From: Florian Westphal <fw@strlen.de>
To: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Cc: netfilter-devel@vger.kernel.org, pablo@netfilter.org, fw@strlen.de
Subject: Re: [iptables PATCH v3 2/2] extensions: libxt_conntrack: print xlate status as set
Date: Wed, 31 Mar 2021 12:58:52 +0200 [thread overview]
Message-ID: <20210331105852.GD17285@breakpoint.cc> (raw)
In-Reply-To: <20210331102934.848126-2-alexander.mikhalitsyn@virtuozzo.com>
Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> wrote:
> At the moment, status_xlate_print function prints statusmask as comma-separated
> sequence of enabled statusmask flags. But if we have inverted conntrack ctstatus
> condition then we have to use more complex expression (if more than one flag enabled)
> because nft not supports syntax like "ct status != expected,assured".
>
> Examples:
> ! --ctstatus CONFIRMED,ASSURED
> should be translated as
> ct status & (assured|confirmed) == 0
>
> ! --ctstatus CONFIRMED
> can be translated as
> ct status != confirmed
"! --ctstatus CONFIRMED" means 'true if CONFIRMED bit is not set'
But "ct status != confirmed" means 'true if ct status contains any value
except confirmed.
Example: ct->status has confirmed and assured bits set.
Then:
"! --ctstatus CONFIRMED" won't match (the bit is set).
ct status != confirmed returns true (3 != 1)
ct (status & confirmed) == 0 won't match (the bit is set).
next prev parent reply other threads:[~2021-03-31 10:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 10:29 [iptables PATCH v3 1/2] extensions: libxt_conntrack: print xlate state as set Alexander Mikhalitsyn
2021-03-31 10:29 ` [iptables PATCH v3 2/2] extensions: libxt_conntrack: print xlate status " Alexander Mikhalitsyn
2021-03-31 10:58 ` Florian Westphal [this message]
2021-03-31 13:05 ` Alexander Mikhalitsyn
2021-03-31 11:01 ` [iptables PATCH v3 1/2] extensions: libxt_conntrack: print xlate state " Florian Westphal
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