Re: Migrating dissector to WS 1.12

[Pascal Quantin <pascal.quantin () gmail com>]

2015-05-20 20:15 GMT+02:00 Helge Kruse <Helge.Kruse () gmx net>:

> Hi Pascal,
>
>
>
> at first I’ve spotted two additional functions that are missing or have
> changed the semantic.
>
>
>
> In old dissector I have a construct
>
>        if (check_col(m_pinfo->cinfo, COL_PROTOCOL))
>
>        {      // column is displayed
>
>              col_set_str(m_pinfo->cinfo, COL_PROTOCOL, "my protocol");
>
>        }
>
>
>
> The check_col function is not available anymore. How to fill the protocol
> column.

You can remove the check_col function call completely: the col_XXX
functions handle automatically whether the column is present of not.


> And the second question is about TCP stream dissection. The function
> tcp_dissect_pdus has changed parameters and the signature of
> new_dissector_t isn’t clear. Wasn’t it the job of the get_pdu_len
> function to get the correct number of byte of a pdu?

I guess you are referring to the return value of new_dissector_t.  Keep in
mind that dissectors are also used outside of tcp_dissect_pdus() call.
Moreover this new signature adds an extra parameter allowing you to give
eventually extra info to the sub dissector.
Changing dissector from dissector_t to new_dissector_t is quite
straightforward. At the end of the dissection, you can simply do a "return
tvb_captured_length(tvb);" and change the registration routine from
register_dissector() to new_register_dissector().


> Best regards
>
> Helge
>
>
>
> *From:* wireshark-dev-bounces () wireshark org [mailto:
> wireshark-dev-bounces () wireshark org] *On Behalf Of *Pascal Quantin
> *Sent:* Wednesday, May 20, 2015 7:04 PM
> *To:* Developer support list for Wireshark
> *Subject:* Re: [Wireshark-dev] Migrating dissector to WS 1.12
>
>
>
> Hi Helge,
>
>
>
> 2015-05-20 18:46 GMT+02:00 Helge Kruse <Helge.Kruse () gmx net>:
>
> Hi,
>
> I am migrating from WS 1.6 to WS 1.12 skipping all version between.
> I have some code that uses functions that are not available in the
> current version. How can I find how this functions are replaced by newer
> functions?
>
> Example: tvb_get_ephemeral_string()
>
>
>
> This one is replaced by
> tvb_get_string_enc(wmem_packet_scope(),tvb,offset,length, ENC_ASCII |
> ENC_NA);
>
> Conversions from older to newer APIs are not veery well documented
> unfortunately. You can easily find them by doing searches in git hitory, or
> if the list is not too long you can ask on this mailing list.
>
> Regards,
>
> Pascal.
>
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