| /* |
| * Copyright (C) 2019 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 <chrono> |
| #include <deque> |
| #include <map> |
| #include <vector> |
| |
| #include <android-base/thread_annotations.h> |
| #include <netdutils/DumpWriter.h> |
| #include <netdutils/InternetAddresses.h> |
| |
| #include "ResolverStats.h" |
| #include "stats.pb.h" |
| |
| namespace android::net { |
| |
| // The overall information of a StatsRecords. |
| struct StatsData { |
| StatsData(const netdutils::IPSockAddr& ipSockAddr) : sockAddr(ipSockAddr) { |
| lastUpdate = std::chrono::steady_clock::now(); |
| }; |
| |
| // Socket address. |
| netdutils::IPSockAddr sockAddr; |
| |
| // The most recent number of records being accumulated. |
| int total = 0; |
| |
| // The map used to store the number of each rcode. |
| std::map<int, int> rcodeCounts; |
| |
| // The aggregated RTT in microseconds. |
| // For DNS-over-TCP, it includes TCP handshake. |
| // For DNS-over-TLS, it might include TCP handshake plus SSL handshake. |
| std::chrono::microseconds latencyUs = {}; |
| |
| // The last update timestamp. |
| std::chrono::time_point<std::chrono::steady_clock> lastUpdate; |
| |
| int averageLatencyMs() const; |
| std::string toString() const; |
| |
| // For testing. |
| bool operator==(const StatsData& o) const; |
| friend std::ostream& operator<<(std::ostream& os, const StatsData& data) { |
| return os << data.toString(); |
| } |
| }; |
| |
| // A circular buffer based class used to store the statistics for a server with a protocol. |
| class StatsRecords { |
| public: |
| struct Record { |
| int rcode = 0; // NS_R_NO_ERROR |
| int linux_errno = 0; // SYS_NO_ERROR |
| std::chrono::microseconds latencyUs; |
| }; |
| |
| StatsRecords(const netdutils::IPSockAddr& ipSockAddr, size_t size); |
| |
| void push(const Record& record); |
| |
| const StatsData& getStatsData() const { return mStatsData; } |
| |
| // Quantifies the quality based on the current quality factors and the latency, and normalize |
| // the value to a score between 0 to 100. |
| double score() const; |
| |
| void incrementSkippedCount(); |
| |
| private: |
| void updateStatsData(const Record& record, const bool add); |
| void updatePenalty(const Record& record); |
| |
| std::deque<Record> mRecords; |
| size_t mCapacity; |
| StatsData mStatsData; |
| |
| // A quality factor used to distinguish if the server can't be evaluated by latency alone, such |
| // as instant failure on connect. |
| int mPenalty = 0; |
| |
| // A quality factor used to prevent starvation. |
| int mSkippedCount = 0; |
| |
| // The maximum of the quantified result. As the sorting is on the basis of server latency, limit |
| // the maximal value of the quantity to 10000 in correspondence with the maximal cleartext |
| // query timeout 10000 milliseconds. This helps normalize the value of the quality to a score. |
| static constexpr int kMaxQuality = 10000; |
| }; |
| |
| // DnsStats class manages the statistics of DNS servers or MDNS multicast addresses per netId. |
| // The class itself is not thread-safe. |
| class DnsStats { |
| public: |
| using StatsMap = std::map<netdutils::IPSockAddr, StatsRecords>; |
| |
| // Add |addrs| to the map, and remove no-longer-used addresses. |
| // Return true if they are successfully added; otherwise, return false. |
| bool setAddrs(const std::vector<netdutils::IPSockAddr>& addrs, Protocol protocol); |
| |
| // Return true if |record| is successfully added into |server|'s stats; otherwise, return false. |
| bool addStats(const netdutils::IPSockAddr& server, const DnsQueryEvent& record); |
| |
| std::vector<netdutils::IPSockAddr> getSortedServers(Protocol protocol) const; |
| |
| // Returns the average query latency in microseconds. |
| std::optional<std::chrono::microseconds> getAverageLatencyUs(Protocol protocol) const; |
| |
| void dump(netdutils::DumpWriter& dw); |
| |
| std::vector<StatsData> getStats(Protocol protocol) const; |
| |
| // TODO: Compatible support for getResolverInfo(). |
| |
| static constexpr size_t kLogSize = 128; |
| |
| private: |
| std::map<Protocol, StatsMap> mStats; |
| }; |
| |
| } // namespace android::net |