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Wireshark-users: Re: [Wireshark-users] LUA set value for treeitem

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From: "Maynard, Chris" <Christopher.Maynard@xxxxxxx>
Date: Thu, 20 Sep 2018 14:50:04 +0000

I guess I misunderstood what you were trying to do.

 

Given:

 

n  Myproperty

o   X.409 Integer

§  Tag

§  Length

§  Value

 

I thought you just wanted a way to display the “Value” on the “Myproperty” row but that since you already added “Value” to the tree, can’t you simply filter on the “Value” field, i.e., instead of a filter like myprop.myproperty==0xFF, use something like myprop.myproperty.x509integer.value==0xFF?

 

If you really want to be able to apply a filter like myprop.myproperty==0xFF, then I think you’ll have to delay adding it to the tree until after you’ve dissected the “Value”, and then add it something like so:

 

local myproperty_tree = tree:add(pf_myproperty, buffer(offset, len), value)

Note here that since you’ve dissected the value, you must already know the len, so you ought to be able to use len and there should be no need to call set_len() later.

- Chris

 

From: Wireshark-users [mailto:wireshark-users-bounces@xxxxxxxxxxxxx] On Behalf Of Pawlowsky, Marc
Sent: Thursday, September 20, 2018 8:59 AM
To: wireshark-users@xxxxxxxxxxxxx
Subject: Re: [Wireshark-users] LUA set value for treeitem

 

Setting the text changes the display but does not appear to allow for the item to be filtered on.

 

 

Date: Wed, 19 Sep 2018 18:05:28 +0000
From: "Maynard, Chris" <Christopher.Maynard@xxxxxxx>
To: Community support list for Wireshark
<wireshark-users@xxxxxxxxxxxxx>
Subject: Re: [Wireshark-users] LUA set value for treeitem
Message-ID:
<67a8dad7ac044e7989c93f106d68ee07@xxxxxxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset="utf-8"

Yes, you can set the value using myproperty_tree:set_text(somestring)

For example: myproperty_tree:set_text(string.format("myproperty: 0x%02X", someval))

See Section 11.7.1.4 of the Wireshark Developer's Guide[1].
- Chris
[1]: https://www.wireshark.org/docs/wsdg_html_chunked/lua_module_Tree.html#lua_class_TreeItem


From: Wireshark-users [mailto:wireshark-users-bounces@xxxxxxxxxxxxx] On Behalf Of Pawlowsky, Marc
Sent: Wednesday, September 19, 2018 9:46 AM
To: wireshark-users@xxxxxxxxxxxxx<mailto:wireshark-users@xxxxxxxxxxxxx>
Subject: [Wireshark-users] LUA set value for treeitem

Is there a way to set the value for a treeitem after the tree item has been created?

The problem:

I am writing a X.409 based decoder (similar ASN.1).

I have a property stored as an integer to decode.
I come up with a tree like:

n Myproperty
o X.409 Integer
? Tag
? Length
? Value


The length of the value field is variable.

I have a protofield for all treeitems.
For my property I am currently using
pf_myproperty = ProtoField.uint8("myprop.myproperty ", "myproperty", base.HEX)

I create the myproperty treeitem first, then drill down and create the treeitems underneath it.
To prevent the protofield from decoding nonsense I am setting the value explicitly
local myproperty_tree = tree:add(pf_myproperty, buffer(offset), 0)

After all the tree items are created I can set the length using myproperty_tree::set_len(len)

Is there a way I can set the value after creation?

I want to be able to filter on myproperty.
Something like myprop.myproperty==0xFF

I cannot find anything in
https://www.wireshark.org/docs/wsdg_html_chunked/lua_module_Tree.html


Thanks
Marc

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