/// <summary>
/// Deserializes the message from a buffer
/// </summary>
/// <param name="buffer">The buffer to deserialize from</param>
/// <param name="offset">The offset to begin deserializing</param>
/// <returns>The offset of the next byte in the buffer</returns>
public int Deserialize(byte[] buffer, int offset)
{
byte[] bytes = new byte[6];
for (int i = 0; i < bytes.Length; i++)
{
bytes[i] = buffer[offset++];
}
this.OriginalMac = new Mac(bytes, false);
return offset;
}
/// <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);
}
public NetgramReceivedMessage(byte portId, Mac source, BufferSegment segment)
{
this.PortId = portId;
this.Source = source;
this.Segment = segment;
}
/// <summary>
/// Processes a received bvlc message
/// </summary>
/// <param name="mac">The mac address of the device that sent the message</param>
/// <param name="message">The bvlc message</param>
/// <param name="buffer">The buffer containing the message content</param>
/// <param name="offset">The offset of the content within the message</param>
/// <param name="length">The length of the received datagram</param>
/// <returns>The inbound netgram to propagate, if any</returns>
private NetgramReceivedMessage _processMessage(Mac mac, IBvlcMessage message, byte[] buffer, int offset, int length)
{
switch(message.Function)
{
case FunctionCode.Result:
_processResult(mac, ((ResultMessage)message).Result);
break;
case FunctionCode.ForwardedNpdu:
mac = ((ForwardedNpduMessage)message).OriginalMac;
goto case FunctionCode.OriginalUnicastNpdu;
case FunctionCode.OriginalUnicastNpdu:
case FunctionCode.OriginalBroadcastNpdu:
return _createInboundNetgram(mac, buffer, offset, length);
}
return null;
}
/// <summary>
/// Processes a received result message
/// </summary>
/// <param name="mac">The mac address of the device that sent the message</param>
/// <param name="code">The result code of the message</param>
private void _processResult(Mac mac, ResultCode code)
{
// we only process certain results from the BBMD
if (mac == _bbmdMac)
{
if(code == ResultCode.Success && (_state == State.Registering || _state == State.Renewing))
{
Console.WriteLine("Register Success");
_state = State.Open;
_registrationTimeout = DateTime.UtcNow.Add(_options.RegistrationInterval);
}
}
}
/// <summary>
/// Creates the bbmd mac address
/// </summary>
private void _createBbmdMac()
{
var bbmdIps = Dns.GetHostAddresses(_options.BbmdHost);
if (bbmdIps.Length == 0)
{
throw new Exception("Could not resolve '" + _options.BbmdHost + "'");
}
var bbmdEp = new IPEndPoint(bbmdIps[0], _options.BbmdPort);
_bbmdMac = IPUtils.IPEndPointToMac(bbmdEp);
}
/// <summary>
/// Creates an inbound netgram
/// </summary>
/// <param name="mac">The mac address of the device that sent the netgram</param>
/// <param name="buffer">The buffer containing the netgram content</param>
/// <param name="offset">The offset of the netgram within the buffer</param>
/// <param name="length">The length of the received datagram</param>
private NetgramReceivedMessage _createInboundNetgram(Mac mac, byte[] buffer, int offset, int length)
{
return new NetgramReceivedMessage(
this.PortId,
mac,
new BufferSegment(buffer, offset, length));
}
/// <summary>
/// Constructs a new address instance
/// </summary>
/// <param name="network">The network number of the address</param>
/// <param name="mac">The mac address of the address</param>
public Address(ushort network, Mac mac)
{
this.Network = network;
this.Mac = mac;
}
/// <summary>
/// Called whenever a packet is captured on the capture device
/// </summary>
/// <param name="sender">The sender of the event</param>
/// <param name="e">The event args</param>
private void _onPacketArrival(object sender, CaptureEventArgs e)
{
// don't process any packet too short to not be valid
if (e.Packet.Data.Length < _minimumPacketLength)
return;
// don't process any packets sent by the local device
if (_isOutboundPacket(e.Packet.Data))
return;
byte[] buffer = e.Packet.Data;
int offset = 0;
Mac destination, source;
int length;
byte dsap, ssap, control;
destination = new Mac(buffer, offset, 6);
offset += 6;
source = new Mac(buffer, offset, 6);
offset += 6;
length = buffer.ReadUInt16(offset);
offset += 2;
dsap = buffer[offset++];
ssap = buffer[offset++];
control = buffer[offset++];
// don't process non-BACnet packets
if (dsap != 0x82 || ssap != 0x82 || control != 0x03)
return;
NetgramReceivedMessage message = new NetgramReceivedMessage(
this.PortId,
source,
new BufferSegment(buffer, offset, buffer.Length));
if (Session != null)
{
Session.QueueMessage(message);
}
}
/// <summary>
/// Adds a new remote route to routing table
/// </summary>
/// <param name="network">The network number of the route</param>
/// <param name="portId">The port id of the route</param>
/// <param name="nextHop">The next hop mac address</param>
public Route AddRemoteRoute(ushort network, byte portId, Mac nextHop)
{
int index = _findRoute(network);
return _upsertRoute(index, new Route(network, portId, nextHop));
}
/// <summary>
/// Constructs a new Route instance
/// </summary>
/// <param name="network">The network number of the route</param>
/// <param name="portId">The port id of the next hop port</param>
/// <param name="nextHop">The next hop mac address, or a broadcast address for a local port</param>
public Route(ushort network, byte portId, Mac nextHop)
{
this.Network = network;
this.PortId = portId;
this.NextHop = nextHop;
}
public NetgramReceivedMessage(byte portId, Mac source, BufferSegment segment)
{
this.PortId = portId;
this.Source = source;
this.Segment = segment;
}