summaryrefslogtreecommitdiff
path: root/print-sctp.c
blob: b009e051fc5c289e90a7ee38174b2835d7214067 (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
/* Copyright (c) 2001 NETLAB, Temple University
 * Copyright (c) 2001 Protocol Engineering Lab, University of Delaware
 *
 * Jerry Heinz <gheinz@astro.temple.edu>
 * John Fiore <jfiore@joda.cis.temple.edu>
 * Armando L. Caro Jr. <acaro@cis.udel.edu>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#define NETDISSECT_REWORKED
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <tcpdump-stdinc.h>

#include "interface.h"
#include "addrtoname.h"
#include "extract.h"			/* must come after interface.h */
#include "ip.h"
#ifdef INET6
#include "ip6.h"
#endif

/* Definitions from:
 *
 * SCTP reference Implementation Copyright (C) 1999 Cisco And Motorola
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of Cisco nor of Motorola may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the SCTP reference Implementation
 *
 *
 * Please send any bug reports or fixes you make to one of the following email
 * addresses:
 *
 * rstewar1@email.mot.com
 * kmorneau@cisco.com
 * qxie1@email.mot.com
 *
 * Any bugs reported given to us we will try to fix... any fixes shared will
 * be incorperated into the next SCTP release.
 */

/* The valid defines for all message
 * types know to SCTP. 0 is reserved
 */
#define SCTP_DATA		0x00
#define SCTP_INITIATION		0x01
#define SCTP_INITIATION_ACK	0x02
#define SCTP_SELECTIVE_ACK	0x03
#define SCTP_HEARTBEAT_REQUEST	0x04
#define SCTP_HEARTBEAT_ACK	0x05
#define SCTP_ABORT_ASSOCIATION	0x06
#define SCTP_SHUTDOWN		0x07
#define SCTP_SHUTDOWN_ACK	0x08
#define SCTP_OPERATION_ERR	0x09
#define SCTP_COOKIE_ECHO	0x0a
#define SCTP_COOKIE_ACK         0x0b
#define SCTP_ECN_ECHO		0x0c
#define SCTP_ECN_CWR		0x0d
#define SCTP_SHUTDOWN_COMPLETE	0x0e
#define SCTP_FORWARD_CUM_TSN    0xc0
#define SCTP_RELIABLE_CNTL      0xc1
#define SCTP_RELIABLE_CNTL_ACK  0xc2

/* Data Chuck Specific Flags */
#define SCTP_DATA_FRAG_MASK	0x03
#define SCTP_DATA_MIDDLE_FRAG	0x00
#define SCTP_DATA_LAST_FRAG	0x01
#define SCTP_DATA_FIRST_FRAG	0x02
#define SCTP_DATA_NOT_FRAG	0x03
#define SCTP_DATA_UNORDERED	0x04

#define SCTP_ADDRMAX 60

#define CHAN_HP 6704
#define CHAN_MP 6705
#define CHAN_LP 6706

/* the sctp common header */

struct sctpHeader{
  u_int16_t source;
  u_int16_t destination;
  u_int32_t verificationTag;
  u_int32_t adler32;
};

/* various descriptor parsers */

struct sctpChunkDesc{
  u_int8_t chunkID;
  u_int8_t chunkFlg;
  u_int16_t chunkLength;
};

struct sctpParamDesc{
  u_int16_t paramType;
  u_int16_t paramLength;
};


struct sctpRelChunkDesc{
  struct sctpChunkDesc chk;
  u_int32_t serialNumber;
};

struct sctpVendorSpecificParam {
  struct sctpParamDesc p;  /* type must be 0xfffe */
  u_int32_t vendorId;	   /* vendor ID from RFC 1700 */
  u_int16_t vendorSpecificType;
  u_int16_t vendorSpecificLen;
};


/* Structures for the control parts */



/* Sctp association init request/ack */

/* this is used for init ack, too */
struct sctpInitiation{
  u_int32_t initTag;		/* tag of mine */
  u_int32_t rcvWindowCredit;	/* rwnd */
  u_int16_t NumPreopenStreams;	/* OS */
  u_int16_t MaxInboundStreams;     /* MIS */
  u_int32_t initialTSN;
  /* optional param's follow in sctpParamDesc form */
};

struct sctpV4IpAddress{
  struct sctpParamDesc p;	/* type is set to SCTP_IPV4_PARAM_TYPE, len=10 */
  u_int32_t  ipAddress;
};


struct sctpV6IpAddress{
  struct sctpParamDesc p;	/* type is set to SCTP_IPV6_PARAM_TYPE, len=22 */
  u_int8_t  ipAddress[16];
};

struct sctpDNSName{
  struct sctpParamDesc param;
  u_int8_t name[1];
};


struct sctpCookiePreserve{
  struct sctpParamDesc p;	/* type is set to SCTP_COOKIE_PRESERVE, len=8 */
  u_int32_t extraTime;
};


struct sctpTimeStamp{
  u_int32_t ts_sec;
  u_int32_t ts_usec;
};

/* wire structure of my cookie */
struct cookieMessage{
  u_int32_t TieTag_curTag;		/* copied from assoc if present */
  u_int32_t TieTag_hisTag; 		/* copied from assoc if present */
  int32_t cookieLife;			/* life I will award this cookie */
  struct sctpTimeStamp timeEnteringState; /* the time I built cookie */
  struct sctpInitiation initAckISent;	/* the INIT-ACK that I sent to my peer */
  u_int32_t addressWhereISent[4];	/* I make this 4 ints so I get 128bits for future */
  int32_t addrtype;			/* address type */
  u_int16_t locScope;			/* V6 local scope flag */
  u_int16_t siteScope;			/* V6 site scope flag */
  /* at the end is tacked on the INIT chunk sent in
   * its entirety and of course our
   * signature.
   */
};


/* this guy is for use when
 * I have a initiate message gloming the
 * things together.

 */
struct sctpUnifiedInit{
  struct sctpChunkDesc uh;
  struct sctpInitiation initm;
};

struct sctpSendableInit{
  struct sctpHeader mh;
  struct sctpUnifiedInit msg;
};


/* Selective Acknowledgement
 * has the following structure with
 * a optional ammount of trailing int's
 * on the last part (based on the numberOfDesc
 * field).
 */

struct sctpSelectiveAck{
  u_int32_t highestConseqTSN;
  u_int32_t updatedRwnd;
  u_int16_t numberOfdesc;
  u_int16_t numDupTsns;
};

struct sctpSelectiveFrag{
  u_int16_t fragmentStart;
  u_int16_t fragmentEnd;
};


struct sctpUnifiedSack{
  struct sctpChunkDesc uh;
  struct sctpSelectiveAck sack;
};

/* for both RTT request/response the
 * following is sent
 */

struct sctpHBrequest {
  u_int32_t time_value_1;
  u_int32_t time_value_2;
};

/* here is what I read and respond with to. */
struct sctpHBunified{
  struct sctpChunkDesc hdr;
  struct sctpParamDesc hb;
};


/* here is what I send */
struct sctpHBsender{
  struct sctpChunkDesc hdr;
  struct sctpParamDesc hb;
  struct sctpHBrequest rtt;
  int8_t addrFmt[SCTP_ADDRMAX];
  u_int16_t userreq;
};



/* for the abort and shutdown ACK
 * we must carry the init tag in the common header. Just the
 * common header is all that is needed with a chunk descriptor.
 */
struct sctpUnifiedAbort{
  struct sctpChunkDesc uh;
};

struct sctpUnifiedAbortLight{
  struct sctpHeader mh;
  struct sctpChunkDesc uh;
};

struct sctpUnifiedAbortHeavy{
  struct sctpHeader mh;
  struct sctpChunkDesc uh;
  u_int16_t causeCode;
  u_int16_t causeLen;
};

/* For the graceful shutdown we must carry
 * the tag (in common header)  and the highest consequitive acking value
 */
struct sctpShutdown {
  u_int32_t TSN_Seen;
};

struct sctpUnifiedShutdown{
  struct sctpChunkDesc uh;
  struct sctpShutdown shut;
};

/* in the unified message we add the trailing
 * stream id since it is the only message
 * that is defined as a operation error.
 */
struct sctpOpErrorCause{
  u_int16_t cause;
  u_int16_t causeLen;
};

struct sctpUnifiedOpError{
  struct sctpChunkDesc uh;
  struct sctpOpErrorCause c;
};

struct sctpUnifiedStreamError{
  struct sctpHeader mh;
  struct sctpChunkDesc uh;
  struct sctpOpErrorCause c;
  u_int16_t strmNum;
  u_int16_t reserved;
};

struct staleCookieMsg{
  struct sctpHeader mh;
  struct sctpChunkDesc uh;
  struct sctpOpErrorCause c;
  u_int32_t moretime;
};

/* the following is used in all sends
 * where nothing is needed except the
 * chunk/type i.e. shutdownAck Abort */

struct sctpUnifiedSingleMsg{
  struct sctpHeader mh;
  struct sctpChunkDesc uh;
};

struct sctpDataPart{
  u_int32_t TSN;
  u_int16_t streamId;
  u_int16_t sequence;
  u_int32_t payloadtype;
};

struct sctpUnifiedDatagram{
  struct sctpChunkDesc uh;
  struct sctpDataPart dp;
};

struct sctpECN_echo{
  struct sctpChunkDesc uh;
  u_int32_t Lowest_TSN;
};


struct sctpCWR{
  struct sctpChunkDesc uh;
  u_int32_t TSN_reduced_at;
};

static const struct tok ForCES_channels[] = {
	{ CHAN_HP, "ForCES HP" },
	{ CHAN_MP, "ForCES MP" },
	{ CHAN_LP, "ForCES LP" },
	{ 0, NULL }
};

static inline int isForCES_port(u_short Port)
{
	if (Port == CHAN_HP)
		return 1;
	if (Port == CHAN_MP)
		return 1;
	if (Port == CHAN_LP)
		return 1;

	return 0;
}

void sctp_print(netdissect_options *ndo,
                const u_char *bp,        /* beginning of sctp packet */
                const u_char *bp2,       /* beginning of enclosing */
                u_int sctpPacketLength)  /* ip packet */
{
  const struct sctpHeader *sctpPktHdr;
  const struct ip *ip;
#ifdef INET6
  const struct ip6_hdr *ip6;
#endif
  const void *endPacketPtr;
  u_short sourcePort, destPort;
  int chunkCount;
  const struct sctpChunkDesc *chunkDescPtr;
  const void *nextChunk;
  const char *sep;
  int isforces = 0;


  sctpPktHdr = (const struct sctpHeader*) bp;
  endPacketPtr = (const u_char*)sctpPktHdr+sctpPacketLength;

  if( (u_long) endPacketPtr > (u_long) ndo->ndo_snapend)
    endPacketPtr = (const void *) ndo->ndo_snapend;
  ip = (struct ip *)bp2;
#ifdef INET6
  if (IP_V(ip) == 6)
    ip6 = (const struct ip6_hdr *)bp2;
  else
    ip6 = NULL;
#endif /*INET6*/
  ND_TCHECK(*sctpPktHdr);

  if (sctpPacketLength < sizeof(struct sctpHeader))
    {
      ND_PRINT((ndo, "truncated-sctp - %ld bytes missing!",
		   (long)sctpPacketLength-sizeof(struct sctpHeader)));
      return;
    }

  /*    sctpPacketLength -= sizeof(struct sctpHeader);  packet length  */
  /*  			      is now only as long as the payload  */

  sourcePort = EXTRACT_16BITS(&sctpPktHdr->source);
  destPort = EXTRACT_16BITS(&sctpPktHdr->destination);

#ifdef INET6
  if (ip6) {
    ND_PRINT((ndo, "%s.%d > %s.%d: sctp",
      ip6addr_string(&ip6->ip6_src),
      sourcePort,
      ip6addr_string(&ip6->ip6_dst),
      destPort));
  } else
#endif /*INET6*/
  {
    ND_PRINT((ndo, "%s.%d > %s.%d: sctp",
      ipaddr_string(&ip->ip_src),
      sourcePort,
      ipaddr_string(&ip->ip_dst),
      destPort));
  }

  if (isForCES_port(sourcePort)) {
         ND_PRINT((ndo, "[%s]", tok2str(ForCES_channels, NULL, sourcePort)));
         isforces = 1;
  }
  if (isForCES_port(destPort)) {
         ND_PRINT((ndo, "[%s]", tok2str(ForCES_channels, NULL, destPort)));
         isforces = 1;
  }

  if (ndo->ndo_vflag >= 2)
    sep = "\n\t";
  else
    sep = " (";
  /* cycle through all chunks, printing information on each one */
  for (chunkCount = 0,
	 chunkDescPtr = (const struct sctpChunkDesc *)
	    ((const u_char*) sctpPktHdr + sizeof(struct sctpHeader));
       chunkDescPtr != NULL &&
	 ( (const void *)
	    ((const u_char *) chunkDescPtr + sizeof(struct sctpChunkDesc))
	   <= endPacketPtr);

       chunkDescPtr = (const struct sctpChunkDesc *) nextChunk, chunkCount++)
    {
      u_int16_t chunkLength;
      const u_char *chunkEnd;
      u_int16_t align;

      ND_TCHECK(*chunkDescPtr);
      chunkLength = EXTRACT_16BITS(&chunkDescPtr->chunkLength);
      if (chunkLength < sizeof(*chunkDescPtr)) {
        ND_PRINT((ndo, "%s%d) [Bad chunk length %u]", sep, chunkCount+1, chunkLength));
        break;
      }

      ND_TCHECK2(*((u_int8_t *)chunkDescPtr), chunkLength);
      chunkEnd = ((const u_char*)chunkDescPtr + chunkLength);

      align=chunkLength % 4;
      if (align != 0)
	align = 4 - align;

      nextChunk = (const void *) (chunkEnd + align);

      ND_PRINT((ndo, "%s%d) ", sep, chunkCount+1));
      switch (chunkDescPtr->chunkID)
	{
	case SCTP_DATA :
	  {
	    const struct sctpDataPart *dataHdrPtr;

	    ND_PRINT((ndo, "[DATA] "));

	    if ((chunkDescPtr->chunkFlg & SCTP_DATA_UNORDERED)
		== SCTP_DATA_UNORDERED)
	      ND_PRINT((ndo, "(U)"));

	    if ((chunkDescPtr->chunkFlg & SCTP_DATA_FIRST_FRAG)
		== SCTP_DATA_FIRST_FRAG)
	      ND_PRINT((ndo, "(B)"));

	    if ((chunkDescPtr->chunkFlg & SCTP_DATA_LAST_FRAG)
		== SCTP_DATA_LAST_FRAG)
	      ND_PRINT((ndo, "(E)"));

	    if( ((chunkDescPtr->chunkFlg & SCTP_DATA_UNORDERED)
		 == SCTP_DATA_UNORDERED)
		||
		((chunkDescPtr->chunkFlg & SCTP_DATA_FIRST_FRAG)
		 == SCTP_DATA_FIRST_FRAG)
		||
		((chunkDescPtr->chunkFlg & SCTP_DATA_LAST_FRAG)
		 == SCTP_DATA_LAST_FRAG) )
	      ND_PRINT((ndo, " "));

	    dataHdrPtr=(const struct sctpDataPart*)(chunkDescPtr+1);

	    ND_PRINT((ndo, "[TSN: %u] ", EXTRACT_32BITS(&dataHdrPtr->TSN)));
	    ND_PRINT((ndo, "[SID: %u] ", EXTRACT_16BITS(&dataHdrPtr->streamId)));
	    ND_PRINT((ndo, "[SSEQ %u] ", EXTRACT_16BITS(&dataHdrPtr->sequence)));
	    ND_PRINT((ndo, "[PPID 0x%x] ", EXTRACT_32BITS(&dataHdrPtr->payloadtype)));
	    if (isforces) {
		const u_char *payloadPtr;
		u_int chunksize = sizeof(struct sctpDataPart)+
			          sizeof(struct sctpChunkDesc);
		payloadPtr = (const u_char *) (dataHdrPtr + 1);
		if (EXTRACT_16BITS(&chunkDescPtr->chunkLength) <
			sizeof(struct sctpDataPart)+
			sizeof(struct sctpChunkDesc)+1) {
		/* Less than 1 byte of chunk payload */
			ND_PRINT((ndo, "bogus ForCES chunk length %u]",
			    EXTRACT_16BITS(&chunkDescPtr->chunkLength)));
			return;
		}

		forces_print(ndo, payloadPtr, EXTRACT_16BITS(&chunkDescPtr->chunkLength)- chunksize);
	   } else if (ndo->ndo_vflag >= 2) {	/* if verbose output is specified */
					/* at the command line */
		const u_char *payloadPtr;

		ND_PRINT((ndo, "[Payload"));

		if (!ndo->ndo_suppress_default_print) {
			payloadPtr = (const u_char *) (++dataHdrPtr);
			ND_PRINT((ndo, ":"));
			if (EXTRACT_16BITS(&chunkDescPtr->chunkLength) <
			    sizeof(struct sctpDataPart)+
			    sizeof(struct sctpChunkDesc)+1) {
				/* Less than 1 byte of chunk payload */
				ND_PRINT((ndo, "bogus chunk length %u]",
				    EXTRACT_16BITS(&chunkDescPtr->chunkLength)));
				return;
			}
			default_print(payloadPtr,
			      EXTRACT_16BITS(&chunkDescPtr->chunkLength) -
			      (sizeof(struct sctpDataPart)+
			      sizeof(struct sctpChunkDesc)));
		} else
			ND_PRINT((ndo, "]"));
	      }
	    break;
	  }
	case SCTP_INITIATION :
	  {
	    const struct sctpInitiation *init;

	    ND_PRINT((ndo, "[INIT] "));
	    init=(const struct sctpInitiation*)(chunkDescPtr+1);
	    ND_PRINT((ndo, "[init tag: %u] ", EXTRACT_32BITS(&init->initTag)));
	    ND_PRINT((ndo, "[rwnd: %u] ", EXTRACT_32BITS(&init->rcvWindowCredit)));
	    ND_PRINT((ndo, "[OS: %u] ", EXTRACT_16BITS(&init->NumPreopenStreams)));
	    ND_PRINT((ndo, "[MIS: %u] ", EXTRACT_16BITS(&init->MaxInboundStreams)));
	    ND_PRINT((ndo, "[init TSN: %u] ", EXTRACT_32BITS(&init->initialTSN)));

#if(0) /* ALC you can add code for optional params here */
	    if( (init+1) < chunkEnd )
	      ND_PRINT((ndo, " @@@@@ UNFINISHED @@@@@@%s\n",
		     "Optional params present, but not printed."));
#endif
	    break;
	  }
	case SCTP_INITIATION_ACK :
	  {
	    const struct sctpInitiation *init;

	    ND_PRINT((ndo, "[INIT ACK] "));
	    init=(const struct sctpInitiation*)(chunkDescPtr+1);
	    ND_PRINT((ndo, "[init tag: %u] ", EXTRACT_32BITS(&init->initTag)));
	    ND_PRINT((ndo, "[rwnd: %u] ", EXTRACT_32BITS(&init->rcvWindowCredit)));
	    ND_PRINT((ndo, "[OS: %u] ", EXTRACT_16BITS(&init->NumPreopenStreams)));
	    ND_PRINT((ndo, "[MIS: %u] ", EXTRACT_16BITS(&init->MaxInboundStreams)));
	    ND_PRINT((ndo, "[init TSN: %u] ", EXTRACT_32BITS(&init->initialTSN)));

#if(0) /* ALC you can add code for optional params here */
	    if( (init+1) < chunkEnd )
	      ND_PRINT((ndo, " @@@@@ UNFINISHED @@@@@@%s\n",
		     "Optional params present, but not printed."));
#endif
	    break;
	  }
	case SCTP_SELECTIVE_ACK:
	  {
	    const struct sctpSelectiveAck *sack;
	    const struct sctpSelectiveFrag *frag;
	    int fragNo, tsnNo;
	    const u_char *dupTSN;

	    ND_PRINT((ndo, "[SACK] "));
	    sack=(const struct sctpSelectiveAck*)(chunkDescPtr+1);
	    ND_PRINT((ndo, "[cum ack %u] ", EXTRACT_32BITS(&sack->highestConseqTSN)));
	    ND_PRINT((ndo, "[a_rwnd %u] ", EXTRACT_32BITS(&sack->updatedRwnd)));
	    ND_PRINT((ndo, "[#gap acks %u] ", EXTRACT_16BITS(&sack->numberOfdesc)));
	    ND_PRINT((ndo, "[#dup tsns %u] ", EXTRACT_16BITS(&sack->numDupTsns)));


	    /* print gaps */
	    for (frag = ( (const struct sctpSelectiveFrag *)
			  ((const struct sctpSelectiveAck *) sack+1)),
		   fragNo=0;
		 (const void *)frag < nextChunk && fragNo < EXTRACT_16BITS(&sack->numberOfdesc);
		 frag++, fragNo++)
	      ND_PRINT((ndo, "\n\t\t[gap ack block #%d: start = %u, end = %u] ",
		     fragNo+1,
		     EXTRACT_32BITS(&sack->highestConseqTSN) + EXTRACT_16BITS(&frag->fragmentStart),
		     EXTRACT_32BITS(&sack->highestConseqTSN) + EXTRACT_16BITS(&frag->fragmentEnd)));


	    /* print duplicate TSNs */
	    for (dupTSN = (const u_char *)frag, tsnNo=0;
		 (const void *) dupTSN < nextChunk && tsnNo<EXTRACT_16BITS(&sack->numDupTsns);
		 dupTSN += 4, tsnNo++)
	      ND_PRINT((ndo, "\n\t\t[dup TSN #%u: %u] ", tsnNo+1,
	          EXTRACT_32BITS(dupTSN)));

	    break;
	  }
	case SCTP_HEARTBEAT_REQUEST :
	  ND_PRINT((ndo, "[HB REQ] "));
	  break;
	case SCTP_HEARTBEAT_ACK :
	  ND_PRINT((ndo, "[HB ACK] "));
	  break;
	case SCTP_ABORT_ASSOCIATION :
	  ND_PRINT((ndo, "[ABORT] "));
	  break;
	case SCTP_SHUTDOWN :
	  ND_PRINT((ndo, "[SHUTDOWN] "));
	  break;
	case SCTP_SHUTDOWN_ACK :
	  ND_PRINT((ndo, "[SHUTDOWN ACK] "));
	  break;
	case SCTP_OPERATION_ERR :
	  ND_PRINT((ndo, "[OP ERR] "));
	  break;
	case SCTP_COOKIE_ECHO :
	  ND_PRINT((ndo, "[COOKIE ECHO] "));
	  break;
	case SCTP_COOKIE_ACK :
	  ND_PRINT((ndo, "[COOKIE ACK] "));
	  break;
	case SCTP_ECN_ECHO :
	  ND_PRINT((ndo, "[ECN ECHO] "));
	  break;
	case SCTP_ECN_CWR :
	  ND_PRINT((ndo, "[ECN CWR] "));
	  break;
	case SCTP_SHUTDOWN_COMPLETE :
	  ND_PRINT((ndo, "[SHUTDOWN COMPLETE] "));
	  break;
	case SCTP_FORWARD_CUM_TSN :
	  ND_PRINT((ndo, "[FOR CUM TSN] "));
	  break;
	case SCTP_RELIABLE_CNTL :
	  ND_PRINT((ndo, "[REL CTRL] "));
	  break;
	case SCTP_RELIABLE_CNTL_ACK :
	  ND_PRINT((ndo, "[REL CTRL ACK] "));
	  break;
	default :
	  ND_PRINT((ndo, "[Unknown chunk type: 0x%x]", chunkDescPtr->chunkID));
	  return;
	}

	if (ndo->ndo_vflag < 2)
	  sep = ", (";
    }
    return;

trunc:
    ND_PRINT((ndo, "[|sctp]"));
}