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Date: Wed, 07 Aug 2013 17:07:47 -0700
From: Ben Greear <greearb@...delatech.com>
To: "Vitaly E. Lavrov" <lve@...p.ru>
CC: netdev@...r.kernel.org, davem@...emloft.net,
Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH] veth: remove hardware checksum feature
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 <greearb@...delatech.com>
Candela Technologies Inc http://www.candelatech.com
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