RTPS: Added Topic Information feature. This feature shows the Topic

Name and the Type Name of the sample by consulting a hash table
that relates GUIDs and this information.

This information is very useful to any analysis performed to RTPS
data. It can be disabled using a checkbox so it doesn't impact
performance when capturing (default = disabled).

Bug: 11729
Change-Id: Ic9fa3a777dfed3cb46166b8e7c9783a12c161e7d
Reviewed-on: https://code.wireshark.org/review/11602
Petri-Dish: Pascal Quantin <pascal.quantin@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>

1 files changed, 172 insertions, 29 deletions

diff --git a/epan/dissectors/packet-rtps.c b/epan/dissectors/packet-rtps.c
index 73946c7a8c..e275375a7e 100644
--- a/epan/dissectors/packet-rtps.c
+++ b/epan/dissectors/packet-rtps.c
@@ -373,6 +373,7 @@ static gint ett_rtps_app_ack_virtual_writer                     = -1;
 static gint ett_rtps_product_version                            = -1;
 static gint ett_rtps_property_list                              = -1;
 static gint ett_rtps_property                                   = -1;
+static gint ett_rtps_topic_info                                 = -1;
 
 static expert_field ei_rtps_sm_octets_to_next_header_error = EI_INIT;
 static expert_field ei_rtps_port_invalid = EI_INIT;
@@ -390,6 +391,7 @@ static expert_field ei_rtps_unsupported_non_builtin_param_seq    = EI_INIT;
 /* Preferences                                                             */
 /***************************************************************************/
 static guint rtps_max_batch_samples_dissected = 16;
+static gboolean enable_topic_info = FALSE;
 
 /***************************************************************************/
 /* Value-to-String Tables */
@@ -1150,6 +1152,22 @@ static const int* NACK_FLAGS[] = {
 };
 #endif
 
+typedef struct _endpoint_guid {
+  guint32 host_id;
+  guint32 app_id;
+  guint32 instance_id;
+  guint32 entity_id;
+} endpoint_guid;
+
+#define MAX_TOPIC_AND_TYPE_LENGTH 256
+typedef struct _type_mapping {
+  endpoint_guid guid;
+  gchar type_name[MAX_TOPIC_AND_TYPE_LENGTH];
+  gchar topic_name[MAX_TOPIC_AND_TYPE_LENGTH];
+  gint fields_visited;
+} type_mapping;
+
+static wmem_map_t * registry = NULL;
 
 /***************************************************************************/
 /* Inline macros */
@@ -2760,6 +2778,82 @@ static int rtps_util_add_fragment_number_set(proto_tree *tree, packet_info *pinf
   return offset;
 }
 
+static void rtps_util_store_type_mapping(tvbuff_t *tvb, gint offset,
+        type_mapping * type_mapping_object, const gchar * value,
+        gint topic_info_add_id) {
+  if (enable_topic_info && type_mapping_object) {
+    switch (topic_info_add_id) {
+      case TOPIC_INFO_ADD_GUID: {
+        type_mapping_object->guid.host_id = tvb_get_ntohl(tvb, offset);
+        type_mapping_object->guid.app_id = tvb_get_ntohl(tvb, offset+4);
+        type_mapping_object->guid.instance_id = tvb_get_ntohl(tvb, offset+8);
+        type_mapping_object->guid.entity_id = tvb_get_ntohl(tvb, offset+12);
+        type_mapping_object->fields_visited =
+                type_mapping_object->fields_visited | TOPIC_INFO_ADD_GUID;
+        break;
+      }
+      case TOPIC_INFO_ADD_TOPIC_NAME: {
+        g_strlcpy(type_mapping_object->topic_name, value, MAX_TOPIC_AND_TYPE_LENGTH);
+        type_mapping_object->fields_visited =
+                type_mapping_object->fields_visited | TOPIC_INFO_ADD_TOPIC_NAME;
+        break;
+      }
+      case TOPIC_INFO_ADD_TYPE_NAME: {
+        g_strlcpy(type_mapping_object->type_name, value, MAX_TOPIC_AND_TYPE_LENGTH);
+        type_mapping_object->fields_visited =
+                type_mapping_object->fields_visited | TOPIC_INFO_ADD_TYPE_NAME;
+        break;
+      }
+      default:
+        break;
+    }
+    if ((type_mapping_object->fields_visited & TOPIC_INFO_ALL_SET) == TOPIC_INFO_ALL_SET &&
+            !wmem_map_lookup(registry, &(type_mapping_object->guid))) {
+      if (((type_mapping_object->guid.entity_id & 0x02) == 0x02)){
+        /* If it is an application defined writer matches 0x02 */
+        wmem_map_insert(registry, &(type_mapping_object->guid), type_mapping_object);
+      }
+    }
+  }
+}
+guint hash_by_guid(gconstpointer key) {
+  endpoint_guid * guid = (endpoint_guid *) key;
+  return g_int_hash(&(guid->app_id));
+}
+
+gboolean compare_by_guid(gconstpointer a, gconstpointer b) {
+  endpoint_guid * guid_a = (endpoint_guid *) a;
+  endpoint_guid * guid_b = (endpoint_guid *) b;
+  return memcmp(guid_a, guid_b, sizeof(endpoint_guid)) == 0;
+}
+
+static type_mapping * rtps_util_get_topic_info(endpoint_guid * guid) {
+  /* At this point, we know the boolean enable_topic_info is true */
+  type_mapping * result = NULL;
+  if (guid)
+    result = (type_mapping *)wmem_map_lookup(registry, guid);
+  return result;
+}
+
+static void rtps_util_show_topic_info(proto_tree *tree, tvbuff_t *tvb,
+        gint offset, endpoint_guid * guid) {
+  if (enable_topic_info && tree) {
+    type_mapping * type_mapping_object = rtps_util_get_topic_info(guid);
+    if (type_mapping_object != NULL) {
+      proto_tree * topic_info_tree;
+      proto_item * ti;
+      topic_info_tree = proto_tree_add_subtree(tree, tvb, offset, 0,
+                ett_rtps_topic_info, NULL, "[Topic Information (from Discovery)]");
+      ti = proto_tree_add_string(topic_info_tree, hf_rtps_param_topic_name, tvb, offset, 0,
+            type_mapping_object->topic_name);
+      PROTO_ITEM_SET_GENERATED(ti);
+      ti = proto_tree_add_string(topic_info_tree, hf_rtps_param_type_name, tvb, offset, 0,
+            type_mapping_object->type_name);
+      PROTO_ITEM_SET_GENERATED(ti);
+    }
+  }
+}
+
 /* *********************************************************************** */
 /* * Parameter Sequence dissector                                        * */
 /* *********************************************************************** */
@@ -2780,12 +2874,10 @@ static int rtps_util_add_fragment_number_set(proto_tree *tree, packet_info *pinf
 
 static gboolean dissect_parameter_sequence_rti(proto_tree *rtps_parameter_tree, packet_info *pinfo, tvbuff_t *tvb,
   proto_item *parameter_item, proto_item * param_len_item, gint offset,
-  gboolean little_endian, int param_length,
-  guint16 parameter) {
+  gboolean little_endian, int param_length, guint16 parameter) {
 
   switch(parameter) {
 
-
     /* 0...2...........7...............15.............23...............31
     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     * | PID_DEFAULT_MULTICAST_LOCATOR |            0x0018             |
@@ -3173,7 +3265,7 @@ static gboolean dissect_parameter_sequence_toc(proto_tree *rtps_parameter_tree,
 static gboolean dissect_parameter_sequence_v1(proto_tree *rtps_parameter_tree, packet_info *pinfo, tvbuff_t *tvb,
                         proto_item *parameter_item, proto_item * param_len_item, gint offset,
                         gboolean little_endian, int size, int param_length,
-                        guint16 parameter, guint16 version) {
+                        guint16 parameter, guint16 version, type_mapping * type_mapping_object) {
   proto_tree *subtree;
 
   switch(parameter) {
@@ -3220,10 +3312,17 @@ static gboolean dissect_parameter_sequence_v1(proto_tree *rtps_parameter_tree, p
      * |                              ...                              |
      * +---------------+---------------+---------------+---------------+
      */
-    case PID_TOPIC_NAME:
+    case PID_TOPIC_NAME: {
+      const gchar * retVal = NULL;
+      guint32 str_size = NEXT_guint32(tvb, offset, little_endian);
+
+      retVal = (gchar*)tvb_get_string_enc(wmem_packet_scope(), tvb, offset+4, str_size, ENC_ASCII);
+
+      rtps_util_store_type_mapping(tvb, offset, type_mapping_object, retVal, TOPIC_INFO_ADD_TOPIC_NAME);
+
       rtps_util_add_string(rtps_parameter_tree, tvb, offset, hf_rtps_param_topic_name, little_endian);
       break;
-
+    }
 
     /* 0...2...........7...............15.............23...............31
      * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -3249,9 +3348,17 @@ static gboolean dissect_parameter_sequence_v1(proto_tree *rtps_parameter_tree, p
      * |                              ...                              |
      *  +---------------+---------------+---------------+---------------+
      */
-    case PID_TYPE_NAME:
+    case PID_TYPE_NAME: {
+      const gchar * retVal = NULL;
+      guint32 str_size = NEXT_guint32(tvb, offset, little_endian);
+
+      retVal = (gchar*) tvb_get_string_enc(wmem_packet_scope(), tvb, offset+4, str_size, ENC_ASCII);
+
+      rtps_util_store_type_mapping(tvb, offset, type_mapping_object, retVal, TOPIC_INFO_ADD_TYPE_NAME);
+
       rtps_util_add_string(rtps_parameter_tree, tvb, offset, hf_rtps_param_type_name, little_endian);
       break;
+    }
 
     /* 0...2...........7...............15.............23...............31
      * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -4124,7 +4231,8 @@ static gboolean dissect_parameter_sequence_v1(proto_tree *rtps_parameter_tree, p
 static gboolean dissect_parameter_sequence_v2(proto_tree *rtps_parameter_tree, packet_info *pinfo, tvbuff_t *tvb,
                         proto_item *parameter_item _U_, proto_item *param_len_item,
                         gint offset, gboolean little_endian, int param_length,
-                        guint16 parameter, guint32 *pStatusInfo, guint16 vendor_id _U_) {
+                        guint16 parameter, guint32 *pStatusInfo, guint16 vendor_id _U_,
+                        type_mapping * type_mapping_object) {
   proto_item *ti;
 
   switch(parameter) {
@@ -4347,6 +4455,7 @@ static gboolean dissect_parameter_sequence_v2(proto_tree *rtps_parameter_tree, p
      */
     case PID_ENDPOINT_GUID:
       ENSURE_LENGTH(16);
+      rtps_util_store_type_mapping(tvb, offset, type_mapping_object, NULL, TOPIC_INFO_ADD_GUID);
       rtps_util_add_generic_guid_v2(rtps_parameter_tree, tvb, offset,
                     hf_rtps_endpoint_guid, hf_rtps_param_host_id, hf_rtps_param_app_id,
                     hf_rtps_param_instance_id, hf_rtps_param_app_kind, hf_rtps_param_counter,
@@ -4370,6 +4479,10 @@ static gint dissect_parameter_sequence(proto_tree *tree, packet_info *pinfo, tvb
   guint16    parameter, param_length;
   gint       original_offset = offset;
   gboolean   dissect_return_value = FALSE;
+  type_mapping * type_mapping_object = NULL;
+
+  if (!pinfo->fd->flags.visited)
+    type_mapping_object = wmem_new(wmem_file_scope(), type_mapping);
 
   rtps_parameter_sequence_tree = proto_tree_add_subtree_format(tree, tvb, offset, -1, ett_rtps_parameter_sequence, &ti, "%s:", label);
 
@@ -4442,11 +4555,11 @@ static gint dissect_parameter_sequence(proto_tree *tree, packet_info *pinfo, tvb
 
     if (!dissect_return_value) {
       if (!dissect_parameter_sequence_v1(rtps_parameter_tree, pinfo, tvb, param_item, param_len_item,
-        offset, little_endian, size, param_length, parameter, version)) {
+        offset, little_endian, size, param_length, parameter, version, type_mapping_object)) {
           if ((version < 0x0200) ||
             !dissect_parameter_sequence_v2(rtps_parameter_tree, pinfo, tvb, param_item, param_len_item,
             offset, little_endian, param_length, parameter,
-            pStatusInfo, vendor_id)) {
+            pStatusInfo, vendor_id, type_mapping_object)) {
               if (param_length > 0) {
                 proto_tree_add_item(rtps_parameter_tree, hf_rtps_parameter_data, tvb,
                         offset, param_length, ENC_NA);
@@ -4614,7 +4727,8 @@ static void dissect_APP_ACK_CONF(tvbuff_t *tvb,
  * type specified the type of endianess of the payload.
  */
 static void dissect_serialized_data(proto_tree *tree, packet_info *pinfo, tvbuff_t *tvb, gint offset,
-                        int  size, const char *label, guint16 vendor_id, gboolean is_discovery_data) {
+                        int  size, const char *label, guint16 vendor_id, gboolean is_discovery_data,
+                        endpoint_guid * guid) {
   proto_item *ti;
   proto_tree *rtps_parameter_sequence_tree;
   guint16 encapsulation_id;
@@ -4623,6 +4737,9 @@ static void dissect_serialized_data(proto_tree *tree, packet_info *pinfo, tvbuff
   /* Creates the sub-tree */
   rtps_parameter_sequence_tree = proto_tree_add_subtree(tree, tvb, offset, -1, ett_rtps_serialized_data, &ti, label);
 
+  /* Add Topic Information if enabled (checked inside)*/
+  rtps_util_show_topic_info(rtps_parameter_sequence_tree, tvb, offset, guid);
+
   /* Encapsulation ID */
   encapsulation_id =  NEXT_guint16(tvb, offset, ENC_BIG_ENDIAN);   /* Always big endian */
   proto_tree_add_uint(rtps_parameter_sequence_tree, hf_rtps_param_serialize_encap_kind, tvb, offset, 2, encapsulation_id);
@@ -4658,7 +4775,7 @@ static void dissect_serialized_data(proto_tree *tree, packet_info *pinfo, tvbuff
           break;
 
     default:
-    proto_tree_add_item(rtps_parameter_sequence_tree, hf_rtps_data_serialize_data, tvb,
+        proto_tree_add_item(rtps_parameter_sequence_tree, hf_rtps_data_serialize_data, tvb,
                         offset, size, ENC_NA);
   }
 }
@@ -4842,7 +4959,8 @@ static void dissect_APP_ACK(tvbuff_t *tvb,
             interval_payload_length,
             "payload",
             vendor_id,
-            FALSE /* from_builtin_writer */);
+            FALSE /* from_builtin_writer */,
+            NULL /* guid pointer */);
           offset += interval_payload_length;
         }
 
@@ -5086,7 +5204,7 @@ static void dissect_DATA_v1(tvbuff_t *tvb, packet_info *pinfo, gint offset, guin
 
 static void dissect_DATA_v2(tvbuff_t *tvb, packet_info *pinfo, gint offset, guint8 flags,
                             gboolean little_endian, int octets_to_next_header, proto_tree *tree,
-                            guint16 vendor_id) {
+                            guint16 vendor_id, endpoint_guid *guid) {
   /*
    *
    * 0...2...........7...............15.............23...............31
@@ -5193,9 +5311,10 @@ static void dissect_DATA_v2(tvbuff_t *tvb, packet_info *pinfo, gint offset, guin
   if ((flags & FLAG_DATA_D_v2) != 0) {
     from_builtin_writer =
         (((wid & 0xc2) == 0xc2) || ((wid & 0xc3) == 0xc3)) ? TRUE : FALSE;
+    guid->entity_id = wid;
     dissect_serialized_data(tree, pinfo, tvb, offset,
                         octets_to_next_header - (offset - old_offset) + 4,
-                        "serializedData", vendor_id, from_builtin_writer);
+                        "serializedData", vendor_id, from_builtin_writer, guid);
   }
   info_summary_append_ex(pinfo, wid, status_info);
 }
@@ -5323,7 +5442,7 @@ static void dissect_DATA_FRAG(tvbuff_t *tvb, packet_info *pinfo, gint offset, gu
         (((wid & 0xc2) == 0xc2) || ((wid & 0xc3) == 0xc3)) ? TRUE : FALSE;
     dissect_serialized_data(tree, pinfo, tvb, offset,
                         octets_to_next_header - (offset - old_offset) + 4,
-                        "serializedData", vendor_id, from_builtin_writer);
+                        "serializedData", vendor_id, from_builtin_writer, NULL);
   }
 }
 
@@ -5460,7 +5579,7 @@ static void dissect_NOKEY_DATA(tvbuff_t *tvb, packet_info *pinfo, gint offset, g
         (((wid & 0xc2) == 0xc2) || ((wid & 0xc3) == 0xc3)) ? TRUE : FALSE;
     dissect_serialized_data(tree, pinfo, tvb, offset,
                         octets_to_next_header - (offset - old_offset) + 4,
-                        "serializedData", vendor_id, from_builtin_writer);
+                        "serializedData", vendor_id, from_builtin_writer, NULL);
   }
 
 }
@@ -5563,7 +5682,7 @@ static void dissect_NOKEY_DATA_FRAG(tvbuff_t *tvb, packet_info *pinfo, gint offs
       (((wid & 0xc2) == 0xc2) || ((wid & 0xc3) == 0xc3)) ? TRUE : FALSE;
     dissect_serialized_data(tree, pinfo, tvb,offset,
                         octets_to_next_header - (offset - old_offset) + 4,
-                        "serializedData", vendor_id, from_builtin_writer);
+                        "serializedData", vendor_id, from_builtin_writer, NULL);
   }
 }
 
@@ -6263,7 +6382,7 @@ static void dissect_HEARTBEAT_FRAG(tvbuff_t *tvb, packet_info *pinfo, gint offse
 /* *********************************************************************** */
 static void dissect_RTPS_DATA(tvbuff_t *tvb, packet_info *pinfo, gint offset, guint8 flags,
                 gboolean little_endian, int octets_to_next_header, proto_tree *tree,
-                guint16 vendor_id, gboolean is_session) {
+                guint16 vendor_id, gboolean is_session, endpoint_guid * guid) {
   /*
    *
    * 0...2...........7...............15.............23...............31
@@ -6448,11 +6567,11 @@ static void dissect_RTPS_DATA(tvbuff_t *tvb, packet_info *pinfo, gint offset, gu
 
       from_builtin_writer =
         (((wid & 0xc2) == 0xc2) || ((wid & 0xc3) == 0xc3)) ? TRUE : FALSE;
-
+      guid->entity_id = wid;
       /* At the end still dissect the rest of the bytes as raw data */
       dissect_serialized_data(tree, pinfo, tvb, offset,
                         octets_to_next_header - (offset - old_offset) + 4,
-                        label, vendor_id, from_builtin_writer);
+                        label, vendor_id, from_builtin_writer, guid);
     }
   }
 
@@ -6581,7 +6700,7 @@ static void dissect_RTPS_DATA_FRAG(tvbuff_t *tvb, packet_info *pinfo, gint offse
 
     dissect_serialized_data(tree, pinfo, tvb, offset,
                         octets_to_next_header - (offset - old_offset) + 4,
-                        label, vendor_id, from_builtin_writer);
+                        label, vendor_id, from_builtin_writer, NULL);
   }
   info_summary_append_ex(pinfo, wid, status_info);
 }
@@ -7279,7 +7398,8 @@ static void dissect_INFO_REPLY(tvbuff_t *tvb, packet_info *pinfo, gint offset, g
 
 static gboolean dissect_rtps_submessage_v2(tvbuff_t *tvb, packet_info *pinfo, gint offset, guint8 flags,
                                            gboolean little_endian, guint8 submessageId, guint16 vendor_id, gint octets_to_next_header,
-                                           proto_tree *rtps_submessage_tree, proto_item *submessage_item)
+                                           proto_tree *rtps_submessage_tree, proto_item *submessage_item,
+                                           endpoint_guid * guid)
 {
   switch (submessageId)
   {
@@ -7324,7 +7444,7 @@ static gboolean dissect_rtps_submessage_v2(tvbuff_t *tvb, packet_info *pinfo, gi
     case SUBMESSAGE_RTPS_DATA_SESSION:
     case SUBMESSAGE_RTPS_DATA:
       dissect_RTPS_DATA(tvb, pinfo, offset, flags, little_endian, octets_to_next_header,
-              rtps_submessage_tree, vendor_id, (submessageId == SUBMESSAGE_RTPS_DATA_SESSION));
+              rtps_submessage_tree, vendor_id, (submessageId == SUBMESSAGE_RTPS_DATA_SESSION), guid);
       break;
 
     case SUBMESSAGE_RTPS_DATA_FRAG:
@@ -7346,7 +7466,8 @@ static gboolean dissect_rtps_submessage_v2(tvbuff_t *tvb, packet_info *pinfo, gi
 
 static gboolean dissect_rtps_submessage_v1(tvbuff_t *tvb, packet_info *pinfo, gint offset, guint8 flags, gboolean little_endian,
                                            guint8 submessageId, guint16 version, guint16 vendor_id, gint octets_to_next_header,
-                                           proto_tree *rtps_submessage_tree, proto_item *submessage_item)
+                                           proto_tree *rtps_submessage_tree, proto_item *submessage_item,
+                                           endpoint_guid * guid)
 {
   switch (submessageId)
   {
@@ -7356,9 +7477,11 @@ static gboolean dissect_rtps_submessage_v1(tvbuff_t *tvb, packet_info *pinfo, gi
 
     case SUBMESSAGE_DATA:
       if (version < 0x0200) {
-        dissect_DATA_v1(tvb, pinfo, offset, flags, little_endian, octets_to_next_header, rtps_submessage_tree);
+        dissect_DATA_v1(tvb, pinfo, offset, flags, little_endian,
+                octets_to_next_header, rtps_submessage_tree);
       } else {
-        dissect_DATA_v2(tvb, pinfo, offset, flags, little_endian, octets_to_next_header, rtps_submessage_tree, vendor_id);
+        dissect_DATA_v2(tvb, pinfo, offset, flags, little_endian,
+                octets_to_next_header, rtps_submessage_tree, vendor_id, guid);
       }
       break;
 
@@ -7419,6 +7542,7 @@ static gboolean dissect_rtps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree
   gint         next_submsg, octets_to_next_header;
   int          sub_hf;
   const value_string *sub_vals;
+  endpoint_guid guid;
 
   /* Check 'RTPS' signature:
    * A header is invalid if it has less than 16 octets
@@ -7459,6 +7583,10 @@ static gboolean dissect_rtps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree
       rtps_util_add_guid_prefix_v2(rtps_tree, tvb, offset+8, hf_rtps_guid_prefix,
                         hf_rtps_host_id, hf_rtps_app_id, hf_rtps_sm_counter, NULL);
 
+    guid.host_id = tvb_get_ntohl(tvb, offset+8);
+    guid.app_id = tvb_get_ntohl(tvb, offset+12);
+    guid.instance_id = tvb_get_ntohl(tvb, offset+16);
+
 #ifdef RTI_BUILD
     pinfo->guid_prefix_host = tvb_get_ntohl(tvb, offset + 8);
     pinfo->guid_prefix_app  = tvb_get_ntohl(tvb, offset + 12);
@@ -7598,10 +7726,10 @@ static gboolean dissect_rtps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree
      */
     if (!dissect_rtps_submessage_v1(tvb, pinfo, offset, flags, little_endian,
                                     submessageId, version, vendor_id,
-                                    octets_to_next_header, rtps_submessage_tree, ti)) {
+                                    octets_to_next_header, rtps_submessage_tree, ti, &guid)) {
       if ((version < 0x0200) ||
           !dissect_rtps_submessage_v2(tvb, pinfo, offset, flags, little_endian, submessageId,
-                                      vendor_id, octets_to_next_header, rtps_submessage_tree, ti)) {
+                                      vendor_id, octets_to_next_header, rtps_submessage_tree, ti, &guid)) {
         proto_tree_add_uint(rtps_submessage_tree, hf_rtps_sm_flags,
                               tvb, offset + 1, 1, flags);
         proto_tree_add_uint(rtps_submessage_tree,
@@ -7638,6 +7766,13 @@ static gboolean dissect_rtps_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *
   return dissect_rtps(tvb, pinfo, tree, offset);
 }
 
+static void
+rtps_init(void)
+{
+    if (enable_topic_info)
+      registry = wmem_map_new(wmem_file_scope(), hash_by_guid, compare_by_guid);
+}
+
 void proto_register_rtps(void) {
 
   static hf_register_info hf[] = {
@@ -9282,6 +9417,7 @@ void proto_register_rtps(void) {
     &ett_rtps_transport_info,
     &ett_rtps_property_list,
     &ett_rtps_property,
+    &ett_rtps_topic_info,
   };
 
   static ei_register_info ei[] = {
@@ -9318,6 +9454,13 @@ void proto_register_rtps(void) {
             "a DATA_BATCH submessage. Increasing this value may affect "
             "performances if the trace has a lot of big batched samples.",
             10, &rtps_max_batch_samples_dissected);
+
+  prefs_register_bool_preference(rtps_module, "enable_topic_info",
+              "Enable Topic Information feature",
+              "Shows the Topic Name and Type Name of the samples.",
+              &enable_topic_info);
+  register_init_routine(rtps_init);
+
 }