Add reservationId to NetworkCapabilities

The reservationId is an internal field used for RESERVATION requests and
acts much like an internal, unique NetworkSpecifier value. A
NetworkRequest with a reservationId set can be satisfied by a Network /
Offer with the same reservationId or an Offer with the wildcard {@code
RES_ID_MATCH_ALL_RESERVATIONS}.

Regular requests do not set the reservationId and match any Network /
Offer (except the blanket offer) independent of their reservationId.

Test: NetworkCapabilitiesTest
Change-Id: Id06116adf776dbf09cb9f8ccb7f25ff51734e02e
diff --git a/framework/src/android/net/NetworkCapabilities.java b/framework/src/android/net/NetworkCapabilities.java
index 4a50397..c6b62ee 100644
--- a/framework/src/android/net/NetworkCapabilities.java
+++ b/framework/src/android/net/NetworkCapabilities.java
@@ -359,6 +359,7 @@
         mSubIds = new ArraySet<>();
         mUnderlyingNetworks = null;
         mEnterpriseId = 0;
+        mReservationId = RES_ID_UNSET;
     }
 
     /**
@@ -393,6 +394,7 @@
         // necessary.
         mUnderlyingNetworks = nc.mUnderlyingNetworks;
         mEnterpriseId = nc.mEnterpriseId;
+        mReservationId = nc.mReservationId;
     }
 
     /**
@@ -2233,7 +2235,8 @@
                 && (onlyImmutable || satisfiedByUids(nc))
                 && (onlyImmutable || satisfiedBySSID(nc))
                 && (onlyImmutable || satisfiedByRequestor(nc))
-                && (onlyImmutable || satisfiedBySubscriptionIds(nc)));
+                && (onlyImmutable || satisfiedBySubscriptionIds(nc)))
+                && satisfiedByReservationId(nc);
     }
 
     /**
@@ -2347,7 +2350,8 @@
                 && equalsAdministratorUids(that)
                 && equalsSubscriptionIds(that)
                 && equalsUnderlyingNetworks(that)
-                && equalsEnterpriseCapabilitiesId(that);
+                && equalsEnterpriseCapabilitiesId(that)
+                && equalsReservationId(that);
     }
 
     @Override
@@ -2373,7 +2377,9 @@
                 + Arrays.hashCode(mAdministratorUids) * 67
                 + Objects.hashCode(mSubIds) * 71
                 + Objects.hashCode(mUnderlyingNetworks) * 73
-                + mEnterpriseId * 79;
+                + mEnterpriseId * 79
+                + mReservationId * 83;
+
     }
 
     @Override
@@ -2411,6 +2417,7 @@
         dest.writeIntArray(CollectionUtils.toIntArray(mSubIds));
         dest.writeTypedList(mUnderlyingNetworks);
         dest.writeInt(mEnterpriseId & ALL_VALID_ENTERPRISE_IDS);
+        dest.writeInt(mReservationId);
     }
 
     public static final @android.annotation.NonNull Creator<NetworkCapabilities> CREATOR =
@@ -2446,6 +2453,7 @@
                 }
                 netCap.setUnderlyingNetworks(in.createTypedArrayList(Network.CREATOR));
                 netCap.mEnterpriseId = in.readInt() & ALL_VALID_ENTERPRISE_IDS;
+                netCap.mReservationId = in.readInt();
                 return netCap;
             }
             @Override
@@ -2548,6 +2556,11 @@
                     NetworkCapabilities::enterpriseIdNameOf, "&");
         }
 
+        if (mReservationId != RES_ID_UNSET) {
+            final boolean isReservationOffer = (mReservationId == RES_ID_MATCH_ALL_RESERVATIONS);
+            sb.append(" ReservationId: ").append(isReservationOffer ? "*" : mReservationId);
+        }
+
         sb.append(" UnderlyingNetworks: ");
         if (mUnderlyingNetworks != null) {
             sb.append("[");
@@ -2876,6 +2889,65 @@
     }
 
     /**
+     * The reservation ID used by non-reservable Networks and "regular" NetworkOffers.
+     *
+     * Note that {@code NetworkRequest#FIRST_REQUEST_ID} is 1;
+     * @hide
+     */
+    public static final int RES_ID_UNSET = 0;
+
+    /**
+     * The reservation ID used by special NetworkOffers that handle RESERVATION requests.
+     *
+     * NetworkOffers with {@code RES_ID_MATCH_ALL_RESERVATIONS} *only* receive onNetworkNeeded()
+     * callbacks for {@code NetworkRequest.Type.RESERVATION}.
+     * @hide
+     */
+    public static final int RES_ID_MATCH_ALL_RESERVATIONS = -1;
+
+    /**
+     * Unique ID that identifies the network reservation.
+     */
+    private int mReservationId;
+
+    /**
+     * Returns the reservation ID
+     * @hide
+     */
+    public int getReservationId() {
+        return mReservationId;
+    }
+
+    /**
+     * Set the reservation ID
+     * @hide
+     */
+    public void setReservationId(int resId) {
+        mReservationId = resId;
+    }
+
+    private boolean equalsReservationId(@NonNull NetworkCapabilities nc) {
+        return mReservationId == nc.mReservationId;
+    }
+
+    private boolean satisfiedByReservationId(@NonNull NetworkCapabilities nc) {
+        if (mReservationId == RES_ID_UNSET) {
+            // To maintain regular NetworkRequest semantics, a request with a zero reservationId
+            // matches an offer or network with any reservationId except MATCH_ALL_RESERVATIONS.
+            return nc.mReservationId != RES_ID_MATCH_ALL_RESERVATIONS;
+        }
+        // A request with a non-zero reservationId matches only an offer or network with that exact
+        // reservationId (required to match the network that will eventually come up) or
+        // MATCH_ALL_RESERVATIONS (required to match the blanket reservation offer).
+        if (nc.mReservationId == RES_ID_MATCH_ALL_RESERVATIONS) {
+            return true;
+        }
+        return mReservationId == nc.mReservationId;
+    }
+
+
+
+    /**
      * Returns a bitmask of all the applicable redactions (based on the permissions held by the
      * receiving app) to be performed on this object.
      *
diff --git a/tests/common/java/android/net/NetworkCapabilitiesTest.java b/tests/common/java/android/net/NetworkCapabilitiesTest.java
index 0f0e2f1..d694637 100644
--- a/tests/common/java/android/net/NetworkCapabilitiesTest.java
+++ b/tests/common/java/android/net/NetworkCapabilitiesTest.java
@@ -382,6 +382,7 @@
             netCap.setAllowedUids(allowedUids);
             netCap.setSubscriptionIds(Set.of(TEST_SUBID1, TEST_SUBID2));
             netCap.setUids(uids);
+            netCap.setReservationId(42);
         }
 
         netCap.setOwnerUid(123);
@@ -1493,4 +1494,42 @@
         // nc1 and nc2 are the same since invalid capability is ignored
         assertEquals(nc1, nc2);
     }
+
+    @Test
+    public void testReservationIdMatching() {
+        final NetworkCapabilities requestNc = new NetworkCapabilities();
+        final NetworkCapabilities reservationNc = new NetworkCapabilities();
+        reservationNc.setReservationId(42);
+
+        final NetworkCapabilities reservedNetworkNc = new NetworkCapabilities(reservationNc);
+        final NetworkCapabilities otherNetworkNc = new NetworkCapabilities();
+        final NetworkCapabilities otherReservedNetworkNc = new NetworkCapabilities();
+        otherReservedNetworkNc.setReservationId(99);
+        final NetworkCapabilities offerNc = new NetworkCapabilities();
+        offerNc.setReservationId(NetworkCapabilities.RES_ID_MATCH_ALL_RESERVATIONS);
+
+        // A regular request can match any network or offer except one with MATCH_ALL_RESERVATIONS
+        assertTrue(requestNc.satisfiedByNetworkCapabilities(reservedNetworkNc));
+        assertTrue(requestNc.satisfiedByNetworkCapabilities(otherNetworkNc));
+        assertTrue(requestNc.satisfiedByNetworkCapabilities(otherReservedNetworkNc));
+        assertFalse(requestNc.satisfiedByNetworkCapabilities(offerNc));
+
+        // A reservation request can only match the reservedNetwork and the blanket offer.
+        assertTrue(reservationNc.satisfiedByNetworkCapabilities(reservedNetworkNc));
+        assertFalse(reservationNc.satisfiedByNetworkCapabilities(otherNetworkNc));
+        assertFalse(reservationNc.satisfiedByNetworkCapabilities(otherReservedNetworkNc));
+        assertTrue(reservationNc.satisfiedByNetworkCapabilities(offerNc));
+    }
+
+    @Test @IgnoreUpTo(SC_V2)
+    public void testReservationIdEquals() {
+        final NetworkCapabilities nc = new NetworkCapabilities();
+        nc.setReservationId(42);
+        final NetworkCapabilities other = new NetworkCapabilities(nc);
+
+        assertEquals(nc, other);
+
+        nc.setReservationId(43);
+        assertNotEquals(nc, other);
+    }
 }