Re: [dpdk-dev] [RFC PATCH 0/3] introduce IF proxy library

[Jerin Jacob <jerinjacobk@gmail.com>]

On Wed, Jan 15, 2020 at 5:58 PM Morten Brørup <mb@smartsharesystems.com> wrote:
>
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Bruce Richardson
> > Sent: Wednesday, January 15, 2020 11:16 AM
> >
> > On Tue, Jan 14, 2020 at 06:38:37PM +0100, Andrzej Ostruszka wrote:
> > > On 1/14/20 4:16 PM, Morten Brørup wrote:
> > > > Andrzej,
> > >
> > > Hello Morten
> > >
> > > > Basically you are adding a very small subset of the Linux IP stack>
> > to interface with DPDK applications via callbacks.
> > >
> > > Yes, at the moment this is limited - we'd prefer first to solicit
> > > some input from community.
> > >
> > > > The library also seems to support interfacing to the route table,
> > > > so it is not "interface proxy" but "IP stack proxy".
> > >
> > > True, to some extent - for example you can bring the interface up and
> > > down which has nothing to do with IP stack.  As for the name of the
> > > library - that is actually part where we are completely open.  The
> > proxy
> > > represents port (thus the name) but that is not all, so any better
> > name
> > > proposals are welcome.
> > >
> > > > You already mention ARP table as future work. How about namespaces,
> > > > ip tables, and other advanced features... I foresee the Devil in
> > the
> > > > details for any real use case.
> > >
> > > Right now I don't know what other things are needed.  This idea is
> > still
> > > early.  However imagine you'd like to use DPDK to speed up packet
> > > processing of IP stack - would you like to implement all the
> > protocols
> > > that are needed?  Or just let the system handle the control path and
> > > handle the data path and sniff the control params from the system.
> > >
> > Like Morten, I'd be a bit concerned at the possible scope of the work
> > if we
> > start pulling in functionality from the IP stack like ARP etc. To avoid
> > this becoming a massive effort, how useful would it be if we just
> > limited
> > the scope to physical NIC setup only, and did not do anything above the
> > l2
> > layer?
>
> Think about it... Regardless of scope, this is clearly a control plane API, not a data plane API.
>
> It provides a proxy API for the O/S control plane (NETLINK in the case of Linux), so the DPDK application can use the user interface that the O/S already provides (e.g. "ip link set dev tap1 mtu 1600" etc.) for its control plane, instead of implementing its own CLI (or GUI or whatever).

Yes.

>
> In order to provide significant value, it will have to grow massively, so I can use it as imagined: To make a Linux firewall where the DPDK application handles the data plane, and the normal Linux commands are used for setting up the firewall, incl. firewall rules, port forwarding, NAPT, etc.. The Devil is in the details here!

Yes.
Another use case would be to handle exception where DPDK may not
handle all the traffic, Traffic such ARP can be redirected to OS. This
would enable DP to focus on the real fast path protocols such as IPv4,
UDP etc.

>
> Although I like the concept and idea behind it, I don't think a control plane proxy API belongs in DPDK. But it could possibly be hosted by the DPDK project if approved as such.

Why? rte_flow, rte_tm all control plane APIs and it is part of
DPDK.IMO, in order to have effective use of data plane, the control
plane has to be integrated together in an OS-independent way.

>
>
> Med venlig hilsen / kind regards
> - Morten Brørup