#include <LinkStateRouting.h>

Inheritance diagram for LinkStateRouting:

Public Member Functions
	LinkStateRouting ()
virtual	~LinkStateRouting ()
Protected Member Functions
virtual void	initialize (int stage)
virtual int	numInitStages () const
virtual void	handleMessage (cMessage *msg)
virtual void	processLINK_STATE_MESSAGE (LinkStateMsg *msg, IPAddress sender)
virtual void	receiveChangeNotification (int category, const cPolymorphic *details)
virtual void	sendToPeers (const std::vector< TELinkStateInfo > &list, bool req, IPAddress exceptPeer)
virtual void	sendToPeer (IPAddress peer, const std::vector< TELinkStateInfo > &list, bool req)
virtual void	sendToIP (LinkStateMsg *msg, IPAddress destAddr)
Protected Attributes
TED *	tedmod
cMessage *	announceMsg
IPAddress	routerId
IPAddressVector	peerIfAddrs

Detailed Description

Implements a minimalistic link state routing protocol that employs flooding. Flooding works like this:

When a router receives a link state packet, it merges the packet contents into its own link state database (ted). If the packet contained new information (ted got updated), the router broadcasts the ted contents to all its other neighbours; otherwise (when the packet didn't contain any new info), nothing happens.

Also: when the announceMsg timer expires, LinkStateRouting sends out an initial link state message. (Currently this happens only once, at the beginning of the simulation). The "request" bit in the message is set then, asking neighbours to send back their link state databases. (FIXME why's this? redundant messaging: same msg is often sent twice: both as reply and as voluntary "announce").

TODO discover peers by "hello". Peers are those from which the router has received a Hello in the last X seconds. Link info to all peers are maintained; links to ex-peers (those haven't heard of for more than X seconds) are assumed to be down.

See NED file for more info.

Definition at line 56 of file LinkStateRouting.h.

Constructor & Destructor Documentation

LinkStateRouting::LinkStateRouting ( )

Definition at line 30 of file LinkStateRouting.cc.

{
    announceMsg = NULL;
}

LinkStateRouting::~LinkStateRouting ( ) [virtual]

Definition at line 35 of file LinkStateRouting.cc.

{
    cancelAndDelete(announceMsg);
}

Member Function Documentation

void LinkStateRouting::handleMessage ( cMessage * msg ) [protected, virtual]

Definition at line 71 of file LinkStateRouting.cc.

{
    if (msg == announceMsg)
    {
        delete announceMsg;
        announceMsg = NULL;
        sendToPeers(tedmod->ted, true, IPAddress());
    }
    else if (!strcmp(msg->getArrivalGate()->getName(), "ipIn"))
    {
        EV << "Processing message from IP: " << msg << endl;
        IPControlInfo *controlInfo = check_and_cast<IPControlInfo *>(msg->getControlInfo());
        IPAddress sender = controlInfo->getSrcAddr();
        processLINK_STATE_MESSAGE(check_and_cast<LinkStateMsg*>(msg), sender);
    }
    else
        ASSERT(false);
}

void LinkStateRouting::initialize ( int stage ) [protected, virtual]

Definition at line 40 of file LinkStateRouting.cc.

{
    // we have to wait until routerId gets assigned in stage 3
    if (stage==4)
    {
        tedmod = TEDAccess().get();

        IRoutingTable *rt = RoutingTableAccess().get();
        routerId = rt->getRouterId();

        // listen for TED modifications
        NotificationBoard *nb = NotificationBoardAccess().get();
        nb->subscribe(this, NF_TED_CHANGED);

        // peers are given as interface names in the "peers" module parameter;
        // store corresponding interface addresses in peerIfAddrs[]
        cStringTokenizer tokenizer(par("peers"));
        IInterfaceTable *ift = InterfaceTableAccess().get();
        const char *token;
        while ((token = tokenizer.nextToken())!=NULL)
        {
            ASSERT(ift->getInterfaceByName(token));
            peerIfAddrs.push_back(ift->getInterfaceByName(token)->ipv4Data()->getIPAddress());
        }

        // schedule start of flooding link state info
        announceMsg = new cMessage("announce");
        scheduleAt(simTime() + exponential(0.01), announceMsg);
    }
}

virtual int LinkStateRouting::numInitStages ( ) const [inline, protected, virtual]

Definition at line 71 of file LinkStateRouting.h.

{return 5;}

void LinkStateRouting::processLINK_STATE_MESSAGE	(	LinkStateMsg *	msg,
		IPAddress	sender
	)			`[protected, virtual]`

Definition at line 118 of file LinkStateRouting.cc.

Referenced by handleMessage().

{
    EV << "received LINK_STATE message from " << sender << endl;

    TELinkStateInfoVector forward;

    unsigned int n = msg->getLinkInfoArraySize();

    bool change = false; // in topology

    // loop through every link in the message
    for (unsigned int i = 0; i < n; i++)
    {
        const TELinkStateInfo& link = msg->getLinkInfo(i);

        TELinkStateInfo *match;

        // process link if we haven't seen this already and timestamp is newer
        if(tedmod->checkLinkValidity(link, match))
        {
            ASSERT(link.sourceId == link.advrouter.getInt());

            EV << "new information found" << endl;

            if(!match)
            {
                // and we have no info on this link so far, store it as it is
                tedmod->ted.push_back(link);
                change = true;
            }
            else
            {
                // copy over the information from it
                if(match->state != link.state)
                {
                    match->state = link.state;
                    change = true;
                }
                match->messageId = link.messageId;
                match->sourceId = link.sourceId;
                match->timestamp = link.timestamp;
                for(int i = 0; i < 8; i++)
                    match->UnResvBandwidth[i] = link.UnResvBandwidth[i];
                match->MaxBandwidth = link.MaxBandwidth;
                match->metric = link.metric;
            }

            forward.push_back(link);
        }
    }

    if(change)
        tedmod->rebuildRoutingTable();

    if(msg->getRequest())
    {
        sendToPeer(sender, tedmod->ted, false);
    }

    if(forward.size() > 0)
    {
        sendToPeers(forward, false, sender);
    }

    delete msg;
}

void LinkStateRouting::receiveChangeNotification	(	int	category,
		const cPolymorphic *	details
	)			`[protected, virtual]`

Called by the NotificationBoard whenever a change of a category occurs to which this client has subscribed.

Implements INotifiable.

Definition at line 90 of file LinkStateRouting.cc.

{
    Enter_Method_Silent();
    printNotificationBanner(category, details);

    ASSERT(category == NF_TED_CHANGED);

    EV << "TED changed\n";

    TEDChangeInfo *d = check_and_cast<TEDChangeInfo *>(details);

    unsigned int k = d->getTedLinkIndicesArraySize();

    ASSERT(k > 0);

    // build linkinfo list
    std::vector<TELinkStateInfo> links;
    for (unsigned int i = 0; i < k; i++)
    {
        unsigned int index = d->getTedLinkIndices(i);

        tedmod->updateTimestamp(&tedmod->ted[index]);
        links.push_back(tedmod->ted[index]);
    }

    sendToPeers(links, false, IPAddress());
}

void LinkStateRouting::sendToIP	(	LinkStateMsg *	msg,
		IPAddress	destAddr
	)			`[protected, virtual]`

Definition at line 224 of file LinkStateRouting.cc.

Referenced by sendToPeer().

{
    // attach control info to packet
    IPControlInfo *controlInfo = new IPControlInfo();
    controlInfo->setDestAddr(destAddr);
    controlInfo->setSrcAddr(routerId);
    controlInfo->setProtocol(IP_PROT_OSPF);
    msg->setControlInfo(controlInfo);

    int length = msg->getLinkInfoArraySize() * 72;
    msg->setByteLength(length);

    msg->addPar("color") = TED_TRAFFIC;

    send(msg, "ipOut");
}

void LinkStateRouting::sendToPeer	(	IPAddress	peer,
		const std::vector< TELinkStateInfo > &	list,
		bool	req
	)			`[protected, virtual]`

Definition at line 209 of file LinkStateRouting.cc.

Referenced by processLINK_STATE_MESSAGE(), and sendToPeers().

{
    EV << "sending LINK_STATE message to " << peer << endl;

    LinkStateMsg *out = new LinkStateMsg("link state");

    out->setLinkInfoArraySize(list.size());
    for (unsigned int j = 0; j < list.size(); j++)
        out->setLinkInfo(j, list[j]);

    out->setRequest(req);

    sendToIP(out, peer);
}

void LinkStateRouting::sendToPeers	(	const std::vector< TELinkStateInfo > &	list,
		bool	req,
		IPAddress	exceptPeer
	)			`[protected, virtual]`

Definition at line 185 of file LinkStateRouting.cc.

Referenced by handleMessage(), processLINK_STATE_MESSAGE(), and receiveChangeNotification().

{
    EV << "sending LINK_STATE message to peers" << endl;

    // send "list" to every peer (linkid in our ted[] entries???) in a LinkStateMsg
    for (unsigned int i = 0; i < tedmod->ted.size(); i++)
    {
        if(tedmod->ted[i].advrouter != routerId)
            continue;

        if(tedmod->ted[i].linkid == exceptPeer)
            continue;

        if(!tedmod->ted[i].state)
            continue;

        if(find(peerIfAddrs.begin(), peerIfAddrs.end(), tedmod->ted[i].local) == peerIfAddrs.end())
            continue;

        // send a copy
        sendToPeer(tedmod->ted[i].linkid, list, req);
    }
}