private void DecodeConfirmedService(byte[] apdu_buf)
{
if ((apdu_buf[0] & 0x08) != 0)
{
_apm.MessageTodo("m0002 Need to implement confirmed service types with seg=1 still");
return;
}
int iptr = 3;
confirmedServiceChoice = (BACnetEnums.BACNET_CONFIRMED_SERVICE)apdu_buf[iptr++];
apduConfirmedServiceTypeFlag = true;
switch (confirmedServiceChoice)
{
case BACnetEnums.BACNET_CONFIRMED_SERVICE.SERVICE_CONFIRMED_READ_PROPERTY:
// Expecting 2-3 context tags.
// First, mandatory, context 0, object ID
objectID = new BACnetObjectIdentifier();
objectID.DecodeContextTag(apdu_buf, ref iptr);
// Second, mandatory, Property ID
propertyID = (BACnetEnums.BACNET_PROPERTY_ID)BACnetEncoding.DecodeTagContextUint(apdu_buf, ref iptr, 1);
// Third, Array Index, Optional
if (iptr < apdu_length)
{
arrayIndex = (int)BACnetEncoding.DecodeTagContextUint(apdu_buf, ref iptr, 2);
arrayIndexDecoded = true;
}
break;
default:
_apm.MessageTodo("m0024 all the other service types");
break;
}
}
void DecodeComplexACK(byte[] buf, int offset)
{
if ((buf[offset] & 0x0f) != 0)
{
throw new Exception("m0020 - Not ready to handle segmented messages yet");
}
// invoke ID - ignoring for now
// Service ACK choice
BACnetEnums.BACNET_CONFIRMED_SERVICE sc = (BACnetEnums.BACNET_CONFIRMED_SERVICE)buf[offset + 2];
switch (sc)
{
case BACnetEnums.BACNET_CONFIRMED_SERVICE.SERVICE_CONFIRMED_READ_PROPERTY:
offset += 3;
// Decode Object ID of the object whos property we are reading
BACnetObjectIdentifier oid = new BACnetObjectIdentifier(buf, ref offset, BACnetEnums.TAG.CONTEXT, 0);
// Decode the property ID
propertyID = (BACnetEnums.BACNET_PROPERTY_ID)BACnetEncoding.DecodeTagContextUint(buf, ref offset, 1);
// Now decode the Property Value itself. Variable encoding, variable length, etc....
switch (oid.objectType)
{
case BACnetEnums.BACNET_OBJECT_TYPE.OBJECT_DEVICE:
switch (propertyID)
{
case BACnetEnums.BACNET_PROPERTY_ID.PROP_OBJECT_LIST:
// decode the list of objects
// process the opening context tag, 0x3e
if (buffer[offset++] != 0x3e)
{
throw new Exception("m0033 - Opening context tag not found " + buffer[offset - 1].ToString());
}
objectList = new List <BACnetObjectIdentifier>();
// now loop until closing tag found
while (buffer[offset] != 0x3f)
{
// we should get a list of object IDs, add these to our backnet packet object as they are discovered.
objectList.Add(new BACnetObjectIdentifier(buffer, ref offset, BACnetEnums.TAG.APPLICATION, BACnetEnums.BACNET_APPLICATION_TAG.BACNET_APPLICATION_TAG_OBJECT_ID));
}
break;
case BACnetEnums.BACNET_PROPERTY_ID.PROP_OBJECT_NAME:
_apm.MessageTodo("m0032 - Decode object name");
break;
default:
_apm.MessageTodo("m0026 Unimplemented Property ID " + propertyID.ToString());
break;
}
break;
default:
_apm.MessageTodo("m0061 Unhandled object type " + oid.objectType.ToString());
break;
}
break;
default:
_apm.MessageTodo("m0028 - Not ready to deal with this service yet " + sc.ToString());
return;
}
}
private bool DecodeUnconfirmedService(byte[] apdu_buf, int apduLen)
{
// todo, this code assumes that the service is encoded in postion number one. This is not always the case. Resolve
if ((apdu_buf[0] & 0x0f) != 0)
{
_apm.MessageProtocolError("m0025 this nibble should be zero for Unconfirmed services");
return(false);
}
if (apdu_buf[1] == (byte)BACnetEnums.BACNET_UNCONFIRMED_SERVICE.SERVICE_UNCONFIRMED_WHO_IS)
{
// http://www.bacnetwiki.com/wiki/index.php?title=Who-Is
apduUnconfirmedServiceFlag = true;
unconfirmedServiceChoice = BACnetEnums.BACNET_UNCONFIRMED_SERVICE.SERVICE_UNCONFIRMED_WHO_IS;
if (apduLen != 2)
{
int offset = 2;
// means we must have a low and high range..
lowRange = BACnetEncoding.DecodeTagContextUint(apdu_buf, ref offset, 0);
highRange = BACnetEncoding.DecodeTagContextUint(apdu_buf, ref offset, 1);
}
// and for now, we will assume only workstations issue who-is messages.
this.srcDevice.type = BACnetEnums.DEVICE_TYPE.Workstation;
}
else if (apdu_buf[1] == (byte)BACnetEnums.BACNET_UNCONFIRMED_SERVICE.SERVICE_UNCONFIRMED_I_AM)
{
apduUnconfirmedServiceFlag = true;
unconfirmedServiceChoice = BACnetEnums.BACNET_UNCONFIRMED_SERVICE.SERVICE_UNCONFIRMED_I_AM;
// I-Am described right here: http://www.bacnetwiki.com/wiki/index.php?title=I-Am
// first encoded entity is the Device Identifier...
// Encoding described here: http://www.bacnetwiki.com/wiki/index.php?title=Encoding
// Decode Device Identifier
int offset = 2;
srcDevice.deviceObjectID.DecodeApplicationTag(apdu_buf, ref offset);
Console.WriteLine("This is device: " + srcDevice.deviceObjectID);
// todo, for now, we will ignore device insance xxx if received
// and we are the client (bacnet browser )
srcDevice.packet = this;
uint maxAPDULen;
offset += BACnetEncoding.BACnetDecode_uint(apdu_buf, offset, out maxAPDULen);
Console.WriteLine("Max APDU length accepted: " + maxAPDULen);
uint segmentation_supported;
offset += BACnetEncoding.BACnetDecode_uint(apdu_buf, offset, out segmentation_supported);
Console.WriteLine("Segmentation Supported: " + segmentation_supported);
srcDevice.SegmentationSupported = (BACnetEnums.BACNET_SEGMENTATION)segmentation_supported;
uint vendorId;
offset += BACnetEncoding.BACnetDecode_uint(apdu_buf, offset, out vendorId);
Console.WriteLine("VendorId: " + vendorId);
srcDevice.VendorId = vendorId;
}
return(true);
}