private void HandleRouteError(
MacAddress srcAddr,
MacAddress dstAddr,
ref Frame sdu)
{
Message.RouteError re = new Message.RouteError();
if (re.ReadFromFrame(sdu))
{
// check message
Trace.Print("Received " + re.ToString());
if (re.UnreachableAddr != cInvalidShortAddr && srcAddr.Mode == MacAddressingMode.ShortAddress)
{
bool validRoute = _routingTable.HandleRouteError(re.UnreachableAddr, srcAddr.ShortAddress, re.FatalError);
if (validRoute)
{
if (re.TargetAddr == _addrShort)
{ // sent to us
SendRouteRequest(re.UnreachableAddr);
}
else
{ // forward error
if (re.HopsLeft > 0)
{
re.HopsLeft--;
SendRouteError(re);
}
}
}
}
}
}
private void SendRouteError(
UInt16 tgtAddr,
UInt16 unrAddr,
bool fatalError)
{
Message.RouteError re = new Message.RouteError();
re.FatalError = fatalError;
re.HopsLeft = cDefaultHopLimit; // time-to-live, drop when 0
re.TargetAddr = tgtAddr;
re.OriginatorAddr = _addrShort;
re.UnreachableAddr = unrAddr;
SendRouteError(re);
}
private void SendRouteError(Message.RouteError re)
{
Frame frame = Frame.GetFrame(_macHeader + Message.RouteError.cLength + _macTailer);
if (frame == null)
return;
frame.ReserveHeader(_macHeader);
if (re.WriteToFrame(frame))
{
UInt16 nextHop;
if (_routingTable.GetRoute(re.TargetAddr, out nextHop))
{
MacDataRequest(nextHop, ref frame);
}
}
Frame.Release(ref frame);
}
