Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755334AbXKYPls (ORCPT ); Sun, 25 Nov 2007 10:41:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753188AbXKYPll (ORCPT ); Sun, 25 Nov 2007 10:41:41 -0500 Received: from mail1.webmaster.com ([216.152.64.169]:1145 "EHLO mail1.webmaster.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753178AbXKYPlk (ORCPT ); Sun, 25 Nov 2007 10:41:40 -0500 From: "David Schwartz" To: "Linux-Kernel@Vger. Kernel. Org" Cc: Subject: RE: [RFC/PATCH] SO_NO_CHECK for IPv6 Date: Sun, 25 Nov 2007 07:41:52 -0800 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.6604 (9.0.2911.0) Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 In-Reply-To: X-Authenticated-Sender: joelkatz@webmaster.com X-Spam-Processed: mail1.webmaster.com, Sun, 25 Nov 2007 07:42:41 -0800 (not processed: message from trusted or authenticated source) X-MDRemoteIP: 206.171.168.138 X-Return-Path: davids@webmaster.com Reply-To: davids@webmaster.com X-MDAV-Processed: mail1.webmaster.com, Sun, 25 Nov 2007 07:42:42 -0800 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1398 Lines: 37 > David Schwartz wrote: > >> Regardless of whatever verifications your application is doing > >> on the data, it is not checksumming the ports and that's what > >> the pseudo-header is helping with. > > So what? We are in the case where the data has already gotten > > to him. If it > > got to him in error, he'll reject it anyway. The receive > > checksum check will > > only reject packets that he would reject anyway. That makes it needless. > What if it goes to the wrong recipient who doesn't have the upper- > level checksums? Since that's not him, he has no control over its policy and thus no ability to harm it or help it. > This is the whole point, IPv6 unlike IPv4 does not have IP header > checksums so the high-level needs to protect it by checksumming > the pseudo-header. Exactly. But *he* doesn't need to check that checksum, given that he already got the packet, since he has an upper-level checksum. He is not saying that his reasoning applies to everyone, just that it applies to him. He is not talking about disabling the send checksum, but the receive checksum. He knows that he does not need it. DS - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/