Allow use of bindProcessToNetwork only to change private DNS bypass.

Currently it is not possible to change private DNS bypass by
doing:

  setProcessDefaultNetwork(network.getPrivateDnsBypassingCopy());
  setProcessDefaultNetwork(network);

because the code will ignore the change. Fix this by ensuring
that we always call bindProcessToNetwork (which does not have
side effects) and then only performing the expensive operations
(flushing DNS cache, upating socket pools) if the netId changed.

Bug: 112869080
Test: None
Change-Id: I5e8999cb11d8b8c1e9eb583fa8b3932f212accff

1 files changed, 10 insertions, 7 deletions

diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 41a32a1df902..160157771b18 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -3970,13 +3970,17 @@ public class ConnectivityManager {
     @Deprecated
     public static boolean setProcessDefaultNetwork(@Nullable Network network) {
         int netId = (network == null) ? NETID_UNSET : network.netId;
-        if (netId == NetworkUtils.getBoundNetworkForProcess()) {
-            return true;
-        }
+        boolean isSameNetId = (netId == NetworkUtils.getBoundNetworkForProcess());
+
         if (netId != NETID_UNSET) {
             netId = network.getNetIdForResolv();
         }
-        if (NetworkUtils.bindProcessToNetwork(netId)) {
+
+        if (!NetworkUtils.bindProcessToNetwork(netId)) {
+            return false;
+        }
+
+        if (!isSameNetId) {
             // Set HTTP proxy system properties to match network.
             // TODO: Deprecate this static method and replace it with a non-static version.
             try {
@@ -3990,10 +3994,9 @@ public class ConnectivityManager {
             // Must flush socket pool as idle sockets will be bound to previous network and may
             // cause subsequent fetches to be performed on old network.
             NetworkEventDispatcher.getInstance().onNetworkConfigurationChanged();
-            return true;
-        } else {
-            return false;
         }
+
+        return true;
     }
 
     /**