aboutsummaryrefslogtreecommitdiffstats
path: root/packet-fc.c
blob: 32ff569dcb76c492b9501a2b4c6e18011254bf91 (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
/* packet-fc.c
 * Routines for Fibre Channel Decoding (FC Header, Link Ctl & Basic Link Svc) 
 * Copyright 2001, Dinesh G Dutt <ddutt@cisco.com>
 *   Copyright 2003  Ronnie Sahlberg, exchange first/last matching and 
 *                                    tap listener and misc updates
 *
 * $Id: packet-fc.c,v 1.18 2004/02/19 00:29:15 gerald Exp $
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@ethereal.com>
 * Copyright 1998 Gerald Combs
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"

#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif

#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif

#include <glib.h>

#ifdef NEED_SNPRINTF_H
# include "snprintf.h"
#endif

#include <epan/packet.h>
#include "prefs.h"
#include "reassemble.h"
#include <epan/conversation.h>
#include "etypes.h"
#include "packet-fc.h"
#include "packet-fclctl.h"
#include "packet-fcbls.h"
#include "tap.h"

#define FC_HEADER_SIZE         24
#define FC_RCTL_EISL           0x50
#define MDSHDR_TRAILER_SIZE    6 

/* Size of various fields in FC header in bytes */
#define FC_RCTL_SIZE           1
#define FC_DID_SIZE            3
#define FC_CSCTL_SIZE          1
#define FC_SID_SIZE            3
#define FC_TYPE_SIZE           1
#define FC_FCTL_SIZE           3
#define FC_SEQID_SIZE          1
#define FC_DFCTL_SIZE          1
#define FC_SEQCNT_SIZE         2
#define FC_OXID_SIZE           2
#define FC_RXID_SIZE           2
#define FC_PARAM_SIZE          4

/* Initialize the protocol and registered fields */
static int proto_fc = -1;
static int hf_fc_time = -1;
static int hf_fc_exchange_first_frame = -1;
static int hf_fc_exchange_last_frame = -1;
static int hf_fc_rctl = -1;
static int hf_fc_did = -1;
static int hf_fc_csctl = -1;
static int hf_fc_sid = -1;
static int hf_fc_id = -1;
static int hf_fc_type = -1;
static int hf_fc_fctl = -1;
static int hf_fc_fctl_exchange_responder = -1;
static int hf_fc_fctl_seq_recipient = -1;
static int hf_fc_fctl_exchange_first = -1;
static int hf_fc_fctl_exchange_last = -1;
static int hf_fc_fctl_seq_last = -1;
static int hf_fc_fctl_priority = -1;
static int hf_fc_fctl_transfer_seq_initiative = -1;
static int hf_fc_fctl_rexmitted_seq = -1;
static int hf_fc_fctl_rel_offset = -1;
static int hf_fc_fctl_abts_ack = -1;
static int hf_fc_fctl_abts_not_ack = -1;
static int hf_fc_fctl_last_data_frame = -1;
static int hf_fc_fctl_ack_0_1 = -1;
static int hf_fc_seqid = -1;
static int hf_fc_dfctl = -1;
static int hf_fc_seqcnt = -1;
static int hf_fc_oxid = -1;
static int hf_fc_rxid = -1;
static int hf_fc_param = -1;
static int hf_fc_ftype = -1;    /* Derived field, non-existent in FC hdr */
static int hf_fc_reassembled = -1;
static int hf_fc_eisl = -1;

/* Network_Header fields */
static int hf_fc_nh_da = -1;
static int hf_fc_nh_sa = -1;

/* For Basic Link Svc */
static int hf_fc_bls_seqid_vld = -1;
static int hf_fc_bls_lastvld_seqid = -1;
static int hf_fc_bls_oxid = -1;
static int hf_fc_bls_rxid = -1;
static int hf_fc_bls_lowseqcnt = -1;
static int hf_fc_bls_hiseqcnt = -1;
static int hf_fc_bls_rjtcode = -1;
static int hf_fc_bls_rjtdetail = -1;
static int hf_fc_bls_vendor = -1;


/* Initialize the subtree pointers */
static gint ett_fc = -1;
static gint ett_fctl = -1;
static gint ett_fcbls = -1;

static dissector_table_t fcftype_dissector_table;
static dissector_handle_t data_handle;

static int fc_tap = -1;

/* Reassembly stuff */
static gboolean fc_reassemble = TRUE;
static guint32  fc_max_frame_size = 1024;
static GHashTable *fc_fragment_table = NULL;

typedef struct _fcseq_conv_key {
    guint32 conv_idx;
} fcseq_conv_key_t;

typedef struct _fcseq_conv_data {
    guint32 seq_cnt;
} fcseq_conv_data_t;

GHashTable *fcseq_req_hash = NULL;
GMemChunk *fcseq_req_keys = NULL;
GMemChunk *fcseq_req_vals = NULL;
guint32 fcseq_init_count = 25;

static GHashTable *fc_exchange_unmatched = NULL;
static GHashTable *fc_exchange_matched = NULL;
static GMemChunk *fc_exchange_vals = NULL;
static guint32 fc_exchange_init_count = 200;

/*
 * Hash Functions
 */
static gint
fcseq_equal(gconstpointer v, gconstpointer w)
{
  fcseq_conv_key_t *v1 = (fcseq_conv_key_t *)v;
  fcseq_conv_key_t *v2 = (fcseq_conv_key_t *)w;

  return (v1->conv_idx == v2->conv_idx);
}

static guint
fcseq_hash (gconstpointer v)
{
    fcseq_conv_key_t *key = (fcseq_conv_key_t *)v;
    guint val;
    
    val = key->conv_idx;
    
    return val;
}

static guint
fc_exchange_hash_unmatched(gconstpointer v)
{
    const fc_exchange_data *fced=(const fc_exchange_data *)v;

    return fced->oxid;
}
static gint
fc_exchange_equal_unmatched(gconstpointer v1, gconstpointer v2)
{
    const fc_exchange_data *fced1=(const fc_exchange_data *)v1;
    const fc_exchange_data *fced2=(const fc_exchange_data *)v2;

    /* oxid must match */
    if(fced1->oxid!=fced2->oxid){
        return 0;
    }
    /* compare s_id, d_id and treat the fc address
       s_id==00.00.00 as a wildcard matching anything */
    if( ((fced1->s_id.data[0]!=0)||(fced1->s_id.data[1]!=0)||(fced1->s_id.data[2]!=0)) && CMP_ADDRESS(&fced1->s_id, &fced2->s_id) ){
        return 0;
    }
    if(CMP_ADDRESS(&fced1->d_id, &fced2->d_id)){
        return 0;
    }

    return 1;
}

static guint
fc_exchange_hash_matched(gconstpointer v)
{
    const fc_exchange_data *fced=(const fc_exchange_data *)v;

    return fced->oxid;
}
static gint
fc_exchange_equal_matched(gconstpointer v1, gconstpointer v2)
{
    const fc_exchange_data *fced1=(const fc_exchange_data *)v1;
    const fc_exchange_data *fced2=(const fc_exchange_data *)v2;
    guint32 fef1, fef2, lef1, lef2;

    /* oxid must match */
    if(fced1->oxid!=fced2->oxid){
        return 0;
    }
    fef1=fced1->first_exchange_frame;
    fef2=fced2->first_exchange_frame;
    lef1=fced1->last_exchange_frame;
    lef2=fced2->last_exchange_frame;
    if(!fef1)fef1=fef2;
    if(!fef2)fef2=fef1;
    if(!lef1)lef1=lef2;
    if(!lef2)lef2=lef1;

    if(fef1!=fef2){
        return 0;
    }
    if(lef1!=lef2){
        return 0;
    }

    return 1;
}

static void
fc_exchange_init_protocol(void)
{
    if(fc_exchange_vals){
        g_mem_chunk_destroy(fc_exchange_vals);
        fc_exchange_vals=NULL;
    }
    if(fc_exchange_unmatched){
        g_hash_table_destroy(fc_exchange_unmatched);
        fc_exchange_unmatched=NULL;
    }
    if(fc_exchange_matched){
        g_hash_table_destroy(fc_exchange_matched);
        fc_exchange_matched=NULL;
    }

    fc_exchange_unmatched=g_hash_table_new(fc_exchange_hash_unmatched, fc_exchange_equal_unmatched);
    fc_exchange_matched=g_hash_table_new(fc_exchange_hash_matched, fc_exchange_equal_matched);
    fc_exchange_vals=g_mem_chunk_new("fc_exchange_vals", sizeof(fc_exchange_data), fc_exchange_init_count*sizeof(fc_exchange_data), G_ALLOC_AND_FREE);

    fragment_table_init(&fc_fragment_table);

    if (fcseq_req_keys)
        g_mem_chunk_destroy (fcseq_req_keys);
    if (fcseq_req_vals)
        g_mem_chunk_destroy (fcseq_req_vals);
    if (fcseq_req_hash)
        g_hash_table_destroy(fcseq_req_hash);
    
    fcseq_req_hash = g_hash_table_new(fcseq_hash, fcseq_equal);
    fcseq_req_keys = g_mem_chunk_new ("fcseq_req_keys",
                                      sizeof(fcseq_conv_key_t),
                                      fcseq_init_count *
                                      sizeof(fcseq_conv_key_t),
                                      G_ALLOC_AND_FREE);
    fcseq_req_vals = g_mem_chunk_new ("fcseq_req_vals",
                                      sizeof(fcseq_conv_data_t),
                                      fcseq_init_count *
                                      sizeof(fcseq_conv_data_t),
                                      G_ALLOC_AND_FREE);
}


const value_string fc_fc4_val[] = {
    {FC_TYPE_ELS,        "Ext Link Svc"},
    {FC_TYPE_LLCSNAP,    "LLC_SNAP"},
    {FC_TYPE_IP,         "IP/FC"},
    {FC_TYPE_SCSI,       "FCP"},
    {FC_TYPE_FCCT,       "FC_CT"},
    {FC_TYPE_SWILS,      "SW_ILS"},
    {FC_TYPE_AL,         "AL"},
    {FC_TYPE_SNMP,       "SNMP"},
    {FC_TYPE_SB_FROM_CU, "SB-3(CU->Channel)"},
    {FC_TYPE_SB_TO_CU,   "SB-3(Channel->CU)"},
    {0, NULL},
};

static const value_string fc_ftype_vals [] = {
    {FC_FTYPE_UNDEF ,    "Unknown frame"},
    {FC_FTYPE_SWILS,     "SW_ILS"},
    {FC_FTYPE_IP ,       "IP/FC"},
    {FC_FTYPE_SCSI ,     "FCP"},
    {FC_FTYPE_BLS ,      "Basic Link Svc"},
    {FC_FTYPE_ELS ,      "ELS"},
    {FC_FTYPE_FCCT ,     "FC_CT"},
    {FC_FTYPE_LINKDATA,  "Link Data"},
    {FC_FTYPE_VDO,       "Video Data"},
    {FC_FTYPE_LINKCTL,   "Link Ctl"},
    {FC_FTYPE_SBCCS,     "SBCCS"},
    {0, NULL},
};

static const value_string fc_wka_vals[] = {
    {FC_WKA_MULTICAST,    "Multicast Server"},
    {FC_WKA_CLKSYNC,      "Clock Sync Server"},
    {FC_WKA_KEYDIST,      "Key Distribution Server"},
    {FC_WKA_ALIAS,        "Alias Server"},
    {FC_WKA_QOSF,         "QoS Facilitator"},
    {FC_WKA_MGMT,         "Management Server"},
    {FC_WKA_TIME,         "Time Server"},
    {FC_WKA_DNS,          "Directory Server"},
    {FC_WKA_FABRIC_CTRLR, "Fabric Ctlr"},
    {FC_WKA_FPORT,        "F_Port Server"},
    {FC_WKA_BCAST,        "Broadcast ID"},
    {0, NULL},
};

static const value_string fc_routing_val[] = {
    {FC_RCTL_DEV_DATA,  "Device_Data"},
    {FC_RCTL_ELS,       "Extended Link Services"},
    {FC_RCTL_LINK_DATA, "FC-4 Link_Data"},
    {FC_RCTL_VIDEO,     "Video_Data"},
    {FC_RCTL_BLS,       "Basic Link Services"},
    {FC_RCTL_LINK_CTL,  "Link_Control Frame"},
    {0, NULL},
};

static const value_string fc_iu_val[] = {
    {FC_IU_UNCATEGORIZED   , "Uncategorized Data"},
    {FC_IU_SOLICITED_DATA  , "Solicited Data"},
    {FC_IU_UNSOLICITED_CTL , "Unsolicited Control"},
    {FC_IU_SOLICITED_CTL   , "Solicited Control"},
    {FC_IU_UNSOLICITED_DATA, "Solicited Data"},
    {FC_IU_DATA_DESCRIPTOR , "Data Descriptor"},
    {FC_IU_UNSOLICITED_CMD , "Unsolicited Command"},
    {FC_IU_CMD_STATUS      , "Command Status"},
    {0, NULL},
};


static void fc_defragment_init(void)
{
  fragment_table_init(&fc_fragment_table);
}


static gchar *
fctl_to_str (const guint8 *fctl, gchar *str, gboolean is_ack)
{
    int stroff = 0;
    guint8 tmp = 0;

    if (str == NULL)
        return (str);
    
    if (fctl[2] & 0x80) {
        strcpy (str, "Exchange Responder, ");
        stroff += 20;
    }
    else {
        strcpy (str, "Exchange Originator, ");
        stroff += 21;
    }

    if (fctl[2] & 0x40) {
        strcpy (&str[stroff], "Seq Recipient, ");
        stroff += 15;
    }
    else {
        strcpy (&str[stroff], "Seq Initiator, ");
        stroff += 15;
    }

    if (fctl[2] & 0x20) {
        strcpy (&str[stroff], "Exchg First, ");
        stroff += 13;
    }

    if (fctl[2] & 0x10) {
        strcpy (&str[stroff], "Exchg Last, ");
        stroff += 12;
    }

    if (fctl[2] & 0x8) {
        strcpy (&str[stroff], "Seq Last, ");
        stroff += 10;
    }

    if (fctl[2] & 0x2) {
        strcpy (&str[stroff], "Priority, ");
        stroff += 10;
    }
    else {
        strcpy (&str[stroff], "CS_CTL, ");
        stroff += 8;
    }

    if (fctl[2] & 0x1) {
        strcpy (&str[stroff], "Transfer Seq Initiative, ");
        stroff += 25;
    }

    if (fctl[1] & 0x30) {
        strcpy (&str[stroff], "ACK_0 Reqd, ");
        stroff += 12;
    }
    else if (fctl[1] & 0x10) {
        strcpy (&str[stroff], "ACK_1 Reqd, ");
        stroff += 12;
    }

    if (fctl[1] & 0x2) {
        strcpy (&str[stroff], "Rexmitted Seq, ");
        stroff += 15;
    }

    tmp = fctl[0] & 0xC0;
    switch (tmp) {
    case 0:
        strcpy (&str[stroff], "Last Data Frame - No Info, ");
        stroff += 27;
        break;
    case 1:
        strcpy (&str[stroff], "Last Data Frame - Seq Imm, ");
        stroff += 27;
        break;
    case 2:
        strcpy (&str[stroff], "Last Data Frame - Seq Soon, ");
        stroff += 28;
        break;
    case 3:
        strcpy (&str[stroff], "Last Data Frame - Seq Delyd, ");
        stroff += 29;
        break;
    }

    tmp = fctl[0] & 0x30;
    switch (tmp) {
    case 0:
        if (is_ack) {
            strcpy (&str[stroff], "ABTS - Cont, ");
            stroff += 13;
        }
        else {
            strcpy (&str[stroff], "ABTS - Abort/MS, ");
            stroff += 17;
        }
        break;
    case 0x10:
        if (is_ack) {
            strcpy (&str[stroff], "ABTS - AbortABTS - Abort, ");
            stroff += 14;
        }
        else {
            strcpy (&str[stroff], "ABTS - Abort/SS, ");
            stroff += 17;
        }
        break;
    case 0x20:
        if (is_ack) {
            strcpy (&str[stroff], "ABTS - Stop, ");
            stroff += 13;
        }
        else {
            strcpy (&str[stroff], "ABTS - Process/IB, ");
            stroff += 19;
        }
        break;
    case 0x30:
        if (is_ack) {
            strcpy (&str[stroff], "ABTS - Imm Seq Retx, ");
            stroff += 21;
        }
        else {
            strcpy (&str[stroff], "ABTS - Discard/MS/Imm Retx, ");
            stroff += 28;
        }
        break;
    }

    if (fctl[0] & 0x8) {
        strcpy (&str[stroff], "Rel Offset = 1");
        stroff += 14;
    }

    return (str);
}

/* BA_ACC & BA_RJT are decoded in this file itself instead of a traditional
 * dedicated file and dissector format because the dissector would require some
 * fields of the FC_HDR such as param in some cases, type in some others, the
 * lower 4 bits of r_ctl in some other cases etc. So, we decode BLS & Link Ctl
 * in this file itself.
 */
static void
dissect_fc_ba_acc (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    /* Set up structures needed to add the protocol subtree and manage it */
    proto_item *ti;
    proto_tree *acc_tree;
    int offset = 0;

    /* Make entries in Protocol column and Info column on summary display */
    if (check_col(pinfo->cinfo, COL_PROTOCOL)) 
        col_set_str(pinfo->cinfo, COL_PROTOCOL, "BLS");

    if (check_col(pinfo->cinfo, COL_INFO)) 
        col_set_str(pinfo->cinfo, COL_INFO, "BA_ACC");

    if (tree) {
        ti = proto_tree_add_text (tree, tvb, 0, tvb_length (tvb), "Basic Link Svc");
        acc_tree = proto_item_add_subtree (ti, ett_fcbls);

        proto_tree_add_item (acc_tree, hf_fc_bls_seqid_vld, tvb, offset++, 1, FALSE);
        proto_tree_add_item (acc_tree, hf_fc_bls_lastvld_seqid, tvb, offset++, 1, FALSE);
        offset += 2; /* Skip reserved field */
        proto_tree_add_item (acc_tree, hf_fc_bls_oxid, tvb, offset, 2, FALSE);
        offset += 2;
        proto_tree_add_item (acc_tree, hf_fc_bls_rxid, tvb, offset, 2, FALSE);
        offset += 2;
        proto_tree_add_item (acc_tree, hf_fc_bls_lowseqcnt, tvb, offset, 2, FALSE);
        offset += 2;
        proto_tree_add_item (acc_tree, hf_fc_bls_hiseqcnt, tvb, offset, 2, FALSE);
    }
}

static void
dissect_fc_ba_rjt (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    /* Set up structures needed to add the protocol subtree and manage it */
    proto_item *ti;
    proto_tree *rjt_tree;
    int offset = 0;

    /* Make entries in Protocol column and Info column on summary display */
    if (check_col(pinfo->cinfo, COL_PROTOCOL)) 
        col_set_str(pinfo->cinfo, COL_PROTOCOL, "BLS");

    if (check_col(pinfo->cinfo, COL_INFO)) 
        col_set_str(pinfo->cinfo, COL_INFO, "BA_RJT");

    if (tree) {
        ti = proto_tree_add_text (tree, tvb, 0, tvb_length (tvb), "Basic Link Svc");
        rjt_tree = proto_item_add_subtree (ti, ett_fcbls);

        proto_tree_add_item (rjt_tree, hf_fc_bls_rjtcode, tvb, offset+1, 1, FALSE);
        proto_tree_add_item (rjt_tree, hf_fc_bls_rjtdetail, tvb, offset+2, 1, FALSE);
        proto_tree_add_item (rjt_tree, hf_fc_bls_vendor, tvb, offset+3, 1, FALSE);
    }
}

static guint8
fc_get_ftype (guint8 r_ctl, guint8 type)
{
    /* A simple attempt to determine the upper level protocol based on the
     * r_ctl & type fields.
     */
    switch (r_ctl & 0xF0) {
    case FC_RCTL_DEV_DATA:
        switch (type) {
        case FC_TYPE_SWILS:
            if ((r_ctl == 0x2) || (r_ctl == 0x3))
                return FC_FTYPE_SWILS;
            else
                return FC_FTYPE_UNDEF;
        case FC_TYPE_IP:
            return FC_FTYPE_IP;
        case FC_TYPE_SCSI:
            return FC_FTYPE_SCSI;
        case FC_TYPE_FCCT:
            return FC_FTYPE_FCCT;
        case FC_TYPE_SB_FROM_CU:
        case FC_TYPE_SB_TO_CU:
            return FC_FTYPE_SBCCS;
        default:
            return FC_FTYPE_UNDEF;
        }
        break;
    case FC_RCTL_ELS:
        if (((r_ctl & 0x0F) == 0x2) || ((r_ctl & 0x0F) == 0x3))
            return FC_FTYPE_ELS;
        else
            return FC_FTYPE_UNDEF;
        break;
    case FC_RCTL_LINK_DATA:
        return FC_FTYPE_LINKDATA;
        break;
    case FC_RCTL_VIDEO:
        return FC_FTYPE_VDO;
        break;
    case FC_RCTL_BLS:
        if (type == 0)
            return FC_FTYPE_BLS;
        else
            return FC_FTYPE_UNDEF;
        break;
    case FC_RCTL_LINK_CTL:
        return FC_FTYPE_LINKCTL;
        break;
    default:
        return FC_FTYPE_UNDEF;
        break;
    }
}

static const value_string abts_ack_vals[] = {
	{0x000000,	"ABTS - Cont"},
	{0x000010,	"ABTS - Abort"},
	{0x000020,	"ABTS - Stop"},
	{0x000030,	"ABTS - Imm Seq Retx"},
	{0,NULL}
};
static const value_string abts_not_ack_vals[] = {
	{0x000000,	"ABTS - Abort/MS"},
	{0x000010,	"ABTS - Abort/SS"},
	{0x000020,	"ABTS - Process/IB"},
	{0x000030,	"ABTS - Discard/MS/Imm Retx"},
	{0,NULL}
};
static const value_string last_data_frame_vals[] = {
	{0x000000,	"Last Data Frame - No Info"},
	{0x004000,	"Last Data Frame - Seq Imm"},
	{0x008000,	"Last Data Frame - Seq Soon"},
	{0x00c000,	"Last Data Frame - Seq Delyd"},
	{0,NULL}
};
static const value_string ack_0_1_vals[] = {
	{0x003000,	"ACK_0 Required"},
	{0x002000,	"ACK_0 Required"},
	{0x001000,	"ACK_1 Required"},
	{0x000000,	"no ack required"},
	{0,NULL}
};
static const true_false_string tfs_fc_fctl_exchange_responder = {
	"Exchange Responder",
	"Exchange Originator"
};
static const true_false_string tfs_fc_fctl_seq_recipient = {
	"Seq Recipient",
	"Seq Initiator"
};
static const true_false_string tfs_fc_fctl_exchange_first = {
	"Exchg First",
	"NOT exchg first"
};
static const true_false_string tfs_fc_fctl_exchange_last = {
	"Exchg Last",
	"NOT exchg last"
};
static const true_false_string tfs_fc_fctl_seq_last = {
	"Seq Last",
	"NOT seq last"
};
static const true_false_string tfs_fc_fctl_priority = {
	"Priority",
	"CS_CTL"
};
static const true_false_string tfs_fc_fctl_transfer_seq_initiative = {
	"Transfer Seq Initiative",
	"NOT transfer seq initiative"
};
static const true_false_string tfs_fc_fctl_rexmitted_seq = {
	"Retransmitted Sequence",
	"NOT retransmitted sequence"
};
static const true_false_string tfs_fc_fctl_rel_offset = {
	"Rel Offset SET",
	"rel offset NOT set"
};




/* code to dissect the  F_CTL bitmask */
static void
dissect_fc_fctl(packet_info *pinfo _U_, proto_tree *parent_tree, tvbuff_t *tvb, int offset, gboolean is_ack, guint32 fctl)
{
	proto_item *item;
	proto_tree *tree;
	gchar str[256];

        item=proto_tree_add_uint(parent_tree, hf_fc_fctl, tvb, offset, 3, fctl);
	tree=proto_item_add_subtree(item, ett_fctl);


	proto_tree_add_boolean(tree, hf_fc_fctl_exchange_responder, tvb, offset, 3, fctl);

	proto_tree_add_boolean(tree, hf_fc_fctl_seq_recipient, tvb, offset, 3, fctl);

	proto_tree_add_boolean(tree, hf_fc_fctl_exchange_first, tvb, offset, 3, fctl);

	proto_tree_add_boolean(tree, hf_fc_fctl_exchange_last, tvb, offset, 3, fctl);

	proto_tree_add_boolean(tree, hf_fc_fctl_seq_last, tvb, offset, 3, fctl);

	proto_tree_add_boolean(tree, hf_fc_fctl_priority, tvb, offset, 3, fctl);

	proto_tree_add_boolean(tree, hf_fc_fctl_transfer_seq_initiative, tvb, offset, 3, fctl);

	proto_tree_add_uint(tree, hf_fc_fctl_last_data_frame, tvb, offset, 3, fctl);

	proto_tree_add_uint(tree, hf_fc_fctl_ack_0_1, tvb, offset, 3, fctl);


	proto_tree_add_boolean(tree, hf_fc_fctl_rexmitted_seq, tvb, offset, 3, fctl);

	if(is_ack){
		proto_tree_add_uint(tree, hf_fc_fctl_abts_ack, tvb, offset, 3, fctl);
	} else {
		proto_tree_add_uint(tree, hf_fc_fctl_abts_ack, tvb, offset, 3, fctl);
	}

	proto_tree_add_boolean(tree, hf_fc_fctl_rel_offset, tvb, offset, 3, fctl);

	fctl_to_str( ((guint8 *)&fctl), str, is_ack);
	proto_item_append_text(item, "  %s", str);
}

static const value_string fc_bls_proto_val[] = {
    {FC_BLS_NOP    , "NOP"},
    {FC_BLS_ABTS   , "ABTS"},
    {FC_BLS_RMC    , "RMC"},
    {FC_BLS_BAACC  , "BA_ACC"},
    {FC_BLS_BARJT  , "BA_RJT"},
    {FC_BLS_PRMT   , "PRMT"},
    {0, NULL},
};

static const value_string fc_els_proto_val[] = {
    {0x01    , "Solicited Data"},
    {0x02    , "Request"},
    {0x03    , "Reply"},
    {0, NULL},
};

/* Code to actually dissect the packets */
static void
dissect_fc (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
   /* Set up structures needed to add the protocol subtree and manage it */
    proto_item *ti=NULL;
    proto_tree *fc_tree = NULL;
    tvbuff_t *next_tvb;
    int offset = 0, next_offset, eisl_offset = -1;
    gboolean is_lastframe_inseq, is_1frame_inseq, is_valid_frame;
    gboolean is_exchg_resp = 0;
    fragment_data *fcfrag_head;
    guint32 frag_id;
    guint32 frag_size;
    guint8 df_ctl, seq_id;
    
    guint32 param;
    guint16 real_seqcnt;
    guint8 ftype;
    gboolean is_ack;

    static fc_hdr fchdr;
    fc_exchange_data *fc_ex=NULL;

    conversation_t *conversation;
    fcseq_conv_data_t *cdata;
    fcseq_conv_key_t ckey, *req_key;

    fchdr.fced=NULL;

    /* Make entries in Protocol column and Info column on summary display */
    if (check_col(pinfo->cinfo, COL_PROTOCOL)) 
        col_set_str(pinfo->cinfo, COL_PROTOCOL, "FC");

    fchdr.r_ctl = tvb_get_guint8 (tvb, offset);

    /* If the R_CTL is the EISL field, skip the first 8 bytes to retrieve the
     * real FC header. EISL is Cisco-proprietary and is not decoded.
     */
    if (fchdr.r_ctl == FC_RCTL_EISL) {
        eisl_offset = offset;
        offset += 8;
        fchdr.r_ctl = tvb_get_guint8 (tvb, offset);
    }
    
    SET_ADDRESS (&pinfo->dst, AT_FC, 3, tvb_get_ptr(tvb,offset+1,3));
    SET_ADDRESS (&fchdr.d_id, AT_FC, 3, tvb_get_ptr(tvb,offset+1,3));
    SET_ADDRESS (&pinfo->src, AT_FC, 3, tvb_get_ptr(tvb,offset+5,3));
    SET_ADDRESS (&fchdr.s_id, AT_FC, 3, tvb_get_ptr(tvb,offset+5,3));
    fchdr.cs_ctl = tvb_get_guint8 (tvb, offset+4);
    fchdr.type  = tvb_get_guint8 (tvb, offset+8);
    fchdr.fctl=tvb_get_ntoh24(tvb,offset+9);
    fchdr.seqcnt = tvb_get_ntohs (tvb, offset+14);
    fchdr.oxid=tvb_get_ntohs(tvb,offset+16);
    fchdr.rxid=tvb_get_ntohs(tvb,offset+18);
    param = tvb_get_ntohl (tvb, offset+20);
    seq_id = tvb_get_guint8 (tvb, offset+12);

    pinfo->oxid = fchdr.oxid;
    pinfo->rxid = fchdr.rxid;
    pinfo->ptype = PT_EXCHG;
    pinfo->r_ctl = fchdr.r_ctl;

    is_ack = ((fchdr.r_ctl == 0xC0) || (fchdr.r_ctl == 0xC1));

    /* There are two ways to determine if this is the first frame of a
     * sequence. Either:
     * (i) The SOF bits indicate that this is the first frame OR
     * (ii) This is an SOFf frame and seqcnt is 0.
     */
    is_1frame_inseq = (((pinfo->sof_eof & PINFO_SOF_FIRST_FRAME) == PINFO_SOF_FIRST_FRAME) ||
                       (((pinfo->sof_eof & PINFO_SOF_SOFF) == PINFO_SOF_SOFF) &&
                        (fchdr.seqcnt == 0)));
    
    is_lastframe_inseq = ((pinfo->sof_eof & PINFO_EOF_LAST_FRAME) == PINFO_EOF_LAST_FRAME);

    if ((pinfo->sof_eof & PINFO_SOF_SOFF) == PINFO_SOF_SOFF) {
        is_lastframe_inseq = fchdr.fctl & FC_FCTL_SEQ_LAST;
    }
    is_valid_frame = ((pinfo->sof_eof & 0x40) == 0x40);

    ftype = fc_get_ftype (fchdr.r_ctl, fchdr.type);
    
    if (check_col (pinfo->cinfo, COL_INFO)) {
        col_add_str (pinfo->cinfo, COL_INFO, match_strval (ftype, fc_ftype_vals));

        if (ftype == FC_FTYPE_LINKCTL)
            col_append_fstr (pinfo->cinfo, COL_INFO, ", %s",
                             match_strval ((fchdr.r_ctl & 0x0F),
                                           fc_lctl_proto_val));
    }
    
    /* In the interest of speed, if "tree" is NULL, don't do any work not
       necessary to generate protocol tree items. */
    if (tree) {
        ti = proto_tree_add_protocol_format (tree, proto_fc, tvb, offset,
                                             FC_HEADER_SIZE, "Fibre Channel");
        fc_tree = proto_item_add_subtree (ti, ett_fc);
    }

    /* Highlight EISL header, if present */
    if (eisl_offset != -1) {
        proto_tree_add_item (fc_tree, hf_fc_eisl, tvb, eisl_offset, 8, 0);
    }

    /* match first exchange with last exchange */
    if(fchdr.fctl&FC_FCTL_EXCHANGE_FIRST){
        if(!pinfo->fd->flags.visited){
            fc_exchange_data fced, *old_fced;

            /* first check if we already have seen this exchange and it
               is still open/unmatched. 
            */
            fced.oxid=fchdr.oxid;
            SET_ADDRESS(&fced.s_id, fchdr.s_id.type, fchdr.s_id.len, fchdr.s_id.data);
            SET_ADDRESS(&fced.d_id, fchdr.d_id.type, fchdr.d_id.len, fchdr.d_id.data);
            old_fced=g_hash_table_lookup(fc_exchange_unmatched, &fced);
            if(old_fced){
                g_hash_table_remove(fc_exchange_unmatched, old_fced);
            }
            old_fced=g_mem_chunk_alloc(fc_exchange_vals);
            old_fced->oxid=fchdr.oxid;
            COPY_ADDRESS(&old_fced->s_id, &fchdr.s_id);
            COPY_ADDRESS(&old_fced->d_id, &fchdr.d_id);
	    old_fced->first_exchange_frame=pinfo->fd->num;
            old_fced->fc_time.nsecs = pinfo->fd->abs_usecs*1000;
            old_fced->fc_time.secs = pinfo->fd->abs_secs;
            g_hash_table_insert(fc_exchange_unmatched, old_fced, old_fced);
            fc_ex=old_fced;
        } else {
            fc_exchange_data fced, *old_fced;
            fced.oxid=fchdr.oxid;
            fced.first_exchange_frame=pinfo->fd->num;
            fced.last_exchange_frame=0;
            old_fced=g_hash_table_lookup(fc_exchange_matched, &fced);
            fc_ex=old_fced;
        }
    }
    if(fchdr.fctl&FC_FCTL_EXCHANGE_LAST){
        if(!pinfo->fd->flags.visited){
            fc_exchange_data fced, *old_fced;

            fced.oxid=fchdr.oxid;
            SET_ADDRESS(&fced.s_id, fchdr.d_id.type, fchdr.d_id.len, fchdr.d_id.data);
            SET_ADDRESS(&fced.d_id, fchdr.s_id.type, fchdr.s_id.len, fchdr.s_id.data);
            old_fced=g_hash_table_lookup(fc_exchange_unmatched, &fced);
            if(old_fced){
                g_hash_table_remove(fc_exchange_unmatched, old_fced);
                old_fced->last_exchange_frame=pinfo->fd->num;
                g_hash_table_insert(fc_exchange_matched, old_fced, old_fced);
            }
            fc_ex=old_fced;
        } else {
            fc_exchange_data fced, *old_fced;
            fced.oxid=fchdr.oxid;
            fced.first_exchange_frame=0;
            fced.last_exchange_frame=pinfo->fd->num;
            old_fced=g_hash_table_lookup(fc_exchange_matched, &fced);
            fc_ex=old_fced;
        }
    }
    if(fc_ex){
        if(fchdr.fctl&FC_FCTL_EXCHANGE_FIRST){
            proto_tree_add_uint(fc_tree, hf_fc_exchange_last_frame, tvb, 0, 0, fc_ex->last_exchange_frame);
        }
        if(fchdr.fctl&FC_FCTL_EXCHANGE_LAST){
            nstime_t delta_time;
            proto_tree_add_uint(fc_tree, hf_fc_exchange_first_frame, tvb, 0, 0, fc_ex->first_exchange_frame);
            delta_time.secs = pinfo->fd->abs_secs - fc_ex->fc_time.secs;
            delta_time.nsecs = pinfo->fd->abs_usecs*1000 - fc_ex->fc_time.nsecs;
            if (delta_time.nsecs<0){
                delta_time.nsecs+=1000000000;
                delta_time.secs--;
            }
            proto_tree_add_time(ti, hf_fc_time, tvb, 0, 0, &delta_time);
        }
    }
    fchdr.fced=fc_ex;

    switch (fchdr.r_ctl & 0xF0) {

    case FC_RCTL_DEV_DATA:
    case FC_RCTL_LINK_DATA:
    case FC_RCTL_VIDEO:
        /* the lower 4 bits of R_CTL are the information category */
        proto_tree_add_uint_format (fc_tree, hf_fc_rctl, tvb, offset,
                                    FC_RCTL_SIZE, fchdr.r_ctl,
                                    "R_CTL: 0x%x(%s/%s)",
                                    fchdr.r_ctl,
                                    val_to_str ((fchdr.r_ctl & 0xF0),
                                                fc_routing_val, "0x%x"),
                                    val_to_str ((fchdr.r_ctl & 0x0F),
                                                fc_iu_val, "0x%x")); 
        break;

    case FC_RCTL_LINK_CTL:
        /* the lower 4 bits of R_CTL indicate the type of link ctl frame */
        proto_tree_add_uint_format (fc_tree, hf_fc_rctl, tvb, offset,
                                    FC_RCTL_SIZE, fchdr.r_ctl,
                                    "R_CTL: 0x%x(%s/%s)",
                                    fchdr.r_ctl,
                                    val_to_str ((fchdr.r_ctl & 0xF0),
                                                fc_routing_val, "0x%x"),
                                    val_to_str ((fchdr.r_ctl & 0x0F),
                                                fc_lctl_proto_val, "0x%x")); 
        break;

    case FC_RCTL_BLS:
        switch (fchdr.type) {

        case 0x00:
            /* the lower 4 bits of R_CTL indicate the type of BLS frame */
            proto_tree_add_uint_format (fc_tree, hf_fc_rctl, tvb, offset,
                                        FC_RCTL_SIZE, fchdr.r_ctl,
                                        "R_CTL: 0x%x(%s/%s)",
                                        fchdr.r_ctl,
                                        val_to_str ((fchdr.r_ctl & 0xF0),
                                                    fc_routing_val, "0x%x"),
                                        val_to_str ((fchdr.r_ctl & 0x0F),
                                                    fc_bls_proto_val, "0x%x")); 
            break;

        default:
            proto_tree_add_uint_format (fc_tree, hf_fc_rctl, tvb, offset,
                                        FC_RCTL_SIZE, fchdr.r_ctl,
                                        "R_CTL: 0x%x(%s/0x%x)",
                                        fchdr.r_ctl,
                                        val_to_str ((fchdr.r_ctl & 0xF0),
                                                    fc_routing_val, "0x%x"),
                                        fchdr.r_ctl & 0x0F);
            break;
        }
        break;

    case FC_RCTL_ELS:
        switch (fchdr.type) {

        case 0x01:
            /* the lower 4 bits of R_CTL indicate the type of ELS frame */
            proto_tree_add_uint_format (fc_tree, hf_fc_rctl, tvb, offset,
                                        FC_RCTL_SIZE, fchdr.r_ctl,
                                        "R_CTL: 0x%x(%s/%s)",
                                        fchdr.r_ctl,
                                        val_to_str ((fchdr.r_ctl & 0xF0),
                                                    fc_routing_val, "0x%x"),
                                        val_to_str ((fchdr.r_ctl & 0x0F),
                                                    fc_els_proto_val, "0x%x")); 
            break;

        default:
            proto_tree_add_uint_format (fc_tree, hf_fc_rctl, tvb, offset,
                                        FC_RCTL_SIZE, fchdr.r_ctl,
                                        "R_CTL: 0x%x(%s/0x%x)",
                                        fchdr.r_ctl,
                                        val_to_str ((fchdr.r_ctl & 0xF0),
                                                    fc_routing_val, "0x%x"),
                                        fchdr.r_ctl & 0x0F);
            break;
        }
        break;

    default:
        proto_tree_add_uint_format (fc_tree, hf_fc_rctl, tvb, offset,
                                    FC_RCTL_SIZE, fchdr.r_ctl,
                                    "R_CTL: 0x%x(%s/0x%x)",
                                    fchdr.r_ctl,
                                    val_to_str ((fchdr.r_ctl & 0xF0),
                                                fc_routing_val, "0x%x"),
                                    fchdr.r_ctl & 0x0F);
        break;
    }
        
    proto_tree_add_uint_hidden (fc_tree, hf_fc_ftype, tvb, offset, 1,
                           ftype); 

    /* XXX - use "fc_wka_vals[]" on this? */
    proto_tree_add_string (fc_tree, hf_fc_did, tvb, offset+1, 3,
                           fc_to_str (fchdr.d_id.data));
    proto_tree_add_string_hidden (fc_tree, hf_fc_id, tvb, offset+1, 3,
                           fc_to_str (fchdr.d_id.data));

    proto_tree_add_uint (fc_tree, hf_fc_csctl, tvb, offset+4, 1, fchdr.cs_ctl);

    /* XXX - use "fc_wka_vals[]" on this? */
    proto_tree_add_string (fc_tree, hf_fc_sid, tvb, offset+5, 3,
                           fc_to_str (fchdr.s_id.data));
    proto_tree_add_string_hidden (fc_tree, hf_fc_id, tvb, offset+5, 3,
                           fc_to_str (fchdr.s_id.data));
        
    if (ftype == FC_FTYPE_LINKCTL) {
        if (((fchdr.r_ctl & 0x0F) == FC_LCTL_FBSYB) ||
            ((fchdr.r_ctl & 0x0F) == FC_LCTL_FBSYL)) {
            /* for F_BSY frames, the upper 4 bits of the type field specify the
             * reason for the BSY.
             */
            proto_tree_add_uint_format (fc_tree, hf_fc_type, tvb,
                                        offset+8, FC_TYPE_SIZE,
                                        fchdr.type,"Type: 0x%x(%s)", fchdr.type, 
                                        fclctl_get_typestr ((guint8) (fchdr.r_ctl & 0x0F),
                                                            fchdr.type));
        } else {
            proto_tree_add_item (fc_tree, hf_fc_type, tvb, offset+8, 1, FALSE);
        }
    } else {
        proto_tree_add_item (fc_tree, hf_fc_type, tvb, offset+8, 1, FALSE);
    }


    dissect_fc_fctl(pinfo, fc_tree, tvb, offset+9, is_ack, fchdr.fctl);


    proto_tree_add_item (fc_tree, hf_fc_seqid, tvb, offset+12, 1, FALSE);

    df_ctl = tvb_get_guint8(tvb, offset+13);

    proto_tree_add_uint (fc_tree, hf_fc_dfctl, tvb, offset+13, 1, df_ctl);
    proto_tree_add_uint (fc_tree, hf_fc_seqcnt, tvb, offset+14, 2, fchdr.seqcnt);
    proto_tree_add_uint (fc_tree, hf_fc_oxid, tvb, offset+16, 2, fchdr.oxid);
    proto_tree_add_uint (fc_tree, hf_fc_rxid, tvb, offset+18, 2, fchdr.rxid);

    if (ftype == FC_FTYPE_LINKCTL) {
        if (((fchdr.r_ctl & 0x0F) == FC_LCTL_FRJT) ||
            ((fchdr.r_ctl & 0x0F) == FC_LCTL_PRJT) ||
            ((fchdr.r_ctl & 0x0F) == FC_LCTL_PBSY)) {
            /* In all these cases of Link Ctl frame, the parameter field
             * encodes the detailed error message
             */
            proto_tree_add_uint_format (fc_tree, hf_fc_param, tvb,
                                        offset+20, 4, param,
                                        "Parameter: 0x%x(%s)", param,
                                        fclctl_get_paramstr ((fchdr.r_ctl & 0x0F),
                                                             param));
        } else {
            proto_tree_add_item (fc_tree, hf_fc_param, tvb, offset+20, 4, FALSE);
        }
    } else if (ftype == FC_FTYPE_BLS) {
        if ((fchdr.r_ctl & 0x0F) == FC_BLS_ABTS) {
            proto_tree_add_uint_format (fc_tree, hf_fc_param, tvb,
                                        offset+20, 4, param, 
                                        "Parameter: 0x%x(%s)", param,
                                        ((param & 0x0F) == 1 ? "Abort Sequence" :
                                         "Abort Exchange"));
        } else {
            proto_tree_add_item (fc_tree, hf_fc_param, tvb, offset+20,
                                 4, FALSE);
        }
    } else {
        proto_tree_add_item (fc_tree, hf_fc_param, tvb, offset+20, 4, FALSE);
    }

    /* Skip the Frame_Header */
    next_offset = offset + FC_HEADER_SIZE;

    /* Network_Header present? */
    if (df_ctl & FC_DFCTL_NH) {
        /* Yes - dissect it. */
        if (tree) {
            proto_tree_add_string (fc_tree, hf_fc_nh_da, tvb, next_offset, 8,
                                   fcwwn_to_str (tvb_get_ptr (tvb, offset, 8)));
            proto_tree_add_string (fc_tree, hf_fc_nh_sa, tvb, offset+8, 8,
                                   fcwwn_to_str (tvb_get_ptr (tvb, offset+8, 8)));
        }
        next_offset += 16;
    }

    /* XXX - handle Association_Header and Device_Header here */

    if (ftype == FC_FTYPE_LINKCTL) {
        /* ACK_1 frames and other LINK_CTL frames echo the last seq bit if the
         * packet they're ack'ing did not have it set. So, we'll incorrectly
         * flag them as being fragmented when they're not. This fixes the
         * problem
         */
        is_lastframe_inseq = TRUE;
    } else {
	/* XXX is this right?   offset 20, shouldnt it be offset 9? */
        is_exchg_resp = ((tvb_get_guint8 (tvb, offset+20) & 0x80) == 0x80);
    }

    frag_size = tvb_reported_length (tvb)-FC_HEADER_SIZE;

    /* If there is an MDS header, we need to subtract the MDS trailer size */
    if ((pinfo->ethertype == ETHERTYPE_UNK) || (pinfo->ethertype == ETHERTYPE_FCFT)) {
        frag_size -= MDSHDR_TRAILER_SIZE;
    } else if (pinfo->ethertype == ETHERTYPE_BRDWALK) {
        frag_size -= 8;         /* 4 byte of FC CRC +
                                   4 bytes of error+EOF = 8 bytes  */
    }

    if (!is_lastframe_inseq) {
        /* Show this only as a fragmented FC frame */
        if (check_col (pinfo->cinfo, COL_INFO)) {
            col_append_str (pinfo->cinfo, COL_INFO, " (Fragmented)");
        }
    }

    /* If this is a fragment, attempt to check if fully reassembled frame is
     * present, if we're configured to reassemble.
     */
    if ((ftype != FC_FTYPE_LINKCTL) && (ftype != FC_FTYPE_BLS) &&
        (!is_lastframe_inseq || !is_1frame_inseq) && fc_reassemble &&
        tvb_bytes_exist(tvb, FC_HEADER_SIZE, frag_size) && tree) {
        /* Add this to the list of fragments */

        /* In certain cases such as FICON, the SEQ_CNT is streaming
         * i.e. continuously increasing. So, zero does not signify the
         * first frame of the sequence. To fix this, we need to save the
         * SEQ_CNT of the first frame in sequence and use this value to
         * determine the actual offset into a frame.
         */
        conversation = find_conversation (&pinfo->src, &pinfo->dst,
                                          pinfo->ptype, pinfo->oxid,
                                          pinfo->rxid, NO_PORT2);
        if (!conversation) {
            conversation = conversation_new (&pinfo->src, &pinfo->dst,
                                             pinfo->ptype, pinfo->oxid,
                                             pinfo->rxid, NO_PORT2);
        }
        
        ckey.conv_idx = conversation->index;
        
        cdata = (fcseq_conv_data_t *)g_hash_table_lookup (fcseq_req_hash,
                                                          &ckey);

        if (is_1frame_inseq) {
            if (cdata) {
                /* Since we never free the memory used by an exchange, this maybe a
                 * case of another request using the same exchange as a previous
                 * req. 
                 */
                cdata->seq_cnt = fchdr.seqcnt;
            }
            else {
                req_key = g_mem_chunk_alloc (fcseq_req_keys);
                req_key->conv_idx = conversation->index;
                
                cdata = g_mem_chunk_alloc (fcseq_req_vals);
                cdata->seq_cnt = fchdr.seqcnt;
                
                g_hash_table_insert (fcseq_req_hash, req_key, cdata);
            }
            real_seqcnt = 0;
        }
        else if (cdata != NULL) {
            real_seqcnt = fchdr.seqcnt - cdata->seq_cnt ;
        }
        else {
            real_seqcnt = fchdr.seqcnt;
        }
        
        frag_id = ((pinfo->oxid << 16) ^ seq_id) | is_exchg_resp ;

        /* We assume that all frames are of the same max size */
        fcfrag_head = fragment_add (tvb, FC_HEADER_SIZE, pinfo, frag_id,
                                    fc_fragment_table,
                                    real_seqcnt * fc_max_frame_size,
                                    frag_size,
                                    !is_lastframe_inseq);
        
        if (fcfrag_head) {
            next_tvb = tvb_new_real_data (fcfrag_head->data,
                                          fcfrag_head->datalen,
                                          fcfrag_head->datalen);
            tvb_set_child_real_data_tvbuff(tvb, next_tvb);
            
            /* Add the defragmented data to the data source list. */
            add_new_data_source(pinfo, next_tvb, "Reassembled FC");
            
            if (tree) {
                proto_tree_add_boolean_hidden (fc_tree, hf_fc_reassembled,
                                               tvb, offset+9, 1, 1);
            }
        }
        else {
            if (tree) {
                proto_tree_add_boolean_hidden (fc_tree, hf_fc_reassembled,
                                               tvb, offset+9, 1, 0);
            }
            next_tvb = tvb_new_subset (tvb, next_offset, -1, -1);
            call_dissector (data_handle, next_tvb, pinfo, tree);
            return;
        }
    } else {
        if (tree) {
            proto_tree_add_boolean_hidden (fc_tree, hf_fc_reassembled,
                                           tvb, offset+9, 1, 0);
        }
        next_tvb = tvb_new_subset (tvb, next_offset, -1, -1);
    }

    if ((ftype != FC_FTYPE_LINKCTL) && (ftype != FC_FTYPE_BLS)) {
        if (!dissector_try_port (fcftype_dissector_table, ftype, next_tvb,
                                 pinfo, tree)) {
            call_dissector (data_handle, next_tvb, pinfo, tree);
        }
    } else if (ftype == FC_FTYPE_BLS) {
        if ((fchdr.r_ctl & 0x0F) == FC_BLS_BAACC) {
            dissect_fc_ba_acc (next_tvb, pinfo, tree);
        } else if ((fchdr.r_ctl & 0x0F) == FC_BLS_BARJT) {
            dissect_fc_ba_rjt (next_tvb, pinfo, tree);
        }
    }

    tap_queue_packet(fc_tap, pinfo, &fchdr);
}


/* Register the protocol with Ethereal */

/* this format is require because a script is used to build the C function
   that calls all the protocol registration.
*/

void
proto_register_fc(void)
{                 

/* Setup list of header fields  See Section 1.6.1 for details*/
    static hf_register_info hf[] = {
        { &hf_fc_rctl,
          { "R_CTL", "fc.r_ctl", FT_UINT8, BASE_HEX, NULL, 0x0,
            "R_CTL", HFILL }},
        { &hf_fc_ftype,
          {"Frame type", "fc.ftype", FT_UINT8, BASE_HEX, VALS(fc_ftype_vals),
           0x0, "Derived Type", HFILL}},
        { &hf_fc_did,
          { "Dest Addr", "fc.d_id", FT_STRING, BASE_HEX, NULL, 0x0,
            "Destination Address", HFILL}},
        { &hf_fc_csctl,
          {"CS_CTL", "fc.cs_ctl", FT_UINT8, BASE_HEX, NULL, 0x0,
           "CS_CTL", HFILL}},
        { &hf_fc_sid,
          {"Src Addr", "fc.s_id", FT_STRING, BASE_HEX, NULL, 0x0,
           "Source Address", HFILL}},
        { &hf_fc_id,
          {"Addr", "fc.id", FT_STRING, BASE_HEX, NULL, 0x0,
           "Source or Destination Address", HFILL}},
        { &hf_fc_type,
          {"Type", "fc.type", FT_UINT8, BASE_HEX, VALS (fc_fc4_val), 0x0,
           "", HFILL}},
        { &hf_fc_fctl,
          {"F_CTL", "fc.f_ctl", FT_UINT24, BASE_HEX, NULL, 0x0, "", HFILL}},
        { &hf_fc_seqid,
          {"SEQ_ID", "fc.seq_id", FT_UINT8, BASE_HEX, NULL, 0x0,
           "Sequence ID", HFILL}},
        { &hf_fc_dfctl,
          {"DF_CTL", "fc.df_ctl", FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL}},
        { &hf_fc_seqcnt,
          {"SEQ_CNT", "fc.seq_cnt", FT_UINT16, BASE_DEC, NULL, 0x0,
           "Sequence Count", HFILL}},
        { &hf_fc_oxid,
          {"OX_ID", "fc.ox_id", FT_UINT16, BASE_HEX, NULL, 0x0, "Originator ID",
           HFILL}},
        { &hf_fc_rxid,
          {"RX_ID", "fc.rx_id", FT_UINT16, BASE_HEX, NULL, 0x0, "Receiver ID",
           HFILL}},
        { &hf_fc_param,
          {"Parameter", "fc.parameter", FT_UINT32, BASE_HEX, NULL, 0x0, "Parameter",
           HFILL}},

        { &hf_fc_reassembled,
          {"Reassembled Frame", "fc.reassembled", FT_BOOLEAN, BASE_HEX, NULL,
           0x0, "", HFILL}},
        { &hf_fc_nh_da,
          {"Network DA", "fc.nethdr.da", FT_STRING, BASE_HEX, NULL,
           0x0, "", HFILL}},
        { &hf_fc_nh_sa,
          {"Network SA", "fc.nethdr.sa", FT_STRING, BASE_HEX, NULL,
           0x0, "", HFILL}},

        /* Basic Link Svc field definitions */
        { &hf_fc_bls_seqid_vld,
          {"SEQID Valid", "fc.bls_seqidvld", FT_UINT8, BASE_HEX,
           VALS (fc_bls_seqid_val), 0x0, "", HFILL}},
        { &hf_fc_bls_lastvld_seqid,
          {"Last Valid SEQID", "fc.bls_lastseqid", FT_UINT8, BASE_HEX, NULL,
           0x0, "", HFILL}},
        { &hf_fc_bls_oxid,
          {"OXID", "fc.bls_oxid", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL}},
        { &hf_fc_bls_rxid,
          {"RXID", "fc.bls_rxid", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL}},
        { &hf_fc_bls_lowseqcnt,
          {"Low SEQCNT", "fc.bls_lseqcnt", FT_UINT16, BASE_HEX, NULL, 0x0, "",
           HFILL}},
        { &hf_fc_bls_hiseqcnt,
          {"High SEQCNT", "fc.bls_hseqcnt", FT_UINT16, BASE_HEX, NULL, 0x0, "",
           HFILL}},
        { &hf_fc_bls_rjtcode,
          {"Reason", "fc.bls_reason", FT_UINT8, BASE_HEX, VALS(fc_bls_barjt_val),
           0x0, "", HFILL}},
        { &hf_fc_bls_rjtdetail,
          {"Reason Explanantion", "fc.bls_rjtdetail", FT_UINT8, BASE_HEX,
           VALS (fc_bls_barjt_det_val), 0x0, "", HFILL}},
        { &hf_fc_bls_vendor,
          {"Vendor Unique Reason", "fc.bls_vnduniq", FT_UINT8, BASE_HEX, NULL,
           0x0, "", HFILL}},
        { &hf_fc_fctl_exchange_responder,
          {"ExgRpd", "fc.fctl.exchange_responder", FT_BOOLEAN, 24, TFS(&tfs_fc_fctl_exchange_responder),
           FC_FCTL_EXCHANGE_RESPONDER, "Exchange Responder?", HFILL}},
        { &hf_fc_fctl_seq_recipient,
          {"SeqRec", "fc.fctl.seq_recipient", FT_BOOLEAN, 24, TFS(&tfs_fc_fctl_seq_recipient),
           FC_FCTL_SEQ_RECIPIENT, "Seq Recipient?", HFILL}},
        { &hf_fc_fctl_exchange_first,
          {"ExgFst", "fc.fctl.exchange_first", FT_BOOLEAN, 24, TFS(&tfs_fc_fctl_exchange_first),
           FC_FCTL_EXCHANGE_FIRST, "First Exchange?", HFILL}},
        { &hf_fc_fctl_exchange_last,
          {"ExgLst", "fc.fctl.exchange_last", FT_BOOLEAN, 24, TFS(&tfs_fc_fctl_exchange_last),
           FC_FCTL_EXCHANGE_LAST, "Last Exchange?", HFILL}},
        { &hf_fc_fctl_seq_last,
          {"SeqLst", "fc.fctl.seq_last", FT_BOOLEAN, 24, TFS(&tfs_fc_fctl_seq_last),
           FC_FCTL_SEQ_LAST, "Last Sequence?", HFILL}},
        { &hf_fc_fctl_priority,
          {"Pri", "fc.fctl.priority", FT_BOOLEAN, 24, TFS(&tfs_fc_fctl_priority),
           FC_FCTL_PRIORITY, "Priority", HFILL}},
        { &hf_fc_fctl_transfer_seq_initiative,
          {"TSI", "fc.fctl.transfer_seq_initiative", FT_BOOLEAN, 24, TFS(&tfs_fc_fctl_transfer_seq_initiative),
           FC_FCTL_TRANSFER_SEQ_INITIATIVE, "Transfer Seq Initiative", HFILL}},
        { &hf_fc_fctl_rexmitted_seq,
          {"RetSeq", "fc.fctl.rexmitted_seq", FT_BOOLEAN, 24, TFS(&tfs_fc_fctl_rexmitted_seq),
           FC_FCTL_REXMITTED_SEQ, "Retransmitted Sequence", HFILL}},
        { &hf_fc_fctl_rel_offset,
          {"RelOff", "fc.fctl.rel_offset", FT_BOOLEAN, 24, TFS(&tfs_fc_fctl_rel_offset),
           FC_FCTL_REL_OFFSET, "rel offset", HFILL}},
        { &hf_fc_fctl_last_data_frame,
          {"LDF", "fc.fctl.last_data_frame", FT_UINT24, BASE_HEX, VALS(last_data_frame_vals),
           FC_FCTL_LAST_DATA_FRAME_MASK, "Last Data Frame?", HFILL}},
        { &hf_fc_fctl_ack_0_1,
          {"A01", "fc.fctl.ack_0_1", FT_UINT24, BASE_HEX, VALS(ack_0_1_vals),
           FC_FCTL_ACK_0_1_MASK, "Ack 0/1 value", HFILL}},
        { &hf_fc_fctl_abts_ack,
          {"AA", "fc.fctl.abts_ack", FT_UINT24, BASE_HEX, VALS(abts_ack_vals),
           FC_FCTL_ABTS_MASK, "ABTS ACK values", HFILL}},
        { &hf_fc_fctl_abts_not_ack,
          {"AnA", "fc.fctl.abts_not_ack", FT_UINT24, BASE_HEX, VALS(abts_not_ack_vals),
           FC_FCTL_ABTS_MASK, "ABTS not ACK vals", HFILL}},
        { &hf_fc_exchange_first_frame,
          { "Exchange First In", "fc.exchange_first_frame", FT_FRAMENUM, BASE_NONE, NULL,
           0, "The first frame of this exchange is in this frame", HFILL }},
        { &hf_fc_exchange_last_frame,
          { "Exchange Last In", "fc.exchange_last_frame", FT_FRAMENUM, BASE_NONE, NULL,
           0, "The last frame of this exchange is in this frame", HFILL }},
        { &hf_fc_time,
          { "Time from Exchange First", "fc.time", FT_RELATIVE_TIME, BASE_NONE, NULL,
           0, "Time since the first frame of the Exchange", HFILL }},
        { &hf_fc_eisl,
          {"EISL Header", "fc.eisl", FT_BYTES, BASE_HEX, NULL, 0, "EISL Header", HFILL}},
    };

    /* Setup protocol subtree array */
    static gint *ett[] = {
        &ett_fc,
        &ett_fcbls,
	&ett_fctl
    };

    module_t *fc_module;

    /* Register the protocol name and description */
    proto_fc = proto_register_protocol ("Fibre Channel", "FC", "fc");
    register_dissector ("fc", dissect_fc, proto_fc);
    fc_tap = register_tap("fc");

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

    fcftype_dissector_table = register_dissector_table ("fc.ftype",
                                                        "FC Frame Type",
                                                        FT_UINT8, BASE_HEX);

    /* Register preferences */
    fc_module = prefs_register_protocol (proto_fc, NULL);
    prefs_register_bool_preference (fc_module,
                                    "reassemble",
                                    "Reassemble multi-frame sequences",
                                    "If enabled, reassembly of multi-frame "
                                    "sequences is done",
                                    &fc_reassemble);
    prefs_register_uint_preference (fc_module,
                                    "max_frame_size", "Max FC Frame Size",
                                    "This is the size of non-last frames in a "
                                    "multi-frame sequence", 10,
                                    &fc_max_frame_size);
    
    register_init_routine(fc_defragment_init);
    register_init_routine (fc_exchange_init_protocol);
}


/* If this dissector uses sub-dissector registration add a registration routine.
   This format is required because a script is used to find these routines and
   create the code that calls these routines.
*/
void
proto_reg_handoff_fc (void)
{
    data_handle = find_dissector("data");
}