Version:  2.0.40 2.2.26 2.4.37 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7

Linux/net/core/neighbour.c

  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_clone(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                           NDTPA_PAD) ||
1768             nla_put_msecs(skb, NDTPA_BASE_REACHABLE_TIME,
1769                           NEIGH_VAR(parms, BASE_REACHABLE_TIME), NDTPA_PAD) ||
1770             nla_put_msecs(skb, NDTPA_GC_STALETIME,
1771                           NEIGH_VAR(parms, GC_STALETIME), NDTPA_PAD) ||
1772             nla_put_msecs(skb, NDTPA_DELAY_PROBE_TIME,
1773                           NEIGH_VAR(parms, DELAY_PROBE_TIME), NDTPA_PAD) ||
1774             nla_put_msecs(skb, NDTPA_RETRANS_TIME,
1775                           NEIGH_VAR(parms, RETRANS_TIME), NDTPA_PAD) ||
1776             nla_put_msecs(skb, NDTPA_ANYCAST_DELAY,
1777                           NEIGH_VAR(parms, ANYCAST_DELAY), NDTPA_PAD) ||
1778             nla_put_msecs(skb, NDTPA_PROXY_DELAY,
1779                           NEIGH_VAR(parms, PROXY_DELAY), NDTPA_PAD) ||
1780             nla_put_msecs(skb, NDTPA_LOCKTIME,
1781                           NEIGH_VAR(parms, LOCKTIME), NDTPA_PAD))
1782                 goto nla_put_failure;
1783         return nla_nest_end(skb, nest);
1784 
1785 nla_put_failure:
1786         nla_nest_cancel(skb, nest);
1787         return -EMSGSIZE;
1788 }
1789 
1790 static int neightbl_fill_info(struct sk_buff *skb, struct neigh_table *tbl,
1791                               u32 pid, u32 seq, int type, int flags)
1792 {
1793         struct nlmsghdr *nlh;
1794         struct ndtmsg *ndtmsg;
1795 
1796         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndtmsg), flags);
1797         if (nlh == NULL)
1798                 return -EMSGSIZE;
1799 
1800         ndtmsg = nlmsg_data(nlh);
1801 
1802         read_lock_bh(&tbl->lock);
1803         ndtmsg->ndtm_family = tbl->family;
1804         ndtmsg->ndtm_pad1   = 0;
1805         ndtmsg->ndtm_pad2   = 0;
1806 
1807         if (nla_put_string(skb, NDTA_NAME, tbl->id) ||
1808             nla_put_msecs(skb, NDTA_GC_INTERVAL, tbl->gc_interval, NDTA_PAD) ||
1809             nla_put_u32(skb, NDTA_THRESH1, tbl->gc_thresh1) ||
1810             nla_put_u32(skb, NDTA_THRESH2, tbl->gc_thresh2) ||
1811             nla_put_u32(skb, NDTA_THRESH3, tbl->gc_thresh3))
1812                 goto nla_put_failure;
1813         {
1814                 unsigned long now = jiffies;
1815                 unsigned int flush_delta = now - tbl->last_flush;
1816                 unsigned int rand_delta = now - tbl->last_rand;
1817                 struct neigh_hash_table *nht;
1818                 struct ndt_config ndc = {
1819                         .ndtc_key_len           = tbl->key_len,
1820                         .ndtc_entry_size        = tbl->entry_size,
1821                         .ndtc_entries           = atomic_read(&tbl->entries),
1822                         .ndtc_last_flush        = jiffies_to_msecs(flush_delta),
1823                         .ndtc_last_rand         = jiffies_to_msecs(rand_delta),
1824                         .ndtc_proxy_qlen        = tbl->proxy_queue.qlen,
1825                 };
1826 
1827                 rcu_read_lock_bh();
1828                 nht = rcu_dereference_bh(tbl->nht);
1829                 ndc.ndtc_hash_rnd = nht->hash_rnd[0];
1830                 ndc.ndtc_hash_mask = ((1 << nht->hash_shift) - 1);
1831                 rcu_read_unlock_bh();
1832 
1833                 if (nla_put(skb, NDTA_CONFIG, sizeof(ndc), &ndc))
1834                         goto nla_put_failure;
1835         }
1836 
1837         {
1838                 int cpu;
1839                 struct ndt_stats ndst;
1840 
1841                 memset(&ndst, 0, sizeof(ndst));
1842 
1843                 for_each_possible_cpu(cpu) {
1844                         struct neigh_statistics *st;
1845 
1846                         st = per_cpu_ptr(tbl->stats, cpu);
1847                         ndst.ndts_allocs                += st->allocs;
1848                         ndst.ndts_destroys              += st->destroys;
1849                         ndst.ndts_hash_grows            += st->hash_grows;
1850                         ndst.ndts_res_failed            += st->res_failed;
1851                         ndst.ndts_lookups               += st->lookups;
1852                         ndst.ndts_hits                  += st->hits;
1853                         ndst.ndts_rcv_probes_mcast      += st->rcv_probes_mcast;
1854                         ndst.ndts_rcv_probes_ucast      += st->rcv_probes_ucast;
1855                         ndst.ndts_periodic_gc_runs      += st->periodic_gc_runs;
1856                         ndst.ndts_forced_gc_runs        += st->forced_gc_runs;
1857                         ndst.ndts_table_fulls           += st->table_fulls;
1858                 }
1859 
1860                 if (nla_put_64bit(skb, NDTA_STATS, sizeof(ndst), &ndst,
1861                                   NDTA_PAD))
1862                         goto nla_put_failure;
1863         }
1864 
1865         BUG_ON(tbl->parms.dev);
1866         if (neightbl_fill_parms(skb, &tbl->parms) < 0)
1867                 goto nla_put_failure;
1868 
1869         read_unlock_bh(&tbl->lock);
1870         nlmsg_end(skb, nlh);
1871         return 0;
1872 
1873 nla_put_failure:
1874         read_unlock_bh(&tbl->lock);
1875         nlmsg_cancel(skb, nlh);
1876         return -EMSGSIZE;
1877 }
1878 
1879 static int neightbl_fill_param_info(struct sk_buff *skb,
1880                                     struct neigh_table *tbl,
1881                                     struct neigh_parms *parms,
1882                                     u32 pid, u32 seq, int type,
1883                                     unsigned int flags)
1884 {
1885         struct ndtmsg *ndtmsg;
1886         struct nlmsghdr *nlh;
1887 
1888         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndtmsg), flags);
1889         if (nlh == NULL)
1890                 return -EMSGSIZE;
1891 
1892         ndtmsg = nlmsg_data(nlh);
1893 
1894         read_lock_bh(&tbl->lock);
1895         ndtmsg->ndtm_family = tbl->family;
1896         ndtmsg->ndtm_pad1   = 0;
1897         ndtmsg->ndtm_pad2   = 0;
1898 
1899         if (nla_put_string(skb, NDTA_NAME, tbl->id) < 0 ||
1900             neightbl_fill_parms(skb, parms) < 0)
1901                 goto errout;
1902 
1903         read_unlock_bh(&tbl->lock);
1904         nlmsg_end(skb, nlh);
1905         return 0;
1906 errout:
1907         read_unlock_bh(&tbl->lock);
1908         nlmsg_cancel(skb, nlh);
1909         return -EMSGSIZE;
1910 }
1911 
1912 static const struct nla_policy nl_neightbl_policy[NDTA_MAX+1] = {
1913         [NDTA_NAME]             = { .type = NLA_STRING },
1914         [NDTA_THRESH1]          = { .type = NLA_U32 },
1915         [NDTA_THRESH2]          = { .type = NLA_U32 },
1916         [NDTA_THRESH3]          = { .type = NLA_U32 },
1917         [NDTA_GC_INTERVAL]      = { .type = NLA_U64 },
1918         [NDTA_PARMS]            = { .type = NLA_NESTED },
1919 };
1920 
1921 static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {
1922         [NDTPA_IFINDEX]                 = { .type = NLA_U32 },
1923         [NDTPA_QUEUE_LEN]               = { .type = NLA_U32 },
1924         [NDTPA_PROXY_QLEN]              = { .type = NLA_U32 },
1925         [NDTPA_APP_PROBES]              = { .type = NLA_U32 },
1926         [NDTPA_UCAST_PROBES]            = { .type = NLA_U32 },
1927         [NDTPA_MCAST_PROBES]            = { .type = NLA_U32 },
1928         [NDTPA_MCAST_REPROBES]          = { .type = NLA_U32 },
1929         [NDTPA_BASE_REACHABLE_TIME]     = { .type = NLA_U64 },
1930         [NDTPA_GC_STALETIME]            = { .type = NLA_U64 },
1931         [NDTPA_DELAY_PROBE_TIME]        = { .type = NLA_U64 },
1932         [NDTPA_RETRANS_TIME]            = { .type = NLA_U64 },
1933         [NDTPA_ANYCAST_DELAY]           = { .type = NLA_U64 },
1934         [NDTPA_PROXY_DELAY]             = { .type = NLA_U64 },
1935         [NDTPA_LOCKTIME]                = { .type = NLA_U64 },
1936 };
1937 
1938 static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh)
1939 {
1940         struct net *net = sock_net(skb->sk);
1941         struct neigh_table *tbl;
1942         struct ndtmsg *ndtmsg;
1943         struct nlattr *tb[NDTA_MAX+1];
1944         bool found = false;
1945         int err, tidx;
1946 
1947         err = nlmsg_parse(nlh, sizeof(*ndtmsg), tb, NDTA_MAX,
1948                           nl_neightbl_policy);
1949         if (err < 0)
1950                 goto errout;
1951 
1952         if (tb[NDTA_NAME] == NULL) {
1953                 err = -EINVAL;
1954                 goto errout;
1955         }
1956 
1957         ndtmsg = nlmsg_data(nlh);
1958 
1959         for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
1960                 tbl = neigh_tables[tidx];
1961                 if (!tbl)
1962                         continue;
1963                 if (ndtmsg->ndtm_family && tbl->family != ndtmsg->ndtm_family)
1964                         continue;
1965                 if (nla_strcmp(tb[NDTA_NAME], tbl->id) == 0) {
1966                         found = true;
1967                         break;
1968                 }
1969         }
1970 
1971         if (!found)
1972                 return -ENOENT;
1973 
1974         /*
1975          * We acquire tbl->lock to be nice to the periodic timers and
1976          * make sure they always see a consistent set of values.
1977          */
1978         write_lock_bh(&tbl->lock);
1979 
1980         if (tb[NDTA_PARMS]) {
1981                 struct nlattr *tbp[NDTPA_MAX+1];
1982                 struct neigh_parms *p;
1983                 int i, ifindex = 0;
1984 
1985                 err = nla_parse_nested(tbp, NDTPA_MAX, tb[NDTA_PARMS],
1986                                        nl_ntbl_parm_policy);
1987                 if (err < 0)
1988                         goto errout_tbl_lock;
1989 
1990                 if (tbp[NDTPA_IFINDEX])
1991                         ifindex = nla_get_u32(tbp[NDTPA_IFINDEX]);
1992 
1993                 p = lookup_neigh_parms(tbl, net, ifindex);
1994                 if (p == NULL) {
1995                         err = -ENOENT;
1996                         goto errout_tbl_lock;
1997                 }
1998 
1999                 for (i = 1; i <= NDTPA_MAX; i++) {
2000                         if (tbp[i] == NULL)
2001                                 continue;
2002 
2003                         switch (i) {
2004                         case NDTPA_QUEUE_LEN:
2005                                 NEIGH_VAR_SET(p, QUEUE_LEN_BYTES,
2006                                               nla_get_u32(tbp[i]) *
2007                                               SKB_TRUESIZE(ETH_FRAME_LEN));
2008                                 break;
2009                         case NDTPA_QUEUE_LENBYTES:
2010                                 NEIGH_VAR_SET(p, QUEUE_LEN_BYTES,
2011                                               nla_get_u32(tbp[i]));
2012                                 break;
2013                         case NDTPA_PROXY_QLEN:
2014                                 NEIGH_VAR_SET(p, PROXY_QLEN,
2015                                               nla_get_u32(tbp[i]));
2016                                 break;
2017                         case NDTPA_APP_PROBES:
2018                                 NEIGH_VAR_SET(p, APP_PROBES,
2019                                               nla_get_u32(tbp[i]));
2020                                 break;
2021                         case NDTPA_UCAST_PROBES:
2022                                 NEIGH_VAR_SET(p, UCAST_PROBES,
2023                                               nla_get_u32(tbp[i]));
2024                                 break;
2025                         case NDTPA_MCAST_PROBES:
2026                                 NEIGH_VAR_SET(p, MCAST_PROBES,
2027                                               nla_get_u32(tbp[i]));
2028                                 break;
2029                         case NDTPA_MCAST_REPROBES:
2030                                 NEIGH_VAR_SET(p, MCAST_REPROBES,
2031                                               nla_get_u32(tbp[i]));
2032                                 break;
2033                         case NDTPA_BASE_REACHABLE_TIME:
2034                                 NEIGH_VAR_SET(p, BASE_REACHABLE_TIME,
2035                                               nla_get_msecs(tbp[i]));
2036                                 /* update reachable_time as well, otherwise, the change will
2037                                  * only be effective after the next time neigh_periodic_work
2038                                  * decides to recompute it (can be multiple minutes)
2039                                  */
2040                                 p->reachable_time =
2041                                         neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
2042                                 break;
2043                         case NDTPA_GC_STALETIME:
2044                                 NEIGH_VAR_SET(p, GC_STALETIME,
2045                                               nla_get_msecs(tbp[i]));
2046                                 break;
2047                         case NDTPA_DELAY_PROBE_TIME:
2048                                 NEIGH_VAR_SET(p, DELAY_PROBE_TIME,
2049                                               nla_get_msecs(tbp[i]));
2050                                 break;
2051                         case NDTPA_RETRANS_TIME:
2052                                 NEIGH_VAR_SET(p, RETRANS_TIME,
2053                                               nla_get_msecs(tbp[i]));
2054                                 break;
2055                         case NDTPA_ANYCAST_DELAY:
2056                                 NEIGH_VAR_SET(p, ANYCAST_DELAY,
2057                                               nla_get_msecs(tbp[i]));
2058                                 break;
2059                         case NDTPA_PROXY_DELAY:
2060                                 NEIGH_VAR_SET(p, PROXY_DELAY,
2061                                               nla_get_msecs(tbp[i]));
2062                                 break;
2063                         case NDTPA_LOCKTIME:
2064                                 NEIGH_VAR_SET(p, LOCKTIME,
2065                                               nla_get_msecs(tbp[i]));
2066                                 break;
2067                         }
2068                 }
2069         }
2070 
2071         err = -ENOENT;
2072         if ((tb[NDTA_THRESH1] || tb[NDTA_THRESH2] ||
2073              tb[NDTA_THRESH3] || tb[NDTA_GC_INTERVAL]) &&
2074             !net_eq(net, &init_net))
2075                 goto errout_tbl_lock;
2076 
2077         if (tb[NDTA_THRESH1])
2078                 tbl->gc_thresh1 = nla_get_u32(tb[NDTA_THRESH1]);
2079 
2080         if (tb[NDTA_THRESH2])
2081                 tbl->gc_thresh2 = nla_get_u32(tb[NDTA_THRESH2]);
2082 
2083         if (tb[NDTA_THRESH3])
2084                 tbl->gc_thresh3 = nla_get_u32(tb[NDTA_THRESH3]);
2085 
2086         if (tb[NDTA_GC_INTERVAL])
2087                 tbl->gc_interval = nla_get_msecs(tb[NDTA_GC_INTERVAL]);
2088 
2089         err = 0;
2090 
2091 errout_tbl_lock:
2092         write_unlock_bh(&tbl->lock);
2093 errout:
2094         return err;
2095 }
2096 
2097 static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
2098 {
2099         struct net *net = sock_net(skb->sk);
2100         int family, tidx, nidx = 0;
2101         int tbl_skip = cb->args[0];
2102         int neigh_skip = cb->args[1];
2103         struct neigh_table *tbl;
2104 
2105         family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
2106 
2107         for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
2108                 struct neigh_parms *p;
2109 
2110                 tbl = neigh_tables[tidx];
2111                 if (!tbl)
2112                         continue;
2113 
2114                 if (tidx < tbl_skip || (family && tbl->family != family))
2115                         continue;
2116 
2117                 if (neightbl_fill_info(skb, tbl, NETLINK_CB(cb->skb).portid,
2118                                        cb->nlh->nlmsg_seq, RTM_NEWNEIGHTBL,
2119                                        NLM_F_MULTI) < 0)
2120                         break;
2121 
2122                 nidx = 0;
2123                 p = list_next_entry(&tbl->parms, list);
2124                 list_for_each_entry_from(p, &tbl->parms_list, list) {
2125                         if (!net_eq(neigh_parms_net(p), net))
2126                                 continue;
2127 
2128                         if (nidx < neigh_skip)
2129                                 goto next;
2130 
2131                         if (neightbl_fill_param_info(skb, tbl, p,
2132                                                      NETLINK_CB(cb->skb).portid,
2133                                                      cb->nlh->nlmsg_seq,
2134                                                      RTM_NEWNEIGHTBL,
2135                                                      NLM_F_MULTI) < 0)
2136                                 goto out;
2137                 next:
2138                         nidx++;
2139                 }
2140 
2141                 neigh_skip = 0;
2142         }
2143 out:
2144         cb->args[0] = tidx;
2145         cb->args[1] = nidx;
2146 
2147         return skb->len;
2148 }
2149 
2150 static int neigh_fill_info(struct sk_buff *skb, struct neighbour *neigh,
2151                            u32 pid, u32 seq, int type, unsigned int flags)
2152 {
2153         unsigned long now = jiffies;
2154         struct nda_cacheinfo ci;
2155         struct nlmsghdr *nlh;
2156         struct ndmsg *ndm;
2157 
2158         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
2159         if (nlh == NULL)
2160                 return -EMSGSIZE;
2161 
2162         ndm = nlmsg_data(nlh);
2163         ndm->ndm_family  = neigh->ops->family;
2164         ndm->ndm_pad1    = 0;
2165         ndm->ndm_pad2    = 0;
2166         ndm->ndm_flags   = neigh->flags;
2167         ndm->ndm_type    = neigh->type;
2168         ndm->ndm_ifindex = neigh->dev->ifindex;
2169 
2170         if (nla_put(skb, NDA_DST, neigh->tbl->key_len, neigh->primary_key))
2171                 goto nla_put_failure;
2172 
2173         read_lock_bh(&neigh->lock);
2174         ndm->ndm_state   = neigh->nud_state;
2175         if (neigh->nud_state & NUD_VALID) {
2176                 char haddr[MAX_ADDR_LEN];
2177 
2178                 neigh_ha_snapshot(haddr, neigh, neigh->dev);
2179                 if (nla_put(skb, NDA_LLADDR, neigh->dev->addr_len, haddr) < 0) {
2180                         read_unlock_bh(&neigh->lock);
2181                         goto nla_put_failure;
2182                 }
2183         }
2184 
2185         ci.ndm_used      = jiffies_to_clock_t(now - neigh->used);
2186         ci.ndm_confirmed = jiffies_to_clock_t(now - neigh->confirmed);
2187         ci.ndm_updated   = jiffies_to_clock_t(now - neigh->updated);
2188         ci.ndm_refcnt    = atomic_read(&neigh->refcnt) - 1;
2189         read_unlock_bh(&neigh->lock);
2190 
2191         if (nla_put_u32(skb, NDA_PROBES, atomic_read(&neigh->probes)) ||
2192             nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
2193                 goto nla_put_failure;
2194 
2195         nlmsg_end(skb, nlh);
2196         return 0;
2197 
2198 nla_put_failure:
2199         nlmsg_cancel(skb, nlh);
2200         return -EMSGSIZE;
2201 }
2202 
2203 static int pneigh_fill_info(struct sk_buff *skb, struct pneigh_entry *pn,
2204                             u32 pid, u32 seq, int type, unsigned int flags,
2205                             struct neigh_table *tbl)
2206 {
2207         struct nlmsghdr *nlh;
2208         struct ndmsg *ndm;
2209 
2210         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
2211         if (nlh == NULL)
2212                 return -EMSGSIZE;
2213 
2214         ndm = nlmsg_data(nlh);
2215         ndm->ndm_family  = tbl->family;
2216         ndm->ndm_pad1    = 0;
2217         ndm->ndm_pad2    = 0;
2218         ndm->ndm_flags   = pn->flags | NTF_PROXY;
2219         ndm->ndm_type    = RTN_UNICAST;
2220         ndm->ndm_ifindex = pn->dev ? pn->dev->ifindex : 0;
2221         ndm->ndm_state   = NUD_NONE;
2222 
2223         if (nla_put(skb, NDA_DST, tbl->key_len, pn->key))
2224                 goto nla_put_failure;
2225 
2226         nlmsg_end(skb, nlh);
2227         return 0;
2228 
2229 nla_put_failure:
2230         nlmsg_cancel(skb, nlh);
2231         return -EMSGSIZE;
2232 }
2233 
2234 static void neigh_update_notify(struct neighbour *neigh)
2235 {
2236         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, neigh);
2237         __neigh_notify(neigh, RTM_NEWNEIGH, 0);
2238 }
2239 
2240 static bool neigh_master_filtered(struct net_device *dev, int master_idx)
2241 {
2242         struct net_device *master;
2243 
2244         if (!master_idx)
2245                 return false;
2246 
2247         master = netdev_master_upper_dev_get(dev);
2248         if (!master || master->ifindex != master_idx)
2249                 return true;
2250 
2251         return false;
2252 }
2253 
2254 static bool neigh_ifindex_filtered(struct net_device *dev, int filter_idx)
2255 {
2256         if (filter_idx && dev->ifindex != filter_idx)
2257                 return true;
2258 
2259         return false;
2260 }
2261 
2262 static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
2263                             struct netlink_callback *cb)
2264 {
2265         struct net *net = sock_net(skb->sk);
2266         const struct nlmsghdr *nlh = cb->nlh;
2267         struct nlattr *tb[NDA_MAX + 1];
2268         struct neighbour *n;
2269         int rc, h, s_h = cb->args[1];
2270         int idx, s_idx = idx = cb->args[2];
2271         struct neigh_hash_table *nht;
2272         int filter_master_idx = 0, filter_idx = 0;
2273         unsigned int flags = NLM_F_MULTI;
2274         int err;
2275 
2276         err = nlmsg_parse(nlh, sizeof(struct ndmsg), tb, NDA_MAX, NULL);
2277         if (!err) {
2278                 if (tb[NDA_IFINDEX])
2279                         filter_idx = nla_get_u32(tb[NDA_IFINDEX]);
2280 
2281                 if (tb[NDA_MASTER])
2282                         filter_master_idx = nla_get_u32(tb[NDA_MASTER]);
2283 
2284                 if (filter_idx || filter_master_idx)
2285                         flags |= NLM_F_DUMP_FILTERED;
2286         }
2287 
2288         rcu_read_lock_bh();
2289         nht = rcu_dereference_bh(tbl->nht);
2290 
2291         for (h = s_h; h < (1 << nht->hash_shift); h++) {
2292                 if (h > s_h)
2293                         s_idx = 0;
2294                 for (n = rcu_dereference_bh(nht->hash_buckets[h]), idx = 0;
2295                      n != NULL;
2296                      n = rcu_dereference_bh(n->next)) {
2297                         if (!net_eq(dev_net(n->dev), net))
2298                                 continue;
2299                         if (neigh_ifindex_filtered(n->dev, filter_idx))
2300                                 continue;
2301                         if (neigh_master_filtered(n->dev, filter_master_idx))
2302                                 continue;
2303                         if (idx < s_idx)
2304                                 goto next;
2305                         if (neigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
2306                                             cb->nlh->nlmsg_seq,
2307                                             RTM_NEWNEIGH,
2308                                             flags) < 0) {
2309                                 rc = -1;
2310                                 goto out;
2311                         }
2312 next:
2313                         idx++;
2314                 }
2315         }
2316         rc = skb->len;
2317 out:
2318         rcu_read_unlock_bh();
2319         cb->args[1] = h;
2320         cb->args[2] = idx;
2321         return rc;
2322 }
2323 
2324 static int pneigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
2325                              struct netlink_callback *cb)
2326 {
2327         struct pneigh_entry *n;
2328         struct net *net = sock_net(skb->sk);
2329         int rc, h, s_h = cb->args[3];
2330         int idx, s_idx = idx = cb->args[4];
2331 
2332         read_lock_bh(&tbl->lock);
2333 
2334         for (h = s_h; h <= PNEIGH_HASHMASK; h++) {
2335                 if (h > s_h)
2336                         s_idx = 0;
2337                 for (n = tbl->phash_buckets[h], idx = 0; n; n = n->next) {
2338                         if (pneigh_net(n) != net)
2339                                 continue;
2340                         if (idx < s_idx)
2341                                 goto next;
2342                         if (pneigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
2343                                             cb->nlh->nlmsg_seq,
2344                                             RTM_NEWNEIGH,
2345                                             NLM_F_MULTI, tbl) < 0) {
2346                                 read_unlock_bh(&tbl->lock);
2347                                 rc = -1;
2348                                 goto out;
2349                         }
2350                 next:
2351                         idx++;
2352                 }
2353         }
2354 
2355         read_unlock_bh(&tbl->lock);
2356         rc = skb->len;
2357 out:
2358         cb->args[3] = h;
2359         cb->args[4] = idx;
2360         return rc;
2361 
2362 }
2363 
2364 static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
2365 {
2366         struct neigh_table *tbl;
2367         int t, family, s_t;
2368         int proxy = 0;
2369         int err;
2370 
2371         family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
2372 
2373         /* check for full ndmsg structure presence, family member is
2374          * the same for both structures
2375          */
2376         if (nlmsg_len(cb->nlh) >= sizeof(struct ndmsg) &&
2377             ((struct ndmsg *) nlmsg_data(cb->nlh))->ndm_flags == NTF_PROXY)
2378                 proxy = 1;
2379 
2380         s_t = cb->args[0];
2381 
2382         for (t = 0; t < NEIGH_NR_TABLES; t++) {
2383                 tbl = neigh_tables[t];
2384 
2385                 if (!tbl)
2386                         continue;
2387                 if (t < s_t || (family && tbl->family != family))
2388                         continue;
2389                 if (t > s_t)
2390                         memset(&cb->args[1], 0, sizeof(cb->args) -
2391                                                 sizeof(cb->args[0]));
2392                 if (proxy)
2393                         err = pneigh_dump_table(tbl, skb, cb);
2394                 else
2395                         err = neigh_dump_table(tbl, skb, cb);
2396                 if (err < 0)
2397                         break;
2398         }
2399 
2400         cb->args[0] = t;
2401         return skb->len;
2402 }
2403 
2404 void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie)
2405 {
2406         int chain;
2407         struct neigh_hash_table *nht;
2408 
2409         rcu_read_lock_bh();
2410         nht = rcu_dereference_bh(tbl->nht);
2411 
2412         read_lock(&tbl->lock); /* avoid resizes */
2413         for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
2414                 struct neighbour *n;
2415 
2416                 for (n = rcu_dereference_bh(nht->hash_buckets[chain]);
2417                      n != NULL;
2418                      n = rcu_dereference_bh(n->next))
2419                         cb(n, cookie);
2420         }
2421         read_unlock(&tbl->lock);
2422         rcu_read_unlock_bh();
2423 }
2424 EXPORT_SYMBOL(neigh_for_each);
2425 
2426 /* The tbl->lock must be held as a writer and BH disabled. */
2427 void __neigh_for_each_release(struct neigh_table *tbl,
2428                               int (*cb)(struct neighbour *))
2429 {
2430         int chain;
2431         struct neigh_hash_table *nht;
2432 
2433         nht = rcu_dereference_protected(tbl->nht,
2434                                         lockdep_is_held(&tbl->lock));
2435         for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
2436                 struct neighbour *n;
2437                 struct neighbour __rcu **np;
2438 
2439                 np = &nht->hash_buckets[chain];
2440                 while ((n = rcu_dereference_protected(*np,
2441                                         lockdep_is_held(&tbl->lock))) != NULL) {
2442                         int release;
2443 
2444                         write_lock(&n->lock);
2445                         release = cb(n);
2446                         if (release) {
2447                                 rcu_assign_pointer(*np,
2448                                         rcu_dereference_protected(n->next,
2449                                                 lockdep_is_held(&tbl->lock)));
2450                                 n->dead = 1;
2451                         } else
2452                                 np = &n->next;
2453                         write_unlock(&n->lock);
2454                         if (release)
2455                                 neigh_cleanup_and_release(n);
2456                 }
2457         }
2458 }
2459 EXPORT_SYMBOL(__neigh_for_each_release);
2460 
2461 int neigh_xmit(int index, struct net_device *dev,
2462                const void *addr, struct sk_buff *skb)
2463 {
2464         int err = -EAFNOSUPPORT;
2465         if (likely(index < NEIGH_NR_TABLES)) {
2466                 struct neigh_table *tbl;
2467                 struct neighbour *neigh;
2468 
2469                 tbl = neigh_tables[index];
2470                 if (!tbl)
2471                         goto out;
2472                 rcu_read_lock_bh();
2473                 neigh = __neigh_lookup_noref(tbl, addr, dev);
2474                 if (!neigh)
2475                         neigh = __neigh_create(tbl, addr, dev, false);
2476                 err = PTR_ERR(neigh);
2477                 if (IS_ERR(neigh)) {
2478                         rcu_read_unlock_bh();
2479                         goto out_kfree_skb;
2480                 }
2481                 err = neigh->output(neigh, skb);
2482                 rcu_read_unlock_bh();
2483         }
2484         else if (index == NEIGH_LINK_TABLE) {
2485                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
2486                                       addr, NULL, skb->len);
2487                 if (err < 0)
2488                         goto out_kfree_skb;
2489                 err = dev_queue_xmit(skb);
2490         }
2491 out:
2492         return err;
2493 out_kfree_skb:
2494         kfree_skb(skb);
2495         goto out;
2496 }
2497 EXPORT_SYMBOL(neigh_xmit);
2498 
2499 #ifdef CONFIG_PROC_FS
2500 
2501 static struct neighbour *neigh_get_first(struct seq_file *seq)
2502 {
2503         struct neigh_seq_state *state = seq->private;
2504         struct net *net = seq_file_net(seq);
2505         struct neigh_hash_table *nht = state->nht;
2506         struct neighbour *n = NULL;
2507         int bucket = state->bucket;
2508 
2509         state->flags &= ~NEIGH_SEQ_IS_PNEIGH;
2510         for (bucket = 0; bucket < (1 << nht->hash_shift); bucket++) {
2511                 n = rcu_dereference_bh(nht->hash_buckets[bucket]);
2512 
2513                 while (n) {
2514                         if (!net_eq(dev_net(n->dev), net))
2515                                 goto next;
2516                         if (state->neigh_sub_iter) {
2517                                 loff_t fakep = 0;
2518                                 void *v;
2519 
2520                                 v = state->neigh_sub_iter(state, n, &fakep);
2521                                 if (!v)
2522                                         goto next;
2523                         }
2524                         if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
2525                                 break;
2526                         if (n->nud_state & ~NUD_NOARP)
2527                                 break;
2528 next:
2529                         n = rcu_dereference_bh(n->next);
2530                 }
2531 
2532                 if (n)
2533                         break;
2534         }
2535         state->bucket = bucket;
2536 
2537         return n;
2538 }
2539 
2540 static struct neighbour *neigh_get_next(struct seq_file *seq,
2541                                         struct neighbour *n,
2542                                         loff_t *pos)
2543 {
2544         struct neigh_seq_state *state = seq->private;
2545         struct net *net = seq_file_net(seq);
2546         struct neigh_hash_table *nht = state->nht;
2547 
2548         if (state->neigh_sub_iter) {
2549                 void *v = state->neigh_sub_iter(state, n, pos);
2550                 if (v)
2551                         return n;
2552         }
2553         n = rcu_dereference_bh(n->next);
2554 
2555         while (1) {
2556                 while (n) {
2557                         if (!net_eq(dev_net(n->dev), net))
2558                                 goto next;
2559                         if (state->neigh_sub_iter) {
2560                                 void *v = state->neigh_sub_iter(state, n, pos);
2561                                 if (v)
2562                                         return n;
2563                                 goto next;
2564                         }
2565                         if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
2566                                 break;
2567 
2568                         if (n->nud_state & ~NUD_NOARP)
2569                                 break;
2570 next:
2571                         n = rcu_dereference_bh(n->next);
2572                 }
2573 
2574                 if (n)
2575                         break;
2576 
2577                 if (++state->bucket >= (1 << nht->hash_shift))
2578                         break;
2579 
2580                 n = rcu_dereference_bh(nht->hash_buckets[state->bucket]);
2581         }
2582 
2583         if (n && pos)
2584                 --(*pos);
2585         return n;
2586 }
2587 
2588 static struct neighbour *neigh_get_idx(struct seq_file *seq, loff_t *pos)
2589 {
2590         struct neighbour *n = neigh_get_first(seq);
2591 
2592         if (n) {
2593                 --(*pos);
2594                 while (*pos) {
2595                         n = neigh_get_next(seq, n, pos);
2596                         if (!n)
2597                                 break;
2598                 }
2599         }
2600         return *pos ? NULL : n;
2601 }
2602 
2603 static struct pneigh_entry *pneigh_get_first(struct seq_file *seq)
2604 {
2605         struct neigh_seq_state *state = seq->private;
2606         struct net *net = seq_file_net(seq);
2607         struct neigh_table *tbl = state->tbl;
2608         struct pneigh_entry *pn = NULL;
2609         int bucket = state->bucket;
2610 
2611         state->flags |= NEIGH_SEQ_IS_PNEIGH;
2612         for (bucket = 0; bucket <= PNEIGH_HASHMASK; bucket++) {
2613                 pn = tbl->phash_buckets[bucket];
2614                 while (pn && !net_eq(pneigh_net(pn), net))
2615                         pn = pn->next;
2616                 if (pn)
2617                         break;
2618         }
2619         state->bucket = bucket;
2620 
2621         return pn;
2622 }
2623 
2624 static struct pneigh_entry *pneigh_get_next(struct seq_file *seq,
2625                                             struct pneigh_entry *pn,
2626                                             loff_t *pos)
2627 {
2628         struct neigh_seq_state *state = seq->private;
2629         struct net *net = seq_file_net(seq);
2630         struct neigh_table *tbl = state->tbl;
2631 
2632         do {
2633                 pn = pn->next;
2634         } while (pn && !net_eq(pneigh_net(pn), net));
2635 
2636         while (!pn) {
2637                 if (++state->bucket > PNEIGH_HASHMASK)
2638                         break;
2639                 pn = tbl->phash_buckets[state->bucket];
2640                 while (pn && !net_eq(pneigh_net(pn), net))
2641                         pn = pn->next;
2642                 if (pn)
2643                         break;
2644         }
2645 
2646         if (pn && pos)
2647                 --(*pos);
2648 
2649         return pn;
2650 }
2651 
2652 static struct pneigh_entry *pneigh_get_idx(struct seq_file *seq, loff_t *pos)
2653 {
2654         struct pneigh_entry *pn = pneigh_get_first(seq);
2655 
2656         if (pn) {
2657                 --(*pos);
2658                 while (*pos) {
2659                         pn = pneigh_get_next(seq, pn, pos);
2660                         if (!pn)
2661                                 break;
2662                 }
2663         }
2664         return *pos ? NULL : pn;
2665 }
2666 
2667 static void *neigh_get_idx_any(struct seq_file *seq, loff_t *pos)
2668 {
2669         struct neigh_seq_state *state = seq->private;
2670         void *rc;
2671         loff_t idxpos = *pos;
2672 
2673         rc = neigh_get_idx(seq, &idxpos);
2674         if (!rc && !(state->flags & NEIGH_SEQ_NEIGH_ONLY))
2675                 rc = pneigh_get_idx(seq, &idxpos);
2676 
2677         return rc;
2678 }
2679 
2680 void *neigh_seq_start(struct seq_file *seq, loff_t *pos, struct neigh_table *tbl, unsigned int neigh_seq_flags)
2681         __acquires(rcu_bh)
2682 {
2683         struct neigh_seq_state *state = seq->private;
2684 
2685         state->tbl = tbl;
2686         state->bucket = 0;
2687         state->flags = (neigh_seq_flags & ~NEIGH_SEQ_IS_PNEIGH);
2688 
2689         rcu_read_lock_bh();
2690         state->nht = rcu_dereference_bh(tbl->nht);
2691 
2692         return *pos ? neigh_get_idx_any(seq, pos) : SEQ_START_TOKEN;
2693 }
2694 EXPORT_SYMBOL(neigh_seq_start);
2695 
2696 void *neigh_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2697 {
2698         struct neigh_seq_state *state;
2699         void *rc;
2700 
2701         if (v == SEQ_START_TOKEN) {
2702                 rc = neigh_get_first(seq);
2703                 goto out;
2704         }
2705 
2706         state = seq->private;
2707         if (!(state->flags & NEIGH_SEQ_IS_PNEIGH)) {
2708                 rc = neigh_get_next(seq, v, NULL);
2709                 if (rc)
2710                         goto out;
2711                 if (!(state->flags & NEIGH_SEQ_NEIGH_ONLY))
2712                         rc = pneigh_get_first(seq);
2713         } else {
2714                 BUG_ON(state->flags & NEIGH_SEQ_NEIGH_ONLY);
2715                 rc = pneigh_get_next(seq, v, NULL);
2716         }
2717 out:
2718         ++(*pos);
2719         return rc;
2720 }
2721 EXPORT_SYMBOL(neigh_seq_next);
2722 
2723 void neigh_seq_stop(struct seq_file *seq, void *v)
2724         __releases(rcu_bh)
2725 {
2726         rcu_read_unlock_bh();
2727 }
2728 EXPORT_SYMBOL(neigh_seq_stop);
2729 
2730 /* statistics via seq_file */
2731 
2732 static void *neigh_stat_seq_start(struct seq_file *seq, loff_t *pos)
2733 {
2734         struct neigh_table *tbl = seq->private;
2735         int cpu;
2736 
2737         if (*pos == 0)
2738                 return SEQ_START_TOKEN;
2739 
2740         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
2741                 if (!cpu_possible(cpu))
2742                         continue;
2743                 *pos = cpu+1;
2744                 return per_cpu_ptr(tbl->stats, cpu);
2745         }
2746         return NULL;
2747 }
2748 
2749 static void *neigh_stat_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2750 {
2751         struct neigh_table *tbl = seq->private;
2752         int cpu;
2753 
2754         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
2755                 if (!cpu_possible(cpu))
2756                         continue;
2757                 *pos = cpu+1;
2758                 return per_cpu_ptr(tbl->stats, cpu);
2759         }
2760         return NULL;
2761 }
2762 
2763 static void neigh_stat_seq_stop(struct seq_file *seq, void *v)
2764 {
2765 
2766 }
2767 
2768 static int neigh_stat_seq_show(struct seq_file *seq, void *v)
2769 {
2770         struct neigh_table *tbl = seq->private;
2771         struct neigh_statistics *st = v;
2772 
2773         if (v == SEQ_START_TOKEN) {
2774                 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");
2775                 return 0;
2776         }
2777 
2778         seq_printf(seq, "%08x  %08lx %08lx %08lx  %08lx %08lx  %08lx  "
2779                         "%08lx %08lx  %08lx %08lx %08lx %08lx\n",
2780                    atomic_read(&tbl->entries),
2781 
2782                    st->allocs,
2783                    st->destroys,
2784                    st->hash_grows,
2785 
2786                    st->lookups,
2787                    st->hits,
2788 
2789                    st->res_failed,
2790 
2791                    st->rcv_probes_mcast,
2792                    st->rcv_probes_ucast,
2793 
2794                    st->periodic_gc_runs,
2795                    st->forced_gc_runs,
2796                    st->unres_discards,
2797                    st->table_fulls
2798                    );
2799 
2800         return 0;
2801 }
2802 
2803 static const struct seq_operations neigh_stat_seq_ops = {
2804         .start  = neigh_stat_seq_start,
2805         .next   = neigh_stat_seq_next,
2806         .stop   = neigh_stat_seq_stop,
2807         .show   = neigh_stat_seq_show,
2808 };
2809 
2810 static int neigh_stat_seq_open(struct inode *inode, struct file *file)
2811 {
2812         int ret = seq_open(file, &neigh_stat_seq_ops);
2813 
2814         if (!ret) {
2815                 struct seq_file *sf = file->private_data;
2816                 sf->private = PDE_DATA(inode);
2817         }
2818         return ret;
2819 };
2820 
2821 static const struct file_operations neigh_stat_seq_fops = {
2822         .owner   = THIS_MODULE,
2823         .open    = neigh_stat_seq_open,
2824         .read    = seq_read,
2825         .llseek  = seq_lseek,
2826         .release = seq_release,
2827 };
2828 
2829 #endif /* CONFIG_PROC_FS */
2830 
2831 static inline size_t neigh_nlmsg_size(void)
2832 {
2833         return NLMSG_ALIGN(sizeof(struct ndmsg))
2834                + nla_total_size(MAX_ADDR_LEN) /* NDA_DST */
2835                + nla_total_size(MAX_ADDR_LEN) /* NDA_LLADDR */
2836                + nla_total_size(sizeof(struct nda_cacheinfo))
2837                + nla_total_size(4); /* NDA_PROBES */
2838 }
2839 
2840 static void __neigh_notify(struct neighbour *n, int type, int flags)
2841 {
2842         struct net *net = dev_net(n->dev);
2843         struct sk_buff *skb;
2844         int err = -ENOBUFS;
2845 
2846         skb = nlmsg_new(neigh_nlmsg_size(), GFP_ATOMIC);
2847         if (skb == NULL)
2848                 goto errout;
2849 
2850         err = neigh_fill_info(skb, n, 0, 0, type, flags);
2851         if (err < 0) {
2852                 /* -EMSGSIZE implies BUG in neigh_nlmsg_size() */
2853                 WARN_ON(err == -EMSGSIZE);
2854                 kfree_skb(skb);
2855                 goto errout;
2856         }
2857         rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
2858         return;
2859 errout:
2860         if (err < 0)
2861                 rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
2862 }
2863 
2864 void neigh_app_ns(struct neighbour *n)
2865 {
2866         __neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
2867 }
2868 EXPORT_SYMBOL(neigh_app_ns);
2869 
2870 #ifdef CONFIG_SYSCTL
2871 static int zero;
2872 static int int_max = INT_MAX;
2873 static int unres_qlen_max = INT_MAX / SKB_TRUESIZE(ETH_FRAME_LEN);
2874 
2875 static int proc_unres_qlen(struct ctl_table *ctl, int write,
2876                            void __user *buffer, size_t *lenp, loff_t *ppos)
2877 {
2878         int size, ret;
2879         struct ctl_table tmp = *ctl;
2880 
2881         tmp.extra1 = &zero;
2882         tmp.extra2 = &unres_qlen_max;
2883         tmp.data = &size;
2884 
2885         size = *(int *)ctl->data / SKB_TRUESIZE(ETH_FRAME_LEN);
2886         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
2887 
2888         if (write && !ret)
2889                 *(int *)ctl->data = size * SKB_TRUESIZE(ETH_FRAME_LEN);
2890         return ret;
2891 }
2892 
2893 static struct neigh_parms *neigh_get_dev_parms_rcu(struct net_device *dev,
2894                                                    int family)
2895 {
2896         switch (family) {
2897         case AF_INET:
2898                 return __in_dev_arp_parms_get_rcu(dev);
2899         case AF_INET6:
2900                 return __in6_dev_nd_parms_get_rcu(dev);
2901         }
2902         return NULL;
2903 }
2904 
2905 static void neigh_copy_dflt_parms(struct net *net, struct neigh_parms *p,
2906                                   int index)
2907 {
2908         struct net_device *dev;
2909         int family = neigh_parms_family(p);
2910 
2911         rcu_read_lock();
2912         for_each_netdev_rcu(net, dev) {
2913                 struct neigh_parms *dst_p =
2914                                 neigh_get_dev_parms_rcu(dev, family);
2915 
2916                 if (dst_p && !test_bit(index, dst_p->data_state))
2917                         dst_p->data[index] = p->data[index];
2918         }
2919         rcu_read_unlock();
2920 }
2921 
2922 static void neigh_proc_update(struct ctl_table *ctl, int write)
2923 {
2924         struct net_device *dev = ctl->extra1;
2925         struct neigh_parms *p = ctl->extra2;
2926         struct net *net = neigh_parms_net(p);
2927         int index = (int *) ctl->data - p->data;
2928 
2929         if (!write)
2930                 return;
2931 
2932         set_bit(index, p->data_state);
2933         if (!dev) /* NULL dev means this is default value */
2934                 neigh_copy_dflt_parms(net, p, index);
2935 }
2936 
2937 static int neigh_proc_dointvec_zero_intmax(struct ctl_table *ctl, int write,
2938                                            void __user *buffer,
2939                                            size_t *lenp, loff_t *ppos)
2940 {
2941         struct ctl_table tmp = *ctl;
2942         int ret;
2943 
2944         tmp.extra1 = &zero;
2945         tmp.extra2 = &int_max;
2946 
2947         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
2948         neigh_proc_update(ctl, write);
2949         return ret;
2950 }
2951 
2952 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
2953                         void __user *buffer, size_t *lenp, loff_t *ppos)
2954 {
2955         int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
2956 
2957         neigh_proc_update(ctl, write);
2958         return ret;
2959 }
2960 EXPORT_SYMBOL(neigh_proc_dointvec);
2961 
2962 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
2963                                 void __user *buffer,
2964                                 size_t *lenp, loff_t *ppos)
2965 {
2966         int ret = proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
2967 
2968         neigh_proc_update(ctl, write);
2969         return ret;
2970 }
2971 EXPORT_SYMBOL(neigh_proc_dointvec_jiffies);
2972 
2973 static int neigh_proc_dointvec_userhz_jiffies(struct ctl_table *ctl, int write,
2974                                               void __user *buffer,
2975                                               size_t *lenp, loff_t *ppos)
2976 {
2977         int ret = proc_dointvec_userhz_jiffies(ctl, write, buffer, lenp, ppos);
2978 
2979         neigh_proc_update(ctl, write);
2980         return ret;
2981 }
2982 
2983 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
2984                                    void __user *buffer,
2985                                    size_t *lenp, loff_t *ppos)
2986 {
2987         int ret = proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
2988 
2989         neigh_proc_update(ctl, write);
2990         return ret;
2991 }
2992 EXPORT_SYMBOL(neigh_proc_dointvec_ms_jiffies);
2993 
2994 static int neigh_proc_dointvec_unres_qlen(struct ctl_table *ctl, int write,
2995                                           void __user *buffer,
2996                                           size_t *lenp, loff_t *ppos)
2997 {
2998         int ret = proc_unres_qlen(ctl, write, buffer, lenp, ppos);
2999 
3000         neigh_proc_update(ctl, write);
3001         return ret;
3002 }
3003 
3004 static int neigh_proc_base_reachable_time(struct ctl_table *ctl, int write,
3005                                           void __user *buffer,
3006                                           size_t *lenp, loff_t *ppos)
3007 {
3008         struct neigh_parms *p = ctl->extra2;
3009         int ret;
3010 
3011         if (strcmp(ctl->procname, "base_reachable_time") == 0)
3012                 ret = neigh_proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
3013         else if (strcmp(ctl->procname, "base_reachable_time_ms") == 0)
3014                 ret = neigh_proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
3015         else
3016                 ret = -1;
3017 
3018         if (write && ret == 0) {
3019                 /* update reachable_time as well, otherwise, the change will
3020                  * only be effective after the next time neigh_periodic_work
3021                  * decides to recompute it
3022                  */
3023                 p->reachable_time =
3024                         neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
3025         }
3026         return ret;
3027 }
3028 
3029 #define NEIGH_PARMS_DATA_OFFSET(index)  \
3030         (&((struct neigh_parms *) 0)->data[index])
3031 
3032 #define NEIGH_SYSCTL_ENTRY(attr, data_attr, name, mval, proc) \
3033         [NEIGH_VAR_ ## attr] = { \
3034                 .procname       = name, \
3035                 .data           = NEIGH_PARMS_DATA_OFFSET(NEIGH_VAR_ ## data_attr), \
3036                 .maxlen         = sizeof(int), \
3037                 .mode           = mval, \
3038                 .proc_handler   = proc, \
3039         }
3040 
3041 #define NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(attr, name) \
3042         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_zero_intmax)
3043 
3044 #define NEIGH_SYSCTL_JIFFIES_ENTRY(attr, name) \
3045         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_jiffies)
3046 
3047 #define NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(attr, name) \
3048         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_userhz_jiffies)
3049 
3050 #define NEIGH_SYSCTL_MS_JIFFIES_ENTRY(attr, name) \
3051         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_ms_jiffies)
3052 
3053 #define NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(attr, data_attr, name) \
3054         NEIGH_SYSCTL_ENTRY(attr, data_attr, name, 0644, neigh_proc_dointvec_ms_jiffies)
3055 
3056 #define NEIGH_SYSCTL_UNRES_QLEN_REUSED_ENTRY(attr, data_attr, name) \
3057         NEIGH_SYSCTL_ENTRY(attr, data_attr, name, 0644, neigh_proc_dointvec_unres_qlen)
3058 
3059 static struct neigh_sysctl_table {
3060         struct ctl_table_header *sysctl_header;
3061         struct ctl_table neigh_vars[NEIGH_VAR_MAX + 1];
3062 } neigh_sysctl_template __read_mostly = {
3063         .neigh_vars = {
3064                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(MCAST_PROBES, "mcast_solicit"),
3065                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(UCAST_PROBES, "ucast_solicit"),
3066                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(APP_PROBES, "app_solicit"),
3067                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(MCAST_REPROBES, "mcast_resolicit"),
3068                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(RETRANS_TIME, "retrans_time"),
3069                 NEIGH_SYSCTL_JIFFIES_ENTRY(BASE_REACHABLE_TIME, "base_reachable_time"),
3070                 NEIGH_SYSCTL_JIFFIES_ENTRY(DELAY_PROBE_TIME, "delay_first_probe_time"),
3071                 NEIGH_SYSCTL_JIFFIES_ENTRY(GC_STALETIME, "gc_stale_time"),
3072                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(QUEUE_LEN_BYTES, "unres_qlen_bytes"),
3073                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(PROXY_QLEN, "proxy_qlen"),
3074                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(ANYCAST_DELAY, "anycast_delay"),
3075                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(PROXY_DELAY, "proxy_delay"),
3076                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(LOCKTIME, "locktime"),
3077                 NEIGH_SYSCTL_UNRES_QLEN_REUSED_ENTRY(QUEUE_LEN, QUEUE_LEN_BYTES, "unres_qlen"),
3078                 NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(RETRANS_TIME_MS, RETRANS_TIME, "retrans_time_ms"),
3079                 NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(BASE_REACHABLE_TIME_MS, BASE_REACHABLE_TIME, "base_reachable_time_ms"),
3080                 [NEIGH_VAR_GC_INTERVAL] = {
3081                         .procname       = "gc_interval",
3082                         .maxlen         = sizeof(int),
3083                         .mode           = 0644,
3084                         .proc_handler   = proc_dointvec_jiffies,
3085                 },
3086                 [NEIGH_VAR_GC_THRESH1] = {
3087                         .procname       = "gc_thresh1",
3088                         .maxlen         = sizeof(int),
3089                         .mode           = 0644,
3090                         .extra1         = &zero,
3091                         .extra2         = &int_max,
3092                         .proc_handler   = proc_dointvec_minmax,
3093                 },
3094                 [NEIGH_VAR_GC_THRESH2] = {
3095                         .procname       = "gc_thresh2",
3096                         .maxlen         = sizeof(int),
3097                         .mode           = 0644,
3098                         .extra1         = &zero,
3099                         .extra2         = &int_max,
3100                         .proc_handler   = proc_dointvec_minmax,
3101                 },
3102                 [NEIGH_VAR_GC_THRESH3] = {
3103                         .procname       = "gc_thresh3",
3104                         .maxlen         = sizeof(int),
3105                         .mode           = 0644,
3106                         .extra1         = &zero,
3107                         .extra2         = &int_max,
3108                         .proc_handler   = proc_dointvec_minmax,
3109                 },
3110                 {},
3111         },
3112 };
3113 
3114 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
3115                           proc_handler *handler)
3116 {
3117         int i;
3118         struct neigh_sysctl_table *t;
3119         const char *dev_name_source;
3120         char neigh_path[ sizeof("net//neigh/") + IFNAMSIZ + IFNAMSIZ ];
3121         char *p_name;
3122 
3123         t = kmemdup(&neigh_sysctl_template, sizeof(*t), GFP_KERNEL);
3124         if (!t)
3125                 goto err;
3126 
3127         for (i = 0; i < NEIGH_VAR_GC_INTERVAL; i++) {
3128                 t->neigh_vars[i].data += (long) p;
3129                 t->neigh_vars[i].extra1 = dev;
3130                 t->neigh_vars[i].extra2 = p;
3131         }
3132 
3133         if (dev) {
3134                 dev_name_source = dev->name;
3135                 /* Terminate the table early */
3136                 memset(&t->neigh_vars[NEIGH_VAR_GC_INTERVAL], 0,
3137                        sizeof(t->neigh_vars[NEIGH_VAR_GC_INTERVAL]));
3138         } else {
3139                 struct neigh_table *tbl = p->tbl;
3140                 dev_name_source = "default";
3141                 t->neigh_vars[NEIGH_VAR_GC_INTERVAL].data = &tbl->gc_interval;
3142                 t->neigh_vars[NEIGH_VAR_GC_THRESH1].data = &tbl->gc_thresh1;
3143                 t->neigh_vars[NEIGH_VAR_GC_THRESH2].data = &tbl->gc_thresh2;
3144                 t->neigh_vars[NEIGH_VAR_GC_THRESH3].data = &tbl->gc_thresh3;
3145         }
3146 
3147         if (handler) {
3148                 /* RetransTime */
3149                 t->neigh_vars[NEIGH_VAR_RETRANS_TIME].proc_handler = handler;
3150                 /* ReachableTime */
3151                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME].proc_handler = handler;
3152                 /* RetransTime (in milliseconds)*/
3153                 t->neigh_vars[NEIGH_VAR_RETRANS_TIME_MS].proc_handler = handler;
3154                 /* ReachableTime (in milliseconds) */
3155                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME_MS].proc_handler = handler;
3156         } else {
3157                 /* Those handlers will update p->reachable_time after
3158                  * base_reachable_time(_ms) is set to ensure the new timer starts being
3159                  * applied after the next neighbour update instead of waiting for
3160                  * neigh_periodic_work to update its value (can be multiple minutes)
3161                  * So any handler that replaces them should do this as well
3162                  */
3163                 /* ReachableTime */
3164                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME].proc_handler =
3165                         neigh_proc_base_reachable_time;
3166                 /* ReachableTime (in milliseconds) */
3167                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME_MS].proc_handler =
3168                         neigh_proc_base_reachable_time;
3169         }
3170 
3171         /* Don't export sysctls to unprivileged users */
3172         if (neigh_parms_net(p)->user_ns != &init_user_ns)
3173                 t->neigh_vars[0].procname = NULL;
3174 
3175         switch (neigh_parms_family(p)) {
3176         case AF_INET:
3177               p_name = "ipv4";
3178               break;
3179         case AF_INET6:
3180               p_name = "ipv6";
3181               break;
3182         default:
3183               BUG();
3184         }
3185 
3186         snprintf(neigh_path, sizeof(neigh_path), "net/%s/neigh/%s",
3187                 p_name, dev_name_source);
3188         t->sysctl_header =
3189                 register_net_sysctl(neigh_parms_net(p), neigh_path, t->neigh_vars);
3190         if (!t->sysctl_header)
3191                 goto free;
3192 
3193         p->sysctl_table = t;
3194         return 0;
3195 
3196 free:
3197         kfree(t);
3198 err:
3199         return -ENOBUFS;
3200 }
3201 EXPORT_SYMBOL(neigh_sysctl_register);
3202 
3203 void neigh_sysctl_unregister(struct neigh_parms *p)
3204 {
3205         if (p->sysctl_table) {
3206                 struct neigh_sysctl_table *t = p->sysctl_table;
3207                 p->sysctl_table = NULL;
3208                 unregister_net_sysctl_table(t->sysctl_header);
3209                 kfree(t);
3210         }
3211 }
3212 EXPORT_SYMBOL(neigh_sysctl_unregister);
3213 
3214 #endif  /* CONFIG_SYSCTL */
3215 
3216 static int __init neigh_init(void)
3217 {
3218         rtnl_register(PF_UNSPEC, RTM_NEWNEIGH, neigh_add, NULL, NULL);
3219         rtnl_register(PF_UNSPEC, RTM_DELNEIGH, neigh_delete, NULL, NULL);
3220         rtnl_register(PF_UNSPEC, RTM_GETNEIGH, NULL, neigh_dump_info, NULL);
3221 
3222         rtnl_register(PF_UNSPEC, RTM_GETNEIGHTBL, NULL, neightbl_dump_info,
3223                       NULL);
3224         rtnl_register(PF_UNSPEC, RTM_SETNEIGHTBL, neightbl_set, NULL, NULL);
3225 
3226         return 0;
3227 }
3228 
3229 subsys_initcall(neigh_init);
3230 
3231 

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