summaryrefslogtreecommitdiff
path: root/net/can/bcm.c
blob: 9393f25df08d3fce299aaa463efd79244e6527e9 (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
/*
 * bcm.c - Broadcast Manager to filter/send (cyclic) CAN content
 *
 * Copyright (c) 2002-2017 Volkswagen Group Electronic Research
 * 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 name of Volkswagen nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * Alternatively, provided that this notice is retained in full, this
 * software may be distributed under the terms of the GNU General
 * Public License ("GPL") version 2, in which case the provisions of the
 * GPL apply INSTEAD OF those given above.
 *
 * The provided data structures and external interfaces from this code
 * are not restricted to be used by modules with a GPL compatible license.
 *
 * 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 <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/hrtimer.h>
#include <linux/list.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/uio.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/socket.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/can.h>
#include <linux/can/core.h>
#include <linux/can/skb.h>
#include <linux/can/bcm.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/net_namespace.h>

/*
 * To send multiple CAN frame content within TX_SETUP or to filter
 * CAN messages with multiplex index within RX_SETUP, the number of
 * different filters is limited to 256 due to the one byte index value.
 */
#define MAX_NFRAMES 256

/* use of last_frames[index].flags */
#define RX_RECV    0x40 /* received data for this element */
#define RX_THR     0x80 /* element not been sent due to throttle feature */
#define BCM_CAN_FLAGS_MASK 0x3F /* to clean private flags after usage */

/* get best masking value for can_rx_register() for a given single can_id */
#define REGMASK(id) ((id & CAN_EFF_FLAG) ? \
		     (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
		     (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))

#define CAN_BCM_VERSION "20170425"

MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
MODULE_ALIAS("can-proto-2");

/*
 * easy access to the first 64 bit of can(fd)_frame payload. cp->data is
 * 64 bit aligned so the offset has to be multiples of 8 which is ensured
 * by the only callers in bcm_rx_cmp_to_index() bcm_rx_handler().
 */
static inline u64 get_u64(const struct canfd_frame *cp, int offset)
{
	return *(u64 *)(cp->data + offset);
}

struct bcm_op {
	struct list_head list;
	int ifindex;
	canid_t can_id;
	u32 flags;
	unsigned long frames_abs, frames_filtered;
	struct bcm_timeval ival1, ival2;
	struct hrtimer timer, thrtimer;
	struct tasklet_struct tsklet, thrtsklet;
	ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg;
	int rx_ifindex;
	int cfsiz;
	u32 count;
	u32 nframes;
	u32 currframe;
	/* void pointers to arrays of struct can[fd]_frame */
	void *frames;
	void *last_frames;
	struct canfd_frame sframe;
	struct canfd_frame last_sframe;
	struct sock *sk;
	struct net_device *rx_reg_dev;
};

struct bcm_sock {
	struct sock sk;
	int bound;
	int ifindex;
	struct notifier_block notifier;
	struct list_head rx_ops;
	struct list_head tx_ops;
	unsigned long dropped_usr_msgs;
	struct proc_dir_entry *bcm_proc_read;
	char procname [32]; /* inode number in decimal with \0 */
};

static inline struct bcm_sock *bcm_sk(const struct sock *sk)
{
	return (struct bcm_sock *)sk;
}

static inline ktime_t bcm_timeval_to_ktime(struct bcm_timeval tv)
{
	return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
}

#define CFSIZ(flags) ((flags & CAN_FD_FRAME) ? CANFD_MTU : CAN_MTU)
#define OPSIZ sizeof(struct bcm_op)
#define MHSIZ sizeof(struct bcm_msg_head)

/*
 * procfs functions
 */
#if IS_ENABLED(CONFIG_PROC_FS)
static char *bcm_proc_getifname(struct net *net, char *result, int ifindex)
{
	struct net_device *dev;

	if (!ifindex)
		return "any";

	rcu_read_lock();
	dev = dev_get_by_index_rcu(net, ifindex);
	if (dev)
		strcpy(result, dev->name);
	else
		strcpy(result, "???");
	rcu_read_unlock();

	return result;
}

static int bcm_proc_show(struct seq_file *m, void *v)
{
	char ifname[IFNAMSIZ];
	struct net *net = m->private;
	struct sock *sk = (struct sock *)PDE_DATA(m->file->f_inode);
	struct bcm_sock *bo = bcm_sk(sk);
	struct bcm_op *op;

	seq_printf(m, ">>> socket %pK", sk->sk_socket);
	seq_printf(m, " / sk %pK", sk);
	seq_printf(m, " / bo %pK", bo);
	seq_printf(m, " / dropped %lu", bo->dropped_usr_msgs);
	seq_printf(m, " / bound %s", bcm_proc_getifname(net, ifname, bo->ifindex));
	seq_printf(m, " <<<\n");

	list_for_each_entry(op, &bo->rx_ops, list) {

		unsigned long reduction;

		/* print only active entries & prevent division by zero */
		if (!op->frames_abs)
			continue;

		seq_printf(m, "rx_op: %03X %-5s ", op->can_id,
			   bcm_proc_getifname(net, ifname, op->ifindex));

		if (op->flags & CAN_FD_FRAME)
			seq_printf(m, "(%u)", op->nframes);
		else
			seq_printf(m, "[%u]", op->nframes);

		seq_printf(m, "%c ", (op->flags & RX_CHECK_DLC) ? 'd' : ' ');

		if (op->kt_ival1)
			seq_printf(m, "timeo=%lld ",
				   (long long)ktime_to_us(op->kt_ival1));

		if (op->kt_ival2)
			seq_printf(m, "thr=%lld ",
				   (long long)ktime_to_us(op->kt_ival2));

		seq_printf(m, "# recv %ld (%ld) => reduction: ",
			   op->frames_filtered, op->frames_abs);

		reduction = 100 - (op->frames_filtered * 100) / op->frames_abs;

		seq_printf(m, "%s%ld%%\n",
			   (reduction == 100) ? "near " : "", reduction);
	}

	list_for_each_entry(op, &bo->tx_ops, list) {

		seq_printf(m, "tx_op: %03X %s ", op->can_id,
			   bcm_proc_getifname(net, ifname, op->ifindex));

		if (op->flags & CAN_FD_FRAME)
			seq_printf(m, "(%u) ", op->nframes);
		else
			seq_printf(m, "[%u] ", op->nframes);

		if (op->kt_ival1)
			seq_printf(m, "t1=%lld ",
				   (long long)ktime_to_us(op->kt_ival1));

		if (op->kt_ival2)
			seq_printf(m, "t2=%lld ",
				   (long long)ktime_to_us(op->kt_ival2));

		seq_printf(m, "# sent %ld\n", op->frames_abs);
	}
	seq_putc(m, '\n');
	return 0;
}
#endif /* CONFIG_PROC_FS */

/*
 * bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface
 *              of the given bcm tx op
 */
static void bcm_can_tx(struct bcm_op *op)
{
	struct sk_buff *skb;
	struct net_device *dev;
	struct canfd_frame *cf = op->frames + op->cfsiz * op->currframe;

	/* no target device? => exit */
	if (!op->ifindex)
		return;

	dev = dev_get_by_index(sock_net(op->sk), op->ifindex);
	if (!dev) {
		/* RFC: should this bcm_op remove itself here? */
		return;
	}

	skb = alloc_skb(op->cfsiz + sizeof(struct can_skb_priv), gfp_any());
	if (!skb)
		goto out;

	can_skb_reserve(skb);
	can_skb_prv(skb)->ifindex = dev->ifindex;
	can_skb_prv(skb)->skbcnt = 0;

	skb_put_data(skb, cf, op->cfsiz);

	/* send with loopback */
	skb->dev = dev;
	can_skb_set_owner(skb, op->sk);
	can_send(skb, 1);

	/* update statistics */
	op->currframe++;
	op->frames_abs++;

	/* reached last frame? */
	if (op->currframe >= op->nframes)
		op->currframe = 0;
out:
	dev_put(dev);
}

/*
 * bcm_send_to_user - send a BCM message to the userspace
 *                    (consisting of bcm_msg_head + x CAN frames)
 */
static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
			     struct canfd_frame *frames, int has_timestamp)
{
	struct sk_buff *skb;
	struct canfd_frame *firstframe;
	struct sockaddr_can *addr;
	struct sock *sk = op->sk;
	unsigned int datalen = head->nframes * op->cfsiz;
	int err;

	skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
	if (!skb)
		return;

	skb_put_data(skb, head, sizeof(*head));

	if (head->nframes) {
		/* CAN frames starting here */
		firstframe = (struct canfd_frame *)skb_tail_pointer(skb);

		skb_put_data(skb, frames, datalen);

		/*
		 * the BCM uses the flags-element of the canfd_frame
		 * structure for internal purposes. This is only
		 * relevant for updates that are generated by the
		 * BCM, where nframes is 1
		 */
		if (head->nframes == 1)
			firstframe->flags &= BCM_CAN_FLAGS_MASK;
	}

	if (has_timestamp) {
		/* restore rx timestamp */
		skb->tstamp = op->rx_stamp;
	}

	/*
	 *  Put the datagram to the queue so that bcm_recvmsg() can
	 *  get it from there.  We need to pass the interface index to
	 *  bcm_recvmsg().  We pass a whole struct sockaddr_can in skb->cb
	 *  containing the interface index.
	 */

	sock_skb_cb_check_size(sizeof(struct sockaddr_can));
	addr = (struct sockaddr_can *)skb->cb;
	memset(addr, 0, sizeof(*addr));
	addr->can_family  = AF_CAN;
	addr->can_ifindex = op->rx_ifindex;

	err = sock_queue_rcv_skb(sk, skb);
	if (err < 0) {
		struct bcm_sock *bo = bcm_sk(sk);

		kfree_skb(skb);
		/* don't care about overflows in this statistic */
		bo->dropped_usr_msgs++;
	}
}

static void bcm_tx_start_timer(struct bcm_op *op)
{
	if (op->kt_ival1 && op->count)
		hrtimer_start(&op->timer,
			      ktime_add(ktime_get(), op->kt_ival1),
			      HRTIMER_MODE_ABS);
	else if (op->kt_ival2)
		hrtimer_start(&op->timer,
			      ktime_add(ktime_get(), op->kt_ival2),
			      HRTIMER_MODE_ABS);
}

static void bcm_tx_timeout_tsklet(unsigned long data)
{
	struct bcm_op *op = (struct bcm_op *)data;
	struct bcm_msg_head msg_head;

	if (op->kt_ival1 && (op->count > 0)) {

		op->count--;
		if (!op->count && (op->flags & TX_COUNTEVT)) {

			/* create notification to user */
			msg_head.opcode  = TX_EXPIRED;
			msg_head.flags   = op->flags;
			msg_head.count   = op->count;
			msg_head.ival1   = op->ival1;
			msg_head.ival2   = op->ival2;
			msg_head.can_id  = op->can_id;
			msg_head.nframes = 0;

			bcm_send_to_user(op, &msg_head, NULL, 0);
		}
		bcm_can_tx(op);

	} else if (op->kt_ival2)
		bcm_can_tx(op);

	bcm_tx_start_timer(op);
}

/*
 * bcm_tx_timeout_handler - performs cyclic CAN frame transmissions
 */
static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
{
	struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);

	tasklet_schedule(&op->tsklet);

	return HRTIMER_NORESTART;
}

/*
 * bcm_rx_changed - create a RX_CHANGED notification due to changed content
 */
static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
{
	struct bcm_msg_head head;

	/* update statistics */
	op->frames_filtered++;

	/* prevent statistics overflow */
	if (op->frames_filtered > ULONG_MAX/100)
		op->frames_filtered = op->frames_abs = 0;

	/* this element is not throttled anymore */
	data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);

	head.opcode  = RX_CHANGED;
	head.flags   = op->flags;
	head.count   = op->count;
	head.ival1   = op->ival1;
	head.ival2   = op->ival2;
	head.can_id  = op->can_id;
	head.nframes = 1;

	bcm_send_to_user(op, &head, data, 1);
}

/*
 * bcm_rx_update_and_send - process a detected relevant receive content change
 *                          1. update the last received data
 *                          2. send a notification to the user (if possible)
 */
static void bcm_rx_update_and_send(struct bcm_op *op,
				   struct canfd_frame *lastdata,
				   const struct canfd_frame *rxdata)
{
	memcpy(lastdata, rxdata, op->cfsiz);

	/* mark as used and throttled by default */
	lastdata->flags |= (RX_RECV|RX_THR);

	/* throttling mode inactive ? */
	if (!op->kt_ival2) {
		/* send RX_CHANGED to the user immediately */
		bcm_rx_changed(op, lastdata);
		return;
	}

	/* with active throttling timer we are just done here */
	if (hrtimer_active(&op->thrtimer))
		return;

	/* first reception with enabled throttling mode */
	if (!op->kt_lastmsg)
		goto rx_changed_settime;

	/* got a second frame inside a potential throttle period? */
	if (ktime_us_delta(ktime_get(), op->kt_lastmsg) <
	    ktime_to_us(op->kt_ival2)) {
		/* do not send the saved data - only start throttle timer */
		hrtimer_start(&op->thrtimer,
			      ktime_add(op->kt_lastmsg, op->kt_ival2),
			      HRTIMER_MODE_ABS);
		return;
	}

	/* the gap was that big, that throttling was not needed here */
rx_changed_settime:
	bcm_rx_changed(op, lastdata);
	op->kt_lastmsg = ktime_get();
}

/*
 * bcm_rx_cmp_to_index - (bit)compares the currently received data to formerly
 *                       received data stored in op->last_frames[]
 */
static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
				const struct canfd_frame *rxdata)
{
	struct canfd_frame *cf = op->frames + op->cfsiz * index;
	struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
	int i;

	/*
	 * no one uses the MSBs of flags for comparison,
	 * so we use it here to detect the first time of reception
	 */

	if (!(lcf->flags & RX_RECV)) {
		/* received data for the first time => send update to user */
		bcm_rx_update_and_send(op, lcf, rxdata);
		return;
	}

	/* do a real check in CAN frame data section */
	for (i = 0; i < rxdata->len; i += 8) {
		if ((get_u64(cf, i) & get_u64(rxdata, i)) !=
		    (get_u64(cf, i) & get_u64(lcf, i))) {
			bcm_rx_update_and_send(op, lcf, rxdata);
			return;
		}
	}

	if (op->flags & RX_CHECK_DLC) {
		/* do a real check in CAN frame length */
		if (rxdata->len != lcf->len) {
			bcm_rx_update_and_send(op, lcf, rxdata);
			return;
		}
	}
}

/*
 * bcm_rx_starttimer - enable timeout monitoring for CAN frame reception
 */
static void bcm_rx_starttimer(struct bcm_op *op)
{
	if (op->flags & RX_NO_AUTOTIMER)
		return;

	if (op->kt_ival1)
		hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL);
}

static void bcm_rx_timeout_tsklet(unsigned long data)
{
	struct bcm_op *op = (struct bcm_op *)data;
	struct bcm_msg_head msg_head;

	/* create notification to user */
	msg_head.opcode  = RX_TIMEOUT;
	msg_head.flags   = op->flags;
	msg_head.count   = op->count;
	msg_head.ival1   = op->ival1;
	msg_head.ival2   = op->ival2;
	msg_head.can_id  = op->can_id;
	msg_head.nframes = 0;

	bcm_send_to_user(op, &msg_head, NULL, 0);
}

/*
 * bcm_rx_timeout_handler - when the (cyclic) CAN frame reception timed out
 */
static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
{
	struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);

	/* schedule before NET_RX_SOFTIRQ */
	tasklet_hi_schedule(&op->tsklet);

	/* no restart of the timer is done here! */

	/* if user wants to be informed, when cyclic CAN-Messages come back */
	if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) {
		/* clear received CAN frames to indicate 'nothing received' */
		memset(op->last_frames, 0, op->nframes * op->cfsiz);
	}

	return HRTIMER_NORESTART;
}

/*
 * bcm_rx_do_flush - helper for bcm_rx_thr_flush
 */
static inline int bcm_rx_do_flush(struct bcm_op *op, int update,
				  unsigned int index)
{
	struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;

	if ((op->last_frames) && (lcf->flags & RX_THR)) {
		if (update)
			bcm_rx_changed(op, lcf);
		return 1;
	}
	return 0;
}

/*
 * bcm_rx_thr_flush - Check for throttled data and send it to the userspace
 *
 * update == 0 : just check if throttled data is available  (any irq context)
 * update == 1 : check and send throttled data to userspace (soft_irq context)
 */
static int bcm_rx_thr_flush(struct bcm_op *op, int update)
{
	int updated = 0;

	if (op->nframes > 1) {
		unsigned int i;

		/* for MUX filter we start at index 1 */
		for (i = 1; i < op->nframes; i++)
			updated += bcm_rx_do_flush(op, update, i);

	} else {
		/* for RX_FILTER_ID and simple filter */
		updated += bcm_rx_do_flush(op, update, 0);
	}

	return updated;
}

static void bcm_rx_thr_tsklet(unsigned long data)
{
	struct bcm_op *op = (struct bcm_op *)data;

	/* push the changed data to the userspace */
	bcm_rx_thr_flush(op, 1);
}

/*
 * bcm_rx_thr_handler - the time for blocked content updates is over now:
 *                      Check for throttled data and send it to the userspace
 */
static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer)
{
	struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer);

	tasklet_schedule(&op->thrtsklet);

	if (bcm_rx_thr_flush(op, 0)) {
		hrtimer_forward(hrtimer, ktime_get(), op->kt_ival2);
		return HRTIMER_RESTART;
	} else {
		/* rearm throttle handling */
		op->kt_lastmsg = 0;
		return HRTIMER_NORESTART;
	}
}

/*
 * bcm_rx_handler - handle a CAN frame reception
 */
static void bcm_rx_handler(struct sk_buff *skb, void *data)
{
	struct bcm_op *op = (struct bcm_op *)data;
	const struct canfd_frame *rxframe = (struct canfd_frame *)skb->data;
	unsigned int i;

	if (op->can_id != rxframe->can_id)
		return;

	/* make sure to handle the correct frame type (CAN / CAN FD) */
	if (skb->len != op->cfsiz)
		return;

	/* disable timeout */
	hrtimer_cancel(&op->timer);

	/* save rx timestamp */
	op->rx_stamp = skb->tstamp;
	/* save originator for recvfrom() */
	op->rx_ifindex = skb->dev->ifindex;
	/* update statistics */
	op->frames_abs++;

	if (op->flags & RX_RTR_FRAME) {
		/* send reply for RTR-request (placed in op->frames[0]) */
		bcm_can_tx(op);
		return;
	}

	if (op->flags & RX_FILTER_ID) {
		/* the easiest case */
		bcm_rx_update_and_send(op, op->last_frames, rxframe);
		goto rx_starttimer;
	}

	if (op->nframes == 1) {
		/* simple compare with index 0 */
		bcm_rx_cmp_to_index(op, 0, rxframe);
		goto rx_starttimer;
	}

	if (op->nframes > 1) {
		/*
		 * multiplex compare
		 *
		 * find the first multiplex mask that fits.
		 * Remark: The MUX-mask is stored in index 0 - but only the
		 * first 64 bits of the frame data[] are relevant (CAN FD)
		 */

		for (i = 1; i < op->nframes; i++) {
			if ((get_u64(op->frames, 0) & get_u64(rxframe, 0)) ==
			    (get_u64(op->frames, 0) &
			     get_u64(op->frames + op->cfsiz * i, 0))) {
				bcm_rx_cmp_to_index(op, i, rxframe);
				break;
			}
		}
	}

rx_starttimer:
	bcm_rx_starttimer(op);
}

/*
 * helpers for bcm_op handling: find & delete bcm [rx|tx] op elements
 */
static struct bcm_op *bcm_find_op(struct list_head *ops,
				  struct bcm_msg_head *mh, int ifindex)
{
	struct bcm_op *op;

	list_for_each_entry(op, ops, list) {
		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME))
			return op;
	}

	return NULL;
}

static void bcm_remove_op(struct bcm_op *op)
{
	if (op->tsklet.func) {
		while (test_bit(TASKLET_STATE_SCHED, &op->tsklet.state) ||
		       test_bit(TASKLET_STATE_RUN, &op->tsklet.state) ||
		       hrtimer_active(&op->timer)) {
			hrtimer_cancel(&op->timer);
			tasklet_kill(&op->tsklet);
		}
	}

	if (op->thrtsklet.func) {
		while (test_bit(TASKLET_STATE_SCHED, &op->thrtsklet.state) ||
		       test_bit(TASKLET_STATE_RUN, &op->thrtsklet.state) ||
		       hrtimer_active(&op->thrtimer)) {
			hrtimer_cancel(&op->thrtimer);
			tasklet_kill(&op->thrtsklet);
		}
	}

	if ((op->frames) && (op->frames != &op->sframe))
		kfree(op->frames);

	if ((op->last_frames) && (op->last_frames != &op->last_sframe))
		kfree(op->last_frames);

	kfree(op);
}

static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
{
	if (op->rx_reg_dev == dev) {
		can_rx_unregister(dev_net(dev), dev, op->can_id,
				  REGMASK(op->can_id), bcm_rx_handler, op);

		/* mark as removed subscription */
		op->rx_reg_dev = NULL;
	} else
		printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device "
		       "mismatch %p %p\n", op->rx_reg_dev, dev);
}

/*
 * bcm_delete_rx_op - find and remove a rx op (returns number of removed ops)
 */
static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh,
			    int ifindex)
{
	struct bcm_op *op, *n;

	list_for_each_entry_safe(op, n, ops, list) {
		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {

			/*
			 * Don't care if we're bound or not (due to netdev
			 * problems) can_rx_unregister() is always a save
			 * thing to do here.
			 */
			if (op->ifindex) {
				/*
				 * Only remove subscriptions that had not
				 * been removed due to NETDEV_UNREGISTER
				 * in bcm_notifier()
				 */
				if (op->rx_reg_dev) {
					struct net_device *dev;

					dev = dev_get_by_index(sock_net(op->sk),
							       op->ifindex);
					if (dev) {
						bcm_rx_unreg(dev, op);
						dev_put(dev);
					}
				}
			} else
				can_rx_unregister(sock_net(op->sk), NULL,
						  op->can_id,
						  REGMASK(op->can_id),
						  bcm_rx_handler, op);

			list_del(&op->list);
			bcm_remove_op(op);
			return 1; /* done */
		}
	}

	return 0; /* not found */
}

/*
 * bcm_delete_tx_op - find and remove a tx op (returns number of removed ops)
 */
static int bcm_delete_tx_op(struct list_head *ops, struct bcm_msg_head *mh,
			    int ifindex)
{
	struct bcm_op *op, *n;

	list_for_each_entry_safe(op, n, ops, list) {
		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
			list_del(&op->list);
			bcm_remove_op(op);
			return 1; /* done */
		}
	}

	return 0; /* not found */
}

/*
 * bcm_read_op - read out a bcm_op and send it to the user (for bcm_sendmsg)
 */
static int bcm_read_op(struct list_head *ops, struct bcm_msg_head *msg_head,
		       int ifindex)
{
	struct bcm_op *op = bcm_find_op(ops, msg_head, ifindex);

	if (!op)
		return -EINVAL;

	/* put current values into msg_head */
	msg_head->flags   = op->flags;
	msg_head->count   = op->count;
	msg_head->ival1   = op->ival1;
	msg_head->ival2   = op->ival2;
	msg_head->nframes = op->nframes;

	bcm_send_to_user(op, msg_head, op->frames, 0);

	return MHSIZ;
}

/*
 * bcm_tx_setup - create or update a bcm tx op (for bcm_sendmsg)
 */
static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
			int ifindex, struct sock *sk)
{
	struct bcm_sock *bo = bcm_sk(sk);
	struct bcm_op *op;
	struct canfd_frame *cf;
	unsigned int i;
	int err;

	/* we need a real device to send frames */
	if (!ifindex)
		return -ENODEV;

	/* check nframes boundaries - we need at least one CAN frame */
	if (msg_head->nframes < 1 || msg_head->nframes > MAX_NFRAMES)
		return -EINVAL;

	/* check the given can_id */
	op = bcm_find_op(&bo->tx_ops, msg_head, ifindex);
	if (op) {
		/* update existing BCM operation */

		/*
		 * Do we need more space for the CAN frames than currently
		 * allocated? -> This is a _really_ unusual use-case and
		 * therefore (complexity / locking) it is not supported.
		 */
		if (msg_head->nframes > op->nframes)
			return -E2BIG;

		/* update CAN frames content */
		for (i = 0; i < msg_head->nframes; i++) {

			cf = op->frames + op->cfsiz * i;
			err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);

			if (op->flags & CAN_FD_FRAME) {
				if (cf->len > 64)
					err = -EINVAL;
			} else {
				if (cf->len > 8)
					err = -EINVAL;
			}

			if (err < 0)
				return err;

			if (msg_head->flags & TX_CP_CAN_ID) {
				/* copy can_id into frame */
				cf->can_id = msg_head->can_id;
			}
		}
		op->flags = msg_head->flags;

	} else {
		/* insert new BCM operation for the given can_id */

		op = kzalloc(OPSIZ, GFP_KERNEL);
		if (!op)
			return -ENOMEM;

		op->can_id = msg_head->can_id;
		op->cfsiz = CFSIZ(msg_head->flags);
		op->flags = msg_head->flags;

		/* create array for CAN frames and copy the data */
		if (msg_head->nframes > 1) {
			op->frames = kmalloc_array(msg_head->nframes,
						   op->cfsiz,
						   GFP_KERNEL);
			if (!op->frames) {
				kfree(op);
				return -ENOMEM;
			}
		} else
			op->frames = &op->sframe;

		for (i = 0; i < msg_head->nframes; i++) {

			cf = op->frames + op->cfsiz * i;
			err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz);

			if (op->flags & CAN_FD_FRAME) {
				if (cf->len > 64)
					err = -EINVAL;
			} else {
				if (cf->len > 8)
					err = -EINVAL;
			}

			if (err < 0) {
				if (op->frames != &op->sframe)
					kfree(op->frames);
				kfree(op);
				return err;
			}

			if (msg_head->flags & TX_CP_CAN_ID) {
				/* copy can_id into frame */
				cf->can_id = msg_head->can_id;
			}
		}

		/* tx_ops never compare with previous received messages */
		op->last_frames = NULL;

		/* bcm_can_tx / bcm_tx_timeout_handler needs this */
		op->sk = sk;
		op->ifindex = ifindex;

		/* initialize uninitialized (kzalloc) structure */
		hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
		op->timer.function = bcm_tx_timeout_handler;

		/* initialize tasklet for tx countevent notification */
		tasklet_init(&op->tsklet, bcm_tx_timeout_tsklet,
			     (unsigned long) op);

		/* currently unused in tx_ops */
		hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

		/* add this bcm_op to the list of the tx_ops */
		list_add(&op->list, &bo->tx_ops);

	} /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */

	if (op->nframes != msg_head->nframes) {
		op->nframes   = msg_head->nframes;
		/* start multiple frame transmission with index 0 */
		op->currframe = 0;
	}

	/* check flags */

	if (op->flags & TX_RESET_MULTI_IDX) {
		/* start multiple frame transmission with index 0 */
		op->currframe = 0;
	}

	if (op->flags & SETTIMER) {
		/* set timer values */
		op->count = msg_head->count;
		op->ival1 = msg_head->ival1;
		op->ival2 = msg_head->ival2;
		op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
		op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);

		/* disable an active timer due to zero values? */
		if (!op->kt_ival1 && !op->kt_ival2)
			hrtimer_cancel(&op->timer);
	}

	if (op->flags & STARTTIMER) {
		hrtimer_cancel(&op->timer);
		/* spec: send CAN frame when starting timer */
		op->flags |= TX_ANNOUNCE;
	}

	if (op->flags & TX_ANNOUNCE) {
		bcm_can_tx(op);
		if (op->count)
			op->count--;
	}

	if (op->flags & STARTTIMER)
		bcm_tx_start_timer(op);

	return msg_head->nframes * op->cfsiz + MHSIZ;
}

/*
 * bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg)
 */
static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
			int ifindex, struct sock *sk)
{
	struct bcm_sock *bo = bcm_sk(sk);
	struct bcm_op *op;
	int do_rx_register;
	int err = 0;

	if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) {
		/* be robust against wrong usage ... */
		msg_head->flags |= RX_FILTER_ID;
		/* ignore trailing garbage */
		msg_head->nframes = 0;
	}

	/* the first element contains the mux-mask => MAX_NFRAMES + 1  */
	if (msg_head->nframes > MAX_NFRAMES + 1)
		return -EINVAL;

	if ((msg_head->flags & RX_RTR_FRAME) &&
	    ((msg_head->nframes != 1) ||
	     (!(msg_head->can_id & CAN_RTR_FLAG))))
		return -EINVAL;

	/* check the given can_id */
	op = bcm_find_op(&bo->rx_ops, msg_head, ifindex);
	if (op) {
		/* update existing BCM operation */

		/*
		 * Do we need more space for the CAN frames than currently
		 * allocated? -> This is a _really_ unusual use-case and
		 * therefore (complexity / locking) it is not supported.
		 */
		if (msg_head->nframes > op->nframes)
			return -E2BIG;

		if (msg_head->nframes) {
			/* update CAN frames content */
			err = memcpy_from_msg(op->frames, msg,
					      msg_head->nframes * op->cfsiz);
			if (err < 0)
				return err;

			/* clear last_frames to indicate 'nothing received' */
			memset(op->last_frames, 0, msg_head->nframes * op->cfsiz);
		}

		op->nframes = msg_head->nframes;
		op->flags = msg_head->flags;

		/* Only an update -> do not call can_rx_register() */
		do_rx_register = 0;

	} else {
		/* insert new BCM operation for the given can_id */
		op = kzalloc(OPSIZ, GFP_KERNEL);
		if (!op)
			return -ENOMEM;

		op->can_id = msg_head->can_id;
		op->nframes = msg_head->nframes;
		op->cfsiz = CFSIZ(msg_head->flags);
		op->flags = msg_head->flags;

		if (msg_head->nframes > 1) {
			/* create array for CAN frames and copy the data */
			op->frames = kmalloc_array(msg_head->nframes,
						   op->cfsiz,
						   GFP_KERNEL);
			if (!op->frames) {
				kfree(op);
				return -ENOMEM;
			}

			/* create and init array for received CAN frames */
			op->last_frames = kcalloc(msg_head->nframes,
						  op->cfsiz,
						  GFP_KERNEL);
			if (!op->last_frames) {
				kfree(op->frames);
				kfree(op);
				return -ENOMEM;
			}

		} else {
			op->frames = &op->sframe;
			op->last_frames = &op->last_sframe;
		}

		if (msg_head->nframes) {
			err = memcpy_from_msg(op->frames, msg,
					      msg_head->nframes * op->cfsiz);
			if (err < 0) {
				if (op->frames != &op->sframe)
					kfree(op->frames);
				if (op->last_frames != &op->last_sframe)
					kfree(op->last_frames);
				kfree(op);
				return err;
			}
		}

		/* bcm_can_tx / bcm_tx_timeout_handler needs this */
		op->sk = sk;
		op->ifindex = ifindex;

		/* ifindex for timeout events w/o previous frame reception */
		op->rx_ifindex = ifindex;

		/* initialize uninitialized (kzalloc) structure */
		hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
		op->timer.function = bcm_rx_timeout_handler;

		/* initialize tasklet for rx timeout notification */
		tasklet_init(&op->tsklet, bcm_rx_timeout_tsklet,
			     (unsigned long) op);

		hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
		op->thrtimer.function = bcm_rx_thr_handler;

		/* initialize tasklet for rx throttle handling */
		tasklet_init(&op->thrtsklet, bcm_rx_thr_tsklet,
			     (unsigned long) op);

		/* add this bcm_op to the list of the rx_ops */
		list_add(&op->list, &bo->rx_ops);

		/* call can_rx_register() */
		do_rx_register = 1;

	} /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */

	/* check flags */

	if (op->flags & RX_RTR_FRAME) {
		struct canfd_frame *frame0 = op->frames;

		/* no timers in RTR-mode */
		hrtimer_cancel(&op->thrtimer);
		hrtimer_cancel(&op->timer);

		/*
		 * funny feature in RX(!)_SETUP only for RTR-mode:
		 * copy can_id into frame BUT without RTR-flag to
		 * prevent a full-load-loopback-test ... ;-]
		 */
		if ((op->flags & TX_CP_CAN_ID) ||
		    (frame0->can_id == op->can_id))
			frame0->can_id = op->can_id & ~CAN_RTR_FLAG;

	} else {
		if (op->flags & SETTIMER) {

			/* set timer value */
			op->ival1 = msg_head->ival1;
			op->ival2 = msg_head->ival2;
			op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1);
			op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2);

			/* disable an active timer due to zero value? */
			if (!op->kt_ival1)
				hrtimer_cancel(&op->timer);

			/*
			 * In any case cancel the throttle timer, flush
			 * potentially blocked msgs and reset throttle handling
			 */
			op->kt_lastmsg = 0;
			hrtimer_cancel(&op->thrtimer);
			bcm_rx_thr_flush(op, 1);
		}

		if ((op->flags & STARTTIMER) && op->kt_ival1)
			hrtimer_start(&op->timer, op->kt_ival1,
				      HRTIMER_MODE_REL);
	}

	/* now we can register for can_ids, if we added a new bcm_op */
	if (do_rx_register) {
		if (ifindex) {
			struct net_device *dev;

			dev = dev_get_by_index(sock_net(sk), ifindex);
			if (dev) {
				err = can_rx_register(sock_net(sk), dev,
						      op->can_id,
						      REGMASK(op->can_id),
						      bcm_rx_handler, op,
						      "bcm", sk);

				op->rx_reg_dev = dev;
				dev_put(dev);
			}

		} else
			err = can_rx_register(sock_net(sk), NULL, op->can_id,
					      REGMASK(op->can_id),
					      bcm_rx_handler, op, "bcm", sk);
		if (err) {
			/* this bcm rx op is broken -> remove it */
			list_del(&op->list);
			bcm_remove_op(op);
			return err;
		}
	}

	return msg_head->nframes * op->cfsiz + MHSIZ;
}

/*
 * bcm_tx_send - send a single CAN frame to the CAN interface (for bcm_sendmsg)
 */
static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk,
		       int cfsiz)
{
	struct sk_buff *skb;
	struct net_device *dev;
	int err;

	/* we need a real device to send frames */
	if (!ifindex)
		return -ENODEV;

	skb = alloc_skb(cfsiz + sizeof(struct can_skb_priv), GFP_KERNEL);
	if (!skb)
		return -ENOMEM;

	can_skb_reserve(skb);

	err = memcpy_from_msg(skb_put(skb, cfsiz), msg, cfsiz);
	if (err < 0) {
		kfree_skb(skb);
		return err;
	}

	dev = dev_get_by_index(sock_net(sk), ifindex);
	if (!dev) {
		kfree_skb(skb);
		return -ENODEV;
	}

	can_skb_prv(skb)->ifindex = dev->ifindex;
	can_skb_prv(skb)->skbcnt = 0;
	skb->dev = dev;
	can_skb_set_owner(skb, sk);
	err = can_send(skb, 1); /* send with loopback */
	dev_put(dev);

	if (err)
		return err;

	return cfsiz + MHSIZ;
}

/*
 * bcm_sendmsg - process BCM commands (opcodes) from the userspace
 */
static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
{
	struct sock *sk = sock->sk;
	struct bcm_sock *bo = bcm_sk(sk);
	int ifindex = bo->ifindex; /* default ifindex for this bcm_op */
	struct bcm_msg_head msg_head;
	int cfsiz;
	int ret; /* read bytes or error codes as return value */

	if (!bo->bound)
		return -ENOTCONN;

	/* check for valid message length from userspace */
	if (size < MHSIZ)
		return -EINVAL;

	/* read message head information */
	ret = memcpy_from_msg((u8 *)&msg_head, msg, MHSIZ);
	if (ret < 0)
		return ret;

	cfsiz = CFSIZ(msg_head.flags);
	if ((size - MHSIZ) % cfsiz)
		return -EINVAL;

	/* check for alternative ifindex for this bcm_op */

	if (!ifindex && msg->msg_name) {
		/* no bound device as default => check msg_name */
		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);

		if (msg->msg_namelen < sizeof(*addr))
			return -EINVAL;

		if (addr->can_family != AF_CAN)
			return -EINVAL;

		/* ifindex from sendto() */
		ifindex = addr->can_ifindex;

		if (ifindex) {
			struct net_device *dev;

			dev = dev_get_by_index(sock_net(sk), ifindex);
			if (!dev)
				return -ENODEV;

			if (dev->type != ARPHRD_CAN) {
				dev_put(dev);
				return -ENODEV;
			}

			dev_put(dev);
		}
	}

	lock_sock(sk);

	switch (msg_head.opcode) {

	case TX_SETUP:
		ret = bcm_tx_setup(&msg_head, msg, ifindex, sk);
		break;

	case RX_SETUP:
		ret = bcm_rx_setup(&msg_head, msg, ifindex, sk);
		break;

	case TX_DELETE:
		if (bcm_delete_tx_op(&bo->tx_ops, &msg_head, ifindex))
			ret = MHSIZ;
		else
			ret = -EINVAL;
		break;

	case RX_DELETE:
		if (bcm_delete_rx_op(&bo->rx_ops, &msg_head, ifindex))
			ret = MHSIZ;
		else
			ret = -EINVAL;
		break;

	case TX_READ:
		/* reuse msg_head for the reply to TX_READ */
		msg_head.opcode  = TX_STATUS;
		ret = bcm_read_op(&bo->tx_ops, &msg_head, ifindex);
		break;

	case RX_READ:
		/* reuse msg_head for the reply to RX_READ */
		msg_head.opcode  = RX_STATUS;
		ret = bcm_read_op(&bo->rx_ops, &msg_head, ifindex);
		break;

	case TX_SEND:
		/* we need exactly one CAN frame behind the msg head */
		if ((msg_head.nframes != 1) || (size != cfsiz + MHSIZ))
			ret = -EINVAL;
		else
			ret = bcm_tx_send(msg, ifindex, sk, cfsiz);
		break;

	default:
		ret = -EINVAL;
		break;
	}

	release_sock(sk);

	return ret;
}

/*
 * notification handler for netdevice status changes
 */
static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
			void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	struct bcm_sock *bo = container_of(nb, struct bcm_sock, notifier);
	struct sock *sk = &bo->sk;
	struct bcm_op *op;
	int notify_enodev = 0;

	if (!net_eq(dev_net(dev), sock_net(sk)))
		return NOTIFY_DONE;

	if (dev->type != ARPHRD_CAN)
		return NOTIFY_DONE;

	switch (msg) {

	case NETDEV_UNREGISTER:
		lock_sock(sk);

		/* remove device specific receive entries */
		list_for_each_entry(op, &bo->rx_ops, list)
			if (op->rx_reg_dev == dev)
				bcm_rx_unreg(dev, op);

		/* remove device reference, if this is our bound device */
		if (bo->bound && bo->ifindex == dev->ifindex) {
			bo->bound   = 0;
			bo->ifindex = 0;
			notify_enodev = 1;
		}

		release_sock(sk);

		if (notify_enodev) {
			sk->sk_err = ENODEV;
			if (!sock_flag(sk, SOCK_DEAD))
				sk->sk_error_report(sk);
		}
		break;

	case NETDEV_DOWN:
		if (bo->bound && bo->ifindex == dev->ifindex) {
			sk->sk_err = ENETDOWN;
			if (!sock_flag(sk, SOCK_DEAD))
				sk->sk_error_report(sk);
		}
	}

	return NOTIFY_DONE;
}

/*
 * initial settings for all BCM sockets to be set at socket creation time
 */
static int bcm_init(struct sock *sk)
{
	struct bcm_sock *bo = bcm_sk(sk);

	bo->bound            = 0;
	bo->ifindex          = 0;
	bo->dropped_usr_msgs = 0;
	bo->bcm_proc_read    = NULL;

	INIT_LIST_HEAD(&bo->tx_ops);
	INIT_LIST_HEAD(&bo->rx_ops);

	/* set notifier */
	bo->notifier.notifier_call = bcm_notifier;

	register_netdevice_notifier(&bo->notifier);

	return 0;
}

/*
 * standard socket functions
 */
static int bcm_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	struct net *net;
	struct bcm_sock *bo;
	struct bcm_op *op, *next;

	if (!sk)
		return 0;

	net = sock_net(sk);
	bo = bcm_sk(sk);

	/* remove bcm_ops, timer, rx_unregister(), etc. */

	unregister_netdevice_notifier(&bo->notifier);

	lock_sock(sk);

	list_for_each_entry_safe(op, next, &bo->tx_ops, list)
		bcm_remove_op(op);

	list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
		/*
		 * Don't care if we're bound or not (due to netdev problems)
		 * can_rx_unregister() is always a save thing to do here.
		 */
		if (op->ifindex) {
			/*
			 * Only remove subscriptions that had not
			 * been removed due to NETDEV_UNREGISTER
			 * in bcm_notifier()
			 */
			if (op->rx_reg_dev) {
				struct net_device *dev;

				dev = dev_get_by_index(net, op->ifindex);
				if (dev) {
					bcm_rx_unreg(dev, op);
					dev_put(dev);
				}
			}
		} else
			can_rx_unregister(net, NULL, op->can_id,
					  REGMASK(op->can_id),
					  bcm_rx_handler, op);

		bcm_remove_op(op);
	}

#if IS_ENABLED(CONFIG_PROC_FS)
	/* remove procfs entry */
	if (net->can.bcmproc_dir && bo->bcm_proc_read)
		remove_proc_entry(bo->procname, net->can.bcmproc_dir);
#endif /* CONFIG_PROC_FS */

	/* remove device reference */
	if (bo->bound) {
		bo->bound   = 0;
		bo->ifindex = 0;
	}

	sock_orphan(sk);
	sock->sk = NULL;

	release_sock(sk);
	sock_put(sk);

	return 0;
}

static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
		       int flags)
{
	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
	struct sock *sk = sock->sk;
	struct bcm_sock *bo = bcm_sk(sk);
	struct net *net = sock_net(sk);
	int ret = 0;

	if (len < sizeof(*addr))
		return -EINVAL;

	lock_sock(sk);

	if (bo->bound) {
		ret = -EISCONN;
		goto fail;
	}

	/* bind a device to this socket */
	if (addr->can_ifindex) {
		struct net_device *dev;

		dev = dev_get_by_index(net, addr->can_ifindex);
		if (!dev) {
			ret = -ENODEV;
			goto fail;
		}
		if (dev->type != ARPHRD_CAN) {
			dev_put(dev);
			ret = -ENODEV;
			goto fail;
		}

		bo->ifindex = dev->ifindex;
		dev_put(dev);

	} else {
		/* no interface reference for ifindex = 0 ('any' CAN device) */
		bo->ifindex = 0;
	}

#if IS_ENABLED(CONFIG_PROC_FS)
	if (net->can.bcmproc_dir) {
		/* unique socket address as filename */
		sprintf(bo->procname, "%lu", sock_i_ino(sk));
		bo->bcm_proc_read = proc_create_net_single(bo->procname, 0644,
						     net->can.bcmproc_dir,
						     bcm_proc_show, sk);
		if (!bo->bcm_proc_read) {
			ret = -ENOMEM;
			goto fail;
		}
	}
#endif /* CONFIG_PROC_FS */

	bo->bound = 1;

fail:
	release_sock(sk);

	return ret;
}

static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
		       int flags)
{
	struct sock *sk = sock->sk;
	struct sk_buff *skb;
	int error = 0;
	int noblock;
	int err;

	noblock =  flags & MSG_DONTWAIT;
	flags   &= ~MSG_DONTWAIT;
	skb = skb_recv_datagram(sk, flags, noblock, &error);
	if (!skb)
		return error;

	if (skb->len < size)
		size = skb->len;

	err = memcpy_to_msg(msg, skb->data, size);
	if (err < 0) {
		skb_free_datagram(sk, skb);
		return err;
	}

	sock_recv_ts_and_drops(msg, sk, skb);

	if (msg->msg_name) {
		__sockaddr_check_size(sizeof(struct sockaddr_can));
		msg->msg_namelen = sizeof(struct sockaddr_can);
		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
	}

	skb_free_datagram(sk, skb);

	return size;
}

static const struct proto_ops bcm_ops = {
	.family        = PF_CAN,
	.release       = bcm_release,
	.bind          = sock_no_bind,
	.connect       = bcm_connect,
	.socketpair    = sock_no_socketpair,
	.accept        = sock_no_accept,
	.getname       = sock_no_getname,
	.poll_mask     = datagram_poll_mask,
	.ioctl         = can_ioctl,	/* use can_ioctl() from af_can.c */
	.listen        = sock_no_listen,
	.shutdown      = sock_no_shutdown,
	.setsockopt    = sock_no_setsockopt,
	.getsockopt    = sock_no_getsockopt,
	.sendmsg       = bcm_sendmsg,
	.recvmsg       = bcm_recvmsg,
	.mmap          = sock_no_mmap,
	.sendpage      = sock_no_sendpage,
};

static struct proto bcm_proto __read_mostly = {
	.name       = "CAN_BCM",
	.owner      = THIS_MODULE,
	.obj_size   = sizeof(struct bcm_sock),
	.init       = bcm_init,
};

static const struct can_proto bcm_can_proto = {
	.type       = SOCK_DGRAM,
	.protocol   = CAN_BCM,
	.ops        = &bcm_ops,
	.prot       = &bcm_proto,
};

static int canbcm_pernet_init(struct net *net)
{
#if IS_ENABLED(CONFIG_PROC_FS)
	/* create /proc/net/can-bcm directory */
	net->can.bcmproc_dir = proc_net_mkdir(net, "can-bcm", net->proc_net);
#endif /* CONFIG_PROC_FS */

	return 0;
}

static void canbcm_pernet_exit(struct net *net)
{
#if IS_ENABLED(CONFIG_PROC_FS)
	/* remove /proc/net/can-bcm directory */
	if (net->can.bcmproc_dir)
		remove_proc_entry("can-bcm", net->proc_net);
#endif /* CONFIG_PROC_FS */
}

static struct pernet_operations canbcm_pernet_ops __read_mostly = {
	.init = canbcm_pernet_init,
	.exit = canbcm_pernet_exit,
};

static int __init bcm_module_init(void)
{
	int err;

	pr_info("can: broadcast manager protocol (rev " CAN_BCM_VERSION " t)\n");

	err = can_proto_register(&bcm_can_proto);
	if (err < 0) {
		printk(KERN_ERR "can: registration of bcm protocol failed\n");
		return err;
	}

	register_pernet_subsys(&canbcm_pernet_ops);
	return 0;
}

static void __exit bcm_module_exit(void)
{
	can_proto_unregister(&bcm_can_proto);
	unregister_pernet_subsys(&canbcm_pernet_ops);
}

module_init(bcm_module_init);
module_exit(bcm_module_exit);