[Cake] [PATCH net v6 2/2] selftests/tc-testing: Check Cake Scheduler when enqueue drops packets

[Xiang Mei <xmei5@asu.edu>]

Add tests that trigger packet drops in cake_enqueue(). The tests use
CAKE under a QFQ parent/class, then replace CAKE with NETEM to exercise
the previously fixed bug where cake_enqueue() drops a packet in the
same flow and returns NET_XMIT_CN.

Signed-off-by: Xiang Mei <xmei5@asu.edu>
---
 .../tc-testing/tc-tests/qdiscs/cake.json      | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/cake.json b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/cake.json
index c4c5f7ba0e0f..47ecd3fb1ea4 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/cake.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/cake.json
@@ -441,5 +441,33 @@
         "teardown": [
             "$TC qdisc del dev $DUMMY handle 1: root"
         ]
+    },
+    {
+	"id": "4366",
+	"name": "Enqueue CAKE with packets dropping",
+	"category": [
+	    "qdisc",
+	    "cake",
+	    "netem"
+	],
+	"plugins": {
+	    "requires": "nsPlugin"
+	},
+	"setup":[
+	    "$TC qdisc add dev $DUMMY handle 1: root qfq",
+	    "$TC class add dev $DUMMY parent 1: classid 1:1 qfq maxpkt 1024",
+	    "$TC qdisc add dev $DUMMY parent 1:1 handle 2: cake memlimit 9",
+	    "$TC filter add dev $DUMMY protocol ip parent 1: prio 1 u32 match ip protocol 1 0xff flowid 1:1",
+	    "ping -I$DUMMY -f -c1 -s64 -W1 10.10.10.1 || true",
+	    "$TC qdisc replace dev $DUMMY parent 1:1 handle 3: netem delay 0ms"
+	],
+	"cmdUnderTest": "ping -I$DUMMY -f -c1 -s64 -W1 10.10.10.1 || true",
+	"expExitCode": "0",
+	"verifyCmd": "$TC -s qdisc show dev $DUMMY",
+	"matchPattern": "qdisc qfq 1:",
+	"matchCount": "1",
+	"teardown": [
+	    "$TC qdisc del dev $DUMMY handle 1: root"
+	]
     }
 ]
-- 
2.43.0