From d5cca3b3a48cfaed3008050fcab9574d97d771cc Mon Sep 17 00:00:00 2001 From: Rene Treffer Date: Wed, 2 Apr 2014 22:45:57 +0200 Subject: Try various ways to get the dns settings --- src/de/measite/minidns/Client.java | 91 +++++++++++++++++++++++++++++++++++++- 1 file changed, 90 insertions(+), 1 deletion(-) (limited to 'src') diff --git a/src/de/measite/minidns/Client.java b/src/de/measite/minidns/Client.java index c32ec3a1..beb461be 100644 --- a/src/de/measite/minidns/Client.java +++ b/src/de/measite/minidns/Client.java @@ -4,14 +4,18 @@ import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.LineNumberReader; +import java.lang.reflect.Method; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; +import java.util.ArrayList; +import java.util.Arrays; import java.util.HashSet; import java.util.Random; +import android.util.Log; import de.measite.minidns.Record.CLASS; import de.measite.minidns.Record.TYPE; @@ -130,6 +134,33 @@ public class Client { * @return The server array. */ public String[] findDNS() { + String[] result = findDNSByReflection(); + if (result != null) { + Log.d("minidns/client", + "Got DNS servers via reflection: " + Arrays.toString(result)); + return result; + } + + result = findDNSByExec(); + if (result != null) { + Log.d("minidns/client", + "Got DNS servers via exec: " + Arrays.toString(result)); + return result; + } + + // fallback for ipv4 and ipv6 connectivity + // see https://developers.google.com/speed/public-dns/docs/using + Log.d("minidns/client", + "No DNS found? Using fallback [8.8.8.8, [2001:4860:4860::8888]]"); + + return new String[]{"8.8.8.8", "[2001:4860:4860::8888]"}; + } + + /** + * Try to retrieve the list of dns server by executing getprop. + * @return Array of servers, or null on failure. + */ + protected String[] findDNSByExec() { try { Process process = Runtime.getRuntime().exec("getprop"); InputStream inputStream = process.getInputStream(); @@ -146,7 +177,19 @@ public class Client { String value = line.substring(split + 4, line.length() - 1); if (property.endsWith(".dns") || property.endsWith(".dns1") || property.endsWith(".dns2") || property.endsWith(".dns3") || - property.endsWith(".dns4")) { + property.endsWith(".dns4")) { + + // normalize the address + + InetAddress ip = InetAddress.getByName(value); + + if (ip == null) continue; + + value = ip.getHostAddress(); + + if (value == null) continue; + if (value.length() == 0) continue; + server.add(value); } } @@ -158,4 +201,50 @@ public class Client { } return null; } + + /** + * Try to retrieve the list of dns server by calling SystemProperties. + * @return Array of servers, or null on failure. + */ + protected String[] findDNSByReflection() { + try { + Class SystemProperties = + Class.forName("android.os.SystemProperties"); + Method method = SystemProperties.getMethod("get", + new Class[] { String.class }); + + ArrayList servers = new ArrayList(5); + + for (String propKey : new String[] { + "net.dns1", "net.dns2", "net.dns3", "net.dns4"}) { + + String value = (String)method.invoke(null, propKey); + + if (value == null) continue; + if (value.length() == 0) continue; + if (servers.contains(value)) continue; + + InetAddress ip = InetAddress.getByName(value); + + if (ip == null) continue; + + value = ip.getHostAddress(); + + if (value == null) continue; + if (value.length() == 0) continue; + if (servers.contains(value)) continue; + + servers.add(value); + } + + if (servers.size() > 0) { + return servers.toArray(new String[servers.size()]); + } + } catch (Exception e) { + // we might trigger some problems this way + e.printStackTrace(); + } + return null; + } + } -- cgit v1.2.3