Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932270AbbD1CrR (ORCPT ); Mon, 27 Apr 2015 22:47:17 -0400 Received: from shards.monkeyblade.net ([149.20.54.216]:60423 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932082AbbD1CrP (ORCPT ); Mon, 27 Apr 2015 22:47:15 -0400 Date: Mon, 27 Apr 2015 22:47:13 -0400 (EDT) Message-Id: <20150427.224713.291017556251723132.davem@davemloft.net> To: jaeden.amero@ni.com Cc: nicolas.ferre@atmel.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jeff.westfahl@ni.com, mihai.neagu@ni.com Subject: Re: [PATCH RFC] net/macb: Fix UDPv4 checksum offload From: David Miller In-Reply-To: <1430174610-6834-1-git-send-email-jaeden.amero@ni.com> References: <1430174610-6834-1-git-send-email-jaeden.amero@ni.com> X-Mailer: Mew version 6.6 on Emacs 24.4 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 27 Apr 2015 19:47:14 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 761 Lines: 20 From: Jaeden Amero Date: Mon, 27 Apr 2015 17:43:30 -0500 > If we set the checksum field in the UDP header to 0, the checksum is > computed correctly. I think this is completely bogus. A UDP checksum of zero, means "checksum not computed". And your device isn't computing the checksum at all, but rather is leaving it at zero. You need to handle this properly by computing the checksum in software and then setting the TX descriptor bits such that the chip leaves the checksum field alone. -- 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/