Subject: Re: [Intel-wired-lan] [PATCH net-next] net: ixgbe: Fix cls_u32 offload support for ports and fields with masks.

From: John Fastabend <[email-masked]>
Date: Fri, 04 Mar 2016 12:41:53 -0800

On 16-03-04 11:47 AM, Sridhar Samudrala wrote:
> Fix support for 16 bit source/dest port matches in ixgbe model.
> u32 uses a single 32-bit key value for both source and destination ports
> starting at offset 0. So replace the 2 functions with a single function
> that takes this key value/mask to program both source and dest ports.
> 
> Remove the incorrect check for mask in ixgbe_configure_clsu32()
> 
> Tested with the following filters:
> 
>  #tc qdisc add dev p4p1 ingress
>  #tc filter add dev p4p1 parent ffff: protocol ip prio 99 \
> 	handle 800:0:1 u32 ht 800: \
> 	match ip dst 11.0.0.1/24 match ip src 11.0.0.2/24 action drop
> 
>  #tc filter del dev p4p1 parent ffff: protocol ip prio 99 \
> 	handle 800:0:1 u32
>  #tc filter add dev p4p1 parent ffff: protocol ip prio 99 \
> 	handle 1: u32 divisor 1
>  #tc filter add dev p4p1 parent ffff: protocol ip prio 99 \
> 	handle 800:0:10 u32 ht 800: link 1: \
> 	offset at 0 mask 0f00 shift 6 plus 0 eat match ip protocol 6 ff
>  #tc filter add dev p4p1 parent ffff: protocol ip prio 99 \
> 	handle 1:0:10 u32 ht 1: \
> 	match tcp src 1024 ffff match tcp dst 80 ffff action drop
> 
> Signed-off-by: Sridhar Samudrala <[email-masked]>
> ---

But this will break setting only dst port or only src port. Do we
actually need three signatures to match? Something like,

  static struct ixgbe_mat_field ixgbe_tcp_fields[] = {
	{.off = 0, .mask = 0xffffffff, .val = ixgbe_mat_prgm_ports,
  	 .type = IXGBE_ATR_FLOW_TYPE_TCPV4},
	{.off = 0, .mask = 0xffff0000, .val = ixgbe_mat_prgm_dport,
  	 .type = IXGBE_ATR_FLOW_TYPE_TCPV4},
	{.off = 0, .mask = 0x0000ffff, .val = ixgbe_mat_prgm_sport,
  	 .type = IXGBE_ATR_FLOW_TYPE_TCPV4},
  	{ .val = NULL } /* terminal node */
  };

Also just a reminder if we get multiple fields in a ixgbe_mat_field
struct we need to abort out of the for loop in the cls_u32 configure
function. Actually we can probably just push that as its own patch
to make the core function more versatile/usable.

Thanks,
John