Re: [dpdk-dev] [PATCH 0/4] Introduce IF proxy library

[Jerin Jacob <jerinjacobk@gmail.com>]

On Thu, Apr 16, 2020 at 9:41 PM Stephen Hemminger
<stephen@networkplumber.org> wrote:
>
> On Fri, 6 Mar 2020 17:41:00 +0100
> Andrzej Ostruszka <aostruszka@marvell.com> wrote:
>
> > What is this useful for
> > =======================
> >
> > Usually, when an ethernet port is assigned to DPDK it vanishes from the
> > system and user looses ability to control it via normal configuration
> > utilities (e.g. those from iproute2 package).  Moreover by default DPDK
> > application is not aware of the network configuration of the system.
> >
> > To address both of these issues application needs to:
> > - add some command line interface (or other mechanism) allowing for
> >   control of the port and its configuration
> > - query the status of network configuration and monitor its changes
> >
> > The purpose of this library is to help with both of these tasks (as long
> > as they remain in domain of configuration available to the system).  In
> > other words, if DPDK application has some special needs, that cannot be
> > addressed by the normal system configuration utilities, then they need
> > to be solved by the application itself.
> >
> > The connection between DPDK and system is based on the existence of
> > ports that are visible to both DPDK and system (like Tap, KNI and
> > possibly some other drivers).  These ports serve as an interface
> > proxies.
> >
> > Let's visualize the action of the library by the following example:
> >
> >               Linux             |            DPDK
> > ==============================================================
> >                                 |
> >                                 |   +-------+       +-------+
> >                                 |   | Port1 |       | Port2 |
> > "ip link set dev tap1 mtu 1600" |   +-------+       +-------+
> >                           |     |       ^              ^ ^
> >                           |  +------+   | mtu_change   | |
> >                           `->| Tap1 |---' callback     | |
> >                              +------+                  | |
> > "ip addr add 198.51.100.14 \    |                      | |
> >                   dev tap2"     |                      | |
> >                           |  +------+                  | |
> >                           +->| Tap2 |------------------' |
> >                           |  +------+  addr_add callback |
> > "ip route add 198.0.2.0/24 \    |  |                     |
> >                   dev tap2"     |  | route_add callback  |
> >                                 |  `---------------------'
>
> Has anyone investigated solving this in the kernel rather than
> creating the added overhead of more Linux devices?
>
> What I am thinking of is a netlink to userspace interface.
> The kernel already has File-System-in-Userspace (FUSE) to allow
> for filesystems. What about having a NUSE (Netlink in userspace)?

IMO, there is no issue with the Linux Netlink _userspace_ interface.
The goal of IF proxy to abstract the OS differences so that it can
work with Linux, FreeBSD, and Windows(if needed).


>
> Then DPDK could have a daemon that is a provider to NUSE.
> This solution would also benefit other non-DPDK projects like VPP
> and allow DPDK to integrate with devlink etc.