Moved WifiWatchdogService and DnsPinger
- Moved WWS and DnsPinger in prep for StateMachine rewrite
intent.
Change-Id: I912ca80d31ee2ded99eb345a2e5a55d01bd9910c
diff --git a/core/java/android/net/DnsPinger.java b/core/java/android/net/DnsPinger.java
new file mode 100644
index 0000000..f2d84eb
--- /dev/null
+++ b/core/java/android/net/DnsPinger.java
@@ -0,0 +1,228 @@
+/*
+ * Copyright (C) 2011 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;
+
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.net.LinkProperties;
+import android.net.NetworkUtils;
+import android.os.SystemClock;
+import android.provider.Settings;
+import android.util.Slog;
+
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketTimeoutException;
+import java.util.Collection;
+import java.util.Random;
+
+/**
+ * Performs a simple DNS "ping" by sending a "server status" query packet to the
+ * DNS server. As long as the server replies, we consider it a success.
+ * <p>
+ * We do not use a simple hostname lookup because that could be cached and the
+ * API may not differentiate between a time out and a failure lookup (which we
+ * really care about).
+ * <p>
+ * TODO : More general API. Socket does not bind to specified connection type
+ * TODO : Choice of DNS query location - current looks up www.android.com
+ *
+ * @hide
+ */
+public final class DnsPinger {
+ private static final boolean V = true;
+
+ /** Number of bytes for the query */
+ private static final int DNS_QUERY_BASE_SIZE = 32;
+
+ /** The DNS port */
+ private static final int DNS_PORT = 53;
+
+ /** Used to generate IDs */
+ private static Random sRandom = new Random();
+
+ private ConnectivityManager mConnectivityManager = null;
+ private Context mContext;
+ private int mConnectionType;
+ private InetAddress mDefaultDns;
+
+ private String TAG;
+
+ /**
+ * @param connectionType The connection type from {@link ConnectivityManager}
+ */
+ public DnsPinger(String TAG, Context context, int connectionType) {
+ mContext = context;
+ mConnectionType = connectionType;
+ if (!ConnectivityManager.isNetworkTypeValid(connectionType)) {
+ Slog.e(TAG, "Invalid connectionType in constructor: " + connectionType);
+ }
+ this.TAG = TAG;
+
+ mDefaultDns = getDefaultDns();
+ }
+
+ /**
+ * @return The first DNS in the link properties of the specified connection
+ * type or the default system DNS if the link properties has null
+ * dns set. Should not be null.
+ */
+ public InetAddress getDns() {
+ LinkProperties curLinkProps = getCurrentLinkProperties();
+ if (curLinkProps == null) {
+ Slog.e(TAG, "getCurLinkProperties:: LP for type" + mConnectionType + " is null!");
+ return mDefaultDns;
+ }
+
+ Collection<InetAddress> dnses = curLinkProps.getDnses();
+ if (dnses == null || dnses.size() == 0) {
+ Slog.v(TAG, "getDns::LinkProps has null dns - returning default");
+ return mDefaultDns;
+ }
+
+ return dnses.iterator().next();
+ }
+
+ private LinkProperties getCurrentLinkProperties() {
+ if (mConnectivityManager == null) {
+ mConnectivityManager = (ConnectivityManager) mContext.getSystemService(
+ Context.CONNECTIVITY_SERVICE);
+ }
+
+ return mConnectivityManager.getLinkProperties(mConnectionType);
+ }
+
+ private InetAddress getDefaultDns() {
+ String dns = Settings.Secure.getString(mContext.getContentResolver(),
+ Settings.Secure.DEFAULT_DNS_SERVER);
+ if (dns == null || dns.length() == 0) {
+ dns = mContext.getResources().getString(
+ com.android.internal.R.string.config_default_dns_server);
+ }
+ try {
+ return NetworkUtils.numericToInetAddress(dns);
+ } catch (IllegalArgumentException e) {
+ Slog.w(TAG, "getDefaultDns::malformed default dns address");
+ return null;
+ }
+ }
+
+ /**
+ * @return time to response. Negative value on error.
+ */
+ public long pingDns(InetAddress dnsAddress, int timeout) {
+ DatagramSocket socket = null;
+ try {
+ socket = new DatagramSocket();
+
+ // Set some socket properties
+ socket.setSoTimeout(timeout);
+
+ // Try to bind but continue ping if bind fails
+ try {
+ socket.setNetworkInterface(NetworkInterface.getByName(
+ getCurrentLinkProperties().getInterfaceName()));
+ } catch (Exception e) {
+ Slog.d(TAG,"pingDns::Error binding to socket", e);
+ }
+
+ byte[] buf = constructQuery();
+
+ // Send the DNS query
+
+ DatagramPacket packet = new DatagramPacket(buf,
+ buf.length, dnsAddress, DNS_PORT);
+ long start = SystemClock.elapsedRealtime();
+ socket.send(packet);
+
+ // Wait for reply (blocks for the above timeout)
+ DatagramPacket replyPacket = new DatagramPacket(buf, buf.length);
+ socket.receive(replyPacket);
+
+ // If a timeout occurred, an exception would have been thrown. We
+ // got a reply!
+ return SystemClock.elapsedRealtime() - start;
+
+ } catch (SocketTimeoutException e) {
+ // Squelch this exception.
+ return -1;
+ } catch (Exception e) {
+ if (V) {
+ Slog.v(TAG, "DnsPinger.pingDns got socket exception: ", e);
+ }
+ return -2;
+ } finally {
+ if (socket != null) {
+ socket.close();
+ }
+ }
+
+ }
+
+ /**
+ * @return google.com DNS query packet
+ */
+ private static byte[] constructQuery() {
+ byte[] buf = new byte[DNS_QUERY_BASE_SIZE];
+
+ // [0-1] bytes are an ID, generate random ID for this query
+ buf[0] = (byte) sRandom.nextInt(256);
+ buf[1] = (byte) sRandom.nextInt(256);
+
+ // [2-3] bytes are for flags.
+ buf[2] = 0x01; // Recursion desired
+
+ // [4-5] bytes are for number of queries (QCOUNT)
+ buf[5] = 0x01;
+
+ // [6-7] [8-9] [10-11] are all counts of other fields we don't use
+
+ // [12-15] for www
+ writeString(buf, 12, "www");
+
+ // [16-22] for google
+ writeString(buf, 16, "google");
+
+ // [23-26] for com
+ writeString(buf, 23, "com");
+
+ // [27] is a null byte terminator byte for the url
+
+ // [28-29] bytes are for QTYPE, set to 1 = A (host address)
+ buf[29] = 0x01;
+
+ // [30-31] bytes are for QCLASS, set to 1 = IN (internet)
+ buf[31] = 0x01;
+
+ return buf;
+ }
+
+ /**
+ * Writes the string's length and its contents to the buffer
+ */
+ private static void writeString(byte[] buf, int startPos, String string) {
+ int pos = startPos;
+
+ // Write the length first
+ buf[pos++] = (byte) string.length();
+ for (int i = 0; i < string.length(); i++) {
+ buf[pos++] = (byte) string.charAt(i);
+ }
+ }
+}