summaryrefslogtreecommitdiff
path: root/net/bridge/br_fdb.c
blob: e0670d7054f97c05d46b74952ee53d6fa6910776 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
/*
 *	Forwarding database
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<buytenh@gnu.org>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <linux/spinlock.h>
#include <linux/times.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/jhash.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <asm/unaligned.h>
#include <linux/if_vlan.h>
#include "br_private.h"

static struct kmem_cache *br_fdb_cache __read_mostly;
static struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
					     const unsigned char *addr,
					     __u16 vid);
static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
		      const unsigned char *addr, u16 vid);
static void fdb_notify(struct net_bridge *br,
		       const struct net_bridge_fdb_entry *, int);

static u32 fdb_salt __read_mostly;

int __init br_fdb_init(void)
{
	br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
					 sizeof(struct net_bridge_fdb_entry),
					 0,
					 SLAB_HWCACHE_ALIGN, NULL);
	if (!br_fdb_cache)
		return -ENOMEM;

	get_random_bytes(&fdb_salt, sizeof(fdb_salt));
	return 0;
}

void br_fdb_fini(void)
{
	kmem_cache_destroy(br_fdb_cache);
}


/* if topology_changing then use forward_delay (default 15 sec)
 * otherwise keep longer (default 5 minutes)
 */
static inline unsigned long hold_time(const struct net_bridge *br)
{
	return br->topology_change ? br->forward_delay : br->ageing_time;
}

static inline int has_expired(const struct net_bridge *br,
				  const struct net_bridge_fdb_entry *fdb)
{
	return !fdb->is_static &&
		time_before_eq(fdb->updated + hold_time(br), jiffies);
}

static inline int br_mac_hash(const unsigned char *mac, __u16 vid)
{
	/* use 1 byte of OUI and 3 bytes of NIC */
	u32 key = get_unaligned((u32 *)(mac + 2));
	return jhash_2words(key, vid, fdb_salt) & (BR_HASH_SIZE - 1);
}

static void fdb_rcu_free(struct rcu_head *head)
{
	struct net_bridge_fdb_entry *ent
		= container_of(head, struct net_bridge_fdb_entry, rcu);
	kmem_cache_free(br_fdb_cache, ent);
}

/* When a static FDB entry is added, the mac address from the entry is
 * added to the bridge private HW address list and all required ports
 * are then updated with the new information.
 * Called under RTNL.
 */
static void fdb_add_hw_addr(struct net_bridge *br, const unsigned char *addr)
{
	int err;
	struct net_bridge_port *p;

	ASSERT_RTNL();

	list_for_each_entry(p, &br->port_list, list) {
		if (!br_promisc_port(p)) {
			err = dev_uc_add(p->dev, addr);
			if (err)
				goto undo;
		}
	}

	return;
undo:
	list_for_each_entry_continue_reverse(p, &br->port_list, list) {
		if (!br_promisc_port(p))
			dev_uc_del(p->dev, addr);
	}
}

/* When a static FDB entry is deleted, the HW address from that entry is
 * also removed from the bridge private HW address list and updates all
 * the ports with needed information.
 * Called under RTNL.
 */
static void fdb_del_hw_addr(struct net_bridge *br, const unsigned char *addr)
{
	struct net_bridge_port *p;

	ASSERT_RTNL();

	list_for_each_entry(p, &br->port_list, list) {
		if (!br_promisc_port(p))
			dev_uc_del(p->dev, addr);
	}
}

static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f)
{
	if (f->is_static)
		fdb_del_hw_addr(br, f->addr.addr);

	hlist_del_rcu(&f->hlist);
	fdb_notify(br, f, RTM_DELNEIGH);
	call_rcu(&f->rcu, fdb_rcu_free);
}

/* Delete a local entry if no other port had the same address. */
static void fdb_delete_local(struct net_bridge *br,
			     const struct net_bridge_port *p,
			     struct net_bridge_fdb_entry *f)
{
	const unsigned char *addr = f->addr.addr;
	u16 vid = f->vlan_id;
	struct net_bridge_port *op;

	/* Maybe another port has same hw addr? */
	list_for_each_entry(op, &br->port_list, list) {
		if (op != p && ether_addr_equal(op->dev->dev_addr, addr) &&
		    (!vid || nbp_vlan_find(op, vid))) {
			f->dst = op;
			f->added_by_user = 0;
			return;
		}
	}

	/* Maybe bridge device has same hw addr? */
	if (p && ether_addr_equal(br->dev->dev_addr, addr) &&
	    (!vid || br_vlan_find(br, vid))) {
		f->dst = NULL;
		f->added_by_user = 0;
		return;
	}

	fdb_delete(br, f);
}

void br_fdb_find_delete_local(struct net_bridge *br,
			      const struct net_bridge_port *p,
			      const unsigned char *addr, u16 vid)
{
	struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
	struct net_bridge_fdb_entry *f;

	spin_lock_bh(&br->hash_lock);
	f = fdb_find(head, addr, vid);
	if (f && f->is_local && !f->added_by_user && f->dst == p)
		fdb_delete_local(br, p, f);
	spin_unlock_bh(&br->hash_lock);
}

void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
{
	struct net_bridge *br = p->br;
	struct net_port_vlans *pv = nbp_get_vlan_info(p);
	bool no_vlan = !pv;
	int i;
	u16 vid;

	spin_lock_bh(&br->hash_lock);

	/* Search all chains since old address/hash is unknown */
	for (i = 0; i < BR_HASH_SIZE; i++) {
		struct hlist_node *h;
		hlist_for_each(h, &br->hash[i]) {
			struct net_bridge_fdb_entry *f;

			f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
			if (f->dst == p && f->is_local && !f->added_by_user) {
				/* delete old one */
				fdb_delete_local(br, p, f);

				/* if this port has no vlan information
				 * configured, we can safely be done at
				 * this point.
				 */
				if (no_vlan)
					goto insert;
			}
		}
	}

insert:
	/* insert new address,  may fail if invalid address or dup. */
	fdb_insert(br, p, newaddr, 0);

	if (no_vlan)
		goto done;

	/* Now add entries for every VLAN configured on the port.
	 * This function runs under RTNL so the bitmap will not change
	 * from under us.
	 */
	for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID)
		fdb_insert(br, p, newaddr, vid);

done:
	spin_unlock_bh(&br->hash_lock);
}

void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr)
{
	struct net_bridge_fdb_entry *f;
	struct net_port_vlans *pv;
	u16 vid = 0;

	spin_lock_bh(&br->hash_lock);

	/* If old entry was unassociated with any port, then delete it. */
	f = __br_fdb_get(br, br->dev->dev_addr, 0);
	if (f && f->is_local && !f->dst)
		fdb_delete_local(br, NULL, f);

	fdb_insert(br, NULL, newaddr, 0);

	/* Now remove and add entries for every VLAN configured on the
	 * bridge.  This function runs under RTNL so the bitmap will not
	 * change from under us.
	 */
	pv = br_get_vlan_info(br);
	if (!pv)
		goto out;

	for_each_set_bit_from(vid, pv->vlan_bitmap, VLAN_N_VID) {
		f = __br_fdb_get(br, br->dev->dev_addr, vid);
		if (f && f->is_local && !f->dst)
			fdb_delete_local(br, NULL, f);
		fdb_insert(br, NULL, newaddr, vid);
	}
out:
	spin_unlock_bh(&br->hash_lock);
}

void br_fdb_cleanup(unsigned long _data)
{
	struct net_bridge *br = (struct net_bridge *)_data;
	unsigned long delay = hold_time(br);
	unsigned long next_timer = jiffies + br->ageing_time;
	int i;

	spin_lock(&br->hash_lock);
	for (i = 0; i < BR_HASH_SIZE; i++) {
		struct net_bridge_fdb_entry *f;
		struct hlist_node *n;

		hlist_for_each_entry_safe(f, n, &br->hash[i], hlist) {
			unsigned long this_timer;
			if (f->is_static)
				continue;
			this_timer = f->updated + delay;
			if (time_before_eq(this_timer, jiffies))
				fdb_delete(br, f);
			else if (time_before(this_timer, next_timer))
				next_timer = this_timer;
		}
	}
	spin_unlock(&br->hash_lock);

	mod_timer(&br->gc_timer, round_jiffies_up(next_timer));
}

/* Completely flush all dynamic entries in forwarding database.*/
void br_fdb_flush(struct net_bridge *br)
{
	int i;

	spin_lock_bh(&br->hash_lock);
	for (i = 0; i < BR_HASH_SIZE; i++) {
		struct net_bridge_fdb_entry *f;
		struct hlist_node *n;
		hlist_for_each_entry_safe(f, n, &br->hash[i], hlist) {
			if (!f->is_static)
				fdb_delete(br, f);
		}
	}
	spin_unlock_bh(&br->hash_lock);
}

/* Flush all entries referring to a specific port.
 * if do_all is set also flush static entries
 */
void br_fdb_delete_by_port(struct net_bridge *br,
			   const struct net_bridge_port *p,
			   int do_all)
{
	int i;

	spin_lock_bh(&br->hash_lock);
	for (i = 0; i < BR_HASH_SIZE; i++) {
		struct hlist_node *h, *g;

		hlist_for_each_safe(h, g, &br->hash[i]) {
			struct net_bridge_fdb_entry *f
				= hlist_entry(h, struct net_bridge_fdb_entry, hlist);
			if (f->dst != p)
				continue;

			if (f->is_static && !do_all)
				continue;

			if (f->is_local)
				fdb_delete_local(br, p, f);
			else
				fdb_delete(br, f);
		}
	}
	spin_unlock_bh(&br->hash_lock);
}

/* No locking or refcounting, assumes caller has rcu_read_lock */
struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
					  const unsigned char *addr,
					  __u16 vid)
{
	struct net_bridge_fdb_entry *fdb;

	hlist_for_each_entry_rcu(fdb,
				&br->hash[br_mac_hash(addr, vid)], hlist) {
		if (ether_addr_equal(fdb->addr.addr, addr) &&
		    fdb->vlan_id == vid) {
			if (unlikely(has_expired(br, fdb)))
				break;
			return fdb;
		}
	}

	return NULL;
}

#if IS_ENABLED(CONFIG_ATM_LANE)
/* Interface used by ATM LANE hook to test
 * if an addr is on some other bridge port */
int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
{
	struct net_bridge_fdb_entry *fdb;
	struct net_bridge_port *port;
	int ret;

	rcu_read_lock();
	port = br_port_get_rcu(dev);
	if (!port)
		ret = 0;
	else {
		fdb = __br_fdb_get(port->br, addr, 0);
		ret = fdb && fdb->dst && fdb->dst->dev != dev &&
			fdb->dst->state == BR_STATE_FORWARDING;
	}
	rcu_read_unlock();

	return ret;
}
#endif /* CONFIG_ATM_LANE */

/*
 * Fill buffer with forwarding table records in
 * the API format.
 */
int br_fdb_fillbuf(struct net_bridge *br, void *buf,
		   unsigned long maxnum, unsigned long skip)
{
	struct __fdb_entry *fe = buf;
	int i, num = 0;
	struct net_bridge_fdb_entry *f;

	memset(buf, 0, maxnum*sizeof(struct __fdb_entry));

	rcu_read_lock();
	for (i = 0; i < BR_HASH_SIZE; i++) {
		hlist_for_each_entry_rcu(f, &br->hash[i], hlist) {
			if (num >= maxnum)
				goto out;

			if (has_expired(br, f))
				continue;

			/* ignore pseudo entry for local MAC address */
			if (!f->dst)
				continue;

			if (skip) {
				--skip;
				continue;
			}

			/* convert from internal format to API */
			memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);

			/* due to ABI compat need to split into hi/lo */
			fe->port_no = f->dst->port_no;
			fe->port_hi = f->dst->port_no >> 8;

			fe->is_local = f->is_local;
			if (!f->is_static)
				fe->ageing_timer_value = jiffies_delta_to_clock_t(jiffies - f->updated);
			++fe;
			++num;
		}
	}

 out:
	rcu_read_unlock();

	return num;
}

static struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
					     const unsigned char *addr,
					     __u16 vid)
{
	struct net_bridge_fdb_entry *fdb;

	hlist_for_each_entry(fdb, head, hlist) {
		if (ether_addr_equal(fdb->addr.addr, addr) &&
		    fdb->vlan_id == vid)
			return fdb;
	}
	return NULL;
}

static struct net_bridge_fdb_entry *fdb_find_rcu(struct hlist_head *head,
						 const unsigned char *addr,
						 __u16 vid)
{
	struct net_bridge_fdb_entry *fdb;

	hlist_for_each_entry_rcu(fdb, head, hlist) {
		if (ether_addr_equal(fdb->addr.addr, addr) &&
		    fdb->vlan_id == vid)
			return fdb;
	}
	return NULL;
}

static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
					       struct net_bridge_port *source,
					       const unsigned char *addr,
					       __u16 vid)
{
	struct net_bridge_fdb_entry *fdb;

	fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
	if (fdb) {
		memcpy(fdb->addr.addr, addr, ETH_ALEN);
		fdb->dst = source;
		fdb->vlan_id = vid;
		fdb->is_local = 0;
		fdb->is_static = 0;
		fdb->added_by_user = 0;
		fdb->added_by_external_learn = 0;
		fdb->updated = fdb->used = jiffies;
		hlist_add_head_rcu(&fdb->hlist, head);
	}
	return fdb;
}

static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
		  const unsigned char *addr, u16 vid)
{
	struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
	struct net_bridge_fdb_entry *fdb;

	if (!is_valid_ether_addr(addr))
		return -EINVAL;

	fdb = fdb_find(head, addr, vid);
	if (fdb) {
		/* it is okay to have multiple ports with same
		 * address, just use the first one.
		 */
		if (fdb->is_local)
			return 0;
		br_warn(br, "adding interface %s with same address "
		       "as a received packet\n",
		       source ? source->dev->name : br->dev->name);
		fdb_delete(br, fdb);
	}

	fdb = fdb_create(head, source, addr, vid);
	if (!fdb)
		return -ENOMEM;

	fdb->is_local = fdb->is_static = 1;
	fdb_add_hw_addr(br, addr);
	fdb_notify(br, fdb, RTM_NEWNEIGH);
	return 0;
}

/* Add entry for local address of interface */
int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
		  const unsigned char *addr, u16 vid)
{
	int ret;

	spin_lock_bh(&br->hash_lock);
	ret = fdb_insert(br, source, addr, vid);
	spin_unlock_bh(&br->hash_lock);
	return ret;
}

void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
		   const unsigned char *addr, u16 vid, bool added_by_user)
{
	struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
	struct net_bridge_fdb_entry *fdb;
	bool fdb_modified = false;

	/* some users want to always flood. */
	if (hold_time(br) == 0)
		return;

	/* ignore packets unless we are using this port */
	if (!(source->state == BR_STATE_LEARNING ||
	      source->state == BR_STATE_FORWARDING))
		return;

	fdb = fdb_find_rcu(head, addr, vid);
	if (likely(fdb)) {
		/* attempt to update an entry for a local interface */
		if (unlikely(fdb->is_local)) {
			if (net_ratelimit())
				br_warn(br, "received packet on %s with "
					"own address as source address\n",
					source->dev->name);
		} else {
			/* fastpath: update of existing entry */
			if (unlikely(source != fdb->dst)) {
				fdb->dst = source;
				fdb_modified = true;
			}
			fdb->updated = jiffies;
			if (unlikely(added_by_user))
				fdb->added_by_user = 1;
			if (unlikely(fdb_modified))
				fdb_notify(br, fdb, RTM_NEWNEIGH);
		}
	} else {
		spin_lock(&br->hash_lock);
		if (likely(!fdb_find(head, addr, vid))) {
			fdb = fdb_create(head, source, addr, vid);
			if (fdb) {
				if (unlikely(added_by_user))
					fdb->added_by_user = 1;
				fdb_notify(br, fdb, RTM_NEWNEIGH);
			}
		}
		/* else  we lose race and someone else inserts
		 * it first, don't bother updating
		 */
		spin_unlock(&br->hash_lock);
	}
}

static int fdb_to_nud(const struct net_bridge_fdb_entry *fdb)
{
	if (fdb->is_local)
		return NUD_PERMANENT;
	else if (fdb->is_static)
		return NUD_NOARP;
	else if (has_expired(fdb->dst->br, fdb))
		return NUD_STALE;
	else
		return NUD_REACHABLE;
}

static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
			 const struct net_bridge_fdb_entry *fdb,
			 u32 portid, u32 seq, int type, unsigned int flags)
{
	unsigned long now = jiffies;
	struct nda_cacheinfo ci;
	struct nlmsghdr *nlh;
	struct ndmsg *ndm;

	nlh = nlmsg_put(skb, portid, seq, type, sizeof(*ndm), flags);
	if (nlh == NULL)
		return -EMSGSIZE;

	ndm = nlmsg_data(nlh);
	ndm->ndm_family	 = AF_BRIDGE;
	ndm->ndm_pad1    = 0;
	ndm->ndm_pad2    = 0;
	ndm->ndm_flags	 = fdb->added_by_external_learn ? NTF_EXT_LEARNED : 0;
	ndm->ndm_type	 = 0;
	ndm->ndm_ifindex = fdb->dst ? fdb->dst->dev->ifindex : br->dev->ifindex;
	ndm->ndm_state   = fdb_to_nud(fdb);

	if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->addr))
		goto nla_put_failure;
	if (nla_put_u32(skb, NDA_MASTER, br->dev->ifindex))
		goto nla_put_failure;
	ci.ndm_used	 = jiffies_to_clock_t(now - fdb->used);
	ci.ndm_confirmed = 0;
	ci.ndm_updated	 = jiffies_to_clock_t(now - fdb->updated);
	ci.ndm_refcnt	 = 0;
	if (nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
		goto nla_put_failure;

	if (fdb->vlan_id && nla_put(skb, NDA_VLAN, sizeof(u16), &fdb->vlan_id))
		goto nla_put_failure;

	nlmsg_end(skb, nlh);
	return 0;

nla_put_failure:
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
}

static inline size_t fdb_nlmsg_size(void)
{
	return NLMSG_ALIGN(sizeof(struct ndmsg))
		+ nla_total_size(ETH_ALEN) /* NDA_LLADDR */
		+ nla_total_size(sizeof(u32)) /* NDA_MASTER */
		+ nla_total_size(sizeof(u16)) /* NDA_VLAN */
		+ nla_total_size(sizeof(struct nda_cacheinfo));
}

static void fdb_notify(struct net_bridge *br,
		       const struct net_bridge_fdb_entry *fdb, int type)
{
	struct net *net = dev_net(br->dev);
	struct sk_buff *skb;
	int err = -ENOBUFS;

	skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC);
	if (skb == NULL)
		goto errout;

	err = fdb_fill_info(skb, br, fdb, 0, 0, type, 0);
	if (err < 0) {
		/* -EMSGSIZE implies BUG in fdb_nlmsg_size() */
		WARN_ON(err == -EMSGSIZE);
		kfree_skb(skb);
		goto errout;
	}
	rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
	return;
errout:
	rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
}

/* Dump information about entries, in response to GETNEIGH */
int br_fdb_dump(struct sk_buff *skb,
		struct netlink_callback *cb,
		struct net_device *dev,
		struct net_device *filter_dev,
		int idx)
{
	struct net_bridge *br = netdev_priv(dev);
	int i;

	if (!(dev->priv_flags & IFF_EBRIDGE))
		goto out;

	if (!filter_dev)
		idx = ndo_dflt_fdb_dump(skb, cb, dev, NULL, idx);

	for (i = 0; i < BR_HASH_SIZE; i++) {
		struct net_bridge_fdb_entry *f;

		hlist_for_each_entry_rcu(f, &br->hash[i], hlist) {
			if (idx < cb->args[0])
				goto skip;

			if (filter_dev &&
			    (!f->dst || f->dst->dev != filter_dev)) {
				if (filter_dev != dev)
					goto skip;
				/* !f->dst is a special case for bridge
				 * It means the MAC belongs to the bridge
				 * Therefore need a little more filtering
				 * we only want to dump the !f->dst case
				 */
				if (f->dst)
					goto skip;
			}
			if (!filter_dev && f->dst)
				goto skip;

			if (fdb_fill_info(skb, br, f,
					  NETLINK_CB(cb->skb).portid,
					  cb->nlh->nlmsg_seq,
					  RTM_NEWNEIGH,
					  NLM_F_MULTI) < 0)
				break;
skip:
			++idx;
		}
	}

out:
	return idx;
}

/* Update (create or replace) forwarding database entry */
static int fdb_add_entry(struct net_bridge_port *source, const __u8 *addr,
			 __u16 state, __u16 flags, __u16 vid)
{
	struct net_bridge *br = source->br;
	struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
	struct net_bridge_fdb_entry *fdb;
	bool modified = false;

	fdb = fdb_find(head, addr, vid);
	if (fdb == NULL) {
		if (!(flags & NLM_F_CREATE))
			return -ENOENT;

		fdb = fdb_create(head, source, addr, vid);
		if (!fdb)
			return -ENOMEM;

		modified = true;
	} else {
		if (flags & NLM_F_EXCL)
			return -EEXIST;

		if (fdb->dst != source) {
			fdb->dst = source;
			modified = true;
		}
	}

	if (fdb_to_nud(fdb) != state) {
		if (state & NUD_PERMANENT) {
			fdb->is_local = 1;
			if (!fdb->is_static) {
				fdb->is_static = 1;
				fdb_add_hw_addr(br, addr);
			}
		} else if (state & NUD_NOARP) {
			fdb->is_local = 0;
			if (!fdb->is_static) {
				fdb->is_static = 1;
				fdb_add_hw_addr(br, addr);
			}
		} else {
			fdb->is_local = 0;
			if (fdb->is_static) {
				fdb->is_static = 0;
				fdb_del_hw_addr(br, addr);
			}
		}

		modified = true;
	}
	fdb->added_by_user = 1;

	fdb->used = jiffies;
	if (modified) {
		fdb->updated = jiffies;
		fdb_notify(br, fdb, RTM_NEWNEIGH);
	}

	return 0;
}

static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge_port *p,
	       const unsigned char *addr, u16 nlh_flags, u16 vid)
{
	int err = 0;

	if (ndm->ndm_flags & NTF_USE) {
		rcu_read_lock();
		br_fdb_update(p->br, p, addr, vid, true);
		rcu_read_unlock();
	} else {
		spin_lock_bh(&p->br->hash_lock);
		err = fdb_add_entry(p, addr, ndm->ndm_state,
				    nlh_flags, vid);
		spin_unlock_bh(&p->br->hash_lock);
	}

	return err;
}

/* Add new permanent fdb entry with RTM_NEWNEIGH */
int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
	       struct net_device *dev,
	       const unsigned char *addr, u16 vid, u16 nlh_flags)
{
	struct net_bridge_port *p;
	int err = 0;
	struct net_port_vlans *pv;

	if (!(ndm->ndm_state & (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE))) {
		pr_info("bridge: RTM_NEWNEIGH with invalid state %#x\n", ndm->ndm_state);
		return -EINVAL;
	}

	if (is_zero_ether_addr(addr)) {
		pr_info("bridge: RTM_NEWNEIGH with invalid ether address\n");
		return -EINVAL;
	}

	p = br_port_get_rtnl(dev);
	if (p == NULL) {
		pr_info("bridge: RTM_NEWNEIGH %s not a bridge port\n",
			dev->name);
		return -EINVAL;
	}

	pv = nbp_get_vlan_info(p);
	if (vid) {
		if (!pv || !test_bit(vid, pv->vlan_bitmap)) {
			pr_info("bridge: RTM_NEWNEIGH with unconfigured "
				"vlan %d on port %s\n", vid, dev->name);
			return -EINVAL;
		}

		/* VID was specified, so use it. */
		err = __br_fdb_add(ndm, p, addr, nlh_flags, vid);
	} else {
		err = __br_fdb_add(ndm, p, addr, nlh_flags, 0);
		if (err || !pv)
			goto out;

		/* We have vlans configured on this port and user didn't
		 * specify a VLAN.  To be nice, add/update entry for every
		 * vlan on this port.
		 */
		for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID) {
			err = __br_fdb_add(ndm, p, addr, nlh_flags, vid);
			if (err)
				goto out;
		}
	}

out:
	return err;
}

static int fdb_delete_by_addr(struct net_bridge *br, const u8 *addr, u16 vlan)
{
	struct hlist_head *head = &br->hash[br_mac_hash(addr, vlan)];
	struct net_bridge_fdb_entry *fdb;

	fdb = fdb_find(head, addr, vlan);
	if (!fdb)
		return -ENOENT;

	fdb_delete(br, fdb);
	return 0;
}

static int __br_fdb_delete(struct net_bridge_port *p,
			   const unsigned char *addr, u16 vid)
{
	int err;

	spin_lock_bh(&p->br->hash_lock);
	err = fdb_delete_by_addr(p->br, addr, vid);
	spin_unlock_bh(&p->br->hash_lock);

	return err;
}

/* Remove neighbor entry with RTM_DELNEIGH */
int br_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
		  struct net_device *dev,
		  const unsigned char *addr, u16 vid)
{
	struct net_bridge_port *p;
	int err;
	struct net_port_vlans *pv;

	p = br_port_get_rtnl(dev);
	if (p == NULL) {
		pr_info("bridge: RTM_DELNEIGH %s not a bridge port\n",
			dev->name);
		return -EINVAL;
	}

	pv = nbp_get_vlan_info(p);
	if (vid) {
		if (!pv || !test_bit(vid, pv->vlan_bitmap)) {
			pr_info("bridge: RTM_DELNEIGH with unconfigured "
				"vlan %d on port %s\n", vid, dev->name);
			return -EINVAL;
		}

		err = __br_fdb_delete(p, addr, vid);
	} else {
		err = -ENOENT;
		err &= __br_fdb_delete(p, addr, 0);
		if (!pv)
			goto out;

		/* We have vlans configured on this port and user didn't
		 * specify a VLAN.  To be nice, add/update entry for every
		 * vlan on this port.
		 */
		for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID) {
			err &= __br_fdb_delete(p, addr, vid);
		}
	}
out:
	return err;
}

int br_fdb_sync_static(struct net_bridge *br, struct net_bridge_port *p)
{
	struct net_bridge_fdb_entry *fdb, *tmp;
	int i;
	int err;

	ASSERT_RTNL();

	for (i = 0; i < BR_HASH_SIZE; i++) {
		hlist_for_each_entry(fdb, &br->hash[i], hlist) {
			/* We only care for static entries */
			if (!fdb->is_static)
				continue;

			err = dev_uc_add(p->dev, fdb->addr.addr);
			if (err)
				goto rollback;
		}
	}
	return 0;

rollback:
	for (i = 0; i < BR_HASH_SIZE; i++) {
		hlist_for_each_entry(tmp, &br->hash[i], hlist) {
			/* If we reached the fdb that failed, we can stop */
			if (tmp == fdb)
				break;

			/* We only care for static entries */
			if (!tmp->is_static)
				continue;

			dev_uc_del(p->dev, tmp->addr.addr);
		}
	}
	return err;
}

void br_fdb_unsync_static(struct net_bridge *br, struct net_bridge_port *p)
{
	struct net_bridge_fdb_entry *fdb;
	int i;

	ASSERT_RTNL();

	for (i = 0; i < BR_HASH_SIZE; i++) {
		hlist_for_each_entry_rcu(fdb, &br->hash[i], hlist) {
			/* We only care for static entries */
			if (!fdb->is_static)
				continue;

			dev_uc_del(p->dev, fdb->addr.addr);
		}
	}
}

int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
			      const unsigned char *addr, u16 vid)
{
	struct hlist_head *head;
	struct net_bridge_fdb_entry *fdb;
	int err = 0;

	ASSERT_RTNL();
	spin_lock_bh(&br->hash_lock);

	head = &br->hash[br_mac_hash(addr, vid)];
	fdb = fdb_find(head, addr, vid);
	if (!fdb) {
		fdb = fdb_create(head, p, addr, vid);
		if (!fdb) {
			err = -ENOMEM;
			goto err_unlock;
		}
		fdb->added_by_external_learn = 1;
		fdb_notify(br, fdb, RTM_NEWNEIGH);
	} else if (fdb->added_by_external_learn) {
		/* Refresh entry */
		fdb->updated = fdb->used = jiffies;
	} else if (!fdb->added_by_user) {
		/* Take over SW learned entry */
		fdb->added_by_external_learn = 1;
		fdb->updated = jiffies;
		fdb_notify(br, fdb, RTM_NEWNEIGH);
	}

err_unlock:
	spin_unlock_bh(&br->hash_lock);

	return err;
}

int br_fdb_external_learn_del(struct net_bridge *br, struct net_bridge_port *p,
			      const unsigned char *addr, u16 vid)
{
	struct hlist_head *head;
	struct net_bridge_fdb_entry *fdb;
	int err = 0;

	ASSERT_RTNL();
	spin_lock_bh(&br->hash_lock);

	head = &br->hash[br_mac_hash(addr, vid)];
	fdb = fdb_find(head, addr, vid);
	if (fdb && fdb->added_by_external_learn)
		fdb_delete(br, fdb);
	else
		err = -ENOENT;

	spin_unlock_bh(&br->hash_lock);

	return err;
}