public Rrep(Rrep rrep)
{
R = rrep.R;
A = rrep.A;
PrefixSize = rrep.PrefixSize;
HopCount = rrep.HopCount;
DestinationAddress = rrep.DestinationAddress;
DestinationSequenceNumber = rrep.DestinationSequenceNumber;
OriginatorAddress = rrep.OriginatorAddress;
Lifetime = rrep.Lifetime;
}
/// <summary>
/// Handles an incoming RREQ packet.
/// </summary>
/// <param name="incomingPacket"></param>
private void HandleRreq(Message incomingPacket)
{
//Processing RREQ according to section 6.5
var rreq = (Rreq)incomingPacket.Payload; //Cast message to right type
//Check that received RREQ has not been received and processed before
if (_aodvHelper.RreqAttemptExist(rreq.DestinationAddress, rreq.OriginatorAddress))
{
_logger.WriteLine("Incoming RREQ from " + rreq.OriginatorAddress + " discarded, since it has been processed before.");
return; //Discard RREQ
}
//RREQ not received before, place in buffer with 0 as attempt number
_aodvHelper.AddBufferedRreqAttempt(new BufferedRreqAttempt(0, rreq, _conf.AodvConfiguration.PathDiscoveryTime));
//First, create/update route to previous hop. If route to previous hop exists, update lifetime
if (_aodvHelper.RoutingTable.ActiveRouteExists(incomingPacket.PreviousHop))
{
var prevRoute = _aodvHelper.RoutingTable.GetEntry(incomingPacket.PreviousHop);
prevRoute.Valid = true;
prevRoute.HopCount = 1;
prevRoute.NextHop = incomingPacket.PreviousHop;
prevRoute.ExpirationTime = _time.GetFutureTime(_aodvParameters.ActiveRouteTimeout);
_logger.WriteLine("RREQ handler: Updating route to previous hop: " + incomingPacket.PreviousHop + " for RREQ #" + rreq.RouteRequestId);
_aodvHelper.RoutingTable.UpdateEntry(prevRoute);
}
else //Route did not exist, so create it
{
var prevHopEntry = new AodvTableEntry
{
Valid = true,
DestinationAddress = incomingPacket.PreviousHop,
DestinationSequenceNumber = 0,
ValidDestinationSequenceNumberFlag = false, //(He's my neighbour, so even though I dont know his sequence number, I know that he's there)
HopCount = 1, //Only 1 hop to previous neighbour (duh)
NextHop = incomingPacket.PreviousHop,
ExpirationTime = _time.GetFutureTime(_aodvParameters.ActiveRouteTimeout)
};
_logger.WriteLine("RREQ handler: Adding route to previous hop: " + incomingPacket.PreviousHop + " for RREQ #" + rreq.RouteRequestId);
_aodvHelper.RoutingTable.AddEntry(prevHopEntry);
}
//RREQ has not been seen before or was not sent by me, continue to process it.
rreq.HopCount = rreq.HopCount + 1; //Increment HopCount in RREQ, since me receiving it, was one hop more
//Create or update reverse route to RREQ Originator
var oldEntry = _aodvHelper.RoutingTable.GetEntry(rreq.OriginatorAddress);
var minimalLifetime = _aodvParameters.MinimalLifetime(rreq.HopCount);
//No route to originator exists, create it
if (oldEntry == null)
{
var originatorRoute = new AodvTableEntry
{
DestinationAddress = rreq.OriginatorAddress,
DestinationSequenceNumber = rreq.OriginatorSequenceNumber,
ValidDestinationSequenceNumberFlag = true,
HopCount = rreq.HopCount,
Valid = true,
NextHop = incomingPacket.PreviousHop,
ExpirationTime = minimalLifetime
};
_logger.WriteLine("RREQ handler: Adding route to originator: " + rreq.OriginatorAddress + " for RREQ #" + rreq.RouteRequestId);
_aodvHelper.RoutingTable.AddEntry(originatorRoute);
}
else //Route exists, update existing entry
{
var originatorRoute = new AodvTableEntry
{
DestinationAddress = rreq.OriginatorAddress,
DestinationSequenceNumber = rreq.OriginatorSequenceNumber > oldEntry.DestinationSequenceNumber ? rreq.OriginatorSequenceNumber : oldEntry.DestinationSequenceNumber, //See section 6.5, action 1.
ValidDestinationSequenceNumberFlag = true,
HopCount = rreq.HopCount,
Valid = true,
NextHop = incomingPacket.PreviousHop,
ExpirationTime = oldEntry.ExpirationTime > minimalLifetime ? oldEntry.ExpirationTime : minimalLifetime
};
_logger.WriteLine("RREQ handler: Updating route to originator: " + rreq.OriginatorAddress + " for RREQ #" + rreq.RouteRequestId);
_aodvHelper.RoutingTable.UpdateEntry(originatorRoute); //And now we have a route towards the originator that can be used. neat-o.
}
//If I am the destination specified in RREQ
if (rreq.DestinationAddress == _localAddress) //Section 6.6 (i) and section 6.6.1
{
//Increment my sequence number, if DSN in RREQ is 1 larger per secton 6.6.1
if (rreq.DestinationSequenceNumber == _aodvHelper.RoutingTable.SequenceNumber + 1)
{
_aodvHelper.RoutingTable.IncrementSequenceNumber();
}
var rrep = new Rrep
{
OriginatorAddress = rreq.OriginatorAddress,
DestinationAddress = rreq.DestinationAddress,
DestinationSequenceNumber = _aodvHelper.RoutingTable.SequenceNumber,
HopCount = 0,
Lifetime = _time.GetFutureTime(_aodvParameters.MyRouteTimeout) //Section 6.6.1, see also section 10.
};
var responseMsg = new Message(rrep, rreq.OriginatorAddress, _localAddress, _conf.MessageTtlValue);
SendAodvMessage(responseMsg, incomingPacket.PreviousHop); //Send RREP to previous hop, which is where I received the RREQ from
}
//If I have an active route to destination, which upholds requirements in section 6.6 (ii), see section 6.6.2
else if (_aodvHelper.RoutingTable.ActiveRouteExists(rreq.DestinationAddress) && //If I have an active route
_aodvHelper.RoutingTable.GetEntry(rreq.DestinationAddress).ValidDestinationSequenceNumberFlag && //and the route has a valid dsn
_aodvHelper.RoutingTable.GetEntry(rreq.DestinationAddress).DestinationSequenceNumber >= rreq.DestinationSequenceNumber && //and route dsn is >= rreq.dsn
!rreq.D) //and rreq must NOT only be answered by destination
{
var forwardRoute = _aodvHelper.RoutingTable.GetEntry(rreq.DestinationAddress);
var rrep = new Rrep
{
OriginatorAddress = rreq.OriginatorAddress,
DestinationAddress = rreq.DestinationAddress,
DestinationSequenceNumber = forwardRoute.DestinationSequenceNumber,
HopCount = forwardRoute.HopCount,
Lifetime = _time.GetFutureTime((forwardRoute.ExpirationTime - _time.CurrentTime).TotalSeconds) //6.6.2, "subtract current time from expiration time in route table entry"
};
//Add previous hop of incoming message to precursor list of destination
_aodvHelper.RoutingTable.AddPrecursorToEntry(rreq.DestinationAddress, incomingPacket.PreviousHop);
//Add next-hop of forward route to precursor list of originator
_aodvHelper.RoutingTable.AddPrecursorToEntry(rreq.OriginatorAddress, forwardRoute.NextHop);
//Place RREP in outbox
var responseMsg = new Message(rrep, rreq.OriginatorAddress, _localAddress, _conf.MessageTtlValue);
SendAodvMessage(responseMsg, incomingPacket.PreviousHop); //Send RREP to previous hop, which is where I received the RREQ from
//Send gratuitous RREP if required in RREQ, specified in section 6.6.3. Dont send it, if path to destination goes through previousHop
if (rreq.G)
{
var gratuitousRrep = new Rrep
{
HopCount = _aodvHelper.RoutingTable.GetEntry(rreq.OriginatorAddress).HopCount,
DestinationAddress = rreq.OriginatorAddress,
DestinationSequenceNumber = rreq.OriginatorSequenceNumber,
OriginatorAddress = rreq.DestinationAddress,
Lifetime = _time.GetFutureTime((_aodvHelper.RoutingTable.GetEntry(rreq.OriginatorAddress).ExpirationTime - _time.CurrentTime).TotalSeconds) //"Remaining lifetime of route towards RREQ originator, as known by intermediate node" (expiration time - current time = remaining time)
};
var gratuitousMsg = new Message(gratuitousRrep, rreq.DestinationAddress, _localAddress, _conf.MessageTtlValue);
SendAodvMessage(gratuitousMsg, forwardRoute.NextHop); //Gratuitous RREP sent forward
}
}
//Else, I have no active route and am not the destination
else
{
var outMsg = new Message(incomingPacket);
rreq.DestinationSequenceNumber = Math.Max(rreq.DestinationSequenceNumber, _aodvHelper.RoutingTable.GetEntry(rreq.DestinationAddress)?.DestinationSequenceNumber ?? -1); //Set DSN to max of rreq.dsn or table[destination].dsn
outMsg.Payload = new Rreq(rreq);
outMsg.DestinationAddress = SimulationConstants.BroadcastAddress;
SendAodvMessage(outMsg, SimulationConstants.BroadcastAddress);
}
}
