Wireshark-dev: Re: [Wireshark-dev] Support for ASN.1 ECN in asn2wrs
From: "Kukosa, Tomas" <tomas.kukosa@xxxxxxxxxxx>
Date: Tue, 24 Feb 2009 09:37:54 +0100
Hi,

there is not plan to do it now.

The 1st step should be to define ECN in Wireshark C code somehow.
When we have it prepared then the asn2wrs can generate code for it.

My raw idea is:
- new packet-ecn.c similar to packet-per.c and packet-ber.c will be
introduced
- define new interface (set of functions) between packet-ecn.c and
concrete ECN implementation
- the packet-ecn.c will call user defined ECN implementation saved in
asn1_ctx during decoding

The code using ECN could look like:

static asn1_ecn_impl_t my_impl = {
  my_decode_integer,
  my_decode_boolean,
  ...
}

asn1_ctx_init(&asn1_ctx, ASN1_ENC_ECN, TRUE, pinfo);
asn1_ctx_set_ecn(&asn1_ctx, &my_impl)
dissect_my_Pdu(tvb, offset, &asn1_ctx, ...


Best regards,
  Tomas
 

> -----Original Message-----
> From: wireshark-dev-bounces@xxxxxxxxxxxxx 
> [mailto:wireshark-dev-bounces@xxxxxxxxxxxxx] On Behalf Of 
> Olivier Willot
> Sent: Tuesday, February 24, 2009 8:58 AM
> To: wireshark-dev@xxxxxxxxxxxxx
> Subject: [Wireshark-dev] Support for ASN.1 ECN in asn2wrs
> 
> Hi
> 
> Is there any plan to add support of Encoding Control Notation in  
> asn2wrs? That would allow to easily add support for non ASN.1 based  
> protocols without needing to hand-code a dissector.
> 
> In the mean-time, any workaround ( custom wireshark specific 
> encoding  
> for instance )?
> 
> I need to develop dissectors for ASCII based application 
> protocols and  
> some packed binary structs based ones as well.
> I seems that for ASCII based ones, using IA5 strings only with  
> standard PER encoding could do it, but I would like to be sure under  
> which conditions PER will encode my field with a TLV triplet 
> and under  
> which condition I can be sure it will only write the field 
> value with  
> no prefix.
> Do you have an example of ASCII based protocol which abstract syntax  
> exactly matches the corresponding C structure? Using Which encoding?
> 
> Thanks
> Olivier
> 
> 
>   
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