Hello, I am writting a lua dissector (on top of UDP) and I need to use the vlan tag from the 802.1Q virtual lan layer. I can see the vlan I tried to extract the vlan tag like I extract the source address pinfo.cols.src. pinfo.cols.vlan is null in the coulmns in the GUI I can see the vlan tag correctly.
How do I get the vlan tag?
The VLAN Display Filter Reference page lists several VLAN-related fields. You can access any of them from your Lua dissector with something like so:
-- Ref: https://www.wireshark.org/docs/wsdg_html/#wsluarm_modules
local foo = Proto("FOO", "Foo")
local foo_vlan_id = ProtoField.uint16("foo.vlan_id", "VLAN ID")
-- Section 11.2.1.1: Use Field extractor to grab field of interest
local vlan_id = Field.new("vlan.id")
function foo.dissector(tvbuf, pinfo, tree)
local foo_tree = tree:add(foo, "Foo")
foo_tree:add(foo_vlan_id, vlan_id().value)
end
Asked: 2021-08-11 09:00:31 +0000
Seen: 632 times
Last updated: Aug 12 '21