9e1865e48e
Only reference DataSaverEnabled map on V+ platform because the information in map before platform V is not time-precise. See comment in this commit for detail. Bug: 288340533 Test: presubmit Change-Id: I0795e88e6006e6d24d27b63c31d0e3ed81d0262c
87 lines
3.6 KiB
C++
87 lines
3.6 KiB
C++
/*
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* Copyright (C) 2023 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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#define LOG_TAG "DnsBpfHelper"
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#include "DnsBpfHelper.h"
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#include <android-base/logging.h>
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#include <android-modules-utils/sdk_level.h>
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namespace android {
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namespace net {
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#define RETURN_IF_RESULT_NOT_OK(result) \
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do { \
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if (!result.ok()) { \
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LOG(ERROR) << "L" << __LINE__ << " " << __func__ << ": " << strerror(result.error().code()); \
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return result.error(); \
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} \
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} while (0)
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base::Result<void> DnsBpfHelper::init() {
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if (!android::modules::sdklevel::IsAtLeastT()) {
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LOG(ERROR) << __func__ << ": Unsupported before Android T.";
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return base::Error(EOPNOTSUPP);
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}
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RETURN_IF_RESULT_NOT_OK(mConfigurationMap.init(CONFIGURATION_MAP_PATH));
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RETURN_IF_RESULT_NOT_OK(mUidOwnerMap.init(UID_OWNER_MAP_PATH));
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RETURN_IF_RESULT_NOT_OK(mDataSaverEnabledMap.init(DATA_SAVER_ENABLED_MAP_PATH));
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return {};
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}
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base::Result<bool> DnsBpfHelper::isUidNetworkingBlocked(uid_t uid, bool metered) {
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if (is_system_uid(uid)) return false;
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if (!mConfigurationMap.isValid() || !mUidOwnerMap.isValid()) {
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LOG(ERROR) << __func__
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<< ": BPF maps are not ready. Forgot to call ADnsHelper_init?";
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return base::Error(EUNATCH);
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}
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auto enabledRules = mConfigurationMap.readValue(UID_RULES_CONFIGURATION_KEY);
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RETURN_IF_RESULT_NOT_OK(enabledRules);
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auto value = mUidOwnerMap.readValue(uid);
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uint32_t uidRules = value.ok() ? value.value().rule : 0;
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// For doze mode, battery saver, low power standby.
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if (isBlockedByUidRules(enabledRules.value(), uidRules)) return true;
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// For data saver.
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// DataSaverEnabled map on V+ platforms is the only reliable source of information about the
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// current data saver status. While ConnectivityService offers two ways to update this map for U
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// and V+, the U- platform implementation can have delays, potentially leading to inaccurate
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// results. Conversely, the V+ platform implementation is synchronized with the actual data saver
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// state, making it a trustworthy source. Since this library primarily serves DNS resolvers,
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// relying solely on V+ data prevents erroneous blocking of DNS queries.
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if (android::modules::sdklevel::IsAtLeastV() && metered) {
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// The background data setting (PENALTY_BOX_MATCH) and unrestricted data usage setting
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// (HAPPY_BOX_MATCH) for individual apps override the system wide Data Saver setting.
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if (uidRules & PENALTY_BOX_MATCH) return true;
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if (uidRules & HAPPY_BOX_MATCH) return false;
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auto dataSaverSetting = mDataSaverEnabledMap.readValue(DATA_SAVER_ENABLED_KEY);
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RETURN_IF_RESULT_NOT_OK(dataSaverSetting);
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return dataSaverSetting.value();
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}
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return false;
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}
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} // namespace net
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} // namespace android
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