Hi Richard, On Thu, Mar 08, 2012 at 10:02:45AM +0100, Richard Weinberger wrote: > On 08.03.2012 02:28, Pablo Neira Ayuso wrote: > >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. > > My fist implementation used sysfs/debug. > I've switched to /proc/net/netfilter/ to make it consistent to the other > netfilter stuff... > > Moving back to sysfs/debug/whatever can be done within minutes. > > >* one single reader can be reading at a time. > > In which use-cache you need two _consuming_ readers? One scenario in which two sysadmins are checking the logs to debug some issues seems reasonable to me. Anyway, my main points after testing several your buffer-ring things are at the bottom of this email. > Steve's ring_buffer supports also concurrent non-consuming reads. > I can add support for this... > > >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. > > I really don't like this rlogd thing. > > 1. It's yet another random netfilter userspace component. > Please don't fragment it more. IMO modularity is a good thing, independent user-space components allow you to just upgrade the thing that you require. > Installing iptables/conntrack/ulogd/etc... is already enough PITA > because not all distros ship all this clustered components. I think that recompiling your kernel or even wait until your distro ships the new kernel with new extensions will take longer than packaging some small user-space software and deploying it. Not talking about packaging a new iptables package containing support for some new feature. This rlogd proof-of-concept thing (and user-space stuff in general) will: 1) not need any kernel update. 2) be very easy to make a package and to deploy. 3) require no Linux kernel update since NFLOG has been there since long time. > 2. As I described in my very fist RLOG patch, NFLOG does not include > the same information. > You cannot derive "PHYSIN" and "PHYSOUT" from the packet header. Looking at the code, those are included if bridging is enabled. Otherwise, I'll be happy to take a patch for this. > 3. rlogd needs NFLOG which copies every packet (header) to userspace. > What about performance...? Reliability is also important, running things in user-space means that bugs will no crash your system. Instead, they may crash your logging daemon. What I find hard to justify is that this feature can be implemented in user-space with the existing netfilter logging interface. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
