inet::EtherLLC Class Reference

Implements the LLC sub-layer of the Datalink Layer in Ethernet networks. More...

#include <EtherLLC.h>

Inheritance diagram for inet::EtherLLC:

Public Member Functions
virtual bool	handleOperationStage (LifecycleOperation *operation, int stage, IDoneCallback *doneCallback) override
	Perform one stage of a lifecycle operation. More...
Public Member Functions inherited from inet::ILifecycle
virtual	~ILifecycle ()

Protected Types
typedef std::map< int, int >	DsapToPortMap

Protected Member Functions
virtual void	initialize (int stage) override
virtual int	numInitStages () const override
virtual void	handleMessage (cMessage *msg) override
virtual void	processPacketFromHigherLayer (cPacket *msg)
virtual void	processFrameFromMAC (EtherFrameWithLLC *msg)
virtual void	handleRegisterSAP (cMessage *msg)
virtual void	handleDeregisterSAP (cMessage *msg)
virtual void	handleSendPause (cMessage *msg)
virtual int	findPortForSAP (int sap)
virtual void	start ()
virtual void	stop ()
virtual void	refreshDisplay () const override

Protected Attributes
int	seqNum
DsapToPortMap	dsapToPort
bool	isUp
long	dsapsRegistered
long	totalFromHigherLayer
long	totalFromMAC
long	totalPassedUp
long	droppedUnknownDSAP

Static Protected Attributes
static simsignal_t	dsapSignal = registerSignal("dsap")
static simsignal_t	encapPkSignal = registerSignal("encapPk")
static simsignal_t	decapPkSignal = registerSignal("decapPk")
static simsignal_t	passedUpPkSignal = registerSignal("passedUpPk")
static simsignal_t	droppedPkUnknownDSAPSignal = registerSignal("droppedPkUnknownDSAP")
static simsignal_t	pauseSentSignal = registerSignal("pauseSent")

Detailed Description

Implements the LLC sub-layer of the Datalink Layer in Ethernet networks.

Member Typedef Documentation

typedef std::map<int, int> inet::EtherLLC::DsapToPortMap

protected

Member Function Documentation

int inet::EtherLLC::findPortForSAP ( int  sap )

protectedvirtual

Referenced by processFrameFromMAC().

{
    auto it = dsapToPort.find(dsap);
    return (it == dsapToPort.end()) ? -1 : it->second;
}

void inet::EtherLLC::handleDeregisterSAP ( cMessage *  msg )

protectedvirtual

Referenced by handleMessage().

{
    Ieee802Ctrl *etherctrl = dynamic_cast<Ieee802Ctrl *>(msg->getControlInfo());
    if (!etherctrl)
        throw cRuntimeError("packet `%s' from higher layer received without Ieee802Ctrl", msg->getName());
    int dsap = etherctrl->getDsap();

    EV << "Deregistering higher layer with DSAP=" << dsap << "\n";

    if (dsapToPort.find(dsap) == dsapToPort.end())
        throw cRuntimeError("DSAP=%d not registered with port=%d", dsap, dsapToPort[dsap]);

    // delete from table (don't care if it's not in there)
    dsapToPort.erase(dsapToPort.find(dsap));
    dsapsRegistered = dsapToPort.size();
    emit(dsapSignal, -1L);
    delete msg;
}

void inet::EtherLLC::handleMessage ( cMessage *  msg )

overrideprotectedvirtual

{
    if (!isUp) {
        EV << "EtherLLC is down -- discarding message\n";
        delete msg;
        return;
    }

    if (msg->arrivedOn("lowerLayerIn")) {
        // frame received from lower layer
        EtherFrameWithLLC *etherFrameWithLLC = dynamic_cast<EtherFrameWithLLC *>(msg);
        if (etherFrameWithLLC) {
            processFrameFromMAC(etherFrameWithLLC);
        }
        else {
            EV << "Drop received " << msg->getClassName() << " msg.\n";
            delete msg;
        }
    }
    else {
        switch (msg->getKind()) {
            case IEEE802CTRL_DATA:
                // data received from higher layer
                processPacketFromHigherLayer(PK(msg));
                break;

            case IEEE802CTRL_REGISTER_DSAP:
                // higher layer registers itself
                handleRegisterSAP(msg);
                break;

            case IEEE802CTRL_DEREGISTER_DSAP:
                // higher layer deregisters itself
                handleDeregisterSAP(msg);
                break;

            case IEEE802CTRL_SENDPAUSE:
                // higher layer want MAC to send PAUSE frame
                handleSendPause(msg);
                break;

            default:
                throw cRuntimeError("Received message `%s' with unknown message kind %d",
                    msg->getName(), msg->getKind());
        }
    }
}

bool inet::EtherLLC::handleOperationStage ( LifecycleOperation *  operation, int  stage, IDoneCallback *  doneCallback  )

overridevirtual

Perform one stage of a lifecycle operation.

Processing may be done entirely within this method, or may be a longer process that involves nonzero simulation time or several events, and is triggered by this method call.

Return value: true = "done"; false = "not yet done, will invoke doneCallback when done"

Implements inet::ILifecycle.

{
    Enter_Method_Silent();
    if (dynamic_cast<NodeStartOperation *>(operation)) {
        if ((NodeStartOperation::Stage)stage == NodeStartOperation::STAGE_NETWORK_LAYER)
            start();
    }
    else if (dynamic_cast<NodeShutdownOperation *>(operation)) {
        if ((NodeShutdownOperation::Stage)stage == NodeShutdownOperation::STAGE_NETWORK_LAYER)
            stop();
    }
    else if (dynamic_cast<NodeCrashOperation *>(operation)) {
        if ((NodeCrashOperation::Stage)stage == NodeCrashOperation::STAGE_CRASH)
            stop();
    }
    return true;
}

void inet::EtherLLC::handleRegisterSAP ( cMessage *  msg )

protectedvirtual

Referenced by handleMessage().

{
    int port = msg->getArrivalGate()->getIndex();
    Ieee802Ctrl *etherctrl = dynamic_cast<Ieee802Ctrl *>(msg->getControlInfo());
    if (!etherctrl)
        throw cRuntimeError("packet `%s' from higher layer received without Ieee802Ctrl", msg->getName());
    int dsap = etherctrl->getDsap();

    EV << "Registering higher layer with DSAP=" << dsap << " on port=" << port << "\n";

    if (dsapToPort.find(dsap) != dsapToPort.end())
        throw cRuntimeError("DSAP=%d already registered with port=%d", dsap, dsapToPort[dsap]);

    dsapToPort[dsap] = port;
    dsapsRegistered = dsapToPort.size();
    emit(dsapSignal, 1L);
    delete msg;
}

void inet::EtherLLC::handleSendPause ( cMessage *  msg )

protectedvirtual

Referenced by handleMessage().

{
    Ieee802Ctrl *etherctrl = dynamic_cast<Ieee802Ctrl *>(msg->getControlInfo());
    if (!etherctrl)
        throw cRuntimeError("PAUSE command `%s' from higher layer received without Ieee802Ctrl", msg->getName());

    int pauseUnits = etherctrl->getPauseUnits();
    EV << "Creating and sending PAUSE frame, with duration=" << pauseUnits << " units\n";

    // create Ethernet frame
    char framename[40];
    sprintf(framename, "pause-%d-%d", getId(), seqNum++);
    EtherPauseFrame *frame = new EtherPauseFrame(framename);
    frame->setPauseTime(pauseUnits);
    MACAddress dest = etherctrl->getDest();
    if (dest.isUnspecified())
        dest = MACAddress::MULTICAST_PAUSE_ADDRESS;
    frame->setDest(dest);
    frame->setByteLength(ETHER_PAUSE_COMMAND_PADDED_BYTES);

    send(frame, "lowerLayerOut");
    emit(pauseSentSignal, pauseUnits);

    delete msg;
}

void inet::EtherLLC::initialize ( int  stage )

overrideprotectedvirtual

{
    cSimpleModule::initialize(stage);

    if (stage == INITSTAGE_LOCAL) {
        seqNum = 0;
        WATCH(seqNum);

        dsapsRegistered = totalFromHigherLayer = totalFromMAC = totalPassedUp = droppedUnknownDSAP = 0;

        WATCH(dsapsRegistered);
        WATCH(totalFromHigherLayer);
        WATCH(totalFromMAC);
        WATCH(totalPassedUp);
        WATCH(droppedUnknownDSAP);
    }
    else if (stage == INITSTAGE_LINK_LAYER) {
        // lifecycle
        NodeStatus *nodeStatus = dynamic_cast<NodeStatus *>(findContainingNode(this)->getSubmodule("status"));
        isUp = !nodeStatus || nodeStatus->getState() == NodeStatus::UP;
        if (isUp)
            start();
    }
}

virtual int inet::EtherLLC::numInitStages ( ) const

inlineoverrideprotectedvirtual

{ return NUM_INIT_STAGES; }

void inet::EtherLLC::processFrameFromMAC ( EtherFrameWithLLC *  msg )

protectedvirtual

Referenced by handleMessage().

{
    // check SAP
    int sap = frame->getDsap();
    int port = findPortForSAP(sap);
    if (port < 0) {
        EV << "No higher layer registered for DSAP=" << sap << ", discarding frame `" << frame->getName() << "'\n";
        droppedUnknownDSAP++;
        emit(droppedPkUnknownDSAPSignal, frame);
        delete frame;
        return;
    }

    // decapsulate it and pass up to higher layer
    cPacket *higherlayermsg = frame->decapsulate();

    Ieee802Ctrl *etherctrl = new Ieee802Ctrl();
    etherctrl->setSsap(frame->getSsap());
    etherctrl->setDsap(frame->getDsap());
    etherctrl->setSrc(frame->getSrc());
    etherctrl->setDest(frame->getDest());
    higherlayermsg->setControlInfo(etherctrl);

    EV << "Decapsulating frame `" << frame->getName() << "', "
                                                         "passing up contained packet `" << higherlayermsg->getName() << "' "
                                                                                                                         "to higher layer " << port << "\n";

    totalFromMAC++;
    emit(decapPkSignal, higherlayermsg);

    // pass up to higher layer
    totalPassedUp++;
    emit(passedUpPkSignal, higherlayermsg);
    send(higherlayermsg, "upperLayerOut", port);
    delete frame;
}

void inet::EtherLLC::processPacketFromHigherLayer ( cPacket *  msg )

protectedvirtual

Referenced by handleMessage().

{
    if (msg->getByteLength() > (MAX_ETHERNET_DATA_BYTES - ETHER_LLC_HEADER_LENGTH))
        throw cRuntimeError("packet from higher layer (%d bytes) plus LLC header exceeds maximum Ethernet payload length (%d)", (int)(msg->getByteLength()), MAX_ETHERNET_DATA_BYTES);

    totalFromHigherLayer++;
    emit(encapPkSignal, msg);

    // Creates MAC header information and encapsulates received higher layer data
    // with this information and transmits resultant frame to lower layer

    // create Ethernet frame, fill it in from Ieee802Ctrl and encapsulate msg in it
    EV << "Encapsulating higher layer packet `" << msg->getName() << "' for MAC\n";
    EV << "Sent from " << getSimulation()->getModule(msg->getSenderModuleId())->getFullPath() << " at " << msg->getSendingTime() << " and was created " << msg->getCreationTime() << "\n";

    Ieee802Ctrl *etherctrl = dynamic_cast<Ieee802Ctrl *>(msg->removeControlInfo());
    if (!etherctrl)
        throw cRuntimeError("packet `%s' from higher layer received without Ieee802Ctrl", msg->getName());

    EtherFrameWithLLC *frame = new EtherFrameWithLLC(msg->getName());

    frame->setControl(0);
    frame->setSsap(etherctrl->getSsap());
    frame->setDsap(etherctrl->getDsap());
    frame->setDest(etherctrl->getDest());    // src address is filled in by MAC
    frame->setByteLength(ETHER_MAC_FRAME_BYTES + ETHER_LLC_HEADER_LENGTH);
    delete etherctrl;

    frame->encapsulate(msg);
    if (frame->getByteLength() < MIN_ETHERNET_FRAME_BYTES)
        frame->setByteLength(MIN_ETHERNET_FRAME_BYTES);

    send(frame, "lowerLayerOut");
}

void inet::EtherLLC::refreshDisplay ( ) const

overrideprotectedvirtual

{
    char buf[80];
    sprintf(buf, "passed up: %ld\nsent: %ld", totalPassedUp, totalFromHigherLayer);

    if (droppedUnknownDSAP > 0) {
        sprintf(buf + strlen(buf), "\ndropped (wrong DSAP): %ld", droppedUnknownDSAP);
    }

    getDisplayString().setTagArg("t", 0, buf);
}

void inet::EtherLLC::start ( )

protectedvirtual

Referenced by handleOperationStage(), and initialize().

{
    dsapToPort.clear();
    dsapsRegistered = dsapToPort.size();
    isUp = true;
}

void inet::EtherLLC::stop ( )

protectedvirtual

Referenced by handleOperationStage().

{
    dsapToPort.clear();
    dsapsRegistered = dsapToPort.size();
    isUp = false;
}

Member Data Documentation

simsignal_t inet::EtherLLC::decapPkSignal = registerSignal("decapPk")

staticprotected

Referenced by processFrameFromMAC().

simsignal_t inet::EtherLLC::droppedPkUnknownDSAPSignal = registerSignal("droppedPkUnknownDSAP")

staticprotected

Referenced by processFrameFromMAC().

long inet::EtherLLC::droppedUnknownDSAP

protected

Referenced by initialize(), processFrameFromMAC(), and refreshDisplay().

simsignal_t inet::EtherLLC::dsapSignal = registerSignal("dsap")

staticprotected

Referenced by handleDeregisterSAP(), and handleRegisterSAP().

long inet::EtherLLC::dsapsRegistered

protected

Referenced by handleDeregisterSAP(), handleRegisterSAP(), initialize(), start(), and stop().

DsapToPortMap inet::EtherLLC::dsapToPort

protected

Referenced by findPortForSAP(), handleDeregisterSAP(), handleRegisterSAP(), start(), and stop().

simsignal_t inet::EtherLLC::encapPkSignal = registerSignal("encapPk")

staticprotected

Referenced by processPacketFromHigherLayer().

bool inet::EtherLLC::isUp

protected

Referenced by handleMessage(), initialize(), start(), and stop().

simsignal_t inet::EtherLLC::passedUpPkSignal = registerSignal("passedUpPk")

staticprotected

Referenced by processFrameFromMAC().

simsignal_t inet::EtherLLC::pauseSentSignal = registerSignal("pauseSent")

staticprotected

Referenced by handleSendPause().

int inet::EtherLLC::seqNum

protected

Referenced by handleSendPause(), and initialize().

long inet::EtherLLC::totalFromHigherLayer

protected

Referenced by initialize(), processPacketFromHigherLayer(), and refreshDisplay().

long inet::EtherLLC::totalFromMAC

protected

Referenced by initialize(), and processFrameFromMAC().

long inet::EtherLLC::totalPassedUp

protected

Referenced by initialize(), processFrameFromMAC(), and refreshDisplay().

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The documentation for this class was generated from the following files:

• EtherLLC.h
• EtherLLC.cc