www: no more xmpp

9 files changed, 773 insertions, 0 deletions

diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/BasicXmppSession.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/BasicXmppSession.java
new file mode 100644
index 00000000..647f2717
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/BasicXmppSession.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2008-2017, Juick
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.juick.server.xmpp.s2s;
+
+import rocks.xmpp.addr.Jid;
+import rocks.xmpp.core.XmppException;
+import rocks.xmpp.core.session.ConnectionConfiguration;
+import rocks.xmpp.core.session.XmppSession;
+import rocks.xmpp.core.session.XmppSessionConfiguration;
+import rocks.xmpp.core.stanza.model.IQ;
+import rocks.xmpp.core.stanza.model.Message;
+import rocks.xmpp.core.stanza.model.Presence;
+import rocks.xmpp.core.stanza.model.server.ServerIQ;
+import rocks.xmpp.core.stanza.model.server.ServerMessage;
+import rocks.xmpp.core.stanza.model.server.ServerPresence;
+import rocks.xmpp.core.stream.model.StreamElement;
+
+/**
+ * Created by vitalyster on 06.02.2017.
+ */
+public class BasicXmppSession extends XmppSession {
+    protected BasicXmppSession(String xmppServiceDomain, XmppSessionConfiguration configuration, ConnectionConfiguration... connectionConfigurations) {
+        super(xmppServiceDomain, configuration, connectionConfigurations);
+    }
+
+    public static BasicXmppSession create(String xmppServiceDomain, XmppSessionConfiguration configuration) {
+        BasicXmppSession session = new BasicXmppSession(xmppServiceDomain, configuration);
+        notifyCreationListeners(session);
+        return session;
+    }
+
+    @Override
+    public void connect(Jid from) throws XmppException {
+
+    }
+
+    @Override
+    public Jid getConnectedResource() {
+        return null;
+    }
+
+    @Override
+    protected StreamElement prepareElement(StreamElement element) {
+        if (element instanceof Message) {
+            element = ServerMessage.from((Message) element);
+        } else if (element instanceof Presence) {
+            element = ServerPresence.from((Presence) element);
+        } else if (element instanceof IQ) {
+            element = ServerIQ.from((IQ) element);
+        }
+
+        return element;
+    }
+}
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/CacheEntry.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/CacheEntry.java
new file mode 100644
index 00000000..33e875bd
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/CacheEntry.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2008-2017, Juick
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.juick.server.xmpp.s2s;
+
+import rocks.xmpp.addr.Jid;
+
+import java.time.Instant;
+
+/**
+ *
+ * @author ugnich
+ */
+public class CacheEntry {
+
+    public Jid hostname;
+    public Instant created;
+    public Instant updated;
+    public String xml;
+
+    public CacheEntry(Jid hostname, String xml) {
+        this.hostname = hostname;
+        this.created = this.updated =Instant.now();
+        this.xml = xml;
+    }
+}
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/Connection.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/Connection.java
new file mode 100644
index 00000000..6bf61169
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/Connection.java
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2008-2017, Juick
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.juick.server.xmpp.s2s;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.juick.server.XMPPServer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
+import org.xmlpull.v1.XmlPullParserFactory;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.net.Socket;
+import java.nio.charset.StandardCharsets;
+import java.time.Instant;
+import java.util.UUID;
+
+/**
+ *
+ * @author ugnich
+ */
+public class Connection {
+
+    protected static final Logger logger = LoggerFactory.getLogger(Connection.class);
+
+    public String streamID;
+    public Instant created;
+    public Instant updated;
+    public long bytesLocal = 0;
+    public long packetsLocal = 0;
+    XMPPServer xmpp;
+    private Socket socket;
+    public static final String NS_DB = "jabber:server:dialback";
+    public static final String NS_TLS = "urn:ietf:params:xml:ns:xmpp-tls";
+    public static final String NS_STREAM = "http://etherx.jabber.org/streams";
+    XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
+    XmlPullParser parser = factory.newPullParser();
+    OutputStreamWriter writer;
+    private boolean secured = false;
+
+
+
+    public Connection(XMPPServer xmpp) throws XmlPullParserException {
+        this.xmpp = xmpp;
+        created = updated = Instant.now();
+    }
+
+    public void logParser() {
+        if (streamID == null) {
+            return;
+        }
+        String tag = "IN: <" + parser.getName();
+        for (int i = 0; i < parser.getAttributeCount(); i++) {
+            tag += " " + parser.getAttributeName(i) + "=\"" + parser.getAttributeValue(i) + "\"";
+        }
+        tag += ">...</" + parser.getName() + ">\n";
+        logger.trace(tag);
+    }
+
+    public void sendStanza(String xml) {
+        if (streamID != null) {
+            logger.trace("OUT: {}\n", xml);
+        }
+        try {
+            writer.write(xml);
+            writer.flush();
+        } catch (IOException e) {
+            logger.error("send stanza failed", e);
+        }
+
+        updated = Instant.now();
+        bytesLocal += xml.length();
+        packetsLocal++;
+    }
+
+    public void closeConnection() {
+        if (streamID != null) {
+            logger.debug("closing stream {}", streamID);
+        }
+
+        try {
+            writer.write("</stream:stream>");
+        } catch (Exception e) {
+        }
+
+        try {
+            writer.close();
+        } catch (Exception e) {
+        }
+
+        try {
+            socket.close();
+        } catch (Exception e) {
+        }
+    }
+
+    public boolean isSecured() {
+        return secured;
+    }
+
+    public void setSecured(boolean secured) {
+        this.secured = secured;
+    }
+
+    public void restartParser() throws XmlPullParserException, IOException {
+        streamID = UUID.randomUUID().toString();
+        parser = factory.newPullParser();
+        parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
+        parser.setInput(new InputStreamReader(socket.getInputStream()));
+        writer = new OutputStreamWriter(socket.getOutputStream(), StandardCharsets.UTF_8);
+    }
+
+    @JsonIgnore
+    public Socket getSocket() {
+        return socket;
+    }
+
+    public void setSocket(Socket socket) {
+        this.socket = socket;
+    }
+}
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/ConnectionIn.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/ConnectionIn.java
new file mode 100644
index 00000000..9ee81d4d
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/ConnectionIn.java
@@ -0,0 +1,213 @@
+/*
+ * Copyright (C) 2008-2017, Juick
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.juick.server.xmpp.s2s;
+
+import com.juick.server.XMPPServer;
+import com.juick.xmpp.extensions.StreamError;
+import com.juick.xmpp.utils.XmlUtils;
+import org.apache.commons.lang3.StringUtils;
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
+import rocks.xmpp.addr.Jid;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.net.Socket;
+import java.net.SocketException;
+import java.time.Instant;
+import java.util.Arrays;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+/**
+ * @author ugnich
+ */
+public class ConnectionIn extends Connection implements Runnable {
+
+    final public List<Jid> from = new CopyOnWriteArrayList<>();
+    public Instant received;
+    public long packetsRemote = 0;
+    ConnectionListener listener;
+
+    public ConnectionIn(XMPPServer xmpp, Socket socket) throws XmlPullParserException, IOException {
+        super(xmpp);
+        this.setSocket(socket);
+        restartParser();
+    }
+
+    @Override
+    public void run() {
+        try {
+            parser.next(); // stream:stream
+            updateTsRemoteData();
+            if (!parser.getName().equals("stream")
+                    || !parser.getNamespace("stream").equals(NS_STREAM)) {
+//                    || !parser.getAttributeValue(null, "version").equals("1.0")
+//                    || !parser.getAttributeValue(null, "to").equals(Main.HOSTNAME)) {
+                throw new Exception(String.format("stream from %s invalid", getSocket().getRemoteSocketAddress()));
+            }
+            streamID = parser.getAttributeValue(null, "id");
+            if (streamID == null) {
+                streamID = UUID.randomUUID().toString();
+            }
+            boolean xmppversionnew = parser.getAttributeValue(null, "version") != null;
+            String from = parser.getAttributeValue(null, "from");
+
+            if (Arrays.asList(xmpp.bannedHosts).contains(from)) {
+                closeConnection();
+                return;
+            }
+            sendOpenStream(from, xmppversionnew);
+
+            while (parser.next() != XmlPullParser.END_DOCUMENT) {
+                updateTsRemoteData();
+                if (parser.getEventType() != XmlPullParser.START_TAG) {
+                    continue;
+                }
+                logParser();
+
+                packetsRemote++;
+
+                String tag = parser.getName();
+                if (tag.equals("result") && parser.getNamespace().equals(NS_DB)) {
+                    String dfrom = parser.getAttributeValue(null, "from");
+                    String to = parser.getAttributeValue(null, "to");
+                    logger.debug("stream from {} to {} {} asking for dialback", dfrom, to, streamID);
+                    if (dfrom.endsWith(xmpp.getJid().toEscapedString()) && (dfrom.equals(xmpp.getJid().toEscapedString())
+                            || dfrom.endsWith("." + xmpp.getJid()))) {
+                        logger.warn("stream from {} is invalid", dfrom);
+                        break;
+                    }
+                    if (to != null && to.equals(xmpp.getJid().toEscapedString())) {
+                        String dbKey = XmlUtils.getTagText(parser);
+                        updateTsRemoteData();
+                        xmpp.startDialback(Jid.of(dfrom), streamID, dbKey);
+                    } else {
+                        logger.warn("stream from " + dfrom + " " + streamID + " invalid to " + to);
+                        break;
+                    }
+                } else if (tag.equals("verify") && parser.getNamespace().equals(NS_DB)) {
+                    String vfrom = parser.getAttributeValue(null, "from");
+                    String vto = parser.getAttributeValue(null, "to");
+                    String vid = parser.getAttributeValue(null, "id");
+                    String vkey = XmlUtils.getTagText(parser);
+                    updateTsRemoteData();
+                    final boolean[] valid = {false};
+                    if (vfrom != null && vto != null && vid != null && vkey != null) {
+                        xmpp.getConnectionOut(Jid.of(vfrom), false).ifPresent(c -> {
+                            String dialbackKey = c.dbKey;
+                            valid[0] = vkey.equals(dialbackKey);
+                        });
+                    }
+                    if (valid[0]) {
+                        sendStanza("<db:verify from='" + vto + "' to='" + vfrom + "' id='" + vid + "' type='valid'/>");
+                        logger.debug("stream from {} {} dialback verify valid", vfrom, streamID);
+                    } else {
+                        sendStanza("<db:verify from='" + vto + "' to='" + vfrom + "' id='" + vid + "' type='invalid'/>");
+                        logger.warn("stream from {} {} dialback verify invalid", vfrom, streamID);
+                    }
+                } else if (tag.equals("presence") && checkFromTo(parser)) {
+                    String xml = XmlUtils.parseToString(parser, false);
+                    logger.debug("stream {} presence: {}", streamID, xml);
+                    xmpp.onStanzaReceived(xml);
+                } else if (tag.equals("message") && checkFromTo(parser)) {
+                    updateTsRemoteData();
+                    String xml = XmlUtils.parseToString(parser, false);
+                    logger.debug("stream {} message: {}", streamID, xml);
+                    xmpp.onStanzaReceived(xml);
+
+                } else if (tag.equals("iq") && checkFromTo(parser)) {
+                    updateTsRemoteData();
+                    String type = parser.getAttributeValue(null, "type");
+                    String xml = XmlUtils.parseToString(parser, false);
+                    if (type == null || !type.equals("error")) {
+                        logger.debug("stream {} iq: {}", streamID, xml);
+                        xmpp.onStanzaReceived(xml);
+                    }
+                } else if (!isSecured() && tag.equals("starttls")) {
+                    listener.starttls(this);
+                } else if (isSecured() && tag.equals("stream") && parser.getNamespace().equals(NS_STREAM)) {
+                    sendOpenStream(null, true);
+                } else if (tag.equals("error")) {
+                    StreamError streamError = StreamError.parse(parser);
+                    logger.debug("Stream error from {}: {}", streamID, streamError.getCondition());
+                    xmpp.removeConnectionIn(this);
+                    closeConnection();
+                } else {
+                    String unhandledStanza = XmlUtils.parseToString(parser, true);
+                    logger.warn("Unhandled stanza from {}: {}", streamID, unhandledStanza);
+                }
+            }
+            logger.warn("stream {} finished", streamID);
+            xmpp.removeConnectionIn(this);
+            closeConnection();
+        } catch (EOFException | SocketException ex) {
+            logger.debug("stream {} closed (dirty)", streamID);
+            xmpp.removeConnectionIn(this);
+            closeConnection();
+        } catch (Exception e) {
+            logger.debug("stream {} error {}", streamID, e);
+            xmpp.removeConnectionIn(this);
+            closeConnection();
+        }
+    }
+
+    void updateTsRemoteData() {
+        received = Instant.now();
+    }
+
+    void sendOpenStream(String from, boolean xmppversionnew) throws IOException {
+        String openStream = "<?xml version='1.0'?><stream:stream xmlns='jabber:server' " +
+                "xmlns:stream='http://etherx.jabber.org/streams' xmlns:db='jabber:server:dialback' from='" +
+                xmpp.getJid().toEscapedString() + "' id='" + streamID + "' version='1.0'>";
+        if (xmppversionnew) {
+            openStream += "<stream:features>";
+            if (listener != null && listener.isTlsAvailable() && !isSecured() && !Arrays.asList(xmpp.brokenSSLhosts).contains(from)) {
+                openStream += "<starttls xmlns=\"" + NS_TLS + "\"><optional/></starttls>";
+            }
+            openStream += "</stream:features>";
+        }
+        sendStanza(openStream);
+    }
+
+    public void sendDialbackResult(Jid sfrom, String type) {
+        sendStanza("<db:result from='" + xmpp.getJid().toEscapedString() + "' to='" + sfrom + "' type='" + type + "'/>");
+        if (type.equals("valid")) {
+            from.add(sfrom);
+            logger.debug("stream from {} {} ready", sfrom, streamID);
+        }
+    }
+
+    boolean checkFromTo(XmlPullParser parser) throws Exception {
+        String cfrom = parser.getAttributeValue(null, "from");
+        String cto = parser.getAttributeValue(null, "to");
+        if (StringUtils.isNotEmpty(cfrom) && StringUtils.isNotEmpty(cto)) {
+            Jid jidfrom = Jid.of(cfrom);
+            for (Jid aFrom : from) {
+                if (aFrom.equals(Jid.of(jidfrom.getDomain()))) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+    public void setListener(ConnectionListener listener) {
+        this.listener = listener;
+    }
+}
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/ConnectionListener.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/ConnectionListener.java
new file mode 100644
index 00000000..fde7a0e7
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/ConnectionListener.java
@@ -0,0 +1,15 @@
+package com.juick.server.xmpp.s2s;
+
+import com.juick.xmpp.extensions.StreamError;
+
+public interface ConnectionListener {
+    boolean isTlsAvailable();
+    void starttls(ConnectionIn connection);
+    void proceed(ConnectionOut connection);
+    void verify(ConnectionOut connection, String from, String type, String sid);
+    void dialbackError(ConnectionOut connection, StreamError error);
+    void finished(ConnectionOut connection, boolean dirty);
+    void exception(ConnectionOut connection, Exception ex);
+    void ready(ConnectionOut connection);
+    boolean securing(ConnectionOut connection);
+}
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/ConnectionOut.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/ConnectionOut.java
new file mode 100644
index 00000000..e3bd53e9
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/ConnectionOut.java
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2008-2017, Juick
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.juick.server.xmpp.s2s;
+
+import com.juick.server.xmpp.s2s.util.DialbackUtils;
+import com.juick.xmpp.Stream;
+import com.juick.xmpp.extensions.StreamError;
+import com.juick.xmpp.extensions.StreamFeatures;
+import com.juick.xmpp.utils.XmlUtils;
+import org.apache.commons.text.RandomStringGenerator;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.xmlpull.v1.XmlPullParser;
+import rocks.xmpp.addr.Jid;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.SocketException;
+import java.util.UUID;
+
+/**
+ * @author ugnich
+ */
+public class ConnectionOut extends Stream {
+    protected static final Logger logger = LoggerFactory.getLogger(ConnectionOut.class);
+    public static final String NS_TLS = "urn:ietf:params:xml:ns:xmpp-tls";
+    public static final String NS_DB = "jabber:server:dialback";
+    private boolean secured = false;
+
+    public boolean streamReady = false;
+    String checkSID = null;
+    String dbKey = null;
+    private String streamID;
+    ConnectionListener listener;
+    RandomStringGenerator generator = new RandomStringGenerator.Builder().withinRange('a', 'z').build();
+
+    public ConnectionOut(Jid from, Jid to, InputStream is, OutputStream os, String checkSID, String dbKey) throws Exception {
+        super(from, to, is, os);
+        this.to = to;
+        this.checkSID = checkSID;
+        this.dbKey = dbKey;
+        if (dbKey == null) {
+            this.dbKey = DialbackUtils.generateDialbackKey(generator.generate(15), to, from, streamID);
+        }
+        streamID = UUID.randomUUID().toString();
+    }
+
+    public void sendOpenStream() throws IOException {
+        send("<?xml version='1.0'?><stream:stream xmlns='jabber:server' id='" + streamID +
+                "' xmlns:stream='http://etherx.jabber.org/streams' xmlns:db='jabber:server:dialback' from='" +
+                from.toEscapedString()  + "' to='" + to.toEscapedString() + "' version='1.0'>");
+    }
+
+    void processDialback() throws Exception {
+        if (checkSID != null) {
+            sendDialbackVerify(checkSID, dbKey);
+        }
+        send("<db:result from='" + from.toEscapedString() + "' to='" + to.toEscapedString() + "'>" +
+                 dbKey + "</db:result>");
+    }
+
+    @Override
+    public void handshake() {
+        try {
+            restartStream();
+
+            sendOpenStream();
+
+            parser.next(); // stream:stream
+            streamID = parser.getAttributeValue(null, "id");
+            if (streamID == null || streamID.isEmpty()) {
+                throw new Exception("stream to " + to + " invalid first packet");
+            }
+
+            logger.debug("stream to {} {} open", to, streamID);
+            boolean xmppversionnew = parser.getAttributeValue(null, "version") != null;
+            if (!xmppversionnew) {
+                processDialback();
+            }
+
+            while (parser.next() != XmlPullParser.END_DOCUMENT) {
+                if (parser.getEventType() != XmlPullParser.START_TAG) {
+                    continue;
+                }
+
+                String tag = parser.getName();
+                if (tag.equals("result") && parser.getNamespace().equals(NS_DB)) {
+                    String type = parser.getAttributeValue(null, "type");
+                    if (type != null && type.equals("valid")) {
+                        streamReady = true;
+                        listener.ready(this);
+                    } else {
+                        logger.warn("stream to {} {} dialback fail", to, streamID);
+                    }
+                    XmlUtils.skip(parser);
+                } else if (tag.equals("verify") && parser.getNamespace().equals(NS_DB)) {
+                    String from = parser.getAttributeValue(null, "from");
+                    String type = parser.getAttributeValue(null, "type");
+                    String sid = parser.getAttributeValue(null, "id");
+                    listener.verify(this, from, type, sid);
+                    XmlUtils.skip(parser);
+                } else if (tag.equals("features") && parser.getNamespace().equals(NS_STREAM)) {
+                    StreamFeatures features = StreamFeatures.parse(parser);
+                    if (listener != null && !secured && features.STARTTLS >= 0
+                            && listener.securing(this)) {
+                        logger.debug("stream to {} {} securing", to.toEscapedString(), streamID);
+                        send("<starttls xmlns=\"" + NS_TLS + "\" />");
+                    } else {
+                        processDialback();
+                    }
+                } else if (tag.equals("proceed") && parser.getNamespace().equals(NS_TLS)) {
+                    listener.proceed(this);
+                } else if (secured && tag.equals("stream") && parser.getNamespace().equals(NS_STREAM)) {
+                    streamID = parser.getAttributeValue(null, "id");
+                } else if (tag.equals("error")) {
+                    StreamError streamError = StreamError.parse(parser);
+                    listener.dialbackError(this, streamError);
+                } else {
+                    String unhandledStanza = XmlUtils.parseToString(parser, true);
+                    logger.warn("Unhandled stanza from {} {} : {}", to, streamID, unhandledStanza);
+                }
+            }
+            listener.finished(this, false);
+        } catch (EOFException | SocketException eofex) {
+            listener.finished(this, true);
+        } catch (Exception e) {
+            listener.exception(this, e);
+        }
+    }
+
+    public void sendDialbackVerify(String sid, String key) {
+        send("<db:verify from='" + from.toEscapedString() + "' to='" + to + "' id='" + sid + "'>" +
+                key + "</db:verify>");
+    }
+    public void setListener(ConnectionListener listener) {
+        this.listener = listener;
+    }
+
+    public String getStreamID() {
+        return streamID;
+    }
+
+    public boolean isSecured() {
+        return secured;
+    }
+
+    public void setSecured(boolean secured) {
+        this.secured = secured;
+    }
+}
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/DNSQueries.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/DNSQueries.java
new file mode 100644
index 00000000..1367d333
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/DNSQueries.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2008-2017, Juick
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.juick.server.xmpp.s2s;
+
+import org.apache.commons.lang3.math.NumberUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.net.InetSocketAddress;
+import java.util.Hashtable;
+import java.util.Random;
+import javax.naming.NamingException;
+import javax.naming.directory.Attribute;
+import javax.naming.directory.DirContext;
+import javax.naming.directory.InitialDirContext;
+
+/**
+ *
+ * @author ugnich
+ */
+public class DNSQueries {
+
+    private static final Logger logger = LoggerFactory.getLogger(DNSQueries.class);
+
+    private static Random rand = new Random();
+
+    public static InetSocketAddress getServerAddress(String hostname) {
+
+        String host = hostname;
+        int port = 5269;
+
+        Hashtable<String, String> env = new Hashtable<>(5);
+        env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
+        try {
+            DirContext ctx = new InitialDirContext(env);
+            Attribute att = ctx.getAttributes("_xmpp-server._tcp." + hostname, new String[]{"SRV"}).get("SRV");
+
+            if (att != null && att.size() > 0) {
+                int i = rand.nextInt(att.size());
+                String srv[] = att.get(i).toString().split(" ");
+                port = NumberUtils.toInt(srv[2], 5269);
+                host = srv[3];
+            }
+            ctx.close();
+        } catch (NamingException e) {
+            logger.debug("SRV record for {} is not resolved, falling back to A record", hostname);
+        }
+        return new InetSocketAddress(host, port);
+    }
+}
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/StanzaListener.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/StanzaListener.java
new file mode 100644
index 00000000..6932298f
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/StanzaListener.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2008-2017, Juick
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.juick.server.xmpp.s2s;
+
+
+import rocks.xmpp.core.stanza.model.Stanza;
+
+/**
+ * Created by vitalyster on 07.12.2016.
+ */
+public interface StanzaListener {
+    void stanzaReceived(Stanza xmlValue);
+}
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/util/DialbackUtils.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/util/DialbackUtils.java
new file mode 100644
index 00000000..d25dbad8
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/util/DialbackUtils.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2008-2017, Juick
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.juick.server.xmpp.s2s.util;
+
+import org.apache.commons.codec.digest.DigestUtils;
+import org.apache.commons.codec.digest.HmacAlgorithms;
+import org.apache.commons.codec.digest.HmacUtils;
+import rocks.xmpp.addr.Jid;
+
+/**
+ * Created by vitalyster on 05.12.2016.
+ */
+public class DialbackUtils {
+    private DialbackUtils() {
+        throw new IllegalStateException();
+    }
+
+    public static String generateDialbackKey(String secret, Jid to, Jid from, String id) {
+        return new HmacUtils(HmacAlgorithms.HMAC_SHA_256, DigestUtils.sha256(secret))
+                .hmacHex(to.toEscapedString() + " " + from.toEscapedString() + " " + id);
+    }
+}