Merge pull request #9 from RobertDaleSmith/cjh/only-connect-to-mouthpads

Limit dongle to only connect to MouthPads

Author: RobertDaleSmith

ncs/app/src/ble_central.c

@@ -49,6 +49,9 @@ static ble_scan_mode_t scan_mode = SCAN_MODE_NORMAL;
 static int64_t additional_scan_start_time = 0;
 #define ADDITIONAL_SCAN_TIMEOUT_MS 10000  /* 10 second timeout for additional scan */
 
+#define MOUTHPAD_COMPANY_ID        0x4147
+#define MOUTHPAD_MFR_DATA_PAYLOAD  "MP1"
+
 /* Track if any bonded devices are advertising in current scan session */
 static bool bonded_device_seen_advertising = false;
 
@@ -64,6 +67,7 @@ struct device_uuid_state {
 	bt_addr_le_t addr;
 	bool has_hid;
 	bool has_nus;
+	bool has_mfr_data;
 	int8_t rssi;
 	int64_t timestamp;
 };
@@ -74,6 +78,7 @@ static K_MUTEX_DEFINE(tracked_devices_mutex);
 /* Device type detection */
 static bool is_nus_device(const struct bt_scan_device_info *device_info);
 static bool is_hid_device(const struct bt_scan_device_info *device_info);
+static bool is_mouthpad_manufacturer_data(const struct bt_scan_device_info *device_info);
 
 /* Callback functions for external modules */
 static ble_central_connected_cb_t connected_cb;
@@ -310,6 +315,11 @@ static void scan_filter_match(struct bt_scan_device_info *device_info,
 			      struct bt_scan_filter_match *filter_match,
 			      bool connectable)
 {
+	/* Ignore callbacks if we are no longer actively scanning */
+	if (connection_state != BLE_CENTRAL_STATE_SCANNING) {
+		return;
+	}
+
 	char addr[BT_ADDR_LE_STR_LEN];
 
 	bt_addr_le_to_str(device_info->recv_info->addr, addr, sizeof(addr));
@@ -354,6 +364,7 @@ static void scan_filter_match(struct bt_scan_device_info *device_info,
 
 	if (has_hid) dev_state->has_hid = true;
 	if (has_nus) dev_state->has_nus = true;
+	if (is_mouthpad_manufacturer_data(device_info)) dev_state->has_mfr_data = true;
 	dev_state->rssi = rssi;
 	dev_state->timestamp = k_uptime_get();
 
@@ -368,6 +379,11 @@ static void scan_filter_match(struct bt_scan_device_info *device_info,
 		return;
 	}
 
+	if (!is_bonded && !dev_state->has_mfr_data) {
+		LOG_DBG("Skipping device %s: missing expected manufacturer data", addr);
+		return;
+	}
+
 	/* CRITICAL: Set connecting state IMMEDIATELY before any logging or processing
 	 * This ensures status queries return CONNECTING as soon as we decide to connect */
 	connection_state = BLE_CENTRAL_STATE_CONNECTING;
@@ -835,6 +851,39 @@ static bool is_hid_device(const struct bt_scan_device_info *device_info)
 	return ctx.found;
 }
 
+static bool mfr_data_search_cb(struct bt_data *data, void *user_data)
+{
+	bool *found = (bool *)user_data;
+
+	if (data->type == BT_DATA_MANUFACTURER_DATA) {
+		if (data->data_len >= 2 + sizeof(MOUTHPAD_MFR_DATA_PAYLOAD) - 1 &&
+		    sys_get_le16(data->data) == MOUTHPAD_COMPANY_ID &&
+		    memcmp(data->data + 2, MOUTHPAD_MFR_DATA_PAYLOAD,
+			   sizeof(MOUTHPAD_MFR_DATA_PAYLOAD) - 1) == 0) {
+			LOG_INF("Manufacturer data matches");
+			*found = true;
+			return false; /* stop parsing */
+		}
+		LOG_INF("Manufacturer data does not match expected values");
+	}
+
+	return true; /* continue parsing */
+}
+
+static bool is_mouthpad_manufacturer_data(const struct bt_scan_device_info *device_info)
+{
+	bool found = false;
+
+	if (device_info->adv_data) {
+		struct net_buf_simple_state state;
+		net_buf_simple_save(device_info->adv_data, &state);
+		bt_data_parse(device_info->adv_data, mfr_data_search_cb, &found);
+		net_buf_simple_restore(device_info->adv_data, &state);
+	}
+
+	return found;
+}
+
 
 /* Scan work handler */
 static void scan_work_handler(struct k_work *item)