[dpdk-dev] [PATCH v2 2/6] ethdev: add GTPC and GTPU items

[Xing, Beilei]

Hi Adrien,

> -----Original Message-----
> From: Adrien Mazarguil [mailto:adrien.mazarguil at 6wind.com]
> Sent: Tuesday, September 12, 2017 6:47 PM
> To: Xing, Beilei <beilei.xing at intel.com>
> Cc: Wu, Jingjing <jingjing.wu at intel.com>; Chilikin, Andrey
> <andrey.chilikin at intel.com>; dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2 2/6] ethdev: add GTPC and GTPU items
> 
> Hi Beilei,
> 
> On Tue, Sep 12, 2017 at 06:40:50AM +0000, Xing, Beilei wrote:
> > Hi Adrien,
> >
> > > -----Original Message-----
> > > From: Adrien Mazarguil [mailto:adrien.mazarguil at 6wind.com]
> > > Sent: Thursday, September 7, 2017 8:20 PM
> > > To: Xing, Beilei <beilei.xing at intel.com>
> > > Cc: Wu, Jingjing <jingjing.wu at intel.com>; Chilikin, Andrey
> > > <andrey.chilikin at intel.com>; dev at dpdk.org
> > > Subject: Re: [dpdk-dev] [PATCH v2 2/6] ethdev: add GTPC and GTPU
> > > items
> > >
> > > Hi Beilei,
> > >
> > > I assume this patch supersedes [1]?
> > >
> > > [1] http://dpdk.org/ml/archives/dev/2017-August/073501.html
> > >
> > > Thanks for merging testpmd and the API change as a single patch, I
> > > still have a few comments, see below.
> > >
> > > (please add "flow API" somewhere in the title by the way)
> >
> > Thanks for all your comments.
> > Yes, http://dpdk.org/ml/archives/dev/2017-August/073501.html is
> superseded and did merging testpmd and API change.
> > I will update title in next version.
> 
> All right, thanks.
> 
> > > On Thu, Sep 07, 2017 at 07:20:59PM +0800, Beilei Xing wrote:
> > > > This patch adds GTPC and GTPU items to generic rte flow, and also
> > > > exposes the following item fields through the flow command:
> > > >
> > > > - GTPC TEID
> > > > - GTPU TEID
> > > >
> > > > Signed-off-by: Beilei Xing <beilei.xing at intel.com>
> > >
> > > Won't there be a need to match nonspecific GTP traffic as well (both
> > > GTP-C and GTP-U a once), since they use the same structure?
> > >
> > > I'm not familiar with the protocol at all so I wonder if you should
> > > maybe leave the GTP item in addition to those two.
> > >
> >
> > Agree, I will leave the GTP item in next version.
> >
> > GTP-C and GTP-U use the same structure, the difference between them is
> UDP port, 2123 is for GTP-C, and 2152 is for GTP-U.
> > Add GTP-C and GTP -U item since I want to design a user-friendly CLI.
> >
> > For example, if user wants to add such flow: assign GTP-U packets with
> TEID 0x123456 to queue 14.
> > Then use can use following CLI:
> > flow create 0 ingress pattern eth / ipv4 / udp / gtpu teid is 0x123456
> > / end actions queue index 14 / end instead of below CLI to distinguish
> GTP-C and GTP-U with UDP port:
> > flow create 0 ingress pattern eth / ipv4 / udp dst spec 2125 dst mask
> > 0 / gtp teid is 0x123456 / end actions queue index 14 / end
> 
> I agree with you from a usability standpoint it's much nicer. I have one
> question though, could one send GTP-C / GTP-U traffic using nondefault UDP
> ports and expect hardware to match it without explicitly specifying a port in
> the UDP item, that is, is there some property in GTP-C / GTP-U traffic outside
> the UDP port that would theoretically allow a host (even a stateful
> one) to tell them apart?
> 
> If it really depends on the UDP port only, not specifying one will use
> hardware defaults regardless of the item (GTP / GTP-U / GTP-C). However if
> like VXLAN, this default value can be modified outside of rte_flow, most
> users will have to specify it regardless in order to get consistent results
> across various vendors/adapters.

As far as I know, there's no other property in GTP-C / GTP-U traffic outside the UDP port to distinguish GTP-C and GTP-U. And I don't think the value can be modified by user just like VXLAN.

> 
> In any case I don't mind three items. GTP encompasses both GTP-U and
> GTP-C (possibly two different UDP ports at once), while GTP-U and GTP-C
> match exactly one. You only have to describe this properly in the
> documentation.

OK, I will describe it in documentation.

Beilei