From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: IPsec PMTUD problem Date: Thu, 05 Apr 2007 14:09:20 +0200 Message-ID: <4614E6F0.10905@trash.net> References: <46110ED1.9070209@trash.net> <20070403095510.GA7754@gondor.apana.org.au> <46128187.4090601@trash.net> <20070405120425.GC10972@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: Linux Netdev List To: Herbert Xu Return-path: Received: from stinky.trash.net ([213.144.137.162]:49679 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992511AbXDEMJ0 (ORCPT ); Thu, 5 Apr 2007 08:09:26 -0400 In-Reply-To: <20070405120425.GC10972@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Herbert Xu wrote: > On Tue, Apr 03, 2007 at 06:32:07PM +0200, Patrick McHardy wrote: > >>I'm not sure I understand how this would work, the ICMP message >>looks the same in both cases. Or are you suggesting to >>differentiate based on the source of the ICMP message? > > > Actually you're right, this can't work in the general case. Even > if we had real devices for IPsec tunnels, there is still no way to > reliably figure out which device we should attribute a given MTU > event to if the same address appears on more than one device. > > >>Yes, that would work as a workaround, but it still seems like >>something worth fixing. > > > One possible solution is to not send MTU errors to ourselves since > we it wouldn't give us any new information. We'd need to audit the > users of icmp_send to make sure that there isn't a legitimate case > where we'd want to do that. One such case is delivery of errors to sockets. We'd need to make sure the errors are delivered some other way.