From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Abeni Subject: Re: [PATCH net-next 1/3] ipv6: fix route cache dump Date: Tue, 17 Oct 2017 21:35:17 +0200 Message-ID: <1508268917.2548.6.camel@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Martin KaFai Lau , Linux Kernel Network Developers , "David S. Miller" , Hannes Frederic Sowa To: Eric Dumazet , Wei Wang Return-path: Received: from mx1.redhat.com ([209.132.183.28]:57111 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965952AbdJQTfU (ORCPT ); Tue, 17 Oct 2017 15:35:20 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Hi, On Tue, 2017-10-17 at 11:41 -0700, Eric Dumazet wrote: > On Tue, Oct 17, 2017 at 11:26 AM, Wei Wang wrote: > > On Tue, Oct 17, 2017 at 10:40 AM, Paolo Abeni wrote: > > > After the commit 2b760fcf5cfb ("ipv6: hook up exception table to > > > store dst cache"), entries in the routing cache are not shown by: > > > > > > ip route show cache > > > > Hi Paolo, > > > > Thanks for doing this. > > But I think your patch does not take care of the case where there are > > a lot of cached routes in the exception table and 1 skb is just not > > enough to dump the main route + all cached routes in the exception > > table. > > In this case, your patch will keep dumping the same main route. > > > > I think some logic needs to be incorporated into the fib6_walk() so > > that it can also remember the last dumped cached route if necessary in > > the exception table and start from there for the next dump. > > I do have a patch for that and that patch tries to keep a linked list > > of all cached routes from the exception table in the walker struct and > > remove any routes that are already dumped. > > It is a bit complicated and might not be the best solution. And as > > IPv4 already does not support dumping cached routes, I did not send > > that out in the previous patch series. Thanks for the feedback. You are right, I was too hasty with this. > Yes, since we no longer dump IPV4 cached routes, I doubt anyone > depends on IPv6 cached routes, but not on IPv4 ones. > > Paolo, do you have a concrete use case for this ? I have a testing script looking for that, but I guess I can adapt it. I'm fine with dropping cached routes dumping support if there is agreement on that. I haven't understood that such change was intentional. Cheers, Paolo