[RFC net-next 4/4] ynl: add a sample user for ethtool

[Jakub Kicinski <kuba@kernel.org>]

A sample schema describing ethtool channels and a script showing
that it works. The script is called like this:

 ./tools/net/ynl/samples/ethtool.py \
    --spec Documentation/netlink/bindings/ethtool.yaml \
    --device eth0

I have schemas for genetlink, FOU and the proposed DPLL subsystem,
to validate that the concept has wide applicability, but ethtool
feels like the best demo of the 4.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 Documentation/netlink/bindings/ethtool.yaml | 115 ++++++++++++++++++++
 tools/net/ynl/samples/ethtool.py            |  30 +++++
 2 files changed, 145 insertions(+)
 create mode 100644 Documentation/netlink/bindings/ethtool.yaml
 create mode 100755 tools/net/ynl/samples/ethtool.py

diff --git a/Documentation/netlink/bindings/ethtool.yaml b/Documentation/netlink/bindings/ethtool.yaml
new file mode 100644
index 000000000000..b4540d60b4b3
--- /dev/null
+++ b/Documentation/netlink/bindings/ethtool.yaml
@@ -0,0 +1,115 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+name: ethtool
+
+description: |
+  Ethernet device configuration interface.
+
+attr-cnt-suffix: CNT
+
+attribute-spaces:
+  -
+    name: header
+    name-prefix: ETHTOOL_A_HEADER_
+    attributes:
+      -
+        name: dev_index
+        val: 1
+        type: u32
+      -
+        name: dev_name
+        type: nul-string
+        len: ALTIFNAMSIZ - 1
+      -
+        name: flags
+        type: u32
+  -
+    name: channels
+    name-prefix: ETHTOOL_A_CHANNELS_
+    attributes:
+      -
+        name: header
+        val: 1
+        type: nest
+        nested-attributes: header
+      -
+        name: rx_max
+        type: u32
+      -
+        name: tx_max
+        type: u32
+      -
+        name: other_max
+        type: u32
+      -
+        name: combined_max
+        type: u32
+      -
+        name: rx_count
+        type: u32
+      -
+        name: tx_count
+        type: u32
+      -
+        name: other_count
+        type: u32
+      -
+        name: combined_count
+        type: u32
+
+headers:
+  user: linux/if.h
+  uapi: linux/ethtool_netlink.h
+
+operations:
+  name-prefix: ETHTOOL_MSG_
+  async-prefix: ETHTOOL_MSG_
+  list:
+    -
+      name: channels_get
+      val: 17
+      description: Get current and max supported number of channels.
+      attribute-space: channels
+      do:
+        request:
+          attributes:
+            - header
+        reply: &channel_reply
+          attributes:
+            - header
+            - rx_max
+            - tx_max
+            - other_max
+            - combined_max
+            - rx_count
+            - tx_count
+            - other_count
+            - combined_count
+      dump:
+        reply: *channel_reply
+
+    -
+      name: channels_ntf
+      description: Notification for device changing its number of channels.
+      notify: channels_get
+      mcgrp: monitor
+
+    -
+      name: channels_set
+      description: Set number of channels.
+      attribute-space: channels
+      do:
+        request:
+          attributes:
+            - header
+            - rx_count
+            - tx_count
+            - other_count
+            - combined_count
+
+mcast-groups:
+  name-prefix: ETHTOOL_MCGRP_
+  name-suffix: _NAME
+  list:
+    -
+      name: monitor
diff --git a/tools/net/ynl/samples/ethtool.py b/tools/net/ynl/samples/ethtool.py
new file mode 100755
index 000000000000..63c8e29f8e5d
--- /dev/null
+++ b/tools/net/ynl/samples/ethtool.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: BSD-3-Clause
+
+import argparse
+
+from ynl import YnlFamily
+
+
+def main():
+    parser = argparse.ArgumentParser(description='YNL ethtool sample')
+    parser.add_argument('--spec', dest='spec', type=str, required=True)
+    parser.add_argument('--schema', dest='schema', type=str)
+    parser.add_argument('--device', dest='dev_name', type=str)
+    parser.add_argument('--ifindex', dest='ifindex', type=str)
+    args = parser.parse_args()
+
+    ynl = YnlFamily(args.spec)
+
+    if args.dev_name:
+        channels = ynl.channels_get({'header': {'dev_name': args.dev_name}})
+    elif args.ifindex:
+        channels = ynl.channels_get({'header': {'dev_index': args.ifindex}})
+    else:
+        return
+    print('Netlink responded with:')
+    print(channels)
+
+
+if __name__ == "__main__":
+    main()
-- 
2.37.1