selftests/tc-testing: Add netem test case exercising loops

Add a netem nested duplicate test case to validate that it won't
cause an infinite loop

Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20260525122556.973584-10-jhs@mojatatu.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/netem.json b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/netem.json
index 3c4444961488c328110ffb49cd651385228e3352..472b672a600d9a8aaa71799a742e21f885a360d0 100644 (file)
--- a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/netem.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/netem.json
@@ -336,5 +336,36 @@
         "teardown": [
             "$TC qdisc del dev $DUMMY handle 1: root"
         ]
-    }
+    },
+    {
+        "id": "8c17",
+        "name": "Test netem's recursive duplicate",
+        "category": [
+            "qdisc",
+            "netem"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            "$IP link set dev $DUMMY up || true",
+            "$IP addr add 10.10.11.10/24 dev $DUMMY || true",
+            "$TC qdisc add dev $DUMMY root handle 1: netem limit 1000 duplicate 100%",
+            "$TC qdisc add dev $DUMMY parent 1: handle 2: netem limit 1000 duplicate 100%"
+        ],
+        "cmdUnderTest": "ping -c 1 10.10.11.11 -W 0.01",
+        "expExitCode": "1",
+        "verifyCmd": "$TC -s -j qdisc ls dev $DUMMY root",
+        "matchJSON": [
+            {
+                "kind": "netem",
+                "handle": "1:",
+                "bytes": 294,
+                "packets": 3
+            }
+        ],
+        "teardown": [
+            "$TC qdisc del dev $DUMMY handle 1: root"
+        ]
+     }
 ]