ESP32-PaxCounter/src/blecsan.cpp

#ifdef BLECOUNTER

/* code snippets taken from
https://github.com/nkolban/esp32-snippets/tree/master/BLE/scanner
*/

// Basic Config
#include "globals.h"

// Bluetooth specific includes
#include <esp_bt.h>
#include <esp_bt_main.h>
#include <esp_gap_ble_api.h>
#include <esp_blufi_api.h> // needed for BLE_ADDR types, do not remove
#include <bt_types.h>

#define BT_BD_ADDR_HEX(addr)   addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]

// local Tag for logging
static const char* TAG = "bluetooth";

// defined in macsniff.cpp
bool mac_add(uint8_t *paddr, int8_t rssi, bool sniff_type);

// Prototypes
static const char *bt_addr_t_to_string(esp_ble_addr_type_t type);
static const char *btsig_gap_type(uint32_t gap_type);
static void gap_callback_handler(esp_gap_ble_cb_event_t event, esp_ble_gap_cb_param_t *param);

static const char *bt_addr_t_to_string(esp_ble_addr_type_t type) {
	switch(type) {
		case BLE_ADDR_TYPE_PUBLIC:
			return "BLE_ADDR_TYPE_PUBLIC";
		case BLE_ADDR_TYPE_RANDOM:
			return "BLE_ADDR_TYPE_RANDOM";
		case BLE_ADDR_TYPE_RPA_PUBLIC:
			return "BLE_ADDR_TYPE_RPA_PUBLIC";
		case BLE_ADDR_TYPE_RPA_RANDOM:
			return "BLE_ADDR_TYPE_RPA_RANDOM";
		default:
			return "Unknown addr_t";
	}
} // bt_addr_t_to_string

static const char *btsig_gap_type(uint32_t gap_type) {
	switch (gap_type)
	{
		case 0x01: return "Flags";
		case 0x02: return "Incomplete List of 16-bit Service Class UUIDs";
		case 0x03: return "Complete List of 16-bit Service Class UUIDs";
		case 0x04: return "Incomplete List of 32-bit Service Class UUIDs";
		case 0x05: return "Complete List of 32-bit Service Class UUIDs";
		case 0x06: return "Incomplete List of 128-bit Service Class UUIDs";
		case 0x07: return "Complete List of 128-bit Service Class UUIDs";
		case 0x08: return "Shortened Local Name";
		case 0x09: return "Complete Local Name";
		case 0x0A: return "Tx Power Level";
		case 0x0D: return "Class of Device";
		case 0x0E: return "Simple Pairing Hash C/C-192";
		case 0x0F: return "Simple Pairing Randomizer R/R-192";
		case 0x10: return "Device ID/Security Manager TK Value";
		case 0x11: return "Security Manager Out of Band Flags";
		case 0x12: return "Slave Connection Interval Range";
		case 0x14: return "List of 16-bit Service Solicitation UUIDs";
		case 0x1F: return "List of 32-bit Service Solicitation UUIDs";
		case 0x15: return "List of 128-bit Service Solicitation UUIDs";
		case 0x16: return "Service Data - 16-bit UUID";
		case 0x20: return "Service Data - 32-bit UUID";
		case 0x21: return "Service Data - 128-bit UUID";
		case 0x22: return "LE Secure Connections Confirmation Value";
		case 0x23: return "LE Secure Connections Random Value";
		case 0x24: return "URI";
		case 0x25: return "Indoor Positioning";
		case 0x26: return "Transport Discovery Data";
		case 0x17: return "Public Target Address";
		case 0x18: return "Random Target Address";
		case 0x19: return "Appearance";
		case 0x1A: return "Advertising Interval";
		case 0x1B: return "LE Bluetooth Device Address";
		case 0x1C: return "LE Role";
		case 0x1D: return "Simple Pairing Hash C-256";
		case 0x1E: return "Simple Pairing Randomizer R-256";
		case 0x3D: return "3D Information Data";
		case 0xFF: return "Manufacturer Specific Data";
		
		default: 
			return "Unknown type";
	}
} // btsig_gap_type

// using IRAM_:ATTR here to speed up callback function
IRAM_ATTR static void gap_callback_handler(esp_gap_ble_cb_event_t event, esp_ble_gap_cb_param_t *param)
{
	esp_ble_gap_cb_param_t *p = (esp_ble_gap_cb_param_t *)param;
	
	ESP_LOGD(TAG, "BT payload rcvd -> type: 0x%.2x -> %s", *p->scan_rst.ble_adv, btsig_gap_type(*p->scan_rst.ble_adv));		

	switch (event) 
	{
		case ESP_GAP_BLE_SCAN_PARAM_SET_COMPLETE_EVT:
			// restart scan
			ESP_ERROR_CHECK(esp_ble_gap_start_scanning(BLESCANTIME));
		break;
		
		case ESP_GAP_BLE_SCAN_RESULT_EVT:
			// evaluate scan results	
			if ( p->scan_rst.search_evt == ESP_GAP_SEARCH_INQ_CMPL_EVT) // Inquiry complete, scan is done
			{	// restart scan
				ESP_ERROR_CHECK(esp_ble_gap_start_scanning(BLESCANTIME));
				return;
			}
			
			if (p->scan_rst.search_evt == ESP_GAP_SEARCH_INQ_RES_EVT) // Inquiry result for a peer device
			{	// evaluate sniffed packet
				ESP_LOGD(TAG, "Device address (bda): %02x:%02x:%02x:%02x:%02x:%02x", BT_BD_ADDR_HEX(p->scan_rst.bda));
				ESP_LOGD(TAG, "Addr_type           : %s", bt_addr_t_to_string(p->scan_rst.ble_addr_type));
				ESP_LOGD(TAG, "RSSI                : %d", p->scan_rst.rssi);

				if ((cfg.rssilimit) && (p->scan_rst.rssi < cfg.rssilimit )) { // rssi is negative value
     				ESP_LOGI(TAG, "BLTH RSSI %d -> ignoring (limit: %d)", p->scan_rst.rssi, cfg.rssilimit);
					break;
    			}

				#ifdef VENDORFILTER
					
					if ((p->scan_rst.ble_addr_type == BLE_ADDR_TYPE_RANDOM) || (p->scan_rst.ble_addr_type == BLE_ADDR_TYPE_RPA_RANDOM)) {
						ESP_LOGD(TAG, "BT device filtered");	
						break;
					}

				#endif

				// add this device and show new count total if it was not previously added
           		mac_add((uint8_t *) p->scan_rst.bda, p->scan_rst.rssi, MAC_SNIFF_BLE);	
				
				/* to be improved in vendorfilter if:
				
				// you can search for elements in the payload using the
				// function esp_ble_resolve_adv_data()
				//
				// Like this, that scans for the "Complete name" (looking inside the payload buffer)
				// uint8_t len;
				// uint8_t *data = esp_ble_resolve_adv_data(p->scan_rst.ble_adv, ESP_BLE_AD_TYPE_NAME_CMPL, &len);

				filter BLE devices using their advertisements to get filter alternative to vendor OUI
				if vendorfiltering is on, we ...
				- want to count: mobile phones and tablets
				- don't want to count: beacons, peripherals (earphones, headsets, printers), cars and machines
				see
				https://github.com/nkolban/ESP32_BLE_Arduino/blob/master/src/BLEAdvertisedDevice.cpp

				http://www.libelium.com/products/meshlium/smartphone-detection/

				https://www.question-defense.com/2013/01/12/bluetooth-cod-bluetooth-class-of-deviceclass-of-service-explained

				https://www.bluetooth.com/specifications/assigned-numbers/baseband

				"The Class of Device (CoD) in case of Bluetooth which allows us to differentiate the type of 
				device (smartphone, handsfree, computer, LAN/network AP). With this parameter we can 
				differentiate among pedestrians and vehicles."

				*/

			} // evaluate sniffed packet
		break;

		default:
        break;
	}
} // gap_callback_handler


esp_err_t register_ble_callback(void) {
	ESP_LOGI(TAG, "Register GAP callback");
	
	// This function is called to occur gap event, such as scan result.
	//register the scan callback function to the gap module
	ESP_ERROR_CHECK(esp_ble_gap_register_callback(&gap_callback_handler));

	static esp_ble_scan_params_t ble_scan_params = 
	{	
		.scan_type              = BLE_SCAN_TYPE_PASSIVE,
		.own_addr_type          = BLE_ADDR_TYPE_RANDOM,
		
		#ifdef VENDORFILTER
			.scan_filter_policy     = BLE_SCAN_FILTER_ALLOW_WLIST_PRA_DIR,
			// ADV_IND, ADV_NONCONN_IND, ADV_SCAN_IND packets are used for broadcasting 
			// data in broadcast applications (e.g., Beacons), so we don't want them in vendorfilter mode
		#else
			.scan_filter_policy     = BLE_SCAN_FILTER_ALLOW_ALL,
		#endif

		.scan_interval          = (uint16_t) (cfg.blescantime * 10 / 0.625), // Time = N * 0.625 msec
		.scan_window            = (uint16_t) (BLESCANWINDOW / 0.625)		// Time = N * 0.625 msec	
	};

	ESP_LOGI(TAG, "Set GAP scan parameters");

	// This function is called to set scan parameters.			
 	ESP_ERROR_CHECK(esp_ble_gap_set_scan_params(&ble_scan_params));
	
	return ESP_OK;

} // register_ble_callback

void start_BLEscan(void){
	ESP_LOGI(TAG, "Initializing bluetooth scanner ...");

	// Initialize BT controller to allocate task and other resource. 
	esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
	bt_cfg.controller_task_stack_size = BLESTACKSIZE; // set BT stack size to value configured in paxcounter.conf
	ESP_ERROR_CHECK(esp_bt_controller_init(&bt_cfg));
	ESP_ERROR_CHECK(esp_bt_controller_enable(ESP_BT_MODE_BTDM));

	// Init and alloc the resource for bluetooth stack, must be done prior to every bluetooth stuff
	ESP_ERROR_CHECK(esp_bluedroid_init());
	ESP_ERROR_CHECK(esp_bluedroid_enable()); 

	// Register callback function for capturing bluetooth packets
	ESP_ERROR_CHECK(register_ble_callback());

	ESP_LOGI(TAG, "Bluetooth scanner started");
} // start_BLEscan

void stop_BLEscan(void){
	ESP_LOGI(TAG, "Shutting down bluetooth scanner ...");
	ESP_ERROR_CHECK(esp_ble_gap_register_callback(NULL));
	ESP_ERROR_CHECK(esp_bluedroid_disable());
	ESP_ERROR_CHECK(esp_bluedroid_deinit());
	ESP_ERROR_CHECK(esp_bt_controller_disable());
	ESP_ERROR_CHECK(esp_bt_controller_deinit());
	ESP_LOGI(TAG, "Bluetooth scanner stopped");
} // stop_BLEscan

#endif // BLECOUNTER