tools: ynl: cli: Add --list-attrs option to show operation attributes

Add a --list-attrs option to the YNL CLI that displays information about
netlink operations, including request and reply attributes.
This eliminates the need to manually inspect YAML spec files to
determine the JSON structure required for operations, or understand the
structure of the reply.

Example usage:
  # ./cli.py --family netdev --list-attrs dev-get
  Operation: dev-get
  Get / dump information about a netdev.

  Do request attributes:
    - ifindex: u32
      netdev ifindex

  Do reply attributes:
    - ifindex: u32
      netdev ifindex
    - xdp-features: u64 (enum: xdp-act)
      Bitmask of enabled xdp-features.
    - xdp-zc-max-segs: u32
      max fragment count supported by ZC driver
    - xdp-rx-metadata-features: u64 (enum: xdp-rx-metadata)
      Bitmask of supported XDP receive metadata features. See Documentation/networking/xdp-rx-metadata.rst for more details.
    - xsk-features: u64 (enum: xsk-flags)
      Bitmask of enabled AF_XDP features.

  Dump reply attributes:
    - ifindex: u32
      netdev ifindex
    - xdp-features: u64 (enum: xdp-act)
      Bitmask of enabled xdp-features.
    - xdp-zc-max-segs: u32
      max fragment count supported by ZC driver
    - xdp-rx-metadata-features: u64 (enum: xdp-rx-metadata)
      Bitmask of supported XDP receive metadata features. See Documentation/networking/xdp-rx-metadata.rst for more details.
    - xsk-features: u64 (enum: xsk-flags)
      Bitmask of enabled AF_XDP features.

Reviewed-by: Nimrod Oren <noren@nvidia.com>
Signed-off-by: Gal Pressman <gal@nvidia.com>
Link: https://patch.msgid.link/20251118143208.2380814-2-gal@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/tools/net/ynl/pyynl/cli.py b/tools/net/ynl/pyynl/cli.py
index 8c192e900bd3..4d91a2cee381 100755
--- a/tools/net/ynl/pyynl/cli.py
+++ b/tools/net/ynl/pyynl/cli.py
@@ -7,6 +7,7 @@ import os
 import pathlib
 import pprint
 import sys
+import textwrap
 
 sys.path.append(pathlib.Path(__file__).resolve().parent.as_posix())
 from lib import YnlFamily, Netlink, NlError
@@ -39,6 +40,37 @@ class YnlEncoder(json.JSONEncoder):
         return json.JSONEncoder.default(self, obj)
 
 
+def print_attr_list(attr_names, attr_set):
+    """Print a list of attributes with their types and documentation."""
+    for attr_name in attr_names:
+        if attr_name in attr_set.attrs:
+            attr = attr_set.attrs[attr_name]
+            attr_info = f'  - {attr_name}: {attr.type}'
+            if 'enum' in attr.yaml:
+                attr_info += f" (enum: {attr.yaml['enum']})"
+            if attr.yaml.get('doc'):
+                doc_text = textwrap.indent(attr.yaml['doc'], '    ')
+                attr_info += f"\n{doc_text}"
+            print(attr_info)
+
+
+def print_mode_attrs(mode, mode_spec, attr_set, print_request=True):
+    """Print a given mode (do/dump/event/notify)."""
+    mode_title = mode.capitalize()
+
+    if print_request and 'request' in mode_spec and 'attributes' in mode_spec['request']:
+        print(f'\n{mode_title} request attributes:')
+        print_attr_list(mode_spec['request']['attributes'], attr_set)
+
+    if 'reply' in mode_spec and 'attributes' in mode_spec['reply']:
+        print(f'\n{mode_title} reply attributes:')
+        print_attr_list(mode_spec['reply']['attributes'], attr_set)
+
+    if 'attributes' in mode_spec:
+        print(f'\n{mode_title} attributes:')
+        print_attr_list(mode_spec['attributes'], attr_set)
+
+
 def main():
     description = """
     YNL CLI utility - a general purpose netlink utility that uses YAML
@@ -70,6 +102,8 @@ def main():
     group.add_argument('--dump', dest='dump', metavar='DUMP-OPERATION', type=str)
     group.add_argument('--list-ops', action='store_true')
     group.add_argument('--list-msgs', action='store_true')
+    group.add_argument('--list-attrs', dest='list_attrs', metavar='OPERATION', type=str,
+                       help='List attributes for an operation')
 
     parser.add_argument('--duration', dest='duration', type=int,
                         help='when subscribed, watch for DURATION seconds')
@@ -135,6 +169,28 @@ def main():
         for op_name, op in ynl.msgs.items():
             print(op_name, " [", ", ".join(op.modes), "]")
 
+    if args.list_attrs:
+        op = ynl.msgs.get(args.list_attrs)
+        if not op:
+            print(f'Operation {args.list_attrs} not found')
+            exit(1)
+
+        print(f'Operation: {op.name}')
+        print(op.yaml['doc'])
+
+        for mode in ['do', 'dump', 'event']:
+            if mode in op.yaml:
+                print_mode_attrs(mode, op.yaml[mode], op.attr_set, True)
+
+        if 'notify' in op.yaml:
+            mode_spec = op.yaml['notify']
+            ref_spec = ynl.msgs.get(mode_spec).yaml.get('do')
+            if ref_spec:
+                print_mode_attrs('notify', ref_spec, op.attr_set, False)
+
+        if 'mcgrp' in op.yaml:
+            print(f"\nMulticast group: {op.yaml['mcgrp']}")
+
     try:
         if args.do:
             reply = ynl.do(args.do, attrs, args.flags)