1 files changed, 65 insertions, 0 deletions
diff --git a/android/net/dns/ResolvUtil.java b/android/net/dns/ResolvUtil.java
new file mode 100644
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+++ b/android/net/dns/ResolvUtil.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.dns;
+
+import android.net.Network;
+import android.net.NetworkUtils;
+import android.system.GaiException;
+import android.system.OsConstants;
+import android.system.StructAddrinfo;
+
+import libcore.io.Libcore;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+
+/**
+ * DNS resolution utility class.
+ *
+ * @hide
+ */
+public class ResolvUtil {
+    // Non-portable DNS resolution flag.
+    private static final long NETID_USE_LOCAL_NAMESERVERS = 0x80000000L;
+
+    private ResolvUtil() {}
+
+    public static InetAddress[] blockingResolveAllLocally(Network network, String name)
+            throws UnknownHostException {
+        final StructAddrinfo hints = new StructAddrinfo();
+        // Unnecessary, but expressly no AI_ADDRCONFIG.
+        hints.ai_flags = 0;
+        // Fetch all IP addresses at once to minimize re-resolution.
+        hints.ai_family = OsConstants.AF_UNSPEC;
+        hints.ai_socktype = OsConstants.SOCK_DGRAM;
+
+        final Network networkForResolv = getNetworkWithUseLocalNameserversFlag(network);
+
+        try {
+            return Libcore.os.android_getaddrinfo(name, hints, (int) networkForResolv.netId);
+        } catch (GaiException gai) {
+            gai.rethrowAsUnknownHostException(name + ": TLS-bypass resolution failed");
+            return null;  // keep compiler quiet
+        }
+    }
+
+    public static Network getNetworkWithUseLocalNameserversFlag(Network network) {
+        final long netidForResolv = NETID_USE_LOCAL_NAMESERVERS | (long) network.netId;
+        return new Network((int) netidForResolv);
+    }
+}