From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH net-next] ipv4: tcp: dont cache unconfirmed intput dst Date: Thu, 28 Jun 2012 07:08:22 +0200 Message-ID: <1340860102.26242.203.camel@edumazet-glaptop> References: <20120627.153454.30398632011109264.davem@davemloft.net> <20120627.164418.1928194990434756968.davem@davemloft.net> <20120627.170101.99084491660488389.davem@davemloft.net> <20120627.170830.811332455348620174.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, hans.schillstrom@ericsson.com To: David Miller Return-path: Received: from mail-wg0-f44.google.com ([74.125.82.44]:45393 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751123Ab2F1FI1 (ORCPT ); Thu, 28 Jun 2012 01:08:27 -0400 Received: by wgbdr13 with SMTP id dr13so1810103wgb.1 for ; Wed, 27 Jun 2012 22:08:26 -0700 (PDT) In-Reply-To: <20120627.170830.811332455348620174.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 2012-06-27 at 17:08 -0700, David Miller wrote: > From: David Miller > Date: Wed, 27 Jun 2012 17:01:01 -0700 (PDT) > > > There are quite a number of unwanted side effects from this change, so > > I think we'll have to revert unless you can fix up all of the relevant > > cases quickly. > > Actually I've decided to revert it now. > > Whilst this was a swell idea, there is no way for you to know if > we should really create a cached route or not. > > Even if you could, there is a lot of logic you'll need to code up > so that, f.e., once we determine that we've got a DST_NOCACHE route > when we move to established state, we can insert it into the routing > cache and not mark it DST_NOCACHE any longer. > > But even if we did that, we're going to eat 2 uncached route lookups > for every new incoming legitimate connection. The initial idea was to perform this only for SYN packets received on a listener in SYNCOOKIE mode. I'll resend the patch when fully implemented, instead of a forward patch. Thanks