From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: [PATCH 6/10][CTNETLINK] dump counters iif connection ended or counters filled up Date: Mon, 10 Jul 2006 06:47:32 +0200 Message-ID: <44B1DBE4.7010109@trash.net> References: <44ADC3BD.3050609@netfilter.org> <44ADE7BA.4030406@trash.net> <44AE66CA.8030705@netfilter.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: Netfilter Development Mailinglist Return-path: To: Pablo Neira Ayuso In-Reply-To: <44AE66CA.8030705@netfilter.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: netfilter-devel-bounces@lists.netfilter.org Errors-To: netfilter-devel-bounces@lists.netfilter.org List-Id: netfilter-devel.vger.kernel.org Pablo Neira Ayuso wrote: > Patrick McHardy wrote: > >> Pablo Neira Ayuso wrote: >> >>> I think that this patch should also reset counters upon fill up event, >>> comments? >> >> >> Not sure, do you know any users of the counters besides conntrackd? > > > I don't know any ctnetlink user of the counters. Thinking it well this > "counters fill up" issue is tricky. Since netlink is unreliable, what if > the fill up event gets lost? we could reset counters and nobody would > apparently notice. I think that we need an overflow bit in the conntrack > that must be set whenever and overflow happens and unset such bit once > the overflow event has been caught. If a message is lost userspace simply _must_ resync if it wants reliability. If we reset the counter its impossible for userspace to reconstruct the value at which it overflowed, so I don't think we should do that. But you raise a good point, how should userspace react to lost DESTROY messages that contain new information (like counter values)? I don't see how it could reliable handle that case.