I want to set 'destination' column to a string. I tried following but it did not help.
pinfo.cols.dst = "Hello"
Can it be done?
It works for 'info' column as follows:
pinfo.cols.info = "Hello"
I think this is a bug. You could open a Gitlab Issue asking that it be looked into. (please add a link back to this question if you do)
For testing, opening a non-IP file (small-system-misc-ping.etl (MS ETL) Various events, ping and browser packets.) from Wiki samples with etwdump allows the field to be set.
For an IP capture, disable the ethernet protocol and see Destination column updated by Lua.
I think this is caused by epan_dissect_fill_in_columns() which calls col_fill_in().
The Destination column is populated with pinfo.dst which contains the value set by the last dissector to touch it. The column then shows the highest level "destination" address in the protocol stack.
You can test in the Lua script by printing pinfo.cols.dst after changing it:
pinfo.cols.dst:append("Hello")
print("dst2=","(",pinfo.cols.dst,")")
It then gets walloped later by epan_dissect_fill_in_columns().
pinfo.dst is an Address object in Lua and there isn't a way to clear it or set it to a string.
Comments
It should work -- I have a Lua plugin that does it successfully using exactly the code you posted.
Could you try to put together a smallest possible example of what doesn't work?