Re: [patch net-next RFC v2 0/6] introduce infrastructure for support of switch chip datapath

2014-03-26 14:44 GMT-07:00 Jamal Hadi Salim [off-list ref]:

Jiri,

The flow extensions may be distracting - note there are many
tables (L3, L2, etc) in such chips not just ACLs. And there's likely no
OneWay(tm) to add a flow. My view is probably to solve or reach an
agreement on the ports. Then resolve the different tables control/data
exposure.

Agreed.

On the switchdev - You are still exposing it; do you expect these
things to be created from user space? Probably thats one approach, but
I would suspect the majority would result in the driver itself creating
these devices after discovering the resources from the control
interfaces (PCIE etc).

It seems to me like, minus the strong MDIO dependency, DSA is probably
the closest and most ready piece of software we have in the kernel to
start building Ethernet switch port net_device as it already contains
pretty much everything we want:

- per-port ethtool operations
- per-port xmit/rcv handlers
- existing drivers

The missing bits are roughly:

- adding IFF_SWITCH_PORT flags to the slave net_device created
- creating the switch master net_device: sw1
- creating the Switch CPU port net_device: sw1p<N>

cheers,
jamal



On 03/26/14 12:31, Jiri Pirko wrote:

quoted

This is second version of RFC. Here are the main differences from the
first one:
-There is no special swdev of swport structure. The switch and its ports
are
  now represented only by net_device structures. There are couple of
switch-specific
  ndos added (inserting and removing flows).

-Regarding the flows, driver marks skb with "missing flow" flag now. That
would
  give indication to a user (OVS datapath of af_packet userspace
application).
  On the opposite direction, skb can be xmitted by a port.

-dummyswitch module has now rtnetlink iface for easy creation of dummy
switches
  and ports.

The basic idea is to introduce a generic infractructure to support various
switch chips in kernel. Also the idea is to benefit of currently existing
Open vSwitch userspace infrastructure.


The first two patches are just minor skb flag and packet_type
modifications.


The third patch does a split of structures which are not specific to OVS
into more generic ones that can be reused.


The fourth patch introduces the "switchdev" API itself. It should serve as
a glue between chip drivers on the one side and the user on the other.
That user might be OVS datapath but in future it might be just userspace
application interacting via af_packet and Netlink iface.

The infrastructure is designed to be similar to for example linux bridge.
There is one netdevice representing a switch chip and one netdevice per
every
port. These are bound together in classic slave-master way. The reason
to reuse the netdevices for port representation is that userspace can use
standard tools to get information about the ports, statistics, tcpdump,
etc.

Note that the netdevices are just representations of the ports in the
switch.
Therefore **no actual data** goes though, only missed flow skbs and, if
drivers
supports it, when ETH_P_ALL packet_type is hooked on (tcpdump).


The fifth patch introduces a support for switchdev vports into OVS
datapath.
After that, userspace would be able to create a switchdev DP for a switch
chip,
to add switchdev ports to it and to use it in the same way as it would be
OVS SW datapath.


The sixth patch adds a dummy switch module. It is just an example of
switchdev driver implementation.


Jiri Pirko (6):
   net: make packet_type->ak_packet_priv generic
   skbuff: add "missed_flow" flag
   openvswitch: split flow structures into ovs specific and generic ones
   net: introduce switchdev API
   openvswitch: Introduce support for switchdev based datapath
   net: introduce dummy switch

  drivers/net/Kconfig                        |   7 +
  drivers/net/Makefile                       |   1 +
  drivers/net/dummyswitch.c                  | 235
+++++++++++++++++++++++++++++
  include/linux/filter.h                     |   1 +
  include/linux/netdevice.h                  |  26 +++-
  include/linux/skbuff.h                     |  13 ++
  include/linux/sw_flow.h                    | 105 +++++++++++++
  include/linux/switchdev.h                  |  30 ++++
  include/uapi/linux/if_link.h               |   9 ++
  include/uapi/linux/openvswitch.h           |   4 +
  net/Kconfig                                |  10 ++
  net/core/Makefile                          |   1 +
  net/core/dev.c                             |   4 +-
  net/core/filter.c                          |   3 +
  net/core/switchdev.c                       | 172 +++++++++++++++++++++
  net/openvswitch/Makefile                   |   4 +
  net/openvswitch/datapath.c                 |  90 +++++++----
  net/openvswitch/datapath.h                 |  12 +-
  net/openvswitch/dp_notify.c                |   3 +-
  net/openvswitch/flow.c                     |  14 +-
  net/openvswitch/flow.h                     | 123 +++------------
  net/openvswitch/flow_netlink.c             |  24 +--
  net/openvswitch/flow_netlink.h             |   4 +-
  net/openvswitch/flow_table.c               | 100 ++++++------
  net/openvswitch/flow_table.h               |  18 +--
  net/openvswitch/vport-gre.c                |   4 +-
  net/openvswitch/vport-internal_switchdev.c | 179 ++++++++++++++++++++++
  net/openvswitch/vport-internal_switchdev.h |  28 ++++
  net/openvswitch/vport-netdev.c             |   4 +-
  net/openvswitch/vport-switchportdev.c      | 205
+++++++++++++++++++++++++
  net/openvswitch/vport-switchportdev.h      |  24 +++
  net/openvswitch/vport-vxlan.c              |   2 +-
  net/openvswitch/vport.c                    |   6 +-
  net/openvswitch/vport.h                    |   4 +-
  net/packet/af_packet.c                     |  22 ++-
  35 files changed, 1269 insertions(+), 222 deletions(-)
  create mode 100644 drivers/net/dummyswitch.c
  create mode 100644 include/linux/sw_flow.h
  create mode 100644 include/linux/switchdev.h
  create mode 100644 net/core/switchdev.c
  create mode 100644 net/openvswitch/vport-internal_switchdev.c
  create mode 100644 net/openvswitch/vport-internal_switchdev.h
  create mode 100644 net/openvswitch/vport-switchportdev.c
  create mode 100644 net/openvswitch/vport-switchportdev.h

-- 
Florian