summaryrefslogtreecommitdiffstats
path: root/net/tipc/bcast.c
blob: 3e41704832de6debbe92d0a46e0cbbaa4701e981 (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
/*
 * net/tipc/bcast.c: TIPC broadcast code
 *
 * Copyright (c) 2004-2006, 2014-2015, Ericsson AB
 * Copyright (c) 2004, Intel Corporation.
 * Copyright (c) 2005, 2010-2011, Wind River Systems
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "socket.h"
#include "msg.h"
#include "bcast.h"
#include "name_distr.h"
#include "core.h"

#define	MAX_PKT_DEFAULT_MCAST	1500	/* bcast link max packet size (fixed) */
#define	BCLINK_WIN_DEFAULT	20	/* bcast link window size (default) */

const char tipc_bclink_name[] = "broadcast-link";

static void tipc_nmap_diff(struct tipc_node_map *nm_a,
			   struct tipc_node_map *nm_b,
			   struct tipc_node_map *nm_diff);
static void tipc_nmap_add(struct tipc_node_map *nm_ptr, u32 node);
static void tipc_nmap_remove(struct tipc_node_map *nm_ptr, u32 node);

static void tipc_bclink_lock(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	spin_lock_bh(&tn->bclink->lock);
}

static void tipc_bclink_unlock(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_node *node = NULL;

	if (likely(!tn->bclink->flags)) {
		spin_unlock_bh(&tn->bclink->lock);
		return;
	}

	if (tn->bclink->flags & TIPC_BCLINK_RESET) {
		tn->bclink->flags &= ~TIPC_BCLINK_RESET;
		node = tipc_bclink_retransmit_to(net);
	}
	spin_unlock_bh(&tn->bclink->lock);

	if (node)
		tipc_link_reset_all(node);
}

void tipc_bclink_input(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	tipc_sk_mcast_rcv(net, &tn->bclink->arrvq, &tn->bclink->inputq);
}

uint  tipc_bclink_get_mtu(void)
{
	return MAX_PKT_DEFAULT_MCAST;
}

void tipc_bclink_set_flags(struct net *net, unsigned int flags)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	tn->bclink->flags |= flags;
}

static u32 bcbuf_acks(struct sk_buff *buf)
{
	return (u32)(unsigned long)TIPC_SKB_CB(buf)->handle;
}

static void bcbuf_set_acks(struct sk_buff *buf, u32 acks)
{
	TIPC_SKB_CB(buf)->handle = (void *)(unsigned long)acks;
}

static void bcbuf_decr_acks(struct sk_buff *buf)
{
	bcbuf_set_acks(buf, bcbuf_acks(buf) - 1);
}

void tipc_bclink_add_node(struct net *net, u32 addr)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	tipc_bclink_lock(net);
	tipc_nmap_add(&tn->bclink->bcast_nodes, addr);
	tipc_bclink_unlock(net);
}

void tipc_bclink_remove_node(struct net *net, u32 addr)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	tipc_bclink_lock(net);
	tipc_nmap_remove(&tn->bclink->bcast_nodes, addr);
	tipc_bclink_unlock(net);
}

static void bclink_set_last_sent(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_link *bcl = tn->bcl;

	if (bcl->next_out)
		bcl->fsm_msg_cnt = mod(buf_seqno(bcl->next_out) - 1);
	else
		bcl->fsm_msg_cnt = mod(bcl->next_out_no - 1);
}

u32 tipc_bclink_get_last_sent(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	return tn->bcl->fsm_msg_cnt;
}

static void bclink_update_last_sent(struct tipc_node *node, u32 seqno)
{
	node->bclink.last_sent = less_eq(node->bclink.last_sent, seqno) ?
						seqno : node->bclink.last_sent;
}


/**
 * tipc_bclink_retransmit_to - get most recent node to request retransmission
 *
 * Called with bclink_lock locked
 */
struct tipc_node *tipc_bclink_retransmit_to(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	return tn->bclink->retransmit_to;
}

/**
 * bclink_retransmit_pkt - retransmit broadcast packets
 * @after: sequence number of last packet to *not* retransmit
 * @to: sequence number of last packet to retransmit
 *
 * Called with bclink_lock locked
 */
static void bclink_retransmit_pkt(struct tipc_net *tn, u32 after, u32 to)
{
	struct sk_buff *skb;
	struct tipc_link *bcl = tn->bcl;

	skb_queue_walk(&bcl->outqueue, skb) {
		if (more(buf_seqno(skb), after)) {
			tipc_link_retransmit(bcl, skb, mod(to - after));
			break;
		}
	}
}

/**
 * tipc_bclink_wakeup_users - wake up pending users
 *
 * Called with no locks taken
 */
void tipc_bclink_wakeup_users(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	tipc_sk_rcv(net, &tn->bclink->link.wakeupq);
}

/**
 * tipc_bclink_acknowledge - handle acknowledgement of broadcast packets
 * @n_ptr: node that sent acknowledgement info
 * @acked: broadcast sequence # that has been acknowledged
 *
 * Node is locked, bclink_lock unlocked.
 */
void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
{
	struct sk_buff *skb, *tmp;
	struct sk_buff *next;
	unsigned int released = 0;
	struct net *net = n_ptr->net;
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	tipc_bclink_lock(net);
	/* Bail out if tx queue is empty (no clean up is required) */
	skb = skb_peek(&tn->bcl->outqueue);
	if (!skb)
		goto exit;

	/* Determine which messages need to be acknowledged */
	if (acked == INVALID_LINK_SEQ) {
		/*
		 * Contact with specified node has been lost, so need to
		 * acknowledge sent messages only (if other nodes still exist)
		 * or both sent and unsent messages (otherwise)
		 */
		if (tn->bclink->bcast_nodes.count)
			acked = tn->bcl->fsm_msg_cnt;
		else
			acked = tn->bcl->next_out_no;
	} else {
		/*
		 * Bail out if specified sequence number does not correspond
		 * to a message that has been sent and not yet acknowledged
		 */
		if (less(acked, buf_seqno(skb)) ||
		    less(tn->bcl->fsm_msg_cnt, acked) ||
		    less_eq(acked, n_ptr->bclink.acked))
			goto exit;
	}

	/* Skip over packets that node has previously acknowledged */
	skb_queue_walk(&tn->bcl->outqueue, skb) {
		if (more(buf_seqno(skb), n_ptr->bclink.acked))
			break;
	}

	/* Update packets that node is now acknowledging */
	skb_queue_walk_from_safe(&tn->bcl->outqueue, skb, tmp) {
		if (more(buf_seqno(skb), acked))
			break;

		next = tipc_skb_queue_next(&tn->bcl->outqueue, skb);
		if (skb != tn->bcl->next_out) {
			bcbuf_decr_acks(skb);
		} else {
			bcbuf_set_acks(skb, 0);
			tn->bcl->next_out = next;
			bclink_set_last_sent(net);
		}

		if (bcbuf_acks(skb) == 0) {
			__skb_unlink(skb, &tn->bcl->outqueue);
			kfree_skb(skb);
			released = 1;
		}
	}
	n_ptr->bclink.acked = acked;

	/* Try resolving broadcast link congestion, if necessary */
	if (unlikely(tn->bcl->next_out)) {
		tipc_link_push_packets(tn->bcl);
		bclink_set_last_sent(net);
	}
	if (unlikely(released && !skb_queue_empty(&tn->bcl->wakeupq)))
		n_ptr->action_flags |= TIPC_WAKEUP_BCAST_USERS;
exit:
	tipc_bclink_unlock(net);
}

/**
 * tipc_bclink_update_link_state - update broadcast link state
 *
 * RCU and node lock set
 */
void tipc_bclink_update_link_state(struct tipc_node *n_ptr,
				   u32 last_sent)
{
	struct sk_buff *buf;
	struct net *net = n_ptr->net;
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	/* Ignore "stale" link state info */
	if (less_eq(last_sent, n_ptr->bclink.last_in))
		return;

	/* Update link synchronization state; quit if in sync */
	bclink_update_last_sent(n_ptr, last_sent);

	if (n_ptr->bclink.last_sent == n_ptr->bclink.last_in)
		return;

	/* Update out-of-sync state; quit if loss is still unconfirmed */
	if ((++n_ptr->bclink.oos_state) == 1) {
		if (n_ptr->bclink.deferred_size < (TIPC_MIN_LINK_WIN / 2))
			return;
		n_ptr->bclink.oos_state++;
	}

	/* Don't NACK if one has been recently sent (or seen) */
	if (n_ptr->bclink.oos_state & 0x1)
		return;

	/* Send NACK */
	buf = tipc_buf_acquire(INT_H_SIZE);
	if (buf) {
		struct tipc_msg *msg = buf_msg(buf);
		struct sk_buff *skb = skb_peek(&n_ptr->bclink.deferred_queue);
		u32 to = skb ? buf_seqno(skb) - 1 : n_ptr->bclink.last_sent;

		tipc_msg_init(tn->own_addr, msg, BCAST_PROTOCOL, STATE_MSG,
			      INT_H_SIZE, n_ptr->addr);
		msg_set_non_seq(msg, 1);
		msg_set_mc_netid(msg, tn->net_id);
		msg_set_bcast_ack(msg, n_ptr->bclink.last_in);
		msg_set_bcgap_after(msg, n_ptr->bclink.last_in);
		msg_set_bcgap_to(msg, to);

		tipc_bclink_lock(net);
		tipc_bearer_send(net, MAX_BEARERS, buf, NULL);
		tn->bcl->stats.sent_nacks++;
		tipc_bclink_unlock(net);
		kfree_skb(buf);

		n_ptr->bclink.oos_state++;
	}
}

/**
 * bclink_peek_nack - monitor retransmission requests sent by other nodes
 *
 * Delay any upcoming NACK by this node if another node has already
 * requested the first message this node is going to ask for.
 */
static void bclink_peek_nack(struct net *net, struct tipc_msg *msg)
{
	struct tipc_node *n_ptr = tipc_node_find(net, msg_destnode(msg));

	if (unlikely(!n_ptr))
		return;

	tipc_node_lock(n_ptr);

	if (n_ptr->bclink.recv_permitted &&
	    (n_ptr->bclink.last_in != n_ptr->bclink.last_sent) &&
	    (n_ptr->bclink.last_in == msg_bcgap_after(msg)))
		n_ptr->bclink.oos_state = 2;

	tipc_node_unlock(n_ptr);
}

/* tipc_bclink_xmit - deliver buffer chain to all nodes in cluster
 *                    and to identified node local sockets
 * @net: the applicable net namespace
 * @list: chain of buffers containing message
 * Consumes the buffer chain, except when returning -ELINKCONG
 * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
 */
int tipc_bclink_xmit(struct net *net, struct sk_buff_head *list)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_link *bcl = tn->bcl;
	struct tipc_bclink *bclink = tn->bclink;
	int rc = 0;
	int bc = 0;
	struct sk_buff *skb;
	struct sk_buff_head arrvq;
	struct sk_buff_head inputq;

	/* Prepare clone of message for local node */
	skb = tipc_msg_reassemble(list);
	if (unlikely(!skb)) {
		__skb_queue_purge(list);
		return -EHOSTUNREACH;
	}

	/* Broadcast to all nodes */
	if (likely(bclink)) {
		tipc_bclink_lock(net);
		if (likely(bclink->bcast_nodes.count)) {
			rc = __tipc_link_xmit(net, bcl, list);
			if (likely(!rc)) {
				u32 len = skb_queue_len(&bcl->outqueue);

				bclink_set_last_sent(net);
				bcl->stats.queue_sz_counts++;
				bcl->stats.accu_queue_sz += len;
			}
			bc = 1;
		}
		tipc_bclink_unlock(net);
	}

	if (unlikely(!bc))
		__skb_queue_purge(list);

	if (unlikely(rc)) {
		kfree_skb(skb);
		return rc;
	}
	/* Deliver message clone */
	__skb_queue_head_init(&arrvq);
	skb_queue_head_init(&inputq);
	__skb_queue_tail(&arrvq, skb);
	tipc_sk_mcast_rcv(net, &arrvq, &inputq);
	return rc;
}

/**
 * bclink_accept_pkt - accept an incoming, in-sequence broadcast packet
 *
 * Called with both sending node's lock and bclink_lock taken.
 */
static void bclink_accept_pkt(struct tipc_node *node, u32 seqno)
{
	struct tipc_net *tn = net_generic(node->net, tipc_net_id);

	bclink_update_last_sent(node, seqno);
	node->bclink.last_in = seqno;
	node->bclink.oos_state = 0;
	tn->bcl->stats.recv_info++;

	/*
	 * Unicast an ACK periodically, ensuring that
	 * all nodes in the cluster don't ACK at the same time
	 */
	if (((seqno - tn->own_addr) % TIPC_MIN_LINK_WIN) == 0) {
		tipc_link_proto_xmit(node->active_links[node->addr & 1],
				     STATE_MSG, 0, 0, 0, 0, 0);
		tn->bcl->stats.sent_acks++;
	}
}

/**
 * tipc_bclink_rcv - receive a broadcast packet, and deliver upwards
 *
 * RCU is locked, no other locks set
 */
void tipc_bclink_rcv(struct net *net, struct sk_buff *buf)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_link *bcl = tn->bcl;
	struct tipc_msg *msg = buf_msg(buf);
	struct tipc_node *node;
	u32 next_in;
	u32 seqno;
	int deferred = 0;
	int pos = 0;
	struct sk_buff *iskb;
	struct sk_buff_head *arrvq, *inputq;

	/* Screen out unwanted broadcast messages */
	if (msg_mc_netid(msg) != tn->net_id)
		goto exit;

	node = tipc_node_find(net, msg_prevnode(msg));
	if (unlikely(!node))
		goto exit;

	tipc_node_lock(node);
	if (unlikely(!node->bclink.recv_permitted))
		goto unlock;

	/* Handle broadcast protocol message */
	if (unlikely(msg_user(msg) == BCAST_PROTOCOL)) {
		if (msg_type(msg) != STATE_MSG)
			goto unlock;
		if (msg_destnode(msg) == tn->own_addr) {
			tipc_bclink_acknowledge(node, msg_bcast_ack(msg));
			tipc_node_unlock(node);
			tipc_bclink_lock(net);
			bcl->stats.recv_nacks++;
			tn->bclink->retransmit_to = node;
			bclink_retransmit_pkt(tn, msg_bcgap_after(msg),
					      msg_bcgap_to(msg));
			tipc_bclink_unlock(net);
		} else {
			tipc_node_unlock(node);
			bclink_peek_nack(net, msg);
		}
		goto exit;
	}

	/* Handle in-sequence broadcast message */
	seqno = msg_seqno(msg);
	next_in = mod(node->bclink.last_in + 1);
	arrvq = &tn->bclink->arrvq;
	inputq = &tn->bclink->inputq;

	if (likely(seqno == next_in)) {
receive:
		/* Deliver message to destination */
		if (likely(msg_isdata(msg))) {
			tipc_bclink_lock(net);
			bclink_accept_pkt(node, seqno);
			spin_lock_bh(&inputq->lock);
			__skb_queue_tail(arrvq, buf);
			spin_unlock_bh(&inputq->lock);
			node->action_flags |= TIPC_BCAST_MSG_EVT;
			tipc_bclink_unlock(net);
			tipc_node_unlock(node);
		} else if (msg_user(msg) == MSG_BUNDLER) {
			tipc_bclink_lock(net);
			bclink_accept_pkt(node, seqno);
			bcl->stats.recv_bundles++;
			bcl->stats.recv_bundled += msg_msgcnt(msg);
			pos = 0;
			while (tipc_msg_extract(buf, &iskb, &pos)) {
				spin_lock_bh(&inputq->lock);
				__skb_queue_tail(arrvq, iskb);
				spin_unlock_bh(&inputq->lock);
			}
			node->action_flags |= TIPC_BCAST_MSG_EVT;
			tipc_bclink_unlock(net);
			tipc_node_unlock(node);
		} else if (msg_user(msg) == MSG_FRAGMENTER) {
			tipc_buf_append(&node->bclink.reasm_buf, &buf);
			if (unlikely(!buf && !node->bclink.reasm_buf))
				goto unlock;
			tipc_bclink_lock(net);
			bclink_accept_pkt(node, seqno);
			bcl->stats.recv_fragments++;
			if (buf) {
				bcl->stats.recv_fragmented++;
				msg = buf_msg(buf);
				tipc_bclink_unlock(net);
				goto receive;
			}
			tipc_bclink_unlock(net);
			tipc_node_unlock(node);
		} else {
			tipc_bclink_lock(net);
			bclink_accept_pkt(node, seqno);
			tipc_bclink_unlock(net);
			tipc_node_unlock(node);
			kfree_skb(buf);
		}
		buf = NULL;

		/* Determine new synchronization state */
		tipc_node_lock(node);
		if (unlikely(!tipc_node_is_up(node)))
			goto unlock;

		if (node->bclink.last_in == node->bclink.last_sent)
			goto unlock;

		if (skb_queue_empty(&node->bclink.deferred_queue)) {
			node->bclink.oos_state = 1;
			goto unlock;
		}

		msg = buf_msg(skb_peek(&node->bclink.deferred_queue));
		seqno = msg_seqno(msg);
		next_in = mod(next_in + 1);
		if (seqno != next_in)
			goto unlock;

		/* Take in-sequence message from deferred queue & deliver it */
		buf = __skb_dequeue(&node->bclink.deferred_queue);
		goto receive;
	}

	/* Handle out-of-sequence broadcast message */
	if (less(next_in, seqno)) {
		deferred = tipc_link_defer_pkt(&node->bclink.deferred_queue,
					       buf);
		bclink_update_last_sent(node, seqno);
		buf = NULL;
	}

	tipc_bclink_lock(net);

	if (deferred)
		bcl->stats.deferred_recv++;
	else
		bcl->stats.duplicates++;

	tipc_bclink_unlock(net);

unlock:
	tipc_node_unlock(node);
exit:
	kfree_skb(buf);
}

u32 tipc_bclink_acks_missing(struct tipc_node *n_ptr)
{
	return (n_ptr->bclink.recv_permitted &&
		(tipc_bclink_get_last_sent(n_ptr->net) != n_ptr->bclink.acked));
}


/**
 * tipc_bcbearer_send - send a packet through the broadcast pseudo-bearer
 *
 * Send packet over as many bearers as necessary to reach all nodes
 * that have joined the broadcast link.
 *
 * Returns 0 (packet sent successfully) under all circumstances,
 * since the broadcast link's pseudo-bearer never blocks
 */
static int tipc_bcbearer_send(struct net *net, struct sk_buff *buf,
			      struct tipc_bearer *unused1,
			      struct tipc_media_addr *unused2)
{
	int bp_index;
	struct tipc_msg *msg = buf_msg(buf);
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_bcbearer *bcbearer = tn->bcbearer;
	struct tipc_bclink *bclink = tn->bclink;

	/* Prepare broadcast link message for reliable transmission,
	 * if first time trying to send it;
	 * preparation is skipped for broadcast link protocol messages
	 * since they are sent in an unreliable manner and don't need it
	 */
	if (likely(!msg_non_seq(buf_msg(buf)))) {
		bcbuf_set_acks(buf, bclink->bcast_nodes.count);
		msg_set_non_seq(msg, 1);
		msg_set_mc_netid(msg, tn->net_id);
		tn->bcl->stats.sent_info++;

		if (WARN_ON(!bclink->bcast_nodes.count)) {
			dump_stack();
			return 0;
		}
	}

	/* Send buffer over bearers until all targets reached */
	bcbearer->remains = bclink->bcast_nodes;

	for (bp_index = 0; bp_index < MAX_BEARERS; bp_index++) {
		struct tipc_bearer *p = bcbearer->bpairs[bp_index].primary;
		struct tipc_bearer *s = bcbearer->bpairs[bp_index].secondary;
		struct tipc_bearer *bp[2] = {p, s};
		struct tipc_bearer *b = bp[msg_link_selector(msg)];
		struct sk_buff *tbuf;

		if (!p)
			break; /* No more bearers to try */
		if (!b)
			b = p;
		tipc_nmap_diff(&bcbearer->remains, &b->nodes,
			       &bcbearer->remains_new);
		if (bcbearer->remains_new.count == bcbearer->remains.count)
			continue; /* Nothing added by bearer pair */

		if (bp_index == 0) {
			/* Use original buffer for first bearer */
			tipc_bearer_send(net, b->identity, buf, &b->bcast_addr);
		} else {
			/* Avoid concurrent buffer access */
			tbuf = pskb_copy_for_clone(buf, GFP_ATOMIC);
			if (!tbuf)
				break;
			tipc_bearer_send(net, b->identity, tbuf,
					 &b->bcast_addr);
			kfree_skb(tbuf); /* Bearer keeps a clone */
		}
		if (bcbearer->remains_new.count == 0)
			break; /* All targets reached */

		bcbearer->remains = bcbearer->remains_new;
	}

	return 0;
}

/**
 * tipc_bcbearer_sort - create sets of bearer pairs used by broadcast bearer
 */
void tipc_bcbearer_sort(struct net *net, struct tipc_node_map *nm_ptr,
			u32 node, bool action)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_bcbearer *bcbearer = tn->bcbearer;
	struct tipc_bcbearer_pair *bp_temp = bcbearer->bpairs_temp;
	struct tipc_bcbearer_pair *bp_curr;
	struct tipc_bearer *b;
	int b_index;
	int pri;

	tipc_bclink_lock(net);

	if (action)
		tipc_nmap_add(nm_ptr, node);
	else
		tipc_nmap_remove(nm_ptr, node);

	/* Group bearers by priority (can assume max of two per priority) */
	memset(bp_temp, 0, sizeof(bcbearer->bpairs_temp));

	rcu_read_lock();
	for (b_index = 0; b_index < MAX_BEARERS; b_index++) {
		b = rcu_dereference_rtnl(tn->bearer_list[b_index]);
		if (!b || !b->nodes.count)
			continue;

		if (!bp_temp[b->priority].primary)
			bp_temp[b->priority].primary = b;
		else
			bp_temp[b->priority].secondary = b;
	}
	rcu_read_unlock();

	/* Create array of bearer pairs for broadcasting */
	bp_curr = bcbearer->bpairs;
	memset(bcbearer->bpairs, 0, sizeof(bcbearer->bpairs));

	for (pri = TIPC_MAX_LINK_PRI; pri >= 0; pri--) {

		if (!bp_temp[pri].primary)
			continue;

		bp_curr->primary = bp_temp[pri].primary;

		if (bp_temp[pri].secondary) {
			if (tipc_nmap_equal(&bp_temp[pri].primary->nodes,
					    &bp_temp[pri].secondary->nodes)) {
				bp_curr->secondary = bp_temp[pri].secondary;
			} else {
				bp_curr++;
				bp_curr->primary = bp_temp[pri].secondary;
			}
		}

		bp_curr++;
	}

	tipc_bclink_unlock(net);
}

static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
				      struct tipc_stats *stats)
{
	int i;
	struct nlattr *nest;

	struct nla_map {
		__u32 key;
		__u32 val;
	};

	struct nla_map map[] = {
		{TIPC_NLA_STATS_RX_INFO, stats->recv_info},
		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
		{TIPC_NLA_STATS_TX_INFO, stats->sent_info},
		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
	};

	nest = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
	if (!nest)
		return -EMSGSIZE;

	for (i = 0; i <  ARRAY_SIZE(map); i++)
		if (nla_put_u32(skb, map[i].key, map[i].val))
			goto msg_full;

	nla_nest_end(skb, nest);

	return 0;
msg_full:
	nla_nest_cancel(skb, nest);

	return -EMSGSIZE;
}

int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg)
{
	int err;
	void *hdr;
	struct nlattr *attrs;
	struct nlattr *prop;
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_link *bcl = tn->bcl;

	if (!bcl)
		return 0;

	tipc_bclink_lock(net);

	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
			  NLM_F_MULTI, TIPC_NL_LINK_GET);
	if (!hdr)
		return -EMSGSIZE;

	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
	if (!attrs)
		goto msg_full;

	/* The broadcast link is always up */
	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
		goto attr_msg_full;

	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
		goto attr_msg_full;
	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, bcl->next_in_no))
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, bcl->next_out_no))
		goto attr_msg_full;

	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
	if (!prop)
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->queue_limit[0]))
		goto prop_msg_full;
	nla_nest_end(msg->skb, prop);

	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
	if (err)
		goto attr_msg_full;

	tipc_bclink_unlock(net);
	nla_nest_end(msg->skb, attrs);
	genlmsg_end(msg->skb, hdr);

	return 0;

prop_msg_full:
	nla_nest_cancel(msg->skb, prop);
attr_msg_full:
	nla_nest_cancel(msg->skb, attrs);
msg_full:
	tipc_bclink_unlock(net);
	genlmsg_cancel(msg->skb, hdr);

	return -EMSGSIZE;
}

int tipc_bclink_reset_stats(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_link *bcl = tn->bcl;

	if (!bcl)
		return -ENOPROTOOPT;

	tipc_bclink_lock(net);
	memset(&bcl->stats, 0, sizeof(bcl->stats));
	tipc_bclink_unlock(net);
	return 0;
}

int tipc_bclink_set_queue_limits(struct net *net, u32 limit)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_link *bcl = tn->bcl;

	if (!bcl)
		return -ENOPROTOOPT;
	if ((limit < TIPC_MIN_LINK_WIN) || (limit > TIPC_MAX_LINK_WIN))
		return -EINVAL;

	tipc_bclink_lock(net);
	tipc_link_set_queue_limits(bcl, limit);
	tipc_bclink_unlock(net);
	return 0;
}

int tipc_bclink_init(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_bcbearer *bcbearer;
	struct tipc_bclink *bclink;
	struct tipc_link *bcl;

	bcbearer = kzalloc(sizeof(*bcbearer), GFP_ATOMIC);
	if (!bcbearer)
		return -ENOMEM;

	bclink = kzalloc(sizeof(*bclink), GFP_ATOMIC);
	if (!bclink) {
		kfree(bcbearer);
		return -ENOMEM;
	}

	bcl = &bclink->link;
	bcbearer->bearer.media = &bcbearer->media;
	bcbearer->media.send_msg = tipc_bcbearer_send;
	sprintf(bcbearer->media.name, "tipc-broadcast");

	spin_lock_init(&bclink->lock);
	__skb_queue_head_init(&bcl->outqueue);
	__skb_queue_head_init(&bcl->deferred_queue);
	skb_queue_head_init(&bcl->wakeupq);
	bcl->next_out_no = 1;
	spin_lock_init(&bclink->node.lock);
	__skb_queue_head_init(&bclink->arrvq);
	skb_queue_head_init(&bclink->inputq);
	bcl->owner = &bclink->node;
	bcl->owner->net = net;
	bcl->max_pkt = MAX_PKT_DEFAULT_MCAST;
	tipc_link_set_queue_limits(bcl, BCLINK_WIN_DEFAULT);
	bcl->bearer_id = MAX_BEARERS;
	rcu_assign_pointer(tn->bearer_list[MAX_BEARERS], &bcbearer->bearer);
	bcl->state = WORKING_WORKING;
	bcl->pmsg = (struct tipc_msg *)&bcl->proto_msg;
	msg_set_prevnode(bcl->pmsg, tn->own_addr);
	strlcpy(bcl->name, tipc_bclink_name, TIPC_MAX_LINK_NAME);
	tn->bcbearer = bcbearer;
	tn->bclink = bclink;
	tn->bcl = bcl;
	return 0;
}

void tipc_bclink_stop(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	tipc_bclink_lock(net);
	tipc_link_purge_queues(tn->bcl);
	tipc_bclink_unlock(net);

	RCU_INIT_POINTER(tn->bearer_list[BCBEARER], NULL);
	synchronize_net();
	kfree(tn->bcbearer);
	kfree(tn->bclink);
}

/**
 * tipc_nmap_add - add a node to a node map
 */
static void tipc_nmap_add(struct tipc_node_map *nm_ptr, u32 node)
{
	int n = tipc_node(node);
	int w = n / WSIZE;
	u32 mask = (1 << (n % WSIZE));

	if ((nm_ptr->map[w] & mask) == 0) {
		nm_ptr->count++;
		nm_ptr->map[w] |= mask;
	}
}

/**
 * tipc_nmap_remove - remove a node from a node map
 */
static void tipc_nmap_remove(struct tipc_node_map *nm_ptr, u32 node)
{
	int n = tipc_node(node);
	int w = n / WSIZE;
	u32 mask = (1 << (n % WSIZE));

	if ((nm_ptr->map[w] & mask) != 0) {
		nm_ptr->map[w] &= ~mask;
		nm_ptr->count--;
	}
}

/**
 * tipc_nmap_diff - find differences between node maps
 * @nm_a: input node map A
 * @nm_b: input node map B
 * @nm_diff: output node map A-B (i.e. nodes of A that are not in B)
 */
static void tipc_nmap_diff(struct tipc_node_map *nm_a,
			   struct tipc_node_map *nm_b,
			   struct tipc_node_map *nm_diff)
{
	int stop = ARRAY_SIZE(nm_a->map);
	int w;
	int b;
	u32 map;

	memset(nm_diff, 0, sizeof(*nm_diff));
	for (w = 0; w < stop; w++) {
		map = nm_a->map[w] ^ (nm_a->map[w] & nm_b->map[w]);
		nm_diff->map[w] = map;
		if (map != 0) {
			for (b = 0 ; b < WSIZE; b++) {
				if (map & (1 << b))
					nm_diff->count++;
			}
		}
	}
}