tcp-rtt-estimation.cc

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/*
 * Copyright (c) 2016 Natale Patriciello <natale.patriciello@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
 
#include "tcp-error-model.h"
#include "tcp-general-test.h"
 
#include "ns3/log.h"
#include "ns3/node.h"
#include "ns3/rtt-estimator.h"
 
using namespace ns3;
 
NS_LOG_COMPONENT_DEFINE("TcpRttEstimationTestSuite");
 
class TcpRttEstimationTest : public TcpGeneralTest
{
  public:
    TcpRttEstimationTest(const std::string& desc, bool enableTs, uint32_t pktCount);
 
  protected:
    Ptr<TcpSocketMsgBase> CreateReceiverSocket(Ptr<Node> node) override;
    Ptr<TcpSocketMsgBase> CreateSenderSocket(Ptr<Node> node) override;
 
    void Rx(const Ptr<const Packet> p, const TcpHeader& h, SocketWho who) override;
    void Tx(const Ptr<const Packet> p, const TcpHeader& h, SocketWho who) override;
    void UpdatedRttHistory(const SequenceNumber32& seq,
                           uint32_t sz,
                           bool isRetransmission,
                           SocketWho who) override;
    void RttTrace(Time oldTime, Time newTime) override;
    void FinalChecks() override;
 
    void ConfigureEnvironment() override;
 
  private:
    bool m_enableTs;                 
    bool m_rttChanged;               
    SequenceNumber32 m_highestTxSeq; 
    uint32_t m_pktCount;             
    uint32_t m_dataCount;            
};
 
TcpRttEstimationTest::TcpRttEstimationTest(const std::string& desc,
                                           bool enableTs,
                                           uint32_t pktCount)
    : TcpGeneralTest(desc),
      m_enableTs(enableTs),
      m_rttChanged(false),
      m_highestTxSeq(0),
      m_pktCount(pktCount),
      m_dataCount(0)
{
}
 
void
TcpRttEstimationTest::ConfigureEnvironment()
{
    TcpGeneralTest::ConfigureEnvironment();
    SetAppPktCount(m_pktCount);
    SetPropagationDelay(MilliSeconds(50));
    SetTransmitStart(Seconds(2.0));
    SetMTU(500);
}
 
Ptr<TcpSocketMsgBase>
TcpRttEstimationTest::CreateReceiverSocket(Ptr<Node> node)
{
    Ptr<TcpSocketMsgBase> s = TcpGeneralTest::CreateReceiverSocket(node);
    if (!m_enableTs)
    {
        s->SetAttribute("Timestamp", BooleanValue(false));
    }
 
    return s;
}
 
Ptr<TcpSocketMsgBase>
TcpRttEstimationTest::CreateSenderSocket(Ptr<Node> node)
{
    Ptr<TcpSocketMsgBase> s = TcpGeneralTest::CreateSenderSocket(node);
    if (!m_enableTs)
    {
        s->SetAttribute("Timestamp", BooleanValue(false));
    }
 
    return s;
}
 
void
TcpRttEstimationTest::Tx(const Ptr<const Packet> p, const TcpHeader& h, SocketWho who)
{
    if (who == SENDER && h.GetFlags() != TcpHeader::SYN)
    {
        if (m_highestTxSeq < h.GetSequenceNumber())
        {
            m_highestTxSeq = h.GetSequenceNumber();
            m_dataCount = 0;
        }
 
        Ptr<RttEstimator> rttEstimator = GetRttEstimator(SENDER);
        NS_TEST_ASSERT_MSG_NE(rttEstimator,
                              nullptr,
                              "rtt is 0 (and should be different from zero)");
        NS_LOG_DEBUG("S Tx: seq=" << h.GetSequenceNumber() << " ack=" << h.GetAckNumber());
        NS_TEST_ASSERT_MSG_NE(rttEstimator->GetEstimate(),
                              Seconds(1),
                              "Default Estimate for the RTT");
    }
}
 
void
TcpRttEstimationTest::Rx(const Ptr<const Packet> p, const TcpHeader& h, SocketWho who)
{
    if (who == RECEIVER)
    {
        NS_LOG_DEBUG("R Rx: seq=" << h.GetSequenceNumber() << " ack=" << h.GetAckNumber());
    }
}
 
void
TcpRttEstimationTest::UpdatedRttHistory(const SequenceNumber32& seq,
                                        uint32_t sz,
                                        bool isRetransmission,
                                        SocketWho who)
{
    if (sz == 0)
    {
        return;
    }
 
    if (seq < m_highestTxSeq)
    {
        NS_TEST_ASSERT_MSG_EQ(isRetransmission, true, "A retransmission is not flagged as such");
    }
    else if (seq == m_highestTxSeq && m_dataCount == 0)
    {
        NS_TEST_ASSERT_MSG_EQ(isRetransmission,
                              false,
                              "Incorrectly flagging seq as retransmission");
        m_dataCount++;
    }
    else if (seq == m_highestTxSeq && m_dataCount > 0)
    {
        NS_TEST_ASSERT_MSG_EQ(isRetransmission, true, "A retransmission is not flagged as such");
    }
}
 
void
TcpRttEstimationTest::RttTrace(Time oldTime, Time newTime)
{
    NS_LOG_DEBUG("Rtt changed to " << newTime.GetSeconds());
    m_rttChanged = true;
}
 
void
TcpRttEstimationTest::FinalChecks()
{
    NS_TEST_ASSERT_MSG_EQ(m_rttChanged, true, "Rtt was not updated");
}
 
class TcpRttEstimationWithLossTest : public TcpRttEstimationTest
{
  public:
    TcpRttEstimationWithLossTest(const std::string& desc,
                                 bool enableTs,
                                 uint32_t pktCount,
                                 std::vector<uint32_t> toDrop);
 
  protected:
    Ptr<ErrorModel> CreateReceiverErrorModel() override;
 
  private:
    std::vector<uint32_t> m_toDrop; 
};
 
TcpRttEstimationWithLossTest::TcpRttEstimationWithLossTest(const std::string& desc,
                                                           bool enableTs,
                                                           uint32_t pktCount,
                                                           std::vector<uint32_t> toDrop)
    : TcpRttEstimationTest(desc, enableTs, pktCount),
      m_toDrop(toDrop)
{
}
 
Ptr<ErrorModel>
TcpRttEstimationWithLossTest::CreateReceiverErrorModel()
{
    Ptr<TcpSeqErrorModel> errorModel = CreateObject<TcpSeqErrorModel>();
 
    for (auto it = m_toDrop.begin(); it != m_toDrop.end(); ++it)
    {
        errorModel->AddSeqToKill(SequenceNumber32(*it));
    }
 
    return errorModel;
}
 
class TcpRttEstimationTestSuite : public TestSuite
{
  public:
    TcpRttEstimationTestSuite()
        : TestSuite("tcp-rtt-estimation-test", UNIT)
    {
        AddTestCase(new TcpRttEstimationTest("RTT estimation, ts, no data", true, 0),
                    TestCase::QUICK);
        AddTestCase(new TcpRttEstimationTest("RTT estimation, no ts, no data", false, 0),
                    TestCase::QUICK);
        AddTestCase(new TcpRttEstimationTest("RTT estimation, ts, some data", true, 10),
                    TestCase::QUICK);
        AddTestCase(new TcpRttEstimationTest("RTT estimation, no ts, some data", false, 10),
                    TestCase::QUICK);
 
        std::vector<uint32_t> toDrop;
        toDrop.push_back(501);
 
        AddTestCase(new TcpRttEstimationWithLossTest("RTT estimation, no ts,"
                                                     " some data, with retr",
                                                     false,
                                                     10,
                                                     toDrop),
                    TestCase::QUICK);
        AddTestCase(new TcpRttEstimationWithLossTest("RTT estimation, ts,"
                                                     " some data, with retr",
                                                     true,
                                                     10,
                                                     toDrop),
                    TestCase::QUICK);
 
        toDrop.push_back(501);
        AddTestCase(new TcpRttEstimationWithLossTest("RTT estimation, no ts,"
                                                     " some data, with retr",
                                                     false,
                                                     10,
                                                     toDrop),
                    TestCase::QUICK);
        AddTestCase(new TcpRttEstimationWithLossTest("RTT estimation, ts,"
                                                     " some data, with retr",
                                                     true,
                                                     10,
                                                     toDrop),
                    TestCase::QUICK);
 
        toDrop.push_back(54001);
        toDrop.push_back(58001);
        toDrop.push_back(58501);
        toDrop.push_back(60001);
        toDrop.push_back(68501);
        AddTestCase(new TcpRttEstimationWithLossTest("RTT estimation, no ts,"
                                                     " a lot of data, with retr",
                                                     false,
                                                     1000,
                                                     toDrop),
                    TestCase::QUICK);
        AddTestCase(new TcpRttEstimationWithLossTest("RTT estimation, ts,"
                                                     " a lot of data, with retr",
                                                     true,
                                                     1000,
                                                     toDrop),
                    TestCase::QUICK);
    }
};
 
static TcpRttEstimationTestSuite
    g_tcpRttEstimationTestSuite;