xref: /freebsd/contrib/tcpdump/print-sctp.c (revision 0a7e5f1f02aad2ff5fff1c60f44c6975fd07e1d9)
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 #include <config.h>
39 
40 #include "netdissect-stdinc.h"
41 
42 #include "netdissect.h"
43 #include "addrtoname.h"
44 #include "extract.h"
45 #include "ip.h"
46 #include "ip6.h"
47 
48 /* Definitions from:
49  *
50  * SCTP reference Implementation Copyright (C) 1999 Cisco And Motorola
51  *
52  * Redistribution and use in source and binary forms, with or without
53  * modification, are permitted provided that the following conditions
54  * are met:
55  *
56  * 1. Redistributions of source code must retain the above copyright
57  *    notice, this list of conditions and the following disclaimer.
58  *
59  * 2. Redistributions in binary form must reproduce the above copyright
60  *    notice, this list of conditions and the following disclaimer in the
61  *    documentation and/or other materials provided with the distribution.
62  *
63  * 3. Neither the name of Cisco nor of Motorola may be used
64  *    to endorse or promote products derived from this software without
65  *    specific prior written permission.
66  *
67  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
68  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
69  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
70  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
71  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
72  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
73  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
74  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
75  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
76  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
77  * SUCH DAMAGE.
78  *
79  * This file is part of the SCTP reference Implementation
80  *
81  *
82  * Please send any bug reports or fixes you make to one of the following email
83  * addresses:
84  *
85  * rstewar1@email.mot.com
86  * kmorneau@cisco.com
87  * qxie1@email.mot.com
88  *
89  * Any bugs reported given to us we will try to fix... any fixes shared will
90  * be incorporated into the next SCTP release.
91  */
92 
93 /* The valid defines for all message
94  * types know to SCTP. 0 is reserved
95  */
96 #define SCTP_DATA		0x00
97 #define SCTP_INITIATION		0x01
98 #define SCTP_INITIATION_ACK	0x02
99 #define SCTP_SELECTIVE_ACK	0x03
100 #define SCTP_HEARTBEAT_REQUEST	0x04
101 #define SCTP_HEARTBEAT_ACK	0x05
102 #define SCTP_ABORT_ASSOCIATION	0x06
103 #define SCTP_SHUTDOWN		0x07
104 #define SCTP_SHUTDOWN_ACK	0x08
105 #define SCTP_OPERATION_ERR	0x09
106 #define SCTP_COOKIE_ECHO	0x0a
107 #define SCTP_COOKIE_ACK         0x0b
108 #define SCTP_ECN_ECHO		0x0c
109 #define SCTP_ECN_CWR		0x0d
110 #define SCTP_SHUTDOWN_COMPLETE	0x0e
111 #define SCTP_FORWARD_CUM_TSN    0xc0
112 #define SCTP_RELIABLE_CNTL      0xc1
113 #define SCTP_RELIABLE_CNTL_ACK  0xc2
114 
115 static const struct tok sctp_chunkid_str[] = {
116 	{ SCTP_DATA,              "DATA"              },
117 	{ SCTP_INITIATION,        "INIT"              },
118 	{ SCTP_INITIATION_ACK,    "INIT ACK"          },
119 	{ SCTP_SELECTIVE_ACK,     "SACK"              },
120 	{ SCTP_HEARTBEAT_REQUEST, "HB REQ"            },
121 	{ SCTP_HEARTBEAT_ACK,     "HB ACK"            },
122 	{ SCTP_ABORT_ASSOCIATION, "ABORT"             },
123 	{ SCTP_SHUTDOWN,          "SHUTDOWN"          },
124 	{ SCTP_SHUTDOWN_ACK,      "SHUTDOWN ACK"      },
125 	{ SCTP_OPERATION_ERR,     "OP ERR"            },
126 	{ SCTP_COOKIE_ECHO,       "COOKIE ECHO"       },
127 	{ SCTP_COOKIE_ACK,        "COOKIE ACK"        },
128 	{ SCTP_ECN_ECHO,          "ECN ECHO"          },
129 	{ SCTP_ECN_CWR,           "ECN CWR"           },
130 	{ SCTP_SHUTDOWN_COMPLETE, "SHUTDOWN COMPLETE" },
131 	{ SCTP_FORWARD_CUM_TSN,   "FOR CUM TSN"       },
132 	{ SCTP_RELIABLE_CNTL,     "REL CTRL"          },
133 	{ SCTP_RELIABLE_CNTL_ACK, "REL CTRL ACK"      },
134 	{ 0, NULL }
135 };
136 
137 /* Data Chuck Specific Flags */
138 #define SCTP_DATA_FRAG_MASK	0x03
139 #define SCTP_DATA_MIDDLE_FRAG	0x00
140 #define SCTP_DATA_LAST_FRAG	0x01
141 #define SCTP_DATA_FIRST_FRAG	0x02
142 #define SCTP_DATA_NOT_FRAG	0x03
143 #define SCTP_DATA_UNORDERED	0x04
144 
145 #define SCTP_ADDRMAX 60
146 
147 #define CHAN_HP 6704
148 #define CHAN_MP 6705
149 #define CHAN_LP 6706
150 
151 /* the sctp common header */
152 
153 struct sctpHeader{
154   nd_uint16_t source;
155   nd_uint16_t destination;
156   nd_uint32_t verificationTag;
157   nd_uint32_t adler32;
158 };
159 
160 /* various descriptor parsers */
161 
162 struct sctpChunkDesc{
163   nd_uint8_t  chunkID;
164   nd_uint8_t  chunkFlg;
165   nd_uint16_t chunkLength;
166 };
167 
168 struct sctpParamDesc{
169   nd_uint16_t paramType;
170   nd_uint16_t paramLength;
171 };
172 
173 
174 struct sctpRelChunkDesc{
175   struct sctpChunkDesc chk;
176   nd_uint32_t serialNumber;
177 };
178 
179 struct sctpVendorSpecificParam {
180   struct sctpParamDesc p;  /* type must be 0xfffe */
181   nd_uint32_t vendorId;	   /* vendor ID from RFC 1700 */
182   nd_uint16_t vendorSpecificType;
183   nd_uint16_t vendorSpecificLen;
184 };
185 
186 
187 /* Structures for the control parts */
188 
189 
190 
191 /* Sctp association init request/ack */
192 
193 /* this is used for init ack, too */
194 struct sctpInitiation{
195   nd_uint32_t initTag;			/* tag of mine */
196   nd_uint32_t rcvWindowCredit;		/* rwnd */
197   nd_uint16_t NumPreopenStreams;	/* OS */
198   nd_uint16_t MaxInboundStreams;	/* MIS */
199   nd_uint32_t initialTSN;
200   /* optional param's follow in sctpParamDesc form */
201 };
202 
203 struct sctpV4IpAddress{
204   struct sctpParamDesc p;	/* type is set to SCTP_IPV4_PARAM_TYPE, len=10 */
205   nd_ipv4  ipAddress;
206 };
207 
208 
209 struct sctpV6IpAddress{
210   struct sctpParamDesc p;	/* type is set to SCTP_IPV6_PARAM_TYPE, len=22 */
211   nd_ipv6  ipAddress;
212 };
213 
214 struct sctpDNSName{
215   struct sctpParamDesc param;
216   nd_byte name[1];
217 };
218 
219 
220 struct sctpCookiePreserve{
221   struct sctpParamDesc p;	/* type is set to SCTP_COOKIE_PRESERVE, len=8 */
222   nd_uint32_t extraTime;
223 };
224 
225 
226 struct sctpTimeStamp{
227   nd_uint32_t ts_sec;
228   nd_uint32_t ts_usec;
229 };
230 
231 
232 /* this guy is for use when
233  * I have a initiate message gloming the
234  * things together.
235 
236  */
237 struct sctpUnifiedInit{
238   struct sctpChunkDesc uh;
239   struct sctpInitiation initm;
240 };
241 
242 struct sctpSendableInit{
243   struct sctpHeader mh;
244   struct sctpUnifiedInit msg;
245 };
246 
247 
248 /* Selective Acknowledgement
249  * has the following structure with
250  * a optional amount of trailing int's
251  * on the last part (based on the numberOfDesc
252  * field).
253  */
254 
255 struct sctpSelectiveAck{
256   nd_uint32_t highestConseqTSN;
257   nd_uint32_t updatedRwnd;
258   nd_uint16_t numberOfdesc;
259   nd_uint16_t numDupTsns;
260 };
261 
262 struct sctpSelectiveFrag{
263   nd_uint16_t fragmentStart;
264   nd_uint16_t fragmentEnd;
265 };
266 
267 
268 struct sctpUnifiedSack{
269   struct sctpChunkDesc uh;
270   struct sctpSelectiveAck sack;
271 };
272 
273 /* for the abort and shutdown ACK
274  * we must carry the init tag in the common header. Just the
275  * common header is all that is needed with a chunk descriptor.
276  */
277 struct sctpUnifiedAbort{
278   struct sctpChunkDesc uh;
279 };
280 
281 struct sctpUnifiedAbortLight{
282   struct sctpHeader mh;
283   struct sctpChunkDesc uh;
284 };
285 
286 struct sctpUnifiedAbortHeavy{
287   struct sctpHeader mh;
288   struct sctpChunkDesc uh;
289   nd_uint16_t causeCode;
290   nd_uint16_t causeLen;
291 };
292 
293 /* For the graceful shutdown we must carry
294  * the tag (in common header)  and the highest consecutive acking value
295  */
296 struct sctpShutdown {
297   nd_uint32_t TSN_Seen;
298 };
299 
300 struct sctpUnifiedShutdown{
301   struct sctpChunkDesc uh;
302   struct sctpShutdown shut;
303 };
304 
305 /* in the unified message we add the trailing
306  * stream id since it is the only message
307  * that is defined as a operation error.
308  */
309 struct sctpOpErrorCause{
310   nd_uint16_t cause;
311   nd_uint16_t causeLen;
312 };
313 
314 struct sctpUnifiedOpError{
315   struct sctpChunkDesc uh;
316   struct sctpOpErrorCause c;
317 };
318 
319 struct sctpUnifiedStreamError{
320   struct sctpHeader mh;
321   struct sctpChunkDesc uh;
322   struct sctpOpErrorCause c;
323   nd_uint16_t strmNum;
324   nd_uint16_t reserved;
325 };
326 
327 struct staleCookieMsg{
328   struct sctpHeader mh;
329   struct sctpChunkDesc uh;
330   struct sctpOpErrorCause c;
331   nd_uint32_t moretime;
332 };
333 
334 /* the following is used in all sends
335  * where nothing is needed except the
336  * chunk/type i.e. shutdownAck Abort */
337 
338 struct sctpUnifiedSingleMsg{
339   struct sctpHeader mh;
340   struct sctpChunkDesc uh;
341 };
342 
343 struct sctpDataPart{
344   nd_uint32_t TSN;
345   nd_uint16_t streamId;
346   nd_uint16_t sequence;
347   nd_uint32_t payloadtype;
348 };
349 
350 struct sctpUnifiedDatagram{
351   struct sctpChunkDesc uh;
352   struct sctpDataPart dp;
353 };
354 
355 struct sctpECN_echo{
356   struct sctpChunkDesc uh;
357   nd_uint32_t Lowest_TSN;
358 };
359 
360 
361 struct sctpCWR{
362   struct sctpChunkDesc uh;
363   nd_uint32_t TSN_reduced_at;
364 };
365 
366 static const struct tok ForCES_channels[] = {
367 	{ CHAN_HP, "ForCES HP" },
368 	{ CHAN_MP, "ForCES MP" },
369 	{ CHAN_LP, "ForCES LP" },
370 	{ 0, NULL }
371 };
372 
373 /* data chunk's payload protocol identifiers */
374 
375 #define SCTP_PPID_IUA 1
376 #define SCTP_PPID_M2UA 2
377 #define SCTP_PPID_M3UA 3
378 #define SCTP_PPID_SUA 4
379 #define SCTP_PPID_M2PA 5
380 #define SCTP_PPID_V5UA 6
381 #define SCTP_PPID_H248 7
382 #define SCTP_PPID_BICC 8
383 #define SCTP_PPID_TALI 9
384 #define SCTP_PPID_DUA 10
385 #define SCTP_PPID_ASAP 11
386 #define SCTP_PPID_ENRP 12
387 #define SCTP_PPID_H323 13
388 #define SCTP_PPID_QIPC 14
389 #define SCTP_PPID_SIMCO 15
390 #define SCTP_PPID_DDPSC 16
391 #define SCTP_PPID_DDPSSC 17
392 #define SCTP_PPID_S1AP 18
393 #define SCTP_PPID_RUA 19
394 #define SCTP_PPID_HNBAP 20
395 #define SCTP_PPID_FORCES_HP 21
396 #define SCTP_PPID_FORCES_MP 22
397 #define SCTP_PPID_FORCES_LP 23
398 #define SCTP_PPID_SBC_AP 24
399 #define SCTP_PPID_NBAP 25
400 /* 26 */
401 #define SCTP_PPID_X2AP 27
402 
403 static const struct tok PayloadProto_idents[] = {
404 	{ SCTP_PPID_IUA,    "ISDN Q.921" },
405 	{ SCTP_PPID_M2UA,   "M2UA"   },
406 	{ SCTP_PPID_M3UA,   "M3UA"   },
407 	{ SCTP_PPID_SUA,    "SUA"    },
408 	{ SCTP_PPID_M2PA,   "M2PA"   },
409 	{ SCTP_PPID_V5UA,   "V5.2"   },
410 	{ SCTP_PPID_H248,   "H.248"  },
411 	{ SCTP_PPID_BICC,   "BICC"   },
412 	{ SCTP_PPID_TALI,   "TALI"   },
413 	{ SCTP_PPID_DUA,    "DUA"    },
414 	{ SCTP_PPID_ASAP,   "ASAP"   },
415 	{ SCTP_PPID_ENRP,   "ENRP"   },
416 	{ SCTP_PPID_H323,   "H.323"  },
417 	{ SCTP_PPID_QIPC,   "Q.IPC"  },
418 	{ SCTP_PPID_SIMCO,  "SIMCO"  },
419 	{ SCTP_PPID_DDPSC,  "DDPSC"  },
420 	{ SCTP_PPID_DDPSSC, "DDPSSC" },
421 	{ SCTP_PPID_S1AP,   "S1AP"   },
422 	{ SCTP_PPID_RUA,    "RUA"    },
423 	{ SCTP_PPID_HNBAP,  "HNBAP"  },
424 	{ SCTP_PPID_FORCES_HP, "ForCES HP" },
425 	{ SCTP_PPID_FORCES_MP, "ForCES MP" },
426 	{ SCTP_PPID_FORCES_LP, "ForCES LP" },
427 	{ SCTP_PPID_SBC_AP, "SBc-AP" },
428 	{ SCTP_PPID_NBAP,   "NBAP"   },
429 	/* 26 */
430 	{ SCTP_PPID_X2AP,   "X2AP"   },
431 	{ 0, NULL }
432 };
433 
434 
435 static int
isForCES_port(u_short Port)436 isForCES_port(u_short Port)
437 {
438 	if (Port == CHAN_HP)
439 		return 1;
440 	if (Port == CHAN_MP)
441 		return 1;
442 	if (Port == CHAN_LP)
443 		return 1;
444 
445 	return 0;
446 }
447 
448 void
sctp_print(netdissect_options * ndo,const u_char * bp,const u_char * bp2,u_int sctpPacketLength)449 sctp_print(netdissect_options *ndo,
450 	   const u_char *bp,        /* beginning of sctp packet */
451 	   const u_char *bp2,       /* beginning of enclosing */
452 	   u_int sctpPacketLength)  /* ip packet */
453 {
454   u_int sctpPacketLengthRemaining;
455   const struct sctpHeader *sctpPktHdr;
456   const struct ip *ip;
457   const struct ip6_hdr *ip6;
458   uint8_t chunkID;
459   u_short sourcePort, destPort;
460   u_int chunkCount;
461   const struct sctpChunkDesc *chunkDescPtr;
462   const char *sep;
463   int isforces = 0;
464 
465   ndo->ndo_protocol = "sctp";
466   if (sctpPacketLength < sizeof(struct sctpHeader))
467     {
468       ND_PRINT("truncated-sctp - %zu bytes missing!",
469                sizeof(struct sctpHeader) - sctpPacketLength);
470       return;
471     }
472   sctpPktHdr = (const struct sctpHeader*) bp;
473   ND_TCHECK_SIZE(sctpPktHdr);
474   sctpPacketLengthRemaining = sctpPacketLength;
475 
476   sourcePort = GET_BE_U_2(sctpPktHdr->source);
477   destPort = GET_BE_U_2(sctpPktHdr->destination);
478 
479   ip = (const struct ip *)bp2;
480   if (IP_V(ip) == 6)
481     ip6 = (const struct ip6_hdr *)bp2;
482   else
483     ip6 = NULL;
484 
485   if (ip6) {
486     ND_PRINT("%s.%u > %s.%u: sctp",
487       GET_IP6ADDR_STRING(ip6->ip6_src),
488       sourcePort,
489       GET_IP6ADDR_STRING(ip6->ip6_dst),
490       destPort);
491   } else {
492     ND_PRINT("%s.%u > %s.%u: sctp",
493       GET_IPADDR_STRING(ip->ip_src),
494       sourcePort,
495       GET_IPADDR_STRING(ip->ip_dst),
496       destPort);
497   }
498 
499   if (isForCES_port(sourcePort)) {
500 	 ND_PRINT("[%s]", tok2str(ForCES_channels, NULL, sourcePort));
501 	 isforces = 1;
502   }
503   if (isForCES_port(destPort)) {
504 	 ND_PRINT("[%s]", tok2str(ForCES_channels, NULL, destPort));
505 	 isforces = 1;
506   }
507 
508   bp += sizeof(struct sctpHeader);
509   sctpPacketLengthRemaining -= sizeof(struct sctpHeader);
510 
511   if (ndo->ndo_vflag >= 2)
512     sep = "\n\t";
513   else
514     sep = " (";
515   /* cycle through all chunks, printing information on each one */
516   for (chunkCount = 0, chunkDescPtr = (const struct sctpChunkDesc *)bp;
517       sctpPacketLengthRemaining != 0;
518       chunkCount++)
519     {
520       uint16_t chunkLength, chunkLengthRemaining;
521       uint16_t align;
522 
523       chunkDescPtr = (const struct sctpChunkDesc *)bp;
524       if (sctpPacketLengthRemaining < sizeof(*chunkDescPtr)) {
525 	ND_PRINT("%s%u) [chunk descriptor cut off at end of packet]", sep, chunkCount+1);
526 	break;
527       }
528       ND_TCHECK_SIZE(chunkDescPtr);
529       chunkLength = GET_BE_U_2(chunkDescPtr->chunkLength);
530       if (chunkLength < sizeof(*chunkDescPtr)) {
531 	ND_PRINT("%s%u) [Bad chunk length %u, < size of chunk descriptor]", sep, chunkCount+1, chunkLength);
532 	break;
533       }
534       chunkLengthRemaining = chunkLength;
535 
536       align = chunkLength % 4;
537       if (align != 0)
538 	align = 4 - align;
539 
540       if (sctpPacketLengthRemaining < align) {
541 	ND_PRINT("%s%u) [Bad chunk length %u, > remaining data in packet]", sep, chunkCount+1, chunkLength);
542 	break;
543       }
544 
545       ND_TCHECK_LEN(bp, chunkLength);
546 
547       bp += sizeof(*chunkDescPtr);
548       sctpPacketLengthRemaining -= sizeof(*chunkDescPtr);
549       chunkLengthRemaining -= sizeof(*chunkDescPtr);
550 
551       ND_PRINT("%s%u) ", sep, chunkCount+1);
552       chunkID = GET_U_1(chunkDescPtr->chunkID);
553       ND_PRINT("[%s] ", tok2str(sctp_chunkid_str, "Unknown chunk type: 0x%x",
554 	       chunkID));
555       switch (chunkID) {
556 	case SCTP_DATA :
557 	  {
558 	    const struct sctpDataPart *dataHdrPtr;
559 	    uint8_t chunkFlg;
560 	    uint32_t ppid;
561 	    uint16_t payload_size;
562 
563 	    chunkFlg = GET_U_1(chunkDescPtr->chunkFlg);
564 	    if ((chunkFlg & SCTP_DATA_UNORDERED) == SCTP_DATA_UNORDERED)
565 	      ND_PRINT("(U)");
566 
567 	    if ((chunkFlg & SCTP_DATA_FIRST_FRAG) == SCTP_DATA_FIRST_FRAG)
568 	      ND_PRINT("(B)");
569 
570 	    if ((chunkFlg & SCTP_DATA_LAST_FRAG) == SCTP_DATA_LAST_FRAG)
571 	      ND_PRINT("(E)");
572 
573 	    if( ((chunkFlg & SCTP_DATA_UNORDERED) == SCTP_DATA_UNORDERED) ||
574 		((chunkFlg & SCTP_DATA_FIRST_FRAG) == SCTP_DATA_FIRST_FRAG) ||
575 		((chunkFlg & SCTP_DATA_LAST_FRAG) == SCTP_DATA_LAST_FRAG) )
576 	      ND_PRINT(" ");
577 
578 	    if (chunkLengthRemaining < sizeof(*dataHdrPtr)) {
579 		ND_PRINT("bogus chunk length %u]", chunkLength);
580 		return;
581 	    }
582 	    dataHdrPtr=(const struct sctpDataPart*)bp;
583 
584 	    ppid = GET_BE_U_4(dataHdrPtr->payloadtype);
585 	    ND_PRINT("[TSN: %u] ", GET_BE_U_4(dataHdrPtr->TSN));
586 	    ND_PRINT("[SID: %u] ", GET_BE_U_2(dataHdrPtr->streamId));
587 	    ND_PRINT("[SSEQ %u] ", GET_BE_U_2(dataHdrPtr->sequence));
588 	    ND_PRINT("[PPID %s] ",
589 		    tok2str(PayloadProto_idents, "0x%x", ppid));
590 
591 	    if (!isforces) {
592 		isforces = (ppid == SCTP_PPID_FORCES_HP) ||
593 		    (ppid == SCTP_PPID_FORCES_MP) ||
594 		    (ppid == SCTP_PPID_FORCES_LP);
595 	    }
596 
597 	    bp += sizeof(*dataHdrPtr);
598 	    sctpPacketLengthRemaining -= sizeof(*dataHdrPtr);
599 	    chunkLengthRemaining -= sizeof(*dataHdrPtr);
600 	    payload_size = chunkLengthRemaining;
601 	    if (payload_size == 0) {
602 		ND_PRINT("bogus chunk length %u]", chunkLength);
603 		return;
604 	    }
605 
606 	    if (isforces) {
607 		forces_print(ndo, bp, payload_size);
608 		/* ndo_protocol reassignment after forces_print() call */
609 		ndo->ndo_protocol = "sctp";
610 	    } else if (ndo->ndo_vflag >= 2) {	/* if verbose output is specified */
611 					/* at the command line */
612 		switch (ppid) {
613 		case SCTP_PPID_M3UA :
614 			m3ua_print(ndo, bp, payload_size);
615 			/* ndo_protocol reassignment after m3ua_print() call */
616 			ndo->ndo_protocol = "sctp";
617 			break;
618 		default:
619 			ND_PRINT("[Payload");
620 			if (!ndo->ndo_suppress_default_print) {
621 				ND_PRINT(":");
622 				ND_DEFAULTPRINT(bp, payload_size);
623 			}
624 			ND_PRINT("]");
625 			break;
626 		}
627 	    }
628 	    bp += payload_size;
629 	    sctpPacketLengthRemaining -= payload_size;
630 	    chunkLengthRemaining -= payload_size;
631 	    break;
632 	  }
633 	case SCTP_INITIATION :
634 	  {
635 	    const struct sctpInitiation *init;
636 
637 	    if (chunkLengthRemaining < sizeof(*init)) {
638 		ND_PRINT("bogus chunk length %u]", chunkLength);
639 		return;
640 	    }
641 	    init=(const struct sctpInitiation*)bp;
642 	    ND_PRINT("[init tag: %u] ", GET_BE_U_4(init->initTag));
643 	    ND_PRINT("[rwnd: %u] ", GET_BE_U_4(init->rcvWindowCredit));
644 	    ND_PRINT("[OS: %u] ", GET_BE_U_2(init->NumPreopenStreams));
645 	    ND_PRINT("[MIS: %u] ", GET_BE_U_2(init->MaxInboundStreams));
646 	    ND_PRINT("[init TSN: %u] ", GET_BE_U_4(init->initialTSN));
647 	    bp += sizeof(*init);
648 	    sctpPacketLengthRemaining -= sizeof(*init);
649 	    chunkLengthRemaining -= sizeof(*init);
650 
651 #if 0 /* ALC you can add code for optional params here */
652 	    if( chunkLengthRemaining != 0 )
653 	      ND_PRINT(" @@@@@ UNFINISHED @@@@@@%s\n",
654 		     "Optional params present, but not printed.");
655 #endif
656 	    bp += chunkLengthRemaining;
657 	    sctpPacketLengthRemaining -= chunkLengthRemaining;
658 	    chunkLengthRemaining = 0;
659 	    break;
660 	  }
661 	case SCTP_INITIATION_ACK :
662 	  {
663 	    const struct sctpInitiation *init;
664 
665 	    if (chunkLengthRemaining < sizeof(*init)) {
666 		ND_PRINT("bogus chunk length %u]", chunkLength);
667 		return;
668 	    }
669 	    init=(const struct sctpInitiation*)bp;
670 	    ND_PRINT("[init tag: %u] ", GET_BE_U_4(init->initTag));
671 	    ND_PRINT("[rwnd: %u] ", GET_BE_U_4(init->rcvWindowCredit));
672 	    ND_PRINT("[OS: %u] ", GET_BE_U_2(init->NumPreopenStreams));
673 	    ND_PRINT("[MIS: %u] ", GET_BE_U_2(init->MaxInboundStreams));
674 	    ND_PRINT("[init TSN: %u] ", GET_BE_U_4(init->initialTSN));
675 	    bp += sizeof(*init);
676 	    sctpPacketLengthRemaining -= sizeof(*init);
677 	    chunkLengthRemaining -= sizeof(*init);
678 
679 #if 0 /* ALC you can add code for optional params here */
680 	    if( chunkLengthRemaining != 0 )
681 	      ND_PRINT(" @@@@@ UNFINISHED @@@@@@%s\n",
682 		     "Optional params present, but not printed.");
683 #endif
684 	    bp += chunkLengthRemaining;
685 	    sctpPacketLengthRemaining -= chunkLengthRemaining;
686 	    chunkLengthRemaining = 0;
687 	    break;
688 	  }
689 	case SCTP_SELECTIVE_ACK:
690 	  {
691 	    const struct sctpSelectiveAck *sack;
692 	    const struct sctpSelectiveFrag *frag;
693 	    u_int fragNo, tsnNo;
694 	    const u_char *dupTSN;
695 
696 	    if (chunkLengthRemaining < sizeof(*sack)) {
697 	      ND_PRINT("bogus chunk length %u]", chunkLength);
698 	      return;
699 	    }
700 	    sack=(const struct sctpSelectiveAck*)bp;
701 	    ND_PRINT("[cum ack %u] ", GET_BE_U_4(sack->highestConseqTSN));
702 	    ND_PRINT("[a_rwnd %u] ", GET_BE_U_4(sack->updatedRwnd));
703 	    ND_PRINT("[#gap acks %u] ", GET_BE_U_2(sack->numberOfdesc));
704 	    ND_PRINT("[#dup tsns %u] ", GET_BE_U_2(sack->numDupTsns));
705 	    bp += sizeof(*sack);
706 	    sctpPacketLengthRemaining -= sizeof(*sack);
707 	    chunkLengthRemaining -= sizeof(*sack);
708 
709 
710 	    /* print gaps */
711 	    for (fragNo=0;
712 		 chunkLengthRemaining != 0 && fragNo < GET_BE_U_2(sack->numberOfdesc);
713 		 bp += sizeof(*frag), sctpPacketLengthRemaining -= sizeof(*frag), chunkLengthRemaining -= sizeof(*frag), fragNo++) {
714 	      if (chunkLengthRemaining < sizeof(*frag)) {
715 		ND_PRINT("bogus chunk length %u]", chunkLength);
716 		return;
717 	      }
718 	      frag = (const struct sctpSelectiveFrag *)bp;
719 	      ND_PRINT("\n\t\t[gap ack block #%u: start = %u, end = %u] ",
720 		     fragNo+1,
721 		     GET_BE_U_4(sack->highestConseqTSN) + GET_BE_U_2(frag->fragmentStart),
722 		     GET_BE_U_4(sack->highestConseqTSN) + GET_BE_U_2(frag->fragmentEnd));
723 	    }
724 
725 	    /* print duplicate TSNs */
726 	    for (tsnNo=0;
727 		 chunkLengthRemaining != 0 && tsnNo<GET_BE_U_2(sack->numDupTsns);
728 		 bp += 4, sctpPacketLengthRemaining -= 4, chunkLengthRemaining -= 4, tsnNo++) {
729 	      if (chunkLengthRemaining < 4) {
730 		ND_PRINT("bogus chunk length %u]", chunkLength);
731 		return;
732 	      }
733 	      dupTSN = (const u_char *)bp;
734 	      ND_PRINT("\n\t\t[dup TSN #%u: %u] ", tsnNo+1,
735 		       GET_BE_U_4(dupTSN));
736 	    }
737 	    break;
738 	  }
739 	default :
740 	  {
741 	    bp += chunkLengthRemaining;
742 	    sctpPacketLengthRemaining -= chunkLengthRemaining;
743 	    chunkLengthRemaining = 0;
744 	    break;
745 	  }
746 	}
747 
748       /*
749        * Any extra stuff at the end of the chunk?
750        * XXX - report this?
751        */
752       bp += chunkLengthRemaining;
753       sctpPacketLengthRemaining -= chunkLengthRemaining;
754 
755       if (ndo->ndo_vflag < 2)
756 	sep = ", (";
757 
758       if (align != 0) {
759 	/*
760 	 * Fail if the alignment padding isn't in the captured data.
761 	 * Otherwise, skip it.
762 	 */
763 	ND_TCHECK_LEN(bp, align);
764 	bp += align;
765 	sctpPacketLengthRemaining -= align;
766       }
767     }
768     return;
769 
770 trunc:
771     nd_print_trunc(ndo);
772 }
773