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

Zhang, Qi Z qi.z.zhang at intel.com
Sat Jan 9 02:01:22 CET 2021



> -----Original Message-----
> From: Thomas Monjalon <thomas at monjalon.net>
> Sent: Friday, January 8, 2021 6:36 PM
> To: Yigit, Ferruh <ferruh.yigit at intel.com>; Zhang, Qi Z <qi.z.zhang at intel.com>;
> Guo, Jia <jia.guo at intel.com>; Andrew Rybchenko
> <andrew.rybchenko at oktetlabs.ru>
> Cc: Wu, Jingjing <jingjing.wu at intel.com>; Yang, Qiming
> <qiming.yang at intel.com>; Wang, Haiyue <haiyue.wang at intel.com>;
> dev at dpdk.org; orika at nvidia.com; getelson at nvidia.com
> 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 at monjalon.net>
> > >>> 07/01/2021 16:24, Zhang, Qi Z:
> > >>>> From: Thomas Monjalon <thomas at monjalon.net>
> > >>>>> 07/01/2021 13:47, Zhang, Qi Z:
> > >>>>>> From: Thomas Monjalon <thomas at monjalon.net>
> > >>>>>>> 07/01/2021 10:32, Guo, Jia:
> > >>>>>>>> From: Thomas Monjalon <thomas at 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://tools.ietf.org/html/rfc7348).
> > >>>>
> > >>>> "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.

> 
> 
> > > 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.
> 



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