summaryrefslogtreecommitdiffstats
path: root/epan/dissectors/packet-opensafety.c
blob: 695fa41b146dcf7be65d81fc5632977857e30373 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
/* packet-opensafety.c
 *
 *   openSAFETY is a machine-safety protocol, encapsulated in modern fieldbus
 *   and industrial ethernet solutions.
 *
 *   For more information see http://www.open-safety.org
 *
 *   This dissector currently supports the following transport protocols
 *
 *   - openSAFETY using POWERLINK
 *   - openSAFETY using SercosIII
 *   - openSAFETY using Generic UDP
 *   - openSAFETY using Modbus/TCP
 *   - openSAFETY using (openSAFETY over UDP) transport
 *   - openSAFETY using ProfiNet IO
 *
 * By Roland Knall <roland.knall@br-automation.com>
 * Copyright 2011-2012 Bernecker + Rainer Industrie-Elektronik Ges.m.b.H.
 *
 * 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/etypes.h>
#include <epan/expert.h>
#include <epan/reassemble.h>
#include <epan/strutil.h>
#include <epan/tap.h>
#include <epan/conversation_table.h>

#include <wsutil/crc8.h>
#include <wsutil/crc16.h>

#include "packet-frame.h"
#include "packet-opensafety.h"

/* General definitions */

/* Used to clasify incoming traffic and presort the heuristic */
#define OPENSAFETY_ANY_TRANSPORT 0x00
#define OPENSAFETY_CYCLIC_DATA   0x01
#define OPENSAFETY_ACYCLIC_DATA  0x02

#ifndef OPENSAFETY_PINFO_CONST_DATA
#define OPENSAFETY_PINFO_CONST_DATA 0xAABBCCDD
#endif

#define OPENSAFETY_REQUEST  TRUE
#define OPENSAFETY_RESPONSE FALSE

/* SPDO Feature Flags
 * Because featureflags are part of the TR field (which is only 6 bit), the field get's shifted */
#define OPENSAFETY_SPDO_FEAT_40BIT_AVAIL   0x20
#define OPENSAFETY_SPDO_FEAT_40BIT_USED    0x10
#define OPENSAFETY_SPDO_FEATURE_FLAGS      (OPENSAFETY_SPDO_FEAT_40BIT_USED | OPENSAFETY_SPDO_FEAT_40BIT_AVAIL)

#define OSS_FRAME_POS_ADDR   0
#define OSS_FRAME_POS_ID     1
#define OSS_FRAME_POS_LEN    2
#define OSS_FRAME_POS_CT     3
#define OSS_FRAME_POS_DATA   4

#define OSS_PAYLOAD_MAXSIZE_FOR_CRC8        0x08
#define OSS_SLIM_FRAME_WITH_CRC8_MAXSIZE    0x13   /* 19 */
#define OSS_SLIM_FRAME2_WITH_CRC8           0x06   /*  6 */
#define OSS_SLIM_FRAME2_WITH_CRC16          0x07   /*  7 */
#define OSS_MINIMUM_LENGTH                  0x0b   /* 11 */
#define OSS_BROADCAST_ADDRESS               0x3ff

#define OPENSAFETY_SPDO_CONNECTION_VALID  0x04

#define OPENSAFETY_SOD_DVI   0x1018
#define OPENSAFETY_SOD_RXMAP 0x1800
#define OPENSAFETY_SOD_TXMAP 0xC000

#define OSS_FRAME_ADDR(f, offset)        (f[OSS_FRAME_POS_ADDR + offset] + ((guint8)((f[OSS_FRAME_POS_ADDR + offset + 1]) << 6) << 2))
#define OSS_FRAME_ID(f, offset)          (f[OSS_FRAME_POS_ID + offset] & 0xFC )
#define OSS_FRAME_LENGTH(f, offset)      (f[OSS_FRAME_POS_LEN + offset])
#define OSS_FRAME_FIELD(f, position)     (f[position])

#define OSS_FRAME_ADDR_T(f, offset)        (tvb_get_guint8(f, OSS_FRAME_POS_ADDR + offset) + ((guint8)((tvb_get_guint8( f, OSS_FRAME_POS_ADDR + offset + 1)) << 6) << 2))
#define OSS_FRAME_ADDR_T2(f, offset, su1, su2)        (( tvb_get_guint8(f, OSS_FRAME_POS_ADDR + offset) ^ su1) + ((guint8)(((tvb_get_guint8( f, OSS_FRAME_POS_ADDR + offset + 1) ^ su2)) << 6) << 2))
#define OSS_FRAME_ID_T(f, offset)          (tvb_get_guint8(f, OSS_FRAME_POS_ID + offset) & 0xFC)
#define OSS_FRAME_LENGTH_T(f, offset)      (tvb_get_guint8(f, OSS_FRAME_POS_LEN + offset))

static int proto_opensafety = -1;

static gint ett_opensafety = -1;
static gint ett_opensafety_checksum = -1;
static gint ett_opensafety_snmt = -1;
static gint ett_opensafety_ssdo = -1;
static gint ett_opensafety_spdo = -1;
static gint ett_opensafety_spdo_flags = -1;
static gint ett_opensafety_ssdo_sacmd = -1;
static gint ett_opensafety_ssdo_payload = -1;
static gint ett_opensafety_ssdo_sodentry = -1;
static gint ett_opensafety_ssdo_extpar = -1;
static gint ett_opensafety_sod_mapping = -1;
static gint ett_opensafety_node = -1;

static expert_field ei_payload_length_not_positive = EI_INIT;
static expert_field ei_payload_unknown_format = EI_INIT;
static expert_field ei_crc_slimssdo_instead_of_spdo = EI_INIT;
static expert_field ei_crc_frame_1_invalid = EI_INIT;
static expert_field ei_crc_frame_1_valid_frame2_invalid = EI_INIT;
static expert_field ei_crc_frame_2_invalid = EI_INIT;
static expert_field ei_crc_frame_2_unknown_scm_udid = EI_INIT;
static expert_field ei_crc_frame_2_scm_udid_encoded = EI_INIT;
static expert_field ei_message_unknown_type = EI_INIT;
static expert_field ei_message_reassembly_size_differs_from_header = EI_INIT;
static expert_field ei_message_spdo_address_invalid = EI_INIT;
static expert_field ei_message_id_field_mismatch = EI_INIT;
static expert_field ei_scmudid_autodetected = EI_INIT;
static expert_field ei_scmudid_invalid_preference = EI_INIT;
static expert_field ei_scmudid_unknown = EI_INIT;
static expert_field ei_40bit_default_domain = EI_INIT;

static int hf_oss_msg = -1;
static int hf_oss_msg_direction = -1;
static int hf_oss_msg_category = -1;
static int hf_oss_msg_node = -1;
static int hf_oss_msg_network = -1;
static int hf_oss_msg_sender = -1;
static int hf_oss_msg_receiver = -1;
static int hf_oss_length= -1;
static int hf_oss_crc = -1;
static int hf_oss_byte_offset = -1;

static int hf_oss_crc_valid = -1;
static int hf_oss_crc2_valid = -1;
static int hf_oss_crc_type  = -1;

static int hf_oss_snmt_slave = -1;
static int hf_oss_snmt_master = -1;
static int hf_oss_snmt_udid = -1;
static int hf_oss_snmt_scm = -1;
static int hf_oss_snmt_tool = -1;
static int hf_oss_snmt_service_id = -1;
static int hf_oss_snmt_error_group = -1;
static int hf_oss_snmt_error_code = -1;
static int hf_oss_snmt_param_type = -1;
static int hf_oss_snmt_ext_addsaddr = -1;
static int hf_oss_snmt_ext_addtxspdo = -1;
static int hf_oss_snmt_ext_initct = -1;

static int hf_oss_ssdo_server = -1;
static int hf_oss_ssdo_client = -1;
static int hf_oss_ssdo_sano = -1;
static int hf_oss_ssdo_sacmd = -1;
static int hf_oss_ssdo_sod_index = -1;
static int hf_oss_ssdo_sod_subindex = -1;
static int hf_oss_ssdo_payload = -1;
static int hf_oss_ssdo_payload_size = -1;
static int hf_oss_ssdo_sodentry_size = -1;
static int hf_oss_ssdo_sodentry_data = -1;
static int hf_oss_ssdo_abort_code = -1;
static int hf_oss_ssdo_preload_queue = -1;
static int hf_oss_ssdo_preload_error = -1;

static int hf_oss_sod_par_timestamp = -1;
static int hf_oss_sod_par_checksum = -1;
static int hf_oss_ssdo_sodmapping = -1;
static int hf_oss_ssdo_sodmapping_bits = -1;

static int hf_oss_ssdo_sacmd_access_type = -1;
static int hf_oss_ssdo_sacmd_preload = -1;
static int hf_oss_ssdo_sacmd_abort_transfer = -1;
static int hf_oss_ssdo_sacmd_segmentation = -1;
static int hf_oss_ssdo_sacmd_toggle = -1;
static int hf_oss_ssdo_sacmd_initiate = -1;
static int hf_oss_ssdo_sacmd_end_segment = -1;
#if 0
static int hf_oss_ssdo_sacmd_reserved = -1;
#endif

static int hf_oss_ssdo_extpar_parset = -1;
static int hf_oss_ssdo_extpar_version = -1;
static int hf_oss_ssdo_extpar_saddr = -1;
static int hf_oss_ssdo_extpar_length = -1;
static int hf_oss_ssdo_extpar_crc = -1;
static int hf_oss_ssdo_extpar_tstamp = -1;
static int hf_oss_ssdo_extpar_data = -1;
static int hf_oss_ssdo_extpar = -1;

static int hf_oss_scm_udid = -1;
static int hf_oss_scm_udid_auto = -1;
static int hf_oss_scm_udid_valid = -1;

static int hf_oss_spdo_direction = -1;
static int hf_oss_spdo_connection_valid = -1;
static int hf_oss_spdo_ct = -1;
static int hf_oss_spdo_ct_40bit = -1;
static int hf_oss_spdo_time_request = -1;
static int hf_oss_spdo_time_request_to = -1;
static int hf_oss_spdo_time_request_from = -1;
static int hf_oss_spdo_feature_flags = -1;
static int hf_oss_spdo_feature_flag_40bit_available = -1;
static int hf_oss_spdo_feature_flag_40bit_used = -1;

static int hf_oss_fragments = -1;
static int hf_oss_fragment = -1;
static int hf_oss_fragment_overlap = -1;
static int hf_oss_fragment_overlap_conflicts = -1;
static int hf_oss_fragment_multiple_tails = -1;
static int hf_oss_fragment_too_long_fragment = -1;
static int hf_oss_fragment_error = -1;
static int hf_oss_fragment_count = -1;
static int hf_oss_reassembled_in = -1;
static int hf_oss_reassembled_length = -1;
static int hf_oss_reassembled_data = -1;

static gint ett_opensafety_ssdo_fragment = -1;
static gint ett_opensafety_ssdo_fragments = -1;

/* Definitions for the openSAFETY ov. UDP transport protocol */
static dissector_handle_t opensafety_udptransport_handle = NULL;

static int proto_oss_udp_transport = -1;

static int hf_oss_udp_transport_version = -1;
static int hf_oss_udp_transport_flags_type = -1;
static int hf_oss_udp_transport_counter = -1;
static int hf_oss_udp_transport_sender = -1;
static int hf_oss_udp_transport_datapoint = -1;
static int hf_oss_udp_transport_length= -1;

static gint ett_oss_udp_transport = -1;

static const true_false_string tfs_udp_transport_cyclic_acyclic = { "Cyclic", "ACyclic" };
static guint global_network_oss_udp_port = OPENSAFETY_UDP_PORT;

static int opensafety_tap = -1;

static const fragment_items oss_frag_items = {
    /* Fragment subtrees */
    &ett_opensafety_ssdo_fragment,
    &ett_opensafety_ssdo_fragments,
    /* Fragment fields */
    &hf_oss_fragments,
    &hf_oss_fragment,
    &hf_oss_fragment_overlap,
    &hf_oss_fragment_overlap_conflicts,
    &hf_oss_fragment_multiple_tails,
    &hf_oss_fragment_too_long_fragment,
    &hf_oss_fragment_error,
    &hf_oss_fragment_count,
    /* Reassembled in field */
    &hf_oss_reassembled_in,
    /* Reassembled length field */
    &hf_oss_reassembled_length,
    /* Reassembled data */
    &hf_oss_reassembled_data,
    /* Tag */
    "Message fragments"
};

static const char *global_scm_udid = "00:00:00:00:00:00";

static dissector_handle_t data_dissector = NULL;
static dissector_handle_t opensafety_udpdata_handle = NULL;
static dissector_handle_t opensafety_mbtcp_handle = NULL;
static dissector_handle_t opensafety_pnio_handle = NULL;

static gboolean global_display_intergap_data   = FALSE;
static gboolean global_scm_udid_autoset        = TRUE;
static gboolean global_udp_frame2_first        = FALSE;
static gboolean global_siii_udp_frame2_first   = FALSE;
static gboolean global_mbtcp_big_endian        = FALSE;
static guint global_network_udp_port           = OPENSAFETY_UDP_PORT;
static guint global_network_udp_port_sercosiii = OPENSAFETY_UDP_PORT_SIII;
static gboolean global_classify_transport      = TRUE;

static gboolean global_enable_udp    = TRUE;
static gboolean global_enable_mbtcp  = TRUE;

static gboolean global_opensafety_debug_verbose = FALSE;

static const char * global_filter_nodes = "";
static gboolean global_show_only_node_in_filter = TRUE;
static wmem_list_t * global_filter_list = NULL;

static gboolean heuristic_siii_dissection_enabled = TRUE;

static heur_dissector_list_t heur_opensafety_spdo_subdissector_list;

static gboolean bDissector_Called_Once_Before = FALSE;
/* Using local_scm_udid as read variable for global_scm_udid, to
 * enable automatic detection of scm udid */
static char *local_scm_udid = NULL;

static reassembly_table os_reassembly_table;

/* Resets the dissector in case the dissection is malformed and the dissector crashes */
static void
reset_dissector(void)
{
    bDissector_Called_Once_Before = FALSE;
}

static void
setup_dissector(void)
{
    heur_dtbl_entry_t * heur_entry = NULL;

    /* create list if it does not exist, but clean existing elements anyway,
     * as options might have changed */
    global_filter_list = wmem_list_new(wmem_file_scope());

    gchar ** vector = wmem_strsplit(wmem_file_scope(), global_filter_nodes, ",", -1);
    for (; NULL != *vector; vector++ )
    {
        if ( *vector && g_ascii_strtoll(*vector, NULL, 10) > 0 )
            wmem_list_append(global_filter_list, GINT_TO_POINTER(g_ascii_strtoll(*vector, NULL, 10)));
    }

    heur_entry = find_heur_dissector_by_unique_short_name("opensafety_sercosiii");
    if ( heur_entry != NULL )
        heuristic_siii_dissection_enabled = heur_entry->enabled;
}

static void
cleanup_dissector(void)
{
    local_scm_udid = NULL;

    if ( global_filter_list )
    {
        wmem_destroy_list(global_filter_list);
        global_filter_list = NULL;
    }
}

void proto_register_opensafety(void);
void proto_reg_handoff_opensafety(void);

/* Conversation functions */

/* This is defined by the specification. The Address field is 10 bits long, and the node with the number
 *  1 is always the SCM, therefore ( 2 ^ 10 ) - 1 nodes can be addressed. We use 2 ^ 10 here, because the
 *  SCM can talk to himself (Assign SADR for instance ) */
/* #define MAX_NUMBER_OF_SAFETY_NODES      ( 1 << 10 ) */

/* Tracks the information that the packet pinfo has been received by receiver, and adds that information to the tree, using pos, as
 * byte position in the PDU */
static void
opensafety_packet_node(tvbuff_t * message_tvb, packet_info *pinfo, proto_tree *tree,
        gint hf_field, guint16 saddr, guint16 posInFrame, guint16 posSdnInFrame, guint16 sdn )
{
    proto_item *psf_item = NULL;
    proto_tree *psf_tree  = NULL;

    psf_item = proto_tree_add_uint(tree, hf_field, message_tvb, posInFrame, 2, saddr);
    psf_tree = proto_item_add_subtree(psf_item, ett_opensafety_node);
    psf_item = proto_tree_add_uint(psf_tree, hf_oss_msg_node, message_tvb, posInFrame, 2, saddr);
    proto_item_set_generated(psf_item);

    if ( sdn > 0 )
    {
        psf_item = proto_tree_add_uint(psf_tree, hf_oss_msg_network, message_tvb,
                posSdnInFrame, 2, sdn);
    } else if ( sdn <= 0 ) {
        psf_item = proto_tree_add_uint(psf_tree, hf_oss_msg_network, message_tvb,
                posSdnInFrame, 2, sdn * -1);
        expert_add_info(pinfo, psf_item, &ei_scmudid_unknown );
    }
    proto_item_set_generated(psf_item);
}

static void
opensafety_packet_receiver(tvbuff_t * message_tvb, packet_info *pinfo, proto_tree *tree, proto_item *opensafety_item,
        opensafety_packet_info *packet, guint16 recv,
        guint16 posInFrame, guint16 posSdnInFrame, guint16 sdn )
{
    packet->receiver = recv;
    if ( sdn > 0 )
        packet->sdn = sdn;

    opensafety_packet_node (message_tvb, pinfo, tree, hf_oss_msg_receiver, recv, posInFrame, posSdnInFrame, sdn );
    proto_item_append_text(opensafety_item, ", Dst: 0x%03X (%d)", recv, recv);
}

/* Tracks the information that the packet pinfo has been sent by sender, and received by everyone else, and adds that information to
 * the tree, using pos, as byte position in the PDU */
static void
opensafety_packet_sender(tvbuff_t * message_tvb, packet_info *pinfo, proto_tree *tree, proto_item *opensafety_item,
        opensafety_packet_info *packet, guint16 sender,
        guint16 posInFrame, guint16 posSdnInFrame, guint16 sdn )
{
    packet->sender = sender;
    if ( sdn > 0 )
        packet->sdn = sdn;

    opensafety_packet_node (message_tvb, pinfo, tree, hf_oss_msg_sender, sender, posInFrame, posSdnInFrame, sdn );
    proto_item_append_text(opensafety_item, ", Src: 0x%03X (%d)", sender, sender);
}

/* Tracks the information that the packet pinfo has been sent by sender, and received by receiver, and adds that information to
 * the tree, using pos for the sender and pos2 for the receiver, as byte position in the PDU */
static void
opensafety_packet_sendreceiv(tvbuff_t * message_tvb, packet_info *pinfo, proto_tree *tree, proto_item *opensafety_item,
        opensafety_packet_info *packet, guint16 send, guint16 pos,
        guint16 recv, guint16 pos2, guint16 posnet, guint16 sdn)
{
        opensafety_packet_receiver(message_tvb, pinfo, tree, opensafety_item, packet, recv, pos2, posnet, sdn);
        opensafety_packet_sender(message_tvb, pinfo, tree, opensafety_item, packet, send, pos, posnet, sdn);
}

static proto_item *
opensafety_packet_response(tvbuff_t *message_tvb, proto_tree *sub_tree, opensafety_packet_info *packet, gboolean isResponse)
{
    proto_item *item = NULL;
    guint8 b_id = 0;

    if ( packet->msg_type != OPENSAFETY_SPDO_MESSAGE_TYPE )
    {
        proto_tree_add_item(sub_tree, hf_oss_msg, message_tvb,
            OSS_FRAME_POS_ID + packet->frame.subframe1, 1, ENC_NA );
    }
    else
    {
        /* SPDOs code the connection valid bit on offset 0x04. SSDO and SNMT frames use this
         * bit for messages. Therefore setting a bitmask on the hf-field would not work. */
        b_id = OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1) & 0xF8;
        proto_tree_add_uint(sub_tree, hf_oss_msg, message_tvb, OSS_FRAME_POS_ID + packet->frame.subframe1, 1, b_id);
    }

    item = proto_tree_add_item(sub_tree, packet->msg_type != OPENSAFETY_SPDO_MESSAGE_TYPE ? hf_oss_msg_direction : hf_oss_spdo_direction,
            message_tvb, OSS_FRAME_POS_ID + packet->frame.subframe1, 1, ENC_NA);
    if ( ! isResponse )
        packet->is_request = TRUE;

    return item;
}

static proto_tree *
opensafety_packet_payloadtree(packet_info *pinfo, tvbuff_t *message_tvb, proto_tree *opensafety_tree,
        opensafety_packet_info *packet, gint ett_tree)
{
    proto_item *item = NULL;

    item = proto_tree_add_item(opensafety_tree, hf_oss_msg_category, message_tvb, OSS_FRAME_POS_ID + packet->frame.subframe1, 1, ENC_NA );
    proto_item_set_generated(item);

    if ( packet->msg_type == OPENSAFETY_SNMT_MESSAGE_TYPE)
        packet->payload.snmt = wmem_new0(pinfo->pool, opensafety_packet_snmt);
    else if ( packet->msg_type == OPENSAFETY_SSDO_MESSAGE_TYPE || packet->msg_type == OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE )
    {
        packet->payload.ssdo = wmem_new0(pinfo->pool, opensafety_packet_ssdo);
        if ( packet->msg_type == OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE )
            packet->payload.ssdo->is_slim = TRUE;
    }
    else if ( packet->msg_type == OPENSAFETY_SPDO_MESSAGE_TYPE )
        packet->payload.spdo = wmem_new0(pinfo->pool, opensafety_packet_spdo);

    return proto_item_add_subtree(item, ett_tree);
}

static guint16
findFrame1Position ( packet_info *pinfo, tvbuff_t *message_tvb, guint16 byte_offset, guint8 dataLength, gboolean checkIfSlimMistake )
{
    guint16  i_wFrame1Position                   = 0;
    guint16  i_payloadLength, i_calculatedLength = 0;
    guint16  i_offset                            = 0, calcCRC = 0, frameCRC = 0;
    guint8   b_tempByte                          = 0;
    guint8  *bytes = NULL;

    /*
     * First, a normal package is assumed. Calculation of frame 1 position is
     * pretty easy, because, the length of the whole package is 11 + 2*n + 2*o, which
     * results in frame 1 start at (6 + n + o), which is length / 2 + 1
     */
    i_wFrame1Position = dataLength / 2 + 1;
    i_payloadLength = tvb_get_guint8(message_tvb, byte_offset + i_wFrame1Position + 2 );
    /* Calculating the assumed frame length, taking CRC8/CRC16 into account */
    i_calculatedLength = i_payloadLength * 2 + 11 + 2 * (i_payloadLength > OSS_PAYLOAD_MAXSIZE_FOR_CRC8 ? 1 : 0);

    /* To prevent miscalculations, where by chance the byte at [length / 2] + 3 is a value matching a possible payload length,
     * but in reality the frame is a slim ssdo, the CRC of frame 1 gets checked additionally. This check
     * is somewhat time consuming, so it will only run if the normal check led to a mistake detected along the line */
    if ( checkIfSlimMistake && i_calculatedLength == dataLength )
    {
        if (dataLength > OSS_PAYLOAD_MAXSIZE_FOR_CRC8)
            frameCRC = tvb_get_letohs(message_tvb,  byte_offset + i_wFrame1Position + dataLength + OSS_FRAME_POS_DATA);
        else
            frameCRC = tvb_get_guint8(message_tvb,  byte_offset + i_wFrame1Position + dataLength + OSS_FRAME_POS_DATA);

        bytes = (guint8*)tvb_memdup(pinfo->pool, message_tvb, byte_offset + i_wFrame1Position, dataLength + 4);
        if ( dataLength > OSS_PAYLOAD_MAXSIZE_FOR_CRC8 )
        {
            calcCRC = crc16_0x755B(bytes, dataLength + 4, 0);
            if ( frameCRC != calcCRC )
                calcCRC = crc16_0x5935(bytes, dataLength + 4, 0);
        }
        else
            calcCRC = crc8_0x2F(bytes, dataLength + 4, 0);

        /* if the calculated crc does not match the detected, the package is not a normal openSAFETY package */
        if ( frameCRC != calcCRC )
            dataLength = 0;
    }

    /* If the calculated length differs from the given length, a slim package is assumed. */
    if ( i_calculatedLength != dataLength )
    {
        /* possible slim package */
        i_wFrame1Position = 0;
        /*
         * Slim packages have a fixed sublength of either 6 bytes for frame 2 in
         * case of crc8 and 7 bytes in case of crc16
         */
        i_offset = OSS_SLIM_FRAME2_WITH_CRC8 + ( dataLength < (OSS_SLIM_FRAME_WITH_CRC8_MAXSIZE + 1) ? 0 : 1 );
        /* Last 2 digits belong to addr, therefore have to be cleared */
        b_tempByte = ( tvb_get_guint8 ( message_tvb, byte_offset + i_offset + 1 ) ) & 0xFC;

        /* If the id byte xor 0xE8 is 0, we have a slim package */
        if ( ( ( b_tempByte ^ OPENSAFETY_MSG_SSDO_SLIM_SERVICE_REQUEST ) == 0 ) ||
             ( ( b_tempByte ^ OPENSAFETY_MSG_SSDO_SLIM_SERVICE_RESPONSE ) == 0 ) )
        {
            /* Slim package found */
            i_wFrame1Position = i_offset;
        }
    }

    return i_wFrame1Position;
}

static gboolean findSafetyFrame ( packet_info *pinfo, tvbuff_t *message_tvb, guint u_Offset, gboolean b_frame2first,
        guint *u_frameOffset, guint *u_frameLength, opensafety_packet_info *packet )
{
    guint     ctr, rem_length;
    guint16   crc, f2crc, calcCrc = 0;
    guint8    b_Length = 0, b_CTl = 0, crcOffset = 0, crc1Type = 0;
    guint8   *bytes;
    guint     b_ID = 0;
    gboolean  found;

    found = FALSE;
    ctr = u_Offset;
    rem_length = tvb_reported_length_remaining (message_tvb, ctr);

    /* Search will allways start at the second byte of the frame ( cause it determines )
     * the type of package and therefore everything else. Therefore the mininmum length - 1
     * is the correct minimum length */
    while ( rem_length >= ( OSS_MINIMUM_LENGTH - 1 ) )
    {
        /* The ID byte must ALWAYS be the second byte, therefore 0 is invalid,
         * also, the byte we want to access, must at least exist, otherwise,
         * the frame is not detectable as an openSAFETY frame.
         * We check for ID and length */
        if ( ctr != 0 && tvb_bytes_exist(message_tvb, ctr, 2) )
        {
            *u_frameLength = 0;
            *u_frameOffset = 0;

            crcOffset = 0;
            b_ID = tvb_get_guint8(message_tvb, ctr );

            if ( b_ID != 0x0 )
            {
                b_Length = tvb_get_guint8(message_tvb, ctr + 1 );

                /* 0xFF is often used, but always false, otherwise start detection, if the highest
                 *  bit is set */
                if ( ( b_ID != 0xFF ) && ( b_ID & 0x80 ) )
                {
                    /* The rem_length value might be poluted, due to the else statement of
                     * above if-decision (frame at end position detection). Therefore we
                     * calculate it here again, to have a sane value */
                    rem_length = tvb_reported_length_remaining(message_tvb, ctr);

                    /* Plausability check on length */
                    if ( (guint)( b_Length * 2 ) < ( rem_length + OSS_MINIMUM_LENGTH ) )
                    {

                        /* The calculated length must fit, but for the CRC16 check, also the calculated length
                         * plus the CRC16 end position must fit in the remaining length */
                        if ( ( b_Length <= (guint) 8 && ( b_Length <= rem_length ) ) ||
                            ( b_Length > (guint) 8 && ( ( b_Length + (guint) 5 ) <= rem_length ) ) )
                        {
                            /* Ensure, that the correct length for CRC calculation
                             * still exists in byte stream, so that we can calculate the crc */
                            if ( tvb_bytes_exist(message_tvb, ctr - 1, b_Length + 5) )
                            {
                                /* An openSAFETY command has to have a high-byte range between 0x0A and 0x0E
                                 *  b_ID & 0x80 took care of everything underneath, we check for 0x09 and 0x0F,
                                 *  as they remain the only values left, which are not valid */
                                if ( ( ( b_ID >> 4 ) != 0x09 ) && ( ( b_ID >> 4 ) != 0x0F ) )
                                {
                                    /* Read CRC from position */
                                    crc = tvb_get_guint8(message_tvb, ctr + 3 + b_Length );

                                    /* There exists some false positives, where the only possible
                                     * data information in the frame is the ID and the ADDR fields.
                                     * The rest of the fields in frame 1 are zeroed out. The packet
                                     * must be filtered out and may not be used. To detect it, we
                                     * check for the CT value, which, if zero indicates strongly
                                     * that this is false-positive. */
                                    b_CTl = tvb_get_guint8(message_tvb, ctr + 2 );

                                    /* If either length, crc or CTl is not zero, this may be a
                                     * correct package. If all three are 0, this is most certainly
                                     * an incorrect package, because the possibility of a valid
                                     * package with all three values being zero is next to impossible */
                                    if ( b_Length != 0x00 || crc != 0x00 || b_CTl != 0x00 )
                                    {
                                        /* calculate checksum */
                                        bytes = (guint8 *)tvb_memdup(pinfo->pool, message_tvb, ctr - 1, b_Length + 5 );
                                        if ( b_Length > 8 )
                                        {
                                            crc = tvb_get_letohs ( message_tvb, ctr + 3 + b_Length );
                                            crcOffset = 1;

                                            crc1Type = OPENSAFETY_CHECKSUM_CRC16;
                                            calcCrc = crc16_0x755B( bytes, b_Length + 4, 0 );
                                            if ( ( crc ^ calcCrc ) != 0 )
                                            {
                                                calcCrc = crc16_0x5935( bytes, b_Length + 4, 0 );
                                                if ( ( crc ^ calcCrc ) == 0 )
                                                    crc1Type = OPENSAFETY_CHECKSUM_CRC16SLIM;
                                                else
                                                    crc1Type = OPENSAFETY_CHECKSUM_INVALID;
                                            }
                                        } else {
                                            crc1Type = OPENSAFETY_CHECKSUM_CRC8;
                                            calcCrc = crc8_0x2F ( bytes, b_Length + 4, 0 );
                                        }

                                        if ( ( crc ^ calcCrc ) == 0 )
                                        {
                                            /* Check if this is a Slim SSDO message */
                                            if ( ( b_ID >> 3 ) == ( OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE >> 3 ) )
                                            {
                                                /* Slim SSDO messages must have a length != 0, as the first byte
                                                 * in the payload contains the SOD access command */
                                                if ( b_Length > 0 )
                                                {
                                                    *u_frameOffset = ( ctr - 1 );
                                                    *u_frameLength = b_Length + 2 * crcOffset + 11;

                                                    /* It is highly unlikely, that both frame 1 and frame 2 generate
                                                     * a crc == 0 or equal crc's. Therefore we check, if both crc's are
                                                     * equal. If so, it is a falsely detected frame. */
                                                    f2crc = tvb_get_guint8 ( message_tvb, ctr + 3 + 5 + b_Length );
                                                    if ( b_Length > 8 )
                                                        f2crc = tvb_get_letohs ( message_tvb, ctr + 3 + 5 + b_Length );
                                                    if ( crc != f2crc )
                                                    {
                                                        found = TRUE;
                                                        break;
                                                    }
                                                }
                                            }
                                            else
                                            {
                                                *u_frameLength = 2 * b_Length + 2 * crcOffset + 11;
                                                *u_frameOffset = ( ctr - 1 );

                                                /* If the first crc is zero, the second one must not be 0. The header
                                                 * for each subfields differ, therefore it is impossible, that both
                                                 * crcs are zero */
                                                if ( crc == 0 )
                                                {
                                                    f2crc = tvb_get_guint8 ( message_tvb, ( ctr - 1 ) + 10 + ( 2 * b_Length ) );
                                                    if ( b_Length > 8 )
                                                        f2crc = tvb_get_letohs ( message_tvb, ( ctr - 1 ) + 11 + ( 2 * b_Length ) );

                                                    /* The crc's differ, everything is ok */
                                                    if ( crc != f2crc )
                                                    {
                                                        found = TRUE;
                                                        break;
                                                    }
                                                }
                                                else
                                                {
                                                    /* At this point frames had been checked for SoC and SoA types of
                                                     * EPL. This is no longer necessary and leads to false-negatives.
                                                     * SoC and SoA frames get filtered out at the EPL entry point, cause
                                                     * EPL only provides payload, no longer complete frames. */
                                                    found = TRUE;
                                                    break;
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
                else
                {
                    /* There exist frames, where the last openSAFETY frame is sitting in the
                     * very last bytes of the frame, and the complete frame itself contains
                     * more than one openSAFETY frame. It so happens that in such a case, the
                     * last openSAFETY frame will miss detection.
                     *
                     * If so we look at the transported length, calculate the frame length,
                     * and take a look if the calculated frame length, might be a fit for the
                     * remaining length. If such is the case, we increment ctr and increment
                     * rem_length (to hit the while loop one more time) and the frame will be
                     * detected correctly. */
                    if ( rem_length == OSS_MINIMUM_LENGTH )
                    {
                        b_ID = tvb_get_guint8(message_tvb, ctr );
                        b_Length = tvb_get_guint8(message_tvb, ctr + 2 );
                        if ( ( b_ID >> 3 ) == ( OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE >> 3 ) )
                            b_Length = ( 11 + ( b_Length > 8 ? 2 : 0 ) + b_Length );
                        else
                            b_Length = ( 11 + ( b_Length > 8 ? 2 : 0 ) + 2 * b_Length );

                        if ( rem_length == b_Length )
                        {
                            ctr++;
                            rem_length++;
                            continue;
                        }
                    }
                }
            }
        }

        ctr++;
        rem_length = tvb_reported_length_remaining(message_tvb, ctr);

    }

    /* Store packet information in packet_info */
    if ( found && packet )
    {
        packet->msg_id = b_ID;
        packet->msg_len = b_Length;
        packet->frame_len = *u_frameLength;

        /* Should be the calculated crc, which is the same as the frame crc */
        packet->crc.frame1 = calcCrc;
        packet->crc.type = crc1Type;
        if ( packet->crc.type != OPENSAFETY_CHECKSUM_INVALID )
            packet->crc.valid1 = TRUE;
        else
            packet->crc.valid1 = FALSE;
    }

    /* Seem redundant if b_frame2First is false. But in this case, the function is needed for the
     * simple detection of a possible openSAFETY frame.  */
    if ( b_frame2first && found )
        *u_frameOffset = u_Offset;

    return found;
}

static gint
dissect_data_payload ( proto_tree *epl_tree, tvbuff_t *tvb, packet_info *pinfo, gint offset, gint len, guint8 msgType )
{
        gint off = 0;
        tvbuff_t * payload_tvb = NULL;
        heur_dtbl_entry_t *hdtbl_entry = NULL;

        off = offset;

        if (len > 0)
        {
                payload_tvb = tvb_new_subset_length_caplen(tvb, off, len, tvb_reported_length_remaining(tvb, offset) );
                if ( ! dissector_try_heuristic(heur_opensafety_spdo_subdissector_list, payload_tvb, pinfo, epl_tree, &hdtbl_entry, &msgType))
                        call_dissector(data_dissector, payload_tvb, pinfo, epl_tree);

                off += len;
        }

        return off;
}

static void
dissect_opensafety_spdo_message(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *opensafety_tree,
        opensafety_packet_info * packet, proto_item * opensafety_item )
{
    proto_item *item, *diritem;
    proto_tree *spdo_tree, *spdo_flags_tree;
    guint16     ct, addr;
    guint64     ct40bit;
    gint16      taddr, sdn;
    guint       dataLength;
    guint8      tr, b_ID, spdoFlags;

    dataLength = tvb_get_guint8(message_tvb, OSS_FRAME_POS_LEN + packet->frame.subframe1);
    b_ID = tvb_get_guint8(message_tvb, packet->frame.subframe1 + 1) & 0xF8;

    /* Network address is xor'ed into the start of the second frame, but only legible, if the scm given is valid */
    sdn = ( ( OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1) ) ^
            ( OSS_FRAME_ADDR_T2(message_tvb, packet->frame.subframe2, packet->scm_udid[0], packet->scm_udid[1]) ) );
    if ( ! packet->scm_udid_valid )
        sdn = ( -1 * sdn );

    /* taddr is the 4th octet in the second frame */
    tr = ( tvb_get_guint8(message_tvb, packet->frame.subframe2 + 4)  ^ packet->scm_udid[4] ) & 0xFC;

    /* allow only valid SPDO flags */
    spdoFlags = ( ( tr >> 2 ) & OPENSAFETY_SPDO_FEATURE_FLAGS );

    /* An SPDO is always sent by the producer, to everybody else .
     * For a 40bit connection OPENSAFETY_DEFAULT_DOMAIN is assumed as sdn value for now */
    if ( (OPENSAFETY_SPDO_FEAT_40BIT_USED & spdoFlags ) == OPENSAFETY_SPDO_FEAT_40BIT_USED )
        sdn = OPENSAFETY_DEFAULT_DOMAIN;

    /* Determine the producer and set it, as opensafety_packet_node does not */
    addr = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1);
    packet->sender = addr;

    opensafety_packet_node ( message_tvb, pinfo, opensafety_tree, hf_oss_msg_sender,
            addr, OSS_FRAME_POS_ADDR + packet->frame.subframe1, packet->frame.subframe2, sdn );
    proto_item_append_text(opensafety_item, "; Producer: 0x%03X (%d)", addr, addr);

    spdo_tree = opensafety_packet_payloadtree ( pinfo, message_tvb, opensafety_tree, packet, ett_opensafety_spdo );

    /* Determine SPDO Flags. Attention packet->payload.spdo exists ONLY AFTER opensafety_packet_payloadtree */
    packet->payload.spdo->flags.enabled40bit = FALSE;
    packet->payload.spdo->flags.requested40bit = FALSE;

    if ( (OPENSAFETY_SPDO_FEAT_40BIT_AVAIL & spdoFlags ) == OPENSAFETY_SPDO_FEAT_40BIT_AVAIL )
        packet->payload.spdo->flags.requested40bit = TRUE;
    if ( packet->payload.spdo->flags.requested40bit && ( (OPENSAFETY_SPDO_FEAT_40BIT_USED & spdoFlags ) == OPENSAFETY_SPDO_FEAT_40BIT_USED ) )
        packet->payload.spdo->flags.enabled40bit = TRUE;

    diritem = opensafety_packet_response(message_tvb, spdo_tree, packet, b_ID == OPENSAFETY_MSG_SPDO_DATA_WITH_TIME_RESPONSE );
    proto_tree_add_item(spdo_tree, hf_oss_spdo_connection_valid, message_tvb, OSS_FRAME_POS_ID + packet->frame.subframe1, 1, ENC_NA);

    packet->payload.spdo->conn_valid = (tvb_get_guint8(message_tvb, OSS_FRAME_POS_ID + packet->frame.subframe1) & 0x04) == 0x04;

    /* taddr is the 4th octet in the second frame */
    taddr = OSS_FRAME_ADDR_T2(message_tvb, packet->frame.subframe2 + 3, packet->scm_udid[3], packet->scm_udid[4]);
    tr = ( tvb_get_guint8(message_tvb, packet->frame.subframe2 + 4)  ^ packet->scm_udid[4] ) & 0xFC;

    /* determine the ct value. if complete it can be used for analysis of the package */
    ct = tvb_get_guint8(message_tvb, packet->frame.subframe1 + 3);
    if ( packet->scm_udid_valid )
    {
        ct = (guint16)((tvb_get_guint8(message_tvb, packet->frame.subframe2 + 2) ^ packet->scm_udid[2]) << 8) +
            (tvb_get_guint8(message_tvb, packet->frame.subframe1 + 3));
    }

    if ( b_ID == OPENSAFETY_MSG_SPDO_DATA_WITH_TIME_REQUEST )
    {
        proto_item_append_text(diritem, " (Safety Node: %03d)", taddr);
        item = proto_tree_add_uint_format_value(spdo_tree, hf_oss_spdo_ct, message_tvb, 0, 0, ct,
                                                "0x%04X [%d] (%s)", ct, ct,
                                                (packet->scm_udid_valid ? "Complete" : "Low byte only"));
        proto_item_set_generated(item);
        packet->payload.spdo->counter.b16 = ct;

        packet->payload.spdo->timerequest = taddr;
        proto_tree_add_uint(spdo_tree, hf_oss_spdo_time_request, message_tvb,
                            OSS_FRAME_POS_ADDR + packet->frame.subframe2 + 4, 1, tr);
        opensafety_packet_node ( message_tvb, pinfo, spdo_tree, hf_oss_spdo_time_request_from, taddr,
                OSS_FRAME_POS_ADDR + packet->frame.subframe2 + 3, packet->frame.subframe2, sdn );
    }
    else
    {
        if ( ! (b_ID == OPENSAFETY_MSG_SPDO_DATA_ONLY) || !(packet->payload.spdo->flags.enabled40bit) )
        {
            item = proto_tree_add_uint_format_value(spdo_tree, hf_oss_spdo_ct, message_tvb, 0, 0, ct,
                    "0x%04X [%d] (%s)", ct, ct, (packet->scm_udid_valid ? "Complete" : "Low byte only"));
            proto_item_set_generated(item);
            packet->payload.spdo->counter.b16 = ct;
        }
        else
        {
            /* 40bit counter is calculated from various fields. Therefore it cannot be read
             * directly from the frame. All fields starting after or with packet->frame.subframe2 have to
             * be decoded using the scm udid */
            ct40bit = (tvb_get_guint8(message_tvb, packet->frame.subframe2 + 3) ^ packet->scm_udid[3]);
            ct40bit <<= 8;
            ct40bit += ((guint64)(tvb_get_guint8(message_tvb, packet->frame.subframe2 + 1) ^ packet->scm_udid[1]) ^ tvb_get_guint8(message_tvb, packet->frame.subframe1 + 1));
            ct40bit <<= 8;
            ct40bit += (tvb_get_guint8(message_tvb, packet->frame.subframe2 + 0) ^ packet->scm_udid[0]) ^ OPENSAFETY_DEFAULT_DOMAIN ^ tvb_get_guint8(message_tvb, packet->frame.subframe1 + 0);
            ct40bit <<= 8;
            ct40bit += (tvb_get_guint8(message_tvb, packet->frame.subframe2 + 2) ^ packet->scm_udid[2]);
            ct40bit <<= 8;
            ct40bit += tvb_get_guint8(message_tvb, packet->frame.subframe1 + 3);

            item = proto_tree_add_uint64(spdo_tree, hf_oss_spdo_ct_40bit, message_tvb, 0, 0, ct40bit);
            proto_item_set_generated(item);

            packet->payload.spdo->counter.b40 = ct40bit;
            if ( global_opensafety_debug_verbose )
                expert_add_info ( pinfo, item, &ei_40bit_default_domain );
        }
        proto_item_set_generated(item);

        if ( b_ID == OPENSAFETY_MSG_SPDO_DATA_WITH_TIME_RESPONSE )
        {
            proto_item_append_text(diritem, " (Safety Node: %03d)", taddr);
            proto_tree_add_uint(spdo_tree, hf_oss_spdo_time_request, message_tvb,
                    OSS_FRAME_POS_ADDR + packet->frame.subframe2 + 4, 1, tr);
            packet->payload.spdo->timerequest = taddr;

            opensafety_packet_node ( message_tvb, pinfo, spdo_tree, hf_oss_spdo_time_request_to, taddr,
                    OSS_FRAME_POS_ADDR + packet->frame.subframe2 + 3, packet->frame.subframe2, sdn );
        }
        else
        {
            item = proto_tree_add_uint(spdo_tree, hf_oss_spdo_feature_flags,
                    message_tvb, OSS_FRAME_POS_ADDR + packet->frame.subframe2 + 4, 1, spdoFlags << 2);

            spdo_flags_tree = proto_item_add_subtree(item, ett_opensafety_spdo_flags);

            proto_tree_add_boolean(spdo_flags_tree, hf_oss_spdo_feature_flag_40bit_available, message_tvb,
                    OSS_FRAME_POS_ADDR + packet->frame.subframe2 + 4, 1,
                    packet->payload.spdo->flags.requested40bit ? OPENSAFETY_SPDO_FEAT_40BIT_AVAIL << 2 : 0 );
            proto_tree_add_boolean(spdo_flags_tree, hf_oss_spdo_feature_flag_40bit_used, message_tvb,
                    OSS_FRAME_POS_ADDR + packet->frame.subframe2 + 4, 1,
                    packet->payload.spdo->flags.enabled40bit ? OPENSAFETY_SPDO_FEAT_40BIT_USED << 2 : 0 );
        }
    }

    if ( dataLength > 0 )
    {
        dissect_data_payload(spdo_tree, message_tvb, pinfo, OSS_FRAME_POS_ID + 3, dataLength, OPENSAFETY_SPDO_MESSAGE_TYPE);
    }
}

static void dissect_opensafety_ssdo_payload ( packet_info *pinfo, tvbuff_t *new_tvb, proto_tree *ssdo_payload, guint8 sacmd )
{
    guint       dataLength   = 0, ctr = 0, n = 0, nCRCs = 0;
    guint8      ssdoSubIndex = 0;
    guint16     ssdoIndex    = 0, dispSSDOIndex = 0;
    guint32     sodLength    = 0, entry = 0;
    proto_item *item;
    proto_tree *sod_tree, *ext_tree;

    dataLength = tvb_captured_length(new_tvb);

    ssdoIndex = tvb_get_letohs(new_tvb, 0);

    sodLength = tvb_get_letohl(new_tvb, 4);

    /* first check for extended parameter */
    if ( dataLength == 16 || sodLength == ( dataLength - 16 ) || ssdoIndex == 0x0101 )
    {
        /* extended parameter header & data */
        item = proto_tree_add_string_format(ssdo_payload, hf_oss_ssdo_extpar,
                                            new_tvb, 0, dataLength, "", "Extended Parameter Set: %s",
                                            (dataLength == 16 ? "Header only" : "Header & Data") );
        ext_tree = proto_item_add_subtree(item, ett_opensafety_ssdo_extpar);

        proto_tree_add_item(ext_tree, hf_oss_ssdo_extpar_parset,  new_tvb, 0, 1, ENC_BIG_ENDIAN );
        proto_tree_add_item(ext_tree, hf_oss_ssdo_extpar_version, new_tvb, 1, 1, ENC_BIG_ENDIAN );
        proto_tree_add_item(ext_tree, hf_oss_ssdo_extpar_saddr,   new_tvb, 2, 2, ENC_LITTLE_ENDIAN );

        proto_tree_add_uint_format_value(ext_tree, hf_oss_ssdo_extpar_length,
                                         new_tvb, 4, 4, sodLength, "0x%04X (%d octets)",
                                         sodLength, sodLength );

        proto_tree_add_item(ext_tree, hf_oss_ssdo_extpar_crc,    new_tvb,  8, 4, ENC_LITTLE_ENDIAN );
        proto_tree_add_item(ext_tree, hf_oss_ssdo_extpar_tstamp, new_tvb, 12, 4, ENC_LITTLE_ENDIAN );

        if ( dataLength != 16 )
        {
            item = proto_tree_add_item(ext_tree, hf_oss_ssdo_extpar_data, new_tvb, 16, dataLength - 16, ENC_NA );

            if ( ( dataLength - sodLength ) != 16 )
                expert_add_info ( pinfo, item, &ei_message_reassembly_size_differs_from_header );
        }
    }
    else
    {
        /* If == upload, it is most likely a par upload */
        if ( sacmd == OPENSAFETY_MSG_SSDO_UPLOAD_SEGMENT_END && ( dataLength % 4 == 0 ) )
        {

            item = proto_tree_add_uint_format_value(ssdo_payload, hf_oss_ssdo_sod_index, new_tvb,
                                                    0, 0,  0x1018, "0x%04X (%s)", 0x1018,
                                                    val_to_str_ext_const( ((guint32) (0x1018 << 16) ),
                                                                          &opensafety_sod_idx_names_ext, "Unknown") );
            sod_tree = proto_item_add_subtree(item, ett_opensafety_ssdo_sodentry);
            proto_item_set_generated(item);

            item = proto_tree_add_uint_format_value(sod_tree, hf_oss_ssdo_sod_subindex, new_tvb, 0, 0,
                                                    0x06, "0x%02X (%s)", 0x06,
                                                    val_to_str_ext_const(((guint32) (0x1018 << 16) +  0x06),
                                                                         &opensafety_sod_idx_names_ext, "Unknown") );
            proto_item_set_generated(item);

            proto_tree_add_item( sod_tree, hf_oss_sod_par_timestamp, new_tvb, 0, 4, ENC_LITTLE_ENDIAN );

            /* This is to avoid a compiler loop optimization warning */
            nCRCs = dataLength / 4;
            for ( ctr = 1; ctr < nCRCs; ctr++ )
            {
                entry = tvb_get_letohl ( new_tvb, ctr * 4 );
                proto_tree_add_uint_format_value ( sod_tree, hf_oss_sod_par_checksum, new_tvb, ctr * 4,
                        4, entry, "[#%d] 0x%08X", ctr, entry );
            }
        }
        /* If != upload, it is most likely a 101A download */
        else
        {

            /* normal parameter set */
            for ( ctr = 0; ctr < dataLength; ctr++ )
            {
                ssdoIndex = tvb_get_letohs(new_tvb, ctr);
                ssdoSubIndex = tvb_get_guint8(new_tvb, ctr + 2);
                dispSSDOIndex = ssdoIndex;

                if ( ssdoIndex >= 0x1400 && ssdoIndex <= 0x17FE )
                    dispSSDOIndex = 0x1400;
                else if ( ssdoIndex >= 0x1800 && ssdoIndex <= 0x1BFE )
                    dispSSDOIndex = 0x1800;
                else if ( ssdoIndex >= 0x1C00 && ssdoIndex <= 0x1FFE )
                    dispSSDOIndex = 0x1C00;
                else if ( ssdoIndex >= 0xC000 && ssdoIndex <= 0xC3FE )
                    dispSSDOIndex = 0xC000;

                item = proto_tree_add_uint_format_value(ssdo_payload, hf_oss_ssdo_sod_index, new_tvb,
                                                        ctr, 2,  ssdoIndex, "0x%04X (%s)", ssdoIndex,
                                                        val_to_str_ext_const( ((guint32) (dispSSDOIndex << 16) ),
                                                                              &opensafety_sod_idx_names_ext, "Unknown") );
                if ( ssdoIndex != dispSSDOIndex )
                    proto_item_set_generated ( item );

                if ( ssdoIndex < 0x1000 || ssdoIndex > 0xE7FF )
                    expert_add_info ( pinfo, item, &ei_payload_unknown_format );

                sod_tree = proto_item_add_subtree(item, ett_opensafety_ssdo_sodentry);

                if ( ssdoSubIndex != 0 )
                {
                    proto_tree_add_uint_format_value(sod_tree, hf_oss_ssdo_sod_subindex, new_tvb, ctr + 2, 1,
                                                     ssdoSubIndex, "0x%02X (%s)", ssdoSubIndex,
                                                     val_to_str_ext_const(((guint32) (ssdoIndex << 16) + ssdoSubIndex),
                                                                          &opensafety_sod_idx_names_ext, "Unknown") );
                }
                else
                    proto_tree_add_uint_format_value(sod_tree, hf_oss_ssdo_sod_subindex, new_tvb, ctr + 2, 1,
                                                 ssdoSubIndex, "0x%02X", ssdoSubIndex );
                ctr += 2;

                /* reading real size */
                sodLength = tvb_get_letohl ( new_tvb, ctr + 1 );
                if ( sodLength > (dataLength - ctr) )
                    sodLength = 0;

                if ( ( sodLength + 4 + ctr ) > dataLength )
                    break;

                if ( ssdoIndex == OPENSAFETY_SOD_DVI && ssdoSubIndex == 0x06 )
                {
                    proto_tree_add_item( sod_tree, hf_oss_sod_par_timestamp, new_tvb, ctr + 5, 4, ENC_LITTLE_ENDIAN );

                    /* This is to avoid a compiler loop optimization warning */
                    nCRCs = sodLength / 4;
                    for ( n = 1; n < nCRCs; n++ )
                    {
                        entry = tvb_get_letohl ( new_tvb, ctr + 5 + ( n * 4 ) );
                        proto_tree_add_uint_format_value ( sod_tree, hf_oss_sod_par_checksum, new_tvb,
                                (ctr + 5 + ( n * 4 ) ), 4, entry, "[#%d] 0x%08X", n, entry );
                    }
                } else if ( ssdoIndex == OPENSAFETY_SOD_DVI && ssdoSubIndex == 0x07 ) {
                    proto_tree_add_item( sod_tree, hf_oss_sod_par_timestamp, new_tvb, ctr + 5, 4, ENC_LITTLE_ENDIAN );
                } else if ( ( dispSSDOIndex == OPENSAFETY_SOD_RXMAP || dispSSDOIndex == OPENSAFETY_SOD_TXMAP ) && ssdoSubIndex != 0x0 ) {
                    proto_tree_add_uint(sod_tree, hf_oss_ssdo_sodentry_size, new_tvb, ctr + 1, 4, sodLength );
                    item = proto_tree_add_item(sod_tree, hf_oss_ssdo_sodmapping, new_tvb, ctr + 5, sodLength, ENC_NA );
                    ext_tree = proto_item_add_subtree(item, ett_opensafety_sod_mapping);

                    proto_tree_add_item(ext_tree, hf_oss_ssdo_sodmapping_bits, new_tvb, ctr + 5, 1, ENC_NA);

                    proto_tree_add_item(ext_tree, hf_oss_ssdo_sod_index, new_tvb, ctr + 7, 2, ENC_LITTLE_ENDIAN);
                    proto_tree_add_item(ext_tree, hf_oss_ssdo_sod_subindex, new_tvb, ctr + 6, 1, ENC_NA);

                } else {
                    proto_tree_add_uint(sod_tree, hf_oss_ssdo_sodentry_size, new_tvb, ctr + 1, 4, sodLength );
                    if ( sodLength > 0 )
                        proto_tree_add_item(sod_tree, hf_oss_ssdo_sodentry_data, new_tvb, ctr + 5, sodLength, ENC_NA );
                }
                ctr += sodLength + 4;
        }
        }
    }


}

static void
dissect_opensafety_ssdo_message(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *opensafety_tree,
        opensafety_packet_info * packet, proto_item * opensafety_item )
{
    proto_item    *item;
    proto_tree    *ssdo_tree, *ssdo_payload;
    guint16        taddr                = 0, sdn = 0, server = 0, client = 0, n = 0, ct = 0;
    guint32        abortcode, ssdoIndex = 0, ssdoSubIndex = 0, payloadSize, fragmentId = 0, entry = 0;
    guint8         db0Offset, db0, payloadOffset, preload;
    guint          dataLength;
    gint           calcDataLength;
    gboolean       isResponse, saveFragmented;
    tvbuff_t      *new_tvb              = NULL;
    fragment_head *frag_msg             = NULL;

    static int * const ssdo_sacmd_flags[] = {
            &hf_oss_ssdo_sacmd_end_segment,
            &hf_oss_ssdo_sacmd_initiate,
            &hf_oss_ssdo_sacmd_toggle,
            &hf_oss_ssdo_sacmd_segmentation,
            &hf_oss_ssdo_sacmd_abort_transfer,
            &hf_oss_ssdo_sacmd_preload,
            &hf_oss_ssdo_sacmd_access_type,
            NULL
    };

    dataLength = tvb_get_guint8(message_tvb, OSS_FRAME_POS_LEN + packet->frame.subframe1);

    db0Offset = packet->frame.subframe1 + OSS_FRAME_POS_DATA;
    db0 = tvb_get_guint8(message_tvb, db0Offset);
    ssdoIndex = 0;
    ssdoSubIndex = 0;

    /* Response is determined by the openSAFETY message field */
    isResponse = ( ( OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1) & 0x04 ) == 0x04 );

    if ( packet->scm_udid_valid )
    {
        /* taddr is the 4th octet in the second frame */
        taddr = OSS_FRAME_ADDR_T2(message_tvb, packet->frame.subframe2 + 3, packet->scm_udid[3], packet->scm_udid[4]);
        sdn =  ( OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1) ^
                        ( OSS_FRAME_ADDR_T2(message_tvb, packet->frame.subframe2, packet->scm_udid[0], packet->scm_udid[1]) ) );

        opensafety_packet_sendreceiv ( message_tvb, pinfo, opensafety_tree, opensafety_item, packet, taddr,
                packet->frame.subframe2 + 3, OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1),
                packet->frame.subframe1, packet->frame.subframe2, sdn );
    }
    else if ( ! isResponse )
    {
        opensafety_packet_sender ( message_tvb, pinfo, opensafety_tree, opensafety_item, packet,
                OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1), packet->frame.subframe1,
                packet->frame.subframe2, -1 * ( ( OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1) ) ^
                        ( OSS_FRAME_ADDR_T2(message_tvb, packet->frame.subframe2, packet->scm_udid[0], packet->scm_udid[1]) ) ) );
    }
    else if ( isResponse )
    {
        opensafety_packet_receiver ( message_tvb, pinfo, opensafety_tree, opensafety_item, packet,
                OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1), packet->frame.subframe1,
                packet->frame.subframe2, -1 * ( ( OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1) ) ^
                        ( OSS_FRAME_ADDR_T2(message_tvb, packet->frame.subframe2, packet->scm_udid[0], packet->scm_udid[1]) ) ) );
    }

    ssdo_tree = opensafety_packet_payloadtree ( pinfo, message_tvb, opensafety_tree, packet, ett_opensafety_ssdo );

    opensafety_packet_response ( message_tvb, ssdo_tree, packet, isResponse );

    packet->payload.ssdo->sacmd.toggle = ( db0 & OPENSAFETY_SSDO_SACMD_TGL ) == OPENSAFETY_SSDO_SACMD_TGL;
    packet->payload.ssdo->sacmd.abort_transfer = ( db0 & OPENSAFETY_SSDO_SACMD_ABRT ) == OPENSAFETY_SSDO_SACMD_ABRT;
    packet->payload.ssdo->sacmd.preload = ( db0 & OPENSAFETY_SSDO_SACMD_PRLD ) == OPENSAFETY_SSDO_SACMD_PRLD;
    packet->payload.ssdo->sacmd.read_access = ( db0 & OPENSAFETY_SSDO_DOWNLOAD ) == OPENSAFETY_SSDO_DOWNLOAD;
    packet->payload.ssdo->sacmd.initiate = ( db0 & OPENSAFETY_SSDO_SACMD_INI ) == OPENSAFETY_SSDO_SACMD_INI;
    packet->payload.ssdo->sacmd.segmented = ( db0 & OPENSAFETY_SSDO_SACMD_SEG ) == OPENSAFETY_SSDO_SACMD_SEG;
    packet->payload.ssdo->sacmd.end_segment = ( db0 & OPENSAFETY_SSDO_SACMD_ENSG ) == OPENSAFETY_SSDO_SACMD_ENSG;

    if ( isResponse )
    {
        opensafety_packet_node ( message_tvb, pinfo, ssdo_tree, hf_oss_ssdo_client,
                OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1),
                packet->frame.subframe1, packet->frame.subframe2, sdn );
        client = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1);

        if ( packet->scm_udid_valid )
        {
            proto_tree_add_uint(ssdo_tree, hf_oss_ssdo_server, message_tvb, packet->frame.subframe2 + 3, 2, taddr);
            server = taddr;
        }
    }
    else if ( ! isResponse )
    {
        proto_tree_add_uint(ssdo_tree, hf_oss_ssdo_server, message_tvb, packet->frame.subframe1, 2, OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1));
        server = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1);
        if ( packet->scm_udid_valid )
        {
            opensafety_packet_node ( message_tvb, pinfo, ssdo_tree, hf_oss_ssdo_client,
                    taddr, packet->frame.subframe2 + 3, packet->frame.subframe2, sdn );
            client = taddr;
        }
    }

    /* Toggle bit must be removed, otherwise the values cannot be displayed correctly */
    if ( packet->payload.ssdo->sacmd.toggle )
        db0 &= (~OPENSAFETY_SSDO_SACMD_TGL);
    proto_tree_add_bitmask(ssdo_tree, message_tvb, db0Offset, hf_oss_ssdo_sacmd,
            ett_opensafety_ssdo_sacmd, ssdo_sacmd_flags, ENC_NA);

    col_append_fstr(pinfo->cinfo, COL_INFO, ", SACMD: %s", val_to_str_const(db0, opensafety_ssdo_sacmd_values, " "));

    payloadOffset = db0Offset + 1;

    ct = tvb_get_guint8(message_tvb, packet->frame.subframe1 + 3);
    if ( packet->scm_udid_valid )
    {
        ct = (guint16)((tvb_get_guint8(message_tvb, packet->frame.subframe2 + 2) ^ packet->scm_udid[2]) << 8);
        ct += (tvb_get_guint8(message_tvb, packet->frame.subframe1 + 3));
    }

    proto_tree_add_uint(ssdo_tree, hf_oss_ssdo_sano, message_tvb, packet->frame.subframe1 + 3, 1, ct );

    /* Evaluate preload field [field TR] */
    if ( packet->scm_udid_valid && packet->payload.ssdo->sacmd.preload && isResponse )
    {
        /* Preload info are the higher 6 bit of the TR field */
        preload = ( (tvb_get_guint8(message_tvb, packet->frame.subframe2 + 4) ^ packet->scm_udid[4]) & 0xFC ) >> 2;

        if ( packet->payload.ssdo->sacmd.initiate )
        {
            /* Use the lower 4 bits from the preload as size */
            proto_tree_add_uint_format_value(ssdo_tree, hf_oss_ssdo_preload_queue, message_tvb, packet->frame.subframe2 + 4, 1,
                    preload & 0x0F, "%d", preload & 0x0F );
        }
        else
        {
            /* The highest 2 bits of information contain an error flag */
            item = proto_tree_add_item(ssdo_tree, hf_oss_ssdo_preload_error, message_tvb, packet->frame.subframe2 + 4, 1, ENC_NA );
            if ( (preload & 0x30) == 0x30 )
                proto_item_append_text(item, " (SOD Access Request Number is last successful)" );
        }
    }

    /* When the following clause is met, DB1,2 contain the SOD index, and DB3 the SOD subindex */
    if ( packet->payload.ssdo->sacmd.initiate && !packet->payload.ssdo->sacmd.abort_transfer )
    {
        ssdoIndex = tvb_get_letohs(message_tvb, db0Offset + 1);
        ssdoSubIndex = tvb_get_guint8(message_tvb, db0Offset + 3);

        proto_tree_add_uint_format_value(ssdo_tree, hf_oss_ssdo_sod_index, message_tvb, db0Offset + 1, 2,
                ssdoIndex, "0x%04X (%s)", ssdoIndex,
                val_to_str_ext_const(((guint32) (ssdoIndex << 16)), &opensafety_sod_idx_names_ext, "Unknown") );
        col_append_fstr(pinfo->cinfo, COL_INFO, " [%s", val_to_str_ext_const(((guint32) (ssdoIndex << 16)), &opensafety_sod_idx_names_ext, "Unknown"));

        /* Some SOD downloads (0x101A for instance) don't have sub-indeces */
        if ( ssdoSubIndex != 0x0 )
        {
            proto_tree_add_uint_format_value(ssdo_tree, hf_oss_ssdo_sod_subindex, message_tvb, db0Offset + 3, 1,
                ssdoSubIndex, "0x%02X (%s)", ssdoSubIndex,
                val_to_str_ext_const(((guint32) (ssdoIndex << 16) + ssdoSubIndex), &opensafety_sod_idx_names_ext, "Unknown") );
            col_append_fstr(pinfo->cinfo, COL_INFO, " - %s",
                    val_to_str_ext_const(((guint32) (ssdoIndex << 16) + ssdoSubIndex), &opensafety_sod_idx_names_ext, "Unknown"));
        }
        col_append_str(pinfo->cinfo, COL_INFO, "]");
        payloadOffset += 3;
    }

    if ( packet->payload.ssdo->sacmd.abort_transfer )
    {
        abortcode = tvb_get_letohl(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 4);

        proto_tree_add_uint_format_value(ssdo_tree, hf_oss_ssdo_abort_code, message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 4, 4, abortcode,
                "0x%04X %04X - %s", (guint16)(abortcode >> 16), (guint16)(abortcode),
                val_to_str_ext_const(abortcode, &opensafety_abort_codes_ext, "Unknown"));
        col_append_fstr(pinfo->cinfo, COL_INFO, " - %s", val_to_str_ext_const(abortcode, &opensafety_abort_codes_ext, "Unknown"));


    } else {
        /* Either the SSDO msg is a response, then data is sent by the server and only in uploads,
         * or the message is a request, then data is coming from the client and payload data is
         * sent in downloads. Data is only sent in initiate, segmented or end-segment messages */
        if ( ( packet->payload.ssdo->sacmd.initiate || packet->payload.ssdo->sacmd.segmented || packet->payload.ssdo->sacmd.end_segment ) &&
             ( ( isResponse && !packet->payload.ssdo->sacmd.read_access ) ||
                     ( !isResponse && packet->payload.ssdo->sacmd.read_access ) ) )
        {
            saveFragmented = pinfo->fragmented;
            if ( server != 0 && client != 0 )
                fragmentId = (guint32)((((guint32)client) << 16 ) + server );

            /* If payload data has to be calculated, either a total size is given, or not */
            if ( packet->payload.ssdo->sacmd.segmented && packet->payload.ssdo->sacmd.initiate )
            {

                payloadOffset += 4;

                /* reading real size */
                payloadSize = tvb_get_letohl(message_tvb, payloadOffset - 4);

                calcDataLength = dataLength - (payloadOffset - db0Offset);

                item = proto_tree_add_uint_format_value(ssdo_tree, hf_oss_ssdo_payload_size, message_tvb, payloadOffset - 4, 4,
                        payloadSize, "%d octets total (%d octets in this frame)", payloadSize, calcDataLength);

                if ( calcDataLength >= 0 )
                {
                    if ( fragmentId != 0 && packet->payload.ssdo->sacmd.segmented )
                    {
                        pinfo->fragmented = TRUE;
                        frag_msg = fragment_add_seq_check(&os_reassembly_table, message_tvb, payloadOffset, pinfo,
                                                          fragmentId, NULL, 0, calcDataLength, TRUE );
                        fragment_add_seq_offset ( &os_reassembly_table, pinfo, fragmentId, NULL, ct );

                        if ( frag_msg != NULL )
                        {
                            item = proto_tree_add_bytes_format_value(ssdo_tree, hf_oss_ssdo_payload, message_tvb, 0, 0, NULL, "Reassembled" );
                            proto_item_set_generated(item);

                            ssdo_payload = proto_item_add_subtree(item, ett_opensafety_ssdo_payload);
                            process_reassembled_data(message_tvb, 0, pinfo, "Reassembled Message", frag_msg, &oss_frag_items, NULL, ssdo_payload );
                        }
                    }

                    proto_tree_add_item(ssdo_tree, hf_oss_ssdo_payload, message_tvb, payloadOffset, calcDataLength, ENC_NA );
                } else {
                    if ( global_opensafety_debug_verbose )
                        expert_add_info_format(pinfo, item, &ei_payload_length_not_positive,
                                                    "Calculation for payload length yielded non-positive result [%d]", (guint) calcDataLength );
                }
            }
            else
            {
                payloadSize = dataLength - (payloadOffset - db0Offset);
                if ((gint)dataLength < (payloadOffset - db0Offset))
                {
                    if ( global_opensafety_debug_verbose )
                        expert_add_info_format(pinfo, opensafety_item, &ei_payload_length_not_positive,
                                                    "Calculation for payload length yielded non-positive result [%d]", (gint)payloadSize );
                    return;
                }

                if ( fragmentId != 0 && packet->payload.ssdo->sacmd.segmented )
                {
                    pinfo->fragmented = TRUE;

                    frag_msg = fragment_add_seq_check(&os_reassembly_table, message_tvb, payloadOffset, pinfo,
                                                      fragmentId, NULL, ct, payloadSize,
                                                      packet->payload.ssdo->sacmd.end_segment ? FALSE : TRUE );
                }

                if ( frag_msg )
                {
                    item = proto_tree_add_bytes_format_value(ssdo_tree, hf_oss_ssdo_payload, message_tvb,
                                                             0, 0, NULL, "Reassembled" );
                    proto_item_set_generated(item);
                    ssdo_payload = proto_item_add_subtree(item, ett_opensafety_ssdo_payload);

                    new_tvb = process_reassembled_data(message_tvb, 0, pinfo, "Reassembled Message", frag_msg,
                                                       &oss_frag_items, NULL, ssdo_payload );
                    if ( packet->payload.ssdo->sacmd.end_segment && new_tvb )
                    {
                        item = proto_tree_add_uint_format_value(ssdo_payload, hf_oss_ssdo_payload_size, message_tvb, 0, 0,
                                                                payloadSize, "%d octets (over all fragments)", frag_msg->len);
                        proto_item_set_generated(item);

                        col_append_str(pinfo->cinfo, COL_INFO, " (Message Reassembled)" );
                        dissect_opensafety_ssdo_payload ( pinfo, new_tvb, ssdo_payload, db0 );
                    }
                }
                else
                {
                    item = proto_tree_add_uint_format_value(ssdo_tree, hf_oss_ssdo_payload_size, message_tvb, 0, 0, payloadSize,
                            "%d octets", payloadSize);
                    proto_item_set_generated(item);

                    if ( ssdoIndex == OPENSAFETY_SOD_DVI && ssdoSubIndex == 0x06 )
                    {
                        proto_tree_add_item( ssdo_tree, hf_oss_sod_par_timestamp, message_tvb, payloadOffset, 4, ENC_LITTLE_ENDIAN );
                        for ( n = 4; n < payloadSize; n+=4 )
                        {
                            entry = tvb_get_letohl ( message_tvb, payloadOffset + n );
                            proto_tree_add_uint_format_value ( ssdo_tree, hf_oss_sod_par_checksum, message_tvb, (payloadOffset + n ),
                                    4, entry, "[#%d] 0x%08X", ( n / 4 ), entry );
                        }
                    } else if ( ssdoIndex == OPENSAFETY_SOD_DVI && ssdoSubIndex == 0x07 ) {
                        proto_tree_add_item ( ssdo_tree, hf_oss_sod_par_timestamp, message_tvb, payloadOffset, 4, ENC_LITTLE_ENDIAN );
                    } else
                        proto_tree_add_item(ssdo_tree, hf_oss_ssdo_payload, message_tvb, payloadOffset, payloadSize, ENC_NA );
                }
            }

            pinfo->fragmented = saveFragmented;
        }
    }
}

static void
opensafety_parse_scm_udid ( tvbuff_t* tvb, packet_info *pinfo, proto_tree *tree,
        opensafety_packet_info *packet, guint offset )
{
    proto_item * item = NULL;
    gchar      *scm_udid_test = NULL;

    item = proto_tree_add_item(tree, hf_oss_snmt_udid, tvb, offset, 6, ENC_NA);

    scm_udid_test = tvb_bytes_to_str_punct(pinfo->pool, tvb, offset, 6, ':' );

    if ( scm_udid_test != NULL && strlen( scm_udid_test ) == 17 )
    {
        if ( g_strcmp0("00:00:00:00:00:00", scm_udid_test ) != 0 )
        {
            packet->payload.snmt->scm_udid = scm_udid_test;

            if ( ( global_scm_udid_autoset == TRUE ) &&  ( memcmp ( global_scm_udid, scm_udid_test, 17 ) != 0 ) )
            {
                if ( local_scm_udid == NULL || memcmp ( local_scm_udid, scm_udid_test, 17 ) != 0 )
                {
                    local_scm_udid = wmem_strdup(wmem_file_scope(), scm_udid_test );
                    if ( global_opensafety_debug_verbose )
                        expert_add_info_format(pinfo, item, &ei_scmudid_autodetected,
                                "Auto detected payload as SCM UDID [%s].", local_scm_udid);
                }
            }
        }
    }
}

static void
dissect_opensafety_snmt_message(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *opensafety_tree,
        opensafety_packet_info *packet, proto_item * opensafety_item )
{
    proto_tree *snmt_tree;
    guint16     addr, taddr, sdn;
    guint8      db0, byte, errcode;
    guint       dataLength;

    dataLength = OSS_FRAME_LENGTH_T(message_tvb, packet->frame.subframe1);

    /* addr is the first field, as well as the recipient of the message */
    addr = packet->saddr;

    /* taddr is the 4th octet in the second frame */
    taddr = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe2 + 3);
    /* domain is xor'ed on the first field in the second frame. As this is also addr, it is easy to obtain */
    sdn = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe2) ^ addr;
    packet->sdn = sdn;

    db0 = -1;
    if (dataLength > 0)
        db0 = tvb_get_guint8(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA);

    packet->msg_id = OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1);

    if ( ( packet->msg_id == OPENSAFETY_MSG_SNMT_SERVICE_RESPONSE ) &&
         ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SCM_SET_TO_STOP) == 0 ||
           (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SCM_SET_TO_OP) == 0 ) )
    {
        opensafety_packet_receiver( message_tvb, pinfo, opensafety_tree, opensafety_item, packet, addr,
                OSS_FRAME_POS_ADDR + packet->frame.subframe1, packet->frame.subframe2, sdn );
    }
    else
    {
        opensafety_packet_sendreceiv ( message_tvb, pinfo, opensafety_tree, opensafety_item, packet, taddr,
                packet->frame.subframe2 + 3, addr, OSS_FRAME_POS_ADDR + packet->frame.subframe1,
                packet->frame.subframe2, sdn );
    }

    snmt_tree = opensafety_packet_payloadtree ( pinfo, message_tvb, opensafety_tree, packet, ett_opensafety_snmt );
    /* Just a precaution, cause payloadtree actually sets the snmt pointer */
    if ( packet->payload.snmt == NULL )
        return;

    if ( ( packet->msg_id == OPENSAFETY_MSG_SNMT_SERVICE_RESPONSE ) ||
         ( packet->msg_id == OPENSAFETY_MSG_SNMT_SERVICE_REQUEST ) )
        packet->payload.snmt->ext_msg_id = db0;

    opensafety_packet_response(message_tvb, snmt_tree, packet, ( packet->msg_id & 0x04 ) == 0x04 );

    if ( packet->is_request )
    {
        proto_tree_add_uint(snmt_tree, hf_oss_snmt_master, message_tvb, packet->frame.subframe2 + 3, 2, taddr);
        proto_tree_add_uint(snmt_tree, hf_oss_snmt_slave, message_tvb, OSS_FRAME_POS_ADDR + packet->frame.subframe1, 2, addr);
    }
    else
    {
        proto_tree_add_uint(snmt_tree, hf_oss_snmt_master, message_tvb, OSS_FRAME_POS_ADDR + packet->frame.subframe1, 2, addr);
        proto_tree_add_uint(snmt_tree, hf_oss_snmt_slave, message_tvb, packet->frame.subframe2 + 3, 2, taddr);
    }

    /* Handle Acknowledge and Fail specifically */
    if ( ( ( db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_ACKNOWLEDGE) == 0 ) || ( db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_FAIL) == 0 )
    {
        byte = tvb_get_guint8(message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1);

        /* Handle a normal SN Fail */
        if ( byte != OPENSAFETY_ERROR_GROUP_ADD_PARAMETER )
        {
            if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_FAIL) == 0 )
            {
                proto_tree_add_uint(snmt_tree, hf_oss_snmt_service_id, message_tvb,
                        OSS_FRAME_POS_DATA + packet->frame.subframe1, 1, packet->payload.snmt->ext_msg_id);
                col_append_fstr(pinfo->cinfo, COL_INFO, ", %s",
                        val_to_str_const(packet->payload.snmt->ext_msg_id, opensafety_message_service_type, "Unknown"));
            }
            else if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_ACKNOWLEDGE) == 0 )
            {
                proto_tree_add_uint(snmt_tree, hf_oss_snmt_service_id, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1, 1, db0);
                col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", val_to_str_const(db0, opensafety_message_service_type, "Unknown"));
            }

            proto_tree_add_uint_format_value(snmt_tree, hf_oss_snmt_error_group, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1, 1,
                    byte, "%s", ( byte == 0 ? "Device" : val_to_str(byte, opensafety_sn_fail_error_group, "Reserved [%d]" ) ) );

            errcode = tvb_get_guint8(message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 2);
            proto_tree_add_uint_format_value(snmt_tree, hf_oss_snmt_error_code, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 2, 1,
                    errcode, "%s [%d]", ( errcode == 0 ? "Default" : "Vendor Specific" ), errcode );

            col_append_fstr(pinfo->cinfo, COL_INFO, " - Group: %s; Code: %s",
                ( byte == 0 ? "Device" : val_to_str(byte, opensafety_sn_fail_error_group, "Reserved [%d]" ) ),
                ( errcode == 0 ? "Default" : "Vendor Specific" )
            );

            packet->payload.snmt->add_param.exists = FALSE;
            packet->payload.snmt->error_code = errcode;
        }
        else
        {
            if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_FAIL) == 0 )
            {
                proto_tree_add_uint_format_value(snmt_tree, hf_oss_snmt_service_id, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1, 1,
                        packet->payload.snmt->ext_msg_id, "%s [Request via SN Fail] (0x%02X)",
                        val_to_str_const(byte, opensafety_sn_fail_error_group, "Unknown"), packet->payload.snmt->ext_msg_id);
                col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", val_to_str_const(byte, opensafety_sn_fail_error_group, "Unknown"));
            } else if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_ACKNOWLEDGE) == 0 )
            {
                proto_tree_add_uint_format_value(snmt_tree, hf_oss_snmt_service_id, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1, 1,
                        packet->payload.snmt->ext_msg_id, "Additional parameter missing [Response via SN Acknowledge] (0x%02X)", packet->payload.snmt->ext_msg_id);
                col_append_str(pinfo->cinfo, COL_INFO, ", Additional parameter missing");
            }

            errcode = tvb_get_guint8(message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 2);
            packet->payload.snmt->add_param.exists = TRUE;
            packet->payload.snmt->add_param.id = errcode;
            packet->payload.snmt->add_param.set = ( errcode & 0x0F ) + 1;
            packet->payload.snmt->add_param.full = ( ( errcode & 0xF0 ) == 0xF0 );

            /* Handle an additional parameter request */
            proto_tree_add_uint(snmt_tree, hf_oss_ssdo_extpar_parset, message_tvb,
                    OSS_FRAME_POS_DATA + packet->frame.subframe1 + 2, 1, ( errcode & 0x0F ) + 1 );

            proto_tree_add_boolean(snmt_tree, hf_oss_snmt_param_type, message_tvb,
                    OSS_FRAME_POS_DATA + packet->frame.subframe1 + 2, 1, ( ( errcode & 0xF0 ) != 0xF0 ) );
        }
    }
    else if ( (OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1) ^ OPENSAFETY_MSG_SNMT_SERVICE_RESPONSE) == 0 )
    {
        proto_tree_add_uint(snmt_tree, hf_oss_snmt_service_id, message_tvb,
                OSS_FRAME_POS_DATA + packet->frame.subframe1, 1, packet->payload.snmt->ext_msg_id);
        col_append_fstr(pinfo->cinfo, COL_INFO, ", %s",
                val_to_str_const(packet->payload.snmt->ext_msg_id, opensafety_message_service_type, "Unknown"));

        if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_ASSIGNED_UDID_SCM) == 0 )
        {
            opensafety_parse_scm_udid ( message_tvb, pinfo, snmt_tree, packet, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1 );
        }
        else if ( ( db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_ASSIGNED_ADDITIONAL_SADR) == 0 )
        {
            packet->payload.snmt->add_saddr.actual = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 1);
            proto_tree_add_uint(snmt_tree, hf_oss_snmt_ext_addsaddr, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1, 2,
                    packet->payload.snmt->add_saddr.actual );

            packet->payload.snmt->add_saddr.additional = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 3);
            proto_tree_add_uint(snmt_tree, hf_oss_snmt_ext_addtxspdo, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 3, 2,
                    packet->payload.snmt->add_saddr.additional);

            col_append_fstr(pinfo->cinfo, COL_INFO, " [0x%04X => 0x%04X]",
                    OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 1),
                    OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 3));
        }
        else if ( ( db0 ^ OPENSAFETY_MSG_SNMT_EXT_ASSIGNED_INIT_CT) == 0 )
        {
            packet->payload.snmt->init_ct =
                    tvb_get_guint40(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 1, ENC_BIG_ENDIAN);
            proto_tree_add_item(snmt_tree, hf_oss_snmt_ext_initct, message_tvb,
                    packet->frame.subframe1 + OSS_FRAME_POS_DATA + 1, 5, ENC_BIG_ENDIAN );
        }
    }
    else if ( (OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1) ^ OPENSAFETY_MSG_SNMT_SERVICE_REQUEST) == 0 )
    {
        proto_tree_add_uint(snmt_tree, hf_oss_snmt_service_id, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1, 1, db0);
        col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", val_to_str_const(db0, opensafety_message_service_type, "Unknown"));

        if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SCM_SET_TO_STOP) == 0 || (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SCM_SET_TO_OP) == 0 )
        {
            proto_tree_add_uint(snmt_tree, hf_oss_snmt_scm, message_tvb, OSS_FRAME_POS_ADDR + packet->frame.subframe1, 2, addr);
            proto_tree_add_uint(snmt_tree, hf_oss_snmt_tool, message_tvb, packet->frame.subframe2 + 3, 2, taddr);
        }
        else if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_ASSIGN_UDID_SCM) == 0 )
        {
            opensafety_parse_scm_udid ( message_tvb, pinfo, snmt_tree, packet, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1 );
        }
        else if ( ( db0 ^ OPENSAFETY_MSG_SNMT_EXT_ASSIGN_INIT_CT) == 0 )
        {
            packet->payload.snmt->init_ct =
                    tvb_get_guint40(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 1, ENC_BIG_ENDIAN);
            proto_tree_add_item(snmt_tree, hf_oss_snmt_ext_initct, message_tvb,
                    packet->frame.subframe1 + OSS_FRAME_POS_DATA + 1, 5, ENC_BIG_ENDIAN );
        }
        else
        {
            if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_SET_TO_OP) == 0 )
            {
                proto_tree_add_item ( snmt_tree, hf_oss_sod_par_timestamp, message_tvb,
                        OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1, 4, ENC_LITTLE_ENDIAN );
            }
            else if ( ( db0 ^ OPENSAFETY_MSG_SNMT_EXT_ASSIGN_ADDITIONAL_SADR) == 0 )
            {
                packet->payload.snmt->add_saddr.actual = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 1);
                proto_tree_add_uint(snmt_tree, hf_oss_snmt_ext_addsaddr, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1, 2,
                        packet->payload.snmt->add_saddr.actual );

                packet->payload.snmt->add_saddr.additional = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 3);
                proto_tree_add_uint(snmt_tree, hf_oss_snmt_ext_addtxspdo, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 3, 2,
                        packet->payload.snmt->add_saddr.additional);

                col_append_fstr(pinfo->cinfo, COL_INFO, " [0x%04X => 0x%04X]",
                        OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 1),
                        OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1 + OSS_FRAME_POS_DATA + 3));
            }

        }
    }
    else if ( (OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1) ^ OPENSAFETY_MSG_SNMT_SADR_ASSIGNED) == 0 ||
            (OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1) ^ OPENSAFETY_MSG_SNMT_ASSIGN_SADR) == 0 ||
            (OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1) ^ OPENSAFETY_MSG_SNMT_RESPONSE_UDID) == 0 )
    {
        if (dataLength > 0)
        {
            packet->payload.snmt->sn_udid = wmem_strdup(pinfo->pool,
                    tvb_bytes_to_str_punct(pinfo->pool, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1, 6, ':' ) );
            proto_tree_add_item(snmt_tree, hf_oss_snmt_udid, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1, 6, ENC_NA);
        }
    }
}

static gboolean
dissect_opensafety_checksum(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *opensafety_tree,
                            opensafety_packet_info *packet )
{
    guint16     frame1_crc, frame2_crc;
    guint16     calc1_crc, calc2_crc;
    guint       dataLength, frame2Length;
    guint8     *bytesf2, *bytesf1, ctr = 0, crcType = OPENSAFETY_CHECKSUM_CRC8;
    proto_item *item;
    proto_tree *checksum_tree;
    gint        start;
    gint        length;
    gboolean    isSlim = FALSE;
    gboolean    isSNMT = FALSE;
    gboolean    isSPDO = FALSE;
    GByteArray *scmUDID = NULL;

    dataLength = OSS_FRAME_LENGTH_T(message_tvb, packet->frame.subframe1);
    start = OSS_FRAME_POS_DATA + dataLength + packet->frame.subframe1;

    if (OSS_FRAME_LENGTH_T(message_tvb, packet->frame.subframe1) > OSS_PAYLOAD_MAXSIZE_FOR_CRC8)
        frame1_crc = tvb_get_letohs(message_tvb, start);
    else
        frame1_crc = tvb_get_guint8(message_tvb, start);

    if ( packet->msg_type == OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE )
        isSlim = TRUE;
    if ( packet->msg_type == OPENSAFETY_SNMT_MESSAGE_TYPE )
        isSNMT = TRUE;
    if ( packet->msg_type == OPENSAFETY_SPDO_MESSAGE_TYPE )
        isSPDO = TRUE;

    frame2Length = (isSlim ? 0 : dataLength) + 5;

    length = (dataLength > OSS_PAYLOAD_MAXSIZE_FOR_CRC8 ? OPENSAFETY_CHECKSUM_CRC16 : OPENSAFETY_CHECKSUM_CRC8);
    item = proto_tree_add_uint_format(opensafety_tree, hf_oss_crc, message_tvb, start, length, frame1_crc,
                                      "CRC for subframe #1: 0x%04X", frame1_crc);

    checksum_tree = proto_item_add_subtree(item, ett_opensafety_checksum);

    bytesf1 = (guint8*)tvb_memdup(pinfo->pool, message_tvb, packet->frame.subframe1, dataLength + 4);

    crcType = packet->crc.type;
    calc1_crc = packet->crc.frame1;

    if ( ! isSlim && crcType == OPENSAFETY_CHECKSUM_CRC16SLIM )
        expert_add_info(pinfo, item, &ei_crc_slimssdo_instead_of_spdo );

    item = proto_tree_add_boolean(checksum_tree, hf_oss_crc_valid, message_tvb,
            packet->frame.subframe1, dataLength + 4, (frame1_crc == calc1_crc));
    proto_item_set_generated(item);
    if ( crcType == OPENSAFETY_CHECKSUM_INVALID || frame1_crc != calc1_crc )
        expert_add_info(pinfo, item, &ei_crc_frame_1_invalid );

    /* using the defines, as the values can change */
    proto_tree_add_uint(checksum_tree, hf_oss_crc_type, message_tvb, start, length, crcType );

    start = packet->frame.subframe2 + (isSlim ? 5 : dataLength + OSS_FRAME_POS_DATA + 1 );
    if (OSS_FRAME_LENGTH_T(message_tvb, packet->frame.subframe1) > OSS_PAYLOAD_MAXSIZE_FOR_CRC8)
        frame2_crc = tvb_get_letohs(message_tvb, start);
    else
        frame2_crc = tvb_get_guint8(message_tvb, start);

    /* 0xFFFF is an invalid CRC16 value, therefore valid for initialization. Needed, because
     * otherwise this function may return without setting calc2_crc, and this does not go well
     * with the compiler */
    calc2_crc = 0xFFFF;

    /* Currently SPDO 40 Bit CRC2 support is broken. Will be implemented at a later state, after
     * the first generation of openSAFETY devices using 40 bit counter are available */
    if ( isSPDO && packet->payload.spdo->flags.enabled40bit == TRUE )
        packet->scm_udid_valid = FALSE;

    /* This used to be an option. But only, because otherwise there would be three different
     * crc calculations taking place within dissection. As we could reduce this by one, the
     * global option has been changed to the simple validity question, if we have enough information
     * to calculate the second crc, meaning, if the SCM udid is known, or if we have an SNMT msg */
    if ( isSNMT || packet->scm_udid_valid )
    {
        bytesf2 = (guint8*)tvb_memdup(pinfo->pool, message_tvb, packet->frame.subframe2, frame2Length + length);

        /* SLIM SSDO messages, do not contain a payload in frame2 */
        if ( isSlim == TRUE )
            dataLength = 0;

        scmUDID = g_byte_array_new();
        packet->crc.valid2 = FALSE;
        if ( isSNMT || ( hex_str_to_bytes((local_scm_udid != NULL ? local_scm_udid : global_scm_udid), scmUDID, TRUE) && scmUDID->len == 6 ) )
        {
            if ( !isSNMT )
            {
                for ( ctr = 0; ctr < 6; ctr++ )
                    bytesf2[ctr] = bytesf2[ctr] ^ (guint8)(scmUDID->data[ctr]);
                if ( isSPDO )
                {

                    /* allow only valid SPDO flags */
                    if ( packet->msg_id == OPENSAFETY_MSG_SPDO_DATA_ONLY )
                    {
                        if ( packet->payload.spdo->flags.enabled40bit == TRUE )
                        {
                            /* we assume the OPENSAFETY_DEFAULT_DOMAIN (0x01) for 40 bit for now */
                            bytesf2[0] = bytesf2[0] ^ (bytesf2[0] ^ OPENSAFETY_DEFAULT_DOMAIN ^ bytesf1[0]);
                            bytesf2[1] = bytesf2[1] ^ (bytesf2[1] ^ bytesf1[1]);
                            bytesf2[3] = 0;
                        }
                    }
                }

                if ( isSlim || packet->frame.length == 11 )
                    frame2_crc ^= ((guint8)scmUDID->data[5]);

                /*
                 * If the second frame is 6 or 7 (slim) bytes in length, we have to decode the found
                 * frame crc again. This must be done using the byte array, as the unxor operation
                 * had to take place.
                 */
                if ( dataLength == 0 )
                {
                    if ( isSlim && length == 2 )
                        frame2_crc = ( bytesf2[6] << 8 ) + bytesf2[5];
                }

            }

            item = proto_tree_add_uint_format(opensafety_tree, hf_oss_crc, message_tvb, start, length, frame2_crc,
                    "CRC for subframe #2: 0x%04X", frame2_crc);

            checksum_tree = proto_item_add_subtree(item, ett_opensafety_checksum);

            if ( OSS_FRAME_LENGTH_T(message_tvb, packet->frame.subframe1) > OSS_PAYLOAD_MAXSIZE_FOR_CRC8 )
            {
                calc2_crc = crc16_0x755B(bytesf2, frame2Length, 0);
                if ( frame2_crc != calc2_crc )
                    calc2_crc = crc16_0x5935(bytesf2, frame2Length, 0);
            }
            else
                calc2_crc = crc8_0x2F(bytesf2, frame2Length, 0);

            item = proto_tree_add_boolean(checksum_tree, hf_oss_crc2_valid, message_tvb,
                    packet->frame.subframe2, frame2Length, (frame2_crc == calc2_crc));
            proto_item_set_generated(item);

            if ( frame2_crc != calc2_crc )
            {
                item = proto_tree_add_uint_format(checksum_tree, hf_oss_crc, message_tvb,
                        packet->frame.subframe2, frame2Length, calc2_crc, "Calculated CRC: 0x%04X", calc2_crc);
                proto_item_set_generated(item);
                expert_add_info(pinfo, item, &ei_crc_frame_2_invalid );
            }
            else
            {
                if ( global_opensafety_debug_verbose && ( isSlim || ( !isSNMT && packet->frame.length == 11 ) ) )
                    expert_add_info(pinfo, item, &ei_crc_frame_2_scm_udid_encoded );

                packet->crc.valid2 = TRUE;
            }
        }
        else
            expert_add_info(pinfo, item, &ei_crc_frame_2_unknown_scm_udid );

        g_byte_array_free(scmUDID, TRUE);
    }

    /* For a correct calculation of the second crc we need to know the scm udid.
     * If the dissection of the second frame has been triggered, we integrate the
     * crc for frame2 into the result */
    return (gboolean) (frame1_crc == calc1_crc) &&
            ( ( isSNMT || packet->scm_udid_valid ) == TRUE ? (frame2_crc == calc2_crc) : TRUE);
}

static gint
check_scmudid_validity(opensafety_packet_info *packet, tvbuff_t *message_tvb)
{
    guint8      b_ID, spdoFlags, udidLen;
    GByteArray *scmUDID = NULL;

    packet->scm_udid_valid = FALSE;
    scmUDID = g_byte_array_new();

    if ( hex_str_to_bytes((local_scm_udid != NULL ? local_scm_udid : global_scm_udid), scmUDID, TRUE) && scmUDID->len == 6 )
    {
        packet->scm_udid_valid = TRUE;

        /* Now confirm, that the xor operation was successful. The ID fields of both frames have to be the same */
        b_ID = tvb_get_guint8(message_tvb, packet->frame.subframe2 + 1) ^ (guint8)(scmUDID->data[OSS_FRAME_POS_ID]);;
        if ( ( OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1) ^ (b_ID & 0xFC)) != 0 )
            packet->scm_udid_valid = FALSE;

        /* The IDs do not match, but the SCM UDID could still be ok. This happens, if this packet
         * utilizes the 40 bit counter. Therefore we reduce the check here only to the feature
         * flags, but only if the package is a SPDO Data Only (because everything else uses 16 bit. */
        if ( packet->msg_id == OPENSAFETY_MSG_SPDO_DATA_ONLY )
        {
            spdoFlags = ( tvb_get_guint8(message_tvb, packet->frame.subframe2 + 4 ) ^ scmUDID->data[4] ) ;
            spdoFlags = ( spdoFlags >> 2 ) & OPENSAFETY_SPDO_FEATURE_FLAGS;
            if ( ( spdoFlags & OPENSAFETY_SPDO_FEAT_40BIT_USED ) == OPENSAFETY_SPDO_FEAT_40BIT_USED )
                packet->scm_udid_valid = TRUE;
        }

        if ( packet->scm_udid_valid == TRUE )
            memcpy(packet->scm_udid, scmUDID->data, 6);
    }

    udidLen = scmUDID->len;

    g_byte_array_free( scmUDID, TRUE);

    return udidLen;
}

static gboolean
dissect_opensafety_message(opensafety_packet_info *packet,
                           tvbuff_t *message_tvb, packet_info *pinfo,
                           proto_item *opensafety_item, proto_tree *opensafety_tree,
                           guint8 u_nrInPackage, guint8 previous_msg_id)
{
    guint8      ctr, udidLen;
    proto_item *item;
    gboolean    messageTypeUnknown, crcValid;

    messageTypeUnknown = FALSE;

    for ( ctr = 0; ctr < 6; ctr++ )
        packet->scm_udid[ctr] = 0;

    packet->saddr = OSS_FRAME_ADDR_T(message_tvb, packet->frame.subframe1);
    /* Sender / Receiver is determined by message type */
    packet->sender = 0;
    packet->receiver = 0;

    /* SPDO is handled below */
    if ( packet->msg_type != OPENSAFETY_SPDO_MESSAGE_TYPE )
    {
        col_append_fstr(pinfo->cinfo, COL_INFO, (u_nrInPackage > 1 ? " | %s" : "%s" ),
            val_to_str(packet->msg_id, opensafety_message_type_values, "Unknown Message (0x%02X) "));
    }

    item = proto_tree_add_uint(opensafety_tree, hf_oss_byte_offset, packet->frame.frame_tvb, 0, 1, packet->frame.byte_offset);
    proto_item_set_generated(item);

    if ( packet->msg_type == OPENSAFETY_SNMT_MESSAGE_TYPE )
    {
        proto_item_append_text(opensafety_item, ", SNMT");
        dissect_opensafety_snmt_message ( message_tvb, pinfo, opensafety_tree, packet, opensafety_item );
    }
    else
    {
        udidLen = check_scmudid_validity(packet, message_tvb);

        if ( strlen( (local_scm_udid != NULL ? local_scm_udid : global_scm_udid) ) > 0  && udidLen == 6 )
        {
            if ( local_scm_udid != NULL )
            {
                item = proto_tree_add_string(opensafety_tree, hf_oss_scm_udid_auto, message_tvb, 0, 0, local_scm_udid);
                if ( ! packet->scm_udid_valid )
                    expert_add_info(pinfo, item, &ei_message_id_field_mismatch );
            }
            else
                item = proto_tree_add_string(opensafety_tree, hf_oss_scm_udid, message_tvb, 0, 0, global_scm_udid);
            proto_item_set_generated(item);
        }

        item = proto_tree_add_boolean(opensafety_tree, hf_oss_scm_udid_valid, message_tvb, 0, 0, packet->scm_udid_valid);
        if ( udidLen != 6 )
            expert_add_info(pinfo, item, &ei_scmudid_invalid_preference );
        proto_item_set_generated(item);

        if ( packet->msg_type == OPENSAFETY_SSDO_MESSAGE_TYPE || packet->msg_type == OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE )
        {
            proto_item_append_text(opensafety_item,
                    (packet->msg_type == OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE) ? ", Slim SSDO" : ", SSDO");
            dissect_opensafety_ssdo_message ( message_tvb, pinfo, opensafety_tree, packet, opensafety_item );
        }
        else if ( packet->msg_type == OPENSAFETY_SPDO_MESSAGE_TYPE )
        {
            proto_item_append_text(opensafety_item, ", SPDO" );
            dissect_opensafety_spdo_message ( message_tvb, pinfo, opensafety_tree, packet, opensafety_item );

            /* Now we know packet->sender, therefore we can add the info text */
            if ( previous_msg_id != packet->msg_id )
            {
                col_append_fstr(pinfo->cinfo, COL_INFO, (u_nrInPackage > 1 ? " | %s - 0x%03X" : "%s - 0x%03X" ),
                            val_to_str(packet->msg_id, opensafety_message_type_values, "Unknown Message (0x%02X) "),
                            packet->sender );
            } else {
                col_append_fstr(pinfo->cinfo, COL_INFO, ", 0x%03X", packet->sender );
            }
        }
        else
        {
            messageTypeUnknown = TRUE;
            proto_item_append_text(opensafety_item, ", Unknown" );
        }
    }

    crcValid = FALSE;
    item = proto_tree_add_uint(opensafety_tree, hf_oss_length,
                               message_tvb, OSS_FRAME_POS_LEN + packet->frame.subframe1, 1,
                               OSS_FRAME_LENGTH_T(message_tvb, packet->frame.subframe1));
    if ( messageTypeUnknown )
    {
        expert_add_info(pinfo, item, &ei_message_unknown_type );
    }
    else
    {
        crcValid = dissect_opensafety_checksum ( message_tvb, pinfo, opensafety_tree, packet );
    }

    /* with SNMT's we can check if the ID's for the frames match. Rare randomized packages do have
     * an issue, where an frame 1 can be valid. The id's for both frames must differ, as well as
     * the addresses, but addresses won't be checked yet, as there are issues with SDN xored on it. */
    if ( crcValid && packet->msg_type == OPENSAFETY_SNMT_MESSAGE_TYPE )
    {
        if ( OSS_FRAME_ID_T(message_tvb, packet->frame.subframe1) != OSS_FRAME_ID_T(message_tvb, packet->frame.subframe2) )
            expert_add_info(pinfo, opensafety_item, &ei_crc_frame_1_valid_frame2_invalid );
    }

    return TRUE;
}

static const char* opensafety_conv_get_filter_type(conv_item_t* conv, conv_filter_type_e filter)
{
    if (filter == CONV_FT_SRC_ADDRESS) {
        if (conv->src_address.type == AT_NUMERIC)
            return "opensafety.msg.sender";
    }

    if (filter == CONV_FT_DST_ADDRESS) {
        if (conv->dst_address.type == AT_NUMERIC)
            return "opensafety.msg.receiver";
    }

    if (filter == CONV_FT_ANY_ADDRESS) {
        if (conv->src_address.type == AT_NUMERIC && conv->dst_address.type == AT_NUMERIC)
            return "opensafety.msg.node";
    }

    return CONV_FILTER_INVALID;
}

static ct_dissector_info_t opensafety_ct_dissector_info = {&opensafety_conv_get_filter_type};

static const char* opensafety_get_filter_type(endpoint_item_t* endpoint, conv_filter_type_e filter)
{
    if (endpoint->myaddress.type == AT_NUMERIC) {
        if (filter == CONV_FT_ANY_ADDRESS)
            return "opensafety.msg.node";
        else if (filter == CONV_FT_SRC_ADDRESS)
            return "opensafety.msg.sender";
        else if (filter == CONV_FT_DST_ADDRESS)
            return "opensafety.msg.receiver";
    }

    return CONV_FILTER_INVALID;
}

static et_dissector_info_t  opensafety_dissector_info = {&opensafety_get_filter_type};

static tap_packet_status
opensafety_conversation_packet(void *pct, packet_info *pinfo,
        epan_dissect_t *edt _U_, const void *vip, tap_flags_t flags)
{
    address *src = wmem_new0(pinfo->pool, address);
    address *dst = wmem_new0(pinfo->pool, address);
    conv_hash_t *hash = (conv_hash_t*) pct;
    const opensafety_packet_info *osinfo = (const opensafety_packet_info *)vip;
    guint16 receiver = GUINT16_FROM_LE(osinfo->receiver);
    if (osinfo->msg_type == OPENSAFETY_SPDO_MESSAGE_TYPE)
        receiver = OSS_BROADCAST_ADDRESS;
    guint16 sender = GUINT16_FROM_LE(osinfo->sender);

    hash->flags = flags;

    alloc_address_wmem(pinfo->pool, src, AT_NUMERIC, (int) sizeof(guint16), &sender);
    alloc_address_wmem(pinfo->pool, dst, AT_NUMERIC, (int) sizeof(guint16), &receiver);

    add_conversation_table_data(hash, src, dst, 0, 0, 1, osinfo->msg_len, &pinfo->rel_ts, &pinfo->abs_ts,
            &opensafety_ct_dissector_info, CONVERSATION_NONE);

    return TAP_PACKET_REDRAW;
}

static tap_packet_status
opensafety_endpoint_packet(void *pit, packet_info *pinfo,
        epan_dissect_t *edt _U_, const void *vip, tap_flags_t flags)
{
    address *src = wmem_new0(pinfo->pool, address);
    address *dst = wmem_new0(pinfo->pool, address);
    conv_hash_t *hash = (conv_hash_t*) pit;
    const opensafety_packet_info *osinfo = (const opensafety_packet_info *)vip;
    guint16 receiver = GUINT16_FROM_LE(osinfo->receiver);
    if (osinfo->msg_type == OPENSAFETY_SPDO_MESSAGE_TYPE)
        receiver = OSS_BROADCAST_ADDRESS;
    guint16 sender = GUINT16_FROM_LE(osinfo->sender);

    hash->flags = flags;

    alloc_address_wmem(pinfo->pool, src, AT_NUMERIC, (int) sizeof(guint16), &sender);
    alloc_address_wmem(pinfo->pool, dst, AT_NUMERIC, (int) sizeof(guint16), &receiver);

    add_endpoint_table_data(hash, src, 0, TRUE,  1, osinfo->msg_len, &opensafety_dissector_info, ENDPOINT_NONE);
    add_endpoint_table_data(hash, dst, 0, FALSE, 1, osinfo->msg_len, &opensafety_dissector_info, ENDPOINT_NONE);

    return TAP_PACKET_REDRAW;
}

static gboolean
opensafety_package_dissector(const gchar *protocolName, const gchar *sub_diss_handle,
                             gboolean b_frame2First, gboolean do_byte_swap, guint8 force_nr_in_package,
                             tvbuff_t *given_tvb, packet_info *pinfo, proto_tree *tree, guint8 transporttype )
{
    tvbuff_t           *next_tvb = NULL, *gap_tvb = NULL, *message_tvb = NULL;
    guint               length, len, frameOffset, frameLength, nodeAddress, gapStart;
    guint8             *swbytes;
    gboolean            handled, dissectorCalled, call_sub_dissector, markAsMalformed;
    guint8              type, found, i, tempByte, previous_msg_id;
    guint16             frameStart1, frameStart2, byte_offset;
    gint                reported_len;
    dissector_handle_t  protocol_dissector = NULL;
    proto_item         *opensafety_item;
    proto_tree         *opensafety_tree;

    opensafety_packet_info *packet = NULL;

    handled            = FALSE;
    dissectorCalled    = FALSE;
    call_sub_dissector = FALSE;
    markAsMalformed    = FALSE;
    previous_msg_id    = 0;

    /* registering frame end routine, to prevent a malformed dissection preventing
     * further dissector calls (see bug #6950) */
    register_frame_end_routine(pinfo, reset_dissector);

    length = tvb_reported_length(given_tvb);
    /* Minimum package length is 11 */
    if ( length < OSS_MINIMUM_LENGTH )
        return FALSE;

    /* Determine dissector handle for sub-dissection */
    if ( strlen( sub_diss_handle ) > 0 )
    {
        call_sub_dissector = TRUE;
        protocol_dissector = find_dissector ( sub_diss_handle );
        if ( protocol_dissector == NULL )
            protocol_dissector = data_dissector;
    }

    reported_len = tvb_reported_length_remaining(given_tvb, 0);

    /* This will swap the bytes according to MBTCP encoding */
    if ( do_byte_swap == TRUE && global_mbtcp_big_endian == TRUE )
    {
        /* Because of padding bytes at the end of the frame, tvb_memdup could lead
         * to a "openSAFETY truncated" message. By ensuring, that we have enough
         * bytes to copy, this will be prevented. */
        if ( ! tvb_bytes_exist ( given_tvb, 0, length ) )
            return FALSE;

        swbytes = (guint8 *) tvb_memdup( pinfo->pool, given_tvb, 0, length);

        /* Wordswapping for modbus detection */
        /* Only a even number of bytes can be swapped */
        len = (length / 2);
        for ( i = 0; i < len; i++ )
        {
            tempByte = swbytes [ 2 * i ]; swbytes [ 2 * i ] = swbytes [ 2 * i + 1 ]; swbytes [ 2 * i + 1 ] = tempByte;
        }

        message_tvb = tvb_new_real_data(swbytes, length, reported_len);
    } else {
        message_tvb = given_tvb;
    }

    frameOffset = 0;
    frameLength = 0;
    found = 0;

    /* Counter to determine gaps between openSAFETY packages */
    gapStart = 0;

    while ( frameOffset < length )
    {
        /* Reset the next_tvb buffer */
        next_tvb = NULL;

        /* Smallest possible frame size is 11, but this check must ensure, that even the last frame
         * will get considered, which leads us with 10, as the first byte checked is the second one */
        if ( tvb_captured_length_remaining(message_tvb, frameOffset ) < ( OSS_MINIMUM_LENGTH - 1 ) )
            break;

        /* Resetting packet, to ensure, that findSafetyFrame starts with a fresh frame.
         * As only packet_scope is used, this will not polute memory too much and get's
         * cleared with the next packet anyway  */
        packet = wmem_new0(pinfo->pool, opensafety_packet_info);

        /* Finding the start of the first possible safety frame */
        if ( findSafetyFrame(pinfo, message_tvb, frameOffset, b_frame2First, &frameOffset, &frameLength, packet) )
        {
            /* if packet msg_id is not null, it still might be an incorrect frame, as there is no validity
             * check in findSafetyFrame for the msg id (this happens later in this routine)
             * frameLength is calculated/read directly from the dissected data. If frameLength and frameOffset together
             * are bigger than the reported length, the package is not really an openSAFETY package */
            if ( packet->msg_id == 0 || ( frameOffset + frameLength ) > (guint)reported_len )
                break;

            found++;

            byte_offset = ( b_frame2First ? 0 : frameOffset );
            /* We determine a possible position for frame 1 and frame 2 */
            if ( b_frame2First )
            {
                frameStart1 = findFrame1Position (pinfo, message_tvb, byte_offset, frameLength, FALSE );
                frameStart2 = 0;
            }
            else
            {
                frameStart1 = 0;
                frameStart2 = ((OSS_FRAME_LENGTH_T(message_tvb, byte_offset + frameStart1) - 1) +
                        (OSS_FRAME_LENGTH_T(message_tvb, byte_offset + frameStart1) > OSS_PAYLOAD_MAXSIZE_FOR_CRC8 ? OSS_SLIM_FRAME2_WITH_CRC16 : OSS_SLIM_FRAME2_WITH_CRC8));
            }

            /* If both frame starts are equal, something went wrong. In which case, we retract the found entry, and
             * also increase the search offset, just doing a continue will result in an infinite loop. */
            if (frameStart1 == frameStart2)
            {
                found--;
                frameOffset += frameLength;
                continue;
            }

            /* We determine the possible type, and return false, if there could not be one */
            packet->msg_id = OSS_FRAME_ID_T(message_tvb, byte_offset + frameStart1);
            if ( ( packet->msg_id & OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE ) == OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE )
                type = OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE;
            else if ( ( packet->msg_id & OPENSAFETY_SSDO_MESSAGE_TYPE ) == OPENSAFETY_SSDO_MESSAGE_TYPE )
                type = OPENSAFETY_SSDO_MESSAGE_TYPE;
            else if ( ( packet->msg_id & OPENSAFETY_SPDO_MESSAGE_TYPE ) == OPENSAFETY_SPDO_MESSAGE_TYPE )
                type = OPENSAFETY_SPDO_MESSAGE_TYPE;
            else if ( ( packet->msg_id & OPENSAFETY_SNMT_MESSAGE_TYPE ) == OPENSAFETY_SNMT_MESSAGE_TYPE )
                type = OPENSAFETY_SNMT_MESSAGE_TYPE;
            else
            {
                /* This is an invalid openSAFETY package, but it could be an undetected slim ssdo message. This specific error
                 * will only occur, if findFrame1Position is in play. So we search once more, but this time calculating the CRC.
                 * The reason for the second run is, that calculating the CRC is time consuming.  */
                if ( b_frame2First )
                {
                    /* Now let's check again, but this time calculate the CRC */
                    frameStart1 = findFrame1Position(pinfo, message_tvb, ( b_frame2First ? 0 : frameOffset ), frameLength, TRUE );
                    frameStart2 = 0;

                    packet->msg_id = OSS_FRAME_ID_T(message_tvb, byte_offset + frameStart1);
                    if ( ( packet->msg_id & OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE ) == OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE )
                        type = OPENSAFETY_SLIM_SSDO_MESSAGE_TYPE;
                    else if ( ( packet->msg_id & OPENSAFETY_SSDO_MESSAGE_TYPE ) == OPENSAFETY_SSDO_MESSAGE_TYPE )
                        type = OPENSAFETY_SSDO_MESSAGE_TYPE;
                    else if ( ( packet->msg_id & OPENSAFETY_SPDO_MESSAGE_TYPE ) == OPENSAFETY_SPDO_MESSAGE_TYPE )
                        type = OPENSAFETY_SPDO_MESSAGE_TYPE;
                    else if ( ( packet->msg_id & OPENSAFETY_SNMT_MESSAGE_TYPE ) == OPENSAFETY_SNMT_MESSAGE_TYPE )
                        type = OPENSAFETY_SNMT_MESSAGE_TYPE;
                    else {
                        /* Skip this frame.  We cannot continue without
                           advancing frameOffset - just doing a continue
                           will result in an infinite loop. Advancing with 1 will
                           lead to infinite loop, advancing with frameLength might miss
                           some packages*/
                        frameOffset += 2;
                        found--;
                        continue;
                    }
                } else {
                    /* As stated above, you cannot just continue
                       without advancing frameOffset. Advancing with 1 will
                       lead to infinite loop, advancing with frameLength might miss
                       some packages*/
                    frameOffset += 2;
                    found--;
                    continue;
                }
            }

            /* Sorting messages for transporttype */
            if ( global_classify_transport && transporttype != OPENSAFETY_ANY_TRANSPORT )
            {
                /* Cyclic data is transported via SPDOs and acyclic is transported via SNMT, SSDO. Everything
                 * else is misclassification */
                if ( ( transporttype == OPENSAFETY_ACYCLIC_DATA && type == OPENSAFETY_SPDO_MESSAGE_TYPE ) ||
                        ( transporttype == OPENSAFETY_CYCLIC_DATA && type != OPENSAFETY_SPDO_MESSAGE_TYPE ) )
                {
                    frameOffset += 2;
                    found--;
                    continue;
                }
            }

            /* Some faulty packages do indeed have a valid first frame, but the second is
             * invalid. These checks should prevent most faulty detections */
            if ( type != OPENSAFETY_SPDO_MESSAGE_TYPE )
            {
                /* Is the given type at least known? */
                gint idx = -1;
                try_val_to_str_idx(OSS_FRAME_ID_T(message_tvb, byte_offset + frameStart1), opensafety_message_type_values, &idx );
                /* Unknown Frame Type */
                if ( idx < 0 )
                {
                    frameOffset += 2;
                    found--;
                    continue;
                }
                /* Frame IDs do not match */
                else if ( type == OPENSAFETY_SNMT_MESSAGE_TYPE &&
                        (OSS_FRAME_ID_T(message_tvb, byte_offset + frameStart1) != OSS_FRAME_ID_T(message_tvb, byte_offset + frameStart2)) )
                {
                    frameOffset += 2;
                    found--;
                    continue;
                }
            }

            /* If this package is not valid, the next step, which normally occurs in unxorFrame will lead to a
             * frameLength bigger than the maximum data size. This is an indicator, that the package in general
             * is fault, and therefore we return false. Increasing the frameOffset will lead to out-of-bounds
             * for tvb_* functions. And frameLength errors are misidentified packages most of the times anyway */
            if ( ( (gint)frameLength - (gint)( frameStart2 > frameStart1 ? frameStart2 : frameLength - frameStart1 ) ) < 0 )
                return FALSE;

            /* Some SPDO based sanity checks, still a lot of faulty SPDOs remain, because they
             * cannot be filtered, without throwing out too many positives. */
            if ( type == OPENSAFETY_SPDO_MESSAGE_TYPE )
            {
                /* Checking if there is a node address set, or the package is invalid. Some PRes
                 * messages in EPL may double as valid subframes 1. If the nodeAddress is out of
                 * range, the package is marked as malformed */
                nodeAddress = OSS_FRAME_ADDR_T(message_tvb, byte_offset + frameStart1);
                if ( nodeAddress == 0 || nodeAddress > 1024 ) {
                    markAsMalformed = TRUE;
                }

                /* SPDO Reserved is invalid, therefore all packages using this ID can be discarded */
                if ( OSS_FRAME_ID_T(message_tvb, byte_offset + frameStart1) == OPENSAFETY_MSG_SPDO_RESERVED )
                {
                    frameOffset += 2;
                    found--;
                    continue;
                }
            }

            /* Filter node list */
            gint addr = OSS_FRAME_ADDR_T(message_tvb, byte_offset + frameStart1);
            if ( global_filter_list && wmem_list_count ( global_filter_list ) > 0 )
            {
                gboolean found_in_list = wmem_list_find(global_filter_list, GINT_TO_POINTER( addr )) ? TRUE : FALSE;

                if ( ( ! global_show_only_node_in_filter && found_in_list ) ||
                        ( global_show_only_node_in_filter && ! found_in_list ) )
                {
                    opensafety_item = proto_tree_add_item(tree, proto_opensafety, message_tvb, frameOffset, frameLength, ENC_NA);
                    proto_item_append_text(opensafety_item, ", Filtered Node: 0x%03X (%d)", addr, addr);
                    frameOffset += 2;
                    found--;
                    continue;
                }
            }

            /* From here on, the package should be correct. Even if it is not correct, it will be dissected
             * anyway and marked as malformed. Therefore it can be assumed, that a gap will end here.
             */
            if ( global_display_intergap_data == TRUE && gapStart != frameOffset )
            {
                /* Storing the gap data in subset, and calling the data dissector to display it */
                gap_tvb = tvb_new_subset_length_caplen(message_tvb, gapStart, (frameOffset - gapStart), reported_len);
                call_dissector(data_dissector, gap_tvb, pinfo, tree);
            }
            /* Setting the gap to the next offset */
            gapStart = frameOffset + frameLength;

            /* Adding second data source */
            next_tvb = tvb_new_subset_length_caplen ( message_tvb, frameOffset, frameLength, reported_len );

            /* Adding a visual aid to the dissector tree */
            add_new_data_source(pinfo, next_tvb, "openSAFETY Frame");

            /* A new subtype for package dissection will need to set the actual nr. for the whole dissected package */
            if ( force_nr_in_package > 0 )
            {
                found = force_nr_in_package + 1;
                dissectorCalled = TRUE;
                col_set_str(pinfo->cinfo, COL_PROTOCOL, protocolName);
            }

            if ( ! dissectorCalled )
            {
                if ( call_sub_dissector )
                    call_dissector(protocol_dissector, message_tvb, pinfo, tree);
                dissectorCalled = TRUE;

                col_set_str(pinfo->cinfo, COL_PROTOCOL, protocolName);
                col_clear(pinfo->cinfo, COL_INFO);
            }

            /* if the tree is NULL, we are called for the overview, otherwise for the
               more detailed view of the package */
            if ( tree )
            {
                /* create the opensafety protocol tree */
                opensafety_item = proto_tree_add_item(tree, proto_opensafety, message_tvb, frameOffset, frameLength, ENC_NA);
                opensafety_tree = proto_item_add_subtree(opensafety_item, ett_opensafety);
            } else {
                opensafety_item = NULL;
                opensafety_tree = NULL;
            }

            /* Setting type to packet_info */
            packet->msg_type = type;

            packet->frame.frame_tvb = next_tvb;
            packet->frame.byte_offset = frameOffset + tvb_raw_offset(message_tvb);
            packet->frame.subframe1 = frameStart1;
            packet->frame.subframe2 = frameStart2;
            packet->frame.length = frameLength;
            packet->frame.malformed = FALSE;

            /* Clearing connection valid bit */
            if ( packet->msg_type == OPENSAFETY_SPDO_MESSAGE_TYPE )
                packet->msg_id = packet->msg_id & 0xF8;

            if ( dissect_opensafety_message(packet, next_tvb, pinfo, opensafety_item, opensafety_tree, found, previous_msg_id) != TRUE )
                markAsMalformed = TRUE;

            previous_msg_id = packet->msg_id;

            if ( markAsMalformed )
            {
                packet->frame.malformed = TRUE;
                if ( OSS_FRAME_ADDR_T(message_tvb, byte_offset + frameStart1) > 1024 )
                    expert_add_info(pinfo, opensafety_item, &ei_message_spdo_address_invalid );
            }

            tap_queue_packet(opensafety_tap, pinfo, packet);

            /* Something is being displayed, therefore this dissector returns true */
            handled = TRUE;
        }
        else
            break;

        /* findSafetyFrame starts at frameOffset with the search for the next position. But the
         * offset is assumed to be the ID, which can lead to scenarios, where the CRC of a previous
         * detected frame is assumed to be the addr of the next one. +1 prevents such a scenario.
         * It must be checked, if the resulting frameOffset does not scratch the max length. It
         * cannot exceed by adding just frameLength, as this value is a result of the heuristic, and
         * therefore must be within the correct length, but it can exceed if +1 is added unchecked. */
        frameOffset += frameLength;
        if ( tvb_captured_length_remaining(message_tvb, frameOffset) > 0 )
            frameOffset += 1;
    }

    if ( handled == TRUE )
    {
        /* There might be some undissected data at the end of the frame (e.g. SercosIII) */
        if ( frameOffset < length && global_display_intergap_data == TRUE && gapStart != frameOffset )
        {
            /* Storing the gap data in subset, and calling the data dissector to display it */
            gap_tvb = tvb_new_subset_length_caplen(message_tvb, gapStart, (length - gapStart), reported_len);
            call_dissector(data_dissector, gap_tvb, pinfo, tree);
        }
    }

    return ( handled ? TRUE : FALSE );
}

static gboolean
dissect_opensafety_epl(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tree, void *data )
{
    gboolean        result     = FALSE;
    proto_tree      *epl_tree = NULL;
    guint8  epl_msgtype = 0;

    /* We will call the epl dissector by using call_dissector(). The epl dissector will then call
     * the heuristic openSAFETY dissector again. By setting this information, we prevent a dissector
     * loop */
    if ( bDissector_Called_Once_Before == FALSE )
    {
        bDissector_Called_Once_Before = TRUE;

        /* Set the tree up, until it is par with the top-level */
        epl_tree = tree;
        while ( epl_tree != NULL && epl_tree->parent != NULL )
            epl_tree = epl_tree->parent;

        /* Ordering message type to traffic types */
        if ( *((guint8*)data) == 0x03 || *((guint8*)data) == 0x04 )
            epl_msgtype = OPENSAFETY_CYCLIC_DATA;
        else
            epl_msgtype = OPENSAFETY_ACYCLIC_DATA;

        /* We check if we have a asynchronous message, or a synchronous message. In case of
         * asynchronous messages, SPDO packages are not valid. */

        result = opensafety_package_dissector("openSAFETY/Powerlink", "",
                FALSE, FALSE, 0, message_tvb, pinfo, epl_tree, epl_msgtype );

        bDissector_Called_Once_Before = FALSE;
    }

    return result;
}

static gboolean
dissect_opensafety_siii(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tree, void *data _U_ )
{
    gboolean        result     = FALSE;
    gboolean        udp        = FALSE;
    guint8          firstByte;

    /* The UDP dissection is not done by a heuristic, but rather by a normal dissector. But
     * the customer may not expect, that if (s)he disables the SercosIII dissector, that the
     * SercosIII UDP packages get still dissected. This will disable them as well. */
    if ( ! heuristic_siii_dissection_enabled )
        return FALSE;

    /* We will call the SercosIII dissector by using call_dissector(). The SercosIII dissector will
     * then call the heuristic openSAFETY dissector again. By setting this information, we prevent
     * a dissector loop. */
    if ( bDissector_Called_Once_Before == FALSE )
    {
        udp = pinfo->destport == OPENSAFETY_UDP_PORT_SIII;

        bDissector_Called_Once_Before = TRUE;
        /* No frames can be sent in AT messages, therefore those get filtered right away */
        firstByte = ( tvb_get_guint8(message_tvb, 0) << 1 );
        if ( udp || ( firstByte & 0x40 ) == 0x40 )
        {
            result = opensafety_package_dissector( "openSAFETY/SercosIII",
                    udp ? "" : "sercosiii",
                    FALSE, FALSE, 0, message_tvb, pinfo, tree,
                    udp ? OPENSAFETY_ACYCLIC_DATA : OPENSAFETY_CYCLIC_DATA );
        }
        bDissector_Called_Once_Before = FALSE;
    }

    return result;
}

static gboolean
dissect_opensafety_pn_io(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tree, void *data _U_ )
{
    gboolean        result     = FALSE;

    /* We will call the pn_io dissector by using call_dissector(). The epl dissector will then call
     * the heuristic openSAFETY dissector again. By setting this information, we prevent a dissector
     * loop */
    if ( bDissector_Called_Once_Before == FALSE )
    {
        bDissector_Called_Once_Before = TRUE;
        result = opensafety_package_dissector("openSAFETY/Profinet IO", "pn_io",
                                              FALSE, FALSE, 0, message_tvb, pinfo, tree, OPENSAFETY_ANY_TRANSPORT);
        bDissector_Called_Once_Before = FALSE;
    }

    return result;
}

static gboolean
dissect_opensafety_mbtcp(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tree, void *data _U_ )
{
    if ( ! global_enable_mbtcp )
        return FALSE;

    /* When Modbus/TCP gets dissected, openSAFETY would be sorted as a child protocol. Although,
     * this behaviour is technically correct, it differs from other implemented IEM protocol handlers.
     * Therefore, the openSAFETY frame gets put one up, if the parent is not NULL */
    return opensafety_package_dissector("openSAFETY/Modbus TCP", "", FALSE, TRUE, 0,
                                        message_tvb, pinfo, ( ((tree != NULL) && (tree->parent != NULL)) ? tree->parent : tree ),
                                        OPENSAFETY_ANY_TRANSPORT);
}

static gboolean
opensafety_udp_transport_dissector(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tree)
{
    proto_item      *ti = NULL;
    proto_tree      *transport_tree = NULL;
    gint            offset = 0;
    tvbuff_t        *os_tvb = 0;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "openSAFETY over UDP");
    col_clear(pinfo->cinfo, COL_INFO);

    ti = proto_tree_add_item(tree, proto_oss_udp_transport, message_tvb, 0, -1, ENC_NA);
    transport_tree = proto_item_add_subtree(ti, ett_opensafety);

    proto_tree_add_item(transport_tree, hf_oss_udp_transport_version, message_tvb, 0, 1, ENC_BIG_ENDIAN);
    proto_tree_add_item(transport_tree, hf_oss_udp_transport_flags_type, message_tvb, 1, 1, ENC_BIG_ENDIAN);
    proto_tree_add_item(transport_tree, hf_oss_udp_transport_counter, message_tvb, 2, 2, ENC_LITTLE_ENDIAN);

    proto_tree_add_item(transport_tree, hf_oss_udp_transport_sender, message_tvb, 4, 4, ENC_LITTLE_ENDIAN);
    proto_tree_add_item(transport_tree, hf_oss_udp_transport_datapoint, message_tvb, 8, 2, ENC_LITTLE_ENDIAN);
    proto_tree_add_item(transport_tree, hf_oss_udp_transport_length, message_tvb, 10, 2, ENC_LITTLE_ENDIAN);
    offset += 12;

    os_tvb = tvb_new_subset_remaining(message_tvb, offset);

    if ( ! opensafety_package_dissector("openSAFETY/UDP", "", FALSE,
            FALSE, 0, os_tvb, pinfo, tree, OPENSAFETY_ANY_TRANSPORT ) )
        call_dissector(find_dissector("data"), os_tvb, pinfo, transport_tree);

    return TRUE;
}

static gboolean
dissect_opensafety_udpdata(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tree, void *data _U_ )
{
    gboolean       result   = FALSE;
    static guint32 frameNum = 0;
    static guint32 frameIdx = 0;

    gboolean frameFound = FALSE;
    guint    frameOffset = 0;
    guint    frameLength = 0;

    if ( pinfo->destport == OPENSAFETY_UDP_PORT_SIII )
        return dissect_opensafety_siii(message_tvb, pinfo, tree, data);

    if ( ! global_enable_udp )
        return result;

    /* An openSAFETY frame has at least OSS_MINIMUM_LENGTH bytes */
    if ( tvb_captured_length ( message_tvb ) < OSS_MINIMUM_LENGTH )
        return result;

    /* More than one openSAFETY package could be transported in the same frame,
     * in such a case, we need to establish the number of packages inside the frame */
    if ( pinfo->num != frameNum )
    {
        frameIdx = 0;
        frameNum = pinfo->num;
    }

    /* check for openSAFETY frame at beginning of data */

    frameFound = findSafetyFrame(pinfo, message_tvb, 0, global_udp_frame2_first, &frameOffset, &frameLength, NULL );
    if ( ! frameFound || ( frameOffset >= 11 ) )
    {
        dissector_handle_t udp_transport = find_dissector ( "opensafety_udp_transport" );
        if ( udp_transport != NULL )
            call_dissector(udp_transport, message_tvb, pinfo, tree);
        result = opensafety_udp_transport_dissector(message_tvb, pinfo, tree);
    }
    else
        result = opensafety_package_dissector("openSAFETY/UDP", "", global_udp_frame2_first,
                                          FALSE, frameIdx, message_tvb, pinfo, tree, OPENSAFETY_ACYCLIC_DATA );

    if ( result )
        frameIdx++;

    return result;
}

static void
apply_prefs ( void )
{
    static guint    opensafety_udp_port_number;
    static guint    opensafety_udp_siii_port_number;
    static gboolean opensafety_init = FALSE;

    /* It only should delete dissectors, if run for any time except the first */
    if ( opensafety_init )
    {
        /* Delete dissectors in preparation of a changed config setting */
        dissector_delete_uint ("udp.port", opensafety_udp_port_number, opensafety_udptransport_handle);
        dissector_delete_uint ("udp.port", opensafety_udp_siii_port_number, opensafety_udpdata_handle);
    }
    opensafety_init = TRUE;

    /* Storing the port numbers locally, to being able to delete the old associations */
    opensafety_udp_port_number = global_network_udp_port;
    opensafety_udp_siii_port_number = global_network_udp_port_sercosiii;

    /* Default UDP only based dissector, will hand traffic to SIII dissector if needed */
    /* Preference names to specific to use "auto" preference */
    dissector_add_uint("udp.port", opensafety_udp_port_number, opensafety_udptransport_handle);
    dissector_add_uint("udp.port", opensafety_udp_siii_port_number, opensafety_udpdata_handle);
}

void
proto_register_opensafety(void)
{
    /* Setup list of header fields */
    static hf_register_info hf[] = {
        { &hf_oss_scm_udid,
          { "SCM UDID Configured",    "opensafety.scm_udid",
            FT_STRING,   BASE_NONE, NULL,   0x0, NULL, HFILL } },
        { &hf_oss_scm_udid_auto,
          { "SCM UDID Auto Detect",    "opensafety.scm_udid.auto",
            FT_STRING,   BASE_NONE, NULL,   0x0, NULL, HFILL } },
        { &hf_oss_scm_udid_valid,
          { "SCM UDID Valid",    "opensafety.scm_udid.valid",
            FT_BOOLEAN,   BASE_NONE, NULL,   0x0, NULL, HFILL } },

        { &hf_oss_byte_offset,
          { "Byte Offset",    "opensafety.msg.byte_offset",
            FT_UINT16,  BASE_HEX, NULL,   0x0, NULL, HFILL } },
        { &hf_oss_msg,
          { "Message",    "opensafety.msg.id",
            FT_UINT8,   BASE_HEX, VALS(opensafety_message_type_values),   0x0, NULL, HFILL } },
        { &hf_oss_msg_category,
          { "Type",  "opensafety.msg.type",
            FT_UINT8,   BASE_HEX, VALS(opensafety_msg_id_values),   0xE0, NULL, HFILL } },
        { &hf_oss_msg_direction,
          { "Direction",  "opensafety.msg.direction",
            FT_BOOLEAN,   8, TFS(&opensafety_message_direction),   0x04, NULL, HFILL } },
        { &hf_oss_msg_node,
          { "Safety Node",  "opensafety.msg.node",
            FT_UINT16,   BASE_HEX, NULL,   0x0, NULL, HFILL } },
        { &hf_oss_msg_network,
          { "Safety Domain",  "opensafety.msg.network",
            FT_UINT16,   BASE_HEX, NULL,   0x0, NULL, HFILL } },
        { &hf_oss_msg_sender,
          { "SN send from",  "opensafety.msg.sender",
            FT_UINT16,   BASE_HEX, NULL,   0x0, NULL, HFILL } },
        { &hf_oss_msg_receiver,
          { "SN send to",  "opensafety.msg.receiver",
            FT_UINT16,   BASE_HEX, NULL,   0x0, NULL, HFILL } },
        { &hf_oss_length,
          { "Length",    "opensafety.length",
            FT_UINT8,   BASE_DEC, NULL,     0x0, NULL, HFILL } },
        { &hf_oss_crc,
          { "CRC",       "opensafety.crc.data",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },

        { &hf_oss_crc_valid,
          { "Is Valid", "opensafety.crc.valid",
            FT_BOOLEAN, BASE_NONE, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_crc_type,
          { "CRC Type",  "opensafety.crc.type",
            FT_UINT8,   BASE_DEC, VALS(opensafety_frame_crc_type),    0x0, NULL, HFILL } },
        { &hf_oss_crc2_valid,
          { "Is Valid", "opensafety.crc2.valid",
            FT_BOOLEAN, BASE_NONE, NULL,    0x0, NULL, HFILL } },

        /* SNMT Specific fields */
        { &hf_oss_snmt_slave,
          { "SNMT Slave",    "opensafety.snmt.slave",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_snmt_master,
          { "SNMT Master",   "opensafety.snmt.master",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_snmt_scm,
          { "SCM",    "opensafety.snmt.scm",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_snmt_tool,
          { "Tool ID",   "opensafety.snmt.tool_id",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_snmt_udid,
          { "UDID for SN",   "opensafety.snmt.udid",
            FT_ETHER,  BASE_NONE, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_snmt_service_id,
          { "Extended Service ID",   "opensafety.snmt.service_id",
            FT_UINT8,  BASE_HEX, VALS(opensafety_message_service_type),    0x0, NULL, HFILL } },
        { &hf_oss_snmt_error_group,
          { "Error Group",   "opensafety.snmt.error_group",
            FT_UINT8,  BASE_DEC, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_snmt_error_code,
          { "Error Code",   "opensafety.snmt.error_code",
            FT_UINT8,  BASE_DEC, NULL,   0x0, NULL, HFILL } },
        { &hf_oss_snmt_param_type,
          { "Parameter Request Type",   "opensafety.snmt.parameter_type",
            FT_BOOLEAN,  BASE_NONE, TFS(&opensafety_addparam_request),   0x0, NULL, HFILL } },
        { &hf_oss_snmt_ext_addsaddr,
          { "Additional SADDR",    "opensafety.snmt.additional.saddr",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_snmt_ext_addtxspdo,
          { "Additional TxSPDO",    "opensafety.snmt.additional.txspdo",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_snmt_ext_initct,
          { "Initial CT", "opensafety.snmt.initct",
            FT_UINT40,  BASE_HEX, NULL,    0x0, NULL, HFILL } },

        /* SSDO Specific fields */
        { &hf_oss_ssdo_server,
          { "SSDO Server", "opensafety.ssdo.master",
            FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_client,
          { "SSDO Client", "opensafety.ssdo.client",
            FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_sano,
          { "SOD Access Request Number", "opensafety.ssdo.sano",
            FT_UINT16,  BASE_DEC, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_ssdo_sacmd,
          { "SOD Access Command", "opensafety.ssdo.sacmd",
            FT_UINT8,  BASE_HEX, VALS(opensafety_ssdo_sacmd_values),    0x0, NULL, HFILL } },
        { &hf_oss_ssdo_sod_index,
          { "SOD Index", "opensafety.ssdo.sodentry.index",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_ssdo_sod_subindex,
          { "SOD Sub Index", "opensafety.ssdo.sodentry.subindex",
            FT_UINT8,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_ssdo_payload,
          { "SOD Payload", "opensafety.ssdo.payload",
            FT_BYTES,  BASE_NONE, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_ssdo_payload_size,
          { "SOD Payload Size", "opensafety.ssdo.payloadsize",
            FT_UINT32,  BASE_DEC, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_ssdo_sodentry_size,
          { "SOD Entry Size", "opensafety.ssdo.sodentry.size",
            FT_UINT32,  BASE_DEC, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_ssdo_sodentry_data,
          { "SOD Data", "opensafety.ssdo.sodentry.data",
            FT_BYTES,  BASE_NONE, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_sod_par_timestamp,
          { "Parameter Timestamp", "opensafety.sod.parameter.timestamp",
            FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_sod_par_checksum,
          { "Parameter Checksum", "opensafety.sod.parameter.checksum",
            FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL } },

        { &hf_oss_ssdo_sodmapping,
          { "Mapping entry", "opensafety.sod.mapping",
            FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_sodmapping_bits,
          { "Mapping size", "opensafety.sod.mapping.bits",
            FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } },

        { &hf_oss_ssdo_extpar_parset,
          { "Additional Parameter Set", "opensafety.ssdo.extpar.setnr",
            FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_extpar_version,
          { "Parameter Set Version", "opensafety.ssdo.extpar.version",
            FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_extpar_saddr,
          { "Parameter Set for SADDR", "opensafety.ssdo.extpar.saddr",
            FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_extpar_length,
          { "Parameter Set Length", "opensafety.ssdo.extpar.length",
            FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_extpar_crc,
          { "Parameter Set CRC", "opensafety.ssdo.extpar.crc",
            FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_extpar_tstamp,
          { "Timestamp", "opensafety.ssdo.extpar.timestamp",
            FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_extpar_data,
          { "Ext. Parameter Data", "opensafety.ssdo.extpar.data",
            FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } },
        { &hf_oss_ssdo_extpar,
          { "Ext. Parameter", "opensafety.ssdo.extpar",
            FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } },

        {&hf_oss_fragments,
         {"Message fragments", "opensafety.ssdo.fragments",
          FT_NONE, BASE_NONE, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_fragment,
         {"Message fragment", "opensafety.ssdo.fragment",
          FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_fragment_overlap,
         {"Message fragment overlap", "opensafety.ssdo.fragment.overlap",
          FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_fragment_overlap_conflicts,
         {"Message fragment overlapping with conflicting data",
          "opensafety.ssdo.fragment.overlap.conflicts",
          FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_fragment_multiple_tails,
         {"Message has multiple tail fragments", "opensafety.ssdo.fragment.multiple_tails",
          FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_fragment_too_long_fragment,
         {"Message fragment too long", "opensafety.ssdo.fragment.too_long_fragment",
          FT_BOOLEAN, 0, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_fragment_error,
         {"Message defragmentation error", "opensafety.ssdo.fragment.error",
          FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_fragment_count,
         {"Message fragment count", "opensafety.ssdo.fragment.count",
          FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_reassembled_in,
         {"Reassembled in", "opensafety.ssdo.reassembled.in",
          FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_reassembled_length,
         {"Reassembled length", "opensafety.ssdo.reassembled.length",
          FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL } },
        {&hf_oss_reassembled_data,
         {"Reassembled Data", "opensafety.ssdo.reassembled.data",
          FT_BYTES, BASE_NONE, NULL, 0x00, NULL, HFILL } },

        { &hf_oss_ssdo_abort_code,
          { "Abort Code", "opensafety.ssdo.abortcode",
            FT_UINT32,  BASE_HEX, NULL,    0x0, NULL, HFILL } },

        { &hf_oss_ssdo_preload_error,
          { "Wrong/missing segment", "opensafety.ssdo.preload.error",
            FT_BOOLEAN, 8, NULL,    0x30, NULL, HFILL } },
        { &hf_oss_ssdo_preload_queue,
          { "Preload Queue Size", "opensafety.ssdo.preload.queuesize",
            FT_UINT8,  BASE_DEC, NULL,    0x0, NULL, HFILL } },

        /* SSDO SACmd specific fields */
        { &hf_oss_ssdo_sacmd_access_type,
          { "Access Direction", "opensafety.ssdo.sacmd.access",
            FT_BOOLEAN,  8, TFS(&opensafety_sacmd_acc), OPENSAFETY_SSDO_SACMD_ACC, NULL, HFILL } },
        { &hf_oss_ssdo_sacmd_preload,
          { "Preload Transfer", "opensafety.ssdo.sacmd.preload",
            FT_BOOLEAN,  8, TFS(&tfs_enabled_disabled), OPENSAFETY_SSDO_SACMD_PRLD, NULL, HFILL } },
        { &hf_oss_ssdo_sacmd_abort_transfer,
          { "Abort Transfer", "opensafety.ssdo.sacmd.abort_transfer",
            FT_BOOLEAN,  8, TFS(&opensafety_sacmd_abrt), OPENSAFETY_SSDO_SACMD_ABRT, NULL, HFILL } },
        { &hf_oss_ssdo_sacmd_segmentation,
          { "Segmentation", "opensafety.ssdo.sacmd.segmentation",
            FT_BOOLEAN,  8, TFS(&opensafety_sacmd_seg), OPENSAFETY_SSDO_SACMD_SEG, NULL, HFILL } },
        { &hf_oss_ssdo_sacmd_toggle,
          { "Toggle Bit", "opensafety.ssdo.sacmd.toggle",
            FT_BOOLEAN,  8, TFS(&tfs_on_off), OPENSAFETY_SSDO_SACMD_TGL, NULL, HFILL } },
        { &hf_oss_ssdo_sacmd_initiate,
          { "Initiate Transfer", "opensafety.ssdo.sacmd.initiate",
            FT_BOOLEAN,  8, TFS(&opensafety_sacmd_ini), OPENSAFETY_SSDO_SACMD_INI, NULL, HFILL } },
        { &hf_oss_ssdo_sacmd_end_segment,
          { "End Segment", "opensafety.ssdo.sacmd.end_segment",
            FT_BOOLEAN,  8, TFS(&opensafety_sacmd_ensg), OPENSAFETY_SSDO_SACMD_ENSG, NULL, HFILL } },
#if 0
        { &hf_oss_ssdo_sacmd_reserved,
          { "Reserved", "opensafety.ssdo.sacmd.reserved",
            FT_BOOLEAN,  8, TFS(&opensafety_sacmd_res), OPENSAFETY_SSDO_SACMD_RES, NULL, HFILL } },
#endif

        /* SPDO Specific fields */
        { &hf_oss_spdo_connection_valid,
          { "Connection Valid Bit", "opensafety.spdo.connection_valid",
            FT_BOOLEAN,  8, TFS(&tfs_set_notset),  0x04, NULL, HFILL } },
        { &hf_oss_spdo_direction,
          { "Send to",  "opensafety.spdo.direction",
            FT_BOOLEAN,   8, TFS(&opensafety_spdo_direction),   0x08, NULL, HFILL } },
        { &hf_oss_spdo_ct,
          { "Consecutive Time", "opensafety.spdo.ct",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_spdo_ct_40bit,
          { "Consecutive Time 40bit", "opensafety.spdo.ct40bit",
            FT_UINT40,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_spdo_time_request,
          { "Time Request Counter", "opensafety.spdo.time.request_counter",
            FT_UINT8,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_spdo_time_request_to,
          { "Time Request from", "opensafety.spdo.time.request_from",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_spdo_time_request_from,
          { "Time Request by", "opensafety.spdo.time.request_to",
            FT_UINT16,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_spdo_feature_flags,
          { "SPDO Feature Flags", "opensafety.spdo.featureflags",
            FT_UINT8,  BASE_HEX, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_spdo_feature_flag_40bit_available,
          { "40Bit Request", "opensafety.spdo.features.40bitrequest",
            FT_BOOLEAN,  8, TFS(&tfs_requested_not_requested), (OPENSAFETY_SPDO_FEAT_40BIT_AVAIL << 2), NULL, HFILL } },
        { &hf_oss_spdo_feature_flag_40bit_used,
          { "40Bit Counter", "opensafety.spdo.features.40bitactive",
            FT_BOOLEAN,  8, TFS(&tfs_enabled_disabled), (OPENSAFETY_SPDO_FEAT_40BIT_USED << 2), NULL, HFILL } },
    };

    /* Setup list of header fields */
    static hf_register_info hf_oss_udp_transport[] = {
        /* UDP transport specific fields */
        { &hf_oss_udp_transport_version,
          { "Transport Version", "opensafety.udp_transport.version",
            FT_UINT8,  BASE_DEC, NULL,  0x0, NULL, HFILL } },
        { &hf_oss_udp_transport_flags_type,
          { "Data Type", "opensafety.udp_transport.flags.type",
            FT_BOOLEAN, 8, TFS(&tfs_udp_transport_cyclic_acyclic),  0x01, NULL, HFILL } },
        { &hf_oss_udp_transport_counter,
          { "Counter", "opensafety.udp_transport.counter",
            FT_UINT16,  BASE_HEX_DEC, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_udp_transport_sender,
          { "Sender ID", "opensafety.udp_transport.sender",
            FT_UINT32,  BASE_HEX_DEC, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_udp_transport_datapoint,
          { "Datapoint ID", "opensafety.udp_transport.datapoint",
            FT_UINT16,  BASE_HEX_DEC, NULL,    0x0, NULL, HFILL } },
        { &hf_oss_udp_transport_length,
          { "Length", "opensafety.udp_transport.length",
            FT_UINT16,  BASE_DEC, NULL,    0x0, NULL, HFILL } },

    };

    /* Setup protocol subtree array */
    static gint *ett[] = {
        &ett_opensafety,
        &ett_opensafety_node,
        &ett_opensafety_checksum,
        &ett_opensafety_snmt,
        &ett_opensafety_ssdo,
        &ett_opensafety_ssdo_sacmd,
        &ett_opensafety_ssdo_fragment,
        &ett_opensafety_ssdo_fragments,
        &ett_opensafety_ssdo_payload,
        &ett_opensafety_ssdo_sodentry,
        &ett_opensafety_sod_mapping,
        &ett_opensafety_ssdo_extpar,
        &ett_opensafety_spdo,
        &ett_opensafety_spdo_flags,
    };

    static gint *ett_oss_udp[] = {
        &ett_oss_udp_transport,
    };

    static ei_register_info ei[] = {
        { &ei_crc_frame_1_invalid,
          { "opensafety.crc.error.frame1_invalid", PI_PROTOCOL, PI_ERROR,
            "Frame 1 CRC invalid, Possible error in package", EXPFILL } },
        { &ei_crc_frame_1_valid_frame2_invalid,
          { "opensafety.crc.error.frame1_valid_frame2_invalid", PI_PROTOCOL, PI_ERROR,
            "Frame 1 is valid, frame 2 id is invalid", EXPFILL } },
        { &ei_crc_slimssdo_instead_of_spdo,
          { "opensafety.crc.warning.wrong_crc_for_spdo", PI_PROTOCOL, PI_WARN,
            "Frame 1 SPDO CRC is Slim SSDO CRC16 0x5935", EXPFILL } },
        { &ei_crc_frame_2_invalid,
          { "opensafety.crc.error.frame2_invalid", PI_PROTOCOL, PI_ERROR,
            "Frame 2 CRC invalid, Possible error in package or crc calculation", EXPFILL } },
        { &ei_crc_frame_2_unknown_scm_udid,
          { "opensafety.crc.error.frame2_unknown_scmudid", PI_PROTOCOL, PI_WARN,
            "Frame 2 CRC invalid, SCM UDID was not auto-detected", EXPFILL } },
        { &ei_crc_frame_2_scm_udid_encoded,
          { "opensafety.crc.error.crc2_scm_udid_encoded", PI_PROTOCOL, PI_NOTE,
            "Frame 2 CRC is encoded with byte 6 of SCM UDID due to payload length of 0 in frame 2 or SLIM SSDO", EXPFILL } },

        { &ei_message_reassembly_size_differs_from_header,
          { "opensafety.msg.warning.reassembly_size_fail", PI_PROTOCOL, PI_WARN,
            "Reassembled message size differs from size in header", EXPFILL } },
        { &ei_message_unknown_type,
          { "opensafety.msg.error.unknown_type", PI_MALFORMED, PI_ERROR,
            "Unknown openSAFETY message type", EXPFILL } },
        { &ei_message_spdo_address_invalid,
          { "opensafety.msg.error.spdo_address_invalid", PI_MALFORMED, PI_ERROR,
            "SPDO address is invalid", EXPFILL } },
        { &ei_message_id_field_mismatch,
          { "opensafety.msg.error.id.mismatch", PI_PROTOCOL, PI_ERROR,
            "ID for frame 2 is not the same as for frame 1", EXPFILL } },

        { &ei_scmudid_autodetected,
          { "opensafety.scm_udid.note.autodetected", PI_PROTOCOL, PI_NOTE,
            "Auto detected payload as SCM UDID", EXPFILL } },
        { &ei_scmudid_invalid_preference,
          { "opensafety.scm_udid.note.invalid_preference", PI_PROTOCOL, PI_WARN,
            "openSAFETY protocol settings are invalid! SCM UDID first octet will be assumed to be 00", EXPFILL } },
        { &ei_scmudid_unknown,
          { "opensafety.scm_udid.warning.assuming_first_octet", PI_PROTOCOL, PI_WARN,
            "SCM UDID unknown, assuming 00 as first UDID octet", EXPFILL } },

        { &ei_payload_unknown_format,
          { "opensafety.msg.warning.unknown_format", PI_PROTOCOL, PI_WARN,
            "Unknown payload format detected", EXPFILL } },
        { &ei_payload_length_not_positive,
          { "opensafety.msg.warning.reassembly_length_not_positive", PI_PROTOCOL, PI_NOTE,
            "Calculation for payload length yielded non-positive result", EXPFILL } },

        { &ei_40bit_default_domain,
          { "opensafety.msg.warning.default_domain_40bit", PI_PROTOCOL, PI_NOTE,
            "SDN is assumed with 1 to allow 40bit dissection", EXPFILL } },

    };

    module_t *opensafety_module, *oss_udp_module;
    expert_module_t *expert_opensafety;

    /* Register the protocol name and description */
    proto_opensafety = proto_register_protocol("openSAFETY", "openSAFETY",  "opensafety");
    opensafety_module = prefs_register_protocol(proto_opensafety, apply_prefs);
    proto_oss_udp_transport = proto_register_protocol("openSAFETY over UDP", "openSAFETY ov. UDP", "opensafety_udp");
    oss_udp_module = prefs_register_protocol(proto_oss_udp_transport, apply_prefs);

    /* Register data dissector */
    heur_opensafety_spdo_subdissector_list = register_heur_dissector_list("opensafety.spdo", proto_opensafety);

    /* Required function calls to register the header fields and subtrees used */
    proto_register_field_array(proto_opensafety, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
    proto_register_field_array(proto_oss_udp_transport, hf_oss_udp_transport, array_length(hf_oss_udp_transport));
    proto_register_subtree_array(ett_oss_udp, array_length(ett_oss_udp));

    /* Register tap */
    opensafety_tap = register_tap("opensafety");

    expert_opensafety = expert_register_protocol ( proto_opensafety );
    expert_register_field_array ( expert_opensafety, ei, array_length (ei ) );

    /* register user preferences */
    prefs_register_string_preference(opensafety_module, "scm_udid",
                 "SCM UDID (xx:xx:xx:xx:xx:xx)",
                 "To be able to fully dissect SSDO and SPDO packages, a valid UDID for the SCM has to be provided",
                 &global_scm_udid);
    prefs_register_bool_preference(opensafety_module, "scm_udid_autoset",
                 "Set SCM UDID if detected in stream",
                 "Automatically assign a detected SCM UDID (by reading SNMT->SNTM_assign_UDID_SCM) and set it for the file",
                 &global_scm_udid_autoset);

    prefs_register_string_preference(opensafety_module, "filter_nodes",
                 "Filter openSAFETY Nodes",
                 "A comma-separated list of nodes to be filtered during dissection",
                 &global_filter_nodes);
    prefs_register_bool_preference(opensafety_module, "filter_show_nodes_in_filterlist",
                 "Show nodes in filter, hide otherwise",
                 "If set to true, only nodes in the list will be shown, otherwise they will be hidden",
                 &global_show_only_node_in_filter);

    prefs_register_uint_preference(opensafety_module, "network_udp_port",
                "Port used for Generic UDP",
                "Port used by any UDP demo implementation to transport data", 10,
                &global_network_udp_port);
    prefs_register_uint_preference(opensafety_module, "network_udp_port_sercosiii",
                "Port used for SercosIII/UDP",
                "UDP port used by SercosIII to transport data", 10,
                &global_network_udp_port_sercosiii);
    prefs_register_bool_preference(opensafety_module, "network_udp_frame_first_sercosiii",
                "openSAFETY frame 2 before frame 1 (SercosIII/UDP only)",
                "In an SercosIII/UDP transport stream, openSAFETY frame 2 will be expected before frame 1",
                &global_siii_udp_frame2_first );

    prefs_register_bool_preference(opensafety_module, "network_udp_frame_first",
                "openSAFETY frame 2 before frame 1 (UDP only)",
                "In the transport stream, openSAFETY frame 2 will be expected before frame 1",
                &global_udp_frame2_first );
    prefs_register_bool_preference(opensafety_module, "mbtcp_big_endian",
                "Big Endian Word Coding (Modbus/TCP only)",
                "Modbus/TCP words can be transcoded either big- or little endian. Default will be little endian",
                &global_mbtcp_big_endian);
    prefs_register_bool_preference(opensafety_module, "debug_verbose",
                "openSAFETY print all dissection information",
                "Enables additional information in the dissection for better debugging an openSAFETY trace",
                &global_opensafety_debug_verbose );

    prefs_register_obsolete_preference(opensafety_module, "enable_plk");
    prefs_register_obsolete_preference(opensafety_module, "enable_siii");
    prefs_register_obsolete_preference(opensafety_module, "enable_pnio");

    prefs_register_bool_preference(opensafety_module, "enable_udp",
                "Enable heuristic dissection for openSAFETY over UDP encoded traffic", "Enable heuristic dissection for openSAFETY over UDP encoded traffic",
                &global_enable_udp);
    prefs_register_bool_preference(opensafety_module, "enable_mbtcp",
                "Enable heuristic dissection for Modbus/TCP", "Enable heuristic dissection for Modbus/TCP",
                &global_enable_mbtcp);

    prefs_register_bool_preference(opensafety_module, "display_intergap_data",
                "Display the data between openSAFETY packets", "Display the data between openSAFETY packets",
                &global_display_intergap_data);
    prefs_register_bool_preference(opensafety_module, "classify_transport",
                "Dissect packet based on transport method (EPL + SercosIII only)",
                "SPDOs may only be found in cyclic data, SSDOs/SNMTS only in acyclic data",
                &global_classify_transport);

    prefs_register_uint_preference(oss_udp_module, "network_udp_port",
                "Port used for UDP Transport",
                "Port used by the openSAFETY over UDP data transport", 10,
                &global_network_oss_udp_port);

    /* Registering default and ModBus/TCP dissector */
    opensafety_udpdata_handle = register_dissector("opensafety_udp", dissect_opensafety_udpdata, proto_opensafety );
    opensafety_udptransport_handle =
            register_dissector("opensafety_udptransport", dissect_opensafety_udpdata, proto_oss_udp_transport );
    opensafety_mbtcp_handle = register_dissector("opensafety_mbtcp", dissect_opensafety_mbtcp, proto_opensafety );
    opensafety_pnio_handle = register_dissector("opensafety_pnio", dissect_opensafety_pn_io, proto_opensafety);

    register_conversation_table(proto_opensafety, TRUE, opensafety_conversation_packet, opensafety_endpoint_packet);
}

void
proto_reg_handoff_opensafety(void)
{
    /* Storing global data_dissector */
    data_dissector = find_dissector ( "data" );

    /* EPL & SercosIII dissector registration */
    heur_dissector_add("epl_data",  dissect_opensafety_epl, "openSAFETY over EPL", "opensafety_epl_data", proto_opensafety, HEURISTIC_ENABLE);
    heur_dissector_add("sercosiii", dissect_opensafety_siii, "openSAFETY over SercosIII", "opensafety_sercosiii", proto_opensafety, HEURISTIC_ENABLE);

    /* Modbus TCP dissector registration */
    dissector_add_string("modbus.data", "data", opensafety_mbtcp_handle);

    /* For Profinet we have to register as a heuristic dissector, as Profinet
     *  is implemented as a plugin, and therefore the heuristic dissector is not
     *  added by the time this method is being called
     */
    if ( find_dissector("pn_io") != NULL )
    {
        heur_dissector_add("pn_io", dissect_opensafety_pn_io, "openSAFETY over Profinet", "opensafety_pn_io", proto_opensafety, HEURISTIC_DISABLE);
    }
    else
    {
        /* The native dissector cannot be loaded. so we add our protocol directly to
         * the ethernet subdissector list. No PNIO specific data will be dissected
         * and a warning will be displayed, recognizing the missing dissector plugin.
         */
        dissector_add_uint("ethertype", ETHERTYPE_PROFINET, opensafety_pnio_handle);
    }

    apply_prefs();

    register_init_routine ( setup_dissector );
    register_cleanup_routine ( cleanup_dissector );

    reassembly_table_register(&os_reassembly_table, &addresses_reassembly_table_functions);

    /* registering frame end routine, to prevent a malformed dissection preventing
     * further dissector calls (see bug #6950) */
    /* register_frame_end_routine(reset_dissector); */
}

/*
 * 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:
 */