From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Chapman Subject: Re: [PATCH 3/3] [PPP] L2TP: Fix skb handling in pppol2tp_xmit Date: Tue, 18 Sep 2007 21:19:33 +0100 Message-ID: <46F032D5.7020806@katalix.com> References: <20070918120438.GA9121@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , Michal Ostrowski , Paul Mackerras , =?ISO-8859-1?Q?Toralf_F=F6rster?= , netdev@vger.kernel.org To: Herbert Xu Return-path: Received: from s36.avahost.net ([74.53.95.194]:51266 "EHLO s36.avahost.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751755AbXIRUTs (ORCPT ); Tue, 18 Sep 2007 16:19:48 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Herbert Xu wrote: > [PPP] L2TP: Fix skb handling in pppol2tp_xmit > > This patch makes pppol2tp_xmit call skb_cow_head so that we don't modify > cloned skb data. It also gets rid of skb2 we only need to preserve the > original skb for congestion notification, which is only applicable for > ppp_async and ppp_sync. > > The other semantic change made here is the removal of socket accounting > for data tranmitted out of pppol2tp_xmit. The original code leaked any > existing socket skb accounting. We could fix this by dropping the > original skb owner. However, this is undesirable as the packet has not > physically left the host yet. > > In fact, all other tunnels in the kernel do not account skb's passing > through to their own socket. In partciular, ESP over UDP does not do > so and it is the closest tunnel type to PPPoL2TP. So this patch simply > removes the socket accounting in pppol2tp_xmit. The accounting still > applies to control packets of course. > > I've also added a reminder that the outgoing checksum here doesn't work. > I suppose existing deployments don't actually enable checksums. > > Signed-off-by: Herbert Xu This one causes my test system to lock up. I'll investigate. Please don't apply this patch for now. -- James Chapman Katalix Systems Ltd http://www.katalix.com Catalysts for your Embedded Linux software development