From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: [PATCH] veth: remove hardware checksum feature Date: Wed, 07 Aug 2013 17:07:47 -0700 Message-ID: <5202E153.4060202@candelatech.com> References: <51F15E50.8080208@guap.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, davem@davemloft.net, Eric Dumazet To: "Vitaly E. Lavrov" Return-path: Received: from mail.candelatech.com ([208.74.158.172]:59836 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933213Ab3HHAH6 (ORCPT ); Wed, 7 Aug 2013 20:07:58 -0400 In-Reply-To: <51F15E50.8080208@guap.ru> Sender: netdev-owner@vger.kernel.org List-ID: On 07/25/2013 10:20 AM, Vitaly E. Lavrov wrote: > The network device VETH can't support the feature NETIF_F_HW_CSUM. > All locally generated packets have invalid checksum. > Wrong commit http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8093315a91340bca52549044975d8c7f673b28a1 ( kernel 3.9.0 ) > > Workaround "ethtool -K vethX tx off" > > Possible patch: > > diff --git a/drivers/net/veth.c b/drivers/net/veth.c > index 177f911..3db97da 100644 > --- a/drivers/net/veth.c > +++ b/drivers/net/veth.c > @@ -254,7 +254,7 @@ static const struct net_device_ops veth_netdev_ops = { > }; > > #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_ALL_TSO | \ > - NETIF_F_HW_CSUM | NETIF_F_RXCSUM | NETIF_F_HIGHDMA | \ > + NETIF_F_RXCSUM | NETIF_F_HIGHDMA | \ > NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \ > NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX ) I see the same problem. My test case is a bit complicated, but the gist is that I have a VETH pair, one with IP (veth1), one connected to a bridge-like-thing (veth2). The UDP frames sent on veth1 appear on veth2, and when I sniff veth2, the packets show broken checksum. The work-around mentioned in Vitaly's email above fixes the problem for me (I did not try the patch yet). Eric: You responded originally that you needed more info. If my explanation above is not sufficient, please let me know what you need... Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com