summaryrefslogtreecommitdiffstats
path: root/net/tipc/node.c
blob: 01b1f077603e50284467f10b8a533bd075fe7c3c (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
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
/*
 * net/tipc/node.c: TIPC node management routines
 *
 * Copyright (c) 2000-2006, 2012-2016, 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 "monitor.h"
#include "discover.h"
#include "netlink.h"

#define INVALID_NODE_SIG	0x10000

/* Flags used to take different actions according to flag type
 * TIPC_NOTIFY_NODE_DOWN: notify node is down
 * TIPC_NOTIFY_NODE_UP: notify node is up
 * TIPC_DISTRIBUTE_NAME: publish or withdraw link state name type
 */
enum {
	TIPC_NOTIFY_NODE_DOWN		= (1 << 3),
	TIPC_NOTIFY_NODE_UP		= (1 << 4),
	TIPC_NOTIFY_LINK_UP		= (1 << 6),
	TIPC_NOTIFY_LINK_DOWN		= (1 << 7)
};

struct tipc_link_entry {
	struct tipc_link *link;
	spinlock_t lock; /* per link */
	u32 mtu;
	struct sk_buff_head inputq;
	struct tipc_media_addr maddr;
};

struct tipc_bclink_entry {
	struct tipc_link *link;
	struct sk_buff_head inputq1;
	struct sk_buff_head arrvq;
	struct sk_buff_head inputq2;
	struct sk_buff_head namedq;
};

/**
 * struct tipc_node - TIPC node structure
 * @addr: network address of node
 * @ref: reference counter to node object
 * @lock: rwlock governing access to structure
 * @net: the applicable net namespace
 * @hash: links to adjacent nodes in unsorted hash chain
 * @inputq: pointer to input queue containing messages for msg event
 * @namedq: pointer to name table input queue with name table messages
 * @active_links: bearer ids of active links, used as index into links[] array
 * @links: array containing references to all links to node
 * @action_flags: bit mask of different types of node actions
 * @state: connectivity state vs peer node
 * @sync_point: sequence number where synch/failover is finished
 * @list: links to adjacent nodes in sorted list of cluster's nodes
 * @working_links: number of working links to node (both active and standby)
 * @link_cnt: number of links to node
 * @capabilities: bitmap, indicating peer node's functional capabilities
 * @signature: node instance identifier
 * @link_id: local and remote bearer ids of changing link, if any
 * @publ_list: list of publications
 * @rcu: rcu struct for tipc_node
 */
struct tipc_node {
	u32 addr;
	struct kref kref;
	rwlock_t lock;
	struct net *net;
	struct hlist_node hash;
	int active_links[2];
	struct tipc_link_entry links[MAX_BEARERS];
	struct tipc_bclink_entry bc_entry;
	int action_flags;
	struct list_head list;
	int state;
	u16 sync_point;
	int link_cnt;
	u16 working_links;
	u16 capabilities;
	u32 signature;
	u32 link_id;
	struct list_head publ_list;
	struct list_head conn_sks;
	unsigned long keepalive_intv;
	struct timer_list timer;
	struct rcu_head rcu;
};

/* 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);
static struct tipc_node *tipc_node_find(struct net *net, u32 addr);
static void tipc_node_put(struct tipc_node *node);
static bool tipc_node_is_up(struct tipc_node *n);

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

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

	if (unlikely(bearer_id == INVALID_BEARER_ID))
		return NULL;

	return n->links[bearer_id].link;
}

int tipc_node_get_mtu(struct net *net, u32 addr, u32 sel)
{
	struct tipc_node *n;
	int bearer_id;
	unsigned int mtu = MAX_MSG_SIZE;

	n = tipc_node_find(net, addr);
	if (unlikely(!n))
		return mtu;

	bearer_id = n->active_links[sel & 1];
	if (likely(bearer_id != INVALID_BEARER_ID))
		mtu = n->links[bearer_id].mtu;
	tipc_node_put(n);
	return mtu;
}

u16 tipc_node_get_capabilities(struct net *net, u32 addr)
{
	struct tipc_node *n;
	u16 caps;

	n = tipc_node_find(net, addr);
	if (unlikely(!n))
		return TIPC_NODE_CAPABILITIES;
	caps = n->capabilities;
	tipc_node_put(n);
	return caps;
}

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

	kfree(n->bc_entry.link);
	kfree_rcu(n, rcu);
}

static 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
 */
static struct tipc_node *tipc_node_find(struct net *net, u32 addr)
{
	struct tipc_net *tn = tipc_net(net);
	struct tipc_node *node;
	unsigned int thash = tipc_hashfn(addr);

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

	rcu_read_lock();
	hlist_for_each_entry_rcu(node, &tn->node_htable[thash], hash) {
		if (node->addr != addr)
			continue;
		if (!kref_get_unless_zero(&node->kref))
			node = NULL;
		break;
	}
	rcu_read_unlock();
	return node;
}

static void tipc_node_read_lock(struct tipc_node *n)
{
	read_lock_bh(&n->lock);
}

static void tipc_node_read_unlock(struct tipc_node *n)
{
	read_unlock_bh(&n->lock);
}

static void tipc_node_write_lock(struct tipc_node *n)
{
	write_lock_bh(&n->lock);
}

static void tipc_node_write_unlock_fast(struct tipc_node *n)
{
	write_unlock_bh(&n->lock);
}

static void tipc_node_write_unlock(struct tipc_node *n)
{
	struct net *net = n->net;
	u32 addr = 0;
	u32 flags = n->action_flags;
	u32 link_id = 0;
	u32 bearer_id;
	struct list_head *publ_list;

	if (likely(!flags)) {
		write_unlock_bh(&n->lock);
		return;
	}

	addr = n->addr;
	link_id = n->link_id;
	bearer_id = link_id & 0xffff;
	publ_list = &n->publ_list;

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

	write_unlock_bh(&n->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_mon_peer_up(net, addr, bearer_id);
		tipc_nametbl_publish(net, TIPC_LINK_STATE, addr, addr,
				     TIPC_NODE_SCOPE, link_id, addr);
	}
	if (flags & TIPC_NOTIFY_LINK_DOWN) {
		tipc_mon_peer_down(net, addr, bearer_id);
		tipc_nametbl_withdraw(net, TIPC_LINK_STATE, addr,
				      link_id, addr);
	}
}

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, *temp_node;
	int i;

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

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

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

	/* Ensure link's abort limit corresponds to current tolerance */
	tipc_link_set_abort_limit(l, tol / n->keepalive_intv);
}

static void tipc_node_delete(struct tipc_node *node)
{
	list_del_rcu(&node->list);
	hlist_del_rcu(&node->hash);
	tipc_node_put(node);

	del_timer_sync(&node->timer);
	tipc_node_put(node);
}

void tipc_node_stop(struct net *net)
{
	struct tipc_net *tn = tipc_net(net);
	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)
		tipc_node_delete(node);
	spin_unlock_bh(&tn->node_list_lock);
}

void tipc_node_subscribe(struct net *net, struct list_head *subscr, u32 addr)
{
	struct tipc_node *n;

	if (in_own_node(net, addr))
		return;

	n = tipc_node_find(net, addr);
	if (!n) {
		pr_warn("Node subscribe rejected, unknown node 0x%x\n", addr);
		return;
	}
	tipc_node_write_lock(n);
	list_add_tail(subscr, &n->publ_list);
	tipc_node_write_unlock_fast(n);
	tipc_node_put(n);
}

void tipc_node_unsubscribe(struct net *net, struct list_head *subscr, u32 addr)
{
	struct tipc_node *n;

	if (in_own_node(net, addr))
		return;

	n = tipc_node_find(net, addr);
	if (!n) {
		pr_warn("Node unsubscribe rejected, unknown node 0x%x\n", addr);
		return;
	}
	tipc_node_write_lock(n);
	list_del_init(subscr);
	tipc_node_write_unlock_fast(n);
	tipc_node_put(n);
}

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_write_lock(node);
	list_add_tail(&conn->list, &node->conn_sks);
	tipc_node_write_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_write_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_write_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_read_lock(n);
		le = &n->links[bearer_id];
		spin_lock_bh(&le->lock);
		if (le->link) {
			/* Link tolerance may change asynchronously: */
			tipc_node_calculate_timer(n, le->link);
			rc = tipc_link_timeout(le->link, &xmitq);
		}
		spin_unlock_bh(&le->lock);
		tipc_node_read_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);
	}
	mod_timer(&n->timer, jiffies + msecs_to_jiffies(n->keepalive_intv));
}

/**
 * __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 || tipc_link_is_up(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 = tipc_link_id(nl);

	/* Leave room for tunnel header when returning 'mtu' to users: */
	n->links[bearer_id].mtu = tipc_link_mtu(nl) - 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",
		 tipc_link_name(nl), tipc_link_plane(nl));

	/* Ensure that a STATE message goes first */
	tipc_link_build_state_msg(nl, xmitq);

	/* 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_link_set_active(nl, true);
		tipc_bcast_add_peer(n->net, nl, xmitq);
		return;
	}

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

	/* 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)
{
	struct tipc_media_addr *maddr;

	tipc_node_write_lock(n);
	__tipc_node_link_up(n, bearer_id, xmitq);
	maddr = &n->links[bearer_id].maddr;
	tipc_bearer_xmit(n->net, bearer_id, xmitq, maddr);
	tipc_node_write_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, prio;
	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 = tipc_link_id(l);

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

	pr_debug("Lost link <%s> on network plane %c\n",
		 tipc_link_name(l), tipc_link_plane(l));

	/* 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;
		prio = tipc_link_prio(_l);
		if (prio < highest)
			continue;
		if (prio > highest) {
			highest = prio;
			*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 */
	*bearer_id = n->active_links[0];
	tnl = n->links[*bearer_id].link;
	tipc_link_fsm_evt(tnl, LINK_SYNCH_END_EVT);
	tipc_node_fsm_evt(n, NODE_SYNCH_END_EVT);
	n->sync_point = tipc_link_rcv_nxt(tnl) + (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[*bearer_id].maddr;
}

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;
	int old_bearer_id = bearer_id;

	if (!l)
		return;

	__skb_queue_head_init(&xmitq);

	tipc_node_write_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_write_unlock(n);
	if (delete)
		tipc_mon_remove_peer(n->net, n->addr, old_bearer_id);
	tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);
	tipc_sk_rcv(n->net, &le->inputq);
}

static 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;
	unsigned long intv;

	*dupl_addr = false;
	*respond = false;

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

	tipc_node_write_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) {
			intv = jiffies + msecs_to_jiffies(n->keepalive_intv);
			if (!mod_timer(&n->timer, intv))
				tipc_node_get(n);
		}
	}
	memcpy(&le->maddr, maddr, sizeof(*maddr));
exit:
	tipc_node_write_unlock(n);
	if (reset && l && !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_DOWN;
			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_DOWN_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);
}

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

/* 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;
}

/**
 * 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.
 * Returns 0 if success, otherwise: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE,-ENOBUF
 */
int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
		   u32 dnode, int selector)
{
	struct tipc_link_entry *le = NULL;
	struct tipc_node *n;
	struct sk_buff_head xmitq;
	int bearer_id;
	int rc;

	if (in_own_node(net, dnode)) {
		tipc_sk_rcv(net, list);
		return 0;
	}

	n = tipc_node_find(net, dnode);
	if (unlikely(!n)) {
		skb_queue_purge(list);
		return -EHOSTUNREACH;
	}

	tipc_node_read_lock(n);
	bearer_id = n->active_links[selector & 1];
	if (unlikely(bearer_id == INVALID_BEARER_ID)) {
		tipc_node_read_unlock(n);
		tipc_node_put(n);
		skb_queue_purge(list);
		return -EHOSTUNREACH;
	}

	__skb_queue_head_init(&xmitq);
	le = &n->links[bearer_id];
	spin_lock_bh(&le->lock);
	rc = tipc_link_xmit(le->link, list, &xmitq);
	spin_unlock_bh(&le->lock);
	tipc_node_read_unlock(n);

	if (unlikely(rc == -ENOBUFS))
		tipc_node_link_down(n, bearer_id, false);
	else
		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);

	tipc_node_put(n);

	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.
 */
int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
		       u32 selector)
{
	struct sk_buff_head head;

	skb_queue_head_init(&head);
	__skb_queue_tail(&head, skb);
	tipc_node_xmit(net, &head, dnode, selector);
	return 0;
}

void tipc_node_broadcast(struct net *net, struct sk_buff *skb)
{
	struct sk_buff *txskb;
	struct tipc_node *n;
	u32 dst;

	rcu_read_lock();
	list_for_each_entry_rcu(n, tipc_nodes(net), list) {
		dst = n->addr;
		if (in_own_node(net, dst))
			continue;
		if (!tipc_node_is_up(n))
			continue;
		txskb = pskb_copy(skb, GFP_ATOMIC);
		if (!txskb)
			break;
		msg_set_destnode(buf_msg(txskb), dst);
		tipc_node_xmit_skb(net, txskb, dst, 0);
	}
	rcu_read_unlock();

	kfree_skb(skb);
}

static void tipc_node_mcast_rcv(struct tipc_node *n)
{
	struct tipc_bclink_entry *be = &n->bc_entry;

	/* 'arrvq' is under inputq2's lock protection */
	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(n->net, &be->arrvq, &be->inputq2);
}

static void tipc_node_bc_sync_rcv(struct tipc_node *n, struct tipc_msg *hdr,
				  int bearer_id, struct sk_buff_head *xmitq)
{
	struct tipc_link *ucl;
	int rc;

	rc = tipc_bcast_sync_rcv(n->net, n->bc_entry.link, hdr);

	if (rc & TIPC_LINK_DOWN_EVT) {
		tipc_bearer_reset_all(n->net);
		return;
	}

	if (!(rc & TIPC_LINK_SND_STATE))
		return;

	/* If probe message, a STATE response will be sent anyway */
	if (msg_probe(hdr))
		return;

	/* Produce a STATE message carrying broadcast NACK */
	tipc_node_read_lock(n);
	ucl = n->links[bearer_id].link;
	if (ucl)
		tipc_link_build_state_msg(ucl, xmitq);
	tipc_node_read_unlock(n);
}

/**
 * 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 ACKs are sent on a unicast link */
	if (rc & TIPC_LINK_SND_STATE) {
		tipc_node_read_lock(n);
		tipc_link_build_state_msg(le->link, &xmitq);
		tipc_node_read_unlock(n);
	}

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

	if (!skb_queue_empty(&be->inputq1))
		tipc_node_mcast_rcv(n);

	if (rc & TIPC_LINK_DOWN_EVT) {
		/* Reception reassembly failure => reset all links to peer */
		if (!tipc_link_is_up(be->link))
			tipc_node_reset_links(n);

		/* Retransmission failure => reset all links to all peers */
		if (!tipc_link_is_up(tipc_bc_sndlink(net)))
			tipc_bearer_reset_all(net);
	}

	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, inputq_len;
	int state = n->state;
	struct tipc_link *l, *tnl, *pl = NULL;
	struct tipc_media_addr *maddr;
	int pb_id;

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


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

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

	/* Check and 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);
		return true;
	}

	if (state == SELF_LEAVING_PEER_DOWN)
		return false;

	/* 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)) {
			__tipc_node_link_down(n, &pb_id, xmitq, &maddr);
			tipc_skb_queue_splice_tail_init(tipc_link_inputq(pl),
							tipc_link_inputq(l));
		}
		/* 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);
		}
	}

	/* Open tunnel link when parallel link reaches synch point */
	if (n->state == NODE_SYNCHING) {
		if (tipc_link_is_synching(l)) {
			tnl = l;
		} else {
			tnl = pl;
			pl = l;
		}
		inputq_len = skb_queue_len(tipc_link_inputq(pl));
		dlv_nxt = tipc_link_rcv_nxt(pl) - inputq_len;
		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;
	int bearer_id = b->identity;
	struct tipc_link_entry *le;
	u32 self = tipc_own_addr(net);
	int usr, rc = 0;
	u16 bc_ack;

	__skb_queue_head_init(&xmitq);

	/* Ensure message is well-formed before touching the header */
	if (unlikely(!tipc_msg_validate(skb)))
		goto discard;
	hdr = buf_msg(skb);
	usr = msg_user(hdr);
	bc_ack = msg_bcast_ack(hdr);

	/* 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);
	}

	/* Discard unicast link messages destined for another node */
	if (unlikely(!msg_short(hdr) && (msg_destnode(hdr) != self)))
		goto discard;

	/* 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_node_bc_sync_rcv(n, hdr, bearer_id, &xmitq);
	else if (unlikely(tipc_link_acked(n->bc_entry.link) != bc_ack))
		tipc_bcast_ack_rcv(net, n->bc_entry.link, hdr);

	/* Receive packet directly if conditions permit */
	tipc_node_read_lock(n);
	if (likely((n->state == SELF_UP_PEER_UP) && (usr != TUNNEL_PROTOCOL))) {
		spin_lock_bh(&le->lock);
		if (le->link) {
			rc = tipc_link_rcv(le->link, skb, &xmitq);
			skb = NULL;
		}
		spin_unlock_bh(&le->lock);
	}
	tipc_node_read_unlock(n);

	/* Check/update node state before receiving */
	if (unlikely(skb)) {
		tipc_node_write_lock(n);
		if (tipc_node_check_state(n, skb, bearer_id, &xmitq)) {
			if (le->link) {
				rc = tipc_link_rcv(le->link, skb, &xmitq);
				skb = NULL;
			}
		}
		tipc_node_write_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 (unlikely(!skb_queue_empty(&n->bc_entry.inputq1)))
		tipc_node_mcast_rcv(n);

	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_peer_rm(struct sk_buff *skb, struct genl_info *info)
{
	struct net *net = sock_net(skb->sk);
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
	struct tipc_node *peer;
	u32 addr;
	int err;
	int i;

	/* We identify the peer by its net */
	if (!info->attrs[TIPC_NLA_NET])
		return -EINVAL;

	err = nla_parse_nested(attrs, TIPC_NLA_NET_MAX,
			       info->attrs[TIPC_NLA_NET], tipc_nl_net_policy,
			       info->extack);
	if (err)
		return err;

	if (!attrs[TIPC_NLA_NET_ADDR])
		return -EINVAL;

	addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);

	if (in_own_node(net, addr))
		return -ENOTSUPP;

	spin_lock_bh(&tn->node_list_lock);
	peer = tipc_node_find(net, addr);
	if (!peer) {
		spin_unlock_bh(&tn->node_list_lock);
		return -ENXIO;
	}

	tipc_node_write_lock(peer);
	if (peer->state != SELF_DOWN_PEER_DOWN &&
	    peer->state != SELF_DOWN_PEER_LEAVING) {
		tipc_node_write_unlock(peer);
		err = -EBUSY;
		goto err_out;
	}

	for (i = 0; i < MAX_BEARERS; i++) {
		struct tipc_link_entry *le = &peer->links[i];

		if (le->link) {
			kfree(le->link);
			le->link = NULL;
			peer->link_cnt--;
		}
	}
	tipc_node_write_unlock(peer);
	tipc_node_delete(peer);

	err = 0;
err_out:
	tipc_node_put(peer);
	spin_unlock_bh(&tn->node_list_lock);

	return err;
}

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

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

	return skb->len;
}

/* tipc_node_find_by_name - locate owner node of link by link's name
 * @net: the applicable net namespace
 * @name: pointer to link name string
 * @bearer_id: pointer to index in 'node->links' array where the link was found.
 *
 * Returns pointer to node owning the link, or 0 if no matching link is found.
 */
static struct tipc_node *tipc_node_find_by_name(struct net *net,
						const char *link_name,
						unsigned int *bearer_id)
{
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_link *l;
	struct tipc_node *n;
	struct tipc_node *found_node = NULL;
	int i;

	*bearer_id = 0;
	rcu_read_lock();
	list_for_each_entry_rcu(n, &tn->node_list, list) {
		tipc_node_read_lock(n);
		for (i = 0; i < MAX_BEARERS; i++) {
			l = n->links[i].link;
			if (l && !strcmp(tipc_link_name(l), link_name)) {
				*bearer_id = i;
				found_node = n;
				break;
			}
		}
		tipc_node_read_unlock(n);
		if (found_node)
			break;
	}
	rcu_read_unlock();

	return found_node;
}

int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info)
{
	int err;
	int res = 0;
	int bearer_id;
	char *name;
	struct tipc_link *link;
	struct tipc_node *node;
	struct sk_buff_head xmitq;
	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
	struct net *net = sock_net(skb->sk);

	__skb_queue_head_init(&xmitq);

	if (!info->attrs[TIPC_NLA_LINK])
		return -EINVAL;

	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
			       info->attrs[TIPC_NLA_LINK],
			       tipc_nl_link_policy, info->extack);
	if (err)
		return err;

	if (!attrs[TIPC_NLA_LINK_NAME])
		return -EINVAL;

	name = nla_data(attrs[TIPC_NLA_LINK_NAME]);

	if (strcmp(name, tipc_bclink_name) == 0)
		return tipc_nl_bc_link_set(net, attrs);

	node = tipc_node_find_by_name(net, name, &bearer_id);
	if (!node)
		return -EINVAL;

	tipc_node_read_lock(node);

	link = node->links[bearer_id].link;
	if (!link) {
		res = -EINVAL;
		goto out;
	}

	if (attrs[TIPC_NLA_LINK_PROP]) {
		struct nlattr *props[TIPC_NLA_PROP_MAX + 1];

		err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
					      props);
		if (err) {
			res = err;
			goto out;
		}

		if (props[TIPC_NLA_PROP_TOL]) {
			u32 tol;

			tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
			tipc_link_set_tolerance(link, tol, &xmitq);
		}
		if (props[TIPC_NLA_PROP_PRIO]) {
			u32 prio;

			prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
			tipc_link_set_prio(link, prio, &xmitq);
		}
		if (props[TIPC_NLA_PROP_WIN]) {
			u32 win;

			win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
			tipc_link_set_queue_limits(link, win);
		}
	}

out:
	tipc_node_read_unlock(node);
	tipc_bearer_xmit(net, bearer_id, &xmitq, &node->links[bearer_id].maddr);
	return res;
}

int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info)
{
	struct net *net = genl_info_net(info);
	struct tipc_nl_msg msg;
	char *name;
	int err;

	msg.portid = info->snd_portid;
	msg.seq = info->snd_seq;

	if (!info->attrs[TIPC_NLA_LINK_NAME])
		return -EINVAL;
	name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);

	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!msg.skb)
		return -ENOMEM;

	if (strcmp(name, tipc_bclink_name) == 0) {
		err = tipc_nl_add_bc_link(net, &msg);
		if (err) {
			nlmsg_free(msg.skb);
			return err;
		}
	} else {
		int bearer_id;
		struct tipc_node *node;
		struct tipc_link *link;

		node = tipc_node_find_by_name(net, name, &bearer_id);
		if (!node)
			return -EINVAL;

		tipc_node_read_lock(node);
		link = node->links[bearer_id].link;
		if (!link) {
			tipc_node_read_unlock(node);
			nlmsg_free(msg.skb);
			return -EINVAL;
		}

		err = __tipc_nl_add_link(net, &msg, link, 0);
		tipc_node_read_unlock(node);
		if (err) {
			nlmsg_free(msg.skb);
			return err;
		}
	}

	return genlmsg_reply(msg.skb, info);
}

int tipc_nl_node_reset_link_stats(struct sk_buff *skb, struct genl_info *info)
{
	int err;
	char *link_name;
	unsigned int bearer_id;
	struct tipc_link *link;
	struct tipc_node *node;
	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
	struct net *net = sock_net(skb->sk);
	struct tipc_link_entry *le;

	if (!info->attrs[TIPC_NLA_LINK])
		return -EINVAL;

	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
			       info->attrs[TIPC_NLA_LINK],
			       tipc_nl_link_policy, info->extack);
	if (err)
		return err;

	if (!attrs[TIPC_NLA_LINK_NAME])
		return -EINVAL;

	link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);

	if (strcmp(link_name, tipc_bclink_name) == 0) {
		err = tipc_bclink_reset_stats(net);
		if (err)
			return err;
		return 0;
	}

	node = tipc_node_find_by_name(net, link_name, &bearer_id);
	if (!node)
		return -EINVAL;

	le = &node->links[bearer_id];
	tipc_node_read_lock(node);
	spin_lock_bh(&le->lock);
	link = node->links[bearer_id].link;
	if (!link) {
		spin_unlock_bh(&le->lock);
		tipc_node_read_unlock(node);
		return -EINVAL;
	}
	tipc_link_reset_stats(link);
	spin_unlock_bh(&le->lock);
	tipc_node_read_unlock(node);
	return 0;
}

/* Caller should hold node lock  */
static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
				    struct tipc_node *node, u32 *prev_link)
{
	u32 i;
	int err;

	for (i = *prev_link; i < MAX_BEARERS; i++) {
		*prev_link = i;

		if (!node->links[i].link)
			continue;

		err = __tipc_nl_add_link(net, msg,
					 node->links[i].link, NLM_F_MULTI);
		if (err)
			return err;
	}
	*prev_link = 0;

	return 0;
}

int tipc_nl_node_dump_link(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct net *net = sock_net(skb->sk);
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	struct tipc_node *node;
	struct tipc_nl_msg msg;
	u32 prev_node = cb->args[0];
	u32 prev_link = cb->args[1];
	int done = cb->args[2];
	int err;

	if (done)
		return 0;

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

	rcu_read_lock();
	if (prev_node) {
		node = tipc_node_find(net, prev_node);
		if (!node) {
			/* 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 last NLMSG_DONE message
			 * having the NLM_F_DUMP_INTR flag set.
			 */
			cb->prev_seq = 1;
			goto out;
		}
		tipc_node_put(node);

		list_for_each_entry_continue_rcu(node, &tn->node_list,
						 list) {
			tipc_node_read_lock(node);
			err = __tipc_nl_add_node_links(net, &msg, node,
						       &prev_link);
			tipc_node_read_unlock(node);
			if (err)
				goto out;

			prev_node = node->addr;
		}
	} else {
		err = tipc_nl_add_bc_link(net, &msg);
		if (err)
			goto out;

		list_for_each_entry_rcu(node, &tn->node_list, list) {
			tipc_node_read_lock(node);
			err = __tipc_nl_add_node_links(net, &msg, node,
						       &prev_link);
			tipc_node_read_unlock(node);
			if (err)
				goto out;

			prev_node = node->addr;
		}
	}
	done = 1;
out:
	rcu_read_unlock();

	cb->args[0] = prev_node;
	cb->args[1] = prev_link;
	cb->args[2] = done;

	return skb->len;
}

int tipc_nl_node_set_monitor(struct sk_buff *skb, struct genl_info *info)
{
	struct nlattr *attrs[TIPC_NLA_MON_MAX + 1];
	struct net *net = sock_net(skb->sk);
	int err;

	if (!info->attrs[TIPC_NLA_MON])
		return -EINVAL;

	err = nla_parse_nested(attrs, TIPC_NLA_MON_MAX,
			       info->attrs[TIPC_NLA_MON],
			       tipc_nl_monitor_policy, info->extack);
	if (err)
		return err;

	if (attrs[TIPC_NLA_MON_ACTIVATION_THRESHOLD]) {
		u32 val;

		val = nla_get_u32(attrs[TIPC_NLA_MON_ACTIVATION_THRESHOLD]);
		err = tipc_nl_monitor_set_threshold(net, val);
		if (err)
			return err;
	}

	return 0;
}

static int __tipc_nl_add_monitor_prop(struct net *net, struct tipc_nl_msg *msg)
{
	struct nlattr *attrs;
	void *hdr;
	u32 val;

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

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

	val = tipc_nl_monitor_get_threshold(net);

	if (nla_put_u32(msg->skb, TIPC_NLA_MON_ACTIVATION_THRESHOLD, val))
		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;
}

int tipc_nl_node_get_monitor(struct sk_buff *skb, struct genl_info *info)
{
	struct net *net = sock_net(skb->sk);
	struct tipc_nl_msg msg;
	int err;

	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
	msg.portid = info->snd_portid;
	msg.seq = info->snd_seq;

	err = __tipc_nl_add_monitor_prop(net, &msg);
	if (err) {
		nlmsg_free(msg.skb);
		return err;
	}

	return genlmsg_reply(msg.skb, info);
}

int tipc_nl_node_dump_monitor(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct net *net = sock_net(skb->sk);
	u32 prev_bearer = cb->args[0];
	struct tipc_nl_msg msg;
	int err;
	int i;

	if (prev_bearer == MAX_BEARERS)
		return 0;

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

	rtnl_lock();
	for (i = prev_bearer; i < MAX_BEARERS; i++) {
		prev_bearer = i;
		err = __tipc_nl_add_monitor(net, &msg, prev_bearer);
		if (err)
			goto out;
	}

out:
	rtnl_unlock();
	cb->args[0] = prev_bearer;

	return skb->len;
}

int tipc_nl_node_dump_monitor_peer(struct sk_buff *skb,
				   struct netlink_callback *cb)
{
	struct net *net = sock_net(skb->sk);
	u32 prev_node = cb->args[1];
	u32 bearer_id = cb->args[2];
	int done = cb->args[0];
	struct tipc_nl_msg msg;
	int err;

	if (!prev_node) {
		struct nlattr **attrs;
		struct nlattr *mon[TIPC_NLA_MON_MAX + 1];

		err = tipc_nlmsg_parse(cb->nlh, &attrs);
		if (err)
			return err;

		if (!attrs[TIPC_NLA_MON])
			return -EINVAL;

		err = nla_parse_nested(mon, TIPC_NLA_MON_MAX,
				       attrs[TIPC_NLA_MON],
				       tipc_nl_monitor_policy, NULL);
		if (err)
			return err;

		if (!mon[TIPC_NLA_MON_REF])
			return -EINVAL;

		bearer_id = nla_get_u32(mon[TIPC_NLA_MON_REF]);

		if (bearer_id >= MAX_BEARERS)
			return -EINVAL;
	}

	if (done)
		return 0;

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

	rtnl_lock();
	err = tipc_nl_add_monitor_peer(net, &msg, bearer_id, &prev_node);
	if (!err)
		done = 1;

	rtnl_unlock();
	cb->args[0] = done;
	cb->args[1] = prev_node;
	cb->args[2] = bearer_id;

	return skb->len;
}