[dpdk-stable] [dpdk-dev] net/i40e: fix vlan packets drop

[Kevin Traynor]

On 14/10/2019 08:53, Xiao Zhang wrote:
> vlan packets with ip length bigger then 1496 will not be received by
> i40e due to wrong packets size checking. This patch fixes the issue by
> correcting the maximum frame size during checking.
> 
> Fixes: 35b2d13fd6fd ("net: add rte prefix to ether defines")

To make sure it is backported to the correct stable branches, please tag
the commit that introduced the bug, not the last commit to touch the line.

> Cc: stable at dpdk.org
> 
> Signed-off-by: Xiao Zhang <xiao.zhang at intel.com>
> ---
>  drivers/net/i40e/i40e_ethdev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
> index 2ca14da..156d67b 100644
> --- a/drivers/net/i40e/i40e_ethdev.c
> +++ b/drivers/net/i40e/i40e_ethdev.c

What about vf?

> @@ -12103,7 +12103,7 @@ i40e_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
>  		return -EBUSY;
>  	}
>  
> -	if (frame_size > RTE_ETHER_MAX_LEN)
> +	if (frame_size > RTE_ETHER_MAX_LEN + I40E_VLAN_TAG_SIZE * 2)
>  		dev_data->dev_conf.rxmode.offloads |=
>  			DEV_RX_OFFLOAD_JUMBO_FRAME;
>  	else
> 

+cc Ian, who looked into MTU for i40e a while back.

MTU code changing makes me nervous. You would need to look through
everywhere there is something related to pkt len to check it is still ok.

E.g. if I got it right (maybe I miss something), this means a 1500 mtu
will set frame_size to 1526, which will turn off jumbo and set
dev_data->dev_conf.rxmode.max_rx_pkt_len = 1526

Then in i40e_rx_queue_config()

rxq->max_pkt_len = RTE_MIN(len, data->dev_conf.rxmode.max_rx_pkt_len);
                   ^^^ lets say max_rx_pkt_len (1526) is the min

if (data->dev_conf.rxmode.offloads & DEV_RX_OFFLOAD_JUMBO_FRAME) {

[snip jumbo on branch]

} else {
	if (rxq->max_pkt_len < RTE_ETHER_MIN_LEN ||
		rxq->max_pkt_len > RTE_ETHER_MAX_LEN) {
                ^^^ 1526           ^^^ 1518

		PMD_DRV_LOG(ERR, "maximum packet length must be "
			    "larger than %u and smaller than %u, "
			    "as jumbo frame is disabled",
			    (uint32_t)RTE_ETHER_MIN_LEN,
			    (uint32_t)RTE_ETHER_MAX_LEN);
		return I40E_ERR_CONFIG;
                ^^^ Error returned ???
	}
}