[Matthijs Melchior <mmelchior@xxxxxxxxx>]

Alexander,

Alexander W. Janssen wrote:

> Hello,
>
> my company has a lot of protocols where the full definition is available in
> ASN.1. The messages are BER encoded. I found out that ethereal has some sort
> of BER decoder and i wonder how to use or extend it to support our own
> protocols.
>
> So, my question is: Is there a ASN.1 interpreter (subsequent to the BER
> decoder) included? If not, how do i bash my own ASN.1 definitions into that
> framework? I was thinking about pushing the definitions through a asn.1
> compiler and hack the output into some sort of framework which fits into that
> asn.1 stuff in Ethereal.
>
> Are there more specific pointers about that subject?
>  
The ethereal ASN.1 dissector uses a type-table to describe the ASN.1 types
and values.  This type-table is generated by 'snacc', a free ASN.1 compiler
suite, and in the configuration pane for the dissector you point it to such
a .tt file and mention the name of the top-level PDU and the port where
to expect these messages in a data stream.

Ethereal will than display the ASN.1 messages with values annotated with
their types and names.

I use the Debian package to provide me with snacc[1.3bbn-5], use google
to find other instances of snacc.

The source file for this dissector, plugins/asn1/packet-asn1.c in the
ethereal tree, contains some more documentation.

--
Regards,
----------------------------------------------------------------  -o)
Matthijs Melchior                                       Maarssen  /\\
mmelchior@xxxxxxxxx                                  Netherlands _\_v
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