XmppConnection.java

   1package eu.siacs.conversations.xmpp;
   2
   3import android.content.Context;
   4import android.content.SharedPreferences;
   5import android.os.Bundle;
   6import android.os.Parcelable;
   7import android.os.PowerManager;
   8import android.os.PowerManager.WakeLock;
   9import android.os.SystemClock;
  10import android.preference.PreferenceManager;
  11import android.util.Log;
  12import android.util.Pair;
  13import android.util.SparseArray;
  14
  15import org.apache.http.conn.ssl.StrictHostnameVerifier;
  16import org.json.JSONException;
  17import org.json.JSONObject;
  18import org.xmlpull.v1.XmlPullParserException;
  19
  20import java.io.IOException;
  21import java.io.InputStream;
  22import java.io.OutputStream;
  23import java.math.BigInteger;
  24import java.net.ConnectException;
  25import java.net.IDN;
  26import java.net.InetAddress;
  27import java.net.InetSocketAddress;
  28import java.net.Socket;
  29import java.net.UnknownHostException;
  30import java.security.KeyManagementException;
  31import java.security.NoSuchAlgorithmException;
  32import java.util.ArrayList;
  33import java.util.Arrays;
  34import java.util.Collection;
  35import java.util.HashMap;
  36import java.util.Hashtable;
  37import java.util.LinkedList;
  38import java.util.List;
  39import java.util.Map;
  40import java.util.Map.Entry;
  41
  42import javax.net.ssl.HostnameVerifier;
  43import javax.net.ssl.SSLContext;
  44import javax.net.ssl.SSLSocket;
  45import javax.net.ssl.SSLSocketFactory;
  46import javax.net.ssl.X509TrustManager;
  47
  48import eu.siacs.conversations.Config;
  49import eu.siacs.conversations.crypto.sasl.DigestMd5;
  50import eu.siacs.conversations.crypto.sasl.Plain;
  51import eu.siacs.conversations.crypto.sasl.SaslMechanism;
  52import eu.siacs.conversations.crypto.sasl.ScramSha1;
  53import eu.siacs.conversations.entities.Account;
  54import eu.siacs.conversations.generator.IqGenerator;
  55import eu.siacs.conversations.services.XmppConnectionService;
  56import eu.siacs.conversations.utils.CryptoHelper;
  57import eu.siacs.conversations.utils.DNSHelper;
  58import eu.siacs.conversations.utils.Xmlns;
  59import eu.siacs.conversations.xml.Element;
  60import eu.siacs.conversations.xml.Tag;
  61import eu.siacs.conversations.xml.TagWriter;
  62import eu.siacs.conversations.xml.XmlReader;
  63import eu.siacs.conversations.xmpp.jid.InvalidJidException;
  64import eu.siacs.conversations.xmpp.jid.Jid;
  65import eu.siacs.conversations.xmpp.jingle.OnJinglePacketReceived;
  66import eu.siacs.conversations.xmpp.jingle.stanzas.JinglePacket;
  67import eu.siacs.conversations.xmpp.stanzas.AbstractStanza;
  68import eu.siacs.conversations.xmpp.stanzas.IqPacket;
  69import eu.siacs.conversations.xmpp.stanzas.MessagePacket;
  70import eu.siacs.conversations.xmpp.stanzas.PresencePacket;
  71import eu.siacs.conversations.xmpp.stanzas.csi.ActivePacket;
  72import eu.siacs.conversations.xmpp.stanzas.csi.InactivePacket;
  73import eu.siacs.conversations.xmpp.stanzas.streammgmt.AckPacket;
  74import eu.siacs.conversations.xmpp.stanzas.streammgmt.EnablePacket;
  75import eu.siacs.conversations.xmpp.stanzas.streammgmt.RequestPacket;
  76import eu.siacs.conversations.xmpp.stanzas.streammgmt.ResumePacket;
  77
  78public class XmppConnection implements Runnable {
  79
  80	private static final int PACKET_IQ = 0;
  81	private static final int PACKET_MESSAGE = 1;
  82	private static final int PACKET_PRESENCE = 2;
  83	private final Context applicationContext;
  84	protected Account account;
  85	private final WakeLock wakeLock;
  86	private Socket socket;
  87	private XmlReader tagReader;
  88	private TagWriter tagWriter;
  89	private final Features features = new Features(this);
  90	private boolean shouldBind = true;
  91	private boolean shouldAuthenticate = true;
  92	private Element streamFeatures;
  93	private final HashMap<String, List<String>> disco = new HashMap<>();
  94
  95	private String streamId = null;
  96	private int smVersion = 3;
  97	private final SparseArray<String> messageReceipts = new SparseArray<>();
  98
  99	private int stanzasReceived = 0;
 100	private int stanzasSent = 0;
 101	private long lastPacketReceived = 0;
 102	private long lastPingSent = 0;
 103	private long lastConnect = 0;
 104	private long lastSessionStarted = 0;
 105	private int attempt = 0;
 106	private final Map<String, Pair<IqPacket, OnIqPacketReceived>> packetCallbacks = new Hashtable<>();
 107	private OnPresencePacketReceived presenceListener = null;
 108	private OnJinglePacketReceived jingleListener = null;
 109	private OnIqPacketReceived unregisteredIqListener = null;
 110	private OnMessagePacketReceived messageListener = null;
 111	private OnStatusChanged statusListener = null;
 112	private OnBindListener bindListener = null;
 113	private final ArrayList<OnAdvancedStreamFeaturesLoaded> advancedStreamFeaturesLoadedListeners = new ArrayList<>();
 114	private OnMessageAcknowledged acknowledgedListener = null;
 115	private XmppConnectionService mXmppConnectionService = null;
 116
 117	private SaslMechanism saslMechanism;
 118
 119	public XmppConnection(final Account account, final XmppConnectionService service) {
 120		this.account = account;
 121		this.wakeLock = service.getPowerManager().newWakeLock(
 122				PowerManager.PARTIAL_WAKE_LOCK, account.getJid().toBareJid().toString());
 123		tagWriter = new TagWriter();
 124		mXmppConnectionService = service;
 125		applicationContext = service.getApplicationContext();
 126	}
 127
 128	protected void changeStatus(final Account.State nextStatus) {
 129		if (account.getStatus() != nextStatus) {
 130			if ((nextStatus == Account.State.OFFLINE)
 131					&& (account.getStatus() != Account.State.CONNECTING)
 132					&& (account.getStatus() != Account.State.ONLINE)
 133					&& (account.getStatus() != Account.State.DISABLED)) {
 134				return;
 135					}
 136			if (nextStatus == Account.State.ONLINE) {
 137				this.attempt = 0;
 138			}
 139			account.setStatus(nextStatus);
 140			if (statusListener != null) {
 141				statusListener.onStatusChanged(account);
 142			}
 143		}
 144	}
 145
 146	protected void connect() {
 147		Log.d(Config.LOGTAG, account.getJid().toBareJid().toString() + ": connecting");
 148		features.encryptionEnabled = false;
 149		lastConnect = SystemClock.elapsedRealtime();
 150		lastPingSent = SystemClock.elapsedRealtime();
 151		this.attempt++;
 152		try {
 153			shouldAuthenticate = shouldBind = !account.isOptionSet(Account.OPTION_REGISTER);
 154			tagReader = new XmlReader(wakeLock);
 155			tagWriter = new TagWriter();
 156			packetCallbacks.clear();
 157			this.changeStatus(Account.State.CONNECTING);
 158			final Bundle result = DNSHelper.getSRVRecord(account.getServer());
 159			final ArrayList<Parcelable> values = result.getParcelableArrayList("values");
 160			if ("timeout".equals(result.getString("error"))) {
 161				throw new IOException("timeout in dns");
 162			} else if (values != null) {
 163				int i = 0;
 164				boolean socketError = true;
 165				while (socketError && values.size() > i) {
 166					final Bundle namePort = (Bundle) values.get(i);
 167					try {
 168						String srvRecordServer;
 169						try {
 170							srvRecordServer=IDN.toASCII(namePort.getString("name"));
 171						} catch (final IllegalArgumentException e) {
 172							// TODO: Handle me?`
 173							srvRecordServer = "";
 174						}
 175						final int srvRecordPort = namePort.getInt("port");
 176						final String srvIpServer = namePort.getString("ip");
 177						final InetSocketAddress addr;
 178						if (srvIpServer != null) {
 179							addr = new InetSocketAddress(srvIpServer, srvRecordPort);
 180							Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
 181									+ ": using values from dns " + srvRecordServer
 182									+ "[" + srvIpServer + "]:" + srvRecordPort);
 183						} else {
 184							addr = new InetSocketAddress(srvRecordServer, srvRecordPort);
 185							Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
 186									+ ": using values from dns "
 187									+ srvRecordServer + ":" + srvRecordPort);
 188						}
 189						socket = new Socket();
 190						socket.connect(addr, 20000);
 191						socketError = false;
 192					} catch (final UnknownHostException e) {
 193						Log.d(Config.LOGTAG, account.getJid().toBareJid().toString() + ": " + e.getMessage());
 194						i++;
 195					} catch (final IOException e) {
 196						Log.d(Config.LOGTAG, account.getJid().toBareJid().toString() + ": " + e.getMessage());
 197						i++;
 198					}
 199				}
 200				if (socketError) {
 201					throw new UnknownHostException();
 202				}
 203			} else if (result.containsKey("error")
 204					&& "nosrv".equals(result.getString("error", null))) {
 205				socket = new Socket(account.getServer().getDomainpart(), 5222);
 206			} else {
 207				throw new IOException("unhandled exception in DNS resolver");
 208			}
 209			final OutputStream out = socket.getOutputStream();
 210			tagWriter.setOutputStream(out);
 211			final InputStream in = socket.getInputStream();
 212			tagReader.setInputStream(in);
 213			tagWriter.beginDocument();
 214			sendStartStream();
 215			Tag nextTag;
 216			while ((nextTag = tagReader.readTag()) != null) {
 217				if (nextTag.isStart("stream")) {
 218					processStream(nextTag);
 219					break;
 220				} else {
 221					throw new IOException("unknown tag on connect");
 222				}
 223			}
 224			if (socket.isConnected()) {
 225				socket.close();
 226			}
 227		} catch (final UnknownHostException | ConnectException e) {
 228			this.changeStatus(Account.State.SERVER_NOT_FOUND);
 229		} catch (final IOException | XmlPullParserException | NoSuchAlgorithmException e) {
 230			Log.d(Config.LOGTAG, account.getJid().toBareJid().toString() + ": " + e.getMessage());
 231			this.changeStatus(Account.State.OFFLINE);
 232			this.attempt--; //don't count attempt when reconnecting instantly anyway
 233		} finally {
 234			if (wakeLock.isHeld()) {
 235				try {
 236					wakeLock.release();
 237				} catch (final RuntimeException ignored) {
 238				}
 239			}
 240		}
 241	}
 242
 243	@Override
 244	public void run() {
 245		try {
 246			if (socket != null) {
 247				socket.close();
 248			}
 249		} catch (final IOException ignored) {
 250
 251		}
 252		connect();
 253	}
 254
 255	private void processStream(final Tag currentTag) throws XmlPullParserException,
 256					IOException, NoSuchAlgorithmException {
 257						Tag nextTag = tagReader.readTag();
 258
 259						while ((nextTag != null) && (!nextTag.isEnd("stream"))) {
 260							if (nextTag.isStart("error")) {
 261								processStreamError(nextTag);
 262							} else if (nextTag.isStart("features")) {
 263								processStreamFeatures(nextTag);
 264							} else if (nextTag.isStart("proceed")) {
 265								switchOverToTls(nextTag);
 266							} else if (nextTag.isStart("success")) {
 267								final String challenge = tagReader.readElement(nextTag).getContent();
 268								try {
 269									saslMechanism.getResponse(challenge);
 270								} catch (final SaslMechanism.AuthenticationException e) {
 271									disconnect(true);
 272									Log.e(Config.LOGTAG, String.valueOf(e));
 273								}
 274								Log.d(Config.LOGTAG, account.getJid().toBareJid().toString() + ": logged in");
 275								account.setKey(Account.PINNED_MECHANISM_KEY,
 276										String.valueOf(saslMechanism.getPriority()));
 277								tagReader.reset();
 278								sendStartStream();
 279								processStream(tagReader.readTag());
 280								break;
 281							} else if (nextTag.isStart("failure")) {
 282								tagReader.readElement(nextTag);
 283								changeStatus(Account.State.UNAUTHORIZED);
 284							} else if (nextTag.isStart("challenge")) {
 285								final String challenge = tagReader.readElement(nextTag).getContent();
 286								final Element response = new Element("response");
 287								response.setAttribute("xmlns",
 288										"urn:ietf:params:xml:ns:xmpp-sasl");
 289								try {
 290									response.setContent(saslMechanism.getResponse(challenge));
 291								} catch (final SaslMechanism.AuthenticationException e) {
 292									// TODO: Send auth abort tag.
 293									Log.e(Config.LOGTAG, e.toString());
 294								}
 295								tagWriter.writeElement(response);
 296							} else if (nextTag.isStart("enabled")) {
 297								final Element enabled = tagReader.readElement(nextTag);
 298								if ("true".equals(enabled.getAttribute("resume"))) {
 299									this.streamId = enabled.getAttribute("id");
 300									Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
 301											+ ": stream managment(" + smVersion
 302											+ ") enabled (resumable)");
 303								} else {
 304									Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
 305											+ ": stream managment(" + smVersion + ") enabled");
 306								}
 307								this.lastSessionStarted = SystemClock.elapsedRealtime();
 308								this.stanzasReceived = 0;
 309								final RequestPacket r = new RequestPacket(smVersion);
 310								tagWriter.writeStanzaAsync(r);
 311							} else if (nextTag.isStart("resumed")) {
 312								lastPacketReceived = SystemClock.elapsedRealtime();
 313								final Element resumed = tagReader.readElement(nextTag);
 314								final String h = resumed.getAttribute("h");
 315								try {
 316									final int serverCount = Integer.parseInt(h);
 317									if (serverCount != stanzasSent) {
 318										Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
 319												+ ": session resumed with lost packages");
 320										stanzasSent = serverCount;
 321									} else {
 322										Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
 323												+ ": session resumed");
 324									}
 325									if (acknowledgedListener != null) {
 326										for (int i = 0; i < messageReceipts.size(); ++i) {
 327											if (serverCount >= messageReceipts.keyAt(i)) {
 328												acknowledgedListener.onMessageAcknowledged(
 329														account, messageReceipts.valueAt(i));
 330											}
 331										}
 332									}
 333									messageReceipts.clear();
 334								} catch (final NumberFormatException ignored) {
 335								}
 336								sendServiceDiscoveryInfo(account.getServer());
 337								sendServiceDiscoveryItems(account.getServer());
 338								sendInitialPing();
 339							} else if (nextTag.isStart("r")) {
 340								tagReader.readElement(nextTag);
 341								final AckPacket ack = new AckPacket(this.stanzasReceived, smVersion);
 342								tagWriter.writeStanzaAsync(ack);
 343							} else if (nextTag.isStart("a")) {
 344								final Element ack = tagReader.readElement(nextTag);
 345								lastPacketReceived = SystemClock.elapsedRealtime();
 346								final int serverSequence = Integer.parseInt(ack.getAttribute("h"));
 347								final String msgId = this.messageReceipts.get(serverSequence);
 348								if (msgId != null) {
 349									if (this.acknowledgedListener != null) {
 350										this.acknowledgedListener.onMessageAcknowledged(
 351												account, msgId);
 352									}
 353									this.messageReceipts.remove(serverSequence);
 354								}
 355							} else if (nextTag.isStart("failed")) {
 356								tagReader.readElement(nextTag);
 357								Log.d(Config.LOGTAG, account.getJid().toBareJid().toString() + ": resumption failed");
 358								streamId = null;
 359								if (account.getStatus() != Account.State.ONLINE) {
 360									sendBindRequest();
 361								}
 362							} else if (nextTag.isStart("iq")) {
 363								processIq(nextTag);
 364							} else if (nextTag.isStart("message")) {
 365								processMessage(nextTag);
 366							} else if (nextTag.isStart("presence")) {
 367								processPresence(nextTag);
 368							}
 369							nextTag = tagReader.readTag();
 370						}
 371						if (account.getStatus() == Account.State.ONLINE) {
 372							account. setStatus(Account.State.OFFLINE);
 373							if (statusListener != null) {
 374								statusListener.onStatusChanged(account);
 375							}
 376						}
 377	}
 378
 379	private void sendInitialPing() {
 380		Log.d(Config.LOGTAG, account.getJid().toBareJid().toString() + ": sending intial ping");
 381		final IqPacket iq = new IqPacket(IqPacket.TYPE.GET);
 382		iq.setFrom(account.getJid());
 383		iq.addChild("ping", "urn:xmpp:ping");
 384		this.sendIqPacket(iq, new OnIqPacketReceived() {
 385			@Override
 386			public void onIqPacketReceived(final Account account, final IqPacket packet) {
 387				Log.d(Config.LOGTAG, account.getJid().toBareJid().toString()
 388						+ ": online with resource " + account.getResource());
 389				changeStatus(Account.State.ONLINE);
 390			}
 391		});
 392	}
 393
 394	private Element processPacket(final Tag currentTag, final int packetType)
 395		throws XmlPullParserException, IOException {
 396		Element element;
 397		switch (packetType) {
 398			case PACKET_IQ:
 399				element = new IqPacket();
 400				break;
 401			case PACKET_MESSAGE:
 402				element = new MessagePacket();
 403				break;
 404			case PACKET_PRESENCE:
 405				element = new PresencePacket();
 406				break;
 407			default:
 408				return null;
 409		}
 410		element.setAttributes(currentTag.getAttributes());
 411		Tag nextTag = tagReader.readTag();
 412		if (nextTag == null) {
 413			throw new IOException("interrupted mid tag");
 414		}
 415		while (!nextTag.isEnd(element.getName())) {
 416			if (!nextTag.isNo()) {
 417				final Element child = tagReader.readElement(nextTag);
 418				final String type = currentTag.getAttribute("type");
 419				if (packetType == PACKET_IQ
 420						&& "jingle".equals(child.getName())
 421						&& ("set".equalsIgnoreCase(type) || "get"
 422							.equalsIgnoreCase(type))) {
 423					element = new JinglePacket();
 424					element.setAttributes(currentTag.getAttributes());
 425							}
 426				element.addChild(child);
 427			}
 428			nextTag = tagReader.readTag();
 429			if (nextTag == null) {
 430				throw new IOException("interrupted mid tag");
 431			}
 432		}
 433		++stanzasReceived;
 434		lastPacketReceived = SystemClock.elapsedRealtime();
 435		return element;
 436	}
 437
 438	private void processIq(final Tag currentTag) throws XmlPullParserException, IOException {
 439		final IqPacket packet = (IqPacket) processPacket(currentTag, PACKET_IQ);
 440
 441		if (packet.getId() == null) {
 442			return; // an iq packet without id is definitely invalid
 443		}
 444
 445		if (packet instanceof JinglePacket) {
 446			if (this.jingleListener != null) {
 447				this.jingleListener.onJinglePacketReceived(account,(JinglePacket) packet);
 448			}
 449		} else {
 450			if (packetCallbacks.containsKey(packet.getId())) {
 451				final Pair<IqPacket, OnIqPacketReceived> packetCallbackDuple = packetCallbacks.get(packet.getId());
 452				// Packets to the server should have responses from the server
 453				if (packetCallbackDuple.first.toServer(account)) {
 454					if (packet.fromServer(account)) {
 455						packetCallbackDuple.second.onIqPacketReceived(account, packet);
 456						packetCallbacks.remove(packet.getId());
 457					} else {
 458						Log.e(Config.LOGTAG,account.getJid().toBareJid().toString()+": ignoring spoofed iq packet");
 459					}
 460				} else {
 461					if (packet.getFrom().equals(packetCallbackDuple.first.getTo())) {
 462						packetCallbackDuple.second.onIqPacketReceived(account, packet);
 463						packetCallbacks.remove(packet.getId());
 464					} else {
 465						Log.e(Config.LOGTAG,account.getJid().toBareJid().toString()+": ignoring spoofed iq packet");
 466					}
 467				}
 468			} else if (packet.getType() == IqPacket.TYPE.GET|| packet.getType() == IqPacket.TYPE.SET) {
 469				this.unregisteredIqListener.onIqPacketReceived(account, packet);
 470			}
 471		}
 472	}
 473
 474	private void processMessage(final Tag currentTag) throws XmlPullParserException, IOException {
 475		final MessagePacket packet = (MessagePacket) processPacket(currentTag,PACKET_MESSAGE);
 476		this.messageListener.onMessagePacketReceived(account, packet);
 477	}
 478
 479	private void processPresence(final Tag currentTag) throws XmlPullParserException, IOException {
 480		PresencePacket packet = (PresencePacket) processPacket(currentTag, PACKET_PRESENCE);
 481		this.presenceListener.onPresencePacketReceived(account, packet);
 482	}
 483
 484	private void sendStartTLS() throws IOException {
 485		final Tag startTLS = Tag.empty("starttls");
 486		startTLS.setAttribute("xmlns", "urn:ietf:params:xml:ns:xmpp-tls");
 487		tagWriter.writeTag(startTLS);
 488	}
 489
 490	private SharedPreferences getPreferences() {
 491		return PreferenceManager.getDefaultSharedPreferences(applicationContext);
 492	}
 493
 494	private boolean enableLegacySSL() {
 495		return getPreferences().getBoolean("enable_legacy_ssl", false);
 496	}
 497
 498	private void switchOverToTls(final Tag currentTag) throws XmlPullParserException, IOException {
 499		tagReader.readTag();
 500		try {
 501			final SSLContext sc = SSLContext.getInstance("TLS");
 502			sc.init(null,new X509TrustManager[]{this.mXmppConnectionService.getMemorizingTrustManager()},mXmppConnectionService.getRNG());
 503			final SSLSocketFactory factory = sc.getSocketFactory();
 504			final HostnameVerifier verifier = this.mXmppConnectionService.getMemorizingTrustManager().wrapHostnameVerifier(new StrictHostnameVerifier());
 505			final InetAddress address = socket == null ? null : socket.getInetAddress();
 506
 507			if (factory == null || address == null || verifier == null) {
 508				throw new IOException("could not setup ssl");
 509			}
 510
 511			final SSLSocket sslSocket = (SSLSocket) factory.createSocket(socket,address.getHostAddress(), socket.getPort(),true);
 512
 513			if (sslSocket == null) {
 514				throw new IOException("could not initialize ssl socket");
 515			}
 516
 517			final String[] supportProtocols;
 518			final Collection<String> supportedProtocols = new LinkedList<>(
 519					Arrays.asList(sslSocket.getSupportedProtocols()));
 520			supportedProtocols.remove("SSLv3");
 521			supportProtocols = supportedProtocols.toArray(new String[supportedProtocols.size()]);
 522
 523			sslSocket.setEnabledProtocols(supportProtocols);
 524
 525			final String[] cipherSuites = CryptoHelper.getOrderedCipherSuites(
 526					sslSocket.getSupportedCipherSuites());
 527			//Log.d(Config.LOGTAG, "Using ciphers: " + Arrays.toString(cipherSuites));
 528			if (cipherSuites.length > 0) {
 529				sslSocket.setEnabledCipherSuites(cipherSuites);
 530			}
 531
 532			if (!verifier.verify(account.getServer().getDomainpart(),sslSocket.getSession())) {
 533				Log.d(Config.LOGTAG,account.getJid().toBareJid()+": TLS certificate verification failed");
 534				disconnect(true);
 535				changeStatus(Account.State.SECURITY_ERROR);
 536			}
 537			tagReader.setInputStream(sslSocket.getInputStream());
 538			tagWriter.setOutputStream(sslSocket.getOutputStream());
 539			sendStartStream();
 540			Log.d(Config.LOGTAG, account.getJid().toBareJid()+ ": TLS connection established");
 541			features.encryptionEnabled = true;
 542			processStream(tagReader.readTag());
 543			sslSocket.close();
 544		} catch (final NoSuchAlgorithmException | KeyManagementException e1) {
 545			Log.d(Config.LOGTAG,account.getJid().toBareJid()+": TLS certificate verification failed");
 546			disconnect(true);
 547			changeStatus(Account.State.SECURITY_ERROR);
 548		}
 549	}
 550
 551	private void processStreamFeatures(final Tag currentTag)
 552		throws XmlPullParserException, IOException {
 553		this.streamFeatures = tagReader.readElement(currentTag);
 554		if (this.streamFeatures.hasChild("starttls") && !features.encryptionEnabled) {
 555			sendStartTLS();
 556		} else if (this.streamFeatures.hasChild("register")
 557				&& account.isOptionSet(Account.OPTION_REGISTER)
 558				&& features.encryptionEnabled) {
 559			sendRegistryRequest();
 560		} else if (!this.streamFeatures.hasChild("register")
 561				&& account.isOptionSet(Account.OPTION_REGISTER)) {
 562			changeStatus(Account.State.REGISTRATION_NOT_SUPPORTED);
 563			disconnect(true);
 564		} else if (this.streamFeatures.hasChild("mechanisms")
 565				&& shouldAuthenticate && features.encryptionEnabled) {
 566			final List<String> mechanisms = extractMechanisms(streamFeatures
 567					.findChild("mechanisms"));
 568			final Element auth = new Element("auth");
 569			auth.setAttribute("xmlns", "urn:ietf:params:xml:ns:xmpp-sasl");
 570			if (mechanisms.contains("SCRAM-SHA-1")) {
 571				saslMechanism = new ScramSha1(tagWriter, account, mXmppConnectionService.getRNG());
 572			} else if (mechanisms.contains("PLAIN")) {
 573				saslMechanism = new Plain(tagWriter, account);
 574			} else if (mechanisms.contains("DIGEST-MD5")) {
 575				saslMechanism = new DigestMd5(tagWriter, account, mXmppConnectionService.getRNG());
 576			}
 577			final JSONObject keys = account.getKeys();
 578			try {
 579				if (keys.has(Account.PINNED_MECHANISM_KEY) &&
 580						keys.getInt(Account.PINNED_MECHANISM_KEY) > saslMechanism.getPriority() ) {
 581					Log.e(Config.LOGTAG, "Auth failed. Authentication mechanism " + saslMechanism.getMechanism() +
 582							" has lower priority (" + String.valueOf(saslMechanism.getPriority()) +
 583							") than pinned priority (" + keys.getInt(Account.PINNED_MECHANISM_KEY) +
 584							"). Possible downgrade attack?");
 585					disconnect(true);
 586					changeStatus(Account.State.SECURITY_ERROR);
 587						}
 588			} catch (final JSONException e) {
 589				Log.d(Config.LOGTAG, "Parse error while checking pinned auth mechanism");
 590			}
 591			Log.d(Config.LOGTAG,account.getJid().toString()+": Authenticating with " + saslMechanism.getMechanism());
 592			auth.setAttribute("mechanism", saslMechanism.getMechanism());
 593			if (!saslMechanism.getClientFirstMessage().isEmpty()) {
 594				auth.setContent(saslMechanism.getClientFirstMessage());
 595			}
 596			tagWriter.writeElement(auth);
 597		} else if (this.streamFeatures.hasChild("sm", "urn:xmpp:sm:"
 598					+ smVersion)
 599				&& streamId != null) {
 600			final ResumePacket resume = new ResumePacket(this.streamId,
 601					stanzasReceived, smVersion);
 602			this.tagWriter.writeStanzaAsync(resume);
 603		} else if (this.streamFeatures.hasChild("bind") && shouldBind) {
 604			sendBindRequest();
 605		} else {
 606			disconnect(true);
 607			changeStatus(Account.State.INCOMPATIBLE_SERVER);
 608		}
 609	}
 610
 611	private List<String> extractMechanisms(final Element stream) {
 612		final ArrayList<String> mechanisms = new ArrayList<>(stream
 613				.getChildren().size());
 614		for (final Element child : stream.getChildren()) {
 615			mechanisms.add(child.getContent());
 616		}
 617		return mechanisms;
 618	}
 619
 620	private void sendRegistryRequest() {
 621		final IqPacket register = new IqPacket(IqPacket.TYPE.GET);
 622		register.query("jabber:iq:register");
 623		register.setTo(account.getServer());
 624		sendIqPacket(register, new OnIqPacketReceived() {
 625
 626			@Override
 627			public void onIqPacketReceived(final Account account, final IqPacket packet) {
 628				final Element instructions = packet.query().findChild("instructions");
 629				if (packet.query().hasChild("username")
 630						&& (packet.query().hasChild("password"))) {
 631					final IqPacket register = new IqPacket(IqPacket.TYPE.SET);
 632					final Element username = new Element("username")
 633						.setContent(account.getUsername());
 634					final Element password = new Element("password")
 635						.setContent(account.getPassword());
 636					register.query("jabber:iq:register").addChild(username);
 637					register.query().addChild(password);
 638					sendIqPacket(register, new OnIqPacketReceived() {
 639
 640						@Override
 641						public void onIqPacketReceived(final Account account, final IqPacket packet) {
 642							if (packet.getType() == IqPacket.TYPE.RESULT) {
 643								account.setOption(Account.OPTION_REGISTER,
 644										false);
 645								changeStatus(Account.State.REGISTRATION_SUCCESSFUL);
 646							} else if (packet.hasChild("error")
 647									&& (packet.findChild("error")
 648										.hasChild("conflict"))) {
 649								changeStatus(Account.State.REGISTRATION_CONFLICT);
 650							} else {
 651								changeStatus(Account.State.REGISTRATION_FAILED);
 652								Log.d(Config.LOGTAG, packet.toString());
 653							}
 654							disconnect(true);
 655						}
 656					});
 657				} else {
 658					changeStatus(Account.State.REGISTRATION_FAILED);
 659					disconnect(true);
 660					Log.d(Config.LOGTAG, account.getJid().toBareJid()
 661							+ ": could not register. instructions are"
 662							+ instructions.getContent());
 663				}
 664			}
 665		});
 666	}
 667
 668	private void sendBindRequest() {
 669		while(!mXmppConnectionService.areMessagesInitialized()) {
 670			try {
 671				Thread.sleep(500);
 672			} catch (final InterruptedException ignored) {
 673			}
 674		}
 675		final IqPacket iq = new IqPacket(IqPacket.TYPE.SET);
 676		iq.addChild("bind", "urn:ietf:params:xml:ns:xmpp-bind")
 677			.addChild("resource").setContent(account.getResource());
 678		this.sendUnmodifiedIqPacket(iq, new OnIqPacketReceived() {
 679			@Override
 680			public void onIqPacketReceived(final Account account, final IqPacket packet) {
 681				final Element bind = packet.findChild("bind");
 682				if (bind != null) {
 683					final Element jid = bind.findChild("jid");
 684					if (jid != null && jid.getContent() != null) {
 685						try {
 686							account.setResource(Jid.fromString(jid.getContent()).getResourcepart());
 687						} catch (final InvalidJidException e) {
 688							// TODO: Handle the case where an external JID is technically invalid?
 689						}
 690						if (streamFeatures.hasChild("session")) {
 691							sendStartSession();
 692						} else {
 693							sendPostBindInitialization();
 694						}
 695					} else {
 696						disconnect(true);
 697					}
 698				} else {
 699					disconnect(true);
 700				}
 701			}
 702		});
 703	}
 704
 705	private void sendStartSession() {
 706		final IqPacket startSession = new IqPacket(IqPacket.TYPE.SET);
 707		startSession.addChild("session","urn:ietf:params:xml:ns:xmpp-session");
 708		this.sendUnmodifiedIqPacket(startSession, new OnIqPacketReceived() {
 709			@Override
 710			public void onIqPacketReceived(Account account, IqPacket packet) {
 711				if (packet.getType() == IqPacket.TYPE.RESULT) {
 712					sendPostBindInitialization();
 713				} else {
 714					disconnect(true);
 715				}
 716			}
 717		});
 718	}
 719
 720	private void sendPostBindInitialization() {
 721		smVersion = 0;
 722		if (streamFeatures.hasChild("sm", "urn:xmpp:sm:3")) {
 723			smVersion = 3;
 724		} else if (streamFeatures.hasChild("sm", "urn:xmpp:sm:2")) {
 725			smVersion = 2;
 726		}
 727		if (smVersion != 0) {
 728			final EnablePacket enable = new EnablePacket(smVersion);
 729			tagWriter.writeStanzaAsync(enable);
 730			stanzasSent = 0;
 731			messageReceipts.clear();
 732		}
 733		features.carbonsEnabled = false;
 734		features.blockListRequested = false;
 735		disco.clear();
 736		sendServiceDiscoveryInfo(account.getServer());
 737		sendServiceDiscoveryItems(account.getServer());
 738		if (bindListener != null) {
 739			bindListener.onBind(account);
 740		}
 741		sendInitialPing();
 742	}
 743
 744	private void sendServiceDiscoveryInfo(final Jid server) {
 745		if (disco.containsKey(server.toDomainJid().toString())) {
 746			if (account.getServer().equals(server.toDomainJid())) {
 747				enableAdvancedStreamFeatures();
 748			}
 749		} else {
 750			final IqPacket iq = new IqPacket(IqPacket.TYPE.GET);
 751			iq.setTo(server.toDomainJid());
 752			iq.query("http://jabber.org/protocol/disco#info");
 753			this.sendIqPacket(iq, new OnIqPacketReceived() {
 754
 755				@Override
 756				public void onIqPacketReceived(final Account account, final IqPacket packet) {
 757					final List<Element> elements = packet.query().getChildren();
 758					final List<String> features = new ArrayList<>();
 759					for (final Element element : elements) {
 760						if (element.getName().equals("identity")) {
 761							if ("irc".equals(element.getAttribute("type"))) {
 762								//add fake feature to not confuse irc and real muc
 763								features.add("siacs:no:muc");
 764							}
 765						} else if (element.getName().equals("feature")) {
 766							features.add(element.getAttribute("var"));
 767						}
 768					}
 769					disco.put(server.toDomainJid().toString(), features);
 770
 771					if (account.getServer().equals(server.toDomainJid())) {
 772						enableAdvancedStreamFeatures();
 773						for (final OnAdvancedStreamFeaturesLoaded listener : advancedStreamFeaturesLoadedListeners) {
 774							listener.onAdvancedStreamFeaturesAvailable(account);
 775						}
 776					}
 777				}
 778			});
 779		}
 780	}
 781
 782	private void enableAdvancedStreamFeatures() {
 783		if (getFeatures().carbons() && !features.carbonsEnabled) {
 784			sendEnableCarbons();
 785		}
 786		if (getFeatures().blocking() && !features.blockListRequested) {
 787			Log.d(Config.LOGTAG, "Requesting block list");
 788			this.sendIqPacket(getIqGenerator().generateGetBlockList(), mXmppConnectionService.getIqParser());
 789		}
 790	}
 791
 792	private void sendServiceDiscoveryItems(final Jid server) {
 793		final IqPacket iq = new IqPacket(IqPacket.TYPE.GET);
 794		iq.setTo(server.toDomainJid());
 795		iq.query("http://jabber.org/protocol/disco#items");
 796		this.sendIqPacket(iq, new OnIqPacketReceived() {
 797
 798			@Override
 799			public void onIqPacketReceived(final Account account, final IqPacket packet) {
 800				final List<Element> elements = packet.query().getChildren();
 801				for (final Element element : elements) {
 802					if (element.getName().equals("item")) {
 803						final Jid jid = element.getAttributeAsJid("jid");
 804						if (jid != null && !jid.equals(account.getServer())) {
 805							sendServiceDiscoveryInfo(jid);
 806						}
 807					}
 808				}
 809			}
 810		});
 811	}
 812
 813	private void sendEnableCarbons() {
 814		final IqPacket iq = new IqPacket(IqPacket.TYPE.SET);
 815		iq.addChild("enable", "urn:xmpp:carbons:2");
 816		this.sendIqPacket(iq, new OnIqPacketReceived() {
 817
 818			@Override
 819			public void onIqPacketReceived(final Account account, final IqPacket packet) {
 820				if (!packet.hasChild("error")) {
 821					Log.d(Config.LOGTAG, account.getJid().toBareJid()
 822							+ ": successfully enabled carbons");
 823					features.carbonsEnabled = true;
 824				} else {
 825					Log.d(Config.LOGTAG, account.getJid().toBareJid()
 826							+ ": error enableing carbons " + packet.toString());
 827				}
 828			}
 829		});
 830	}
 831
 832	private void processStreamError(final Tag currentTag)
 833		throws XmlPullParserException, IOException {
 834		final Element streamError = tagReader.readElement(currentTag);
 835		if (streamError != null && streamError.hasChild("conflict")) {
 836			final String resource = account.getResource().split("\\.")[0];
 837			account.setResource(resource + "." + nextRandomId());
 838			Log.d(Config.LOGTAG,
 839					account.getJid().toBareJid() + ": switching resource due to conflict ("
 840					+ account.getResource() + ")");
 841		}
 842	}
 843
 844	private void sendStartStream() throws IOException {
 845		final Tag stream = Tag.start("stream:stream");
 846		stream.setAttribute("from", account.getJid().toBareJid().toString());
 847		stream.setAttribute("to", account.getServer().toString());
 848		stream.setAttribute("version", "1.0");
 849		stream.setAttribute("xml:lang", "en");
 850		stream.setAttribute("xmlns", "jabber:client");
 851		stream.setAttribute("xmlns:stream", "http://etherx.jabber.org/streams");
 852		tagWriter.writeTag(stream);
 853	}
 854
 855	private String nextRandomId() {
 856		return new BigInteger(50, mXmppConnectionService.getRNG()).toString(32);
 857	}
 858
 859	public void sendIqPacket(final IqPacket packet, final OnIqPacketReceived callback) {
 860		packet.setFrom(account.getJid());
 861		this.sendUnmodifiedIqPacket(packet,callback);
 862
 863	}
 864
 865	private synchronized void sendUnmodifiedIqPacket(final IqPacket packet, final OnIqPacketReceived callback) {
 866		if (packet.getId() == null) {
 867			final String id = nextRandomId();
 868			packet.setAttribute("id", id);
 869		}
 870		if (callback != null) {
 871			if (packet.getId() == null) {
 872				packet.setId(nextRandomId());
 873			}
 874			packetCallbacks.put(packet.getId(), new Pair<>(packet, callback));
 875		}
 876		this.sendPacket(packet);
 877	}
 878
 879	public void sendMessagePacket(final MessagePacket packet) {
 880		this.sendPacket(packet);
 881	}
 882
 883	public void sendPresencePacket(final PresencePacket packet) {
 884		this.sendPacket(packet);
 885	}
 886
 887	private synchronized void sendPacket(final AbstractStanza packet) {
 888		final String name = packet.getName();
 889		if (name.equals("iq") || name.equals("message") || name.equals("presence")) {
 890			++stanzasSent;
 891		}
 892		tagWriter.writeStanzaAsync(packet);
 893		if (packet instanceof MessagePacket && packet.getId() != null && this.streamId != null) {
 894			Log.d(Config.LOGTAG, "request delivery report for stanza " + stanzasSent);
 895			this.messageReceipts.put(stanzasSent, packet.getId());
 896			tagWriter.writeStanzaAsync(new RequestPacket(this.smVersion));
 897		}
 898	}
 899
 900	public void sendPing() {
 901		if (streamFeatures.hasChild("sm")) {
 902			tagWriter.writeStanzaAsync(new RequestPacket(smVersion));
 903		} else {
 904			final IqPacket iq = new IqPacket(IqPacket.TYPE.GET);
 905			iq.setFrom(account.getJid());
 906			iq.addChild("ping", "urn:xmpp:ping");
 907			this.sendIqPacket(iq, null);
 908		}
 909		this.lastPingSent = SystemClock.elapsedRealtime();
 910	}
 911
 912	public void setOnMessagePacketReceivedListener(
 913			final OnMessagePacketReceived listener) {
 914		this.messageListener = listener;
 915			}
 916
 917	public void setOnUnregisteredIqPacketReceivedListener(
 918			final OnIqPacketReceived listener) {
 919		this.unregisteredIqListener = listener;
 920			}
 921
 922	public void setOnPresencePacketReceivedListener(
 923			final OnPresencePacketReceived listener) {
 924		this.presenceListener = listener;
 925			}
 926
 927	public void setOnJinglePacketReceivedListener(
 928			final OnJinglePacketReceived listener) {
 929		this.jingleListener = listener;
 930			}
 931
 932	public void setOnStatusChangedListener(final OnStatusChanged listener) {
 933		this.statusListener = listener;
 934	}
 935
 936	public void setOnBindListener(final OnBindListener listener) {
 937		this.bindListener = listener;
 938	}
 939
 940	public void setOnMessageAcknowledgeListener(final OnMessageAcknowledged listener) {
 941		this.acknowledgedListener = listener;
 942	}
 943
 944	public void addOnAdvancedStreamFeaturesAvailableListener(final OnAdvancedStreamFeaturesLoaded listener) {
 945		if (!this.advancedStreamFeaturesLoadedListeners.contains(listener)) {
 946			this.advancedStreamFeaturesLoadedListeners.add(listener);
 947		}
 948	}
 949
 950	public void disconnect(final boolean force) {
 951		Log.d(Config.LOGTAG, account.getJid().toBareJid() + ": disconnecting");
 952		try {
 953			if (force) {
 954				socket.close();
 955				return;
 956			}
 957			new Thread(new Runnable() {
 958
 959				@Override
 960				public void run() {
 961					if (tagWriter.isActive()) {
 962						tagWriter.finish();
 963						try {
 964							while (!tagWriter.finished()) {
 965								Log.d(Config.LOGTAG, "not yet finished");
 966								Thread.sleep(100);
 967							}
 968							tagWriter.writeTag(Tag.end("stream:stream"));
 969							socket.close();
 970						} catch (final IOException e) {
 971							Log.d(Config.LOGTAG,
 972									"io exception during disconnect");
 973						} catch (final InterruptedException e) {
 974							Log.d(Config.LOGTAG, "interrupted");
 975						}
 976					}
 977				}
 978			}).start();
 979		} catch (final IOException e) {
 980			Log.d(Config.LOGTAG, "io exception during disconnect");
 981		}
 982	}
 983
 984	public List<String> findDiscoItemsByFeature(final String feature) {
 985		final List<String> items = new ArrayList<>();
 986		for (final Entry<String, List<String>> cursor : disco.entrySet()) {
 987			if (cursor.getValue().contains(feature)) {
 988				items.add(cursor.getKey());
 989			}
 990		}
 991		return items;
 992	}
 993
 994	public String findDiscoItemByFeature(final String feature) {
 995		final List<String> items = findDiscoItemsByFeature(feature);
 996		if (items.size() >= 1) {
 997			return items.get(0);
 998		}
 999		return null;
1000	}
1001
1002	public void r() {
1003		this.tagWriter.writeStanzaAsync(new RequestPacket(smVersion));
1004	}
1005
1006	public String getMucServer() {
1007		for (final Entry<String, List<String>> cursor : disco.entrySet()) {
1008			final List<String> value = cursor.getValue();
1009			if (value.contains("http://jabber.org/protocol/muc") && !value.contains("jabber:iq:gateway") && !value.contains("siacs:no:muc")) {
1010				return cursor.getKey();
1011			}
1012		}
1013		return null;
1014	}
1015
1016	public int getTimeToNextAttempt() {
1017		final int interval = (int) (25 * Math.pow(1.5, attempt));
1018		final int secondsSinceLast = (int) ((SystemClock.elapsedRealtime() - this.lastConnect) / 1000);
1019		return interval - secondsSinceLast;
1020	}
1021
1022	public int getAttempt() {
1023		return this.attempt;
1024	}
1025
1026	public Features getFeatures() {
1027		return this.features;
1028	}
1029
1030	public long getLastSessionEstablished() {
1031		final long diff;
1032		if (this.lastSessionStarted == 0) {
1033			diff = SystemClock.elapsedRealtime() - this.lastConnect;
1034		} else {
1035			diff = SystemClock.elapsedRealtime() - this.lastSessionStarted;
1036		}
1037		return System.currentTimeMillis() - diff;
1038	}
1039
1040	public long getLastConnect() {
1041		return this.lastConnect;
1042	}
1043
1044	public long getLastPingSent() {
1045		return this.lastPingSent;
1046	}
1047
1048	public long getLastPacketReceived() {
1049		return this.lastPacketReceived;
1050	}
1051
1052	public void sendActive() {
1053		this.sendPacket(new ActivePacket());
1054	}
1055
1056	public void sendInactive() {
1057		this.sendPacket(new InactivePacket());
1058	}
1059
1060	public void resetAttemptCount() {
1061		this.attempt = 0;
1062		this.lastConnect = 0;
1063	}
1064
1065	public class Features {
1066		XmppConnection connection;
1067		private boolean carbonsEnabled = false;
1068		private boolean encryptionEnabled = false;
1069		private boolean blockListRequested = false;
1070
1071		public Features(final XmppConnection connection) {
1072			this.connection = connection;
1073		}
1074
1075		private boolean hasDiscoFeature(final Jid server, final String feature) {
1076			return connection.disco.containsKey(server.toDomainJid().toString()) &&
1077				connection.disco.get(server.toDomainJid().toString()).contains(feature);
1078		}
1079
1080		public boolean carbons() {
1081			return hasDiscoFeature(account.getServer(), "urn:xmpp:carbons:2");
1082		}
1083
1084		public boolean blocking() {
1085			return hasDiscoFeature(account.getServer(), Xmlns.BLOCKING);
1086		}
1087
1088		public boolean register() {
1089			return hasDiscoFeature(account.getServer(), Xmlns.REGISTER);
1090		}
1091
1092		public boolean sm() {
1093			return streamId != null;
1094		}
1095
1096		public boolean csi() {
1097			return connection.streamFeatures != null && connection.streamFeatures.hasChild("csi", "urn:xmpp:csi:0");
1098		}
1099
1100		public boolean pubsub() {
1101			return hasDiscoFeature(account.getServer(),
1102					"http://jabber.org/protocol/pubsub#publish");
1103		}
1104
1105		public boolean mam() {
1106			return hasDiscoFeature(account.getServer(), "urn:xmpp:mam:0");
1107		}
1108
1109		public boolean advancedStreamFeaturesLoaded() {
1110			return disco.containsKey(account.getServer().toString());
1111		}
1112
1113		public boolean rosterVersioning() {
1114			return connection.streamFeatures != null && connection.streamFeatures.hasChild("ver");
1115		}
1116
1117		public void setBlockListRequested(boolean value) {
1118			this.blockListRequested = value;
1119		}
1120	}
1121
1122	private IqGenerator getIqGenerator() {
1123		return mXmppConnectionService.getIqGenerator();
1124	}
1125}