From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Benc Subject: Re: [PATCH net 0/2] lwtunnel: make it really work, for IPv4 Date: Wed, 23 Sep 2015 16:29:27 +0200 Message-ID: <20150923162927.6d437a1f@griffin> References: <87zj0d92ba.fsf@x220.int.ebiederm.org> <20150923080957.GB29680@pox.localdomain> <87lhbx72j2.fsf@x220.int.ebiederm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Thomas Graf , netdev@vger.kernel.org, Roopa Prabhu To: ebiederm@xmission.com (Eric W. Biederman) Return-path: Received: from mx1.redhat.com ([209.132.183.28]:57850 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754633AbbIWO3c (ORCPT ); Wed, 23 Sep 2015 10:29:32 -0400 In-Reply-To: <87lhbx72j2.fsf@x220.int.ebiederm.org> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 23 Sep 2015 07:17:53 -0500, Eric W. Biederman wrote: > Assuming the transport is UDP then it would be a UDP socket. That > socket will have all of the information needed to construct the outer > header as the receive path of that socket removes the outer header. > > I admit you can't use the cached dst. It is the wrong on that socket. > > My point is that if we have the UDP socket and we have the sk we have > all of the information we need to compute the reverse dst. That (single) UDP socket may represent many tunnels with different parameters. Knowing the socket is still not enough to construct the data. The only place where the needed data is stored is routing table which won't help us much for ARP, and the metadata dst attached to the incoming skb. Jiri -- Jiri Benc