netdev - Re: [PATCH] ehea: Fix a checksum issue on the receive path

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Date:	Fri, 08 Oct 2010 06:45:30 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	leitao@...ux.vnet.ibm.com
Cc:	davem@...emloft.net, netdev@...r.kernel.org,
	Jay Vosburgh <fubar@...ibm.com>
Subject: Re: [PATCH] ehea: Fix a checksum issue on the receive path

Le jeudi 07 octobre 2010 à 19:17 -0400, leitao@...ux.vnet.ibm.com a
écrit :
> Currently we set all skbs with CHECKSUM_UNNECESSARY, even
> those whose protocol we don't know. This patch just
> add the CHECKSUM_COMPLETE tag for non TCP/UDP packets.
> 
> Reported-by: Eric Dumazet <eric.dumazet@...il.com>
> Signed-off-by: Breno Leitao <leitao@...ux.vnet.ibm.com>
> Signed-off-by: Jay Vosburgh <fubar@...ibm.com>
> ---
>  drivers/net/ehea/ehea_main.c |    9 ++++++++-
>  drivers/net/ehea/ehea_qmr.h  |    1 +
>  2 files changed, 9 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
> index 0471cae..45fd045 100644
> --- a/drivers/net/ehea/ehea_main.c
> +++ b/drivers/net/ehea/ehea_main.c
> @@ -533,8 +533,15 @@ static inline void ehea_fill_skb(struct net_device *dev,
>  	int length = cqe->num_bytes_transfered - 4;	/*remove CRC */
>  
>  	skb_put(skb, length);
> -	skb->ip_summed = CHECKSUM_UNNECESSARY;
>  	skb->protocol = eth_type_trans(skb, dev);
> +
> +	/* The packet was not an IPV4 packet so a complemented checksum was
> +	   calculated. The value is found in the Internet Checksum field. */
> +	if (cqe->status & EHEA_CQE_BLIND_CKSUM) {
> +		skb->ip_summed = CHECKSUM_COMPLETE;
> +		skb->csum = csum_unfold(~cqe->inet_checksum_value);
> +	} else
> +		skb->ip_summed = CHECKSUM_UNNECESSARY;
>  }
>  

Hi Breno

Just to be clear : packets with wrong checksums are not given to upper
stack, so a tcpdump can not display them ? I am not sure many drivers do
that.

(EHEA_CQE_STAT_ERR_TCP, EHEA_CQE_STAT_ERR_IP)

Thanks !


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