Push DNS configuration on network validation

Test: as follows
    - built, flashed, booted
    - runtest frameworks-net passes
    - connected to captive portal network,
      saw failed validation attempt (opportunistic),
      passed portal, saw successful revalidation attempt
Bug: 64133961
Bug: 72344805
Bug: 109928338
Merged-In: Ic2046e053faf58e2edf2824e01145c61a9f2991f
Merged-In: I209c38fab7f05909e61731a348b1b1a2b35feab2
Change-Id: I0471685c2234af8a8c7f5b2ad3205eb6e36333c5
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 18b695f..6ef1c14 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -2254,6 +2254,7 @@
                         updateCapabilities(oldScore, nai, nai.networkCapabilities);
                         // If score has changed, rebroadcast to NetworkFactories. b/17726566
                         if (oldScore != nai.getCurrentScore()) sendUpdatedScoreToFactories(nai);
+                        if (valid) handleFreshlyValidatedNetwork(nai);
                     }
                     updateInetCondition(nai);
                     // Let the NetworkAgent know the state of its network
@@ -2348,6 +2349,16 @@
                 mDefaultRequest.networkCapabilities, nai.networkCapabilities);
     }
 
+    private void handleFreshlyValidatedNetwork(NetworkAgentInfo nai) {
+        if (nai == null) return;
+        // If the Private DNS mode is opportunistic, reprogram the DNS servers
+        // in order to restart a validation pass from within netd.
+        final PrivateDnsConfig cfg = mDnsManager.getPrivateDnsConfig();
+        if (cfg.useTls && TextUtils.isEmpty(cfg.hostname)) {
+            updateDnses(nai.linkProperties, null, nai.network.netId);
+        }
+    }
+
     private void handlePrivateDnsSettingsChanged() {
         final PrivateDnsConfig cfg = mDnsManager.getPrivateDnsConfig();