);
1830                 rcu_read_unlock_bh();
1831 
1832                 if (nla_put(skb, NDTA_CONFIG, sizeof(ndc), &ndc))
1833                         goto nla_put_failure;
1834         }
1835 
1836         {
1837                 int cpu;
1838                 struct ndt_stats ndst;
1839 
1840                 memset(&ndst, 0, sizeof(ndst));
1841 
1842                 for_each_possible_cpu(cpu) {
1843                         struct neigh_statistics *st;
1844 
1845                         st = per_cpu_ptr(tbl->stats, cpu);
1846                         ndst.ndts_allocs                += st->allocs;
1847                         ndst.ndts_destroys              += st->destroys;
1848                         ndst.ndts_hash_grows            += st->hash_grows;
1849                         ndst.ndts_res_failed            += st->res_failed;
1850                         ndst.ndts_lookups               += st->lookups;
1851                         ndst.ndts_hits                  += st->hits;
1852                         ndst.ndts_rcv_probes_mcast      += st->rcv_probes_mcast;
1853                         ndst.ndts_rcv_probes_ucast      += st->rcv_probes_ucast;
1854                         ndst.ndts_periodic_gc_runs      += st->periodic_gc_runs;
1855                         ndst.ndts_forced_gc_runs        += st->forced_gc_runs;
1856                         ndst.ndts_table_fulls           += st->table_fulls;
1857                 }
1858 
1859                 if (nla_put(skb, NDTA_STATS, sizeof(ndst), &ndst))
1860                         goto nla_put_failure;
1861         }
1862 
1863         BUG_ON(tbl->parms.dev);
1864         if (neightbl_fill_parms(skb, &tbl->parms) < 0)
1865                 goto nla_put_failure;
1866 
1867         read_unlock_bh(&tbl->lock);
1868         nlmsg_end(skb, nlh);
1869         return 0;
1870 
1871 nla_put_failure:
1872         read_unlock_bh(&tbl->lock);
1873         nlmsg_cancel(skb, nlh);
1874         return -EMSGSIZE;
1875 }
1876 
1877 static int neightbl_fill_param_info(struct sk_buff *skb,
1878                                     struct neigh_table *tbl,
1879                                     struct neigh_parms *parms,
1880                                     u32 pid, u32 seq, int type,
1881                                     unsigned int flags)
1882 {
1883         struct ndtmsg *ndtmsg;
1884         struct nlmsghdr *nlh;
1885 
1886         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndtmsg), flags);
1887         if (nlh == NULL)
1888                 return -EMSGSIZE;
1889 
1890         ndtmsg = nlmsg_data(nlh);
1891 
1892         read_lock_bh(&tbl->lock);
1893         ndtmsg->ndtm_family = tbl->family;
1894         ndtmsg->ndtm_pad1   = 0;
1895         ndtmsg->ndtm_pad2   = 0;
1896 
1897         if (nla_put_string(skb, NDTA_NAME, tbl->id) < 0 ||
1898             neightbl_fill_parms(skb, parms) < 0)
1899                 goto errout;
1900 
1901         read_unlock_bh(&tbl->lock);
1902         nlmsg_end(skb, nlh);
1903         return 0;
1904 errout:
1905         read_unlock_bh(&tbl->lock);
1906         nlmsg_cancel(skb, nlh);
1907         return -EMSGSIZE;
1908 }
1909 
1910 static const struct nla_policy nl_neightbl_policy[NDTA_MAX+1] = {
1911         [NDTA_NAME]             = { .type = NLA_STRING },
1912         [NDTA_THRESH1]          = { .type = NLA_U32 },
1913         [NDTA_THRESH2]          = { .type = NLA_U32 },
1914         [NDTA_THRESH3]          = { .type = NLA_U32 },
1915         [NDTA_GC_INTERVAL]      = { .type = NLA_U64 },
1916         [NDTA_PARMS]            = { .type = NLA_NESTED },
1917 };
1918 
1919 static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {
1920         [NDTPA_IFINDEX]                 = { .type = NLA_U32 },
1921         [NDTPA_QUEUE_LEN]               = { .type = NLA_U32 },
1922         [NDTPA_PROXY_QLEN]              = { .type = NLA_U32 },
1923         [NDTPA_APP_PROBES]              = { .type = NLA_U32 },
1924         [NDTPA_UCAST_PROBES]            = { .type = NLA_U32 },
1925         [NDTPA_MCAST_PROBES]            = { .type = NLA_U32 },
1926         [NDTPA_MCAST_REPROBES]          = { .type = NLA_U32 },
1927         [NDTPA_BASE_REACHABLE_TIME]     = { .type = NLA_U64 },
1928         [NDTPA_GC_STALETIME]            = { .type = NLA_U64 },
1929         [NDTPA_DELAY_PROBE_TIME]        = { .type = NLA_U64 },
1930         [NDTPA_RETRANS_TIME]            = { .type = NLA_U64 },
1931         [NDTPA_ANYCAST_DELAY]           = { .type = NLA_U64 },
1932         [NDTPA_PROXY_DELAY]             = { .type = NLA_U64 },
1933         [NDTPA_LOCKTIME]                = { .type = NLA_U64 },
1934 };
1935 
1936 static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh)
1937 {
1938         struct net *net = sock_net(skb->sk);
1939         struct neigh_table *tbl;
1940         struct ndtmsg *ndtmsg;
1941         struct nlattr *tb[NDTA_MAX+1];
1942         bool found = false;
1943         int err, tidx;
1944 
1945         err = nlmsg_parse(nlh, sizeof(*ndtmsg), tb, NDTA_MAX,
1946                           nl_neightbl_policy);
1947         if (err < 0)
1948                 goto errout;
1949 
1950         if (tb[NDTA_NAME] == NULL) {
1951                 err = -EINVAL;
1952                 goto errout;
1953         }
1954 
1955         ndtmsg = nlmsg_data(nlh);
1956 
1957         for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
1958                 tbl = neigh_tables[tidx];
1959                 if (!tbl)
1960                         continue;
1961                 if (ndtmsg->ndtm_family && tbl->family != ndtmsg->ndtm_family)
1962                         continue;
1963                 if (nla_strcmp(tb[NDTA_NAME], tbl->id) == 0) {
1964                         found = true;
1965                         break;
1966                 }
1967         }
1968 
1969         if (!found)
1970                 return -ENOENT;
1971 
1972         /*
1973          * We acquire tbl->lock to be nice to the periodic timers and
1974          * make sure they always see a consistent set of values.
1975          */
1976         write_lock_bh(&tbl->lock);
1977 
1978         if (tb[NDTA_PARMS]) {
1979                 struct nlattr *tbp[NDTPA_MAX+1];
1980                 struct neigh_parms *p;
1981                 int i, ifindex = 0;
1982 
1983                 err = nla_parse_nested(tbp, NDTPA_MAX, tb[NDTA_PARMS],
1984                                        nl_ntbl_parm_policy);
1985                 if (err < 0)
1986                         goto errout_tbl_lock;
1987 
1988                 if (tbp[NDTPA_IFINDEX])
1989                         ifindex = nla_get_u32(tbp[NDTPA_IFINDEX]);
1990 
1991                 p = lookup_neigh_parms(tbl, net, ifindex);
1992                 if (p == NULL) {
1993                         err = -ENOENT;
1994                         goto errout_tbl_lock;
1995                 }
1996 
1997                 for (i = 1; i <= NDTPA_MAX; i++) {
1998                         if (tbp[i] == NULL)
1999                                 continue;
2000 
2001                         switch (i) {
2002                         case NDTPA_QUEUE_LEN:
2003                                 NEIGH_VAR_SET(p, QUEUE_LEN_BYTES,
2004                                               nla_get_u32(tbp[i]) *
2005                                               SKB_TRUESIZE(ETH_FRAME_LEN));
2006                                 break;
2007                         case NDTPA_QUEUE_LENBYTES:
2008                                 NEIGH_VAR_SET(p, QUEUE_LEN_BYTES,
2009                                               nla_get_u32(tbp[i]));
2010                                 break;
2011                         case NDTPA_PROXY_QLEN:
2012                                 NEIGH_VAR_SET(p, PROXY_QLEN,
2013                                               nla_get_u32(tbp[i]));
2014                                 break;
2015                         case NDTPA_APP_PROBES:
2016                                 NEIGH_VAR_SET(p, APP_PROBES,
2017                                               nla_get_u32(tbp[i]));
2018                                 break;
2019                         case NDTPA_UCAST_PROBES:
2020                                 NEIGH_VAR_SET(p, UCAST_PROBES,
2021                                               nla_get_u32(tbp[i]));
2022                                 break;
2023                         case NDTPA_MCAST_PROBES:
2024                                 NEIGH_VAR_SET(p, MCAST_PROBES,
2025                                               nla_get_u32(tbp[i]));
2026                                 break;
2027                         case NDTPA_MCAST_REPROBES:
2028                                 NEIGH_VAR_SET(p, MCAST_REPROBES,
2029                                               nla_get_u32(tbp[i]));
2030                                 break;
2031                         case NDTPA_BASE_REACHABLE_TIME:
2032                                 NEIGH_VAR_SET(p, BASE_REACHABLE_TIME,
2033                                               nla_get_msecs(tbp[i]));
2034                                 /* update reachable_time as well, otherwise, the change will
2035                                  * only be effective after the next time neigh_periodic_work
2036                                  * decides to recompute it (can be multiple minutes)
2037                                  */
2038                                 p->reachable_time =
2039                                         neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
2040                                 break;
2041                         case NDTPA_GC_STALETIME:
2042                                 NEIGH_VAR_SET(p, GC_STALETIME,
2043                                               nla_get_msecs(tbp[i]));
2044                                 break;
2045                         case NDTPA_DELAY_PROBE_TIME:
2046                                 NEIGH_VAR_SET(p, DELAY_PROBE_TIME,
2047                                               nla_get_msecs(tbp[i]));
2048                                 break;
2049                         case NDTPA_RETRANS_TIME:
2050                                 NEIGH_VAR_SET(p, RETRANS_TIME,
2051                                               nla_get_msecs(tbp[i]));
2052                                 break;
2053                         case NDTPA_ANYCAST_DELAY:
2054                                 NEIGH_VAR_SET(p, ANYCAST_DELAY,
2055                                               nla_get_msecs(tbp[i]));
2056                                 break;
2057                         case NDTPA_PROXY_DELAY:
2058                                 NEIGH_VAR_SET(p, PROXY_DELAY,
2059                                               nla_get_msecs(tbp[i]));
2060                                 break;
2061                         case NDTPA_LOCKTIME:
2062                                 NEIGH_VAR_SET(p, LOCKTIME,
2063                                               nla_get_msecs(tbp[i]));
2064                                 break;
2065                         }
2066                 }
2067         }
2068 
2069         err = -ENOENT;
2070         if ((tb[NDTA_THRESH1] || tb[NDTA_THRESH2] ||
2071              tb[NDTA_THRESH3] || tb[NDTA_GC_INTERVAL]) &&
2072             !net_eq(net, &init_net))
2073                 goto errout_tbl_lock;
2074 
2075         if (tb[NDTA_THRESH1])
2076                 tbl->gc_thresh1 = nla_get_u32(tb[NDTA_THRESH1]);
2077 
2078         if (tb[NDTA_THRESH2])
2079                 tbl->gc_thresh2 = nla_get_u32(tb[NDTA_THRESH2]);
2080 
2081         if (tb[NDTA_THRESH3])
2082                 tbl->gc_thresh3 = nla_get_u32(tb[NDTA_THRESH3]);
2083 
2084         if (tb[NDTA_GC_INTERVAL])
2085                 tbl->gc_interval = nla_get_msecs(tb[NDTA_GC_INTERVAL]);
2086 
2087         err = 0;
2088 
2089 errout_tbl_lock:
2090         write_unlock_bh(&tbl->lock);
2091 errout:
2092         return err;
2093 }
2094 
2095 static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
2096 {
2097         struct net *net = sock_net(skb->sk);
2098         int family, tidx, nidx = 0;
2099         int tbl_skip = cb->args[0];
2100         int neigh_skip = cb->args[1];
2101         struct neigh_table *tbl;
2102 
2103         family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
2104 
2105         for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
2106                 struct neigh_parms *p;
2107 
2108                 tbl = neigh_tables[tidx];
2109                 if (!tbl)
2110                         continue;
2111 
2112                 if (tidx < tbl_skip || (family && tbl->family != family))
2113                         continue;
2114 
2115                 if (neightbl_fill_info(skb, tbl, NETLINK_CB(cb->skb).portid,
2116                                        cb->nlh->nlmsg_seq, RTM_NEWNEIGHTBL,
2117                                        NLM_F_MULTI) < 0)
2118                         break;
2119 
2120                 nidx = 0;
2121                 p = list_next_entry(&tbl->parms, list);
2122                 list_for_each_entry_from(p, &tbl->parms_list, list) {
2123                         if (!net_eq(neigh_parms_net(p), net))
2124                                 continue;
2125 
2126                         if (nidx < neigh_skip)
2127                                 goto next;
2128 
2129                         if (neightbl_fill_param_info(skb, tbl, p,
2130                                                      NETLINK_CB(cb->skb).portid,
2131                                                      cb->nlh->nlmsg_seq,
2132                                                      RTM_NEWNEIGHTBL,
2133                                                      NLM_F_MULTI) < 0)
2134                                 goto out;
2135                 next:
2136                         nidx++;
2137                 }
2138 
2139                 neigh_skip = 0;
2140         }
2141 out:
2142         cb->args[0] = tidx;
2143         cb->args[1] = nidx;
2144 
2145         return skb->len;
2146 }
2147 
2148 static int neigh_fill_info(struct sk_buff *skb, struct neighbour *neigh,
2149                            u32 pid, u32 seq, int type, unsigned int flags)
2150 {
2151         unsigned long now = jiffies;
2152         struct nda_cacheinfo ci;
2153         struct nlmsghdr *nlh;
2154         struct ndmsg *ndm;
2155 
2156         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
2157         if (nlh == NULL)
2158                 return -EMSGSIZE;
2159 
2160         ndm = nlmsg_data(nlh);
2161         ndm->ndm_family  = neigh->ops->family;
2162         ndm->ndm_pad1    = 0;
2163         ndm->ndm_pad2    = 0;
2164         ndm->ndm_flags   = neigh->flags;
2165         ndm->ndm_type    = neigh->type;
2166         ndm->ndm_ifindex = neigh->dev->ifindex;
2167 
2168         if (nla_put(skb, NDA_DST, neigh->tbl->key_len, neigh->primary_key))
2169                 goto nla_put_failure;
2170 
2171         read_lock_bh(&neigh->lock);
2172         ndm->ndm_state   = neigh->nud_state;
2173         if (neigh->nud_state & NUD_VALID) {
2174                 char haddr[MAX_ADDR_LEN];
2175 
2176                 neigh_ha_snapshot(haddr, neigh, neigh->dev);
2177                 if (nla_put(skb, NDA_LLADDR, neigh->dev->addr_len, haddr) < 0) {
2178                         read_unlock_bh(&neigh->lock);
2179                         goto nla_put_failure;
2180                 }
2181         }
2182 
2183         ci.ndm_used      = jiffies_to_clock_t(now - neigh->used);
2184         ci.ndm_confirmed = jiffies_to_clock_t(now - neigh->confirmed);
2185         ci.ndm_updated   = jiffies_to_clock_t(now - neigh->updated);
2186         ci.ndm_refcnt    = atomic_read(&neigh->refcnt) - 1;
2187         read_unlock_bh(&neigh->lock);
2188 
2189         if (nla_put_u32(skb, NDA_PROBES, atomic_read(&neigh->probes)) ||
2190             nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
2191                 goto nla_put_failure;
2192 
2193         nlmsg_end(skb, nlh);
2194         return 0;
2195 
2196 nla_put_failure:
2197         nlmsg_cancel(skb, nlh);
2198         return -EMSGSIZE;
2199 }
2200 
2201 static int pneigh_fill_info(struct sk_buff *skb, struct pneigh_entry *pn,
2202                             u32 pid, u32 seq, int type, unsigned int flags,
2203                             struct neigh_table *tbl)
2204 {
2205         struct nlmsghdr *nlh;
2206         struct ndmsg *ndm;
2207 
2208         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
2209         if (nlh == NULL)
2210                 return -EMSGSIZE;
2211 
2212         ndm = nlmsg_data(nlh);
2213         ndm->ndm_family  = tbl->family;
2214         ndm->ndm_pad1    = 0;
2215         ndm->ndm_pad2    = 0;
2216         ndm->ndm_flags   = pn->flags | NTF_PROXY;
2217         ndm->ndm_type    = RTN_UNICAST;
2218         ndm->ndm_ifindex = pn->dev ? pn->dev->ifindex : 0;
2219         ndm->ndm_state   = NUD_NONE;
2220 
2221         if (nla_put(skb, NDA_DST, tbl->key_len, pn->key))
2222                 goto nla_put_failure;
2223 
2224         nlmsg_end(skb, nlh);
2225         return 0;
2226 
2227 nla_put_failure:
2228         nlmsg_cancel(skb, nlh);
2229         return -EMSGSIZE;
2230 }
2231 
2232 static void neigh_update_notify(struct neighbour *neigh)
2233 {
2234         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, neigh);
2235         __neigh_notify(neigh, RTM_NEWNEIGH, 0);
2236 }
2237 
2238 static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
2239                             struct netlink_callback *cb)
2240 {
2241         struct net *net = sock_net(skb->sk);
2242         struct neighbour *n;
2243         int rc, h, s_h = cb->args[1];
2244         int idx, s_idx = idx = cb->args[2];
2245         struct neigh_hash_table *nht;
2246 
2247         rcu_read_lock_bh();
2248         nht = rcu_dereference_bh(tbl->nht);
2249 
2250         for (h = s_h; h < (1 << nht->hash_shift); h++) {
2251                 if (h > s_h)
2252                         s_idx = 0;
2253                 for (n = rcu_dereference_bh(nht->hash_buckets[h]), idx = 0;
2254                      n != NULL;
2255                      n = rcu_dereference_bh(n->next)) {
2256                         if (!net_eq(dev_net(n->dev), net))
2257                                 continue;
2258                         if (idx < s_idx)
2259                                 goto next;
2260                         if (neigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
2261                                             cb->nlh->nlmsg_seq,
2262                                             RTM_NEWNEIGH,
2263                                             NLM_F_MULTI) < 0) {
2264                                 rc = -1;
2265                                 goto out;
2266                         }
2267 next:
2268                         idx++;
2269                 }
2270         }
2271         rc = skb->len;
2272 out:
2273         rcu_read_unlock_bh();
2274         cb->args[1] = h;
2275         cb->args[2] = idx;
2276         return rc;
2277 }
2278 
2279 static int pneigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
2280                              struct netlink_callback *cb)
2281 {
2282         struct pneigh_entry *n;
2283         struct net *net = sock_net(skb->sk);
2284         int rc, h, s_h = cb->args[3];
2285         int idx, s_idx = idx = cb->args[4];
2286 
2287         read_lock_bh(&tbl->lock);
2288 
2289         for (h = s_h; h <= PNEIGH_HASHMASK; h++) {
2290                 if (h > s_h)
2291                         s_idx = 0;
2292                 for (n = tbl->phash_buckets[h], idx = 0; n; n = n->next) {
2293                         if (pneigh_net(n) != net)
2294                                 continue;
2295                         if (idx < s_idx)
2296                                 goto next;
2297                         if (pneigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
2298                                             cb->nlh->nlmsg_seq,
2299                                             RTM_NEWNEIGH,
2300                                             NLM_F_MULTI, tbl) < 0) {
2301                                 read_unlock_bh(&tbl->lock);
2302                                 rc = -1;
2303                                 goto out;
2304                         }
2305                 next:
2306                         idx++;
2307                 }
2308         }
2309 
2310         read_unlock_bh(&tbl->lock);
2311         rc = skb->len;
2312 out:
2313         cb->args[3] = h;
2314         cb->args[4] = idx;
2315         return rc;
2316 
2317 }
2318 
2319 static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
2320 {
2321         struct neigh_table *tbl;
2322         int t, family, s_t;
2323         int proxy = 0;
2324         int err;
2325 
2326         family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
2327 
2328         /* check for full ndmsg structure presence, family member is
2329          * the same for both structures
2330          */
2331         if (nlmsg_len(cb->nlh) >= sizeof(struct ndmsg) &&
2332             ((struct ndmsg *) nlmsg_data(cb->nlh))->ndm_flags == NTF_PROXY)
2333                 proxy = 1;
2334 
2335         s_t = cb->args[0];
2336 
2337         for (t = 0; t < NEIGH_NR_TABLES; t++) {
2338                 tbl = neigh_tables[t];
2339 
2340                 if (!tbl)
2341                         continue;
2342                 if (t < s_t || (family && tbl->family != family))
2343                         continue;
2344                 if (t > s_t)
2345                         memset(&cb->args[1], 0, sizeof(cb->args) -
2346                                                 sizeof(cb->args[0]));
2347                 if (proxy)
2348                         err = pneigh_dump_table(tbl, skb, cb);
2349                 else
2350                         err = neigh_dump_table(tbl, skb, cb);
2351                 if (err < 0)
2352                         break;
2353         }
2354 
2355         cb->args[0] = t;
2356         return skb->len;
2357 }
2358 
2359 void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie)
2360 {
2361         int chain;
2362         struct neigh_hash_table *nht;
2363 
2364         rcu_read_lock_bh();
2365         nht = rcu_dereference_bh(tbl->nht);
2366 
2367         read_lock(&tbl->lock); /* avoid resizes */
2368         for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
2369                 struct neighbour *n;
2370 
2371                 for (n = rcu_dereference_bh(nht->hash_buckets[chain]);
2372                      n != NULL;
2373                      n = rcu_dereference_bh(n->next))
2374                         cb(n, cookie);
2375         }
2376         read_unlock(&tbl->lock);
2377         rcu_read_unlock_bh();
2378 }
2379 EXPORT_SYMBOL(neigh_for_each);
2380 
2381 /* The tbl->lock must be held as a writer and BH disabled. */
2382 void __neigh_for_each_release(struct neigh_table *tbl,
2383                               int (*cb)(struct neighbour *))
2384 {
2385         int chain;
2386         struct neigh_hash_table *nht;
2387 
2388         nht = rcu_dereference_protected(tbl->nht,
2389                                         lockdep_is_held(&tbl->lock));
2390         for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
2391                 struct neighbour *n;
2392                 struct neighbour __rcu **np;
2393 
2394                 np = &nht->hash_buckets[chain];
2395                 while ((n = rcu_dereference_protected(*np,
2396                                         lockdep_is_held(&tbl->lock))) != NULL) {
2397                         int release;
2398 
2399                         write_lock(&n->lock);
2400                         release = cb(n);
2401                         if (release) {
2402                                 rcu_assign_pointer(*np,
2403                                         rcu_dereference_protected(n->next,
2404                                                 lockdep_is_held(&tbl->lock)));
2405                                 n->dead = 1;
2406                         } else
2407                                 np = &n->next;
2408                         write_unlock(&n->lock);
2409                         if (release)
2410                                 neigh_cleanup_and_release(n);
2411                 }
2412         }
2413 }
2414 EXPORT_SYMBOL(__neigh_for_each_release);
2415 
2416 int neigh_xmit(int index, struct net_device *dev,
2417                const void *addr, struct sk_buff *skb)
2418 {
2419         int err = -EAFNOSUPPORT;
2420         if (likely(index < NEIGH_NR_TABLES)) {
2421                 struct neigh_table *tbl;
2422                 struct neighbour *neigh;
2423 
2424                 tbl = neigh_tables[index];
2425                 if (!tbl)
2426                         goto out;
2427                 neigh = __neigh_lookup_noref(tbl, addr, dev);
2428                 if (!neigh)
2429                         neigh = __neigh_create(tbl, addr, dev, false);
2430                 err = PTR_ERR(neigh);
2431                 if (IS_ERR(neigh))
2432                         goto out_kfree_skb;
2433                 err = neigh->output(neigh, skb);
2434         }
2435         else if (index == NEIGH_LINK_TABLE) {
2436                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
2437                                       addr, NULL, skb->len);
2438                 if (err < 0)
2439                         goto out_kfree_skb;
2440                 err = dev_queue_xmit(skb);
2441         }
2442 out:
2443         return err;
2444 out_kfree_skb:
2445         kfree_skb(skb);
2446         goto out;
2447 }
2448 EXPORT_SYMBOL(neigh_xmit);
2449 
2450 #ifdef CONFIG_PROC_FS
2451 
2452 static struct neighbour *neigh_get_first(struct seq_file *seq)
2453 {
2454         struct neigh_seq_state *state = seq->private;
2455         struct net *net = seq_file_net(seq);
2456         struct neigh_hash_table *nht = state->nht;
2457         struct neighbour *n = NULL;
2458         int bucket = state->bucket;
2459 
2460         state->flags &= ~NEIGH_SEQ_IS_PNEIGH;
2461         for (bucket = 0; bucket < (1 << nht->hash_shift); bucket++) {
2462                 n = rcu_dereference_bh(nht->hash_buckets[bucket]);
2463 
2464                 while (n) {
2465                         if (!net_eq(dev_net(n->dev), net))
2466                                 goto next;
2467                         if (state->neigh_sub_iter) {
2468                                 loff_t fakep = 0;
2469                                 void *v;
2470 
2471                                 v = state->neigh_sub_iter(state, n, &fakep);
2472                                 if (!v)
2473                                         goto next;
2474                         }
2475                         if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
2476                                 break;
2477                         if (n->nud_state & ~NUD_NOARP)
2478                                 break;
2479 next:
2480                         n = rcu_dereference_bh(n->next);
2481                 }
2482 
2483                 if (n)
2484                         break;
2485         }
2486         state->bucket = bucket;
2487 
2488         return n;
2489 }
2490 
2491 static struct neighbour *neigh_get_next(struct seq_file *seq,
2492                                         struct neighbour *n,
2493                                         loff_t *pos)
2494 {
2495         struct neigh_seq_state *state = seq->private;
2496         struct net *net = seq_file_net(seq);
2497         struct neigh_hash_table *nht = state->nht;
2498 
2499         if (state->neigh_sub_iter) {
2500                 void *v = state->neigh_sub_iter(state, n, pos);
2501                 if (v)
2502                         return n;
2503         }
2504         n = rcu_dereference_bh(n->next);
2505 
2506         while (1) {
2507                 while (n) {
2508                         if (!net_eq(dev_net(n->dev), net))
2509                                 goto next;
2510                         if (state->neigh_sub_iter) {
2511                                 void *v = state->neigh_sub_iter(state, n, pos);
2512                                 if (v)
2513                                         return n;
2514                                 goto next;
2515                         }
2516                         if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
2517                                 break;
2518 
2519                         if (n->nud_state & ~NUD_NOARP)
2520                                 break;
2521 next:
2522                         n = rcu_dereference_bh(n->next);
2523                 }
2524 
2525                 if (n)
2526                         break;
2527 
2528                 if (++state->bucket >= (1 << nht->hash_shift))
2529                         break;
2530 
2531                 n = rcu_dereference_bh(nht->hash_buckets[state->bucket]);
2532         }
2533 
2534         if (n && pos)
2535                 --(*pos);
2536         return n;
2537 }
2538 
2539 static struct neighbour *neigh_get_idx(struct seq_file *seq, loff_t *pos)
2540 {
2541         struct neighbour *n = neigh_get_first(seq);
2542 
2543         if (n) {
2544                 --(*pos);
2545                 while (*pos) {
2546                         n = neigh_get_next(seq, n, pos);
2547                         if (!n)
2548                                 break;
2549                 }
2550         }
2551         return *pos ? NULL : n;
2552 }
2553 
2554 static struct pneigh_entry *pneigh_get_first(struct seq_file *seq)
2555 {
2556         struct neigh_seq_state *state = seq->private;
2557         struct net *net = seq_file_net(seq);
2558         struct neigh_table *tbl = state->tbl;
2559         struct pneigh_entry *pn = NULL;
2560         int bucket = state->bucket;
2561 
2562         state->flags |= NEIGH_SEQ_IS_PNEIGH;
2563         for (bucket = 0; bucket <= PNEIGH_HASHMASK; bucket++) {
2564                 pn = tbl->phash_buckets[bucket];
2565                 while (pn && !net_eq(pneigh_net(pn), net))
2566                         pn = pn->next;
2567                 if (pn)
2568                         break;
2569         }
2570         state->bucket = bucket;
2571 
2572         return pn;
2573 }
2574 
2575 static struct pneigh_entry *pneigh_get_next(struct seq_file *seq,
2576                                             struct pneigh_entry *pn,
2577                                             loff_t *pos)
2578 {
2579         struct neigh_seq_state *state = seq->private;
2580         struct net *net = seq_file_net(seq);
2581         struct neigh_table *tbl = state->tbl;
2582 
2583         do {
2584                 pn = pn->next;
2585         } while (pn && !net_eq(pneigh_net(pn), net));
2586 
2587         while (!pn) {
2588                 if (++state->bucket > PNEIGH_HASHMASK)
2589                         break;
2590                 pn = tbl->phash_buckets[state->bucket];
2591                 while (pn && !net_eq(pneigh_net(pn), net))
2592                         pn = pn->next;
2593                 if (pn)
2594                         break;
2595         }
2596 
2597         if (pn && pos)
2598                 --(*pos);
2599 
2600         return pn;
2601 }
2602 
2603 static struct pneigh_entry *pneigh_get_idx(struct seq_file *seq, loff_t *pos)
2604 {
2605         struct pneigh_entry *pn = pneigh_get_first(seq);
2606 
2607         if (pn) {
2608                 --(*pos);
2609                 while (*pos) {
2610                         pn = pneigh_get_next(seq, pn, pos);
2611                         if (!pn)
2612                                 break;
2613                 }
2614         }
2615         return *pos ? NULL : pn;
2616 }
2617 
2618 static void *neigh_get_idx_any(struct seq_file *seq, loff_t *pos)
2619 {
2620         struct neigh_seq_state *state = seq->private;
2621         void *rc;
2622         loff_t idxpos = *pos;
2623 
2624         rc = neigh_get_idx(seq, &idxpos);
2625         if (!rc && !(state->flags & NEIGH_SEQ_NEIGH_ONLY))
2626                 rc = pneigh_get_idx(seq, &idxpos);
2627 
2628         return rc;
2629 }
2630 
2631 void *neigh_seq_start(struct seq_file *seq, loff_t *pos, struct neigh_table *tbl, unsigned int neigh_seq_flags)
2632         __acquires(rcu_bh)
2633 {
2634         struct neigh_seq_state *state = seq->private;
2635 
2636         state->tbl = tbl;
2637         state->bucket = 0;
2638         state->flags = (neigh_seq_flags & ~NEIGH_SEQ_IS_PNEIGH);
2639 
2640         rcu_read_lock_bh();
2641         state->nht = rcu_dereference_bh(tbl->nht);
2642 
2643         return *pos ? neigh_get_idx_any(seq, pos) : SEQ_START_TOKEN;
2644 }
2645 EXPORT_SYMBOL(neigh_seq_start);
2646 
2647 void *neigh_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2648 {
2649         struct neigh_seq_state *state;
2650         void *rc;
2651 
2652         if (v == SEQ_START_TOKEN) {
2653                 rc = neigh_get_first(seq);
2654                 goto out;
2655         }
2656 
2657         state = seq->private;
2658         if (!(state->flags & NEIGH_SEQ_IS_PNEIGH)) {
2659                 rc = neigh_get_next(seq, v, NULL);
2660                 if (rc)
2661                         goto out;
2662                 if (!(state->flags & NEIGH_SEQ_NEIGH_ONLY))
2663                         rc = pneigh_get_first(seq);
2664         } else {
2665                 BUG_ON(state->flags & NEIGH_SEQ_NEIGH_ONLY);
2666                 rc = pneigh_get_next(seq, v, NULL);
2667         }
2668 out:
2669         ++(*pos);
2670         return rc;
2671 }
2672 EXPORT_SYMBOL(neigh_seq_next);
2673 
2674 void neigh_seq_stop(struct seq_file *seq, void *v)
2675         __releases(rcu_bh)
2676 {
2677         rcu_read_unlock_bh();
2678 }
2679 EXPORT_SYMBOL(neigh_seq_stop);
2680 
2681 /* statistics via seq_file */
2682 
2683 static void *neigh_stat_seq_start(struct seq_file *seq, loff_t *pos)
2684 {
2685         struct neigh_table *tbl = seq->private;
2686         int cpu;
2687 
2688         if (*pos == 0)
2689                 return SEQ_START_TOKEN;
2690 
2691         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
2692                 if (!cpu_possible(cpu))
2693                         continue;
2694                 *pos = cpu+1;
2695                 return per_cpu_ptr(tbl->stats, cpu);
2696         }
2697         return NULL;
2698 }
2699 
2700 static void *neigh_stat_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2701 {
2702         struct neigh_table *tbl = seq->private;
2703         int cpu;
2704 
2705         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
2706                 if (!cpu_possible(cpu))
2707                         continue;
2708                 *pos = cpu+1;
2709                 return per_cpu_ptr(tbl->stats, cpu);
2710         }
2711         return NULL;
2712 }
2713 
2714 static void neigh_stat_seq_stop(struct seq_file *seq, void *v)
2715 {
2716 
2717 }
2718 
2719 static int neigh_stat_seq_show(struct seq_file *seq, void *v)
2720 {
2721         struct neigh_table *tbl = seq->private;
2722         struct neigh_statistics *st = v;
2723 
2724         if (v == SEQ_START_TOKEN) {
2725                 seq_printf(seq, "entries  allocs destroys hash_grows  lookups hits  res_failed  rcv_probes_mcast rcv_probes_ucast  periodic_gc_runs forced_gc_runs unresolved_discards table_fulls\n");
2726                 return 0;
2727         }
2728 
2729         seq_printf(seq, "%08x  %08lx %08lx %08lx  %08lx %08lx  %08lx  "
2730                         "%08lx %08lx  %08lx %08lx %08lx %08lx\n",
2731                    atomic_read(&tbl->entries),
2732 
2733                    st->allocs,
2734                    st->destroys,
2735                    st->hash_grows,
2736 
2737                    st->lookups,
2738                    st->hits,
2739 
2740                    st->res_failed,
2741 
2742                    st->rcv_probes_mcast,
2743                    st->rcv_probes_ucast,
2744 
2745                    st->periodic_gc_runs,
2746                    st->forced_gc_runs,
2747                    st->unres_discards,
2748                    st->table_fulls
2749                    );
2750 
2751         return 0;
2752 }
2753 
2754 static const struct seq_operations neigh_stat_seq_ops = {
2755         .start  = neigh_stat_seq_start,
2756         .next   = neigh_stat_seq_next,
2757         .stop   = neigh_stat_seq_stop,
2758         .show   = neigh_stat_seq_show,
2759 };
2760 
2761 static int neigh_stat_seq_open(struct inode *inode, struct file *file)
2762 {
2763         int ret = seq_open(file, &neigh_stat_seq_ops);
2764 
2765         if (!ret) {
2766                 struct seq_file *sf = file->private_data;
2767                 sf->private = PDE_DATA(inode);
2768         }
2769         return ret;
2770 };
2771 
2772 static const struct file_operations neigh_stat_seq_fops = {
2773         .owner   = THIS_MODULE,
2774         .open    = neigh_stat_seq_open,
2775         .read    = seq_read,
2776         .llseek  = seq_lseek,
2777         .release = seq_release,
2778 };
2779 
2780 #endif /* CONFIG_PROC_FS */
2781 
2782 static inline size_t neigh_nlmsg_size(void)
2783 {
2784         return NLMSG_ALIGN(sizeof(struct ndmsg))
2785                + nla_total_size(MAX_ADDR_LEN) /* NDA_DST */
2786                + nla_total_size(MAX_ADDR_LEN) /* NDA_LLADDR */
2787                + nla_total_size(sizeof(struct nda_cacheinfo))
2788                + nla_total_size(4); /* NDA_PROBES */
2789 }
2790 
2791 static void __neigh_notify(struct neighbour *n, int type, int flags)
2792 {
2793         struct net *net = dev_net(n->dev);
2794         struct sk_buff *skb;
2795         int err = -ENOBUFS;
2796 
2797         skb = nlmsg_new(neigh_nlmsg_size(), GFP_ATOMIC);
2798         if (skb == NULL)
2799                 goto errout;
2800 
2801         err = neigh_fill_info(skb, n, 0, 0, type, flags);
2802         if (err < 0) {
2803                 /* -EMSGSIZE implies BUG in neigh_nlmsg_size() */
2804                 WARN_ON(err == -EMSGSIZE);
2805                 kfree_skb(skb);
2806                 goto errout;
2807         }
2808         rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
2809         return;
2810 errout:
2811         if (err < 0)
2812                 rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
2813 }
2814 
2815 void neigh_app_ns(struct neighbour *n)
2816 {
2817         __neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
2818 }
2819 EXPORT_SYMBOL(neigh_app_ns);
2820 
2821 #ifdef CONFIG_SYSCTL
2822 static int zero;
2823 static int int_max = INT_MAX;
2824 static int unres_qlen_max = INT_MAX / SKB_TRUESIZE(ETH_FRAME_LEN);
2825 
2826 static int proc_unres_qlen(struct ctl_table *ctl, int write,
2827                            void __user *buffer, size_t *lenp, loff_t *ppos)
2828 {
2829         int size, ret;
2830         struct ctl_table tmp = *ctl;
2831 
2832         tmp.extra1 = &zero;
2833         tmp.extra2 = &unres_qlen_max;
2834         tmp.data = &size;
2835 
2836         size = *(int *)ctl->data / SKB_TRUESIZE(ETH_FRAME_LEN);
2837         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
2838 
2839         if (write && !ret)
2840                 *(int *)ctl->data = size * SKB_TRUESIZE(ETH_FRAME_LEN);
2841         return ret;
2842 }
2843 
2844 static struct neigh_parms *neigh_get_dev_parms_rcu(struct net_device *dev,
2845                                                    int family)
2846 {
2847         switch (family) {
2848         case AF_INET:
2849                 return __in_dev_arp_parms_get_rcu(dev);
2850         case AF_INET6:
2851                 return __in6_dev_nd_parms_get_rcu(dev);
2852         }
2853         return NULL;
2854 }
2855 
2856 static void neigh_copy_dflt_parms(struct net *net, struct neigh_parms *p,
2857                                   int index)
2858 {
2859         struct net_device *dev;
2860         int family = neigh_parms_family(p);
2861 
2862         rcu_read_lock();
2863         for_each_netdev_rcu(net, dev) {
2864                 struct neigh_parms *dst_p =
2865                                 neigh_get_dev_parms_rcu(dev, family);
2866 
2867                 if (dst_p && !test_bit(index, dst_p->data_state))
2868                         dst_p->data[index] = p->data[index];
2869         }
2870         rcu_read_unlock();
2871 }
2872 
2873 static void neigh_proc_update(struct ctl_table *ctl, int write)
2874 {
2875         struct net_device *dev = ctl->extra1;
2876         struct neigh_parms *p = ctl->extra2;
2877         struct net *net = neigh_parms_net(p);
2878         int index = (int *) ctl->data - p->data;
2879 
2880         if (!write)
2881                 return;
2882 
2883         set_bit(index, p->data_state);
2884         if (!dev) /* NULL dev means this is default value */
2885                 neigh_copy_dflt_parms(net, p, index);
2886 }
2887 
2888 static int neigh_proc_dointvec_zero_intmax(struct ctl_table *ctl, int write,
2889                                            void __user *buffer,
2890                                            size_t *lenp, loff_t *ppos)
2891 {
2892         struct ctl_table tmp = *ctl;
2893         int ret;
2894 
2895         tmp.extra1 = &zero;
2896         tmp.extra2 = &int_max;
2897 
2898         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
2899         neigh_proc_update(ctl, write);
2900         return ret;
2901 }
2902 
2903 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
2904                         void __user *buffer, size_t *lenp, loff_t *ppos)
2905 {
2906         int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
2907 
2908         neigh_proc_update(ctl, write);
2909         return ret;
2910 }
2911 EXPORT_SYMBOL(neigh_proc_dointvec);
2912 
2913 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
2914                                 void __user *buffer,
2915                                 size_t *lenp, loff_t *ppos)
2916 {
2917         int ret = proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
2918 
2919         neigh_proc_update(ctl, write);
2920         return ret;
2921 }
2922 EXPORT_SYMBOL(neigh_proc_dointvec_jiffies);
2923 
2924 static int neigh_proc_dointvec_userhz_jiffies(struct ctl_table *ctl, int write,
2925                                               void __user *buffer,
2926                                               size_t *lenp, loff_t *ppos)
2927 {
2928         int ret = proc_dointvec_userhz_jiffies(ctl, write, buffer, lenp, ppos);
2929 
2930         neigh_proc_update(ctl, write);
2931         return ret;
2932 }
2933 
2934 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
2935                                    void __user *buffer,
2936                                    size_t *lenp, loff_t *ppos)
2937 {
2938         int ret = proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
2939 
2940         neigh_proc_update(ctl, write);
2941         return ret;
2942 }
2943 EXPORT_SYMBOL(neigh_proc_dointvec_ms_jiffies);
2944 
2945 static int neigh_proc_dointvec_unres_qlen(struct ctl_table *ctl, int write,
2946                                           void __user *buffer,
2947                                           size_t *lenp, loff_t *ppos)
2948 {
2949         int ret = proc_unres_qlen(ctl, write, buffer, lenp, ppos);
2950 
2951         neigh_proc_update(ctl, write);
2952         return ret;
2953 }
2954 
2955 static int neigh_proc_base_reachable_time(struct ctl_table *ctl, int write,
2956                                           void __user *buffer,
2957                                           size_t *lenp, loff_t *ppos)
2958 {
2959         struct neigh_parms *p = ctl->extra2;
2960         int ret;
2961 
2962         if (strcmp(ctl->procname, "base_reachable_time") == 0)
2963                 ret = neigh_proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
2964         else if (strcmp(ctl->procname, "base_reachable_time_ms") == 0)
2965                 ret = neigh_proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
2966         else
2967                 ret = -1;
2968 
2969         if (write && ret == 0) {
2970                 /* update reachable_time as well, otherwise, the change will
2971                  * only be effective after the next time neigh_periodic_work
2972                  * decides to recompute it
2973                  */
2974                 p->reachable_time =
2975                         neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
2976         }
2977         return ret;
2978 }
2979 
2980 #define NEIGH_PARMS_DATA_OFFSET(index)  \
2981         (&((struct neigh_parms *) 0)->data[index])
2982 
2983 #define NEIGH_SYSCTL_ENTRY(attr, data_attr, name, mval, proc) \
2984         [NEIGH_VAR_ ## attr] = { \
2985                 .procname       = name, \
2986                 .data           = NEIGH_PARMS_DATA_OFFSET(NEIGH_VAR_ ## data_attr), \
2987                 .maxlen         = sizeof(int), \
2988                 .mode           = mval, \
2989                 .proc_handler   = proc, \
2990         }
2991 
2992 #define NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(attr, name) \
2993         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_zero_intmax)
2994 
2995 #define NEIGH_SYSCTL_JIFFIES_ENTRY(attr, name) \
2996         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_jiffies)
2997 
2998 #define NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(attr, name) \
2999         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_userhz_jiffies)
3000 
3001 #define NEIGH_SYSCTL_MS_JIFFIES_ENTRY(attr, name) \
3002         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_ms_jiffies)
3003 
3004 #define NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(attr, data_attr, name) \
3005         NEIGH_SYSCTL_ENTRY(attr, data_attr, name, 0644, neigh_proc_dointvec_ms_jiffies)
3006 
3007 #define NEIGH_SYSCTL_UNRES_QLEN_REUSED_ENTRY(attr, data_attr, name) \
3008         NEIGH_SYSCTL_ENTRY(attr, data_attr, name, 0644, neigh_proc_dointvec_unres_qlen)
3009 
3010 static struct neigh_sysctl_table {
3011         struct ctl_table_header *sysctl_header;
3012         struct ctl_table neigh_vars[NEIGH_VAR_MAX + 1];
3013 } neigh_sysctl_template __read_mostly = {
3014         .neigh_vars = {
3015                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(MCAST_PROBES, "mcast_solicit"),
3016                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(UCAST_PROBES, "ucast_solicit"),
3017                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(APP_PROBES, "app_solicit"),
3018                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(MCAST_REPROBES, "mcast_resolicit"),
3019                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(RETRANS_TIME, "retrans_time"),
3020                 NEIGH_SYSCTL_JIFFIES_ENTRY(BASE_REACHABLE_TIME, "base_reachable_time"),
3021                 NEIGH_SYSCTL_JIFFIES_ENTRY(DELAY_PROBE_TIME, "delay_first_probe_time"),
3022                 NEIGH_SYSCTL_JIFFIES_ENTRY(GC_STALETIME, "gc_stale_time"),
3023                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(QUEUE_LEN_BYTES, "unres_qlen_bytes"),
3024                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(PROXY_QLEN, "proxy_qlen"),
3025                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(ANYCAST_DELAY, "anycast_delay"),
3026                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(PROXY_DELAY, "proxy_delay"),
3027                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(LOCKTIME, "locktime"),
3028                 NEIGH_SYSCTL_UNRES_QLEN_REUSED_ENTRY(QUEUE_LEN, QUEUE_LEN_BYTES, "unres_qlen"),
3029                 NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(RETRANS_TIME_MS, RETRANS_TIME, "retrans_time_ms"),
3030                 NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(BASE_REACHABLE_TIME_MS, BASE_REACHABLE_TIME, "base_reachable_time_ms"),
3031                 [NEIGH_VAR_GC_INTERVAL] = {
3032                         .procname       = "gc_interval",
3033                         .maxlen         = sizeof(int),
3034                         .mode           = 0644,
3035                         .proc_handler   = proc_dointvec_jiffies,
3036                 },
3037                 [NEIGH_VAR_GC_THRESH1] = {
3038                         .procname       = "gc_thresh1",
3039                         .maxlen         = sizeof(int),
3040                         .mode           = 0644,
3041                         .extra1         = &zero,
3042                         .extra2         = &int_max,
3043                         .proc_handler   = proc_dointvec_minmax,
3044                 },
3045                 [NEIGH_VAR_GC_THRESH2] = {
3046                         .procname       = "gc_thresh2",
3047                         .maxlen         = sizeof(int),
3048                         .mode           = 0644,
3049                         .extra1         = &zero,
3050                         .extra2         = &int_max,
3051                         .proc_handler   = proc_dointvec_minmax,
3052                 },
3053                 [NEIGH_VAR_GC_THRESH3] = {
3054                         .procname       = "gc_thresh3",
3055                         .maxlen         = sizeof(int),
3056                         .mode           = 0644,
3057                         .extra1         = &zero,
3058                         .extra2         = &int_max,
3059                         .proc_handler   = proc_dointvec_minmax,
3060                 },
3061                 {},
3062         },
3063 };
3064 
3065 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
3066                           proc_handler *handler)
3067 {
3068         int i;
3069         struct neigh_sysctl_table *t;
3070         const char *dev_name_source;
3071         char neigh_path[ sizeof("net//neigh/") + IFNAMSIZ + IFNAMSIZ ];
3072         char *p_name;
3073 
3074         t = kmemdup(&neigh_sysctl_template, sizeof(*t), GFP_KERNEL);
3075         if (!t)
3076                 goto err;
3077 
3078         for (i = 0; i < NEIGH_VAR_GC_INTERVAL; i++) {
3079                 t->neigh_vars[i].data += (long) p;
3080                 t->neigh_vars[i].extra1 = dev;
3081                 t->neigh_vars[i].extra2 = p;
3082         }
3083 
3084         if (dev) {
3085                 dev_name_source = dev->name;
3086                 /* Terminate the table early */
3087                 memset(&t->neigh_vars[NEIGH_VAR_GC_INTERVAL], 0,
3088                        sizeof(t->neigh_vars[NEIGH_VAR_GC_INTERVAL]));
3089         } else {
3090                 struct neigh_table *tbl = p->tbl;
3091                 dev_name_source = "default";
3092                 t->neigh_vars[NEIGH_VAR_GC_INTERVAL].data = &tbl->gc_interval;
3093                 t->neigh_vars[NEIGH_VAR_GC_THRESH1].data = &tbl->gc_thresh1;
3094                 t->neigh_vars[NEIGH_VAR_GC_THRESH2].data = &tbl->gc_thresh2;
3095                 t->neigh_vars[NEIGH_VAR_GC_THRESH3].data = &tbl->gc_thresh3;
3096         }
3097 
3098         if (handler) {
3099                 /* RetransTime */
3100                 t->neigh_vars[NEIGH_VAR_RETRANS_TIME].proc_handler = handler;
3101                 /* ReachableTime */
3102                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME].proc_handler = handler;
3103                 /* RetransTime (in milliseconds)*/
3104                 t->neigh_vars[NEIGH_VAR_RETRANS_TIME_MS].proc_handler = handler;
3105                 /* ReachableTime (in milliseconds) */
3106                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME_MS].proc_handler = handler;
3107         } else {
3108                 /* Those handlers will update p->reachable_time after
3109                  * base_reachable_time(_ms) is set to ensure the new timer starts being
3110                  * applied after the next neighbour update instead of waiting for
3111                  * neigh_periodic_work to update its value (can be multiple minutes)
3112                  * So any handler that replaces them should do this as well
3113                  */
3114                 /* ReachableTime */
3115                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME].proc_handler =
3116                         neigh_proc_base_reachable_time;
3117                 /* ReachableTime (in milliseconds) */
3118                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME_MS].proc_handler =
3119                         neigh_proc_base_reachable_time;
3120         }
3121 
3122         /* Don't export sysctls to unprivileged users */
3123         if (neigh_parms_net(p)->user_ns != &init_user_ns)
3124                 t->neigh_vars[0].procname = NULL;
3125 
3126         switch (neigh_parms_family(p)) {
3127         case AF_INET:
3128               p_name = "ipv4";
3129               break;
3130         case AF_INET6:
3131               p_name = "ipv6";
3132               break;
3133         default:
3134               BUG();
3135         }
3136 
3137         snprintf(neigh_path, sizeof(neigh_path), "net/%s/neigh/%s",
3138                 p_name, dev_name_source);
3139         t->sysctl_header =
3140                 register_net_sysctl(neigh_parms_net(p), neigh_path, t->neigh_vars);
3141         if (!t->sysctl_header)
3142                 goto free;
3143 
3144         p->sysctl_table = t;
3145         return 0;
3146 
3147 free:
3148         kfree(t);
3149 err:
3150         return -ENOBUFS;
3151 }
3152 EXPORT_SYMBOL(neigh_sysctl_register);
3153 
3154 void neigh_sysctl_unregister(struct neigh_parms *p)
3155 {
3156         if (p->sysctl_table) {
3157                 struct neigh_sysctl_table *t = p->sysctl_table;
3158                 p->sysctl_table = NULL;
3159                 unregister_net_sysctl_table(t->sysctl_header);
3160                 kfree(t);
3161         }
3162 }
3163 EXPORT_SYMBOL(neigh_sysctl_unregister);
3164 
3165 #endif  /* CONFIG_SYSCTL */
3166 
3167 static int __init neigh_init(void)
3168 {
3169         rtnl_register(PF_UNSPEC, RTM_NEWNEIGH, neigh_add, NULL, NULL);
3170         rtnl_register(PF_UNSPEC, RTM_DELNEIGH, neigh_delete, NULL, NULL);
3171         rtnl_register(PF_UNSPEC, RTM_GETNEIGH, NULL, neigh_dump_info, NULL);
3172 
3173         rtnl_register(PF_UNSPEC, RTM_GETNEIGHTBL, NULL, neightbl_dump_info,
3174                       NULL);
3175         rtnl_register(PF_UNSPEC, RTM_SETNEIGHTBL, neightbl_set, NULL, NULL);
3176 
3177         return 0;
3178 }
3179 
3180 subsys_initcall(neigh_init);
3181 
3182 

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