netlink: specs: add partial specification for openvswitch

The openvswitch family has a fixed header, uses struct attrs and has array
values. This partial spec demonstrates these features in the YNL CLI. These
specs are sufficient to create, delete and dump datapaths and to dump vports:

$ ./tools/net/ynl/cli.py \
    --spec Documentation/netlink/specs/ovs_datapath.yaml \
    --do dp-new --json '{ "dp-ifindex": 0, "name": "demo", "upcall-pid": 0}'
None

$ ./tools/net/ynl/cli.py \
    --spec Documentation/netlink/specs/ovs_datapath.yaml \
    --dump dp-get --json '{ "dp-ifindex": 0 }'
[{'dp-ifindex': 3,
  'masks-cache-size': 256,
  'megaflow-stats': {'cache-hits': 0,
                     'mask-hit': 0,
                     'masks': 0,
                     'pad1': 0,
                     'padding': 0},
  'name': 'test',
  'stats': {'flows': 0, 'hit': 0, 'lost': 0, 'missed': 0},
  'user-features': {'dispatch-upcall-per-cpu',
                    'tc-recirc-sharing',
                    'unaligned'}},
 {'dp-ifindex': 48,
  'masks-cache-size': 256,
  'megaflow-stats': {'cache-hits': 0,
                     'mask-hit': 0,
                     'masks': 0,
                     'pad1': 0,
                     'padding': 0},
  'name': 'demo',
  'stats': {'flows': 0, 'hit': 0, 'lost': 0, 'missed': 0},
  'user-features': set()}]

$ ./tools/net/ynl/cli.py \
    --spec Documentation/netlink/specs/ovs_datapath.yaml \
    --do dp-del --json '{ "dp-ifindex": 0, "name": "demo"}'
None

$ ./tools/net/ynl/cli.py \
    --spec Documentation/netlink/specs/ovs_vport.yaml \
    --dump vport-get --json '{ "dp-ifindex": 3 }'
[{'dp-ifindex': 3,
  'ifindex': 3,
  'name': 'test',
  'port-no': 0,
  'stats': {'rx-bytes': 0,
            'rx-dropped': 0,
            'rx-errors': 0,
            'rx-packets': 0,
            'tx-bytes': 0,
            'tx-dropped': 0,
            'tx-errors': 0,
            'tx-packets': 0},
  'type': 'internal',
  'upcall-pid': [0],
  'upcall-stats': {'fail': 0, 'success': 0}}]
Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/specs/ovs_datapath.yaml

+# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+
+name: ovs_datapath
+version: 2
+protocol: genetlink-legacy
+
+doc:
+  OVS datapath configuration over generic netlink.
+
+definitions:
+  -
+    name: ovs-header
+    type: struct
+    members:
+      -
+        name: dp-ifindex
+        type: u32
+  -
+    name: user-features
+    type: flags
+    entries:
+      -
+        name: unaligned
+        doc: Allow last Netlink attribute to be unaligned
+      -
+        name: vport-pids
+        doc: Allow datapath to associate multiple Netlink PIDs to each vport
+      -
+        name: tc-recirc-sharing
+        doc: Allow tc offload recirc sharing
+      -
+        name: dispatch-upcall-per-cpu
+        doc: Allow per-cpu dispatch of upcalls
+  -
+    name: datapath-stats
+    type: struct
+    members:
+      -
+        name: hit
+        type: u64
+      -
+        name: missed
+        type: u64
+      -
+        name: lost
+        type: u64
+      -
+        name: flows
+        type: u64
+  -
+    name: megaflow-stats
+    type: struct
+    members:
+      -
+        name: mask-hit
+        type: u64
+      -
+        name: masks
+        type: u32
+      -
+        name: padding
+        type: u32
+      -
+        name: cache-hits
+        type: u64
+      -
+        name: pad1
+        type: u64
+
+attribute-sets:
+  -
+    name: datapath
+    attributes:
+      -
+        name: name
+        type: string
+      -
+        name: upcall-pid
+        doc: upcall pid
+        type: u32
+      -
+        name: stats
+        type: binary
+        struct: datapath-stats
+      -
+        name: megaflow-stats
+        type: binary
+        struct: megaflow-stats
+      -
+        name: user-features
+        type: u32
+        enum: user-features
+        enum-as-flags: true
+      -
+        name: pad
+        type: unused
+      -
+        name: masks-cache-size
+        type: u32
+      -
+        name: per-cpu-pids
+        type: binary
+        sub-type: u32
+
+operations:
+  fixed-header: ovs-header
+  list:
+    -
+      name: dp-get
+      doc: Get / dump OVS data path configuration and state
+      value: 3
+      attribute-set: datapath
+      do: &dp-get-op
+        request:
+          attributes:
+            - name
+        reply:
+          attributes:
+            - name
+            - upcall-pid
+            - stats
+            - megaflow-stats
+            - user-features
+            - masks-cache-size
+            - per-cpu-pids
+      dump: *dp-get-op
+    -
+      name: dp-new
+      doc: Create new OVS data path
+      value: 1
+      attribute-set: datapath
+      do:
+        request:
+          attributes:
+            - dp-ifindex
+            - name
+            - upcall-pid
+            - user-features
+    -
+      name: dp-del
+      doc: Delete existing OVS data path
+      value: 2
+      attribute-set: datapath
+      do:
+        request:
+          attributes:
+            - dp-ifindex
+            - name
+
+mcast-groups:
+  list:
+    -
+      name: ovs_datapath

Documentation/netlink/specs/ovs_vport.yaml

+# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+
+name: ovs_vport
+version: 2
+protocol: genetlink-legacy
+
+doc:
+  OVS vport configuration over generic netlink.
+
+definitions:
+  -
+    name: ovs-header
+    type: struct
+    members:
+      -
+        name: dp-ifindex
+        type: u32
+  -
+    name: vport-type
+    type: enum
+    entries: [ unspec, netdev, internal, gre, vxlan, geneve ]
+  -
+    name: vport-stats
+    type: struct
+    members:
+      -
+        name: rx-packets
+        type: u64
+      -
+        name: tx-packets
+        type: u64
+      -
+        name: rx-bytes
+        type: u64
+      -
+        name: tx-bytes
+        type: u64
+      -
+        name: rx-errors
+        type: u64
+      -
+        name: tx-errors
+        type: u64
+      -
+        name: rx-dropped
+        type: u64
+      -
+        name: tx-dropped
+        type: u64
+
+attribute-sets:
+  -
+    name: vport-options
+    attributes:
+      -
+        name: dst-port
+        type: u32
+      -
+        name: extension
+        type: u32
+  -
+    name: upcall-stats
+    attributes:
+      -
+        name: success
+        type: u64
+        value: 0
+      -
+        name: fail
+        type: u64
+  -
+    name: vport
+    attributes:
+      -
+        name: port-no
+        type: u32
+      -
+        name: type
+        type: u32
+        enum: vport-type
+      -
+        name: name
+        type: string
+      -
+        name: options
+        type: nest
+        nested-attributes: vport-options
+      -
+        name: upcall-pid
+        type: binary
+        sub-type: u32
+      -
+        name: stats
+        type: binary
+        struct: vport-stats
+      -
+        name: pad
+        type: unused
+      -
+        name: ifindex
+        type: u32
+      -
+        name: netnsid
+        type: u32
+      -
+        name: upcall-stats
+        type: nest
+        nested-attributes: upcall-stats
+
+operations:
+  list:
+    -
+      name: vport-get
+      doc: Get / dump OVS vport configuration and state
+      value: 3
+      attribute-set: vport
+      fixed-header: ovs-header
+      do: &vport-get-op
+        request:
+          attributes:
+            - dp-ifindex
+            - name
+        reply: &dev-all
+          attributes:
+            - dp-ifindex
+            - port-no
+            - type
+            - name
+            - upcall-pid
+            - stats
+            - ifindex
+            - netnsid
+            - upcall-stats
+      dump: *vport-get-op
+
+mcast-groups:
+  list:
+    -
+      name: ovs_vport