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1 /*
2  * Copyright (C) 2019 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  *
16  */
17 
18 #pragma once
19 
20 #include <string>
21 #include <vector>
22 
23 #include <netdutils/DumpWriter.h>
24 
25 #include "LockedQueue.h"
26 
27 namespace android::net {
28 
29 // This class stores query records in a locked ring buffer. It's thread-safe for concurrent access.
30 class DnsQueryLog {
31   public:
32     static constexpr std::string_view DUMP_KEYWORD = "querylog";
33 
34     struct Record {
RecordRecord35         Record(uint32_t netId, uid_t uid, pid_t pid, const std::string& hostname,
36                const std::vector<std::string>& addrs, int timeTaken)
37             : netId(netId),
38               uid(uid),
39               pid(pid),
40               hostname(hostname),
41               addrs(addrs),
42               timeTaken(timeTaken) {}
43         const uint32_t netId;
44         const uid_t uid;
45         const pid_t pid;
46         const std::chrono::system_clock::time_point timestamp = std::chrono::system_clock::now();
47         const std::string hostname;
48         const std::vector<std::string> addrs;
49         const int timeTaken;
50     };
51 
52     // Allow the tests to set the capacity and the validaty time in milliseconds.
53     DnsQueryLog(size_t size = kDefaultLogSize,
54                 std::chrono::milliseconds time = kDefaultValidityMinutes)
mQueue(size)55         : mQueue(size), mValidityTimeMs(time) {}
56 
57     void push(Record&& record);
58     void dump(netdutils::DumpWriter& dw) const;
59 
60   private:
61     LockedRingBuffer<Record> mQueue;
62     const std::chrono::milliseconds mValidityTimeMs;
63 
64     // The capacity of the circular buffer.
65     static constexpr size_t kDefaultLogSize = 200;
66 
67     // Limit to dump the queries within last |kDefaultValidityMinutes| minutes.
68     static constexpr std::chrono::minutes kDefaultValidityMinutes{60};
69 };
70 
71 }  // namespace android::net
72