private void PerformLabelAction(MPLSPackage package, NHLFETableRow NHLFE, byte TTL, ref string poppedLabelStack)
{
if (NHLFE.OutPort != null)
{
package.Port = (ushort)NHLFE.OutPort;
}
switch (NHLFE.Action)
{
case LabelActions.POP:
if (poppedLabelStack.Equals("-"))
{
poppedLabelStack = package.PeekTopLabel().Number.ToString();
}
else
{
poppedLabelStack += "," + package.PeekTopLabel().Number.ToString();
}
AddLog($"Popped top label: {package.PeekTopLabel().Number}", LogType.Information, Window.ShowDetailedRoutingLogs);
package.PopTopLabel();
if (package.LabelStack.IsEmpty())
{
AddLog("[MPLS->IP] Copying TTL from MPLS level 1 label to IP header", LogType.Information, Window.ShowDetailedTTLLogs);
package.TTL = TTL;
}
else
{
AddLog("[MPLS] Copying TTL from the previous outermost label to the new [lower level] outermost one", LogType.Information, Window.ShowDetailedTTLLogs);
package.PeekTopLabel().TTL = TTL;
}
break;
case LabelActions.SWAP:
AddLog($"Swapped top label: {package.PeekTopLabel().Number} to {(short)NHLFE.OutLabel}", LogType.Information, Window.ShowDetailedRoutingLogs);
package.PopTopLabel();
package.PushLabel(new Label((short)NHLFE.OutLabel));
package.PeekTopLabel().TTL = TTL;
break;
case LabelActions.PUSH:
AddLog($"Pushed new label: {(short)NHLFE.OutLabel}", LogType.Information, Window.ShowDetailedRoutingLogs);
package.PushLabel(new Label((short)NHLFE.OutLabel));
if (poppedLabelStack.Equals("Push first label on IP package"))
{
AddLog("[MPLS] Copying TTL from IP header", LogType.Information, Window.ShowDetailedTTLLogs);
poppedLabelStack = "-";
}
else
{
AddLog("[MPLS] Copying TTL from the previous outermost label to the new [higher level] outermost one", LogType.Information, Window.ShowDetailedTTLLogs);
}
package.PeekTopLabel().TTL = TTL;
break;
default:
break;
}
}
private MPLSPackage PerformMplsNotEmptyPacketRouting(MPLSPackage package)
{
var labelTTL = package.PeekTopLabel().TTL;
string poppedLabelStack = "-";
while (true)
{
if (package.LabelStack.IsEmpty()) // in case if we are egress LER
{
return(package);
}
AddLog($"Looking for NHLFE_ID in ILM table...", LogType.Information, Window.ShowDetailedRoutingLogs);
var ilmRow = RoutingTables.ilmTable.Rows.FirstOrDefault(row => row.IncPort == package.Port && package.PeekTopLabel().Number == (short)row.IncLabel && poppedLabelStack.Equals(row.PoppedLabelStack));
// After completing previous NHFLE action (with nextID==null), check, if there is any rule for such (incPort, incLabel, poppedLabelStack) entry
// i.e. let's say that we popped one label in the previous action. We couldn't have NEXT_ID filled, because router can only see what is in the outermost label.
// But in order to disgunish, for example, label 17 that was nested from label 17 that was not, we must remember a stack of labels that have been popped.
// See Tools/Table Rows/IlmTableRow.cs/incLabel description for more detailed explanation.
if (ilmRow == null)
{
AddLog($"Couldn't find matching entry!", LogType.CantFindMatchingEntry, Window.ShowDetailedRoutingLogs);
return(null);
}
AddLog($"NHLFE_ID for incoming port={package.Port}, incoming label={package.PeekTopLabel().Number}, popped labels={(poppedLabelStack == "-" ? "NULL" : poppedLabelStack)}, is: {ilmRow.NHLFE_ID}", LogType.Information, Window.ShowDetailedRoutingLogs);
var currentNHLFE = RoutingTables.nhlfeTable.Rows.FirstOrDefault(row => row.ID == ilmRow.NHLFE_ID);
if (currentNHLFE == null)
{
// routing information is missing
AddLog($"Couldn't find NHLFE entry!", LogType.Error, Window.ShowDetailedRoutingLogs);
return(null);
}
while (true)
{
if (Window.ShowDetailedRoutingLogs)
{
string nextAction, outputPort, outputLabel;
nextAction = currentNHLFE.NextID == null ? "NULL" : currentNHLFE.NextID.ToString();
outputPort = currentNHLFE.OutPort == null ? "NULL" : currentNHLFE.OutPort.ToString();
outputLabel = currentNHLFE.OutLabel == null ? "NULL" : currentNHLFE.OutLabel.ToString();
AddLog($"Action for NHLFE_ID={currentNHLFE.ID} is {currentNHLFE.Action}, output port: {outputPort}, output label: {outputLabel}, next NHLFE_ID: {nextAction}", LogType.Information, Window.ShowDetailedRoutingLogs);
}
var thereIsNextAction = currentNHLFE.NextID != null;
PerformLabelAction(package, currentNHLFE, labelTTL, ref poppedLabelStack);
// after doing SWAP, the next action will be delivered via NEXT_ID, not ILM entry. Same thing for PUSH.
// if there is no next action id, then it means that we can forward the packet
if (!thereIsNextAction && (currentNHLFE.Action.Equals("SWAP") || currentNHLFE.Action.Equals("PUSH")))
{
AddLog($"Completed last action, forwarding to port {package.Port}", LogType.Information, Window.ShowDetailedRoutingLogs);
return(package);
}
// this means that we popped a label and the next action - push or swap - will be determined via ILM entry
if (!thereIsNextAction)
{
break;
}
currentNHLFE = RoutingTables.nhlfeTable.Rows.FirstOrDefault(row => row.ID == currentNHLFE.NextID);
}
}
}
private void HandlePackage(MPLSPackage package)
{
MPLSPackage routedPackage = null;
routedPackage = packageSwitch.RouteMPLSPackage(package, networkNodeRoutingTables, Window);
if (routedPackage == null)
{
return;
}
try
{
ConnectedSocket.Send(routedPackage);
AddLog(
$"Package {package} routed to port {routedPackage.Port} with label {routedPackage.PeekTopLabel()?.Number.ToString() ?? "None"}",
LogType.Sent);
}
catch (Exception e)
{
AddLog($"Package {routedPackage} not sent correctly: {e.Message}", LogType.Error);
}
}