summaryrefslogtreecommitdiffstats
path: root/net/tipc/node.c
blob: 20cddec0a43c7227a6e3aff860286ec04f9cd423 (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
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
/*
 * net/tipc/node.c: TIPC node management routines
 *
 * Copyright (c) 2000-2006, 2012-2015, Ericsson AB
 * Copyright (c) 2005-2006, 2010-2014, 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 "core.h"
#include "link.h"
#include "node.h"
#include "name_distr.h"
#include "socket.h"
#include "bcast.h"
#include "discover.h"

/* Node FSM states and events:
 */
enum {
	SELF_DOWN_PEER_DOWN    = 0xdd,
	SELF_UP_PEER_UP        = 0xaa,
	SELF_DOWN_PEER_LEAVING = 0xd1,
	SELF_UP_PEER_COMING    = 0xac,
	SELF_COMING_PEER_UP    = 0xca,
	SELF_LEAVING_PEER_DOWN = 0x1d,
	NODE_FAILINGOVER       = 0xf0,
	NODE_SYNCHING          = 0xcc
};

enum {
	SELF_ESTABL_CONTACT_EVT = 0xece,
	SELF_LOST_CONTACT_EVT   = 0x1ce,
	PEER_ESTABL_CONTACT_EVT = 0x9ece,
	PEER_LOST_CONTACT_EVT   = 0x91ce,
	NODE_FAILOVER_BEGIN_EVT = 0xfbe,
	NODE_FAILOVER_END_EVT   = 0xfee,
	NODE_SYNCH_BEGIN_EVT    = 0xcbe,
	NODE_SYNCH_END_EVT      = 0xcee
};

static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
				  struct sk_buff_head *xmitq,
				  struct tipc_media_addr **maddr);
static void tipc_node_link_down(struct tipc_node *n, int bearer_id,
				bool delete);
static void node_lost_contact(struct tipc_node *n, struct sk_buff_head *inputq);
static void tipc_node_delete(struct tipc_node *node);
static void tipc_node_timeout(unsigned long data);
static void tipc_node_fsm_evt(struct tipc_node *n, int evt);

struct tipc_sock_conn {
	u32 port;
	u32 peer_port;
	u32 peer_node;
	struct list_head list;
};

static const struct nla_policy tipc_nl_node_policy[TIPC_NLA_NODE_MAX + 1] = {
	[TIPC_NLA_NODE_UNSPEC]		= { .type = NLA_UNSPEC },
	[TIPC_NLA_NODE_ADDR]		= { .type = NLA_U32 },
	[TIPC_NLA_NODE_UP]		= { .type = NLA_FLAG }
};

/*
 * A trivial power-of-two bitmask technique is used for speed, since this
 * operation is done for every incoming TIPC packet. The number of hash table
 * entries has been chosen so that no hash chain exceeds 8 nodes and will
 * usually be much smaller (typically only a single node).
 */
static unsigned int tipc_hashfn(u32 addr)
{
	return addr & (NODE_HTABLE_SIZE - 1);
}

static void tipc_node_kref_release(struct kref *kref)
{
	struct tipc_node *node = container_of(kref, struct tipc_node, kref);

	tipc_node_delete(node);
}

void tipc_node_put(struct tipc_node *node)
{
	kref_put(&node->kref, tipc_node_kref_release);
}

static void tipc_node_get(struct tipc_node *node)
{
	kref_get(&node->kref);
}

/*
 * tipc_node_find - locate specified node object, if it exists
 */
struct tipc_node *tipc_node_find(struct net *net, u32 addr)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_node *node;

	if (unlikely(!in_own_cluster_exact(net, addr)))
		return NULL;

	rcu_read_lock();
	hlist_for_each_entry_rcu(node, &tn->node_htable[tipc_hashfn(addr)],
				 hash) {
		if (node->addr == addr) {
			tipc_node_get(node);
			rcu_read_unlock();
			return node;
		}
	}
	rcu_read_unlock();
	return NULL;
}

struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_node *n_ptr, *temp_node;

	spin_lock_bh(&tn->node_list_lock);
	n_ptr = tipc_node_find(net, addr);
	if (n_ptr)
		goto exit;
	n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
	if (!n_ptr) {
		pr_warn("Node creation failed, no memory\n");
		goto exit;
	}
	n_ptr->addr = addr;
	n_ptr->net = net;
	n_ptr->capabilities = capabilities;
	kref_init(&n_ptr->kref);
	spin_lock_init(&n_ptr->lock);
	INIT_HLIST_NODE(&n_ptr->hash);
	INIT_LIST_HEAD(&n_ptr->list);
	INIT_LIST_HEAD(&n_ptr->publ_list);
	INIT_LIST_HEAD(&n_ptr->conn_sks);
	skb_queue_head_init(&n_ptr->bc_entry.namedq);
	skb_queue_head_init(&n_ptr->bc_entry.inputq1);
	__skb_queue_head_init(&n_ptr->bc_entry.arrvq);
	skb_queue_head_init(&n_ptr->bc_entry.inputq2);
	hlist_add_head_rcu(&n_ptr->hash, &tn->node_htable[tipc_hashfn(addr)]);
	list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
		if (n_ptr->addr < temp_node->addr)
			break;
	}
	list_add_tail_rcu(&n_ptr->list, &temp_node->list);
	n_ptr->state = SELF_DOWN_PEER_LEAVING;
	n_ptr->signature = INVALID_NODE_SIG;
	n_ptr->active_links[0] = INVALID_BEARER_ID;
	n_ptr->active_links[1] = INVALID_BEARER_ID;
	if (!tipc_link_bc_create(net, tipc_own_addr(net), n_ptr->addr,
				 U16_MAX, tipc_bc_sndlink(net)->window,
				 n_ptr->capabilities,
				 &n_ptr->bc_entry.inputq1,
				 &n_ptr->bc_entry.namedq,
				 tipc_bc_sndlink(net),
				 &n_ptr->bc_entry.link)) {
		pr_warn("Broadcast rcv link creation failed, no memory\n");
		kfree(n_ptr);
		n_ptr = NULL;
		goto exit;
	}
	tipc_node_get(n_ptr);
	setup_timer(&n_ptr->timer, tipc_node_timeout, (unsigned long)n_ptr);
	n_ptr->keepalive_intv = U32_MAX;
exit:
	spin_unlock_bh(&tn->node_list_lock);
	return n_ptr;
}

static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
{
	unsigned long tol = l->tolerance;
	unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
	unsigned long keepalive_intv = msecs_to_jiffies(intv);

	/* Link with lowest tolerance determines timer interval */
	if (keepalive_intv < n->keepalive_intv)
		n->keepalive_intv = keepalive_intv;

	/* Ensure link's abort limit corresponds to current interval */
	l->abort_limit = l->tolerance / jiffies_to_msecs(n->keepalive_intv);
}

static void tipc_node_delete(struct tipc_node *node)
{
	list_del_rcu(&node->list);
	hlist_del_rcu(&node->hash);
	kfree(node->bc_entry.link);
	kfree_rcu(node, rcu);
}

void tipc_node_stop(struct net *net)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_node *node, *t_node;

	spin_lock_bh(&tn->node_list_lock);
	list_for_each_entry_safe(node, t_node, &tn->node_list, list) {
		if (del_timer(&node->timer))
			tipc_node_put(node);
		tipc_node_put(node);
	}
	spin_unlock_bh(&tn->node_list_lock);
}

int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
{
	struct tipc_node *node;
	struct tipc_sock_conn *conn;
	int err = 0;

	if (in_own_node(net, dnode))
		return 0;

	node = tipc_node_find(net, dnode);
	if (!node) {
		pr_warn("Connecting sock to node 0x%x failed\n", dnode);
		return -EHOSTUNREACH;
	}
	conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
	if (!conn) {
		err = -EHOSTUNREACH;
		goto exit;
	}
	conn->peer_node = dnode;
	conn->port = port;
	conn->peer_port = peer_port;

	tipc_node_lock(node);
	list_add_tail(&conn->list, &node->conn_sks);
	tipc_node_unlock(node);
exit:
	tipc_node_put(node);
	return err;
}

void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
{
	struct tipc_node *node;
	struct tipc_sock_conn *conn, *safe;

	if (in_own_node(net, dnode))
		return;

	node = tipc_node_find(net, dnode);
	if (!node)
		return;

	tipc_node_lock(node);
	list_for_each_entry_safe(conn, safe, &node->conn_sks, list) {
		if (port != conn->port)
			continue;
		list_del(&conn->list);
		kfree(conn);
	}
	tipc_node_unlock(node);
	tipc_node_put(node);
}

/* tipc_node_timeout - handle expiration of node timer
 */
static void tipc_node_timeout(unsigned long data)
{
	struct tipc_node *n = (struct tipc_node *)data;
	struct tipc_link_entry *le;
	struct sk_buff_head xmitq;
	int bearer_id;
	int rc = 0;

	__skb_queue_head_init(&xmitq);

	for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
		tipc_node_lock(n);
		le = &n->links[bearer_id];
		if (le->link) {
			/* Link tolerance may change asynchronously: */
			tipc_node_calculate_timer(n, le->link);
			rc = tipc_link_timeout(le->link, &xmitq);
		}
		tipc_node_unlock(n);
		tipc_bearer_xmit(n->net, bearer_id, &xmitq, &le->maddr);
		if (rc & TIPC_LINK_DOWN_EVT)
			tipc_node_link_down(n, bearer_id, false);
	}
	if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
		tipc_node_get(n);
	tipc_node_put(n);
}

/**
 * __tipc_node_link_up - handle addition of link
 * Node lock must be held by caller
 * Link becomes active (alone or shared) or standby, depending on its priority.
 */
static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
				struct sk_buff_head *xmitq)
{
	int *slot0 = &n->active_links[0];
	int *slot1 = &n->active_links[1];
	struct tipc_link *ol = node_active_link(n, 0);
	struct tipc_link *nl = n->links[bearer_id].link;

	if (!nl)
		return;

	tipc_link_fsm_evt(nl, LINK_ESTABLISH_EVT);
	if (!tipc_link_is_up(nl))
		return;

	n->working_links++;
	n->action_flags |= TIPC_NOTIFY_LINK_UP;
	n->link_id = nl->peer_bearer_id << 16 | bearer_id;

	/* Leave room for tunnel header when returning 'mtu' to users: */
	n->links[bearer_id].mtu = nl->mtu - INT_H_SIZE;

	tipc_bearer_add_dest(n->net, bearer_id, n->addr);
	tipc_bcast_inc_bearer_dst_cnt(n->net, bearer_id);

	pr_debug("Established link <%s> on network plane %c\n",
		 nl->name, nl->net_plane);

	/* First link? => give it both slots */
	if (!ol) {
		*slot0 = bearer_id;
		*slot1 = bearer_id;
		tipc_node_fsm_evt(n, SELF_ESTABL_CONTACT_EVT);
		n->action_flags |= TIPC_NOTIFY_NODE_UP;
		tipc_bcast_add_peer(n->net, nl, xmitq);
		return;
	}

	/* Second link => redistribute slots */
	if (nl->priority > ol->priority) {
		pr_debug("Old link <%s> becomes standby\n", ol->name);
		*slot0 = bearer_id;
		*slot1 = bearer_id;
		tipc_link_set_active(nl, true);
		tipc_link_set_active(ol, false);
	} else if (nl->priority == ol->priority) {
		tipc_link_set_active(nl, true);
		*slot1 = bearer_id;
	} else {
		pr_debug("New link <%s> is standby\n", nl->name);
	}

	/* Prepare synchronization with first link */
	tipc_link_tnl_prepare(ol, nl, SYNCH_MSG, xmitq);
}

/**
 * tipc_node_link_up - handle addition of link
 *
 * Link becomes active (alone or shared) or standby, depending on its priority.
 */
static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
			      struct sk_buff_head *xmitq)
{
	tipc_node_lock(n);
	__tipc_node_link_up(n, bearer_id, xmitq);
	tipc_node_unlock(n);
}

/**
 * __tipc_node_link_down - handle loss of link
 */
static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
				  struct sk_buff_head *xmitq,
				  struct tipc_media_addr **maddr)
{
	struct tipc_link_entry *le = &n->links[*bearer_id];
	int *slot0 = &n->active_links[0];
	int *slot1 = &n->active_links[1];
	int i, highest = 0;
	struct tipc_link *l, *_l, *tnl;

	l = n->links[*bearer_id].link;
	if (!l || tipc_link_is_reset(l))
		return;

	n->working_links--;
	n->action_flags |= TIPC_NOTIFY_LINK_DOWN;
	n->link_id = l->peer_bearer_id << 16 | *bearer_id;

	tipc_bearer_remove_dest(n->net, *bearer_id, n->addr);

	pr_debug("Lost link <%s> on network plane %c\n",
		 l->name, l->net_plane);

	/* Select new active link if any available */
	*slot0 = INVALID_BEARER_ID;
	*slot1 = INVALID_BEARER_ID;
	for (i = 0; i < MAX_BEARERS; i++) {
		_l = n->links[i].link;
		if (!_l || !tipc_link_is_up(_l))
			continue;
		if (_l == l)
			continue;
		if (_l->priority < highest)
			continue;
		if (_l->priority > highest) {
			highest = _l->priority;
			*slot0 = i;
			*slot1 = i;
			continue;
		}
		*slot1 = i;
	}

	if (!tipc_node_is_up(n)) {
		if (tipc_link_peer_is_down(l))
			tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
		tipc_node_fsm_evt(n, SELF_LOST_CONTACT_EVT);
		tipc_link_fsm_evt(l, LINK_RESET_EVT);
		tipc_link_reset(l);
		tipc_link_build_reset_msg(l, xmitq);
		*maddr = &n->links[*bearer_id].maddr;
		node_lost_contact(n, &le->inputq);
		tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);
		return;
	}
	tipc_bcast_dec_bearer_dst_cnt(n->net, *bearer_id);

	/* There is still a working link => initiate failover */
	tnl = node_active_link(n, 0);
	tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
	tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
	n->sync_point = tnl->rcv_nxt + (U16_MAX / 2 - 1);
	tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, xmitq);
	tipc_link_reset(l);
	tipc_link_fsm_evt(l, LINK_RESET_EVT);
	tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
	tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);
	*maddr = &n->links[tnl->bearer_id].maddr;
	*bearer_id = tnl->bearer_id;
}

static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
{
	struct tipc_link_entry *le = &n->links[bearer_id];
	struct tipc_link *l = le->link;
	struct tipc_media_addr *maddr;
	struct sk_buff_head xmitq;

	if (!l)
		return;

	__skb_queue_head_init(&xmitq);

	tipc_node_lock(n);
	if (!tipc_link_is_establishing(l)) {
		__tipc_node_link_down(n, &bearer_id, &xmitq, &maddr);
		if (delete) {
			kfree(l);
			le->link = NULL;
			n->link_cnt--;
		}
	} else {
		/* Defuse pending tipc_node_link_up() */
		tipc_link_fsm_evt(l, LINK_RESET_EVT);
	}
	tipc_node_unlock(n);
	tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
	tipc_sk_rcv(n->net, &le->inputq);
}

bool tipc_node_is_up(struct tipc_node *n)
{
	return n->active_links[0] != INVALID_BEARER_ID;
}

void tipc_node_check_dest(struct net *net, u32 onode,
			  struct tipc_bearer *b,
			  u16 capabilities, u32 signature,
			  struct tipc_media_addr *maddr,
			  bool *respond, bool *dupl_addr)
{
	struct tipc_node *n;
	struct tipc_link *l;
	struct tipc_link_entry *le;
	bool addr_match = false;
	bool sign_match = false;
	bool link_up = false;
	bool accept_addr = false;
	bool reset = true;
	char *if_name;

	*dupl_addr = false;
	*respond = false;

	n = tipc_node_create(net, onode, capabilities);
	if (!n)
		return;

	tipc_node_lock(n);

	le = &n->links[b->identity];

	/* Prepare to validate requesting node's signature and media address */
	l = le->link;
	link_up = l && tipc_link_is_up(l);
	addr_match = l && !memcmp(&le->maddr, maddr, sizeof(*maddr));
	sign_match = (signature == n->signature);

	/* These three flags give us eight permutations: */

	if (sign_match && addr_match && link_up) {
		/* All is fine. Do nothing. */
		reset = false;
	} else if (sign_match && addr_match && !link_up) {
		/* Respond. The link will come up in due time */
		*respond = true;
	} else if (sign_match && !addr_match && link_up) {
		/* Peer has changed i/f address without rebooting.
		 * If so, the link will reset soon, and the next
		 * discovery will be accepted. So we can ignore it.
		 * It may also be an cloned or malicious peer having
		 * chosen the same node address and signature as an
		 * existing one.
		 * Ignore requests until the link goes down, if ever.
		 */
		*dupl_addr = true;
	} else if (sign_match && !addr_match && !link_up) {
		/* Peer link has changed i/f address without rebooting.
		 * It may also be a cloned or malicious peer; we can't
		 * distinguish between the two.
		 * The signature is correct, so we must accept.
		 */
		accept_addr = true;
		*respond = true;
	} else if (!sign_match && addr_match && link_up) {
		/* Peer node rebooted. Two possibilities:
		 *  - Delayed re-discovery; this link endpoint has already
		 *    reset and re-established contact with the peer, before
		 *    receiving a discovery message from that node.
		 *    (The peer happened to receive one from this node first).
		 *  - The peer came back so fast that our side has not
		 *    discovered it yet. Probing from this side will soon
		 *    reset the link, since there can be no working link
		 *    endpoint at the peer end, and the link will re-establish.
		 *  Accept the signature, since it comes from a known peer.
		 */
		n->signature = signature;
	} else if (!sign_match && addr_match && !link_up) {
		/*  The peer node has rebooted.
		 *  Accept signature, since it is a known peer.
		 */
		n->signature = signature;
		*respond = true;
	} else if (!sign_match && !addr_match && link_up) {
		/* Peer rebooted with new address, or a new/duplicate peer.
		 * Ignore until the link goes down, if ever.
		 */
		*dupl_addr = true;
	} else if (!sign_match && !addr_match && !link_up) {
		/* Peer rebooted with new address, or it is a new peer.
		 * Accept signature and address.
		 */
		n->signature = signature;
		accept_addr = true;
		*respond = true;
	}

	if (!accept_addr)
		goto exit;

	/* Now create new link if not already existing */
	if (!l) {
		if (n->link_cnt == 2) {
			pr_warn("Cannot establish 3rd link to %x\n", n->addr);
			goto exit;
		}
		if_name = strchr(b->name, ':') + 1;
		if (!tipc_link_create(net, if_name, b->identity, b->tolerance,
				      b->net_plane, b->mtu, b->priority,
				      b->window, mod(tipc_net(net)->random),
				      tipc_own_addr(net), onode,
				      n->capabilities,
				      tipc_bc_sndlink(n->net), n->bc_entry.link,
				      &le->inputq,
				      &n->bc_entry.namedq, &l)) {
			*respond = false;
			goto exit;
		}
		tipc_link_reset(l);
		tipc_link_fsm_evt(l, LINK_RESET_EVT);
		if (n->state == NODE_FAILINGOVER)
			tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);
		le->link = l;
		n->link_cnt++;
		tipc_node_calculate_timer(n, l);
		if (n->link_cnt == 1)
			if (!mod_timer(&n->timer, jiffies + n->keepalive_intv))
				tipc_node_get(n);
	}
	memcpy(&le->maddr, maddr, sizeof(*maddr));
exit:
	tipc_node_unlock(n);
	if (reset && !tipc_link_is_reset(l))
		tipc_node_link_down(n, b->identity, false);
	tipc_node_put(n);
}

void tipc_node_delete_links(struct net *net, int bearer_id)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_node *n;

	rcu_read_lock();
	list_for_each_entry_rcu(n, &tn->node_list, list) {
		tipc_node_link_down(n, bearer_id, true);
	}
	rcu_read_unlock();
}

static void tipc_node_reset_links(struct tipc_node *n)
{
	char addr_string[16];
	int i;

	pr_warn("Resetting all links to %s\n",
		tipc_addr_string_fill(addr_string, n->addr));

	for (i = 0; i < MAX_BEARERS; i++) {
		tipc_node_link_down(n, i, false);
	}
}

/* tipc_node_fsm_evt - node finite state machine
 * Determines when contact is allowed with peer node
 */
static void tipc_node_fsm_evt(struct tipc_node *n, int evt)
{
	int state = n->state;

	switch (state) {
	case SELF_DOWN_PEER_DOWN:
		switch (evt) {
		case SELF_ESTABL_CONTACT_EVT:
			state = SELF_UP_PEER_COMING;
			break;
		case PEER_ESTABL_CONTACT_EVT:
			state = SELF_COMING_PEER_UP;
			break;
		case SELF_LOST_CONTACT_EVT:
		case PEER_LOST_CONTACT_EVT:
			break;
		case NODE_SYNCH_END_EVT:
		case NODE_SYNCH_BEGIN_EVT:
		case NODE_FAILOVER_BEGIN_EVT:
		case NODE_FAILOVER_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case SELF_UP_PEER_UP:
		switch (evt) {
		case SELF_LOST_CONTACT_EVT:
			state = SELF_DOWN_PEER_LEAVING;
			break;
		case PEER_LOST_CONTACT_EVT:
			state = SELF_LEAVING_PEER_DOWN;
			break;
		case NODE_SYNCH_BEGIN_EVT:
			state = NODE_SYNCHING;
			break;
		case NODE_FAILOVER_BEGIN_EVT:
			state = NODE_FAILINGOVER;
			break;
		case SELF_ESTABL_CONTACT_EVT:
		case PEER_ESTABL_CONTACT_EVT:
		case NODE_SYNCH_END_EVT:
		case NODE_FAILOVER_END_EVT:
			break;
		default:
			goto illegal_evt;
		}
		break;
	case SELF_DOWN_PEER_LEAVING:
		switch (evt) {
		case PEER_LOST_CONTACT_EVT:
			state = SELF_DOWN_PEER_DOWN;
			break;
		case SELF_ESTABL_CONTACT_EVT:
		case PEER_ESTABL_CONTACT_EVT:
		case SELF_LOST_CONTACT_EVT:
			break;
		case NODE_SYNCH_END_EVT:
		case NODE_SYNCH_BEGIN_EVT:
		case NODE_FAILOVER_BEGIN_EVT:
		case NODE_FAILOVER_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case SELF_UP_PEER_COMING:
		switch (evt) {
		case PEER_ESTABL_CONTACT_EVT:
			state = SELF_UP_PEER_UP;
			break;
		case SELF_LOST_CONTACT_EVT:
			state = SELF_DOWN_PEER_LEAVING;
			break;
		case SELF_ESTABL_CONTACT_EVT:
		case PEER_LOST_CONTACT_EVT:
		case NODE_SYNCH_END_EVT:
		case NODE_FAILOVER_BEGIN_EVT:
			break;
		case NODE_SYNCH_BEGIN_EVT:
		case NODE_FAILOVER_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case SELF_COMING_PEER_UP:
		switch (evt) {
		case SELF_ESTABL_CONTACT_EVT:
			state = SELF_UP_PEER_UP;
			break;
		case PEER_LOST_CONTACT_EVT:
			state = SELF_LEAVING_PEER_DOWN;
			break;
		case SELF_LOST_CONTACT_EVT:
		case PEER_ESTABL_CONTACT_EVT:
			break;
		case NODE_SYNCH_END_EVT:
		case NODE_SYNCH_BEGIN_EVT:
		case NODE_FAILOVER_BEGIN_EVT:
		case NODE_FAILOVER_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case SELF_LEAVING_PEER_DOWN:
		switch (evt) {
		case SELF_LOST_CONTACT_EVT:
			state = SELF_DOWN_PEER_DOWN;
			break;
		case SELF_ESTABL_CONTACT_EVT:
		case PEER_ESTABL_CONTACT_EVT:
		case PEER_LOST_CONTACT_EVT:
			break;
		case NODE_SYNCH_END_EVT:
		case NODE_SYNCH_BEGIN_EVT:
		case NODE_FAILOVER_BEGIN_EVT:
		case NODE_FAILOVER_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case NODE_FAILINGOVER:
		switch (evt) {
		case SELF_LOST_CONTACT_EVT:
			state = SELF_DOWN_PEER_LEAVING;
			break;
		case PEER_LOST_CONTACT_EVT:
			state = SELF_LEAVING_PEER_DOWN;
			break;
		case NODE_FAILOVER_END_EVT:
			state = SELF_UP_PEER_UP;
			break;
		case NODE_FAILOVER_BEGIN_EVT:
		case SELF_ESTABL_CONTACT_EVT:
		case PEER_ESTABL_CONTACT_EVT:
			break;
		case NODE_SYNCH_BEGIN_EVT:
		case NODE_SYNCH_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case NODE_SYNCHING:
		switch (evt) {
		case SELF_LOST_CONTACT_EVT:
			state = SELF_DOWN_PEER_LEAVING;
			break;
		case PEER_LOST_CONTACT_EVT:
			state = SELF_LEAVING_PEER_DOWN;
			break;
		case NODE_SYNCH_END_EVT:
			state = SELF_UP_PEER_UP;
			break;
		case NODE_FAILOVER_BEGIN_EVT:
			state = NODE_FAILINGOVER;
			break;
		case NODE_SYNCH_BEGIN_EVT:
		case SELF_ESTABL_CONTACT_EVT:
		case PEER_ESTABL_CONTACT_EVT:
			break;
		case NODE_FAILOVER_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	default:
		pr_err("Unknown node fsm state %x\n", state);
		break;
	}
	n->state = state;
	return;

illegal_evt:
	pr_err("Illegal node fsm evt %x in state %x\n", evt, state);
}

bool tipc_node_filter_pkt(struct tipc_node *n, struct tipc_msg *hdr)
{
	int state = n->state;

	if (likely(state == SELF_UP_PEER_UP))
		return true;

	if (state == SELF_LEAVING_PEER_DOWN)
		return false;

	if (state == SELF_DOWN_PEER_LEAVING) {
		if (msg_peer_node_is_up(hdr))
			return false;
	}

	return true;
}

static void node_lost_contact(struct tipc_node *n,
			      struct sk_buff_head *inputq)
{
	char addr_string[16];
	struct tipc_sock_conn *conn, *safe;
	struct tipc_link *l;
	struct list_head *conns = &n->conn_sks;
	struct sk_buff *skb;
	uint i;

	pr_debug("Lost contact with %s\n",
		 tipc_addr_string_fill(addr_string, n->addr));

	/* Clean up broadcast state */
	tipc_bcast_remove_peer(n->net, n->bc_entry.link);

	/* Abort any ongoing link failover */
	for (i = 0; i < MAX_BEARERS; i++) {
		l = n->links[i].link;
		if (l)
			tipc_link_fsm_evt(l, LINK_FAILOVER_END_EVT);
	}

	/* Notify publications from this node */
	n->action_flags |= TIPC_NOTIFY_NODE_DOWN;

	/* Notify sockets connected to node */
	list_for_each_entry_safe(conn, safe, conns, list) {
		skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
				      SHORT_H_SIZE, 0, tipc_own_addr(n->net),
				      conn->peer_node, conn->port,
				      conn->peer_port, TIPC_ERR_NO_NODE);
		if (likely(skb))
			skb_queue_tail(inputq, skb);
		list_del(&conn->list);
		kfree(conn);
	}
}

/**
 * tipc_node_get_linkname - get the name of a link
 *
 * @bearer_id: id of the bearer
 * @node: peer node address
 * @linkname: link name output buffer
 *
 * Returns 0 on success
 */
int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 addr,
			   char *linkname, size_t len)
{
	struct tipc_link *link;
	int err = -EINVAL;
	struct tipc_node *node = tipc_node_find(net, addr);

	if (!node)
		return err;

	if (bearer_id >= MAX_BEARERS)
		goto exit;

	tipc_node_lock(node);
	link = node->links[bearer_id].link;
	if (link) {
		strncpy(linkname, link->name, len);
		err = 0;
	}
exit:
	tipc_node_unlock(node);
	tipc_node_put(node);
	return err;
}

void tipc_node_unlock(struct tipc_node *node)
{
	struct net *net = node->net;
	u32 addr = 0;
	u32 flags = node->action_flags;
	u32 link_id = 0;
	struct list_head *publ_list;

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

	addr = node->addr;
	link_id = node->link_id;
	publ_list = &node->publ_list;

	node->action_flags &= ~(TIPC_NOTIFY_NODE_DOWN | TIPC_NOTIFY_NODE_UP |
				TIPC_NOTIFY_LINK_DOWN | TIPC_NOTIFY_LINK_UP);

	spin_unlock_bh(&node->lock);

	if (flags & TIPC_NOTIFY_NODE_DOWN)
		tipc_publ_notify(net, publ_list, addr);

	if (flags & TIPC_NOTIFY_NODE_UP)
		tipc_named_node_up(net, addr);

	if (flags & TIPC_NOTIFY_LINK_UP)
		tipc_nametbl_publish(net, TIPC_LINK_STATE, addr, addr,
				     TIPC_NODE_SCOPE, link_id, addr);

	if (flags & TIPC_NOTIFY_LINK_DOWN)
		tipc_nametbl_withdraw(net, TIPC_LINK_STATE, addr,
				      link_id, addr);

}

/* Caller should hold node lock for the passed node */
static int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
{
	void *hdr;
	struct nlattr *attrs;

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

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

	if (nla_put_u32(msg->skb, TIPC_NLA_NODE_ADDR, node->addr))
		goto attr_msg_full;
	if (tipc_node_is_up(node))
		if (nla_put_flag(msg->skb, TIPC_NLA_NODE_UP))
			goto attr_msg_full;

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

	return 0;

attr_msg_full:
	nla_nest_cancel(msg->skb, attrs);
msg_full:
	genlmsg_cancel(msg->skb, hdr);

	return -EMSGSIZE;
}

static struct tipc_link *tipc_node_select_link(struct tipc_node *n, int sel,
					       int *bearer_id,
					       struct tipc_media_addr **maddr)
{
	int id = n->active_links[sel & 1];

	if (unlikely(id < 0))
		return NULL;

	*bearer_id = id;
	*maddr = &n->links[id].maddr;
	return n->links[id].link;
}

/**
 * tipc_node_xmit() is the general link level function for message sending
 * @net: the applicable net namespace
 * @list: chain of buffers containing message
 * @dnode: address of destination node
 * @selector: a number used for deterministic link selection
 * Consumes the buffer chain, except when returning -ELINKCONG
 * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
 */
int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
		   u32 dnode, int selector)
{
	struct tipc_link *l = NULL;
	struct tipc_node *n;
	struct sk_buff_head xmitq;
	struct tipc_media_addr *maddr;
	int bearer_id;
	int rc = -EHOSTUNREACH;

	__skb_queue_head_init(&xmitq);
	n = tipc_node_find(net, dnode);
	if (likely(n)) {
		tipc_node_lock(n);
		l = tipc_node_select_link(n, selector, &bearer_id, &maddr);
		if (likely(l))
			rc = tipc_link_xmit(l, list, &xmitq);
		tipc_node_unlock(n);
		if (unlikely(rc == -ENOBUFS))
			tipc_node_link_down(n, bearer_id, false);
		tipc_node_put(n);
	}
	if (likely(!rc)) {
		tipc_bearer_xmit(net, bearer_id, &xmitq, maddr);
		return 0;
	}
	if (likely(in_own_node(net, dnode))) {
		tipc_sk_rcv(net, list);
		return 0;
	}
	return rc;
}

/* tipc_node_xmit_skb(): send single buffer to destination
 * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
 * messages, which will not be rejected
 * The only exception is datagram messages rerouted after secondary
 * lookup, which are rare and safe to dispose of anyway.
 * TODO: Return real return value, and let callers use
 * tipc_wait_for_sendpkt() where applicable
 */
int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
		       u32 selector)
{
	struct sk_buff_head head;
	int rc;

	skb_queue_head_init(&head);
	__skb_queue_tail(&head, skb);
	rc = tipc_node_xmit(net, &head, dnode, selector);
	if (rc == -ELINKCONG)
		kfree_skb(skb);
	return 0;
}

/**
 * tipc_node_bc_rcv - process TIPC broadcast packet arriving from off-node
 * @net: the applicable net namespace
 * @skb: TIPC packet
 * @bearer_id: id of bearer message arrived on
 *
 * Invoked with no locks held.
 */
static void tipc_node_bc_rcv(struct net *net, struct sk_buff *skb, int bearer_id)
{
	int rc;
	struct sk_buff_head xmitq;
	struct tipc_bclink_entry *be;
	struct tipc_link_entry *le;
	struct tipc_msg *hdr = buf_msg(skb);
	int usr = msg_user(hdr);
	u32 dnode = msg_destnode(hdr);
	struct tipc_node *n;

	__skb_queue_head_init(&xmitq);

	/* If NACK for other node, let rcv link for that node peek into it */
	if ((usr == BCAST_PROTOCOL) && (dnode != tipc_own_addr(net)))
		n = tipc_node_find(net, dnode);
	else
		n = tipc_node_find(net, msg_prevnode(hdr));
	if (!n) {
		kfree_skb(skb);
		return;
	}
	be = &n->bc_entry;
	le = &n->links[bearer_id];

	rc = tipc_bcast_rcv(net, be->link, skb);

	/* Broadcast link reset may happen at reassembly failure */
	if (rc & TIPC_LINK_DOWN_EVT)
		tipc_node_reset_links(n);

	/* Broadcast ACKs are sent on a unicast link */
	if (rc & TIPC_LINK_SND_BC_ACK) {
		tipc_node_lock(n);
		tipc_link_build_ack_msg(le->link, &xmitq);
		tipc_node_unlock(n);
	}

	if (!skb_queue_empty(&xmitq))
		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);

	/* Deliver. 'arrvq' is under inputq2's lock protection */
	if (!skb_queue_empty(&be->inputq1)) {
		spin_lock_bh(&be->inputq2.lock);
		spin_lock_bh(&be->inputq1.lock);
		skb_queue_splice_tail_init(&be->inputq1, &be->arrvq);
		spin_unlock_bh(&be->inputq1.lock);
		spin_unlock_bh(&be->inputq2.lock);
		tipc_sk_mcast_rcv(net, &be->arrvq, &be->inputq2);
	}
	tipc_node_put(n);
}

/**
 * tipc_node_check_state - check and if necessary update node state
 * @skb: TIPC packet
 * @bearer_id: identity of bearer delivering the packet
 * Returns true if state is ok, otherwise consumes buffer and returns false
 */
static bool tipc_node_check_state(struct tipc_node *n, struct sk_buff *skb,
				  int bearer_id, struct sk_buff_head *xmitq)
{
	struct tipc_msg *hdr = buf_msg(skb);
	int usr = msg_user(hdr);
	int mtyp = msg_type(hdr);
	u16 oseqno = msg_seqno(hdr);
	u16 iseqno = msg_seqno(msg_get_wrapped(hdr));
	u16 exp_pkts = msg_msgcnt(hdr);
	u16 rcv_nxt, syncpt, dlv_nxt;
	int state = n->state;
	struct tipc_link *l, *tnl, *pl = NULL;
	struct tipc_media_addr *maddr;
	int i, pb_id;

	l = n->links[bearer_id].link;
	if (!l)
		return false;
	rcv_nxt = l->rcv_nxt;


	if (likely((state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL)))
		return true;

	/* Find parallel link, if any */
	for (i = 0; i < MAX_BEARERS; i++) {
		if ((i != bearer_id) && n->links[i].link) {
			pl = n->links[i].link;
			break;
		}
	}

	/* Update node accesibility if applicable */
	if (state == SELF_UP_PEER_COMING) {
		if (!tipc_link_is_up(l))
			return true;
		if (!msg_peer_link_is_up(hdr))
			return true;
		tipc_node_fsm_evt(n, PEER_ESTABL_CONTACT_EVT);
	}

	if (state == SELF_DOWN_PEER_LEAVING) {
		if (msg_peer_node_is_up(hdr))
			return false;
		tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);
	}

	/* Ignore duplicate packets */
	if ((usr != LINK_PROTOCOL) && less(oseqno, rcv_nxt))
		return true;

	/* Initiate or update failover mode if applicable */
	if ((usr == TUNNEL_PROTOCOL) && (mtyp == FAILOVER_MSG)) {
		syncpt = oseqno + exp_pkts - 1;
		if (pl && tipc_link_is_up(pl)) {
			pb_id = pl->bearer_id;
			__tipc_node_link_down(n, &pb_id, xmitq, &maddr);
			tipc_skb_queue_splice_tail_init(pl->inputq, l->inputq);
		}
		/* If pkts arrive out of order, use lowest calculated syncpt */
		if (less(syncpt, n->sync_point))
			n->sync_point = syncpt;
	}

	/* Open parallel link when tunnel link reaches synch point */
	if ((n->state == NODE_FAILINGOVER) && tipc_link_is_up(l)) {
		if (!more(rcv_nxt, n->sync_point))
			return true;
		tipc_node_fsm_evt(n, NODE_FAILOVER_END_EVT);
		if (pl)
			tipc_link_fsm_evt(pl, LINK_FAILOVER_END_EVT);
		return true;
	}

	/* No synching needed if only one link */
	if (!pl || !tipc_link_is_up(pl))
		return true;

	/* Initiate synch mode if applicable */
	if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG) && (oseqno == 1)) {
		syncpt = iseqno + exp_pkts - 1;
		if (!tipc_link_is_up(l)) {
			tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
			__tipc_node_link_up(n, bearer_id, xmitq);
		}
		if (n->state == SELF_UP_PEER_UP) {
			n->sync_point = syncpt;
			tipc_link_fsm_evt(l, LINK_SYNCH_BEGIN_EVT);
			tipc_node_fsm_evt(n, NODE_SYNCH_BEGIN_EVT);
		}
		if (less(syncpt, n->sync_point))
			n->sync_point = syncpt;
	}

	/* Open tunnel link when parallel link reaches synch point */
	if ((n->state == NODE_SYNCHING) && tipc_link_is_synching(l)) {
		if (tipc_link_is_synching(l)) {
			tnl = l;
		} else {
			tnl = pl;
			pl = l;
		}
		dlv_nxt = pl->rcv_nxt - mod(skb_queue_len(pl->inputq));
		if (more(dlv_nxt, n->sync_point)) {
			tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
			tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
			return true;
		}
		if (l == pl)
			return true;
		if ((usr == TUNNEL_PROTOCOL) && (mtyp == SYNCH_MSG))
			return true;
		if (usr == LINK_PROTOCOL)
			return true;
		return false;
	}
	return true;
}

/**
 * tipc_rcv - process TIPC packets/messages arriving from off-node
 * @net: the applicable net namespace
 * @skb: TIPC packet
 * @bearer: pointer to bearer message arrived on
 *
 * Invoked with no locks held. Bearer pointer must point to a valid bearer
 * structure (i.e. cannot be NULL), but bearer can be inactive.
 */
void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
{
	struct sk_buff_head xmitq;
	struct tipc_node *n;
	struct tipc_msg *hdr = buf_msg(skb);
	int usr = msg_user(hdr);
	int bearer_id = b->identity;
	struct tipc_link_entry *le;
	u16 bc_ack = msg_bcast_ack(hdr);
	int rc = 0;

	__skb_queue_head_init(&xmitq);

	/* Ensure message is well-formed */
	if (unlikely(!tipc_msg_validate(skb)))
		goto discard;

	/* Handle arrival of discovery or broadcast packet */
	if (unlikely(msg_non_seq(hdr))) {
		if (unlikely(usr == LINK_CONFIG))
			return tipc_disc_rcv(net, skb, b);
		else
			return tipc_node_bc_rcv(net, skb, bearer_id);
	}

	/* Locate neighboring node that sent packet */
	n = tipc_node_find(net, msg_prevnode(hdr));
	if (unlikely(!n))
		goto discard;
	le = &n->links[bearer_id];

	/* Ensure broadcast reception is in synch with peer's send state */
	if (unlikely(usr == LINK_PROTOCOL))
		tipc_bcast_sync_rcv(net, n->bc_entry.link, hdr);
	else if (unlikely(n->bc_entry.link->acked != bc_ack))
		tipc_bcast_ack_rcv(net, n->bc_entry.link, bc_ack);

	tipc_node_lock(n);

	/* Is reception permitted at the moment ? */
	if (!tipc_node_filter_pkt(n, hdr))
		goto unlock;

	/* Check and if necessary update node state */
	if (likely(tipc_node_check_state(n, skb, bearer_id, &xmitq))) {
		rc = tipc_link_rcv(le->link, skb, &xmitq);
		skb = NULL;
	}
unlock:
	tipc_node_unlock(n);

	if (unlikely(rc & TIPC_LINK_UP_EVT))
		tipc_node_link_up(n, bearer_id, &xmitq);

	if (unlikely(rc & TIPC_LINK_DOWN_EVT))
		tipc_node_link_down(n, bearer_id, false);

	if (unlikely(!skb_queue_empty(&n->bc_entry.namedq)))
		tipc_named_rcv(net, &n->bc_entry.namedq);

	if (!skb_queue_empty(&le->inputq))
		tipc_sk_rcv(net, &le->inputq);

	if (!skb_queue_empty(&xmitq))
		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);

	tipc_node_put(n);
discard:
	kfree_skb(skb);
}

int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
	int err;
	struct net *net = sock_net(skb->sk);
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	int done = cb->args[0];
	int last_addr = cb->args[1];
	struct tipc_node *node;
	struct tipc_nl_msg msg;

	if (done)
		return 0;

	msg.skb = skb;
	msg.portid = NETLINK_CB(cb->skb).portid;
	msg.seq = cb->nlh->nlmsg_seq;

	rcu_read_lock();
	if (last_addr) {
		node = tipc_node_find(net, last_addr);
		if (!node) {
			rcu_read_unlock();
			/* We never set seq or call nl_dump_check_consistent()
			 * this means that setting prev_seq here will cause the
			 * consistence check to fail in the netlink callback
			 * handler. Resulting in the NLMSG_DONE message having
			 * the NLM_F_DUMP_INTR flag set if the node state
			 * changed while we released the lock.
			 */
			cb->prev_seq = 1;
			return -EPIPE;
		}
		tipc_node_put(node);
	}

	list_for_each_entry_rcu(node, &tn->node_list, list) {
		if (last_addr) {
			if (node->addr == last_addr)
				last_addr = 0;
			else
				continue;
		}

		tipc_node_lock(node);
		err = __tipc_nl_add_node(&msg, node);
		if (err) {
			last_addr = node->addr;
			tipc_node_unlock(node);
			goto out;
		}

		tipc_node_unlock(node);
	}
	done = 1;
out:
	cb->args[0] = done;
	cb->args[1] = last_addr;
	rcu_read_unlock();

	return skb->len;
}