netdev - Re: [PATCH 2/6] ibmveth: Implement ethtool hooks to enable/disable checksum offload

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <46B8EF42.1010708@garzik.org>
Date:	Tue, 07 Aug 2007 18:16:34 -0400
From:	Jeff Garzik <jeff@...zik.org>
To:	brking@...ux.vnet.ibm.com
CC:	santil@...ux.vnet.ibm.com, rcjenn@...ux.vnet.ibm.com,
	netdev@...r.kernel.org, linuxppc-dev@...abs.org
Subject: Re: [PATCH 2/6] ibmveth: Implement ethtool hooks to enable/disable
 checksum offload

Brian King wrote:
> Jeff Garzik wrote:
>> Brian King wrote:
>>> This patch adds the appropriate ethtool hooks to allow for enabling/disabling
>>> of hypervisor assisted checksum offload for TCP.
>>>
>>> Signed-off-by: Brian King <brking@...ux.vnet.ibm.com>
>>> ---
>>>
>>>  linux-2.6-bjking1/drivers/net/ibmveth.c |  118 +++++++++++++++++++++++++++++++-
>>>  linux-2.6-bjking1/drivers/net/ibmveth.h |    1 
>>>  2 files changed, 117 insertions(+), 2 deletions(-)
>>>
>>> diff -puN drivers/net/ibmveth.c~ibmveth_csum_offload_ethtool drivers/net/ibmveth.c
>>> --- linux-2.6/drivers/net/ibmveth.c~ibmveth_csum_offload_ethtool	2007-08-01 14:55:14.000000000 -0500
>>> +++ linux-2.6-bjking1/drivers/net/ibmveth.c	2007-08-01 14:55:14.000000000 -0500
>>> @@ -641,12 +641,125 @@ static u32 netdev_get_link(struct net_de
>>>  	return 1;
>>>  }
>>>  
>>> +static void ibmveth_set_rx_csum_flags(struct net_device *dev, u32 data)
>>> +{
>>> +	struct ibmveth_adapter *adapter = dev->priv;
>>> +
>>> +	if (data)
>>> +		adapter->rx_csum = 1;
>>> +	else {
>>> +		adapter->rx_csum = 0;
>>> +		dev->features &= ~NETIF_F_IP_CSUM;
>> why does this RX-related code clear a TX-related flag?
> 
> Its related to how the pSeries firmware works. The firmware provides an interface
> to enable "checksum offload", which means both tx and rx checksum offload from
> the firmware's point of view. The firmware does not support enabling checksum
> offload for only rx. If I disable it for rx I have to disable it for tx as
> well, otherwise the firmware will reject all future tx buffers I throw at it
> that are not checksummed.

ACK once you add a comment describing this :)


-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html