From mboxrd@z Thu Jan 1 00:00:00 1970 From: KOVACS Krisztian Subject: Re: [tproxy,regression] tproxy broken in 2.6.32 Date: Sat, 28 Nov 2009 16:15:15 +0100 Message-ID: <20091128151515.GA20476@sch.bme.hu> References: <1259137434.9191.3.camel@nienna.balabit> <1259310417.3809.5.camel@nienna.balabit> <1259337932.3299.3.camel@bigi> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: KOVACS Krisztian , Andreas Schultz , tproxy@lists.balabit.hu, netdev@vger.kernel.org To: jamal Return-path: Received: from centaur.sch.bme.hu ([152.66.208.5]:49690 "EHLO centaur.sch.bme.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751560AbZK1PiJ (ORCPT ); Sat, 28 Nov 2009 10:38:09 -0500 Content-Disposition: inline In-Reply-To: <1259337932.3299.3.camel@bigi> Sender: netdev-owner@vger.kernel.org List-ID: Hi, On p, nov 27, 2009 at 11:05:32 -0500, jamal wrote: > On Fri, 2009-11-27 at 09:26 +0100, KOVACS Krisztian wrote: > > Hi, > > > > On Thu, 2009-11-26 at 18:19 +0100, Andreas Schultz wrote: > > > Hi, > > > > > > git bisect shows that TPROXY has been broken by commit > > > f7c6fd2465d8e6f4f89c5d1262da10b4a6d499d0, [PATCH] net: Fix RPF to work > > > with policy routing > > > > > > I had a look at the patch, and it seems logical that this would break TPROXY. > > > > Indeed, that's a good catch. If this is indeed the problem you should be > > able to work it around by disabling rpfilter on the ingress interface. > > Does it work that way? > > Not familiar with tproxy, but I suspect the system doesnt see the mark > before policy routing happens. So probably the wrong route cache gets > created. Easy to validate by dumping the route cache. > If thats so, you have to set the mark in pre-route hook if it uses > iptables. It's already on prerouting, so that's not the problem. The problem is that for tproxy to work we've used to have a rule like this: # ip rule add fwmark 1 lookup 100 plus a few iptables rules setting mark values. The issue is that previously fib_validate_source ignored the mark set on the skb, and thus when fib_validate_source() did a FIB lookup, it all went fine, because it found a result of type RTN_UNICAST. However, with your change, and because of the ip rule above not being specific enough now it's returning with type RTN_LOCAL, and that's considered invalid and thus the skb is dropped. The workaround is using more specific ip rules that include the ingress interface name: # ip rule add dev eth0 fwmark 1 lookup 100 (repeat the above for each interface except lo.) Andreas, would you mind giving it a try on your system? -- KOVACS Krisztian