From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Klassert Subject: Re: Looking for a lost patch Date: Thu, 28 May 2015 07:51:52 +0200 Message-ID: <20150528055150.GG27342@secunet.com> References: <20150520063223.GM8928@secunet.com> <20150521.172524.1057695410816294973.davem@davemloft.net> <20150527083514.GB27342@secunet.com> <20150527.114603.897841724165037352.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: , , To: David Miller Return-path: Received: from a.mx.secunet.com ([195.81.216.161]:49119 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751394AbbE1FwA (ORCPT ); Thu, 28 May 2015 01:52:00 -0400 Content-Disposition: inline In-Reply-To: <20150527.114603.897841724165037352.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, May 27, 2015 at 11:46:03AM -0400, David Miller wrote: > From: Steffen Klassert > Date: Wed, 27 May 2015 10:35:16 +0200 > > > We currently check if a socket is attached to a skb and do socket > > error notification in this case, otherwise we do PMTU discovery if > > the packet is too big. Looks like this socket check is not sufficient > > if the packet is already transmitted through a tunnel device. > > > > I wonder if we have something to know that a packet was already > > transmitted through a tunnel device. We could switch from socket > > notification to PMTU discovery in this case. > > Generally speaking, we should not be orphaning the socket as it > traverses through tunnels. > > In fact we have taken great pains to avoid doing this. Yes, I'm aware of this. I don't want to orphan the socket, all I wanted to do is to change the way we notify about MTU changes. I.e. use icmpv6_send() instead of xfrm_local_error() if the packet traversed a tunnel, that's why I wondered whether we can know this.