Adding upstream version 4.2.2.upstream/4.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1546 insertions, 0 deletions

diff --git a/epan/dissectors/packet-mongo.c b/epan/dissectors/packet-mongo.c
new file mode 100644
index 00000000..64e6747b
--- /dev/null
+++ b/epan/dissectors/packet-mongo.c
@@ -0,0 +1,1546 @@
+/* packet-mongo.c
+ * Routines for Mongo Wire Protocol dissection
+ * Copyright 2010, Alexis La Goutte <alexis.lagoutte at gmail dot com>
+ * BSON dissection added 2011, Thomas Buchanan <tom at thomasbuchanan dot com>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+/*
+ * See Mongo Wire Protocol Specification
+ * http://www.mongodb.org/display/DOCS/Mongo+Wire+Protocol
+ * See also BSON Specification
+ * http://bsonspec.org/#/specification
+ */
+
+#include "config.h"
+
+#include <epan/packet.h>
+#include <epan/exceptions.h>
+#include <epan/expert.h>
+#include <epan/proto_data.h>
+#include <wsutil/crc32.h> // CRC32C_PRELOAD
+#include <epan/crc32-tvb.h> // crc32c_tvb_offset_calculate
+#include "packet-tcp.h"
+#include "packet-tls.h"
+#ifdef HAVE_SNAPPY
+#include <snappy-c.h>
+#endif
+
+void proto_register_mongo(void);
+void proto_reg_handoff_mongo(void);
+
+static dissector_handle_t mongo_handle;
+
+/* Forward declaration */
+static int
+dissect_opcode_types(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *mongo_tree, guint opcode, guint *effective_opcode);
+
+/* This is not IANA assigned nor registered */
+#define TCP_PORT_MONGO 27017
+
+/* the code can reasonably attempt to decompress buffer up to 20MB */
+#define MAX_UNCOMPRESSED_SIZE (20 * 1024 * 1024)
+
+#define OP_REPLY           1
+#define OP_MESSAGE      1000
+#define OP_UPDATE       2001
+#define OP_INSERT       2002
+#define OP_RESERVED     2003
+#define OP_QUERY        2004
+#define OP_GET_MORE     2005
+#define OP_DELETE       2006
+#define OP_KILL_CURSORS 2007
+#define OP_COMMAND      2010
+#define OP_COMMANDREPLY 2011
+#define OP_COMPRESSED   2012
+#define OP_MSG          2013
+
+/**************************************************************************/
+/*                      OpCode                                            */
+/**************************************************************************/
+static const value_string opcode_vals[] = {
+  { OP_REPLY,  "Reply" },
+  { OP_MESSAGE, "Message" },
+  { OP_UPDATE,  "Update document" },
+  { OP_INSERT,  "Insert document" },
+  { OP_RESERVED,"Reserved" },
+  { OP_QUERY,  "Query" },
+  { OP_GET_MORE,  "Get More" },
+  { OP_DELETE,  "Delete document" },
+  { OP_KILL_CURSORS,  "Kill Cursors" },
+  { OP_COMMAND,  "Command Request" },
+  { OP_COMMANDREPLY,  "Command Reply" },
+  { OP_COMPRESSED,  "Compressed Data" },
+  { OP_MSG,  "Extensible Message Format" },
+  { 0,  NULL }
+};
+
+#define KIND_BODY               0
+#define KIND_DOCUMENT_SEQUENCE  1
+
+/**************************************************************************/
+/*                      Section Kind                                      */
+/**************************************************************************/
+static const value_string section_kind_vals[] = {
+  { KIND_BODY, "Body" },
+  { KIND_DOCUMENT_SEQUENCE, "Document Sequence" },
+  { 0,  NULL }
+};
+
+/**************************************************************************/
+/*                      Compression Engines                               */
+/**************************************************************************/
+#define MONGO_COMPRESSOR_NOOP    0
+#define MONGO_COMPRESSOR_SNAPPY  1
+#define MONGO_COMPRESSOR_ZLIB    2
+#define MONGO_COMPRESSOR_ZSTD    3
+
+static const value_string compressor_vals[] = {
+  { MONGO_COMPRESSOR_NOOP,   "Noop (Uncompressed)" },
+  { MONGO_COMPRESSOR_SNAPPY, "Snappy" },
+  { MONGO_COMPRESSOR_ZLIB,   "Zlib" },
+  { MONGO_COMPRESSOR_ZSTD,   "Zstd" },
+  { 0,  NULL }
+};
+
+/* BSON Element types */
+/* See http://bsonspec.org/#/specification for detail */
+#define BSON_ELEMENT_TYPE_DOUBLE         1
+#define BSON_ELEMENT_TYPE_STRING         2
+#define BSON_ELEMENT_TYPE_DOC            3
+#define BSON_ELEMENT_TYPE_ARRAY          4
+#define BSON_ELEMENT_TYPE_BINARY         5
+#define BSON_ELEMENT_TYPE_UNDEF          6  /* Deprecated */
+#define BSON_ELEMENT_TYPE_OBJ_ID         7
+#define BSON_ELEMENT_TYPE_BOOL           8
+#define BSON_ELEMENT_TYPE_DATETIME       9
+#define BSON_ELEMENT_TYPE_NULL          10
+#define BSON_ELEMENT_TYPE_REGEX         11
+#define BSON_ELEMENT_TYPE_DB_PTR        12  /* Deprecated */
+#define BSON_ELEMENT_TYPE_JS_CODE       13
+#define BSON_ELEMENT_TYPE_SYMBOL        14
+#define BSON_ELEMENT_TYPE_JS_CODE_SCOPE 15
+#define BSON_ELEMENT_TYPE_INT32         16  /* 0x10 */
+#define BSON_ELEMENT_TYPE_TIMESTAMP     17  /* 0x11 */
+#define BSON_ELEMENT_TYPE_INT64         18  /* 0x12 */
+#define BSON_ELEMENT_TYPE_DECIMAL128    19  /* 0x13 */
+#define BSON_ELEMENT_TYPE_MIN_KEY      255  /* 0xFF */
+#define BSON_ELEMENT_TYPE_MAX_KEY      127  /* 0x7F */
+
+static const value_string element_type_vals[] = {
+  { BSON_ELEMENT_TYPE_DOUBLE,         "Double" },
+  { BSON_ELEMENT_TYPE_STRING,         "String" },
+  { BSON_ELEMENT_TYPE_DOC,            "Document" },
+  { BSON_ELEMENT_TYPE_ARRAY,          "Array" },
+  { BSON_ELEMENT_TYPE_BINARY,         "Binary" },
+  { BSON_ELEMENT_TYPE_UNDEF,          "Undefined" },
+  { BSON_ELEMENT_TYPE_OBJ_ID,         "Object ID" },
+  { BSON_ELEMENT_TYPE_BOOL,           "Boolean" },
+  { BSON_ELEMENT_TYPE_DATETIME,       "Datetime" },
+  { BSON_ELEMENT_TYPE_NULL,           "NULL" },
+  { BSON_ELEMENT_TYPE_REGEX,          "Regular Expression" },
+  { BSON_ELEMENT_TYPE_DB_PTR,         "DBPointer" },
+  { BSON_ELEMENT_TYPE_JS_CODE,        "JavaScript Code" },
+  { BSON_ELEMENT_TYPE_SYMBOL,         "Symbol" },
+  { BSON_ELEMENT_TYPE_JS_CODE_SCOPE,  "JavaScript Code w/Scope" },
+  { BSON_ELEMENT_TYPE_INT32,          "Int32" },
+  { BSON_ELEMENT_TYPE_TIMESTAMP,      "Timestamp" },
+  { BSON_ELEMENT_TYPE_INT64,          "Int64" },
+  { BSON_ELEMENT_TYPE_DECIMAL128,     "128-bit decimal floating point" },
+  { BSON_ELEMENT_TYPE_MIN_KEY,        "Min Key" },
+  { BSON_ELEMENT_TYPE_MAX_KEY,        "Max Key" },
+  { 0, NULL }
+};
+
+/* BSON Element Binary subtypes */
+#define BSON_ELEMENT_BINARY_TYPE_GENERIC  0
+#define BSON_ELEMENT_BINARY_TYPE_FUNCTION 1
+#define BSON_ELEMENT_BINARY_TYPE_BINARY   2 /* OLD */
+#define BSON_ELEMENT_BINARY_TYPE_UUID     3
+#define BSON_ELEMENT_BINARY_TYPE_MD5      4
+#define BSON_ELEMENT_BINARY_TYPE_USER   128 /* 0x80 */
+
+#if 0
+static const value_string binary_type_vals[] = {
+  { BSON_ELEMENT_BINARY_TYPE_GENERIC,  "Generic" },
+  { BSON_ELEMENT_BINARY_TYPE_FUNCTION, "Function" },
+  { BSON_ELEMENT_BINARY_TYPE_BINARY,   "Binary" },
+  { BSON_ELEMENT_BINARY_TYPE_UUID,     "UUID" },
+  { BSON_ELEMENT_BINARY_TYPE_MD5,      "MD5" },
+  { BSON_ELEMENT_BINARY_TYPE_USER,     "User" },
+  { 0, NULL }
+};
+#endif
+
+static int proto_mongo = -1;
+static int hf_mongo_message_length = -1;
+static int hf_mongo_request_id = -1;
+static int hf_mongo_response_to = -1;
+static int hf_mongo_op_code = -1;
+static int hf_mongo_fullcollectionname = -1;
+static int hf_mongo_database_name = -1;
+static int hf_mongo_collection_name = -1;
+static int hf_mongo_reply_flags = -1;
+static int hf_mongo_reply_flags_cursornotfound = -1;
+static int hf_mongo_reply_flags_queryfailure = -1;
+static int hf_mongo_reply_flags_sharedconfigstale = -1;
+static int hf_mongo_reply_flags_awaitcapable = -1;
+static int hf_mongo_cursor_id = -1;
+static int hf_mongo_starting_from = -1;
+static int hf_mongo_number_returned = -1;
+static int hf_mongo_message = -1;
+static int hf_mongo_zero = -1;
+static int hf_mongo_update_flags = -1;
+static int hf_mongo_update_flags_upsert = -1;
+static int hf_mongo_update_flags_multiupdate = -1;
+static int hf_mongo_selector = -1;
+static int hf_mongo_update = -1;
+static int hf_mongo_insert_flags = -1;
+static int hf_mongo_insert_flags_continueonerror = -1;
+static int hf_mongo_query_flags = -1;
+static int hf_mongo_query_flags_tailablecursor = -1;
+static int hf_mongo_query_flags_slaveok = -1;
+static int hf_mongo_query_flags_oplogreplay = -1;
+static int hf_mongo_query_flags_nocursortimeout = -1;
+static int hf_mongo_query_flags_awaitdata = -1;
+static int hf_mongo_query_flags_exhaust = -1;
+static int hf_mongo_query_flags_partial = -1;
+static int hf_mongo_number_to_skip = -1;
+static int hf_mongo_number_to_return = -1;
+static int hf_mongo_query = -1;
+static int hf_mongo_return_field_selector = -1;
+static int hf_mongo_document = -1;
+static int hf_mongo_document_length = -1;
+static int hf_mongo_document_empty = -1;
+static int hf_mongo_delete_flags = -1;
+static int hf_mongo_delete_flags_singleremove = -1;
+static int hf_mongo_number_of_cursor_ids = -1;
+static int hf_mongo_elements = -1;
+static int hf_mongo_element_name = -1;
+static int hf_mongo_element_type = -1;
+static int hf_mongo_element_length = -1;
+static int hf_mongo_element_value_boolean = -1;
+static int hf_mongo_element_value_int32 = -1;
+static int hf_mongo_element_value_int64 = -1;
+static int hf_mongo_element_value_decimal128 = -1;
+static int hf_mongo_element_value_double = -1;
+static int hf_mongo_element_value_string = -1;
+static int hf_mongo_element_value_string_length = -1;
+static int hf_mongo_element_value_binary = -1;
+static int hf_mongo_element_value_binary_length = -1;
+static int hf_mongo_element_value_regex_pattern = -1;
+static int hf_mongo_element_value_regex_options = -1;
+static int hf_mongo_element_value_objectid = -1;
+static int hf_mongo_element_value_objectid_time = -1;
+static int hf_mongo_element_value_objectid_host = -1;
+static int hf_mongo_element_value_objectid_pid = -1;
+static int hf_mongo_element_value_objectid_machine_id = -1;
+static int hf_mongo_element_value_objectid_inc = -1;
+static int hf_mongo_element_value_db_ptr = -1;
+static int hf_mongo_element_value_js_code = -1;
+static int hf_mongo_element_value_js_scope = -1;
+static int hf_mongo_database = -1;
+static int hf_mongo_commandname = -1;
+static int hf_mongo_metadata = -1;
+static int hf_mongo_commandargs = -1;
+static int hf_mongo_commandreply = -1;
+static int hf_mongo_outputdocs = -1;
+static int hf_mongo_unknown = -1;
+static int hf_mongo_compression_info = -1;
+static int hf_mongo_original_op_code = -1;
+static int hf_mongo_uncompressed_size = -1;
+static int hf_mongo_compressor = -1;
+static int hf_mongo_compressed_data = -1;
+static int hf_mongo_unsupported_compressed = -1;
+static int hf_mongo_msg_flags = -1;
+static int hf_mongo_msg_flags_checksumpresent = -1;
+static int hf_mongo_msg_flags_moretocome = -1;
+static int hf_mongo_msg_flags_exhaustallowed = -1;
+static int hf_mongo_msg_sections_section = -1;
+static int hf_mongo_msg_sections_section_kind = -1;
+static int hf_mongo_msg_sections_section_body = -1;
+static int hf_mongo_msg_sections_section_doc_sequence = -1;
+static int hf_mongo_msg_sections_section_size = -1;
+static int hf_mongo_msg_sections_section_doc_sequence_id = -1;
+static int hf_mongo_msg_checksum = -1;
+static int hf_mongo_msg_checksum_status = -1;
+
+static gint ett_mongo = -1;
+static gint ett_mongo_doc = -1;
+static gint ett_mongo_elements = -1;
+static gint ett_mongo_element = -1;
+static gint ett_mongo_objectid = -1;
+static gint ett_mongo_machine_id = -1;
+static gint ett_mongo_code = -1;
+static gint ett_mongo_fcn = -1;
+static gint ett_mongo_flags = -1;
+static gint ett_mongo_compression_info = -1;
+static gint ett_mongo_sections = -1;
+static gint ett_mongo_section = -1;
+static gint ett_mongo_msg_flags = -1;
+static gint ett_mongo_doc_sequence= -1;
+
+static expert_field ei_mongo_document_recursion_exceeded = EI_INIT;
+static expert_field ei_mongo_document_length_bad = EI_INIT;
+static expert_field ei_mongo_unknown = EI_INIT;
+static expert_field ei_mongo_unsupported_compression = EI_INIT;
+static expert_field ei_mongo_too_large_compressed = EI_INIT;
+static expert_field ei_mongo_msg_checksum = EI_INIT;
+
+static int
+dissect_fullcollectionname(tvbuff_t *tvb, guint offset, proto_tree *tree)
+{
+  gint32 fcn_length, dbn_length;
+  proto_item *ti;
+  proto_tree *fcn_tree;
+
+  fcn_length = tvb_strsize(tvb, offset);
+  ti = proto_tree_add_item(tree, hf_mongo_fullcollectionname, tvb, offset, fcn_length, ENC_ASCII);
+
+  /* If this doesn't find anything, we'll just throw an exception below */
+  dbn_length = tvb_find_guint8(tvb, offset, fcn_length, '.') - offset;
+
+  fcn_tree = proto_item_add_subtree(ti, ett_mongo_fcn);
+
+  proto_tree_add_item(fcn_tree, hf_mongo_database_name, tvb, offset, dbn_length, ENC_ASCII);
+
+  proto_tree_add_item(fcn_tree, hf_mongo_collection_name, tvb, offset + 1 + dbn_length, fcn_length - dbn_length - 2, ENC_ASCII);
+
+  return fcn_length;
+}
+
+/* http://docs.mongodb.org/manual/reference/limits/ */
+/* http://www.mongodb.org/display/DOCS/Documents */
+#define BSON_MAX_NESTING 100
+#define BSON_MAX_DOC_SIZE (16 * 1000 * 1000)
+static int
+dissect_bson_document(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree, int hf_mongo_doc)
+{
+  gint32 document_length;
+  guint final_offset;
+  proto_item *ti, *elements, *element, *objectid, *js_code, *js_scope, *machine_id;
+  proto_tree *doc_tree, *elements_tree, *element_sub_tree, *objectid_sub_tree, *js_code_sub_tree, *js_scope_sub_tree, *machine_id_sub_tree;
+
+  document_length = tvb_get_letohl(tvb, offset);
+
+  ti = proto_tree_add_item(tree, hf_mongo_doc, tvb, offset, document_length, ENC_NA);
+  doc_tree = proto_item_add_subtree(ti, ett_mongo_doc);
+
+  proto_tree_add_item(doc_tree, hf_mongo_document_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+
+  if (document_length < 5) {
+      expert_add_info_format(pinfo, ti, &ei_mongo_document_length_bad, "BSON document length too short: %u", document_length);
+      return MAX(4, document_length); /* see the comment above */
+  }
+
+  if (document_length > BSON_MAX_DOC_SIZE) {
+      expert_add_info_format(pinfo, ti, &ei_mongo_document_length_bad, "BSON document length too long: %u", document_length);
+      return document_length;
+  }
+
+  if (document_length == 5) {
+    /* document with length 5 is an empty document */
+    /* don't display the element subtree */
+    proto_tree_add_item(doc_tree, hf_mongo_document_empty, tvb, offset, document_length, ENC_NA);
+    return document_length;
+  }
+
+  unsigned nest_level = p_get_proto_depth(pinfo, proto_mongo);
+  if (++nest_level > BSON_MAX_NESTING) {
+      expert_add_info_format(pinfo, ti, &ei_mongo_document_recursion_exceeded, "BSON document recursion exceeds %u", BSON_MAX_NESTING);
+      /* return the number of bytes we consumed, these are at least the 4 bytes for the length field */
+      return MAX(4, document_length);
+  }
+  p_set_proto_depth(pinfo, proto_mongo, nest_level);
+
+  final_offset = offset + document_length;
+  offset += 4;
+
+  elements = proto_tree_add_item(doc_tree, hf_mongo_elements, tvb, offset, document_length-5, ENC_NA);
+  elements_tree = proto_item_add_subtree(elements, ett_mongo_elements);
+
+  do {
+    /* Read document elements */
+    guint8 e_type;  /* Element type */
+    gint str_len = -1;   /* String length */
+    gint e_len = -1;     /* Element length */
+    gint doc_len = -1;   /* Document length */
+
+    e_type = tvb_get_guint8(tvb, offset);
+    tvb_get_stringz_enc(pinfo->pool, tvb, offset+1, &str_len, ENC_ASCII);
+
+    element = proto_tree_add_item(elements_tree, hf_mongo_element_name, tvb, offset+1, str_len-1, ENC_UTF_8);
+    element_sub_tree = proto_item_add_subtree(element, ett_mongo_element);
+    proto_tree_add_item(element_sub_tree, hf_mongo_element_type, tvb, offset, 1, ENC_LITTLE_ENDIAN);
+
+    offset += str_len+1;
+
+    switch(e_type) {
+      case BSON_ELEMENT_TYPE_DOUBLE:
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_double, tvb, offset, 8, ENC_LITTLE_ENDIAN);
+        offset += 8;
+        break;
+      case BSON_ELEMENT_TYPE_STRING:
+      case BSON_ELEMENT_TYPE_JS_CODE:
+      case BSON_ELEMENT_TYPE_SYMBOL:
+        str_len = tvb_get_letohl(tvb, offset);
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_string_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_string, tvb, offset+4, str_len, ENC_UTF_8);
+        offset += str_len+4;
+        break;
+      case BSON_ELEMENT_TYPE_DOC:
+      case BSON_ELEMENT_TYPE_ARRAY:
+        offset += dissect_bson_document(tvb, pinfo, offset, element_sub_tree, hf_mongo_document);
+        break;
+      case BSON_ELEMENT_TYPE_BINARY:
+        e_len = tvb_get_letohl(tvb, offset);
+        /* TODO - Add functions to decode various binary subtypes */
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_binary_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_binary, tvb, offset+5, e_len, ENC_NA);
+        offset += e_len+5;
+        break;
+      case BSON_ELEMENT_TYPE_UNDEF:
+      case BSON_ELEMENT_TYPE_NULL:
+      case BSON_ELEMENT_TYPE_MIN_KEY:
+      case BSON_ELEMENT_TYPE_MAX_KEY:
+        /* Nothing to do, as there is no element content */
+        break;
+      case BSON_ELEMENT_TYPE_OBJ_ID:
+        objectid = proto_tree_add_item(element_sub_tree, hf_mongo_element_value_objectid, tvb, offset, 12, ENC_NA);
+        objectid_sub_tree = proto_item_add_subtree(objectid, ett_mongo_objectid);
+        /* Unlike most BSON elements, parts of ObjectID are stored Big Endian, so they can be compared bit by bit */
+        proto_tree_add_item(objectid_sub_tree, hf_mongo_element_value_objectid_time, tvb, offset, 4, ENC_BIG_ENDIAN);
+        /* The machine ID was traditionally split up in Host Hash/PID */
+        machine_id = proto_tree_add_item(objectid_sub_tree, hf_mongo_element_value_objectid_machine_id, tvb, offset+4, 5, ENC_NA);
+        machine_id_sub_tree = proto_item_add_subtree(machine_id, ett_mongo_machine_id);
+        proto_tree_add_item(machine_id_sub_tree, hf_mongo_element_value_objectid_host, tvb, offset+4, 3, ENC_LITTLE_ENDIAN);
+        proto_tree_add_item(machine_id_sub_tree, hf_mongo_element_value_objectid_pid, tvb, offset+7, 2, ENC_LITTLE_ENDIAN);
+
+        proto_tree_add_item(objectid_sub_tree, hf_mongo_element_value_objectid_inc, tvb, offset+9, 3, ENC_BIG_ENDIAN);
+        offset += 12;
+        break;
+      case BSON_ELEMENT_TYPE_BOOL:
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_boolean, tvb, offset, 1, ENC_NA);
+        offset += 1;
+        break;
+      case BSON_ELEMENT_TYPE_REGEX:
+        /* regex pattern */
+        tvb_get_stringz_enc(pinfo->pool, tvb, offset, &str_len, ENC_ASCII);
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_regex_pattern, tvb, offset, str_len, ENC_UTF_8);
+        offset += str_len;
+        /* regex options */
+        tvb_get_stringz_enc(pinfo->pool, tvb, offset, &str_len, ENC_ASCII);
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_regex_options, tvb, offset, str_len, ENC_UTF_8);
+        offset += str_len;
+        break;
+      case BSON_ELEMENT_TYPE_DB_PTR:
+        str_len = tvb_get_letohl(tvb, offset);
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_string_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_string, tvb, offset+4, str_len, ENC_UTF_8);
+        offset += str_len;
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_db_ptr, tvb, offset, 12, ENC_NA);
+        offset += 12;
+        break;
+      case BSON_ELEMENT_TYPE_JS_CODE_SCOPE:
+        /* code_w_s ::= int32 string document */
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+        e_len = tvb_get_letohl(tvb, offset);
+        offset += 4;
+        str_len = tvb_get_letohl(tvb, offset);
+        js_code = proto_tree_add_item(element_sub_tree, hf_mongo_element_value_js_code, tvb, offset, str_len+4, ENC_NA);
+        js_code_sub_tree = proto_item_add_subtree(js_code, ett_mongo_code);
+        proto_tree_add_item(js_code_sub_tree, hf_mongo_element_value_string_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+        proto_tree_add_item(js_code_sub_tree, hf_mongo_element_value_string, tvb, offset+4, str_len, ENC_UTF_8);
+        offset += str_len+4;
+        doc_len = e_len - (str_len + 8);
+        js_scope = proto_tree_add_item(element_sub_tree, hf_mongo_element_value_js_scope, tvb, offset, doc_len, ENC_NA);
+        js_scope_sub_tree = proto_item_add_subtree(js_scope, ett_mongo_code);
+        offset += dissect_bson_document(tvb, pinfo, offset, js_scope_sub_tree, hf_mongo_document);
+        break;
+      case BSON_ELEMENT_TYPE_INT32:
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_int32, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+        offset += 4;
+        break;
+      case BSON_ELEMENT_TYPE_DATETIME:
+      case BSON_ELEMENT_TYPE_TIMESTAMP:
+        /* TODO Implement routine to convert datetime & timestamp values to UTC date/time */
+        /* for now, simply display the integer value */
+      case BSON_ELEMENT_TYPE_INT64:
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_int64, tvb, offset, 8, ENC_LITTLE_ENDIAN);
+        offset += 8;
+        break;
+      case BSON_ELEMENT_TYPE_DECIMAL128:
+        /* TODO Implement routine to convert to decimal128 for now, simply display bytes */
+        /* https://github.com/mongodb/specifications/blob/master/source/bson-decimal128/decimal128.rst */
+        proto_tree_add_item(element_sub_tree, hf_mongo_element_value_decimal128, tvb, offset, 16, ENC_NA);
+        offset += 16;
+        break;
+      default:
+        break;
+    }  /* end switch() */
+  } while (offset < final_offset-1);
+
+  // Restore depth.
+  nest_level--;
+  p_set_proto_depth(pinfo, proto_mongo, nest_level);
+
+  return document_length;
+}
+
+static int
+dissect_mongo_reply(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree)
+{
+  proto_item *ti;
+  proto_tree *flags_tree;
+  gint i, number_returned;
+
+  ti = proto_tree_add_item(tree, hf_mongo_reply_flags, tvb, offset, 4, ENC_NA);
+  flags_tree = proto_item_add_subtree(ti, ett_mongo_flags);
+  proto_tree_add_item(flags_tree, hf_mongo_reply_flags_cursornotfound, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_reply_flags_queryfailure, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_reply_flags_sharedconfigstale, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_reply_flags_awaitcapable, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset += 4;
+
+  proto_tree_add_item(tree, hf_mongo_cursor_id, tvb, offset, 8, ENC_LITTLE_ENDIAN);
+  offset += 8;
+
+  proto_tree_add_item(tree, hf_mongo_starting_from, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset += 4;
+
+  proto_tree_add_item(tree, hf_mongo_number_returned, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  number_returned = tvb_get_letohl(tvb, offset);
+  offset += 4;
+
+  for (i=0; i < number_returned; i++)
+  {
+    offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_document);
+  }
+  return offset;
+}
+
+static int
+dissect_mongo_msg(tvbuff_t *tvb, guint offset, proto_tree *tree)
+{
+  proto_tree_add_item(tree, hf_mongo_message, tvb, offset, -1, ENC_ASCII);
+  offset += tvb_strsize(tvb, offset);
+
+  return offset;
+}
+
+static int
+dissect_mongo_update(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree)
+{
+  proto_item *ti;
+  proto_tree *flags_tree;
+
+  proto_tree_add_item(tree, hf_mongo_zero, tvb, offset, 4, ENC_NA);
+  offset += 4;
+
+  offset += dissect_fullcollectionname(tvb, offset, tree);
+
+  ti = proto_tree_add_item(tree, hf_mongo_update_flags, tvb, offset, 4, ENC_NA);
+  flags_tree = proto_item_add_subtree(ti, ett_mongo_flags);
+  proto_tree_add_item(flags_tree, hf_mongo_update_flags_upsert, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_update_flags_multiupdate, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset += 4;
+
+  offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_selector);
+
+  offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_update);
+
+  return offset;
+}
+
+static int
+dissect_mongo_insert(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree)
+{
+  proto_item *ti;
+  proto_tree *flags_tree;
+
+  ti = proto_tree_add_item(tree, hf_mongo_insert_flags, tvb, offset, 4, ENC_NA);
+  flags_tree = proto_item_add_subtree(ti, ett_mongo_flags);
+  proto_tree_add_item(flags_tree, hf_mongo_insert_flags_continueonerror, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset += 4;
+
+  offset += dissect_fullcollectionname(tvb, offset, tree);
+
+  while(offset < tvb_reported_length(tvb)) {
+    offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_document);
+  }
+
+  return offset;
+}
+
+static int
+dissect_mongo_query(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree)
+{
+  proto_item *ti;
+  proto_tree *flags_tree;
+
+  ti = proto_tree_add_item(tree, hf_mongo_query_flags, tvb, offset, 4, ENC_NA);
+  flags_tree = proto_item_add_subtree(ti, ett_mongo_flags);
+  proto_tree_add_item(flags_tree, hf_mongo_query_flags_tailablecursor, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_query_flags_slaveok, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_query_flags_oplogreplay, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_query_flags_nocursortimeout, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_query_flags_awaitdata, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_query_flags_exhaust, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(flags_tree, hf_mongo_query_flags_partial, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset += 4;
+
+  offset += dissect_fullcollectionname(tvb, offset, tree);
+
+  proto_tree_add_item(tree, hf_mongo_number_to_skip, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset += 4;
+
+  proto_tree_add_item(tree, hf_mongo_number_to_return, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset +=4;
+
+  offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_query);
+
+  while(offset < tvb_reported_length(tvb)) {
+    offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_return_field_selector);
+  }
+  return offset;
+}
+
+static int
+dissect_mongo_getmore(tvbuff_t *tvb, guint offset, proto_tree *tree)
+{
+
+  proto_tree_add_item(tree, hf_mongo_zero, tvb, offset, 4, ENC_NA);
+  offset += 4;
+
+  offset += dissect_fullcollectionname(tvb, offset, tree);
+
+  proto_tree_add_item(tree, hf_mongo_number_to_return, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset += 4;
+
+  proto_tree_add_item(tree, hf_mongo_cursor_id, tvb, offset, 8, ENC_LITTLE_ENDIAN);
+  offset += 8;
+
+  return offset;
+}
+
+static int
+dissect_mongo_delete(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree)
+{
+  proto_item *ti;
+  proto_tree *flags_tree;
+
+  proto_tree_add_item(tree, hf_mongo_zero, tvb, offset, 4, ENC_NA);
+  offset += 4;
+
+  offset += dissect_fullcollectionname(tvb, offset, tree);
+
+  ti = proto_tree_add_item(tree, hf_mongo_delete_flags, tvb, offset, 4, ENC_NA);
+  flags_tree = proto_item_add_subtree(ti, ett_mongo_flags);
+  proto_tree_add_item(flags_tree, hf_mongo_delete_flags_singleremove, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset += 4;
+
+  offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_selector);
+
+  return offset;
+}
+
+static int
+dissect_mongo_kill_cursors(tvbuff_t *tvb, guint offset, proto_tree *tree)
+{
+
+  proto_tree_add_item(tree, hf_mongo_zero, tvb, offset, 4, ENC_NA);
+  offset += 4;
+
+  proto_tree_add_item(tree, hf_mongo_number_of_cursor_ids, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  offset += 4;
+
+  while(offset < tvb_reported_length(tvb)) {
+    proto_tree_add_item(tree, hf_mongo_cursor_id, tvb, offset, 8, ENC_LITTLE_ENDIAN);
+    offset +=8;
+  }
+  return offset;
+}
+
+static int
+dissect_mongo_op_command(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree)
+{
+  gint32 db_length, cmd_length;
+
+  db_length = tvb_strsize(tvb, offset);
+  proto_tree_add_item(tree, hf_mongo_database, tvb, offset, db_length, ENC_ASCII);
+  offset += db_length;
+
+  cmd_length = tvb_strsize(tvb, offset);
+  proto_tree_add_item(tree, hf_mongo_commandname, tvb, offset, cmd_length, ENC_ASCII);
+  offset += cmd_length;
+
+  offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_metadata);
+
+  offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_commandargs);
+
+  return offset;
+}
+
+static int
+dissect_mongo_op_commandreply(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree)
+{
+
+  offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_metadata);
+
+  offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_commandreply);
+
+  if (tvb_reported_length_remaining(tvb, offset) > 0){
+    offset += dissect_bson_document(tvb, pinfo, offset, tree, hf_mongo_outputdocs);
+  }
+
+  return offset;
+}
+
+static int
+dissect_mongo_op_compressed(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree, guint *effective_opcode)
+{
+  guint opcode = 0;
+  guint8 compressor;
+  proto_item *ti;
+  proto_tree *compression_info_tree;
+
+  ti = proto_tree_add_item(tree, hf_mongo_compression_info, tvb, offset, 9, ENC_NA);
+  compression_info_tree = proto_item_add_subtree(ti, ett_mongo_compression_info);
+  proto_tree_add_item(compression_info_tree, hf_mongo_original_op_code, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(compression_info_tree, hf_mongo_uncompressed_size, tvb, offset + 4, 4, ENC_LITTLE_ENDIAN);
+  proto_tree_add_item(compression_info_tree, hf_mongo_compressor, tvb, offset + 8, 1, ENC_NA);
+  proto_tree_add_item(compression_info_tree, hf_mongo_compressed_data, tvb, offset + 9, -1, ENC_NA);
+
+  opcode = tvb_get_letohl(tvb, offset);
+  *effective_opcode = opcode;
+  compressor = tvb_get_guint8(tvb, offset + 8);
+  offset += 9;
+
+  switch(compressor) {
+  case MONGO_COMPRESSOR_NOOP:
+    offset = dissect_opcode_types(tvb, pinfo, offset, tree, opcode, effective_opcode);
+    break;
+
+#ifdef HAVE_SNAPPY
+  case MONGO_COMPRESSOR_SNAPPY: {
+    guchar *decompressed_buffer = NULL;
+    size_t orig_size = 0;
+    snappy_status ret;
+    tvbuff_t* compressed_tvb = NULL;
+
+    /* get the raw data length */
+    ret = snappy_uncompressed_length(tvb_get_ptr(tvb, offset, -1),
+      tvb_captured_length_remaining(tvb, offset),
+      &orig_size);
+    /* if we get the length and it's reasonably short to allocate a buffer for it
+     * proceed to try decompressing the data
+     */
+    if (ret == SNAPPY_OK && orig_size <= MAX_UNCOMPRESSED_SIZE) {
+      decompressed_buffer = (guchar*)wmem_alloc(pinfo->pool, orig_size);
+
+      ret = snappy_uncompress(tvb_get_ptr(tvb, offset, -1),
+        tvb_captured_length_remaining(tvb, offset),
+        decompressed_buffer,
+        &orig_size);
+
+      if (ret == SNAPPY_OK) {
+        compressed_tvb = tvb_new_child_real_data(tvb, decompressed_buffer, (guint32)orig_size, (guint32)orig_size);
+        add_new_data_source(pinfo, compressed_tvb, "Decompressed Data");
+
+        dissect_opcode_types(compressed_tvb, pinfo, 0, tree, opcode, effective_opcode);
+      } else {
+        expert_add_info_format(pinfo, ti, &ei_mongo_unsupported_compression, "Error uncompressing snappy data");
+      }
+    } else {
+      if (orig_size > MAX_UNCOMPRESSED_SIZE) {
+        expert_add_info_format(pinfo, ti, &ei_mongo_too_large_compressed, "Uncompressed size too large");
+      } else {
+        expert_add_info_format(pinfo, ti, &ei_mongo_unsupported_compression, "Error uncompressing snappy data");
+      }
+    }
+
+    offset = tvb_reported_length(tvb);
+  } break;
+#endif
+
+#ifdef HAVE_ZSTD
+  case MONGO_COMPRESSOR_ZSTD:
+  {
+    tvbuff_t *uncompressed_tvb = tvb_child_uncompress_zstd (tvb, tvb, offset, tvb_captured_length_remaining (tvb, offset));
+    if (!uncompressed_tvb) {
+      expert_add_info_format(pinfo, ti, &ei_mongo_unsupported_compression, "Error uncompressing zstd data");
+    } else {
+      add_new_data_source(pinfo, uncompressed_tvb, "Decompressed Data");
+      dissect_opcode_types(uncompressed_tvb, pinfo, 0, tree, opcode, effective_opcode);
+    }
+
+    offset = tvb_reported_length(tvb);
+  }
+  break;
+#endif
+
+  case MONGO_COMPRESSOR_ZLIB: {
+    tvbuff_t* compressed_tvb = NULL;
+
+    compressed_tvb = tvb_child_uncompress(tvb, tvb, offset, tvb_captured_length_remaining(tvb, offset));
+
+    if (compressed_tvb) {
+      add_new_data_source(pinfo, compressed_tvb, "Decompressed Data");
+
+      dissect_opcode_types(compressed_tvb, pinfo, 0, tree, opcode, effective_opcode);
+    } else {
+      proto_tree_add_item(compression_info_tree, hf_mongo_unsupported_compressed, tvb, offset, -1, ENC_NA);
+      expert_add_info_format(pinfo, ti, &ei_mongo_unsupported_compression, "Error uncompressing zlib data");
+    }
+
+    offset = tvb_reported_length(tvb);
+  } break;
+
+  default:
+    proto_tree_add_item(compression_info_tree, hf_mongo_unsupported_compressed, tvb, offset, -1, ENC_NA);
+    expert_add_info_format(pinfo, ti, &ei_mongo_unsupported_compression, "Unsupported compression format: %d", compressor);
+    offset = tvb_reported_length(tvb);
+    break;
+  }
+
+  return offset;
+}
+
+static int
+dissect_op_msg_section(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree)
+{
+  proto_item *ti;
+  proto_tree *section_tree;
+  guint8 e_type;
+  gint section_len = -1;   /* Section length */
+
+  e_type = tvb_get_guint8(tvb, offset);
+  section_len = tvb_get_letohl(tvb, offset+1);
+
+  ti = proto_tree_add_item(tree, hf_mongo_msg_sections_section, tvb, offset, 1 + section_len, ENC_NA);
+  section_tree = proto_item_add_subtree(ti, ett_mongo_section);
+  proto_tree_add_item(section_tree, hf_mongo_msg_sections_section_kind, tvb, offset, 1, ENC_LITTLE_ENDIAN);
+  offset += 1;
+
+  switch (e_type) {
+    case KIND_BODY:
+      dissect_bson_document(tvb, pinfo, offset, section_tree, hf_mongo_msg_sections_section_body);
+      break;
+    case KIND_DOCUMENT_SEQUENCE: {
+      gint32 dsi_length;
+      gint32 to_read = section_len;
+      proto_item *documents;
+      proto_tree *documents_tree;
+
+      proto_tree_add_item(section_tree, hf_mongo_msg_sections_section_size, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+      offset += 4;
+      to_read -= 4;
+
+      dsi_length = tvb_strsize(tvb, offset);
+      proto_tree_add_item(section_tree, hf_mongo_msg_sections_section_doc_sequence_id, tvb, offset, dsi_length, ENC_ASCII);
+      offset += dsi_length;
+      to_read -= dsi_length;
+
+      documents = proto_tree_add_item(section_tree, hf_mongo_msg_sections_section_doc_sequence, tvb, offset, to_read, ENC_NA);
+      documents_tree = proto_item_add_subtree(documents, ett_mongo_doc_sequence);
+
+      while (to_read > 0){
+        gint32 doc_size = dissect_bson_document(tvb, pinfo, offset, documents_tree, hf_mongo_document);
+        to_read -= doc_size;
+        offset += doc_size;
+      }
+
+    } break;
+    default:
+      expert_add_info_format(pinfo, tree, &ei_mongo_unknown, "Unknown section type: %u", e_type);
+  }
+
+  return 1 + section_len;
+}
+
+static int
+dissect_mongo_op_msg(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *tree)
+{
+  static int * const mongo_msg_flags[] = {
+    &hf_mongo_msg_flags_checksumpresent,
+    &hf_mongo_msg_flags_moretocome,
+    &hf_mongo_msg_flags_exhaustallowed,
+    NULL
+  };
+  gint64 op_msg_flags;
+  bool checksum_present = false;
+
+  proto_tree_add_bitmask_ret_uint64 (tree, tvb, offset, hf_mongo_msg_flags, ett_mongo_msg_flags, mongo_msg_flags, ENC_LITTLE_ENDIAN, &op_msg_flags);
+  if (op_msg_flags & 0x00000001) {
+    checksum_present = true;
+  }
+
+  offset += 4;
+
+  while (tvb_reported_length_remaining(tvb, offset) > (checksum_present ? 4 : 0)){
+    offset += dissect_op_msg_section(tvb, pinfo, offset, tree);
+  }
+
+  if (checksum_present) {
+    guint32 calculated_checksum = ~crc32c_tvb_offset_calculate (tvb, 0, tvb_reported_length (tvb) - 4, CRC32C_PRELOAD);
+    proto_tree_add_checksum(tree, tvb, offset, hf_mongo_msg_checksum, hf_mongo_msg_checksum_status, &ei_mongo_msg_checksum, pinfo, calculated_checksum, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
+    offset += 4;
+  }
+
+  return offset;
+}
+
+static int
+dissect_opcode_types(tvbuff_t *tvb, packet_info *pinfo, guint offset, proto_tree *mongo_tree, guint opcode, guint *effective_opcode)
+{
+    *effective_opcode = opcode;
+
+    switch(opcode){
+    case OP_REPLY:
+      offset = dissect_mongo_reply(tvb, pinfo, offset, mongo_tree);
+      break;
+    case OP_MESSAGE:
+      offset = dissect_mongo_msg(tvb, offset, mongo_tree);
+      break;
+    case OP_UPDATE:
+      offset = dissect_mongo_update(tvb, pinfo, offset, mongo_tree);
+      break;
+    case OP_INSERT:
+      offset = dissect_mongo_insert(tvb, pinfo, offset, mongo_tree);
+      break;
+    case OP_QUERY:
+      offset = dissect_mongo_query(tvb, pinfo, offset, mongo_tree);
+      break;
+    case OP_GET_MORE:
+      offset = dissect_mongo_getmore(tvb, offset, mongo_tree);
+      break;
+    case OP_DELETE:
+      offset = dissect_mongo_delete(tvb, pinfo, offset, mongo_tree);
+      break;
+    case OP_KILL_CURSORS:
+      offset = dissect_mongo_kill_cursors(tvb, offset, mongo_tree);
+      break;
+    case OP_COMMAND:
+      offset = dissect_mongo_op_command(tvb, pinfo, offset, mongo_tree);
+      break;
+    case OP_COMMANDREPLY:
+      offset = dissect_mongo_op_commandreply(tvb, pinfo, offset, mongo_tree);
+      break;
+    case OP_COMPRESSED:
+      offset = dissect_mongo_op_compressed(tvb, pinfo, offset, mongo_tree, effective_opcode);
+      break;
+    case OP_MSG:
+      offset = dissect_mongo_op_msg(tvb, pinfo, offset, mongo_tree);
+      break;
+    default:
+      /* No default Action */
+      break;
+    }
+
+    return offset;
+}
+
+static int
+dissect_mongo_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
+{
+    proto_item *ti;
+    proto_tree *mongo_tree;
+    guint offset = 0, opcode, effective_opcode = 0;
+
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "MONGO");
+
+    ti = proto_tree_add_item(tree, proto_mongo, tvb, 0, -1, ENC_NA);
+
+    mongo_tree = proto_item_add_subtree(ti, ett_mongo);
+
+    proto_tree_add_item(mongo_tree, hf_mongo_message_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+    offset += 4;
+
+    proto_tree_add_item(mongo_tree, hf_mongo_request_id, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+    offset += 4;
+
+    proto_tree_add_item(mongo_tree, hf_mongo_response_to, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+    offset += 4;
+
+    proto_tree_add_item(mongo_tree, hf_mongo_op_code, tvb, offset, 4, ENC_LITTLE_ENDIAN);
+    opcode = tvb_get_letohl(tvb, offset);
+    offset += 4;
+
+    offset = dissect_opcode_types(tvb, pinfo, offset, mongo_tree, opcode, &effective_opcode);
+
+    if(opcode == 1)
+    {
+      col_set_str(pinfo->cinfo, COL_INFO, "Response :");
+    }
+    else
+    {
+      col_set_str(pinfo->cinfo, COL_INFO, "Request :");
+
+    }
+    col_append_fstr(pinfo->cinfo, COL_INFO, " %s", val_to_str_const(effective_opcode, opcode_vals, "Unknown"));
+
+    if(opcode != effective_opcode) {
+      col_append_fstr(pinfo->cinfo, COL_INFO, " (Compressed)");
+    }
+
+    if(offset < tvb_reported_length(tvb))
+    {
+      ti = proto_tree_add_item(mongo_tree, hf_mongo_unknown, tvb, offset, -1, ENC_NA);
+      expert_add_info(pinfo, ti, &ei_mongo_unknown);
+    }
+
+    return tvb_captured_length(tvb);
+}
+static guint
+get_mongo_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
+{
+  guint32 plen;
+
+  /*
+  * Get the length of the MONGO packet.
+  */
+  plen = tvb_get_letohl(tvb, offset);
+
+  return plen;
+}
+
+static int
+dissect_mongo(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
+{
+  tcp_dissect_pdus(tvb, pinfo, tree, 1, 4, get_mongo_pdu_len, dissect_mongo_pdu, data);
+  return tvb_captured_length(tvb);
+}
+
+void
+proto_register_mongo(void)
+{
+  expert_module_t* expert_mongo;
+
+  static hf_register_info hf[] = {
+    { &hf_mongo_message_length,
+      { "Message Length", "mongo.message_length",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Total message size (include this)", HFILL }
+    },
+    { &hf_mongo_request_id,
+      { "Request ID", "mongo.request_id",
+      FT_UINT32, BASE_HEX_DEC, NULL, 0x0,
+      "Identifier for this message", HFILL }
+    },
+    { &hf_mongo_response_to,
+      { "Response To", "mongo.response_to",
+      FT_UINT32, BASE_HEX_DEC, NULL, 0x0,
+      "RequestID from the original request", HFILL }
+    },
+    { &hf_mongo_op_code,
+      { "OpCode", "mongo.opcode",
+      FT_INT32, BASE_DEC, VALS(opcode_vals), 0x0,
+      "Type of request message", HFILL }
+    },
+    { &hf_mongo_query_flags,
+      { "Query Flags", "mongo.query.flags",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Bit vector of query options.", HFILL }
+    },
+    { &hf_mongo_fullcollectionname,
+      { "fullCollectionName", "mongo.full_collection_name",
+      FT_STRINGZ, BASE_NONE, NULL, 0x0,
+      "The full collection name is the concatenation of the database name with the"
+        " collection name, using a dot for the concatenation", HFILL }
+    },
+    { &hf_mongo_database_name,
+      { "Database Name", "mongo.database_name",
+      FT_STRING, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_collection_name,
+      { "Collection Name", "mongo.collection_name",
+      FT_STRING, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_reply_flags,
+      { "Reply Flags", "mongo.reply.flags",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Bit vector of reply options.", HFILL }
+    },
+    { &hf_mongo_reply_flags_cursornotfound,
+      { "Cursor Not Found", "mongo.reply.flags.cursornotfound",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000001,
+      "Set when getMore is called but the cursor id is not valid at the server", HFILL }
+    },
+    { &hf_mongo_reply_flags_queryfailure,
+      { "Query Failure", "mongo.reply.flags.queryfailure",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000002,
+      "Set when query failed. Results consist of one document containing an $err"
+        " field describing the failure.", HFILL }
+    },
+    { &hf_mongo_reply_flags_sharedconfigstale,
+      { "Shared Config Stale", "mongo.reply.flags.sharedconfigstale",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000004,
+      NULL, HFILL }
+    },
+    { &hf_mongo_reply_flags_awaitcapable,
+      { "Await Capable", "mongo.reply.flags.awaitcapable",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000008,
+      "Set when the server supports the AwaitData Query option", HFILL }
+    },
+    { &hf_mongo_message,
+      { "Message", "mongo.message",
+      FT_STRINGZ, BASE_NONE, NULL, 0x0,
+      "Message for the database", HFILL }
+    },
+    { &hf_mongo_cursor_id,
+      { "Cursor ID", "mongo.cursor_id",
+      FT_INT64, BASE_DEC, NULL, 0x0,
+      "Cursor id if client needs to do get more's", HFILL }
+    },
+    { &hf_mongo_starting_from,
+      { "Starting From", "mongo.starting_from",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Where in the cursor this reply is starting", HFILL }
+    },
+    { &hf_mongo_number_returned,
+      { "Number Returned", "mongo.number_returned",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Number of documents in the reply", HFILL }
+    },
+    { &hf_mongo_document,
+      { "Document", "mongo.document",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_document_length,
+      { "Document length", "mongo.document.length",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Length of BSON Document", HFILL }
+    },
+    { &hf_mongo_document_empty,
+      { "Empty Document", "mongo.document.empty",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Document with no elements", HFILL }
+    },
+    { &hf_mongo_zero,
+      { "Zero", "mongo.document.zero",
+      FT_BYTES, BASE_NONE, NULL, 0x0,
+      "Reserved (Must be is Zero)", HFILL }
+    },
+    { &hf_mongo_update_flags,
+      { "Update Flags", "mongo.update.flags",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Bit vector of update options.", HFILL }
+    },
+    { &hf_mongo_update_flags_upsert,
+      { "Upsert", "mongo.update.flags.upsert",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000001,
+      "If set, the database will insert the supplied object into the collection if no"
+        " matching document is found", HFILL }
+    },
+    { &hf_mongo_update_flags_multiupdate,
+      { "Multi Update", "mongo.update.flags.multiupdate",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000002,
+      "If set, the database will update all matching objects in the collection."
+        " Otherwise only updates first matching doc.", HFILL }
+    },
+    { &hf_mongo_selector,
+      { "Selector", "mongo.selector",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "The query to select the document", HFILL }
+    },
+    { &hf_mongo_update,
+      { "Update", "mongo.update",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Specification of the update to perform", HFILL }
+    },
+    { &hf_mongo_insert_flags,
+      { "Insert Flags", "mongo.insert.flags",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Bit vector of insert options.", HFILL }
+    },
+    { &hf_mongo_insert_flags_continueonerror,
+      { "ContinueOnError", "mongo.insert.flags.continueonerror",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000001,
+      "If set, the database will not stop processing a bulk insert if one fails"
+        " (eg due to duplicate IDs)", HFILL }
+    },
+    { &hf_mongo_query_flags_tailablecursor,
+      { "Tailable Cursor", "mongo.query.flags.tailable_cursor",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000002,
+      "Tailable means cursor is not closed when the last data is retrieved", HFILL }
+    },
+    { &hf_mongo_query_flags_slaveok,
+      { "Slave OK", "mongo.query.flags.slave_ok",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000004,
+      "Allow query of replica slave", HFILL }
+    },
+    { &hf_mongo_query_flags_oplogreplay,
+      { "Op Log Reply", "mongo.query.flags.op_log_reply",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000008,
+      "Internal replication use only", HFILL }
+    },
+    { &hf_mongo_query_flags_nocursortimeout,
+      { "No Cursor Timeout", "mongo.query.flags.no_cursor_timeout",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000010,
+      "The server normally times out idle cursors after an inactivity period (10 minutes)"
+        " to prevent excess memory use. Set this option to prevent that", HFILL }
+    },
+    { &hf_mongo_query_flags_awaitdata,
+      { "AwaitData", "mongo.query.flags.awaitdata",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000020,
+      "If we are at the end of the data, block for a while rather than returning no data."
+        " After a timeout period, we do return as normal", HFILL }
+    },
+    { &hf_mongo_query_flags_exhaust,
+      { "Exhaust", "mongo.query.flags.exhaust",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000040,
+      "Stream the data down full blast in multiple more packages, on the assumption"
+        " that the client will fully read all data queried", HFILL }
+    },
+    { &hf_mongo_query_flags_partial,
+      { "Partial", "mongo.query.flags.partial",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000080,
+      "Get partial results from a mongos if some shards are down (instead of throwing an error)", HFILL }
+    },
+    { &hf_mongo_number_to_skip,
+      { "Number To Skip", "mongo.number_to_skip",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Number of documents in the skip", HFILL }
+    },
+    { &hf_mongo_number_to_return,
+      { "Number to Return", "mongo.number_to_return",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Number of documents in the return", HFILL }
+    },
+    { &hf_mongo_query,
+      { "Query", "mongo.query",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Query BSON Document", HFILL }
+    },
+    { &hf_mongo_return_field_selector,
+      { "Return Field Selector", "mongo.return_field_selector",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Return Field Selector BSON Document", HFILL }
+    },
+    { &hf_mongo_delete_flags,
+      { "Delete Flags", "mongo.delete.flags",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Bit vector of delete options.", HFILL }
+    },
+    { &hf_mongo_delete_flags_singleremove,
+      { "Single Remove", "mongo.delete.flags.singleremove",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000001,
+      "If set, the database will remove only the first matching document in the"
+        " collection. Otherwise all matching documents will be removed", HFILL }
+    },
+    { &hf_mongo_compression_info,
+      { "Compression Info", "mongo.compression",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Compressed Packet", HFILL }
+    },
+    { &hf_mongo_original_op_code,
+      { "Original OpCode", "mongo.compression.original_opcode",
+      FT_INT32, BASE_DEC, VALS(opcode_vals), 0x0,
+      "Type of request message (Wrapped)", HFILL }
+    },
+    { &hf_mongo_uncompressed_size,
+      { "Uncompressed Size", "mongo.compression.original_size",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Size of the uncompressed packet", HFILL }
+    },
+    { &hf_mongo_compressor,
+      { "Compressor", "mongo.compression.compressor",
+      FT_INT8, BASE_DEC, VALS(compressor_vals), 0x0,
+      "Compression engine", HFILL }
+    },
+    { &hf_mongo_compressed_data,
+      { "Compressed Data", "mongo.compression.compressed_data",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "The compressed data", HFILL }
+    },
+    { &hf_mongo_unsupported_compressed,
+      { "Unsupported Compressed Data", "mongo.compression.unsupported_compressed",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "This data is compressed with an unsupported compressor engine", HFILL }
+    },
+    { &hf_mongo_msg_flags,
+      { "Message Flags", "mongo.msg.flags",
+      FT_UINT32, BASE_HEX, NULL, 0x0,
+      "Bit vector of msg options.", HFILL }
+    },
+    { &hf_mongo_msg_flags_checksumpresent,
+      { "ChecksumPresent", "mongo.msg.flags.checksumpresent",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000001,
+      "The message ends with 4 bytes containing a CRC-32C [1] checksum", HFILL }
+    },
+    { &hf_mongo_msg_flags_moretocome,
+      { "MoreToCome", "mongo.msg.flags.moretocome",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00000002,
+      "Another message will follow this one without further action from the receiver", HFILL }
+    },
+    { &hf_mongo_msg_flags_exhaustallowed,
+      { "ExhaustAllowed", "mongo.msg.flags.exhaustallowed",
+      FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00010000,
+      "The client is prepared for multiple replies to this request using the moreToCome bit.", HFILL }
+    },
+    { &hf_mongo_msg_sections_section,
+      { "Section", "mongo.msg.sections.section",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_msg_sections_section_kind,
+      { "Kind", "mongo.msg.sections.section.kind",
+      FT_INT32, BASE_DEC, VALS(section_kind_vals), 0x0,
+      "Type of section", HFILL }
+    },
+    { &hf_mongo_msg_sections_section_body,
+      { "BodyDocument", "mongo.msg.sections.section.body",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_msg_sections_section_doc_sequence,
+      { "DocumentSequence", "mongo.msg.sections.section.doc_sequence",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_msg_sections_section_size,
+      { "Size", "mongo.msg.sections.section.size",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Size (in bytes) of document sequence", HFILL }
+    },
+    { &hf_mongo_msg_sections_section_doc_sequence_id,
+      { "SeqID", "mongo.msg.sections.section.doc_sequence_id",
+      FT_STRING, BASE_NONE, NULL, 0x0,
+      "Document sequence identifier", HFILL }
+    },
+    { &hf_mongo_msg_checksum,
+      { "Checksum", "mongo.msg.checksum",
+      FT_UINT32, BASE_HEX, NULL, 0x0,
+      "CRC32C checksum.", HFILL }
+    },
+    { &hf_mongo_msg_checksum_status,
+      { "Checksum Status", "mongo.msg.checksum.status",
+      FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_number_of_cursor_ids,
+      { "Number of Cursor IDS", "mongo.number_to_cursor_ids",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Number of cursorIDs in message", HFILL }
+    },
+    { &hf_mongo_elements,
+      { "Elements", "mongo.elements",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Document Elements", HFILL }
+    },
+    { &hf_mongo_element_name,
+      { "Element", "mongo.element.name",
+      FT_STRING, BASE_NONE, NULL, 0x0,
+      "Element Name", HFILL }
+    },
+    { &hf_mongo_element_type,
+      { "Type", "mongo.element.type",
+      FT_UINT8, BASE_HEX_DEC, VALS(element_type_vals), 0x0,
+      "Element Type", HFILL }
+    },
+    { &hf_mongo_element_length,
+      { "Length", "mongo.element.length",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Element Length", HFILL }
+    },
+    { &hf_mongo_element_value_boolean,
+      { "Value", "mongo.element.value.bool",
+      FT_BOOLEAN, BASE_NONE, NULL, 0x0,
+      "Element Value", HFILL }
+    },
+    { &hf_mongo_element_value_int32,
+      { "Value", "mongo.element.value.int",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Element Value", HFILL }
+    },
+    { &hf_mongo_element_value_int64,
+      { "Value", "mongo.element.value.int64",
+      FT_INT64, BASE_DEC, NULL, 0x0,
+      "Element Value", HFILL }
+    },
+    { &hf_mongo_element_value_decimal128,
+      { "Value", "mongo.element.value.decimal128",
+      FT_BYTES, BASE_NONE, NULL, 0x0,
+      "Element Value", HFILL }
+    },
+    { &hf_mongo_element_value_double,
+      { "Value", "mongo.element.value.double",
+      FT_DOUBLE, BASE_NONE, NULL, 0x0,
+      "Element Value", HFILL }
+    },
+    { &hf_mongo_element_value_string,
+      { "Value", "mongo.element.value.string",
+      FT_STRING, BASE_NONE, NULL, 0x0,
+      "Element Value", HFILL }
+    },
+    { &hf_mongo_element_value_string_length,
+      { "Length", "mongo.element.value.length",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Element Value Length", HFILL }
+    },
+    { &hf_mongo_element_value_binary,
+      { "Value", "mongo.element.value.bytes",
+      FT_BYTES, BASE_NONE, NULL, 0x0,
+      "Element Value", HFILL }
+    },
+    { &hf_mongo_element_value_binary_length,
+      { "Length", "mongo.element.value.length",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "Binary Element Length", HFILL }
+    },
+    { &hf_mongo_element_value_regex_pattern,
+      { "Value", "mongo.element.value.regex.pattern",
+      FT_STRING, BASE_NONE, NULL, 0x0,
+      "Regex Pattern", HFILL }
+    },
+    { &hf_mongo_element_value_regex_options,
+      { "Value", "mongo.element.value.regex.options",
+      FT_STRING, BASE_NONE, NULL, 0x0,
+      "Regex Options", HFILL }
+    },
+    { &hf_mongo_element_value_objectid,
+      { "ObjectID", "mongo.element.value.objectid",
+      FT_BYTES, BASE_NONE, NULL, 0x0,
+      "ObjectID Value", HFILL }
+    },
+    { &hf_mongo_element_value_objectid_time,
+      { "ObjectID Time", "mongo.element.value.objectid.time",
+      FT_INT32, BASE_DEC, NULL, 0x0,
+      "ObjectID timestampt", HFILL }
+    },
+    { &hf_mongo_element_value_objectid_host,
+      { "ObjectID Host", "mongo.element.value.objectid.host",
+      FT_UINT24, BASE_HEX, NULL, 0x0,
+      "ObjectID Host Hash", HFILL }
+    },
+    { &hf_mongo_element_value_objectid_machine_id,
+      { "ObjectID Machine", "mongo.element.value.objectid.machine_id",
+      FT_BYTES, BASE_NONE, NULL, 0x0,
+      "ObjectID machine ID", HFILL }
+    },
+    { &hf_mongo_element_value_objectid_pid,
+      { "ObjectID PID", "mongo.element.value.objectid.pid",
+      FT_UINT16, BASE_DEC, NULL, 0x0,
+      "ObjectID process ID", HFILL }
+    },
+    { &hf_mongo_element_value_objectid_inc,
+      { "ObjectID Inc", "mongo.element.value.objectid.inc",
+      FT_UINT24, BASE_DEC, NULL, 0x0,
+      "ObjectID increment", HFILL }
+    },
+    { &hf_mongo_element_value_db_ptr,
+      { "ObjectID", "mongo.element.value.db_ptr",
+      FT_BYTES, BASE_NONE, NULL, 0x0,
+      "DBPointer", HFILL }
+    },
+    { &hf_mongo_element_value_js_code,
+      { "JavaScript code", "mongo.element.value.js_code",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "JavaScript code to be evaluated", HFILL }
+    },
+    { &hf_mongo_element_value_js_scope,
+      { "JavaScript scope", "mongo.element.value.js_scope",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      "Scope document for JavaScript evaluation", HFILL }
+    },
+    { &hf_mongo_database,
+      { "database", "mongo.database",
+      FT_STRING, BASE_NONE, NULL, 0x0,
+      "the name of the database to run the command on", HFILL }
+    },
+    { &hf_mongo_commandname,
+      { "commandName", "mongo.commandname",
+      FT_STRING, BASE_NONE, NULL, 0x0,
+      "the name of the command", HFILL }
+    },
+    { &hf_mongo_metadata,
+      { "metadata", "mongo.metadata",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_commandargs,
+      { "CommandArgs", "mongo.commandargs",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_commandreply,
+      { "CommandReply", "mongo.commandreply",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_outputdocs,
+      { "OutputDocs", "mongo.outputdocs",
+      FT_NONE, BASE_NONE, NULL, 0x0,
+      NULL, HFILL }
+    },
+    { &hf_mongo_unknown,
+      { "Unknown", "mongo.unknown",
+      FT_BYTES, BASE_NONE, NULL, 0x0,
+      "Unknown Data type", HFILL }
+    },
+  };
+
+  static gint *ett[] = {
+    &ett_mongo,
+    &ett_mongo_doc,
+    &ett_mongo_elements,
+    &ett_mongo_element,
+    &ett_mongo_objectid,
+    &ett_mongo_machine_id,
+    &ett_mongo_code,
+    &ett_mongo_fcn,
+    &ett_mongo_flags,
+    &ett_mongo_compression_info,
+    &ett_mongo_sections,
+    &ett_mongo_section,
+    &ett_mongo_msg_flags,
+    &ett_mongo_doc_sequence
+  };
+
+  static ei_register_info ei[] = {
+     { &ei_mongo_document_recursion_exceeded, { "mongo.document.recursion_exceeded", PI_MALFORMED, PI_ERROR, "BSON document recursion exceeds", EXPFILL }},
+     { &ei_mongo_document_length_bad, { "mongo.document.length.bad",  PI_MALFORMED, PI_ERROR, "BSON document length bad", EXPFILL }},
+     { &ei_mongo_unknown, { "mongo.unknown.expert", PI_UNDECODED, PI_WARN, "Unknown Data (not interpreted)", EXPFILL }},
+     { &ei_mongo_unsupported_compression, { "mongo.unsupported_compression.expert", PI_UNDECODED, PI_WARN, "This packet was compressed with an unsupported compressor", EXPFILL }},
+     { &ei_mongo_too_large_compressed, { "mongo.too_large_compressed.expert", PI_UNDECODED, PI_WARN, "The size of the uncompressed packet exceeded the maximum allowed value", EXPFILL }},
+     { &ei_mongo_msg_checksum, { "mongo.bad_checksum.expert", PI_UNDECODED, PI_ERROR, "Bad checksum", EXPFILL }},
+  };
+
+  proto_mongo = proto_register_protocol("Mongo Wire Protocol", "MONGO", "mongo");
+
+  /* Allow dissector to find be found by name. */
+  mongo_handle = register_dissector("mongo", dissect_mongo, proto_mongo);
+
+  proto_register_field_array(proto_mongo, hf, array_length(hf));
+  proto_register_subtree_array(ett, array_length(ett));
+  expert_mongo = expert_register_protocol(proto_mongo);
+  expert_register_field_array(expert_mongo, ei, array_length(ei));
+}
+
+
+void
+proto_reg_handoff_mongo(void)
+{
+  dissector_add_uint_with_preference("tcp.port", TCP_PORT_MONGO, mongo_handle);
+  ssl_dissector_add(TCP_PORT_MONGO, mongo_handle);
+}
+/*
+ * Editor modelines
+ *
+ * Local Variables:
+ * c-basic-offset: 2
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * ex: set shiftwidth=2 tabstop=8 expandtab:
+ * :indentSize=2:tabSize=8:noTabs=true:
+ */