plugins/epan/opcua/opcua_application_layer.c

   1 /******************************************************************************
   2 ** Copyright (C) 2006-2007 ascolab GmbH. All Rights Reserved.
   3 ** Web: http://www.ascolab.com
   4 **
   5 ** SPDX-License-Identifier: GPL-2.0-or-later
   6 **
   7 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
   8 ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
   9 **
  10 ** Project: OpcUa Wireshark Plugin
  11 **
  12 ** Description: OpcUa Application Layer Decoder.
  13 **
  14 ** Author: Gerhard Gappmeier <gerhard.gappmeier@ascolab.com>
  15 ******************************************************************************/
  16
  17 #include "config.h"
  18
  19 #include <epan/packet.h>
  20 #include "opcua_application_layer.h"
  21
  22 /** NodeId encoding mask table */
  23 static const value_string g_nodeidmasks[] = {
  24     { 0x00, "Two byte encoded Numeric" },
  25     { 0x01, "Four byte encoded Numeric" },
  26     { 0x02, "Numeric of arbitrary length" },
  27     { 0x03, "String" },
  28     { 0x04, "GUID" },
  29     { 0x05, "Opaque" },
  30     { 0, NULL }
  31 };
  32
  33 /** Service type table */
  34 extern const value_string g_requesttypes[];
  35
  36 static int hf_opcua_nodeid_encodingmask;
  37 static int hf_opcua_app_nsid;
  38 static int hf_opcua_app_numeric;
  39
  40 /** Register application layer types. */
  41 void registerApplicationLayerTypes(int proto)
  42 {
  43     /** header field definitions */
  44     static hf_register_info hf[] =
  45     {
  46         /* id                               full name                    abbreviation                       type       display   strings               bitmask blurb HFILL */
  47         {&hf_opcua_nodeid_encodingmask,    {"NodeId EncodingMask",       "opcua.servicenodeid.encodingmask", FT_UINT8,  BASE_HEX, VALS(g_nodeidmasks),  0x0,    NULL, HFILL}},
  48         {&hf_opcua_app_nsid,               {"NodeId Namespace Index",    "opcua.servicenodeid.nsid",         FT_UINT8,  BASE_DEC, NULL,                 0x0,    NULL, HFILL}},
  49         {&hf_opcua_app_numeric,            {"NodeId Identifier Numeric", "opcua.servicenodeid.numeric",      FT_UINT32, BASE_DEC, VALS(g_requesttypes), 0x0,    NULL, HFILL}}
  50     };
  51
  52     proto_register_field_array(proto, hf, array_length(hf));
  53 }
  54
  55 /** Decodes the service nodeid without modifying the tree or offset.
  56  * Service NodeIds are alsways numeric.
  57  */
  58 int getServiceNodeId(tvbuff_t *tvb, int offset)
  59 {
  60     uint8_t EncodingMask;
  61     uint32_t Numeric = 0;
  62
  63     EncodingMask = tvb_get_uint8(tvb, offset);
  64     offset++;
  65
  66     switch(EncodingMask)
  67     {
  68     case 0x00: /* two byte node id */
  69         Numeric = tvb_get_uint8(tvb, offset);
  70         break;
  71     case 0x01: /* four byte node id */
  72         offset+=1;
  73         Numeric = tvb_get_letohs(tvb, offset);
  74         break;
  75     case 0x02: /* numeric, that does not fit into four bytes */
  76         offset+=2;
  77         Numeric = tvb_get_letohl(tvb, offset);
  78         break;
  79     case 0x03: /* string */
  80     case 0x04: /* guid */
  81     case 0x05: /* opaque*/
  82         /* NOT USED */
  83         break;
  84     };
  85
  86     return Numeric;
  87 }
  88
  89 /** Parses an OpcUa Service NodeId and returns the service type.
  90  * In this cases the NodeId is always from type numeric and NSId = 0.
  91  */
  92 int parseServiceNodeId(proto_tree *tree, tvbuff_t *tvb, int *pOffset)
  93 {
  94     int     iOffset = *pOffset;
  95     uint8_t EncodingMask;
  96     uint32_t Numeric = 0;
  97
  98     EncodingMask = tvb_get_uint8(tvb, iOffset);
  99     proto_tree_add_item(tree, hf_opcua_nodeid_encodingmask, tvb, iOffset, 1, ENC_LITTLE_ENDIAN);
 100     iOffset++;
 101
 102     switch(EncodingMask)
 103     {
 104     case 0x00: /* two byte node id */
 105         Numeric = tvb_get_uint8(tvb, iOffset);
 106         proto_tree_add_item(tree, hf_opcua_app_numeric, tvb, iOffset, 1, ENC_LITTLE_ENDIAN);
 107         iOffset+=1;
 108         break;
 109     case 0x01: /* four byte node id */
 110         proto_tree_add_item(tree, hf_opcua_app_nsid, tvb, iOffset, 1, ENC_LITTLE_ENDIAN);
 111         iOffset+=1;
 112         Numeric = tvb_get_letohs(tvb, iOffset);
 113         proto_tree_add_item(tree, hf_opcua_app_numeric, tvb, iOffset, 2, ENC_LITTLE_ENDIAN);
 114         iOffset+=2;
 115         break;
 116     case 0x02: /* numeric, that does not fit into four bytes */
 117         proto_tree_add_item(tree, hf_opcua_app_nsid, tvb, iOffset, 2, ENC_LITTLE_ENDIAN);
 118         iOffset+=2;
 119         Numeric = tvb_get_letohl(tvb, iOffset);
 120         proto_tree_add_item(tree, hf_opcua_app_numeric, tvb, iOffset, 4, ENC_LITTLE_ENDIAN);
 121         iOffset+=4;
 122         break;
 123     case 0x03: /* string */
 124     case 0x04: /* guid */
 125     case 0x05: /* opaque*/
 126         /* NOT USED */
 127         break;
 128     };
 129
 130     *pOffset = iOffset;
 131
 132     return Numeric;
 133 }
 134
 135 /*
 136  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 137  *
 138  * Local variables:
 139  * c-basic-offset: 4
 140  * tab-width: 8
 141  * indent-tabs-mode: nil
 142  * End:
 143  *
 144  * vi: set shiftwidth=4 tabstop=8 expandtab:
 145  * :indentSize=4:tabSize=8:noTabs=true:
 146  */