[3/3] Spec-compliant CASE eviction policy algorithm

src/controller/python/test/test_scripts/base.py

@@ -370,7 +370,7 @@ async def TestCaseEviction(self, nodeid: int):
         # of eviction, just that allocation and CASE session establishment proceeds successfully on both
         # the controller and target.
         #
-        for x in range(minimumSupportedFabrics * minimumCASESessionsPerFabric * 3):
+        for x in range(minimumSupportedFabrics * minimumCASESessionsPerFabric * 2):
             self.devCtrl.CloseSession(nodeid)
             await self.devCtrl.ReadAttribute(nodeid, [(Clusters.Basic.Attributes.ClusterRevision)])
 
@@ -380,15 +380,94 @@ async def TestCaseEviction(self, nodeid: int):
         # This tests establishing a subscription on a given CASE session, then mark it defunct (to simulate
         # encountering a transport timeout on the session).
         #
-        # At the max interval, we should still have a valid subscription.
+        # Then, we write to an attribute from a *different* fabric and check to ensure we still get a report
+        # on the sub we established previously. Since it was just marked defunct, it should return back to being
+        # active and a report should get delivered.
+        #
+        sawValueChange = False
+
+        def OnValueChange(path: Attribute.TypedAttributePath, transaction: Attribute.SubscriptionTransaction) -> None:
+            nonlocal sawValueChange
+            self.logger.info("Saw value change!")
+            if (path.AttributeType == Clusters.TestCluster.Attributes.Int8u and path.Path.EndpointId == 1):
+                sawValueChange = True
+
+        self.logger.info("Testing CASE defunct logic")
+
+        sub = await self.devCtrl.ReadAttribute(nodeid, [(Clusters.TestCluster.Attributes.Int8u)], reportInterval=(0, 1))
+        sub.SetAttributeUpdateCallback(OnValueChange)
+
+        #
+        # This marks the session defunct.
         #
-        sub = await self.devCtrl.ReadAttribute(nodeid, [(Clusters.Basic.Attributes.ClusterRevision)], reportInterval=(0, 2))
-        await asyncio.sleep(2)
         self.devCtrl.CloseSession(nodeid)
-        await asyncio.sleep(4)
+
+        #
+        # Now write the attribute from fabric2, give it some time before checking if the report
+        # was received.
+        #
+        await self.devCtrl2.WriteAttribute(nodeid, [(1, Clusters.TestCluster.Attributes.Int8u(4))])
+        time.sleep(2)
 
         sub.Shutdown()
 
+        if sawValueChange is False:
+            self.logger.error("Didn't see value change in time, likely because sub got terminated due to unexpected session eviction!")
+            return False
+
+        #
+        # In this test, we're going to setup a subscription on fabric1 through devCtl, then, constantly keep
+        # evicting sessions on fabric2 (devCtl2) by cycling through closing sessions followed by issuing a Read. This
+        # should result in evictions on the server on fabric2, but not affect any sessions on fabric1. To test this,
+        # we're going to setup a subscription to an attribute prior to the cycling reads, and check at the end of the
+        # test that it's still valid by writing to an attribute from a *different* fabric, and validating that we see
+        # the change on the established subscription. That proves that the session from fabric1 is still valid and untouched.
+        #
+        self.logger.info("Testing fabric-isolated CASE eviction")
+
+        sawValueChange = False
+        sub = await self.devCtrl.ReadAttribute(nodeid, [(Clusters.TestCluster.Attributes.Int8u)], reportInterval=(0, 1))
+        sub.SetAttributeUpdateCallback(OnValueChange)
+
+        for x in range(minimumSupportedFabrics * minimumCASESessionsPerFabric * 2):
+            self.devCtrl2.CloseSession(nodeid)
+            await self.devCtrl2.ReadAttribute(nodeid, [(Clusters.Basic.Attributes.ClusterRevision)])
+
+        #
+        # Now write the attribute from fabric2, give it some time before checking if the report
+        # was received.
+        #
+        await self.devCtrl2.WriteAttribute(nodeid, [(1, Clusters.TestCluster.Attributes.Int8u(4))])
+        time.sleep(2)
+
+        sub.Shutdown()
+
+        if sawValueChange is False:
+            self.logger.error("Didn't see value change in time, likely because sub got terminated due to other fabric (fabric1)")
+            return False
+
+        #
+        # Do the same test again, but reversing the roles of fabric1 and fabric2.
+        #
+        self.logger.info("Testing fabric-isolated CASE eviction (reverse)")
+
+        sawValueChange = False
+        sub = await self.devCtrl2.ReadAttribute(nodeid, [(Clusters.TestCluster.Attributes.Int8u)], reportInterval=(0, 1))
+        sub.SetAttributeUpdateCallback(OnValueChange)
+
+        for x in range(minimumSupportedFabrics * minimumCASESessionsPerFabric * 2):
+            self.devCtrl.CloseSession(nodeid)
+            await self.devCtrl.ReadAttribute(nodeid, [(Clusters.Basic.Attributes.ClusterRevision)])
+
+        await self.devCtrl.WriteAttribute(nodeid, [(1, Clusters.TestCluster.Attributes.Int8u(4))])
+        time.sleep(2)
+
+        sub.Shutdown()
+
+        if sawValueChange is False:
+            self.logger.error("Didn't see value change in time, likely because sub got terminated due to other fabric (fabric2)")
+            return False
+
         return True
 
     async def TestMultiFabric(self, ip: str, setuppin: int, nodeid: int):

src/controller/python/test/test_scripts/mobile-device-test.py

@@ -76,24 +76,14 @@ def ethernet_commissioning(test: BaseTestHelper, discriminator: int, setup_pin:
                                      nodeid=device_nodeid),
               "Failed to finish key exchange")
 
-    #
-    # Run this before the MultiFabric test, since it will result in the resultant CASE session
-    # on fabric2 to be evicted (due to the stressful nature of that test) on the target.
-    #
-    # It doesn't actually evict the CASE session for fabric2 on the client, since we prioritize
-    # defunct sessions for eviction first, which means our CASE session on fabric2 remains preserved
-    # throughout the stress test. This results in a mis-match later.
-    #
-    # TODO: Once we implement fabric-adjusted LRU, we should see if this issue remains (it shouldn't)
-    #
-    logger.info("Testing CASE Eviction")
-    FailIfNot(asyncio.run(test.TestCaseEviction(device_nodeid)), "Failed TestCaseEviction")
-
     ok = asyncio.run(test.TestMultiFabric(ip=address,
                                           setuppin=20202021,
                                           nodeid=1))
     FailIfNot(ok, "Failed to commission multi-fabric")
 
+    logger.info("Testing CASE Eviction")
+    FailIfNot(asyncio.run(test.TestCaseEviction(device_nodeid)), "Failed TestCaseEviction")
+
     logger.info("Testing closing sessions")
     FailIfNot(test.TestCloseSession(nodeid=device_nodeid), "Failed to close sessions")
 

src/transport/SecureSession.h

@@ -302,6 +302,8 @@ class SecureSession : public Session, public ReferenceCounted<SecureSession, Sec
     void MoveToState(State targetState);
 
     friend class SecureSessionDeleter;
+    friend class TestSecureSessionTable;
+
     SecureSessionTable & mTable;
     State mState;
     const Type mSecureSessionType;