• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /* Copyright (c) 2001 NETLAB, Temple University
2  * Copyright (c) 2001 Protocol Engineering Lab, University of Delaware
3  *
4  * Jerry Heinz <gheinz@astro.temple.edu>
5  * John Fiore <jfiore@joda.cis.temple.edu>
6  * Armando L. Caro Jr. <acaro@cis.udel.edu>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * 3. Neither the name of the University nor of the Laboratory may be used
20  *    to endorse or promote products derived from this software without
21  *    specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #define NETDISSECT_REWORKED
37 #ifdef HAVE_CONFIG_H
38 #include "config.h"
39 #endif
40 
41 #include <tcpdump-stdinc.h>
42 
43 #include "interface.h"
44 #include "addrtoname.h"
45 #include "extract.h"			/* must come after interface.h */
46 #include "ip.h"
47 #ifdef INET6
48 #include "ip6.h"
49 #endif
50 
51 /* Definitions from:
52  *
53  * SCTP reference Implementation Copyright (C) 1999 Cisco And Motorola
54  *
55  * Redistribution and use in source and binary forms, with or without
56  * modification, are permitted provided that the following conditions
57  * are met:
58  *
59  * 1. Redistributions of source code must retain the above copyright
60  *    notice, this list of conditions and the following disclaimer.
61  *
62  * 2. Redistributions in binary form must reproduce the above copyright
63  *    notice, this list of conditions and the following disclaimer in the
64  *    documentation and/or other materials provided with the distribution.
65  *
66  * 3. Neither the name of Cisco nor of Motorola may be used
67  *    to endorse or promote products derived from this software without
68  *    specific prior written permission.
69  *
70  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
71  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
72  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
73  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
74  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
75  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
76  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
77  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
78  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
79  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
80  * SUCH DAMAGE.
81  *
82  * This file is part of the SCTP reference Implementation
83  *
84  *
85  * Please send any bug reports or fixes you make to one of the following email
86  * addresses:
87  *
88  * rstewar1@email.mot.com
89  * kmorneau@cisco.com
90  * qxie1@email.mot.com
91  *
92  * Any bugs reported given to us we will try to fix... any fixes shared will
93  * be incorperated into the next SCTP release.
94  */
95 
96 /* The valid defines for all message
97  * types know to SCTP. 0 is reserved
98  */
99 #define SCTP_DATA		0x00
100 #define SCTP_INITIATION		0x01
101 #define SCTP_INITIATION_ACK	0x02
102 #define SCTP_SELECTIVE_ACK	0x03
103 #define SCTP_HEARTBEAT_REQUEST	0x04
104 #define SCTP_HEARTBEAT_ACK	0x05
105 #define SCTP_ABORT_ASSOCIATION	0x06
106 #define SCTP_SHUTDOWN		0x07
107 #define SCTP_SHUTDOWN_ACK	0x08
108 #define SCTP_OPERATION_ERR	0x09
109 #define SCTP_COOKIE_ECHO	0x0a
110 #define SCTP_COOKIE_ACK         0x0b
111 #define SCTP_ECN_ECHO		0x0c
112 #define SCTP_ECN_CWR		0x0d
113 #define SCTP_SHUTDOWN_COMPLETE	0x0e
114 #define SCTP_FORWARD_CUM_TSN    0xc0
115 #define SCTP_RELIABLE_CNTL      0xc1
116 #define SCTP_RELIABLE_CNTL_ACK  0xc2
117 
118 static const struct tok sctp_chunkid_str[] = {
119 	{ SCTP_DATA,              "DATA"              },
120 	{ SCTP_INITIATION,        "INIT"              },
121 	{ SCTP_INITIATION_ACK,    "INIT ACK"          },
122 	{ SCTP_SELECTIVE_ACK,     "SACK"              },
123 	{ SCTP_HEARTBEAT_REQUEST, "HB REQ"            },
124 	{ SCTP_HEARTBEAT_ACK,     "HB ACK"            },
125 	{ SCTP_ABORT_ASSOCIATION, "ABORT"             },
126 	{ SCTP_SHUTDOWN,          "SHUTDOWN"          },
127 	{ SCTP_SHUTDOWN_ACK,      "SHUTDOWN ACK"      },
128 	{ SCTP_OPERATION_ERR,     "OP ERR"            },
129 	{ SCTP_COOKIE_ECHO,       "COOKIE ECHO"       },
130 	{ SCTP_COOKIE_ACK,        "COOKIE ACK"        },
131 	{ SCTP_ECN_ECHO,          "ECN ECHO"          },
132 	{ SCTP_ECN_CWR,           "ECN CWR"           },
133 	{ SCTP_SHUTDOWN_COMPLETE, "SHUTDOWN COMPLETE" },
134 	{ SCTP_FORWARD_CUM_TSN,   "FOR CUM TSN"       },
135 	{ SCTP_RELIABLE_CNTL,     "REL CTRL"          },
136 	{ SCTP_RELIABLE_CNTL_ACK, "REL CTRL ACK"      },
137 	{ 0, NULL }
138 };
139 
140 /* Data Chuck Specific Flags */
141 #define SCTP_DATA_FRAG_MASK	0x03
142 #define SCTP_DATA_MIDDLE_FRAG	0x00
143 #define SCTP_DATA_LAST_FRAG	0x01
144 #define SCTP_DATA_FIRST_FRAG	0x02
145 #define SCTP_DATA_NOT_FRAG	0x03
146 #define SCTP_DATA_UNORDERED	0x04
147 
148 #define SCTP_ADDRMAX 60
149 
150 #define CHAN_HP 6704
151 #define CHAN_MP 6705
152 #define CHAN_LP 6706
153 
154 /* the sctp common header */
155 
156 struct sctpHeader{
157   uint16_t source;
158   uint16_t destination;
159   uint32_t verificationTag;
160   uint32_t adler32;
161 };
162 
163 /* various descriptor parsers */
164 
165 struct sctpChunkDesc{
166   uint8_t chunkID;
167   uint8_t chunkFlg;
168   uint16_t chunkLength;
169 };
170 
171 struct sctpParamDesc{
172   uint16_t paramType;
173   uint16_t paramLength;
174 };
175 
176 
177 struct sctpRelChunkDesc{
178   struct sctpChunkDesc chk;
179   uint32_t serialNumber;
180 };
181 
182 struct sctpVendorSpecificParam {
183   struct sctpParamDesc p;  /* type must be 0xfffe */
184   uint32_t vendorId;	   /* vendor ID from RFC 1700 */
185   uint16_t vendorSpecificType;
186   uint16_t vendorSpecificLen;
187 };
188 
189 
190 /* Structures for the control parts */
191 
192 
193 
194 /* Sctp association init request/ack */
195 
196 /* this is used for init ack, too */
197 struct sctpInitiation{
198   uint32_t initTag;		/* tag of mine */
199   uint32_t rcvWindowCredit;	/* rwnd */
200   uint16_t NumPreopenStreams;	/* OS */
201   uint16_t MaxInboundStreams;     /* MIS */
202   uint32_t initialTSN;
203   /* optional param's follow in sctpParamDesc form */
204 };
205 
206 struct sctpV4IpAddress{
207   struct sctpParamDesc p;	/* type is set to SCTP_IPV4_PARAM_TYPE, len=10 */
208   uint32_t  ipAddress;
209 };
210 
211 
212 struct sctpV6IpAddress{
213   struct sctpParamDesc p;	/* type is set to SCTP_IPV6_PARAM_TYPE, len=22 */
214   uint8_t  ipAddress[16];
215 };
216 
217 struct sctpDNSName{
218   struct sctpParamDesc param;
219   uint8_t name[1];
220 };
221 
222 
223 struct sctpCookiePreserve{
224   struct sctpParamDesc p;	/* type is set to SCTP_COOKIE_PRESERVE, len=8 */
225   uint32_t extraTime;
226 };
227 
228 
229 struct sctpTimeStamp{
230   uint32_t ts_sec;
231   uint32_t ts_usec;
232 };
233 
234 /* wire structure of my cookie */
235 struct cookieMessage{
236   uint32_t TieTag_curTag;		/* copied from assoc if present */
237   uint32_t TieTag_hisTag; 		/* copied from assoc if present */
238   int32_t cookieLife;			/* life I will award this cookie */
239   struct sctpTimeStamp timeEnteringState; /* the time I built cookie */
240   struct sctpInitiation initAckISent;	/* the INIT-ACK that I sent to my peer */
241   uint32_t addressWhereISent[4];	/* I make this 4 ints so I get 128bits for future */
242   int32_t addrtype;			/* address type */
243   uint16_t locScope;			/* V6 local scope flag */
244   uint16_t siteScope;			/* V6 site scope flag */
245   /* at the end is tacked on the INIT chunk sent in
246    * its entirety and of course our
247    * signature.
248    */
249 };
250 
251 
252 /* this guy is for use when
253  * I have a initiate message gloming the
254  * things together.
255 
256  */
257 struct sctpUnifiedInit{
258   struct sctpChunkDesc uh;
259   struct sctpInitiation initm;
260 };
261 
262 struct sctpSendableInit{
263   struct sctpHeader mh;
264   struct sctpUnifiedInit msg;
265 };
266 
267 
268 /* Selective Acknowledgement
269  * has the following structure with
270  * a optional ammount of trailing int's
271  * on the last part (based on the numberOfDesc
272  * field).
273  */
274 
275 struct sctpSelectiveAck{
276   uint32_t highestConseqTSN;
277   uint32_t updatedRwnd;
278   uint16_t numberOfdesc;
279   uint16_t numDupTsns;
280 };
281 
282 struct sctpSelectiveFrag{
283   uint16_t fragmentStart;
284   uint16_t fragmentEnd;
285 };
286 
287 
288 struct sctpUnifiedSack{
289   struct sctpChunkDesc uh;
290   struct sctpSelectiveAck sack;
291 };
292 
293 /* for both RTT request/response the
294  * following is sent
295  */
296 
297 struct sctpHBrequest {
298   uint32_t time_value_1;
299   uint32_t time_value_2;
300 };
301 
302 /* here is what I read and respond with to. */
303 struct sctpHBunified{
304   struct sctpChunkDesc hdr;
305   struct sctpParamDesc hb;
306 };
307 
308 
309 /* here is what I send */
310 struct sctpHBsender{
311   struct sctpChunkDesc hdr;
312   struct sctpParamDesc hb;
313   struct sctpHBrequest rtt;
314   int8_t addrFmt[SCTP_ADDRMAX];
315   uint16_t userreq;
316 };
317 
318 
319 
320 /* for the abort and shutdown ACK
321  * we must carry the init tag in the common header. Just the
322  * common header is all that is needed with a chunk descriptor.
323  */
324 struct sctpUnifiedAbort{
325   struct sctpChunkDesc uh;
326 };
327 
328 struct sctpUnifiedAbortLight{
329   struct sctpHeader mh;
330   struct sctpChunkDesc uh;
331 };
332 
333 struct sctpUnifiedAbortHeavy{
334   struct sctpHeader mh;
335   struct sctpChunkDesc uh;
336   uint16_t causeCode;
337   uint16_t causeLen;
338 };
339 
340 /* For the graceful shutdown we must carry
341  * the tag (in common header)  and the highest consequitive acking value
342  */
343 struct sctpShutdown {
344   uint32_t TSN_Seen;
345 };
346 
347 struct sctpUnifiedShutdown{
348   struct sctpChunkDesc uh;
349   struct sctpShutdown shut;
350 };
351 
352 /* in the unified message we add the trailing
353  * stream id since it is the only message
354  * that is defined as a operation error.
355  */
356 struct sctpOpErrorCause{
357   uint16_t cause;
358   uint16_t causeLen;
359 };
360 
361 struct sctpUnifiedOpError{
362   struct sctpChunkDesc uh;
363   struct sctpOpErrorCause c;
364 };
365 
366 struct sctpUnifiedStreamError{
367   struct sctpHeader mh;
368   struct sctpChunkDesc uh;
369   struct sctpOpErrorCause c;
370   uint16_t strmNum;
371   uint16_t reserved;
372 };
373 
374 struct staleCookieMsg{
375   struct sctpHeader mh;
376   struct sctpChunkDesc uh;
377   struct sctpOpErrorCause c;
378   uint32_t moretime;
379 };
380 
381 /* the following is used in all sends
382  * where nothing is needed except the
383  * chunk/type i.e. shutdownAck Abort */
384 
385 struct sctpUnifiedSingleMsg{
386   struct sctpHeader mh;
387   struct sctpChunkDesc uh;
388 };
389 
390 struct sctpDataPart{
391   uint32_t TSN;
392   uint16_t streamId;
393   uint16_t sequence;
394   uint32_t payloadtype;
395 };
396 
397 struct sctpUnifiedDatagram{
398   struct sctpChunkDesc uh;
399   struct sctpDataPart dp;
400 };
401 
402 struct sctpECN_echo{
403   struct sctpChunkDesc uh;
404   uint32_t Lowest_TSN;
405 };
406 
407 
408 struct sctpCWR{
409   struct sctpChunkDesc uh;
410   uint32_t TSN_reduced_at;
411 };
412 
413 static const struct tok ForCES_channels[] = {
414 	{ CHAN_HP, "ForCES HP" },
415 	{ CHAN_MP, "ForCES MP" },
416 	{ CHAN_LP, "ForCES LP" },
417 	{ 0, NULL }
418 };
419 
420 /* data chunk's payload protocol identifiers */
421 
422 #define SCTP_PPID_IUA 1
423 #define SCTP_PPID_M2UA 2
424 #define SCTP_PPID_M3UA 3
425 #define SCTP_PPID_SUA 4
426 #define SCTP_PPID_M2PA 5
427 #define SCTP_PPID_V5UA 6
428 #define SCTP_PPID_H248 7
429 #define SCTP_PPID_BICC 8
430 #define SCTP_PPID_TALI 9
431 #define SCTP_PPID_DUA 10
432 #define SCTP_PPID_ASAP 11
433 #define SCTP_PPID_ENRP 12
434 #define SCTP_PPID_H323 13
435 #define SCTP_PPID_QIPC 14
436 #define SCTP_PPID_SIMCO 15
437 #define SCTP_PPID_DDPSC 16
438 #define SCTP_PPID_DDPSSC 17
439 #define SCTP_PPID_S1AP 18
440 #define SCTP_PPID_RUA 19
441 #define SCTP_PPID_HNBAP 20
442 #define SCTP_PPID_FORCES_HP 21
443 #define SCTP_PPID_FORCES_MP 22
444 #define SCTP_PPID_FORCES_LP 23
445 #define SCTP_PPID_SBC_AP 24
446 #define SCTP_PPID_NBAP 25
447 /* 26 */
448 #define SCTP_PPID_X2AP 27
449 
450 static const struct tok PayloadProto_idents[] = {
451 	{ SCTP_PPID_IUA,    "ISDN Q.921" },
452 	{ SCTP_PPID_M2UA,   "M2UA"   },
453 	{ SCTP_PPID_M3UA,   "M3UA"   },
454 	{ SCTP_PPID_SUA,    "SUA"    },
455 	{ SCTP_PPID_M2PA,   "M2PA"   },
456 	{ SCTP_PPID_V5UA,   "V5.2"   },
457 	{ SCTP_PPID_H248,   "H.248"  },
458 	{ SCTP_PPID_BICC,   "BICC"   },
459 	{ SCTP_PPID_TALI,   "TALI"   },
460 	{ SCTP_PPID_DUA,    "DUA"    },
461 	{ SCTP_PPID_ASAP,   "ASAP"   },
462 	{ SCTP_PPID_ENRP,   "ENRP"   },
463 	{ SCTP_PPID_H323,   "H.323"  },
464 	{ SCTP_PPID_QIPC,   "Q.IPC"  },
465 	{ SCTP_PPID_SIMCO,  "SIMCO"  },
466 	{ SCTP_PPID_DDPSC,  "DDPSC"  },
467 	{ SCTP_PPID_DDPSSC, "DDPSSC" },
468 	{ SCTP_PPID_S1AP,   "S1AP"   },
469 	{ SCTP_PPID_RUA,    "RUA"    },
470 	{ SCTP_PPID_HNBAP,  "HNBAP"  },
471 	{ SCTP_PPID_FORCES_HP, "ForCES HP" },
472 	{ SCTP_PPID_FORCES_MP, "ForCES MP" },
473 	{ SCTP_PPID_FORCES_LP, "ForCES LP" },
474 	{ SCTP_PPID_SBC_AP, "SBc-AP" },
475 	{ SCTP_PPID_NBAP,   "NBAP"   },
476 	/* 26 */
477 	{ SCTP_PPID_X2AP,   "X2AP"   },
478 	{ 0, NULL }
479 };
480 
481 
isForCES_port(u_short Port)482 static inline int isForCES_port(u_short Port)
483 {
484 	if (Port == CHAN_HP)
485 		return 1;
486 	if (Port == CHAN_MP)
487 		return 1;
488 	if (Port == CHAN_LP)
489 		return 1;
490 
491 	return 0;
492 }
493 
sctp_print(netdissect_options * ndo,const u_char * bp,const u_char * bp2,u_int sctpPacketLength)494 void sctp_print(netdissect_options *ndo,
495                 const u_char *bp,        /* beginning of sctp packet */
496                 const u_char *bp2,       /* beginning of enclosing */
497                 u_int sctpPacketLength)  /* ip packet */
498 {
499   const struct sctpHeader *sctpPktHdr;
500   const struct ip *ip;
501 #ifdef INET6
502   const struct ip6_hdr *ip6;
503 #endif
504   const void *endPacketPtr;
505   u_short sourcePort, destPort;
506   int chunkCount;
507   const struct sctpChunkDesc *chunkDescPtr;
508   const void *nextChunk;
509   const char *sep;
510   int isforces = 0;
511 
512 
513   sctpPktHdr = (const struct sctpHeader*) bp;
514   endPacketPtr = (const u_char*)sctpPktHdr+sctpPacketLength;
515 
516   if( (u_long) endPacketPtr > (u_long) ndo->ndo_snapend)
517     endPacketPtr = (const void *) ndo->ndo_snapend;
518   ip = (struct ip *)bp2;
519 #ifdef INET6
520   if (IP_V(ip) == 6)
521     ip6 = (const struct ip6_hdr *)bp2;
522   else
523     ip6 = NULL;
524 #endif /*INET6*/
525   ND_TCHECK(*sctpPktHdr);
526 
527   if (sctpPacketLength < sizeof(struct sctpHeader))
528     {
529       ND_PRINT((ndo, "truncated-sctp - %ld bytes missing!",
530 		   (long)sctpPacketLength-sizeof(struct sctpHeader)));
531       return;
532     }
533 
534   /*    sctpPacketLength -= sizeof(struct sctpHeader);  packet length  */
535   /*  			      is now only as long as the payload  */
536 
537   sourcePort = EXTRACT_16BITS(&sctpPktHdr->source);
538   destPort = EXTRACT_16BITS(&sctpPktHdr->destination);
539 
540 #ifdef INET6
541   if (ip6) {
542     ND_PRINT((ndo, "%s.%d > %s.%d: sctp",
543       ip6addr_string(ndo, &ip6->ip6_src),
544       sourcePort,
545       ip6addr_string(ndo, &ip6->ip6_dst),
546       destPort));
547   } else
548 #endif /*INET6*/
549   {
550     ND_PRINT((ndo, "%s.%d > %s.%d: sctp",
551       ipaddr_string(ndo, &ip->ip_src),
552       sourcePort,
553       ipaddr_string(ndo, &ip->ip_dst),
554       destPort));
555   }
556 
557   if (isForCES_port(sourcePort)) {
558          ND_PRINT((ndo, "[%s]", tok2str(ForCES_channels, NULL, sourcePort)));
559          isforces = 1;
560   }
561   if (isForCES_port(destPort)) {
562          ND_PRINT((ndo, "[%s]", tok2str(ForCES_channels, NULL, destPort)));
563          isforces = 1;
564   }
565 
566   if (ndo->ndo_vflag >= 2)
567     sep = "\n\t";
568   else
569     sep = " (";
570   /* cycle through all chunks, printing information on each one */
571   for (chunkCount = 0,
572 	 chunkDescPtr = (const struct sctpChunkDesc *)
573 	    ((const u_char*) sctpPktHdr + sizeof(struct sctpHeader));
574        chunkDescPtr != NULL &&
575 	 ( (const void *)
576 	    ((const u_char *) chunkDescPtr + sizeof(struct sctpChunkDesc))
577 	   <= endPacketPtr);
578 
579        chunkDescPtr = (const struct sctpChunkDesc *) nextChunk, chunkCount++)
580     {
581       uint16_t chunkLength;
582       const u_char *chunkEnd;
583       uint16_t align;
584 
585       ND_TCHECK(*chunkDescPtr);
586       chunkLength = EXTRACT_16BITS(&chunkDescPtr->chunkLength);
587       if (chunkLength < sizeof(*chunkDescPtr)) {
588         ND_PRINT((ndo, "%s%d) [Bad chunk length %u]", sep, chunkCount+1, chunkLength));
589         break;
590       }
591 
592       ND_TCHECK2(*((uint8_t *)chunkDescPtr), chunkLength);
593       chunkEnd = ((const u_char*)chunkDescPtr + chunkLength);
594 
595       align=chunkLength % 4;
596       if (align != 0)
597 	align = 4 - align;
598 
599       nextChunk = (const void *) (chunkEnd + align);
600 
601       ND_PRINT((ndo, "%s%d) ", sep, chunkCount+1));
602       ND_PRINT((ndo, "[%s] ", tok2str(sctp_chunkid_str, "Unknown chunk type: 0x%x",
603                                       chunkDescPtr->chunkID)));
604       switch (chunkDescPtr->chunkID)
605 	{
606 	case SCTP_DATA :
607 	  {
608 	    const struct sctpDataPart *dataHdrPtr;
609 	    uint32_t ppid;
610 	    const u_char *payloadPtr;
611 	    u_int payload_size;
612 
613 	    if ((chunkDescPtr->chunkFlg & SCTP_DATA_UNORDERED)
614 		== SCTP_DATA_UNORDERED)
615 	      ND_PRINT((ndo, "(U)"));
616 
617 	    if ((chunkDescPtr->chunkFlg & SCTP_DATA_FIRST_FRAG)
618 		== SCTP_DATA_FIRST_FRAG)
619 	      ND_PRINT((ndo, "(B)"));
620 
621 	    if ((chunkDescPtr->chunkFlg & SCTP_DATA_LAST_FRAG)
622 		== SCTP_DATA_LAST_FRAG)
623 	      ND_PRINT((ndo, "(E)"));
624 
625 	    if( ((chunkDescPtr->chunkFlg & SCTP_DATA_UNORDERED)
626 		 == SCTP_DATA_UNORDERED)
627 		||
628 		((chunkDescPtr->chunkFlg & SCTP_DATA_FIRST_FRAG)
629 		 == SCTP_DATA_FIRST_FRAG)
630 		||
631 		((chunkDescPtr->chunkFlg & SCTP_DATA_LAST_FRAG)
632 		 == SCTP_DATA_LAST_FRAG) )
633 	      ND_PRINT((ndo, " "));
634 
635 	    dataHdrPtr=(const struct sctpDataPart*)(chunkDescPtr+1);
636 
637 	    ppid = EXTRACT_32BITS(&dataHdrPtr->payloadtype);
638 	    ND_PRINT((ndo, "[TSN: %u] ", EXTRACT_32BITS(&dataHdrPtr->TSN)));
639 	    ND_PRINT((ndo, "[SID: %u] ", EXTRACT_16BITS(&dataHdrPtr->streamId)));
640 	    ND_PRINT((ndo, "[SSEQ %u] ", EXTRACT_16BITS(&dataHdrPtr->sequence)));
641 	    ND_PRINT((ndo, "[PPID %s] ",
642 		    tok2str(PayloadProto_idents, "0x%x", ppid)));
643 
644 	    if (!isforces) {
645 		isforces = (ppid == SCTP_PPID_FORCES_HP) ||
646 		    (ppid == SCTP_PPID_FORCES_MP) ||
647 		    (ppid == SCTP_PPID_FORCES_LP);
648 	    }
649 
650 	    payloadPtr = (const u_char *) (dataHdrPtr + 1);
651 	    if (EXTRACT_16BITS(&chunkDescPtr->chunkLength) <
652 		    sizeof(struct sctpDataPart) + sizeof(struct sctpChunkDesc) + 1) {
653 		ND_PRINT((ndo, "bogus chunk length %u]", EXTRACT_16BITS(&chunkDescPtr->chunkLength)));
654 		return;
655 	    }
656 
657 	    payload_size = EXTRACT_16BITS(&chunkDescPtr->chunkLength) -
658 		(sizeof(struct sctpDataPart) + sizeof(struct sctpChunkDesc));
659 
660 	    if (isforces) {
661 		forces_print(ndo, payloadPtr, payload_size);
662 	    } else if (ndo->ndo_vflag >= 2) {	/* if verbose output is specified */
663 					/* at the command line */
664 		switch (ppid) {
665 		case SCTP_PPID_M3UA :
666 			m3ua_print(ndo, payloadPtr, payload_size);
667 			break;
668 		default:
669 			ND_PRINT((ndo, "[Payload"));
670 			if (!ndo->ndo_suppress_default_print) {
671 				ND_PRINT((ndo, ":"));
672 				ND_DEFAULTPRINT(payloadPtr, payload_size);
673 			}
674 			ND_PRINT((ndo, "]"));
675 			break;
676 		}
677 	    }
678 	    break;
679 	  }
680 	case SCTP_INITIATION :
681 	  {
682 	    const struct sctpInitiation *init;
683 
684 	    init=(const struct sctpInitiation*)(chunkDescPtr+1);
685 	    ND_PRINT((ndo, "[init tag: %u] ", EXTRACT_32BITS(&init->initTag)));
686 	    ND_PRINT((ndo, "[rwnd: %u] ", EXTRACT_32BITS(&init->rcvWindowCredit)));
687 	    ND_PRINT((ndo, "[OS: %u] ", EXTRACT_16BITS(&init->NumPreopenStreams)));
688 	    ND_PRINT((ndo, "[MIS: %u] ", EXTRACT_16BITS(&init->MaxInboundStreams)));
689 	    ND_PRINT((ndo, "[init TSN: %u] ", EXTRACT_32BITS(&init->initialTSN)));
690 
691 #if(0) /* ALC you can add code for optional params here */
692 	    if( (init+1) < chunkEnd )
693 	      ND_PRINT((ndo, " @@@@@ UNFINISHED @@@@@@%s\n",
694 		     "Optional params present, but not printed."));
695 #endif
696 	    break;
697 	  }
698 	case SCTP_INITIATION_ACK :
699 	  {
700 	    const struct sctpInitiation *init;
701 
702 	    init=(const struct sctpInitiation*)(chunkDescPtr+1);
703 	    ND_PRINT((ndo, "[init tag: %u] ", EXTRACT_32BITS(&init->initTag)));
704 	    ND_PRINT((ndo, "[rwnd: %u] ", EXTRACT_32BITS(&init->rcvWindowCredit)));
705 	    ND_PRINT((ndo, "[OS: %u] ", EXTRACT_16BITS(&init->NumPreopenStreams)));
706 	    ND_PRINT((ndo, "[MIS: %u] ", EXTRACT_16BITS(&init->MaxInboundStreams)));
707 	    ND_PRINT((ndo, "[init TSN: %u] ", EXTRACT_32BITS(&init->initialTSN)));
708 
709 #if(0) /* ALC you can add code for optional params here */
710 	    if( (init+1) < chunkEnd )
711 	      ND_PRINT((ndo, " @@@@@ UNFINISHED @@@@@@%s\n",
712 		     "Optional params present, but not printed."));
713 #endif
714 	    break;
715 	  }
716 	case SCTP_SELECTIVE_ACK:
717 	  {
718 	    const struct sctpSelectiveAck *sack;
719 	    const struct sctpSelectiveFrag *frag;
720 	    int fragNo, tsnNo;
721 	    const u_char *dupTSN;
722 
723 	    sack=(const struct sctpSelectiveAck*)(chunkDescPtr+1);
724 	    ND_PRINT((ndo, "[cum ack %u] ", EXTRACT_32BITS(&sack->highestConseqTSN)));
725 	    ND_PRINT((ndo, "[a_rwnd %u] ", EXTRACT_32BITS(&sack->updatedRwnd)));
726 	    ND_PRINT((ndo, "[#gap acks %u] ", EXTRACT_16BITS(&sack->numberOfdesc)));
727 	    ND_PRINT((ndo, "[#dup tsns %u] ", EXTRACT_16BITS(&sack->numDupTsns)));
728 
729 
730 	    /* print gaps */
731 	    for (frag = ( (const struct sctpSelectiveFrag *)
732 			  ((const struct sctpSelectiveAck *) sack+1)),
733 		   fragNo=0;
734 		 (const void *)frag < nextChunk && fragNo < EXTRACT_16BITS(&sack->numberOfdesc);
735 		 frag++, fragNo++)
736 	      ND_PRINT((ndo, "\n\t\t[gap ack block #%d: start = %u, end = %u] ",
737 		     fragNo+1,
738 		     EXTRACT_32BITS(&sack->highestConseqTSN) + EXTRACT_16BITS(&frag->fragmentStart),
739 		     EXTRACT_32BITS(&sack->highestConseqTSN) + EXTRACT_16BITS(&frag->fragmentEnd)));
740 
741 
742 	    /* print duplicate TSNs */
743 	    for (dupTSN = (const u_char *)frag, tsnNo=0;
744 		 (const void *) dupTSN < nextChunk && tsnNo<EXTRACT_16BITS(&sack->numDupTsns);
745 		 dupTSN += 4, tsnNo++)
746 	      ND_PRINT((ndo, "\n\t\t[dup TSN #%u: %u] ", tsnNo+1,
747 	          EXTRACT_32BITS(dupTSN)));
748 
749 	    break;
750 	  }
751 	}
752 
753 	if (ndo->ndo_vflag < 2)
754 	  sep = ", (";
755     }
756     return;
757 
758 trunc:
759     ND_PRINT((ndo, "[|sctp]"));
760 }
761