Add SCTP dissector from Tuexen Michael <Michael.Tuexen@icn.siemens.de>

svn path=/trunk/; revision=2148

1 files changed, 1810 insertions, 0 deletions

diff --git a/packet-sctp.c b/packet-sctp.c
new file mode 100644
index 0000000000..4f5caf3f89
--- /dev/null
+++ b/packet-sctp.c
@@ -0,0 +1,1810 @@
+/* packet-sctp.c
+ * Routines for Stream Control Transmission Protocol dissection
+ * Copyright 2000, Michael Tüxen <Michael.Tuexen@icn.siemens.de>
+ *
+ * $Id: packet-sctp.c,v 1.1 2000/07/21 12:56:58 gram Exp $
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@unicom.net>
+ * Copyright 1998 Gerald Combs
+ *
+ * Copied from README.developer
+ * 
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+
+
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+
+#ifdef HAVE_NETINET_IN_H
+# include <netinet/in.h>
+#endif
+
+#ifdef NEED_SNPRINTF_H
+# ifdef HAVE_STDARG_H
+#  include <stdarg.h>
+# else
+#  include <varargs.h>
+# endif
+# include "snprintf.h"
+#endif
+
+#include <string.h>
+#include <glib.h>
+#include <packet.h>
+
+#include "packet-ip.h"
+
+/* Initialize the protocol and registered fields */
+static int proto_sctp = -1;
+static int hf_sctp_source_port      = -1;
+static int hf_sctp_destination_port = -1;
+static int hf_sctp_verification_tag = -1;
+static int hf_sctp_checksum         = -1;
+
+static int hf_sctp_chunk_type       = -1;
+static int hf_sctp_chunk_flags      = -1;
+static int hf_sctp_chunk_length     = -1;
+
+static int hf_sctp_init_chunk_initiate_tag   = -1;
+static int hf_sctp_init_chunk_adv_rec_window_credit = -1;
+static int hf_sctp_init_chunk_number_of_outbound_streams = -1;
+static int hf_sctp_init_chunk_number_of_inbound_streams  = -1;
+static int hf_sctp_init_chunk_initial_tsn    = -1;
+
+static int hf_sctp_cumulative_tsn_ack = -1;
+
+static int hf_sctp_data_chunk_tsn = -1;
+static int hf_sctp_data_chunk_stream_id = -1;
+static int hf_sctp_data_chunk_stream_seq_number = -1;
+static int hf_sctp_data_chunk_payload_proto_id = -1;
+
+static int hf_sctp_data_chunk_e_bit = -1;
+static int hf_sctp_data_chunk_b_bit = -1;
+static int hf_sctp_data_chunk_u_bit = -1;
+
+static int hf_sctp_sack_chunk_cumulative_tsn_ack = -1;
+static int hf_sctp_sack_chunk_adv_rec_window_credit = -1;
+static int hf_sctp_sack_chunk_number_of_gap_blocks = -1;
+static int hf_sctp_sack_chunk_number_of_dup_tsns = -1;
+static int hf_sctp_sack_chunk_gap_block_start = -1;
+static int hf_sctp_sack_chunk_gap_block_end = -1;
+static int hf_sctp_sack_chunk_duplicate_tsn = -1;
+
+static int hf_sctp_shutdown_chunk_cumulative_tsn_ack = -1;
+
+static int hf_sctp_cwr_chunk_lowest_tsn = -1;
+
+static int hf_sctp_ecne_chunk_lowest_tsn = -1;
+
+static int hf_sctp_shutdown_complete_chunk_t_bit = -1;
+
+static int hf_sctp_chunk_parameter_type = -1;
+static int hf_sctp_chunk_parameter_length = -1;
+static int hf_sctp_parameter_ipv4_address = -1;
+static int hf_sctp_parameter_ipv6_address = -1;
+static int hf_sctp_parameter_cookie_preservative_increment = -1;
+static int hf_sctp_parameter_hostname_hostname = -1;
+static int hf_sctp_supported_address_types_parameter = -1;
+
+static int hf_sctp_cause_code = -1;
+static int hf_sctp_cause_length = -1;
+static int hf_sctp_cause_stream_identifier = -1;
+
+static int hf_sctp_cause_number_of_missing_parameters = -1;
+static int hf_sctp_cause_missing_parameter_type = -1;
+
+static int hf_sctp_cause_measure_of_staleness = -1;
+
+static int hf_sctp_cause_tsn = -1;
+
+/* Initialize the subtree pointers */
+static gint ett_sctp = -1;
+static gint ett_sctp_chunk = -1;
+static gint ett_sctp_chunk_parameter = -1;
+static gint ett_sctp_chunk_cause = -1;
+static gint ett_sctp_data_chunk_flags = -1;
+static gint ett_sctp_sack_chunk_gap_block = -1;
+static gint ett_sctp_supported_address_types_parameter = -1;
+static gint ett_sctp_unrecognized_parameter_parameter = -1;
+
+#define SCTP_DATA_CHUNK_ID               0
+#define SCTP_INIT_CHUNK_ID               1
+#define SCTP_INIT_ACK_CHUNK_ID           2
+#define SCTP_SACK_CHUNK_ID               3
+#define SCTP_HEARTBEAT_CHUNK_ID          4
+#define SCTP_HEARTBEAT_ACK_CHUNK_ID      5
+#define SCTP_ABORT_CHUNK_ID              6
+#define SCTP_SHUTDOWN_CHUNK_ID           7
+#define SCTP_SHUTDOWN_ACK_CHUNK_ID       8
+#define SCTP_ERROR_CHUNK_ID              9
+#define SCTP_COOKIE_ECHO_CHUNK_ID       10
+#define SCTP_COOKIE_ACK_CHUNK_ID        11
+#define SCTP_ECNE_CHUNK_ID              12
+#define SCTP_CWR_CHUNK_ID               13
+#define SCTP_SHUTDOWN_COMPLETE_CHUNK_ID 14
+#define SCTP_IETF_EXT                  255
+
+static const value_string sctp_chunk_type_values[] = {
+  { SCTP_DATA_CHUNK_ID,              "DATA" },
+  { SCTP_INIT_CHUNK_ID,              "INIT" },
+  { SCTP_INIT_ACK_CHUNK_ID,          "INIT ACK" },
+  { SCTP_SACK_CHUNK_ID,              "SACK" },
+  { SCTP_HEARTBEAT_CHUNK_ID,         "HEARTBEAT" },
+  { SCTP_HEARTBEAT_ACK_CHUNK_ID,     "HEARTBEAT ACK" },
+  { SCTP_ABORT_CHUNK_ID,             "ABORT" },
+  { SCTP_SHUTDOWN_CHUNK_ID,          "SHUTDOWN" },
+  { SCTP_SHUTDOWN_ACK_CHUNK_ID,      "SHUTDOWN ACK" },
+  { SCTP_ERROR_CHUNK_ID,             "ERROR" },
+  { SCTP_COOKIE_ECHO_CHUNK_ID,       "COOKIE ECHO" },
+  { SCTP_COOKIE_ACK_CHUNK_ID,        "COOKIE ACK" },
+  { SCTP_ECNE_CHUNK_ID,              "ECNE" },
+  { SCTP_CWR_CHUNK_ID,               "CWR" },
+  { SCTP_SHUTDOWN_COMPLETE_CHUNK_ID, "SHUTDOWN COMPLETE" },
+  { SCTP_IETF_EXT,                   "IETF EXTENSION" },
+  { 0,                               NULL } };
+
+#define HEARTBEAT_INFO_PARAMETER_ID          0x0001
+#define IPV4ADDRESS_PARAMETER_ID             0x0005
+#define IPV6ADDRESS_PARAMETER_ID             0x0006
+#define STATE_COOKIE_PARAMETER_ID            0x0007
+#define UNREC_PARA_PARAMETER_ID              0x0008
+#define COOKIE_PRESERVATIVE_PARAMETER_ID     0x0009
+#define HOSTNAME_ADDRESS_PARAMETER_ID        0x000b
+#define SUPPORTED_ADDRESS_TYPES_PARAMETER_ID 0x000c
+#define ECN_PARAMETER_ID                     0x8000
+
+static const value_string sctp_parameter_identifier_values[] = {
+  { HEARTBEAT_INFO_PARAMETER_ID,          "Heartbeat info" },
+  { IPV4ADDRESS_PARAMETER_ID,             "IPv4 address" },
+  { IPV6ADDRESS_PARAMETER_ID,             "IPv6 address" },
+  { STATE_COOKIE_PARAMETER_ID,            "State cookie" },
+  { UNREC_PARA_PARAMETER_ID,              "Unrecognized parameters" },
+  { COOKIE_PRESERVATIVE_PARAMETER_ID,     "Cookie preservative" },
+  { HOSTNAME_ADDRESS_PARAMETER_ID,        "Hostname address" },
+  { SUPPORTED_ADDRESS_TYPES_PARAMETER_ID, "Supported address types" },
+  { ECN_PARAMETER_ID,                     "ECN" },
+  { 0,                                    NULL } };
+
+#define PARAMETER_TYPE_LENGTH            2
+#define PARAMETER_LENGTH_LENGTH          2
+#define PARAMETER_HEADER_LENGTH          (PARAMETER_TYPE_LENGTH + PARAMETER_LENGTH_LENGTH)
+
+#define PARAMETER_HEADER_OFFSET          0
+#define PARAMETER_TYPE_OFFSET            PARAMETER_HEADER_OFFSET
+#define PARAMETER_LENGTH_OFFSET          (PARAMETER_TYPE_OFFSET + PARAMETER_TYPE_LENGTH)
+#define PARAMETER_VALUE_OFFSET           (PARAMETER_LENGTH_OFFSET + PARAMETER_LENGTH_LENGTH)
+
+#define HEARTBEAT_INFO_PARAMETER_INFO_OFFSET PARAMETER_VALUE_OFFSET
+#define HEARTBEAT_INFO_PARAMETER_HEADER_LENGTH PARAMETER_HEADER_LENGTH
+
+#define IPV4_ADDRESS_LENGTH              4
+#define IPV6_ADDRESS_LENGTH              16
+
+#define STATE_COOKIE_PARAMETER_HEADER_LENGTH   PARAMETER_HEADER_LENGTH
+#define STATE_COOKIE_PARAMETER_COOKIE_OFFSET   PARAMETER_VALUE_OFFSET
+
+#define COOKIE_PRESERVATIVE_PARAMETER_INCR_OFFSET PARAMETER_VALUE_OFFSET
+#define COOKIE_PRESERVATIVE_PARAMETER_INCR_LENGTH 4
+#define SUPPORTED_ADDRESS_TYPE_PARAMETER_ADDRESS_TYPE_LENGTH 2
+
+#define CAUSE_CODE_LENGTH            2
+#define CAUSE_LENGTH_LENGTH          2
+#define CAUSE_HEADER_LENGTH          (CAUSE_CODE_LENGTH + CAUSE_LENGTH_LENGTH)
+
+#define CAUSE_HEADER_OFFSET          0
+#define CAUSE_CODE_OFFSET            CAUSE_HEADER_OFFSET
+#define CAUSE_LENGTH_OFFSET          (CAUSE_CODE_OFFSET + CAUSE_CODE_LENGTH)
+#define CAUSE_INFO_OFFSET            (CAUSE_LENGTH_OFFSET + CAUSE_LENGTH_LENGTH)
+
+#define CAUSE_STREAM_IDENTIFIER_LENGTH 2
+#define CAUSE_RESERVED_LENGTH 2
+#define CAUSE_STREAM_IDENTIFIER_OFFSET CAUSE_INFO_OFFSET
+#define CAUSE_RESERVED_OFFSET          (CAUSE_STREAM_IDENTIFIER_OFFSET + CAUSE_STREAM_IDENTIFIER_LENGTH)
+
+#define CAUSE_NUMBER_OF_MISSING_PARAMETERS_LENGTH 4
+#define CAUSE_MISSING_PARAMETER_TYPE_LENGTH       2
+
+#define CAUSE_NUMBER_OF_MISSING_PARAMETERS_OFFSET CAUSE_INFO_OFFSET
+#define CAUSE_FIRST_MISSING_PARAMETER_TYPE_OFFSET (CAUSE_NUMBER_OF_MISSING_PARAMETERS_OFFSET + \
+                                                   CAUSE_NUMBER_OF_MISSING_PARAMETERS_LENGTH )
+
+#define CAUSE_MEASURE_OF_STALENESS_LENGTH 4
+#define CAUSE_MEASURE_OF_STALENESS_OFFSET CAUSE_INFO_OFFSET
+
+#define CAUSE_TSN_LENGTH 4
+#define CAUSE_TSN_OFFSET CAUSE_INFO_OFFSET
+
+#define INVALID_STREAM_IDENTIFIER              0x01
+#define MISSING_MANDATORY_PARAMETERS           0x02
+#define STALE_COOKIE_ERROR                     0x03
+#define OUT_OF_RESOURCE                        0x04
+#define UNRESOLVABLE_ADDRESS                   0x05
+#define UNRECOGNIZED_CHUNK_TYPE                0x06
+#define INVALID_MANDATORY_PARAMETER            0x07
+#define UNRECOGNIZED_PARAMETERS                0x08
+#define NO_USER_DATA                           0x09
+#define COOKIE_RECEIVED_WHILE_SHUTTING_DOWN    0x0a
+
+static const value_string sctp_cause_code_values[] = {
+  { INVALID_STREAM_IDENTIFIER,           "Invalid stream idetifier" },
+  { MISSING_MANDATORY_PARAMETERS,        "Missing mandator parameter" },
+  { STALE_COOKIE_ERROR,                  "Stale cookie error" },
+  { OUT_OF_RESOURCE,                     "Out of resource" },
+  { UNRESOLVABLE_ADDRESS,                "Unresolvable address" },
+  { UNRECOGNIZED_CHUNK_TYPE,             "Unrecognized chunk type " },
+  { INVALID_MANDATORY_PARAMETER,         "Invalid mandatory parameter" },
+  { UNRECOGNIZED_PARAMETERS,             "Unrecognized parameters" },
+  { NO_USER_DATA,                        "No user data" },
+  { COOKIE_RECEIVED_WHILE_SHUTTING_DOWN, "Cookie received while shutting down" },
+  { 0,                           NULL } };
+
+/* The structure of the common header is described by the following constants */
+#define SOURCE_PORT_LENGTH      2
+#define DESTINATION_PORT_LENGTH 2
+#define VERIFICATION_TAG_LENGTH 4
+#define CHECKSUM_LENGTH         4
+#define COMMON_HEADER_LENGTH    (SOURCE_PORT_LENGTH + \
+				 DESTINATION_PORT_LENGTH + \
+				 VERIFICATION_TAG_LENGTH + \
+				 CHECKSUM_LENGTH)
+#define SOURCE_PORT_OFFSET      0
+#define DESTINATION_PORT_OFFSET (SOURCE_PORT_OFFSET + SOURCE_PORT_LENGTH)
+#define VERIFICATION_TAG_OFFSET (DESTINATION_PORT_OFFSET + DESTINATION_PORT_LENGTH)
+#define CHECKSUM_OFFSET         (VERIFICATION_TAG_OFFSET + VERIFICATION_TAG_LENGTH)
+
+/* The structure of the chunk header is described by the following constants */
+#define CHUNK_TYPE_LENGTH             1
+#define CHUNK_FLAGS_LENGTH            1
+#define CHUNK_LENGTH_LENGTH           2
+#define CHUNK_HEADER_LENGTH           (CHUNK_TYPE_LENGTH + \
+                                       CHUNK_FLAGS_LENGTH + \
+                                       CHUNK_LENGTH_LENGTH)
+#define CHUNK_HEADER_OFFSET           0
+#define CHUNK_TYPE_OFFSET             CHUNK_HEADER_OFFSET
+#define CHUNK_FLAGS_OFFSET            (CHUNK_TYPE_OFFSET + CHUNK_TYPE_LENGTH)
+#define CHUNK_LENGTH_OFFSET           (CHUNK_FLAGS_OFFSET + CHUNK_FLAGS_LENGTH)
+#define CHUNK_VALUE_OFFSET            (CHUNK_LENGTH_OFFSET + CHUNK_LENGTH_LENGTH)
+
+/* The following constants describe the structure of DATA chunks */
+#define DATA_CHUNK_TSN_LENGTH         4
+#define DATA_CHUNK_STREAM_ID_LENGTH   2
+#define DATA_CHUNK_STREAM_SEQ_NUMBER_LENGTH 2
+#define DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH 4
+
+#define DATA_CHUNK_TSN_OFFSET         (CHUNK_VALUE_OFFSET + 0)
+#define DATA_CHUNK_STREAM_ID_OFFSET   (DATA_CHUNK_TSN_OFFSET + DATA_CHUNK_TSN_LENGTH)
+#define DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET (DATA_CHUNK_STREAM_ID_OFFSET + \
+                                             DATA_CHUNK_STREAM_SEQ_NUMBER_LENGTH)
+#define DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET (DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET + \
+                                               DATA_CHUNK_STREAM_SEQ_NUMBER_LENGTH)
+#define DATA_CHUNK_PAYLOAD_OFFSET     (DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET + \
+                                       DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH)
+
+#define DATA_CHUNK_HEADER_LENGTH      (CHUNK_HEADER_LENGTH + \
+                                       DATA_CHUNK_TSN_LENGTH + \
+                                       DATA_CHUNK_STREAM_ID_LENGTH + \
+                                       DATA_CHUNK_STREAM_SEQ_NUMBER_LENGTH + \
+                                       DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH)
+
+#define SCTP_DATA_CHUNK_E_BIT 0x01
+#define SCTP_DATA_CHUNK_B_BIT 0x02
+#define SCTP_DATA_CHUNK_U_BIT 0x04
+
+#define INIT_CHUNK_INITIATE_TAG_LENGTH               4
+#define INIT_CHUNK_ADV_REC_WINDOW_CREDIT_LENGTH      4
+#define INIT_CHUNK_NUMBER_OF_OUTBOUND_STREAMS_LENGTH 2
+#define INIT_CHUNK_NUMBER_OF_INBOUND_STREAMS_LENGTH  2
+#define INIT_CHUNK_INITIAL_TSN_LENGTH                4
+
+#define INIT_CHUNK_INITIATE_TAG_OFFSET               CHUNK_VALUE_OFFSET
+#define INIT_CHUNK_ADV_REC_WINDOW_CREDIT_OFFSET      (INIT_CHUNK_INITIATE_TAG_OFFSET + \
+                                                      INIT_CHUNK_INITIATE_TAG_LENGTH )
+#define INIT_CHUNK_NUMBER_OF_OUTBOUND_STREAMS_OFFSET (INIT_CHUNK_ADV_REC_WINDOW_CREDIT_OFFSET + \
+                                                      INIT_CHUNK_ADV_REC_WINDOW_CREDIT_LENGTH )
+#define INIT_CHUNK_NUMBER_OF_INBOUND_STREAMS_OFFSET  (INIT_CHUNK_NUMBER_OF_OUTBOUND_STREAMS_OFFSET + \
+                                                      INIT_CHUNK_NUMBER_OF_OUTBOUND_STREAMS_LENGTH )
+#define INIT_CHUNK_INITIAL_TSN_OFFSET                (INIT_CHUNK_NUMBER_OF_INBOUND_STREAMS_OFFSET + \
+                                                      INIT_CHUNK_NUMBER_OF_INBOUND_STREAMS_LENGTH )
+#define INIT_CHUNK_VARIABLE_LENGTH_PARAMETER_OFFSET  (INIT_CHUNK_INITIAL_TSN_OFFSET + \
+                                                      INIT_CHUNK_INITIAL_TSN_LENGTH )
+
+
+#define SACK_CHUNK_CUMULATIVE_TSN_ACK_LENGTH    4
+#define SACK_CHUNK_ADV_REC_WINDOW_CREDIT_LENGTH 4
+#define SACK_CHUNK_NUMBER_OF_GAP_BLOCKS_LENGTH  2
+#define SACK_CHUNK_NUMBER_OF_DUP_TSNS_LENGTH    2
+#define SACK_CHUNK_GAP_BLOCK_LENGTH             4
+#define SACK_CHUNK_GAP_BLOCK_START_LENGTH       2
+#define SACK_CHUNK_GAP_BLOCK_END_LENGTH         2
+#define SACK_CHUNK_DUP_TSN_LENGTH               4
+
+#define SACK_CHUNK_CUMULATIVE_TSN_ACK_OFFSET (CHUNK_VALUE_OFFSET + 0)
+#define SACK_CHUNK_ADV_REC_WINDOW_CREDIT_OFFSET (SACK_CHUNK_CUMULATIVE_TSN_ACK_OFFSET + \
+                                                 SACK_CHUNK_CUMULATIVE_TSN_ACK_LENGTH)
+#define SACK_CHUNK_NUMBER_OF_GAP_BLOCKS_OFFSET (SACK_CHUNK_ADV_REC_WINDOW_CREDIT_OFFSET + \
+                                                SACK_CHUNK_ADV_REC_WINDOW_CREDIT_LENGTH)
+#define SACK_CHUNK_NUMBER_OF_DUP_TSNS_OFFSET (SACK_CHUNK_NUMBER_OF_GAP_BLOCKS_OFFSET + \
+                                              SACK_CHUNK_NUMBER_OF_GAP_BLOCKS_LENGTH)
+#define SACK_CHUNK_GAP_BLOCK_OFFSET (SACK_CHUNK_NUMBER_OF_DUP_TSNS_OFFSET + \
+                                     SACK_CHUNK_NUMBER_OF_DUP_TSNS_LENGTH)
+
+#define HEARTBEAT_CHUNK_INFO_OFFSET CHUNK_VALUE_OFFSET
+
+#define SHUTDOWN_CHUNK_CUMULATIVE_TSN_ACK_OFFSET CHUNK_VALUE_OFFSET
+#define SHUTDOWN_CHUNK_CUMULATIVE_TSN_ACK_LENGTH 4
+		
+#define ABORT_CHUNK_FIRST_ERROR_CAUSE_OFFSET 4     
+#define ERROR_CHUNK_FIRST_ERROR_CAUSE_OFFSET 4     
+
+#define COOKIE_ECHO_CHUNK_COOKIE_OFFSET CHUNK_VALUE_OFFSET
+
+#define ECNE_CHUNK_LOWEST_TSN_OFFSET CHUNK_VALUE_OFFSET
+#define ECNE_CHUNK_LOWEST_TSN_LENGTH 4
+
+#define CWR_CHUNK_LOWEST_TSN_OFFSET CHUNK_VALUE_OFFSET
+#define CWR_CHUNK_LOWEST_TSN_LENGTH 4
+		     
+#define SCTP_SHUTDOWN_COMPLETE_CHUNK_T_BIT 0x01
+
+static const true_false_string sctp_data_chunk_e_bit_value = {
+  "Last segment",
+  "Not the last segment"
+};
+
+static const true_false_string sctp_data_chunk_b_bit_value = {
+  "First segment",
+  "Subsequent segment"
+};
+
+static const true_false_string sctp_data_chunk_u_bit_value = {
+  "Unordered delivery",
+  "Ordered deliviery"
+};
+
+static const true_false_string sctp_shutdown_complete_chunk_t_bit_value = {
+  "No TCB destroyed",
+  "TCB destroyed"
+};
+
+/* adler32.c -- compute the Adler-32 checksum of a data stream
+ * Copyright (C) 1995-1996 Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ * available, e.g. from  http://www.cdrom.com/pub/infozip/zlib/
+ *
+ * It was modified for the use in this dissector.
+ */
+
+#define BASE 65521L /* largest prime smaller than 65536      */
+#define NMAX 5540   /* NMAX is the largest n - 12 such that  */
+		    /* 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
+
+#define DO1(buf,i)  {s1 += buf[i]; s2 += s1;}
+#define DO2(buf,i)  DO1(buf,i); DO1(buf,i+1);
+#define DO4(buf,i)  DO2(buf,i); DO2(buf,i+2);
+#define DO8(buf,i)  DO4(buf,i); DO4(buf,i+4);
+#define DO16(buf)   DO8(buf,0); DO8(buf,8);
+
+unsigned int sctp_adler_32(const unsigned char* buf,
+			         unsigned int len)
+{
+    unsigned int s1 = 1L;
+    unsigned int s2 = 0L;
+    int k;
+    
+    /* handle the first 8 bytes of the datagram */
+    DO8(buf,0);
+    buf += SOURCE_PORT_LENGTH + 
+           DESTINATION_PORT_LENGTH + 
+           VERIFICATION_TAG_LENGTH;
+    
+    /* handle four 0 bytes as checksum */
+    s2  += CHECKSUM_LENGTH * s1;
+    buf += CHECKSUM_LENGTH;
+
+    /* now we have 12 bytes handled */
+    len -= COMMON_HEADER_LENGTH;
+
+    /* handle the rest of the datagram */
+    while (len > 0) {
+        k = len < NMAX ? len : NMAX;
+        len -= k;
+        while (k >= 16) {
+            DO16(buf);
+            buf += 16;
+            k -= 16;
+        }
+        if (k != 0) do {
+            s1 += *buf++;
+            s2 += s1;
+        } while (--k);
+        s1 %= BASE;
+        s2 %= BASE;
+    }
+    return (s2 << 16) | s1;
+}
+
+static char *sctp_checksum_state(tvbuff_t *tvb, guint orig_checksum)
+{
+  guint length;
+  
+  length = tvb_length(tvb);
+  if (orig_checksum == sctp_adler_32(tvb_get_ptr(tvb, 0, length), length))
+    return "correct";
+  else
+    return "incorrect";
+}
+
+guint 
+nr_of_padding_bytes (guint length)
+{
+  guint remainder;
+
+  remainder = length % 4;
+
+  if (remainder == 0)
+    return 0;
+  else
+    return 4 - remainder;
+}
+
+/* 
+ * TLV parameter stuff for INIT and INIT-ACK chunks
+ */
+
+void
+dissect_parameter(tvbuff_t *, proto_tree *);
+
+void
+dissect_sctp_chunk(tvbuff_t *, proto_tree *);
+
+void dissect_tlv_parameter_list(tvbuff_t *parameter_list_tvb, proto_tree *tree)
+{
+  guint offset, length, padding_length, total_length;
+  tvbuff_t *parameter_tvb;
+
+  offset = 0;
+  while(tvb_length_remaining(parameter_list_tvb, offset)) {
+    length         = tvb_get_ntohs(parameter_list_tvb, offset + PARAMETER_LENGTH_OFFSET);
+    padding_length = nr_of_padding_bytes(length);
+    total_length   = length + padding_length;
+    /* create a tvb for the chunk including the padding bytes */
+    parameter_tvb    = tvb_new_subset(parameter_list_tvb, offset, total_length, total_length);
+    dissect_parameter(parameter_tvb, tree); 
+    /* get rid of the handled parameter */
+    offset += total_length;
+  }
+}
+
+void
+dissect_heartbeat_info_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+  guint16 length, heartbeat_info_length;
+  
+  length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET);
+  
+  heartbeat_info_length = length - HEARTBEAT_INFO_PARAMETER_HEADER_LENGTH;
+
+  proto_tree_add_text(parameter_tree, parameter_tvb, HEARTBEAT_INFO_PARAMETER_INFO_OFFSET, heartbeat_info_length,
+		      "Heartbeat info (%u byte%s)",
+		      heartbeat_info_length, plurality(heartbeat_info_length, "", "s"));
+
+  proto_item_set_text(parameter_item, "Heartbeat info parameter with %u byte%s of info",
+		      heartbeat_info_length, plurality(heartbeat_info_length, "", "s"));
+}
+
+void
+dissect_ipv4_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+  guint32 ipv4_address;
+
+  tvb_memcpy(parameter_tvb, (guint8 *)&ipv4_address, PARAMETER_VALUE_OFFSET, IPV4_ADDRESS_LENGTH); 
+  proto_tree_add_ipv4(parameter_tree, hf_sctp_parameter_ipv4_address,
+		      parameter_tvb, PARAMETER_VALUE_OFFSET, IPV4_ADDRESS_LENGTH,
+		      ipv4_address);  
+  proto_item_set_text(parameter_item, "IPV4 address parameter");
+}
+
+void
+dissect_ipv6_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+  proto_tree_add_ipv6(parameter_tree, hf_sctp_parameter_ipv6_address,
+		      parameter_tvb, PARAMETER_VALUE_OFFSET, IPV6_ADDRESS_LENGTH,
+		      tvb_get_ptr(parameter_tvb, PARAMETER_VALUE_OFFSET, IPV6_ADDRESS_LENGTH));
+  
+  proto_item_set_text(parameter_item, "IPV6 address parameter");
+}
+
+void
+dissect_state_cookie_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+  guint16 length, state_cookie_length;
+  
+  length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET);
+  
+  state_cookie_length = length - STATE_COOKIE_PARAMETER_HEADER_LENGTH;
+
+  proto_tree_add_text(parameter_tree, parameter_tvb, STATE_COOKIE_PARAMETER_COOKIE_OFFSET, state_cookie_length,
+		      "State cookie (%u byte%s)",
+		      state_cookie_length, plurality(state_cookie_length, "", "s"));
+
+  proto_item_set_text(parameter_item, "State Cookie Parameter with %u byte%s cookie",
+		      state_cookie_length, plurality(state_cookie_length, "", "s"));
+}
+
+void
+dissect_unrecognized_parameters_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+  guint16 length, parameter_value_length;
+  tvbuff_t *unrecognized_parameters_tvb;
+
+  length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET);
+  
+  parameter_value_length = length - PARAMETER_HEADER_LENGTH;
+
+  unrecognized_parameters_tvb = tvb_new_subset(parameter_tvb, PARAMETER_VALUE_OFFSET, 
+					       parameter_value_length, parameter_value_length);
+  dissect_tlv_parameter_list(unrecognized_parameters_tvb, parameter_tree);
+   
+  proto_item_set_text(parameter_item, "Unrecognized parameter of type");
+}
+
+void
+dissect_cookie_preservative_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+  guint32 increment;
+
+  increment =  tvb_get_ntohl(parameter_tvb, COOKIE_PRESERVATIVE_PARAMETER_INCR_OFFSET);
+  
+  proto_tree_add_uint(parameter_tree, hf_sctp_parameter_cookie_preservative_increment, parameter_tvb, 
+		      COOKIE_PRESERVATIVE_PARAMETER_INCR_OFFSET, 
+		      COOKIE_PRESERVATIVE_PARAMETER_INCR_LENGTH,
+		      increment);
+  
+  proto_item_set_text(parameter_item, "Cookie preservative parameter requesting for a %u msec increment",
+		      increment);
+}
+
+void
+dissect_hostname_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+  guint16  length, hostname_length;
+  char *hostname;
+
+  length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET);
+  
+  hostname_length = length - PARAMETER_HEADER_LENGTH;
+  hostname = (char *)tvb_get_ptr(parameter_tvb, PARAMETER_VALUE_OFFSET, hostname_length);
+  proto_tree_add_string(parameter_tree, hf_sctp_parameter_hostname_hostname, parameter_tvb,
+			PARAMETER_VALUE_OFFSET, hostname_length,
+			hostname);
+
+  proto_item_set_text(parameter_item, "Hostname parameter");
+}
+
+void
+dissect_supported_address_types_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+  guint16 length, address_type, number_of_address_types, address_type_number, list_of_address_types_length ;
+  guint offset;
+  proto_item *address_list_item;
+  proto_tree *address_list_tree;
+
+  length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET);
+  list_of_address_types_length = length - PARAMETER_HEADER_LENGTH;
+  number_of_address_types = list_of_address_types_length / SUPPORTED_ADDRESS_TYPE_PARAMETER_ADDRESS_TYPE_LENGTH;
+
+  address_list_item = proto_tree_add_text(parameter_tree, parameter_tvb, PARAMETER_VALUE_OFFSET, list_of_address_types_length,
+					  "Supported Address Types (%u address type%s)",
+					  number_of_address_types, plurality(number_of_address_types, "", "s"));
+  address_list_tree = proto_item_add_subtree(address_list_item, ett_sctp_supported_address_types_parameter);
+ 
+  offset = PARAMETER_VALUE_OFFSET;
+  for(address_type_number = 1; address_type_number <= number_of_address_types; address_type_number++) {
+    address_type = tvb_get_ntohs(parameter_tvb, offset);
+    proto_tree_add_uint_format(address_list_tree, hf_sctp_supported_address_types_parameter,
+			       parameter_tvb, offset, SUPPORTED_ADDRESS_TYPE_PARAMETER_ADDRESS_TYPE_LENGTH,
+			       address_type, "Supported address type: %u (%s)",
+			       address_type, val_to_str(address_type, sctp_parameter_identifier_values, "unknown"));
+    offset += SUPPORTED_ADDRESS_TYPE_PARAMETER_ADDRESS_TYPE_LENGTH;
+  };
+
+  proto_item_set_text(parameter_item, "Supported address types parameter reporting %u address type%s",
+		      number_of_address_types, plurality(number_of_address_types, "", "s"));
+}
+
+void
+dissect_ecn_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+   proto_item_set_text(parameter_item, "ECN parameter");
+}
+
+void
+dissect_unknown_parameter(tvbuff_t *parameter_tvb, proto_tree *parameter_tree, proto_item *parameter_item)
+{
+  guint16 type, length, parameter_value_length;
+  
+  type   = tvb_get_ntohs(parameter_tvb, PARAMETER_TYPE_OFFSET);
+  length = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET);
+  
+  parameter_value_length = length - PARAMETER_HEADER_LENGTH;
+
+  proto_tree_add_text(parameter_tree, parameter_tvb, PARAMETER_VALUE_OFFSET, parameter_value_length,
+		      "Parameter value (%u byte%s)",
+		      parameter_value_length, plurality(parameter_value_length, "", "s"));
+
+  proto_item_set_text(parameter_item, "Parameter of type %u and %u byte%s value",
+		      type, parameter_value_length, plurality(parameter_value_length, "", "s"));
+}
+
+void
+dissect_parameter(tvbuff_t *parameter_tvb, proto_tree *chunk_tree)
+{
+  guint16 type, length, padding_length, total_length;
+  proto_item *parameter_item;
+  proto_tree *parameter_tree;
+
+  type           = tvb_get_ntohs(parameter_tvb, PARAMETER_TYPE_OFFSET);
+  length         = tvb_get_ntohs(parameter_tvb, PARAMETER_LENGTH_OFFSET);
+  padding_length = nr_of_padding_bytes(length);
+  total_length   = length + padding_length;
+   
+  parameter_item = proto_tree_add_notext(chunk_tree, parameter_tvb, PARAMETER_HEADER_OFFSET, total_length);
+  parameter_tree = proto_item_add_subtree(parameter_item, ett_sctp_chunk_parameter);
+ 
+  proto_tree_add_uint_format(parameter_tree, hf_sctp_chunk_parameter_type, 
+			     parameter_tvb, PARAMETER_TYPE_OFFSET, PARAMETER_TYPE_LENGTH,
+			     type, "Parameter type: %u (%s)",
+			     type, val_to_str(type, sctp_parameter_identifier_values, "unknown"));
+  proto_tree_add_uint(parameter_tree, hf_sctp_chunk_parameter_length, 
+		      parameter_tvb, PARAMETER_LENGTH_OFFSET, PARAMETER_LENGTH_LENGTH,
+		      length);
+ 
+  switch(type) {
+  case HEARTBEAT_INFO_PARAMETER_ID:
+    dissect_heartbeat_info_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  case IPV4ADDRESS_PARAMETER_ID:
+    dissect_ipv4_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  case IPV6ADDRESS_PARAMETER_ID:
+    dissect_ipv6_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  case STATE_COOKIE_PARAMETER_ID:
+    dissect_state_cookie_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  case UNREC_PARA_PARAMETER_ID:
+    dissect_unrecognized_parameters_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  case COOKIE_PRESERVATIVE_PARAMETER_ID:
+    dissect_cookie_preservative_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  case HOSTNAME_ADDRESS_PARAMETER_ID:
+    dissect_hostname_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  case SUPPORTED_ADDRESS_TYPES_PARAMETER_ID:
+    dissect_supported_address_types_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  case ECN_PARAMETER_ID:
+    dissect_ecn_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  default:
+    dissect_unknown_parameter(parameter_tvb, parameter_tree, parameter_item);
+    break;
+  };
+  if (padding_length > 0)
+    proto_tree_add_text(parameter_tree, parameter_tvb, PARAMETER_HEADER_OFFSET + length, padding_length,
+			"Padding: %u byte%s",
+			padding_length, plurality(padding_length, "", "s"));
+}
+
+/*
+ * Code to handle error causes for ABORT and ERROR chunks
+ */
+void
+dissect_invalid_stream_identifier_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  guint16 stream_identifier;
+
+  stream_identifier   = tvb_get_ntohs(cause_tvb, CAUSE_STREAM_IDENTIFIER_OFFSET);
+  proto_tree_add_uint(cause_tree, hf_sctp_cause_stream_identifier, 
+		      cause_tvb, CAUSE_STREAM_IDENTIFIER_OFFSET, CAUSE_STREAM_IDENTIFIER_LENGTH,
+		      stream_identifier);
+  proto_tree_add_text(cause_tree, cause_tvb, CAUSE_RESERVED_OFFSET, CAUSE_RESERVED_LENGTH,
+		      "Reserved (2 bytes)");
+
+  proto_item_set_text(cause_item, "Error cause reporting invalid stream identifier %u",
+		      stream_identifier);
+}
+
+void
+dissect_missing_mandatory_parameters_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  guint32 number_of_missing_parameters, missing_parameter_number;
+  guint16 parameter_type;
+  guint   offset;
+
+  number_of_missing_parameters = tvb_get_ntohl(cause_tvb, CAUSE_NUMBER_OF_MISSING_PARAMETERS_OFFSET);
+  proto_tree_add_uint(cause_tree, hf_sctp_cause_number_of_missing_parameters, 
+		      cause_tvb, CAUSE_NUMBER_OF_MISSING_PARAMETERS_OFFSET, CAUSE_NUMBER_OF_MISSING_PARAMETERS_LENGTH,
+		      number_of_missing_parameters);
+  offset = CAUSE_FIRST_MISSING_PARAMETER_TYPE_OFFSET;
+  for(missing_parameter_number = 1; missing_parameter_number <= number_of_missing_parameters; missing_parameter_number++) {
+    parameter_type = tvb_get_ntohs(cause_tvb, offset);
+    proto_tree_add_uint_format(cause_tree, hf_sctp_cause_missing_parameter_type,
+			       cause_tvb, offset, CAUSE_MISSING_PARAMETER_TYPE_LENGTH,
+			       parameter_type, "Missing parameter type: %u (%s)",
+			       parameter_type, 
+			       val_to_str(parameter_type, sctp_parameter_identifier_values, "unknown"));
+    offset +=  CAUSE_MISSING_PARAMETER_TYPE_LENGTH;
+  };
+
+  proto_item_set_text(cause_item, "Error cause reporting %u missing mandatory parameter%s",
+		      number_of_missing_parameters, plurality(number_of_missing_parameters, "", "s") );
+}
+
+void
+dissect_stale_cookie_error_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  guint32 measure_of_staleness;
+
+  measure_of_staleness =  tvb_get_ntohl(cause_tvb, CAUSE_MEASURE_OF_STALENESS_OFFSET);
+  
+  proto_tree_add_uint(cause_tree, hf_sctp_cause_measure_of_staleness, cause_tvb, 
+		      CAUSE_MEASURE_OF_STALENESS_OFFSET, 
+		      CAUSE_MEASURE_OF_STALENESS_LENGTH,
+		      measure_of_staleness);
+  
+  proto_item_set_text(cause_item, "Error cause reporting a measure of staleness of %u usec",
+		      measure_of_staleness);
+}
+
+void
+dissect_out_of_resource_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  proto_item_set_text(cause_item, "Error cause reporting lack of resources");
+}
+
+void
+dissect_unresolvable_address_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  guint16 code, length, parameter_length, parameter_type;
+  tvbuff_t *parameter_tvb;
+
+  code   = tvb_get_ntohs(cause_tvb, CAUSE_CODE_OFFSET);
+  length = tvb_get_ntohs(cause_tvb, CAUSE_LENGTH_OFFSET);
+  
+  parameter_length = length - CAUSE_HEADER_LENGTH;
+  parameter_tvb = tvb_new_subset(cause_tvb, CAUSE_INFO_OFFSET, 
+				 parameter_length, parameter_length);
+
+  dissect_parameter(parameter_tvb, cause_tree);
+  parameter_type = tvb_get_ntohs(parameter_tvb, PARAMETER_TYPE_OFFSET);
+ 
+  proto_item_set_text(cause_item, "Error cause reporting unresolvable address of type %u (%s)",
+		      parameter_type, val_to_str(parameter_type, sctp_parameter_identifier_values, "unknown") );
+}
+
+void
+dissect_unrecognized_chunk_type_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  guint16 length, chunk_length;
+  guint8 unrecognized_type;
+  tvbuff_t *unrecognized_chunk_tvb;
+
+  length = tvb_get_ntohs(cause_tvb, CAUSE_LENGTH_OFFSET);
+  
+  chunk_length = length - CAUSE_HEADER_LENGTH;
+
+  unrecognized_chunk_tvb = tvb_new_subset(cause_tvb, CAUSE_INFO_OFFSET, 
+					  chunk_length, chunk_length);
+  dissect_sctp_chunk(unrecognized_chunk_tvb, cause_tree);
+
+  unrecognized_type   = tvb_get_guint8(unrecognized_chunk_tvb, CHUNK_TYPE_OFFSET);
+ 
+  proto_item_set_text(cause_item, "Error cause reporting unrecognized chunk of type %u (%s)",
+		      unrecognized_type,
+		      val_to_str(unrecognized_type, sctp_chunk_type_values, "unknown"));
+}
+
+void
+dissect_invalid_mandatory_parameter_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  proto_item_set_text(cause_item, "Error cause reporting an invalid mandatory parameter");
+}
+
+void
+dissect_unrecognized_parameters_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  guint16 length, cause_info_length;
+  tvbuff_t *unrecognized_parameters_tvb;
+
+  length = tvb_get_ntohs(cause_tvb, CAUSE_LENGTH_OFFSET);
+  
+  cause_info_length = length - CAUSE_HEADER_LENGTH;
+
+  unrecognized_parameters_tvb = tvb_new_subset(cause_tvb, CAUSE_INFO_OFFSET, 
+					       cause_info_length, cause_info_length);
+  dissect_tlv_parameter_list(unrecognized_parameters_tvb, cause_tree);
+ 
+  proto_item_set_text(cause_item, "Error cause reporting unrecognized parameters");
+}
+
+void
+dissect_no_user_data_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  guint32 tsn;
+
+  tsn = tvb_get_ntohl(cause_tvb, CAUSE_TSN_OFFSET);
+  proto_tree_add_uint(cause_tree, hf_sctp_cause_tsn, cause_tvb, 
+		      CAUSE_TSN_OFFSET, 
+		      CAUSE_TSN_LENGTH,
+		      tsn);
+
+  proto_item_set_text(cause_item, "Error cause reporting data chunk with TSN %u contains no data",
+		      tsn);
+}
+
+void
+dissect_cookie_received_while_shutting_down_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  proto_item_set_text(cause_item, "Error cause reporting cookie reception while shutting down");
+}
+
+void
+dissect_unknown_cause(tvbuff_t *cause_tvb, proto_tree *cause_tree, proto_item *cause_item)
+{
+  guint16 code, length, cause_info_length;
+
+  code   = tvb_get_ntohs(cause_tvb, CAUSE_CODE_OFFSET);
+  length = tvb_get_ntohs(cause_tvb, CAUSE_LENGTH_OFFSET);
+  
+  cause_info_length = length - CAUSE_HEADER_LENGTH;
+
+  proto_tree_add_text(cause_tree, cause_tvb, CAUSE_INFO_OFFSET, cause_info_length,
+		      "Cause specific information (%u byte%s)",
+		      cause_info_length, plurality(cause_info_length, "", "s"));
+
+  proto_item_set_text(cause_item, "Error cause with code %u and %u byte%s information",
+		      code, cause_info_length, plurality(cause_info_length, "", "s"));
+}
+
+void
+dissect_error_cause(tvbuff_t *cause_tvb, proto_tree *chunk_tree)
+{
+  guint16 code, length, padding_length, total_length;
+  proto_item *cause_item;
+  proto_tree *cause_tree;
+
+  code           = tvb_get_ntohs(cause_tvb, CAUSE_CODE_OFFSET);
+  length         = tvb_get_ntohs(cause_tvb, CAUSE_LENGTH_OFFSET);
+  padding_length = nr_of_padding_bytes(length);
+  total_length   = length + padding_length;
+  
+  cause_item = proto_tree_add_notext(chunk_tree, cause_tvb, CAUSE_HEADER_OFFSET, total_length);
+  proto_item_set_text(cause_item, "BAD ERROR CAUSE");
+  cause_tree = proto_item_add_subtree(cause_item, ett_sctp_chunk_cause);
+ 
+  proto_tree_add_uint_format(cause_tree, hf_sctp_cause_code, 
+			     cause_tvb, CAUSE_CODE_OFFSET, CAUSE_CODE_LENGTH,
+			     code, "Cause code: %u (%s)",
+			     code, val_to_str(code, sctp_cause_code_values, "unknown"));
+  proto_tree_add_uint(cause_tree, hf_sctp_cause_length, 
+		      cause_tvb, CAUSE_LENGTH_OFFSET, CAUSE_LENGTH_LENGTH,
+		      length);
+ 
+  switch(code) {
+  case INVALID_STREAM_IDENTIFIER:
+    dissect_invalid_stream_identifier_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  case MISSING_MANDATORY_PARAMETERS:
+    dissect_missing_mandatory_parameters_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  case STALE_COOKIE_ERROR:
+    dissect_stale_cookie_error_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  case OUT_OF_RESOURCE:
+    dissect_out_of_resource_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  case UNRESOLVABLE_ADDRESS:
+    dissect_unresolvable_address_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  case UNRECOGNIZED_CHUNK_TYPE:
+    dissect_unrecognized_chunk_type_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  case INVALID_MANDATORY_PARAMETER:
+    dissect_invalid_mandatory_parameter_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  case UNRECOGNIZED_PARAMETERS:
+    dissect_unrecognized_parameters_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  case NO_USER_DATA:
+    dissect_no_user_data_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  case COOKIE_RECEIVED_WHILE_SHUTTING_DOWN:
+    dissect_cookie_received_while_shutting_down_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  default:
+    dissect_unknown_cause(cause_tvb, cause_tree, cause_item);
+    break;
+  };
+  if (padding_length > 0)
+    proto_tree_add_text(cause_tree, cause_tvb, CAUSE_HEADER_OFFSET + length, padding_length,
+			"Padding: %u byte%s",
+			padding_length, plurality(padding_length, "", "s"));
+}
+
+/*
+ * Code to actually dissect the packets 
+*/
+
+void
+dissect_data_chunk(tvbuff_t *chunk_tvb,
+		   proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint8  flags;
+  guint16 length, payload_length, padding_length, stream_id, stream_seq_number;
+  guint32 tsn, payload_proto_id;
+  proto_tree *flag_tree;
+
+  flags             = tvb_get_guint8(chunk_tvb, CHUNK_FLAGS_OFFSET);
+  length            = tvb_get_ntohs(chunk_tvb, CHUNK_LENGTH_OFFSET);
+   
+  flag_tree = proto_item_add_subtree(flags_item, ett_sctp_data_chunk_flags);
+  proto_tree_add_boolean(flag_tree, hf_sctp_data_chunk_e_bit, chunk_tvb,
+			 CHUNK_FLAGS_OFFSET, CHUNK_FLAGS_LENGTH, flags);
+  proto_tree_add_boolean(flag_tree, hf_sctp_data_chunk_b_bit, chunk_tvb,
+			 CHUNK_FLAGS_OFFSET, CHUNK_FLAGS_LENGTH, flags);
+  proto_tree_add_boolean(flag_tree, hf_sctp_data_chunk_u_bit, chunk_tvb,
+			 CHUNK_FLAGS_OFFSET, CHUNK_FLAGS_LENGTH, flags);
+
+  tsn               = tvb_get_ntohl(chunk_tvb, DATA_CHUNK_TSN_OFFSET);
+  stream_id         = tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_ID_OFFSET);
+  stream_seq_number = tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET);
+  payload_proto_id  = tvb_get_ntohl(chunk_tvb, DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET);
+  
+  payload_length = length - DATA_CHUNK_HEADER_LENGTH;
+  padding_length = nr_of_padding_bytes(length);
+
+  proto_tree_add_uint(chunk_tree, hf_sctp_data_chunk_tsn, 
+		      chunk_tvb,
+		      DATA_CHUNK_TSN_OFFSET, DATA_CHUNK_TSN_LENGTH,
+		      tsn);
+  proto_tree_add_uint(chunk_tree, hf_sctp_data_chunk_stream_id, 
+		      chunk_tvb, 
+		      DATA_CHUNK_STREAM_ID_OFFSET, DATA_CHUNK_STREAM_ID_LENGTH,
+		      stream_id);
+  proto_tree_add_uint(chunk_tree, hf_sctp_data_chunk_stream_seq_number, 
+		      chunk_tvb, 
+		      DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET, DATA_CHUNK_STREAM_SEQ_NUMBER_LENGTH,
+		      stream_seq_number);
+  proto_tree_add_uint(chunk_tree, hf_sctp_data_chunk_payload_proto_id, 
+		      chunk_tvb,
+		      DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET, DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH,
+		      payload_proto_id);
+  proto_tree_add_text(chunk_tree, chunk_tvb, DATA_CHUNK_PAYLOAD_OFFSET, payload_length,
+		      "Payload (%u byte%s)",
+		      payload_length, plurality(payload_length, "", "s")); 
+  if (padding_length > 0)
+    proto_tree_add_text(chunk_tree, chunk_tvb, CHUNK_HEADER_OFFSET + length, padding_length,
+			"Padding: %u byte%s",
+			padding_length, plurality(padding_length, "", "s"));
+  
+  proto_item_set_text(chunk_item, "DATA chunk with TSN %u (%u:%u) containing %u byte%s of payload",
+		      tsn, stream_id, stream_seq_number, 
+		      payload_length, plurality(payload_length, "", "s"));
+} 
+
+void
+dissect_init_chunk(tvbuff_t *chunk_tvb, 
+		   proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint32 initiate_tag, adv_rec_window_credit, initial_tsn;
+  guint16 number_of_inbound_streams, number_of_outbound_streams;
+  guint8  type;
+  tvbuff_t *parameter_list_tvb;
+
+  type                       = tvb_get_guint8(chunk_tvb, CHUNK_TYPE_OFFSET);
+ 
+  initiate_tag               = tvb_get_ntohl(chunk_tvb, INIT_CHUNK_INITIATE_TAG_OFFSET);
+  adv_rec_window_credit      = tvb_get_ntohl(chunk_tvb, INIT_CHUNK_ADV_REC_WINDOW_CREDIT_OFFSET);
+  number_of_inbound_streams  = tvb_get_ntohs(chunk_tvb, INIT_CHUNK_NUMBER_OF_INBOUND_STREAMS_OFFSET);
+  number_of_outbound_streams = tvb_get_ntohs(chunk_tvb, INIT_CHUNK_NUMBER_OF_OUTBOUND_STREAMS_OFFSET);
+  initial_tsn                = tvb_get_ntohl(chunk_tvb, INIT_CHUNK_INITIAL_TSN_OFFSET);
+
+  /* handle fixed parameters */
+  proto_tree_add_uint(chunk_tree, hf_sctp_init_chunk_initiate_tag, 
+		      chunk_tvb,
+		      INIT_CHUNK_INITIATE_TAG_OFFSET, INIT_CHUNK_INITIATE_TAG_LENGTH,
+		      initiate_tag);
+  proto_tree_add_uint(chunk_tree, hf_sctp_init_chunk_adv_rec_window_credit, 
+		      chunk_tvb,
+		      INIT_CHUNK_ADV_REC_WINDOW_CREDIT_OFFSET, INIT_CHUNK_ADV_REC_WINDOW_CREDIT_LENGTH,
+		      adv_rec_window_credit);
+  proto_tree_add_uint(chunk_tree, hf_sctp_init_chunk_number_of_outbound_streams, 
+		      chunk_tvb,
+		      INIT_CHUNK_NUMBER_OF_OUTBOUND_STREAMS_OFFSET, INIT_CHUNK_NUMBER_OF_OUTBOUND_STREAMS_LENGTH,
+		      number_of_outbound_streams);
+  proto_tree_add_uint(chunk_tree, hf_sctp_init_chunk_number_of_inbound_streams, 
+		      chunk_tvb,
+		      INIT_CHUNK_NUMBER_OF_INBOUND_STREAMS_OFFSET, INIT_CHUNK_NUMBER_OF_INBOUND_STREAMS_LENGTH,
+		      number_of_inbound_streams);
+  proto_tree_add_uint(chunk_tree, hf_sctp_init_chunk_initial_tsn, 
+		      chunk_tvb,
+		      INIT_CHUNK_INITIAL_TSN_OFFSET, INIT_CHUNK_INITIAL_TSN_LENGTH,
+		      initial_tsn);
+  
+  /* handle variable paramters */
+  parameter_list_tvb = tvb_new_subset(chunk_tvb, INIT_CHUNK_VARIABLE_LENGTH_PARAMETER_OFFSET, -1, -1);
+  dissect_tlv_parameter_list(parameter_list_tvb, chunk_tree);
+
+  proto_item_set_text(chunk_item, 
+		      "%s chunk requesting for %u outbound stream%s and accepting up to %u inbound stream%s",
+		      val_to_str(type, sctp_chunk_type_values, "unknown"),
+		      number_of_outbound_streams, plurality(number_of_outbound_streams, "", "s"),
+		      number_of_inbound_streams, plurality(number_of_inbound_streams, "", "s"));
+} 
+
+void
+dissect_init_ack_chunk(tvbuff_t *chunk_tvb, 
+		       proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  dissect_init_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+} 
+
+void
+dissect_sack_chunk(tvbuff_t *chunk_tvb, 
+		   proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint32 cumulative_tsn_ack, adv_rec_window_credit, dup_tsn;
+  guint16 number_of_gap_blocks, number_of_dup_tsns;
+  guint16 gap_block_number, dup_tsn_number, start, end;
+  gint gap_block_offset, dup_tsn_offset;
+  proto_item *block_item;
+  proto_tree *block_tree;
+
+  cumulative_tsn_ack    = tvb_get_ntohl(chunk_tvb, SACK_CHUNK_CUMULATIVE_TSN_ACK_OFFSET);
+  adv_rec_window_credit = tvb_get_ntohl(chunk_tvb, SACK_CHUNK_ADV_REC_WINDOW_CREDIT_OFFSET);
+  number_of_gap_blocks  = tvb_get_ntohs(chunk_tvb, SACK_CHUNK_NUMBER_OF_GAP_BLOCKS_OFFSET);
+  number_of_dup_tsns    = tvb_get_ntohs(chunk_tvb, SACK_CHUNK_NUMBER_OF_DUP_TSNS_OFFSET);
+  
+  proto_tree_add_uint(chunk_tree, hf_sctp_sack_chunk_cumulative_tsn_ack, 
+		      chunk_tvb,
+		      SACK_CHUNK_CUMULATIVE_TSN_ACK_OFFSET, SACK_CHUNK_CUMULATIVE_TSN_ACK_LENGTH,
+		      cumulative_tsn_ack);
+  proto_tree_add_uint(chunk_tree, hf_sctp_sack_chunk_adv_rec_window_credit, 
+		      chunk_tvb,
+		      SACK_CHUNK_ADV_REC_WINDOW_CREDIT_OFFSET, SACK_CHUNK_ADV_REC_WINDOW_CREDIT_LENGTH,
+		      adv_rec_window_credit);
+  proto_tree_add_uint(chunk_tree, hf_sctp_sack_chunk_number_of_gap_blocks, 
+		      chunk_tvb,
+		      SACK_CHUNK_NUMBER_OF_GAP_BLOCKS_OFFSET, SACK_CHUNK_NUMBER_OF_GAP_BLOCKS_LENGTH,
+		      number_of_gap_blocks);
+  proto_tree_add_uint(chunk_tree, hf_sctp_sack_chunk_number_of_dup_tsns, 
+		      chunk_tvb,
+		      SACK_CHUNK_NUMBER_OF_DUP_TSNS_OFFSET, SACK_CHUNK_NUMBER_OF_DUP_TSNS_LENGTH,
+		      number_of_dup_tsns);
+  
+  /* handle the gap acknowledgement blocks */
+  gap_block_offset = SACK_CHUNK_GAP_BLOCK_OFFSET;
+  for(gap_block_number = 1; gap_block_number <= number_of_gap_blocks; gap_block_number++) {
+    start = tvb_get_ntohs(chunk_tvb, gap_block_offset);
+    end   = tvb_get_ntohs(chunk_tvb, gap_block_offset + SACK_CHUNK_GAP_BLOCK_START_LENGTH);
+    block_item = proto_tree_add_text(chunk_tree, chunk_tvb,
+				     gap_block_offset, SACK_CHUNK_GAP_BLOCK_LENGTH,
+				     "Gap Acknowledgement for %u TSN%s",
+				     1 + end - start, plurality(1 + end - start, "", "s"));
+    block_tree = proto_item_add_subtree(block_item, ett_sctp_sack_chunk_gap_block);
+    proto_tree_add_uint(block_tree, hf_sctp_sack_chunk_gap_block_start, 
+			chunk_tvb,
+			gap_block_offset, SACK_CHUNK_GAP_BLOCK_START_LENGTH,
+			start);
+    proto_tree_add_uint(block_tree, hf_sctp_sack_chunk_gap_block_end, 
+			chunk_tvb,
+			gap_block_offset + SACK_CHUNK_GAP_BLOCK_START_LENGTH,
+			SACK_CHUNK_GAP_BLOCK_END_LENGTH,
+			end);
+    gap_block_offset += SACK_CHUNK_GAP_BLOCK_LENGTH;
+  };
+  
+  /* handle the duplicate TSNs */
+  dup_tsn_offset = SACK_CHUNK_GAP_BLOCK_OFFSET + number_of_gap_blocks * SACK_CHUNK_GAP_BLOCK_LENGTH;
+  for(dup_tsn_number = 1; dup_tsn_number <= number_of_dup_tsns; dup_tsn_number++) {
+    dup_tsn = tvb_get_ntohl(chunk_tvb, dup_tsn_offset);
+    proto_tree_add_uint(chunk_tree, hf_sctp_sack_chunk_duplicate_tsn, 
+			chunk_tvb,
+			dup_tsn, SACK_CHUNK_DUP_TSN_LENGTH,
+			dup_tsn);
+    dup_tsn_offset += SACK_CHUNK_DUP_TSN_LENGTH;
+  };
+
+  proto_item_set_text(chunk_item, 
+		      "SACK chunk acknowledging TSN %u and reporting %u gap%s and %u duplicate TSN%s",
+		      cumulative_tsn_ack,
+		      number_of_gap_blocks, plurality(number_of_gap_blocks, "", "s"),
+		      number_of_dup_tsns, plurality(number_of_dup_tsns, "", "s"));
+} 
+
+void
+dissect_heartbeat_chunk(tvbuff_t *chunk_tvb, 
+			proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{
+  tvbuff_t   *parameter_tvb;
+  guint chunk_length, info_length, padding_length, total_length;
+
+  chunk_length   = tvb_get_ntohs(chunk_tvb,  CHUNK_LENGTH_OFFSET);
+  info_length    = chunk_length - CHUNK_HEADER_LENGTH;
+  padding_length = nr_of_padding_bytes(info_length);
+  total_length   = info_length + padding_length;
+  parameter_tvb  = tvb_new_subset(chunk_tvb, HEARTBEAT_CHUNK_INFO_OFFSET, total_length, total_length);
+    
+  dissect_parameter(parameter_tvb, chunk_tree);
+
+  proto_item_set_text(chunk_item, "HEARTBEAT chunk");
+}
+ 
+void
+dissect_heartbeat_ack_chunk(tvbuff_t *chunk_tvb, 
+			    proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{  
+  tvbuff_t   *parameter_tvb;
+  guint chunk_length, info_length, padding_length, total_length;
+
+  chunk_length   = tvb_get_ntohs(chunk_tvb,  CHUNK_LENGTH_OFFSET);
+  info_length    = chunk_length - CHUNK_HEADER_LENGTH;
+  padding_length = nr_of_padding_bytes(info_length);
+  total_length   = info_length + padding_length;
+
+  parameter_tvb  = tvb_new_subset(chunk_tvb, HEARTBEAT_CHUNK_INFO_OFFSET, total_length, total_length);
+    
+  dissect_parameter(parameter_tvb, chunk_tree);
+
+  proto_item_set_text(chunk_item, "HEARTBEAT ACK chunk");
+} 
+
+void
+dissect_abort_chunk(tvbuff_t *chunk_tvb, 
+		    proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{
+  guint offset, number_of_causes;
+  guint16 length, padding_length, total_length;
+  tvbuff_t *cause_tvb;
+
+  number_of_causes = 0;
+  offset = ABORT_CHUNK_FIRST_ERROR_CAUSE_OFFSET;
+  while(tvb_length_remaining(chunk_tvb, offset)) {
+    length         = tvb_get_ntohs(chunk_tvb, offset + CAUSE_LENGTH_OFFSET);
+    padding_length = nr_of_padding_bytes(length);
+    total_length   = length + padding_length;
+    /* create a tvb for the chunk including the padding bytes */
+    cause_tvb      = tvb_new_subset(chunk_tvb, offset, total_length, total_length);
+    dissect_error_cause(cause_tvb, chunk_tree); 
+    /* get rid of the handled parameter */
+    offset += total_length;
+    number_of_causes++;
+  };
+
+  proto_item_set_text(chunk_item, "Abort chunk with %u cause%s",
+		      number_of_causes, plurality(number_of_causes, "", "s"));
+} 
+
+void
+dissect_shutdown_chunk(tvbuff_t *chunk_tvb, 
+		       proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint32 cumulative_tsn_ack;
+
+  cumulative_tsn_ack = tvb_get_ntohl(chunk_tvb, SHUTDOWN_CHUNK_CUMULATIVE_TSN_ACK_OFFSET);
+  proto_tree_add_uint(chunk_tree, hf_sctp_shutdown_chunk_cumulative_tsn_ack, 
+		      chunk_tvb,
+		      SHUTDOWN_CHUNK_CUMULATIVE_TSN_ACK_OFFSET,
+		      SHUTDOWN_CHUNK_CUMULATIVE_TSN_ACK_LENGTH,
+		      cumulative_tsn_ack);
+
+  proto_item_set_text(chunk_item, "SHUTDOWN chunk acknowledging up to TSN %u",
+		      cumulative_tsn_ack);
+} 
+
+void
+dissect_shutdown_ack_chunk(tvbuff_t *chunk_tvb, 
+			   proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  proto_item_set_text(chunk_item, "SHUTDOWN ACK chunk");
+} 
+
+void
+dissect_error_chunk(tvbuff_t *chunk_tvb, 
+		    proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint offset, number_of_causes;
+  guint16 length, padding_length, total_length;
+  tvbuff_t *cause_tvb;
+  
+  number_of_causes = 0;
+  offset = ERROR_CHUNK_FIRST_ERROR_CAUSE_OFFSET;
+  do {
+    length         = tvb_get_ntohs(chunk_tvb, offset + CAUSE_LENGTH_OFFSET);
+    padding_length = nr_of_padding_bytes(length);
+    total_length   = length + padding_length;
+    /* create a tvb for the chunk including the padding bytes */
+    cause_tvb      = tvb_new_subset(chunk_tvb, offset, total_length, total_length);
+    dissect_error_cause(cause_tvb, chunk_tree); 
+    /* get rid of the handled parameter */
+    offset += total_length;
+    number_of_causes++;
+  } while(tvb_length_remaining(chunk_tvb, offset));
+
+  proto_item_set_text(chunk_item, "Error chunk with %u cause%s",
+		      number_of_causes, plurality(number_of_causes, "", "s"));
+} 
+
+void
+dissect_cookie_echo_chunk(tvbuff_t *chunk_tvb, 
+			  proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint length, cookie_length, padding_length;
+
+  length         = tvb_get_ntohs(chunk_tvb, CHUNK_LENGTH_OFFSET);
+  padding_length = nr_of_padding_bytes(length);
+  cookie_length  = length - CHUNK_HEADER_LENGTH;
+  
+  proto_tree_add_text(chunk_tree, chunk_tvb, COOKIE_ECHO_CHUNK_COOKIE_OFFSET, cookie_length,
+		      "Cookie (%u byte%s)",
+		      cookie_length, plurality(cookie_length, "", "s"));
+  proto_item_set_text(chunk_item, "COOKIE ECHO chunk containing a cookie of %u byte%s",
+		      cookie_length, plurality(cookie_length, "", "s"));
+
+  if (padding_length > 0)
+    proto_tree_add_text(chunk_tree, chunk_tvb, CHUNK_HEADER_OFFSET + length, padding_length,
+			"Padding: %u byte%s",
+			padding_length, plurality(padding_length, "", "s"));
+} 
+
+void
+dissect_cookie_ack_chunk(tvbuff_t *chunk_tvb, 
+			 proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  proto_item_set_text(chunk_item, "COOKIE ACK chunk");
+} 
+
+void
+dissect_ecne_chunk(tvbuff_t *chunk_tvb, 
+		   proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint32 lowest_tsn;
+
+  lowest_tsn = tvb_get_ntohl(chunk_tvb, ECNE_CHUNK_LOWEST_TSN_OFFSET);
+  proto_tree_add_uint(chunk_tree, hf_sctp_ecne_chunk_lowest_tsn, 
+		      chunk_tvb,
+		      ECNE_CHUNK_LOWEST_TSN_OFFSET, ECNE_CHUNK_LOWEST_TSN_LENGTH,
+		      lowest_tsn);
+
+  proto_item_set_text(chunk_item, "ECNE chunk");
+} 
+
+void
+dissect_cwr_chunk(tvbuff_t *chunk_tvb, 
+		  proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint32 lowest_tsn;
+
+  lowest_tsn = tvb_get_ntohl(chunk_tvb, CWR_CHUNK_LOWEST_TSN_OFFSET);
+  proto_tree_add_uint(chunk_tree, hf_sctp_cwr_chunk_lowest_tsn, 
+		      chunk_tvb,
+		      CWR_CHUNK_LOWEST_TSN_OFFSET, CWR_CHUNK_LOWEST_TSN_LENGTH,
+		      lowest_tsn);
+
+  proto_item_set_text(chunk_item, "CWR chunk");
+} 
+
+void
+dissect_shutdown_complete_chunk(tvbuff_t *chunk_tvb, 
+				proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint8  flags;
+  guint16 length;
+  proto_tree *flag_tree;
+
+  flags             = tvb_get_guint8(chunk_tvb, CHUNK_FLAGS_OFFSET);
+  length            = tvb_get_ntohs(chunk_tvb, CHUNK_LENGTH_OFFSET);
+
+  flag_tree = proto_item_add_subtree(flags_item, ett_sctp_data_chunk_flags);
+  proto_tree_add_boolean(flag_tree, hf_sctp_shutdown_complete_chunk_t_bit, chunk_tvb,
+			 CHUNK_FLAGS_OFFSET, CHUNK_FLAGS_LENGTH, flags);
+
+  proto_item_set_text(chunk_item, "SHUTDOWN COMPLETE chunk");
+} 
+
+void
+dissect_unknown_chunk(tvbuff_t *chunk_tvb, 
+		      proto_tree *chunk_tree, proto_item *chunk_item, proto_item *flags_item)
+{ 
+  guint length, chunk_value_length, padding_length;
+  guint8 type;
+
+  length         = tvb_get_ntohs(chunk_tvb, CHUNK_LENGTH_OFFSET);
+  padding_length = nr_of_padding_bytes(length);
+  type           = tvb_get_guint8(chunk_tvb, CHUNK_TYPE_OFFSET);
+ 
+  chunk_value_length = length - CHUNK_HEADER_LENGTH;
+  
+  proto_tree_add_text(chunk_tree, chunk_tvb, CHUNK_VALUE_OFFSET, chunk_value_length,
+		      "Chunk value (%u byte%s)",
+		      chunk_value_length, plurality(chunk_value_length, "", "s"));
+  
+  if (padding_length > 0)
+    proto_tree_add_text(chunk_tree, chunk_tvb, CHUNK_HEADER_OFFSET + length, padding_length,
+			"Padding: %u byte%s",
+			padding_length, plurality(padding_length, "", "s"));
+   
+  proto_item_set_text(chunk_item, "Chunk of type %u and %u byte%s value",
+		      type, chunk_value_length, plurality(chunk_value_length, "", "s"));
+
+ 
+} 
+
+
+void
+dissect_sctp_chunk(tvbuff_t *chunk_tvb, proto_tree *sctp_tree)
+{  
+  guint8 type, flags;
+  guint16 length;
+  proto_item *flags_item;
+  proto_item *chunk_item;
+  proto_tree *chunk_tree;
+
+  /* first extract the chunk header */
+  type   = tvb_get_guint8(chunk_tvb, CHUNK_TYPE_OFFSET);
+  flags  = tvb_get_guint8(chunk_tvb, CHUNK_FLAGS_OFFSET);
+  length = tvb_get_ntohs(chunk_tvb, CHUNK_LENGTH_OFFSET);
+
+  /* create proto_tree stuff */
+  chunk_item   = proto_tree_add_text(sctp_tree, chunk_tvb,
+				     CHUNK_HEADER_OFFSET, tvb_length(chunk_tvb), "Incomplete chunk");
+  chunk_tree   = proto_item_add_subtree(chunk_item, ett_sctp_chunk);
+  
+  /* then insert the chunk header components into the protocol tree */
+  proto_tree_add_uint_format(chunk_tree, hf_sctp_chunk_type, 
+			     chunk_tvb, CHUNK_TYPE_OFFSET, CHUNK_TYPE_LENGTH,
+			     type, "Identifier: %u (%s)",
+			     type, val_to_str(type, sctp_chunk_type_values, "unknown"));
+  flags_item = proto_tree_add_uint(chunk_tree, hf_sctp_chunk_flags, 
+		      chunk_tvb, CHUNK_FLAGS_OFFSET, CHUNK_FLAGS_LENGTH,
+		      flags);
+  proto_tree_add_uint(chunk_tree, hf_sctp_chunk_length, 
+		      chunk_tvb, CHUNK_LENGTH_OFFSET, CHUNK_LENGTH_LENGTH,
+		      length);
+  
+  /* now dissect the chunk value */
+  switch(type) {
+  case SCTP_DATA_CHUNK_ID:
+    dissect_data_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_INIT_CHUNK_ID:
+    dissect_init_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_INIT_ACK_CHUNK_ID:
+    dissect_init_ack_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_SACK_CHUNK_ID:
+    dissect_sack_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break; 
+  case SCTP_HEARTBEAT_CHUNK_ID:
+    dissect_heartbeat_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_HEARTBEAT_ACK_CHUNK_ID:
+    dissect_heartbeat_ack_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_ABORT_CHUNK_ID:
+    dissect_abort_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_SHUTDOWN_CHUNK_ID:
+    dissect_shutdown_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_SHUTDOWN_ACK_CHUNK_ID:
+    dissect_shutdown_ack_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_ERROR_CHUNK_ID:
+    dissect_error_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_COOKIE_ECHO_CHUNK_ID:
+    dissect_cookie_echo_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_COOKIE_ACK_CHUNK_ID:
+    dissect_cookie_ack_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_ECNE_CHUNK_ID:
+    dissect_ecne_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_CWR_CHUNK_ID:
+    dissect_cwr_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  case SCTP_SHUTDOWN_COMPLETE_CHUNK_ID:
+    dissect_shutdown_complete_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  default:
+    dissect_unknown_chunk(chunk_tvb, chunk_tree, chunk_item, flags_item);
+    break;
+  }  
+}
+
+void
+dissect_sctp_chunks(tvbuff_t *tvb, proto_tree *sctp_tree)
+{ 
+  tvbuff_t *chunk_tvb;
+  guint16 length, padding_length, total_length;
+  gint offset;
+  
+  /* the common header of the datagram is already handled */
+  offset = COMMON_HEADER_LENGTH;
+
+  while(tvb_length_remaining(tvb, offset) > 0) {
+    /* extract the chunk length and compute number of padding bytes */
+    length         = tvb_get_ntohs(tvb, offset + CHUNK_LENGTH_OFFSET);
+    padding_length = nr_of_padding_bytes(length);
+    total_length   = length + padding_length;
+    /* create a tvb for the chunk including the padding bytes */
+    chunk_tvb    = tvb_new_subset(tvb, offset, total_length, total_length);
+    /* call dissect_sctp_chunk for a actual work */
+    dissect_sctp_chunk(chunk_tvb, sctp_tree);
+    /* get rid of the dissected chunk */
+    offset += total_length;
+  }
+}
+
+
+
+/* dissect_sctp handles the common header of a SCTP datagram.
+ * For the handling of the chunks dissect_sctp_chunks is called.
+ */
+
+#if 0
+static void
+dissect_sctp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+#else
+static void
+dissect_sctp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
+{
+        tvbuff_t *tvb = tvb_create_from_top(offset);
+        packet_info *pinfo = &pi;
+#endif
+
+  guint16 source_port, destination_port;
+  guint32 verification_tag, checksum;
+  proto_item *ti;
+  proto_tree *sctp_tree;
+
+  pinfo->current_proto = "SCTP";
+
+  /* Extract the common header */
+  source_port      = tvb_get_ntohs(tvb, SOURCE_PORT_OFFSET);
+  destination_port = tvb_get_ntohs(tvb, DESTINATION_PORT_OFFSET);
+  verification_tag = tvb_get_ntohl(tvb, VERIFICATION_TAG_OFFSET);
+  checksum         = tvb_get_ntohl(tvb, CHECKSUM_OFFSET);
+
+  /* make entry in the Protocol column on summary display */
+  if (check_col(fd, COL_PROTOCOL)) 
+    col_add_str(fd, COL_PROTOCOL, "SCTP");
+
+  /* Make entries in Info column on summary display */
+  if (check_col(fd, COL_INFO)) 
+    col_add_fstr(fd, COL_INFO, "%u > %u: tag 0x%x",
+		 source_port, destination_port, verification_tag);
+  
+  /* In the interest of speed, if "tree" is NULL, don't do any work not
+     necessary to generate protocol tree items. */
+  if (tree) {
+    /* create the sctp protocol tree */
+    ti = proto_tree_add_protocol_format(tree, proto_sctp, tvb, 0, tvb_length(tvb), 
+					"Stream Control Transmission Protocol");
+    sctp_tree = proto_item_add_subtree(ti, ett_sctp);
+
+    /* add the components of the common header to the protocol tree */
+    proto_tree_add_uint(sctp_tree, hf_sctp_source_port, 
+			tvb, SOURCE_PORT_OFFSET, SOURCE_PORT_LENGTH,
+			source_port);
+    proto_tree_add_uint(sctp_tree, hf_sctp_destination_port,
+			tvb, DESTINATION_PORT_OFFSET, DESTINATION_PORT_LENGTH,
+			destination_port);
+    proto_tree_add_uint(sctp_tree, hf_sctp_verification_tag,
+			tvb, VERIFICATION_TAG_OFFSET, VERIFICATION_TAG_LENGTH,
+			verification_tag);
+    proto_tree_add_uint_format(sctp_tree, hf_sctp_checksum,
+			       tvb, CHECKSUM_OFFSET, CHECKSUM_LENGTH, checksum,
+			       "Adler-32 checksum: 0x%08x (%s)",
+			       checksum, sctp_checksum_state(tvb, checksum));
+    
+    /* add all chunks of the sctp datagram to the protocol tree */
+    dissect_sctp_chunks(tvb, sctp_tree);
+  };
+}
+
+/* Register the protocol with Ethereal */
+void
+proto_register_sctp(void)
+{                 
+
+  /* Setup list of header fields */
+  static hf_register_info hf[] = {
+    { &hf_sctp_source_port,
+      { "Source port", "sctp.srcport",
+	FT_UINT16, BASE_DEC, NULL, 0x0,          
+	""}
+    },
+    { &hf_sctp_destination_port,
+      { "Destination port", "sctp.dstport",
+	FT_UINT16, BASE_DEC, NULL, 0x0,          
+	""}
+    }, 
+    { &hf_sctp_verification_tag,
+      { "Verification tag", "sctp.verfication_tag",
+	FT_UINT32, BASE_HEX, NULL, 0x0,          
+	""}
+    },
+    { &hf_sctp_checksum,
+      { "Adler-32 checksum", "sctp.checksum",
+	FT_UINT32, BASE_HEX, NULL, 0x0,          
+	""}
+    },
+    { &hf_sctp_chunk_type,
+      { "Identifier", "sctp.chunk_type",
+	FT_UINT8, BASE_DEC, NULL, 0x0,          
+	""}
+    },
+    { &hf_sctp_chunk_flags,
+      { "Flags", "sctp.chunk_flags",
+	FT_UINT8, BASE_BIN, NULL, 0x0,          
+	""}
+    },
+    { &hf_sctp_chunk_length,
+      { "Length", "sctp.chunk_length",
+	FT_UINT16, BASE_DEC, NULL, 0x0,          
+	""}
+    },
+    { &hf_sctp_init_chunk_initiate_tag,
+      { "Initiate tag", "sctp.init.chunk.initiate.tag",
+	FT_UINT32, BASE_HEX, NULL, 0x0,          
+	""}
+    },
+    { &hf_sctp_init_chunk_adv_rec_window_credit,
+      { "Advertised reciever window credit (a_rwnd)", "sctp.init.chunk.credit",
+	FT_UINT32, BASE_DEC, NULL, 0x0,          
+	""}
+    },
+    { &hf_sctp_init_chunk_number_of_outbound_streams,
+      { "Number of outbound streams", "sctp.init.chunk.nr.out.streams",
+	FT_UINT16, BASE_DEC, NULL, 0x0,          
+	""}
+    },
+    { &hf_sctp_init_chunk_number_of_inbound_streams,
+      { "Number of inbound streams", "sctp.init.chunk.nr.in.streams",
+	FT_UINT16, BASE_DEC, NULL, 0x0,          
+	""}
+    },
+    {&hf_sctp_init_chunk_initial_tsn,
+      { "Initial TSN", "sctp.init.chunk.initial.tsn",
+	FT_UINT32, BASE_DEC, NULL, 0x0,          
+	""}
+    }, 
+    {&hf_sctp_cumulative_tsn_ack,
+     { "Cumulative TSN Ack", "sctp.cumulative.tsn.ack",
+	FT_UINT32, BASE_DEC, NULL, 0x0,          
+	""}
+    },
+    {&hf_sctp_data_chunk_tsn,
+     { "TSN", "sctp.tsn",
+       FT_UINT32, BASE_DEC, NULL, 0x0,          
+	""}
+    },
+    {&hf_sctp_data_chunk_stream_id,
+     { "Stream Identifier", "sctp.stream_id",
+	FT_UINT16, BASE_HEX, NULL, 0x0,          
+	""}
+    },
+    {&hf_sctp_data_chunk_stream_seq_number,
+     { "Stream sequence number", "sctp.stream_seq_number",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_data_chunk_payload_proto_id,
+     { "Payload Protocol identifier", "sctp.payload_proto_id",
+	FT_UINT32, BASE_HEX, NULL, 0x0,          
+	""}
+    },
+    {&hf_sctp_data_chunk_e_bit,
+     { "E-Bit", "sctp.data.e_bit",
+       FT_BOOLEAN, 8, TFS(&sctp_data_chunk_e_bit_value), SCTP_DATA_CHUNK_E_BIT,          
+       ""}
+    },
+    {&hf_sctp_data_chunk_b_bit,
+     { "B-Bit", "sctp.data.b_bit",
+       FT_BOOLEAN, 8, TFS(&sctp_data_chunk_b_bit_value), SCTP_DATA_CHUNK_B_BIT,          
+       ""}
+    },
+    {&hf_sctp_data_chunk_u_bit,
+     { "U-Bit", "sctp.data.u.bit",
+       FT_BOOLEAN, 8, TFS(&sctp_data_chunk_u_bit_value), SCTP_DATA_CHUNK_U_BIT,          
+       ""}
+    },
+    {&hf_sctp_sack_chunk_cumulative_tsn_ack,
+     { "Cumulative TSN ACK", "sctp.sack.cumulative_tsn_ack",
+       FT_UINT32, BASE_DEC, NULL, 0x0,          
+       ""}
+    }, 
+    {&hf_sctp_sack_chunk_adv_rec_window_credit,
+     { "Advertised receiver window credit (a_rwnd)", "sctp.sack.a_rwnd",
+       FT_UINT32, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_sack_chunk_number_of_gap_blocks,
+     { "Number of gap acknowldgement blocks ", "sctp.sack.number_of_gap_blocks",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    }, 
+    {&hf_sctp_sack_chunk_number_of_dup_tsns,
+     { "Number of duplicated TSNs", "sctp.sack.number_of_duplicated_tsns",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_sack_chunk_gap_block_start,
+     { "Start", "sctp.sack.gap_block_start",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_sack_chunk_gap_block_end,
+     { "End", "sctp.sack.gap_block_end",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_sack_chunk_duplicate_tsn,
+     { "Duplicate TSN", "sctp.sack.duplicate.tsn",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    },  
+    {&hf_sctp_shutdown_chunk_cumulative_tsn_ack,
+     { "Cumulative TSN Ack", "sctp.shutdown.cumulative_tsn_ack",
+	FT_UINT32, BASE_DEC, NULL, 0x0,          
+	""}
+    },
+    {&hf_sctp_ecne_chunk_lowest_tsn,
+     { "Lowest TSN", "sctp.ecne.lowest_tsn",
+       FT_UINT32, BASE_DEC, NULL, 0x0,          
+       ""}
+    }, 
+    {&hf_sctp_cwr_chunk_lowest_tsn,
+     { "Lowest TSN", "sctp.cwr.lowest_tsn",
+       FT_UINT32, BASE_DEC, NULL, 0x0,          
+       ""}
+    }, 
+    {&hf_sctp_shutdown_complete_chunk_t_bit,
+     { "E-Bit", "sctp.shutdown_complete.t_bit",
+       FT_BOOLEAN, 8, TFS(&sctp_shutdown_complete_chunk_t_bit_value), SCTP_SHUTDOWN_COMPLETE_CHUNK_T_BIT,
+       ""}
+    },
+    {&hf_sctp_chunk_parameter_type,
+     { "Parameter type", "sctp.parameter.type",
+       FT_UINT16, BASE_HEX, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_chunk_parameter_length,
+     { "Parameter length", "sctp.parameter.length",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_parameter_ipv4_address,
+     { "IP Version 4 address", "sctp.parameter.ipv4_address",
+       FT_IPv4, BASE_NONE, NULL, 0x0,
+       ""}
+    },
+    {&hf_sctp_parameter_ipv6_address,
+     { "IP Version 6 address", "sctp.parameter.ipv6_address",
+       FT_IPv6, BASE_NONE, NULL, 0x0,
+       ""}
+    },
+    {&hf_sctp_parameter_cookie_preservative_increment,
+     { "Suggested Cookie life-span increment (msec)", "sctp.parameter.cookie_preservative_incr",
+       FT_UINT32, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_parameter_hostname_hostname,
+     { "Hostname", "sctp.parameter.hostname.hostname",
+       FT_STRING, BASE_NONE, NULL, 0x0,          
+       ""}
+    }, 
+    {&hf_sctp_supported_address_types_parameter,
+     { "Supported address type", "sctp.parameter.supported_addres_type",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    }, 
+    {&hf_sctp_cause_code,
+     { "Cause code", "sctp.cause.code",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_cause_length,
+     { "Cause length", "sctp.cause.length",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    }, 
+    {&hf_sctp_cause_stream_identifier,
+     { "Stream identifier", "sctp.cause.stream_identifier",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_cause_number_of_missing_parameters,
+     { "Number of missing parameters", "sctp.cause.nr_of_missing_parameters",
+       FT_UINT32, BASE_DEC, NULL, 0x0,          
+       ""}
+    }, 
+    {&hf_sctp_cause_missing_parameter_type,
+     { "Missing parameters type", "sctp.cause.missing_parameter_type",
+       FT_UINT16, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_cause_measure_of_staleness,
+     { "Measure of staleness in usec", "sctp.cause.measure_of_staleness",
+       FT_UINT32, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+    {&hf_sctp_cause_tsn,
+     { "TSN", "sctp.cause.tsn",
+       FT_UINT32, BASE_DEC, NULL, 0x0,          
+       ""}
+    },
+  };
+  
+  /* Setup protocol subtree array */
+  static gint *ett[] = {
+    &ett_sctp,
+    &ett_sctp_chunk,
+    &ett_sctp_chunk_parameter,
+    &ett_sctp_chunk_cause,
+    &ett_sctp_data_chunk_flags,
+    &ett_sctp_sack_chunk_gap_block,
+    &ett_sctp_supported_address_types_parameter,
+    &ett_sctp_unrecognized_parameter_parameter
+  };
+  
+  /* Register the protocol name and description */
+  proto_sctp = proto_register_protocol("Stream Control Transmission Protcol",
+				       "sctp");
+  
+  /* Required function calls to register the header fields and subtrees used */
+  proto_register_field_array(proto_sctp, hf, array_length(hf));
+  proto_register_subtree_array(ett, array_length(ett));
+};
+
+void
+proto_reg_handoff_sctp(void)
+{
+	dissector_add("ip.proto", IP_PROTO_SCTP, dissect_sctp);
+}
+
+
+
+
+
+
+