epan/dissectors/packet-sparkplug.c

   1 /* packet-sparkplug.c
   2  * Routines for Sparkplug dissection
   3  * Copyright 2021 Graham Bloice <graham.bloice<at>trihedral.com>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 #include "config.h"
  13 #include <epan/packet.h>
  14 #include <epan/expert.h>
  15
  16 /*
  17  * See
  18  *
  19  * https://cirrus-link.com/mqtt-sparkplug-tahu/
  20  *
  21  * and the specification is at
  22  *
  23  * https://www.eclipse.org/tahu/spec/Sparkplug%20Topic%20Namespace%20and%20State%20ManagementV2.2-with%20appendix%20B%20format%20-%20Eclipse.pdf
  24  *
  25  */
  26
  27 /* Prototypes */
  28 /* (Required to prevent [-Wmissing-prototypes] warnings */
  29 void proto_reg_handoff_sparkplug(void);
  30 void proto_register_sparkplug(void);
  31
  32 /* Initialize the protocol field */
  33 static int proto_sparkplugb;
  34
  35 /* Initialize the subtree pointers */
  36 static int ett_sparkplugb;
  37 static int ett_sparkplugb_namespace;
  38
  39 /* The handle to the protobuf dissector */
  40 dissector_handle_t protobuf_handle;
  41
  42 /* The hf items */
  43 static int hf_sparkplugb_namespace;
  44 static int hf_sparkplugb_groupid;
  45 static int hf_sparkplugb_messagetype;
  46 static int hf_sparkplugb_edgenodeid;
  47 static int hf_sparkplugb_deviceid;
  48
  49 /* The expert info items */
  50 static expert_field ei_sparkplugb_missing_groupid;
  51 static expert_field ei_sparkplugb_missing_messagetype;
  52 static expert_field ei_sparkplugb_missing_edgenodeid;
  53
  54 static gboolean
  55 dissect_sparkplugb(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
  56 {
  57     proto_item *ti;
  58     proto_tree *sparkplugb_tree, *namespace_tree;
  59     gchar **topic_elements, **current_element;
  60     char *topic = (char *)data;
  61
  62     /* Confirm the expected topic data is present */
  63     if (topic == NULL)
  64       return FALSE;
  65
  66     /* Parse the topic into the elements */
  67     topic_elements = g_strsplit(topic, "/", 5);
  68
  69     /* Heuristic check that the first element of the topic is the SparkplugB namespace */
  70     if (!topic_elements || (g_strcmp0("spBv1.0", topic_elements[0]) != 0)) {
  71         g_strfreev(topic_elements);
  72         return FALSE;
  73     }
  74
  75     /* Make entries in Protocol column */
  76     col_set_str(pinfo->cinfo, COL_PROTOCOL, "SparkplugB");
  77
  78     /* Adjust the info column */
  79     col_clear(pinfo->cinfo, COL_INFO);
  80     col_append_sep_str(pinfo->cinfo, COL_INFO, NULL, "SparkplugB");
  81
  82     /* create display subtree for the protocol */
  83     ti = proto_tree_add_item(tree, proto_sparkplugb, tvb, 0, -1, ENC_NA);
  84     sparkplugb_tree = proto_item_add_subtree(ti, ett_sparkplugb);
  85
  86     /* Add the elements parsed out from the topic string */
  87     namespace_tree = proto_tree_add_subtree(sparkplugb_tree, tvb, 0, 0, ett_sparkplugb_namespace, &ti, "Topic Namespace");
  88     proto_item_set_generated(ti);
  89
  90     current_element = topic_elements;
  91     ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_namespace, tvb, 0, 0, current_element[0]);
  92     proto_item_set_generated(ti);
  93
  94     current_element += 1;
  95     if (current_element[0]) {
  96         ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_groupid, tvb, 0, 0, current_element[0]);
  97         proto_item_set_generated(ti);
  98     }
  99     else {
 100         expert_add_info(pinfo, namespace_tree, &ei_sparkplugb_missing_groupid);
 101         return FALSE;
 102     }
 103
 104     /* Adjust the info column text with the message type */
 105     current_element += 1;
 106     if (current_element[0]) {
 107         col_append_sep_str(pinfo->cinfo, COL_INFO, NULL, current_element[0]);
 108         col_set_fence(pinfo->cinfo, COL_INFO);
 109
 110         ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_messagetype, tvb, 0, 0, current_element[0]);
 111         proto_item_set_generated(ti);
 112     }
 113     else {
 114         expert_add_info(pinfo, namespace_tree, &ei_sparkplugb_missing_messagetype);
 115         return FALSE;
 116     }
 117
 118     current_element += 1;
 119     if (current_element[0]) {
 120         ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_edgenodeid, tvb, 0, 0, current_element[0]);
 121         proto_item_set_generated(ti);
 122     }
 123     else {
 124         expert_add_info(pinfo, namespace_tree, &ei_sparkplugb_missing_edgenodeid);
 125         return FALSE;
 126     }
 127
 128     /* Device ID is optional */
 129     current_element += 1;
 130     if (current_element[0]) {
 131         ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_deviceid, tvb, 0, 0, current_element[0]);
 132         proto_item_set_generated(ti);
 133     }
 134
 135     g_strfreev(topic_elements);
 136
 137     /* Now handoff the Payload message to the protobuf dissector */
 138     call_dissector_with_data(protobuf_handle, tvb, pinfo, sparkplugb_tree, "message,com.cirruslink.sparkplug.protobuf.Payload");
 139
 140     return TRUE;
 141 }
 142
 143 static bool dissect_sparkplugb_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data)
 144 {
 145         return (bool)dissect_sparkplugb(tvb, pinfo, parent_tree, data);
 146 }
 147
 148 void proto_register_sparkplug(void)
 149 {
 150     expert_module_t* expert_sparkplugb;
 151
 152     static int *ett[] = {
 153         &ett_sparkplugb,
 154         &ett_sparkplugb_namespace
 155     };
 156
 157     static hf_register_info hf[] = {
 158         {&hf_sparkplugb_namespace, {"Namespace", "sparkplugb.namespace", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
 159         {&hf_sparkplugb_groupid, {"Group ID", "sparkplugb.groupid", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
 160         {&hf_sparkplugb_messagetype, {"Message Type", "sparkplugb.messagetype", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
 161         {&hf_sparkplugb_edgenodeid, {"Edge Node ID", "sparkplugb.edgenodeid", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
 162         {&hf_sparkplugb_deviceid, {"Device ID", "sparkplugb.deviceid", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
 163     };
 164
 165     static ei_register_info ei[] = {
 166         { &ei_sparkplugb_missing_groupid, { "sparkplugb.missing_groupid", PI_MALFORMED, PI_ERROR, "Missing Group ID", EXPFILL }},
 167         { &ei_sparkplugb_missing_messagetype, { "sparkplugb.missing_messagetype", PI_MALFORMED, PI_ERROR, "Missing Message Type", EXPFILL }},
 168         { &ei_sparkplugb_missing_edgenodeid, { "sparkplugb.missing_edgenodeid", PI_MALFORMED, PI_ERROR, "Missing Edge Node ID", EXPFILL }},
 169     };
 170
 171     /* Register the protocol name and description, fields and trees */
 172     proto_sparkplugb = proto_register_protocol("SparkplugB", "SparkplugB", "sparkplugb");
 173     register_dissector("sparkplugb", dissect_sparkplugb, proto_sparkplugb);
 174
 175     proto_register_field_array(proto_sparkplugb, hf, array_length(hf));
 176     proto_register_subtree_array(ett, array_length(ett));
 177
 178     expert_sparkplugb = expert_register_protocol(proto_sparkplugb);
 179     expert_register_field_array(expert_sparkplugb, ei, array_length(ei));
 180 }
 181
 182 void proto_reg_handoff_sparkplug(void)
 183 {
 184     protobuf_handle = find_dissector_add_dependency("protobuf", proto_sparkplugb);
 185
 186     /* register as heuristic dissector with MQTT */
 187     heur_dissector_add("mqtt.topic", dissect_sparkplugb_heur, "SparkplugB over MQTT",
 188                        "sparkplugb_mqtt", proto_sparkplugb, HEURISTIC_ENABLE);
 189 }