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230 lines
7.1 KiB
230 lines
7.1 KiB
//
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// Copyright 2016 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at:
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#include "service/low_energy_scanner.h"
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#include "service/adapter.h"
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#include "service/logging_helpers.h"
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#include "stack/include/bt_types.h"
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#include "stack/include/hcidefs.h"
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#include <base/bind.h>
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#include <base/callback.h>
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#include <base/logging.h>
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using std::lock_guard;
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using std::mutex;
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namespace bluetooth {
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namespace {
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// 31 + 31 for advertising data and scan response. This is the maximum length
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// TODO(armansito): Fix the HAL to return a concatenated blob that contains the
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// true length of each field and also provide a length parameter so that we
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// can support advertising length extensions in the future.
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const size_t kScanRecordLength = 62;
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// Returns the length of the given scan record array. We have to calculate this
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// based on the maximum possible data length and the TLV data. See TODO above
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// |kScanRecordLength|.
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size_t GetScanRecordLength(std::vector<uint8_t> bytes) {
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for (size_t i = 0, field_len = 0; i < kScanRecordLength;
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i += (field_len + 1)) {
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field_len = bytes[i];
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// Assert here that the data returned from the stack is correctly formatted
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// in TLV form and that the length of the current field won't exceed the
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// total data length.
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CHECK(i + field_len < kScanRecordLength);
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// If the field length is zero and we haven't reached the maximum length,
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// then we have found the length, as the stack will pad the data with zeros
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// accordingly.
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if (field_len == 0) return i;
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}
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// We have reached the end.
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return kScanRecordLength;
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}
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} // namespace
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// LowEnergyScanner implementation
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// ========================================================
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LowEnergyScanner::LowEnergyScanner(Adapter& adapter, const Uuid& uuid,
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int scanner_id)
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: adapter_(adapter),
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app_identifier_(uuid),
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scanner_id_(scanner_id),
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scan_started_(false),
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delegate_(nullptr) {}
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LowEnergyScanner::~LowEnergyScanner() {
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// Automatically unregister the scanner.
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VLOG(1) << "LowEnergyScanner unregistering scanner: " << scanner_id_;
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// Unregister as observer so we no longer receive any callbacks.
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hal::BluetoothGattInterface::Get()->RemoveScannerObserver(this);
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hal::BluetoothGattInterface::Get()->GetScannerHALInterface()->Unregister(
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scanner_id_);
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// Stop any scans started by this client.
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if (scan_started_.load()) StopScan();
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}
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void LowEnergyScanner::SetDelegate(Delegate* delegate) {
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lock_guard<mutex> lock(delegate_mutex_);
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delegate_ = delegate;
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}
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bool LowEnergyScanner::StartScan(const ScanSettings& settings,
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const std::vector<ScanFilter>& filters) {
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VLOG(2) << __func__;
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// Cannot start a scan if the adapter is not enabled.
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if (!adapter_.IsEnabled()) {
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LOG(ERROR) << "Cannot scan while Bluetooth is disabled";
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return false;
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}
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// TODO(jpawlowski): Push settings and filtering logic below the HAL.
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bt_status_t status =
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hal::BluetoothGattInterface::Get()->StartScan(scanner_id_);
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if (status != BT_STATUS_SUCCESS) {
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LOG(ERROR) << "Failed to initiate scanning for client: " << scanner_id_;
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return false;
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}
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scan_started_ = true;
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return true;
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}
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bool LowEnergyScanner::StopScan() {
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VLOG(2) << __func__;
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// TODO(armansito): We don't support batch scanning yet so call
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// StopRegularScanForClient directly. In the future we will need to
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// conditionally call a batch scan API here.
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bt_status_t status =
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hal::BluetoothGattInterface::Get()->StopScan(scanner_id_);
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if (status != BT_STATUS_SUCCESS) {
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LOG(ERROR) << "Failed to stop scan for client: " << scanner_id_;
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return false;
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}
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scan_started_ = false;
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return true;
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}
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const Uuid& LowEnergyScanner::GetAppIdentifier() const {
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return app_identifier_;
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}
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int LowEnergyScanner::GetInstanceId() const { return scanner_id_; }
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void LowEnergyScanner::ScanResultCallback(
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hal::BluetoothGattInterface* gatt_iface, const RawAddress& bda, int rssi,
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std::vector<uint8_t> adv_data) {
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// Ignore scan results if this client didn't start a scan.
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if (!scan_started_.load()) return;
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lock_guard<mutex> lock(delegate_mutex_);
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if (!delegate_) return;
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// TODO(armansito): Apply software filters here.
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size_t record_len = GetScanRecordLength(adv_data);
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std::vector<uint8_t> scan_record(adv_data.begin(),
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adv_data.begin() + record_len);
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ScanResult result(BtAddrString(&bda), scan_record, rssi);
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delegate_->OnScanResult(this, result);
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}
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// LowEnergyScannerFactory implementation
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// ========================================================
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LowEnergyScannerFactory::LowEnergyScannerFactory(Adapter& adapter)
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: adapter_(adapter) {
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hal::BluetoothGattInterface::Get()->AddScannerObserver(this);
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}
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LowEnergyScannerFactory::~LowEnergyScannerFactory() {
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hal::BluetoothGattInterface::Get()->RemoveScannerObserver(this);
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}
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bool LowEnergyScannerFactory::RegisterInstance(
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const Uuid& uuid, const RegisterCallback& callback) {
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VLOG(1) << __func__ << " - Uuid: " << uuid.ToString();
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lock_guard<mutex> lock(pending_calls_lock_);
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if (pending_calls_.find(uuid) != pending_calls_.end()) {
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LOG(ERROR) << "Low-Energy scanner with given Uuid already registered - "
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<< "Uuid: " << uuid.ToString();
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return false;
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}
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BleScannerInterface* hal_iface =
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hal::BluetoothGattInterface::Get()->GetScannerHALInterface();
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Uuid uuid_empty = Uuid::kEmpty;
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hal_iface->RegisterScanner(
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uuid_empty, base::Bind(&LowEnergyScannerFactory::RegisterScannerCallback,
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base::Unretained(this), callback, uuid));
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pending_calls_.insert(uuid);
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return true;
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}
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void LowEnergyScannerFactory::RegisterScannerCallback(
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const RegisterCallback& callback, const Uuid& app_uuid, uint8_t scanner_id,
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uint8_t status) {
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Uuid uuid(app_uuid);
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VLOG(1) << __func__ << " - Uuid: " << uuid.ToString();
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lock_guard<mutex> lock(pending_calls_lock_);
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auto iter = pending_calls_.find(uuid);
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if (iter == pending_calls_.end()) {
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VLOG(1) << "Ignoring callback for unknown app_id: " << uuid.ToString();
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return;
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}
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// No need to construct a scanner if the call wasn't successful.
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std::unique_ptr<LowEnergyScanner> scanner;
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BLEStatus result = BLE_STATUS_FAILURE;
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if (status == BT_STATUS_SUCCESS) {
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scanner.reset(new LowEnergyScanner(adapter_, uuid, scanner_id));
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hal::BluetoothGattInterface::Get()->AddScannerObserver(scanner.get());
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result = BLE_STATUS_SUCCESS;
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}
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// Notify the result via the result callback.
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callback(result, app_uuid, std::move(scanner));
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pending_calls_.erase(iter);
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}
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} // namespace bluetooth
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