// 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); } }