/*
* Copyright (C) 2018 BlueKitchen GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* 4. Any redistribution, use, or modification is done solely for
* personal benefit and not for any commercial purpose or for
* monetary gain.
*
* THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
* RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Please inquire about commercial licensing options at
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*
*/
#define __BTSTACK_FILE__ "att_delayed_read_response.c"
// *****************************************************************************
/* EXAMPLE_START(att_delayed_read_response): LE Peripheral - Delayed Read Response
*
* @text If the value for a GATT Chararacteristic isn't available, the value
* ATT_READ_RESPONSE_PENDING can be returned. When the value is available,
* att_server_read_response_ready is then called to complete the ATT request.
*/
// *****************************************************************************
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "att_delayed_read_response.h"
#include "btstack.h"
#define ATT_VALUE_DELAY_MS 3000
#define ATT_VALUE_INVALID_MS 5000
/* @section Main Application Setup
*
* @text Listing MainConfiguration shows main application code.
* It initializes L2CAP, the Security Manager and configures the ATT Server with the pre-compiled
* ATT Database generated from $le_counter.gatt$.
* Additionally, it enables the Battery Service Server with the current battery level.
* Finally, it configures the advertisements and boots the Bluetooth stack.
* In this example, the Advertisement contains the Flags attribute and the device name.
* The flag 0x06 indicates: LE General Discoverable Mode and BR/EDR not supported.
*/
/* LISTING_START(MainConfiguration): Init L2CAP SM ATT Server */
static btstack_timer_source_t att_timer;
static hci_con_handle_t con_handle;
static int value_ready;
static uint16_t att_read_callback(hci_con_handle_t con_handle, uint16_t att_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size);
const uint8_t adv_data[] = {
// Flags general discoverable, BR/EDR not supported
0x02, 0x01, 0x06,
// Name
0x0b, 0x09, 'L', 'E', ' ', 'C', 'o', 'u', 'n', 't', 'e', 'r',
};
const uint8_t adv_data_len = sizeof(adv_data);
const char * test_string = "Delayed response";
static void example_setup(void){
l2cap_init();
// setup le device db
le_device_db_init();
// setup SM: Display only
sm_init();
// setup ATT server
att_server_init(profile_data, att_read_callback, NULL);
// setup advertisements
uint16_t adv_int_min = 0x0030;
uint16_t adv_int_max = 0x0030;
uint8_t adv_type = 0;
bd_addr_t null_addr;
memset(null_addr, 0, 6);
gap_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 0, null_addr, 0x07, 0x00);
gap_advertisements_set_data(adv_data_len, (uint8_t*) adv_data);
gap_advertisements_enable(1);
}
/* LISTING_END */
/*
* @section att_invalidate_value Handler
*
* @text The att_invalidate_value handler 'invalidates' the value of the single Characteristic provided in this example
*/
static void att_invalidate_value(struct btstack_timer_source *ts){
UNUSED(ts);
printf("Value got stale\n");
value_ready = 0;
}
/*
* @section att_update_value Handler
*
* @text The att_update_value handler 'updates' the value of the single Characteristic provided in this example
*/
/* LISTING_START(att_read_delay): ATT Read Delay Handler */
#ifdef ENABLE_ATT_DELAYED_READ_RESPONSE
static void att_update_value(struct btstack_timer_source *ts){
UNUSED(ts);
value_ready = 1;
// trigger ATT Server to try request again
int status = att_server_read_response_ready(con_handle);
printf("Value updated -> complete ATT request - status %02x\n", status);
// simulated value becoming stale again
att_timer.process = &att_invalidate_value;
btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS);
btstack_run_loop_add_timer(&att_timer);
}
#endif
/* LISTING_END */
/*
* @section ATT Read
*
* @text The ATT Server handles all reads to constant data. For dynamic data like the custom characteristic, the registered
* att_read_callback is called. To handle long characteristics and long reads, the att_read_callback is first called
* with buffer == NULL, to request the total value length. Then it will be called again requesting a chunk of the value.
* See Listing attRead.
*/
/* LISTING_START(attRead): ATT Read */
// ATT Client Read Callback for Dynamic Data
// - if buffer == NULL, don't copy data, just return size of value
// - if buffer != NULL, copy data and return number bytes copied
// @param offset defines start of attribute value
static uint16_t att_read_callback(hci_con_handle_t connection_handle, uint16_t att_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){
#ifdef ENABLE_ATT_DELAYED_READ_RESPONSE
switch (att_handle){
case ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE:
if (value_ready){
return att_read_callback_handle_blob((const uint8_t *)test_string, strlen(test_string), offset, buffer, buffer_size);
} else {
printf("Read callback for handle %02x, but value not ready -> report response pending\n", att_handle);
con_handle = connection_handle;
return ATT_READ_RESPONSE_PENDING;
}
break;
case ATT_READ_RESPONSE_PENDING:
// virtual handle indicating all attributes have been queried
printf("Read callback for virtual handle %02x - all attributes have been queried (important for read multiple or read by type) -> start updating values\n", att_handle);
// simulated delayed response for example
att_timer.process = &att_update_value;
btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS);
btstack_run_loop_add_timer(&att_timer);
return 0;
default:
break;
}
#else
// useless code when ENABLE_ATT_DELAYED_READ_RESPONSE is not defined - but avoids built errors
if (att_handle == ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE){
printf("ENABLE_ATT_DELAYED_READ_RESPONSE not defined in btstack_config.h, responding right away");
return att_read_callback_handle_blob((const uint8_t *)test_string, strlen(test_string), offset, buffer, buffer_size);
}
#endif
return 0;
}
/* LISTING_END */
int btstack_main(void);
int btstack_main(void)
{
example_setup();
// turn on!
hci_power_control(HCI_POWER_ON);
return 0;
}
/* EXAMPLE_END */