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

From: "Samudrala, Sridhar" <[email-masked]>
Date: Fri, 04 Mar 2016 13:27:08 -0800

On 3/4/2016 12:41 PM, John Fastabend wrote:
> 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.

No. This will not break specifying only src or dst port. The value/mask for the
unspecified port will be set to zero. So it should be fine.

For ex:
	match tcp src 1024 ffff match tcp dst 80 ffff
		=> match 04000050/ffffffff at nexthdr+0
	match tcp src 1024 ffff
		=> match 04000000/ffff0000 at nexthdr+0
	match tcp dst 80 ffff
		=> match 00000050/0000ffff at nexthdr+0

>   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