Re: [dpdk-dev] [dpdk-dev v2 1/2] ethdev: add new tunnel type for ecpri

[Ori Kam <orika@nvidia.com>]

Hi,

> -----Original Message-----
> From: Zhang, Qi Z <qi.z.zhang@intel.com>
> Sent: Saturday, January 9, 2021 3:01 AM
> Subject: RE: [dpdk-dev] [dpdk-dev v2 1/2] ethdev: add new tunnel type for ecpri
> 
> 
> 
> > -----Original Message-----
> > From: Thomas Monjalon <thomas@monjalon.net>
> > Subject: Re: [dpdk-dev] [dpdk-dev v2 1/2] ethdev: add new tunnel type for
> ecpri
> >
> > 08/01/2021 10:29, Andrew Rybchenko:
> > > On 1/8/21 11:57 AM, Ferruh Yigit wrote:
> > > > On 1/8/2021 1:41 AM, Zhang, Qi Z wrote:
> > > >> From: Thomas Monjalon <thomas@monjalon.net>
> > > >>> 07/01/2021 16:24, Zhang, Qi Z:
> > > >>>> From: Thomas Monjalon <thomas@monjalon.net>
> > > >>>>> 07/01/2021 13:47, Zhang, Qi Z:
> > > >>>>>> From: Thomas Monjalon <thomas@monjalon.net>
> > > >>>>>>> 07/01/2021 10:32, Guo, Jia:
> > > >>>>>>>> From: Thomas Monjalon <thomas@monjalon.net>
> > > >>>>>>>>> 24/12/2020 07:59, Jeff Guo:
> > > >>>>>>>>>> --- a/lib/librte_ethdev/rte_ethdev.h
> > > >>>>>>>>>> +++ b/lib/librte_ethdev/rte_ethdev.h
> > > >>>>>>>>>> @@ -1219,6 +1219,7 @@ enum rte_eth_tunnel_type {
> > > >>>>>>>>>>       RTE_TUNNEL_TYPE_IP_IN_GRE,
> > > >>>>>>>>>>       RTE_L2_TUNNEL_TYPE_E_TAG,
> > > >>>>>>>>>>       RTE_TUNNEL_TYPE_VXLAN_GPE,
> > > >>>>>>>>>> +    RTE_TUNNEL_TYPE_ECPRI,
> > > >>>>>>>>>>       RTE_TUNNEL_TYPE_MAX,
> > > >>>>>>>>>>   };
> > > >>>>>>>>>
> > > >>>>>>>>> We tried to remove all these legacy API in DPDK 20.11.
> > > >>>>>>>>> Andrew decided to not remove this one because it is not yet
> > > >>>>>>>>> completely replaced by rte_flow in all drivers.
> > > >>>>>>>>> However, I am against continuing to update this API.
> > > >>>>>>>>> The opposite work should be done: migrate to rte_flow.
> > > >>>>>>>>
> > > >>>>>>>> Agree but seems that the legacy api and driver legacy
> > > >>>>>>>> implementation still keep in this release, and there is no a
> > > >>>>>>>> general way to replace the legacy by rte_flow right now.
> > > >>>>>>>
> > > >>>>>>> I think rte_flow is a complete replacement with more features.
> > > >>>>>>
> > > >>>>>> Thomas, I may not agree with this.
> > > >>>>>>
> > > >>>>>> Actually the "enum rte_eth_tunnel_type" is used by
> > > >>>>>> rte_eth_dev_udp_tunnel_port_add A packet with specific dst udp
> > > >>>>>> port will be recognized as a specific tunnel packet type (e.g.
> > > >>>>>> vxlan, vxlan-gpe,
> > > >>>>> ecpri...) In Intel NIC, the API actually changes the
> > > >>>>> configuration of the packet parser in HW but not add a filter
> > > >>>>> rule and I guess all other devices may enable it in a similar way.
> > > >>>>>> so naturally it should be a device (port) level configuration
> > > >>>>>> but not a rte_flow
> > > >>>>> rule for match, encap, decap...
> > > >>>>>
> > > >>>>> I don't understand how it helps to identify an UDP port if there
> > > >>>>> is no rule for this tunnel.
> > > >>>>> What is the usage?
> > > >>>>
> > > >>>> Yes, in general It is a rule, it matches a udp packet's dst port
> > > >>>> and the action is
> > > >>> "now the packet is identified as vxlan packet" then all other
> > > >>> rte_flow rules that match for a vlxan as pattern will take effect.
> > > >>> but somehow, I think they are not rules in the same domain, just
> > > >>> like we have dedicate API for mac/vlan filter, we'd better have a
> > > >>> dedicate API for this also. ( RFC for Vxlan explains why we need
> > > >>> this.
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftools.ietf
> .org%2Fhtml%2Frfc7348&amp;data=04%7C01%7Corika%40nvidia.com%7C46b2
> d8f48944422f0d9008d8b43a2293%7C43083d15727340c1b7db39efd9ccc17a%7
> C0%7C0%7C637457509081543237%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC
> 4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&a
> mp;sdata=RYWFMjuxkcUZ982kK2s44tBAjf%2FTkDyaa7VEybCtxOo%3D&amp;res
> erved=0).
> > > >>>>
> > > >>>> "Destination Port: IANA has assigned the value 4789 for the VXLAN
> > > >>>> UDP port, and this value SHOULD be used by default as the
> > > >>>> destination UDP port.  Some early implementations of VXLAN have
> > > >>>> used other values for the destination port.  To enable
> > > >>>> interoperability with these implementations, the destination port
> > SHOULD be configurable."
> > > >>>
> > > >>> Yes the port number is free.
> > > >>> But isn't it more natural to specify this port number as part of
> > > >>> the rte_flow rule?
> > > >>
> > > >> I think if we have a rte_flow action type that can be used to set a
> > > >> packet's tunnel type xxx, like below #flow create eth/ipv4/udp port
> > > >> is 4789/... action set_tunnel_type VxLAN / end then we may replace
> > > >> it with rte_flow, but I'm not sure if it's necessary, please share
> > > >> if you have a better idea.
> >
> > Of course we can specify the UDP port in rte_flow rule.
> > Please check rte_flow_item_udp.
> > That's a basic of rte_flow.
> 
> Its not about the pattern match, it's about the action, what we need is a
> rte_flow action to "define a packet's tunnel type", but we don't have.
> 
> #flow create eth/ipv4/udp port is 4789/... action set_tunnel_type VxLAN
> 
> I think rte_eth_dev_udp_tunnel_port_add does this job well already, if we plan
> to move it to rte_flow, at least we need a replacement solution.
> 

Let me see if I understand it correctly.
In your case, the issue is that you need to configure the HW to parse the packet correctly right?
It is not about the matching it is about the configuration of the HW, you wish to tell
the HW that the packet should be parsed by different means correct?

If this is the case it sounds to me that you should use rte_flow and if the 
user adds the following rule:
#flow create pattern eth / ivp4 / udp port is 4789 / .. action .....
You simply need to configure your HW to support the ecpri configuration.


> >
> >
> > > > Isn't this more a device configuration than filtering, not sure
> > > > about using rte_flow for this.
> > >
> > > +1
> >
> > A device configuration? No, setting an UDP port is a stack configuration.
> >
> >
> > > >> BTW, are we going to move all other filter like mac , VLAN
> > > >> filter/strip/insert into rte_flow finally?
> >
> > Yes I think it should be the direction.
> > All of this can be achieved with rte_flow.
> >
> >
> > > >> if that's the plan, though I don't have much inputs for this right
> > > >> now, but I think we may not need to prevent new features be added
> > > >> based on current API if it does not introduce more complexity and
> > > >> not break anything.
> >
> > If we continue updating old API, we are just forking ourself:
> > having 2 APIs for the same feature is a non-sense.
> > We must remove APIs which are superseded by rte_flow.
> >