/// <summary>
/// Called whenever a datagram is received
/// </summary>
/// <param name="ep">The IPEndPoint of the sending device</param>
/// <param name="buffer">The buffer containing the datagram</param>
/// <param name="length">The length of the received datagram</param>
/// <returns>The inbound netgram to propagate, if any</returns>
private void _onDatagramReceived(IPEndPoint ep, byte[] buffer, int length)
{
int offset = 0;
BvlcHeader header = null;
IBvlcMessage message = null;
NetgramReceivedMessage netgram = null;
Mac mac = IPUtils.IPEndPointToMac(ep);
try
{
if (length < 4)
throw new Exception("Received datagram under 4 bytes long");
header = new BvlcHeader();
offset = header.Deserialize(buffer, offset);
if (header.Length != length)
throw new Exception("Received bvlc datagram with non-matching lengths");
message = _createMessage(header.Function);
offset = message.Deserialize(buffer, offset);
lock (_lock)
{
netgram = _processMessage(mac, message, buffer, offset, length);
}
if (netgram != null && Session != null)
Session.QueueMessage(netgram);
}
catch(Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
/// <summary>
/// Sends a bvlc message
/// </summary>
/// <param name="mac">The BACnet mac address of the destination device</param>
/// <param name="message"></param>
private void _sendMessage(Mac mac, IBvlcMessage message)
{
// TODO: constant for buffer size, or
// lease buffers from the UDPAsyncServer instance
IPEndPoint ep = IPUtils.MacToIPEndPoint(mac);
byte[] buffer = new byte[1500];
int offset = 0;
BvlcHeader header = null;
header = new BvlcHeader();
header.Function = message.Function;
header.Length = 0;
offset = header.Serialize(buffer, offset);
offset = message.Serialize(buffer, offset);
// patch the length in now that it is known
buffer[2] = (byte)(offset << 8);
buffer[3] = (byte)(offset);
_server.Send(ep, buffer, offset);
}
/// <summary>
/// Sends a netgram out of this port
/// </summary>
/// <param name="netgram">The netgram to send</param>
public void SendNetgram(OutboundNetgram netgram)
{
IPEndPoint ep = null;
byte[] buffer = new byte[1500];
int offset = 0;
BvlcHeader header = new BvlcHeader();
IBvlcMessage message = null;
if (netgram.Destination.IsBroadcast())
{
ep = IPUtils.MacToIPEndPoint(_bbmdMac);
header.Function = FunctionCode.OriginalUnicastNpdu;
//header.Function = FunctionCode.OriginalBroadcastNpdu;
header.Length = 0;
message = new OriginalBroadcastNpduMessage();
}
else
{
ep = IPUtils.MacToIPEndPoint(netgram.Destination);
header.Function = FunctionCode.OriginalUnicastNpdu;
header.Length = 0;
message = new OriginalUnicastNpduMessage();
}
offset = header.Serialize(buffer, offset);
offset = message.Serialize(buffer, offset);
offset = netgram.Content.Serialize(buffer, offset);
// patch the length
buffer[2] = (byte)(offset << 8);
buffer[3] = (byte)(offset);
lock(this._lock)
{
if (_server != null)
{
_server.Send(ep, buffer, offset);
}
}
}
