aboutsummaryrefslogtreecommitdiffstats
path: root/epan/dissectors/packet-clnp.c
blob: 117028b595c40997ddad3be81cb0216cc74bb26f (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
/* packet-clnp.c
 * Routines for ISO/OSI network protocol packet disassembly
 *
 * Laurent Deniel <laurent.deniel@free.fr>
 * Ralf Schneider <Ralf.Schneider@t-online.de>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <glib.h>

#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/reassemble.h>
#include <epan/expert.h>
#include <epan/nlpid.h>

#include "packet-osi.h"
#include "packet-osi-options.h"

void proto_register_clnp(void);
void proto_reg_handoff_clnp(void);

/* protocols and fields */

static int  proto_clnp         = -1;
static gint ett_clnp           = -1;
static gint ett_clnp_type      = -1;
static gint ett_clnp_segments  = -1;
static gint ett_clnp_segment   = -1;
static gint ett_clnp_disc_pdu  = -1;

static int hf_clnp_id          = -1;
static int hf_clnp_length      = -1;
static int hf_clnp_version     = -1;
static int hf_clnp_ttl         = -1;
static int hf_clnp_type        = -1;
static int hf_clnp_cnf_segmentation         = -1;
static int hf_clnp_cnf_more_segments        = -1;
static int hf_clnp_cnf_report_error         = -1;
static int hf_clnp_cnf_type    = -1;
static int hf_clnp_pdu_length  = -1;
static int hf_clnp_data_unit_identifier     = -1;
static int hf_clnp_segment_offset           = -1;
static int hf_clnp_total_length             = -1;
static int hf_clnp_checksum    = -1;
static int hf_clnp_dest_length = -1;
static int hf_clnp_dest        = -1;
static int hf_clnp_src_length  = -1;
static int hf_clnp_src         = -1;
       int hf_clnp_atntt       = -1; /* as referenced in packet-osi-options.c */
       int hf_clnp_atnsc       = -1; /* as referenced in packet-osi-options.c */
static int hf_clnp_segments    = -1;
static int hf_clnp_segment     = -1;
static int hf_clnp_segment_overlap          = -1;
static int hf_clnp_segment_overlap_conflict = -1;
static int hf_clnp_segment_multiple_tails   = -1;
static int hf_clnp_segment_too_long_segment = -1;
static int hf_clnp_segment_error            = -1;
static int hf_clnp_segment_count            = -1;
static int hf_clnp_reassembled_in           = -1;
static int hf_clnp_reassembled_length       = -1;

static const fragment_items clnp_frag_items = {
    &ett_clnp_segment,
    &ett_clnp_segments,
    &hf_clnp_segments,
    &hf_clnp_segment,
    &hf_clnp_segment_overlap,
    &hf_clnp_segment_overlap_conflict,
    &hf_clnp_segment_multiple_tails,
    &hf_clnp_segment_too_long_segment,
    &hf_clnp_segment_error,
    &hf_clnp_segment_count,
    &hf_clnp_reassembled_in,
    &hf_clnp_reassembled_length,
    /* Reassembled data field */
    NULL,
    "segments"
};

static expert_field ei_clnp_length = EI_INIT;

static dissector_handle_t clnp_handle;
static dissector_handle_t ositp_handle;
static dissector_handle_t ositp_inactive_handle;
static dissector_handle_t idrp_handle;
static dissector_handle_t data_handle;

/*
 * ISO 8473 OSI CLNP definition (see RFC994)
 *
 *            _________________________________
 *           |           Fixed Part            |
 *           |_________________________________|
 *           |          Address Part           |
 *           |_________________________________|
 *           |   Segmentation Part (optional)  |
 *           |_________________________________|
 *           |     Options Part (optional)     |
 *           |_________________________________|
 *           |         Data (optional)         |
 *           |_________________________________|
 */

#define ISO8473_V1  0x01    /* CLNP version 1 */

/* Fixed part */

/* Length of fixed part */
#define FIXED_PART_LEN          9

#define CNF_TYPE                0x1f
#define CNF_ERR_OK              0x20
#define CNF_MORE_SEGS           0x40
#define CNF_SEG_OK              0x80

#define DT_NPDU                 0x1C
#define MD_NPDU                 0x1D
#define ER_NPDU                 0x01
#define ERQ_NPDU                0x1E
#define ERP_NPDU                0x1F

static const value_string npdu_type_abbrev_vals[] = {
    { DT_NPDU,    "DT" },
    { MD_NPDU,    "MD" },
    { ER_NPDU,    "ER" },
    { ERQ_NPDU,   "ERQ" },
    { ERP_NPDU,   "ERP" },
    { 0,          NULL }
};

static const value_string npdu_type_vals[] = {
    { DT_NPDU,    "Data" },
    { MD_NPDU,    "Multicast Data" },
    { ER_NPDU,    "Error Report" },
    { ERQ_NPDU,   "Echo Request" },
    { ERP_NPDU,   "Echo Response" },
    { 0,          NULL }
};

/* field position */

#define P_CLNP_PROTO_ID         0
#define P_CLNP_HDR_LEN          1
#define P_CLNP_VERS             2
#define P_CLNP_TTL              3
#define P_CLNP_TYPE             4
#define P_CLNP_SEGLEN           5
#define P_CLNP_CKSUM            7
#define P_CLNP_ADDRESS_PART     9

/* Segmentation part */

#define SEGMENTATION_PART_LEN   6

struct clnp_segment {
    gushort       cng_id;         /* data unit identifier */
    gushort       cng_off;        /* segment offset */
    gushort       cng_tot_len;    /* total length */
};

/* NSAP selector */

#define NSEL_NET                0x00
#define NSEL_NP                 0x20
#define NSEL_TP                 0x21

/* global variables */

/* List of dissectors to call for CLNP packets */
static heur_dissector_list_t clnp_heur_subdissector_list;

/*
 * Reassembly of CLNP.
 */
static reassembly_table clnp_reassembly_table;

/* options */
static guint tp_nsap_selector = NSEL_TP;
static gboolean always_decode_transport = FALSE;
static gboolean clnp_reassemble = TRUE;
gboolean clnp_decode_atn_options = FALSE;

/* function definitions */

/*
 *  CLNP part / main entry point
*/

static void
dissect_clnp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    proto_tree     *clnp_tree;
    proto_item     *ti, *ti_len = NULL, *ti_pdu_len = NULL, *ti_tot_len = NULL;
    guint8          cnf_proto_id;
    guint8          cnf_hdr_len;
    guint8          cnf_vers;
    guint8          cnf_ttl;
    guint8          cnf_type;
    char            flag_string[6+1];
    const char     *pdu_type_string;
    proto_tree     *type_tree;
    guint16         segment_length;
    guint16         du_id = 0;
    guint16         segment_offset = 0;
    guint16         total_length;
    guint16         cnf_cksum;
    cksum_status_t  cksum_status;
    int             offset;
    guchar          src_len, dst_len, nsel, opt_len = 0;
    const guint8   *dst_addr, *src_addr;
    guint           next_length;
    proto_tree     *discpdu_tree;
    gboolean        save_in_error_pkt;
    fragment_head  *fd_head;
    tvbuff_t       *next_tvb;
    gboolean        update_col_info = TRUE;
    gboolean        save_fragmented;
    heur_dtbl_entry_t *hdtbl_entry;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "CLNP");
    col_clear(pinfo->cinfo, COL_INFO);

    cnf_proto_id = tvb_get_guint8(tvb, P_CLNP_PROTO_ID);
    if (cnf_proto_id == NLPID_NULL) {
        col_set_str(pinfo->cinfo, COL_INFO, "Inactive subset");
        ti = proto_tree_add_item(tree, proto_clnp, tvb, P_CLNP_PROTO_ID, 1, ENC_NA);
        clnp_tree = proto_item_add_subtree(ti, ett_clnp);
        proto_tree_add_uint_format(clnp_tree, hf_clnp_id, tvb, P_CLNP_PROTO_ID, 1,
                cnf_proto_id, "Inactive subset");
        next_tvb = tvb_new_subset_remaining(tvb, 1);
        if (call_dissector(ositp_inactive_handle, next_tvb, pinfo, tree) == 0)
            call_dissector(data_handle,tvb, pinfo, tree);
        return;
    }

    /* return if version not known */
    cnf_vers = tvb_get_guint8(tvb, P_CLNP_VERS);
    if (cnf_vers != ISO8473_V1) {
        call_dissector(data_handle,tvb, pinfo, tree);
        return;
    }

    /* fixed part decoding */
    cnf_hdr_len = tvb_get_guint8(tvb, P_CLNP_HDR_LEN);

    ti = proto_tree_add_item(tree, proto_clnp, tvb, 0, cnf_hdr_len, ENC_NA);
    clnp_tree = proto_item_add_subtree(ti, ett_clnp);
    proto_tree_add_uint(clnp_tree, hf_clnp_id, tvb, P_CLNP_PROTO_ID, 1,
            cnf_proto_id);
    ti_len = proto_tree_add_uint(clnp_tree, hf_clnp_length, tvb, P_CLNP_HDR_LEN, 1,
            cnf_hdr_len);
    if (cnf_hdr_len < FIXED_PART_LEN) {
        /* Header length is less than the length of the fixed part of
           the header. */
        expert_add_info_format(pinfo, ti_len, &ei_clnp_length,
                "Header length value < minimum length %u",
                FIXED_PART_LEN);
        return;
    }
    proto_tree_add_uint(clnp_tree, hf_clnp_version, tvb, P_CLNP_VERS, 1,
                cnf_vers);
    cnf_ttl = tvb_get_guint8(tvb, P_CLNP_TTL);
    proto_tree_add_uint_format(clnp_tree, hf_clnp_ttl, tvb, P_CLNP_TTL, 1,
            cnf_ttl,
            "Holding Time : %u (%u.%u secs)",
            cnf_ttl, cnf_ttl / 2, (cnf_ttl % 2) * 5);
    cnf_type = tvb_get_guint8(tvb, P_CLNP_TYPE);
    pdu_type_string = val_to_str(cnf_type & CNF_TYPE, npdu_type_abbrev_vals,
            "Unknown (0x%02x)");
    flag_string[0] = '\0';
    if (cnf_type & CNF_SEG_OK)
        g_strlcat(flag_string, "S ", 7);
    if (cnf_type & CNF_MORE_SEGS)
        g_strlcat(flag_string, "M ", 7);
    if (cnf_type & CNF_ERR_OK)
        g_strlcat(flag_string, "E ", 7);
    ti = proto_tree_add_uint_format(clnp_tree, hf_clnp_type, tvb, P_CLNP_TYPE, 1,
            cnf_type,
            "PDU Type     : 0x%02x (%s%s)",
            cnf_type,
            flag_string,
            pdu_type_string);
    type_tree = proto_item_add_subtree(ti, ett_clnp_type);
    proto_tree_add_item(type_tree, hf_clnp_cnf_segmentation, tvb, P_CLNP_TYPE, 1, ENC_NA);
    proto_tree_add_item(type_tree, hf_clnp_cnf_more_segments, tvb, P_CLNP_TYPE, 1, ENC_NA);
    proto_tree_add_item(type_tree, hf_clnp_cnf_report_error, tvb, P_CLNP_TYPE, 1, ENC_NA);
    proto_tree_add_item(type_tree, hf_clnp_cnf_type, tvb, P_CLNP_TYPE, 1, ENC_BIG_ENDIAN);

    /* If we don't have the full header - i.e., not enough to see the
       segmentation part and determine whether this datagram is segmented
       or not - set the Info column now; we'll get an exception before
       we set it otherwise. */

    if (tvb_length(tvb) < cnf_hdr_len) {
        col_add_fstr(pinfo->cinfo, COL_INFO, "%s NPDU %s", pdu_type_string, flag_string);
    }

    segment_length = tvb_get_ntohs(tvb, P_CLNP_SEGLEN);
    ti_pdu_len = proto_tree_add_uint(clnp_tree, hf_clnp_pdu_length, tvb, P_CLNP_SEGLEN, 2,
            segment_length);
    if (segment_length < cnf_hdr_len) {
        /* Segment length is less than the header length. */
        expert_add_info_format(pinfo, ti_pdu_len, &ei_clnp_length,
                "PDU length < header length %u", cnf_hdr_len);
        return;
    }
    cnf_cksum = tvb_get_ntohs(tvb, P_CLNP_CKSUM);
    cksum_status = calc_checksum(tvb, 0, cnf_hdr_len, cnf_cksum);
    switch (cksum_status) {
        default:
            /*
             * No checksum present, or not enough of the header present to
             * checksum it.
             */
            proto_tree_add_uint(clnp_tree, hf_clnp_checksum, tvb,
                    P_CLNP_CKSUM, 2,
                    cnf_cksum);
            break;

        case CKSUM_OK:
            /*
             * Checksum is correct.
             */
            proto_tree_add_uint_format_value(clnp_tree, hf_clnp_checksum, tvb,
                    P_CLNP_CKSUM, 2,
                    cnf_cksum,
                    "0x%04x (correct)",
                    cnf_cksum);
            break;

        case CKSUM_NOT_OK:
            /*
             * Checksum is not correct.
             */
            proto_tree_add_uint_format_value(clnp_tree, hf_clnp_checksum, tvb,
                    P_CLNP_CKSUM, 2,
                    cnf_cksum,
                    "0x%04x (incorrect)",
                    cnf_cksum);
            break;
    }

    opt_len = cnf_hdr_len;
    opt_len -= FIXED_PART_LEN; /* Fixed part of Header */

    /* address part */

    offset = P_CLNP_ADDRESS_PART;
    if (opt_len < 1) {
        /* Header length is less than the minimum value in CLNP,
           including the destination address length. */
        expert_add_info_format(pinfo, ti_len, &ei_clnp_length,
                "Header length value < %u",
                FIXED_PART_LEN + 1);
        return;
    }
    dst_len  = tvb_get_guint8(tvb, offset);
    if (tree) {
        proto_tree_add_uint(clnp_tree, hf_clnp_dest_length, tvb, offset, 1,
                dst_len);
    }
    offset += 1;
    opt_len -= 1;

    if (opt_len < dst_len) {
        /* Header length is less than the minimum value,
           including the destination address length and the
           destination address. */
        expert_add_info_format(pinfo, ti_len, &ei_clnp_length,
                "Header length value < %u",
                FIXED_PART_LEN + 1 + dst_len);
        return;
    }
    dst_addr = tvb_get_ptr(tvb, offset, dst_len);
    nsel     = tvb_get_guint8(tvb, offset + dst_len - 1);
    SET_ADDRESS(&pinfo->net_dst, AT_OSI, dst_len, dst_addr);
    SET_ADDRESS(&pinfo->dst, AT_OSI, dst_len, dst_addr);
    proto_tree_add_bytes_format_value(clnp_tree, hf_clnp_dest, tvb, offset, dst_len,
            dst_addr,
            "%s",
            print_nsap_net(dst_addr, dst_len));
    offset += dst_len;
    opt_len -= dst_len;

    if (opt_len < 1) {
        /* Header length is less than the minimum value,
           including the destination address length, the
           destination address, and the source address length. */
        expert_add_info_format(pinfo, ti_len, &ei_clnp_length,
                "Header length value < %u",
                FIXED_PART_LEN + 1 + dst_len + 1);
        return;
    }
    src_len  = tvb_get_guint8(tvb, offset);
    if (tree) {
        proto_tree_add_uint(clnp_tree, hf_clnp_src_length, tvb,
                offset, 1, src_len);
    }
    offset += 1;
    opt_len -= 1;

    if (opt_len < src_len) {
        /* Header length is less than the minimum value,
           including the destination address length, the
           destination address, the source address length,
           and the source address. */
        expert_add_info_format(pinfo, ti_len, &ei_clnp_length,
                "Header length value < %u",
                FIXED_PART_LEN + 1 + dst_len + 1 + src_len);
        return;
    }
    src_addr = tvb_get_ptr(tvb, offset, src_len);
    SET_ADDRESS(&pinfo->net_src, AT_OSI, src_len, src_addr);
    SET_ADDRESS(&pinfo->src, AT_OSI, src_len, src_addr);
    proto_tree_add_bytes_format_value(clnp_tree, hf_clnp_src, tvb,
            offset, src_len,
            src_addr,
            "%s",
            print_nsap_net(src_addr, src_len));

    offset += src_len;
    opt_len -= src_len;

    /* Segmentation Part */

    if (cnf_type & CNF_SEG_OK) {
        if (opt_len < SEGMENTATION_PART_LEN) {
            /* Header length is less than the minimum value,
               including the destination address length, the
               destination address, the source address length,
               the source address, and the segmentation part. */
            expert_add_info_format(pinfo, ti_len, &ei_clnp_length,
                    "Header length value < %u",
                    FIXED_PART_LEN + 1 + dst_len + 1 + SEGMENTATION_PART_LEN);
            return;
        }

        du_id = tvb_get_ntohs(tvb, offset);
        proto_tree_add_item(clnp_tree, hf_clnp_data_unit_identifier, tvb, offset, 2, ENC_BIG_ENDIAN);
        segment_offset = tvb_get_ntohs(tvb, offset + 2);
        proto_tree_add_item(clnp_tree, hf_clnp_segment_offset, tvb, offset + 2 , 2, ENC_BIG_ENDIAN);
        total_length = tvb_get_ntohs(tvb, offset + 4);
        ti_tot_len = proto_tree_add_item(clnp_tree, hf_clnp_total_length, tvb, offset + 4 , 2, ENC_BIG_ENDIAN);
        if (total_length < segment_length) {
            /* Reassembled length is less than the length of this segment. */
            expert_add_info_format(pinfo, ti_tot_len, &ei_clnp_length,
                    "Total length < segment length %u", segment_length);
            return;
        }
        offset  += SEGMENTATION_PART_LEN;
        opt_len -= SEGMENTATION_PART_LEN;
    }

    dissect_osi_options(opt_len, tvb, offset, clnp_tree);

    offset += opt_len;

    /* If clnp_reassemble is on, this is a segment, we have all the
     * data in the segment, and the checksum is valid, then just add the
     * segment to the hashtable.
     */
    save_fragmented = pinfo->fragmented;
    if (clnp_reassemble && (cnf_type & CNF_SEG_OK) &&
            ((cnf_type & CNF_MORE_SEGS) || segment_offset != 0) &&
            tvb_bytes_exist(tvb, offset, segment_length - cnf_hdr_len) &&
            segment_length > cnf_hdr_len &&
            cksum_status != CKSUM_NOT_OK) {
        fd_head = fragment_add_check(&clnp_reassembly_table,
                tvb, offset, pinfo, du_id, NULL,
                segment_offset, segment_length - cnf_hdr_len,
                cnf_type & CNF_MORE_SEGS);

        next_tvb = process_reassembled_data(tvb, offset, pinfo, "Reassembled CLNP",
                fd_head, &clnp_frag_items, &update_col_info, clnp_tree);
    } else {
        /* If this is the first segment, dissect its contents, otherwise
           just show it as a segment.

           XXX - if we eventually don't save the reassembled contents of all
           segmented datagrams, we may want to always reassemble. */
        if ((cnf_type & CNF_SEG_OK) && segment_offset != 0) {
            /* Not the first segment - don't dissect it. */
            next_tvb = NULL;
        } else {
            /* First segment, or not segmented.  Dissect what we have here. */

            /* Get a tvbuff for the payload.  Set its length to the segment
               length, and flag it as a fragment, so going past the end
               reports FragmentBoundsError, i.e. "there's data missing
               because this isn't reassembled", not ReportedBoundsError,
               i.e. "the dissector ran past the end of the packet, so the
               packet must not have been constructed properly". */
            next_tvb = tvb_new_subset_length(tvb, offset, segment_length - cnf_hdr_len);
            tvb_set_fragment(next_tvb);

            /*
             * If this is the first segment, but not the only segment,
             * tell the next protocol that.
             */
            if ((cnf_type & (CNF_SEG_OK|CNF_MORE_SEGS)) == (CNF_SEG_OK|CNF_MORE_SEGS))
                pinfo->fragmented = TRUE;
            else
                pinfo->fragmented = FALSE;
        }
    }

    if (next_tvb == NULL) {
        /* Just show this as a segment. */
        col_add_fstr(pinfo->cinfo, COL_INFO, "Fragmented %s NPDU %s(off=%u)",
                pdu_type_string, flag_string, segment_offset);

        /* As we haven't reassembled anything, we haven't changed "pi", so
           we don't have to restore it. */
        call_dissector(data_handle, tvb_new_subset_remaining(tvb, offset), pinfo,
                tree);
        pinfo->fragmented = save_fragmented;
        return;
    }

    if (tvb_offset_exists(tvb, offset)) {
        switch (cnf_type & CNF_TYPE) {

            case DT_NPDU:
            case MD_NPDU:
                /* Continue with COTP if any data.
                   XXX - if this isn't the first Derived PDU of a segmented Initial
                   PDU, skip that? */

                if (nsel==NSEL_NET && tvb_get_guint8(next_tvb, 0)==NLPID_ISO10747_IDRP) {
                    if(call_dissector(idrp_handle, next_tvb, pinfo, tree) != 0) {
                        pinfo->fragmented = save_fragmented;
                        return;
                    }
                }
                if (nsel == (guchar)tp_nsap_selector || always_decode_transport) {
                    if (call_dissector(ositp_handle, next_tvb, pinfo, tree) != 0) {
                        pinfo->fragmented = save_fragmented;
                        return;       /* yes, it appears to be COTP or CLTP */
                    }
                }
                if (dissector_try_heuristic(clnp_heur_subdissector_list, next_tvb,
                            pinfo, tree, &hdtbl_entry, NULL)) {
                    pinfo->fragmented = save_fragmented;
                    return;       /* yes, it appears to be one of the protocols in the heuristic list */
                }

                break;

            case ER_NPDU:
                /* The payload is the header and "none, some, or all of the data
                   part of the discarded PDU", i.e. it's like an ICMP error;
                   dissect it as a CLNP PDU. */

                col_add_fstr(pinfo->cinfo, COL_INFO, "%s NPDU %s", pdu_type_string, flag_string);
                next_length = tvb_length_remaining(tvb, offset);
                if (next_length != 0) {
                    /* We have payload; dissect it. */
                    discpdu_tree = proto_tree_add_subtree(clnp_tree, tvb, offset, next_length,
                            ett_clnp_disc_pdu, NULL, "Discarded PDU");

                    /* Save the current value of the "we're inside an error packet"
                       flag, and set that flag; subdissectors may treat packets
                       that are the payload of error packets differently from
                       "real" packets. */
                    save_in_error_pkt = pinfo->flags.in_error_pkt;
                    pinfo->flags.in_error_pkt = TRUE;

                    call_dissector(clnp_handle, next_tvb, pinfo, discpdu_tree);

                    /* Restore the "we're inside an error packet" flag. */
                    pinfo->flags.in_error_pkt = save_in_error_pkt;
                }
                pinfo->fragmented = save_fragmented;
                return;   /* we're done with this PDU */

            case ERQ_NPDU:
            case ERP_NPDU:
                /* XXX - dissect this */
                break;
        }
    }
    col_add_fstr(pinfo->cinfo, COL_INFO, "%s NPDU %s", pdu_type_string, flag_string);
    call_dissector(data_handle,next_tvb, pinfo, tree);
    pinfo->fragmented = save_fragmented;
} /* dissect_clnp */

static void
clnp_reassemble_init(void)
{
    reassembly_table_init(&clnp_reassembly_table,
            &addresses_reassembly_table_functions);
}

void
proto_register_clnp(void)
{
    static hf_register_info hf[] = {
        { &hf_clnp_id,
            { "Network Layer Protocol Identifier", "clnp.nlpi", FT_UINT8, BASE_HEX,
                VALS(nlpid_vals), 0x0, NULL, HFILL }},

        { &hf_clnp_length,
            { "HDR Length", "clnp.len",          FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_version,
            { "Version", "clnp.version",  FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_ttl,
            { "Holding Time", "clnp.ttl",        FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_type,
            { "PDU Type", "clnp.type",     FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_cnf_segmentation,
            { "Segmentation permitted", "clnp.cnf.segmentation", FT_BOOLEAN, 8, TFS(&tfs_yes_no), CNF_SEG_OK, NULL, HFILL }},

        { &hf_clnp_cnf_more_segments,
            { "More segments", "clnp.cnf.more_segments", FT_BOOLEAN, 8, TFS(&tfs_yes_no), CNF_MORE_SEGS, NULL, HFILL }},

        { &hf_clnp_cnf_report_error,
            { "Report error if PDU discarded", "clnp.cnf.report_error", FT_BOOLEAN, 8, TFS(&tfs_yes_no), CNF_ERR_OK, NULL, HFILL }},

        { &hf_clnp_cnf_type,
            { "Type", "clnp.cnf.type", FT_UINT8, BASE_DEC, VALS(npdu_type_vals), CNF_TYPE, NULL, HFILL }},

        { &hf_clnp_pdu_length,
            { "PDU length", "clnp.pdu.len",  FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_data_unit_identifier,
            { "Data unit identifier", "clnp.data_unit_identifier",  FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_segment_offset,
            { "Segment offset", "clnp.segment_offset",  FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_total_length,
            { "Total length", "clnp.total_length",  FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_checksum,
            { "Checksum", "clnp.checksum", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_dest_length,
            { "DAL", "clnp.dsap.len", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_dest,
            { "DA", "clnp.dsap",     FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_src_length,
            { "SAL", "clnp.ssap.len", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_src,
            { "SA", "clnp.ssap",     FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_atntt,
            { "ATN traffic type", "clnp.atn.tt",     FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_atnsc,
            { "ATN security classification", "clnp.atn.sc",     FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},

        { &hf_clnp_segment_overlap,
            { "Segment overlap", "clnp.segment.overlap", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
                "Segment overlaps with other segments", HFILL }},

        { &hf_clnp_segment_overlap_conflict,
            { "Conflicting data in segment overlap", "clnp.segment.overlap.conflict", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
                "Overlapping segments contained conflicting data", HFILL }},

        { &hf_clnp_segment_multiple_tails,
            { "Multiple tail segments found", "clnp.segment.multipletails", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
                "Several tails were found when reassembling the packet", HFILL }},

        { &hf_clnp_segment_too_long_segment,
            { "Segment too long", "clnp.segment.toolongsegment", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
                "Segment contained data past end of packet", HFILL }},

        { &hf_clnp_segment_error,
            { "Reassembly error", "clnp.segment.error", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
                "Reassembly error due to illegal segments", HFILL }},

        { &hf_clnp_segment_count,
            { "Segment count", "clnp.segment.count", FT_UINT32, BASE_DEC, NULL, 0x0,
                NULL, HFILL }},

        { &hf_clnp_segment,
            { "CLNP Segment", "clnp.segment", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
                NULL, HFILL }},

        { &hf_clnp_segments,
            { "CLNP Segments", "clnp.segments", FT_NONE, BASE_NONE, NULL, 0x0,
                NULL, HFILL }},

        { &hf_clnp_reassembled_in,
            { "Reassembled CLNP in frame", "clnp.reassembled_in", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
                "This CLNP packet is reassembled in this frame", HFILL }},

        { &hf_clnp_reassembled_length,
            { "Reassembled CLNP length", "clnp.reassembled.length", FT_UINT32, BASE_DEC, NULL, 0x0,
                "The total length of the reassembled payload", HFILL }}
    };
    static gint *ett[] = {
        &ett_clnp,
        &ett_clnp_type,
        &ett_clnp_segments,
        &ett_clnp_segment,
        &ett_clnp_disc_pdu,
    };

    static ei_register_info ei[] = {
        { &ei_clnp_length, { "clnp.len.bad", PI_MALFORMED, PI_ERROR, "Header length value bad", EXPFILL }},
    };

    module_t *clnp_module;
    expert_module_t* expert_clnp;

    proto_clnp = proto_register_protocol(PROTO_STRING_CLNP, "CLNP", "clnp");
    proto_register_field_array(proto_clnp, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
    expert_clnp = expert_register_protocol(proto_clnp);
    expert_register_field_array(expert_clnp, ei, array_length(ei));
    register_dissector("clnp", dissect_clnp, proto_clnp);
    clnp_heur_subdissector_list = register_heur_dissector_list("clnp");
    register_init_routine(clnp_reassemble_init);

    clnp_module = prefs_register_protocol(proto_clnp, NULL);
    prefs_register_uint_preference(clnp_module, "tp_nsap_selector",
            "NSAP selector for Transport Protocol (last byte in hex)",
            "NSAP selector for Transport Protocol (last byte in hex)",
            16, &tp_nsap_selector);
    prefs_register_bool_preference(clnp_module, "always_decode_transport",
            "Always try to decode NSDU as transport PDUs",
            "Always try to decode NSDU as transport PDUs",
            &always_decode_transport);
    prefs_register_bool_preference(clnp_module, "reassemble",
            "Reassemble segmented CLNP datagrams",
            "Whether segmented CLNP datagrams should be reassembled",
            &clnp_reassemble);
    prefs_register_bool_preference(clnp_module, "decode_atn_options",
            "Decode ATN security label",
            "Whether ATN security label should be decoded",
            &clnp_decode_atn_options);
}

void
proto_reg_handoff_clnp(void)
{
    ositp_handle = find_dissector("ositp");
    ositp_inactive_handle = find_dissector("ositp_inactive");
    idrp_handle = find_dissector("idrp");
    data_handle = find_dissector("data");

    clnp_handle = create_dissector_handle(dissect_clnp, proto_clnp);
    dissector_add_uint("osinl.incl", NLPID_ISO8473_CLNP, clnp_handle);
    dissector_add_uint("osinl.incl", NLPID_NULL, clnp_handle); /* Inactive subset */
    dissector_add_uint("x.25.spi", NLPID_ISO8473_CLNP, clnp_handle);
}

/*
 * Editor modelines  -  http://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:
 */