Wireshark · Wireshark-dev: Re: [Wireshark-dev] Registering header fields later/in other functions?

[Andreas <AndreasSander1@xxxxxxx>]

Am 12.02.2011 22:32, schrieb Thomas Wiens:
> Hi,
>
> I am developing a custom dissector in C.
> For clearness I want to put parts of the dissector in different source
> files.
>
> The problem I have, is that the header fields have to be registered
> directly after the proto_register_protocol() call.
> It would be nice if it would be possible to declare and register the
> header fields only in the sourcefile where they are used.
> Is there a way to do this?
>
> Example (the main hf struct-array was registered before):
> gint hf_pr = -1;
> hf_register_info hf = { &hf_pr,
> { "index", "s7comm.szl_0131_2", FT_UINT16, BASE_HEX, NULL, 0x0, "SZL ID
> 0x0131 Index 2: index", HFILL }
> };
> // is it possible to register header field here?
> proto_tree_add_uint(tree, hf_pr, tvb, offset, 2, tvb_get_ntohs(tvb,
> offset));
>
> I don't need to filter on these entries, but I want to use the nicer
> display features I have with the header fields (e.g. comments in status
> bar).
> At this time I'm using the proto_tree_add_text() in my 'outsourced'
> functions to display the dissected items.

I have dissectors classes that are spreaded over a lot of source files. 
When Wireshark calls the function plugin_register() of my dissector, all 
classes' Register() functions are called. So there is no problem with 
making a dissector modular.

Registering the header fields on demand, before calling the 
proto_tree_add_xxx might work, but you need to handle the state 
"registered". Therefore you should register it, when Wireshark calls you 
for it.

--
Andy