[PATCH net-next 12/14] selftests: net: shaper: Reject invalid set requests

[Mohsin Bashir <mohsin.bashr@gmail.com>]

From: Mohsin Bashir <hmohsin@meta.com>

Verify that invalid set requests fail without corrupting existing queue
shaper state. The test covers invalid node creation through set and invalid
queue identifiers, then confirms the original queue configuration remains
unchanged.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Mohsin Bashir <hmohsin@meta.com>
---
 tools/testing/selftests/drivers/net/shaper.py | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/tools/testing/selftests/drivers/net/shaper.py b/tools/testing/selftests/drivers/net/shaper.py
index 8dd4897e999e..02a11e6b9a05 100755
--- a/tools/testing/selftests/drivers/net/shaper.py
+++ b/tools/testing/selftests/drivers/net/shaper.py
@@ -235,6 +235,46 @@ def set_all_supported_attrs(cfg, nl_shaper) -> None:
     shapers = nl_shaper.get({'ifindex': cfg.ifindex}, dump=True)
     ksft_eq(len(shapers), 0)
 
+def invalid_set_preserves_state(cfg, nl_shaper) -> None:
+    """ Verify a rejected .set leaves the existing shaper configuration unchanged. """
+    nq = _require_queues(cfg, 1)
+    _require_caps(cfg, nl_shaper, 'queue',
+                  ['support-bw-max', 'support-metric-bps'],
+                  "device does not support queue scope bw_max with bps metric")
+
+    initial = {'ifindex': cfg.ifindex,
+               'parent': {'scope': 'netdev'},
+               'handle': {'scope': 'queue', 'id': 0},
+               'metric': 'bps',
+               'bw-max': 10000}
+    nl_shaper.set({'ifindex': cfg.ifindex,
+                   'handle': {'scope': 'queue', 'id': 0},
+                   'metric': 'bps',
+                   'bw-max': 10000})
+    defer(_delete_shaper, cfg, nl_shaper, {'scope': 'queue', 'id': 0})
+
+    with ksft_raises(NlError):
+        nl_shaper.set({'ifindex': cfg.ifindex,
+                       'handle': {'scope': 'node', 'id': 0},
+                       'metric': 'bps',
+                       'bw-max': 20000})
+    shaper = nl_shaper.get({'ifindex': cfg.ifindex,
+                            'handle': {'scope': 'queue', 'id': 0}})
+    ksft_eq(shaper, initial)
+
+    with ksft_raises(NlError):
+        nl_shaper.set({'ifindex': cfg.ifindex,
+                       'handle': {'scope': 'queue', 'id': nq},
+                       'metric': 'bps',
+                       'bw-max': 20000})
+    shaper = nl_shaper.get({'ifindex': cfg.ifindex,
+                            'handle': {'scope': 'queue', 'id': 0}})
+    ksft_eq(shaper, initial)
+
+    _delete_shaper(cfg, nl_shaper, {'scope': 'queue', 'id': 0})
+    shapers = nl_shaper.get({'ifindex': cfg.ifindex}, dump=True)
+    ksft_eq(len(shapers), 0)
+
 def _group_under_netdev(cfg, nl_shaper, bw_max=None):
     r"""Group queues under a netdev-scope node; caller owns node teardown.
 
@@ -1152,6 +1192,7 @@ def main() -> None:
                   set_nshapers,
                   del_nshapers,
                   set_all_supported_attrs,
+                  invalid_set_preserves_state,
                   basic_groups,
                   basic_groups_with_rate,
                   qgroups,
-- 
2.53.0-Meta