From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 5/5] ipv4: Add FIB nexthop exceptions. Date: Tue, 17 Jul 2012 07:25:34 -0700 (PDT) Message-ID: <20120717.072534.1265804777758072167.davem@davemloft.net> References: <20120717.061435.1733209287175819043.davem@davemloft.net> <1342533605.2626.680.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: eric.dumazet@gmail.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:50385 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753761Ab2GQOZh (ORCPT ); Tue, 17 Jul 2012 10:25:37 -0400 In-Reply-To: <1342533605.2626.680.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Tue, 17 Jul 2012 16:00:05 +0200 > On Tue, 2012-07-17 at 06:14 -0700, David Miller wrote: >> In a regime where we have subnetted route entries, we need a way to >> store persistent storage about destination specific learned values >> such as redirects and PMTU values. >> >> This is implemented here via nexthop exceptions. >> >> The initial implementation is a simple linked list, and can be >> expanded to a hash table when it is shown to be justified. > > Say a typical host uses a single default route, I am trying to convince > myself it can really use a simple linked list ? > > Arent PMTU entries added by messages coming from untrusted sources ? They are trusted when we validate them at the socket layer, at least as is done for TCP. I totally agree that we'll need to adjust the list into something more sophisticated, but that's an implementation detail rather than something that requires the actual infrastructure to be redone.