public void Constructor_ValuesInitialized()
{
var type = LinkLayerResultType.Success;
var uut = new LinkLayerResult(type);
Assert.AreEqual(type, uut.Result);
}
public void Constructor_Explicit_ValuesInitialized()
{
var nb = "neighbourName";
var msg = new Message(new DataMsg(2), "destination", "source", 1);
var uut = new LinkLayerResult(msg, nb);
Assert.AreEqual(nb, uut.MissingNeighbour);
Assert.AreEqual(msg, uut.DroppedMessage);
Assert.AreEqual(LinkLayerResultType.NextHopNotFound, uut.Result);
}
/// <summary>
/// Sends a new DATA message. Looks up the next-hop in the routing table, and passes message to link-layer.
/// </summary>
/// <param name="msg"></param>
public void SendDataMessage(Message msg)
{
var outgoingMessage = new Message(msg);
if (outgoingMessage.Type != MessageType.Data)
{
throw new ArgumentException("Sorry mate, DATA-messages only.");
}
LinkLayerResult result = null;
//If this is a broadcast-packet, no table-lookup is necessary (and will fail)
if (outgoingMessage.DestinationAddress == SimulationConstants.BroadcastAddress) //RREQs will always fall into this one, even those processed by me, since destination=broadcast
{
result = _linkLayer.SendMessage(outgoingMessage, SimulationConstants.BroadcastAddress); //Broadcasts cannot miss a neighbour
}
//If an active route valid for forwarding exists, find next-hop and send message
if (_aodvHelper.RoutingTable.ActiveRouteExists(outgoingMessage.DestinationAddress))
{
//Find route to destination, to acquire next-hop
var destinationEntry = _aodvHelper.RoutingTable.GetEntry(outgoingMessage.DestinationAddress);
//Update lifetime of active route to destination when it's used per section 6.2 ending.
_aodvHelper.RoutingTable.SetRouteActive(destinationEntry.DestinationAddress);
//Update lifetime of route to next-hop per section 6.2 ending.
var nextHopRoute = _aodvHelper.RoutingTable.GetEntry(destinationEntry.NextHop);
if (nextHopRoute != null)
{
_aodvHelper.RoutingTable.SetRouteActive(nextHopRoute.DestinationAddress);
}
//Update lifetime of route to originator of data (if it was not sent by me) per section 6.2 ending.
if (outgoingMessage.SourceAddress != _localAddress)
{
var sourceRoute = _aodvHelper.RoutingTable.GetEntry(outgoingMessage.SourceAddress);
if (sourceRoute != null)
{
_aodvHelper.RoutingTable.SetRouteActive(sourceRoute.DestinationAddress);
}
}
//Update lifetime of route to previous hop (if it was not sent by me) per section 6.2 ending.
if (outgoingMessage.PreviousHop != _localAddress)
{
var previousHopRoute = _aodvHelper.RoutingTable.GetEntry(outgoingMessage.PreviousHop);
if (previousHopRoute != null)
{
_aodvHelper.RoutingTable.SetRouteActive(previousHopRoute.DestinationAddress);
}
}
result = _linkLayer.SendMessage(outgoingMessage, destinationEntry.NextHop); //Send message along route towards destination. If it fails, routes updated above are invalidated, no worries.
}
//If active route does not exist, but a RREQ has been sent for this destination and are not expired yet
else if (!_aodvHelper.RoutingTable.ActiveRouteExists(outgoingMessage.DestinationAddress) && _aodvHelper.RreqAttemptExist(outgoingMessage.DestinationAddress, _localAddress))
{
ParkMessage(new Message(outgoingMessage)); //Park message and wait for RREP
return;
}
//If any kind of route does NOT exist, OR existing route is invalid/expired, send a new RREQ for the destination
else if (!_aodvHelper.RoutingTable.RouteExists(outgoingMessage.DestinationAddress) || (!_aodvHelper.RoutingTable.GetEntry(outgoingMessage.DestinationAddress)?.Valid ?? true))
{
ParkMessage(new Message(outgoingMessage));
_statistics.RoutingRequestGenerated();
var rreqMsg = _aodvHelper.GenerateInitialRreqMessage(outgoingMessage.DestinationAddress);
_statistics.AddAodvMessageSent(rreqMsg);
result = _linkLayer.SendMessage(rreqMsg, SimulationConstants.BroadcastAddress); //No need to check for missing neighbour in result
}
if (result.Result == LinkLayerResultType.NextHopNotFound)
{
//This is a clear Section 6.11 (i): Link break for next hop of active route while transmiting data (hehe)
//_statistics.AddMessageDropped(e.DroppedMessage);
_statistics.AddDataMessageDroppedNextHopUnavailable(result.DroppedMessage);
//Get a list of all unreachable destinations, because of this link-failure. This also updates and invalidates entries in routing tables.
var unreachableDestinations = _aodvHelper.RoutingTable.HandleAndGetUnreachableDestinations(result.MissingNeighbour);
var rerr = new Rerr(unreachableDestinations);
//If any destinations were affected by this link-failure
if (unreachableDestinations.Count > 0)
{
//Get all nodes that use the now missing link as a part of their route
var precursors = _aodvHelper.RoutingTable.GetEntry(unreachableDestinations[0].UnreachableDestinationAddress).Precursors;
foreach (var precursor in precursors)
{
//Send RERR to precursors if any is available
var rerrMsg = new Message(new Rerr(rerr), precursors[0], _localAddress, _conf.MessageTtlValue);
SendAodvMessage(rerrMsg, precursor);
}
}
}
}
