Version:  2.0.40 2.2.26 2.4.37 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 4.8 4.9

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(dev, 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(dev, 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         NEIGH_UPDATE_F_ADMIN    means that the change is administrative.
1064 
1065         NEIGH_UPDATE_F_OVERRIDE_ISROUTER allows to override existing
1066                                 NTF_ROUTER flag.
1067         NEIGH_UPDATE_F_ISROUTER indicates if the neighbour is known as
1068                                 a router.
1069 
1070    Caller MUST hold reference count on the entry.
1071  */
1072 
1073 int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
1074                  u32 flags)
1075 {
1076         u8 old;
1077         int err;
1078         int notify = 0;
1079         struct net_device *dev;
1080         int update_isrouter = 0;
1081 
1082         write_lock_bh(&neigh->lock);
1083 
1084         dev    = neigh->dev;
1085         old    = neigh->nud_state;
1086         err    = -EPERM;
1087 
1088         if (!(flags & NEIGH_UPDATE_F_ADMIN) &&
1089             (old & (NUD_NOARP | NUD_PERMANENT)))
1090                 goto out;
1091         if (neigh->dead)
1092                 goto out;
1093 
1094         if (!(new & NUD_VALID)) {
1095                 neigh_del_timer(neigh);
1096                 if (old & NUD_CONNECTED)
1097                         neigh_suspect(neigh);
1098                 neigh->nud_state = new;
1099                 err = 0;
1100                 notify = old & NUD_VALID;
1101                 if ((old & (NUD_INCOMPLETE | NUD_PROBE)) &&
1102                     (new & NUD_FAILED)) {
1103                         neigh_invalidate(neigh);
1104                         notify = 1;
1105                 }
1106                 goto out;
1107         }
1108 
1109         /* Compare new lladdr with cached one */
1110         if (!dev->addr_len) {
1111                 /* First case: device needs no address. */
1112                 lladdr = neigh->ha;
1113         } else if (lladdr) {
1114                 /* The second case: if something is already cached
1115                    and a new address is proposed:
1116                    - compare new & old
1117                    - if they are different, check override flag
1118                  */
1119                 if ((old & NUD_VALID) &&
1120                     !memcmp(lladdr, neigh->ha, dev->addr_len))
1121                         lladdr = neigh->ha;
1122         } else {
1123                 /* No address is supplied; if we know something,
1124                    use it, otherwise discard the request.
1125                  */
1126                 err = -EINVAL;
1127                 if (!(old & NUD_VALID))
1128                         goto out;
1129                 lladdr = neigh->ha;
1130         }
1131 
1132         if (new & NUD_CONNECTED)
1133                 neigh->confirmed = jiffies;
1134         neigh->updated = jiffies;
1135 
1136         /* If entry was valid and address is not changed,
1137            do not change entry state, if new one is STALE.
1138          */
1139         err = 0;
1140         update_isrouter = flags & NEIGH_UPDATE_F_OVERRIDE_ISROUTER;
1141         if (old & NUD_VALID) {
1142                 if (lladdr != neigh->ha && !(flags & NEIGH_UPDATE_F_OVERRIDE)) {
1143                         update_isrouter = 0;
1144                         if ((flags & NEIGH_UPDATE_F_WEAK_OVERRIDE) &&
1145                             (old & NUD_CONNECTED)) {
1146                                 lladdr = neigh->ha;
1147                                 new = NUD_STALE;
1148                         } else
1149                                 goto out;
1150                 } else {
1151                         if (lladdr == neigh->ha && new == NUD_STALE &&
1152                             !(flags & NEIGH_UPDATE_F_ADMIN))
1153                                 new = old;
1154                 }
1155         }
1156 
1157         if (new != old) {
1158                 neigh_del_timer(neigh);
1159                 if (new & NUD_PROBE)
1160                         atomic_set(&neigh->probes, 0);
1161                 if (new & NUD_IN_TIMER)
1162                         neigh_add_timer(neigh, (jiffies +
1163                                                 ((new & NUD_REACHABLE) ?
1164                                                  neigh->parms->reachable_time :
1165                                                  0)));
1166                 neigh->nud_state = new;
1167                 notify = 1;
1168         }
1169 
1170         if (lladdr != neigh->ha) {
1171                 write_seqlock(&neigh->ha_lock);
1172                 memcpy(&neigh->ha, lladdr, dev->addr_len);
1173                 write_sequnlock(&neigh->ha_lock);
1174                 neigh_update_hhs(neigh);
1175                 if (!(new & NUD_CONNECTED))
1176                         neigh->confirmed = jiffies -
1177                                       (NEIGH_VAR(neigh->parms, BASE_REACHABLE_TIME) << 1);
1178                 notify = 1;
1179         }
1180         if (new == old)
1181                 goto out;
1182         if (new & NUD_CONNECTED)
1183                 neigh_connect(neigh);
1184         else
1185                 neigh_suspect(neigh);
1186         if (!(old & NUD_VALID)) {
1187                 struct sk_buff *skb;
1188 
1189                 /* Again: avoid dead loop if something went wrong */
1190 
1191                 while (neigh->nud_state & NUD_VALID &&
1192                        (skb = __skb_dequeue(&neigh->arp_queue)) != NULL) {
1193                         struct dst_entry *dst = skb_dst(skb);
1194                         struct neighbour *n2, *n1 = neigh;
1195                         write_unlock_bh(&neigh->lock);
1196 
1197                         rcu_read_lock();
1198 
1199                         /* Why not just use 'neigh' as-is?  The problem is that
1200                          * things such as shaper, eql, and sch_teql can end up
1201                          * using alternative, different, neigh objects to output
1202                          * the packet in the output path.  So what we need to do
1203                          * here is re-lookup the top-level neigh in the path so
1204                          * we can reinject the packet there.
1205                          */
1206                         n2 = NULL;
1207                         if (dst) {
1208                                 n2 = dst_neigh_lookup_skb(dst, skb);
1209                                 if (n2)
1210                                         n1 = n2;
1211                         }
1212                         n1->output(n1, skb);
1213                         if (n2)
1214                                 neigh_release(n2);
1215                         rcu_read_unlock();
1216 
1217                         write_lock_bh(&neigh->lock);
1218                 }
1219                 __skb_queue_purge(&neigh->arp_queue);
1220                 neigh->arp_queue_len_bytes = 0;
1221         }
1222 out:
1223         if (update_isrouter) {
1224                 neigh->flags = (flags & NEIGH_UPDATE_F_ISROUTER) ?
1225                         (neigh->flags | NTF_ROUTER) :
1226                         (neigh->flags & ~NTF_ROUTER);
1227         }
1228         write_unlock_bh(&neigh->lock);
1229 
1230         if (notify)
1231                 neigh_update_notify(neigh);
1232 
1233         return err;
1234 }
1235 EXPORT_SYMBOL(neigh_update);
1236 
1237 /* Update the neigh to listen temporarily for probe responses, even if it is
1238  * in a NUD_FAILED state. The caller has to hold neigh->lock for writing.
1239  */
1240 void __neigh_set_probe_once(struct neighbour *neigh)
1241 {
1242         if (neigh->dead)
1243                 return;
1244         neigh->updated = jiffies;
1245         if (!(neigh->nud_state & NUD_FAILED))
1246                 return;
1247         neigh->nud_state = NUD_INCOMPLETE;
1248         atomic_set(&neigh->probes, neigh_max_probes(neigh));
1249         neigh_add_timer(neigh,
1250                         jiffies + NEIGH_VAR(neigh->parms, RETRANS_TIME));
1251 }
1252 EXPORT_SYMBOL(__neigh_set_probe_once);
1253 
1254 struct neighbour *neigh_event_ns(struct neigh_table *tbl,
1255                                  u8 *lladdr, void *saddr,
1256                                  struct net_device *dev)
1257 {
1258         struct neighbour *neigh = __neigh_lookup(tbl, saddr, dev,
1259                                                  lladdr || !dev->addr_len);
1260         if (neigh)
1261                 neigh_update(neigh, lladdr, NUD_STALE,
1262                              NEIGH_UPDATE_F_OVERRIDE);
1263         return neigh;
1264 }
1265 EXPORT_SYMBOL(neigh_event_ns);
1266 
1267 /* called with read_lock_bh(&n->lock); */
1268 static void neigh_hh_init(struct neighbour *n)
1269 {
1270         struct net_device *dev = n->dev;
1271         __be16 prot = n->tbl->protocol;
1272         struct hh_cache *hh = &n->hh;
1273 
1274         write_lock_bh(&n->lock);
1275 
1276         /* Only one thread can come in here and initialize the
1277          * hh_cache entry.
1278          */
1279         if (!hh->hh_len)
1280                 dev->header_ops->cache(n, hh, prot);
1281 
1282         write_unlock_bh(&n->lock);
1283 }
1284 
1285 /* Slow and careful. */
1286 
1287 int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb)
1288 {
1289         int rc = 0;
1290 
1291         if (!neigh_event_send(neigh, skb)) {
1292                 int err;
1293                 struct net_device *dev = neigh->dev;
1294                 unsigned int seq;
1295 
1296                 if (dev->header_ops->cache && !neigh->hh.hh_len)
1297                         neigh_hh_init(neigh);
1298 
1299                 do {
1300                         __skb_pull(skb, skb_network_offset(skb));
1301                         seq = read_seqbegin(&neigh->ha_lock);
1302                         err = dev_hard_header(skb, dev, ntohs(skb->protocol),
1303                                               neigh->ha, NULL, skb->len);
1304                 } while (read_seqretry(&neigh->ha_lock, seq));
1305 
1306                 if (err >= 0)
1307                         rc = dev_queue_xmit(skb);
1308                 else
1309                         goto out_kfree_skb;
1310         }
1311 out:
1312         return rc;
1313 out_kfree_skb:
1314         rc = -EINVAL;
1315         kfree_skb(skb);
1316         goto out;
1317 }
1318 EXPORT_SYMBOL(neigh_resolve_output);
1319 
1320 /* As fast as possible without hh cache */
1321 
1322 int neigh_connected_output(struct neighbour *neigh, struct sk_buff *skb)
1323 {
1324         struct net_device *dev = neigh->dev;
1325         unsigned int seq;
1326         int err;
1327 
1328         do {
1329                 __skb_pull(skb, skb_network_offset(skb));
1330                 seq = read_seqbegin(&neigh->ha_lock);
1331                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
1332                                       neigh->ha, NULL, skb->len);
1333         } while (read_seqretry(&neigh->ha_lock, seq));
1334 
1335         if (err >= 0)
1336                 err = dev_queue_xmit(skb);
1337         else {
1338                 err = -EINVAL;
1339                 kfree_skb(skb);
1340         }
1341         return err;
1342 }
1343 EXPORT_SYMBOL(neigh_connected_output);
1344 
1345 int neigh_direct_output(struct neighbour *neigh, struct sk_buff *skb)
1346 {
1347         return dev_queue_xmit(skb);
1348 }
1349 EXPORT_SYMBOL(neigh_direct_output);
1350 
1351 static void neigh_proxy_process(unsigned long arg)
1352 {
1353         struct neigh_table *tbl = (struct neigh_table *)arg;
1354         long sched_next = 0;
1355         unsigned long now = jiffies;
1356         struct sk_buff *skb, *n;
1357 
1358         spin_lock(&tbl->proxy_queue.lock);
1359 
1360         skb_queue_walk_safe(&tbl->proxy_queue, skb, n) {
1361                 long tdif = NEIGH_CB(skb)->sched_next - now;
1362 
1363                 if (tdif <= 0) {
1364                         struct net_device *dev = skb->dev;
1365 
1366                         __skb_unlink(skb, &tbl->proxy_queue);
1367                         if (tbl->proxy_redo && netif_running(dev)) {
1368                                 rcu_read_lock();
1369                                 tbl->proxy_redo(skb);
1370                                 rcu_read_unlock();
1371                         } else {
1372                                 kfree_skb(skb);
1373                         }
1374 
1375                         dev_put(dev);
1376                 } else if (!sched_next || tdif < sched_next)
1377                         sched_next = tdif;
1378         }
1379         del_timer(&tbl->proxy_timer);
1380         if (sched_next)
1381                 mod_timer(&tbl->proxy_timer, jiffies + sched_next);
1382         spin_unlock(&tbl->proxy_queue.lock);
1383 }
1384 
1385 void pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
1386                     struct sk_buff *skb)
1387 {
1388         unsigned long now = jiffies;
1389 
1390         unsigned long sched_next = now + (prandom_u32() %
1391                                           NEIGH_VAR(p, PROXY_DELAY));
1392 
1393         if (tbl->proxy_queue.qlen > NEIGH_VAR(p, PROXY_QLEN)) {
1394                 kfree_skb(skb);
1395                 return;
1396         }
1397 
1398         NEIGH_CB(skb)->sched_next = sched_next;
1399         NEIGH_CB(skb)->flags |= LOCALLY_ENQUEUED;
1400 
1401         spin_lock(&tbl->proxy_queue.lock);
1402         if (del_timer(&tbl->proxy_timer)) {
1403                 if (time_before(tbl->proxy_timer.expires, sched_next))
1404                         sched_next = tbl->proxy_timer.expires;
1405         }
1406         skb_dst_drop(skb);
1407         dev_hold(skb->dev);
1408         __skb_queue_tail(&tbl->proxy_queue, skb);
1409         mod_timer(&tbl->proxy_timer, sched_next);
1410         spin_unlock(&tbl->proxy_queue.lock);
1411 }
1412 EXPORT_SYMBOL(pneigh_enqueue);
1413 
1414 static inline struct neigh_parms *lookup_neigh_parms(struct neigh_table *tbl,
1415                                                       struct net *net, int ifindex)
1416 {
1417         struct neigh_parms *p;
1418 
1419         list_for_each_entry(p, &tbl->parms_list, list) {
1420                 if ((p->dev && p->dev->ifindex == ifindex && net_eq(neigh_parms_net(p), net)) ||
1421                     (!p->dev && !ifindex && net_eq(net, &init_net)))
1422                         return p;
1423         }
1424 
1425         return NULL;
1426 }
1427 
1428 struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
1429                                       struct neigh_table *tbl)
1430 {
1431         struct neigh_parms *p;
1432         struct net *net = dev_net(dev);
1433         const struct net_device_ops *ops = dev->netdev_ops;
1434 
1435         p = kmemdup(&tbl->parms, sizeof(*p), GFP_KERNEL);
1436         if (p) {
1437                 p->tbl            = tbl;
1438                 atomic_set(&p->refcnt, 1);
1439                 p->reachable_time =
1440                                 neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
1441                 dev_hold(dev);
1442                 p->dev = dev;
1443                 write_pnet(&p->net, net);
1444                 p->sysctl_table = NULL;
1445 
1446                 if (ops->ndo_neigh_setup && ops->ndo_neigh_setup(dev, p)) {
1447                         dev_put(dev);
1448                         kfree(p);
1449                         return NULL;
1450                 }
1451 
1452                 write_lock_bh(&tbl->lock);
1453                 list_add(&p->list, &tbl->parms.list);
1454                 write_unlock_bh(&tbl->lock);
1455 
1456                 neigh_parms_data_state_cleanall(p);
1457         }
1458         return p;
1459 }
1460 EXPORT_SYMBOL(neigh_parms_alloc);
1461 
1462 static void neigh_rcu_free_parms(struct rcu_head *head)
1463 {
1464         struct neigh_parms *parms =
1465                 container_of(head, struct neigh_parms, rcu_head);
1466 
1467         neigh_parms_put(parms);
1468 }
1469 
1470 void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms)
1471 {
1472         if (!parms || parms == &tbl->parms)
1473                 return;
1474         write_lock_bh(&tbl->lock);
1475         list_del(&parms->list);
1476         parms->dead = 1;
1477         write_unlock_bh(&tbl->lock);
1478         if (parms->dev)
1479                 dev_put(parms->dev);
1480         call_rcu(&parms->rcu_head, neigh_rcu_free_parms);
1481 }
1482 EXPORT_SYMBOL(neigh_parms_release);
1483 
1484 static void neigh_parms_destroy(struct neigh_parms *parms)
1485 {
1486         kfree(parms);
1487 }
1488 
1489 static struct lock_class_key neigh_table_proxy_queue_class;
1490 
1491 static struct neigh_table *neigh_tables[NEIGH_NR_TABLES] __read_mostly;
1492 
1493 void neigh_table_init(int index, struct neigh_table *tbl)
1494 {
1495         unsigned long now = jiffies;
1496         unsigned long phsize;
1497 
1498         INIT_LIST_HEAD(&tbl->parms_list);
1499         list_add(&tbl->parms.list, &tbl->parms_list);
1500         write_pnet(&tbl->parms.net, &init_net);
1501         atomic_set(&tbl->parms.refcnt, 1);
1502         tbl->parms.reachable_time =
1503                           neigh_rand_reach_time(NEIGH_VAR(&tbl->parms, BASE_REACHABLE_TIME));
1504 
1505         tbl->stats = alloc_percpu(struct neigh_statistics);
1506         if (!tbl->stats)
1507                 panic("cannot create neighbour cache statistics");
1508 
1509 #ifdef CONFIG_PROC_FS
1510         if (!proc_create_data(tbl->id, 0, init_net.proc_net_stat,
1511                               &neigh_stat_seq_fops, tbl))
1512                 panic("cannot create neighbour proc dir entry");
1513 #endif
1514 
1515         RCU_INIT_POINTER(tbl->nht, neigh_hash_alloc(3));
1516 
1517         phsize = (PNEIGH_HASHMASK + 1) * sizeof(struct pneigh_entry *);
1518         tbl->phash_buckets = kzalloc(phsize, GFP_KERNEL);
1519 
1520         if (!tbl->nht || !tbl->phash_buckets)
1521                 panic("cannot allocate neighbour cache hashes");
1522 
1523         if (!tbl->entry_size)
1524                 tbl->entry_size = ALIGN(offsetof(struct neighbour, primary_key) +
1525                                         tbl->key_len, NEIGH_PRIV_ALIGN);
1526         else
1527                 WARN_ON(tbl->entry_size % NEIGH_PRIV_ALIGN);
1528 
1529         rwlock_init(&tbl->lock);
1530         INIT_DEFERRABLE_WORK(&tbl->gc_work, neigh_periodic_work);
1531         queue_delayed_work(system_power_efficient_wq, &tbl->gc_work,
1532                         tbl->parms.reachable_time);
1533         setup_timer(&tbl->proxy_timer, neigh_proxy_process, (unsigned long)tbl);
1534         skb_queue_head_init_class(&tbl->proxy_queue,
1535                         &neigh_table_proxy_queue_class);
1536 
1537         tbl->last_flush = now;
1538         tbl->last_rand  = now + tbl->parms.reachable_time * 20;
1539 
1540         neigh_tables[index] = tbl;
1541 }
1542 EXPORT_SYMBOL(neigh_table_init);
1543 
1544 int neigh_table_clear(int index, struct neigh_table *tbl)
1545 {
1546         neigh_tables[index] = NULL;
1547         /* It is not clean... Fix it to unload IPv6 module safely */
1548         cancel_delayed_work_sync(&tbl->gc_work);
1549         del_timer_sync(&tbl->proxy_timer);
1550         pneigh_queue_purge(&tbl->proxy_queue);
1551         neigh_ifdown(tbl, NULL);
1552         if (atomic_read(&tbl->entries))
1553                 pr_crit("neighbour leakage\n");
1554 
1555         call_rcu(&rcu_dereference_protected(tbl->nht, 1)->rcu,
1556                  neigh_hash_free_rcu);
1557         tbl->nht = NULL;
1558 
1559         kfree(tbl->phash_buckets);
1560         tbl->phash_buckets = NULL;
1561 
1562         remove_proc_entry(tbl->id, init_net.proc_net_stat);
1563 
1564         free_percpu(tbl->stats);
1565         tbl->stats = NULL;
1566 
1567         return 0;
1568 }
1569 EXPORT_SYMBOL(neigh_table_clear);
1570 
1571 static struct neigh_table *neigh_find_table(int family)
1572 {
1573         struct neigh_table *tbl = NULL;
1574 
1575         switch (family) {
1576         case AF_INET:
1577                 tbl = neigh_tables[NEIGH_ARP_TABLE];
1578                 break;
1579         case AF_INET6:
1580                 tbl = neigh_tables[NEIGH_ND_TABLE];
1581                 break;
1582         case AF_DECnet:
1583                 tbl = neigh_tables[NEIGH_DN_TABLE];
1584                 break;
1585         }
1586 
1587         return tbl;
1588 }
1589 
1590 static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh)
1591 {
1592         struct net *net = sock_net(skb->sk);
1593         struct ndmsg *ndm;
1594         struct nlattr *dst_attr;
1595         struct neigh_table *tbl;
1596         struct neighbour *neigh;
1597         struct net_device *dev = NULL;
1598         int err = -EINVAL;
1599 
1600         ASSERT_RTNL();
1601         if (nlmsg_len(nlh) < sizeof(*ndm))
1602                 goto out;
1603 
1604         dst_attr = nlmsg_find_attr(nlh, sizeof(*ndm), NDA_DST);
1605         if (dst_attr == NULL)
1606                 goto out;
1607 
1608         ndm = nlmsg_data(nlh);
1609         if (ndm->ndm_ifindex) {
1610                 dev = __dev_get_by_index(net, ndm->ndm_ifindex);
1611                 if (dev == NULL) {
1612                         err = -ENODEV;
1613                         goto out;
1614                 }
1615         }
1616 
1617         tbl = neigh_find_table(ndm->ndm_family);
1618         if (tbl == NULL)
1619                 return -EAFNOSUPPORT;
1620 
1621         if (nla_len(dst_attr) < tbl->key_len)
1622                 goto out;
1623 
1624         if (ndm->ndm_flags & NTF_PROXY) {
1625                 err = pneigh_delete(tbl, net, nla_data(dst_attr), dev);
1626                 goto out;
1627         }
1628 
1629         if (dev == NULL)
1630                 goto out;
1631 
1632         neigh = neigh_lookup(tbl, nla_data(dst_attr), dev);
1633         if (neigh == NULL) {
1634                 err = -ENOENT;
1635                 goto out;
1636         }
1637 
1638         err = neigh_update(neigh, NULL, NUD_FAILED,
1639                            NEIGH_UPDATE_F_OVERRIDE |
1640                            NEIGH_UPDATE_F_ADMIN);
1641         neigh_release(neigh);
1642 
1643 out:
1644         return err;
1645 }
1646 
1647 static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh)
1648 {
1649         int flags = NEIGH_UPDATE_F_ADMIN | NEIGH_UPDATE_F_OVERRIDE;
1650         struct net *net = sock_net(skb->sk);
1651         struct ndmsg *ndm;
1652         struct nlattr *tb[NDA_MAX+1];
1653         struct neigh_table *tbl;
1654         struct net_device *dev = NULL;
1655         struct neighbour *neigh;
1656         void *dst, *lladdr;
1657         int err;
1658 
1659         ASSERT_RTNL();
1660         err = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, NULL);
1661         if (err < 0)
1662                 goto out;
1663 
1664         err = -EINVAL;
1665         if (tb[NDA_DST] == NULL)
1666                 goto out;
1667 
1668         ndm = nlmsg_data(nlh);
1669         if (ndm->ndm_ifindex) {
1670                 dev = __dev_get_by_index(net, ndm->ndm_ifindex);
1671                 if (dev == NULL) {
1672                         err = -ENODEV;
1673                         goto out;
1674                 }
1675 
1676                 if (tb[NDA_LLADDR] && nla_len(tb[NDA_LLADDR]) < dev->addr_len)
1677                         goto out;
1678         }
1679 
1680         tbl = neigh_find_table(ndm->ndm_family);
1681         if (tbl == NULL)
1682                 return -EAFNOSUPPORT;
1683 
1684         if (nla_len(tb[NDA_DST]) < tbl->key_len)
1685                 goto out;
1686         dst = nla_data(tb[NDA_DST]);
1687         lladdr = tb[NDA_LLADDR] ? nla_data(tb[NDA_LLADDR]) : NULL;
1688 
1689         if (ndm->ndm_flags & NTF_PROXY) {
1690                 struct pneigh_entry *pn;
1691 
1692                 err = -ENOBUFS;
1693                 pn = pneigh_lookup(tbl, net, dst, dev, 1);
1694                 if (pn) {
1695                         pn->flags = ndm->ndm_flags;
1696                         err = 0;
1697                 }
1698                 goto out;
1699         }
1700 
1701         if (dev == NULL)
1702                 goto out;
1703 
1704         neigh = neigh_lookup(tbl, dst, dev);
1705         if (neigh == NULL) {
1706                 if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
1707                         err = -ENOENT;
1708                         goto out;
1709                 }
1710 
1711                 neigh = __neigh_lookup_errno(tbl, dst, dev);
1712                 if (IS_ERR(neigh)) {
1713                         err = PTR_ERR(neigh);
1714                         goto out;
1715                 }
1716         } else {
1717                 if (nlh->nlmsg_flags & NLM_F_EXCL) {
1718                         err = -EEXIST;
1719                         neigh_release(neigh);
1720                         goto out;
1721                 }
1722 
1723                 if (!(nlh->nlmsg_flags & NLM_F_REPLACE))
1724                         flags &= ~NEIGH_UPDATE_F_OVERRIDE;
1725         }
1726 
1727         if (ndm->ndm_flags & NTF_USE) {
1728                 neigh_event_send(neigh, NULL);
1729                 err = 0;
1730         } else
1731                 err = neigh_update(neigh, lladdr, ndm->ndm_state, flags);
1732         neigh_release(neigh);
1733 
1734 out:
1735         return err;
1736 }
1737 
1738 static int neightbl_fill_parms(struct sk_buff *skb, struct neigh_parms *parms)
1739 {
1740         struct nlattr *nest;
1741 
1742         nest = nla_nest_start(skb, NDTA_PARMS);
1743         if (nest == NULL)
1744                 return -ENOBUFS;
1745 
1746         if ((parms->dev &&
1747              nla_put_u32(skb, NDTPA_IFINDEX, parms->dev->ifindex)) ||
1748             nla_put_u32(skb, NDTPA_REFCNT, atomic_read(&parms->refcnt)) ||
1749             nla_put_u32(skb, NDTPA_QUEUE_LENBYTES,
1750                         NEIGH_VAR(parms, QUEUE_LEN_BYTES)) ||
1751             /* approximative value for deprecated QUEUE_LEN (in packets) */
1752             nla_put_u32(skb, NDTPA_QUEUE_LEN,
1753                         NEIGH_VAR(parms, QUEUE_LEN_BYTES) / SKB_TRUESIZE(ETH_FRAME_LEN)) ||
1754             nla_put_u32(skb, NDTPA_PROXY_QLEN, NEIGH_VAR(parms, PROXY_QLEN)) ||
1755             nla_put_u32(skb, NDTPA_APP_PROBES, NEIGH_VAR(parms, APP_PROBES)) ||
1756             nla_put_u32(skb, NDTPA_UCAST_PROBES,
1757                         NEIGH_VAR(parms, UCAST_PROBES)) ||
1758             nla_put_u32(skb, NDTPA_MCAST_PROBES,
1759                         NEIGH_VAR(parms, MCAST_PROBES)) ||
1760             nla_put_u32(skb, NDTPA_MCAST_REPROBES,
1761                         NEIGH_VAR(parms, MCAST_REPROBES)) ||
1762             nla_put_msecs(skb, NDTPA_REACHABLE_TIME, parms->reachable_time,
1763                           NDTPA_PAD) ||
1764             nla_put_msecs(skb, NDTPA_BASE_REACHABLE_TIME,
1765                           NEIGH_VAR(parms, BASE_REACHABLE_TIME), NDTPA_PAD) ||
1766             nla_put_msecs(skb, NDTPA_GC_STALETIME,
1767                           NEIGH_VAR(parms, GC_STALETIME), NDTPA_PAD) ||
1768             nla_put_msecs(skb, NDTPA_DELAY_PROBE_TIME,
1769                           NEIGH_VAR(parms, DELAY_PROBE_TIME), NDTPA_PAD) ||
1770             nla_put_msecs(skb, NDTPA_RETRANS_TIME,
1771                           NEIGH_VAR(parms, RETRANS_TIME), NDTPA_PAD) ||
1772             nla_put_msecs(skb, NDTPA_ANYCAST_DELAY,
1773                           NEIGH_VAR(parms, ANYCAST_DELAY), NDTPA_PAD) ||
1774             nla_put_msecs(skb, NDTPA_PROXY_DELAY,
1775                           NEIGH_VAR(parms, PROXY_DELAY), NDTPA_PAD) ||
1776             nla_put_msecs(skb, NDTPA_LOCKTIME,
1777                           NEIGH_VAR(parms, LOCKTIME), NDTPA_PAD))
1778                 goto nla_put_failure;
1779         return nla_nest_end(skb, nest);
1780 
1781 nla_put_failure:
1782         nla_nest_cancel(skb, nest);
1783         return -EMSGSIZE;
1784 }
1785 
1786 static int neightbl_fill_info(struct sk_buff *skb, struct neigh_table *tbl,
1787                               u32 pid, u32 seq, int type, int flags)
1788 {
1789         struct nlmsghdr *nlh;
1790         struct ndtmsg *ndtmsg;
1791 
1792         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndtmsg), flags);
1793         if (nlh == NULL)
1794                 return -EMSGSIZE;
1795 
1796         ndtmsg = nlmsg_data(nlh);
1797 
1798         read_lock_bh(&tbl->lock);
1799         ndtmsg->ndtm_family = tbl->family;
1800         ndtmsg->ndtm_pad1   = 0;
1801         ndtmsg->ndtm_pad2   = 0;
1802 
1803         if (nla_put_string(skb, NDTA_NAME, tbl->id) ||
1804             nla_put_msecs(skb, NDTA_GC_INTERVAL, tbl->gc_interval, NDTA_PAD) ||
1805             nla_put_u32(skb, NDTA_THRESH1, tbl->gc_thresh1) ||
1806             nla_put_u32(skb, NDTA_THRESH2, tbl->gc_thresh2) ||
1807             nla_put_u32(skb, NDTA_THRESH3, tbl->gc_thresh3))
1808                 goto nla_put_failure;
1809         {
1810                 unsigned long now = jiffies;
1811                 unsigned int flush_delta = now - tbl->last_flush;
1812                 unsigned int rand_delta = now - tbl->last_rand;
1813                 struct neigh_hash_table *nht;
1814                 struct ndt_config ndc = {
1815                         .ndtc_key_len           = tbl->key_len,
1816                         .ndtc_entry_size        = tbl->entry_size,
1817                         .ndtc_entries           = atomic_read(&tbl->entries),
1818                         .ndtc_last_flush        = jiffies_to_msecs(flush_delta),
1819                         .ndtc_last_rand         = jiffies_to_msecs(rand_delta),
1820                         .ndtc_proxy_qlen        = tbl->proxy_queue.qlen,
1821                 };
1822 
1823                 rcu_read_lock_bh();
1824                 nht = rcu_dereference_bh(tbl->nht);
1825                 ndc.ndtc_hash_rnd = nht->hash_rnd[0];
1826                 ndc.ndtc_hash_mask = ((1 << nht->hash_shift) - 1);
1827                 rcu_read_unlock_bh();
1828 
1829                 if (nla_put(skb, NDTA_CONFIG, sizeof(ndc), &ndc))
1830                         goto nla_put_failure;
1831         }
1832 
1833         {
1834                 int cpu;
1835                 struct ndt_stats ndst;
1836 
1837                 memset(&ndst, 0, sizeof(ndst));
1838 
1839                 for_each_possible_cpu(cpu) {
1840                         struct neigh_statistics *st;
1841 
1842                         st = per_cpu_ptr(tbl->stats, cpu);
1843                         ndst.ndts_allocs                += st->allocs;
1844                         ndst.ndts_destroys              += st->destroys;
1845                         ndst.ndts_hash_grows            += st->hash_grows;
1846                         ndst.ndts_res_failed            += st->res_failed;
1847                         ndst.ndts_lookups               += st->lookups;
1848                         ndst.ndts_hits                  += st->hits;
1849                         ndst.ndts_rcv_probes_mcast      += st->rcv_probes_mcast;
1850                         ndst.ndts_rcv_probes_ucast      += st->rcv_probes_ucast;
1851                         ndst.ndts_periodic_gc_runs      += st->periodic_gc_runs;
1852                         ndst.ndts_forced_gc_runs        += st->forced_gc_runs;
1853                         ndst.ndts_table_fulls           += st->table_fulls;
1854                 }
1855 
1856                 if (nla_put_64bit(skb, NDTA_STATS, sizeof(ndst), &ndst,
1857                                   NDTA_PAD))
1858                         goto nla_put_failure;
1859         }
1860 
1861         BUG_ON(tbl->parms.dev);
1862         if (neightbl_fill_parms(skb, &tbl->parms) < 0)
1863                 goto nla_put_failure;
1864 
1865         read_unlock_bh(&tbl->lock);
1866         nlmsg_end(skb, nlh);
1867         return 0;
1868 
1869 nla_put_failure:
1870         read_unlock_bh(&tbl->lock);
1871         nlmsg_cancel(skb, nlh);
1872         return -EMSGSIZE;
1873 }
1874 
1875 static int neightbl_fill_param_info(struct sk_buff *skb,
1876                                     struct neigh_table *tbl,
1877                                     struct neigh_parms *parms,
1878                                     u32 pid, u32 seq, int type,
1879                                     unsigned int flags)
1880 {
1881         struct ndtmsg *ndtmsg;
1882         struct nlmsghdr *nlh;
1883 
1884         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndtmsg), flags);
1885         if (nlh == NULL)
1886                 return -EMSGSIZE;
1887 
1888         ndtmsg = nlmsg_data(nlh);
1889 
1890         read_lock_bh(&tbl->lock);
1891         ndtmsg->ndtm_family = tbl->family;
1892         ndtmsg->ndtm_pad1   = 0;
1893         ndtmsg->ndtm_pad2   = 0;
1894 
1895         if (nla_put_string(skb, NDTA_NAME, tbl->id) < 0 ||
1896             neightbl_fill_parms(skb, parms) < 0)
1897                 goto errout;
1898 
1899         read_unlock_bh(&tbl->lock);
1900         nlmsg_end(skb, nlh);
1901         return 0;
1902 errout:
1903         read_unlock_bh(&tbl->lock);
1904         nlmsg_cancel(skb, nlh);
1905         return -EMSGSIZE;
1906 }
1907 
1908 static const struct nla_policy nl_neightbl_policy[NDTA_MAX+1] = {
1909         [NDTA_NAME]             = { .type = NLA_STRING },
1910         [NDTA_THRESH1]          = { .type = NLA_U32 },
1911         [NDTA_THRESH2]          = { .type = NLA_U32 },
1912         [NDTA_THRESH3]          = { .type = NLA_U32 },
1913         [NDTA_GC_INTERVAL]      = { .type = NLA_U64 },
1914         [NDTA_PARMS]            = { .type = NLA_NESTED },
1915 };
1916 
1917 static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {
1918         [NDTPA_IFINDEX]                 = { .type = NLA_U32 },
1919         [NDTPA_QUEUE_LEN]               = { .type = NLA_U32 },
1920         [NDTPA_PROXY_QLEN]              = { .type = NLA_U32 },
1921         [NDTPA_APP_PROBES]              = { .type = NLA_U32 },
1922         [NDTPA_UCAST_PROBES]            = { .type = NLA_U32 },
1923         [NDTPA_MCAST_PROBES]            = { .type = NLA_U32 },
1924         [NDTPA_MCAST_REPROBES]          = { .type = NLA_U32 },
1925         [NDTPA_BASE_REACHABLE_TIME]     = { .type = NLA_U64 },
1926         [NDTPA_GC_STALETIME]            = { .type = NLA_U64 },
1927         [NDTPA_DELAY_PROBE_TIME]        = { .type = NLA_U64 },
1928         [NDTPA_RETRANS_TIME]            = { .type = NLA_U64 },
1929         [NDTPA_ANYCAST_DELAY]           = { .type = NLA_U64 },
1930         [NDTPA_PROXY_DELAY]             = { .type = NLA_U64 },
1931         [NDTPA_LOCKTIME]                = { .type = NLA_U64 },
1932 };
1933 
1934 static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh)
1935 {
1936         struct net *net = sock_net(skb->sk);
1937         struct neigh_table *tbl;
1938         struct ndtmsg *ndtmsg;
1939         struct nlattr *tb[NDTA_MAX+1];
1940         bool found = false;
1941         int err, tidx;
1942 
1943         err = nlmsg_parse(nlh, sizeof(*ndtmsg), tb, NDTA_MAX,
1944                           nl_neightbl_policy);
1945         if (err < 0)
1946                 goto errout;
1947 
1948         if (tb[NDTA_NAME] == NULL) {
1949                 err = -EINVAL;
1950                 goto errout;
1951         }
1952 
1953         ndtmsg = nlmsg_data(nlh);
1954 
1955         for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
1956                 tbl = neigh_tables[tidx];
1957                 if (!tbl)
1958                         continue;
1959                 if (ndtmsg->ndtm_family && tbl->family != ndtmsg->ndtm_family)
1960                         continue;
1961                 if (nla_strcmp(tb[NDTA_NAME], tbl->id) == 0) {
1962                         found = true;
1963                         break;
1964                 }
1965         }
1966 
1967         if (!found)
1968                 return -ENOENT;
1969 
1970         /*
1971          * We acquire tbl->lock to be nice to the periodic timers and
1972          * make sure they always see a consistent set of values.
1973          */
1974         write_lock_bh(&tbl->lock);
1975 
1976         if (tb[NDTA_PARMS]) {
1977                 struct nlattr *tbp[NDTPA_MAX+1];
1978                 struct neigh_parms *p;
1979                 int i, ifindex = 0;
1980 
1981                 err = nla_parse_nested(tbp, NDTPA_MAX, tb[NDTA_PARMS],
1982                                        nl_ntbl_parm_policy);
1983                 if (err < 0)
1984                         goto errout_tbl_lock;
1985 
1986                 if (tbp[NDTPA_IFINDEX])
1987                         ifindex = nla_get_u32(tbp[NDTPA_IFINDEX]);
1988 
1989                 p = lookup_neigh_parms(tbl, net, ifindex);
1990                 if (p == NULL) {
1991                         err = -ENOENT;
1992                         goto errout_tbl_lock;
1993                 }
1994 
1995                 for (i = 1; i <= NDTPA_MAX; i++) {
1996                         if (tbp[i] == NULL)
1997                                 continue;
1998 
1999                         switch (i) {
2000                         case NDTPA_QUEUE_LEN:
2001                                 NEIGH_VAR_SET(p, QUEUE_LEN_BYTES,
2002                                               nla_get_u32(tbp[i]) *
2003                                               SKB_TRUESIZE(ETH_FRAME_LEN));
2004                                 break;
2005                         case NDTPA_QUEUE_LENBYTES:
2006                                 NEIGH_VAR_SET(p, QUEUE_LEN_BYTES,
2007                                               nla_get_u32(tbp[i]));
2008                                 break;
2009                         case NDTPA_PROXY_QLEN:
2010                                 NEIGH_VAR_SET(p, PROXY_QLEN,
2011                                               nla_get_u32(tbp[i]));
2012                                 break;
2013                         case NDTPA_APP_PROBES:
2014                                 NEIGH_VAR_SET(p, APP_PROBES,
2015                                               nla_get_u32(tbp[i]));
2016                                 break;
2017                         case NDTPA_UCAST_PROBES:
2018                                 NEIGH_VAR_SET(p, UCAST_PROBES,
2019                                               nla_get_u32(tbp[i]));
2020                                 break;
2021                         case NDTPA_MCAST_PROBES:
2022                                 NEIGH_VAR_SET(p, MCAST_PROBES,
2023                                               nla_get_u32(tbp[i]));
2024                                 break;
2025                         case NDTPA_MCAST_REPROBES:
2026                                 NEIGH_VAR_SET(p, MCAST_REPROBES,
2027                                               nla_get_u32(tbp[i]));
2028                                 break;
2029                         case NDTPA_BASE_REACHABLE_TIME:
2030                                 NEIGH_VAR_SET(p, BASE_REACHABLE_TIME,
2031                                               nla_get_msecs(tbp[i]));
2032                                 /* update reachable_time as well, otherwise, the change will
2033                                  * only be effective after the next time neigh_periodic_work
2034                                  * decides to recompute it (can be multiple minutes)
2035                                  */
2036                                 p->reachable_time =
2037                                         neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
2038                                 break;
2039                         case NDTPA_GC_STALETIME:
2040                                 NEIGH_VAR_SET(p, GC_STALETIME,
2041                                               nla_get_msecs(tbp[i]));
2042                                 break;
2043                         case NDTPA_DELAY_PROBE_TIME:
2044                                 NEIGH_VAR_SET(p, DELAY_PROBE_TIME,
2045                                               nla_get_msecs(tbp[i]));
2046                                 call_netevent_notifiers(NETEVENT_DELAY_PROBE_TIME_UPDATE, p);
2047                                 break;
2048                         case NDTPA_RETRANS_TIME:
2049                                 NEIGH_VAR_SET(p, RETRANS_TIME,
2050                                               nla_get_msecs(tbp[i]));
2051                                 break;
2052                         case NDTPA_ANYCAST_DELAY:
2053                                 NEIGH_VAR_SET(p, ANYCAST_DELAY,
2054                                               nla_get_msecs(tbp[i]));
2055                                 break;
2056                         case NDTPA_PROXY_DELAY:
2057                                 NEIGH_VAR_SET(p, PROXY_DELAY,
2058                                               nla_get_msecs(tbp[i]));
2059                                 break;
2060                         case NDTPA_LOCKTIME:
2061                                 NEIGH_VAR_SET(p, LOCKTIME,
2062                                               nla_get_msecs(tbp[i]));
2063                                 break;
2064                         }
2065                 }
2066         }
2067 
2068         err = -ENOENT;
2069         if ((tb[NDTA_THRESH1] || tb[NDTA_THRESH2] ||
2070              tb[NDTA_THRESH3] || tb[NDTA_GC_INTERVAL]) &&
2071             !net_eq(net, &init_net))
2072                 goto errout_tbl_lock;
2073 
2074         if (tb[NDTA_THRESH1])
2075                 tbl->gc_thresh1 = nla_get_u32(tb[NDTA_THRESH1]);
2076 
2077         if (tb[NDTA_THRESH2])
2078                 tbl->gc_thresh2 = nla_get_u32(tb[NDTA_THRESH2]);
2079 
2080         if (tb[NDTA_THRESH3])
2081                 tbl->gc_thresh3 = nla_get_u32(tb[NDTA_THRESH3]);
2082 
2083         if (tb[NDTA_GC_INTERVAL])
2084                 tbl->gc_interval = nla_get_msecs(tb[NDTA_GC_INTERVAL]);
2085 
2086         err = 0;
2087 
2088 errout_tbl_lock:
2089         write_unlock_bh(&tbl->lock);
2090 errout:
2091         return err;
2092 }
2093 
2094 static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
2095 {
2096         struct net *net = sock_net(skb->sk);
2097         int family, tidx, nidx = 0;
2098         int tbl_skip = cb->args[0];
2099         int neigh_skip = cb->args[1];
2100         struct neigh_table *tbl;
2101 
2102         family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
2103 
2104         for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
2105                 struct neigh_parms *p;
2106 
2107                 tbl = neigh_tables[tidx];
2108                 if (!tbl)
2109                         continue;
2110 
2111                 if (tidx < tbl_skip || (family && tbl->family != family))
2112                         continue;
2113 
2114                 if (neightbl_fill_info(skb, tbl, NETLINK_CB(cb->skb).portid,
2115                                        cb->nlh->nlmsg_seq, RTM_NEWNEIGHTBL,
2116                                        NLM_F_MULTI) < 0)
2117                         break;
2118 
2119                 nidx = 0;
2120                 p = list_next_entry(&tbl->parms, list);
2121                 list_for_each_entry_from(p, &tbl->parms_list, list) {
2122                         if (!net_eq(neigh_parms_net(p), net))
2123                                 continue;
2124 
2125                         if (nidx < neigh_skip)
2126                                 goto next;
2127 
2128                         if (neightbl_fill_param_info(skb, tbl, p,
2129                                                      NETLINK_CB(cb->skb).portid,
2130                                                      cb->nlh->nlmsg_seq,
2131                                                      RTM_NEWNEIGHTBL,
2132                                                      NLM_F_MULTI) < 0)
2133                                 goto out;
2134                 next:
2135                         nidx++;
2136                 }
2137 
2138                 neigh_skip = 0;
2139         }
2140 out:
2141         cb->args[0] = tidx;
2142         cb->args[1] = nidx;
2143 
2144         return skb->len;
2145 }
2146 
2147 static int neigh_fill_info(struct sk_buff *skb, struct neighbour *neigh,
2148                            u32 pid, u32 seq, int type, unsigned int flags)
2149 {
2150         unsigned long now = jiffies;
2151         struct nda_cacheinfo ci;
2152         struct nlmsghdr *nlh;
2153         struct ndmsg *ndm;
2154 
2155         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
2156         if (nlh == NULL)
2157                 return -EMSGSIZE;
2158 
2159         ndm = nlmsg_data(nlh);
2160         ndm->ndm_family  = neigh->ops->family;
2161         ndm->ndm_pad1    = 0;
2162         ndm->ndm_pad2    = 0;
2163         ndm->ndm_flags   = neigh->flags;
2164         ndm->ndm_type    = neigh->type;
2165         ndm->ndm_ifindex = neigh->dev->ifindex;
2166 
2167         if (nla_put(skb, NDA_DST, neigh->tbl->key_len, neigh->primary_key))
2168                 goto nla_put_failure;
2169 
2170         read_lock_bh(&neigh->lock);
2171         ndm->ndm_state   = neigh->nud_state;
2172         if (neigh->nud_state & NUD_VALID) {
2173                 char haddr[MAX_ADDR_LEN];
2174 
2175                 neigh_ha_snapshot(haddr, neigh, neigh->dev);
2176                 if (nla_put(skb, NDA_LLADDR, neigh->dev->addr_len, haddr) < 0) {
2177                         read_unlock_bh(&neigh->lock);
2178                         goto nla_put_failure;
2179                 }
2180         }
2181 
2182         ci.ndm_used      = jiffies_to_clock_t(now - neigh->used);
2183         ci.ndm_confirmed = jiffies_to_clock_t(now - neigh->confirmed);
2184         ci.ndm_updated   = jiffies_to_clock_t(now - neigh->updated);
2185         ci.ndm_refcnt    = atomic_read(&neigh->refcnt) - 1;
2186         read_unlock_bh(&neigh->lock);
2187 
2188         if (nla_put_u32(skb, NDA_PROBES, atomic_read(&neigh->probes)) ||
2189             nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
2190                 goto nla_put_failure;
2191 
2192         nlmsg_end(skb, nlh);
2193         return 0;
2194 
2195 nla_put_failure:
2196         nlmsg_cancel(skb, nlh);
2197         return -EMSGSIZE;
2198 }
2199 
2200 static int pneigh_fill_info(struct sk_buff *skb, struct pneigh_entry *pn,
2201                             u32 pid, u32 seq, int type, unsigned int flags,
2202                             struct neigh_table *tbl)
2203 {
2204         struct nlmsghdr *nlh;
2205         struct ndmsg *ndm;
2206 
2207         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
2208         if (nlh == NULL)
2209                 return -EMSGSIZE;
2210 
2211         ndm = nlmsg_data(nlh);
2212         ndm->ndm_family  = tbl->family;
2213         ndm->ndm_pad1    = 0;
2214         ndm->ndm_pad2    = 0;
2215         ndm->ndm_flags   = pn->flags | NTF_PROXY;
2216         ndm->ndm_type    = RTN_UNICAST;
2217         ndm->ndm_ifindex = pn->dev ? pn->dev->ifindex : 0;
2218         ndm->ndm_state   = NUD_NONE;
2219 
2220         if (nla_put(skb, NDA_DST, tbl->key_len, pn->key))
2221                 goto nla_put_failure;
2222 
2223         nlmsg_end(skb, nlh);
2224         return 0;
2225 
2226 nla_put_failure:
2227         nlmsg_cancel(skb, nlh);
2228         return -EMSGSIZE;
2229 }
2230 
2231 static void neigh_update_notify(struct neighbour *neigh)
2232 {
2233         call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, neigh);
2234         __neigh_notify(neigh, RTM_NEWNEIGH, 0);
2235 }
2236 
2237 static bool neigh_master_filtered(struct net_device *dev, int master_idx)
2238 {
2239         struct net_device *master;
2240 
2241         if (!master_idx)
2242                 return false;
2243 
2244         master = netdev_master_upper_dev_get(dev);
2245         if (!master || master->ifindex != master_idx)
2246                 return true;
2247 
2248         return false;
2249 }
2250 
2251 static bool neigh_ifindex_filtered(struct net_device *dev, int filter_idx)
2252 {
2253         if (filter_idx && dev->ifindex != filter_idx)
2254                 return true;
2255 
2256         return false;
2257 }
2258 
2259 static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
2260                             struct netlink_callback *cb)
2261 {
2262         struct net *net = sock_net(skb->sk);
2263         const struct nlmsghdr *nlh = cb->nlh;
2264         struct nlattr *tb[NDA_MAX + 1];
2265         struct neighbour *n;
2266         int rc, h, s_h = cb->args[1];
2267         int idx, s_idx = idx = cb->args[2];
2268         struct neigh_hash_table *nht;
2269         int filter_master_idx = 0, filter_idx = 0;
2270         unsigned int flags = NLM_F_MULTI;
2271         int err;
2272 
2273         err = nlmsg_parse(nlh, sizeof(struct ndmsg), tb, NDA_MAX, NULL);
2274         if (!err) {
2275                 if (tb[NDA_IFINDEX])
2276                         filter_idx = nla_get_u32(tb[NDA_IFINDEX]);
2277 
2278                 if (tb[NDA_MASTER])
2279                         filter_master_idx = nla_get_u32(tb[NDA_MASTER]);
2280 
2281                 if (filter_idx || filter_master_idx)
2282                         flags |= NLM_F_DUMP_FILTERED;
2283         }
2284 
2285         rcu_read_lock_bh();
2286         nht = rcu_dereference_bh(tbl->nht);
2287 
2288         for (h = s_h; h < (1 << nht->hash_shift); h++) {
2289                 if (h > s_h)
2290                         s_idx = 0;
2291                 for (n = rcu_dereference_bh(nht->hash_buckets[h]), idx = 0;
2292                      n != NULL;
2293                      n = rcu_dereference_bh(n->next)) {
2294                         if (!net_eq(dev_net(n->dev), net))
2295                                 continue;
2296                         if (neigh_ifindex_filtered(n->dev, filter_idx))
2297                                 continue;
2298                         if (neigh_master_filtered(n->dev, filter_master_idx))
2299                                 continue;
2300                         if (idx < s_idx)
2301                                 goto next;
2302                         if (neigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
2303                                             cb->nlh->nlmsg_seq,
2304                                             RTM_NEWNEIGH,
2305                                             flags) < 0) {
2306                                 rc = -1;
2307                                 goto out;
2308                         }
2309 next:
2310                         idx++;
2311                 }
2312         }
2313         rc = skb->len;
2314 out:
2315         rcu_read_unlock_bh();
2316         cb->args[1] = h;
2317         cb->args[2] = idx;
2318         return rc;
2319 }
2320 
2321 static int pneigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
2322                              struct netlink_callback *cb)
2323 {
2324         struct pneigh_entry *n;
2325         struct net *net = sock_net(skb->sk);
2326         int rc, h, s_h = cb->args[3];
2327         int idx, s_idx = idx = cb->args[4];
2328 
2329         read_lock_bh(&tbl->lock);
2330 
2331         for (h = s_h; h <= PNEIGH_HASHMASK; h++) {
2332                 if (h > s_h)
2333                         s_idx = 0;
2334                 for (n = tbl->phash_buckets[h], idx = 0; n; n = n->next) {
2335                         if (pneigh_net(n) != net)
2336                                 continue;
2337                         if (idx < s_idx)
2338                                 goto next;
2339                         if (pneigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
2340                                             cb->nlh->nlmsg_seq,
2341                                             RTM_NEWNEIGH,
2342                                             NLM_F_MULTI, tbl) < 0) {
2343                                 read_unlock_bh(&tbl->lock);
2344                                 rc = -1;
2345                                 goto out;
2346                         }
2347                 next:
2348                         idx++;
2349                 }
2350         }
2351 
2352         read_unlock_bh(&tbl->lock);
2353         rc = skb->len;
2354 out:
2355         cb->args[3] = h;
2356         cb->args[4] = idx;
2357         return rc;
2358 
2359 }
2360 
2361 static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
2362 {
2363         struct neigh_table *tbl;
2364         int t, family, s_t;
2365         int proxy = 0;
2366         int err;
2367 
2368         family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
2369 
2370         /* check for full ndmsg structure presence, family member is
2371          * the same for both structures
2372          */
2373         if (nlmsg_len(cb->nlh) >= sizeof(struct ndmsg) &&
2374             ((struct ndmsg *) nlmsg_data(cb->nlh))->ndm_flags == NTF_PROXY)
2375                 proxy = 1;
2376 
2377         s_t = cb->args[0];
2378 
2379         for (t = 0; t < NEIGH_NR_TABLES; t++) {
2380                 tbl = neigh_tables[t];
2381 
2382                 if (!tbl)
2383                         continue;
2384                 if (t < s_t || (family && tbl->family != family))
2385                         continue;
2386                 if (t > s_t)
2387                         memset(&cb->args[1], 0, sizeof(cb->args) -
2388                                                 sizeof(cb->args[0]));
2389                 if (proxy)
2390                         err = pneigh_dump_table(tbl, skb, cb);
2391                 else
2392                         err = neigh_dump_table(tbl, skb, cb);
2393                 if (err < 0)
2394                         break;
2395         }
2396 
2397         cb->args[0] = t;
2398         return skb->len;
2399 }
2400 
2401 void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie)
2402 {
2403         int chain;
2404         struct neigh_hash_table *nht;
2405 
2406         rcu_read_lock_bh();
2407         nht = rcu_dereference_bh(tbl->nht);
2408 
2409         read_lock(&tbl->lock); /* avoid resizes */
2410         for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
2411                 struct neighbour *n;
2412 
2413                 for (n = rcu_dereference_bh(nht->hash_buckets[chain]);
2414                      n != NULL;
2415                      n = rcu_dereference_bh(n->next))
2416                         cb(n, cookie);
2417         }
2418         read_unlock(&tbl->lock);
2419         rcu_read_unlock_bh();
2420 }
2421 EXPORT_SYMBOL(neigh_for_each);
2422 
2423 /* The tbl->lock must be held as a writer and BH disabled. */
2424 void __neigh_for_each_release(struct neigh_table *tbl,
2425                               int (*cb)(struct neighbour *))
2426 {
2427         int chain;
2428         struct neigh_hash_table *nht;
2429 
2430         nht = rcu_dereference_protected(tbl->nht,
2431                                         lockdep_is_held(&tbl->lock));
2432         for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
2433                 struct neighbour *n;
2434                 struct neighbour __rcu **np;
2435 
2436                 np = &nht->hash_buckets[chain];
2437                 while ((n = rcu_dereference_protected(*np,
2438                                         lockdep_is_held(&tbl->lock))) != NULL) {
2439                         int release;
2440 
2441                         write_lock(&n->lock);
2442                         release = cb(n);
2443                         if (release) {
2444                                 rcu_assign_pointer(*np,
2445                                         rcu_dereference_protected(n->next,
2446                                                 lockdep_is_held(&tbl->lock)));
2447                                 n->dead = 1;
2448                         } else
2449                                 np = &n->next;
2450                         write_unlock(&n->lock);
2451                         if (release)
2452                                 neigh_cleanup_and_release(n);
2453                 }
2454         }
2455 }
2456 EXPORT_SYMBOL(__neigh_for_each_release);
2457 
2458 int neigh_xmit(int index, struct net_device *dev,
2459                const void *addr, struct sk_buff *skb)
2460 {
2461         int err = -EAFNOSUPPORT;
2462         if (likely(index < NEIGH_NR_TABLES)) {
2463                 struct neigh_table *tbl;
2464                 struct neighbour *neigh;
2465 
2466                 tbl = neigh_tables[index];
2467                 if (!tbl)
2468                         goto out;
2469                 rcu_read_lock_bh();
2470                 neigh = __neigh_lookup_noref(tbl, addr, dev);
2471                 if (!neigh)
2472                         neigh = __neigh_create(tbl, addr, dev, false);
2473                 err = PTR_ERR(neigh);
2474                 if (IS_ERR(neigh)) {
2475                         rcu_read_unlock_bh();
2476                         goto out_kfree_skb;
2477                 }
2478                 err = neigh->output(neigh, skb);
2479                 rcu_read_unlock_bh();
2480         }
2481         else if (index == NEIGH_LINK_TABLE) {
2482                 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
2483                                       addr, NULL, skb->len);
2484                 if (err < 0)
2485                         goto out_kfree_skb;
2486                 err = dev_queue_xmit(skb);
2487         }
2488 out:
2489         return err;
2490 out_kfree_skb:
2491         kfree_skb(skb);
2492         goto out;
2493 }
2494 EXPORT_SYMBOL(neigh_xmit);
2495 
2496 #ifdef CONFIG_PROC_FS
2497 
2498 static struct neighbour *neigh_get_first(struct seq_file *seq)
2499 {
2500         struct neigh_seq_state *state = seq->private;
2501         struct net *net = seq_file_net(seq);
2502         struct neigh_hash_table *nht = state->nht;
2503         struct neighbour *n = NULL;
2504         int bucket = state->bucket;
2505 
2506         state->flags &= ~NEIGH_SEQ_IS_PNEIGH;
2507         for (bucket = 0; bucket < (1 << nht->hash_shift); bucket++) {
2508                 n = rcu_dereference_bh(nht->hash_buckets[bucket]);
2509 
2510                 while (n) {
2511                         if (!net_eq(dev_net(n->dev), net))
2512                                 goto next;
2513                         if (state->neigh_sub_iter) {
2514                                 loff_t fakep = 0;
2515                                 void *v;
2516 
2517                                 v = state->neigh_sub_iter(state, n, &fakep);
2518                                 if (!v)
2519                                         goto next;
2520                         }
2521                         if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
2522                                 break;
2523                         if (n->nud_state & ~NUD_NOARP)
2524                                 break;
2525 next:
2526                         n = rcu_dereference_bh(n->next);
2527                 }
2528 
2529                 if (n)
2530                         break;
2531         }
2532         state->bucket = bucket;
2533 
2534         return n;
2535 }
2536 
2537 static struct neighbour *neigh_get_next(struct seq_file *seq,
2538                                         struct neighbour *n,
2539                                         loff_t *pos)
2540 {
2541         struct neigh_seq_state *state = seq->private;
2542         struct net *net = seq_file_net(seq);
2543         struct neigh_hash_table *nht = state->nht;
2544 
2545         if (state->neigh_sub_iter) {
2546                 void *v = state->neigh_sub_iter(state, n, pos);
2547                 if (v)
2548                         return n;
2549         }
2550         n = rcu_dereference_bh(n->next);
2551 
2552         while (1) {
2553                 while (n) {
2554                         if (!net_eq(dev_net(n->dev), net))
2555                                 goto next;
2556                         if (state->neigh_sub_iter) {
2557                                 void *v = state->neigh_sub_iter(state, n, pos);
2558                                 if (v)
2559                                         return n;
2560                                 goto next;
2561                         }
2562                         if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
2563                                 break;
2564 
2565                         if (n->nud_state & ~NUD_NOARP)
2566                                 break;
2567 next:
2568                         n = rcu_dereference_bh(n->next);
2569                 }
2570 
2571                 if (n)
2572                         break;
2573 
2574                 if (++state->bucket >= (1 << nht->hash_shift))
2575                         break;
2576 
2577                 n = rcu_dereference_bh(nht->hash_buckets[state->bucket]);
2578         }
2579 
2580         if (n && pos)
2581                 --(*pos);
2582         return n;
2583 }
2584 
2585 static struct neighbour *neigh_get_idx(struct seq_file *seq, loff_t *pos)
2586 {
2587         struct neighbour *n = neigh_get_first(seq);
2588 
2589         if (n) {
2590                 --(*pos);
2591                 while (*pos) {
2592                         n = neigh_get_next(seq, n, pos);
2593                         if (!n)
2594                                 break;
2595                 }
2596         }
2597         return *pos ? NULL : n;
2598 }
2599 
2600 static struct pneigh_entry *pneigh_get_first(struct seq_file *seq)
2601 {
2602         struct neigh_seq_state *state = seq->private;
2603         struct net *net = seq_file_net(seq);
2604         struct neigh_table *tbl = state->tbl;
2605         struct pneigh_entry *pn = NULL;
2606         int bucket = state->bucket;
2607 
2608         state->flags |= NEIGH_SEQ_IS_PNEIGH;
2609         for (bucket = 0; bucket <= PNEIGH_HASHMASK; bucket++) {
2610                 pn = tbl->phash_buckets[bucket];
2611                 while (pn && !net_eq(pneigh_net(pn), net))
2612                         pn = pn->next;
2613                 if (pn)
2614                         break;
2615         }
2616         state->bucket = bucket;
2617 
2618         return pn;
2619 }
2620 
2621 static struct pneigh_entry *pneigh_get_next(struct seq_file *seq,
2622                                             struct pneigh_entry *pn,
2623                                             loff_t *pos)
2624 {
2625         struct neigh_seq_state *state = seq->private;
2626         struct net *net = seq_file_net(seq);
2627         struct neigh_table *tbl = state->tbl;
2628 
2629         do {
2630                 pn = pn->next;
2631         } while (pn && !net_eq(pneigh_net(pn), net));
2632 
2633         while (!pn) {
2634                 if (++state->bucket > PNEIGH_HASHMASK)
2635                         break;
2636                 pn = tbl->phash_buckets[state->bucket];
2637                 while (pn && !net_eq(pneigh_net(pn), net))
2638                         pn = pn->next;
2639                 if (pn)
2640                         break;
2641         }
2642 
2643         if (pn && pos)
2644                 --(*pos);
2645 
2646         return pn;
2647 }
2648 
2649 static struct pneigh_entry *pneigh_get_idx(struct seq_file *seq, loff_t *pos)
2650 {
2651         struct pneigh_entry *pn = pneigh_get_first(seq);
2652 
2653         if (pn) {
2654                 --(*pos);
2655                 while (*pos) {
2656                         pn = pneigh_get_next(seq, pn, pos);
2657                         if (!pn)
2658                                 break;
2659                 }
2660         }
2661         return *pos ? NULL : pn;
2662 }
2663 
2664 static void *neigh_get_idx_any(struct seq_file *seq, loff_t *pos)
2665 {
2666         struct neigh_seq_state *state = seq->private;
2667         void *rc;
2668         loff_t idxpos = *pos;
2669 
2670         rc = neigh_get_idx(seq, &idxpos);
2671         if (!rc && !(state->flags & NEIGH_SEQ_NEIGH_ONLY))
2672                 rc = pneigh_get_idx(seq, &idxpos);
2673 
2674         return rc;
2675 }
2676 
2677 void *neigh_seq_start(struct seq_file *seq, loff_t *pos, struct neigh_table *tbl, unsigned int neigh_seq_flags)
2678         __acquires(rcu_bh)
2679 {
2680         struct neigh_seq_state *state = seq->private;
2681 
2682         state->tbl = tbl;
2683         state->bucket = 0;
2684         state->flags = (neigh_seq_flags & ~NEIGH_SEQ_IS_PNEIGH);
2685 
2686         rcu_read_lock_bh();
2687         state->nht = rcu_dereference_bh(tbl->nht);
2688 
2689         return *pos ? neigh_get_idx_any(seq, pos) : SEQ_START_TOKEN;
2690 }
2691 EXPORT_SYMBOL(neigh_seq_start);
2692 
2693 void *neigh_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2694 {
2695         struct neigh_seq_state *state;
2696         void *rc;
2697 
2698         if (v == SEQ_START_TOKEN) {
2699                 rc = neigh_get_first(seq);
2700                 goto out;
2701         }
2702 
2703         state = seq->private;
2704         if (!(state->flags & NEIGH_SEQ_IS_PNEIGH)) {
2705                 rc = neigh_get_next(seq, v, NULL);
2706                 if (rc)
2707                         goto out;
2708                 if (!(state->flags & NEIGH_SEQ_NEIGH_ONLY))
2709                         rc = pneigh_get_first(seq);
2710         } else {
2711                 BUG_ON(state->flags & NEIGH_SEQ_NEIGH_ONLY);
2712                 rc = pneigh_get_next(seq, v, NULL);
2713         }
2714 out:
2715         ++(*pos);
2716         return rc;
2717 }
2718 EXPORT_SYMBOL(neigh_seq_next);
2719 
2720 void neigh_seq_stop(struct seq_file *seq, void *v)
2721         __releases(rcu_bh)
2722 {
2723         rcu_read_unlock_bh();
2724 }
2725 EXPORT_SYMBOL(neigh_seq_stop);
2726 
2727 /* statistics via seq_file */
2728 
2729 static void *neigh_stat_seq_start(struct seq_file *seq, loff_t *pos)
2730 {
2731         struct neigh_table *tbl = seq->private;
2732         int cpu;
2733 
2734         if (*pos == 0)
2735                 return SEQ_START_TOKEN;
2736 
2737         for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
2738                 if (!cpu_possible(cpu))
2739                         continue;
2740                 *pos = cpu+1;
2741                 return per_cpu_ptr(tbl->stats, cpu);
2742         }
2743         return NULL;
2744 }
2745 
2746 static void *neigh_stat_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2747 {
2748         struct neigh_table *tbl = seq->private;
2749         int cpu;
2750 
2751         for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
2752                 if (!cpu_possible(cpu))
2753                         continue;
2754                 *pos = cpu+1;
2755                 return per_cpu_ptr(tbl->stats, cpu);
2756         }
2757         return NULL;
2758 }
2759 
2760 static void neigh_stat_seq_stop(struct seq_file *seq, void *v)
2761 {
2762 
2763 }
2764 
2765 static int neigh_stat_seq_show(struct seq_file *seq, void *v)
2766 {
2767         struct neigh_table *tbl = seq->private;
2768         struct neigh_statistics *st = v;
2769 
2770         if (v == SEQ_START_TOKEN) {
2771                 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");
2772                 return 0;
2773         }
2774 
2775         seq_printf(seq, "%08x  %08lx %08lx %08lx  %08lx %08lx  %08lx  "
2776                         "%08lx %08lx  %08lx %08lx %08lx %08lx\n",
2777                    atomic_read(&tbl->entries),
2778 
2779                    st->allocs,
2780                    st->destroys,
2781                    st->hash_grows,
2782 
2783                    st->lookups,
2784                    st->hits,
2785 
2786                    st->res_failed,
2787 
2788                    st->rcv_probes_mcast,
2789                    st->rcv_probes_ucast,
2790 
2791                    st->periodic_gc_runs,
2792                    st->forced_gc_runs,
2793                    st->unres_discards,
2794                    st->table_fulls
2795                    );
2796 
2797         return 0;
2798 }
2799 
2800 static const struct seq_operations neigh_stat_seq_ops = {
2801         .start  = neigh_stat_seq_start,
2802         .next   = neigh_stat_seq_next,
2803         .stop   = neigh_stat_seq_stop,
2804         .show   = neigh_stat_seq_show,
2805 };
2806 
2807 static int neigh_stat_seq_open(struct inode *inode, struct file *file)
2808 {
2809         int ret = seq_open(file, &neigh_stat_seq_ops);
2810 
2811         if (!ret) {
2812                 struct seq_file *sf = file->private_data;
2813                 sf->private = PDE_DATA(inode);
2814         }
2815         return ret;
2816 };
2817 
2818 static const struct file_operations neigh_stat_seq_fops = {
2819         .owner   = THIS_MODULE,
2820         .open    = neigh_stat_seq_open,
2821         .read    = seq_read,
2822         .llseek  = seq_lseek,
2823         .release = seq_release,
2824 };
2825 
2826 #endif /* CONFIG_PROC_FS */
2827 
2828 static inline size_t neigh_nlmsg_size(void)
2829 {
2830         return NLMSG_ALIGN(sizeof(struct ndmsg))
2831                + nla_total_size(MAX_ADDR_LEN) /* NDA_DST */
2832                + nla_total_size(MAX_ADDR_LEN) /* NDA_LLADDR */
2833                + nla_total_size(sizeof(struct nda_cacheinfo))
2834                + nla_total_size(4); /* NDA_PROBES */
2835 }
2836 
2837 static void __neigh_notify(struct neighbour *n, int type, int flags)
2838 {
2839         struct net *net = dev_net(n->dev);
2840         struct sk_buff *skb;
2841         int err = -ENOBUFS;
2842 
2843         skb = nlmsg_new(neigh_nlmsg_size(), GFP_ATOMIC);
2844         if (skb == NULL)
2845                 goto errout;
2846 
2847         err = neigh_fill_info(skb, n, 0, 0, type, flags);
2848         if (err < 0) {
2849                 /* -EMSGSIZE implies BUG in neigh_nlmsg_size() */
2850                 WARN_ON(err == -EMSGSIZE);
2851                 kfree_skb(skb);
2852                 goto errout;
2853         }
2854         rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
2855         return;
2856 errout:
2857         if (err < 0)
2858                 rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
2859 }
2860 
2861 void neigh_app_ns(struct neighbour *n)
2862 {
2863         __neigh_notify(n, RTM_GETNEIGH, NLM_F_REQUEST);
2864 }
2865 EXPORT_SYMBOL(neigh_app_ns);
2866 
2867 #ifdef CONFIG_SYSCTL
2868 static int zero;
2869 static int int_max = INT_MAX;
2870 static int unres_qlen_max = INT_MAX / SKB_TRUESIZE(ETH_FRAME_LEN);
2871 
2872 static int proc_unres_qlen(struct ctl_table *ctl, int write,
2873                            void __user *buffer, size_t *lenp, loff_t *ppos)
2874 {
2875         int size, ret;
2876         struct ctl_table tmp = *ctl;
2877 
2878         tmp.extra1 = &zero;
2879         tmp.extra2 = &unres_qlen_max;
2880         tmp.data = &size;
2881 
2882         size = *(int *)ctl->data / SKB_TRUESIZE(ETH_FRAME_LEN);
2883         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
2884 
2885         if (write && !ret)
2886                 *(int *)ctl->data = size * SKB_TRUESIZE(ETH_FRAME_LEN);
2887         return ret;
2888 }
2889 
2890 static struct neigh_parms *neigh_get_dev_parms_rcu(struct net_device *dev,
2891                                                    int family)
2892 {
2893         switch (family) {
2894         case AF_INET:
2895                 return __in_dev_arp_parms_get_rcu(dev);
2896         case AF_INET6:
2897                 return __in6_dev_nd_parms_get_rcu(dev);
2898         }
2899         return NULL;
2900 }
2901 
2902 static void neigh_copy_dflt_parms(struct net *net, struct neigh_parms *p,
2903                                   int index)
2904 {
2905         struct net_device *dev;
2906         int family = neigh_parms_family(p);
2907 
2908         rcu_read_lock();
2909         for_each_netdev_rcu(net, dev) {
2910                 struct neigh_parms *dst_p =
2911                                 neigh_get_dev_parms_rcu(dev, family);
2912 
2913                 if (dst_p && !test_bit(index, dst_p->data_state))
2914                         dst_p->data[index] = p->data[index];
2915         }
2916         rcu_read_unlock();
2917 }
2918 
2919 static void neigh_proc_update(struct ctl_table *ctl, int write)
2920 {
2921         struct net_device *dev = ctl->extra1;
2922         struct neigh_parms *p = ctl->extra2;
2923         struct net *net = neigh_parms_net(p);
2924         int index = (int *) ctl->data - p->data;
2925 
2926         if (!write)
2927                 return;
2928 
2929         set_bit(index, p->data_state);
2930         call_netevent_notifiers(NETEVENT_DELAY_PROBE_TIME_UPDATE, p);
2931         if (!dev) /* NULL dev means this is default value */
2932                 neigh_copy_dflt_parms(net, p, index);
2933 }
2934 
2935 static int neigh_proc_dointvec_zero_intmax(struct ctl_table *ctl, int write,
2936                                            void __user *buffer,
2937                                            size_t *lenp, loff_t *ppos)
2938 {
2939         struct ctl_table tmp = *ctl;
2940         int ret;
2941 
2942         tmp.extra1 = &zero;
2943         tmp.extra2 = &int_max;
2944 
2945         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
2946         neigh_proc_update(ctl, write);
2947         return ret;
2948 }
2949 
2950 int neigh_proc_dointvec(struct ctl_table *ctl, int write,
2951                         void __user *buffer, size_t *lenp, loff_t *ppos)
2952 {
2953         int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
2954 
2955         neigh_proc_update(ctl, write);
2956         return ret;
2957 }
2958 EXPORT_SYMBOL(neigh_proc_dointvec);
2959 
2960 int neigh_proc_dointvec_jiffies(struct ctl_table *ctl, int write,
2961                                 void __user *buffer,
2962                                 size_t *lenp, loff_t *ppos)
2963 {
2964         int ret = proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
2965 
2966         neigh_proc_update(ctl, write);
2967         return ret;
2968 }
2969 EXPORT_SYMBOL(neigh_proc_dointvec_jiffies);
2970 
2971 static int neigh_proc_dointvec_userhz_jiffies(struct ctl_table *ctl, int write,
2972                                               void __user *buffer,
2973                                               size_t *lenp, loff_t *ppos)
2974 {
2975         int ret = proc_dointvec_userhz_jiffies(ctl, write, buffer, lenp, ppos);
2976 
2977         neigh_proc_update(ctl, write);
2978         return ret;
2979 }
2980 
2981 int neigh_proc_dointvec_ms_jiffies(struct ctl_table *ctl, int write,
2982                                    void __user *buffer,
2983                                    size_t *lenp, loff_t *ppos)
2984 {
2985         int ret = proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
2986 
2987         neigh_proc_update(ctl, write);
2988         return ret;
2989 }
2990 EXPORT_SYMBOL(neigh_proc_dointvec_ms_jiffies);
2991 
2992 static int neigh_proc_dointvec_unres_qlen(struct ctl_table *ctl, int write,
2993                                           void __user *buffer,
2994                                           size_t *lenp, loff_t *ppos)
2995 {
2996         int ret = proc_unres_qlen(ctl, write, buffer, lenp, ppos);
2997 
2998         neigh_proc_update(ctl, write);
2999         return ret;
3000 }
3001 
3002 static int neigh_proc_base_reachable_time(struct ctl_table *ctl, int write,
3003                                           void __user *buffer,
3004                                           size_t *lenp, loff_t *ppos)
3005 {
3006         struct neigh_parms *p = ctl->extra2;
3007         int ret;
3008 
3009         if (strcmp(ctl->procname, "base_reachable_time") == 0)
3010                 ret = neigh_proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);
3011         else if (strcmp(ctl->procname, "base_reachable_time_ms") == 0)
3012                 ret = neigh_proc_dointvec_ms_jiffies(ctl, write, buffer, lenp, ppos);
3013         else
3014                 ret = -1;
3015 
3016         if (write && ret == 0) {
3017                 /* update reachable_time as well, otherwise, the change will
3018                  * only be effective after the next time neigh_periodic_work
3019                  * decides to recompute it
3020                  */
3021                 p->reachable_time =
3022                         neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
3023         }
3024         return ret;
3025 }
3026 
3027 #define NEIGH_PARMS_DATA_OFFSET(index)  \
3028         (&((struct neigh_parms *) 0)->data[index])
3029 
3030 #define NEIGH_SYSCTL_ENTRY(attr, data_attr, name, mval, proc) \
3031         [NEIGH_VAR_ ## attr] = { \
3032                 .procname       = name, \
3033                 .data           = NEIGH_PARMS_DATA_OFFSET(NEIGH_VAR_ ## data_attr), \
3034                 .maxlen         = sizeof(int), \
3035                 .mode           = mval, \
3036                 .proc_handler   = proc, \
3037         }
3038 
3039 #define NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(attr, name) \
3040         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_zero_intmax)
3041 
3042 #define NEIGH_SYSCTL_JIFFIES_ENTRY(attr, name) \
3043         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_jiffies)
3044 
3045 #define NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(attr, name) \
3046         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_userhz_jiffies)
3047 
3048 #define NEIGH_SYSCTL_MS_JIFFIES_ENTRY(attr, name) \
3049         NEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_ms_jiffies)
3050 
3051 #define NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(attr, data_attr, name) \
3052         NEIGH_SYSCTL_ENTRY(attr, data_attr, name, 0644, neigh_proc_dointvec_ms_jiffies)
3053 
3054 #define NEIGH_SYSCTL_UNRES_QLEN_REUSED_ENTRY(attr, data_attr, name) \
3055         NEIGH_SYSCTL_ENTRY(attr, data_attr, name, 0644, neigh_proc_dointvec_unres_qlen)
3056 
3057 static struct neigh_sysctl_table {
3058         struct ctl_table_header *sysctl_header;
3059         struct ctl_table neigh_vars[NEIGH_VAR_MAX + 1];
3060 } neigh_sysctl_template __read_mostly = {
3061         .neigh_vars = {
3062                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(MCAST_PROBES, "mcast_solicit"),
3063                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(UCAST_PROBES, "ucast_solicit"),
3064                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(APP_PROBES, "app_solicit"),
3065                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(MCAST_REPROBES, "mcast_resolicit"),
3066                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(RETRANS_TIME, "retrans_time"),
3067                 NEIGH_SYSCTL_JIFFIES_ENTRY(BASE_REACHABLE_TIME, "base_reachable_time"),
3068                 NEIGH_SYSCTL_JIFFIES_ENTRY(DELAY_PROBE_TIME, "delay_first_probe_time"),
3069                 NEIGH_SYSCTL_JIFFIES_ENTRY(GC_STALETIME, "gc_stale_time"),
3070                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(QUEUE_LEN_BYTES, "unres_qlen_bytes"),
3071                 NEIGH_SYSCTL_ZERO_INTMAX_ENTRY(PROXY_QLEN, "proxy_qlen"),
3072                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(ANYCAST_DELAY, "anycast_delay"),
3073                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(PROXY_DELAY, "proxy_delay"),
3074                 NEIGH_SYSCTL_USERHZ_JIFFIES_ENTRY(LOCKTIME, "locktime"),
3075                 NEIGH_SYSCTL_UNRES_QLEN_REUSED_ENTRY(QUEUE_LEN, QUEUE_LEN_BYTES, "unres_qlen"),
3076                 NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(RETRANS_TIME_MS, RETRANS_TIME, "retrans_time_ms"),
3077                 NEIGH_SYSCTL_MS_JIFFIES_REUSED_ENTRY(BASE_REACHABLE_TIME_MS, BASE_REACHABLE_TIME, "base_reachable_time_ms"),
3078                 [NEIGH_VAR_GC_INTERVAL] = {
3079                         .procname       = "gc_interval",
3080                         .maxlen         = sizeof(int),
3081                         .mode           = 0644,
3082                         .proc_handler   = proc_dointvec_jiffies,
3083                 },
3084                 [NEIGH_VAR_GC_THRESH1] = {
3085                         .procname       = "gc_thresh1",
3086                         .maxlen         = sizeof(int),
3087                         .mode           = 0644,
3088                         .extra1         = &zero,
3089                         .extra2         = &int_max,
3090                         .proc_handler   = proc_dointvec_minmax,
3091                 },
3092                 [NEIGH_VAR_GC_THRESH2] = {
3093                         .procname       = "gc_thresh2",
3094                         .maxlen         = sizeof(int),
3095                         .mode           = 0644,
3096                         .extra1         = &zero,
3097                         .extra2         = &int_max,
3098                         .proc_handler   = proc_dointvec_minmax,
3099                 },
3100                 [NEIGH_VAR_GC_THRESH3] = {
3101                         .procname       = "gc_thresh3",
3102                         .maxlen         = sizeof(int),
3103                         .mode           = 0644,
3104                         .extra1         = &zero,
3105                         .extra2         = &int_max,
3106                         .proc_handler   = proc_dointvec_minmax,
3107                 },
3108                 {},
3109         },
3110 };
3111 
3112 int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
3113                           proc_handler *handler)
3114 {
3115         int i;
3116         struct neigh_sysctl_table *t;
3117         const char *dev_name_source;
3118         char neigh_path[ sizeof("net//neigh/") + IFNAMSIZ + IFNAMSIZ ];
3119         char *p_name;
3120 
3121         t = kmemdup(&neigh_sysctl_template, sizeof(*t), GFP_KERNEL);
3122         if (!t)
3123                 goto err;
3124 
3125         for (i = 0; i < NEIGH_VAR_GC_INTERVAL; i++) {
3126                 t->neigh_vars[i].data += (long) p;
3127                 t->neigh_vars[i].extra1 = dev;
3128                 t->neigh_vars[i].extra2 = p;
3129         }
3130 
3131         if (dev) {
3132                 dev_name_source = dev->name;
3133                 /* Terminate the table early */
3134                 memset(&t->neigh_vars[NEIGH_VAR_GC_INTERVAL], 0,
3135                        sizeof(t->neigh_vars[NEIGH_VAR_GC_INTERVAL]));
3136         } else {
3137                 struct neigh_table *tbl = p->tbl;
3138                 dev_name_source = "default";
3139                 t->neigh_vars[NEIGH_VAR_GC_INTERVAL].data = &tbl->gc_interval;
3140                 t->neigh_vars[NEIGH_VAR_GC_THRESH1].data = &tbl->gc_thresh1;
3141                 t->neigh_vars[NEIGH_VAR_GC_THRESH2].data = &tbl->gc_thresh2;
3142                 t->neigh_vars[NEIGH_VAR_GC_THRESH3].data = &tbl->gc_thresh3;
3143         }
3144 
3145         if (handler) {
3146                 /* RetransTime */
3147                 t->neigh_vars[NEIGH_VAR_RETRANS_TIME].proc_handler = handler;
3148                 /* ReachableTime */
3149                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME].proc_handler = handler;
3150                 /* RetransTime (in milliseconds)*/
3151                 t->neigh_vars[NEIGH_VAR_RETRANS_TIME_MS].proc_handler = handler;
3152                 /* ReachableTime (in milliseconds) */
3153                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME_MS].proc_handler = handler;
3154         } else {
3155                 /* Those handlers will update p->reachable_time after
3156                  * base_reachable_time(_ms) is set to ensure the new timer starts being
3157                  * applied after the next neighbour update instead of waiting for
3158                  * neigh_periodic_work to update its value (can be multiple minutes)
3159                  * So any handler that replaces them should do this as well
3160                  */
3161                 /* ReachableTime */
3162                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME].proc_handler =
3163                         neigh_proc_base_reachable_time;
3164                 /* ReachableTime (in milliseconds) */
3165                 t->neigh_vars[NEIGH_VAR_BASE_REACHABLE_TIME_MS].proc_handler =
3166                         neigh_proc_base_reachable_time;
3167         }
3168 
3169         /* Don't export sysctls to unprivileged users */
3170         if (neigh_parms_net(p)->user_ns != &init_user_ns)
3171                 t->neigh_vars[0].procname = NULL;
3172 
3173         switch (neigh_parms_family(p)) {
3174         case AF_INET:
3175               p_name = "ipv4";
3176               break;
3177         case AF_INET6:
3178               p_name = "ipv6";
3179               break;
3180         default:
3181               BUG();
3182         }
3183 
3184         snprintf(neigh_path, sizeof(neigh_path), "net/%s/neigh/%s",
3185                 p_name, dev_name_source);
3186         t->sysctl_header =
3187                 register_net_sysctl(neigh_parms_net(p), neigh_path, t->neigh_vars);
3188         if (!t->sysctl_header)
3189                 goto free;
3190 
3191         p->sysctl_table = t;
3192         return 0;
3193 
3194 free:
3195         kfree(t);
3196 err:
3197         return -ENOBUFS;
3198 }
3199 EXPORT_SYMBOL(neigh_sysctl_register);
3200 
3201 void neigh_sysctl_unregister(struct neigh_parms *p)
3202 {
3203         if (p->sysctl_table) {
3204                 struct neigh_sysctl_table *t = p->sysctl_table;
3205                 p->sysctl_table = NULL;
3206                 unregister_net_sysctl_table(t->sysctl_header);
3207                 kfree(t);
3208         }
3209 }
3210 EXPORT_SYMBOL(neigh_sysctl_unregister);
3211 
3212 #endif  /* CONFIG_SYSCTL */
3213 
3214 static int __init neigh_init(void)
3215 {
3216         rtnl_register(PF_UNSPEC, RTM_NEWNEIGH, neigh_add, NULL, NULL);
3217         rtnl_register(PF_UNSPEC, RTM_DELNEIGH, neigh_delete, NULL, NULL);
3218         rtnl_register(PF_UNSPEC, RTM_GETNEIGH, NULL, neigh_dump_info, NULL);
3219 
3220         rtnl_register(PF_UNSPEC, RTM_GETNEIGHTBL, NULL, neightbl_dump_info,
3221                       NULL);
3222         rtnl_register(PF_UNSPEC, RTM_SETNEIGHTBL, neightbl_set, NULL, NULL);
3223 
3224         return 0;
3225 }
3226 
3227 subsys_initcall(neigh_init);
3228 
3229 

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