tcp-advertised-window-test.cc

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/*
 * Copyright (c) 2017 Christoph Doepmann <doepmanc@informatik.hu-berlin.de>
 *
 * 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/random-variable-stream.h"
#include "ns3/tcp-rx-buffer.h"
 
using namespace ns3;
 
NS_LOG_COMPONENT_DEFINE("TcpAdvertisedWindowTestSuite");
 
class TcpSocketAdvertisedWindowProxy : public TcpSocketMsgBase
{
  public:
    static TypeId GetTypeId();
 
    typedef Callback<void, uint16_t, uint16_t> InvalidAwndCallback;
 
    TcpSocketAdvertisedWindowProxy()
        : TcpSocketMsgBase(),
          m_segmentSize(0)
    {
    }
 
    TcpSocketAdvertisedWindowProxy(const TcpSocketAdvertisedWindowProxy& other)
        : TcpSocketMsgBase(other)
    {
        m_segmentSize = other.m_segmentSize;
        m_inwalidAwndCb = other.m_inwalidAwndCb;
    }
 
    void SetInvalidAwndCb(InvalidAwndCallback cb);
 
    void SetExpectedSegmentSize(uint16_t seg)
    {
        m_segmentSize = seg;
    };
 
  protected:
    Ptr<TcpSocketBase> Fork() override;
    uint16_t AdvertisedWindowSize(bool scale = true) const override;
 
  private:
    uint16_t OldAdvertisedWindowSize(bool scale = true) const;
    InvalidAwndCallback m_inwalidAwndCb; 
 
    uint16_t m_segmentSize;
};
 
void
TcpSocketAdvertisedWindowProxy::SetInvalidAwndCb(InvalidAwndCallback cb)
{
    NS_ASSERT(!cb.IsNull());
    m_inwalidAwndCb = cb;
}
 
TypeId
TcpSocketAdvertisedWindowProxy::GetTypeId()
{
    static TypeId tid = TypeId("ns3::TcpSocketAdvertisedWindowProxy")
                            .SetParent<TcpSocketMsgBase>()
                            .SetGroupName("Internet")
                            .AddConstructor<TcpSocketAdvertisedWindowProxy>();
    return tid;
}
 
Ptr<TcpSocketBase>
TcpSocketAdvertisedWindowProxy::Fork()
{
    return CopyObject<TcpSocketAdvertisedWindowProxy>(this);
}
 
uint16_t
TcpSocketAdvertisedWindowProxy::AdvertisedWindowSize(bool scale) const
{
    NS_LOG_FUNCTION(this << scale);
 
    uint16_t newAwnd = TcpSocketMsgBase::AdvertisedWindowSize(scale);
    uint16_t oldAwnd = OldAdvertisedWindowSize(scale);
 
    if (!m_tcb->m_rxBuffer->Finished())
    {
        // The calculated windows will only be exactly equal if there is no data
        // in the receive buffer yet.
        if (newAwnd != oldAwnd)
        {
            uint32_t available = m_tcb->m_rxBuffer->Available();
            // If the values differ, make sure this is only due to the single segment
            // the socket just got, which has not yet been read by the application.
            // Therefore, the difference should be exactly the size of one segment
            // (but taking scale and m_maxWinSize into account).
            uint32_t newAwndKnownDifference = newAwnd;
            if (scale)
            {
                newAwndKnownDifference += (available >> m_rcvWindShift);
            }
            else
            {
                newAwndKnownDifference += available;
            }
 
            if (newAwndKnownDifference > m_maxWinSize)
            {
                newAwndKnownDifference = m_maxWinSize;
            }
 
            if (static_cast<uint16_t>(newAwndKnownDifference) != oldAwnd)
            {
                if (!m_inwalidAwndCb.IsNull())
                {
                    m_inwalidAwndCb(oldAwnd, newAwnd);
                }
            }
        }
    }
 
    return newAwnd;
}
 
uint16_t
TcpSocketAdvertisedWindowProxy::OldAdvertisedWindowSize(bool scale) const
{
    NS_LOG_FUNCTION(this << scale);
    // NS_LOG_DEBUG ("MaxRxSequence () = " << m_tcb->m_rxBuffer->MaxRxSequence ());
    // NS_LOG_DEBUG ("NextRxSequence () = " << m_tcb->m_rxBuffer->NextRxSequence ());
    // NS_LOG_DEBUG ("MaxBufferSize () = " << m_tcb->m_rxBuffer->MaxBufferSize ());
    // NS_LOG_DEBUG ("m_rcvWindShift = " << static_cast<uint16_t> (m_rcvWindShift));
    // NS_LOG_DEBUG ("m_maxWinSize = " << m_maxWinSize);
    // NS_LOG_DEBUG ("Available () = " << m_tcb->m_rxBuffer->Available ());
    uint32_t w = m_tcb->m_rxBuffer->MaxBufferSize();
 
    if (scale)
    {
        w >>= m_rcvWindShift;
    }
    if (w > m_maxWinSize)
    {
        w = m_maxWinSize;
        NS_LOG_WARN("Adv window size truncated to "
                    << m_maxWinSize << "; possibly to avoid overflow of the 16-bit integer");
    }
    NS_LOG_DEBUG("Returning AdvertisedWindowSize of " << static_cast<uint16_t>(w));
    return static_cast<uint16_t>(w);
}
 
NS_OBJECT_ENSURE_REGISTERED(TcpSocketAdvertisedWindowProxy);
 
class TcpDropRatioErrorModel : public TcpGeneralErrorModel
{
  public:
    static TypeId GetTypeId();
 
    TcpDropRatioErrorModel(double dropRatio)
        : TcpGeneralErrorModel(),
          m_dropRatio(dropRatio)
    {
        m_prng = CreateObject<UniformRandomVariable>();
    }
 
  protected:
    bool ShouldDrop(const Ipv4Header& ipHeader,
                    const TcpHeader& tcpHeader,
                    uint32_t packetSize) override;
 
  private:
    void DoReset() override{};
    double m_dropRatio;                
    Ptr<UniformRandomVariable> m_prng; 
};
 
NS_OBJECT_ENSURE_REGISTERED(TcpDropRatioErrorModel);
 
TypeId
TcpDropRatioErrorModel::GetTypeId()
{
    static TypeId tid = TypeId("ns3::TcpDropRatioErrorModel").SetParent<TcpGeneralErrorModel>();
    return tid;
}
 
bool
TcpDropRatioErrorModel::ShouldDrop(const Ipv4Header& ipHeader,
                                   const TcpHeader& tcpHeader,
                                   uint32_t packetSize)
{
    return m_prng->GetValue() < m_dropRatio;
}
 
class TcpAdvertisedWindowTest : public TcpGeneralTest
{
  public:
    TcpAdvertisedWindowTest(const std::string& desc,
                            uint32_t size,
                            uint32_t packets,
                            double lossRatio);
 
  protected:
    void ConfigureEnvironment() override;
    Ptr<TcpSocketMsgBase> CreateReceiverSocket(Ptr<Node> node) override;
    Ptr<ErrorModel> CreateReceiverErrorModel() override;
 
  private:
    void InvalidAwndCb(uint16_t oldAwnd, uint16_t newAwnd);
    uint32_t m_pktSize;  
    uint32_t m_pktCount; 
    double m_lossRatio;  
};
 
TcpAdvertisedWindowTest::TcpAdvertisedWindowTest(const std::string& desc,
                                                 uint32_t size,
                                                 uint32_t packets,
                                                 double lossRatio)
    : TcpGeneralTest(desc),
      m_pktSize(size),
      m_pktCount(packets),
      m_lossRatio(lossRatio)
{
}
 
void
TcpAdvertisedWindowTest::ConfigureEnvironment()
{
    TcpGeneralTest::ConfigureEnvironment();
    SetAppPktCount(m_pktCount);
    SetPropagationDelay(MilliSeconds(50));
    SetTransmitStart(Seconds(2.0));
    SetAppPktSize(m_pktSize);
}
 
Ptr<TcpSocketMsgBase>
TcpAdvertisedWindowTest::CreateReceiverSocket(Ptr<Node> node)
{
    NS_LOG_FUNCTION(this);
 
    Ptr<TcpSocketMsgBase> sock =
        CreateSocket(node, TcpSocketAdvertisedWindowProxy::GetTypeId(), m_congControlTypeId);
    DynamicCast<TcpSocketAdvertisedWindowProxy>(sock)->SetExpectedSegmentSize(500);
    DynamicCast<TcpSocketAdvertisedWindowProxy>(sock)->SetInvalidAwndCb(
        MakeCallback(&TcpAdvertisedWindowTest::InvalidAwndCb, this));
 
    return sock;
}
 
Ptr<ErrorModel>
TcpAdvertisedWindowTest::CreateReceiverErrorModel()
{
    return CreateObject<TcpDropRatioErrorModel>(m_lossRatio);
}
 
void
TcpAdvertisedWindowTest::InvalidAwndCb(uint16_t oldAwnd, uint16_t newAwnd)
{
    NS_TEST_ASSERT_MSG_EQ(oldAwnd, newAwnd, "Old and new AWND calculations do not match.");
}
 
//-----------------------------------------------------------------------------
 
class TcpAdvWindowOnLossTest : public TcpGeneralTest
{
  public:
    TcpAdvWindowOnLossTest(const std::string& desc,
                           uint32_t size,
                           uint32_t packets,
                           std::vector<uint32_t>& toDrop);
 
  protected:
    void ConfigureEnvironment() override;
    Ptr<TcpSocketMsgBase> CreateReceiverSocket(Ptr<Node> node) override;
    Ptr<TcpSocketMsgBase> CreateSenderSocket(Ptr<Node> node) override;
    Ptr<ErrorModel> CreateReceiverErrorModel() override;
 
  private:
    void InvalidAwndCb(uint16_t oldAwnd, uint16_t newAwnd);
    uint32_t m_pktSize;             
    uint32_t m_pktCount;            
    std::vector<uint32_t> m_toDrop; 
};
 
TcpAdvWindowOnLossTest::TcpAdvWindowOnLossTest(const std::string& desc,
                                               uint32_t size,
                                               uint32_t packets,
                                               std::vector<uint32_t>& toDrop)
    : TcpGeneralTest(desc),
      m_pktSize(size),
      m_pktCount(packets),
      m_toDrop(toDrop)
{
}
 
void
TcpAdvWindowOnLossTest::ConfigureEnvironment()
{
    TcpGeneralTest::ConfigureEnvironment();
    SetAppPktCount(m_pktCount);
    SetPropagationDelay(MilliSeconds(50));
    SetTransmitStart(Seconds(2.0));
    SetAppPktSize(m_pktSize);
}
 
Ptr<TcpSocketMsgBase>
TcpAdvWindowOnLossTest::CreateReceiverSocket(Ptr<Node> node)
{
    NS_LOG_FUNCTION(this);
 
    Ptr<TcpSocketMsgBase> sock =
        CreateSocket(node, TcpSocketAdvertisedWindowProxy::GetTypeId(), m_congControlTypeId);
    DynamicCast<TcpSocketAdvertisedWindowProxy>(sock)->SetExpectedSegmentSize(500);
    DynamicCast<TcpSocketAdvertisedWindowProxy>(sock)->SetInvalidAwndCb(
        MakeCallback(&TcpAdvWindowOnLossTest::InvalidAwndCb, this));
 
    return sock;
}
 
Ptr<TcpSocketMsgBase>
TcpAdvWindowOnLossTest::CreateSenderSocket(Ptr<Node> node)
{
    auto socket = TcpGeneralTest::CreateSenderSocket(node);
    socket->SetAttribute("InitialCwnd", UintegerValue(10 * m_pktSize));
 
    return socket;
}
 
Ptr<ErrorModel>
TcpAdvWindowOnLossTest::CreateReceiverErrorModel()
{
    Ptr<TcpSeqErrorModel> m_errorModel = CreateObject<TcpSeqErrorModel>();
    for (std::vector<uint32_t>::iterator it = m_toDrop.begin(); it != m_toDrop.end(); ++it)
    {
        m_errorModel->AddSeqToKill(SequenceNumber32(*it));
    }
 
    return m_errorModel;
}
 
void
TcpAdvWindowOnLossTest::InvalidAwndCb(uint16_t oldAwnd, uint16_t newAwnd)
{
    NS_TEST_ASSERT_MSG_EQ(oldAwnd, newAwnd, "Old and new AWND calculations do not match.");
}
 
//-----------------------------------------------------------------------------
 
class TcpAdvertisedWindowTestSuite : public TestSuite
{
  public:
    TcpAdvertisedWindowTestSuite()
        : TestSuite("tcp-advertised-window-test", UNIT)
    {
        AddTestCase(new TcpAdvertisedWindowTest("TCP advertised window size, small seg + no loss",
                                                500,
                                                100,
                                                0.0),
                    TestCase::QUICK);
        AddTestCase(new TcpAdvertisedWindowTest("TCP advertised window size, small seg + loss",
                                                500,
                                                100,
                                                0.1),
                    TestCase::QUICK);
        AddTestCase(new TcpAdvertisedWindowTest("TCP advertised window size, large seg + no loss",
                                                1000,
                                                100,
                                                0.0),
                    TestCase::QUICK);
        AddTestCase(
            new TcpAdvertisedWindowTest("TCP advertised window size, large seg + small loss",
                                        1000,
                                        100,
                                        0.1),
            TestCase::QUICK);
        AddTestCase(new TcpAdvertisedWindowTest("TCP advertised window size, large seg + big loss",
                                                1000,
                                                100,
                                                0.3),
                    TestCase::QUICK);
        AddTestCase(new TcpAdvertisedWindowTest("TCP advertised window size, complete loss",
                                                1000,
                                                100,
                                                1.0),
                    TestCase::QUICK);
 
        std::vector<uint32_t> toDrop;
        toDrop.push_back(8001);
        toDrop.push_back(9001);
        AddTestCase(new TcpAdvWindowOnLossTest("TCP advertised window size, after FIN loss",
                                               1000,
                                               10,
                                               toDrop));
    }
};
 
static TcpAdvertisedWindowTestSuite
    g_tcpAdvertisedWindowTestSuite; //<! static obj for test initialization