From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowmini Varadhan Subject: Re: Q: bad routing table cache entries Date: Sun, 3 Jan 2016 20:05:39 -0500 Message-ID: <20160104010539.GC9087@oracle.com> References: <5682665A.7090102@list.ru> <20151229152208.GA22423@oracle.com> <5683D131.4090703@list.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev To: Stas Sergeev Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:23933 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751974AbcADBFu (ORCPT ); Sun, 3 Jan 2016 20:05:50 -0500 Content-Disposition: inline In-Reply-To: <5683D131.4090703@list.ru> Sender: netdev-owner@vger.kernel.org List-ID: On (12/30/15 15:42), Stas Sergeev wrote: > 29.12.2015 18:22, Sowmini Varadhan =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > > Do you have admin control over the ubuntu router? > > If yes, you might want to check the shared_media [#] setting=20 > > on that router for the interfaces with overlapping subnets. > > (it is on by default, I would try turning it off). > That didn't help, problem re-appears. the code that sets things up for redirect is this: if (out_dev =3D=3D in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && skb->protocol =3D=3D htons(ETH_P_IP) && (IN_DEV_SHARED_MEDIA(out_dev) || inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) IPCB(skb)->flags |=3D IPSKB_DOREDIRECT; If you are still seeing the problematic redirect after disabling shared_media, then you would need to trace through inet_addr_onlink() to see why it was not returning false. As I said before, afaict from reading the code, inet_addr_onlink looks right. So there may be somethi= ng unusual with your netmask config on in_dev/out_dev. But even if the redirect is suppressed, sounds like the network/netmask config is sub-optimal, since each packet gets (needlessly?) sent up/down the router's in_dev/out_dev. That should be avoided, if possibl= e. --Sowmini