xref: /freebsd/contrib/tcpdump/print-sctp.c (revision ba3c1f5972d7b90feb6e6da47905ff2757e0fe57)
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 /* \summary: Stream Control Transmission Protocol (SCTP) printer */
37 
38 #ifdef HAVE_CONFIG_H
39 #include <config.h>
40 #endif
41 
42 #include "netdissect-stdinc.h"
43 
44 #include "netdissect.h"
45 #include "addrtoname.h"
46 #include "extract.h"
47 #include "ip.h"
48 #include "ip6.h"
49 
50 /* Definitions from:
51  *
52  * SCTP reference Implementation Copyright (C) 1999 Cisco And Motorola
53  *
54  * Redistribution and use in source and binary forms, with or without
55  * modification, are permitted provided that the following conditions
56  * are met:
57  *
58  * 1. Redistributions of source code must retain the above copyright
59  *    notice, this list of conditions and the following disclaimer.
60  *
61  * 2. Redistributions in binary form must reproduce the above copyright
62  *    notice, this list of conditions and the following disclaimer in the
63  *    documentation and/or other materials provided with the distribution.
64  *
65  * 3. Neither the name of Cisco nor of Motorola may be used
66  *    to endorse or promote products derived from this software without
67  *    specific prior written permission.
68  *
69  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
70  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
71  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
72  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
73  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
74  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
75  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
76  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
77  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
78  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
79  * SUCH DAMAGE.
80  *
81  * This file is part of the SCTP reference Implementation
82  *
83  *
84  * Please send any bug reports or fixes you make to one of the following email
85  * addresses:
86  *
87  * rstewar1@email.mot.com
88  * kmorneau@cisco.com
89  * qxie1@email.mot.com
90  *
91  * Any bugs reported given to us we will try to fix... any fixes shared will
92  * be incorporated into the next SCTP release.
93  */
94 
95 /* The valid defines for all message
96  * types know to SCTP. 0 is reserved
97  */
98 #define SCTP_DATA		0x00
99 #define SCTP_INITIATION		0x01
100 #define SCTP_INITIATION_ACK	0x02
101 #define SCTP_SELECTIVE_ACK	0x03
102 #define SCTP_HEARTBEAT_REQUEST	0x04
103 #define SCTP_HEARTBEAT_ACK	0x05
104 #define SCTP_ABORT_ASSOCIATION	0x06
105 #define SCTP_SHUTDOWN		0x07
106 #define SCTP_SHUTDOWN_ACK	0x08
107 #define SCTP_OPERATION_ERR	0x09
108 #define SCTP_COOKIE_ECHO	0x0a
109 #define SCTP_COOKIE_ACK         0x0b
110 #define SCTP_ECN_ECHO		0x0c
111 #define SCTP_ECN_CWR		0x0d
112 #define SCTP_SHUTDOWN_COMPLETE	0x0e
113 #define SCTP_FORWARD_CUM_TSN    0xc0
114 #define SCTP_RELIABLE_CNTL      0xc1
115 #define SCTP_RELIABLE_CNTL_ACK  0xc2
116 
117 static const struct tok sctp_chunkid_str[] = {
118 	{ SCTP_DATA,              "DATA"              },
119 	{ SCTP_INITIATION,        "INIT"              },
120 	{ SCTP_INITIATION_ACK,    "INIT ACK"          },
121 	{ SCTP_SELECTIVE_ACK,     "SACK"              },
122 	{ SCTP_HEARTBEAT_REQUEST, "HB REQ"            },
123 	{ SCTP_HEARTBEAT_ACK,     "HB ACK"            },
124 	{ SCTP_ABORT_ASSOCIATION, "ABORT"             },
125 	{ SCTP_SHUTDOWN,          "SHUTDOWN"          },
126 	{ SCTP_SHUTDOWN_ACK,      "SHUTDOWN ACK"      },
127 	{ SCTP_OPERATION_ERR,     "OP ERR"            },
128 	{ SCTP_COOKIE_ECHO,       "COOKIE ECHO"       },
129 	{ SCTP_COOKIE_ACK,        "COOKIE ACK"        },
130 	{ SCTP_ECN_ECHO,          "ECN ECHO"          },
131 	{ SCTP_ECN_CWR,           "ECN CWR"           },
132 	{ SCTP_SHUTDOWN_COMPLETE, "SHUTDOWN COMPLETE" },
133 	{ SCTP_FORWARD_CUM_TSN,   "FOR CUM TSN"       },
134 	{ SCTP_RELIABLE_CNTL,     "REL CTRL"          },
135 	{ SCTP_RELIABLE_CNTL_ACK, "REL CTRL ACK"      },
136 	{ 0, NULL }
137 };
138 
139 /* Data Chuck Specific Flags */
140 #define SCTP_DATA_FRAG_MASK	0x03
141 #define SCTP_DATA_MIDDLE_FRAG	0x00
142 #define SCTP_DATA_LAST_FRAG	0x01
143 #define SCTP_DATA_FIRST_FRAG	0x02
144 #define SCTP_DATA_NOT_FRAG	0x03
145 #define SCTP_DATA_UNORDERED	0x04
146 
147 #define SCTP_ADDRMAX 60
148 
149 #define CHAN_HP 6704
150 #define CHAN_MP 6705
151 #define CHAN_LP 6706
152 
153 /* the sctp common header */
154 
155 struct sctpHeader{
156   nd_uint16_t source;
157   nd_uint16_t destination;
158   nd_uint32_t verificationTag;
159   nd_uint32_t adler32;
160 };
161 
162 /* various descriptor parsers */
163 
164 struct sctpChunkDesc{
165   nd_uint8_t  chunkID;
166   nd_uint8_t  chunkFlg;
167   nd_uint16_t chunkLength;
168 };
169 
170 struct sctpParamDesc{
171   nd_uint16_t paramType;
172   nd_uint16_t paramLength;
173 };
174 
175 
176 struct sctpRelChunkDesc{
177   struct sctpChunkDesc chk;
178   nd_uint32_t serialNumber;
179 };
180 
181 struct sctpVendorSpecificParam {
182   struct sctpParamDesc p;  /* type must be 0xfffe */
183   nd_uint32_t vendorId;	   /* vendor ID from RFC 1700 */
184   nd_uint16_t vendorSpecificType;
185   nd_uint16_t vendorSpecificLen;
186 };
187 
188 
189 /* Structures for the control parts */
190 
191 
192 
193 /* Sctp association init request/ack */
194 
195 /* this is used for init ack, too */
196 struct sctpInitiation{
197   nd_uint32_t initTag;			/* tag of mine */
198   nd_uint32_t rcvWindowCredit;		/* rwnd */
199   nd_uint16_t NumPreopenStreams;	/* OS */
200   nd_uint16_t MaxInboundStreams;	/* MIS */
201   nd_uint32_t initialTSN;
202   /* optional param's follow in sctpParamDesc form */
203 };
204 
205 struct sctpV4IpAddress{
206   struct sctpParamDesc p;	/* type is set to SCTP_IPV4_PARAM_TYPE, len=10 */
207   nd_ipv4  ipAddress;
208 };
209 
210 
211 struct sctpV6IpAddress{
212   struct sctpParamDesc p;	/* type is set to SCTP_IPV6_PARAM_TYPE, len=22 */
213   nd_ipv6  ipAddress;
214 };
215 
216 struct sctpDNSName{
217   struct sctpParamDesc param;
218   nd_byte name[1];
219 };
220 
221 
222 struct sctpCookiePreserve{
223   struct sctpParamDesc p;	/* type is set to SCTP_COOKIE_PRESERVE, len=8 */
224   nd_uint32_t extraTime;
225 };
226 
227 
228 struct sctpTimeStamp{
229   nd_uint32_t ts_sec;
230   nd_uint32_t ts_usec;
231 };
232 
233 
234 /* this guy is for use when
235  * I have a initiate message gloming the
236  * things together.
237 
238  */
239 struct sctpUnifiedInit{
240   struct sctpChunkDesc uh;
241   struct sctpInitiation initm;
242 };
243 
244 struct sctpSendableInit{
245   struct sctpHeader mh;
246   struct sctpUnifiedInit msg;
247 };
248 
249 
250 /* Selective Acknowledgement
251  * has the following structure with
252  * a optional amount of trailing int's
253  * on the last part (based on the numberOfDesc
254  * field).
255  */
256 
257 struct sctpSelectiveAck{
258   nd_uint32_t highestConseqTSN;
259   nd_uint32_t updatedRwnd;
260   nd_uint16_t numberOfdesc;
261   nd_uint16_t numDupTsns;
262 };
263 
264 struct sctpSelectiveFrag{
265   nd_uint16_t fragmentStart;
266   nd_uint16_t fragmentEnd;
267 };
268 
269 
270 struct sctpUnifiedSack{
271   struct sctpChunkDesc uh;
272   struct sctpSelectiveAck sack;
273 };
274 
275 /* for the abort and shutdown ACK
276  * we must carry the init tag in the common header. Just the
277  * common header is all that is needed with a chunk descriptor.
278  */
279 struct sctpUnifiedAbort{
280   struct sctpChunkDesc uh;
281 };
282 
283 struct sctpUnifiedAbortLight{
284   struct sctpHeader mh;
285   struct sctpChunkDesc uh;
286 };
287 
288 struct sctpUnifiedAbortHeavy{
289   struct sctpHeader mh;
290   struct sctpChunkDesc uh;
291   nd_uint16_t causeCode;
292   nd_uint16_t causeLen;
293 };
294 
295 /* For the graceful shutdown we must carry
296  * the tag (in common header)  and the highest consequitive acking value
297  */
298 struct sctpShutdown {
299   nd_uint32_t TSN_Seen;
300 };
301 
302 struct sctpUnifiedShutdown{
303   struct sctpChunkDesc uh;
304   struct sctpShutdown shut;
305 };
306 
307 /* in the unified message we add the trailing
308  * stream id since it is the only message
309  * that is defined as a operation error.
310  */
311 struct sctpOpErrorCause{
312   nd_uint16_t cause;
313   nd_uint16_t causeLen;
314 };
315 
316 struct sctpUnifiedOpError{
317   struct sctpChunkDesc uh;
318   struct sctpOpErrorCause c;
319 };
320 
321 struct sctpUnifiedStreamError{
322   struct sctpHeader mh;
323   struct sctpChunkDesc uh;
324   struct sctpOpErrorCause c;
325   nd_uint16_t strmNum;
326   nd_uint16_t reserved;
327 };
328 
329 struct staleCookieMsg{
330   struct sctpHeader mh;
331   struct sctpChunkDesc uh;
332   struct sctpOpErrorCause c;
333   nd_uint32_t moretime;
334 };
335 
336 /* the following is used in all sends
337  * where nothing is needed except the
338  * chunk/type i.e. shutdownAck Abort */
339 
340 struct sctpUnifiedSingleMsg{
341   struct sctpHeader mh;
342   struct sctpChunkDesc uh;
343 };
344 
345 struct sctpDataPart{
346   nd_uint32_t TSN;
347   nd_uint16_t streamId;
348   nd_uint16_t sequence;
349   nd_uint32_t payloadtype;
350 };
351 
352 struct sctpUnifiedDatagram{
353   struct sctpChunkDesc uh;
354   struct sctpDataPart dp;
355 };
356 
357 struct sctpECN_echo{
358   struct sctpChunkDesc uh;
359   nd_uint32_t Lowest_TSN;
360 };
361 
362 
363 struct sctpCWR{
364   struct sctpChunkDesc uh;
365   nd_uint32_t TSN_reduced_at;
366 };
367 
368 static const struct tok ForCES_channels[] = {
369 	{ CHAN_HP, "ForCES HP" },
370 	{ CHAN_MP, "ForCES MP" },
371 	{ CHAN_LP, "ForCES LP" },
372 	{ 0, NULL }
373 };
374 
375 /* data chunk's payload protocol identifiers */
376 
377 #define SCTP_PPID_IUA 1
378 #define SCTP_PPID_M2UA 2
379 #define SCTP_PPID_M3UA 3
380 #define SCTP_PPID_SUA 4
381 #define SCTP_PPID_M2PA 5
382 #define SCTP_PPID_V5UA 6
383 #define SCTP_PPID_H248 7
384 #define SCTP_PPID_BICC 8
385 #define SCTP_PPID_TALI 9
386 #define SCTP_PPID_DUA 10
387 #define SCTP_PPID_ASAP 11
388 #define SCTP_PPID_ENRP 12
389 #define SCTP_PPID_H323 13
390 #define SCTP_PPID_QIPC 14
391 #define SCTP_PPID_SIMCO 15
392 #define SCTP_PPID_DDPSC 16
393 #define SCTP_PPID_DDPSSC 17
394 #define SCTP_PPID_S1AP 18
395 #define SCTP_PPID_RUA 19
396 #define SCTP_PPID_HNBAP 20
397 #define SCTP_PPID_FORCES_HP 21
398 #define SCTP_PPID_FORCES_MP 22
399 #define SCTP_PPID_FORCES_LP 23
400 #define SCTP_PPID_SBC_AP 24
401 #define SCTP_PPID_NBAP 25
402 /* 26 */
403 #define SCTP_PPID_X2AP 27
404 
405 static const struct tok PayloadProto_idents[] = {
406 	{ SCTP_PPID_IUA,    "ISDN Q.921" },
407 	{ SCTP_PPID_M2UA,   "M2UA"   },
408 	{ SCTP_PPID_M3UA,   "M3UA"   },
409 	{ SCTP_PPID_SUA,    "SUA"    },
410 	{ SCTP_PPID_M2PA,   "M2PA"   },
411 	{ SCTP_PPID_V5UA,   "V5.2"   },
412 	{ SCTP_PPID_H248,   "H.248"  },
413 	{ SCTP_PPID_BICC,   "BICC"   },
414 	{ SCTP_PPID_TALI,   "TALI"   },
415 	{ SCTP_PPID_DUA,    "DUA"    },
416 	{ SCTP_PPID_ASAP,   "ASAP"   },
417 	{ SCTP_PPID_ENRP,   "ENRP"   },
418 	{ SCTP_PPID_H323,   "H.323"  },
419 	{ SCTP_PPID_QIPC,   "Q.IPC"  },
420 	{ SCTP_PPID_SIMCO,  "SIMCO"  },
421 	{ SCTP_PPID_DDPSC,  "DDPSC"  },
422 	{ SCTP_PPID_DDPSSC, "DDPSSC" },
423 	{ SCTP_PPID_S1AP,   "S1AP"   },
424 	{ SCTP_PPID_RUA,    "RUA"    },
425 	{ SCTP_PPID_HNBAP,  "HNBAP"  },
426 	{ SCTP_PPID_FORCES_HP, "ForCES HP" },
427 	{ SCTP_PPID_FORCES_MP, "ForCES MP" },
428 	{ SCTP_PPID_FORCES_LP, "ForCES LP" },
429 	{ SCTP_PPID_SBC_AP, "SBc-AP" },
430 	{ SCTP_PPID_NBAP,   "NBAP"   },
431 	/* 26 */
432 	{ SCTP_PPID_X2AP,   "X2AP"   },
433 	{ 0, NULL }
434 };
435 
436 
437 static int
438 isForCES_port(u_short Port)
439 {
440 	if (Port == CHAN_HP)
441 		return 1;
442 	if (Port == CHAN_MP)
443 		return 1;
444 	if (Port == CHAN_LP)
445 		return 1;
446 
447 	return 0;
448 }
449 
450 void
451 sctp_print(netdissect_options *ndo,
452 	   const u_char *bp,        /* beginning of sctp packet */
453 	   const u_char *bp2,       /* beginning of enclosing */
454 	   u_int sctpPacketLength)  /* ip packet */
455 {
456   u_int sctpPacketLengthRemaining;
457   const struct sctpHeader *sctpPktHdr;
458   const struct ip *ip;
459   const struct ip6_hdr *ip6;
460   uint8_t chunkID;
461   u_short sourcePort, destPort;
462   u_int chunkCount;
463   const struct sctpChunkDesc *chunkDescPtr;
464   const char *sep;
465   int isforces = 0;
466 
467   ndo->ndo_protocol = "sctp";
468   if (sctpPacketLength < sizeof(struct sctpHeader))
469     {
470       ND_PRINT("truncated-sctp - %zu bytes missing!",
471                sizeof(struct sctpHeader) - sctpPacketLength);
472       return;
473     }
474   sctpPktHdr = (const struct sctpHeader*) bp;
475   ND_TCHECK_SIZE(sctpPktHdr);
476   sctpPacketLengthRemaining = sctpPacketLength;
477 
478   sourcePort = GET_BE_U_2(sctpPktHdr->source);
479   destPort = GET_BE_U_2(sctpPktHdr->destination);
480 
481   ip = (const struct ip *)bp2;
482   if (IP_V(ip) == 6)
483     ip6 = (const struct ip6_hdr *)bp2;
484   else
485     ip6 = NULL;
486 
487   if (ip6) {
488     ND_PRINT("%s.%u > %s.%u: sctp",
489       GET_IP6ADDR_STRING(ip6->ip6_src),
490       sourcePort,
491       GET_IP6ADDR_STRING(ip6->ip6_dst),
492       destPort);
493   } else {
494     ND_PRINT("%s.%u > %s.%u: sctp",
495       GET_IPADDR_STRING(ip->ip_src),
496       sourcePort,
497       GET_IPADDR_STRING(ip->ip_dst),
498       destPort);
499   }
500 
501   if (isForCES_port(sourcePort)) {
502 	 ND_PRINT("[%s]", tok2str(ForCES_channels, NULL, sourcePort));
503 	 isforces = 1;
504   }
505   if (isForCES_port(destPort)) {
506 	 ND_PRINT("[%s]", tok2str(ForCES_channels, NULL, destPort));
507 	 isforces = 1;
508   }
509 
510   bp += sizeof(struct sctpHeader);
511   sctpPacketLengthRemaining -= sizeof(struct sctpHeader);
512 
513   if (ndo->ndo_vflag >= 2)
514     sep = "\n\t";
515   else
516     sep = " (";
517   /* cycle through all chunks, printing information on each one */
518   for (chunkCount = 0, chunkDescPtr = (const struct sctpChunkDesc *)bp;
519       sctpPacketLengthRemaining != 0;
520       chunkCount++)
521     {
522       uint16_t chunkLength, chunkLengthRemaining;
523       uint16_t align;
524 
525       chunkDescPtr = (const struct sctpChunkDesc *)bp;
526       if (sctpPacketLengthRemaining < sizeof(*chunkDescPtr)) {
527 	ND_PRINT("%s%u) [chunk descriptor cut off at end of packet]", sep, chunkCount+1);
528 	break;
529       }
530       ND_TCHECK_SIZE(chunkDescPtr);
531       chunkLength = GET_BE_U_2(chunkDescPtr->chunkLength);
532       if (chunkLength < sizeof(*chunkDescPtr)) {
533 	ND_PRINT("%s%u) [Bad chunk length %u, < size of chunk descriptor]", sep, chunkCount+1, chunkLength);
534 	break;
535       }
536       chunkLengthRemaining = chunkLength;
537 
538       align = chunkLength % 4;
539       if (align != 0)
540 	align = 4 - align;
541 
542       if (sctpPacketLengthRemaining < align) {
543 	ND_PRINT("%s%u) [Bad chunk length %u, > remaining data in packet]", sep, chunkCount+1, chunkLength);
544 	break;
545       }
546 
547       ND_TCHECK_LEN(bp, chunkLength);
548 
549       bp += sizeof(*chunkDescPtr);
550       sctpPacketLengthRemaining -= sizeof(*chunkDescPtr);
551       chunkLengthRemaining -= sizeof(*chunkDescPtr);
552 
553       ND_PRINT("%s%u) ", sep, chunkCount+1);
554       chunkID = GET_U_1(chunkDescPtr->chunkID);
555       ND_PRINT("[%s] ", tok2str(sctp_chunkid_str, "Unknown chunk type: 0x%x",
556 	       chunkID));
557       switch (chunkID)
558 	{
559 	case SCTP_DATA :
560 	  {
561 	    const struct sctpDataPart *dataHdrPtr;
562 	    uint8_t chunkFlg;
563 	    uint32_t ppid;
564 	    uint16_t payload_size;
565 
566 	    chunkFlg = GET_U_1(chunkDescPtr->chunkFlg);
567 	    if ((chunkFlg & SCTP_DATA_UNORDERED) == SCTP_DATA_UNORDERED)
568 	      ND_PRINT("(U)");
569 
570 	    if ((chunkFlg & SCTP_DATA_FIRST_FRAG) == SCTP_DATA_FIRST_FRAG)
571 	      ND_PRINT("(B)");
572 
573 	    if ((chunkFlg & SCTP_DATA_LAST_FRAG) == SCTP_DATA_LAST_FRAG)
574 	      ND_PRINT("(E)");
575 
576 	    if( ((chunkFlg & SCTP_DATA_UNORDERED) == SCTP_DATA_UNORDERED) ||
577 		((chunkFlg & SCTP_DATA_FIRST_FRAG) == SCTP_DATA_FIRST_FRAG) ||
578 		((chunkFlg & SCTP_DATA_LAST_FRAG) == SCTP_DATA_LAST_FRAG) )
579 	      ND_PRINT(" ");
580 
581 	    if (chunkLengthRemaining < sizeof(*dataHdrPtr)) {
582 		ND_PRINT("bogus chunk length %u]", chunkLength);
583 		return;
584 	    }
585 	    dataHdrPtr=(const struct sctpDataPart*)bp;
586 
587 	    ppid = GET_BE_U_4(dataHdrPtr->payloadtype);
588 	    ND_PRINT("[TSN: %u] ", GET_BE_U_4(dataHdrPtr->TSN));
589 	    ND_PRINT("[SID: %u] ", GET_BE_U_2(dataHdrPtr->streamId));
590 	    ND_PRINT("[SSEQ %u] ", GET_BE_U_2(dataHdrPtr->sequence));
591 	    ND_PRINT("[PPID %s] ",
592 		    tok2str(PayloadProto_idents, "0x%x", ppid));
593 
594 	    if (!isforces) {
595 		isforces = (ppid == SCTP_PPID_FORCES_HP) ||
596 		    (ppid == SCTP_PPID_FORCES_MP) ||
597 		    (ppid == SCTP_PPID_FORCES_LP);
598 	    }
599 
600 	    bp += sizeof(*dataHdrPtr);
601 	    sctpPacketLengthRemaining -= sizeof(*dataHdrPtr);
602 	    chunkLengthRemaining -= sizeof(*dataHdrPtr);
603 	    payload_size = chunkLengthRemaining;
604 	    if (payload_size == 0) {
605 		ND_PRINT("bogus chunk length %u]", chunkLength);
606 		return;
607 	    }
608 
609 	    if (isforces) {
610 		forces_print(ndo, bp, payload_size);
611 		/* ndo_protocol reassignment after forces_print() call */
612 		ndo->ndo_protocol = "sctp";
613 	    } else if (ndo->ndo_vflag >= 2) {	/* if verbose output is specified */
614 					/* at the command line */
615 		switch (ppid) {
616 		case SCTP_PPID_M3UA :
617 			m3ua_print(ndo, bp, payload_size);
618 			/* ndo_protocol reassignment after m3ua_print() call */
619 			ndo->ndo_protocol = "sctp";
620 			break;
621 		default:
622 			ND_PRINT("[Payload");
623 			if (!ndo->ndo_suppress_default_print) {
624 				ND_PRINT(":");
625 				ND_DEFAULTPRINT(bp, payload_size);
626 			}
627 			ND_PRINT("]");
628 			break;
629 		}
630 	    }
631 	    bp += payload_size;
632 	    sctpPacketLengthRemaining -= payload_size;
633 	    chunkLengthRemaining -= payload_size;
634 	    break;
635 	  }
636 	case SCTP_INITIATION :
637 	  {
638 	    const struct sctpInitiation *init;
639 
640 	    if (chunkLengthRemaining < sizeof(*init)) {
641 		ND_PRINT("bogus chunk length %u]", chunkLength);
642 		return;
643 	    }
644 	    init=(const struct sctpInitiation*)bp;
645 	    ND_PRINT("[init tag: %u] ", GET_BE_U_4(init->initTag));
646 	    ND_PRINT("[rwnd: %u] ", GET_BE_U_4(init->rcvWindowCredit));
647 	    ND_PRINT("[OS: %u] ", GET_BE_U_2(init->NumPreopenStreams));
648 	    ND_PRINT("[MIS: %u] ", GET_BE_U_2(init->MaxInboundStreams));
649 	    ND_PRINT("[init TSN: %u] ", GET_BE_U_4(init->initialTSN));
650 	    bp += sizeof(*init);
651 	    sctpPacketLengthRemaining -= sizeof(*init);
652 	    chunkLengthRemaining -= sizeof(*init);
653 
654 #if 0 /* ALC you can add code for optional params here */
655 	    if( chunkLengthRemaining != 0 )
656 	      ND_PRINT(" @@@@@ UNFINISHED @@@@@@%s\n",
657 		     "Optional params present, but not printed.");
658 #endif
659 	    bp += chunkLengthRemaining;
660 	    sctpPacketLengthRemaining -= chunkLengthRemaining;
661 	    chunkLengthRemaining = 0;
662 	    break;
663 	  }
664 	case SCTP_INITIATION_ACK :
665 	  {
666 	    const struct sctpInitiation *init;
667 
668 	    if (chunkLengthRemaining < sizeof(*init)) {
669 		ND_PRINT("bogus chunk length %u]", chunkLength);
670 		return;
671 	    }
672 	    init=(const struct sctpInitiation*)bp;
673 	    ND_PRINT("[init tag: %u] ", GET_BE_U_4(init->initTag));
674 	    ND_PRINT("[rwnd: %u] ", GET_BE_U_4(init->rcvWindowCredit));
675 	    ND_PRINT("[OS: %u] ", GET_BE_U_2(init->NumPreopenStreams));
676 	    ND_PRINT("[MIS: %u] ", GET_BE_U_2(init->MaxInboundStreams));
677 	    ND_PRINT("[init TSN: %u] ", GET_BE_U_4(init->initialTSN));
678 	    bp += sizeof(*init);
679 	    sctpPacketLengthRemaining -= sizeof(*init);
680 	    chunkLengthRemaining -= sizeof(*init);
681 
682 #if 0 /* ALC you can add code for optional params here */
683 	    if( chunkLengthRemaining != 0 )
684 	      ND_PRINT(" @@@@@ UNFINISHED @@@@@@%s\n",
685 		     "Optional params present, but not printed.");
686 #endif
687 	    bp += chunkLengthRemaining;
688 	    sctpPacketLengthRemaining -= chunkLengthRemaining;
689 	    chunkLengthRemaining = 0;
690 	    break;
691 	  }
692 	case SCTP_SELECTIVE_ACK:
693 	  {
694 	    const struct sctpSelectiveAck *sack;
695 	    const struct sctpSelectiveFrag *frag;
696 	    u_int fragNo, tsnNo;
697 	    const u_char *dupTSN;
698 
699 	    if (chunkLengthRemaining < sizeof(*sack)) {
700 	      ND_PRINT("bogus chunk length %u]", chunkLength);
701 	      return;
702 	    }
703 	    sack=(const struct sctpSelectiveAck*)bp;
704 	    ND_PRINT("[cum ack %u] ", GET_BE_U_4(sack->highestConseqTSN));
705 	    ND_PRINT("[a_rwnd %u] ", GET_BE_U_4(sack->updatedRwnd));
706 	    ND_PRINT("[#gap acks %u] ", GET_BE_U_2(sack->numberOfdesc));
707 	    ND_PRINT("[#dup tsns %u] ", GET_BE_U_2(sack->numDupTsns));
708 	    bp += sizeof(*sack);
709 	    sctpPacketLengthRemaining -= sizeof(*sack);
710 	    chunkLengthRemaining -= sizeof(*sack);
711 
712 
713 	    /* print gaps */
714 	    for (fragNo=0;
715 		 chunkLengthRemaining != 0 && fragNo < GET_BE_U_2(sack->numberOfdesc);
716 		 bp += sizeof(*frag), sctpPacketLengthRemaining -= sizeof(*frag), chunkLengthRemaining -= sizeof(*frag), fragNo++) {
717 	      if (chunkLengthRemaining < sizeof(*frag)) {
718 		ND_PRINT("bogus chunk length %u]", chunkLength);
719 		return;
720 	      }
721 	      frag = (const struct sctpSelectiveFrag *)bp;
722 	      ND_PRINT("\n\t\t[gap ack block #%u: start = %u, end = %u] ",
723 		     fragNo+1,
724 		     GET_BE_U_4(sack->highestConseqTSN) + GET_BE_U_2(frag->fragmentStart),
725 		     GET_BE_U_4(sack->highestConseqTSN) + GET_BE_U_2(frag->fragmentEnd));
726 	    }
727 
728 	    /* print duplicate TSNs */
729 	    for (tsnNo=0;
730 		 chunkLengthRemaining != 0 && tsnNo<GET_BE_U_2(sack->numDupTsns);
731 		 bp += 4, sctpPacketLengthRemaining -= 4, chunkLengthRemaining -= 4, tsnNo++) {
732 	      if (chunkLengthRemaining < 4) {
733 		ND_PRINT("bogus chunk length %u]", chunkLength);
734 		return;
735 	      }
736 	      dupTSN = (const u_char *)bp;
737 	      ND_PRINT("\n\t\t[dup TSN #%u: %u] ", tsnNo+1,
738 		       GET_BE_U_4(dupTSN));
739 	    }
740 	    break;
741 	  }
742 	default :
743 	  {
744 	    bp += chunkLengthRemaining;
745 	    sctpPacketLengthRemaining -= chunkLengthRemaining;
746 	    chunkLengthRemaining = 0;
747 	    break;
748 	  }
749 	}
750 
751       /*
752        * Any extra stuff at the end of the chunk?
753        * XXX - report this?
754        */
755       bp += chunkLengthRemaining;
756       sctpPacketLengthRemaining -= chunkLengthRemaining;
757 
758       if (ndo->ndo_vflag < 2)
759 	sep = ", (";
760 
761       if (align != 0) {
762 	/*
763 	 * Fail if the alignment padding isn't in the captured data.
764 	 * Otherwise, skip it.
765 	 */
766 	ND_TCHECK_LEN(bp, align);
767 	bp += align;
768 	sctpPacketLengthRemaining -= align;
769       }
770     }
771     return;
772 
773 trunc:
774     nd_print_trunc(ndo);
775 }
776