// Encode is called by internal services if the BBMD is also an active device
public int Encode(byte[] buffer, int offset, BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions function, int msgLength, BacnetAddress address)
{
// offset always 0, we are the first after udp
First7BytesHeaderEncode(buffer, function, msgLength);
// BBMD service
if ((function == BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_ORIGINAL_BROADCAST_NPDU) && _bbmdFdServiceActivated)
{
var me = _myTransport.LocalEndPoint;
BacnetAddress bacme;
BacnetIpV6UdpProtocolTransport.Convert(me, out bacme);
Array.Copy(VMAC, bacme.VMac, 3);
Forward_NPDU(buffer, msgLength, false, me, bacme); // send to all BBMDs and FDs
return(7); // ready to send
}
if (function != BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_ORIGINAL_UNICAST_NPDU)
{
return(0); // ?
}
buffer[7] = address.VMac[0];
buffer[8] = address.VMac[1];
buffer[9] = address.VMac[2];
return(10); // ready to send
}
// Send ack
private void SendAddressResolutionAck(IPEndPoint sender, byte[] vMacDest, BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions function)
{
var b = new byte[10];
First7BytesHeaderEncode(b, function, 10);
Array.Copy(vMacDest, 0, b, 7, 3);
_myTransport.Send(b, 10, sender);
}
private void First7BytesHeaderEncode(byte[] b, BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions function, int msgLength)
{
b[0] = BVLL_TYPE_BACNET_IPV6;
b[1] = (byte)function;
b[2] = (byte)((msgLength & 0xFF00) >> 8);
b[3] = (byte)((msgLength & 0x00FF) >> 0);
Array.Copy(VMAC, 0, b, 4, 3);
}
// Decode is called each time an Udp Frame is received
public int Decode(byte[] buffer, int offset, out BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions function, out int msgLength,
IPEndPoint sender, BacnetAddress remoteAddress)
{
// offset always 0, we are the first after udp
// and a previous test by the caller guaranteed at least 4 bytes into the buffer
function = (BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions)buffer[1];
msgLength = (buffer[2] << 8) | (buffer[3] << 0);
if ((buffer[0] != BVLL_TYPE_BACNET_IPV6) || (buffer.Length != msgLength))
{
return(-1);
}
Array.Copy(buffer, 4, remoteAddress.VMac, 0, 3);
switch (function)
{
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_RESULT:
return(9); // only for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_ORIGINAL_UNICAST_NPDU:
return(10); // only for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_ORIGINAL_BROADCAST_NPDU:
// Send to FDs & BBMDs, not broadcast or it will be made twice !
if (_bbmdFdServiceActivated)
{
Forward_NPDU(buffer, msgLength, false, sender, remoteAddress);
}
return(7); // also for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_ADDRESS_RESOLUTION:
// need to verify that the VMAC is mine
if ((VMAC[0] == buffer[7]) && (VMAC[1] == buffer[8]) && (VMAC[2] == buffer[9]))
{
// coming from myself ? avoid loopback
if (!_myTransport.LocalEndPoint.Equals(sender))
{
SendAddressResolutionAck(sender, remoteAddress.VMac,
BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_ADDRESS_RESOLUTION_ACK);
}
}
return(0); // not for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_FORWARDED_ADDRESS_RESOLUTION:
// no need to verify the target VMAC, should be OK
SendAddressResolutionAck(sender, remoteAddress.VMac,
BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_ADDRESS_RESOLUTION_ACK);
return(0); // not for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_ADDRESS_RESOLUTION_ACK: // adresse conflict
if ((VMAC[0] == buffer[4]) && (VMAC[1] == buffer[5]) && (VMAC[2] == buffer[6]) && RandomVmac)
{
new Random().NextBytes(VMAC);
VMAC[0] = (byte)((VMAC[0] & 0x7F) | 0x40);
SendAddressResolutionRequest(VMAC);
}
return(0); // not for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_VIRTUAL_ADDRESS_RESOLUTION:
SendAddressResolutionAck(sender, remoteAddress.VMac,
BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_VIRTUAL_ADDRESS_RESOLUTION_ACK);
return(0); // not for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_VIRTUAL_ADDRESS_RESOLUTION_ACK:
return(0); // not for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_FORWARDED_NPDU:
if (_myTransport.LocalEndPoint.Equals(sender))
{
return(0);
}
// certainly TODO the same code I've put in the IPV4 implementation
if (_bbmdFdServiceActivated && (msgLength >= 25))
{
bool ret;
lock (_bbmds)
ret = _bbmds.Exists(items => items.Equals(sender)); // verify sender presence in the table
// avoid also loopback
if (ret) // message from a know BBMD address, sent to all FDs and broadcast
{
SendToFDs(buffer, msgLength); // send without modification
// Assume all BVLC_FORWARDED_NPDU are directly sent to me in the
// unicast mode and not by the way of the multicast address
// If not, it's not really a big problem, devices on the local net will
// receive two times the message (after all it's just WhoIs, Iam, ...)
IPEndPoint ep;
BacnetIpV6UdpProtocolTransport.Convert(_broadcastAdd, out ep);
_myTransport.Send(buffer, msgLength, ep);
}
}
return(25); // for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_REGISTER_FOREIGN_DEVICE:
if (_bbmdFdServiceActivated && (msgLength == 9))
{
var TTL = (buffer[7] << 8) + buffer[8]; // unit is second
RegisterForeignDevice(sender, TTL);
SendResult(sender, BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Results.SUCCESSFUL_COMPLETION); // ack
}
return(0); // not for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_DELETE_FOREIGN_DEVICE_TABLE_ENTRY:
return(0); // not for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_SECURE_BVLC:
return(0); // not for the upper layers
case BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Functions.BVLC_DISTRIBUTE_BROADCAST_TO_NETWORK: // Sent by a Foreign Device, not a BBMD
if (_bbmdFdServiceActivated)
{
// Send to FDs except the sender, BBMDs and broadcast
lock (_foreignDevices)
{
if (_foreignDevices.Exists(item => item.Key.Equals(sender))) // verify previous registration
{
Forward_NPDU(buffer, msgLength, true, sender, remoteAddress);
}
else
{
SendResult(sender, BacnetIpV6UdpProtocolTransport.BacnetBvlcV6Results.DISTRIBUTE_BROADCAST_TO_NETWORK_NAK);
}
}
}
return(0); // not for the upper layers
// error encoding function or experimental one
default:
return(-1);
}
}