netdev - Re: [patch net-next v2 0/9] net: sched: introduce chain templates support with offloading to mlxsw

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Date:   Thu, 28 Jun 2018 08:18:47 -0600
From:   David Ahern <dsahern@...il.com>
To:     Jiri Pirko <jiri@...nulli.us>, netdev@...r.kernel.org
Cc:     davem@...emloft.net, jhs@...atatu.com, xiyou.wangcong@...il.com,
        jakub.kicinski@...ronome.com, simon.horman@...ronome.com,
        john.hurley@...ronome.com, mlxsw@...lanox.com,
        sridhar.samudrala@...el.com
Subject: Re: [patch net-next v2 0/9] net: sched: introduce chain templates
 support with offloading to mlxsw

On 6/28/18 7:08 AM, Jiri Pirko wrote:
> Create dummy device with clsact first:
> # ip link add type dummy
> # tc qdisc add dev dummy0 clsact
> 
> There is no template assigned by default:
> # tc chaintemplate show dev dummy0 ingress
> 
> Add a template of type flower allowing to insert rules matching on last
> 2 bytes of destination mac address:
> # tc chaintemplate add dev dummy0 ingress proto ip flower dst_mac 00:00:00:00:00:00/00:00:00:00:FF:FF
> 
> The template is now showed in the list:
> # tc chaintemplate show dev dummy0 ingress
> chaintemplate flower chain 0 
>   dst_mac 00:00:00:00:00:00/00:00:00:00:ff:ff
>   eth_type ipv4
> 
> Add another template, this time for chain number 22:
> # tc chaintemplate add dev dummy0 ingress proto ip chain 22 flower dst_ip 0.0.0.0/16
> # tc chaintemplate show dev dummy0 ingress
> chaintemplate flower chain 0 
>   dst_mac 00:00:00:00:00:00/00:00:00:00:ff:ff
>   eth_type ipv4
> chaintemplate flower chain 22 
>   eth_type ipv4
>   dst_ip 0.0.0.0/16
> 
> Add a filter that fits the template:
> # tc filter add dev dummy0 ingress proto ip flower dst_mac aa:bb:cc:dd:ee:ff/00:00:00:00:00:0F action drop
> 
> Addition of filters that does not fit the template would fail:
> # tc filter add dev dummy0 ingress proto ip flower dst_mac aa:11:22:33:44:55/00:00:00:FF:00:00 action drop
> Error: Mask does not fit the template.
> We have an error talking to the kernel, -1
> # tc filter add dev dummy0 ingress proto ip flower dst_ip 10.0.0.1 action drop
> Error: Mask does not fit the template.
> We have an error talking to the kernel, -1
> 
> Additions of filters to chain 22:
> # tc filter add dev dummy0 ingress proto ip chain 22 flower dst_ip 10.0.0.1/8 action drop
> # tc filter add dev dummy0 ingress proto ip chain 22 flower dst_ip 10.0.0.1 action drop
> Error: Mask does not fit the template.
> We have an error talking to the kernel, -1
> # tc filter add dev dummy0 ingress proto ip chain 22 flower dst_ip 10.0.0.1/24 action drop
> Error: Mask does not fit the template.
> We have an error talking to the kernel, -1
> 
> Removal of a template from non-empty chain would fail:
> # tc chaintemplate del dev dummy0 ingress
> Error: The chain is not empty, unable to delete template.
> We have an error talking to the kernel, -1

Why this restriction? It's a template, so why can't it be removed
regardless of whether there are filters?

> 
> Once the chain is flushed, the template could be removed:
> # tc filter del dev dummy0 ingress
> # tc chaintemplate del dev dummy0 ingress
>