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/**
* Copyright (c) 2022, The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <mutex>
#include <netdutils/Status.h>
#include "bpf/BpfMap.h"
#include "bpf_shared.h"
using android::bpf::BpfMap;
using android::bpf::BpfMapRO;
namespace android {
namespace net {
class BpfHandler {
public:
BpfHandler();
BpfHandler(const BpfHandler&) = delete;
BpfHandler& operator=(const BpfHandler&) = delete;
netdutils::Status init(const char* cg2_path);
/*
* Tag the socket with the specified tag and uid. In the qtaguid module, the
* first tag request that grab the spinlock of rb_tree can update the tag
* information first and other request need to wait until it finish. All the
* tag request will be addressed in the order of they obtaining the spinlock.
* In the eBPF implementation, the kernel will try to update the eBPF map
* entry with the tag request. And the hashmap update process is protected by
* the spinlock initialized with the map. So the behavior of two modules
* should be the same. No additional lock needed.
*/
int tagSocket(int sockFd, uint32_t tag, uid_t chargeUid, uid_t realUid);
/*
* The untag process is similar to tag socket and both old qtaguid module and
* new eBPF module have spinlock inside the kernel for concurrent update. No
* external lock is required.
*/
int untagSocket(int sockFd);
private:
// For testing
BpfHandler(uint32_t perUidLimit, uint32_t totalLimit);
netdutils::Status initMaps();
bool hasUpdateDeviceStatsPermission(uid_t uid);
BpfMap<uint64_t, UidTagValue> mCookieTagMap;
BpfMap<StatsKey, StatsValue> mStatsMapA;
BpfMapRO<StatsKey, StatsValue> mStatsMapB;
BpfMapRO<uint32_t, uint32_t> mConfigurationMap;
BpfMap<uint32_t, uint8_t> mUidPermissionMap;
std::mutex mMutex;
// The limit on the number of stats entries a uid can have in the per uid stats map. BpfHandler
// will block that specific uid from tagging new sockets after the limit is reached.
const uint32_t mPerUidStatsEntriesLimit;
// The limit on the total number of stats entries in the per uid stats map. BpfHandler will
// block all tagging requests after the limit is reached.
const uint32_t mTotalUidStatsEntriesLimit;
// For testing
friend class BpfHandlerTest;
};
} // namespace net
} // namespace android
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