1  // Copyright (c) 2011-2021 The Bitcoin Core developers
  2  // Distributed under the MIT software license, see the accompanying
  3  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  4  //
  5  
  6  #include <netaddress.h>
  7  #include <noui.h>
  8  #include <test/util/logging.h>
  9  #include <test/util/setup_common.h>
 10  #include <timedata.h>
 11  #include <util/string.h>
 12  #include <util/translation.h>
 13  #include <warnings.h>
 14  
 15  #include <string>
 16  
 17  #include <boost/test/unit_test.hpp>
 18  
 19  BOOST_FIXTURE_TEST_SUITE(timedata_tests, BasicTestingSetup)
 20  
 21  BOOST_AUTO_TEST_CASE(util_MedianFilter)
 22  {
 23      CMedianFilter<int> filter(5, 15);
 24  
 25      BOOST_CHECK_EQUAL(filter.median(), 15);
 26  
 27      filter.input(20); // [15 20]
 28      BOOST_CHECK_EQUAL(filter.median(), 17);
 29  
 30      filter.input(30); // [15 20 30]
 31      BOOST_CHECK_EQUAL(filter.median(), 20);
 32  
 33      filter.input(3); // [3 15 20 30]
 34      BOOST_CHECK_EQUAL(filter.median(), 17);
 35  
 36      filter.input(7); // [3 7 15 20 30]
 37      BOOST_CHECK_EQUAL(filter.median(), 15);
 38  
 39      filter.input(18); // [3 7 18 20 30]
 40      BOOST_CHECK_EQUAL(filter.median(), 18);
 41  
 42      filter.input(0); // [0 3 7 18 30]
 43      BOOST_CHECK_EQUAL(filter.median(), 7);
 44  }
 45  
 46  static void MultiAddTimeData(int n, int64_t offset)
 47  {
 48      static int cnt = 0;
 49      for (int i = 0; i < n; ++i) {
 50          CNetAddr addr;
 51          addr.SetInternal(ToString(++cnt));
 52          AddTimeData(addr, offset);
 53      }
 54  }
 55  
 56  
 57  BOOST_AUTO_TEST_CASE(addtimedata)
 58  {
 59      BOOST_CHECK_EQUAL(GetTimeOffset(), 0);
 60  
 61      //Part 1: Add large offsets to test a warning message that our clock may be wrong.
 62      MultiAddTimeData(3, DEFAULT_MAX_TIME_ADJUSTMENT + 1);
 63      // Filter size is 1 + 3 = 4: It is always initialized with a single element (offset 0)
 64  
 65      {
 66          ASSERT_DEBUG_LOG("Please check that your computer's date and time are correct!");
 67          MultiAddTimeData(1, DEFAULT_MAX_TIME_ADJUSTMENT + 1); //filter size 5
 68      }
 69  
 70      BOOST_CHECK(GetWarnings(true).original.find("clock is wrong") != std::string::npos);
 71  
 72      // nTimeOffset is not changed if the median of offsets exceeds DEFAULT_MAX_TIME_ADJUSTMENT
 73      BOOST_CHECK_EQUAL(GetTimeOffset(), 0);
 74  
 75      // Part 2: Test positive and negative medians by adding more offsets
 76      MultiAddTimeData(4, 100); // filter size 9
 77      BOOST_CHECK_EQUAL(GetTimeOffset(), 100);
 78      MultiAddTimeData(10, -100); //filter size 19
 79      BOOST_CHECK_EQUAL(GetTimeOffset(), -100);
 80  
 81      // Part 3: Test behaviour when filter has reached maximum number of offsets
 82      const int MAX_SAMPLES = 200;
 83      int nfill = (MAX_SAMPLES - 3 - 19) / 2; //89
 84      MultiAddTimeData(nfill, 100);
 85      MultiAddTimeData(nfill, -100); //filter size MAX_SAMPLES - 3
 86      BOOST_CHECK_EQUAL(GetTimeOffset(), -100);
 87  
 88      MultiAddTimeData(2, 100);
 89      //filter size MAX_SAMPLES -1, median is the initial 0 offset
 90      //since we added same number of positive/negative offsets
 91  
 92      BOOST_CHECK_EQUAL(GetTimeOffset(), 0);
 93  
 94      // After the number of offsets has reached MAX_SAMPLES -1 (=199), nTimeOffset will never change
 95      // because it is only updated when the number of elements in the filter becomes odd. It was decided
 96      // not to fix this because it prevents possible attacks. See the comment in AddTimeData() or issue #4521
 97      // for a more detailed explanation.
 98      MultiAddTimeData(2, 100); // filter median is 100 now, but nTimeOffset will not change
 99      // We want this test to end with nTimeOffset==0, otherwise subsequent tests of the suite will fail.
100      BOOST_CHECK_EQUAL(GetTimeOffset(), 0);
101  
102      TestOnlyResetTimeData();
103  }
104  
105  BOOST_AUTO_TEST_SUITE_END()