summaryrefslogtreecommitdiff
path: root/net/tipc/crypto.c
blob: 990a872cec46ebce6280b4cab6b6b44bd052da36 (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
// SPDX-License-Identifier: GPL-2.0
/**
 * net/tipc/crypto.c: TIPC crypto for key handling & packet en/decryption
 *
 * Copyright (c) 2019, Ericsson AB
 * 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 <crypto/aead.h>
#include <crypto/aes.h>
#include "crypto.h"

#define TIPC_TX_PROBE_LIM	msecs_to_jiffies(1000) /* > 1s */
#define TIPC_TX_LASTING_LIM	msecs_to_jiffies(120000) /* 2 mins */
#define TIPC_RX_ACTIVE_LIM	msecs_to_jiffies(3000) /* 3s */
#define TIPC_RX_PASSIVE_LIM	msecs_to_jiffies(180000) /* 3 mins */
#define TIPC_MAX_TFMS_DEF	10
#define TIPC_MAX_TFMS_LIM	1000

/**
 * TIPC Key ids
 */
enum {
	KEY_UNUSED = 0,
	KEY_MIN,
	KEY_1 = KEY_MIN,
	KEY_2,
	KEY_3,
	KEY_MAX = KEY_3,
};

/**
 * TIPC Crypto statistics
 */
enum {
	STAT_OK,
	STAT_NOK,
	STAT_ASYNC,
	STAT_ASYNC_OK,
	STAT_ASYNC_NOK,
	STAT_BADKEYS, /* tx only */
	STAT_BADMSGS = STAT_BADKEYS, /* rx only */
	STAT_NOKEYS,
	STAT_SWITCHES,

	MAX_STATS,
};

/* TIPC crypto statistics' header */
static const char *hstats[MAX_STATS] = {"ok", "nok", "async", "async_ok",
					"async_nok", "badmsgs", "nokeys",
					"switches"};

/* Max TFMs number per key */
int sysctl_tipc_max_tfms __read_mostly = TIPC_MAX_TFMS_DEF;

/**
 * struct tipc_key - TIPC keys' status indicator
 *
 *         7     6     5     4     3     2     1     0
 *      +-----+-----+-----+-----+-----+-----+-----+-----+
 * key: | (reserved)|passive idx| active idx|pending idx|
 *      +-----+-----+-----+-----+-----+-----+-----+-----+
 */
struct tipc_key {
#define KEY_BITS (2)
#define KEY_MASK ((1 << KEY_BITS) - 1)
	union {
		struct {
#if defined(__LITTLE_ENDIAN_BITFIELD)
			u8 pending:2,
			   active:2,
			   passive:2, /* rx only */
			   reserved:2;
#elif defined(__BIG_ENDIAN_BITFIELD)
			u8 reserved:2,
			   passive:2, /* rx only */
			   active:2,
			   pending:2;
#else
#error  "Please fix <asm/byteorder.h>"
#endif
		} __packed;
		u8 keys;
	};
};

/**
 * struct tipc_tfm - TIPC TFM structure to form a list of TFMs
 */
struct tipc_tfm {
	struct crypto_aead *tfm;
	struct list_head list;
};

/**
 * struct tipc_aead - TIPC AEAD key structure
 * @tfm_entry: per-cpu pointer to one entry in TFM list
 * @crypto: TIPC crypto owns this key
 * @cloned: reference to the source key in case cloning
 * @users: the number of the key users (TX/RX)
 * @salt: the key's SALT value
 * @authsize: authentication tag size (max = 16)
 * @mode: crypto mode is applied to the key
 * @hint[]: a hint for user key
 * @rcu: struct rcu_head
 * @seqno: the key seqno (cluster scope)
 * @refcnt: the key reference counter
 */
struct tipc_aead {
#define TIPC_AEAD_HINT_LEN (5)
	struct tipc_tfm * __percpu *tfm_entry;
	struct tipc_crypto *crypto;
	struct tipc_aead *cloned;
	atomic_t users;
	u32 salt;
	u8 authsize;
	u8 mode;
	char hint[TIPC_AEAD_HINT_LEN + 1];
	struct rcu_head rcu;

	atomic64_t seqno ____cacheline_aligned;
	refcount_t refcnt ____cacheline_aligned;

} ____cacheline_aligned;

/**
 * struct tipc_crypto_stats - TIPC Crypto statistics
 */
struct tipc_crypto_stats {
	unsigned int stat[MAX_STATS];
};

/**
 * struct tipc_crypto - TIPC TX/RX crypto structure
 * @net: struct net
 * @node: TIPC node (RX)
 * @aead: array of pointers to AEAD keys for encryption/decryption
 * @peer_rx_active: replicated peer RX active key index
 * @key: the key states
 * @working: the crypto is working or not
 * @stats: the crypto statistics
 * @sndnxt: the per-peer sndnxt (TX)
 * @timer1: general timer 1 (jiffies)
 * @timer2: general timer 1 (jiffies)
 * @lock: tipc_key lock
 */
struct tipc_crypto {
	struct net *net;
	struct tipc_node *node;
	struct tipc_aead __rcu *aead[KEY_MAX + 1]; /* key[0] is UNUSED */
	atomic_t peer_rx_active;
	struct tipc_key key;
	u8 working:1;
	struct tipc_crypto_stats __percpu *stats;

	atomic64_t sndnxt ____cacheline_aligned;
	unsigned long timer1;
	unsigned long timer2;
	spinlock_t lock; /* crypto lock */

} ____cacheline_aligned;

/* struct tipc_crypto_tx_ctx - TX context for callbacks */
struct tipc_crypto_tx_ctx {
	struct tipc_aead *aead;
	struct tipc_bearer *bearer;
	struct tipc_media_addr dst;
};

/* struct tipc_crypto_rx_ctx - RX context for callbacks */
struct tipc_crypto_rx_ctx {
	struct tipc_aead *aead;
	struct tipc_bearer *bearer;
};

static struct tipc_aead *tipc_aead_get(struct tipc_aead __rcu *aead);
static inline void tipc_aead_put(struct tipc_aead *aead);
static void tipc_aead_free(struct rcu_head *rp);
static int tipc_aead_users(struct tipc_aead __rcu *aead);
static void tipc_aead_users_inc(struct tipc_aead __rcu *aead, int lim);
static void tipc_aead_users_dec(struct tipc_aead __rcu *aead, int lim);
static void tipc_aead_users_set(struct tipc_aead __rcu *aead, int val);
static struct crypto_aead *tipc_aead_tfm_next(struct tipc_aead *aead);
static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
			  u8 mode);
static int tipc_aead_clone(struct tipc_aead **dst, struct tipc_aead *src);
static void *tipc_aead_mem_alloc(struct crypto_aead *tfm,
				 unsigned int crypto_ctx_size,
				 u8 **iv, struct aead_request **req,
				 struct scatterlist **sg, int nsg);
static int tipc_aead_encrypt(struct tipc_aead *aead, struct sk_buff *skb,
			     struct tipc_bearer *b,
			     struct tipc_media_addr *dst,
			     struct tipc_node *__dnode);
static void tipc_aead_encrypt_done(struct crypto_async_request *base, int err);
static int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead,
			     struct sk_buff *skb, struct tipc_bearer *b);
static void tipc_aead_decrypt_done(struct crypto_async_request *base, int err);
static inline int tipc_ehdr_size(struct tipc_ehdr *ehdr);
static int tipc_ehdr_build(struct net *net, struct tipc_aead *aead,
			   u8 tx_key, struct sk_buff *skb,
			   struct tipc_crypto *__rx);
static inline void tipc_crypto_key_set_state(struct tipc_crypto *c,
					     u8 new_passive,
					     u8 new_active,
					     u8 new_pending);
static int tipc_crypto_key_attach(struct tipc_crypto *c,
				  struct tipc_aead *aead, u8 pos);
static bool tipc_crypto_key_try_align(struct tipc_crypto *rx, u8 new_pending);
static struct tipc_aead *tipc_crypto_key_pick_tx(struct tipc_crypto *tx,
						 struct tipc_crypto *rx,
						 struct sk_buff *skb);
static void tipc_crypto_key_synch(struct tipc_crypto *rx, u8 new_rx_active,
				  struct tipc_msg *hdr);
static int tipc_crypto_key_revoke(struct net *net, u8 tx_key);
static void tipc_crypto_rcv_complete(struct net *net, struct tipc_aead *aead,
				     struct tipc_bearer *b,
				     struct sk_buff **skb, int err);
static void tipc_crypto_do_cmd(struct net *net, int cmd);
static char *tipc_crypto_key_dump(struct tipc_crypto *c, char *buf);
#ifdef TIPC_CRYPTO_DEBUG
static char *tipc_key_change_dump(struct tipc_key old, struct tipc_key new,
				  char *buf);
#endif

#define key_next(cur) ((cur) % KEY_MAX + 1)

#define tipc_aead_rcu_ptr(rcu_ptr, lock)				\
	rcu_dereference_protected((rcu_ptr), lockdep_is_held(lock))

#define tipc_aead_rcu_swap(rcu_ptr, ptr, lock)				\
	rcu_swap_protected((rcu_ptr), (ptr), lockdep_is_held(lock))

#define tipc_aead_rcu_replace(rcu_ptr, ptr, lock)			\
do {									\
	typeof(rcu_ptr) __tmp = rcu_dereference_protected((rcu_ptr),	\
						lockdep_is_held(lock));	\
	rcu_assign_pointer((rcu_ptr), (ptr));				\
	tipc_aead_put(__tmp);						\
} while (0)

#define tipc_crypto_key_detach(rcu_ptr, lock)				\
	tipc_aead_rcu_replace((rcu_ptr), NULL, lock)

/**
 * tipc_aead_key_validate - Validate a AEAD user key
 */
int tipc_aead_key_validate(struct tipc_aead_key *ukey)
{
	int keylen;

	/* Check if algorithm exists */
	if (unlikely(!crypto_has_alg(ukey->alg_name, 0, 0))) {
		pr_info("Not found cipher: \"%s\"!\n", ukey->alg_name);
		return -ENODEV;
	}

	/* Currently, we only support the "gcm(aes)" cipher algorithm */
	if (strcmp(ukey->alg_name, "gcm(aes)"))
		return -ENOTSUPP;

	/* Check if key size is correct */
	keylen = ukey->keylen - TIPC_AES_GCM_SALT_SIZE;
	if (unlikely(keylen != TIPC_AES_GCM_KEY_SIZE_128 &&
		     keylen != TIPC_AES_GCM_KEY_SIZE_192 &&
		     keylen != TIPC_AES_GCM_KEY_SIZE_256))
		return -EINVAL;

	return 0;
}

static struct tipc_aead *tipc_aead_get(struct tipc_aead __rcu *aead)
{
	struct tipc_aead *tmp;

	rcu_read_lock();
	tmp = rcu_dereference(aead);
	if (unlikely(!tmp || !refcount_inc_not_zero(&tmp->refcnt)))
		tmp = NULL;
	rcu_read_unlock();

	return tmp;
}

static inline void tipc_aead_put(struct tipc_aead *aead)
{
	if (aead && refcount_dec_and_test(&aead->refcnt))
		call_rcu(&aead->rcu, tipc_aead_free);
}

/**
 * tipc_aead_free - Release AEAD key incl. all the TFMs in the list
 * @rp: rcu head pointer
 */
static void tipc_aead_free(struct rcu_head *rp)
{
	struct tipc_aead *aead = container_of(rp, struct tipc_aead, rcu);
	struct tipc_tfm *tfm_entry, *head, *tmp;

	if (aead->cloned) {
		tipc_aead_put(aead->cloned);
	} else {
		head = *this_cpu_ptr(aead->tfm_entry);
		list_for_each_entry_safe(tfm_entry, tmp, &head->list, list) {
			crypto_free_aead(tfm_entry->tfm);
			list_del(&tfm_entry->list);
			kfree(tfm_entry);
		}
		/* Free the head */
		crypto_free_aead(head->tfm);
		list_del(&head->list);
		kfree(head);
	}
	free_percpu(aead->tfm_entry);
	kfree(aead);
}

static int tipc_aead_users(struct tipc_aead __rcu *aead)
{
	struct tipc_aead *tmp;
	int users = 0;

	rcu_read_lock();
	tmp = rcu_dereference(aead);
	if (tmp)
		users = atomic_read(&tmp->users);
	rcu_read_unlock();

	return users;
}

static void tipc_aead_users_inc(struct tipc_aead __rcu *aead, int lim)
{
	struct tipc_aead *tmp;

	rcu_read_lock();
	tmp = rcu_dereference(aead);
	if (tmp)
		atomic_add_unless(&tmp->users, 1, lim);
	rcu_read_unlock();
}

static void tipc_aead_users_dec(struct tipc_aead __rcu *aead, int lim)
{
	struct tipc_aead *tmp;

	rcu_read_lock();
	tmp = rcu_dereference(aead);
	if (tmp)
		atomic_add_unless(&rcu_dereference(aead)->users, -1, lim);
	rcu_read_unlock();
}

static void tipc_aead_users_set(struct tipc_aead __rcu *aead, int val)
{
	struct tipc_aead *tmp;
	int cur;

	rcu_read_lock();
	tmp = rcu_dereference(aead);
	if (tmp) {
		do {
			cur = atomic_read(&tmp->users);
			if (cur == val)
				break;
		} while (atomic_cmpxchg(&tmp->users, cur, val) != cur);
	}
	rcu_read_unlock();
}

/**
 * tipc_aead_tfm_next - Move TFM entry to the next one in list and return it
 */
static struct crypto_aead *tipc_aead_tfm_next(struct tipc_aead *aead)
{
	struct tipc_tfm **tfm_entry = this_cpu_ptr(aead->tfm_entry);

	*tfm_entry = list_next_entry(*tfm_entry, list);
	return (*tfm_entry)->tfm;
}

/**
 * tipc_aead_init - Initiate TIPC AEAD
 * @aead: returned new TIPC AEAD key handle pointer
 * @ukey: pointer to user key data
 * @mode: the key mode
 *
 * Allocate a (list of) new cipher transformation (TFM) with the specific user
 * key data if valid. The number of the allocated TFMs can be set via the sysfs
 * "net/tipc/max_tfms" first.
 * Also, all the other AEAD data are also initialized.
 *
 * Return: 0 if the initiation is successful, otherwise: < 0
 */
static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
			  u8 mode)
{
	struct tipc_tfm *tfm_entry, *head;
	struct crypto_aead *tfm;
	struct tipc_aead *tmp;
	int keylen, err, cpu;
	int tfm_cnt = 0;

	if (unlikely(*aead))
		return -EEXIST;

	/* Allocate a new AEAD */
	tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
	if (unlikely(!tmp))
		return -ENOMEM;

	/* The key consists of two parts: [AES-KEY][SALT] */
	keylen = ukey->keylen - TIPC_AES_GCM_SALT_SIZE;

	/* Allocate per-cpu TFM entry pointer */
	tmp->tfm_entry = alloc_percpu(struct tipc_tfm *);
	if (!tmp->tfm_entry) {
		kzfree(tmp);
		return -ENOMEM;
	}

	/* Make a list of TFMs with the user key data */
	do {
		tfm = crypto_alloc_aead(ukey->alg_name, 0, 0);
		if (IS_ERR(tfm)) {
			err = PTR_ERR(tfm);
			break;
		}

		if (unlikely(!tfm_cnt &&
			     crypto_aead_ivsize(tfm) != TIPC_AES_GCM_IV_SIZE)) {
			crypto_free_aead(tfm);
			err = -ENOTSUPP;
			break;
		}

		err = crypto_aead_setauthsize(tfm, TIPC_AES_GCM_TAG_SIZE);
		err |= crypto_aead_setkey(tfm, ukey->key, keylen);
		if (unlikely(err)) {
			crypto_free_aead(tfm);
			break;
		}

		tfm_entry = kmalloc(sizeof(*tfm_entry), GFP_KERNEL);
		if (unlikely(!tfm_entry)) {
			crypto_free_aead(tfm);
			err = -ENOMEM;
			break;
		}
		INIT_LIST_HEAD(&tfm_entry->list);
		tfm_entry->tfm = tfm;

		/* First entry? */
		if (!tfm_cnt) {
			head = tfm_entry;
			for_each_possible_cpu(cpu) {
				*per_cpu_ptr(tmp->tfm_entry, cpu) = head;
			}
		} else {
			list_add_tail(&tfm_entry->list, &head->list);
		}

	} while (++tfm_cnt < sysctl_tipc_max_tfms);

	/* Not any TFM is allocated? */
	if (!tfm_cnt) {
		free_percpu(tmp->tfm_entry);
		kzfree(tmp);
		return err;
	}

	/* Copy some chars from the user key as a hint */
	memcpy(tmp->hint, ukey->key, TIPC_AEAD_HINT_LEN);
	tmp->hint[TIPC_AEAD_HINT_LEN] = '\0';

	/* Initialize the other data */
	tmp->mode = mode;
	tmp->cloned = NULL;
	tmp->authsize = TIPC_AES_GCM_TAG_SIZE;
	memcpy(&tmp->salt, ukey->key + keylen, TIPC_AES_GCM_SALT_SIZE);
	atomic_set(&tmp->users, 0);
	atomic64_set(&tmp->seqno, 0);
	refcount_set(&tmp->refcnt, 1);

	*aead = tmp;
	return 0;
}

/**
 * tipc_aead_clone - Clone a TIPC AEAD key
 * @dst: dest key for the cloning
 * @src: source key to clone from
 *
 * Make a "copy" of the source AEAD key data to the dest, the TFMs list is
 * common for the keys.
 * A reference to the source is hold in the "cloned" pointer for the later
 * freeing purposes.
 *
 * Note: this must be done in cluster-key mode only!
 * Return: 0 in case of success, otherwise < 0
 */
static int tipc_aead_clone(struct tipc_aead **dst, struct tipc_aead *src)
{
	struct tipc_aead *aead;
	int cpu;

	if (!src)
		return -ENOKEY;

	if (src->mode != CLUSTER_KEY)
		return -EINVAL;

	if (unlikely(*dst))
		return -EEXIST;

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

	aead->tfm_entry = alloc_percpu_gfp(struct tipc_tfm *, GFP_ATOMIC);
	if (unlikely(!aead->tfm_entry)) {
		kzfree(aead);
		return -ENOMEM;
	}

	for_each_possible_cpu(cpu) {
		*per_cpu_ptr(aead->tfm_entry, cpu) =
				*per_cpu_ptr(src->tfm_entry, cpu);
	}

	memcpy(aead->hint, src->hint, sizeof(src->hint));
	aead->mode = src->mode;
	aead->salt = src->salt;
	aead->authsize = src->authsize;
	atomic_set(&aead->users, 0);
	atomic64_set(&aead->seqno, 0);
	refcount_set(&aead->refcnt, 1);

	WARN_ON(!refcount_inc_not_zero(&src->refcnt));
	aead->cloned = src;

	*dst = aead;
	return 0;
}

/**
 * tipc_aead_mem_alloc - Allocate memory for AEAD request operations
 * @tfm: cipher handle to be registered with the request
 * @crypto_ctx_size: size of crypto context for callback
 * @iv: returned pointer to IV data
 * @req: returned pointer to AEAD request data
 * @sg: returned pointer to SG lists
 * @nsg: number of SG lists to be allocated
 *
 * Allocate memory to store the crypto context data, AEAD request, IV and SG
 * lists, the memory layout is as follows:
 * crypto_ctx || iv || aead_req || sg[]
 *
 * Return: the pointer to the memory areas in case of success, otherwise NULL
 */
static void *tipc_aead_mem_alloc(struct crypto_aead *tfm,
				 unsigned int crypto_ctx_size,
				 u8 **iv, struct aead_request **req,
				 struct scatterlist **sg, int nsg)
{
	unsigned int iv_size, req_size;
	unsigned int len;
	u8 *mem;

	iv_size = crypto_aead_ivsize(tfm);
	req_size = sizeof(**req) + crypto_aead_reqsize(tfm);

	len = crypto_ctx_size;
	len += iv_size;
	len += crypto_aead_alignmask(tfm) & ~(crypto_tfm_ctx_alignment() - 1);
	len = ALIGN(len, crypto_tfm_ctx_alignment());
	len += req_size;
	len = ALIGN(len, __alignof__(struct scatterlist));
	len += nsg * sizeof(**sg);

	mem = kmalloc(len, GFP_ATOMIC);
	if (!mem)
		return NULL;

	*iv = (u8 *)PTR_ALIGN(mem + crypto_ctx_size,
			      crypto_aead_alignmask(tfm) + 1);
	*req = (struct aead_request *)PTR_ALIGN(*iv + iv_size,
						crypto_tfm_ctx_alignment());
	*sg = (struct scatterlist *)PTR_ALIGN((u8 *)*req + req_size,
					      __alignof__(struct scatterlist));

	return (void *)mem;
}

/**
 * tipc_aead_encrypt - Encrypt a message
 * @aead: TIPC AEAD key for the message encryption
 * @skb: the input/output skb
 * @b: TIPC bearer where the message will be delivered after the encryption
 * @dst: the destination media address
 * @__dnode: TIPC dest node if "known"
 *
 * Return:
 * 0                   : if the encryption has completed
 * -EINPROGRESS/-EBUSY : if a callback will be performed
 * < 0                 : the encryption has failed
 */
static int tipc_aead_encrypt(struct tipc_aead *aead, struct sk_buff *skb,
			     struct tipc_bearer *b,
			     struct tipc_media_addr *dst,
			     struct tipc_node *__dnode)
{
	struct crypto_aead *tfm = tipc_aead_tfm_next(aead);
	struct tipc_crypto_tx_ctx *tx_ctx;
	struct aead_request *req;
	struct sk_buff *trailer;
	struct scatterlist *sg;
	struct tipc_ehdr *ehdr;
	int ehsz, len, tailen, nsg, rc;
	void *ctx;
	u32 salt;
	u8 *iv;

	/* Make sure message len at least 4-byte aligned */
	len = ALIGN(skb->len, 4);
	tailen = len - skb->len + aead->authsize;

	/* Expand skb tail for authentication tag:
	 * As for simplicity, we'd have made sure skb having enough tailroom
	 * for authentication tag @skb allocation. Even when skb is nonlinear
	 * but there is no frag_list, it should be still fine!
	 * Otherwise, we must cow it to be a writable buffer with the tailroom.
	 */
#ifdef TIPC_CRYPTO_DEBUG
	SKB_LINEAR_ASSERT(skb);
	if (tailen > skb_tailroom(skb)) {
		pr_warn("TX: skb tailroom is not enough: %d, requires: %d\n",
			skb_tailroom(skb), tailen);
	}
#endif

	if (unlikely(!skb_cloned(skb) && tailen <= skb_tailroom(skb))) {
		nsg = 1;
		trailer = skb;
	} else {
		/* TODO: We could avoid skb_cow_data() if skb has no frag_list
		 * e.g. by skb_fill_page_desc() to add another page to the skb
		 * with the wanted tailen... However, page skbs look not often,
		 * so take it easy now!
		 * Cloned skbs e.g. from link_xmit() seems no choice though :(
		 */
		nsg = skb_cow_data(skb, tailen, &trailer);
		if (unlikely(nsg < 0)) {
			pr_err("TX: skb_cow_data() returned %d\n", nsg);
			return nsg;
		}
	}

	pskb_put(skb, trailer, tailen);

	/* Allocate memory for the AEAD operation */
	ctx = tipc_aead_mem_alloc(tfm, sizeof(*tx_ctx), &iv, &req, &sg, nsg);
	if (unlikely(!ctx))
		return -ENOMEM;
	TIPC_SKB_CB(skb)->crypto_ctx = ctx;

	/* Map skb to the sg lists */
	sg_init_table(sg, nsg);
	rc = skb_to_sgvec(skb, sg, 0, skb->len);
	if (unlikely(rc < 0)) {
		pr_err("TX: skb_to_sgvec() returned %d, nsg %d!\n", rc, nsg);
		goto exit;
	}

	/* Prepare IV: [SALT (4 octets)][SEQNO (8 octets)]
	 * In case we're in cluster-key mode, SALT is varied by xor-ing with
	 * the source address (or w0 of id), otherwise with the dest address
	 * if dest is known.
	 */
	ehdr = (struct tipc_ehdr *)skb->data;
	salt = aead->salt;
	if (aead->mode == CLUSTER_KEY)
		salt ^= ehdr->addr; /* __be32 */
	else if (__dnode)
		salt ^= tipc_node_get_addr(__dnode);
	memcpy(iv, &salt, 4);
	memcpy(iv + 4, (u8 *)&ehdr->seqno, 8);

	/* Prepare request */
	ehsz = tipc_ehdr_size(ehdr);
	aead_request_set_tfm(req, tfm);
	aead_request_set_ad(req, ehsz);
	aead_request_set_crypt(req, sg, sg, len - ehsz, iv);

	/* Set callback function & data */
	aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
				  tipc_aead_encrypt_done, skb);
	tx_ctx = (struct tipc_crypto_tx_ctx *)ctx;
	tx_ctx->aead = aead;
	tx_ctx->bearer = b;
	memcpy(&tx_ctx->dst, dst, sizeof(*dst));

	/* Hold bearer */
	if (unlikely(!tipc_bearer_hold(b))) {
		rc = -ENODEV;
		goto exit;
	}

	/* Now, do encrypt */
	rc = crypto_aead_encrypt(req);
	if (rc == -EINPROGRESS || rc == -EBUSY)
		return rc;

	tipc_bearer_put(b);

exit:
	kfree(ctx);
	TIPC_SKB_CB(skb)->crypto_ctx = NULL;
	return rc;
}

static void tipc_aead_encrypt_done(struct crypto_async_request *base, int err)
{
	struct sk_buff *skb = base->data;
	struct tipc_crypto_tx_ctx *tx_ctx = TIPC_SKB_CB(skb)->crypto_ctx;
	struct tipc_bearer *b = tx_ctx->bearer;
	struct tipc_aead *aead = tx_ctx->aead;
	struct tipc_crypto *tx = aead->crypto;
	struct net *net = tx->net;

	switch (err) {
	case 0:
		this_cpu_inc(tx->stats->stat[STAT_ASYNC_OK]);
		if (likely(test_bit(0, &b->up)))
			b->media->send_msg(net, skb, b, &tx_ctx->dst);
		else
			kfree_skb(skb);
		break;
	case -EINPROGRESS:
		return;
	default:
		this_cpu_inc(tx->stats->stat[STAT_ASYNC_NOK]);
		kfree_skb(skb);
		break;
	}

	kfree(tx_ctx);
	tipc_bearer_put(b);
	tipc_aead_put(aead);
}

/**
 * tipc_aead_decrypt - Decrypt an encrypted message
 * @net: struct net
 * @aead: TIPC AEAD for the message decryption
 * @skb: the input/output skb
 * @b: TIPC bearer where the message has been received
 *
 * Return:
 * 0                   : if the decryption has completed
 * -EINPROGRESS/-EBUSY : if a callback will be performed
 * < 0                 : the decryption has failed
 */
static int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead,
			     struct sk_buff *skb, struct tipc_bearer *b)
{
	struct tipc_crypto_rx_ctx *rx_ctx;
	struct aead_request *req;
	struct crypto_aead *tfm;
	struct sk_buff *unused;
	struct scatterlist *sg;
	struct tipc_ehdr *ehdr;
	int ehsz, nsg, rc;
	void *ctx;
	u32 salt;
	u8 *iv;

	if (unlikely(!aead))
		return -ENOKEY;

	/* Cow skb data if needed */
	if (likely(!skb_cloned(skb) &&
		   (!skb_is_nonlinear(skb) || !skb_has_frag_list(skb)))) {
		nsg = 1 + skb_shinfo(skb)->nr_frags;
	} else {
		nsg = skb_cow_data(skb, 0, &unused);
		if (unlikely(nsg < 0)) {
			pr_err("RX: skb_cow_data() returned %d\n", nsg);
			return nsg;
		}
	}

	/* Allocate memory for the AEAD operation */
	tfm = tipc_aead_tfm_next(aead);
	ctx = tipc_aead_mem_alloc(tfm, sizeof(*rx_ctx), &iv, &req, &sg, nsg);
	if (unlikely(!ctx))
		return -ENOMEM;
	TIPC_SKB_CB(skb)->crypto_ctx = ctx;

	/* Map skb to the sg lists */
	sg_init_table(sg, nsg);
	rc = skb_to_sgvec(skb, sg, 0, skb->len);
	if (unlikely(rc < 0)) {
		pr_err("RX: skb_to_sgvec() returned %d, nsg %d\n", rc, nsg);
		goto exit;
	}

	/* Reconstruct IV: */
	ehdr = (struct tipc_ehdr *)skb->data;
	salt = aead->salt;
	if (aead->mode == CLUSTER_KEY)
		salt ^= ehdr->addr; /* __be32 */
	else if (ehdr->destined)
		salt ^= tipc_own_addr(net);
	memcpy(iv, &salt, 4);
	memcpy(iv + 4, (u8 *)&ehdr->seqno, 8);

	/* Prepare request */
	ehsz = tipc_ehdr_size(ehdr);
	aead_request_set_tfm(req, tfm);
	aead_request_set_ad(req, ehsz);
	aead_request_set_crypt(req, sg, sg, skb->len - ehsz, iv);

	/* Set callback function & data */
	aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
				  tipc_aead_decrypt_done, skb);
	rx_ctx = (struct tipc_crypto_rx_ctx *)ctx;
	rx_ctx->aead = aead;
	rx_ctx->bearer = b;

	/* Hold bearer */
	if (unlikely(!tipc_bearer_hold(b))) {
		rc = -ENODEV;
		goto exit;
	}

	/* Now, do decrypt */
	rc = crypto_aead_decrypt(req);
	if (rc == -EINPROGRESS || rc == -EBUSY)
		return rc;

	tipc_bearer_put(b);

exit:
	kfree(ctx);
	TIPC_SKB_CB(skb)->crypto_ctx = NULL;
	return rc;
}

static void tipc_aead_decrypt_done(struct crypto_async_request *base, int err)
{
	struct sk_buff *skb = base->data;
	struct tipc_crypto_rx_ctx *rx_ctx = TIPC_SKB_CB(skb)->crypto_ctx;
	struct tipc_bearer *b = rx_ctx->bearer;
	struct tipc_aead *aead = rx_ctx->aead;
	struct tipc_crypto_stats __percpu *stats = aead->crypto->stats;
	struct net *net = aead->crypto->net;

	switch (err) {
	case 0:
		this_cpu_inc(stats->stat[STAT_ASYNC_OK]);
		break;
	case -EINPROGRESS:
		return;
	default:
		this_cpu_inc(stats->stat[STAT_ASYNC_NOK]);
		break;
	}

	kfree(rx_ctx);
	tipc_crypto_rcv_complete(net, aead, b, &skb, err);
	if (likely(skb)) {
		if (likely(test_bit(0, &b->up)))
			tipc_rcv(net, skb, b);
		else
			kfree_skb(skb);
	}

	tipc_bearer_put(b);
}

static inline int tipc_ehdr_size(struct tipc_ehdr *ehdr)
{
	return (ehdr->user != LINK_CONFIG) ? EHDR_SIZE : EHDR_CFG_SIZE;
}

/**
 * tipc_ehdr_validate - Validate an encryption message
 * @skb: the message buffer
 *
 * Returns "true" if this is a valid encryption message, otherwise "false"
 */
bool tipc_ehdr_validate(struct sk_buff *skb)
{
	struct tipc_ehdr *ehdr;
	int ehsz;

	if (unlikely(!pskb_may_pull(skb, EHDR_MIN_SIZE)))
		return false;

	ehdr = (struct tipc_ehdr *)skb->data;
	if (unlikely(ehdr->version != TIPC_EVERSION))
		return false;
	ehsz = tipc_ehdr_size(ehdr);
	if (unlikely(!pskb_may_pull(skb, ehsz)))
		return false;
	if (unlikely(skb->len <= ehsz + TIPC_AES_GCM_TAG_SIZE))
		return false;
	if (unlikely(!ehdr->tx_key))
		return false;

	return true;
}

/**
 * tipc_ehdr_build - Build TIPC encryption message header
 * @net: struct net
 * @aead: TX AEAD key to be used for the message encryption
 * @tx_key: key id used for the message encryption
 * @skb: input/output message skb
 * @__rx: RX crypto handle if dest is "known"
 *
 * Return: the header size if the building is successful, otherwise < 0
 */
static int tipc_ehdr_build(struct net *net, struct tipc_aead *aead,
			   u8 tx_key, struct sk_buff *skb,
			   struct tipc_crypto *__rx)
{
	struct tipc_msg *hdr = buf_msg(skb);
	struct tipc_ehdr *ehdr;
	u32 user = msg_user(hdr);
	u64 seqno;
	int ehsz;

	/* Make room for encryption header */
	ehsz = (user != LINK_CONFIG) ? EHDR_SIZE : EHDR_CFG_SIZE;
	WARN_ON(skb_headroom(skb) < ehsz);
	ehdr = (struct tipc_ehdr *)skb_push(skb, ehsz);

	/* Obtain a seqno first:
	 * Use the key seqno (= cluster wise) if dest is unknown or we're in
	 * cluster key mode, otherwise it's better for a per-peer seqno!
	 */
	if (!__rx || aead->mode == CLUSTER_KEY)
		seqno = atomic64_inc_return(&aead->seqno);
	else
		seqno = atomic64_inc_return(&__rx->sndnxt);

	/* Revoke the key if seqno is wrapped around */
	if (unlikely(!seqno))
		return tipc_crypto_key_revoke(net, tx_key);

	/* Word 1-2 */
	ehdr->seqno = cpu_to_be64(seqno);

	/* Words 0, 3- */
	ehdr->version = TIPC_EVERSION;
	ehdr->user = 0;
	ehdr->keepalive = 0;
	ehdr->tx_key = tx_key;
	ehdr->destined = (__rx) ? 1 : 0;
	ehdr->rx_key_active = (__rx) ? __rx->key.active : 0;
	ehdr->reserved_1 = 0;
	ehdr->reserved_2 = 0;

	switch (user) {
	case LINK_CONFIG:
		ehdr->user = LINK_CONFIG;
		memcpy(ehdr->id, tipc_own_id(net), NODE_ID_LEN);
		break;
	default:
		if (user == LINK_PROTOCOL && msg_type(hdr) == STATE_MSG) {
			ehdr->user = LINK_PROTOCOL;
			ehdr->keepalive = msg_is_keepalive(hdr);
		}
		ehdr->addr = hdr->hdr[3];
		break;
	}

	return ehsz;
}

static inline void tipc_crypto_key_set_state(struct tipc_crypto *c,
					     u8 new_passive,
					     u8 new_active,
					     u8 new_pending)
{
#ifdef TIPC_CRYPTO_DEBUG
	struct tipc_key old = c->key;
	char buf[32];
#endif

	c->key.keys = ((new_passive & KEY_MASK) << (KEY_BITS * 2)) |
		      ((new_active  & KEY_MASK) << (KEY_BITS)) |
		      ((new_pending & KEY_MASK));

#ifdef TIPC_CRYPTO_DEBUG
	pr_info("%s(%s): key changing %s ::%pS\n",
		(c->node) ? "RX" : "TX",
		(c->node) ? tipc_node_get_id_str(c->node) :
			    tipc_own_id_string(c->net),
		tipc_key_change_dump(old, c->key, buf),
		__builtin_return_address(0));
#endif
}

/**
 * tipc_crypto_key_init - Initiate a new user / AEAD key
 * @c: TIPC crypto to which new key is attached
 * @ukey: the user key
 * @mode: the key mode (CLUSTER_KEY or PER_NODE_KEY)
 *
 * A new TIPC AEAD key will be allocated and initiated with the specified user
 * key, then attached to the TIPC crypto.
 *
 * Return: new key id in case of success, otherwise: < 0
 */
int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
			 u8 mode)
{
	struct tipc_aead *aead = NULL;
	int rc = 0;

	/* Initiate with the new user key */
	rc = tipc_aead_init(&aead, ukey, mode);

	/* Attach it to the crypto */
	if (likely(!rc)) {
		rc = tipc_crypto_key_attach(c, aead, 0);
		if (rc < 0)
			tipc_aead_free(&aead->rcu);
	}

	pr_info("%s(%s): key initiating, rc %d!\n",
		(c->node) ? "RX" : "TX",
		(c->node) ? tipc_node_get_id_str(c->node) :
			    tipc_own_id_string(c->net),
		rc);

	return rc;
}

/**
 * tipc_crypto_key_attach - Attach a new AEAD key to TIPC crypto
 * @c: TIPC crypto to which the new AEAD key is attached
 * @aead: the new AEAD key pointer
 * @pos: desired slot in the crypto key array, = 0 if any!
 *
 * Return: new key id in case of success, otherwise: -EBUSY
 */
static int tipc_crypto_key_attach(struct tipc_crypto *c,
				  struct tipc_aead *aead, u8 pos)
{
	u8 new_pending, new_passive, new_key;
	struct tipc_key key;
	int rc = -EBUSY;

	spin_lock_bh(&c->lock);
	key = c->key;
	if (key.active && key.passive)
		goto exit;
	if (key.passive && !tipc_aead_users(c->aead[key.passive]))
		goto exit;
	if (key.pending) {
		if (pos)
			goto exit;
		if (tipc_aead_users(c->aead[key.pending]) > 0)
			goto exit;
		/* Replace it */
		new_pending = key.pending;
		new_passive = key.passive;
		new_key = new_pending;
	} else {
		if (pos) {
			if (key.active && pos != key_next(key.active)) {
				new_pending = key.pending;
				new_passive = pos;
				new_key = new_passive;
				goto attach;
			} else if (!key.active && !key.passive) {
				new_pending = pos;
				new_passive = key.passive;
				new_key = new_pending;
				goto attach;
			}
		}
		new_pending = key_next(key.active ?: key.passive);
		new_passive = key.passive;
		new_key = new_pending;
	}

attach:
	aead->crypto = c;
	tipc_crypto_key_set_state(c, new_passive, key.active, new_pending);
	tipc_aead_rcu_replace(c->aead[new_key], aead, &c->lock);

	c->working = 1;
	c->timer1 = jiffies;
	c->timer2 = jiffies;
	rc = new_key;

exit:
	spin_unlock_bh(&c->lock);
	return rc;
}

void tipc_crypto_key_flush(struct tipc_crypto *c)
{
	int k;

	spin_lock_bh(&c->lock);
	c->working = 0;
	tipc_crypto_key_set_state(c, 0, 0, 0);
	for (k = KEY_MIN; k <= KEY_MAX; k++)
		tipc_crypto_key_detach(c->aead[k], &c->lock);
	atomic_set(&c->peer_rx_active, 0);
	atomic64_set(&c->sndnxt, 0);
	spin_unlock_bh(&c->lock);
}

/**
 * tipc_crypto_key_try_align - Align RX keys if possible
 * @rx: RX crypto handle
 * @new_pending: new pending slot if aligned (= TX key from peer)
 *
 * Peer has used an unknown key slot, this only happens when peer has left and
 * rejoned, or we are newcomer.
 * That means, there must be no active key but a pending key at unaligned slot.
 * If so, we try to move the pending key to the new slot.
 * Note: A potential passive key can exist, it will be shifted correspondingly!
 *
 * Return: "true" if key is successfully aligned, otherwise "false"
 */
static bool tipc_crypto_key_try_align(struct tipc_crypto *rx, u8 new_pending)
{
	struct tipc_aead *tmp1, *tmp2 = NULL;
	struct tipc_key key;
	bool aligned = false;
	u8 new_passive = 0;
	int x;

	spin_lock(&rx->lock);
	key = rx->key;
	if (key.pending == new_pending) {
		aligned = true;
		goto exit;
	}
	if (key.active)
		goto exit;
	if (!key.pending)
		goto exit;
	if (tipc_aead_users(rx->aead[key.pending]) > 0)
		goto exit;

	/* Try to "isolate" this pending key first */
	tmp1 = tipc_aead_rcu_ptr(rx->aead[key.pending], &rx->lock);
	if (!refcount_dec_if_one(&tmp1->refcnt))
		goto exit;
	rcu_assign_pointer(rx->aead[key.pending], NULL);

	/* Move passive key if any */
	if (key.passive) {
		tipc_aead_rcu_swap(rx->aead[key.passive], tmp2, &rx->lock);
		x = (key.passive - key.pending + new_pending) % KEY_MAX;
		new_passive = (x <= 0) ? x + KEY_MAX : x;
	}

	/* Re-allocate the key(s) */
	tipc_crypto_key_set_state(rx, new_passive, 0, new_pending);
	rcu_assign_pointer(rx->aead[new_pending], tmp1);
	if (new_passive)
		rcu_assign_pointer(rx->aead[new_passive], tmp2);
	refcount_set(&tmp1->refcnt, 1);
	aligned = true;
	pr_info("RX(%s): key is aligned!\n", tipc_node_get_id_str(rx->node));

exit:
	spin_unlock(&rx->lock);
	return aligned;
}

/**
 * tipc_crypto_key_pick_tx - Pick one TX key for message decryption
 * @tx: TX crypto handle
 * @rx: RX crypto handle (can be NULL)
 * @skb: the message skb which will be decrypted later
 *
 * This function looks up the existing TX keys and pick one which is suitable
 * for the message decryption, that must be a cluster key and not used before
 * on the same message (i.e. recursive).
 *
 * Return: the TX AEAD key handle in case of success, otherwise NULL
 */
static struct tipc_aead *tipc_crypto_key_pick_tx(struct tipc_crypto *tx,
						 struct tipc_crypto *rx,
						 struct sk_buff *skb)
{
	struct tipc_skb_cb *skb_cb = TIPC_SKB_CB(skb);
	struct tipc_aead *aead = NULL;
	struct tipc_key key = tx->key;
	u8 k, i = 0;

	/* Initialize data if not yet */
	if (!skb_cb->tx_clone_deferred) {
		skb_cb->tx_clone_deferred = 1;
		memset(&skb_cb->tx_clone_ctx, 0, sizeof(skb_cb->tx_clone_ctx));
	}

	skb_cb->tx_clone_ctx.rx = rx;
	if (++skb_cb->tx_clone_ctx.recurs > 2)
		return NULL;

	/* Pick one TX key */
	spin_lock(&tx->lock);
	do {
		k = (i == 0) ? key.pending :
			((i == 1) ? key.active : key.passive);
		if (!k)
			continue;
		aead = tipc_aead_rcu_ptr(tx->aead[k], &tx->lock);
		if (!aead)
			continue;
		if (aead->mode != CLUSTER_KEY ||
		    aead == skb_cb->tx_clone_ctx.last) {
			aead = NULL;
			continue;
		}
		/* Ok, found one cluster key */
		skb_cb->tx_clone_ctx.last = aead;
		WARN_ON(skb->next);
		skb->next = skb_clone(skb, GFP_ATOMIC);
		if (unlikely(!skb->next))
			pr_warn("Failed to clone skb for next round if any\n");
		WARN_ON(!refcount_inc_not_zero(&aead->refcnt));
		break;
	} while (++i < 3);
	spin_unlock(&tx->lock);

	return aead;
}

/**
 * tipc_crypto_key_synch: Synch own key data according to peer key status
 * @rx: RX crypto handle
 * @new_rx_active: latest RX active key from peer
 * @hdr: TIPCv2 message
 *
 * This function updates the peer node related data as the peer RX active key
 * has changed, so the number of TX keys' users on this node are increased and
 * decreased correspondingly.
 *
 * The "per-peer" sndnxt is also reset when the peer key has switched.
 */
static void tipc_crypto_key_synch(struct tipc_crypto *rx, u8 new_rx_active,
				  struct tipc_msg *hdr)
{
	struct net *net = rx->net;
	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
	u8 cur_rx_active;

	/* TX might be even not ready yet */
	if (unlikely(!tx->key.active && !tx->key.pending))
		return;

	cur_rx_active = atomic_read(&rx->peer_rx_active);
	if (likely(cur_rx_active == new_rx_active))
		return;

	/* Make sure this message destined for this node */
	if (unlikely(msg_short(hdr) ||
		     msg_destnode(hdr) != tipc_own_addr(net)))
		return;

	/* Peer RX active key has changed, try to update owns' & TX users */
	if (atomic_cmpxchg(&rx->peer_rx_active,
			   cur_rx_active,
			   new_rx_active) == cur_rx_active) {
		if (new_rx_active)
			tipc_aead_users_inc(tx->aead[new_rx_active], INT_MAX);
		if (cur_rx_active)
			tipc_aead_users_dec(tx->aead[cur_rx_active], 0);

		atomic64_set(&rx->sndnxt, 0);
		/* Mark the point TX key users changed */
		tx->timer1 = jiffies;

#ifdef TIPC_CRYPTO_DEBUG
		pr_info("TX(%s): key users changed %d-- %d++, peer RX(%s)\n",
			tipc_own_id_string(net), cur_rx_active,
			new_rx_active, tipc_node_get_id_str(rx->node));
#endif
	}
}

static int tipc_crypto_key_revoke(struct net *net, u8 tx_key)
{
	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
	struct tipc_key key;

	spin_lock(&tx->lock);
	key = tx->key;
	WARN_ON(!key.active || tx_key != key.active);

	/* Free the active key */
	tipc_crypto_key_set_state(tx, key.passive, 0, key.pending);
	tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
	spin_unlock(&tx->lock);

	pr_warn("TX(%s): key is revoked!\n", tipc_own_id_string(net));
	return -EKEYREVOKED;
}

int tipc_crypto_start(struct tipc_crypto **crypto, struct net *net,
		      struct tipc_node *node)
{
	struct tipc_crypto *c;

	if (*crypto)
		return -EEXIST;

	/* Allocate crypto */
	c = kzalloc(sizeof(*c), GFP_ATOMIC);
	if (!c)
		return -ENOMEM;

	/* Allocate statistic structure */
	c->stats = alloc_percpu_gfp(struct tipc_crypto_stats, GFP_ATOMIC);
	if (!c->stats) {
		kzfree(c);
		return -ENOMEM;
	}

	c->working = 0;
	c->net = net;
	c->node = node;
	tipc_crypto_key_set_state(c, 0, 0, 0);
	atomic_set(&c->peer_rx_active, 0);
	atomic64_set(&c->sndnxt, 0);
	c->timer1 = jiffies;
	c->timer2 = jiffies;
	spin_lock_init(&c->lock);
	*crypto = c;

	return 0;
}

void tipc_crypto_stop(struct tipc_crypto **crypto)
{
	struct tipc_crypto *c, *tx, *rx;
	bool is_rx;
	u8 k;

	if (!*crypto)
		return;

	rcu_read_lock();
	/* RX stopping? => decrease TX key users if any */
	is_rx = !!((*crypto)->node);
	if (is_rx) {
		rx = *crypto;
		tx = tipc_net(rx->net)->crypto_tx;
		k = atomic_read(&rx->peer_rx_active);
		if (k) {
			tipc_aead_users_dec(tx->aead[k], 0);
			/* Mark the point TX key users changed */
			tx->timer1 = jiffies;
		}
	}

	/* Release AEAD keys */
	c = *crypto;
	for (k = KEY_MIN; k <= KEY_MAX; k++)
		tipc_aead_put(rcu_dereference(c->aead[k]));
	rcu_read_unlock();

	pr_warn("%s(%s) has been purged, node left!\n",
		(is_rx) ? "RX" : "TX",
		(is_rx) ? tipc_node_get_id_str((*crypto)->node) :
			  tipc_own_id_string((*crypto)->net));

	/* Free this crypto statistics */
	free_percpu(c->stats);

	*crypto = NULL;
	kzfree(c);
}

void tipc_crypto_timeout(struct tipc_crypto *rx)
{
	struct tipc_net *tn = tipc_net(rx->net);
	struct tipc_crypto *tx = tn->crypto_tx;
	struct tipc_key key;
	u8 new_pending, new_passive;
	int cmd;

	/* TX key activating:
	 * The pending key (users > 0) -> active
	 * The active key if any (users == 0) -> free
	 */
	spin_lock(&tx->lock);
	key = tx->key;
	if (key.active && tipc_aead_users(tx->aead[key.active]) > 0)
		goto s1;
	if (!key.pending || tipc_aead_users(tx->aead[key.pending]) <= 0)
		goto s1;
	if (time_before(jiffies, tx->timer1 + TIPC_TX_LASTING_LIM))
		goto s1;

	tipc_crypto_key_set_state(tx, key.passive, key.pending, 0);
	if (key.active)
		tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
	this_cpu_inc(tx->stats->stat[STAT_SWITCHES]);
	pr_info("TX(%s): key %d is activated!\n", tipc_own_id_string(tx->net),
		key.pending);

s1:
	spin_unlock(&tx->lock);

	/* RX key activating:
	 * The pending key (users > 0) -> active
	 * The active key if any -> passive, freed later
	 */
	spin_lock(&rx->lock);
	key = rx->key;
	if (!key.pending || tipc_aead_users(rx->aead[key.pending]) <= 0)
		goto s2;

	new_pending = (key.passive &&
		       !tipc_aead_users(rx->aead[key.passive])) ?
				       key.passive : 0;
	new_passive = (key.active) ?: ((new_pending) ? 0 : key.passive);
	tipc_crypto_key_set_state(rx, new_passive, key.pending, new_pending);
	this_cpu_inc(rx->stats->stat[STAT_SWITCHES]);
	pr_info("RX(%s): key %d is activated!\n",
		tipc_node_get_id_str(rx->node),	key.pending);
	goto s5;

s2:
	/* RX key "faulty" switching:
	 * The faulty pending key (users < -30) -> passive
	 * The passive key (users = 0) -> pending
	 * Note: This only happens after RX deactivated - s3!
	 */
	key = rx->key;
	if (!key.pending || tipc_aead_users(rx->aead[key.pending]) > -30)
		goto s3;
	if (!key.passive || tipc_aead_users(rx->aead[key.passive]) != 0)
		goto s3;

	new_pending = key.passive;
	new_passive = key.pending;
	tipc_crypto_key_set_state(rx, new_passive, key.active, new_pending);
	goto s5;

s3:
	/* RX key deactivating:
	 * The passive key if any -> pending
	 * The active key -> passive (users = 0) / pending
	 * The pending key if any -> passive (users = 0)
	 */
	key = rx->key;
	if (!key.active)
		goto s4;
	if (time_before(jiffies, rx->timer1 + TIPC_RX_ACTIVE_LIM))
		goto s4;

	new_pending = (key.passive) ?: key.active;
	new_passive = (key.passive) ? key.active : key.pending;
	tipc_aead_users_set(rx->aead[new_pending], 0);
	if (new_passive)
		tipc_aead_users_set(rx->aead[new_passive], 0);
	tipc_crypto_key_set_state(rx, new_passive, 0, new_pending);
	pr_info("RX(%s): key %d is deactivated!\n",
		tipc_node_get_id_str(rx->node), key.active);
	goto s5;

s4:
	/* RX key passive -> freed: */
	key = rx->key;
	if (!key.passive || !tipc_aead_users(rx->aead[key.passive]))
		goto s5;
	if (time_before(jiffies, rx->timer2 + TIPC_RX_PASSIVE_LIM))
		goto s5;

	tipc_crypto_key_set_state(rx, 0, key.active, key.pending);
	tipc_crypto_key_detach(rx->aead[key.passive], &rx->lock);
	pr_info("RX(%s): key %d is freed!\n", tipc_node_get_id_str(rx->node),
		key.passive);

s5:
	spin_unlock(&rx->lock);

	/* Limit max_tfms & do debug commands if needed */
	if (likely(sysctl_tipc_max_tfms <= TIPC_MAX_TFMS_LIM))
		return;

	cmd = sysctl_tipc_max_tfms;
	sysctl_tipc_max_tfms = TIPC_MAX_TFMS_DEF;
	tipc_crypto_do_cmd(rx->net, cmd);
}

/**
 * tipc_crypto_xmit - Build & encrypt TIPC message for xmit
 * @net: struct net
 * @skb: input/output message skb pointer
 * @b: bearer used for xmit later
 * @dst: destination media address
 * @__dnode: destination node for reference if any
 *
 * First, build an encryption message header on the top of the message, then
 * encrypt the original TIPC message by using the active or pending TX key.
 * If the encryption is successful, the encrypted skb is returned directly or
 * via the callback.
 * Otherwise, the skb is freed!
 *
 * Return:
 * 0                   : the encryption has succeeded (or no encryption)
 * -EINPROGRESS/-EBUSY : the encryption is ongoing, a callback will be made
 * -ENOKEK             : the encryption has failed due to no key
 * -EKEYREVOKED        : the encryption has failed due to key revoked
 * -ENOMEM             : the encryption has failed due to no memory
 * < 0                 : the encryption has failed due to other reasons
 */
int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
		     struct tipc_bearer *b, struct tipc_media_addr *dst,
		     struct tipc_node *__dnode)
{
	struct tipc_crypto *__rx = tipc_node_crypto_rx(__dnode);
	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
	struct tipc_crypto_stats __percpu *stats = tx->stats;
	struct tipc_key key = tx->key;
	struct tipc_aead *aead = NULL;
	struct sk_buff *probe;
	int rc = -ENOKEY;
	u8 tx_key;

	/* No encryption? */
	if (!tx->working)
		return 0;

	/* Try with the pending key if available and:
	 * 1) This is the only choice (i.e. no active key) or;
	 * 2) Peer has switched to this key (unicast only) or;
	 * 3) It is time to do a pending key probe;
	 */
	if (unlikely(key.pending)) {
		tx_key = key.pending;
		if (!key.active)
			goto encrypt;
		if (__rx && atomic_read(&__rx->peer_rx_active) == tx_key)
			goto encrypt;
		if (TIPC_SKB_CB(*skb)->probe)
			goto encrypt;
		if (!__rx &&
		    time_after(jiffies, tx->timer2 + TIPC_TX_PROBE_LIM)) {
			tx->timer2 = jiffies;
			probe = skb_clone(*skb, GFP_ATOMIC);
			if (probe) {
				TIPC_SKB_CB(probe)->probe = 1;
				tipc_crypto_xmit(net, &probe, b, dst, __dnode);
				if (probe)
					b->media->send_msg(net, probe, b, dst);
			}
		}
	}
	/* Else, use the active key if any */
	if (likely(key.active)) {
		tx_key = key.active;
		goto encrypt;
	}
	goto exit;

encrypt:
	aead = tipc_aead_get(tx->aead[tx_key]);
	if (unlikely(!aead))
		goto exit;
	rc = tipc_ehdr_build(net, aead, tx_key, *skb, __rx);
	if (likely(rc > 0))
		rc = tipc_aead_encrypt(aead, *skb, b, dst, __dnode);

exit:
	switch (rc) {
	case 0:
		this_cpu_inc(stats->stat[STAT_OK]);
		break;
	case -EINPROGRESS:
	case -EBUSY:
		this_cpu_inc(stats->stat[STAT_ASYNC]);
		*skb = NULL;
		return rc;
	default:
		this_cpu_inc(stats->stat[STAT_NOK]);
		if (rc == -ENOKEY)
			this_cpu_inc(stats->stat[STAT_NOKEYS]);
		else if (rc == -EKEYREVOKED)
			this_cpu_inc(stats->stat[STAT_BADKEYS]);
		kfree_skb(*skb);
		*skb = NULL;
		break;
	}

	tipc_aead_put(aead);
	return rc;
}

/**
 * tipc_crypto_rcv - Decrypt an encrypted TIPC message from peer
 * @net: struct net
 * @rx: RX crypto handle
 * @skb: input/output message skb pointer
 * @b: bearer where the message has been received
 *
 * If the decryption is successful, the decrypted skb is returned directly or
 * as the callback, the encryption header and auth tag will be trimed out
 * before forwarding to tipc_rcv() via the tipc_crypto_rcv_complete().
 * Otherwise, the skb will be freed!
 * Note: RX key(s) can be re-aligned, or in case of no key suitable, TX
 * cluster key(s) can be taken for decryption (- recursive).
 *
 * Return:
 * 0                   : the decryption has successfully completed
 * -EINPROGRESS/-EBUSY : the decryption is ongoing, a callback will be made
 * -ENOKEY             : the decryption has failed due to no key
 * -EBADMSG            : the decryption has failed due to bad message
 * -ENOMEM             : the decryption has failed due to no memory
 * < 0                 : the decryption has failed due to other reasons
 */
int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
		    struct sk_buff **skb, struct tipc_bearer *b)
{
	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
	struct tipc_crypto_stats __percpu *stats;
	struct tipc_aead *aead = NULL;
	struct tipc_key key;
	int rc = -ENOKEY;
	u8 tx_key = 0;

	/* New peer?
	 * Let's try with TX key (i.e. cluster mode) & verify the skb first!
	 */
	if (unlikely(!rx))
		goto pick_tx;

	/* Pick RX key according to TX key, three cases are possible:
	 * 1) The current active key (likely) or;
	 * 2) The pending (new or deactivated) key (if any) or;
	 * 3) The passive or old active key (i.e. users > 0);
	 */
	tx_key = ((struct tipc_ehdr *)(*skb)->data)->tx_key;
	key = rx->key;
	if (likely(tx_key == key.active))
		goto decrypt;
	if (tx_key == key.pending)
		goto decrypt;
	if (tx_key == key.passive) {
		rx->timer2 = jiffies;
		if (tipc_aead_users(rx->aead[key.passive]) > 0)
			goto decrypt;
	}

	/* Unknown key, let's try to align RX key(s) */
	if (tipc_crypto_key_try_align(rx, tx_key))
		goto decrypt;

pick_tx:
	/* No key suitable? Try to pick one from TX... */
	aead = tipc_crypto_key_pick_tx(tx, rx, *skb);
	if (aead)
		goto decrypt;
	goto exit;

decrypt:
	rcu_read_lock();
	if (!aead)
		aead = tipc_aead_get(rx->aead[tx_key]);
	rc = tipc_aead_decrypt(net, aead, *skb, b);
	rcu_read_unlock();

exit:
	stats = ((rx) ?: tx)->stats;
	switch (rc) {
	case 0:
		this_cpu_inc(stats->stat[STAT_OK]);
		break;
	case -EINPROGRESS:
	case -EBUSY:
		this_cpu_inc(stats->stat[STAT_ASYNC]);
		*skb = NULL;
		return rc;
	default:
		this_cpu_inc(stats->stat[STAT_NOK]);
		if (rc == -ENOKEY) {
			kfree_skb(*skb);
			*skb = NULL;
			if (rx)
				tipc_node_put(rx->node);
			this_cpu_inc(stats->stat[STAT_NOKEYS]);
			return rc;
		} else if (rc == -EBADMSG) {
			this_cpu_inc(stats->stat[STAT_BADMSGS]);
		}
		break;
	}

	tipc_crypto_rcv_complete(net, aead, b, skb, rc);
	return rc;
}

static void tipc_crypto_rcv_complete(struct net *net, struct tipc_aead *aead,
				     struct tipc_bearer *b,
				     struct sk_buff **skb, int err)
{
	struct tipc_skb_cb *skb_cb = TIPC_SKB_CB(*skb);
	struct tipc_crypto *rx = aead->crypto;
	struct tipc_aead *tmp = NULL;
	struct tipc_ehdr *ehdr;
	struct tipc_node *n;
	u8 rx_key_active;
	bool destined;

	/* Is this completed by TX? */
	if (unlikely(!rx->node)) {
		rx = skb_cb->tx_clone_ctx.rx;
#ifdef TIPC_CRYPTO_DEBUG
		pr_info("TX->RX(%s): err %d, aead %p, skb->next %p, flags %x\n",
			(rx) ? tipc_node_get_id_str(rx->node) : "-", err, aead,
			(*skb)->next, skb_cb->flags);
		pr_info("skb_cb [recurs %d, last %p], tx->aead [%p %p %p]\n",
			skb_cb->tx_clone_ctx.recurs, skb_cb->tx_clone_ctx.last,
			aead->crypto->aead[1], aead->crypto->aead[2],
			aead->crypto->aead[3]);
#endif
		if (unlikely(err)) {
			if (err == -EBADMSG && (*skb)->next)
				tipc_rcv(net, (*skb)->next, b);
			goto free_skb;
		}

		if (likely((*skb)->next)) {
			kfree_skb((*skb)->next);
			(*skb)->next = NULL;
		}
		ehdr = (struct tipc_ehdr *)(*skb)->data;
		if (!rx) {
			WARN_ON(ehdr->user != LINK_CONFIG);
			n = tipc_node_create(net, 0, ehdr->id, 0xffffu, 0,
					     true);
			rx = tipc_node_crypto_rx(n);
			if (unlikely(!rx))
				goto free_skb;
		}

		/* Skip cloning this time as we had a RX pending key */
		if (rx->key.pending)
			goto rcv;
		if (tipc_aead_clone(&tmp, aead) < 0)
			goto rcv;
		if (tipc_crypto_key_attach(rx, tmp, ehdr->tx_key) < 0) {
			tipc_aead_free(&tmp->rcu);
			goto rcv;
		}
		tipc_aead_put(aead);
		aead = tipc_aead_get(tmp);
	}

	if (unlikely(err)) {
		tipc_aead_users_dec(aead, INT_MIN);
		goto free_skb;
	}

	/* Set the RX key's user */
	tipc_aead_users_set(aead, 1);

rcv:
	/* Mark this point, RX works */
	rx->timer1 = jiffies;

	/* Remove ehdr & auth. tag prior to tipc_rcv() */
	ehdr = (struct tipc_ehdr *)(*skb)->data;
	destined = ehdr->destined;
	rx_key_active = ehdr->rx_key_active;
	skb_pull(*skb, tipc_ehdr_size(ehdr));
	pskb_trim(*skb, (*skb)->len - aead->authsize);

	/* Validate TIPCv2 message */
	if (unlikely(!tipc_msg_validate(skb))) {
		pr_err_ratelimited("Packet dropped after decryption!\n");
		goto free_skb;
	}

	/* Update peer RX active key & TX users */
	if (destined)
		tipc_crypto_key_synch(rx, rx_key_active, buf_msg(*skb));

	/* Mark skb decrypted */
	skb_cb->decrypted = 1;

	/* Clear clone cxt if any */
	if (likely(!skb_cb->tx_clone_deferred))
		goto exit;
	skb_cb->tx_clone_deferred = 0;
	memset(&skb_cb->tx_clone_ctx, 0, sizeof(skb_cb->tx_clone_ctx));
	goto exit;

free_skb:
	kfree_skb(*skb);
	*skb = NULL;

exit:
	tipc_aead_put(aead);
	if (rx)
		tipc_node_put(rx->node);
}

static void tipc_crypto_do_cmd(struct net *net, int cmd)
{
	struct tipc_net *tn = tipc_net(net);
	struct tipc_crypto *tx = tn->crypto_tx, *rx;
	struct list_head *p;
	unsigned int stat;
	int i, j, cpu;
	char buf[200];

	/* Currently only one command is supported */
	switch (cmd) {
	case 0xfff1:
		goto print_stats;
	default:
		return;
	}

print_stats:
	/* Print a header */
	pr_info("\n=============== TIPC Crypto Statistics ===============\n\n");

	/* Print key status */
	pr_info("Key status:\n");
	pr_info("TX(%7.7s)\n%s", tipc_own_id_string(net),
		tipc_crypto_key_dump(tx, buf));

	rcu_read_lock();
	for (p = tn->node_list.next; p != &tn->node_list; p = p->next) {
		rx = tipc_node_crypto_rx_by_list(p);
		pr_info("RX(%7.7s)\n%s", tipc_node_get_id_str(rx->node),
			tipc_crypto_key_dump(rx, buf));
	}
	rcu_read_unlock();

	/* Print crypto statistics */
	for (i = 0, j = 0; i < MAX_STATS; i++)
		j += scnprintf(buf + j, 200 - j, "|%11s ", hstats[i]);
	pr_info("\nCounter     %s", buf);

	memset(buf, '-', 115);
	buf[115] = '\0';
	pr_info("%s\n", buf);

	j = scnprintf(buf, 200, "TX(%7.7s) ", tipc_own_id_string(net));
	for_each_possible_cpu(cpu) {
		for (i = 0; i < MAX_STATS; i++) {
			stat = per_cpu_ptr(tx->stats, cpu)->stat[i];
			j += scnprintf(buf + j, 200 - j, "|%11d ", stat);
		}
		pr_info("%s", buf);
		j = scnprintf(buf, 200, "%12s", " ");
	}

	rcu_read_lock();
	for (p = tn->node_list.next; p != &tn->node_list; p = p->next) {
		rx = tipc_node_crypto_rx_by_list(p);
		j = scnprintf(buf, 200, "RX(%7.7s) ",
			      tipc_node_get_id_str(rx->node));
		for_each_possible_cpu(cpu) {
			for (i = 0; i < MAX_STATS; i++) {
				stat = per_cpu_ptr(rx->stats, cpu)->stat[i];
				j += scnprintf(buf + j, 200 - j, "|%11d ",
					       stat);
			}
			pr_info("%s", buf);
			j = scnprintf(buf, 200, "%12s", " ");
		}
	}
	rcu_read_unlock();

	pr_info("\n======================== Done ========================\n");
}

static char *tipc_crypto_key_dump(struct tipc_crypto *c, char *buf)
{
	struct tipc_key key = c->key;
	struct tipc_aead *aead;
	int k, i = 0;
	char *s;

	for (k = KEY_MIN; k <= KEY_MAX; k++) {
		if (k == key.passive)
			s = "PAS";
		else if (k == key.active)
			s = "ACT";
		else if (k == key.pending)
			s = "PEN";
		else
			s = "-";
		i += scnprintf(buf + i, 200 - i, "\tKey%d: %s", k, s);

		rcu_read_lock();
		aead = rcu_dereference(c->aead[k]);
		if (aead)
			i += scnprintf(buf + i, 200 - i,
				       "{\"%s...\", \"%s\"}/%d:%d",
				       aead->hint,
				       (aead->mode == CLUSTER_KEY) ? "c" : "p",
				       atomic_read(&aead->users),
				       refcount_read(&aead->refcnt));
		rcu_read_unlock();
		i += scnprintf(buf + i, 200 - i, "\n");
	}

	if (c->node)
		i += scnprintf(buf + i, 200 - i, "\tPeer RX active: %d\n",
			       atomic_read(&c->peer_rx_active));

	return buf;
}

#ifdef TIPC_CRYPTO_DEBUG
static char *tipc_key_change_dump(struct tipc_key old, struct tipc_key new,
				  char *buf)
{
	struct tipc_key *key = &old;
	int k, i = 0;
	char *s;

	/* Output format: "[%s %s %s] -> [%s %s %s]", max len = 32 */
again:
	i += scnprintf(buf + i, 32 - i, "[");
	for (k = KEY_MIN; k <= KEY_MAX; k++) {
		if (k == key->passive)
			s = "pas";
		else if (k == key->active)
			s = "act";
		else if (k == key->pending)
			s = "pen";
		else
			s = "-";
		i += scnprintf(buf + i, 32 - i,
			       (k != KEY_MAX) ? "%s " : "%s", s);
	}
	if (key != &new) {
		i += scnprintf(buf + i, 32 - i, "] -> ");
		key = &new;
		goto again;
	}
	i += scnprintf(buf + i, 32 - i, "]");
	return buf;
}
#endif