public void RemoveProvider(DataLinkProvider d)
{
//
// Remove the specified DLP
//
lock (dataLinkProviderList)
{
dataLinkProviderList.Remove(d);
}
}
//
// Procesing thread for incoming packets from the TNC. The TNC places a buffer
// containing the incoming data into the channel's receive queue. This routine pulls
// these frames from the queue for processing.
//
// Processing steps:
// - Parse the raw incoming frame into an HDLC buffer. This process
// removes the byte stuffing and verifies the packet CRC.
// - Find the Data Link Provider handling incoming data for the Station ID
// specified in the incoming address field of the packet. If no matching
// dlp is registered, then we simply drop the packet. (Future: we add in support
// for multi-cast packets, which will forward to all registered DLPs)
// - Place the frame, source, and buffer type into a packet object and place it into the
// receive queue of the target DLP.
//
void RecvFromPort()
{
Byte[] buf;
while (runState.Equals(RunState.Running))
{
try
{
buf = channel.Recv();
}
catch
{
continue;
}
if (buf == null)
{
continue;
}
//
// Parse raw buffer
//
AX25Frame.ParsedFrame pFrame = new AX25Frame.ParsedFrame(HDLCFramer.ParseHDLCFrame(buf));
AX25Frame.Packet pkt = new AX25Frame.Packet(
AX25Frame.Packet.PacketType.ParsedFrame,
AX25Frame.Packet.Source.Remote,
pFrame);
//
// Look for the DLP handling this packet destination
//
DataLinkProvider dlp = GetProvider(pFrame.frameInfo.staLink.destinationAddr.stationIDString);
if (dlp == null)
{
//
// Ignore the packet and Loop if we cannot find a provider for the incoming frame
// TODO - Add support for multi-cast
//
continue;
}
//
// Send up to the data link provider handling the specified StationID
//
dlp.dataLinkProviderQ.Enqueue(pkt);
}
}
DataLinkProvider AddProvider(DataLinkProvider d)
{
//
// Add a DLP to the list if it is not already there.
//
lock (dataLinkProviderList)
{
foreach (DataLinkProvider dlp in dataLinkProviderList)
{
if (dlp.localStationAddress.stationIDString.Equals(d.localStationAddress.stationIDString))
{
return(dlp); //Connection already exists, so return it instead
}
}
dataLinkProviderList.Add(d);
return(d);
}
}
public Connection GetConnectionByACKModeID(DataLinkProvider dlp, Int16 AckModeID)
{
//
// Routine to seach for either an incoming or outgoing Connection handling a specific StationLink.
// Returns null if no connection is found.
//
Connection retCon = null;
lock (dlp.connectionList)
{
foreach (Connection con in dlp.connectionList)
{
if (con.AckModeID == AckModeID)
{
retCon = con;
break;
}
}
}
return(retCon);
}
//#endregion
DataLinkProvider GetProvider(String StationID)
{
//
// Routine to seach for the DLP handling a given station callsign. Returns null if
// no provider is found.
//
DataLinkProvider retDlp = null;
lock (dataLinkProviderList)
{
foreach (DataLinkProvider dlp in dataLinkProviderList)
{
if (dlp.localStationAddress.stationIDString.Equals(StationID))
{
retDlp = dlp;
break;
}
}
}
return(retDlp);
}
void DigipeatCheckAndProcess(Frame.Packet packet)
{
DataLinkProvider dlp = null;
Int32 relayNum = 0;
Int32 relayCount = 0;
if (packet.receivedFrame != null)
{
if (packet.receivedFrame.decodeOK)
{
//
// Packet looks OK
//
Station sta = packet.receivedFrame.staLink;
if (sta.relayStation1.stationIDString.Length > 0)
{
relayCount++;
}
if (sta.relayStation2.stationIDString.Length > 0)
{
relayCount++;
}
if ((relayCount >= 1) && (sta.relayStation1.chBit == 0))
{
//
// Relay address 1 has not been repeated, so see if we have a DLP for it.
//
dlp = GetProvider(sta.relayStation1.stationIDString);
relayNum = 1;
}
else if ((relayCount >= 2) && (sta.relayStation2.chBit == 0))
{
//
// Relay address 2 has not been repeated, so see if we have a DLP for it.
//
dlp = GetProvider(sta.relayStation2.stationIDString);
relayNum = 2;
}
else
{
dlp = GetProvider(sta.destinationStation.stationIDString);
}
}
if (dlp != null)
{
//
// We have a provider, check whether this is a digi or if packet is at its final destination
//
if (relayNum == 0)
{
//
// All digipeating complete (if any) so send it up for processing
//
dlp.Send(packet);
}
else
{
//
// Need to digipeat it, so send it up for digipeating
//
dlp.Digipeat(packet, relayNum);
}
}
}
}
