print-sctp.c - platform/external/tcpdump - Git at Google

 /* Copyright (c) 2001 NETLAB, Temple University
  * Copyright (c) 2001 Protocol Engineering Lab, University of Delaware
  *
  * Jerry Heinz <[email protected]>
  * John Fiore <[email protected]>
  * Armando L. Caro Jr. <[email protected]>
  *
  * 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.
  */

 /* \summary: Stream Control Transmission Protocol (SCTP) printer */

 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif

 #include "netdissect-stdinc.h"

 #include "netdissect.h"
 #include "addrtoname.h"
 #include "extract.h"
 #include "ip.h"
 #include "ip6.h"

 /* 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:
  *
  * [email protected]
  * [email protected]
  * [email protected]
  *
  * 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

 static const struct tok sctp_chunkid_str[] = {
 	{ SCTP_DATA,              "DATA"              },
 	{ SCTP_INITIATION,        "INIT"              },
 	{ SCTP_INITIATION_ACK,    "INIT ACK"          },
 	{ SCTP_SELECTIVE_ACK,     "SACK"              },
 	{ SCTP_HEARTBEAT_REQUEST, "HB REQ"            },
 	{ SCTP_HEARTBEAT_ACK,     "HB ACK"            },
 	{ SCTP_ABORT_ASSOCIATION, "ABORT"             },
 	{ SCTP_SHUTDOWN,          "SHUTDOWN"          },
 	{ SCTP_SHUTDOWN_ACK,      "SHUTDOWN ACK"      },
 	{ SCTP_OPERATION_ERR,     "OP ERR"            },
 	{ SCTP_COOKIE_ECHO,       "COOKIE ECHO"       },
 	{ SCTP_COOKIE_ACK,        "COOKIE ACK"        },
 	{ SCTP_ECN_ECHO,          "ECN ECHO"          },
 	{ SCTP_ECN_CWR,           "ECN CWR"           },
 	{ SCTP_SHUTDOWN_COMPLETE, "SHUTDOWN COMPLETE" },
 	{ SCTP_FORWARD_CUM_TSN,   "FOR CUM TSN"       },
 	{ SCTP_RELIABLE_CNTL,     "REL CTRL"          },
 	{ SCTP_RELIABLE_CNTL_ACK, "REL CTRL ACK"      },
 	{ 0, NULL }
 };

 /* 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{
   nd_uint16_t source;
   nd_uint16_t destination;
   nd_uint32_t verificationTag;
   nd_uint32_t adler32;
 };

 /* various descriptor parsers */

 struct sctpChunkDesc{
   nd_uint8_t  chunkID;
   nd_uint8_t  chunkFlg;
   nd_uint16_t chunkLength;
 };

 struct sctpParamDesc{
   nd_uint16_t paramType;
   nd_uint16_t paramLength;
 };


 struct sctpRelChunkDesc{
   struct sctpChunkDesc chk;
   nd_uint32_t serialNumber;
 };

 struct sctpVendorSpecificParam {
   struct sctpParamDesc p;  /* type must be 0xfffe */
   nd_uint32_t vendorId;	   /* vendor ID from RFC 1700 */
   nd_uint16_t vendorSpecificType;
   nd_uint16_t vendorSpecificLen;
 };


 /* Structures for the control parts */


 /* Sctp association init request/ack */

 /* this is used for init ack, too */
 struct sctpInitiation{
   nd_uint32_t initTag;			/* tag of mine */
   nd_uint32_t rcvWindowCredit;		/* rwnd */
   nd_uint16_t NumPreopenStreams;	/* OS */
   nd_uint16_t MaxInboundStreams;	/* MIS */
   nd_uint32_t initialTSN;
   /* optional param's follow in sctpParamDesc form */
 };

 struct sctpV4IpAddress{
   struct sctpParamDesc p;	/* type is set to SCTP_IPV4_PARAM_TYPE, len=10 */
   nd_ipv4  ipAddress;
 };


 struct sctpV6IpAddress{
   struct sctpParamDesc p;	/* type is set to SCTP_IPV6_PARAM_TYPE, len=22 */
   nd_ipv6  ipAddress;
 };

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


 struct sctpCookiePreserve{
   struct sctpParamDesc p;	/* type is set to SCTP_COOKIE_PRESERVE, len=8 */
   nd_uint32_t extraTime;
 };


 struct sctpTimeStamp{
   nd_uint32_t ts_sec;
   nd_uint32_t ts_usec;
 };


 /* 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{
   nd_uint32_t highestConseqTSN;
   nd_uint32_t updatedRwnd;
   nd_uint16_t numberOfdesc;
   nd_uint16_t numDupTsns;
 };

 struct sctpSelectiveFrag{
   nd_uint16_t fragmentStart;
   nd_uint16_t fragmentEnd;
 };


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

 /* 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;
   nd_uint16_t causeCode;
   nd_uint16_t causeLen;
 };

 /* For the graceful shutdown we must carry
  * the tag (in common header)  and the highest consequitive acking value
  */
 struct sctpShutdown {
   nd_uint32_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{
   nd_uint16_t cause;
   nd_uint16_t causeLen;
 };

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

 struct sctpUnifiedStreamError{
   struct sctpHeader mh;
   struct sctpChunkDesc uh;
   struct sctpOpErrorCause c;
   nd_uint16_t strmNum;
   nd_uint16_t reserved;
 };

 struct staleCookieMsg{
   struct sctpHeader mh;
   struct sctpChunkDesc uh;
   struct sctpOpErrorCause c;
   nd_uint32_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{
   nd_uint32_t TSN;
   nd_uint16_t streamId;
   nd_uint16_t sequence;
   nd_uint32_t payloadtype;
 };

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

 struct sctpECN_echo{
   struct sctpChunkDesc uh;
   nd_uint32_t Lowest_TSN;
 };


 struct sctpCWR{
   struct sctpChunkDesc uh;
   nd_uint32_t TSN_reduced_at;
 };

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

 /* data chunk's payload protocol identifiers */

 #define SCTP_PPID_IUA 1
 #define SCTP_PPID_M2UA 2
 #define SCTP_PPID_M3UA 3
 #define SCTP_PPID_SUA 4
 #define SCTP_PPID_M2PA 5
 #define SCTP_PPID_V5UA 6
 #define SCTP_PPID_H248 7
 #define SCTP_PPID_BICC 8
 #define SCTP_PPID_TALI 9
 #define SCTP_PPID_DUA 10
 #define SCTP_PPID_ASAP 11
 #define SCTP_PPID_ENRP 12
 #define SCTP_PPID_H323 13
 #define SCTP_PPID_QIPC 14
 #define SCTP_PPID_SIMCO 15
 #define SCTP_PPID_DDPSC 16
 #define SCTP_PPID_DDPSSC 17
 #define SCTP_PPID_S1AP 18
 #define SCTP_PPID_RUA 19
 #define SCTP_PPID_HNBAP 20
 #define SCTP_PPID_FORCES_HP 21
 #define SCTP_PPID_FORCES_MP 22
 #define SCTP_PPID_FORCES_LP 23
 #define SCTP_PPID_SBC_AP 24
 #define SCTP_PPID_NBAP 25
 /* 26 */
 #define SCTP_PPID_X2AP 27

 static const struct tok PayloadProto_idents[] = {
 	{ SCTP_PPID_IUA,    "ISDN Q.921" },
 	{ SCTP_PPID_M2UA,   "M2UA"   },
 	{ SCTP_PPID_M3UA,   "M3UA"   },
 	{ SCTP_PPID_SUA,    "SUA"    },
 	{ SCTP_PPID_M2PA,   "M2PA"   },
 	{ SCTP_PPID_V5UA,   "V5.2"   },
 	{ SCTP_PPID_H248,   "H.248"  },
 	{ SCTP_PPID_BICC,   "BICC"   },
 	{ SCTP_PPID_TALI,   "TALI"   },
 	{ SCTP_PPID_DUA,    "DUA"    },
 	{ SCTP_PPID_ASAP,   "ASAP"   },
 	{ SCTP_PPID_ENRP,   "ENRP"   },
 	{ SCTP_PPID_H323,   "H.323"  },
 	{ SCTP_PPID_QIPC,   "Q.IPC"  },
 	{ SCTP_PPID_SIMCO,  "SIMCO"  },
 	{ SCTP_PPID_DDPSC,  "DDPSC"  },
 	{ SCTP_PPID_DDPSSC, "DDPSSC" },
 	{ SCTP_PPID_S1AP,   "S1AP"   },
 	{ SCTP_PPID_RUA,    "RUA"    },
 	{ SCTP_PPID_HNBAP,  "HNBAP"  },
 	{ SCTP_PPID_FORCES_HP, "ForCES HP" },
 	{ SCTP_PPID_FORCES_MP, "ForCES MP" },
 	{ SCTP_PPID_FORCES_LP, "ForCES LP" },
 	{ SCTP_PPID_SBC_AP, "SBc-AP" },
 	{ SCTP_PPID_NBAP,   "NBAP"   },
 	/* 26 */
 	{ SCTP_PPID_X2AP,   "X2AP"   },
 	{ 0, NULL }
 };


 static 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 */
 {
   u_int sctpPacketLengthRemaining;
   const struct sctpHeader *sctpPktHdr;
   const struct ip *ip;
   const struct ip6_hdr *ip6;
   uint8_t chunkID;
   u_short sourcePort, destPort;
   u_int chunkCount;
   const struct sctpChunkDesc *chunkDescPtr;
   const char *sep;
   int isforces = 0;

   ndo->ndo_protocol = "sctp";
   if (sctpPacketLength < sizeof(struct sctpHeader))
     {
       ND_PRINT("truncated-sctp - %ld bytes missing!",
 		   (long)(sizeof(struct sctpHeader) - sctpPacketLength));
       return;
     }
   sctpPktHdr = (const struct sctpHeader*) bp;
   ND_TCHECK_SIZE(sctpPktHdr);
   sctpPacketLengthRemaining = sctpPacketLength;

   sourcePort = EXTRACT_BE_U_2(sctpPktHdr->source);
   destPort = EXTRACT_BE_U_2(sctpPktHdr->destination);

   ip = (const struct ip *)bp2;
   if (IP_V(ip) == 6)
     ip6 = (const struct ip6_hdr *)bp2;
   else
     ip6 = NULL;

   if (ip6) {
     ND_PRINT("%s.%u > %s.%u: sctp",
       ip6addr_string(ndo, ip6->ip6_src),
       sourcePort,
       ip6addr_string(ndo, ip6->ip6_dst),
       destPort);
   } else
   {
     ND_PRINT("%s.%u > %s.%u: sctp",
       ipaddr_string(ndo, ip->ip_src),
       sourcePort,
       ipaddr_string(ndo, ip->ip_dst),
       destPort);
   }

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

   bp += sizeof(struct sctpHeader);
   sctpPacketLengthRemaining -= sizeof(struct sctpHeader);

   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 *)bp;
       sctpPacketLengthRemaining != 0;
       chunkCount++)
     {
       uint16_t chunkLength, chunkLengthRemaining;
       uint16_t align;

       chunkDescPtr = (const struct sctpChunkDesc *)bp;
       if (sctpPacketLengthRemaining < sizeof(*chunkDescPtr)) {
         ND_PRINT("%s%u) [chunk descriptor cut off at end of packet]", sep, chunkCount+1);
         break;
       }
       ND_TCHECK_SIZE(chunkDescPtr);
       chunkLength = EXTRACT_BE_U_2(chunkDescPtr->chunkLength);
       if (chunkLength < sizeof(*chunkDescPtr)) {
         ND_PRINT("%s%u) [Bad chunk length %u, < size of chunk descriptor]", sep, chunkCount+1, chunkLength);
         break;
       }
       chunkLengthRemaining = chunkLength;

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

       if (sctpPacketLengthRemaining < align) {
         ND_PRINT("%s%u) [Bad chunk length %u, > remaining data in packet]", sep, chunkCount+1, chunkLength);
         break;
       }

       ND_TCHECK_LEN(bp, chunkLength);

       bp += sizeof(*chunkDescPtr);
       sctpPacketLengthRemaining -= sizeof(*chunkDescPtr);
       chunkLengthRemaining -= sizeof(*chunkDescPtr);

       ND_PRINT("%s%u) ", sep, chunkCount+1);
       chunkID = EXTRACT_U_1(chunkDescPtr->chunkID);
       ND_PRINT("[%s] ", tok2str(sctp_chunkid_str, "Unknown chunk type: 0x%x",
                                       chunkID));
       switch (chunkID)
 	{
 	case SCTP_DATA :
 	  {
 	    const struct sctpDataPart *dataHdrPtr;
 	    uint8_t chunkFlg;
 	    uint32_t ppid;
 	    u_int payload_size;

 	    chunkFlg = EXTRACT_U_1(chunkDescPtr->chunkFlg);
 	    if ((chunkFlg & SCTP_DATA_UNORDERED) == SCTP_DATA_UNORDERED)
 	      ND_PRINT("(U)");

 	    if ((chunkFlg & SCTP_DATA_FIRST_FRAG) == SCTP_DATA_FIRST_FRAG)
 	      ND_PRINT("(B)");

 	    if ((chunkFlg & SCTP_DATA_LAST_FRAG) == SCTP_DATA_LAST_FRAG)
 	      ND_PRINT("(E)");

 	    if( ((chunkFlg & SCTP_DATA_UNORDERED) == SCTP_DATA_UNORDERED) ||
 	        ((chunkFlg & SCTP_DATA_FIRST_FRAG) == SCTP_DATA_FIRST_FRAG) ||
 		((chunkFlg & SCTP_DATA_LAST_FRAG) == SCTP_DATA_LAST_FRAG) )
 	      ND_PRINT(" ");

 	    if (chunkLengthRemaining < sizeof(*dataHdrPtr)) {
 		ND_PRINT("bogus chunk length %u]", chunkLength);
 		return;
 	    }
 	    dataHdrPtr=(const struct sctpDataPart*)bp;

 	    ppid = EXTRACT_BE_U_4(dataHdrPtr->payloadtype);
 	    ND_PRINT("[TSN: %u] ", EXTRACT_BE_U_4(dataHdrPtr->TSN));
 	    ND_PRINT("[SID: %u] ", EXTRACT_BE_U_2(dataHdrPtr->streamId));
 	    ND_PRINT("[SSEQ %u] ", EXTRACT_BE_U_2(dataHdrPtr->sequence));
 	    ND_PRINT("[PPID %s] ",
 		    tok2str(PayloadProto_idents, "0x%x", ppid));

 	    if (!isforces) {
 		isforces = (ppid == SCTP_PPID_FORCES_HP) ||
 		    (ppid == SCTP_PPID_FORCES_MP) ||
 		    (ppid == SCTP_PPID_FORCES_LP);
 	    }

 	    bp += sizeof(*dataHdrPtr);
 	    sctpPacketLengthRemaining -= sizeof(*dataHdrPtr);
 	    chunkLengthRemaining -= sizeof(*dataHdrPtr);
 	    payload_size = chunkLengthRemaining;
 	    if (payload_size == 0) {
 		ND_PRINT("bogus chunk length %u]", chunkLength);
 		return;
 	    }

 	    if (isforces) {
 		forces_print(ndo, bp, payload_size);
 	    } else if (ndo->ndo_vflag >= 2) {	/* if verbose output is specified */
 					/* at the command line */
 		switch (ppid) {
 		case SCTP_PPID_M3UA :
 			m3ua_print(ndo, bp, payload_size);
 			break;
 		default:
 			ND_PRINT("[Payload");
 			if (!ndo->ndo_suppress_default_print) {
 				ND_PRINT(":");
 				ND_DEFAULTPRINT(bp, payload_size);
 			}
 			ND_PRINT("]");
 			break;
 		}
 	    }
 	    bp += payload_size;
 	    sctpPacketLengthRemaining -= payload_size;
 	    chunkLengthRemaining -= payload_size;
 	    break;
 	  }
 	case SCTP_INITIATION :
 	  {
 	    const struct sctpInitiation *init;

 	    if (chunkLengthRemaining < sizeof(*init)) {
 		ND_PRINT("bogus chunk length %u]", chunkLength);
 		return;
 	    }
 	    init=(const struct sctpInitiation*)bp;
 	    ND_PRINT("[init tag: %u] ", EXTRACT_BE_U_4(init->initTag));
 	    ND_PRINT("[rwnd: %u] ", EXTRACT_BE_U_4(init->rcvWindowCredit));
 	    ND_PRINT("[OS: %u] ", EXTRACT_BE_U_2(init->NumPreopenStreams));
 	    ND_PRINT("[MIS: %u] ", EXTRACT_BE_U_2(init->MaxInboundStreams));
 	    ND_PRINT("[init TSN: %u] ", EXTRACT_BE_U_4(init->initialTSN));
 	    bp += sizeof(*init);
  	    sctpPacketLengthRemaining -= sizeof(*init);
 	    chunkLengthRemaining -= sizeof(*init);

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

 	    if (chunkLengthRemaining < sizeof(*init)) {
 		ND_PRINT("bogus chunk length %u]", chunkLength);
 		return;
 	    }
 	    init=(const struct sctpInitiation*)bp;
 	    ND_PRINT("[init tag: %u] ", EXTRACT_BE_U_4(init->initTag));
 	    ND_PRINT("[rwnd: %u] ", EXTRACT_BE_U_4(init->rcvWindowCredit));
 	    ND_PRINT("[OS: %u] ", EXTRACT_BE_U_2(init->NumPreopenStreams));
 	    ND_PRINT("[MIS: %u] ", EXTRACT_BE_U_2(init->MaxInboundStreams));
 	    ND_PRINT("[init TSN: %u] ", EXTRACT_BE_U_4(init->initialTSN));
             bp += sizeof(*init);
             sctpPacketLengthRemaining -= sizeof(*init);
             chunkLengthRemaining -= sizeof(*init);

 #if 0 /* ALC you can add code for optional params here */
 	    if( chunkLengthRemaining != 0 )
 	      ND_PRINT(" @@@@@ UNFINISHED @@@@@@%s\n",
 		     "Optional params present, but not printed.");
 #endif
             bp += chunkLengthRemaining;
 	    sctpPacketLengthRemaining -= chunkLengthRemaining;
             chunkLengthRemaining = 0;
 	    break;
 	  }
 	case SCTP_SELECTIVE_ACK:
 	  {
 	    const struct sctpSelectiveAck *sack;
 	    const struct sctpSelectiveFrag *frag;
 	    u_int fragNo, tsnNo;
 	    const u_char *dupTSN;

 	    if (chunkLengthRemaining < sizeof(*sack)) {
 	      ND_PRINT("bogus chunk length %u]", chunkLength);
 	      return;
 	    }
 	    sack=(const struct sctpSelectiveAck*)bp;
 	    ND_PRINT("[cum ack %u] ", EXTRACT_BE_U_4(sack->highestConseqTSN));
 	    ND_PRINT("[a_rwnd %u] ", EXTRACT_BE_U_4(sack->updatedRwnd));
 	    ND_PRINT("[#gap acks %u] ", EXTRACT_BE_U_2(sack->numberOfdesc));
 	    ND_PRINT("[#dup tsns %u] ", EXTRACT_BE_U_2(sack->numDupTsns));
             bp += sizeof(*sack);
 	    sctpPacketLengthRemaining -= sizeof(*sack);
             chunkLengthRemaining -= sizeof(*sack);


 	    /* print gaps */
 	    for (fragNo=0;
 		 chunkLengthRemaining != 0 && fragNo < EXTRACT_BE_U_2(sack->numberOfdesc);
 		 bp += sizeof(*frag), sctpPacketLengthRemaining -= sizeof(*frag), chunkLengthRemaining -= sizeof(*frag), fragNo++) {
 	      if (chunkLengthRemaining < sizeof(*frag)) {
 		ND_PRINT("bogus chunk length %u]", chunkLength);
 		return;
 	      }
 	      frag = (const struct sctpSelectiveFrag *)bp;
 	      ND_PRINT("\n\t\t[gap ack block #%u: start = %u, end = %u] ",
 		     fragNo+1,
 		     EXTRACT_BE_U_4(sack->highestConseqTSN) + EXTRACT_BE_U_2(frag->fragmentStart),
 		     EXTRACT_BE_U_4(sack->highestConseqTSN) + EXTRACT_BE_U_2(frag->fragmentEnd));
 	    }

 	    /* print duplicate TSNs */
 	    for (tsnNo=0;
 		 chunkLengthRemaining != 0 && tsnNo<EXTRACT_BE_U_2(sack->numDupTsns);
 		 bp += 4, sctpPacketLengthRemaining -= 4, chunkLengthRemaining -= 4, tsnNo++) {
 	      if (chunkLengthRemaining < 4) {
 		ND_PRINT("bogus chunk length %u]", chunkLength);
 		return;
 	      }
               dupTSN = (const u_char *)bp;
 	      ND_PRINT("\n\t\t[dup TSN #%u: %u] ", tsnNo+1,
 	        EXTRACT_BE_U_4(dupTSN));
 	    }
 	    break;
 	  }
 	default :
 	  {
             bp += chunkLengthRemaining;
             sctpPacketLengthRemaining -= chunkLengthRemaining;
             chunkLengthRemaining = 0;
 	    break;
 	  }
 	}

       /*
        * Any extra stuff at the end of the chunk?
        * XXX - report this?
        */
       bp += chunkLengthRemaining;
       sctpPacketLengthRemaining -= chunkLengthRemaining;

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

       if (align != 0) {
 	/*
 	 * Fail if the alignment padding isn't in the captured data.
 	 * Otherwise, skip it.
 	 */
 	ND_TCHECK_LEN(bp, align);
 	bp += align;
 	sctpPacketLengthRemaining -= align;
       }
     }
     return;

 trunc:
     nd_print_trunc(ndo);
 }
	/* Copyright (c) 2001 NETLAB, Temple University
	* Copyright (c) 2001 Protocol Engineering Lab, University of Delaware
	*
	* Jerry Heinz <[email protected]>
	* John Fiore <[email protected]>
	* Armando L. Caro Jr. <[email protected]>
	*
	* 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.
	*/

	/* \summary: Stream Control Transmission Protocol (SCTP) printer */

	#ifdef HAVE_CONFIG_H
	#include <config.h>
	#endif

	#include "netdissect-stdinc.h"

	#include "netdissect.h"
	#include "addrtoname.h"
	#include "extract.h"
	#include "ip.h"
	#include "ip6.h"

	/* 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:
	*
	* [email protected]
	* [email protected]
	* [email protected]
	*
	* 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

	static const struct tok sctp_chunkid_str[] = {
	{ SCTP_DATA, "DATA" },
	{ SCTP_INITIATION, "INIT" },
	{ SCTP_INITIATION_ACK, "INIT ACK" },
	{ SCTP_SELECTIVE_ACK, "SACK" },
	{ SCTP_HEARTBEAT_REQUEST, "HB REQ" },
	{ SCTP_HEARTBEAT_ACK, "HB ACK" },
	{ SCTP_ABORT_ASSOCIATION, "ABORT" },
	{ SCTP_SHUTDOWN, "SHUTDOWN" },
	{ SCTP_SHUTDOWN_ACK, "SHUTDOWN ACK" },
	{ SCTP_OPERATION_ERR, "OP ERR" },
	{ SCTP_COOKIE_ECHO, "COOKIE ECHO" },
	{ SCTP_COOKIE_ACK, "COOKIE ACK" },
	{ SCTP_ECN_ECHO, "ECN ECHO" },
	{ SCTP_ECN_CWR, "ECN CWR" },
	{ SCTP_SHUTDOWN_COMPLETE, "SHUTDOWN COMPLETE" },
	{ SCTP_FORWARD_CUM_TSN, "FOR CUM TSN" },
	{ SCTP_RELIABLE_CNTL, "REL CTRL" },
	{ SCTP_RELIABLE_CNTL_ACK, "REL CTRL ACK" },
	{ 0, NULL }
	};

	/* 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{
	nd_uint16_t source;
	nd_uint16_t destination;
	nd_uint32_t verificationTag;
	nd_uint32_t adler32;
	};

	/* various descriptor parsers */

	struct sctpChunkDesc{
	nd_uint8_t chunkID;
	nd_uint8_t chunkFlg;
	nd_uint16_t chunkLength;
	};

	struct sctpParamDesc{
	nd_uint16_t paramType;
	nd_uint16_t paramLength;
	};


	struct sctpRelChunkDesc{
	struct sctpChunkDesc chk;
	nd_uint32_t serialNumber;
	};

	struct sctpVendorSpecificParam {
	struct sctpParamDesc p; /* type must be 0xfffe */
	nd_uint32_t vendorId; /* vendor ID from RFC 1700 */
	nd_uint16_t vendorSpecificType;
	nd_uint16_t vendorSpecificLen;
	};


	/* Structures for the control parts */



	/* Sctp association init request/ack */

	/* this is used for init ack, too */
	struct sctpInitiation{
	nd_uint32_t initTag; /* tag of mine */
	nd_uint32_t rcvWindowCredit; /* rwnd */
	nd_uint16_t NumPreopenStreams; /* OS */
	nd_uint16_t MaxInboundStreams; /* MIS */
	nd_uint32_t initialTSN;
	/* optional param's follow in sctpParamDesc form */
	};

	struct sctpV4IpAddress{
	struct sctpParamDesc p; /* type is set to SCTP_IPV4_PARAM_TYPE, len=10 */
	nd_ipv4 ipAddress;
	};


	struct sctpV6IpAddress{
	struct sctpParamDesc p; /* type is set to SCTP_IPV6_PARAM_TYPE, len=22 */
	nd_ipv6 ipAddress;
	};

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


	struct sctpCookiePreserve{
	struct sctpParamDesc p; /* type is set to SCTP_COOKIE_PRESERVE, len=8 */
	nd_uint32_t extraTime;
	};


	struct sctpTimeStamp{
	nd_uint32_t ts_sec;
	nd_uint32_t ts_usec;
	};


	/* 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{
	nd_uint32_t highestConseqTSN;
	nd_uint32_t updatedRwnd;
	nd_uint16_t numberOfdesc;
	nd_uint16_t numDupTsns;
	};

	struct sctpSelectiveFrag{
	nd_uint16_t fragmentStart;
	nd_uint16_t fragmentEnd;
	};


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

	/* 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;
	nd_uint16_t causeCode;
	nd_uint16_t causeLen;
	};

	/* For the graceful shutdown we must carry
	* the tag (in common header) and the highest consequitive acking value
	*/
	struct sctpShutdown {
	nd_uint32_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{
	nd_uint16_t cause;
	nd_uint16_t causeLen;
	};

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

	struct sctpUnifiedStreamError{
	struct sctpHeader mh;
	struct sctpChunkDesc uh;
	struct sctpOpErrorCause c;
	nd_uint16_t strmNum;
	nd_uint16_t reserved;
	};

	struct staleCookieMsg{
	struct sctpHeader mh;
	struct sctpChunkDesc uh;
	struct sctpOpErrorCause c;
	nd_uint32_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{
	nd_uint32_t TSN;
	nd_uint16_t streamId;
	nd_uint16_t sequence;
	nd_uint32_t payloadtype;
	};

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

	struct sctpECN_echo{
	struct sctpChunkDesc uh;
	nd_uint32_t Lowest_TSN;
	};


	struct sctpCWR{
	struct sctpChunkDesc uh;
	nd_uint32_t TSN_reduced_at;
	};

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

	/* data chunk's payload protocol identifiers */

	#define SCTP_PPID_IUA 1
	#define SCTP_PPID_M2UA 2
	#define SCTP_PPID_M3UA 3
	#define SCTP_PPID_SUA 4
	#define SCTP_PPID_M2PA 5
	#define SCTP_PPID_V5UA 6
	#define SCTP_PPID_H248 7
	#define SCTP_PPID_BICC 8
	#define SCTP_PPID_TALI 9
	#define SCTP_PPID_DUA 10
	#define SCTP_PPID_ASAP 11
	#define SCTP_PPID_ENRP 12
	#define SCTP_PPID_H323 13
	#define SCTP_PPID_QIPC 14
	#define SCTP_PPID_SIMCO 15
	#define SCTP_PPID_DDPSC 16
	#define SCTP_PPID_DDPSSC 17
	#define SCTP_PPID_S1AP 18
	#define SCTP_PPID_RUA 19
	#define SCTP_PPID_HNBAP 20
	#define SCTP_PPID_FORCES_HP 21
	#define SCTP_PPID_FORCES_MP 22
	#define SCTP_PPID_FORCES_LP 23
	#define SCTP_PPID_SBC_AP 24
	#define SCTP_PPID_NBAP 25
	/* 26 */
	#define SCTP_PPID_X2AP 27

	static const struct tok PayloadProto_idents[] = {
	{ SCTP_PPID_IUA, "ISDN Q.921" },
	{ SCTP_PPID_M2UA, "M2UA" },
	{ SCTP_PPID_M3UA, "M3UA" },
	{ SCTP_PPID_SUA, "SUA" },
	{ SCTP_PPID_M2PA, "M2PA" },
	{ SCTP_PPID_V5UA, "V5.2" },
	{ SCTP_PPID_H248, "H.248" },
	{ SCTP_PPID_BICC, "BICC" },
	{ SCTP_PPID_TALI, "TALI" },
	{ SCTP_PPID_DUA, "DUA" },
	{ SCTP_PPID_ASAP, "ASAP" },
	{ SCTP_PPID_ENRP, "ENRP" },
	{ SCTP_PPID_H323, "H.323" },
	{ SCTP_PPID_QIPC, "Q.IPC" },
	{ SCTP_PPID_SIMCO, "SIMCO" },
	{ SCTP_PPID_DDPSC, "DDPSC" },
	{ SCTP_PPID_DDPSSC, "DDPSSC" },
	{ SCTP_PPID_S1AP, "S1AP" },
	{ SCTP_PPID_RUA, "RUA" },
	{ SCTP_PPID_HNBAP, "HNBAP" },
	{ SCTP_PPID_FORCES_HP, "ForCES HP" },
	{ SCTP_PPID_FORCES_MP, "ForCES MP" },
	{ SCTP_PPID_FORCES_LP, "ForCES LP" },
	{ SCTP_PPID_SBC_AP, "SBc-AP" },
	{ SCTP_PPID_NBAP, "NBAP" },
	/* 26 */
	{ SCTP_PPID_X2AP, "X2AP" },
	{ 0, NULL }
	};


	static 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 */
	{
	u_int sctpPacketLengthRemaining;
	const struct sctpHeader *sctpPktHdr;
	const struct ip *ip;
	const struct ip6_hdr *ip6;
	uint8_t chunkID;
	u_short sourcePort, destPort;
	u_int chunkCount;
	const struct sctpChunkDesc *chunkDescPtr;
	const char *sep;
	int isforces = 0;

	ndo->ndo_protocol = "sctp";
	if (sctpPacketLength < sizeof(struct sctpHeader))
	{
	ND_PRINT("truncated-sctp - %ld bytes missing!",
	(long)(sizeof(struct sctpHeader) - sctpPacketLength));
	return;
	}
	sctpPktHdr = (const struct sctpHeader*) bp;
	ND_TCHECK_SIZE(sctpPktHdr);
	sctpPacketLengthRemaining = sctpPacketLength;

	sourcePort = EXTRACT_BE_U_2(sctpPktHdr->source);
	destPort = EXTRACT_BE_U_2(sctpPktHdr->destination);

	ip = (const struct ip *)bp2;
	if (IP_V(ip) == 6)
	ip6 = (const struct ip6_hdr *)bp2;
	else
	ip6 = NULL;

	if (ip6) {
	ND_PRINT("%s.%u > %s.%u: sctp",
	ip6addr_string(ndo, ip6->ip6_src),
	sourcePort,
	ip6addr_string(ndo, ip6->ip6_dst),
	destPort);
	} else
	{
	ND_PRINT("%s.%u > %s.%u: sctp",
	ipaddr_string(ndo, ip->ip_src),
	sourcePort,
	ipaddr_string(ndo, ip->ip_dst),
	destPort);
	}

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

	bp += sizeof(struct sctpHeader);
	sctpPacketLengthRemaining -= sizeof(struct sctpHeader);

	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 *)bp;
	sctpPacketLengthRemaining != 0;
	chunkCount++)
	{
	uint16_t chunkLength, chunkLengthRemaining;
	uint16_t align;

	chunkDescPtr = (const struct sctpChunkDesc *)bp;
	if (sctpPacketLengthRemaining < sizeof(*chunkDescPtr)) {
	ND_PRINT("%s%u) [chunk descriptor cut off at end of packet]", sep, chunkCount+1);
	break;
	}
	ND_TCHECK_SIZE(chunkDescPtr);
	chunkLength = EXTRACT_BE_U_2(chunkDescPtr->chunkLength);
	if (chunkLength < sizeof(*chunkDescPtr)) {
	ND_PRINT("%s%u) [Bad chunk length %u, < size of chunk descriptor]", sep, chunkCount+1, chunkLength);
	break;
	}
	chunkLengthRemaining = chunkLength;

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

	if (sctpPacketLengthRemaining < align) {
	ND_PRINT("%s%u) [Bad chunk length %u, > remaining data in packet]", sep, chunkCount+1, chunkLength);
	break;
	}

	ND_TCHECK_LEN(bp, chunkLength);

	bp += sizeof(*chunkDescPtr);
	sctpPacketLengthRemaining -= sizeof(*chunkDescPtr);
	chunkLengthRemaining -= sizeof(*chunkDescPtr);

	ND_PRINT("%s%u) ", sep, chunkCount+1);
	chunkID = EXTRACT_U_1(chunkDescPtr->chunkID);
	ND_PRINT("[%s] ", tok2str(sctp_chunkid_str, "Unknown chunk type: 0x%x",
	chunkID));
	switch (chunkID)
	{
	case SCTP_DATA :
	{
	const struct sctpDataPart *dataHdrPtr;
	uint8_t chunkFlg;
	uint32_t ppid;
	u_int payload_size;

	chunkFlg = EXTRACT_U_1(chunkDescPtr->chunkFlg);
	if ((chunkFlg & SCTP_DATA_UNORDERED) == SCTP_DATA_UNORDERED)
	ND_PRINT("(U)");

	if ((chunkFlg & SCTP_DATA_FIRST_FRAG) == SCTP_DATA_FIRST_FRAG)
	ND_PRINT("(B)");

	if ((chunkFlg & SCTP_DATA_LAST_FRAG) == SCTP_DATA_LAST_FRAG)
	ND_PRINT("(E)");

	if( ((chunkFlg & SCTP_DATA_UNORDERED) == SCTP_DATA_UNORDERED) \|\|
	((chunkFlg & SCTP_DATA_FIRST_FRAG) == SCTP_DATA_FIRST_FRAG) \|\|
	((chunkFlg & SCTP_DATA_LAST_FRAG) == SCTP_DATA_LAST_FRAG) )
	ND_PRINT(" ");

	if (chunkLengthRemaining < sizeof(*dataHdrPtr)) {
	ND_PRINT("bogus chunk length %u]", chunkLength);
	return;
	}
	dataHdrPtr=(const struct sctpDataPart*)bp;

	ppid = EXTRACT_BE_U_4(dataHdrPtr->payloadtype);
	ND_PRINT("[TSN: %u] ", EXTRACT_BE_U_4(dataHdrPtr->TSN));
	ND_PRINT("[SID: %u] ", EXTRACT_BE_U_2(dataHdrPtr->streamId));
	ND_PRINT("[SSEQ %u] ", EXTRACT_BE_U_2(dataHdrPtr->sequence));
	ND_PRINT("[PPID %s] ",
	tok2str(PayloadProto_idents, "0x%x", ppid));

	if (!isforces) {
	isforces = (ppid == SCTP_PPID_FORCES_HP) \|\|
	(ppid == SCTP_PPID_FORCES_MP) \|\|
	(ppid == SCTP_PPID_FORCES_LP);
	}

	bp += sizeof(*dataHdrPtr);
	sctpPacketLengthRemaining -= sizeof(*dataHdrPtr);
	chunkLengthRemaining -= sizeof(*dataHdrPtr);
	payload_size = chunkLengthRemaining;
	if (payload_size == 0) {
	ND_PRINT("bogus chunk length %u]", chunkLength);
	return;
	}

	if (isforces) {
	forces_print(ndo, bp, payload_size);
	} else if (ndo->ndo_vflag >= 2) { /* if verbose output is specified */
	/* at the command line */
	switch (ppid) {
	case SCTP_PPID_M3UA :
	m3ua_print(ndo, bp, payload_size);
	break;
	default:
	ND_PRINT("[Payload");
	if (!ndo->ndo_suppress_default_print) {
	ND_PRINT(":");
	ND_DEFAULTPRINT(bp, payload_size);
	}
	ND_PRINT("]");
	break;
	}
	}
	bp += payload_size;
	sctpPacketLengthRemaining -= payload_size;
	chunkLengthRemaining -= payload_size;
	break;
	}
	case SCTP_INITIATION :
	{
	const struct sctpInitiation *init;

	if (chunkLengthRemaining < sizeof(*init)) {
	ND_PRINT("bogus chunk length %u]", chunkLength);
	return;
	}
	init=(const struct sctpInitiation*)bp;
	ND_PRINT("[init tag: %u] ", EXTRACT_BE_U_4(init->initTag));
	ND_PRINT("[rwnd: %u] ", EXTRACT_BE_U_4(init->rcvWindowCredit));
	ND_PRINT("[OS: %u] ", EXTRACT_BE_U_2(init->NumPreopenStreams));
	ND_PRINT("[MIS: %u] ", EXTRACT_BE_U_2(init->MaxInboundStreams));
	ND_PRINT("[init TSN: %u] ", EXTRACT_BE_U_4(init->initialTSN));
	bp += sizeof(*init);
	sctpPacketLengthRemaining -= sizeof(*init);
	chunkLengthRemaining -= sizeof(*init);

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

	if (chunkLengthRemaining < sizeof(*init)) {
	ND_PRINT("bogus chunk length %u]", chunkLength);
	return;
	}
	init=(const struct sctpInitiation*)bp;
	ND_PRINT("[init tag: %u] ", EXTRACT_BE_U_4(init->initTag));
	ND_PRINT("[rwnd: %u] ", EXTRACT_BE_U_4(init->rcvWindowCredit));
	ND_PRINT("[OS: %u] ", EXTRACT_BE_U_2(init->NumPreopenStreams));
	ND_PRINT("[MIS: %u] ", EXTRACT_BE_U_2(init->MaxInboundStreams));
	ND_PRINT("[init TSN: %u] ", EXTRACT_BE_U_4(init->initialTSN));
	bp += sizeof(*init);
	sctpPacketLengthRemaining -= sizeof(*init);
	chunkLengthRemaining -= sizeof(*init);

	#if 0 /* ALC you can add code for optional params here */
	if( chunkLengthRemaining != 0 )
	ND_PRINT(" @@@@@ UNFINISHED @@@@@@%s\n",
	"Optional params present, but not printed.");
	#endif
	bp += chunkLengthRemaining;
	sctpPacketLengthRemaining -= chunkLengthRemaining;
	chunkLengthRemaining = 0;
	break;
	}
	case SCTP_SELECTIVE_ACK:
	{
	const struct sctpSelectiveAck *sack;
	const struct sctpSelectiveFrag *frag;
	u_int fragNo, tsnNo;
	const u_char *dupTSN;

	if (chunkLengthRemaining < sizeof(*sack)) {
	ND_PRINT("bogus chunk length %u]", chunkLength);
	return;
	}
	sack=(const struct sctpSelectiveAck*)bp;
	ND_PRINT("[cum ack %u] ", EXTRACT_BE_U_4(sack->highestConseqTSN));
	ND_PRINT("[a_rwnd %u] ", EXTRACT_BE_U_4(sack->updatedRwnd));
	ND_PRINT("[#gap acks %u] ", EXTRACT_BE_U_2(sack->numberOfdesc));
	ND_PRINT("[#dup tsns %u] ", EXTRACT_BE_U_2(sack->numDupTsns));
	bp += sizeof(*sack);
	sctpPacketLengthRemaining -= sizeof(*sack);
	chunkLengthRemaining -= sizeof(*sack);


	/* print gaps */
	for (fragNo=0;
	chunkLengthRemaining != 0 && fragNo < EXTRACT_BE_U_2(sack->numberOfdesc);
	bp += sizeof(frag), sctpPacketLengthRemaining -= sizeof(frag), chunkLengthRemaining -= sizeof(*frag), fragNo++) {
	if (chunkLengthRemaining < sizeof(*frag)) {
	ND_PRINT("bogus chunk length %u]", chunkLength);
	return;
	}
	frag = (const struct sctpSelectiveFrag *)bp;
	ND_PRINT("\n\t\t[gap ack block #%u: start = %u, end = %u] ",
	fragNo+1,
	EXTRACT_BE_U_4(sack->highestConseqTSN) + EXTRACT_BE_U_2(frag->fragmentStart),
	EXTRACT_BE_U_4(sack->highestConseqTSN) + EXTRACT_BE_U_2(frag->fragmentEnd));
	}

	/* print duplicate TSNs */
	for (tsnNo=0;
	chunkLengthRemaining != 0 && tsnNo<EXTRACT_BE_U_2(sack->numDupTsns);
	bp += 4, sctpPacketLengthRemaining -= 4, chunkLengthRemaining -= 4, tsnNo++) {
	if (chunkLengthRemaining < 4) {
	ND_PRINT("bogus chunk length %u]", chunkLength);
	return;
	}
	dupTSN = (const u_char *)bp;
	ND_PRINT("\n\t\t[dup TSN #%u: %u] ", tsnNo+1,
	EXTRACT_BE_U_4(dupTSN));
	}
	break;
	}
	default :
	{
	bp += chunkLengthRemaining;
	sctpPacketLengthRemaining -= chunkLengthRemaining;
	chunkLengthRemaining = 0;
	break;
	}
	}

	/*
	* Any extra stuff at the end of the chunk?
	* XXX - report this?
	*/
	bp += chunkLengthRemaining;
	sctpPacketLengthRemaining -= chunkLengthRemaining;

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

	if (align != 0) {
	/*
	* Fail if the alignment padding isn't in the captured data.
	* Otherwise, skip it.
	*/
	ND_TCHECK_LEN(bp, align);
	bp += align;
	sctpPacketLengthRemaining -= align;
	}
	}
	return;

	trunc:
	nd_print_trunc(ndo);
	}