diff --git a/framework/src/android/net/NetworkCapabilities.java b/framework/src/android/net/NetworkCapabilities.java
index 4254a66..feb9fc1 100644
--- a/framework/src/android/net/NetworkCapabilities.java
+++ b/framework/src/android/net/NetworkCapabilities.java
@@ -621,22 +621,22 @@
      * Network capabilities that are expected to be mutable, i.e., can change while a particular
      * network is connected.
      */
-    private static final long MUTABLE_CAPABILITIES =
+    private static final long MUTABLE_CAPABILITIES = NetworkCapabilitiesUtils.packBitList(
             // TRUSTED can change when user explicitly connects to an untrusted network in Settings.
             // http://b/18206275
-            (1 << NET_CAPABILITY_TRUSTED)
-            | (1 << NET_CAPABILITY_VALIDATED)
-            | (1 << NET_CAPABILITY_CAPTIVE_PORTAL)
-            | (1 << NET_CAPABILITY_NOT_ROAMING)
-            | (1 << NET_CAPABILITY_FOREGROUND)
-            | (1 << NET_CAPABILITY_NOT_CONGESTED)
-            | (1 << NET_CAPABILITY_NOT_SUSPENDED)
-            | (1 << NET_CAPABILITY_PARTIAL_CONNECTIVITY)
-            | (1 << NET_CAPABILITY_TEMPORARILY_NOT_METERED)
-            | (1 << NET_CAPABILITY_NOT_VCN_MANAGED)
+            NET_CAPABILITY_TRUSTED,
+            NET_CAPABILITY_VALIDATED,
+            NET_CAPABILITY_CAPTIVE_PORTAL,
+            NET_CAPABILITY_NOT_ROAMING,
+            NET_CAPABILITY_FOREGROUND,
+            NET_CAPABILITY_NOT_CONGESTED,
+            NET_CAPABILITY_NOT_SUSPENDED,
+            NET_CAPABILITY_PARTIAL_CONNECTIVITY,
+            NET_CAPABILITY_TEMPORARILY_NOT_METERED,
+            NET_CAPABILITY_NOT_VCN_MANAGED,
             // The value of NET_CAPABILITY_HEAD_UNIT is 32, which cannot use int to do bit shift,
             // otherwise there will be an overflow. Use long to do bit shift instead.
-            | (1L << NET_CAPABILITY_HEAD_UNIT);
+            NET_CAPABILITY_HEAD_UNIT);
 
     /**
      * Network capabilities that are not allowed in NetworkRequests. This exists because the
@@ -650,25 +650,26 @@
     // in an infinite loop about these.
     private static final long NON_REQUESTABLE_CAPABILITIES =
             MUTABLE_CAPABILITIES
-            & ~(1 << NET_CAPABILITY_TRUSTED)
-            & ~(1 << NET_CAPABILITY_NOT_VCN_MANAGED);
+            & ~(1L << NET_CAPABILITY_TRUSTED)
+            & ~(1L << NET_CAPABILITY_NOT_VCN_MANAGED);
 
     /**
      * Capabilities that are set by default when the object is constructed.
      */
-    private static final long DEFAULT_CAPABILITIES =
-            (1 << NET_CAPABILITY_NOT_RESTRICTED)
-            | (1 << NET_CAPABILITY_TRUSTED)
-            | (1 << NET_CAPABILITY_NOT_VPN);
+    private static final long DEFAULT_CAPABILITIES = NetworkCapabilitiesUtils.packBitList(
+            NET_CAPABILITY_NOT_RESTRICTED,
+            NET_CAPABILITY_TRUSTED,
+            NET_CAPABILITY_NOT_VPN);
 
     /**
      * Capabilities that are managed by ConnectivityService.
      */
     private static final long CONNECTIVITY_MANAGED_CAPABILITIES =
-            (1 << NET_CAPABILITY_VALIDATED)
-            | (1 << NET_CAPABILITY_CAPTIVE_PORTAL)
-            | (1 << NET_CAPABILITY_FOREGROUND)
-            | (1 << NET_CAPABILITY_PARTIAL_CONNECTIVITY);
+            NetworkCapabilitiesUtils.packBitList(
+                    NET_CAPABILITY_VALIDATED,
+                    NET_CAPABILITY_CAPTIVE_PORTAL,
+                    NET_CAPABILITY_FOREGROUND,
+                    NET_CAPABILITY_PARTIAL_CONNECTIVITY);
 
     /**
      * Capabilities that are allowed for test networks. This list must be set so that it is safe
@@ -677,14 +678,15 @@
      * INTERNET, IMS, SUPL, etc.
      */
     private static final long TEST_NETWORKS_ALLOWED_CAPABILITIES =
-            (1 << NET_CAPABILITY_NOT_METERED)
-            | (1 << NET_CAPABILITY_TEMPORARILY_NOT_METERED)
-            | (1 << NET_CAPABILITY_NOT_RESTRICTED)
-            | (1 << NET_CAPABILITY_NOT_VPN)
-            | (1 << NET_CAPABILITY_NOT_ROAMING)
-            | (1 << NET_CAPABILITY_NOT_CONGESTED)
-            | (1 << NET_CAPABILITY_NOT_SUSPENDED)
-            | (1 << NET_CAPABILITY_NOT_VCN_MANAGED);
+            NetworkCapabilitiesUtils.packBitList(
+            NET_CAPABILITY_NOT_METERED,
+            NET_CAPABILITY_TEMPORARILY_NOT_METERED,
+            NET_CAPABILITY_NOT_RESTRICTED,
+            NET_CAPABILITY_NOT_VPN,
+            NET_CAPABILITY_NOT_ROAMING,
+            NET_CAPABILITY_NOT_CONGESTED,
+            NET_CAPABILITY_NOT_SUSPENDED,
+            NET_CAPABILITY_NOT_VCN_MANAGED);
 
     /**
      * Adds the given capability to this {@code NetworkCapability} instance.
@@ -1156,12 +1158,13 @@
     /**
      * Allowed transports on an unrestricted test network (in addition to TRANSPORT_TEST).
      */
-    private static final int UNRESTRICTED_TEST_NETWORKS_ALLOWED_TRANSPORTS =
-            1 << TRANSPORT_TEST
-            // Test ethernet networks can be created with EthernetManager#setIncludeTestInterfaces
-            | 1 << TRANSPORT_ETHERNET
-            // Test VPN networks can be created but their UID ranges must be empty.
-            | 1 << TRANSPORT_VPN;
+    private static final long UNRESTRICTED_TEST_NETWORKS_ALLOWED_TRANSPORTS =
+            NetworkCapabilitiesUtils.packBitList(
+                    TRANSPORT_TEST,
+                    // Test eth networks are created with EthernetManager#setIncludeTestInterfaces
+                    TRANSPORT_ETHERNET,
+                    // Test VPN networks can be created but their UID ranges must be empty.
+                    TRANSPORT_VPN);
 
     /**
      * Adds the given transport type to this {@code NetworkCapability} instance.
@@ -3076,4 +3079,4 @@
             return new NetworkCapabilities(mCaps);
         }
     }
-}
+}
\ No newline at end of file
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index fb90053..a9a06e4 100644
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -1339,6 +1339,18 @@
         }
 
         /**
+         * @see CarrierPrivilegeAuthenticator
+         */
+        public CarrierPrivilegeAuthenticator makeCarrierPrivilegeAuthenticator(
+                @NonNull final Context context, @NonNull final TelephonyManager tm) {
+            if (SdkLevel.isAtLeastT()) {
+                return new CarrierPrivilegeAuthenticator(context, tm);
+            } else {
+                return null;
+            }
+        }
+
+        /**
          * @see DeviceConfigUtils#isFeatureEnabled
          */
         public boolean isFeatureEnabled(Context context, String name, boolean defaultEnabled) {
@@ -1426,12 +1438,8 @@
         mTelephonyManager = (TelephonyManager) mContext.getSystemService(Context.TELEPHONY_SERVICE);
         mAppOpsManager = (AppOpsManager) mContext.getSystemService(Context.APP_OPS_SERVICE);
         mLocationPermissionChecker = mDeps.makeLocationPermissionChecker(mContext);
-        if (SdkLevel.isAtLeastT()) {
-            mCarrierPrivilegeAuthenticator =
-                    new CarrierPrivilegeAuthenticator(mContext, mTelephonyManager);
-        } else {
-            mCarrierPrivilegeAuthenticator = null;
-        }
+        mCarrierPrivilegeAuthenticator =
+                mDeps.makeCarrierPrivilegeAuthenticator(mContext, mTelephonyManager);
 
         // To ensure uid state is synchronized with Network Policy, register for
         // NetworkPolicyManagerService events must happen prior to NetworkPolicyManagerService
@@ -4157,11 +4165,11 @@
         }
     }
 
-    private boolean hasCarrierPrivilegeForNetworkRequest(int callingUid,
-            NetworkRequest networkRequest) {
+    private boolean hasCarrierPrivilegeForNetworkCaps(final int callingUid,
+            @NonNull final NetworkCapabilities caps) {
         if (SdkLevel.isAtLeastT() && mCarrierPrivilegeAuthenticator != null) {
-            return mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkRequest(callingUid,
-                    networkRequest);
+            return mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                    callingUid, caps);
         }
         return false;
     }
@@ -4205,7 +4213,7 @@
                     }
                 }
                 if (req.hasCapability(NetworkCapabilities.NET_CAPABILITY_CBS)) {
-                    if (!hasCarrierPrivilegeForNetworkRequest(nri.mUid, req)
+                    if (!hasCarrierPrivilegeForNetworkCaps(nri.mUid, req.networkCapabilities)
                             && !checkConnectivityRestrictedNetworksPermission(
                                     nri.mPid, nri.mUid)) {
                         requestToBeReleased = req;
@@ -6140,13 +6148,6 @@
         }
     }
 
-    private void ensureRequestableCapabilities(NetworkCapabilities networkCapabilities) {
-        final String badCapability = networkCapabilities.describeFirstNonRequestableCapability();
-        if (badCapability != null) {
-            throw new IllegalArgumentException("Cannot request network with " + badCapability);
-        }
-    }
-
     // This checks that the passed capabilities either do not request a
     // specific SSID/SignalStrength, or the calling app has permission to do so.
     private void ensureSufficientPermissionsForRequest(NetworkCapabilities nc,
@@ -6204,7 +6205,7 @@
         nai.onSignalStrengthThresholdsUpdated(thresholdsArray);
     }
 
-    private void ensureValidNetworkSpecifier(NetworkCapabilities nc) {
+    private static void ensureValidNetworkSpecifier(NetworkCapabilities nc) {
         if (nc == null) {
             return;
         }
@@ -6217,7 +6218,7 @@
         }
     }
 
-    private void ensureValid(NetworkCapabilities nc) {
+    private static void ensureListenableCapabilities(@NonNull final NetworkCapabilities nc) {
         ensureValidNetworkSpecifier(nc);
         if (nc.isPrivateDnsBroken()) {
             throw new IllegalArgumentException("Can't request broken private DNS");
@@ -6227,6 +6228,14 @@
         }
     }
 
+    private void ensureRequestableCapabilities(@NonNull final NetworkCapabilities nc) {
+        ensureListenableCapabilities(nc);
+        final String badCapability = nc.describeFirstNonRequestableCapability();
+        if (badCapability != null) {
+            throw new IllegalArgumentException("Cannot request network with " + badCapability);
+        }
+    }
+
     // TODO: Set the mini sdk to 31 and remove @TargetApi annotation when b/205923322 is addressed.
     @TargetApi(Build.VERSION_CODES.S)
     private boolean isTargetSdkAtleast(int version, int callingUid,
@@ -6319,7 +6328,6 @@
         if (timeoutMs < 0) {
             throw new IllegalArgumentException("Bad timeout specified");
         }
-        ensureValid(networkCapabilities);
 
         final NetworkRequest networkRequest = new NetworkRequest(networkCapabilities, legacyType,
                 nextNetworkRequestId(), reqType);
@@ -6461,7 +6469,6 @@
                 Binder.getCallingPid(), callingUid, callingPackageName);
         restrictRequestUidsForCallerAndSetRequestorInfo(networkCapabilities,
                 callingUid, callingPackageName);
-        ensureValid(networkCapabilities);
 
         NetworkRequest networkRequest = new NetworkRequest(networkCapabilities, TYPE_NONE,
                 nextNetworkRequestId(), NetworkRequest.Type.REQUEST);
@@ -6528,7 +6535,7 @@
         // There is no need to do this for requests because an app without CHANGE_NETWORK_STATE
         // can't request networks.
         restrictBackgroundRequestForCaller(nc);
-        ensureValid(nc);
+        ensureListenableCapabilities(nc);
 
         NetworkRequest networkRequest = new NetworkRequest(nc, TYPE_NONE, nextNetworkRequestId(),
                 NetworkRequest.Type.LISTEN);
@@ -6550,7 +6557,7 @@
         if (!hasWifiNetworkListenPermission(networkCapabilities)) {
             enforceAccessPermission();
         }
-        ensureValid(networkCapabilities);
+        ensureListenableCapabilities(networkCapabilities);
         ensureSufficientPermissionsForRequest(networkCapabilities,
                 Binder.getCallingPid(), callingUid, callingPackageName);
         final NetworkCapabilities nc = new NetworkCapabilities(networkCapabilities);
@@ -7495,7 +7502,8 @@
             nc.setOwnerUid(nai.networkCapabilities.getOwnerUid());
         }
         nai.declaredCapabilities = new NetworkCapabilities(nc);
-        NetworkAgentInfo.restrictCapabilitiesFromNetworkAgent(nc, nai.creatorUid);
+        NetworkAgentInfo.restrictCapabilitiesFromNetworkAgent(nc, nai.creatorUid,
+                mCarrierPrivilegeAuthenticator);
     }
 
     /** Modifies |newNc| based on the capabilities of |underlyingNetworks| and |agentCaps|. */
diff --git a/service/src/com/android/server/connectivity/CarrierPrivilegeAuthenticator.java b/service/src/com/android/server/connectivity/CarrierPrivilegeAuthenticator.java
index c5107ad..ce955fd 100644
--- a/service/src/com/android/server/connectivity/CarrierPrivilegeAuthenticator.java
+++ b/service/src/com/android/server/connectivity/CarrierPrivilegeAuthenticator.java
@@ -17,6 +17,7 @@
 package com.android.server.connectivity;
 
 import static android.net.NetworkCapabilities.NET_CAPABILITY_CBS;
+import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
 
 import android.annotation.NonNull;
 import android.content.BroadcastReceiver;
@@ -25,7 +26,7 @@
 import android.content.IntentFilter;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
-import android.net.NetworkRequest;
+import android.net.NetworkCapabilities;
 import android.net.NetworkSpecifier;
 import android.net.TelephonyNetworkSpecifier;
 import android.os.Build;
@@ -235,24 +236,30 @@
     }
 
     /**
-     * Check if network request is allowed based upon carrrier service package.
+     * Check if a UID is the carrier service app of the subscription ID in the provided capabilities
      *
-     * Network request for {@link NET_CAPABILITY_CBS} is allowed if the caller has
-     * carrier privilege and provides the carrier config. This function checks if caller
-     * has the same and returns true if it has else false.
+     * This returns whether the passed UID is the carrier service package for the subscription ID
+     * stored in the telephony network specifier in the passed network capabilities.
+     * If the capabilities don't code for a cellular network, or if they don't have the
+     * subscription ID in their specifier, this returns false.
      *
-     * @param callingUid user identifier that uniquely identifies the caller.
-     * @param networkRequest the network request for which the carrier privilege is checked.
-     * @return true if caller has carrier privilege and provides the carrier config else false.
+     * This method can be used to check that a network request for {@link NET_CAPABILITY_CBS} is
+     * allowed for the UID of a caller, which must hold carrier privilege and provide the carrier
+     * config.
+     * It can also be used to check that a factory is entitled to grant access to a given network
+     * to a given UID on grounds that it is the carrier service package.
+     *
+     * @param callingUid uid of the app claimed to be the carrier service package.
+     * @param networkCapabilities the network capabilities for which carrier privilege is checked.
+     * @return true if uid provides the relevant carrier config else false.
      */
-    public boolean hasCarrierPrivilegeForNetworkRequest(int callingUid,
-            NetworkRequest networkRequest) {
-        if (callingUid != Process.INVALID_UID) {
-            final int subId = getSubIdFromNetworkSpecifier(
-                    networkRequest.getNetworkSpecifier());
-            return callingUid == getCarrierServiceUidForSubId(subId);
-        }
-        return false;
+    public boolean hasCarrierPrivilegeForNetworkCapabilities(int callingUid,
+            @NonNull NetworkCapabilities networkCapabilities) {
+        if (callingUid == Process.INVALID_UID) return false;
+        if (!networkCapabilities.hasSingleTransport(TRANSPORT_CELLULAR)) return false;
+        final int subId = getSubIdFromNetworkSpecifier(networkCapabilities.getNetworkSpecifier());
+        if (SubscriptionManager.INVALID_SUBSCRIPTION_ID == subId) return false;
+        return callingUid == getCarrierServiceUidForSubId(subId);
     }
 
     @VisibleForTesting
@@ -286,7 +293,7 @@
         if (specifier instanceof TelephonyNetworkSpecifier) {
             return ((TelephonyNetworkSpecifier) specifier).getSubscriptionId();
         }
-        return SubscriptionManager.DEFAULT_SUBSCRIPTION_ID;
+        return SubscriptionManager.INVALID_SUBSCRIPTION_ID;
     }
 
     @VisibleForTesting
diff --git a/service/src/com/android/server/connectivity/NetworkAgentInfo.java b/service/src/com/android/server/connectivity/NetworkAgentInfo.java
index b9e2a5f..e917b3f 100644
--- a/service/src/com/android/server/connectivity/NetworkAgentInfo.java
+++ b/service/src/com/android/server/connectivity/NetworkAgentInfo.java
@@ -60,6 +60,7 @@
 import android.util.SparseArray;
 
 import com.android.internal.util.WakeupMessage;
+import com.android.modules.utils.build.SdkLevel;
 import com.android.server.ConnectivityService;
 
 import java.io.PrintWriter;
@@ -1196,21 +1197,26 @@
      *
      * @param nc the capabilities to sanitize
      * @param creatorUid the UID of the process creating this network agent
+     * @param authenticator the carrier privilege authenticator to check for telephony constraints
      */
     public static void restrictCapabilitiesFromNetworkAgent(@NonNull final NetworkCapabilities nc,
-            final int creatorUid) {
+            final int creatorUid, @NonNull final CarrierPrivilegeAuthenticator authenticator) {
         if (nc.hasTransport(TRANSPORT_TEST)) {
             nc.restrictCapabilitiesForTestNetwork(creatorUid);
         }
-        if (!areAccessUidsAcceptableFromNetworkAgent(nc)) {
+        if (!areAccessUidsAcceptableFromNetworkAgent(nc, authenticator)) {
             nc.setAccessUids(new ArraySet<>());
         }
     }
 
     private static boolean areAccessUidsAcceptableFromNetworkAgent(
-            @NonNull final NetworkCapabilities nc) {
+            @NonNull final NetworkCapabilities nc,
+            @Nullable final CarrierPrivilegeAuthenticator carrierPrivilegeAuthenticator) {
         // NCs without access UIDs are fine.
         if (!nc.hasAccessUids()) return true;
+        // S and below must never accept access UIDs, even if an agent sends them, because netd
+        // didn't support the required feature in S.
+        if (!SdkLevel.isAtLeastT()) return false;
 
         // On a non-restricted network, access UIDs make no sense
         if (nc.hasCapability(NET_CAPABILITY_NOT_RESTRICTED)) return false;
@@ -1219,7 +1225,18 @@
         // access UIDs
         if (nc.hasTransport(TRANSPORT_TEST)) return true;
 
-        // TODO : accept more supported cases
+        // Factories that make cell networks can allow the UID for the carrier service package.
+        // This can only work in T where there is support for CarrierPrivilegeAuthenticator
+        if (null != carrierPrivilegeAuthenticator
+                && nc.hasSingleTransport(TRANSPORT_CELLULAR)
+                && (1 == nc.getAccessUidsNoCopy().size())
+                && (carrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                        nc.getAccessUidsNoCopy().valueAt(0), nc))) {
+            return true;
+        }
+
+        // TODO : accept Railway callers
+
         return false;
     }
 
diff --git a/tests/unit/java/com/android/server/ConnectivityServiceTest.java b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
index e41a2ac..0132525 100644
--- a/tests/unit/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
@@ -264,6 +264,7 @@
 import android.net.RouteInfo;
 import android.net.RouteInfoParcel;
 import android.net.SocketKeepalive;
+import android.net.TelephonyNetworkSpecifier;
 import android.net.TransportInfo;
 import android.net.UidRange;
 import android.net.UidRangeParcel;
@@ -334,6 +335,7 @@
 import com.android.server.ConnectivityService.ConnectivityDiagnosticsCallbackInfo;
 import com.android.server.ConnectivityService.NetworkRequestInfo;
 import com.android.server.ConnectivityServiceTest.ConnectivityServiceDependencies.ReportedInterfaces;
+import com.android.server.connectivity.CarrierPrivilegeAuthenticator;
 import com.android.server.connectivity.ConnectivityFlags;
 import com.android.server.connectivity.MockableSystemProperties;
 import com.android.server.connectivity.Nat464Xlat;
@@ -529,6 +531,7 @@
     @Mock Resources mResources;
     @Mock PacProxyManager mPacProxyManager;
     @Mock BpfNetMaps mBpfNetMaps;
+    @Mock CarrierPrivilegeAuthenticator mCarrierPrivilegeAuthenticator;
 
     // BatteryStatsManager is final and cannot be mocked with regular mockito, so just mock the
     // underlying binder calls.
@@ -970,8 +973,6 @@
          * @param hasInternet Indicate if network should pretend to have NET_CAPABILITY_INTERNET.
          */
         public void connect(boolean validated, boolean hasInternet, boolean isStrictMode) {
-            assertFalse(getNetworkCapabilities().hasCapability(NET_CAPABILITY_INTERNET));
-
             ConnectivityManager.NetworkCallback callback = null;
             final ConditionVariable validatedCv = new ConditionVariable();
             if (validated) {
@@ -1859,6 +1860,12 @@
         }
 
         @Override
+        public CarrierPrivilegeAuthenticator makeCarrierPrivilegeAuthenticator(
+                @NonNull final Context context, @NonNull final TelephonyManager tm) {
+            return SdkLevel.isAtLeastT() ? mCarrierPrivilegeAuthenticator : null;
+        }
+
+        @Override
         public boolean intentFilterEquals(final PendingIntent a, final PendingIntent b) {
             return runAsShell(GET_INTENT_SENDER_INTENT, () -> a.intentFilterEquals(b));
         }
@@ -14643,43 +14650,157 @@
                 agent.getNetwork().getNetId(),
                 intToUidRangeStableParcels(uids),
                 preferenceOrder);
-        inOrder.verify(mMockNetd, times(1)).networkAddUidRangesParcel(uids200Parcel);
+        if (SdkLevel.isAtLeastT()) {
+            inOrder.verify(mMockNetd, times(1)).networkAddUidRangesParcel(uids200Parcel);
+        }
 
         uids.add(300);
         uids.add(400);
         nc.setAccessUids(uids);
         agent.setNetworkCapabilities(nc, true /* sendToConnectivityService */);
-        cb.expectCapabilitiesThat(agent, caps -> caps.getAccessUids().equals(uids));
+        if (SdkLevel.isAtLeastT()) {
+            cb.expectCapabilitiesThat(agent, caps -> caps.getAccessUids().equals(uids));
+        } else {
+            cb.assertNoCallback();
+        }
 
         uids.remove(200);
         final NativeUidRangeConfig uids300400Parcel = new NativeUidRangeConfig(
                 agent.getNetwork().getNetId(),
                 intToUidRangeStableParcels(uids),
                 preferenceOrder);
-        inOrder.verify(mMockNetd, times(1)).networkAddUidRangesParcel(uids300400Parcel);
+        if (SdkLevel.isAtLeastT()) {
+            inOrder.verify(mMockNetd, times(1)).networkAddUidRangesParcel(uids300400Parcel);
+        }
 
         nc.setAccessUids(uids);
         agent.setNetworkCapabilities(nc, true /* sendToConnectivityService */);
-        cb.expectCapabilitiesThat(agent, caps -> caps.getAccessUids().equals(uids));
-        inOrder.verify(mMockNetd, times(1)).networkRemoveUidRangesParcel(uids200Parcel);
+        if (SdkLevel.isAtLeastT()) {
+            cb.expectCapabilitiesThat(agent, caps -> caps.getAccessUids().equals(uids));
+            inOrder.verify(mMockNetd, times(1)).networkRemoveUidRangesParcel(uids200Parcel);
+        } else {
+            cb.assertNoCallback();
+        }
 
         uids.clear();
         uids.add(600);
         nc.setAccessUids(uids);
         agent.setNetworkCapabilities(nc, true /* sendToConnectivityService */);
-        cb.expectCapabilitiesThat(agent, caps -> caps.getAccessUids().equals(uids));
+        if (SdkLevel.isAtLeastT()) {
+            cb.expectCapabilitiesThat(agent, caps -> caps.getAccessUids().equals(uids));
+        } else {
+            cb.assertNoCallback();
+        }
         final NativeUidRangeConfig uids600Parcel = new NativeUidRangeConfig(
                 agent.getNetwork().getNetId(),
                 intToUidRangeStableParcels(uids),
                 preferenceOrder);
-        inOrder.verify(mMockNetd, times(1)).networkAddUidRangesParcel(uids600Parcel);
-        inOrder.verify(mMockNetd, times(1)).networkRemoveUidRangesParcel(uids300400Parcel);
+        if (SdkLevel.isAtLeastT()) {
+            inOrder.verify(mMockNetd, times(1)).networkAddUidRangesParcel(uids600Parcel);
+            inOrder.verify(mMockNetd, times(1)).networkRemoveUidRangesParcel(uids300400Parcel);
+        }
 
         uids.clear();
         nc.setAccessUids(uids);
         agent.setNetworkCapabilities(nc, true /* sendToConnectivityService */);
-        cb.expectCapabilitiesThat(agent, caps -> caps.getAccessUids().isEmpty());
-        inOrder.verify(mMockNetd, times(1)).networkRemoveUidRangesParcel(uids600Parcel);
+        if (SdkLevel.isAtLeastT()) {
+            cb.expectCapabilitiesThat(agent, caps -> caps.getAccessUids().isEmpty());
+            inOrder.verify(mMockNetd, times(1)).networkRemoveUidRangesParcel(uids600Parcel);
+        } else {
+            cb.assertNoCallback();
+            verify(mMockNetd, never()).networkAddUidRangesParcel(any());
+            verify(mMockNetd, never()).networkRemoveUidRangesParcel(any());
+        }
+
+    }
+
+    @Test
+    public void testCbsAccessUids() throws Exception {
+        mServiceContext.setPermission(NETWORK_FACTORY, PERMISSION_GRANTED);
+        mServiceContext.setPermission(MANAGE_TEST_NETWORKS, PERMISSION_GRANTED);
+
+        // In this test TEST_PACKAGE_UID will be the UID of the carrier service UID.
+        doReturn(true).when(mCarrierPrivilegeAuthenticator)
+                .hasCarrierPrivilegeForNetworkCapabilities(eq(TEST_PACKAGE_UID), any());
+
+        final ArraySet<Integer> serviceUidSet = new ArraySet<>();
+        serviceUidSet.add(TEST_PACKAGE_UID);
+        final ArraySet<Integer> nonServiceUidSet = new ArraySet<>();
+        nonServiceUidSet.add(TEST_PACKAGE_UID2);
+        final ArraySet<Integer> serviceUidSetPlus = new ArraySet<>();
+        serviceUidSetPlus.add(TEST_PACKAGE_UID);
+        serviceUidSetPlus.add(TEST_PACKAGE_UID2);
+
+        final TestNetworkCallback cb = new TestNetworkCallback();
+
+        // Simulate a restricted telephony network. The telephony factory is entitled to set
+        // the access UID to the service package on any of its restricted networks.
+        final NetworkCapabilities.Builder ncb = new NetworkCapabilities.Builder()
+                .addTransportType(TRANSPORT_CELLULAR)
+                .addCapability(NET_CAPABILITY_INTERNET)
+                .addCapability(NET_CAPABILITY_NOT_SUSPENDED)
+                .addCapability(NET_CAPABILITY_NOT_VCN_MANAGED)
+                .removeCapability(NET_CAPABILITY_NOT_RESTRICTED)
+                .setNetworkSpecifier(new TelephonyNetworkSpecifier(1 /* subid */));
+
+        // Cell gets to set the service UID as access UID
+        mCm.requestNetwork(new NetworkRequest.Builder()
+                .addTransportType(TRANSPORT_CELLULAR)
+                .removeCapability(NET_CAPABILITY_NOT_RESTRICTED)
+                .build(), cb);
+        mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR,
+                new LinkProperties(), ncb.build());
+        mCellNetworkAgent.connect(true);
+        cb.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
+        ncb.setAccessUids(serviceUidSet);
+        mCellNetworkAgent.setNetworkCapabilities(ncb.build(), true /* sendToCS */);
+        if (SdkLevel.isAtLeastT()) {
+            cb.expectCapabilitiesThat(mCellNetworkAgent,
+                    caps -> caps.getAccessUids().equals(serviceUidSet));
+        } else {
+            // S must ignore access UIDs.
+            cb.assertNoCallback(TEST_CALLBACK_TIMEOUT_MS);
+        }
+
+        // ...but not to some other UID. Rejection sets UIDs to the empty set
+        ncb.setAccessUids(nonServiceUidSet);
+        mCellNetworkAgent.setNetworkCapabilities(ncb.build(), true /* sendToCS */);
+        if (SdkLevel.isAtLeastT()) {
+            cb.expectCapabilitiesThat(mCellNetworkAgent,
+                    caps -> caps.getAccessUids().isEmpty());
+        } else {
+            // S must ignore access UIDs.
+            cb.assertNoCallback(TEST_CALLBACK_TIMEOUT_MS);
+        }
+
+        // ...and also not to multiple UIDs even including the service UID
+        ncb.setAccessUids(serviceUidSetPlus);
+        mCellNetworkAgent.setNetworkCapabilities(ncb.build(), true /* sendToCS */);
+        cb.assertNoCallback(TEST_CALLBACK_TIMEOUT_MS);
+
+        mCellNetworkAgent.disconnect();
+        cb.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
+        mCm.unregisterNetworkCallback(cb);
+
+        // Must be unset before touching the transports, because remove and add transport types
+        // check the specifier on the builder immediately, contradicting normal builder semantics
+        // TODO : fix the builder
+        ncb.setNetworkSpecifier(null);
+        ncb.removeTransportType(TRANSPORT_CELLULAR);
+        ncb.addTransportType(TRANSPORT_WIFI);
+        // Wifi does not get to set access UID, even to the correct UID
+        mCm.requestNetwork(new NetworkRequest.Builder()
+                .addTransportType(TRANSPORT_WIFI)
+                .removeCapability(NET_CAPABILITY_NOT_RESTRICTED)
+                .build(), cb);
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI,
+                new LinkProperties(), ncb.build());
+        mWiFiNetworkAgent.connect(true);
+        cb.expectAvailableThenValidatedCallbacks(mWiFiNetworkAgent);
+        ncb.setAccessUids(serviceUidSet);
+        mWiFiNetworkAgent.setNetworkCapabilities(ncb.build(), true /* sendToCS */);
+        cb.assertNoCallback(TEST_CALLBACK_TIMEOUT_MS);
+        mCm.unregisterNetworkCallback(cb);
     }
 
     /**
diff --git a/tests/unit/java/com/android/server/connectivity/CarrierPrivilegeAuthenticatorTest.java b/tests/unit/java/com/android/server/connectivity/CarrierPrivilegeAuthenticatorTest.java
index d193aa9..157507b 100644
--- a/tests/unit/java/com/android/server/connectivity/CarrierPrivilegeAuthenticatorTest.java
+++ b/tests/unit/java/com/android/server/connectivity/CarrierPrivilegeAuthenticatorTest.java
@@ -17,6 +17,7 @@
 package com.android.server.connectivity;
 
 import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
+import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
 import static android.telephony.TelephonyManager.ACTION_MULTI_SIM_CONFIG_CHANGED;
 
 import static com.android.testutils.DevSdkIgnoreRuleKt.SC_V2;
@@ -40,7 +41,9 @@
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.net.NetworkRequest;
+import android.net.NetworkSpecifier;
 import android.net.TelephonyNetworkSpecifier;
+import android.telephony.SubscriptionManager;
 import android.telephony.TelephonyManager;
 
 import com.android.networkstack.apishim.TelephonyManagerShimImpl;
@@ -66,27 +69,25 @@
 @RunWith(DevSdkIgnoreRunner.class)
 @IgnoreUpTo(SC_V2) // TODO: Use to Build.VERSION_CODES.SC_V2 when available
 public class CarrierPrivilegeAuthenticatorTest {
-    private static final String PACKAGE_NAME =
-            CarrierPrivilegeAuthenticatorTest.class.getPackage().getName();
-    private static final int TEST_SIM_SLOT_INDEX = 0;
-    private static final int TEST_SUBSCRIPTION_ID_1 = 2;
-    private static final int TEST_SUBSCRIPTION_ID_2 = 3;
+    private static final int SUBSCRIPTION_COUNT = 2;
+    private static final int TEST_SUBSCRIPTION_ID = 1;
 
     @NonNull private final Context mContext;
     @NonNull private final TelephonyManager mTelephonyManager;
     @NonNull private final TelephonyManagerShimImpl mTelephonyManagerShim;
     @NonNull private final PackageManager mPackageManager;
-    @NonNull private CarrierPrivilegeAuthenticatorChild mCarrierPrivilegeAuthenticator;
+    @NonNull private TestCarrierPrivilegeAuthenticator mCarrierPrivilegeAuthenticator;
     private final int mCarrierConfigPkgUid = 12345;
     private final String mTestPkg = "com.android.server.connectivity.test";
 
-    public class CarrierPrivilegeAuthenticatorChild extends CarrierPrivilegeAuthenticator {
-        CarrierPrivilegeAuthenticatorChild(@NonNull final Context c,
+    public class TestCarrierPrivilegeAuthenticator extends CarrierPrivilegeAuthenticator {
+        TestCarrierPrivilegeAuthenticator(@NonNull final Context c,
                 @NonNull final TelephonyManager t) {
             super(c, t, mTelephonyManagerShim);
         }
         @Override
         protected int getSlotIndex(int subId) {
+            if (SubscriptionManager.DEFAULT_SUBSCRIPTION_ID == subId) return TEST_SUBSCRIPTION_ID;
             return subId;
         }
     }
@@ -100,7 +101,7 @@
 
     @Before
     public void setUp() throws Exception {
-        doReturn(2).when(mTelephonyManager).getActiveModemCount();
+        doReturn(SUBSCRIPTION_COUNT).when(mTelephonyManager).getActiveModemCount();
         doReturn(mTestPkg).when(mTelephonyManagerShim)
                 .getCarrierServicePackageNameForLogicalSlot(anyInt());
         doReturn(mPackageManager).when(mContext).getPackageManager();
@@ -109,7 +110,7 @@
         doReturn(applicationInfo).when(mPackageManager)
                 .getApplicationInfo(eq(mTestPkg), anyInt());
         mCarrierPrivilegeAuthenticator =
-                new CarrierPrivilegeAuthenticatorChild(mContext, mTelephonyManager);
+                new TestCarrierPrivilegeAuthenticator(mContext, mTelephonyManager);
     }
 
     private IntentFilter getIntentFilter() {
@@ -126,7 +127,6 @@
             verify(mTelephonyManagerShim, atLeastOnce())
                     .addCarrierPrivilegesListener(anyInt(), any(), captor.capture());
         } catch (UnsupportedApiLevelException e) {
-
         }
         return captor.getAllValues();
     }
@@ -160,10 +160,10 @@
         networkRequestBuilder.addTransportType(TRANSPORT_CELLULAR);
         networkRequestBuilder.setNetworkSpecifier(telephonyNetworkSpecifier);
 
-        assertTrue(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkRequest(
-                mCarrierConfigPkgUid, networkRequestBuilder.build()));
-        assertFalse(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkRequest(
-                mCarrierConfigPkgUid + 1, networkRequestBuilder.build()));
+        assertTrue(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                mCarrierConfigPkgUid, networkRequestBuilder.build().networkCapabilities));
+        assertFalse(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                mCarrierConfigPkgUid + 1, networkRequestBuilder.build().networkCapabilities));
     }
 
     @Test
@@ -192,10 +192,10 @@
         final NetworkRequest.Builder networkRequestBuilder = new NetworkRequest.Builder();
         networkRequestBuilder.addTransportType(TRANSPORT_CELLULAR);
         networkRequestBuilder.setNetworkSpecifier(telephonyNetworkSpecifier);
-        assertTrue(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkRequest(
-                mCarrierConfigPkgUid, networkRequestBuilder.build()));
-        assertFalse(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkRequest(
-                mCarrierConfigPkgUid + 1, networkRequestBuilder.build()));
+        assertTrue(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                mCarrierConfigPkgUid, networkRequestBuilder.build().networkCapabilities));
+        assertFalse(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                mCarrierConfigPkgUid + 1, networkRequestBuilder.build().networkCapabilities));
     }
 
     @Test
@@ -215,9 +215,30 @@
                 .getApplicationInfo(eq(mTestPkg), anyInt());
         listener.onCarrierPrivilegesChanged(Collections.emptyList(), new int[] {});
 
-        assertFalse(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkRequest(
-                mCarrierConfigPkgUid, networkRequestBuilder.build()));
-        assertTrue(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkRequest(
-                mCarrierConfigPkgUid + 1, networkRequestBuilder.build()));
+        assertFalse(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                mCarrierConfigPkgUid, networkRequestBuilder.build().networkCapabilities));
+        assertTrue(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                mCarrierConfigPkgUid + 1, networkRequestBuilder.build().networkCapabilities));
+    }
+
+    @Test
+    public void testDefaultSubscription() throws Exception {
+        final NetworkRequest.Builder networkRequestBuilder = new NetworkRequest.Builder();
+        networkRequestBuilder.addTransportType(TRANSPORT_CELLULAR);
+        assertFalse(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                mCarrierConfigPkgUid, networkRequestBuilder.build().networkCapabilities));
+
+        networkRequestBuilder.setNetworkSpecifier(new TelephonyNetworkSpecifier(0));
+        assertTrue(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                mCarrierConfigPkgUid, networkRequestBuilder.build().networkCapabilities));
+
+        // The builder for NetworkRequest doesn't allow removing the transport as long as a
+        // specifier is set, so unset it first. TODO : fix the builder
+        networkRequestBuilder.setNetworkSpecifier((NetworkSpecifier) null);
+        networkRequestBuilder.removeTransportType(TRANSPORT_CELLULAR);
+        networkRequestBuilder.addTransportType(TRANSPORT_WIFI);
+        networkRequestBuilder.setNetworkSpecifier(new TelephonyNetworkSpecifier(0));
+        assertFalse(mCarrierPrivilegeAuthenticator.hasCarrierPrivilegeForNetworkCapabilities(
+                mCarrierConfigPkgUid, networkRequestBuilder.build().networkCapabilities));
     }
 }