Fix a bug where private DNS to v4-only servers don't validate.

Bug: 132670008
Test: Manual
Test: atest NetworkStackTests
Change-Id: I8ae6fa6f3800f5f6c9ee88ffe3b8ada34b96dee6
Merged-In: I362d43ee6af318694a4038a257e1ebb3f577863c

1 files changed, 17 insertions, 6 deletions

diff --git a/src/com/android/networkstack/util/DnsUtils.java b/src/com/android/networkstack/util/DnsUtils.java
index 85f94e1..4767d55 100644
--- a/src/com/android/networkstack/util/DnsUtils.java
+++ b/src/com/android/networkstack/util/DnsUtils.java
@@ -55,12 +55,23 @@ public class DnsUtils {
             throws UnknownHostException {
         final List<InetAddress> result = new ArrayList<InetAddress>();
 
-        result.addAll(Arrays.asList(
-                getAllByName(dnsResolver, network, host, TYPE_AAAA, FLAG_NO_CACHE_LOOKUP,
-                timeout)));
-        result.addAll(Arrays.asList(
-                getAllByName(dnsResolver, network, host, TYPE_A, FLAG_NO_CACHE_LOOKUP,
-                timeout)));
+        try {
+            result.addAll(Arrays.asList(
+                    getAllByName(dnsResolver, network, host, TYPE_AAAA, FLAG_NO_CACHE_LOOKUP,
+                    timeout)));
+        } catch (UnknownHostException e) {
+            // Might happen if the host is v4-only, still need to query TYPE_A
+        }
+        try {
+            result.addAll(Arrays.asList(
+                    getAllByName(dnsResolver, network, host, TYPE_A, FLAG_NO_CACHE_LOOKUP,
+                    timeout)));
+        } catch (UnknownHostException e) {
+            // Might happen if the host is v6-only, still need to return AAAA answers
+        }
+        if (result.size() == 0) {
+            throw new UnknownHostException(host);
+        }
         return result.toArray(new InetAddress[0]);
     }