/*
 * Copyright (c) 2009 IITP RAS
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Authors: Kirill Andreev <andreev@iitp.ru>
 *          Aleksey Kovalenko <kovalenko@iitp.ru>
 *          Pavel Boyko <boyko@iitp.ru>
 */

#include "peer-link.h"

#include "peer-management-protocol-mac.h"

#include "ns3/log.h"
#include "ns3/simulator.h"
#include "ns3/traced-value.h"

namespace ns3
{

NS_LOG_COMPONENT_DEFINE("Dot11sPeerManagementProtocol");

namespace dot11s
{

NS_OBJECT_ENSURE_REGISTERED(PeerLink);

TypeId
PeerLink::GetTypeId()
{
    static TypeId tid =
        TypeId("ns3::dot11s::PeerLink")
            .SetParent<Object>()
            .SetGroupName("Mesh")
            .AddConstructor<PeerLink>()
            .AddAttribute("RetryTimeout",
                          "Retry timeout",
                          TimeValue(TimeValue(MicroSeconds(40 * 1024))),
                          MakeTimeAccessor(&PeerLink::m_dot11MeshRetryTimeout),
                          MakeTimeChecker())
            .AddAttribute("HoldingTimeout",
                          "Holding timeout",
                          TimeValue(TimeValue(MicroSeconds(40 * 1024))),
                          MakeTimeAccessor(&PeerLink::m_dot11MeshHoldingTimeout),
                          MakeTimeChecker())
            .AddAttribute("ConfirmTimeout",
                          "Confirm timeout",
                          TimeValue(TimeValue(MicroSeconds(40 * 1024))),
                          MakeTimeAccessor(&PeerLink::m_dot11MeshConfirmTimeout),
                          MakeTimeChecker())
            .AddAttribute("MaxRetries",
                          "Maximum number of retries",
                          UintegerValue(4),
                          MakeUintegerAccessor(&PeerLink::m_dot11MeshMaxRetries),
                          MakeUintegerChecker<uint16_t>())
            .AddAttribute("MaxBeaconLoss",
                          "Maximum number of lost beacons before link will be closed",
                          UintegerValue(2),
                          MakeUintegerAccessor(&PeerLink::m_maxBeaconLoss),
                          MakeUintegerChecker<uint16_t>(1))
            .AddAttribute("MaxPacketFailure",
                          "Maximum number of failed packets before link will be closed",
                          UintegerValue(2),
                          MakeUintegerAccessor(&PeerLink::m_maxPacketFail),
                          MakeUintegerChecker<uint16_t>(1));
    return tid;
}

const char* const PeerLink::PeerStateNames[6] =
    {"IDLE", "OPN_SNT", "CNF_RCVD", "OPN_RCVD", "ESTAB", "HOLDING"};

//-----------------------------------------------------------------------------
// PeerLink public interface
//-----------------------------------------------------------------------------
PeerLink::PeerLink()
    : m_peerAddress(Mac48Address::GetBroadcast()),
      m_peerMeshPointAddress(Mac48Address::GetBroadcast()),
      m_localLinkId(0),
      m_peerLinkId(0),
      m_assocId(0),
      m_peerAssocId(0),
      m_lastBeacon(Seconds(0)),
      m_beaconInterval(Seconds(0)),
      m_packetFail(0),
      m_state(IDLE),
      m_retryCounter(0),
      m_maxPacketFail(3)
{
    NS_LOG_FUNCTION(this);
}

PeerLink::~PeerLink()
{
}

void
PeerLink::DoDispose()
{
    NS_LOG_FUNCTION(this);
    m_retryTimer.Cancel();
    m_holdingTimer.Cancel();
    m_confirmTimer.Cancel();
    m_beaconLossTimer.Cancel();
    m_beaconTiming.ClearTimingElement();
}

void
PeerLink::SetPeerAddress(Mac48Address macaddr)
{
    m_peerAddress = macaddr;
}

void
PeerLink::SetPeerMeshPointAddress(Mac48Address macaddr)
{
    m_peerMeshPointAddress = macaddr;
}

void
PeerLink::SetInterface(uint32_t interface)
{
    m_interface = interface;
}

void
PeerLink::SetLocalLinkId(uint16_t id)
{
    m_localLinkId = id;
}

void
PeerLink::SetLocalAid(uint16_t aid)
{
    m_assocId = aid;
}

void
PeerLink::SetBeaconInformation(Time lastBeacon, Time beaconInterval)
{
    m_lastBeacon = lastBeacon;
    m_beaconInterval = beaconInterval;
    m_beaconLossTimer.Cancel();
    Time delay = Seconds(beaconInterval.GetSeconds() * m_maxBeaconLoss);
    NS_ASSERT(delay.GetMicroSeconds() != 0);
    m_beaconLossTimer = Simulator::Schedule(delay, &PeerLink::BeaconLoss, this);
}

void
PeerLink::MLMESetSignalStatusCallback(PeerLink::SignalStatusCallback cb)
{
    m_linkStatusCallback = cb;
}

void
PeerLink::BeaconLoss()
{
    NS_LOG_FUNCTION(this);
    StateMachine(CNCL);
}

void
PeerLink::TransmissionSuccess()
{
    m_packetFail = 0;
}

void
PeerLink::TransmissionFailure()
{
    NS_LOG_FUNCTION(this);
    m_packetFail++;
    if (m_packetFail == m_maxPacketFail)
    {
        NS_LOG_DEBUG("TransmissionFailure:: CNCL");
        StateMachine(CNCL);
        m_packetFail = 0;
    }
}

void
PeerLink::SetBeaconTimingElement(IeBeaconTiming beaconTiming)
{
    m_beaconTiming = beaconTiming;
}

Mac48Address
PeerLink::GetPeerAddress() const
{
    return m_peerAddress;
}

uint16_t
PeerLink::GetLocalAid() const
{
    return m_assocId;
}

uint16_t
PeerLink::GetPeerAid() const
{
    return m_peerAssocId;
}

Time
PeerLink::GetLastBeacon() const
{
    return m_lastBeacon;
}

Time
PeerLink::GetBeaconInterval() const
{
    return m_beaconInterval;
}

IeBeaconTiming
PeerLink::GetBeaconTimingElement() const
{
    return m_beaconTiming;
}

void
PeerLink::MLMECancelPeerLink(PmpReasonCode reason)
{
    StateMachine(CNCL, reason);
}

void
PeerLink::MLMEActivePeerLinkOpen()
{
    StateMachine(ACTOPN);
}

void
PeerLink::MLMEPeeringRequestReject()
{
    StateMachine(REQ_RJCT, REASON11S_PEERING_CANCELLED);
}

void
PeerLink::Close(uint16_t localLinkId, uint16_t peerLinkId, PmpReasonCode reason)
{
    NS_LOG_FUNCTION(this << localLinkId << peerLinkId << reason);
    if (peerLinkId != 0 && m_localLinkId != peerLinkId)
    {
        return;
    }
    if (m_peerLinkId == 0)
    {
        m_peerLinkId = localLinkId;
    }
    else
    {
        if (m_peerLinkId != localLinkId)
        {
            return;
        }
    }
    StateMachine(CLS_ACPT, reason);
}

void
PeerLink::OpenAccept(uint16_t localLinkId, IeConfiguration conf, Mac48Address peerMp)
{
    NS_LOG_FUNCTION(this << localLinkId << peerMp);
    m_peerLinkId = localLinkId;
    m_configuration = conf;
    if (m_peerMeshPointAddress != Mac48Address::GetBroadcast())
    {
        NS_ASSERT(m_peerMeshPointAddress == peerMp);
    }
    else
    {
        m_peerMeshPointAddress = peerMp;
    }
    StateMachine(OPN_ACPT);
}

void
PeerLink::OpenReject(uint16_t localLinkId,
                     IeConfiguration conf,
                     Mac48Address peerMp,
                     PmpReasonCode reason)
{
    NS_LOG_FUNCTION(this << localLinkId << peerMp << reason);
    if (m_peerLinkId == 0)
    {
        m_peerLinkId = localLinkId;
    }
    m_configuration = conf;
    if (m_peerMeshPointAddress != Mac48Address::GetBroadcast())
    {
        NS_ASSERT(m_peerMeshPointAddress == peerMp);
    }
    else
    {
        m_peerMeshPointAddress = peerMp;
    }
    StateMachine(OPN_RJCT, reason);
}

void
PeerLink::ConfirmAccept(uint16_t localLinkId,
                        uint16_t peerLinkId,
                        uint16_t peerAid,
                        IeConfiguration conf,
                        Mac48Address peerMp)
{
    NS_LOG_FUNCTION(this << localLinkId << peerLinkId << peerAid << peerMp);
    if (m_localLinkId != peerLinkId)
    {
        return;
    }
    if (m_peerLinkId == 0)
    {
        m_peerLinkId = localLinkId;
    }
    else
    {
        if (m_peerLinkId != localLinkId)
        {
            return;
        }
    }
    m_configuration = conf;
    m_peerAssocId = peerAid;
    if (m_peerMeshPointAddress != Mac48Address::GetBroadcast())
    {
        NS_ASSERT(m_peerMeshPointAddress == peerMp);
    }
    else
    {
        m_peerMeshPointAddress = peerMp;
    }
    StateMachine(CNF_ACPT);
}

void
PeerLink::ConfirmReject(uint16_t localLinkId,
                        uint16_t peerLinkId,
                        IeConfiguration conf,
                        Mac48Address peerMp,
                        PmpReasonCode reason)
{
    NS_LOG_FUNCTION(this << localLinkId << peerLinkId << peerMp << reason);
    if (m_localLinkId != peerLinkId)
    {
        return;
    }
    if (m_peerLinkId == 0)
    {
        m_peerLinkId = localLinkId;
    }
    else
    {
        if (m_peerLinkId != localLinkId)
        {
            return;
        }
    }
    m_configuration = conf;
    if (m_peerMeshPointAddress != Mac48Address::GetBroadcast())
    {
        NS_ASSERT(m_peerMeshPointAddress == peerMp);
    }
    m_peerMeshPointAddress = peerMp;
    StateMachine(CNF_RJCT, reason);
}

bool
PeerLink::LinkIsEstab() const
{
    return (m_state == ESTAB);
}

bool
PeerLink::LinkIsIdle() const
{
    return (m_state == IDLE);
}

void
PeerLink::SetMacPlugin(Ptr<PeerManagementProtocolMac> plugin)
{
    m_macPlugin = plugin;
}

//-----------------------------------------------------------------------------
// Private
//-----------------------------------------------------------------------------
void
PeerLink::StateMachine(PeerEvent event, PmpReasonCode reasoncode)
{
    switch (m_state)
    {
    case IDLE:
        switch (event)
        {
        case CNCL:
        case CLS_ACPT:
            m_state = IDLE;
            m_linkStatusCallback(m_interface, m_peerAddress, m_peerMeshPointAddress, IDLE, IDLE);
            break;
        case REQ_RJCT:
            SendPeerLinkClose(reasoncode);
            break;
        case ACTOPN:
            m_state = OPN_SNT;
            m_linkStatusCallback(m_interface, m_peerAddress, m_peerMeshPointAddress, IDLE, OPN_SNT);
            SendPeerLinkOpen();
            SetRetryTimer();
            break;
        case OPN_ACPT:
            m_state = OPN_RCVD;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 IDLE,
                                 OPN_RCVD);
            SendPeerLinkConfirm();
            SendPeerLinkOpen();
            SetRetryTimer();
            break;
        default:
            // 11B.5.3.4 of 802.11s Draft D3.0
            // All other events shall be ignored in this state
            break;
        }
        break;
    case OPN_SNT:
        switch (event)
        {
        case TOR1:
            SendPeerLinkOpen();
            m_retryCounter++;
            SetRetryTimer();
            break;
        case CNF_ACPT:
            m_state = CNF_RCVD;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_SNT,
                                 CNF_RCVD);
            ClearRetryTimer();
            SetConfirmTimer();
            break;
        case OPN_ACPT:
            m_state = OPN_RCVD;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_SNT,
                                 OPN_RCVD);
            SendPeerLinkConfirm();
            break;
        case CLS_ACPT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_SNT,
                                 HOLDING);
            ClearRetryTimer();
            SendPeerLinkClose(REASON11S_MESH_CLOSE_RCVD);
            SetHoldingTimer();
            break;
        case OPN_RJCT:
        case CNF_RJCT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_SNT,
                                 HOLDING);
            ClearRetryTimer();
            SendPeerLinkClose(reasoncode);
            SetHoldingTimer();
            break;
        case TOR2:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_SNT,
                                 HOLDING);
            ClearRetryTimer();
            SendPeerLinkClose(REASON11S_MESH_MAX_RETRIES);
            SetHoldingTimer();
            break;
        case CNCL:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_SNT,
                                 HOLDING);
            ClearRetryTimer();
            SendPeerLinkClose(REASON11S_PEERING_CANCELLED);
            SetHoldingTimer();
            break;
        default:
            // 11B.5.3.5 of 802.11s Draft D3.0
            // All other events shall be ignored in this state
            break;
        }
        break;
    case CNF_RCVD:
        switch (event)
        {
        case CNF_ACPT:
            break;
        case OPN_ACPT:
            m_state = ESTAB;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 CNF_RCVD,
                                 ESTAB);
            ClearConfirmTimer();
            SendPeerLinkConfirm();
            NS_ASSERT(m_peerMeshPointAddress != Mac48Address::GetBroadcast());
            break;
        case CLS_ACPT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 CNF_RCVD,
                                 HOLDING);
            ClearConfirmTimer();
            SendPeerLinkClose(REASON11S_MESH_CLOSE_RCVD);
            SetHoldingTimer();
            break;
        case CNF_RJCT:
        case OPN_RJCT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 CNF_RCVD,
                                 HOLDING);
            ClearConfirmTimer();
            SendPeerLinkClose(reasoncode);
            SetHoldingTimer();
            break;
        case CNCL:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 CNF_RCVD,
                                 HOLDING);
            ClearConfirmTimer();
            SendPeerLinkClose(REASON11S_PEERING_CANCELLED);
            SetHoldingTimer();
            break;
        case TOC:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 CNF_RCVD,
                                 HOLDING);
            SendPeerLinkClose(REASON11S_MESH_CONFIRM_TIMEOUT);
            SetHoldingTimer();
            break;
        default:
            // 11B.5.3.6 of 802.11s Draft D3.0
            // All other events shall be ignored in this state
            break;
        }
        break;
    case OPN_RCVD:
        switch (event)
        {
        case TOR1:
            SendPeerLinkOpen();
            m_retryCounter++;
            SetRetryTimer();
            break;
        case CNF_ACPT:
            m_state = ESTAB;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_RCVD,
                                 ESTAB);
            ClearRetryTimer();
            NS_ASSERT(m_peerMeshPointAddress != Mac48Address::GetBroadcast());
            break;
        case CLS_ACPT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_RCVD,
                                 HOLDING);
            ClearRetryTimer();
            SendPeerLinkClose(REASON11S_MESH_CLOSE_RCVD);
            SetHoldingTimer();
            break;
        case OPN_RJCT:
        case CNF_RJCT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_RCVD,
                                 HOLDING);
            ClearRetryTimer();
            SendPeerLinkClose(reasoncode);
            SetHoldingTimer();
            break;
        case TOR2:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_RCVD,
                                 HOLDING);
            ClearRetryTimer();
            SendPeerLinkClose(REASON11S_MESH_MAX_RETRIES);
            SetHoldingTimer();
            break;
        case CNCL:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 OPN_RCVD,
                                 HOLDING);
            ClearRetryTimer();
            SendPeerLinkClose(REASON11S_PEERING_CANCELLED);
            SetHoldingTimer();
            break;
        default:
            // 11B.5.3.7 of 802.11s Draft D3.0
            // All other events shall be ignored in this state
            break;
        }
        break;
    case ESTAB:
        switch (event)
        {
        case OPN_ACPT:
            SendPeerLinkConfirm();
            break;
        case CLS_ACPT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 ESTAB,
                                 HOLDING);
            SendPeerLinkClose(REASON11S_MESH_CLOSE_RCVD);
            SetHoldingTimer();
            break;
        case OPN_RJCT:
        case CNF_RJCT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 ESTAB,
                                 HOLDING);
            ClearRetryTimer();
            SendPeerLinkClose(reasoncode);
            SetHoldingTimer();
            break;
        case CNCL:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 ESTAB,
                                 HOLDING);
            SendPeerLinkClose(REASON11S_PEERING_CANCELLED);
            SetHoldingTimer();
            break;
        default:
            // 11B.5.3.8 of 802.11s Draft D3.0
            // All other events shall be ignored in this state
            break;
        }
        break;
    case HOLDING:
        switch (event)
        {
        case CLS_ACPT:
            ClearHoldingTimer();
            // fall through:
        case TOH:
            m_state = IDLE;
            m_linkStatusCallback(m_interface, m_peerAddress, m_peerMeshPointAddress, HOLDING, IDLE);
            break;
        case OPN_ACPT:
        case CNF_ACPT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 HOLDING,
                                 HOLDING);
            // reason not spec in D2.0
            SendPeerLinkClose(REASON11S_PEERING_CANCELLED);
            break;
        case OPN_RJCT:
        case CNF_RJCT:
            m_state = HOLDING;
            m_linkStatusCallback(m_interface,
                                 m_peerAddress,
                                 m_peerMeshPointAddress,
                                 HOLDING,
                                 HOLDING);
            SendPeerLinkClose(reasoncode);
            break;
        default:
            // 11B.5.3.9 of 802.11s Draft D3.0
            // All other events shall be ignored in this state
            break;
        }
        break;
    }
}

void
PeerLink::ClearRetryTimer()
{
    m_retryTimer.Cancel();
}

void
PeerLink::ClearConfirmTimer()
{
    m_confirmTimer.Cancel();
}

void
PeerLink::ClearHoldingTimer()
{
    m_holdingTimer.Cancel();
}

void
PeerLink::SendPeerLinkClose(PmpReasonCode reasoncode)
{
    IePeerManagement peerElement;
    peerElement.SetPeerClose(m_localLinkId, m_peerLinkId, reasoncode);
    m_macPlugin->SendPeerLinkManagementFrame(m_peerAddress,
                                             m_peerMeshPointAddress,
                                             m_assocId,
                                             peerElement,
                                             m_configuration);
}

void
PeerLink::SendPeerLinkOpen()
{
    IePeerManagement peerElement;
    peerElement.SetPeerOpen(m_localLinkId);
    NS_ASSERT(m_macPlugin);
    m_macPlugin->SendPeerLinkManagementFrame(m_peerAddress,
                                             m_peerMeshPointAddress,
                                             m_assocId,
                                             peerElement,
                                             m_configuration);
}

void
PeerLink::SendPeerLinkConfirm()
{
    IePeerManagement peerElement;
    peerElement.SetPeerConfirm(m_localLinkId, m_peerLinkId);
    m_macPlugin->SendPeerLinkManagementFrame(m_peerAddress,
                                             m_peerMeshPointAddress,
                                             m_assocId,
                                             peerElement,
                                             m_configuration);
}

void
PeerLink::SetHoldingTimer()
{
    NS_ASSERT(m_dot11MeshHoldingTimeout.GetMicroSeconds() != 0);
    m_holdingTimer =
        Simulator::Schedule(m_dot11MeshHoldingTimeout, &PeerLink::HoldingTimeout, this);
}

void
PeerLink::HoldingTimeout()
{
    NS_LOG_FUNCTION(this);
    StateMachine(TOH);
}

void
PeerLink::SetRetryTimer()
{
    NS_ASSERT(m_dot11MeshRetryTimeout.GetMicroSeconds() != 0);
    m_retryTimer = Simulator::Schedule(m_dot11MeshRetryTimeout, &PeerLink::RetryTimeout, this);
}

void
PeerLink::RetryTimeout()
{
    NS_LOG_FUNCTION(this);
    if (m_retryCounter < m_dot11MeshMaxRetries)
    {
        NS_LOG_LOGIC("Retry timeout TOR1");
        StateMachine(TOR1);
    }
    else
    {
        NS_LOG_LOGIC("Retry timeout TOR2");
        StateMachine(TOR2);
    }
}

void
PeerLink::SetConfirmTimer()
{
    NS_ASSERT(m_dot11MeshConfirmTimeout.GetMicroSeconds() != 0);
    m_confirmTimer =
        Simulator::Schedule(m_dot11MeshConfirmTimeout, &PeerLink::ConfirmTimeout, this);
}

void
PeerLink::ConfirmTimeout()
{
    StateMachine(TOC);
}

void
PeerLink::Report(std::ostream& os) const
{
    if (m_state != ESTAB)
    {
        return;
    }
    os << "<PeerLink" << std::endl
       << "localAddress=\"" << m_macPlugin->GetAddress() << "\"" << std::endl
       << "peerInterfaceAddress=\"" << m_peerAddress << "\"" << std::endl
       << "peerMeshPointAddress=\"" << m_peerMeshPointAddress << "\"" << std::endl
       << "metric=\"" << m_macPlugin->GetLinkMetric(m_peerAddress) << "\"" << std::endl
       << "lastBeacon=\"" << m_lastBeacon.GetSeconds() << "\"" << std::endl
       << "localLinkId=\"" << m_localLinkId << "\"" << std::endl
       << "peerLinkId=\"" << m_peerLinkId << "\"" << std::endl
       << "assocId=\"" << m_assocId << "\"" << std::endl
       << "/>" << std::endl;
}
} // namespace dot11s
} // namespace ns3
