src/eir.c

/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2011  Nokia Corporation
 *  Copyright (C) 2011  Marcel Holtmann <marcel@holtmann.org>
 *
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <errno.h>
#include <stdlib.h>
#include <stdint.h>
#include <glib.h>

#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/sdp.h>

#include "glib-helper.h"
#include "eir.h"

void eir_data_free(struct eir_data *eir)
{
	g_slist_free_full(eir->services, g_free);
	eir->services = NULL;
	g_free(eir->name);
	eir->name = NULL;
}

static void eir_parse_uuid16(struct eir_data *eir, void *data, uint8_t len)
{
	uint16_t *uuid16 = data;
	uuid_t service;
	char *uuid_str;
	unsigned int i;

	service.type = SDP_UUID16;
	for (i = 0; i < len / 2; i++, uuid16++) {
		service.value.uuid16 = btohs(bt_get_unaligned(uuid16));
		uuid_str = bt_uuid2string(&service);
		eir->services = g_slist_append(eir->services, uuid_str);
	}
}

static void eir_parse_uuid32(struct eir_data *eir, void *data, uint8_t len)
{
	uint32_t *uuid32 = data;
	uuid_t service;
	char *uuid_str;
	unsigned int i;

	service.type = SDP_UUID32;
	for (i = 0; i < len / 4; i++, uuid32++) {
		service.value.uuid32 = btohl(bt_get_unaligned(uuid32));
		uuid_str = bt_uuid2string(&service);
		eir->services = g_slist_append(eir->services, uuid_str);
	}
}

static void eir_parse_uuid128(struct eir_data *eir, uint8_t *data, uint8_t len)
{
	uint8_t *uuid_ptr = data;
	uuid_t service;
	char *uuid_str;
	unsigned int i;
	int k;

	service.type = SDP_UUID128;
	for (i = 0; i < len / 16; i++) {
		for (k = 0; k < 16; k++)
			service.value.uuid128.data[k] = uuid_ptr[16 - k - 1];
		uuid_str = bt_uuid2string(&service);
		eir->services = g_slist_append(eir->services, uuid_str);
		uuid_ptr += 16;
	}
}

int eir_parse(struct eir_data *eir, uint8_t *eir_data, uint8_t eir_len)
{
	uint16_t len = 0;

	eir->flags = -1;

	/* No EIR data to parse */
	if (eir_data == NULL)
		return 0;

	while (len < eir_len - 1) {
		uint8_t field_len = eir_data[0];
		uint8_t data_len, *data = &eir_data[2];

		/* Check for the end of EIR */
		if (field_len == 0)
			break;

		len += field_len + 1;

		/* Do not continue EIR Data parsing if got incorrect length */
		if (len > eir_len)
			break;

		data_len = field_len - 1;

		switch (eir_data[1]) {
		case EIR_UUID16_SOME:
		case EIR_UUID16_ALL:
			eir_parse_uuid16(eir, data, data_len);
			break;

		case EIR_UUID32_SOME:
		case EIR_UUID32_ALL:
			eir_parse_uuid32(eir, data, data_len);
			break;

		case EIR_UUID128_SOME:
		case EIR_UUID128_ALL:
			eir_parse_uuid128(eir, data, data_len);
			break;

		case EIR_FLAGS:
			if (data_len > 0)
				eir->flags = *data;
			break;

		case EIR_NAME_SHORT:
		case EIR_NAME_COMPLETE:
			/* Some vendors put a NUL byte terminator into
			 * the name */
			while (data_len > 0 && data[data_len - 1] == '\0')
				data_len--;

			if (!g_utf8_validate((char *) data, data_len, NULL))
				break;

			g_free(eir->name);

			eir->name = g_strndup((char *) data, data_len);
			eir->name_complete = eir_data[1] == EIR_NAME_COMPLETE;
			break;

		case EIR_CLASS_OF_DEV:
			if (data_len < 3)
				break;
			memcpy(eir->dev_class, data, 3);
			break;

		case EIR_GAP_APPEARANCE:
			if (data_len < 2)
				break;
			eir->appearance = bt_get_le16(data);
			break;
		}

		eir_data += field_len + 1;
	}

	return 0;
}

#define SIZEOF_UUID128 16

static void eir_generate_uuid128(GSList *list, uint8_t *ptr, uint16_t *eir_len)
{
	int i, k, uuid_count = 0;
	uint16_t len = *eir_len;
	uint8_t *uuid128;
	gboolean truncated = FALSE;

	/* Store UUIDs in place, skip 2 bytes to write type and length later */
	uuid128 = ptr + 2;

	for (; list; list = list->next) {
		struct uuid_info *uuid = list->data;
		uint8_t *uuid128_data = uuid->uuid.value.uuid128.data;

		if (uuid->uuid.type != SDP_UUID128)
			continue;

		/* Stop if not enough space to put next UUID128 */
		if ((len + 2 + SIZEOF_UUID128) > HCI_MAX_EIR_LENGTH) {
			truncated = TRUE;
			break;
		}

		/* Check for duplicates, EIR data is Little Endian */
		for (i = 0; i < uuid_count; i++) {
			for (k = 0; k < SIZEOF_UUID128; k++) {
				if (uuid128[i * SIZEOF_UUID128 + k] !=
					uuid128_data[SIZEOF_UUID128 - 1 - k])
					break;
			}
			if (k == SIZEOF_UUID128)
				break;
		}

		if (i < uuid_count)
			continue;

		/* EIR data is Little Endian */
		for (k = 0; k < SIZEOF_UUID128; k++)
			uuid128[uuid_count * SIZEOF_UUID128 + k] =
				uuid128_data[SIZEOF_UUID128 - 1 - k];

		len += SIZEOF_UUID128;
		uuid_count++;
	}

	if (uuid_count > 0 || truncated) {
		/* EIR Data length */
		ptr[0] = (uuid_count * SIZEOF_UUID128) + 1;
		/* EIR Data type */
		ptr[1] = truncated ? EIR_UUID128_SOME : EIR_UUID128_ALL;
		len += 2;
		*eir_len = len;
	}
}

void eir_create(const char *name, int8_t tx_power, uint16_t did_vendor,
			uint16_t did_product, uint16_t did_version,
			uint16_t did_source, GSList *uuids, uint8_t *data)
{
	GSList *l;
	uint8_t *ptr = data;
	uint16_t eir_len = 0;
	uint16_t uuid16[HCI_MAX_EIR_LENGTH / 2];
	int i, uuid_count = 0;
	gboolean truncated = FALSE;
	size_t name_len;

	name_len = strlen(name);

	if (name_len > 0) {
		/* EIR Data type */
		if (name_len > 48) {
			name_len = 48;
			ptr[1] = EIR_NAME_SHORT;
		} else
			ptr[1] = EIR_NAME_COMPLETE;

		/* EIR Data length */
		ptr[0] = name_len + 1;

		memcpy(ptr + 2, name, name_len);

		eir_len += (name_len + 2);
		ptr += (name_len + 2);
	}

	if (tx_power != 0) {
		*ptr++ = 2;
		*ptr++ = EIR_TX_POWER;
		*ptr++ = (uint8_t) tx_power;
		eir_len += 3;
	}

	if (did_vendor != 0x0000) {
		*ptr++ = 9;
		*ptr++ = EIR_DEVICE_ID;
		*ptr++ = (did_source & 0x00ff);
		*ptr++ = (did_source & 0xff00) >> 8;
		*ptr++ = (did_vendor & 0x00ff);
		*ptr++ = (did_vendor & 0xff00) >> 8;
		*ptr++ = (did_product & 0x00ff);
		*ptr++ = (did_product & 0xff00) >> 8;
		*ptr++ = (did_version & 0x00ff);
		*ptr++ = (did_version & 0xff00) >> 8;
		eir_len += 10;
	}

	/* Group all UUID16 types */
	for (l = uuids; l != NULL; l = g_slist_next(l)) {
		struct uuid_info *uuid = l->data;

		if (uuid->uuid.type != SDP_UUID16)
			continue;

		if (uuid->uuid.value.uuid16 < 0x1100)
			continue;

		if (uuid->uuid.value.uuid16 == PNP_INFO_SVCLASS_ID)
			continue;

		/* Stop if not enough space to put next UUID16 */
		if ((eir_len + 2 + sizeof(uint16_t)) > HCI_MAX_EIR_LENGTH) {
			truncated = TRUE;
			break;
		}

		/* Check for duplicates */
		for (i = 0; i < uuid_count; i++)
			if (uuid16[i] == uuid->uuid.value.uuid16)
				break;

		if (i < uuid_count)
			continue;

		uuid16[uuid_count++] = uuid->uuid.value.uuid16;
		eir_len += sizeof(uint16_t);
	}

	if (uuid_count > 0) {
		/* EIR Data length */
		ptr[0] = (uuid_count * sizeof(uint16_t)) + 1;
		/* EIR Data type */
		ptr[1] = truncated ? EIR_UUID16_SOME : EIR_UUID16_ALL;

		ptr += 2;
		eir_len += 2;

		for (i = 0; i < uuid_count; i++) {
			*ptr++ = (uuid16[i] & 0x00ff);
			*ptr++ = (uuid16[i] & 0xff00) >> 8;
		}
	}

	/* Group all UUID128 types */
	if (eir_len <= HCI_MAX_EIR_LENGTH - 2)
		eir_generate_uuid128(uuids, ptr, &eir_len);
}

gboolean eir_has_data_type(uint8_t *data, size_t len, uint8_t type)
{
	uint8_t field_len;
	size_t parsed = 0;

	while (parsed < len - 1) {
		field_len = data[0];

		if (field_len == 0)
			break;

		parsed += field_len + 1;

		if (parsed > len)
			break;

		if (data[1] == type)
			return TRUE;

		data += field_len + 1;
	}

	return FALSE;
}

size_t eir_append_data(uint8_t *eir, size_t eir_len, uint8_t type,
						uint8_t *data, size_t data_len)
{
	eir[eir_len++] = sizeof(type) + data_len;
	eir[eir_len++] = type;
	memcpy(&eir[eir_len], data, data_len);
	eir_len += data_len;

	return eir_len;
}

size_t eir_length(uint8_t *eir, size_t maxlen)
{
	uint8_t field_len;
	size_t parsed = 0, length = 0;

	while (parsed < maxlen - 1) {
		field_len = eir[0];

		if (field_len == 0)
			break;

		parsed += field_len + 1;

		if (parsed > maxlen)
			break;

		length = parsed;
		eir += field_len + 1;
	}

	return length;
}