// Encode is called by internal services if the BBMD is also an active device
public int Encode(byte[] buffer, int offset, BacnetBvlcV6Functions function, int msg_length, BacnetAddress address)
{
// offset always 0, we are the first after udp
First7BytesHeaderEncode(buffer, function, msg_length);
// BBMD service
if ((function == BacnetBvlcV6Functions.BVLC_ORIGINAL_BROADCAST_NPDU) && (BBMD_FD_ServiceActivated == true))
{
IPEndPoint me = MyTransport.LocalEndPoint;
BacnetAddress Bacme;
BacnetIpV6UdpProtocolTransport.Convert(me, out Bacme);
Array.Copy(VMAC, Bacme.VMac, 3);
Forward_NPDU(buffer, msg_length, false, me, Bacme); // send to all BBMDs and FDs
return(7); // ready to send
}
if (function == BacnetBvlcV6Functions.BVLC_ORIGINAL_UNICAST_NPDU)
{
buffer[7] = address.VMac[0];
buffer[8] = address.VMac[1];
buffer[9] = address.VMac[2];
return(10); // ready to send
}
return(0); // ?
}
// Never tested
private void Forward_NPDU(byte[] buffer, int msg_length, bool ToGlobalBroadcast, IPEndPoint EPsender, BacnetAddress BacSender)
{
// Forms the forwarded NPDU from the original (broadcast npdu), and send it to all
// copy, 18 bytes shifted (orignal bvlc header : 7 bytes, new one : 25 bytes)
byte[] b = new byte[msg_length + 18]; // normaly only 'small' frames are present here, so no need to check if it's to big for Udp
Array.Copy(buffer, 0, b, 18, msg_length);
// 7 bytes for the BVLC Header, with the embedded 6 bytes IP:Port of the original sender
First7BytesHeaderEncode(b, BacnetBvlcV6Functions.BVLC_FORWARDED_NPDU, msg_length + 18);
// replace my Vmac by the orignal source vmac
Array.Copy(BacSender.VMac, 0, b, 4, 3);
// Add IpV6 endpoint
Array.Copy(BacSender.adr, 0, b, 7, 18);
// Send To BBMD
SendToBBMDs(b, msg_length + 18);
// Send To FD, except the sender
SendToFDs(b, msg_length + 18, EPsender);
// Broadcast if required
if (ToGlobalBroadcast == true)
{
IPEndPoint ep;
BacnetIpV6UdpProtocolTransport.Convert(BroadcastAdd, out ep);
MyTransport.Send(b, msg_length + 18, ep);
}
}
// quite the same frame as the previous one
private void SendAddressResolutionRequest(byte[] VMacDest)
{
IPEndPoint ep;
BacnetIpV6UdpProtocolTransport.Convert(BroadcastAdd, out ep);
byte[] b = new byte[10];
First7BytesHeaderEncode(b, BacnetBvlcV6Functions.BVLC_ADDRESS_RESOLUTION, 10);
Array.Copy(VMacDest, 0, b, 7, 3);
MyTransport.Send(b, 10, ep);
}
// Decode is called each time an Udp Frame is received
public int Decode(byte[] buffer, int offset, out BacnetBvlcV6Functions function, out int msg_length, IPEndPoint sender, BacnetAddress remote_address)
{
// 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 = (BacnetBvlcV6Functions)buffer[1];
msg_length = (buffer[2] << 8) | (buffer[3] << 0);
if ((buffer[0] != BVLL_TYPE_BACNET_IPV6) || (buffer.Length != msg_length))
{
return(-1);
}
Array.Copy(buffer, 4, remote_address.VMac, 0, 3);
switch (function)
{
case BacnetBvlcV6Functions.BVLC_RESULT:
return(9); // only for the upper layers
case BacnetBvlcV6Functions.BVLC_ORIGINAL_UNICAST_NPDU:
return(10); // only for the upper layers
case BacnetBvlcV6Functions.BVLC_ORIGINAL_BROADCAST_NPDU:
// Send to FDs & BBMDs, not broadcast or it will be made twice !
if (BBMD_FD_ServiceActivated == true)
{
Forward_NPDU(buffer, msg_length, false, sender, remote_address);
}
return(7); // also for the upper layers
case 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, remote_address.VMac, BacnetBvlcV6Functions.BVLC_ADDRESS_RESOLUTION_ACK);
}
}
return(0); // not for the upper layers
case BacnetBvlcV6Functions.BVLC_FORWARDED_ADDRESS_RESOLUTION:
// no need to verify the target VMAC, should be OK
SendAddressResolutionAck(sender, remote_address.VMac, BacnetBvlcV6Functions.BVLC_ADDRESS_RESOLUTION_ACK);
return(0); // not for the upper layers
case 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 BacnetBvlcV6Functions.BVLC_VIRTUAL_ADDRESS_RESOLUTION:
SendAddressResolutionAck(sender, remote_address.VMac, BacnetBvlcV6Functions.BVLC_VIRTUAL_ADDRESS_RESOLUTION_ACK);
return(0); // not for the upper layers
case BacnetBvlcV6Functions.BVLC_VIRTUAL_ADDRESS_RESOLUTION_ACK:
return(0); // not for the upper layers
case BacnetBvlcV6Functions.BVLC_FORWARDED_NPDU:
if (MyTransport.LocalEndPoint.Equals(sender))
{
return(0);
}
// certainly TODO the same code I've put in the IPV4 implementation
if ((BBMD_FD_ServiceActivated == true) && (msg_length >= 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, msg_length); // 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, msg_length, ep);
}
}
return(25); // for the upper layers
case BacnetBvlcV6Functions.BVLC_REGISTER_FOREIGN_DEVICE:
if ((BBMD_FD_ServiceActivated == true) && (msg_length == 9))
{
int TTL = (buffer[7] << 8) + buffer[8]; // unit is second
RegisterForeignDevice(sender, TTL);
SendResult(sender, BacnetBvlcV6Results.SUCCESSFUL_COMPLETION); // ack
}
return(0); // not for the upper layers
case BacnetBvlcV6Functions.BVLC_DELETE_FOREIGN_DEVICE_TABLE_ENTRY:
return(0); // not for the upper layers
case BacnetBvlcV6Functions.BVLC_SECURE_BVLC:
return(0); // not for the upper layers
case BacnetBvlcV6Functions.BVLC_DISTRIBUTE_BROADCAST_TO_NETWORK: // Sent by a Foreign Device, not a BBMD
if (BBMD_FD_ServiceActivated == true)
{
// 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, msg_length, true, sender, remote_address);
}
else
{
SendResult(sender, BacnetBvlcV6Results.DISTRIBUTE_BROADCAST_TO_NETWORK_NAK);
}
}
}
return(0); // not for the upper layers
// error encoding function or experimental one
default:
return(-1);
}
}