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 #include <regex>
18 #include <thread>
19 
20 #include <android-base/strings.h>
21 #include <android-base/test_utils.h>
22 #include <gtest/gtest.h>
23 
24 #include "DnsQueryLog.h"
25 
26 using namespace std::chrono_literals;
27 
28 namespace android::net {
29 
30 namespace {
31 
32 // Dump the log to STDOUT and capture it.
33 std::string captureDumpOutput(const DnsQueryLog& queryLog) {
34     netdutils::DumpWriter dw(STDOUT_FILENO);
35     CapturedStdout captured;
36     queryLog.dump(dw);
37     return captured.str();
38 }
39 
40 // A simple check for the dump result by checking the netIds one by one.
41 void verifyDumpOutput(const std::string& dumpLog, const std::vector<int>& expectedNetIds) {
42     // Capture three matches: netId, hostname, and answer (empty allowed).
43     static const std::regex pattern(
44             R"(netId=(\d+).* hostname=([\w\*]+) answer=\[([\w:,\.\*\s]*)\])");
45 
46     std::string str(dumpLog);
47     std::smatch sm;
48     for (const auto& netId : expectedNetIds) {
49         SCOPED_TRACE(netId);
50         EXPECT_TRUE(std::regex_search(str, sm, pattern));
51         EXPECT_EQ(sm[1], std::to_string(netId));
52         str = sm.suffix();
53     }
54 
55     // Ensure the dumpLog is exactly as expected.
56     EXPECT_FALSE(std::regex_search(str, sm, pattern));
57 }
58 
59 }  // namespace
60 
61 class DnsQueryLogTest : public ::testing::Test {
62   protected:
63     const std::vector<std::string> serversV4 = {"127.0.0.1", "1.2.3.4"};
64     const std::vector<std::string> serversV4V6 = {"127.0.0.1", "1.2.3.4", "2001:db8::1",
65                                                   "fe80:1::2%testnet"};
66 };
67 
68 TEST_F(DnsQueryLogTest, Push) {
69     std::vector<DnsQueryLog::Record> records = {
70             DnsQueryLog::Record(30, 1000, 1000, "example.com", serversV4, 10),
71             DnsQueryLog::Record(31, 1000, 1000, "", serversV4, 10),      // Empty hostname.
72             DnsQueryLog::Record(32, 1000, 1000, "example.com", {}, 10),  // No answer.
73             DnsQueryLog::Record(33, 1000, 1000, "example.com", serversV4V6, 10),
74     };
75     DnsQueryLog queryLog;
76     for (auto& r : records) {
77         queryLog.push(std::move(r));
78     }
79 
80     std::string output = captureDumpOutput(queryLog);
81     verifyDumpOutput(output, {30, 31, 32, 33});
82 }
83 
84 TEST_F(DnsQueryLogTest, PushStressTest) {
85     const int threadNum = 100;
86     const int pushNum = 1000;
87     const size_t size = 500;
88     DnsQueryLog queryLog(size);
89     std::vector<std::thread> threads(threadNum);
90 
91     // Launch 'threadNum' threads to push the same queryLog 'pushNum' times.
92     for (auto& thread : threads) {
93         thread = std::thread([&]() {
94             for (int i = 0; i < pushNum; i++) {
95                 DnsQueryLog::Record record(30, 1000, 1000, "www.example.com", serversV4, 10);
96                 queryLog.push(std::move(record));
97             }
98         });
99     }
100     for (auto& thread : threads) {
101         thread.join();
102     }
103 
104     // Verify there are exact 'size' records in queryLog.
105     std::string output = captureDumpOutput(queryLog);
106     verifyDumpOutput(output, std::vector(size, 30));
107 }
108 
109 TEST_F(DnsQueryLogTest, ZeroSize) {
110     const size_t size = 0;
111     DnsQueryLog::Record r1(30, 1000, 1000, "www.example1.com", serversV4V6, 10);
112     DnsQueryLog::Record r2(31, 1000, 1000, "www.example2.com", serversV4V6, 10);
113     DnsQueryLog::Record r3(32, 1000, 1000, "www.example3.com", serversV4V6, 10);
114 
115     DnsQueryLog queryLog(size);
116     queryLog.push(std::move(r1));
117     queryLog.push(std::move(r2));
118     queryLog.push(std::move(r3));
119 
120     std::string output = captureDumpOutput(queryLog);
121     verifyDumpOutput(output, {});
122 }
123 
124 TEST_F(DnsQueryLogTest, CapacityFull) {
125     const size_t size = 3;
126     DnsQueryLog::Record r1(30, 1000, 1000, "www.example1.com", serversV4V6, 10);
127     DnsQueryLog::Record r2(31, 1000, 1000, "www.example2.com", serversV4V6, 10);
128     DnsQueryLog::Record r3(32, 1000, 1000, "www.example3.com", serversV4V6, 10);
129     DnsQueryLog::Record r4(33, 1000, 1000, "www.example4.com", serversV4V6, 10);
130     const std::vector<int> expectedNetIds = {31, 32, 33};
131 
132     DnsQueryLog queryLog(size);
133     queryLog.push(std::move(r1));
134     queryLog.push(std::move(r2));
135     queryLog.push(std::move(r3));
136     queryLog.push(std::move(r4));
137 
138     std::string output = captureDumpOutput(queryLog);
139     verifyDumpOutput(output, expectedNetIds);
140 }
141 
142 TEST_F(DnsQueryLogTest, ValidityTime) {
143     DnsQueryLog::Record r1(30, 1000, 1000, "www.example.com", serversV4, 10);
144     DnsQueryLog queryLog(3, 100ms);
145     queryLog.push(std::move(r1));
146 
147     // Dump the output and verify the correctness by checking netId.
148     std::string output = captureDumpOutput(queryLog);
149     verifyDumpOutput(output, {30});
150 
151     std::this_thread::sleep_for(150ms);
152 
153     // The record is expired thus not shown in the output.
154     output = captureDumpOutput(queryLog);
155     verifyDumpOutput(output, {});
156 
157     // Push another record to ensure it still works.
158     DnsQueryLog::Record r2(31, 1000, 1000, "example.com", serversV4V6, 10);
159     queryLog.push(std::move(r2));
160     output = captureDumpOutput(queryLog);
161     verifyDumpOutput(output, {31});
162 }
163 
164 }  // namespace android::net
165