aboutsummaryrefslogtreecommitdiffstats
path: root/epan/dissectors/packet-socketcan.c
blob: e441c44ade8d348d9c6d05debdf953e1cab2f5a2 (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
/* packet-socketcan.c
 * Routines for disassembly of packets from SocketCAN
 * Felix Obenhuber <felix@obenhuber.de>
 *
 * Added support for the DeviceNet Dissector
 * Hans-Joergen Gunnarsson <hag@hms.se>
 * Copyright 2013
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/expert.h>
#include <epan/decode_as.h>
#include <epan/uat.h>
#include <wiretap/wtap.h>

#include "packet-sll.h"
#include "packet-socketcan.h"

void proto_register_socketcan(void);
void proto_reg_handoff_socketcan(void);

static int hf_can_len;
static int hf_can_infoent_ext;
static int hf_can_infoent_std;
static int hf_can_extflag;
static int hf_can_rtrflag;
static int hf_can_errflag;
static int hf_can_reserved;
static int hf_can_padding;

static int hf_can_err_tx_timeout;
static int hf_can_err_lostarb;
static int hf_can_err_ctrl;
static int hf_can_err_prot;
static int hf_can_err_trx;
static int hf_can_err_ack;
static int hf_can_err_busoff;
static int hf_can_err_buserror;
static int hf_can_err_restarted;
static int hf_can_err_reserved;

static int hf_can_err_lostarb_bit_number;

static int hf_can_err_ctrl_rx_overflow;
static int hf_can_err_ctrl_tx_overflow;
static int hf_can_err_ctrl_rx_warning;
static int hf_can_err_ctrl_tx_warning;
static int hf_can_err_ctrl_rx_passive;
static int hf_can_err_ctrl_tx_passive;
static int hf_can_err_ctrl_active;

static int hf_can_err_prot_error_type_bit;
static int hf_can_err_prot_error_type_form;
static int hf_can_err_prot_error_type_stuff;
static int hf_can_err_prot_error_type_bit0;
static int hf_can_err_prot_error_type_bit1;
static int hf_can_err_prot_error_type_overload;
static int hf_can_err_prot_error_type_active;
static int hf_can_err_prot_error_type_tx;

static int hf_can_err_prot_error_location;

static int hf_can_err_trx_canh;
static int hf_can_err_trx_canl;

static int hf_can_err_ctrl_specific;

static int hf_canxl_priority;
static int hf_canxl_vcid;
static int hf_canxl_secflag;
static int hf_canxl_sdu_type;
static int hf_canxl_len;
static int hf_canxl_acceptance_field;

static expert_field ei_can_err_dlc_mismatch;

static int hf_canfd_brsflag;
static int hf_canfd_esiflag;

static gint ett_can;
static gint ett_can_fd;
static gint ett_can_xl;

static int proto_can;
static int proto_canfd;
static int proto_canxl;

static gboolean byte_swap = FALSE;
static gboolean heuristic_first = FALSE;

static heur_dissector_list_t heur_subdissector_list;
static heur_dtbl_entry_t *heur_dtbl_entry;

#define LINUX_CAN_STD   0
#define LINUX_CAN_EXT   1
#define LINUX_CAN_ERR   2

#define CAN_LEN_OFFSET     4
#define CAN_DATA_OFFSET    8

#define CANFD_FLAG_OFFSET  5

#define CANFD_BRS 0x01 /* bit rate switch (second bitrate for payload data) */
#define CANFD_ESI 0x02 /* error state indicator of the transmitting node */

#define CANXL_LEN_OFFSET   6
#define CANXL_DATA_OFFSET  12

static dissector_table_t can_id_dissector_table = NULL;
static dissector_table_t can_extended_id_dissector_table = NULL;
static dissector_table_t subdissector_table = NULL;
static dissector_table_t canxl_sdu_type_dissector_table = NULL;
static dissector_handle_t socketcan_classic_handle;
static dissector_handle_t socketcan_fd_handle;
static dissector_handle_t socketcan_xl_handle;
static dissector_handle_t socketcan_bigendian_handle;


static const value_string can_err_prot_error_location_vals[] = {
    { 0x00, "unspecified" },
    { 0x02, "ID bits 28 - 21 (SFF: 10 - 3)" },
    { 0x03, "start of frame" },
    { 0x04, "substitute RTR (SFF: RTR)" },
    { 0x05, "identifier extension" },
    { 0x06, "ID bits 20 - 18 (SFF: 2 - 0)" },
    { 0x07, "ID bits 17-13" },
    { 0x08, "CRC sequence" },
    { 0x09, "reserved bit 0" },
    { 0x0A, "data section" },
    { 0x0B, "data length code" },
    { 0x0C, "RTR" },
    { 0x0D, "reserved bit 1" },
    { 0x0E, "ID bits 4-0" },
    { 0x0F, "ID bits 12-5" },
    { 0x12, "intermission" },
    { 0x18, "CRC delimiter" },
    { 0x19, "ACK slot" },
    { 0x1A, "end of frame" },
    { 0x1B, "ACK delimiter" },
    { 0, NULL }
};

static const value_string can_err_trx_canh_vals[] = {
    { 0x00, "unspecified" },
    { 0x04, "no wire" },
    { 0x05, "short to BAT" },
    { 0x06, "short to VCC" },
    { 0x07, "short to GND" },
    { 0, NULL }
};

static const value_string can_err_trx_canl_vals[] = {
    { 0x00, "unspecified" },
    { 0x04, "no wire" },
    { 0x05, "short to BAT" },
    { 0x06, "short to VCC" },
    { 0x07, "short to GND" },
    { 0x08, "short to CANH" },
    { 0, NULL }
};

static const value_string canxl_sdu_type_vals[] = {
    { 0x00, "Reserved" },
    { CANXL_SDU_TYPE_CONTENT_BASED_ADDRESSING, "Content-based Addressing" },
    { 0x02, "Reserved for future use" },
    { CANXL_SDU_TYPE_CLASSICAL_CAN_AND_CAN_FD_MAPPED_TUNNELING, "Classical CAN/CAN FD mapped tunneling" },
    { CANXL_SDU_TYPE_IEEE_802_3_MAC_FRAME_TUNNELLING, "IEEE 802.3 (MAC frame) tunneling" },
    { CANXL_SDU_TYPE_IEEE_802_3_MAC_FRAME_MAPPED_TUNNELING, "IEEE 802.3 (MAC frame) mapped tunneling" },
    { CANXL_SDU_TYPE_CLASSICAL_CAN_MAPPED_TUNNELING, "Classical CAN mapped tunneling" },
    { CANXL_SDU_TYPE_CAN_FD_MAPPED_TUNNELING, "CAN FD mapped tunneling" },
    { 0xFF, "Reserved" },
    { 0, NULL }
};

/********* UATs *********/

/* Interface Config UAT */
typedef struct _interface_config {
    guint   interface_id;
    gchar  *interface_name;
    guint   bus_id;
} interface_config_t;

#define DATAFILE_CAN_INTERFACE_MAPPING "CAN_interface_mapping"

static GHashTable *data_can_interfaces_by_id = NULL;
static GHashTable *data_can_interfaces_by_name = NULL;
static interface_config_t *interface_configs = NULL;
static guint interface_config_num = 0;

UAT_HEX_CB_DEF(interface_configs, interface_id, interface_config_t)
UAT_CSTRING_CB_DEF(interface_configs, interface_name, interface_config_t)
UAT_HEX_CB_DEF(interface_configs, bus_id, interface_config_t)

static void *
copy_interface_config_cb(void *n, const void *o, size_t size _U_) {
    interface_config_t *new_rec = (interface_config_t *)n;
    const interface_config_t *old_rec = (const interface_config_t *)o;

    new_rec->interface_id = old_rec->interface_id;
    new_rec->interface_name = g_strdup(old_rec->interface_name);
    new_rec->bus_id = old_rec->bus_id;
    return new_rec;
}

static bool
update_interface_config(void *r, char **err) {
    interface_config_t *rec = (interface_config_t *)r;

    if (rec->interface_id > 0xffffffff) {
        *err = ws_strdup_printf("We currently only support 32 bit identifiers (ID: %i  Name: %s)",
                                rec->interface_id, rec->interface_name);
        return FALSE;
    }

    if (rec->bus_id > 0xffff) {
        *err = ws_strdup_printf("We currently only support 16 bit bus identifiers (ID: %i  Name: %s  Bus-ID: %i)",
                                rec->interface_id, rec->interface_name, rec->bus_id);
        return FALSE;
    }

    return TRUE;
}

static void
free_interface_config_cb(void *r) {
    interface_config_t *rec = (interface_config_t *)r;

    /* freeing result of g_strdup */
    g_free(rec->interface_name);
    rec->interface_name = NULL;
}

static interface_config_t *
ht_lookup_interface_config_by_id(unsigned int identifier) {
    interface_config_t *tmp = NULL;
    unsigned int       *id = NULL;

    if (interface_configs == NULL) {
        return NULL;
    }

    id = wmem_new(wmem_epan_scope(), unsigned int);
    *id = (unsigned int)identifier;
    tmp = (interface_config_t *)g_hash_table_lookup(data_can_interfaces_by_id, id);
    wmem_free(wmem_epan_scope(), id);

    return tmp;
}

static interface_config_t *
ht_lookup_interface_config_by_name(const gchar *name) {
    interface_config_t *tmp = NULL;
    gchar              *key = NULL;

    if (interface_configs == NULL) {
        return NULL;
    }

    key = wmem_strdup(wmem_epan_scope(), name);
    tmp = (interface_config_t *)g_hash_table_lookup(data_can_interfaces_by_name, key);
    wmem_free(wmem_epan_scope(), key);

    return tmp;
}

static void
can_free_key(gpointer key) {
    wmem_free(wmem_epan_scope(), key);
}

static void
post_update_can_interfaces_cb(void) {
    guint  i;
    int   *key_id = NULL;
    gchar *key_name = NULL;

    /* destroy old hash tables, if they exist */
    if (data_can_interfaces_by_id) {
        g_hash_table_destroy(data_can_interfaces_by_id);
        data_can_interfaces_by_id = NULL;
    }
    if (data_can_interfaces_by_name) {
        g_hash_table_destroy(data_can_interfaces_by_name);
        data_can_interfaces_by_name = NULL;
    }

    /* create new hash table */
    data_can_interfaces_by_id = g_hash_table_new_full(g_int_hash, g_int_equal, &can_free_key, NULL);
    data_can_interfaces_by_name = g_hash_table_new_full(g_str_hash, g_str_equal, &can_free_key, NULL);

    if (data_can_interfaces_by_id == NULL || data_can_interfaces_by_name == NULL || interface_configs == NULL || interface_config_num == 0) {
        return;
    }

    for (i = 0; i < interface_config_num; i++) {
        if (interface_configs[i].interface_id != 0xfffffff) {
            key_id = wmem_new(wmem_epan_scope(), int);
            *key_id = interface_configs[i].interface_id;
            g_hash_table_insert(data_can_interfaces_by_id, key_id, &interface_configs[i]);
        }

        if (interface_configs[i].interface_name != NULL && interface_configs[i].interface_name[0] != 0) {
            key_name = wmem_strdup(wmem_epan_scope(), interface_configs[i].interface_name);
            g_hash_table_insert(data_can_interfaces_by_name, key_name, &interface_configs[i]);
        }
    }
}

/* We match based on the config in the following order:
 * - interface_name matches and interface_id matches
 * - interface_name matches and interface_id = 0xffffffff
 * - interface_name = ""    and interface_id matches
 */
static guint
get_bus_id(packet_info *pinfo) {
    if (!(pinfo->rec->presence_flags & WTAP_HAS_INTERFACE_ID)) {
        return 0;
    }

    guint32             interface_id = pinfo->rec->rec_header.packet_header.interface_id;
    unsigned            section_number = pinfo->rec->presence_flags & WTAP_HAS_SECTION_NUMBER ? pinfo->rec->section_number : 0;
    const char         *interface_name = epan_get_interface_name(pinfo->epan, interface_id, section_number);
    interface_config_t *tmp = NULL;

    if (interface_name != NULL && interface_name[0] != 0) {
        tmp = ht_lookup_interface_config_by_name(interface_name);

        if (tmp != NULL && (tmp->interface_id == 0xffffffff || tmp->interface_id == interface_id)) {
            /* name + id match or name match and id = any */
            return tmp->bus_id;
        }

        tmp = ht_lookup_interface_config_by_id(interface_id);

        if (tmp != NULL && (tmp->interface_name == NULL || tmp->interface_name[0] == 0)) {
            /* id matches and name is any */
            return tmp->bus_id;
        }
    }

    /* we found nothing */
    return 0;
}

/* Senders and Receivers UAT */
typedef struct _sender_receiver_config {
    guint   bus_id;
    guint   can_id;
    gchar  *sender_name;
    gchar  *receiver_name;
} sender_receiver_config_t;

#define DATAFILE_CAN_SENDER_RECEIVER "CAN_senders_receivers"

static GHashTable *data_sender_receiver = NULL;
static sender_receiver_config_t *sender_receiver_configs = NULL;
static guint sender_receiver_config_num = 0;

UAT_HEX_CB_DEF(sender_receiver_configs, bus_id, sender_receiver_config_t)
UAT_HEX_CB_DEF(sender_receiver_configs, can_id, sender_receiver_config_t)
UAT_CSTRING_CB_DEF(sender_receiver_configs, sender_name, sender_receiver_config_t)
UAT_CSTRING_CB_DEF(sender_receiver_configs, receiver_name, sender_receiver_config_t)

static void *
copy_sender_receiver_config_cb(void *n, const void *o, size_t size _U_) {
    sender_receiver_config_t *new_rec = (sender_receiver_config_t *)n;
    const sender_receiver_config_t *old_rec = (const sender_receiver_config_t *)o;

    new_rec->bus_id = old_rec->bus_id;
    new_rec->can_id = old_rec->can_id;
    new_rec->sender_name = g_strdup(old_rec->sender_name);
    new_rec->receiver_name = g_strdup(old_rec->receiver_name);
    return new_rec;
}

static bool
update_sender_receiver_config(void *r, char **err) {
    sender_receiver_config_t *rec = (sender_receiver_config_t *)r;

    if (rec->bus_id > 0xffff) {
        *err = ws_strdup_printf("We currently only support 16 bit bus identifiers (Bus ID: %i  CAN ID: %i)", rec->bus_id, rec->can_id);
        return FALSE;
    }

    return TRUE;
}

static void
free_sender_receiver_config_cb(void *r) {
    sender_receiver_config_t *rec = (sender_receiver_config_t *)r;

    /* freeing result of g_strdup */
    g_free(rec->sender_name);
    rec->sender_name = NULL;
    g_free(rec->receiver_name);
    rec->receiver_name = NULL;
}

static guint64
sender_receiver_key(guint16 bus_id, guint32 can_id) {
    return ((guint64)bus_id << 32) | can_id;
}

static sender_receiver_config_t *
ht_lookup_sender_receiver_config(guint16 bus_id, guint32 can_id) {
    sender_receiver_config_t *tmp = NULL;
    guint64                   key = 0;

    if (sender_receiver_configs == NULL) {
        return NULL;
    }

    key = sender_receiver_key(bus_id, can_id);
    tmp = (sender_receiver_config_t *)g_hash_table_lookup(data_sender_receiver, &key);

    if (tmp == NULL) {
        key = sender_receiver_key(0, can_id);
        tmp = (sender_receiver_config_t *)g_hash_table_lookup(data_sender_receiver, &key);
    }

    return tmp;
}

static void
sender_receiver_free_key(gpointer key) {
    wmem_free(wmem_epan_scope(), key);
}

static void
post_update_sender_receiver_cb(void) {
    guint    i;
    guint64 *key_id = NULL;

    /* destroy old hash table, if it exist */
    if (data_sender_receiver) {
        g_hash_table_destroy(data_sender_receiver);
        data_sender_receiver = NULL;
    }

    /* create new hash table */
    data_sender_receiver = g_hash_table_new_full(g_int64_hash, g_int64_equal, &sender_receiver_free_key, NULL);

    if (data_sender_receiver == NULL || sender_receiver_configs == NULL || sender_receiver_config_num == 0) {
        return;
    }

    for (i = 0; i < sender_receiver_config_num; i++) {
        key_id = wmem_new(wmem_epan_scope(), guint64);
        *key_id = sender_receiver_key(sender_receiver_configs[i].bus_id, sender_receiver_configs[i].can_id);
        g_hash_table_insert(data_sender_receiver, key_id, &sender_receiver_configs[i]);
    }
}

gboolean
socketcan_set_source_and_destination_columns(packet_info *pinfo, can_info_t *caninfo) {
    sender_receiver_config_t *tmp = ht_lookup_sender_receiver_config(caninfo->bus_id, caninfo->id);

    if (tmp != NULL) {
        /* remove all addresses to support CAN as payload (e.g., TECMP) */
        clear_address(&pinfo->net_src);
        clear_address(&pinfo->dl_src);
        clear_address(&pinfo->src);
        clear_address(&pinfo->net_dst);
        clear_address(&pinfo->dl_dst);
        clear_address(&pinfo->dst);

        col_add_fstr(pinfo->cinfo, COL_DEF_SRC, "%s", tmp->sender_name);
        col_add_fstr(pinfo->cinfo, COL_DEF_DST, "%s", tmp->receiver_name);
        return true;
    }
    return false;
}

gboolean
socketcan_call_subdissectors(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, struct can_info *can_info, const gboolean use_heuristics_first) {
    dissector_table_t effective_can_id_dissector_table = (can_info->id & CAN_EFF_FLAG) ? can_extended_id_dissector_table : can_id_dissector_table;
    guint32 effective_can_id = (can_info->id & CAN_EFF_FLAG) ? can_info->id & CAN_EFF_MASK : can_info->id & CAN_SFF_MASK;

    if (!dissector_try_uint_new(effective_can_id_dissector_table, effective_can_id, tvb, pinfo, tree, TRUE, can_info)) {
        if (!use_heuristics_first) {
            if (!dissector_try_payload_new(subdissector_table, tvb, pinfo, tree, TRUE, can_info)) {
                if (!dissector_try_heuristic(heur_subdissector_list, tvb, pinfo, tree, &heur_dtbl_entry, can_info)) {
                    return FALSE;
                }
            }
        } else {
            if (!dissector_try_heuristic(heur_subdissector_list, tvb, pinfo, tree, &heur_dtbl_entry, can_info)) {
                if (!dissector_try_payload_new(subdissector_table, tvb, pinfo, tree, FALSE, can_info)) {
                    return FALSE;
                }
            }
        }
    }

    return TRUE;
}

/*
 * Either:
 *
 *    1) a given SocketCAN frame is known to contain a classic CAN
 *       packet based on information outside the SocketCAN header;
 *
 *    2) a given SocketCAN frame is known to contain a CAN FD
 *       packet based on information outside the SocketCAN header;
 *
 *    3) a given SocketCAN frame is known to contain a CAN XL
 *       packet based on information outside the SocketCAN header;
 *
 *    4) we don't know whether the given SocketCAN frame is a
 *       classic CAN packet, a CAN FD packet, or a CAN XL packet,
 *       and will have to check the CANXL_XLF bit in the "Frame Length"
 *       field and the CANFD_FDF bit in the "FD flags" field of the
 *       SocketCAN header to determine that.
 */
typedef enum {
    PACKET_TYPE_CAN,
    PACKET_TYPE_CAN_FD,
    PACKET_TYPE_CAN_XL,
    PACKET_TYPE_UNKNOWN
} can_packet_type_t;

static int
dissect_socketcan_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint encoding, guint xl_encoding, can_packet_type_t can_packet_type) {
    proto_tree     *can_tree;
    proto_item     *ti;
    guint8          frame_type;
    can_info_t      can_info;
    int * const    *can_flags_id;

    static int * const can_std_flags_id[] = {
        &hf_can_infoent_std,
        &hf_can_extflag,
        &hf_can_rtrflag,
        &hf_can_errflag,
        NULL,
    };
    static int * const can_ext_flags_id[] = {
        &hf_can_infoent_ext,
        &hf_can_extflag,
        &hf_can_rtrflag,
        &hf_can_errflag,
        NULL,
    };
    static int * const canfd_std_flags_id[] = {
        &hf_can_infoent_std,
        &hf_can_extflag,
        NULL,
    };
    static int * const canfd_ext_flags_id[] = {
        &hf_can_infoent_ext,
        &hf_can_extflag,
        NULL,
    };
    static int * const canfd_flag_fields[] = {
        &hf_canfd_brsflag,
        &hf_canfd_esiflag,
        NULL,
    };
    static int * const can_err_flags[] = {
        &hf_can_errflag,
        &hf_can_err_tx_timeout,
        &hf_can_err_lostarb,
        &hf_can_err_ctrl,
        &hf_can_err_prot,
        &hf_can_err_trx,
        &hf_can_err_ack,
        &hf_can_err_busoff,
        &hf_can_err_buserror,
        &hf_can_err_restarted,
        &hf_can_err_reserved,
        NULL,
    };
    static int * const canxl_prio_vcid_fields[] = {
        &hf_canxl_priority,
        &hf_canxl_vcid,
        NULL,
    };
    static int * const canxl_flag_fields[] = {
        &hf_canxl_secflag,
        NULL,
    };

    /*
     * If we weren't told the type of this frame, check
     * whether the CANFD_FDF flag is set in the FD flags
     * field of the header; if so, it's a CAN FD frame.
     * otherwise, it's a CAN frame.
     *
     * However, trust the CANFD_FDF flag only if the only
     * bits set in the FD flags field are the known bits,
     * and the two bytes following that field are both
     * zero.  This is because some older LINKTYPE_CAN_SOCKETCAN
     * frames had uninitialized junk in the FD flags field,
     * so we treat a frame with what appears to be uninitialized
     * junk as being CAN rather than CAN FD, under the assumption
     * that the CANFD_FDF bit is set because the field is
     * uninitialized, not because it was explicitly set because
     * it's a CAN FD frame.  At least some newer code that sets
     * that flag also makes sure that the fields in question are
     * initialized, so we assume that if they're not initialized
     * the code is older code that didn't support CAN FD.
     */
    if (can_packet_type == PACKET_TYPE_UNKNOWN) {
        guint8 frame_length;
        guint8 fd_flags;

        /*
         * Check whether the frame has the CANXL_XLF flag set in what
         * is in the location of the frame length field of a CAN classic
         * or CAN FD frame; if so, then it's a CAN XL frame (and that
         * field is the flags field of that frame).
         */
        frame_length = tvb_get_guint8(tvb, CAN_LEN_OFFSET);
        if (frame_length & CANXL_XLF) {
            can_packet_type = PACKET_TYPE_CAN_XL;
        } else {
            /*
             * This is a CAN classic or CAN FD frame.
             * Check whether the flags field has the CANFD_FDF
             * flag set, has no unknown flag bits set, and has
             * no bits set in the two reserved fields.  If so,
             * it's a CAN FD frame; otherwise, it's either a
             * CAN classic frame, or a frame where the CANFD_FDF
             * flag is set but where that might just be because
             * that field contains uninitialized junk rather
             * than because it's a CAN FD frame, so we treat it
             * as a CAN classic frame.
             */
            fd_flags = tvb_get_guint8(tvb, CANFD_FLAG_OFFSET);

            if ((fd_flags & CANFD_FDF) &&
                    ((fd_flags & ~(CANFD_BRS | CANFD_ESI | CANFD_FDF)) == 0) &&
                    tvb_get_guint8(tvb, CANFD_FLAG_OFFSET + 1) == 0 &&
                    tvb_get_guint8(tvb, CANFD_FLAG_OFFSET + 2) == 0) {
                can_packet_type = PACKET_TYPE_CAN_FD;
            } else {
                if (tvb_reported_length(tvb) == 72)
                    can_packet_type = PACKET_TYPE_CAN_FD;
                else
                    can_packet_type = PACKET_TYPE_CAN;
            }
        }
    }

    can_info.bus_id = get_bus_id(pinfo);

    if (can_packet_type == PACKET_TYPE_CAN_XL) {
        can_info.fd = CAN_TYPE_CAN_XL;
        col_set_str(pinfo->cinfo, COL_PROTOCOL, "CANXL");
        col_clear(pinfo->cinfo, COL_INFO);

        can_info.id = 0; /* XXX - is there an "ID" for XL frames? */

        ti = proto_tree_add_item(tree, proto_can, tvb, 0, -1, ENC_NA);
        proto_item_set_hidden(ti);
        ti = proto_tree_add_item(tree, proto_canxl, tvb, 0, -1, ENC_NA);
        can_tree = proto_item_add_subtree(ti, ett_can_xl);

        guint32 proto_vcid;

	/*
	 * The priority/VCID field is big-endian in LINKTYPE_CAN_SOCKETCAN
	 * captures, for historical reasons.  It's host-endian in
	 * Linux cooked captures.  This means we use the non-XL encoding.
	 */
        proto_tree_add_bitmask_list(can_tree, tvb, 0, 4, canxl_prio_vcid_fields, encoding);
        proto_vcid = tvb_get_guint32(tvb, 0, encoding);
        col_add_fstr(pinfo->cinfo, COL_INFO, "Priority: %u (0x%03x), VCID: %u (0x%02X)", proto_vcid & 0x7FF, proto_vcid & 0x7FF, (proto_vcid >> 16) & 0xFF, (proto_vcid >> 16) & 0xFF);
        proto_item_append_text(can_tree, ", Priority: %u (0x%03x), VCID: %u (0x%02X)", proto_vcid & 0x7FF, proto_vcid & 0x7FF, (proto_vcid >> 16) & 0xFF, (proto_vcid >> 16) & 0xFF);
        proto_tree_add_bitmask_list(can_tree, tvb, 4, 1, canxl_flag_fields, xl_encoding);

        socketcan_set_source_and_destination_columns(pinfo, &can_info);

        guint32 sdu_type;

	/*
	 * These fields are, if multi-byte, little-endian in
	 * LINKTYPE_CAN_SOCKETCAN captures, so use xl_encoding.
	 */
        proto_tree_add_item_ret_uint(can_tree, hf_canxl_sdu_type, tvb, 5, 1, ENC_NA, &sdu_type);
        proto_tree_add_item_ret_uint(can_tree, hf_canxl_len, tvb, CANXL_LEN_OFFSET, 2, xl_encoding, &can_info.len);
        col_append_fstr(pinfo->cinfo, COL_INFO, ", Length: %u", can_info.len);
        proto_item_append_text(can_tree, ", Length: %u", can_info.len);
        proto_tree_add_item(can_tree, hf_canxl_acceptance_field, tvb, CANXL_LEN_OFFSET+2, 4, xl_encoding);

        tvbuff_t   *next_tvb;

        next_tvb = tvb_new_subset_length(tvb, CANXL_DATA_OFFSET, can_info.len);

        if (!dissector_try_uint_new(canxl_sdu_type_dissector_table, sdu_type, next_tvb, pinfo, tree, TRUE, &can_info)) {
            call_data_dissector(next_tvb, pinfo, tree);
        }

        if (tvb_captured_length_remaining(tvb, CANXL_DATA_OFFSET+can_info.len) > 0) {
            proto_tree_add_item(can_tree, hf_can_padding, tvb, CANXL_DATA_OFFSET+can_info.len, -1, ENC_NA);
        }
    } else {
        if (can_packet_type == PACKET_TYPE_CAN_FD) {
            can_info.fd = CAN_TYPE_CAN_FD;
            col_set_str(pinfo->cinfo, COL_PROTOCOL, "CANFD");
        } else {
            can_info.fd = CAN_TYPE_CAN_CLASSIC;
            col_set_str(pinfo->cinfo, COL_PROTOCOL, "CAN");
        }
        col_clear(pinfo->cinfo, COL_INFO);

        ti = proto_tree_add_item(tree, proto_can, tvb, 0, -1, ENC_NA);
        if (can_packet_type == PACKET_TYPE_CAN_FD) {
            proto_item_set_hidden(ti);
            ti = proto_tree_add_item(tree, proto_canfd, tvb, 0, -1, ENC_NA);
        }
        can_tree = proto_item_add_subtree(ti, (can_packet_type == PACKET_TYPE_CAN_FD) ? ett_can_fd : ett_can);

        /* Get the ID and flags field */
        can_info.id = tvb_get_guint32(tvb, 0, encoding);

        /* Error Message Frames are only encapsulated in Classic CAN frames */
        if (can_packet_type == PACKET_TYPE_CAN && (can_info.id & CAN_ERR_FLAG)) {
            frame_type = LINUX_CAN_ERR;
            can_flags_id  = can_err_flags;
        } else if (can_info.id & CAN_EFF_FLAG) {
            frame_type = LINUX_CAN_EXT;
            can_info.id &= (CAN_EFF_MASK | CAN_FLAG_MASK);
            can_flags_id  = (can_packet_type == PACKET_TYPE_CAN_FD) ? canfd_ext_flags_id : can_ext_flags_id;
        } else {
            frame_type = LINUX_CAN_STD;
            can_info.id &= (CAN_SFF_MASK | CAN_FLAG_MASK);
            can_flags_id  = (can_packet_type == PACKET_TYPE_CAN_FD) ? canfd_std_flags_id : can_std_flags_id;
        }

        socketcan_set_source_and_destination_columns(pinfo, &can_info);

        proto_tree_add_bitmask_list(can_tree, tvb, 0, 4, can_flags_id, encoding);
        if (can_info.id & CAN_EFF_FLAG) {
            col_add_fstr(pinfo->cinfo, COL_INFO, "Ext. ID: %u (0x%08x)", can_info.id & CAN_EFF_MASK, can_info.id & CAN_EFF_MASK);
            proto_item_append_text(can_tree, ", Ext. ID: %u (0x%08x)", can_info.id & CAN_EFF_MASK, can_info.id & CAN_EFF_MASK);
        } else {
            col_add_fstr(pinfo->cinfo, COL_INFO, "ID: %u (0x%03x)", can_info.id & CAN_SFF_MASK, can_info.id & CAN_SFF_MASK);
            proto_item_append_text(can_tree, ", ID: %u (0x%03x)", can_info.id & CAN_SFF_MASK, can_info.id & CAN_SFF_MASK);
        }
        proto_tree_add_item_ret_uint(can_tree, hf_can_len, tvb, CAN_LEN_OFFSET, 1, ENC_NA, &can_info.len);
        col_append_fstr(pinfo->cinfo, COL_INFO, ", Length: %u", can_info.len);
        proto_item_append_text(can_tree, ", Length: %u", can_info.len);

        if (frame_type == LINUX_CAN_ERR && can_info.len != CAN_ERR_DLC) {
            proto_tree_add_expert(tree, pinfo, &ei_can_err_dlc_mismatch, tvb, CAN_LEN_OFFSET, 1);
        }

        if (can_packet_type == PACKET_TYPE_CAN_FD) {
            proto_tree_add_bitmask_list(can_tree, tvb, CANFD_FLAG_OFFSET, 1, canfd_flag_fields, ENC_NA);
            proto_tree_add_item(can_tree, hf_can_reserved, tvb, CANFD_FLAG_OFFSET+1, 2, ENC_NA);
        } else {
            proto_tree_add_item(can_tree, hf_can_reserved, tvb, CANFD_FLAG_OFFSET, 3, ENC_NA);
        }

        if (frame_type == LINUX_CAN_ERR) {
            int * const *flag;
            const char *sepa = ": ";

            col_set_str(pinfo->cinfo, COL_INFO, "ERR");

            for (flag = can_err_flags; *flag; flag++) {
                header_field_info *hfi;

                hfi = proto_registrar_get_nth(**flag);
                if (!hfi)
                    continue;

                if ((can_info.id & hfi->bitmask & ~CAN_FLAG_MASK) == 0)
                    continue;

                col_append_sep_str(pinfo->cinfo, COL_INFO, sepa, hfi->name);
                sepa = ", ";
            }

            if (can_info.id & CAN_ERR_LOSTARB) {
                proto_tree_add_item(can_tree, hf_can_err_lostarb_bit_number, tvb, CAN_DATA_OFFSET + 0, 1, ENC_NA);
            }

            if (can_info.id & CAN_ERR_CTRL) {
                static int * const can_err_ctrl_flags[] = {
                    &hf_can_err_ctrl_rx_overflow,
                    &hf_can_err_ctrl_tx_overflow,
                    &hf_can_err_ctrl_rx_warning,
                    &hf_can_err_ctrl_tx_warning,
                    &hf_can_err_ctrl_rx_passive,
                    &hf_can_err_ctrl_tx_passive,
                    &hf_can_err_ctrl_active,
                    NULL,
                };

                proto_tree_add_bitmask_list(can_tree, tvb, CAN_DATA_OFFSET+1, 1, can_err_ctrl_flags, ENC_NA);
           }

           if (can_info.id & CAN_ERR_PROT) {
                static int * const can_err_prot_error_type_flags[] = {
                    &hf_can_err_prot_error_type_bit,
                    &hf_can_err_prot_error_type_form,
                    &hf_can_err_prot_error_type_stuff,
                    &hf_can_err_prot_error_type_bit0,
                    &hf_can_err_prot_error_type_bit1,
                    &hf_can_err_prot_error_type_overload,
                    &hf_can_err_prot_error_type_active,
                    &hf_can_err_prot_error_type_tx,
                    NULL
                };
                proto_tree_add_bitmask_list(can_tree, tvb, CAN_DATA_OFFSET+2, 1, can_err_prot_error_type_flags, ENC_NA);
                proto_tree_add_item(can_tree, hf_can_err_prot_error_location, tvb, CAN_DATA_OFFSET+3, 1, ENC_NA);
            }

            if (can_info.id & CAN_ERR_TRX) {
                proto_tree_add_item(can_tree, hf_can_err_trx_canh, tvb, CAN_DATA_OFFSET+4, 1, ENC_NA);
                proto_tree_add_item(can_tree, hf_can_err_trx_canl, tvb, CAN_DATA_OFFSET+4, 1, ENC_NA);
            }

            proto_tree_add_item(can_tree, hf_can_err_ctrl_specific, tvb, CAN_DATA_OFFSET+5, 3, ENC_NA);
        } else {
            tvbuff_t   *next_tvb;

            if (can_info.id & CAN_RTR_FLAG) {
                col_append_str(pinfo->cinfo, COL_INFO, "(Remote Transmission Request)");
            }

            next_tvb = tvb_new_subset_length(tvb, CAN_DATA_OFFSET, can_info.len);

            if (!socketcan_call_subdissectors(next_tvb, pinfo, tree, &can_info, heuristic_first)) {
                call_data_dissector(next_tvb, pinfo, tree);
           }
        }

        if (tvb_captured_length_remaining(tvb, CAN_DATA_OFFSET+can_info.len) > 0) {
            proto_tree_add_item(can_tree, hf_can_padding, tvb, CAN_DATA_OFFSET+can_info.len, -1, ENC_NA);
        }
    }

    return tvb_captured_length(tvb);
}

static int
dissect_socketcan_bigendian(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {
    return dissect_socketcan_common(tvb, pinfo, tree,
                                    byte_swap ? ENC_LITTLE_ENDIAN : ENC_BIG_ENDIAN,
                                    ENC_LITTLE_ENDIAN,
                                    PACKET_TYPE_UNKNOWN);
}

static int
dissect_socketcan_classic(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {
    return dissect_socketcan_common(tvb, pinfo, tree,
                                    byte_swap ? ENC_ANTI_HOST_ENDIAN : ENC_HOST_ENDIAN,
                                    ENC_HOST_ENDIAN, /* Not used, as this is CAN classic, not CAN XL */
                                    PACKET_TYPE_CAN);
}

static int
dissect_socketcan_fd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {
    return dissect_socketcan_common(tvb, pinfo, tree,
                                    byte_swap ? ENC_ANTI_HOST_ENDIAN : ENC_HOST_ENDIAN,
                                    ENC_HOST_ENDIAN, /* Not used, as this is CAN FD, not CAN XL */
                                    PACKET_TYPE_CAN_FD);
}

static int
dissect_socketcan_xl(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {
    return dissect_socketcan_common(tvb, pinfo, tree,
                                    byte_swap ? ENC_ANTI_HOST_ENDIAN : ENC_HOST_ENDIAN,
                                    ENC_HOST_ENDIAN,
                                    PACKET_TYPE_CAN_XL);
}

void
proto_register_socketcan(void) {
    static hf_register_info hf[] = {
        { &hf_can_infoent_ext, {
            "ID", "can.id", FT_UINT32, BASE_DEC_HEX, NULL, CAN_EFF_MASK, NULL, HFILL } },
        { &hf_can_infoent_std, {
            "ID", "can.id", FT_UINT32, BASE_DEC_HEX, NULL, CAN_SFF_MASK, NULL, HFILL } },
        { &hf_can_extflag, {
            "Extended Flag", "can.flags.xtd", FT_BOOLEAN, 32, NULL, CAN_EFF_FLAG, NULL, HFILL } },
        { &hf_can_rtrflag, {
            "Remote Transmission Request Flag", "can.flags.rtr", FT_BOOLEAN, 32, NULL, CAN_RTR_FLAG, NULL, HFILL } },
        { &hf_can_errflag, {
            "Error Message Flag", "can.flags.err", FT_BOOLEAN, 32, NULL, CAN_ERR_FLAG, NULL, HFILL } },
        { &hf_can_len, {
            "Frame-Length", "can.len", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } },
        { &hf_can_reserved, {
            "Reserved", "can.reserved", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } },
        { &hf_can_padding, {
            "Padding", "can.padding", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } },
        { &hf_canfd_brsflag, {
            "Bit Rate Setting", "canfd.flags.brs", FT_BOOLEAN, 8, NULL, CANFD_BRS, NULL, HFILL } },
        { &hf_canfd_esiflag, {
            "Error State Indicator", "canfd.flags.esi", FT_BOOLEAN, 8, NULL, CANFD_ESI, NULL, HFILL } },
        { &hf_can_err_tx_timeout, {
            "Transmit timeout", "can.err.tx_timeout", FT_BOOLEAN, 32, NULL, CAN_ERR_TX_TIMEOUT, NULL, HFILL } },
        { &hf_can_err_lostarb, {
            "Lost arbitration", "can.err.lostarb", FT_BOOLEAN, 32, NULL, CAN_ERR_LOSTARB, NULL, HFILL } },
        { &hf_can_err_ctrl, {
            "Controller problems", "can.err.ctrl", FT_BOOLEAN, 32, NULL, CAN_ERR_CTRL, NULL, HFILL } },
        { &hf_can_err_prot, {
            "Protocol violation", "can.err.prot", FT_BOOLEAN, 32, NULL, CAN_ERR_PROT, NULL, HFILL } },
        { &hf_can_err_trx, {
            "Transceiver status", "can.err.trx", FT_BOOLEAN, 32, NULL, CAN_ERR_TRX, NULL, HFILL } },
        { &hf_can_err_ack, {
            "No acknowledgment", "can.err.ack", FT_BOOLEAN, 32, NULL, CAN_ERR_ACK, NULL, HFILL } },
        { &hf_can_err_busoff, {
            "Bus off", "can.err.busoff", FT_BOOLEAN, 32, NULL, CAN_ERR_BUSOFF, NULL, HFILL } },
        { &hf_can_err_buserror, {
            "Bus error", "can.err.buserror", FT_BOOLEAN, 32, NULL, CAN_ERR_BUSERROR, NULL, HFILL } },
        { &hf_can_err_restarted, {
            "Controller restarted", "can.err.restarted", FT_BOOLEAN, 32, NULL, CAN_ERR_RESTARTED, NULL, HFILL } },
        { &hf_can_err_reserved, {
            "Reserved", "can.err.reserved", FT_UINT32, BASE_HEX, NULL, CAN_ERR_RESERVED, NULL, HFILL } },
        { &hf_can_err_lostarb_bit_number, {
            "Lost arbitration in bit number", "can.err.lostarb.bitnum", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } },
        { &hf_can_err_ctrl_rx_overflow, {
            "RX buffer overflow", "can.err.ctrl.rx_overflow", FT_BOOLEAN, 8, NULL, 0x01, NULL, HFILL } },
        { &hf_can_err_ctrl_tx_overflow, {
            "TX buffer overflow", "can.err.ctrl.tx_overflow", FT_BOOLEAN, 8, NULL, 0x02, NULL, HFILL } },
        { &hf_can_err_ctrl_rx_warning, {
            "Reached warning level for RX errors", "can.err.ctrl.rx_warning", FT_BOOLEAN, 8, NULL, 0x04, NULL, HFILL } },
        { &hf_can_err_ctrl_tx_warning, {
            "Reached warning level for TX errors", "can.err.ctrl.tx_warning", FT_BOOLEAN, 8, NULL, 0x08, NULL, HFILL } },
        { &hf_can_err_ctrl_rx_passive, {
            "Reached error passive status RX", "can.err.ctrl.rx_passive", FT_BOOLEAN, 8, NULL, 0x10, NULL, HFILL } },
        { &hf_can_err_ctrl_tx_passive, {
            "Reached error passive status TX", "can.err.ctrl.tx_passive", FT_BOOLEAN, 8, NULL, 0x20, NULL, HFILL } },
        { &hf_can_err_ctrl_active, {
            "Recovered to error active state", "can.err.ctrl.active", FT_BOOLEAN, 8, NULL, 0x40, NULL, HFILL } },
        { &hf_can_err_prot_error_type_bit, {
            "Single bit error", "can.err.prot.type.bit", FT_BOOLEAN, 8, NULL, CAN_ERR_PROT_BIT, NULL, HFILL } },
        { &hf_can_err_prot_error_type_form, {
            "Frame format error", "can.err.prot.type.form", FT_BOOLEAN, 8, NULL, CAN_ERR_PROT_FORM, NULL, HFILL } },
        { &hf_can_err_prot_error_type_stuff, {
            "Bit stuffing error", "can.err.prot.type.stuff", FT_BOOLEAN, 8, NULL, CAN_ERR_PROT_STUFF, NULL, HFILL } },
        { &hf_can_err_prot_error_type_bit0, {
            "Unable to send dominant bit", "can.err.prot.type.bit0", FT_BOOLEAN, 8, NULL, CAN_ERR_PROT_BIT0, NULL, HFILL } },
        { &hf_can_err_prot_error_type_bit1, {
            "Unable to send recessive bit", "can.err.prot.type.bit1", FT_BOOLEAN, 8, NULL, CAN_ERR_PROT_BIT1, NULL, HFILL } },
        { &hf_can_err_prot_error_type_overload, {
            "Bus overload", "can.err.prot.type.overload", FT_BOOLEAN, 8, NULL, CAN_ERR_PROT_OVERLOAD, NULL, HFILL } },
        { &hf_can_err_prot_error_type_active, {
            "Active error announcement", "can.err.prot.type.active", FT_BOOLEAN, 8, NULL, CAN_ERR_PROT_ACTIVE, NULL, HFILL } },
        { &hf_can_err_prot_error_type_tx, {
            "Error occurred on transmission", "can.err.prot.type.tx", FT_BOOLEAN, 8, NULL, CAN_ERR_PROT_TX, NULL, HFILL } },
        { &hf_can_err_prot_error_location, {
            "Protocol error location", "can.err.prot.location", FT_UINT8, BASE_DEC, VALS(can_err_prot_error_location_vals), 0, NULL, HFILL } },
        { &hf_can_err_trx_canh, {
            "Transceiver CANH status", "can.err.trx.canh", FT_UINT8, BASE_DEC, VALS(can_err_trx_canh_vals), 0x0F, NULL, HFILL } },
        { &hf_can_err_trx_canl, {
            "Transceiver CANL status", "can.err.trx.canl", FT_UINT8, BASE_DEC, VALS(can_err_trx_canl_vals), 0xF0, NULL, HFILL } },
        { &hf_can_err_ctrl_specific, {
            "Controller specific data", "can.err.ctrl_specific", FT_BYTES, SEP_SPACE, NULL, 0, NULL, HFILL } },
        { &hf_canxl_priority, {
            "Priority", "canxl.priority", FT_UINT32, BASE_DEC, NULL, 0x0000FFFF, NULL, HFILL } },
        { &hf_canxl_vcid, {
            "VCID", "canxl.vcid", FT_UINT32, BASE_DEC, NULL, 0x00FF0000, NULL, HFILL } },
        { &hf_canxl_secflag, {
            "Simple Extended Context", "canxl.flags.sec", FT_BOOLEAN, 8, NULL, CANXL_SEC, NULL, HFILL } },
        { &hf_canxl_sdu_type, {
            "SDU type", "canxl.sdu_type", FT_UINT8, BASE_HEX, VALS(canxl_sdu_type_vals), 0, NULL, HFILL } },
        { &hf_canxl_len, {
            "Frame-Length", "canxl.len", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } },
        { &hf_canxl_acceptance_field, {
            "Acceptance field", "canxl.acceptance_field", FT_UINT32, BASE_DEC_HEX, NULL, 0, NULL, HFILL } },
    };

    uat_t *can_interface_uat = NULL;
    uat_t *sender_receiver_uat = NULL;

    /* Setup protocol subtree array */
    static gint *ett[] = {
        &ett_can,
        &ett_can_fd,
        &ett_can_xl
    };

    static ei_register_info ei[] = {
        { &ei_can_err_dlc_mismatch, {
            "can.err.dlc_mismatch", PI_MALFORMED, PI_ERROR, "ERROR: DLC mismatch", EXPFILL } }
    };

    module_t *can_module;

    proto_can = proto_register_protocol("Controller Area Network", "CAN", "can");

    /*
     * "can-hostendian" is a legacy name (there never was, in any libpcap
     * release, a SocketCAN LINKTYPE_ value for a host-endian CAN ID
     * and flags field); we need to keep it around in case some candump
     * or Busmaster capture that was saved as a pcap or pcapng file,
     * as those use a linktype of LINKTYPE_WIRESHARK_UPPER_PDU with
     * "can-hostendian" as the dissector name.
     *
     * "can-bigendian" is also a legacy name (fpr CAN XL frames, the
     * fields in the header are in *little-endian* order); we keep it
     * around for the same reason.  It's used for the dissector for
     * LINKTYPE_CAN_SOCKETCAN.
     */
    socketcan_classic_handle = register_dissector("can-hostendian", dissect_socketcan_classic, proto_can);
    socketcan_bigendian_handle = register_dissector("can-bigendian", dissect_socketcan_bigendian, proto_can);

    proto_canfd = proto_register_protocol("Controller Area Network FD", "CANFD", "canfd");
    socketcan_fd_handle = register_dissector("canfd", dissect_socketcan_fd, proto_canfd);

    proto_canxl = proto_register_protocol("Controller Area Network XL", "CANXL", "canxl");
    socketcan_xl_handle = register_dissector("canxl", dissect_socketcan_xl, proto_canxl);

    proto_register_field_array(proto_can, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));

    expert_register_field_array(expert_register_protocol(proto_can), ei, array_length(ei));

    can_module = prefs_register_protocol(proto_can, NULL);

    prefs_register_obsolete_preference(can_module, "protocol");

    prefs_register_bool_preference(can_module, "byte_swap", "Byte-swap the CAN ID/flags field",
        "Whether the CAN ID/flags field should be byte-swapped in CAN classic and CAN FD packets",
        &byte_swap);

    prefs_register_bool_preference(can_module, "try_heuristic_first", "Try heuristic sub-dissectors first",
        "Try to decode a packet using an heuristic sub-dissector before using a sub-dissector registered to \"decode as\"",
        &heuristic_first);

    can_id_dissector_table = register_dissector_table("can.id", "CAN ID", proto_can, FT_UINT32, BASE_DEC);

    can_extended_id_dissector_table = register_dissector_table("can.extended_id", "CAN Extended ID", proto_can, FT_UINT32, BASE_DEC);

    subdissector_table = register_decode_as_next_proto(proto_can, "can.subdissector", "CAN next level dissector", NULL);

    canxl_sdu_type_dissector_table = register_dissector_table("canxl.sdu_type", "CAN XL SDU type",  proto_canxl, FT_UINT8, BASE_HEX);

    heur_subdissector_list = register_heur_dissector_list_with_description("can", "CAN heuristic", proto_can);

    static uat_field_t can_interface_mapping_uat_fields[] = {
        UAT_FLD_HEX(interface_configs,      interface_id,   "Interface ID",   "ID of the Interface with 0xffffffff = any (hex uint32 without leading 0x)"),
        UAT_FLD_CSTRING(interface_configs,  interface_name, "Interface Name", "Name of the Interface, empty = any (string)"),
        UAT_FLD_HEX(interface_configs,      bus_id,         "Bus ID",         "Bus ID of the Interface (hex uint16 without leading 0x)"),
        UAT_END_FIELDS
    };

    can_interface_uat = uat_new("CAN Interface Mapping",
        sizeof(interface_config_t),         /* record size           */
        DATAFILE_CAN_INTERFACE_MAPPING,     /* filename              */
        TRUE,                               /* from profile          */
        (void**)&interface_configs,         /* data_ptr              */
        &interface_config_num,              /* numitems_ptr          */
        UAT_AFFECTS_DISSECTION,             /* but not fields        */
        NULL,                               /* help                  */
        copy_interface_config_cb,           /* copy callback         */
        update_interface_config,            /* update callback       */
        free_interface_config_cb,           /* free callback         */
        post_update_can_interfaces_cb,      /* post update callback  */
        NULL,                               /* reset callback        */
        can_interface_mapping_uat_fields    /* UAT field definitions */
    );

    prefs_register_uat_preference(can_module, "_can_interface_mapping", "Interface Mapping",
        "A table to define the mapping between interface and Bus ID.", can_interface_uat);

    static uat_field_t sender_receiver_mapping_uat_fields[] = {
        UAT_FLD_HEX(sender_receiver_configs,     bus_id,        "Bus ID",        "Bus ID of the Interface with 0 meaning any (hex uint16 without leading 0x)."),
        UAT_FLD_HEX(sender_receiver_configs,     can_id,        "CAN ID",        "ID of the CAN Message (hex uint32 without leading 0x)"),
        UAT_FLD_CSTRING(sender_receiver_configs, sender_name,   "Sender Name",   "Name of Sender(s)"),
        UAT_FLD_CSTRING(sender_receiver_configs, receiver_name, "Receiver Name", "Name of Receiver(s)"),
        UAT_END_FIELDS
    };

    sender_receiver_uat = uat_new("Sender Receiver Config",
        sizeof(sender_receiver_config_t),   /* record size           */
        DATAFILE_CAN_SENDER_RECEIVER,       /* filename              */
        TRUE,                               /* from profile          */
        (void**)&sender_receiver_configs,   /* data_ptr              */
        &sender_receiver_config_num,        /* numitems_ptr          */
        UAT_AFFECTS_DISSECTION,             /* but not fields        */
        NULL,                               /* help                  */
        copy_sender_receiver_config_cb,     /* copy callback         */
        update_sender_receiver_config,      /* update callback       */
        free_sender_receiver_config_cb,     /* free callback         */
        post_update_sender_receiver_cb,     /* post update callback  */
        NULL,                               /* reset callback        */
        sender_receiver_mapping_uat_fields  /* UAT field definitions */
    );

    prefs_register_uat_preference(can_module, "_sender_receiver_config", "Sender Receiver Config",
        "A table to define the mapping between Bus ID and CAN ID to Sender and Receiver.", sender_receiver_uat);
}

void
proto_reg_handoff_socketcan(void) {
    dissector_add_uint("wtap_encap", WTAP_ENCAP_SOCKETCAN, socketcan_bigendian_handle);

    dissector_add_uint("sll.ltype", LINUX_SLL_P_CAN, socketcan_classic_handle);
    dissector_add_uint("sll.ltype", LINUX_SLL_P_CANFD, socketcan_fd_handle);
    dissector_add_uint("sll.ltype", LINUX_SLL_P_CANXL, socketcan_xl_handle);
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * vi: set shiftwidth=4 tabstop=8 expandtab:
 * :indentSize=4:tabSize=8:noTabs=true:
 */