selftests/tc-testing: sfq: check perturb timer values

Add one test to check that the kernel rejects a negative perturb timer.

Add a second test checking that the kernel rejects
a too big perturb timer.

All test results:

1..2
ok 1 cdc1 - Check that a negative perturb timer is rejected
ok 2 a9f0 - Check that a too big perturb timer is rejected

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Reviewed-by: Cong Wang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: edumazet

tools/testing/selftests/tc-testing/tc-tests/qdiscs/sfq.json

@@ -264,5 +264,41 @@
         "matchPattern": "sfq",
         "matchCount": "0",
         "teardown": []
+    },
+    {
+        "id": "cdc1",
+        "name": "Check that a negative perturb timer is rejected",
+        "category": [
+            "qdisc",
+            "sfq"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [],
+        "cmdUnderTest": "$TC qdisc add dev $DUMMY handle 1: root sfq perturb -10",
+        "expExitCode": "2",
+        "verifyCmd": "$TC qdisc show dev $DUMMY",
+        "matchPattern": "sfq",
+        "matchCount": "0",
+        "teardown": []
+    },
+    {
+        "id": "a9f0",
+        "name": "Check that a too big perturb timer is rejected",
+        "category": [
+            "qdisc",
+            "sfq"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [],
+        "cmdUnderTest": "$TC qdisc add dev $DUMMY handle 1: root sfq perturb 1000000000",
+        "expExitCode": "2",
+        "verifyCmd": "$TC qdisc show dev $DUMMY",
+        "matchPattern": "sfq",
+        "matchCount": "0",
+        "teardown": []
     }
 ]