Subject: Re: [PATCH v6] Netfilter ring buffer support

From: Pablo Neira Ayuso <[email-masked]>
Date: Thu, 8 Mar 2012 02:28:49 +0100

On Tue, Mar 06, 2012 at 12:19:42AM +0100, Richard Weinberger wrote:
> This patch set merges ipt_LOG and ip6t_LOG and adds ring buffer support
> to xt_LOG.
> 
> Using "--ring" an user can create LOG rules which log messages into
> one or more ring buffers.
> Each ring buffer is represented as pipe-like file in
> /proc/net/netfilter/nf_log_ring/.

I've spent part of the evening testing this and checking its
possibilities, the drawbacks that I see for this contribution are:

* it uses the /proc entry, we have rejected similar add-ons in the
  past that have used these interfaces.
* one single reader can be reading at a time.

Having said that, I still think that the feature that this provides
is useful, but I think that implementing this in user-space over
nfnetlink_log results in a much more flexible solution.

I have made proof-of-concept daemon (it's a quick hack of several
hours) that implements the similar feature over nfnetlink_log,
advantages are:

* You don't need to upgrade your kernel / iptables.
* You only need to install libnfnetlink, libnetfilter_log and the
  daemon.
* It can be extended to support multiple readers.

So my conclusion is that you can make this in userspace in a much more
flexible way.

You can find it here:

http://1984.lsi.us.es/git/rlogd/

The initial commit provides some description on how to use it:

http://1984.lsi.us.es/git/rlogd/commit/?id=ccb88a8dc8ad674b860f2d3edabf07fe4830baf3

I don't plan to develop / maintain that software. The last thing I
want in my todo list is yet another thing to maintain. If someone is
interested, please, feel free to grab it, make a nice website for it
and maintain it.

The repository also contains an unfinished patch to add LOG format
support to libnetfilter_log.