From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baruch Even Subject: Multicast and hardware checksum Date: Fri, 08 Jun 2007 01:33:14 +0300 Message-ID: <466887AA.800@ev-en.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: Netdev Return-path: Received: from rrcs-24-123-59-149.central.biz.rr.com ([24.123.59.149]:52581 "EHLO galon.ev-en.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935470AbXFGWdz (ORCPT ); Thu, 7 Jun 2007 18:33:55 -0400 Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hello, I have a machine on which I have an applications that sends multicast through eth interface with hardware tx checksum enabled. On the same machine I have mrouted running that routes the multicast traffic to a set of ppp interfaces. The packets that are received by the client have their checksum fixed on some number which is incorrect. If I disable tx checksum on the eth device the packets arrive with the proper checksum. I still haven't followed the code paths to see how to fix this, maybe someone knows the relevant code and can find it faster. Baruch