upgrade minidns. refactored dns utils

6 files changed, 273 insertions, 324 deletions

diff --git a/src/main/java/de/pixart/messenger/services/XmppConnectionService.java b/src/main/java/de/pixart/messenger/services/XmppConnectionService.java
index d5ea710e5..243b9b4f5 100644
--- a/src/main/java/de/pixart/messenger/services/XmppConnectionService.java
+++ b/src/main/java/de/pixart/messenger/services/XmppConnectionService.java
@@ -120,6 +120,7 @@ import de.pixart.messenger.utils.OnPhoneContactsLoadedListener;
 import de.pixart.messenger.utils.PRNGFixes;
 import de.pixart.messenger.utils.PhoneHelper;
 import de.pixart.messenger.utils.ReplacingSerialSingleThreadExecutor;
+import de.pixart.messenger.utils.Resolver;
 import de.pixart.messenger.utils.SerialSingleThreadExecutor;
 import de.pixart.messenger.utils.XmppUri;
 import de.pixart.messenger.xml.Element;
@@ -1085,6 +1086,7 @@ public class XmppConnectionService extends Service {
     public void onCreate() {
         ExceptionHelper.init(getApplicationContext());
         PRNGFixes.apply();
+        Resolver.registerLookupMechanism(this);
         this.mRandom = new SecureRandom();
         updateMemorizingTrustmanager();
         final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
diff --git a/src/main/java/de/pixart/messenger/utils/AndroidUsingLinkProperties.java b/src/main/java/de/pixart/messenger/utils/AndroidUsingLinkProperties.java
new file mode 100644
index 000000000..b201b354b
--- /dev/null
+++ b/src/main/java/de/pixart/messenger/utils/AndroidUsingLinkProperties.java
@@ -0,0 +1,76 @@
+package de.pixart.messenger.utils;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.RouteInfo;
+import android.os.Build;
+
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.List;
+
+import de.measite.minidns.dnsserverlookup.AbstractDNSServerLookupMechanism;
+import de.measite.minidns.dnsserverlookup.AndroidUsingExec;
+
+public class AndroidUsingLinkProperties extends AbstractDNSServerLookupMechanism {
+
+    private final Context context;
+
+    protected AndroidUsingLinkProperties(Context context) {
+        super(AndroidUsingLinkProperties.class.getSimpleName(), AndroidUsingExec.PRIORITY - 1);
+        this.context = context;
+    }
+
+    @Override
+    public boolean isAvailable() {
+        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP;
+    }
+
+    @Override
+    @TargetApi(21)
+    public String[] getDnsServerAddresses() {
+        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
+        Network[] networks = connectivityManager == null ? null : connectivityManager.getAllNetworks();
+        if (networks == null) {
+            return new String[0];
+        }
+        List<String> servers = new ArrayList<>();
+        for (Network network : networks) {
+            LinkProperties linkProperties = connectivityManager.getLinkProperties(network);
+            if (linkProperties != null) {
+                if (hasDefaultRoute(linkProperties)) {
+                    servers.addAll(0, getIPv4First(linkProperties.getDnsServers()));
+                } else {
+                    servers.addAll(getIPv4First(linkProperties.getDnsServers()));
+                }
+            }
+        }
+        return servers.toArray(new String[servers.size()]);
+    }
+
+    private static List<String> getIPv4First(List<InetAddress> in) {
+        List<String> out = new ArrayList<>();
+        for (InetAddress addr : in) {
+            if (addr instanceof Inet4Address) {
+                out.add(0, addr.toString());
+            } else {
+                out.add(addr.toString());
+            }
+        }
+        return out;
+    }
+
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    private static boolean hasDefaultRoute(LinkProperties linkProperties) {
+        for (RouteInfo route : linkProperties.getRoutes()) {
+            if (route.isDefaultRoute()) {
+                return true;
+            }
+        }
+        return false;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/de/pixart/messenger/utils/DNSHelper.java b/src/main/java/de/pixart/messenger/utils/DNSHelper.java
deleted file mode 100644
index 70f600375..000000000
--- a/src/main/java/de/pixart/messenger/utils/DNSHelper.java
+++ /dev/null
@@ -1,299 +0,0 @@
-package de.pixart.messenger.utils;
-
-import android.annotation.TargetApi;
-import android.content.Context;
-import android.net.ConnectivityManager;
-import android.net.LinkProperties;
-import android.net.Network;
-import android.net.RouteInfo;
-import android.os.Build;
-import android.os.Bundle;
-import android.os.Parcelable;
-import android.util.Log;
-
-import java.io.IOException;
-import java.net.Inet4Address;
-import java.net.InetAddress;
-import java.net.SocketTimeoutException;
-import java.net.UnknownHostException;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import java.util.Locale;
-import java.util.Map;
-import java.util.Random;
-import java.util.TreeMap;
-import java.util.regex.Pattern;
-
-import de.measite.minidns.Client;
-import de.measite.minidns.DNSMessage;
-import de.measite.minidns.Record;
-import de.measite.minidns.Record.CLASS;
-import de.measite.minidns.Record.TYPE;
-import de.measite.minidns.record.A;
-import de.measite.minidns.record.AAAA;
-import de.measite.minidns.record.Data;
-import de.measite.minidns.record.SRV;
-import de.measite.minidns.util.NameUtil;
-import de.pixart.messenger.Config;
-import de.pixart.messenger.xmpp.jid.Jid;
-
-public class DNSHelper {
-
-    public static final Pattern PATTERN_IPV4 = Pattern.compile("\\A(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
-    public static final Pattern PATTERN_IPV6_HEX4DECCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::((?:[0-9A-Fa-f]{1,4}:)*)(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
-    public static final Pattern PATTERN_IPV6_6HEX4DEC = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}:){6,6})(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
-    public static final Pattern PATTERN_IPV6_HEXCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)::((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)\\z");
-    public static final Pattern PATTERN_IPV6 = Pattern.compile("\\A(?:[0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}\\z");
-
-    protected static Client client = new Client();
-
-    protected static Context context;
-
-    public static Bundle getSRVRecord(final Jid jid, Context context) throws IOException {
-        DNSHelper.context = context;
-        final String host = jid.getDomainpart();
-        final List<InetAddress> servers = Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP ? getDnsServers(context) : getDnsServersPreLollipop();
-        Bundle b = new Bundle();
-        boolean interrupted = false;
-        for (InetAddress server : servers) {
-            if (Thread.currentThread().isInterrupted()) {
-                interrupted = true;
-                break;
-            }
-            b = queryDNS(host, server);
-            if (b.containsKey("values")) {
-                return b;
-            }
-        }
-        if (!b.containsKey("values")) {
-            Log.d(Config.LOGTAG, (interrupted ? "Thread interrupted during DNS query" : "all dns queries failed") + ". provide fallback A record");
-            ArrayList<Parcelable> values = new ArrayList<>();
-            values.add(createNamePortBundle(host, 5222, false));
-            b.putParcelableArrayList("values", values);
-        }
-        return b;
-    }
-
-    @TargetApi(21)
-    private static List<InetAddress> getDnsServers(Context context) {
-        List<InetAddress> servers = new ArrayList<>();
-        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
-        Network[] networks = connectivityManager == null ? null : connectivityManager.getAllNetworks();
-        if (networks == null) {
-            return getDnsServersPreLollipop();
-        }
-        for (int i = 0; i < networks.length; ++i) {
-            LinkProperties linkProperties = connectivityManager.getLinkProperties(networks[i]);
-            if (linkProperties != null) {
-                if (hasDefaultRoute(linkProperties)) {
-                    servers.addAll(0, getIPv4First(linkProperties.getDnsServers()));
-                } else {
-                    servers.addAll(getIPv4First(linkProperties.getDnsServers()));
-                }
-            }
-        }
-        if (servers.size() > 0) {
-            Log.d(Config.LOGTAG, "used lollipop variant to discover dns servers in " + networks.length + " networks");
-        }
-        return servers.size() > 0 ? servers : getDnsServersPreLollipop();
-    }
-
-    private static List<InetAddress> getIPv4First(List<InetAddress> in) {
-        List<InetAddress> out = new ArrayList<>();
-        for (InetAddress addr : in) {
-            if (addr instanceof Inet4Address) {
-                out.add(0, addr);
-            } else {
-                out.add(addr);
-            }
-        }
-        return out;
-    }
-
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-    private static boolean hasDefaultRoute(LinkProperties linkProperties) {
-        for (RouteInfo route : linkProperties.getRoutes()) {
-            if (route.isDefaultRoute()) {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    private static List<InetAddress> getDnsServersPreLollipop() {
-        List<InetAddress> servers = new ArrayList<>();
-        String[] dns = client.findDNS();
-        for (int i = 0; i < dns.length; ++i) {
-            try {
-                servers.add(InetAddress.getByName(dns[i]));
-            } catch (UnknownHostException e) {
-                //ignore
-            }
-        }
-        return servers;
-    }
-
-    private static class TlsSrv {
-        private final SRV srv;
-        private final boolean tls;
-
-        public TlsSrv(SRV srv, boolean tls) {
-            this.srv = srv;
-            this.tls = tls;
-        }
-    }
-
-    private static void fillSrvMaps(final String qname, final InetAddress dnsServer, final Map<Integer, List<TlsSrv>> priorities, final Map<String, List<String>> ips4, final Map<String, List<String>> ips6, final boolean tls) throws IOException {
-        final DNSMessage message = client.query(qname, TYPE.SRV, CLASS.IN, dnsServer.getHostAddress());
-        for (Record[] rrset : new Record[][]{message.getAnswers(), message.getAdditionalResourceRecords()}) {
-            for (Record rr : rrset) {
-                Data d = rr.getPayload();
-                final String name = rr.getName() != null ? rr.getName().toLowerCase(Locale.US) : null;
-                if (d instanceof SRV && NameUtil.idnEquals(qname, name)) {
-                    SRV srv = (SRV) d;
-                    if (!priorities.containsKey(srv.getPriority())) {
-                        priorities.put(srv.getPriority(), new ArrayList<TlsSrv>());
-                    }
-                    priorities.get(srv.getPriority()).add(new TlsSrv(srv, tls));
-                } else if (d instanceof SRV) {
-                    Log.d(Config.LOGTAG, "found unrecognized SRV record with name: " + name);
-                }
-                if (d instanceof A) {
-                    A a = (A) d;
-                    if (!ips4.containsKey(name)) {
-                        ips4.put(name, new ArrayList<String>());
-                    }
-                    ips4.get(name).add(a.toString());
-                }
-                if (d instanceof AAAA) {
-                    AAAA aaaa = (AAAA) d;
-                    if (!ips6.containsKey(name)) {
-                        ips6.put(name, new ArrayList<String>());
-                    }
-                    ips6.get(name).add("[" + aaaa.toString() + "]");
-                }
-            }
-        }
-    }
-
-    public static Bundle queryDNS(String host, InetAddress dnsServer) {
-        Bundle bundle = new Bundle();
-        try {
-            client.setTimeout(Config.SOCKET_TIMEOUT * 1000);
-            final String qname = "_xmpp-client._tcp." + host.toLowerCase(Locale.US);
-            final String tlsQname = "_xmpps-client._tcp." + host.toLowerCase(Locale.US);
-            Log.d(Config.LOGTAG, "using dns server: " + dnsServer.getHostAddress() + " to look up " + host);
-
-            final Map<Integer, List<TlsSrv>> priorities = new TreeMap<>();
-            final Map<String, List<String>> ips4 = new TreeMap<>();
-            final Map<String, List<String>> ips6 = new TreeMap<>();
-
-            fillSrvMaps(qname, dnsServer, priorities, ips4, ips6, false);
-            fillSrvMaps(tlsQname, dnsServer, priorities, ips4, ips6, true);
-
-            final List<TlsSrv> result = new ArrayList<>();
-            for (final List<TlsSrv> s : priorities.values()) {
-                result.addAll(s);
-            }
-
-            final ArrayList<Bundle> values = new ArrayList<>();
-            if (result.size() == 0) {
-                DNSMessage response;
-                try {
-                    response = client.query(host, TYPE.A, CLASS.IN, dnsServer.getHostAddress());
-                    for (int i = 0; i < response.getAnswers().length; ++i) {
-                        values.add(createNamePortBundle(host, 5222, response.getAnswers()[i].getPayload(), false));
-                    }
-                } catch (SocketTimeoutException e) {
-                    Log.d(Config.LOGTAG, "ignoring timeout exception when querying A record on " + dnsServer.getHostAddress());
-                }
-                try {
-                    response = client.query(host, TYPE.AAAA, CLASS.IN, dnsServer.getHostAddress());
-                    for (int i = 0; i < response.getAnswers().length; ++i) {
-                        values.add(createNamePortBundle(host, 5222, response.getAnswers()[i].getPayload(), false));
-                    }
-                } catch (SocketTimeoutException e) {
-                    Log.d(Config.LOGTAG, "ignoring timeout exception when querying AAAA record on " + dnsServer.getHostAddress());
-                }
-                values.add(createNamePortBundle(host, 5222, false));
-                bundle.putParcelableArrayList("values", values);
-                return bundle;
-            }
-            for (final TlsSrv tlsSrv : result) {
-                final SRV srv = tlsSrv.srv;
-                final String name = srv.getName() != null ? srv.getName().toLowerCase(Locale.US) : null;
-                if (ips6.containsKey(name)) {
-                    values.add(createNamePortBundle(name, srv.getPort(), ips6, tlsSrv.tls));
-                } else {
-                    try {
-                        DNSMessage response = client.query(name, TYPE.AAAA, CLASS.IN, dnsServer.getHostAddress());
-                        for (int i = 0; i < response.getAnswers().length; ++i) {
-                            values.add(createNamePortBundle(name, srv.getPort(), response.getAnswers()[i].getPayload(), tlsSrv.tls));
-                        }
-                    } catch (SocketTimeoutException e) {
-                        Log.d(Config.LOGTAG, "ignoring timeout exception when querying AAAA record on " + dnsServer.getHostAddress());
-                    }
-                }
-                if (ips4.containsKey(name)) {
-                    values.add(createNamePortBundle(name, srv.getPort(), ips4, tlsSrv.tls));
-                } else {
-                    DNSMessage response = client.query(name, TYPE.A, CLASS.IN, dnsServer.getHostAddress());
-                    for (int i = 0; i < response.getAnswers().length; ++i) {
-                        values.add(createNamePortBundle(name, srv.getPort(), response.getAnswers()[i].getPayload(), tlsSrv.tls));
-                    }
-                }
-                values.add(createNamePortBundle(name, srv.getPort(), tlsSrv.tls));
-            }
-            bundle.putParcelableArrayList("values", values);
-        } catch (SocketTimeoutException e) {
-            bundle.putString("error", "timeout");
-        } catch (Exception e) {
-            bundle.putString("error", "unhandled");
-        }
-        return bundle;
-    }
-
-    private static Bundle createNamePortBundle(String name, int port, final boolean tls) {
-        Bundle namePort = new Bundle();
-        namePort.putString("name", name);
-        namePort.putBoolean("tls", tls);
-        namePort.putInt("port", port);
-        return namePort;
-    }
-
-    private static Bundle createNamePortBundle(String name, int port, Map<String, List<String>> ips, final boolean tls) {
-        Bundle namePort = new Bundle();
-        namePort.putString("name", name);
-        namePort.putBoolean("tls", tls);
-        namePort.putInt("port", port);
-        if (ips != null) {
-            List<String> ip = ips.get(name);
-            Collections.shuffle(ip, new Random());
-            namePort.putString("ip", ip.get(0));
-        }
-        return namePort;
-    }
-
-    private static Bundle createNamePortBundle(String name, int port, Data data, final boolean tls) {
-        Bundle namePort = new Bundle();
-        namePort.putString("name", name);
-        namePort.putBoolean("tls", tls);
-        namePort.putInt("port", port);
-        if (data instanceof A) {
-            namePort.putString("ip", data.toString());
-        } else if (data instanceof AAAA) {
-            namePort.putString("ip", "[" + data.toString() + "]");
-        }
-        return namePort;
-    }
-
-    public static boolean isIp(final String server) {
-        return server != null && (
-                PATTERN_IPV4.matcher(server).matches()
-                        || PATTERN_IPV6.matcher(server).matches()
-                        || PATTERN_IPV6_6HEX4DEC.matcher(server).matches()
-                        || PATTERN_IPV6_HEX4DECCOMPRESSED.matcher(server).matches()
-                        || PATTERN_IPV6_HEXCOMPRESSED.matcher(server).matches());
-    }
-}
diff --git a/src/main/java/de/pixart/messenger/utils/IP.java b/src/main/java/de/pixart/messenger/utils/IP.java
new file mode 100644
index 000000000..42f9ec553
--- /dev/null
+++ b/src/main/java/de/pixart/messenger/utils/IP.java
@@ -0,0 +1,22 @@
+package de.pixart.messenger.utils;
+
+import java.util.regex.Pattern;
+
+public class IP {
+
+    private static final Pattern PATTERN_IPV4 = Pattern.compile("\\A(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
+    private static final Pattern PATTERN_IPV6_HEX4DECCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::((?:[0-9A-Fa-f]{1,4}:)*)(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
+    private static final Pattern PATTERN_IPV6_6HEX4DEC = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}:){6,6})(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
+    private static final Pattern PATTERN_IPV6_HEXCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)::((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)\\z");
+    private static final Pattern PATTERN_IPV6 = Pattern.compile("\\A(?:[0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}\\z");
+
+    public static boolean matches(String server) {
+        return server != null && (
+                PATTERN_IPV4.matcher(server).matches()
+                        || PATTERN_IPV6.matcher(server).matches()
+                        || PATTERN_IPV6_6HEX4DEC.matcher(server).matches()
+                        || PATTERN_IPV6_HEX4DECCOMPRESSED.matcher(server).matches()
+                        || PATTERN_IPV6_HEXCOMPRESSED.matcher(server).matches());
+    }
+
+}
\ No newline at end of file
diff --git a/src/main/java/de/pixart/messenger/utils/Resolver.java b/src/main/java/de/pixart/messenger/utils/Resolver.java
new file mode 100644
index 000000000..a5bcad547
--- /dev/null
+++ b/src/main/java/de/pixart/messenger/utils/Resolver.java
@@ -0,0 +1,159 @@
+package de.pixart.messenger.utils;
+
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.util.Log;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import de.measite.minidns.DNSClient;
+import de.measite.minidns.DNSName;
+import de.measite.minidns.Question;
+import de.measite.minidns.Record;
+import de.measite.minidns.hla.DnssecResolverApi;
+import de.measite.minidns.hla.ResolverResult;
+import de.measite.minidns.record.A;
+import de.measite.minidns.record.AAAA;
+import de.measite.minidns.record.Data;
+import de.measite.minidns.record.InternetAddressRR;
+import de.measite.minidns.record.SRV;
+import de.pixart.messenger.Config;
+
+public class Resolver {
+
+    private static final String DIRECT_TLS_SERVICE = "_xmpps-client";
+    private static final String STARTTLS_SERICE = "_xmpp-client";
+
+    public static void registerLookupMechanism(Context context) {
+        DNSClient.addDnsServerLookupMechanism(new AndroidUsingLinkProperties(context));
+    }
+
+    public static List<Result> resolve(String domain) {
+        List<Result> results = new ArrayList<>();
+        try {
+            results.addAll(resolveSrv(domain, true));
+        } catch (IOException e) {
+            //ignore
+        }
+        try {
+            results.addAll(resolveSrv(domain, false));
+        } catch (IOException e) {
+            //ignore
+        }
+        if (results.size() == 0) {
+            results.add(Result.createDefault(domain));
+        }
+        Collections.sort(results);
+        return results;
+    }
+
+    private static List<Result> resolveSrv(String domain, final boolean directTls) throws IOException {
+        Question question = new Question((directTls ? DIRECT_TLS_SERVICE : STARTTLS_SERICE) + "._tcp." + domain, Record.TYPE.SRV);
+        ResolverResult<Data> result = DnssecResolverApi.INSTANCE.resolve(question);
+        List<Result> results = new ArrayList<>();
+        for (Data record : result.getAnswersOrEmptySet()) {
+            if (record instanceof SRV) {
+                SRV srvRecord = (SRV) record;
+                boolean added = results.addAll(resolveIp(srvRecord, A.class, result.isAuthenticData(), directTls));
+                added |= results.addAll(resolveIp(srvRecord, AAAA.class, result.isAuthenticData(), directTls));
+                if (!added) {
+                    Result resolverResult = Result.fromRecord(srvRecord, directTls);
+                    resolverResult.authenticated = resolverResult.isAuthenticated();
+                    results.add(resolverResult);
+                }
+            }
+        }
+        return results;
+    }
+
+    private static <D extends InternetAddressRR> List<Result> resolveIp(SRV srv, Class<D> type, boolean authenticated, boolean directTls) {
+        List<Result> list = new ArrayList<>();
+        try {
+            ResolverResult<D> results = DnssecResolverApi.INSTANCE.resolve(srv.name, type);
+            for (D record : results.getAnswersOrEmptySet()) {
+                Result resolverResult = Result.fromRecord(srv, directTls);
+                resolverResult.authenticated = results.isAuthenticData() && authenticated;
+                resolverResult.ip = record.getInetAddress();
+                list.add(resolverResult);
+            }
+        } catch (IOException e) {
+            Log.d(Config.LOGTAG, e.getMessage());
+            //ignore. will add default record later
+        }
+        return list;
+    }
+
+    public static class Result implements Comparable<Result> {
+        private InetAddress ip;
+        private DNSName hostname;
+        private int port = 5222;
+        private boolean directTls = false;
+        private boolean authenticated = false;
+        private int priority;
+
+        public InetAddress getIp() {
+            return ip;
+        }
+
+        public int getPort() {
+            return port;
+        }
+
+        public DNSName getHostname() {
+            return hostname;
+        }
+
+        public boolean isDirectTls() {
+            return directTls;
+        }
+
+        public boolean isAuthenticated() {
+            return authenticated;
+        }
+
+        @Override
+        public String toString() {
+            return "Result{" +
+                    "ip='" + ip + '\'' +
+                    ", hostame='" + hostname.toString() + '\'' +
+                    ", port=" + port +
+                    ", directTls=" + directTls +
+                    ", authenticated=" + authenticated +
+                    ", priority=" + priority +
+                    '}';
+        }
+
+        @Override
+        public int compareTo(@NonNull Result result) {
+            if (result.priority == priority) {
+                if (directTls == result.directTls) {
+                    return 0;
+                } else {
+                    return directTls ? 1 : -1;
+                }
+            } else {
+                return priority - result.priority;
+            }
+        }
+
+        public static Result fromRecord(SRV srv, boolean directTls) {
+            Result result = new Result();
+            result.port = srv.port;
+            result.hostname = srv.name;
+            result.directTls = directTls;
+            result.priority = srv.priority;
+            return result;
+        }
+
+        public static Result createDefault(String domain) {
+            Result result = new Result();
+            result.port = 5222;
+            result.hostname = DNSName.from(domain);
+            return result;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/de/pixart/messenger/xmpp/XmppConnection.java b/src/main/java/de/pixart/messenger/xmpp/XmppConnection.java
index f3ce20da3..a62f5c2d3 100644
--- a/src/main/java/de/pixart/messenger/xmpp/XmppConnection.java
+++ b/src/main/java/de/pixart/messenger/xmpp/XmppConnection.java
@@ -2,8 +2,6 @@ package de.pixart.messenger.xmpp;
 
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
-import android.os.Bundle;
-import android.os.Parcelable;
 import android.os.PowerManager;
 import android.os.PowerManager.WakeLock;
 import android.os.SystemClock;
@@ -20,7 +18,6 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.math.BigInteger;
 import java.net.ConnectException;
-import java.net.IDN;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.Socket;
@@ -69,9 +66,10 @@ import de.pixart.messenger.generator.IqGenerator;
 import de.pixart.messenger.services.NotificationService;
 import de.pixart.messenger.services.XmppConnectionService;
 import de.pixart.messenger.ui.EditAccountActivity;
-import de.pixart.messenger.utils.DNSHelper;
+import de.pixart.messenger.utils.IP;
 import de.pixart.messenger.utils.Namespace;
 import de.pixart.messenger.utils.Patterns;
+import de.pixart.messenger.utils.Resolver;
 import de.pixart.messenger.utils.SSLSocketHelper;
 import de.pixart.messenger.utils.SocksSocketFactory;
 import de.pixart.messenger.xml.Element;
@@ -357,7 +355,7 @@ public class XmppConnection implements Runnable {
                 } catch (Exception e) {
                     throw new IOException(e.getMessage());
                 }
-            } else if (DNSHelper.isIp(account.getServer().toString())) {
+            } else if (IP.matches(account.getServer().toString())) {
                 localSocket = new Socket();
                 try {
                     localSocket.connect(new InetSocketAddress(account.getServer().toString(), 5222), Config.SOCKET_TIMEOUT * 1000);
@@ -373,37 +371,28 @@ public class XmppConnection implements Runnable {
                     throw new IOException(e.getMessage());
                 }
             } else {
-                final Bundle result = DNSHelper.getSRVRecord(account.getServer(), mXmppConnectionService);
-                final ArrayList<Parcelable> values = result.getParcelableArrayList("values");
-                for (Iterator<Parcelable> iterator = values.iterator(); iterator.hasNext(); ) {
+                List<Resolver.Result> results = Resolver.resolve(account.getJid().getDomainpart());
+                Log.d(Config.LOGTAG, "results: " + results);
+                for (Iterator<Resolver.Result> iterator = results.iterator(); iterator.hasNext(); ) {
+                    final Resolver.Result result = iterator.next();
                     if (Thread.currentThread().isInterrupted()) {
                         Log.d(Config.LOGTAG, account.getJid().toBareJid() + ": Thread was interrupted");
                         return;
                     }
-                    final Bundle namePort = (Bundle) iterator.next();
                     try {
-                        String srvRecordServer;
-                        try {
-                            srvRecordServer = IDN.toASCII(namePort.getString("name"));
-                        } catch (final IllegalArgumentException e) {
-                            // TODO: Handle me?`
-                            srvRecordServer = "";
-                        }
-                        final int srvRecordPort = namePort.getInt("port");
-                        final String srvIpServer = namePort.getString("ip");
                         // if tls is true, encryption is implied and must not be started
-                        features.encryptionEnabled = namePort.getBoolean("tls");
+                        features.encryptionEnabled = result.isDirectTls();
                         final InetSocketAddress addr;
-                        if (srvIpServer != null) {
-                            addr = new InetSocketAddress(srvIpServer, srvRecordPort);
+                        if (result.getIp() != null) {
+                            addr = new InetSocketAddress(result.getIp(), result.getPort());
                             Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
-                                    + ": using values from dns " + srvRecordServer
-                                    + "[" + srvIpServer + "]:" + srvRecordPort + " tls: " + features.encryptionEnabled);
+                                    + ": using values from dns " + result.getHostname().toString()
+                                    + "[" + result.getIp().toString() + "]:" + result.getPort() + " tls: " + features.encryptionEnabled);
                         } else {
-                            addr = new InetSocketAddress(srvRecordServer, srvRecordPort);
+                            addr = new InetSocketAddress(result.getHostname().toString(), result.getPort());
                             Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
                                     + ": using values from dns "
-                                    + srvRecordServer + ":" + srvRecordPort + " tls: " + features.encryptionEnabled);
+                                    + result.getHostname().toString() + ":" + result.getPort() + " tls: " + features.encryptionEnabled);
                         }
 
                         if (!features.encryptionEnabled) {