netdev - Re: [PATCH v2 2/2] net: dsa: tag_ksz: dont let the hardware process the layer 4 checksum

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Message-ID: <06583db0-ac0e-8e9d-324c-faf3f8b38ac0@gmail.com>
Date:   Wed, 21 Jul 2021 20:55:57 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Lino Sanfilippo <LinoSanfilippo@....de>, woojung.huh@...rochip.com,
        olteanv@...il.com
Cc:     UNGLinuxDriver@...rochip.com, andrew@...n.ch,
        vivien.didelot@...il.com, davem@...emloft.net, kuba@...nel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] net: dsa: tag_ksz: dont let the hardware process
 the layer 4 checksum



On 7/21/2021 2:56 PM, Lino Sanfilippo wrote:
> If the checksum calculation is offloaded to the network device (e.g due to
> NETIF_F_HW_CSUM inherited from the DSA master device), the calculated
> layer 4 checksum is incorrect. This is since the DSA tag which is placed
> after the layer 4 data is considered as being part of the daa and thus
> errorneously included into the checksum calculation.
> To avoid this, always calculate the layer 4 checksum in software.
> 
> Signed-off-by: Lino Sanfilippo <LinoSanfilippo@....de>

Reviewed-by: Florian Fainelli <f.fainelli@...il.com>
-- 
Florian