diff options
| -rw-r--r-- | services/java/com/android/server/DnsPinger.java | 78 |
1 files changed, 44 insertions, 34 deletions
diff --git a/services/java/com/android/server/DnsPinger.java b/services/java/com/android/server/DnsPinger.java index a7324d9a958d..4e33938b2ca8 100644 --- a/services/java/com/android/server/DnsPinger.java +++ b/services/java/com/android/server/DnsPinger.java @@ -16,7 +16,6 @@ package com.android.server; -import android.content.ContentResolver; import android.content.Context; import android.net.ConnectivityManager; import android.net.LinkProperties; @@ -28,6 +27,7 @@ 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; @@ -49,7 +49,7 @@ public final class DnsPinger { private static final boolean V = true; /** Number of bytes for the query */ - private static final int DNS_QUERY_BASE_SIZE = 33; + private static final int DNS_QUERY_BASE_SIZE = 32; /** The DNS port */ private static final int DNS_PORT = 53; @@ -84,12 +84,7 @@ public final class DnsPinger { * dns set. Should not be null. */ public InetAddress getDns() { - if (mConnectivityManager == null) { - mConnectivityManager = (ConnectivityManager) mContext.getSystemService( - Context.CONNECTIVITY_SERVICE); - } - - LinkProperties curLinkProps = mConnectivityManager.getLinkProperties(mConnectionType); + LinkProperties curLinkProps = getCurrentLinkProperties(); if (curLinkProps == null) { Slog.e(TAG, "getCurLinkProperties:: LP for type" + mConnectionType + " is null!"); return mDefaultDns; @@ -104,6 +99,15 @@ public final class DnsPinger { 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); @@ -130,8 +134,15 @@ public final class DnsPinger { // Set some socket properties socket.setSoTimeout(timeout); - byte[] buf = new byte[DNS_QUERY_BASE_SIZE]; - fillQuery(buf); + // 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 @@ -164,48 +175,47 @@ public final class DnsPinger { } - private static void fillQuery(byte[] buf) { - - /* - * See RFC2929 (though the bit tables in there are misleading for us. - * For example, the recursion desired bit is the 0th bit for us, but - * looking there it would appear as the 7th bit of the byte - */ - - // Make sure it's all zeroed out - for (int i = 0; i < buf.length; i++) - buf[i] = 0; - - // Form a query for www.android.com + /** + * @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] = 1; // Recursion desired + buf[2] = 0x01; // Recursion desired - // [4-5] bytes are for the query count - buf[5] = 1; // One query + // [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"); - // [16-23] for android - writeString(buf, 16, "android"); + // [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 - // [24-27] for com - writeString(buf, 24, "com"); + // [28-29] bytes are for QTYPE, set to 1 = A (host address) + buf[29] = 0x01; - // [29-30] bytes are for QTYPE, set to 1 - buf[30] = 1; + // [30-31] bytes are for QCLASS, set to 1 = IN (internet) + buf[31] = 0x01; - // [31-32] bytes are for QCLASS, set to 1 - buf[32] = 1; + 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; |