[VCN04] Add Subscription Id set into NetworkCapabilities

This is a generic way to request networks that has different
subId but belongs to the same carrier. For example, cellular
networks with different SIM card, or carrier Wifi that
provided by the operator.

Test: atest NetworkCapabilitiesTest#testSubIds
Test: m doc-comment-check-docs -j
Test: atest CtsNetTestCases
Bug: 175662146

Change-Id: Ifca766f5acc73c285948d6251ec31506d9bb0bcb
diff --git a/framework/src/android/net/NetworkCapabilities.java b/framework/src/android/net/NetworkCapabilities.java
index c82cd3b..73fbd61 100644
--- a/framework/src/android/net/NetworkCapabilities.java
+++ b/framework/src/android/net/NetworkCapabilities.java
@@ -131,6 +131,7 @@
         mPrivateDnsBroken = false;
         mRequestorUid = Process.INVALID_UID;
         mRequestorPackageName = null;
+        mSubIds = new ArraySet<>();
     }
 
     /**
@@ -159,6 +160,7 @@
         mPrivateDnsBroken = nc.mPrivateDnsBroken;
         mRequestorUid = nc.mRequestorUid;
         mRequestorPackageName = nc.mRequestorPackageName;
+        mSubIds = new ArraySet<>(nc.mSubIds);
     }
 
     /**
@@ -1655,6 +1657,7 @@
         combineSSIDs(nc);
         combineRequestor(nc);
         combineAdministratorUids(nc);
+        combineSubIds(nc);
     }
 
     /**
@@ -1674,8 +1677,9 @@
                 && satisfiedBySpecifier(nc)
                 && (onlyImmutable || satisfiedBySignalStrength(nc))
                 && (onlyImmutable || satisfiedByUids(nc))
-                && (onlyImmutable || satisfiedBySSID(nc)))
-                && (onlyImmutable || satisfiedByRequestor(nc));
+                && (onlyImmutable || satisfiedBySSID(nc))
+                && (onlyImmutable || satisfiedByRequestor(nc))
+                && (onlyImmutable || satisfiedBySubIds(nc)));
     }
 
     /**
@@ -1771,7 +1775,8 @@
                 && equalsOwnerUid(that)
                 && equalsPrivateDnsBroken(that)
                 && equalsRequestor(that)
-                && equalsAdministratorUids(that);
+                && equalsAdministratorUids(that)
+                && equalsSubIds(that);
     }
 
     @Override
@@ -1793,7 +1798,8 @@
                 + Objects.hashCode(mPrivateDnsBroken) * 47
                 + Objects.hashCode(mRequestorUid) * 53
                 + Objects.hashCode(mRequestorPackageName) * 59
-                + Arrays.hashCode(mAdministratorUids) * 61;
+                + Arrays.hashCode(mAdministratorUids) * 61
+                + Objects.hashCode(mSubIds) * 67;
     }
 
     @Override
@@ -1827,6 +1833,7 @@
         dest.writeInt(mOwnerUid);
         dest.writeInt(mRequestorUid);
         dest.writeString(mRequestorPackageName);
+        dest.writeIntArray(CollectionUtils.toIntArray(mSubIds));
     }
 
     public static final @android.annotation.NonNull Creator<NetworkCapabilities> CREATOR =
@@ -1850,6 +1857,11 @@
                 netCap.mOwnerUid = in.readInt();
                 netCap.mRequestorUid = in.readInt();
                 netCap.mRequestorPackageName = in.readString();
+                netCap.mSubIds = new ArraySet<>();
+                final int[] subIdInts = Objects.requireNonNull(in.createIntArray());
+                for (int i = 0; i < subIdInts.length; i++) {
+                    netCap.mSubIds.add(subIdInts[i]);
+                }
                 return netCap;
             }
             @Override
@@ -1933,11 +1945,14 @@
             sb.append(" SSID: ").append(mSSID);
         }
 
-
         if (mPrivateDnsBroken) {
             sb.append(" PrivateDnsBroken");
         }
 
+        if (!mSubIds.isEmpty()) {
+            sb.append(" SubscriptionIds: ").append(mSubIds);
+        }
+
         sb.append("]");
         return sb.toString();
     }
@@ -2251,6 +2266,68 @@
     }
 
     /**
+     * Set of the subscription IDs that identifies the network or request, empty if none.
+     */
+    @NonNull
+    private ArraySet<Integer> mSubIds = new ArraySet<>();
+
+    /**
+     * Sets the subscription ID set that associated to this network or request.
+     *
+     * @hide
+     */
+    @NonNull
+    public NetworkCapabilities setSubIds(@NonNull Set<Integer> subIds) {
+        mSubIds = new ArraySet(Objects.requireNonNull(subIds));
+        return this;
+    }
+
+    /**
+     * Gets the subscription ID set that associated to this network or request.
+     * @hide
+     * @return
+     */
+    @NonNull
+    public Set<Integer> getSubIds() {
+        return new ArraySet<>(mSubIds);
+    }
+
+    /**
+     * Tests if the subscription ID set of this network is the same as that of the passed one.
+     */
+    private boolean equalsSubIds(@NonNull NetworkCapabilities nc) {
+        return Objects.equals(mSubIds, nc.mSubIds);
+    }
+
+    /**
+     * Check if the subscription ID set requirements of this object are matched by the passed one.
+     * If specified in the request, the passed one need to have at least one subId and at least
+     * one of them needs to be in the request set.
+     */
+    private boolean satisfiedBySubIds(@NonNull NetworkCapabilities nc) {
+        if (mSubIds.isEmpty()) return true;
+        if (nc.mSubIds.isEmpty()) return false;
+        for (final Integer subId : nc.mSubIds) {
+            if (mSubIds.contains(subId)) return true;
+        }
+        return false;
+    }
+
+    /**
+     * Combine subscription ID set of the capabilities.
+     *
+     * <p>This is only legal if the subscription Ids are equal.
+     *
+     * <p>If both subscription IDs are not equal, they belong to different subscription
+     * (or no subscription). In this case, it would not make sense to add them together.
+     */
+    private void combineSubIds(@NonNull NetworkCapabilities nc) {
+        if (!Objects.equals(mSubIds, nc.mSubIds)) {
+            throw new IllegalStateException("Can't combine two subscription ID sets");
+        }
+    }
+
+    /**
      * Builder class for NetworkCapabilities.
      *
      * This class is mainly for for {@link NetworkAgent} instances to use. Many fields in
@@ -2556,6 +2633,20 @@
         }
 
         /**
+         * Set the subscription ID set.
+         *
+         * @param subIds a set that represent the subscription IDs. Empty if clean up.
+         * @return this builder.
+         *
+         * @hide
+         */
+        @NonNull
+        public Builder setSubIds(@NonNull final Set<Integer> subIds) {
+            mCaps.setSubIds(subIds);
+            return this;
+        }
+
+        /**
          * Builds the instance of the capabilities.
          *
          * @return the built instance of NetworkCapabilities.
diff --git a/framework/src/android/net/NetworkRequest.java b/framework/src/android/net/NetworkRequest.java
index 17a8ee1..65ca1b2 100644
--- a/framework/src/android/net/NetworkRequest.java
+++ b/framework/src/android/net/NetworkRequest.java
@@ -456,6 +456,23 @@
             }
             nc.addCapability(NET_CAPABILITY_NOT_VCN_MANAGED);
         }
+
+        /**
+         * Sets the optional subscription ID set.
+         * <p>
+         * This specify the subscription IDs requirement.
+         * A network will satisfy this request only if it matches one of the subIds in this set.
+         * An empty set matches all networks, including those without a subId.
+         *
+         * @param subIds A {@code Set} that represents subscription IDs.
+         *
+         * @hide
+         */
+        @NonNull
+        public Builder setSubIds(@NonNull Set<Integer> subIds) {
+            mNetworkCapabilities.setSubIds(subIds);
+            return this;
+        }
     }
 
     // implement the Parcelable interface
diff --git a/tests/net/common/java/android/net/NetworkCapabilitiesTest.java b/tests/net/common/java/android/net/NetworkCapabilitiesTest.java
index e84b992..0dfec75 100644
--- a/tests/net/common/java/android/net/NetworkCapabilitiesTest.java
+++ b/tests/net/common/java/android/net/NetworkCapabilitiesTest.java
@@ -28,6 +28,7 @@
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_METERED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VCN_MANAGED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VPN;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_OEM_PAID;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_OEM_PRIVATE;
@@ -44,6 +45,10 @@
 import static android.net.NetworkCapabilities.UNRESTRICTED_CAPABILITIES;
 import static android.os.Process.INVALID_UID;
 
+import static com.android.modules.utils.build.SdkLevel.isAtLeastR;
+import static com.android.modules.utils.build.SdkLevel.isAtLeastS;
+import static com.android.testutils.MiscAsserts.assertEmpty;
+import static com.android.testutils.MiscAsserts.assertThrows;
 import static com.android.testutils.ParcelUtils.assertParcelSane;
 import static com.android.testutils.ParcelUtils.assertParcelingIsLossless;
 import static com.android.testutils.ParcelUtils.parcelingRoundTrip;
@@ -67,7 +72,6 @@
 
 import androidx.test.runner.AndroidJUnit4;
 
-import com.android.modules.utils.build.SdkLevel;
 import com.android.testutils.CompatUtil;
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
@@ -85,6 +89,9 @@
 public class NetworkCapabilitiesTest {
     private static final String TEST_SSID = "TEST_SSID";
     private static final String DIFFERENT_TEST_SSID = "DIFFERENT_TEST_SSID";
+    private static final int TEST_SUBID1 = 1;
+    private static final int TEST_SUBID2 = 2;
+    private static final int TEST_SUBID3 = 3;
 
     @Rule
     public DevSdkIgnoreRule mDevSdkIgnoreRule = new DevSdkIgnoreRule();
@@ -92,14 +99,6 @@
     private DiscoverySession mDiscoverySession = Mockito.mock(DiscoverySession.class);
     private PeerHandle mPeerHandle = Mockito.mock(PeerHandle.class);
 
-    private boolean isAtLeastR() {
-        return SdkLevel.isAtLeastR();
-    }
-
-    private boolean isAtLeastS() {
-        return SdkLevel.isAtLeastS();
-    }
-
     @Test
     public void testMaybeMarkCapabilitiesRestricted() {
         // verify EIMS is restricted
@@ -305,7 +304,9 @@
             .setUids(uids)
             .addCapability(NET_CAPABILITY_EIMS)
             .addCapability(NET_CAPABILITY_NOT_METERED);
-        if (isAtLeastR()) {
+        if (isAtLeastS()) {
+            netCap.setSubIds(Set.of(TEST_SUBID1, TEST_SUBID2));
+        } else if (isAtLeastR()) {
             netCap.setOwnerUid(123);
             netCap.setAdministratorUids(new int[] {5, 11});
         }
@@ -380,7 +381,7 @@
 
     private void testParcelSane(NetworkCapabilities cap) {
         if (isAtLeastS()) {
-            assertParcelSane(cap, 16);
+            assertParcelSane(cap, 17);
         } else if (isAtLeastR()) {
             assertParcelSane(cap, 15);
         } else {
@@ -614,6 +615,20 @@
         assertFalse(nc2.appliesToUid(12));
         assertTrue(nc1.appliesToUid(22));
         assertTrue(nc2.appliesToUid(22));
+
+        // Verify the subscription id list can be combined only when they are equal.
+        if (isAtLeastS()) {
+            nc1.setSubIds(Set.of(TEST_SUBID1, TEST_SUBID2));
+            nc2.setSubIds(Set.of(TEST_SUBID2));
+            assertThrows(IllegalStateException.class, () -> nc2.combineCapabilities(nc1));
+
+            nc2.setSubIds(Set.of());
+            assertThrows(IllegalStateException.class, () -> nc2.combineCapabilities(nc1));
+
+            nc2.setSubIds(Set.of(TEST_SUBID2, TEST_SUBID1));
+            nc2.combineCapabilities(nc1);
+            assertEquals(Set.of(TEST_SUBID2, TEST_SUBID1), nc2.getSubIds());
+        }
     }
 
     @Test @IgnoreUpTo(Build.VERSION_CODES.Q)
@@ -762,6 +777,24 @@
         nc1.setUids(uidRange(10, 13));
         nc2.set(nc1);  // Overwrites, as opposed to combineCapabilities
         assertEquals(nc1, nc2);
+
+        if (isAtLeastS()) {
+            assertThrows(NullPointerException.class, () -> nc1.setSubIds(null));
+            nc1.setSubIds(Set.of());
+            nc2.set(nc1);
+            assertEquals(nc1, nc2);
+
+            nc1.setSubIds(Set.of(TEST_SUBID1));
+            nc2.set(nc1);
+            assertEquals(nc1, nc2);
+
+            nc2.setSubIds(Set.of(TEST_SUBID2, TEST_SUBID1));
+            nc2.set(nc1);
+            assertEquals(nc1, nc2);
+
+            nc2.setSubIds(Set.of(TEST_SUBID3, TEST_SUBID2));
+            assertNotEquals(nc1, nc2);
+        }
     }
 
     @Test
@@ -842,6 +875,50 @@
         } catch (NullPointerException expected) { }
     }
 
+    private static NetworkCapabilities capsWithSubIds(Integer ... subIds) {
+        // Since the NetworkRequest would put NOT_VCN_MANAGED capabilities in general, for
+        // every NetworkCapabilities that simulates networks needs to add it too in order to
+        // satisfy these requests.
+        final NetworkCapabilities nc = new NetworkCapabilities.Builder()
+                .addCapability(NET_CAPABILITY_NOT_VCN_MANAGED)
+                .setSubIds(new ArraySet<>(subIds)).build();
+        assertEquals(new ArraySet<>(subIds), nc.getSubIds());
+        return nc;
+    }
+
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
+    public void testSubIds() throws Exception {
+        final NetworkCapabilities ncWithoutId = capsWithSubIds();
+        final NetworkCapabilities ncWithId = capsWithSubIds(TEST_SUBID1);
+        final NetworkCapabilities ncWithOtherIds = capsWithSubIds(TEST_SUBID1, TEST_SUBID3);
+        final NetworkCapabilities ncWithoutRequestedIds = capsWithSubIds(TEST_SUBID3);
+
+        final NetworkRequest requestWithoutId = new NetworkRequest.Builder().build();
+        assertEmpty(requestWithoutId.networkCapabilities.getSubIds());
+        final NetworkRequest requestWithIds = new NetworkRequest.Builder()
+                .setSubIds(Set.of(TEST_SUBID1, TEST_SUBID2)).build();
+        assertEquals(Set.of(TEST_SUBID1, TEST_SUBID2),
+                requestWithIds.networkCapabilities.getSubIds());
+
+        assertFalse(requestWithIds.canBeSatisfiedBy(ncWithoutId));
+        assertTrue(requestWithIds.canBeSatisfiedBy(ncWithOtherIds));
+        assertFalse(requestWithIds.canBeSatisfiedBy(ncWithoutRequestedIds));
+        assertTrue(requestWithIds.canBeSatisfiedBy(ncWithId));
+        assertTrue(requestWithoutId.canBeSatisfiedBy(ncWithoutId));
+        assertTrue(requestWithoutId.canBeSatisfiedBy(ncWithId));
+    }
+
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
+    public void testEqualsSubIds() throws Exception {
+        assertEquals(capsWithSubIds(), capsWithSubIds());
+        assertNotEquals(capsWithSubIds(), capsWithSubIds(TEST_SUBID1));
+        assertEquals(capsWithSubIds(TEST_SUBID1), capsWithSubIds(TEST_SUBID1));
+        assertNotEquals(capsWithSubIds(TEST_SUBID1), capsWithSubIds(TEST_SUBID2));
+        assertNotEquals(capsWithSubIds(TEST_SUBID1), capsWithSubIds(TEST_SUBID2, TEST_SUBID1));
+        assertEquals(capsWithSubIds(TEST_SUBID1, TEST_SUBID2),
+                capsWithSubIds(TEST_SUBID2, TEST_SUBID1));
+    }
+
     @Test
     public void testLinkBandwidthKbps() {
         final NetworkCapabilities nc = new NetworkCapabilities();
@@ -1022,5 +1099,11 @@
             fail("Should not set null into NetworkCapabilities.Builder");
         } catch (NullPointerException expected) { }
         assertEquals(nc, new NetworkCapabilities.Builder(nc).build());
+
+        if (isAtLeastS()) {
+            final NetworkCapabilities nc2 = new NetworkCapabilities.Builder()
+                    .setSubIds(Set.of(TEST_SUBID1)).build();
+            assertEquals(Set.of(TEST_SUBID1), nc2.getSubIds());
+        }
     }
 }