private void IncomingAodvRouteRequestMessageHandler(NetSimMessage message)
{
AodvTable aodvTable = (AodvTable)this.Table;
AodvRouteRequestMessage reqMessage = (AodvRouteRequestMessage)message;
// if this node was sender of request - or has already a cached version of request
if (this.IsOwnRequest(reqMessage) || this.HasCachedRequest(reqMessage))
{
// ignore message and proceed
return;
}
// add request to cache
this.AddCachedRequest(reqMessage);
// add reverse routing entry - if route doesn't exist or sequencenr is newer
aodvTable.HandleRequestReverseRouteCaching(reqMessage);
// update request message - increase hopcount and update last hop
reqMessage.LastHop = this.Client.Id;
reqMessage.HopCount += 1;
// check if message destination is current node
if (reqMessage.Receiver.Equals(this.Client.Id))
{
// send back rrep mesage the reverse way
var response = new AodvRouteReplyMessage()
{
Receiver = reqMessage.Sender,
Sender = this.Client.Id,
ReceiverSequenceNr = (AodvSequence)this.CurrentSequence.Clone(),
LastHop = this.Client.Id
};
// enqueue message for sending
this.SendMessage(response);
}
else
{
// Check if route was cached
var searchRoute = aodvTable.SearchCachedRoute(reqMessage);
if (searchRoute != null)
{
// send reply back to requester - send back rrep mesage the reverse way
var response = new AodvRouteReplyMessage()
{
Receiver = reqMessage.Sender,
Sender = searchRoute.Destination,
ReceiverSequenceNr = (AodvSequence)searchRoute.SequenceNr.Clone(),
HopCount = searchRoute.Metric,
LastHop = this.Client.Id
};
// enqueue message for sending
this.SendMessage(response);
}
else
{
// forward message to outgoing messages
this.SendMessage(reqMessage);
}
}
}
/// <summary>
/// Determines whether the given dsr route request message is a own request.
/// </summary>
/// <param name="reqMessage">The request message.</param>
/// <returns>
/// <c>true</c> if is own request; otherwise, <c>false</c>.
/// </returns>
private bool IsOwnRequest(AodvRouteRequestMessage reqMessage)
{
return(reqMessage.Sender.Equals(this.Client.Id));
}
/// <summary>
/// Determines whether this protocol instance has a cached request the specified request id.
/// </summary>
/// <param name="reqMessaged">The request messaged.</param>
/// <returns>
/// <c>true</c> if is cached request; otherwise, <c>false</c>.
/// </returns>
private bool HasCachedRequest(AodvRouteRequestMessage reqMessaged)
{
return(this.RequestCache
.FirstOrDefault(r => r.Id.Equals(reqMessaged.Sender))?.HasCachedRequest(reqMessaged.RequestId) ?? false);
}