selftests: net: add scaffolding for Netlink tests in Python

Add glue code for accessing the YNL library which lives under
tools/net and YAML spec files from under Documentation/.
Automatically figure out if tests are run in tree or not.
Since we'll want to use this library both from net and
drivers/net test targets make the library a target as well,
and automatically include it when net or drivers/net are
included. Making net/lib a target ensures that we end up
with only one copy of it, and saves us some path guessing.

Add a tiny bit of formatting support to be able to output KTAP
from the start.

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 49 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/lib/py/ynl.py b/tools/testing/selftests/net/lib/py/ynl.py
new file mode 100644
index 000000000000..1ace58370c06
--- /dev/null
+++ b/tools/testing/selftests/net/lib/py/ynl.py
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0
+
+import sys
+from pathlib import Path
+from .consts import KSRC, KSFT_DIR
+from .ksft import ksft_pr, ktap_result
+
+# Resolve paths
+try:
+    if (KSFT_DIR / "kselftest-list.txt").exists():
+        # Running in "installed" selftests
+        tools_full_path = KSFT_DIR
+        SPEC_PATH = KSFT_DIR / "net/lib/specs"
+
+        sys.path.append(tools_full_path.as_posix())
+        from net.lib.ynl.lib import YnlFamily, NlError
+    else:
+        # Running in tree
+        tools_full_path = KSRC / "tools"
+        SPEC_PATH = KSRC / "Documentation/netlink/specs"
+
+        sys.path.append(tools_full_path.as_posix())
+        from net.ynl.lib import YnlFamily, NlError
+except ModuleNotFoundError as e:
+    ksft_pr("Failed importing `ynl` library from kernel sources")
+    ksft_pr(str(e))
+    ktap_result(True, comment="SKIP")
+    sys.exit(4)
+
+#
+# Wrapper classes, loading the right specs
+# Set schema='' to avoid jsonschema validation, it's slow
+#
+class EthtoolFamily(YnlFamily):
+    def __init__(self):
+        super().__init__((SPEC_PATH / Path('ethtool.yaml')).as_posix(),
+                         schema='')
+
+
+class RtnlFamily(YnlFamily):
+    def __init__(self):
+        super().__init__((SPEC_PATH / Path('rt_link.yaml')).as_posix(),
+                         schema='')
+
+
+class NetdevFamily(YnlFamily):
+    def __init__(self):
+        super().__init__((SPEC_PATH / Path('netdev.yaml')).as_posix(),
+                         schema='')