summaryrefslogtreecommitdiffstats
path: root/epan/dissectors/packet-dec-dnart.c
blob: bc6f82b2991258c4b069f4c95e04399d37b6e9d5 (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
/* packet-dec-dnart.c
 *
 * Routines for DECnet NSP/RT  disassembly
 *
 * Copyright 2003-2005 Philips Medical Systems
 * Copyright 2003-2005 Fred Hoekstra, Philips Medical Systems.
 *                (fred.hoekstra@philips.com)
 *
 * Use was made of the following documentation:
 *
 *         DECnet DIGITAL Network Architecture
 *      Routing Layer Functional Specification
 *      Version 2.0.0 May, 1983
 *
 *         DECnet DIGITAL Network Architecture
 *      NSP Functional Specification
 *      Phase IV, Version 4.0.1, July 1984
 *
 *      DNA FS SESSION CONTROL
 *      SECON.RNO [31,1]
 *      EDITED 10/17/80
 *
 * See
 *
 *    http://h71000.www7.hp.com/wizard/decnet/
 *
 * for some DECnet specifications.
 *
 * 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/etypes.h>
#include <epan/expert.h>
#include <epan/ppptypes.h>

typedef enum {
    RT_CTL_INITIALIZATION,
    RT_CTL_VERIFICATION,
    RT_CTL_HELLO_TEST,
    RT_CTL_LVL1_ROUTING,
    RT_CTL_LVL2_ROUTING,
    RT_CTL_ETH_ROUTER_HELLO_MSG,
    RT_CTL_ETH_ENDNODE_HELLO_MSG
} ctl_msg_types;

#define DEC_RT_SIZE        27

#define DATA_SEGMENT_MSG     0x00 /* "Data segment" */
#define LINK_SERVICE_MSG     0x10 /* "Link service message" */
#define BOM_MSG              0x20 /* "Beginning of segment (BOM)message" */
#define EOM_MSG              0x40 /* "End of segment (EOM)message" */
#define BOM_EOM_MSG          0x60 /* "BOM / EOM message" */
#define INTERRUPT_MSG        0x30 /* "Interrupt message" */
#define DATA_ACK_MSG         0x04 /* "Data acknowledgement message" */
#define OTHER_DATA_ACK_MSG   0x14 /* "Other data acknowledgement message" */
#define CONN_ACK_MSG         0x24 /* "Connect acknowledgement message" */
#define NOP_MSG              0x08 /* "NOP" */
#define CONN_INITIATE_MSG    0x18 /* "Connect initiate" */
#define CONN_CONFIRM_MSG     0x28 /* "Connect confirm" */
#define DISCONN_INITIATE_MSG 0x38 /* "Disconnect initiate" */
#define DISCONN_CONFIRM_MSG  0x48 /* "Disconnect confirm" */
#define RE_XMT_CONN_INIT_MSG 0x68 /* "Retransmitted connect initiate" */

/* Flag bits */

#define RT_FLAGS_CTRL_MSG      0x01
#define RT_FLAGS_LONG_MSG      0x04 /* Actually: 0x06->long, 0x02->short*/
#define RT_FLAGS_RQR           0x08
#define RT_FLAGS_RTS           0x10
#define RT_FLAGS_INTRA_ETHER   0x20
#define RT_FLAGS_DISCARD       0x40
#define RT_FLAGS_PAD           0x80

void proto_register_dec_rt(void);
void proto_reg_handoff_dec_rt(void);

static dissector_handle_t dec_rt_handle;

static int proto_dec_rt = -1;

static int hf_dec_routing_flags = -1;
static int hf_dec_rt_ctrl_msg = -1;
static int hf_dec_rt_long_msg = -1;
static int hf_dec_rt_short_msg = -1;
static int hf_dec_rt_rqr = -1;
static int hf_dec_rt_rts = -1;
static int hf_dec_rt_inter_eth = -1;
static int hf_dec_rt_discard = -1;
static int hf_dec_rt_dst_addr = -1;
static int hf_dec_rt_src_addr = -1;
static int hf_dec_rt_nl2 = -1;
static int hf_dec_rt_service_class = -1;
static int hf_dec_rt_protocol_type = -1;
static int hf_dec_rt_visit_count = -1;
static int hf_dec_rt_dst_node = -1;
static int hf_dec_rt_src_node = -1;
/* Routing control messages */
static int hf_dec_rt_visited_nodes = -1;
static int hf_dec_ctl_msgs = -1;
static int hf_dec_ctl_msg_hdr = -1;
static int hf_dec_nsp_msgs = -1;
static int hf_dec_rt_tiinfo = -1;
static int hf_dec_rt_blk_size = -1;
static int hf_dec_rt_version = -1;
static int hf_dec_rt_timer = -1;
static int hf_dec_rt_reserved = -1;
static int hf_dec_rt_fcnval = -1;
static int hf_dec_rt_test_data = -1;
static int hf_dec_rt_segment = -1;
static int hf_dec_rt_checksum = -1;
static int hf_dec_rt_checksum_status = -1;
static int hf_dec_rt_id = -1;
static int hf_dec_rt_iinfo = -1;
static int hf_dec_rt_iinfo_node_type = -1;
static int hf_dec_rt_iinfo_vrf = -1;
static int hf_dec_rt_iinfo_rej = -1;
static int hf_dec_rt_iinfo_verf = -1;
static int hf_dec_rt_iinfo_mta = -1;
static int hf_dec_rt_iinfo_blkreq = -1;
static int hf_dec_rt_iprio = -1;
static int hf_dec_rt_neighbor = -1;
static int hf_dec_rt_seed = -1;
static int hf_dec_rt_elist = -1;
static int hf_dec_rt_ename = -1;
static int hf_dec_rt_router_id = -1;
static int hf_dec_rt_router_state = -1;
static int hf_dec_rt_router_prio = -1;
static int hf_dec_rt_seg_size = -1;
static int hf_dec_rt_acknum = -1;
static int hf_dec_rt_segnum = -1;
static int hf_dec_rt_delay = -1;
static int hf_dec_flow_control = -1;
static int hf_dec_rt_fc_val = -1;
static int hf_dec_rt_services = -1;
static int hf_dec_rt_info = -1;
static int hf_dec_disc_reason = -1;
static int hf_dec_conn_contents = -1;
static int hf_dec_sess_obj_type = -1;
static int hf_dec_sess_grp_code = -1;
static int hf_dec_sess_usr_code = -1;
static int hf_dec_sess_dst_name = -1;
static int hf_dec_sess_src_name = -1;
static int hf_dec_sess_menu_ver = -1;
static int hf_dec_sess_rqstr_id = -1;

static gint ett_dec_rt = -1;
static gint ett_dec_routing_flags = -1;
static gint ett_dec_msg_flags = -1;
static gint ett_dec_rt_ctl_msg = -1;
static gint ett_dec_rt_nsp_msg = -1;
static gint ett_dec_rt_info_flags = -1;
static gint ett_dec_rt_list = -1;
static gint ett_dec_rt_rlist = -1;
static gint ett_dec_rt_state = -1;
static gint ett_dec_flow_control = -1;
static gint ett_dec_sess_contents = -1;

static expert_field ei_dec_rt_checksum = EI_INIT;

static gint dec_dna_total_bytes_this_segment = 0;
static gint dec_dna_previous_total = 0;

static const value_string rt_msg_type_vals[] = {
    { 0x0   , "Initialization message" },
    { 0x1   , "Verification message" },
    { 0x2   , "Hello and test message" },
    { 0x3   , "Level 1 routing message" },
    { 0x4   , "Level 2 routing message" },
    { 0x5   , "Ethernet router hello message" },
    { 0x6   , "Ethernet endnode hello message" },
    { 0,    NULL }
};

static const value_string nsp_msg_type_vals[] = {
    { 0x00   , "Data segment continuation" },
    { 0x04   , "Data acknowledgement message" },
    { 0x08   , "NOP" },
    { 0x10   , "Link service message" },
    { 0x14   , "Other data acknowledgement message" },
    { 0x18   , "Connect initiate" },
    { 0x20   , "Beginning of segment message" },
    { 0x24   , "Connect acknowledgement message" },
    { 0x28   , "Connect confirm" },
    { 0x30   , "Interrupt message" },
    { 0x38   , "Disconnect initiate" },
    { 0x40   , "End of segment message" },
    { 0x48   , "Disconnect confirm" },
    { 0x60   , "Begin of segment / End of segment" },
    { 0x68   , "Retransmitted connect initiate" },
    { 0,    NULL }
};

static const value_string rt_tiinfo_vals[] = {
    {0x01,  "Level 2 router"},
    {0x02,  "Level 1 router"},
    {0x03,  "End node"},
    {0x04,  "Routing layer verification required"},
    {0x08,  "Blocking requested"},
    {0x0,  NULL}
};

static const value_string rt_iinfo_node_type_vals[] = {
    {0x01,  "Level 2 router"},
    {0x02,  "Level 1 router"},
    {0x03,  "End node"},
    {0x0,  NULL}
};

static const value_string rt_flow_control_vals[] = {
    {0x00,  "no change"},
    {0x01,  "do not send data"},
    {0x02,  "send data"},
    {0x03,  "reserved"},
    {0x0,  NULL}
};

static const value_string rt_services_vals[] = {
    {0x00,  "none"},
    {0x04,  "segment request count"},
    {0x08,  "Session control message request count"},
    {0x0c,  "reserved"},
    {0x0,   NULL}
};

static const value_string rt_info_version_vals[] = {
    {0x00,  "version 3.2"},
    {0x01,  "version 3.1"},
    {0x02,  "version 4.0"},
    {0x03,   "reserved"},
    {0x0,   NULL}
};

static const value_string rt_disc_reason_vals[] = {
    { 0,    "no error"},
    { 3,    "The node is shutting down"},
    { 4,    "The destination end user does not exist"},
    { 5,    "A connect message contains an invalid end user name"},
    { 6,    "Destination end user has insufficient resources"},
    { 7,    "Unspecified error"},
    { 8,    "A third party has disconnected the link"},
    { 9,    "An end user has aborted the logical link"},
    { 32,   "The node has insufficient resources"},
    { 33,   "Destination end user has insufficient resources"},
    { 34,   "Connect request rejected because incorrect RQSTRID or PASSWORD"},
    { 36,   "Connect request rejected because of unacceptable ACCOUNT info"},
    { 38,   "End user has timed out, aborted or cancelled a connect request"},
    { 43,   "Connect request RQSTRID, PASSWORD, ACCOUNT or USRDATA too long"},
    { 0,    NULL}
};

#define RT_TYPE_TOPOLOGY_CHANGE    2
#define RT_TYPE_HELLO            25

#if ! defined true
#define true 1
#endif
#if ! defined false
#define false 0
#endif

static int
handle_nsp_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *tree,
    guint offset,
    guint8 nsp_msg_type);


static int
do_initialization_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *ctl_msg_tree,
    guint offset);

static int
do_verification_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *ctl_msg_tree,
    guint offset);

static int
do_hello_test_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *ctl_msg_tree,
    guint offset);

static int
do_routing_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *ctl_msg_tree,
    guint offset,
    guint msg);

static int
do_hello_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *ctl_msg_tree,
    guint offset,
    guint msg);

static int
handle_connect_contents(
    tvbuff_t *tvb,
    proto_tree *tree,
    guint offset);

static int
handle_disc_init_contents(
    guint offset);

static char *
dnet_ntoa(wmem_allocator_t *pool, const guint8 *data)
{
    if (data[0] == 0xAA && data[1] == 0x00 && data[2] == 0x04 && data[3] == 0x00) {
        guint16 dnet_addr = data[4] | (data[5] << 8);
        return wmem_strdup_printf(pool, "%d.%d", dnet_addr >> 10, dnet_addr & 0x03FF);
    }
    return NULL;
}

static void
set_dnet_address(packet_info *pinfo, address *paddr_src, address *paddr_tgt)
{
    if (paddr_tgt->type != AT_STRINGZ && paddr_src->type == AT_ETHER) {
        char *addr = dnet_ntoa(pinfo->pool, (const guint8 *)paddr_src->data);
        if (addr != NULL)
            set_address(paddr_tgt, AT_STRINGZ, 1,
                    wmem_strdup(pinfo->pool, addr));
    }
}

static int
dissect_dec_rt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
    guint8  padding_length;
    guint8  forward;
    guint8  msg_flags;
    guint   rt_visit_count, rt_zero = 0;
    gint    offset;
    proto_tree *rt_tree;
    proto_tree *flags_tree;
    proto_item *ti;
    char *addr;

    offset = 0;
    col_set_str(pinfo->cinfo, COL_PROTOCOL, "DEC DNA");
    col_clear(pinfo->cinfo, COL_INFO);

    set_dnet_address(pinfo, &pinfo->dl_src, &pinfo->net_src);
    set_dnet_address(pinfo, &pinfo->dl_src, &pinfo->src);
    set_dnet_address(pinfo, &pinfo->dl_dst, &pinfo->net_dst);
    set_dnet_address(pinfo, &pinfo->dl_dst, &pinfo->dst);

    offset += 2;
    msg_flags = tvb_get_guint8(tvb, offset);
    ti = proto_tree_add_item(tree, proto_dec_rt, tvb, 0, -1, ENC_NA);
    rt_tree = proto_item_add_subtree(ti, ett_dec_rt);
    /* When padding, the first byte after the padding has
       the real routing flags */
    if (msg_flags & 0x80) {
        /* There is padding present, skip it */
        padding_length = msg_flags & 0x7f;
        offset += padding_length;
    }

    /* The real routing flag */
    msg_flags = tvb_get_guint8(tvb, offset);
    ti = proto_tree_add_uint(rt_tree, hf_dec_routing_flags, tvb,
                    offset, 1, msg_flags);
    flags_tree = proto_item_add_subtree(ti, ett_dec_routing_flags);

    if (msg_flags & RT_FLAGS_CTRL_MSG) {
        guint8  ctl_msg_type;
        proto_tree *ctl_msg_tree;

        ctl_msg_type = (msg_flags >> 1) & 0x7;
        proto_tree_add_boolean(flags_tree, hf_dec_rt_ctrl_msg, tvb, offset, 1,
            msg_flags);
        proto_tree_add_uint(flags_tree, hf_dec_ctl_msgs, tvb, offset, 1,
            msg_flags);

        ti = proto_tree_add_uint(rt_tree, hf_dec_ctl_msg_hdr, tvb, offset, 1,
            ctl_msg_type);
        ctl_msg_tree = proto_item_add_subtree(ti, ett_dec_rt_ctl_msg);

        /* Get past the msg_flags */
        offset++;
        switch (ctl_msg_type) {
            case RT_CTL_INITIALIZATION:
                    do_initialization_msg(
                        tvb, pinfo, ctl_msg_tree, offset);
            break;
            case RT_CTL_VERIFICATION:
                    do_verification_msg(
                        tvb, pinfo, ctl_msg_tree, offset);
            break;
            case RT_CTL_HELLO_TEST:
                    do_hello_test_msg(
                        tvb, pinfo, ctl_msg_tree, offset);
            break;
            case RT_CTL_LVL1_ROUTING:
            case RT_CTL_LVL2_ROUTING:
                    do_routing_msg(
                        tvb, pinfo, ctl_msg_tree, offset, msg_flags >> 1);
            break;
            case RT_CTL_ETH_ROUTER_HELLO_MSG:
            case RT_CTL_ETH_ENDNODE_HELLO_MSG:
                    do_hello_msg(
                        tvb, pinfo, ctl_msg_tree, offset, msg_flags >> 1);
            break;
            default:
            break;
        }
    } else if (msg_flags & RT_FLAGS_LONG_MSG){
       static int * const msg_bit_flags[] = {
           &hf_dec_rt_long_msg,
           &hf_dec_rt_rqr,
           &hf_dec_rt_rts,
           &hf_dec_rt_inter_eth,
           &hf_dec_rt_discard,
           NULL
        };

        proto_tree_add_bitmask_list_value(flags_tree, tvb, offset, 1, msg_bit_flags, msg_flags);

        /* Increment offset by three:
                1 to get past the flags field
                2 to skip the DEC area/subarea field
         */
        offset += 3;
        ti = proto_tree_add_item(rt_tree, hf_dec_rt_dst_addr, tvb,
                offset, 6, ENC_NA);
        addr = dnet_ntoa(pinfo->pool, (const guint8 *)tvb_memdup(pinfo->pool, tvb, offset, 6));
        if (addr != NULL) {
            proto_item_append_text(ti, " (%s)", addr);
        }

        /* Skip 6 bytes for the MAC and
                2 bytes for DEC area/subarea
            */
        offset += 8;
        ti = proto_tree_add_item(rt_tree, hf_dec_rt_src_addr, tvb,
            offset, 6, ENC_NA);
        addr = dnet_ntoa(pinfo->pool, (const guint8 *)tvb_memdup(pinfo->pool, tvb, offset, 6));
        if (addr != NULL) {
            proto_item_append_text(ti, " (%s)", addr);
        }

        /* Proceed to the NL2 byte */
        offset += 6;
        proto_tree_add_uint(rt_tree, hf_dec_rt_nl2, tvb,
            offset, 1, rt_zero);
        offset++;
        rt_visit_count = tvb_get_guint8(tvb, offset);
        proto_tree_add_uint(rt_tree, hf_dec_rt_visit_count, tvb,
            offset, 1, rt_visit_count);
        offset++;
        proto_tree_add_uint(rt_tree, hf_dec_rt_service_class, tvb,
            offset, 1, rt_zero);
        offset++;
        proto_tree_add_uint(rt_tree, hf_dec_rt_protocol_type, tvb,
            offset, 1, rt_zero);
        offset++;
    } else {
        proto_tree_add_uint(flags_tree, hf_dec_rt_short_msg,
                tvb, offset, 1, msg_flags);
        proto_tree_add_boolean(flags_tree, hf_dec_rt_rqr, tvb,
                    offset, 1, msg_flags);
        proto_tree_add_boolean(flags_tree, hf_dec_rt_rts, tvb,
                    offset, 1, msg_flags);

        /* Increment offset to get past the flags field
         */
        offset++;
        proto_tree_add_item(rt_tree, hf_dec_rt_dst_node, tvb, offset, 2, ENC_LITTLE_ENDIAN);
        offset += 2;
        proto_tree_add_item(rt_tree, hf_dec_rt_src_node, tvb, offset, 2, ENC_LITTLE_ENDIAN);
        offset += 2;
        forward = tvb_get_guint8(tvb, offset);
        proto_tree_add_uint(rt_tree, hf_dec_rt_visited_nodes, tvb,
            offset, 1, forward);
        offset++;
    }

    if (!(msg_flags & RT_FLAGS_CTRL_MSG)) {
        /* It is not a routing control message */
        proto_tree *nsp_msg_tree;
        proto_item *ti_local;
        guint8     nsp_msg_type;

        nsp_msg_type = tvb_get_guint8(tvb, offset);
           ti_local = proto_tree_add_uint(
            tree, hf_dec_nsp_msgs, tvb, offset, 1, nsp_msg_type);
        if (nsp_msg_type == NOP_MSG) {
            /* Only test data in this msg */
            return offset;
        }
        nsp_msg_tree = proto_item_add_subtree(ti_local, ett_dec_rt_nsp_msg);
        /* Get past the nsp_msg_type */
        offset++;
        proto_tree_add_item(nsp_msg_tree, hf_dec_rt_dst_node, tvb, offset, 2, ENC_LITTLE_ENDIAN);
        offset += 2;
        if (nsp_msg_type == CONN_ACK_MSG) {
            col_set_str(pinfo->cinfo, COL_INFO, "NSP connect acknowledgement");
            /* Done with this msg type */
            return offset;
        }
        /* All other messages have a source node */
        proto_tree_add_item(nsp_msg_tree, hf_dec_rt_src_node, tvb, offset, 2, ENC_LITTLE_ENDIAN);
        offset += 2;

        handle_nsp_msg(tvb,
                           pinfo,
                           nsp_msg_tree,
                           offset,
                           nsp_msg_type);
    }
    return tvb_captured_length(tvb);
}

static int
do_initialization_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *tree,
    guint offset)
{
    guint   my_offset = offset;
    guint8  version, eco_nr, user_eco;
    guint8  remainder_count;

    col_set_str(pinfo->cinfo, COL_INFO, "Routing control, initialization message");
    proto_tree_add_item(tree, hf_dec_rt_src_node, tvb,
        my_offset, 2, ENC_LITTLE_ENDIAN);
    my_offset += 2;
    proto_tree_add_item(tree, hf_dec_rt_tiinfo, tvb,
        my_offset, 2, ENC_LITTLE_ENDIAN);
    my_offset += 2;
    proto_tree_add_item(tree, hf_dec_rt_blk_size, tvb,
        my_offset, 2, ENC_LITTLE_ENDIAN);
    my_offset += 2;
    version = tvb_get_guint8(tvb, my_offset);
    eco_nr = tvb_get_guint8(tvb, my_offset + 1);
    user_eco = tvb_get_guint8(tvb, my_offset + 2);
    proto_tree_add_none_format(tree, hf_dec_rt_version, tvb,
        my_offset, 3, "Routing Layer version: %d.%d.%d.",
            version, eco_nr, user_eco);
    my_offset +=3;
    proto_tree_add_item(tree, hf_dec_rt_timer, tvb,
        my_offset, 2, ENC_LITTLE_ENDIAN);
    my_offset += 2;
    remainder_count = tvb_get_guint8(tvb, my_offset);
    if (remainder_count != 0) {
        proto_tree_add_item(tree, hf_dec_rt_reserved, tvb,
            my_offset, remainder_count, ENC_NA);
        my_offset += remainder_count;
    }
    return (my_offset);
}

static int
do_verification_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *tree,
    guint offset)
{
    guint   my_offset = offset;
    guint8  remainder_count;

    col_set_str(pinfo->cinfo, COL_INFO, "Routing control, verification message");
    proto_tree_add_item(tree, hf_dec_rt_src_node, tvb,
        my_offset, 2, ENC_LITTLE_ENDIAN);
    my_offset += 2;
    remainder_count = tvb_get_guint8(tvb, my_offset);
    if (remainder_count != 0) {
        proto_tree_add_item(tree, hf_dec_rt_fcnval, tvb,
            my_offset, remainder_count, ENC_NA);
        my_offset += remainder_count;
    }
    return (my_offset);
}

static int
do_hello_test_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *tree,
    guint offset)
{
    guint   my_offset = offset;
    guint   remainder_count;

    col_set_str(pinfo->cinfo, COL_INFO, "Routing control, hello/test message");
    proto_tree_add_item(tree, hf_dec_rt_src_node, tvb,
        my_offset, 2, ENC_LITTLE_ENDIAN);
    my_offset += 2;
    remainder_count = tvb_reported_length_remaining(tvb, my_offset);
    if (remainder_count != 0) {
        proto_tree_add_item(tree, hf_dec_rt_test_data, tvb,
            my_offset, remainder_count, ENC_NA);
        my_offset += remainder_count;
    }
    return (my_offset);
}

static int
do_routing_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *tree,
    guint offset,
    guint msg)
{
    guint   my_offset = offset;
    guint32 my_checksum = 1;
    guint16 count, startid, rtginfo;
    guint   remainder_count;

    proto_tree_add_item(tree, hf_dec_rt_src_node, tvb,
        my_offset, 2, ENC_LITTLE_ENDIAN);
    /* Skip the 1-byte reserved field */
    my_offset += 3;
    remainder_count = tvb_reported_length_remaining(tvb, my_offset);
    do {
        /* if the remainder_count == 1, only the checksum remains */
        count = tvb_get_letohs(tvb, my_offset);
        startid = tvb_get_letohs(tvb, my_offset + 2);
        rtginfo = tvb_get_letohs(tvb, my_offset + 4);
        if (msg == 3) {
            col_set_str(pinfo->cinfo, COL_INFO, "Routing control, Level 1 routing message");
            proto_tree_add_none_format(tree, hf_dec_rt_segment, tvb,
                my_offset, 6,
                "Segment: count:%d, start Id: %d, hops:%d, cost: %d",
                count, startid, (rtginfo & 0x7c00) >> 10, rtginfo & 0x3ff);
        } else {
            col_set_str(pinfo->cinfo, COL_INFO, "Routing control, Level 2 routing message");
            proto_tree_add_none_format(tree, hf_dec_rt_segment, tvb,
                my_offset, 6,
                "Segment: count:%d, start area: %d, hops:%d, cost: %d",
                count, startid, (rtginfo & 0x7c00) >> 10, rtginfo & 0x3ff);
        };
        my_checksum += (count + startid + rtginfo);
        my_offset += 6;
        remainder_count -= 6;
    } while (remainder_count > 6);
    my_offset += remainder_count - 2;
    /* fold 32 bit sum into 16 bits */
    while (my_checksum>>16)
        my_checksum = (my_checksum & 0xffff) + (my_checksum >> 16);

    proto_tree_add_checksum(tree, tvb, my_offset, hf_dec_rt_checksum, hf_dec_rt_checksum_status, &ei_dec_rt_checksum, pinfo, my_checksum, ENC_LITTLE_ENDIAN, PROTO_CHECKSUM_VERIFY);
    my_offset += 2;
    return (my_offset);
}

static int
do_hello_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *tree,
    guint offset,
    guint msg)
{
    guint   my_offset = offset;
    guint8  priority;
    guint16 version, eco_nr, user_eco;
    proto_item *ti;
    char *addr;
    static int * const info_flags[] = {
        &hf_dec_rt_iinfo_node_type,
        &hf_dec_rt_iinfo_vrf,
        &hf_dec_rt_iinfo_rej,
        &hf_dec_rt_iinfo_verf,
        &hf_dec_rt_iinfo_mta,
        &hf_dec_rt_iinfo_blkreq,
        NULL
    };

    version = tvb_get_guint8(tvb, my_offset);
    eco_nr = tvb_get_guint8(tvb, my_offset + 1);
    user_eco = tvb_get_guint8(tvb, my_offset + 2);
    proto_tree_add_none_format(tree, hf_dec_rt_version, tvb,
        my_offset, 3, "Routing Layer Version: %d.%d.%d",
        version, eco_nr, user_eco);
    my_offset +=3;
    ti = proto_tree_add_item(tree, hf_dec_rt_id, tvb,
        my_offset, 6, ENC_NA);
    addr = dnet_ntoa(pinfo->pool, (const guint8 *)tvb_memdup(pinfo->pool, tvb, my_offset, 6));
    if (addr != NULL) {
        proto_item_append_text(ti, " (%s)", addr);
    }
    my_offset += 6;
    proto_tree_add_bitmask(tree, tvb, my_offset, hf_dec_rt_iinfo, ett_dec_rt_info_flags, info_flags, ENC_NA);
    my_offset++;

    proto_tree_add_item(tree, hf_dec_rt_blk_size, tvb,
        my_offset, 2, ENC_LITTLE_ENDIAN);
    my_offset += 2;
    if (msg == 5) {
        /* Ethernet router hello message
           Has a 'priority' field in this position */
        col_set_str(pinfo->cinfo, COL_INFO, "Routing control, Ethernet Router Hello  message");
        priority = tvb_get_guint8(tvb, my_offset);
        proto_tree_add_uint(
            tree, hf_dec_rt_iprio, tvb, my_offset, 1, priority);
        my_offset++;
    }
    /* Skip the 'area' field common to both hello messages */
    my_offset += 1;
    if (msg == 6) {
        /* The endnode hello message has 'seed' and 'neighbor' fields */
        col_set_str(pinfo->cinfo, COL_INFO, "Routing control, Endnode Hello message");
        proto_tree_add_item(tree, hf_dec_rt_seed, tvb,
                            my_offset, 8, ENC_NA);
        my_offset += 8;
        ti = proto_tree_add_item(tree, hf_dec_rt_neighbor, tvb,
                my_offset, 6, ENC_NA);
        addr = dnet_ntoa(pinfo->pool, (const guint8 *)tvb_memdup(pinfo->pool, tvb, my_offset, 6));
        if (addr != NULL) {
            proto_item_append_text(ti, " (%s)", addr);
        }
        my_offset += 6;
    }
    /*'Timer' and 'mpd' fields are common
      'mpd' field is reserved */
    proto_tree_add_item(tree, hf_dec_rt_timer, tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
    my_offset += 3;
    if (msg == 5) {
        /* The Ethernet router hello message contains
           a list of router states
           The Ethernet Endnode Hello Message contains
           up to 128 bytes of test data at the end.
           These data are left to be dissected as 'data'.
         */
        proto_item  *ti_locala, *ti_ether;
        proto_tree *list_tree, *list_ether;
        guint8 image_len;
        guint8 item_len;

        /* image field is preceded by count of remainder of field */
        image_len = tvb_get_guint8(tvb, my_offset);
        my_offset++;

        ti_locala = proto_tree_add_item(tree, hf_dec_rt_elist, tvb,
            my_offset, image_len, ENC_NA);
        list_tree = proto_item_add_subtree(ti_locala, ett_dec_rt_list);

        while (image_len > 0) {
            ti_ether = proto_tree_add_item(list_tree, hf_dec_rt_ename, tvb,
                my_offset, 7, ENC_NA);
            list_ether = proto_item_add_subtree(ti_ether, ett_dec_rt_rlist);
            my_offset += 7;
            image_len -= 7;

            /* image field is preceded by count of remainder of field */
            item_len = tvb_get_guint8(tvb, my_offset);
            my_offset++;
            image_len -= 1;
            while (item_len > 0)
            {
                guint8  pristate;
                proto_item  *ti_localb;
                proto_tree *pstate_tree;

                ti_localb = proto_tree_add_item(list_ether, hf_dec_rt_router_id,
                    tvb, my_offset, 6, ENC_NA);
                addr = dnet_ntoa(pinfo->pool, (const guint8 *)tvb_memdup(pinfo->pool, tvb, my_offset, 6));
                if (addr != NULL) {
                    proto_item_append_text(ti_localb, " (%s)", addr);
                }
                my_offset += 6;
                pstate_tree = proto_item_add_subtree(ti_localb, ett_dec_rt_state);
                pristate = tvb_get_guint8(tvb, my_offset);
                proto_tree_add_string(pstate_tree, hf_dec_rt_router_state,
                    tvb, my_offset, 1,
                    ((pristate & 0x80) ? "known 2-way": "unknown"));
                proto_tree_add_uint(pstate_tree, hf_dec_rt_router_prio,
                    tvb, my_offset, 1, pristate);
                my_offset++;
                item_len -= 7;
                image_len -= 7;
            }
        }
    }
    return (my_offset);
}

static int
handle_nsp_msg(
    tvbuff_t *tvb,
    packet_info *pinfo,
    proto_tree *tree,
    guint offset,
    guint8 nsp_msg_type)
{
    /* Offset in tvb now points at the first byte still to be handled */
    guint      my_offset = offset;
    gint       data_length;
    guint16    ack_num, ack_dat, ack_oth, seg_num;
    guint8     ls_flags, fc_val, services;
    proto_item  *ti;
    proto_tree *flow_control_tree;

    /* 'tree' is now the subtree for the NSP message */
    switch (nsp_msg_type) {
        case DATA_SEGMENT_MSG:     /* "Data segment" */
        case BOM_MSG:              /* "Beginning of segment message" */
        case EOM_MSG:              /* "End of segment message" */
        case BOM_EOM_MSG:          /* "BOM / EOM message" */
            ack_num = tvb_get_letohs(tvb, my_offset);
            if (ack_num & 0x8000) {
                proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                    tvb, my_offset, 2,
                    "Last data segment %s acknowledged: %d",
                    (ack_num & 0x1000) ? "negatively" : "positively",
                    ack_num & 0xfff);
                my_offset += 2;
                /* There may still be an ackoth field */
                ack_oth = tvb_get_letohs(tvb, my_offset);
                if (ack_oth & 0x8000) {
                    /* There is an ack_oth field */
                    proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                        tvb, my_offset, 2,
                        "Cross sub-channel %s of other data msg %d",
                        ((ack_oth & 0x3000) == 0x2000) ? "ACK" : "NAK",
                        ack_oth & 0xfff);
                    my_offset += 2;
                }
            }
            /*
             * The optional ACKNUM and ACKOTH  fields are not present
             * There is still the segnum field
             */
            seg_num = tvb_get_letohs(tvb, my_offset);
            if (nsp_msg_type == BOM_MSG) {
                dec_dna_total_bytes_this_segment = 0;
                col_append_fstr(pinfo->cinfo, COL_INFO,
                    "msg nr. %d: start of segment",
                    seg_num & 0xfff);
            } else if (nsp_msg_type == DATA_SEGMENT_MSG) {
                col_append_fstr(pinfo->cinfo, COL_INFO,
                    "msg nr. %d: continuation segment ",
                    seg_num & 0xfff);
            } else if (nsp_msg_type == EOM_MSG) {
                col_append_fstr(pinfo->cinfo, COL_INFO,
                    "msg nr. %d: end of segment",
                    seg_num & 0xfff);
            } else if (nsp_msg_type == BOM_EOM_MSG) {
                dec_dna_total_bytes_this_segment = 0;
                col_append_fstr(pinfo->cinfo, COL_INFO,
                    "msg nr. %d single segment",
                    seg_num & 0xfff);
            }
            /* This is the last field, the rest are data */
            proto_tree_add_item(tree, hf_dec_rt_segnum,
                tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
            proto_tree_add_item(tree, hf_dec_rt_delay,
                tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
            my_offset += 2;
            /* Compute the number of bytes in this data segment */
            data_length =
                tvb_reported_length_remaining(tvb, my_offset);
            dec_dna_previous_total = dec_dna_total_bytes_this_segment;
            dec_dna_total_bytes_this_segment += data_length;
            col_append_fstr(pinfo->cinfo, COL_INFO,
                ", bytes this segment: %d, total so far:%d",
                data_length, dec_dna_total_bytes_this_segment);
            /* We are done, return my_offset */
            break;
        case INTERRUPT_MSG:        /* "Interrupt message" */
            col_set_str(pinfo->cinfo, COL_INFO, "NSP interrupt message");
            ack_num = tvb_get_letohs(tvb, my_offset);
            if (ack_num & 0x8000) {
                proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                    tvb, my_offset, 2,
                    "Last interrupt/link service msg %s acknowledged: %d",
                    (ack_num & 0x1000) ? "negatively" : "positively",
                    ack_num & 0xfff);
                my_offset += 2;
                /* There may still be an ack_dat field */
            } else {
                /* There are no ack/nak fields */
                proto_tree_add_item(tree, hf_dec_rt_segnum,
                    tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
                proto_tree_add_item(tree, hf_dec_rt_delay,
                    tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
                my_offset += 2;
                /* We are done, return my_offset */
                break;
            }
            ack_dat = tvb_get_letohs(tvb, my_offset);
            if (ack_dat & 0x8000) {
                /* There is an ack_dat field */
                proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                    tvb, my_offset, 2,
                    "Cross sub-channel %s of data segment msg: %d",
                    ((ack_dat & 0x3000) == 0x2000) ? "ACK" : "NAK",
                   ack_dat & 0xfff);
                my_offset += 2;
            }
            /* This is the last field, the rest are data */
            proto_tree_add_item(tree, hf_dec_rt_segnum,
                tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
            proto_tree_add_item(tree, hf_dec_rt_delay,
                tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
            my_offset += 2;
            /* We are done, return my_offset */
            break;
        case LINK_SERVICE_MSG:     /* "Link service message" */
            col_set_str(pinfo->cinfo, COL_INFO, "NSP link control message");
            ack_num = tvb_get_letohs(tvb, my_offset);
            if (ack_num & 0x8000) {
                proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                    tvb, my_offset, 2,
                    "Last interrupt/link service msg %s acknowledged: %d",
                    (ack_num & 0x1000) ? "negatively" : "positively",
                    ack_num & 0xfff);
                my_offset += 2;
                /* There may still be an ack_dat field */
            } else {
                /* There are no ack/nak fields */
                proto_tree_add_item(tree, hf_dec_rt_segnum,
                    tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
                proto_tree_add_item(tree, hf_dec_rt_delay,
                    tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
                my_offset += 2;
                /* We are done, return my_offset */
                break;
            }
            ack_dat = tvb_get_letohs(tvb, my_offset);
            if (ack_dat & 0x8000) {
                /* There is an ack_dat field */
                proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                    tvb, my_offset, 2,
                    "Cross sub-channel %s of data segment msg: %d",
                    ((ack_dat & 0x3000) == 0x2000) ? "ACK" : "NAK",
                   ack_dat & 0xfff);
                my_offset += 2;
            }
            proto_tree_add_item(tree, hf_dec_rt_segnum,
                tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
            proto_tree_add_item(tree, hf_dec_rt_delay,
                tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
            my_offset += 2;
            /* Now follows the ls_flags field */
            ls_flags = tvb_get_guint8(tvb, my_offset);
            switch(ls_flags) {
                case 0: /* no change */
                    col_append_str(pinfo->cinfo, COL_INFO,
                       "(no change)");
                break;
                case 1: /* stop sending data */
                    col_append_str(pinfo->cinfo, COL_INFO,
                       "(stop)");
                break;
                case 2: /* send data */
                    col_append_str(pinfo->cinfo, COL_INFO,
                       "(go)");
                break;
                default:
                break;
            }
            fc_val = tvb_get_guint8(tvb, my_offset + 1);
            ti = proto_tree_add_uint(tree, hf_dec_flow_control, tvb,
                         my_offset, 1, ls_flags);
            flow_control_tree =
                proto_item_add_subtree(ti, ett_dec_flow_control);
            proto_tree_add_none_format(flow_control_tree, hf_dec_rt_fc_val,
                tvb, my_offset, 2,
                "Request for additional %d %s msgs",
                fc_val, ((ls_flags & 0x04) ? "interrupt" : "data"));
            my_offset += 2;
            break;
        case DATA_ACK_MSG:         /* "Data acknowledgement message" */
            ack_num = tvb_get_letohs(tvb, my_offset);
            proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                tvb, my_offset, 2,
                "Last data segment %s acknowledged: %d",
                (ack_num & 0x1000) ? "negatively" : "positively",
                ack_num & 0xfff);
            my_offset += 2;
            /* There may be an optional ack_oth field */
            col_append_fstr(pinfo->cinfo, COL_INFO,
                "NSP data %s message(%d)",
                    (ack_num & 0x1000) ? "NAK" : "ACK",
                    ack_num & 0xfff);

            if (tvb_reported_length_remaining(tvb, my_offset) > 0) {
                ack_oth = tvb_get_letohs(tvb, my_offset);
                if (ack_oth & 0x8000) {
                    /* There is an ack_oth field */
                    proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                        tvb, my_offset, 2,
                        "Cross sub-channel %s of other data msg %d",
                        ((ack_oth & 0x3000) == 0x2000) ? "ACK" : "NAK",
                        ack_oth & 0xfff);
                    my_offset += 2;
                }
            }
            /* We are done, return my_offset */
            break;
        case OTHER_DATA_ACK_MSG:   /* "Other data acknowledgement message" */
            col_set_str(pinfo->cinfo, COL_INFO, "NSP other data ACK message");
            ack_num = tvb_get_letohs(tvb, my_offset);
            proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                tvb, my_offset, 2,
                "Last interrupt/link service msg %s acknowledged: %d",
                (ack_num & 0x1000) ? "negatively" : "positively",
                ack_num & 0xfff);
            my_offset += 2;
            /* There may be an optional ack_dat field */
            if (tvb_reported_length_remaining(tvb, my_offset) > 0) {
                ack_dat = tvb_get_letohs(tvb, my_offset);
                if (ack_dat & 0x8000) {
                    /* There is an ack_dat field */
                    proto_tree_add_none_format(tree, hf_dec_rt_acknum,
                        tvb, my_offset, 2,
                        "Cross sub-channel %s of data msg %d",
                        ((ack_dat & 0x3000) == 0x2000) ? "ACK" : "NAK",
                        ack_dat & 0xfff);
                    my_offset += 2;
                }
            }
            /* We are done, return my_offset */
            break;
        case CONN_CONFIRM_MSG:     /* "Connect confirm" */
        case CONN_INITIATE_MSG:    /* "Connect initiate" */
            col_set_str(pinfo->cinfo, COL_INFO, "NSP connect confirm/initiate message");
            services = tvb_get_guint8(tvb, my_offset);
            proto_tree_add_uint(tree, hf_dec_rt_services, tvb,
                         my_offset, 1, services);
            my_offset++;
            proto_tree_add_item(tree, hf_dec_rt_info, tvb, my_offset, 1, ENC_LITTLE_ENDIAN);
            my_offset++;
            proto_tree_add_item(tree, hf_dec_rt_seg_size, tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
            my_offset += 2;
            my_offset = handle_connect_contents(tvb, tree, my_offset);
            break;
        case DISCONN_INITIATE_MSG: /* "Disconnect initiate" */
        case DISCONN_CONFIRM_MSG:  /* "Disconnect confirm" */
            col_set_str(pinfo->cinfo, COL_INFO, "NSP disconnect initiate/confirm message");
            proto_tree_add_item(tree, hf_dec_disc_reason, tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
            my_offset += 2;
            if (nsp_msg_type == DISCONN_INITIATE_MSG) {
                my_offset =
                    handle_disc_init_contents( my_offset);
            }
            break;
        default:
            break;
    }
    return (my_offset);
}

static int
handle_connect_contents(
    tvbuff_t *tvb,
    proto_tree *tree,
    guint offset)
{
    guint my_offset = offset;
    proto_item   *ti;
    proto_tree   *contents_tree;
    guint8       dst_format, src_format, obj_type, image_len, menu_ver;

    ti = proto_tree_add_item(tree, hf_dec_conn_contents,
        tvb, my_offset, -1, ENC_NA);
    contents_tree = proto_item_add_subtree(ti, ett_dec_sess_contents);
    /* The destination end user */
    dst_format = tvb_get_guint8(tvb, my_offset);
    my_offset++;
    obj_type = tvb_get_guint8(tvb, my_offset);
    proto_tree_add_uint(contents_tree, hf_dec_sess_obj_type, tvb, my_offset, 1, obj_type);
    my_offset++;
    if (dst_format == 2) {
        proto_tree_add_item(contents_tree, hf_dec_sess_grp_code, tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
        my_offset += 2;
        proto_tree_add_item(contents_tree, hf_dec_sess_usr_code, tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
        my_offset += 2;
    }
    if (dst_format != 0) {
        /* The name field for formats 1 and 2 */
        image_len = tvb_get_guint8(tvb, my_offset);
        my_offset++;
        proto_tree_add_item(contents_tree, hf_dec_sess_dst_name, tvb, my_offset, image_len, ENC_ASCII);
        my_offset += image_len;
    }
    /* The source end user */
    src_format = tvb_get_guint8(tvb, my_offset);
    my_offset++;
    obj_type = tvb_get_guint8(tvb, my_offset);
    proto_tree_add_uint(contents_tree, hf_dec_sess_obj_type,
        tvb, my_offset, 1, obj_type);
    my_offset++;
    if (src_format == 2) {
        proto_tree_add_item(contents_tree, hf_dec_sess_grp_code, tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
        my_offset += 2;
        proto_tree_add_item(contents_tree, hf_dec_sess_usr_code, tvb, my_offset, 2, ENC_LITTLE_ENDIAN);
        my_offset += 2;
    }
    if (dst_format != 0) {
        /* The name field for formats 1 and 2 */
        image_len = tvb_get_guint8(tvb, my_offset);
        my_offset++;
        proto_tree_add_item(contents_tree, hf_dec_sess_src_name,
            tvb, my_offset, image_len, ENC_ASCII);
        my_offset += image_len;
    }
    /* Now the MENUVER field */
    menu_ver = tvb_get_guint8(tvb, my_offset);
    switch (menu_ver) {
        case 1:
        case 3:
            proto_tree_add_string(contents_tree, hf_dec_sess_menu_ver,
                tvb, my_offset, 1,
                "Version 1.0: RQSTRID, PASSWRD and ACCOUNT fields included");
            my_offset++;
            image_len = tvb_get_guint8(tvb, my_offset);
            my_offset++;
            proto_tree_add_item(contents_tree, hf_dec_sess_rqstr_id,
                tvb, my_offset, image_len, ENC_ASCII);
            my_offset += image_len;
            image_len = tvb_get_guint8(tvb, my_offset);
            my_offset++;
            proto_tree_add_item(contents_tree, hf_dec_sess_rqstr_id,
                tvb, my_offset, image_len, ENC_ASCII);
            my_offset += image_len;
            image_len = tvb_get_guint8(tvb, my_offset);
            my_offset++;
            proto_tree_add_item(contents_tree, hf_dec_sess_rqstr_id,
                tvb, my_offset, image_len, ENC_ASCII);
            my_offset += image_len;


            break;
        case 2:
            /* A USRDATA field is handled by dissect_data */
            proto_tree_add_string(contents_tree, hf_dec_sess_menu_ver,
                tvb, my_offset, 1,
                "Version 1.0: USRDATA field included");
            break;
        default:
            proto_tree_add_string(contents_tree, hf_dec_sess_menu_ver,
                tvb, my_offset, 1,
                "Session control version 1.0");
            break;
    }
    return (my_offset);
}

static int
handle_disc_init_contents(
    guint offset)
{
    guint my_offset = offset;

    return (my_offset);
}


void
proto_register_dec_rt(void)
{

    static hf_register_info hf[] = {
        /* Message header items */
        { &hf_dec_routing_flags,
          { "Routing flags",            "dec_dna.flags",
            FT_UINT8,    BASE_HEX,    NULL,    0x0,
            "DNA routing flag", HFILL }},
        { &hf_dec_rt_ctrl_msg,
          { "Control packet",            "dec_dna.flags.control",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    RT_FLAGS_CTRL_MSG,
            NULL, HFILL }},
        { &hf_dec_rt_long_msg,
          { "Long data packet format",     "dec_dna.flags.msglen",
            FT_UINT8,    BASE_HEX,    NULL, 0x06,
            "Long message indicator", HFILL }},
        { &hf_dec_rt_short_msg,
          { "Short data packet format",     "dec_dna.flags.msglen",
            FT_UINT8,    BASE_HEX,    NULL, 0x06,
            "Short message indicator", HFILL }},
        { &hf_dec_rt_rqr,
          { "Return to Sender Request",    "dec_dna.flags.RQR",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    RT_FLAGS_RQR,
            "Return to Sender", HFILL }},
        { &hf_dec_rt_rts,
          { "Packet on return trip",    "dec_dna.flags.RTS",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    RT_FLAGS_RTS,
            NULL, HFILL }},
        { &hf_dec_rt_inter_eth,
          { "Intra-ethernet packet",    "dec_dna.flags.intra_eth",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    RT_FLAGS_INTRA_ETHER,
            NULL, HFILL }},
        { &hf_dec_rt_discard,
          { "Discarded packet",            "dec_dna.flags.discard",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    RT_FLAGS_DISCARD,
            NULL, HFILL }},
        { &hf_dec_rt_dst_addr,
          { "Destination Address",        "dec_dna.dst.address",
            FT_ETHER,    BASE_NONE,    NULL,    0x0,
            NULL, HFILL }},
        { &hf_dec_rt_src_addr,
          { "Source Address",            "dec_dna.src.addr",
            FT_ETHER,    BASE_NONE,    NULL,    0x0,
            NULL, HFILL }},
        { &hf_dec_rt_nl2,
          { "Next level 2 router",        "dec_dna.nl2",
            FT_UINT8,    BASE_HEX,    NULL,   0x0,
            "reserved", HFILL }},
        { &hf_dec_rt_service_class,
          { "Service class",            "dec_dna.svc_cls",
            FT_UINT8,    BASE_HEX,    NULL,   0x0,
            "reserved", HFILL }},
        { &hf_dec_rt_protocol_type,
          { "Protocol type",            "dec_dna.proto_type",
            FT_UINT8,    BASE_HEX,    NULL,   0x0,
            "reserved", HFILL }},
        { &hf_dec_rt_visit_count,
          { "Visit count",            "dec_dna.visit_cnt",
            FT_UINT8,    BASE_HEX,    NULL,   0x0,
            NULL, HFILL }},
        { &hf_dec_flow_control,
          { "Flow control",            "dec_dna.nsp.flow_control",
            FT_UINT8,    BASE_HEX,    VALS(rt_flow_control_vals),   0x3,
            "Flow control(stop, go)", HFILL }},
        { &hf_dec_rt_services,
          { "Requested services",   "dec_dna.nsp.services",
            FT_UINT8,    BASE_HEX,    VALS(rt_services_vals),   0x0c,
            "Services requested", HFILL }},
        { &hf_dec_rt_info,
          { "Version info",            "dec_dna.nsp.info",
            FT_UINT8,    BASE_HEX,    VALS(rt_info_version_vals),   0x03,
            NULL, HFILL }},
        { &hf_dec_rt_dst_node,
          { "Destination node",            "dec_dna.dst_node",
            FT_UINT16,    BASE_HEX,    NULL,   0x0,
            NULL, HFILL }},
        { &hf_dec_rt_seg_size,
          { "Maximum data segment size", "dec_dna.nsp.segsize",
            FT_UINT16,    BASE_DEC,    NULL,   0x0,
            "Max. segment size", HFILL }},
        { &hf_dec_rt_src_node,
          { "Source node",            "dec_dna.src_node",
            FT_UINT16,    BASE_HEX,    NULL,   0x0,
            NULL, HFILL }},
        { &hf_dec_rt_segnum,
          { "Message number",        "dec_dna.nsp.segnum",
            FT_UINT16,    BASE_DEC,    NULL,   0x0fff,
            "Segment number", HFILL }},
        { &hf_dec_rt_delay,
          { "Delayed ACK allowed",  "dec_dna.nsp.delay",
            FT_BOOLEAN,    16,        TFS(&tfs_yes_no),    0x1000,
            "Delayed ACK allowed?", HFILL }},
        { &hf_dec_rt_visited_nodes,
          { "Nodes visited by this package", "dec_dna.vst_node",
            FT_UINT8,    BASE_DEC,    NULL,   0x0,
            "Nodes visited", HFILL }},
        /* Control message items */
        { &hf_dec_ctl_msgs,
          { "Routing control message",        "dec_dna.rt.msg_type",
            FT_UINT8,    BASE_HEX,    VALS(rt_msg_type_vals),    0xe,
            "Routing control", HFILL }},
        { &hf_dec_ctl_msg_hdr,
          { "Routing control message",    "dec_dna.rt.msg_type",
            FT_UINT8,    BASE_HEX,    VALS(rt_msg_type_vals),    0xe,
            "Routing control", HFILL }},
        { &hf_dec_nsp_msgs,
          { "DNA NSP message",        "dec_dna.nsp.msg_type",
            FT_UINT8,    BASE_HEX,    VALS(nsp_msg_type_vals),    0x0,
            "NSP message", HFILL }},
        { &hf_dec_rt_acknum,
          { "Ack/Nak",                "dec_dna.ctl.acknum",
            FT_NONE,    BASE_NONE,    NULL,    0x0,
            "ack/nak number", HFILL }},
        { &hf_dec_rt_fc_val,
          { "Flow control",            "dec_dna.nsp.fc_val",
            FT_NONE,    BASE_NONE,    NULL,    0x0,
            NULL, HFILL }},
        { &hf_dec_rt_tiinfo,
          { "Routing information",    "dec_dna.ctl.tiinfo",
            FT_UINT16,    BASE_HEX,    VALS(rt_tiinfo_vals), 0x0,
            NULL, HFILL }},
        { &hf_dec_rt_blk_size,
          { "Block size",            "dec_dna.ctl.blk_size",
            FT_UINT16,    BASE_DEC,    NULL,    0x0,
            NULL, HFILL }},
        { &hf_dec_disc_reason,
          { "Reason for disconnect","dec_dna.nsp.disc_reason",
            FT_UINT16,    BASE_HEX,    VALS(rt_disc_reason_vals),    0x0,
            "Disconnect reason", HFILL }},
        { &hf_dec_rt_version,
          { "Version",                "dec_dna.ctl.version",
            FT_NONE,    BASE_NONE,    NULL,    0x0,
            "Control protocol version", HFILL }},
        { &hf_dec_rt_timer,
          { "Hello timer(seconds)",  "dec_dna.ctl.timer",
            FT_UINT16,    BASE_DEC,    NULL,   0x0,
            "Hello timer in seconds", HFILL }},
        { &hf_dec_rt_reserved,
          { "Reserved", "dec_dna.ctl.reserved",
            FT_BYTES, BASE_NONE, NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_rt_fcnval,
          { "Verification message function value", "dec_dna.ctl.fcnval",
            FT_BYTES, BASE_NONE, NULL, 0x0,
            "Routing Verification function", HFILL }},
        { &hf_dec_rt_test_data,
          { "Test message data", "dec_dna.ctl.test_data",
            FT_BYTES, BASE_NONE, NULL, 0x0,
            "Routing Test message data", HFILL }},
        { &hf_dec_rt_segment,
          { "Segment",                "dec_dna.ctl.segment",
            FT_NONE,    BASE_NONE,    NULL,    0x0,
            "Routing Segment", HFILL }},
        { &hf_dec_rt_checksum,
          { "Checksum",               "dec_dna.ctl.checksum",
            FT_UINT16,    BASE_HEX,    NULL,    0x0,
            NULL, HFILL }},
        { &hf_dec_rt_checksum_status,
          { "Checksum Status",        "dec_dna.ctl.checksum.status",
            FT_UINT8,     BASE_NONE,   VALS(proto_checksum_vals),    0x0,
            NULL, HFILL }},
        { &hf_dec_rt_id,
          { "Transmitting system ID",            "dec_dna.ctl.id",
            FT_ETHER,    BASE_NONE,    NULL,    0x0,
            NULL, HFILL }},
        { &hf_dec_rt_iinfo,
          { "Routing information",        "dec_dna.ctl.tiinfo",
            FT_UINT8,    BASE_HEX,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_rt_iinfo_node_type,
          { "Node type",            "dec_dna.ctl.iinfo.node_type",
            FT_UINT8,    BASE_HEX,    VALS(rt_iinfo_node_type_vals),    0x03,
            NULL, HFILL }},
        { &hf_dec_rt_iinfo_vrf,
          { "Verification required",            "dec_dna.ctl.iinfo.vrf",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    0x4,
            "Verification required?", HFILL }},
        { &hf_dec_rt_iinfo_rej,
          { "Rejected",            "dec_dna.ctl.iinfo.rej",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    0x8,
            "Rejected message", HFILL }},
        { &hf_dec_rt_iinfo_verf,
          { "Verification failed",            "dec_dna.ctl.iinfo.verf",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    0x10,
            "Verification failed?", HFILL }},
        { &hf_dec_rt_iinfo_mta,
          { "Accepts multicast traffic",            "dec_dna.ctl.iinfo.mta",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    0x20,
            "Accepts multicast traffic?", HFILL }},
        { &hf_dec_rt_iinfo_blkreq,
          { "Blocking requested",            "dec_dna.ctl.iinfo.blkreq",
            FT_BOOLEAN,    8,        TFS(&tfs_yes_no),    0x40,
            "Blocking requested?", HFILL }},
        { &hf_dec_rt_iprio,
          { "Routing priority",        "dec_dna.ctl.prio",
            FT_UINT8,    BASE_HEX,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_rt_neighbor,
          { "Neighbor",                "dec_dna.ctl_neighbor",
            FT_ETHER,    BASE_NONE,    NULL,    0x0,
            "Neighbour ID", HFILL }},
        { &hf_dec_rt_seed,
          { "Verification seed",    "dec_dna.ctl.seed",
            FT_BYTES,    BASE_NONE,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_rt_elist,
          { "List of router states",    "dec_dna.ctl.elist",
            FT_NONE,    BASE_NONE,    NULL, 0x0,
            "Router states", HFILL }},
        { &hf_dec_rt_ename,
          { "Ethernet name",      "dec_dna.ctl.ename",
            FT_BYTES,    BASE_NONE,    NULL,    0x0,
            NULL, HFILL }},
        { &hf_dec_rt_router_id,
          { "Router ID",                "dec_dna.ctl.router_id",
            FT_ETHER,    BASE_NONE,    NULL,    0x0,
            NULL, HFILL }},
        { &hf_dec_rt_router_state,
          { "Router state",    "dec_dna.ctl.router_state",
            FT_STRING,    BASE_NONE,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_conn_contents,
          { "Session connect data",    "dec_dna.sess.conn",
            FT_NONE,    BASE_NONE,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_rt_router_prio,
          { "Router priority",    "dec_dna.ctl.router_prio",
            FT_UINT8,    BASE_HEX,    NULL, 0x7f,
            NULL, HFILL }},
        { &hf_dec_sess_grp_code,
          { "Session Group code",    "dec_dna.sess.grp_code",
            FT_UINT16,    BASE_HEX,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_sess_usr_code,
          { "Session User code",    "dec_dna.sess.usr_code",
            FT_UINT16,    BASE_HEX,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_sess_dst_name,
          { "Session Destination end user",    "dec_dna.sess.dst_name",
            FT_STRING,    BASE_NONE,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_sess_src_name,
          { "Session Source end user",    "dec_dna.sess.src_name",
            FT_STRING,    BASE_NONE,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_sess_obj_type,
          { "Session Object type",    "dec_dna.sess.obj_type",
            FT_UINT8,    BASE_HEX,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_sess_menu_ver,
          { "Session Menu version",    "dec_dna.sess.menu_ver",
            FT_STRING,    BASE_NONE,    NULL, 0x0,
            NULL, HFILL }},
        { &hf_dec_sess_rqstr_id,
          { "Session Requestor ID",    "dec_dna.sess.rqstr_id",
            FT_STRING,    BASE_NONE,    NULL, 0x0,
            NULL, HFILL }},


    };
    static gint *ett[] = {
        &ett_dec_rt,
        &ett_dec_routing_flags,
        &ett_dec_msg_flags,
        &ett_dec_rt_ctl_msg,
        &ett_dec_rt_nsp_msg,
        &ett_dec_rt_info_flags,
        &ett_dec_rt_list,
        &ett_dec_rt_rlist,
        &ett_dec_rt_state,
        &ett_dec_flow_control,
        &ett_dec_sess_contents,
    };

    static ei_register_info ei[] = {
        { &ei_dec_rt_checksum, { "dec_dna.bad_checksum", PI_CHECKSUM, PI_ERROR, "Bad checksum", EXPFILL }},
    };

    expert_module_t* expert_dec_rt;

    proto_dec_rt = proto_register_protocol("DEC DNA Routing Protocol", "DEC_DNA", "dec_dna");
    proto_register_field_array(proto_dec_rt, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
    expert_dec_rt = expert_register_protocol(proto_dec_rt);
    expert_register_field_array(expert_dec_rt, ei, array_length(ei));

    dec_rt_handle = register_dissector("dec_dna", dissect_dec_rt,
                                            proto_dec_rt);
}

void
proto_reg_handoff_dec_rt(void)
{
    dissector_add_uint("ethertype", ETHERTYPE_DNA_RT, dec_rt_handle);
    dissector_add_uint("chdlc.protocol", ETHERTYPE_DNA_RT, dec_rt_handle);
    dissector_add_uint("ppp.protocol", PPP_DEC4, dec_rt_handle);
/*  dissector_add_uint("ppp.protocol", PPP_DECNETCP, dec_rt_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:
 */