Revert "SCTP: Add I_DATA support"

This reverts commit 4e9361dc88eefef27d031e29e2f8ca9891cc03eb.

Change-Id: Ia7aee9ffbe5bc5d3ae88e957c234cbee7b65f457
Reviewed-on: https://code.wireshark.org/review/10723
Reviewed-by: Michael Tüxen <tuexen@wireshark.org>

8 files changed, 79 insertions, 228 deletions

diff --git a/epan/dissectors/packet-sctp.c b/epan/dissectors/packet-sctp.c
index cc1b403e9e..54813dd13b 100644
--- a/epan/dissectors/packet-sctp.c
+++ b/epan/dissectors/packet-sctp.c
@@ -117,9 +117,6 @@ static int hf_data_chunk_tsn = -1;
 static int hf_data_chunk_stream_id = -1;
 static int hf_data_chunk_stream_seq_number = -1;
 static int hf_data_chunk_payload_proto_id = -1;
-static int hf_idata_chunk_reserved = -1;
-static int hf_idata_chunk_mid = -1;
-static int hf_idata_chunk_fsn = -1;
 
 static int hf_data_chunk_e_bit = -1;
 static int hf_data_chunk_b_bit = -1;
@@ -325,7 +322,6 @@ static dissector_handle_t data_handle;
 #define SCTP_SHUTDOWN_COMPLETE_CHUNK_ID 14
 #define SCTP_AUTH_CHUNK_ID              15
 #define SCTP_NR_SACK_CHUNK_ID           16
-#define SCTP_I_DATA_CHUNK_ID          0x40
 #define SCTP_ASCONF_ACK_CHUNK_ID      0x80
 #define SCTP_PKTDROP_CHUNK_ID         0x81
 #define SCTP_RE_CONFIG_CHUNK_ID       0x82
@@ -352,7 +348,6 @@ static const value_string chunk_type_values[] = {
   { SCTP_SHUTDOWN_COMPLETE_CHUNK_ID, "SHUTDOWN_COMPLETE" },
   { SCTP_AUTH_CHUNK_ID,              "AUTH" },
   { SCTP_NR_SACK_CHUNK_ID,           "NR-SACK" },
-  { SCTP_I_DATA_CHUNK_ID,            "I-DATA" },
   { SCTP_ASCONF_ACK_CHUNK_ID,        "ASCONF_ACK" },
   { SCTP_PKTDROP_CHUNK_ID,           "PKTDROP" },
   { SCTP_RE_CONFIG_CHUNK_ID,         "RE_CONFIG" },
@@ -518,8 +513,6 @@ typedef struct _infodata_t {
 
 static wmem_list_t *assoc_info_list = NULL;
 static guint num_assocs = 0;
-static guint32 frag_ppid = 0;  /* Save the PPID for the fragmented idata packets, as they
-are only present in the first fragment */
 
 UAT_CSTRING_CB_DEF(type_fields, type_name, type_field_t)
 UAT_VS_DEF(type_fields, type_enable, type_field_t, guint, 0, "Show")
@@ -944,7 +937,7 @@ static void dissect_error_cause(tvbuff_t *, packet_info *, proto_tree *);
 
 static void dissect_error_causes(tvbuff_t *, packet_info *, proto_tree *);
 
-static gboolean dissect_data_chunk(tvbuff_t*, guint16, packet_info*, proto_tree*, proto_tree*, proto_item*, proto_item*, sctp_half_assoc_t*, gboolean);
+static gboolean dissect_data_chunk(tvbuff_t*, guint16, packet_info*, proto_tree*, proto_tree*, proto_item*, proto_item*, sctp_half_assoc_t*);
 
 static void dissect_sctp_packet(tvbuff_t *, packet_info *, proto_tree *, gboolean);
 
@@ -2544,41 +2537,21 @@ dissect_payload(tvbuff_t *payload_tvb, packet_info *pinfo, proto_tree *tree, gui
 #define DATA_CHUNK_STREAM_ID_LENGTH   2
 #define DATA_CHUNK_STREAM_SEQ_NUMBER_LENGTH 2
 #define DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH 4
-#define I_DATA_CHUNK_RESERVED_LENGTH 2
-#define I_DATA_CHUNK_MID_LENGTH 4
-#define I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH 4
-#define I_DATA_CHUNK_FSN_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_ID_LENGTH)
+                                             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 I_DATA_CHUNK_RESERVED_OFFSET  (DATA_CHUNK_STREAM_ID_OFFSET + \
-                                       DATA_CHUNK_STREAM_ID_LENGTH)
-#define I_DATA_CHUNK_MID_OFFSET       (I_DATA_CHUNK_RESERVED_OFFSET + \
-                                       I_DATA_CHUNK_RESERVED_LENGTH)
-#define I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET (I_DATA_CHUNK_MID_OFFSET + \
-                                                 I_DATA_CHUNK_MID_LENGTH)
-#define I_DATA_CHUNK_FSN_OFFSET       (I_DATA_CHUNK_MID_OFFSET + \
-                                       I_DATA_CHUNK_MID_LENGTH)
-#define I_DATA_CHUNK_PAYLOAD_OFFSET   (I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET + \
-                                       I_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 I_DATA_CHUNK_HEADER_LENGTH    (CHUNK_HEADER_LENGTH + \
-                                       DATA_CHUNK_TSN_LENGTH + \
-                                       DATA_CHUNK_STREAM_ID_LENGTH + \
-                                       I_DATA_CHUNK_RESERVED_LENGTH + \
-                                       I_DATA_CHUNK_MID_LENGTH +\
-                                       I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH)
 
 #define SCTP_DATA_CHUNK_E_BIT 0x01
 #define SCTP_DATA_CHUNK_B_BIT 0x02
@@ -2594,8 +2567,7 @@ typedef struct _frag_key {
   guint16 dport;
   guint32 verification_tag;
   guint16 stream_id;
-  guint32 stream_seq_num;
-  guint8 u_bit;
+  guint16 stream_seq_num;
 } frag_key;
 
 
@@ -2609,8 +2581,7 @@ frag_equal(gconstpointer k1, gconstpointer k2)
            (key1->dport == key2->dport) &&
            (key1->verification_tag == key2->verification_tag) &&
            (key1->stream_id == key2->stream_id) &&
-           (key1->stream_seq_num == key2->stream_seq_num) &&
-           (key1->u_bit == key2->u_bit)
+           (key1->stream_seq_num == key2->stream_seq_num)
            ? TRUE : FALSE);
 }
 
@@ -2621,7 +2592,7 @@ frag_hash(gconstpointer k)
   const frag_key *key = (const frag_key *) k;
 
   return key->sport ^ key->dport ^ key->verification_tag ^
-         key->stream_id ^ key->stream_seq_num ^ key->u_bit;
+         key->stream_id ^ key->stream_seq_num;
 }
 
 
@@ -2676,7 +2647,7 @@ sctp_cleanup(void)
 
 
 static sctp_frag_msg*
-find_message(guint16 stream_id, guint32 stream_seq_num, guint8 u_bit)
+find_message(guint16 stream_id, guint16 stream_seq_num)
 {
   frag_key key;
 
@@ -2685,19 +2656,18 @@ find_message(guint16 stream_id, guint32 stream_seq_num, guint8 u_bit)
   key.verification_tag = sctp_info.verification_tag;
   key.stream_id = stream_id;
   key.stream_seq_num = stream_seq_num;
-  key.u_bit = u_bit;
 
   return (sctp_frag_msg *)g_hash_table_lookup(frag_table, &key);
 }
 
 
 static sctp_fragment*
-find_fragment(guint32 tsn, guint16 stream_id, guint32 stream_seq_num, guint8 u_bit)
+find_fragment(guint32 tsn, guint16 stream_id, guint16 stream_seq_num)
 {
   sctp_frag_msg *msg;
   sctp_fragment *next_fragment;
 
-  msg = find_message(stream_id, stream_seq_num, u_bit);
+  msg = find_message(stream_id, stream_seq_num);
 
   if (msg) {
     next_fragment = msg->fragments;
@@ -2714,7 +2684,7 @@ find_fragment(guint32 tsn, guint16 stream_id, guint32 stream_seq_num, guint8 u_b
 
 static sctp_fragment *
 add_fragment(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 tsn,
-             guint16 stream_id, guint32 stream_seq_num, guint8 b_bit, guint8 e_bit, guint8 u_bit)
+             guint16 stream_id, guint16 stream_seq_num, guint8 b_bit, guint8 e_bit)
 {
   sctp_frag_msg *msg;
   sctp_fragment *fragment, *last_fragment;
@@ -2726,7 +2696,7 @@ add_fragment(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 tsn,
     return NULL;
 
   /* lookup message. if not found, create it */
-  msg = find_message(stream_id, stream_seq_num, u_bit);
+  msg = find_message(stream_id, stream_seq_num);
 
   if (!msg) {
     msg = (sctp_frag_msg *)g_malloc (sizeof (sctp_frag_msg));
@@ -2742,13 +2712,12 @@ add_fragment(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 tsn,
     key->verification_tag = sctp_info.verification_tag;
     key->stream_id = stream_id;
     key->stream_seq_num = stream_seq_num;
-    key->u_bit = u_bit;
 
     g_hash_table_insert(frag_table, key, msg);
   }
 
   /* lookup segment. if not found, create it */
-  fragment = find_fragment(tsn, stream_id, stream_seq_num, u_bit);
+  fragment = find_fragment(tsn, stream_id, stream_seq_num);
 
   if (fragment) {
     /* this fragment is already known.
@@ -2861,7 +2830,7 @@ add_fragment(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 tsn,
 static tvbuff_t*
 fragment_reassembly(tvbuff_t *tvb, sctp_fragment *fragment,
                     packet_info *pinfo, proto_tree *tree, guint16 stream_id,
-                    guint32 stream_seq_num, guint8 u_bit)
+                    guint16 stream_seq_num)
 {
   sctp_frag_msg *msg;
   sctp_complete_msg *message, *last_message;
@@ -2872,7 +2841,7 @@ fragment_reassembly(tvbuff_t *tvb, sctp_fragment *fragment,
   proto_item *item;
   proto_tree *ptree;
 
-  msg = find_message(stream_id, stream_seq_num, u_bit);
+  msg = find_message(stream_id, stream_seq_num);
 
   if (!msg) {
     /* no message, we can't do anything */
@@ -2902,7 +2871,7 @@ fragment_reassembly(tvbuff_t *tvb, sctp_fragment *fragment,
                              message->len, message->end - message->begin + 1);
 
       if (message->begin > message->end) {
-        for (frag_i = find_fragment(message->begin, stream_id, stream_seq_num, u_bit);
+        for (frag_i = find_fragment(message->begin, stream_id, stream_seq_num);
              frag_i;
              frag_i = frag_i->next) {
 
@@ -2926,7 +2895,7 @@ fragment_reassembly(tvbuff_t *tvb, sctp_fragment *fragment,
           mark_frame_as_depended_upon(pinfo, frag_i->frame_num);
         }
       } else {
-        for (frag_i = find_fragment(message->begin, stream_id, stream_seq_num, u_bit);
+        for (frag_i = find_fragment(message->begin, stream_id, stream_seq_num);
              frag_i && frag_i->tsn <= message->end;
              frag_i = frag_i->next) {
 
@@ -3141,7 +3110,7 @@ fragment_reassembly(tvbuff_t *tvb, sctp_fragment *fragment,
                          message->len, message->end - message->begin + 1);
 
   if (message->begin > message->end) {
-    for (frag_i = find_fragment(message->begin, stream_id, stream_seq_num, u_bit);
+    for (frag_i = find_fragment(message->begin, stream_id, stream_seq_num);
          frag_i;
          frag_i = frag_i->next) {
 
@@ -3161,7 +3130,7 @@ fragment_reassembly(tvbuff_t *tvb, sctp_fragment *fragment,
       offset += frag_i->len;
     }
   } else {
-    for (frag_i = find_fragment(message->begin, stream_id, stream_seq_num, u_bit);
+    for (frag_i = find_fragment(message->begin, stream_id, stream_seq_num);
          frag_i && frag_i->tsn <= message->end;
          frag_i = frag_i->next) {
 
@@ -3200,7 +3169,7 @@ export_sctp_data_chunk(packet_info *pinfo, tvbuff_t *tvb, const gchar *proto_nam
 static gboolean
 dissect_fragmented_payload(tvbuff_t *payload_tvb, packet_info *pinfo, proto_tree *tree,
                            proto_tree *chunk_tree, guint32 tsn, guint32 ppi, guint16 stream_id,
-                           guint32 stream_seq_num, guint8 b_bit, guint8 e_bit, guint8 u_bit)
+                           guint16 stream_seq_num, guint8 b_bit, guint8 e_bit)
 {
   sctp_fragment *fragment;
   tvbuff_t *new_tvb = NULL;
@@ -3212,11 +3181,11 @@ dissect_fragmented_payload(tvbuff_t *payload_tvb, packet_info *pinfo, proto_tree
   if (tvb_reported_length(payload_tvb) > tvb_captured_length(payload_tvb))
     return TRUE;
 
-  /* add fragment to list of known fragments. returns NULL if segment is a duplicate */
-  fragment = add_fragment(payload_tvb, pinfo, chunk_tree, tsn, stream_id, stream_seq_num, b_bit, e_bit, u_bit);
+  /* add fragement to list of known fragments. returns NULL if segment is a duplicate */
+  fragment = add_fragment(payload_tvb, pinfo, chunk_tree, tsn, stream_id, stream_seq_num, b_bit, e_bit);
 
   if (fragment)
-    new_tvb = fragment_reassembly(payload_tvb, fragment, pinfo, chunk_tree, stream_id, stream_seq_num, u_bit);
+    new_tvb = fragment_reassembly(payload_tvb, fragment, pinfo, chunk_tree, stream_id, stream_seq_num);
 
   /* pass reassembled data to next dissector, if possible */
   if (new_tvb){
@@ -3270,33 +3239,25 @@ dissect_data_chunk(tvbuff_t *chunk_tvb,
                    proto_tree *chunk_tree,
                    proto_item *chunk_item,
                    proto_item *flags_item,
-                   sctp_half_assoc_t* ha,
-                   gboolean is_idata)
+                   sctp_half_assoc_t *ha)
 {
   guint number_of_ppid;
   guint32 payload_proto_id;
   tvbuff_t *payload_tvb;
   proto_tree *flags_tree;
   guint8 e_bit, b_bit, u_bit;
-  guint16 stream_id;
-  guint32 tsn, ppid, stream_seq_num = 0;
+  guint16 stream_id, stream_seq_num = 0;
+  guint32 tsn, ppid;
   proto_item *tsn_item = NULL;
   gboolean call_subdissector = FALSE;
   gboolean is_retransmission;
 
-  if (is_idata) {
-    if (chunk_length < I_DATA_CHUNK_HEADER_LENGTH) {
-      proto_item_append_text(chunk_item, ", bogus chunk length %u < %u)", chunk_length, I_DATA_CHUNK_HEADER_LENGTH);
-      return TRUE;
-    }
-    payload_proto_id  = tvb_get_ntohl(chunk_tvb, I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET);
-} else {
-    if (chunk_length < DATA_CHUNK_HEADER_LENGTH) {
-      proto_item_append_text(chunk_item, ", bogus chunk length %u < %u)", chunk_length, DATA_CHUNK_HEADER_LENGTH);
-      return TRUE;
-    }
-    payload_proto_id  = tvb_get_ntohl(chunk_tvb, DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET);
-}
+  if (chunk_length <= DATA_CHUNK_HEADER_LENGTH) {
+    proto_item_append_text(chunk_item, ", bogus chunk length %u < %u)", chunk_length, DATA_CHUNK_HEADER_LENGTH);
+    return TRUE;
+  }
+
+  payload_proto_id  = tvb_get_ntohl(chunk_tvb, DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET);
 
   /* insert the PPID in the pinfo structure if it is not already there and there is still room */
   for(number_of_ppid = 0; number_of_ppid < MAX_NUMBER_OF_PPIDS; number_of_ppid++) {
@@ -3310,13 +3271,12 @@ dissect_data_chunk(tvbuff_t *chunk_tvb,
   e_bit = tvb_get_guint8(chunk_tvb, CHUNK_FLAGS_OFFSET) & SCTP_DATA_CHUNK_E_BIT;
   b_bit = tvb_get_guint8(chunk_tvb, CHUNK_FLAGS_OFFSET) & SCTP_DATA_CHUNK_B_BIT;
   u_bit = tvb_get_guint8(chunk_tvb, CHUNK_FLAGS_OFFSET) & SCTP_DATA_CHUNK_U_BIT;
+  stream_id = tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_ID_OFFSET);
+  stream_seq_num = tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET);
   tsn = tvb_get_ntohl(chunk_tvb, DATA_CHUNK_TSN_OFFSET);
 
   if (chunk_tree) {
-    if (is_idata)
-      proto_item_set_len(chunk_item, I_DATA_CHUNK_HEADER_LENGTH);
-    else
-      proto_item_set_len(chunk_item, DATA_CHUNK_HEADER_LENGTH);
+    proto_item_set_len(chunk_item, DATA_CHUNK_HEADER_LENGTH);
     flags_tree  = proto_item_add_subtree(flags_item, ett_sctp_data_chunk_flags);
     proto_tree_add_item(flags_tree, hf_data_chunk_e_bit,             chunk_tvb, CHUNK_FLAGS_OFFSET,                    CHUNK_FLAGS_LENGTH,                    ENC_BIG_ENDIAN);
     proto_tree_add_item(flags_tree, hf_data_chunk_b_bit,             chunk_tvb, CHUNK_FLAGS_OFFSET,                    CHUNK_FLAGS_LENGTH,                    ENC_BIG_ENDIAN);
@@ -3324,17 +3284,9 @@ dissect_data_chunk(tvbuff_t *chunk_tvb,
     proto_tree_add_item(flags_tree, hf_data_chunk_i_bit,             chunk_tvb, CHUNK_FLAGS_OFFSET,                    CHUNK_FLAGS_LENGTH,                    ENC_BIG_ENDIAN);
     tsn_item = proto_tree_add_item(chunk_tree, hf_data_chunk_tsn,    chunk_tvb, DATA_CHUNK_TSN_OFFSET,                 DATA_CHUNK_TSN_LENGTH,                 ENC_BIG_ENDIAN);
     proto_tree_add_item(chunk_tree, hf_data_chunk_stream_id,         chunk_tvb, DATA_CHUNK_STREAM_ID_OFFSET,           DATA_CHUNK_STREAM_ID_LENGTH,           ENC_BIG_ENDIAN);
-    if (is_idata) {
-      proto_tree_add_item(chunk_tree, hf_idata_chunk_reserved, chunk_tvb, I_DATA_CHUNK_RESERVED_OFFSET, I_DATA_CHUNK_RESERVED_LENGTH, ENC_BIG_ENDIAN);
-      proto_tree_add_item(chunk_tree, hf_idata_chunk_mid, chunk_tvb, I_DATA_CHUNK_MID_OFFSET, I_DATA_CHUNK_MID_LENGTH, ENC_BIG_ENDIAN);
-      if (b_bit)
-        proto_tree_add_item(chunk_tree, hf_data_chunk_payload_proto_id,  chunk_tvb, I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET, I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH, ENC_BIG_ENDIAN);
-      else
-        proto_tree_add_item(chunk_tree, hf_idata_chunk_fsn, chunk_tvb, I_DATA_CHUNK_FSN_OFFSET, I_DATA_CHUNK_FSN_LENGTH, ENC_BIG_ENDIAN);
-    } else {
-      proto_tree_add_item(chunk_tree, hf_data_chunk_stream_seq_number, chunk_tvb, DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET,   DATA_CHUNK_STREAM_SEQ_NUMBER_LENGTH,   ENC_BIG_ENDIAN);
-      proto_tree_add_item(chunk_tree, hf_data_chunk_payload_proto_id,  chunk_tvb, DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET, DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH, ENC_BIG_ENDIAN);
-    }
+    proto_tree_add_item(chunk_tree, hf_data_chunk_stream_seq_number, chunk_tvb, DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET,   DATA_CHUNK_STREAM_SEQ_NUMBER_LENGTH,   ENC_BIG_ENDIAN);
+    proto_tree_add_item(chunk_tree, hf_data_chunk_payload_proto_id,  chunk_tvb, DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET, DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH, ENC_BIG_ENDIAN);
+
     proto_item_append_text(chunk_item, "(%s, ", (u_bit) ? "unordered" : "ordered");
     if (b_bit) {
       if (e_bit)
@@ -3348,39 +3300,20 @@ dissect_data_chunk(tvbuff_t *chunk_tvb,
         proto_item_append_text(chunk_item, "middle");
     }
 
-    if (is_idata) {
-      if (b_bit)
-        proto_item_append_text(chunk_item, " segment, TSN: %u, SID: %u, MID: %u, payload length: %u byte%s)",
-                               tvb_get_ntohl(chunk_tvb, DATA_CHUNK_TSN_OFFSET),
-                               tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_ID_OFFSET),
-                               tvb_get_ntohl(chunk_tvb, I_DATA_CHUNK_MID_OFFSET),
-                               chunk_length - I_DATA_CHUNK_HEADER_LENGTH, plurality(chunk_length - I_DATA_CHUNK_HEADER_LENGTH, "", "s"));
-      else
-        proto_item_append_text(chunk_item, " segment, TSN: %u, SID: %u, MID: %u, FSN: %u, payload length: %u byte%s)",
-                               tvb_get_ntohl(chunk_tvb, DATA_CHUNK_TSN_OFFSET),
-                               tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_ID_OFFSET),
-                               tvb_get_ntohl(chunk_tvb, I_DATA_CHUNK_MID_OFFSET),
-                               tvb_get_ntohl(chunk_tvb, I_DATA_CHUNK_FSN_OFFSET),
-                               chunk_length - I_DATA_CHUNK_HEADER_LENGTH, plurality(chunk_length - I_DATA_CHUNK_HEADER_LENGTH, "", "s"));
-    } else
-      proto_item_append_text(chunk_item, " segment, TSN: %u, SID: %u, SSN: %u, PPID: %u, payload length: %u byte%s)",
-                             tvb_get_ntohl(chunk_tvb, DATA_CHUNK_TSN_OFFSET),
-                             tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_ID_OFFSET),
-                             tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET),
-                             payload_proto_id,
-                             chunk_length - DATA_CHUNK_HEADER_LENGTH, plurality(chunk_length - DATA_CHUNK_HEADER_LENGTH, "", "s"));
+    proto_item_append_text(chunk_item, " segment, TSN: %u, SID: %u, SSN: %u, PPID: %u, payload length: %u byte%s)",
+                           tvb_get_ntohl(chunk_tvb, DATA_CHUNK_TSN_OFFSET),
+                           tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_ID_OFFSET),
+                           tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET),
+                           payload_proto_id,
+                           chunk_length - DATA_CHUNK_HEADER_LENGTH, plurality(chunk_length - DATA_CHUNK_HEADER_LENGTH, "", "s"));
   }
 
-  is_retransmission = sctp_tsn(pinfo, chunk_tvb, tsn_item, ha, tsn);
+  is_retransmission = sctp_tsn(pinfo,  chunk_tvb, tsn_item, ha, tsn);
+
+  payload_tvb = tvb_new_subset(chunk_tvb, DATA_CHUNK_PAYLOAD_OFFSET,
+                               MIN(chunk_length - DATA_CHUNK_HEADER_LENGTH, tvb_captured_length_remaining(chunk_tvb, DATA_CHUNK_PAYLOAD_OFFSET)),
+                               MIN(chunk_length - DATA_CHUNK_HEADER_LENGTH, tvb_reported_length_remaining(chunk_tvb, DATA_CHUNK_PAYLOAD_OFFSET)));
 
-  if (is_idata)
-    payload_tvb = tvb_new_subset(chunk_tvb, I_DATA_CHUNK_PAYLOAD_OFFSET,
-                                 MIN(chunk_length - I_DATA_CHUNK_HEADER_LENGTH, tvb_captured_length_remaining(chunk_tvb, I_DATA_CHUNK_PAYLOAD_OFFSET)),
-                                 MIN(chunk_length - I_DATA_CHUNK_HEADER_LENGTH, tvb_reported_length_remaining(chunk_tvb, I_DATA_CHUNK_PAYLOAD_OFFSET)));
-  else
-    payload_tvb = tvb_new_subset(chunk_tvb, DATA_CHUNK_PAYLOAD_OFFSET,
-                                 MIN(chunk_length - DATA_CHUNK_HEADER_LENGTH, tvb_captured_length_remaining(chunk_tvb, DATA_CHUNK_PAYLOAD_OFFSET)),
-                                 MIN(chunk_length - DATA_CHUNK_HEADER_LENGTH, tvb_reported_length_remaining(chunk_tvb, DATA_CHUNK_PAYLOAD_OFFSET)));
   /* Is this a fragment? */
   if (b_bit && e_bit) {
     /* No - just call the subdissector. */
@@ -3449,26 +3382,12 @@ dissect_data_chunk(tvbuff_t *chunk_tvb,
     /* The logic above should ensure this... */
     DISSECTOR_ASSERT(use_reassembly);
 
-    stream_id = tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_ID_OFFSET);
-    if (is_idata) {
-      /* The stream_seq_num variable is used to hold the MID, the tsn variable holds the FSN*/
-      stream_seq_num = tvb_get_ntohl(chunk_tvb, I_DATA_CHUNK_MID_OFFSET);
-      if (b_bit) {
-        tsn = 0;
-        frag_ppid = payload_proto_id;
-      } else {
-        tsn = tvb_get_ntohl(chunk_tvb, I_DATA_CHUNK_FSN_OFFSET);
-        payload_proto_id = frag_ppid;
-      }
-    } else {
-      /* if unordered set stream_seq_num to 0 for easier handling */
-      if (u_bit)
-        stream_seq_num = 0;
-      else
-        stream_seq_num = tvb_get_ntohs(chunk_tvb, DATA_CHUNK_STREAM_SEQ_NUMBER_OFFSET);
-    }
+    /* if unordered set stream_seq_num to 0 for easier handling */
+    if (u_bit)
+      stream_seq_num = 0;
+
     /* start reassembly */
-    return dissect_fragmented_payload(payload_tvb, pinfo, tree, chunk_tree, tsn, payload_proto_id, stream_id, stream_seq_num, b_bit, e_bit, u_bit);
+    return dissect_fragmented_payload(payload_tvb, pinfo, tree, chunk_tree, tsn, payload_proto_id, stream_id, stream_seq_num, b_bit, e_bit);
   }
 
 }
@@ -4331,10 +4250,7 @@ dissect_sctp_chunk(tvbuff_t *chunk_tvb,
   /* now dissect the chunk value */
   switch(type) {
   case SCTP_DATA_CHUNK_ID:
-    result = dissect_data_chunk(chunk_tvb, length, pinfo, tree, chunk_tree, chunk_item, flags_item, ha, FALSE);
-    break;
-  case SCTP_I_DATA_CHUNK_ID:
-    result = dissect_data_chunk(chunk_tvb, length, pinfo, tree, chunk_tree, chunk_item, flags_item, ha, TRUE);
+    result = dissect_data_chunk(chunk_tvb, length, pinfo, tree, chunk_tree, chunk_item, flags_item, ha);
     break;
   case SCTP_INIT_CHUNK_ID:
     dissect_init_chunk(chunk_tvb, length, pinfo, chunk_tree, chunk_item);
@@ -4743,13 +4659,10 @@ proto_register_sctp(void)
 #if 0
     { &hf_cumulative_tsn_ack,                       { "Cumulative TSN Ack",                             "sctp.cumulative_tsn_ack",                              FT_UINT32,  BASE_DEC,  NULL,                                           0x0,                                NULL, HFILL } },
 #endif
-    { &hf_data_chunk_tsn,                           { "Transmission sequence number",                   "sctp.data_tsn",                                        FT_UINT32,  BASE_DEC,  NULL,                                           0x0,                                NULL, HFILL } },
-    { &hf_data_chunk_stream_id,                     { "Stream identifier",                              "sctp.data_sid",                                        FT_UINT16,  BASE_HEX,  NULL,                                           0x0,                                NULL, HFILL } },
+    { &hf_data_chunk_tsn,                           { "TSN",                                            "sctp.data_tsn",                                        FT_UINT32,  BASE_DEC,  NULL,                                           0x0,                                NULL, HFILL } },
+    { &hf_data_chunk_stream_id,                     { "Stream Identifier",                              "sctp.data_sid",                                        FT_UINT16,  BASE_HEX,  NULL,                                           0x0,                                NULL, HFILL } },
     { &hf_data_chunk_stream_seq_number,             { "Stream sequence number",                         "sctp.data_ssn",                                        FT_UINT16,  BASE_DEC,  NULL,                                           0x0,                                NULL, HFILL } },
     { &hf_data_chunk_payload_proto_id,              { "Payload protocol identifier",                    "sctp.data_payload_proto_id",                           FT_UINT32,  BASE_DEC,  VALS(sctp_payload_proto_id_values),             0x0,                                NULL, HFILL } },
-    { &hf_idata_chunk_reserved,                     { "Reserved",                                       "sctp.data_reserved",                                   FT_UINT16,  BASE_DEC,  NULL,                                           0x0,                                NULL, HFILL } },
-    { &hf_idata_chunk_mid,                          { "Message identifier",                             "sctp.data_mid",                                        FT_UINT32,  BASE_DEC,  NULL,                                           0x0,                                NULL, HFILL } },
-    { &hf_idata_chunk_fsn,                          { "Fragment sequence number",                       "sctp.data_fsn",                                        FT_UINT32,  BASE_DEC,  NULL,                                           0x0,                                NULL, HFILL } },
     { &hf_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,              NULL, HFILL } },
     { &hf_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,              NULL, HFILL } },
     { &hf_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,              NULL, HFILL } },
diff --git a/ui/gtk/sctp_chunk_stat.c b/ui/gtk/sctp_chunk_stat.c
index 5742c428cf..e4266e0df2 100644
--- a/ui/gtk/sctp_chunk_stat.c
+++ b/ui/gtk/sctp_chunk_stat.c
@@ -207,12 +207,11 @@ sctpstat_draw(void *phs)
 		12, tmp->chunk_count[SCTP_ABORT_CHUNK_ID],
 		13, tmp->chunk_count[SCTP_ERROR_CHUNK_ID],
 		14, tmp->chunk_count[SCTP_NR_SACK_CHUNK_ID],
-		15, tmp->chunk_count[SCTP_IDATA_CHUNK_ID],
-		16, tmp->chunk_count[SCTP_ASCONF_ACK_CHUNK_ID],
-		17, tmp->chunk_count[SCTP_PKTDROP_CHUNK_ID],
-		18, tmp->chunk_count[SCTP_FORWARD_TSN_CHUNK_ID],
-		19, tmp->chunk_count[SCTP_ASCONF_CHUNK_ID],
-		20, tmp->chunk_count[OTHER_CHUNKS_INDEX],
+		15, tmp->chunk_count[SCTP_ASCONF_ACK_CHUNK_ID],
+		16, tmp->chunk_count[SCTP_PKTDROP_CHUNK_ID],
+		17, tmp->chunk_count[SCTP_FORWARD_TSN_CHUNK_ID],
+		18, tmp->chunk_count[SCTP_ASCONF_CHUNK_ID],
+		19, tmp->chunk_count[OTHER_CHUNKS_INDEX],
 		-1
 		);
 		wmem_free(NULL, src_addr);
@@ -251,7 +250,6 @@ static const stat_column titles[]={
 	{G_TYPE_UINT, TAP_ALIGN_RIGHT,  "ABORT" },
 	{G_TYPE_UINT, TAP_ALIGN_RIGHT,  "ERROR" },
 	{G_TYPE_UINT, TAP_ALIGN_RIGHT,  "NR-SACK" },
-	{G_TYPE_UINT, TAP_ALIGN_RIGHT,  "IDATA" },
 	{G_TYPE_UINT, TAP_ALIGN_RIGHT,  "ASCONF-ACK" },
 	{G_TYPE_UINT, TAP_ALIGN_RIGHT,  "PKTDROP" },
 	{G_TYPE_UINT, TAP_ALIGN_RIGHT,  "FORWARD-TSN" },
diff --git a/ui/gtk/sctp_graph_dlg.c b/ui/gtk/sctp_graph_dlg.c
index 684636b8e0..f702a68491 100644
--- a/ui/gtk/sctp_graph_dlg.c
+++ b/ui/gtk/sctp_graph_dlg.c
@@ -569,7 +569,7 @@ draw_tsn_graph(struct sctp_udata *u_data)
 		while (tlist)
 		{
 			type = ((struct chunk_header *)tlist->data)->type;
-			if (type == SCTP_DATA_CHUNK_ID || type == SCTP_IDATA_CHUNK_ID || type == SCTP_FORWARD_TSN_CHUNK_ID)
+			if (type == SCTP_DATA_CHUNK_ID || type == SCTP_FORWARD_TSN_CHUNK_ID)
 				tsnumber = g_ntohl(((struct data_chunk_header *)tlist->data)->tsn);
 			if (tsnumber >= min_tsn && tsnumber <= max_tsn && tsn->secs >= min_secs)
 			{
@@ -589,7 +589,7 @@ draw_tsn_graph(struct sctp_udata *u_data)
 #else
 					cr = gdk_cairo_create (u_data->io->pixmap);
 #endif
-					if ((type == SCTP_DATA_CHUNK_ID) || (type == SCTP_IDATA_CHUNK_ID))
+					if (type == SCTP_DATA_CHUNK_ID)
 						gdk_cairo_set_source_rgba (cr, &black_color);
 					else
 						gdk_cairo_set_source_rgba (cr, &pink_color);
diff --git a/ui/qt/sctp_graph_arwnd_dialog.cpp b/ui/qt/sctp_graph_arwnd_dialog.cpp
index a36e5bdfbd..abaeb5832a 100644
--- a/ui/qt/sctp_graph_arwnd_dialog.cpp
+++ b/ui/qt/sctp_graph_arwnd_dialog.cpp
@@ -76,10 +76,10 @@ void SCTPGraphArwndDialog::drawArwndGraph()
 
     if (direction == 1) {
         listSACK = g_list_last(selected_assoc->sack1);
-        startArwnd = selected_assoc->arwnd2;
+        startArwnd = selected_assoc->arwnd1;
     } else {
         listSACK = g_list_last(selected_assoc->sack2);
-        startArwnd = selected_assoc->arwnd1;
+        startArwnd = selected_assoc->arwnd2;
     }
     while (listSACK) {
         tsn = (tsn_t*) (listSACK->data);
diff --git a/ui/qt/sctp_graph_byte_dialog.cpp b/ui/qt/sctp_graph_byte_dialog.cpp
index 4af5a847e2..2d24ba73d2 100644
--- a/ui/qt/sctp_graph_byte_dialog.cpp
+++ b/ui/qt/sctp_graph_byte_dialog.cpp
@@ -90,12 +90,8 @@ void SCTPGraphByteDialog::drawBytesGraph()
         while (tlist)
         {
             type = ((struct chunk_header *)tlist->data)->type;
-            if (type == SCTP_DATA_CHUNK_ID || type == SCTP_I_DATA_CHUNK_ID) {
+            if (type == SCTP_DATA_CHUNK_ID) {
                 length = g_ntohs(((struct data_chunk_header *)tlist->data)->length);
-                if (type == SCTP_DATA_CHUNK_ID)
-                    length -= DATA_CHUNK_HEADER_LENGTH;
-                else
-                    length -= I_DATA_CHUNK_HEADER_LENGTH;
                 sumBytes += length;
                 yb.append(sumBytes);
                 xb.append(tsn->secs + tsn->usecs/1000000.0);
diff --git a/ui/qt/sctp_graph_dialog.cpp b/ui/qt/sctp_graph_dialog.cpp
index 2052650d0e..761db06518 100644
--- a/ui/qt/sctp_graph_dialog.cpp
+++ b/ui/qt/sctp_graph_dialog.cpp
@@ -86,8 +86,8 @@ void SCTPGraphDialog::drawNRSACKGraph()
         list = g_list_last(selected_assoc->sack1);
         min_tsn = selected_assoc->min_tsn1;
     } else {
-        list = g_list_last(selected_assoc->sack2);
-        min_tsn = selected_assoc->min_tsn2;
+        list = g_list_last(selected_assoc->sack1);
+        min_tsn = selected_assoc->min_tsn1;
     }
     while (list) {
         sack = (tsn_t*) (list->data);
@@ -280,7 +280,7 @@ void SCTPGraphDialog::drawTSNGraph()
         while (tlist)
         {
             type = ((struct chunk_header *)tlist->data)->type;
-            if (type == SCTP_DATA_CHUNK_ID || type == SCTP_I_DATA_CHUNK_ID || type == SCTP_FORWARD_TSN_CHUNK_ID) {
+            if (type == SCTP_DATA_CHUNK_ID || type == SCTP_FORWARD_TSN_CHUNK_ID) {
                 tsnumber = g_ntohl(((struct data_chunk_header *)tlist->data)->tsn);
                 yt.append(tsnumber);
                 xt.append(tsn->secs + tsn->usecs/1000000.0);
@@ -314,7 +314,6 @@ void SCTPGraphDialog::drawTSNGraph()
 void SCTPGraphDialog::drawGraph(int which)
 {
     guint32 maxTSN, minTSN;
-    gint64 minBound;
 
     gIsSackChunkPresent = false;
     gIsNRSackChunkPresent = false;
@@ -349,12 +348,7 @@ void SCTPGraphDialog::drawGraph(int which)
     connect(ui->sctpPlot, SIGNAL(plottableClick(QCPAbstractPlottable*,QMouseEvent*)), this, SLOT(graphClicked(QCPAbstractPlottable*, QMouseEvent*)));
     // set axes ranges, so we see all data:
     QCPRange myXRange(selected_assoc->min_secs, (selected_assoc->max_secs+1));
-    if (maxTSN - minTSN < 5) {
-        minBound = 0;
-    } else {
-        minBound = minTSN;
-    }
-    QCPRange myYRange(minBound, maxTSN);
+    QCPRange myYRange(minTSN, maxTSN);
     ui->sctpPlot->xAxis->setRange(myXRange);
     ui->sctpPlot->yAxis->setRange(myYRange);
     ui->sctpPlot->replot();
diff --git a/ui/tap-sctp-analysis.c b/ui/tap-sctp-analysis.c
index 6e3db28f4c..6652fe705e 100644
--- a/ui/tap-sctp-analysis.c
+++ b/ui/tap-sctp-analysis.c
@@ -478,7 +478,6 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 			if (((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_INIT_CHUNK_ID) ||
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_INIT_ACK_CHUNK_ID) ||
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_DATA_CHUNK_ID) ||
-			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_I_DATA_CHUNK_ID) ||
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_SACK_CHUNK_ID) ||
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_NR_SACK_CHUNK_ID) ||
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_FORWARD_TSN_CHUNK_ID))
@@ -508,7 +507,6 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 				sack->secs=tsn->secs   = (guint32)pinfo->rel_ts.secs;
 				sack->usecs=tsn->usecs = (guint32)pinfo->rel_ts.nsecs/1000;
 				if (((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_DATA_CHUNK_ID) ||
-				    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_I_DATA_CHUNK_ID) ||
 				    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_SACK_CHUNK_ID) ||
 				    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_NR_SACK_CHUNK_ID) ||
 				    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_FORWARD_TSN_CHUNK_ID))
@@ -585,7 +583,6 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 				if (((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_INIT_CHUNK_ID) &&
 				    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_INIT_ACK_CHUNK_ID) &&
 				    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_DATA_CHUNK_ID) &&
-				    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_I_DATA_CHUNK_ID) &&
 				    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_SACK_CHUNK_ID) &&
 				    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_NR_SACK_CHUNK_ID) &&
 				    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_FORWARD_TSN_CHUNK_ID))
@@ -607,15 +604,10 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 					info->ep1_chunk_count[idx]++;
 					info = add_chunk_count(&tmp_info.src, info, 1, idx);
 
-					if ((tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_DATA_CHUNK_ID) ||
-						(tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_I_DATA_CHUNK_ID))
+					if ((tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_DATA_CHUNK_ID))
 					{
 						datachunk = TRUE;
-						if (tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_DATA_CHUNK_ID) {
-							length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET) - DATA_CHUNK_HEADER_LENGTH;
-						} else {
-							length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET) - I_DATA_CHUNK_HEADER_LENGTH;
-						}
+						length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET)-DATA_CHUNK_HEADER_LENGTH;
 						info->n_data_chunks++;
 						info->n_data_bytes+=length;
 						info->outstream1 = tvb_get_ntohs((sctp_info->tvb)[chunk_number], DATA_CHUNK_STREAM_ID_OFFSET)+1;
@@ -663,11 +655,7 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 						tsn_s->offset   = 0;
 						tsn_s->framenumber = framenumber;
 						if (datachunk)
-							if (tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_DATA_CHUNK_ID) {
-								tsn_s->length   = length - DATA_CHUNK_HEADER_LENGTH;
-							} else {
-								tsn_s->length   = length - I_DATA_CHUNK_HEADER_LENGTH;
-							}
+							tsn_s->length   = length-DATA_CHUNK_HEADER_LENGTH;
 						else
 							tsn_s->length   = length;
 						if (tsn->secs < info->min_secs)
@@ -793,7 +781,6 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 		if (((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_INIT_CHUNK_ID) ||
 		    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_INIT_ACK_CHUNK_ID) ||
 		    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_DATA_CHUNK_ID) ||
-		    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_I_DATA_CHUNK_ID) ||
 		    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_SACK_CHUNK_ID) ||
 		    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_NR_SACK_CHUNK_ID) ||
 		    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_FORWARD_TSN_CHUNK_ID))
@@ -824,7 +811,6 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 			sack->secs=tsn->secs = (guint32)pinfo->rel_ts.secs;
 			sack->usecs=tsn->usecs = (guint32)pinfo->rel_ts.nsecs/1000;
 			if (((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_DATA_CHUNK_ID) ||
-			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_I_DATA_CHUNK_ID) ||
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_SACK_CHUNK_ID) ||
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_NR_SACK_CHUNK_ID) ||
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) == SCTP_FORWARD_TSN_CHUNK_ID))
@@ -946,7 +932,6 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 		{
 			if (((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_INIT_ACK_CHUNK_ID) &&
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_DATA_CHUNK_ID) &&
-			    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_I_DATA_CHUNK_ID) &&
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_SACK_CHUNK_ID) &&
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_NR_SACK_CHUNK_ID) &&
 			    ((tvb_get_guint8(sctp_info->tvb[0],0)) != SCTP_FORWARD_TSN_CHUNK_ID))
@@ -971,10 +956,9 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 					info->ep2_chunk_count[idx]++;
 				info = add_chunk_count(&tmp_info.src, info,info->direction, idx);
 
-				if ((tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_DATA_CHUNK_ID) ||
-				    (tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_I_DATA_CHUNK_ID))
+				if (((tvb_get_guint8(sctp_info->tvb[chunk_number],0)) == SCTP_DATA_CHUNK_ID))
 					datachunk = TRUE;
-				if (tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_FORWARD_TSN_CHUNK_ID)
+				if (((tvb_get_guint8(sctp_info->tvb[chunk_number],0)) == SCTP_FORWARD_TSN_CHUNK_ID))
 					forwardchunk = TRUE;
 				if ((datachunk || forwardchunk) && tsn != NULL)
 				{
@@ -985,11 +969,7 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 					{
 						t_s_n = (guint8 *)g_malloc(16);
 						tvb_memcpy(sctp_info->tvb[chunk_number], (guint8 *)(t_s_n),0, 16);
-						if (tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_DATA_CHUNK_ID) {
-							length=tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET)-DATA_CHUNK_HEADER_LENGTH;
-						} else {
-							length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET) - I_DATA_CHUNK_HEADER_LENGTH;
-						}
+						length=tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET)-DATA_CHUNK_HEADER_LENGTH;
 						info->n_data_chunks++;
 						info->n_data_bytes+=length;
 					}
@@ -1076,11 +1056,7 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 						{
 							if (datachunk)
 							{
-								if (tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_DATA_CHUNK_ID) {
-									length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET) - DATA_CHUNK_HEADER_LENGTH;
-								} else {
-									length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET) - I_DATA_CHUNK_HEADER_LENGTH;
-								}
+								length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET)-DATA_CHUNK_HEADER_LENGTH;
 								info->n_data_chunks_ep2++;
 								info->n_data_bytes_ep2+=length;
 							}
@@ -1094,11 +1070,7 @@ packet(void *tapdata _U_, packet_info *pinfo, epan_dissect_t *edt _U_, const voi
 							info->max_tsn2 = tsnumber;
 							if (datachunk)
 							{
-								if (tvb_get_guint8(sctp_info->tvb[chunk_number],0) == SCTP_DATA_CHUNK_ID) {
-									length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET) - DATA_CHUNK_HEADER_LENGTH;
-								} else {
-									length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET) - I_DATA_CHUNK_HEADER_LENGTH;
-								}
+								length = tvb_get_ntohs(sctp_info->tvb[chunk_number], CHUNK_LENGTH_OFFSET)-DATA_CHUNK_HEADER_LENGTH;
 								info->n_data_chunks_ep2++;
 								info->n_data_bytes_ep2+=length;
 							}
diff --git a/ui/tap-sctp-analysis.h b/ui/tap-sctp-analysis.h
index 8c939fbb4b..b7fabd19db 100644
--- a/ui/tap-sctp-analysis.h
+++ b/ui/tap-sctp-analysis.h
@@ -56,7 +56,6 @@ extern "C" {
 #define SCTP_SHUTDOWN_COMPLETE_CHUNK_ID 14
 #define SCTP_AUTH_CHUNK_ID		15
 #define SCTP_NR_SACK_CHUNK_ID		16
-#define SCTP_I_DATA_CHUNK_ID          0x40
 #define SCTP_ASCONF_ACK_CHUNK_ID      0x80
 #define SCTP_PKTDROP_CHUNK_ID	      0x81
 #define SCTP_RE_CONFIG_CHUNK_ID	      0x82
@@ -66,7 +65,7 @@ extern "C" {
 #define SCTP_IETF_EXT		      0xFF
 
 #define IS_SCTP_CHUNK_TYPE(t) \
-	(((t) <= 17) || ((t) == 0x40) || ((t) == 0xC0) || ((t) == 0xC1) || ((t) == 0x80) || ((t) == 0x81))
+	(((t) <= 16) || ((t) == 0xC0) || ((t) == 0xC1) || ((t) == 0x80) || ((t) == 0x81))
 
 #define CHUNK_TYPE_LENGTH	      1
 #define CHUNK_FLAGS_LENGTH	      1
@@ -100,31 +99,11 @@ extern "C" {
 #define DATA_CHUNK_STREAM_ID_LENGTH   2
 #define DATA_CHUNK_STREAM_SEQ_NUMBER_LENGTH 2
 #define DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH 4
-#define I_DATA_CHUNK_RESERVED_LENGTH 2
-#define I_DATA_CHUNK_MID_LENGTH 4
-#define I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH 4
-#define I_DATA_CHUNK_FSN_LENGTH 4
-#define I_DATA_CHUNK_RESERVED_OFFSET  (DATA_CHUNK_STREAM_ID_OFFSET + \
-                                       DATA_CHUNK_STREAM_ID_LENGTH)
-#define I_DATA_CHUNK_MID_OFFSET       (I_DATA_CHUNK_RESERVED_OFFSET + \
-                                       I_DATA_CHUNK_RESERVED_LENGTH)
-#define I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET (I_DATA_CHUNK_MID_OFFSET + \
-                                                 I_DATA_CHUNK_MID_LENGTH)
-#define I_DATA_CHUNK_FSN_OFFSET       (I_DATA_CHUNK_MID_OFFSET + \
-                                       I_DATA_CHUNK_MID_LENGTH)
-#define I_DATA_CHUNK_PAYLOAD_OFFSET   (I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_OFFSET + \
-                                       I_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 I_DATA_CHUNK_HEADER_LENGTH    (CHUNK_HEADER_LENGTH + \
-                                       DATA_CHUNK_TSN_LENGTH + \
-                                       DATA_CHUNK_STREAM_ID_LENGTH + \
-                                       I_DATA_CHUNK_RESERVED_LENGTH + \
-                                       I_DATA_CHUNK_MID_LENGTH +\
-                                       I_DATA_CHUNK_PAYLOAD_PROTOCOL_ID_LENGTH)
 #define MAX_ADDRESS_LEN		       47
 
 #define SCTP_ABORT_CHUNK_T_BIT	      0x01
@@ -180,8 +159,7 @@ static const value_string chunk_type_values[] = {
 	{ SCTP_CWR_CHUNK_ID,		   "CWR" },
 	{ SCTP_SHUTDOWN_COMPLETE_CHUNK_ID, "SHUTDOWN_COMPLETE" },
 	{ SCTP_AUTH_CHUNK_ID,		   "AUTH" },
-	{ SCTP_NR_SACK_CHUNK_ID,	   "NR_SACK" },
-	{ SCTP_I_DATA_CHUNK_ID,             "I_DATA" },
+	{ SCTP_NR_SACK_CHUNK_ID,	   "NR-SACK" },
 	{ SCTP_ASCONF_ACK_CHUNK_ID,	   "ASCONF_ACK" },
 	{ SCTP_PKTDROP_CHUNK_ID,	   "PKTDROP" },
 	{ SCTP_RE_CONFIG_CHUNK_ID,	   "RE_CONFIG" },