Re: [iptables PATCH] iptables: xshared: Ouptut '--' in the opt field in ipv6's fake mode

[Jan Engelhardt <jengelh@inai.de>]

On Wednesday 2022-07-20 15:06, Erik Skultety wrote:

>The fact that the 'opt' table field reports spaces instead of '--' for
>IPv6 as it would have been the case with IPv4 has a bit of an
>unfortunate side effect that it completely confuses the 'jc' JSON
>formatter tool (which has an iptables formatter module).
>Consider:
>    # ip6tables -L test
>    Chain test (0 references)
>    target     prot opt source   destination
>    ACCEPT     all      a:b:c::  anywhere    MAC01:02:03:04:05:06
>
>Then:
>    # ip6tables -L test | jc --iptables
>    [{"chain":"test",
>      "rules":[
>          {"target":"ACCEPT",
>           "prot":"all",
>           "opt":"a:b:c::",
>           "source":"anywhere",
>           "destination":"MAC01:02:03:04:05:06"
>          }]
>    }]
>
>which as you can see is wrong simply because whitespaces are considered
>as a column delimiter.

Even if you beautify the opt column with a dash, you still have
problems elsewhere. "MAC01" for example is not the destination
at all.

If you or jc is to parse anything, it must only be done with the
iptables -S output form.