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/* packet-sparkplug.c
* Routines for Sparkplug dissection
* Copyright 2021 Graham Bloice <graham.bloice<at>trihedral.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/expert.h>
/*
* See
*
* https://cirrus-link.com/mqtt-sparkplug-tahu/
*
* and the specification is at
*
* https://www.eclipse.org/tahu/spec/Sparkplug%20Topic%20Namespace%20and%20State%20ManagementV2.2-with%20appendix%20B%20format%20-%20Eclipse.pdf
*
*/
/* Prototypes */
/* (Required to prevent [-Wmissing-prototypes] warnings */
void proto_reg_handoff_sparkplug(void);
void proto_register_sparkplug(void);
/* Initialize the protocol field */
static int proto_sparkplugb;
/* Initialize the subtree pointers */
static int ett_sparkplugb;
static int ett_sparkplugb_namespace;
/* The handle to the protobuf dissector */
dissector_handle_t protobuf_handle;
/* The hf items */
static int hf_sparkplugb_namespace;
static int hf_sparkplugb_groupid;
static int hf_sparkplugb_messagetype;
static int hf_sparkplugb_edgenodeid;
static int hf_sparkplugb_deviceid;
/* The expert info items */
static expert_field ei_sparkplugb_missing_groupid;
static expert_field ei_sparkplugb_missing_messagetype;
static expert_field ei_sparkplugb_missing_edgenodeid;
static gboolean
dissect_sparkplugb(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
proto_item *ti;
proto_tree *sparkplugb_tree, *namespace_tree;
gchar **topic_elements, **current_element;
char *topic = (char *)data;
/* Confirm the expected topic data is present */
if (topic == NULL)
return FALSE;
/* Parse the topic into the elements */
topic_elements = g_strsplit(topic, "/", 5);
/* Heuristic check that the first element of the topic is the SparkplugB namespace */
if (!topic_elements || (g_strcmp0("spBv1.0", topic_elements[0]) != 0)) {
g_strfreev(topic_elements);
return FALSE;
}
/* Make entries in Protocol column */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "SparkplugB");
/* Adjust the info column */
col_clear(pinfo->cinfo, COL_INFO);
col_append_sep_str(pinfo->cinfo, COL_INFO, NULL, "SparkplugB");
/* create display subtree for the protocol */
ti = proto_tree_add_item(tree, proto_sparkplugb, tvb, 0, -1, ENC_NA);
sparkplugb_tree = proto_item_add_subtree(ti, ett_sparkplugb);
/* Add the elements parsed out from the topic string */
namespace_tree = proto_tree_add_subtree(sparkplugb_tree, tvb, 0, 0, ett_sparkplugb_namespace, &ti, "Topic Namespace");
proto_item_set_generated(ti);
current_element = topic_elements;
ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_namespace, tvb, 0, 0, current_element[0]);
proto_item_set_generated(ti);
current_element += 1;
if (current_element[0]) {
ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_groupid, tvb, 0, 0, current_element[0]);
proto_item_set_generated(ti);
}
else {
expert_add_info(pinfo, namespace_tree, &ei_sparkplugb_missing_groupid);
return FALSE;
}
/* Adjust the info column text with the message type */
current_element += 1;
if (current_element[0]) {
col_append_sep_str(pinfo->cinfo, COL_INFO, NULL, current_element[0]);
col_set_fence(pinfo->cinfo, COL_INFO);
ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_messagetype, tvb, 0, 0, current_element[0]);
proto_item_set_generated(ti);
}
else {
expert_add_info(pinfo, namespace_tree, &ei_sparkplugb_missing_messagetype);
return FALSE;
}
current_element += 1;
if (current_element[0]) {
ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_edgenodeid, tvb, 0, 0, current_element[0]);
proto_item_set_generated(ti);
}
else {
expert_add_info(pinfo, namespace_tree, &ei_sparkplugb_missing_edgenodeid);
return FALSE;
}
/* Device ID is optional */
current_element += 1;
if (current_element[0]) {
ti = proto_tree_add_string(namespace_tree, hf_sparkplugb_deviceid, tvb, 0, 0, current_element[0]);
proto_item_set_generated(ti);
}
g_strfreev(topic_elements);
/* Now handoff the Payload message to the protobuf dissector */
call_dissector_with_data(protobuf_handle, tvb, pinfo, sparkplugb_tree, "message,com.cirruslink.sparkplug.protobuf.Payload");
return TRUE;
}
static bool dissect_sparkplugb_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data)
{
return (bool)dissect_sparkplugb(tvb, pinfo, parent_tree, data);
}
void proto_register_sparkplug(void)
{
expert_module_t* expert_sparkplugb;
static int *ett[] = {
&ett_sparkplugb,
&ett_sparkplugb_namespace
};
static hf_register_info hf[] = {
{&hf_sparkplugb_namespace, {"Namespace", "sparkplugb.namespace", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
{&hf_sparkplugb_groupid, {"Group ID", "sparkplugb.groupid", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
{&hf_sparkplugb_messagetype, {"Message Type", "sparkplugb.messagetype", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
{&hf_sparkplugb_edgenodeid, {"Edge Node ID", "sparkplugb.edgenodeid", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
{&hf_sparkplugb_deviceid, {"Device ID", "sparkplugb.deviceid", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL}},
};
static ei_register_info ei[] = {
{ &ei_sparkplugb_missing_groupid, { "sparkplugb.missing_groupid", PI_MALFORMED, PI_ERROR, "Missing Group ID", EXPFILL }},
{ &ei_sparkplugb_missing_messagetype, { "sparkplugb.missing_messagetype", PI_MALFORMED, PI_ERROR, "Missing Message Type", EXPFILL }},
{ &ei_sparkplugb_missing_edgenodeid, { "sparkplugb.missing_edgenodeid", PI_MALFORMED, PI_ERROR, "Missing Edge Node ID", EXPFILL }},
};
/* Register the protocol name and description, fields and trees */
proto_sparkplugb = proto_register_protocol("SparkplugB", "SparkplugB", "sparkplugb");
register_dissector("sparkplugb", dissect_sparkplugb, proto_sparkplugb);
proto_register_field_array(proto_sparkplugb, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_sparkplugb = expert_register_protocol(proto_sparkplugb);
expert_register_field_array(expert_sparkplugb, ei, array_length(ei));
}
void proto_reg_handoff_sparkplug(void)
{
protobuf_handle = find_dissector_add_dependency("protobuf", proto_sparkplugb);
/* register as heuristic dissector with MQTT */
heur_dissector_add("mqtt.topic", dissect_sparkplugb_heur, "SparkplugB over MQTT",
"sparkplugb_mqtt", proto_sparkplugb, HEURISTIC_ENABLE);
}
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