Stop using VPNs in getActiveNetworkForUidInternal.

After this CL, ConnectivityService no longer needs to grab the
VPN lock and access Vpn objects to determine connectivity state.

Also make a synchronized (mVpns) block smaller.

Bug: 173331190
Test: existing tests in ConnectivityServiceTest
Change-Id: I3297b3ab8e75bdf4902c62dd7e492c3634cfc51f
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 69f2457..d8dc933 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -28,7 +28,6 @@
 import static android.net.ConnectivityDiagnosticsManager.DataStallReport.KEY_TCP_METRICS_COLLECTION_PERIOD_MILLIS;
 import static android.net.ConnectivityDiagnosticsManager.DataStallReport.KEY_TCP_PACKET_FAIL_RATE;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
-import static android.net.ConnectivityManager.NETID_UNSET;
 import static android.net.ConnectivityManager.PRIVATE_DNS_MODE_OPPORTUNISTIC;
 import static android.net.ConnectivityManager.TYPE_ETHERNET;
 import static android.net.ConnectivityManager.TYPE_NONE;
@@ -1444,31 +1443,20 @@
     }
 
     private Network getActiveNetworkForUidInternal(final int uid, boolean ignoreBlocked) {
-        final int user = UserHandle.getUserId(uid);
-        int vpnNetId = NETID_UNSET;
-        synchronized (mVpns) {
-            final Vpn vpn = mVpns.get(user);
-            // TODO : now that capabilities contain the UID, the appliesToUid test should
-            // be removed as the satisfying test below should be enough.
-            if (vpn != null && vpn.appliesToUid(uid)) vpnNetId = vpn.getNetId();
-        }
-        NetworkAgentInfo nai;
-        if (vpnNetId != NETID_UNSET) {
-            nai = getNetworkAgentInfoForNetId(vpnNetId);
-            if (nai != null) {
-                final NetworkCapabilities requiredCaps =
-                    createDefaultNetworkCapabilitiesForUid(uid);
-                if (requiredCaps.satisfiedByNetworkCapabilities(nai.networkCapabilities)) {
-                    return nai.network;
-                }
+        final NetworkAgentInfo vpnNai = getVpnForUid(uid);
+        if (vpnNai != null) {
+            final NetworkCapabilities requiredCaps = createDefaultNetworkCapabilitiesForUid(uid);
+            if (requiredCaps.satisfiedByNetworkCapabilities(vpnNai.networkCapabilities)) {
+                return vpnNai.network;
             }
         }
-        nai = getDefaultNetwork();
-        if (nai != null && isNetworkWithCapabilitiesBlocked(
-                nai.networkCapabilities, uid, ignoreBlocked)) {
-            nai = null;
+
+        NetworkAgentInfo nai = getDefaultNetwork();
+        if (nai == null || isNetworkWithCapabilitiesBlocked(nai.networkCapabilities, uid,
+                ignoreBlocked)) {
+            return null;
         }
-        return nai != null ? nai.network : null;
+        return nai.network;
     }
 
     // Public because it's used by mLockdownTracker.
@@ -4814,15 +4802,15 @@
             if (mLockdownEnabled) {
                 return new VpnInfo[0];
             }
-            List<VpnInfo> infoList = new ArrayList<>();
-            for (NetworkAgentInfo nai : mNetworkAgentInfos) {
-                VpnInfo info = createVpnInfo(nai);
-                if (info != null) {
-                    infoList.add(info);
-                }
-            }
-            return infoList.toArray(new VpnInfo[infoList.size()]);
         }
+        List<VpnInfo> infoList = new ArrayList<>();
+        for (NetworkAgentInfo nai : mNetworkAgentInfos) {
+            VpnInfo info = createVpnInfo(nai);
+            if (info != null) {
+                infoList.add(info);
+            }
+        }
+        return infoList.toArray(new VpnInfo[infoList.size()]);
     }
 
     /**