wifi-psdu.cc

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/*
 * Copyright (c) 2019 Universita' degli Studi di Napoli Federico II
 *
 * 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
 *
 * Author: Stefano Avallone <stavallo@unina.it>
 */
 
#include "wifi-psdu.h"
 
#include "ampdu-subframe-header.h"
#include "mpdu-aggregator.h"
#include "wifi-mac-trailer.h"
#include "wifi-utils.h"
 
#include "ns3/log.h"
#include "ns3/packet.h"
 
namespace ns3
{
 
NS_LOG_COMPONENT_DEFINE("WifiPsdu");
 
WifiPsdu::WifiPsdu(Ptr<const Packet> p, const WifiMacHeader& header)
    : m_isSingle(false)
{
    m_mpduList.push_back(Create<WifiMpdu>(p, header));
    m_size = header.GetSerializedSize() + p->GetSize() + WIFI_MAC_FCS_LENGTH;
}
 
WifiPsdu::WifiPsdu(Ptr<WifiMpdu> mpdu, bool isSingle)
    : m_isSingle(isSingle)
{
    m_mpduList.push_back(mpdu);
    m_size = mpdu->GetSize();
 
    if (isSingle)
    {
        m_size += 4; // A-MPDU Subframe header size
    }
}
 
WifiPsdu::WifiPsdu(Ptr<const WifiMpdu> mpdu, bool isSingle)
    : WifiPsdu(Create<WifiMpdu>(*mpdu), isSingle)
{
}
 
WifiPsdu::WifiPsdu(std::vector<Ptr<WifiMpdu>> mpduList)
    : m_isSingle(mpduList.size() == 1),
      m_mpduList(mpduList)
{
    NS_ABORT_MSG_IF(mpduList.empty(), "Cannot initialize a WifiPsdu with an empty MPDU list");
 
    m_size = 0;
    for (auto& mpdu : m_mpduList)
    {
        m_size = MpduAggregator::GetSizeIfAggregated(mpdu->GetSize(), m_size);
    }
}
 
WifiPsdu::~WifiPsdu()
{
}
 
bool
WifiPsdu::IsSingle() const
{
    return m_isSingle;
}
 
bool
WifiPsdu::IsAggregate() const
{
    return (m_mpduList.size() > 1 || m_isSingle);
}
 
Ptr<const Packet>
WifiPsdu::GetPacket() const
{
    Ptr<Packet> packet = Create<Packet>();
    if (m_mpduList.size() == 1 && !m_isSingle)
    {
        packet = m_mpduList.at(0)->GetPacket()->Copy();
        packet->AddHeader(m_mpduList.at(0)->GetHeader());
        AddWifiMacTrailer(packet);
    }
    else if (m_isSingle)
    {
        MpduAggregator::Aggregate(m_mpduList.at(0), packet, true);
    }
    else
    {
        for (auto& mpdu : m_mpduList)
        {
            MpduAggregator::Aggregate(mpdu, packet, false);
        }
    }
    return packet;
}
 
Mac48Address
WifiPsdu::GetAddr1() const
{
    Mac48Address ra = m_mpduList.at(0)->GetHeader().GetAddr1();
    // check that the other MPDUs have the same RA
    for (std::size_t i = 1; i < m_mpduList.size(); i++)
    {
        if (m_mpduList.at(i)->GetHeader().GetAddr1() != ra)
        {
            NS_ABORT_MSG("MPDUs in an A-AMPDU must have the same receiver address");
        }
    }
    return ra;
}
 
Mac48Address
WifiPsdu::GetAddr2() const
{
    Mac48Address ta = m_mpduList.at(0)->GetHeader().GetAddr2();
    // check that the other MPDUs have the same TA
    for (std::size_t i = 1; i < m_mpduList.size(); i++)
    {
        if (m_mpduList.at(i)->GetHeader().GetAddr2() != ta)
        {
            NS_ABORT_MSG("MPDUs in an A-AMPDU must have the same transmitter address");
        }
    }
    return ta;
}
 
bool
WifiPsdu::HasNav() const
{
    // When the contents of a received Duration/ID field, treated as an unsigned integer,
    // are greater than 32 768, the contents are interpreted as appropriate for the frame
    // type and subtype or ignored if the receiving MAC entity does not have a defined
    // interpretation for that type and subtype (IEEE 802.11-2016 sec. 10.27.3)
    return (m_mpduList.at(0)->GetHeader().GetRawDuration() & 0x8000) == 0;
}
 
Time
WifiPsdu::GetDuration() const
{
    Time duration = m_mpduList.at(0)->GetHeader().GetDuration();
    // check that the other MPDUs have the same Duration/ID
    for (std::size_t i = 1; i < m_mpduList.size(); i++)
    {
        if (m_mpduList.at(i)->GetHeader().GetDuration() != duration)
        {
            NS_ABORT_MSG("MPDUs in an A-AMPDU must have the same Duration/ID");
        }
    }
    return duration;
}
 
void
WifiPsdu::SetDuration(Time duration)
{
    NS_LOG_FUNCTION(this << duration);
    for (auto& mpdu : m_mpduList)
    {
        mpdu->GetHeader().SetDuration(duration);
    }
}
 
std::set<uint8_t>
WifiPsdu::GetTids() const
{
    std::set<uint8_t> s;
    for (auto& mpdu : m_mpduList)
    {
        if (mpdu->GetHeader().IsQosData())
        {
            s.insert(mpdu->GetHeader().GetQosTid());
        }
    }
    return s;
}
 
WifiMacHeader::QosAckPolicy
WifiPsdu::GetAckPolicyForTid(uint8_t tid) const
{
    NS_LOG_FUNCTION(this << +tid);
    WifiMacHeader::QosAckPolicy policy;
    auto it = m_mpduList.begin();
    bool found = false;
 
    // find the first QoS Data frame with the given TID
    do
    {
        if ((*it)->GetHeader().IsQosData() && (*it)->GetHeader().GetQosTid() == tid)
        {
            policy = (*it)->GetHeader().GetQosAckPolicy();
            found = true;
        }
        it++;
    } while (!found && it != m_mpduList.end());
 
    NS_ABORT_MSG_IF(!found, "No QoS Data frame in the PSDU");
 
    // check that the other QoS Data frames with the given TID have the same ack policy
    while (it != m_mpduList.end())
    {
        if ((*it)->GetHeader().IsQosData() && (*it)->GetHeader().GetQosTid() == tid &&
            (*it)->GetHeader().GetQosAckPolicy() != policy)
        {
            NS_ABORT_MSG("QoS Data frames with the same TID must have the same QoS Ack Policy");
        }
        it++;
    }
    return policy;
}
 
void
WifiPsdu::SetAckPolicyForTid(uint8_t tid, WifiMacHeader::QosAckPolicy policy)
{
    NS_LOG_FUNCTION(this << +tid << policy);
    for (auto& mpdu : m_mpduList)
    {
        if (mpdu->GetHeader().IsQosData() && mpdu->GetHeader().GetQosTid() == tid)
        {
            mpdu->GetHeader().SetQosAckPolicy(policy);
        }
    }
}
 
uint16_t
WifiPsdu::GetMaxDistFromStartingSeq(uint16_t startingSeq) const
{
    NS_LOG_FUNCTION(this << startingSeq);
 
    uint16_t maxDistFromStartingSeq = 0;
    bool foundFirst = false;
 
    for (auto& mpdu : m_mpduList)
    {
        uint16_t currSeqNum = mpdu->GetHeader().GetSequenceNumber();
 
        if (mpdu->GetHeader().IsQosData() && !QosUtilsIsOldPacket(startingSeq, currSeqNum))
        {
            uint16_t currDistToStartingSeq =
                (currSeqNum - startingSeq + SEQNO_SPACE_SIZE) % SEQNO_SPACE_SIZE;
 
            if (!foundFirst || currDistToStartingSeq > maxDistFromStartingSeq)
            {
                foundFirst = true;
                maxDistFromStartingSeq = currDistToStartingSeq;
            }
        }
    }
 
    if (!foundFirst)
    {
        NS_LOG_DEBUG("All QoS Data frames in this PSDU are old frames");
        return SEQNO_SPACE_SIZE;
    }
    NS_LOG_DEBUG("Returning " << maxDistFromStartingSeq);
    return maxDistFromStartingSeq;
}
 
uint32_t
WifiPsdu::GetSize() const
{
    return m_size;
}
 
const WifiMacHeader&
WifiPsdu::GetHeader(std::size_t i) const
{
    return m_mpduList.at(i)->GetHeader();
}
 
WifiMacHeader&
WifiPsdu::GetHeader(std::size_t i)
{
    return m_mpduList.at(i)->GetHeader();
}
 
Ptr<const Packet>
WifiPsdu::GetPayload(std::size_t i) const
{
    return m_mpduList.at(i)->GetPacket();
}
 
Ptr<Packet>
WifiPsdu::GetAmpduSubframe(std::size_t i) const
{
    NS_ASSERT(i < m_mpduList.size());
    Ptr<Packet> subframe = m_mpduList.at(i)->GetProtocolDataUnit();
    subframe->AddHeader(
        MpduAggregator::GetAmpduSubframeHeader(static_cast<uint16_t>(subframe->GetSize()),
                                               m_isSingle));
    size_t padding = GetAmpduSubframeSize(i) - subframe->GetSize();
    if (padding > 0)
    {
        Ptr<Packet> pad = Create<Packet>(padding);
        subframe->AddAtEnd(pad);
    }
    return subframe;
}
 
std::size_t
WifiPsdu::GetAmpduSubframeSize(std::size_t i) const
{
    NS_ASSERT(i < m_mpduList.size());
    size_t subframeSize = 4; // A-MPDU Subframe header size
    subframeSize += m_mpduList.at(i)->GetSize();
    if (i != m_mpduList.size() - 1) // add padding if not last
    {
        subframeSize += MpduAggregator::CalculatePadding(subframeSize);
    }
    return subframeSize;
}
 
std::size_t
WifiPsdu::GetNMpdus() const
{
    return m_mpduList.size();
}
 
std::vector<Ptr<WifiMpdu>>::const_iterator
WifiPsdu::begin() const
{
    return m_mpduList.begin();
}
 
std::vector<Ptr<WifiMpdu>>::iterator
WifiPsdu::begin()
{
    return m_mpduList.begin();
}
 
std::vector<Ptr<WifiMpdu>>::const_iterator
WifiPsdu::end() const
{
    return m_mpduList.end();
}
 
std::vector<Ptr<WifiMpdu>>::iterator
WifiPsdu::end()
{
    return m_mpduList.end();
}
 
void
WifiPsdu::Print(std::ostream& os) const
{
    os << "size=" << m_size;
    if (IsAggregate())
    {
        os << ", A-MPDU of " << GetNMpdus() << " MPDUs";
        for (const auto& mpdu : m_mpduList)
        {
            os << " (" << *mpdu << ")";
        }
    }
    else
    {
        os << ", " << ((m_isSingle) ? "S-MPDU" : "normal MPDU") << " (" << *(m_mpduList.at(0))
           << ")";
    }
}
 
std::ostream&
operator<<(std::ostream& os, const WifiPsdu& psdu)
{
    psdu.Print(os);
    return os;
}
 
} // namespace ns3