/// <summary>
/// Place a new message in the incoming-queue of this satellite.
/// </summary>
public void ReceiveMessage(Message.Message incomingMessage)
{
//Receive message with some probability
if (RandomHelper.ReceiveData(_conf.LinkLayerReceptionProbability) && _inputQueue.Count < _conf.LinkBufferSize)
{
_statistics.LinkLayerAddReceivedMessage(incomingMessage);
_inputQueue.Enqueue(new Message.Message(incomingMessage));
}
else
{
_statistics.LinkLayerAddDroppedMessage(incomingMessage);
}
}
/// <summary>
/// Send a message to another satellite.
/// </summary>
public LinkLayerResult SendMessage(Message.Message outgoingMessage, string nextHop)
{
var msg = new Message.Message(outgoingMessage); //Create copy of message
//Dont forward messages with TTL == 0, pr. https://tools.ietf.org/html/rfc1812#section-4.2.2.9 / https://networkengineering.stackexchange.com/questions/10929/when-is-an-ipv4-ttl-decremented-and-what-is-the-drop-condition
if (msg.Ttl <= 0)
{
_statistics.LinkLayerTtlExpired(msg);
_logger.WriteLine("TTL reached 0 for " + msg.Type + " packet to " + msg.DestinationAddress + ", dropping packet.");
return(new LinkLayerResult(LinkLayerResultType.TtlExpired));
}
msg.PreviousHop = _thisSatellite.LocalAddress;
msg.DecrementTtl(); //Decrement TTL on egress part of router
var neighbours = GetAvailableLinks();
var availableLinks = string.Join(", ", from item in neighbours.Values select item.LocalAddress);
//If broadcast to all neighbours
if (msg.DestinationAddress == SimulationConstants.BroadcastAddress || nextHop == SimulationConstants.BroadcastAddress)
{
_logger.WriteLine("Sending " + msg.Type + " broadcast packet. Destination: " + msg.DestinationAddress + ", Source: " + msg.SourceAddress + " Previous-hop: " + msg.PreviousHop + ", Next-hops: " + availableLinks);
foreach (var link in neighbours)
{
msg.AddPropagationDelay(_thisSatellite.Location, link.Value.Location);
link.Value.ReceiveNewMessage(new Message.Message(msg));
}
}
else //Unicast towards specific neighbour (if available)
{
//If neighbour is not found, throw exception
if (!neighbours.ContainsKey(nextHop))
{
_logger.WriteLine("ERROR - LINK NOT FOUND. NextHop: " + nextHop + ", Available links: " + availableLinks);
return(new LinkLayerResult(new Message.Message(msg), nextHop));
}
_logger.WriteLine("Sending packet. Type: " + msg.Type + ", Destination: " + msg.DestinationAddress + ", Source: " + msg.SourceAddress + " Previous-hop: " + msg.PreviousHop + ", Next-hop: " + nextHop + ", Available links: " + availableLinks);
msg.AddPropagationDelay(_thisSatellite.Location, neighbours[nextHop].Location);
neighbours[nextHop].ReceiveNewMessage(new Message.Message(msg));
}
_statistics.LinkLayerAddSentMessage(msg);
return(new LinkLayerResult(LinkLayerResultType.Success));
}
/// <summary>
/// Place a message in this nodes queue (called from another satellite)
/// </summary>
/// <param name="msg">Message that other satellite wants to send to this satellite.</param>
public void ReceiveNewMessage(Message.Message msg)
{
_linkLayer.ReceiveMessage(msg);
}
/// <summary>
/// Send data message to other node
/// </summary>
/// <param name="msg">Message to transmit to other node.</param>
public void SendMessage(Message.Message msg)
{
_networkLayer.SendDataMessage(msg);
}