Subject: Re: [net-next PATCH 7/7] net: ixgbe: add support for tc_u32 offload

From: "Amir Vadai\"" <[email-masked]>
Date: Thu, 4 Feb 2016 09:30:50 +0200

On Wed, Feb 03, 2016 at 01:29:59AM -0800, John Fastabend wrote:
> This adds initial support for offloading the u32 tc classifier. This
> initial implementation only implements a few base matches and actions
> to illustrate the use of the infrastructure patches.
> 
> However it is an interesting subset because it handles the u32 next
> hdr logic to correctly map tcp packets from ip headers using the ihl
> and protocol fields. After this is accepted we can extend the match
> and action fields easily by updating the model header file.
> 
> Also only the drop action is supported initially.
> 
> Here is a short test script,
> 
>  #tc qdisc add dev eth4 ingress
>  #tc filter add dev eth4 parent ffff: protocol ip \
> 	u32 ht 800: order 1 \
> 	match ip dst 15.0.0.1/32 match ip src 15.0.0.2/32 action drop
> 
> <-- hardware has dst/src ip match rule installed -->
> 
>  #tc filter del dev eth4 parent ffff: prio 49152
>  #tc filter add dev eth4 parent ffff: protocol ip prio 99 \
> 	handle 1: u32 divisor 1
>  #tc filter add dev eth4 protocol ip parent ffff: prio 99 \
> 	u32 ht 800: order 1 link 1: \
> 	offset at 0 mask 0f00 shift 6 plus 0 eat match ip protocol 6 ff
>  #tc filter add dev eth4 parent ffff: protocol ip \
> 	u32 ht 1: order 3 match tcp src 23 ffff action drop
> 
> <-- hardware has tcp src port rule installed -->
> 
>  #tc qdisc del dev eth4 parent ffff:
> 
> <-- hardware cleaned up -->
> 
> Signed-off-by: John Fastabend <[email-masked]>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe.h         |    3 
>  drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c |    6 -
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c    |  196 ++++++++++++++++++++++
>  3 files changed, 198 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> index 4b9156c..09c2d9b 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h

[...]

> @@ -8277,6 +8465,7 @@ static int ixgbe_set_features(struct net_device *netdev,
>  	 */
>  	switch (features & NETIF_F_NTUPLE) {
>  	case NETIF_F_NTUPLE:
> +	case NETIF_F_HW_TC:
>  		/* turn off ATR, enable perfect filters and reset */
>  		if (!(adapter->flags & IXGBE_FLAG_FDIR_PERFECT_CAPABLE))
>  			need_reset = true;

I think you have a bug here. I don't see how the NETIF_F_HW_TC case will
happen after masking 'features' out.