[Steve Karg <skarg@xxxxxxxxxxxxxxxxxxxxx>]

Hello Developers,

Regarding bug:
http://bugs.ethereal.com/bugzilla/show_bug.cgi?id=855

The BACnet BVLC decoding assumed that it was the only protocol using UDP 
port 0xBAC0, and the example message arrived on that port.

A valid BACnet BVLC should also have a valid type byte (0x81) and a 
valid function byte (0x00 - 0x0B).

The example message had the BVLC type byte of 0x04, which indicates that 
it is not a BACnet BVLC message.

The example message had a function byte of 0x00 which falls in the range 
of valid BVLC function bytes.

In the attached patch, I added a check for the BVLC type at the very 
beginning of the dissection, so now it dissects the payload as data if 
the BVLC type is invalid.  It also does not set the COL or INFO if the 
BVLC type is invalid, so the invalid message shows UDP and 
source/destination port in Info.

Is there a way to dump the message back into the dissection queue if the 
type and function of the BVLC fails, or is just dissecting the payload 
as data the best we can do in this case?

Best Regards,

Steve

Attachment: bvlc.patch.gz
Description: GNU Zip compressed data