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/* packet-lwm2mtlv.c
 * Routines for LWM2M TLV dissection
 * References:
 *     OMA LWM2M Specification: OMA-TS-LightweightM2M-V1_0-20151214-C.pdf
 *     available from
 *     http://technical.openmobilealliance.org/Technical/technical-information/release-program/current-releases/oma-lightweightm2m-v1-0
 *
 * Copyright 2016, Christoph Burger-Scheidlin
 *
 * 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/to_str.h>
#include <epan/uat.h>
#include <wsutil/str_util.h>

#include "packet-http.h"

void proto_register_lwm2mtlv(void);
void proto_reg_handoff_lwm2mtlv(void);

static void parseArrayOfElements(tvbuff_t *tvb, proto_tree *tlv_tree, const char *uri_path);

static int proto_lwm2mtlv = -1;

static int hf_lwm2mtlv_header                    = -1;
static int hf_lwm2mtlv_type_type                 = -1;
static int hf_lwm2mtlv_type_length_of_identifier = -1;
static int hf_lwm2mtlv_type_length_of_length     = -1;
static int hf_lwm2mtlv_type_length               = -1;
static int hf_lwm2mtlv_type_ignored              = -1;

static int hf_lwm2mtlv_identifier                = -1;
static int hf_lwm2mtlv_length                    = -1;
static int hf_lwm2mtlv_value                     = -1;
static int hf_lwm2mtlv_value_string              = -1;
static int hf_lwm2mtlv_value_integer             = -1;
static int hf_lwm2mtlv_value_float               = -1;
static int hf_lwm2mtlv_value_double              = -1;
static int hf_lwm2mtlv_value_boolean             = -1;
static int hf_lwm2mtlv_value_timestamp           = -1;

static gint ett_lwm2mtlv                  = -1;
static gint ett_lwm2mtlv_header           = -1;
static gint ett_lwm2mtlv_resource         = -1;
static gint ett_lwm2mtlv_resourceInstance = -1;
static gint ett_lwm2mtlv_resourceArray    = -1;
static gint ett_lwm2mtlv_objectInstance   = -1;



typedef enum {
	OBJECT_INSTANCE   = 0,
	RESOURCE_INSTANCE = 1,
	RESOURCE_ARRAY    = 2,
	RESOURCE          = 3
} lwm2m_identifier_t;

static const value_string identifiers[] = {
	{ OBJECT_INSTANCE,   "Object Instance" },
	{ RESOURCE_INSTANCE, "Resource Instance" },
	{ RESOURCE_ARRAY,    "Multiple Resources" },
	{ RESOURCE,          "Resource with value" },
	{ 0, NULL }
};

static const value_string length_identifier[] = {
	{ 0x00, "1 byte identifier" },
	{ 0x01, "2 bytes identifier" },
	{ 0, NULL }
};

static const value_string length_type[] = {
	{ 0x00, "No length field" },
	{ 0x01, "1 byte length field" },
	{ 0x02, "2 bytes length field" },
	{ 0x03, "3 bytes length field" },
	{ 0, NULL }
};

typedef struct
{
	guint type;
	guint length_of_identifier;
	guint length_of_length;
	guint length_of_value;
	guint identifier;
	guint length;
	guint totalLength;
} lwm2mElement_t;

typedef struct _lwm2m_resource_t {
	guint   object_id;
	guint   resource_id;
	char   *name;
	guint   data_type;
	gint   *hf_id;
	char   *field_name;
} lwm2m_resource_t;

#define DATA_TYPE_NONE    0
#define DATA_TYPE_STRING  1
#define DATA_TYPE_INTEGER 2
#define DATA_TYPE_FLOAT   3
#define DATA_TYPE_BOOLEAN 4
#define DATA_TYPE_OPAQUE  5
#define DATA_TYPE_TIME    6
#define DATA_TYPE_OBJLNK  7

static const value_string data_types[] = {
	{ DATA_TYPE_NONE,    "None"    },
	{ DATA_TYPE_STRING,  "String"  },
	{ DATA_TYPE_INTEGER, "Integer" },
	{ DATA_TYPE_FLOAT,   "Float"   },
	{ DATA_TYPE_BOOLEAN, "Boolean" },
	{ DATA_TYPE_OPAQUE,  "Opaque"  },
	{ DATA_TYPE_TIME,    "Time"    },
	{ DATA_TYPE_OBJLNK,  "Objlnk"  },
	{ 0, NULL }
};

/* LwM2M Objects defined by OMA (Normative) */
static lwm2m_resource_t lwm2m_oma_resources[] =
{
	/* LwM2M Security (0) */
	{ 0, 0,  "LwM2M Server URI", DATA_TYPE_STRING, NULL, NULL },
	{ 0, 1,  "Bootstrap-Server", DATA_TYPE_BOOLEAN, NULL, NULL },
	{ 0, 2,  "Security Mode", DATA_TYPE_INTEGER, NULL, NULL },
	{ 0, 3,  "Public Key or Identity", DATA_TYPE_OPAQUE, NULL, NULL },
	{ 0, 4,  "Server Public Key", DATA_TYPE_OPAQUE, NULL, NULL },
	{ 0, 5,  "Secret Key", DATA_TYPE_OPAQUE, NULL, NULL },
	{ 0, 6,  "SMS Security Mode", DATA_TYPE_INTEGER, NULL, NULL },
	{ 0, 7,  "SMS Binding Key Parameters", DATA_TYPE_OPAQUE, NULL, NULL },
	{ 0, 8,  "SMS Binding Secret Keys", DATA_TYPE_OPAQUE, NULL, NULL },
	{ 0, 9,  "LwM2M Server SMS Number", DATA_TYPE_STRING, NULL, NULL },
	{ 0, 10, "Short Server ID", DATA_TYPE_INTEGER, NULL, NULL },
	{ 0, 11, "Client Hold Off Time", DATA_TYPE_INTEGER, NULL, NULL },
	{ 0, 12, "Bootstrap-Server Account Timeout", DATA_TYPE_INTEGER, NULL, NULL },

	/* LwM2M Server (1) */
	{ 1, 0,  "Short Server ID", DATA_TYPE_INTEGER, NULL, NULL },
	{ 1, 1,  "Lifetime", DATA_TYPE_INTEGER, NULL, NULL },
	{ 1, 2,  "Default Minimum Period", DATA_TYPE_INTEGER, NULL, NULL },
	{ 1, 3,  "Default Maximum Period", DATA_TYPE_INTEGER, NULL, NULL },
	{ 1, 4,  "Disable", DATA_TYPE_NONE, NULL, NULL },
	{ 1, 5,  "Disable Timeout", DATA_TYPE_INTEGER, NULL, NULL },
	{ 1, 6,  "Notification Storing When Disabled or Offline", DATA_TYPE_BOOLEAN, NULL, NULL },
	{ 1, 7,  "Binding", DATA_TYPE_STRING, NULL, NULL },

	/* Access Control (2) */
	{ 2, 0,  "Object ID", DATA_TYPE_INTEGER, NULL, NULL },
	{ 2, 1,  "Object Instance ID", DATA_TYPE_INTEGER, NULL, NULL },
	{ 2, 2,  "ACL", DATA_TYPE_INTEGER, NULL, NULL },
	{ 2, 3,  "Access Control Owner", DATA_TYPE_INTEGER, NULL, NULL },

	/* Device (3) */
	{ 3, 0,  "Manufacturer", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 1,  "Model Number", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 2,  "Serial Number", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 3,  "Firmware Version", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 4,  "Reboot", DATA_TYPE_NONE, NULL, NULL },
	{ 3, 5,  "Factory Reset", DATA_TYPE_NONE, NULL, NULL },
	{ 3, 6,  "Available Power Sources", DATA_TYPE_INTEGER, NULL, NULL },
	{ 3, 7,  "Power Source Voltage", DATA_TYPE_INTEGER, NULL, NULL },
	{ 3, 8,  "Power Source Current", DATA_TYPE_INTEGER, NULL, NULL },
	{ 3, 9,  "Battery Level", DATA_TYPE_INTEGER, NULL, NULL },
	{ 3, 10, "Memory Free", DATA_TYPE_INTEGER, NULL, NULL },
	{ 3, 11, "Error Code", DATA_TYPE_INTEGER, NULL, NULL },
	{ 3, 12, "Reset Error Code", DATA_TYPE_NONE, NULL, NULL },
	{ 3, 13, "Current Time", DATA_TYPE_TIME, NULL, NULL },
	{ 3, 14, "UTC Offset", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 15, "Timezone", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 16, "Supported Binding and Modes", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 17, "Device Type", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 18, "Hardware Version", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 19, "Software Version", DATA_TYPE_STRING, NULL, NULL },
	{ 3, 20, "Battery Status", DATA_TYPE_INTEGER, NULL, NULL },
	{ 3, 21, "Memory Total", DATA_TYPE_INTEGER, NULL, NULL },
	{ 3, 22, "ExtDevInfo", DATA_TYPE_OBJLNK, NULL, NULL },

	/* Connectivity Monitoring (4) */
	{ 4, 0,  "Network Bearer", DATA_TYPE_INTEGER, NULL, NULL },
	{ 4, 1,  "Available Network Bearer", DATA_TYPE_INTEGER, NULL, NULL },
	{ 4, 2,  "Radio Signal Strength", DATA_TYPE_INTEGER, NULL, NULL },
	{ 4, 3,  "Link Quality", DATA_TYPE_INTEGER, NULL, NULL },
	{ 4, 4,  "IP Addresses", DATA_TYPE_STRING, NULL, NULL },
	{ 4, 5,  "Router IP Addresses", DATA_TYPE_STRING, NULL, NULL },
	{ 4, 6,  "Link Utilization", DATA_TYPE_INTEGER, NULL, NULL },
	{ 4, 7,  "APN", DATA_TYPE_STRING, NULL, NULL },
	{ 4, 8,  "Cell ID", DATA_TYPE_INTEGER, NULL, NULL },
	{ 4, 9,  "SMNC", DATA_TYPE_INTEGER, NULL, NULL },
	{ 4, 10, "SMCC", DATA_TYPE_INTEGER, NULL, NULL },

	/* Firmware Update (5) */
	{ 5, 0,  "Package", DATA_TYPE_OPAQUE, NULL, NULL },
	{ 5, 1,  "Package URI", DATA_TYPE_STRING, NULL, NULL },
	{ 5, 2,  "Update", DATA_TYPE_NONE, NULL, NULL },
	{ 5, 3,  "State", DATA_TYPE_INTEGER, NULL, NULL },
	/* { 5, 4,  "", DATA_TYPE_NONE, NULL, NULL }, */
	{ 5, 5,  "Update Result", DATA_TYPE_INTEGER, NULL, NULL },
	{ 5, 6,  "PkgName", DATA_TYPE_STRING, NULL, NULL },
	{ 5, 7,  "PkgVersion", DATA_TYPE_STRING, NULL, NULL },
	{ 5, 8,  "Firmware Update Protocol Support", DATA_TYPE_INTEGER, NULL, NULL },
	{ 5, 9,  "Firmware Update Delivery Method", DATA_TYPE_INTEGER, NULL, NULL },

	/* Location (6) */
	{ 6, 0,  "Latitude", DATA_TYPE_FLOAT, NULL, NULL },
	{ 6, 1,  "Longitude", DATA_TYPE_FLOAT, NULL, NULL },
	{ 6, 2,  "Altitude", DATA_TYPE_FLOAT, NULL, NULL },
	{ 6, 3,  "Radius", DATA_TYPE_FLOAT, NULL, NULL },
	{ 6, 4,  "Velocity", DATA_TYPE_OPAQUE, NULL, NULL },
	{ 6, 5,  "Timestamp", DATA_TYPE_TIME, NULL, NULL },
	{ 6, 6,  "Speed", DATA_TYPE_FLOAT, NULL, NULL },

	/* Connectivity Statistics (7) */
	{ 7, 0,  "SMS Tx Counter", DATA_TYPE_INTEGER, NULL, NULL },
	{ 7, 1,  "SMS Rx Counter", DATA_TYPE_INTEGER, NULL, NULL },
	{ 7, 2,  "Tx Data", DATA_TYPE_INTEGER, NULL, NULL },
	{ 7, 3,  "Rx Data", DATA_TYPE_INTEGER, NULL, NULL },
	{ 7, 4,  "Max Message Size", DATA_TYPE_INTEGER, NULL, NULL },
	{ 7, 5,  "Average Message Size", DATA_TYPE_INTEGER, NULL, NULL },
	{ 7, 6,  "Start", DATA_TYPE_NONE, NULL, NULL },
	{ 7, 7,  "Stop", DATA_TYPE_NONE, NULL, NULL },
	{ 7, 8,  "Collection Period", DATA_TYPE_INTEGER, NULL, NULL },
};

/* LwM2M Objects defined by User */
static lwm2m_resource_t *lwm2m_uat_resources;
static guint num_lwm2m_uat_resources;

static gboolean lwm2m_resource_update_cb(void *record, char **error)
{
	lwm2m_resource_t *rec = (lwm2m_resource_t *)record;
	char c;

	if (rec->name == NULL) {
		*error = g_strdup("Resource Name can't be empty");
		return FALSE;
	}

	g_strstrip(rec->name);
	if (rec->name[0] == 0) {
		*error = g_strdup("Resource Name can't be empty");
		return FALSE;
	}

	g_free(rec->field_name);
	rec->field_name = g_ascii_strdown(rec->name, -1);
	for (size_t i = 0; i < strlen(rec->field_name); i++) {
		if (rec->field_name[i] == ' ' || rec->field_name[i] == '.') {
			rec->field_name[i] = '_';
		}
	}

	/* Check for invalid characters (to avoid asserting out when registering the field). */
	c = proto_check_field_name(rec->field_name);
	if (c) {
		*error = g_strdup_printf("Resource Name can't contain '%c'", c);
		return FALSE;
	}

	*error = NULL;
	return TRUE;
}

static void *lwm2m_resource_copy_cb(void *dest, const void *source, size_t len _U_)
{
	const lwm2m_resource_t *s = (const lwm2m_resource_t *)source;
	lwm2m_resource_t *d = (lwm2m_resource_t *)dest;

	d->object_id = s->object_id;
	d->resource_id = s->resource_id;
	d->name = g_strdup(s->name);
	d->field_name = g_strdup(s->field_name);
	d->data_type = s->data_type;

	return d;
}

static void lwm2m_resource_free_cb(void *record)
{
	lwm2m_resource_t *rec = (lwm2m_resource_t *)record;

	g_free(rec->name);
	g_free(rec->field_name);
}

static void lwm2m_add_resource(lwm2m_resource_t *resource, hf_register_info *hf)
{
	gchar *resource_abbrev;
	gint *hf_id;

	hf_id = g_new(gint,1);
	*hf_id = -1;

	if (resource->field_name) {
		resource_abbrev = g_strdup(resource->field_name);
	} else {
		resource_abbrev = g_ascii_strdown(resource->name, -1);
		for (size_t i = 0; i < strlen(resource_abbrev); i++) {
			if (resource_abbrev[i] == ' ' || resource_abbrev[i] == '.') {
				resource_abbrev[i] = '_';
			}
		}
	}

	resource->hf_id = hf_id;

	hf->p_id = hf_id;
	hf->hfinfo.name = g_strdup(resource->name);
	hf->hfinfo.abbrev = g_strdup_printf("lwm2mtlv.resource.%s", resource_abbrev);
	g_free (resource_abbrev);

	switch (resource->data_type) {
	case DATA_TYPE_STRING:
		hf->hfinfo.display = BASE_NONE;
		hf->hfinfo.type = FT_STRING;
		break;
	case DATA_TYPE_INTEGER:
		hf->hfinfo.display = BASE_DEC;
		hf->hfinfo.type = FT_INT64;
		break;
	case DATA_TYPE_FLOAT:
		hf->hfinfo.display = BASE_NONE;
		hf->hfinfo.type = FT_FLOAT;
		break;
	case DATA_TYPE_BOOLEAN:
		hf->hfinfo.display = BASE_DEC;
		hf->hfinfo.type = FT_BOOLEAN;
		break;
	case DATA_TYPE_TIME:
		hf->hfinfo.display = ABSOLUTE_TIME_LOCAL;
		hf->hfinfo.type = FT_ABSOLUTE_TIME;
		break;
	case DATA_TYPE_OPAQUE:
	case DATA_TYPE_OBJLNK:
	default:
		hf->hfinfo.display = BASE_NONE;
		hf->hfinfo.type = FT_BYTES;
		break;
	}
	hf->hfinfo.strings = NULL;
	hf->hfinfo.bitmask = 0;
	hf->hfinfo.blurb = NULL;
	HFILL_INIT(*hf);
}

static void lwm2m_resource_post_update_cb(void)
{
	static hf_register_info *hf;
	static guint hf_size;

	if (hf) {
		/* Deregister all fields */
		for (guint i = 0; i < hf_size; i++) {
			proto_deregister_field(proto_lwm2mtlv, *(hf[i].p_id));
			g_free (hf[i].p_id);
		}
		proto_add_deregistered_data(hf);
	}

	if (num_lwm2m_uat_resources) {
		hf = g_new0(hf_register_info, num_lwm2m_uat_resources);
		hf_size = 0;

		for (guint i = 0; i < num_lwm2m_uat_resources; i++) {
			lwm2m_add_resource(&lwm2m_uat_resources[i], &hf[hf_size++]);
		}

		proto_register_field_array(proto_lwm2mtlv, hf, hf_size);
	}
}

static gint64
decodeVariableInt(tvbuff_t *tvb, const gint offset, const guint length)
{
	switch(length)
	{
	case 1:
		return tvb_get_gint8(tvb, offset);
	case 2:
		return tvb_get_ntohis(tvb, offset);
	case 3:
		return tvb_get_ntohi24(tvb, offset);
	case 4:
		return tvb_get_ntohil(tvb, offset);
	case 5:
		return tvb_get_ntohi40(tvb, offset);
	case 6:
		return tvb_get_ntohi48(tvb, offset);
	case 7:
		return tvb_get_ntohi56(tvb, offset);
	case 8:
		return tvb_get_ntohi64(tvb, offset);
	default:
		return 0;
	}
}

UAT_DEC_CB_DEF(resource, object_id, lwm2m_resource_t)
UAT_DEC_CB_DEF(resource, resource_id, lwm2m_resource_t)
UAT_CSTRING_CB_DEF(resource, name, lwm2m_resource_t)
UAT_VS_DEF(resource, data_type, lwm2m_resource_t, guint, DATA_TYPE_NONE, "None")

static void
addTlvHeaderElements(tvbuff_t *tvb, proto_tree *tlv_tree, lwm2mElement_t *element)
{
	proto_tree_add_item(tlv_tree, hf_lwm2mtlv_type_type, tvb, 0, 1, ENC_BIG_ENDIAN);
	proto_tree_add_item(tlv_tree, hf_lwm2mtlv_type_length_of_identifier, tvb, 0, 1, ENC_BIG_ENDIAN);
	proto_tree_add_item(tlv_tree, hf_lwm2mtlv_type_length_of_length, tvb, 0, 1, ENC_BIG_ENDIAN);
	if ( element->length_of_length == 0 ) {
		proto_tree_add_item(tlv_tree, hf_lwm2mtlv_type_length, tvb, 0, 1, ENC_BIG_ENDIAN);
	} else {
		proto_tree_add_item(tlv_tree, hf_lwm2mtlv_type_ignored, tvb, 0, 1, ENC_BIG_ENDIAN);
	}

	proto_tree_add_item(tlv_tree, hf_lwm2mtlv_identifier, tvb, 1, element->length_of_identifier, ENC_BIG_ENDIAN);

	if ( element->length_of_length > 0 ) {
		proto_tree_add_item(tlv_tree, hf_lwm2mtlv_length, tvb, 1+element->length_of_identifier, element->length_of_length, ENC_BIG_ENDIAN);
	}
}

static void
addTlvHeaderTree(tvbuff_t *tvb, proto_tree *tlv_tree, lwm2mElement_t *element)
{
	proto_item *item = NULL;
	proto_tree *header_tree = NULL;

	guint valueOffset = 1 + element->length_of_identifier + element->length_of_length;

	item = proto_tree_add_item(tlv_tree, hf_lwm2mtlv_header, tvb, 0, valueOffset, ENC_NA);
	header_tree = proto_item_add_subtree(item, ett_lwm2mtlv_header);
	addTlvHeaderElements(tvb, header_tree, element);
}

static proto_tree*
addElementTree(tvbuff_t *tvb, proto_tree *tlv_tree, lwm2mElement_t *element, const lwm2m_resource_t *resource)
{
	gchar *identifier = NULL;

	if (resource) {
		identifier = wmem_strdup_printf(wmem_packet_scope(), "[%02u] %s", element->identifier, resource->name);
	} else {
		identifier = wmem_strdup_printf(wmem_packet_scope(), "[%02u]", element->identifier);
	}

	switch ( element->type )
	{
	case OBJECT_INSTANCE:
		return proto_tree_add_subtree_format(tlv_tree, tvb, 0, element->totalLength, ett_lwm2mtlv_objectInstance, NULL,
		                                     "Object Instance %02u", element->identifier);

	case RESOURCE_INSTANCE:
		return proto_tree_add_subtree_format(tlv_tree, tvb, 0, element->totalLength, ett_lwm2mtlv_resourceInstance, NULL,
		                                     "%02u", element->identifier);

	case RESOURCE_ARRAY:
		return proto_tree_add_subtree_format(tlv_tree, tvb, 0, element->totalLength, ett_lwm2mtlv_resourceArray, NULL,
		                                     "%s", identifier);

	case RESOURCE:
		return proto_tree_add_subtree_format(tlv_tree, tvb, 0, element->totalLength, ett_lwm2mtlv_resource, NULL,
		                                     "%s", identifier);
	}
	return NULL;
}

static void
addValueInterpretations(tvbuff_t *tvb, proto_tree *tlv_tree, lwm2mElement_t *element, const lwm2m_resource_t *resource)
{
	guint valueOffset;
	if ( element->length_of_value == 0 ) return;

	valueOffset = 1 + element->length_of_identifier + element->length_of_length;

	if (resource && resource->data_type != DATA_TYPE_NONE) {
		switch (resource->data_type) {
		case DATA_TYPE_STRING:
		{
			const guint8 *strval;
			proto_tree_add_item_ret_string(tlv_tree, *resource->hf_id, tvb, valueOffset, element->length_of_value, ENC_UTF_8, wmem_packet_scope(), &strval);
			proto_item_append_text(tlv_tree, ": %s", strval);
			break;
		}
		case DATA_TYPE_INTEGER:
			proto_tree_add_item(tlv_tree, *resource->hf_id, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			proto_item_append_text(tlv_tree, ": %" G_GINT64_FORMAT, decodeVariableInt(tvb, valueOffset, element->length_of_value));
			break;
		case DATA_TYPE_FLOAT:
			proto_tree_add_item(tlv_tree, *resource->hf_id, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			proto_item_append_text(tlv_tree, ": %." G_STRINGIFY(FLT_DIG) "g", tvb_get_ieee_float(tvb, valueOffset, ENC_BIG_ENDIAN));
			break;
		case DATA_TYPE_BOOLEAN:
		{
			gboolean boolval;
			proto_tree_add_item_ret_boolean(tlv_tree, *resource->hf_id, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN, &boolval);
			proto_item_append_text(tlv_tree, ": %s", boolval ? "True" : "False");
			break;
		}
		case DATA_TYPE_TIME:
		{
			nstime_t ts;
			ts.secs = (time_t)decodeVariableInt(tvb, valueOffset, element->length_of_value);
			ts.nsecs = 0;
			proto_tree_add_time(tlv_tree, *resource->hf_id, tvb, valueOffset, element->length_of_value, &ts);
			proto_item_append_text(tlv_tree, ": %s", abs_time_to_str(wmem_packet_scope(), &ts, ABSOLUTE_TIME_LOCAL, FALSE));
			break;
		}
		case DATA_TYPE_OPAQUE:
		case DATA_TYPE_OBJLNK:
		default:
			proto_tree_add_item(tlv_tree, *resource->hf_id, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			proto_item_append_text(tlv_tree, ": %s", tvb_bytes_to_str(wmem_packet_scope(), tvb, valueOffset, element->length_of_value));
			break;
		}
	} else {
		guint8 *str = tvb_get_string_enc(wmem_packet_scope(), tvb, valueOffset, element->length_of_value, ENC_UTF_8);
		if (isprint_utf8_string(str, element->length_of_value)) {
			proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_string, tvb, valueOffset, element->length_of_value, ENC_UTF_8|ENC_NA);
		} else {
			str = tvb_bytes_to_str(wmem_packet_scope(), tvb, valueOffset, element->length_of_value);
		}
		proto_item_append_text(tlv_tree, ": %s", str);

		switch(element->length_of_value) {
		case 0x01:
			proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_integer, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			if (tvb_get_guint8(tvb, valueOffset) < 2) {
				proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_boolean, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			}
			break;
		case 0x02:
			proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_integer, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			break;
		case 0x04:
			proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_integer, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_float, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_timestamp, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			break;
		case 0x08:
			proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_integer, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_double, tvb, valueOffset, element->length_of_value, ENC_BIG_ENDIAN);
			/* apparently, wireshark does not deal well with 8 bytes. */
			proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value_timestamp, tvb, valueOffset+4, element->length_of_value-4, ENC_BIG_ENDIAN);
			break;
		}
	}
}

static void
addValueTree(tvbuff_t *tvb, proto_tree *tlv_tree, lwm2mElement_t *element, const char *uri_path, const lwm2m_resource_t *resource)
{
	guint valueOffset = 1 + element->length_of_identifier + element->length_of_length;

	if ( element->type == RESOURCE || element->type == RESOURCE_INSTANCE ) {
		proto_tree_add_item(tlv_tree, hf_lwm2mtlv_value, tvb, valueOffset, element->length_of_value, ENC_NA);
		addValueInterpretations(tvb, tlv_tree, element, resource);
	} else {
		tvbuff_t* sub = tvb_new_subset_length(tvb, valueOffset, element->length_of_value);
		parseArrayOfElements(sub, tlv_tree, uri_path);
	}
}

static void
addTlvElement(tvbuff_t *tvb, proto_tree *tlv_tree, lwm2mElement_t *element, const char *uri_path)
{
	proto_tree *element_tree = NULL;
	const lwm2m_resource_t *resource = NULL;

	gchar **ids = wmem_strsplit(wmem_packet_scope(), uri_path, "/", 4);
	if (ids && ids[0] && ids[1] && ids[2]) {
		/* URI path is defined as:
		 *  ids[0] = Object ID
		 *  ids[1] = Object Instance
		 *  ids[2] = Resource ID
		 *  ids[3] = Resource Instance
		 */
		guint object_id = (guint)strtol(ids[0], NULL, 10);
		guint resource_id = (guint)strtol(ids[2], NULL, 10);

		/* First search OMA objects */
		for (guint i = 0; i < array_length(lwm2m_oma_resources); i++) {
			if ((object_id == lwm2m_oma_resources[i].object_id) &&
				(resource_id == lwm2m_oma_resources[i].resource_id))
			{
				resource = &lwm2m_oma_resources[i];
				break;
			}
		}

		/* Then search user configured objects */
		for (guint i = 0; i < num_lwm2m_uat_resources; i++) {
			if ((object_id == lwm2m_uat_resources[i].object_id) &&
				(resource_id == lwm2m_uat_resources[i].resource_id))
			{
				resource = &lwm2m_uat_resources[i];
				break;
			}
		}
	}

	element_tree = addElementTree(tvb, tlv_tree, element, resource);
	addTlvHeaderTree(tvb, element_tree, element);
	addValueTree(tvb, element_tree, element, uri_path, resource);
}

static guint64
decodeVariableUInt(tvbuff_t *tvb, const gint offset, const guint length)
{
	switch(length)
	{
	case 1:
		return tvb_get_guint8(tvb, offset);
	case 2:
		return tvb_get_ntohs(tvb, offset);
	case 3:
		return tvb_get_ntoh24(tvb, offset);
	case 4:
		return tvb_get_ntohl(tvb, offset);
	case 5:
		return tvb_get_ntoh40(tvb, offset);
	case 6:
		return tvb_get_ntoh48(tvb, offset);
	case 7:
		return tvb_get_ntoh56(tvb, offset);
	case 8:
		return tvb_get_ntoh64(tvb, offset);
	default:
		return 0;
	}
}

static guint parseTLVHeader(tvbuff_t *tvb, lwm2mElement_t *element)
{
	guint type_field = tvb_get_guint8(tvb, 0);
	element->type                 = (( type_field >> 6 ) & 0x03 );
	element->length_of_identifier = (( type_field >> 5 ) & 0x01 ) + 1;
	element->length_of_length     = (( type_field >> 3 ) & 0x03 );
	element->length_of_value      = (( type_field >> 0 ) & 0x07 );

	/* It is ok to shorten identifier and length_of_value, they are never more than 24 bits long */
	element->identifier = (guint) decodeVariableUInt(tvb, 1, element->length_of_identifier);
	if ( element->length_of_length > 0 ) {
		element->length_of_value = (guint) decodeVariableUInt(tvb, 1 + element->length_of_identifier, element->length_of_length);
	}

	element->totalLength = 1 + element->length_of_identifier + element->length_of_length + element->length_of_value;

	return element->totalLength;
}

static void parseArrayOfElements(tvbuff_t *tvb, proto_tree *tlv_tree, const char *uri_path)
{
	guint length;
	guint offset = 0;
	guint elementLength = 0;
	guint element_count = 0;
	lwm2mElement_t element;
	const char *next_uri_path = NULL;

	length = tvb_reported_length(tvb);

	while ( length > 0 ) {
		tvbuff_t* sub = tvb_new_subset_length(tvb, offset, length);
		elementLength = parseTLVHeader(sub, &element);
		if (uri_path) {
			next_uri_path = wmem_strdup_printf(wmem_packet_scope(), "%s/%d", uri_path, element.identifier);
		}
		addTlvElement(sub, tlv_tree, &element, next_uri_path);
		element_count++;

		length -= elementLength;
		offset += elementLength;
		if ( elementLength == 0 )
		{
			break;
		}
	}

	proto_item_append_text(tlv_tree, " (%u element%s)", element_count, plurality(element_count, "", "s"));
}

static int
dissect_lwm2mtlv(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void *data)
{
	proto_tree* lwm2mtlv_tree;
	proto_item* lwm2mtlv_item;
	http_message_info_t *message_info = (http_message_info_t *) data;
	const char *uri_path = NULL;

	if (message_info && message_info->media_str && message_info->media_str[0]) {
		uri_path = message_info->media_str;
	}

	if (tree) { /* we are being asked for details */
		lwm2mtlv_item = proto_tree_add_item(tree, proto_lwm2mtlv, tvb, 0, -1, ENC_NA);
		lwm2mtlv_tree = proto_item_add_subtree(lwm2mtlv_item, ett_lwm2mtlv);

		parseArrayOfElements(tvb, lwm2mtlv_tree, uri_path);
	}
	return tvb_captured_length(tvb);
}

void proto_register_lwm2mtlv(void)
{
	static hf_register_info hf[] = {
		{ &hf_lwm2mtlv_header,
			{ "TLV header", "lwm2mtlv.header",
				FT_NONE, BASE_NONE, NULL, 0x0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_type_type,
			{ "Type of Identifier", "lwm2mtlv.type.type",
				FT_UINT8, BASE_DEC, VALS(identifiers), 0xC0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_type_length_of_identifier,
			{ "Length of Identifier", "lwm2mtlv.type.loi",
				FT_UINT8, BASE_DEC, VALS(length_identifier), 0x20,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_type_length_of_length,
			{ "Length of Length", "lwm2mtlv.type.lol",
				FT_UINT8, BASE_DEC, VALS(length_type), 0x18,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_type_length,
			{ "Length", "lwm2mtlv.type.length",
				FT_UINT8, BASE_DEC, NULL, 0x07,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_type_ignored,
			{ "Ignored", "lwm2mtlv.type.ignored",
				FT_UINT8, BASE_DEC, NULL, 0x07,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_identifier,
			{ "Identifier", "lwm2mtlv.identifier",
				FT_UINT16, BASE_DEC, NULL, 0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_length,
			{ "Length", "lwm2mtlv.length",
				FT_UINT32, BASE_DEC, NULL, 0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_value,
			{ "Value", "lwm2mtlv.value",
				FT_BYTES, BASE_NONE, NULL, 0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_value_string,
			{ "As String", "lwm2mtlv.value.string",
				FT_STRING, BASE_NONE, NULL, 0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_value_integer,
			{ "As Integer", "lwm2mtlv.value.integer",
				FT_INT64, BASE_DEC, NULL, 0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_value_float,
			{ "As Float", "lwm2mtlv.value.float",
				FT_FLOAT, BASE_NONE, NULL, 0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_value_double,
			{ "As Double", "lwm2mtlv.value.double",
				FT_DOUBLE, BASE_NONE, NULL, 0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_value_boolean,
			{ "As Boolean", "lwm2mtlv.value.boolean",
				FT_BOOLEAN, BASE_NONE, NULL, 0,
				NULL, HFILL }
		},
		{ &hf_lwm2mtlv_value_timestamp,
			{ "As Timestamp", "lwm2mtlv.value.timestamp",
				FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0,
				NULL, HFILL }
		},
	};

	static gint* ett[] = {
		&ett_lwm2mtlv,
		&ett_lwm2mtlv_header,
		&ett_lwm2mtlv_resource,
		&ett_lwm2mtlv_resourceInstance,
		&ett_lwm2mtlv_resourceArray,
		&ett_lwm2mtlv_objectInstance
	};

	static uat_field_t lwm2m_resource_flds[] = {
		UAT_FLD_DEC(resource, object_id, "Object ID", "Object ID"),
		UAT_FLD_DEC(resource, resource_id, "Resource ID", "Resource ID"),
		UAT_FLD_CSTRING(resource, name, "Resource Name", "Resource Name"),
		UAT_FLD_VS(resource, data_type, "Data Type", data_types, "Data Type"),
		UAT_END_FIELDS
	};

	uat_t *resource_uat = uat_new("User Resource Names",
	                              sizeof(lwm2m_resource_t),
	                              "lwm2m_resource_names",
	                              TRUE,
	                              &lwm2m_uat_resources,
	                              &num_lwm2m_uat_resources,
	                              UAT_AFFECTS_DISSECTION|UAT_AFFECTS_FIELDS,
	                              "ChLwM2MResourceNames",
	                              lwm2m_resource_copy_cb,
	                              lwm2m_resource_update_cb,
	                              lwm2m_resource_free_cb,
	                              lwm2m_resource_post_update_cb,
	                              NULL,
	                              lwm2m_resource_flds);

	module_t *lwm2mtlv_module;

	/* Register our configuration options */
	proto_lwm2mtlv = proto_register_protocol (
		"Lightweight M2M TLV",
		"LwM2M-TLV",
		"lwm2mtlv"
	);

	proto_register_field_array(proto_lwm2mtlv, hf, array_length(hf));
	proto_register_subtree_array(ett, array_length(ett));

	register_dissector("lwm2mtlv", dissect_lwm2mtlv, proto_lwm2mtlv);

	lwm2mtlv_module = prefs_register_protocol(proto_lwm2mtlv, NULL);

	prefs_register_uat_preference(lwm2mtlv_module, "resource_table",
	                              "Resource Names",
	                              "User Resource Names",
	                              resource_uat);

	hf_register_info *hf2 = g_new0(hf_register_info, array_length(lwm2m_oma_resources));
	for (guint i = 0; i < array_length(lwm2m_oma_resources); i++) {
		lwm2m_add_resource(&lwm2m_oma_resources[i], &hf2[i]);
	}
	proto_register_field_array(proto_lwm2mtlv, hf2, array_length(lwm2m_oma_resources));
}

void
proto_reg_handoff_lwm2mtlv(void)
{
	static dissector_handle_t lwm2mtlv_handle;

	lwm2mtlv_handle = create_dissector_handle(dissect_lwm2mtlv, proto_lwm2mtlv);
	dissector_add_string("media_type", "application/vnd.oma.lwm2m+tlv", lwm2mtlv_handle);
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */